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Abstract Despite a comprehensive mapping of the Parkinson's disease (PD)-related mRNA and protein leucine-rich repeat kinase 2 (LRRK2) in the mammalian brain, its physiological function in healthy individuals remains enigmatic. Based on its structural features and kinase properties, LRRK2 may interact with other proteins involved in signalling pathways. Here, we show a widespread LRRK2 mRNA and/or protein expression in expanded or differentiated human mesencephalic neural progenitor cells (hmNPCs) and in post-mortem substantia nigra PD patients. Using small interfering RNA duplexes targeting LRRK2 in hmNPCs following their differentiation into glia and neurons, we observed a reduced number of dopaminergic neurons due to apoptosis in LRRK2 knockdown samples. LRRK2-deficient hmNPCs exhibited elevated cell cycle- and cell death-related markers. In conclusion, a reduction of LRRK2 expression in hmNPCs severely impaired dopaminergic differentiation and/or survival of dopaminergic neurons most likely via preserving or reactivating the cell cycle.

Reversible formation of PHF-like phosphorylated tau, an early feature of Alzheimer's disease (AD) was previously shown to occur in torpor during hibernation in the Golden hamster (Syrian hamster, Mesocricetus auratus ). Here, we tackled the question to what extent hibernating Golden hamsters can serve as a model for the early stage of AD. During early AD, anosmia, the loss of olfactory function, is a common and typical feature. We, thus, investigated tau phosphorylation, synaptic plasticity and behavioral physiology of the olfactory system during hibernation. Tau was phosphorylated on several AD-relevant epitopes, and distribution of PHF-like phosphorylated tau in the olfactory bulb was quite similar to what is seen in AD. Tau phosphorylation was not associated with a destabilization of microtubules and did not lead to fibril formation. Previously, we observed a transient spine reduction in pyramidal cells in the hippocampus, which is correlated with the distribution of phosphorylated tau. Here we show that granule cells in the olfactory bulb are devoid of phosphorylated tau and maintain their spines number during torpor. No reduction of synaptic proteins was observed. However, hibernation did impair the recall performance in a two-odor discrimination task. We conclude that hibernation is associated with a specific olfactory memory deficit, which might not be attributed to the formation of PHF-like phosphorylated tau within the olfactory bulb. We discuss a possible involvement of modulatory input provided by cholinergic neurons in the basal forebrain, which are affected by hibernation.

Background: Several studies have attributed racial disparities in cancer incidence and mortality to variances in socioeconomic status and health insurance coverage. However, an Institute of Medicine report found that blacks received lower quality care than whites after controlling for health insurance, income, and disease severity., Methods: To examine the effects of race on colorectal cancer outcomes within a single setting, the authors performed a retrospective cohort study that analyzed the cancer registry, billing, and medical records of 365 university hospital patients (175 blacks and 190 whites) diagnosed with stage II-IV colon cancer between 2000 and 2005. Racial differences in the quality (effectiveness and timeliness) of stage-specific colon cancer treatment (colectomy and chemotherapy) were examined after adjusting for socioeconomic status, health insurance coverage, sex, age, and marital status., Results: Blacks and whites had similar sociodemographic characteristics, tumor stage and site, quality of care, and health outcomes. Age and diagnostic stage were predictors of quality of care and mortality. Although few patients (5.8%) were uninsured, they were more likely to present at advanced stages (61.9% at stage IV) and die (76.2%) than privately insured and publicly insured patients (p = .002)., Conclusions: In a population without racial differences in socioeconomic status or insurance coverage, patients receive the same quality of care, regardless of racial distinction, and have similar health outcomes. Age, diagnostic stage, and health insurance coverage remained independently associated with mortality. Future studies of disparities in colon cancer treatment should examine sociocultural barriers to accessing appropriate care in various healthcare settings., (Copyright 2009 American Cancer Society.)

Objective: Malignant hyperthermia (MH) is a classically unapparent pharmacogenetic disorder of the skeletal muscles triggered by inhalational anesthetics or depolarizing muscle relaxants. The disposition to MH is inherited in an autosomal-dominant manner and is primarily due to mutations in the gene for the ryanodine receptor type 1 (RyR1). The present study intended to analyze whether mild muscular symptoms (elevation of the resting CK, cramps in the calves, slight calf hypertrophy) may be associated with susceptibility to MH and/or with histopathological changes., Methods: A muscle biopsy was taken from 12 out of 44 blood relatives (three generations) of a large family and was investigated with the halothane/caffeine in vitro contracture test (IVCT). Afterwards a histological, histochemical and immunhistological examination was performed. Altogether in 29 persons the DNA was analyzed for mutations in the RyR1-gene., Results: Eight persons were diagnosed as susceptible to MH (MHS) by the IVCT, 4 were MH negative. All MHS persons carried the MH causative c.6617C > T (Thr2206Met) mutation and showed slight clinical signs of a myopathy as well as mild biopsy changes with isolated hypotrophic fibers and disseminated small areas with reduction of oxidative staining (multi-minicore like lesions). The Thr2206Met mutation was identified in another further 9 relatives who also experienced mild myopathological features. Clinical MH incidents were not reported in this large family., Conclusion: The RyR1 Thr2206Met mutation is one of the most frequent mutations in the European MH population but carriers are normally healthy. In this study we could demonstrate that the MH causative Thr2206Met mutation may also be associated both with clinical symptoms of a mild myopathy and histopathological changes in the oxidative inter myofibrillar network.

Despite a comprehensive mapping of the Parkinson's disease (PD)-related mRNA and protein leucine-rich repeat kinase 2 (LRRK2) in the mammalian brain, its physiological function in healthy individuals remains enigmatic. Based on its structural features and kinase properties, LRRK2 may interact with other proteins involved in signalling pathways. Here, we show a widespread LRRK2 mRNA and/or protein expression in expanded or differentiated human mesencephalic neural progenitor cells (hmNPCs) and in post-mortem substantia nigra PD patients. Using small interfering RNA duplexes targeting LRRK2 in hmNPCs following their differentiation into glia and neurons, we observed a reduced number of dopaminergic neurons due to apoptosis in LRRK2 knockdown samples. LRRK2-deficient hmNPCs exhibited elevated cell cycle- and cell death-related markers. In conclusion, a reduction of LRRK2 expression in hmNPCs severely impaired dopaminergic differentiation and/or survival of dopaminergic neurons most likely via preserving or reactivating the cell cycle.

African Americans are disproportionately burdened with colorectal cancer. Although incidence and mortality rates have declined in the past two decades, the disparity in health outcomes has progressively increased. This comprehensive review examines the existing literature regarding racial disparities in colorectal cancer screening, stage at diagnosis, and treatment to determine if differences exist in the quality of care delivered to African Americans. A comprehensive review of relevant literature was performed. Two databases (EBSCOHOST Academic Search Premier and Scopus) were searched from 2000 to 2007. Articles that assessed racial disparities in colorectal cancer screening, stage of disease at diagnosis, and treatment were selected. The majority of studies identified examined colorectal cancer screening outcomes. Although racial disparities in screening have diminished in recent years, African American men and women continue to have higher colorectal cancer incidence and mortality rates and are diagnosed at more advanced stages. Several studies regarding stage of disease at diagnosis identified socioeconomic status (SES) and health insurance status as major determinants of disparity. However, some studies found significant racial disparities even after controlling for these factors. Racial disparities in treatment were also found at various diagnostic stages. Many factors affecting disparities between African Americans and Whites in colorectal cancer incidence and mortality remain unexplained. Although the importance of tumor biology, genetics, and lifestyle risk factors have been established, prime sociodemographic factors need further examination to understand variances in the care of African Americans diagnosed with colorectal cancer.

The reaction of lysine and arginine residues of proteins with 1,2-dicarbonyl compounds result in the formation of advanced glycation end products (AGEs). Accumulation of AGEs is a characteristic feature of the aging brain and contributes to the development of neurodegenerative diseases such as Alzheimer's disease (AD). Therefore, it is of particular interest to study the cellular defense mechanisms against AGE formation and particularly the detoxification of their precursors. AGE precursor compounds such as methylglyoxal and glyoxal were cellulary detoxified by the glyoxalase system, consisting of glyoxalases I and II. Glyoxalase I levels are diminished in old aged brains but elevated in AD brains. However, it is still unknown how glyoxalase I level of AD brains changes in a disease and in an age-dependent manner. Therefore, we investigated the AD stage- and the age-dependent levels of glyoxalase I in the Brodmann area 22 of AD brains (n=25) and healthy controls (n=10). Our results obtained from RT-PCR reveal reducing glyoxalase I RNA levels with advancing stage of AD and with increasing age. Western Blot analysis indicates that in comparison to healthy controls, glyoxalase I protein amounts are 1.5-fold increased in early AD subjects and continuously decrease in middle and late stages of AD. The glyoxalase I protein amounts of AD patients also decrease with age. Results obtained from glyoxalase I activity measurement show 1.05-1.2-fold diminished levels in AD brains compared to healthy controls and no significant decrease neither with the stage of AD nor with age. The immunohistochemical investigations demonstrate an elevated number of glyoxalase I stained neurons in brains of early and middle but not in late AD subjects compared to age-matched healthy controls. In addition, the stage-dependent immunohistochemical investigation demonstrates that with reduced glyoxalase I staining AGE deposits prevail, specifically in late stage of AD. In conclusion, the decrease of glyoxalase I expression with increasing AD stage might be one reason for methylglyoxal-induced neuronal impairment, apoptosis, and AGE formation in plaques and tangles.

Increased modification and crosslinking of proteins by advanced glycation end products (AGEs) is a characteristic feature of aging, and contributes to the formation of many of the lesions of neurodegenerative diseases including neurofibrillary tangles and amyloid plaques in Alzheimer's disease. Therefore, defense mechanisms against AGE formation or detoxification of their precursors such as the glyoxalase system are of particular interest in aging research. Thus, we investigated the age-dependent protein expression, the activity as well as the RNA level of glyoxalase I in Brodmann area 22 (auditory association area of superior temporal gyrus) of the human cerebral cortex. Our immunohistochemical results demonstrate the localization of glyoxalase I in neurons, predominantly pyramidal cells, as well as in astroglia, located predominantly in the subpial region. The number of glyoxalase I expressing neurons and astroglia increases with age, with a peak at approximately 55 years, and progressively decreases thereafter. These results were confirmed by biochemical investigations in total brain tissue, where the RNA, the protein level as well as the activity of glyoxalase I enzyme were analyzed in different age groups. In conclusion, the increase in glyoxalase I expression up to the age of 55 may be a compensatory mechanism against high oxoaldyde levels and the accumulation of AGEs. However, the decline of glyoxalase expression and activity in old age, possibly caused by impairment in transcription or/and translation, may subsequently lead to increased levels of reactive carbonyl compounds, followed by protein crosslinking, inflammation, oxidative stress and neuronal degeneration.

In this immunohistochemical study, the age- and stage-dependent accumulation of advanced glycation end-products (AGEs) in Alzheimer's disease (AD) and their relation to the formation of neurofibrillary tangles and neuronal cell death was investigated. For this purpose, the distribution of AGEs in neurons and glia was analyzed in the auditory association area of superior temporal gyrus (Brodmann area 22) of young and old non-demented controls and compared with early- and late-stage AD. A possible co-localization of AGEs with typical hallmarks of AD, such as hyperphosphorylated tau (as a marker for disturbed kinase/phosphatase activity), nNOS (as a marker for nitroxidative stress) and caspase-3 (as a marker of apoptotic cell death), was also investigated. Our results show that the percentage of AGE-positive neurons (and astroglia) increase both with age and, in AD patients, with the progression of the disease (Braak stages). Interestingly, nearly all if those neurons which show diffuse cytosolic AGE immunoreactivity also contain hyperphosphoryated tau, suggesting a link between AGE accumulation and the formation of early neurofibrillary tangles. Many, but not all, neurons show a co-localization of AGEs with other markers of neurodegeneration, such as nNOS and caspase-3.