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Biomedical subjects

K Barnett

Publications and source records attributed to K Barnett.

17 recordsLinked to original sources
PubMed2000

Role of cyclooxygenase-2 in modulating gastric acid secretion in the normal and inflamed rat stomach.

Nonsteroidal anti-inflammatory drugs elevate gastric acid secretion, possibly contributing to their ability to interfere with gastric ulcer healing. Inhibitors of cyclooxygenase-2 have been shown to delay experimental gastric ulcer healing. In the present study, we tested the hypothesis that cyclooxygenase-2-derived prostaglandins modulate gastric acid secretion. Studies were performed in normal rats and in rats with iodoacetamide-induced gastritis. Inflammation in the latter group was confirmed histologically and by a threefold increase in tissue levels of the granulocyte marker myeloperoxidase and was also associated with overexpression of cyclooxygenase-2 in the stomach. Basal acid secretion in both groups of rats was not affected by pretreatment with DuP-697, a selective inhibitor of cyclooxygenase-2. A nonselective cyclooxygenase inhibitor, indomethacin, had no effect on acid secretion in normal rats but caused a doubling of acid secretion in the rats with gastritis. DuP-697 had no effect on pentagastrin-induced secretion in either group of rats. Gastritis itself was associated with significantly increased pentagastrin-induced acid secretion, and this was further increased in rats pretreated with indomethacin. These results suggest that in a setting of gastric inflammation, prostaglandins derived from cyclooxygenase-1, not cyclooxygenase-2, exert inhibitory effects on acid secretion.

Animals↗
PubMed1998

Quantitation of carboxyhaemoglobin in blood: external quality assessment of techniques.

The performance of four dedicated carbon monoxide (CO)-oximeters (AVL, Chiron, IL, Radiometer), spectrophotometry with and without dithionite, spectrophotometry by second derivative, and the Whitehead and Worthington precipitation technique for the measurement of carboxyhaemoglobin in blood was compared by a mean of 136 participants in the United Kingdom National External Quality Assessment Scheme in 21 samples formulated to contain from 4% to 48% carboxyhaemoglobin. The dedicated instruments and spectrophotometry by second derivative were of significantly higher precision than the other techniques, producing fewer measurements rejected as being > 3 standard deviations from the sample mean and having a lower standard deviation for non-rejected measurements. The AVL instrument and spectrophotometry by second derivative had a significant positive bias compared to the other techniques. The Whitehead and Worthington method was of an unacceptably low precision.

Carbon Monoxide Poisoning↗
PubMed1996

External quality assessment of Syva Emit and Abbott TDx II assays for methotrexate in serum.

The Syva Emit and Abbott TDx II kits for determination of methotrexate in serum were compared using data from 14 samples distributed by the United Kingdom National External Quality Assessment Scheme to a mean of 38 European laboratories. For methotrexate concentrations above 0.2 mumol/L, there was no significant difference in the bias or coefficient of variation of measurements between the two techniques. A significantly greater number of measurements by Syva Emit (6.9%) were rejected as outliers > 3 SD from the sample mean compared with Abbott TDx (1.3%). The lower sensitivity of the Syva Emit assay was evident in data reported for samples containing methotrexate concentrations below 0.2 mumol/L.

Antimetabolites, Antineoplastic↗
PubMed1995

External quality assessment of techniques for assay of serum ethanol.

Ethanol was assayed by an average of 200 participants in the UK National External Quality Assessment Scheme, in 26 samples of human serum containing 0.1% fluoride/oxalate and added ethanol from 0.2 to 4.5 g/L. Outliers greater than three standard deviations from the consensus mean for any sample were excluded. Data remaining were grouped by technique and the technique mean and standard deviation calculated. Inter-laboratory variation of 13 technique groups was assessed by the coefficient of variation of measurements and bias from the per cent difference of the technique mean from the target value. Gas chromatography (GC) with packed columns and Sigma alcohol dehydrogenase assay protocols that include a sample deproteinization step, showed better between-laboratory agreement but greater bias. The least variable techniques were headspace analysis with GC-packed columns, Kodak Ektachem, bioMérieux and DuPont aca assays. A significant negative bias was produced by Kodak Ektachem and a positive bias by the Lion alcometer which was the most variable technique.

Alcohol Dehydrogenase↗
PubMed1991

Fluconazole therapy for chronic disseminated candidiasis in patients with leukemia and prior amphotericin B therapy.

OBJECTIVE: To study the efficacy of fluconazole against chronic disseminated candidiasis (hepatosplenic candidiasis) in patients with leukemia in whom amphotericin B treatment had failed. DESIGN: Retrospective analysis of patients with chronic disseminated candidiasis treated with fluconazole on a compassionate investigational new drug protocol. SETTING: Multi-institutional. PATIENTS AND METHODS: Twenty consecutive patients received 100 to 400 mg of fluconazole per day for a median of 30 weeks. All had either failed to respond to treatment with more than 2 g of amphotericin B or had serious amphotericin B-related toxicities. RESULTS: Fourteen of 16 evaluable patients (88%) responded. Responses were observed in seven of nine patients in whom adequate doses of amphotericin B had failed and in all seven patients who had amphotericin B-related toxicities. In 12 patients, cytotoxic chemotherapy was continued without flare of the infection. Fluconazole was well tolerated with rare side effects. Aspergillus superinfection developed in three patients and contributed to the death of two of them. CONCLUSION: Fluconazole is a safe and effective agent with significant activity against chronic disseminated candidiasis.

Adult↗
PubMed1988

The effects of epithelial cell supernatant on contractions of isolated canine tracheal smooth muscle.

Airway epithelial cells produce mediators that play a role in regulating airway smooth muscle function. This study was designed to examine the effects of epithelial-derived products on contraction of airway smooth muscle. To avoid biochemical and physical changes that may be produced by stripping epithelium from tracheal smooth muscle, we examined the effect of products from pure cultured tracheal epithelial cells on intact dog tracheal smooth muscle. When bradykinin (10(-5) M) was added to dog epithelial cells in culture and the supernatant was added to strips of isolated tracheal smooth muscle, contractile responses to electrical field stimulation were significantly inhibited. Pretreatment of the epithelial cells with indomethacin (5.6 x 10(-6) M) inhibited this effect. Bradykinin placed directly on the canine smooth muscle had no effect on resting tension or on the response to electrical field stimulation. Contractions of the smooth muscle to exogenous acetylcholine were unaffected by supernatants from either indomethacin-treated or untreated cells stimulated with bradykinin (10(-5) M) compared to time controls. We conclude that bradykinin stimulates the release of a cyclooxygenase-dependent inhibitory factor from airway epithelial cells. This factor is likely to be prostaglandin E2, which is generated by the epithelial cells in response to bradykinin stimulation and inhibits smooth muscle contraction induced by electrical field stimulation. Although the mechanism of this inhibition is unknown, the normal response to exogenous acetylcholine is consistent with the hypothesis that prostaglandin E2 acts by inhibiting cholinergic neurotransmitter release at a prejunctional site.

Acetylcholine↗
PubMedDate not supplied

Doing good & doing well.

Leaders cannot make the "business case" for community benefit in the traditional sense of near-term financial returns on investment. The concept of returns must be expanded to encompass more long-term--yet concrete and measurable--benefits that may be accrued both by nonprofit hospitals and local communities. Hospitals can "do well" economically through a more strategic approach to "doing good."

Community Health Planning↗
PubMedDate not supplied

Working together in rural South Dakota: integrating medical and chiropractic primary care.

OBJECTIVE: To describe the practice of chiropractic in South Dakota and to examine the extent to which they provide primary health care services to the rural population. DESIGN: Survey data from 113 (72%) of the 156 licensed chiropractors in South Dakota (1994). RESULTS: Rural DCs view themselves as primary care physicians and make up one third of the total number of rural primary medical and chiropractic physicians in the state. Rural DCs are more professionally cooperative with medical providers than are urban DCs and, as such, offer services more closely related to primary care. A greater portion of rural DCs, compared with urban DCs, offer in-office laboratory facilities for such services as urinalysis and blood work. Both rural and urban DCs treat large numbers of patients with neuromusculoskeletal (NMS) and non-NMS conditions, with rural DCs being more likely to treat patients with non-NMS conditions, especially skin conditions. CONCLUSIONS: Chiropractors are providing a broad scope of health services in South Dakota, especially in rural areas, indicating that DCs serve as important resources to the South Dakota primary health care system. Chiropractors and general practice medical physicians are increasingly complementing each other in the health care delivery system, especially in rural areas of the state. As such, each profession enhances the system's capacity to offer primary care, with DCs offering primarily NMS care. Continuing increase in the number of medical and chiropractic collaborations is consistent with the imperative to include cooperation with other primary care disciplines to improve health care delivery to rural populations.

Chiropractic↗