[Evaluation of Efficacy of Systemic Administration of Tranexamic Acid (Exacyl) in Total Hip and Knee Arthroplasty - Prospective Cohort Study]. / Hodnocení úcinnosti systémového podání tranexamové kyseliny (Exacylu) u náhrad kycelního a kolenního kloubu ­ prospektivní kohortová studie.

PURPOSE OF THE STUDY To evaluate the efficacy of the systemic administration of two doses of tranexamic acid (TXA) in total knee (TKA) and hip arthroplasty (THA). MATERIAL AND METHODS The study evaluated a total of 295 patients who underwent total knee and hip arthroplasty for osteoarthritis, prospectively followed up were the patients who had been administered the tranexamic acid (TXA), and this group was subsequently compared against the cohort - control group. Our evaluation was focused on perioperative and postoperative period. The amount of blood loss was monitored during the surgery as well as postoperatively. Moreover, the frequency and the volume of administered allogeneic blood transfusions and in TKA also autotransfusion requirement were observed. The patients postoperative hemoglobin levels were compared in both the groups when the patients were in the ICU and the frequency of all postoperative complications was monitored. The statistical analysis was carried out separately for hip and knee replacement. RESULTS Our study confirmed that the systemic application of tranexamic acid in two 10-15 mg/kg doses in knee arthroplasty resulted in a statistically significant reduction of perioperative and postoperative blood loss, lower frequency of administration of allogeneic blood transfusion, but also in lower frequency in the administration of any transfusion, including autotransfusion. In patients who underwent total hip arthroplasty, the administration of TXA led to a statistically significant reduction of postoperative bleeding. The patients with total knee as well as hip arthroplasty, who had been administered TXA, showed significantly higher haemoglobin levels when transferred from the ICU. No significant difference was found in deep vein thrombosis, pulmonary embolism or other postoperative complications among the study groups. DISCUSSION There is no homogeneity in the already published studies proving the efficacy of TXA in TKA and THA, they differ considerably as to the method of administration of the tranexamic acid. The differences concern the systemic and local application, dosage and time of administration. In some studies, TXA was administered in a single dose only, whereas in other studies it was administered repeatedly, in the form of a bolus or continuously. In our study we confirmed the efficacy of systemic administration of tranexamic acid in two repeated bolus doses of 10-15 mg/kg, namely before the commencement of the surgery and at the end of the surgery. CONCLUSIONS The administration of tranexamic acid in two IV doses of 10-15 mg/kg to patients with total knee and hip arthroplasty has proven to be efficient. A higher efficacy of TXA was reported in TKA and due to routine administration of TXA the postoperative autotransfusion system (ORTHO P.A.S.) ceased to be used in knee replacement surgery. Key words:total hip arthroplasty, total knee arthroplasty, tranexamic acid, blood loss, allogeneic transfusion, autotransfusion, postoperative complications.

Mechanical properties and microstructure of Ti-35.5Nb-5.7Ta beta alloy.

OBJECTIVE: Titanium and titanium alloys represent generally accepted metallic biomaterials for clinical dentistry and dental implantology. In this paper, we present a Ti-35.5Nb-5.7Ta alloy with a special respect to its microstructure and mechanical characteristics, such as Young modulus of elasticity. METHODS: Three thermal treatments differing in temperature and time of annealing were used during the Ti-35.5Nb-5.7Ta processing in order to evaluate the effects of ageing, melting annealing, and annealing on mechanical characteristics and microstructure. RESULTS: Using microscopy, the alloy was analyzed and the differences in shares of beta phase grains, alpha particles and precipitates evaluated. The three thermal treatments were evaluated also from technological point of view. CONCLUSION: The following thermal treatment was found optimal for the Ti-35.5Nb-5.7Ta alloy: melting annealing at 800 °C for 0.5 hour followed by a cold swaging with a 52-79 % deformation, and final hardening at 500 °C for 2 hours in water(Tab. 2, Fig. 3, Ref. 24).

Efficacy of the non-antibiotic paste Protexin Hoof-Care for topical treatment of digital dermatitis in dairy cows.

In this study, the efficacy of the non-antibiotic paste Protexin Hoof-Care containing metallic salts and organic acids, was tested for local treatment of 26 acute digital dermatitis lesions. The control group (26 cases) was treated with local application of oxytetracycline spray. These 52 affected limbs with digital dermatitis were diagnosed in 47 dairy cows from eight different farms with slatted floors. The therapeutic effect was evaluated using a scoring system for weightbearing at stance, lameness at walk and pain of the digital dermatitis lesions. The pre-treatment and control examination scores were documented on days 0, 4, 10 and 28. Both treatment regimens were effective, no statistical differences regarding the examined parameters was found between the group treated with the non-antibiotic Protexin Hoof-Care paste and the group treated with oxytetracycline spray. Twenty-seven digital dermatitis lesions required only one treatment with one of these products. A second topical treatment was carried out on day 4 in 13 lesions of the study group and in 12 lesions of the control group. The data of this pilot study indicate that the non-antibiotic paste Protexin Hoof-Care could be a valuable alternative to topical antibiotic treatment for digital dermatitis in dairy cattle.

Lateral division of the lateral posterior region: connections with area 18 in cats.

To establish the topography of the lateral division of the lateral posterior region (LP1) projections to area 18, up to five different anatomical tracers were injected in separate rostrocaudal locations in area 18 of four adult cats, and patterns of retrogradely labeled LP1 cells were identified. LP1 inputs to area 18 arose from both caudal and rostral nuclei and were topological, organized in patterns that indicate that lower visual space is represented anteroventrally, and more central and upper visual space is represented caudodorsally. In the caudal LP1 nucleus, patches of labeled cells formed bands that ran parallel to the medial and lateral LP1 borders and encompassed medial portions of the nucleus. In rostral LP1, the patches of labeled cells formed clusters giving the connections with area 18 a more modular appearance, and were nearer the lateral LP1 border. Injections made nearest area centralis representations in area 18 labeled more neurons than injections in cortex representing more peripheral visual space. Also, neighboring injections in area 18 labeled overlapping patches of cells, but no double-labeled cells were observed. These findings are consistent with previous conclusions based on electrophysiological mapping studies, that two retinotopically organized nuclei constitute LP1.

Central reorganization of sensory pathways following peripheral nerve regeneration in fetal monkeys.

Transection of a sensory nerve in adults results in profound abnormalities in sensory perception, even if the severed nerve is surgically repaired to facilitate accurate nerve regeneration. In marked contrast, fewer perceptual errors follow nerve transection and surgical repair in children. The basis for this superior recovery in children was unknown. Here we show that there is little or no topographic order in the median nerve to the hand after median nerve section and surgical repair in immature macaque monkeys. Remarkably, however, in the same animals the representation of the reinnervated hand in primary somatosensory cortex area (area 3b) is quite orderly. This indicates that there are mechanisms in the developing brain that can create cortical topography, despite disordered sensory inputs. Presumably the superior recovery of perceptual abilities after peripheral nerve transection in children depends on this restoration of somatotopy in the central sensory maps.

Topography, architecture, and connections of somatosensory cortex in opossums: evidence for five somatosensory areas.

Microelectrode maps of somatosensory inputs were related to cortical architecture and patterns of cortical connections to provide evidence for five subdivisions of the somatosensory or sensorimotor cortex in North American opossums (Didelphis marsupialis). Microelectrode recordings revealed three systematic representations of the body surface. A large mediolaterally oriented representation was identified as the primary somatosensory area (S1) by its relative position, somatotopy, architecture, and connections. S1 represented the hindlimb, trunk, forelimb, and face in a mediolateral sequence. Two additional representations of cutaneous receptors were found caudolateral to S1, each with face representations adjacent to the border of lateral S1 and other body-part representations progressing more caudally toward the auditory cortex. We identified the more dorsal field as the second somatosensory area (S2) and the more ventral field as the parietal ventral area (PV). Tracers injected into S1 labeled neurons and terminals in architectonically distinct fields rostral and caudal to S1, the somatosensory caudal area (SC) and the somatosensory rostral area (SR). Movements could be evoked by microstimulation from sites scattered over S1, SR, and the frontal cortex, but thresholds were high and uncharacteristic of motor cortex. S2 and PV merged caudally with the cortex responsive to auditory stimuli, possibly A1, and neurons in some caudal recording sites in PV were activated by both auditory and cutaneous stimuli. Primary (V1) and secondary (V2) visual areas were also identified by microelectrode mapping, architecture, and connections. In addition, at least part of the cortex between V2 and the somatosensory cortex had visual connections. Thus, most of the dorsolateral cortex of opossums appears to be somatosensory, auditory, or visual.

Surface-view connectivity patterns of area 18 in cats.

To determine surface-view connectivity patterns of area 18, separate injections of up to six anatomical tracers were delivered to various rostrocaudal locations of area 18 in six normal cats. Subsequently, cortex was separated from subcortical structures, manually flattened, and cut parallel to the surface. Results reveal that ipsilateral cortical connections of area 18 with three regions of cortex are topological. In areas 17 and 19, separate patches of cells labeled with different tracers progressed in a rostrocaudal sequence corresponding to the order of the injections. A similar but less precise pattern of rostrocaudal labeling occurred in more lateral visual cortex, even though several presumptive visual areas were involved. Thus, anteromedial suprasylvian cortex projected to anterior area 18 while more posterolateral suprasylvian cortex projected to posterior area 18. There was no evidence of double-labeled cells projecting to separate regions in area 18. These results are more consistent with the concept of a single suprasylvian area projecting to area 18 cortex than several.

The postnatal development of geniculocortical axon arbors in owl monkeys.

To characterize the postnatal development of geniculocortical axon arbor morphology in owl monkeys at a series of ages from birth to adulthood, individual arbors were bulk-filled with HRP in brain slice preparations and were reconstructed from serial sections. At all ages, cortical layers and sublayers were obvious. Presumed M or magnocellular arbors were largely confined to layer IV alpha, but they also extended into layer IIIc (IVB of Brodmann, 1909); presumed P or parvocellular arbors were almost exclusively confined to layer IV beta. Other axons that may reflect feedback projections from MT terminated in layer IIIc. Overall, M axon arbors increased in size and complexity from birth to adulthood with mean surface-view arbor areas ranging from 0.08 +/- 0.01 mm2 in newborns to 0.24 +/- 0.02 mm2 in adults. The developing P arbor areas were, on average, as large or larger than adult (newborn = 0.07 +/- 0.01 mm2, adult = 0.047 +/- 0.01 mm2; n.s.) but the arbors were somewhat less complex. Since the brain and area 17 increase in size postnatally, the proportion of area 17 subserved by each P arbor would decrease in postnatal development. Terminal boutons with immature features were evident in both M and P populations at all developmental ages. The results indicate that, while both LGN axon types in monkeys undergo morphological changes postnatally, M arbors appear to mature by increasing arbor size and terminal branching complexity, whereas P arbors increase in complexity but not in size. These distinct programs of axon arbor development suggest that the periods of susceptibility of geniculocortical axon arbors to postnatal influences of the environment, and the types of plastic responses they potentially exhibit, are class-specific.

Influence of daylength on male hamster sexual behavior: masking effects of testosterone.

Exposure of male hamsters to short photoperiods for 6-8 weeks cause deficits in sexual behavior with receptive females. The present experiment tested the hypothesis that short photoperiodic effects on behavior could be masked in the presence of chronic and stable levels of testosterone. Males were castrated and administered Silastic capsules of testosterone while housed in long (16L:8D) or short (8L:16D) photoperiodic conditions for 7 weeks. Sexual behavior tests at this time indicated that the short photoperiod males copulated less well, but group differences were not robust. Testosterone capsules were then removed and half the animals in both 16L:8D and 8L:16D were transferred to the opposite photoperiod. Sexual behavior was tested 18 days later as the effects of this functional castration developed. These tests indicate that photoperiodic effects were much more obvious in the absence of testosterone than they were during week 7 tests when testosterone was still present. The behavior of the males that were transferred from one photoperiod to the other demonstrated that exposure to the short photoperiod for only 18 days was not sufficient to generate short photoperiod-like sexual behavior deficits. In contrast, exposure to the long photoperiod for 18 days was sufficient to reverse short photoperiodic effects that had already developed.

Short photoperiods affect male hamster sociosexual behaviors in the presence and absence of testosterone.

Male hamsters were exposed to long (LD 14:10) or short (LD 8:16) photoperiods (LP; SP) to evaluate the effects of these environmental conditions on sociosexual behaviors. In Experiment 1, gonadally intact males in SP exhibited deficits in sexual behavior, reflected both in performance as well as initiation measures. Some aspects of the males' chemoinvestigation of females or their odors were also significantly different between LP and SP hamsters. In Experiment 2, castration resulted in the development of copulatory impairments, but they occurred more rapidly among males in SP conditions. Subsequent testosterone (T) replacement restored mounts, intromissions and ejaculations on tests given 2 and 4 weeks after T, but this happened more quickly in the LP group. SP males were still slower than LP males to initiate mounts and intromissions on their second test. These influences of photoperiod are discussed in the context of steroid-independent and steroid-dependent effects on behavior and the role of impaired processing of chemosensory information is evaluated.