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Biomedical subjects

J Clark

Publications and source records attributed to J Clark.

At least 397 records · Page 22Linked to original sources
PubMed1984

Primary adenocarcinoma of the vermiform appendix: report of a series of ten cases, and review of the literature.

Ten cases of primary adenocarcinoma of the vermiform appendix are presented. The condition is rare and usually presents after middle age as acute appendicitis. It is seldom recognized during appendicectomy. The tumours resemble colonic adenocarcinomas but, because of peculiarities in the anatomy of the appendix, there is a tendency to early local spread. Right hemicolectomy performed as soon as the true nature of the lesion is recognized is the treatment of choice and has been shown to improve survival. Even after hemicolectomy the prognosis must be guarded, as local spread of disease may not be controlled in many cases.

Adenocarcinoma↗
PubMed1984

Identification of the human T cell lymphoma virus in B cell lines established from patients with adult T cell leukemia.

Cell lines were established from the peripheral blood of two patients with adult T cell leukemia. In contrast to our previous experience, where all such lines expressed T cell markers, these two cell lines expressed B cell antigens and Ig light chains (kappa on CF-2, lambda on HS). Human T cell lymphoma proviral (HTLV) sequences were demonstrated in both cell lines. Since only a portion of the cells in culture expressed Ig light chains, experiments were carried out to exclude the possibility that the cultures were not a mixture of B and T or non-B cells. Cells that expressed kappa- or lambda-light chains were separated by cell sorting from kappa- or lambda-negative cells and replaced in culture. Light chain negative cells reexpressed light chains after time in culture. After 5-azacytidine treatment of the cell lines, all cells expressed Ig light chains. These studies show that the human retrovirus HTLV, which has been demonstrated to be associated with certain T cell malignancies, can infect B cells or B cell precursors.

Adult↗
PubMed1984

Adult T-cell leukemia/lymphoma in Jamaica and its relationship to human T-cell leukemia/lymphoma virus type I-associated lymphoproliferative disease.

We had shown previously that the prevalence of human T-cell leukemia/lymphoma virus type I (HTLV-I)-antibody positivity is high in Jamaican non-Hodgkin's lymphoma (NHL) patients and that virus-positive patients have the clinical features and poor prognosis of adult T-cell leukemia/lymphoma (ATL). Sixty-two % of 45 NHL patients diagnosed consecutively between 2/1/82 and 1/31/84 and studied prospectively were HTLV-I-antibody positive. Skin involvement (38%), hypercalcemia (44%), and leukemia (40%) were unusually prevalent and there was a strong association (p less than 0.05) with HTLV-I-antibody positivity. Fifty-two % of the patients had bone marrow infiltration, and 74% of these patients were HTLV-I-antibody positive (p = 0.06). Lymphadenopathy (96%), hepatomegaly (60%), and splenomegaly (25%) were detected with about the same frequency as in other series of NHL patients with advanced disease, and 61-88% of these patients were HTLV-I-antibody positive. Patients were classified into those with "typical ATL" (NHL associated with 2 of the 4 features i) hypercalcemia; ii) histologically proven skin infiltration; iii) leukemia; and iv) bone marrow infiltration, providing that the morphology of infiltrating or leukemic cells was characteristic of ATL; those "consistent with ATL" (NHL associated with 1 of these 4 features); and "non-ATL" (NHL without any of these 4 additional features). Thirty-two (71%) of the NHL patients were ATL patients, i.e., had features typical of or consistent with ATL, and 78% of these were HTLV-I-antibody positive. HTLV-I provirus was detected in tumour cells of all HTLV-I-antibody positive patients tested. Three (23%) of the non-ATL patients were HTLV-I-antibody positive. There was no correlation between histopathological features and the clinical classification or HTLV-I-antibody positivity. Median survival of ATL and non-ATL patients was 16 and 53 weeks. Although the disease was usually fulminant, 34% of the ATL patients had a subacute or chronic course. Skin involvement and leukemia were prominent in these patients. Hypercalcemia was the chief prognostic determinant. Median survival of hypercalcemic and normocalcemic ATL patients was 13 and 86 weeks (p less than 0.05). Hypercalcemia caused 10 deaths, infections 12, and death was due to tumour progression in 4 patients. Infections were usually due to pyogenic organisms and only 2 patients had systemic opportunistic infections. Six (27%) of 22 chronic lymphocytic leukemic (CLL) patients were HTLV-I-antibody positive.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

The use of computerized tomography scan in the staging and follow-up study of carcinoma of the rectum.

We have reviewed the CT scans of 30 patients who were evaluated for either primary or recurrent carcinoma of the colon and rectum in the pelvis. The results of our experience have shown that pelvic CT scans can provide accurate information regarding the extramural extension of carcinoma of the rectosigmoid undetected by other means. CT scans can detect significant ureteral pathology as accurately as can IVP and have essentially replaced the IVP in the preoperative evaluation of carcinoma of the rectum. Inflammation of the perirectal musculature, either by the effect of the local tumor or secondary to preoperative radiation, can make it difficult to determine if these structures are invaded by tumor. Tumor involvement, however, can be proved using CT localization and percutaneous fine needle aspiration biopsy techniques. During radiation therapy and chemotherapy, CT scans may also assist in treatment planning and may be the most reliable way of observing the objective response of the recurrent tumor in the pelvis. Finally, in the patient in whom the recurrent tumor does not produce abnormally high levels of CEA, the CT scan may be the only method by which the early and treatable recurrence may be detected. It is, therefore, appropriate to recommend that pelvic CT scan be a routine test for every patient who has had abdominoperineal resection or low anterior resection for carcinoma of the rectum and rectosigmoid.

Anus Neoplasms↗
PubMed1983

Human T-cell leukaemia/lymphoma virus-associated lymphoreticular neoplasia in Jamaica.

19 (34%) of 56 Jamaicans with lympho-proliferative neoplasia had antibody to the human T-cell leukaemia/lymphoma virus (HTLV) in their sera. 17 of those positive had either non-Hodgkin's lymphoma (NHL) or chronic lymphocytic leukaemia. Of 16 consecutive patients presenting with NHL, 11 (69%) were HTLV seropositive. Virus-positive patients with NHL, among whom females were over-represented, had the clinical features and poor survival typical of adult T-cell leukaemia/lymphoma. HTLV-associated leukaemia/lymphoma is a distinct clinicopathological entity, and the high incidence in this series suggests that HTLV is an important cause of lymphoreticular neoplasia in Jamaica.

Adult↗
PubMed1983

Induction of immune responses in vivo with small numbers of veiled (dendritic) cells.

The role of dendritic or veiled cells (VC) from lymph nodes or spleens of rats and mice in initiating immune responses in vivo has been investigated. Host-versus-graft responses were induced by injection of VC from spleens of (C57BL/10 X CBA) F1 mice into the footpads of parental strain (CBA) animals and measured by the increase in the weight of the draining popliteal lymph nodes. The potency of VC to induce the responses was 100-fold greater than that of unseparated spleen cells. The in vivo effect of VC was not limited to this direct allogeneic stimulation because autologous VC could also be used in the induction of an experimental autoimmune disease. In these studies, experimental allergic encephalomyelitis was produced in Lewis rats by injection of guinea pig brain and spinal cord material emulsified in Freund's complete adjuvant. Small numbers of VC from spleens or lymph nodes of rats showing clinical signs of experimental allergic encephalomyelitis induced a mild form of the disease when injected intravenously into normal Lewis rats. Thus, VC carrying antigen, either as an integral part of their surface membrane or acquired during exposure to antigenic substances, appeared to be very potent agents for the induction of immune responses.

Animals↗
PubMed1983

The effect of cycloheximide on the accumulation and stability of functional alpha-mRNA in cells infected with herpes simplex virus.

Cells were infected with herpes simplex virus type 2, HSV-2(G), and incubated in the presence of cycloheximide (CX). When CX was removed and actinomycin D (Act D) added, alpha-polypeptides ICP 0 and ICP 4 were synthesized at low rates. If CX was removed without adding Act D, the rate of production of ICP 4 increased while that of ICP 0 remained constant. In cells treated with azetidine to enhance the production of ICP 4 and 0, accumulation of functional mRNA for ICP 4 (determined indirectly by translation in vivo) was reduced by concentrations of CX between 0.5 and 5.0 micrograms/ml, whereas mRNA for ICP 0 was unaffected by 50 micrograms/ml CX. CX apparently either inhibits the synthesis of ICP 4 mRNA or enhances its inactivation without affecting the production or degradation of ICP 0 mRNA. The accumulation of ICP 4 or ICP 0 mRNA of HSV-1(F) was unaffected by CX. The low levels of ICP 4 and ICP 0 mRNAs of HSV-2(G) that accumulated in the presence of CX disappeared rapidly after adding Act D, in contrast to those of HSV-1(F) which were stable. The ICP 4 mRNA of HSV-2(G) was stable, however, if made without CX or if in mixed infection with HSV-1(F) in the presence of CX. It is suggested that rapid inactivation may account for the low level of accumulation of functional ICP 4 and ICP 0 mRNAs of HSV-2(G) in the presence of CX, and that ICP 4 mRNA is protected by a protein made soon after normal infection. Such a protein may be carried in the virion of HSV-1(F).

Animals↗
PubMed1983

Coagulopathy associated with the use of cephalosporin or moxalactam antibiotics in acute and chronic renal failure.

Nine azotemic patients who developed a coagulopathy associated with the use of either cephalosporin or moxalactam antibiotics are reported. The acute renal failure patients had neoplastic disorders and were considered to be septic at the time that multiple antibiotics were administered. Four of 5 chronic hemo- or peritoneal dialysis patients also received multiple antibiotics. Nevertheless, the coagulopathy seemed to be most closely associated with the administration of the cephalosporin. One patient received moxalactam as part of the combination therapy for diffuse pulmonary infiltration during renal transplant rejection. Bleeding occurred into the gastrointestinal tract in four patients, into the kidney-urinary tract in three patients, into vascular surgical sites in two patients, and one each into the pulmonary-bronchial and cerebral-ventricular systems. Five operations were performed in four patients: a nephrectomy for massive subcapsular hemorrhage with a prothrombin time that exceeded 100 seconds; arteriovenous graft complicated by post-operative bleeding associated with prolongation of the prothrombin time; elective femoral-popliteal bypass complicated by a prolonged prothrombin time, bleeding into the graft site, hypotension, and a subendocardial myocardial infarction; elective cholecystectomy complicated by a two unit bleed associated with a slightly prolonged prothrombin time, followed by elective femoral-popliteal bypass complicated by a fatal intercerebral bleed associated with a more than twice normal prothrombin time. Cephalosporins are most likely associated with Vitamin K deficiency. Moxalactam is more likely to be associated with platelet dysfunction. Monitoring of the prothrombin time for cephalosporins or the bleeding time for moxalactam is the most reliable way to prevent what may be rapid emergence of clinical bleeding in patients with renal failure.

Acute Kidney Injury↗