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Biomedical subjects

D H Wright

Publications and source records attributed to D H Wright.

At least 163 records · Page 9Linked to original sources
PubMed1979

Electron microscopy of cerebral malaria in golden hamsters (Mesocricetus auratus) infected with Plasmodium berghei.

Transmission and scanning electron microscopy of hamster cerebral malaria show that haemorrhages occur following vessel necrosis in animals with low parasitaemias. There is no concurrent thrombosis nor packing of capillaries with parasitised erythrocytes. Small vessels contain numerous monocytes which have phagocytosed erythrocytes and smaller particles of similar electron density. The monocytes attach to and migrate through the endothelium but then remain in close proximity to the vessels. Irregular dense deposits are present in the basement membrane of some animals 14 days after infection. These may be immune complexes. The pathogenesis of cerebral malaria is discussed in relation to these findings.

Animals↗
PubMed1979

Anomolous staining patterns in immunohistologic studies of malignant lymphoma.

A number of immunoperoxidase studies of malignant lymphomas have reported polytypic light chain staining of neoplastic cells, thus bringing into question the concept that the monoclonality of B cell lymphomas is reflected in their synthesis of monotypic light chain. In this study of a large number of Ig positive lymphomas, staining for a wide variety of antigens has identified clear differences between monotypic Ig synthesizing cells and cells staining polytypically which appear to be taking up Ig from the environment. Attention to the nature of Ig staining and staining for J chain were the two most useful criteria in differentiating Ig synthesis from uptake. The results confirm that malignant B cell lymphomas synthesise monotypic Ig.

Humans↗
PubMed1979

An experimental study of the pathology and ecology of Yersinia enterocolitica infection in mice.

Four experiments are described in which laboratory mice were infected with Y. enterocolitica using an American serotype 0:8 (WA) and two European strains, serotypes 0:3 and 0:9. The pathogenicity and histopathological responses of strain WA (0:8) were determined in the Porton white outbred mouse by three route of inoculation. The LD50 after infection by the intraperitoneal route was 8.8 x 10(1) organisms, which is similar to results obtained by previous workers using disease-free and hybrid mouse strains. European strains 0:3 and 0:9 were shown to infect the Porton white outbred mice when injected intraperitoneally but no deaths occurred. Chronic faecal excretion was demonstrated up to 135 days. Specific antibodies were detected in the 0:3 and 0:9 infected mice and the immune response was further assessed by challenging the excreter mice with 50LD50S of the virulent WA strain. A significant degree of protection occurred in mice previously injected with 10(7) organisms of the avirulent strains. No evidence of phenotypic variation, as measured by 40 markers, was detected in 67 isolates of Y. enterocolitica recovered during the course of the four experiments. These results suggest that laboratory rodents could be a useful model for studying the infection produced by virulent and avirulent strains, and since it has been clearly established that a wide range of serotypes and non-typeable strains may be isolated from wild rodents, our findings could be extrapolated to the wildlife situation. Further work on the laboratory model could give a more detailed insight into the mechanism and extent to which rodents act as reservoirs of Y. enterocolitica.

Animals↗
PubMed1978

Intestinal lymphoma associated with malabsorption.

Of 18 patients with small-intestinal lymphoma associated with villous atrophy and crypt hyperplasia of uninvolved mucosa, most presented with acute obstruction or perforation preceded by abdominal pain and weight-loss. Malabsorption, thought to be adult coeliac disease, preceded the diagnosis of lymphoma in 5 cases. The lymphomas were composed of malignant histiocytes and were classified on morphological grounds as malignant histiocytosis. Of particular interest was the finding by immunohistochemical techniques of all major immunoglobulin classes within malignant cells of single tumors. Characterisation of this group of lymphomas as a specific entity should help in the further understanding of the relationship of malabsorption and lymphoma and in the rationalisation of treatment.

Adult↗
PubMed1978

Malignant histiocytosis of the intestine. Its relationship to malabsorption and ulcerative jejunitis.

The clinical and histopathologic features in seven patients with intestinal lymphoma are reported. Three of these presented with ulcerative jejunitis and four with overt lymphomas. A short history of abdominal pain with weight loss followed by intestinal obstruction, hemorrhage, or perforation characterized all the patients except one in whom a nine year history of malabsorption preceded the acute phase of the disease. Malabsorption was demonstrated in four of the patients, and all showed villous atrophy with crypt hyperplasia of the jejunum remote from areas of ulceration or frank lymphoma. The malignant lymphoma cells showed varying degrees of pleomorphism and exhibited phagocytosis of platelets, red cells, and cell debris. The accompanying infiltrate of inflammatory cells often overshadowed the neoplastic histiocytes, and in those cases showing little pleomorphism these cells could be easily overlooked. In the intestine the tumor cells were usually present as a diffuse infiltrate in the lamina propria or within the bases of ulcers and in five of seven cases did not give rise to macroscopic tumor masses. In all patients dissemination of tumor cells to the lymph nodes, liver, spleen, and bone marrow was evident, the infiltrate in all these organs resembling that seen in malignant histiocytosis. The morphology of the tumor cells, their phagocytic nature, the diffuse character of the tumor infiltrate, and the pattern of dissemination suggest that this lesion should be designated malignant histiocytosis of the intestine rather than histiocytic lymphoma (reticulum cell sarcoma). It is suggested that the tumor may arise from cells of monocyte-histiocyte lineage normally present in the lamina propria of the gut and that a prolonged cryptic phase accompanied, and often overshadowed, by an inflammatory reaction may give rise to malabsorption and ulcerative jejunitis before overt lymphoma is manifest.

Aged↗
PubMed1978

Immunopathology of angioimmunoblastic lymphadenopathy.

Eight patients with angioimmunoblastic lymphadenopathy have been studied by a variety of immunological and pathological techniques. They exhibited a spectrum of immunological reactivities that, in this small series, could be roughly correlated with survival. Those patients with relative B-cell predominance as shown by cell marker studies, histologically showed large numbers of plasma cells, and this pattern was associated in 3 of our patients with a survival of 3 years or more. T-cell predominance or both B- and T-cell depletion was associated histologically with large numbers of blast cells and eosinophils, but with few plasma cells. These patients responded poorly to therapy and had short survival times. One patient with B-cell predominance subsequently died of a histiocytic lymphoma.

Adult↗
PubMed1978

Absence of IgG lymphocytotoxins in untreated Hodgkin's disease (HD) patients.

Six of twenty-three sera (26%) from patients with Hodgkin's disease (HD) contained IgG antibody with an affinity for human lymphocytes and lymphoblastoid cell lines. All sera were negative for complement-dependent and antibody-mediated cell cytotoxicity against human lymphoid cells irrespective of their binding capacity. It is suggested that the antilymphocyte antibodies seen in HD are not of pathogenic significance but are a non-specific consequence of B-cell stimulation.

Antibody Affinity↗
PubMed1977

Lymphocyte markers in non-Hodgkin's lymphomas.

The lymphocyte marker pattern of non-Hodgkin's lymphoma cells was related to current concepts of lymphoma classification. In a series of 28 lymphomas lymphocyte markers indicated that 2 were of histiocytic origin, 2 were unclassifiable, none were derived from T cells and the remainder were B-cell neoplasms. The immunoglobulin heavy chain associated with the B-cell tumours was gamma in one case, alpha in one case but was mu in the majority of cases, reflecting the predominance of this heavy chain, together with delta chains, on normal lymph node lymphocytes in man. delta chains accompanied mu chains on the tumour cells in 6/17 lymphomas in which anti-delta staining was performed. delta chains were not found on any lymphomas other than well differentiated diffuse lymphocytic types. There was evidence of a reduction in surface immunoglobulin, Fcgamma and C3 receptors on undifferentiated lymphoma cells. T lymphocytes of normal morphology were present in all lymphomas except one, and were more numerous in follicular lymphomas than in diffuse tumours.

B-Lymphocytes↗
PubMed1976

Tumorigenicity of Epstein-Barr virus (EBV)-transformed lymphoid line cells in autologous squirrel monkeys.

Eight squirrel monkeys (Saimiri sciureus) challenged with EBV or EBV-transformed SLCL were naturally or experimentally infected with Plasmodium knowlesi or Pl. brasilianum. Most of the animals had been splenectomized and unilaterally nephrectomized. Three of these monkeys received one dose of 6 to 12 X 10(8) autologous SLCL. These lines were derived from saimiri lymphoid cells permanently transformed by B-EBV in vitro. All three animals developed multiple undifferentiated malignant lymphomas and died 8 to 10 days post inoculation. Necropsy tumor specimens were EBNA-positive and contained 7 to 21 EBV genome equivalents per cell. EBNA- and EA-positive SLCL were established in vitro from four tumor explants of two monkeys. These results demonstrate that in vitro EBV-transformed SLCL are able to cause tumor formation in autologous squirrel monkeys. Five monkeys received high transforming doses of B-EBV or S-EBV, derived from one of the tumorigenic SLCL. None of the animals developed any sign of tumor formation during an observation period of up to 130 days. Three of these monkeys showed no detectable EBV-related seroconversion while the sera of two monkeys had become anti-EBNA-positive when tested at days 28 and 130 respectively post inoculation. Two additional monkeys received neither EBV nor SLCL. They showed no clinical evidence of tumor development or spontaneous seroconversion over a period of more than 1 year.

Animals↗
PubMed1976

A new technique for radiotherapy planning using quadratic programming.

Previous attempts at optimization of radiotherapy planning are described and criticized, and consideration of these attempts has resulted in the development of a new technique using quadratic programming. Uniformity of tumour dose is selected as the most important feature of any plan, and this is achieved by minimizing the variance of the dose to preselected points within the tumour. The dose to vulnerable regions can be constrained not to exceed a given percentage of the mean tumour dose. Optimization of field weight and field type is possible. The operation of the system is described and some typical results are given.

Humans↗
PubMed1976

T and B lymphocytes and Reed-Sternberg cells in Hodgkin's disease lymph nodes and spleens.

Lymphoid cells from twenty-four untreated Hodgkin's disease biopsies were examined for spontaneous sheep erythrocyte and sensitized ox erythrocyte rosette formation for the identification of T cell and cells with Fc and C3 receptors and surface immunoglobulin. Compared with normal tissues mean T-lymphocytes values were elevated in both involved lymph nodes and uninvolved spleens from Hodgkin's patients. Lymphocytes bearing C3 receptors were correspondingly reduced in these tissues. Involved spleen T-cell values fell within the normal range. In normal tissues the sum of lymphocytes with surface immunoglobulin and sheep erythrocyte receptors fell in the range 89-108%. In six biopsies of Hodgkin's tissue the sum was outside the normal range (121-142%). This observation is compatible with surface immunoglobulin-coated T cells. Surface marker characteristics and intracellular immunoglobulin studies of small lymphocytes, lymphoblasts and Hodgkin's cells suggested that the neoplastic cells were of B lymphocyte origin.

Adolescent↗
PubMed1975

A set of fortran subroutines for optimizing radiotherapy plans.

Quadratic Programming techniques have been applied to the optimization of radiation field weighting in Radiotherapy planning. Wedge selection has also been included by means of an exhaustive search. The radiation dose at any point in the patient may be constrained to be less than a stated percentage of the tumour dose. The routines have been successfully interfaced into a small computer interactive planning system, but they could represent an even more powerful tool in batch and time sharing systems. Minimum operator intervention is required in their use.

Computers↗