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Biomedical subjects

G Ross

Publications and source records attributed to G Ross.

333 records · Page 19Linked to original sources
PubMedDate not supplied

Physician profiling decreases inpatient length of stay even with aggressive quality management.

It has been well demonstrated that physician profiling for specific diagnosis-related groups or critical interventions modifies physician behavior. The question this study evaluated was whether the addition of a physician profile that displays average length of stay for all cases admitted to the hospital for the defined period of time modified physician practices in an institution that has well-organized and well-integrated Quality Management, Utilization Review, Discharge Planning, and Social Work Departments. The results of this study demonstrate a positive effect of the physician profile in regard to changes in average length of stay.

Benchmarking↗
PubMedDate not supplied

Interaction of rubber closures with powders for parenteral administration.

The migration of volatile components into the headspace of vials sealed with rubber closures is a potential source of haze formation in solutions of reconstituted powders for parenteral administration. Different types of vial closures were examined to determine their propensity to release volatile compounds. It was possible to accumulate the volatiles in a cold trap by means of thermal desorption and dynamic headspace. Gas chromatography coupled with mass spectrometry was then used to characterize the volatiles isolated. Components found in the headspace of butyl and halogenated butyl rubber closures included saturated hydrocarbons, unchlorinated or chlorinated olefins, alkylbenzenes, and low molecular weight polydimethylsiloxanes.

Drug Contamination↗
PubMedDate not supplied

Aqueductal obstruction in sarcoidosis.

A 50-year-old woman presented with a severe obstructive hydrocephalus, only temporarily relieved by shunts. The diagnosis of sarcoidosis was suspected but never proven. Autopsy revealed multisystem sarcoidosis as well as widespread involvement of the CNS. The cause of hydrocephalus was established as occlusion of the aqueduct by subependymal granulomas and massive gliosis obliterating the lumen.

Cerebral Aqueduct↗
PubMedDate not supplied

Usefulness of magnetic resonance imaging for the diagnosis of acute musculoskeletal infections in children.

A 30-month prospective study was conducted on 43 children who presented with clinical findings suggestive of acute hematogenous musculoskeletal infection. Magnetic resonance imaging (MRI) was found to be extremely sensitive (0.97) and specific (0.92) in helping to diagnose these infections, with only one false positive and one false negative study. Bone scans are more likely to yield false positive and negative examinations. MRI is particularly useful in difficult cases in which there are conflicting clinical data or infection involving the spine or pelvis. After MRI demonstrates the location of the disease process, histologic and/or bacteriologic confirmation of the etiology is still mandatory.

Acute Disease↗
PubMedDate not supplied

Muscle testing response to provocative vertebral challenge and spinal manipulation: a randomized controlled trial of construct validity.

OBJECTIVE: To evaluate the relationship of muscle strength response to a provocative vertebral challenge and to spinal manipulation. DESIGN: Prospective double-blind randomized controlled trial: crossover and between subjects designs. SETTING: Laboratory: Center for Technique Research. PARTICIPANTS: Sixty-eight naive volunteers from the student body, staff and faculty of the college. INTERVENTIONS: Provocative vertebral challenge: standardized 4-5 kg force applied with a pressure algometer to the lateral aspects of the T3-12 spinous processes. INTERVENTION: manual high velocity low amplitude adjustment or switched-off activator sham. MAIN OUTCOME MEASURES: Piriformis muscle response was defined in two ways: reactivity (a decrease in muscle resistance, yes or nor, following a vertebral challenge); responsiveness (the cessation of reactivity following spinal manipulation). Relative response attributable to the maneuver (RRAM): the percent of an outcome attributable to the challenge or adjustment itself. RESULTS: Average RRAM = 16% reactivity to vertebral challenge; average RRAM = 0% responsiveness to spinal manipulation. Six to 10% of muscle tests were positive regardless of examiner, previous finding or intervention. CONCLUSIONS: For the population under investigation, muscle response appeared to be a random phenomenon unrelated to manipulable subluxation. In and of itself, muscle testing appears to be of questionable use for spinal screening and post-adjustive evaluation. Further research is indicated in more symptomatic populations, different regions of the spine, and using different indicator muscles.

Adult↗
PubMedDate not supplied

Effect of collagen microparticles on the stability of retinol and its absorption into hairless mouse skin in vitro.

Collagen microparticles (CMPs) were manufactured with the objective to enhance the dermal delivery of all-trans retinol. The influence of CMPs on the stability of retinol was investigated after a long-term storage of two hydrogel preparations (hydroxyethylcellulose). The retinol in the first preparation was adsorbed onto the surface of CMPs, whereas the retinol in the second preparation was freshly precipitated. Retinol was not protected from oxidization by adsorption to CMPs. However, the sorption on the surface of CMPs prevented the retinol from crystallization. On the other hand, significant crystallization occurred with the freshly precipitated retinol. For the study of the in vitro penetration of retinol into hairless mouse skin three preparations for topical application were used. Beside the two hydrogel preparations mentioned above, an O/W-creme was tested. The study of the in vitro penetration was performed by using Franz diffusion cells and tritium labelled retinol. Both hydrogel preparations yielded significantly higher quantities of penetrated retinol than the O/W-creme. The amounts of radioactive retinol in the stratum corneum and in the epidermis and dermis were in all cases more than ten times higher for the hydrogel preparations. The other remarkable result was that the presence of CMPs led to a faster and higher transport of retinol into the skin than the freshly precipitated drug. With the CMP preparation a statistically significant increase of penetrated retinol was found during the first 4 h after application in the stratum corneum. In the residual epidermis and dermis a clear tendency towards enhanced quantities of penetrated retinol also were observed with the CMPs compared to the freshly precipitated drug in the hydrogel.

Animals↗
PubMedDate not supplied

Does cholestyramine interfere with cyclosporine absorption? A prospective study in renal transplant patients.

Increased cardiovascular deaths have been reported in long-term survivors after renal transplantation. In the primary and secondary coronary prevention trials, reduction of elevated cholesterol has been demonstrated to decrease the incidence of cardiovascular events. The authors previously reported that only 33% of renal transplant patients achieved the National Cholesterol Education Program Expert Panel target values of total and low density lipoprotein cholesterol with niacin > or = 2 g/day or lovastatin 40 mg/day. Indeed, combination therapy with the bile acid sequestrant, cholestyramine appears to be a logical choice. Hence, the pharmacokinetics of cyclosporine were studies before (baseline, on day 1) and after starting cholestyramine 4 g/day, given as a single dose at noon (study repeated on day 4) in six nondiabetic renal transplant patients. Included were 1 woman and 5 men; their mean age (+/- SEM) was 45 +/- 6 years, and they were all > 1 year post transplantation. These patients were receiving cyclosporine, azathioprine, and prednisone based maintenance immunosuppression. Compared to day 1 (baseline period), the peak (644 +/- 142 ng/ml versus 625 +/- 168 ng/ml; ns) and trough (196 +/- 17 ng/ml versus 214 +/- 32 ng/ml; ns) cyclosporine levels and the time to peak (2 hr versus 2 hr) were not significantly different on day 4 (post cholestyramine period) of the study. Furthermore, the area under the curve (3721 +/- 586 ng/hour/ml versus 4143 +/- 778 ng/hour/ml; ns) was not significantly different. Our data suggest that cholestyramine 4 g, given once a day at noon, did not interfere with the absorption of oral cyclosporine. Hence, combination therapy with cholestyramine appears to be a reasonable choice in renal transplant patients with resistant hypercholesterolemia.

Adult↗
PubMedDate not supplied

Advances in capillary electrochromatography.

This paper presents practical aspects of capillary electrochromatography (CEC). Preparation of capillary columns, including terminating frits and immobilization of the packed bed, is described in detail. Longevity and reproducibility of CEC columns is demonstrated. Instrumental aspects, sample introduction, sensitivity of detection, and gradient elution are discussed in detail. A number of examples that illustrate the versatility of CEC, in particular, for providing an isocratic separation alternative to conventional gradient separation in HPLC, are given.

Chromatography↗