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Biomedical subjects

D J Johnson

Publications and source records attributed to D J Johnson.

At least 109 records · Page 6Linked to original sources
PubMed1975

A natural case of Schistosoma mansoni in the chimpanzee (Pan troglodytes versus).

A spontaneous infection with Schistosoma mansoni was found in a chimpanzee (Pan troglodytes versus) recently imported from Sierra Leone, Africa. Clinical signs consisted of anemia, liver enlargement, bronchial rales, and emaciation. The primary gross pathologic lesions included a fibrotic firm nodular liver and pulmonary edema and consolidation. Histopathologic examination revealed changes similar to the experimental syndrome of Manson's schistosomiasis in the chimpanzee. The diagnosis was confirmed by the presence of the eggs and larvae of Schistosoma mansoni.

Anemia↗
PubMedDate not supplied

Posttraumatic skeletal muscle proteolysis: the role of the hormonal environment.

To investigate the role of hormones as mediators of net skeletal muscle proteolysis following injury, healthy normal male volunteers received a continuous 76-hour infusion of the 3 "stress" hormones: hydrocortisone, glucagon, and epinephrine. As a control, each subject received a saline infusion during another 4-day period. Ten paired studies were conducted. Diets were constant and matched on both occasions. Triple hormone infusion achieved hormone concentrations similar to those seen following mild-moderate injury. After 72 hours of infusion, skeletal muscle intracellular glutamine concentrations were lower in the hormone studies than in the control group (N = 4). Free amino acid concentrations in arterial whole blood and forearm amino acid efflux were little affected by hormonal infusion. Thus, alteration of the hormonal environment by the triple hormone infusion was not a sufficient stimulus to induce all of the changes in skeletal muscle proteolysis observed in critical illness. Since studies utilizing neurohormonal blockade have shown diminished net muscle proteolysis, the stress hormones appear to be necessary but not sufficient for the protein catabolic response to injury.

Amino Acids↗
PubMedDate not supplied

The measurement of 2-thiothiazolidine-4-carboxylic acid as an index of the in vivo release of CS2 by dithiocarbamates.

Dithiocarbamates and their disulfides are used extensively as agricultural fungicides, as accelerators of the vulcanization process of rubber in industry, and as therapeutic agents in medicine. The widespread uses of these compounds in agriculture, industry, and medicine provide many avenues of exposure to the human population. Subchronic to chronic exposures to some dithiocarbamates have resulted in the development of neuropathy in humans and experimental animals. Decomposition to CS2 presents a potential mechanism through which the toxicity of dithiocarbamates may be mediated. The purpose of this study was to determine the potential of dithiocarbamates to release CS2 in vivo. The ability to release CS2 was assessed by measuring urinary 2-thiothiazolidine-4-carboxylic acid (TTCA), which is used in industry to measure the exposure of workers to CS2. In this study, rats were housed individually in metabolic cages and given daily equimolar ip or po doses (1.5 mmol/kg) of N,N-diethyldithio-carbamate (DEDC), disulfiram (DS), N-methyldithiocarbamate (NMDC), or CS2 for 5 days, and TTCA was measured in urine collected at 24 h intervals. For each compound administered, TTCA was produced in all of the treated animals and the amount of TTCA eliminated in urine from po administration was significantly greater than that from ip administration. The relative rates of TTCA elimination in urine were DS > DEDC approximately equal to CS2 > NMDC for both routes of administration. Following administration of N,N-diethyl[13C = S] dithiocarbamate, carbon-13 enrichment at the thiocarbonyl carbon of TTCA was demonstrated using 13C NMR. Analysis of urinary TTCA proved to be useful both for establishing the in vivo release of CS2 by dithiocarbamate containing compounds and for evaluating the bioavailability of CS2. The results appear especially relevant to disulfiram, which is given orally for sustained periods in the treatment of alcoholism and has resulted in the development of neuropathy in susceptible individuals.

Administration, Oral↗
PubMedDate not supplied

Maintenance of skeletal muscle intracellular glutamine during standard surgical trauma.

Skeletal muscle glutamine (GLN) concentration falls following injury and infection. In an attempt to prevent this decline and to characterize its influence on the efflux of amino acid (AA) from skeletal muscle, we administered varying quantities of AA (0,2, and 4 g/kg X day) as saline or AA solutions with or without GLN enrichment to 22 postoperative dogs. Plasma and muscle AA were determined before and 24 hr after standard laparotomy. Hindquarter AA efflux was measured at 6 and 24 hr. Skeletal muscle nitrogen declined in saline controls (69.8 +/- 8.5 vs 52.8 +/- 8.4 mmol/liter; p less than 0.01), largely due to the fall in intracellular GLN (21.48 +/- 3.21 vs 15.86 +/- 3.80; p less than 0.05). Similar alterations were seen in the animals receiving 2 g/kg. However, both intracellular nitrogen and GLN were maintained in animals receiving 4 g/kg, whether the AA solutions contained GLN or not (skeletal muscle nitrogen before 64.3 +/- 8.6 mmol/l vs 65.4 +/- 7.0 after, GLN 19.2 +/- 3.4 vs 19.9 +/- 3.0). Hindquarter AA efflux was reduced in those animals at 6 hr compared with saline-treated animals (-6.52 +/- 1.8 and -7.70 +/- 5.90 vs -19.05 +/- 4.06 mumol/kg X min; p less than 0.05). Intracellular GLN can be maintained during operative stress with adequate nitrogen infusion. Replacing 50% of the balanced AA solution with GLN resulted in equally effective maintenance of intracellular GLN levels and a comparable reduction in skeletal muscle AA efflux. Preservation of normal intracellular GLN levels with adequate AA nutrition may be essential for the conservation of muscle protein.

Amino Acids↗
PubMedDate not supplied

Equine West Nile encephalitis, United States.

After the 1999 outbreak of West Nile (WN) encephalitis in New York horses, a case definition was developed that specified the clinical signs, coupled with laboratory test results, required to classify cases of WN encephalitis in equines as either probable or confirmed. In 2000, 60 horses from seven states met the criteria for a confirmed case. The cumulative experience from clinical observations and diagnostic testing during the 1999 and 2000 outbreaks of WN encephalitis in horses will contribute to further refinement of diagnostic criteria.

Animals↗
PubMedDate not supplied

Detection of North American West Nile virus in animal tissue by a reverse transcription-nested polymerase chain reaction assay.

A traditional single-stage reverse transcription-polymerase chain reaction (RT-PCR) procedure is effective in determining West Nile (WN) virus in avian tissue and infected cell cultures. However, the procedure lacks the sensitivity to detect WN virus in equine tissue. We describe an RT-nested PCR (RT-nPCR) procedure that identifies the North American strain of WN virus directly in equine and avian tissues.

Animals↗
PubMedDate not supplied

Telephone care as an adjunct to routine medical follow-up. A negative randomized trial.

CONTEXT: In 1992, a randomized trial at one outpatient clinic demonstrated that making telephone appointments part of routine medical follow-up could save money and reduce hospitalization. OBJECTIVE: To ascertain the effects of telephone care in other clinics. DESIGN: Consenting patients of 20 physicians were randomly assigned to receive telephone care or usual care. SETTING: Veterans Affairs General Medical Clinics in Denver, Colorado, and Sioux Falls, South Dakota. PATIENTS: 512 predominately male elderly veterans (mean age, 68 years) who had a broad range of chronic medical conditions. INTERVENTION: At the intake clinic visit, the recommended revisit interval (e.g., return in 3 months) for telephone care patients was doubled (e.g., return in 6 months) and three intervening telephone appointments were scheduled. Three telephone appointments were also scheduled at all subsequent clinic visits. MAIN OUTCOME MEASURES: Utilization of services and self-reported health status. RESULTS: More than 2000 calls were made during the 2-year study period. Although the revisit interval was longer for telephone care patients after the intake visit (as was expected), it was the same for both telephone care and usual care patients after all subsequent visits, despite the scheduling of three telephone appointments for telephone care patients. The intervention had no effect on self-reported health status, hospital admission, or number of deaths. The intervention also had no effect on the total number of clinic visits, outpatient laboratory tests, or radiologic tests. Telephone care patients had fewer unscheduled visits than did usual care patients (2.0 vs. 2.8 visits/patient; P = 0.01). CONCLUSION: Telephone care had little effect in this study. Instead of providing a way to maintain contact with patients without requiring them to appear in clinic frequently, telephone appointments became simply an additional service.

Aged↗