Intermittent parathyroid hormone 1-34 induces oxidation and deterioration of mineral and collagen quality in newly formed mandibular bone

Intermittent parathyroid hormone (PTH) administration is known to promote bone healing after surgical procedures. However, the mechanism and influence of PTH on the mineral and collagen quality of the jaw are not well understood. Most studies have focused on analyzing the bone density and microstructure of the mandible, and have insufficiently investigated its mineral and collagen quality. Oxidative stress activates osteoclasts, produces advanced glycation end products, and worsens mineral and collagen quality. We hypothesized that PTH induces oxidation and affects the mineral and collagen quality of newly formed mandibular bone. To test this, we examined the mineral and collagen quality of newly formed mandibular bone in rats administered PTH, and analyzed serum after intermittent PTH administration to examine the degree of oxidation. PTH administration reduced mineralization and worsened mineral and collagen quality in newly formed bone. In addition, total anti-oxidant capacity in serum was significantly decreased and the oxidative-INDEX was increased among PTH-treated compared to vehicle-treated rats, indicating serum oxidation. In conclusion, intermittent administration of PTH reduced mineral and collagen quality in newly formed mandibular bone. This effect may have been induced by oxidation

The Incidence of Oral and Oropharyngeal Cancers in Betel Quid-Chewing Populations in South Myanmar Rural Areas

Oral cancer is a very common disease in South and Southeast Asia. Betel quid (BQ)- chewing and tobaccosmoking habits are etiological factors for oral cancer patients in these regions. We conducted an oral cancer screening in BQ-chewing endemic rural areas in South Myanmar for the early detection of oral cancer in BQ-chewing and smoking individuals. We examined 105 subjects who were at high risk of oral cancer due to their oral habits (BQ users and/or smokers). Three carcinoma cases were detected, and there were 8 dysplasia cases. The carcinoma detection rate was 2.9%, and the carcinoma and precancerous lesion detection rate was 10.5%. In Myanmar, oral cancer screening has been conducted sporadically on a voluntary basis, and nationwide surveys have never been performed. There are also few reports of oral cancer screening for high-risk groups among the general population in Myanmar. Our present findings highlight the need for further screening and surveys. Education on betel quid chewing- and tobacco- related oral diseases and screening for the early detection of oral cancer are of the utmost importance in the control and prevention of oral cancer

Quality control of Photosystem II: Cleavage and aggregation of heat-damaged D1 protein in spinach thylakoids

AbstractModerate heat stress (40 °C, 30 min) on spinach thylakoids induced cleavage of the D1 protein, producing an N-terminal 23-kDa fragment, a C-terminal 9-kDa fragment, and aggregation of the D1 protein. A homologue of Arabidopsis FtsH2 protease, which is responsible for degradation of the damaged D1 protein, was abundant in the stroma thylakoids. Two processes occurred in the thylakoids in response to heat stress: dephosphorylation of the D1 protein in the stroma thylakoids, and aggregation of the phosphorylated D1 protein in the grana. Heat stress also induced the release of the extrinsic PsbO, P and Q proteins from Photosystem II, which affected D1 degradation and aggregation significantly. The cleavage and aggregation of the D1 protein appear to be two alternative processes influenced by protein phosphorylation/dephosphorylation, distribution of FtsH, and intactness of the thylakoids