A clinical method to determine the effectiveness of dental handpiece sterilization

The interaction of ventilation and hemodynamics in the posttraumatic period has been studied in 131 patients with severe craniocerebral trauma. Indexes of respiratory function, central and pulmonary hemodynamics were determined over the first week and on days 10, 14, 21 and 28 after trauma. The data obtained have shown that respiratory function and circulation damages during brain trauma are predetermined by the reduction in pulmonary volume and capacity, impaired alveolar ventilation and bronchial patency, followed by development of atelectasis of the lungs and pulmonary shunt. Patients with severe brain injury more often develop bronchospasm and disorders of central and pulmonary hemodynamics, as compared to patients with moderate injury.     

Risedronate in the treatment of Paget's disease of bone: an open label, multicenter study

An open-label, multicenter study was conducted to determine the efficacy and safety of oral risedronate (a pyridinyl bisphosphonate) in 162 patients (102 men, 60 postmenopausal women; mean age, 68 years) with moderate to severe Paget's disease of bone (mean serum alkaline phosphatase [ALP] approximately seven times the upper limit of normal). Patients were treated with oral risedronate, 30 mg/day for 84 days, followed by 112 days without treatment. This 196-day cycle was repeated once if serum ALP did not normalize or increased from the nadir value by > or = 25%. At the end of the first and second cycles, the mean percentage decreases for serum ALP were 65.7% and 69.1%, and for urinary hydroxyproline/creatinine 50.4% and 66.9%, respectively. The decreases from baseline in ALP and urinary hydroxyproline/creatinine were significant (p < 0.001). Normalization of serum ALP was observed in 86 patients (53.8%): 53 during the first treatment cycle and 33 during the second. There was a significant proportion of patients reporting a decrease in the pagetic bone pain at days 84 and 196 (p < 0.001). Overall, risedronate was well tolerated. Five patients withdrew due to adverse events, none of which were considered to be drug related. In conclusion, 30 mg of oral risedronate administered daily for 84 days significantly reduced the biochemical indices of disease activity and was associated with pain reduction in patients with moderate to severe Paget's disease of bone. Normalization of ALP was observed in the majority of patients. Repeated administration of risedronate was shown to be beneficial. In general, risedronate was well tolerated and demonstrated a good safety profile.     

Chondrocyte apoptosis and nitric oxide production during experimentally induced osteoarthritis

OBJECTIVE: Chondrocytes produce nitric oxide (NO) and undergo apoptosis in response to exogenous NO. This study sought to examine the relationship between NO synthesis, chondrocyte apoptosis, and the development of cartilage degradation during experimental osteoarthritis (OA). METHODS: OA was induced in rabbits by anterior cruciate ligament transection (ACLT). Knees were harvested after 4 weeks and assessed for OA severity and chondrocyte apoptosis. Conditioned media from cultured cartilage explants were analyzed for nitrite content. Cartilage sections were analyzed by immunohistochemistry for the presence of nitrotyrosine. RESULTS: All ACLT knees demonstrated osteoarthritic changes. Conditioned media from ACLT cartilage organ cultures contained higher levels of nitrite as compared with cartilage samples from the nonoperated side or from rabbits that had not received ACLT. Cultures of specific areas of cartilage from ACLT knees showed high levels of NO production in the medial femoral and medial tibial cartilage. Approximately 28.7% of chondrocytes isolated from ACLT cartilage and 6.7% of chondrocytes from cartilage of the nonoperated side underwent apoptosis. In situ staining demonstrated apoptotic cells in the superficial and middle zones of ACLT cartilage. A high number of apoptotic cells was present at the pannus-cartilage junction. In control cartilage, the superficial zone contained a small number of cells in apoptosis. The prevalence of apoptotic cells was significantly correlated with the levels of nitrite production and OA grade. CONCLUSION: These observations suggest that, during the early phases of OA, NO production may lead to chondrocyte apoptosis, and that both events contribute to the pathogenesis of cartilage degradation. Inhibitors of NO synthesis and chondrocyte apoptosis may therefore be of therapeutic value after cartilage injury and in patients with OA.     

A developmentally regulated kinesin-related motor protein from Dictyostelium discoideum

The cellular slime mold Dictyostelium discoideum is an attractive system for studying the roles of microtubule-based motility in cell development and differentiation. In this work, we report the first molecular characterization of kinesin-related proteins (KRPs) in Dictyostelium. A PCR-based strategy was used to isolate DNA fragments encoding six KRPs, several of which are induced during the developmental program that is initiated by starvation. The complete sequence of one such developmentally regulated KRP (designated K7) was determined and found to be a novel member of the kinesin superfamily. The motor domain of K7 is most similar to that of conventional kinesin, but unlike conventional kinesin, K7 is not predicted to have an extensive alpha-helical coiled-coil domain. The nonmotor domain is unusual and is rich in Asn, Gln, and Thr residues; similar sequences are found in other developmentally regulated genes in Dictyostelium. K7, expressed in Escherichia coli, supports plus end-directed microtubule motility in vitro at a speed of 0.14 micron/s, indicating that it is a bona fide motor protein. The K7 motor is found only in developing cells and reaches a peak level of expression between 12 and 16 h after starvation. By immunofluorescence microscopy, K7 localizes to a membranous perinuclear structure. To examine K7 function, we prepared a null cell line but found that these cells show no gross developmental abnormalities. However, when cultivated in the presence of wild-type cells, the K7-null cells are mostly absent from the prestalk zone of the slug. This result suggests that in a population composed largely of wild-type cells, the absence of the K7 motor protein interferes either with the ability of the cells to localize to the prestalk zone or to differentiate into prestalk cells.     

Two proteins of the Dictyostelium spore coat bind to cellulose in vitro

The spore coat of Dictyostelium contains nine different proteins and cellulose. Interactions between protein and cellulose were investigated using an in vitro binding assay. Proteins extracted from coats with urea and 2-mercaptoethanol could, after removal of urea by gel filtration, efficiently bind to particles of cellulose (Avicel), but not Sephadex or Sepharose. Two proteins, SP85 and SP35, were enriched in the reconstitution, and they retained their cellulose binding activities after purification by ion exchange chromatography under denaturing conditions to suppress protein--protein interactions. Neither protein exhibited cellulase activity, though under certain conditions SP85 copurified with a cellulase activity which appeared after germination. Amino acid sequencing indicated that SP85 and SP35 are encoded by the previously described pspB and psvA genes. This was confirmed for SP85 by showing that natural M(r) polymorphisms correlated with changes in the number of tetrapeptide-encoding sequence repeats in pspB. Using PCR to reconstruct missing elements from the recombinogenic middle region of pspB, SP85 was shown to consist of three sequence domains separated by two groups of the tetrapeptide repeats. Expression of partial pspB cDNAs in Escherichia coli showed that cellulose-binding activity resided in the Cys-rich COOH-terminal domain of SP85. This cellulose-binding activity can explain SP85's ultrastructural colocalization with cellulose in vivo. Amino acid composition and antibody binding data showed that SP35 is derived from the Cys-rich N-terminal region of the previously described psvA protein. SP85 and SP35 may link other proteins to cellulose during coat assembly and germination.     

Development of a time-resolved soft x-ray spectrometer for laser produced plasma experiments

A 2400 lines/mm variable-spaced grating spectrometer has been used to measure soft x-ray emission (8-22 A?) from laser-produced plasma experiments at Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) Laser Facility. The spectrometer was coupled to a Kentech x-ray streak camera to study the temporal evolution of soft x rays emitted from the back of the Mylar and the copper foils irradiated at 10(15)?W/cm(2). The instrument demonstrated a resolving power of ～120 at 19 A? with a time resolution of 31 ps. The time-resolved copper emission spectrum was consistent with a photodiode monitoring the laser temporal pulse shape and indicated that the soft x-ray emission follows the laser heating of the target. The time and spectral resolutions of this diagnostic make it useful for studies of high temperature plasmas.     

An objective approach to antivenom therapy and assessment of first-aid measures in snake bite

Treatment of systemic envenoming in snake-bite victims has, in the past, depended almost entirely on the individual clinician's experience in assessing the severity of envenoming. The efficacy of treatment is obviously related to the neutralizing potency of the antivenom used, the route by which it is administered and the dose. The development of enzyme immunoassays has permitted a more scientific appraisal, allowing estimation of circulating specific venom and antivenom concentrations at any time after the bite in the patient's blood. It is therefore possible to measure accurately the efficacy of antivenom in the neutralization and clearance of venom antigen. In Brazil, it appears that clinicians treat patients with excessive amounts of highly efficient antivenoms and this results in an unacceptably high incidence of reactions. In Sri Lanka, the use of imported, Indian antivenom is relatively ineffective in neutralizing the venoms of Sri Lankan snakes, demonstrating the real problem of venom variability within individual species. In West Africa, the improved clearance of venom following treatment of Echis victims with a monospecific as opposed to a polyspecific antivenom has been demonstrated, and new, smaller fragment, Fab antivenoms have been developed and are now under clinical assessment. Such clinically-based immunological studies should result in more efficient and controlled use of expensive antivenoms for treatment of systemic envenoming and the accurate assessment of newly designed products. Such studies also emphasise the importance of individual countries producing their own antivenoms for treatment of systemic envenoming. Likewise, the use of such objective systems now enables the use of first-aid measures such as tourniquets to be properly assessed.