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Biomedical subjects

S Smith

Publications and source records attributed to S Smith.

At least 1,153 records · Page 64Linked to original sources
PubMedDate not supplied

Prediction of brain blood flow using pulsed Doppler ultrasonography in newborn lambs.

The purpose of this study was to evaluate the ability of pulsed Doppler ultrasonography to predict brain blood flow by comparing measurements made in basal cerebral arteries using a pulsed Doppler system with measurements of brain blood flow using radioactive microspheres in lambs. We measured the instantaneous maximum velocity during peak systole and end diastole and the mean velocity over the pulse cycle in basal cerebral arteries, calculated Pourcelot's index of resistance and Gosling's pulsatility index, and used regression analysis to compare the pulsed Doppler measurements with brain blood flow measured with radioactive microspheres. Pulsed Doppler measurements of the peak systolic, end diastolic, and mean flow velocity in basal cerebral arteries were directly related to brain blood flow. In contrast, no linear relationship was detected between the resistance or pulsatility indices and brain blood flow measured by microspheres (p greater than 0.14). Prediction of brain blood flow for individual subjects lacks the quantitative precision necessary for use as a clinical tool. However, the direct relationship between brain blood flow and the peak systolic, end diastolic, and mean flow velocities in basal cerebral arteries supports the use of these measurements in clinical research for the qualitative assessment of change in brain blood flow.

Animals↗
PubMedDate not supplied

Patients' views on out-of-hours care in general practice in Dublin.

BACKGROUND: Little is known regarding patients' views and levels of satisfaction with out-of-hours care in Irish general practice despite significant recent changes in service delivery. AIMS: This study aimed to record patients' experience of out-of-hours care on a specific occasion and elicit their satisfaction with out-of-hours care in general. METHODS: Patients requesting out-of-hours care in three south inner city Dublin practices in June and July 2000 were identified and sent an anonymous postal questionnaire. RESULTS: Two hundred and forty patients were identified and 58% responded to the questionnaire. The approximate call rate was 195 calls per 1,000 patients per year. Sixty-one per cent of patients used the co-operative service, 28% received a house call and 3% received telephone advice only; 86% are currently satisfied with out-of-hours care. CONCLUSIONS: The majority of patients are satisfied with the current out-of-hours service. Telephone consultation rates are significantly lower than other countries. These findings need to be considered before the widespread introduction of systems involving increased telephone consultations.

Adolescent↗
PubMedDate not supplied

Cytogenetic and molecular characterization of a congenital mesoblastic nephroma.

A newborn baby boy was diagnosed with the mixed form of congenital mesoblastic nephroma (CMN) representing both classic and cellular histology features in the renal tumor. Additionally, the patient had skin and bone lesions consistent with multifocal involvement of a generalized infantile fibromatosis (IFS). Both skin and bone lesions were distinctly different from CMN and did not represent metastasis. The primary tumor cell line (MCH-MN-1), established from the resected right kidney tumor, had a diploid DNA content. Cytogenetic studies revealed deletion on the long arm of chromosome 3 (q21q24) and duplication on the short arm of chromosome 11 (p15). MCH-MN-1 cells expressed ETV6-NTRK3 gene fusion transcripts, characteristic of cellular and mixed forms of CMNs. The cells had high p21 and low Bax mRNA expression in the reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The high level of proliferative marker (Ki67) mRNA expression correlated well with the pluripotent nature of MCH-MN-1 in tissue culture (cell doubling time = 12.4 h). Our results showed that MCH-MN-1 might be a good model cell line for investigations on mesoblastic nephroma.

Chromosome Deletion↗
PubMedDate not supplied

Lacrimal ductal cysts. Presentation and management.

The authors have reviewed the clinical and histopathologic features of nine cases of lacrimal ductal cysts. Six of these were proven histologically, and three were diagnosed clinically. All presented as masses, three with pain, five with tenderness and two with acute expansion due to hemorrhage in one case and following crying and deep sea diving in the other. Six were treated surgically and three are being followed clinically. The six lesions examined histologically were all ductal cysts with evidence of scarring and inflammation. The differential diagnosis and management are outlined.

Adult↗
PubMedDate not supplied

Correlation of computed tomographic and histopathologic features in malignant transformation of benign mixed tumor of lacrimal gland.

A 65-year-old man had painless progressive proptosis of five years' duration in his left eye. Sudden increase of the proptosis required a lateral canthotomy. A lateral orbitotomy was performed and a large, encapsulated, globoid mass was totally excised. Histopathologic diagnosis was adenoid cystic carcinoma arising in and surrounding a benign mixed tumor of the lacrimal gland. The computerized tomographic features correlated quite accurately with the gross appearance and histopathologic findings observed in the lacrimal gland mass. The authors discuss the clinical and radiographic features that should alert the clinician to the possibility of malignant transformation in a benign mixed tumor of the lacrimal gland.

Aged↗
PubMedDate not supplied

Faculty perceptions of teaching on television: one school's experience.

Videoteleconferencing (or teaching on television) represents a means of growing importance for distant learners to gain greater access to nursing education. Research has identified a number of key issues for nurse educators to consider related to videoteleconferencing: teaching/evaluation strategies, faculty workload, rewards and incentives, and support structures. The authors conducted an evaluation survey using a case study approach aimed at describing the perceptions of a convenience sample of faculty members (n = 17) regarding their recent television experiences. The survey, conducted by means of a mailed questionnaire, examined perceptions centering on sources of support, reception site logistics, rewards teaching strategies, and future directions. Key findings included: overall, respondents perceived television teaching positively; reception site, administrative support, and peer support were important to faculty; additional preparation time was required for television teaching; teaching on television required changes in style and pedagogical strategies; and student-teacher interactions were affected by the medium. Findings have implications for the implementation of videoteleconferencing operations, recruitment of faculty for television teaching, and evaluation of videoteleconferencing operations.

Attitude of Health Personnel↗
PubMedDate not supplied

Determination of body composition in conscious adult female Wistar utilising total body electrical conductivity.

Total body electrical conductivity (TOBEC) is a noninvasive method for estimating fat free mass (FFM) in live animals. In this study, we have evaluated the use of the Em-Scan SA-3000, which is claimed by the manufacturers to perform better than earlier analysers. Previous studies in rats using these earlier versions of the TOBEC analyser have always used anaesthesia to minimise movement artefacts. As repeated anaesthesia also has the potential to induce artefacts by disrupting food intake, for example, we have also attempted to determine if this TOBEC analyser can be used to predict body composition in conscious adult weight-stable female Wistar rats. A simplified cafeteria diet was used to produce large variations in body composition (40-350 g fat/carcass) and a full chemical body composition analysis was performed to generate a TOBEC calibration equation. The TOBEC parameter was more strongly correlated to FFM (r(2)=.785) than it was to body weight (r(2)=.669) or other body composition parameters. Using the TOBEC calibration equation to predict fat mass on these data, there was an excellent correlation with the value obtained by chemical analyses (r(2)=.952, slope=0.958). To determine if the TOBEC calibration equation derived from this calibration study would then be useful for the routine estimation of body composition an additional, validation study was performed. This validation study was performed 6 months later, used an independent group of obese female Wistar rats and was undertaken by different TOBEC operators. This validation study, again, showed a good correlation between the TOBEC- and chemical-derived fat mass (r(2)=.918, slope=1.003) indicating stability of the calibration equation with time and independence from operator. We therefore conclude that it is possible to meaningfully estimate body fat changes in conscious rats using this TOBEC analysis system.

Adipose Tissue↗
PubMedDate not supplied

Personality disorders in problematic medical patients.

To better understand problematic medical patients, the psychiatric diagnoses of 448 patients referred to a behavioral medicine clinic were examined. Forty-two percent met DSM-III-R personality disorder criteria. Analysis of the comorbidity of Axis I and Axis II diagnoses revealed a statistically significant co-occurrence between somatoform and personality disorders (P < 0.0001). Some of the difficulties in making a personality disorder diagnosis are reviewed, as are reasons why knowledge of personality disorder diagnoses is important to medical providers.

Adult↗
PubMedDate not supplied

Assessment of the efficacy and effectiveness of influenza vaccines in healthy children: systematic review.

BACKGROUND: We aimed to assess evidence of efficacy and effectiveness of live attenuated and inactivated influenza vaccines in children up to 16 years of age. METHODS: We searched the Cochrane Library, MEDLINE, EMBASE Biological Abstracts, and Science Citation Index to June, 2004, in any language, and contacted vaccine manufacturers and authors of relevant studies to identify additional data. We included randomised, cohort, and case-control studies comparing efficacy of vaccines against influenza (reduction in laboratory-confirmed cases), effectiveness of vaccines against influenza-like illness (reduction in symptomatic cases), or both, with placebo or no intervention. We analysed the following outcomes: influenza, influenza-like illness, admissions, school absences, complications, and secondary transmission. FINDINGS: We included 14 randomised controlled trials, eight cohort studies, one case-control study, and one randomised controlled trial of intraepidemic use of the vaccines. Live attenuated influenza vaccines had 79% efficacy and 38% effectiveness in children older than 2 years compared with placebo or no immunisation. Inactivated vaccines had lower efficacy (65%) than live attenuated vaccines, and in children aged 2 years or younger they had similar effects to placebo. Effectiveness of inactivated vaccines was about 28% in children older than 2 years. Vaccines were effective in reducing long school absences (relative risk 0.14 [95% CI 0.07-0.27]). Studies assessing the effects of vaccines against secondary cases, lower-respiratory tract disease, acute otitis media, and hospital stay suggested no difference with placebo or standard care, but lacked statistical power. INTERPRETATION: Influenza vaccines (especially two-dose live attenuated vaccines) are efficacious in children older than 2 years. Efficacy and effectiveness of the vaccines differed strikingly. Only two small studies assessed the effects of influenza vaccines on hospital admissions and no studies assessed reductions in mortality, serious complications, and community transmission of influenza. If influenza immunisation in children is to be recommended as public-health policy, large-scale studies assessing such important outcomes and undertaking direct comparisons of vaccines are urgently needed.

Adolescent↗
PubMedDate not supplied

Neisseria gonorrhoeae: vaginal clearance and its correlation with resistance to infection in subcutaneous chambers in orally immunized estradiol-primed mice.

The rate of clearance of Neisseria gonorrhoeae in vaginal specimens harvested from inbred Balb/c and outbred (Institute of Cancer Research [ICR]) white mice, previously primed with saline or beta-estradiol and then challenged with live gonococci, was determined. Survival of gonococci was significantly (P < 0.05) better in estradiol-primed mice from both inbred and outbred lines at 24 h after challenge. Vaginal clearance of gonococci from ICR mice parenterally primed with a gonococcal PI-B synthetic peptide and then orally immunized with gamma irradiated, protein-III deficient gonococcal cells was significantly (P < 0.001) faster than in corresponding nonimmunized, estradiol-primed controls. The more rapid vaginal clearance in the orally immunized mice was correlated with an elevated subcutaneous chamber ID50% (> 100,000 colony forming units) determined for the same groups of mice. Peptide-primed mice orally immunized with irradiated Escherichia coli cells demonstrated a chamber ID50% of < 100 CFU and were significantly (P < 0.01) slower to clear gonococci following vaginal challenge. High levels of specific IgA and IgG antibodies to gonococci were detected by an enzyme-linked immunosorbent assay in vaginal wash specimens from orally immunized mice. However, high antibody titers were not always predictive of an increased resistance to vaginal challenge. These models may be helpful in providing more economical and accessible in vivo methods for screening certain gonococcal vaccine candidates before more expensive testing in chimpanzees or humans.

Administration, Oral↗
PubMedDate not supplied

Transesophageal echocardiographic evaluation of right atrial mass lesions.

Transesophageal echocardiography with color flow Doppler studies was performed on 10 consecutive patients who had right atrial masses identified by transthoracic echocardiography. In one patient with right atrial myxoma, transesophageal study identified the tumor by its attachment to the atrial septum and ruled out the transthoracic finding of possible additional tumor mass in the right ventricle. In two instances the mass in the atria were deemed to be thrombi because of lack of attachment to the atrial septum, atrial fibrillation, and enlarged right atrial chambers. In all patients, the thrombi appeared larger by transesophageal study and was associated in one instance with atrial septal defect. The atrial septal defect was not identified by the transthoracic study and probably accounted for stroke of the patient through paradoxical emboli. In six patients, because of superior quality images rendered by transesophageal imaging, the right atrial mass lesions were deemed to be anatomic variants, which included prominent eustachian valves, remnants of Chiari network, and thickened atrial septum. We concluded that transesophageal echocardiography is superior to transthoracic imaging in elucidating the cause and significance of right atrial mass lesions and that it helps in guiding appropriate therapy.

Adolescent↗
PubMedDate not supplied

Neural substrates of the tilt illusion.

PURPOSE: It has been suggested that direct and indirect tilt illusions and after-effects have different mechanisms, namely that the direct effects arise in VI and are sensitive to differences in spatial and temporal parameters between test and inducing stimuli, whereas indirect effects arise in extrastriate cortex and are insensitive to such parameters. When Wolfe (Vision Research 1984; 24: 1959-64) reported that large direct tilt after-effects occurred with short test flashes, he postulated that either there are distinct mechanisms which process brief and longer duration stimuli or that there are distinct mechanisms that are not primarily concerned with duration but are differentially responsive to temporal parameters amongst several others. RESULTS: In three experiments we demonstrate that large direct tilt illusions can be induced when parameters other than duration are manipulated, including contrast and spatial frequency, and that such large effects can occur when stimulus parameters are chosen to favour preferentially either the transient (magnocellular-like) system or the sustained (parvocellular-like) system. CONCLUSIONS: These results are thus consistent with Wolfe's second hypothesis. None of these stimulus manipulations had any effect on indirect tilt illusions, consistent with previous findings and hypotheses about the different mechanisms of the direct and indirect effects.

Brain↗
PubMedDate not supplied

What to do when the end is near: ethical issues in home health care nursing.

As managed care shortens the length of hospital stays, home settings for the practice of nursing will become increasingly important. In spite of community health nursing's long tradition of family-centered care delivered in the home, many discussions of the nurse/patient relationship in the medical ethics literature assume the hospital setting for the practice of nursing and seem to neglect the impact of family and significant others for the nurse/patient relationship. Through a case-based analysis, this article highlights the special ethical and legal issues encountered in caring for patients who are dying at home. This analysis demonstrates that traditional frameworks for the nurse/patient relationship are inadequate for capturing the richness of the relationship the home health care nurse has with both patient and family. By developing a new framework for the nurse/patient/family relationship that (a) recognizes the patient's decision-making authority and autonomy, (b) allows the exercise of the nurse's moral rights, and (c) recognizes the patient's relationships to significant others, the authors attempt to resolve some challenging legal and ethical questions concerning who should be allowed to decide what to do when the end is near. The discussion details the implications of this framework for nursing assessment in the home care setting.

Advance Directives↗
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Modifiable and nonmodifiable factors associated with osteoporosis in postmenopausal women: results from the Third National Health and Nutrition Examination Survey, 1988-1994.

We wished to study the relationship between modifiable and nonmodifiable factors that were correlated with osteoporosis using a national sample of women aged 50 years and older who have never been on hormone replacement therapy (HRT). We used a cross-sectional study design with a nationally representative sample with a detailed clinical examination and a home interview. Between 1988 and 1994, 1953 postmenopausal women who had never been on HRT, aged 50 years and older, were examined as part of the Third National Health and Nutrition Examination Survey (NHANES III). Mexican Americans and non-Hispanic blacks were oversampled to produce reliable estimates for these groups. Bone density measurements of four proximal femur sites were assessed by using x-ray absorptiometry (DEXA). A DEXA measurement at any single femur site indicated osteoporosis if it was >2.5 standard deviations (SD) below the reference mean of 20--29-year-old women. The study demonstrated that numerous factors, both modifiable and nonmodifiable, were significantly related to the prevalence of osteoporosis. The modifiable factors identified were participation in physical activity (three to five times per week) and body mass index (BMI). Nonmodifiable factors included age, race, and mother's history. With the aging population, osteoporosis is a growing concern for the medical community. It is suggested that educational strategies are needed to increase awareness of factors that contribute to maintaining bone health among postmenopausal women. Emphasis may be placed on maintaining regular physical activity.

Absorptiometry, Photon↗