Effects of retinoic acid and fenretinide on the c-erbB-2 expression, growth and cisplatin sensitivity of breast cancer cells.

We investigated the effects of all-trans retinoic acid (ATRA) and fenretinide (4-HPR) on c-erbB-2 expression in SK-BR-3, BT-474 and MCF-7 breast cancer cells and on the growth, differentiation, apoptosis and cisplatin (CDDP) sensitivity of SK-BR-3 cells. It has been reported that oestrogen inhibits c-erbB-2 in oestrogen receptor-positive breast cancer cells. Using ELISA, Western and Northern analysis we have demonstrated that ATRA and 4-HPR exert similar effects down-regulating c-erbB-2 protein and mRNA in c-erbB-2-overexpressing SK-BR-3 and BT-474 and in normally expressing MCF-7 cells. Both retinoids inhibit SK-BR-3 cell growth. ATRA induces cellular enlargement and flattening, suggesting epithelial differentiation. 4-HPR causes nuclear and cytoplasmic condensation, DNA fragmentation and externalization of phosphatidylserine, indicating apoptosis. c-erbB-2 expression/activity has been linked to sensitivity against CDDP. Therefore, combinations of ATRA or 4-HPR with CDDP were tested for their anti-proliferative activity. Retinoid-conditioned cells were either exposed to retinoid and CDDP (schedule I, ''continuous retinoid treatment'') or to CDDP alone (schedule II, ''retinoid pretreatment''). This retinoid-conditioning followed by CDDP +/- retinoid yields stronger growth inhibition compared with unconditioned cells, which were exposed to CDDP +/- retinoid (schedule III, ''no retinoid pretreatment''). The inefficacy of schedule III indicates that retinoid-conditioning is essential for the improvement of the antiproliferative effect. The interactions in schedules I and II are synergistic for ATRA and CDDP, but slightly antagonistic for 4-HPR and CDDR However, 4-HPR + CDDP is more effective in growth inhibition than each drug alone.     

Activation of retinoic acid receptor alpha is sufficient for full induction of retinoid responses in SK-BR-3 and T47D human breast cancer cells

Retinoid signaling via retinoic acid (RA) and retinoid X receptors (RARs and RXRs) regulates mammary epithelial cell growth and differentiation. Loss of RAR-beta might represent an early event during breast carcinogenesis. Higher differentiated, estrogen-dependent, estrogen receptor (ER)-positive (ER+) mammary carcinoma cells have been found to contain relatively high levels of RAR-alpha and to be responsive to retinoids, whereas most undifferentiated, estrogen-independent, ER-negative (ER-) cells are characterized by low RAR-alpha expression and by retinoid resistance. In contrast, RAR-gamma is detectable at equal levels in both ER+ and ER- cells. In the present investigation, we directly examined the relative contribution of the distinct retinoid receptors to the retinoid response of breast cancer cells by comparing the effects of low concentrations of specific retinoids, which selectively activate individual receptor subtypes, on growth, cell cycle distribution, apoptosis, and on the autoregulation of RAR-alpha and RAR-gamma in ER- SK-BR-3 and ER+ T47D breast cancer cells. In vitro growth activity was determined by using a colorimetric cell viability assay and analysis of cell cycle distribution, and apoptosis was performed by flow cytometry of propidium iodide-stained or fluorescent Annexin V-labeled cells, respectively, whereas expression of RAR-alpha and RAR-gamma was determined by Northern blotting. Both cell lines are retinoid sensitive and express high amounts of RAR-alpha, RAR-gamma, and RXR-alpha. RAR-alpha-selective compounds (AM80 and AM580) inhibit cell growth, induce G1 arrest, stimulate apoptosis, and up-regulate RAR-alpha and RAR-gamma mRNA as efficiently as RAR/RXR-pan-reactive (9-cis RA) and RAR-pan-reactive retinoids (all-trans RA, TTNPB). Remarkably, an RAR-alpha antagonist (Ro 41-5253) not only blocks the RAR-alpha-selective agonists but also the pan-reactive compounds. In contrast, RAR-13-selective (CD417), RAR-gamma-selective (CD437/AHPN), and RXR-alpha-selective (Ro 25-7386) retinoids exert no effects on the examined parameters. Thus, our results support the idea that RAR-alpha is the crucial receptor mediating the biological effects during retinoid signaling in both ER- SK-BR-3 and ER+ T47D human breast cancer cells.     

When should cranial magnetic resonance imaging be used in girls with early sexual development?

OBJECTIVE: To determine whether concise parameters can be established in girls who present with signs of early puberty before the age of 8 years, which would help to identify those in whom cranial magnetic resonance imaging (MRI) is indicated. METHODS: A retrospective chart review was undertaken over a 10-year period from 1992-2002. The two requirements for inclusion in this study were girls who manifested pubertal changes before the age of 8.0 years and who underwent MRI of the brain. The records of 130 female patients with the presumptive diagnosis of precocious puberty (PP) were evaluated. Patients' medical records were reviewed for histories of any reported focal neurological complaint suspicious for intracranial lesions, such as headaches, seizures, or visual disturbances, as well as menses and advanced bone age (>2 SD) compared to chronological age. Seventy-five patients met these criteria and were divided into two groups. Group I consisted of nine patients with abnormal cranial MRI; Group II consisted of 66 patients with normal MRI. RESULTS: The patients in each group who had one or more of the central nervous system (CNS) signs and symptoms of early sexual development that were evaluated were markedly different. In Group I, 89% (CI 52-99.7%) had positive signs and symptoms that were suspicious for an intracranial lesion. In Group II, 94% (CI 85-98%), 63 of 66 girls, had no CNS signs or symptoms. CONCLUSION: The use of cranial MRI in the evaluation of girls with early sexual development is excessive. Girls with signs of pubertal development before age 8 years should be evaluated and followed. Those with specific CNS signs and symptoms, menses, and girls with a rapid advance in sexual development should undergo cranial MRI. Using this approach, far fewer patients in our study would have had cranial MRI.     

Monitoring bacterial resistance to restricted antibiotics.

Data on patterns of resistance of eight strains of bacteria toward various restricted antibiotics were collected from 18 public health laboratories in Czechoslovakia. Development of bacterial resistance to gentamicin and colistin did not appear to follow the resistance patterns of bacteria toward more commonly used antibiotics, but there did appear to be a tendency of mutual coresistance to those two drugs in E. coli and Pseudomonas strains. Similarly, oxacillin coresistance was found in lincomycin-resistant staphylococcal strains. Computer-assisted analysis of resistant bacterial strains revealed otherwise-hidden tendencies and mutual relationships among drugs newly marketed in Czechoslovakia.     

Analysis of factors influencing clonogenic growth in vitro of cells from ovarian carcinoma patients

Clonogenic growth (defined as the formation of ≥ 5 colonies per 5 × 10⁵ viable nucleated cells per plate) of ovarian cancer specimens assessed in our clonogenic assay system was significantly associated with the proportion of tumor cells in the suspensions plated (N = 87; P = 0.0006), although there was no quantitative relationship with the corresponding plating efficiencies. An inverse correlation was observed between monocytes/macrophages/mesothelial cells (M) proportion and clonogenic growth (P = 0.013). These associations were most evident when only effusions were considered. Univariate analyses identified tumor cell content, M proportion and, to a lesser degree, granulocyte content as the only factors out of 12 examined to be correlated with colony formation. Multivariate analysis using a logistic regression model identified the proportion of tumor cells as the only significant factor predicting clonogenic growth in vitro (P = 0.0006). The overall accuracy of prediction for growth or non-growth was 63.2%.     

Vascularization of the cervical trachea and its clinical relevance. A scanning electron microscopy study on corrosion casts

The angioarchitecture of the cervical trachea of the rat as a model was studied using scanning electron microscopy of vascular corrosion casts. Four different types of vascular pattern are described. 1. Supplying and draining vessels of the first order (Superior and inferior thyroid arteries, and inferior thyroid veins) situated within the peritracheal tissue at the lateral sides of the trachea. 2. The vessels arising from them, which have a horizontal course and lie within the intercartilaginous membrane (vessels of the second order). 3. The vessels of the third order branching from those of the second order, perforating the intercartilaginous membrane and again running vertically within the tracheal mucosa. 4. Vessels of the fourth order forming the capillary plexus of the tracheal mucosa, consisting of irregular (pars fibrocartilaginea) or rectangular (pars membranacea) meshes. The clinical relevance of the vascular patterns of the trachea is discussed in respect to ischemic tracheal lesions.