Matos Marques

The influence of thyroid hormones on periodontitis-related bone loss and tooth-supporting alveolar bone: a histological study in rats

BACKGROUND AND OBJECTIVE Recent studies have pointed to potentially periodontal risk indicators, however no information is available on the impact of changes in thyroid hormone levels on the progression of periodontitis and on the quality of alveolar bone. Thus, the aim of the present study was to evaluate histologically, in rats, the influence of thyroid hormones on the rate of periodontal bone loss resulting from ligature placement and on the quality of tooth-supporting alveolar bone. MATERIAL AND METHODS Thirty-six male Wistar rats were randomly assigned to the following groups: healthy (control, n = 12), hypothyroidism (n = 12) and hyperthyroidism (n = 12). Once alterations were confirmed by total serum levels of triiodothyronine and thyroxine, ligatures were randomly placed around one of the first mandibular molars. Thirty days later, the animals were killed and specimens routinely processed for serial decalcified sections. The parameters assessed were periodontitis-related bone loss, quality of tooth-supporting alveolar bone and the number of cells positive for tartrate-resistant acid phosphatase (TRAP), a marker of bone resorption. RESULTS At the ligated sites, intergroup analysis revealed that hypothyroidism significantly increased the bone loss resulting from ligature-induced periodontitis (p = 0.02) and the number of TRAP-positive cells on the linear surface of bone crest (p = 0.01). In addition, no significant differences were detected regarding the quality of the bone (p = 0.24) or the number of TRAP-positive cells in the area of the interradicular bone for ligated teeth among the groups (p = 0.17). CONCLUSION It may be concluded that decreased serum levels of thyroid hormones may enhance periodontitis-related bone loss, as a function of an increased number of resorbing cells, whereas the tooth-supporting alveolar bone seems to be less sensitive to alterations in hormone levels.

Parathyroid hormone administration may modulate periodontal tissue levels of interleukin‐6, matrix metalloproteinase‐2 and matrix metalloproteinase‐9 in experimental periodontitis

BACKGROUND AND OBJECTIVE Intermittent administration of the parathyroid hormone (1-34) has an anabolic effect on bone and it has been shown to reduce alveolar bone loss in experimental periodontitis models. The aim of the present study was to investigate the effect of parathyroid hormone on tissue degradation-related factors in an experimental periodontitis model in rats. MATERIAL AND METHODS Periodontitis was induced in seventy-six male Wistar rats using ligature around the lower right first molars. The animals were then treated with parathyroid hormone (1-34) (T-group) or vehicle (C-group), three times a week for 15 d (C15, T15) or 30 d (C30, T30). At each experimental time-point, the 19 rats were killed in each group and the gingival tissue around the first lower molar was removed and prepared for the following analyses: mRNA expression of interleukin-1 beta, interleukin-6, matrix metalloproteinase (MMP)-2 and MMP-9, and gelatinolytic activity of MMP-2 and MMP-9. Hemimandibles were decalcified, and serial sections were processed and analyzed for interleukin-6 immohistochemistry. Samples were also histochemically stained by tartrate-resistant acid phosphatase (TRAP) to evaluate the number of osteoclasts present. RESULTS Parathyroid hormone-treated samples showed decreased of levels of mRNA for interleukin-6 in the T30 group (p < 0.01) and of MMP-2 in the T15 and T30 groups (p < 0.05). Zymography assays demonstrated that treatment with parathyroid hormone led to a decrease in MMP-9 activity (p < 0.01). TRAP staining of alveolar bone revealed that osteoclasts were present in higher numbers (p < 0.05) in the groups not treated with parathyroid hormone. CONCLUSION These data suggest that intermittent administration of parathyroid hormone can down-regulate the expression of biomarkers responsible for connective tissue breakdown and bone resorption, and potentially affect alveolar bone resorption activity.

Alcohol intake may impair bone density and new cementum formation after enamel matrix derivative treatment: histometric study in rats

BACKGROUND AND OBJECTIVE Alcohol intake may interfere with bone metabolism; however, there is a lack of information about the outcomes of regenerative approaches in the presence of alcohol intake. Enamel matrix derivative (EMD) has been used in periodontal regenerative procedures resulting in improvement of clinical parameters. Thus, the aim of this histomorphometric study is to evaluate the healing of periodontal defects after treatment with EMD under the influence of alcohol intake. MATERIAL AND METHODS Twenty Wistar rats were randomly assigned to two groups: G1 = alcohol intake (n = 10) and G2 = non-exposed to alcohol intake (n = 10). Thirty days after initiation of alcohol intake, fenestration defects were created at the buccal aspect of the first mandibular molar of all animals from both groups. After the surgeries, the defects of each animal were randomly assigned to two subgroups: non-treated control and treated with EMD. The animals were killed 21 d later. RESULTS G1 showed less defect fill for non-treated controls. Bone density (BD) and new cementum formation were lower for G1 when compared to G2, for EMD-treated and non-treated sites. EMD treatment resulted in greater BD and new cementum formation in both groups and defect fill was not significantly different between groups in the EMD-treated sites. The number of tartrate-resistant acid phosphatase-positive osteoclasts was significantly higher in G1 when compared to G2 and in EMD-treated sites of both groups. CONCLUSION Alcohol intake may produce a significant detrimental effect on BD and new cementum formation, even in sites treated with EMD. A limited positive effect may be expected after EMD treatment under this condition.

Acute neonatal appendicitis: the potential value of laparoscopy as a diagnostic and therapeutic tool

Abstract Appendicitis is the most common cause of acute abdominal pain requiring surgical intervention in children, but it is very rare in infants and neonates. Nonspecific clinical features and low index of suspicion make its diagnosis and management particularly challenging, which may result in high chances of complications such as perforation and peritonitis, thus increasing morbidity and mortality. We present the case of a female late preterm newborn with bloody stools and bilious gastric aspirates on the second day of life. After 24 h of clinical, laboratory and radiological surveillance, which evidenced deterioration in the newborn’s condition, an exploratory laparoscopy was performed, showing generalized peritonitis and perforated inflammatory appendix. A laparoscopic appendicectomy was performed. Histology confirmed the appendicitis diagnosis. The authors enhance the value of diagnostic laparoscopy and its potential as a therapeutic tool in neonates.

External beam radiation therapy in pilocytic astrocytoma of cerebellum

Summary The authors describe a case report of a 28 years old woman, with the diagnosis of low-grade pilocytic astrocytoma of the cerebellum, treated with surgery followed by external beam radiotherapy. The purpose of this paper is to iIlustrate the threedimensional (3-D) radiotherapy planning, used in this case, as weIl as to perform a brief review of the literature.