The nature of the language input affects brain activation during learning from a natural language.

Artificial language studies have demonstrated that learners are able to segment individual word-like units from running speech using the transitional probability information. However, this skill has rarely been examined in the context of natural languages, where stimulus parameters can be quite different. In this study, two groups of English-speaking learners were exposed to Norwegian sentences over the course of three fMRI scans. One group was provided with input in which transitional probabilities predicted the presence of target words in the sentences. This group quickly learned to identify the target words and fMRI data revealed an extensive and highly dynamic learning network. These results were markedly different from activation seen for a second group of participants. This group was provided with highly similar input that was modified so that word learning based on syllable co-occurrences was not possible. These participants showed a much more restricted network. The results demonstrate that the nature of the input strongly influenced the nature of the network that learners employ to learn the properties of words in a natural language.

Fatty acids and their prostaglandin derivatives: inhibitors of proliferation in aortic smooth muscle cells.

Prostaglandins are synthesized from eicosa-8,11,14-trienoic acid and eicosa-5,8,11-14-tetraenoic acid by smooth muscle cell cultures from guinea pig aorta. Production is inhibited by indomethacin. The precursor fatty acids and their prostaglandin derivatives inhibit proliferation of the cell cultures. The relative availability of fatty acids for prostaglandin biosynthesis may represent a control mechanism for cell proliferation.

Alterations of enzymes associated with plasma membranes and cellular organelles during infection of CV-1 cells with Yaba tumor poxvirus.

The formation of cellular aggregates (foci) in CV-1 cells following infection with Yaba tumor poxvirus is dependent upon cell passage level, temperatue of incubation, and calcium concentration in the medium. Resistance of older cells can be reversed by maintaining calcium at 0.1 mM or by adding cortisone acetate (1 mug/ml), hydrocortisone, or estradiol-17beta to the cultures. In susceptible cells, foci formation was inhibited slightly by methyltestosterone and inhibited completely by dexamethasone, aldosterone and progesterone. Activities and patterns of enzymes associated with cytoplasmic membranes (alkaline phosphatase, mononucleotidase, and Na+-K+-adenosine triphosphatase) and lysosomes (beta-glucuronidase and acid phosphatase) of the younger susceptible and the older resistant CV-1 cells differed. These differences apparently occurred in concert with phenotypic changes in the membranes that reduced the mobility of older resistant cells. In susceptible culture, unifected cells migrated to the infected cell and participated in foci formation. Reduction of the calcium content to 0.1 mM apparently removed some of the constraints on mobility of the resistant cells. Although the hormones may have had a similar effect, the changes in enzyme patterns indicated basic alterations in protein synthesis. The development of resistance to foci formation occurred between the 45th and 50th passage level. Hormonal reversal of this resistance resulted in enzyme profiles that reflected the pattern of young susceptible cells.

Neoplastic transformation of human epithelial cells in vitro after exposure to chemical carcinogens.

Human foreskin epithelial cells were transformed to an anchorage-independent state of growth (in soft agar) and neoplasia (invasion of chick embryonic skin in vitro). Aflatoxin B1, N-methyl-N'-nitro-N-nitrosoguanidine, propanesultone, beta-propiolactone, or ultraviolet absorbance at 254 nm were used successfully as carcinogens. These foreskin epithelial cells, like human foreskin fibroblasts, were readily transformed when treated in S phase but, unlike the transformed fibroblasts, expression of cellular neoplasia did not require an extended period of time in culture. The invasive features of the transformed human epithelial cells in chick embryonic skin in vitro simulated squamous cell carcinoma.

Chromosome alterations associated with in vitro exposure of human fibroblasts to chemical or physical carcinogens.

Normal human foreskin fibroblasts treated in vitro with a chemical carcinogen or irradiated with ultraviolet light subsequently acquired anchorage independent growth and an extended but finite capacity for exponential growth. All cell lines were derived from cells recovered from colonies that had grown in semisolid medium; cell lines originally treated with a chemical carcinogen produced nodules after s.c. inoculation into nude mice. G-banding analysis of 10 cell lines (including one ultraviolet light line) revealed that seven were chromosomally abnormal with structural and numerical chromosome alterations, one was characterized by a consistent trisomy, and the other two were normal diploid. Structural alterations consisted of chromosome deletions, translocations, and partial chromosome duplications. Although no common structural or numerical abnormality was detected, several structural alterations were observed involving chromosomes 1, 7, 11, and 22, where fgr, erb-B, H-ras-1, and sis protooncogenes, respectively, are located. In one cell line trisomy 17 was a unique chromosome alteration. The induction of chromosome changes may have influenced the proliferative capacity of the treated cells relative to nontreated cells. However, the two cell lines without detectable chromosome changes also had an increased proliferative life span, suggesting that other submicroscopic genetic alterations may have affected cell multiplication. Although carcinogen induced chromosome abnormalities may represent a step in the process of neoplastic development, additional genetic and/or epigenetic changes, are required for indefinite growth and the expression of malignancy.

Biochemical activation of aryl hydrocarbon hydroxylase activity, cellular distribution of polynuclear hydrocarbon metabolites, and DNA damage by polynuclear hydrocarbon products in human cells in vitro.

Carcinogenic polynuclear hydrocarbons [7,12-dimethylbenzanthracene, 3-methylcholanthrene, and benzo(a)pyrene] were added to human skin fibroblast cell cultures. Only benzo(a)pyrene at 10 microgram/ml or above induced mixed-function hydroxylase activity, altered cell proliferation kinetics, and caused DNA damage as measured by altered grain count and bromodeoxyuridine incorporation. 3-Methylcholanthrene at concentrations as high as 15 microgram/ml was ineffective. 7,12-Dimethylbenzanthracene at 6 microgram/ml or above induced mixed-function oxygenase and stimulated DNA synthesis and cell proliferation, but at those concentrations little or no cytotoxicity or DNA damage was detected. The noncarcinogenic analogs 6,8,12-trimethylbenzanthracene, 5-fluorodimethylbenzanthracene, anthracene, and phenanthrene had no detectable effect on the human cells. It was concluded that benzo(a)pyrene can initiate all the biochemical events in human cells probably necessary to initiate transformation of human cells in vitro.

Influence of glucocorticoid, estrogen, and androgen hormones on transformation of human cells in vitro by feline sarcoma virus.

Infection of human foreskin cells (D-550) by the Snyder-Theilen strain of feline sarcoma virus produced small but countable foci and demonstrated "single-hit" dose-response kinetics. Significant quantitative and qualitative enhancement of focus formation was observed when the glucocorticoid hormones, dexamethasone, hydrocortisone, cortisol acetate, and prednisolone were added to cell cultures (1.0 mug/ml) 24 hr postinfection. However, aldosterone, while inducing qualitatively larger foci, did not bring about a quantitative enhancement in total foci number. By contrast, 17beta-estradiol, progesterone, cortisone acetate, methyltestosterone, and estrone elicited little or no effect on focus induction by Snyder-Theilen feline sarcoma virus. Evidence is suggestive of a posttranscriptional effect possibly modulating viral genome expression resulting in an increased efficiency of viral transformation, and an increased proliferation of transformed cells.

Isolation and characterization of a monoclonal antibody specific for epithelial cells.

Monoclonal antibodies were generated to antigens on human foreskin keratinocytes to identify epithelial-specific molecules. Spleen cells from BALB/c mice, immunized with membrane preparations from primary explants of foreskin epithelial cells, were fused with the NS-1 mouse myeloma line. Hybridoma supernatants were screened for the desired immunological reactivity using enzyme-linked immunosorbant binding assays. Hybridomas secreting antibodies reacting with epithelial cells, but not fibroblasts or lymphocytes, were cloned by limiting dilution, and two stable clones producing immunoglobulin M K antibodies were selected for study. Evaluation of fixed paraffin-embedded human tissue by an indirect immunoperoxidase technique revealed that the antibodies bound most strongly to normal stratified squamous and transitional epithelium, and squamous and transitional cell carcinomas. Antibodies from the cloned hybridomas also reacted with primary cell cultures of foreskin keratinocytes, pulmonary epithelium, fetal liver, and amnion cells, but not with primary cultures of nonepithelial cells. Further testing by enzyme-linked immunosorbent assays revealed that the antibodies reacted with some long-term cell lines derived from epithelial tumors. Nonepithelial cell lines were not stained by the antibodies. Indirect immunofluorescent studies indicated that staining was confined to the cell surface. These antibodies may prove useful in studies of differentiation markers of human epithelial cells.

Inhibition of S37 ascites cell amino acid transport systems by alpha-chloromethylketone analogs.

Alanine chloromethylketone and leucine chloromethylketone were synthesized and their effects on amino acid transport in sarcoma 37 mirone ascites tumor (S37) cells were studied. Alanine chloromethylketone preincubation weakly inhibited system A. Leucine chloromethylketone preincubation strongly inhibited both amino acid transport systems L and A. Leucine chloromethylketone was also a competitive inhibitor of leucine transport. Labeled leucine chloromethylketone was concentrated by S37 cells. Leucine chloromethylketone preincubation inhibition was concentration dependent and partial protection of transport was afforded by leucine. Steady-state retention of amino acids was decreased more than the initial velocity of transport by leucine chloromethylketone preincubation. Glutathione was also depleted. Labeled leucine chloromethylketone was incorporated in a plasma membrane protein fraction comigrating on a DEAE-cellulose column (DE52) with gamma-glutamyltranspeptidase activity. There was a modest increase in vital staining after treatment of S37 cells with leucine chloromethylketone, and glucose uptake was also inhibited. Whilst several effects occur during treatment of S37 cells with leucine chloromethylketone, it is suggested than one prominent effect is alkylation of amino acid transport system components.

Duration of antibacterial treatment for uncomplicated urinary tract infection in women.

BACKGROUND: Uncomplicated urinary tract infection (UTI) is a common disease, occurring frequently in young sexually active women. In the past, seven day antibiotic therapy was recommended while the current practice is to treat uncomplicated UTI for three days. OBJECTIVES: TO compare the efficacy and safety of three-day antibiotic therapy to multi-day therapy (five days or longer) on relief of symptoms and bacteriuria at short-term and long-term follow-up. SEARCH STRATEGY: The Cochrane Library (Issue 1, 2004), the Cochrane Renal Group's Register of trials (July 2003), EMBASE (January 1980 to August 2003), and MEDLINE (January 1966 to August 2003) were searched. We scanned references of all included studies and contacted the first or corresponding author of included trials and the pharmaceutical companies. SELECTION CRITERIA: Randomised controlled trials comparing three-days oral antibiotic therapy with multi-day therapy (five days and longer) for uncomplicated cystitis in 18 to 65 years old non-pregnant women without signs of upper UTI. DATA COLLECTION AND ANALYSIS: Data concerning bacteriological and symptomatic failure rates, occurrence of pyelonephritis and adverse effects were extracted independently by two reviewers. Relative risk (RR) and their 95% confidence intervals (CI) were estimated. Outcomes were also extracted by intention-to-treat analysis whenever possible. MAIN RESULTS: Thirty-two trials (9605 patients) were included. For symptomatic failure rates, no difference between three-day and 5-10 day antibiotic regimen was seen short-term (RR 1.06, 95% CI 0.88 to 1.28) and long-term follow-up (RR 1.09, 95% CI 0.94 to 1.27). Comparison of the bacteriological failure rates showed that three-day therapy was less effective than 5-10 day therapy for the short-term follow-up, however this difference was observed only in the subgroup of trials that used the same antibiotic in the two treatment arms (RR 1.37, 95% CI 1.07 to 1.74, P = 0.01). This difference was more significant at long-term follow-up (RR 1.43, 95% CI 1.19 to 1.73, P = 0.0002). Adverse effects were significantly more common in the 5-10 day treatment group (RR 0.83, 95% CI 0.74 to 0.93, P = 0.0010). Results were consistent for subgroup and sensitivity analyses. AUTHORS' CONCLUSIONS: Three days of antibiotic therapy is similar to 5-10 days in achieving symptomatic cure during uncomplicated UTI treatment, while the longer treatment is more effective in obtaining bacteriological cure. In spite of the higher rate of adverse effects, treatment for 5-10 days could be considered for treatment of women in whom eradication of bacteriuria is important.

Comparative stages of expression of human squamous carcinoma cells and carcinogen transformed keratinocytes.

The mouse monoclonal antibody OSU 22-3 was prepared using cells from a squamous cell carcinoma (SCC) as an immunogen. This antibody reacts with an antigen found on squamous cell carcinomas but does not react with normal keratinocytes. This antibody and two antibodies that react with normal keratinocytes were used as markers of malignant and normal phenotypes. These markers were used to evaluate several spontaneous and carcinogen initiated SCC tumors and to identify the expression of an antigen associated with a malignant phenotype. A variety of subpopulations in carcinogen initiated tumors and spontaneous SCC tumors were noted. The subpopulations that reacted only with MoAb OSU 22-3 exhibited features of anchorage independent growth and cellular invasiveness, and formed progressively growing tumors in nude mice. Other SCC spontaneous tumor cell subpopulations reacted with the antibodies associated with normal keratinocytes. These cells did not proliferate in vitro and did not form tumors in the nude mouse. There were other carcinogen transformed cells which reacted with MoAb OSU 22-3 but not with the antibodies associated with normal keratinocytes. These cells exhibited anchorage independent growth and cellular invasiveness but did not form tumors in nude mice. We conclude from this work that human SCC tumors contain multiple cell populations. These cell populations have varied growth properties and express surface antigens that may indicate their malignant vigor. Carcinogen transformed keratinocytes do exhibit some of the characteristics of SCC tumor phenotypes but not the property of malignant progressively growing cells on a routine and consistent basis. This feature is transiently and inconsistently expressed in a surrogate host by populations prepared from spontaneous SSC tumors.

Benzo[a]pyrene diol epoxide I modification of DNA in human skin xenografts.

Human skin xenografts were established on the subscapular area of skin of nude (nu/nu NIH-Swiss background) mice. When treated with benzo[a]pyrene diol epoxide I (BPDE I), specific carcinogen-DNA adducts were formed. Separation and identification of these adducts by the 32P-postlabeling technique indicated that the 7R- and 7S-BPDE I-dpGp adducts were the major adducts. Xenografts pretreated with either allantoin or anthralin showed an increase in the major 7R- and 7S-BPDE I adducts compared to only BPDE I treatment. Likewise, we observed an increase in the quantity of different minor adducts. The ratios between the minor and major adducts in the pretreated grafts remained consistent with the ratio in the grafts treated with BPDE I only. We conclude that these modulators induce cells in the xenograft to enter S phase of the cell cycle. Moreover, we observed that these compounds altered the quantity of the minor carcinogen-DNA adducts without altering the overall ratios between the major 7R- and 7S-BPDE I-dpGp adducts and the minor carcinogen-DNA adducts.

Physiological concentrations of prolactin can promote the growth of human breast tumor cells in culture.

There is only indirect evidence at present to suggest a role for PRL in either the genesis or progression of human breast cancer. Here, we report the results of experiments in primary cultures of breast tumor cells from a hyperprolactinemic breast cancer patient who had an elevated mean 24-h PRL concentration but a normal diurnal variation of PRL release. The effects of PRL and GH on the growth of the dispersed cells from the breast tumor was evaluated in monolayer culture using a recently developed microculture technique. Pharmacological quantities of GH produced significant increases in the number of population doublings of the breast tumor cells. Also, PRL concentrations present in the patient's circulation were demonstrated to significantly increase the number of population doublings of the breast tumor cells obtained in primary cultures. Thus, physiological concentrations of PRL stimulated the growth of breast tumor cells from this premenopausal patient.

Inhibition of carcinogen-induced cellular transformation of human fibroblasts by drugs that interact with the poly(ADP-ribose) polymerase system. Initial evidence for the development of transformation resistance.

Two types of interactions of 13 drugs with human fibroblasts were determined: I50 of nuclear poly(ADP-ribose) polymerase, as assayed with isolated nuclei in vitro, and the non-toxic concentration of drugs that prevented carcinogen-induced cell transformation of intact fibroblasts (RCF1). In general, RCF1 was much lower than I50, and one antitransformer did not inhibit the enzyme in vitro, indicating that low-affinity enzyme inhibitory sites appear to play no role in the mechanism of prevention of cell transformation. Two enzyme inhibitors, caffeine and 1-methylnicotinamide, exhibited no antitransforming activity. Benzamide when applied in population doubling 1 induced resistance to cell transformation in population doubling 6 by carcinogens added at this stage.

Synthetic sulfur-containing amino acids. Inhibition of transport systems in S37 ascites tumor cells.

The preparation of a series of synthetic sulfur-containing amino acids is described. These compounds included heterocyclic analogues of L-cysteine, DL-norcysteine, and DL-homocysteine. The amino acids were assessed for their ability to inhibit the neutral amino acid transport systems of the Sarcoma 37 ascites tumor cell and their inhibitions were compared with those of L-methionine and L-ethionine. Transport studies indicated that the amino acids synthesized were capable of inhibiting the uptake of [3H]-L-histidine in the S37 cell.

Conditions for transformation of human fibroblast cells: an overview.

Low passage (low population doubling) human diploid fibroblasts respond to carcinogen and mutagen treatment, with higher passage level human cells remaining refractory to the insult. A cell cycle dependency for an optimize response to the carcinogen of competent responsive low passage cells is associated with early S phase. The process of fixation of the damage in dividing young cells could be more efficient due to intrinsic sensitivity of young cells towards carcinogens. However, specific DNA-carcinogen adduct analysis does not reveal any qualitative or quantitative difference. These low passage carcinogen initiated human cells progress towards the expression of a malignant phenotype. There is little evidence to suggest that these abnormal phenotypes exhibit an infinite lifespan using the selection pressures for isolation of the transformed phenotypes. However, the lifespan of these treated cells is extended beyond those of the untreated cells. In conclusion, criteria can be established to measure the expression of progression of these carcinogen initiated cells towards a malignant phenotype.

Analysis of intracellular distribution and binding of benzo[alpha]pyrene in human diploid fibroblasts.

Previous work with low passage synchronized human foreskin fibroblast cell populations has indicated that benzo[alpha]pyrene (BP) can induce a carcinogenic event [3]. BP additionally has shown to damage DNA in log-arithmically growing low passage cultures [9]. High passage cells, on the other hand, seem to be refractory to transformation by BP, even though this agent can induce DNA damage, similar to that seen in low passage cells. When low passage cells were treated with BP, the initial binding of the hydrocarbon was primarily to a cytoplasmic protein complex of molecular weight 12,500 while in high passage cells, a major portion of BP was bound to protein complex of molecular weight 200,000. High-pressure liquid chromatography (HPLC) profiles of ethyl acetate extractable fractions from the BP-cytoplasmic protein complexes of low and high passage cells demonstrated that the majority of the BP remained unmetabolized. When nuclei were isolated from low and high passage cells prior to the HPLC analysis, the major component (90%) was again unmetabolized BP. The results suggest selective attachment of BP to different cytoplasmic protein complexes of logarithmically growing human diploid fibroblast cells dependent on the passage level of the cells.

Enhanced expression of the 8-oxo-7,8-dihydrodeoxyguanosine triphosphatase gene in human breast tumor cells.

The expression of the 8-oxo-7,8-dihydrodeoxyguanosine triphosphatase (8-oxo-dGTPase) gene in human breast tumors was evaluated at the level of the single cell to better understand how breast tumor cells regulate expression in response to oxidative stress. Compared to normal breast ductal cells, the level of 8-oxo-dGTPase expression in the breast tumor cells increased from non-detectable levels in normal breast to expression in 30-85% of the tumor cells in individual tumors. There was no significant association between 8-oxo-dGTPase expression and tumor grade and metastatic malignancy. The upregulation of 8-oxo-dGTPase was not directly linked to the expression of cyclins D1 and D3, estrogen receptor, p53, Ki-67 and c-erbB-2, which are genes involved in cell cycle regulation and tumor growth. The elevated expression of 8-oxo-dGTPase in human breast ductal carcinoma cells appears to be a general characteristic of breast tumors and may provide the tumor cell with a cellular defense mechanism to prevent the incorporation of 8-hydroxy-deoxyguanosine during DNA replication.

A comparative study of dimethylhydrazine regioisomers and the methylazoxymethanol metabolite of 1,1- and 1,2-dimethylhydrazine in relation to transformation in human fibroblasts.

Comparative analysis of the cytotoxicity, transformation efficiency, induction of alkali labile sites (ALS) and DNA methylation in human foreskin fibroblasts was carried out with two dimethylhydrazine (DMH) regioisomers (1,1-DMH and 1,2-DMH) and the acetate (A) derivative of the metabolite methylazoxymethanol (MAM) of 1,2-DMH. Effective ED50 cytotoxic doses for MAMA, 1,1-DMH and 1,2-DMH were 0.056, 6.83 and 6.30 mM, respectively. MAMA and 1,1-DMH were more effective transformers than 1,2-DMH. However, methylation of purines accounted for less than 1% of the total radiolabel associated with DNA for all 3 agents. 1,2-DMH, 1,1-DMH and MAMA induced O6MeGua/N7MeGua ratio of 0.04, 0.32 and 0.18, respectively. Only MAMA induced measurable alkali labile lesions at transforming doses. These results suggest that other mechanisms may play a role in the initiation of transformation events by hydrazine analogues.

[14C]leucine chloromethylketone interaction with sarcoma 37 cell plasma membrane components.

Leucine chloromethylketone labeling of viable S37 cells was preferential for the plasma membrane fraction. The pattern of radiolabeling of the plasma membrane proteins was time dependent. After 5 min the radiolabel was localized with glutamyl transpeptidase, and subsequently with other physiologically active proteins as a function of time after incubation. Labeling of proteins was temperature dependent and incubation of viable S37 cells with the radiolabeled substrate at 0 degrees C yielded little or no radioactivity localized in the plasma membrane. The molecular weight of one radiolabeled substrate--membrane protein complex was estimated on sodium dodecyl sulfate polyacrylamide gel electrophoresis to be between 100,000-200,000.