Removal of ciprofloxacin from seawater by reverse osmosis.

Much of the deterioration of water resources is anthropogenically caused as a consequence of the incessant production of chemical compounds to obtain the quality of life that society demands today. This constant presence and harmful accumulation of these pollutants in different ecosystems have seen them emerge as a major concern both for human health and for environmental safety. Scientific advances have succeeded in legislating against, reducing and even eliminating priority pollutants, while new technologies are being constantly developed to identify and treat newly emerging pollutants. The objective of this work is the evaluation of the seawater reverse osmosis membrane as a method for the removal of an antibiotic present in seawater. The novelty of the study is that the tests were undertaken using water of high ionic strength. A critical selection of the antibiotic to be used in the study was carried out. The experiments were performed under constant pressure conditions, employing synthetic seawater in a pilot-scale unit with a commercial spiral-wound reverse osmosis membrane. Results are shown in terms of selectivity of the reverse osmosis process for antibiotic removal. The RO membrane element successfully reject most of the ciprofloxacin (removal rate >90%), with maximum rejection value of 99.96%.

The Ski proto-oncogene regulates body composition and suppresses lipogenesis.

OBJECTIVE: The Ski gene regulates skeletal muscle differentiation in vitro and and in vivo. In the c-Ski overexpression mouse model there occurs marked skeletal muscle hypertrophy with decreased adipose tissue mass. In this study, we have investigated the underlying molecular mechanisms responsible for the increased skeletal muscle and decreased adipose tissue mass in the c-Ski mouse. APPROACH: Growth and body composition analysis (tissue weights and dual energy X-ray absorptiometry) coupled with skeletal muscle and white adipose gene expression and metabolic phenotyping in c-Ski mice and wild-type (WT) littermate controls was performed. RESULTS: The growth and body composition studies confirmed the early onset of accelerated body growth, with increased lean mass and decreased fat mass in the c-Ski mice. Gene expression analysis in skeletal muscle from c-Ski mice compared with WT mice showed significant differences in myogenic and lipogenic gene expressions that are consistent with the body composition phenotype. Skeletal muscle of c-Ski mice had significantly repressed Smad1, 4, 7 and myostatin gene expression and elevated myogenin, myocyte enhancer factor 2, insulin-like growth factor-1 receptor and insulin-like growth factor-2 expression. Strikingly, expression of the mRNAs encoding the master lipogenic regulators, sterol-regulatory enhancer binding protein 1c (SREBP1c), and the nuclear receptor liver X-receptor-alpha, and their downstream target genes, SCD-1 and FAS, were suppressed in skeletal muscle of c-Ski mice, as were the expressions of other nuclear receptors involved in adipogenesis and metabolism, such as peroxisome proliferator-activated receptor-gamma, glucocorticoid receptor and retinoic acid receptor-related orphan receptor-alpha. Transfection analysis demonstrated Ski repressed the SREBP1c promoter. Moreover, palmitate oxidation and oxidative enzyme activity was increased in skeletal muscle of c-Ski mice. These results suggest that the Ski phenotype involves attenuated lipogenesis, decreased myostatin signalling, coupled to increased myogenesis and fatty acid oxidation. CONCLUSION: Ski regulates several genetic programs and signalling pathways that regulate skeletal muscle and adipose mass to influence body composition development, suggesting that Ski may have a role in risk for obesity and metabolic disease.

Tumor-specific antigens on rat liver cells transformed in vitro by chemical carcinogens.

With the use of membrane immunofluorescence and xenogeneic antisera, tumor-specific membrane antigens were detected on rat epithelial-like liver cells transformed in vitro by chemical carcinogens. These antigens were not detected in 10-, 15-, and 19-day rat fetuses. Xenogeneic antisera were produced in rabbits by immunization of the rabbits with cultivated BD rat liver cells transformed by dimethylnitrosamine or N-methyl-N'-nitro-N-nitrosoguanidine. The specific antisera against tumor-associated antigen(s) were obtained by in vivo absorption in syngeneic male rats and by in vitro absorption with various cell lines. One tumor-specific individual antigen and two tumor-specific cross-reacting antigens were shown to be present on the surface of chemically and/or spontaneously transformed rat liver cell lines. They were not detected on liver and spleen cells of normal BD adult rats, on fetal liver cells, or on liver and intestinal carcinoma cells of Wistar rats. Sera from multiparous pregnant rats had no antibodies against these tumor antigens (although they reacted with fetal cells).

Selective lack of intercellular communication between transformed and nontransformed cells as a common property of chemical and oncogene transformation of BALB/c 3T3 cells.

BALB/c 3T3 cells can be transformed by transfection of an activated cellular oncogene as well as by chemicals. When the cells were transformed by pEJ-ras transfection, a marked increase in Mr 21,000 protein expression was found by Western blotting and immunohistochemical staining, whereas no such increase was detected in cells transformed by methylcholanthrene, suggesting two different molecular mechanisms. By directly microinjecting a fluorescent dye (Lucifer Yellow CH) into individual cells, we measured junctional intercellular communication among and between transformed and surrounding nontransformed cells. In both chemical and oncogene transformation studies, transformed cells and surrounding normal cells have similar capacities for gap-junctional communication, but there was complete lack of communication between transformed and nontransformed cells. When BALB/c 3T3 cells were transformed by methylcholanthrene initiation followed by phorbol ester promotion, again we saw no intercellular communication between transformed and nontransformed cells, suggesting that the observed selective communication block between transformed and nontransformed cells may be a general phenomenon in BALB/c 3T3 cells. These results indicate that selective lack of intercellular communication between transformed and surrounding normal cells may be an important phenomenon that separates transformed cells and nontransformed cells, permitting transformed cells to maintain autonomous growth.

Inhibitory effect of tumor promoting phorbol esters and mezerein on human mixed lymphocyte reaction.

The effect of phorbol ester-type tumor promoters on the mixed reaction of human lymphocytes was investigated. When a low concentration (10 ng/ml, 1.67 X 10(-8) M) of 12-O-tetradecanoylphorbol-13-acetate (TPA) was added at the beginning of the mixed lymphocyte reaction, this, as measured by [3H]thymidine incorporation, was almost completely inhibited. The inhibitory effect is apparently not related to a toxic effect, since [3H]uridine incorporation was affected to a lesser extent by the addition of TPA. TPA is also inhibitory when added after the reaction has started. The inhibition of the reaction by TPA is very rapid and complete inhibition can be seen within 2 h after TPA addition. Another promoting phorbol ester, phorbol-12,13-didecanoate )PDD), also inhibited the reaction, whereas inactive derivatives, phorbol and 4 alpha-PDD, did not. Mezerein, a weak promoter on mouse skin, was also a potent inhibitor of the human mixed lymphocyte reaction.

Alpha-Fetoprotein levels in normal males from seven ethnic groups with different hepatocellular carcinoma risks.

Alpha-Fetoprotein (AFP) levels of 1,335 males (15 years and older) of seven ethnic groups (Chinese, Indians, and Malays from Singapore, Caucasians from Lyon, and Blacks from Nairobi, forest, and the savanna region of the Ivory Coast) were determined by radioimmunoassay. A few elevated levels (up to 30 nanounits/ml) were detected in some normal individuals, especially in the older age-groups. In addition, there was a systematic age-dependency of AFP levels particularly evident in the groups from Singapore-Lyon, in which there was a 50% AFP increase between the ages of 20 and 40. Comparison between Africans on the one hand and people from Singapore-Lyon on the other hand revealed highly significant differences (p less than 0.001), especially in the younger groups, whereas Chinese, Malays, and Indians from Singapore had very similar AFP pattern; this suggests an important role for environmental factors in the regulation of AFP levels. The age dependency of the presumed effect of environmental factors is in keeping with experimental data showing that young animals respond more vigorously to AFP-stimulating factors. Although the incidence of hepatocellular carcinoma (HCC) differs in the three Singapore groups (the highest in Chinese and the lowest in Indians), no relationship was observed in this study between mean AFP level and HCC incidence in Singapore.

PIP: The levels of alpha fetoproteins (AFP) were quantitated in 7 ethnic groups (Chinese, Indians, and Malays from Singapore, Caucasians from Lyon, and Blacks from the Nairobi, forest, and savanna region of the Ivory Coast) by radioimmunoassay. Sera from 1335 men (aged 15 years or older) were assayed. Mean AFP levels increased with age and varied among populations. A few elevated (30 nU/ml) AFP values were detected in normal individuals, mostly from older age groups. The systematic age-dependency was particularly evident in groups from Singapore-Lyon, in which there was a 50% increase in AFP between age 20 and 40 years. When Africans were compared on the one hand and people from Singapore-Lyon were compared on the other, highly significant differences were revealed in AFP patterns (P .001). This was true especially in the younger groups; whereas Chinese, Malays, and Indians from Singapore had very similar AFP patterns, suggesting an important role for environmental factors in regulation of AFP levels. The age dependency observed paralleled experimental data where laboratory animals responded most vigrously to AFP-stimulating factors the younger they were. Although the hepatocellular carcinoma incidence differs in the 3 Singapore groups (Chinese highest and Indians lowest), no relationship was observed bwtween mean AFP level and hepatocellular carcinoma incidence in Singapore.

Measurement of measles virus-specific neutralizing antibodies: evaluation of the syncytium inhibition assay in comparison with the plaque reduction neutralization test.

Plaque reduction neutralization (PRN) is the "gold-standard" for the measurement of measles-specific neutralizing antibodies. However, it is a complicated assay and tends to be operator-dependent. It has been suggested that the simpler syncytium inhibition assay (SIA) can give results comparable to the PRN test. We compared these two assays using 594 serum or plasma samples obtained from children at various times after natural infection, primary measles immunization, and measles revaccination. The results of the two assays correlated well overall (r = .86; p < 0.0001). The strain of challenge virus (wild-type versus vaccine strain) did not significantly influence SIA titers and the assay performed equally well with serum and plasma. PRN titers > or = 120 and > 800 are thought to indicate protection against clinical illness and infection respectively. The equivalent SIA cut-off values using 125 plaque-forming units as the challenge inoculum were > or = 16 and > 128 respectively. At low PRN titers (< 200), the correlation between PRN and SIA values was reasonable (r = 0.60; p < 0.001) when a challenge inoculum of 12.5 plaque-forming units was used. At the lowest PRN titers (< 100), 15% of the samples gave divergent results. These data confirm the utility of the SIA in the determination of measles-specific neutralizing antibodies when antibody titers are high. However, the PRN assay remains the test of choice when maximum sensitivity at low titers is required.

Differences in the slopes of dose-response curves measuring pregnancy specific beta 1-glycoprotein (SP1) by means of radioimmunoassay.

Variants of pregnancy specific beta 1-glycoprotein have been described previously. These variants seem to cause artificially low levels when measured by radioimmunoassay. We demonstrate that sera with indistinct precipitates in electroimmunoassay give less steep dose-response curves in radioimmunoassay than do sera with well defined precipitates. Until parallel dose-response curves are demonstrated for all variants, previously published data must be treated with reserve.

Prediction of radiosensitivity by measurement of X-ray induced apoptosis in human blood using the comet assay.

BACKGROUND: The aim of this work was to determine whether levels of radiation-induced apoptosis in human peripheral leukocytes could be used as a predictor of radiosensitivity. MATERIALS AND METHODS: Peripheral blood was obtained from venous blood and exposed to 0-3 Gy of X-rays. Apoptosis levels were measured at 4, 24, 48 and 72 hours after exposure using the neutral comet assay. Intra-individual apoptotic response was measured using repeated blood samples from four healthy individuals. Inter-individual variation was investigated in whole blood, granulocytes and mononuclear cells from 8 radiotherapy patients (4 demonstrating a radiosensitive response and 4 demonstrating a normal response to radiation exposures). RESULTS: Amongst the four healthy individuals there was both inter- and intra-individual variation of about the same magnitude. However, when comparing the apoptotic response of the radiosensitive and normal patients, consistent trends were observed at all X-ray doses for all of the patients. CONCLUSION: This indicates that apoptosis has some potential as a predictive assay, however, large intra-individual variation exists. More studies are required to investigate the causes of intra-individual variation and how it might be minimized.

[Activation of the Ha-ras oncogene in tumors induced in mice by transplacental exposure to 7,12-dimethylbenz(a)anthracene]. / Aktivatsiia onkogena Ha-ras v opukholiakh, indutsirovannykh u myshei transplatsentarnym vozdeistviem 7,12-dimetilbenz(a)antratsena.

A study of tumors induced in mice by transplacental exposure to 7,12-dimethylbenz(a)anthracene (DMBA) alone or in combination with postnatal tissue-specific promotion showed skin and liver tumor development to be associated with cellular Ha-ras oncogene activation in a large percentage of cases. As shown by Xba I RFLP, oncogene activation was caused by T for A substitution at the second position of codon 61. The said mutation was traced in DMBA-induced tumors of the liver alone but not in spontaneous hepatomas. The results of the study showed the role of oncogene activation in cancer development to be tissue-specific.

Specific binding of phorbol esters to Friend erythroleukemia cells--general properties, down regulation and relationship to cell differentiation.

Specific and saturable binding sites for [20-3H]phorbol 12,13-dibutyrate ([3H]PDBu) were demonstrated in intact Friend erythroleukemia cells (FELC), in which inducible erythroid differentiation is reversibly inhibited by phorbol esters. The binding of [3H]PDBu to intact cells was maximal within only 15 min of incubation at 37 degrees C, after which there was a gradual decrease; binding at 4 degrees C however, was a slow process, requiring greater than 180 min for maximal binding. A Scatchard analysis showed that the dissociation constant for binding of [3H]PDBu is 8.3 nM; at saturation, approximately 1.75 x 10(5) molecules of [3H]PDBu are bound per cell. The binding of [3H]PDBu is blocked by 12-O-tetradecanoyl phorbol-13-acetate, phorbol 12,13-didecanoate, mezerein, 4-O-methyl-12-O-tetradecanoyl phorbol-13-acetate and resiniferatoxin, but not by phorbol or 4 alpha-phorbol 12,13-didecanoate. There was, in general, a good correlation between the potency of these agents in inhibiting [3H]PDBu binding and their activity in promoting tumors on mouse skin. Inducers of differentiation, such as hexamethylene bisacetamide, dimethyl sulfoxide and butyric acid, as well as inhibitors of cell differentiation, dexamethasone and local anesthetics, did not significantly block the binding of [3H]PDBu to intact FELC. When FELC were induced to differentiate with 4 mM hexamethylene bisacetamide (approximately 80% of cells were benzidine-positive), a slight decrease (10-20%) in the number of binding sites at saturation was seen, but the dissociation constant was not changed. When the cells were precultured with non-radioactive phorbol esters, a significant decrease in [3H]PDBu binding was observed, suggesting a homologous down regulation of phorbol ester receptors. Scatchard analysis indicated that the decrease in [3H]PDBu binding was due to a decrease in the number of binding sites and not to a change in affinity. Such specific phorbol ester binding sites might mediate a number of biochemical and biological effects of phorbol esters on FELC.

Acquisition of heme iron by Neisseria meningitidis does not involve meningococcal transferrin-binding proteins.

Similarities in size between hemin-binding protein 1 (HmBP1) and transferrin-binding protein 1 (TBP1) of Neisseria meningitidis suggest that these proteins are functionally homologous. However, a meningococcal mutant lacking the transferrin-binding proteins retained the capacity to acquire iron from heme and hemoglobin. In immunoblots, hyperimmune polyclonal antiserum against TBP1 did not react with HmBP1.

Inhibition of cell communication between Balb/c 3T3 cells by tumor promoters and protection by cAMP.

The effect of phorbol ester tumor promoters on the communication between individual cells in confluent culture was studied using a fluorescent dye transfer method. Cell-cell communication between mouse Balb/c 3T3 cells and between Chinese hamster V79 cells was inhibited almost completely by tumor-promoting phorbol esters, but not by nonpromoting derivatives; the effect was reversed upon removal of the promoter. Intercellular communication between Balb/c 3T3 cells, but not Chinese hamster V79 cells, was increased significantly in the presence of dbcAMP and caffeine, and these compounds counteracted the effects of tumor promoters. Inhibition of cell communication by phorbol esters appears to be receptor-mediated, since specific binding of 3H-phorbol-12,13-dibutyrate to Balb/c 3T3 cells was inhibited only by compounds that also inhibit intercellular dye transfer. A study with cycloheximide suggests that the reversible inhibition of intercellular communication by phorbol esters may not need de novo protein synthesis, while upregulation of communication by cAMP requires protein synthesis.

Continuous suppression of globin gene expression and differentiation of Friend erythroleukemia cells by phorbol 12-myristate 13-acetate (PMA) despite the loss of PMA binding sites by down regulation.

The tumor promoter phorbol 12-myristate 13-acetate (PMA) reversibly inhibits hexamethylene bisacetamide-induced terminal differentiation of Friend erythroleukemia cells (FELC). We were successful in continuously inhibiting FELC differentiation by PMA up to 125 weeks (about 240 serial passages of cells in the presence of PMA). During that period, FELC can be induced to differentiate and enter terminal cell division upon removal of PMA. PMA-mediated suppression of FELC differentiation was associated with only a low level of globin mRNA accumulation. However, a rapid accumulation of globin mRNA in the cytoplasm followed by hemoglobin accumulation occurred upon removal of PMA. A specific, saturable, high-affinity receptor for phorbol esters is present in FELC, as was shown by binding studies with [3H]phorbol 12,13-dibutyrate. A significant (80%) loss in the number of phorbol ester receptors of FELC was observed after a continuous inhibition of differentiation by PMA for as much as 125 weeks. Despite such a down regulation of phorbol ester receptors, these cells respond to PMA with a dose-response similar to that of their parent cells, which have the normal number of phorbol ester receptors. Thus, PMA can suppress reversibly the accumulation of globin-specific mRNA and terminal differentiation of FELC during prolonged periods, despite loss of receptor sites, and our results suggest that only few phorbol ester receptors may be necessary for complete inhibition of FELC differentiation by PMA.

Characterization of a human placental factor which inhibits specific binding of phorbol esters to cultured cells.

Phorbol ester receptors have been demonstrated in a variety of cells and tissues using [3H]phorbol-12,13-dibutyrate (PDBu) as a ligand. In a search for possible endogenous ligand(s) for the receptor, we used the human placenta as a source. A factor that can inhibit the binding of [3H]PDBu on different types of cells was purified (133-fold) from an extract of human placenta. This factor, PEBIF ('phorbol ester binding inhibitory factor'), is sensitive to pepsin and resistant to trypsin treatment. It is heat- and acid (pH3)-stable and can be precipitated by 80% ethanol with no loss of activity. PEBIF inhibits binding whether it is added before or after incubation of [3H]PDBu with human amniotic membrane cells (FL). Inhibition occurs at both 37 degrees C and 4 degrees C and is rapid and reversible; it does not require intact cells, since it also occurs with membrane fractions. PEBIF does not act like a binding protein for PDBu, and the kinetics of the inhibition on FL cells is non-competitive. Inhibition was also observed in rat liver cells (IAR 6) and Friend erythroleukaemia cells (FELC). Differentiation of FELC induced by hexamethylene bisacetamide can be inhibited by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) only if TPA-sensitive cells (TS 19-101) are used; no inhibition is observed with TPA-resistant cells (TR 19-9). The same is true of PEBIF. It has been shown that these two clones have about the same number of receptors, with no change of affinity; and the extent of inhibition of PDBu binding by PEBIF was similar in the two clones. Like TPA, PEBIF can increase 2-deoxyglucose uptake in mouse fibroblasts (BALB/3T3 cells). These data suggest that this physiological factor may play a role in the regulation of cell differentiation and/or in the modulation of carcinogenesis.

Prognostic value of alpha-fetoprotein radioimmunoassay in surgically treated patients with embryonal cell carcinoma of the testis.

Alpha-fetoprotein was assayed radioimmunologically in 51 samples of sera from 26 patients who had been operated for embryonal cell carcinoma of the testis. The test was found to have good prognostic value. Elevated levels were seen frequently in patients with metastase or who developed metastases. The kinetic study of alpha-fetoprotein allows us to monitor treatment efficiency, as well as to study cancer evolution.

Specific binding and biological effects of tumor promoting phorbol esters on sponges.

Sponges grown in the presence of 12-O-tetradecanoyl phorbol-13-acetate (TPA) show deep alterations of their structure and development. Their aquiferous system (flagellated cells and canals) is largely altered and the tissues show an unusually high cell density. This focalized effect of TPA on the aquiferous system seems specific and is reversible at low concentrations (100 ng/ml). A toxic, non-specific effect is also noted, particularly at high concentrations (5000 ng/ml). Using 3H-phorbol-12, 13-dibutyrate (3H-PDBu), we demonstrate a class of specific binding sites for phorbol esters in the homogenates of sponges. These binding sites have high affinity (Kd = 26.0 nM) for PDBu and at saturation about 20 pmoles of 3H-PDBu is bound per mg protein of sponge homogenates. The binding of 3H-PDBu was inhibited by other phorbol esters and their congeners, and there was a good correlation between their potency in binding inhibition and their tumor promoting activity. It is concluded that sponges have a class of specific saturable and high affinity receptors for phorbol esters and that there is a very high conservation of these receptors during evolution. Such specific binding may be responsible for subsequent biological effect of TPA on sponges.

Mean alpha-fetoprotein values of 1,333 males over 15 years by age groups.

Sera of 1,333 African, Caucasian, Chinese and Malay males over 15 years from four countries were randomly assayed for alpha-fetoprotein (AFP) by the radioimmunoassay. The average AFP level was 2.97 IU/ml (+ 2 SD = 8.78, -2 SD = 1.00) which can be compared with previously published figures ranging from 2.3 to 1.2 ng/ml. Average values increased with age and the upper limit (mean + 2 SD) in the over 64 years age group was close to 17 IU/ml. The use of international units should facilitate the comparison of results between laboratories. The present data can help in determining whether an AFP value is "normal" and when AFP levels of certain follow-up patients revert to normal.

alpha-Fetoprotein levels in normal individuals. Relative stability over time.

Samples of serum were collected at 6- to 12-month intervals in two groups of healthy Africans and the amount of AFP measured by the radioimmunological method. The amounts present were found to remain fairly constant over time. The significance of this stability is discussed with particular reference of the highest levels of AFP observed in normal individuals in relation to primary liver carcinoma and the potential use of the method as a tool for early detection purposes.