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Biomedical subjects

A M Clarke

Publications and source records attributed to A M Clarke.

At least 37 records · Page 2Linked to original sources
PubMed1993

Comparative in vitro activity of biapenem, a new carbapenem antibiotic.

Biapenem is a new carbapenem antibiotic with high stability to human renal dehydropeptidase I. Its in vitro activity was compared with that of imipenem, meropenem, ceftazidime, ceftriaxone, piperacillin and gentamicin against a total of 650 recent clinical isolates. MICs were determined by a standard agar dilution procedure and all isolates were tested at two inocula (10(4) and 10(6) cfu). Biapenem inhibited 90% of isolates of Escherichia coli, Klebsiella spp., Proteus mirabilis, Proteus vulgaris, Morganella morganii, Providencia stuartii, Enterobacter spp., Citrobacter freundii, Serratia marcescens, Salmonella typhi, Shigella sonnei and Yersinia enterocolitica at < or = 2 mg/l and was as active as or two- to four-fold more active than imipenem against all these species, with the exception of Serratia marcescens, against which imipenem was two-fold more active. Biapenem was two-fold more active than imipenem against Pseudomonas aeruginosa (MIC90 4 mg/l) and had activity similar to that of imipenem against the Bacteroides fragilis group (MIC90 0.5 mg/l) but was two-fold less active than imipenem against methicillin-susceptible Staphylococcus aureus (MIC90 0.06 mg/l) and was, like imipenem, inactive against methicillin-resistant Staphylococcus aureus.

Anti-Bacterial Agents↗
PubMed1993

Prediction of the outcome 24 hours after carpal tunnel decompression.

A prospective study has been performed on 47 wrists treated by surgical decompression for carpal tunnel syndrome. In all cases where there was symptomatic relief within the first 24 hours postoperatively, a good or excellent outcome was obtained when the patients were reviewed six weeks after surgery. If subjective improvement was not obtained by 24 hours, a good outcome was still possible but a poor outcome became more likely.

Adolescent↗
PubMed1993

Role of the surgical position in the development of postoperative low back pain.

The aetiology of postoperative back pain is contentious. Although the role of the surgical position has not been fully established, the lithotomy position is often implicated. In order to investigate this common surgical complication further, a prospective study has been performed on 101 hysterectomy patients. The supine (52 patients) and the lithotomy (49 patients) positions have been compared and contrasted within this series. Ten patients in the supine group (20%) and seven patients in the lithotomy group (14%) developed postoperative low back pain (p > 0.1). The mean duration of symptoms postoperatively for the whole series was 7 months. We conclude that postoperative backache is an under-estimated complication of surgery and that this problem occurs equally whether the supine or the lithotomy positions are used.

Adult↗
PubMed1993

Combined proliferating cell nuclear antigen and morphometric analysis in the diagnosis of cutaneous lymphoid infiltrates.

AIMS: To evaluate the use of morphometry in the diagnosis of benign and malignant cutaneous lymphoid infiltrates; and to determine whether the sensitivity of detection of cutaneous T cell lymphoma (CTCL) could be improved by selectively measuring cells expressing proliferating cell nuclear antigen (PCNA). METHODS: 44 archival biopsy specimens were studied. These included cases of CTCL, non-specific chronic dermatitis, lichen planus and lupus erythematosus. PCNA was identified using a standard immunohistological technique. Reactive cells were identified using automatic colour discrimination, and the size and shape were determined interactively. Similar measurements were made on the total dermal lymphocyte population. RESULTS: There was no significant difference between the proportions of PCNA reactive cells in any of the diseases studied. The PCNA positive lymphocytes in CTCL were larger than those in lupus erythematosus and lichen planus and were more irregular in shape than those in chronic dermatitis. Differences were also seen in the total lymphocyte population. Plotting cell size and shape(fcircle) for PCNA cells together allowed CTCL to be differentiated from the inflammatory disorders with a sensitivity of 80% and a specificity of 93%. This was better than could be achieved using measurements made on the total cell population. CONCLUSIONS: This technique can be partly automated and could be useful in the differential diagnosis of cutaneous lymphoid infiltrates. The result are also of some interest in the further understanding of patterns of cell proliferation in skin associated lymphoid tissue.

Antigens, Neoplasm↗
PubMed1993

Global positioning system. New directions in ground/air communications.

The use of helicopters for on-scene emergency response has become an important part of the EMS system. In fact, air transport of advanced-level personnel to the scene of accidents and the rapid transport of patients to acute-care facilities frequently have been lifesaving.

Air Ambulances↗
PubMed1993

Closed intramedullary biopsy for metastatic disease.

The surgical stabilization of metastatic fractures or impending fractures of long bones is recommended with the use of intramedullary nails. While the primary tumour has often been diagnosed previously, there are occasions when the fracture may be the presenting feature of malignancy. In both circumstances surgical oncologists require a histological diagnosis from around the fracture site so that any adjuvant therapy can be planned. Open biopsy is often employed although a closed method has been used by percutaneous puncture. Although intramedullary specimens have been obtained before with long bronchial type biopsy forceps, we report a simple and reliable technique for closed biopsy taken from intramedullary reamings at the time of fracture fixation. Lesions from both the femur and the humerus are amenable to this technique.

Aged↗
PubMed1993

A modified neural network model of tumor cell interactions and subpopulation dynamics.

Tumors consist of phenotypically heterogeneous subpopulations of cells which are frequently affected by both autocrine and paracrine factors. Applying concepts from neural network theory, we have developed a computer model of chemical communication among hypothetical tumor cells, which simulates some of the complex epigenetic behavior of real tumors. Deletion of subpopulations often destabilized the whole population. The impact of deletion of specific subpopulations was affected by (a) which subpopulation was deleted, and (b) the timing of the deletion during tumor progression.

Cell Communication↗
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↗