Experimental changes in mineral content of juvenile mouse femora

Summary Juvenile laboratory mice were exposed to hypergravity (8 g), burrowing exercise, swimming to exhaustion, an anabolic steroid, and swimming and an anabolic steroid for 30 days to determine the variability of skeletal mineralization during growth. Changes in mineralization were correlated with changes in bending strength. Experimental mouse femora were loaded to failure in a cantilever beam configuration to determine bending strength, and ashed to determine total mineral content. Between experimental groups, mineral content ranged from 66.0 to 71.2% with the greatest change from the control being a 4.7% decrease in mineralization in the male swimming exercise group (P<0.001). Within two age-matched experiments, the first showed that the group with the greatest decrease in mineralization also had the greatest reduction in bending strength (P<0.001). The second age-matched experiment showed that the group with the greatest reduction in mineralization had bending strength greatly reduced (P<0.001). However, in this experiment, the weakest femora were in the anabolic steroid group that did not have the mineral content reduced. We conclude that (1) mineralization of juvenile mouse femora is extremely variable given varied conditions of exercise or loading; (2) mineralization of normal bone is decreased more often and to a greater extent than increased from normal exercise controls; (3) the decrease in mineralization seen here can decrease bending strength; and (4) the decrease in mineralization seen was not caused by a decrease in mechanical loading but was probably due to a corticosterone-mediated psychological stress response. Therefore, two variables were indicated, one anabolic (mechanical loading) and one catabolic (corticosterone).     

Characterization of monofloral honeys by ash contents through a hierarchical design

With increasing world interest in honey characterization various studies have been carried out relating physicochemical parameters to botanical and geographical origins. Ash content is one of these parameters that has been associated with floral sources of honey samples. However, little attention has been given to the determination of how much of the variability in ash contents is caused by contributions of different floral sources or honey samplings compared to the variations caused by analytical errors. So, in this work, a two stage hierarchical statistical design is employed to quantify the sizes of these different variational sources. An extremely significant effect on ash content owing to floral origin of Eucalyptus and Citrus honey samples was found. A smaller but significant variation was also observed for different samples from the same floral source. This sampling variance can be associated with different environmental and geographical conditions, different technological aspects of production and processing of honeys since the honey samples were obtained from various beekeepers and collected in diverse regions of São Paulo State, Brazil. Considering that the variation owing to floral source is much larger than the one observed for sampling and analysis errors, ash content could be used to characterize these two types of monofloral honeys.     

External fixation of the unstable zygomatic arch fracture

Fixation of unstable zygomatic arch fractures may be accomplished with a relatively noninvasive approach using 24-gauge wire and modification of a readily available material, the orthopedic finger splint.     

Witoto ash salts from the Amazon

Ethnopharmacological relevance

This article presents the results of an anthropological and ethnobotanical study of the vegetable salts used by the Witoto Indians of the Amazon. It thoroughly documents the species used, the processing of the salts, their chemical composition and their anthropological, nutritional and medicinal relevance.

Materials and methods

Salts from 57 plant species known to the Witoto were processed using the same materials and techniques employed by the Indians: burning plant material, lixiviating the ashes with water, and boiling down the brine to desiccate the salt. Chemical analyses of macroelements of 49 of the salts, and of microelements of 24, were conducted. Tests on the taste of the salts as perceived by the native persons were carried out.

Results

Average ratio ashes/raw material was 3.05% (from 0.71% to 10.14%); average ratio dry salt/ashes was 11% (from 1% to 37%). All the samples analyzed presented a high proportion of potassium (26.9-44.6%); contents of phosphorus, sodium, calcium and magnesium were less than 1%; contents of carbonate, chloride and sulfate varied greatly among the salts. Boron, molybdenum and vanadium were present in all or almost all the samples analyzed; copper, barium and strontium were also frequent; manganese, zinc and iron were less frequent.

Conclusions

There is a correlation between the concentration of the three anions and the perceived taste of the salts, the “sweet” flavor of chloride being the preferred taste. Our research shows that the culinary function of these salts is secondary to their ritual, medicinal and cosmological meaning. The search for chloride is one of the reasons to produce and consume these salts; other reasons are also important: their alkaline pH, which liberates the alkaloid of the tobacco with which the salts are mixed; and their contents of microelements, which, although not discernible in taste, are inferred from symbolic associations of the species used.     

The effectiveness of respiratory protection worn by communities to protect from volcanic ash inhalation. Part I: Filtration efficiency tests

During volcanic eruptions and their aftermath, communities may be concerned about the impacts of inhaling volcanic ash. Access to effective respiratory protection (RP) is therefore important for many people in volcanic areas all over the world. However, evidence to support the use of effective RP during such crises is currently lacking. The aim of this study was to build the first evidence base on the effectiveness of common materials used to protect communities from ash inhalation in volcanic crises.We obtained 17 forms of RP, covering various types of cloth through to disposable masks (typically used in occupational settings), which communities are known to wear during volcanic crises. The RP materials were characterised and subjected to filtration efficiency (FE) tests, which were performed with three challenge dusts: ashes from Sakurajima (Japan) and Soufrière Hills (Montserrat) volcanoes and aluminium oxide (Aloxite), chosen as a low-toxicity surrogate dust of similar particle size distribution. FE tests were conducted at two concentrations (1.5?mg/m³ and 2.5?mg/m³) and two flow rates (equivalent to 40 and 80?l/min through 15.9?cm² sections of each RP type). Each material was held in a sample holder and PM_2.5 dust concentrations were measured both outside the mask material and inside the sample holder to determine FE. A limited number of tests were undertaken to assess the effect on FE of wetting a bandana and a surgical mask, as well as folding a bandana to provide multiple filter layers.Overall, four RP materials performed very well against volcanic ash, with median FEs in excess of 98% (N95-equiv., N99-equiv., PM_2.5 surgical (Japan), and Basic flat-fold (Indonesia)). The two standard surgical masks tested had median FEs of 89–91%. All other materials had median FEs ranging from 23 to 76% with no cloth materials achieving >44%. Folding a bandana resulted in better FE (40%; 3× folded) than single-layered material (29%). Wetting the bandana and surgical mask material did not improve FE overall.This first evidence base on the FE of common materials used to protect communities in volcanic crises from ash inhalation has been extended in a companion study (Steinle et al., 2018) on the total inward leakage of the best-performing masks when worn by human volunteers. This will provide a complete assessment of the effectiveness of these RP types.     

Nondestructive determination of iliac crest cancellous bone strength by pQCT

The close relationship between apparent bone density and compressive strength is well established. In clinical situations, histomorphometry, and determination of the compressive strength on bone biopsies are destructive methods and require two separate biopsies from each patient. The aim of this study was to evaluate whether volumetric bone density measured by peripheral quantitative computed tomography (pQCT) could be used as a nondestructive method for estimating trabecular bone strength of iliac crest bone biopsies, thereby allowing the same biopsy to be used for subsequent histomorphometry. Materials consisted of trabecular bone samples prepared from unilateral transiliac crest bone samples obtained at autopsy [total 95 specimens; 41 females (21–90 years) and 54 males (23–87 years)]. From these, the apparent density of the cancellous bone was evaluated by pQCT in a 1-mm-thick slice in the middle of the biopsy and also by ash density measurement. Bone strength was measured by compression test. A strong power relationship was found between density measured by pQCT and compressive strength (r = 0.93, p < 0.00001). Likewise, there was a strong power relationship between ash density and compressive strength (r = 0.97, p < 0.00001). A linear correlation was found between pQCT measurement and ash density (r = 0.98, p < 0.00001), indicating a very high accuracy for the pQCT measurement. In conclusion, pQCT provides a very good estimate of cancellous bone strength. This nondestructive assessment of strength of iliac crest bone biopsies thereby enables biomechanical information as well as histomorphometric measurements to be obtained from the same biopsy.     

Diabetes in the sand-rat: Diabetogenesis,responses to mannoheptulose and atriplex ash

Summary Diabetes was induced in sand rats by increasing the dietary intake of calories. The development of diabetes was followed by progressively greater hyper-glycaemic levels in the glucose tolerance test and the appearance of cataract, glucosuria and obesity. Ketonuria was never seen. Diabetic sand rats had a slightly elevated BMR and an RQ of approximately 1. They responded to D-mannoheptulose with hyperglycaemia but not with reduced RQ.Atriplex halimus ash did not reduce the hyperglycaemic response to glucose, though it has been reported to do so in alloxanized rats. Alloxanized rats were shown to retain responsiveness to D-mannoheptulose and it is speculated that response to D-mannoheptulose may be dependent on secretion of glucagon.Submitted in partial fulfillment of the requirements for the Ph. D. Degree.     

Young's modulus, bending strength, and tissue physical properties of human compact bone

The Young's modulus, bending strength, apparent density, and ash content of 155 human compact bone bending specimens were determined. Both Young's modulus (E) and bending strength (S) were strongly correlated to tissue dry apparent density (rho a). Based upon the correlation coefficient (R) and the percent deviation of the data from the regression curve (% dev.), these correlations were best described by power law relationships: E infinity rho a 1.54 (R2 = 0.79, % dev. = 2.4) and S infinity rho a 2.18 (R2 = 0.80, % dev. = 6.4). Bending strength was related to Young's modulus raised to the 1.26 power, implying a nonlinear relationship for these variables. We found a weak correlation between ash content and the mechanical behavior of the compact bone specimens, particularly Young's modulus, but could not statistically justify formulation of a more complex multivariate power model incorporating both density and ash content. Regional variations in strength and stiffness along the femoral shaft and within the cortex were also noted and were attributed primarily to differences in apparent density. The relationships formulated for the mechanical behavior of human compact bone are discussed in terms of the results of previous investigations of the mechanical behavior of nonhuman compact bone and human cancellous bone.