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Biomedical subjects

S Shannon

Publications and source records attributed to S Shannon.

At least 37 records · Page 2Linked to original sources

Health-risk behaviors of Army aircrew.

Data from the US Army Health Risk Appraisal Program were used to compare health and fitness levels in flight and nonflight personnel. Survey data collected from an aviation brigade, consisting of 428 aircrew and 899 support personnel, were compared with US Army summary statistics. Flight personnel scored better on evaluation of hypertension, stress, weight standards, and seatbelt use. However, the prevalence of smokeless tobacco use, heavy alcohol consumption, and driving after drinking or riding with someone who consumed alcohol was significantly higher in flight personnel. This study suggests that although Army aircrew have better lifestyle habits overall, high-risk behaviors have been identified that warrant further evaluation.

Adult↗

Effect of dietary fiber on symptoms and rectosigmoid motility in patients with irritable bowel syndrome. A controlled, crossover study.

The aims of this study were to determine (a) whether dietary fiber supplements modify symptoms in patients with irritable bowel syndrome, (b) the effect of fiber on rectosigmoid pressures, and (c) the relationship, if any, between rectosigmoid pressure and symptoms. Fourteen patients entered and 9 completed a double-blind, controlled, cross-over study of 7 mo duration. The mean age was 26 yr (range, 18-37). Patients received 4 cookies daily containing 20 mg corn fiber or placebo. Symptoms and compliance were evaluated monthly. Rectosigmoid pressures and dietary intake were evaluated at the outset and completion of each study arm. Symptoms improved during both fiber and placebo treatments. Those symptoms demonstrating significant improvement with time were pain severity, stool frequency, stool consistency (p = 0.001), number of additional gastrointestinal symptoms present (p = 0.02), and total symptom score (p less than 0.001). Rectosigmoid pressures were not significantly altered by fiber or placebo. Fasting pressures at the distal recording site tended to correlate with pain severity (r = 0.6; p = 0.06). It was concluded that (a) corn fiber and placebo were both effective in alleviating symptoms, (b) there was a correlation between symptom severity and fasting rectosigmoid pressure, and (c) there was a trend toward reduction in fasting and postprandial rectosigmoid pressures after fiber therapy.

Adult↗

Measurement of upper esophageal sphincter pressure. Effect of acute emotional stress.

Recent studies suggest that resting upper esophageal sphincter pressure is more labile than previously thought, being augmented during rapid manometric pull-through and markedly decreased during sleep and anesthesia. The effect of acute emotional stress on resting upper esophageal sphincter pressure was evaluated in 13 normal subjects with a manometric sleeve assembly. Manometric sideholes were positioned in the pharynx and cervical and thoracic esophagus while the sleeve sensor straddled the upper esophageal sphincter. Subjects were stressed intermittently by 14-min periods of a dichotic listening task. As incentive, a financial reward was offered and made commensurate with performance. Alterations of heart rate, blood pressure, and skin conductance confirmed the effectiveness of the stressor. The overall mean upper esophageal sphincter pressure during control periods was 46.5 mmHg (SEM = 4.7). During stress there was a significant mean increase (11.8 +/- 2.9 mmHg; p = 0.002) in upper esophageal sphincter pressure from control levels, and the pressure increase during the first 2-min epoch of stress was 20.8 +/- 3.9 mmHg (p = 0.0003). Emotional stress causes significant elevation of upper esophageal pressure in normal subjects. This effect is likely to influence resting sphincter pressure measurements, particularly if measurement conditions are stressful to the subject.

Acute Disease↗

The action of trimebutine maleate on gastrointestinal motility is mediated by opiate receptors in human subjects.

The effects of trimebutine on interdigestive motor activity of the small intestine and the colon were studied in healthy volunteers. Trimebutine induced in all subjects phase III-like motor complexes, which were similar to spontaneously occurring phase III complexes of the interdigestive cycle in antrum and duodenum. Trimebutine-induced complexes were suppressed by naloxone. Trimebutine and/or naloxone had no consistent effect on interdigestive contractile activity in the colon.

Adult↗

Comparison of methodologies for the measurement of antroduodenal motor activity in the dog.

We have compared the abilities of intraluminal strain gauges and manometry to record motor activity from the antrum and duodenum of the anesthetized dog. Responses to intraarterial carbachol, vagal stimulation, and field stimulation recorded by these devices were compared to those registered by strain gauges sewn onto the overlying serosa. In the antrum, the perfused tube (PT) recorded 98% and 97% of field- and vagal-stimulated phasic contractions, respectively, compared with 83% and 90% (p less than 0.005) registered by the intraluminal tube-mounted strain gauges (TSGs). In contrast, in the duodenum there was no difference between the accuracy of these devices in recording phasic activity induced by field stimulation (PT 90% and TSG 87%). Similarly, there was no difference between the abilities of these devices to record tonic contraction induced by carbachol in the antrum (PT 87% and TSG 90%) or duodenum (PT 82% and TSG 87%). However, TSGs misrepresented the configuration of phasic or tonic contractions, producing bifid, negative, or biphasic contractions substantially more frequently than did PT (p less than 0.005). These results illustrate that the accuracy of these two commonly used techniques may be influenced by anatomic factors as well as by the type of contraction recorded.

Animals↗

Energy balance and nitrogen balance in growing low birthweight infants fed human milk or formula.

Energy and nitrogen balances were measured in growing low birthweight infants fed either mother's expressed breast milk or a 20 kcal per ounce formula to determine whether or not there were differences between the two dietary groups in (1) the partition of energy among excretion, expenditure, and storage and (2) the relation of energy storage and nitrogen retention to weight gain. There were no significant differences between the human milk fed infants and formula fed infants in gross energy intake, metabolizable energy intake, nitrogen intake, or nitrogen retention. Energy expenditure was significantly lower in the human milk fed infants than in formula fed infants (221 kJ/(kg. day) and 244 kJ/(kg. day), respectively). There was no difference in mean energy storage between the two groups. Although weight gains were similar in both dietary groups, the ratio of energy storage to weight gain was significantly greater in infants fed with human milk (15.3 kJ/g, S.D. 2.0) than in infants fed formula (13.2 kJ/g S.D. 1.8). There was no significant difference between the two groups in the ratio of nitrogen stored to weight gain.

Body Weight↗

Sequestration and turnover of guinea-pig milk proteins and chicken ovalbumin in Xenopus oocytes.

The stability and distribution of proteins within the living cell can be studied using Xenopus laevis oocytes. Microinjection of messenger RNAs and secretory proteins, followed by cell fractionation, shows that transfer of ovalbumin and milk proteins across intracellular membranes of the oocyte only occurs during their synthesis. Thus milk protein primary translation products, made in the wheat germ cell-free system, when injected into oocytes remain in the cytosol and are not recovered within membrane vesicles. Such miscompartmentalized primary milk proteins are rapidly degraded (t 1/2 0.6 +/- 0.1 h). In contrast, processed milk proteins, extracted from oocytes injected with mammary gland RNA, are relatively stable when introduced into the cytosolic compartment (t 1/2 alpha-lactalbumin 20 +/- 8 h, casein A 6 h, casein B 4 h, casein C 8.3 h). The primary ovalbumin product is also stable (t 1/2 22 +/- 9 h). Indirect evidence that rapid degradation of miscompartmentalized milk protein primary translation products may occur in vivo was obtained by the injection of massive amounts of ovalbumin and milk protein mRNA. Under these conditions there is no accumulation of primary milk protein translation products, but a polypeptide resembling the unglycosylated ovalbium wheat germ primary product can be detected in the cytosol. Only the glyclosylated forms of ovalbumin are found in the oocyte membrane vesicle fraction. We discuss the roles played by the presence of detachable signal sequences and the absence of secondary modifications in determining the rate of degradation of primary translation products within the cytosol.

Animals↗

72-hour discharge after cesarean delivery: results in a selected Medicaid population.

The purpose of this study was to determine the safety and cost savings of discharging low income patients at 72 hours following cesarean delivery. Predetermined criteria were used to allow discharge. Selection criteria were no medical problems, an afebrile postoperative course, documented bowel function, to have tolerated at least one regular meal, and to have reached 72 hours postdelivery by 6 o'clock PM at discharge. Each patient returned to clinic 2-3 days postdischarge for staple removal. Physicians also discharged some low income patients home at 72 hours even though strict eligibility criteria were not met. Maternal outcome and financial data were compared between patients discharged after meeting eligibility criteria versus those who did not. Of 1,299 cesareans performed from July 1, 1993-July 31, 1995, 906 (70%) were performed in low income patients and 399 (44%) of these women were discharged at 72 hours. Twenty-seven women were lost to follow-up and 286 (77%; Group A) met the eligibility criteria for 72-hour discharge. Eighty-six women (23%; Group B) who did not meet criteria were also discharged at 72 hours. When maternal outcome data from the two groups were compared, Group B patients (did not meet criteria) were more likely to have been readmitted at < or = 30 days (7 of 86; 8% vs. 8 of 286; 3%; P = 0.05) and had longer hospital stays (27 days vs. 22 days) than Group A patients (met criteria). Net cost savings in 2 years was $448 per discharge for Group A, but only $333 per discharge for Group B. In our selective 72-hour discharge program, failure to abide by predetermined guidelines established to select only low risk, afebrile patients for 72-hour discharge resulted in more hospital readmissions, and longer stays and thus was not as cost effective.

Adult↗

The sinister significance of dysphagia.

BACKGROUND: The majority of patients presenting with oesophageal cancer have symptoms for more than three months and advanced disease at presentation. Most appear unaware of the significance of dysphagia as a symptom. Cancer awareness programmes focus on symptoms such as lumps and bleeding. AIM: To sample the level of public awareness of the potentially sinister significance of the symptom of dysphagia. METHODS: A community survey was conducted using a questionnaire to evaluate the subjects' impression of the significance of dysphagia, and compare it with their perception of the significance of breast lump. Patients were stratified to male and female, under and over 45 years. RESULTS: There were 164 subjects interviewed. Seventy-five per cent stated that they would visit their doctor within one week of developing dysphagia compared with 87 per cent questioned about a breast lump (96 per cent females, 80 per cent males). Only 17 per cent felt that cancer was a probable explanation for dysphagia compared with 80 per cent who would consider cancer a likely cause of breast lump. CONCLUSION: There is evident need of an awareness programme of the potential significance of dysphagia if prognosis for oesophageal cancer is to be improved.

Adult↗

Burnout, depression, life and job satisfaction among Canadian emergency physicians.

Our goal was to determine the level of burnout, depression, life and job satisfaction of Canadian emergency physicians. Six instruments were administered: the emotional exhaustion, depersonalization, and personal accomplishment intensity subscales of the Maslach Burnout Inventory (MBI); the Centre for Epidemiologic Research Self-Report Depression Scale (CES-D); the Satisfaction With Life Scale (SWLS); and the Emergency Physician Job Satisfaction Measurement Instrument (EPJS). Forty-six percent of the sample fell within the medium to high level of emotional exhaustion, 93% within the medium to high range for depersonalization, and 79% within the medium to low range for personal accomplishment. Sixty-one percent were satisfied with their lives, and 75.5% were satisfied with their jobs. Multiple regression analysis showed that increased age, being a department head, and increased weeks of holiday per year were positive contributors to EPJS scores (P < 0.05). Involvement in medical education, increased clinical hours worked per year, and region of residence-Quebec were negative contributors to EPJS scores (P < 0.05). Involvement in medical education is a significant factor among physicians experiencing depressive symptomatology. Time away from clinical practice is important to job satisfaction and emotional well-being.

Adult↗

Effect of history and exam in predicting electrodiagnostic outcome among patients with suspected lumbosacral radiculopathy.

OBJECTIVE: To determine the extent to which the history and physical examination predict the outcome of the electrodiagnostic (EDX) evaluation in patients with suspected lumbosacral radiculopathy. DESIGN: Data for 170 subjects referred for low-back and lower limb symptoms were prospectively collected at five EDX laboratories. The sensitivity, specificity, positive and negative predictive values, and odds ratios were determined for symptoms and neurologic signs. RESULTS: Symptoms were not significantly associated with an EDX study or a lumbosacral radiculopathy. The physical examination was better at predicting that an EDX study would be abnormal in general than it was at predicting a lumbosacral radiculopathy in particular. Of those subjects with normal physical examinations, 15%-18% still had abnormal EDX findings. CONCLUSIONS: In a population of patients referred for an EDX study, the history and physical examination alone cannot reliably predict electrodiagnostic outcome.

Adolescent↗

Symptom duration and spontaneous activity in lumbosacral radiculopathy.

OBJECTIVES: A long-held notion in the electrodiagnostic literature is that paraspinal muscles tend to show spontaneous activity (fibrillations and positive sharp waves) on needle electromyography, early on in a lumbosacral radiculopathy, and that more distal muscles become abnormal later in the disease process. The purpose of this study was to determine whether paraspinal muscle and other major proximal and distal muscle spontaneous activity is related to a lumbosacral radiculopathy symptom duration. METHODS: A multicenter, prospective study that collected standard information on history, physical examination, and electrodiagnostic findings in patients with electrodiagnostically confirmed lumbosacral radiculopathies was undertaken. RESULTS: Multivariate probit analyses of 96 patients identified with a lumbosacral radiculopathy showed no evidence of correlation between spontaneous activity in the paraspinal muscles and symptom duration. Symptom duration was also nonsignificant in nine of the remaining ten lower limb muscles analyzed. CONCLUSION: These findings emphasize the limitations of using symptom duration when interpreting electrodiagnostic findings in lumbosacral radiculopathy.

Action Potentials↗

Identifying lumbosacral radiculopathies: an optimal electromyographic screen.

OBJECTIVE: The objective of this study was to determine prospectively the optimal electromyographic screening examination of the lower limb that ensures identification of those lumbosacral radiculopathies that can be electrodiagnostically confirmed, yet minimizes the number of muscles studied. DESIGN: A prospective multicenter study was conducted from May 1996 to September 1997. Patients with suspected lumbosacral radiculopathy referred to participating electrodiagnostic laboratories were recruited and examined by needle electromyography using a standard set of muscles. Patients with electrodiagnostically confirmed lumbosacral radiculopathies were selected for analysis. Various muscle screens were tested against this group of patients with radiculopathies to determine the frequency with which each screen identified the patient with radiculopathy. RESULTS: There were 102 patients identified. When paraspinal muscles were one of the screening muscles, four-muscle screens identified 88-97% of the radiculopathies, five-muscle screens identified 94-98%, and six-muscle screens 98-100%. When paraspinal muscles were not part of the screen, identification rates were lower for all screens, and eight distal muscles were necessary to identify about 90% of the radiculopathies. CONCLUSIONS: Six-muscle screens with paraspinal muscles yielded consistently high identification rates. Studying additional muscles produced no improvements in identification.

Adult↗

Folds and striae in laser in situ keratomileusis flaps.

PURPOSE: To classify striae and folds seen after laser in situ keratomileusis. METHODS: The authors' experience and review of the literature form the basis for the proposed classification. RESULTS: Five types of folds and striae are described: loose epithelium, hinge ridge, hinge fold, deep stromal striae, deep epithelial/Bowman's striae. CONCLUSION: Linear striae in laser in situ keratomileusis flaps have a variety of appearances and different postoperative courses that require accurate diagnosis and management.

Epithelium, Corneal↗