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Biomedical subjects

J S Horvath

Publications and source records attributed to J S Horvath.

At least 19 recordsLinked to original sources
PubMed2003

Placental tissue interleukin-10 receptor distribution in pre-eclampsia.

PROBLEM: Reduced placental (trophoblast) cytokine interleukin-10 (IL-10) occurs in human pre-eclampsia. Along with an increase in inflammatory cytokines this may play an important role in the development of hypertension in pregnancy. It is not clear whether the changes in placental IL-10 are due to a change in the placental cell production of IL-10 or a result of changes in cytokine receptor status in adjacent tissues. This study is aimed at qualifying the presence and distribution of IL-10 receptors in women with a pre-eclamptic outcome compared to normal pregnancy and gestational hypertension. METHOD OF STUDY: Patients at the KGV Hospital, Sydney was selected for the study. Placentas were collected fresh and paraffin serial sections made. Sections were stained with IL-10 receptor antibody (10 microgram/mL) using avidin-biotin immunohistochemistry. Tissues of patients with pre-eclampsia (n=11) were compared with normal pregnancy (n=12). Pre-eclampsia was defined as a blood pressure >140/90 mmHg on two occasions and de nova proteinuria >300 mg per day which resolved post-partum. The fetal weights, gestational ages and maternal ages at delivery were compared (ANOVA) and the differences in staining of decidual and villous tissues were graded according to density. Statistical comparisons were made using the Kruskal-Wallis test. RESULTS: The groups were similar for maternal gestational age but delivered at earlier gestation and with lower fetal weight. There was significantly less villous cytotrophoblast staining for IL-10 receptor in all groups (P=0.012) compared to decidual trophoblast cells. There was equal intensity and density of extravillous straining observed in normal pregnancy (45 +/- 12%) positive cells compared to pre-eclampsia (27 +/- 12%). CONCLUSION: IL-10 receptors are present in greater concentration in the extravillous (decidual) trophoblast compared to villi. The decrease in IL-10 produced by trophoblast cells in pre-eclampsia is not explained by a difference in the IL-10 receptor distribution compared to normal pregnancy.

Female↗
PubMed2002

Transforming growth factor-beta 1 does not relate to hypertension in pre-eclampsia.

1. Pre-eclampsia is a human disease of pregnancy characterized by high blood pressure, proteinuria and end-organ damage, if severe. Pre-eclampsia is thought to be related to changes in early placental development, with the formation of a shallower than normal placental bed. 2. Transforming growth factor (TGF)-beta1 is a multifunctional fibrogenic growth factor involved in immune regulation that is elevated in some populations with a high risk of hypertensive end-organ disease related to increases in endothelin release. Transforming growth factor-beta1 is also an important factor in placental implantation. Alterations in TGF-beta1 may be related to abnormal placental development in early pregnancy and, thus, are a candidate for the development of hypertension in pre-eclampsia. 3. The aim of the present study was to examine the placental distribution and serum concentration of TGF-beta1 in patients with pre-eclampsia compared with normal pregnancy. 4. Patients with pre-eclampsia (n = 12) were compared with patients with normal pregnancy (n = 14). Transforming growth factor-beta1 was determined by TGF-beta1 Max ELISA (Promega, Madsion, WI, USA) after serum dilution (1/150) and acid activation. Placental distribution was determined by immunostaining with TGF-beta1 (Santa Cruz, Santa Cruz, CA, USA; 20 ng/mL) and the villi and decidual trophoblast were scored for intensity and extent of staining. 5. Patients with pre-eclampsia had a mean gestational age of 36 weeks, whereas those with a normal pregnancy had a mean gestational age of 39.0 +/- 0.4 weeks. There was no difference in TGF-beta1 concentration between the two groups (mean (+/-SEM) 27.1 +/- 1.0 vs 26.4 +/- 0.7 pg/mL for normal pregnancy and pre-eclampsia, respectively; P = 0.73, Mann-Whitney U-test). There was no correlation between systolic or diastolic blood pressure and TGF-beta1 concentration (regression analysis P = 0.4 and 0.2). Immunostaining was absent in the villous trophoblast cells and endovascular and extravillous trophoblast of term placentas. 6. Although TGF-beta1 is present in trophoblast cells in early pregnancy during placental development, TGF-beta1 concentrations were not increased in the placenta at term in pre-eclampsia and there was no correlation between blood pressure and serum TGF-beta1, suggesting that TGF-beta1 does not play a role in the development of late gestation pre-eclampsia and hypertension.

Adult↗
PubMed2000

The effects of the menstrual cycle, pregnancy and early lactation on haematology and plasma biochemistry in the baboon (Papio hamadryas).

The changes in the haematology and clinical biochemistry associated with the different stages of the menstrual cycle, gestation and lactation in the baboon (Papio hamadryas) were evaluated in a prospective longitudinal study. Serial EDTA and heparin blood samples were collected from 12 baboons. Haemoglobin concentration, haematorcrit, red blood cell and white blood cell counts were decreased in the luteal compared to the follicular phase (P<0.001); the reverse effect was observed for platelet count, total protein and albumin concentrations. The changes in plasma concentrations of sodium, potassium, urea, creatinine and cholesterol and plasma osmolality were characterized by reductions (P<0.01) in early pregnancy which were maintained throughout gestation. Plasma concentrations of total protein, albumin and alkaline phosphatase, as well as haemoglobin, haematocrit and red cell count were reduced (P<0.001) from mid-gestation. Platelet count and plasma calcium concentration fell continuously throughout gestation (P<0.001). Plasma triglycerides were lower and plasma iron was higher (P<0.01) in gestation compared to the phases of the menstrual cycle and lactation. By 1 week post partum, all parameters except haemaglobin had returned to pre-conception levels.

Animals↗
PubMed1999

End-stage renal disease in aboriginals in New South Wales: a very different picture to the Northern Territory.

OBJECTIVES: To compare the incidence of end-stage renal disease (ESRD) among Aboriginals in New South Wales with the incidence among Aboriginals in the Northern Territory, and to compare the patterns of ESRD among Aboriginals and non-Aboriginals in NSW. DESIGN: Secondary data analysis of information from unpublished and published Australia and New Zealand Dialysis and Transplant Registry reports. MAIN OUTCOME MEASURES: Average annual incidence of ESRD (persons per million); form of renal replacement therapy; mortality at 31 March 1998; patient and graft survival one and five years after transplant. RESULTS: Each year in NSW, 5-17 new Aboriginal patients are treated for ESRD. There was no increase in the average annual incidence of ESRD among NSW Aboriginals (118 per million in 1988-1989 and 111 per million in 1996-1997), whereas incidence in the NT increased from 255 per million to 800 per million. In NSW, ESRD was attributed to diabetes in 32% of Aboriginal patients, compared with 13% of non-Aboriginal patients (P < 0.001). In NSW, Aboriginal patients were younger and more likely to be female, a pattern similar to that in the NT. The outcome of ESRD treatment is not significantly different between Aboriginals and non-Aboriginals in NSW. CONCLUSION: There is a different pattern of incidence of ESRD and of outcomes with treatment among Aboriginals in NSW compared with those in the NT. A possible explanation is that the lower incidence in NSW reflects less profound socioeconomic disadvantage and better access to primary and specialist care.

Adolescent↗
PubMed1999

Low-dose nitro-L-arginine administration in baboon (Papio hamadryas) pregnancy.

1. The purpose of the present study was to examine the effect of nitric oxide (NO) inhibition on mean arterial pressure (MAP), endothelin (ET) and the renin-aldosterone system in pregnancy in the non-human primate (baboon). 2. Twenty pregnant baboons (Papio hamadryas) were examined prospectively after the administration of an oral NO inhibitor in different phases of pregnancy. Haemodynamic responses to NO inhibition, evidence of pre-eclampsia and the renin-aldosterone system were examined under anaesthesia. 3. Oral NL-nitro-L-arginine (NOLA; 5 or 10 mg/kg) was given for 1 week in early (6-8 weeks gestation), middle (14-16 weeks gestation) and late (22-24 weeks gestation) pregnancy and while non-pregnant. Mean arterial pressure, heart rate, haematology, biochemistry, ET, plasma renin activity (PRA) and aldosterone were measured. Foetal effects of NOLA were also examined by ultrasound and neonatal measurements. 4. Nitric oxide inhibition led to an increase in MAP in non-pregnant animals (9 mmHg) and in middle and later pregnancy (6 and 7 mmHg, respectively). Mean arterial pressure in early pregnancy was not affected. A reduction in PRA occurred after NO inhibition in all stages of pregnancy. Significant proteinuria occurred only in late pregnancy. 5. Nitric oxide is involved in the maintenance of lower blood pressure in late pregnancy and inhibition leads to an increase in blood pressure and proteinuria in the baboon. Nitric oxide insufficiency may contribute to the clinical manifestations of human pre-eclampsia. Nitric oxide was not involved in the normal vasodilation of early primate pregnancy.

Aldosterone↗
PubMed1999

Biochemistry and haematology values for the baboon (Papio hamadryas): the effects of sex, growth, development and age.

A retrospective study evaluated the influence of sex and age on plasma biochemistry and haematology parameters in a captive-bred colony of baboons. Over 1,140 ETDA and heparin blood samples were obtained from 160 clinically normal baboons between the ages of 11 months and 11 years. Data for these blood tests were analysed for the effects of sex, age and sex age interactions. Sex, age and sex age interactions were detected for many plasma biochemistry and haematological parameters. The reference range values for platelets, white-blood cells and mean corpuscular volume and plasma chloride, glucose, total protein and iron were higher (P < 0.01) and red blood cell, plasma sodium, potassium, total CO2, creatinine, urea, total bilirubin, albumin, alkaline phosphate, gamma glutamyl transpeptidase and phosphate were lower (P < 0.01) in the female compared to the male population. Sex age interactions (P < 0.05) were seen with haemoglobin, white blood cells, haematocrit, mean corpuscular volume, sodium, creatinine, urea, calcium, phosphate, total bilirubin, total protein alkaline phosphatase, the liver enzymes and triglycerides. Plasma alkaline phosphatase was highest ( > 800 micro/l) in young juveniles of both sexes; creatinine was higher in older ( > 4 years) compared to younger baboons of the same sex (P < 0.05). Plasma cholesterol and triglycerides were greater (P < 0.01) in young baboons compared to older animals.

Age Factors↗
PubMed1996

A unique design for ease of access and movement of captive Papio hamadryas.

Baboons are widely used in biomedical research but their size and behaviour present potential problems with accessibility. A unique system has been developed that ensures ease of access to all animals in a colony of Papio hamadryas. Two distinct caging complexes were linked by a network of overhead races, that are connected to a physical restraint area where individual animals could be separated, restrained and weighed without being handled. Access to and separation of individual family groups was achieved in this manner. This race system proved to be time effective, simple, sturdy, safe and hygienic.

Animals↗
PubMed1995

Maternal and neonatal outcome of patients classified according to the Australasian Society for the Study of Hypertension in Pregnancy Consensus Statement.

OBJECTIVE: To outline the maternal and perinatal features and outcome of patients referred to a tertiary referral obstetric hospital for management of their hypertension. SETTING AND PATIENTS: 205 consecutive public patients admitted for assessment of hypertension (either full admission or day-stay) to King George V Hospital's Hypertension in Pregnancy Unit, between February 1993 and January 1994. DESIGN: A prospective study in which patients were classified according to the Australasian Society for the Study of Hypertension in Pregnancy (ASSHP) Consensus Statement classification. RESULTS: Of the 205 patients, 25% did not meet the criteria for pre-eclampsia or chronic hypertension, 33% had mild pre-eclampsia, 34% had severe pre-eclampsia and the remainder had chronic hypertension. The mean gestation at delivery for those with mild pre-eclampsia was 38.3 weeks and for severe pre-eclampsia 35.3 weeks. For the mild and severe groups respectively, the rate of elective delivery for raised blood pressure was 56% and 53%; for caesarean section, 17% and 61%; and for perinatal death, 2% and 4%. In the severe group, 49% had fetal problems and 25% required intravenous antihypertensives. CONCLUSIONS: The multisystem nature of pre-eclampsia makes comparison of management protocols difficult. Ongoing audit is needed of maternal and perinatal outcomes and features of disease in patients with hypertension in pregnancy under a universal classification. The ASSHP classification system successfully identifies patients who require more intensive management and intervention.

Chronic Disease↗
PubMed1994

Fetotoxicity of angiotensin-converting enzyme inhibition in primate pregnancy: a prospective, placebo-controlled study in baboons (Papio hamadryas).

OBJECTIVES: Serious concerns have been raised about angiotensin-converting enzyme inhibition in pregnancy. The central question remains: does toxicity of angiotensin-converting enzyme inhibition pertain to pregnant humans? STUDY DESIGN: A prospective, placebo-controlled study was performed to investigate the effect of angiotensin-converting enzyme inhibition on pregnancy outcome in the baboon. Subjects (N = 12) received active and placebo treatments sequentially in a crossover protocol. Data were analyzed with two-sample t tests, analysis of variance, Fisher's exact test, or Kaplan-Meier survival analysis, where appropriate. RESULTS: Chronic administration of enalapril (7.5 mg per day) from before conception achieved moderate but sustained angiotensin-converting enzyme inhibition as determined by repeated measures of renin-angiotensin system parameters (serum angiotensin-converting enzyme activity, plasma renin activity and plasma angiotensin I, angiotensin II, and aldosterone concentrations). Serum angiotensin-converting enzyme activity was significantly reduced throughout (< 10 nmol.ml-1.min-1, p < 0.01), with significant increases in plasma renin activity and angiotensin I (p < 0.01). Angiotensin II and aldosterone were maintained unchanged compared with placebo. There was a significant incidence of fetal death or intrauterine growth retardation in fetuses exposed to enalapril (eight of 13, zero on placebo, p < 0.01). When the definition of adverse pregnancy outcome was restricted to fetal death alone (four of 13) the difference remained significant (p < 0.05). Maternal arterial pressure was unchanged before conception, but a small and significant fall (10 to 15 mm Hg, p < 0.01) was detected throughout pregnancy. There was no fetal malformations. CONCLUSION: The study provides definitive evidence for serious consequences of angiotensin-converting enzyme inhibition in pregnancy of high-order primates.

Aldosterone↗
PubMed1994

Haemodynamic actions of a nitric oxide (EDRF) synthesis inhibitor in conscious baboons (Papio hamadryas).

1. The haemodynamic effects of intravenous nitric oxide inhibitor, N-nitro-L-arginine (NOLA), were examined in four conscious non-restrained baboons (Papio hamadryas). Mean arterial pressure, (MAP), systemic vascular resistance (SVR) and cardiac output (CO) were measured at timed intervals up to 24 h after a bolus injection of NOLA. 2. N-nitro-L-arginine increased blood pressure in a dose-dependent manner up to 9.5 mg/kg. Increases in blood pressure were accompanied by increases in SVR and decreases in CO, with a significant fall in heart rate. 3. One animal received 9.5 mg/kg NOLA and became unconscious, suggesting cerebral vasospasm. 4. Vascular effects of nitric oxide contribute significantly to the regulation of arterial blood pressure under physiological conditions in the baboon.

Amino Acid Oxidoreductases↗
PubMed1994

Helminthic infestation complicated by intussusception in baboons (Papio hamadryas).

Two juvenile baboons presented with diarrhoea, which did not resolve completely following antibiotic therapy. Ileal intussusception was identified at autopsy in both cases. Trichuris was the only gastrointestinal pathogen for which evidence could be found. This helminth is well-recognized as a cause of intussusception in human infants, but the complication has not been reported previously in non-human primates. It is likely to be fatal if undiagnosed.

Animals↗
PubMed1992

Inhibition of fibroblast proliferation in L-valine reduced selective media.

A selective cell culture medium, D-valine minimal essential medium (92 mg/l), has been developed to inhibit the proliferation of fibroblasts in cell culture (Gilbert & Migeon 1975). Substitution of D-valine for L-valine prevents fibroblast growth due to the absence of D-amino acid oxidase in these cells. Most cell cultures require foetal bovine serum as an essential component of the culture media, however foetal bovine serum contains L-valine, negating the value of D-valine selective media. To overcome this difficulty, we have produced a modified selective media for cell culture, by the dialysis of foetal bovine serum and confirmed its ability to inhibit fibroblast growth whilst still allowing the proliferation of epithelial cells in culture.

3T3 Cells↗
PubMed1991

Early blood pressure control improves pregnancy outcome in primigravid women with mild hypertension.

OBJECTIVE AND DESIGN: The aim of this study was to evaluate treatment of mild to moderate hypertension (less than 170/110 mmHg) in pregnancy in a prospective, randomised, double-blind trial. SETTING AND PATIENTS: Pregnancy outcome was studied for 52 primigravid women, managed in hospital from early in the third trimester. INTERVENTIONS: Patients were randomly allocated either to placebo or to active treatment (clonidine plus hydralazine). MAIN OUTCOME MEASURES AND RESULTS: Maternal deterioration dictated withdrawal from trial therapy for eight patients receiving placebo, but for only one receiving active treatment. Maternal proteinuria occurred only in the placebo group. Intention-to-treat analysis showed a significant increase in premature delivery for complications in the placebo group (P less than 0.05), despite active blood pressure treatment for those withdrawn from the group because of severe hypertension (170/110 mmHg or higher). Neonatal respiratory distress requiring intensive care occurred only in babies born to women in the placebo group. There were no perinatal deaths and no adverse effects of treatment in the neonates. CONCLUSIONS: The study indicates that early control of mild hypertension in pregnancy can prevent progression to emergency premature delivery.

Adult↗
PubMed1991

Cyclosporin A blood levels are not influenced by dietary alterations in lipids.

The bioavailability of an oral dose of cyclosporin A (CSA) is variable. CSA is highly lipid soluble with approximately 40% of the CSA in the intravascular compartment bound to lipoproteins. This study was undertaken to determine what effect acute alterations in plasma lipids following a high fat meal would have on CSA whole blood levels 12 to 14 hours after the last dose. Fifteen renal transplant patients with stable renal function and on CSA therapy alone for a minimum of three months were investigated. Anthropometric data was recorded and baseline blood samples were drawn for CSA, liver function, renal function, vitamins A and E. triglycerides, cholesterol and lipoproteins following an overnight fast. The subjects then received a high fat (72.8% of caloric value) or a low fat (12% of caloric value) meal and post-prandial samples were drawn at two and four hours. The correlation between CSA levels (r = 0.72) taken on the two study days (one week apart) was less than expected despite no change in dosage. Cholesterol levels remained unchanged but triglyceride levels rose following the high fat meal. CSA levels did not correlate with the post-prandial changes in triglycerides, nor with any other parameter of lipid metabolism, lipid transport, or total body fat. This study demonstrated that CSA whole blood levels are not influenced by acute variations in lipids following a meal and therefore the time of sampling for a CSA trough level will not be influenced by the proximity to a recent meal.

Adult↗
PubMed1990

Energy supplementation and the nutritional status of hemodialysis patients.

Twenty-one patients undergoing regular hemodialysis completed a trial of energy supplementation. Nine patients added the glucose polymer Polycose to their usual diet and 12 acted as control subjects. The supplemented patients were asked to incorporate 100 or 150 g polymer, equivalent to 1600 or 2400 kJ (400 or 600 kcal) into their usual diet, daily for 6 mo. This resulted in a mean increase in energy intake of 1630 kJ (p less than 0.05) and a mean weight gain of 3.1 kg (p less than 0.005). The addition of glucose polymer to the diet resulted in a mean increase in body fat of 1.8 kg and the lean body mass increased by 1.3 kg. No significant effect on plasma triglycerides, urea, or creatinine was detected. The intake of macro- and micronutrients was not adversely affected and no clinical or psychological side effects were reported. Follow-up of these patients showed that the weight gain was maintained after 6 mo. Glucose polymer was an effective energy supplement that had beneficial effects on the nutritional status of hemodialysis patients.

Adult↗
PubMed1990

Evidence that alterations in renal metabolism and lipid peroxidation may contribute to cyclosporine nephrotoxicity.

This study was designed to investigate aspects of renal xenobiotic metabolism and the renal cellular response to drug-induced injury, in mediating cyclosporine nephrotoxicity. The relation between CsA and renal enzyme activity has not previously been investigated. In this study, CsA induced alterations in rat renal cortical microsomal NADPH cytochrome P-450 reductase activity, microsomal and mitochondrial lipid peroxidation, and renal cortical glutathione levels were investigated. CsA, in vivo (50 mg/kg/day for 4 days), increased in vitro lipid peroxidation in microsomes and mitochondria. CsA produced a significant uncompetitive inhibition of renal NADPH cytochrome P-450 reductase activity. The low activity and maximal enzyme velocity (Vmax) suggest that the amount of renal enzyme available for metabolism may be a rate-limiting step and could contribute to the development of toxicity. CsA in vivo reduced the renal cortical glutathione ratio (GSH/GSSG), which may also reduce the renal cellular response to CsA injury. This study has demonstrated that CsA nephrotoxicity may, in part, be mediated by CsA-induced alterations in renal xenobiotic metabolism.

Animals↗
PubMed1990

Hemodynamics of conscious unrestrained baboons, including cardiac output.

A method is described for comprehensive hemodynamic study of undisturbed baboons (Papio hamadryas) that incorporates cardiac output measurement by thermodilution. Instrumentation includes arterial, aortic, and central venous catheterization by a surgical technique that does not require entry to peritoneal or thoracic cavities. It provides a means for right atrial indicator delivery with aortic temperature recording of thermodilution curves. Accuracy was confirmed by comparison to measurement by Swan-Ganz catheters. Diurnal variations of systemic arterial pressure in long-term study of conscious baboons were shown to result from significant increases in cardiac output by day (P less than 0.001), despite concomitant falls in systemic vascular resistance. The cardiac output values obtained were 0.13 l.min-1.kg-1 at night and 0.16 l.min-1.kg-1 by day. Comparison of these results to previous reports of cardiac output in baboons highlights the inadequacies of methods that require physical restraint or anesthesia. This technique also leaves the baboons intact for subsequent breeding or experimental use after catheter removal without the need for further surgery.

Animals↗