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Biomedical subjects

J Jessop

Publications and source records attributed to J Jessop.

At least 37 records · Page 2Linked to original sources
PubMed1988

Comparison of blood agar, ampicillin blood agar, MacConkey-ampicillin-Tween agar, and modified cefsulodin-Irgasan-novobiocin agar for isolation of Aeromonas spp. from stool specimens.

The performance of four media for the isolation of Aeromonas strains from stool specimens, the importance of ampicillin-susceptible Aeromonas strains in the selection of culture media, and the usefulness of beta-hemolysis in screening blood-containing media for Aeromonas strains were evaluated in two phases. In the first phase, 36 of 1,672 stool specimens yielded Aeromonas isolates. Ninety-seven percent of the isolates were detected on blood agar containing 20 micrograms of ampicillin per ml (ABA), and 47% were detected on MacConkey agar containing 100 micrograms of ampicillin per ml and 1% Tween 80. In the second phase of the study, 43 of 1,924 stool specimens yielded Aeromonas isolates. Fifty-one percent of the isolates were detected on blood agar and on modified cefsulodin-Irgasan-novobiocin agar, and 84% were detected on ABA. The combination of ABA and modified cefsulodin-Irgasan-novobiocin agar provided 100% recovery of the Aeromonas isolates encountered. All of the Aeromonas isolates detected on blood agar were also detected on ABA, and 89% of the Aeromonas isolates detected on these media were beta-hemolytic. These results suggest that ABA is superior to the other media evaluated for the isolation of Aeromonas strains from stool specimens, but optimal recovery of the organism may require the use of more than one medium. The results also suggest that the occurrence of ampicillin-susceptible strains is not a limitation on the use of ABA, but at least 10% of Aeromonas isolates will be missed if beta-hemolysis is used to screen ABA plates for these organisms.

Aeromonas↗
PubMed1983

The Piper rhythm--a phenomenon related to muscle resonance characteristics?

The purpose of the present work is to examine the causes of the Piper rhythm, i.e. the tendency towards rhytmical 40-60 Hz grouping of motor unit potentials in steadily contracting human muscles. At weak or moderate contraction strength individual motor units exhibited preferred firing rates which were subharmonically related to the Piper rhythm in the gross EMG. Microelectrode muscle nerve recordings provided no support for the hypothesis that the Piper rhythm is dependent on resonance-induced rhythmical volleys of afferent spindle impulses causing reflex entrainment of motor impulses. This hypothesis also seems inconsistent with the findings that Piper rhythms of similar frequency appear in muscles with widely different mechanical properties and that the rhythms are about equally prominent in muscles with brisk as in muscles with weak or absent stretch reflexes. The results suggest that the Piper rhythm is dependent on some kind of pace-maker in the spinal cord or the cerebrum which tends to entrain and synchronize motor impulses.

Electromyography↗
PubMed1981

A study of amyloid arthropathy in multiple myeloma.

Forty-three patients with classical multiple myeloma were studied to assess the prevalence and characteristics of amyloid arthropathy using clinical, radiological, and histological methods. Two patients were found to have amyloid arthropathy, and a third case is described in detail. Complement and cryoprecipitate analysis of the synovial fluid, and electronmicroscopy of the synovium, synovial debris and cartilage were undertaken in an attempt to shed further light onto the pathogenesis of what has hitherto been regarded as a rare complication of multiple myeloma. Complement components were not depressed and no evidence of specific light chain containing immune complexes was found in synovial fluid cryoprecipitates. Histochemical and electron microscopic localization of amyloid in perichondrocytic lacunae as well as in synovial fluid debris, synovium and the articular cartilage surface suggest the possibility that chondrocytes and synovial macrophages may share a role in processing immunoglobulin components as a prelude to the formation of amyloid fibrils. Amyloid arthropathy occurs in about 5 per cent of patients with multiple myeloma. The clinical picture can resemble rheumatoid arthritis with median nerve compression in the carpal tunnel and symmetrical arthritis of the wrists and small joints of the hands. Diagnosis can be established by examination of Congo red stained synovial fluid sediments under polarized light even in the absence of other clinical features of amyloidosis and when rectal biopsy is negative.

Aged↗
PubMed1978

Development and standardization of a cytotoxic micro-assay for detection of enterotoxins: survey of enterotoxins from Escherichia coli of infant origin.

The development of a practical cytotoxic micro-assay for detection of enterotoxins in crude bacterial lysates of E. coli and other Gram-negative bacteria, is described. This quantitative assay is based on growth inhibition of mouse-fibroblasts, maintained in suspension or by inhibition of uptake of DNA precursors. Guidelines for performing the assay and evaluating the results by statistical considerations, are described. The choice of a relatively cheap medium and a suitable number of target cells to achieve cell doubling in 24 h is given. The concentrations of proteins in the crude lysates from strains of different origin, are not of equal potency; a predetermined but different protein concentration for strains from infants, adults or porcine origin, are recommended for detection of the toxins and for achieving reproducible results. Production of toxic proteins is enhanced by mitomycin C in toxigenic strains and not in non-toxigenic strains. Screening of a limited number of lysates from E. coli strains originating from infants and a comparison of the cytotoxicity of several known toxigenic and non-toxigenic strains from human adults and porcine origin, are presented.

Adult↗