Biomedical subjects

K R Kim

Publications and source records attributed to K R Kim.

At least 73 records · Page 4Linked to original sources

PubMed1999

Cadmium binding and sodium-dependent solute transport in renal brush-border membrane vesicles.

Exposure to cadmium (Cd) impairs renal transport systems for glucose, amino acids, phosphate, and dicarboxylates. To investigate if these changes are directly related to a Cd binding to the renal brush-border membrane, Cd binding and the Na+-dependent uptakes of d-glucose, l-alanine, phosphate, and succinate were determined in rat renal brush-border membrane vesicles (BBMV) exposed to CdCl2. Cd uptake by BBMV showed time and concentration dependence. Changes in medium osmolality had no effect on Cd uptake, indicating that the process primarily involves binding of Cd to the membrane. Scatchard analysis indicated the presence of two types of Cd binding sites, differing in affinity and number. Increasing the medium Cd concentration from 50 to 200 microM resulted in a progressive increase in Cd binding to the membrane and decrease in Na+-dependent transport of d-glucose, l-alanine, inorganic phosphate, and succinate. In all cases, the inhibition of transport was directly proportional to the total amount of Cd binding to the membrane. These results suggest that, during chronic exposure to Cd, free Cd ions liberated in renal tubular cells may directly interact with brush-border membranes and impair Na+-dependent solute transports.

Alanine↗

PubMed1999

Reduced erythropoietin responsiveness to anemia in diabetic patients before advanced diabetic nephropathy.

We often encounter diabetic patients with anemia in whom the causes of anemia were not clearly identified despite differential hematologic studies. We therefore studied the clinical and biochemical characteristics of diabetic patients with anemia of uncertain cause and measured erythropoietin (Epo) concentrations in 35 diabetic subjects without significant diabetic renal disease. Among 62 medical records of diabetic patients with anemia, showing no evidence of advanced diabetic nephropathy (creatinine clearance > or = 30 mg/kg/1.73 m2), the causes of the anemia were not able to be identified in 28 cases (45.2%). In addition, we enrolled 35 diabetic patients with uncertain causes of anemia in order to evaluate the serum Epo responsiveness to anemia, and compared levels to a group of non-diabetic subjects also with anemia. The serum Epo concentrations of diabetic patients (17.6 +/- 8.1 mIU/ml) were significantly lower than those of non-diabetic patients with similar degree of decrease in hemoglobin concentrations (144.9 +/- 108.0 mIU/ml, P<0.001). The hemoglobin concentrations of diabetic patients correlated with creatinine clearance (r = 0.34, P = 0.03), serum creatinine (r = -0.49, P = 0.003) and albumin excretion rate (r = -0.44, P = 0.009), but showed no relation to age, duration of diabetes, glycated hemoglobin, presence of retinopathy or neuropathy. We concluded that reduced Epo responsiveness to anemia could explain the anemia present in diabetic patient but without advanced diabetic nephropathy. This may reflect early renal interstitial damage.

Aged↗

PubMed1999

Gas chromatographic organic acid profiling analysis of brandies and whiskeys for pattern recognition analysis.

An efficient gas chromatographic profiling and pattern recognition method is described for brandy and whiskey samples according to their organic acid contents. It involves solid-phase extraction of organic acids using Chromosorb P with subsequent conversion to stable tert-butyldimethylsilyl derivatives for the direct analysis by capillary column gas chromatography and gas chromatography-mass spectrometry. A total of 12 organic acids were reproducibly identified in liquor samples (1 mL). When the GC profiles were simplified to their retention index spectra, characteristic patterns were obtained for each liquor sample as well as for each group average. Stepwise discriminant analysis provided star symbols characteristic for each liquor sample and group average. As expected, canonical discriminant analysis correctly classified 23 liquor samples studied into two groups of either brandy or whiskey.

Alcoholic Beverages↗

PubMed1999

Low-dose growth hormone treatment with diet restriction accelerates body fat loss, exerts anabolic effect and improves growth hormone secretory dysfunction in obese adults.

Growth hormone (GH) can induce an accelerated lipolysis. Impaired secretion of GH in obesity results in the consequent loss of the lipolytic effect of GH. Dietary restriction as a basic treatment for obesity is complicated by poor compliance, protein catabolism, and slow rates or weight loss. GH has an anabolic effect by increasing insulin-like growth factor (IGF)-I. We investigated the effects of GH treatment and dietary restriction on lipolytic and anabolic actions, as well as the consequent changes in insulin and GH secretion in obesity. 24 obese subjects (22 women and 2 men; 22-46 years old) were fed a diet of 25 kcal/kg ideal body weight (IBW) with 1.2 g protein/kg IBW daily and were treated with recombinant human GH (n = 12, 0.18 U/kg IBW/week) or placebo (n = 12, vehicle injection) in a 12-week randomized, double-blind and placebo-controlled trial. GH treatment caused a 1.6-fold increase in the fraction of body weight lost as fat and a greater loss of visceral fat area than placebo treatment (35.3 vs. 28.5%, p < 0.05). In the placebo group, there was a loss in lean body mass (-2.62 +/- 1.51 kg) and a negative nitrogen balance (-4.52 +/- 3.51 g/day). By contrast, the GH group increased in lean body mass (1.13 +/- 1.04 kg) and had a positive nitrogen balance (1.81 +/- 2.06 g/day). GH injections caused a 1.6-fold increase in IGF-I, despite caloric restriction. GH response to L-dopa stimulation was blunted in all subjects and it was increased after treatment in both groups. GH treatment did not induce a further increase in insulin levels during an oral glucose tolerance test (OGTT) but significantly decreased free fatty acid (FFA) levels during OGTT. The decrease in FFA area under the curve during OGTT was positively correlated with visceral fat loss. This study demonstrates that in obese subjects given a hypocaloric diet, GH accelerates body fat loss, exerts anabolic effects and improves GH secretion. These findings suggest a possible therapeutic role of low-dose GH with caloric restriction for obesity.

Adipose Tissue↗

PubMed1999

GH-binding protein in obese men with varying glucose tolerance: relationship to body fat distribution, insulin secretion and the GH-IGF-I axis.

Bioelectrical impedance for measurement of total body fat and computed tomography for visceral and subcutaneous fat at umbilicus levels were performed in 34 obese and 10 lean men. Insulin secretion in response to an oral glucose tolerance test (OGTT) and a GH stimulation test by L-dopa, growth hormone-binding protein (GHBP) and IGF-I were measured. Obese subjects were divided into three groups according to the OGTT. The obese type II diabetes mellitus group had the highest GHBP levels and the most visceral fat. GHBP levels were most strongly correlated with the ratio of visceral fat area to body weight (VWR) above any other parameters (r = 0.725, P<0.001). The insulin and free fatty acid (FFA) areas under curves (AUC) during the OGTT, and the IGF-I level, were also positively correlated with GHBP levels (r = 0.474, P<0.005; r = 0.572, P<0.005; r = 0.453. P<0.005). GH-AUC to the L-dopa stimulation test was negatively correlated with GHBP levels (r = -0.432. P<0.005). Stepwise multiple linear regression analysis showed that VWR, FFA-AUC and insulin-AUC significantly contributed to the variability of GHBP (r2 = 0.58). In conclusion, we demonstrated that: (i) visceral fat amount mainly determined GHBP levels in obese men with varying glucose tolerance: (ii) hyperglycemia per se did not influence the GHBP level, whereas insulin and FFA could play a role in regulation of GHBP: and (iii) although GH was not the main regulator of GHBP, the unchanged IGF-I level despite GH hyposecretion suggests that increased GHBP levels reflect GH hypersensitivity in order to compensate for decreased GH secretion in obesity.

Adipose Tissue↗

PubMed1999

The validity of random urine specimen albumin measurement as a screening test for diabetic nephropathy.

To assess the validity of urine albumin concentration (UAC) and the urine albumin:creatine ratio (UACR) in a random urine specimen (RUS) for screening diabetic nephropathy in Korea, a total of 105 ambulatory diabetes mellitus patients (male:female, 52:53), ages 40-75 years (median 59 years) collected 105 RUSs after completing a timed 24 hour urine collection. Albumin was measured by immunonephelometry. According to the timed urinary albumin excretion rate (UAER) measured in the 24 hour collection (criterion standard), samples were classified normoalbuminuric (UAER < 20 micrograms/min; n = 50), microalbuminuric (UAER 20-200 micrograms/min; n = 30), and macroalbuminuric (UAER > 200 micrograms/min; n = 25). The receiver operating characteristics (ROC) curve of UAC and UACR in a RUS for screening of microalbuminuria (normo- and microalbuminuric samples; n = 80) and macroalbuminuria (micro- and macroalbuminuric samples; n = 55) were plotted. Pearson's coefficients of correlation of 24 hour UAER vs. UAC and UACR were 0.81 and 0.75, respectively (P < 0.001). The point of intersection with a 100%-to-100% diagonal for microalbuminuria were as follows: 31.0 mg/l for UAC and 32.5 mg/g for UACR; for macroalbuminuria 181 mg/l for UAC and 287.3 mg/g for UACR. The sensitivity and specificity of the cut-off points for microalbuminuria were 77% and 82% for UAC and 77% and 92% for UACR. The sensitivity and specificity of the cut-off points for macroalbuminuria were 84% and 90% for UAC and 88% and 90% for UACR. In present study, no difference was observed when comparing the performance of UAC and UACR based on a statistical comparison by McNemar test. The repeated measurements of UAC and UACR in the same individual were statistically similar and were correlated with each other. Based on these results, albumin measurements (UAC and UACR) in a RUS were considered as a valid test for screening diabetic nephropathy.

Adult↗

PubMed1998

Gas chromatographic profiling and pattern recognition analysis of urinary organic acids from uterine myoma patients and cervical cancer patients.

An efficient organic acid profiling and pattern recognition method is described for the correlation between urinary organic acid profiles and uterine cervical cancer. After methoximation of keto acids in alkalinized urine samples, all free organic acids were recovered by a dual solid-phase extraction procedure, followed by conversion to tert.-butyldimethylsilyl derivatives for the profiling analysis by dual-capillary column gas chromatography (GC) with subsequent screening for acids by retention index (I) library matching. A total of 50 organic acids were positively identified in urine samples (0.25 ml) from 12 uterine myoma (benign tumor group) and 14 uterine cervical cancer (malignant tumor group) patients studied. When the GC profiles were simplified to their corresponding organic acid I spectra in bar graphical form, characteristic patterns were obtained for each average of benign and malignant tumor groups. Stepwise discriminant analysis performed on the GC data selected 16 acids as the variables discriminating between the two groups. Canonical discriminant analysis applied to these 16 variables correctly classified 26 urine samples into two separate clusters according to tumor types in the canonical plot.

Adult↗

PubMed1998

Analysis of traditional Chinese anticancer drugs by capillary electrophoresis.

The results reported in this communication demonstrate that capillary zone electrophoresis (CZE) can be used easily for the quantitative determination of the potential anticancer drugs berberine and isoguanosine in the extract of the traditional Chinese medicinal herb. Isoguanosine and berberine can be monitored selectively and sensitively at 254 nm within 14 min in the plant extract using a 100-mM sodium citrate running buffer (adjusted to pH 2.7; applied voltage 12 kV). The concentration range of 0.1-50 micrograms ml-1 proved to be sufficient for exact quantification and the peak profile showed good reproducibility [relative standard deviations (n = 32); for the migration time 0.22% (isoguanosine) and 1.32% (berberine); for the peak area 2.8% (isoguanosine) and 3.2% (berberine)]. The measured concentrations in the crude extract were 1.3 micrograms ml-1 for isoguanosine and 8.7 micrograms ml-1 for berberine. In addition to the better separation performance, CZE shows several other remarkable advantages over high-performance liquid chromatography (HPLC), such as rapidity of analysis, small sample volume, no requirement of organic solvent in the running buffer and low cost of reagents.

Antineoplastic Agents, Phytogenic↗

PubMed1998

Renal transport systems for organic anions and cations in cadmium-exposed rats.

To evaluate the effect of cadmium intoxication on renal transport systems for organic anions and cations, transport of p-aminohippurate (PAH) and tetraethylammonium (TEA) were studied in renal cortical plasma membrane vesicles isolated from cadmium-intoxicated rats. Cadmium intoxication was induced by daily injections of CdCl2 (2 mg Cd/kg.day sc) for 2-3 weeks. Renal plasma membrane vesicles were prepared by Percoll gradient centrifugation and magnesium precipitation method. Vesicular uptake of substrate was determined by rapid filtration technique using Millipore filter. The cadmium treatment resulted in a marked attenuation of Na(+)-dependent, alpha-ketoglutarate (alpha KG)-driven PAH uptake in the basolateral membrane vesicle (BLMV), and this was due to a reduction in Vmax and not K(m). The Na(+)-alpha KG symport activity of the BLMV was not affected by 2-week cadmium treatment, but it was significantly inhibited by 3-week cadmium treatment. On the other hand, the alpha KG-PAH antiport activity of the BLMV appeared to be markedly suppressed in 2-week as well as 3-week cadmium-treated animals. The cadmium treatment inhibited the proton gradient-dependent TEA transport in the brush-border membrane vesicle (BBMV), and this was associated with a reduction in Vmax with no change in K(m). These results indicate that cadmium exposures may impair the capacities for organic anion transport in the proximal tubular basolateral membrane and organic cation transport in the luminal membrane. The cadmium effect on organic anion transport is attributed mainly to an inhibition of dicarboxylate-organic anion antiport system.

Animals↗

PubMed1998

Genotoxicity study of bojungchisup-tang, an oriental herbal decoction-in vitro chromosome aberration assay in Chinese hamster lung cells and in vivo supravital-staining micronucleus assay with mouse peripheral reticulocytes.

The toxicity evaluation of oriental herbal drugs is of great concern at present. Bojungchisuptang (BCST, in Korean), a decocted medicine of oriental herbal mixture, is now well used in clinic at oriental hospitals for the treatment of edema of several diseases in practice. However, the toxicity of the oriental herbal decocted medicines such as genetic toxicity is not well defined until now. In this respect, to clarify the genetic toxicity of BCST, in vitro chromosome aberration assay with Chinese hamster lung (CHL) fibroblasts and in vivo supravital micronucleus assay with mouse peripheral reticulocytes were performed in this study. In the chromosome aberration assay, we used 5,000 micrograms/ml BCST as maximum concentration because no remarkable cytotoxicity in CHL cells was observed both in the presence and absence of S-9 metabolic activation system. No statistical significant differences of chromosome aberrations were observed in CHL cells treated with 5,000, 2,500 and 1,250 micrograms/ml BCST for 6 hour both in the presence and absence of S-9 metabolic activation. However, very weak positive result (6.5-8.0% aberration) of BCST was obtained in the absence of S-9 metabolic activation system at 5,000 micrograms/ml BCST when treated for 24 hour, i.e. 1.5 normal cell cycle time. And also, in vivo clastogenicity of BCST was studied by acridine orange-supravital staining micronucleus assay using mouse peripheral reticulocytes. We used 2,000 mg/kg as the highest oral dose in this micronucleus assay because no acute oral toxicity of BCST was observed in mice. The optimum induction time of micronucleated reticulocytes (MNRETs) was determined as 36 hours after oral administration of 2,000 mg/kg BCST. No significant differences of MNRETs between control and BCST treatment groups were observed in vivo micronucleus assay. From these results, BCST revealed very weak positive result in chromosome aberration assay in vitro with CHL cells and no clastogenicity in micronucleus assay in vivo.

Animals↗

PubMed1998

Goblet-cell mucinous epithelium lining the endometrium and endocervix: evidence of metastasis from an appendiceal primary tumor through the use of cytokeratin-7 and -20 immunostains.

Differential staining with cytokeratin (CK)-7 and CK-20, two members of a complex family of proteins in human epithelial cells, proved critical in showing that the extremely well-differentiated goblet-cell (intestinal) mucinous epithelium lining the surface of the endometrium and endocervix in two patients and the fallopian tube in one was identical to that of the coincident appendiceal neoplasms. One of these patients also had a large ovarian tumor that grossly and microscopically resembled a mucinous cystadenoma of borderline malignancy and would have been considered primary except for the CK stains (CK-20 positive and CK-7 negative), which suggested metastasis from the appendix, presumably by a transtubal route.

Appendiceal Neoplasms↗

PubMed1998

Dietary iodine intake and urinary iodine excretion in normal Korean adults.

Korea is a region abundant in foods containing iodine such as seaweed and fish. An adequate amount of iodine consumption is extremely important as both a deficiency and excess of iodine can result in health problems. This study was undertaken to assess the iodine nutritional status of normal Korean adults who consume seaweed and fish, and to determine the relationship between the dietary iodine intake and the urinary excretion of iodine. The dietary assessment of iodine using a food frequency questionnaire and a urinary iodine excretion examination were carried out in 278 healthy adults. The iodide selective electrode (ISE) method was used to determine urinary iodine excretion. The average usual iodine intake of Korean adults was 479 micrograms per day (ranging from 61 micrograms to 4086 micrograms). There was no significant difference in sex or age. The major food sources of dietary iodine included seaweed (66%), milk and dairy products (11%), and fish (9%). The contribution of seaweed to the total iodine intake tended to increase with age while the contribution of milk decreased. The average urinary excretion of iodine was 674 micrograms/g creatinine and there was no significant difference in sex or age. The dietary iodine intake was positively correlated with the urinary excretion of iodine (gamma = 0.60, p < 0.01). The study data indicated that the iodine intake and excretion of Koreans depends mostly on the amount of seaweed consumption like sea tangle and sea mustard. As well, the current iodine intake and urinary iodine excretion by Koreans seems to be higher than in other countries.

Adult↗

PubMed1997

Gas chromatographic profiling analysis of urinary organic acids from nonsmokers and smokers.

A rapid profiling and screening procedure is described for the comparative analysis of urinary organic acids among the groups of nonsmokers and smokers. The procedure involves solid-phase extraction of organic acids using Chromosorb P in normal-phase partition mode, with subsequent single-step conversion to tert.-butyldimethylsilyl derivatives, followed by direct gas chromatographic (GC) analysis on dual-capillary columns. A total of forty-two organic acids were positively identified by retention index (I) matching in urine samples (0.25 ml) from eleven nonsmokers and fifteen smokers studied. When the GC profiles were simplified to their corresponding organic acid I spectra in bar graphical form, characteristic patterns were obtained for each individual as well as for each average of nonsmoking and smoking groups. When stepwise discriminant analysis was performed on GC data after omitting hippuric acid, seven acids were selected as the variables most discriminating between smokers and nonsmokers. The star symbol plots drawn based on these discriminants were characteristic of each individual and group average, enabling to distinguish smokers from nonsmokers. And canonical plot produced by canonical discriminant analysis using the same variables as the data vectors displayed two separate clusters representing each group.

Adult↗

PubMed1997

Effect of cadmium on Na-Pi cotransport kinetics in rabbit renal brush-border membrane vesicles.

Chronic exposure to cadmium impairs various renal functions, including phosphate (Pi) transport. To further investigate the mechanism of cadmium-induced alterations in renal Pi transport, kinetics of Na+-dependent Pi uptake were studied in renal cortical brush-border membrane vesicles (BBMV) exposed to CdCl2 in vitro. BBMVs isolated from rabbit renal outer cortex were preincubated in a buffer containing CdCl2 (50 microM in most cases) for 60 min at 37 degrees C and then tested for Pi uptake at 25 degrees C. CdCl2 treatment resulted in a marked attenuation of Na+-dependent Pi uptake with no changes in Na+-independent Pi uptake and membrane permeability to Na+. CdMt treatment induced no changes in Pi transport. The inhibition required preincubation of vesicles with CdCl2 for more than 30 min and was not reversed by extravesicular EDTA, suggesting that cadmium affects the transport system at the internal side of the membrane. Kinetic analysis indicated that two sodium ions and one phosphate ion interact with a carrier, and this stoichiometry was not altered by cadmium treatment. Cadmium treatment did not change the apparent Km for Na+ (K(Na)) and that for phosphate (K(Pi)), but it markedly reduced the Vmax of the Na+-dependent Pi transport. These results indicate that exposure of proximal tubular brush border membranes to cadmium impairs the Pi transport capacity, probably by reducing the effective number of Na-Pi cotransporter units without altering substrate affinities of the carrier.

Animals↗

PubMed1997

Rapid gas chromatographic profiling and screening of biologically active amines.

An efficient method is described for the simultaneous determination of 57 amines including volatile aliphatic amines, nonvolatile polyamines and catecholamines present in aqueous samples. The method is based on two-phase isobutyloxycarbonylation (isoBOC) with a pH shift. In 1.0 M phosphate buffer at pH 7.5, phenolic hydroxyl groups were allowed to react with isobutyl chloroformate in the dichloromethane phase, and subsequently pH of the aqueous phase was increased to 12.0 for the reaction of basic amino functions. The resulting N(O)-isoBOC amines were recovered by solid-phase extraction using Chromosorb P in normal phase partition mode, with subsequent tert.- butyldimethylsilylation of the remaining hydroxyl groups for gas chromatographic analysis. Using this combined procedure, linear responses were obtained in the concentration range of 0.2-12 ppm, with correlation coefficients varying from 0.945 to 0.999 for most of the amines studied except for 5-methoxytryptamine (0.864). Temperature-programmed retention index (I) sets as measured on DB-5 and DB-17 dual-capillary columns of different polarity were characteristic of each amine and thus, useful in the screening for amines by computer I matching. When applied to saliva samples, the present method allowed rapid screening for each spiked amine and unspiked polyamines such as 1,3-diaminopropane, putrescine, cadaverine and spermidine.

Amines↗

PubMed1997

Effect of obesity on total and free insulin-like growth factor (IGF)-1, and their relationship to IGF-binding protein (BP)-1, IGFBP-2, IGFBP-3, insulin, and growth hormone.

OBJECTIVES: We investigated the effect of obesity on the serum levels of total and free IGF-1 and their relationship to the circulating levels of insulin and IGF binding proteins (IGFBPs) in age and sex-matched groups. SUBJECTS: The study included 43 obese subjects (ideal body weight; IBW > 120%) and 45 controls (IBW < 100%). All of the subjects were male. MEASUREMENT: Total IGF-1, free IGF-1, IGFBP-1, IGFBP-2, IGFBP-3, and insulin were measured in obese subjects and normal control subjects. RESULTS: No significant differences in the circulating levels of total and IGFBP-3 were observed between the obese and control groups. In contrast to total IGF-1, free IGF-1 in obese subjects was significantly increased compared to normal controls (P < 0.05). Serum total and free IGF-1 were inversely correlated with age (r = -0.42, P = 0.001, and -0.44, P = 0.001). Fasting serum insulin concentrations were elevated in all the obese subjects (P < 0.05) and positively correlated with IBW (r = 0.57, P = 0.001). The levels of serum GH and IGFBP-1 were suppressed in all the obese subjects (P < 0.05). IGFBP-1 was inversely correlated with IBW (r = -0.51, P = 0.001) and serum insulin concentrations (r = -0.48, P = 0.001). The IGFBP-2 concentrations were also suppressed in obese subjects and inversely related to free IGF-1 (r = -0.48, P = 0.001). Using multiple linear regression analysis, total IGF-1 and insulin concentrations were positively correlated (r = 0.58, P = 0.001) and free IGF-1 and IGFBP-1 concentrations were negatively correlated (r = -0.57, P = 0.001). CONCLUSION: We confirmed that total IGF-1 and IGFBP-3 concentrations were not significantly different between the obese and control groups, despite GH hyposecretion in obesity. We also found that free IGF-1 concentrations were higher in obese subjects than in normal controls. It seems likely that overnutrition and chronic hyperinsulinaemia in obesity may alter this regulated growth response by insulin stimulation of IGF-1 production and suppression of hepatic IGFBP-1 and IGFBP-2 production, which may inhibit IGF-1 bioactivity.

Adult↗

PubMed1997

Altered hydroxylation of estrogen in patients with postmenopausal osteopenia.

To study the possible contributions of the differences in estrogen metabolism to bone mass in postmenopausal osteopenia, spinal and femoral bone mineral densities (BMD) were measured, and 18 urinary metabolites of estrogen were analyzed by a gas chromatography-mass spectrometry assay system in 59 postmenopausal women (5-10 yr after menopause). The BMD of the spine and femoral neck showed positive correlations with body weight, height, and body mass index as we expected. Compared to nonosteopenic subjects, there were no significant differences in serum estrone (E1) and estradiol (E2) levels in patients with osteopenia. However, the urinary 16 alpha-hydroxyestrone [16 alpha-(OH)E1] level was significantly lower in patients with spinal osteopenia (P < 0.001). Among the 18 urinary metabolites of estrogen, the 16 alpha-(OH)E1 and 16 alpha-(OH)E1/2-hydroxyestrone [2-(OH)E1) ratio showed positive correlations with spinal BMD (P < 0.05), whereas 2-(OH)E2 showed a negative correlation with femoral neck BMD (P < 0.05). The urinary 16 alpha-(OH)E1 level also revealed a positive correlation with the age-matched z score of BMD in the spine (P < 0.05). In multiple stepwise regression analysis, weight, 16 alpha-(OH)E1, interaction between 16 alpha-(OH)E1 and 2-(OH)E2, 2-(OH)E2, and years after menopause were statistically significant for spinal BMD (r2 = 0.4968). For femoral neck BMD and weight, 16 alpha-(OH)E1 and 2-(OH)E2 were the independent determinants (r2 = 0.3369). In conclusion, the activity of estrogen 16 alpha-hydroxylase was decreased and/or the activity of estrogen 2-hydroxylase was enhanced in post-menopausal osteopenia. We speculated that these derangements may serve as contributing factors for the acceleration of bone loss in post-menopausal osteoporosis.

Aged↗

PubMed1997

Effect of physical exercise on renal response to head-out water immersion.

Head-out water immersion (HOI) induces various renal functional changes, such as diuresis, natriuresis, and kaliuresis. The present study was undertaken 1) to characterize the renal response to HOI in Koreans who routinely ingest high salt diet and 2) to evaluate the impact of exercise on the renal response to HOI. Six healthy male subjects (average Na+ intake of 232 mEq.day-1) were immersed upto the neck in 34.5 degrees C water and rested in a seated position or exercised on a bicycle ergometer for 3 hours. In resting subjects, we observed a reversible increase in urine flow and a decrease in urine osmolality, with no changes in creatinine clearance. The peak urine flow observed during the second hour of immersion was 4-fold greater than the pre-immersion level. The excretion of total osmotic substances rose progressively during the 3-hour immersion, which was accompanied by a similar change in Na+ excretion. The K+ excretion was slightly elevated. The major component of the immersion diuresis was a water diuresis in the early phase and an osmotic diuresis in the late phase of immersion. In exercising subjects, the diuretic and natriuretic responses to HOI were attenuated and the kaliuretic response was potentiated. Blood hemoglobin concentration and plasma levels of renin, ADH, and aldosterone decreased during immersion-rest, but they remained unchanged or increased during immersion-exercise. These results suggest that 1) the cardiac mechanoreceptor-mediated renal responses to HOI are not changed by chronic high salt diet, and 2) excessive urinary sodium and water losses are prevented by exercise during immersion.

Adult↗