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J E Ochoa

Publications and source records attributed to J E Ochoa.

9 recordsLinked to original sources
PubMed2000

[Epidemiology of leptospirosis in a livestock production area of the Andes].

A cross-sectional study was conducted to estimate the prevalence of Leptospira infection in populations of workers, cattle, and pigs in livestock operations and to explore some environmental and production system variables associated with seropositivity. The research was done between November 1997 and February 1998 in the municipality of Don Matías, in the northern part of the department of Antioquia, Colombia. The area has a cold climate, and there is a "pigs-grasses-milk" production system that utilizes pig dung to fertilize grazing pastures. A total of 23 farms were studied, and blood samples were obtained from 67 dairy and pig-raising workers, 174 dairy cows, 68 pigs for fattening, and 214 pigs for breeding. The microagglutination test (MAT) was used for six Leptospira serotypes. The seropositivity prevalence was 22.4% among the workers (95% confidence interval: 13.1% to 34.2%), 60.9% among the dairy cows (95% CI: 53.2% to 68.2%), 10.3% in the fattening pigs, and 25.7% in the breeding pigs. Four logistic regression models were constructed to identify the variables that predicted infection in the workers and in the dairy cows. A high prevalence of infection with Leptospira (serotypes pomona, bratislava, and hardjo) was found in this production system, where conditions are favorable for transmitting this microorganism to the different animal species and to humans.

Adult↗
PubMed1999

Effect of early stage of experimental diabetes on vascular functions in isolated perfused kidneys.

The present study investigates the renal vascular responsiveness to vasoactive agents in diabetic rats which present an early stage of renal failure. Adult male Wistar rats were administered alloxan (150 mg kg(-1), s.c.). Seven days later the right kidneys were isolated and perfused. Renal perfusion pressure was measured continuously. Concentration-response curves were plotted for noradrenaline (NA), sodium nitroprusside (SNP) and carbachol. In basal conditions, kidneys from diabetic rats presented a decreased vascular resistance compared with those from control rats. The vasoconstrictor response to NA showed decreased EC50 values in preparations from diabetic rats compared with control ones (EC50 nmols, control: 2.03 +/- 0.44, n = 8; diabetic: 0.84+/-0.18, n = 6, P < 0.05). This enhanced sensitivity to NA could be in line with the decreased glomerular filtration rate and cortical renal plasma flow previously described in vivo in our laboratory (Garcia, Girardi, Ochoa, Torres & Elias, 1998). Vasoconstrictor responses to phenylephrine were not however, different between diabetic and control rat kidneys. This suggests that the increased sensitivity to NA was due to impaired neuronal uptake since phenylephrine is not a substrate for neuronal uptake. After precontraction with phenylephrine, both endothelium-dependent (carbachol) and endothelium independent (SNP) vasodilator agents caused similar response in the preparations taken from the two groups of animals. So, the enhanced sensitivity to NA is not associated with a deficient dilator responsiveness of the renal vasculature. The vasodilator response to carbachol was the same in absence or presence of L-arginine in the perfusate, suggesting no alteration in its availability at this stage of diabetes. Diabetic animals showed increased plasma level of fructosamine and glycosylated haemoglobin (Hb A1c), indicating the presence of early glycated products at this stage of diabetes, which could be involved in a possible structural alteration of the vessels.

Animals↗
PubMed1998

Early manifestations of nephropathy in alloxan-treated rats.

An early stage of diabetic nephropathy was studied. Rat renal function was evaluated by clearance techniques, 7 or 15 days after alloxan administration (groups A7 and A15). Significant diminutions of glomerular filtration rate (inulin clearance) and p-aminohippurate clearance were observed in alloxan-treated rats. Diabetic animals presented glucosuria and enhanced water excretion. A natriuretic response was only observed in A15-rats. Arterial pressure increased along time, and enlarged lipid deposits in glomeruli and vessels of A7-kidney sections were observed. Thus, a vascular compromise at this time was suggested. To better characterize the set up of the renal dysfunction, other studies were performed in A7-group. Urinary protein excretion remained unchanged while a higher level of glycosylation of urinary proteins was observed in A7-rats. Histological studies revealed a normal general morphology in kidneys from diabetic rats. Immunohistochemical analysis in renal sections showed enlarged deposits of fibronectin in glomeruli and interstitium of alloxan-treated rats. Higher myeloperoxidase activity was observed in renal cortex from diabetic animals indicating leukocytes infiltration. These results indicated that 7 days after hyperglycemia induction, the animals presented a renal dysfunction characterized by hemodynamic alterations associated with vascular and glomerular structural impairments, without modifications in tubular function. The higher level of protein glycosylation and the inflammatory process at this early stage could be responsible for the beginning of diabetic nephropathy.

Animals↗
PubMed1996

Influence of trifluoperazine and verapamil on the isolated perfused rat kidney.

1. Isolated rat filtering kidneys were perfused with Ringer bicarbonate solutions containing either trifluoperazine (TFP, 50 microM) or verapamil (VER, 100 microM) to prevent tissue dysfunctions observed during perfusion. 2. Water, sodium and chloride kidney contents diminished under both treatments as compared with control preparations, and potassium content increased. 3. When albumin concentration was increased (10 g%) in the perfusion medium (nonfiltering kidney preparation) these effects of TFP or VER were not observed. 4. Lipid peroxidation and LDH release diminished significantly under 50 microM TFP but only slightly under 100 microM VER.

Animals↗
PubMed1995

Vascular and tubular actions of diazepam in isolated and perfused rat kidney.

The effects of diazepam were studied in the isolated rat kidney under conditions of constant flow. Kidneys were perfused with modified Ringer-Krebs solution. Diazepam produced a raised fractional excretion of water and sodium without hemodynamic changes, suggesting a direct effect on tubular transport mechanisms. Diazepam decreased renal perfusion pressure in a concentration-dependent fashion when kidneys were pretreated with either noradrenaline or potassium chloride. Similar responses were observed when 7-chloro-5-[4-chloro-phenyl]-1, 3-dihydro-1-methyl-2H-1,4-benzodiazepin-2-one (Ro 5-4864) or clonazepam was used. These data provide evidence for a relaxant effect of benzodiazepines on preconstricted renal vasculature.

Animals↗
PubMed1991

Role of lipid peroxidation on renal dysfunction associated with glutathione depletion. Effects of vitamin E.

This study was designed to investigate the role of lipid peroxidation in the pathogenesis of renal dysfunction in glutathione (GSH)-depleted rats. Renal function parameters and acid-base status were analyzed in diethylmaleate (DEM)-treated rats previously injected with vitamin E (Vit.E). Vit.E was effective in inhibiting the elevation in renal lipid peroxidation found in GSH-depleted rats. Vit.E also ameliorated the renal response to the metabolic acidosis without modification in lactate production induced by DEM administration. The increase in sodium and water urine excretion and the diminution of the urine to plasma osmolalities ratio were not reversed in these animals. These results lead us to conclude that lipid peroxidation is associated with distal acidification impairment observed with GSH-depletion, but it is not related to the sodium reabsorption alteration in the ascending loop of Henle.

Acid-Base Equilibrium↗
PubMed1987

Renal handling of bilirubin photoderivatives.

The renal handling of unconjugated bilirubin in the dark and during light exposure was analyzed using an isolated rat kidney preparation. The parameters tested were pigment disappearance from the perfusion medium, pigment uptake by tissue, and its renal clearance. The results indicated that despite the fact that pigment disappearance from the medium was similar for both forms of pigment, the extraction ratio was higher for irradiated pigment than for pigment in the dark. When renal clearance of pigment was plotted vs pigment uptake of tissue, the results indicated that irradiated pigment may be more efficiently removed by the kidney. In addition, data on the rate of secretion of p-aminohippurate suggested that both pigment forms shared a common site for secretion.

Animals↗
PubMed1986

Rat kidney function related to tissue glutathione levels.

Rat renal function was evaluated during acute depletion of glutathione (GSH) produced by different doses of diethyl-maleate (DEM). Significant alterations in renal function were observed when the GSH level diminished. The replenishment of GSH and the restoration of renal function were also investigated at various times after the injection. Similar time courses were observed of both the GSH level and renal functions, but the former was shortest. This suggests that the restoration to normal of GSH renal content was necessary in order to regain appropriate kidney function. Furthermore, the fact that impairment of sodium excretion occurred simultaneously with GSH depletion may be considered as evidence of the first event in GSH protective action. It may be hypothetized that the thick ascending limb is the principal renal target for this deficiency.

Animals↗