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Biomedical subjects

V Campbell

Publications and source records attributed to V Campbell.

35 records · Page 2Linked to original sources
PubMed1993

Vapors from collodion and acetone in an EEG laboratory.

In the many EEG laboratories, the collodion-acetone technique has lost favor because of offensive vapors. We measured vapor concentrations of diethyl ether and acetone, the two principal vapors from this technique, to determine whether they reached toxic levels. We found that diethyl ether vapors usually reached the olfactory threshold, but acetone concentration did not. Neither reached concentrations that were systemically toxic. We then developed an inexpensive, effective method of reducing concentrated vapors during electrode application and removal and documented a significant reduction in vapor concentrations. With this information and with an inexpensive, "in house" vapor extraction system, technologist and patient satisfaction with the collodion method should greatly improve.

Acetone↗
PubMed1993

GABAB receptor modulation of Ca2+ currents in rat sensory neurones by the G protein G(0): antisense oligonucleotide studies.

1. Calcium channel currents (IBa) were recorded in cultured dorsal root ganglion neurones (DRGs), 24-32 h after microinjection with 20-mer phosphorothioate antisense oligonucleotides complementary either to a G alpha o or a G alpha i unique sequence, or with a nonsense sequence. 2. The ability of the GABAB agonist (-)-baclofen (50 microM) to inhibit IBa was examined. The maximum peak current was inhibited by 35.3 +/- 4.0% (n = 11) in control non-injected cells, and by 38.1 +/- 2.6% (n = 11) and 34.8 +/- 4.2% (n = 5) in nonsense- and G alpha i oligonucleotide-injected cells. Following G alpha o oligonucleotide injection, (-)-baclofen inhibited IBa by 21.0 +/- 3.2% (n = 19). 3. Confocal immunocytochemical localization of G alpha o showed prominent staining at the plasma membrane in control DRGs, and this was also present in G alpha i and nonsense oligonucleotide-injected cells. The G alpha o staining at the plasma membrane was reduced by 76% in G alpha o oligonucleotide-injected cells. In contrast, confocal immunocytochemical localization of G alpha i showed immunostaining in the membrane and cytoplasm of control, G alpha o- and nonsense-injected DRGs, whereas this was depleted by 68% in G alpha i oligonucleotide-injected cells. 4. These results indicate that the GABAB receptor couples to voltage-sensitive calcium channels via the G protein G(o) and not Gi, and that antisense oligonucleotides can be used to deplete G proteins in DRGs.

Animals↗
PubMed1991

Molecular cloning of a gene encoding the histamine H2 receptor.

The H2 subclass of histamine receptors mediates gastric acid secretion, and antagonists for this receptor have proven to be effective therapy for acid peptic disorders of the gastrointestinal tract. The physiological action of histamine has been shown to be mediated via a guanine nucleotide-binding protein linked to adenylate cyclase activation and cellular cAMP generation. We capitalized on the technique of polymerase chain reaction, using degenerate oligonucleotide primers based on the known homology between cellular receptors linked to guanine nucleotide-binding proteins to obtain a partial-length clone from canine gastric parietal cell cDNA. This clone was used to obtain a full-length receptor gene from a canine genomic library. Histamine increased in a dose-dependent manner cellular cAMP content in L cells permanently transfected with this gene, and preincubation of the cells with the H2-selective antagonist cimetidine shifted the dose-response curve to the right. Cimetidine inhibited the binding of the radiolabeled H2 receptor-selective ligand [methyl-3H]tiotidine to the transfected cells in a dose-dependent fashion, but the H1-selective antagonist diphenhydramine did not. These data indicate that we have cloned a gene that encodes the H2 subclass of histamine receptors.

Amino Acid Sequence↗
PubMed1991

Pseudoaneurysm of the popliteal artery as a complication of an osteochondroma. A review of the literature and a case report.

False aneurysm of the femoral artery was associated with a solitary osteochondroma of the femur in a 22-year-old man. An extensive review of the literature and the problems related to diagnosis revealed that the aneurysm was apparently unique. Contrary to previous reports, computed tomography and angiography did not establish the diagnosis. The physical findings were more informative.

Adult↗
PubMed1990

Product-line management defined.

PLM will have a significant impact on an organization's mission, management philosophy, marketing plan, and most definitely, day-to-day operations. PLM offers an alternative to traditional management approaches for the medical record department and the health care industry as a whole. The medical record professional should understand PLM both as a hospital wide structure and as an internal structure used to maximize departmental productivity and use of resources.

Hospital Administration↗
PubMed1989

Stimulation of protooncogene expression by partial hepatectomy is not tissue-specific.

We have characterized the early protooncogene response and the later cell proliferative response in the kidneys and livers of normal rats cross-circulated with partially hepatectomized animals. Increase c-myc and C-Ha-ras expression was observed in the kidneys of totally hepatectomized rats, as well as those of their cross-circulated partners. This indicates that the initial response to hepatectomy is not organ-specific, although the later DNA synthetic response of the kidney is only approximately one-tenth that of regenerating liver. Expression of c-myc and c-Ha-ras is dramatically increased in the livers of both hepatectomized and nonhepatectomized, parabiotic (cross-circulated) rats within 1 hr of partial hepatectomy, confirming the presence of a circulating factor which stimulates protooncogene expression early in regeneration. DNA synthesis was also stimulated in the livers of the cross-circulated animals between 20 and 26 hr following hepatectomy, but only to a level one-eighth that of the livers of hepatectomized animals. Normal rats cross-circulated with totally hepatectomized animals also demonstrated an early increase in hepatic c-myc and c-Ha-ras expression, indicating that regeneration must be stimulated by an extrahepatic signal. Our data suggest that the early increase in protooncogene expression is a non-organ-specific response to partial hepatectomy which does not insure subsequent cellular proliferation. The organ specificity of liver regeneration must involve an event separate from the early stimulation of protooncogene expression.

Animals↗
PubMed1984

Immunofluorescent studies of the rat adipocyte cell surface.

Antibodies against rat adipocyte plasma membranes have been shown to mimic insulin action in isolated adipocytes (Pillion & Czech, J. biol. Chem. Vol. 253, pp. 3761 - 3764, 1978). Immunofluorescent studies with antimembrane antibodies reveal capping on the adipocyte cell surface. Dose - response studies showed that the number of fat cells with obvious caps did not increase as the concentration of antimembrane antibodies was increased, whereas stimulation of glucose oxidation was proportional to the antibody concentration. At fairly high dilutions of antiserum there was no effect on rat adipocyte glucose oxidation, but caps were still visible, suggesting that there is not a direct correlation between capping and stimulation of adipocyte metabolism. At 15 degrees C, it was found that capping was not significantly impaired, while the basal rate of glucose oxidation was reduced considerably. Both insulin and antimembrane antibodies were still able to stimulate glucose oxidation at 15 degrees C, although the maximal rate of glucose oxidation which could be achieved at this temperature was considerably lower than that observed at 37 degrees C. Fat cells that were fixed with paraformaldehyde before being exposed to antimembrane antibodies showed a similar number of caps to unfixed cells, suggesting that some fat cells had a polarized distribution of membrane antigens even before exposure to antimembrane antibodies. These results demonstrate for the first time that antibodies against the rat adipocyte plasma membrane, which are known to mimic insulin action on rat fat cells, can associate with antigens arranged non-randomly on the cell surface, but it appears unlikely that capping plays a critical role in the expression of this biological activity.

Adipose Tissue↗
PubMed1982

Adaptive behavior scale differences in scores of mentally retarded individuals referred for institutionalization and those never referred.

Adaptive Behavior Scale profiles of 68 mentally retarded individuals referred for institutionalization were compared with a matched sample of retarded individuals who were never referred for institutionalization. A discriminant analysis identified the following six domains that, in combination, accounted for the significant differences between groups: Violent and Destructive Behavior, Sexual Aberrations, Hyperactivity, Antisocial Behavior, Physical Development, and Socialization. Implications for the effectiveness of an abbreviated ABS measure for diagnostic purposes and program planning in community and institutional settings were discussed.

Adaptation, Psychological↗
PubMedDate not supplied

A comparison of acute reversible pre- and postsinusoidal portal hypertension on salt and water retention in the dog.

To define the relationship between portal hypertension and renal excretion of salt and water, two acute animal models of portal hypertension were investigated. In both models, it was necessary for systemic and renal hemodynamics to remain unchanged during the creation of portal hypertension so as to eliminate the effects of change in these parameters on renal excretion. In eight dogs, portal hypertension was induced by controlled tightening of a ligature around the superior hepatic vein and changes in hemodynamics were prevented by controlled i.v. titration with canine plasma. Rises in portal pressure 9.3 +/- 2.6 to 15.6 +/- 2.3 cm H2O were associated with significant decreases in urine volume 1.57 +/- 0.53 to 0.66 +/- 0.21 ml per min (p less than 0.05) and urinary sodium excretion [340 +/- 82 to 145 +/- 75 mEq per min (p less than 0.05)]. In contrast, similar experiments in five dogs in which the portal vein was partially ligated with increases in portal pressure from 8.3 +/- 0.6 to 18.6 +/- 0.5 cm H2O resulted in no change in urinary volume or sodium excretion. Acute reversible portal hypertension induced by hepatic vein constriction is associated with acute reversible retention of water and salt in the absence of changes in renal blood flow and creatinine clearance which only occur when the liver is involved and not with portal vein constriction.

Acute Disease↗
PubMedDate not supplied

Acute opioid withdrawal on accidental injection of naltrexone.

We report two 16-year-old female intravenous drug users who, after making purchases from street suppliers, both presented with symptoms of acute opioid withdrawal. Urine toxicology revealed naltrexone, a long-acting opioid antagonist used in detoxification and maintenance therapy in opioid dependence. While the safety and efficacy of opiate antagonist treatment is being debated, the present case highlights the vulnerability of this young population. The recent availability of non-prescribed opiate antagonists suggests that both health professionals and young people themselves need to be aware of their effects.

Adolescent↗
PubMedDate not supplied

Clinical experiences: development of a medical surveillance protocol for hazardous waste workers.

Medical surveillance of hazardous waste workers is essential for the health of these workers, who have unique, complex exposures. In order for this preventive tool to be effective, the supervising and/or examining physician must be educated about the specific health risks of hazardous waste workers and also must perform a comprehensive examination. Results of testing should be evaluated both for remarkable abnormalities as well as longitudinal subtle changes in individuals, and also for trends in workers with similar exposures. Fitness for duty determinations should be then made with appropriate communication of abnormalities and follow-up recommendations to both employers and employees. To date, clinical and research findings from clinical centers performing surveillance examinations on hazardous waste workers have not revealed remarkable abnormalities related to their potential exposures. The possible causes for these results include: (1) the workers have been well protected; (2) the current diagnostic methodologies are not sensitive enough to detect pathophysiologic changes; and (3) disease may not yet be manifest due to latency or cumulative effects of long-term low-dose exposure. In addition, one must keep in mind that previous clinical and research data were collected from test results of workers who were mainly involved in feasibility, as opposed to remediation, activities. With the prospective change of more clean-up involvement of hazardous waste workers, their potential for exposure may increase. Therefore, periodic collaborative evaluation of existing surveillance programs' results (e.g., every 5 years) is advised. This would allow determination of the efficacy of the current diagnostic methods in detecting disease, as well as the possible inclusion of more sensitive and/or specific newer technologies for use on a more routine basis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Demography of the hazardous waste industry.

This article attempts to characterize the workforce of the hazardous waste industry. The growth of the industry is discussed, including its deployment into various activity categories, and its size is estimated. Finally, demographics of the workforce are presented.

Adult↗