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Biomedical subjects

M Davidman

Publications and source records attributed to M Davidman.

30 records · Page 2Linked to original sources
PubMed1979

Idiopathic, sustained, inappropriate secretion of ADH with associated hypertension and thirst.

A 15 year old girl presented with excessive thirst and hypertension (170/110 mm Hg). Biochemical investigations revealed serum sodium 118 meq/liter, serum osmolality 238 mosmol/liter, urine sodium 90 meq/liter, urine osmolality 700 mosmol/liter, persistenly elevated serum antidiuretic hormone (ADH) levels (5.8 to 11.9 pg/ml) and no obvious cause for the hypertension. The hypertension is, at least in part, volume-related, diminishing with fluid restriction. Features of gross water intoxication (e.g., confusion, coma) have not occurred. The etiology of the inappropriate secretion of ADH is not obvious but is not thought to be due to "resetting of osmoreceptors" as evidenced by failure to maximally dilute urine following a water load test and persistently elevated serum ADH levels. A similar patient described by Epstein and associates in 1962 is presently well with persistent features of inappropriate secretion of ADH.

Adolescent↗
PubMed1978

Proximal tubulare dysfunction associated with Burkitt's lymphoma.

Generalized aminoaciduria, uricosuria, glycosuria and phosphaturia were discovered in a patient with advanced Burkitt's lymphoma with renal infiltration. The literature is reviewed and three pathogenetic mechanisms are discussed. It is presumed that proximal tubular dysfunction in this case was related to the marked peritubular infiltrate causing cell mediated immunological injury or direct tubular destruction by tumor.

Adult↗
PubMed1978

Trace elements in kidney stones from three areas in the United States.

A large number of trace elements has been found in calcium stones (whewellite, weddellite, and apatite) and in struvite. Significantly fewer elements, with lower abundances, are found in uric acid and cystine. With the exception of four trace elements (lead, silicon, strontium, and zine), the trace element assemblages are identical in the oxalates (whewellite and weddellite); struvite is also similar but with notable exceptions. In general, apatite contains approximately twice the level of trace element abundances as do the oxalates. This study is based on the distribution of 20 elements in 186 mimeralogically identified urinary calculi from three generalized areas of the United States (northeast, southeast, and midwest). In general, there is no statistical difference in the trace element assemblages of mineralogically identical stones from the three areas.

Aluminum↗
PubMed1973

A definition of proximal and distal tubular compliance. Practical and theoretical implications.

Micropuncture studies were carried out in the rat to evaluate the in situ distensibility characteristics of the proximal and distal tubules under a variety of experimental conditions. In the first phase, we determined the response of tubular diameter (D) to changes in tubular pressure (P) induced by partially obstructing single tubules. The response observed under these conditions (i.e., when interstitial pressure is presumed to be constant) has been defined as the compliance of the tubule. Over the range of tubular pressures studied (10-35 mm Hg for the proximal tubule, 5-25 mm Hg for the distal tubule) the compliance characteristics of the proximal and distal tubule were found to be markedly different; the proximal tubular pressure-diameter relationship was linear, DeltaD/DeltaP = 0.45 mum/mm Hg, whereas the distal pressure-diameter relationship was curvilinear, DeltaD/DeltaP = c(-0.1xP+2.2). In the second phase we used the compliance data to construct a series of theoretical pressure-diameter curves that define the response of the tubule to increments in interstitial as well as intratubular pressure. These curves indicate that changes in distal diameter should provide a sensitive index of a rise in interstitial pressure under conditions in which the transtubular pressure gradient is increased by a small amount, but that proximal diameter should provide a more sensitive index of changes in interstitial pressure when the transtubular pressure gradient is increased by a large amount. In subsequent experiments in which furosemide was administered, we observed that the pressure-diameter relationships for both the proximal and distal tubule were indistinguishable from the compliance curves, a finding consistent with the interpretation that interstitial pressure was not appreciably changed from control. By contrast, when mannitol was administered, both proximal and distal tubular pressure-diameter relationships were significantly altered in a fashion consistent with a large increase in interstitial pressure. Neither with furosemide nor mannitol administration did it appear likely that significant changes in tubular compliance could account for the observed behavior of the tubule.Finally, we propose that a knowledge of tubular compliance will be useful in exploring the interrelationships between tubular and peritubular pressures, tubular anatomy, and transtubular ionic permeability. Recent studies linking changes in the geometry of lateral intercellular spaces of the tubule to changes in passive ion movement suggest that an investigation of such anatomical-functional correlates should be productive.

Animals↗
PubMed1966

Intermittent hemodialysis in terminal chronic renal failure.

Seven patients with chronic renal failure underwent intermittent hemodialysis for five to 37 months (111 patient-months on a twice-weekly basis) employing arteriovenous Teflon-Silastic cannulas and the modified two-layer Kiil hemodialyzer. A single-pass 37 degrees C. dialysate system has been used. One patient died of an indirectly related cause. All other patients have been successfully rehabilitated and now carry on normal activity of moderate sedentary type. Complications included recurring infection and clotting of arteriovenous cannulas. Hypertension and anemia were common complications requiring careful control. Peripheral neuropathy was noted in five of the seven patients but was of clinical significance in only one patient. Metastatic calcification, osteoporosis and urolithiasis also occurred in this patient. Peptic ulcers with hemorrhage developed in two patients. The degree of rehabilitation and psychological adjustment achieved by this group of patients strongly indicates the need for expansion of dialysis facilities and further research into the medical and economic aspects of dialysis.

Adolescent↗
PubMedDate not supplied

Wegener's granulomatosis and relapsing polychondritis: a case report.

Relapsing polychondritis, a rare disorder characterized by inflammation of cartilaginous tissue, is often associated with vasculitic features. Wegener's granulomatosis is an uncommon form of vasculitis, usually responsive to treatment with cyclophosphamide. A 59-yr-old man with relapsing polychondritis, initially well controlled by corticosteroid therapy, developed pulmonary infiltrates and glomerulonephritis. After pathological confirmation of Wegener's granulomatosis, cyclophosphamide therapy was instituted and remission achieved.

Cyclophosphamide↗