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Biomedical subjects

R J Mitchell

Publications and source records attributed to R J Mitchell.

At least 91 records · Page 5Linked to original sources
PubMed1983

Red cell antigen, plasma protein and red cell enzyme polymorphisms in the island of Tasmania.

Blood specimens from 651 blood donors registered with the Hobart division of the Red Cross Blood Transfusion Service of Tasmania were examined for six red cell antigen systems, as well as two plasma protein and three red cell enzyme polymorphisms. The most distinctive feature is the relatively high frequency of the Rh haplotype cde. Subdivision of the sample, permitted via questionnaire data, indicated that donors born overseas exhibited the greatest differences from those born in Tasmania, but none were significant at the 5% level. Overall gene frequencies in Tasmanian donors, except for the Rh system, were very similar to those reported for Melbourne donors, and clearly reflect the known predominance of British and Irish immigrants throughout the period of white settlement on the island.

Australia↗
PubMed1982

ABH secretion in Northumberland, England.

The frequency of ABH non-secretory (29.2%) in a sample of 1,752 school-children resident in Northumberland is very similar to those reported in neighbouring populations. Allocation of individuals among four regions of Northumberland on the basis of residence and birthplace revealed no overall heterogeneity. However, those born in the south-east region exhibited a significantly (p less than 0.05) higher frequency of non-secretors than those born elsewhere. This suggests that ABH secretion can be added to the list of polymorphisms including ABO, Hp phenylthiocarbamide tasting and skin colour that distinguish the population of south-east Northumberland from the rest of the county.

ABO Blood-Group System↗
PubMed1982

A practical evaluation system for preclinical restorative dentistry.

This paper describes an attempt to build a functional evaluation system incorporating several aspects of the evaluation process that have been advocated in educational research. The system--which employs performance criteria, analytical grading, rater calibration, student self-evaluation, mark-sense grading forms, and computer tabulation--has been in effect for six years at the Medical College of Georgia School of Dentistry. The main advantages of this approach are prompt, specific feedback to students concerning their performance on practical exams and diagnostic aids to course directors. In addition, rater calibration has resulted in interrater reliability usually around 0.80 or higher. The major disadvantages of the system are the faculty time required and dependence on a computer.

Clinical Competence↗
PubMed1981

Microsurgical anatomy of the middle cerebral artery.

The microsurgical anatomy of the middle cerebral artery (MCA) was defined in 50 cerebral hemispheres. The MCA was divided into four segments: the M1 (sphenoidal) segment coursed posterior and parallel to the sphenoid ridge; the M2 (insular) segment lay on the insula; the M3 (opercular) segment coursed over the frontoparietal and temporal opercula; and the M4 (cortical) segment spread over the cortical surface. The Sylvian fissure was divided into a sphenoidal and an operculoinsular compartment. The M1 segment coursed in the sphenoidal compartment, and the M2 and M3 segments coursed in the operculoinsular compartment. The main trunk of the MCA divided in one of three ways; bifurcation (78% of hemispheres), trifurcation (12%), or division into multiple trunks (10%). The MCA's that bifurcated were divided into three groups: equal bifurcation (18%), inferior trunk dominant (32%), or superior trunk dominant (28%). The MCA territory was divided into 12 areas: orbitofrontal, prefrontal, precentral, central, anterior parietal, posterior parietal, angular, temporo-occipital, posterior temporal, middle temporal, anterior temporal, and temporopolar. The smallest cortical arteries arose at the anterior end and the largest one at the posterior end of the Sylvian fissure. The largest cortical arteries supplied the temporo-occipital and angular areas. The relationship of each of the cortical arteries to a number of external landmarks was reviewed in detail.

Cerebral Arteries↗
PubMed1979

A study of high copper amalgams. IV. Formation of eta Cu-Sn (Cu6Sn5) crystals in a high copper dispersant amalgam matrix.

In an HCD amalgam, eta Cu-Sn crystals were found dispersed within gamma1 matrix areas. Previously, eta Cu-Sn phase was thought to form only as part of a reaction zone surrounding Ag-Cu dispersant particles. The eta Cu-Sn crystals found in matrix areas of this HCD amalgam are smaller and more widely scattered than eta Cu-Sn crystals dispersed in the gamma1 matrix of HCSC amalgams.

Chemical Precipitation↗
PubMed1977

Phenylthiocarbamide (PTC) taste sensitivity in selected populations of the Isle of Man and Cumbria.

PTC taste thresholds were determined using a modification of the Harris and Kalmus sorting technique for 854 Cumbrian schoolchildren and 699 individuals from the Isle of Man. A non-taster frequency of 19.7 percent was observed in the Cumbrian sample compared with a frequency of 27.8 per cent in that from the Isle of Man. Analysis of taste threshold distributions revealed significant variability, both within and between these two samples. Evidence of significant regional heterogeneity was detected in Cumbria but not in the Isle of Man. Finally, these two series were compared with data from neighbouring regions of the British Isles and Scandinavian populations.

Adolescent↗
PubMed1977

Red-green colour blindness in the Isle of Man and Cumbria.

The frequencies of red-green colour-blind males in the indigenous population of two regions of Britain, the Isle of Man (5.6 per cent) and Cumbria (5.0 per cent), do not readily fit into the pattern of a SW-NE gradient in the frequency of the colour-blind gene in Britain suggested by earlier studies. Frequencies of red-green colour-blind females are also given for these two populations.

Adolescent↗
PubMed1976

The red blood cell esterase D polymorphism in Europe and Asia.

Several regional series from Britain and 3 Asian series were typed for the Esterase D polymorphism. It was found that haemolysates up to 5 years old could be reliably typed when prepared from washed anticoagulated red blood cells. Lysates prepared from blood clots do not retain Esterase D activity quite as well. The Manx population has higher Esterase D 2 gene frequencies than neighbouring populations. A Nepalese population exhibits the highest Esterase D 2 gene frequency so far recorded. The other series presented supplement or confirm results already published.

Asia, Western↗
PubMed1976

Blood groups antigens, plasma protein and red cell isoenzyme polymorphisms in south-west Scotland.

Blood donor specimens from South-west Scotland were analysed for the following polymorphisms: ABO, Rhesus (D), Haptoglobin, Transferrin, Immunoglobulin (GM), RBC acid phophatase, RBC phosphoglucomutase and RBC adenylate kinase. Genetic differences exist between the regions in S.W. Scotland and between S.W. Scotland and other Irish and Irish Sea regions. This variability is detailed and discussed. The results are mapped by converting the data into distance values and by using a nonmetrical scaling technique. Overall the present S.W. Scotland data are similar to Cumbrian and Manx results and dissimilar to the Irish data.

ABO Blood-Group System↗
PubMed1976

ABH secretion in populations of the British Isles.

Saliva specimens were collected from 163 Manx and 994 Cumbrian individuals and tested for secretor group. The findings confirm the pattern of variability in non-secretor frequencies reported in populations of the British Isles. A possible explanation for this distribution of secretor groups is suggested. The Cumbrian sample is also examined for intra-regional heterogeneity.

ABO Blood-Group System↗