四氯化碳诱导大鼠肝纤维化脂质过氧化相关蛋白表达的动态变化及一贯煎的干预效应

目的 探讨四氯化碳(CCl4)诱导大鼠肝纤维化脂质过氧化相关蛋白表达的动态变化及一贯煎的干预效应.方法 Wistar雄性大鼠57只,其中模型组39只,正常组18只.模型大鼠腹腔注射50％的CCl4橄榄油溶液(1ml/lg),每周2次,共9周.造模3、6周后,随机抽取正常及模型大鼠各6只,处死作动态观察.其余模型大鼠随机分为模型组15只及干预组12只,模型组大鼠在8周时处死4只观察成模情况.第7周开始,继续造模的同时,干预组用一贯煎(2.682 g/kg)蒸馏水稀释灌胃,1次/d,共计3周.用药3周结束后,处死大鼠,检测肝功能、肝组织羟脯氨酸(Hyp)和丙二醛(MDA)含量、超氧化物歧化酶(SOD)与谷胱甘肽(GSH)活性,以及热休克蛋白70 (HSP70)、血红素加氧酶-1(HO-1)、转铁蛋白(Transferrin)、过氧化还原酶(Prxd)6、肝脏型脂肪酸结合蛋白(L-FABP)等的表达.计量资料采用单因素方差分析,计数资料采用Ridit分析. 结果 (1)与对照组比较,模型组大鼠6、9周时肝组织MDA含量显著升高[(4.23±0.45) nmol/mg比(2.22±0.59)nmol/mg; (6.29±1.23) nmol/mg比(2.22±0.59) nmol/mg,F值分别为60.13、66.99,P值均＜ 0.05];SOD活性显著降低[(196.94±39.20) U/mg比(264.50±30.44)U/mg,F=11.12,P＜ 0.05; (152.21±51.65) U/mg比(264.50±30.44) U/mg,F=23.11,P＜0.01];GSH含量显著降低[(48.47±7.27) nmol/mg比(60.74±9.04) nmol/mg,F=6.71,P＜0.05;(37.89±9.01) nmol/mg比(60.74±9.04)nmol/mg,F=24.06,P＜0.01];与9周模型组比较,干预组MDA显著降低[(4.25±0.86) nmol/mg比(6.29±1.23) nmol/mg,F=19.52,P＜ 0.01],SOD显著升高[(198.35±46.48) U/mg比(152.21±51.65) U/mg,F=4.65,P＜0.05],GSH显著升高[(53.73±7.54) nmol/mg比(37.89±9.01) nmol/mg,F=19.23,P＜0.01];(2)与正常组比较,9周时模型组大鼠HSP70蛋白表达量升高(1.21±0.06比0.58±0.07,F=166.87,P＜0.0l),HO-1蛋白表达量也升高(1.11±0.06比0.58±0.06,F=123.96,P＜ 0.01),Prdx6蛋白表达量降低(0.04±0.05比1.49±0.05,F=1215.85,P＜0.01),L-FABP表达量降低(0.24±0.02比1.44±0.14,F=219.05,P＜0.01),Transferrin蛋白表达量降低(0.67±0.03比1.67±0.04,F=301.35,P＜0.01).9周时,干预组HSP70和HO-1蛋白表达量分别为0.82±0.04、0.90±0.04,与9周时模型组比较,F值分别为92.31、26.89,P值均＜0.01,差异有统计学意义;9周时,干预组Prdx6、L-FABP和Transferrin蛋白表达分别为0.88±0.11、1.36±0.13、1.04±0.12,与9周时模型组比较,F值分别为150.17、237.19、27.53,P值均＜0.01,差异有统计学意义. 结论 一贯煎具有促进机体抗氧化物质生成、减轻脂质过氧化损伤的作用.     

Mineral metabolism in postmenopausal women with active rheumatoid arthritis

Serum and urinary variables of bone mineral metabolism were studied in 49 postmenopausal women with rheumatoid arthritis (RA). Results were compared to those in a sex, age and menopausal age matched control group. No patient took corticosteroids, or had any disease other than RA which might affect bone. Total serum calcium was low in patients with RA compared to controls (9.0 +/- 0.5 mg% vs 9.3 +/- 0.3 mg%, p less than 0.005), but was normal when corrected for albumin (9.5 +/- 0.6 mg% vs 9.3 +/- 0.4 mg%, NS). Serum phosphorus was significantly higher in patients with RA than in controls (3.6 +/- 0.3 mg% vs 3.3 +/- 0.4 mg%, p less than 0.001) as well as serum alkaline phosphatase activity (107.6 +/- 27.2 IU/l vs. 9.6 +/- 28.91 IU/l). Serum creatinine, vitamin D and parathyroid hormone levels were comparable in both groups. Urinary hydroxyproline and mucopolysaccharide excretions were higher in patients with RA than controls, both for fasting (respectively 0.089 +/- 0.028 vs 0.039 +/- 0.023, p less than 0.001 and 0.072 +/- 0.027 vs 0.047 +/- 0.019, p less than 0.001) and for 24 h values (50.3 +/- 17.9 mg vs 36.2 +/- 15.4 mg, p less than 0.001 and 54.6 +/- 26.0 mg vs 41.7 +/- 16.5 mg, p less than 0.05). Urinary calcium excretion was comparable in the 2 groups. Our findings of raised serum phosphorus and alkaline phosphatase activity, raised urinary hydroxyproline and mucopolysaccharides excretion suggest that in patients with RA there is a higher metabolic activity of bone. In none of the patients could any indication of osteomalacia or of parathyroid overactivity be found.     

Insulin receptor function and glycogen synthase activity in skeletal muscle biopsies from patients with insulin-dependent diabetes mellitus: effects of physical training

This study was designed to examine the mechanisms causing peripheral insulin resistance in patients with insulin-dependent diabetes mellitus (IDDM) by studying insulin receptor function and glycogen synthase activity in biopsies of skeletal muscle. The results in seven such patients were compared with values obtained in a group of sedentary, age- and sex-matched normal subjects. In addition, since physical training appears to improve insulin sensitivity, the IDDM patients were reexamined after physical training for 6 weeks. The mean maximal glycogen synthase activity was lower in the diabetic than in the normal group [34.5 +/- 10.6 (+/- SD) vs. 45.7 +/- 8.6 nmol/mg protein.min; P less than 0.05], whereas there was no difference in the half-maximal activation constant (A0.5) for glucose-6-phosphate. Likewise, the mean yield of wheat germ agglutinin-purified insulin receptors recovered per mg muscle was 21% lower in the muscle biopsies from the diabetic patients (47 +/- 8 vs. 66 +/- 20 fmol/100 mg; P less than 0.05. However, basal and insulin-stimulated receptor kinase activities, expressed as phosphorylation of the synthetic peptide poly-Glu-Tyr(4:1), were identical in the two groups. After physical training in the diabetic patients the mean maximal oxygen uptake increased from 45.7 +/- 7.4 to 48.9 +/- 9.0 mL O2/kg.min (P less than 0.05), hemoglobin A1c decreased from 7.9 +/- 1.4% to 7.7 +/- 1.5% (P less than 0.05), and insulin requirements decreased from 43 +/- 9 to 38 +/- 8 U/day (P less than 0.05). The number of recovered insulin receptors did not increase, and the receptor kinase activity was similar to the pre-training value. Maximal glycogen synthase activity increased by 15% (P less than 0.02), whereas A0.5 for glucose-6-phosphate did not change. We conclude that insulin binding to muscle-derived insulin receptors is impaired in IDDM patients, whereas receptor kinase function appears to be normal. The capacity for glycogen storage in the diabetic skeletal muscle was reduced. Physical training tended to normalize glycogen synthase activity, but did not improve insulin receptor function significantly.     

Effects of weight loss and weight maintenance on the serum lipids, lipoprotein lipase and hepatic triglyceride lipase activities in obese rats

The effects of obesity, weight loss and weight maintenance on the serum lipid levels and lipoprotein lipase and hepatic triglyceride lipase were investigated in rats. Obesity induced by high-fat (HF) feeding was associated with decreased serum triglyceride levels (HF: 70.3 +/- 8.2, control (CON): 140.0 +/- 26.9 mg/dl, P less than 0.05), increased lipoprotein lipase (LPL, HF: 593.2 +/- 10.6 vs CON: 280 +/- 19.5 nmol FFA/min per mg tissue, P less than 0.05) and suppressed hepatic triglyceride lipase activities (HTGL, HF: 14.2 +/- 0.5 vs CON: 18.0 +/- 0.4 nmol FFA/min per mg tissue, P less than 0.01). After a weight loss to the level of control rats, weight maintenance was achieved either by high-protein (HP) or chow feedings (CH). Both high-protein (HFHP) and chow (HFHC) groups had similar weights but only high-protein feeding restored the normal body compositions. Both groups of rats had higher total (TC, HFHP: 146 +/- 10.7; HFCH: 104.8 +/- 5.1 mg/dl), and high density lipoprotein cholesterol levels (HDL-C, HFHP: 100.8 +/- 15.6; HFCH: 75.5 +/- 5.5 mg/dl) and lower lipoprotein lipase (HFHP: 238.2 +/- 15.8, HFCH: 354.8 +/- 34.9 nmol FFA/min per mg tissue) and hepatic triglyceride activities (HFHP: 16.3 +/- 1.1; HFCH: 14.5 +/- 0.6 nmol FFA/min per mg tissue) than control rats (TC: 70.1 +/- 4.7 mg/dl; HDL-C: 14.2 +/- 4.3 mg/dl; LPL: 742.4 +/- 82.3 nmol FFA/min per mg tissue; HTGL: 20.5 +/- 1.0 nmol FFA/min per mg tissue, P less than 0.05 to 0.005) or the rats who regained weight by resuming high-fat feeding (TC: 59.5 +/- 6.7 mg/dl; HDL-C: 10.2 +/- 6.7 mg/dl; LPL: 1284.3 +/- 90 nmol FFA/min per mg tissue; HTGL: 22.2 +/- 1.9 nmol FFA/min per mg tissue, P less than 0.05 to 0.005). The high protein-group had significantly higher total and high-density-lipoprotein cholesterol levels than the chow fed animals despite comparable body weights in both groups. The findings of this study suggest that weight maintenance induced by high protein feeding is more successful in restoring the normal body composition. However, high protein feeding is also associated with high serum cholesterol levels. The clinical applications of these findings need to be evaluated further.     

Insulin and high glucose modulation of phosphatase and reductase enzymes in the human erythrocytes: a comparative analysis in normal and diabetic states

The ability of insulin to influence activities of various protein kinases and protein phosphatases, that are thought to mediate insulin action, are limited in patients with insulin resistance. Because numerous responses to insulin are affected, we undertook studies to determine whether protein tyrosine phosphatases (PTPs) activities are altered in patients with diabetes syndrome. In order to evaluate abnormal PTP activities, we done a comparative study using erythrocytes from normal and diabetic patients. We determined the activity of the cytosolic acid PTP in basal and insulin-dependent states. Mean basal PTP activities, were found to be significantly higher in diabetics than in normal subjects (type 1 diabetics: 0.36 +/- 0.01 vs 0.28 +/- 0.01 mmol p-nitrophenolate/h per g hemoglobin (Hb), P < 0.001; type 2 diabetics: 0.35 +/- 0.01 vs 0.28 +/- 0.01 mmol p-nitrophenolate/h per g Hb, P < 0.001). Insulin, at concentrations above physiological levels (1 mIU/ml), inhibited the PTP activities in erythrocytes from normal subjects (-15 +/- 4.1%, P < 0.01). Insulin could also modulate glycolysis, probably as a consequence of receptor tyrosine kinase activation, inducing phosphorylation of protein band 3 and hence the release of glycolytic enzymes. We have previously reported that a reductase enzyme in human erythrocytes is dependent on glycolysis being significantly activated (+28 +/- 3.1%, P < 0.001) by high insulin levels (1 mIU/ml). Mean basal reductase activities were found to be significantly lower in diabetics than in normal subjects (type 1 diabetics: 0.77 +/- 0.03 vs 0.97 +/- 0.02 mmol ferrocyanide/20 min per l cells, P < 0.001; type 2 diabetics: 0.77 +/- 0.04 vs 0.97 +/- 0.02 mmol ferrocyanide/20 min per l cells, P < 0.001), indicating altered erythrocyte metabolism in the diabetic patients. High glucose levels were used to mimic hyperglycemia condition, using erythrocytes from normal subjects. At 30 mM glucose, erythrocytic phosphatase activity was stimulated (+32 +/- 4.2%, P < 0.0001), although no effect was observed on the reductase enzyme at the same glucose levels. Results indicated that diabetic disorders appear to be associated with quantitative alterations of erythrocyte acid phosphatase activity and other enzymes that depend on the glycolytic rate (reductase). The overall data suggest that erythrocyte acid phosphatase may have a role in the modulation of glycolytic rates through the control of insulin receptor phosphorylation.     

Selective increase in cytochrome P450 content in hepatic microsomes from rats with ventromedial hypothalamic lesions

Changes in the components of hepatic microsomal electron transport systems and in drug hydroxylase activities were investigated in ventromedial hypothalamus (VMH) lesioned obese rats. Eight weeks after electrolysis of the bilateral VMH, the content of cytochrome P450 per mg microsomal protein (0.79 +/- 0.07 nmol/mg protein) was significantly higher (P less than 0.02) than that in the sham-operated rats (0.59 +/- 0.02). Cytochrome P450 per whole liver in the VMH-lesioned obese rats had also significantly increased (87 +/- 9 nmol vs 56 +/- 3, P less than 0.02). No significant differences were found in the cytochrome b5 contents, and the activities of NADPH- and NADH-cytochrome c reductases between the VMH-lesioned obese and sham-operated rats. The demethylation activities of aminopyrine (1.04 +/- 0.02 nmol/mg protein/min vs 0.94 +/- 0.02, P less than 0.05) and p-nitroanisole (0.96 +/- 0.02 vs 0.89 +/- 0.02 , p less than 0.02) and the aniline hydroxylase activity (0.22 +/- 0.01 vs 0.16 +/- 0.01, P less than 0.01) were enhanced, but 7-ethoxycoumarin O-deethylase activity was unchanged in the VMH-lesioned obese rats. These results indicate a selective increase in the content of cytochrome P450 among the components of the P450-dependent mixed function oxidase system in the liver of VMH-lesioned obese rats. Our observations suggest that drug metabolism may be enhanced in the hypothalamic obesity.     

Insulin and C-peptide plasma levels in patients with severe chronic pancreatitis and fasting normoglycemia

The aim of the present study was to evaluate insulin secretion by the pancreatic B cell in a group of patients with severe chronic pancreatitis and without overt diabetes. For this purpose we have measured plasma insulin and C-peptide peripheral levels in the fasting state and after a 100-g oral glucose load in 10 patients with severe chronic pancreatitis and fasting normoglycemia, and in 10 sex-, age-, and weight-matched healthy controls. As compared to normal subjects, patients with chronic pancreatitis showed: (1) significantly higher plasma glucose levels after oral glucose load (area under the plasma glucose curve 1708 +/- 142 vs 1208 +/- 47 mmol/liter X 240 min, P less than 0.005); (2) plasma insulin levels significantly higher at fasting (0.11 +/- 0.008 vs 0.08 +/- 0.005 nmol/liter, P less than 0.01) but not after oral glucose administration (area under the plasma insulin curve 79 +/- 12 vs 88 +/- 16 nmol/liter X 240 min); (3) significantly lower plasma C-peptide concentrations both in the fasting state (0.15 +/- 0.01 vs 0.54 +/- 0.05 nmol/liter, P less than 0.001) and after oral glucose load (area under the plasma C-peptide curve 211 +/- 30 vs 325 +/- 37 nmol/liter X 240 min, P less than 0.05). The finding of diminished plasma C-peptide levels suggests that chronic pancreatitis is associated with an impaired B-cell function even in the absence of overt diabetes. The increased or unchanged plasma insulin levels in spite of decreased plasma C-peptide concentrations indicate that in chronic pancreatitis insulin metabolism is reduced, most likely within the liver.     

Lactose digestion by human jejunal biopsies: the relationship between hydrolysis and absorption.

The relationship between lactose hydrolysis and absorption of released glucose was investigated by determining the kinetics of lactose digestion by jejunal biopsies incubated in vitro. Lactase activity in intact biopsies correlated with conventional assay of tissue homogenates (r = 0.85, p less than 0.001), and glucose uptake from 28 mM lactose was directly proportional to lactase activity (r = 0.95, p less than 0.001) in 21 subjects with normal lactase levels, six with hypolactasia (primary or secondary to coeliac disease) and two with lactose intolerance but normal lactase activity. Kinetic analysis at 0.56-56 mM lactose in five normal subjects showed saturable kinetics for hydrolysis (app Km = 33.9 +/- 2.2 mM; app Vmax = 26.5 +/- 1.1 nmol/min/mg dry weight) but glucose uptake could be fitted to a model either of saturable uptake (app Kt = 47.2 +/- 0.3 mM; app Jmax = 14.1 +/- 0.2 nmol/min/mg) or saturable uptake plus a linear component (app Kt = 21.3 +/- 1.15; app Jmax = 4.59 +/- 0.12; app Kd = 0.093 +/- 0.010 nmol/min/mg/mM). The proportion of glucose taken into the tissue did not significantly exceed 50% of the total released at any lactose concentration suggesting the lack of an efficient capture mechanism for the released glucose. The results suggest that lactose hydrolysis is the rate limiting step in the overall absorption of glucose from lactose in vitro, and that the relationship between hydrolysis and absorption is the same in normal subjects and in hypolactasic subjects.     

Low levels of gastric mucosal glutathione during upper gastric bleeding associated with the use of nonsteroidal anti-inflammatory drugs.

OBJECTIVES: To investigate the glutathione concentrations in gastric mucosa from patients with acute gastric bleeding related to nonsteroidal anti-inflammatory drugs (NSAIDs), and to test the influence of nutritional status on mucosal glutathione. Glutathione protects the gastrointestinal mucosa against reactive oxygen species, and glutathione content in various tissues may be depleted during malnutrition. METHODS: Endoscopic biopsies were obtained from 39 patients. Eighteen of these (9 well-nourished, 9 malnourished) presented with gastric bleeding ulcers related to NSAIDs. Twenty-one other patients (12 well-nourished, 9 malnourished) underwent normal routine diagnostic endoscopy and served as controls. Malnutrition was defined as a loss of over 10% of normal body weight and/or plasma albumin levels below 30 g/l. Gastric biopsies were taken from the fundus and antrum (controls) and from the region of the ulcer (patients with acute bleeding) and frozen quickly until glutathione analysis by high-performance liquid chromatography (HPLC) coulometric detection. Results were expressed as nmol/mg wet tissue. RESULTS: Gastric mucosal glutathione levels were significantly (P < 0.05) lower in both the antrum (0.81 +/- 0.34 v. 1.41 +/- 0.88 nmol/mg tissue) and the fundus (1.04 +/- 0.54 v. 1.43 +/- 0.92 nmol/mg tissue, P < 0.05) in malnourished than in well-nourished control patients. Glutathione mucosal concentrations were decreased significantly in patients with NSAID-induced gastric bleeding compared with control patients (0.38 +/- 0.36 v. 1.12 +/- 0.56 nmol/mg tissue, P < 0.001), and the lowest glutathione levels were observed in malnourished patients (0.28 +/- 0.20 v. 0.48 +/- 0.15 nmol/mg tissue in well-nourished patients, not significant). CONCLUSION: Malnutrition is associated with low levels of gastric glutathione. This may contribute to the severity and the onset of haemorrhage in NSAID-induced gastric ulcers.     

Defective myocardial carnitine metabolism in congestive heart failure secondary to dilated cardiomyopathy and to coronary, hypertensive and valvular heart diseases

Reduced myocardial carnitine concentrations in the explanted heart and elevated plasma levels have been found in patients undergoing heart transplant for end-stage congestive heart failure (CHF). To evaluate a possible loss of myocardial carnitine in less severe stages of CHF, total myocardial carnitine levels were compared in right ventricular endomyocardial biopsies from 28 patients with mild, moderate and severe dilated cardiomyopathy, 8 patients with CHF of different origin and 13 normal control subjects. If possible, free myocardial carnitine and free and total plasma carnitine were also determined. For the first time, myocardial carnitine levels have been measured in endomyocardial biopsies from 13 normal human hearts (control values: 9.9 +/- 0.8 nmol/mg noncollagen protein). In comparison with these control values, total myocardial carnitine was significantly reduced in patients with dilated cardiomyopathy (6.1 +/- 0.5 nmol/mg noncollagen protein, p less than 0.0001), and CHF of other origins (6.6 +/- 1.1 nmol/mg noncollagen protein, p less than 0.02). Free myocardial carnitine concentrations in dilated cardiomyopathy (4.6 +/- 0.4 nmol/mg noncollagen protein) and CHF of different origin (4.4 +/- 0.5 nmol/mg noncollagen protein) were also significantly different from control values (control values: 9.7 +/- 0.7 nmol/mg noncollagen protein, p less than 0.0001 and p less than 0.005 for both groups). The loss of free and total myocardial carnitine was comparable in dilated cardiomyopathy and CHF due to other diseases. In contrast, plasma free and total carnitine levels in the CHF patients were significantly elevated (67 +/- 5.5 mumol/liter, control values 41 +/- 3.7 mumol/liter, p less than 0.005). Alterations in myocardial carnitine metabolism represent nonspecific biochemical markers in CHF with yet unknown consequences for myocardial function.     

Adrenal androgens and illness

We have studied the adrenal androgen status of medically ill patients, patients before and after cholecystectomy and during recovery from burns injury. In patients ill for less than 2 weeks, serum androstenedione concentrations (mean +/- SEM) were raised (7.94 +/- 0.98 nmol/l) as compared with a control group (4.83 +/- 0.38 nmol/l, P less than 0.005) or with patients ill for more than 2 weeks (5.21 +/- 0.46 nmol/l, P less than 0.02); serum dehydroepiandrosterone sulphate (DHAS) levels were lower in patients ill for more than 2 weeks (1.21 +/- 0.42 mumol/l) than in either the acutely ill group (5.98 +/- 1.06 mumol/l, P less than 0.001) or the control ill group (5.56 +/- 0.59 mumol/l, P less than 0.001). In post-operative patients serum DHAS levels fell to below pre-operative levels reaching a nadir at day 8 (0.54 +/- 0.19 vs 1.66 +/- 0.56 mumol/l, P less than 0.02). In burned patients serum cortisol levels were increased on admission (661 +/- 91 vs 359 +/- 30 nmol/l, P less than 0.005) and remained high over the study period. Serum androstenedione concentrations were also high on admission (7.5 +/- 1.0 vs 3.9 +/- 0.3 nmol/l, P less than 0.02). Serum DHAS concentrations were similar to control values on admission (6.8 +/- 1.2 vs 5.2 +/- 0.7 mumol/l), fell to low levels thereafter reaching a nadir during week 3 (1.6 +/- 0.6 mumol/l, P less than 0.001). Steroid synthesis in times of chronic illness may be diverted from adrenal androgen to corticosteroid pathways ensuring maintained secretion of cortisol, which is essential to the health of ill patients.     

Carnitine status, plasma lipid profiles, and exercise capacity of dialysis patients: effects of a submaximal exercise program

Carnitine status, blood lipid profiles, and exercise capacity were evaluated in a combined group of hemodialysis (N = 4) and continuous ambulatory peritoneal dialysis (N = 6) patients before and after an 8-week submaximal exercise program. Maximal aerobic capacity (VO2max) was only 18.5 +/- 5.9 (mean +/- SD) mL O2/kg/min, well below the expected 30 to 35 mL O2/kg/min for age-matched sedentary controls. Plasma short-chain acylated carnitine levels, which were two to three times normal values, were reduced after the exercise program, but the long-chain acylcarnitines were significantly reduced during acute exercise. Muscle biopsies of the vastus lateralis were performed at rest in five patients prior to and after the 8-week exercise program. Total carnitine in skeletal muscle was 3.09 (.076 SD) mumol/g ww, with only 11.3% acylated prior to the exercise program, which was much lower than the 4.25 +/- 1.27 mumol/g ww, with 28.5% acylated in a group of healthy athletic subjects (N = 28). Muscle free carnitine concentrations decreased significantly following the 8-week training period, with only a slight reduction in total carnitine. The percent of acylated carnitine was therefore significantly increased (P less than 0.05) from 11.3% to 25.2% after the experimental period. Pretraining carnitine palmitoyl transferase activity at rest was 0.57 +/- 0.28 nmol palmitoyl carnitine formed/5 min/mg mitochondrial protein, which was not changed by exercise training v 1.80 +/- 0.51 nmol/5 min/mg protein in 28 healthy normals (P less than 0.001). Free fatty acid concentrations were reduced significantly during acute exercise as a result of the exercise training program whereas other plasma lipids were not altered. (ABSTRACT TRUNCATED AT 250 WORDS)     

Endoscopic measurement of oesophageal transmucosal potential difference in reflux oesophagitis.

Oesophageal transmucosal potential difference (PD) was measured in 76 patients during endoscopy. Twelve patients with no symptoms of gastro-oesophageal reflux, and normal oesophageal appearance on endoscopy and mucosal biopsy had a PD of -18.3 +/- 3.8 mV (mean +/- SD). Thirty three patients had reflux symptoms but the oesophagus appeared normal at endoscopy. Eighteen of these patients had reflux change on oesophageal suction biopsies and the PD in the same region of the oesophagus in this group was -18.1 +/- 7.5 mV. In 15 of the patients, mucosal biopsies were normal and the PD in this group was -18.8 +/- 9.9 mV. Thirty one patients had erosive oesophagitis and PD values in this group were markedly reduced. Twenty seven of these patients had PD values less than -10 mV. We conclude that PD measured by our technique is abnormal in erosive oesophagitis but that it is of no value in the diagnosis of mild mucosal damage in patients with reflux symptoms when endoscopic findings are normal.     

Alterations of the adrenocorticotropin-cortisol axis in normal weight bulimic women: evidence for a central mechanism

We studied pituitary-adrenal function in eight women with normal weight bulimia and seven normal women by measuring plasma ACTH and serum cortisol levels at 20-min intervals for 24 h and the responses to human CRH (hCRH) and to a noon meal. The bulimic women had increased 24-h transverse mean plasma ACTH [1.09 +/- 0.06 (+/- SE) vs. 0.75 +/- 0.14 pmol/L; P less than 0.05] and serum cortisol (235 +/- 21 vs. 152 +/- 9 nmol/L; P less than 0.005) concentrations. While the 24-h ACTH and cortisol pulse frequencies were unaltered, the bulimic women had higher (P less than 0.05) mean peak ACTH (1.46 +/- 0.09 vs. 1.03 +/- 0.15 pmol/L) and cortisol values (331 +/- 33 vs. 239 +/- 17 nmol/L). Despite having higher mean and peak plasma ACTH and serum cortisol values, the bulimic women had a blunted response of both ACTH (P less than 0.001) and cortisol (P less than 0.005) to hCRH, which included a lower mean maximal plasma ACTH response, decreased (P less than 0.05) integrated area under the ACTH response curve (161 +/- 12 vs. 231 +/- 23 pmol/min.L), a lower (P less than 0.05) maximum cortisol response (284 +/- 35 vs. 413 +/- 19 nmol/L), and decreased (P less than 0.05) area under the cortisol curve (11.1 +/- 1.9 vs. 15.9 +/- 1.3 X 10(3) nmol/min.L). The circadian variations of both ACTH and cortisol were maintained in the bulimic women; the nadir and acrophase times were similar to those of the normal women. However, the rise in serum cortisol that occurred within 1 h after the lunch meal in the normal women (104 +/- 35 nmol) did not occur in the bulimic women (P less than 0.05). These data demonstrate that marked changes in hypothalamic-pituitary-adrenal function occur in bulimia in the absence of weight disturbance and suggest central activation of CRH and/or synergistic factors as well as alterations in signals from gut to brain in this syndrome.     

Lipid peroxidation and antioxidant enzyme levels in type 2 diabetics with microvascular complications

Serum levels of total cholesterol, triglycerides, lipoproteins, lipid peroxides (TBARS) and erythrocyte antioxidant enzyme activities were measured in 105 non insulin dependent diabetic patients, among whom 38 had microvascular complications (MVC) of diabetes. All the diabetic patients had higher concentrations of glycated hemoglobin (HbA1) compared to controls (10.51 +/- 2.42% vs 6.31 +/- 0.85% P <0.001). Significant increase of serum triglycerides (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (VLDL-C) and a significant decrease of high density lipoprotein cholesterol (HDL-C) were observed in the diabetic patients compared to controls (TG: 2.31 +/- 0.9 mmol/l vs 1.53 +/- 0.48 mmol/l P <0. 001; TC: 5.94 +/- 1.4 mmol/l vs 4.3 +/- 0.85 mmol/l P <0.001; LDL-C: 3.96 +/- 1.33 mmol/l vs 2.39 +/- 0.8 mmol/l P <0.001; VLDL-C: 0.46 +/- 0.2 mmol/l vs 0.3 +/- 0.09 mmol/l P <0.001; HDL-C: 0.81 +/- 0.24 mmol/l vs 1.04 +/- 0.18 mmol/l P <0.001). Significantly increased levels of serum TBARS were observed in diabetic patients compared to those in controls (TBARS: 6.7 +/- 1.5 mmol/l vs 5.14 +/- 0.61 mmol/l P <0.001). Erythrocyte catalase (CAT) activity was increased and Glutathione peroxidase (GPx) activity was decreased in diabetic patients compared to controls, but no significant change in Superoxide dismutase (SOD) activity was observed in diabetic patients (CAT: 104.94 +/- 37.1 KU/g Hb vs 85.8 +/- 23.6 KU/g Hb, P <0.01; GPx: 30 +/- 9.7 U/g Hb/min vs 40.84 +/- 12.3 U/g Hb/min, P <0. 001; SOD: 2.4 +/- 1.2 U/mg Hb/min vs 2.55 +/- 0.84 U/mg Hb/min, P=NS). In comparison with the diabetic group without MVC, the diabetic group with MVC had decreased GPx and SOD activities, while no difference was observed between these two groups regarding CAT activity (GPx: 25.32 +/- 8.4 U/g Hb/min vs 34.5 +/- 8.8 U/g Hb/min, P <0.001; SOD: 1.83 +/- 0.53 U/mg Hb/min vs 2.84 +/- 1.4 U/mg Hb/min, P<0.001; CAT: 106.3 +/- 39.9 KU/g Hb vs 103 +/- 34.9 KU/g Hb, P =NS). TBARS concentrations were significantly increased in the group with MVC compared to the group without these complications, indicating a positive relationship between TBARS and MVC of diabetes (7.05 +/- 1.23 mmol/l vs 6.3 +/- 1.02 mmol/l, P <0.001). Serum triglycerides, LDL and VLDL cholesterol concentration were significantly higher in diabetics with MVC than in diabetics without the complications (TG: 2.7 +/- 0.98 mmol/l vs 2.13 +/- 0.82 mmol/l, P<0.01; LDL - C: 4.45 +/- 1.3 mmol/l vs 3.67 +/- 1.3 mmol/l, P <0. 02; VLDL-C: 0.53 +/- 0.19 mmol/l vs 0.43 +/- 0.16 mmol/l, P <0.01), and the serum levels of TC in the group with MVC showed a positive correlation with their lipid peroxide levels (r =0.368, P <0.001). The increase in TBARS and the decreased GPx and SOD activities in diabetics with MVC in this study indicate that these factors may contribute to the occurrence of micro vascular complications in NIDDM patients.     

Acid cholesteryl ester hydrolase activity of mononuclear leukocytes in patients with non-insulin-dependent diabetes mellitus: studies before and after treatment of diabetes.

The change of acid cholesteryl ester hydrolase activity in mononuclear leukocyte following treatment of diabetes mellitus was studied in 21 patients with non-insulin-dependent diabetes mellitus (NIDDM). Enzyme activity before treatment in the patients was significantly lower than that in 14 age-matched healthy subjects (1.20 +/- 0.15; mean +/- S.E. vs. 2.20 +/- 0.17 nmol/mg protein/h, P less than 0.01). Enzyme activity before treatment in the patients was significantly increased (P less than 0.05) after 4-8 weeks of treatment. However, enzyme activity of 1.43 +/- 0.14 nmol/mg protein/h observed after treatment in the patients was significantly lower (P less than 0.01) than that in the healthy subjects. There was a significant negative correlation between enzyme activity before treatment and the increase in enzyme activity following treatment (rs = -0.555, P less than 0.01, n = 21). These results indicate that low level of enzyme activity may be insufficiently improved by the treatment of diabetes, and the risk for the development of atherosclerosis as viewed from the enzyme activity may persist even after the treatment in NIDDM.     

Coproporphyrinogen oxidase, protoporphyrinogen oxidase and ferrochelatase activities in human liver biopsies with special reference to alcoholic liver disease

The activities of coproporphyrinogen oxidase, protoporphyrinogen oxidase and ferrochelatase have been assayed in human liver biopsies using recently developed highly sensitive specific enzyme assays. The specific activities (nmol/min/mg protein) in controls were 0.010 +/- 0.003 (mean +/- S.D., n = 11), 0.18 +/- 0.07 (n = 9) and 0.062 +/- 0.022 (n = 8), respectively. The total activities (mumol/min/liver) were determined, using ultrasound to determine liver volumes, and were 2.6 +/- 0.6 (n = 5), 36.6 +/- 13.9 (n = 6) and 14.2 +/- 5.4 (n = 3), respectively. Both specific and total enzyme activities in alcoholics with fatty liver were not significantly different from normal controls. Decreased protoporphyrinogen oxidase activity (0.08 nmol/min/mg protein or 20.2 mumol/min/liver) was found in two patients with variegate porphyria. In a patient with erythrohepatic protoporphyria a reduction of the ferrochelatase activity (0.01 nmol/min/mg protein) was demonstrated.     

Continuous subcutaneous insulin infusion therapy decreases insulin resistance in type 1 diabetes

The influence of continuous sc insulin infusion therapy for 6 weeks on sensitivity to insulin (euglycemic clamp technique) and hepatic glucose production (3-[3H]glucose technique) was measured in 10 type 1 diabetic patients whose mean duration of diabetes was 8 yr. Mean diurnal blood glucose fell from 8.5 +/- 0.8 (SEM) mmol/liter to 6.0 +/- 0.6 mmol/liter (P less than 0.05) and glycosylated hemoglobin from 10.5 +/- 0.4% to 8.7 +/- 0.3%. Insulin requirements declined by 23% from 47 +/- 4 U/day prepump to 36 +/- 2 U/day after 6 weeks of pump therapy (P less than 0.01). During the insulin clamp, plasma insulin was maintained at approximately 90 mU/liter and plasma glucose at approximately 5.0 mmol/liter in all studies. The rate of glucose metabolism in diabetic patients during conventional therapy (4.65 +/- 0.41 mg/kg X min) was 35% lower than in normal subjects (7.20 +/- 0.42 mg/kg X min, n = 14, P less than 0.001). After 6 weeks of pump therapy, total glucose uptake increased by 27% to 5.90 +/- 0.60 mg/kg X min, P less than 0.05 vs. prepump). This was still 18% lower than in the normal subjects (P less than 0.05). Basal hepatic glucose production in the diabetic patients during conventional therapy (3.07 +/- 0.14 mg/kg X min) was 70% higher than in the normal subjects (1.79 +/- 0.07 mg/kg X min, n = 7, P less than 0.001). After 6 weeks of pump therapy, hepatic glucose production fell to 2.48 +/- 0.19 mg/kg X min (P less than 0.05), which was still 40% higher than in the normal subjects (P less than 0.01). Basal hepatic glucose production was directly related to the fasting plasma glucose level (r = 0.67, P less than 0.001) and inversely proportional to fasting insulin concentration (r = -0.48, P less than 0.05) in the diabetic patients. Specific tracer insulin binding to erythrocytes in the diabetic patients (19.4 +/- 1.5%) was comparable to that in the normal subjects (19.6 +/- 1.2%) and remained unchanged during pump therapy. Thus the improved metabolic control resulting from pump therapy is associated with enhancement in sensitivity to insulin, and reduction in basal hepatic glucose production.     

Relationship between insulin sensitivity, insulin secretion and glucose tolerance in cirrhosis

Hepatic insulin extraction is difficult to measure in humans; as a result, the interrelationship between defective insulin secretion and insulin insensitivity in the pathogenesis of glucose intolerance in cirrhosis remains unclear. To reassess this we used recombinant human C-peptide to measure C-peptide clearance in cirrhotic patients and controls and thus derive C-peptide and insulin secretion rates after a 75-gm oral glucose load and during a 10 mmol/L hyperglycemic clamp. Cirrhotic patients were confirmed as insulin-insensitive during a euglycemic clamp (glucose requirement: 4.1 +/- 0.1 mg/kg/min vs. 8.1 +/- 0.5 mg/kg/min; p less than 0.001), which also demonstrated a low insulin metabolic clearance rate (p less than 0.001). Although intolerant after oral glucose, the cirrhotic patients had glucose requirements identical to those of controls during the hyperglycemic clamp (cirrhotic patients: 6.1 +/- 1.0 mg/kg/min; controls: 6.3 +/- 0.7 mg/kg/min), suggesting normal intravenous glucose tolerance. C-peptide MCR was identical in cirrhotic patients (2.93 +/- 0.16 ml/min/kg) and controls (2.96 +/- 0.24 ml/min/kg). Insulin secretion was higher in cirrhotic patients, both fasting (2.13 +/- 0.26 U/hr vs. 1.09 +/- 0.10 U/hr; p less than 0.001) and from min 30 to 90 of the hyperglycemic clamp (5.22 +/- 0.70 U/hr vs. 2.85 +/- 0.22 U/hr; p less than 0.001). However, with oral glucose the rise in serum C-peptide concentration was relatively delayed, and the insulin secretion index (secretion/area under 3-hr glucose curve) was not elevated. Hepatic insulin extraction was reduced both in fasting and during the hyperglycemic clamp (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)