Gentamicin-induced increases in cytosolic calcium in pig kidney cells (LLC-PK1)

LLC-PK1 cells, an established epithelial cell line derived from pig kidney, were tested as a model system for assessing the role of calcium in gentamicin-induced nephrotoxicity. Cell viability was evaluated by a vital dye exclusion procedure, and intracellular free calcium [Ca2+]i was measured employing Fura-2 fluorescence. Exposing cell suspensions (10(6)/ml) to concentrations of the drug, which had no apparent effect on viability, produced a rapid and prolonged increase in intracellular [Ca2+]. The perturbation of calcium homeostasis could be blocked by the addition of mepiperphenidol, an inhibitor of the organic cation transport system. We propose that LLC-PK1 cells are an appropriate model to study drug-induced nephrotoxicity. Gentamicin disrupts calcium homeostasis and causes plasma membrane alterations. Since mepiperphenidol blocked the gentamicin-induced Ca2+ increases, the data suggest that aminoglycosides enter the cell via the organic cation transporter.     

Quantitation of photochemically induced focal cerebral ischemia in the rat

This study was carried out with a recently developed model of focal cerebral ischemia in the rat based on the photochemical induction of thrombotic stroke using the dye Rose Bengal. We examined the change in the volume of the lesion and brain water content, in separate groups of rats, at different times (1, 4, 24, 72, and 168 h) after the induction of the ischemic lesion. The volume of ischemic damage increased rapidly between 1 and 24 h after the ischemic insult and decreased between 24 and 168 h. The lesion at 168 h was significantly larger than that following 1 h of ischemia and similar to that obtained at 4 h, suggesting that the maximum extent of tissue damage (without the involvement of significant edema) was reached within the first 4 h in this model. The enlargement of the lesion after 4 h correlated closely with changes in brain water content.     

Spinal MR findings in neurofibromatosis types 1 and 2.

PURPOSE: To evaluate the frequency and nature of spinal pathology, the frequency of clinically silent lesions, and the potential benefit of screening spinal MR in neurofibromatosis patients. PATIENTS AND METHODS: 28 neurofibromatosis type-1 (NF-1) patients and nine neurofibromatosis type-2 (NF-2) patients were studied with postcontrast spinal MR imaging. RESULTS: NF-1: One patient had a biopsy-proven low-grade glioma; five patients, intradural, extramedullary masses (N = 23); one patient, extradural masses (N = 2) (neurofibromas); 16 patients had bony abnormalities; and three patients thecal sac abnormalities. NF-2: Five patients demonstrated intramedullary masses (five/eight ependymomas); nine patients, intradural, extramedullary masses (meningiomas, schwannomas); and four patients, bony abnormalities. Eight/10 NF-1 and four/nine NF-2 patients had asymptomatic masses. CONCLUSION: Intradural disease is common, often asymptomatic, and often presents at a young age in NF-1 and NF-2 patients. Because of the propensity to develop significant asymptomatic as well as symptomatic intradural disease, screening of the entire spine with MR is recommended in both NF-1 and NF-2 patients.     

Fat embolism after liposuction

We present a case of adult respiratory distress syndrome (ARDS) after extensive liposuction. On the basis of fever, tachypnea, hypoxia, and ARDS occurring within 48 hours after surgery without evidence of cardiogenic pulmonary edema or sepsis, the etiology is believed to be fat embolism. Although liposuction is generally an effective and safe procedure, awareness of this life-threatening complication is important in order to institute prompt and appropriate treatment. Fat embolism must be differentiated from thromboembolism, as the treatment is different, and heparin is not indicated. It is recommended that training standards and guidelines be devised in order to reduce morbidity and mortality associated with this procedure.     

Cardiac calcification causing arrhythmia detected by technetium-99m MDP and SPECT

SPECT was used to identify a focal accumulation of cardiac calcification using Tc-99m MDP in a patient with an arrhythmia and known metastatic calcification elsewhere.     

Detection and partial purification of a potent mitogenic factor for human thyroid follicular cells.

Normal adult human thyroid follicular cells have an extremely limited proliferative capacity in vitro. No previously studied mitogen, including thyrotropin (TSH) or epidermal growth factor (EGF), has in our hands resulted in a significant improvement over the 3-4% nuclear [3H]thymidine pulse-labelling index (LI) obtainable with 10% fetal calf serum. Here we report the detection in the conditioned medium from a sub-clone of NIH3T3 fibroblasts of a mitogenic activity capable of increasing this response up to 10-fold, to an LI of over 20%, together with an even greater relative stimulation of mitotic activity. Preliminary characterisation has excluded EGF and TGF alpha, and demonstrated that the activity is bound reversibly by heparin-Sepharose, thus pointing to a member of the heparin-binding fibroblast- or hepatocyte-growth factor families. This material should have wide practical application in facilitating primary culture of follicular cells, and may reveal new mechanisms of stromal-epithelial interaction regulating normal and neoplastic thyroid growth in vivo.