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Biomedical subjects

S Cochrane

Publications and source records attributed to S Cochrane.

At least 19 recordsLinked to original sources
PubMed2005

Perceptions of facial aesthetics in two and three dimensions.

The aims of this study were to investigate whether the preferred facial relationship chosen by professionals and the general public is Class I and to ascertain whether viewing two-dimensional (2D) or three-dimensional (3D) images had any effect on the ranking of facial attractiveness. Orthodontists (n = 47), maxillofacial surgeons (n = 25) and members of the general public (n = 78) assessed 2D and 3D facial scans of two males and two females that had been morphed to produce five images reflecting different skeletal patterns: Class I, mild and moderate Class II, and mild and moderate Class III. Each assessor placed the images in rank order of preference, after viewing alternate 2D and 3D image formats for each face. The data were analysed using logistic regression. In 2D, professionals (orthodontists and maxillofacial surgeons) chose Class I as the preferred facial image more frequently than the general public for only one of the four faces. However, in 3D format they chose Class I as the preferred facial image for some subject faces more, and others less, frequently when compared with the general public. The gender of the assessor was not significant when assessing the preferred facial relationship for Class I images in either 2D or 3D formats. The oldest assessors (56+ years) were significantly less likely than the younger age groups to select Class I as the preferred facial relationship in both 2D and 3D. In summary, there was too great a degree of variation to say that a difference between 2D and 3D facial images was evident.

Adolescent↗
PubMed2005

Corticotropin-releasing factor 1 receptor-mediated mechanisms inhibit colonic hypersensitivity in rats.

The potential relationship between stress and irritable bowel syndrome (IBS) symptomatology suggests a possible role for stress-mediating hormones, such as corticotropin-releasing factor (CRF), in the altered perception of stimuli in IBS patients. In previous studies, Wistar-Kyoto (WKY) rats with genetic indices of high anxiety demonstrated colonic hypersensitivity coupled with a high basal level of CRF within the central nervous system. In the current study we tested the hypothesis that a selective, non-peptide CRF1 receptor antagonist, antalarmin, would inhibit hypersensitivity in the WKY rat colon. Colonic sensitivity was determined by monitoring a visceromotor behavioural response during innocuous levels of colorectal distention (30 mmHg). In high anxiety WKY rats we found that antalarmin (20 mg kg-1, i.p.) significantly decreased the visceromotor response induced by colorectal distention. In a second study central administration (i.c.v.) of CRF was used to induce colonic hypersensitivity in lower anxiety Fischer 344 (F-344) rats, and in this model, antalarmin significantly inhibited the CRF-induced colonic hypersensitivity. In summary, a selective CRF1 receptor antagonist, antalarmin, inhibits colonic hypersensitivity apparent in WKY rats or in F-344 rats given a central administration of CRF. Our findings suggest that CRF1 receptor antagonism may represent a novel therapeutic approach for the treatment of IBS.

Animals↗
PubMed1999

Coronary care nurses' clinical decision making.

Increasing acuity of hospitalized persons with cardiac disease places great demands on nurses' decision-making abilities. Yet nursing lags in knowledge-based system development because of limited understanding about how nurses use knowledge to make decisions. The two research questions for this study were: how do the lines of reasoning used by experienced coronary care nurses compare with those used by new coronary care nurses in a representative sample of hypothetical patient cases, and are the predominant lines of reasoning used by coronary care nurses in hypothetical situations similar to those used for comparable situations in clinical practice? Line of reasoning was defined as a set of arguments in which knowledge is embedded within decision-making processes that lead to a conclusion. Sixteen subjects (eight experienced and eight new nurses) from coronary care and coronary step-down units in a large, private, teaching hospital in Minnesota, USA, were asked to think aloud while making clinical decisions about six hypothetical cases and comparable actual case. One finding was that most subjects in both groups used multiple lines of reasoning per case; but they used only one predominantly. This finding highlighted the non-linear nature of clinical decision making. Subjects used 25 predominant lines of reasoning, with intergroup differences on six of them. Where there were differences, experienced nurses used lines of reasoning of lower quality than did new subjects. The type variability in lines of reasoning suggested that multiple pathways should be incorporated into knowledge-system design. One implication of the variability in subjects' line of reasoning quality is that nurses at all levels of expertise are fallible and could benefit from decision support. The finding that subjects tended to use similar lines of reasoning for comparable hypothetical and actual cases was modest validation of subjects' performance on hypothetical cases as representing their decision making in practice. Consequently, there was support for using simulations and case studies in teaching and studying clinical decision making.

Adult↗
PubMed1998

An evaluation of common breast cancer gene mutations in a population of Ashkenazi Jews.

OBJECTIVES: In view of the recent reports of recurrent mutations in BRCA1 and BRCA2 in the Ashkenazi Jewish population, we have undertaken to assess the frequency of these mutations in this population attending for genetic counselling and risk assessment of familial breast cancer. DESIGN: Mutation screening for the 185delAG and the 5382insC mutations in BRCA1 and the 6174delT mutation in BRCA2 was performed on DNA samples from either subjects affected by breast or ovarian cancer or obligate gene carriers. The likelihood of the cancers being hereditary in each family was calculated. SUBJECTS: Blood samples were obtained from 26 affected subjects or obligate gene carriers from 23 Ashkenazi Jewish families, all with a history of either early onset breast or ovarian cancers, or multiple cases of breast or ovarian cancer. RESULTS: Twelve mutations have been identified in the 23 families (52%) of which eight (67%) were the 185delAG mutation, three (25%) were the 6174delT mutation, and one (8%) was the 5382insC mutation. While the majority of these mutations were identified in families with a greater than 50% probability of being hereditary under the CASH segregation model, three mutations were identified in families with a 35% or less probability. CONCLUSIONS: Genetic screening of the recurrent mutations in Ashkenazi Jewish families will lead to the availability of predictive testing in a reasonably large proportion, even if the family history of breast/ovarian cancer is not particularly strong. In our view it is possible to reassure high risk unaffected members of these families, if the screening is negative for these mutations, even if a sample from an affected member of the family is unavailable for previous screening.

Adult↗
PubMed1997

Care of patients undergoing immunoglobulin therapy.

Immunoglobulin infusion is becoming more widely used as treatment for a variety of conditions. This article describes the background and uses of immunoglobulin therapy and the nursing care of patients undergoing this treatment.

Humans↗
PubMed1996

A previously undescribed mutation within the tetramerisation domain of TP53 in a family with Li-Fraumeni syndrome.

We report details of a family with classic Li-Fraumeni syndrome in which there is a mutation in codon 344 of the tumour suppressor gene TP53. Codon 344 is a key residue within the tetramerisation domain, and the amino acid substitution of a proline for a leucine is predicted to have profound implications for tetramerisation and potentially DNA binding. This is the first report of a mutation at this residue in either sporadic tumours or in the germline and the first report of a germline mutation within the tetramerisation domain. The family does not appear to be remarkable in the spectrum of tumours, and there is loss of the wild-type allele in a leiomyosarcoma from the proband. A cell line has been established from the tumour of the proband and cytogenetic and molecular studies carried out, providing an extensive analysis in this family.

Adult↗
PubMed1995

Surveillance of adverse reactions in patients self-infusing intravenous immunoglobulin at home.

This is the first prospective study of adverse reactions occurring in primary-antibody-deficient patients self-infusing intravenous immunoglobulin at home. One hundred nineteen patients, already self-infusing at home, were entered into the study. They had been fully instructed about all aspects of adverse reactions, including their prevention and treatment. In the event of any adverse reaction, a form was completed detailing the product, the dose, the symptoms that occurred and the time they lasted, the rate of infusion, and other relative information such as predisposing factors and any medication taken. The severity of reactions were classified as mild, moderate, or severe. The total number of reactions documented was 19 in 2031 infusions, and all resolved without medical aid. No serious reactions occurred. Excluding those reactions in which predisposing factors were identified, the overall reaction rate was 0.7%. In conclusion the study showed the reaction rate in patients self-infusing intravenous immunoglobulin at home was low following formal training of selected patients at recognized training centers.

Adolescent↗
PubMed1995

Pitfalls in the interpretation of spectral analysis of the heart rate variability during exercise in humans.

The recent use of spectral analysis of the R-R interval variability to assess the autonomic drive during exercise has produced inconsistent results. The purpose of this study was to assess whether the spectral components of the R-R interval variability reflect different mechanisms at rest and during exercise. Autoregressive spectral analysis of the electrocardiographic and breathing signals was performed in 11 healthy young men at rest and during incremental cycle ergometry. The amplitude of respiratory sinus arrhythmia, i.e. the absolute power of the high frequency spectral component, fell at the onset of exercise, consistent with a reduction in cardiac vagal activity. Conversely, the normalized power of the high frequency component, (i.e. the percentage of R-R interval variance due to the respiratory sinus arrhythmia) increased with increasing work rates. The low frequency spectral component of the R-R interval variability, which when expressed in normalized units is believed to reflect cardiac sympathetic activity, was no longer detectable in severe exercise when the adrenergic drive is known to be elevated. In conclusion, autoregressive spectral analysis of the R-R interval variability does not adequately reflect the autonomic changes that occur during incremental exercise. In particular, the evidence indicates that as the cardiac vagal tone falls with increasing levels of exercise, a greater percentage of the residual power of the high frequency component may be due to non-neural mechanisms.

Adult↗
PubMed1994

Mutations in the connexin 32 gene in X-linked dominant Charcot-Marie-Tooth disease (CMTX1)

X-linked dominant Charcot-Marie-Tooth disease (CMTX1) is a peripheral neuropathy which maps to Xq13 and is flanked by the loci DXS106 (Xq11.2-q12) and DXS559 (Xq13.1). Contained within this interval of approximately 2-3Mb of DNA is the gene, connexin 32 (locus designation GJ beta 1). This gene encodes a gap junction protein which is expressed in large quantities within the liver and throughout a range of other mammalian tissues. We have sequenced the coding region of exon 2 of this gene from affected individuals in nine families with CMTX 1 and have found mutations which segregate with the disease in eight of these families. The mutations detected include missense point mutations at codons 15, 60, 63, 208, and 215, a nonsense point mutation at codon 220, deletions of one base in codon 72/3 producing a stop codon 12 codons down stream and a three base pair deletion which can be predicted to result in the loss of a single amino acid. These findings are consistent with the disease CMTX1 being the result of mutations affecting the gene connexin 32 (Cx32).

Amino Acid Sequence↗
PubMed1994

Serum soluble CD23 in patients with hypogammaglobulinaemia.

Serum levels of the soluble form of the low-affinity receptor for IgE (FcERII, CD23) (sCD23) are elevated in autoimmune conditions associated with hypergammaglobulinaemia and B cell hyperactivity. Very high levels of sCD23 are found in patients with B-chronic lymphatic leukaemia (B-CLL) who are, however, frequently hypogammaglobulinaemic. We therefore compared the serum levels of sCD23 in healthy controls (n = 33) with three conditions associated with hypogammaglobulinaemia (HGG) and varying B cell numbers: X-linked agammaglobulinaemia (XLA, n = 12), common variable immunodeficiency (CVI, n = 20) and B-chronic lymphatic leukaemia (n = 33). Serum levels of sCD23 showed a significant correlation with the CD19+ B cell count in both normals and patients with CVI (r = 0.65, P < 0.0001). Amongst the different clinical groups, serum levels of sCD23 were increased in the order XLA < CVI < normals < CLL (medians 2.5, 7.7, 11.1 and 540, respectively; P < 0.001 for all comparisons except CVI versus normals P < 0.03 in a one-tailed test). In the CVI group, serum sCD23 was lowest amongst four patients with low B cell numbers. There was no overlap in sCD23 between patients with XLA and this subgroup of CVI patients. Serum sCD23 is, therefore, derived predominantly from B cells, and is significantly related to the peripheral blood B cell count.

Agammaglobulinemia↗
PubMed1994

X linked Charcot-Marie-Tooth disease (CMTX1): a study of 15 families with 12 highly informative polymorphisms.

X linked dominant Charcot-Marie-Tooth disease (CMTX1) has previously been localised to Xq13-21. Fifteen families were studied using 12 highly informative polymorphisms in the pericentric region of the X chromosome. Phase known recombinations in these families localise the X linked dominant CMT gene to the region distal to DXS106 (Xq11.2-12) and proximal to DXS559 (Xq13.1). These markers flank approximately 2 to 3 Mb of DNA to which GJB1 and CCG1 have already been mapped. A recent report of mutations in the GJB1 gene in subjects with CMTX1 makes this a strong candidate gene.

Cell Cycle↗
PubMed1994

A mark of approval. Patient satisfaction with an i.v. self-infusion teaching programme.

1. Self-infusion of IV immunoglobulin at home has many advantages for patients and their partners/carers. 2. To operate safely, home therapy programmes must include sufficient patient teaching and support. 3. Established home therapy patients were questioned on the service provided for them. 4. Overall, the service provided is perceived to be very good.

Fluid Therapy↗
PubMed1994

Laryngeal paralysis-polyneuropathy complex in young Dalmatians.

Clinical, morphologic, and morphometric findings are reported in 14 young Dalmatians with laryngeal paralysis. Neurologic signs, including megaesophagus, were observed in 13 of 14 dogs. Electromyographic abnormalities included fibrillation potentials and positive sharp waves in laryngeal, esophageal, facial, and distal appendicular muscles. Neurogenic atrophy was detected in intrinsic laryngeal and appendicular skeletal muscles. A diffuse, generalized polyneuropathy, dominated by axonal degeneration, was observed in recurrent laryngeal and appendicular peripheral nerves. Results of quantitative studies, using single teased fiber and cross-sectional nerve preparations, indicated that changes were more severe in distal parts of peripheral nerves, with preferential loss of medium sized (5.5 to 8 microns) and large-caliber (8.5 to 12 microns) myelinated nerve fibers. Ultrastructural alterations were observed in myelinated and unmyelinated nerve fibers. The term laryngeal paralysis-polyneuropathy complex is proposed for this apparent dying-back disorder, which is clinically, electrophysiologically, and pathologically different from laryngeal paralysis in young Bouvier des Flandres and Siberian Huskies. Prognosis for Dalmatians with laryngeal paralysis-polyneuropathy complex is guarded to poor. The condition is believed to be inherited.

Animals↗
PubMed1990

Knowing what to think by knowing who you are: self-categorization and the nature of norm formation, conformity and group polarization.

We contrast two theoretical approaches to social influence, one stressing interpersonal dependence, conceptualized as normative and informational influence (Deutsch & Gerard, 1955), and the other stressing group membership, conceptualized as self-categorization and referent informational influence (Turner, Hogg, Oakes, Reicher & Wetherell, 1987). We argue that both social comparisons to reduce uncertainty and the existence of normative pressure to comply depend on perceiving the source of influence as belonging to one's own category. This study tested these two approaches using three influence paradigms. First we demonstrate that, in Sherif's (1936) autokinetic effect paradigm, the impact of confederates on the formation of a norm decreases as their membership of a different category is made more salient to subjects. Second, in the Asch (1956) conformity paradigm, surveillance effectively exerts normative pressure if done by an in-group but not by an out-group. In-group influence decreases and out-group influence increases when subjects respond privately. Self-report data indicate that in-group confederates create more subjective uncertainty than out-group confederates and public responding seems to increase cohesiveness with in-group - but decrease it with out-group - sources of influence. In our third experiment we use the group polarization paradigm (e.g. Burnstein & Vinokur, 1973) to demonstrate that, when categorical differences between two subgroups within a discussion group are made salient, convergence of opinion between the subgroups is inhibited. Taken together the experiments show that self-categorization can be a crucial determining factor in social influence.

Adolescent↗
PubMedDate not supplied

Consortium fine localization of X-linked Charcot-Marie-Tooth disease (CMTX1): additional support that connexin32 is the defect in CMTX1.

Charcot-Marie-Tooth (CMT) disease is the most common form of inherited motor and sensory neuropathy. X-linked CMT (CMTX1) has been localized to the pericentric region of the X chromosome. Recently, mutations have been defined in the connexin32 gene that cosegregate with the CMTX1 phenotype in several families. The present paper presents the results of an international consortium to fine map the gene for CMTX1 to a small segment of Xq12-13. The linkage data, together with the molecular genetic studies, support the hypothesis that connexin32 is the genetic defect in CMTX1.

Charcot-Marie-Tooth Disease↗