In vivo pharmacokinetics of aldose reductase inhibitors: 3-fluoro-3-deoxy-D-glucose NMR studies in rat brains

Direct quantification of the inhibitory effects of orally administered drugs (sorbinil, cyclandelate and sulindac) on aldose reductase activities in rat brains was performed non-invasively using the 3-fluoro-3-deoxy-D-glucose (3-FDG) 19F NMR spectroscopic technique. Quantitative data obtained directly from the target organ (brain) allowed for unprecedentedly accurate analysis of drug effects in the brain in vivo. Sorbinil, a potent aldose reductase inhibitor, exhibited a classic monophasic organ response, whereas cyclandelate and sulindac showed biphasic suppression patterns. The latter indicate that there are metabolites of these drugs which possess aldose reductase inhibitory activities. The estimated potency of aldose reductase inhibition for each of the three drugs in this study was significantly discrepant from the in vitro studies indicating the complicated nature of the bioavailability of a pharmaceutical agent in vivo, especially where pharmacologically active metabolites of a given drug are involved. Our method allows for a direct quantitative assay and hence the most reliable technique for evaluating aldose reductase inhibitory activities in the target organ.     

Albumin escape from microvessels in kidney, heart and skeletal muscle in experimental diabetes mellitus in the anaesthetized rat.

Diabetes was induced with streptozotocin in rats weighing about 160 g. These were maintained with age-matched controls for up to 14 months, blood glucose being periodically monitored. Half the diabetic and control rats received the aldose reductase inhibitor, Ponalrestat, in their diet. Distribution of volumes of 131I-albumin (5 min) and 125I-albumin (100 min) were estimated in various tissues at 3 weeks, 6-7 months and 13-14 months of diabetes. The former space was assumed to represent the intravascular plasma space, while the latter was taken to include both the extravascular and intravascular albumin volumes in the kidney. In heart and skeletal muscle, equilibration between the specific activities of extravascular albumin and of plasma albumin was not assumed to be complete at 100 min. In the cortex and medulla of kidney, the extravascular albumin pool increased significantly at 13-14 months of diabetes (for both, P less than 0.01). Significantly increased entry of albumin into the interstitium occurred at 6 months (P less than 0.05) and at 13-14 months (P less than 0.01) in skeletal muscle, and at 13-14 months (P less than 0.05) in heart. The intravascular plasma volumes were not influenced by diabetes and the aldose reductase inhibitor had no effect at any time in either diabetic or control rats. These findings indicate increased movement of plasma albumin into the interstitium in the late phase of diabetes in the heart, skeletal muscle and in the kidney. Enlargement of the interstitial albumin pool is likely to affect the fluid balance between capillary and interstitium and may contribute to the effect of diabetes on the function of these organs.     

不同年龄脑出血大鼠海马齿状回神经干细胞增殖与分化差异的比较

BACKGROUND:Cerebral hemorrhage can activate the proliferation and differentiation of neural stem cells in the dentate gyrus of the hippocampus. Through continuous differentiation and proliferation, endogenous neural stem cells can gradually replace aging and damaged neurons, thus protecting the brain structure. OBJECTIVE:To compare the difference of the proliferation and differentiation of neural stem cells in the dentate gyrus of the hippocampus of rats with different ages. METHODS:Ninety-six adult rats and 96 aged rats were randomly divided into normal group (n=18 per group), sham operation group (n=12 per group) and cerebral hemorrhage group (model group, n=66 per group), respectively. Cerebral hemorrhage models were made in the two model groups in which, the rats were subjected to cerebral hemorrhage for 6, 24, 48, 72 hours and 7 days, respectively. Then, brain tissues were collected to measure brain water content. BrdU/NeuN and BrdU/GFAP double staining were performed at 3, 7, 14, 21, 28 days after surgery to calculate the number of positive cells. RESULTS AND CONCLUSION:For both adult and aged rats, the brain water content was significantly higher than that in the normal group and sham operation group (P < 0.05), while in the normal and sham operation groups, the brain water content was significantly lower in the aged rats than the adult rats (P  < 0.05). The number of bilateral BrdU-positive cells in the adult and aged model groups was significantly higher than that in the corresponding normal and sham operation groups (P  < 0.05), and moreover, the positive cell number at the hemorrhage side was significantly higher than that at the opposite side (P < 0.05). In addition, the number of BrdU-positive cells at the hemorrhage side in the adult rats was significantly higher than that in the aged rats at different time after cerebral hemorrhage (P  < 0.05). Results from immunohistochemical double staining showed that the BrdU/NeuN and BrdU/GFAP expression in the hippocampal dentate gyrus of adult rats with cerebral hemorrhage was significantly higher than that of normal adult rats. All these experimental results show that there are a few neural stem cells proliferating in the hippocampal dentate gyrus of normal rats, and the proliferation ability is stronger in the adult rats than the aged rats. Cerebral hemorrhage can significantly strengthen the proliferation of neural stem cells in the dentate gyrus in the adult rats compared with the aged rats.     

The Magnitude of Brain Lipid Peroxidation Correlates with the Extent of Degeneration but Not with Density of Neuritic Plaques or Neurofibrillary Tangles or with APOE Genotype in Alzheimer’s Disease Patients

Numerous post mortem studies have demonstrated increased accumulation of lipid peroxidation products in diseased regions of Alzheimer's disease (AD) brain; however, few have used techniques that quantify the magnitude of lipid peroxidation in vivo. F(2)-isoprostanes (F(2)-IsoP's) are exclusive products of free radical-mediated peroxidation of arachidonic acid, and their quantification has been widely used as an in vivo biomarker of the magnitude of lipid peroxidation. We have determined F(2)-IsoP concentrations in lateral ventricular fluid (VF) from 23 AD and 12 age-matched controls and correlated these with neuropathological and genetic markers of AD. VF F(2)-IsoP levels were significantly elevated in AD patients compared with controls (p < 0.01) and were significantly correlated with three different measures of brain degeneration: reduction in brain weight (p < 0.01), degree of cortical atrophy (p < 0.01), and Braak stage (p = 0.02). When analysis was restricted to AD patients only, VF F(2)-IsoP levels still were significantly correlated to reduction in brain weight and degree of cortical atrophy (p < 0.05). VF F(2)-IsoP concentrations were not related to density of neuritic plaques or neurofibrillary tangles in seven brain regions, or to the number of epsilon4 alleles of the apolipoprotein E gene (APOE). These data suggest that the magnitude of brain lipid peroxidation is closely related to the extent of brain degeneration in AD but is not significantly influenced by the density of neuritic plaques or neurofibrillary tangles, or the number of epsilon4 alleles of APOE.     

Radioimmunoassay of 5-androstene-3 beta, 17 beta-diol in plasma and breast cyst fluid

A simple and reliable radioimmunoassay for the determination of 5-androstene-3 beta,17 beta-diol (5-Adiol) in peripheral plasma and in breast cyst fluid, after chromatography on Celite microcolum has been described and evaluated. The antiserum used was raised in the rabbit injected with dehydroepiandrosterone-15 alpha-carboxymethyl-bovine serum albumin. In men below 40 years of age the levels ranged from 0.85 to 2.80 ng/ml (mean +/- SEM: 1.52 +/- 0.11; n = 24) and from 0.50 to 2.20 ng/ml (mean: 0.93 +/- 0.09; n = 20) in men aged between 41 and 62 years. The mean level was significantly different (p less than 0.001) between the two groups. A significant correlation (r = -0.56 p less than 0.01) was demonstrated between age and all male levels. In women the mean plasma level was in the follicular phase: 0.81 +/- 0.07 ng/ml (range: 0.40 - 1.50; n = 17; age: 19-41 years) and in the luteal phase: 0.83 +/- 0.05 ng/ml (range: 0.40 - 1.30; n = 29; age: 18-43 years). No cyclical change and no correlation with age could be evidenced. A significant difference (p less than 0.001) was shown between females and the young male group. In breast cyst fluid the levels of unconjugated 5-Adiol ranged from 0.05 to 13.70 ng/ml (mean: 2.21 +/- 0.73; n = 23) whereas the sulfate concentrations ranged from 75 to 7,500 ng/ml (mean: 1,973 +/- 543; n = 18), thus demonstrating very wide inter-individual variations.     

Non-invasive determination of cerebral blood flow changes by 19F NMR spectroscopy

The build-up and clearance of halothane in rat brain have been measured non-invasively by 19F NMR spectroscopy using a surface coil placed on the intact scalp. When the halothane supply (3% in O2/N2O, 33/66%) was turned off, the 19F signal decreased exponentially to approximately 50% of the initial value, with a time constant, in normal rats, of 8.6 +/- 0.7 min (mean +/- SEM, n = 16), followed by a decay slower by at least one order of magnitude. The time constant of the rapid decay (tau), which was found to be specific for brain, was reduced in hypoxic/hypercapnic (5% O2/5% CO2) rats to 2.9 +/- 0.2 min (p = 0.001, n = 4), in rats infused with physostigmine (20 micrograms/kg/min i.v.) to 5.7 +/- 0.3 min (p = 0.005, n = 6) and increased in rats injected with pentothal (40 mg/kg i.p.) to 10.7 +/- 1.6 min (p = 0.2, n = 5). Based on the theory of exchange of inert gas at the lungs and tissues developed by Kety, the rapid exponential decay of the 19F signal was used to calculate relative cerebral blood flow (CBF). Assuming the cortical CBF in a normal rat to be about 130 mL min-1 100 g-1, the following CBF values (means +/- SEM) were obtained: controls 130 +/- 10, hypoxia/hypercapnia 390 +/- 59, hypercapnia 220 +/- 25, physostigmine 195 +/- 26, pentothal 105 +/- 23 mL min-1 100 g-1. These values are in good agreement with published values obtained with established methods.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pattern of C3, iC3b, and C3d in patients hospitalized for acute asthma.

Twenty-three patients hospitalized for acute asthma were studied for a peripheral blood complement profile consisting of C3, C4, C3d, iC3b, C4d, and Bb concentrations. Compared with normals (n = 22) and patients (n = 10) with acute bacterial infections (ABI), asthmatic patients had significantly higher serum C3 concentrations (P less than .001). Plasma C3d levels and iC3b in asthmatic patients were both comparable to those observed in normal controls, whereas patients with ABI had significantly higher iC3b levels than both other groups. The ratio of iC3b to C3 concentrations were similar in asthmatic patients and controls, and iC3b levels were correlated with total serum C3 levels in asthmatic patients (r = .55, p less than .001) as well as in normal (r = .69, p less than .001). Both of these groups had significantly lower iC3b to C3 ratios compared with the ABI group (P less than .0001). Also observed in asthmatic patients were a significant correlation between serum C4 and C3 levels (r = .83, P less than .001) and a lower mean ratio of plasma C4d to C4 compared with normals (P less than .005). This profile of complement alterations is distinct from that observed in acute bacterial infection. These changes in asthmatic patients may relate to an acute phase reaction phenomenon affecting complement and/or complement regulatory proteins.     

Alveolar lymphocyte proliferation induced by Propionibacterium acnes in sarcoidosis patients

The proliferation of lymphocytes induced by Propionibacterium acnes (P. acnes) was measured by the in vitro incorporation of 3H-thymidine. The mean response rate of alveolar lymphocytes obtained by bronchoalveolar lavage was 2.23 +/- 0.89 in nine untreated sarcoidosis patients, 0.85 +/- 0.17 in five sarcoidosis patients given corticosteroids and 0.78 +/- 0.29 in 11 controls. The proliferation was significantly enhanced in the untreated patients compared to both the treated patients (p less than 0.01) and controls (p less than 0.001), but there was no significant difference in response rates between the treated patients and controls. The response rate of alveolar lymphocytes was significantly higher in four active patients (3.05 +/- 0.61) than in four inactive patients (1.77 +/- 0.44) (p less than 0.05) and in the controls (p less than 0.001). In sarcoidosis patients, the response rates showed a good correlation with activities of serum lysozyme (r = 0.695, p less than 0.01), and with percentages of lymphocytes in bronchoalveolar lavage fluid (r = 0.591, p less than 0.05). There was a low correlation between angiotensin-converting enzyme activities and the response rates (r = 0.508, p less than 0.1). Neither peripheral blood lymphocytes in sarcoidosis patients nor in controls showed any response to P. acnes, but alveolar lymphocytes of the untreated active sarcoidosis patients were sensitive to P. acnes. The lymphocytes activated by P. acnes may play a central role in the induction of alveolitis in sarcoidosis patients.     

A randomized, controlled trial of a geriatric assessment unit in a community rehabilitation hospital

We conducted a randomized trial in a community rehabilitation hospital to determine the effect of treatment in a geriatric assessment unit on the physical function, institutionalization rate, and mortality of elderly patients. Functionally impaired elderly patients (mean age, 78.8 years) who were recovering from acute medical or surgical illnesses and were considered at risk for nursing home placement were randomly assigned either to the geriatric assessment unit (n = 78) or to a control group that received usual care (n = 77). The two groups were similar at entry and were stratified according to the perceived risk of an immediate nursing home placement. After six months, the patients treated in the geriatric assessment unit had significantly more functional improvement in three of eight basic self-care activities (P less than 0.05). Those in the lower-risk stratum had significantly more improvement in seven of eight self-care activities. Both six weeks and six months after randomization, significantly more patients treated in the geriatric assessment unit than controls (79 vs. 61 percent after six months) were residing in the community. During the year of follow-up, the control patients had more nursing home stays of six months or longer (10 vs. 3; P less than 0.05). However, there was no difference between the groups in the mean number of days spent in health care facilities (acute care hospital, nursing home, or rehabilitation hospital). Survival analysis showed a trend toward fewer deaths among the patients treated in the geriatric assessment unit, and mortality was significantly reduced in the patients considered to be at lower risk of immediate nursing home placement (P less than 0.05). We conclude that the treatment of selected elderly patients in a specialized geriatric rehabilitation unit improves function, decreases the risk of nursing home placement, and may reduce mortality. The beneficial effects on mortality and function appear greatest for patients at a moderate rather than high risk of nursing home placement.     

Association between cytochrome P450 (CYP) 2C19 polymorphisms and harm avoidance in Japanese.

Polymorphic enzyme cytochrome P450 (CYP) 2C19 is expressed not only in the liver but also in the brain and mediates the biotransformation of 5-hydroxytriptamine (5-HT). We investigated possible association between genetic polymorphism of CYP2C19 and individual personality traits, possibly influenced by neurotransmitters. Mentally and physically healthy Japanese subjects were enrolled in this study (n = 352). Temperament and Character Inventory (TCI) and CYP2C19 genotyping were performed in all subjects. We detected CYP2C19*2 and *3 (http://www.imm.ki.se/CYPalleles/) using Amplichip CYP450 DNA tip. The number of genotypes classified as homozygous extensive metabolizer (EM), heterozygous EM, and poor metabolizer were 113, 181, and 58, respectively. Significant difference was found in TCI score in harm avoidance (HA; F = 3.138, P < 0.05). Post hoc analysis showed that TCI score in harm avoidance in homozygous EM was significantly lower than that in heterozygous EM (P < 0.05) or PM (P < 0.05). In sub-item analyses, HA3 (shyness with strangers, P < 0.01) and HA1 (anticipatory worry, P < 0.05) of TCI scores were significantly different among CYP2C19 genotypes. Meanwhile, there were no differences in TCI scores of novelty seeking (NS; F = 0.350, n.s.), reward dependence (RD; F = 1.080, n.s.), or persistence (P; F = 0.786, n.s.) among CYP2C19 genotypes. This study demonstrated that a significant association between CYP2C19 activity and HA is present in Japanese.     

Reliability of the transcutaneous PO2 measurement in the adult by the TCM 1 radiometer electrode

The accuracy of transcutaneous PO2 measurements (PtcO2; Radiometer TCM 1) was evaluated by comparison with arterial PO2 (PaO2) on 115 recordings in 35 patients: 20 during exercise testing (group I) and 14 during assisted ventilation at different FIO2 values (group II). The correlation coefficient between PaO2 and PtcO2 was satisfactory (r = 0.977; n = 115). However PaO2 and PtcO2 mean values were significantly different in group I, and in group II at 45% FIO2. The analysis of variance showed that the difference between PaO2 and PtcO2 was significant among the patients but did not vary with exercise and FIO2 changes (group I: F19 = 6.28, p less than 0.001; group II: F19(19) = 2.54, p less than 0.025). In the adult, transcutaneous PO2 measurement by TCM 1 radiometer electrode seems to be interesting in the context of monitoring blood gases with exercise and assisted ventilation. The significant variation with arterial PO2 sometimes registered should make one cautious in the interpretation of accurate measurements.     

重组促红细胞生成素对血透患者NO的影响研究

目的 :探讨基因重组促红细胞生成素 (rHuEpo)对维持性血透患者血管活性介质一氧化氮 (NO)的影响。方法 :将长期规律性血透尿毒症患者 80例分为血液透析应用rHuEpo者 (HDepo组n =4 3例 ) ,血液透析不应用rHuEpo者 (HD组n =37例 ) ,根据血压情况两组再分为HDepo高血压亚组 (HDepo - 1组 ,n =2 3)、HDe po血压正常亚组 (HDepo - 2组 ,n =2 0 )和HD高血压亚组 (HD - 1组 ,n =19)、HD血压正常亚组 (HD - 2组 ,n =18)。另选尿毒症未透析患者 2 0例 (NHD组 )、原发性高血压患者 2 0例、健康对照组 35例 (CON组 )。HDepo组患者均接受rHuEpo治疗 3个月以上 ,用比色法测定血NO水平。结果 :尿毒症未透析患者血清NO水平明显高于正常对照组 ,p <0 0 0 1;尿毒症透析患者血清NO浓度较正常对照组高 ,p <0 0 0 1,但经透析治疗的尿毒症患者与尿毒症未透析者比较 ,血清NO水平较未透析者低 ,p <0 0 5 ;HDepo组经rHuEpo治疗三月后血NO浓度下降 ,与用药前及对照组比较 ,p<0 0 0 1,p <0 0 5。且用rHuEpo治疗后 ,HDepo组收缩压、舒张压、平均动脉压均较HD组高 ,p <0 0 0 1,血压增高与NO浓度的降低有相关性。结论 :rHuEpo可使尿毒症透析患者血NO浓度降低 ,rHuEpo致高血压与血NO浓度降低有一定的关系     

Polymorphism of complement C3 in chronic inflammatory bowel disease. Predominance of the C3F gene in Crohn's disease

Polymorphism of the third component of complement (C3), occupying a key position in cascade reactions, was investigated in 125 consecutive outpatients, 53 with Crohn's disease and 72 with ulcerative colitis. A sample of 1378 randomly selected healthy volunteers of Danish origin served as controls. Occurrence of the F and FS phenotype of C3 (C3F and C3FS ) was increased in the group of Crohn's disease patients (chi 2 = 2.80, p less than 0.05, one-tailed test) and in a subgroup of Crohn patients with the gastrointestinal disease process confined to ileum (chi 2 = 6.91, p less than 0.01). C3 phenotype distribution was unaffected in ulcerative colitis. Only S and F alleles of C3 ( C3S and C3F) were recognized and C3F frequencies were 0.33 in Crohn patients with small bowel disease, 0.23 in all Crohn patients, 0.18 in ulcerative colitis patients and 0.17 in healthy volunteers. The results are compatible with a positive association of the C3F gene and Crohn's disease located in the small bowel.     

The Saccharomyces cerevisiae aldose reductase is implied in the metabolism of methylglyoxal in response to stress conditions

The enzyme aldose reductase plays an important role in the osmo-protection mechanism of diverse organisms. Here, we show that yeast aldose reductase is encoded by the GRE3 gene. Expression of GRE3 is carbon-source independent and up-regulated by different stress conditions, such as NaCl, H2O2, 39 degrees C and carbon starvation. Measurements of enzyme activity and intracellular sorbitol in wild-type cells also indicate that yeast aldose reductase is stress-regulated. Overexpression of GRE3 increases methylglyoxal tolerance in Saccharomyces cerevisiae. Furthermore, high expression of GRE3 complements the deficiency of the glyoxalase system of a glo1delta mutant strain. Consistent with this, in vitro and in vivo assays of yeast aldose reductase activity indicate that methylglyoxal is an endogenous substrate of aldose reductase. Furthermore, addition of NaCl or H2O2 to exponential-phase cells triggers an initial transient increase in the intracellular level of methylglyoxal, which is dependent on the Gre3p and Glo1p function. These observations indicate that the metabolism of methylglyoxal is stimulated under stress conditions; and they support a methylglyoxal degradative pathway, in which this compound is metabolised by the action of aldose reductase.     

Increased regional cerebral glucose uptake in an APP/PS1 model of Alzheimer's disease

Alzheimer's disease (AD), the most common age-related neurodegenerative disorder, is characterized by the invariant cerebral accumulation of β-amyloid peptide. This event occurs early in the disease process. In humans, [18F]-fluoro-2-deoxy-D-glucose ([18F]-FDG) positron emission tomography (PET) is largely used to follow-up in vivo cerebral glucose utilization (CGU) and brain metabolism modifications associated with the Alzheimer's disease pathology. Here, [18F]-FDG positron emission tomography was used to study age-related changes of cerebral glucose utilization under resting conditions in 3-, 6-, and 12-month-old APP(SweLon)/PS1(M146L), a mouse model of amyloidosis. We showed an age-dependent increase of glucose uptake in several brain regions of APP/PS1 mice but not in control animals and a higher [18F]-FDG uptake in the cortex and the hippocampus of 12-month-old APP/PS1 mice as compared with age-matched control mice. We then developed a method of 3-D microscopic autoradiography to evaluate glucose uptake at the level of amyloid plaques and showed an increased glucose uptake close to the plaques rather than in amyloid-free cerebral tissues. These data suggest a macroscopic and microscopic reorganization of glucose uptake in relation to cerebral amyloidosis.     

The role of aldose reductase inhibition in diabetic neutrophil phagocytosis and killing.

This study examines whether an aldose reductase inhibitor (statil, ICI) can enhance neutrophil oxidative killing by diabetic neutrophils. We have examined a radiometric assay of phagocytosis and killing of Candida albicans by neutrophils from 20 controls and 20 subjects with insulin-dependent diabetes under various in vitro glucose concentrations. Glucose was present at 5, 10 and 20 mM in the presence and absence of statil (11 microM). Phagocytosis was unaffected by raised glucose levels in controls and in diabetic subjects. Killing by the diabetic cells was inhibited by increasing concentrations of glucose, killing was 18.9 +/- 2.0, 16.9 +/- 2.4 and 14.8 +/- 2.0% (mean +/- s.e.m.) at 5, 10 and 20 mM glucose, respectively (P less than 0.05). With the addition of statil under the same conditions killing improved to 19.3 +/- 2.0, 23.2 +/- 2.2 and 23.6 +/- 2.4 (P less than 0.01), these values were similar to the controls (P greater than 0.01). We conclude therefore that aldose reductase inhibition restores oxidative killing to normal.     

Serum resistance in Escherichia coli strains causing acute pyelonephritis and bacteraemia.

The capacity of Escherichia coli to resist the bactericidal action of serum was examined in 367 clinical isolates obtained from children with acute pyelonephritis (n = 57), adults with acute pyelonephritis (n = 55), non-diabetic patients with bacteraemia (n = 101), diabetic patients with bacteraemia (n = 65) and from the faecal flora of healthy controls (n = 89). The incidence of serum-resistant E. coli strains was significantly higher in pyelonephritogenic strains from children and adults (93% and 82%) as compared to faecal control strains (57%, p less than 0.001 and p less than 0.005 respectively). Strains causing bacteraemia in non-diabetic and diabetic patients were more often serum resistant (72% and 80%) as compared to control strains (p less than 0.05 and p less than 0.001 respectively). The frequency of serum-sensitive strains was similar in diabetic patients with decreased renal function or proteinuria compared to those with normal renal function. There were no significant correlations between serum resistance of E. coli and expression of P fimbriae, type I fimbriae or mannose-resistant haemagglutination, cell surface hydrophobic properties, production of aerobactin, haemolysin or cytotoxic necrotizing factor in 53 pyelonephritogenic strains from adult patients.     

Calcium and phosphorus levels in serum and CSF in dementia

Marked differences in CSF levels of both calcium and phosphorus were observed in patients with dementia and aged controls when compared with adult controls. A significant decrease in both Ca and P in CSF was observed in Alzheimer's type dementia (p less than 0.01) and multi-infarct dementia cases (p less than 0.01). The geriatric controls also showed a significant decrease in both Ca and P. A 60% decrease in diffusible Ca in CSF was noted both in patients and geriatric controls when compared to adult controls (p less than 0.001). Diffusible P was also decreased in all three groups (p less than 0.05). A marginal decrease in serum Ca and slight increase in P was observed in both patients and geriatric controls. The significant decrease in CSF Ca and P in both groups of patients compared with aged controls suggests this lowering of Ca and P is not due to solely to the aging process and indicates a role in the pathology of age-related disorders.     

Effects of dietary taurine supplementation or deprivation in aged male Fischer 344 rats

Taurine is a sulfur amino acid that is present in high concentration in mammalian tissues and previously has been reported to decline in a number of tissues with advancing age. The aims of the present study were to examine: (1) the effects of dietary taurine supplementation; (2) the effects of taurine-free diets; (3) the ability of aged rats to conserve urinary taurine; and (4) the consequences of these dietary manipulations on some biochemical parameters. Male F344 rats (n = 30/group) 18 months of age were placed on control diets, diets supplemented with 1.5% taurine in the drinking water, or a taurine-free diet for 10 months. An adult control group (12 months old at the end of the study) on normal diets was included for comparison purposes. Significant (P < 0.05) age-related declines in taurine content were observed in the spleen, kidney, eye, cerebellum and serum. Taurine supplementation corrected these deficits in tissue content in aged rats and in many cases increased taurine content above that of adult controls. Urinary excretion of taurine was significantly (P < 0.05) reduced in aged rats indicating an increased need to conserve taurine. Taurine-deficient diets did not further exacerbate the age-related decline in tissue taurine content, suggesting biosynthetic adaptations to the lack of dietary taurine. Dietary taurine supplementation blunted age-related declines in serum IGF-1 and increases in serum creatinine and blood urinary nitrogen (BUN). These studies suggest that advanced aging results in a taurine-deficient state that can be corrected by dietary supplementation.     

Autonomic and peripheral nerve function in early diabetic neuropathy. Possible influence of a novel aldose reductase inhibitor on autonomic function

Autonomic and peripheral nerve functions as well as the possible short-term effect of a novel aldose reductase inhibitor (ARI) on neuropathy were evaluated in 30 male type I diabetics (age 25-44 years, mean 34; duration of diabetes 10-20 years, mean 34) with neurographic signs of peripheral neuropathy (PN). Autonomic neuropathy (AN) was established by the heart rate reactions to deep breathing (E/I ratio = vagal function) and to tilt (acceleration index = sympathetic and vagal functions; the brake index = vagal function). Twenty-nine patients, 13 with AN, completed the study. Among neurographic variables, only sural nerve function tests correlated with autonomic functions. Patients with AN showed significantly lower mean sensory action potential amplitudes (SAPA) sural, indicating axonal losses, than patients without AN (3.58 +/- 0.79 microV v. 7.34 +/- 1.12 microV; p less than 0.01). PN as measured by neurography did not improve during ARI treatment. On the other hand, vagal function (brake indices) improved (p less than 0.05) during ARI in AN patients.