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Biomedical subjects

M Stoller

Publications and source records attributed to M Stoller.

10 recordsLinked to original sources

Munchausen's syndrome: manifestation as renal colic.

Over a four-year period, 3 patients with manifestations of renal colic were identified to have Munchausen's syndrome. A review of these cases and the literature is undertaken to provide urologists with a greater understanding of the origin and treatment of this syndrome.

Adult↗

Laparoscopic pyelocaliceal diverticula ablation.

Pyelocaliceal diverticula are cystic urine collections within the renal parenchyma communicating with the collecting system. They occur in 0.2% to 0.5% of the population and often contain calculi. Flank pain is the most common complaint, and most lesions are diagnosed by intravenous urography. In the past, treatment has required open renal surgery, with potential loss of renal function, or prolonged percutaneous procedures. We propose surgical treatment of caliceal diverticula by laparoscopic unroofing and fulguration. The benefits include renal preservation as well as decreased morbidity and an earlier return to work for the patient.

Aged↗

Renal artery embolism: clinical features and therapeutic options.

Renal artery embolism is an infrequent but important cause of renal loss. However, due to its rarity and nonspecific presentation diagnosis is often delayed and occasionally missed. Furthermore, proper therapeutic intervention is not well established and aggressive surgical management is often ill-advised. We review the literature and present 3 cases seen recently at our institution. Selective intra-arterial infusion of thrombolytic agents appears to be the most favorable treatment. The duration of occlusion does not necessarily correlate with the return of renal function, and the degree of collateral renal blood flow can be important.

Adult↗

Palliative percutaneous and endoscopic urinary diversion for malignant ureteral obstruction.

We performed a retrospective analysis of 22 patients with malignant ureteral obstruction who underwent palliative urinary diversion by retrograde ureteral stenting or nephrostomy tube placement. The average duration of survival after diversion was 526 days and was unrelated to tumor type, patient's age or sex, renal function, or indications for diversion. As a group, patients without previous hormonal or chemotherapy survived longer. Morbidity related to the urinary diversion was low. The majority of patients (77%) were discharged from the hospital, and this group spent 86 percent of their survival time at home. We conclude that modern palliative urinary diversion can be performed with low morbidity and can result in long-term survival and improved quality of life. Predictions or assumptions concerning survival of individual patients should be made with caution.

Adult↗

Obstructive nephropathy: evaluation with dynamic Gd-DTPA-enhanced MR imaging.

The potential of dynamic gadolinium diethylenetriaminepentaacetic acid (DTPA)-enhanced magnetic resonance (MR) imaging for the examination of obstructive nephropathy was analyzed in 27 subjects (five healthy subjects, seven patients with dilated nonobstructed kidneys, six patients with acute obstruction, and nine patients with chronic obstruction) with use of a 1.5-T magnet. Morphologic findings were compared with quantitative analysis of temporal changes in signal intensity. Dynamic postcontrast images of the normal kidney demonstrated four phases of enhancement; cortical enhancement phase, early tubular phase, ductal phase, and excretory phase. The pattern of enhancement in dilated nonobstructed kidneys was similar to that in normal kidneys. In acutely obstructed kidneys, cortical enhancement was similar to that in normal kidneys (17% increase), but medullary enhancement was higher than normal, resulting in diminished corticomedullary differentiation. The early tubular phase was prolonged (until 2.5 minutes after injection), with delayed appearance of the ductal and excretory phases. In chronically obstructed kidneys, the increase in cortical intensity was less than that in normal kidneys (13% increase). The early tubular phase was prolonged, and the ductal phase was diminished or absent.

Acute Disease↗

Cerebral metabolic studies in situ by 31P-nuclear magnetic resonance after hypothermic circulatory arrest.

Cerebral high energy phosphates were studied in the intact rabbit brain using nuclear magnetic resonance spectroscopy. The effect of hypothermia on degradation kinetics in total ischemia due to circulatory arrest was examined, measuring phosphocreatine, adenosine triphosphate, and inorganic phosphate as a function of time at three different temperatures (35, 24, 21 degrees C). Phosphocreatine- and ATP-decays followed single exponential functions at all three temperatures. The half-life times increased by approximately a factor of three upon lowering the temperature from 35 to 21 degrees C with activation energies of 15-20 kcal/mol, which corresponds to values of Q10 between 2.4 and 3.2. In the temperature range studied, no critical temperature was found below which metabolism would stop completely. We conclude that nuclear magnetic resonance spectroscopy allows, in the intact animal, quantitative assessment of the influence of hypothermia on energy metabolism in the brain. This influence is a major concern in the field of cardiac surgery in infants and children who are often operated in total circulatory arrest under deep hypothermia.

Adenosine Triphosphate↗

The role of plastoquinone and beta-carotene in the primary reaction of plant photosystem II.

Extraction of Triton Photosystem II chloroplast fragments with 0.2% methanol in hexane for 3 h results in the removal of 90 to 95% of the plastoquinone in the original preparation. The extracted fragments (chlorophyll:plastoquinone ratio, 900: 1) showed no P-680 photooxidation at 15 K after a single laser flash. The extracted fragments also showed no light-induced C-550 absorbance change at 77 K. Reconstitution of the primary reaction of Photosystem II, as evidenced by restoration of low-temperature photooxidation of P-680, could be obtained by the addition of plastoquinone A but not by the addition of beta-carotene. The addition of beta-carotene plus plastoquinone A restored the C-550 absorbance change. These results indicate that plastoquinone functions as the primary electron acceptor of Photosystem II and that beta-carotene does not play a direct role in the primary photochemistry but is required for the C-550 absorbance change.

Carotenoids↗

Initial experience with mesocaval H grafts: comparison with other portosystemic shunts.

Two policies concerning portosystemic shunt for bleeding esophageal varices were compared. In 18 patients, splenorenal or portocaval shunts were performed according to anatomic and hematologic considerations. In 13 patients, only mesocaval H grafts were performed. In the latter group, more patients had poor liver reserve and required urgent surgery. Accordingly, early and late mortality and morbidity were higher in these patients. the technical ease of performance of the mesocaval H graft did not cancel out increased risk in poorer candidates for surgery.

Adult↗