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Biomedical subjects

D W Morgan

Publications and source records attributed to D W Morgan.

At least 127 records · Page 7Linked to original sources
PubMed1984

Enhancing supervision of psychotherapy.

This paper reports the efforts of a psychiatry training faculty to explicitly study the supervisory process and enhance the faculty's supervisory skills. To accomplish this, a psychiatry resident permitted the videotaping of her supervision. These videotapes were then reviewed and presented in an ongoing conference to members of the training faculty. Through these conferences, the faculty was able to learn methods of elucidating issues within the supervisory process. Techniques for assisting residents in the development of their psychotherapeutic skills were elaborated.

Adult↗
PubMed1983

Activity of 10 naphthoquinones, including parvaquone (993C) and menoctone, in cattle artificially infected with Theileria parva.

Ten naphthoquinones, including parvaquone (993C) (Clexon; Wellcome) and menoctone, were tested for activity in cattle artificially infected with Theileria parva, the causative organism of East Coast fever (ECF). Parvaquone cured all 14 cattle treated with a single dose of 20 mg/kg intramuscularly and all five treated twice with 10 mg/kg intramuscularly. Menoctone cured seven of 10 cattle treated with a single dose of 5 mg/kg intramuscularly. Of 25 untreated control cattle, 22 died of ECF. None of the remaining eight naphthoquinones was as active as parvaquone. Three esters of active naphthoquinones, designed as 'prodrugs' of their parent compounds, showed little or no activity in infected cattle despite being highly active in vitro against T parva. These results were instrumental in the selection of parvaquone for development as the first specifically active remedy for ECF.

Animals↗
PubMed1982

Toxicity study of oxfendazole in pregnant sows.

The safety of oxfendazole when administered to pregnant sows was assessed. Thirty-six pregnant sows were dosed orally on repeated occasions at dose rates of 4.5 mg/kg bodyweight and 13.5 mg/kg during the critical period of embryo organogenesis and implantation. Twelve sows were observed as untreated controls. Oxfendazole was administered as 6.48 per cent medicated pellets. Records were kept of the reproductive performance of all 48 sows. There were no obviously drug-related clinical signs of toxicity in the sows after treatment with oxfendazole, neither were drug-related anatomical or behavioural abnormalities detected in the newborn pigs.

Abnormalities, Drug-Induced↗
PubMed1982

Modulation by thyroid status of hepatic low Km phosphodiesterase.

The effects of thyroid status on the activity of hepatic cAMP phosphodiesterase (PDE) were studied in the rat. Male rats were rendered hyperthyroid by treatment with T3 or hypothyroid by treatment with propylthiouracil. The hepatic particulate low Km PDE was solubilized, and its activity was measured at concentrations of 0.12-1.3 microM cAMP. The Km decreased in hypothyroidism and tended to increase in hyperthyroidism with respect to individual controls. The maximal velocity (Vmax) was unaffected by changes in thyroid status. The increases in Km correlated with increasing plasma T3, whereas the Vmax did not. Concentrations of cAMP increased in the livers from hyperthyroid rats and decreased in those from hypothyroid, in comparison with euthyroid rat livers. The effects of thyroid status on various aspects of hepatic lipid metabolism reported from this laboratory may, in part, have resulted from alterations in hepatic cAMP concentrations. These alterations, may have resulted secondarily from changes in the activity of hepatic PDE by changes in the Km for cAMP with little change in the Vmax.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1982

Comparison of the antitheilerial effect of Wellcome 993C and halofuginone.

The efficacy of Wellcome compound 993C and halofuginone was compared using cattle artificially infected with Theileria parva and using in vitro cultures of T parva. At a total dose of 20 mg/kg administered by the intramuscular route, 993C cured all nine cattle of advanced theileriosis and no major recrudescences of the infection occurred. Halofuginone was given by mouth at 1.2 mg/kg and cured five cattle of early clinical theileriosis, but significant recrudescences of infection occurred. Halofuginone at 1.2 mg/kg cured a further five out of six cattle with advanced theileriosis, but four of the five survivors developed moderate to severe resurgences of infection. The dose of 20 mg/kg of 993C was known to be close to its effective level, but 1.2 mg/kg halofuginone, the dose used by earlier workers, may not have been adequate. All 10 untreated control cattle died of acute theileriosis. The in vitro EC50 of both compounds was 0.003 mg per litre but, whereas the dose response curve of 993C was sigmoid, that of halofuginone was bellshaped. This may reflect toxicity to the host lymphoblastoid cells with higher concentrations of halofuginone.

Animals↗
PubMed1982

Effects of triiodothyronine and propylthiouracil on plasma lipoproteins in male rats.

Hyperalphalipoproteinemia, characterized by increased plasma concentrations of apoA-I and of HDL lipid and protein, was observed in rats treated with triiodothyronine (T(3)) for 7 days. The increase in the plasma HDL apoproteins was general for apoC, apoE plus A-IV, and apoA-I, as determined by isoelectric focusing. Hypotriglyceridemia, characterized by decreased concentrations of VLDL and apoB, was also observed in the hyperthyroid state. Although in the mildly hypothyroid animals (propylthiouracil-treated), hepatic metabolism of free fatty acid is shifted toward esterification to triglyceride and VLDL formation, as we reported previously, plasma HDL and apoA-I concentrations were not different from control plasma values, while the d 1.006-1.063 g/ml (IDL + LDL) lipoprotein fraction tended to be increased. In general, the proportion of apoE in the (IDL + LDL) fraction of the hypothyroid rat was greater than in controls and hyperthyroid animals, while the proportion of apoE tended to be lower in VLDL from both hypo- and hyperthyroid rats than in VLDL from controls. An enhanced release of apoA-I by perfused livers isolated from rats treated with T(3) was also observed; this enhanced output of apoA-I may explain, in part, the hyperalphalipoproteinemia observed in these rats. The depressed net output of apoA-I in vitro by perfused livers from rats treated with propylthiouracil (PTU) was not expressed in a statistically significant diminished plasma concentration of HDL or apoA-I in the intact animals. Treatment with T(3) also resulted in modification of the content of essential fatty acids in various lipid classes. Linoleic acid residues were significantly reduced and arachidonic acid content was increased in plasma phospholipids and esterified cholesterol in T(3)-treated rats. However, the relative fatty acid composition of unesterified fatty acids and triglyceride fatty acids was not altered by T(3) treatment. PTU treatment had no effect on fatty acid distribution in any of the plasma lipids. Secretion of biliary lipids was increased in perfused livers from T(3)-treated rats, while treatment with PTU did not affect release of lipids in the bile. These observations suggest a regulatory role for thyroid hormones that determine concentration and composition of plasma HDL and other lipoproteins.-Wilcox, H. G., W. G. Keyes, T. A. Hale, R. Frank, D. W. Morgan, and M. Heimberg. Effects of triiodothyronine and propylthiouracil on plasma lipoproteins in male rats.

Animals↗
PubMed1981

Effects of chronic reserpine administration on beta adrenergic receptors, adenylate cyclase and phosphodiesterase of the rat submandibular gland.

Chronic administration of reserpine to rats resulted in a doubling of the density of beta adrenergic receptors in submandibular gland membranes as determined by [3H]dihydroalprenolol binding. The affinity of the labelled drug for the receptor were not altered. There was a concomitant increase in the isoproterenol-stimulated cyclic AMP levels in slices of the gland when incubated in the absence of a phosphodiesterase inhibitor. However, this increase in cyclic AMP accumulation appears to be related to a decrease in phosphodiesterase activity rather than to the increase in the density of beta receptors, since glands from control and reserpinized animals accumulated equal amounts of cyclic AMP when incubated in the presence of a phosphodiesterase inhibitor. In addition, there was no difference between glands from controls and reserpine-treated rats in catecholamine-stimulated adenylate cyclase activity, but the Vmax of the phosphodiesterase was decreased 36% in glands from the treated animals. Similar results were obtained when control and surgically denervated glands were compared. The increase in beta adrenergic receptors appears to be the result of the depletion of norepinephrine due to reserpine administration, whereas the decreased phosphodiesterase activity may result from decreased cyclic AMP levels, secondary to the decrease in norepinephrine.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1980

A field trial to determine the effect of fly control using permethrin on milk yields in dairy cattle in the UK.

Permethrin, applied by knapsack sprayer or spray arch, was used to control flies on cattle in two dairy herds in the United Kingdom. The spray washes were applied at nominal rates of 0.5 litre of 0.1 per cent permethrin per animal and 1.0 litre of 0.05 per cent permethrin per animal respectively. The individual milk yields of two groups of cows were recorded before and after treatment. In both cases there was a significant increase in milk yield after treatment. The mean yield per cow per day during the trial period rose by 0.8 kg in one group and by 1.0 kg in the other group, after treatment. Assessments were made throughout the trial of the level of infestation of Stomoxys calcitrans, Haematobia irritans and non-biting flies.

Animals↗
PubMed1980

Field trials to assess the efficacy of permethrin for the control of flies on cattle.

Permethrin [3-phenoxybenzyl (+/-) cis, trans--2,2dimethyl-3-(2,2-dichlorovinyl) cyclopropane-1-carboxylate], a new synthetic pyrethroid, was applied to cattle on farms in the United Kingdom to assess its efficacy in fly control under field conditions. When 250 ml 0.1 per cent permethrin was applied to the backs of cattle using a knapsack sprayer, adequate control of horn flies, Haematobia irritans, was achieved for over three weeks. Application of 500 ml 0.1 per cent all over each animal gave one to two weeks' control of stable flies, Stomoxys calcitrans, and satisfactory control of non-biting flies for one week. Application of permethrin through a spray arch, using approximately one litre 0.05 per cent permethrin for each animal, gave similar control.

Administration, Topical↗
PubMed1977

Heroin use among soldiers in the United States and Vietnam: a comparison in retrospect.

A "unique" heroin epidemic was claimed to exist among American soldiers in Vietnam in the early 1970s. To assess this claim, in 1972 we simultaneously evaluated heroin use in two similar military populations in the United States and Vietnam and compared findings with previous Vietnam studies. The total percentage ever reporting use of heroin was comparable in both locations. Recent use, however, was significantly higher in Vietnam. Heroin users, regardless of location, were demographically and psychosocially more similar than different. Any conclusion that the heroin epidemic in Vietnam was grossly "unique" seems unwarranted.

Disease Outbreaks↗
PubMed1975

A diagnostic wax-up technique.

A procedural outline has been presented for the accomplishment of a diagnostic wax-up as a preliminary step to actual preparation of the teeth as suggested by the proponents of gnathologic techniques. 8.9) The use of this technique will decrease the possibility of error in the construction of any extensive fixed partial denture prosthesis. The success of any procedure required the willingness of general dentists and specialists to, 'Spend more time planning than doing.'

Dental Equipment↗
PubMed1975

Alcohol use in the Army: patterns and associated behaviors.

The authors assessed by questionnaire the alcohol use of 1,873 U.S. soldiers in the United States and Viet Nam. According to operational definitions based on total ethyl alcohol consumption and several behaviors associated with drinking, 7 percent were classed as alcoholics, 5 percent as borderline alcoholics, and 24 percent as potential alcoholics. Contrary to popular stereotypes, there was a disproportionate number of younger and lower ranking soldiers in these three groups; there was also a positive relationship between drinking and use of illicit drugs across groups. The authors state that future studies of alcohol use should include determinations of total ethyl alcohol intake to permit generalizability of their results.

Adolescent↗
PubMed1975

Treatment of depression in alcoholics.

The authors compared two groups of depressed alcoholics given either placebo or chlordiazepoxide-imipramine in a double-blind study. Although depression decreased in both groups, there were no significant differences between them on any of three pre- and posttreament measures. The Zung scale showed that medication decreased depression significantly, however, this finding was not supported by the Beck Depression Inventory or by the Minnesota Multiphasic Personality Inventory, indicating the necessity for use of multiple assessment instruments.

Adolescent↗