Biomedical subjects
Publications and source records attributed to K Pak.
Computed tomography of an adult with an asymptomatic unilateral impalpable testis showed carcinoma of the intra-abdominal testis. We recommend computed tomography as a non-invasive technique in all patients with impalpable testes after puberty to detect tumors.
A case of hypertension secondary to unilateral hydronephrosis is reported. Renin levels were elevated in peripheral veins and in the renal vein draining the affected kidney. An infusion of angiotensin II analogue resulted in a decrease in blood pressure. After nephrectomy, blood pressure and peripheral plasma renin activity returned to normal. Renal vein renin and angiotensin II analogue studies were useful in the diagnosis and evaluation of curability by surgery in this case.
Twenty-one anti-cancer drugs have been tested for their ability to cause mutations in Salmonella typhimurium test strains in the Salmonella/microsome mutagenicity test. Nine of the 21 anticancer drugs showed this ability: cyclophosphmide, nitromin, thio-tepa, busulfan, 6-mercaptopurine, neocarzinostatin, daunomycin, adriamycin and estramustine phosphate. Seven of these 9 mutagenic drugs were injected continuously into the jugular veins of rats. Urine was collected through a cystostomy tube and tested for mutagenicity. The urine from rats treated with 6 of these 7 drugs was mutagenic. These were cyclophosphamide, nitromin, thio-tepa, neocarzinostatin, adriamycin and daunomycin.
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In an experimental evaluation with 14 paired cadaveric scapulae we found that the transacromial arthroscopy portal, used occasionally in the repair of superior labral lesions, will reduce the structural integrity of the acromion to approximately 60% (range 25% to 85%) of its original strength, thereby placing it at increased risk of fracture. These studies provide baseline biomechanical information and suggest that limited shoulder activity is indicated after use of this portal.
The influence of laminin-1 (LN) and tenascin-C (TN), extracellular matrix molecules expressed spatially and temporally along the neural growth route from spiral ganglion (SG) neurons to the cochlear sensory cells, was evaluated in cultured SG explants from postnatal day 4 rats. Increasing concentrations of LN resulted in a strong, dose-dependent increase in the length of neurites and in a higher number of neural processes, while varying TN concentrations had relatively minor effects on both parameters. The results suggest differential receptor activation by LN and TN. When explants grown on LN were treated with Kistrin, an inhibitor of the alphavbeta3 integrin, the LN-induced increase in neurite length was reduced in a dose-dependent manner. However, the number of extending neurites was not affected, indicating that different receptors mediate this response, perhaps by increasing neuronal survival.