After hMSH2 and hMLH1- what next? Analysis of three-generational, population-based, early-onset colorectal cancer families

The aim of our study was to examine the role of genetic factors on early-onset colorectal cancer after excluding the impact of germline mutations in the two major mismatch repair genes. A total of 131 incident probands, under 45 years at diagnosis of a first primary colorectal cancer selected from the Victorian Cancer Registry, and their first-and second-degree relatives, were interviewed. Germline DNA from all 12 probands with a family history meeting the modified Amsterdam Criteria for Hereditary Non-Polyposis Colorectal Cancer (HNPCC) and a random sample of 31 of the remaining probands was screened for mutations in hMSH2 and hMLH1 via manual sequencing. Germline mutations were identified in 6 of the 131 probands (5%), all from the "HNPCC" families. Of the remaining 125 probands, 51 (41%) reported at least one first-or second-degree relative with colorectal cancer with an excess of colorectal cancer in first-degree relatives (SMR = 2.7, 95% CI = 1.7-4.1, p < 0.001). The lifetime risk to age 70 for first-degree relatives was 8.0% (5.0-12.8%), compared to the Victorian population risk of 3.2% (p = 0.01). The best fitting major gene model was a recessively-inherited risk of 98% to age 70 (95% CI = 24-100%) carried by 0.17% of the population and would explain 15% of all colorectal cancer in cases with a diagnosis before age 45. Early-onset colorectal cancer is strongly familial even after excluding families found to be segregating a mutation in either of the 2 major mismatch repair genes. There is evidence for a role of yet to be identified genes associated with a high recessively-inherited risk of colorectal cancer.

Intervening early to reduce developmentally harmful substance use among youth populations

Early-onset or frequent substance use during adolescence increases the risk of developing mental health problems, as well as a range of other adverse outcomes (eg, alcohol or drug dependence, educational underachievement, health problems, social difficulties) during late adolescence and early adulthood.

Increases in rates of risky drinking among young people are particularly concerning, suggesting that an effective, evidence-based alcohol policy and preventive framework needs to be developed.

Restricting the supply of licit and illicit substances to adolescents, delaying the age that licit substances can be legally purchased, reducing positive media portrayals of substance use, and banning targeted promotions, should be universal, public prevention priorities.

Mass-media campaigns need to deliver coherent and credible evidence-based messages to young people, utilising a broad array of dissemination strategies.

Clear policy and guidelines for parents regarding appropriate alcohol use for adolescents also need to be developed.

Prevention programs should target children and adolescents in families with parents who use drugs, young people who have been suspended from school, or those with mental health problems.

Preventive screening and targeted brief interventions can be effectively delivered in a variety of settings by a range of health professionals.

Predicting early intitiation of alcohol use: a prospective study of Australian Children

This study explores the social, contextual and individual factors that predict early initiation of alcohol use. A state-wide representative sample of 927 fifth-grade students, in Victoria, Australia were surveyed. Students were resurveyed in the sixth and seventh grade. Risk and protective factors were measured with a modified version of the Communities That Care youth survey. Alcohol use was measured to assess transition from alcohol nonuse to use. Social contexts perceived to provide easier access to alcohol and drugs were found to be the clearest predictors of early onset alcohol use. The limitations and implications of these findings are discussed.

Morphologic and functional characterization of granulocytes and macrophages in embryonic and adult zebrafish.

The zebrafish is a useful model organism for developmental and genetic studies. The morphology and function of zebrafish myeloid cells were characterized. Adult zebrafish contain 2 distinct granulocytes, a heterophil and a rarer eosinophil, both of which circulate and are generated in the kidney, the adult hematopoietic organ. Heterophils show strong histochemical myeloperoxidasic activity, although weaker peroxidase activity was observed under some conditions in eosinophils and erythrocytes. Embryonic zebrafish have circulating immature heterophils by 48 hours after fertilization (hpf). A zebrafish myeloperoxidase homologue (myeloid-specific peroxidase; mpx) was isolated. Phylogenetic analysis suggested it represented a gene ancestral to the mammalian myeloperoxidase gene family. It was expressed in adult granulocytes and in embryos from 18 hpf, first diffusely in the axial intermediate cell mass and then discretely in a dispersed cell population. Comparison of hemoglobinized cell distribution, mpx gene expression, and myeloperoxidase histochemistry in wild-type and mutant embryos confirmed that the latter reliably identified a population of myeloid cells. Studies in embryos after tail transection demonstrated that mpx- and peroxidase-expressing cells were mobile and localized to a site of inflammation, indicating functional capability of these embryonic granulocytes. Embryonic macrophages removed carbon particles from the circulation by phagocytosis. Collectively, these observations have demonstrated the early onset of zebrafish granulopoiesis, have proved that granulocytes circulate by 48 hpf, and have demonstrated the functional activity of embryonic granulocytes and macrophages. These observations will facilitate the application of this genetically tractable organism to the study of myelopoiesis.

VNTR polymorphism of the insulin gene and childhood overweight in a general population

Objective: The VNTR polymorphism 5' of the insulin gene has been related to obesity in a previous study on children with early onset of severe obesity. Our purpose was to analyze the association between this polymorphism and adiposity variability in an unselected population of children and adolescents in northern France.

Research Methods and Procedures: In 293 nuclear families from the Fleurbaix Laventie Ville Santé study, we genotyped the INS VNTR polymorphism in 431 children and adolescents (8 to 18 years of age) and their parents. Overweight was defined according to the international definition in both children and adults. A transmission disequilibrium test in families with an overweight offspring was performed. The prevalence of overweight was compared according to genotype. The effect of the genotype on BMI and waist circumference was tested with a linear regression model, adjusting for age, gender, and Tanner stage.

Results: There was an undertransmission of class III alleles from heterozygous parents to their overweight offspring (p < 0.002). Overweight was associated with class I alleles in children and adolescents (12% I/I, I/III vs. 3% III/III; p < 0.08). Those with a class III/III genotype had a 1 kg/m2 lower mean BMI (p = 0.04) and 3 cm lower waist circumference (p = 0.02) than those bearing one or two class I alleles. No association of adiposity or obesity with class I alleles was found in parents.

Discussion: INS VNTR polymorphism seems to contribute to differences in adiposity level in the general population of children and adolescents.

Novel agents that potentially inhibit irinotecan-induced diarrhea

Irinotecan (CPT-11, 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin) has exhibited clinical activities against a broad spectrum of carcinomas by inhibiting DNA topoisomerase I (Topo I). However, severe and unpredictable dosing-limiting toxicities (mainly myelosuppression and severe diarrhea) hinder its clinical use. The latter consists of early and late-onset diarrhea, occurring within 24 hr or ≥ 24 hr after CPT-11 administration, respectively. This review highlights novel agents potentially inhibiting CPT-11-induced diarrhea, which are designed and tested under guidance of disposition pathways and potential toxicity mechanisms. Early-onset diarrhea is observed immediately after CPT-11 infusion and probably due to the inhibition of acetylcholinesterase activity, which can be eliminated by administration of atropine. Lateonset diarrhea appears to be associated with intestinal exposure to SN-38 (7-ethyl-10-hydroxycamptothecin), the major active metabolite of CPT-11, which may bind to Topo I and induce apoptosis of intestinal epithelia, leading to the disturbance in the absorptive and secretory functions of mucosa. CPT-11 and SN-38 may also stimulate the production of pro-inflammatory cytokines and prostaglandins (PGs), thus inducing the secretion of Na⁺ and Cl^-. Early treatment of severe late-onset diarrhea with oral high-dose loperamide has decreased patient morbidity. Extensive studies have been conducted to identify other potential agents to ameliorate diarrhea in preclinical and clinical models. These include intestinal alkalizing agents, oral antibiotics, enzyme inducers, P-glycoprotein (PgP) inhibitors, cyclooxygenase-2 (COX-2) inhibitors, tumor necrosis factor-agr (TNF-α) inhibitors, or blockers of biliary excretion of SN-38. Further studies are needed to identify the molecular targets associated with CPT-11 toxicity and safe and effective agents for alleviating CPT-11-induced diarrhea.

EBSD analysis of a Ti-IF steel subjected to hot torsion in the ferritic region

The effect of grain size on the warm deformation behaviour of a titanium stabilized interstitial free steel was investigated using hot torsion. Tests were performed at temperatures between 765 °C and 850 °C at strain rates between 0.003 s−1 and 1 s−1 for samples with grain sizes of 25 μm, 75 μm and 150 μm. The structures were observed using EBSD analysis and are consistent with those expected for materials dominated by dynamic recovery. Some evidence was found for small amounts of thermally induced migration of pre-existing boundary (bulging) and for the generation of new segments of high angle boundaries by continuous dynamic recrystallization. The early onset of a steady-state flow stress in the finer grained samples is attributed to one or a combination of thermally induced boundary migration and enhanced rates of recovery near subgrain (and grain) boundaries.

To do or not to do (exercise) : physical activity in the lives of people with cerebral palsy

We examined the lives of adults with cerebral palsy who had minimal involvement in physical activity (Judy, aged 60; Alana, aged 29), who were involved in physical activity (Amy, aged 25; Ben, aged, 30), or who had minimal involvement in physical activity and who then participated in physical activity (David, aged 27; Tim, aged, 24). After receiving ethical approval, a life-history research approach (Denzin, 1989: Interpretive biography. Newbury Park, CA: Sage) was used, with the participants’ stories being interpreted using primarily psychodynamic theory (Freud, Erikson, Adler, Basch) to gain insight into their meaning and experiences of physical activity.

Judy and Alana had similar childhood experiences, which included: performing difficult, and sometimes painful, physiotherapy; wearing callipers to assist their walking; lacking competence at physical activity; and being socially isolated from their classmates. These aspects of their life histories seemed to contribute to their subsequent avoidance of physical activity and early onset of functional decline.

Amy and Ben had negative experiences with physical activity as children (similar to Judy and Alana), but were involved in, and valued, physical activity as adults. Physical activity was a means of displaying competence, delaying further functional loss, and becoming socially connected.

David and Tim lost the ability to walk in early adolescence. The minimal physical activity in which they engaged during their adult lives was directed towards trying to walk again. Walking seemed to be intimately connected with psychosocial growth. David’s weight-training programme seemed to provide him with another avenue for self-improvement towards his goal of attracting a life partner. Tim’s warm-water aerobic programme provided him with an opportunity to develop competence at swimming and at walking, and to enhance his self-esteem for these activities.

Involvement in physical activity may be important for people with cerebral palsy in their endeavours to successfully face the various psychosocial challenges throughout life. Implications of this research include: parents and teachers of children with cerebral palsy should provide support for their involvement in physical activity; physiotherapists should try to reduce the pain and increase the perceived relevancy of the treatments they deliver to young people with cerebral palsy; and psychologists should be aware of some of the difficulties people with cerebral palsy face and how they may manifest in adults with the condition.

Ontogeny of putative GABAergic neurons and their receptors in the nervous system of the crayfish Cherax destructor

Inhibitory neurons exert control the expression of many aspects of behaviour by regulating the effectiveness of excitatory neural function. By comparison with excitatory neural systems, relatively little is known about the development of inhibitory neurons and the influence which these neurons exert on the development of other neural systems. Two issues which relate to the development of inhibitory neurons are of particular interest. First, a paradox arises when inhibitory neurons are considered in terms of modern models of synaptic development which involve activity-dependent mechanisms of synaptic plasticity. Second, there is some evidence that inhibitory neurotransmitters may act in a special trophic manner during the early development of nervous systems. Investigations of these issues would be greatly facilitated in a neural system in which it was possible to experimentally control aspects of the development of individual pre- and postsynaptic cells. The aim of the results presented in this thesis was to characterise the normal development of one such system: the GABAergic inhibitory system of the Australian freshwater crayfish, Cherax destructor. The ontogeny of the inhibitory neurotransmitter GABA across the embryonic period of 30% to 100% development was investigated using immunohistochemical techniques. GABA-like immunoreactive cells and fibres were first detected in the embryonic brain region. The expression of GABA-like immunoreactivity progressed along a rostro-caudal gradient, with GABA-like immunoreactive cells being detected in the most anterior thoracic ganglia at 45% development and in all ganglia by 65% development. GABA-like immunoreactive fibres were evident in peripheral nerves as early as 55% development and ramified extensively throughout the neuropil of the nervous system by 65% development. By contrast, immunoreactivity to the primary excitatory neurotransmitter, glutamate, was not detected until 60-65% development. Glutamate-like immunoreactivity at 60-65% development was evident only in the form of punctate staining in the midline of the ventral nerve cord. Cell body staining was observed only at 90% development and was restricted to only a few cells on the periphery of the ventral nerve cord. Radio-labelled ligand binding methods and autoradiography were used to study the expression of putative GABA receptors in the Cherax embryos from 30% to 100% development. Specific binding was evident in the earliest embryos studies at 30% development. There was an initial increase in binding from 30% to 40% development, followed by a dramatic drop to almost zero binding at 50-55% development. This was followed by a gradual increase in binding levels with age, reaching a plateau at 85% development. Preliminary pharmacological evaluation of binding indicated that at least three GABA receptor types were expressed during embryonic development. Methods for culturing, dissociated neural tissues explanted form Cherax embryos at 85% development were established. The success of cultures was demonstrated by neurite extension, and neuronal networks in which neurons appeared to form connections with other neurons and with explanted muscle cells after two days in culture. Immunohistochemical studies demonstrated that some explanted neurons expressed GABA-like immunoreactivity within two days of explanting. These studies have provided a comprehensive description of the development of GABAergic neurons and their receptors in Cherax destructor embryos. The very early expression of GABA-like immunoreactivity, coupled with the early onset of specific GABA binding, strongly indicates that the GABAergic neurons are functional and able to exert an effect on other cells during much of the period of nervous system development in crayfish embryos. These results support the hypothesis that inhibitory neurons may play an important role as regulators of the overall process of assembly and maturation of the nervous system and provide a substantial basis for future experimental studies in which the specific action of inhibitory neurons on the development of discrete components of the crayfish nervous system may be investigated.

The impact of school suspension on student tobacco use : a longitudinal study in Victoria, Australia, and Washington State, United States

Context: School suspension may have unintended consequences in contributing to problem behaviors, including dropping out from school, substance use, and antisocial behavior. Tobacco use is an early-onset problem behavior, but prospective studies of the effects of suspension on tobacco use are lacking.

Method: Longitudinal school-based survey of students drawn as a two-stage cluster sample, administered in 2002 and 2003, in Washington State, United States, and Victoria, Australia. The study uses statewide representative samples of students in Grades 7 and 9 (N = 3,599). Results: Rates of tobacco use were higher for Victorian than Washington State students. School suspension remained a predictor of current tobacco use at 12-month follow-up, after controlling for established risk factors including prior tobacco and other drug use for Grade 7 but not Grade 9 students.

Conclusions: School suspension is associated with early adolescent tobacco use, itself an established predictor of adverse outcomes in young people. Findings suggest the need to explore process mechanisms and alternatives to school suspensions as a response to challenging student behavior in early adolescence.

Altered intracellular localization and valosin-containing protein (p97 VCP) interaction underlie ATP7A-related distal motor neuropathy

ATP7A is a P-type ATPase that regulates cellular copper homeostasis by activity at the trans-Golgi network (TGN) and plasma membrane (PM), with the location normally governed by intracellular copper concentration. Defects in ATP7A lead to Menkes disease or its milder variant, occipital horn syndrome or to a newly discovered condition, ATP7A-related distal motor neuropathy (DMN), for which the precise pathophysiology has been obscure. We investigated two ATP7A motor neuropathy mutations (T994I, P1386S) previously associated with abnormal intracellular trafficking. In the patients' fibroblasts, total internal reflection fluorescence microscopy indicated a shift in steady-state equilibrium of ATP7AT994I and ATP7AP1386S, with exaggerated PM localization. Transfection of Hek293T cells and NSC-34 motor neurons with the mutant alleles tagged with the Venus fluorescent protein also revealed excess PM localization. Endocytic retrieval of the mutant alleles from the PM to the TGN was impaired. Immunoprecipitation assays revealed an abnormal interaction between ATP7AT994I and p97/VCP, an ubiquitin-selective chaperone which is mutated in two autosomal dominant forms of motor neuron disease: amyotrophic lateral sclerosis and inclusion body myopathy with early-onset Paget disease and fronto-temporal dementia. Small-interfering RNA (SiRNA) knockdown of p97/VCP corrected ATP7AT994I mislocalization. Flow cytometry documented that non-permeabilized ATP7AP1386S fibroblasts bound a carboxyl-terminal ATP7A antibody, consistent with relocation of the ATP7A di-leucine endocytic retrieval signal to the extracellular surface and partially destabilized insertion of the eighth transmembrane helix. Our findings illuminate the mechanisms underlying ATP7A-related DMN and establish a link between p97/VCP and genetically distinct forms of motor neuron degeneration.

Underlying neurobiology and clinical correlates of mania status after subthalamic nucleus deep brain stimulation in Parkinson's Disease : a review of the literature

Deep brain stimulation (DBS) is a novel and effective surgical intervention for refractory Parkinson's disease (PD). The authors review the current literature to identify the clinical correlates associated with subthalamic nucleus (STN) DBS-induced hypomania/mania in PD patients. Ventromedial electrode placement has been most consistently implicated in the induction of STN DBS-induced mania. There is some evidence of symptom amelioration when electrode placement is switched to a more dorsolateral contact. Additional clinical correlates may include unipolar stimulation, higher voltage (>3 V), male sex, and/or early-onset PD. STN DBS-induced psychiatric adverse events emphasize the need for comprehensive psychiatric presurgical evaluation and follow-up in PD patients. Animal studies and prospective clinical research, combined with advanced neuroimaging techniques, are needed to identify clinical correlates and underlying neurobiological mechanisms of STN DBS-induced mania. Such working models would serve to further our understanding of the neurobiological underpinnings of mania and contribute valuable new insight toward development of future DBS mood-stabilization therapies.