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Biomedical subjects

D M MacDonald

Publications and source records attributed to D M MacDonald.

215 records · Page 12Linked to original sources
PubMed1978

Ultrastructural demonstration of T cells in cutaneous tissue sections using specific anti-human T cell antiserum.

The presence of T lymphocytes in the situ in cutaneous infiltrates of contact dermatitis and lichen planus has been demonstrated by an immunoelectronmicroscope technique. A specific anti-human T cell antiserum labelled with peroxidase-conjugated anti-immunoglobulin serum was used to reveal the specific human T lymphocyte antigen (HTLA) which was visualized ultrastructurally. This technique shows that labelling is limited to the surface membrane and allows study of the in situ interrelationship of T cells.

Antigens, Surface↗
PubMed1978

[Repigmentation of vitiligo induced by oral photochemotherapy. Histoenzymological and ultrastructural study (author's transl)].

The authors studied by histoenzymology and electron microscopy, repigmentation induced by oral photochemotherapy (8-MOP-UVA) in 4 patients with vitiligo. The presence of hypertrophic melanocytes was demonstrated in the middle and deep portions of certain centre of islands of repigmentation. Melanocytes comparable to these were also observed in the epidermis of the peripheral collerette in the island of repigmentation. No melanocytic mitosis could be seen in the repigmenting epidermis. Ultrastructural study showed that the melanocytes of the repigmented zones were hyperactive. The melanosomes which they synthesize have a slightly larger size than the melanosomes of the neighbouring healthy skin. Their mode of intrakeratinocyte grouping was not altered. These results suggest that the origin of the melanocytes which repigment the vitiliginous epidermis under the influence of PUVA derives probably from a melanocytic reservoir localized in the hair follicle.

Humans↗
PubMed1977

Skin cancer.

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Humans↗
PubMed1977

Immunofluorescence studies in primary localized cutaneous amyloidosis.

Immunofluorescence studies were carried out on 47 patients with primary localized cutaneous amyloidosis. The majority had the macular, maculopapular or papular forms of lichen amyloidosus, although 3 patients had the nodular type. All biopsies fluoresced positively for immunoglobulins or complement, particularly IgM and C3. Staining for kappa and lambda light chains was positive. The consistent immunofluorescent patterns observed were similar in some respects to lichen planus, suggesting that colloid bodies and amyloid may share similar properties in acting as a filamentous sponge on to which immunoglobulins and complement are absorbed. The pathogenesis of lichen amyloidosus is compared with that of lichen planus.

Amyloidosis↗
PubMed1977

Juvenile elastoma and osteopoikilosis (the Buschke--Ollendorff syndrome).

Sixteen patients from seven different families with the Buschke-Ollendorff syndrome have been studied. Osteopoikilosis was found in two-thirds of the patients radiologically examined and all but two had skin involvement. The predominant clinical pattern consisted of grouped skin coloured papules and discs that were distributed asymmetrically and which usually had presented at an early age. The skin lesions showed the characteristic histological changes of juvenile elastoma which, it is suggested, is the specific dermatological abnormality of the Buschke-Ollendorff syndrome.

Adult↗
PubMed1977

Pacinian neurofibroma.

At rare intervals in the literature, reports have appeared of a skin tumour containing structures resembling Pacinian corpuscles. Four such tumours collected over the course of 20 years are described and the literature reviewed.

Adolescent↗
PubMed1976

Cutaneous ectopic schistosomiasis.

Two cases of cutaneous schistosomiasis due to ectopic ova have recently been seen. Both patients presented with abdominal papular lesions, which were found on biopsy to contain schistosoma ova. To reach these abdominal sites mature worms probably migrate from the portal circulation to the paraumbilical veins, where they anastomose with veins of the caval system.

Adult↗
PubMed1975

Studies concerning the mechanism of suppression of renin secretion by clonidine.

Two series of experiments were performed in anesthetized dogs to test the hypothesis that the suppression of renin secretion by clonidine results from a centrally mediated decrease in the activity in the renal sympathetic nerves. In the first series, clonidine (1 mug/kg) was administered directly into the third ventricle of a group of dogs in which renal perfusion pressure was controlled by adjusting an aortic clamp. In these animals, clonidine produced hypotension and bradycardia and suppressed plasma renin activity to 39 percent of the control value. These changes in blood pressure and plasma renin activity were closely correlated. Intraventricular clonidine produced similar alterations in blood pressure and heart rate in another group of dogs in which renal perfusion pressure was not controlled, but failed to suppress plasma renin activity. In the second series of experiments, clonidine was administered intravenously in a dose of 30 mug/kg. Intravenous clonidine produced a transient hypertension followed by hypotension, decreased heart rate and suppressed plasma renin activity to 49 percent of the control value. Renal denervation reduced renin secretion and prevented the suppression of renin secretion produced by intravenous clonidine. Thus, these data are consistent with the hypothesis that the suppression of renin secretion by clonidine results from a centrally mediated decrease in renal sympathetic neural tone. This suppression may be overcome by large falls in renal perfusion pressure.

Animals↗
PubMed1975

Acanthoma fissuratum--spectacle frame acanthoma.

The development of a cutaneous nodule at the site of friction of spectacles has been discussed by several authors. In all but one case the lesion occurred behind the ears. The only previous report of this acquired tumour occurring on the nose is that of Farrell & Wilson (4). It is suggested that this problem is relatively common and most frequently presents when mistaken for basal cell epithelioma or when identified in medical personnel. A further six cases of this neglected tumour occurring on the nose are described.

Adult↗