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Biomedical subjects

R J Collins

Publications and source records attributed to R J Collins.

At least 73 records · Page 4Linked to original sources
PubMed1989

Colorectal carcinoma in Hong Kong Chinese. A pathological survey of 1,117 cases, 1972-1981.

Hong Kong Chinese, when compared with the world population, have an intermediate incidence rate for colorectal carcinoma. The purpose of this retrospective analysis of a large number of colorectal carcinomas (1,117 cases) was to explore possible differences between this series and others, and to re-examine the divergent features reported in a smaller series. The present study revealed a distribution by age, sex, site and Dukes' stage, as well as histopathological features, which were analogous to those reported from other countries. Thus, while the incidence is lower in this group, the other manifestations of the disease are very similar to those seen elsewhere. The implication is that, apart from varying incidence, there is a global similarity among colorectal tumours.

Adult↗
PubMed1989

Pleomorphic adenoma of the external auditory canal. An immunohistochemical and ultrastructural study.

Primary tumors arising from the glandular structures of the external auditory canal (EAC) are rare, with the majority arising from the ceruminous glands. The histochemical, immunohistochemical, and electron microscopic features of a pleomorphic adenoma of the EAC are presented; this is the seventh case reported. These studies confirm the key role of the myoepithelial cell in this tumor and include a correlation with pleomorphic adenomas in other sites.

Actin Cytoskeleton↗
PubMed1989

Detection of antibodies to extractable nuclear antigens using calf thymus and rabbit thymus. A comparative study of 1000 consecutive anti-nuclear antibody positive patients.

A comparison between calf thymus extract and rabbit thymus extract to determine their suitability for clinical laboratories in detecting antibodies to extractable nuclear antigens (ENA) was undertaken. Calf thymus extract (CTE) detected 90% more ENA positive patients and 155% more lines than rabbit thymus extract (RTE). In contrast to RTE, CTE resolved Sm and RNP into two distinct lines, had superior stability at -80 degrees C and produced greater clarity of definition of precipitin lines.

Animals↗
PubMed1989

Cell death by apoptosis in acute leukaemia.

We have previously demonstrated that when freshly isolated childhood T-cell acute lymphoblastic leukaemia cells are incubated in growth medium after isolation from blood, chromatin is rapidly cleaved into nucleosomal sized fragments that are multiples of 200 bp. The fragmentation is similar to that observed in other types of cells undergoing apoptosis or programmed cell death. In this study we describe a more comprehensive approach to the study of DNA fragmentation in leukaemia. Fragmentation was observed in freshly isolated cells from patients with T-cell acute lymphoblastic leukaemia and in one with common acute lymphoblastic leukaemia. Frozen samples of T-cell acute lymphoblastic leukaemia, common acute lymphoblastic leukaemia, and acute myeloid leukaemia cells also showed fragmentation of DNA. However, no fragmentation was evident in normal leukocytes treated under the same conditions. Ultrastructural studies on the isolated leukaemia cells demonstrate that the chromatin cleavage observed biochemically is associated with morphological changes characteristic of apoptosis.

Cell Survival↗
PubMed1989

The value of tumor markers in a mixed tumor, mucinous and neuroendocrine carcinoma of the ovary.

Serum CA125 is frequently used to monitor the treatment response and to detect early recurrence during the follow-up of patients who have epithelial ovarian tumors. In this report, the level of serum CA125 and urinary 5-hydroxyindole acetic acid of a patient with a carcinoid tumor which occurred in association with a mucinous adenocarcinoma of the ovary is described. The level of serum CA125 decreased despite the presence of a clinically progressive tumor. There was a rise of the 5-hydroxyindole acetic acid level 16 weeks before pelvic recurrence was detected clinically. This indicates that it was the neuroendocrine component, and not the mucinous component of the tumor, that was not responsive to the chemotherapy. The problem of using tumor markers to monitor patients with mixed tumors is discussed.

Adenocarcinoma, Mucinous↗
PubMed1989

Adenocarcinoma of the uterine cervix with beta-hCG production: a case report and review of the literature.

The production of unexpected cell products, including the placental protein human chorionic gonadotrophin (hCG), has been reported in a variety of tumors at different anatomical sites. Some of the reported tumors have also expressed morphological features suggesting choriocarcinoma. Such is the case in this tumor of the uterine cervix which has a major component of anaplastic tumour with beta-hCG production confirmed both by positive staining using immunoperoxidase techniques and by pre- and postoperative serum assays for beta-hCG. The differing immunohistochemical features seen in the two components of the tumor are reported. The relationship of the anaplastic component to the adjacent mucinous adenocarcinoma in the present case, and to similar cases at other sites from the literature, is discussed.

Adenocarcinoma↗
PubMed1989

Origin of rare Ha-ras alleles: relationship of VTR length to a 5' polymorphic Xho I site.

Amongst the four common Ha-ras alleles in both controls and cancer patients, we detected the presence of a polymorphic Xho I site associated specifically with the 6.6 and 7.7 kb Bam HI fragments but absent from the 7.1 and 8.2 kb alleles, as recently reported by others. We have extended this study and report here, the consistent appearance of this Xho I site in unusual alleles close in size to the two common alleles of 6.6 and 7.7 kb, in control lymphoblastoid DNA samples in a variety of tumor DNAs. Unusual alleles grouped around the 7.1 and 8.2 kb common alleles on the other hand, did not possess the Xho I site. The consistent presence of the Xho I site polymorphism, in the unusual Ha-ras alleles surrounding the 6.6 and 7.7 kb common alleles and its absence in alleles around the 7.1 and 8.2 kb common alleles, suggests that the unusual ones are derived from the corresponding common alleles to which they are closest in size.

Alleles↗
PubMed1989

Spontaneous programmed death (apoptosis) of B-chronic lymphocytic leukaemia cells following their culture in vitro.

When B-chronic lymphocytic leukaemia (B-CLL) cells derived from peripheral blood were cultured in vitro, a substantial proportion of them spontaneously died by apoptosis. This type of cell death is morphologically and biochemically distinct from necrosis and has previously been found to occur under physiologic and certain pathologic conditions where cell deletion appears controlled and biologically meaningful. By 30 h of culture, approximately 20% of the unfractionated B-CLL cells were affected. There was no significant difference in the incidence of apoptosis in T-cell depleted and undepleted cultures or when either autologous or normal human serum was used. Furthermore, seeding densities of 2 x 10(6) and 5 x 10(5) cells/ml resulted in a similar incidence of apoptosis, indicating that cell density was unlikely to be a contributing factor in producing the death. The finding that B-CLL cells spontaneously die in vitro has at least two important implications. Firstly, previous work relating to some of the functions of B-CLL cells and their interactions with T cells may require re-evaluation. Secondly, an understanding of the mechanisms involved in the induction of apoptosis in this disease may have therapeutic consequences.

Blood Cell Count↗
PubMed1989

Cell suspensions from collagenase digestion of bone marrow trephine biopsy specimens.

A technique for the extraction of cells from bone marrow trephine core biopsy specimens using collagenase digestion was assessed in 39 cases (33 diagnostic and six normal). Diagnostically useful numbers of cells were extracted from all marrows. Morphological assessment of cytocentrifuge preparations of these cells gave a correct diagnosis in 23 (60%) of cases compared with 27 (70%) for the corresponding aspirated marrow smears. Phenotypic analysis using flow cytometry showed persistence of a range of surface membrane antigens following collagenase digestion. Increased autofluorescence was a problem in some cases. Cytochemistry, bone marrow culture, and cytogenetic analysis could also be carried out on these cells. It is concluded that this technique has useful diagnostic applications in cases of dry taps.

Adult↗
PubMed1989

Niemann-Pick disease in the Chinese. A report of four cases in three Chinese families.

We report the first four documented cases of childhood Niemann-Pick disease in Chinese. The clinical histories and biochemical, histopathological and ultrastructural findings are given. The four children born to consanguineous parents were from three families. Three of the four cases have features of Type A disease while the younger of the affected sisters, who had over 20% residual sphingomyelinase activity, was more typical of Type B disease. Post-mortem cultured fibroblasts, when compared to control fibroblasts, revealed early features of the disease at the ultrastructural level.

Cerebral Cortex↗
PubMed1988

A histopathological study of pulmonary infection of mice with Mycobacterium lepraemurium.

Intranasal instillation of Mycobacterium lepraemurium (MLM) into mice produced pulmonary infection. MLM multiplied rapidly in the lung tissue during the first few weeks without involvement of other organs. The increase in number, size and confluence of lung granulomas paralleled the multiplication of MLM which could be found both intracellularly and extracellularly. It is postulated that extracellular bacteria may find their way to the bloodstream and thus spread to other visceral organs. Extensive destruction of alveoli and occupation of airspaces by lepra-like cells invariably occurred as the disease progressed.

Animals↗
PubMed1988

The proportion of suppressor-inducer T-lymphocytes is reduced in recurrent aphthous stomatitis.

A flow cytometric analysis of peripheral blood lymphocytes was undertaken in recurrent aphthous stomatitis patients. The project aimed at detecting differences within lymphocyte subsets using type-specific monoclonal antibodies. Peripheral blood samples were taken from RAS patients in both active and remission phases of the disease and from a group of healthy control subjects. There were no statistical differences between the active and remission phases within any of the lymphocyte subsets examined. There was, however, a significant difference between the RAS group and the control group. RAS patients have depressed CD4+ cell numbers and elevated CD8+ cell numbers. The CD4:CD8 ratio is also depressed. A dissection of the CD4+ subset shows raised numbers of CD4+, 4B4+ lymphocytes and depressed numbers of CD4+, 2H4+ lymphocytes. Previous studies have shown disruption of peripheral blood lymphocyte numbers in Behçet's syndrome. A similar pattern has now been shown in uncomplicated cases of minor RAS.

Adult↗
PubMed1988

Synovial involvement by Mycobacterium marinum. A histopathological study of 25 culture-proven cases.

The present culture-proven cases are contrary to the generally held view that infection with Mycobacterium marinum is habitually a superficial infection without potentially serious consequence. A wide spectrum of pathological lesions may be seen in the synovium and adjacent tissues in patients infected by M. marinum. Variations in the morphology of the inflammatory reaction occurs both between cases and, to a lesser extent, in different areas of individual cases. The inflammation ranges from the common non-specific diffuse form, to lesser areas of focal non-caseating lesions, to rarer focal caseating types of granulomatous reaction, and can include an acute inflammatory cell component. Fibrinous exudate on the synovial surface is a recurrent feature and is often the site harbouring most acid-fast bacilli. The variation of inflammatory reaction with time and the possible effects of local steroid injection are discussed.

Adolescent↗
PubMed1987

DNA fragmentation in childhood T-cell acute lymphoblastic leukaemia.

DNA isolated from 12 patients with childhood acute lymphoblastic leukaemia (T-ALL), analysed by gel electrophoresis exhibited a degradation pattern of increasing nucleosome repeat size, similar to that observed when nuclei from normal control cells are incubated with micrococcal nuclease. None of a group of adult T-ALL showed this fragmentation, nor was the pattern observed in normal control T-cells, cells from patients with a number of other forms of leukaemia, or in B-lymphoblastoid cells under the same incubation conditions. This phenomenon appears to be related to the changes in DNA that occur in glucocorticoid-induced cell death in mouse thymocytes, radiation-damaged spleen cells, and in cytotoxic T-cells deprived of interleukin 2. The method described here promises to be a reliable, simple approach to the characterization of T-ALL in childhood and may aid in the clinical management of this form of leukaemia.

Adolescent↗
PubMed1987

Mycobacterium marinum infection of the hand and wrist. Results of conservative treatment in twenty-four cases.

Inadequate débridement, extensive scarring, and breakdown of the wound have been commonly encountered after surgical débridement has been employed as the initial treatment of infection with Mycobacterium marinum involving the deep structures of the hand. Because of our disappointment with the results of this form of treatment, from 1982 to 1986 we treated twenty-four patients who had such an infection with rifampicin and ethambutol after a diagnostic biopsy was done. Surgical treatment was deferred until it was determined that the infection had not been controlled by the chemotherapy. The clinical outcome for these patients could be divided into three patterns: eleven patients (Group I) had a good result with no complications, three patients (Group II) had delayed healing of the wound, and ten patients (Group III) did not have a good response to conservative treatment and required one or more surgical débridements. Complications were sometimes associated with use of the drugs, and loss of visual acuity was a concern in three patients. In twenty-one (87 per cent) of the patients, at follow-up the function of the treated hand was equal to that of the other hand. Persistent pain, a discharging sinus, and previous local injection of steroids were unfavorable prognostic factors. If these factors are present, surgical débridement is advised.

Adolescent↗