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R J Collins

Publications and source records attributed to R J Collins.

At least 55 records · Page 3Linked to original sources
PubMed1991

In vitro OKT3-induced mitogenesis in selenium-deficient patients on a diet for phenylketonuria.

Patients with phenylketonuria (PKU) are frequently deficient in the essential trace element selenium (Se), because of their very low protein diet. Using two approaches to investigate T-cell response to proliferative signaling, viz, mitogenesis caused by the monoclonal antibody OKT3 and the plant lectin phytohaemagglutinin (PHA), we demonstrated significantly reduced responses to optimal concentrations of OKT3 in a group of PKU patients with reduced serum Se compared with a normal group (p = 0.0005) and with a group of PKU patients whose serum Se was normal (p = 0.0023). The response of the Se-deficient group to optimal levels of PHA did not differ from that of the normal controls or from that of Se-normal PKU patients. A dose-dependent relationship between serum Se levels and mitogenic response was evident for OKT3 (r = 0.34, p = 0.0154), but not for PHA (r = -0.02, p = 0.9086). We suggest that the reduced response to OKT3 mitogenesis in Se-deficient PKU patients is possibly the consequence of impaired Se-dependent metabolic activity, which affects mitogenic signaling via the T cell antigen receptor (TCR/CD3) complex.

Adolescent↗
PubMed1991

Biliary cystadenoma and cystadenocarcinoma: some unusual features.

Biliary cystadenoma and cystadenocarcinoma are rare tumours which have a good prognosis after complete surgical removal. Correct pre-operative diagnosis depends on the imaging characteristics of the tumours. We have observed some unusual features including multifocal tumours with attachment to other abdominal organs, tumour presenting as cholangitic abscess, and distant metastasis after apparently complete resection by hemihepatectomy.

Adult↗
PubMed1991

Unusual pathology of the vertebrae and dorsal fin rays of the yellow conger pike eel, Congresox talabonoides, from Hong Kong.

Congresox talabonoides, the yellow conger pike eel, caught near Hong Kong, shows a high incidence of abnormal vertebrae and dorsal fin rays. Of 423 C. talabonoides examined during 1967-69, 244 (57.7 per cent) had a total of 999 macroscopically enlarged vertebrae, but 100 of each of the related species Muraenesox bagio and M. cinereus were unaffected. The gross and histological changes were investigated in 20 freshly caught specimens. Small eels (less than 80 cm) were not affected. Bigger specimens showed symmetrically enlarged, densely calcified vertebrae and fin rays, with more bones affected as the fish grew larger. X-rays showed that the calcification was uniform; various degrees of change were seen in X-rays of the fin rays, but the vertebrae appeared either highly radio-dense or normal. Histological examination showed deposition of dense cancellous lamellar bone, which appeared organized rather than random. In the case of the fin rays, the new bone surrounded each ray, but in the vertebrae the normal structure was replaced, then expanded. There is no clearly comparable pathology in mammals. Similar lesions in other species of fish have been attributed to toxins, but the incidence in C. talabonoides seems exceptional.

Animals↗
PubMed1991

Cholinergic activity of acetylenic imidazoles and related compounds.

A series of acetylenic imidazoles related to oxotremorine (1a) were prepared and evaluated as cholinergic agents with in vitro binding assays and in vivo pharmacological tests in mice. 1-[4-(1H-Imidazol-1-yl)-2-butynyl]-2-pyrrolidinone (1b) was a cholinergic agonist with one-half the potency of oxotremorine. Analogues of 1b with a 5- or 2-methyl substituent in the imidazole ring (compounds 1c and 1g) were cholinergic partial agonists. Analogues of 1b with a methyl substituent at the 5-position in the pyrrolidinone ring (7b) or at the alpha-position in the acetylenic chain (8b) were antagonists. Various analogues of these imidazole acetylenes where the pyrrolidinone ring was replaced by an amide, carbamate, or urea residue were prepared. Several compounds which contained 5-methylimidazole as the amine substituent were partial agonists. The activities of the imidazole compounds are compared with those of the related pyrrolidine and dimethylamine analogues. Agonist and antagonist conformations for these compounds at muscarinic receptors are proposed.

Acetylene↗
PubMed1991

Effects of cycloheximide on B-chronic lymphocytic leukaemic and normal lymphocytes in vitro: induction of apoptosis.

A number of reports indicate that protein synthesis is a requirement for the occurrence of apoptosis. In this study, the effect of the protein synthesis inhibitor cycloheximide (CHM) on spontaneous apoptosis of B-chronic lymphocytic leukaemia (B-CLL) cells, previously shown to occur when they are cultured in RPMI-1640 medium with autologous or heterologous serum, was examined. No definite inhibition of apoptosis was observed. Indeed, CHM-treatment augmented apoptosis in the B-CLL cultures and also induced apoptosis of cultured normal peripheral blood lymphocytes. Augmentation was dose-dependent for B-CLL cells over the concentration range 10(-6) M (0.28 micrograms ml-1) to 10(-2) M (2800 micrograms ml-1), resulting in 9% to 98% apoptosis respectively by 24 h of culture (r = 0.619, P = 0.0008). Normal lymphocytes were affected by CHM over the range 10(-4) M to 10(-2) M, resulting in 7% to 74% apoptosis respectively (r = 0.794, P = 0.0001). Inhibition of protein synthesis in these cells by CHM was virtually complete at a concentration of 10(-3) M. The findings are in accord with some recent reports indicating that suppression of protein synthesis by CHM does not inhibit apoptosis in all circumstances. They also illustrate the marked susceptibility of B-CLL cells, compared with normal lymphocytes, to the induction of apoptosis by this drug. The manner in which CHM triggers apoptosis of some cell types is at present uncertain.

Antigens, CD↗
PubMed1991

Viral-like characteristics of particle aggregates in a lymphoblastic cell line.

A lymphoblastic cell line (K45) established from a child with acute lymphoblastic leukemia (ALL) is characterized by a profusion of intracytoplasmic particle aggregates (PA) similar in morphology to those occurring in fresh childhood ALL cells. The PA in K45 cells were examined for morphology and capacity for nucleic acid synthesis to test the hypothesis that they are identical to those in fresh ALL cells, and also to identify characteristics which might distinguish PA from cell organelles and which might determine if they are viral-like. In contrast to cell organelles, the PA in both K45 and ALL cells were found to be characterized by a localized thickening of the particle wall. Furthermore, autoradiography of K45 cells showed uptake by PA of 3H uridine rather than 3H thymidine indicating an RNA composition. The presence of PA in profusion was associated with, but preceded necrotic death of K45 cells. These combined features suggest that the PA in K45 and in ALL cells are identical, that they are distinct from cell organelles, are not formed as a consequence of the initiation of cell death and that, while their exact nature remains unknown, a viral origin cannot be excluded.

Autoradiography↗
PubMed1991

Malignant melanoma of the female genital tract. A report of nine cases in the Chinese of Hong Kong.

Ten cases of malignant melanoma of the female genital tract were diagnosed in Chinese patients in Hong Kong over the 12 yr period from 1978 to 1990. Of the 9 cases considered here, 4 involved the vagina alone, 2 the vagina and cervix, 2 the uterine cervix alone, and 1 occurred on the vulva. Thus, contrary to the usual reported distribution, the vulva was an uncommon site. While the mean age of the patients was 58 yrs, 2 patients were in their thirties and both had a history of a recent pregnancy. Vaginal bleeding or discharge were the presenting symptoms in most cases. The primary origin was confirmed histologically in 6 of the 9 cases and all were of the mucosal lentiginous type. Deep invasion, beyond 3 mm, was present in all cases at the time of diagnosis. Five patients died of the disease 2-22 months after diagnosis. The 4 surviving patients were clinical Stage I and II (FIGO) when diagnosed and have a median survival of 18 months to date. Both the FIGO clinical stage and Breslow's tumor thickness proved to be good prognostic indicators.

Adult↗
PubMed1990

A clinical and flow cytometric analysis of patients with nasopharyngeal cancer.

Abnormal cellular DNA content, a hallmark of malignancy, is known to be an important prognostic factor in many human solid tumors; however, no data have been published on whether cellular DNA content carries prognostic significance for patients with nasopharyngeal cancer (NPC). Archival, formalin-fixed, paraffin-embedded pathology specimens representing pretreatment tissue biopsies from 55 patients (41 men and 14 women) with NPC were analyzed for cellular DNA content in a retrospective fashion from 1968 to 1988. Individual tumors were classified as either lymphoepithelioma, squamous cell, or anaplastic carcinoma, and were staged according to International Union Against Cancer (UICC) criteria. All patients were treated with curative intent using a 4 to 6 MeV linear accelerator to total doses ranging from 50 to 60 Gy in 4 to 6 weeks. The overall 5-year actuarial survival for all 55 patients was 44.4% (men, 41%; women, 52%). Survival by T stage was as follows: T1, 65%; T2, 51%; T3, 36%; and T4, 27%. Similarly, the 5-year survival rate declined as the bulk of nodal metastases increased: N0, 62%; N2, 50%; N3, 37%; and N1, 25%. Patients who had anaplastic carcinoma had a 5-year survival of 73%, those with lymphoepithelioma had a 60% survival, and those with squamous cell cancer (SCC) had a 30% survival. There was a statistically significant difference in 5-year survival between patients with SCC and those with nonkeratinizing histologies (P less than 0.05). In addition, there was a significant association between patients older than 40 years of age with SCC and patients younger than 40 years of age with nonkeratinizing malignancies (P less than 0.01). Of the 55 tumors successfully analyzed, 22 (40%) were diploid and 33 (60%) were aneuploid. The mean coefficient of variation (CV) of all 55 samples was 6.17%. There was no significant difference in 5-year survival between patients with diploid and those with aneuploid tumors (48% versus 42%). Furthermore, there was no statistically significant survival difference between aneuploid and diploid tumors within any one histologic subgroup. There was also no significant survival difference related to the DNA index. The results indicate that the extent of local tumor spread is still the most important prognostic factor for patients treated with radiotherapy for NPC. The data support the conclusion that patients with lymphoepithelioma and anaplastic carcinomas have a superior survival to patients with squamous cell carcinoma.(ABSTRACT TRUNCATED AT 400 WORDS)

Actuarial Analysis↗
PubMed1990

Etoposide combination chemotherapy in refractory ovarian malignant germ cell tumor.

Thirty-three patients with malignant germ cell tumor of the ovary received postoperative vincristine, dactinomycin, and cyclosphosphamide (VAC) treatment. Eight failed VAC treatment and received etoposide, bleomycin, and cisplatin (PEB) combination chemotherapy. Three were cured and remained disease free 24-79 months after completion of PEB therapy.

Carboplatin↗
PubMed1990

Cell death induced in a murine mastocytoma by 42-47 degrees C heating in vitro: evidence that the form of death changes from apoptosis to necrosis above a critical heat load.

The pathogenesis of heat-induced cell death is controversial. Categorizing the death occurring after various heat loads as either apoptosis or necrosis might help to elucidate this problem, since it has been shown that these two processes differ in their mode of initiation as well as in their morphological and biochemical features. Log-phase cultures of mastocytoma P-815 x 2.1 were heated at temperatures ranging from 42 to 47 degrees C for 30 min. After 42 degrees C heating a slight increase in apoptosis was observed morphologically. However, after heating at 43, 43.5 and 44 degrees C, there was marked enhancement of apoptosis, and electrophoresis of DNA showed characteristic internucleosomal cleavage. With heating at 45 degrees C both apoptosis and necrosis were enhanced, whereas at 46 and 47 degrees C only necrosis was produced. DNA extracted from the 46 and 47 degrees C cultures showed virtually no degradation, which contrasts with the random DNA breakdown observed in necrosis produced by other types of injury; lysosomal enzymes released during heat-induced necrosis may be inactivated at the higher temperatures. It is suggested that apoptosis following heating may be triggered either by a limited increase in cytosolic calcium levels resulting from mild membrane changes or by DNA damage. Necrosis, on the other hand, is likely to be a consequence of severe membrane disruption.

Animals↗
PubMed1990

Placental site trophoblastic tumor: with features between an exaggerated placental site reaction and a placental site trophoblastic tumor.

Chorionic villi, whose presence in cases of trophoblastic disease is normally used to exclude both a choriocarcinoma and placental site trophoblastic tumor (PSTT), were present in the initial uterine curettage specimen of a trophoblastic tumor. The lesion shared morphologic features of both an exaggerated placental site reaction and a PSTT. There was infiltration of the posterior wall of the uterus by small clusters and isolated cells which had a prominent affinity for vessels and resembled a usual placental bed reaction. There was, however, deep involvement of myometrium with extension to the cervix, and the condition persisted for 5 months after uterine evacuation. Because different treatment is entailed, identification of this lesion as a tumor of nonvillous trophoblast is also of great importance in a region where the more usual forms of trophoblastic disease represent a declining but not infrequent event. When products of gestation are examined, the possibility of a PSTT should be considered and the clinician alerted if there is a suggestion of excessive intermediate trophoblastic activity, regardless of the presence of chorionic villi. While this may result in the unnecessary followup of some cases, it would permit, with the aid of serial beta-hCG and HPL levels, the earlier detection of PSTTs.

Adult↗
PubMed1990

Human papillomavirus infection in the cervix of pregnant females in Hong Kong.

Routine cytological examination and HPV-DNA probing were performed on cervical cells obtained from 215 pregnant Chinese females. The procedure utilized the specific binding of a mixture of complementary [32P]-labelled RNA probes to membrane-bound target HPV DNA types 6, 11, 16, 18, 31, 33 and 35. Positive results for HPV-DNA were obtained in 11/215 (5%) of the cases. The cervical smears were routinely processed and in 3/215 (1.5%) cases a cytological diagnosis of wart virus infection was made. All three were included in the 11 probe-positive cases. Using similar molecular biological techniques, pregnant Western females have an incidence of HPV infection of the cervix which is up to five times that of the present series. This is an unexpected finding in view of the fact that the incidence of cervical cancer is higher in Chinese women than American women.

Female↗
PubMed1990

Vaginal metastases in gestational trophoblastic disease.

From 1976 to 1988, 320 patients with gestational trophoblastic disease were treated in the Department of Obstetrics and Gynaecology, University of Hong Kong. Eighteen patients had vaginal metastases. The clinical features and behaviour of the disease were analysed. The prognosis depends mainly on the extent of the disease. Similar favourable response to chemotherapy was observed in low-risk patients with vaginal metastases.

Adult↗
PubMed1990

Differentiation of monochorionic and dichorionic twin placentas by antenatal ultrasonic evaluation.

The prenatal identification of various types of placentation is important for the antenatal management of twin pregnancies. Such classification can be achieved with the use of ultrasound examination. In 32 cases of twin pregnancy the intervening septum was classified as either a thick (dichorionic) or thin (monochorionic) type. Macroscopic and microscopic examination of the placenta after delivery confirmed the ultrasound diagnosis in 24 of the 30 cases, an accuracy of 80%.

Cardiotocography↗
PubMed1990

Rate nephelometric determination of rheumatoid factor: comparison between Kallestad QM-300 and Beckman ICS-II (RF) methods.

The Kallestad Corporation recently suggested that their new buffer system for the nephelometric detection of rheumatoid factor conferred advantages over existing systems. Two rate nephelometric procedures, the Kallestad QM-300 and the Beckman ICS-II (RF), were therefore compared. Sera (n = 157) were selected on the basis of a previous ICS-II value. The results on the QM-300 of sera with an initial rheumatoid factor value of less than 400 IU identified two groups. Group 1 (n = 109) showed a good correlation with the ICS-II method while group 2 (n = 13) was highly discordant with the QM-300, producing significantly higher values. The values of 35 sera with an initial rheumatoid factor of greater than 400 IU were likewise highly discordant, with the QM-300 producing significantly lower values. Dilution recovery experiments implied that the Beckman buffer was likely to be contributory. As the formulae of the buffers remain proprietary, the reasons for the differences are speculative. The findings could be taken to indicate that the Kallestad value is a more accurate indicator of the quantity of rheumatoid factor than the Beckman value.

Buffers↗
PubMed1990

Evaluation of semiautomated procedure for lymphocyte subset analysis.

The findings of recent surveys indicate a need for standardisation in lymphocyte subset analysis by flow cytometry. Major areas of concern are the methods used for labelling subsets and the choice of appropriate monoclonal antibodies. A standard dual colour manual whole blood lysis technique for flow cytometry was compared with the recently available Coulter Q-Prep EPICS technique. Overall, there was no significant difference (Student's t test) between the use of anticoagulated blood treated with heparin or EDTA. When normal subjects were examined there was a decrease in the absolute number of CD3+ and Leu-7+/CD8- cells and an increase in CD19+ and CD20+ cells. When human immunodeficiency virus (HIV) antibody positive subjects were examined there was a significant decrease in the absolute number of CD2+, CD3+, CD4+ and Leu 7+/CD8- cells and an absolute increase in CD19+ and CD20+ cells. CD8+ cells were decreased only with the Cyto-Stat reagents. Occasionally, the Q-Prep did not lyse the red cells efficiently. While the Q-Prep EPICS system has the potential to standardise and automate the labelling procedures used in lymphocyte subset analysis, further refinement, such as the choice of monoclonal antibodies or alternative preparative reagents, may be required to resolve the cause of the discordant findings between the two approaches.

Antibodies, Monoclonal↗
PubMed1990

Cellular and biochemical characterization of the anti-inflammatory effects of DuP 654 in the arachidonic acid murine skin inflammation model.

The possible utility of DuP 654, a potent 5-lipoxygenase inhibitor, for treating human inflammatory skin disease was investigated in murine skin treated with 1.0 mg arachidonic acid (AA). When DuP 654 was applied to murine skin treated with AA, it inhibited the resulting inflammation and influx of cells. High performance liquid chromatography and radioimmunoassay analysis of lipid extracts from AA-treated ears indicated that the influx of polymorphonuclear leukocytes (PMN) was temporally preceded by an appearance of significant amounts of 5-HETE (6.7 +/- 1.4 ng/ear) and Leukotriene B4 LTB4 0.92 +/- 0.2 ng/ear) when compared with extracts of untreated ears (5-HETE, 02 +/- 0.3 ng/ear; LTB4, less than 0.1 ng/ear). The levels of the 5-lipoxygenase products were reduced by treatment with 10 micrograms/ear DUP 654. Lipid extracts from AA-treated ears contain chemotactic activity for human PMN and this chemotactic activity in the AA-treated ears could be reduced but not eliminated by immunosorption with anti-LTB4 antibodies coupled to protein A-agarose. The appearance of the chemotactic activity was inhibited by DuP 654. Taken together, these data suggest that DuP 654 may have utility in human inflammatory skin disease.

Animals↗