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Biomedical subjects

D Hopkins

Publications and source records attributed to D Hopkins.

At least 55 records · Page 3Linked to original sources
PubMed1992

Extending patient-controlled analgesia to patient-controlled neuroleptanalgesia.

A trial was conducted (among 22 patients) to assess a new use of patient-controlled devices. Using a patient-controlled analgesia (PCA) pump under the anaesthetist's guidance, the patients self-administered a neurolept mixture consisting of droperidol and alfentanil. The patients were then able to undergo minor surgery (dilatation and curettage). The majority remained detached, sedated and pain-free, while able to control the PCA pump during the procedure. Patient-controlled neuroleptanalgesia or PCNA, as we propose to call this technique, appeared practical, effective and safe. The method was generally well accepted and highly rated by the patients.

Adolescent↗
PubMed1991

[Current status of the global campaign to eradicate dracunculiasis (guinea worm disease)].

Dracunculiasis is eradicable because it is easy to diagnose, it is only transmitted by drinking water, there is no animal reservoir, and there are three ways to prevent the infection. Global 2000 is assisting guinea worm eradication Programmes in Pakistan, Ghana and Nigeria. The draft criteria for certification of dracunculiasis elimination and the resolutions adopted during the 3rd African Regional Conference on dracunculiasis were described. The progress of Pakistan's guinea worm eradication Programme, which has nearly achieved its goal and the accomplishments of the eradication Programme in Nigeria, which is thought to have the most case of guinea worm in the world were described. Evidence of socio-economic impact of dracunculiasis, vector control, local treatment and case containment were presented during the question and answer period.

Animals↗
PubMed1989

Surveillance: the foundation for control and elimination of dracunculiasis in Africa.

The International Drinking Water Supply and Sanitation Decade (1981-1990) has stimulated a movement to eradicate human infection with the helminthic parasite Dracunculus medinensis (dracunculiasis), whose victims are disabled for weeks or months during the painful emergence of one or more worms from beneath the skin. Each year, millions of people acquire this infection by drinking unclean water. Among the critical activities that are necessary for the elimination of dracunculiasis, one of the most fundamental is that of epidemiological surveillance. Surveillance activities play a key role in the strategy to target affected villages for improved water supplies and other control activities. Accurate surveillance data also stimulate interest and support for national eradication programmes. Dracunculiasis is a condition with excellent characteristics for reporting through passive surveillance systems. However, active surveillance, as well as other innovative surveillance strategies, should be used to establish baseline information in those villages where cases occur, and later to monitor epidemiologically important indices needed to evaluate the progress of elimination efforts.

Africa↗
PubMed1985

The relation of faculty academic activity to financing sources in a department of medicine.

Academic medical departments confront important changes in funding sources and consequent pressure to change faculty activities. Valid information has often been lacking concerning the existing relations of faculty activity to funding sources. We examined those relations in the Stanford Department of Medicine through a combination of randomized observations of faculty and faculty self-reports over a period of one year. For an average 62-hour workweek, there was approximate consonance between types of activities and sources of salary support. Sensitivity analyses indicated that even sizable errors in self-reports would not have changed the outcomes substantially. Over 60 per cent of the activity involved "joint products," representing two or more categories of activity. There was wide variation in activities and fund sources between divisions. Per full-time faculty equivalent, research generated far more income than the most lucrative specialty practice; thus, at least in this type of department, attempts to compensate for lost research revenue by intensifying clinical practice will probably fail and undermine present research activities. The method of analysis used here may be useful in improving prospective planning by departments and by larger medical-policy bodies, particularly in the public sector.

Academic Medical Centers↗
PubMed1985

Reduction in prostatic concentration of endogenous dihydrotestosterone in rats by hyperprolactinemia.

Persistently high levels of circulating prolactin can be achieved in male rats when pituitaries from female donors are grafted under the renal capsule. Enhanced growth of the lateral prostate can be accomplished by an apparent synergistic effect of excess prolactin with subphysiologic doses of testosterone. To define this effect we measured the endogenous dihydrotestosterone (DHT) concentrations in rat prostate lobes. Twenty Sprague-Dawley male rats (250 g) were castrated and given subcutaneous implants of silastic tubing filled with 1 cm of crystalline testosterone. Ten of these rats simultaneously received two pituitary grafts under the renal capsule. The remaining ten rats received intrarenal skeletal muscle grafts as controls. Four weeks later, the weight (mg +/- SE) of the ventral and dorsal lobes were not significantly different between the two groups, while the lateral lobe was significantly (P less than 0.01) heavier in rats with pituitary grafts (121.4 +/- 7.5) than in controls (81.7 +/- 10.4). Endogenous DHT in the tissue extracts was determined by radioimmunoassay following KMnO4 treatment to eliminate testosterone. The concentration of DHT (ng/g tissue +/- SE) was significantly (P less than 0.01) lower in the lateral prostate of graft-bearing animals (4.40 +/- 0.29) than in the controls (5.98 +/- 0.34). These results indicate that, in the rat, hyperprolactinemia induced by pituitary grafts is associated with a heavier lateral prostate and a lower concentration of endogenous DHT in that tissue. These results also suggest that the action of prolactin in the rat prostate is not mediated through the action of androgen.

Animals↗
PubMed1983

Histochemical and biochemical characteristics of the transient hypertrophy of the denervated rat hemidiaphragm.

A systematic study of the different fiber types of rat diaphragm muscle in the first 10 days after unilateral denervation showed approximately a 10% decrease in diameter of the white fibers, 25% increase in that of intermediate fibers, and 35% increase in that of red fibers together with diminished differential staining properties both for myosin ATPase and Sudan black. There was also a doubling of the amount of connective tissue. A reduction in total lipid concentration of the tissue included decreases in both triacylglycerol and phospholipid, but not cholesterol. Magnesium concentration in the tissue also declined, as did activity of Ca2+-activated, though not Mg2+-activated, myosin ATPase.

Adenosine Triphosphatases↗
PubMed1981

Cyclic nucleotides in the denervated rat diaphragm and the effect of cyclic AMP on ornithine and adenosylmethionine decarboxylases.

The concentrations of cyclic AMP and cyclic GMP were measured in the denervated rat diaphragm at various times following unilateral phrenicectomy. Cyclic AMP concentration was raised by the second day after operation, reached a peak by the third day, followed by another increase at around 10 days. By contrast, cyclic GMP concentration was decreased within a day after denervation and remained below control levels at all subsequent times studied. Epinephrine in vitro produced a comparable increase in the concentration of cyclic AMP in both normal and denervated tissue. The concentration of adenosine appeared unchanged in the denervated diaphragm by comparison with its innervated control. Activity of ornithine decarboxylase was elevated in the diaphragms of rats treated with dibutyryl cyclic AMP, but this effect could also be achieved with sodium butyrate alone. Adenosylmethionine decarboxylase activity, was unaffected after treatment with either compound. These observations and others discussed are taken to indicate a lack of direct relationship between cyclic AMP concentrations and the activity of the rate-limiting enzymes of polyamine biosynthesis in the rat diaphragm.

Adenosylmethionine Decarboxylase↗
PubMed1981

The influence of nerve section on the metabolism of polyamines in rat diaphragm muscle.

Concentrations of spermidine, spermine and putrescine have been measured in rat diaphragm muscle after unilateral nerve section. The concentration of putrescine increased approx. 10-fold 2 days after nerve section, that of spermidine about 3-fold by day 3, whereas an increase in the concentration of spermine was only observed after 7-10 days. It was not possible to show enhanced uptake of either exogenous putrescine or spermidine by the isolated tissue during the hypertrophy. Consistent with the accumulation of putrescine, activity of ornithine decarboxylase increased within 1 day of nerve section, was maximally elevated by the second day and then declined. Synthesis of spermidine from [14C]putrescine and either methionine or S-adenosylmethionine bt diaphragm cytosol rose within 1 day of nerve section, but by day 3 had returned to normal or below normal values. Activity of adenosylmethionine decarboxylase similarly increased within 1 day of nerve section, but by day 3 had declined to below normal values. Activity of methionine adenosyltransferase was elevated throughout the period studied. The concentration of S-adenosylmethionine was likewise enhanced during hypertrophy. Administration of methylglyoxal bis(guanylhydrazone) produced a marked increase in adenosylmethionine decarboxylase activity and a large increase in putrescine concentration, but did not prevent the rise in spermidine concentration produced by denervation. Possible regulatory mechanisms of polyamine metabolism consistent with the observations are discussed.

Adenosylmethionine Decarboxylase↗
PubMed1979

Mutant of B-tropic murine leukemia virus synthesizing an altered polymerase molecule.

A nonconditional mutant of B-tropic murine leukemia virus (MuLV), defective in polymerase, has been isolated by cloning chronically infected cells. The cell clone containing the mutant produced virus particles which were noninfectious. However, superinfection of the cells by replication-competent XC-negative viruses resulted in the rescue of virus capable of forming plaques in a modified XC test, termed the "complementation plaque assay" (A. Rein and R. H. Bassin, J. Virol. 28:656-660, 1978). Analysis of the noninfectious virions produced without superinfection demonstrated that they contained only 2 to 5% of the wild-type level of reverse transcriptase activity. Purification of this activity indicated that it was associated with a smaller molecule than that produced by wild-type virus. Cells producing the mutant virions did not contain the gag-pol precursor, Pr180gag-pol; however the cells contained proteins of 147K and 114K daltons precipitable with anti-pol serum. All of the normal structural proteins as well as 70S genomic RNA could be detected in the mutant particles. An interference test indicated that a functional ecotropic glycoprotein was synthesized by the mutant. These results indicate that the mutant has a unique defect in the pol gene.

Animals↗
PubMed1972

Tapetoretinal degeneration in childhood presenting as a disturbance of behaviour.

Four children presented at the age of 6 years with progressive disturbances of behaviour due to increasing visual handicap. In three of them routine ophthalmological examination was carried out in the early stages, but no objective evidence of eye disease was found. The severity and nature of the visual defect and its causal relationship to the behaviour disorder went unrecognized for periods ranging from 18 to 30 months. Eventually the development of retinal changes enabled a diagnosis of tapetoretinal degeneration to be made which was confirmed by the finding of extinction of the electroretinographic response. Transfer of the children to schools for the visually handicapped resulted in improvement in their behaviour disorder.Electroretinography is of great importance in the early diagnosis of juvenile tapetoretinal degeneration.

Anesthesia, General↗