Toward a new method to in situ study of apoptosis and its relations with cell cycle

Apoptosis or programmed cell death plays a key role in many biological processes particularly in oncology. The detection of apoptotic cells is crucial for the study of the phenomenon itself and its relation with the proliferative cell cycle. A new method to detect apoptosis in situ in Feulgen stained cells was developed, based on multiparametric analysis (factorial and decisional analysis), using 15 densitometric and textural parameters measured on a SAMBA 200 cell image processor. Six reference files corresponding to G1, S, and G2 phases and to apoptotic cells derived from these cell cycle phases were constructed. The projection of these files in the factorial principal plane formed distinct clusters. Using the decisional discriminant analysis, it was possible to ascertain the state (apoptosis or proliferative) and the phase for each cell of a population. The correct classification rate of this analysis was 0.9962. Determining the cell cycle phase from which each apoptotic cell comes, we are able to study the relation between apoptosis and the proliferative cell cycle. Moreover, the detection in situ allows us to study cell-cell interactions.

Antiproliferative and receptor binding properties of alpha- and beta-casomorphins in the T47D human breast cancer cell line

In previous studies, we have shown that opioid agonists ([D-Ala2, D-Leu5]enkephalin (DADLE), [D-Ser2, Leu5]enkephalin-Thr6 (DSLET), ethylketocyclazocine and etorphine) bind to opioid binding sites and decrease cell proliferation of human T47D breast cancer cells. Furthermore, we provided evidence about a cross-reaction, also in the T47D human breast cancer cell line, of mu-acting opioids with type-II somatostatin receptors. Since a potential source of opioid activity in the breast might be casomorphin peptides (produced by the enzymatic degradation of alpha-casein and beta-casein), we investigated the antiproliferative action of five different casomorphin peptides: alpha-casein-(90-95), alpha-casein-(90-96), beta-casomorphin, beta-casomorphin-(1-5) and morphiceptin. We show that all five peptides decreased, in a dose-dependent manner, cell proliferation. The general antagonist diprenorphine produced only a partial reversal of their action. Furthermore, we provide evidence that all peptides (except for morphiceptin) bind to delta- and kappa-opioid binding sites of T47D cells with different selectivity. Finally, we show that these peptides are also partial competitors at the somatostatin receptors present in the same cell line.

17 beta-Hydroxysteroid dehydrogenase activity correlates with the type-2 17 beta-hydroxysteroid dehydrogenase mRNA abundance in human meningioma tumors

Benign meningioma tumors possess significant levels of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity. Two different 17 beta-HSDs were discovered in human placenta: one highly estrogen specific and using NADP+/NADPH as cofactors (type-1 17 beta-HSD), and a second one that utilizes both androgens and estrogens as substrates with NAD+/NADH (type-2 17 beta-HSD). Recently, two further human 17 beta-HSDs were isolated. A testis-specific 17 beta-HSD (type-3 17 beta-HSD) favors the reduction of delta 4-androstenedione to testosterone, and a ubiquitously expressed type-4 17 beta-HSD preferentially catalyzes the oxidation of estradiol and delta 5-androstenediol. In this study we characterize the expression levels of different types of 17 beta-HSD in a wide series of tumors. Using the Northern blotting method we show that type-1, -3, and -4 17 beta-HSDs are not detectable in meningiomas. In contrast, the type-2 17 beta-HSD RNA is present in 6 of 17 meningiomas and its abundance is directly correlated with estrogenic 17 beta-HSD activity (r2 = 0.74). The presence of type-2 17 beta-HSD is also demonstrated by in situ hybridization. RT-PCR and Western blots show that type-4 17 beta-HSD is also present, though at much lower levels. The progesterone receptor level, the epidermal growth factor receptor level, and the age of the patients are not correlated with the estrogenic 17 beta-HSD activity or type-2 17 beta-HSD mRNA expression level.

Divergent effect of TGFbeta1 on growth and proteolytic modulation of human prostatic-cancer cell lines

Plasminogen activators (PAs) play a key role in malignant transformation. PA secretion by tumoral cells is strongly correlated with their aggressive phenotype. Regulation of invasive potential by growth factors has been also demonstrated. This study was designed to investigate the effects of 5alpha-dihydrotestosterone (DHT), epidermal growth factor (EGF), transforming growth factor beta1 (TGFbeta1), retinoic acid and basic fibroblastic growth factor (bFGF) on cell growth and PA expression and secretion in DU145 and PC3 cells, 2 human prostatic-cancer cell lines. The proliferation of 2 cell lines was significantly increased only by EGF (about 30%), but decreased by TGFbeta1 (40% inhibition). However, EGF-treated cells showed significant enhancement (about 400%) of u-PA secretion. A similar effect was observed when cells were cultured with DHT (200%) and with TGFbeta1 (300%). Nevertheless, u-PA mRNA level in EGF-, TGFbeta1 - or DHT-treated cells was amplified only between 110 and 180% of control, suggesting that growth factors differently controlled the steps of PA expression. Furthermore, our results clearly showed the divergent effect of TGFbeta1, i.e., an inhibition of prostatic-cell-line growth accompanied by an increase in proteolytic activity.

Differential activation of microglia and astrocytes following trimethyl tin-induced neurodegeneration

We have investigated the response of astrocytes and microglia to trimethyl tin intoxication in the septum, hippocampus, olfactory bulb, and pyriform cortex of the rat. Microglia were studied qualitatively using lectin histochemistry, and astrocytes were examined both qualitatively with immunohistochemistry, and quantitatively using an immunoassay for glial fibrillary acidic protein. Our results show that activated microglia first appeared 2 days after trimethyl tin intoxication in the lateral septum and hippocampus. Four days after trimethyl tin intoxication, the same regions revealed a most intense microglial reaction characterized by microglial hypertrophy and the formation of phagocytic clusters. By day 7, microglial activation in the septum and hippocampus had lessened, suggesting that the cells were reverting to the resting phenotype. The microglial response in the pyriform cortex and olfactory bulb, while being later in onset than in the septum and hippocampus, showed a similar progression of microglial changes reaching maximal intensity 7 days after trimethyl tin intoxication. Significant increases in the expression of glial fibrillary acidic protein were observed in all regions examined and typically occurred after microglial activation was already underway. We conclude that microglial and astroglial reactions which occur in response to trimethyl tin-induced neuronal necrosis are separated in time, with microglial activation preceding astrogliosis. In addition, our study stresses the importance of microglia as an endogenous source of CNS macrophages, and illustrates the merit of histochemical analysis with microglial markers for the early delineation of neurotoxicant-induced brain damage.

Regulation of p42 mitogen-activated-protein kinase activity by protein phosphatase 2A under conditions of growth inhibition by epidermal growth factor in A431 cells

Epidermal growth factor (EGF), which plays an important role in the growth regulation of a large variety of normal and tumor cells, has been shown to display an ambivalent dose-dependent effect on the proliferation of epithelial cells overexpressing EGF receptor. In a previous study aimed at dissecting the biochemical events leading to this dual action in A431 cells which over express EGF receptor, we have reported a relationship between the dual stimulator/inhibitor effect of EGF and the activity of the serine/threonine p42 mitogen-activated protein (MAP) kinase. Indeed, a growth stimulatory concentration of EGF is shown to lead to a moderate but persistent activation of p42 MAP kinase. Conversely, an early peak of MAP kinase activation, that rapidly falls below the basal level, is observed in the presence of a growth-inhibitory concentration of EGF. To assess the mechanism of the p42 MAP kinase inactivation under circumstances of negative growth regulation by EGF, we have investigated the role of the serine/threonine phosphatase 2A in this process. A constitutive phosphatase 2A activity was observed in untreated cells, that decreases rapidly in response to both high and low EGF concentrations. However, after this early inactivation, the phosphatase 2A activity was completely reversed concurrently with MAP kinase inactivation, after 40 min of treatment with 10 nM EGF. Conversely, in cells treated with 1 pM EGF, phosphatase 2A activity remained below the control level during all the time of the treatment, in association with a sustained MAP kinase activation. These results suggest that MAP kinase inactivation is closely related to phosphatase 2A activation. We then investigated the effect of the serine/threonine phosphatase inhibitor okadaic acid on the MAP kinase inactivation and observed that okadaic acid, at a concentration reported to specifically inhibit phosphatase 2A activity, totally reverses the MAP kinase inactivation induced by long-term treatment with 10 nM EGF. Additionally, we have shown that the protein synthesis inhibitor cycloheximide fails to affect the EGF-induced MAP kinase regulation, indicating that mitogen-induced protein phosphatases are not, or are only slightly, required in this regulation. In conclusion, our data demonstrate that the ambivalent action of EGF on the proliferation of A431 cells is associated with differential mechanisms of p42 MAP kinase regulation catalysed by the serine/threonine phosphatase 2A.

Testosterone metabolism in primary cultures of human prostate epithelial cells and fibroblasts

We compare testosterone (T) metabolism in primary cultures of epithelial cells and fibroblasts separated from benign prostate hypertrophy (BPH) and prostate cancer tissues. In all cultures, androstenedione (delta 4) formed by oxidation of T by 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) represented 80% of the metabolites recovered. The amounts of 5 alpha-dihydrotestosterone (DHT), formed by reduction of T by 5 alpha-reductase (5 alpha-R), were small: 5 and 2% (BPH) and 8 and 15% (adenocarcinoma) for epithelial cells and fibroblasts, respectively. Northern blot analysis of total RNA from epithelial cells (BPH or adenocarcinoma) attributed the reductive activity to the 5 alpha-reductase type 1 isozyme and oxidative activity to the 17 beta-HSD type 2. In cancer fibroblasts, only little 17 beta-HSD type 2 mRNA was detected. The 5 alpha-reductase inhibitors, 4-MA (17 beta-(N,N-diethyl)carbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one) and finasteride, inhibited DHT formation with a preferential action of 4-MA on epithelial cells (BPH or adenocarcinoma) and of finasteride on fibroblasts from adenocarcinoma. Neither inhibitor acted on delta 4 formation. On the other hand, the lipido-sterol extract of Serenoa repens (LSESr, Permixon) inhibited the formation of all the T metabolites studied [IC50 S = 40 and 200 micrograms/ml (BPH) and 90 and 70 micrograms/ml (adenocarcinoma) in epithelial cells and fibroblasts, respectively]. These results have important therapeutic implications when selecting appropriate treatment options for BPH.

Alpha-thalassaemia and globin gene rearrangements in French Polynesia

The prevalence of alpha-thalassaemia and various globin gene rearrangements was determined in 1992 individuals living on 11 islands in French Polynesia. The gene frequencies for alpha(+)-thalassaemia (almost exclusively the -alpha 3.7III deletion form) range from 5.3% to 19.2%. Haematological indices on 177 heterozygotes and 27 homozygotes for the -alpha 3.7III variant showed considerable overlap with indices of normal individuals; although there was a broad correlation of average indices with alpha-globin genotype, individual values were a poor indication of genotype. A non-deletion form of alpha(+)-thalassaemia (alpha alpha Th), triplicated alpha genes (alpha alpha alpha) and single zeta gene (-zeta) chromosomes were present at low frequencies (< 1%), whereas triplicated gamma gene (gamma gamma gamma) and triplicated zeta (zeta zeta zeta) arrangements were more common (1.1-16.3%). alpha 0-thalassaemia, probably introduced from Southeast Asia in the early part of this century, was observed in a number of individuals of Chinese and Chinese/Polynesian ancestry. Because of the high frequency of alpha(+)-Thalassaemia on some islands, it therefore seems likely that haemoglobin H disease (resulting from the interaction between alpha 0 and alpha(+)-thalassaemia) must occur in parts of French Polynesia.

Human prostatic steroid 5 alpha-reductase isoforms--a comparative study of selective inhibitors

The present study describes the independent expression of the type 1 and 2 isoforms of human 5 alpha-reductase in the baculovirus-directed insect cell expression system and the selectivity of their inhibition. The catalytic properties and kinetic parameters of the recombinant isozymes were consistent with published data. The type 1 isoform displayed a neutral (range 6-8) pH optimum and the type 2 isoform an acidic (5-6) pH optimum. The type 2 isoform had higher affinity for testosterone than did the type 1 isoform (Km = 0.5 and 2.9 microM, respectively). Finasteride and turosteride were selective inhibitors of the type 2 isoform (Ki (type 2) = 7.3 and 21.7 nM compared to Ki (type 1) = 108 and 330 nM, respectively). 4-MA and the lipido-sterol extract of Serenoa repens (LSESr) markedly inhibited both isozymes (Ki (type 1) = 8.4 nM and 7.2 micrograms/ml, respectively; Ki (type 2) = 7.4 nM and 4.9 micrograms/ml, respectively). The three azasteroids were competitive inhibitors vs substrate, whereas LSESr displayed non-competitive inhibition of the type 1 isozyme and uncompetitive inhibition of the type 2 isozyme. These observations suggest that the lipid component of LSESr might be responsible for its inhibitory effect by modulating the membrane environment of 5 alpha-reductase. Partially purified recombinant 5 alpha-reductase type 1 activity was preserved by the presence of lipids indicating that lipids can exert either stimulatory or inhibitory effects on human 5 alpha-reductase.

Comparative study of four extraction procedures for urokinase type plasminogen activator and plasminogen activator inhibitor-1 in breast cancer tissues

The urokinase type plasminogen activator (u-PA) and the plasminogen activator inhibitor-1 (PAI-1) are among the best second-generation prognostic tissue factors in breast cancer. However, different extraction procedures and assay kits are used in different laboratories. A total of 79 breast tumour tissues stored in liquid nitrogen were analysed in this study. We compared u-PA and PAI-1 levels determined with the American Diagnostics (AD) kit after various extraction procedures. The median cytosolic extraction yield in the presence of 0.4 mol/l KCl, calculated relative to extraction in the presence of 10 ml/l Triton X100 when adapted to standard laboratory working hours (incubation for 2 h instead of 12 h) was 74.4% for u-PA and 85.8% for PAI-1. In addition, the correlations were acceptable. Cytosolic extracts prepared with KCl could permit optimal u-PA and PAI-1 assays while also enabling hormone receptors to be determined with the same specimens. Further studies with clinical data are now necessary to determine the prognostic relevance of this extraction procedure.

Inflammatory carcinomas of the breast: a clinical, pathological, or a clinical and pathological definition?

Some controversy remains about the clinical or pathological definition of the different types of inflammatory breast cancer (IBC) and especially the diagnostic and prognostic value of dermal lymphatic involvement. Our purpose was to classify the different types of IBC for which diagnosis was confirmed intraoperatively and ascertain features allowing reliable diagnosis. We studied clinical findings, biological data, and treatment outcome in a series of 144 successive patients. Our results suggest that there are 2 biologically different entities i.e., true IBC and pseudo-IBC. True IBC, whose course is currently fatal in all cases, can be divided into 2 sub-categories i.e., common true IBC (75.7% of cases), in which inflammatory signs occur primarily or secondarily, and occult true IBC (13.2% of cases). Dermal emboli have been observed in 61% of common true IBC, but their absence did not alter the rapidly unfavourable outcome. Extensive lymph-node involvement, other biological features and survival were the same in the 2 sub-categories. Pseudo-IBC (11.1% of cases) can easily be confused with common true IBC. The biological characteristics of pseudo-IBC differ from those of true IBC: no dermal lymphatic involvement and little or no lymph-node involvement. Despite large tumour size, outcome was particularly favourable. It is of great importance to differentiate true and pseudo-IBC, for which the treatments are different. Confirmation of true IBC requires pathological demonstration of dermal lymphatic emboli or extensive lymph-node involvement. Occult IBC must be identified for patients presenting rapidly growing tumours.

Age as a prognostic factor in breast cancer: relationship to pathologic and biologic features

The relationship of age with prognostic factors and outcome of breast cancer has long been controversial due to numerous confounding factors. In order to clarify the prognostic value of age, we analyzed a homogeneous population of 1,266 patients treated for breast cancer at the same institution (mean follow-up: 62 months). Three groups were compared: patients under 35 years of age, non-menopausal patients over 35 years of age, and post-menopausal patients under the age of 70 years. A higher frequency of undifferentiated tumors, histoprognostic grade-3 cancer, microscopic lymph-node involvement and negative hormonal receptor status was observed in patients under 35 years. In addition, clinical but not anatomical tumor size was greater in young patients, suggesting higher stromal activity. Metastasis-free survival and overall survival were significantly poorer before 35 years. Differences were observed when patients were matched with regard to stage, anatomic size, histoprognostic grade, microscopic lymph-node involvement and receptor status. Multivariate analysis of both overall and metastasis-free survival demonstrated that age younger than 35 years was an independent risk factor. Younger women had a higher risk of local recurrence but, unlike older women, they did not experience any worsening of the already unfavorable outcome due to recurrence.

Variation in the vector competence of Aedes polynesiensis for Wuchereria bancrofti

The vector competences of 6 geographic strains of Aedes polynesiensis for Wuchereria bancrofti were studied using two types of experimental infections. Experimental infection of laboratory-bred mosquitoes fed on the carriers' forearms with different levels of microfilaraemia showed that microfilariae (mf) uptake was directly proportional to the carrier's mf density and, as mf densities decreased, concentration capacity of Ae. polynesiensis increased. It was also shown that infection has an important effect on mosquito mortality, and that the mortality rate differed among mosquito strains. In infections using artificial feeders, the mf uptake was closely regulated, thus showing differences in the vectorial efficiency of Ae. polynesiensis related to the geographic origin of the mosquito strain. The mosquitoes from the Society archipelago were more efficient intermediate hosts than geographically distant strains when infected with W. bancrofti from an island within the archipelago (Tahiti). Mosquito strains from the Society archipelago developed the highest proportion of infective-stage larvae and exhibited the lowest mortality rate when infected with sympatric Tahitian W. bancrofti.

A direct comparison of GFAP immunocytochemistry and GFAP concentration in various regions of ethanol-fixed rat and mouse brain

Glial fibrillary acidic protein (GFAP) immunostaining is the most commonly used method to examine the distribution of astrocytes and the hypertrophy of astrocytes in response to neural degeneration or injury. More recently, a variety of biochemical assays for GFAP have been developed. Both qualitative immunocytochemical evaluations of GFAP and quantitative biochemical measurements of GFAP have been used to examine the regional distribution of GFAP within the central nervous system (CNS). The former method has largely been based on aldehyde-fixed tissue, while the latter approach has been based on the use of fresh tissue extracts or homogenates. In the present study, we used ethanol as a fixative to permit both immunocytochemical and biochemical procedure to be carried out on brain tissue from a single animal. Normal adult rats and mice were perfused with a 70% ethanol/saline solution, and each brain was hemisectioned. The concentration of GFAP was measured in regions of 1 hemisection, using an enzyme-linked immunosorbent assay (ELISA), while the other hemisection was used for GFAP immunostaining. Regional differences occurred in the brains of both species, with the highest concentration of GFAP found in the brainstem, and the lowest concentrations found in the striatum and cortex. The specific patterns of GFAP immunoreactivity corresponded to regional concentrations in most brain area of both species. These data show that it is possible to assay GFAP concentrations in tissue prepared for immunocytochemical analysis, providing both qualitative and quantitative information from one set of tissue.

Prognostic value of cytosolic thymidine kinase activity as a marker of proliferation in breast cancer

Thymidine kinase (TK) is involved in DNA synthesis by the salvage pathway. In this study, thymidine kinase (TK) was determined in routinely prepared cytosols of primary tumors from 290 breast-cancer patients. Enzyme activity was measured using a radioenzymatic method optimized for detection of the fetal isoenzyme. High levels of TK (> or = 126 mU/mg protein) were positively associated with histological grade in both pre/peri-and post-menopausal patients. In pre/peri-menopausal patients, high concentrations of TK were also found more frequently in progesterone receptor (PgR)-negative tumors than in PgR-positive samples. In post-menopausal patients, high levels of TK were associated with large tumor size, estrogen receptor (ER) negativity and PgR negativity. In univariate analysis, high levels of TK were strongly associated with shorter overall survival in both pre/peri- (p = 0.001) and post-menopausal patients (p = 0.02). Pre/peri-menopausal patients whose tumors had high levels of TK also had an increased risk of relapse (p = 0.001). In multivariate analysis (including treatment protocol, patient age, lymph-node involvement, tumor size, histological grade, ER and PgR status), TK status was found to be an independent prognostic factor for recurrence-free survival in pre/peri-menopausal patients with a weight similar to that of PgR status. In post-menopausal patients, TK was the only factor selected for overall survival.

Clinical and biologic prognostic factors in breast cancer diagnosed during postmenopausal hormone replacement therapy

OBJECTIVE

To ascertain the influence of hormone replacement therapy on clinical and biologic prognostic factors of breast cancer.

METHODS

Between 1976-1992, we treated 1081 postmenopausal women for breast cancer at our institution. Of these, 68 were undergoing postmenopausal hormone replacement therapy at the time of diagnosis. These patients were compared with a matched control group of 272 breast cancer patients who had not undergone prior hormone replacement therapy.

RESULTS

Patients who developed breast cancer during hormone replacement therapy had fewer locally advanced cancers (large tumors and extensive lymph node involvement) and more well-differentiated cancers (infiltrating lobular cancers and grade 1 cancer). The number of patients with estradiol or progesterone receptors was lower in the hormone-treated group. Metastasis-free survival curves showed a tendency (P = .05) for better prognosis in hormone-treated patients both overall and in stage T2.

CONCLUSIONS

Hormone replacement therapy per se does not affect the prognosis of breast cancer. Regular surveillance during hormone replacement therapy reduces the number of locally advanced cancers and thus improves the survival rate. The higher number of well-differentiated cancers and the distribution of hormone receptivity may reflect interaction between neoplastic tissue and exogenous hormones.

Steroid receptor distribution in 47,892 breast cancers. A collaborative study of 7 European laboratories. The EORTC Receptor Study Group

Seven laboratories of the EORTC Receptor Study Group reported the distribution of oestrogen (ER) and progesterone receptors (PR) routinely assayed in breast cancer cytosols. A low interlaboratory variability was demonstrated for the median values, and for the frequency of positive tumours as measured by enzyme immunoassay (EIA). Larger variations were found for the frequency of positive tumours, as measured by radioligand binding assay (RLA). They are probably due to differences in the cut-off levels and in the sensitivity of the assay. Analysis of the variability over time clearly demonstrated that the ER-EIA values initially increased compared with RLA. A possible source of variations could be the calibration drift in the ER-EIA kit. In conclusion, quality assessment of steroid receptors should be monitored by comparison of both common standards and distributions routinely obtained in each laboratory. In-house analysis over time is also essential for reagent survey.

Double-blind controlled trial of a single dose of the combination ivermectin 400 micrograms/kg plus diethylcarbamazine 6 mg/kg for the treatment of bancroftian filariasis: results at six months

In 1993, a three-arm double-blind controlled trial was implemented in French Polynesia to compare the tolerance and efficacy of a single dose of the combination ivermectin (IVR) 400 micrograms/kg plus diethylcarbamazine (DEC) 6 mg/kg vs. IVR 400 micrograms/kg alone vs. DEC 6 mg/kg alone, for treatment of Wuchereria bancrofti carriers. Of the 57 treated male patients in whom microfilaria (mf) densities ranged from 22 to 4709 mg/mL, 3 groups of 19 were randomly selected and allocated to one of the 3 treatments. Side effects were experienced by 34 patients (60%), but none suffered a severe reaction. Grade of reaction did not differ between treatment group, but was significantly correlated with the pretreatment mf density. Six months after treatment, 26%, 32% and 53% of patients were amicrofilaraemic in the DEC, IVR and IVR+DEC groups, respectively. Mf levels were 6.3%, and 3.1% and 1.0% of the pretreatment level, respectively, significantly lower in the IVR+DEC group than in both the IVR and DEC comparison groups. The combination IVR+DEC showed promise in term of sustained mf decrease, and could be an effective alternative for lymphatic filariasis control programmes.

Biological heterogeneity of ER-positive breast cancers in the post-menopausal population

In the natural history of post-menopausal patients with primary breast cancer, high estrogen receptor levels (ER) have been associated with a poor recurrence-free survival. The purpose of this study was to investigate whether there are any biological intratumoral characteristics to support this puzzling clinical observation. In a population of 542 post-menopausal, primary-breast-cancer patients, 3 normal distributions fitted into the frequency distribution curve of the logarithmically transformed ER-EIA values. The biological profiles of the low ER group, and of the intermediate and high ER groups identified in the ER-positive population were compared. Parameters correlated with ER functional aspect (progesterone receptors and PS2), receptors of epidermal growth factor (EGFR), protease cathepsin D and tumor proliferation (deduced from thymidine kinase activity) were analyzed. As previously reported, the levels of progesterone receptors and PS2 increased significantly from the low to the high ER groups. The highest levels of cathepsin D and thymidine kinase which have been previously related to a poor prognosis in breast cancer were found in the low ER group, but high levels were, surprisingly, also found in the high ER group. This study indicates that the ER-positive post-menopausal population is biologically heterogeneous. The high levels of thymidine kinase found in the high ER group suggest that overexpression of ER may be associated with proliferation enhancement, partly explaining the poor spontaneous prognosis related to this subset.

Characterization of 17 beta-hydroxysteroid dehydrogenase activity and mRNA abundance in human meningioma tumors

Meningioma benign tumors possess significant levels of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity. Two different 17 beta-HSDs have been cloned and characterized. The cytosolic 17 beta-HSD I which exclusively catalyzes the interconversion of 17 beta-estradiol (E2) and estrone (E1) preferentially uses NADP+ and NADPH as cofactors. In contrast, the mitochondrial-microsomal 17 beta-HSD II catalyzes both the estrogenic as well as the androgenic substrates of the 17 beta-HSD and uses NAD+ and NADH as cofactors. We demonstrated here that the 17 beta-HSD activity in meningioma tissue homogenate is both estrogenic and androgenic with Km values of 2.4, 0.4, 14.7, and 2.0 microM for E2, E1, testosterone (T), and delta 4-androstenedione (delta 4), respectively. NAD(+)-NADH is almost exclusively used as cofactor in this tissue. Moreover, fractionation of meningioma tissue revealed that most of the 17 beta-HSD activity is present in the mitochondrial-microsomal fraction. Although Northern blot analysis on meningiomas with a specific probe for human 17 beta-HSD I showed no band, the specific cDNA probe of human 17 beta-HSD II hybridized at the expected size of 1.5 kb, which was also present in placenta. On four different meningioma tumors, we were able to correlate 17 beta-HSD II mRNA expression to high levels of 17 beta-HSD activity. Taken together, the present data suggest that the meningioma 17 beta-HSD could be the 17 beta-HSD II.

Relationship between the MAP kinase activity and the dual effect of EGF on A431 cell proliferation

EGF is involved in the regulation of cell proliferation in normal as well as in neoplastic tissues. The A431 cells that over-express EGFR, display in vitro ambivalent growth properties in response to EGF, since stimulation induced by low concentrations (10(-12) M-10(-10) M) is reversed with increasing concentrations (10(-9) M-10(-8) M). To assess differential mechanisms of signal transduction that determine growth stimulatory and inhibitory activity, we have studied the MAP kinase activation induced by mitotic and antimitotic concentrations of EGF. We demonstrate that the presence of a growth stimulatory concentration of EGF (10(-12) M) leads to a moderate but persistent activation of p42 MAP kinase during all the time of the EGF treatment. Conversely, an early peak of kinase activation that rapidly falls down below the basal level, is observed when a growth inhibitory concentration of EGF (10(-8) M) is used. Moreover, the addition of Na-orthovanadate in 10(-8) M EGF-treated cells leads to the rescue of the MAP kinase activity, suggesting that the loss of kinase activity induced by growth inhibitory EGF concentrations involves the dephosphorylation of the MAP kinase. In conclusion, our data demonstrate that the dual effect (stimulator/inhibitor) of EGF on the proliferation of A431 cells is associated to differential mechanisms of p42 MAP kinase regulation.

[Prognostic value of urokinase-type plasminogen activator and 2 inhibitors PAI-1 and PAI-2 in breast cancer]

It is now clearly established that proteolytic enzymes, and in particular plasminogen activator (uPA), play an important role in breaking down the extracellular matrix, which is considered to be a step in metastasis formation. Plasminogen activators are controlled at various levels. Two inhibitors, PAI-1 and PAI-2, have been identified, the latter being more specific for uPA. In attempts to determine their prognostic value, it is essential to investigate the relative importance of these parameters and their interactions. We used an immunoenzymatic method to assay uPA, PAI-1 and PAI-2 antigens in cytosols prepared from 314 primary breast tumors. The patients were followed up for a minimum of six years and all relevant clinical and laboratory findings had been recorded. Univariate analysis confirmed the poor outcome of patients whose tumors contained large amounts of uPA and PAI-1. In addition, low levels of PAI-2 correlated with shorter disease-free survival in the overall population (P = 0.02), post-menopausal women (P = 0.02) and women without lymph node involvement (P = 0.02). Multivariate analysis using the "Main Effects" Cox model identified node involvement, macroscopic tumor size and PAI-2 as significant variables. The "interactive" Cox model, taking into account interactions between uPA and its two inhibitors, identified a first subgroup with a very poor prognosis associating either high levels of PAI-1 with low levels of PAI-2 in the overall population as well as following stratification for axillary node negative disease, or high levels of uPA with low levels of PAI-2 in the group of menopausal women. We conclude that PAI-1 provides the same prognostic informations as uPA, and does not appear to play its role as an inhibitor. In contrast, PAI-2 increased the prognostic value of both uPA, particularly in post-menopausal women, as well as PAI-1 in a subgroup of axillary node negative patients.

Efficacy of ivermectin for the treatment of head lice (Pediculosis capitis)

Twenty six male and female patients aged 5 to 17 years who had head lice infestation confirmed by eggs presence and received treatments with a single 200 mu/kg oral dose of ivermectin in open fashion. At day 14 after treatment, 20 responded to the treatment (77%), and 6 patients (23%) presented with a complete disappearance of eggs and all clinical symptoms. At day 28, 7 patients were healed (27%), but 4 patients of the 6 healed at day 14 presented with signs of reinfestation. This study suggests that ivermectin is a promising treatment of head lice, and a second dose at day 10 should be appropriate for a further comparative trial.