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Biomedical subjects

D Stewart

Publications and source records attributed to D Stewart.

At least 253 records · Page 14Linked to original sources

Species identification and antibiotic susceptibility testing of enterococci isolated from hospitalized patients.

A total of 236 enterococci from hospitalized patients were identified to the species level, and their susceptibilities to 11 antibiotics were determined. Overall, 195 (82.6%) and 38 (16.1%) isolates were identified as Enterococcus faecalis and E. faecium, respectively, but the species distribution as determined from blood culture isolates differed markedly. A total of 27 (63.2%) E. faecium isolates, but no E. faecalis strains, were ampicillin resistant (MIC, greater than 8 micrograms/ml). High-level gentamicin resistance (MIC, greater than 500 micrograms/ml) was found in 8.2% of E. faecalis isolates but was not seen in other species.

Ampicillin Resistance↗

Dose-dependent effect of cyclosporin on renal arterial resistance in dogs.

Important side effects of cyclosporin (CSA) are renal insufficiency and hypertension. They might be related to a renal vasoconstrictive effect of CSA, and this vascular response might be due to a local mechanism. CSA was injected in isolated renal artery perfused at constant flow in dogs. Changes in renal perfusion pressure reflected variations in vascular resistance. Pure CSA was dissolved in autologous blood and injected at doses of 0.5, 1, 5, and 10 mg. The infusion of 0.5 and 1 mg caused averaged renal perfusion pressure increases of 8 +/- 4 mmHg and 15 +/- 8 mmHg. Renal venous CSA levels averaged 32 +/- 3 and 49 +/- 9 nmol/l, respectively, at the end of injections. Infusion of 5 and 10 mg of CSA caused averaged renal perfusion pressure increases of 32 +/- 12 mmHg and 81 +/- 21 mmHg. Renal venous CSA levels at the end of injections averaged 142 +/- 30 and 382 +/- 82 nmol/l, respectively. A positive correlation was found between the changes in renal perfusion pressure and renal venous CSA levels. Blockade of alpha-adrenergic receptors, surgical renal sympathectomy, administration of thromboxane receptor antagonist, and endothelial-dependent vasodilation by acetylcholine infusion did not affect the renal vasoconstriction effect of CSA; renal response to CSA was prevented by blockade of the Ca channels with diltiazem, and the plasma endothelin concentration in renal venous blood increased significantly after injection of CSA. A dose-dependent increase in renal arterial resistance occurs with therapeutic blood levels of CSA. Renal vasoconstriction is induced by a local effect at the arterial wall, which is independent of neurogenic, adrenergic, and prostaglandin mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Catheter-induced tricuspid regurgitation. Incidence and clinical significance.

The incidence and severity of catheter-induced tricuspid regurgitation has not been studied extensively. Given the frequency with which right heart catheters are employed to measure cardiac output, it is important to know whether the severity of catheter-induced tricuspid regurgitation is sufficient to invalidate the measurement of thermodilution cardiac output. Accordingly, the purpose of the present prospective study was to determine the incidence and severity of catheter-induced tricuspid regurgitation in 25 men (mean age, 58.1 +/- 1.4 years) using Doppler ultrasound. The tricuspid valve was interrogated from two orthogonal views using pulsed-wave and color flow Doppler, either in the presence or absence of a 7-French catheter across the tricuspid valve. The severity of catheter-induced tricuspid regurgitation was graded semiquantitatively using a validated scoring system. Pulsed-wave Doppler studies showed that the incidence of catheter-induced tricuspid regurgitation was 48 percent, and that the average tricuspid regurgitation score increased from 0.41 +/- 0.16 to 0.61 +/- 0.17 (p less than 0.01). Color flow Doppler studies showed similar findings. Further, the incidence of catheter-induced tricuspid regurgitation was not related to the patient's underlying hemodynamic status or right ventricular geometry. In conclusion, this study shows for the first time that the quantitative extent of catheter-induced tricuspid regurgitation is small, and is therefore unlikely to be important clinically, particularly with regard to the assessment of thermodilution cardiac output.

Cardiac Catheterization↗

The defibrillator.

Explore the source record for details and available documents.

Electric Countershock↗

Grampian Health Board's joint drug formulary.

OBJECTIVE: To develop a model for creating a joint general practice-hospital formulary, using the example of ulcer healing drugs. DESIGN: A joint formulary development group produced draft guidelines based on an earlier hospital formulary, which were sent to interested local general practitioners for consultation. Revised guidelines were then drawn up and forwarded to the health board's medicines committee for approval and distribution. SETTING: Grampian Health Board. SUBJECTS: Nine members of joint formulary development group plus local general practitioners who were invited to comment on a list of 11 ulcer healing drugs. MAIN OUTCOME MEASURE: Degree of coincidence of drugs selected by hospital doctors and general practitioners. RESULTS: The ulcer healing drugs selected by the panel of general practitioners and by hospital doctors were highly coincident. The cost of one day's treatment with drugs varied considerably between hospital and general practice--for example, one drug cost 46p in hospital and 1 pounds in general practice and another cost 1.26 pounds in hospital and 1.01 pounds in general practice. Overall, six drugs cost more in hospital and five cost more in general practice. CONCLUSIONS: A joint formulary for use in hospitals and general practice in a health board can be devised fairly simply by consultation as virtually the same drugs are used in both types of practice. It should influence the health board's expenditure on drugs and affect the choice of drugs when a patient is discharged from hospital or is referred to any hospital in the region.

Anti-Ulcer Agents↗

Characterization of a unique tomaymycin-d(CICGAATTCICG)2 adduct containing two drug molecules per duplex by NMR, fluorescence, and molecular modeling studies.

Tomaymycin is a member of the pyrrolo[1,4]benzodiazepine [P(1,4)B] antitumor antibiotic group. This antibiotic is proposed to react with the exocyclic 2-amino group (N2) of guanine to form a covalent adduct that lies snugly within the minor groove of DNA. While DNA-footprinting experiments using methidiumpropyl-EDTA have revealed the favored bonding sequences for tomaymycin and related drugs on DNA, the stereochemistry at the covalent bonding site (C-11) and orientation in the minor groove were not established by these experiments. In previous studies using a combined fluorescence, high-field NMR, and molecular modeling approach, we have shown that for tomaymycin there are two diastereomeric species (11R and 11S) on both calf thymus DNA and d(ATGCAT)2. Although we were able to infer the identity (stereochemistry at C-11 and orientation in the minor groove) of the two species on d(ATGCAT)2 by high-field NMR and fluorescence studies, in combination with molecular mechanics calculations, definitive experimental evidence was lacking. We have designed and synthesized a self-complementary 12-mer [d(CICGAATTCICG)2] based on the Dickerson dodecamer [d(CGCGAATTCGCG)2] that bonds identically two tomaymycin molecules, each having a defined orientation and stereochemistry. Thus the bis(tomaymycin)-12-mer adduct maintains the self-complementarity of the original duplex molecule. Two-dimensional proton J-correlated spectroscopy (COSY) of the bis(tomaymycin)-d(CICGAATTCICG)2 adduct (I = inosine) unequivocally shows that C-11 of tomaymycin covalently bonds through N2 of guanine with an 11S stereochemistry in the sequence 5'-CGA-3'.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibiotics, Antineoplastic↗

Comparative therapeutic efficacy of recombinant interferons-alpha, -beta, and -gamma against alphatogavirus, bunyavirus, flavivirus, and herpesvirus infections.

Recombinant (r) preparations of interferons (IFN)-alpha, -beta, and -gamma were shown to protect mice against experimental virus infections with herpes simplex virus type 2 (HSV-2), and with three RNA-containing viruses from different families: Banzi, a flavivirus; Semliki Forest virus (SFV), an alphatogavirus; and Caraparu, a bunyavirus. The antiviral effects of the three different types of IFN were different with each virus. HSV-2 was the most sensitive virus, followed by SFV. Against Banzi virus, IFN-gamma was only effective when given both before and after infection. Against Caraparu virus, only IFN-gamma had a significant effect. These results suggest that IFN therapy might be valuable in human infections with these viruses, but that the correct choice of IFN and dose regimen is likely to be important.

Alphavirus↗

Sulphoevernan, a polyanionic polysaccharide, and the narcissus lectin potently inhibit human immunodeficiency virus infection by binding to viral envelope protein.

Sulphoevernan is a sulphated alpha-1----3, 1----4 polyglucan (Mr 20,000) with a helical structure. This compound effectively inhibits both human immunodeficiency virus type 1 (HIV-1) and type 2 infection of cells in vitro at concentrations around 0.5 micrograms/ml. Moreover, the compound completely inhibits HIV-1-induced syncytium formation at a concentration of 1 microgram/ml. Competition experiments with 35S-labelled sulphoevernan revealed that the mannose-specific lectin from Narcissus pseudonarcissus prevented binding of sulphoevernan to HIV-1, whereas the antibody OKT4A did not reduce the amount of sulphoevernan bound to MT-2 cells. These data indicate that the non-cytotoxic polymer sulphoevernan binds to the virus rather than to the host cell. In vivo studies, using Rauscher leukaemia virus in NMRI mice, revealed that, at a daily dose of 20 mg/kg, the animals were protected against virus-induced increases in spleen weight. From these in vitro and in vivo data we conclude that sulphoevernan has potential in the treatment of acquired immunodeficiency syndrome.

Antiviral Agents↗

Three cases of partial trisomy 7q owing to rare structural rearrangements of chromosome 7.

Three cases of partial trisomy 7q are described. One case had duplication of region 7q22.1----q31.2 owing to a de novo direct intra-arm intrachromosomal duplication. The other two cases, first cousins, were trisomic for 7q34----qter, resulting from recombination within the inserted segment of a dir ins(7;17)(q34;q23.1q25.3)mat. All three cases had a number of the already recorded manifestations of partial trisomy 7q, namely strabismus, low set ears, depressed nasal bridge, small nose, hypotonia, and mental retardation.

Adult↗

Application of the guidelines for client-centred practice to paediatric occupational therapy.

This paper outlines the process of incorporating the "Guidelines For the Client-Centred Practice of Occupational Therapy" into the practice of occupational therapy in an out-patient rehabilitation facility serving young people with physical disabilities. Specifically, the areas of practice addressed are screening and assessment. The process started in 1987 with an identification of the need to find a holistic framework that meets the complex needs of clients with chronic physical disabilities. The conceptual model of occupational performance, as outlined in the Guidelines, provided such a framework. The process of incorporating the Guidelines into the screening and assessment practices of occupational therapists at Erinoak Serving Young People With Physical Disabilities is described, with examples of documents developed by the department. Suggestions are given to integrate the conceptual model of occupational performance into the practice of occupational therapists working with children and adolescents with physical disabilities.

Adolescent↗

Sequential methotrexate, 5-fluorouracil, and leucovorin in metastatic measurable colorectal cancer. Does it work?

Four single-arm trials using methotrexate (M), 5-fluorouracil (5FU), and leucovorin (L) were sequentially performed in metastatic measurable colorectal cancer using different dosing and timing schedules for the three drugs. A total of 99 patients were entered into the trials, 92 (49 men and 43 women) of whom were evaluable for response. Although the first trial appeared to have a 36% response rate, the overall response rate seen in the four trials was not higher than historical reports of 5FU alone. We could find no correlation with dose intensity or patient characteristics to account for the apparent good results of the first trial. It is our conclusion that MFL is not an active combination in colorectal cancer. After progressing to the fourth trial, four patients were placed on 5FU alone (supported by a grant from Lederle, Canada). This resulted in one response in a patient who had not responded to the three-drug combination and stable disease in two patients previously progressing. Although there are many reports of this combination working, the possibility is raised that M may be inhibitory to the combination despite the in vitro data.

Antineoplastic Combined Chemotherapy Protocols↗

A phase II study of ifosfamide, cisplatin, etoposide in patients with advanced non-small cell lung cancer: a preliminary report.

Twenty previously untreated patients with histologically or cytologically proven non-small cell lung cancer (NSCLC) were treated with ifosfamide in combination with cisplatin and etoposide. Patients received ifosfamide 4 g/m2 with mesna uroprotection on day 1 and cisplatin 25 mg/m2 and etoposide 100 mg/m2 on days 1 through 3. Courses were repeated every 28 days. Premedication with prochlorperazine, dexamethasone, and high-dose metoclopramide was given to prevent nausea, and lorazepam was added on days 2 and 3 only. Seventeen male and three female patients (median age, 57 years) have been treated. Two patients had stage IIIb disease, and 18 had hematogenous metastases. Eighteen patients are evaluable for response and toxicity, and it is too early to evaluate two patients. Early in the study, two patients died of toxicity and have been classified as nonresponders. One patient achieved complete response (21+ weeks), and seven patients achieved partial response (median, 30+ weeks; range, 5 to 38+), for an overall response rate of 44.5%. The median survival of the group has not been reached, and 14 patients are alive 5 to 38+ weeks from the start of treatment. The median nadir granulocyte count was 0.275 x 10(9)/L (range, 0 to 2.283 x 10(9)/L), and there were six episodes (involving 5 patients) of neutropenia-associated fever, one of which resulted in death. The median nadir platelet count was 120 x 10(9)/L (range, 13 to 385 x 10(9)/L), but no patient experienced bleeding or required platelet transfusions. Five patients required RBC transfusions. Only eight patients had grade 2 gastrointestinal toxicity, and one patient had microscopic hematuria; there was no CNS toxicity.

Adult↗

Recovery of functional human lymphocytes from Leukotrap filters.

We report here a method by which functional human PBL may be recovered from a blood product preparation unit (Leukotrap) which is normally employed by blood banks to prepare a leukocyte-poor blood product and which is commonly discarded after use. Blood filters which were back-flushed with cold, phosphate-buffered saline (PBS) and the resulting buffy coats collected and separated on Histopaque gradients yielded an average of 2.67 x 10(8) (+/- 1.17 x 10(8] cells per filter processed (n = 38), with viability greater than 95%. The percentages of cell types recovered before or after Histopaque separation closely approximated those reported for freshly drawn blood when examined using differential staining and morphological criteria. Fluorescent antibody analysis revealed a normal distribution of Leu-4 (T), Leu-12 (B), Leu-3a (T helper), Leu-2a (T suppressor) and Leu-M3 (macrophage) positive cell subsets. Recovered lymphocytes were fully responsive to phytohemagglutinin (PHA), concanavalin A (ConA) and pokeweed (PWM) mitogens. Random donor lymphocytes which were co-cultured in a two-way mixed lymphocyte response (MLR) were fully capable of proliferative responses compared to the same populations cultured alone. The results from our study indicate that Leukotrap filters provide a readily available, easily processed and convenient source of functional human PBL for use in the in vitro study of the human immune system.

Cell Separation↗