Natural attenuation of zinc pollution in smelter-affected soil.

Previous synchrotron X-ray microprobe measurements of Zn speciation in contaminated and uncontaminated soils have identified phyllosilicate as the main sequestration phase. The emphasis now is focused on comparing the nature and properties of neoformed and geogenic phyllosilicate species to understand natural attenuation processes. Refined structural characterization of the two types of Zn-containing phyllosilicate in slightly basic smelter-affected agricultural soils were obtained using a so far unprecedented combination of X-ray microscopic techniques, including fluorescence (µ-XRF), absorption (µ-EXAFS), and diffraction (µ-XRD), and X-ray bulk-sensitive techniques, including powder and polarized EXAFS spectroscopy. The unpolluted and polluted species are both dioctahedral smectites, but the first which contains minor Zn (ca. 150 mg/kg) is aluminous and Fe-free, and the second, which contains several hundreds to a few thousands mg/kg Zn depending on the distance to the smelter and wind direction, is ferruginous with an average Fe/Al atomic ratio of 1.1 ± 0.5. The Zn(2+) and Fe(3+) in the neoformed smectite are derived from the weathering of ZnS, ZnO, FeS(2), and ZnFe(2)O(4) particles from the smelter. These cations diffuse away from their particulate mineral sources and coprecipitate with Al and Si in the soil clay matrix. Zinc sequestration in the octahedral sheet of dioctahedral smectite is potentially irreversible, because this type of phyllosilicate is stable over a large pH range, and the neoformed species is analogous to the native species which formed over time during pedogenesis.

Supplementation of MCF-7 cells with essential fatty acids induces the activation of protein kinase C in response to IGF-1.

The effects of changing the composition of membrane lipids on protein kinase C (PKC) activation were studied in MCF-7 human breast cancer cells. The supply of linoleate or alpha-linolenate to MCF-7 cells altered cell membranes fatty acid composition but did not affect PKC activity. When the cells were additionally exposed to IGF-1, the same fatty acids caused a dramatic increase in membrane-bound PKC activity. We also found that the mitogenic response induced by IGF-1 was not enhanced in those conditions when PKC becomes activated by linoleate and alpha-linolenate. These data show that these fatty acids elicit a distinct route for the transmission of IGF-1 signal by inducing the PKC pathway. They suggest that linoleate and alpha-linolenate could control the biological response of MCF-7 cells to IGF-1.

Membrane fatty acids of breast carcinoma: contribution of host fatty acids and tumor properties.

To assess the part that host fatty-acid supply and tumor-specific fatty-acid utilization contribute to the membrane lipid composition of tumor tissue, intra-individual comparisons of membrane fatty acids were carried out between breast-carcinoma tissue and non-tumorous breast tissue adjacent to the tumor and taken as reference. Phospholipids were purified by thin-layer chromatography from tumor biopsies obtained from 59 patients with a localized presentation of breast cancer, and fatty acids analyzed by capillary gas chromatography. Elevated levels of palmitic, palmitoleic and arachidonic acids, along with a low level of linoleic acid, were observed in membrane phospholipids of tumors with poor histoprognostic grade. The level of mono-unsaturated fatty acids was higher, and the level of essential fatty acids was lower in the tumor than in the reference breast tissue. Fatty-acid-desaturating activity was not detectable in tumors. A positive relationship was observed among patients for most of the fatty acids between carcinoma and non-tumorous breast tissue, except for mono-unsaturated and essential fatty-acid levels, which were not correlated between both tissues. These data suggest that mechanisms specifically related to malignant transformation and tumor progression influence the membrane fatty-acid profile of breast carcinoma. Fatty acid supply to the tumor, possibly modified by metabolic conditions related to the host, also seems to play a decisive role in this composition.

Analysis of the lipid content and the motility of human sperm after follicular fluid treatment.

The effect of human follicular fluid (hFF) on the cholesterol and phospholipid content and the movement characteristics of human spermatozoa were studied. Semen was selected by a discontinuous Percoll gradient and incubated during in vitro capacitating conditions with B2 medium supplemented with hFF 20%. Percoll pelleted spermatozoa were incubated in either B2 (B2-Percoll) or B2 supplemented with hFF (hFF-Percoll). In hFF-Percoll, we observed a time-dependent (24 h) decrease in both the cholesterol and phospholipid contents (cholesterol: 10.1 vs. 8.7 nmol 10(-7) spermatozoa; phospholipids: 17.5 vs. 15.7 nmol 10(-7) spermatozoa, P < 0.05). This decrease in cholesterol and phospholipids in human spermatozoa was concomitant with a high straight line velocity, a high progressive motility percentage and an increased value of lateral head displacement without any significant alteration of the spermatozoal membrane. No modification of the cholesterol: phospholipid ratio after 2 and 24 h of incubation in either B2-Percoll (0.61, 0.54) in hFF-Percoll (0.59, 0.63) was observed when compared with original control semen. It is suggested that the decrease in cholesterol and phospholipids in hFF-Percoll may be taken into account for the changes of membrane modification as part of the capacitation process.

[Follicular fluid: role and importance in the preparation of spermatozoa for fertilization]. / Fluide folliculaire: rôle et importance dans la préparation des spermatozoïdes à la fécondation.

It has been demonstrated that the preovulatory follicular fluid creates a micro-environment which is of importance for normal sperm function. In this paper, we attempt to evaluate the role of human follicular fluid (HFF) on the fertilizing capacity of spermatozoa.

Triacylglycerol structure of human colostrum and mature milk.

Because triacylglycerol (TAG) structure influences the metabolic fate of its component fatty acids, we have examined human colostrum and mature milk TAG with particular attention to the location of the very long chain polyunsaturated fatty acid on the glycerol backbone. The analysis was based on the formation of various diacylglycerol species from human milk TAG upon chemical (Grignard degradation) or enzymatic degradation. The structure of the TAG was subsequently deduced from data obtained by gas chromatographic analysis of the fatty acid methyl esters in the diacylglycerol subfractions. The highly specific TAG structure observed was identical in mature milk and colostrum. The three major fatty acids (oleic, palmitic and linoleic acids) each showed a specific preference for a particular position within milk TAG: oleic acid for the sn-1 position, palmitic acid for the sn-2 position and linoleic acid for the sn-3 position. Linoleic and alpha-linolenic acids exhibited the same pattern of distribution and they were both found primarily in the sn-3 (50%) and sn-1 (30%) positions. Their longer chain analogs, arachidonic and docosahexaenoic acids, were located in the sn-2 and sn-3 positions. These results show that polyunsaturated fatty acids are distributed within the TAG molecule of human milk in a highly specific fashion, and that in the first month of lactation the maturation of the mammary gland does not affect the milk TAG structure.

A cross-linking assay allows the detection of receptors for the somatostatin analogue, lanreotide in human breast tumours.

Hypothalamic somatostatin and its synthetic analogues inhibit the cell growth of several tumour models. The somatostatin analogue lanreotide (somatuline or BIM23014C) inhibits both the in vivo and in vitro cell growth of various mammary tumours. In order to evaluate the presence of receptors for lanreotide in breast tissue, samples from 41 female and 2 male patients were analysed by a cross-linking assay. All the samples examined possessed at least one subtype of lanreotide binding polypeptide, however, different polypeptide patterns were observed. The two major complexes had molecular weights of 57 kD and 42 kD. The previously demonstrated antiproliferative activity of lanreotide and the high percentage of positive tumours supports the use of lanreotide in clinical trials. However, the role of each receptor subtype in the control of breast cell proliferation requires further characterisation.

Treatment of human spermatozoa with follicular fluid can influence lipid content and motility during in vitro capacitation.

In order to evaluate the role of human follicular fluid (HFF) on the fertilizing capacity of spermatozoa, we studied the effect of HFF on the lipid composition and on the movement characteristics of human spermatozoa. Spermatozoa (spz) from normospermic patients were prepared with a discontinuous Percoll gradient and incubated in Ménézo B2 medium with or without a supplement of 20% HFF (HFF-Percoll spz and B2-Percoll spz respectively) for 2 and 24 h. After 2 h HFF incubation, percentage progressive motility, straight line velocity (VSL), and amplitude of lateral head displacement (ALH) were improved in HFF-Percoll spz as compared to B2-Percoll spz (P < or = 0.05). After a longer incubation period (24 h), lipid changes appeared in HFF-Percoll spz with lower levels of cholesterol (P = 0.02) and phospholipids (P = 0.05). No modification of the cholesterol/phospholipid ratio after 2 and 24 h of incubation in either B2-Percoll spz or HFF-Percoll spz was observed. Such decreases in lipid content of HFF-Percoll spz may be factors which could be taken into account as constituting part of membrane modifications during the capacitation process.

Prognostic significance of tumor phosphatidylcholine stearic acid level in breast carcinoma.

The involvement of lipid enzymes in the action of oncogenes at the cell membrane level has suggested that membrane lipids could play a role in modulating the growth of tumors. We previously found that breast cancer patients with a low level of polyunsaturated fatty acids in their primary tumor's phosphatidylethanolamine had a high risk of early occurrence of visceral metastasis. In the present study, we prospectively examined whether fatty acid composition of tumor membrane phosphatidylcholine had a prognostic significance in a series of 63 patients with a localized presentation of breast cancer. Membrane phospholipids were extracted from the carcinoma tissue obtained at the time of surgery, phosphatidylcholine was purified, and its fatty acids were analyzed by capillary gas chromatography. During the follow-up period, 20 patients developed metastasis. In these patients, the proportion of stearic acid containing phosphatidylcholine was significantly lower than it was in the tumors of the 43 patients who remained metastasis-free. Multivariate analysis according to Cox showed that low stearic acid level in tumor phosphatidylcholine and high mitotic index were independently predictive of subsequent metastasis. The predictive value of stearic acid level on metastasis risk was higher in node-positive patients than in node-negative patients, allowing individualization of a subgroup of low stearic acid level, node-positive patients with very poor prognosis. We concluded that stearic acid level in tumor membrane phosphatidylcholine is an independent intra-tumor marker of breast cancer prognosis. This finding is new evidence that tumor's structural lipids are linked to the growth of breast cancer.

Fatty-acid composition of breast and iliac adipose tissue in breast-cancer patients.

In order to determine to what extent the fatty-acid composition of breast adipose tissue is representative of the body-fat composition in breast carcinoma, we compared the fatty-acid composition of breast adipose tissue to that of iliac fat in breast-cancer patients. Triglycerides from the 2 sites were purified by thin-layer chromatography and fatty-acid composition was determined by capillary gas chromatography. Compared with iliac fat, mammary fat was higher in saturated (33.2 +/- 3.9 vs. 24.4 +/- 1.6%; p = 0.0001) and lower in mono-unsaturated (48.0 +/- 2.2 vs. 54.8 +/- 2.7%; p = 0.0001) and poly-unsaturated fatty acids (16.6 +/- 3.7 vs. 18.0 +/- 3.1%; p = 0.0001). A positive correlation was found between the 2 sites for linoleate (r = 0.95; p = 0.0003), alpha-linolenate (r = 0.83; p = 0.01), palmitate (r = 0.78; p = 0.02) and palmitoleate (r = 0.76; p = 0.02). No relationship was observed for stearic and oleic acids. We conclude that breast and iliac fat differ with regard to fatty-acid composition. The interpretation of fatty-acid composition of the body stores in breast-cancer patients, as an indicator of long-term intake of dietary fat, should take into account the sampling site of stored lipids.

Molecular heterogeneity of somatostatin analogue BIM-23014C receptors in human breast carcinoma cells using the chemical cross-linking assay.

Distinct proteins complexed with somatostatin and the somatostatin analogue BIM-23014C were revealed in human breast cancer cells using the cross-linking assay. One BIM-23014C-specific complex (Mr 57,000) was observed in MCF-7 (monolayer, nodule, and tumor) and T47D. Growth inhibition of MCF-7 tumor xenografts by BIM-23014C was dose related in the 6-day subrenal capsule assay. Three complexes (Mr 27,000, 42,000, and 57,000) were detected in MDA-MB-231, and no complex was visible in HBL-100. No correlation was found between receptors for BIM-23014C and epidermal growth factor in these lines. Twenty-seven of 30 human breast tumors (90%) had at least one BIM-23014C receptor. Sixteen had three complexes (Mr 27,000, 42,000, and 57,000). Six had the two complexes (Mr 27,000 and 57,000), two had Mr 42,000 and 57,000 complexes, two had just the Mr 27,000 complex, and one had just the Mr 42,000 complex. The presence of the three BIM-23014C receptors was positively correlated (P less than 0.05) to the low amount of sex steroid receptors (less than 20 fmol/mg) [seven of eight (estrogen receptor negative, progesterone receptor negative) versus four of 14 (estrogen receptor positive, progesterone receptor positive)]. Another positive correlation was established between the absence of progesterone receptors and the presence of these three complexes [12 of 16 (progesterone receptor negative) versus four of 14 (progesterone receptor positive)]. This high percentage of BIM-23014C receptor-positive biopsies and its inhibitory activity would support its clinical potential for the treatment of breast cancer.

Essential fatty acid composition of human colostrum triglycerides: its relationship with adipose tissue composition.

The relationships between essential fatty acid (EFA) composition of colostrum and white adipose tissue (WAT) were examined on day 5 after delivery in 69 healthy women. Fatty acid composition was assessed by capillary gas chromatography, and 33 fatty acids were detected in colostrum and in WAT. Total polyunsaturated fatty acid (PUFA) content was similar in colostrum and in WAT (15.7 +/- 3.1% and 16.1 +/- 3.8%, respectively), but long-chain PUFA content was higher in colostrum than in WAT (2.9 +/- 0.6% and 1 +/- 0.2%, respectively; P less than 0.001). The concentrations of linoleic acid were significantly correlated between colostrum and WAT (r = 0.77, P less than 0.0001). No correlation was found for alpha-linolenic acid. The relationships between long-chain PUFA composition of colostrum and WAT suggested that individual factors along with tissue specificity of the mammary gland are involved in either the capacity of desaturating and chain-elongating pathways and/or incorporation of long-chain PUFAs into colostrum.

Conformational variations in d(TGACGTCA) and its reverse sequence d(ACTGCAGT): a joint circular dichroism and nuclear magnetic resonance study.

Circular dichroism (CD) and nuclear magnetic resonance (NMR) techniques have been used to characterize the structural properties of the two self-complementary DNA octamers d(TGACGTCA) (I) and d(ACTGCAGT) (II). These display as distinctive features reverse sequences and central steps CpG and GpC, respectively. CD experiments lead to B-form DNA spectra characterized by larger magnitude signals in the case of octamer (I). NMR COSY spectra indicate that in the two octamers all the residues are predominantly south, S, (2'-endo) sugar conformation. NMR NOESY spectra show most of the glycosidic angles confined in the range predicted for B-form DNA although important heterogeneity is noticed along the chains, more pronounced in the case of octamer (I). Both the increase of north, N, (3'-endo) sugar conformation and P (pseudorotation phase angle) deviation from its standard B-form DNA value (162 degrees) express local sequence dependent structure distortions, remarkably visible in CpG step of octamer (I) and agreeing with NOESY cross-peaks intensities. Results interpreted according to Calladine's rules indicate higher cross-chain strains in octamer (I) than in octamer (II). All together, we find evidence to support for octamer (I) in solution local structures with A-DNA properties likely dictated by the central CpG step. Such structures could be involved in the DNA recognition by proteins and anticancerous drugs.

Presence of PAF-acether in human breast carcinoma: relation to axillary lymph node metastasis.

PAF-acether (PAF; formerly platelet-activating factor), a potent lipid mediator of inflammation, is involved in multiple cellular functions. To evaluate the role of PAF in human cancer, we obtained specimens from patients with localized breast carcinoma and assayed them for PAF. PAF was found in almost all carcinoma, although it was not detected in most of the matched, nontumor breast tissue samples. Intratumor PAF level was elevated when axillary lymph node involvement was low. Greater axillary extension (two or more positive lymph nodes) was associated with a decreased intratumor PAF level. These findings, along with the independence of other prognostic factors, indicate that PAF is a tumor marker of axillary lymph node involvement.

Chemical characterization and functional role of human glomerular basement membrane components.

Subfractions of human glomerular basement membrane isolated by enzymatic procedures were analyzed for their chemical structure and biological activity. Pepsin or collagenase digestion of purified basement membranes released three groups of components: collagenous and noncollagenous fractions and also a mixed material consisting of a proteolysis-resistant association between collagen sequences and heteropolysaccharidic glycopeptides. These different fractions were explored in vitro for their ability to interact with cell membranes. In fact, only fractions containing the heterogenous material agglutinated human transformed or embryonic cells within 2 h. The cell agglutination was specifically inhibited by N-acetylosamines and N-acetylneuraminic acid. An additional incubation of 20 h at 37 degrees C of the agglutinated cells, maintained in a minimal medium devoid of serum, led to a morphological change of the transformed cells due to an increased cell adhesion and cell spreading. These experimental data suggest that the basement membrane possesses active sites - consisting of an association between collagen and structural glycoproteins - which could play a primordial role in cell matrix interactions.

[Isolation and composition of plasma membranes of bovine glomerulus]. / Isolement et composition des membranes plasmiques du glomérule de boeuf.

Plasma membranes of Beef kidney glomeruli were prepared by ultracentrifugation on a discontinuous sucrose density gradient. They were characterized by specific marker enzyme activities and electron microscopy morphological studies. Amino acid composition revealed a high amount of hydrophobic residues. Carbohydrate amount was found to be as high as 8.9 p. cent of the dry weight.

[Assay of "pregnancy alpha 2 glycoprotein" in the serum of prostatic cancer patients and changes during estrogen therapy]. / Dosage de la "pregnancy alpha 2 glycoprotein" dans le sérum de cancéreux prostatiques et évolution aut cours du traitement oestrogénique.

Preliminary results are presented after measuring Pregnancy alpha 2 glycoprotein (P.A.G.) in a series of healthy males and those with cancer of the prostate, some of whom were being treated with oestrogens. Serum P.A.G. levels were measured in 21 patients with cancer of the prostate to observe any changes occurring during treatment with oestrogens. There was no significant difference between the P.A.G levels in healthy males and those with untreated prostatic cancer. Treatment however causes increased P.A.G. levels with wide individual variations. There is no apparent relationship between P.A.G. levels and the tumor stage, or efficacy of treatment. A relationship does exist however between the curves of serum P.A.G. levels in pregnant women and patients with prostatic cancer treated with oestrogens. Until proved otherwise, these measurements are of no practical value in patients with prostatic cancer, and future confirmation of these results by the study of a larger number of cases would be of value only in that they avoid other teams from repeating the same investigations.

[Isolation of structural glycoproteins from human placenta]. / Isolement de glycoprotéines de structure du placenta humain.

Microfibrils about 100 A wide are isolated by mechanical procedures (sieving and ultrasonic disintegration from villosities of human placenta. Amino acid and carbohydrate compositions seem to be related to structural glycoproteins described before in connective tissues.