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Biomedical subjects

I Singer

Publications and source records attributed to I Singer.

At least 55 records · Page 3Linked to original sources
PubMed1986

Acute renal failure in sickle-cell disease.

Two patients with reversible acute oligoanuric renal failure in the setting of sickle-cell crisis are presented. The renal failure could not be attributed to volume depletion, urinary tract obstruction, or exogenous nephrotoxins. There were several features in each case that suggested the presence of nontraumatic rhabdomyolysis. The possible role of pigmenturia in the pathogenesis of the reversible renal failure in sickle-cell crisis is discussed.

Acute Kidney Injury↗
PubMed1986

Profound hyperkalemia without electrocardiographic manifestations.

Although the electrocardiogram (ECG) is not considered a reliable indicator of mild to moderate hyperkalemia, profound elevations of serum potassium concentration generally produce classic ECG manifestations. We report two cases of severe hyperkalemia (greater than 9.0 mEq/L) in which the ECGs did not reveal the expected manifestations of hyperkalemia. Thus, even with profound serum potassium elevations, the ECG cannot reliably be used to exclude the presence of hyperkalemia or to monitor therapy designed to lower the serum potassium concentration.

Aged↗
PubMed1985

Demeclocycline-induced natriuresis and renal insufficiency: in vivo and in vitro studies.

We examined renal function and Na+ balance in a patient with congestive heart failure who was treated with demeclocycline (DMC) on three separate occasions under strict metabolic balance conditions. Natriuresis and reversible renal insufficiency, which could not be explained solely on the basis of negative Na+ balance, developed on each occasion. In contrast to reports of an association between elevated serum DMC levels and renal insufficiency in patients with cirrhotic edema, the renal insufficiency in this patient with cardiac edema occurred in the absence of high DMC levels. Consequently, markedly elevated serum DMC levels do not appear to be a prerequisite for the development of natriuresis or renal insufficiency in edematous patients receiving this drug. In an attempt to clarify the mechanism of the natriuresis, we also examined the effects of DMC on Na+ transport in an in-vitro model system, the toad urinary bladder. DMC inhibited aldosterone-stimulated Na+ transport, but had no effect on Na+ transport when the latter was jointly stimulated by ADH and theophylline. Despite this selective inhibition of the natriferic effect of aldosterone in vitro, it is unlikely that such a mechanism completely accounts for the natriuresis observed in-vivo since the natriuresis is generally of large magnitude and is usually accompanied by some degree of kaliuresis, and DMC had no consistent effect on urinary aldosterone excretion. Consequently, other mechanisms must be sought to explain the natriuretic effect of DMC in edematous patients. Likewise, mechanisms other than negative Na+ balance (perhaps primary alterations in renal hemodynamics) must underly the development of renal insufficiency in such individuals.

Administration, Oral↗
PubMed1985

Gonococcal peritonitis in a patient treated with continuous ambulatory peritoneal dialysis (CAPD).

We report a case of gonococcal peritonitis in a sexually active female on continuous ambulatory peritoneal dialysis. The presumed route of entry into the peritoneal cavity was via the Fallopian tube. The episode responded rapidly to a standard antibiotic treatment protocol. Some episodes of culture-negative peritonitis may be caused by genital tract organisms which are not cultured by routine methods.

Adolescent↗
PubMed1985

Factors influencing erythrocyte sedimentation in patients with chronic renal failure.

Erythrocyte sedimentation was studied in stable patients with chronic renal failure free of complicating illnesses. The mean (+/- SD) Westergren erythrocyte sedimentation rate was 49 +/- 26 mm/hr in patients not receiving dialysis and 60 +/- 33 mm/hr in patients receiving hemodialysis. Both values are significantly higher than normal. Because anemia accelerates the Westergren determination, we restudied the patients with the zeta sedimentation ratio (ZSR), a method unaffected by hematocrit. In nine patients not receiving dialysis and 49 patients receiving hemodialysis, the ZSR was significantly higher than normal. The ZSR correlated positively with plasma fibrinogen concentration. Recombination experiments showed that the abnormal factor accelerating erythrocyte sedimentation was a constituent of plasma. Thus, erythrocyte sedimentation is accelerated in stable patients with chronic renal failure and a plasma factor, probably fibrinogen, is responsible. An elevated erythrocyte sedimentation rate in this population lacks diagnostic usefulness.

Blood Sedimentation↗
PubMed1984

The role of gallium-67 studies in the management of malignant melanoma.

This study was undertaken to assess the role of gallium-67 studies in the management of malignant melanoma. Gallium-67 studies were performed in 41 patients prospectively to determine the presence of regional lymph-node spread or distant metastatic disease. A high correlation was found in the assessment of lymph-node status between the results of the gallium-67 study and those of the histological examination. Distant metastases were demonstrated in brain, lung, bone, and liver. In three patients, lymphoscintigraphy was performed before the gallium-67 study in order to assess regional drainage; this may prove to be a very useful combination in determining treatment strategy, especially in patients with truncal melanoma.

Bone Neoplasms↗
PubMed1984

Blood-pool studies of the liver. Diagnostic patterns exist in cavernous haemangioma.

Hepatic haemangioma is the most common vascular abnormality of the liver occurring in 0.4% to 7% of reported autopsy series. Its diagnosis is critical, as biopsy of these lesions can lead to catastrophic results owing to uncontrolled haemorrhage. Hepatic angiography is normally used for diagnosis. Previous reports of attempts to confirm the diagnosis by non-invasive means such as ultrasound and computed tomography (CT) have shown these tests to be non-specific. The usefulness of the patient's own red blood cells labelled with technetium-99m (99mTc RBC) in the non-invasive diagnosis of hepatic haemangioma was investigated. After the intravenous injection of the isotope, flow, early static, and delayed static views were obtained. A flow study demonstrating decreased perfusion and a late blood-pool study showing local blood volume markedly greater than that of the normal liver were characteristic of haemangioma. 99mTc RBC studies are useful in the evaluation of focal defects in the liver when cavernous haemangioma is suspected. A diagnostic pattern is present in patients with cavernous haemangioma.

Adult↗
PubMed1984

Hyperchloremic metabolic acidosis after chlorine inhalation.

Chlorine gas inhalation is usually accompanied by pulmonary toxicity and hypoxemia; the associated acidemia, when present, has been attributed to lactic acidosis. This case report describes the development of hyperchloremic metabolic acidosis following accidental chlorine gas exposure. The mechanism postulated for the production of this acidosis is the absorption of hydrochloric acid following the reaction of chlorine gas with tissue water. This may be the first case of chlorine toxicity in which the mechanism of the acidosis has been determined.

Accidents, Home↗
PubMed1984

Radionuclide plethysmography and Tc-99m red blood cell venography in venous thrombosis: comparison with contrast venography.

Radionuclide plethysmography (RPG) is a new technique that uses Tc-99m labelled red blood cells to ascertain changes in venous volumes by detecting the change in counts in response to the inflation and deflation of proximal thigh cuffs. Diagnosis of ileofemoral venous occlusion is possible using this technique, which also provides kinetic data of venous outflow. A range of normal values was defined in 19 subjects for per cent change in venous capacitance and venous outflow. Twenty-one patients with suspected deep venous thrombosis were studied prospectively using RPG, radionuclide venography (RV), and contrast venography (CV) to establish the usefulness of RPG alone and in combination with RV in the diagnosis of deep venous thrombosis. RPG proved to be a reliable technique for the diagnosis of ileofemoral venous thrombosis (sensitivity, 91%; specificity, 100%). RV was less sensitive (73%) and less specific (93%) in diagnosing that condition. When RPG is used as the criterion for the detection of ileofemoral vein thrombosis and RV is used as the criterion for the detection of calf vein thrombosis, the combined techniques show improved sensitivity (92%) and specificity (93%) for the detection of all deep venous thromboses.

Adult↗
PubMed1983

Drug prescribing in renal failure: dosing guidelines for adults.

The data base for rational guidelines to safe, efficacious drug prescribing in adults with renal insufficiency are presented in tabular form. Current medical literature was extensively surveyed to provide as much specific information as possible. When information is lacking, however, recommendations are based on pharmacokinetic variables in normal subjects. Nephrotoxicity, important adverse effects, and special considerations in renal patients are noted. Adjustments are suggested for hemodialysis and peritoneal dialysis when appropriate.

Adult↗
PubMed1981

Subcellular localization of aldosterone-induced proteins in toad urinary bladders.

Paired toad urinary hemibladders were incubated with [35S]methionine in the presence (experimental) or absence (control) of aldosterone. Short-circuit current was used to monitor aldosterone-induced Na+ transport. Protein synthesis in epithelial cell subcellular fractions (cytosolic, microsomal, mitochondrial) was evaluated by gradient polyacrylamide gel electrophoresis and autoradiography. Aldosterone-induced proteins were identified in the cytosolic and microsomal fractions (70 000 and 15 000 daltons, respectively). These results represent the first demonstration of aldosterone-induced proteins in subcellular fractions of epithelial cells derived from single toad urinary hemibladders.

Aldosterone↗