Endothelins and markers of renal damage in recently diagnosed hypertensive patients

Endothelin has been identified as a potent vasoconstrictor. The aim of this study was to evaluate urinary endothelins and their relation to other markers of renal damage, such as microalbuminuria, creatinine, and N-acetyl-beta-glucosaminidase (NAG), in a group of recently diagnosed (less than 1 year) hypertensive subjects and a control group. We selected 50 subjects and divided them into two groups: 27 hypertensive patients (15 females and 12 males) without previous pharmacologic therapy, and 23 healthy, normotensive subjects (12 females and 11 males). All patients underwent a history and physical examination, chest x-ray, electrocardiography, funduscopy, and hematologic and biochemical analyses. Endothelins, microalbuminuria, creatinine, and NAG values were also determined in 24-hour urine samples. Creatinine, microalbuminuria, and NAG values were found to be higher in hypertensive than in normotensive subjects. The hypertensive group showed a nonsignificant elevation of total endothelin. In conclusion, the determination of elevated urinary endothelin does not appear to be an early marker of organ damage in hypertensive subjects. The urinary excretion of protein, creatinine, and NAG was higher in hypertensive subjects. A positive correlation was found between the urinary excretion of endothelins and markers of renal damage, microalbuminuria and NAG values. The relationship between endothelins and hypertension was without statistical significance.     

Protective role of melatonin and retinol palmitate in oxidative stress and hyperlipidemic nephropathy induced by adriamycin in rats

Abstract: We have studied the effects of melatonin and retinol palmitate (RP) on the nephropathy and oxidative stress induced by a single and high dose of adriamycin (AD) in Wistar male rats. A dose of melatonin (75 μg/ kg/day) and a dose of RP (0.25 g oily solution/kg/day, sc) were injected 3 and 9 days before and after the administration of AD (25 mg/kg, i.p.), respectively. After the decapitation, samples were taken from the neck vascular trunk in order to determine the triglycerides, total cholesterol, phospholipids, HDL-cholesterol, total proteins, urea, lipoperoxides, and reduced glutathione (GSH). We estimated the lipoperoxide and glutathione (GSH) contents in renal homogenates, and the excretion of proteins in urine over a 24 hr period. The administration of AD caused significant increases in proteinuria and in the other parameters studied [lipids (triglycerides, total cholesterol, phospholipids, and HDL-cholesterol), nonprotein nitrogen compounds, and lipoperoxides]. AD increased the lipoperoxide content, but it decreased the GSH content in the kidney. Both melatonin and RP, although melatonin more significantly, decreased the intensity of the changes produced by the administration of AD alone. In fact, melatonin was quite efficient in reducing the formation of lipoperoxides, restoring renal GSH content and decreasing remarkably the severity of proteinuria. These results support the powerful antioxidant action of melatonin at renal level and a lower antioxidant action of retinol. Likewise, these data reinforce the hypothesis which supports the pathogenetic role and the close relation between the oxidative stress and the expression of the nephropathy induced by AD. However, in spite of this obvious antioxidant effect of melatonin in the kidney, additional studies are required to establish accurately the role of this pineal indole in the regulation and dynamics of the antioxidative defense enzyme system, which neutralizes the damaging effect of free radicals, both endogenous and exogenous, in this organ.     

Identification of the receptor for erythropoietin by cross-linking to Friend virus-infected erythroid cells.

Erythropoietin (Epo) is a glycoprotein hormone that regulates erythroid development and interacts with surface receptors on developing erythroid cells. In this laboratory, a cell system with a relatively pure population of erythroid cells that respond to Epo has been developed. Immature erythroid cells are obtained from the spleens of mice infected with the anemia strain of Friend virus. The binding of 125I-labeled Epo (125I-Epo) to plasma membranes from these cells was studied in this investigation. 125I-Epo binding reached equilibrium within 20 min at 37 degrees C. Twenty percent of the receptors bound 125I-Epo with a Kd of 0.08 X 10(-9) M, while the remaining receptors bound the hormone with a Kd of 0.6 X 10(-9) M. In this study, a receptor for Epo was identified by cross-linking 125I-Epo to the receptor in intact cells and plasma membrane preparations using disuccinimidyl suberate. Polyacrylamide gel electrophoresis revealed two labeled bands of 100 and 85 kDa. The 85-kDa band was more heavily labeled (65%) than the 100-kDa band. Both bands were equally decreased when increasing amounts of unlabeled Epo were included in the binding mixture, indicating a specific interaction of 125I-Epo with the receptor.     

Symptomatic gastrointestinal amyloidosis in an HIV-infected patient

We report a rare case of symptomatic GI amyloidosis in an HIV-infected patient who ultimately developed uncontrollable upper GI bleeding. Gastric and jejunal biopsies revealed amyloidosis. Although the patient's history suggested the possibility of secondary amyloidosis, immunohistochemical staining together with serum electrophoresis and immunofixation revealed the presence of lambda light chains indicating primary amyloidosis.     

A bio-psycho-social approach to acute hypertensive disease in pregnancy

In this paper, the approach to the genesis of the acute hypertension of pregnancy, uses a conceptual and methodological perspective adjusted to its multifactorial nature; a set of questions with epidemiologic focus is proposed, in order to vinculate psychosocial factors with the biologic processes characteristic of this health problem.     

Necrotizing colitis in patients with cancer.

Necrotizing lesions of the colon occur in patients with malignancy. We identified 26 patients with cancer (23 with acute leukemia and three with solid tumors) who died from necrotizing colitis. Autopsies revealed three pathologic categories: pseudomembranous colitis in 69 per cent, agranulocytic colitis in 19 per cent and ischemic colitis in 12 per cent. Most died from sepsis. A comparison of characteristics was made with a control population matched for diagnosis, age, cause of death and duration of neoplasia. Nearly all patients in both groups had fever and were granulocytopenic secondary to chemotherapy. Most received antineoplastic and antimicrobial regimens during the month prior to their terminal illness. Abdominal pain and distention, stomatitis and necrotizing pharyngitis were frequently associated with colitis. Hyperbilirubinemia was a frequent late complication in those with colitis and the control group. Single and multiorganism septicemia were found more frequently in patients with colitis. As antemortem diagnosis was unusual, aggressive attempts at diagnosis are necessary to assess the true incidence of this disorder and the best therapy.