Microsurgical sutures with non-transfixing staples. An experimental study of 15 rat aortas

This study, conducted in rats, studied a new system of anastomosis, by nontransfixing clips, pinching each edge of the artery with minimal trauma. Histological examinations were performed at one week and one month in order to investigate the vascular wall in the line of anastomosis. Clinical application of this procedure was undertaken in view of the encouraging and satisfactory results obtained.     

Can reduction in hypertriglyceridaemia slow progression of microalbuminuria in patients with non-insulin-dependent diabetes mellitus?

The objective of this study was to investigate whether reduction in hypertriglyceridaemia is associated with a slower rate of progression of microalbuminuria in patients with non-insulin-dependent diabetes mellitus (NIDDM). Fifteen normotensive NIDDM patients with hypertriglyceridaemia (> 2.5 mmol L-1) and microalbuminuria were randomly selected to receive either placebo (eight patients) or gemfibrozil 600 mg b.i.d. (seven patients). Progression of microalbuminuria was assessed during a 12-month follow-up period with measurements, consisting of blood tests and triplicate 24-h urine collections, at 1, 3, 6, 9 and 12 months. All but one patient in the treatment group showed a favourable response (> or = 20% reduction) of hypertriglyceridaemia to gemfibrozil. One patient in the placebo group showed a spontaneous reduction in triglyceride levels. Progression of microalbuminuria was lower, although not statistically significantly so, in the treatment group (36%) than in the placebo group (65%). In the group with > or = 20% reduction in triglyceride levels, progression of MA was significantly lower than in the group with stable or increasing triglyceride levels (+1%, range -56% to +49% vs. +97%, range -35% to +202% respectively) (P = 0.03). Continued follow-up data of patients switching from placebo to gemfibrozil after the trial further support the role of serum triglyceride reduction in stabilizing albumin excretion. In conclusion, the results indicate that, in microalbuminuric NIDDM patients, effective treatment of dyslipidaemia could be associated with stabilization of urinary albumin excretion.     

Novel cell imaging techniques show induction of apoptosis and proliferation in mesothelial cells by asbestos

We developed in situ dual-fluorescence detection techniques for measuring apoptosis and proliferation simultaneously in single dishes of cells. The deoxyribonucleic acid (DNA)-specific labeling method, terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate nick-end labeling (TUNEL), first was used in conjunction with a 4',6-diamidino-2-phenylindole (DAPI) counterstain to detect and measure morphologic characteristics of apoptotic rat pleural mesothelial (RPM) cells isolated from Fischer 344 rats and exposed to 300 microM hydrogen peroxide (H2O2). For this purpose, 100 TUNEL-positive nuclei were measured while being viewed with DAPI counterstaining for area, perimeter, longest diameter, and average diameter, using imaging software and an image-collection apparatus. We then exposed cells to a range of concentrations of crocidolite asbestos and putative apoptotic and mitogenic agents. Exposure to crocidolite asbestos (5 microg/cm2) caused a striking dose-dependent apoptotic response at 24 h, 48 h, and 72 h. The nonfibrous crocidolite analogue riebeckite failed to induce apoptosis. At 24 h, tumor necrosis factor-alpha (TNF-alpha) (10 ng/ml) caused an increase in apoptotic nuclei. A second method, utilizing an antibody to 5'-bromodeoxyridine (BrdU) and oxazole yellow homodimer (YOYO), showed a dose-dependent increase in proliferation occurring in cells exposed to asbestos (5 microg/cm2) at 48 h and 72 h. In addition, increased numbers of rat pleural mesothelial (RPM) cells exposed to 12-O-tetradecanoylphorbol-13-acetate (TPA), TNF-alpha, and epidermal growth factor (EGF) exhibited incorporation of BrdU at these time points, although total numbers of cells per unit area were unchanged. Results indicate a dynamic balance between apoptosis and increased DNA synthesis after exposure of mesothelial cells to asbestos.     

A humanized form of a CD4-specific monoclonal antibody exhibits decreased antigenicity and prolonged plasma half-life in rhesus monkeys while retaining its unique biological and antiviral properties

Certain monoclonal antibodies (MAbs) directed against CD4 can efficiently block HIV-1 replication in vitro. To explore CD4-directed passive immunotherapy for prevention or treatment of AIDS virus infection, we previously examined the biological activity of a nondepleting CD4-specific murine MAb, mu5A8. This MAb, specific for domain 2 of CD4, blocks HIV-1 replication at a post-gp120-CD4 binding step. When administered to normal rhesus monkeys, all CD4+ target cells were coated with antibody, yet no cell clearance or measurable immunosuppression occurred. However, strong anti-mouse Ig responses rapidly developed in all monkeys. In the present study, we report a successfully humanized form of mu5A8 (hu5A8) that retains binding to both human and monkey CD4 and anti-AIDS virus activity. When administered intravenously to normal rhesus monkeys, hu5A8 bound to all target CD4+ cells without depletion and showed a significantly longer plasma half-life than mu5A8. Nevertheless, an anti-hu5A8 response directed predominantly against V region determinants did eventually appear within 2 to 4 weeks in most animals. However, when hu5A8 was administered to rhesus monkeys chronically infected with the simian immunodeficiency virus of macaques, anti-hu5A8 antibodies were not detected. Repeated administration of hu5A8 in these animals resulted in sustained plasma levels and CD4+ cell coating with humanized antibody for 6 weeks. These studies demonstrate the feasibility of chronic administration of CD4-specific MAb as a potential means of treating or preventing HIV-1 infection.     

Enhanced cochlear responses after sound exposure

Alternating potentials produced in Hensen's cells of Mongolian gerbils by sinusoidal stimuli were enhanced or depressed after exposure to broad-band sound of moderately high intensity, depending on exposure- and stimulus intensities. Since Hensen's cell responses have been shown to be identical in phase and directly proportional in magnitude to outer hair cell (OHC) responses (Oesterle, E.C., Dallos, P., 1989, J. Acoust. Soc. Am. 86 (3), 1013-1032.; Zwislocki, J.J., Slepecky, N.B., Cefaratti, L., Smith, R.L., 1992, Hear. Res. 57, 175-194), it was assumed that these changes were reflections of changes in OHC receptor potentials, which were of main interest. The indirect method of intracellularly recording the Hensen's cell potentials rather than OHC potentials was used to minimize damage to the organ of Corti and reduce technical difficulties associated with repeated recordings from OHCs. Continuous magnitude and phase transfer functions (TFs) were obtained before and after the exposure over a range of sound pressure levels (SPLs) extending from 40-90 dB by using frequency sweeps ranging from 0.125-18 kHz. Cochlear microphonic (CM) TFs were also acquired over the same frequency and intensity ranges for monitoring purposes. The exposure stimuli were set at 80, 86, 90 or 100 dB SPL for periods ranging from 10-40 min. When response enhancement occurred, it was most clearly seen in the peak of the transfer function determined at 90 dB SPL. Enhancement ranged from approximately 12-230% of the original peak. In contrast, control Hensen's cell recordings obtained over periods of up to 130 min revealed great response stability. In all reliable recordings, response enhancement was associated with a phase lead or no phase change. The strongest exposure stimuli tended to produce sensitivity loss accompanied by phase lag at the lower SPLs, in agreement with previous work in this laboratory (Zhang and Zwislocki, 1995). In some preparations, both sensitivity loss at lower SPLs and enhancement at higher SPLs occurred simultaneously, suggesting involvement of two different mechanisms.