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Biomedical subjects

V Gross

Publications and source records attributed to V Gross.

At least 37 records · Page 2Linked to original sources
PubMed2002

[Dependence of nocturnal bronchial obstruction on sleep position].

Patients with bronchial obstructions often have problems to stay asleep at night. The interaction between sleep position and bronchial obstructions has not been investigated until now. A total of 20 patients was included in this study. All patients were recorded one night in our sleep laboratory with a parallel recording of lung sounds using a commercial Pulmotrack 1010 system. The bronchial obstructions were lower in lateral position than in supine position for both tracheal and chest sounds (p = 0,083 and p = 0,036; n.s.). This effect seemed to be especially high in patients with many obstruction episodes. From our results we can conclude that there is a small dependence of bronchial obstructions from sleep position. Further investigations are needed to verify this result.

Adult↗
PubMed2001

Clinical and histopathological features of dextran sulfate sodium induced acute and chronic colitis associated with dysplasia in rats.

We examined the clinical and histopathological features of the dextran sulfate sodium (DSS) induced acute and chronic colitis in rats as a model for studying basic biology of the inflamed colonic mucosa. Acute colitis was induced in male Wistar rats by 4 days (AI) or 7 days (AII) of oral 5% (wt/vol) DSS (mol. wt. 54,000) in their drinking water. Chronic colitis was induced in 8 experimental groups: CI=7 days DSS followed by 10 days water (=one cycle); CII=two cycles; CIII to CVIII (three to eight cycles) received only 4 days 5% DSS followed by 10 days drinking water. The entire colons were examined histologically; dysplasia was graded as: indefinite/probably negative for dysplasia, indefinite/probably positive for dysplasia, low-grade dysplasia, or high-grade dysplasia. The earliest clinical findings in the acute colitis group over 4 days occurred on day 2 (hemoccult positive stools, loose stools or diarrhea and weight loss). The maximal disease activity was noted on day 7 accompanied by a 53% mortality rate. The histological inflammation scores were significantly higher on day 7 than on day 4. All rats had extensive ulcerations predominantly in the rectum and cecum. The number of rats having ulcerations was markedly lower in the chronic colitis groups. The majority (75%) of the crypt lesions suspicious for dysplasia were classified as mucosa indefinite/probably negative for dysplasia. We classified 18 crypt lesions as low-grade dysplasia and one lesion as high-grade dysplasia (after eight cycles). No invasive carcinoma was observed. Most low-grade dysplasias (83%) occurred after five cycles of DSS/water, located mostly in the rectum (44%) and colon transversum (33%). Our findings suggest that the DSS colitis model in rats may be an interesting model for studying the sequence chronic inflammation-dysplasia in human ulcerative colitis. Further long-term studies with the present DSS colitis model in rats might also prove it as a reliable model to study the sequence high-grade dysplasia and colitis associated-cancer.

Acute Disease↗
PubMed2001

Interrelationship between insulin, leptin and growth hormone in growth hormone-treated children.

OBJECTIVES: The aim of the study was to examine insulin homeostasis during growth hormone (GH) therapy, and to investigate the effect of GH treatment on insulin and leptin concentration in obese children. SUBJECTS: Nineteen obese children (8 with Prader-Willi Syndrome (PWS)) were treated with GH 0.1 IU/kg/day dose for 3 months and were compared with 29 non-treated age and sex matched obese children (9 PWS) and 49 GH treated non-obese short children. Mean age of the children was 10.3+/-1.8 (6.7-13.8) y, with body mass index of 23.6+/-10.4 (11.5-47) kg/m2. RESULTS: Leptin concentration decreased and was correlated inversely with initial leptin value (r2=-0.374, P<0.001) and decreased body mass (r2=0.338, P=0.001). Insulin sensitivity index was not significantly changed during therapy. Leptin decrease after 3 months of GH administration was correlated inversely with the increase in first phase insulin response to intravenous glucose tolerance test (IVGTT) (r2=-0.595, P<0.001). Results of long-term follow-up of treated patients demonstrated a decrease in insulin concentration after cessation of therapy. In GH-treated subjects, the glucose increase in response to glucose load appeared to be higher than in untreated subjects. CONCLUSION: The high insulin response to glucose load seen in GH-treated subjects was appropriate to their glucose concentration and the insulin sensitivity index was unchanged relative to the pretreatment period. Increased insulin dosage in our patients did not induce an increase in leptin concentrations as had been hypothesised.

Anthropometry↗
PubMed2001

Left ventricular function in mice lacking the AT2 receptor.

OBJECTIVES: The role of the AT2 receptor in the heart is incompletely understood. We investigated left ventricular performance in AT2 receptor knockout mice, with and without deoxycorticosterone acetate (DOCA)-salt treatment. Given the putative opposing functions of the AT1 and AT2 receptor, we also analysed AT1 receptor expression in the left ventricle. METHODS: We used a miniaturized conductance-manometer system to measure pressure-volume loops for analysing left ventricular performance under baseline conditions and after increasing peripheral vascular resistance. We determined left ventricular AT1-receptor expression by RNase-protection assays. RESULTS: In AT2 receptor knockout mice, end-systolic and end-diastolic volumes were lower than in wild-type mice, so that pressure-volume loops were shifted leftward. Left ventricular systolic and diastolic kinetics were not different between the groups. AT2 receptor knockout mice and wild-type mice both stabilized their reduced stroke volume after laparatomy as peripheral resistance was increased. DOCA-salt treatment increased elastance in AT2 receptor knockout mice, compared to controls. Furthermore, AT2 receptor knockout mice had a steeper increase in dP/dtmax. Left ventricular AT1 receptor gene expression was increased in AT2 receptor knockout mice and was not down-regulated in response to DOCA-salt treatment. Finally, the hearts of AT2 receptor knockout mice were smaller than controls, but increased in size in response to DOCA-salt treatment. CONCLUSIONS: AT2 receptor knockout mice displayed no major changes in left ventricular function at baseline or in response to DOCA-salt treatment, compared to wild-type mice. The AT2 receptor may be important to AT1 receptor expression in response to DOCA-salt challenge and may have some influence on cardiac growth responses.

Animals↗
PubMed2001

Association of HLA-DR genotypes and IL-1ra gene polymorphism with treatment failure of budesonide and disease patterns in Crohn's disease.

OBJECTIVE: Associations between HLA-DR genotypes and susceptibility to Crohn's disease (CD) have been reported. However, it is not known whether certain HLA-DR genotypes or IL-1ra gene polymorphism are associated with responsiveness to treatment or different clinical patterns of disease. DESIGN/SETTING: In a large, randomized, controlled multicentre trial, 318 patients with CD were treated with daily doses of 6, 9 or 18 mg budesonide. Patients were stratified into two groups: patients without steroid pretreatment and with active CD (CDAI > 150) and patients with conventional steroid pretreatment of < or= 30 mg prednisolone per day, which was replaced by oral budesonide within 3 weeks. MAIN OUTCOME MEASURES: The HLA-DRB1 genotypes 1-16 and the IL-1ra gene polymorphism were examined for an association with budesonide treatment failure. RESULTS: Only HLA-DR 8 was associated with treatment failure of budesonide. HLA-DR 8 is not very common. Only 17/243 patients who could be evaluated expressed this genotype, and 13 of these 17 patients did not respond to budesonide (P < 0.00067). Neither the other HLA-DR genotypes nor the IL-1ra gene polymorphism had an influence on treatment outcome of budesonide therapy. No significant association of fistulas, perianal disease, need for bowel resections, and disease localization with certain HLA-DRB1 genotypes or the IL-1ra gene polymorphism were found. CONCLUSIONS: This is the first description of an association of a certain HLA-DR genotype (HLA-DR 8) with treatment failure in inflammatory bowel disease (IBD).

Adult↗
PubMed2001

Normal blood pressure and renal function in mice lacking the bradykinin B(2) receptor.

Telemetric blood pressure determinations, heart rate measurements, and pressure-natriuresis-diuresis experiments were used to characterize cardiovascular and renal function in bradykinin B(2) receptor knockout mice fed mouse chow containing 0.25% NaCl or mouse chow containing 4% NaCl. In B(2) receptor knockout mice fed usual mouse chow, the mean arterial blood pressure leveled between 108+/-1 and 110+/-3 mm Hg, and the heart rate leveled between 520+/-26 and 525+/-29 bpm, values that were not different from those measured in B(1) receptor knockout mice or 129Sv/J control mice. Increasing dietary salt intake did not affect mean arterial blood pressure and heart rate. Accordingly, pressure-natriuresis curves, pressure-diuresis curves, renal blood flow, and glomerular filtration rate were not different between B(2) receptor knockout and 129Sv/J mice. Increasing dietary salt intake to 4% increased renal blood flow to levels between 8.41 and 9.50 mL/min per gram kidney wet weight in 129Sv/J mice, whereas in B(2) receptor-deficient mice, renal blood flow was not affected and ranged between 6.85 and 7.88 mL/min per gram kidney wet weight. Other renal function parameters were not affected. Absence of B(2) receptor function was verified in B(2) receptor knockout mice with bradykinin infusion. These data suggest that the absence of B(2) receptor function does not necessarily make B(2) receptor knockout mice hypertensive or induce salt sensitivity. Presumably, differences in the genetic background or an adaptation to the loss of B(2) receptor function may account for these results, in contrast with earlier reports involving B(2) receptor knockout mice. We hold the latter possibility to be more likely and to be a fruitful possibility for future research.

Animals↗
PubMed2001

Expression analysis using oligonucleotide microarrays in mice lacking bradykinin type 2 receptors.

We recently conducted detailed cardiovascular and blood pressure-related phenotypic studies of mice lacking the bradykinin-B(2) receptor and were unable to identify a phenotype despite insensitivity to infused bradykinin. We therefore used oligonucleotide microarray analysis of some 12 000 genes and expressed sequence tags to identify molecular mechanisms that might be involved in compensating for the lack of a functional B(2) receptor in the kidneys of the mice. We identified 2 gene families that may have an impact on cardiovascular regulation and the bradykinin pathway. A water transport channel in the kidney, AQP4, was downregulated in the mice, whereas other members of the gene family did not show differences in expression levels. In addition, a number of serine proteases were upregulated in B(2) receptor-deficient mice. These genes are all located within a gene cluster on mouse chromosome 7. The findings were verified by an independent method. We suggest that microarray analysis has usefulness in elucidating otherwise unappreciated compensatory signaling pathways.

Animals↗
PubMed2001

Vacuolating megalencephalic leukoencephalopathy in 12 Israeli patients.

Leukodystrophy with macrocephaly as the main features of infantile neurodegenerative disease are characteristics of Canavan's disease, L-2-hydroxyglutaric aciduria, type I glutaric aciduria, and Alexander's disease. Also occasionally described are occidental congenital muscular dystrophy, G(M)2-gangliosidosis, metachromatic leukodystrophy, Krabbe's disease, and mucopolysaccharidosis. Since 1995, over 60 patients with a new syndrome, vacuolating megalencephalic leukoencephalopathy, have been described. The syndrome is characterized by macrocephaly, a slowly progressive clinical course of ataxia, spastic paraparesis, and seizure disorder with relatively spared cognition. Unlike other leukodystrophies with macrocephaly (except Alexander's disease), no metabolic marker has been found. We describe a similar group of 12 patients from two different Jewish ethnic origins in whom consanguinity is prominent. These patients have neuroimaging features and magnetic resonance spectroscopy findings indicating that there is an initial increase in white-matter edema with subsequent cystic formation. Consistent with loss of tissue in these areas, brain metabolites are reduced. The familial incidence in this group of patients is suggestive of autosomal-recessive inheritance.

Adolescent↗
PubMed2000

Normal blood pressure and plasma renin activity in mice lacking the renin-binding protein, a cellular renin inhibitor.

In renal extracts, some renin is present as "high molecular weight renin," a heterodimeric complex of renin with the 46-kDa renin-binding protein (RnBP), also known as N-acyl-D-glucosamine 2-epimerase. Because RnBP specifically inhibits renin activity, the protein was proposed to play an important role in the regulation of the renin-angiotensin system (RAS). Using gene targeting, we have generated mice lacking RnBP and tested this hypothesis in vivo. In particular, we analyzed biosynthesis, secretion, and activity of renin and other components of the RAS in mice lacking RnBP. Despite extensive investigations, we were unable to detect any major effects of RnBP deficiency on the plasma and renal RAS or on blood pressure regulation. Contrary to previous hypotheses, we conclude that RnBP does not play a significant role in the regulation of renin activity in plasma or kidney. However, RnBP knockout mice excrete an abnormal pattern of carbohydrates in the urine, indicating a role of the protein in renal carbohydrate metabolism.

Animals↗
PubMed2000

Prophylaxis of postoperative relapse in Crohn's disease with mesalamine: European Cooperative Crohn's Disease Study VI.

BACKGROUND & AIMS: This study investigated if long-term treatment with high-dose mesalamine reduces the risk of clinical relapse of Crohn's disease after surgical resection. METHODS: In a prospective, randomized, double-blind, multicenter study, 4 g of mesalamine (Pentasa; Ferring A/S, Vanlose, Denmark) daily was compared with placebo in 318 patients. Treatment was started within 10 days after resective surgery and continued for 18 months. Primary outcome parameter was clinical relapse as defined by an increase in Crohn's Disease Activity Index, reoperation, septic complication, or newly developed fistula. Risk factors for recurrence were prospectively defined to be analyzed in a stepwise proportional hazards model. RESULTS: Cumulative relapse rates (+/-SE) after 18 months were 24.5% +/- 3.6% and 31.4% +/- 3.7% in the mesalamine (n = 152) and placebo (n = 166) groups, respectively (P = 0.10, log-rank test, 1-sided). Retrospective analysis showed a significantly reduced relapse rate with mesalamine only in a subgroup of patients with isolated small bowel disease (n = 124; 21.8% +/- 5.6% vs. 39.7% +/- 6.1%; P = 0.02, log-rank test). Probability of relapse was predominantly influenced by the duration of disease (P = 0.0006) and steroid intake before surgery (additional risk, P = 0.0003). CONCLUSIONS: Eighteen months of mesalamine, 4 g daily, did not significantly affect the postoperative course of Crohn's disease. Some relapse-preventing effect was found in patients with isolated small bowel disease.

Adult↗
PubMed2000

Inhibition of pressure natriuresis in mice lacking the AT2 receptor.

UNLABELLED: Inhibition of pressure natriuresis in mice lacking the AT2 receptor. BACKGROUND: Angiotensin II type 2 (AT2) receptor knockout mice have higher blood pressures than wild-type mice; however, the hypertension is imperfectly defined. We tested the hypothesis that renal mechanisms could be contributory. METHODS: We conducted pressure-natriuresis-diuresis experiments, measured renal cortical and medullary blood flow by laser Doppler methods, and explored cytochrome P450-dependent arachidonic acid metabolism by means of reverse transcription-polymerase chain reaction. RESULTS: Blood pressure was 15 mm Hg higher in AT2 receptor knockout mice than in controls, and pressure diuresis and natriuresis curves were shifted rightward. At similar renal perfusion pressures (113 to 118 mm Hg), wild-type mice excreted threefold more sodium and water than AT2 receptor knockout mice. Fractional sodium and water excretion curves were shifted rightward in parallel. Renal blood flow ranged between 6.72 and 7.88 mL/min/g kidney wet weight (kwt) in wild-type and between 5.84 and 6.15 mL/min/g kwt in AT2 receptor knockout mice. Renal vascular resistance was increased in AT2A receptor knockout mice. Cortical blood flow readings leveled at 2.5 V in wild-type and 1.5 V in AT2 receptor knockout mice. Medullary blood flow readings ranged between 0.8 and 1.0 V and increased 116% in wild-type mice as renal perfusion pressure was increased. This increase did not occur in AT2 receptor knockout mice. The glomerular filtration rate (GFR) was similar in both groups at approximately 1 mL/min/g kwt. Renal microsomes from AT2 receptor knockout mice had less activity in hydroxylating arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-meter) than controls, whereas renal AT1 receptor gene expression was increased in AT2 receptor knockout mice. CONCLUSIONS: Hemodynamic and tubular factors modify renal sodium handling in AT2 receptor knockout mice and may cause hypertension. AT2 receptor disruption induces alterations of other regulatory systems, including altered arachidonic acid metabolism, that may contribute to the intrarenal differences observed between AT2 receptor knockout and wild-type mice.

Angiotensin II↗
PubMed2000

Long-term blood pressure telemetry in AT2 receptor-disrupted mice.

OBJECTIVES: The hypertension in AT2 receptor knockout mice is imperfectly defined. Therefore, we investigated the influence of dietary salt loading and deoxycorticosterone (DOCA)-salt treatment on blood pressure and diurnal patterns of blood pressure in these mice by radiotelemetry. METHODS: We used telemetry in AT2 receptor knockout and wild-type mice to measure blood pressure, heart rate, aortic pressure dp/dt, locomotor activity, and circadian rhythms. Salt-related effects were studied by increasing the salt in chow to 4%, adding 1% saline in drinking water, and by DOCA-salt treatment RESULTS: Baseline blood pressures were higher in AT2 receptor knockout than in wild-type mice and were not affected by increasing the salt intake. The blood pressure increase was steeper and greater in AT2 receptor knockout than in wild-type mice after DOCA-salt treatment A circadian rhythm of blood pressure and heart rate, with higher values during the night, was seen in wild-type, but not in AT2 receptor knockout mice. In AT2 receptor knockout mice, this rhythm was only significant when daily salt intake was increased or when DOCA-salt hypertension was induced. The acrophase of blood pressure and heart rate was found between 2000 and 2400 h and was in accordance with the maximum physical activity. CONCLUSION: These data suggest that AT2 knockout mice display slight hypertension which is not salt-sensitive. On the other hand, the susceptibility to develop DOCA-salt hypertension is increased. The study also illustrates the power of telemetry in monitoring long-term cardiovascular changes and circadian blood pressure and heart rate rhythms in genetically engineered mice.

Animals↗
PubMed2000

The role of the resident intestinal flora in acute and chronic dextran sulfate sodium-induced colitis in mice.

OBJECTIVE: There is increasing evidence that the intestinal microflora plays an important role in the pathogenesis of inflammatory bowel disease. In the present study, we examined the role of the resident intestinal flora in our model of dextran sulfate sodium (DSS)-induced acute and chronic colitis in mice. METHODS: Acute colitis was induced in BALB/c mice with 5% DSS in their drinking water for 7 days. Chronic colitis was established after four cycles of feeding 5% DSS for 7 days and water for 10 days. For eliminating intestinal bacteria, mice were injected intraperitoneally with metronidazole and ciprofloxacin. We analysed four parameters: (1) body weight, (2) length of the colon, (3) histological score, and (4) myeloperoxidase activity. RESULTS: In acute DSS colitis treatment with antibiotics led to an improvement of the histological parameters (epithelial damage, P< 0.05; inflammatory infiltrate, P< 0.05) and colon length (P < 0.0028). A significant reduction in granulocyte infiltration was indicated by a 52.6% reduced myeloperoxidase activity in colonic biopsies. By contrast, in chronic colitis, treatment of mice with antibiotics failed to show significant effects. CONCLUSION: In acute DSS-induced colitis bacteria and/or bacterial products play a major role in initiation of inflammation but not in chronic DSS colitis.

Acute Disease↗
PubMed2000

Human intestinal epithelial cells secrete interleukin-1 receptor antagonist and interleukin-8 but not interleukin-1 or interleukin-6.

BACKGROUND: There is growing evidence that intestinal epithelial cells (IECs) are involved in the mucosal immune system. AIM: To assess the pattern of cytokines secreted by IECs and lamina propria mononuclear cells (LPMNCs). To achieve this, the expression and secretion of interleukin (IL)-1, IL-1 receptor antagonist (IL-1ra), IL-6, and IL-8 in human primary colonic and ileal IECs and LPMNCs from the same patient were studied. METHODS: IECs and LPMNCs were isolated from surgical specimens or endoscopic biopsy samples. mRNA expression was investigated by northern blot analysis. Secretion of IL-1beta, IL-6, IL-8, and IL-1ra was measured by enzyme linked immunosorbent assay. RESULTS: IL-1ra mRNA levels were higher in IECs than in LPMNCs in all probands. IL-8 mRNA was only present in low amounts in the IECs from two controls. In none of the specimens were IL-1beta and IL-6 mRNA present in IECs. Transcripts encoding IL-1beta, IL-1ra, IL-6, and IL-8 were identified in LPMNC preparations of all specimens. IECs from normal mucosa produced no detectable amounts of IL-1beta or IL-6, whereas LPMNCs did. IECs secreted some IL-8 (65 (9) pg/10(5) cells) but significantly more was generated by LPMNCs (408 (43) pg/10(5) cells, p<0.0001). However, IECs secreted more IL-1ra than did LPMNCs (120 (12) v 94 (11) pg/10(5) cells). In acute inflammation, IEC IL-1ra secretion was significantly increased. A correlation between secreted IL-1ra and the macroscopical degree of inflammation was found in Crohn's disease (r = 0.64, p<0.0001, n = 36) and ulcerative colitis (r = 0. 76, p<0.0001, n = 24). CONCLUSIONS: IECs from normal mucosa express and secrete IL-1ra and low amounts of IL-8, but no IL-1 or IL-6. In inflamed mucosa the secretion of IL-1ra by IECs is slightly increased but may be not sufficient to antagonise the greatly increased production of proinflammatory cytokines by LPMNCs and the IECs themselves.

Epithelial Cells↗
PubMed2000

Intracellular transport of high-density lipoprotein 3 in intestinal epithelial cells (Caco-2) is tubulin associated.

BACKGROUND: A retroendocytotic pathway for high-density lipoprotein 3 (HDL(3)) in cultured intestinal epithelial cell lines has been described. In small intestinal crypt cells and Caco-2, HDL(3) is internalized, transported to lipid droplets and, after solubilization of these lipid droplets, resecreted. In the present study we examined the mechanisms of intracellular transport of HDL(3) in the Caco-2 cell line. METHODS: Apolipoprotein E free HDL(3 )was gold-labeled for transmission electron microscopy and 1, 1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine iodide [DiI(3)] labeled for fluorescence and confocal laser scanning microscopy. For tubulin desintegration Caco-2 cells were incubated with taxol, colchicine and beta- and gamma-lumicolchicine. Tubulin staining was performed using a FITC labeled antibody. Uptake of HDL(3) was quantified by FACS analysis. RESULTS: HDL(3) was rapidly internalized and found to be in contact with lipid droplets in the perinuclear region after 10 min. By transmission electron microscopy a frequent colocalization of HDL(3)-containing vesicles and tubular structures was demonstrated. The close association of HDL(3)-containing vesicles with fluorescence stained tubulin could be confirmed by confocal laser scanning microscopy. Preincubation of the cells with taxol and colchicine did not completely prevent internalization but reduced it during a 2-hour incubation period to less than 50% of the control cells. The transport of DiI(3)-labeled HDL(3) to the lipid droplets in the perinuclear region was almost completely blocked by taxol and colchicine. CONCLUSION: Internalization and intracellular transport of HDL(3) in intestinal epithelial cells (Caco-2) is dependent on a tubulin-mediated mechanism.

Biological Transport↗
PubMed2000

Blood pressure-independent effects in rats with human renin and angiotensinogen genes.

The blood pressure-independent effects of angiotensin II (Ang II) were examined in double transgenic rats (dTGR) harboring human renin and human angiotensinogen genes, in which the end-organ damage is due to the human components of the renin angiotensin system. Triple-drug therapy (hydralazine 80 mg/L, reserpine 5 mg/L, and hydrochlorothiazide 25 mg/L in drinking water) was started immediately after weaning. Triple-drug therapy normalized blood pressure and coronary resistance, only partially prevented cardiac hypertrophy, and had no effect on ratio of renal weight to body weight. Although triple-drug therapy delayed the onset of renal damage, severe albuminuria nevertheless occurred. Semiquantitative scoring of ED-1-positive and MIB-5-positive (nuclear cell proliferation-associated antigen Ki-67) cells showed profound perivascular monocyte/macrophage infiltration and cell proliferation in kidneys and hearts of untreated dTGR. Triple-drug therapy had only a minimal effect on local inflammatory response or vascular cell proliferation. In contrast, a novel orally active human renin inhibitor (HRI), 30 mg/kg by gavage for 4 weeks, normalized blood pressure and coronary resistance and also prevented cardiac hypertrophy and albuminuria. ED-1-positive cells and MIB-5-positive cells were decreased by HRI in hearts and kidneys almost to levels observed in normotensive Sprague-Dawley rats. The renoprotective effects of HRI were at least in part due to improved renal hemodynamics and distal tubular function, since HRI shifted renal pressure-diuresis/natriuresis curves leftward by approximately 35 mm Hg, increased glomerular filtration rate and renal blood flow, and shifted the fractional water and sodium excretion curves leftward. In untreated dTGR, plasma Ang II was increased by 400% and renal Ang II level was increased by 300% compared with Sprague-Dawley rats. HRI decreased plasma human renin activity by 95% and normalized Ang II levels in both plasma and kidney compared with triple-drug therapy. Our findings indicate that in dTGR harboring human renin and angiotensinogen genes, Ang II causes end-organ damage and promotes inflammatory response and cellular growth largely independent of blood pressure.

Albuminuria↗
PubMed2000

Cytochrome P450-dependent renal arachidonic acid metabolism in desoxycorticosterone acetate-salt hypertensive mice.

Cytochrome P450 (P450)-dependent arachidonic acid metabolites may act as mediators in the regulation of vascular tone and renal function. We studied arachidonic acid hydroxylase activities in renal microsomes from normotensive NMRI mice, desoxycorticosterone acetate (DOCA)-salt hypertensive mice, and DOCA-salt mice treated with either lovastatin or bezafibrate, both of which improve hemodynamics in this model. Control renal microsomes had arachidonic acid hydroxylase activities of 175+/-12 pmol. min(-1). mg(-1). The metabolites formed were 20- and 19-hydroxyarachidonic acid, representing approximately 80% and approximately 20% of the total hydroxylation. Treatment with DOCA-salt resulted in significantly decreased hydroxylase activities (to 84+/-4 pmol. min(-1). mg(-1)) of the total microsomal P450 content and a decrease in immunodetectable Cyp4a proteins. Lovastatin had no effect on these variables, whereas bezafibrate increased arachidonic acid hydroxylase activities to 163+/-12 pmol. min(-1). mg(-1). In situ hybridization with probes for Cyp4a-10, 12, and 14 revealed that Cyp4a-14 was the P450 isoform most strongly induced by bezafibrate. The expression was concentrated in the cortical medullary junction and was localized predominantly in the proximal tubules. In conclusion, these results suggest that the capacity to produce 20-hydroxyarachidonic acid is impaired in the kidneys of DOCA-salt hypertensive mice. Furthermore, bezafibrate may ameliorate hemodynamics in this model by restoring P450-dependent arachidonic acid hydroxylase activities. Lovastatin, on the other hand, exerts its effects via P450-independent mechanisms.

Animals↗