Transduction of full-length TAT fusion proteins into mammalian cells: TAT-p27Kip1 induces cell migration

Human procathepsin L has been expressed in E. coli in the form of inclusion bodies. The recombinant protein was isolated, refolded and processed at pH 5.5 by the addition of dextran sulfate which increased the overall yield of cathepsin L almost 10-fold. After the auto-activation of the 38 kDa procathepsin L at least three processing sites were determined by N-terminal amino acid sequencing. After replacing the Ala205 residue by glutamic acid, cathepsin B-like specificity was introduced into cathepsin L. This mutation resulted in a 15-fold increased activity toward the substrate Z-Arg-Arg-AMC and in a 29-fold decreased activity toward Z-Phe-Arg-AMC. Residue 205 is thereby confirmed experimentally to be critical for the specificity of cathepsins B and L.     

Fourier transform Raman spectroscopy of polyacrylamide gels (PAGs) for radiation dosimetry

Polyacrylamide gels (PAGs) are used for magnetic resonance imaging radiation dosimetry. Fourier transform (FT) Raman spectroscopy studies were undertaken to investigate cross-linking changes during the copolymerization of polyacrylamide gels in the spectral range of 200-3500 cm(-1). Vibrational bands of 1285 cm(-1) and 1256 cm(-1) were assigned to acrylamide and bis-acrylamide single CH2 deltaCH2 binding modes. Bands were found to decrease in amplitude with increasing absorbed radiation dose as a result of copolymerization. Principal component regression was performed on FT-Raman spectra of PAG samples irradiated to 50 Gy. Two components were found to be sufficient to account for 98.7% of the variance in the data. Cross validation was used to establish the absorbed radiation dose of an unknown PAG sample from the FT-Raman spectra. The calculated correlation coefficient between measured and predictive samples was 0.997 with a standard error of estimate of 0.976 and a standard error of prediction of 1.140. Results demonstrate the potential of FT-Raman spectroscopy for ionizing radiation dosimetry using polyacrylamide gels.     

Causes of upper extremity compartment syndrome

Multiple causes, including various types of trauma, prolonged compression, muscle avulsions, burn, snake bites, high-pressure injection injuries, exercise, infection, bleeding, and intravenous drug infiltration, have been reported to lead to the development of a compartment syndrome in the upper extremity. Awareness of the different causes and risks of compartment syndrome should facilitate early diagnosis and prompt treatment to help avoid the development of serious sequelae such as Volkmann's ischemic contracture. A review of the various reports of upper extremity compartment syndromes and classification systems is presented to assist in the understanding of this condition's development.     

Evidence that bacteria prefer to adhere to thrombus

This study was undertaken to investigate the possible association between thrombosis and infection using an in vitro test model in which fresh bovine blood was recirculated through test conduits (3.5 mm inner diameter) containing stent-like devices. Anticoagulation was adjusted so that the recirculating blood deposited thrombi on the stent to cause gradual occlusion, thus impeding the flow. Four stent-like devices were placed in separate conduits in each experiment, and blood was recirculated with the help of pneumatically driven ventricles. Flow through these conduits was monitored by ultrasonic flow detection. To quantitate bacterial interaction with thrombi, Staphylococcus epidermidis (15E10(9)) was labeled with 111Indium-oxine and added to the blood. Experiments lasted until the flow in the test conduits dropped to 10% of the starting flow. During this recirculation, as flow gradually decreased, one stent was taken out when flow was still at 100%, the second at 75%, the third at 50%, and the fourth at 10% of the starting flow. The number of bacteria associated with the thrombus was measured by gamma counting. The following observations were made: 1) the amount of thrombus increased with time in all experiments (this was confirmed in separate experiments by using autologous 111Indium labeled platelets); 2) bacterial adhesion showed a concomitant increase as thrombus size increased (this was confirmed by using 111Indium labeled bacteria), and 3) bacterial incorporation into the thrombus occurred regardless of whether they were viable or pretreated with the antibiotic rifampin. These observations suggest that as thrombi develop, they may preferentially attract micro-organisms. This suggests that devices with adherent thrombi may have greater susceptibility for infection.     

Par-4 is a mediator of neuronal degeneration associated with the pathogenesis of Alzheimer disease

Prostate apoptosis response-4 (Par-4) is a protein containing both a leucine zipper and a death domain that was isolated by differential screening for genes upregulated in prostate cancer cells undergoing apoptosis. Par-4 is expressed in the nervous system, where its function is unknown. In Alzheimer disease (AD), neurons may die by apoptosis, and amyloid beta-protein (A beta) may play a role in this. We report here that Par-4 expression is increased in vulnerable neurons in AD brain and is induced in cultured neurons undergoing apoptosis. Blockade of Par-4 expression or function prevented neuronal apoptosis induced by Ab and trophic factor withdrawal. Par-4 expression was enhanced, and mitochondrial dysfunction and apoptosis exacerbated, in cells expressing presenilin-1 mutations associated with early-onset inherited AD.     

Enantioselective determination of oxprenolol and its metabolites in human urine by cyclodextrin-modified capillary zone electrophoresis

A stereospecific capillary electrophoresis assay for oxprenolol enantiomers and their basic metabolites in human urine has been developed using hydroxypropyl-beta-CD as a chiral selector in the mobile phase. The bioassay method has been validated and the detection limit from spiked urine samples is 0.2 micrograms/ml. The calibration curves are linear from 0.4 to 16 micrograms/ml. Extraction recovery ranged from 84.7 to 96.4% for all the compounds studied. The influence of various parameters on the chiral separation of oxprenolol and its basic metabolites have been investigated. Urinary excretion profiles of oxprenolol enantiomers and those of two metabolites have also been studied, following a single oral dose of racemic oxprenolol.     

CT features of calcifications in abdominal malignant fibrous histiocytoma

Driven by the need for a readily available, non-immunological tissue that possesses many of the characteristics of normal human skin, tissue-engineered skin has been developed. For over a decade, laboratory grown or processed skin has been under investigation and, in some cases, available as an alternative to autologous grafts. Apligraf, derived from neonatal foreskin and bovine type I collagen, is the first bi-layered living skin equivalent approved in the US and other countries for use in venous ulcers. Apligraf is effective both in the treatment of refractory venous ulcers and for acute wounds such as surgical excision sites and split thickness donor sites. Apligraf is safe and is not clinically rejected. Its ultimate fate is not known, so it may well work to aid healing in a variety of ways including graft 'take' and as a stimulus for healing.