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Biomedical subjects

G Birmelin

Publications and source records attributed to G Birmelin.

12 recordsLinked to original sources
PubMed1997

[Contrast media in MR mammography].

A standardized relationship between concentration of contrast media and normalized signal intensity should be the basis of a diagnostic evaluation of MR-mammography at different sites and with different sequences. In this work we compared the dynamic range of the MR-compatible contrast medium Magnevist at different sequences and machines. For this purpose we made measurements with a phantom, consisting of MR-compatible glass tubes filled with contrast medium of different concentrations. The glass tubes were placed in a water bath. All measurements were made with breast coils. The signal intensity of the glass tubes was normalized to the signal intensity of the native probe (water = 1). These normalized dynamic curves were compared with each other in order to find, for the different machines, the sequence which is nearest to a defined "Standard-Curve". As this task proved not possible for all machines, we measured how the dynamic curves of the different machines related to the "Standard-Curve". For all sequences we made also measurements with a female student to assure the quality of the pictures. Thus the participating radiologists can now compare their dynamic measurements of breast lesions with each other.

Breast↗
PubMed1993

Gene structure and expression analysis of the epidermal growth factor receptor, transforming growth factor-alpha, myc, jun, and metallothionein in human ovarian carcinomas. Classification of malignant phenotypes.

This study reports the structure and expression rates of genes of the transforming growth factor-alpha (TGF-alpha) signal transduction pathway (TGF-alpha, epidermal growth factor receptor [EGF-R], jun, myc, and metallothionein [MT]) in 47 specimens of ovarian cancer and 21 nonmalignant tissues. The objective was to establish a direct correlation between the genetic activities and the malignant phenotype of the ovarian cancer. The Southern blot technique identified four samples with myc amplification and two with rearranged EGF-R genes. By using the S1 nuclease assay, the analysis of myc transcription showed a similar use of both promotors. Although the size of the investigated transcripts was unaltered, significant differences in the transcription rates were noticed in malignant tissue probes (using northern blot analysis and RNAase protection assay). The following results of messenger RNA analysis in ovarian cancer were observed: EGF-R, negative in 25%, low in 65%, and strongly positive in 10%; TGF-alpha, negative in 34%, low in 36%, and strongly positive in 30%; myc, negative in 8%, low in 64%, and strongly positive in 28%; jun, negative in 4%, low in 58%, and strong in 38%; and MT, low in 80% and strongly positive in 20%. In most nonmalignant tissues studied, no or only a low expression of TGF-alpha, EGF-R, and myc. was found. A comparison of these messenger RNA results with the clinical data from tumors showed four different subgroups of ovarian carcinomas. The results of chemotherapy were known in 32 cases. Tumors with negative or low expression rates of all investigated genes did not respond to chemotherapy; 13 of 18 tumors with high expression rates did respond. Additional signal transduction chains distinct from the TGF-alpha pathway, however, are likely to influence both the expression and activity of transcription factors and MT.

Adult↗
PubMed1992

Epidermal growth factor receptor and transforming growth factor alpha expression in human ovarian carcinomas.

The varying tumorbiological behaviour of ovarian carcinomas probably influences operability, response to chemotherapy, being one of the most relevant prognostic factors. Because it is believed that an activation of the epidermal growth factor/transforming growth factor alpha (EGF/TGF alpha) signal pathway could be involved, we analysed the expression of epidermal growth factor receptor (EGFR) and TGF alpha with molecular-chemical, biochemical and immunohistochemical methods in 42 ovarian carcinomas, 4 ovarian metastasis, 2 other malignant ovarian tumours, and in 25 nonmalignant tissues (ovary, myometrium). No major rearrangements or amplification of the EGFR or TGF alpha genes were found. In non-malignant tissues no strong EGFR or TGF alpha signals were detected. TGF alpha is mainly produced by the tumour cells as shown by immunohistochemistry. Four different high molecular weight forms (20-48 kD) were detected in malignant tissues by western blot analysis.

Blotting, Northern↗
PubMed1992

Oncogene and growth factor expression in ovarian cancer.

The varying tumor-biological behavior of ovarian carcinomas probably influences both their operability and response to chemotherapy, which are the most relevant prognostic factors. The phenotype of different ovarian carcinomas is obviously associated with an activation of the EGF/TGF-alpha signal pathway, including c-myc and c-jun expression. Analysis of EGF-R, TGF-alpha, c-myc and c-jun expression in 33 stage III/IV, and 2 stage I/II ovarian carcinomas with biochemical, molecular-chemical and immunohistochemical methods showed a correlation between the mRNA and protein levels of EGF-R and TGF-alpha for tumors with low or high expressing rates. However, the concentration of measurable free EGF-Rs seems to depend on the amount of TGF-alpha expression by the tumors. The EGF-R binding ligand TGF-alpha is produced by epithelial tumor cells; stromal cells are usually TGF-alpha-negative, as shown by immunohistochemistry. High expression rates of EGF-R. TGF-alpha and c-myc were detected in 6, 7, and 10 out of 35 ovarian carcinomas, respectively. C-jun mRNA was detected in 18/19 cases studied. Non-malignant tissues originating from myometrium or ovary expressed no (or only small amounts of) EGF-R or TGF-alpha mRNA, whereas a high c-myc expression was found in 1/7 normal myometria, and in 2/5 normal ovaries. There was no strong correlation between EGF-R/TGF-alpha and c-myc/c-jun expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Northern↗
PubMed1990

Clinical significance of oncogenes and growth factors in ovarian carcinomas.

The expression of epidermal growth factor receptor (EGF-R), transforming growth factor alpha (TGF alpha) and the c-myc oncogene was investigated in different specimens of gynecologic carcinomas. EGF specific binding sites were detected in about 50% of adenocarcinomas (ovarian, endometrial, breast) and in over 90% of squamous carcinomas (cervical). There is a positive correlation between the EGF-R binding assay, immunohistochemistry and the relative amounts of mRNA by Northern blotting. TGF alpha was investigated by immunohistochemistry and Northern blotting. TGF alpha immunoreactivity was detected exclusively in the epithelial cells of nonmalignant tissues (skin, cervix, endometrium, large bowel, lung) as well as different ovarian carcinomas. The TGF alpha immunostaining score correlates with the TGF alpha mRNA amounts. The c-myc expression was analyzed by Northern blotting in the specimens of ovarian carcinomas. Whereas, a positive correlation between the c-myc and TGF alpha expression was noticed, no correlation existed between EGF-R and c-myc expression. Progressive disease (PD) of ovarian carcinomas after chemotherapy was mainly noticed in the group of EGF-R- tumors and those with high amounts of c-myc mRNA. EGF-R+ ovarian carcinomas responded significantly better to chemotherapy. However, similar survival times existed between the EGF-R+ and EGF-R- group and the survival times of patients having responded to the treatment was reduced in the EGF-R+ group. This indicates that EGF-R+ and those carcinomas expressing high amounts of c-myc constitute a more aggressive group of ovarian carcinomas.

Adenocarcinoma↗
PubMed1990

[Clinical aspects of HPV-16/18 associated cervical lesions].

In 147 patients with suspected dysplasia, the effect of HPV 16/18 infection on the spontaneous course of the cervical intraepithelial neoplasia (CIN) and on the success of conisation and laser treatment was studied. The patients with PAP II smears had a high incidence of HPV (67%). This was accompanied, however, by a high rate of regression and fluctuation of the various virus types. Of the untreated cases of CIN, the lesions associated with HPV 16/18, particularly after repeat virus DNA identification of this type, had a higher persistence rate than HPV 16/18 negative CIN. After local therapy by laser surgery or conisation of HPV 16/18-related CIN, persistent disease must be expected in 30%. CIN recurrence was significantly more frequent in HPV 16/18 positive cases. According to the results of the investigations, HPV typing appears to be a useful tool in deciding on the appropriate therapy only in cases of persistent CIN and in determining an HPV 16/18 positive at-risk group after local (laser/conisation) therapy.

Adolescent↗
PubMed1988

[CO2 laser therapy and typing of human papilloma virus in follow-up studies of cervix intraepithelial neoplasms].

In 104 woman patients with cervical intraepithelial neoplasia (CIN) I-III who had been treated between 1981 and May 1986 in the dysplasia consulting-room of the Department of Gynecology by means of conisation effected by laser, we checked on therapeutic success via cytology and colposcopy as well as by human papilloma virus (HPV) typing. In 90.3% of the cases 1.25 laser treatments sufficed for healing of the lesion. Relapses occurred mainly in severe intraepithelial neoplasias with identified HPV 16/18. Incidence of HPV was reduced from 56% before therapy to 13.3% after therapy. This shows that laser therapy can be regarded as an effective treatment of the causes of the disease even in CIN associated with HPV. The markedly increased relapse rate in CIN III (24%) makes a reliable follow-up mandatory especially in such cases.

Cervix Uteri↗
PubMed1987

Human papillomavirus standardization and DNA cytophotometry in cervical intraepithelial neoplasia.

Human papillomavirus (HPV) standardization and DNA cytophotometry were carried out in 29 cases of cervical intraepithelial neoplasia (CIN) grades I-III. A prognostically unfavorable DNA distribution pattern with an aneuploid stemline was found in 14 of the 16 dysplasias with HPV types 16 and 18, while in 11 of 13 dysplasias with HPV types 6 and 11 there was a favorable DNA distribution with a euploid-polyploid stemline. Among 178 colposcopically, cytologically and histologically confirmed cervical lesions, there was a statistically significant incidence of HPV 16/18 infections in severe dysplasias and carcinomas, while HPV 6/11 was found predominantly in mild cervical lesions. It seems that CIN can be divided into high- and low-risk lesions not only by the degree of severity and the DNA distribution pattern but also by HPV typing.

Adult↗
PubMed1983

[Antibiotic prevention in hysterectomy. Effectivity of a single preoperative ceftriaxon dose].

In a prospective study, 50 women patients were given 2 g Ceftriaxon (Rocephin) as a short infusion before performing hysterectomy. A control group of 50 patients remained without any antibiotic treatment. In 31 patients, the concentration of Ceftriaxon in the serum and tissue was determined at the time the uterus was removed. Due to the long half-life of Ceftriaxon (8 hours), high serum and tissue levels were found for a period of many hours. After 4-5 hours, the serum level was still 100 micrograms/ml, whereas the concentration in the endometrium, myometrium and in the salpinges were 21 micrograms/g, 24 micrograms/g and 31 micrograms/g, respectively. Due to these long-lasting serum and tissue levels, the protective effect against infections was also very high. 15 infections in the control group are contrasted by one infection only in the treated group. The efficacy of the prophylaxis is objectively assessed by measuring the temperature curve and by determining the number and the spectrum of the postoperatively isolated germs. The germs isolated in the treated group are exclusively such germs which are resistant to Ceftriaxon (enterococci) or which are only moderately sensitive to Ceftriaxon, such as Bacteroides.

Adult↗
PubMedDate not supplied

[Experiences with HELLP syndrome].

Between 1988 and 1991 thirty-nine pregnant women suffering from HELLP-Syndrome were treated in our hospital. A retrospective analysis of clinical course and of the changes in the relevant laboratory values was performed. The incidence of the HELLP-Syndrome at Freiburg University Hospital was 0.85% for all pregnancies or 17% of the patients with toxaemia. 90% of the women were primipara, there was no prevalence of a certain group. The clinical course was characterized by the perseverance of symptoms for more than two weeks in 18% of the cases and a perinatal mortality of 25%, the latter mainly due to prematurity of the infants. This suggests that perinatal mortality due to respiratory distress syndrome can be reduced by conservative and expectative management of these patients. However on the other side a high rate of caesarean sections (77%) and sometimes even induced abortions were necessary to avoid maternal mortality and severe pre-or postpartal complications for these women.

Adult↗
PubMedDate not supplied

Expression analysis of EGF-R and TGFa in human ovarian carcinomas.

Differences in the tumor biology of ovarian carcinomas probably influence operability and response to chemotherapy which are the most relevant prognostic factors. The phenotype of different malignant epithelial tumors including ovarian carcinomas is obviously associated with an activation of the EGF/TGFa signal pathway. When we analysed the expression of EGF-R and TGFa with biochemical, molecular-chemical and immunohistochemical methods in 29 different ovarian carcinomas, we found a correlation between the mRNA and protein levels of EGF-R as well as TGFa for tumors with low or high expressing rates. However, the concentration of measurable free EGF-Rs seems to depend on the amount of TGFa expression by the tumors. The EGF-R binding ligand TGFa is produced by the tumor cells; stromal cells are TGFa negative as shown by immunohistochemistry. By the use of an immunostaining index the TGFa protein concentration was measured semiquantitatively, classifying tumors according to their TGFa production rate. The comparison of TGFa mRNA amounts and staining index supports the hypothesis that TGFa is modified posttranslationally. EGF-R or TGFa expressing ovarian carcinomas had a high response rate to chemotherapy, whereas the EGF-R or TGFa negative tumors mostly exhibit a no change or progressive disease behaviour. These findings are the basis for our assumption that ovarian carcinomas with the basis for our assumption that ovarian carcinomas with an activated EGF-TGFa system are tumor biologically different compared to the EGF-R/TGFa negative tumors.

Antineoplastic Combined Chemotherapy Protocols↗