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Biomedical subjects

K Ando

Publications and source records attributed to K Ando.

At least 487 records · Page 27Linked to original sources
PubMed1990

Salt sensitivity in hypertensive rats with angiotensin II administration.

We examined the salt sensitivity of blood pressure in angiotensin II (ANG II)-induced hypertension. Wistar rats, salt loaded (0.66, 2, or 8% salt-containing diet) for 4 or 12 days, were infused intravenously with 15 or 60 ng/min of ANG II. Systolic blood pressure (SBP) was not increased by long-term (12 days) salt loading, and SBP was unchanged with ANG II and normal-salt (0.66%) diet. However, when combined with salt loading, ANG II produced hypertension in a dose-dependent fashion; compared with control (120 +/- 2 mmHg), SBP was increased with 15 ng/min of ANG II and 8% salt diet (145 +/- 5 mmHg, P less than 0.05) and with 60 ng/min of ANG II and either 2 or 8% salt diet (149 +/- 8 and 174 +/- 8 mmHg, P less than 0.05, respectively). Na space (exchangeable Na) was increased in a roughly similar pattern and correlated significantly (r = 0.531, P less than 0.05) with SBP. However, with 15 ng/min of ANG II, Na space was not different among rats on either level of salt loading, although the 8% salt diet elevated SBP. Data obtained with short-term (4 days) treatment indicate that an elevated Na space preceded development of hypertension. With 15 ng/min of ANG II and 8% salt diet for 4 days, Na space was markedly (P less than 0.05) increased, but SBP was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1990

Attenuated vasodilator responses to Mg2+ in young patients with borderline hypertension.

Limb vascular responses to magnesium (Mg2+) and potassium (K+) ions were studied in 19 young patients with borderline hypertension (BHT) and compared with those of 22 age-matched normotensive subjects (NT) by measuring the forearm blood flow response to intra-arterial infusion of magnesium sulfate and potassium chloride using venous occlusion plethysmography. Percent decrements of forearm vascular resistance with Mg2+ infusions were significantly less in BHT subjects than in NT (-37.2 +/- 4.2% versus -53.0 +/- 2.0%, p less than 0.05, during the infusion of 0.1 meq Mg2+/min, and -52.2 +/- 4.3% versus -65.6 +/- 1.5%, p less than 0.05, during the infusion of 0.2 meq Mg2+/min). Moreover, the relation of the magnitude of Mg2+ response to initial vascular resistance in six of 10 BHT subjects lies above the 95% confidence interval for predicted values calculated for response points in 11 NT subjects, suggesting attenuated vasodilator responses of Mg2+ in a significant proportion of BHT subjects. In contrast, the response points to K+ in eight of nine BHT subjects fall within the 95% confidence interval, suggesting normal vasodilator responses to K+ in the majority of BHT subjects. Furthermore, the effect of small increments in local serum calcium concentrations on Mg2(+)- and K(+)-induced vasodilation was studied in normal volunteers. Isosmolar CaCl2 solution infused into the same brachial artery at a rate of 0.09 meq/min severely blunted the vasodilating actions of Mg2+ (-30.1 +/- 6.5% versus -65.8 +/- 3.2%, p less than 0.01, during the infusion of 0.2 meq Mg2+/min) but did not affect those of K+ (-63.1 +/- 3.1% versus -55.9 +/- 3.8%, NS, during the infusion of 0.154 meq K+/min). It appears that Mg2(+)-induced vasodilation should be due to the antagonistic action of Mg2+ to calcium, but K(+)-induced vasodilation might not be directly related to calcium movement. Thus, these attenuated responses to Mg2+ but normal responses to K+ in BHT subjects may indicate an underlying defect in vascular Mg2+ metabolism, which ultimately may be related to the alterations in calcium handling by plasma membranes rather than to the abnormalities of membrane Na(+)-K+ pump activity.

Adult↗
PubMed1990

Plasma endothelin levels in hypertension and chronic renal failure.

Endothelin-1 is a novel endothelium-derived vasoconstrictive peptide. Using a highly specific and sensitive radioimmunoassay for endothelin-1, plasma levels of immunoreactive endothelin-1 were measured in 32 research subjects with normal renal function (21 normal subjects and 11 patients with essential hypertension), 24 patients with nondialyzed chronic renal failure, and 51 patients undergoing maintenance hemodialysis. Although there was no significant difference in plasma immunoreactive endothelin-1 levels among the three groups, patients with essential hypertension had significantly higher plasma endothelin-1 levels than normal subjects (2.29 +/- 1.09 vs. 1.41 +/- 0.50 pg/ml, p less than 0.025). When nondialyzed and hemodialyzed patients were divided into hypertensive and normotensive groups, the nondialyzed hypertensive group (n = 17) had higher plasma endothelin-1 levels than the comparable normotensive group (n = 7) (3.08 +/- 3.43 vs. 0.73 +/- 0.34 pg/ml, p less than 0.05), and the hemodialyzed hypertensive group (n = 18) had higher plasma endothelin-1 levels than the comparable normotensive group (n = 33) (2.66 +/- 1.92 vs. 1.35 +/- 0.73 pg/ml, p less than 0.005). Plasma atrial natriuretic factor, arginine vasopressin, renin activity, and aldosterone concentration did not show significant differences between hypertensive and normotensive individuals or a correlation with plasma endothelin-1 levels. These data suggest that circulating endothelin-1 may be partly involved in the development or maintenance of hypertension in humans.

Endothelins↗
PubMed1990

Systemic and regional hemodynamics in patients with salt-sensitive hypertension.

Twenty-two patients with normal plasma renin and essential hypertension were classified as "salt-sensitive" (SS) (n = 9) or "non-salt-sensitive" (NSS) (n = 13) from an increase in mean blood pressure with changes in sodium intake from 25 to 250 meq/day. With the high sodium diet, the SS patients gained more weight (p less than 0.05), retained more sodium (p less than 0.05), and had a greater increase in cardiac output (p less than 0.05). Despite the markedly increased cardiac output, systemic vascular resistance did not change with sodium loads in the SS patients, whereas the NSS patients had a significant decrease in systemic vascular resistance. Thus, the greater increase in blood pressure with sodium loads in SS patients can be attributed not only to an increase in cardiac output, possibly resulting from greater sodium retention, but also to inappropriately elevated systemic vascular resistance. Concomitant with a greater increase in cardiac output, the SS patients had a greater increase in forearm blood flow with sodium loading than the NSS patients (p less than 0.02). In contrast, blood flow to the kidney and the liver was not significantly changed in either group; renal (p less than 0.05) and hepatic (p less than 0.01) vascular resistance increased significantly in SS patients but remained unchanged in NSS patients. Thus, evidence presented suggests that the greater increase in blood pressure with sodium loads seems to be characterized by a very inhomogenous distribution of local flow and resistance in SS patients; renal and hepatic blood flow remains essentially unchanged and skeletal muscle blood flow receives almost all of the increase in cardiac output. Moreover, systemic vascular resistance changes did not reflect the resistance of individual beds because vasoconstriction appeared in the kidney and the splanchnic area but was masked by prominent vasodilation in the skeletal muscle. Because this hemodynamic pattern is similar to the pattern evoked during defense reaction, it is suggested that sympathetic overactivity on a selective basis might be involved in the impaired renal function for sodium excretion and the increase in blood pressure with sodium loads in SS patients.

Blood Pressure↗
PubMed1990

Circulating forms of human atrial natriuretic peptide in patients with congestive heart failure.

To elucidate the circulating forms of human atrial natriuretic peptide (hANP) in patients with congestive heart failure (CHF), plasma samples obtained from 36 patients with CHF were analyzed and compared with those from normal subjects. Plasma concentrations of hANP-like immunoreactivity (LI) from normal subjects and patients with mild CHF (class I), as classified by the New York Heart Association (NYHA) functional criteria, did not differ (15 +/- 1 vs. 16 +/- 1 pmol/L, mean +/- SE), whereas plasma levels of hANP-LI in patients with moderate and severe CHF significantly (P less than 0.01) increased in relation to the severity of CHF (class II, 44 +/- 4 pmol/L; class III, 116 +/- 24 pmol/L; class IV, 141 +/- 21 pmol/L). Reverse-phase HPLC and gel permeation chromatography coupled with RIA for hANP revealed that the circulating forms of hANP-LI consisted of alpha-hANP, beta-hANP, and gamma-hANP in CHF, whereas alpha-hANP predominated in normal plasma. The percentage of beta-hANP in total hANP-LI as calculated from the chromatograms by gel filtration was greater in severe CHF (NYHA class III and IV) than those in mild CHF (NYHA class I and II), and apparently exceeded those of other forms. Successful medical treatment for CHF resulted in a marked reduction of total plasma hANP-LI levels with a concomitant disappearance or reduction of beta-hANP in 14 patients examined. These data suggest that beta-hANP and gamma-hANP are secreted from the failing human heart, possibly resulting from the augmented synthesis and/or the altered processing of hANP precursor in cardiocytes, and that circulating beta-hANP may serve as a potential marker for the severity of CHF in man.

Adult↗
PubMed1990

[Assessment of drug effects on memory by delayed discrimination responses in rats].

Delayed discrimination experiments were conducted to examine drug effects on memory in rats. Three kinds of experimental situations: a Y-maze, an operant chamber with two retractable levers, and an operant chamber with two fixed levers were used. A discriminative stimulus light either on the left or the right side of a stimulus panel was presented for a brief period in each situation. After a certain delay time following extinguishment of the light, a choice response to the previously lighted side was termed as a correct choice. Scopolamine at 0.015-0.06 mg/kg, s.c., decreased the correct choice ratio in trials with a delay time of 0 sec in the Y-maze situation and in trials with longer delay times in the operant chamber situations. Nicotine at 0.06-1 mg/kg, s.c., decreased the correct choice ratio in trials with a delay time of 0-4 sec in the Y-maze situation, a delay time of 4 sec in the retractable-lever operant chamber situation, and a delay time of 0.1 sec in the fixed-lever operant chamber situation. Using this delayed discrimination procedure, drug effects on the relationship between delay time and correct choice ratio were observed. From these results, the present procedure was found to be useful for the evaluation of drug effects on memory in rats.

Animals↗
PubMed1990

[Study on ear burn model in mice and its significant application].

The experimental ear burn model in mice was developed in order to research the wound surface on a burn injury biochemically, and the following results were obtained: 1) The ear weight tended to increase up to 3 hr after preparation of the burn and then decreased subsequently. 2) Significant increase in leakage of Evans blue (EB) dye into the ear was observed in the burn group as compared to the non-burnt group. The amount of EB dye leaked per ear became the maximum in 3 hr which was similar to the increase in ear weight. 3) Correlation between the ear weight after burn and the amount of EB dye leaked into the ear on the burned site was observed up to 6 hr after preparation of the burn. 4) Vasopermeability of the ear was depressed with antihistamine treatment, but non-steroidal anti-inflammatory drugs had no effect. The ear weight of glucocorticoid-treated mice tended to be decreased as compared with the weight of the burned ear. 5) The histamine contents in the burned ear did not change, but the bradykinin contents significantly increased after the burn.

Animals↗
PubMed1990

Phasic plasma atrial natriuretic polypeptide changes in DOCA-salt hypertensive rats.

We determined plasma and cardiac immunoreactive atrial natriuretic polypeptide (ir-ANP) levels in rats treated with deoxycorticosterone acetate (DOCA) and sodium chloride for 1, 7, and 28 days. Systolic blood pressure of DOCA-salt rats began to increase from the 7th day and reached 191 +/- 7 mmHg at the 28th day. One day after treatment with DOCA-salt, plasma levels of ir-ANP were increased compared to that of control rats. This was accompanied by decreased cardiac ir-ANP content. However, at the 7th day of DOCA-salt treatment, both plasma and cardiac ir-ANP levels of DOCA-salt rats were not different from those of control animals. At the 28th day, DOCA-salt rats had high plasma ir-ANP levels and no significantly different cardiac ir-ANP content compared to the controls. These data suggest that there are time-related changes in plasma ANP concentration during the development of DOCA-salt hypertension and higher plasma ANP levels might not necessarily be associated with a decreased cardiac ANP content.

Animals↗
PubMed1990

Bovine atrial natriuretic peptide in heart failure.

The present study describes the concentration and molecular form of atrial natriuretic peptide (ANP) in Holstein dairy cattle with mild (bacterial endocarditis; BEC) or severe (dilated cardiomyopathy; DCM) heart failure. Significant increases in plasma concentration of ANP were observed in cattle with DCM (73.3 +/- 16.02 pmol/l, n = 4, P less than 0.01) and BEC (20.6 +/- 3.45 pmol/l, n = 7, P less than 0.05), when compared with those in control cattle (14.5 +/- 1.84 pmol/l, n = 12). The concentration of ANP in cattle with DCM was significantly (P less than 0.01) higher compared with that in cattle with BEC. Plasma concentration of ANP correlated significantly with right atrial pressure (r = 0.95, P less than 0.01) and left ventricular end-diastolic pressure (r = 0.84, P less than 0.01). Gel-permeation chromatography of ANP in plasma and the right atrium from control and cattle with BEC revealed a single peak corresponding to the elution position of authentic human ANP(99-126) in plasma, and two peaks corresponding to those of authentic human ANP(99-126) and pro-ANP in the atrial extract. In cattle with DCM, however, peaks corresponding to the elution positions of authentic human beta-ANP and/or pro-ANP were detected in addition to the peak corresponding to ANP(99-126). The content of ANP in the right atrium of cattle with DCM was significantly (P less than 0.05) increased compared with that in control cattle and those with BEC. The present study therefore suggests that the synthesis and secretion of ANP might be stimulated by atrial distention induced by increased atrial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Distribution of tyrosine hydroxylase (TH)-like, neuropeptide Y (NPY)-like immunoreactive and acetylcholinesterase (AChE)-positive nerve fibers in the prostate gland of the monkey (Macacus fuscatus).

Nerve fibers containing immunoreactivities for tyrosine hydroxylase (TH) and neuropeptide Y (NPY), and exhibiting acetylcholinesterase (AChE) reactivity were examined by means of histochemical and immunohistochemical methods in the caudal lobe of the prostate in the monkey, Macacus fuscatus. TH-like immunoreactive nerve fibers were distributed abundantly in the interstitium where smooth muscle fiber bundles were rich and scarcely in the paraurethral region where they were rare. NPY-like immunoreactive nerve fibers, less abundant than TH-like immunoreactive nerve fibers, were observed not only in the interstitium but also around the prostatic acini. AChE-positive nerve fibers were much denser around the acini than in the interstitium. Both the NPY-like immunoreactive and the AChE-positive nerve fibers showed an intimate spatial association with the epithelium of the acini. Judging from the distribution pattern of these nerve fibers, the following assumption is possible. Secretion of the prostatic gland as well as the outflow of the prostatic fluid into the urethra induced by contraction of the smooth muscle cells in the interstitium may be controlled by sympathetic adrenergic nerves, while cellular secretion of the acinar epithelium is regulated by parasympathetic cholinergic nerves. The NPY-like immunoreactive nerve fibers around the acini may be non-noradrenergic; they may regulate the cellular secretion by acting on the cholinergic nerves as well as by having a direct effect on the acinar secretory cells.

Acetylcholinesterase↗
PubMed1990

Immunological responses in germfree mice infected with murine cytomegalovirus.

The immunological response of spleen cells was examined during murine cytomegalovirus (MCMV) infection of germfree (GF) mice. GF mice were more susceptible to MCMV infection than specific pathogen-free (SPF) mice. Recovery from the acute phase of MCMV infection was delayed in GF mice as compared to SPF mice. During MCMV infection, the immune response of GF mice, measured in terms of mitogen and of antibody response to sheep erythrocytes, was more markedly depressed and the recovery from the depression was more delayed than in SPF mice. In MCMV-infected mice, natural killer (NK) cell activity was increased by day 1 and 2 post-infection, with similar kinetics in GF and SPF mice, suggesting that NK cells may be exerting the most potent antiviral effect during the early stage of MCMV infection.

Animals↗
PubMed1990

Concurrent murine cytomegalovirus and Klebsiella pneumoniae infections in germfree mice.

The effects of concurrent murine cytomegalovirus (MCMV) and Klebsiella pneumoniae infections were studied in germfree (GF) mice. The mice received sublethal doses, 5 x 10(5) pfu, of MCMV. K. pneumoniae was injected in doses of 40 to 100 cfu, which by itself killed 0-33% of GF mice. When K. pneumoniae was given to GF mice infected with MCMV, the mortality increased up to 100%, with distinct enhancement persisting until day 10 of the MCMV infection. The virus titer in various organs did not change after superinfection with K. pneumoniae, while the viable counts of K. pneumoniae in organs remained remarkably high until death, suggesting the cause of death to be severe generalized infection by the bacteria. When compared to specific pathogen-free (SPF) mice, GF mice were more susceptible to both MCMV and K. pneumoniae infection, had higher titers of the virus for longer periods in various organs, and showed extension in the duration of enhanced mortality by the bacteria. Histopathologically, the spleen and liver were found to be the most severely affected tissues, more so in GF than in SPF mice, with recovery from the changes being slower in the GF animals.

Animals↗
PubMed1990

[Pulsatile LH secretion and hypothalamic-pituitary function in amenorrheic women].

In order to evaluate hypothalamic-pituitary function and pulsatile LH secretion in 42 amenorrheic women, blood was collected every 20 min. for 6 hrs. The mean LH pulse frequency (LH-pf) of women with a normal cycle, PCO and hyperprolactinemia was 3.4 +/- 0.5, 5.2 +/- 0.8, and 1.6 +/- 1.0/6 hrs, respectively. Hypothalamic amenorrhea (HA) with no progesterone withdrawal bleeding showed a lower frequency of LH secretion. As LH-pf in HA with progesterone withdrawal bleeding (HAI) ranged from 0 to 5/6 hrs, the HAI group was divided into 2 groups according to whether their LH-pf was less than 3.4/6 hrs (HAIa) or more (HAIb). Pituitary response to 100 micrograms of LH-RH in HAIb was much lower than in HAIa and PCO. On the other hand, in HA with LH-pf less than 3.4, LH-pf showed a significant correlation with basal LH and FSH levels and the LH increase to 100 micrograms of LH-RH, while in HA with LH-pf greater than or equal to 3.4, LH-pf had no significant correlation with them. In PCO, a high LH pulse frequency and amplitude and LH response to 100 micrograms of LH-RH were shown, but the LH increase to 100 micrograms of LH-RH was significantly reduced with the increase in LH-pf. Pituitary response to 100 micrograms of LH-RH in women with hyperprolactinemia was maintained despite low LH-pf. These results suggest that the analysis of pulsatile LH secretion is very helpful in evaluating hypothalamic-pituitary function in amenorrheic women.

Amenorrhea↗
PubMed1990

[Resin adhesion on the primary ground enamel. (Report 1). Influence of the etching times].

The purpose of this study was to investigate the influence of the etching times on the adhesion of the resion on the primary ground enamel. Fifty extracted and frozen bovine mandibular primary incisors were used. The etchant used in this study was 40% phospholic acid gel and the etching times were 0, 10, 20, 30 and 60 seconds. All of the specimens were washed with an air water spray for 30 seconds after etching. The bonding agent and composite resin used in this study were Photo Bond and Photo Clearfil A (Kuraray Co.). Shear bond strength on the ground enamel were measured. After the shear bond strength test, all the test surfaces of the enamel and resin specimens were observed using the SEM. The following conclusions were observed. 1) The etching time which showed the highest bond strength was 30 seconds (80.10 +/- 13.01 MPa). 2) When the enamel was etched with all of the etching times, the bond strengths were significantly higher than that of the enamel without etching. 3) The bond strength with 10 seconds of etching time was significantly higher than that with 20 seconds of etching time, and the bond strength with 30 seconds of etching time was significantly higher than that with 10 seconds of etching time, and the bond strength with 30 and 60 seconds of etching time was significantly higher than that with 20 seconds of etching time. 4) On the enamel specimens after the shear bond strength test, clear prism structures were observed in the group which showed a higher bond strength. 5) On the enamel specimens after the shear bond strength test, the frequency of the resin tags were fractured inside of the enamel prisms was lower in the group which showed a higher bond strengths. 6) Thirty seconds is a sufficient time for etching on the primary ground enamel using Photo Bond and Photo Clearfil A.

Acid Etching, Dental↗
PubMed1990

Concentrations of atrial natriuretic peptide in plasma and urine of kidney disease patients.

Concentrations of human atrial natriuretic peptide-like immunoreactivity (hANP-LI) were measured by a highly sensitive and specific radioimmunoassay (Biochem Biophys Res Commun 1986;137:231-6) in normal subjects and in renal disease patients without accompanying congestive heart failure, hypertension, edema, diabetes, or pregnancy. We attempted to clarify whether the hANP-LI concentration in plasma was increased by loss of renal mass. We found no correlation between the hANP-LI concentration in plasma and creatinine clearance (Ccr, 4.6-122.3 mL/min) in patients with renal disease (n = 63, r = -0.196), nor between hANP-LI concentrations in plasma and urine (n = 97, r = -0.207). The fractional excretion of hANP (FEhANP) correlated significantly with Ccr (n = 63, r = 0.520, P less than 0.01) and with FENa (n = 35, r = -0.503, P less than 0.01). Increased FEhANP in patients with chronic renal failure may have resulted because of an increase in single-nephron glomerular filtration rate similar to the FENa increase in these patients. The present data indicate that decreased renal function itself does not increase the concentration of hANP-LI in plasma.

Adolescent↗