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Biomedical subjects

A Carswell

Publications and source records attributed to A Carswell.

16 recordsLinked to original sources
PubMed2005

Proton pump inhibitors reduce the bioavailability of dietary vitamin C.

BACKGROUND: The gastric juice concentration of vitamin C is reduced in subjects with elevated intragastric pH. This is probably because of the fact that the vitamin is unstable at non-acidic pH and undergoes irreversible denaturation. AIM: To determine whether elevation of intragastric pH reduces the bioavailability of dietary vitamin C. METHODS: Plasma vitamin C was measured before and after a course of omeprazole 40 mg/day for 4 weeks in 14 Helicobacter pylori positive and 15 H. pylori negative subjects. Dietary intake of vitamin C was measured and intragastric pH monitored. RESULTS: Compared with the H. pylori negative subjects, H. pylori positive subjects had a lower mean daily vitamin C intake (141.7 mg vs. 41.5 mg, P < 0.01) and also lower plasma vitamin C concentration (25.1 microg/mL vs. 17.4 microg/mL, P < 0.0001). After 28 days of 40 mg/day of omeprazole the mean plasma vitamin C level had fallen by 12.3% (P = 0.04). This fall affected both the H. pylori positive and negative subjects. CONCLUSIONS: We have shown that a short course of omeprazole will cause a reduction in the plasma vitamin C level of healthy volunteers. This decrease in plasma vitamin C is independent of dietary intake of the vitamin and indicates reduced bioavailability. The clinical significance of this is unclear but any adverse effects will be most apparent in H. pylori infected subjects who have a low pre-treatment vitamin C status.

Ascorbic Acid↗
PubMed2002

In vitro studies indicate that acid catalysed generation of N-nitrosocompounds from dietary nitrate will be maximal at the gastro-oesophageal junction and cardia.

BACKGROUND: Dietary nitrate increases saliva nitrite levels and swallowed saliva is the main source of nitrite entering the acidic stomach. In acidic gastric juice, this nitrite can generate potentially carcinogenic N-nitrosocompounds. However, ascorbic acid secreted by the gastric mucosa can prevent nitrosation by converting the nitrite to nitric oxide. METHODS: To study the potential for N-nitrosocompound formation in a model simulating salivary nitrite entering the acidic stomach and the ability of ascorbic acid to inhibit the process. Concentrations of ascorbic acid, total vitamin C, nitrite, nitrosomorpholine, oxygen and nitric oxide were monitored during the experiments. RESULTS: The delivery of nitrite into HCl containing thiocyanate resulted in nitrosation of morpholine, with the rate of nitrosation being greatest at pH 2.5. Under anaerobic conditions, ascorbic acid converted the nitrite to nitric oxide and prevented nitrosation. However, in the presence of dissolved air, the ascorbic acid was ineffective at preventing nitrosation. This was due to the nitric oxide combining with oxygen to reform nitrite and this recycling of nitrite depleting the available ascorbic acid. Further studies indicated that the rate of consumption of ascorbic acid by nitrite added to natural human gastric juice (pH 1.5) was extremely rapid with 200 micromol/l nitrite consumed 500 micromol/l ascorbic acid within 10 s. CONCLUSIONS: The rapid consumption of ascorbic acid in acidic gastric juice by nitrite in swallowed saliva indicates that the potential for acid nitrosation will be maximal at the GO junction and cardia where nitrite first encounters acidic gastric juice. The high incidence of mutagenesis and neoplasia at this anatomical location may be due to acid nitrosation arising from dietary nitrate.

Ascorbic Acid↗
PubMed2001

Seniors' decision making about pain management.

BACKGROUND: Musculoskeletal pain is a problem with which many seniors must contend, many on a daily basis. Little is known, however, of the self-care decisions that seniors make regarding the management and control of this pain. These decisions can influence in a significant manner the delivery of health care to seniors and their overall health and well-being. Purpose. The purpose of our exploratory-descriptive study was to investigate seniors' decision making regarding the management and control of musculoskeletal pain by gathering data about the context of decision making, the types of decisions seniors made, their decisional conflict and the resources they used in decision making. METHODS: Focus groups and a mail-back questionnaire were used. Data were gathered in 1997 from a convenience sample of 50 seniors in Canada who experienced musculoskeletal pain of a noteworthy nature. RESULTS: Findings revealed that participants made decisions within a context of ageing and the health and social consequences of advancing age. The types of decisions they made included to ignore their pain and to use distraction. They also used exercise, the application of heat and cold, and medications to manage pain. Decisional conflict was minimal and consultation with family and friends superseded that with professionals. CONCLUSIONS: This study contributed to knowledge of decision making in later life about health matters generally, and the management and control of pain specifically. Findings point to the resourcefulness of seniors with respect to self-care and decision making. Seniors want to make informed decisions. However, they need information about the risks and benefits of decisions.

Aged↗
PubMed2001

Family caregiving in long-term care facilities.

Family caregiving within institutional settings is a neglected area of research In an era of cost containment, more and more is being asked of families of institutionalized persons. This article presents the results of a study designed to investigate family caregiving following the admission of an elderly relative to a long-term care facility. Beginning with a brief summary of findings from previous research, the article reports on visiting and task performance by families within the long-term care facility. Continuing with descriptions of families' satisfaction with institutional care and their care-related learning needs, the article concludes with recommendations for policy and practice.

Caregivers↗
PubMed2000

Omeprazole, Helicobacter pylori status, and alterations in the intragastric milieu facilitating bacterial N-nitrosation.

BACKGROUND & AIMS: Omeprazole produces greater acid inhibition in Helicobacter pylori-positive than -negative subjects. We investigated whether this is accompanied by more profound changes in the intragastric milieu that facilitates bacterial synthesis of N-nitroso compounds. METHODS: Gastric juice pH; nitrite, ascorbic acid, and total vitamin C concentrations; and colonization by other bacteria were examined before and during omeprazole treatment in subjects with and without H. pylori infection. Studies were performed in the fasting state and after consumption of 2 mmol nitrate (equivalent to a salad meal). RESULTS: Before omeprazole, H. pylori-positive and -negative subjects were similar for all parameters. During omeprazole, H. pylori-positive subjects had a higher intragastric pH (7.8 vs. 3.0; P < 0.00001) and greater colonization with non-H. pylori species (5 x 10(7) vs. 5 x 10(5) CFU/mL; P < 0.05). These bacteria included nitrosating species. During omeprazole treatment, H. pylori-positive subjects had higher intragastric nitrite levels after the nitrate meal (median area under the concentration/time curve, 12,450 vs. 4708 micromol/L. min; P = 0.04). Omeprazole lowered intragastric vitamin C levels in H. pylori-positive but not -negative subjects (1.8 vs. 3.4 microg/mL, respectively; P = 0.02). CONCLUSIONS: In H. pylori-positive subjects, omeprazole produces disturbances in intragastric nitrite, vitamin C, and bacterial colonization that facilitate bacterial N-nitrosation. This may place them at increased risk of mutagenesis and carcinogenesis.

Adult↗
PubMed2000

Teachers' Use of the MABC Checklist to Identify Children with Motor Coordination Difficulties.

Children with motor coordination problems often have difficulty succeeding in the classroom. No previous research could be located in which classroom teachers used screening tools to determine the severity of the children's motor coordination problems or their need for consultation from occupational and physical therapists. The purposes of this study were: 1) to examine the relationship between teachers' scores on the Movement Assessment Battery for Children (MABC) checklist and the physical therapist's scores on the MABC test; and 2) to examine the degree of concordance in decision making by determining if the teachers and physical therapist, using these two measures independently, identified the same children with motor difficulties and those without motor difficulties. Teachers completed the MABC checklist and the physical therapist administered the MABC test to 103 children. The relationship between the teachers' and physical therapist's scores was examined using the Pearson product-moment correlation. Sensitivity and specificity of the checklist were assessed with the MABC test scores as the criterion measure. The correlation between the teachers' scores and the physical therapist's scores was r = 0.51. The sensitivity of the checklist at the 15th percentile cutoff point was 14.3%, and specificity was 97.8%. The sensitivity of the MABC checklist was so low that many children at risk for motor problems based on the MABC test were not identified. Thus, the independent use of this checklist by teachers to identify children with motor coordination problems is not recommended.

Journal Article↗
PubMed1999

Omeprazole and dietary nitrate independently affect levels of vitamin C and nitrite in gastric juice.

BACKGROUND & AIMS: Hypochlorhydria is associated with an increased risk of gastric cancer. We have studied the effect of pharmacologically induced hypochlorhydria on the gastric juice ascorbate/nitrite ratio, which regulates the synthesis of potentially carcinogenic N-nitroso compounds. METHODS: Saliva, gastric juice, and serum from 20 healthy volunteers (9 positive for Helicobacter pylori), with a mean age of 30 years (range, 20-47 years), were analyzed for nitrite, ascorbic acid, and total vitamin C before and for 2 hours after ingestion of 2 mmol [corrected] nitrate (nitrate content of a standard salad meal). This was repeated after 4 weeks of treatment with omeprazole, 40 mg daily. RESULTS: Before omeprazole treatment, the nitrate meal lowered gastric ascorbic acid levels from 3.8 to 0.9 microg/mL (P < 0.05) and increased median salivary nitrite levels from 44 to 262 micromol/L (P < 0.001); gastric nitrite concentration remained undetected in 10 subjects. Omeprazole increased median fasting gastric nitrite levels from 0 to 13 micromol/L (P = 0.001) and decreased fasting gastric ascorbic acid levels from 3.8 to 0.7 microg/mL (P < 0.001). With omeprazole treatment, gastric nitrite levels after the nitrate meal were markedly increased at 154 micromol/L (range, 49-384 micromol/L; P < 0.001). In H. pylori-infected subjects, omeprazole also decreased total vitamin C levels in both gastric juice and serum. CONCLUSIONS: Omeprazole and dietary nitrate independently decrease the ascorbate/nitrite ratio. This may lead to an increased risk of gastric cancer.

Adult↗
PubMed1996

Effects of tiagabine and vigabatrin on GABA uptake into primary cultures of rat cortical astrocytes.

Tiagabine (TGB) and vigabatrin (VGB) are two novel anticonvulsant compounds reported to exert their pharmacological effects via an action on the gamma-aminobutyric acid (GABA) system. We have investigated the effects of acute exposure of these drugs on the uptake of GABA into rat cortical astrocytes in primary culture. Astrocytes were prepared from the cerebral cortices of one day-old rat pups by a mechanical dissociation technique and were assayed for GABA uptake activity after 21 days in culture. Tiagabine (100-300 nM) and VGB (100 microM) reduced GABA uptake when compared to control at four hours post-exposure. GABA uptake was also reduced following eight and 24 hour exposures to 200 nM TGB. A combination of TGB (200 nM) and VGB (100 microM) treatments reduced GABA uptake when compared to both control and VGB treated cultures. These results support the efficacy of TGB as a GABA uptake inhibitor and suggest that VGB may also exert an effect by this mechanism.

Animals↗
PubMed1995

The clinical utility of the Canadian Occupational Performance Measure.

A qualitative research project was undertaken to investigate the clinical utility of the Canadian Occupational Performance Measure (COPM) among therapists from the Regional Municipality of Ottawa-Carleton's Home Care Programme. Nineteen occupational therapists participated in one of four focus groups and in a plenary session to elicit reasons why some therapists used the COPM to assess clients and why others did not. The participants presented a wide range of opinions on the same theme, often from two polarities. The five themes that emerged from the focus groups and which were validated during the plenary session were: Use, environment, administration, outcome and suggested changes. The results demonstrated that COPM utility depended upon the degree to which therapists had incorporated the client-centred approach in their practice, the degree to which management valued and supported the use of the COPM and the degree to which the COPM could be flexible to fit practice context.

Canada↗
PubMed1994

Pilot testing of the Canadian Occupational Performance Measure: clinical and measurement issues.

The Canadian Occupational Performance Measure (COPM) is a measure of a client's self-perception of occupational performance in the areas of self-care, productivity and leisure. The COPM is administered using a semi-structured interview in which the client identifies significant issues in daily activities which are causing difficulty. Extensive pilot testing of the COPM has been completed with 268 clients in communities across Canada and in New Zealand, Greece and Britain. Results indicate the COPM has a median administration time of 30 minutes, is able to identify a wide range of occupational performance issues and appears to be responsive to changes in measurement issues centering around the interview, test construction, scoring, timing of the assessment, respondents, and the assessment process are discussed.

Activities of Daily Living↗
PubMed1993

Double dummy comparison between once and twice daily dosing with modified-release carbamazepine in epileptic patients.

1. Fourteen patients with refractory epilepsy on a twice daily regimen of modified-release carbamazepine (CBZ-MR. Tegretol Retard. Ciba Pharmaceuticals) completed a balanced, double-blind, double dummy, random order, crossover comparison of 8 weeks treatment with once (o.d.) and twice daily (b.d.) dosing. In order to obtain a profile of serum CBZ concentrations over 24 h on once daily dosing, patients were randomised to taking it in the morning (o.d. a.m.) or evening (o.d. p.m.) for 4 weeks. Each treatment was taken with a placebo of the other and total tablet numbers were matched. Blood sampling was undertaken 0, 2, 4, 6, 8, 10, 12 and 24 h after the morning tablets at the end of each 4 week treatment period. 2. Overall, trough serum drug concentrations (Cmin) were lower with once daily dosing (Cmin: b.d. 7.5 mg l-1, o.d. 6.5 mg l-1, P < 0.05, 95% CI of the difference -1.3 to -0.1), but no significant differences were found in average (Cav) or peak (Cmax) concentrations, AUC values or fluctuations in CBZ concentrations. 3. Pharmacokinetic parameters for CBZ 10.11 epoxide, the active metabolite of CBZ did not differ significantly between the dosage schedules. 4. Seizure control was similar during once and twice daily dosing with CBZ-MR (median seizures/month (range): b.d. 1 (0-14.5), o.d. 0.5 (0-11), NS, 95% CI of the difference -1.8 to + 0.25). 5. There were no differences in psychomotor performance between the treatment periods. 6. More patients (n = 11) preferred treatment (P < 0.05) with once daily than twice daily dosing (n = 3) with CBZ-MR. 7. Once daily dosing with CBZ-MR should be possible in the majority of patients receiving the drug as monotherapy.

Adult↗
PubMedDate not supplied

Dose-response relationships with nimodipine against electroshock seizures in mice.

The anticonvulsant effect of the dihydropyridine calcium channel blocker, nimodipine (NMD) was evaluated against electroshock-induced seizures in mice. At 1 h postdosing, NMD elicited a dose-dependent reduction in the occurrence of tonic hindlimb extension (THE) after maximal electroshock (MES). The calculated ED50 for NMD was 87 mg/kg. A single dose of NMD (75 mg/kg) produced a significant (p < 0.05) reduction in occurrence of THE for < or = 12 h postdosing. NMD was detectable for < or = 6 h, and plasma and brain drug concentrations correlated well (r = 0.677, p < 0.01) for that period. At 1 h postdose, a single dose of NMD (75 mg/kg) produced a 40% increase (p < 0.001) in the threshold for tonic seizures as determined by minimal electroshock (Min-ES). NMD is an effective anticonvulsant against experimental seizures induced by electroshock. The pharmacodynamic effect of NMD appears to extend beyond the time anticipated from the pharmacokinetic profile.

Animals↗
PubMedDate not supplied

Continuing education for staff in long-term care facilities: corporate philosophies and approaches.

The purpose of this study was to determine corporate philosophies of continuing education and approaches to meeting the learning needs of staff who strive to provide for the increasingly challenging care requirements of seniors who reside in long-term care facilities. In-depth interviews lasting approximately 1 hour were conducted with key informants at the administrative level from nine long-term care facilities. Content analysis revealed a commitment to continuing education for staff. While recognizing the importance of organizational responsibility for continuing education, administrators placed emphasis on the individual responsibility of staff. Learning needs were identified as affective, managerial, and physical in nature. Challenges to providing continuing education programs were derived from a general lack of fiscal and human resources. A variety of measures was suggested as important to supporting the continuing learning of staff. Implications of this study point to the need for long-term care facilities to incorporate into their strategic plans measures of ensuring continuing education as a basis for the ongoing competence and development of staff. In addition, there is a need for collaboration between long-term care facilities and other institutions of a long-term care, acute care, and educational nature in the development of strategies to operationalize a philosophy of continuing learning as a basis for the provision of optimal care to residents.

Attitude of Health Personnel↗