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Biomedical subjects

M Stevens

Publications and source records attributed to M Stevens.

At least 163 records · Page 9Linked to original sources
PubMed1989

Screening urines for bacteriuria.

The examination of urine for the presence or absence of significant numbers of bacteria is a major component of the workload of clinical microbiology laboratories. Many attempts have been made at designing systems to screen urine samples rapidly and automatically; however, none has achieved general acceptance. A system is required which will provide acceptable performance criteria, be compatible with subsequent laboratory procedures, and be cost effective.

Bacteriological Techniques↗
PubMed1988

Outcome of children with hematologic malignancy who are admitted to an intensive care unit.

Sixty-four (48%) of 133 children with hematologic malignancy who were admitted to three pediatric ICUs died. Children who required management because of airway obstruction or after general anesthesia had the best outlook (mortality rate of 7% or less); those children who required major circulatory support or mechanical ventilation for hypoxemia did poorly (mortality rate of 84% or greater). Certain conditions in children with hematologic malignancy that require intensive care are associated with a mortality rate of approximately 75%. These include the following: suspected sepsis, interstitial pneumonitis, encephalopathy due to sepsis or hemorrhage. In children with these life-threatening conditions, therapy must be improved because at this stage, the patients do not benefit from admission to the ICU.

Anemia, Aplastic↗
PubMed1988

Cognitive effects of cranial irradiation in leukaemia: a survey and meta-analysis.

Central nervous system (CNS) prophylaxis involving cranial irradiation has frequently been found to result in cognitive deficits in survivors of childhood acute lymphoblastic leukaemia. The existence of this effect is still controversial, however, as is the question of factors that might affect its severity. The literature is surveyed and a meta-analysis undertaken on 30 IQ comparisons, which shows a substantial average decrement in irradiated subjects. The effect is larger when radiation is administered at a younger age and appears to be progressive. The effect may comprise two elements, one common to young cancer patients and one specific to CNS prophylaxis.

Brain↗
PubMed1988

Severe thrombocytopenia in sickle cell crisis.

Thrombocytopenia is unusual in sickle cell disease. We present the case of a child with homozygous sickle cell disease who experienced life-threatening thrombocytopenia during a prolonged and disabling vasoocclusive episode. Irreversibly sickled cells were conspicuously absent from the peripheral blood at presentation and during the subsequent protracted illness. These observations illustrate the pathophysiology of the intravascular events during vasoocclusive crisis and provide indirect evidence for the consumption of both platelets and irreversibly sickled cells at sites of infarction.

Anemia, Sickle Cell↗
PubMed1987

Control of nephroblastoma: associated hypertension and polydipsia by captopril.

A child with nephroblastoma, severe hypertension, polydipsia, and polyuria is presented. Previous reports of this association describe great difficulty in controlling the hypertension by medical means. Captopril provided prompt and continuing control of this child's hypertension and allowed for optimal preparation prior to surgery.

Captopril↗
PubMed1987

Transplantation of monoclonal antibody-purged autologous bone marrow for treatment of poor risk common acute lymphoblastic leukemia.

Two murine monoclonal antibodies, FMC-8 and WM-21, reactive with the human leucocyte differentiation antigens CD-9 (p-24) and CD-10 (CALLA), respectively, have been used for purging leukemic cells from remission bone marrow. Nine patients with the common variant of acute lymphoblastic leukemia (c-ALL) in second or subsequent remission underwent bone marrow harvesting. Bone marrow mononuclear cells underwent lytic incubation in vitro with antibodies FMC-8 and WM-21, and rabbit serum as a source of complement, and were then cryopreserved. A mean of 0.90 +/- 0.50 x 10(8) nucleated cells per kilogram of recipient body weight remained after treatment, with 0.38 +/- 0.24 x 10(8) nucleated cells and 8.3 +/- 10.3 x 10(4) CFUGM per kg being recovered on thawing. Seven patients subsequently received marrow-ablative treatment with high dose cyclophosphamide (120 mg/kg) and fractionated total body irradiation (12 Gy), followed by infusion of antibody-purged autologous bone marrow. Three deaths due to sepsis occurred within the first 35 days, compounded in one patient by poor marrow engraftment. All other patients engrafted promptly, and four remain in continuous complete remission at 2, 6, 9, and 28 months after transplantation. The procedure carries a substantial risk of early toxicity, but offers a significant chance of prolonged unmaintained remission to selected patients with poor prognosis acute lymphoblastic leukemia.

Adolescent↗
PubMed1987

A comparison of some retrograde and anterograde effects of electroconvulsive shock in patients with severe depression.

Seventy severely depressed patients were randomly assigned to receive either a standard course of bilateral electroconvulsive therapy (ECT) or a course of simulated ECT (muscle relaxant and anaesthesia) identical to the real course except that the shock was omitted. Anterograde amnesia due to the shock was demonstrated in recognition memory for word lists and in recall of labels for faces, but this was eliminated by priming. Retrograde amnesia was also present for labels for faces learned the day before a treatment, but this was not eliminated by priming. Recognition memory for material learned in the remote past was better in the patients who had received shock than in those who had received only anaesthetic.

Adult↗
PubMed1986

Recent trends in breast surgery in the United States and United Kingdom.

Data on breast surgery from national samples of patients discharged from hospital in the United States and in England and Wales were reviewed for the years 1970-80. In the United States the rate of breast surgery increased dramatically in 1974 and 1975, but in Britain it remained constant and well below the level in the United States. In both countries the proportion of radical mastectomies declined and the proportion of less extensive procedures rose. The increase in mastectomy rates in the United States probably resulted from increased public concern about breast cancer and from the promotion of breast screening in the mid-1970s. The costs, morbidity, and early mortality associated with a higher rate of mastectomy are substantial and the advantages unclear.

Age Factors↗
PubMed1986

Beta-adrenergic receptor properties of canine myocardium: effects of chronic myocardial infarction.

To determine the effects of chronic myocardial infarction on beta-adrenergic properties of canine myocardium, the hearts of nine mongrel dogs were studied 3 weeks after acute myocardial infarction. Infarction was produced by ligating the left anterior descending coronary artery in five dogs and the circumflex artery in four dogs. The heart was divided into normal and infarct zones (either anterior or posterior, depending on the vessel ligated) and marginal zones (septal and lateral), each zone being subdivided into epicardial and endocardial portions. Myocardial blood flow (microsphere technique) was markedly reduced in the infarct zone. In eight endocardial infarct samples after left anterior descending ligation, the maximal number (+/- SD) of binding sites assessed by 125I-iodocyanopindolol was 3.9 +/- 1.9 pmol/mg deoxyribonucleic acid (DNA) and was reduced from normal endocardial values (9.7 +/- 9.4 pmol/mg DNA, p less than 0.05). The dissociation constant (Kd), which is a measure of the affinity of the iodinated antagonist for the receptor, did not differ (304 +/- 222 versus 338 +/- 219 pM, p = NS). In the epicardium, the maximal number of beta-adrenergic receptors was also reduced (p less than 0.05), without a change in Kd. In the lateral and septal zones neither the maximal number of binding sites nor Kd values differed from those of normal endocardium. In nine endocardial infarct zones, (-)-isoproterenol-stimulated adenylate cyclase activity was reduced compared with control (34,870 +/- 29,430 versus 88,660 +/- 63,640 pmol/mg DNA/30 minutes, p less than 0.01), but the ratio of (-)-isoproterenol-stimulated to maximal (sodium fluoride-stimulated) adenylate cyclase activity was unchanged between normal and infarct zones.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1986

A collaborative evaluation of a rapid, semi-automated identification system for gram-negative bacilli: the Quantum II BID.

The recently-introduced semi-automated bacterial identification system, the Quantum II BID, is designed to identify fermentative and non-fermentative gram-negative bacilli in 4-5 h. The system was evaluated independently by the two participating laboratories. Inter-laboratory reproducibility was determined by testing 181 strains in each laboratory and found to be 97.8%. A further 893 organisms, comprising 417 fresh clinical isolates and 476 stock cultures, were then tested by the system in the two laboratories. Of the fresh clinical isolates, 95.7% yielded the same result as the comparative system used (API 20E) and 93.1% of the stock strains were assigned to their expected, previously established identity. Overall agreement between the two systems for all strains examined was 94.3%. There was no significant statistical difference between the results obtained in the two laboratories.

Acinetobacter↗
PubMed1986

Rapid identification of gram-negative bacilli from blood cultures.

Blood-culture broths showing macroscopic or radiometric evidence of growth of gram-negative bacilli were examined by a rapid automated bacterial identification system. A differential centrifugation technique was developed to prepare suitable inocula. The identification results obtained were confirmed by the API 20E method, with single colonies of the strains isolated 24 h later. Of 90 organisms tested, seven did not give the same identification by the two systems. With the rapid automated technique a presumptive identification of gram-negative bacilli can be made 24 h earlier than by more conventional methods.

Bacteriological Techniques↗
PubMed1986

Pharmacokinetics and diuretic effect of bumetanide following intravenous and intramuscular administration to horses.

Concentrations of the potent diuretic bumetanide were determined by a sensitive high performance liquid chromatographic procedure in plasma and urine from horses following intravenous and intramuscular administration of a dose rate of 15 micrograms/kg. The elimination half-life was found to be 6.3 min, the volume of distribution at steady state 68 ml/kg and the total plasma clearance 10.9 ml/min/kg. The onset of diuresis occurred within 15 min and diuresis was no longer apparent 1 h after i.v. administration. Given by the intramuscular (i.m.) route, bumetanide was rapidly absorbed; bioavailability was 70-80%. i.m. administration of bumetanide prolonged its plasma half-life (11-27 min) and enhanced and prolonged its diuretic effect.

Animals↗
PubMed1986

Rapid lysostaphin test to differentiate Staphylococcus and Micrococcus species.

A rapid, simple lysostaphin lysis susceptibility test to differentiate the genera Staphylococcus and Micrococcus was evaluated. Of 181 strains from culture collections, 95 of 95 Staphylococcus strains were lysed, and 79 of 79 Micrococcus strains were not lysed. The seven Planococcus strains were resistant. Clinical isolates (890) were tested with lysostaphin and for the ability to produce acid from glycerol in the presence of erythromycin. Overall agreement between the methods was 99.2%. All clinical Micrococcus strains (43) were resistant to lysostaphin, and all clinical Staphylococcus strains (847) were susceptible. Seven of the Staphylococcus strains did not produce acid from glycerol in the presence of erythromycin. This lysostaphin test provides results in 2 h. It is easier to perform than previously described lysostaphin lysis methods. It is also more rapid and accurate than the glycerol-erythromycin test.

Bacteriological Techniques↗