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Biomedical subjects

D Alexander

Publications and source records attributed to D Alexander.

At least 127 records · Page 7Linked to original sources
PubMed1985

Occupational stress, personal strain, and coping among residents and faculty members.

Differences in ratings by 155 individuals at four levels of medical experience (faculty members and first-, second-, and third-year residents) on measures of occupational stress, personal strain, and availability of coping resources were examined. Multivariate and univariate analyses of data indicated significant differences in the measures among the experience levels. Measures of the availability of coping resources reflected the major source of differences, with the first-year residents reporting significantly fewer overall coping resources than faculty members. No significant differences were detected among the four groups on overall measures of occupational stress and personal strain. There were differences between first-year residents and faculty members on the subscales measuring physical environment stress, physical strain, recreation, and self-care. The findings suggest that residency education interferes with first-year residents' abilities to cope and places their physical well-being at risk. The findings support the need for residents to employ coping strategies during the residency years and provide empirical guidance regarding the kind of coping strategies needed.

Adaptation, Psychological↗
PubMed1985

New approaches to the study of cellulose biosynthesis.

Examples of a variety of approaches for studying the mechanism and regulation of cellulose biosynthesis are presented. Attempts to demonstrate conclusively a cellulose synthase activity using membrane preparations derived from higher plants have not been successful; the predominant UDP-glucose: beta-glucan-beta-glucosyltransferase detected in these preparations is a beta-(1----3)-glucan synthase that is dependent upon Ca2+ and a beta-glucobiose, such as laminaribiose or cellobiose, for activity. Xyloglucan glucosyltransferase activity is detected in all plant preparations examined and, in cotton fibres, the activity of this enzyme correlates well with the level of xyloglucan found in the fibre. Low activity for a Mg2+-dependent beta-(1----4)-glucan synthase is found in extracts from soybeans and mung beans, but not cotton fibres; this enzyme could represent either a dissociated form of xyloglucan glucosyltransferase or a partially latent form of cellulose synthase. In vitro translation of RNA from developing cotton fibres shows notable increases in the level of several relatively abundant translatable mRNAs associated with the time of onset of secondary-wall cellulose synthesis. In order to determine whether these apparent changes in gene expression represent enhanced expression of specific genes required for cellulose synthesis, several strategies are being developed for identification of specific polypeptides required for this process. One strategy involves the successful development of a technique for detection of glucan synthase activity in acrylamide gels, a technique that should prove useful for characterization of the polypeptide composition of such enzymes. We have also synthesized a photoaffinity analogue of 2,6-dichlorobenzonitrile (DCB), a potent and specific inhibitor of cellulose synthesis. The analogue is also an effective inhibitor in vivo, and upon ultraviolet irradiation of extracts in the presence of the radioactive analogue, we observe a relatively specific labelling of a polypeptide of 18 X 10(3)Mr. Finally, we have studied the spatial regulation and structural requirements for cellulose synthesis in internode cells of the alga Chara corallina. Cellulose deposition in vivo shows spatial localization, which correlates with acid and base bands along the cell. Using internodes perfused with solutions containing UDP-[14C]glucose and subsequently ligated, we were able to demonstrate synthesis of a highly insoluble cell-wall-localized glucan, thus offering hope that Chara can be developed as another useful system for studying the mechanism and regulation of cellulose synthesis.

Cell Membrane↗
PubMed1984

Interstitial deletion of band q12 of chromosome 5.

A six-months-old girl is presented with psychomotor retardation and multiple congenital malformations. The karyotype done on peripheral blood lymphocytes and skin fibroblasts was found to be 46,XX del(5)( q11q13 ). The parents are consanguineous. Their karyotypes were normal. The genes for Arylsulphatase B and Hexosaminidase B are not located in band 5q12 .

Abnormalities, Multiple↗
PubMed1984

Five related Lebanese individuals with high plasma lysosomal hydrolases: a new defect in mannose-6-phosphate receptor recognition?

Five healthy related individuals in 3 generations of a Lebanese family have been found to have highly elevated plasma lysosomal enzyme levels inherited as a dominant Mendelian trait. The same enzymes in other extracellular fluids were within normal limits. While the pattern and extent of plasma enzyme elevation was similar to that found in mucolipidoses II and III, the physicochemical properties of the elevated enzymes were different from those of both control and I-cell disease plasma. Secretion of lysosomal hydrolases into cell media by fibroblasts from one of the individuals was increased two to seven times more than that from controls. The results suggest faulty recognition between lysosomal hydrolases and mannose-6-phosphate receptors. This could be caused by a defect either in the phosphodiesterase that normally uncovers mannose-6-phosphate hydrolase markers or in the mannose-6-phosphate receptor itself.

Adolescent↗
PubMed1984

Arthrodesis for failed arthroplasty of the hip.

The results of Girdlestone arthroplasty after failure of total hip arthroplasty have been found to be functionally poor in the physiologically young patient. The authors have evaluated 14 patients who were treated by hip arthrodesis following repeated failed arthroplasty. The average number of previous procedures was 2.6. Seven were infected prior to arthrodesis. A modified A.O. technique was used in all cases and was followed by hip spica immobilization. The average age of the patients was 38 years. All but one were men. Thirteen of the patients healed their arthrodesis primarily. Pain relief was excellent and most patients were able to return to their original jobs, in contrast to the results in patients with Girdlestone arthroplasty. Osteotomy or arthrodesis is preferred to total hip arthroplasty in the young, active patient with unilateral osteoarthritis. Arthrodesis is also possible and has a high rate of functional success after failed arthroplasty, infected or noninfected.

Acetabulum↗
PubMed1983

Scoliotic spinal anthropometry.

Three-dimensional spinal data were collected from AP and lateral spinal radiographs of 24 female adolescent idiopathic scoliotics. Vertebral body end-plate eccentricity (AP vertebral body width divided by lateral vertebral body width) was measured and found to be minimized at the apex of the scoliotic curve in approximately 70 percent of the subjects. Measurement of end-plate eccentricity is suggested as a possible method for assessment of vertebral body rotation in scoliotic subjects.

Adolescent↗
PubMed1983

Response of age forty and over military personnel to an unsupervised, self-administered aerobic training program.

The Army recently extended mandatory physical training and testing to include personnel 40 yrs of age and older. The purpose of this study was to describe the profile of aerobic fitness in a representative group from this age population and to evaluate the response of such a group to a self-administered, unsupervised training program. Maximal oxygen uptake (Vo2 max) and percent body fat (%BF) were assessed in 260 military personnel (40-53 yrs of age) before and after 6 mo of physical training consisting of a progressive walk/run mode of exercise. Before training the mean +/- S.D. for Vo2 max and %BF for all subjects was 38.1 +/- 6.2 ml/kg . min and 26.1 +/- 4.7%, respectively. Subjects were divided into three groups based upon their initial level of physical activity determined by interview as follows: inactive, moderately active and active. Upon retesting after 6 mo, 40% of the inactive group had not participated to any appreciable degree in the program and subjects of this group who did participate showed only a slight and insignificant increase (4.4%) in Vo2 max. The pretraining level of Vo2 max for the total population studied was similar to that reported in other studies on comparably aged subjects. However, changes with training were well below those seen with supervised group programs of 6 mo duration.

Adult↗
PubMed1982

Disease epidemiology and earthquake disaster. The example of Southern Italy after the 23 November 1980 earthquake.

This paper describes aspects of the epidemiological situation following the November 1980 earthquake disaster in Campania and Basilicata, southern Italy. First, population displacements and the fluctuating state of homelessness after the catastrophe are described. Secondly, the level of medical provision prior to the disaster is assessed and damage caused by the earthquake to the medical care and sanitation infrastructures is outlined. Thirdly, the publicity given by news media to the threat of disease is examined and compared with the official government reaction, which took the form of emergency medical provision and intervention against the supposed threat of disease. The national epidemiological surveillance system, which was set up during the aftermath of the disaster, is outlined and some of its results, describing the post-impact epidemiological situation in the disaster zone, are examined. Despite the chaotic situation following the earthquake and the publicity given to the threat of disease outbreaks, there were no serious epidemics and the hospital system was able to cope with the aftermath. The government program of vaccinating survivors and relief volunteers can therefore be seen as an over-reaction to the prevailing situation, although continuing disease surveillance was probably a wise precaution.

Communicable Disease Control↗
PubMed1979

Injuries in Rugby League football.

All injuries occurring in the top three grades of a New South Wales club were documented over a one-year period (1978). Two hundred and four injuries were recorded and over half of these injuries (51%) occurred in the lower limbs. The injury rate was calculated at one injury per 3.6 man hours of play. There was a significant difference in the type of injury sustained by forwards and backs, the forwards receiving more cuts, bruises and haematomas, and fewer joint injuries. This difference is probably because of the nature of the game played by these subgroups.

Athletic Injuries↗