Abnormal accumulation of citrullinated proteins catalyzed by peptidylarginine deiminase in hippocampal extracts from patients with Alzheimer's disease

Citrullinated proteins are the products of a posttranslational process in which arginine residues undergo modification into citrulline residues when catalyzed by peptidylarginine deiminases (PADs) in a calcium ion-dependent manner. In our previous report, PAD2 expressed mainly in the rat cerebrum became activated early in the neurodegenerative process. To elucidate the involvement of protein citrullination in human neuronal degeneration, we examined whether citrullinated proteins are produced during Alzheimer's disease (AD). By Western blot analysis with antimodified citrulline antibody, citrullinated proteins of varied molecular weights were detected in hippocampal tissues from patients with AD but not normal humans. Two of the citrullinated proteins were identified as vimentin and glial fibrillary acidic protein (GFAP) by using two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry. Interestingly, PAD2 was detected in hippocampal extracts from AD and normal brains, but the amount of PAD2 in the AD tissue was markedly greater. Histochemical analysis revealed citrullinated proteins throughout the hippocampus, especially in the dentate gyrus and stratum radiatum of CA1 and CA2 areas. However, no citrullinated proteins were detected in the normal hippocampus. PAD2 immunoreactivity was also ubiquitous throughout both the AD and the normal hippocampal areas. PAD2 enrichment coincided well with citrullinated protein positivity. Double immunofluorescence staining revealed that citrullinated protein- and PAD2-positive cells also coincided with GFAP-positive cells, but not all GFAP-positive cells were positive for PAD2. As with GFAP, which is an astrocyte-specific marker protein, PAD2 is distributed mainly in astrocytes. These collective results, the abnormal accumulation of citrullinated proteins and abnormal activation of PAD2 in hippocampi of patients with AD, strongly suggest that PAD has an important role in the onset and progression of AD and that citrullinated proteins may become a useful marker for human neurodegenerative diseases.     

Deletion of N-terminus of human tyrosine hydroxylase type 1 enhances stability of the enzyme in AtT-20 cells

Wildtype human tyrosine hydroxylase (TH) type 1 and 4 mutants (del-52, a form with the first 52 amino acid residues deleted; del-157, one with the first 157 amino acid residues deleted; RR-EE, one in which Arg37-Arg38 was replaced by Glu37-Glu38; and S40D, one in which Ser40 was replaced by Asp40) were expressed in AtT-20 mouse neuroendocrine cells in order to clarify how deeply the N-terminus of TH is involved in the efficient production of dopamine (DA) in mammalian cells. The amounts of DA that accumulated in AtT-20 cells expressing these human TH type 1 (hTH1) phenotypes were in the following order: del-52 = del-157 = RR-EE > S40D > wildtype, although the enzyme activities of del-52 and del-157 were lower than those of wildtype, RR-EE, and S40D. The observation on immunoblot analyses that the N-terminus-deleted hTH1 mutants were much more stable than wildtype can reconcile the discrepant results. Computer-assisted analysis of the spatial configuration of hTH1 identified five newly recognized PEST motifs, one of which was located in the N-terminus sequence of Met1-Lys12 and predicted that deletion of the N-terminus region would alter the secondary structure within the catalytic domain. Collectively, the high stability of the N-terminus-deleted hTH1 mutants can be generated by the loss of a PEST motif in their N-termini and the structural change in the catalytic domain, which would promise an efficient production of DA in mammalian cells expressing N-terminus deleted hTH1.     

A case of angiolymphoid hyperplasia with eosinophilia (ALHE) of the upper lip

Angiolymphoid hyperplasia with eosinophilia (ALHE) is clinically characterized by intradermal or subcutaneous papules and/or nodules usually occurring in young adults. Lesions in the oral mucosa are extremely rare. We report a case and review the literature of ALHE cases involving the oral mucosa. A 40-year-old man presented with a painless, 20 x 20 mm, submucosal nodule on the upper lip. Histological examination of lip biopsy specimens revealed an increase in many small vessels. The vascular walls consisted of prominent endothelial cells with a histiocytoid appearance, which protruded into the lumen. Many eosinophils and lymphocytes were also seen around the vessels. The diagnosis of ALHE was made from the above findings.     

The "pulvinar sign" in a case of paraneoplastic limbic encephalitis associated with non-Hodgkin's lymphoma

This paper reports a 59 year old woman with paraneoplastic limbic encephalitis associated with diffuse large B cell lymphoma. Her brain magnetic resonance imaging scan showed bilateral posterior thalamic hyperintensities, similar to the "pulvinar sign". Her symptoms included progressive psychiatric disturbance and resembled the initial symptoms of variant Creutzfeldt-Jakob disease (vCJD). Clinicians should consider this treatable disorder in the differential diagnosis of vCJD.     

The metabolic syndrome: prevalence and risk factors in the urban population of Ho Chi Minh City

The purpose of this study was to determine the prevalence of metabolic syndrome (MeS) and its risk factors in urban population of Ho Chi Minh City. A cross-sectional study was conducted in urban areas of Ho Chi Minh City with 611 participants. The demographic, socio-economic details, anthropometric indexes and blood pressure were recorded. A fasting blood sample was collected for the analyses of glucose, total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). MeS was defined by presence of three or more of the following components: abdominal obesity, hypertriglyceridemia, low HDL-cholesterolemia, high blood pressure and high fasting plasma glucose. The crude prevalence of MeS was 18.5% (95% CI: 15.5-21.9). After age, sex standardization, this prevalence was 12.0% (95% CI: 10.9-13.2). The prevalence increased with age and sedentary work. Subjects with MeS had significantly higher body fat percentage than that of normal subjects. Metabolic syndrome showed a positive association with age, body fat percentage and sedentary occupation. This first study on MeS showed that 12% adults in urban areas of Ho Chi Minh City had metabolic syndrome. It suggests that MeS is becoming a noteworthy health problem in Vietnam and to the early detection and appropriate intervention as well as healthy lifestyle education programs need to be established.