Simple design criteria and efficiency of hydrodynamic vortex separators.

Vortex separators still draw attention from specialists investigating the process of removing particles suspended in liquids. The devices are locally applied for waste water treatment in different systems - from storm waste water sewerage to water circulation in fish ponds. However, the methods for separator design presented in the literature are questionable. The paper presents two simple and functional criteria that were employed to construct a laboratory test stand. The test results gave positive feedback on the efficiency of vortex separators.

Application of microbial assay for risk assessment biotest in evaluation of toxicity of human and veterinary antibiotics.

The microbial assay for risk assessment (MARA) is a multispecies, growth inhibition microplate toxicity test with 11 microorganisms individually lyophilized in microplate wells. The microbial species representing wide diversity, generated 11 microbial toxic concentration (MTC) values were obtained giving a unique "toxic fingerprint" profile of the test sample. The toxicity of 14 antibiotics was evaluated with the MARA test. The fingerprints for each group of antibiotics differ, indicating a particular toxic profile. Tetracyclines were the most toxic antibacterials with the minimum MTC value of 3.6 µg L(-1). In the group of tetracyclines the order of the three most sensitive microbial strains was the same 2 > 6 > 7. Quinolones affected the most sensitive strain(s) at concentrations of 12-75 µg L(-1). The MARA bioassay exhibited different spectra of toxic responses to microbial strains for the first and second generation quinolones. However, for first generation quinolones strain 6 was substantially more sensitive than the other microorganisms, while second generation quinolones were most toxic to strain 3, followed by 6 then 4. In this instance, the three strains belong to two different phylogenetic groups-strain 3 is γ-proteotype and strains 4 and 6 are ß-proteotype.

Application of a microbiotests battery for complete toxicity assessment of rivers.

Acute hazard classification based on selected microbiotests was proposed to assess and compare the toxicity of rivers including surface-water, sediment and soil from floodplains. No direct relationship between the classification of pollution for surface-water based on physical-chemical parameters and proposed acute hazard classification based on organisms' sensitivity was observed. The quality of water according to hazard classification was better than in the mandatory classification of pollution, with the domination of Class II (slight acute hazard). The samples of sediment and soil were more toxic and represented Class II or Class III (acute hazard). The results indicated a need to complete the mandatory monitoring of surface-water in rivers with biological monitoring with toxicity assessment of rivers including water, sediment and soil from floodplains based on acute hazard classification. This integral approach enables a complete evaluation of the toxicity of aquatic life together with an estimation of negative changes in river systems.

Involvement of both syn- and anti-dihydrodiol-epoxides in the binding of 7, 12-dimethylbenz(a)anthracene to DNA in mouse embryo cell cultures.

7,12-Dimethylbenz(a)anthracene (DMBA):deoxyribonucleoside adducts, from enzymic hydrolyses of DNA from mouse embryo cells exposed in culture to [3H]DMBA, can be separated into two fractions on the basis of whether or not they bind to the phenyl boronic acid residues of Servacel DHB. This suggests that these two fractions of adducts are derived from anti and syn bay-region dihydrodiol-epoxides, respectively. The fluorescence spectra and interactions of the major components of these two fractions with borate ions substantiate this interpretation. These findings indicate that both syn- and anti-dihydrodiol-epoxides make a substantial contribution to DMBA binding to DNA in mouse embryo cells. For a given mouse embryo cell preparation, the relative contributions of each of these dihydrodiol-epoxides to DNA binding did not vary substantially with DMBA dose, with incubation time with DMBA, or in growing versus confluent cultures, although there were differences between one cell preparation and another.

Products of binding of 7,12-dimethylbenz(a)anthracene to DNA in mouse skin.

7,12-Dimethylbenz(a)anthracene (DMBA):deoxyribonucleoside-adducts, from enzymatic hydrolysis of DNA from mouse skin exposed to [3H]DMBA in vivo, were analyzed by reverse-phase high-pressure liquid chromatography. Double-labeling studies showed that the adducts were qualitatively identical to those formed in mouse embryo cell cultures. These have been tentatively identified as bay-region anti-dihydrodiol epoxide: deoxyguanosine- and :deoxyadenosine adducts and a bay-region syn-dihydrodiol epoxide:deoxyadenosine-adduct (where the terms syn and anti define dihydrodiol-epoxides wherein the benzylic hydroxyl group and epoxide oxygen are cis or trans to one another, respectively). The relative amounts of individual adducts did not vary substantially with time or with the sex of the mice. However, the syn-dihydrodiol-epoxide:deoxyadenosine-adduct did increase with dose and constituted as much as 40% of the total DNA binding at high doses of DMBA. This is in contrast to the much lower (2 to 3%) levels of binding to deoxyadenosine residues in mouse skin reported for the less potent tumor initiator benzo(a)pyrene. The greater reactivity of DMBA with deoxyadenosine residues in mouse skin may play a role in determining its greater tumor initiating potential.

Increased frequency of spontaneous skin tumors in transgenic mice which overexpress ornithine decarboxylase.

Ornithine decarboxylase, a critical regulatory enzyme for polyamine biosynthesis, is highly inducible by growth-promoting stimuli in mouse epidermis but the enzyme level is only transiently elevated due to rapid turnover of the protein. Here we report that constitutive overexpression of the enzyme in the skin of transgenic mice causes several phenotypic abnormalities. Effects observed include development of dermal follicular cysts, excessive skin wrinkling, enhanced nail growth, alopecia, and spontaneous tumor development. These results indicate that up-regulation of polyamine biosynthesis can profoundly disturb skin homeostasis and alter susceptibility to neoplastic development.

The mRNA-binding protein HuR promotes hypoxia-induced chemoresistance through posttranscriptional regulation of the proto-oncogene PIM1 in pancreatic cancer cells.

Previously, it has been shown that pancreatic ductal adenocarcinoma (PDA) tumors exhibit high levels of hypoxia, characterized by low oxygen pressure (pO2) and decreased O2 intracellular perfusion. Chronic hypoxia is strongly associated with resistance to cytotoxic chemotherapy and chemoradiation in an understudied phenomenon known as hypoxia-induced chemoresistance. The hypoxia-inducible, pro-oncogenic, serine-threonine kinase PIM1 (Proviral Integration site for Moloney murine leukemia virus 1) has emerged as a key regulator of hypoxia-induced chemoresistance in PDA and other cancers. Although its role in therapeutic resistance has been described previously, the molecular mechanism behind PIM1 overexpression in PDA is unknown. Here, we demonstrate that cis-acting AU-rich elements (ARE) present within a 38-base pair region of the PIM1 mRNA 3'-untranslated region mediate a regulatory interaction with the mRNA stability factor HuR (Hu antigen R) in the context of tumor hypoxia. Predominantly expressed in the nucleus in PDA cells, HuR translocates to the cytoplasm in response to hypoxic stress and stabilizes the PIM1 mRNA transcript, resulting in PIM1 protein overexpression. A reverse-phase protein array revealed that HuR-mediated regulation of PIM1 protects cells from hypoxic stress through phosphorylation and inactivation of the apoptotic effector BAD and activation of MEK1/2. Importantly, pharmacological inhibition of HuR by MS-444 inhibits HuR homodimerization and its cytoplasmic translocation, abrogates hypoxia-induced PIM1 overexpression and markedly enhances PDA cell sensitivity to oxaliplatin and 5-fluorouracil under physiologic low oxygen conditions. Taken together, these results support the notion that HuR has prosurvival properties in PDA cells by enabling them with growth advantages in stressful tumor microenvironment niches. Accordingly, these studies provide evidence that therapeutic disruption of HuR's regulation of PIM1 may be a key strategy in breaking an elusive chemotherapeutic resistance mechanism acquired by PDA cells that reside in hypoxic PDA microenvironments.

Several galactosyltransferase activities are associated with mouse chromosome 17.

Indirect evidence suggests that some major histocompatibility complex (MHC) proteins are glycosyltransferases. No sequence or mapping information is available for transferases, although ganglioside variations in mice are linked to the H-2 complex on chromosome 17, and one galactosyltransferase activity on mouse sperm varies with T/t complex genotypes, also on chromosome 17. In the present experiments, diploid and trisomy 17 mouse embryos were assayed for four different galactosyltransferase activities. The same preparations were assayed for isocitrate dehydrogenase (Id-1, chromosome 1) and glyoxalase-1 (Glo-1, chromosome 17). Galactosyltransferase specific activities in trisomy 17 embryos are almost 1.5 times higher than in diploid embryos. The correlation between galactosyltransferase activities and chromosome 17 dosage indicates that the structural or regulatory gene for these enzymes are located on chromosome 17.

Ineffectiveness of human chorionic gonadotropin in weight reduction: a double-blind study.

Our investigation was designed to retest the hypothesis of the efficacy of human chorionic gonadotropin (HCG) on weight reduction in obese women in a clinic setting. We sought to duplicate the Asher-Harper study (1973) which had found that the combination of 500 cal diet and HCG had a statistically significant benefit over the diet and placebo combination as evidenced by greater weight loss and decrease in hunger. Fifty-one women between the ages of 18 and 60 participated in our 32-day prospective, randomized, double-blind comparison of HCG versus placebo. Each patient was given the same diet (the one prescribed in the Asher-Harper study), was weighed daily Monday through Saturday and was counselled by one of the investigators who administered the injections. Laboratory studies were performed at the time of initial physical examinations and at the end of the study. Twenty of 25 in the HCG and 21 of 26 patients in the placebo groups completed 28 injections. There was no statistically significant difference in the means of the two groups in number of injections received, weight loss, percent of weight loss, hip and waist circumference, weight loss per injections, or in hunger ratings. HCG does not appear to enhance the effectiveness of a rigidly imposed regimen for weight reduction.

Cell-specific ecdysone-inducible expression of FLP recombinase in mammalian cells.

The ability of site-specific recombinases, like FLP and Cre, to catalyze alterations in genomic DNA is well established, whereas their application to genetic engineering strategies has been restricted because of the inability to temporally regulate their expression and subsequent recombination events in specific populations of cells. We describe a regulatory system for ecdysone-controlled expression of FLP recombinase. Furthermore, we demonstrate that ecdysone-induced, FLP-mediated site-specific recombination events can be targeted to specific cells. This system can be applied to cell-lineage studies as well as to the design of gene-therapy strategies, particularly in stem cells.

Ultrastructural histochemical localization of acid phosphatase in salivary glands of Drosophila melanogaster.

The ultrastructural histochemical localization of acid phosphatase in salivary glands of third instar larvae of Drosophila melanogaster has been studied. Using Gomori's lead phosphate method for acid phosphatase detection, the optimal incubation time in the reaction medium was determined to be 30 min. When glands having wild-type acid phosphatase activity are incubated for this time, deposition of the final reaction product is observed in essentially every lysosome and artifactual staining is minimal.

Effects of butylated hydroxyanisole and butylated hydroxytoluene on 7,12-dimethylbenz[a]anthracene-DNA adduct formation in mouse embryo cell cultures.

Neither butylated hydroxyanisole (BHA) nor butylated hydroxytoluene (BHT) significantly reduced overall 7,12-dimethylbenz[a]anthracene (DMBA)--DNA adduct formation in mouse embryo cell cultures. However, analysis of DMBA--DNA adducts by Servacel DHB chromatography and high-pressure liquid chromatography showed that treatment of cells with BHA, but not with BHT, resulted in a decreased contribution from the syn bay region dihydrodiol epoxide to overall binding.

Breast biopsy techniques and adequacy of margins.

The change toward breast-conserving surgery for cancer has altered the role of the initial biopsy. We retrospectively analyzed two methods, traditional excisional biopsy (n = 47) and lumpectomy (n = 44) to evaluate their usefulness as the initial procedure for breast-conserving surgery. Lumpectomy required more time (mean +/- SEM, 53 +/- 3 minutes) than traditional biopsy (37 +/- 2 minutes). Margins were verified by microscopic examination to be clear in 73% of the patients in the lumpectomy group and in only 17% of patients in the traditional biopsy group. Patients in the lumpectomy group subsequently underwent more axillary dissections than patients in the traditional biopsy group (31% vs 4%, respectively) and fewer modified radical mastectomies (49% vs 71%, respectively). A correlation between extensive intraductal components and positive margins was found in the lumpectomy group. These data suggest that as the initial biopsy method, lumpectomy more often provides adequate margins and may decrease the number of subsequent procedures on the breast for breast-conserving surgery.

Biotransformation in monkey brain: coupling of sulfation to glutathione conjugation.

Phenol sulfotransferase (PST, EC 2.8.2.1) and glutathione-S-transferase (GST, EC 2.5.1.18), the phase II biotransformation enzymes inactivate many exo- and endogenous compounds. The effect of PST substrates (catecholamines, simple phenols, selected phenolic drugs) and PST products (phenolic sulfates) on GST activity was investigated to identify possible interactions between sulfation and glutathione conjugation in the brain. Two soluble forms of PST and two forms of GST were isolated from monkey (Rhesus macacus) brain cortex. Catecholamines, hypertensive and hypotensive drugs which are sulfated by monkey brain PSTs slightly inhibit the activity of brain GSTs. The greatest inhibitory effect was observed with neurotoxic compounds such as 6-OHDA and manganese. The commonly used analgesic drugs inhibit both GST forms. These enzymes are also inhibited by phenacetin, the precursor of paracetamol, and prototype salicylates such as sodium salicylate and acetylsalicylic acid. The effect of simple phenols and their sulfated metabolites on GST activity varies. The obtained results point to a possible interaction between sulfation and glutathione conjugation in vivo since many physiologically, therapeutically and toxicologically active compounds which are sulfated by brain phenol sulfotransferases may be bound by brain glutathione-S-transferases. These compounds may lose their activity (on being bound to GST) and expose the brain to the toxic electrophiles (by decreasing GST activity).

Study on the immunological heterogeneity of Clostridium botulinum B type toxin.

The toxins prepared by dialysis-culture method from proteolytic (P) and nonproteolytic (NP) strains of C. botulinum were different. NP toxins from 3 strains (American, Japanese and Polish) showed a higher activation ratio, lower protein nitrogen content, and lower neutralization rate compared with P toxins. Antitoxic titers of rabbit anti-P and especially anti-NP sera were always higher when titrated with NP than with P toxins. The values of the regression coefficients in neutralization experiments were not dependent on the sera preparations, but only on the toxins. The difference between the common slope b for several sera tested against P and NP toxins was statistically significant. A difference between the passive protection of mice against P and NP toxins was observed only at very low levels of unitage. These results suggested immunological heterogeneity of B type botulinum toxin. However, for practical purposes, it is not necessary to supplement therapeutic antitoxin with a factor which neutralizes NP toxin.

2-Chloro-2'-deoxyadenosine (2-CdA) combined with cyclosporine A successfully prevents rejection of fetal brain stem allograft in rabbits.

Allografts of brain stem from 20-day-old fetuses to nucleus caudatus of adult rabbits were performed. To prevent graft rejection immunosuppression with 2-CdA and cyclosporine A was transiently induced. Graft survival were assessed by histological and electrophysiological techniques. Both morphological (synaptogenesis, myelinization) and functional (generation of rhythmic neuronal activity) signs of graft maturation were found after nine weeks. The data suggest that transient immunosuppression used is sufficient to induce tolerance to neural graft, and no interference with maturation of implanted fetal tissue occurs.

K6/ODC transgenic mice as a sensitive model for carcinogen identification.

Ornithine decarboxylase (ODC), an important enzyme in the polyamine biosynthetic pathway, is aberrantly regulated in many epithelial tumors of rodents and humans. In murine skin, it has been shown that ODC overexpression provides a sufficient condition for tumor promotion. Therefore, we hypothesized that K6/ODC transgenic mice in which ODC overexpression was targeted to hair follicle keratinocytes might provide a sensitive model for identifying genotoxic carcinogens. Ten known carcinogens or noncarcinogens have been tested in the model so far and results are highly concordant with 2-year rodent bioassays (100% concordant). More importantly, each of two chemicals tested that is recognized as a human carcinogen was identified as a carcinogen in K6/ODC transgenic mice. In addition, 7, 12-dimethylbenz(a)anthracene (DMBA) dose response studies indicated that even at a very low dose, 2 nmol, a high percentage of mice (50%) had already developed tumors 8 weeks after treatment. We conclude that the K6/ODC transgenic mouse model is very sensitive to topical application of genotoxic carcinogens and could therefore be a useful mouse model for carcinogen identification and chemical risk assessment.

Relation of lymph-node metastasis to histopathologic appearance in oral cavity and oropharyngeal carcinoma: a case series and literature review.

A number of histopathologic parameters in squamous cell carcinoma of the oral cavity and oropharynx have been identified as having a statistically significant correlation with regional lymph-node metastasis. These parameters have been inconsistent and not readily reproducible. In an attempt to confirm these parameters, a retrospective analysis of 22 patients with T1 to T4 squamous cell carcinoma of the oral cavity and oropharynx was performed. Initially, these patients were managed with either wide local excision or surgical excision of the primary tumor combined with radical neck dissection. There was a minimum of 3 years of follow-up. Chi-square contingency tables and Fisher's Exact Test were used to correlate histopathologic parameters with lymph-node metastasis. Statistically significant correlations were found for tumor thickness and inflammatory infiltrate.

Efficacy and cost-effectiveness of multihole fine-needle aspiration of head and neck masses.

To determine whether the specimen from fine-needle aspiration (FNA) biopsy of head and neck masses has greater diagnostic accuracy when using multihole needles than when using conventional, single-hole needles, we did a prospective, randomized, single-blinded study comparing diagnoses obtained using both types of needles in FNA biopsies of head and neck masses. Eighty-eight patients served as their own controls and had 91 FNA biopsies with both multihole and single-hole, 22-gauge needles. Order of biopsy was randomized and was unknown to the cytopathologist. No statistically significant differences were noted in quantity of specimen material obtained, quality of fixation, or diagnostic value between the multihole and conventional needle. We found no advantage in using the more costly multihole needle in FNA biopsy of head and neck masses.

Inhibitory effect of the antioxidant butylated hydroxyanisole on the activation of the carcinogen benzo(a)pyrene.

The effect of the antioxidant butylated hydroxyanisole (BHA) on benzo(a)pyrene (BP) metabolites binding to DNA, percentage of diols and phenols in the total amount of BP metabolites extracted to organic solvent, were studied in : incubation mixture of rat liver microsomes, cultured mouse embryo cells, human skin, and human lymphocytes. The amount of BP metabolites bound to DNA in mouse embryo cells and human skin decreased in the presence of BHA. No effect was found in human lymphocytes. Percent of phenols increased in mouse embryo cell cultures; percent of diols decreased in cultures of human skin and lymphocytes.