Biomedical subjects
Publications and source records attributed to S Vogel.
A case of massive digoxin ingestion with multiple arrhythmias, consisting of high grade A-V block and ventricular ectopy not responsive to lidocaine, is described. The arrhythmias ceased following administration of digoxin-specific Fab fragments. The patient improved and was transferred to the psychiatric unit.
Parasitologic, hematologic, and immunologic parameters were monitored in intact (nonsplenectomized), adult chimpanzees infected with a "chimp-adapted" strain of Plasmodium falciparum. Following primary and secondary injections of 10(9) P. falciparum-infected erythrocytes, each chimpanzee developed a low grade parasitemia (up to 1,000/mm3) and maintained the infection without evidence of eliminating the parasites. Hematologic and serum biochemical values, as well as the majority of immunologic parameters tested, remained unaltered in infected chimpanzees. However, 2 weeks after infection T cells from infected chimpanzees demonstrated an enhanced response in vitro to stimulation with the mitogen PHA, and monocyte phagocytic activity for antibody-coated erythrocytes (Fc-mediated phagocytosis) increased significantly. During malarial infection, apes developed a strong T cell proliferative response to P. falciparum antigens and monocytes showed enhanced phagocytic activity for P. falciparum-infected erythrocytes in the absence of immune serum. These results suggest that cellular immune mechanisms, especially macrophage activation, may help control, but not eliminate, P. falciparum malaria in chimpanzees.
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Percutaneous cholecystostomy was performed in 36 patients, of whom 22 patients with acute cholecystitis had decompression of the gallbladder and 14 patients with common duct obstruction had biliary decompression through the gallbladder. In almost all cases of acute cholecystitis, percutaneous cholecystostomy quickly confirmed the diagnosis and brought relief. Bile leakage occurred in one patient when catheter placement was performed under ultrasonic guidance alone; subsequent procedures were performed in a single step using an "accordion" catheter under fluoroscopic control following ultrasound localization. This technique has proved to be useful as both a diagnostic and therapeutic procedure.
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When a pacemaker cell is driven with a train of stimuli at a rate faster than its own, the termination of the drive is followed by a transient hyperpolarization, due to the activity of an electrogenic Na+-K+ pump. In this study, the effect of the halogenated ethers, enflurane and methoxyflurane, on postdrive hyperpolarization (PDH) was determined in cardiac Purkinje fibers. The fibers were removed from freshly excised canine hearts and superfused with a Tyrode's solution (containing 2.7 or 3.5 mM K+). The preparation was paced at 0.2 Hz before and after drives, and at 2 Hz during drives. Under control conditions, drives of 2 min produced a PDH of 5.5 +/- 0.2 mV. Enflurane (1.5-5%) significantly reduced the PDH. At 4 to 5%, enflurane reduced the PDH to a mean value of 42% of the control. Methoxyflurane was more potent than enflurane in affecting the PDH. At 0.5 to 0.75%, methoxyflurane reduced the PDH to 5% of the control. At higher (1-1.5%) concentrations of methoxyflurane, the PDH was converted to a depolarization, which varied between 0.5 and 8.0 mV. The PDH was restored to control levels within 10 to 20 min after washout of either anesthetic agent. Methoxyflurane (0.5 or 1%) enhanced the automaticity of spontaneously firing cells (2.35 mM K+ Tyrode's solution used). This positive chronotropic action coincided with a depolarization of 2 to 8 mV. Enflurane, at concentrations of 3 to 5%, gave similar results. On the action potential, methoxyflurane, at 1%, reduced the amplitude and duration (measured at 50% repolarization) of the plateau, and also the maximal upstroke velocity (+Vmax) of the rising phase.(ABSTRACT TRUNCATED AT 250 WORDS)
Detection of early diabetic nephropathy is necessary to postpone or even prevent progression of irreversible kidney damage by therapeutic measures. Beta 2-microglobulin (beta 2-MG) as a parameter of the glomerular filtration rate has been measured by immunoassay in the serum of 100 diabetic subjects, 50 insulin-dependent (IDD), and 50 noninsulin-dependent (NIDD) patients. The results are compared with endogeneous creatinine-clearance, serum creatinine concentration, and proteinuria and are related to different stages of diabetic retinopathy (RD). Normal values were obtained from 50 healthy age- and sex-matched subjects. A close correlation was found between beta 2-MG levels and endogeneous creatinine clearance. Thirty-nine diabetics revealed an elevated beta 2-MG (2.5 mg/l or higher), only 16 of whom had increased serum creatinine levels (1.4 mg/dl or higher). Significant differences of beta 2-MG were obtained between each group of patients with different stages of RD. A relevant difference of serum creatinine was found only between patients with normal eye fundus and advanced proliferative retinopathy, respectively. Without RD 26% of the patients revealed elevated beta 2-MG but normal creatinine values demonstrating a "latent nephropathy", just 8% showed an increase of both parameters. Of the diabetics with proliferative retinopathy 40% suffered from impaired kidney function proven by reduced creatinine clearance and by elevation of beta 2-MG and creatinine as well, 15% just revealed an increase of beta 2-MG with normal creatinine levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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The physical and dynamic condition of the liver-gall was examined. Flow-condition as the basis for intraoperational gallducts, already applied method of operation, was analysed. Our results show, the dynamic condition of liver-gall included in the law of Hagen-Poisseuille in the gall-flowing, do not have structured-viscosity and that the liver-gall is approximately identical to the Newton-fluid. A new method of examining the intraoperative flow and pressure measurement is suggested.
An ultrastructural study was made on the conjunctiva of a 38-year-old man with adult cystinosis. Intracellular cystine crystals were found not only in fibroblasts but also in numerous macrophages. Both fibroblasts and macrophages showed increased pinocytosis. Occasionally there were macrophage degenerations with extracellular cystine crystals present. Whether this increased macrophage reaction indicates a specific difference to childhood cystinosis remains a matter of speculation.
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Biochemical transformation of Ltk- cells with the herpes simplex virus thymidine kinase (tk) gene resulted in numerous TK+ colonies that survived selection in hypoxanthine-aminopterin-thymidine medium. Many of these TK+ cell lines switched phenotypes and reverted to the TK- state. In this report, we describe the biological and biochemical characteristics of three TK- revertant lines. One (K1B5) transiently expressed TK in the presence of bromodeoxyuridine, which selects for the TK- phenotype. Another TK- sibling (K1B6n) expressed TK only after removal from bromodeoxyuridine-containing medium. The last variant (K1B6me) lost the ability to switch to the TK+ phenotype, although it maintained the herpes simplex virus sequences coding for TK. Loss of the ability of K1B6me cells to express TK was correlated with extensive methylation of the sequence recognized by the restriction endonuclease HpaII (pCpCpGpG). After these cells were treated with 5-azacytidine, they regained the ability to clone in hypoxanthine-aminopterin-thymidine medium and reexpressed virus tk mRNA and enzyme. In addition, the HpaII sites that were previously shown to be refractile to enzyme digestion were converted to a sensitive state, demonstrating that they were no longer methylated.
Choline esters fail to depress developed tension or the maximum upstroke velocity (Vmax) of slow action potentials in embryonic chick ventricles, but they inhibit the stimulatory effect of the phosphodiesterase inhibitor methylisobutylxanthine (MIX). The mechanism by which the choline ester methacholine (MCh) counteracts the effects of MIX was examined in ventricular myocardium obtained from 7-day-old embryonic chicks. Four possible hypotheses were 1) that the physiological response to MCh is mediated by cyclic GMP, the production of which is potentiated by MIX; 2) that MCh acts by a mechanism independent of cyclic nucleotides; 3) that the binding of MIX to adenosine receptors induces sensitivity to MCh; or 4) that MCh acts by depressing basal cyclic AMP levels. Interactions between MCh, Angiotensin II and a nonmethylxanthine phosphodiesterase inhibitor (Ro 7-2956) were assessed by measuring tissue levels of cyclic nucleotides and the Vmax of slow action potentials. MCh significantly reduced the basal cyclic AMP level of embryonic chick ventricles, despite having no physiological effect. The results favor the final hypothesis and imply that MCh effects are mediated by inhibition of adenylate cyclase activity. The physiological response of the myocardium to a reduction in basal adenylate cyclase activity appears to be dependent on the initial tissue level of cyclic AMP.
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Effects of enflurane on myocardial electrophysiologic and contractile properties were examined by simultaneous measurement of action potentials (APs) and contractions in guinea-pig papillary muscle. Enflurane was administered in 1 to 6% concentrations in 5% CO2-95% O2 bubbled through the standard Tyrode's perfusing solution. After studying normal APs, slow APs were induced with 5 to 30 x 10(-8) M isoproterenol and/or 1 to 2 mM theophylline in partially depolarized muscles (typically -40 mV in 26 mM K+ media). AP characteristics and contractions measured during each enflurane application were analyzed. The maximum rate of rise (+Vmax) and amplitude of the normal AP was not depressed, although duration decreased in greater than or equal to 3% enflurane. In contrast, slow AP + Vmax declined significantly (P less than .05) to 90, 80 and 74% of control in enflurane concentrations of 2, 3 and 4%, respectively. Decrease in slow AP duration was significant only in 5 to 6% enflurane. In 1% enflurane, contractions declined to steady-state levels of 75 (fast AP) and 79% (slow AP) of control and fell to 20 (fast AP) and 35% (slow AP) in 4% enflurane. Enflurane concentrations of 2% and greater inhibit slow (Na+-Ca++) channels which mediate slow APs. This effect may be in part responsible for the negative inotropic effect of enflurane.
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