Effect of calcitonin on total body bone mineral contents of experimental osteoporotic rats determined by dual photon absorptiometry

Summary Total body bone mineral (TBBM) content in rats was measured by dual photon absorptiometry (DPA). TBBM showed significant increases over 4 weeks in control groups with significant bone loss over the same time in prednisolone-injected rats on low calcium feed. Daily injections of calcitonin significantly reduced loss of bone mass. Both prednisolone- and prednisolone-calcitonin-injected groups showed significantly elevated serum alkaline phosphatase with the prednisolone-calcitonin group also exhibiting elevated serum calcium and phosphate levels, confirming the impact of the experimental protocol. TBBM measured by DPA in all groups correlated well (r=0.928,P<0.001 n=20) with the total ash weight suggesting that the method reflects total skeletal mineral content in the small animal. TBBM measurement by DPA proves well-suited to monitoring bone mineral in a small animal experimental setting.     

Personalized Blood Flow Restriction Therapy: How,When and Where Can It Accelerate Rehabilitation After Surgery?

Personalized (based on a percentage of a patient's limb occlusion pressure) blood flow restriction is emerging as a potential advancement in orthopaedic surgery. Safe application of the technology requires the use of medical devices capable of customizing the pressures applied to individual patients. In those circumstances, it is a low risk and noninvasive technique. By limiting muscle atrophy and aiding in the recovery of strength and function, it has the potential to significantly reduce the morbidity from limb trauma and surgery, and aid in achieving a substantially earlier return to full activity.     

The effectiveness of respiratory protection worn by communities to protect from volcanic ash inhalation. Part II: Total inward leakage tests

Inhalation of ash can be of great concern for affected communities, during and after volcanic eruptions. Governmental and humanitarian agencies recommend and distribute a variety of respiratory protection (RP), most commonly surgical masks. However, there is currently no evidence on how effective such masks are in protecting wearers from volcanic ash. In Part I of this study (Mueller et al., 2018), we assessed the filtration efficiency (FE) of 17 materials from different forms of RP against volcanic ash and a surrogate, low-toxicity dust, Aloxite. Based on those results, we now present the findings from a volunteer simulation study to test the effect of facial fit through assessment of Total Inward Leakage (TIL).Four different disposable RP types that demonstrated very high median FE (≥96% for Aloxite; ≥89% for volcanic ash) were tested without provision of training on fit. These were an industry-certified mask (N95-equiv.); a surgical mask from Japan designed to filter PM_2.5; a flat-fold basic mask from Indonesia; and a standard surgical mask from Mexico, which was also tested with an added medical bandage on top, as an additional intervention to improve fit.Ten volunteers (6 female, 4 male) were recruited. Each RP type was worn by volunteers under two different conditions simulating cleaning-up activities during/after volcanic ashfall. Each activity lasted 10?min and two repeats were completed for each RP type per activity. Dust (as PM_2.5) concentration inside and outside the mask was measured with two TSI SidePak aerosol monitors (Models AM510 and AM520, TSI, Minnesota, USA) to calculate TIL. A questionnaire was administered after each test to collect perceptions of fit, comfort, protection and breathability.The best-performing RP type, across both activities, was the industry-certified N95-equiv. mask with 9% mean TIL. The standard surgical mask and the basic flat-fold mask both performed worst (35% TIL). With the additional bandage intervention, the surgical mask mean TIL improved to 24%. The PM_2.5 surgical mask performed similarly, with 22% TIL. The N95-equiv. mask was perceived to provide the best protection, but was also perceived as being uncomfortable and more difficult to breathe through.This study provides a first objective evidence base for the effectiveness of a selection of RP types typically worn around the world during volcanic crises. The findings will help agencies to make informed decisions on the procurement and distribution of RP in future eruptions.     

Hot ash burns in the children of Western Australia: How and why they happen

Introduction

Burns from hot ash are common in the paediatric population in Western Australia. Fifty children were admitted to the paediatric burn centre with hot ash contact burns to the feet in 2011 and 2012. It is important to examine the extent of the problem, seasonal variations, and identify those at risk to determine strategies for prevention campaigns.

Method

Retrospective review of medical notes for all admissions to the paediatric burns unit was undertaken for 2011 and 2012. Data were collected for patient demographics, time, circumstance of injury, burn severity and treatment.

Results

Hot ash burns accounted for 8.6% of admissions but 16.1% of burns sustained in non-metro areas. Median age was just under 3 years, male or female. Median burn TBSA was 2%, and 44% of children required surgery. The burns were less common in summer, more common on non-school days and in children who were on camping trips away from home.

Discussion

Previous work has shown the value of targeted campaigns. The group for targeted prevention campaigns are the carers of very young children who go camping. Information distributed at camping shows and stores about the principles of campfire safety would reach the people at risk.     

Time course of systemic oxidative stress and inflammatory response induced by an acute exposure to Residual Oil Fly Ash

It is suggested that systemic oxidative stress and inflammation play a central role in the onset and progression of cardiovascular diseases associated with the exposure to particulate matter (PM). The aim of this work was to evaluate the time changes of systemic markers of oxidative stress and inflammation, after an acute exposure to Residual Oil Fly Ash (ROFA). Female Swiss mice were intranasally instilled with a ROFA suspension (1.0 mg/kg body weight) or saline solution, and plasma levels of oxidative damage markers [thiobarbituric acid reactive substances (TBARSs) and protein carbonyls], antioxidant status [reduced (GSH) and oxidized (GSSG) glutathione, ascorbic acid levels, and superoxide dismutase (SOD) activity], cytokines levels, and intravascular leukocyte activation were evaluated after 1, 3 or 5 h of exposure. Oxidative damage to lipids and decreased GSH/GSSG ratio were observed in ROFA-exposed mice as early as 1 h. Afterwards, increased protein oxidation, decreased ascorbic acid content and SOD activity were found in this group at 3 h. The onset of an adaptive response was observed at 5 h after the ROFA exposure, as indicated by decreased TBARS plasma content and increased SOD activity. The observed increase in oxidative damage to plasma macromolecules, together with systemic antioxidants depletion, may be a consequence of a systemic inflammatory response triggered by the ROFA exposure, since increased TNF-α and IL-6 plasma levels and polymorphonuclear leukocytes activation was found at every evaluated time point. These findings contribute to the understanding of the increase in cardiovascular morbidity and mortality, in association with environmental PM inhalation.     

龙芽百合质量的研究

目的对龙芽百合的质量进行研究。方法根据《中国药典》(2000年版一部)附录IX水分测定第一法,附录IXK灰分测定法,附录XA浸出物测定法测定龙芽百合的水分、水溶性浸出物、醇溶性浸出物含量和总灰分的含量。结果测得15批中药材龙芽百合的水分平均含量为11.35%;总灰分平均含量为3.07%;冷浸法和热浸法水溶性浸出物平均含量分别为20.51%和36.6%;60%乙醇浸出物含量平均值为21.81%。结论中药材龙芽百合的含水量不得超过14.0%,总灰分含量不得高于3.60%,冷浸法水溶性浸出物含量不得低于9.00%,热浸法水溶性浸出物含量不得低于27.50%,60%乙醇浸出物量含量不低于19.0%。     

Increase of bone volume in vitamin D-repleted rats by massive administration of 24R,25(OH)2D3

Summary A large dose of 24R,25(OH)₂D₃ was administered to the vitamin D-repleted rat to examine its effect on the bone. Male Wistar rats were fed a diet containing 0, 0.025, 1.25, 4.0, and 12.5 ppm 24R,25(OH)₂D₃ for 2 years starting at age 6 weeks. The estimated amounts of daily intake of 24R,25(OH)₂D₃ were 0, 93, 4640, 14680, and 49580 ng/100 g body weight, respectively. No notable difference was found in either the weight or the death rate of the animal. The long-term administration of massive doses of 24R,25(OH)₂D₃ did not lead to hypercalcemia nor did it affect the blood phosphorus, alkaline-phosphatase, or creatinine levels. Radiographs revealed a striking increase in the bone density on the bones from the animals treated with 1.25 ppm or more 24R,25(OH)₂D₃. Direct single photon absorptiometry revealed a dose-dependent increase in total bone minerals of both the femur and coccyx. Histological examination revealed a marked increase in the cortical thickness of the femur as well as in the cancellous bone volume of the coccyx. Polarizing microscopy demonstrated the lamellar structure of the bone, and undecalcified sections confirmed the increase of mineralized bone. Ash weight, calcium, phosphorus, and magnesium contents on the tibia and fibula also indicated the ascending dose-dependent increase up to 150% of the control. The parameters of bone size were not altered in any group. These results clearly suggest that 24R,25(OH)₂D₃ given in massive doses has the pharmacological action of increasing bone volume in the rat without causing remarkable hypercalcemia.     

Comparison insight dual X-ray absorptiometry (DXA), histomorphometry,ash weight,and morphometric indices for bone evaluation in an animal model (the orchidectomized rat) of male osteoporosis

The mechanical properties of dentin are largely determined by the intertubular dentin matrix, which is a complex composite of type I collagen fibers and a carbonate-rich apatite mineral phase. We performed a small angle X-ray scattering (SAXS) study on fully mineralized human dentin to quantify this fiber/mineral composite architecture from the nanoscopic through continuum length scales. The SAXS results were consistent with nucleation and growth of the apatite phase within periodic gaps in the collagen fibers. These mineralized fibers were perpendicular to the dentinal tubules and parallel with the mineralization growth front. Within the plane of the mineralization front, the mineralized collagen fibers were isotropic near the pulp, but became mildly anisotropic in the mid-dentin. Analysis of the data also indicated that near the pulp the mineral crystallites were approximately needle-like, and progressed to a more plate-like shape near the dentino-enamel junction. The thickness of these crystallites, approximately 5 nm, did not vary significantly with position in the tooth. These results were considered within the context of dentinogenesis and maturation.     

Accuracy and precision study in vitro for peripheral quantitative computed tomography

We evaluated the accuracy and precision of a peripheral quantitative computed tomography (pQCT) scanner, the Stratec XCT-960, using 12 human cadaveric forearms. The accuracy was determined by comparing the total bone mineral content (BMC) with the ash weight (AW). We scanned and ashed three consecutive slices (thickness 2.5 mm) at the standard position (s-position) and at 2.5 mm both proximal and distal to the s-position. The correlation coefficient between the AW and total BMC using slices at the s-position wasr=0.87 with an accuracy error (random component) of 15.5%. The correlation coefficient using all slices wasr=0.90 with an accuracy error of 14.3%. The correlation coefficient improved tor=0.95 with an accuracy error of 9.7% after averaging the results of all three slices for each forearm. The short-term precision error expressed as the coefficient of variation (CV) of bone mineral density (BMD) and BMC was determined by measuring the forearms five times either with repositioning or without repositioning. The CVs with repositioning were 2.77 and 1.15 for total BMD and BMC, 1.85 for trabecular BMD; without repositioning they were 0.29, 0.58 and 0.69 respectively. To further evaluate the influence of positioning, additional scans were performed at 1, 2 and 5 mm proximal, and 1 and 2 mm distal to the s-position. BMD and BMC were greatly influenced by the scan location; for example, the percentage differences in trabecular BMD 1 mm distal and proximal relative to the s-position were 2.5%±5.1% and 0.18%±6.3%, respectively. The Stratec XCT-960 appears to be a moderately accurate and highly precise scanner with potential usefulness for evaluating BMC and BMD of ultradistal radius.