High accuracy pre-formed gradient discontinuous flow titrimetry.

A variant of Discontinuous Flow Analysis (DFA) titrimetry is described in which a pre-formed gradient is established between two titrant concentrations with the analyte aspirated at a constant rate into the gradient. The gradient encompasses a narrow range of analyte concentration (10% variation in this instance), and provides a high encoder pulse resolution. A simple acid-base titration model using photometric endpoint detection achieved comparable accuracy to conventional batch titrimetry (approximately 0.

Correlation between CD4+ counts and prevalence of cytomegalovirus retinitis and human immunodeficiency virus-related noninfectious retinal vasculopathy in patients with acquired immunodeficiency syndrome.

We prospectively studied 132 patients with acquired immunodeficiency syndrome (AIDS) to determine the cross-sectional prevalence of cytomegalovirus retinitis. All patients had serum CD4+ lymphocyte counts to determine the degree of immune dysfunction. Correlations between CD4+ counts, the presence of cytomegalovirus retinitis or human immunodeficiency virus (HIV)-related noninfectious retinal vasculopathy, and ocular symptoms were made.

An integrated approach to studying regulation of production of the antibiotic methylenomycin by Streptomyces coelicolor A3(2).

A physiological and molecular biological study was made of the control of methylenomycin biosynthesis by Streptomyces coelicolor A3(2). A simple and reliable assay for this antibiotic was developed. Conditions that permit the synthesis of methylenomycin by S.

A videofluoroscopy chair for the evaluation of dysphagia in patients with severe neuromotor disease.

Due to the difficulties encountered in positioning severely neurologically impaired individuals for videofluoroscopic studies, the Rehab Tech Video FluoroChair was developed. The purpose of the chair is to provide the severely disabled patient with safe, stable postural support in an upright position for videofluoroscopic studies, with anterior-posterior, lateral, and rotational views easily performed. The chair features a removable headrest, a full back support, armrests, lateral truncal supports, and a patented base which is clamped to the footboard of the radiology table and allows for 200 degrees rotation of the patient.

Streptomyces griseus streptomycin phosphotransferase: expression of its gene in Escherichia coli and sequence homology with other antibiotic phosphotransferases and with eukaryotic protein kinases.

The aphD gene of Streptomyces griseus, encoding a streptomycin 6-phosphotransferase (SPH), was sub-cloned in the pBR322-based expression vector pRK9 (which contains the Serratia marcescens trp promoter) with selection for expression of streptomycin resistance in Escherichia coli. Two hybrid plasmids, pCKL631 and pCKL711, were isolated which conferred resistance. Both contained a approximately 2 kbp fragment already suspected to include aphD.

Potentiometric combination ion/carbon dioxide sensors for in vitro and in vivo blood measurements.

The development and analytical performance of a novel potentiometric combination ion/pCO2 sensor design for in vitro and in vivo measurements are reported. The design is based on incorporating an appropriate ionophore within the outer silicone gas permeable membranes of both conventional macro and new catheter-type pCO2 sensors. Simultaneous measurement of the potentials across the ion-selective/gas permeable membrane and the inner glass or polymer pH sensitive membrane provides the basis for continuous monitoring of both ionic and pCO2 levels with the same device.

Quantitation of T cell antigen-binding molecules (TABM) in the sera of nonimmunized, immunized, and desensitized mice.

Heterologous antibodies to non-MHC-restricted T cell antigen-binding molecules (TABM) were used in an ELISA to detect and quantitate TABM levels in the sera of nonimmune mice and in mice immunized and/or desensitized to methylated bovine serum albumin (MBSA). TABM were detected at low levels in sera from nonimmune and immune mice. Amounts of TABM rose 300-fold in MBSA-immune mice within 12 hr of a desensitizing injection of MBSA, and rapidly returned to pre-desensitization levels.

Gas-liquid chromatographic determination of S,S,S-tributyl phosphorotrithioate (DEF) in water and fish tissue.

Methods are described for determination of S,S,S-tributylphosphorotrithioate (DEF) at levels as low as 5 parts per billion in fish and 200 parts per trillion in water. Fish tissue extracts are subjected to gel permeation chromatography (GPC) and silica gel chromatography; water samples are extracted with dichloromethane. Analyses are carried out by gas chromatography in which either electron capture or thermionic specific detectors are used.

Mechanical ventilation of patients with late stage Duchenne muscular dystrophy: management in the home.

Death in the late stage of Duchenne muscular dystrophy is most frequently a consequence of respiratory failure. Since muscles of ventilation become weakened the bellows mechanism fails insidiously. Patients exhibit symptoms of ventilatory insufficiency, the first to be noticed are those associated with CO2 retention: dyspnea, nightmares, increased heart rate, and increased blood pressure.