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B Hanson

Publications and source records attributed to B Hanson.

At least 37 records · Page 2Linked to original sources
PubMed1997

Evaluation of a dipstick enzyme-linked immunosorbent assay for detection of antibodies to dengue virus.

Accurate serological confirmation of dengue (DEN) infection is difficult, because simple reliable assays for the detection of DEN antibodies are not available. To address this problem, a dipstick enzyme-linked immunosorbent assay (ELISA) was evaluated. The dipstick contained dots of serially diluted DEN 2 antigen. To detect immunoglobulin G (IgG), the dipstick was processed through four reaction cuvettes containing test serum, enhancer, enzyme-conjugated anti-human IgG and IgM antibody, and substrate. Total assay time was 45 min. To detect IgM, the serum was passed through a protein G device to remove IgG. The dipstick was then processed as before, except that the incubation times were longer and enzyme-conjugated anti-human IgM was used. The total assay time was 3 h. The dipstick ELISA results were compared with results from microplate ELISA. The IgG dipstick ELISA showed a sensitivity of 95.2% and a specificity of 100% compared to an IgG microplate ELISA with serum samples from 125 individuals living in an area in which DEN is endemic. In tests with 75 serum samples from patients with clinically suspected acute DEN infections, the IgM dipstick ELISA showed a sensitivity of 97.9% and specificity of 100% compared to those of an IgM antibody capture microplate ELISA. These results showed that the dipstick ELISA was a sensitive and specific test for the detection of either DEN IgM or IgG in human serum. The dipstick ELISA was also shown to be useful for detecting seroconversions to DEN IgM or IgG in paired serum samples from 20 patients with virus isolation-confirmed acute DEN infections.

Animals↗
PubMed1996

A receptor for the import of proteins into human mitochondria.

We have characterised a 16.3-kDa human protein that functions as a receptor for the import of preproteins into mitochondria. Based on amino acid sequence alignments, the protein (hMas20p) is 41% similar to Mas20p (20-kDa mitochondrial assembly protein) from yeast Saccharomyces cerevisiae and 38% similar to MOM19 (19-kDa mitochondrial outer-membrane protein) from Neurospora crassa. hMas20p has a putative N-terminal transmembrane sequence of 29 amino acids and an acidic C-terminus. A 13-kDa fragment [des-(1-29)-hMas20p], which lacks the 29-amino acid putative N-terminal transmembrane domain, is soluble when expressed in Escherichia coli. Antibodies produced against this domain crossreacted with a protein of 16 kDa in outer membranes of mitochondria from rat liver and inhibited import of protein into isolated mitochondria from rat liver. In addition, the recombinant soluble domain folds into a functional structure as it competes with hMas20p on the mitochondrial surface for precursor binding, confirming the functional role of hMas20p in the import of preproteins into mitochondria.

Amino Acid Sequence↗
PubMed1995

Phosphaturia, glycosuria and aminoaciduria associated with idiopathic acquired sideroblastic anemia.

Idiopathic acquired sideroblastic anemia is not a common disease. We studied the renal tubular function in such patients. Patients have lower calcium than controls (8.46 mg/dl +/- 0.59 vs 9.16 +/- 0.53). We have highlighted the multiple renal anomalies observed in patients with this type of hemopathy. The serum phosphate levels are lower in patients than in controls (2.73 +/- 0.36 vs 3.3 +/- 0.55 mg/dl, p = 0.0048). We found higher glycosuria (21:43 +/- 42.58 vs 0.0 +/- 0.0 mg/dl), total aminoaciduria (6280 +/- 3943 vs 4138 +/- 2269 microMol/g creatinine, p = 0.19) and lower maximum capacity for phosphate reabsorption by the renal tube (TmPO4) (2.11 +/- 0.38 vs 2.9 +/- 0.73 mg/100 ml GFR, p = 0.0027) in the patients. The association between idiopathic acquired sideroblastic anemia and the multiple tubular anomalies corresponding to the syndrome initially described by Fanconi has not been reported to date. The underlying mechanism is not understood, but, taken separately, these two anomalies commonly present heme metabolic anomalies in the mitochondria. We hypothesize that this syndrome could represent the clinical expression of a mitochondrial cytopathology.

Aged↗
PubMed1994

Sensory perception of patients on selected antineoplastic chemotherapy protocols.

Antineoplastic chemotherapy (ANCT) is a primary and adjuvant treatment modality for cancer. Although researchers have found that patients who are given preparatory sensory information before various health-care procedures experience less discomfort, literature describing subject's sensory experience before, during, and after ANCT is lacking. The purpose of this study was to elicit sensory responses from subjects before, during, and after one of six cycles of their initial course of treatment on one of two emetogenic ANCT protocols. These descriptions will be used to develop a preparatory sensory nursing intervention that may promote self-care and help cancer patients cope with the distress of chemotherapy. The Sensory Information Questionnaire was administered to a sample of 44 subjects who had just completed a cycle of ANCT. Subjects provided descriptors of all senses. The senses for which subjects most frequently provided descriptors were taste, touch, and smell. Descriptors varied for some sensations according to the chemotherapy drug protocols.

Adaptation, Psychological↗
PubMed1992

Growth characteristics and proteins of plaque-purified strains of Rickettsia tsutsugamushi.

Six plaque-purified strains of Rickettsia tsutsugamushi (Karp, Gilliam, Kato, JC472B, TA716, and TA763) that fall into three categories of virulence for mice were compared by several parameters. Five of the six strains formed plaques of identical size in mouse cells, but each of three strains tested (representing three mouse virulence types) had a different doubling time in mouse cell cultures. Neither of these properties correlated strictly with virulence in mice, although the avirulent TA716 strain replicated much more slowly than the more virulent Karp and Gilliam strains. R. tsutsugamushi strain heterogeneity was also manifested at the polypeptide level by migration rates in sodium dodecyl sulfate-polyacrylamide gels of three of the major scrub typhus antigens (Sta110, Sta56, and Sta47), with those of Sta110 differing most widely. As expected, immunoblotting with polyclonal mouse sera showed substantial cross-reactivity among the major antigens of the six strains. Similar tests with Karp-induced monoclonal antibodies (MAb) demonstrated that some epitopes on Sta110 and Sta56 were shared by fewer than the six strains, but they identified no epitope unique to Karp. In contrast to the ready demonstration of antigenic heterogeneity in Sta110 and Sta56, four of the five Sta47-specific MAb reacted well with Sta47 from each of the six strains; the remaining MAb bound Sta47 from Karp and the Karp-like JC472B strain more strongly than Sta47 from the other four strains. The MAb also were useful in indicating the possible occurrence of Sta47 as dimers and trimers, the presence of Sta110 (as well as Sta56 and Sta47) in the rickettsial membrane, and the apparent interaction of the putative heat shock protein Sta58 with Sta47 or Sta47-Sta56 complexes.

Animals↗
PubMed1991

Inhibition of burn pain by intravenous lignocaine infusion.

Patients with burns often suffer severe pain, especially during dressing of wounds, but there are no established alternatives to potent opiate analgesics, with their various side-effects. Intravenous lignocaine infusion strikingly reduced self-assessed pain scores in 7 patients during the first 3 days after second-degree burns, without need for supplementary opiate analgesia.

Burns↗
PubMed1991

Susceptibility of Rickettsia tsutsugamushi Gilliam to gamma interferon in cultured mouse cells.

Recombinant rodent gamma interferon (IFN-gamma) inhibited the infection of cultured BALB/3T3 mouse fibroblasts by Rickettsia tsutsugamushi Gilliam, apparently mainly by clearance of intracellular rickettsiae. No significant effect on rickettsial entry into the cells was noted; IFN-gamma was toxic to infected cells, as measured by the capacity of treated, infected cells to attach to the surfaces of culture vessels. In a small proportion of IFN-gamma-treated cells, rickettsial replication appeared to persist at normal levels. A fraction (28%) of rickettsiae clonally isolated from cultures treated with IFN-gamma was resistant to IFN-gamma-mediated inhibition, but four serial passages of these resistant clones in the absence of additional IFN-gamma resulted in the loss of resistance. In several respects, therefore, the IFN-gamma-mediated inhibition of scrub typhus rickettsiae in cultured fibroblasts was similar to that reported for Rickettsia prowazekii.

3T3 Cells↗
PubMed1991

Comparative susceptibility to mouse interferons of Rickettsia tsutsugamushi strains with different virulence in mice and of Rickettsia rickettsii.

Three strains of Rickettsia tsutsugamushi (Karp, Gilliam, and TA716, representing three virulence types in mice) were examined for their sensitivity to the inhibitory effects of recombinant gamma interferon (IFN-gamma) and purified IFN-alpha/beta in two cultured mouse fibroblast cell lines. The susceptibilities of another species, Rickettsia rickettsii, and of encephalomyocarditis virus (EMCV) were also tested for comparative purposes. IFN-gamma inhibited rickettsial replication in only one of the six combinations of R. tsutsugamushi strains and mouse cells (strain Gilliam and the BALB/c mouse-derived cell line). In contrast, R. rickettsii and EMCV replication were markedly inhibited in both cell types, but to a greater extent in the BALB/c line than in the C3H cells. IFN-alpha/beta (300 to 450 U/ml) was uniformly ineffective in three of the combinations of R. tsutsugamushi strains and mouse cells (Gilliam in C3H cells and Karp in both C3H and BALB/c cells); in the remaining sets, IFN-alpha/beta-mediated inhibition of rickettsial replication was variable and in no case was it very pronounced. The tests with R. rickettsii in both cell types also indicated slight, variable sensitivity to IFN-alpha/beta. EMCV, on the other hand, was very susceptible to IFN-alpha/beta, confirming the potency of the preparation used; as with IFN-gamma, virus replication was inhibited to a greater degree in the BALB/c cell line than in the C3H cultures. These results are discussed in terms of their relationship to the virulence properties of the R. tsutsugamushi strains in BALB/c and C3H mice and to the known IFN-sensitivities of the more widely studied Rickettsia prowazekii.

3T3 Cells↗
PubMed1991

Atopic disease and immunoglobulin E in twins reared apart and together.

Both genetic and environmental influences have been implicated in the etiology of atopic disease and in the determination of serum IgE levels. To quantify the relative contribution of these influences, we studied the prevalence of asthma and seasonal rhinitis, skin-test response, total serum IgE levels, and specific IgE, as measured by RAST, in a sample of MZ and DZ twins reared apart or together. Concordance rates for asthma, rhinitis, positive skin tests, and RAST were calculated. MZ twins, whether reared apart or together, showed a greater concordance than dizygotic twins reared apart or together. Maximum-likelihood tests of genetic and environmental components of the variation of total IgE levels revealed a substantial genetic component and a negligible contribution from common familial environmental effects.

Asthma↗
PubMed1989

Genetic factors in the electrocardiogram and heart rate of twins reared apart and together.

Important physiologic mechanisms have been thought not to exhibit large amounts of variability, due in part to the assumption that critical biologic functions will have evolved to an evolutionary optimum. The attainment of this optimum would necessarily eliminate individual differences in these variables. Using a sample of monozygotic and dizygotic twins reared apart since birth or early infancy, 12-lead electrocardiographic recordings and vectorcardiograms were obtained. Values of these variables for monozygotic and dizygotic twins reared together were obtained from other studies. Maximum likelihood tests of genetic and environmental components of variation for PR interval, QRS duration, QT interval and ventricular rate indicated a significant contribution of genetic effects (most heritabilities ranged from 30 to 60%), with a negligible contribution from common familial environmental effects.

Electrocardiography↗
PubMed1989

Effectiveness of sodium fluoride on tooth hypersensitivity with and without iontophoresis.

The purpose of this study was to assess the short and long term reduction of dentinal hypersensitivity by a single application of sodium fluoride with and without iontophoresis. Two teeth in each of 16 patients were blindly evaluated before and after treatment, and at 1, 3, and 6 months. A blast of air and tactile pressure were used to assess pain. Results indicate that there is significant, immediate reduction in dentinal hypersensitivity with the use of iontophoresis that is lost with time. The use of sodium fluoride alone had no effect. Sodium fluoride with iontophoresis was demonstrated to have an immediate post treatment effect (P less than .001) that lasted through the 3-month observation period. The data suggest that iontophoresis may be a useful adjunct to sensitivity therapy and that an immediate therapeutic effect may be achieved. The efficacy of the use of sodium fluoride alone is obscured by the natural reduction of root sensitivity observed with time.

Dentin Sensitivity↗
PubMed1987

Factors influencing Rickettsia tsutsugamushi infection of cultured cells.

Several factors which influence Rickettsia tsutsugamushi infectivity of, and replication in, cultured cells have been investigated in order to establish standard laboratory conditions for reliable quantitation and maximization of rickettsial yield and to begin to explore the nature of the relationship between the rickettsia and its host cell. The extent of scrub typhus rickettsial association with host cells was dependent on the rickettsial and target cell concentrations and on the medium in which the infection took place. Brain heart infusion broth, a standard rickettsial diluent for infectivity, was markedly inhibitory. Both rickettsial and host cell replication were dependent on a component(s) supplied by serum to the tissue culture medium; rickettsial multiplication was less affected by small temperature variation (optimum 34 to 37 degrees C) than was host cell growth (optimum 37 degrees C). The antibiotic daunomycin was very useful in selectively inhibiting host cell replication and permitting attainment of somewhat greater rickettsial yields than in uninhibited cells. These findings have underscored the close relationship between parasite and infected cell and have led to more predictable, higher yields of rickettsiae in vitro.

Animals↗
PubMed1987

Improved plaque assay for Rickettsia tsutsugamushi.

The assay of Rickettsia tsutsugamushi infectivity by plaquing has been improved substantially by a number of changes which were based on our understanding of factors which enhance scrub typhus rickettsial infection of, and replication in, cultured cells. Greater numbers of plaques and/or larger plaques resulted from: use of tissue culture medium instead of brain heart infusion broth as the rickettsial diluent; plaquing in a contact-inhibited mouse embryo cell line rather than in growth-inhibited or uninhibited Vero cells; infection and incubation of monolayers at 35 degrees C instead of at lower temperatures; frequent feeding of infected cultures with medium containing ample amounts of serum; and inclusion of chicken serum in the overlay medium. Plaquing in 24-well tissue culture plates instead of in petri dishes or flasks greatly simplified the handling of large numbers of samples and was beneficial economically as well. Easily recognized rickettsial plaques were counted microscopically under x40 magnification, and maximum counts were obtained 12-14 days after infection, depending on the rickettsial strain. Slightly longer incubation yielded macroscopically visible counts. In addition to enhancing plaque number and size, the changes in standard R. tsutsugamushi plaquing methods resulted in an easier, faster, and more reliable assay, with improved reproducibility of plaque formation, maintenance of infected cell monolayers, and avoidance of microbial contamination.

Animals↗