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Biomedical subjects

M E Miranda

Publications and source records attributed to M E Miranda.

At least 37 records · Page 2Linked to original sources
PubMed1994

Purine metabolism in women with primary gout.

PURPOSE: Uncontrolled studies have shown that women with gout have higher serum urate concentrations and similar or lower urinary uric acid excretion rates than do men with gout. These observations suggest a more defective tubular transport of uric acid in women than in men with gout. In this prospective study we assessed purine metabolism in women with primary gout under controlled conditions. We also examined whether there are sex-related differences in plasma and urinary purine concentrations among patients with primary gout. SUBJECTS AND METHODS: Ten women with crystal-proved primary gout and normal serum creatinine levels (below 116 mmol/L) were studied while they were on a purine-restricted diet and taking no medications known to influence uric acid metabolism. For comparison, 20 men with primary gout and 10 women without gout, matched for age, race, and body mass index, were studied under the same conditions. In each subject, plasma and 24-hour urinary uric acid, hypoxanthine, and xanthine concentrations were measured. The mean of three consecutive determinations for plasma purines and five for urinary purines was used. Standard formulas were used to calculate the renal clearances and the fractional excretion of purines. RESULTS: Mean plasma urate, hypoxanthine, and xanthine levels were significantly higher in women patients with primary gout compared with normal women (P < 0.05). Mean 24-hour urinary uric acid excretion was similar in both groups. Daily urinary hypoxanthine and xanthine excretion rates were significantly lower in gouty women patients than in control women (P < 0.05). The renal clearances and the fractional excretion of uric acid, hypoxanthine, and xanthine were markedly lower in women with primary gout than in control women (P < 0.05). Plasma and urinary purine concentrations were similarly increased and diminished, respectively, in women and men patients with primary gout. Plasma urate, hypoxanthine, and xanthine levels were inversely and significantly associated with the fractional excretion of uric acid (r = -0.520; P = 0.003), hypoxanthine (r = -0.555; P = 0.002), and xanthine (r = -0.384; P = 0.040), respectively. CONCLUSION: Women with primary gout have markedly diminished uric acid, hypoxanthine, and xanthine excretion rates. The disturbance of purine metabolism appears to be of a similar magnitude to that observed in gouty men. The absence of significant sex-related differences in plasma and urinary purine concentrations suggests a similar tubular dysfunction for purine excretion in women and men with primary gout.

Aged↗
PubMed1993

Hereditary nephropathy associated with hyperuricemia and gout.

BACKGROUND: The clinical characteristics of hereditary nephropathy associated with hyperuricemia or gout have not been fully described, and the pathogenetic role of increased serum urate concentration is controversial. METHODS: We examined the clinical characteristics of 14 patients and purine metabolism of seven patients, while they were on a purine-restricted diet, in two families with hereditary nephropathy associated with asymptomatic hyperuricemia or gout. Results of plasma and urinary purine measurements were compared with those obtained in 25 patients with gout and renal insufficiency and in 25 normal subjects. Eight subjects in both families were followed up for a mean of 44 months. Allopurinol was given to all patients and enalapril maleate to hypertensive subjects. RESULTS: All patients had some combination of hyperuricemia, gout, renal insufficiency, arterial hypertension, and reduced kidney size. Decreased glomerular filtration rate was proportional to the decreased renal plasma flow. Renal vascular resistance was markedly increased in the patients with diminished renal plasma flow. All patients with familial nephropathy showed diminished urinary uric acid, hypoxanthine, and xanthine excretion rates. Purine under-excretion was more severe in affected patients with familial nephropathy than in patients with gout and renal insufficiency. Kidney biopsy specimens from three patients with familial nephropathy showed tubulointerstitial lesions and ischemic changes in glomeruli but no uric acid crystals. The kidney uric acid content was normal. Allopurinol treatment normalized serum urate levels, but serum creatinine concentrations increased and creatinine clearance decreased in all patients with familial nephropathy. One patient with gout only at initial evaluation developed renal failure during the follow-up period. CONCLUSIONS: Increased serum urate concentrations in hereditary nephropathy associated with hyperuricemia and gout are due to severe impairment of uric acid excretion. Hyperuricemia does not appear, however, to be of pathogenetic relevance and may be a consequence of a primary disruption of renal hemodynamics.

Adolescent↗
PubMed1992

Surveillance in evacuation camps after the eruption of Mt. Pinatubo, Philippines.

To obtain accurate, timely data on the health status of persons in evacuation camps after the eruption of the Mt. Pinatubo volcano, the Philippine Department of Health (DOH) conducted a survey of the health needs of the evacuees and established disease surveillance in each camp. Surveys of the camps revealed that sources of potable water, sanitary means of waste disposal, and shelters were inadequate. Disease surveillance showed that measles, acute respiratory infections, and diarrhea were the most important problems. Surveillance detected outbreaks of measles and an outbreak of vomiting and diarrhea in the camps. Deaths, primarily caused by measles (31%), diarrhea (29%), and respiratory infections (22%), totaled 349 in the first 12 weeks. Death rates peaked in the seventh week, when a death rate of 26/10,000 occurred among the Aetas, a tribe evacuated from the slopes of the volcano. The surveys guided the DOH in allocating supplies and medicine, while disease surveillance enabled disaster managers to monitor the effectiveness of health programs, identify high-risk groups, and respond appropriately to the situation.

Diarrhea↗
PubMed1992

Intrafamilial outbreak of Mediterranean spotted fever.

The existence of intrafamilial outbreaks of spotted-fever group rickettsioses has seldom been reported, and their true incidence is not known. We here report the occurrence of Mediterranean spotted fever (MSF) in three members of a family: a boy, his grandmother and his grandfather. The infection resolved uneventfully in the boy, and followed a more protracted course in the two older patients, who suffered complications including drowsiness, clotting defects and acute renal failure. This finding highlights the importance of conditioning factors such as age and associated illnesses in the prognosis of infection due to Rickettsia conorii, and suggests that strict surveillance of individuals at risk of infection is necessary for prompt recognition of the onset of the illness and initiation of antibiotic treatment without delay.

Aged↗
PubMed1992

Outbreak of fatal illness among captive macaques in the Philippines caused by an Ebola-related filovirus.

Following the detection of an Ebola-like virus in cynomolgus macaques recently imported into the United States from The Philippines, studies were initiated to document transmission at export facilities located in the latter country. At one export facility, 52.8% of 161 monkeys that died over a 2.5-month period were shown to be infected with this virus using an enzyme-linked immunosorbent assay to detect antigen in liver homogenates. A case fatality rate of 82.4% was documented for the infected monkeys. The initial anti-viral antibody prevalence among the captive macaques at this facility was 25.9% (indirect fluorescent antibody titer greater than or equal to 1:16). Followup documented infection of 24.4% of initially seronegative animals and 8.7% of initially seropositive monkeys. Being held in a gang cage versus a single cage was found to be a significant risk factor for subsequent virus infection, and the presence of IFA antibody was shown to predict protection. This study documents unequivocally for the first time the presence of an Ebola-related filovirus in Asia.

Animals↗
PubMed1991

Hydrochlorothiazide versus spironolactone: long-term metabolic modifications in patients with essential hypertension.

The metabolic side effects of thiazide diuretics are believed to be responsible for the failure of thiazide diuretics to reduce cardiovascular morbidity in patients with hypertension. However, the decrease in the incidence of osteoporotic fractures that are associated with thiazide administration may be relevant in elderly patients with arterial hypertension. Spironolactone (SP) appears not to influence the metabolic risk profile of the patient with hypertension, and no studies have examined its effect on calcium metabolism. Therefore, in 22 patients with mild to moderate essential hypertension, the authors performed a parallel, randomized, double-blind, placebo-controlled study that compared the effects on serum urate and lipid, potassium, magnesium, and calcium metabolism of hydrochlorothiazide (HC) (mean [+/- SD] dose, 72 +/- 26 mg/d) and SP (144 +/- 53 mg/d) during a 52-week period. As compared with placebo, HC significantly increased serum urate and total cholesterol concentrations, and decreased serum potassium levels. SP did not affect serum urate or cholesterol levels but increased serum potassium concentrations. Neither diuretic significantly modified magnesium metabolism. Little changes were seen in serum calcium levels during HC or SP treatment, whereas urinary calcium excretion was significantly decreased by HC (mean decrease, 45%; P less than .01) or SP (40%; P less than .01). The authors conclude that SP, in addition to its potassium-sparing properties, has a calcium-sparing effect that may be beneficial for patients in whom reduction of urinary calcium excretion has a therapeutic value.

Adult↗
PubMed1991

Protective behavior of captopril on Hg(++)-induced toxicity on kidney mitochondria. In vivo and in vitro experiments.

Mercurials are known to induce morphological and functional modifications in kidney mitochondria. In this work we studied in vitro and in vivo the protective effect of captopril on the deleterious effect of Hg(++)-induced nonspecific membrane permeability changes to Ca++ and membrane de-energization. In vivo the administration of captopril prevented the toxic effects of mercury poisoning on membrane permeability, oxidative phosphorylation and Ca++ homeostasis. Moreover, captopril preserves kidney tissue morphology from Hg(++)-induced damage. The protective effect of captopril is most likely related to the existence of a sulfhydryl group in the drug.

Animals↗
PubMed1989

[Hemorrhagic syndrome associated with a factor VIII:C inhibitor in a patient with lymphoma].

Acquired hemophilia (idiopathic or secondary) is an uncommon clinical condition. A 70-year-old male had a severe hemorrhagic disorder, and an IgG inhibitor of the factor VIII:C was detected in plasma. During the acute phase he was treated with packed red blood cells, frozen fresh plasma and polyvalent immunoglobulins. The hemorrhagic features subsided but the circulating anticoagulant persisted. The administration of an activated prothrombin complex permitted to make the diagnosis of the underlying disease, a highly malignant T type lymphoma. During the treatment with corticosteroids and polychemotherapy the inhibitor activity disappeared.

Aged↗
PubMed1982

[Resistance of Crotalus durissus terrificus and Bothrops neuwiedii to the neurotoxicity of massive quantities of Crotalid venom].

The antitoxic potency of crude Crotalus durissus terrificus serum against crotalic venom is similar to that of a standard horse anticrotalic serum in protecting mice against 4 LD50, while the potency of Bothrops neuwiedii serum is 20% of the latter. Failure to form precipitin lines in immunodiffusion tests suggests that the antitoxic factors present in the sera from both species are not immunoglobulins. It is, therefore, probable that crotoxin is not neutralized by an antigen-antibody reaction, but rather by formation of inactive complexes with specific serum components. Resistance to the venom is not reciprocal, since specimens of C. d. terrificus die after the injection of similar amounts of B. neuwiedii venom, which are tolerated by the homologous species.

Animals↗