Dietary boron does not affect tooth strength,micro-hardness,and density,but affects tooth mineral composition and alveolar bone mineral density in rabbits fed a high-energy diet

The objective of this study was to determine whether dietary boron (B) affects the strength, density and mineral composition of teeth and mineral density of alveolar bone in rabbits with apparent obesity induced by a high-energy diet. Sixty female, 8-month-old, New Zealand rabbits were randomly assigned for 7 months into five groups as follows: (1) control 1, fed alfalfa hay only (5.91 MJ/kg and 57.5 mg B/kg); (2) control 2, high energy diet (11.76 MJ and 3.88 mg B/kg); (3) B10, high energy diet + 10 mg B gavage/kg body weight/96 h; (4) B30, high energy diet + 30 mg B gavage/kg body weight/96 h; (5) B50, high energy diet + 50 mg B gavage/kg body weight/96 h. Maxillary incisor teeth of the rabbits were evaluated for compression strength, mineral composition, and micro-hardness. Enamel, dentin, cementum and pulp tissue were examined histologically. Mineral densities of the incisor teeth and surrounding alveolar bone were determined by using micro-CT. When compared to controls, the different boron treatments did not significantly affect compression strength, and micro-hardness of the teeth, although the B content of teeth increased in a dose-dependent manner. Compared to control 1, B50 teeth had decreased phosphorus (P) concentrations. Histological examination revealed that teeth structure (shape and thickness of the enamel, dentin, cementum and pulp) was similar in the B-treated and control rabbits. Micro CT evaluation revealed greater alveolar bone mineral density in B10 and B30 groups than in controls. Alveolar bone density of the B50 group was not different than the controls. Although the B treatments did not affect teeth structure, strength, mineral density and micro-hardness, increasing B intake altered the mineral composition of teeth, and, in moderate amounts, had beneficial effects on surrounding alveolar bone.     

Age-related variability in occlusal wear planes

Investigation of two populations of 136 individuals shows several patterns of occlusal wear plane change which are positively correlated with age. For individuals up to the age of 18, there is a characteristic pattern in which the occlusal wear planes of the mandibular teeth are lingually sloped and those of the maxillary dentition buccally sloped, with the exception of the maxillary premolars, which are also lingually sloped. The long axes of the mandibular teeth give them a lingual orientation relative to the maxillary teeth, and the long axes of the maxillary molars, by contrast, are buccally oriented. In the 18-30 age range for all sexes, the mandibular M1 becomes buccally sloped on its occlusal surface while the occlusal wear plane on the maxillary M1 becomes lingually sloped. Later age changes indicate a trend for the mandibular premolars to become buccally sloped, while the wear planes of the maxillary premolars remain lingually sloped. There is a corresponding tendency for the maxillary and mandibular second molars to undergo changes in the initial orientation of the occlusal wear planes.     

Cementum annulation and age determination in Homo sapiens. II. Estimates and accuracy

The cementum annulation aging technique was evaluated in a sample of 80 clinically extracted premolars (age range 11–70 years). Demineralized thin sections (7μm) stained with hematoxylin were used. The correlation (r) between age and adjusted count (number of annulations added to age of tooth eruption) was 0.78 for the entire sample (N = 73) and 0.86 for a subsample in which teeth with periodontal disease were excluded (N = 55). Standard error of the estimates ranged from 4.7 to 9.7 years depending on sex and health status of the tooth. The technique provided significantly better estimates for females than for males. The overall inaccuracy (mean absolute error) of the technique was 6.0 years, with a bias (mean error) of 0.26 years. Reduced major axis regression of adjusted count on age produced a slope of 0.797 for the entire sample and 0.889 for the nonperiodontal disease subsample. These slopes are consistent with a hypothesis of annual deposition of cementum rings given a decrease in cementogenesis with increasing age.     

Gingival eruption sequences of permanent teeth in early hominids.

Gingival eruption of the permanent teeth of Australopithecus, Paranthropus, and early Homo, diagnosed from enamel scratches and facets, is similar save for two sequences: eruption of the canines relative to the premolars which may be sexually dimorphic; and agenesis of M3 with delayed eruption of M2, first seen in Homo at two million years. Gingival eruption sequences are similar also for early and modern Homo, except that in some individuals today M3, M2, M1 and I2 take longer to form and emerge through the gingiva as functioning teeth. Probably, from two million years to the present in the evolutionary history of Homo dental development slowed-down. More and more of ontogeny has been taken over for eruption.     

Phytosaur remains (Reptilia,Thecodontia)from the Upper Triassic of North-Eastern Thailand

The recently discovered late Triassic vertebratelocality at Chulabhorn Dam (North-Eastern Thailand) has yielded incomplete remains (jaw fragments and teeth) of phytosaurs, which are apparently indicative of a form related to Belodon and Rutiodon. They can be interpreted as showing that in the late Triassic North-Eastern Thailand was already biogeographically part of Laurasia.     

The North American «Hipparion Datum and implications for the Neogene of the Old World

A large sample of skulls and associated dentitions of Cormohipparion sphenodus (Cope, 1889). new combination, is described from Miocene deposits of Nebraska, Colorado, New Mexico, and California. This species is morphologically more advanced than the most primitive species of the genus, C. goorisiMacFadden & Skinner, 1981, and more primitive than a third and more advanced species of this genus. C. occidentale (Leidy, 1856). In several characters such as configuration of the preobrital fossa, size, hypsodonty, shape of protocone, and complexity of enamel plication, C. sphenodus is morphologically similar, and potentially related to, some Old World Vallesian «Hipparion. In addition, based on radiometric calibration of stratigraphic sequences in Nebraska and California, C. sphenodus spans an interval of time from about 13.6 to 11 Ma. Inasmuch as the Old World «Hipparion Datum is calibrated at about 12 Ma, we conclude that C. sphenodus exhibits the morphological and chronological prerequisites to have been directly ancestral to some of these Old World forms.The hipparion horses apparently were a polyphyletic assemblage of several genera, and their biogeographic and biochronologic history is more complex than classically thought. Several dispersal events involving these horses may have occurred between the New and Old Worlds during the late Miocene.     

Additions a la faune de sélaciens fossilesdu Maroc: 1: Sur la présence des genres Heptranchias,Alopias etOdontorhytis dans l'Yprésien des Ouled Abdoun

Recent researches in the phosphat-bearing basins ofMorocco have allowed to collect new selachian forms. In this paper, three Ypresian genera from Ouled Abdoun basin, new for Morocco, are described: Heptranchias howellii (Reed, 1946), Alopias denticulatus nov. sp. and Odontorhytis pappenheimiBöhm, 1926. The re-discovery of the genus Odontorhytis allows to state precisely its morphological dental features and to affirm that it is well a selachian and not a teleostean, as it was thought. The stratigraphic distribution of some species is stated precisely.     

Multivariate analysis of Gigantopithecus mandibles

Multivariate analysis of measurements of the teeth and mandibles of Gigantopithecus species has been conducted, using several methods. Results indicate Gigantopithecus is an aberrant form, less related to australopithecines and gorillas than the latter are to each other. Gracile and robust australopithecines differ considerably more than do male and female gorillas.     

Achieving stable myocardial regeneration after apical resection in neonatal mice

The neonatal heart completely regenerates after apical resection (AR), providing a desirable research model to study the mechanism of cardiac regeneration and cardiomyocyte proliferation. However, AR-induced neonatal heart regenerative phenomenon is controversial due to the variation of operative details in different laboratories. Here, we provide an optimized AR operation procedure with stable regeneration and high survival rate by achieving heart exposure, normalizing myocardium cut-offs, and reducing operation duration. We also established a whole-heart-slice approach to estimate the myocardial regeneration after the AR operation, which ensures no false-negative/positive results. The combination of the optimized AR operation and the whole-heart-slice analysis provides a stable system to study neonatal heart regeneration and cardiomyocyte proliferation in situ.     

盐酸右美托咪定联合盐酸罗哌卡因胸椎旁神经阻滞对肺癌根治术患者血清炎性因子和免疫学指标的影响

摘要 目的：探讨盐酸右美托咪定联合盐酸罗哌卡因胸椎旁神经阻滞（TPVB）对肺癌根治术患者血清炎性因子和免疫学指标的影响。方法：选取2018年4月~2020年4月期间于我院行肺癌根治术的患者400例,根据信封抽签法分为对照组和观察组,各200例,对照组给予盐酸罗哌卡因TPVB,观察组在对照组基础上联合盐酸右美托咪定,对比两组疼痛、炎性因子、免疫学指标、血流动力学及不良反应。结果：观察组术后6 h（T5）~术后48h（T8）时间点视觉模拟评分法（VAS）评分均低于对照组（P<0.05）。对照组插管后5 min（T1）~术毕（T3）时间点心率（HR）及平均动脉压（MAP）较麻醉诱导前（T0）时间点升高（P<0.013）,观察组T1~T3时间点HR、MAP低于对照组（P<0.05）。两组T8时间点白介素-6（IL-6）、C反应蛋白（CRP）、肿瘤坏死因子-α（TNF-α）均较T0下降,且观察组低于对照组（P<0.05）。两组T8时间点CD4⁺、CD4⁺/CD8⁺均较T0时间点下降,但观察组高于对照组（P<0.05）,CD8⁺均较T0时间点升高,但观察组低于对照组（P<0.05）。观察组不良反应总发生率低于对照组（P<0.05）。结论：盐酸右美托咪定联合盐酸罗哌卡因TPVB用于肺癌根治术患者,可稳定血流动力学,且可获得较好的镇痛效果,降低不良反应发生率,减轻术后炎性损伤及免疫抑制。