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Biomedical subjects

C Dixon

Publications and source records attributed to C Dixon.

10 recordsLinked to original sources
PubMed1992

Another view to blood and body substance precaution: 1988-91.

Occupational transmission of human immunodeficiency virus (HIV) in hospitals can be prevented with the use of 'blood and body substance precaution'. At the Royal Victoria Hospital, an infection control objective is to get employees automatically to use blood and body substance precaution with all patients--without relying on isolation signs. The concept of blood and body substance precaution was introduced in 1988 and simultaneously used with disease-specific signs. It was observed that disease-specific signs were mostly used to identify HIV-positive patients; this was verified under documented surveillance from July 7 to August 8, 1990, when 60 patients (14 HIV-positive and 46 whose HIV etiology was unknown) were observed. All 14 known HIV-positive patients were isolated with signs, while only four of 46 unknown HIV-positive patients (8.6%) had signs. The views of individual employees were subsequently studied via a questionnaire and results from this survey showed there was preference for isolating HIV-positive patients and identifying them with a sign.

Attitude of Health Personnel↗
PubMed1990

Pyoderma gangrenosum presenting as Fournier's gangrene.

We report a case of pyoderma gangrenosum presenting as Fournier's gangrene. Although both processes have a similar presentation effective management is markedly different. Whereas broad-spectrum antibiotics and aggressive surgical débridement are necessary to control Fournier's gangrene, immediate institution of corticosteroids and local wound care are indicated for pyoderma gangrenosum.

Adult↗
PubMed1986

Biosynthesis of nuclear proteins after stimulation of quiescent Swiss mouse 3T3 cells.

Stimulation of quiescent Swiss mouse 3T3 fibroblasts either by serum or by the low molecular weight hormones, prostaglandin F2 alpha and insulin, induces DNA synthesis after a lag period of about 15 h. Following restimulation by serum or these pure hormones there is an overall increase of two- to fourfold in the rate of biosynthesis of nuclear proteins. In addition, there is a relative decrease in some proteins (Mr = 200 X 10(3), pI 6.0-6.5), while others increase (e.g. actin). Two polypeptides show specific correlations with the exit from G0. The synthesis of p30 (Mr = 30 X 10(3), pI 5.2) is at a maximum within 5 h of restimulation, while the synthesis of p36 (Mr = 36 X 10(3), pI = 4.25) is first seen at 10-20 h after restimulation. Synthesis of p36 correlates well with the initiation of DNA synthesis. The synthesis of both proteins is stimulated by serum and by the hormones. Thus there are common biosynthetic responses to different stimuli indicating convergent pathways leading to DNA biosynthesis. Addition of hydrocortisone with the growth-stimulatory hormones inhibits both entry into the S phase and biosynthesis of p36. In contrast, hydrocortisone does not alter the biosynthesis of p30. This 'early' protein, p30, is different from the products of both c-fos and c-myc. Therefore, we have identified two specific components that might participate in the regulation of cell proliferation.

Animals↗
PubMed1985

Increased bronchial responsiveness caused by ingestion of ice.

We studied 7 asthmatics who had a history of symptoms exacerbated by ice-cold drinks. Bronchial responsiveness to inhaled histamine was measured before and after ingestion of 40 ml of ice or water at room temperature. Although there was no change in baseline peak flow, a significant increase in bronchial responsiveness to histamine developed by 90 min after the ingestion of ice. No satisfactory explanation could be found.

Adolescent↗
PubMed1977

Absorption of amino penicillins from everted rat intestine.

1. Using an in vitro everted gut sac method based on that of Wilson & Wiseman (1954), a number of amino penicillins were tested in order to identify the involvement of any specialized transport mechanisms in their absorption across rat intestine. 2. Only one of the amino penicillins, cyclacillin (1-amino-cyclohexyl penicillin) was shown to be actively transported. The other penicillins appeared to diffuse passively across the intestine. 3. Cyclacillin was found to concentrate against a gradient at 37 degrees C but not at 19 degrees C. 4. Transport of cyclacillin across the mucosal membrane was saturated at mucosal concentrations greater than 1000 microgram/ml. 5. The rate of the forward flux of cyclacillin was many times that of its back flux. 6. No relationship between the active transport of cyclacillin and that of amino acids could be demonstrated.

Amoxicillin↗
PubMed1977

The protective action of zinc against the deleterious effects of cadmium in the regenerating forelimb of the adult newt, Notophthalmus viridescens.

Forelimbs of adult male newts (Notophthalmus viridescens) were amputated and immediately dipped in cadmium nitrate for 2 minutes; in addition, some of the newts were injected with zinc chloride 24 hours prior to, or 24 hours after amputation. Dipping the amputated forelimb of a newt in a solution of 0.4 M cadmium nitrate completely inhibited or retarded regeneration throughout the 65 days of observation. Other effects of cadmium administration included erythema of the limb, an extensive protrusion of the humerus, and in some cases atypical differentiation of regenerates. When zinc chloride was injected (0.04 mg/g of body weight) intraperitoneally into the newt 24 hours prior to limb amputation and cadmium dipping, the deleterious effects of cadmium treatment were prevented and normal regeneration occurred. When zinc chloride was administered 24 hours after amputation and cadmium dipping, it gave no protection against the cadmium. It is suggested that cadmium might inhibit regeneration through the inactivation of zinc metalloenzymes as a result of an exchange of cadmium for zinc. Zinc chloride administered to newts prior to cadmium treatment may prevent the replacement of zinc by cadmium.

Animals↗
PubMed1976

Evaluation of the mutagenicity of compounds of known carcinogenicity, belonging to the benz[a]anthracene, chrysene, and cyclopenta[a]phenanthrene series, using Ames's test.

Fifty-four polycyclic compounds, 29 of the cyclopenta[a]phenanthrene series, 11 chrysenes, and 14 benz[a]anthracenes, have been tested for mutagenicity by Ames's method, using Salmonella typhimurium TA100. Without exception all 37 carcinogens and a known initiator were mutagens. Of the 16 noncarcinogens 7 were mutagenic, but none of these has yet been tested for initiating, as opposed to carcinogenic, activity. There appeared to be little quantitative correspondence between carcinogenic and mutagenic potency, however, and possible reasons for this are discussed. The aryl hydrocarbon hydroxylase inhibitor 7,8-benzoflavone strongly inhibited the mutagenicity of certain compounds when it was added to the incubations.

Animals↗