Search PubMed⌕ Search

Biomedical subjects

M LeBlanc

Publications and source records attributed to M LeBlanc.

At least 37 records · Page 2Linked to original sources
PubMed1998

Chemoradiotherapy versus radiotherapy in patients with advanced nasopharyngeal cancer: phase III randomized Intergroup study 0099.

PURPOSE: The Southwest Oncology Group (SWOG) coordinated an Intergroup study with the participation of Radiation Therapy Oncology Group (RTOG), and Eastern Cooperative Oncology Group (ECOG). This randomized phase III trial compared chemoradiotherapy versus radiotherapy alone in patients with nasopharyngeal cancers. MATERIALS AND METHODS: Radiotherapy was administered in both arms: 1.8- to 2.0-Gy/d fractions Monday to Friday for 35 to 39 fractions for a total dose of 70 Gy. The investigational arm received chemotherapy with cisplatin 100 mg/m2 on days 1, 22, and 43 during radiotherapy; postradiotherapy, chemotherapy with cisplatin 80 mg/m2 on day 1 and fluorouracil 1,000 mg/m2/d on days 1 to 4 was administered every 4 weeks for three courses. Patients were stratified by tumor stage, nodal stage, performance status, and histology. RESULTS: Of 193 patients registered, 147 (69 radiotherapy and 78 chemoradiotherapy) were eligible for primary analysis for survival and toxicity. The median progression-free survival (PFS) time was 15 months for eligible patients on the radiotherapy arm and was not reached for the chemo-radiotherapy group. The 3-year PFS rate was 24% versus 69%, respectively (P < .001). The median survival time was 34 months for the radiotherapy group and not reached for the chemo-radiotherapy group, and the 3-year survival rate was 47% versus 78%, respectively (P = .005). One hundred eighty-five patients were included in a secondary analysis for survival. The 3-year survival rate for patients randomized to radiotherapy was 46%, and for the chemoradiotherapy group was 76% (P < .001). CONCLUSION: We conclude that chemoradiotherapy is superior to radiotherapy alone for patients with advanced nasopharyngeal cancers with respect to PFS and overall survival.

Adolescent↗
PubMed1998

The design and development of a gloveless endoskeletal prosthetic hand.

Current prosthetic hands, although functional, have the potential of being improved significantly. We report here the design and development of a novel prosthetic hand that is lighter in weight, less expensive, and more functional than current hands. The new prosthesis features an endoskeleton embedded in self-skinning foam that provides a realistic look and feel and obviates the need for a separate cosmetic glove. The voluntary-closing mechanism offers variable grip strength. Placement of joints at three locations (metacarpophalangeal and proximal and distal interphalangeal) within each of four fingers affords realistic finger movement. High-strength synthetic cable attached to the distal phalanx of each finger is used to effect flexion. A multiposition passive thumb provides both precision and power grips. The new prosthesis can securely grasp objects with various shapes and sizes. Compared to current hands, weight has been reduced by approximately 50%, and cable excursion required for full finger flexion by more than 50%. The new endoskeletal prosthesis requires approximately 12-24% less force input to grasp a variety of everyday objects, largely due to its adaptive grip. Production cost estimates reveal the new prosthesis to be significantly less expensive than current prosthetic hands.

Activities of Daily Living↗
PubMed1997

Follicular lymphomas: do histologic subtypes predict outcome?

There has been a long history of debate as to whether histologic subtypes of follicular lymphoma are associated with unique outcomes. The controversy has been fueled by studies of small patient groups having heterogeneous prognostic factors followed for short intervals, and by a new proposal for the classification of lymphomas (REAL). The current report provides insight into the controversy by using a large group of patients of similar stage and treatment followed for up to 25 years.

Adult↗
PubMed1995

One-year follow-up of 273 infants with birth weights of 700 to 1100 grams after prophylactic treatment of respiratory distress syndrome with synthetic surfactant or air placebo. American Exosurf Neonatal Study Group I.

A single dose of synthetic surfactant was administered prophylactically to premature neonates with birth weights between 700 and 1100 gm. The effects of this treatment on neurodevelopmental, neurologic, and ophthalmologic outcomes, impairments, and general health status were examined during a follow-up evaluation at 1-year adjusted age. The study was a multicenter, parallel, randomized, double-blind comparison of 446 infants who received either air placebo (n = 222) or synthetic surfactant (n = 224). Follow-up evaluations were completed for 82% of surviving infants in both treatment groups. Neurodevelopmental outcome and growth were equivalent in the infants treated with synthetic surfactant and in the infants given air placebo. Impairments occurred in 38% of the infants treated with air placebo compared with 31% of those given synthetic surfactant; the difference was not statistically significant (relative risk 0.809, 95% confidence interval 0.585, 1.119). The incidence of asthma was significantly higher in the group of infants given air placebo (4% vs 10% for surfactant and air placebo, respectively, relative risk 0.391, 95% confidence intervals 0.157, 0.972). Other outcomes, including retinopathy of prematurity, hospital readmissions, surgery, and evidence of chronic lung disease, were not different. Administration of a single prophylactic dose of synthetic surfactant increases survival in infants with birth weights between 700 and 110 gm without increasing the number or proportion of impaired survivors.

Air↗
PubMed1995

Ontogeny and ultradian rhythms of adrenocorticotropin and cortisol in the late-gestation fetal horse.

Fetal maturation and the timing of parturition in both sheep and primates are thought to be controlled by the hypothalamic-pituitary-adrenal axis but little is known about the endocrinology of the equine fetus. We investigated the ontogeny of plasma concentrations of adrenocorticotropic hormone (ACTH), cortisol and corticosteroid binding capacity in the late-gestation fetal horse. We also wished to determine whether there is ultradian rhythmic release of ACTH and cortisol in fetal horses and we compared fetuses to maternal and non-pregnant adult horses. Six fetuses, 278-304 days gestation (term approximately 335), were catheterized and sampled daily until delivery. Mean (+/- S.E.M.) ACTH concentrations increased significantly from 159 +/- 21 to 246 +/- 42 pg/ml over the last 2 days before parturition. Fetal cortisol increased significantly from 3.1 +/- 1.0 to 13.4 +/- 3.7 ng/ml (mean +/- S.E.M.) over the last 9 days before delivery. The slope of regressions for ACTH and cortisol concentrations with respect to time were positive in all subjects and statistically significant in 3 of 6 for ACTH and 5 of 6 for cortisol. Fetal corticosteroid binding capacity declined from 49.5 +/- 20.5 to 16.1 +/- 2.2 ng/ml (mean +/- S.E.M.) over the last 10 days before parturition. However, the greatest changes in ACTH, cortisol and corticosteroid binding capacity occurred very late in gestation, during the last 48 to 72 h before parturition.(ABSTRACT TRUNCATED AT 250 WORDS)

Activity Cycles↗
PubMed1994

Measuring quality and performance of assistive technology: results of a prospective monitoring program.

A crucial need in assistive technology delivery is follow-up to determine device performance and satisfaction from the individual with a disability's perception. As part of an overall research project on technology transfer, this investigation was designed to measure and document service delivery outcomes, first in a pilot study at the Rehabilitation Engineering Center (REC), Lucile Salter Packard Children's Hospital at Stanford (LSPCH) with 60 consumers and then in a replication study in four other service delivery centers providing devices to 103 clients. One hundred sixty-three devices were delivered to 163 consumers by five service delivery centers. The results of this investigation indicate that user feedback can be documented through prospective and standardized data collection forms; outcome measures can be helpful in determining user satisfaction and device performance; user responses, compared with clinician evaluations, are reliable perceptions of device performance; provision of the selected assistive devices was demonstrably positive for the majority of device users; and for those individuals not initiating return visits, the phone-call follow-up provided information that would not have been available otherwise to the service providers.

Adolescent↗
PubMed1994

Oxytocin enhances clearance of radiocolloid from the uterine lumen of reproductively normal mares and mares susceptible to endometritis.

The effects of oxytocin on the percentage of technetium 99m albumin colloid (99mTc-microAA), cleared from the uterine lumen was measured in 13 mares. Scintigraphy was performed during 4 consecutive oestrous cycles, on Day 3 of oestrus during Cycles one and 3 and 48 h after ovulation during Cycles 2 and 4. Oxytocin (20 iu) was given i.v. after the initial scintigraphy image during Cycles 3 and 4. Seven multiparous mares (Group 1) were classified as 'susceptible' and 6 mares (2 nulliparous and 4 multiparous; Group 2) were classified as 'resistant' to endometritis. All mares cleared > 90% of 99mTc-microAA within 30 min of oxytocin injection. When no drug was given, Group 1 mares cleared negligible amounts of radiocolloid (< 5%) and Group 2 mares cleared 50-80%. No mares showed signs of colic after oxytocin administration. It is concluded that oxytocin enhances uterine clearance of radiocolloid and may be useful for treating mares exhibiting impaired uterine clearance.

Animals↗
PubMed1993

The histopathology of uterine leiomyomas following treatment with gonadotropin-releasing hormone analogues.

Gonadotropin-releasing hormone analogues (GnRH agonists) cause pituitary desensitization by downregulation of GnRH receptors, decrease gonadal steroid production, and reduce uterine volume in women with leiomyomas. The purpose of this study was to examine the morphologic changes in uterine leiomyomas associated with GnRH agonist treatment. The study group consisted of 33 patients (mean age, 36.9 years) who presented with infertility, dysmenorrhea, and/or menorrhagia, and who were treated with a GnRH agonist prior to surgery. A control group consisted of 44 premenopausal patients (mean age, 41.5 years) with similar symptomatology who underwent resection of leiomyomas only. In neither group was there any history of recent pregnancy, uterine surgery, or hormone replacement therapy. Microscopic review of all cases was performed without knowledge of the therapeutic history. No differences with respect to mitotic activity, fibrosis, edema, or vascular changes were detected. There is a suggestion that leiomyomas subjected to preoperative GnRH agonist treatment showed increased cellularity (P = .04); necrosis (P < .001) was associated with preoperative GnRH agonist treatment. The reduction of leiomyoma size during GnRH agonist therapy may be due to both ischemic injury and cellular atrophy. Although necrosis of leiomyomas is associated with GnRH agonist treatment, the lack of significant pleomorphism or mitotic activity distinguishes these altered leiomyomas from leiomyosarcomas.

Adult↗
PubMed1992

Proportional hazards and recursive partitioning and amalgamation analyses of the Southwest Oncology Group node-positive adjuvant CMFVP breast cancer data base: a pilot study.

Several putative prognostic factors have been identified in node-positive breast cancer patients, but their importance needs to be clarified in a uniformly treated population. The objectives of this investigation were: 1) to describe the characteristics of a uniformly treated node-positive data base; 2) to use proportional hazards (Cox) and recursive partitioning and amalgamation (RPA) multivariate models to assess the importance of potential prognostic factors for disease-free and for overall survival; and 3) to define prognostic groups with different disease-free survival and survival outcomes with RPA. A data base of 768 node-positive patients enrolled on 1-year adjuvant CMFVP arms of four SWOG trials was formed. Variables were number of positive nodes, age, age at menopause, menopausal status, ER status, ER and PgR levels (for RPA only), tumor size, race, breast cancer in mother, and obesity index. Independent predictors of both disease-free and overall survival in the Cox models were: number of positive nodes (4-6 worse than 1-3, and better than greater than 6); the age/menopause category (age greater than or equal to 35/premenopausal better than age less than 35/premenopausal and better than postmenopausal); and ER status (patients on ER-negative study worse than others). The RPA for disease-free survival defined four subgroups based on nodes, menopausal status, tumor size, and age at menopause (5-year recurrence-free rates = 73%, 52%, 38%, and 15%). The RPA for survival found four prognostic groups, defined only by the number of positive nodes and ER and PgR levels (5-year survivals = 91%, 72%, 56%, and 37%). Both RPAs suggested interesting refinements of the results of the Cox models. In the RPA for disease-free survival, best node cutoffs differed by menopausal status, tumor size was important only in postmenopausal patients with few positive nodes, and age at menopause emerged as an independent predictor of recurrence potential. And, the RPA for survival showed that node cutoffs differed according to ER level. Thus, these analyses underscore the value of simple, clinically available prognostic factors and suggest the possible need to reconsider the definition of good and poor risk patient groups in future adjuvant trial design.

Adult↗
PubMed1992

Controlled trial of a single dose of synthetic surfactant at birth in premature infants weighing 500 to 699 grams. The American Exosurf Neonatal Study Group I.

In a multicenter, double-blind, placebo-controlled trial conducted at 23 hospitals in the United States, a single prophylactic 5 ml/kg dose of a synthetic surfactant (Exosurf Neonatal) or air placebo was administered shortly after birth to 215 infants with birth weights of 500 to 699 gm. Despite stratification at entry by birth weight and gender, by chance female infants predominated in the air placebo group and male infants predominated in the surfactant group. Among infants receiving synthetic surfactant, improvements in oxygen requirements were significant at 2 hours after birth (p = 0.014) and persisted for 3 days (p = 0.001); improvements in the alveolar-arterial partial pressure of oxygen gradient were significant at 6 hours after birth (p = 0.01) and persisted for 3 days (p = 0.008). Improvements in mean airway pressure were not significant at 2 or at 6 hours after birth (p = 0.622 and 0.083, respectively), but became significant thereafter and persisted for 3 days (p = 0.002). Pneumothorax was reduced by slightly more than half (25 vs 11; p = 0.014); death from respiratory distress syndrome (RDS) was also reduced (26 vs 15; p = 0.046). Overall neonatal mortality, however, was not significantly reduced (58 vs 46; p = 0.102). Other complications of RDS and prematurity were not altered, except that pulmonary hemorrhage occurred significantly more frequently in infants receiving synthetic surfactant (2 vs 12; p = 0.006). These findings indicate that a single prophylactic dose of synthetic surfactant in infants weighing 500 to 699 gm at birth improves lung function, incidence of air leak, and death from RDS but not overall mortality. The only safety problem identified was an increase in pulmonary hemorrhage.

Bronchopulmonary Dysplasia↗
PubMed1992

Relative risk trees for censored survival data.

A method is developed for obtaining tree-structured relative risk estimates for censored survival data. The first step of a full likelihood estimation procedure is used in a recursive partitioning algorithm that adopts most aspects of the widely used Classification and Regression Tree (CART) algorithm of Breiman et al. (1984, Classification and Regression Trees, Belmont, California: Wadsworth). The performance of the technique is investigated through stimulation and compared to the tree-structured survival methods proposed by Davis and Anderson (1989, Statistics in Medicine 8, 947-961) and Therneau, Grambsch, and Fleming (1990, Biometrika 77, 147-160).

Age Factors↗
PubMed1991

Disruptive boys with stable and unstable high fighting behavior patterns during junior elementary school.

Boys' fighting was assessed at ages six, eight, and nine. The boys (N = 69) had been selected from the 30% most disruptive children in kindergartens from low socioeconomic neighborhoods. Twenty-three percent of these disruptive boys were rated as high fighters on three assessments ("stable high fighters"), and 28% were rated as high fighters on two of the three assessments ("variable high fighters"). Forty-two percent were rated as high fighters only one out of three assessments ("occasional high fighters") and 7% were never rated as high fighters. Only high fighting in two successive years significantly increased the risk of being rated a high fighter in a following year. At age 10, stable high fighters (high fighters at ages 6, 8, 9) were perceived by teachers, peers, mothers, and the boys themselves as more disruptive and more antisocial than occasional high fighters. These results show an impressive self-other agreement in boys who have adopted a physically aggressive life style from an early age. The three groups did not differ on individual family demographic characteristics, but stable high fighters had a higher mean on an index of family socioeconomic disadvantage. Results indicate that the aggression scales which include only a few physical aggression items and many disruptive items (oppositional behavior, rejection, hyperactivity, inattention, etc.) probably aggregate two kinds of disruptive boys, the high-frequency fighters at high risk for stable disruptive, physically aggressive, and antisocial behaviors, and the disruptive low-frequency fighters who are at a lower risk of stable disruptive behavior and at a lower risk of early antisocial behavior.

Aggression↗
PubMed1991

Clinical trials and quality control: checkpoints in the provision of assistive technology.

Clinical trials and quality control measures are characterized by evaluation of assistive technology by users, and feedback to providers for the purpose of improving devices or service delivery. These processes recognize that consumer satisfaction is an important measure of device and service delivery effectiveness. In this article, types of clinical trials are reviewed, and both prospective and retrospective methods of quality control are presented. The authors take the position that rehabilitation engineering centers providing customized devices and adapted technology should implement quality control measures in order to improve services to their clients.

Clinical Trials as Topic↗
PubMed1991

Survival determinants in extensive-stage non-small-cell lung cancer: the Southwest Oncology Group experience.

We analyzed the 2,531-patient Southwest Oncology Group extensive-stage non-small-cell lung cancer (ENSCLC) data base from 1974 to 1988 to (1) assess the interactions of host- or tumor-related prognostic factors and therapy using Cox modeling and recursive partitioning and amalgamation (RPA) to determine whether each independently predicts outcome, and (2) use RPA to define prognostic subsets with different survival potentials. Good performance status (PS), female sex, and age greater than or equal to 70 years were significant independent predictors in a Cox model applied to the entire population. In a second Cox model for patients with good PS enrolled on recent studies, hemoglobin level greater than or equal to 11.0 g/dL, normal lactate dehydrogenase (LDH), normal calcium, and a single metastatic site were significant favorable factors. The use of cisplatin was an additional independent predictor of improved outcome in both Cox models after adjustments for year of accrual and all prognostic variables. The favorable effect of cisplatin was observed in each of six RPA-derived subgroups from the entire population. A second RPA of 904 patients from recent trials (nearly all received cisplatin-based therapy) resulted in three distinct prognostic subsets based on PS, age, hemoglobin, and LDH; greater than or equal to 1-year survivals were 27%, 16%, and 6% (P less than .0001). The best survival occurred for patients with a good PS who had a hemoglobin level greater than or equal to 11 g/dL and who were older than 47 years. This analysis suggests that although several factors were independent variables in the Cox models, three important prognostic subgroups were easily defined through RPA. Together with other analyses, our results suggest the need to modify the stage IV category in NSCLC.

Adult↗
PubMed1991

Identification and opsonic activity of immunoglobulins recognizing Streptococcus zooepidemicus antigens in uterine fluids of mares.

A direct ELISA was used to measure immunoglobulin (Ig) isotypes G, Gt, A, and M recognizing Streptococcus zooepidemicus epitopes in uterine lavage fluids collected during the early post ovulatory period. A S. zooepidemicus isolate, used as the plate antigen in this assay, was inoculated into the uteri of 8 mares (3 resistant and 5 susceptible to endometritis) at oestrus prior to ovulation during Oestrous Cycles 1, 3 and 5. Resistant mares aged 2-5 years were nulliparous, with clinically normal reproductive tracts as determined by physical examination, bacteriological culture of the uterus, and endometrial biopsy. Susceptible, pluriparous mares, aged 16-24 years, had histories of endometritis and infertility and had chronic endometrial inflammatory changes detected by uterine biopsy. On Post ovulation Day 3 during Oestrous Cycle 1, on the day of ovulation during Oestrous Cycle 3 and on Post Ovulation Day 5 during Oestrous Cycle 5, uterine swab specimens were obtained for bacteriological culture and the uterus was irrigated with 50 ml sterile physiological saline solution containing tracer amounts of 125I-labelled human serum albumin (HSA). The titre of each Ig isotype was determined and the amount in uterine effluents was calculated from the dilution of the 125I-HSA. Total IgG concentration in uterine effluents was measured by radial immunodiffusion. Uterine fluids, either unheated or heated 30 min at 56 degrees C, were used to opsonize the S. zooepidemicus isolate in an assay of luminol-enhanced neutrophil chemiluminescence (CL). Mean peak CL generated was compared with CL generated by a control serum. Streptococcus zooepidemicus was isolated from 10 of 15 (67%) uterine specimens from susceptible mares.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Current evaluation of hydraulics to replace the cable force transmission system for body-powered upper-limb prostheses.

Present body-powered upper-limb prostheses use a cable control system employing World War II aircraft technology to transmit force from the body to the prosthesis for operation. The cable and associated hardware are located outside the prosthesis. Because individuals with arm amputations want prostheses that are natural looking with a smooth, soft outer surface, a design and development project was undertaken to replace the cable system with hydraulics located inside the prosthesis. Three different hydraulic transmission systems were built for evaluation, and other possibilities were explored. Results indicate that a hydraulic force transmission system remains an unmet challenge as a practical replacement for the cable system. The author was unable to develop a hydraulic system that meets the necessary dynamic requirements and is acceptable in size and appearance.

Amputees↗