Gene therapy with HSP72 is neuroprotective in rat models of stroke and epilepsy

Brain areas damaged by stroke and seizures express high levels of the 72-kd heat shock protein (HSP72). Whether HSP72 represents merely a marker of stress or plays a role in improving neuron survival in these cases has been debated. Some induced tolerance experiments have provided correlative evidence for a neuroprotective effect, and others have documented neuroprotection in the absence of HSP72 synthesis. We report that gene transfer therapy with defective herpes simplex virus vectors overexpressing hsp72 improves neuron survival against focal cerebral ischemia and systemic kainic acid administration. HSP72 overexpression improved striatal neuron survival from 62.3 to 95.4% in rats subjected to 1 hour of middle cerebral artery occlusion, and improved survival of hippocampal dentate gyrus neurons after systemic kainic acid administration, from 21.9 to 64.4%. We conclude that HSP72 may participate in processes that enhance neuron survival during transient focal cerebral ischemia and excitotoxin-induced seizures.     

Calcium-induced bilirubin-dependent hemolysis of human erythrocytes

ADP-glucose pyrophosphorylase from photosynthetic tissue is allosterically regulated by 3-phosphoglycerate and inorganic phosphate. In contrast, data from our laboratory indicated that the major AGPase from barley seeds is insensitive to these regulators. Verification of this conclusion has, however, been hindered by the proteolytic degradation of the enzyme from seeds. This report characterizes the barley seed AGPase expressed in the baculovirus-insect cell system, confirming that lack of allosteric regulation by 3-PGA/Pi is an intrinsic property of the enzyme. Purification of the enzyme was by Ni2+-NTA agarose chromatography using a (His)6 tag attached to the N-terminus of the small AGPase subunit.     

Defining and measuring unintended pregnancy: issues and concerns

PURPOSE: The authors describe a proactive model of psychosocial care for patients undergoing blood or marrow transplantation and their families. DESCRIPTION OF PROGRAM: This program for blood or marrow transplantation patients, developed at the Center for Cancer Treatment and Research, Richland Memorial Hospital, and the University of South Carolina School of Medicine in Columbia, South Carolina, involves pretransplant comprehensive psychosocial assessment; development and implementation of an individual psychosocial treatment plan; monitoring and medical management of neuropsychiatric problems; and psychotherapeutic sessions with a psychiatrist. These functions are achieved through the use of a multidisciplinary psychosocial team and ongoing consultation-liaison with the entire blood or marrow transplantation team. CLINICAL IMPLICATIONS: This positive, proactive model demonstrates significant benefit to patients, families, and the blood or marrow transplantation healthcare team. Benefits of this model are derived from psychosocial assessment during work-up, subsequent planning, and communication with the entire team, thus allowing early identification of problems and avoiding escalation and the likelihood of negative outcomes. Less energy is exerted and less resources expended when problems are resolved with early intervention rather than with intensive interventions during transplant. The psychosocial staff members develop strong relationships with patients and families before transplant, increasing the power of interventions and receptivity of the patient. The blood or marrow transplantation team benefits from the ongoing presence of psychosocial staff and the consistency of approaches offered by team members. An integral part of this approach is teaching psychosocial care to all staff members and modeling approaches to problems. Other blood or marrow transplantation centers and centers providing other intensive anticancer therapies may benefit by adapting this model into the day-to-day care of their patients.     

ON THE EQUIVALENCE OF STRESS INTENSITY AND ENERGY APPROACHES IN BRIDGING ANALYSIS

Abstract— Through-thickness reinforcement is effective in suppressing delamination in composite laminates. It provides bridging in the crack wake during delamination crack growth. The closure traction behind the crack tip due to this bridging increases the delamination toughness significantly. The effect of bridging may be analysed using the stress intensity approach or the Griffith energetic approach. In this paper, delamination crack growth resistance K _R,(Δa) of a double-cantilever-beam specimen, with through-thickness reinforcement, under Mode I delamination is determined using these two approaches. Additionally, the J-integral analysis is also employed. A comparison between the theoretical results predicted by these three methods is provided using the example of stitched CFRP.     

CFTR: the nucleotide binding folds regulate the accessibility and stability of the activated state

The functional roles of the two nucleotide binding folds, NBF1 and NBF2, in the activation of the cystic fibrosis transmembrane conductance regulator (CFTR) were investigated by measuring the rates of activation and deactivation of CFTR Cl- conductance in Xenopus oocytes. Activation of wild-type CFTR in response to application of forskolin and 3-isobutyl-1-methylxanthine (IBMX) was described by a single exponential. Deactivation after washout of the cocktail consisted of two phases: an initial slow phase, described by a latency, and an exponential decline. Rate analysis of CFTR variants bearing analogous mutations in NBF1 and NBF2 permitted us to characterize amino acid substitutions according to their effects on the accessibility and stability of the active state. Access to the active state was very sensitive to substitutions for the invariant glycine (G551) in NBF1, where mutations to alanine (A), serine (S), or aspartic acid (D) reduced the apparent on rate by more than tenfold. The analogous substitutions in NBF2 (G1349) also reduced the on rate, by twofold to 10-fold, but substantially destabilized the active state as well, as judged by increased deactivation rates. In the putative ATP-binding pocket of either NBF, substitution of alanine, glutamine (Q), or arginine (R) for the invariant lysine (K464 or K1250) reduced the on rate similarly, by two- to fourfold. In contrast, these analogous substitutions produced opposite effects on the deactivation rate. NBF1 mutations destabilized the active state, whereas the analogous substitutions in NBF2 stabilized the active state such that activation was prolonged compared with that seen with wild-type CFTR. Substitution of asparagine (N) for a highly conserved aspartic acid (D572) in the ATP-binding pocket of NBF1 dramatically slowed the on rate and destabilized the active state. In contrast, the analogous substitution in NBF2 (D1370N) did not appreciably affect the on rate and markedly stabilized the active state. These results are consistent with a hypothesis for CFTR activation that invokes the binding and hydrolysis of ATP at NBF1 as a crucial step in activation, while at NBF2, ATP binding enhances access to the active state, but the rate of ATP hydrolysis controls the duration of the active state. The relatively slow time courses for activation and deactivation suggest that slow processes modulate ATP-dependent gating.