Photolysis of a protecting group for the carboxyl function of neurotransmitters within 3 microseconds and with product quantum yield of 0.2.

The synthesis of a photosensitive blocking group for the carboxyl function of neurotransmitters, in this case glycine, is reported. The compound, 2-methoxy-5-nitrophenyl glycine ester (caged glycine), is photolyzed by a laser pulse at 308 or 337 nm within 3 microseconds and with a product quantum yield of 0.2.

Rotational and translational water diffusion in the hemoglobin hydration shell: dielectric and proton nuclear relaxation measurements.

The dynamic properties of water in the hydration shell of hemoglobin have been studied by means of dielectric permittivity measurements and nuclear magnetic resonance spectroscopy. The temperature behavior of the complex permittivity of hemoglobin solutions has been measured at 3.02, 3.

Evaluation of the automated 'Enzymen-Test Anti HIV-1 + 2' and 'Enzymen-Test Anti HIV-1/2 selective' for the combined detection and differentiation of anti-HIV-1 and anti-HIV-2 antibodies.

A new, modular automated ELISA (test 1) for HIV-1 and HIV-2 antibody detection and differentiation (Enzymun-Test Anti HIV-1 + 2; anti HIV 1/2 selective, Boehringer Mannheim) was compared with 3 alternative enzyme immunoassays (Abbott recombinant HIV-1/HIV-2 3rd generation EIA, Abbott (test 2); Enzygnost HIV 1 + 2, Behringwerke (test 3); and Wellcozyme HIV recombinant, Murex (test 4)) and Western blot (New LAV I Blot and New LAV II Blot; Diagnostics Pasteur). 380 serum samples from HIV-1 and HIV-2 seropositive patients at different stages of disease, high risk individuals, patients with conditions unrelated to AIDS and from healthy blood donors were used in this evaluation along with 6 seroconversion panels, 6 serum dilution series and 'tricky' sera (repeatedly positive results in ELISA, but negative or undeterminate in Western blot; n = 67). Using the Western blot as reference assay, the overall sensitivity of the four ELISAs was 100%.

Toward routine diagnosis of hepatitis B virus desoxyribonucleic acid.

Although a multitude of hepatitis B markers are available to discriminate different states of hepatitis B virus (HBV) infection, there remains a need to detect the HBV DNA itself. The HBV DNA test is the only test that can quantify the number of complete virions. As shown in this review, the diagnostic value of testing for HBV DNA depends on quantification, and there are situations in which in vitro amplification is necessary and others in which testing for HBV DNA without preamplification is best.

An acetylcholine receptor regulatory site in BC3H1 cells: characterized by laser-pulse photolysis in the microsecond-to-millisecond time region.

When a neurotransmitter binds to its specific receptor, the protein forms transmembrane channels through which ions flow, leading to changes in transmembrane voltage that trigger signal transmission between neurons. How do inhibitors affect this process? Interesting and extensive information comes from investigations of the acetylcholine receptor, the best known of these proteins. This receptor is inhibited by cationic inhibitors, including local anesthetics, and acetylcholine at high concentrations.

Determination of the chemical mechanism of neurotransmitter receptor-mediated reactions by rapid chemical kinetic techniques.

Rapid chemical reaction techniques play an important role in unraveling the mechanism of reactions mediated by soluble proteins, including enzymes involved in the regulation of intracellular processes and the biosynthesis of proteins and nucleic acids. Regulatory proteins change conformation rapidly and must, therefore, be studied in the microsecond-to-millisecond time region. Similar techniques for investigating reactions mediated by membrane-bound neurotransmitter receptors were not available, and the mechanisms of the reactions are poorly understood.

Guidelines vs practice in the delivery of diabetes nutrition care.

The American Dietetic Association and the American Diabetes Association have published recommendations for the nutrition care of people with diabetes. However, the frequency of this care is rarely documented. As part of a study of diabetes care and education practices, the Michigan Diabetes Research and Training Center collected extensive data from 440 randomly selected adults who receive diabetes care from community physicians.

Virological and serological aspects of hepatitis B and the delta agent.

The hepatitis B virus (HBV) belongs to a group of viruses termed hepadnaviruses. The 3.2 kb genome encodes for a variety of proteins involved in viral replication (p-gene), transactivation (x-gene), or encodes for structural proteins (c- and s-genes).

Sub-acute effects of interferon-alpha 2 on adrenocorticotrophic hormone, cortisol, growth hormone and prolactin in humans.

This study investigated the chronic effects of interferon-alpha 2 (IFN-alpha 2) on hormonal secretion in humans. Six patients suffering from chronic hepatitis B or C infection received SC doses of 3 million IU IFN-alpha 2 three times a week for 4 mo. Each patient was examined for hormone secretion four times: the day before initial IFN-alpha 2 administration (day 0), the day of the first injection (day 1), and 4 wk after start of IFN therapy on days 27 (without IFN administration) and 28 (with IFN administration).

Antiviral effect of prolonged intermittent lymphoblastoid alpha interferon treatment in chronic hepatitis B.

In a European multicentre study 40 patients with HBeAg positive chronic hepatitis B virus (HBV) infection were treated with 5 mega units of lymphoblastoid alpha-interferon daily according to the following regimen: a four week primer course, four weeks of rest and a second course lasting 16 to 30 weeks. After 52 weeks of follow up, a response (HBeAg seroconversion and HBV-DNA negativity) was observed in 22 patients (55%). HBsAg seroconversion occurred in five patients (12.

How fast does an acetylcholine receptor channel open? Laser-pulse photolysis of an inactive precursor of carbamoylcholine in the microsecond time region with BC3H1 cells.

The integrated function of the nervous system depends on specific and rapid transmission of signals between its constituent cells. The nicotinic acetylcholine receptor is the best known of a group of membrane-bound proteins responsible for such transmission; for this process to occur, a specific neurotransmitter, in this case acetylcholine, must bind to the receptor, which then forms transmembrane channels through which cations pass. The resulting change in transmembrane voltage determines whether or not a signal is transmitted.

Synthesis and photochemistry of photolabile N-glycine derivatives and effects of one on the glycine receptor.

Three photolabile precursors of glycine containing a photosensitive 2-nitrobenzyl moiety attached to the amino group have been synthesized. When exposed to ultraviolet radiation between 308 and 350 nm, the compounds photolyze to release glycine, an important inhibitory neurotransmitter in the central nervous system. The identification of glycine as a photolysis product was determined by two different methods: separation of the photolyzed sample by thin-layer chromatography followed by a reaction with ninhydrin, and recognition of derivatized glycine using the Waters pico-tag method in conjunction with high-performance liquid chromatography.

On the mechanism of the gamma-aminobutyric acid receptor in the mammalian (mouse) cerebral cortex. Chemical kinetic investigations with a 10-ms time resolution adapted to measurements of neuronal receptor function in single cells.

The gamma-aminobutyric acidA (GABA) receptor belongs to a superfamily of proteins involved in chemical reactions that regulate signal transmission between cells of the nervous system and is the target of some of the agents most frequently used in medicine to control disorders of the central nervous system. In contrast to the nicotinic acetylcholine receptor, which initiates signal transmission and is the best characterized member of the superfamily, the GABA receptor forms anion-specific transmembrane channels and inhibits signal transmission. The chemical kinetic experiments described here, in which fast chemical reaction techniques were used, indicate that both receptor proteins may operate by the same mechanism.

On the mechanism of a mammalian neuronal type nicotinic acetylcholine receptor investigated by a rapid chemical kinetic technique. Detection and characterization of a short-lived, previously unobserved, main receptor form in PC12 cells.

The mammalian nicotinic acetylcholine receptor in PC12 cells has many properties characteristic of the neuronal receptors involved in key chemical reactions that are responsible for signal transmission between cells of the nervous system. This report describes initial investigations of the mechanism of this receptor using a rapid chemical kinetic technique with a time resolution of 20 ms, which represents a 250-fold improvement over the best time resolution (5 s) employed in previous studies. Carbamoylcholine, a stable analogue of the neurotransmitter acetylcholine, was the activating ligand used, and the concentration of open transmembrane receptor-channels in PC12 cells was measured by recording whole-cell currents at pH 7.

Hepatitis B and C in heterosexual patients with various sexually transmitted diseases.

The seroprevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections were prospectively assessed in 356 heterosexuals with STDs (sexually transmitted diseases) and compared to a control group of 381 healthy first-time blood donors. Eighty-one of 356 STD patients were anti-HBC positive (22.8%) compared to 14/381 blood donors (3.

Presynaptic calcium transients evoked by paired-pulse stimulation in the hippocampal slice.

The fluorescent dye Calcium Green and optical recording techniques were used to record intracellular Ca2+ transients resulting from paired-pulse stimulation in stratum moleculare of area CA1 in guinea-pig hippocampal slices. Presumed presynaptic calcium transients were recorded while glutamatergic synaptic transmission was blocked by kynurenic acid. Peak responses to paired-pulses (10-160 ms interval) were higher than responses to single pulses of same stimulation strength (42-23% increase).

Influence of vaccination schedules and host factors on antibody response following hepatitis B vaccination.

In a prospective multicentre trial, the influence of schedule, compliance, age, sex and weight on the antibody response to hepatitis B vaccination was investigated. Comparison of the vaccination schedules 0, 1, 6 months (group 1; n = 143) and 0, 1, 2, 12 months (group 2; n = 141) was performed in months 3, 7 and 12. In addition, the antibody response was compared one month after the third and one and six months after the last vaccination.

Multicenter evaluation of the novel ABN Western blot (immunoblot) system in comparison with an enzyme-linked immunosorbent assay and a different Western blot.

A new, modular Western blot (immunoblot) system for human immunodeficiency virus (HIV) antibodies (ABN WesPage; Wellcome) was compared with enzyme immunoassays (Wellcome, Behringwerke, and Abbott) and with a U.S. Food and Drug Administration (FDA)-licensed Western blot (DuPont) in a multicenter study.

[Viral hepatitis as a traveler's disease].

At the present time, at least five different forms of viral hepatitis can be distinguished. The hepatitis A and E viruses are transmitted via a fecal-oral route, and are associated with poor hygiene. Hepatitis E is restricted to Central Africa, parts of Asia, and Central America.

An assessment of computer use, knowledge, and attitudes of diabetes educators.

A questionnaire to survey attitudes, use, and knowledge of computers was sent to 816 randomly selected members of AADE to determine the degree to which currently available computer resources are used in diabetes education and to investigate the need for future computing resources designed to support diabetes education. Analysis of the data showed that even diabetes educators who use computers infrequently have a generally favorable attitude toward them. Highest use of computers is in noneducational applications, mostly for word processing and record keeping.

Quantal analysis of long-term potentiation of "minimal" excitatory postsynaptic potentials in guinea pig hippocampal slices: binomial approach.

"Minimal" excitatory postsynaptic potentials (EPSPs) were recorded from 13 neurones in area CA1 of guinea pig hippocampal slices after double-pulse stimulation of stratum radiatum (str. rad.) and stratum oriens (str.