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Biomedical subjects

R A Weber

Publications and source records attributed to R A Weber.

16 recordsLinked to original sources
PubMed1999

Frozen section analysis in the management of skin cancers.

Frozen section analysis is used routinely to ensure complete removal of basal cell and squamous cell carcinomas of the skin, but the current emphasis on controlling costs raises the question as to which lesions should be evaluated with frozen section histology. A retrospective study of the clinical records and pathological reports of 51 patients selected randomly from a total of 225 patients was undertaken to determine the overall impact of frozen section analysis on the surgical management of skin cancers at this institution. The results indicate that frozen section analysis was performed on 76% of the 277 lesions evaluated, and that the results of frozen section examination were 91.1% accurate in detecting the presence or absence of tumor involvement at the surgical margins. The data also showed that the surgeons were able to estimate the margin of the skin tumor clinically and remove it entirely during the first excision 91.1% of the time. The lesions that had not been removed completely with the initial excision were those located on the periorbital region, forehead, and cheeks; were recurrent lesions; or were lesions that required more involved reconstruction than primary closure. This study shows that frozen section analysis is a valuable tool in selected situations, but routine use is not indicated for the majority of basal and squamous cell carcinomas of the skin.

Aged↗
PubMed1997

Flexor carpi radialis approach for carpal tunnel release.

A technique for dividing the transverse carpal ligament has been developed in order to decrease the incidence of pillar pain. The carpal ligament splits around the flexor carpi radialis (FCR) tendon into two leaves as it approaches its radial attachments. The new approach uses the FCR as a guide to divide these attachments under direct visualization, thereby releasing the carpal tunnel. This technique has been used on 87 hands, with 79 (91%) obtaining complete or partial relief of preoperative symptoms. Pillar tenderness resolved quickly and there were few complications. The FCR approach to carpal tunnel release couples the advantages of direct visualization of the carpal canal contents with the decreased disruption of palmar skin and soft tissues, thereby reducing pillar pain without increasing the risk of surgical complications.

Adult↗
PubMed1997

Effect of water temperature on skin wrinkling.

Determining the status of peripheral innervation can be difficult in certain patients. The phenomenon of skin wrinkling has been shown to be a reliable indicator of gross nerve function. This study examines the effect of various water temperatures on the time to skin wrinkling. The optimal temperature for testing hands is 40 degrees C and skin wrinkling should occur in approximately 3.5 minutes.

Adult↗
PubMed1996

Functional evaluation of gap vs. abutment repair of peripheral nerves in the rat.

Various expressions of nerve regeneration specificity (tissue, target, and end-organ) have been demonstrated histologically, but the influence of nerve regeneration specificity on functional outcome remains to be investigated. Specificity expression appears to be dependent, to some extent, on the distance between the proximal and distal nerve stumps. Regeneration specificity is inhibited by end-to-end alignment. This study examined the effect of gap distance repair on the return of rat hind-limb function, as measured by the sciatic function index (SFI). Sixty-four Sprague-Dawley rats were randomized into three groups: 0-mm gap (abutment), 2-mm gap, and 5-mm gap repair. The sciatic nerve was divided and secured in a Silastic conduit to maintain the gap length. The SFI was measured preoperatively and then at postoperative weeks 2, 4, 8, 12, 16, and 20. Results showed no significant difference in functional return between the abutment and the two gap groups at any time period (SFI at 20 weeks = -73.9, 0 mm; -73.5 2 mm; -75.2, 5mm; p = 0.90). This lack of difference in functional outcomes suggested an insignificant functional influence of regeneration specificity within single chamber conduits. The study also demonstrated that small gaps between nerve ends within a conduit yielded functional results equal to end-to-end repair of rat sciatic nerves.

Anastomosis, Surgical↗
PubMed1995

Skin paddle salvage in the fibula osteocutaneous free flap with secondary skin paddle vascular anastomosis.

The fibular osteocutaneous free flap has become a popular choice for the reconstruction of bone and skin defects. A potential drawback has been the reported unreliability of the skin paddle. Previous studies have emphasized total loss of the overlying skin paddle, if the expected perforating vessels are not present either in the intermuscular septum or in the soleus. Two cases are presented in which the skin paddle was found to be supplied by vessels arising from the proximal peroneal artery. there were no intraseptal or intramuscular vessels in the osteocutaneous septum which connected to the overlying skin paddle. The skin island was salvaged by performing independent microsurgical anastomoses of the fibular graft and the skin paddle. Both patients had complete survival of the fibula and overlying skin paddle.

Aged↗
PubMed1994

Radial keratotomy in patients with atypical inferior steepening.

Using corneal topography we screened 1,368 consecutive eyes that had radial keratotomy from November 1991 through April 1993. Fourteen eyes in nine patients exhibited topographic patterns consistent with "keratoconus suspect" status, but only one had atypical clinical findings. At four to 19 months postoperatively, refraction and uncorrected visual acuity improved in all eyes. Eight eyes gained best corrected visual acuity. To date, all 14 eyes appear to be stable, with no radial-keratotomy-related complications.

Adolescent↗
PubMed1993

Autotomy and the sciatic functional index.

The rat sciatic nerve serves as a good model of nerve regeneration and, as such, is often used in investigations of nerve repair. After transection of the sciatic nerve, rodents frequently scratch and bite their anesthetic foot, resulting in amputation of one or more toes. This is termed autotomy or autophagy. When these rats are part of a study using the sciatic functional index (SFI), autotomy results in unusable data, since necessary foot landmarks have been removed. It would be helpful, therefore, to be familiar with the phenomenon of autotomy and to know which rats are least likely to mutilate themselves. In our experiment involving 64 rats in which the sciatic nerve was transected and repaired, we found that female Sprague-Dawley rats were significantly less likely to perform autotomy than males (33% vs. 65%, P = .04). In addition, we noted that two-thirds of the autotomies that occurred did so by postoperative week 4 and that tabasco sauce did not decrease this activity. We present our experience and a survey of the literature on autotomy and the SFI.

Animals↗
PubMed1993

Convoys of social support: an intergenerational analysis.

Within the Convoy Model, social networks are viewed as dynamic hierarchic structures surrounding the individual throughout life. As a step toward empirical definition of convoy structure and function across the life span, a bicultural sample (N = 159) of young adult women, their mothers, and their grandmothers were queried. Comparable results were obtained across generations and cultures with regard to network size, the amount of support provided by the network, and the nomination of close family members as primary sources of support. However, there was a marked shift across generations in the balance of familial versus friendship relations. Younger persons included fewer family members and more friends in their networks, and they received more support from friends. These cross-sectional results are consistent with the Convoy Model and suggest that longitudinal research is warranted.

Adult↗
PubMed1993

A human factors analysis of ADL activities: a capability-demand approach.

Older adults frequently encounter difficulties performing daily living activities. Often times these difficulties arise because environmental demands create barriers which hinder task performance. Currently, there is little empirical data that relate environmental demands to functional capabilities of older adults. The concepts and methods of Human Factors Engineering can be used to accomplish this goal. Human Factors views task performance within a systems context and maintains that successful task performance is dependent on a match between task demands and human capabilities. This article will discuss how Human Factors methodologies can be used to analyze problems encountered by older adults performing routine activities. Data from a study concerned with identifying physiological demands associated with personal and instrumental activities of daily living will be used to demonstrate the utility of using this approach.

Activities of Daily Living↗
PubMed1993

Crotalidae envenomation in children.

Poisonous snakebites cause a severe envenomation syndrome in children, yet treatment remains controversial. Sixty-seven patients were treated for poisonous snakebites at our institution between 1975 and 1990; 18 were children < or = 12 years old. There were 13 rattlesnake bites, 4 copperhead bites, and 1 unidentified bite. Initial management included intravenous fluids and antibiotic administration, laboratory studies, tetanus prophylaxis, affected limb elevation, and a limited excision of the bite site in the emergency room. Antivenin was administered only if signs of systemic involvement such as shock, coagulopathy, gastrointestinal cramping, or neurological involvement were present. Children developed systemic involvement 72% of the time, 9 children (50%) developed coagulopathy. Consequently, 11 (61%) children received antivenin. The dose of antivenin they received was 3.2 ml/kg and the children tolerated it well with only 36% of them demonstrating adverse reactions to the antivenin. Clinically, the pediatric patients demonstrated signs and symptoms of a fulminant envenomation syndrome (8 days, average hospital stay), yet, they had a good eventual outcome. Only 11% of children reported long-term morbidity. No deaths occurred and 100% of patients were able to return to full preinjury activities. We conclude that Crotalidae envenomation in children is a serious disease and warrants hospitalization, early surgical involvement, and frequent use of antivenin.

Animals↗
PubMed1991

Poisonous snakebite in central Texas. Possible indicators for antivenin treatment.

Sixty-seven patients hospitalized for poisonous snakebite between 1975 and 1990 were managed by elevation, tetanus prophylaxis, intravenous fluids and antibiotics, and often by a limited excision of the bite site in the Emergency Department, with sequential laboratory studies as needed. Antivenin was used for systemic envenomation, and 23 of the 67 patients (34%) received 133 vials. Thirteen of the twenty-three patients (56%) had adverse reactions to the antivenin. Two significant observations arose. First age was an indicator. Eleven of eighteen patients 12 years or younger (61%) received antivenin, whereas 12 of 49 patients older than 12 years (24%) received antivenin (p = 0.0085, Fisher's exact test). Second species of snake was an indicator. Sixty-two snakes were identified (93%). Of 39 rattlesnake (Crotalus and Sistrurus) bites, 20 patients received antivenin (53%), but of 23 copperhead and water moccasin (Agkistrodon) bites, only three patients (12.5%) received antivenin (p = 0.0025). Antivenin may be indicated for use in systemic rattlesnake envenomation, especially in younger patients.

Adolescent↗
PubMed1990

Older adults and daily living task profiles.

This paper describes data generated from a comprehensive study in which human factors techniques were applied to the analysis of 25 personal and instrumental activities of daily living (ADLs) performed by 60 older adults (age 55 to 93 years) living in the community. Demand profiles generated from task analysis of video-taped ADLs identify the demands inherent in task activities and the objects and environments associated with them. Examples of four different approaches to examine ADL performance using demand profiles are presented: global descriptions of demands across all ADL tasks, task component profiles, task-specific profiles, and action profiles.

Activities of Daily Living↗
PubMed1988

Helicopter transport of patients during acute myocardial infarction.

Initial experience with a regional system of emergency helicopter transport of patients with acute myocardial infarction (AMI) referred for emergent cardiac catheterization and percutaneous transluminal coronary angioplasty (PTCA) is described. Two hundred fifty patients with AMI were transported from within a 150-mile radius to Duke University Medical Center over a 15-month period. All patients were within 12 hours of onset of symptoms. Thrombolytic therapy was administered to 240 (96%) patients (72% before or in-flight). The time to administration of thrombolytic therapy ranged from 30 to 120 minutes (median 180), while the time to arrival in the interventional catheterization laboratory ranged from 105 to 815 minutes (median 300). The flight time was 12 to 77 minutes (median 31). Most patients had 1- or 2-vessel coronary artery disease; the baseline ejection fraction ranged from 27 to 70% (median 42). Transient hypotension was the most common complication both pre-flight and in-flight. Third-degree atrioventricular block and nonsustained ventricular tachycardia were the next most common complications. Ventricular fibrillation or sustained ventricular tachycardia occurred before takeoff in 38 patients (15%). No patients had ventricular fibrillation, asystole or respiratory arrest during transport. Fluid boluses for hypotension were the most common intervention. Five patients required cardiopulmonary resuscitation in-flight; 3 before lift-off and 2 required a brief period of cardiopulmonary resuscitation during sustained ventricular tachycardia. Fourteen patients had pressor therapy, military antishock trousers or both to maintain adequate blood pressure. Neither cardioversion, defibrillation nor intubation were performed in-flight. Thus, inflight complications are infrequent and can be managed en route to an intervention center.(ABSTRACT TRUNCATED AT 250 WORDS)

Aircraft↗
PubMedDate not supplied

Measuring performance of a half-mask respirator in a styrene environment.

A workplace protection factor (WPF) study was conducted with a half-mask air-purifying respirator during fiber glass boat production. Styrene was the measured analyte, and the geometric mean WPF found was 39.7. Analytical detection limits, sample contamination, and pulmonary elimination from previous exposures or from skin absorption were identified as important considerations that can bias the WPFs measured. There were significant differences in the mean concentrations found inside the respirator when analyzed by time period. An increase in the concentration found inside the facepiece cavity and a decrease in the WPF over time was found for people with three or four measurements. This indicates either a change in performance of the respirator over time or a bias from low-level exposures during the day or skin absorption.

Air Pollutants, Occupational↗