Assessment of Urinary Betaine as a Marker of Diabetes Mellitus in Cardiovascular Patients

Abnormal urinary excretion of betaine has been demonstrated in patients with diabetes or metabolic syndrome. We aimed to identify the main predictors of excretion in cardiovascular patients and to make initial assessment of its feasibility as a risk marker of future diabetes development. We used data from 2396 patients participating in the Western Norway B-vitamin Intervention Trial, who delivered urine and blood samples at baseline, and in the majority at two visits during follow-up of median 39 months. Betaine in urine and plasma were measured by liquid-chromatography-tandem mass spectrometry. The strongest determinants of urinary betaine excretion by multiple regression were diabetes mellitus, age and estimated glomerular filtration rate; all p<0.001. Patients with diabetes mellitus (n = 264) had a median excretion more than three times higher than those without. We found a distinct non-linear association between urinary betaine excretion and glycated hemoglobin, with a break-point at 6.5%, and glycated hemoglobin was the strongest determinant of betaine excretion in patients with diabetes mellitus. The discriminatory power for diabetes mellitus corresponded to an area under the curve by receiver-operating characteristics of 0.82, and betaine excretion had a coefficient of reliability of 0.73. We also found a significant, independent log-linear relation between baseline betaine excretion and the risk of developing new diabetes during follow-up. The good discriminatory power for diabetes, high test-retest stability and independent association with future risk of new diabetes should motivate further investigation on the role of betaine excretion in risk assessment and long-term follow-up of diabetes mellitus.     

Plectin–intermediate filament partnership in skin, skeletal muscle, and peripheral nerve

Plectin is a large, 500-kDa, intermediate filament (IF)-associated protein. It acts as a cytoskeletal crosslinker and signaling scaffold, affecting mechanical as well as dynamic properties of the cytoskeleton. As a member of the plakin family of cytolinker proteins, plectin has a multidomain structure that is responsible for its vast binding portfolio. It not only binds to all types of IFs, actin filaments and microtubules, but also to transmembrane receptors, proteins of the subplasma membrane protein skeleton, components of the nuclear envelope, and several kinases with known roles in migration, proliferation, and energy metabolism of cells. Due to alternative splicing, plectin is expressed as various isoforms with differing N-terminal heads that dictate their differential subcellular targeting. Through specific interactions with other proteins at their target sites and their ability to bind to all types of IFs, plectin molecules provide strategically located IF anchorage sites within the cytoplasm of cells. In this review, we will present an overview of the structural features and functional properties of plectin and discuss recent progress in defining the role of its isoforms in stress-prone tissues and the implicated diseases, with focus on skin, skeletal muscle, and Schwann cells of peripheral nerve.     

FGF2 effects in periosteal fibroblasts bearing the FGFR2 receptor Pro253 Arg mutation

AIM: A growing number of mutations mapped in the receptor gene for fibroblast growth factor have been implicated in several cranial development disorders including the Apert and Crouzon syndromes. The present paper investigated cellular mechanisms underlying Apert phenotype, by analyzing the effects of FGF2 in primary cultures of Apert periosteal fibroblasts carrying the FGFR2 Pro253Arg mutation. RESULTS: FGF2 administration significantly decreased extracellular matrix production in mutant cells by stimulating degradative enzymatic activities. Gene expression analysis revealed that decorin and biglycan, two proteoglycans involved in collagen fibrillogenesis, were more expressed in mutant cells and down-regulated by FGF2. FGF2 receptor binding showed little differences in high affinity receptor counts between mutant and wild-type cells, while we showed for the first time that low affinity receptors are significantly fewer in mutant cells. Differences were found in Crouzon syndrome, where both high and low affinity receptor counts were up-regulated. CONCLUSIONS: The different mutation and low affinity receptor regulation in mutant receptors support the hypothesis that the impact on the activity of the ligand-receptor complex could allow distinct modes of FGF2 activation in Apert and Crouzon syndromes, which interfere with the FGFR2 signalling cascade.     

Prevalence, genotype distribution and persistence of human papillomavirus in oral mucosa of women: a six-year follow-up study

Background

Human papillomavirus (HPV) infections have been linked to a subset of oral and oropharyngeal cancers. However, little is known on the natural history of oral HPV infections. We designed the prospective Finnish HPV Family Study to assess the dynamics of HPV infections in parents and their infants. This study reports HPV genotype distribution and virus persistence in oral mucosa of the mothers.

Materials and Methods

Totally, 324 pregnant women were enrolled at the 3^rd trimester of pregnancy and followed-up for 6 years. Oral scrapings taken with a brush were collected and HPV-genotyping was performed with nested PCR and Multimetrix® test (Progen, Heidelberg, Germany). The predictors of persistent oral HPV species 7/9 infections were analyzed using generalized estimating equation models.

Results

The point prevalence of oral HPV varied from 15% to 24% during the 6-year follow-up. Altogether, 18 HPV genotypes were identified either as single or multiple-type oral infections. HPV16 was the most prevalent type at 9.7%–18.4%, followed by HPV18, HPV6, and multiple infections. Altogether, 74 women had persistent oral HPV infection determined as at least two consecutive samples positive with the same HPV genotype. HPV16 and HPV6 were the two most frequent types to persist (76% and 9%) for a mean of 18.6 and 20.2 months, respectively, followed by multiple infections (8%) for 18.3 months. An increased risk for persistent oral HPV infection with species 7/9 was associated with being seropositive for low-risk (LR)-HPV-types at baseline, whereas the use of oral contraceptives and a second pregnancy during follow-up were protective. Clinical oral lesions were detected in 17% of these women, one-third of whom had persistent oral HPV-infections.

Conclusion

HPV16 and HPV6 were the most common genotypes in oral HPV-infections and were also most likely to persist. Use of oral contraceptives and a second pregnancy protected against oral HPV persistence.     

Synthesis and heme-binding correlation with antimalarial activity of 3,6-bis-(omega-N,N-diethylaminoamyloxy)-4,5-difluoroxanthone

In this study, the effect of fluorine upon the heme-binding ability of the xanthone nucleus was investigated for 3,6-bis-(omega-N,N-diethylaminoamyloxy)-4,5-difluoroxanthone (F2C5). 2-Fluoro-1,3-dimethoxybenzene was prepared by a new, improved method and used to build up the xanthone nucleus. The interaction of F2C5 with heme was investigated by UV-vis, (1)H NMR, and (19)F NMR spectroscopy. For the first time, NMR studies for the heme-drug interactions are carried out at pH 5.0, physiological for the acidic food vacuole of the malaria parasite.     

Bronchial branching correlates with specific glycosidase activity, extracellular glycosaminoglycan accumulation, TGF beta(2), and IL-1 localization during chick embryo lung development.

During organ differentiation, cell-extracellular matrix (ECM) interactions are required. The components of the ECM, such as glycosaminoglycans, fibronectin, laminin, and collagens, change in relation to cytokine and enzyme activity. Moreover, glycosaminoglycans (GAGs) are components of the ECM that play an important role in both cytokine regulation and cell activities. In this work we studied the accumulation of hyaluronic acid and chondroitin sulfate and heparan sulfate proteoglycans (PGs), beta-N-acetyl-D-glucosaminidase activity, the presence of transforming growth factor beta(2) (TGF beta(2)), and interleukin-1 (IL-1), and the localization of fibronectin, laminin, and collagen I and IV during the early stages of chick embryo lung development. We also determined the levels of hyaluronic acid, chondroitin sulfate, dermatan sulfate, and heparan sulfate GAGs and the activity of beta-N-acetyl-D-glucosaminidase with biochemical methods. Our data show that beta-N-acetyl-D-glucosaminidase activity increases in each cell, especially in the epithelial growth front at the emergence of each bronchial bud, where hyaluronic acid and IL-1 are located in the surrounding mesenchymal areas. Chondroitin sulfate and heparan sulfate PGs, fibronectin, laminin, and collagen I and IV are evident in the area near the basal membrane along the sides where the forming structures are stabilized. Biochemical data show that beta-N-acetyl-D-glucosaminidase activity increases in cells during lung development and is related to GAG decrease and to modifications of the nonsulfated/sulfated GAG ratio. These modifications could change cytokine activity and play an important role in bronchial branching development.     

Association and linkage of the dopamine transporter gene and attention-deficit hyperactivity disorder in children: heterogeneity owing to diagnostic subtype and severity.

Attention-deficit hyperactivity disorder (ADHD) affects approximately 3%-5% of children in the United States. In the current psychiatric nomenclature, ADHD comprises three subtypes: inattentive, hyperactive-impulsive, and combined. In this study, we used four analytic strategies to examine the association and linkage of the dopamine transporter gene (DAT1) and ADHD. Our sample included 122 children referred to psychiatric clinics for behavioral and learning problems that included but were not limited to ADHD, as well as their parents and siblings. Within-family analyses of linkage disequilibrium, using the transmission disequilibrium test (TDT), confirmed the 480-bp allele as the high-risk allele. In between-family association analyses, levels of hyperactive-impulsive symptoms but not inattentive symptoms were related to the number of DAT1 high-risk alleles. Siblings discordant for the number of DAT1 high-risk alleles differed markedly in their levels of both hyperactive-impulsive and inattentive symptoms, such that the sibling with the higher number of high-risk alleles had much higher symptom levels. Within-family analyses of linkage disequilibrium, using the TDT, suggested association and linkage of ADHD with DAT1 and that this relation was especially strong with the combined but not the inattentive subtype. The relation of DAT1 to ADHD increased monotonically, from low to medium to high levels of symptom severity. Our results replicate and extend previous findings of the association between the DAT1 gene and childhood ADHD. This represents one of the first replicated relations of a candidate gene and a psychiatric disorder in children.     

Organization, nucleation, and acetylation of microtubules in Xenopus laevis oocytes: a study by confocal immunofluorescence microscopy

Anti-tubulin immunofluorescence and laser-scanning confocal microscopy were used to examine microtubule organization during Xenopus oogenesis (Dumont stages I-VI). Stage I oocytes contained a poorly ordered microtubule array, characterized by concentrations of microtubule in the cortex, surrounding the germinal vesicle, and associated with the mitochondrial mass. No focus of microtubule organization was detectable by optical sectioning or in microtubule regrowth experiments, suggesting that stage I oocytes lack a functional MTOC. The microtubule array becomes progressively more complex and polarized during oogenesis; an extensive array of microtubules and microtubule bundles was apparent in the animal hemisphere of stage VI oocytes, and a less ordered array was observed in the vegetal hemisphere. A dense network of microtubules surrounded the germinal vesicle, apparently extending from a tubulin- and microtubule-rich region of cytoplasm adjacent to the vegetal surface of the GV. The organization of microtubules in normal oocytes, in oocytes recovering from cold-induced microtubule depolymerization, and in enucleated oocytes, suggested that the germinal vesicle serves as an MTOC in stage VI oocytes. Antibodies to acetylated alpha-tubulin revealed numerous acetylated, presumably stable, microtubules in stage I and stage VI oocytes. The array of oocyte microtubules thus might function as a stable framework for the localization of developmentally important molecules and organelles during oogenesis.