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Biomedical subjects

A Dalen

Publications and source records attributed to A Dalen.

At least 37 records · Page 2Linked to original sources
PubMed1990

Should asymptomatic patients be tested for Chlamydia trachomatis in general practice?

Routine testing for Chlamydia trachomatis during gynaecological examinations has been suggested as a preventive measure against pelvic inflammatory disease and other health risks associated with chlamydial genital infections. This study examined the cost and effectiveness of routine testing for C trachomatis in general practice. An epidemiological model was used to predict how routine testing and treatment of positive cases would affect the future number of cases of pelvic inflammatory disease, infertility and ectopic pregnancy in a general practice population. The cost of routine test and treatment, and savings resulting from prevented future morbidity, were also estimated. For the population under study, a routine test for chlamydial infections in asymptomatic 18-24 year old women during gynaecological examinations was found to be cost effective but this was not the case for older women. At least two years should elapse between repeated tests.

Adolescent↗
PubMed1989

[Chlamydia trachomatis and ectopic pregnancy. A causal relationship].

In a case-control study, chlamydial antibody (IgG) was examined in sera from 58 women with ectopic pregnancy and 58 birth-giving controls matched for age (+/- 3 years) and parity. More patients than controls stated that they had previously been treated for salpingitis (p less than 0.05). In the index pregnancy, two cases and four controls were positive for C trachomatis in specimen from the cervix uteri. Chlamydial antibody was detected among 69% of the cases and 33% of the controls (p less than 0.01). These results were consistent with age, parity and information on previous treatment for salpingitis. The occurrence of a previous chlamydial infection, proven by IgG-antibodies, increases risk of an ectopic pregnancy by a factor of 4.6 (odds ratio 4.6, 95% CI 2.1-10.3).

Adolescent↗
PubMed1989

[Chlamydia trachomatis and infertility in women].

Humoral IgG antibodies to Chlamydia trachomatis were determined in 131 infertile women, 102 with fallopian tube disorders and 29 with other infertility diagnosis and normal fallopian tubes. Chlamydia antibodies were identified significantly more often among women with abnormal fallopian tubes (89%) than among women with other infertility diagnosis (48%). Among Chlamydia antibody positive subjects the mean index was significantly higher among subjects with tubal disorders than among subjects with normal tubes (3,4 versus 2,2; p less than 0.01). This study indicates a close association between anti-bodies to Chlamydia trachomatis and tubal infertility.

Adult↗
PubMed1989

Overexpression of the epidermal growth factor receptor gene in a human carcinoma cell line, derived from a brain metastasis.

Abnormally high expression of epidermal growth factor receptors (EGF-receptors) may contribute to the unregulated growth of some tumors. We here report the EGF-receptor numbers and the effects of epidermal growth factor (EGF) on two human cell lines. The glioblastoma cell line T-MG1 had 135,000 EGF-receptors per cell, was slightly growth stimulated by EGF and showed no obvious change in morphology after exposure to EGF. The carcinoma cell line T-CAR1, derived from a brain metastasis of a carcinoma of the adrenal cortex, had approximately 7 million EGF-receptors per cell. EGF had a significant antiproliferative effect on these cells and caused rounding and detachment of cells in adherent cultures. The cell lines may become useful in future studies concerning the role of the EGF-receptors in malignant growth.

Brain Neoplasms↗
PubMed1989

Cost effectiveness of testing for chlamydial infections in asymptomatic women.

Routine testing for Chlamydia trachomatis during gynecological visits, as well as treatment of those found positive, has been suggested as a preventive measure against the serious consequences of chlamydial genital infections, e.g., pelvic inflammatory disease (PID), infertility, and ectopic pregnancy. This article examines the cost and effectiveness of this practice. The study is based on a model that predicts how routine testing and treatment will affect the future number of cases of PID, infertility, and ectopic pregnancy. The costs of test and treatment are estimated, as are the savings resulting from prevention. Results indicate that although routine testing was not effective in reducing the overall morbidity caused by chlamydial infections, for women 18-22 years of age routine testing during regular gynecologic sessions can be a cost-effective personal health service.

Adolescent↗
PubMed1989

Effects of interferon-gamma and tumor necrosis factor-alpha on clonogenic growth of cell lines and primary cultures from human gliomas and brain metastases.

In this study we tested the effect of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and a combination of these immunotherapeutics on clonogenic growth of cell lines and primary cultures of malignant human brain tumors. Out of 29 primary cultures studied, 5 were inhibited 50% or more by IFN-gamma (10 ng/ml), 6 were inhibited 50% or more by TNF-alpha (10 ng/ml) and 14 were inhibited 50% or more by a combination of IFN-gamma (10 ng/ml) and TNF-alpha (10 ng/ml). The doses of the immunotherapeutics used in this in vitro study are achievable in serum after intravenous administration of IFN-gamma and TNF-alpha without causing unacceptable side effects. We believe that some glioma patients and some patients with brain metastases will benefit from receiving treatment with IFN-gamma, TNF-alpha or a combination of these immunotherapeutics. The patients should be selected for treatment with these immunotherapeutics according to in vitro sensitivity results.

Cell Division↗
PubMed1989

Genital Chlamydia trachomatis infections in patients with abnormal cervical smears: effect of tetracycline treatment on cell changes.

A group of 1760 women aged 14-35 years were examined for the concurrent presence of Chlamydia trachomatis and cellular atypia of cervical smears. Positive tests for C trachomatis were found in 126 women (7.2%). Cell changes were found in 85 women (4.8%), and 25 of these were C trachomatis-positive. Slight cellular atypia was the major finding in the smears from 22 of the C trachomatis-positive women, whereas three patients had more pronounced cell changes. Smears reverted to normal in 18 of the 23 patients who returned for tetracycline treatment and follow-up cytology. All 18 patients had smears showing slight cellular atypia prior to therapy. In five patients who also had cellular changes suggesting a human papillomavirus infection, the smears did not revert to normal after antibiotic therapy during the observation period. These findings suggest that patients with C trachomatis and mild cellular atypia should have antibiotic therapy and repeat smears taken before further treatment is considered. More advanced cellular atypia is unlikely to be caused by C trachomatis.

Adolescent↗
PubMed1988

The effect of type beta transforming growth factor on proliferation of clonogenic cells from human gliomas.

Type beta transforming growth factor (B-TGF) is a potent regulator of cell growth and differentiation. Growth of many human tumour cell lines are inhibited by B-TGF. The effect of B-TGF on proliferation of clonogenic cells from 12 human glioma biopsies was registrated in a thymidine incorporation assay. B-TGF appeared to be a potent growth inhibitor for some gliomas, while it had no effect on others. Maximum inhibition was about 60%. Though not significant, glioblastomas appeared to be less sensitive to inhibition by B-TGF than astrocytomas and oligodendrogliomas. Very little is known about the growth inhibitory action of B-TGF. The negative autocrine growth theory for cancer cells postulates that a reduced production, or production of a defective growth inhibitor normally found in the cell, may account for the autonomous nature of some cancer cells. In view of this theory, we searched for B-TGF in protein extracts from a glioblastoma cell line, T-MGl, whose growth was inhibited by B-TGF. Protein extract from T-MGl cells was analysed for B-TGF activity using a soft agar colony formation assay with normal rat kidney fibroblasts. B-TGF was not found in the extract. Since, according to the literature B-TGF has been found in all other cell lines examined, we believe that there may be a lack of B-TGF or an altered B-TGF in the gliomas whose growth are inhibited by B-TGF. This problem will be studied further.

Brain Neoplasms↗
PubMed1988

The effects of type beta transforming growth factor on proliferation and epidermal growth factor receptor expression in a human glioblastoma cell line.

Type beta transforming growth factor (B-TGF) is a potent growth inhibitor to many human tumor cell lines. Very little is known about the mechanism for this growth inhibitory action of B-TGF. We here report the effect of B-TGF on proliferation and epidermal growth factor receptor (R-EGF) expression in a human glioblastoma cell line named T-MG1. B-TGF inhibit the soft agar growth of T-MG1 cells. Maximum inhibition was 70%, achieved with 0.5 units B-TGF. B-TGF had no effect on monolayer growth of T-MG1 cells. T-MG1 cells contained abundant R-EGF, which could be divided into two subpopulations, one high affinity and one low affinity population of R-EGF. Treatment with B-TGF caused an initial decrease (0-6 h) in EGF-binding, followed by an increase in EGF-binding which reached maximum after 24 h exposure to B-TGF. Since addition of EGF to agar cultures gave no additional increase in inhibition by B-TGF and EGF alone had no inhibitory effect, we believe that binding of EGF to its receptor is not part of the pathway mediating the inhibitory effect of B-TGF. All neoplastic cells have lost some measure of growth control and the cellular elements involved are growth factors, growth factor receptors and oncogenes. T-MG1 cells contain abundant R-EGF and this may partly explain their malignant nature (malignant nature is here defined as ability to proliferate in agarose). Type alpha transforming growth factors, which in some cancer cells act as uncontrolled autocrine growth factors, were not found in protein extracts from T-MG1 cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Type beta transforming growth factor and epidermal growth factor suppress the plasminogen activator activity in a human glioblastoma cell line.

In the human glioblastoma cell line, T-MG1, plasminogen activator activity (PA-activity) was demonstrated by using the chromogenic substrate S-2251. Using monoclonal antibodies against human urokinase type PA (u-PA) and human tissue type PA (t-PA), only u-PA activity was found in T-MG1 cell extracts. The u-PA activity in T-MG1 cells was suppressed in a dose-dependent manner by B-TGF and EGF after 24 hours of exposure to these growth factors. Twenty units of B-TGF caused a decrease in PA-activity of 80%, while 10 ng/ml EGF gave a decrease in PA-activity of 60%. The suppressive effects of B-TGF and EGF were observed after 2 hours and 4 hours of incubation, respectively and sustained for at least 24 hours. The effects of B-TGF and EGF were not antienzymatic, but rather mediated through regulatory mechanisms. In view of the capacity of invasive growth of gliomas and the potential role of PA in invasive growth, the suppression of PA-activity in gliomas by B-TGF and EGF may be of importance.

Aged↗
PubMed1988

Effects of type beta transforming growth factor in combination with retinoic acid or tumor necrosis factor on proliferation of a human glioblastoma cell line and clonogenic cells from freshly resected human brain tumors.

Type beta transforming growth factor (beta-TGF) is a potent regulator of cell growth and differentiation. The human glioblastoma cell line, T-MGI, was growth inhibited by beta-TGF under anchorage independent conditions. The antiproliferative effect of beta-TGF was potentiated to nearly total arrest by low doses of retinoic acid (RA) or tumor necrosis factor (TNF), while epidermal growth factor, platelet-derived growth factor, interleukin-2, and gamma interferon did not have this potentiating effect. The potentiation of the beta-TGF effect by RA and TNF could not be explained by modulation of the epidermal growth factor receptor, the beta-TGF receptor, or the TNF receptor. beta-TGF alone and in combination with RA or TNF were further tested on primary cultures from freshly resected human glioma biopsies (n = 13). There was great individual variation in sensitivity to beta-TGF, RA, or TNF. The astrocytoma and oligodendroglioma cells were inhibited to various degrees by beta-TGF or TNF, while most of the glioblastomas were not sensitive to these agents. Most of the biopsies were stimulated by RA. RA or TNF did not potentiate the growth inhibitory effect of beta-TGF on biopsy cells. We therefore think it unlikely that beta-TGF in combination with RA or TNF will be effective agents in the treatment of gliomas.

Adjuvants, Immunologic↗
PubMed1988

An isotope agarose assay for rapid testing of the sensitivity of glioma biopsies to chemotherapeutic drugs and biological response modifiers. Effects of BCNU, vincristine, lymphokines and the recombinant agents interferon alpha 2c, interferon gamma and tumour necrosis factor.

A method based on growth of cells from glioma biopsies in a triple layer agarose system has been used to test the sensitivity of the tumour cells to different chemotherapeutic and immunotherapeutic agents. A special agarose that could be melted at 65 degrees C, enabled registration of proliferation by an easy and precise thymidine incorporation technique. The well known concept that agarose permits proliferation of malignant cells and inhibits growth of benign cells was confirmed in this assay by using the malignant glioma cell lines T-MG 1 and U 251 MG, and the benign glia cells T-BG 2 and T-BG 3. All of the 15 glioma biopsies grew exponentially during the first 7 days. The correlation between thymidine incorporation on day 7 and colony number on day 14 was very good for the glioma cell line (r = 0.96) and also for the glioma biopsies (r = 0.89), indicating that the sensitivity evaluation can be done as early as 7 days after the operation. Lymphokines, made by BCG-stimulated lymphocytes, had a strong inhibitory effect on the growth of some glioma biopsies, while others were only slightly inhibited or even stimulated. There was also a huge variation in the sensitivity of the biopsies to BCNU, but the sensitivity pattern was completely different for BCNU and lymphokines. rIF-A had a moderate inhibitory effect on growth of the biopsies, while rTNF had a weak inhibitory effect. The response to rIF-G varied from stimulation of some biopsies to strong inhibition of others. There was no similarity in the sensitivity pattern of the biopsies to rIF-A and rIF-G.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Transforming growth factor-beta 1 is a potent inducer of plasminogen activator inhibitor type-1 in human glioblastoma and carcinoma cell lines.

Transforming growth factor-beta 1 has been shown to suppress the urokinase activity in the glioblastoma cell line T-MG1 and the carcinoma cell line T-CAR1. The molecular mechanisms behind the decrease in the proteolyic activity is shown to be at least partly due to increased synthesis of plasminogen activator inhibitor type-1 and not by decreased synthesis of urokinase.

Blotting, Northern↗
PubMed1988

Induced abortion: Chlamydia trachomatis and postabortal complications. A cost benefit analysis.

The overall prevalence of Chlamydia trachomatis among 873 abortion-seeking women was 9.3% during 1985. Significantly higher age-specific prevalences of C. trachomatis occurred among younger women (p less than 0.001). None of 17 women treated for C. trachomatis before the abortion was carried out, was readmitted to the hospital. Of 64 Chlamydia-positive women, who commenced treatment within the first 2 weeks after the abortion was carried out, 14.1% were readmitted to the hospital, compared with 5.7% of Chlamydia-negative women (p less than 0.02). Postabortal salpingitis was verified at readmission among 10.9% of Chlamydia-positive women and 3.2% of Chlamydia-negative women (p less than 0.01). An analysis of screening of all abortion-seeking women is estimated to be worthwhile when the prevalence of C. trachomatis exceeds 4.3%. We recommend screening for Chlamydia trachomatis of all abortion-seeking women, 30 years or younger, at the pre-abortion visit, provided that treatment can be completed before the abortion is carried out.

Abortion, Induced↗
PubMed1988

Amplification of the epidermal growth factor receptor gene in biopsy specimens from human intracranial tumours.

Amplification and overexpression of proto-oncogenes are associated with the malignant nature of some human tumours. In this study we have determined the prevalence of amplification of the proto-oncogenes c-erb B1 (= epidermal growth factor receptor gene), c-erb B2 and c-myc in 44 human intracranial tumours (27 gliomas, six metastases to the brain and 11 meningiomas). None of the tumours had an amplified c-erb B2 gene and only two tumours had an amplified c-myc gene. Nineteen per cent (five out of 27) of the gliomas, 50% (three out of six) of the brain metastases and 0% (0 out of 11) meningiomas had an amplified EGF-receptor gene. Amplification of the EGF-receptor gene appeared to give a growth advantage when single-cell suspensions of the tumours were grown in agarose.

Adult↗
PubMed1988

Chlamydia trachomatis: is it possible to reduce the number of infections after abortions?

In a study at the University Hospital in Trondheim during 1983, the frequency of Chlamydia trachomatis among women terminating their pregnancies was 8.2%. Younger women were infected by C. trachomatis at a more frequent rate than older women (p less than 0.001). Treatment of chlamydia-positive women was initiated within the first two weeks after the abortion. However, among women readmitted to the hospital, chlamydia-positive women showed a higher frequency of salpingitis than chlamydia-negative women (p less than 0.08). Preabortion examination for C. trachomatis and treatment of chlamydia-positive women by practitioners before the abortion is carried out, may reduce the postabortal frequency of salpingitis.

Abortion, Induced↗