Effectiveness and fabrication of mouthguards

Abstract –  Although mouthguards have been suggested as a means for preventing dental traumatic injuries, there are still some controversies over some aspects such as effectiveness in preventing concussions, material selections, method for fabrication, design, side effects and so on. The purpose of this literature review was to clarify differences in opinions with supporting evidence on these issues and find the best guidelines for promoting usage and providing mouthguards with better protective capability and fewer side effects such as difficulty in breathing and speaking.     

Perinatal changes in bombesin-stimulated muscle contraction in rabbit stomach and colon

Bombesin and its mammalian homologue, gastrin-releasing peptide, stimulate smooth muscle contraction and may promote the growth of gastrointestinal tissues. Isometric contraction of strips from circular muscle of the gastric fundus and longitudinal muscle of the distal colon were used to compare changes in the response to bombesin in newborn and weanling rabbits. There was an age-related qualitative change in gastric muscle from biphasic contractions including phasic and tonic components in the newborn to phasic contractions alone in the weanling. The colon contractions were tonic at both ages. In both tissues there was an age-related fivefold increase in stress in response to maximally effective concentrations of bethanechol (P less than 0.05). In contrast, in the stomach age-related decreases in the response to maximally effective concentrations of bombesin were observed, from 2930 +/- 179 mN/cm2 (98% of the maximal response to bethanechol) in the newborn to 565 +/- 81 mN/cm2 (4% of the maximal response to bethanechol) in the weanling (P less than 0.005). In the colon, a twofold increase in response to bombesin was observed, from 446 +/- 59 mN/cm2 (82% of the response to bethanechol) in the newborn to 862 +/- 11 mN/cm2 (29% of the response to bethanechol) in the weanling (P less than 0.05). No age-related changes were observed in the potency of bombesin in either tissue. Neither atropine nor tetrodotoxin altered the contractions in either tissue, suggesting that bombesin interacted directly with myocytes. There was three times as much bombesinlike immunoreactivity in the stomach compared with the colon, but no age-related changes in either tissue. In summary, by the age of weanling the stomach lost the tonic component of contraction and 80% of the efficacy of bombesin-stimulated phasic contraction that had been present in the newborn. The loss of efficacy, absolute in the stomach and relative to bethanechol in the colon, suggest that bombesin may be most important in stimulating motility in the neonatal period.     

Factors contributing to ribavirin dose reduction due to anemia during interferon alfa2b and ribavirin combination therapy for chronic hepatitis C

Background Recent studies indicate that combination therapy with ribavirin and interferon alfa2b (IFN2b) is effective for chronic hepatitis C virus (HCV) infection. However, reversible hemolytic anemia is a common side effect of this therapy.Methods We determined those factors that contribute to ribavirin dose reduction due to anemia during this treatment by using multiple logistic regression analysis in Japanese patients. The study included 123 patients with chronic hepatitis C (85 male, 38 female; mean age, 50 years; range, 20–70 years), who received 24-week combination therapy. All patients were treated with IFN2b daily for 2 weeks, followed by three times weekly dosing for 22 weeks, with oral ribavirin twice daily, at a total daily dose of 600 or 800mg.Results Of the 123 patients, 34 patients required dose reduction of ribavirin, and 78 patients required no dose reduction. Overall, 20 patients discontinued. On univariate analysis, reduction of the ribavirin dose correlated significantly with pretreatment hemoglobin (Hb) levels of less than 14g/dl, female sex, and patient age 55 years or older. On multivariate analysis, pretreatment Hb of less than 14g/dl level and age 55 years or older were significantly associated with ribavirin dose reduction. The hazard ratios were 3.56 (95% confidence interval [CI], 1.48–8.53) for pretreatment Hb levels of less than 14g/dl, and 2.50 (95% CI, 1.05–5.94) for age 55 years or more.Conclusions Because patient age of 55 years or more, and Hb levels of less than 14g/dl are significant factors that influence ribavirin-induced hemolytic anemia, more careful monitoring is necessary during combination therapy for patients with these risk factors.     

Pitavastatin, an HMG-CoA reductase inhibitor, exerts eNOS-independent protective actions against angiotensin II induced cardiovascular remodeling and renal insufficiency

Angiotensin II (Ang II) plays a pivotal role in cardiovascular remodeling leading to hypertension, myocardial infarction, and stroke. Pitavastatin, an HMG-CoA reductase inihibitor, is known to have pleiotropic actions against the development of cardiovascular remodeling. The objectives of this study were to clarify the beneficial effects as well as the mechanism of action of pitavastatin against Ang II-induced organ damage. C57BL6/J mice at 10 weeks of age were infused with Ang II for 2 weeks and were simultaneously administered pitavastatin or a vehicle. Pitavastatin treatment improved Ang II-induced left ventricular hypertrophy and diastolic dysfunction and attenuated enhancement of cardiac fibrosis, cardiomyocyte hypertrophy, coronary perivascular fibrosis, and medial thickening. Ang II-induced oxidative stress, cardiac TGFbeta-1 expression, and Smad 2/3 phosphorylation were all attenuated by pitavastatin treatment. Pitavastatin also reduced Ang II-induced cardiac remodeling and diastolic dysfunction in eNOS-/- mice as in wild-type mice. In eNOS-/- mice, the Ang II-induced cardiac oxidative stress and TGF-beta-Smad 2/3 signaling pathway were enhanced, and pitavastatin treatment attenuated the enhanced oxidative stress and the signaling pathway. Moreover, pitavastatin treatment reduced the high mortality rate and improved renal insufficiency in Ang II-treated eNOS-/- mice, with suppression of glomerular oxidative stress and TGF-beta-Smad 2/3 signaling pathway. In conclusion, pitavastatin exerts eNOS-independent protective actions against Ang II-induced cardiovascular remodeling and renal insufficiency through inhibition of the TGF-beta-Smad 2/3 signaling pathway by suppression of oxidative stress.     

Telmisartan treatment decreases visceral fat accumulation and improves serum levels of adiponectin and vascular inflammation markers in Japanese hypertensive patients.

Hypertension contributes to the occurrence and progression of cardiovascular diseases. The angiotensin II type 1 receptor blocker telmisartan is reported to activate the peroxisome proliferator-activated receptor gamma and improve insulin sensitivity. We investigated the effects of telmisartan treatment on visceral fat, serum adiponectin and vascular inflammation markers in Japanese hypertensive patients. This was an open-label, non-controlled study. Twenty-eight essential hypertensive patients (22 men and 6 women; age 60.6+/-1.9 years; body mass index [BMI] 25.5+/-0.6 kg/m(2)) participated. Fat area was assessed with computerized tomography. All the subjects were started on telmisartan 40 mg/day, which was increased to 80 mg/day to achieve the blood pressure target of less than 130/80 mmHg. We assessed the visceral and subcutaneous fat areas, serum adiponectin levels, and vascular inflammation markers at baseline and 24 weeks of telmisartan treatment. There were significant reductions in visceral fat area (from 103.1+/-7.9 to 93.3+/-8.4 cm(2), p<0.01) and pulse wave velocity (from 1,706+/-52 to 1,587+/-51 cm/s, p<0.01) at 24 weeks. In contrast, significant increases in serum high-density lipoprotein cholesterol (from 5.06+/-0.15 to 5.32+/-0.13 mmol/L, p<0.05) and adiponectin levels (from 8.27+/-0.76 to 9.13+/-0.81 microg/mL, p<0.05) were observed. Also, there were reductions in the interleukin-6 level (from 2.26+/-0.27 to 1.60+/-0.14 pg/mL, p<0.01). We also conducted these investigations in male subjects alone and similar findings were obtained for all of these parameters. In conclusion, telmisartan treatment was associated with an improvement of vascular inflammation, reductions in visceral fat and increases in serum adiponectin.     

Endoscopic submucosal dissection for cancers of the remnant stomach after distal gastrectomy

BACKGROUND: Endoscopic submucosal dissection (ESD) of early gastric cancer is less invasive than surgical resection, and if technically feasible, it may result in less long-term morbidity than does incisional surgery. However, ESD is technically difficult in patients who have had a previous distal gastrectomy. OBJECTIVE: Our purpose was to retrospectively assess the results of ESD of early gastric cancer in the remnant stomach. DESIGN: Case series. SETTING AND PATIENTS: A total of 31 lesions in 30 patients with early remnant gastric cancer were treated with ESD at Okayama University Hospital, Tsuyama Central Hospital, Hiroshima City Hospital, Kagawa Prefectural Central Hospital, and Mitoyo General Hospital from March 2001 to January 2007. INTERVENTION: ESD. MAIN OUTCOME MEASUREMENTS: En bloc resection rate, complete resection rate, operation time, and complications. RESULTS: En bloc resection and complete resection were achieved in 30 (97%) and in 23 (74%) lesions, respectively. The median operation time required for ESD in the remnant stomach was 113 minutes (range 45-450 minutes). Perforation occurred in 4 (13%). The incidence of delayed bleeding requiring blood transfusion was 0%. LIMITATION: Short duration of follow-up. CONCLUSIONS: ESD is feasible in the remnant stomach but has a relatively high complication rate and should only be performed by experienced endoscopists.