Determination of meningococcal antibodies by microassay. (65/8252)

A modified microassay procedure, using triphenyltetrazolium chloride as a germination indicator, was compared with a macroassay method proposed by the World Health Organization for determining the level of antibodies before and after immunization with Group A meningococcal polysaccharide vaccine. There was excellent agreement between the results obtained by the two methods. The vaccine used appeared to be safe and immunogenic.  (+info)

MORLUC numeric system for the identification of Enterobacteriaceae. (66/8252)

Foul hundred eighty-six members of the Enterobacteriaceae representing nine genera were identified by conventional methods, and the results were compared with MORLUC (Biotrol Company Inc., Jamaica, N.Y.). MORLUC, an acronym for melibiose, ONPG (o-nitrophenyl-beta-galactopyranoside), rhamnose, lysine decarboxylase, urease, and citrate, are six prepackaged reagent-impregnated paper loops which are sealed within a plastic packet. The hydrogen sulfide reaction obtained from a triple sugar iron slant is coupled with MORLUC results and is readily converted into a three-digit numerical code, which is referenced on a preprinted single page listing. Additionally, the triple sugar iron is used to confirm the glucose fermentation by an unknown isolate. Comparisons of individual MORLUC tests and standard methods results in a better than 92% agreement, except for unrease. Four hundred sixty-six of the 486 bacterial isolates, or 96% of the strains which were numerically identified by MORLUC, agreed with conventional diagnoses.  (+info)

Coil occlusion of aortopulmonary collateral arteries in an infant with scimitar syndrome. (67/8252)

Scimitar syndrome in infancy is a rare condition, presenting with severe congestive heart failure and pulmonary hypertension. The presence of large systemic-pulmonary collateral arteries may play a role in the cause of heart failure and pulmonary hypertension. A 4-month-old infant underwent coil occlusion of large anomalous systemic arteries supplying the right lower pulmonary lobe. Symptoms of severe congestive heart failure and pulmonary hypertension improved dramatically with coil occlusion, and surgical correction was performed 3 months later without any complications. Coil occlusion of anomalous systemic arteries can improve symptoms of heart failure and pulmonary hypertension in infants and may bring about a good surgical result for this disease.  (+info)

Pharmacokinetics and absolute bioavailability of ribavirin in healthy volunteers as determined by stable-isotope methodology. (68/8252)

Ribavirin has recently been demonstrated to have efficacy in combination with alpha interferon for treatment of relapsed hepatitis C. The marked improvement in the response rate after treatment with the combination regimen (10-fold higher versus that from monotherapy with alpha interferon) highlights the importance of determining the absolute bioavailability of ribavirin as a first step in beginning to investigate the pharmacodynamics of the combination. The objective of this study was to determine the absolute bioavailability of ribavirin with an intravenous formulation containing ribavirin labeled with the stable isotope (13)C(3) ((13)C(3)-ribavirin) and unlabeled oral ribavirin. Six healthy volunteers received 150 mg of intravenous (13)C(3)-ribavirin followed 1 h later by a 400-mg oral dose of ribavirin. Samples of blood and urine were collected up to 169 h postdosing. Concentrations of (13)C(3)-ribavirin and unlabeled ribavirin were determined by a high-performance liquid chromatography tandem mass spectrometric method. All plasma and urine data were comodeled for labeled and unlabeled ribavirin by using both the two- and three-compartment models in the program ADAPT II. A three-compartment model was chosen for the pharmacokinetic analysis with the Akaike Information Criterion. The mean maximum concentrations of drug in plasma for intravenous and oral ribavirin were 4,187 and 638 ng/ml, respectively. The mean bioavailability was 51.8% +/- 21.8%, and the mean gamma-phase half-life was 37.0 +/- 14. 2 h. The mean renal clearance, metabolic clearance, and volume of distribution of the central compartment were 6.94 liters/h, 18.1 liters/h, and 17.8 liters, respectively. The use of the stable-isotope methodology has provided the best estimate of the absolute bioavailability of ribavirin that is currently available, as there was neither a period bias nor a washout effect to confound the data. The study demonstrated that the mean bioavailability for a 400-mg dose of ribavirin was 52%, which is higher than that previously reported in other investigations.  (+info)

A re-evaluation of the molecular mass of earthworm extracellular hemoglobin from meniscus depletion sedimentation equilibrium. Nature of the 10 S dissociation species. (69/8252)

Previous calculations from meniscus depletion sedimentation equilibrium earthworm hemoglobin from Lumbricus terrestris (E.J. Wood et al., Biochem. J. 153 (1976) 589-96) and from the related species Lumbricus sp. (L. sp.) (M.M. David and E. D Mol. Biol. 87 (1974) 89--101) were made on the assumption that the solutions behaved ideally. Re-examination of their results reveals, however, a dependence of the apparent molecular mass on concentration. Taking this effect into consideration, we have nowrecalculated from their data molecular masses of 4.4--4.5 MDa for the hemoglobin of both L. terrestris and L. sp. On the basis of the new determinations, we propose for the polypeptide chain composition of L. terrestris hemoglobin a model [(abcd )4L1L2L3]12 where a,b,c,d are the four globin and L1,L2,L3 are the three major linker chain constituents of the protein. The model is consistent with the D6 symmetry of the molecule. A 10 S intermediate product in the alkaline dissociation Lumbricus hemoglobin is viewed as a binary mixture of products resulting from a disproportionation reaction involving the structural unit. The present interpretation is shown to be consistent with observed relations between molecular masses and SDS gel electrophoretic band patterns of 10 S species and intact hemoglobin.  (+info)

Measurement of limb venous compliance in humans: technical considerations and physiological findings. (70/8252)

We conducted a series of studies to develop and test a rapid, noninvasive method to measure limb venous compliance in humans. First, we measured forearm volume (mercury-in-Silastic strain gauges) and antecubital intravenous pressure during inflation of a venous collecting cuff around the upper arm. Intravenous pressure fit the regression line, -0.3 +/- 0.7 + 0.95 +/- 0.02. cuff pressure (r = 0.99 +/- 0.00), indicating cuff pressure is a good index of intravenous pressure. In subsequent studies, we measured forearm and calf venous compliance by inflating the venous collecting cuff to 60 mmHg for 4 min, then decreasing cuff pressure at 1 mmHg/s (over 1 min) to 0 mmHg, using cuff pressure as an estimate of venous pressure. This method produced pressure-volume curves fitting the quadratic regression (Deltalimb volume) = beta(0) + beta(1). (cuff pressure) + beta(2). (cuff pressure)(2), where Delta is change. Curves generated with this method were reproducible from day to day (coefficient of variation: 4.9%). In 11 subjects we measured venous compliance via this method under two conditions: with and without (in random order) superimposed sympathetic activation (ischemic handgrip exercise to fatigue followed by postexercise ischemia). Calf and forearm compliance did not differ between control and sympathetic activation (P > 0.05); however, the data suggest that unstressed volume was reduced by the maneuver. These studies demonstrate that venous pressure-volume curves can be generated both rapidly and noninvasively with this technique. Furthermore, the results suggest that although whole-limb venous compliance is under negligible sympathetic control in humans, unstressed volume can be affected by the sympathetic nervous system.  (+info)

Construction of a double-stranded deoxyribonucleotide sequence of 45 base pairs designed to code for S-peptide 2-14 of bovine ribonuclease A. (71/8252)

An artificial DNA duplex, each strand consisting of 45 monomers, is constructed from chemically synthesized deoxyribooligonucleotides. The resulting bihelical polymer may code for a modified S-peptide of Ribonuclease A. This is the first synthetic duplex designed to code for a eukaryotic message.  (+info)

A new method of DNA denaturation mapping. (72/8252)

Described is a new method for DNA denaturation mapping utilizing glyoxal (ethanedial) to stabilize the denatured regions. The extent of glyoxal reaction can be easily and sensitively measured using an assay based on the intercalation of ethidium into duplex DNA. Thus denturation maps can be produced in a controlled way under a wide variety of conditions.  (+info)