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Biomedical subjects

R Thomas

Publications and source records attributed to R Thomas.

At least 397 records · Page 22Linked to original sources
PubMed1994

Rheumatoid synovium is enriched in mature antigen-presenting dendritic cells.

Monocytes and dendritic cells (DC) can be purified from fresh peripheral blood (PB) based on their expression of CD33, CD13, and CD14. Whereas DC can be identified as CD33+ CD14dim or CD13+CD14dim cells, monocytes can be identified as CD33+CD14bright or CD13+CD14bright cells. Rheumatoid synovial fluid (SF) and synovial tissue (ST) non-T cells were found to be enriched in CD33+CD14dim cells compared with PB. Whereas 4 to 14% of normal or rheumatoid PB non-T cells were CD33+ and CD14dim, in rheumatoid SF or ST these cells comprised 20 to 45% of non-T mononuclear cells. Synovial CD33+CD14dim cells assumed a typical dendritic morphology on in vitro culture. Freshly isolated CD33+CD14dim PB DC precursors express low levels of HLA-DQ, CD40, and B7, which increase after in vitro incubation. In contrast, freshly isolated SF DC constitutively expressed these markers, and increased densities of HLA-DR and MHC class I molecules. Rheumatoid SF DC showed a specifically enhanced ability to stimulate autologous PB T cells compared with PB DC, or PB or SF monocytes. PB DC or monocytes preincubated in granulocyte-macrophage-CSF, TNF-alpha, or both cytokines exhibited enhanced expression of HLA-DR. Furthermore, DC preincubated in both granulocyte-macrophage-CSF and TNF-alpha were better stimulators of the autologous MLR than DC preincubated in medium, or in either cytokine alone. The data indicate that DC are enriched in rheumatoid SF and ST, and display a more differentiated phenotype than PB DC. These results suggest that PB DC accumulate in the synovium where they undergo phenotypic and functional differentiation in situ, which may be mediated by local cytokines. DC may play an important role in the ongoing presentation of antigen to autoreactive T cells in RA synovium.

Adult↗
PubMed1994

Space exploration and toxicology: a new frontier.

Results of the microbial and immunological studies discussed above clearly illustrate an in-flight or post-flight blunting of the cellular immune mechanism in humans and test animals, coincident with a relative increase in pathogenic microorganisms. This situation predicts an increased incidence of in-flight infectious disease events. To prevent this from occurring, most observers agree that a robust program of preflight and in-flight immunological and microbiological monitoring, combined with an effective countermeasures program, are required for optimally successful long-duration spaceflight.

Animals↗
PubMed1994

Tulane experience with management of urinary incontinence after placement of an artificial urinary sphincter.

Persistent urinary incontinence following placement of an artificial urinary sphincter (AUS) presents a challenging diagnostic problem. This report reviews 30 cases (27 males and 3 females) involving urinary incontinence following AUS placement. The mean age of the patients was 64.4 years (range, 10-79 years). Physical examination demonstrated evidence or suspicion of infection or erosion in 7 patients, and subsequent cystoscopic examination revealed erosion caused by the cuff in 6 of these 7 cases. The remaining 23 patients were evaluated by videofluorourodynamics (VFUD) to ascertain the cause of incontinence. VFUD demonstrated detrusor instability in 9 patients (39%), low detrusor compliance in 3 patients (13%), and poor detrusor contractility in 1 patient (4.4%). Bladder-outlet obstruction was diagnosed in 2 patients (8.8%)-1 with bladder-neck contracture and 1 with ureteral stricture. Altogether, 2 (8.8%) cases of tissue atrophy were diagnosed with low urethral closing pressure at the cuff. In all, 1 patient (4.4%) was diagnosed as having a vesicovaginal fistula, 1 (4.4%) had a tubing kink, and 4 (17%) had leaking devices diagnosed during VFUD by cycling of the device. Of the 23 patients, 21 (91%) demonstrably improve or became fully continent after appropriate treatment had been initiated. A review of this study suggests that the majority of incontinent patients after AUS implantation can be managed successfully, provided that a systematic diagnostic approach is followed and appropriate treatment is initiated.

Algorithms↗
PubMed1994

Pediatric urolithiasis: review of research and current management.

The treatment of urolithiasis in children has changed dramatically in recent years. With the proven safety and efficacy of extracorporeal shock wave lithotripsy (ESWL), percutaneous lithotripsy and ureteroscopy in adults, these modalities are now in the forefront of the treatment of pediatric urinary stones. Our research in the juvenile non-human primate with ESWL indicates that renal damage in most cases is neither significant or persistent. In addition, technological advances in instrumentation have cleared the way for the use of percutaneous lithotripsy and ureteroscopy in most pediatric patients. Today, open surgical procedures for stone disease in children should be a last resort.

Child, Preschool↗
PubMed1994

Hypofractionated radiotherapy as palliative treatment in poor prognosis patients with high grade glioma.

We report the palliative effectiveness of a hypofractionated radiotherapy regimen in patients with poor prognosis high grade glioma. Thirty-eight elderly, and/or disabled patients received radiotherapy to a dose of 30 Gy in 6 fractions over 2 weeks to a planning target volume defined by the enhancing tumour and a 2-cm margin. The median survival was 6 months with a 1-year survival rate of 23%. Treatment was without acute toxicity. One month after radiotherapy, functional status, assessed using a verbally administered Barthel index, improved in 38% and remained stable in a further 39% of surviving patients. At 3 months 39% of surviving patients had improved and a further 12% remained stable. We conclude that in the poor prognostic group of patients with high grade glioma hypofractionated partial brain radiotherapy is well tolerated, convenient and provides effective palliation in a proportion of patients. Comparison with conventional radiotherapy or symptomatic care alone require further evaluation in randomised studies.

Activities of Daily Living↗
PubMed1994

Comparison of the effect of heparin and aspirin versus aspirin alone on transient myocardial ischemia and in-hospital prognosis in patients with unstable angina.

OBJECTIVES: This study compared the effects of heparin and aspirin versus aspirin alone on transient myocardial ischemia and in-hospital prognosis in patients with unstable angina. BACKGROUND: Transient myocardial ischemia occurring in patients with unstable angina is associated with an adverse prognosis. Heparin and aspirin are two drugs used frequently in the treatment of this condition, but the effect of combination therapy versus aspirin alone on transient myocardial ischemia is unknown. METHODS: Two hundred eighty-five consecutive patients with unstable angina were randomized to receive either intravenous heparin plus oral aspirin (150 mg once daily) (Group H + A) or aspirin alone (Group A). Patients also received a beta-adrenergic blocking agent, diltiazem and intravenous nitrates. ST segment monitoring was performed for the 1st 48 h of treatment. Patients were followed up for the duration of their in-hospital stay. RESULTS: One hundred fifty-four patients (30 women, mean [+/- SEM] age 58.3 +/- 0.8 years) received heparin and aspirin (Group H + A), and 131 patients (26 women, mean age 60.6 +/- 0.8 years) received aspirin only (Group A). ST segment monitoring (11,622 h) yielded 244 episodes of transient myocardial ischemia of a total duration of 7,819 min. There were no significant differences between the two treatment arms in the number of patients with transient myocardial ischemia (27 [18%] in Group H + A vs. 31 [24%] in Group A), number of episodes (96 in Group H + A vs. 148 in Group A) or total duration of transient myocardial ischemia (2,911 min in Group H + A vs. 4,908 min in Group A). The incidence of in-hospital myocardial infarction or death was significantly higher in patients with transient myocardial ischemia (53% vs. 22%, p < 0.0001). Five of the six deaths occurred in patients with transient myocardial ischemia. Event-free survival from myocardial infarction or death was similar in both treatment groups. Preadmission therapy with aspirin was associated with a lower in-hospital infarction rate (19% vs. 34%, p = 0.01). CONCLUSIONS: The presence of transient myocardial ischemia in patients with unstable angina is associated with a significantly higher incidence of myocardial infarction or death in hospital. Combined therapy with heparin and aspirin compared with aspirin alone makes no difference in the development of these events, nor does it reduce the development of transient myocardial ischemia.

Adult↗
PubMed1994

Biotyping, ribotyping and esterase electrophoresis as epidemiological tools for Acinetobacter baumannii.

An epidemiological survey was carried out over a one-week period to assess the spread of Acinetobacter baumannii in a medical intensive care unit. Fifty strains were isolated from patients colonized or infected by the organism and from a hospital environment. These strains belonged to biotypes 9 or 18. The rRNA gene restriction patterns (using EcoRI and PvuII as restriction endonucleases) and the esterase electrophoretic profiles were determined on 31 strains, using as comparison strain isolates from another intensive care unit of our hospital and from two other French hospitals. Four EcoRI ribotypes, four PvuII ribotypes and six esterase profiles were identified. All biotype 9 strains isolated in our hospital presented the same ribotype after EcoRI digestion, the same ribotype after PvuII digestion and the same zymotype. The same observation was made on most of the biotype 18 strains. Biotyping is an appropriate method for screening of strains, and ribotyping and esterase electrophoresis could be used as additional methods to delineate outbreaks of nosocomial infections caused by A. baumannii.

Acinetobacter↗
PubMed1994

Design and development of portable biofeedback systems for use in oral dysphagia rehabilitation.

The management of dysphagia presents a major problem in the comprehensive rehabilitation of stroke and head injury patients. Dysphagia is a disorder of the swallowing process. Oral dysphagia refers to abnormalities in the oral phase of the swallowing mechanism. The oral phase of the swallowing mechanism is important for the proper triggering of the swallowing reflex. Current techniques in oral dysphagia rehabilitation include oro-motor exercises using tongue depressors and mouth-care swabs. There is thus a need for a better therapeutic method for oral dysphagia. The purpose of this paper is to report the development of audio-visual biofeedback devices for treating oral dysphagia. Portable biofeedback devices rendering feedback of biomechanical parameters characterizing the oral phase were developed and evaluated in preliminary clinical trials. A patient progress index (PPI) was developed and used to quantify the overall patient progress. The devices demonstrated good patient acceptability.

Biofeedback, Psychology↗
PubMed1994

One-stage laparoscopic pelvic lymphadenectomy and radical perineal prostatectomy.

Laparoscopic pelvic lymph node dissection is currently an accepted procedure for staging adenocarcinoma of the prostate. To assess the feasibility and efficacy of performing laparoscopic pelvic lymph node dissection and radical perineal prostatectomy during the same anesthesia, we retrospectively analyzed 98 patients with clinically localized adenocarcinoma of the prostate who were candidates for radical prostatectomy. Of the patients 12 (12%) underwent laparoscopic pelvic lymph node dissection only since they had metastatic disease to the pelvic lymph nodes on frozen section evaluation (the Gleason pathological grade was 2 to 4 in 2 patients, 5 to 7 in 8 and 8 in 2). Of the remaining 86 patients who underwent radical perineal prostatectomy for definitive management 76 (88%) underwent 1-stage radical perineal prostatectomy immediately after laparoscopic pelvic lymph node dissection, while 10 (12%) in the initial stages of our series underwent delayed perineal prostatectomy following laparoscopic pelvic lymph node dissection (2-stage). The average postoperative hospital stay in the 1-stage group was 3.11 days, yet 19 (25%) patients were discharged from the hospital within 48 hours and another 39 (51%) within 72 hours. Thus, 76% of the patients were discharged from the hospital within 72 hours of laparoscopic pelvic lymph node dissection and radical perineal prostatectomy. The advent of laparoscopic pelvic lymph node dissection and radical perineal prostatectomy has found a resurgence at our institutions, with its lower morbidity rate and more rapid return to normal activity for these patients. Based on our results, we recommend laparoscopic pelvic lymph node dissection followed by radical perineal prostatectomy as a 1-stage treatment option for localized adenocarcinoma of the prostate.

Adenocarcinoma↗
PubMed1994

Dependence of Gorlin formula and continuity equation valve areas on transvalvular volume flow rate in valvular aortic stenosis.

BACKGROUND: Valve areas derived by the Gorlin formula have been observed to vary with transvalvular volume flow rate. Continuity equation valve areas calculated from Doppler-echo data have become a widely used alternate index of stenosis severity, but it is unclear whether continuity equation valve areas also vary with volume flow rate. This study was designed to investigate the effects of changing transvalvular volume flow rate on aortic valve areas calculated using both the Gorlin formula and the continuity equation in a model of chronic valvular aortic stenosis. METHODS AND RESULTS: Using a canine model of chronic valvular aortic stenosis in which anatomy and hemodynamics are similar to those of degenerative aortic stenosis, each subject (n = 8) underwent three studies at 2-week intervals. In each study, transvalvular volume flow rates were altered with saline or dobutamine infusion (mean, 10.3 +/- 5.1 flow rates per study). Simultaneous measurements were made of hemodynamics using micromanometer-tipped catheters, of ascending aortic instantaneous volume flow rate using a transit-time flowmeter, and of left ventricular outflow and aortic jet velocity curves using Doppler echocardiography. Valve areas were calculated from the invasive data by the Gorlin equation and from the Doppler-echo data by the continuity equation. In the 24 studies, mean transit-time transvalvular volume flow rate ranged from 80 +/- 33 to 153 +/- 49 mL/min (P < .0001). Comparing minimum to maximum mean volume flow rates, the Gorlin valve area changed from 0.54 +/- 0.22 cm2 to 0.68 +/- 0.21 cm2 (P < .0001), and the continuity equation valve area changed from 0.57 +/- 0.18 cm2 to 0.70 +/- 0.20 cm2 (P < .0001). A strong linear relation was observed between Gorlin valve area and mean transit-time volume flow rate for each study (median, r = .88), but the slope of this relation varied between studies. The Doppler-echo continuity equation valve area had a weaker linear relation with transit-time volume flow rate for each study (median, r = .51). CONCLUSIONS: In this model of chronic valvular aortic stenosis, both Gorlin and continuity equation valve areas were flow-dependent indices of stenosis severity and demonstrated linear relations with transvalvular volume flow rate. The changes in calculated valve area that occur with changes in transvalvular volume flow should be considered when measures of valve area are used to assess the hemodynamic severity of valvular aortic stenosis.

Animals↗