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Biomedical subjects

C Roberts

Publications and source records attributed to C Roberts.

At least 289 records · Page 16Linked to original sources
PubMed1991

An analysis of the effects of place of childhood, undergraduate and postgraduate education upon the regional distribution of specialist orthodontic practitioners.

In 1989, a survey of specialist orthodontic practitioners was carried out. Questionnaires were sent to all members of the British Association of Orthodontists who were engaged in full-time specialist practice. This yielded a response rate of 72%. One part of the questionnaire was directed towards details concerned with the practitioner's place of childhood, undergraduate and postgraduate education. The regions in the UK were grouped into two large areas of the 'north' and the 'south'. It was evident that most of the practitioners had received their orthodontic training in the 'south' of England and were employed within the same region. Detailed data analysis was carried out using the Mantel-Haenszel chi-squared test. This revealed that there was a strong association between the place of postgraduate orthodontic training and place of employment of the specialist practitioner (chi 2 = 48.6, P less than 0.00001). The data suggest that one method of reducing the present unequal distribution of the specialist orthodontic practitioner would be to increase the number of postgraduate training places in those regions with low levels of orthodontic manpower.

Adult↗
PubMed1991

Construction and expression of alpha 1-proteinase inhibitor mutants and the effects of these mutations on secretion of the variant inhibitors.

Human alpha 1-proteinase inhibitor (A1Pi) deficiency, associated with the Z variant A1Pi gene, results from defective secretion of the inhibitor from the liver and appears to be a direct consequence of replacement of Glu342 with Lys. To investigate the effect of the amino acid occupying position 342 on secretion of A1Pi, we have used oligonucleotide-directed mutagenesis of A1Pi cDNA to randomly change the codon specifying this amino acid. Since replacement of Glu342 by Lys leads to a change in the predicted secondary structure for this protein, we also tested the possibility that defective secretion of A1PiZ is the result of this type of alteration. For this purpose, site-directed mutagenesis was used to produce sequences encoding A1Pi retaining Glu342 but predicted to have A1PiZ type secondary structure. The effects of 10 different amino acids occupying position 342 on the secretion of A1Pi were determined by pulse-chase experiments and by enzyme-linked immunosorbent assay of medium from transiently transfected COS cells. Results of these studies show that secretion of A1Pi is most efficient when position 342 is occupied by a negatively charged amino acid, efficient but somewhat less so when occupied by a neutral amino acid, and least efficient when a positively charged residue is present. The mutation designed to alter secondary structure had no effect on the secretion of A1Pi. As indicated by immunofluorescence microscopy and mobility of intracellular A1Pi on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, lowered secretion is accompanied by accumulation of A1Pi in the endoplasmic reticulum of the transfected cells. These results are compatible with the ideas that secretion of A1Pi is directly influenced by the amino acid occupying position 342, that a positively charged amino acid in this position is especially detrimental to secretion of this protein, and that the rate-limiting step in the secretion of the altered forms is transport from endoplasmic reticulum to Golgi.

Amino Acid Sequence↗
PubMed1991

The clinical predictability of internal derangements of the temporomandibular joint.

The value of clinical parameters as predictors of the arthrographic findings in patients with temporomandibular joint (TMJ) pain and dysfunction was examined in this study. We developed a series of simplified clinical prediction rules based on previous studies correlating clinical signs and symptoms with arthrographic diagnosis of the condition of the TMJ meniscus. One hundred eighty-six patients with signs and symptoms of TMJ dysfunction were clinically examined before TMJ arthrography. Arthrograms were performed on 246 joints (126 unilateral, 60 bilateral). The rules predicted 91 of the 246 joints to be normal when actually 59 were shown to be normal arthrographically. The rules slightly underpredicted those patients with positive arthrographic findings for internal derangements. Although there were some individual variations in the predictability of unilateral versus bilateral arthrograms (patients), there was very little overall difference, 58% and 60%, respectively. This study confirms previous suggestions that clinical findings alone are not consistently accurate in diagnosing the exact type of TMJ internal derangements depicted by arthrographic criteria.

Adult↗
PubMed1991

The raw oyster consumer--a risk taker? Use of the Behavioral Risk Factor Surveillance System.

We used the 1988 Behavioral Risk Factor Surveillance System in Florida to determine the prevalence of consumption of raw oysters, a vehicle implicated in the transmission of several pathogens. One-third of survey respondents reported ever eating raw oysters. The prevalence was higher for persons 18-49 years old and for males, and, when controlled for age and sex, for persons who reported being cigarette smokers or acute or chronic alcohol drinkers, and driving while intoxicated.

Adolescent↗
PubMed1991

The L5 epitope: an early marker for neural induction in the chick embryo and its involvement in inductive interactions.

The pattern of expression of the carbohydrate epitope L5 was studied during early development of the chick neuroepithelium. Immunoreactivity first appears during gastrulation, at mid-primitive streak stage, and persists until at least 3.5 days of development. The epitope is expressed on all the components of the developing nervous system, both central and peripheral. In immunoblots, the antibody recognises a major component of about Mr 500,000 and several more minor components of lower molecular mass. If a Hensen's node from a donor embryo is transplanted into the area opaca of a host embryo, L5 immunoreactivity appears in the epiblast surrounding the graft. If hybridoma cells secreting the antibody are grafted together with Hensen's node into a host chick embryo, the induction of a supernumerary nervous system is inhibited. We suggest that the L5 epitope is an early and general marker for neural induction and that it may be involved directly in inductive interactions.

Animals↗
PubMed1991

Development of a method for rating nasolabial appearance in patients with clefts of the lip and palate.

Comparison of the outcome of treatment of patients with clefts of the lip and palate can yield valuable pointers for discriminating between beneficial and harmful procedures. The development of a standardized rating scheme to assess the facial appearance of these patients is described. The rating scheme can be used in conjunction with conventional cephalometric analysis and dental arch evaluation. A method is described in which the nasolabial area is masked, thus reducing the influence of the surrounding facial features since it is shown that judges are influenced by general facial attractiveness. An ordinal scale has been evaluated in which four features of the nose and lip are assessed separately and in total by a panel of judges. The nasolabial profile, the nasal symmetry, the nasal form, and vermilion border were assessed using a 5-point scale. Acceptable pooled levels of reliability and reproducibility were obtained. This standardized rating system may be used to differentiate treatment outcome in patients from different treatment centers.

Adolescent↗
PubMed1991

Prevalence of HIV antibody among a group of paraphilic sex offenders.

Serum specimens from 77 paraphilic sex offenders in treatment at a major community-based sexual disorders clinic were examined for human immunodeficiency virus (HIV) infection. In addition to their paraphilic ("sexually deviant") activities, most patients had also had nonparaphilic sexual contacts with consenting adult partners. These patients had engaged in a variety of sexual behaviors that involved real or potential exchange of body fluids. In spite of that fact, data analysis revealed that none of the 77 paraphilic patients was seropositive for HIV infection as assessed by recombinant enzyme-linked immunosorbent assay (ELISA).

Adult↗