Circadian phase and intertrial interval interfere with social recognition memory

A modified version of the social habituation/dis-habituation paradigm was employed to examine social recognition memory in Wistar rats during two opposing (active and inactive) circadian phases, using different intertrial intervals (30 and 60 min). Wheel-running activity was monitored continuously to identify circadian phase. To avoid possible masking effects of the light-dark cycle, the rats were synchronized to a skeleton photoperiod, which allowed testing during different circadian phases under identical lighting conditions. In each trial, an infantile intruder was introduced into an adult's home-cage for a 5-minute interaction session, and social behaviors were registered. Rats were exposed to 5 trials per day for 4 consecutive days: on days 1 and 2, each resident was exposed to the same intruder; on days 3 and 4, each resident was exposed to a different intruder in each trial. The resident's social investigatory behavior was more intense when different intruders were presented compared to repeated presentation of the same intruder, suggesting social recognition memory. This effect was stronger when the rats were tested during the inactive phase and when the intertrial interval was 60 min. These findings suggest that social recognition memory, as evaluated in this modified habituation/dis-habituation paradigm, is influenced by the circadian rhythm phase during which testing is performed, and by intertrial interval.     

Evaluation of surface characteristics of Ti-6Al-4V and Tilite alloys used for implant abutments

The aim of this study was to evaluate surface free energy (SFE), surface roughness (SR) and surface hardness (SH) of two commercially available materials for fabricating dental implant abutments. In addition, the specimens were investigated by scanning electron microscopy (SEM) to determine the surface morphology. Twenty five discs (5 x 2 mm) of Ti-6Al-4V and Tilite (Ni-Cr-Ti) alloys were used in this study. Surface free energy was determined by the contact angle formed between a drop of distilled, deionized water and the surface of the specimen of each material. The surface roughness was measured with a mechanical profilometer and the surface hardness was evaluated by means of the Vickers hardness micro indentation test. SFE, SR and SH data were analyzed using one-way ANOVA (p < 0.05). Statistical differences (p < 0.05) were found between Ti-6Al-4V (36.2 erg x cm(-2); 0.2 microm) and Tilite (30.9 erg x cm(-2); 0.16 microm) for SFE and SR. However, the differences between the surface hardness values of Ti-6Al-4V (325.0 kg/mm(2)) and Tilite (324.3 kg/mm(2)) were not statistically significant (p > 0.05). Evaluations by SEM revealed different surface morphology. Within the limits of this study, it can be concluded that the Ti-6Al-4V and Tilite alloys showed differences in surface properties, except for surface hardness, suggesting that both alloys may be considered appropriate for producing abutments. Further studies are, however, necessary to elucidate the biological responses to implant abutments made with these alloys.     

Influence of toothbrushing on enamel softening and abrasive wear of eroded bovine enamel: an in situ study

This study assessed the surface softening and abrasive wear of eroded bovine enamel with or without the influence of toothbrushing. Five volunteers took part in this in situ study of 5 days. They wore acrylic palatal appliances containing 6 bovine enamel blocks divided in two rows with 3 blocks, which corresponded to the studied groups: erosion without toothbrushing (GI) and erosion with toothbrushing (GII). The blocks were subjected to erosion by immersion of the appliances in a cola drink for 10 minutes, 4 times a day. After that, no treatment was performed in one row (GI), whereas the other row was brushed (GII). The appliance was then replaced into the mouth. Enamel alterations were determined using profilometry and microhardness tests. Data were tested using paired Students t test (p < 0.05). The mean wear values (microm) and percentage of superficial microhardness change (%SMHC) were respectively: GI--2.77 +/- 1.21/91.61 +/- 3.68 and GII--3.80 +/- 0.91/58.77 +/- 11.47. There was a significant difference in wear (p = 0.001) and %SMHC (p = 0.001) between the groups. It was concluded that the wear was more pronounced when associated to toothbrushing abrasion. However, toothbrushing promoted less %SMHC due to the removal of the altered superficial enamel layer.     

An ethnomedicinal survey on phytotherapy with professionals and patients from Basic Care Units in the Brazilian Unified Health System

Ethnopharmacological relevance

In this study, an ethnomedicinal survey was conducted in the city of Pelotas, Brazil, with professionals and patients in the Unified Health System (SUS). With the approval of the National Policy on Medicinal Plants and Herbal Medicines, and with the adoption of a National Policy on Integrative and Complementary Practices in the SUS in Brazil, there is growing concern regarding Brazilian medicinal plants and their proper use in medicine. The expansion of the therapeutic options offered to the users of the SUS includes access to medicinal plants and herbal drugs, as well as related services, such as phytotherapy. For improving health and for the social inclusion of phytotherapies, safety, efficacy, and quality are important strategies.

Materials and methods

Interviews of both professionals and patients were conducted at five Basic Care Units, and a sample size of 393 was obtained.

Results

Of the patients attending the Basic Care Units, 91.6% had experienced the use of medicinal plants at least once to treat certain diseases. Of the professionals, 65% had used medicinal plants but only 10% prescribed phytotherapeutics to their patients. Generally, the users were homemakers (26%) of the female gender (71.5%) who were older than 60 years (26%) and had a family income between 1 and 2 Brazilian minimal salaries. The professionals were predominantly female (80%), and a high proportion (80%) believed in the positive effects of phytotherapy (80%), even though these professionals had not been taught phytotherapy as undergraduate students (75%) and had not discussed the topic with their teachers (85%). Patients (81.5%) and professionals (45%) reported that their knowledge of medicinal plants came from their parents or grandparents. From a total of 66 different herbs used by the subjects, mauve (24%) was the most commonly used, often to treat toothaches (24.2%).

Conclusion

It is concluded that a high proportion of users and professionals made use of medicinal plants, and of the large number of plants mentioned in the questionnaire, mauve was the most commonly used, mainly for the treatment of toothaches. The major source of the transmission of knowledge concerning herbal medicine was parents or grandparents.     

血管紧张素受体抑制剂：可降低老年痴呆发病率

本研究的目的是探讨血管紧张素受体抑制剂能否预防阿尔茨海默病和痴呆,或者减缓这两种疾病的病情进展。     

The role of canonical WNT signaling pathway in oral carcinogenesis: a comprehensive review

Oral cancer is a common neoplasm worldwide. The incidence and mortality have also increased in recent decades. It is characterized by poor prognosis and a low survival rate despite sophisticated surgical and radiotherapeutic modalities. The WNTs comprise a large family of highly conserved growth factors associated with a number of functions. In this review, we focus largely on the canonical pathway, revealing the recent findings, in oral cancer research, thereby raising our understanding of the mechanisms of this crucial signaling in several cellular activities.     

Bone marrow stromal cells and resorbable collagen guidance tubes enhance sciatic nerve regeneration in mice

We evaluated peripheral nerve regeneration using a tubular nerve guide of resorbable collagen filled with either bone marrow-derived cells (BMDCs) in Dulbecco's cell culture medium (DMEM) or with DMEM alone (control). The control group received just the culture medium (vehicle). The left sciatic nerves of ten isogenic mice were transected and the tubular nerve guides were sutured to the end of the proximal and distal nerve stumps. Motor function was tested at 2, 4 and 6 weeks after surgery using the walking track test. The pawprints were analyzed and the print lengths (PL) were measured to evaluate functional recovery. After 6 weeks, mice were anesthetized, perfused transcardially with fixative containing aldehydes, and the sciatic nerves and tubes were dissected and processed for scanning and transmission electron microscopy. Scanning electron microscopy of the collagen tube revealed that the tube wall became progressively thinner after surgery, proving that the tube can be resorbed in vivo. Quantitative analysis of the regenerating nerves showed that the number of myelinated fibers and the myelin area were significantly increased in the experimental group. Also, motor function recovery was faster in animals that received the cell grafts. These results indicate that the collagen tube filled with BMDCs provided an adequate and favorable environment for the growth and myelination of regenerating axons compared to the collagen tube alone.     

A cost analysis of the treatment of patients with post-thrombotic syndrome in Brazil

INTRODUCTION: Post-thrombotic syndrome (PTS) occurs in 15-50% of patients with deep vein thrombosis (DVT), and is associated with substantial medical costs. This prospective observational study investigated the costs associated with the treatment of PTS in Brazil. MATERIALS AND METHODS: A total of 157 patients diagnosed with PTS and with a history of DVT were recruited from nine centers in Brazil. The costs of investigations and treatment for PTS over a 1-year follow-up period were analyzed. Ninety patients were available for this analysis. RESULTS: Of the 90 patients, 17 had mild-to-moderate PTS, and 73 had severe PTS. The patients with severe PTS tended to undergo more investigations and hospitalizations for PTS than those with mild-to-moderate PTS, although the differences between the two groups did not reach statistical significance. The mean annual cost of treating PTS in Brazilian Reais was 1214 R dollars (426 US dollars) for mild-to-moderate PTS and 3386 R dollars (1188 US dollars) for severe PTS. The difference was mainly due to significantly higher hospitalization costs in patients with severe PTS (704 R dollars/247 US dollars vs. 0 R dollars; p=0.044). CONCLUSION: These results suggest that PTS imposes substantial demands on health care resources in Brazil. The implementation of effective thromboprophylactic strategies could significantly reduce the incidence of DVT, and hence of PTS, potentially resulting in significant cost savings.     

Correlation of mastication and masticatory movements and effect of chewing side preference

The aims of this study were to correlate masticatory performance with mandibular movements during mastication, and to evaluate masticatory performance and mandibular movements of subjects with different types of mastication. Seventy-eight healthy dentate subjects were selected and divided into 2 groups: bilateral and unilateral chewers. This classification was set by using kinesiography during mastication of an artificial material. Unilateral mastication was defined as the majority of the cycles took place at one specific side. The same tracings used to define type of mastication were used to evaluate mandibular movements by means of its parameters. Masticatory performance was analyzed by comminution of the artificial material and a sieving method. Statistical analysis was performed by Spearman's correlation method, and Mann-Whitney and Student's t-test, when appropriate, at 5% significance level. No correlation was found between masticatory performance and parameters of mandibular movement during mastication. Bilateral chewers presented significantly better (p<0.05) masticatory performance than unilateral ones, however no differences in parameters of mandibular movement were found between groups. Within the limits of this study, it may be concluded that parameters of jaw movements during mastication are not related to masticatory performance, and that the presence of a preferred chewing side worsens mastication.     

Processed allografts and type I collagen conduits for repair of peripheral nerve gaps

Autografting is the gold standard in the repair of peripheral nerve injuries that are not amenable to end‐to‐end coaptation. However, because autografts result in donor‐site defects and are a limited resource, an effective substitute would be valuable. In a rat model, we compared isografts with Integra NeuraGen® (NG) nerve guides, which are a commercially available type I collagen conduit, with processed rat allografts comparable to AxoGen's Avance® human decellularized allograft product. In a 14‐mm sciatic nerve gap model, isograft was superior to processed allograft, which was in turn superior to NG conduit at 6 weeks postoperatively (P < 0.05 for number of myelinated fibers both at midgraft and distal to the graft). At 12 weeks, these differences were no longer apparent. In a 28‐mm graft model, isografts again performed better than processed allografts at both 6 and 22 weeks; regeneration through the NG conduit was often insufficient for analysis in this long graft model. Functional tests confirmed the superiority of isografts, although processed allografts permitted successful reinnervation of distal targets not seen in the NG conduit groups. Processed allografts were inherently non‐immunogenic and maintained some internal laminin structure. We conclude that, particularly in a long gap model, nerve graft alternatives fail to confer the regenerative advantages of an isograft. However, AxoGen processed allografts are superior to a currently available conduit‐style nerve guide, the Integra NeuraGen®. They provide an alternative for reconstruction of short nerve gaps where a conduit might otherwise be used. Muscle Nerve, 2008