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Biomedical subjects

K O'Brien

Publications and source records attributed to K O'Brien.

At least 73 records · Page 4Linked to original sources
PubMed1991

Mineral homeostasis in obesity: effects of euglycemic hyperinsulinemia.

We explored the effects of insulin on mineral homeostasis in five lean and six moderately obese nondiabetic premenopausal women. Serum and urine minerals were measured before and during the steady-state phase of a euglycemic insulin clamp. Each subject participated in two insulin clamp studies on separate days at insulin infusion rates of 10 and 40 mU/m2/min. Euglycemic hyperinsulinemia was associated with (1) a significant increase in urinary calcium excretion when expressed per minute with no change in total serum calcium; (2) a decrease in urine and serum phosphate; (3) a decrease in serum potassium with no change in urine potassium; and (4) no measurable effects on urine or serum sodium. At any given insulin level, the obese individuals excreted significantly more calcium, phosphate, and potassium per minute than lean controls. While insulin administration had no effect on serum parathyroid hormone (PTH) or vitamin D levels, baseline serum 1,25(OH)2D concentration was significantly higher and serum ultrafilterable calcium was significantly lower in obese subjects than in lean controls.

Adult↗
PubMed1991

Lipogenic potential of liver from morbidly obese patients with and without non-insulin-dependent diabetes.

Intra-abdominal liver biopsies were obtained during surgery from fasted obese patients with non-insulin-dependent diabetes mellitus (NIDDM), obese normoglycemic controls, and lean controls. Lipid synthesis was studied in freshly isolated hepatocytes and liver homogenates from the three groups of subjects. Incorporation of 3H2O into the lipids of hepatocytes was determined in the absence and presence of insulin (0.1 mumol/L). The activities of five enzymes involved in fatty acid synthesis, and the incorporation of 14C-glycerol-3-phosphate into lipids were determined in liver homogenates. Basal lipid synthesis by hepatocytes was not different in the three groups of patients. Insulin stimulated lipogenesis by 8% +/- 30% in the lean controls, 33% +/- 8% in the obese controls and 17% +/- 6% in the NIDDM patients. No significant differences in the activities of the five enzymes that are involved in de novo fatty acid synthesis among the three groups of patients were observed. Similarly, incorporation of 14C-glycerol-3-phosphate by liver homogenates, in the presence of saturating or submaximal concentrations of fatty acids, did not differ among the three groups. These results show that under the experimental conditions of this study, including the fasted state of the patients, the basal capacity of liver of NIDDM patients to synthesize fatty acids or glycerides is the same as that of liver from obese and lean controls. Thus, it is likely that an increase in fatty acid flux into a liver with normal lipogenic potential may contribute to the increased synthesis of triglycerides by the liver of these patients in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Regulation of proline utilization in Salmonella typhimurium: a membrane-associated dehydrogenase binds DNA in vitro.

The PutA protein is a membrane-associated enzyme that catalyzes the degradation of proline to glutamate. Genetic evidence suggests that in the absence of proline, the PutA protein also represses transcription of the putA and putP genes. To directly determine whether PutA protein binds to the put control region, we analyzed gel retardation of put control region DNA by purified PutA protein in vitro. The put control region is 420 bp. Purified PutA protein bound specifically to several nonoverlapping fragments of control region DNA, indicating the presence of multiple binding sites in the control region. Electrophoretic abnormalities and behavior of circularly permuted fragments of control region DNA indicate that it contains a region of intrinsically curved DNA. To determine whether the multiple binding sites or the DNA curvature are important in vivo, two types of deletions were constructed: (i) deletions that removed sequences predicted to contribute to DNA curvature as well as potential operator sites and (ii) deletions that removed only potential operator sites. Both types of deletions increased expression of the put genes but were still induced by proline, indicating that multiple cis elements are involved in repression. These data suggest a model for put repression that invokes the formation of a complex between PutA protein molecules bound at different sites in the control region, brought into proximity by a loop of curved DNA.

1-Pyrroline-5-Carboxylate Dehydrogenase↗
PubMed1991

Orthodontic interactions: the relationships between the orthodontic services in England and Wales.

The manpower distribution and the amount of treatment undertaken by the three orthodontic treatment providing groups was calculated on a national and regional basis. There was marked regional variation in the distribution of orthodontic manpower. It was found that the total orthodontic treatment rate correlated with the distributions of specialist practitioners and general dental practitioners, but not with that of the salaried services. The manpower distribution of specialist practitioners and Community Orthodontists was also related. These results are discussed in terms of the effect of manpower distribution upon demand for treatment and the amount of treatment provided by the orthodontic services.

Adolescent↗
PubMed1991

Interleukin-2 and high-dose cisplatin in patients with metastatic melanoma: a pilot study.

In this pilot study of metastatic melanoma, interleukin-2 (IL-2) and cisplatin (CDDP) chemotherapy were combined using an alternating schedule designed to explore potential synergism between these modalities. Bolus IL-2 was given at a dose of 600,000 IU/kg intravenously (IV) every 8 hours, days 1 to 5 and 15 to 19, followed by high-dose CDDP administered by two different regimens: (A) 135 to 150 mg/m2 IV bolus over 30 minutes with the chemoprotectant WR-2721 910 mg/m2 or (B) 50 mg/m2 IV over 2 hours every day for 3 days. The trial design allowed an assessment of response to each phase of therapy. Among 27 assessable patients, there were 10 (37%) overall responses, including three (11%) complete responses (CRs) with durations of 9, 16, and 30+ months. Tumor regression was noted in seven patients (partial response [PR], four; minor response [MR], three; response rate [RR], four of 27 [15%]) after IL-2 administration and in 14 patients (PR, 12; MR, two; RR, 12 of 27 [44%]) after CDDP treatment, demonstrating noncrossresistance between the components of the regimen. Major PRs (greater than 90% reduction of tumor burden) or CRs were only seen in patients responding to IL-2. Toxicity during IL-2 therapy was typical for high-dose IL-2 protocols and was reversible. Among the first 20 patients treated with CDDP regimen A, there were eight episodes of grade IV nephrotoxicity (creatinine level greater than 5.0 mg/dL), including three of six patients treated with an initial CDDP dose of 135 mg/m2. This side effect was more frequent among patients with liver metastasis (P less than .05, Fisher's exact test). No significant nephrotoxicity was noted in seven patients treated on regimen B. Although ototoxicity was frequent, minimal bone marrow and neurologic toxicity was noted. There were no treatment-related deaths. This combination showed at least additive activity against melanoma, and the more protracted CDDP schedule was well tolerated. This regimen may serve as a model for future combined immunotherapy and chemotherapy trials in metastatic melanoma.

Adult↗
PubMed1991

Gallium-SPECT in the detection of prosthetic valve endocarditis and aortic ring abscess.

A 52-yr-old man who had a bioprosthetic aortic valve developed Staphylococcus aureus bacteremia. Despite antibiotic therapy he had persistent pyrexia and developed new conduction system disturbances. Echocardiography did not demonstrate vegetations on the valve or an abscess, but gallium scintigraphy using SPECT clearly identified a focus of intense activity in the region of the aortic valve. The presence of valvular vegetations and a septal abscess was confirmed at autopsy. Gallium scintigraphy, using SPECT, provided a useful noninvasive method for the demonstration of endocarditis and the associated valve ring abscess.

Abscess↗
PubMed1991

Patient care plans for intershift report.

Inconsistent communication during intershift report had resulted in loss of vital information. This project was developed to implement the use of nursing care plans for intershift report on a 25-bed school-age unit. A review of literature showed an absence of any systematic method for intershift report. Classes that included a 20-minute video, written guidelines, and discussion were used to promote the use of nursing care plans for intershift report. A questionnaire was administered to the nursing staff 3 weeks after class to evaluate the project. The evaluation of use of the care plans indicated: (a) a more focused intershift report; (b) an improved structure for report, including important information about the child and family; (c) increased communication; (d) more practical up-to-date care plans; and (e) increased professionalism and collaboration.

Child↗
PubMed1990

Regional distribution of cholecystokinin messenger RNA in rat brain during development: quantitation and correlation with cholecystokinin immunoreactivity.

The regional distribution of CCK-octapeptide (CCK) and CCKmRNA were studied in parallel in rat brain during development in order to characterize changes in gene expression in different structures at different periods of development and to determine whether differential regulation of translation and peptide turnover occurs, by correlating peptide and mRNA levels. CCK was characterized by Northern blot analysis. Methods were developed for quantitation of CCKmRNA by in situ hybridization (ISH) and compared with results obtained by slot blot analysis. Analysis of CCKmRNA by ISH showed that CCKmRNA was abundant in cerebral cortex, hippocampus, dentate gyrus, thalamus, inferior colliculus and periaqueductal grey in keeping with the high concentrations of CCK-like immunoreactivity in cell bodies located in these regions. Quantitation of CCKmRNA by computerized densitometric image analysis by reference to [35S]brain paste standards gave a similar pattern to that obtained by slot blot analysis of regional RNA extracts. Distinctive patterns of CCK development were seen. In cerebral cortex and hippocampus, a marked increase in peptide and mRNA levels was found from day 1 which showed a steady increase up to adult levels. However, in the thalamus, the highest levels of mRNA and peptide were reached at a much earlier stage, generally by 14d. In contrast, inferior and superior colliculus showed a delayed onset of peptide expression.

Animals↗
PubMed1990

A clinical trial of aligning archwires.

The physical properties of a super-elastic archwire alloy (Titanol) and Nitinol were investigated by the means of a bending test. It was found that the alloy possessed super-elastic properties. A clinical trial was then carried out to compare the properties of two types of aligning archwire. Two groups of 20 patients with crowded dentitions were randomly allocated either Titanol or Nitinol, a conventional nickel-titanium alloy aligning archwire. High quality alginate impressions were taken after archwire placement in Edgewise fixed appliances and were repeated after a mean period of 35 days. The impressions were cast in dental stone and digitized using the Reflex Metrograph. The contact points of the teeth of the labial segments, together with four stable points in the rugae were recorded. This enabled the co-ordinates for the sequential study models to be superimposed upon one another, allowing tooth movement in three dimensions to be calculated. The measurement error expressed as error variance was 0.028 mm. The coefficient of reliability was 97 per cent. When tooth movement was analysed the mean movement per contact point for Titanol was 1.7 mm and for Nitinol 1.42 mm. This difference was not statistically significant (P less than 0.05, t-test). However, a clinical impression was that the super-elastic archwire proved superior to the Nitinol, because it was more readily engaged into grossly displaced teeth.

Adolescent↗
PubMed1990

An analysis of retrospective data concerning the provision of orthodontic treatment by the community dental services.

The distribution of both community orthodontic and dental officer manpower has been reviewed, and both exhibit an unequal regional variation. The amount of orthodontic treatment provided was calculated, and expressed as a treatment rate and percentage of fixed: removable appliances fitted. There was a marked regional variation in the form of appliance utilized, and there was a significant relationship between community orthodontic manpower and the relative use of fixed appliances. However, the treatment rate was not related to the manpower distribution. The data collected, by the Department of Health, on the provision of orthodontic treatment was found to have some limitations in its usefulness for epidemiological purposes.

Adolescent↗
PubMed1990

Regional variation in the provision of orthodontic treatment by the hospital services in England and Wales.

The regional variation in hospital orthodontic manpower, referral rate, and hospital treatment rate for the 5-15-year-old population was calculated, a marked regional variation was evident. In addition, relevant data from the Consultant Orthodontist Survey of 1985 was also analysed on a regional basis, in order to evaluate any interactions between the above variables and the type of treatment provided, the proportion of referred patients accepted, and treatment priority of patients referred. It was found that the hospital treatment rate was related to the referral rate, no other relevant significant correlations between the variables were detected. Possible explanations are discussed.

Adolescent↗
PubMed1990

Salt taste preferences and perceptions of elderly and young adults.

Current research has yielded both support and refutation for the theory that elderly adults have lower taste acuity. The present study compared the perception of and preference for salt in persons 65 years and over and in persons aged 20 to 35 years. The subjects were free-living, had not been hospitalized in the past 12 months, and had never been on a sodium-restricted diet. Salt was introduced in suprathreshold concentrations of 0.3%, 0.5%, 0.7%, and 0.9% in mashed potatoes and chicken broth. The 48 older adults in our study demonstrated higher preferences for the four salt concentrations in the potatoes (p = .0001) and the broth (p = .0004) than did the 53 younger adults. There were no significant differences in the two age groups' abilities to perceive the saltiness of the four concentrations. There were also no significant differences in salt perception among subgroups identified for age, gender, smoking behavior, and denture use. Both groups correctly ranked the concentrations in ascending order. Our study found that taste acuity for salt in older subjects was not different from that of younger adults when suprathreshold concentrations of salt in mashed potatoes and chicken broth were used as stimuli.

Adult↗
PubMed1990

Comparison of perceived needs of family members between registered nurses and family members of critically ill patients in intensive care and neonatal intensive care units.

Using the Norris and Grove (1986) questionnaire of perceived needs of families of critically ill patients, 11 registered nurses working in the neonatal intensive care unit and 19 registered nurses working in the intensive care unit of two mid-northern community hospitals provided their perceptions of family needs. Their responses were compared with responses of family members of patients in the intensive care unit (n = 25) and the (n = 24). Results suggest that regardless of unit, registered nurses' perceptions of family needs are congruent. Family members collectively and by unit ranked their needs consistently higher and in some areas differently than did the registered nurses.

Adult↗
PubMed1990

The effect of patient-carried reminder cards on the performance of health maintenance measures.

We designed a card that patients carried and showed to their physicians at scheduled appointments to remind them to perform six health maintenance procedures: influenza vaccination, pneumococcal vaccination, rectal examination and hemoccult test, Papanicolaou's smear, physician breast examination, and mammography. Prompt sheets were also attached to all charts to remind physicians to perform these same procedures. One hundred seventy-five patients received the card and the physician prompt sheets on their charts. Two hundred forty-eight patients received only physician's prompt sheet. The card group had significant increases in the performance of influenza vaccinations (47% vs 29%), rectal examination and hemoccult tests (59% vs 46%), Papanicolaou's smears, (30% vs 20%), and physician breast examinations (52% vs 29%). There was not a significant increase in the performance of pneumococcal vaccines (22% vs 24%) or mammography (18% vs 19%). We conclude that patient-carried health maintenance reminder cards are useful in increasing the physician performance of influenza vaccinations, rectal examinations and hemoccult tests, Papanicolaou's smears, and breast examinations.

Adult↗