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Biomedical subjects

S Shannon

Publications and source records attributed to S Shannon.

At least 19 recordsLinked to original sources
PubMed2000

Fine lattice lines on the corneal surface after laser in situ keratomileusis (LASIK).

PURPOSE: To present an example of a pattern of lines resembling fine lattice on the corneal surface subsequent to laser in situ keratomileusis (LASIK). This subtle phenomenon may be relatively common and may affect visual outcome. METHOD: Case report. RESULTS: A 41-year-old year old man with high myopia and best-corrected visual acuity of 20/20 +2 in each eye underwent laser in situ keratomileusis (LASIK). No operative or postoperative complications occurred. No striae were evident on slit-lamp examination with direct illumination and retroillumination at the time of surgery or in the postoperative period. Postoperative uncorrected visual acuity was 20/25 with a best-corrected spectacle correction of 20/25 in both eyes. Fine lines in a lattice pattern were seen only with fluorescein dye in the precorneal tear film as areas of "negative stain" within the LASIK flap. With tear film supplementation, the lines were less evident and visual acuity improved. One year postoperatively, his uncorrected visual acuity was 20/25 in both eyes. The best-corrected spectacle visual acuity was RE: 20/20 -2, LE: 20/25. The fine lines were still present within the flap. A soft contact lens improved visual acuity to 20/20 in both eyes. Although all four puncta were occluded, he had no epiphora. CONCLUSION: Fine lines in a lattice pattern that may represent folds in the epithelium or Bowman layer may be present within the flap after LASIK and may adversely affect visual acuity. They may be visible as areas of negative stain with fluorescein dye in the precorneal tear film in the absence of any striae visible in the flap. These superficial lines have been seen more in patients with high degrees of correction and in patients with dry eye. If visual acuity is affected, it may be improved with punctal occlusion, tear supplements, or a contact lens.

Adult↗
PubMed2000

Predicting electrodiagnostic outcome in patients with upper limb symptoms: are the history and physical examination helpful?

OBJECTIVE: To determine the effectiveness of medical history and physical examination in predicting electrodiagnostic outcome in patients with suspected cervical radiculopathy. METHODS: Data on 183 subjects prospectively collected at five different electrodiagnostic laboratories were analyzed (96 cervical radiculopathies, 45 normal studies, and 42 abnormal electrodiagnostic findings other than radiculopathy). The sensitivity, specificity, positive predictive value, negative predictive value, and odds ratios were determined for symptoms and neurologic signs. RESULTS: Symptoms of numbness, weakness, and tingling were associated with twice the probability of having abnormal electrodiagnostic study results in general, yet were not helpful in identifying a cervical radiculopathy. All single and combined physical examination components had poor sensitivities, with the exception of weakness, but much higher specificities. Patients with either weakness or reduced reflexes on physical examination were up to five times more likely to have abnormal electrodiagnostic findings. In subjects with any abnormal neurologic sign, the sensitivity improved to 84%, the positive predictive value was 79%, but the specificity was low (44%). Of those subjects with normal physical examination results, almost one half had an abnormal electrodiagnostic study result (negative predictive value 52%). CONCLUSIONS: In a population of patients with suspected cervical radiculopathy, medical history and physical examination are helpful yet not sufficient to predict the electrodiagnostic outcome.

Adolescent↗
PubMed1999

Cervical radiculopathies: relationship between symptom duration and spontaneous EMG activity.

The purpose of this multicenter study was to prospectively examine whether denervation in paraspinal muscles (PSM) and in other major proximal and distal muscles is related to symptom duration in cervical radiculopathies (CRs). Information was collected on 93 electrodiagnostically confirmed CRs using standardized history, physical examination, and electromyographic (EMG) screens. Multivariate, maximum-likelihood estimates showed no evidence of correlation between PSM spontaneous activity and symptom duration. Symptom duration was also nonsignificant in eight of the remaining nine upper limb muscles analyzed. We conclude that the probability of spontaneous activity is not related to symptom duration. Clinicians, therefore, should refrain from interpreting electrodiagnostic findings based upon duration of symptoms.

Adolescent↗
PubMed1999

A controlled evaluation of a national continuing medical education programme designed to improve family physicians' implementation of diabetes-specific clinical practice guidelines.

AIMS: New approaches to continuing medical education will facilitate the implementation of clinical practice guidelines. This study assessed the short and long-term impact of a 7-h, small group workshop on family physicians' attitude, knowledge and self-reported practice patterns regarding diabetes mellitus. METHODS: One hundred and seventy-seven of 1807 family physicians who participated in this nationwide workshop, and 113 non-participant controls completed two validated questionnaires. Participants completed one questionnaire before the workshop and a second equivalent questionnaire 1 month later. Non-participant controls also completed the two questionnaires 1 month apart. Between 8 and 24 months later, these individuals were mailed the same questionnaire they completed on the first occasion; 143 participants and 50 controls returned this third questionnaire. RESULTS: Participants were more likely to be female (P = 0.03), not certified in family practice (P = 0.02), in a smaller centre (P = 0.0005), recent medical graduates (P = 0.001) and seeing fewer patients per month (P = 0.01) than controls. Compared to controls, participants had improved their attitude (P<0.0001), knowledge (P = 0.04) and self-reported practice patterns (P<0.002) regarding diabetes after 1 month but not after 1 year. CONCLUSIONS: An interactive, small group, diabetes continuing education programme effectively disseminates practice guidelines to family physicians. The impact of such a programme declines after 1 year.

Canada↗
PubMed1998

Predictive validity of the emergency physician and global job satisfaction instruments.

OBJECTIVE: To evaluate the predictive validity of the Emergency Physician Job Satisfaction (EPJS) and Global Job Satisfaction (GJS) instruments. METHODS: Prospective mail survey of 223 Canadian emergency physicians (EPs) using a 42-item questionnaire, including 14 items evaluating their reasons for leaving emergency medicine (EM). Original (1990) EPJS and GJS scores were analyzed using 1-way ANOVA and Scheffe's test comparing the physicians who left EM with those still in their original jobs, and those who had left their original jobs but who stayed in EM. Mean scores on the 14 "reason for leaving" items were compared with scores from an earlier sample of U.S. physicians using a t-test for independent means. Criteria for statistical significance were set at alpha = 0.05 for all analyses. RESULTS: The response rate for the primary study questions was 99.1%. Of the respondents, 29.4% had left their original jobs, and 10.4% had left EM altogether. The GJS scores for the physicians who left EM were significantly different from those for the physicians who stayed (p = 0.004). The EPJS scores for the physicians who left EM were not significantly different from those for the physicians who stayed (p = 0.56). There was no significant difference in scores between the Canadian and U.S. physicians' reasons for leaving EM (all p-values > 0.05). Shiftwork scored the highest as a reason to leave EM. CONCLUSIONS: A low GJS score is associated with physicians' leaving EM, but not with changing jobs. The EPJS instrument was not associated with either outcome. Canadian and U.S. EPs place similar levels of importance on potential reasons for leaving EM.

Analysis of Variance↗
PubMed1997

Interrater reliability in myofascial trigger point examination.

The myofascial trigger point (MTrP) is the hallmark physical finding of the myofascial pain syndrome (MPS). The MTrP itself is characterized by distinctive physical features that include a tender point in a taut band of muscle, a local twitch response (LTR) to mechanical stimulation, a pain referral pattern characteristic of trigger points of specific areas in each muscle, and the reproduction of the patient's usual pain. No prior study has demonstrated that these physical features are reproducible among different examiners, thereby establishing the reliability of the physical examination in the diagnosis of the MPS. This paper reports an initial attempt to establish the interrater reliability of the trigger point examination that failed, and a second study by the same examiners that included a training period and that successfully established interrater reliability in the diagnosis of the MTrP. The study also showed that the interrater reliability of different features varies, the LTR being the most difficult, and that the interrater reliability of the identification of MTrP features among different muscles also varies.

Adult↗
PubMed1996

The impact of the Medicare Influenza Demonstration Project on influenza vaccination in a county in Massachusetts, 1988-1992.

Influenza and related pneumonia continue to cause significant amounts of morbidity and mortality despite the availability of effective vaccines. Two comparable counties in Massachusetts served as project areas of a national trial to see if reimbursement for immunizing Medicare-B eligible recipients against influenza would increase the use of the vaccine and reduce the costs attributed to related morbidity. Providers of health and social services to elders were recruited to participate in one county. A variety of professional and public education campaigns and media were used to promote influenza immunizations. Laboratory-based surveillance was instituted in both counties to assess the extent of circulating virus in each. Vaccine was made available to medical providers in both counties. While the amount of vaccine used in the comparison county increased by 6% from pre-project time (16,000 to 17,000 doses administered), vaccine use increased 219% in the intervention county (21,250 to 46,494 doses administered). In a post-project survey of participating physicians, 88% of 238 respondents reported administering less than 100 doses of influenza vaccine per year prior to the project. By the end of the project, only 32% administered less than 100 in the previous year. This project demonstrated the need for educating both the provider and the public in order to successfully promote immunizations. It was not clear, however, if reimbursement was a more important factor for promoting influenza immunizations than was universal distribution of free vaccine.

Aged↗
PubMed1994

Development of the emergency physician job satisfaction measurement instrument.

The objective of this study was to develop a valid and reliable instrument to measure the job satisfaction of physicians practicing emergency medicine. A prospective survey involving four separate stages (an item evaluation and reduction stage, a factor analysis stage, a construct validity stage, and a reliability stage) was distributed in Canada to full-time emergency physicians. Three separate survey instruments were administered (an initial draft instrument with 228 items, a pilot instrument with 142 items, and the final instrument with 79 items). Construct validity of the final instrument was tested by evaluating the correlation between physician scores on the instrument, and scores on two instruments measuring the same construct, and three measuring different but related constructs. A draft instrument with 228 items and six hypothetical domains was tested on 61 physicians. Evaluation for frequency endorsement, redundancy, and homogeneity reduced the item pool to 157. The remaining 157 items were used as a pilot instrument and tested on 223 physicians. Factor analysis eliminated 66 items from the pilot instrument, creating a final instrument with 79 items, 11 factors, and six domains. Cronbach's coefficient alpha for the final instrument domains is 0.81, and all domain-total correlations are greater than 0.4. All correlations between the final instrument and the construct validity instruments were statistically significant (P < .001), but not so high that they appeared to be measuring the same thing. Correlations between instruments measuring the same construct were higher than those measuring related but different constructs. Correlations between the final instrument and the CES-D scale, emotional exhaustion, and depersonalization subscales of the Maslach Burnout Inventory were negative. A test-retest reliability study on 42 physicians showed Pearson's correlation coefficients for individual domains were all greater than 0.7 and greater than 0.8 for the final instrument. This study has produced a valid and reliable instrument for measuring emergency physician job satisfaction, which is both internally consistent and stable.

Canada↗
PubMed1994

Family medicine residency programs. Evaluating the need for different third-year programs.

We asked hospital chief executive officers (CEOs) and District Health Council executive directors (DHCs) to compare third-year family medicine residency programs and judge which are more needed in their communities. Care for the elderly and emergency medicine ranked highest among CEOs, while DHCs ranked care for the elderly and mental health highest. Academic family medicine and northern programs ranked lowest for both groups.

Attitude of Health Personnel↗
PubMed1993

Demographic characteristics of full-time emergency physicians in Canada.

The objective of this study was to describe individual and practice characteristics of Canadian emergency physicians, and to determine if these characteristics varied with geographic region, type of certification, or method of reimbursement. The study took place in emergency departments across Canada, and all full-time physicians with certification in emergency medicine, and a random sample of Canadian Association of Emergency Physician members without certification were surveyed with a 23-item questionnaire. Descriptive statistics on individual and practice characteristics were outcome measures. Comparative statistics evaluating demographic characteristics by region, type of certification, and method of reimbursement were used. There were significant differences between responders and nonresponders based on certification (P < .001) and region of residence (P < .005). Most physicians are male (87.3%), married (83.3%), reimbursed on a fee for service basis (61%), work in teaching hospitals (65.8%), and participate in medical education (82.3%). On average physicians are 38 years of age, work of 14 shifts/month, 9 hours/shift, 11 nonclinical emergency related hours/week, and have 5 vacation weeks/year. More physicians with FRCP(EM) certification work in teaching hospitals (P < .00001), do nonclinical emergency related work (P < .0001), participate in medical education (P < .0001), and are involved in research (P < .001). There are significant differences by geographic region in gross annual salary (P < .00001), method of reimbursement (P < .00001), and independent hospital emergency department status (P < .00001). Fee-for-service reimbursement for clinical service provides a higher gross annual income than other methods (P = .028). Emergency medicine is an emerging clinical discipline with a strong academic focus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

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↗
PubMed1990

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↗
PubMed1987

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↗
PubMed1987

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↗
PubMed1986

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↗
PubMed1983

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↗