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Biomedical subjects

G A Wilson

Publications and source records attributed to G A Wilson.

At least 73 records · Page 4Linked to original sources
PubMed1986

Stimulatory effect of forskolin on gastric acid secretion in the rat, in vitro and in vivo.

The effect of forskolin, a potent adenylate cyclase activator, was studied on rat gastric acid secretion in vitro and in vivo. In the isolated gastric mucosa, forskolin was 25 and 100 times more potent than histamine and dibutyryl cyclic AMP respectively, with an EC50 of 2 microM and a maximum effect at 8-10 microM. In the lumen-perfused anaesthetised rat, acid secretion in response to a series of bolus i.v. injections of forskolin failed to show dose dependency, despite dose-related hypotensive effects. Secretory responses to i.v. infusions of forskolin were dose-related and were associated with a rise in gastric mucosal blood flow despite marked hypotension. These results indicate that forskolin has a direct secretagogue effect on parietal cells which, under some circumstances may be modified by its other pharmacological actions.

Aniline Compounds↗
PubMed1986

In vivo and in vitro models of demyelinating diseases. XV. Differentiation influences the regulation of coronavirus infection in primary explants of mouse CNS.

Mouse oligodendrocytes and astrocytes, in primary cerebral explant cultures, were infected with JHMV and MHV3 coronaviruses. Contrary to previous findings with neural cells from the rat (S. Beushausen and S. Dales, 1985, Virology 141, 89-101), these agents show no discrimination in the tropism and have the ability to replicate in either type of murine glial cell. Effects of the differentiation inducer dbcAMP on levels of the myelinspecific enzyme 2':3'-cyclic nucleotide-3'-phosphohydrolase (CNPase) activity and virus replication were determined. In the mouse system there was a gradual, continuous elevation of CNPase beyond 30 days whereas in comparable rat cell cultures maximum CNPase enhancement is elicited within 21 days (F. A. McMorris, 1983, J. Neurochem. 41, 506-515). After dbcAMP treatment replication of both coronaviruses was profoundly suppressed in murine oligodendrocytes, consistent with our findings on JHMV replication in treated rat oligodendrocytes. By contrast the replication of JHMV and MHV3 in dbcAMP-treated murine astrocytes was influenced only marginally. These findings provide further support for the hypothesis that susceptibility of rodents to CNS infection by coronaviruses is determined, in part, by the age-related maturation process of oligodendrocytes.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗
PubMed1985

Factor invariance and the Life Satisfaction Index.

This investigation of the Life Satisfaction Index (LSI) supports findings by Hoyt and Creech (1983) that indicate Adams' (1969) proposed factor structure is not invariant across groups. Two reduced factor models, proposed by Hoyt and Creech and based on a subset of LSI items, were studied with our sample (two levels each of income and age, N = 791). Our work confirms that the Hoyt and Creech 8-item LSI reveals the more stable factor structure of those examined. In addition, we found that the 8-item index has adequate statistical power to be of benefit to those investigators looking at quantitative differences in life satisfaction, with reasonable assurance that older and/or higher-income individuals are interpreting the items in similar ways.

Aged↗
PubMed1983

Subcutaneous emphysema after extraction of maxillary teeth: report of a case.

Inappropriate use of dental equipment that is powered by highly compressed air may directly lead to the formation of subcutaneous emphysema that involves the fascial planes of the head and neck. The high-speed dental handpiece and the air and water dental syringe are the instruments that are most commonly implicated in the reported cases. The treatment of such cases requires a reassured patient, prophylactic antibiotic coverage, and close postoperative follow-up care. Patients should avoid maneuvers that could increase intraoral pressure. Complete resolution should be expected within one week.

Dental Instruments↗
PubMed1982

Effects of inhibitors of 5-hydroxytryptamine uptake on plasma glucose and their interaction with 5-hydroxytryptophan in producing hypoglycaemia in mice.

The effects of various inhibitors of 5-HT uptake on plasma glucose have been studied in normal and monoamine oxidase inhibitor pretreated mice. Additionally their interaction with 5-hydroxytryptophan (5-HTP) in producing hypoglycaemia was studied. Clomipramine, fenfluramine, fluoxetine, ORG 6582 (dl-8-chloro-11-anti-amino-benzo-(b)-bicyclo[3.3.1]nona-3, 6 alpha(10 alpha)-diene hydrochloride), ORG 6997 (dl-4-exo-amino-8-chloro-benzo-(b)-bicyclo[3.3.1]nona-2-6 alpha(10 alpha)-diene hydrochloride), MK 212 and mazindol did not modify the plasma glucose in normal mice but produced hypoglycaemia in mice pretreated with either nialamide or pargyline. Dexamphetamine did not influence plasma glucose in either normal or monoamine oxidase inhibitor pretreated mice. Each of the above drugs except ORG 6997 but including dexamphetamine augmented the hypoglycaemic effect of 5-HTP in normal mice. These responses did not appear to be mediated by insulin since none of the drugs increased the plasma immunoreactive insulin concentration or augmented the hyperinsulinaemic effect of 5-HTP. Moreover, fenfluramine, fluoxetine and ORG 6582 did not augment the hypoglycaemic action of injected insulin although such an augmentation was produced by mazindol.

5-Hydroxytryptophan↗
PubMed1982

The effect of immediate access to a computerized medical record on physician test ordering: a controlled clinical trial in the emergency room.

We performed a randomized clinical trial of the effect of immediately printed summaries of a computerized medical record on physician test ordering rates in an Emergency Room setting. The computerized medical record contained medication history, the results of most diagnostic studies, an outpatient problem list, and inpatient and emergency room diagnoses. Physicians were presented with a printed summary of the patient's computerized record for study but not for control encounters. All other patient information was equally available to both kinds of encounters. All results were provided for one period of the study, designated T1. Due to a program error, summaries were printed without recent data during a period of the study, designated T2. Two-thirds of the visits were cared for by internists, one-third by surgeons. During T1, internists ordered an average of 3.2 tests, costing $34.91 for control visits, and 2.7 tests, costing $29.94 for study control visits (p less than .026). Surgeons also ordered fewer tests during study visits as compared to controls (1.32 vs 1.54) but the differences were not statistically significant. There was no significant effect on either medical or surgical test ordering during time period T2.

Clinical Laboratory Techniques↗
PubMed1982

Survey of North American air carriers regarding protocol for dental identification of in-flight personnel.

A survey of North American air carriers regarding the protocol for dental identification of their in-flight personnel in the event of a disaster was accomplished in July 1980. Initial evaluation of this survey indicates that few air carriers have such a protocol or forensic odontology consultants. Many of the air carriers indicated the need for the development and implementation of such a protocol individualized for their company. Statistical evaluation of the survey is presented with discussion centered on the role of the forensic odontologist consulting with respective air carriers in establishing such protocols. The survey documents areas of need in such protocols.

Accidents, Aviation↗
PubMed1980

Physician response to computer reminders.

A computerized medical record system was designed to detect and remind the responsible clinician about clinical events that might need corrective action. These reminders significantly increased the clinician response rate (in terms of test orders and treatment changes) to the events in question. The addition of relevant medical literature citations to the reminders did not significantly change the clinician response rate as compared with that with reminders alone, nor did it stimulate the physicians to read any of the cited articles kept in an immediately available "library" of reprints.

Clinical Competence↗
PubMed1980

Further studies on the effects of 5-hydroxytryptophan on plasma glucose and insulin in the mouse.

The effects of 5-hydroxytryptophan on plasma concentrations of glucose and immunoreactive insulin were examined in conscious mice. Blood samples were obtained after anaesthetizing the mice lightly with ether at the desired time. Large doses of L-5-hydroxytryptophan (5HTP) (200-400 mg/kg IV) produced a dose-dependent hypoglycaemic response in fasted mice (e.g. control 5.7 +/- 0.2 mmol/l, 5HTP 400 mg/kg 2.6 +/- 0.3 mmol/l). This response was preceded by a significant elevation in the plasma immunoreactive insulin concentration (e.g. control 6 +/- 2 mU/l; 5HTP 400 mg/kg 53 +/- 7 mU/l). Induction of diabetes with alloxan (80 mg/kg IV 72 h previously) prevented the hypoglycaemic effect of 5HTP. Alloxan diabetes abolished the hyperinsulinaemic response to 100 mg/kg of 5HTP and reduced by 66% the response to 400 mg/kg of 5HTP. In alloxan diabetic mice 5HTP produced a marked hyperglycaemic response (control 17.9 +/- 2.0 mmol/l; 5HTP 100 mg/kg 36.1 +/- 2.3 mmol/l). In normal mice pre-treated with nialamide, a monoamine oxidase inhibitor, much lower doses of 5 HTP (5-10 mg/kg) were required to produce hypoglycaemia. There was no detectable elevation in the plasma insulin concentration accompanying the hypoglycaemic response to smaller doses of 5HTP in nialamide treated mice. The hyperinsulinaemic and hypoglycaemic actions of 5HTP in normal mice were prevented completely by pretreatment with benserazide, an inhibitor of aromatic amino acid decarboxylase. 5-hydroxytryptamine did not modify the plasma glucose concentration in either normal or nialamide-treated animals. It is concluded that the hypoglycaemic response to 5HTP in normal mice is mediated at least partly through an elevation in the plasma insulin concentration, although it is likely that additional mechanisms are involved.

5-Hydroxytryptophan↗
PubMed1980

Expression of thymidylate synthetase activity in Bacillus subtilis upon integration of a cloned gene from Escherichia coli.

The gene from Escherichia coli encoding thymidylate synthetase was cloned in the plasmid pBR322. The resulting chimeric plasmid, pER2, was effective in transforming both E. coli and Bacillus subtilis to thymine prototrophy. Uncloned linear E. coli chromosomal DNA was unable to transform thymine-requiring strains of B. subtilis to thymine independence. Linearization of the chimeric plasmid, pER2, with restriction enzymes markedly diminished its ability to transform B. subtilis auxotrophs. The Thy+ transformants derived from the transformation of B. subtilis with pER2 DNA did not contain detectable extrachromosomal DNA as demonstrated by Southern hybridization patterns and centrifugation in CsCl gradients of DNA isolated from B. subtilis colonies transformed with the chimeric plasmid. We conclude that the DNA from the chimeric plasmid was integrated into the chromosome of B. subtilis, demonstrating that extensive homology is not required for the integration of foreign DNA. This is the first reported case of a gene from a Gram-negative bacterium functioning in a Gram-positive organism.

Bacillus subtilis↗
PubMed1980

A study of irradiated bone. III. Scintigraphic and radiographic detection of radiation-induced osteosarcomas.

Within 1 yr after localized irradiation of a hind limb with single (1756 rads) or fractionated (4650 rads in 3 wk) x-ray doses, radiation-induced osteosarcomas were observed in four of nine single-dose rabbits and two of 11 fractionated-dose rabbits. Tumors were observed in the proximal tibia in five cases and the distal femur in one case. In terms of production of osteoid or osseous tissue, three tumors were well differentiated, one slightly differentiated, and two (spindle-cell tumors) undifferentiated. This report summarizes the Tc-99m pyrophosphate (TcPPi) imaging and autoradiographic, radiographic, and histologic studies of these osteosarcomas. The four differentiated osteosarcomas were detected 1--2.5 mo earlier by TcPPi imaging than by radiography, whereas the two undifferentiated tumors were suspected 2 wk or 3.5 mo earlier radiographically. Autoradiograms showed TcPPi localization in bone produced by differentiated osteosarcomas, and in regions of reactive bone resorption and formation peripheral to tumors. The results support a recommendation for combined radiographic and scintigraphic techniques for the early detection of osteosarcomas.

Animals↗
PubMed1980

The predictive value of myocardial radioisotope scanning in animals treated with doxorubicin.

Thirty-four New Zealand white rabbits were treated with doxorubicin and imaged weekly with Tc-99m pyrophosphate to define the value of abnormal myocardial images in predicting doxorubicin-induced cardiac toxicity. Increased myocardial uptake was detected in most animals on sustained treatment with doxorubicin. A greater proportion of the heart was involved with doxorubicin-related histologic changes in animals with strongly positive myocardial images than in treated animals with moderately positive or normal scans. The myocardial images returned to normal levels 2--6 wk after doxorubicin was discontinued. Five of seven rabbits that received doxorubicin after they had three moderately positive myocardial scans, died from congestive heart failure. Three rabbits whose doxorubicin was discontinued because of scan findings, survived for 6 wk or more before dying from renal failure. The three rabbits who received the highest total dose of doxorubicin died of renal failure without developing abnormal myocardial scans.

Animals↗
PubMed1979

The effects of levodopa on plasma glucose in two strains of rat.

The effects of levodopa on plasma glucose were examined in two strains of rats. In fasted Wistar rats levodopa produced a dose-dependent hyperglycaemic response which was augmented by pretreatment with nialamide. This response in nialamide-treated rats was prevented by pretreatment with phentolamine and converted to a hypoglycaemic response. Phentolamine increased the plasma concentration of immunoreactive insulin (IRI). In phentolamine-pretreated rats levodopa produced a further marked increase in the plasma IRI concentration. It is suggested that the prevention of levodopa hyperglycaemia by phentolamine is due to the marked increase in the plasma IRI concentration produced by pretreatment with phentolamine. Moreover the fall in the plasma glucose concentration produced by levodopa in phentolamine-pretreated rats is likely to be due, at least in part, to the additional increase in the plasma IRI concentration produced by levodopa under these conditions. In contrast, in fasted Sprague-Dawley rats pretreated with nialamide, levodopa produced either no effect on plasma glucose, or in larger doses, a marked hypoglycaemic effect followed by death. This hypoglycaemic effect was accompanied by a decrease in the plasma IRI concentration.

Animals↗
PubMed1979

Accidental hydrofluoric acid burns of the hand.

A case report of accidental hydrofluoric acid burns that involve dermal tissue of the hand is presented. Prompt medical treatment for this accident resulted in minimal disfigurement and minimal paresthesia and disability. Protocols for essential treatment and precautions for personnel working in dental laboratories where hydrofluoric acid is used have been discussed.

Burns, Chemical↗