Search PubMed⌕ Search

Biomedical subjects

H G Muchmore

Publications and source records attributed to H G Muchmore.

At least 37 records · Page 2Linked to original sources
PubMed1981

Persistent parainfluenza virus shedding during isolation at the South Pole.

Persistent parainfluenza virus shedding in healthy young adults occurred throughout the 8 1/2-month winter isolation period at Amundsen-Scott South Pole Station during 1978. Two episodes of respiratory illness were observed after 10 and 29 weeks of complete social isolation. Throat swabs collected both routinely, and during each outbreak of respiratory illness, were directly inoculated into cell cultures. Parainfluenza virus types 1 and 3 were recovered from both symptomatic and asymptomatic subjects throughout the winter. No other viruses were obtained by these efforts. The presence of parainfluenza virus in these subjects long after the accepted incubation period for viral upper respiratory illness, and when the introduction of new virus to this community was impossible, suggests its persistence in man.

Animals↗
PubMed1981

Immunologic reactions of rabbit anti-Mycoplasma arthritidis serum with in vitro cultivated rat synovial cells.

The pathogenesis of the intra-articular, arthritic-inflammatory reaction caused by Mycoplasma arthritidis in susceptible rats and mice is poorly understood. To investigate this problem, synovial cells from normal Sprague-Dawley rats were cultured and studied in vitro. These cells continued to produce hyaluronic acid as measured by viscosity and chemical assays. Normal synovial cells were treated with rabbit serum specimens taken before and after immunization with M. arthritidis. Cytotoxicity assays indicated that the cells were killed in the presence of rabbit anti-M. arthritidis serum but not with preimmunization serum specimens. The anti-M. arthritidis serum was not cytotoxic to monolayer cultures of HEp-2, Vero, or L-cells. Antiserum produced in response to M. fermentans, M. hominis, and M. pulmonis did not produce a cytotoxic effect on the cultured synovial cells. From immunofluorescence studies it was demonstrated that the interactions occurred between the rabbit anti-M. arthritidis serum and synovial cell surface antigens. Extreme precautions were taken to prevent mycoplasmal contamination of rats and the synovial cells in culture. These observations would appear to support previous reports implicating mycoplasmas as biological triggering mechanisms of autoimmune reactions.

Animals↗
PubMed1981

Enzyme-linked immunosorbent assays in murine cryptococcosis.

In this investigation, enzyme-linked immunosorbent assay (ElISA) procedures were used to study the time of appearance and the duration of demonstrable antigen and antibody in body fluids of mice with disseminated cryptococcosis. The ELISA antigen procedure detected cryptococcal capsular polysaccharide (CCP) in the serum and urine of infected mice 3 days after infection--4 days before it could be demonstrated by the latex agglutination procedure. ELISA-reactive antibody was present throughout the course of infection (mean death time, 32 days), whereas antibody was not detected by whole cell agglutination after day 20. High serum concentrations of CCP (titers to 64,000) persisted throughout the course of infection, while antibody declined to low levels with progression of disease. ELISA provides a sensitive system for quantitation and monitoring of antigen (CCP) processing and clearance (or storage), and for cryptococcal antibody formation in progressive cryptococcosis.

Agglutination Tests↗
PubMed1980

Development of an enzyme immunoassay for cryptococcal antibody.

An enzyme immunoassay (ELISA) for measurement of cryptococcal IgG antibody in human serum is described. Clinical studies indicate that the assay is a useful addition to the currently available techniques for measuring antibodies in cryptococcosis. IgG-specific antibody (titers 4 to 1,024) was detected in the serum of 78% of the cryptococcosis patients tested and in 61% of the serum from healthy individuals with positive delayed skin hypersensitivity to cryptococcin. The micro-ELISA for cryptococcal antibody is of potential value in patient management, and in epidemiological studies.

Animals↗
PubMed1980

Comparison of enzyme immunoassay and latex agglutination methods for detection of Cryptococcus neoformans antigen.

An enzyme immunoassay for the measurement of cryptococcal capsular polysaccharide in human body fluids is described. The enzyme immunoassay detects cryptococcal capsular polysaccharide at a concentration of 6 ng/ml, compared with 35 ng/ml detectable by the latex agglutination test. The enzyme immunoassay detects cryptococcal capsular polysaccharide in body-fluid specimens that are negative by the latex agglutination test. Titers by enzyme immunoassay are generally higher and persist longer into the treatment period than those determined by latex agglutination. No cryptococcal capsular polysaccharide is detected by the enzyme immunoassay procedure in fluids from subjects not known to have cryptococcosis. The enzyme immunoassay procedure presented here provides earlier detection of cryptococcal material in body fluids, and thereby diagnosis and treatment of cryptococcosis can be made earlier in the course of disease.

Antigens, Fungal↗
PubMed1980

Cryptococcus neoformans serotype groups encountered in Oklahoma.

Eighty clinical and 28 soil isolates of C. neoformans obtained in Oklahoma were separated into A-D and B-C serotype groups utilizing creatinine-dextrose agar with bromthymol blue. Previously, serotype B-C clinical isolates have been frequent only in patients from Southern California where as many as 50% of the isolates are of this type. In contrast, in patients from the rest of the United States the B-C frequency has been only 6%. Of the 80 C. neoformans isolates from Oklahoma patients, 12 (15%) were serotype B-C. One-half of these 12 Oklahoma patients with serotype B-C isolates had no history of any travel to California, and were long-time residents of Oklahoma. All 28 soil isolates of C. neformans from Oklahoma in this study were serotype A-D. Since serotype B-C recovery from a soil sample has never been reported, attempts are in progress to isolate serotype B-C from the environments of these patients from Oklahoma.

Adult↗
PubMed1980

Serologic evidence for parainfluenzavirus infection during isolation at South Pole Station, Antarctica.

Two distinct mid-winter outbreaks of respiratory tract illness (RTI) occurred among South Pole Station personnel during the winterover period of 1976. One outbreak began early in May eight weeks after total isolation began, the second occurred in August and September after 20 weeks of complete social isolation. Sequential sera collected from 16 of the 18 subjects wintering at South Pole during 1976 were tested by hemagglutination inhibition for antibody against parainfluenzavirus types 1 and 3. Serologic responses were detected against parainfluenzavirus 1 and 3 antigens during the outbreak that occurred in May, and one subject showed a response to parainfluenzavirus 1 in September. Serologic responses occurred in both symptomatic and asymptomatic subjects and were chronologically compatible with the observed illnesses. Throat swabs collected both routinely during the winter and during each outbreak of illness and maintained at -70 C failed to reveal the causative agent when inoculated into cell culture at the home laboratory the following year. Outbreaks of mid-winter RTI and serologic responses in adult subjects isolated at South Pole Station suggest persistence of parainfluenzavirus in the human adult. Confirmation of this observation will require recovery of the virus during outbreaks of RTI within this isolated community.

Adult↗
PubMed1979

Nosocomial infection linked to handwashing.

Study showed that sinks throughout a hospital harbored antibiotic-resistant gram-negative bacteria that had caused nosocomial infections and that could contaminate hands during washing.

Bacterial Infections↗
PubMed1979

Parainfluenzavirus upper respiratory tract illnesses in partially immune adult human subjects: a study at an Antarctic station.

Outbreaks of respiratory tract illnesses (RTI) in adult humans during October and November 1975 at McMurdo Station, Antarctica, were investigated by viral isolation and serologic procedures. The recovery of viral agents was enhanced by use of cell cultures in the field. Recoveries of parainfluenzaviruses types 1 and 3 and rhinoviruses were made from 10 of 39 nasal washings. Parainfluenzaviruses types 1 and 3 accounted for 50 and 30 per cent, respectively, of the total viruses recovered during October and November 1975. Acute and convalescent sera collected from 32 adult humans were examined for antiviral antibody by hemagglutination inhibition (HI) and radioimmunoassay (RIA) techniques. Serologic responses (HI and RIA) confirmed that parainfluenzaviruses were the predominent cause of RTI at McMurdo Station during that time. The temporal relationship between parainfluenzaviral diseases occurring in US communities and at McMurdo suggests that these viruses are transported to the Antarctic by personnel originating within the US. Standardization of the RIA allowed sequential assay of large numbers of sera using multiple preparations of radiolabeled indicator antibody, while ensuring the reproducibility of antiviral antibody titers to within one twofold dilution between subsequent labeled antibody preparations. The RIA detected both lower levels of virus specific antibody and more serologic responses than could be detected by HI.

Adult↗
PubMed1978

Rapid presumptive identification of Cryptococcus neoformans.

Carbohydrate-containing extracts were prepared from mature yeast colonies grown on Sabouraud dextrose agar by mixing a 0.001-ml loopful of yeast cells for 30 s in phenolized saline and removing the cells by centrifugation. Extracts were prepared from 54 Cryptococcus neoformans isolates, 29 isolates of other Cryptococcus species, 16 isolates of Candida species, 2 Rhodotorula, 2 Torulopsis, and 1 Saccharomyces species. Initially the carbohydrate content of each extract was estimated (Molisch method) and adjusted to 1, 5, and 10 microgram/ml. Twofold dilutions of each extract were tested for reactivity with the cryptococcal latex agglutination reagent of Bloomfield et al. (N. Bloomfield, M.A. Gordon, and D.F. Elmendorf, Jr., Proc. Soc. Exp. Biol. Med. 114:64-67, 1963). All 54 C. neoformans extracts gave strong agglutinations (3+ to 4+) in dilutions of 1:4 or greater. None of the other yeasts produced any agglutination, except for 1 of 15 C. laurentii isolates, which showed a 1+ reaction that disappeared at a dilution of 1:4 and above. Subsequent testing established that a single extract made from 0.001 ml of yeast cells in 6 ml of phenolized saline contained less than 5 microgram of carbohydrate per ml, was suitable for a single rapid screening dilution, and eliminated any cross-reaction from the C. laurentii isolates. In our hands this method has provided a reliable differentiation of C. neoformans from other unknown yeast colonies in less than 20 min exclusive of a Molisch determination.

Candida↗
PubMed1975

Effects of cytochalasin B on the intrcellular bactericidal activity of human neutrophils.

Cytochalasin B (CB) is known to have some inhibitory effects on cytokinesis, single-cell movement, bacterial uptake by phagocytes, and many other processes. The effects of CB on intraleukocytic bactericidal activities in human leukocytes were studied, and the results were summarized as follows. (i) CB inhibited the early stage of the intracellular bactericidal activity of human leukocytes against Streptococcus pyogenes D58 (group A). The effect was rapidly eliminated by rinsing the CB solution. (ii) In the late stage of the intracellular bactericidal process, however, CB possessed no effect against S. pyogenes D58 (group A) and Staphylococcus aureus 209P. (iii) CB also inhibited the translocation of myeloperoxidase granules to the phagosomes of human neutrophils.

Bacteria↗
PubMed1975

Relationship of early readings of minimal inhibitory concentrations to the results of overnight tests.

Broth dilution minimal inhibitory concentration (MIC) readings were compared after different incubation periods and with different inoculum concentrations. The purpose was to determine the best conditions for obtaining early results as close as possible to overnight readings. Initially, 76 antibiotic-organism combinations were tested using the International Collaborative Study technique and inoculum and were read after 3, 8, and 18 h of incubation. Approximately 28% of tests showed fourfold or greater increases in MICs after 18 h of incubation compared with the 3-h readings. No overnight MICs were lower than early readings. MICs of single antibiotics against seven organisms were also read with an automatic particle counter to confirm the validity of the visual readings. Experiments were made to determine whether inoculum manipulation could reconcile the differences between 3- and 18-h MIC results. One hundred and eight organism-antibiotic combinations were tested comparing 3-h MIC readings using an inoculum of 10(7) organisms per ml with overnight readings using 10(5) per ml. In 71 cases, readings with both inocula were within the range tested and 57 (86%) were within +/-1 log(2) of each other and followed an approximately normal distribution. Improved comparability between early read and overnight MICs thus may be achieved by inoculum manipulation, and this may be a suitable approach in the future development of automated procedures.

Anti-Bacterial Agents↗