Growth inhibition of xenotransplanted human carcinomas by a monoclonal antibody directed against the epidermal growth factor receptor.

In the athymic nude mice model with xenotransplanted human carcinomas, the effect of a monoclonal antibody (MAb 425), directed against the human epidermal growth factor (EGFR), on tumour growth was studied. Five different solid human breast carcinomas and one vulvar epidermoid cancer cell line (A431) were transplanted in nude mice, and treated with MAb 425 2.2 mg intraperitoneally (i.p.) on day 7 post-transplantation. Tumours with EGFR concentrations of > or = 16 fmol/mg soluble cytosolic protein showed growth inhibition, whereas the growth pattern of EGFR-negative tumours was unaffected. Variation of MAb 425 dosage (1.1 versus 2.2 mg) revealed no difference in the growth inhibiting effect. Different application schedules (application on day 0, 12 or 26) showed different onsets and durations of tumour growth inhibition. Repeated application (1.1 mg, day 0 and 12) was followed by a prolonged inhibitory effect. Our results suggest that growth inhibition of EGFR-positive tumours by MAb 425 may lead to an additional treatment option for patients with EGFR-positive cancer.

Proteases associated with gynecological tumors.

Proteases are involved in the invasion and metastasis of tumours by destruction of the basal membrane and connective tissue. As levels in malignant tissue have both prognostic and therapeutic implications, we examined 318 frozen samples from malignant tumours and comparable non-malignant tissue looking for urokinase plasminogen activator (uPA), tissue plasminogen activator (tPA), and plasminogen activator inhibitor-1 (PAI-1) levels with ELISA, as well as cathepsin D with RIA. Oestrogen receptor (ER) levels, progesterone receptor (PrgR) levels and epidermal growth factor receptors (EGFR) were measured by biochemical methods at the same time. Significantly raised levels of uPA, PAI-1 and cathepsin D were found in malignant tissue, with PAI-1 particularly high in carcinoma of the cervix. Significantly raised tPA levels were found in breast cancer tissue with a more favourable clinical prognosis, with a positive correlation between tPA and ER. No correlation could be shown between uPA, PAI-1 and cathepsin D with other prognostic factors for breast cancer. It could be that routine, uncomplicated estimation of tumour-associated proteases such as uPA, tPA, PAI-1 and cathepsin D will provide an independent prognostic marker for therapeutic decisions with regard to gynaecological tumours and breast cancer.

Immuno-biochemical assay for determination of nuclear steroid receptors during tamoxifen therapy.

The exact knowledge of hormone receptor status is critical for therapeutic strategies in hormone-dependent tumors. The influence of tamoxifen on estrogen receptor concentration has to be taken into account when evaluating results in tamoxifen-treated patients. We studied the receptor modulation of tumors xenotransplanted into nude mice (one breast and one endometrial carcinoma) after injection of 50 micrograms tamoxifen/mouse. To differentiate between unoccupied and occupied receptors, determinations were done by an enzyme immunoassay for the estrogen receptor under low- and high-salt extraction. With low-salt extraction we found a temporary decrease of the estrogen receptor concentration within the first hours after tamoxifen treatment. This decrease lasted for several days before recovery to pretreatment levels occurred. The hormone-receptor complexes, tightly bound to acceptor sites of the DNA, increased more than 15 times within 24 h. These values remained at increased levels for 2-7 days, after which a decrease to initial level was observed.

Influence of chemotherapy on hormone receptor concentration in a xenotransplanted endometrial cancer.

There is growing evidence that chemotherapy may influence the hormone receptor capacity in human carcinomas. The consideration of this assumption may be of importance for the therapeutic management of tumors with metastatic spread which underwent previous adjuvant chemotherapy. Therefore we investigated the influence of six different kinds of chemotherapy on the hormone receptor concentration and the percentage of receptor positive cells in xenotransplanted endometrial cancer. Our results can be summarized as follows: (1) We find neither a significant decrease in hormone receptor capacity after chemotherapeutic treatment (biochemical determination), nor do we see a decrease in the percentage of ER/PR pos. cells (immunohistochemistry). (2) On the other hand, there is no increase in hormone receptor concentration inducible by chemotherapy and no increase in ER/PR pos. cells immunohistochemically.

Lymphocyte subsets in patients with ovarian and breast cancer.

Peripheral blood lymphocytes (PBL) from patients with ovarian or breast cancer or benign lesions of the breast, respectively, have been analysed for expression of phenotypic and activation markers by flow cytometry. The results were compared with those of a control group of healthy women. The relative proportion as well as the absolute counts of B lymphocytes were similar in both groups and in the control group. The absolute number of T cells was decreased in breast cancer patients (p < 0.05). The CD4+/CD8+ ratio was significantly depressed in ovarian cancer patients (p < 0.05), but not in breast cancer patients. In the ovarian cancer group, the percentage of CD3+ T cells expressing HLA-DR (p < 0.05) as well as CD3+ T cells expressing CD16 and CD56 (p < 0.05) was significantly higher. The relative proportion as well as the absolute counts of CD3+ T cells expressing the IL-2 receptor (CD25) were significantly higher (p < 0.001), respectively, in breast cancer patients (p < 0.05). These results suggest that gynaecological cancer is associated with specific alterations in the T cell population.

[Does maximum short-term electric stimulation cause contraction of the pelvic floor muscles?]. / Zpusobuje krátkodobá maximální elektrická stimulace kontrakci svalu pánevního dna?

Electric stimulation is successfully used in the treatment of the stress and urgent type of incontinence. Electric stimulation of the muscles of the pelvic floor causes reflex contraction of the striated peri- and paraurethral muscles and is associated with concurrent reflex inhibition of the detrusor muscle. The therapeutic results depends greatly on the total or at least partially preserved innervation of the muscles of the pelvic floor by the pudendal nerve. One of the possible stimuli of the pelvic floor muscles is maximal electric stimulation (MES) and the objective of our study was to evaluate the effect of MES on the muscles of the pelvic floor or to detect possible changes by US and urodynamic examination. The study comprised women with the stress type of incontinence (GSI). The group was formed by 40 women with GSI, 20 were subjected to US examination and urodynamic examination (n = 20). The group of subjects subjected to urodynamic examination was extended to 40 (n = 40). For electrostimulation a Conmax apparatus was used. The applied frequency was 20 Hz, the amplitude from 0 to 90 mA (grades 0.6), pulse duration 0.75 ms. During the cystometric examination the authors recorded a significant increase of the maximal urethral closure pressure (MUCP), prolongation of the functional (FUL) and anatomical length (AUL) of the urethra during MES. During US examination the authors recorded a significant diminution of the gamma angle, a reduction of the mobility of the UV junction and prolongation of the anatomical length of the urethra during MES. From the investigation ensues that the pelvic floor muscles are contracted during MES and those changes contribute to an increase of the muscular tonus and contracting capacity of the muscles of the pelvic floor and thus cause among other things elevation of the neck of the urinary bladder. The elevation contributes to the normalization of the intraabdominal transmission of pressure to the proximal urethra and thus to treatment of the stress type of urinary incontinence.

[Heroin abuse and methadone substitution in pregnancy]. / Heroinabusus und Methadon-Substitution in der Schwangerschaft.

The pre- and postnatal data of 20 pregnant heroin addicts and their neonates are described. 16 women were treated with methadone to prevent withdrawal symptoms. A relatively stabile prenatal condition with a decrease of complications was achieved. On the other hand, the neonates suffered from severe withdrawal symptoms including seizures in spite of intensive paediatric care and prophylactic treatment with barbiturates. After a mean follow-up of one to two years a relatively good neurological development of the children was observed.

[Hormone receptor contents and tumor growth in a series of transplantable human breast carcinoma during and after radiotherapy]. / Hormonrezeptorgehalt und Wachstumsverhalten eines in Serie transplantierten menschlichen Mammakarzinoms unter und nach radiologischer Therapie.

The influence of radiotherapy on tumor growth and hormone receptor concentration (estrogen-, progesteron-receptor) in xenotransplanted human breast cancer is observed. Tumor growth significantly is delayed under therapy during the first 35 days after radiation. Renewed growth follows after that time. After the first days of treatment the ER and PR concentration decreases considerably and finally reaches 40% respectively 30% of the pretreatment level for a period of approximately 35 days after the end of radiotherapy. In general radiation therapy seems to affect the PR stronger than the ER. After this period ER and PR levels increase again with the regrowing tumor. The results point out that radiotherapy reduces the concentration of ER and PR in human breast cancer. Therefore the assay of steroid receptors in human breast cancer after radiation therapy is useful in predicting hormone dependency and prognosis only when receptor concentrations are positive.

Immunobiochemical assay for determination of nuclear steroid receptors.

Knowledge of receptor status is important for therapeutic strategies in hormone-dependent tumors. Therefore, methods specifically predicting biological response to endocrine therapy are essential. We investigated the receptor modulation of two breast tumors and one endometrial tumor in the nude mice model after injection of 20 micrograms 17 beta-estradiol. To differentiate the unoccupied and the occupied receptor sites, we used the enzyme immunoassay (EIA) for estrogen receptors (ER) under low- and high-salt conditions. With low-salt extraction we found a sharp decrease of the ER-EIA values within the first hour after estradiol treatment. This decrease continued for 24 hr until recovery to pretreatment levels occurred. In contrast, the ligand-receptor complexes tightly bound to acceptor sites on the DNA increased more than three times within 1 hr. These high levels could be measured for almost 12 hr, and then pretreatment levels were reestablished. The PgR-EIA values under low-salt conditions increased 10-fold within 12 hr, indicating an intact receptor mechanism. We conclude that this immunobiochemical method is a useful tool in determining receptor sites: those both unbound and those tightly bound to nuclear acceptors.