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Biomedical subjects

J McDonald

Publications and source records attributed to J McDonald.

At least 91 records · Page 5Linked to original sources
PubMed1997

Applications of virtual reality technology in pathology.

TelePath(SM) a telerobotic system utilizing virtual microscope concepts based on high quality still digital imaging and aimed at real-time support for surgery by remote diagnosis of frozen sections. Many hospitals and clinics have an application for the remote practice of pathology, particularly in the area of reading frozen sections in support of surgery, commonly called anatomic pathology. The goal is to project the expertise of the pathologist into the remote setting by giving the pathologist access to the microscope slides with an image quality and human interface comparable to what the pathologist would experience at a real rather than a virtual microscope. A working prototype of a virtual microscope has been defined and constructed which has the needed performance in both the image quality and human interface areas for a pathologist to work remotely. This is accomplished through the use of telerobotics and an image quality which provides the virtual microscope the same diagnostic capabilities as a real microscope. The examination of frozen sections is performed a two-dimensional world. The remote pathologist is in a virtual world with the same capabilities as a "real" microscope, but response times may be slower depending on the specific computing and telecommunication environments. The TelePath system has capabilities far beyond a normal biological microscope, such as the ability to create a low power image of the entire sample using multiple images digitally matched together; the ability to digitally retrace a viewing trajectory; and the ability to archive images using CD ROM and other mass storage devices.

Alabama↗
PubMed1997

Rhinophyma: treatment with CO2 laser.

Rhinophyma is an acne rosacea which primarily affects the midface of elderly men, and causes disfigurement as well as obstruction. There are numerous ways of treating this condition and, in our institution, a CO2 laser is the treatment of choice.

Adult↗
PubMed1997

Nutrition labelling of sugar-containing foods in 1996 compared with 1989.

OBJECTIVE: To record the prevalence of nutrition labelling of foodstuffs with respect to sugar content in selected supermarkets in the UK in 1996 and to compare the prevalence with results reported for 1989. RESEARCH DESIGN: Examination of the labelling of foodstuffs to see whether the labelling of the nutrition content conformed to Government guidelines. Foodstuffs were grouped into 12 types of sugar-containing foods. RESEARCH SETTING: Three large food supermarkets in Newcastle upon Tyne. MAIN OUTCOME MEASURES: Conformity with government guidelines on nutrition labelling of foodstuffs. RESULTS: Most labelling conformed to guidelines. Prevalence had increased considerably between 1989 and 1996. Foods with high sugars content, particularly confectionery, were the least likely to be labelled for sugars content. CONCLUSIONS: Although substantial progress in nutrition labelling for sugars content has occurred, voluntary compliance appears to allow inadequate labelling of high sugar foods.

Beverages↗
PubMed1997

Epidemiology of Echinococcus granulosus infection in the central Peruvian Andes.

The prevalence of human, canine, and ovine echinococcosis was determined in an endemic area of the Peruvian Andes where control programmes have not been operational since 1980. Prevalence of infection in humans was determined using portable ultrasound, chest X-rays, and an enzyme-linked immunoelectrotransfer blot (EITB) assay. Canine and ovine echinococcal prevalence was determined by microscopic stool examinations following arecoline purging for tapeworm detection and by examination of the viscera from slaughtered livestock animals, respectively. The prevalence among 407 humans surveyed was 9.1%. The frequency of disease in the liver, lung, and in both organs was 3.4%, 2.0%, and 0.2%, respectively. Portable ultrasound or portable chest X-ray has shown that, compared to adults, children under 11 years had significantly higher seropositive rates without evidence of hydatid disease (P < 0.05). Among the 104 dogs inspected for echinococcus after arecoline purging, 33 (32%) were positive for adult tapeworms. Among the 117 sheep slaughtered at the local abattoir, 102 (87%) had hydatid cysts. The prevalence of human hydatidosis in this endemic area of Peru is one of the highest in the world and nearly five times higher than previously reported in 1980. An increase in echinococcosis prevalence may result after premature cessation of control programmes.

Adolescent↗
PubMed1996

Influence of benzylisothiocyanate and 13-cis-retinoic acid on micronucleus formation induced by benzo[a]pyrene.

The purpose of this study was to investigate the influence of benzylisothiocyanate (BIT) and 13-cis-retinoic acid (RA) upon the genotoxic potential of benzo[a]pyrene (BaP) to induce micronucleus formation in the bone marrow of mice. Eighty-two male mice were divided into 10 groups. One group served as a negative control (olive oil intubation). Four groups received an oral intubation of various concentrations of BIT (15 to 120 mg/kg) and i.p. injections of BaP (185 mg/kg). Another four groups were treated identically, but received RA (20 to 150 mg/kg) in place of BIT. Finally, one group received only i.p. injection of BaP (185 mg/kg). The results showed that both BIT and RA significantly reduced the frequency of micronucleus formation in the bone marrow of the BaP treated animals. BIT was found to be effective at all the tested concentrations. RA was effective only at three of the four tested concentrations (40, 75 and 150 mg/kg). These findings indicate that both BIT and RA may reduce the genotoxic effects of benzo[a]pyrene in the mice under the test conditions utilized.

Animals↗
PubMed1996

Study of interobserver reliability in clinical assessment of RSV lower respiratory illness: a Pediatric Investigators Collaborative Network for Infections in Canada (PICNIC) study.

Randomized trials of ribavirin therapy have used clinical scores to assess illness severity. Little information on agreement for these findings between observers has been published. We decided to determine interobserver agreement for (1) a history for apnea or respiratory failure; (2) assessment of cyanosis, respiratory rate, retractions, and oximetry; and (3) determination of reason for hospitalization (requirement for medications, supportive care, underlying illness, poor home environment). At eight centers 137 RSV-infected patients were assessed by two observers blinded to the assessments by others with no interventions made between assessments. Observations were categorized, and agreement was summarized as percentage of observed agreement, Pearson correlation, or as a kappa statistic. Observed agreement for a history of either apnea or a respiratory arrest was at least 90% at all centers, with seven of the eight centers in total agreement. At all centers except one, the agreement on the reason why the patient remained in hospital was at least 80%. The observed agreement for assessing cyanosis was at least 94% at all eight centers. The correlation coefficient for respiratory rate varied from 0.42 to 0.97 across centers. The kappa values for agreement beyond chance for retractions varied from 0.05 to 1.00. The kappa values for oxygen saturation measures varied from 0.31 to 0.70. Although not statistically significant, there appeared to be more variation as the time between assessments increased. In conclusion, agreement for historical findings and assessment of cyanosis was high. However, there was wide variation in agreement in the other assessments. Training to ensure consistent and reproducible assessment by different examiners will be necessary if these findings are to be used as outcome variables in clinical trials.

Antiviral Agents↗
PubMed1996

Evolution of promoter sequences: elements of a canonical promoter for prespore genes of Dictyostelium.

An attempt is made to define a minimal prespore promoter which contains all elements essential for correct regulation of expression of a prespore gene. The prespore genes of Dictyostelium are coregulated during development. Most begin transcription at the same early stage, and activity of all is restricted to prespore tissue during the later slug stage. Sequences 5' to the coding sequences of eight prespore genes were searched for all elements proposed to control transcription and for new elements. The meaningfulness of occurrences of elements and pairs of elements in prespore promoters was evaluated by comparison with frequencies of occurrences in promoters of other, nonprespore genes. These comparisons resulted in definition of a canonical prespore promoter, a stretch of about 200 nucleotides containing at least one of each of three elements. Certain limitations were found on the spacing of elements. Orientation of elements with respect to each other appeared unrestricted. All elements often occurred in multiple copies. This structure suggests that individual copies of each element are not conserved during evolution, but instead continually appear and disappear.

Animals↗
PubMed1996

A hypothesis-assessment model of categorical argument strength.

According to the proposed hypothesis-assessment model, the strength of inductive categorical arguments, such as {All Robins Have Substance X therefore All Birds Have Substance X}, is determined by the same factors that affect hypothesis plausibility in the everyday social milieu. The premises of such arguments are viewed as evidence and the conclusion is viewed as a hypothesis. Specifically, the proposed model predicts that the perceived strength of general-conclusion categorical arguments will be a function of (a) the number of premises that instantiate the conclusion; (b) the scope of the conclusion; and (c) the number of accessed alternatives to the conclusion. In Experiment 1, one group rated the strength of individual arguments and another constructed superordinate hypotheses in response to the premise information alone. Most of the variance in perceived argument strength was accounted for by the proposed predictors, R = .94. Experiment 2 employed a new set of arguments and included an additional forced-choice condition in which subjects had to choose the stronger of two arguments. Again, the correlation between predictors and argument strength was high, R = .91, and, all significant forced-choice preferences except one were correctly predicted by the model. The one unpredicted preference suggests the need to include conclusion accessibility as a fourth factor. Also, on a subset of the forced-choice pairs in which no significant preference was observed, two distinct patterns of responding were detected-one predicted and the other unanticipated. Some strengths and limitations of the proposed hypothesis-assessment model are discussed in light of these results.

Adult↗
PubMed1996

Pediatric Investigators Collaborative Network on Infections in Canada (PICNIC) study of admission and management variation in patients hospitalized with respiratory syncytial viral lower respiratory tract infection.

OBJECTIVE: To describe differences in patients hospitalized with respiratory syncytial virus (RSV) lower respiratory tract infection (LRI) at nine Canadian tertiary care hospitals. In addition, this study describes the variation in use of drug and other interventions. METHODS: Data on patients hospitalized with RSV LRI and their outcomes were prospectively collected. Demographic data were obtained on enrollment by center study nurses. Data recorded daily included clinical assessment, oxygen saturation determination, and interventions (bronchodilators, steroids, ribavirin, antibiotics, intensive care, and mechanical ventilation) received during the day. Patients were divided into those with underlying diseases including congenital heart disease, chronic lung disease, immunodeficiency, or multiple congenital anomalies and those who were previously healthy. Mean RSV-associated length of stay and the proportion of patients receiving each intervention in each group were determined by hospital. RESULTS: A total of 1516 patients were enrolled at nine hospitals during January 1 to June 30, 1993, and January 1 to April 30, 1994. Significant differences were observed among hospitals in the proportion of patients with underlying disease, postnatal age less than 6 weeks, hypoxia, and pulmonary infiltrate on chest radiograph. The mean length of stay varied among hospitals from 8.6 to 11.8 days and 4.6 to 6.7 days in compromised and previously healthy patients, respectively. Except for receipt of bronchodilators, compromised patients were significantly more likely to receive interventions than previously healthy patients. There was variation among hospitals in receipt of most interventions in compromised and previously healthy patients. This variation was statistically significant for previously healthy patients but not statistically significant in those with underlying disease, because the numbers of patients in the latter group were much smaller. The magnitude of the variation for each intervention, however, was not different between those with underlying disease compared with previously healthy patients. CONCLUSION: Differences exist among tertiary pediatric hospitals in the nature of the patients admitted with RSV LRI. Variation occurred in the use of five interventions among the hospitals, regardless of whether the patient had underlying illness or was previously healthy. Given their current widespread use, high cost, and potential side effects, randomized clinical trials are needed to determine the efficacy of different drug treatments used to treat infants hospitalized with RSV.

Adrenal Cortex Hormones↗
PubMed1996

High prevalence of sexually transmitted diseases in women with urinary infections.

OBJECTIVE: To determine the prevalence and factors associated with unrecognized sexually transmitted diseases (STDs) in women who had pelvic examinations and were subsequently released from the ED with a sole diagnosis of urinary tract infection (UTI). METHODS: A 3-month retrospective chart review was performed in an urban teaching hospital ED (> 70,000 visits/year). Women aged 12-45 years who had pelvic examinations and were released from the ED with a sole diagnosis of UTI were included. Patient complaints, physical findings, and laboratory results were reviewed. Laboratory evaluations included the complete blood count, urinalysis, urine pregnancy test, and cervical cultures for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas. RESULTS: Of the 94 women who met study criteria, 53% had proven STDs (19% N. gonorrhoeae, 22% C. trachomatis, 33% Trichomonas). There was no difference between the patients with positive and negative tests for STDs with regard to complaints, physical findings, and laboratory results (all p > 0.05). CONCLUSIONS: Women undergoing pelvic examinations who are subsequently released from this urban ED with the diagnosis of UTI have a high (> 50%) prevalence of occult STDs. No complaint, physical finding, or laboratory result reviewed was associated with the risk of an STD. Consideration should be given to empirical antibiotic therapy in similar urban populations.

Adolescent↗
PubMed1996

Rates of tetanus protection and transplacental tetanus antibody transfer in pregnant women from different socioeconomic groups in Peru.

In developing countries, neonatal tetanus causes significant mortality. Using a new competitive enzyme-linked immunosorbent assay to measure anti-tetanus toxin antibody levels, we compared rates of protection, total antibody levels, and maternal-to-fetal antibody ratios between different socioeconomic groups in Peru. Upper-middle-class women 25 years and older had significantly lower rates of protection and mean anti-tetanus toxin antibody levels than did lower-class women of the same age. Nevertheless, the former had higher fetal-to-maternal antibody ratios, independent of maternal age, total antibody levels, or parity. We conclude that future vaccination programs in Latin America must target upper-middle-class as well as lower-class women.

Adolescent↗
PubMed1996

Concurrent utilization review and inappropriate hospital stay: evaluation of a program.

Using a crossover design, we tested the hypothesis that concurrent utilization review by a utilization officer would reduce length of stay and inappropriate bed days in a tertiary care hospital. The intervention groups included 396 consecutive patients admitted to specified services during two 1-month study periods and followed for at least 1 month or until discharge. Controls were 410 patients admitted to the same services during a preceding or subsequent month, separated by a 1-month washout period. Intervention cases had daily review of their care plan and medical condition by the utilization officer to identify existing or likely inappropriate hospital stay. The officer used interdisciplinary and interdepartmental consultation in attempting to resolve identified problems. A separate research nurse identified the controls and gathered data on the medical condition and care plan for a random 50% sample of both intervention and control cases. These data were used by a multidisciplinary panel to count and classify the reasons for inappropriate hospital days. Overall, there were no significant differences between the corresponding intervention and control groups for length of stay or proportion of inappropriate days. There was evidence of a time-related reduction in both length of stay and inappropriate days only in the subgroup of patients with a length of stay of < 15 d. As further evidence of this period effect unrelated to the intervention, length of stay had been declining for 1 of the groups of services before this study began. We concluded that concurrent utilization review, as practiced in this study, was ineffective in the short term. However, utilization review and modification of hospital processes can reduce inefficiency, as evidenced by the time-related reduction in inefficiency illustrated in our study.

Admitting Department, Hospital↗