The influence of the atrial natriuretic factor on venous tone in man

To assess the effect of the human atrial natriuretic factor (ANF) in vivo on human veins, a series of investigations was done on the dorsal hand vein of 11 healthy volunteers (ten men, one woman), aged from 25 to 49 years. In the case of intact veins the human ANF effect was evaluated by the "venoconstriction" test; on veins constricted by a reflex sympathetic discharge, the ANF effect was evaluated by the test of "venous reflexes", and on veins constricted with serotonin and angiotensin II by the "preconstriction" test. The results were expressed in venoconstrictive units (VCU). ANF was injected into the vein under study in increasing bolus doses (from 50 pg to 500 ng). The results indicate that this peptide did not affect either intact veins or these constricted by sympathetic discharge. On veins preconstricted with serotonin, ANF had a slight, statistically insignificant effect (848.57 +/- 378.67 VCU 30 sec before, compared to 670.00 +/- 460.25 VCU 30 sec after the injection of 50 pg; n = 7; p greater than 0.05), up to a maximal local dose of 500 ng. The same was true for the vein preconstricted with angiotensin II. It is concluded that the human atrial natriuretic factor has no significant influence on peripheral venous tone in man.     

Procedures to Characterize In Vivo and In Vitro Enantioselective Glucuronidation Properly: Studies with Benoxaprofen Glucuronides

The diastereoisomeric glucuronic acid conjugates of R/S-benoxaprofen are the major benoxaprofen metabolites and are found in urine at high concentrations. The conjugates of R- and S-benoxaprofen can be separated directly on a C₁₈ reversed-phase column using a mixture of acetonitrile and tetrabutylammonium hydroxide buffer, pH 2.5 (28:72, v/v), as the mobile phase. The k values of S- and R-benoxaprofen glucuronides are 57.5 and 63.0, respectively. Diluted urine or deproteinized plasma samples were injected without further treatment. With fluorescence detection at 313/365 nm, quantifiable limits of 50 ng equiv./ml were found for the conjugates. The intra- and interday variability was below 12%. Utilizing this analytical procedure it is possible to characterize enantioselective glucuronidation both in vivo and in vitro. For in vitro procedures, apparent rates of formation and the R/S ratio may be substrate (benoxaprofen) and cosubstrate (UDPGA) dependent. Moreover, enantioselective cleavage of the formed benoxaprofen glucuronides by alkaline hydrolysis, hydrolytic enzymes, and acyl migration must be controlled for both in vitro and in vivo studies since R-benoxaprofen glucuronide is degraded faster than the S-diastereomer under certain conditions.     

Sigmoidin F, a new prenylated flavonoid from Erythrina sigmoidea

Sigmoidin F, a new prenylated flavanone, as well as abyssinone IV and 5,7,4'-trihydroxy-3'-methoxy-5'-(1"-prenyl) flavonone have been isolated from the stem and bark of Erythrina sigmoidea. The structure of 1 has been confirmed by a combination of 1H-nmr and other spectroscopic techniques.     

Development of immunofiltration assay by light addressable potentiometric sensor with genetically biotinylated recombinant antibody for rapid identification of Venezuelan equine encephalitis virus

A genetically biotinylated single chain fragment variable antibody (scFv) against Venezuelan equine encephalitis virus (VEE) was applied in a system consisting of an immunofiltration enzyme assay (IFA) with a light addressable potentiometric sensor (LAPS) for the rapid identification of VEE. The IFA involved formation of an immunocomplex sandwich consisting of VEE, biotinylated antibody, fluoresceinated antibody and streptavidin, capture of the sandwich by filtration on biotinylated membrane, and labeling of the sandwich by anti-fluorescein urease conjugate. The concentration ratio of biotinylated to fluoresceinated antibodies was investigated and optimized. By the IFA/LAPS assay, the limit of detection (LOD) of VEE was approximately 30 ng/ml, similar to that achieved when chemically biotinylated monoclonal antibody (mAb) was applied. Total assay variance of the IFA/LAPS assay for both intra- and inter-assay precision was less than 20%. Assay accuracy was measured by comparing VEE concentrations estimated by IFA/LAPS standard curve to those obtained by conventional protein assay. VEE concentrations were found to differ by no more than 10%. The IFA/LAPS assay sensitivity was approximately equal to that of a conventional enzyme-linked immunosorbent assay (ELISA) utilizing polystyrene plates and a chromogenic substrate; however, less time and effort were required for performance of the IFA/LAPS assay. More importantly, use of genetically biotinylated scFv in the IFA/LAPS assay obviates the need for chemical biotinylation of antibody with resultant possible impairment of the antigen-binding site. Furthermore, the potential for batch-to-batch variability resulting from inequality in the number of biotin molecules labeled per antibody molecule is eliminated.     

Effects of short-duration transients on cardiac rhythm

Cardiac stimulation thresholds of short-duration large-amplitude electrical transients were studied. An isolated rabbit heart model was used and transients were applied directly to the heart through electrodes of 1 mm² and 1 cm² surface area. A variety of oscillatory waveforms and pulse configurations were studied and indicated that, for transients shorter than 100 μs, stimulation thresholds approach a constant charge-transfer density of 3·4 μC cm⁻².     

The cerebrocortical microcirculatory effect of nitric oxide synthase blockade is dependent upon baseline red blood cell flow in the rat

The effects of nitric oxide synthase (NOS) blockade on the cerebrocortical microcirculation were investigated under physiological conditions in anesthetized ventilated rats using laser-Doppler (LD) flowmetry. LD flow values of the parietal cortex were determined before and after systemic administration of the NOS inhibitor N(G)-nitro-L-arginine-methyl-esther. NOS blockade reduced the LD flow significantly and the magnitude of the reduction was in close correlation with the baseline value. Synchronized sinus-wave-like LD flow oscillations were observed frequently after NOS inhibition and their appearance was also dependent on the high baseline flow values. These results indicate marked, baseline-dependent differences in the cerebrocortical blood flow response to the inhibition of the nitric oxide pathway, and may suggest that areas with high resting red blood cell flow express high NOS activity.     

Psychotherapy for depression: current and future directions in research, theory, practice and public policy

This article is based on a symposium held at the 1998 Annual Meeting of Society for Psychotherapy Research (Snow Bird, Utah). Recognized experts addressed current and future directions in psychotherapy for depression from the perspectives of process and outcome research, basic research, theoretical models, clinical practice and training, and public policy. The specific issues discussed at the symposium included the strengths and limitations of major forms of psychotherapy; the therapeutic factors common and unique to different approaches; the future viability of current theories of depression; the role of treatment manuals in clinical practice and training; the development of new interventions based on basic research; and the priorities that should guide federal funding.     

肺癌细胞外基质的表达与临床病理的关系

目的探讨原发性肺癌层粘蛋白（Ｌａｍｉｎｉｎ,ＬＮ）、纤维连接蛋白（ｆｉｂｒｏｎｅｃｔｉｎ,ＦＮ）和Ⅳ型胶原的表达与临床病理的关系。方法采用免疫组化ＬＳＡＢ法检测１８４例肺癌标本中ＬＮ、ＦＮ和Ⅳ型胶原的表达。结果ＬＮ及Ⅳ型胶原在中、高分化的肺鳞癌中的表达均明显强于低分化组（Ｐ＜００１）,在有无淋巴结转移两组间的表达差异均具显著性（Ｐ＜００５）;肺鳞癌５年以上生存组ＬＮ、Ⅳ型胶原的表达明显高于０５年内死亡组（Ｐ＜００１）,ＦＮ的表达亦有差异（Ｐ＜００５）。肺腺癌的５年以上生存组中ＦＮ、Ⅳ型胶原的表达均强于０５年内死亡组（Ｐ＜００５,００１）。结论ＬＮ和Ⅳ型胶原的表达与肺鳞癌的组织学分级和淋巴结转移有关;ＬＮ、ＦＮ、Ⅳ型胶原的表达均可作为评估肺鳞癌预后的指标,而腺癌的预后仅与ＦＮ、Ⅳ型胶原的表达有关。