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Biomedical subjects

S Tavares

Publications and source records attributed to S Tavares.

14 recordsLinked to original sources
PubMed2002

A biomechanical study of four different meniscal repair systems, comparing pull-out strengths and gapping under cyclic loading.

Most studies comparing the biomechanical properties of different meniscal repair systems have simply investigated load to failure. Meniscal tissue is highly anisotropic, and far weaker under tension in the radial direction. Radially oriented loading to failure may not therefore be the most physiologically relevant in vitro test for repair of circumferential tears, and determining gapping across repair sites under cyclical loading at lower loads may be of greater importance. Using bovine menisci, vertical circumferential incisions were repaired using a simple vertical 2-0 PDS suture, Meniscal Arrow, Meniscal Fastener or T-Fix. Repairs were tested by simple loading to failure in a materials testing machine, and by cyclic loading between 5 and 10 N for 25 cycles. Initial gapping across the repairs was measured using a digital micrometer, and the increase in gapping under cyclic loading measured using a Differential Voltage Reluctance Transducer. The mean loads to failure for each of the repair groups were: sutures 72.7 N, Arrows 34.2 N, Fasteners 40.8 N and T-Fix 49.1 N. The load to failure was significantly greater with sutures than with Arrows or Fasteners. The mean gapping across the repairs for each of the repair groups after 25 loading cycles were: sutures 3.29 mm, Arrows 2.18 mm, Fasteners 3.99 mm and T-Fix 3.47 mm. The mean gapping was significantly less with Arrows than with Sutures, Fasteners or T-Fix. These results confirm that meniscal repair by suturing gives the highest load to failure, but show that Arrows give superior hold under lower loads, with the least gapping across repairs under cyclic loading of the four methods tested.

Animals↗
PubMed1999

Sexual behavior in sleep, sleepwalking and possible REM behavior disorder: a case report.

Seven cases of sexual behavior during sleep (SBS) have been recently reported. The subjects had histories of behavioral parasomnias as well as positive family histories of parasomnia. A 27 year-old man with a history of sexual behavior during sleep was reported. His sleep history disclosed sleepwalking (SW) since 9 years of age. He also developed episodes of highly disruptive and violent nocturnal behavior with dream enactment at age 20 years, which often resulted in physical injuries either to himself or his wife and infant. His wife also reported episodes of amnestic sexual behavior that began 4 years before referral. During the episodes, the patient typically procured his wife, achieving complete sexual intercourse with total amnesia. Physical and neurological diagnostic workups were unremarkable. Family history disclosed sleepwalking in his brother. He was put on 2mg/day of bedtime clonazepam with a remarkable clinical improvement. This case involves either the combination of violent and non-violent sleepwalking with SBS, or the superimposition of presumed REM sleep behavior disorder (RBD) on top of preexisting SW in a man who also developed SBS in adulthood. Thus, this is a case report of probable parasomnia overlap syndrome.

Adult↗
PubMed1990

Acute reversal of flunitrazepam effects by Ro 15-1788 and Ro 15-3505: inverse agonism, tolerance, and rebound.

A phase 1 double blind crossover comparison of a new benzodiazepine antagonist (Ro 15-3505) with Ro 15-1788 and placebo, in the reversal of sedative and psychophysiological effects of single IV doses of flunitrazepam (2 mg), was carried out in 12 normal volunteers. The antagonists were equally effective, leading to full reversal of all effects with a potency ratio of approximately 2.5 mg Ro 15-1788 for 1 mg Ro 15-3505. Inverse agonism, in the form of unpleasant feelings and symptoms, was reported by all subjects following Ro 15-3505 but none after Ro 15-1788. Adaptational phenomena such as acute tolerance and rebound of sedative effects of flunitrazepam were also detected and their potential implications are discussed.

Adult↗
PubMed1984

Management of penetrating cardiac injuries: the role of emergency room thoracotomy.

Sixty-four consecutive patients with penetrating cardiac injuries were treated between January, 1977, and January, 1983, at the University of Maryland Hospital. Twenty-eight patients had major associated injuries of other organs. The patients were divided into groups according to their clinical status on arrival. An aggressive approach was utilized including early emergency room (ER) thoracotomy for "lifeless" or deteriorating patients. Three patients required immediate cardiopulmonary bypass for repair of their injuries. Twenty-one (57%) of the 37 patients undergoing ER thoracotomy survived; most of the deaths occurred in patients arriving "lifeless" from gunshot wounds. Twenty-four (89%) of the 27 patients who were in stable enough condition to undergo initial repair in the operating room (OR) survived. Overall survival was 45 patients (70%). Though superficial wound infections developed in 18 patients, there were no deep or systemic infections. None of the survivors sustained severe neurological sequelae. Five patients underwent late reoperations for closure of a ventricular septal defect (2), mitral valve replacement (1), and pericardiectomy (2) with no deaths. Though repair of penetrating cardiac injuries should preferably be carried out in the OR, immediate thoracotomy for "lifeless" or deteriorating patients can be performed in the ER with a low incidence of direct surgical complications and with high patient survival.

Adolescent↗
PubMed1984

Subclavian flap repair of coarctation of the aorta in neonates. Realization of growth potential?

The subclavian flap repair for coarctation of the aorta allows potential for growth by utilizing autogenous tissue. Although well documented in young children, its promise in the tiny neonate warrants further evaluation. Since August, 1979, 29 patients, including 24 infants, have undergone subclavian flap repair at the University of Maryland Hospital. Weights ranged from 1.4 to 5 kg (mean 3.2 kg). All patients less than 6 months old had associated intracardiac defects and were in severe congestive failure. Fifteen responded to preoperative prostaglandin infusions. The overall early mortality was 14%; among the neonates it was 21%; and among those operated upon within the first week of life, 33%. There was one intraoperative death among the eight patients who underwent simultaneous pulmonary artery banding. There were no deaths among patients older than 5 days at operation. Four of the five neonates who died had some variant of hypoplastic left heart syndrome, with severe stenosis or atresia of the systemic atrioventricular valve, critical aortic stenosis, or hypoplastic left ventricle. Twenty-two survivors continue to do well up to 3.7 years postoperatively (mean follow-up 26 months). At follow-up all patients are normotensive with brisk lower extremity pulses. Patients now weigh 1.3 to 6.9 (mean 2.3) times their operative weight, and only one patient has a measured arm-to-leg gradient greater than 10 mm Hg (mean gradient 3.7 mm Hg). Seven of the neonates have undergone repeat catheterization, and all had satisfactory growth of the subclavian flap segment of repair and no gradient. Two older patients (3 and 4 years old at operation) have undergone exercise testing 3.7 years after repair, with peak exercise gradients of only 7 and 15 mm Hg. We therefore continue to utilize this technique for the treatment of coarctation even in tiny neonates.

Aortic Coarctation↗
PubMed1983

Migration of Kim-Ray Greenfield umbrella to the heart.

We have described a case of migration of a Kim-Ray Greenfield umbrella from the inferior vena cava to the heart for unknown reason. The umbrella was surgically removed and the patient recovered fully. This complication has not been previously reported. Despite this complication, we believe that the Kim-Ray Greenfield umbrella, when placed with particular attention to technique, effectively prevents pulmonary emboli and offers minimal associated morbidity.

Aged↗
PubMedDate not supplied

Mandibular-Lingual Repositioning Device--MLRD: preliminary results of 8 patients with obstructive sleep apnea syndrome--OSAS.

Dental devices have been employed in the treatment of snoring and obstructive sleep apnea syndrome (OSAS) of mild to moderate degrees. The authors disclose the preliminary results in 8 patients with clinically diagnosed obstructive sleep apnea polisomnographically confirmed and treated with a dental device (Mandibular-Lingual Repositioning Device--MLRD) developed by one of the authors (RCB). Cephalometrics was performed before usage of MLRD, Epworth Sleepiness Scale (ESS) tests were conducted before and after the MLRD and a questionnaire that subjectively qualified the Overall Subjective Improvement of the patient (OSI) was filled out. The tests were repeated 4 weeks after the application of the MLRD. The average subjective overall improvement was 73.75% and the Epworth Sleepiness Scale was 13.88 (pre-MLRD) and 6.63 (post-MLRD) representing a significant statistical variation (p = 0.05). The authors discuss probable factors involved in the improvement of the subjective measurements of excessive sleepiness.

Body Weight↗
PubMedDate not supplied

Excessive somnolence.

Excessive somnolence can be quite a incapacitating manifestation, and is frequently neglected by physicians and patients. This article reviews the determinant factors, the evaluation and quantification of diurnal somnolence, and the description and treatment of the main causes of excessive somnolence.

Disorders of Excessive Somnolence↗
PubMedDate not supplied

[Rolandic epilepsy. An analysis of the clinical and electrophysiological characteristics, treatment and prognosis in 87 patients].

INTRODUCTION: Rolandic epilepsy is the most common epileptic syndrome in infancy. It usually has a favourable prognosis and seizures disappear during the teenage years. AIMS: The aim of this study was to describe a sample of children diagnosed with rolandic epilepsy in clinical, electrophysiological and imaging terms. We also intend to compare the results obtained with those described in the literature. PATIENTS AND METHODS: We conducted a retrospective, descriptive study of the children diagnosed with rolandic epilepsy who had been submitted to a follow-up at the Neuropaediatrics Unit at the HGSA since 1989. Children who were less than 2 years old when they suffered their first seizures or who had abnormal neurological/imaging examinations were excluded. Two groups were defined (typical and atypical), several variables were characterised and these were then analysed statistically. RESULTS: A total of 87 children (51 males) were included in this study, their mean age being 13.6 years. The population was divided into two groups: A (typical cases; n = 69) and B (atypical cases; n = 18). The mean age at the onset of seizures was 6.2 and 6 years for groups A and B, respectively. The predominant type of seizures was simple partial for group A and complex partial for group B; they were mainly sporadic and nocturnal in both groups. Medication was administered to 51 (73.9%) of the children in group A, with a good response in 78.4% of them; 13 members of group B (72.2%) received medication, with a positive response in 76.9% of them. CONCLUSIONS: Rolandic epilepsy has a broad clinical spectrum and usually courses with normal psychomotor development, but may coexist with learning disabilities. In this study, no significant differences were found between the typical and atypical forms of presentation, as far as their progress and response to treatment are concerned.

Adolescent↗