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Biomedical subjects

M Harris

Publications and source records attributed to M Harris.

At least 631 records · Page 35Linked to original sources
PubMed1982

Problems encountered at work by people with severe acquired hearing loss.

A structured questionnaire concerning problems encountered at work was administered to 88 adults of employment age suffering from acquired sensorineural hearing loss (60 dB +). While respondents were not likely to be out of work by virtue of their hearing loss, they found it difficult to cope at work for a variety of reasons. Information from a subsequent open-ended interview threw some light on the validity of the questionnaire and in particular illustrated the need to combine quantitative and qualitative methods of data collection.

Adult↗
PubMed1982

Treatment of recurrent and persistent germ cell tumors with cisplatin, vinblastine, and bleomycin.

Four patients were treated with vinblastine, cisplatin, and bleomycin for recurrent or persistent germ cell tumors. In all patients a clinical response was achieved. In 2 patients complete response was attained and they are free of disease following second-look laparotomy. One had a mixed germ cell tumor that persisted as dysgerminoma following primary chemotherapy. The other was a true hermaphrodite with pure dysgerminoma. In patients with endodermal sinus tumor transient response was achieved, but the tumors recurred and the patients died within 6 months.

Adolescent↗
PubMed1982

Decreasing B-wave amplitude noted in erg in one type of retinitis pigmentosa.

Electroretinographic studies have been helpful in differentiating human forms of retinitis pigmentosa inherited by different patterns. The prognosis appears to be correlated with the mode of inheritance. The recessively inherited form along with the x-linked and dominantly inherited with reduced penetrance type of inheritance are associated with more severe forms of the disease than is the dominantly inherited with complete penetrance. The underlying biochemical defects have not been identified. Human pathological specimens early in the disease have been almost nonexistent. Animal models have been identified but correlation with human disease has been markedly limited [1]. Electrophysiology and recent technology offer some prospect for differentiating responsible abnormalities and offer a noninvasive evaluation of the disease process and treatment. Three cases of dominantly inherited retinitis pigmentosa with complete penetrance are presented. These show a decreasing B-wave amplitude on successive photopic evaluations using fast random stimuli.

Adolescent↗
PubMed1981

Electrophysiological identification of neurones of paraventricular nucleus sending axons to both the neurohypophysis and the medulla in the rat.

Neurons within the hypothalamic paraventricular nuclei (PVN) have been antidromically invaded following electrical stimulation within the pons and medulla of rats. These neurones are dispersed throughout the PVN and are often found near neurones antidromically invaded only from the pituitary salk. In addition, a small number of PVN neurones have been found that were antidromically invaded from both the caudal brain and the pituitary stalk. The functional significance of these neurons is unknown at the moment, but the possibility of feedback control of the neurohypophysis must be considered.

Animals↗
PubMed1981

The catecholaminergic nerve supply to small intracerebral vessels following a cold injury to the mouse cortex.

A cold lesion was produced in the mouse parietal cortex. The damaged area was examined for alterations in the catecholamine fibres either by fluorescence microscopy or by electron microscopy. Within 24 h of injury many damaged catecholaminergic nerves were observed in close association with small intracerebral blood vessels. This relationship between nerves and blood vessels was not apparent in the control cortex. In the electron microscope, swollen non-myelinated axons containing an accumulation of dense-cored vesicles were observed close to the vessel wall but separated from it by astrocytic process. Six days after injury regenerating catecholaminergic nerve fibres were found close to immature capillaries. Axonal-like profiles containing dense-cored vesicles were observed adjacent to the endothelial call basement membrane. The number of regenerating nerves declined with time and the only fluorescent catecholaminergic nerves that remained 12 weeks after injury were in an area known to be rich in capillaries.

Animals↗
PubMed1981

Signet ring cell lymphoma: a rare variant of follicular lymphoma.

A case of signet ring cell lymphoma, the eighth in published reports is recorded. This rare tumour is a variant of follicular lymphoma which may be mistaken for metastatic carcinoma. The case has been studied by light microscopy, immunohistochemistry and electron microscopy and confirms that this sub-group has rather uniform characteristics. Observations on the possible origins of the vacuoles are presented.

Humans↗
PubMed1981

Use of environmental aids by adults with severe sensorineural hearing loss-an exploratory study.

In the course of a study to investigate the effect of severe hearing loss on family life it became apparent that many of the difficulties encountered could have been alleviated by the acquisition or better use of appropriate environmental aids. In some cases the problems were practical and in others social or psychological in nature. This paper consists of a detailed examination of such problems and discusses ways in which environmental aids could improve the quality of life for hearing impaired persons and their families.

Adult↗
PubMed1981

Care of mildly ill children enrolled in day-care centers: management by parents and by trained home workers.

Because child day-care regulations exclude ill children, parents are frequently faced with problems in finding an alternative care arrangement. This pilot study compares home care of mildly ill children by parents (46 preschool children) with care by trained home workers (23 preschool children) during 20 weeks in 1977. Episodes of illness in children cared for by trained home workers showed a slightly shorter duration (median 3.0 days, range 2 to 11 days versus median 5.2 days, range 2 to 14 days) and a less severe course (fewer and milder signs of illness) when compared with episodes of illness in children cared for by parents. Other selected activities involved in the management of the mildly ill children were comparable. Although larger studies are needed, it appears that if parents desire an alternative care arrangement for their children during mild illness, care by a trained home worker may be convenient and safe.

Child↗
PubMed1981

Subacute cholinergic dysautonomia in childhood.

Clinical features of a 10-year-old boy who presented with manifestations of subacute autonomic neuropathy are described. The pupillary abnormalities, reduced tear, sweat and saliva production, and visceral dysfunction suggest a lesion restricted to cholinergic postganglionic endings of the autonomic nervous system. There was no evidence of dysfunction at the neuromuscular junction or elsewhere in the nervous system. The cause of the cholinergic dysautonomia has not been found. Clostridium botulinum infection could not be verified, and although a variety of Clostridium species were isolated from the faeces they could not be shown to produce a neurotoxin.

Autonomic Fibers, Postganglionic↗
PubMed1980

The structure of the human thyroid in relation to ageing and focal thyroiditis.

Quantitative studies of non-nodular thyroid glands without focal thyroiditis obtained from consecutive autopsies on women aged over 20 yr showed a decrease in colloid content and an increase in stromal tissues with advancing age. When focal lymphocytic thyroiditis was present these changes were increased. This observation supports the theory that low-grade auto-immune processes can mimic or accelerate the ageing process but does not indicate that they initiate it.

Adult↗
PubMed1980

Pyruvate blocks expression of sensitivity to antimycin A and chloramphenicol.

Selectivity in Chinese hamster cells with antimycin A and chloramphenicol depends on a metabolic balance which can be modulated by varying the level of exogenous pyruvate. The effects of both inhibitors are most clearly seen in pyruvate-free nutrients. Addition of 1 mM pyruvate in plating assays shifts dose-response curves for antimycin A or chloramphenicol to higher concentration levels and reduces the differential in response between sensitive and resistant cells. In mass populations, growth inhibition by antimycin A is reduced by adding pyruvate, and growth curves for sensitive and resistant cells tend to converge. These observations show that responses to antimitochondrial drugs can be conditioned by extrinsic factors and indicate the need for further definition of selective systems.

Animals↗
PubMed1980

Phenotypic evolution of cells resistant to bromodeoxyuridine.

Variants resistant to bromodeoxyuridine (BrdUrd) and deficient in thymidine kinase (ATP:thymidine 5'-phosphotransferase; EC 2.7.1.21) have been obtained from V79 Chinese hamster cells by a combination of spontaneous and drug-induced change. Initial mutations take place in wild-type populations as a facilitating step to give partially resistant clones that can be isolated by one-step selection in BrdUrd. When these tolerant populations are maintained for extended periods in BrdUrd-containing medium, a gradual phenotypic transition occurs in which BrdUrd appears to act as an inductive as well as selective agent. Thymidine kinase activity declines logarithmically over an interval of 8-10 weeks as the growth rate rises and the cells become completely resistant to BrdUrd. Relative plating efficiency in hypoxanthine/aminopterin/thymidine medium also decreases, but the decrease is not coordinate with shifts in thymidine kinase activity. The potential for colony formation in hypoxanthine/aminopterin/thymidine continues to decrease exponentially for at least 18 weeks after thymidine kinase deficiency and complete resistance to BrdUrd have been established. These phenotypic modifications are continuous or multistep in character; by clonal analysis they are found to occur in most, if not all, cells maintained in the presence of BrdUrd. Populations in transition thus come to be complex mosaics of different phenotypes that are comparatively stable if isolated in drug-free medium. The progressive evolution of cells resistant to BrdUrd will require new models for an underlying explanation.

Animals↗
PubMed1980

Stable heat-resistant variants in populations of Chinese hamster cells.

Sublines with increased survival at elevated temperatures were obtained by repeated exposure of V79 Chinese hamster lung cells to 44.5 degrees C followed by regrowth of survivors to mass populations at 37 degrees C. After three cycles, the time at 44.5 degrees C required to reduce cell survival to 37% (D0 value) increased from 4.6 to 26.3 minutes. Clonal isolates retained their resistance to thermal stress for at least 3 months in culture at 37 degrees C and showed distinctive differences from precursor cells in growth rate and colonial morphology. These differences disappeared in hybrids constructed between resistant and sensitive cells. In assays of 44.5 degrees C, hybrid survival was only slightly increased over levels obtained with sensitive cells. Heat resistance and associated marker characteristics thus appear to be recessive or weakly codominant. Cytohybrids were also constructed by fusing cytoplasts from sensitive cells to nucleated heat-resistant cells. No cytoplasmic transfer of marker characteristics was detected in these combinations, which suggests that controls for heat resistance are nuclear in origin.

Animals↗
PubMed1980

The ultrastructure of benign and malignant fibrous histiocytomas.

Five benign histiocytomas of varying pattern and three malignant fibrous histiocytomas have been studied ultrastructurally. An essentially biphasic pattern of histiocytes and fibroblasts was present. In addition fibrohistiocytes, myofibroblasts and undifferentiated cells were present in some of the tumours. The histogenesis of this group of tumours is discussed. The value of electron microscopy in establishing the diagnosis in difficult cases is emphasized, but it is not considered useful in distinguishing benign from malignant cases.

Fibroblasts↗