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Biomedical subjects

R J Collins

Publications and source records attributed to R J Collins.

At least 91 records · Page 5Linked to original sources
PubMed1986

Rearrangements of T-cell receptor beta-chain genes in human leukaemias.

Rearrangements of the T-cell receptor (TCR), beta-chain genes and immunoglobulin (Ig) heavy chain genes in several T-cell leukaemias (T-ALL and ATL), and some B-cell and myelogenous leukaemias were investigated. Two out of 15 cases of T-cell leukaemia tested failed to show a rearrangement pattern of TCR beta genes although both expressed mRNA for this gene. The remaining 13 cases showed diverse patterns of rearrangements involving either C beta 1, C beta 2 or both. C beta 1 but not C beta 2 was deleted in some of the T-cell leukaemias. Polyclonal T cells from four normal individuals showed the germ line pattern and an additional two bands in Hind III digested DNA. Except for one, all cases of C-ALL (B-cell leukaemia) showed a rearranged JH locus which was not evident in any of T-cell leukaemias studied. One case of B-cell leukaemia showed a rearrangement of both TCR beta genes and JH genes. The results of these studies suggest that rearrangement of TCR and Ig genes occurs at a very early stage of differentiation of stem cells and does not appear to play a direct role in leukaemogenesis per se.

Antigens, Neoplasm↗
PubMed1986

Bilateral amyloid tumours of the breast.

An 82 year old woman with bilateral amyloid tumours of the breast is described. Clinically, the breast masses were hard and were suspicious of carcinoma. Investigation revealed no evidence of systemic amyloidosis or amyloid related illness. Microscopically there was no neoplasia. Instead there was extensive fibrosis with amyloid deposition in perivascular periductal areas and also in the intervening stroma. The presence of amyloid was confirmed by special stains and by electron microscopy.

Aged↗
PubMed1986

Non-tropical idiopathic splenomegaly and chronic T cell lymphocytosis.

Non-tropical idiopathic splenomegaly (NTIS) is thought to predispose to the development of lymphoid neoplasia of B-cell type. We report a case of NTIS that evolved into a T-lymphoproliferative disorder. Review of the literature suggests that this type of evolution is not uncommon. The role of splenectomy in this progression is discussed.

Adult↗
PubMed1986

Altered chromatin in childhood leukaemic lymphoblasts: association with virus-like particles.

An electron microscopic examination was made of masses identified as altered heterochromatin in the cytoplasm of childhood leukaemic lymphoblasts, and their relation to 'virus-like' particles (VLP). The masses were found to occur more frequently in leukaemic lymphoblasts than in normal lymphocytes, but abnormally frequent occurrence was a feature of non T rather than T or B lymphoblasts. Although these masses may be derived by phagocytosis of dead cells or cellular material, a more likely origin is by detachment of altered portions of the containing cell's own nucleus. Such in situ alterations in nuclei were seen in leukaemic lymphoblasts but not in normal lymphocytes. A close relation demonstrated between altered chromatin and VLP might suggest that VLP are a response to the presence of damaged chromatin. However, the occurrence in some VLP of solid cores and budding might make it more likely that VLP are viral, with chromatin damage as a morphologically recognizable cytopathic effect of their activity.

B-Lymphocytes↗
PubMed1985

Behavioral effects of a novel kappa opioid analgesic, U-50488, in rats and rhesus monkeys.

U-50488 [trans-3,4-dichloro-N-(2-(1-pyrrolidinyl) cyclohexyl)-benzeneacetamide] is a structurally novel analgesic reported to have specific kappa opioid receptor agonist properties. Potent antinociceptive activity was demonstrated in rhesus monkeys and the effect was reversed by naloxone. The overt behavioral effects of U-50488 at supra-analgesic doses more closely resembled those of ethylketocyclazocine (EKC) than morphine. In monkeys trained to discriminate a 10-micrograms/kg dose of EKC from saline, the stimulus effects generalized completely to U-50488 and other kappa agonists (e.g., bremazocine, cyclazocine), but not to the pure mu agonists. Like the other kappa agonists, U-50488 produced diuresis in monkeys by a naloxone-sensitive mechanism. In drug-naive rats offered continuous opportunity to self-administer drugs IV, most rats self-administered morphine or EKC, but none of the rats self-administered U-50488 at a rate above that of a group offered saline. Rats with continuous IV infusion of U-50488 for 3 weeks exhibited few abstinence signs and no weight loss when challenged with an injection of naloxone or after abrupt cessation of drug infusion. These experimental results support the previous reports in mice that U-50488 is a very selective kappa opioid agonist in rats and rhesus monkeys.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1984

Melanoma in the Chinese of Hong Kong. Emphasis on volar and subungual sites.

In the 19-year period from 1964 to 1982, a total of 65 primary melanomas at all sites were recorded. Of the 43 primary cutaneous melanomas in Chinese patients, 32 (74%) occurred at volar or subungual sites. The foot contributed 56% of all cutaneous melanomas with the majority (83%) occurring on the plantar surface. Subungual melanomas, with one exception, presented in the nailbed of the great toe or thumb. The following is the distribution of volar or subungual melanomas by histologic type: acral lentiginous 51.7%, superficial spreading 20.7%, nodular 6.9%, and unclassifiable 20.7%. Thickness was greater than 3 mm in 81.5% of cases, and in 37% it was greater than 9 mm. A prior pigmented lesion was noted in 15 of the volar or subungual cases. The Chinese, like other racial groups with intermediate pigmentation, appear to have a preponderance of melanomas on the feet with a frequency between that of whites and the very high one seen in blacks.

Adult↗
PubMed1984

Prediction of abuse liability of drugs using IV self-administration by rats.

A total 31 psychoactive drugs were offered to groups of naive rats for IV self-administration and an injection rate greater than that for rats offered only saline indicated reinforcement. Two protocols were used: in the first, rats were offered drug at a selected dose for 5 days, then the dose was reduced by 1 log unit (to 0.1 the original dose) for an additional 4 days; in the second, rats were offered saline for 3 days as a "prescreen' to eliminate rats with high or low operant-injection rates. Drug was offered to acceptable rats for 5 days, then the dose was reduced 0.5 log unit (to 0.32 the original dose) for 5 more days. A scoring system, based upon the injection rates during the last 3 days of each period, describes the reinforcing action. Scores were dose-related. Tests on both protocols gave similar results. Data from monkey studies have been reported for 27 of the drugs tested. Of these drugs, 18 were reinforcers and six were nonreinforcers in both species, nalorphine and ethylketazocine were reinforcers only in rats, and ethanol was a reinforcer only in monkeys.

Animals↗
PubMed1984

Changes in T-lymphocytes and response to high-dose gamma-globulin therapy in idiopathic thrombocytopenic purpura.

Peripheral blood lymphocytes were studied using OKT3, OKT4 and OKT8 monoclonal antibodies in patients with idiopathic thrombocytopenic purpura ITP) before and after high dose gammaglobulin therapy. Total lymphocyte counts increased in 8 of 10 patients studied within 16 weeks of presentation (acute ITP) but decreased in all 6 with chronic (6 months-14 years) thrombocytopenia (P = 0.003). A relative increase in the proportion of inducer-helper (OKT4) cells was seen in 5 of 6 patients with sustained responses whereas there was no clear cut change or a relative increase in suppressor-cytotoxic (OKT8) cells in 7 or 9 with transient responses. The data suggest that short term gammaglobulin therapy may induce sustained responses by immunoregulation of T-lymphocyte subsets.

Adolescent↗
PubMed1984

Determination of biological activity of adinazolam and its metabolites.

Adinazolam and its metabolites inhibit [3H]flunitrazepam binding in-vitro. The binding affinities of these compounds is significantly enhanced in the presence of 10-5 M muscimol, indicating that both adinazolam and its metabolites are benzodiazepine agonists. In-vivo metabolism of adinazolam results in the formation of active metabolites.

Animals↗
PubMed1984

Immune complexes in ovarian cancer: association between IgM class complexes and antinuclear autoantibodies in ascitic fluid.

Samples of ascitic fluid from patients with ovarian cancer were analyzed for autoantibodies to nuclear and cytoplasmic antigens and for immune complexes (ICs) detectable by the Clq deviation and polyethylene glycol (PEG) precipitation (either IgG or IgM class) assays. The predominant autoantibody was antinuclear (ANA); this was detected in 29 of 58 samples (59% showing the homogeneous and 41% the speckled pattern). The antibody was not reactive to saline extractable nuclear antigens. A strong association between this autoantibody and the PEG-precipitated IgM class ICs was shown, suggesting the possible participation of this autoantibody in IgM class ICs formation. The lack of association between C1q-reactive and IgG class ICs and the autoantibodies indicates that the IgG class ICs may be more related to the tumor.

Adult↗
PubMed1983

Mycobacterium marinum infection of the hand involving deep structures.

Five patients with Mycobacterium marinum infection of the hand involving deep structures were seen recently. Four of them were fishermen. Hydrocortisone injection or simple incision and drainage led to worsening of the infection. The clinical presentation, operative finding, and histopathologic and microbiologic features were quite similar in all five patients. Extensive debridement and therapy with ethambutol and rifampin led to satisfactory results in four patients while biopsy and therapy in the fifth patient seemed to offer another form of acceptable treatment.

Adult↗
PubMed1983

General practice residency training and subsequent clinical production.

An increasing number of newly graduated dentists are entering general practice residency (GPR) training programs. These programs have been suggested as a means of coping with a rapidly expanding knowledge base without resorting to a mandatory fifth year of predoctoral education or increasing specialization within the profession. This study examines the relationship of general practice training to subsequent clinical production among dentists employed by the Indian Health Service. The quantity and type of services provided by a group of dentists with previous GPR training were compared to services provided by a group without similar training. After adjustment for years of service and number of dental auxiliaries, no significant differences between the groups were found. However, no inferences can be made about the appropriateness or quality of the services delivered based solely upon productivity data.

Clinical Competence↗