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Biomedical subjects

A M Clarke

Publications and source records attributed to A M Clarke.

At least 19 recordsLinked to original sources
PubMed1992

Reconstituted thiopentone retains its alkalinity without bacterial contamination for up to four weeks.

The manufacturers of thiopentone recommend that after reconstitution, it should be kept only for 24 hr to reduce the risk of contamination. However, there are no studies to support this practice and compliance with this recommendation has economic implications. The reasons for discarding a reconstituted bottle of thiopentone are related to concerns about chemical and physical (pH) stability, contamination with infectious agents, and contamination with cellular material. We studied the incidence of bacterial contamination and pH stability of thiopentone in clinical use, as well as the pH stability of thiopentone not in clinical use, and surveyed the eight hospitals affiliated with the University of British Columbia to determine their protocols for thiopental preparation and storage. Cost comparisons were made between our current practice of discarding thiopentone when depleted and the practice of routinely discarding it 24 hr after reconstitution. Samples of thiopentone in clinical use were cultured daily and the pH was measured. The bottles had been in clinical use from 1 to 25 days (mean 4.23 +/- 4.32 SD). Of 106 samples there were no positive bacteriological cultures and there were only minor changes in pH. The telephone survey of the eight hospitals revealed that only one had a policy to discard thiopentone after 24 hr. Cost comparisons indicate that discarding thiopentone 24 hr after reconstitution would result in increased cost. In conclusion, reconstituted thiopentone retains its alkalinity for up to four weeks, and has an acceptably low risk of bacterial contamination for periods beyond 24 hr, therefore thiopentone need not be discarded after 24 hr.

Alkalies↗
PubMed1992

Does plaster immobilization predispose to pulmonary embolism?

Over a 5-year study period, 22 patients with isolated lower limb injuries who were immobilized in a plaster cast developed a pulmonary embolus. This information was not available from orthopaedic audit. Better cross-specialty accounting is required if complications that span different hospital specialties are to be fully elucidated. This problem was heightened by the number of emboli occurring while the patient was being treated as an outpatient.

Adult↗
PubMed1992

Antimicrobial susceptibilities and beta-lactamase characterization of Capnocytophaga species.

Capnocytophaga species have been associated with a wide variety of infections in both immunocompetent and immunocompromised patients. On the basis of data from antimicrobial susceptibility studies, beta-lactam antibiotics have been considered efficacious therapy. Six of 19 isolates from primarily clinical sources across Canada demonstrated beta-lactamase production, and agar dilution susceptibility testing showed broad resistance to beta-lactam antibiotics. For the beta-lactamase producing isolates, clavulanate reduced the MIC of amoxicillin for 90% of the strains tested by 64-fold. Isolates were highly susceptible to clindamycin, imipenem, and ciprofloxacin. Characterization of the beta-lactamases produced by two of these isolates (Van1 and Van2) was performed. Isoelectric focusing revealed an identical isoelectric point of 5.6 for both enzymes, but they had markedly different relative hydrolysis efficiencies, and different conditions were required to extract the enzymes. This study demonstrates the production of different types of beta-lactamases by Capnocytophaga spp. and suggests the need to screen all clinical isolates of Capnocytophaga spp. for the presence of beta-lactamases.

Anti-Bacterial Agents↗
PubMed1992

Chronic microsporidian infection of the nasal mucosae, sinuses and conjunctivae in HIV disease.

A case of chronic infection of the nasal mucosae, sinuses and conjunctivae with a microsporidian parasite in association with HIV infection and immune deficiency is reported. This microsporidian resembles both Encephalitozoon cuniculi and the newly described Encephalitozoon hellem by electron microscopy. This occurred in an adult male resident in the UK with no history of foreign travel. Although there are previous descriptions of conjunctival infections from the USA, this is the first description of infection of the nasal epithelium. Further studies are underway to classify this protozoan.

Adult↗
PubMed1992

Blood loss and transfusion requirements in total joint arthroplasty.

We report a prospective trial of 100 consecutive patients undergoing primary total hip or knee arthroplasty in order to assess their blood transfusion requirements amid recent fears of the transmission of viruses, particularly hepatitis C, from donor to recipient. Of the patients, 84% were transfused one or more units of blood in the perioperative period and the mean percentage blood loss per replacement represented 30% or less of their estimated circulating blood volume. We suggest that with preoperative blood volume calculations and haemoglobin concentrations, a more cautious approach to blood transfusion should be employed when other blood volume expanders would suffice. We believe, firstly, that where blood losses of 30% or less of the blood volume occur, blood transfusion is not always required in patients with high haemoglobin concentrations and large blood volumes. Secondly, cross-matching should be undertaken according to the individual patient's estimated needs, rather than to a group as a whole.

Adult↗
PubMed1992

Therapeutic interchange of cefazolin with metronidazole for cefoxitin.

The effects on patient outcome and drug therapy costs of a therapeutic interchange program using a cefazolin and metronidazole combination in place of cefoxitin were studied. A therapeutic interchange program was initiated in which the pharmacy department automatically replaced orders for cefoxitin with orders for a cefazolin and metronidazole combination. Data were compared for 100 consecutive patients who received cefoxitin before initiation of the program and the first 100 patients who received cefazolin and metronidazole as part of the program. The impact of the program on therapeutic efficacy, adverse effects associated with therapy, and drug therapy costs was assessed. The two patient groups were similar in age, gender, and white blood cell count. The failure rates for treatment or prophylaxis of infection did not significantly differ between the groups. Duration of therapy and incidence of adverse effects did not significantly differ between the groups. The average cost saving was +72 per patient for treatment with cefazolin and metronidazole instead of cefoxitin. A program for therapeutic interchange of cefazolin and metronidazole in place of cefoxitin demonstrated equivalent efficacy and adverse effects, as well as considerable cost savings.

British Columbia↗
PubMed1992

Management of hip posture in cerebral palsy.

Seating arrangements for cerebral palsy children with total body involvement are often unsatisfactory and can pose considerable problems for the multi-disciplinary team. Hip joints at risk of dislocation must be kept in an abducted position in order to minimize pain. A new wheelchair with a barrel-shaped cylindrical seat has been developed which improves the femoral head location and alleviates pain.

Cerebral Palsy↗
PubMed1991

Species identification and antibiotic resistance patterns of the enterococci.

One hundred and forty isolates were identified using the GPI Card (Vitek Systems) and a conventional biochemical scheme. Agar dilution susceptibility testing was performed and isolates were screened for beta-lactamase production. The GPI Card was accurate in identifying Enterococcus faecalis, but discrepant results were obtained for seven (29.1%) of the 24 non-Enterococcus faecalis isolates. Ampicillin resistance was present in 2.9% of isolates and there were no beta-lactamase producers. There was no vancomycin resistance but 12.1% of isolates showed high-level resistance to gentamicin.

Ampicillin Resistance↗
PubMed1991

In vitro activity of the novel cephalosporin GR69153.

The in vitro activity of GR69153 was compared to that of ceftazidime, ceftriaxone, imipenem and gentamicin against a total of 702 recent clinical isolates. MICs were determined by a standard agar dilution procedure and two inocula (10(4) and 10(8) cfu) were used throughout. GR69153 inhibited 90% of isolates of Escherichia coli, Klebsiella pneumonia and Proteus mirabilis at less than or equal to 0.25 mg/l and 90% of isolates of Pseudomonas aeruginosa at less than or equal to 1 mg/l. Citrobacter freundii (MIC90 16 mg/l), Morganella morganii (MIC90 128 mg/l) and Enterobacter spp. (MIC90 greater than 128 mg/l) were considerably more resistant to GR69153. GR69153 was four-fold more active than ceftazidime against methicillin-sensitive Staphylococcus aureus but was inactive against methicillin-resistant Staphylococcus aureus, Enterococcus faecalis and Bacteroides fragilis group.

Bacteria↗
PubMed1991

Epithelioid angiosarcoma of deep soft tissue: a distinctive tumor readily mistaken for an epithelial neoplasm.

We report eight cases of epithelioid angiosarcoma arising in deep, usually intramuscular soft tissue. All the patients were men (mean age, 58). All the lesions arose in a limb or limb girdle. Cardinal morphologic features were the diffuse, sheetlike growth pattern, with only focally apparent vascular differentiation, and epithelioid tumor cells with a degree of intracytoplasmic vacuolation/lumen formation. Immunohistochemically, all eight cases coexpressed keratin as well as endothelial markers. In three cases, endothelial differentiation was confirmed ultrastructurally. Clinically, deep-seated epithelioid angiosarcomas are high-grade neoplasms that rapidly develop metastases. These findings expand the range of recognized epithelioid endothelial tumors and provide further evidence of keratin expression by such lesions. The presence of intracytoplasmic lumina/vacuoles (sometimes containing red blood cells) combined with the characteristic reticulin pattern and striking positivity for Factor VIII-RAg provide the clearest means of distinction from an epithelial metastasis.

Adult↗
PubMed1991

Serum prostatic acid phosphatase activity and prostate specific antigen when the prostate gland is enlarged.

Serum prostatic acid phosphatase activity and prostate specific antigen levels were measured in the serum of 113 patients undergoing transurethral resection of an enlarged prostate gland, and the results compared with the histological diagnosis. Prostate-specific antigen was found to be the more sensitive indicator of malignancy, but prostatic acid phosphatase was more specific.

Acid Phosphatase↗
PubMed1979

Crisis intervention: an experimental study of the effects of a brief period of counselling on the anxiety of relatives of seriously injured or ill hospital patients.

This study was designed to examine the effects of anxiety levels, as measured by the Gottschalk & Gleser (1969) and the Viney & Westbrook (1976) content analysis scales, of a brief period of supportive counselling of relatives who arrived at a hospital emergency admitting ward with a seriously ill or injured patient. Verbal samples were taken for analysis from the subjects before and after a period of counselling (or a period of no counselling for the control group). The results showed that the initial anxiety levels for subjects in both groups was very high. For both the psychoanalytically oriented Gottschalk & Gleser anxiety scale and the Viney & Westbrook scale of cognitive anxiety there was a decrease in the level of anxiety for the counselled group compared with the non-counselled group. The results showed that such crisis intervention in hospitals for relatives who accompany patients to the hospital can reduce their very high levels of diffuse and generalized anxiety.

Adolescent↗