Effects of a K+ATP channel opener, lemakalim, on systemic, coronary and regional vascular dynamics in conscious dogs: comparison with nifedipine, adenosine, nitroglycerin and acetylcholine

The systemic, coronary and regional vascular responses to the K+ATP channel opener lemakalim were compared to other potent vasodilators (i.e., nifedipine, adenosine, nitroglycerin and acetylcholine). Experiments were performed in 12 conscious dogs 2 to 4 weeks after implantation of aortic catheters and flow probes on the ascending aorta, left circumflex coronary, celiac, mesenteric, renal and iliac arteries, and solid-state miniature pressure gauges in the left ventricular cavity. Dose-response curves induced by bolus injection (i.v.) were examined. For doses that reduced total peripheral resistance by 22%, lemakalim reduced celiac (-28 +/- 2%), mesenteric (-24 +/- 3%), renal (-17 +/- 3%) and iliac (-18 +/- 3%) vascular resistances (i.e., by amounts similar to those observed with the other vasodilators, except for adenosine, which increased renal resistance). At these doses, lemakalim induced a greater decrease (-52 +/- 3%) (P < .05) in coronary resistance, as compared with nifedipine (-35 +/- 3%), adenosine (-38 +/- 3%), nitroglycerin (-25 +/- 2%) and acetylcholine (-32 +/- 3%). However, when near maximal vasodilation was elicited, adenosine elicited the greatest (P < .05) decrease in coronary resistance (-81 +/- 1%), as compared with lemakalim (-74 +/- 2%), nifedipine (-67 +/- 2%), nitroglycerin (-63 +/- 2%) and acetylcholine (-72 +/- 1%). Both the time to maximal increases in regional blood flow and the time for recovery in all vascular beds were significantly prolonged for lemakalim compared with the other vasodilators. Thus, the K+ATP channel opener lemakalim dilates the coronary bed out of proportion to other vascular beds, is relatively more potent at lower doses than other vasodilators and exhibits a delayed and more prolonged action in all regional vascular beds.     

The band areas of proteins determined by fluorescent scanning in the commercial automated gel electrophoresis apparatus

An automated gel electrophoresis apparatus, recently available commercially, allows one to follow the band during electrophoresis in real time, and lends itself therefore to an evaluation of bandwidth as a function of migration time (the dispersion coefficient), resolution and band shape. These determinations assume the constancy of band area with migration time and at various gel concentrations. The purpose of the present study was to verify these assumptions. Representative proteins and sodium dodecyl sulfate (SDS)-proteins, either natively fluorescent or fluorescein carboxylate labeled, were found to exhibit band areas which approach constancy as a function of migration time in both agarose and polyacrylamide gel electrophoresis, provided that (i) the protein concentration under the band was low enough to obviate self-quenching of fluorescence; (ii) the separation of the protein of interest from contaminants had progressed sufficiently during the time at which band areas were measured; (iii) the baseline under the peak was sufficiently well defined. However, band areas decrease with increasing gel concentration. Protein peaks exhibited leading and trailing tails. The ratio of the combined tail area to total area appeared to be near-constant at varying migration times. However, that ratio increases with increasing gel concentration. The tail area does not appear to be an artifact of fluorometric detection since it is reproduced upon fluorimetric analysis of the protein eluted from gel slices after electrophoresis. However, it may be due to photochemical destruction under the conditions of repetitive fluorometric peak detection.     

Bias and temperature dependence of homogeneous hot-electroninjection from silicon into silicon dioxide at low voltages

In this paper, new homogeneous hot-electron injection data at 300 K and 77 K is provided covering applied voltages from well below to well above the Si-SiO₂ barrier height, and a wide range of oxide fields. We found that, in contrast to the MOSFET case, homogeneous injection shows two different regimes for accelerating voltages below and above the barrier height. A simple interpretation of the data is proposed, and supported by Monte Carlo (MC) simulations of the injection experiment. Essentially, the two regimes are the signature of a marked transition between an electron population mostly heated by the electric field, and a tail population created by additional but less efficient energy gain mechanisms, leading to a sharp transition in the carrier distribution function. The details of the bias and temperature dependence of injection are then interpreted as the combined effect of tunneling and carrier distribution. Furthermore, possible implications on MOSFET gate currents are briefly discussed     

Peripheral nerve stimulation by time-varying magnetic fields

PURPOSE: A study was performed to assess the stimulation threshold for healthy adults using sinusoidally oscillating gradients. METHOD: One hundred thirteen healthy adults were examined in the study. ECG and physiological parameters were measured. All measurements were performed of both the head and the abdomen. The subjects were measured in the supine position with the region of interest positioned in the center of the gradient coils. The measurement was performed for three orthogonal, four oblique, and double oblique orientations. RESULTS: No volunteer reported painful, severe stimulation. The mean thresholds for peripheral stimulation in head and body measurement were similar: 85.5% of stimulation during examination of the head and 87.6% during measurements of the abdomen were reported when the y-gradient was used. CONCLUSION: The greatest frequency of reported stimulations occurs when the y-gradient is used. This was confirmed by the results and supports the hypothesis that orthogonal to the y-axis the body has its largest conductive loop, resulting in the strongest peripheral stimulation.     

Antiserum against Escherichia coli J5 contains antibodies reactive with outer membrane proteins of heterologous gram-negative bacteria

The binding of IgG in antiserum to Escherichia coli J5 to the surface of Enterobacteriaceae and to cell wall fragments released from serum-exposed bacteria was studied in a search for potentially protective epitopes other than lipopolysaccharide (LPS). IgG titers to multiple heterologous gram-negative smooth bacteria increased following incubation of the bacteria in serum and decreased following absorption with serum-exposed heterologous bacteria. IgG eluted from absorbing bacteria bound to at least three conserved bacterial outer membrane proteins (OMPs), but not LPS, as assessed by immunoblotting. The same OMPs were present in LPS-containing macromolecular cell wall fragments released by incubation of heterologous gram-negative bacteria in human serum. Part of the protection offered by J5 antiserum could be from binding of IgG to conserved OMPs at the bacterial surface or to OMPs in cell-wall fragments released from dying bacteria.     

Recovery of SDS-protein and DNA using commercial automated gel electrophoresis apparatus

Forty-seven children afflicted with acute leukemia were studied at the Tata Memorial Hospital Bombay to record the occurrence of oral manifestations prior to and during chemotherapy. Lymphadenopathy was the most frequent single finding suggestive of leukemia during head and neck examination. Gingival abnormalities, bleeding gums and oral mucosal pallor were the other findings on initial oral examination. Due to immunosuppression caused by the chemotherapy drugs oral mucosal ulcerations, uncontrolled herpes, candidiasis and pseudomoniasis were observed.     

Initial experiences with the MR "magnitude contrast angiography of the lower extremities

45 patients with occlusive peripheral vascular disease were examined by MR angiography in a retrospective study. A FISP 3D sequence was used by acquiring a rephased and a dephased data set. The individual slices were post-processed by using a maximum-intensity-projection algorithm. The MRA results of the popliteal and tibioperoneal arteries were compared to conventional or digital angiography. In comparing these techniques MR angiography cannot be accepted for pre- and postoperative staging of patients with occlusive peripheral vascular disease. In future new MRA techniques may be useful in postoperative staging of patients with peripheral vascular stenosis.