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Biomedical subjects

T Roy

Publications and source records attributed to T Roy.

At least 37 records · Page 2Linked to original sources
PubMed2000

Economic impact of harmonizing medical practices: compliance with clinical practice guidelines in the follow-up of breast cancer in a French Comprehensive Cancer Center.

PURPOSE: The introduction of clinical practice guidelines (CPGs) and the increasing desire to harmonize clinical practices draw attention to the economic impact of these trends. In 1994, CPGs were introduced in a French Comprehensive Cancer Center (Centre Régional Léon Bérard, Lyon). We evaluated the application of these CPGs in addition to the consequences of harmonizing clinical practices with respect to the distribution of resources by specifically analyzing the posttherapeutic follow-up of patients with localized breast cancer. METHODS: A before-and-after analysis of the records of patients who received posttherapeutic follow-up for localized breast cancer as of either 1993 or 1995 was performed. Two hundred records were chosen at random, 100 from 1993 and 100 from 1995. Follow-up was continued for as long as possible and CPG compliance was studied for each year of the follow-up periods. RESULTS: Follow-up that was not CPG-compliant required a significantly greater amount of resources. This difference was due to neither consultations nor mammographies, but was due to other examinations that were systematically performed without any warning signs to justify them. Depending on the follow-up year, noncompliant follow-up cost the Social Security from 2.2 to 3.6 times more than compliant follow-up. A noticeable change in medical practices was observed after the introduction of CPGs in 1994. This was confirmed by a sharp decrease in mean Social Security expenditure per patient of more than one third between 1993 and 1995, regardless of the follow-up year considered. CONCLUSION: In the follow-up of patients with localized breast cancer, a large decrease in costs has been observed along with the evolution of medical practices toward CPG compliance. This finding is probably generalizable to other settings, but there is nothing that proves that it is applicable to other treatment strategies.

Aged↗
PubMed1999

A new way of removing silicone oil from the surface of silicone intraocular lenses.

PURPOSE: This study was performed to ascertain the efficacy of Perfluorhexyl-octan, C14F13H17 (F6H8), in dissolving silicone oil from the surface of silicone intraocular lenses. So far F6H8 is the only solvent of silicone oil that is tolerated by intraocular tissues. MATERIALS AND METHODS: Intraocular silicone lenses (Domilens) were examined after application of small droplets of silicone oil of two different viscosities (AdatoSIL-OL 1000 and 5000) followed by rinsing with F6H8. To allow distinction between silicone oil and F6H8 the silicone oil was stained. Microscopic examination was carried out under video control. RESULTS: One hundred microliters of AdatoSIL-OL 1000 could be easily removed with about 800 microl of F6H8; 50 microl of AdatoSIL-OL 5000 also disappeared after 800 microl of F6H8. A larger drop of the latter oil could not be removed even after application of 2 ml of F6H8. CONCLUSION: Silicone oil 1000 can be easily dissolved by F6H8, whereas silicone oil 5000 is more difficult to remove because of its higher viscosity.

Equipment Contamination↗
PubMed1999

Reliability and validity of a new method of measuring posterior shoulder tightness.

STUDY DESIGN: Repeated measures of shoulder flexibility on nonimpaired subjects and intercollegiate baseball pitchers. OBJECTIVES: To present a new objective method of measuring posterior shoulder tightness, define the intratester and intertester reliability of the measurement, and assess its construct validity. BACKGROUND: Posterior shoulder tightness has been linked to anterior humeral head translation and decreased internal rotation. The reliability of an objective assessment of posterior shoulder tightness has yet to be established in the literature. METHODS AND MEASURES: Five repeat measurements were made using a standardized protocol on 21 nonimpaired subjects to determine intratester reliability. To determine intertester reliability, 2 testers (blinded to their measurement) each performed 1 measurement on 49 shoulders. Twenty-two intercollegiate baseball pitchers were measured once by 1 tester to evaluate the construct validity of the measurement. RESULTS: Measurements of posterior shoulder tightness performed by the same physical therapist had high reliability (ICC dominant = 0.92, nondominant = 0.95). Intertester measures revealed good reliability (ICC = 0.80). Pitchers had reduced dominant arm internal rotation and increased external rotation ROM compared to their other arm whereas nonimpaired subjects had less reduction in external rotation compared to the nondominant arm (pitchers: dominant, 109.7 degrees +/-2.4 degrees, nondominant, 98.9 degrees +/-1.6 degrees; nonimpaired subjects: dominant, 95.9 degrees +/-1.5 degrees, nondominant, 95.2 degrees +/-1.6 degrees) and internal rotation (pitchers: dominant, 50.0+/-2.0 degrees, nondominant, 69.5+/-2.5 degrees; nonimpaired subjects: dominant, 46.4+/-1.3 degrees, nondominant, 50.2+/-1.4 degrees). Pitchers had significantly greater posterior shoulder tightness compared to nonimpaired subjects (pitchers; dominant, 44.9+/-0.8 cm, nondominant, 37.5+/-0.7 cm, nonimpaired subjects; dominant, 32.9+/-0.8 cm, nondominant, 31.4+/-0.8 cm) and manifested a significant correlation between posterior shoulder tightness and internal rotation (r = -0.61) that was not evident in nonimpaired subjects. CONCLUSIONS: Measurement of posterior shoulder tightness using this technique is objective and reliable when done by the same physical therapist. Validity of this measurement is supported from the observation of athletes thought to have tight posterior structures. Further study is needed to determine the relationship of this measurement to patients diagnosed with shoulder impingement syndrome.

Adolescent↗
PubMed1998

Lipid-based delivery systems for improving the bioavailability and lymphatic transport of a poorly water-soluble LTB4 inhibitor.

Ontazolast is a potent inhibitor (IC50 = 1 nm) of calcium ionophore A23187-stimulated leukotriene B4 (LTB4) biosynthesis in human peripheral blood leukocytes. The compound is practically insoluble in water (0.14 microgram/mL) and previous studies in animals have demonstrated extensive presystemic drug clearance through hepatic first-pass metabolism. Bioavailability of a suspension formulation in rats was less than 1%, but increased to approximately 9% when administered as a 20% soybean oil-in-water emulsion. The emulsion formulation and three additional lipid-based formulations were administered by gavage to conscious, minimally restrained rats in a novel, double-cannulated model to determine the effects of formulation on systemic blood absorption and mesenteric lymph transport of ontazolast. The bioavailability of ontazolast was significantly and substantially enhanced by all of the lipid-based formulations. While these formulations also significantly increased the amount of ontazolast transported by the lymph, the total amounts transported were insufficient to account for the improvement in bioavailability, which may be due to the elimination or reduction of the barriers of poor aqueous solubility and slow dissolution to absorption of ontazolast from the gastrointestinal tract, or the effects of lipid on the gastrointestinal membrane permeability, transit time, or metabolism of ontazolast. Semisolid SEDDS formulations, composed of Peceol and Gelucire 44/14, produced bioavailability similar to the emulsion formulation. The total amount of ontazolast transported by the lymph varied directly with the amount of concurrent triglyceride transport and appeared to be favored by formulations that prolong gastric emptying time or promote rapid absorption of ontazolast from the gastrointestinal tract.

Administration, Oral↗
PubMed1998

[Chronic eosinophilic pneumopathy in a black African patient].

The authors report a case of a black African patient who suffers from a chronic eosinophilic pneumonia. In view of the lack of precise reporting in the literature of such a case in black Africans, the initial difficulty of strictly excluding a parasitologic etiology is discussed. From the comparison of paraclinical and clinical data with those of the literature, the authors emphasize the close relationship between asthma and chronic eosinophilic pneumonia and the role of alveolar eosinophils in the physiopathology of that illness.

Adult↗
PubMed1996

Nitric oxide contributes to estrogen-induced vasodilation of the ovine uterine circulation.

Estradiol-17beta (E2beta), a potent vasodilator, has its greatest effects on the uterine vasculature, blood flow (UBF) increasing > or = 10-fold. The mechanism(s) responsible for E2beta-induced vasodilation is unclear. We determined if nitric oxide (NO)-induced increases in cGMP modulate estrogen-induced increases in UBF, and if cyclooxygenase inhibition modifies E2beta responses. Nonpregnant (n = 15) and pregnant (n = 8) ewes had flow probes implanted on main uterine arteries and catheters in branches of the uterine vein and artery bilaterally for blood sampling and infusion of the NO synthase inhibitor L-nitro-arginine methyl ester (L-NAME), respectively. In nonpregnant ewes E2beta (1 microg/kg) caused parallel increases (P < 0.001) in UBF (15+/-3 to 130+/-16 ml/min) and uterine cGMP secretion (23+/-10 to 291+/-38 pmol/min); uterine venous cGMP also rose (4.98+/-1.4 to 9.43+/-3.2 pmol/ml; P < 0.001). Intra-arterial L-NAME partially inhibited increases in UBF dose-dependently (r = 0.66, n = 18, P < 0.003) while completely inhibiting cGMP secretion (P = 0.025). Indomethacin, 2 mg/kg intravenously, did not alter E2beta-induced responses. After E2beta-induced increases in UBF, intraarterial L-NAME partially decreased UBF dose dependently (r = 0.73, n = 46, P < 0.001) while inhibiting cGMP secretion (178+/-48 to 50+/-24 pmol/min; n = 5, P = 0.006); both were reversed by L-arginine. In pregnant ewes, E2beta increased UBF and venous cGMP (9.1+/-0.96 to 13.2+/-0.96 pmol/ml, P < 0.01); however, intraarterial L-NAME decreased basal cGMP secretion 66% (P = 0.02), but not UBF. Acute estrogen-induced increases in UBF are associated with NO-dependent increases in cGMP synthesis, but other mechanisms may also be involved. However, vasodilating prostanoids do not appear to be important. In ovine pregnancy NO is not essential for maintaining uteroplacental vasodilation.

Animals↗
PubMed1994

Comprehensive quality management program for radiation oncology.

A quality management program for both external beam irradiation (electron and photon modes) and brachytherapy (high dose rate (HDR) and low dose rate (LDR) has been developed. The program follows current USA federal regulations for therapeutic administration of by-product materials. After implementation of the program, 54 HDR patients, 36 LDR brachytherapy patients and 311 external beam patients (including 30 stereotactic radiosurgery cases) were treated. The results of this program are presented.

Brachytherapy↗
PubMed1994

Fitting a straight line when both variables are subject to error: pharmaceutical applications.

In many pharmaceutical applications one postulates a linear relationship between variables. The usual linear least-squares methods are appropriate when the values of the independent variable are constants, and the dependent variable is subject to error. When both variables are subject to error, as in assay validation, calibration, and general correlation, the measurement error model (also called errors-in-variables) should be used especially when independent variable error is appreciable. In this paper, the theoretical properties of errors-in-variables methods are demonstrated with examples, and a technique for assessing the variability of parameter estimates without normality assumptions is presented. Robust methods resistant to outliers and not requiring normality assumptions, are also described.

Chemical Phenomena↗
PubMed1994

Unexpected gallbladder cancer with cutaneous seeding after laparoscopic cholecystectomy.

We describe a case of gallbladder carcinoma involving full thickness of the gallbladder wall after laparoscopic cholecystectomy for cholecystitis. Laparotomy for removal of the gallbladder bed and excision of the umbilical cannula site revealed focal residual tumor in the liver bed and microscopic tumor implant in the cannula site. Postoperatively, the patient had radiotherapy of the tumor bed and umbilical scar. Eleven months later, the patient was alive without any evidence of relapse. Excision of the gallbladder bed and laparoscopic scar with or without complementary radiotherapy may be indicated for management of cases in which transmural extension of the unexpected gallbladder carcinoma occurs after laparoscopic cholecystectomy.

Adenocarcinoma↗
PubMed1993

IR-192, low dose rate endobronchial brachytherapy in the treatment of malignant airway obstruction.

PURPOSE: To assess the value of low-dose-rate endobronchial brachytherapy in the treatment of malignant airway obstruction. METHODS AND MATERIALS: Between September 1986 and April 1989, 39 patients with malignant airway obstruction had 49 catheter placements for an afterloading, low-dose-rate Ir-192 endobronchial brachytherapy. A flexible fiberoptic bronchoscope with fluoroscopic guidance was used for positioning. Thirty-eight of 39 (97%) patients completed the prescribed treatments. Ninety-seven percent had received previous external radiation in doses ranging from 36-60 Gy. One patient had metastatic renal cell carcinoma; the remainder had recurrent lung cancer. Endobronchial laser treatments were given to three patients 2-3 weeks prior to endobronchial brachytherapy. All patients were followed until death. The median dose delivered in 48 of the 49 placements was 20 Gy at 1 cm. RESULTS: Follow-up bronchoscopy was performed in 28 (72%) of 39 patients. Of these, 13 (46%) had a complete response, 12 (43%) had a partial response, and 3 (17%) had a minor response. Dyspnea improved in 30 of 37 patients (82%); hemoptysis in 17 of 19 patients (89%); cough in 31 of 39 patients (79%); and postobstructive pneumonia in 21 of 23 patients (92%). The median survival for the entire group was 5 months (range 1-31 months). CONCLUSION: This technique is simple, well-tolerated and offered significant palliation.

Adult↗
PubMed1993

Estimating shelf-life using L1 regression methods.

The shelf-life of a drug is usually determined by fitting the assayed values of drug potency versus time to a linear least-squares model. In least-squares models, the parameters are estimated by minimizing the sum of squares of the residuals. Shelf-life is estimated as the time corresponding to the intersection point of the fitted line and the minimum acceptable per cent or proportion of the initial drug potency. The least-squares method can be seriously affected by outliers, leading to erroneous shelf-life estimates. In this paper, an alternative method, based on minimizing the sum of absolute deviations, was applied to the shelf-life determination problem. The resistance of these L1 based estimates to outliers was demonstrated using a typical stability dataset.

Drug Stability↗
PubMed1993

Pharmacokinetics of nevirapine: initial single-rising-dose study in humans.

Nevirapine, a nonnucleoside inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase, was administered for the first time to humans in a pilot study designed to investigate the pharmacokinetics and tolerance of the drug following single-dose administration to 21 HIV-1-infected individuals. The study followed a parallel design. Different groups of three subjects each were given one of seven dose levels (2.5 to 400 mg) in sequential order, starting with the lowest dose. Each subject received only one dose. Nevirapine was rapidly absorbed at all doses from a tablet formulation. Peak concentrations in plasma were generally achieved within 90 min of dose administration. Secondary peaks were also noted between 3 and 12 h or between 24 and 28 h, the latter being noted mainly in subjects receiving the higher doses. After 24 h, concentrations in plasma declined in a log-linear fashion. The terminal half-life and mean residence time exceeded 24 h in all but one subject, indicating a prolonged disposition time in this population. Both peak concentrations in plasma and areas under the plasma concentration-time curves increased proportionally with increasing dose from 2.5 to 200 mg; however, the increase in the peak concentration in plasma and the area under the plasma concentration-time curve appeared to be less than proportional at the 400-mg dose level in this small number of subjects. This observation may be due to increased clearance or decreased absorption at the highest dose or population differences in absorption or clearance between doses. Studies with a cross-over design are planned to resolve these issues. The pharmacokinetic characteristics of nevirapine are appropriate for once-daily administration. A daily 12.5-mg dose is predicted to achieve trough concentrations in plasma in the range required to totally inhibit replication of wild-type HIV-1 in human T-cell culture.

Acquired Immunodeficiency Syndrome↗