Histomorphometric Changes of the Masseter Muscle of Rats After a Single Injection of Botulinum Toxin Type A

BACKGROUND

It has been reported that botulinum toxin type A (BoNT-A) produces structural changes in masticatory muscles. However, not all histomorphometric parameters affected by BoNT-A parameters have been assessed. This study investigated the histomorphometric changes in the masseter muscle of rats after a single injection of BoNT-A.

METHODS

Forty-four adult animals were randomly divided into control group (n = 22) and BoNT-A group (n = 22). Controls received a single dose of 0.14 mL/kg of saline in masseter muscles, and the BoNT-A group received a 7 U/Kg of BoNT-A. The groups received the same volume of injected substances. Animals were sacrificed on 7th (n = 5), 14th (n = 5), 21st (n = 5), 28th (n = 4) and 90th (n = 3) days post-treatment. Histological masseter tissue slides were obtained from hematoxylin-eosin treatment and analyzed in optical microscopy regarding muscle cross-sectional area, amount of connective tissue and quantity and diameter of myocytes. For statistical analysis, generalized linear models were used to compare the data (ANOVA). In all test, the significance level of 5% was set.

RESULTS

BoNT-A values of cross-sectional area of the masseter muscle were significantly lower than controls (p < 0.01) throughout the study. Regarding myocytes quantity, BoNT-A subgroups presented higher values than controls (p < 0.0001) since the 14th day until the end of the study; however, the diameter of myocytes was smaller in all BoNT-A subgroups (p < 0.0001) in all assessment points. The amount of connective tissue was higher in BoNT-A subgroups (p < 0.0001) throughout the study.

CONCLUSION

A single injection of BoNT-A altered the structure of masseter muscle of rats, regarding its histomorphometric parameters.

NO LEVEL ASSIGNED

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The effects of low level laser irradiation on proliferation of human dental pulp: a narrative review

Mesenchymal stem cells (MSCs) have the capability for self-renewal, proliferation, and differentiation in various types of specialized cells, so they are very important in cellular therapies. MSC from dental pulp are simply obtainable and have high proliferative capability. Among the therapies that can stimulate the proliferation of certain cell types, low-level laser therapy (LLLT) stands out. The target of this study is to perform a literature review to investigate these effects of low-level laser irradiation on proliferation of human dental pulp.The electronic search of scientific papers was conducted in the Lilacs, Scielo, Medline and PubMed databases through scientific articles published in national and international journals in the past 20 years.The results of this review suggest that LLLT may be a useful and important tool for future advances in cell therapy and tissue engineering associated to stem cells. Studies on cell therapy for regenerating dental tissues has already been done, and shows promising results.

Meta-analysis of transcutaneous electrical nerve stimulation for relief of spinal pain

We conducted a systematic review and meta-analysis analysing the existing data on transcutaneous electrical nerve stimulation (TENS) or interferential current (IFC) for chronic low back pain (CLBP) and/or neck pain (CNP) taking into account intensity and timing of stimulation, examining pain, function and disability. Seven electronic databases were searched for TENS or IFC treatment in non-specific CLBP or CNP. Four reviewers independently selected randomized controlled trials (RCTs) of TENS or IFC intervention in adult individuals with non-specific CLBP or CNP. Primary outcomes were for self-reported pain intensity and back-specific disability. Two reviewers performed quality assessment, and two reviewers extracted data using a standardized form. Nine RCTs were selected (eight CLBP; one CNP), and seven studies with complete data sets were included for meta-analysis (655 participants). For CLBP, meta-analysis shows TENS/IFC intervention, independent of time of assessment, was significantly different from placebo/control (p < 0.02). TENS/IFC intervention was better than placebo/control, during therapy (p = 0.02), but not immediately after therapy (p = 0.08), or 1-3 months after therapy (p = 0.99). Analysis for adequate stimulation parameters was not significantly different, and there was no effect on disability. This systematic review provides inconclusive evidence of TENS benefits in low back pain patients because the quality of the studies was low, and adequate parameters and timing of assessment were not uniformly used or reported. Without additional high-quality clinical trials using sufficient sample sizes and adequate parameters and outcome assessments, the outcomes of this review are likely to remain unchanged.

SIGNIFICANCE

These data highlight the need for additional high-quality RCTs to examine the effects of TENS in CLBP. Trials should consider intensity of stimulation, timing of outcome assessment and assessment of pain, disability and function.

Ectopic cervical thymic carcinoma in a dog

A 10-year-old male German shepherd dog was referred for evaluation of a cranial cervical mass causing progressively worsening respiratory distress. A fine-needle aspirate of the mass was obtained and the cytology results were compatible with a carcinoma. The dog underwent chemotherapy without clinical improvement and was ultimately euthanased because of clinical deterioration. At post-mortem examination, an irregular multi-lobated mass in the cranial cervical region was observed causing ventro-lateral tracheal deviation. Histopathology and immunohistochemistry revealed a mixed population of CD3 lymphocytes and macrophages in an exuberant fibrous stroma, associated with dispersed cytokeratin-positive epithelial cells with marked eosinophilic cytoplasm. Some of the epithelial cells were arranged in concentric clusters that were interpreted as Hassall's corpuscles. Histopathological examination of the thyroid gland revealed several neoplastic emboli composed of epithelial cells similar to those observed in the cervical mass. To the authors' knowledge, this is the first report of an ectopic cervical thymic carcinoma in a dog.

Influence of dialysis duration and modality on kidney transplant outcomes

BACKGROUND

The influence of pretransplantation dialysis on kidney transplant outcomes has been the subject of longstanding interest. Although increased time on dialysis prior to kidney transplantation is associated with decreased graft and patient survivals, analyses of the impact of dialysis modality on kidney allograft outcome have produced conflicting results.

OBJECTIVE

The objective of this study was to evaluate the influence of dialysis duration and modality on the function and survival of renal allografts.

PATIENTS

We retrospectively reviewed the clinical data of 421 adults who received first kidney transplantations from cadaveric heart-beating donors performed in our unit from May 1989 to May 2007. Three hundred seventy-four patients (88.8%) were on hemodialysis (HD) prior to kidney transplantation, including 247 patients (58.7%) on treatment for at least 24 months.

RESULTS

Patients with a dialysis duration > or =24 months were significantly older (45.9 vs 42.8 years; P = .013). Renal function at 3, 12, 60, and 96 months was similar between the 2 groups. Longer duration on dialysis was associated with poorer overall graft and patient survivals. No differences were observed in renal function or graft and patient survivals comparing HD or peritoneal dialysis (PD). Multivariate analysis confirmed the lack of correlation between dialysis duration or modality and allograft failure.

CONCLUSION

Longer dialysis duration influenced overall graft and patient survival. However, dialysis modality showed no influence on graft function or survival.

Impact of donor age on renal allograft function and survival

BACKGROUND

The lack of cadaveric donors coupled with a rapidly growing number of potential recipients have stimulated the implementation of several strategies, including the acceptance of older donors, to increase the organ pool and reduce the waiting list for kidney transplantation. However several studies have demonstrated higher incidences of delayed graft function and poor graft outcomes among kidneys harvested from older donors.

OBJECTIVE

The objective of this study was to evaluate the influence of donor age on the function and long-term survival of renal allografts.

PATIENTS

We performed a retrospective review of the clinical data from 441 adult kidney transplantation from cadaveric heart-beating donors performed in our unit from May 1989 to May 2007.

RESULTS

Recipients of kidney allografts from older donors were significantly older (49.2 vs 43.7 years; P < .0001) and had a higher incidence of delayed graft function (15.1% vs 5.4%; P = .005). Renal function was superior following kidney transplantation using younger donors not only at 3 months (P < .0001) and 12 months (P < .0001) posttransplantation, but also upon long-term follow-up at 60 months (P < .0001) and 96 months (P = .030). Allograft survival censored for death with a functioning graft and patient survival were not different when comparing older versus younger donors. Multivariate analysis confirmed the lack of correlation between donor age and allograft failure.

CONCLUSION

Donor age showed no influence on allograft survival. However, kidney allografts from older donors displayed lower first year and long-term renal function.