Prepubertal ovarian inhibition of Light/Dark Box exploration and novel object investigation in juvenile Siberian hamsters.

The overwhelming majority of research on the role of gonadal hormones in behavioral development has focused on perinatal, pubertal, or adult life stages. The juvenile period has been overlooked because it is thought to be a time of gonadal quiescence. In the present study, we tested whether prepubertal gonadectomy impacts the behavior of male and female juvenile hamsters on the Light/Dark Box, Novel Object, and Social Approach tests (Experiment 1) and compared these findings to those obtained after adult gonadectomy (Experiment 2). Prepubertal ovariectomy increased exploration (i.e. time spent in the light zone of the Light/Dark Box) and novel object investigation of juveniles indicating an inhibitory role for the juvenile ovary; social approach was unaffected. In contrast, adult ovariectomy and castration (both prepubertal and adult) had no effect on any behavioral measure. Experiment 3 tested whether rearing hamsters in a short day length (SD), which delays puberty in this species, extends the interval of juvenile ovarian inhibition on exploration and novelty seeking. We also tested whether provision of estradiol reverses the effects of prepubertal ovariectomy. Hormonal manipulations and behavioral tests of Experiment 3 were conducted at ages when long day-reared hamsters are adult (as in Experiment 2), but SD-reared hamsters remain reproductively immature. Ovariectomy again increased exploration in the SD-reared juveniles despite the older age of surgery and testing. Estradiol treatment had no effect. These findings reveal a novel role for the juvenile ovary in exploration and novelty seeking that is unlikely to be mediated exclusively by estradiol.

Viral rescue of magnocellular vasopressin cells in adolescent Brattleboro rats ameliorates diabetes insipidus, but not the hypoaroused phenotype.

Dysregulated arousal often accompanies neurodevelopmental disorders such as attention deficit hyperactivity disorder and autism spectrum disorder. Recently, we have found that adolescent homozygous Brattleboro (Hom) rats, which contain a mutation in the arginine vasopressin (AVP) gene, exhibit lower behavioral arousal than their heterozygous (Het) littermates in the open field test. This hypoaroused phenotype could be due to loss of AVP in magnocellular cells that supply AVP to the peripheral circulation and project to limbic structures or parvocellular cells that regulate the stress axis and other central targets. Alternatively, hypoarousal could be a side effect of diabetes insipidus - polydipsia and polyuria seen in Hom rats due to loss of AVP facilitation of water reabsorption in the kidney. We developed a viral-rescue approach to "cure" magnocellular AVP cells of their Brattleboro mutation. Infusion of a recombinant adeno-associated virus (rAAV) containing a functional Avp gene and promoter (rAAV-AVP) rescued AVP within magnocellular cells and fiber projections of the paraventricular nucleus of the hypothalamus (PVN) of male and female adolescent Hom rats. Furthermore, water intake was markedly reduced, ameliorating the symptoms of diabetes insipidus. In contrast, open field activity was unaffected. These findings indicate that the hyporaoused phenotype of adolescent Hom rats is not due to the loss of AVP function in magnocellular cells or a side effect of diabetes insipidus, but favors the hypothesis that central, parvocellular AVP mechanisms underlie the regulation of arousal during adolescence.

Functionally distinct roles for different miR-155 expression levels through contrasting effects on gene expression, in acute myeloid leukaemia.

Enforced expression of microRNA-155 (miR-155) in myeloid cells has been shown to have both oncogenic or tumour-suppressor functions in acute myeloid leukaemia (AML). We sought to resolve these contrasting effects of miR-155 overexpression using murine models of AML and human paediatric AML data sets. We show that the highest miR-155 expression levels inhibited proliferation in murine AML models. Over time, enforced miR-155 expression in AML in vitro and in vivo, however, favours selection of intermediate miR-155 expression levels that results in increased tumour burden in mice, without accelerating the onset of disease. Strikingly, we show that intermediate and high miR-155 expression also regulate very different subsets of miR-155 targets and have contrasting downstream effects on the transcriptional environments of AML cells, including genes involved in haematopoiesis and leukaemia. Furthermore, we show that elevated miR-155 expression detected in paediatric AML correlates with intermediate and not high miR-155 expression identified in our experimental models. These findings collectively describe a novel dose-dependent role for miR-155 in the regulation of AML, which may have important therapeutic implications.

Extracellular Tau Oligomers Produce An Immediate Impairment of LTP and Memory.

Non-fibrillar soluble oligomeric forms of amyloid-ß peptide (oAß) and tau proteins are likely to play a major role in Alzheimer's disease (AD). The prevailing hypothesis on the disease etiopathogenesis is that oAß initiates tau pathology that slowly spreads throughout the medial temporal cortex and neocortices independently of Aß, eventually leading to memory loss. Here we show that a brief exposure to extracellular recombinant human tau oligomers (oTau), but not monomers, produces an impairment of long-term potentiation (LTP) and memory, independent of the presence of high oAß levels. The impairment is immediate as it raises as soon as 20 min after exposure to the oligomers. These effects are reproduced either by oTau extracted from AD human specimens, or naturally produced in mice overexpressing human tau. Finally, we found that oTau could also act in combination with oAß to produce these effects, as sub-toxic doses of the two peptides combined lead to LTP and memory impairment. These findings provide a novel view of the effects of tau and Aß on memory loss, offering new therapeutic opportunities in the therapy of AD and other neurodegenerative diseases associated with Aß and tau pathology.

Risk assessment of wandering behavior in mild dementia.

OBJECTIVE: This prospective longitudinal study aims to determine the risk factors of wandering-related adverse consequences in community-dwelling persons with mild dementia. These adverse consequences include negative outcomes of wandering (falls, fractures, and injuries) and eloping behavior. METHODS: We recruited 143 dyads of persons with mild dementia and their caregivers from a veteran's hospital and memory clinic in Florida. Wandering-related adverse consequences were measured using the Revised Algase Wandering Scale - Community Version. Variables such as personality (Big Five Inventory), behavioral response to stress, gait, and balance (Tinetti Gait and Balance), wayfinding ability (Wayfinding Effectiveness Scale), and neurocognitive abilities (attention, cognition, memory, language/verbal skills, and executive functioning) were also measured. Bivariate and logistic regression analyses were performed to assess the predictors of these wandering-related adverse consequences. RESULTS: A total of 49% of the study participants had falls, fractures, and injuries due to wandering behavior, and 43.7% demonstrated eloping behaviors. Persistent walking (OR = 2.6) and poor gait (OR = 0.9) were significant predictors of negative outcomes of wandering, while persistent walking (OR = 13.2) and passivity (OR = 2.55) predicted eloping behavior. However, there were no correlations between wandering-related adverse consequences and participants' characteristics (age, gender, race, ethnicity, and education), health status (Charlson comorbidity index), or neurocognitive abilities. CONCLUSION: Our results highlight the importance of identifying at-risk individuals so that effective interventions can be developed to reduce or prevent the adverse consequences of wandering.

Risk of treatment-related esophageal cancer among breast cancer survivors.

BACKGROUND: Radiotherapy for breast cancer may expose the esophagus to ionizing radiation, but no study has evaluated esophageal cancer risk after breast cancer associated with radiation dose or systemic therapy use. DESIGN: Nested case-control study of esophageal cancer among 289 748 ≥5-year survivors of female breast cancer from five population-based cancer registries (252 cases, 488 individually matched controls), with individualized radiation dosimetry and information abstracted from medical records. RESULTS: The largest contributors to esophageal radiation exposure were supraclavicular and internal mammary chain treatments. Esophageal cancer risk increased with increasing radiation dose to the esophageal tumor location (P(trend )< 0.001), with doses of ≥35 Gy associated with an odds ratio (OR) of 8.3 [95% confidence interval (CI) 2.7-28]. Patients with hormonal therapy ≤5 years preceding esophageal cancer diagnosis had lower risk (OR = 0.4, 95% CI 0.2-0.8). Based on few cases, alkylating agent chemotherapy did not appear to affect risk. Our data were consistent with a multiplicative effect of radiation and other esophageal cancer risk factors (e.g. smoking). CONCLUSIONS: Esophageal cancer is a radiation dose-related complication of radiotherapy for breast cancer, but absolute risk is low. At higher esophageal doses, the risk warrants consideration in radiotherapy risk assessment and long-term follow-up.

Central effects of estradiol in the regulation of food intake, body weight, and adiposity.

In recent years, obesity and its associated health disorders and costs have increased. Accumulation of adipose tissue, or fat, in the intra-abdominal adipose depot is associated with an increased risk of developing cardiovascular problems, type-2 diabetes mellitus, certain cancers, and other disorders like the metabolic syndrome. Males and females differ in terms of how and where their body fat is stored, in their hormonal secretions, and in their neural responses to signals regulating weight and body fat distribution. Men and post-menopausal women accumulate more fat in their intra-abdominal depots than pre-menopausal women, resulting in a greater risk of developing complications associated with obesity. The goal of this review is to discuss the current literature on sexual dimorphisms in body weight regulation, adipose tissue accrual and deposition.

Lemierre's--the sinister sore throat.

Lemierre's syndrome is a rare and sometimes life threatening condition that requires prompt management. A case is reported of a previously healthy young male with Lemierre's syndrome. He developed internal jugular vein and cavernous sinus thrombosis, metastatic abscesses in the temporal lobe and lungs, temporal lobe venous infarction and severe thrombocytopaenia. Discussed are aspects of clinical presentation, diagnosis and management issues.

E-cadherin in the assessment of aberrant placental cytotrophoblast turnover in pregnancies complicated by pre-eclampsia.

E-cadherin is a cell-cell adhesion protein expressed in cytotrophoblasts, which is lost as they differentiate and syncytialise. We have exploited E-cadherin as a marker of cytotrophoblasts to investigate villous tissue composition in first and third trimester placentae, both in normal pregnancy and pregnancies complicated by pre-eclampsia. We have achieved this by measuring expression levels of E-cadherin at the mRNA level, using Q-PCR, and at the protein level using semi-quantitative Western blotting. We have also combined E-cadherin immunohistochemistry with morphometric analysis of area measurements to define cytotrophoblast and syncytiotrophoblast compartments. This novel use of E-cadherin has revealed a decrease in the proportion of cytotrophoblasts in villous tissue as pregnancy progresses, in the absence of changes in syncytiotrophoblast cover. Moreover, in pre-eclampsia, placental E-cadherin was raised compared to syncytiotrophoblast, suggesting either exaggerated cytotrophoblast proliferation or impaired cytotrophoblast differentiation, both alterations of potential pathogenic importance.

B16F10 melanoma cell colonization of mouse lung is enhanced by partial pneumonectomy.

Surgical resection of lung tissue is employed clinically as a therapy for pulmonary metastases; however, local cancer recurrence is a frequent post-surgical complication. In a variety of small mammals, left pneumonectomy (PNX) initiates rapid compensatory hyperplasia of the remnant lung lobes restoring normal tissue mass, structure and function. Post-PNX compensatory lung growth is known to promote lung tumor formation in carcinogen-treated mice. The present study tests the hypothesis that PNX enhances experimental metastasis to lung. C57B1/6 mice subjected to PNX were given an intravenous injection of B16F10 melanoma cells at various stages of compensatory lung growth. Animals injected with B16F10 cells during the linear phase of the response had 77% to 260% more pulmonary metastases than mice subjected to thoracotomy (P < 0.01). Moreover, measurements of tumor area (mm2) revealed that PNX mice harbored a substantially larger lung tumor burden than control animals. Normalization of the tumor cell inoculum to lung mass yielded similar results. PNX had no effect on growth of sub-cutaneous B16F10 melanoma tumors, suggesting that experimental melanoma metastasis was enhanced by local alterations in the lung microenvironment. These results suggest (1) that PNX is a relevant model in which to investigate mechanisms of local cancer recurrence and, (2) melanoma cell metastatic potential is influenced, at least in part, by local factors modified during post-PNX compensatory lung growth.

A single amino acid is critical for the expression of B-cell epitopes on the helicase domain of the pestivirus NS3 protein.

Truncated NS3 proteins, expressed by recombinant baculoviruses, were used to investigate the location of conserved B-cell epitopes on this non-structural bovine viral diarrhoea virus (BVDV) protein. A goat anti-pestivirus antiserum, and a panel of anti-NS3 monoclonal antibodies, including the BVDV-1 specific antibody P1D8, were used to verify the presence or absence of the epitopes. Interestingly, the monoclonal antibodies reacted only with the truncated protein encompassing the helicase domain of NS3. Expression of the B-cell epitopes was dependent on, but not within, a 57 amino acid sequence at the carboxy-terminal end of this protein, supporting observations that these conserved epitopes are conformational in nature. A comparison of deduced amino acid sequences of the helicase domain from BVDV-1, BVDV-2, BDV and CSFV isolates highlighted a single amino acid that appeared to be unique to P1D8-reactive BVDV-1 isolates. Site-directed mutagenesis studies confirmed that this amino acid is critical for the expression of the BVDV-1 specific NS3 epitope recognised by the P1D8 monoclonal antibody. Surprisingly, the amino acid was also important for an epitope recognised by two group-specific monoclonal antibodies, P1H11 and P4A11. Protein modelling studies, based on the structure of the hepatitis C NS3 helicase domain, indicated that this amino acid occupies a prominent position on the surface of the protein.

Implications of post-pneumonectomy compensatory lung growth in pulmonary physiology and disease.

In a number of species, partial pneumonectomy initiates hormonally regulated compensatory growth of the remaining lung lobes that restores normal mass, structure and function. Compensation is qualitatively similar across species, but differs with gender, age and hormonal status. Although the biology of response is best characterized in rats, dogs have proven valuable in defining post-operative physiological adaptations. Most recently, mice were recognized to offer unique opportunities to explore the genetic basis of the response, as well as to evaluate associated detrimental effects of pathophysiological significance in animals exposed to carcinogens. The pneumonectomy model thus offers powerful insight concerning adaptive organ growth.

Helicobacter pylori infection in rural China: exposure to domestic animals during childhood and adulthood.

Little is known about the mode of transmission of Helicobacter pylori, one of the most common human bacterial infections. Some domestic animals, including the cat, have been suggested as a reservoir of H. pylori disease, but the data have been inconsistent. This paper evaluates the role of exposure to pets and other domestic animals in the etiology of H. pylori in a rural area of China with a high prevalence of H. pylori infection. In this double-blind, population-based, cross-sectional investigation, interviews were completed with 3,288 (1994 seropositive, 1,019 seronegative, 275 indeterminate) H. pylori-infected adults enrolled in a randomized intervention trial in Linqu County, Shandong Province, China. We found no evidence to suggest that exposure to pets or other domestic animals during either childhood or adulthood was related to the prevalence of H. pylori infection. In fact, odds ratios (ORs) were reduced for subjects who had kept a cat (OR = 0.7, 95% CI = 0.4-1.0) or any animal (OR = 0.5, 95% CI = 0.3-0.9) in the house as an adult, or a cat as a child (OR = 0.7, 95% CI =0.5-1.0). ORs were also reduced for all 11 types of animal studied that subjects had kept in their courtyard as an adult. These findings suggest that zoonotic transmission, including that from domestic cats, is an unlikely route of H. pylori infection in this rural Chinese population.

Family cancer history and susceptibility to oral carcinoma in Puerto Rico.

BACKGROUND: Use of alcohol and tobacco are the major risk factors for cancers of the oral cavity and pharynx in most of the world. A heritable component to oral carcinoma risk also has been suggested, although only limited data are available on familial aggregation of this disease. METHODS: A population-based case-control study of 342 subjects with carcinomas of the oral cavity and pharynx (oral carcinoma) and 521 controls was conducted in Puerto Rico. The relation between family history of carcinomas of the oral cavity, the upper aerodigestive tract (UADT), and other selected sites with risk of oral carcinoma was explored using logistic regression modeling techniques. RESULTS: Risk of oral carcinoma was elevated for subjects reporting a first-degree relative with carcinoma of the oral cavity (odds ratio [OR], 2.5; 95% confidence interval [CI], 0.8-8.0) or any UADT carcinoma (OR, 2.6; 95% CI, 1.4-4.8). The increased risk associated with family history of UADT carcinoma tended to be greatest for subjects with known risk factors (i.e., heavy consumption of alcohol and/or tobacco and infrequent intake of raw fruits and vegetables) and with oral carcinoma diagnoses at ages younger than 65 years. CONCLUSIONS: These findings are consistent with a heritable component to oral carcinoma, although shared lifestyle risk factors may be partially involved.

Diagnostic radiation and the risk of multiple myeloma (United States).

OBJECTIVE: To evaluate the relationship between cumulative lifetime exposure to diagnostic radiation and the risk of multiple myeloma using data from a large, multi-center, population-based case-control study. METHODS: Study subjects included a total of 540 cases with newly diagnosed multiple myeloma and 1998 frequency-matched population controls living in three areas of the United States (Georgia, Michigan, New Jersey). Information on exposure to diagnostic X-rays was obtained by personal interview. RESULTS: No association was found between case-control status and the total number of reported diagnostic X-rays of any type (odds ratio (OR) for 20 or more compared to less than 5 X-rays = 0.9, 95% confidence interval (95% CI) = 0.7-1.2). There was no evidence of an excess risk of multiple myeloma among individuals who reported exposure to 10 or more diagnostic X-rays that impart a relatively high radiation dose to the bone marrow, as compared to individuals reporting no such exposures (OR 0.7, 95% CI 0.4-1.3). CONCLUSIONS: These data suggest that exposure to diagnostic X-rays has a negligible impact, if any, on risk of developing multiple myeloma.

Mouthwash in the etiology of oral cancer in Puerto Rico.

OBJECTIVES: To determine if the risk of cancers of the mouth and pharynx is associated with mouthwash use in Puerto Rico, an area of relatively high risk. METHODS: Interviews were conducted with 342 cases of oral and pharyngeal cancer registered in Puerto Rico and diagnosed between 1992 and 1995 and with 521 population-based controls regarding mouthwash use and other factors. Mouthwash-related risks were estimated using unconditional logistic regression controlling for potential confounders. RESULTS: The adjusted odds ratio associated with using mouthwash with an alcohol content of 25% or greater was 1.0. Risks were not higher with greater frequency, years of use, or lifetime mouthwash exposure. Among tobacco and alcohol abstainers the odds ratio associated with mouthwash use was 2.8 (CI = 0.8-9.9), in contrast to 0.8 (CI = 0.4-1.7) and 0.9 (CI = 0.6-1.3) among those with light and heavy cigarette smoking/alcohol drinking behaviors, respectively. CONCLUSIONS: There was no overall increased risk of oral cancer associated with mouthwash use. An elevated, but not statistically significant, risk was observed among the small number of subjects who neither smoked cigarettes nor drank alcohol, among whom an effect of alcohol-containing mouthwash would be most likely evident. Our findings indicate the need to clarify the mechanisms of oral carcinogenesis, including the possible role of alcohol-containing mouthwash.

An intervention trial to inhibit the progression of precancerous gastric lesions: compliance, serum micronutrients and S-allyl cysteine levels, and toxicity.

Gastric cancer is the second most frequent cause of death from cancer in the world and the leading cause of death from cancer in China. In September 1995, we launched a randomized multi-intervention trial to inhibit the progression of precancerous gastric lesions in Linqu County, Shandong Province, an area of China with one of the world's highest rates of gastric cancer. Treatment compliance was measured by pill counts and quarterly serum concentrations of vitamin C, vitamin E and S-allyl cysteine. In 1999, toxicity information was collected from each trial participant to evaluate treatment-related side-effects during the trial. Compliance rates were 93% and 92.9% for 39 months of treatment with the vitamins/mineral and garlic preparation, respectively. The means for serum concentrations of vitamins C and E were 7.2 microg/ml and 1695 microg/dl among subjects in the active treatment groups compared with 3.1 microg/ml and 752 microg/dl among subjects in the placebo treatment group, respectively. No significant differences in side-effects were observed between the placebo treatment group and the vitamins/mineral and garlic preparation treatment groups during the 39-month trial period.

Structure of the adenovirus E4 Orf6 protein predicted by fold recognition and comparative protein modeling.

To facilitate investigation of the molecular and biochemical functions of the adenovirus E4 Orf6 protein, we sought to derive three-dimensional structural information using computational methods, particularly threading and comparative protein modeling. The amino acid sequence of the protein was used for secondary structure and hidden Markov model (HMM) analyses, and for fold recognition by the ProCeryon program. Six alternative models were generated from the top-scoring folds identified by threading. These models were examined by 3D-1D analysis and evaluated in the light of available experimental evidence. The final model of the E4 protein derived from these and additional threading calculations was a chimera, with the tertiary structure of its C-terminal 226 residues derived from a TIM barrel template and a mainly alpha-nonbundle topology for its poorly conserved N-terminal 68 residues. To assess the accuracy of this model, additional threading calculations were performed with E4 Orf6 sequences altered as in previous experimental studies. The proposed structural model is consistent with the reported secondary structure of a functionally important C-terminal sequence and can account for the properties of proteins carrying alterations in functionally important sequences or of those that disrupt an unusual zinc-coordination motif.