Tumor vascular signals in renal masses: detection with Doppler US

The vascularity of 49 renal masses (26 malignant and 23 benign lesions) was investigated with duplex Doppler ultrasound. Doppler signals obtained at the margins of renal masses were defined as "tumor signals" when the Doppler-shifted frequency of the lesion exceeded the frequency shift in the ipsilateral main renal artery. These exceeded 2.5 kHz with a 3-MHz insonating frequency. Among the 26 renal masses that subsequently proved to be malignant, tumor signals were obtained in 15 of 18 (83%) untreated renal cell carcinomas, in three of four Wilms tumors, and in two patients with metastases to the kidney, but not in the one patient with lymphoma. None of the 23 benign renal masses demonstrated tumor signals. Tumor vascularity in malignant lesions gives rise to abnormal, high-velocity, Doppler-shifted signals that can help in the differential diagnosis of renal masses.     

Detection of reactive oxygen species (ROS) and apoptosis in human fragmented embryos

In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture environment differs from in-vivo conditions in that the oxygen concentration is higher, and in such conditions the mouse embryos show a higher concentration of reactive oxygen species (ROS) in simple culture media. ROS are believed to cause damage to cell membranes and DNA fragmentation in somatic cells. This study was conducted to ascertain the level of H2O2 concentration within embryos and the morphological features of cell damage induced by H2O2. A total of 62 human oocytes and embryos (31 fragmented, 15 non-fragmented embryos, 16 unfertilized oocytes) was obtained from the IVF-embryo transfer programme. The relative intensity of H2O2 concentrations within embryos was measured using 2',7'-dichlorodihydrofluorescein diacetate by Quanti cell 500 fluorescence imaging and DNA fragmentation was observed with transmission electron microscopy and an in-situ apoptosis detection kit. The H2O2 concentrations were significantly higher in fragmented embryos (72.21 +/- 9.62, mean +/- SEM) compared to non-fragmented embryos (31.30 +/- 3.50, P < 0.05) and unfertilized oocytes (30.75 +/- 2.67, P < 0.05). Apoptosis was observed only in fragmented embryos, and was absent in non-fragmented embryos. Electron microscopic findings confirmed apoptotic bodies and cytoplasmic condensation in the fragmented blastomeres. We conclude that there is a direct relationship between increased H2O2 concentration and apoptosis, and that further studies should be undertaken to confirm these findings.      

Free radical scavengers, catalase and superoxide dismutase provide protection from oxalate-associated injury to LLC-PK1 and MDCK cells

PURPOSE: Current studies have provided evidence that exposure of renal epithelial cells to oxalate and calcium oxalate crystals induces lipid peroxidation and injures the cells. Since oxidant/antioxidant balance is likely to play a critical role, we determined the effect of antioxidant scavengers on production of free radicals and injury to LLC-PK1 and MDCK cells from exposure to oxalate (Ox) or Ox + calcium oxalate monohydrate (COM) crystals. MATERIALS AND METHODS: LLC-PK1 and MDCK cells were grown in monolayers and exposed to 1.0 mmol. Ox or 1.0 mmol. Ox + 500 microg. /ml. COM crystals for 120 or 240 minutes. We measured the release of lactate dehydrogenase (LDH) as a marker for cell injury and malondialdehyde (MDA) as a marker of lipid peroxidation. Superoxide and hydroxyl radicals were measured in the presence or absence of 400 U/ml. catalase, or superoxide dismutase (SOD). RESULTS: Exposure of LLC-PK1 cells to Ox resulted in a significant increase in MDA and release of LDH, which was further elevated when COM crystals were added. MDCK cells responded similarly to both challenges, but showed significantly less impact when compared with LLC-PK1 cells. Both treatments were associated with significant increase in the generation of hydroxyl and superoxide radicals by both cell types. In both cell lines, the addition of catalase or SOD significantly reduced the increase of MDA and release of LDH. CONCLUSIONS: Results of the present study indicate that both Ox and COM crystals are injurious to renal epithelial cells and the injury is associated with generation of free radicals. Cells of proximal tubular origin are more susceptible than those of distal tubules and collecting ducts. Free radical scavengers, catalase and SOD provide significant protection.     

Long-term natural history study of senile retinoschisis with implications for management

This is a long-term natural history study of 123 consecutive, nonselected patients (218 eyes) with senile retinoschisis examined periodically, while deliberately withholding all forms of treatment, for from 1 to 21 years (average, 9.1 years) so that the natural behavior and prognosis of this disease could be learned and reasonable recommendations for management could be formulated. The quadrant of maximal involvement was the inferior temporal and 74% of the lesions had posterior borders which were postequatorial. Senile retinoschisis was found to be primarily asymptomatic and nonprogressive. Current indications for treatment, treatment modalities, and complication rates published in recent literature are analysed. No case of symptomatic progressive retinal detachment occurred, but there were 14 cases of localized, nonprogressive and asymptomatic "schisis-detachment". Current indications for treatment of senile retinoschisis should be seriously reevaluated and reduced to one primary indication for treatment, namely symptomatic progressive retinal detachment.     

A Hodgkin cell-specific antigen is expressed on a subset of auto- and alloactivated T (helper) lymphoblasts

A Hodgkin cell-specific antigen detected by the monoclonal antibody Ki- 1 was found on T helper lymphocytes after activation by autologous and allogeneic stimulator cells. About 50% of lymphoblasts generated by auto- and alloactivation reacted with the antibody. In contrast, only less than 6% of lymphoblasts stimulated with Con-A, phytohemagglutinin (PHA), or protein A, and none of lymphoblasts activated by oxidative mitogenesis, expressed this antigen. Among several permanent cell lines tested, the K562, MOLT-4, HL-60, and EBV transformed B lymphoblastoid cells reacted with the Ki-1 antibody. The results may indicate possible relationships between the autoreactive subset of T lymphocytes and the pathogenesis of Hodgkin's disease.