Nucleotide sequences of the proA and proB genes of Treponema pallidum, the syphilis agent

Melatonin has previously been reported to influence cell differentiation and growth in a number of cell culture systems in vitro. In this paper, we describe the effects of high pharmacological and low physiological concentrations of melatonin on cell growth in rat pheochromocytoma cells (PC12 cells). Melatonin produced a biphasic response with respect to cell growth in PC12 cells. At low concentrations (1-10 nM) melatonin suppressed PC12 cell growth whereas at higher concentration (10 microM) it prevented cell death. Cultures treated with high concentrations of melatonin displayed an increase in cell number and a decreased release of lactic acid dehydrogenase (LDH) into the culture media, indicating that melatonin was enhancing cell survival as opposed to stimulating cell proliferation. Inhibition of cell death by high concentrations of melatonin was both time and concentration-dependent and did not require the continued presence of melatonin throughout the entire time of incubation. These studies suggest melatonin is preventing either apoptosis or programmed cell death. In contrast, concentrations of melatonin (1-10 nM) at or near the binding affinity for the nuclear receptor, RZRbeta, suppressed PC12 cell growth. At these concentrations, melatonin failed to inhibit forskolin-induced cAMP formation and process outgrowth as well as prevent forskolin suppression of cell growth. These data indicate that PC12 cells probably lack functionally active cell surface receptors for melatonin and suggest the interaction of melatonin with the nuclear receptor may be responsible for suppression of PC12 cell growth.     

Advanced strain engineering for state-of-the-art nanoscale CMOS technology

The introduction and advancement of strain engineering has been one of the most critical features for the state-of-the-art nanoscale CMOS transistors. This paper provides an overview of the major strain engineering techniques that have remarkably re-shaped the advanced CMOS transistor architecture, including embedded SiGe (eSiGe), embedded Si:C (eSi:C), stress memorization technique (SMT), dual stress liners (DSL), and stress proximity technique (SPT). The advent of high-K/metal-gate (HKMG) also brings in a...     

Expression of BDNF and trkB as a function of age and cognitive performance

The expression of the neurotrophic factor BDNF increases during learning-related events and is decreased in the hippocampus of Alzheimer's Disease patients, suggesting that it plays a role in learning, memory, and/or age-related memory deficits. We examined the expression of BDNF and its high affinity receptor, trkB, in young and aged Sprague-Dawley rats. BDNF and trkB mRNA were measured by semi-quantitative in situ hybridization and BDNF protein was measured by ELISA. Significant decreases with age were detected for BDNF mRNA in the pons, BDNF protein in the midbrain, and trkB mRNA in many areas of the brain. Rats were evaluated on the Morris water maze before sacrifice so that BDNF and trkB levels could be related to cognitive status. Regression analyses revealed that decreased trkB mRNA in the pons significantly predicted impaired memory performance in aged rats. These results suggest that decreases in trkB mRNA with age are more widespread than decreases in BDNF, and that BDNF decreases are restricted to more caudal brain regions.     

Video-assisted thoracoscopic surgery for spontaneous hemopneumothorax

PURPOSE: This study examined the usefulness of magnetic resonance imaging (MRI) in assessing whether parotid tumors were located in the superficial or deep lobe. PATIENTS AND METHODS: Eight patients with parotid gland tumors underwent MRI using a spin echo pulse sequence. T1- and T2-weighted images were obtained. To assess tumor localization in the parotid gland, two anatomic landmarks were used: 1) a line connecting the lateral surface of posterior belly of digastric muscle and lateral surface of the cortical bone of ascending ramus (facial nerve [FN] line) and 2) the relationship to the retromandibular vein (RV). Results of all MRI examinations were compared with the surgical findings. RESULTS: Seven of eight cases were correctly diagnosed using the FN line criterion. Five of eight cases were correctly diagnosed using the RV criterion. CONCLUSION: MRI is an excellent modality to show tumor localization in the parotid gland.     

14-3-3 proteins are required for maintenance of Raf-1 phosphorylation and kinase activity

By binding to serine-phosphorylated proteins, 14-3-3 proteins function as effectors of serine phosphorylation. The exact mechanism of their action is, however, still largely unknown. Here we demonstrate a requirement for 14-3-3 for Raf-1 kinase activity and phosphorylation. Expression of dominant negative forms of 14-3-3 resulted in the loss of a critical Raf-1 phosphorylation, while overexpression of 14-3-3 resulted in enhanced phosphorylation of this site. 14-3-3 levels, therefore, regulate the stoichiometry of Raf-1 phosphorylation and its potential activity in the cell. Phosphorylation of Raf-1, however, was insufficient by itself for kinase activity. Removal of 14-3-3 from phosphorylated Raf abrogated kinase activity, whereas addition of 14-3-3 restored it. This supports a paradigm in which the effects of phosphorylation on serine as well as tyrosine residues are mediated by inducible protein-protein interactions.     

Ag<Subscript>3</Subscript>Sn plate formation in the solidification of near-ternary eutectic Sn-Ag-Cu

Near-ternary eutectic Sn-Ag-Cu alloys are leading lead-free candidate solders for various applications. These alloys yield three phases upon solidification: β-Sn,Ag₃Sn, and Cu₆Sn₅. Large, plate-like, pro-eutectic Ag₃Sn structures can grow rapidly within the liquid phase, potentially adversely affecting the mechanical behavior and reducing the fatigue life of solder joints. This article reports on the formation of such plates in Sn-Ag-Cu solder balls and joints and demonstrates how large Ag₃Sn plate formation can be minimized. For more information, contact S.K. Kang, IBM T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598; (914) 945-3932; fax (914) 945-2141; e-mail kang@us.ibm.com.     

Pigmentary diseases

Abnormalities of pigmentation are common and frequently produce great concern in patients presenting to primary care physicians. Although many pigmentary changes arise as a consequence of inflammatory skin disorders, it is important to differentiate a primary skin disease from postinflammatory changes. Early recognition of a pigmentary disease allows the clinician to begin appropriate therapy at a stage when medical intervention may be more effective. Although many skin disorders are mainly of cosmetic concern, the condition may be devastating psychologically, requiring the clinician to be sensitive to the overall impact of the disorder and treat it accordingly.