Enhancing effect of electric stimulation on cytotoxicity of anticancer agents against rat and human glioma cells

Electropermeabilization, or electroporation, has been used to deliver genes or drugs into the cytoplasm through micropores in the cell membrane caused by electric stimulation. The cytotoxic effect of a combination of anticancer agents with electric stimulation on rat C6 and human T98G glioma cells was examined in vitro. Electric pulses of 100 microsec square waves (eight cycles at 1 Hz) at various electric fields were delivered to C6 or T98G glioma cell suspensions in combination with several anticancer agents. Cell growth was evaluated 48-72 h after treatment. Measurement of cell lysis by electric stimulation was used to assess the optimum field strength for electroporation. Electric stimulation enhanced significantly the cytotoxicity of bleomycin to both C6 and T98G cells by more than 1000-fold using an electric field of 1750 V/cm for C6 cells and 1000 V/cm for T98G cells. The enhancement disappeared when bleomycin concentration was reduced to 100 pg/ml. The cytotoxicity of carboplatin was weakly but significantly enhanced by electric stimulation when a high dose of carboplatin was used. However, there was no enhancement of the cytotoxicity of nimustine hydrochloride (ACNU), etoposide, and vincristine. These results indicate that the combination of bleomycin and electroporation is the most potent candidate for electrochemotherapy in vivo.     

Intestinal IgA deposition in Henoch-schönlein purpura with severe gastro-intestinal manifestations

Abstract In patients with Henoch-Schönlein purpura (HSP) presenting with severe gastro-intestinal (GI) symptoms, IgA deposition was studied in endoscopically obtained mucosal biopsies. A total number of 11 patients (male, 7; female, 4) were enrolled in this study; 7 patients underwent upper GI endoscopy and biops 1 underwent sigmoidoscopy and 3 underwent both. Upper GI endoscopy in each patient showed various mucosal changes including redness, petechiae, erosions, and ulcerations, most predominant in the second part of the duodenum. Sigmoidoscopy demonstrated no abnormality in two of four patients. Intestinal deposition of IgA was positive in 7 of 11 patients with HSP. Histological examination showed non-specific inflammation of varying degrees in each patient, but no small vessel vasculitis was observed. IgA deposits were seen in only 2 of 23 control subjects with various GI diseases. Positive rate of IgA deposition per patient was significantly higher in patients with HSP than in controls (P<0.005).Conclusion IgA deposition in the GI tract, as in the skin kidneys, is characteristic of HSP. Intestinal IgA deposition complements the diagnostic criferia of HSP.Presented in part at the 4th Pan-Pacific Congress of Paediatric Gastroenterology and Nutrition, Tokyo, September 1994     

Fluctuations of the Hemodynamic Derivatives During Left Ventricular Assistance Using Oscillated Blood Flow

Abstract: To analyze the autonomic nervous system during left heart bypass with a vibrating flow pump (VFP), fluctuations in hemodynamic derivatives were evaluated by the spectral analysis method using fast fourier transform methodology. After the left pleural cavity was opened through the fourth intercostal space under general anesthesia, a VFP was implanted as the left heart bypass device in chronic animal experiments using 3 healthy adult goats. Hemodynamic parameters with and without VFP assistance were recorded on magnetic tape in awake animals and were analyzed by computer through an analog to digital convertor. Power spectral analysis was performed on a beat-to-beat basis for the evaluation of the fluctuations. During left heart bypass with the VFP, Mayer wave fluctuations were decreased significantly although respiratory waves were not changed significantly. These results suggest that sympathetic nervous system modulation was changed under the influences of the left heart bypass with VFP. By using this analysis methodology, truly physiologic ventricular assistance may be achieved.     

Overexpression of Rad23 confers resistance to methylmercury in saccharomyces cerevisiae via inhibition of the degradation of ubiquitinated proteins

We report here that overexpression of Rad23, a protein related to the ubiquitin-proteasome system, renders yeast cells resistant to methylmercury. Rad23 has three domains: two ubiquitin-associated (UBA) domains that bind to the multiubiquitin chain of ubiquitinated proteins and a single ubiquitin-like (UbL) domain that binds to proteasomes. To examine the mechanism of acquisition of methylmercury resistance that is induced by overexpression of Rad23, we expressed variants of Rad23 in which one or the other of the two types of domain was defective in yeast cells. In cells that overexpressed full-length intact Rad23, we detected elevated levels of intracellular ubiquitinated proteins, and the cells were resistant to methylmercury. In contrast, cells that overexpressed Rad23 with a defective UBA domain were not resistant to methylmercury and contained control levels of ubiquitinated proteins. Yeast cells that overexpressed Rad23 with a defective UbL domain exhibited enhanced resistance to methylmercury and contained even higher levels of ubiquitinated proteins than cells that overexpressed intact full-length Rad23. Rad23 is known to have two mutually contradictory functions. It suppresses the degradation of ubiquitinated proteins by proteasomes via a mechanism mediated by the UBA domains, and it enhances the degradation of ubiquitinated proteins via a mechanism that is mediated by the UbL domain. Therefore, our findings suggest that Rad23 might induce resistance to methylmercury in yeast cells by suppressing the degradation of proteins that reduce the toxicity of methylmercury via a UBA domain-mediated mechanism.     

Changes in distribution of mercury and selenium in soluble fractions of rabbit tissues after simultaneous administration

The existing states of mercury and selenium in the blood and in soluble fractions of perfused rabbit liver and kidney were studied by gel filtration on Sephadex G-200 1 hr or 24 hr after intravenous injection of mercuric chloride and/or sodium selenite. Both mercury and selenium in the plasma and stroma-free hemolysate were found to exist in the high-molecular weight fraction following simultaneous injection of mercuric chloride and sodium selenite. Patterns in gel filtration of the plasma and the stroma-free hemolysate did not show any significant change between 1 hr and 24 hr after the administration. A similar tendency as described above was obtained with the liver-soluble fraction at 24 hr after injection of mercuric chloride and sodium selenite. A possible role of the high-molecular weight complex, which is quickly formed by the interaction of mercury and selenium in blood stream, in decreasing the acute renal toxicity of inorganic mercury is discussed.     

Three-dimensional reconstruction of the human semicircular canals and measurement of each membranous canal plane defined by Reid's stereotactic coordinates

OBJECTIVES: Equations for estimating the planar relationships of the human semicircular canals were devised by Blanks et al from a dissected bony labyrinth in a human skull. However, a similar study on the membranous semicircular canal planes has never been published. METHODS: In this study, the angle between each membranous canal plane and Reid's stereotactic horizontal plane was measured on serial histologic sections of 7 temporal bones from Japanese adults. We reconstructed the 3 semicircular canals by computer-aided 3-dimensional analysis. The angles between each pair of both bony and membranous canal planes were measured. RESULTS: In the bony labyrinth, the angles between the 2 canal planes of the lateral-anterior, anterior-posterior, and lateral-posterior pairs were 90.51 degrees +/- 2.98 degrees (mean +/- SD), 91.70 degrees +/- 1.85 degrees, and 94.52 degrees +/- 3.32 degrees, respectively. The angles between the 2 membranous canal planes of the lateral-anterior, anterior-posterior, and lateral-posterior pairs were 90.05 degrees +/- 4.74 degrees, 91.03 degrees +/- 2.93 degrees, and 91.92 degrees +/- 5.22 degrees, respectively. CONCLUSIONS: The data from our study of the membranous labyrinth showed that the angles between each canal plane and the others were much closer to 90 degrees than was found by Blanks et al for the bony labyrinth.     

Delivery of a healthy newborn using vitrified zygotes that developed from <Emphasis Type="Italic">in vitro</Emphasis> matured oocytes retrieved from a patient with polycystic ovarian syndrome

The aim of this study is to evaluate vitrified zygotes, which were developed from in vitro matured oocytes that were retrieved from a patient with polycystic ovarian syndrome. Oocyte retrieval was performed on day 15 following withdrawal bleeding. The oocytes were incubated for 24 h in human tissue culture medium (TCM)-199 maturation medium supplemented with 20% filtrated-mixed patients follicle fluid, follicle stimulating hormone (FSH), and human chorionic gonadotropin (hCG). A total of four immature oocytes were collected. Two of the four oocytes (50.0%) developed to the metaphase-II stage and, subsequently, two fertilized oocytes were vitrified at the pronuclear stage because a very thin endometrium was not conducive for transfer. One of the two vitrified zygotes was thawed and developed to a 4-cell cleavage stage embryo within 24 h. Subsequent to the embryo transfer, a healthy newborn was delivered. A successful delivery was ensued by using vitrified zygotes from an anovulatory woman with polycystic ovarian syndrome. (Reprod Med Biol 2003; 2 : 87–90)