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PubMed2005

Power from below: enabling communities to ensure the provision of iodated salt in Kyrgyzstan.

BACKGROUND: In Kyrgyzstan, as in many countries around the world, progress in universal salt iodization has been slow because of difficulties in enforcing existing national regulations. OBJECTIVE: To study the effects of community testing of the iodine content of salt in households, at local retailers, and at wholesale markets on the percentage of households using iodized salt in Naryn Oblast, a region of Kyrgyzstan. METHODS: In response to a stated community priority to address iodine deficiency in Naryn Oblast, volunteers from village health committees and personnel of Primary Health Care units living in the communities were trained in testing salt using test kits. A phased introduction of two testing components was conducted in 2002-2003 in two areas with a combined population of 160,000. The two components included testing of salt for iodine content by community members in as many households as possible (Component 1) and testing of retail salt for iodate content by community members and by retailers at wholesale markets (Component 2). Results from these two components provided the data for this study. RESULTS: For Component 1, salt testing reached 65% of households; coverage of iodized salt increased from 87.6% to 96.8% within 5 to 7 months (averages of the two areas; p < .001), mostly owing to a great decrease in the variation among settlements. For Component 2, in area 1, the percentage of households using iodated salt increased from 71.0% to 90.3% within 5 to 7 months, whereas the percentage of households using iodinated salt decreased from 18.6% to 5.6%. In area 2, the percentage of households using iodated salt increased from 65.2% to 76.2% within 5 to 7 months, with no change in the percentage of households using iodinated salt (21.7% and 20.8%). The differences between areas I and 2 are highly significant (p < .001). At 18 to 21 months, the percentage of households using iodated salt was 97.5% in area 1 and 90.2% in area 2. The intervention cost around U.S. dollars 1500. CONCLUSIONS: Testing salt in a large percentage of households is an effective, low-cost approach to increasing the percentage of households using iodized salt to satisfactory levels in a very short time. Empowering community members to check salt at retailers and retailers to check salt at wholesale markets with test kits for iodated salt can rapidly ensure almost exclusive consumption of iodated salt in households.

Developing Countries↗
PubMed2006

[Biodiversity of halophilic archaea isolated from two salt lakes in Xin-Jiang region of China].

There are more than 1000 salt lakes situated in northern and western regions of China and 790 of these salt lakes are in Xinjiang Uigur Autonomous Region and Qinghai, Tibet, Inner Mongolia. To better understand halophilic archaeal diversity of salt lakes in Xinjiang, water and sediment samples were collected from two salt lakes, namely Aibi salt lake and Aiding salt lake, and the halophilic archaeal diversity of these samples was determined. Totally eighty-six halophilic archeal strains, of which 56 isolated from Aibi salt lake and 30 isolated from Aiding salt lake, were isolated respectively using CM agar medium. All the strains were subjected to 16S rRNA gene sequencing analysis. Similarity analysis based on 16S rRNA gene sequences of all these strains indicated that the isolates from Aibi salt lake belong to 11 different species of genera Haloarcula, Halobacterium, Halorubrum, Haloterrigena, Natrinema and Natronorubrum, and that the isolates from Aiding salt lake belong to 8 different species of genera Haloarcula, Halobiforma, Halorubrum, Haloterrigena, Natrinema. Among the 86 strains, members of Natronorubrum Natrinema, Halorubrum and Haloterrigena, are dominant groups in Aibi salt lake. However, the dominant group in Aibi salt lake are the members of Natrinema, Halorubrum and Haloterrigena. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains ABH13, ABH 14, ABH 15, ABH 18, ABH 31 and ABH 33 may represent a novel species of Natronorubrum; ABH12, ABH32 and AD30 two novel species of Halorubrum; ABH17 and ABH25, ABH51, ABH52, ABH56 two novel species of Haloterrigena respectively; strain ABH19 a novel species of Haloarcula; strain ABHO7 a novel species of Halobacterium. The Shannon-Wiener's index of Aibi salt lake is 1.899, the same index of Aiding salt lake is 1.317, which indicated that the biodiversity of halophilic archaea from Aibi salt lake was slightly higher than that of Aiding salt lake. Different characteristics in pH of salt concentrations, average annual precipitation, annual evaporation and mankind's impact on two salt lakes might play important roles on halophilic archaeal diversity of two salt lakes.

Biodiversity↗
PubMed2005

Investigation of solubility and dissolution of a free base and two different salt forms as a function of pH.

PURPOSE: To evaluate the effect of pH on solubility and dissolution rates of a model weak base, haloperidol, and two different salt forms, hydrochloride and mesylate. METHODS: pH-solubility profiles were determined by using haloperidol base, haloperidol hydrochloride, and haloperidol mesylate as starting materials; concentrated or diluted HCl or NaOH solutions were added to aqueous suspensions of solids to adjust pH to desired values. Intrinsic dissolution rates were determined using intrinsic dissolution apparatus under various pH-stat conditions. Further, approximation of diffusion layer pH was estimated from that of 10% w/w slurries of drug substances in dissolution media, which were used to correlate with intrinsic dissolution rates of haloperidol and its salt forms under different pHs. RESULTS: pH-solubility profiles of haloperidol base and its HCl salt were similar, while when the mesylate salt was used as starting material, it exhibited a higher solubility between pH 2 and 5. The higher solubility of the mesylate salt at pH 2-5 is attributed to its higher solubility product (K(sp)) than that of the hydrochloride salt. The pH-solubility profiles indicated a pH(max) (pH of maximum solubility) of approximately 5, indicating that the free base would exist as the solid phase above this pH and a salt would be formed below this pH. Below pH 1.5, all solubilities were comparable due to a conversion of haloperidol base or the mesylate salt to the HCl salt form when HCl was used as the acidifying agent. These were confirmed by monitoring the solid phase by differential scanning calorimeter. When their dissolution rates are tested, dissolution rates of the mesylate salt were much higher than those of the free base or the HCl salt, except at very low pH (<2). Dissolution rates of free base and HCl salt also differed from each other, where that of HCl salt exhibits higher dissolution rates at higher pHs. A direct correlation of dissolution rate with solubility at diffusion layer pH at the surface of dissolving solid was established for haloperidol, its hydrochloride, and mesylate salts. CONCLUSIONS: Using pH-solubility and pH-dissolution rate interrelationships, it has been established that diffusion layer pH could be used to explain the observed rank order in dissolution rates for different salt forms. A non-hydrochloride salt, such as a mesylate salt, may provide advantages over a hydrochloride salt due to its high solubility and lack of common ion effect unless at very low pH.

Haloperidol↗
PubMed1989

Determinants of bile secretion: effect of bile salt structure on bile flow and biliary cation secretion.

The effect of five bile salts, deoxycholate, chenodeoxycholate, cholate, ursodeoxycholate, and ursocholate, possessing (in decreasing order) different hydrophobicity, on bile flow and biliary secretion of total calcium, magnesium, sodium, and potassium was studied in 10 patients with T-tubes. Each subject was infused intraduodenally with one or two bile salts, given separately, to produce a selective enrichment of biliary bile salts with the infused bile salt. The choleresis induced per 1-mumol increase of bile salt output was greater during the secretion of 7 beta-hydroxylated bile salts, ursodeoxycholate (0.029 ml), and ursocholate (0.027 ml), followed in decreasing order by deoxycholate (0.023 ml), chenodeoxycholate (0.019 ml), and cholate (0.009 ml). Deoxycholate stimulated the greatest increase in cation secretion per unit increase in bile salt output, followed by chenodeoxycholate and cholate. The two 7 beta-hydroxylated bile salts induced greater cation secretion than did their 7 alpha-epimers. Whereas biliary concentration of divalent cations differed depending on the structure and concentration of the infused bile salt, the concentration of monovalent cations was constant for any species and concentration of infused bile salt. Relationships between bile salt and divalent cation concentration indicate that 1 mumol of secreted biliary deoxycholate, the most hydrophobic bile salt, associates with the greatest amount of calcium (0.046 mumol) and magnesium (0.022 mumol), followed by chenodeoxycholate (0.020 and 0.010 mumol, respectively) and cholate (0.012 and 0.008 mumol, respectively). The capacity of ursodeoxycholate and ursocholate to associate with calcium and magnesium seems to be less than that of their 7 alpha-epimers. These data suggest that of the common bile salts, the more hydrophobic bile salts stimulate bile flow and cation secretion better than the more hydrophilic bile salts, whereas ursodeoxycholate and ursocholate are more effective than their more hydrophobic 7 alpha-epimers. Whereas different bile salts seem to influence the secretion of sodium and potassium mainly by virtue of their choleretic properties, the effect of bile salt structure on biliary secretion of calcium and magnesium suggests the presence of a secretory link that might be consistent with cation-bile salt binding.

Bile↗
PubMed2004

Effect of longer-term modest salt reduction on blood pressure.

BACKGROUND: Many randomised trials assessing the effect of salt reduction on blood pressure show reduction in blood pressure in individuals with high blood pressure. However, there is controversy about the magnitude and the clinical significance of the fall in blood pressure in individuals with normal blood pressure. Several meta-analyses of randomised salt reduction trials have been published in the last few years. However, most of these included trials of very short duration (e.g. 5 days) and included trials with salt loading followed by salt deprivation (e.g. from 20 to 1 g/day) over only a few days. These short-term experiments are not appropriate to inform public health policy which is for a modest reduction in salt intake over a prolonged period of time. A meta-analysis by Hooper et al is an important attempt to look at whether advice to achieve a long-term salt reduction (i.e. more than 6 months) in randomised trials causes a fall in blood pressure. However, most trials included in this meta-analysis achieved a small reduction in salt intake; on average, salt intake was reduced by 2 g/day. It is, therefore, not surprising that this analysis showed a small fall in blood pressure, and that a dose-response to salt reduction was not demonstrable. OBJECTIVES: To assess the effect of the currently recommended modest reduction in salt intake (WHO 2003; SACN 2003; Whelton 2002), on blood pressure in individuals with normal and elevated blood pressure. To assess whether the magnitude of the reduction in blood pressure is dependent on the magnitude of the reduction in salt intake. SEARCH STRATEGY: We searched MEDLINE, EMBASE, Cochrane library, CINAHL, and reference list of original and review articles. SELECTION CRITERIA: We included randomised trials with a modest reduction in salt intake and a duration of 4 or more weeks. DATA COLLECTION AND ANALYSIS: Data were extracted independently by two persons. Mean effect sizes were calculated using both fixed and random effect models using Review Manager 4.2.1 software. Weighted linear regression was used to examine the relationship between the change in urinary sodium and the change in blood pressure. We used funnel plots to detect publication and other biases in the meta-analysis. MAIN RESULTS: Seventeen trials in individuals with elevated blood pressure (n=734) and 11 trials in individuals with normal blood pressure (n=2220) were included. In individuals with elevated blood pressure the median reduction in 24-h urinary sodium excretion was 78 mmol (4.6 g/day of salt), the mean reduction in systolic blood pressure was -4.97 mmHg (95%CI:-5.76 to -4.18), and the mean reduction in diastolic blood pressure was -2.74 mmHg (95% CI:-3.22 to -2.26). In individuals with normal blood pressure the median reduction in 24-h urinary sodium excretion was 74 mmol (4.4 g/day of salt), the mean reduction in systolic blood pressure was -2.03 mmHg (95% CI: -2.56 to -1.50) mmHg, and the mean reduction in diastolic blood pressure was -0.99 mmHg (-1.40 to -0.57). Weighted linear regression analyses showed a correlation between the reduction in urinary sodium and the reduction in blood pressure. REVIEWERS' CONCLUSIONS: Our meta-analysis demonstrates that a modest reduction in salt intake for a duration of 4 or more weeks has a significant and, from a population viewpoint, important effect on blood pressure in both individuals with normal and elevated blood pressure. These results support other evidence suggesting that a modest and long-term reduction in population salt intake could reduce strokes, heart attacks, and heart failure. Furthermore, our meta-analysis demonstrates a correlation between the magnitude of salt reduction and the magnitude of blood pressure reduction. Within the daily intake range of 3 to 12 g/day, the lower the salt intake achieved, the lower the blood pressure.

Aldosterone↗
PubMed1996

The Effects of Salts on the Lower Consolute Boundary of a Nonionic Micellar Solution

A molecular model based in statistical thermodynamics is used to study salt effects on the lower consolute boundary of the aqueous non-ionic surfactant C8E5. The C8E5 micelles are modeled as hard spheres interacting via a temperature-dependent Yukawa attraction and the salt ions are modeled as positively and negatively charged hard spheres interacting via a Coulombic potential. The excess thermodynamic properties due to the Coulombic and Yukawa potentials are evaluated using the analytical solutions to the Ornstein-Zernike equation obtained for the mean spherical approximation closure. The Yukawa parameters for the micelle-micelle attractions are determined by fitting the theoretical phase diagram for a pure Yukawa fluid to the experimental lower consolute boundary for a salt-free C8E5 micelle-water solution. Ion-solvent interactions are indirectly accounted for by using previously determined adjusted values for the cation size and the dielectric constant of the medium. We evaluate theoretical coexistence curves for the C8E5 micelle-salt-water mixtures in the temperature-micelle volume fraction and temperature-salt molarity planes. We calculate the changes in the lower critical solution temperature (LCST) for the C8E5 micelle-salt-water mixture as a function of salt concentration for the salts NaF, NaCl, NaBr, NaI, and Na2SO4 and compare the trends seen with experiments. When ion-solvent interactions are indirectly accounted for, the theory correctly predicts the salting-out trends exhibited by NaF, NaCl, and NaBr. For the 1:2 salt (Na2SO4), charge effects resulting from the higher charge on the ions play a more important role in salting-out than ion-solvent interactions do. The theory, however, cannot predict the salting-in phenomena exhibited by NaI, thus indicating that salting-in is the result of variations in the intermicellar attraction as a function of the salt type and salt concentration. The theoretical results also indicate that excluded-volume forces resulting from the different sizes of the salt ions cannot alone account for the salting-in and salting-out phenomena seen in aqueous nonionic micellar solutions.

Journal Article↗
PubMed1998

Influence of dietary salts on the cardiovascular effects of low-dose combination of ramipril and felodipine in spontaneously hypertensive rats.

1 In spontaneously hypertensive rat (SHR) we examined over a 4-week period the influence of control low sodium diet, common salt-enriched diet (sodium chloride 6% of the dry weight of the chow) and a novel mineral salt-enriched diet (potassium-, magnesium-, and l-lysine-enriched mineral salt added at a 75% higher level of 10.5% to produce the same sodium chloride concentration of 6%) on the cardiovascular effects produced by a low-dose combination of an angiotensin converting enzyme inhibitor ramipril (0.25 mg kg(-1) day(-1) in the food) and a calcium channel blocker felodipine (0.4 mg kg(-1) day(-1) subcutaneously via an osmotic minipump). 2 Common salt, but not the mineral salt, accelerated the development of hypertension and induced left ventricular and renal hypertrophy in SHR. Neither common salt nor mineral salt significantly affected heart rate. 3 The combination of ramipril and felodipine decreased systolic blood pressure and prevented the development of left ventricular hypertrophy effectively during the common salt diet without any significant effect on the heart rate. The cardiovascular effects of the drug combination were improved by the low sodium diet or by replacement of high common salt in the diet by mineral salt. 4 Responses of endothelium-intact mesenteric arterial rings in vitro were examined at the end of the four-week study. The combination of ramipril and felodipine markedly improved the endothelium-dependent vascular relaxation responses to acetylcholine and enhanced the endothelium-independent vascular relaxation responses to sodium nitroprusside in SHR on control and common salt diets. Replacement of common salt in the diet by mineral salt improved the endothelium-dependent vascular relaxation responses to acetylcholine. The drug combination attenuated the alpha-adrenoceptor-mediated vascular contractile responses to noradrenaline during the common salt diet. 5 Ramipril and felodipine in combination increased plasma renin activity by 1.9-3.2 fold without affecting serum aldosterone levels. 6 Our findings suggest that the cardiovascular effect of the low-dose combination of ramipril and felodipine was maintained during high salt intake. However, salt restriction or replacement of common salt in the diet by the potassium- and magnesium-enriched mineral salt improved the cardiovascular effects of the drug combination. In the face of a high intake of sodium, a part of the beneficial cardiovascular effects of the drug combination is apparently mediated by improved endothelium-dependent and endothelium-independent vascular relaxation responses and attenuated alpha-adrenoceptor-mediated vascular contractile responses.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

The lack of a modulating effect of non-genetic factors (age, gonads and maternal environment) on the phenotypic expression of the salt-susceptibility genes in the Sabra rat model of hypertension.

OBJECTIVE: This study was designed to test the hypothesis that non-genetic factors such as age, gonads and maternal environment modulate the expression of the salt-susceptibility genes and affect the blood pressure response to salt-loading (salt-sensitivity and salt-resistance) in the Sabra rat model of hypertension. METHODS: The blood pressure response to salt-loading was studied in Sabra hypertension prone (SBH/y) and Sabra hypertension resistant (SBN/y) rats of both sexes: (1) at 1, 3, 6, 9 and 12 months of age, (2) in adult rats after orchiectomy or oophorectomy, and (3) in animals that had been raised and nourished from birth to weaning by a foster mother from the contrasting strain. In each of the study protocols, systolic blood pressure was measured at baseline by the tail cuff method, animals were salt-loaded with deoxycorticosterone acetate, and blood pressure was measured again after 4 weeks. RESULTS: Basal blood pressure at all the ages studied and in both sexes was on average 10-15 mmHg higher in SBH/y than in SBN/y. Salt-loading in SBN/y of both sexes aged 1-12 months did not induce any significant increment in blood pressure. Salt-loading in SBH/y, in contrast, caused a highly significant rise in systolic blood pressure, of 40 mmHg or more at all the ages studied. There was no age difference or sex dependence in the magnitude of the blood pressure response to salt Oophorectomy or orchiectomy did not affect the levels of basal blood pressure nor prevent the hypertensive response to salt-loading in SBH/y or the lack of a hypertensive response in SBN/y rats. Gonadectomy did not affect blood pressure in salt-loaded hypertensive SBH/y nor in salt-loaded normotensive SBN/y. The basal blood pressure and the blood pressure responses of SBH/y and SBN/y of both sexes raised by foster mothers of the contrasting strains from birth to weaning were not different from those observed when raised by their natural mothers. CONCLUSIONS: This study indicates that salt-sensitivity in SBH/y and salt-resistance in SBN/y are not age-dependent phenomena; that the magnitude of the BP response to salt-loading is not sex-dependent; and that neither gonadectomy nor the maternal environment affect the blood pressure response to salt-loading in the adult animal of either strain. These non-genetic factors thus do not modulate expression of the salt-susceptibility genes in the Sabra genetic model of salt-sensitive hypertension.

Age Factors↗
PubMed1989

Alpha-adrenoceptor properties in rat strains sensitive or resistant to salt-induced hypertension.

Cerebral and renal alpha 2-adrenoceptors are implicated in the control of sympathetic activity and of sodium reabsorption respectively. In addition, sodium ions play an important role in the regulation of either alpha 2-adrenoceptor densities and affinities for adrenergic agonists. In the present study, alpha-adrenoceptor properties were investigated in genetically predetermined salt-sensitive and salt-resistant Dahl and Sabra rats. Cerebral alpha 2-adrenoceptor densities were higher in salt-resistant than in salt-sensitive Dahl and Sabra rats. In contrast, renal alpha 2-adrenoceptor density was higher in salt-sensitive than in salt-resistant rats. No difference in cerebral and renal alpha 1-adrenoceptor densities was observed between Dahl and Sabra substrains. Noradrenaline content in cerebral and renal cortex were also similar in both these rat substrains. Sodium ions markedly increased cerebral and renal high-affinity alpha 2-adrenoceptor densities in salt-sensitive but not in salt-resistant rats. Cerebral and renal alpha 1-adrenoceptor densities were unchanged in salt-sensitive and salt-resistant substrains of Dahl and Sabra rats. In addition, sodium ions reduced the affinity of adrenaline for renal alpha 2-adrenoceptors in salt-sensitive rats but not in salt-resistant rats. We can conclude that there exist genetically determined differences in the densities and properties of cerebral and renal alpha 2-adrenoceptors between salt-sensitive and salt-resistant rat strains. Abnormal densities of alpha 2-adrenoceptors may play a primary role in the role in the development of hypertension in salt-sensitive animals. These results also suggest an association between absence of sodium regulation of alpha 2-adrenoceptors and resistance to salt-induced hypertension. The absence of sodium regulation in salt-resistant rats may be linked either to a particular receptor conformation or to an abnormal structure of the receptor system. This property may represent a genetically-mediated change responsible for the resistance to the development of salt-induced hypertension.

Animals↗
PubMed1984

Venous responses to salt loading in hypertensive subjects.

It has been previously suggested that salt loading produces structural changes of the arteries in hypertensive patients who respond to salt loading with a greater rise of blood pressure. This study examined the possibility that salt loading alters venous distensibility in hypertensive patients. Twenty-one patients with essential hypertension were placed on a low-sodium diet (70 meq) for 7 days and then were placed on a high-sodium diet (345 meq) for 7 days. Patients were arbitrarily divided into two groups based on the response of their blood pressure to salt loading: (1) those whose mean blood pressure increased by more than 10% while on the high-salt diet as compared with those on the low-salt diet (salt-responsive patients, n = 8) and (2) those whose mean blood pressure did not increase by more than 10% (salt-nonresponsive patients, n = 13). The venous pressure-volume relationship was determined in the forearm with a water-filled plethysmograph when patients were on the low- and high-salt diet. Venous pressure-volume curves were not different between salt-responsive and salt-nonresponsive patients while on the low-salt diet. High-salt intake shifted the curve toward the pressure axis for salt-responsive patients (p less than .05) but not for salt-nonresponsive patients. Phentolamine, 1 mg administered intravenously for 5 min, did not significantly alter venous pressure-volume curves for either group while on the low- or high-salt diet. These results suggest that salt loading decreased venous distensibility in salt-responsive patients, which resulted from nonadrenergic mechanisms: structural changes of the veins could perhaps be included as one of these mechanisms.

Adult↗
PubMed1992

Impaired renal vascular reactivity in prehypertensive Dahl salt-sensitive rats.

We have previously shown that renal vascular resistance is less in Dahl salt-sensitive rats than salt-resistant rats fed 1% NaCl diets; however, renal vascular resistance increases before nonrenal vascular resistance as salt-sensitive rats develop hypertension when fed 8% NaCl diets. When salt-resistant rats are given 8% NaCl diets, renal vascular resistance decreases. The current study reports effects of atrial natriuretic peptide, nitroprusside, norepinephrine, angiotensin II, and endothelin-1 on renal and nonrenal vascular resistance in prehypertensive salt-sensitive and salt-resistant rats given 1% NaCl diets; doses used did not affect blood pressure. Resistance of nonrenal vessels in salt-sensitive and salt-resistant rats responded similarly to dilators or constrictors. However, atrial natriuretic peptide and nitroprusside decreased renal vascular resistance of salt-resistant rats (by 65%, p less than 0.01) but not that of salt-sensitive rats. Norepinephrine, angiotensin II, and endothelin-1 increased renal vascular resistance in salt-sensitive rats by 126%, 135%, and 135%, respectively (p less than 0.01); norepinephrine and angiotensin II did not change renal vascular resistance of salt-resistant rats, but endothelin-1 decreased renal vascular resistance in salt-resistant rats by 30% (p less than 0.01). Reactivity of nonrenal blood vessels in prehypertensive salt-sensitive and salt-resistant rats was similar when infused with dilators or constrictors in doses used. By contrast, renal vessels of salt-sensitive rats did not dilate in response to atrial natriuretic peptide and nitroprusside but were hypersensitive to norepinephrine and angiotensin II. Endothelin-1 caused renal vasoconstriction in salt-sensitive rats and renal vasodilation in salt-resistant rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1994

Salt sensitivity in hypertension. Renal and cardiovascular implications.

The mechanisms responsible for the increase in blood pressure response to high salt intake in salt-sensitive patients with essential hypertension are complex and only partially understood. A complex interaction between neuroendocrine factors and the kidney may underlie the propensity for such patients to retain salt and develop salt-dependent hypertension. The possible role of vasodilator and natriuretic agents, such as the prostaglandins, endothelium-derived relaxing factor, atrial natriuretic factor, and kinin-kallikrein system, requires further investigation. An association between salt sensitivity and a greater propensity to develop renal failure has been described in certain groups of hypertensive patients, such as blacks, the elderly, and those with diabetes mellitus. Salt-sensitive patients with essential hypertension manifest a deranged renal hemodynamic adaptation to a high dietary salt intake. During a low salt diet, salt-sensitive and salt-resistant patients have similar mean arterial pressure, glomerular filtration rate, effective renal plasma flow, and filtration fraction. On the other hand, during a high salt intake glomerular filtration rate does not change in either group, and effective renal blood flow increases in salt-resistant but decreases in salt-sensitive patients; filtration fraction and glomerular capillary pressure decrease in salt-resistant but increase in salt-sensitive patients. Salt-sensitive patients are also more likely than salt-resistant patients to manifest left ventricular hypertrophy, microalbuminuria, and metabolic abnormalities that may predispose them to cardiovascular diseases. In conclusion, salt sensitivity in hypertension is associated with substantial renal, hemodynamic, and metabolic abnormalities that may enhance the risk of cardiovascular and renal morbidity.

Blood Pressure↗
PubMed1996

Impaired renal vasodilation and urinary cGMP excretion in Dahl salt-sensitive rats.

We previously have shown that Dahl salt-sensitive rats increase renal vascular resistance in response to excessive salt feeding before total peripheral resistance increases and hypertension occurs. Failure of renal vasculature to dilate, as normally occurs in Dahl salt-resistant rats fed a high salt diet, may play a role in the development of hypertension in Dahl salt-sensitive rats. We also showed that renal vasculature in salt-sensitive rats is hyperreactive to vasoconstrictors and hyporeactive to vasodilators. Atrial natriuretic peptide, by stimulating cell-bound receptors, and nitroprusside, by generating nitric oxide, cause renal vasodilation by generating cGMP. Studies were undertaken to determine whether defective renal vasodilation in Dahl salt-sensitive rats is due to impaired production of cGMP. We examined the influence of nitroprusside infusion and salt intake on renal vascular resistance and cGMP excretion in salt-sensitive rats. Results demonstrate that salt feeding and nitroprusside infusion increase cGMP excretion and decrease renal vascular resistance in salt-resistant rats (P < .01), and, although this relationship was less clear in salt-sensitive rats, there was a reciprocal relationship between renal vascular resistance and cGMP excretion in all animals studied. Salt feeding and nitroprusside infusion caused less of an increase in cGMP excretion in salt-sensitive than in salt-resistant rats (P < .01). In conclusion, these studies support the concept that impairment in cGMP generation may play a primary role in the inability of the kidneys of Dahl salt-sensitive rats to vasodilate in response to increased salt intake. Such an impairment could contribute to salt retention and the development of hypertension.

Animals↗
PubMed2005

[Study on the national program of monltoring the iodized-salt situation in 2004].

OBJECTIVE: To understand the situation of quality and consumption of iodized-salt at production and household levels through monitoring on salt. METHODS: 9 townships were chosen in each county at different locations. In each township, two villages were selected in the center of the township and another two villages in remote settings. In each village, 8 households were selected for salt collection. The iodine concentrations in salt (except some special kinds of salt) were detected by method of direct titration with criteria in GB/T 13025.7-1999, in which the iodine content in qualified iodized-salt was set as 20 to 50 mg/kg and that in non-iodized-salt it was below 5 mg/kg. RESULTS: Except for Tibet and Xinjiang, lot qualified rate of production level was 97.39% at the national level. Except for Xinjiang, the qualified rate of iodized-salt of household level was 96.45%; qualified iodized-salt coverage rate was 93.47%; noniodized-salt coverage rate was 3.09%. The results of the iodized-salt monitoring in 2004 maintained almost the same level as that in 2002. At production level,lot qualified rate of iodized-salt in Sichuan and Qinghai provinces were below 90%. At household level the qualified rate of iodized-salt in Sichuan and Hainan were below 90%. The coverage rates of qualified iodized-salt were below 90% for the total 7 provinces. In 5 provinces, the non-iodized-salt coverage rates were above 10%. CONCLUSIONS: At national level the qualification of iodized-salt at production level was satisfactory. The coverage rates of qualified iodized-salt were below 90% not only in western but in some eastern provinces(including Beijing), which indicated that importance should be attached to the western areas and some newly discovered areas with problems as well. Through continual improvement of qualified iodized-salt coverage, sustained IDD elimination will be achieved.

China↗
PubMed1991

Neuroendocrine factors in salt appetite.

We dedicate this paper to Curt P. Richter, father of the study of salt appetite, who died recently at the age of 94. Richter first demonstrated that the adrenalectomized rat's voracious appetite for salt kept it alive (1936) and showed the same in humans (1940). Our first paper in 1955 demonstrated that salt appetite was an innate response to salt depletion. Since then, we have pursued the notion that the neuroendocrine consequences of sodium depletion create a brain state that raises salt appetite. In Epstein's laboratory, it was shown that angiotensin and aldosterone, the hormones of salt retention in the periphery, act synergistically in the brain to produce salt appetite in the rat. Block either hormone and the appetite is reduced by half; block both and the appetite is eliminated despite severe bodily need. With repeated depletions or treatments of the brain with angiotensin and aldosterone, salt ingestion increases, reaching an asymptote by the third depletion. Need-free intake of NaCl also increases, especially in female rats which ingest more NaCl than male rats. In Stellar's laboratory, running speed to salt solutions in a runway is used as a measure of salt appetite. When the appetite is raised with large doses of DOCA, a mimic of aldosterone, rats run rapidly for a taste of strong salt solutions as high as 24% (almost 4 molar). Using ingestion as a measure, the role of the atrial natriuretic peptide (ANP), an antagonist of angiotensin's physiological effect, was investigated as a modulator of salt appetite. When angiotensin is involved is producing salt appetite, following sodium depletion by a diuretic combined with a low-salt diet, ANP reduced salt intake by 40%. When salt appetite was raised by DOCA, however, ANP either had no effect or reduced salt ingestion by only 10%. The subfornical organ, the lateral preoptic area, and the central and medial nuclei of the amygdala are being investigated as major components of the limbic circuit underlying salt appetite produced by the actions of angiotensin, aldosterone and ANP in the brain.

Animals↗
PubMed1996

[Evaluation of potassium iodide in Polish dietary salt].

The consequences of iodine deficiency occurring still in Poland include serious health disorders in the population, such as psycho- somatic retardation, hypothyroidism, endemic goitre, even cretinism. Administration of iodized edible salt with daily diet is an effective method for prevention of iodine deficiency. The condition of success is the proper level of potassium iodide in this salt and adequate distribution of iodized salt in various regions of the country. Successful iodine prophylaxis should be based on iodination of edible salt in amounts of 30 +/- 10 mg of KJ/kg. The permission given in the period from February to May 1994 by the General Sanitary Inspector for the production and marketing of edible salt iodized in proportions of 30 +/- 10 mg KJ/kg opened the possibility of starting its production in salt mines. The purpose of the presently reported work was to assess, in cooperation with the Province Sanitary Epidemiological Stations, the adequacy of iodination of the Polish edible salt produced in the years 1994-1995. The study was carried out according to the Polish Standard "Salt (Sodium Chloride) /PN-80/C-84081.35. Potassium iodide determination by photo colorimetric method." In 1995 the number of edible salt samples analyzed was 2484, and this number included 2129 samples of iodized salt. Potassium iodide content agreeing with the above permission was found in 122 samples, that is in 57.4% of iodized salt samples. In 603 samples (28.3%) of iodized salt this content was below that given in the permissions. In 1994 this study was carried out taking 2172 samples of edible salt, including 1586 samples of iodized salt. The content of potassium iodide agreeing with the permissions (30 +/- 10 mg/kg) was found in 342 samples (28, 1%), but 272 (22.4%) samples of iodized salt produced by salt mines contained lower amounts of potassium iodide than the amount indicated in the permissions, but still within the limits set down in the Polish Standard (20 +/- 5 mg/kg). The obtained results (57.4%) indicate an improvement of the process of salt iodination as compared with the results obtained in 1992 and 1993 (38.3%) and 1994 (28.1%). However, varying amounts of potassium iodide differing from the accepted values were found in salt declared as iodized.

Goiter, Endemic↗
PubMed1998

Effect of salt-loading on blood pressure, insulin sensitivity and limb blood flow in normal subjects.

1. The aim of this study was to determine the effects of high (220 mmol/day) and low (40 mmol/day) salt intake for 6 days on blood pressure, leg blood flow and insulin sensitivity in 18 healthy normotensive subjects. 2. Twenty-four-hour ambulatory blood pressure was measured at baseline, during salt-loading and salt-depletion. Insulin sensitivity was determined by a two-step euglycaemic-hyperinsulinaemic clamp (low and high insulin infusion rates: 40 and 600 m-unit.min-1.m-2 respectively) and leg blood flow by plethysmography. 3. Salt-loading resulted in changes in weight [change between salt-loading and salt-restriction: delta=+0.45 (S.D. +/-0.69) kg, P=0.015], plasma renin [delta=-11.5 (S.D.+/-12.9) micro-units/l, P=0.001] and urinary noradrenaline [delta=-8.6 (S.D. +/-18.7) nmol/mmol creatinine, P=0.05]. There were borderline significant increases in 24-h systolic blood pressure [delta=+5.8 (S. D.+/-14.2) mmHg, P=0.06] and plasma volume [delta=+0.29 (S.D.+/-0. 67) litres, P=0.08]. 4. Insulin sensitivity was similar in both salt states. Geometric mean metabolic clearance rate of low-dose insulin: low salt, 5.13 (S.D.x//1.35) dl/min; high salt, 4.94 (S.D.x//1.37) dl/min, P=1.0. Geometric mean metabolic clearance rate of high-dose insulin: low salt, 9.68 dl/min (S.D.x//1.30); high salt, 9.68 (S.D. x//1.27) dl/min, P=0.69. 5. Leg blood flow response to high-dose insulin on high salt increased significantly compared with low salt. Percentage change of blood flow on low salt, delta=+36.6 (S.D.+/-22. 9)% versus high salt, delta=+66.8 (S.D.+/-52.2)%, P=0.03. 6. There were no significant relationships between salt-related changes in limb blood flow and changes in insulin sensitivity at either insulin infusion rate. 7. We conclude that salt-loading, despite changing body weight, the renin-angiotensin-aldosterone system, urinary noradrenaline and the leg blood flow response to insulin, has no significant effect on insulin sensitivity. Salt-loading causes dissociated effects on insulin-induced vasodilatation and glucose disposal.

Aldosterone↗
PubMed1995

Molecular mechanisms of hepatic bile salt transport from sinusoidal blood into bile.

An increasingly complex picture has emerged in recent years regarding the bile salt transport polarity of hepatocytes. At the sinusoidal (or basolateral) plasma membrane two bile salt-transporting polypeptides have been cloned. The Na(+)-taurocholate-cotransporting polypeptide (Ntcp) can account for most, if not all, physiological properties of the Na(+)-dependent bile salt uptake function in mammalian hepatocytes. The cloned organic anion-transporting protein (Oatp1) can mediate Na(+)-independent transport of bile salts, sulfobromophthalein, estrogen conjugates, and a variety of other amphipathic cholephilic compounds. Hence, Oatp1 appears to correspond to the previously suggested basolateral multispecific bile sale transporter. Intracellular bile salt transport can be mediated by different pathways. Under basal bile salt flux conditions, conjugated trihydroxy bile salts bind to cytoplasmic binding proteins and reach the canalicular plasma membrane predominantly via cytoplasmic diffusion. More hydrophobic mono- and dihydroxy and high concentrations of trihydroxy bile salts associate with intracellular membrane-bound compartments, including transcytotic vesicles, endoplasmic reticulum (ER), and Golgi complex. A facilitated bile salt diffusion pathway has been demonstrated in the ER. The exact role of these and other (e.g., lysosomes, "tubulovesicular structures") organelles in overall vectorial transport of bile salts across hepatocytes is not yet known. Canalicular bile salt secretion is mediated by two ATP-dependent transport systems, one for monovalent bile salts and the second for divalent sulfated or glucuronidated bile salt conjugates. The latter is identical with the canalicular multispecific organic anion transporter, which also transports other divalent organic anions, such as glutathione S-conjugates. Potential dependent canalicular bile salt secretion has also been suggested to occur, but its exact mechanism and physiological significance remain unclear, since a potential driven bile salt uptake system has also been identified in the ER. Hypothetically, and similar to changes in cell volume, the intracellular potential could also play a role in the regulation of the number of bile salt carriers at the canalicular membrane and thereby indirectly influence the maximal canalicular bile salt transport capacity of hepatocytes.

Animals↗