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Biomedical subjects

C George

Publications and source records attributed to C George.

At least 145 records · Page 8Linked to original sources
PubMed1986

Controlled trial of transcutaneous electrical nerve stimulation (TENS) for postoperative pain relief following inguinal herniorrhaphy.

We have evaluated the effect of transcutaneous electrical nerve stimulation (TENS) on postoperative pain following inguinal herniorrhaphy in a prospective randomized controlled trial. Forty male patients undergoing unilateral inguinal herniorrhaphy for the first time were randomized to receive either active or inactive TENS. Electrical stimulation was delivered by electrodes placed along either side of the wound following operation. An identical apparatus, which did not deliver an electrical current, was applied to control patients. Pain was assessed over the first 3 postoperative days by visual analogue pain scores, expiratory peak flow rates and analgesic requirements. There was no difference between the two groups for pain scores, peak flow rates or analgesic requirements and we conclude that TENS as used in this trial does not reduce postoperative pain. However, TENS had considerable patient appeal and many patients believed that it was effective.

Adult↗
PubMed1986

Cognitive functioning in the fragile-X syndrome: a study of intellectual, memory and communication skills.

There may be several cognitive features that characterize fragile-X syndrome in both males and females. Since this study is one of the few that examines noninstitutionalized individuals with the syndrome, future studies of affected individuals should continue to include formal assessment of their cognitive skills. Likewise, the examination in this study of one single family with fragile-X syndrome indicates that further evaluation of verbal, perceptual, memory, language and speech skills is necessary to determine the prevalence of the features described.

Adult↗
PubMed1986

Failure of a microbial assay to reliably predict disease recurrence in a treated periodontitis population receiving regularly scheduled prophylaxes.

The purpose of this study was to evaluate the reliability of differential dark-field microscopy (DDFM) of subgingival bacteria to correctly predict the recurrence of periodontitis in treated patients on 2 different recall schemes. The results are based on data from 51 patients on 3-month recalls (C group) and 39 patients (T group) who received periodontal prophylaxes according to a customized regimen based on DDFM of subgingival bacterial morphotypes. No significant differences were detected in the rate of recurrence of periodontitis between the 2 groups, although the incidence of disease recurrence tended to be greater in the C group. The proportions of spirochetes and motile rods observed at base line, or the average of the values observed at base line, 3 months and 6 months, were compared between subjects with and without disease recurrences. Significantly elevated proportions of these bacterial morphotypes were observed in patients of the T group who demonstrated evidence of disease recurrence during the first year as compared to subjects without disease recurrence. No significant differences could be detected in bacterial morphotypes between patients resistant to disease recurrence and those who developed recurrences at some time during the 3-year period covered by this report. The ability of DDFM of subgingival bacterial morphotypes to predict future disease occurrence was tested for 1- and 3-year periods, in both the C and T groups. The test appears to be reliable only for subjects on the experimental maintenance regimen (group T) and for prediction of disease recurrence for the initial 1-year period.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteria↗
PubMed1985

Endoscopic ultrasonography: a preliminary report.

In order to define normal endoscopic ultrasonographic anatomy with particular emphasis on the pancreas, we studied 25 patients using a prototype ultrasound fiberoptic endoscope (model GF-UM1) and endoscopic ultrasound observation unit (model EU-M1) developed by the Olympus Corporation. We obtained a number of good quality scans of various retroperitoneal structures, and in several cases pancreatic texture and even the pancreatic duct could be appreciated. Differentiation of mucosal from intramural diseases of the hollow gut and from diseases of the retroperitoneal organs can be made by means of endoscopic ultrasonography.

Endoscopes↗
PubMed1985

[Role of erythrocyte deformability in erythrocyte transit time and bioavailability of O2].

The bioavailability of oxygen and its transfer towards all of the cells of the body essentially depends on the flow rate of red blood cells in the capillaries, which often have a smaller diameter than the red cell itself. The authors discuss the results obtained for the mean transit time of erythrocytes, based on microfiltration through artificial polycarbonate capillaries with a diameter of 5 microns, a length of 13 microns and a density of 4.10(5) pores/cm2.

Biological Availability↗
PubMed1984

Volume and planar gated cardiac magnetic resonance imaging: a correlative study of normal anatomy with thallium-201 SPECT and cadaver sections.

Magnetic resonance (MR) gated cardiac imaging was performed in ten subjects using a prototype 0.15-T resistive magnet imaging system. Volume and planar imaging techniques utilizing saturation recovery, proton Tl-weighted relaxation time pulse sequences produced images of the heart and great vessels with exquisite anatomic detail that showed excellent correlation with cadaver sections of the heart. The left ventricular myocardial segments also showed excellent correlation with the thallium-201 cardiac single photon emission computed tomography images. Volume acquisition allowed postprocessing selection of tomographic sections in various orientations to optimize visualization of a particular structure of interest. The excellent spatial and contrast resolution afforded by MR volume imaging, which does not involve the use of ionizing radiation and iodinated contrast material, should assure it a significant role in the diagnostic assessment of the cardiovascular system.

Aorta↗
PubMed1984

Assessment of erythrocyte deformability by constant flow filtration technique: analysis of factors influencing the initial pressure.

When filtering red blood cells (RBC) resuspended into buffer at constant flow, the pressure-time curve is dependent on erythrocyte deformability (E.D) and also on the plugging of pores by RBC or leukocytes (WBC). To understand the influence of these 3 factors, we used an apparatus with: 1) a constant flow syringe (Bioblock) (1.56 ml/mn); 2) a pressure transducer (Statham P23 ID); 3) a recorder (Gould); 4) a 5 micron polycarbonate filter (Nuclepore) housed in a lucite block according to USAMI & al. (1). Resuspensions of RBC from 4 to 14% haematocrit with 0 to 600 WBC/mm3 were investigated. Results indicate that: 1/ The first inflexion point of the pressure-time curve (initial pressure leading to calculation of beta) is related to the RBC's deformability; 2/beta is (in our experimental conditions) dependent on the WBC number; 3/beta seems very sensitive to deformability changes as shown by rapid increases induced by osmolarity changes.

Erythrocytes↗
PubMed1984

Endoscopic ultrasonography: preliminary experience.

Endoscopic ultrasonography was performed in 30 patients using the prototype ultrasound fiberoptic endoscope (Model GF- UM1 , Olympus Corporation) with the objective of developing technique, assessing instrument performance, and familiarization with the capabilities of endoscopic ultrasonography. Insertion of the instrument was accomplished in all patients. There were no complications. Some difficulty was encountered in maneuvering the instrument through relatively narrow areas of the gastrointestinal tract including the pylorus and apex of the duodenal bulb. Diagnostic upper gastrointestinal endoscopy was performed prior to endoscopic ultrasonography using standard forward viewing endoscopes. A variety of normal anatomic structures were noted. Examinations required from 30 to 45 minutes. Images obtained were sharp and clear, although there was some decrease in resolution with depth of display. The advantages and indications for the procedure are not yet established. The procedure might be considered for special purposes such as examination of the pancreas.

Digestive System↗
PubMed1983

The second law as a selection principle: The microscopic theory of dissipative processes in quantum systems.

The second law of thermodynamics, for quantum systems, is formulated, on the microscopic level. As for classical systems, such a formulation is only possible when specific conditions are satisfied (continuous spectrum, nonvanishing of the collision operator, etc.). The unitary dynamical group can then be mapped into two contractive semigroups, reaching equilibrium either for t --> +infinity or for t --> -infinity. The second law appears as a symmetry-breaking selection principle, limiting the observables and density functions to the class that tends to thermodynamic equilibrium in the future (for t --> +infinity). The physical content of the dynamical structure is now displayed in terms of the appropriate semigroup, which is realized through a nonunitary transformation. The superposition principle of quantum mechanics has to be reconsidered as irreversible processes transform pure states into mixtures and unitary transformations are limited by the requirement that entropy remains invariant. In the semigroup representation, interacting fields lead to units that behave incoherently at equilibrium. Inversely, nonequilibrium constraints introduce correlations between these units.

Journal Article↗
PubMed1983

Pentoxifylline and cerebrovascular diseases.

Pentoxifylline is a drug known to increase red cell deformability, thus allowing the 7- to 8-micrometers diameter red cell to flow through the narrowest capillaries of 3-5 micrometers diameter. Red cell deformability is reduced in various forms of cerebrovascular impairment. Pentoxifylline can be effective in these states, not only in restoring red cell deformability, but also on hemodynamic and clinical parameters. Regional blood flow is influenced favorably by the drug. Many double-blind trials advocating its clinical efficacy are reviewed in this paper.

Animals↗
PubMed1983

From Virchow to red cells (the unended quest).

For Virchow vessel wall, coagulability and flow were the three eventual culprits of thrombogenesis. Pharmacological progress in the three fields has not been parallel. Strangely enough they have found possible therapy in the order of their description: first the vessel wall with vasodilators. Then 'coagulability' with anticoagulants, thrombolytics, antiaggregants. It is only more recently that new methods of investigation have allowed assessment and pharmacology of the main determinant of flow in microvessels: red cell deformability.

2,3-Diphosphoglycerate↗
PubMed1983

[Blood microfiltration methods].

Red cell deformability can be approached by filtration through narrow channels either at constant pressure or at constant flow. A very simplified constant pressure method is described, measuring relative flow of 8% hematocrit red cells resuspended in buffer. A constant flow method is also described, using again 8 to 10% hematocrit, which the authors consider as more physiological than the very low hematocrits used by others. Significant results are obtained after incubation with pentoxifylline.

Blood↗