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Biomedical subjects

M Carr

Publications and source records attributed to M Carr.

At least 37 records · Page 2Linked to original sources
PubMed1995

Determination of oestrogen responsiveness of breast cancer by competitive reverse transcription-polymerase chain reaction.

Competitive polymerase chain reaction assays have been developed for the quantitation of oestrogen receptor mRNA and two oestrogen-regulated mRNAs (progesterone receptor and pNR-2/pS2) in breast cancer cells. These assays are more sensitive than traditional hybridisation techniques, do not require the use of radioisotopes, measure absolute amounts of messenger RNAs and can be used to measure the expression of mRNAs in small numbers of tumour cells obtained by fine-needle aspiration (FNA). These assays should prove useful for predicting the hormone responsiveness of breast cancer from tumour cells obtained by FNA at diagnosis and could be particularly useful in the management of elderly/frail patients who receive primary tamoxifen, or in other patients for whom tumour tissue for standard biochemical measurements is not available.

Base Sequence↗
PubMed1995

Evidence for nosocomial transmission of Candida albicans obtained by Ca3 fingerprinting.

The moderately repetitive sequence Ca3 was used to fingerprint Candida albicans isolates from 32 patients hospitalized for more than 3 days, 17 recent admissions or outpatients, and 8 recently readmitted patients and 10 commensal isolates from the community in Wellington, New Zealand, plus isolates from 21 hospitalized patients, 26 outpatients or recent admissions, 4 recently readmitted patients, and 10 healthy individuals in the community in Auckland, New Zealand. In Wellington, isolates from patients hospitalized in Wellington Hospital for more than 3 days were genetically significantly less diverse than were isolates from outpatients or recent admissions or isolates from healthy individuals in the community. In addition, two clusters of genetically similar strains were isolated from hospitalized patients significantly more often than from other individuals. These observations provide evidence (albeit indirectly) for nosocomial transmission of hospital-specific C. albicans strains. In contrast, no indication of hospital-specific transmission of C. albicans was found in Auckland Hospital. Since these results were obtained under conditions in which no candidiasis outbreak occurred in either hospital, they also suggest that Ca3 fingerprinting may be a useful tool in preventive nosocomial infection control programs, allowing assessment of the extent of C. albicans transmission occurring in a hospital.

Adolescent↗
PubMed1994

Crystal structure of a disulfide-linked "trefoil" motif found in a large family of putative growth factors.

Porcine pancreatic spasmolytic polypeptide (PSP) belongs to a large family of homologous growth factor-like polypeptides characterized by a disulfide-linked "trefoil motif," duplicated and conserved in various family members. PSP contains two trefoil motifs, has several pharmacological actions on the gut, and has growth factor properties on epithelial cells in vitro. The human PSP analogue, human spasmolytic polypeptide, appears to be involved in many regenerative situations and, especially, in healing gastrointestinal ulcers. One member of the trefoil family, pS2, is secreted in approximately 50% of estrogen-dependent human breast carcinomas, which has led to its use as a tumor prognostic marker. Both pS2 and human spasmolytic polypeptide are also widely expressed in chronic gastrointestinal ulcerative conditions such as Crohn disease. Here we report the three-dimensional structure at 2.6-A resolution of a trefoil-containing protein, namely PSP, purified from porcine pancreas. The structure shows two homologous domains that share a supersecondary structure and disulfide bond pattern. The two domains pack asymmetrically giving rise to a number of protruding loops, exposed clefts, and an unusual electrostatic surface potential. Knowledge of the structure of PSP should allow the design of mutants to investigate further the function of PSP and other trefoil-containing peptides.

Amino Acid Sequence↗
PubMed1994

Incongruous item generation effects: a multiple-cue perspective.

In a series of studies, generation effects were obtained under encoding conditions designed to induce incongruous, unrelated item generation. Experiments 1 and 2, using free- and cued-recall measures, respectively, provided evidence that this unrelated generation effect was due to response-specific processing. Experiment 3 demonstrated a lack of relation between free recall and indices of clustering. A preliminary protocol study suggested that Ss generate multiple items in their search for appropriate unrelated responses. In Experiments 4 and 5, conditions designed to produce more extensive multiple generations demonstrated enhanced free recall. These results supported a multiple-cue account of facilitated recall for incongruous item generation. The multiple-cue perspective is consistent with traditional conceptualizations of memory, such as the principle of congruity, and contemporary distinctions between cue-target relational and item-specific processing.

Adult↗
PubMed1994

Is being smart everything? The influence of student achievement on teachers' perceptions.

The purpose of this project was to explore the accuracy and predictors of teachers' perceptions of their students' metacognition, self-concept, and attributional beliefs. Nineteen third grade teachers each nominated six children from their classrooms based on the children's maths abilities (high, medium, low). The children were tested on metacognitive knowledge, self-concept, and attributional beliefs. Teachers completed questionnaires estimating each child's metacognitive abilities, academic self-concept, and attributional beliefs about the reasons underlying academic success and failure. Analyses indicated that teachers' perceptions were biased by children's abilities, as higher ability children were portrayed more favourably on all variables. Regressions of teachers' perceptions on children's scores revealed that teachers were moderately accurate in their ratings of children's metacognitive abilities, but not of their attributional beliefs or self-concepts. Implications for metacognitive and motivational models of the learner are discussed.

Achievement↗
PubMed1994

Dangerous brew.

Polypharmacy, the use of multiple medications concurrently, is common among the elderly. Beers and Ouslander report that older North Americans consume 4.5 medications on average at any one time. In Canada, seniors take 25 per cent of all prescriptions but comprise only 12 per cent of the population. And according to Cartwright, 50 per cent of Britain's seniors take two or more medications on a regular basis.

Aged↗
PubMed1993

Shapes of cells spreading on fibronectin: measurement of the stellation of BHK21 cells induced by raising cyclic AMP, and of its reversal by serum and lysophosphatidic acid.

In common with many other animal cells in culture, BHK21, CHO and NIH-3T3 cells adopt bizarre stellate or arborized shapes when exposed, in the absence of serum, to agents which increase cytoplasmic cyclic AMP (cAMP). Dibutyryl cAMP, 3-isobutyl-1-methylxanthine, 5'-deoxy-5'-methylthioadenosine, cholera toxin and the invasive adenylate cyclase from Bordetella pertussis all induce similar shapes. Time lapse video recording of BHK21 cells spreading on fibronectin shows that stellate shapes are generated by outgrowth of neurite-like processes led by small fans of ruffling membrane. These structures stain strongly for F actin, and their outgrowth is completely inhibited by cytochalasin D. Thus if stellation is caused by microfilament depletion, this must be selective for subsets of microfilaments. We have quantified the shape changes of BHK21 cells using the parameter dispersion. They are prevented by low concentrations (1% by volume and below) of bovine sera. The inhibitory component of foetal bovine serum acts humorally, behaves as a macromolecule and is itself inhibited by suramin, but platelet-derived growth factor, insulin, vasopressin and bradykinin are inactive. The inhibitory activity of serum may be due to phospholipids, since it can be replaced by lysophosphatidic acid in the presence of serum albumin.

3T3 Cells↗
PubMed1993

Reflective monitoring in lonely adolescents.

Deficient social skills may be a primary contributor to chronic loneliness during adolescence. Specifically, adolescents at risk of becoming chronically lonely may have trouble reflecting on the appropriateness of their behavior, and learning from their actions. This inability to monitor and reflect on behavior may promote the development of the social, affective, and behavioral problems characteristic of chronic loneliness. Hence, some instances of chronic loneliness may be understood in terms of a developmental psychopathological model which delineates their cognitive, behavioral, and affective components. Dysfunctional familial or peer group interactions in childhood may contribute to the development of a reflective monitoring deficit.

Adolescent↗
PubMed1992

The effect of obstruction on the developing bladder.

Congenital bladder obstruction causes significant immediate and long-term consequences yet its pathophysiology remains poorly understood. A model of early fetal bladder obstruction in sheep has been developed to study the response of the developing bladder to high grade obstruction, with particular emphasis on the regulation of growth and development. Congenital bladder obstruction was produced in fetal sheep at 60 days of gestation and studied at 95 days of gestation (14 sheep) or term (12 sheep). A total of 24 age-matched normal sheep served as controls. Bladders were analyzed by total weight, stereological estimation of smooth muscle cell size, number and total mass, deoxyribonucleic acid concentration, muscarinic cholinergic receptor density, myosin isoform analysis and/or passive cystometrics. Congenital bladder obstruction caused a 4.6 times increase in bladder weight at term reflecting a 5.8 times increase in smooth muscle mass. This increase was predominantly that of cellular hypertrophy and less so of hyperplasia, based upon increased cell volume, increased protein-to-deoxyribonucleic acid ratio, and no significant increase in total cell number. Muscarinic cholinergic receptor number per smooth muscle cell increased 3.2 times but it did not change relative to myosin content. The ratio of myosin heavy chain isoforms SM1:SM2 is developmentally regulated and was seen to change from 1.6 at 100 days of gestation to 1.13 at term in normals. After 5 weeks of obstruction SM1:SM2 was 1.27 and it was 1.25 at term, indicating an effect on the developmental regulation of smooth muscle. Rapid fill cystometry in vivo measured the rate of stress relaxation to assess accommodative properties. The half-decay time was increased in all 3 obstructed bladders tested to greater than 15 seconds at 50% capacity (normal less than 5 seconds), suggesting reduced compliance. This study shows that an in utero model of bladder obstruction is feasible. Congenital bladder obstruction produces a variety of structural, biochemical and functional changes in the developing bladder indicative of alterations in the regulation of growth and differentiation.

Actins↗
PubMed1992

Cranio-orbito-zygomatic measurements from standard CT scans in unoperated Crouzon and Apert infants: comparison with normal controls.

Cranio-orbito-zygomatic measurements taken from standard axial computed tomographic (CT) scans of unoperated patients with Crouzon syndrome (6 males, 14 females) and Apert syndrome (6 males, 10 females) under 1 year of age were compared to each other and to normal controls (40 males, 35 females). Fifteen cranio-orbito-zygomatic variables were measured and repeated. Means and standard deviations were computed for each sex, and means were pooled since they were not significantly different. Correlation coefficients for repeat measures (intra-observer error) of each variable showed good reproducibility. Only the lateral orbital wall angle differed between the syndromes (p = .034), suggesting that upper facial differences (as measured by these variables) do not manifest themselves at this young age. All measurements for both syndromes, except one, were outside the 95 percent confidence range for age-matched controls. Measurements taken from standard CT scans provide an objective comparison between specific syndromes and the normal population.

Acrocephalosyndactylia↗
PubMed1991

The role of the kidney in lung growth and maturation in the setting of obstructive uropathy and oligohydramnios.

The contribution of the kidneys to lung development, which includes growth and maturation, is uncertain but it appears to be complex. Obstructive uropathy with oligohydramnios produces pulmonary hypoplasia characterized by small lungs (decreased lung volume/body weight) and retarded maturation (reduced total airspace). Lung growth and maturation were studied in a model of early gestation obstructive uropathy to understand better their relationship and their prenatal regulation. Of 26 fetal sheep studied at near term (135 days of gestation) 9 had bladder obstruction created at 60 days of gestation, 11 had bladder obstruction at 60 days with in utero decompression at 95 days, and 6 served as controls and shams. Amniotic fluid volume was measured, kidneys were prepared and evaluated histologically, lungs were inflation-fixed and volumes were measured, and airspace volume percentage was measured morphometrically. Experimental and serendipitous variations in the condition of the kidneys and amniotic fluid at delivery permitted an analysis of the contribution of the kidneys and the amniotic fluid to lung growth and maturation. Impairment of growth and maturation was dissociated in certain animals, and this dissociation was referable to the histological status of the kidneys and the presence or absence of amniotic fluid at delivery. Growth was normal when amniotic fluid was present or likely to have been present in late gestation, even with structurally damaged kidneys. With severe renal damage amniotic fluid was not restored even with in utero decompression and it resulted in severely impaired lung growth. Maturation was normal only in the presence of amniotic fluid and intact kidneys. The dissociation of lung growth and structural maturity suggests their independent regulation. The data suggest that the kidneys are important in early lung growth, while the presence of amniotic fluid contributes to growth later in gestation. Lung maturity requires both factors, suggesting a primary kidney contribution with the amniotic fluid acting in a permissive or supportive role.

Amniotic Fluid↗
PubMed1990

Fatal attraction: the ethical and clinical dilemma of patient-therapist sex.

This article reviews the existing literature on the subject of patient-therapist sexual contact. Seven point one percent to 10.9% of male therapists and 1.9% to 3.5% of female therapists admit to engaging in intimate contact with patients. Offenders tend to justify their behaviour as being at least innocuous if not beneficial for the patients. The consequences to the patients include increased psychological and psychosomatic complaints, greater mistrust and anger towards men, hospitalization and suicide. Transference and countertransference issues which account for this behaviour are explored as is the issue of post-termination involvement. Education of physicians and residents concerning the temptations and dangers of this type of contact is strongly recommended.

Attitude of Health Personnel↗
PubMed1989

Prevalence of cryptosporidiosis in patients undergoing endoscopy: evidence for an asymptomatic carrier state.

PURPOSE: We sought to determine the presence of the parasite cryptosporidium in the duodenal aspirates of patients undergoing routine upper gastrointestinal endoscopy. PATIENTS AND METHODS: The study consisted of 169 patients undergoing upper endoscopy or endoscopic retrograde cholangiopancreatography. Immunocompromised patients were not included in the study population. Samples were aspirated from the second portion of the duodenum. Biopsy specimens were also obtained. Three randomly passed stool samples were obtained from 75% of the patients who were found to have cryptosporidium in the duodenum. RESULTS: Overall, cryptosporidium oocysts were identified in 12.7% of patients. There was no significant difference in the prevalence of the parasite in any subgroup of procedure or symptom complex. Half of those (46.7%) with positive aspirates had demonstrable cryptosporidium in stool samples, although none of the patients had diarrhea. No patient had detectable cryptosporidium in biopsy samples of the duodenum. CONCLUSION: The findings suggest a surprisingly high asymptomatic carrier rate for cryptosporidium.

Carrier State↗
PubMed1987

Prenatal diagnosis and management of congenital defects of the anterior abdominal wall.

Between the years 1980 and 1985, 25 cases of anterior abdominal wall defects were identified within the University of Toronto Perinatal Complex. There were 17 cases of omphalocele and eight cases of gastroschisis. Associated anomalies were found in 71% of infants with omphalocele and 50% with gastroschisis. They were the major cause of neonatal death. Prematurity was the second most common cause of death. The neonatal death rate was 59% in omphalocele and 38% in gastroschisis; the prematurity rates were 53% and 50%, respectively. In omphalocele, there was a 47% cesarean section rate, with a 50% neonatal death rate. Vaginal delivery was associated with a 67% death rate. In gastroschisis, there was a 50% cesarean section rate, with a 50% neonatal death rate. Vaginal delivery was associated with a 25% death rate. There is no evidence that cesarean section offers improved neonatal survival.

Abdominal Muscles↗
PubMed1987

Forecasting cataract surgeries and intraocular lens implantation to 1990 using a model of population dynamics.

Extending the recently observed dramatic growth rates of cataract surgery and intraocular lens implantation into the future is not necessarily valid because of changes in population size, new incidence of cataracts, and rates of treatment for patients diagnosed in current as well as in previous years. Accelerated treatment of the pool of previously diagnosed patients caused a sharp growth in cataract surgery since 1980, but at the same time reduced patients and thus the potential for continued high growth rates. This paper describes a model that produces forecasts through explicit consideration of the many aspects of population dynamics. It provides an opportunity to examine how forecasts might vary under different assumptions about advances in medical technology.

Adult↗
PubMed1986

Hemopericardium resulting from attempted internal jugular vein catheterization: a case report and review of complications of central venous catheterization.

An unusual case of hemopericardium and presumed fatal cardiac tamponade complicating attempted right internal jugular vein catheterization by the posterior approach is reported. Reports of complications in a series of internal jugular vein catheterizations using various approaches (posterior, central, anterior, supraclavicular) and subclavian vein catheterizations are reviewed. Internal jugular vein catheterization is not necessarily safer than subclavian vein catheterization: numerous factors determine success rate and complication rate in central venous catheterizations.

Aged↗