Actin disassembles reversibly during electrically induced recycling of synaptic vesicles in cultured neurons

We have studied depolarization-induced regulation of actin assembly in exocytotically active areas of dissociated chick sympathetic neurons. Active areas were identified with the fluorescent dye FM1-43 which labels synaptic vesicles that recycle in these regions. Exocytosis (electrically stimulated) was monitored in real time through depletion of FM1-43 fluorescence. To study depolarization-induced disassembly of actin in the FM1-43-stained regions, the cells were fixed after different periods of depolarization and stained with rhodamine phalloidin, which binds preferentially to the filamentous form of actin. In active regions, actin disassembles and reassembles during continuous 2 min depolarization. Actin disassembly that occurs after the first 25 s of depolarization was detected by a reduction in rhodamine phalloidin staining and confirmed by correlative electron microscopy. Immunogold staining revealed that actin is abundant throughout resting terminals. In some experiments, actin filaments were stabilized by loading cells with unlabelled phalloidin before stimulating secretion. Stabilizing the filaments does not alter the initial release but strongly reduces the release rate at later stages. These data are consistent with a model in which partial disassembly of actin filaments is necessary for facilitating the transport of vesicles within the terminal and reassembly is necessary for limiting that movement.     

Proglumide as a morphine adjunct in cancer pain management

PURPOSE: To determine the expression of CD44 isoforms in cultured human trabecular meshwork (HTM) and to discuss their possible relationship with outflow facility. METHODS: CD44 isoform expression in cultured HTM was qualitatively examined using immunohistochemistry and RT-PCR analysis. RESULTS: Immunohistochemistry of cultured HTM showed intense staining with a CD44s antibody, and with antibodies against CD44 exon 7, exon 11-12 and exon 14. By RT-PCR, at least three isoforms of CD44 were expressed in HTM: CD44s, CD44v-III and CD44v-I. CONCLUSIONS: At least three isoforms of CD44 are expressed in the HTM. CD44 may play a role in binding and turnover of hyaluronic acid in the trabecular meshwork, thereby regulating outflow facility.     

Immune responses in patients with T-cell lymphoma treated with an anti-idiotype antibody mimicking a highly restricted T-cell antigen

We generated an IgG1 murine monoclonal anti-idiotype antibody (Ab2) to a highly restricted T-cell antigen designated glycoprotein (gp) 37 that is found on T-cell malignancies but not on normal cells. gp37 is identified by the murine monoclonal antibody SN2 (Ab1) against which the Ab2 was raised. Each of four patients with T-cell lymphoma predominantly confined to the skin received a minimum of four intracutaneous injections of aluminum hydroxide precipitated anti-idiotype murine monoclonal antibody (1 mg/injection) given every 2 weeks. For responding patients, injections were continued on a monthly basis. All tumors were measured along orthogonal major and minor axes, using a ruler and/or calipers, by the same observer. Tumor sizes were documented photographically. Three of the four patients developed specific idiotypic humoral immune responses, and two of the four patients also demonstrated idiotypic cell-mediated responses. Humoral responses included binding of the patients' sera to the anti-idiotype antibody as well as specific inhibition of binding of the SN2 antibody (Ab1) to the anti-idiotype antibody (Ab2). Anti-anti-idiotypic (Ab3) antibody from one patient's serum bound specifically to the gp37-positive cell line MOLT-4 and also to semipurified gp37 antigen. Cell-mediated responses were demonstrated by specific proliferative response to the aluminum hydroxide precipitated anti-idiotype antibody by patients' peripheral blood mononuclear cells. While three of the four patients had extensive disease and did not have clinical responses, one of the patients who had nine discrete skin tumors and peripheral blood involvement without other detectable disease had virtually complete disappearance of the tumors lasting over 11 months. Our results demonstrate that this particular anti-idiotype antibody can induce humoral and cellular immune responses, and at least in one patient led to a meaningful therapeutic response. Future trials should focus on immunocompetent patients with minimal disease.     

Laparoscopic evaluation of liver disease in chronic renal failure prior to renal transplantation

It is not rare that controversial indications about the presence or the expression level of multidrug-resistant (MDR) proteins come out from different laboratories upon examination of identical tumor specimens. Distinct aspects, including the use of weakly discriminating monoclonal antibodies (MAbs) and/or unsuitable techniques and procedures, contribute in generating differences in the MDR phenotype evaluation of cancer cells. In this regard we describe here an innovative immunohistochemical approach for the determination of P-glycoprotein expression in cells and tissues. The method is based on the ability of phage-displayed peptides to mimic antibody epitopes. For this purpose we utilized the phage clone #55, which was affinity-purified from a phage-displayed random-peptide library using the MAb MM4.17 (specific for MDR1-P-glycoprotein) as previously described. This clone has been chosen since it clearly and undoubtedly reacts with its cognate MAb, as was determined by ELISA and dot blot tests. Inhibition of the MAb MM4.17 binding to MDR1-P-glycoprotein-expressing cells could be performed by adding a calibrated concentration of phage clone #55 particles, which mimic MDR1-P-glycoprotein antigen. This methodology can eliminate misleading interpretations concerning the presence and expression level of MDR1-P-glycoprotein and might well contribute in routine clinical determinations of MDR in tumor specimens, thus contributing to our understanding of the basis of the mechanisms of tumor cell resistance to drugs.     

Phasic electrodermal orienting response in chronic schizophrenics: II. Response to auditory signals of varying intensity.

Studied phasic electrodermal orienting response (OR) to brief tones at 60, 75, or 90 db. Results support earlier findings obtained with brief visual stimuli both in retest and in newly recruited Ss among 72 clear and 72 confused chronic schizophrenics and 48 normal controls. Confused Ss showed diminished reactivity to stimuli of low to moderate intensity. A moderate increase in stimulus intensity significantly improved initial OR frequency among confused Ss without affecting response amplitude; further increase brought initial OR amplitude to normal levels. Chronic schizophrenics again showed consistently faster habituation than controls. Results are not attributable to particular diagnostic subgroupings or total time in hospital. While long-hospitalized Ss with a hebephrenic diagnosis are more likely to be confused, it is the fact of confusion itself that is significant in determining OR. Results suggest faster but less detailed assilimation of information among chronic schizophrenics in general, coupled with a defensive attenuation of specific input among confused patients in particular. (30 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of heat treatment and cathodic charging conditions on the hydrogen embrittlement of HP 7075 aluminum alloy

The response of an equiaxed-grained, high-purity 7075 aluminum alloy to hydrogen as a function of heat treatment and temperature of cathodic charging has been studied. Room-temperature (RT) tensile tests following RT or 120 °C cathodic charging revealed that hydrogen embrittlement susceptibility was dependent on both heat treatment and charging conditions. However, intergranular behavior was only observed following RT charging, limited to a zone a few grains deep from the surface. This fracture appearance has been considered in terms of the possible formation of an aluminum- or magnesium-base hydride at room temperature, compounds which are thermodynamically unstable at the 150 °C charging temperature. Reasons for the observed embrittlement following high-temperature charging are also considered. Formerly with Carnegie Mellon University.     

Structural Chemistry,Fuzzy Logic,and the Law

Chemistry is generally considered to be one of the exact sciences, which implies that much of the thinking and reasoning can be governed by “always” and “never” laws and rules. However, in practice, much of chemistry involves concepts that invoke general rules with the exceptions to those rules arousing curiosity and generating new experiments and theories that facilitate the progress of chemical science. The lack of precision, in fact, requires a mode of thinking and operating that has been called “fuzzy logic”, not necessarily in a pejorative sense, but rather recognizing the fundamental nature of this experimental science and how it plays out in practice. We provide herein some examples of fuzzy logic in the practice of chemistry and demonstrate how these are manifested in the role and behavior of expert witnesses, particularly in pharmaceutical patent litigations that deal with the solid forms of active pharmaceutical ingredients.