Sensory cues of predation risk generate sex-specific changes in neural activity and behavior, but not hormones, in Trinidadian guppies.

How an organism responds to risk depends on how that individual perceives such risk. Integrating cues from multiple sensory modalities allows individuals to extract information from their environment, and whether and how the brain and body respond differently to different sensory cues can help reveal mechanistic decision-making processes. Here, we assessed neural, hormonal, and behavioral responses to different sensory cues of predation risk in Trinidadian guppies (Poecilia reticulata). Adult guppies were assigned to one of four treatment groups: control, visual, olfactory, and both sensory cues combined from a natural predator, the pike cichlid (Crenicichla alta), for 2 h. We found no difference in glucocorticoid response to any cue. However, we found behavioral and neural activation responses to olfactory-only cues. In addition, we found a sex by treatment effect, where males showed greater changes in neural activation in brain regions associated with avoidance behavior, while females showed greater changes in neural activation in regions associated with social behavior and memory, mirroring sex by treatment differences in behavioral antipredator responses. Altogether, our results demonstrate that single and combinatory cues may influence risk-taking behavior differently based on sex, suggesting that perception and integration of cues can cascade into sex differences in behavior.

Outcome of HIV-infected Pregnant Women and Their Offspring in Barbados: A Five-year Study.

OBJECTIVES: To describe the outcome of HIV-infected pregnant women and their offspring during a five-year period. METHODS: The medical records of HIV-infected pregnant women who delivered between January 2007 and December 2011 and their HIV-exposed infants were reviewed. Demographics, outcome of pregnancy and infants, and clinic attendance were analysed. Data were entered on a Microsoft Excel spreadsheet. RESULTS: One hundred and forty-three women, aged 17-45 years (mean 27.3 years), were included in the study with 143 pregnancies and 142 pregnancy outcomes being recorded. One woman migrated before delivery. There were 122 live births and 18 (13%) terminations: 13 (9%) elective and five (4%) spontaneous. There was one ectopic pregnancy and one stillbirth. One hundred and twenty-two (85%) women were unmarried. Women were prescribed highly active antiretroviral therapy for prevention of mother-to-child transmission from the time of booking, apart from those opting for terminations or those who had spontaneous abortions. For clinic follow-up, 105 (73%) had regular attendance, 30 (21%) defaulted and could not be located despite intense tracking, four attended irregularly, and one refused to attend clinic. Four (3%) migrated after delivery. Two (1%) mothers died during the period of study. Two successive DNA polymerase chain reaction tests done within four months of age did not substantiate any cases of infant infection. CONCLUSION: This study revealed that there was a good outcome and compliance with follow-up of HIV-infected pregnant women and their offspring.

Diagnostic value of sentinel lymph node biopsy in head and neck cancer: a meta-analysis.

This study aimed to evaluate the diagnostic reliability of sentinel lymph node biopsy in patients with squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, and larynx by reviewing the published literature. A systematic literature review was performed using MEDLINE from 1970 to 2011. With Boolean search strings, search terms included sentinel node, supraglottic, supraglottis, tongue, head and neck, oral, pharynx, laryngeal, and larynx. Additional studies were identified through article references. Duplicate data and articles were excluded based on treating institution and study inclusion time period. Additional studies were excluded if the head and neck subsite or tumor stage was not specifically identified or if the sentinel lymph node biopsy occurred in previously treated necks. All patients had sentinel lymph node biopsy performed followed by a concurrent neck dissection. Twenty-six studies met our inclusion criteria (n = 766 patients). The pooled sensitivity and negative predictive value of SLNB for all head and neck tumors was 95 % (95 % CI 91-99 %) and 96 % (95 %CI 94-99 %), respectively. The overall sensitivity and negative predictive value of SLNB in the subset of oral cavity tumors (n = 631) was 94 % (95 % CI 89-98 %) and 96 % (95 % CI 93-99 %), respectively. One-hundred percent of oropharyngeal (n = 72), hypopharyngeal (n = 5), and laryngeal (n = 58) tumor sentinel lymph biopsy results correlated with subsequent neck dissections giving a negative predictive value of 100 %, showing that, sentinel lymph node biopsy is a valid diagnostic technique to correctly stage regional metastases in patients with head and neck squamous cell carcinoma.

Human homologue of the Drosophila melanogaster lats tumour suppressor modulates CDC2 activity.

We have previously used mosaic flies to screen for tumour suppressors or negative regulators of cell proliferation. The cellular composition of these flies resembles that of cancer patients who are chimaeric individuals carrying a small number of mutated somatic cells. One of the genes we identified is the large tumour suppressor gene, lats (also known as wts), which encodes a putative serine/threonine kinase. Somatic cells mutant for lats undergo extensive proliferation and form large tumours in many tissues in mosaic adults. Homozygous mutants for various lats alleles display a range of developmental defects including embryonic lethality. Although many tumour suppressors have been identified in Drosophila melanogaster, it is not clear whether these fly genes are directly relevant to tumorigenesis in mammals. Here, we have isolated mammalian homologues of Drosophila lats. Human LATS1 suppresses tumour growth and rescues all developmental defects, including embryonic lethality in flies. In mammalian cells, LATS1 is phosphorylated in a cell-cycle-dependent manner and complexes with CDC2 in early mitosis. LATS1-associated CDC2 has no mitotic cyclin partner and no kinase activity for histone H1. Furthermore, lats mutant cells in Drosophila abnormally accumulate cyclin A. These biochemical observations indicate that LATS is a novel negative regulator of CDC2/cyclin A, a finding supported by genetic data in Drosophila demonstrating that lats specifically interacts with cdc2 and cyclin A.

Mice deficient of Lats1 develop soft-tissue sarcomas, ovarian tumours and pituitary dysfunction.

The lats gene has been identified as a tumour suppressor in Drosophila melanogaster using mosaic screens. Mosaic flies carrying somatic cells that are mutant for lats develop large tumours in many organs. The human LATS1 homologue rescues embryonic lethality and inhibits tumour growth in lats mutant flies, demonstrating the functional conservation of this gene. Biochemical and genetic analyses have revealed that LATS1 functions as a negative regulator of CDC2 (ref. 3). These data suggest that mammalian LATS1 may have a role in tumorigenesis. To elucidate the function of mammalian LATS1, we have generated Lats1-/- mice. Lats1-/- animals exhibit a lack of mammary gland development, infertility and growth retardation. Accompanying these defects are hyperplastic changes in the pituitary and decreased serum hormone levels. The reproductive hormone defects of Lats1-/- mice are reminiscent of isolated LH-hypogonadotropic hypogonadism and corpus luteum insufficiency in humans. Furthermore, Lats1-/- mice develop soft-tissue sarcomas and ovarian stromal cell tumours and are highly sensitive to carcinogenic treatments. Our data demonstrate a role for Lats1 in mammalian tumorigenesis and specific endocrine dysfunction.

Apricoxib upregulates 15-PGDH and PGT in tobacco-related epithelial malignancies.

BACKGROUND: Despite focused research in conventional therapies and considerable advances in the understanding of the molecular carcinogenesis of head and neck squamous cell carcinoma (HNSCC), the 5-year survival rate for patients with advanced disease remains ∼15-20%. The major causes of HNSCC-related deaths are cervical node and distant metastasis. E-cadherin has a key role in epithelial intercellular adhesion and its downregulation is a hallmark of epithelial-mesenchymal transition (EMT), which is associated with invasion, metastasis, and poor prognosis. Epithelial-mesenchymal transition is the major mechanism responsible for mediating invasiveness and metastasis of epithelial cancers. Recently, we reported the role of E-cadherin transcriptional repressors in the inflammation-induced promotion of EMT in HNSCC, which is mediated by COX-2. These findings suggest that therapies targeting the cyclooxygenase pathway may diminish the propensity for tumour metastasis in HNSCC by blocking the PGE2-mediated induction of E-cadherin transcriptional repressors. METHODS: Herein, we evaluate the efficacy of the COX-2 inhibitor, apricoxib, in HNSCC cell lines. Apricoxib is effective in preventing tumour cell growth in three-dimensional, and anchorage-independent growth assays, as well as decreasing the capacity for tumour cell migration. RESULTS: Herein, we evaluate the efficacy of the COX-2 inhibitor, apricoxib, in HNSCC cell lines. Apricoxib is effective in preventing tumour cell growth in three-dimensional, and anchorage-independent growth assays, as well as decreasing the capacity for tumour cell migration. Treatment of HNSCC cells with apricoxib also causes greater upregulation of E-cadherin and Muc1 expression and downregulation of vimentin, as compared with celecoxib treatment. This has significant implications for targeted chemoprevention and anti-cancer therapy because E-cadherin expression has been implicated as a marker of sensitivity to epidermal growth factor receptor tyrosine kinase inhibitor and other therapies. We show for the first time the molecular mechanisms underlying the efficacy of apricoxib in HNSCC cells. CONCLUSION: In addition to reversing EMT via inhibition of COX-2, apricoxib upregulates 15-prostaglandin dehydrogenase and the prostaglandin transporter, thereby reducing the levels of active PGE2 by both suppressing its synthesis and increasing its catabolism. These findings have significant implications for metastasis and tumour progression in HNSCC.

Maternal transmission of human immunodeficiency virus escape mutations subverts HLA-B57 immunodominance but facilitates viral control in the haploidentical infant.

Expression of HLA-B57 is associated with restricted replication of human immunodeficiency virus (HIV), but the mechanism for its protective effect remains unknown. If this advantage depends upon CD8 T-cell recognition of B57-restricted epitopes, mother-to-child transmission of escape mutations within these epitopes could nullify its protective effect. However, if the B57 advantage is largely mediated by selection for fitness-attenuating viral mutations within B57-restricted epitopes, such as T242N in TW10-Gag, then the transmission of such mutations could facilitate viral control in the haploidentical infant. We assessed the consequences of B57-associated mutations on replication capacity, viral control, and clinical outcome after vertical transmission in 13 mother-child pairs. We found that expression of HLA-B57 was associated with exceptional control of HIV during infancy, even when mutations within TW10 and most other B57-restricted epitopes were transmitted, subverting the natural immunodominance of HLA-B57. In contrast, most B57-negative infants born to B57-positive mothers progressed rapidly to AIDS. The presence of T242N led to a reproducible reduction in viral fitness, as demonstrated by in vitro assays using NL4-3 constructs encoding p24 sequences from individual mothers and infants. Associated compensatory mutations within p24-Gag were observed to reverse this impairment and to influence the propensity of T242N to revert after transmission to B57-negative hosts. Moreover, primary failure to control viremia was observed in one infant to whom multiple compensatory mutations were transmitted along with T242N. These parallel in vivo and in vitro data suggest that HLA-B57 confers its advantage primarily by driving and maintaining a fitness-attenuating mutation in p24-Gag.

How to Investigate the Origins of Novelty: Insights Gained from Genetic, Behavioral, and Fitness Perspectives.

Biologists are drawn to the most extraordinary adaptations in the natural world, often referred to as evolutionary novelties, yet rarely do we understand the microevolutionary context underlying the origins of novel traits, behaviors, or ecological niches. Here we discuss insights gained into the origins of novelty from a research program spanning biological levels of organization from genotype to fitness in Caribbean pupfishes. We focus on a case study of the origins of novel trophic specialists on San Salvador Island, Bahamas and place this radiation in the context of other rapid radiations. We highlight questions that can be addressed about the origins of novelty at different biological levels, such as measuring the isolation of novel phenotypes on the fitness landscape, locating the spatial and temporal origins of adaptive variation contributing to novelty, detecting dysfunctional gene regulation due to adaptive divergence, and connecting behaviors with novel traits. Evolutionary novelties are rare, almost by definition, and we conclude that integrative case studies can provide insights into this rarity relative to the dynamics of adaptation to more common ecological niches and repeated parallel speciation, such as the relative isolation of novel phenotypes on fitness landscapes and the transient availability of ecological, genetic, and behavioral opportunities.

Como Investigar as Origens da Novidade: Ideias Obtidas a Partir de Perspectivas da Genética, do Comportamento e de Fitness (How to Investigate the Origins of Novelty: Insights Gained from Genetic, Behavioral, and Fitness Perspectives) Biólogos são atraídos pelas adaptações mais extraordinárias do mundo natural, muitas vezes chamdas de novidades evolutivas, mas raramente entendemos o contexto microevolutivo subjacente às origens de novas características, novos comportamentos ou nichos ecológicos. Aqui discutimos ideias obtidas sobre as origens da novidade evolutiva a partir de um programa de pesquisa abrangendo níveis biológicos de organização de genótipo para fitness em pupas do Caribe. Nós nos concentramos em um estudo de caso sobre as origens de novos especialistas tróficos na ilha de São Salvador, Bahamas, e colocamos essa radiação no contexto de outras radiações rápidas. Destacamos questões que podem ser abordadas sobre as origens da novidade evolutiva em diferentes níveis biológicos, como medir o isolamento de novos fenótipos no cenário adaptativo, localizando as origens espaciais e temporais da variação adaptativa que contribuem para a novidade evolutiva, detectando a regulação gênica disfuncional devido à divergência adaptativa, e conectando comportamentos com novas características. As novidades evolutivas são raras, quase por definição, e concluímos que estudos de caso integrativos podem fornecer ideias sobre essa raridade em relação à dinâmica de adaptação a nichos ecológicos mais comuns e especiação paralela repetitiva, como o relativo isolamento de novos fenótipos em cenários adaptativos e a disponibilidade transitória de oportunidades ecológicas, genéticas, e comportamentais. Translated to Portuguese by G. Sobral (gabisobral@gmail.com).

Lack of bladder tumor promoting activity in rats fed sodium saccharin in AIN-76A diet.

Sodium saccharin (NaSac) fed as 5% of Prolab diet promotes bladder tumor carcinogenesis in male F344 rats initiated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) fed as 0.2% of the diet for 4 weeks. NaSac also increases urothelial proliferation if fed for short periods in Prolab diet, but no increased proliferation is seen if it is fed for up to 10 weeks in AIN-76A semisynthetic diet, even at levels as high as 7.5% of the diet. To determine whether NaSac as part of an AIN-76A diet has promoting activity, groups of approximately 30 male, 5-week-old F344 rats were fed AIN-76A diet containing (a) 0.2% FANFT for 4 weeks followed by 5% NaSac for 100 weeks; (b) 0.2% FANFT followed by control diet; or (c) control diet followed by 5% NaSac. Bladder tumor incidences were 10, 23, and 0%, respectively. When fed in Prolab diet, 0.2% FANFT for 4 weeks followed by NaSac or control diet for 100 weeks resulted in bladder tumor incidences of 40 and 17%, respectively. Groups of rats fed 0.1 or 0.2% FANFT for 1 or 2 weeks followed by 5% NaSac or control diet for 100 weeks had bladder tumor incidences of 0 to 7%. These data demonstrate that NaSac does not promote bladder cancer in male rats if fed in AIN-76A diet. Other studies suggest that this is due to the low urinary pH in rats fed AIN-76A diet.

Effect of L-tryptophan excess and vitamin B6 deficiency on rat urinary bladder cancer promotion.

To further evaluate the role of tryptophan and vitamin B6 in bladder carcinogenesis, male Fischer 344 rats were fed 0.2% N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) in semipurified diet or were given semipurified diet alone for 4 weeks. One week later, rats from each group were assigned for the remainder of the experiment to one of four experimental diets, labeled as follows: group 1, control semipurified; group 2, L-tryptophan excess (2%); group 3, vitamin B6-deficient (1.0 mg/kg diet); or group 4, L-tryptophan excess, plus vitamin B6-deficient diet. All surviving rats were killed at 80 weeks of the experiment. Throughout the study, body weights were reduced in the groups fed FANFT and, at 70 and 80 weeks, body weights were reduced in the groups given tryptophan excess. The incidence of urinary bladder carcinoma was highest in the group treated with FANFT, followed by diet with control tryptophan and vitamin B6 levels (40%). The disease incidence was reduced in the vitamin B6-deficient group (13%) and of an intermediate range in the groups fed a tryptophan excess with or without vitamin B6 deficiency (28-29%). Tumors at other sites were greatest in number in FANFT-treated rats fed vitamin B6-deficient diet with excess tryptophan and were significantly fewer in FANFT-treated rats fed vitamin B6-deficient diet alone. Animals given diet deficient in vitamin B6 consistently had depressed levels of alanine aminotransferase activity and plasma pyridoxyl phosphate. FANFT pretreatment decreased alanine aminotransferase activities in rats in some groups and the feeding of tryptophan had variable effects on alanine aminotransferase and plasma pyridoxyl phosphate levels. Urinary tryptophan metabolites were influenced by all treatments, but the results did not correlate with tumor yields. Urinary bladder ornithine decarboxylase activity was not altered in vitamin B6-deficient female rats. These results do not support the hypothesis that increased dietary L-tryptophan promotes bladder carcinogenesis in rats, but other dietary factors might modify the process following FANFT initiation.

Acrolein initiates rat urinary bladder carcinogenesis.

Acrolein, a reactive, alpha,beta-unsaturated aldehyde which is ubiquitous in the environment, forms DNA adducts, is mutagenic, and is teratogenic. However, studies have not indicated a carcinogenic effect in rodent bioassays. Since it is present in cigarette smoke and is the toxic metabolite of cyclophosphamide with respect to the urinary tract, we investigated the possibility that acrolein might have carcinogenic activity toward the rat urinary bladder. We also evaluated whether it possessed initiating and/or promoting activity. To evaluate initiating activity, acrolein was administered at a dose of 2 mg/kg i.p. twice a week for 6 weeks followed by uracil as 3% of the diet for 20 weeks and then control diet for 6 weeks. N-[4-(5-Nitro-2-furyl)-2-thiazolyl]formamide (FANFT) as 0.2% of the diet followed by uracil was used as a positive control, and a negative control group was administered solvent control (water) i.p. during the 6-week initiation period followed by uracil. Acrolein followed by uracil produced an incidence of 18 of 30 rats (60%) with papilloma compared to 8 of 30 rats (27%) treated with solvent control followed by uracil. FANFT followed by uracil produced an incidence of 70% carcinomas and 30% papillomas, clearly indicating that it is a much more potent initiating agent than acrolein. Acrolein for 6 weeks followed by control diet produced no tumors. To evaluate promoting activity, groups of rats were fed FANFT for 6 weeks followed by acrolein. Acrolein administered during the initial 6 weeks and continued for the second phase of the experiment (to evaluate complete carcinogenic activity) resulted in severe toxicity. Administration of acrolein had to be terminated after 21 weeks of the experiment. The animals were maintained for 53 weeks of the experiment without further chemical treatment, and there was no evidence of papilloma or carcinoma development. This study clearly indicates that acrolein has initiating activity for the urinary bladder when administered by i.p. injection to the male F344 rat, but toxicity precluded evaluation of its promoting or complete carcinogenic activity.

An examination of the elastic properties of tissue-mimicking phantoms using vibro-acoustography and a muscle motor system.

Tissue hardness, often quantified in terms of elasticity, is an important differentiating criterion for pathological identity and is extensively used by surgeons for tumor localization. Delineation of malignant regions from benign regions is typically performed by visual inspection and palpation. Although practical, this method is highly subjective and does not provide quantitative metrics. We have previously reported on Vibro-Acoustography (VA) for tumor delineation. VA is unique in that it uses the specific, non-linear properties of tumor tissue in response to an amplitude modulated ultrasound beam to generate spatially resolved, high contrast maps of tissue. Although the lateral and axial resolutions (sub-millimeter and sub-centimeter, respectively) of VA have been extensively characterized, the relationship between static stiffness assessment (palpation) and dynamic stiffness characterization (VA) has not been explicitly established. Here we perform a correlative exploration of the static and dynamic properties of tissue-mimicking phantoms, specifically elasticity, using VA and a muscle motor system. Muscle motor systems, commonly used to probe the mechanical properties of materials, provide absolute, quantitative point measurements of the elastic modulus, analogous to Young's modulus, of a target. For phantoms of varying percent-by-weight concentrations, parallel VA and muscle motor studies conducted on 18 phantoms reveal a negative correlation (p < - 0.85) between mean signal amplitude levels observed with VA and calculated elastic modulus values from force vs. indentation depth curves. Comparison of these elasticity measurements may provide additional information to improve tissue modeling, system characterization, as well as offer valuable insights for in vivo applications, specifically surgical extirpation of tumors.

A descriptive study of HIV-infected long-term surviving children in Barbados--a preliminary report.

OBJECTIVES: To describe the clinical and immunologic characteristics of human immunodeficiency virus type-1 (HIV-1)-infected children surviving to more than eight-years of age (long-survivors) before the introduction of antiretroviral therapy. METHODS: This report is based on all the long-term survivors from a prospective cohort of HIV-infected children born to HIV-positive women in Barbados during 1986-1995. Infants born to HIV-infected women were enrolled into this cohort at birth or at the time of diagnosis of HIV exposure in the postnatal period and followed-up at regular intervals. RESULTS: From a cohort of 44 HIV-infected children, 17 (38.6%) children survived to the age of eight years and beyond and were classified as long-term survivors. Median age of the sixteen long-term surviving children alive at the time of this report was 12 years (age range 8 - 16.7 years). At the age of 8 years, 17.6% of these children remained asymptomatic. Nine (52.9%) children had no immunodeficiency (CD4 counts >500 cells x 10(6)/L). Of the 16 long-term surviving children who were alive and had a median follow-up of 4.1 years (range 0.1 year to 8.5 years) after their eighth birthday, 37.5% had a CD4 cell count greater than 500 cells x 10(6)/L and had either no symptoms or only mild symptoms of HIV infection and were therefore categorized as the long-term non-progressors. CONCLUSIONS: In a small cohort of HIV-infected children, in the absence of antiretroviral therapy, only about one-third survived beyond eight years of age. On further follow-up of these long-term surviving children, over one-third had a slow rate of disease progression.

Evaluation of epidermal cell kinetics following freezing or wounding of mouse skin and their potential as initiators of carcinogenesis.

It has been shown that abrasion, and consequent regenerative hyperplasia, acts as a promoting agent in mouse skin carcinogenesis. The present experiments were designed to evaluate the possibility that ulceration and its consequent regeneration might also act as initiators. Female Sencar mice were used, and ulceration was induced either by the application of a frozen rod or by incision of the skin of the back. The time course of the ulceration, regeneration, and repair of the mouse skin following ulceration by either method was evaluated utilizing morphologic and autoradiographic techniques. The labeling index of the epidermis, using [3H]-thymidine and autoradiography, reached a maximum level 7 days after ulceration and the epidermal hyperplasia was most pronounced at days 7-14. The potential initiating activity of freeze ulceration or incision was evaluated by performing these procedures on 7-week-old female Sencar mice followed by promotion with 12-O-tetradecanoylphorbol-13-acetate (TPA) applied twice a week to the ulcerated areas, 5.2 micrograms in each application. Extending the total experimental observation to 1 year indicated that freeze ulceration and incision did not initiate carcinogenesis in the mouse skin when promoted with TPA.

Long term dose response study of N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide-induced urinary bladder carcinogenesis.

The effect of dose was evaluated for the bladder carcinogenicity of N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide (FANFT). The chemical was fed to male weanling F344 rats for 30 weeks followed by 74 weeks of control diet. The incidences of bladder carcinoma were 100, 100, 87, 0, 0 and 0% for doses of 0.2, 0.1, 0.05, 0.01, 0.005 and 0.001%, respectively. There was an inverse relationship between dose and latency period. There was no increased incidence of tumors of other tissues.

Effect of aspirin on N-[4-(5-nitro-2-furyl)-2-thiazolyl]-formamide-induced epithelial proliferation in the urinary bladder and forestomach of the rat.

The co-administration of aspirin with N-[4-(5-nitro-2-furyl)-2-thiazolyl]-formamide (FANFT) to rats resulted in a reduced incidence of FANFT-induced bladder carcinomas but a concomitant induction of forestomach tumors. An autoradiographic study was performed on male F-344 rats fed diet containing FANFT at a level of 0.2% and/or aspirin at a level of 0.5% to evaluate the effect of aspirin on the increased cell proliferation induced by FANFT in the forestomach and bladder. FANFT-induced cell proliferation in the bladder was significantly suppressed by aspirin co-administration after 4 weeks but not after 12 weeks. In the forestomach, and also in the liver, aspirin did not affect the FANFT-induced increase in labeling index. The present results are consistent with the carcinogenicity experiment suggesting that different mechanisms are involved in FANFT carcinogenesis in the bladder and forestomach, and that aspirin's effect on FANFT in the forestomach is not due to an irritant effect associated with increased cell proliferation. Also, there appears to be an adaptation by the rats to the chronic ingestion of aspirin.

A comparison of the effects of sodium saccharin in NBR rats and in intact and castrated male F344 rats.

High doses of sodium saccharin (NaSac) increase proliferation in the bladder of the rat, with a male preponderance. The possibility that alpha 2u-globulin is involved in its mechanism of action was evaluated by feeding it at 7.5% of the diet to NCI-Black-Reiter (NBR) male rats, which do not synthesize liver-derived alpha 2u-globulin. NaSac affected urinary parameters similarly in F344 and NBR male rats, but NBR rats consumed more water leading to greater urinary volume. NaSac produced less proliferation in NBR than in intact F344 rats, with intermediate changes in castrated F344 males, which had intermediate urinary alpha 2u-globulin levels.

Dietary effects of ortho-phenylphenol and sodium ortho-phenylphenate on rat urothelium.

Ortho-phenylphenol (OPP) and sodium ortho-phenylphenate (NaOPP) are pesticides used commercially in the food industry that have been shown to be carcinogenic to rat urothelium. Dietary administration of 1.25% OPP or 2.0% NaOPP caused increased incidences of urothelial hyperplasia and eventually caused tumors in male F344 rats, with NaOPP apparently having a more potent effect. In other studies, various sodium salts such as saccharin and ascorbate enhanced bladder carcinogenesis, although the acid forms of these salts did not. In studies with high dietary doses of these sodium salts, an amorphous precipitate was produced in the urine; precipitate formation was pH dependent. In previous experiments in which high doses of OPP were fed for up to 17 weeks, severe hyperplasia of the urothelium was produced, but without the formation of an urinary amorphous precipitate, calculi, or abnormal microcrystalluria. In addition, we found no evidence of OPP-DNA adduct formation in the urothelium. The present study was conducted to determine if feeding NaOPP * 4 H(2)0 to male F344 rats as 2.0% of the diet resulted in the formation of an amorphous precipitate in the urine, and if NaOPP caused an increased mineral concentration in the urine and/or kidneys. NaOPP administration produced a higher urinary pH than did OPP fed as 1.25% of the diet. Neither amorphous precipitate nor other solids were observed in the urine of the OPP or NaOPP-treated rats, and urinary calcium concentrations in the treated groups were similar to control. OPP and NaOPP had similar proliferative effects on rat urothelium after 10 weeks of treatment by light microscopy, scanning electron microscopy (SEM), and bromodeoxyuridine (BrdU) labeling indices. The results of this study indicate that formation of abnormal urinary solids is not part of the mechanism by which OPP or NaOPP exert their effects on the rat bladder epithelium.

RNA profiling of cell-free saliva using microarray technology.

Saliva, like other bodily fluids, has been used to monitor human health and disease. This study tests the hypothesis that informative human mRNA exists in cell-free saliva. If present, salivary mRNA may provide potential biomarkers to identify populations and patients at high risk for oral and systemic diseases. Unstimulated saliva was collected from ten normal subjects. RNA was isolated from the cell-free saliva supernatant and linearly amplified. High-density oligonucleotide microarrays were used to profile salivary mRNA. The results demonstrated that there are thousands of human mRNAs in cell-free saliva. Quantitative PCR (Q-PCR) analysis confirmed the present of mRNA identified by our microarray study. A reference database was generated based on the mRNA profiles in normal saliva. Our finding proposes a novel clinical approach to salivary diagnostics, Salivary Transcriptome Diagnostics (STD), for potential applications in disease diagnostics as well as normal health surveillance.

Evaluation of nitrofurantoin on the two stages of urinary bladder carcinogenesis in the rat.

The possibility that nitrofurantoin is a complete carcinogen or is an initiator or promoter of urinary bladder carcinogenesis was evaluated in male weanling F344 rats. No increase in tumor incidence was observed in rats fed nitrofurantoin at a level of 0.187% of the diet for 2 years compared to a control group. Also, no evidence of bladder initiating activity by nitrofurantoin was observed using sodium saccharin (5% of the diet) as a promoter, and no promoting activity was observed when nitrofurantoin was fed after initiation by N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (0.2% of the diet for 4 weeks). In a second experiment, nitrofurantoin (at a dose of 0.187% of the diet) was administered for 6 weeks to rats with a rapidly proliferating bladder epithelium following freeze ulceration, and then the rats were treated with 5% sodium saccharin in the diet for 98 weeks. In additional rats, labelling index following [3H]thymidine injection, determined after 12 weeks of feeding nitrofurantoin, was not increased above control levels in the urinary bladder, stomach, duodenum, or liver. Metabolism of nitrofurantoin by prostaglandin H synthase (PHS) was examined using solubilized ram seminal vesicle microsomes. The rate of nitrofurantoin metabolism by PHS was much less than that observed with benzidine, and the proportion of total metabolite bound to protein was also much less than that with benzidine. These results are consistent with previous reports describing the lack of effect of nitrofurantoin on urinary bladder carcinogenesis.