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Biomedical subjects

R W Thomas

Publications and source records attributed to R W Thomas.

At least 19 recordsLinked to original sources
PubMed2001

Magnetic resonance: magic angle imaging of the Achilles tendon.

Tendons do not normally produce detectable signals with conventional magnetic-resonance techniques and are recognised as dark signal voids. However, if tendons are examined at 55 degrees to the static magnetic field (the "magic angle"), signals become detectable and the tendons can become the brightest structure on the image. We have used this approach to establish tendon relaxation times and magnetisation transfer ratios and to show contrast enhancement. We have also shown more detail of acute and chronic tendon rupture by this method compared with images made with the tendon parallel to the static magnetic field.

Achilles Tendon↗
PubMed2000

Levels of personal agency among academic majors.

Action identification theory presented by Vallacher and Wegner characterizes individual differences in identification level in terms of a personality dimension known as "level of personal agency." Levels of personal agency, as measured by the Behavior Identification Form, were examined in a sample of 237 college "seniors" representing eight academic majors. The mean levels of personal agency among individuals in several of these majors were significantly different.

Adult↗
PubMed1999

Effect of the Palmaz balloon-expandable metallic stent in the trachea of pigs.

Endoscopically placed airway stents offer a viable option in primary or adjunctive treatment of severe pediatric tracheobronchial stenoses. Optimistic clinical reports substantiate the need for experimental studies to more effectively evaluate their clinical role. Development of an animal model comparable with the pediatric airway, amenable to endoscopic instrumentation, and capable of assessing effect on growth was the purpose of this pilot project. Nine 4-week-old piglets underwent endoscopic midtracheal placement of the balloon-expandable Palmaz metallic stent. Initial expansion and stent position were verified fluoroscopically and by direct videobronchoscopy. Serial endoscopic examination and stent reexpansion were performed 2 and 4 weeks after stent insertion. Animal weight, clinical tolerance, tracheal growth, and stent integrity were observed. Tracheal inflammation was evaluated grossly and by objective histopathologic criteria. Successful endotracheal stent placement and expansion were accomplished in all piglets. One pig died of anesthesia complications less than 24 hours after stent insertion. The remaining pigs exhibited excellent clinical tolerance through experiment completion. No detrimental effect on growth was noted, and effective dilatation of the stented tracheal region was observed. Stent incorporation was evident with significant mucosal ingrowth. Inflammation in the form of nonobstructing granulation tissue was present, and no evidence of necrosis or cartilage invasion was evident. The piglet trachea appears to be an excellent model for evaluation of expandable metallic airway stents in management of congenital and acquired tracheobronchial stenoses.

Animals↗
PubMed1999

Cranial polyneuropathies in multiple sclerosis: case report and literature review.

Although cranial neuropathies are common disorders in multiple sclerosis patients, multiple cranial nerve involvement is an unusual occurrence. Correlation of clinical symptoms with magnetic resonance imaging evidence of demyelinating central nervous system lesions can confirm the diagnosis. The authors report on the case of a 43-year-old woman who initially was thought to have suffered a brainstem infarct but, in fact, had developed multiple cranial nerve functional deficits. Treatment of multiple sclerosis remains primarily supportive in nature, with corticosteroids used for acute exacerbations and chronic progression.

Adult↗
PubMed1999

Surgical excision of pilomatrixoma of the head and neck: a retrospective review of 26 cases.

The objective of this article is to describe our experiences in treating patients for head and neck pilomatrixoma at our institution during a 5-year period and to compare our findings with previously published results. To that end, we conducted a 5-year retrospective chart review to identify those patients who had a confirmed histopathologic diagnosis of pilomatrixoma involving the head and neck area. We reviewed medical records for presenting signs and symptoms, lesion characteristics, treatment rendered, and outcomes. We identified 26 patients, aged 6 to 77 (mean: 33), who met the criteria for inclusion in our study. All had been treated for solitary tumors with simple surgical excision and closure. We found no reported adverse outcomes and no tumor recurrences at the surgical sites. These findings support the use of simple surgical excision as the treatment of choice for these tumors.

Adolescent↗
PubMed1995

College students' decisions to intervene in alcohol-related situations.

OBJECTIVE: In reviewing research on college students' intervention practices in alcohol-related situations, Seibold and Thomas recently advanced a transactional influence reconceptualization of intervention episodes. This study sought to explicate the factors contributing to college students' decision to intervene or not to intervene in alcohol-related situations. METHOD: In order to empirically explore this area, 489 students from three U.S. universities were surveyed about factors affecting their decisions to intervene or not in two types of alcohol-related situations: a drunk-driving situation and an alcohol abuse situation. RESULTS: Students' intervention decisions were motivated primarily by concerns for the target and for potential consequences if they did not intervene. In contrast, decisions not to intervene were motivated primarily by an absence of a strong relationship with the target, their own condition at the time, and the potential impact of the intervention attempt on their image. Gender differences moderated many of these findings, however. CONCLUSIONS: Results are discussed in terms of approaching the study of alcohol interventions from a transactional influence perspective.

Adolescent↗
PubMed1994

An evaluation of the role of the ED in the management of migraine headaches.

The objective of this study was to describe the characteristics and clinical course of patients who receive emergency department (ED) migraine treatment and their association with frequent ED visits. All migraine patient records during a 42-month period were reviewed retrospectively at an urban teaching hospital ED. One hundred eighty-five migraine patients had 339 total visits; 133 had a single visit; 31 had two visits; and 21 patients had three or more ED visits (range, 3 to 26 visits). Patients with three or more visits accounted for 42.5% of all ED migraine visits. Drugs were administered in 82.3%, and efficacy was documented in 49% of ED visits. Complete or considerable relief was noted in 64.5% of visits. Drug abuse was infrequently identified in migraine patients. Most migraine patients seem to use the ED appropriately. A small group (11.4%) of patients accounted for 42.5% of all ED visits. Given the nature of severe, frequent migraines and the current lack of consistently effective therapy, this may be a common ED phenomenon. More effective management strategies and therapy that will enable patients to reduce their dependence on the ED for treatment would be useful for patients with multiple ED visits.

Adult↗
PubMed1990

An analysis of psychiatric patient attributes in Salford using categorical data models.

Much geographical work about mental illness has been aggregative in nature and, consequently, has ignored variation that might be attributed to individuals. The research reported here is intended to reverse this trend by applying the methods of categorical data analysis to the detailed patient histories contained in the Salford Psychiatric Case Register. The paper begins by reviewing the changing prevalence rates for various diagnoses and types of care in Salford between 1968 and 1986. In the light of this background log-linear data models are fitted to evaluate relationships between service usage and patient age, diagnosis and marital status and residential location at two survey points within the study period. Significant relationships are examined in terms of their temporal stability (such as the diagnosis of schizophrenia and a marital status of single) and instability (the changing role of the community psychiatric nurse) to isolate the main combinations of categories to influence the uptake of psychiatric services.

Adolescent↗
PubMed1988

Multiple-dose cimetidine administration does not influence the single-dose pharmacokinetics of quinapril and its active metabolite (CI-928).

The potential effect of cimetidine on the pharmacokinetic profiles of quinapril and its active metabolite CI-928 was evaluated in eight healthy volunteers. Each subject received a single 40-mg quinapril dose on days 1 and 12 and cimetidine 300 mg four times daily on days 8 through 13. Serial blood and urine samples were collected for assay of quinapril and CI-928 concentrations. No statistically significant differences were observed in quinapril or CI-928 Cmax, tmax, AUC(0-infinity), beta, or percent of dose excreted in urine values for quinapril administered alone and in combination with cimetidine. Therefore, multiple-dose cimetidine administration does not influence the single-dose pharmacokinetics of quinapril and its active metabolite, CI-928, in healthy volunteers.

Adult↗
PubMed1988

Carrier models for the simulation of Hodgkin's disease: a review with some extensions.

Epidemiologists have unearthed a good deal of both anecdotal and statistical evidence to suggest that Hodgkin's disease might be a transmissible entity. This paper critically reviews those findings which have led to the building of a single-region carrier model capable of making deterministic simulations for the temporal incidence of Hodgkin's disease. The results of fitting this model to the monthly incidence of the disease in Greater Manchester between 1962 and 1976 are discussed in relation to the plausibility of the equilibria associated with the more realistic solutions. In the light of this evaluation, the specification of the model is extended to include multi-region settings with more complex infective mechanisms. Finally, the improvements that accrue from adopting a stochastic modelling style are outlined.

Carrier State↗
PubMed1986

Gentamicin dosage recommendations for neonates based on half-life predictions from birthweight.

The appropriate dosing of gentamicin in the newborn was evaluated. Gentamicin was administered intramuscularly to 151 neonates ranging in birthweight from 0.66 to 4.7 kg (gestational age, 26-42 weeks) during a 7-month period. A dosage of 2.5 mg/kg of birthweight every 12 hours was initiated at birth until gentamicin serum levels could be determined. These infants were divided into three groups based on birthweight: 1) less than or equal to 1000 gm; 2) 1001-2000 gm; 3) greater than 2000 gm. From gentamicin serum level data, these three groups had significantly different (P less than 0.05) gentamicin half-lives. Based on the desirability of maintaining a trough gentamicin serum level less than 2, 100, 95.5, and 39% of infants in groups 1, 2, and 3, respectively, required initial dosing interval adjustments. A second group of 74 infants whose birthweight ranged from 0.82 to 3.9 kg (gestational age, 26-42 weeks) required aminoglycoside therapy and were prospectively placed on gentamicin 2.5 mg/kg of birthweight on the following schedule: 1) less than or equal to 1000 gm every 24 hours; 2) 1001-2000 gm every 18 hours; 3) greater than 2000 gm every 12 hours. Using this method, only 15, 58, and 33% of infants in groups 1, 2, and 3, respectively, required dosing interval changes. We conclude that a marked reduction in undesirably high trough gentamicin serum levels can be affected by a simple change in dosing interval based on birthweight, although gentamicin serum levels are still required due to a significant number of infants with high trough levels.

Bacterial Infections↗
PubMed1985

Effect of acute alcohol consumption on lithium kinetics.

Lithium carbonate is used in several psychiatric disorders in the context of alcohol abuse. In a randomized, double-blind, crossover study the single-dose kinetics of lithium were followed after alcohol or placebo. Lithium carbonate capsules were taken by mouth by 10 healthy young men with alcohol on one occasion and with placebo on a separate occasion (at least 7 days apart). Lithium concentrations were determined in serum and urine samples for 24 hours after dosing and served as the basis for kinetic analysis. Acute alcohol had no effect on lithium absorption, elimination, distribution, or clearance. Alcohol did, however, increase the peak serum lithium level in nine of 10 subjects, from a mean of 0.62 mEq/L in the placebo condition to 0.70 mEq/L in the alcohol condition. Our data suggest that alcohol has limited effects on lithium carbonate kinetics. The possibility of elevated serum lithium concentrations when lithium is taken with alcohol is suggested.

Absorption↗
PubMed1985

Space-time interaction in Hodgkin's disease in Greater Manchester.

Knox's test for space-time interaction was applied to 922 cases of Hodgkin's disease which, according to the North Western Regional Cancer Registry, had presented in 1962-76 among the population of the region known before 1974 as the South East Lancashire Conurbation. In the series as a whole, there were statistically significant excesses of pairs of patients separated by time intervals of less than a year and distances of less than 1 km. Analysis by age and sex indicated that this clustering involved (a) a trio of young females and (b) pairs involving adults over 45 years old. No evidence was detected of any clustering by histological subtype or of any tendency for cases close in space to be separated by long time intervals of specific duration. These findings lend support to the idea that at least some cases of Hodgkin's disease may be induced by an infection or other environmental influence, but they do not suggest that such an infection has a long and specific incubation period.

Adolescent↗