BIS monitoring to prevent awareness during general anesthesia.

Background: Unexpected awareness is a rare but well-described complication of general anesthesia that has received increased scientific and media attention in the past few years. Transformed electroencephalogram monitors, such as the Bispectral Index monitor, have been advocated as tools to prevent unexpected recall.

Methods: The authors conducted a power analysis to estimate how many patients would be needed in an appropriately powered study to demonstrate the Bispectral Index monitor reduces awareness, as well as a cost analysis to assess the cost of using the monitor for this purpose alone.

Prolonged sedation with propofol in the rat does not result in sleep deprivation.

Unlabelled: The use of propofol provides sedation without prolonging emergence in patients in the Intensive Care Unit. When prolonged, however, continuous sedation may overlap with naturally occurring sleep periods and potentially increase the risk of sleep deprivation. We modified an established rat model of sleep to determine whether prolonged, continuous sedation results in sleep deprivation.

Abatement of ammonia and hydrogen sulfide emissions from a swine lagoon using a polymer biocover.

The purpose of this research was to determine the efficiency of a polymer biocover for the abatement of H2S and NH3 emissions from an east-central Missouri swine lagoon with a total surface area of 7800 m2. The flux rate of NH3, H2S, and CH4 was monitored continuously from two adjacent, circular (d = 66 m) control and treatment plots using a nonintrusive, micrometeorological method during three independent sampling periods that ranged between 52 and 149 hr. Abatement rates were observed to undergo a temporal acclimation event in which NH3 abatement efficiency improved from 17 to 54% (p = < 0.

The relationship of sedation to deliberate self-extubation.

Study Objectives: To evaluate the relationship between sedative therapy and self-extubation in a large medical-surgical intensive care unit (ICU).

Design: Retrospective, case-controlled study.

Setting: Large teaching hospital.

Psychological influences on the timing of orthodontic treatment.

Debates about the "ideal" timing of orthodontic treatment have focused on issues of biologic development and readiness. In this article we examine psychologic issues that should be considered in the decision to initiate orthodontics in the younger child or to wait until adolescence or later. Psychologic development during the preadolescent and adolescent stages may influence the child's motive for, understanding of, and adherence to treatment regimens.

A new biological assay for measuring cyanide in blood.

Unlabelled: Clinical diagnosis of cyanide poisoning is complicated by the lack of an easy, convenient assay for cyanide concentration in blood. Therapy may be delayed with unconfirmed diagnosis because the conventional antidote to cyanide poisoning exposes patients to substantial risks. We developed a new spectrophotometric assay to measure cyanide by extraction into a sodium hydroxide trap, followed by the addition of exogenous methemoglobin as a colormetric indicator.

Indications for mechanical ventilation.

Indications for mechanical ventilation have evolved substantially since widespread use of ventilatory support began in the early 1960s. While the metabolic and blood-gas alterations that mandate institution of ventilatory support have remained unaltered, new noninvasive modes of ventilation have widened the therapeutic options available to patients in acute respiratory failure. An understanding of the effect of mechanical ventilation on other organ systems has clarified the role of mechanical ventilation in the treatment of conditions other than respiratory failure such as stroke or head injury.

Lamivudine is effective in suppressing hepatitis B virus DNA in Chinese hepatitis B surface antigen carriers: a placebo-controlled trial.

Lamivudine is a novel 2',3'-dideoxy cytosine analogue that has potent inhibitory effects on hepatitis B virus replication in vitro and in vivo. We performed a single-blind, placebo-controlled study to assess its effectiveness and safety in Chinese hepatitis B surface antigen (HBsAg) carriers. Forty-two Chinese HBsAg carriers were randomized to receive placebo (6 patients) or lamivudine orally in dosages of 25 mg, 100 mg, or 300 mg daily (12 patients for each dosage).

Patients requiring sedation.

Recent advances in the pharmacology of sedative drugs have expanded their use in the intensive care unit. Indications and endpoints for sedation, however, often are defined poorly and are difficult to assess. Nevertheless, the complications of sedative drug administration are real.

Plasma and urine enrichments following infusion of L-[1-13C]phenylalanine and L-[ring-2H5]phenylalanine in humans: evidence for an isotope effect in renal tubular reabsorption.

Amino acids labeled with 13C or deuterium are commonly used in studies of amino acid metabolism. Traditionally, amino acid flux has been estimated by measurement of isotopic enrichment in the plasma pool; however, urine sampling as a noninvasive means of determining isotope enrichment has been increasing. The isotope enrichments and fluxes estimated from plasma and urine sampling were compared when two phenylalanine tracers (L-[1-13C]phenylalanine and L-[ring-2H5]phenylalanine) were intravenously infused for 4 hours in seven healthy men.

Immune response to Schistosoma mansoni infections in inbred rats. VII. Resistance is contingent on OX-8(+)-regulated high affinity IL-2 receptor-bearing W3/25+ lymphocytes but not on IL-4-dependent cells.

These studies assess the roles of subpopulations of T lymphocytes in resistance to Schistosoma mansoni. CDF rats were depleted of the T cell subpopulation bearing the high affinity IL-2R by in vivo treatment with ART18+ mAb or of soluble IL-4 by treatment with 11B11 mAb. The development of parasites, the expression of resistance after sensitization, and the intensity of delayed type hypersensitivity (DTH), Ag-mediated blast transformation (AMBT), IgG2a, passive cutaneous anaphylaxis, and IgE-mediated antibody-dependent cell-mediated cytotoxicity responses against S.

Resistance in murine schistosomiasis is contingent on activated IL-2 receptor-bearing L3T4+ lymphocytes, negatively regulated by Lyt-2+ cells, and uninfluenced by the presence of IL-4.

These studies assess the roles of subpopulations of T lymphocytes in inducing and modulating resistance to Schistosoma mansoni. C57BL/6 mice were depleted in vivo of L3T4+, Lyt-1+, Lyt-2+, IL-2R+ cells, or IL-4 by administration of appropriate mAb. Resistance and various correlative parameters of the immune response were studied in normal, depleted, and congenitally athymic mice.

IL-4 is required to generate and sustain in vivo IgE responses.

Antibodies of the IgE isotype play a predominant role in immediate hypersensitivity reactions. IL-4, a T cell-derived lymphokine that stimulates increased Ia expression by resting B cells and increased IgG1 secretion by LPS-activated B cells in vitro, has also been shown to regulate in vitro and in vivo polyclonal IgE responses. We report that large quantities of a purified anti-IL-4 mAb inhibit primary in vivo polyclonal IgE responses by 99% in mice infected with Nippostrongylus brasiliensis or injected with anti-IgD antibodies, and totally inhibit secondary Ag-specific IgE responses to TNP-keyhole limpet hemocyanin without effect on either IgG1 or IgG2a responses to these stimuli.

Evidence for presence of proinsulin-immunoreactive glycoprotein(s) in fetal bovine pancreatic extracts.

A large-molecular-weight proinsulin-immunoreactive protein fraction was obtained from an extract of fetal bovine pancreases by gel filtration in 6 M guanidine-1 M acetic acid. Concanavalin A-Sepharose-affinity column chromatography of the large-molecular-weight fraction yielded a discrete alpha-methyl-mannoside-displaceable immunoreactive peak that also displayed N-acetylglucosamine-specific binding to wheat germ lectin-Sepharose. Chemically tritiated and radioiodinated lectin-reactive proteins interacted specifically with antibodies to insulin and bovine proinsulin.

In vivo and in vitro inhibition of human histidine decarboxylase by (S)-alpha-fluoromethylhistidine.

Histidine decarboxylase (HDC) activity in Ficoll-Hypaque purified human peripheral blood leukocytes (PBL) was determined by measuring the formation of [3H]histamine from L-[3H]histidine. HDC activity was inhibited in vitro to more than 90% by (S)-alpha-fluoromethylhistidine (alpha-FMH) at concentrations of 10(-5) M and above. Both polymorphonuclear and mononuclear cells possessed HDC activity, but on a per cell basis the former had several-fold higher enzyme activity than the latter.

Characterization of a chemically tritiated large molecular weight glucagon immunoreactive protein species by lectin-affinity column chromatography and reaction with anti-glucagon antibodies.

High molecular weight glucagon immunoreactive material, obtained by gel-filtration (in the presence of 6 M guanidine hydrochloride) of fetal bovine pancreatic extracts, was tritiated by reductive methylation. Concanavalin-A-Sepharose column chromatography of the radiolabeled preparation yielded a discrete Concanavalin-A-reactive, alpha-methyl-mannoside-displaceable radioactive peak, coinciding with the glucagon immunoreactive peak. Submission of the Con-A-reactive material to wheat germ agglutinin-Sepharose column chromatography yielded a lectin-reactive, N-acetyl-glucosamine-displaceable radioactive peak, coinciding with the glucagon immunoreactive peak.

Beta-endorphin-like immunoreactivity in extracts of the fetal bovine pancreas. Column chromatographic characterizations of a high-molecular-weight immunoreactive species.

Acid-ethanol extracts of fetal bovine pancrease were examined for the presence of beta-endorphin-like immunoreactivity. Gel-filtration analyses revealed the presence of a major large-molecular-weight beta-endorphin immunoreactive species of approximately 20K delta. This molecular form maintained its size upon resubmission to gel filtration in the presence of 6 M guanidine hydrochloride, separated from the bulk of the glucagon immunoreactivity upon ion-exchange chromatography, showed proportional dilution in the beta-endorphin radioimmunoassay, and interacted in a biospecific manner with Concanavalin-A-Sepharose.

A monoclonal antibody (100C5) to the Lyt-2-T cell population expanding in MRL/Mp-lpr/lpr mice detects a surface antigen normally expressed on Lyt-2+ cells and B cells.

MRL/Mp-lpr/lpr (MRL-lpr) mice develop a generalized lymphadenopathy reflecting the expansion of a Lyt-2- T cell population. The present report describes the pattern of reactivity of a xenogeneic monoclonal antibody (mAb 100C5) directed against this T cell population. By single- and two-color flow cytofluorometry analysis this mAb was found to stain brightly 80-90% of T cells in enlarged MRL-lpr lymph nodes.

Glycoprotein-like large glucagon immunoreactive species in extracts of the fetal bovine pancreas.

Large glucagon immunoreactive substances, extracted from the fetal bovine pancreas and separated by gel filtration in the presence of 6 M guanidinium-hydrochloride, were submitted to lectin-sepharose affinity column chromatograph. Gel-filtered peak I (approximately 45 K delta) and peak II (approximately 10 K delta) interacted biospecifically with concanavalin-A- and wheat-germ-lectin-sepharoses, suggesting glycoproteins as possible constituents of large glucagon immunoreactive substances in extracts of the fetal bovine pancreas. The glucagon-like immunochemical identity of the lectin-sepharose-bound substances was further substantiated by binding to antiglucagon antibodies-sepharose and by characteristic proportional dilutions in the glucagon radioimmunoassay.