氯沙坦对D-半乳糖致衰老大鼠肾脏肾小管上皮细胞转分化的影响

目的:探讨D-半乳糖致衰老大鼠肾脏中是否存在肾小管上皮细胞转分化及血管紧张素受体拮抗剂氯沙坦对其的影响。方法:大鼠随机分为3组:对照组、模型组、治疗组,每组12只。D-半乳糖连续腹腔注射制作亚急性衰老模型。观察肾组织病理改变,免疫组化方法检测α-平滑肌肌动蛋白(α-SMA)、增殖性细胞核抗原(PCNA)的表达。结果:模型组肾小球体积增大,局灶节段性肾小球硬化,肾小管腔扩大,灶状小管萎缩,间质纤维化,而治疗组肾组织改变与模型组相比有所减轻。模型组α-SMA、PCNA的表达较对照组明显升高,而治疗组α-SMA、PCNA的水平较模型组减低(P<0.05)。结论:氯沙坦可以抑制α-SMA、PCNA的表达,抑制小管上皮细胞转分化,抑制细胞外基质的积聚,从而减轻衰老。     

Beneficial effects of water-based exercise in patients with chronic kidney disease

The possible beneficial effect of regular aquatic exercise on cardiorespiratory, renal lipid parameters and oxidative stress status was studied in patients with mild to moderate renal failure. The exercise group did low-intensity aerobic exercise in the pool during a period of 12 weeks, twice a week, with sessions lasting for 30 min. Matched control participants remained sedentary. The results showed that in the exercise group all cardiorespiratory functional parameters improved and resting blood pressure lowered significantly. Proteinuria and cystatin-C were diminished significantly and glomerular filtration rate was enhanced. To evaluate the changes in oxidative stress status in the serum, products of lipid peroxidation (LPO) and serum glutathione values were measured. LPO was reduced significantly and reduced glutathione levels showed significant improvement after the exercise-conditioning programme. In the control group the data either remained the same or worsened in the same period of time. In conclusion, regular water-based exercise has beneficial effects on the cardiorespiratory, renal functional parameters and oxidative stress status in patients with moderate renal failure, and can be used in the complex rehabilitation of chronic renal failure patients, together with blood pressure control, dietary consultation, encouragement and education to prevent physical worsening and to postpone cardiovascular and renal atherosclerotic complications.     

Serotonin transporter occupancy in rats exposed to serotonin reuptake inhibitors in utero or via breast milk

Rigorous data regarding fetal central nervous system (CNS) exposure after antidepressant exposure are sparse. The magnitude of serotonin reuptake inhibitor (SRI) CNS exposure was measured in three groups of rats using ex vivo autoradiography of the serotonin transporter (SERT): 1) in utero, 2) postnatal clearance after birth, and 3) exposure through lactation. Rats were exposed to one of five SRI-type antidepressants (escitalopram, fluoxetine, paroxetine, sertraline, and venlafaxine) administered continuously via osmotic minipumps to pregnant or nursing dams. Dam dosing was adjusted to reflect the 50th and 85th percentiles of serum concentrations observed in pregnant women. Embryonic day 21 rat pups exposed in utero exhibited >80% SERT occupancy in brain tissue, which is equivalent to that of the pregnant dam and similar to that reported for human pharmacotherapy. Venlafaxine was the exception with occupancies ranging from 61 to 92% across different litters. The magnitude of SERT occupancy is essentially equivalent between dams and fetuses. By postnatal day 4, high SERT occupancy was observed only in fluoxetine-exposed pups (41-92% occupancy). Significantly less, but measurable, exposure occurred via breast milk exposure even in the absence of detectable drug concentrations in nursing pup sera. Pups exposed to SRIs via breast milk for 3 or 7 days exhibited varying SERT occupancies (0-57% depending on the individual medication and dam dose). These data highlight the need for animal modeling of fetal and nursing infant drug exposure using clinically meaningful dosing strategies and appropriate CNS measures to develop rational treatment guidelines that systematically minimize fetal and neonatal medication exposure in humans.     

Alteration in the glutathione,glutathione peroxidase,superoxide dismutase and lipid peroxidation by ascorbic acid in the skin of mice exposed to fractionated gamma radiation

BACKGROUND: In spite of the immense therapeutic gains produced by the fractionated irradiation (IR) regimen, radiation burden on the skin increases significantly. Protection of skin might enable use of higher radiation doses for better therapeutic gains. Ascorbic acid (AA), an essential ingredient of the human diet, is known to be a free radical scavenger and radioprotective agent. This study was undertaken to evaluate the effect of ascorbic acid on the radiation-induced changes in the status of glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD) and lipid peroxidation (LPx) in the skin of mice exposed to 10, 16 and 20 Gy of fractionated gamma radiation. METHODS: One group of the animals was administered daily with double distilled water (DDW), while the other group received 250 mg/kg b. wt. of ascorbic acid once daily, consecutively for 5, 8 or 10 days, before hemibody (below rib cage) exposure to 2 Gy/day of gamma-rays. Skin biopsies from both the groups were collected for the biochemical estimations. RESULTS: The irradiation of animals resulted in a dose-dependent decline in the activities of superoxide dismutase, glutathione peroxidase and glutathione contents. Ascorbic acid pretreatment resulted in a significant increase in the activities of both the enzymes and glutathione in the irradiated mouse skin. Normal concentrations of glutathione could not be restored even by day 6 post-irradiation. Conversely, lipid peroxidation increased in a dose-dependent manner in both the groups reaching a peak concentration by 3 h post-irradiation, while the ascorbic acid pretreatment inhibited the radiation-induced increase in lipid peroxidation. CONCLUSIONS: The ascorbic acid treatment arrested the decline in the activities of superoxide dismutase and glutathione peroxidase, glutathione contents and inhibited the radiation-induced lipid peroxidation in the skin of mice exposed to different doses of fractionated gamma radiation.     

促红细胞生成素干预肾缺血再灌注损伤后肾小管间质的纤维化

背景：促红细胞生成素能减轻炎症反应、抗凋亡以及对缺血再灌注肾损伤有保护性作用。目的：分析促红细胞生成素对肾缺血再灌注损伤后细胞凋亡和肾小管间质纤维化的关系。方法：通过单侧肾缺血再灌注损伤构建患侧肾小管间质纤维化模型。实验小鼠随机分为4组：假手术组、缺血再灌注组、促红细胞生成素低剂量组和促红细胞生成素高剂量组。苏木精-伊红、Masson染色观察肾脏病理改变,免疫组织化学检测肾组织中Bcl-2和Bax蛋白表达水平,Western blot检测Caspase-3的表达。结果与结论：与缺血再灌注组相比,两促红细胞生成素干预组肾小管和间质病变减轻。缺血再灌注组和两促红细胞生成素干预组肾脏Bcl-2和Bax表达均较假手术组明显上调,但缺血再灌注组更明显;缺血再灌注组Bcl-2/Bax比值较假手术组低,而两促红细胞生成素干预组Bcl-2/Bax比值却较缺血再灌注组高;两促红细胞生成素干预组Caspase-3表达高于假手术组而低于缺血再灌注组。结果表明,肾缺血再灌注损伤后期肾小管间质纤维化进程与细胞凋亡相关,Bcl-2/Bax及Caspase-3起了重要作用;低剂量促红细胞生成素也能减轻小鼠肾缺血再灌注损伤后期肾小管间质纤维化程度。     

Functional loading tests in nephropathy examination in patients recovering from hemorrhagic fever with renal syndrome

AIM: To characterize nephropathy in patients recovering after hemorrhagic fever with renal syndrome (HFRS) using functional loading tests. MATERIALS AND METHODS: In 65 HFRS convalescents we examined renal function under water deprivation, exercises and studied intraglomerular hemodynamics. RESULTS: After 2-month follow-up renal functional reserve was absent in 34% of the convalescents indicating intraglomerular hypertension. Under water deprivation most of the patients showed persistent tubulointerstitial disorders. Submaximal muscular exercises aggravated glomerular and tubular dysfunction manifesting with microalbuminuria, increased excretory beta 2-microglobulin fraction, low concentration reserve. CONCLUSION: Functional loading tests provide more detailed characterization of renal function in HFRS convalescents.     

Prevention of Vascular Apoptosis in Myocardial Infarction by Losartan

BACKGROUND: Previous studies have demonstrated the occurrence of apoptosis in cardiomyocytes in different types of cardiovascular diseases. This report provides the first evidence for the presence of vascular apoptosis in myocardial infarction induced in rats by occluding the coronary artery for 7 weeks. METHODS AND RESULTS: Apoptosis was characterized by DNA fragmentation, upregulation of caspase-3, downregulation of poly (ADP-ribose) polymerase (PARP), increased c-fos mRNA expression and caspase-3/PARP ratio in aortic vascular smooth muscle cells. The results show apoptotic changes in 10-25% of the aortic vascular cells after myocardial infarction; these alterations were prevented after treating the 3-week operated animals with an angiotensin II receptor antagonist, losartan (25 mg/kg/day; intraperitoneal) for 4 weeks. Cultured rat aortic smooth muscle cells exposed to 10 nmol/L angiotensin II for 48 hours also exhibited apoptotic changes, which were inhibited by 10 nmol/L losartan. CONCLUSIONS: These results suggest that vascular apoptosis occurs in myocardial infarction, and this may be due to an increase in the circulating levels of angiotensin II.     

Effects of ethanol ingestion on maternal and fetal glucose homeostasis

Carbohydrate metabolism has been studied in the offspring of rats fed liquid diet containing ethanol during gestation (EF group). Weight-matched control dams were given liquid diet either by the pair-fed technique (PF group) or ad libitum (AF group). EF and PF dams showed reduced food consumption and attenuated gain in body weight during the gestation period compared with the AF group. Blood glucose, liver glycogen, and plasma insulin levels were significantly reduced in EF and PF dams. Ethanol ingestion resulted in a significant decrease in litter survival and fetal body weight. At term, EF pups on average showed a 30% decrease in blood glucose levels and 40% decrease in plasma insulin levels compared with AF pups. One hour after birth, EF pups exhibited a marked increase in blood sugar level compared with either control group; subsequently, there was a marked decrease in blood glucose levels in EF pups. Liver glycogen stores were significantly reduced in term EF fetuses and were mobilized more rapidly in EF neonates than in either control group. Fetal hyperinsulinemia disappeared shortly after delivery in control pups, as expected; however, in EF pups, the fall in plasma insulin level was gradual. Fetal and neonatal plasma glucagon levels were not altered by ethanol exposure in utero. Blood glucose levels remained significantly low at 2 days of age in EF pups, but reached near control values at 4 days of age. Plasma insulin and glucagon were nearly equal in EF and control pups at 2 and 4 days of age. These results show aberrations in blood glucose, plasma insulin, and liver glycogen levels in offspring exposed to ethanol in utero.     

单侧输尿管梗阻模型大鼠肾间质纤维化过程中血小板衍生生长因子D的表达

背景：血小板衍生生长因子在肾间质中通过诱导肾小管间质细胞增生、表型转化、炎性细胞浸润等导致肾小管间质纤维化。目的：观察血小板衍生生长因子D在单侧输尿管梗阻模型大鼠肾脏组织中的表达水平及随时间的演变情况。方法：将成年健康雄性SD大鼠60只随机分为模型组及假手术组,将模型组大鼠左侧输尿管结扎剪断建立单侧输尿管梗阻模型,假手术组大鼠不结扎剪断仅游离左侧输尿管。术后3,7,14,21,28d,通过免疫组化检测血小板衍生生长因子D在肾脏组织中的表达分布情况,实时荧光定量RT-PCR方法检测血小板衍生生长因子D mRNA的表达水平及变化。结果与结论：假手术组血小板衍生生长因子D仅少量表达于肾小球系膜细胞及血管平滑肌细胞,而在模型组,血小板衍生生长因子D同时表达于肾间质纤维化区域,随纤维化程度加重,表达增多。同时模型组血小板衍生生长因子D mRNA表达量较假手术组显著增多（P〈0.05）,且表达随时间延长逐渐增多。提示血小板衍生生长因子D在单侧输尿管梗阻模型肾间质纤维化过程中发挥着促纤维化的重要意义。     

Chronic tubulointerstitial nephritis and renal insufficiency associated with long-term "subtherapeutic" gentamicin

To determine whether long-term "subtherapeutic" concentrations of aminoglycoside produce chronic tubulointerstitial nephropathy, Fisher rats were given gentamicin, 20 mg/kg/day, for up to 6 months via indwelling osmotic infusion pumps. Studies included renal histology, autoradiographic quantitation of renal cell tritiated thymidine uptake, renal function and renal cortical gentamicin assay. Acute proximal tubular injury, without tubular necrosis, followed by recovery, occurred during the first month. Subsequently only mild, nonprogressive tubulointerstitial changes and a twofold increase in tubular cell turnover were observed. Inulin clearance fell more than 50% during the 6 months of treatment compared with 10% in age-matched controls. Serum creatinine and creatinine clearance overestimated glomerular filtration rate during treatment and did not distinguish treated animals from controls. During the month after 6 months of gentamicin, tubular microcystic changes and active tubulointerstitial nephritis developed, with a continued fall in inulin clearance. In summary, gentamicin, in "subtherapeutic" doses, produces mild chronic tubulointerstitial nephritis with progressive renal failure. Cessation of treatment is associated with microcystic and inflammatory changes, suggesting that the renal response to tubular injury can be dissociated from the amount of toxin in the renal cortex. Keeping serum aminoglycoside levels below accepted therapeutic range for 6 months did not preclude nephrotoxicity.     

Effect of angiotensin convertase inhibitors and AT1 angiotensin receptor antagonists on the development of oxidative stress in the kidney of diabetic rats.

The aim of this study was to analyse the effect of angiotensin convertase inhibitor, enalapril (ENA), and angiotensin AT-1 receptor antagonist, losartan potassium (LP), on lipid peroxidation and activities of Cu,Zn-superoxide dismutase, catalase and glutathione peroxidase in kidneys of streptozotocin (STZ)-induced diabetic rats after 6 and 12 weeks of treatment. STZ-induced body weight changes and blood glucose concentration were not affected by either ENA or LP but both drugs significantly decreased cholesterol and triglyceride concentrations elevated in diabetic rats, inhibited kidney weight gain, and decreased albuminuria. Kidneys of STZ-diabetic rats had increased malondialdehyde content and decreased activities of antioxidant enzymes (Cu,Zn-superoxide dismutase, catalase and glutathione peroxidase). Both ENA and LP decreased lipid peroxidation and augmented the activities of antioxidant enzymes studied in the kidneys of diabetic rats. These results confirm the role of oxidative stress in the development of diabetic nephropathy already at early stages of the development of diabetes and point to the possible antioxidative mechanism of the nephroprotective action of ENA and LP.     

TLR ligand decreases mesenteric ischemia and reperfusion injury-induced gut damage through TNF-alpha signaling

Ischemic gut contributes to the development of sepsis and organ failure in critically ill patients. Toll-like receptors (TLRs) have been reported to mediate the pathophysiology of organ damage following ischemia/reperfusion (I/R) injury. We hypothesize that LPS, a ligand for TLR4, decreases mesenteric I/R injury-induced gut damage through tumor necrosis factor alpha (TNF-alpha) signaling. First, wild-type (WT) mice were fed with oral antibiotics for 4 weeks to deplete the intestinal commensal microflora. At week 3, drinking water was supplemented with LPS (10 microg/microL) to trigger TLRs. The intestinal mucosa was harvested for TLR4 protein, caspase 3 activity, and terminal deoxynucleotide transferase labeling assay. Second, WT and Tnfrsf1a mice received 30-min ischemia and 30-min reperfusion (30I-30R) or 30I-180R of the intestine; intestinal permeability and lipid peroxidation of the intestine were examined. Third, WT and Tnfrsf1a mice were fed with oral antibiotics with or without LPS and received 30I-180R of the intestine. The intestinal mucosa was harvested for lipid peroxidation; glutathione (GSH) level; nuclear factor kappaB (NF-kappaB) and AP-1 DNA-binding activity; Bcl-w, TNF-alpha, and CXCR2 mRNA expression; and HSP70 protein assay. Commensal depletion increased caspase 3 activity as well as villi apoptosis and decreased TLR4 expression of the intestinal mucosa. LPS increased TLR4 expression and decreased villi apoptosis. Commensal depletion augmented 30I-180R-induced intestine permeability as well as lipid peroxidation and decreased GSH level in WT mice but not in Tnfrsf1a mice. LPS decreased 30I-180R-induced intestinal permeability as well as lipid peroxidation and increased GSH level of the intestinal mucosa in WT mice but not in Tnfrsf1a mice. Commensal depletion with 30I-180R increased NF-kappaB and AP-1 DNA-binding activity, HSP70 protein expression, and decreased Bcl-w and TNF-alpha mRNA expression of the intestinal mucosa in WT mice but not in Tnfrsf1a mice. Collectively, commensal microflora induces TLR4 expression and decreases apoptosis of the intestinal mucosa. Commensal depletion enhances I/R-induced gut damage. LPS prevents I/R-induced intestinal permeability, lipid peroxidation, and decrease in GSH level. Given that the preventive effect of LPS on I/R-induced gut damage and NF-kappaB activity of the intestine is abolished in Tnfrsf1a mice, we conclude that TLR ligand decreases mesenteric I/R injury-induced gut damage through TNF-alpha signaling.     

PTEN overexpression suppresses proliferation and differentiation and enhances apoptosis of the mouse mammary epithelium

The phosphatase PTEN regulates growth, adhesion, and apoptosis, among many other cell processes. To investigate its role during mouse mammary gland development, we generated MK-PTEN, a transgenic mouse model in which human PTEN is overexpressed in ductal and alveolar mammary epithelium during puberty, pregnancy, lactation, and involution. No obvious phenotype was observed in mammary tissue of pubescent virgin mice. However, MK-PTEN females could not lactate normally, and approximately 30% of pups died, with survivors exhibiting growth retardation. Transgenic offspring nursed by wild-type foster mothers, conversely, developed normally. This phenotype is consistent with a reduced number of alveolar epithelial cells due to a decrease in cell proliferation and an increase in apoptosis. Using mammary-enriched cDNA microarrays, we identified several genes that were preferentially expressed in MK-PTEN mammary tissue, including the IGF-binding protein-5 (Igfbp5) gene, and others whose expression was reduced, including the genes for c-Jun amino-terminal kinase. Secretory epithelial cell differentiation was impaired, as measured by the expression of specific milk protein genes. MK-PTEN mice also exhibited a 50% decrease in the phosphorylation state of Akt. Taken together, these results suggest that PTEN controls mammary gland development and, consequently, lactation.     

Expression of peroxisome proliferators-activated receptor gamma and alpha-smooth muscle actin in unilateral ureteral obstruction in rats]

OBJECTIVE: To evaluate the expression of peroxisome proliferators-activated receptor gamma (PPARgamma) and alpha-smooth muscle actin (alpha-SMA) in unilateral ureteral obstruction (UUO) in rats and the relationship between them and the extent of tubulointerstitial injury. METHODS: Male SD rats were randomly subjected to either left ureteral ligation (n=30) or sham operation (n=6), and they were sacrificed on 3, 7, 14, 21 or 28 days after UUO. Sections of renal tissue were stained with hematoxylin and eosin (HE), Masson, or periodic acid-silver methenamine (PASM). The extent of tubulointerstitial injury was determined by Banff classification. Immunohistochemical staining was performed to investigate the expression of PPARgamma and alpha-SMA in the renal tissue. RESULTS: Swelling of tubular epithelia cells, infiltration of inflammatory cells and proliferation of fibroblasts were not so obvious on days 3 and 7 after UUO. A diffuse inflammatory cells infiltration, and massive fibrous hyperplasia were detectable on days 14 and 21 after UUO. Most tubules showed serious damage and replaced by proliferative fibrous tissue on day 28. The expression of PPARgamma was almost undetectable in sham operation group. However, it was upregulated on day 3 and peaking on day 14, and then it was slightly decreased on days 21 and 28. The expression of alpha-SMA was only found in vascular smooth muscle cells in sham operation group. It was upregulated mainly in some interstitial cells on day 3 and increased with the progression of tubulointerstitial fibrosis. CONCLUSION: PPARgamma expression increases in rat renal tissue after UUO, but does not always correlate with the extent of the alpha-SMA expression and tubulointerstitial injury. These data suggest that increase in PPARgamma in renal tissue may play an important role in response to inflammation and fibrosis.     

Drug induced nephrotic syndrome

This review summarizes drug induced nephrotic syndrome. Major drugs which induce drug related nephrotoxicity are antibiotics, NSAID, radiocontrast media, anticancer drug and antirheumatic drug. Drug induced nephropathy can show various forms of renal diseases. The nephropathy consists of acute tubular necrosis, acute tubulointerstitial nephritis, pre-renal type renal failure, obstructive renal failure, chronic tubulointerstitial nephritis and glomerular damage. Major drugs which induce nephrotic syndrome and glomerular damage are gold, penicillamine, bucillamine and NSAID. In the nephrotic syndrome due to these drugs, the major type of renal disease is the membranous glomerulonephritis and the nephropathy resolves completely when the drug is withdrawn; renal function does not deteriorate, and corticosteroids are unnecessary.     

Effects of AT1 and AT2 receptor blockade on angiotensin II induced apoptosis of human renal proximal tubular epithelial cells

BACKGROUND: Tubular atrophy is a common histological feature of chronic renal failure, and epithelial cell death by apoptosis might play an important role in its pathogenesis. Angiotensin II contributes to the progressive nature of many kidney diseases and treatment with angiotensin converting enzyme inhibitors preserves the structure of the tubulointerstitial compartment in human and experimental renal diseases. METHODS: Primary cultures of human renal proximal tubular epithelial cells were co-incubated with angiotensin II alone or in combination with the angiotensin II AT1 receptor antagonist losartan or/and the AT2 antagonist PD123319. Apoptosis was determined after 20 hours by TUNEL staining and flow cytometry. RESULTS: Angiotensin II at concentrations of 10(-9) M induced apoptosis (control vs. angiotensin II 4 +/- 3% vs. 73 +/- 11%; p < 0.05). This effect was completely offset by co-incubation with the angiotensin II AT2 receptor blocker at concentrations 10(-7) M (control vs. PD123319 4 +/- 3% vs. 8 +/- 3%; p < 0.05); AT1 blockade was ineffective in apoptosis inhibition. When both angiotensin receptors were blocked, no additional effect on apoptosis inhibition could be detected. CONCLUSION: We provided evidence, that physiological concentrations of angiotensin II can induce apoptosis of human renal proximal tubule epithelial cells. This effect is mediated via AT2 receptors.     

Low molecular weight heparin protection against oxalate-induced oxidative renal insult

BACKGROUND: Oxidative stress has emerged as an invariable feature of calculogenesis, the process of stone formation. The cytoprotective action of low molecular weight heparin (LMWH) in calcium oxalate-induced oxidative renal injury in experimental calculogenesis was studied. METHODS: A renal membrane injury model involving gentamicin (40 mg/kg body weight) and 2% ammonium oxalate was used. Rats induced with gentamicin and ammonium oxalate were investigated for any impairment of cellular redox status as revealed by renal superoxide dismutase, catalase, glutathione peroxidase, xanthine oxidase activities and glutathione, ascorbate levels. In renal membrane protein activities such as aminotransferases in kidney and lactate dehydrogenase, total protein in urine of rats rendered lithogenic were assessed and compared with healthy vehicle-treated controls. The biochemical index of tissue lipid peroxidation was assessed in terms of malondialdehyde formation. LMWH was co-administered (250 microg/kg body weight) to gentamicin- and ammonium oxalate-dosed rats. RESULTS: The extent of oxidative damage was indicated by the increased lipid peroxidation in the renal tissues of gentamicin- and ammonium oxalate-administered groups. The decline in the antioxidative status of the stone forming kidneys further confirmed the oxidative stress to renal cells. The extensive nephritic damage in the form of proteinuria was quite evident and the injured status of the tissue was reflected in the significant alterations of the few membrane associated enzyme levels in urine and the kidney. LMWH restricted all the cyto-oxidative ill effects of ammonium oxalate and gentamicin. CONCLUSION: Low molecular weight heparin has antioxidant potential in countering the oxalate/calcium oxalate-mediated oxidative challenge in the experimental lithogenic model.     

Potentiation of lipid peroxidation in B16F10 and B16F1 melanoma cells by caffeine,a methylxanthine derivative: relationship to intracellular glutathione

BACKGROUND: Caffeine has shown an inhibitory role in invasion and proliferation in melanoma pulmonary metastasis as well as in high-grade tissue sarcoma. However, little is known about its mechanism and possible role in metastatic cell lines. MATERIALS AND METHODS: B16F10 and B16F1 cell lines of high and low metastatic potential were treated with caffeine at different time intervals with different doses. Reduced glutathione, glutathione S-transferase and lipid peroxides were estimated to evaluate the effect of caffeine. RESULTS: Caffeine treatment showed glutathione depletion and increased lipid peroxidation with higher glutathione S-transferase activity in both B16F10 and B16F1 cell lines. However the effect of caffeine was dependent on the time factor as well as on the dose. CONCLUSIONS: Caffeine was an effective inhibitor of metastatic activity. Glutathione depletion in conjunction with increased lipid peroxidation was a potent indicator in the regulation of metastatic behavior of B16F10 and B16F1 melanoma cell lines.     

Distribution of 2,4,5,2',4',5'-hexachlorobiphenyl among lipoproteins during pregnancy and lactation in the rat

The mechanism by which polychlorinated biphenyls are transferred from adipose tissue to the mammary gland during late pregnancy and lactation is unknown. Lipoproteins were investigated as a possible vehicle of transport. 2,4,5,2',4',5'-[14C] Hexachlorobiphenyl (6-CB) distribution among very low-, low- and high-density lipoproteins and the protein-rich bottom fraction was examined in virgin controls, in pregnant animals on days 9 and 18 of gestation, in mothers on day 10 of lactation and in suckling pups. Plasma obtained 1 hr after an i.v. injection of 6-CB was separated into the various lipoprotein fractions and their lipid composition analyzed. With advancing pregnancy, there was a shift in 6-CB distribution from the higher to lower density lipoproteins. A linear increase was observed in the amount of very low-density lipoprotein as well as the proportion of plasma 6-CB associated with it. Corresponding decreases occurred in the proportion of 6-CB associated with low-density lipoprotein and the bottom fraction. During late pregnancy, very low-density lipoprotein became the primary carrier of 6-CB in vivo. The pattern of 6-CB distribution among lipoproteins on day 10 of lactation resembled that on day 9 of pregnancy. Suckling pups exhibited the highest proportion of plasma 6-CB in low- and high-density lipoprotein. The shifts in the distribution of 6-CB during pregnancy and lactation were related to changes in the lipid constituents of plasma and the individual lipoproteins.