Effects of electrical stimulation on periodontal tissue remodeling in rats.

BACKGROUND AND OBJECTIVE: Electric current is used to promote wound healing. However, it is unclear whether electrical stimulation contributes to gingival tissue remodeling. This study examined the effects of electrical stimulation on gingival tissue remodeling in a rat periodontitis model. MATERIAL AND METHODS: Male Wistar rats (n = 28, 8 wks of age) were divided into four groups of seven rats each. The control group did not receive any treatment for 6 wks. In the other groups, periodontitis was ligature-induced for 4 wks. After 4 wks, the rats with periodontitis were given daily electrical stimulation of 0, 50 or 100 µA for 2 wks. RESULTS: The periodontitis group stimulated with 0 µA showed a higher density of polymorphonuclear leukocytes and a lower density of collagen in gingival tissue compared with the control group (p < 0.05). The two remaining groups treated with 50 or 100 µA of electrical stimulation exhibited a lower density of polymorphonuclear leukocytes (p < 0.05) and a higher density of collagen than the group stimulated with 0 µA (p < 0.05). They also showed higher expression of fibroblast growth factor-2 than the group treated with 0 µA of electrical stimulation (p < 0.05). CONCLUSION: Electric stimulation may offer a novel approach to promote gingival tissue remodeling in periodontal lesions.

[Successful treatment applied to methicillin-resistant Staphylococcus aureus (MRSA) empyema after the operation for lung cancer; report of a case].

Empyema caused by methicillin-resistant Staphylococcus aureus (MRSA) remains an intractable infection producing high mortality. The authers report a case of MRSA empyema following video-assisted thoracic surgery (VATS) for lung cancer. The case was 73-year-old male with some risks such as pulmonary emphysema, decreased renal function, and previous history of brain infarction. He received wedge resection and the staple lines were wrapped with polyglycolic acid (PGA) felt. Ten days after the operation, he was complicated MRSA pyothorax. By thoracoscopic procedures under local anesthesia, fibrinopurulent tissues were cleaned and 3 of chest tubes were replaced. Intrathoracic infected space was cleaned with physiological saline solution. The patient made favorable progress and recovered. Further empyema has not been developed for 24 months. VATS under local anesthesia and irrigation technique was safe and so useful. Nowadays, PGA felt is often used to reinforce the staple lines of lung. PGA felt is an absorbable but artificial material. We have to care about infectious problems. However, we could control the MRSA pyothrax without removing the PGA felt.

[Usefulness of the thoracoscopic surgery under local anesthesia and irrigation for the patient with Bacillus cereus empyema; report of a case].

The case was 54-year-old male with some risks such as chronic heart failure, atrial fibrillation, and liver chirrhosis. He was admitted because of severe back pain and diagnosed as empyema by preoperative thoracentesis. By thoracoscopic procedures under local anesthesia, fibrinopurulent tissues were cleaned as much as possible and 3 of chest tubes were replaced. The final diagnosis was Bacillus cereus pyothorax by bacterial cultures of pleural effusion. Intrathoracic cavity was cleaned with physiological saline solution. The patient made favorable progress and recovered. Thoracoscopic surgery under local anesthesia with thoracic irrigation was so effective and safe methods to control the infection.

Effects of an anti-angiogenic agent, TNP-470, on the growth of oral squamous cell carcinomas.

Anti-tumor effects of an anti-angiogenic agent, TNP-470, on the growth of oral squamous cell carcinomas (SCCs) were evaluated in vivo and in vitro. The growth of an oral SCC cell line, HSC-2, inoculated subcutaneously in severe combined immuno-deficiency (SCID) mice was inhibited in a dose-dependent manner by the treatment with this agent. A reduction of microvessels surrounding tumor tissues treated with TNP-470 was observed by immunohistochemistry. Significant side-effects were not observed except for weight loss during the period of treatment with high dose (50 mg/kg) of TNP-470. The direct effects of TNP-470 on oral SCC cell lines were also evaluated in culture. The growth of all eight SCC cell lines tested was inhibited by TNP-470, but the sensitivity of the oral SCC cell lines to TNP-470 was about 1700 times less than that of endothelial cells. These results suggest that TNP-470 inhibits the growth of oral SCC by anti-angiogenic activities and that it may be effective as a new therapy of oral cancer.

Evaluation of serum concentration of parathyroid hormone-related protein and its implication in hypercalcemia in squamous cell carcinoma of the head and neck.

Hypercalcemia is a common and serious complication associated with squamous cell carcinoma (SCC) and is considered to be caused by a tumor-derived factor, parathyroid hormone-related protein (PTHrP). However, the correlation between serum levels of calcium and PTHrP and the kinetics of PTHrP in SCC of the head and neck is unknown, because the behavior of the circulating form of PTHrP in patients has not been determined. In the present study, the PTHrP concentrations in serum samples from 54 patients (37 with SCC and 17 with benign tumors) were measured by a recently developed radioimmunoassay directed toward the C-terminal region of PTHrP, and the laboratory data including those calcium levels in corresponding samples were reviewed retrospectively. Results showed hypercalcemia in four patients with advanced cancer and in whom elevation of the serum PTHrP concentration was observed simultaneously. The regression analysis also revealed the linear relationship of the calcium level to the PTHrP concentration, but not to the concentration of phosphorus or creatinine, suggesting that monitoring of serum PTHrP level is useful for prediction of hypercalcemia associated with head and neck cancer.

Mineralized nodule formation in rat bone marrow stromal cell culture without beta-glycerophosphate.

Rat bone marrow stromal cells were cultured in the presence of 10 nM dexamethasone and various concentrations of beta-glycerophosphate. At day 12-15, some nodules consisting of polygonal cells were formed in all culture conditions, and these nodules were mineralized 2-3 days later. beta-Glycerophosphate significantly enhanced nodule formation at concentrations of not less than 5 mM. The mineralized nodules formed in the absence of beta-glycerophosphate were examined using phase-contrast microscopy, undemineralized and demineralized tissue histology, histochemistry for alkaline phosphatase, immunohistochemistry for type I, II, and III collagen, energy dispersive X-ray microanalysis, electron diffraction, and Fourier transform infrared spectroscopy (FT-IR). Mineralized nodules had histological characteristic similar to bone. Cells associated with nodules exhibited high alkaline phosphatase activity, and extracellular matrix of the nodules predominantly consisted of type I collagen. X-Ray microanalysis showed the presence of Ca and P in the mineralized area, and electron diffraction pattern showed the mineral to have apatite crystal structure. Moreover FT-IR indicated that the mineral was a mixture of hydroxyapatite and carbonateapatite. From these observations, it is concluded that the mineralized nodules formed in our culture system are truly bone-like.

[An early cancer of the descending colon, histologically showing a poorly differentiated adenocarcinoma].

Reported is the case of a 71 year-old male with a poorly differentiated adenocarcinoma of the colon that had invaded the submucosal layer. A barium enema had revealed a polyp, 1.5 cm in diameter, in the descending colon, and an endoscopic polypectomy was performed. The resected specimen mainly consisted of an adenoma and a partial, poorly differentiated adenocarcinoma that had massively infiltrated into the submucosal layer. A left hemicolectomy was carried out, and no carcinoma was identified in the resected colon and/or the regional lymph nodes.

In vitro mineralization of osteoblastic cells derived from human bone.

Osteoblastic cells were isolated from human maxilla by embedding the bone pieces in collagen gel. The isolated cells could be maintained in monolayer culture up to 50 population doubling levels (PDLs). Both parathyroid hormone (PTH) and prostaglandin E2 (PGE2) increased intracellular cyclic AMP level of the cells. The cells also showed high level of alkaline phosphatase (ALPase) activity and formed mineralized areas in monolayer culture. Electron microscopy demonstrated that these cells were surrounded by numerous well-banded collagen fibrils, among which matrix vesicles were scattered. It was also observed that needle-shaped crystals protruded from some matrix vesicles. These protruded crystals appeared to deposit along the collagen fibrils and a mineralized matrix was formed. The minerals of mineralized matrix mainly consisted of calcium and phosphorus and had the same Ca/P ratio as hydroxyapatite. These results indicate that the cells derived from human bone have characteristics of osteoblastic cells.