Effects of medium viscosity on kinetics of the enzymatic reaction catalyzed by bacterial RNase

Effects of medium viscosity on kinetic parameters of poly(U) hydrolysis catalyzed by RNase from Bac. intermedius 7P (binase) were studied in solutions of sucrose (4-50 wt. %) and glycerol (35-62 wt. %) in Tris--sodium acetate buffer (pH 7.5) at 25 degreesC. The rate constant of reaction kcat was practically unchanged over a wide range of viscosities (1-15 cP for sucrose and 2.5-3 cP for glycerol). In glycerol solutions, kcat slightly increased with viscosity increase from 4 to 10 cP. Addition of NaCl to the buffer medium resulted in an inhibitory effect of Na+ on kcat, prevented by 50% sucrose or 60% glycerol. It is concluded that binase-catalyzed poly(U) cleavage occurs through a "tense"-substrate mechanism, similarly to reactions catalyzed by alpha-chymotrypsin, trypsin, and laccase.     

Healing of "wire tunnels" in tibial diaphysis: data of local X-ray study and densitometry

Fifteen pelvic extremities from adult dogs were used to perform 60 cross tunnelization of tibial diaphysis with a wire having a pointed groove, 1.8-mm in diameter, at 1,500 rpm. Thirty five leg X-ray films in the lateral projection, which show changes on days 30, 60, 90, 120, 520 after the experiment, were studied. Bony diaphysis tunnelization was found to give rise to a regeneration focus wherein an area of tissue element degradation and an area of introduction of bony fragments into soft tissues were detectable. Changes in the regeneration focus were determined by a response to osseous fragments, which involved the formation of an bony regenerate during a month and to the resorption of the bony matter of an osseous regenerate and osseous fragments in future. Healing of diaphysis defects began with the resorption of a damaged cortical layer. Osteogenesis prevailed at month 2 and ensured healing of cortical layer defects following 4-6 months.     

Hatching asynchrony and brood reduction influence immune response in Common Kestrel Falco tinnunculus nestlings

The onset of incubation before the end of laying imposes asynchrony at hatching and, therefore, a size hierarchy in the brood. It has been argued that hatching asynchrony might be a strategy to improve reproductive output in terms of quality or quantity of offspring. However, little is known about the mediating effect of hatching asynchrony on offspring quality when brood reduction occurs. Here, we investigate the relationship between phenotypic quality and hatching asynchrony in Common Kestrel Falco tinnunculus nestlings in Spain. Hatching asynchrony did not increase breeding success or nestling quality. Furthermore, hatching asynchrony and brood reduction had different effects on nestlings’ phytohaematogglutinin (PHA)‐mediated immune response and nestling growth. In asynchronous and reduced broods (in which at least one nestling died), nestlings showed a stronger PHA‐mediated immune response and tended to have a smaller body size compared with nestlings raised in synchronous and reduced broods. When brood reduction occurred in broods hatched synchronously, there was no effect on nestling size, but nestlings had a relatively poor PHA‐mediated immune response compared with nestlings raised in asynchronous and reduced broods. We suggest that resources for growth can be directed to immune function only in asynchronously hatched broods, resulting in improved nestling quality, as suggested by their immune response. We also found that males produced a greater PHA‐mediated immune response than females only in brood‐reduced nests without any effect on nestling size or condition, suggesting that females may trade off immune activities and body condition, size or weight. Overall, our results suggest that hatching pattern and brood reduction may mediate resource allocation to different fitness traits. They also highlight that the resolution of immune‐related trade‐offs when brood reduction occurs may differ between male and female nestlings.     

Micropropagation of the endangered species Malus niedzwetzkyana for conservation biodiversity in Kazakhstan

In Vitro Cellular & Developmental Biology - Plant - Biodiversity conservation requires advanced and effective ex situ plant propagation techniques. The present study was conducted to optimize...     

Severe Painful Vaso-Occlusive Crises and Mortality in a Contemporary Adult Sickle Cell Anemia Cohort Study

Background

Frequent painful vaso-occlusive crises (VOCs) were associated with mortality in the Cooperative Study of Sickle Cell Disease (CSSCD) over twenty years ago. Modern therapies for sickle cell anemia (SCA) like hydroxyurea are believed to have improved overall patient survival. The current study sought to determine the relevance of the association between more frequent VOCs and death and its relative impact upon overall mortality compared to other known risk factors in a contemporary adult SCA cohort.

Methods

Two hundred sixty four SCA adults were assigned into two groups based on patient reported outcomes for emergency department (ED) visits or hospitalizations for painful VOC treatment during the 12 months prior to evaluation.

Results

Higher baseline hematocrit (p = 0.0008), ferritin (p = 0.005), and HDL cholesterol (p = 0.01) were independently associated with 1 or more painful VOCs requiring an ED visit or hospitalization for acute pain. During a median follow-up of 5 years, mortality was higher in the ED visit/hospitalization group (relative risk [RR] 2.68, 95% CI 1.1-6.5, p = 0.03). Higher tricuspid regurgitatant jet velocity (TRV) (RR 2.41, 95% CI 1.5-3.9, p < 0.0001), elevated ferritin (RR 4.00, 95% CI 1.8-9.0, p = 0.001) and lower glomerular filtration rate (RR=2.73, 95% CI 1.6-4.6, p < 0.0001) were also independent risk factors for mortality.

Conclusions

Severe painful VOCs remain a marker for SCA disease severity and premature mortality in a modern cohort along with other known risk factors for death including high TRV, high ferritin and lower renal function. The number of patient reported pain crises requiring healthcare utilization is an easily obtained outcome that could help to identify high risk patients for disease modifying therapies.

Trial Registration

ClinicalTrials.gov NCT00011648 http://clinicaltrials.gov/     

Description of rearrangement of distraction reclaim in the extension of the lower extremities and elimination of their deformity in patients with various etiology of shortening

The data of X-ray and computed tomographic studies of a long tube distraction reclaim were analyzed in 80 patients who had limb shortening and deformity of varying etiology. The analysis has shown that during distraction there is a positive correlation between the increase in the connective-tissue interlayer area of a distraction reclaim and the overall increase in the area of the distraction reclaim (their ratio is not greater than 30% under the optimal elongation conditions). During fixation there is a decrease in the ratio of the area of a growth zone to the total area of a reclaim and in its total density with a parallel increase in the density of cortical laminae of a newly formed bone. Complete organotypic rearrangement comes to the end in the range of 1-3 years depending on the magnitude of pathomorphological and biomechanical changes and limb function.     

Changes in hemodynamics of the long bone due to tunnelization under pulsing and non-pulsing pressure in a shaft cavity

In 25 dogs, it was revealed that the pressure in a long bone shaft cavity (IBP) pulsed at relatively high values. According to rheovasography data, the pulse changes of the vascular blood filling of a shaft cavity caused the IBP. The blood filling changes at pulsing IBP produced pulse changes in interstitial fluid amount, at non-pulsing IBP they provided for fluid coming into the interstitial space of the shaft cavity without pulsations. Tunnelization led to appearance of compact substance defect, at the size of which, coming to 2.4% of shaft area, IBP always decreased, remained decreased during 2 months and restored during the third month. The IBP decrease changed the bone hemodynamics.