CD11b expression distinguishes sequential stages of peritoneal B-1 development

Peritoneal cavity (PerC) B-1 cells have long been known to express CD11b, which is coexpressed with CD18 to form the Mac-1/CR3 complement receptor and adhesion molecule. However, although all PerC B-1 cells are commonly believed to express CD11b, we show here that nearly half of the cells in each of the PerC B-1 subsets (B-1a and B-1b) do not express this surface receptor. The CD11b(+) cells in each B-1 subset are larger and more granular and express higher levels of surface IgM than the CD11b(-) B-1 cells. In addition, the CD11b(+) B-1 cells initiate the formation of tightly associated doublets that are present at high frequency in adult PerC. Finally, and most importantly from a developmental standpoint, the CD11b(+) B-1 cells have a limited reconstitution capability: when sorted and transferred into congenic recipients, they reconstitute their own (CD11b(+)) B-1 subset but do not reconstitute the CD11b(-) B-1 subset. In contrast, CD11b(-) B-1 cells transferred under the same conditions efficiently replenish all components of the PerC B-1 population in appropriate proportions. During ontogeny, CD11b(-) B-1 cells appear before CD11b(+) B-1 cells. However, the clear phenotypic differences between the neonatal and adult CD11b B-1 subsets argue that although CD11b(-) B-1 give rise to CD11b(+) B-1 in both cases different forces may regulate this transition.     

German new onset diabetes in the young incident cohort study: DiMelli study design and first-year results

BACKGROUND: Diabetes incidence in childhood and youth is increasing worldwide, including autoimmune and non-autoimmune cases. Recent findings suggest that there is a larger than expected proportion of type 2 diabetes in youth, and potential cases of intermediate diabetes phenotypes. Most pediatric diabetes registries focus on type 1 diabetes. Also, there is an absence of reliable data on type 2 diabetes incidence in youth. AIMS: The DiMelli study aims to establish a diabetes incidence cohort registry of patients in Germany, diagnosed with diabetes mellitus before age 20 years. It will be used to characterize diabetes phenotypes by immunologic, metabolic, and genetic markers. DiMelli will assess the contribution of obesity and socio-demographic factors to the development of diabetes in childhood and youth. METHODS: Recruitment of patients started in 2009, and is expected to continue at a rate of 250 patients per year. RESULTS: 84% of the 216 patients recruited within the first year were positive for multiple islet autoantibodies, 12% for one islet autoantibody, and 4% were islet autoantibody-negative. Patients with multiple islet autoantibodies were younger and had lower fasting C-peptide levels, compared to islet autoantibody-negative patients (median age 10.0 vs. 14.1 years, p < 0.01). CONCLUSIONS: Results from the first year of the study show that DiMelli will help to reveal new knowledge on the etiology of diabetes, and the contribution of genetic predisposition and environmental risk factors to the different types of diabetes.     

N-Acetylcysteine--a safe antidote for cysteine/glutathione deficiency

Glutathione (GSH) deficiency is associated with numerous pathological conditions. Administration of N-acetylcysteine (NAC), a cysteine prodrug, replenishes intracellular GSH levels. NAC, best known for its ability to counter acetaminophen toxicity, is a safe, well-tolerated antidote for cysteine/GSH deficiency. NAC has been used successfully to treat GSH deficiency in a wide range of infections, genetic defects and metabolic disorders, including HIV infection and COPD. Over two-thirds of 46 placebo-controlled clinical trials with orally administered NAC have indicated beneficial effects of NAC measured either as trial endpoints or as general measures of improvement in quality of life and well-being of the patients.     

PCR Diagnosis of Opisthorchis viverrini and Haplorchis taichui Infections in a Lao Community in an Area of Endemicity and Comparison of Diagnostic Methods for Parasitological Field Surveys

Opisthorchiasis is a major public health problem in Southeast Asia. Affected individuals often have mixed infections with the liver fluke Opisthorchis viverrini and minute intestinal flukes such as Haplorchis taichui. The usual methods of diagnosing these infections involve the demonstration of fluke eggs in stool samples under light microscopy, but sensitivity and specificity are low. We developed two PCR tests that detect and discriminate between O. viverrini and H. taichui infections. PCR tests were validated by stool samples from purged individuals. We then applied the PCR tests to estimate the prevalence of O. viverrini and H. taichui infections from a random sample of individuals selected from a community in an area of endemicity in Khong District, Laos. PCR results were compared with those from the Kato-Katz (KK) method and the formalin-ether concentration technique (FECT). When validated with purge results, PCR tests of O. viverrini and H. taichui had sensitivities of 93.7% (95% confidence interval [CI], 85.8 to 97.9%) and 73.3% (95% CI, 60.3 to 83.9%) and could detect as little as 0.75 pg DNA and 1.32 ng DNA, respectively. The PCR-determined community prevalences of O. viverrini and H. taichui infections were 63.9% (95% CI, 54.1 to 72.9%) and 30.6% (95% CI, 22.1 to 40.2%), respectively. Using PCR as the gold standard to detect O. viverrini, three KK thick smears performed comparably well, whereas one KK smear and FECT were poorer (sensitivities of 91.4% [95% CI, 81.0 to 97.1%,], 62.3% [95% CI, 49.8 to 73.7%], and 49.3% [95% CI, 37.0 to 61.6%], respectively). PCR may be a valuable and sensitive diagnostic tool, particularly for low-intensity O. viverrini and H. taichui infections.Food-borne trematodiases are an emerging but neglected public health issue (12). One of the food-borne trematodes, the liver fluke Opisthorchis viverrini is endemic in Cambodia, Lao People''s Democratic Republic (PDR), Thailand and Viet Nam (8). It has been estimated that the number of infections caused by O. viverrini amounts to 9 million cases, and more than 67 million people are at risk of infection (11). Chronic O. viverrini infection is an important risk factor (class 1 carcinogen) for developing cholangiocarcinoma, or biliary duct cancer, which is associated with a poor prognosis (17, 24-26).O. viverrini infection often coexists with other food-borne trematodes, including several species of flukes called the minute intestinal flukes (MIF) owing to their small size (families Heterophyidae and Lecithodendriidae). In recent studies in Lao PDR (2, 4, 23), different species of MIF were detected after purging individuals infected with O. viverrini. Of these MIF, Haplorchis taichui was the predominant species in concurrent infection with O. viverrini. The coexistence of O. viverrini with H. taichui infections has been described previously (7, 21, 29).Fecal examination under light microscopy is currently the standard method to diagnose O. viverrini infections. The Kato-Katz technique (KK) (10) is the recommended field method (34). This technique permits estimation of infection intensity expressed in eggs per gram feces (epg). Unfortunately, a single stool examination read under light microscopy has low sensitivity (24), particularly for low-intensity infections, and examination of repeated specimens per individual may be needed to improve detection rates. Furthermore, KK does not permit the differentiation of O. viverrini eggs from MIF eggs such as those of H. taichui, because the eggs are similar in size and are both oval and operculated (30). Detection by light microscopy is also operator dependent, and infection may simply be missed.When screening for O. viverrini by KK under light microscopy, identified eggs can be characterized only as “Opisthorchis-like” (21, 29). Distinction of O. viverrini eggs from MIF eggs can be achieved if the specimen is preserved and examined by the formalin-ether concentration technique (FECT) and if the eggs are later stained with iodine (9), potassium permanganate (28), or methylene blue (20). One method of confirming O. viverrini infections in the presence or absence of MIF with certainty is by identification of adult flukes, which may be obtained by treating infected individuals with praziquantel, the current drug of choice, offering them bowel purging with an oral laxative and then examining their diarrhetic stools.As an alternative to microscopy and its limitation of potential diagnostic misclassification, molecular methods have recently been developed. A PCR method for the detection of O. viverrini eggs in human stool specimens was developed (37) and then evaluated as a diagnostic tool with human stool samples collected in Lao PDR (27). A rapid cleanup procedure for human stool samples was developed using inexpensive chemicals (19). This test recognizes all opisthorchiids by a single assay and differentiates them from MIF. Most recently, PCR tests were developed to discriminate between O. viverrini, H. taichui, and another food-borne trematode, Clonorchis sinensis (22, 31, 32). Some studies using PCR tests on human stool samples were validated with light microscopy (27, 32, 33). A more accurate method such as the identification of adult flukes would be valuable to validate PCR tests.In this paper, we present the development of PCR diagnostic tests using sensitive and specific primers to differentiate O. viverrini from H. taichui with PCR tests validated by stool samples from purged individuals. We then used these PCR methods as the gold standard to estimate the infection prevalences of O. viverrini and H. taichui in a random sample drawn from a cross-sectional community survey in Khong District, Lao PDR. Finally, we compared the results of our PCR method with those from two parasitological diagnostic tests, the KK and FECT.     

Beitrag zur Dysostosis multiplex

Ohne ZusammenfassungMit 10 Textabbildungen.Mit Unterstützung der deutschen Forschungsgemeinschaft.     

MYC can induce DNA breaks in vivo and in vitro independent of reactive oxygen species

MYC overexpression is thought to initiate tumorigenesis by inducing cellular proliferation and growth and to be restrained from causing tumorigenesis by inducing cell cycle arrest, cellular senescence, and/or apoptosis. Here we show that MYC can induce DNA breaks both in vitro and in vivo independent of increased production of reactive oxygen species (ROS). We provide an insight into the specific circumstances under which MYC generates ROS in vitro and propose a possible mechanism. We found that MYC induces DNA double-strand breaks (DSBs) independent of ROS production in murine lymphocytes in vivo as well as in normal human foreskin fibroblasts (NHFs) in vitro in normal (10%) serum, as measured by gammaH2AX staining. However, NHFs cultured in vitro in low serum (0.05%) and/or ambient oxygen saturation resulted in ROS-associated oxidative damage and DNA single-strand breaks (SSBs), as measured by Ape-1 staining. In NHFs cultured in low versus normal serum, MYC induced increased expression of CYP2C9, a gene product well known to be associated with ROS production. Specific inhibition of CYP2C9 by small interfering RNA was shown to partially inhibit MYC-induced ROS production. Hence, MYC overexpression can induce ROS and SSBs under some conditions, but generally induces widespread DSBs in vivo and in vitro independent of ROS production.     

The association between environmental lead exposure and bone density in children

Osteoporosis is a decrease in bone mineral density (BMD) that predisposes individuals to fractures. Although an elderly affliction, a predisposition may develop during adolescence if a sufficient peak BMD is not achieved. Rat studies have found that lead exposure is associated with decreased BMD. However, human studies are limited. We hypothesized that the BMD of children with high lead exposure would be lower than the BMD of children with low lead exposure. We collected data on 35 subjects; 16 had low cumulative lead exposure (mean, 6.5 microg/dL), and 19 had high exposure (mean, 23.6 micro g/dL). All were African American; there was no difference between the groups by sex, age, body mass index, socioeconomic status, physical activity, or calcium intake. Significant differences in BMD between low and high cumulative lead exposure were noted in the head (1.589 vs. 1.721 g/cm2), third lumbar vertebra (0.761 vs. 0.819 g/cm2), and fourth lumbar vertebra (0.712 vs. 0.789 g/cm2). Contrary to our hypothesis, subjects with high lead exposure had a significantly higher BMD than did subjects with low lead exposure. This may reflect a true phenomenon because lead exposure has been reported to accelerate bony maturation by inhibiting the effects of parathyroid hormone-related peptide. Accelerated maturation of bone may ultimately result in a lower peak BMD being achieved in young adulthood, thus predisposing to osteoporosis in later life. Future studies need to investigate this proposed model.     

Beyond dysfunction: a new view of women's sexual problems

A new theoretical framework and classification system for women's sexual problems, written by feminist clinicians and social scientists, was released in October 2000. Part one critiques the current American Psychiatric Association nomenclature for women's sexual programs. Part two highlights international sexual rights documents. Part three begins with a women-centered definition of sexual problems: "discontent of dissatisfaction with any emotional, physical, or relational aspect of sexual experience" (pp. 228-229). It also provides four categories of causes: (a) sociocultural, political, or economic factors; (b) partner and relationship factors; (c) psychological factors; and (d) medical factors. The document is designed for professionals and the public.     

Hydrosilylation of 1-alkenes with dichlorosilane

Symmetrically and unsymmetrically substituted diorganodichlorosilanes have been prepared by hydrosilylation with dichlorosilane using two different platinum catalysts, i.e., hexachloroplatinic acid (“Speier's catalyst”) and a platinum cyclovinylmethylsiloxane complex. Hydrosilylation of unsubstituted 1-alkenes proved to be very efficient, yielding anti-Markonikov substituted di-n-alkyldichlorosilanes. However, no reaction was observed when electron-deficient 1-alkenes were used. Octacarbonyldicobalt enabled formation of the monoadduct of 1H,1H,2H-perfluoro-1-hexene with dichlorosilane, which was employed in a second hydrosilylation of the olefin. Thus, the anti-Markovnikov diadduct was obtained in 40% overall yield. The two-step synthesis has also been applied successfully to obtain unsymmetrically substituted diorganodichlorosilanes containing nitrile and ether groups.