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Biomedical subjects

M Harris

Publications and source records attributed to M Harris.

At least 649 records · Page 36Linked to original sources

An endemic neurological disorder in tribal Australian aborigines.

Thirteen, and possibly sixteen cases of neurological disorder have been identified in a population of approximately 1100 tribal aborigines living in Groote Eylandt and the adjacent mainland. There were two relatively distinct clinical pictures: one coming on in childhood involved the motor system, the patients often having remarkably lax ligaments; and the other, generally of later onset, comprising cerebellar, upper motor neurone and sometimes supranuclear ophthalmoplegic features. There was some evidence that the two syndromes are varieties of a single condition. No causal factors were identified but there were indications that the disorder might be genetically determined. Attention is drawn to the similarities between this disorder and other ethnic-geographic isolates, particularly the ALS-Parkinsonism-dementia complex of Guam.

Adolescent↗

Vocational training.

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Education, Medical, Graduate↗

Genetic and adaptive differences in the expression of drug resistance in hybrid cells.

Hybrids between Chinese hamster cells were isolated and maintained in media that were selective or nonselective for markers present in the parent cells (HGPRT and TK deficiencies, respectively). Segregation frequencies for resistance to azaguanine (AZG), thioguanine (THG), or bromodeoxyuridine (BrdU) could be enhanced for some groups of hybrids if the stock cells were maintained under nonselective conditions rather than in HAT medium. In these populations the expression of resistance was dominant or codominant even though marker patterns were recessive for the same cells in HAT. Clonal analysis showed that enhancement took place by adaptive shifts rather than by variation and selection. Segregation frequencies in hybrids were also found to differ significantly between clones isolated by replicate fusions of any two parental cell types. The basis for this heterogeneity is unknown and deserves further study.

Animals↗

Atypical odontalgia.

Forty-four cases of odontalgia are described which are considered to be a painful migraine-like disturbance of the blood vessels of the dental pulp and periodontal membrane. The condition appears to be a manifestation of depression and other personality disorders and responds well to antidepressant drug therapy (75 per cent of the patients). The recognition and proper management of this atypical ondontalgia is of crucial importance in preventing unnecessary surgery.

Adult↗

Myotonia dystrophica: unusual features in a Labrador family.

A large family with myotonia dystrophica has been recognized in an isolated area of Labrador. The complete family tree showed 29 of 108 members to be affected, including an infant with the congenital form of the disease. The propositus presented with epiphora and reduced frequency of blinking, with incomplete closure--features that have not previously been stressed. Ten of the younger affected persons had no lens opacities, although most had systemic muscle signs. Slit-lamp examination was therefore not a valuable method of early detection of the disease in the family. Many of the women affected by myotonia dystrophica had obstetric complications, particularly hydramnios, premature onset of labour, necessity for cesarean section, postpartum hemorrhage and neonatal death. Hydramnios was associated in each instances with perinatal death. The fetus in each case of hydramnios may have had the gene for myotonia dystrophica. Immunoglobulin A concentrations were reduced significantly in 27 affected persons in comparison with 77 unaffected family members. There were no such differences for the other immunoglobulin classes.

Adolescent↗

Epidermotropically metastatic malignant melanoma. Differentiating malignant melanoma metastatic to the epidermis from malignant melanoma primary in the epidermis.

In four instances, metastases to epidermis from primary cutaneous malignant melanomas at different sites showed histological features similar to those of cutaneous malignant melanoma primary in the epidermis. In these metastases, atypical melanocytes were present within the epidermis and in the upper part of the dermis much as in primary cutaneous malignant melanoma. Therefore, the presence of atypical melanocytes within the epidermis is not in itself an absolute criterion of malignant melanoma primary in skin. Nor does that finding absolutely deny malignant melanoma metastastic to the skin. Features that may enable histologic differentiation of epidermotropically metastatic malignant melanoma from primary cutaneous malignant melanoma are emphasized.

Adult↗