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Biomedical subjects

R J Collins

Publications and source records attributed to R J Collins.

At least 37 records · Page 2Linked to original sources
PubMed1993

Cervical human papilloma virus infection of women attending social hygiene clinics in Hong Kong.

OBJECTIVE: To find the prevalence of HPV infection in women attending a sexually transmitted disease clinic in Hong Kong. METHOD: Cervical HPV infection was identified by cervical cytology and DNA filter in-situ-hybridization (Virapap) techniques in 207 women attending a social hygiene clinic. Other risk factors for cervical cancer were assessed and any association with HPV infection was sought. Statistical analysis was carried out using the chi 2-test. RESULT: The prevalence of HPV infection in the 207 Chinese women was 8.2% by cervical smear and 12.6% by DNA filter in-situ-hybridization. Risk factors for cervical cancer were not significantly associated with HPV infection in this group, 95% of whom were prostitutes. CONCLUSION: The prevalence of HPV infection in this group at high risk for cervical cancer is higher than in low-risk pregnant women, however the prevalence of HPV infection in Hong Kong is at the low end of the range of figures quoted for Caucasians. The cause of such a low prevalence is yet to be determined.

Adolescent↗
PubMed1993

Intravenous leiomyomatosis with intracardiac involvement.

Intravenous leiomyomatosis is considered to be a rare neoplastic disease usually arising from uterine fibromyomata, but its true incidence may be under-recognized. Mortalities from this condition are usually the result of intracardiac involvement. A case report of successful treatment of intravenous leiomyomatosis with intracardiac extension is presented, together with a review of the existing literature concerning this rare condition.

Female↗
PubMed1993

Epstein Barr virus in carcinoma of the cervix.

A group of young patients with invasive carcinoma of the cervix and an age-matched control group were investigated for the presence of Epstein Barr virus (EBV) DNA in cervical biopsies using the polymerase chain reaction. The carcinoma group was further analyzed to evaluate possible associations between the presence of EBV and other prognostic parameters, such as stage, lymph node involvement, and histological tumor type. EBV DNA was found in 20 of 40 (50%) of the carcinoma samples and in 20 of 39 (51%) of the cervical tissues in the control group (p > 0.5). No statistically significant relationship could be noted between the presence or absence of EBV DNA and the effects of other prognostic parameters. In comparison with other studies using similar techniques, this study documented a higher percentage of positive EBV cases in both normal and carcinoma cervical samples. In both groups there was a similar number of positive cases. These results suggest that theories on the possible role played by EBV in the pathogenesis of cervical carcinoma may need to be reconsidered.

Adult↗
PubMed1993

The significance of proliferating cell nuclear antigen in human trophoblastic disease: an immunohistochemical study.

The expression of proliferating cell nuclear antigen (PCNA) in human trophoblastic disease was assessed immunohistochemically in tissue from 29 spontaneous abortions, 33 partial moles, 40 complete moles and 23 choriocarcinomas using the monoclonal antibody PC10. PCNA immunoreactivity occurred predominantly in the cytotrophoblasts in each of the four types of tissues. Quantitative analysis showed that the choriocarcinoma group gave a statistically significant higher PCNA index than the other three. There was no significant difference between the groups of spontaneous abortion, partial or complete mole. Sixteen of the 73 patients with partial and complete moles developed persistent gestational trophoblastic disease and there was no significant difference between the patients requiring chemotherapy and those who did not. We conclude that choriocarcinoma has a significantly higher PCNA proliferative index whilst hydatidiform moles cannot be distinguished from abortions by such analysis. The PCNA index does not appear to be useful in predicting the progression of molar pregnancies to persistent trophoblastic diseases.

Abortion, Spontaneous↗
PubMed1993

Dental manpower planning in the Indian Health Service.

As a public health agency, the Indian Health Service (IHS) must plan for the needs of the entire American Indian and Alaskan Native (AI/AN) population and distribute resources as equitably as possible. To facilitate this process, the IHS has developed a manpower planning model to provide for the distribution of dental providers based upon the dental needs of the AI/AN population and within the limits of annual appropriations of funds. This paper briefly describes the original IHS Dental Program manpower planning model and the development of modifications over time. The need-based approach to manpower planning developed by the IHS Dental Program has exhibited utility and flexibility over time. It allows a determination of clinic size (number of operatories) and dental staffing requirements, and may be generalizable to other public health programs if an accurate assessment of utilization rate and treatment need can be made for the defined population. Nonetheless, the availability of resources in public programs is subject to the compromises inherent in the political process; thus, the use of a manpower planning model alone may not be sufficient to ensure the equitable distribution of dental resources and dental providers.

Dental Health Services↗
PubMed1993

Expression of c-myc and c-fms oncogenes in trophoblastic cells in hydatidiform mole and normal human placenta.

AIMS: To compare the expression of c-myc and c-fms proto-oncogenes in the placenta and hydatidiform mole. METHODS: Twelve hydatidiform moles and six induced abortion cases were collected. c-myc and c-fms proto-oncogene expression was analysed by northern blot hybridisation and immunohistochemical staining. RESULTS: The results of northern blot hybridisation analysis showed that c-fms was expressed more strongly in hydatidiform moles compared with normal placenta of similar gestational age. Moreover, c-fms mRNA concentrations increased with more advanced gestational age in moles but not in normal placentas. c-myc expression was very low in hydatidiform moles and normal placentas. Both oncogenes, however, had no direct correlation with the clinical course of the molar pregnancies. CONCLUSION: The difference in c-fms expression between hydatidiform moles and normal placentas suggests that c-fms may have a role in the development of molar pregnancies.

Antibodies, Monoclonal↗
PubMed1993

Epstein-Barr virus in carcinoma of the vulva.

AIMS: To detect the presence of Epstein-Barr virus (EBV) in cases of vulval carcinoma in Chinese patients living in Hong Kong. METHODS: Formalin fixed, paraffin wax embedded blocks from eight cases of vulval carcinoma and six age matched controls of non-neoplastic vulval tissue were analysed for the presence of EBV DNA using the polymerase chain reaction (PCR). RESULTS: EBV DNA was detected in only one of the eight cases of vulval carcinoma cases while it was detected in four out of the six control cases. CONCLUSIONS: There is no demonstrable association between EBV and vulval carcinoma. Detection of EBV in non-neoplastic vulval epithelium highlights its ubiquitous presence in the lower female genital tract.

Aged↗
PubMed1993

Intracytoplasmic barium salts in pleural fluid.

Cytological examination of the pleural effusion fluid obtained from a 66-yr-old Chinese lady showed numerous intra- and extracytoplasmic colourless refractile non-birefringent crystals. X-ray analysis of the crystals identified barium salts. On further inquiry, it was learnt that the fluid obtained had been placed in a specimen bottle provided by the x-ray department. This container was presumably contaminated with barium salts. The case highlights an unusual aspect of specimen contamination and the usefulness of x-ray analysis in the identification of crystals/substances.

Aged↗
PubMed1992

Synthesis, chemical, and biological properties of vinylogous hydroxamic acids: dual inhibitors of 5-lipoxygenase and IL-1 biosynthesis.

Vinylogous hydroxamic acids (3-(N-hydroxy-N-alkylamino)-2-propen-1-ones, VHA) were prepared as antiinflammatory agents. The synthesis, chemical properties, and in vitro biological activities of these relatively unexplored compounds are described. The VHAs were prepared by condensation of the appropriate N-substituted hydroxylamine with any of the three reagents: a 1,3-dicarbonyl compound (method A); a vinylogous amide (method B); or an alkynone (method C). The VHAs exist as one or more tautomers in solution with the relative proportions of each being dependent upon the structure of the VHA, solvent, and pH. VHAs undergo some of the typical reactions of hydroxamic acids as well as those of vinylogous amides. VHAs are active as inhibitors of 5-lipoxygenase and of IL-1 biosynthesis in vitro, which do not inhibit other enzymes of the arachidonic acid cascade. They have been shown by ESR studies to bring about inhibition of soybean type 1 15-lipoxygenase by reduction of the active site iron.

Animals↗
PubMed1992

Novel 1-(pyridylphenyl)-1-phenyl-2-imidazolylethanols with topical antiinflammatory activity.

The synthesis, biological evaluation, and structure-activity relationships of a series of 1-(pyridylphenyl)-1-phenyl-2-imidazolylethanols are described. These compounds show potent dose-dependent topical antiinflammatory activity in murine models of skin inflammation. This effect is likely due to inhibition of cytochrome P450 and consequent reduction in levels of 12R-HETE in the skin. These compounds were examined for their ability to inhibit the oxidative metabolism of arachidonic acid; they specifically inhibit the formation of prostacyclins in mouse macrophages. To study the effects of structure on the in vivo activity, three general features of the molecules were varied: the position of attachment of the pyridine nucleus (A), the second aromatic residue (B), and the nitrogen base on the ethanol chain (C). 1-[4-(4-Pyridyl)phenyl]-1-(4-fluorophenyl)-2- imidazolylethanol (2a, DuP 983) shows a very attractive profile of antiinflammatory activity and has been selected for clinical evaluation as a topical antiinflammatory agent.

Administration, Topical↗
PubMed1992

Clinical significance of mucin production in post-irradiated cervical carcinoma.

Histological sections from 50 patients with clinical stage Ib to stage IIb squamous cell carcinoma of the cervix, initially treated by radiotherapy and followed by Wertheim hysterectomy, were reviewed and stained for mucin. The tissues from 17 (34%) of the patients contained no residual carcinoma. Mucin production was demonstrated in tumour tissue from 18 (55%) of the patients with residual tumour, none of who died of disease during the 5 to 10 years of follow up. Two patients who died of recurrent carcinoma had no mucin production in the post-irradiated tumour tissues. The presence of mucin in irradiated carcinoma of cervix seems to infer a better prognosis and this may prove useful in the follow-up of irradiated carcinomas.

Adult↗
PubMed1992

Human papillomavirus and its prognostic significance in invasive carcinoma of the cervix in young patients.

Of 1,200 Chinese patients treated for carcinoma of the cervix between 1975 and 1984, those aged 40 years (n = 70) or less had a poorer prognosis. Of the latter group, 71% had disease classified as less than International Federation of Gynecology and Obstetrics (FIGO) stage Ib, and in 91% the disease was less than stage IIa; however, the 5-year survival of the 45 patients with verified invasive carcinoma was 75% compared with 82% for the overall group. The polymerase chain reaction (PCR) was used to test for the presence of human papilloma virus (HPV) types 16 and 18 within paraffin-embedded tissue from the primary tumors. HPV-16 DNA sequences were detected in 69% of the cases, HPV-18 DNA sequences in 44%, and in 31% both HPV-16 and -18 DNA could be identified. Of the cases of invasive carcinoma, 82% (37 of 45) contained DNA of HPV types 16 and/or 18. The effects of the presence or absence of HPV DNA on known prognostic factors was investigated. Although the influence of traditional factors, especially lymph node involvement, was confirmed, careful statistical analysis could not demonstrate a prognostic influence for HPV-16/18.

Adult↗
PubMed1991

Prognostic importance of cellular DNA content in head-and-neck squamous-cell cancers. A comparison of retrospective and prospective series.

Flow cytometric DNA-ploidy measurements were performed on formalin-fixed tumour specimens from 172 patients with squamous-cell cancers (SCCs) of the head and neck region. One hundred and two samples were chosen retrospectively and a further 70 consecutive patients were analysed prospectively in order to assess the prognostic significance of DNA ploidy and DNA index (DI). There were no statistically significant differences between retrospective and prospective groups in regard to age, sex, TNM stage, ploidy or DI. Sixty-seven percent of patients were aneuploid (65% retrospective; 71% prospective). The proportion of aneuploid tumours was significantly higher among poorly differentiated tumours. Survival analysis using Cox multivariate regression modelling revealed that DNA aneuploidy and increasing DI were significant independent prognostic factors for both relapse-free and overall survival. The relapse and death rates among aneuploid subjects were approximately 3 times as high as those for diploid subjects. Patients with a DI greater than 2.11 (hypertetraploidy) experienced a 6.6-fold higher death rate than diploid subjects. These results provide strong support for the incorporation of DNA ploidy profiles into the clinical management of patients with head and neck cancer.

Adult↗
PubMed1991

Primary mixed neuroendocrine and mucinous carcinoma of the ovary.

A rare case of mixed carcinoma of ovary with a predominant malignant neuroendocrine and a lesser mucinous tumor component is described. Extensive areas of enteric-type epithelium containing endocrine cells were present in both the mucinous borderline tumor element and in the small foci of mucinous adenocarcinoma. Transition from the mucinous tumor to the malignant neuroendocrine component provides evidence for the derivation of some neuroendocrine or carcinoid tumors direct from mucinous tumors without necessarily being a component of a teratoma. Contrary to reported examples of mucinous carcinoid, the overgrowth and spread of the neuroendocrine component characterised the aggressive and lethal nature of this tumor.

Adenocarcinoma, Mucinous↗
PubMed1991

Prevalence of low and high risk human papillomavirus types in cervical cells from Hong Kong pregnant Chinese using filter in situ hybridization.

Filter in situ hybridization, using separate probes for human papillomavirus deoxyribonucleic acid types 6, 11, 16 and 18, was used to determine the prevailing HPV types amongst a group of pregnant Chinese women. This group had been previously identified using a mixture of probes for HPV types 6, 11, 16, 18, 31, 33, 35 (Virapap). Specimens from six of the eleven cases contained one HPV type (55%) while five were positive for two types (45%). The "low-risk" types (HBV6, 11) were identified as frequently as the "high-risk" types (HPV16, 18) in this study.

Cross-Sectional Studies↗