Oligodendrocyte maturation is inhibited by bone morphogenetic protein

Mature oligodendrocytes myelinate axons in the CNS. The development of the myelin sheath is dependent on the proper maturation of oligodendrocytes from precursors cells, a spatially restricted process that is regulated by inductive and repressive cues. Several members of the bone morphogenetic protein family (BMP2 and 4) have been implicated as repressors of oligodendrocyte development in vitro by shifting oligodendrocyte precursors into the astrocyte lineage. We now report on a second role of BMPs in oligodendrocyte development, regulation of myelin protein expression in immature oligodendrocytes. Purified immature rodent oligodendrocytes treated with BMP4 maintained galactocerebroside (GalC) expression, whereas the expression of three key myelin proteins, proteolipid protein (PLP), myelin basic protein (MBP), and 2'-3'-cyclic nucleotide 3'-phosphodiesterase (CNP), was severely decreased. Paradoxically, BMP-treated oligodendrocytes show increased process extension and complexity, normally a feature of oligodendrocyte maturation. We also investigated whether BMP4 could inhibit myelin protein expression in an E 12.5 mouse explant culture of cervical spinal cord and hindbrain that maintains the in vivo cellular relationships and architecture. Beads soaked in BMP protein implanted into these explants inhibited the expression of myelin proteins, proteolipid protein, and myelin-associated glycoprotein (MAG), in the local area surrounding the bead. Since these explants also contained precursors cells, expression of galactocerebroside and O4, an oligodendrocyte marker, were also decreased by BMP treatment but to a much lesser degree than the myelin markers. Together, these data indicate that BMPs have multiple roles in oligodendrocyte development. At earlier stages, they affect cell lineage decisions and at later stages, they inhibit cell specialization.     

Polymeric complexes of lidocaine hydrochloride with poly(acrylic acid) and poly(2-hydroxyethyl vinyl ether)

The specific interactions of local anesthetic lidocaine hydrochloride with poly(acrylic acid) and poly(2-hydroxyethyl vinyl ether), as well as in a triple system composed of the drug and both polymers, have been studied in aqueous solutions by viscometric, turbidimetric, potentiometric, and FTIR spectroscopic methods. The mechanism of the drug binding to the polymers and the structures of the polycomplexes formed are clarified.     

Vulnerable atherosclerotic plaque: clinical implications

Coronary Artery Disease (CAD) remains globally the leading cause of death and long-term morbidity. Among the many manifestations of CAD, acute coronary syndrome (ACS), ranging from unstable angina to acute myocardial infarction, is the most catastrophic event due to our inability to predict its occurrence. Despite improved treatments of CAD, ACS results in sudden death or permanent disability in a substantial percentage of patients. If we could predict the timing of ACS or better yet prevent its occurrence, we could alter the otherwise unfavorable course of CAD. Several studies have convincingly demonstrated that majority of all ACS develops from previously mild to moderate stenoses. Thus, based on these and autopsy studies, sudden disruption or rupture of the non-obstructive "vulnerable" atherosclerotic lesion is currently considered the cause of ACS. Recent clinical studies have substantiated earlier autopsy observations that plaque vulnerability is a systemic process, involving multiple locations concurrently. Although the exact inciting factors of the vulnerable plaque rupture are unknown, inflammation is accepted to be a pivotal event. The possibility of stabilizing the vulnerable plaques has strongly been supported by the lipid lowering trials, in which dramatic reduction of the acute coronary events was noted despite subtle improvements in luminal diameter. Furthermore, antiplatelet therapies have become an important preventative therapy due to the essential role of platelets in the aftermath of plaque rupture. Finally, various imaging modalities to diagnose the plaque vulnerability could help prevent the acute coronary events in the future.     

Mucosa-associated lymphoid tissue lymphoma of the thymus resected using combined thoracoscopic and transcervical approaches

Mucosa-associated lymphoid tissue (MALT) lymphoma is a low-grade variant of B cell lymphoma that arises in extranodal tissue of the gastrointestinal tract, lung, salivary gland, thyroid, or other organ derived from the foregut. However, MALT lymphoma in the thymus is extremely rare. We report a case of thymic MALT lymphoma, extending to the neck, resected using combined thoracoscopic and transcervical approaches. To the best of our knowledge, thoracoscopic management of MALT lymphoma in the thymus has not previous been reported.     

Intraoperative complications of thoracoscopic surgery for mediastinal tumors

We report intraoperative complications of thoracoscopic surgery for mediastinal tumors. Forty cases of mediastinal tumor were undergone thoracoscopic surgery at the hospital from 1999 to 2002. The patient's ages ranged from 18 to 74 years old with a mean of 47.7. Location of these tumors were anteriormediastinal in 20 cases, middlemediastinal in 6 cases, posteriormediastinal in 11 cases, and superiormediastinal in 3 cases. Intraoperative complications were rupture of the cyst in 9 cases, bleeding over 150 ml in 5 cases, injury of lung caused by adhesiolysis in 5 cases, and injury of nerve in 3 cases. The mean operation time was 103.8 minutes. Postoperative hospital stay ranged from 2 to 22 days with a mean of 5.9 days. All are alive with no recurrences or postoperative complications.     

Mutations of the BAK gene are infrequent in advanced gastric adenocarcinomas in Koreans

The bcl-2 homologue antagonist/killer (BAK) is a potently apoptosis-inducing gene and plays an important role in modulating apoptosis in epithelial cells. We have analyzed the mutation of the entire coding region of BAK gene in 107 Korean advanced gastric adenocarcinomas by polymerase chain reaction-single strand conformation polymorphism and sequencing. Homozygous deletions were not found in these samples. Only three cases of 107 gastric adenocarcinomas (2.8%) exhibited the BAK mutations. Two of them exhibited missense mutations and the remaining one had a silent mutation. All of these mutations were exclusively detected in exon 2. Mutations in the BAK gene were observed only in advanced gastric adenocarcinomas with extensive metastases of regional lymph nodes. The data presented here suggest that the mutations of BAK gene rarely occurred in advanced gastric adenocarcinomas.     

Glycyrrhizin ameliorates renal function defects in the early-phase of ischemia-induced acute renal failure

The aim of this study was to investigate the effect of glycyrrhizin administration (200 mg/kg/day) on renal function parameters in the early-phase of ischaemia-reperfusion induced acute renal failure (ARF) in rats. The present study showed that the urinary fl ow rate in ischaemia-ARF was significantly increased in association with decreases in water balance, urinary sodium excretion and urine osomolality, which were partially restored by administration of glycyrrhizin. Both solute-free water reabsorption (T(c)H2O) and creatinine clearance (Ccr) were significantly decreased in rats subjected to ischaemia-reperfusion for 72 h compared with the control. Histopathological examination of the kidneys from ARF rats at 72 h after release of the bilateral renal artery clamping, showed that the glomerulus, proximal tubules and distal tubules were severely disrupted and left a denuded basement membrane. When glycyrrhizin was administered in rat ARF for 72 h, Ccr reached almost 96% compared with that of the sham-operated control rats and T(c)H2O was improved by 47% compared with that of the ischaemia-ARF rats. The lesions in the glomerulus, proximal and distal tubule of the renal cortex were also restored by the administration of glycyrrhizin. Taken together, glycyrrhizin administration ameliorates both renal function defects, especially the renal concentrating ability, and structural lesions in renal tissues in rats in the early-phase of ischaemia-ARF.