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Biomedical subjects

C A Carter

Publications and source records attributed to C A Carter.

At least 91 records · Page 5Linked to original sources
PubMed1984

Ethotoin in seizures of childhood and adolescence.

Ethotoin is an anticonvulsant that was considered minimally effective when introduced, but due to its apparent lack of side effects, there has been renewed interest in the drug for use in generalized and psychomotor seizures. We have characterized the pharmacokinetics of ethotoin in children and have found nonlinearity. Seizures were controlled in 16 of 17 patients, and there were no side effects reported. Gingival hyperplasia due to previous phenytoin therapy improved in all cases.

Adolescent↗
PubMed1983

Effect of the prostaglandin synthetase inhibitor indomethacin on 7,12-dimethylbenz(a)anthracene-induced mammary tumorigenesis in rats fed different levels of fat.

The effect of the prostaglandin synthetase inhibitor indomethacin on the dietary fat enhancement of 7,12-dimethylbenz(a)anthracene-induced mammary tumorigenesis has been examined in female Sprague-Dawley rats. Rats were fed either a normal-fat or high-fat diet (5 or 18% corn oil, respectively) with or without 0.004% indomethacin, starting 3 days after a single intragastric intubation of 5 mg 7,12-dimethylbenz(a)anthracene. Results of this experiment demonstrated that indomethacin completely blocked the stimulatory effect of fat on tumorigenesis, as measured by a decreased tumor incidence, a decreased number of tumors per group, a decreased tumor size, and an increased latency. No effect of indomethacin was observed in rats fed the normal-fat diet. These data suggest that at least part of the stimulatory effect of polyunsaturated fat on 7,12-dimethylbenz(a)anthracene-induced mammary tumorigenesis may be mediated through an increased synthesis of prostaglandins.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

Experimental ulcerative herpetic keratitis. II. Influence of topical corticosteroid in immunised rabbits.

Since the great majority of patients possess immune response to herpes simplex virus (HSV), the influence of a topical anti-inflammatory corticosteroid (0.1% clobetasone butyrate) on ulcerative herpetic keratitis was studied in rabbits with a previous HSV skin infection (immunised) and compared with that in normal rabbits. Corticosteroid treatment had a much greater ulceration-exacerbating effect in immunised than in normal animals. On day 7 the mean area of ulceration in immunised rabbits were 3 times greater in treated eyes. 0.01% clobetasone butyrate treatment had less effect on immunised rabbits; 0.001% had no effect. It is concluded that the immunised rabbit provides a useful experimental model for studying the relationship between concentration of topical anti-inflammatory agents and enhancement of herpetic ulceration.

Animals↗
PubMed1981

Experimental ulcerative herpetic keratitis. III. Evaluation of hyperimmune gammaglobulin therapy.

The value of hyperimmune gammaglobulin (HGG) therapy in ulcerative herpetic keratitis was assessed in rabbits. HGG treated of early disease in normal rabbits was very effective, producing a 10-fold rise in the virus concentration needed to infect 50% of sites (CID50) and an 88% inhibition of ulceration after 2 days. The efficacy of the gammaglobulin preparations tested depended on their anti-HSV antibody content. Established disease was considerably less responsive to HGG therapy. No conclusive effect of HGG therapy could be demonstrated in rabbits with a previous HSV skin infection ('immunised'). Corticosteroid-induced geographic ulceration in immunised rabbits was not prevented by concurrent HGG therapy. The findings indicate that HGG is unlikely to represent a useful therapy for ulcerative herpetic keratitis but that it may be valuable in primary disease and in long-term prophylaxis.

Animals↗
PubMed1979

Polyadenylylation of proteins in reovirions.

The reovirus oligoadenylates exist in two states within the virion: free and bound to viral proteins. The latter class of oligonucleotides, after digestion with Penicillium (P1) nuclease, yields adenylic acid and an adenosine-containing compound that is positively charged at pH 1.7, 3.5, or 6.5. In a mixture of [35S]methionine- and [3H]adenosine-labeled reovirus disrupted by sodium dodecyl sulfate/urea, approximately 4% of the radioactivity in [35S]methionine-labeled proteins coelutes with [3H]adenosine-labeled material at a net charge of -1.5 when analyzed by ion-exchange chromatography on DEAE-cellulose. This material migrates in sodium dodecyl sulfate/polyacrylamide gels with mu polypeptides and with a small protein, viii. Radioactivity is not released when the complex is boiled in buffer containing sodium dodecyl sulfate and urea or boiled in 80% dimethyl sulfoxide or when viral RNA is extracted with phenol. Digestion with Pronase converts the [3H]adenosine-labeled compound to oligomers of net charge -8 to -12 which contain nuclease P1- and alkaline phosphatase-sensitive adenylic acid residues as well as adenosine in a P1- and phosphatase-resistant linkage. These data indicate that reovirus contains structural proteins that are covalently bound to an oligoadenylate moiety.

Mammalian orthoreovirus 3↗
PubMed1979

Energy cost of rehabilitation calisthenics.

This study examined the relationship between total energy cost and cardiac effort for a set of graded calisthenics that have been used in cardiac rehabilitation programs. Cardiac effort was quantified by calculating myocardial oxygen cost from the product of heart rate and systolic blood pressure. Total energy cost was determined by measuring oxygen uptake during steady-state exercise. Results indicate that total energy-cost values accurately reflect the cardiac effort required during the performance of these calisthenic exercises by normal subjects.

Adult↗
PubMedDate not supplied

Liquid and solid potassium chloride: bioavailability and safety.

Studies have suggested that microencapsulated preparations of potassium chloride may pose less risk to the upper gastrointestinal mucosa than the currently available wax-matrix preparations. Based on our own clinical experience and data available from the literature, we have concluded that (1) liquid and slow-release preparations of potassium chloride are safe and effective when used appropriately and (2) at present there is no conclusive evidence to suggest that lesions of the upper gastrointestinal tract are more prevalent with one slow-release preparation than with another.

Biological Availability↗
PubMedDate not supplied

Upper airway obstruction in a llama caused by aberrant nasopharyngeal bots (Cephenemyia sp.).

A 9 month old female llama was presented with inspiratory dyspnea. Radiographically, there was a large soft tissue mass nearly occluding the nasopharynx. During endoscopic examination three nasopharyngeal bots were identified embedded in the mass. The larvae were removed and the patient treated with ivermectin. The patient was discharged one week later free of clinical respiratory disease. In follow-up radiographs made 6 weeks later, only residual radiopacity in the area of the mass remained.

Airway Obstruction↗
PubMedDate not supplied

Effect of pH and nonphysiological salt concentrations on human immunodeficiency virus-1 protease dimerization.

Human immunodeficiency virus-1 (HIV-1) protease is catalytically active as a dimer of identical subunits that associate through noncovalent interactions. To investigate the forces stabilizing HIV-1 protease in its active form, we have studied the effects of pH and salts on structure and function of the enzyme. Enzymatic activity was measured by following the hydrolysis of a fluorogenic substrate. Dissociation of the dimer into its subunits was monitored by gel filtration, while conformational changes in the enzyme were probed by measurements of intrinsic tryptophan fluorescence. Mg2+ ions were capable of dissociating the dimeric enzyme with a concomitant red shift and increase in quantum yield of the tryptophan fluorescence, indicating increased accessibility of tryptophan to the aqueous environment. These structural changes also were associated with a loss of catalytic activity which was insensitive to substrate concentration, consistent with noncompetitive inhibition. Both structural and functional changes could be attributed to binding of Mg2+ ions to a site with an apparent dissociation constant of approximately 2 M. In contrast, increasing concentrations of Na ions up to 5 M were without effect. Increasing pH had similar effects on HIV-1 protease as increasing Mg2+ ions concentration, with concomitant dissociation into subunits, increase in quantum yield and red shift in tryptophan fluorescence, and loss in catalytic activity. The apparent pKa for these structural and functional transitions was 6.95 +/- 0.08. This value is consistent with that of an aspartic acid residue with an anomalously high pKa, which has been implicated in the catalytic activity of HIV-1 protease.

Amino Acid Sequence↗
PubMedDate not supplied

Confocal laser scanning microscopy of oncogene localization in rainbow trout cell lines derived from normal and tumor tissue.

We examined the localization and expression of the nuclear oncoprotein c-myc and the cytoplasmic membrane-associated oncoprotein c-ras in rainbow trout cell lines derived from both normal and tumor tissue in order to question whether c-myc and ras oncoprotein immunostaining was increased in cells derived from tumors compared to cells derived from normal tissue. Cell lines examined were derived from normal rainbow trout gonadal cells (RTG-2), a rainbow trout hepatoma (RTH-149), and a rainbow trout mesothelioma (RTM). Protein products of c-ras and c-myc were visualized in these 3 cell lines by employing fluorescein-labeled anti-mouse pan-ras and c-myc antibodies. The RTG-2 cells were used in this study as normal, control cells, and they exhibited little pan-ras and c-myc staining. The RTH-149 cell line (a tumorigenic cell line) exhibited positive pan-ras staining in regions of the membrane and cell cytoplasm. Localization of c-myc staining to perinuclear regions was punctate in RTH-149 cells. RTM cells (also a tumorigenic cell line) displayed a ras staining localization similar to the pattern seen in RTH-149 cells. RTM cells exhibit a diffuse perinuclear staining and, thus, display a more ubiquitous localization of c-myc than RTH-149 cells. Northern blot analysis indicated that c-myc expression was highest in RTM cells, whereas RTG-2 cells and RTH-149 cells expressed similar lower levels of c-myc expression. We were unable to detect significant ras expression in any of the cell lines by Northern blot analysis. In summary, the cell line derived from normal tissue, the RTG-2 cells, displayed little ras and c-myc immunostaining, whereas the cell lines derived from tumorigenic tissue, RTH and RTM cells, displayed increased immunostaining for c-myc and ras proteins.

Animals↗