Optimal effectiveness of BDNF for fetal nigral transplants coincides with the ontogenic appearance of BDNF in the striatum

Transplantation of fetal nigral dopamine neurons into the caudate and putamen of Parkinson's disease patients produces limited symptomatic relief. One approach to augment the outgrowth and function of nigral grafts includes exposure of the graphs to neurotrophic factors; however, the temporal requirements for optimizing these actions are unknown. The present study characterized the ontogeny of brain-derived neurotrophic factor (BDNF) in the rat striatum and used this information to define and evaluate three distinct periods of BDNF infusion into fetal nigral grafts transplanted into the striatum of rats with experimental Parkinson's disease. At postnatal day 1 (P1), BDNF and dopamine were measured at 17 and 27% of peak levels, respectively, that occurred at P27 for both. Both compounds showed their greatest surge between P7 and P20, increasing from 40% to approximately 95% of peak levels. Exogenous BDNF infused into transplants during weeks 1 and 2 after the transplantation, which coincide with the developmental period embryonic day 14 (E14)-P7 for transplanted tissue, did not improve rotational behavior or enhance fiber outgrowth of transplanted dopamine neurons. Delaying the BDNF infusion until transplanted tissue was approximately P8-P21 greatly enhanced the effect on rotational behavior and doubled the area of dopamine fiber outgrowth from the transplants. Delaying the infusion until transplanted tissue was approximately P36-P49 failed to augment fiber outgrowth and decreased the behavioral function of transplants. Thus, the optimal effect of exogenous BDNF on the development of dopamine neurons in fetal nigral transplants occurs at a postnatal age when endogenous dopamine and BDNF show the greatest increases during the normal development of the striatum.     

MRI scanning in suspected fractures of the scaphoid bone

MR examination was performed in 20 patients clinically suspected of having a fracture of the scaphoid bone. The patients also followed the normal routine with conventional radiographs in the acute fase and after 10-12 days. The MR was in most cases performed within a day after the trauma. All fractures seen on conventional radiographs were depicted on MR. MR further showed four fractures, five bone contusions (bone bruise) and lesions of the soft tissues in 75% of the patients. In patients with suspected fracture of the scaphoid, MR seems to be the best primary imaging method and displays a wide range of lesions.     

Differentiation of two strains of Mycoplasma gallisepticum with monoclonal antibodies and flow cytometry

Identification of infecting Mycoplasma spp. is difficult and not routine for strain. This paper describes a procedure for the rapid identification of the strain of M. gallisepticum. Monoclonal antibodies were prepared against M. gallisepticum F and M. gallisepticum S6. Aliquots of 24-hour broth cultures of these organisms were incubated briefly with either of the monoclonal antibodies. A second incubation was made with anti-mouse immunoglobulin conjugated to fluorescein isothiocyanate. Fluorescent intensity associated with the organisms was measured with a flow cytometer. The criterion for identification was a comparative increase in fluorescent intensity when the strain and monoclonal antibody were homologous. The procedure correctly differentiated the F and S6 strains of M. gallisepticum in a blind study.     

Manager Associate [IKBS]

The knowledge-based Manager Associate, which assists managers in planning, organizing, staffing, scheduling, measuring, visualizing, and controlling software development processes, is described. The Manager Associate operates in a distributed Unix environment in which the manager has access to the software developer workstations through a computer network. The Manager Associate helps managers anticipate problems, which allow early corrective action. As a result, software projects can be developed on time, within budget, and to customer satisfaction     

Capitated risk-bearing managed care systems could improve end-of-life care

A surface protein antigen (PAc) of Streptococcus mutans, in particular the A-region of this PAc molecule, has been noted as a possible target in research for an effective dental caries vaccine. To identify the antigenic peptide binding to major histocompatibility complex (MHC) class II (HLA-DR) molecules in the A-region, we prepared a panel of overlapping synthetic peptides in the second unit of the A-region, and established that a simple enzyme-linked immunosorbent assay (ELISA) binding assay could be achieved by incubating the DR-crude. Binding to DR molecules of these peptides from nine donors was investigated by using the ELISA binding assay. It was revealed that the PAc(316-334) peptide bound more strongly to the HLA-DR molecule in seven out of nine subjects. In particular, DR8 (DRB1*0802), DR5 (DRB1*1101) and DR6 (DRB1*1402 and *1405), which bound strongly to PAc(316-334) peptide, were identified. Moreover, we synthesized glycine-substituted peptide analogues of the peptide and examined the binding motif of the binding region. As a result, the multiple binding motif in DR8, DR5 and DR6 was found in L-RV-K-A. It is suggested that a peptide vaccine for dental caries that is more effective for humans, with fewer adverse side-effects, could be designed by combining the multiple binding motif with the B-cell epitope to produce only the inhibiting antibody against dental caries. The peptide could therefore be useful for peptide vaccine development in the general human population.     

Coenzyme A disulfide reductase, the primary low molecular weight disulfide reductase from Staphylococcus aureus. Purification and characterization of the native enzyme

The human pathogen Staphylococcus aureus does not utilize the glutathione thiol/disulfide redox system employed by eukaryotes and many bacteria. Instead, this organism produces CoA as its major low molecular weight thiol. We report the identification and purification of the disulfide reductase component of this thiol/disulfide redox system. Coenzyme A disulfide reductase (CoADR) catalyzes the specific reduction of CoA disulfide by NADPH. CoADR has a pH optimum of 7.5-8.0 and is a dimer of identical subunits of Mr 49,000 each. The visible absorbance spectrum is indicative of a flavoprotein with a lambdamax = 452 nm. The liberated flavin from thermally denatured enzyme was identified as flavin adenine dinucleotide. Steady-state kinetic analysis revealed that CoADR catalyzes the reduction of CoA disulfide by NADPH at pH 7.8 with a Km for NADPH of 2 muM and for CoA disulfide of 11 muM. In addition to CoA disulfide CoADR reduces 4,4'-diphosphopantethine but has no measurable ability to reduce oxidized glutathione, cystine, pantethine, or H2O2. CoADR demonstrates a sequential kinetic mechanism and employs a single active site cysteine residue that forms a stable mixed disulfide with CoA during catalysis. These data suggest that S. aureus employs a thiol/disulfide redox system based on CoA/CoA-disulfide and CoADR, an unorthodox new member of the pyridine nucleotide-disulfide reductase superfamily.     

InP/InGaAsP double-heterostructure optoelectronic switch

The double-heterostructure optoelectronic switch (DOES), fabricated in the InP/InGaAsP material system, is demonstrated. The functional characteristics and operational parameters exhibit a lower switching voltage (≈1.8 V) and a higher on-state holding current (≈20 mA) than found in either the Si/SiGe- or GaAs/AlGaAs-based DOES of comparable structures and doping levels. In the on-state, optical emission is observed in a manner analogous to a light emitting diode. However, enhanced optical emission is observed when the device is biased in the regime of negative differential resistance     

Extreme field-induced cyclotron mass variations in coupled double quantum wells

We observe deviations in the cyclotron effective mass m_c near the partial energy gap formed in strongly coupled GaAs double quantum wells (QWs) subject to in-plane magnetic fields B. In k-space, B shifts the two QW dispersion curves relative to one another, resulting in an anticrossing and opening the energy gap. This gives rise to large B-tunable distortions in the Fermi surface and density of states. This system is thus unique in that the Fermi surface and energy position of the gap can be controlled by sweeping B. Recently, Lyo has predicted that m_c undergoes large variations as the partial energy gap is moved through the Fermi level by B. By tilting our sample by a small angle θ, we introduce a small perpendicular magnetic field B, in addition to B, and analyze the temperature dependence of the resulting Shubnikov-de Haas oscillations to obtain m_c(B). Due to the strongly distorted dispersion near the gap, m_c is suppressed by more than a factor of 3 near the upper gap edge, and enhanced by 50% near the lower gap edge, in excellent agreement with the theory of Lyo. We also observe the quantum Hall effect in a double QW at a high, constant B.