Lead concentrations in cortical and trabecular bones in deceased smelter workers

The aim of the study was to compare bone lead concentrations in cortical and trabecular bones in long-term exposed primary copper and lead smelter workers, and to relate the measured concentrations to the previous lead exposure of the workers. Lead concentrations in seven bones (trabecular: sternum, vertebrae, iliac crest, rib; cortical: femur, left forefinger, and temporal bone) were determined by electrothermal atomic absorption spectrometry in 32 male, long-term exposed copper and lead smelter workers, and compared with levels in 10 male occupationally unexposed reference persons. A time-integrated blood lead index (cumulative blood lead index, CBLI) was calculated for each worker. The lead levels in the seven studied bones were all significantly higher in active and retired lead workers as compared with the reference group (p相似文献   

Lead in liver and kidney of exposed rats: Aging accumulation study

The concentration of lead in liver and kidneys of Wistar rats, fed with lead since fetal period in relation to their age and to a control group, was determined. A group of rats was exposed to lead acetate (n = 30) in drinking water and the other group was exposed to normal water (n = 20). Samples were collected from rats aging between 1 and 11 months and were analyzed by Energy Dispersive X-ray Fluorescence (EDXRF) without any chemical preparation. The EDXRF results were assessed by the PIXE (Proton Induced X-ray Emission) technique. The formaldehyde used to preserve the samples was also analyzed by ETAAS (Electro-Thermal Atomic Absorption Spectrometry) in order to verify if there was any loss of lead from the samples to the formaldehyde. We found that the loss was not significant (<2%).Concerning the mean values of the lead concentration measured in the contaminated soft tissues, in liver they range from 6 to 22 μg g^?1, and in kidneys from 44 to 79 μg g^?1. The control rats show, in general, values below the EDXRF detection limit (2 μg g^?1). The ratio kidney/liver ranges from 2 to 10 and is strongly positively correlated with the age of the animals. A Spearman correlation matrix to investigate the correlation between elemental concentrations and the dependence of these concentrations with age showed that there is a strong positive correlation with age for lead in the liver but not in the kidney. The correlation matrix showed also that the concentration of lead in these two soft tissues is not correlated. The lead accumulation in liver is made by different plateaus that strongly decrease with age. It was verified the existence of two levels of accumulation in kidney, not very highlighted, which might be indicative of a maximum accumulation level for lead in kidney.     

Quantitative genetic variation in the skeleton of the mouse: II. Description of variation within and between inbred strains

Variation in the skeletons of over 400 male and female mice from 12 genotypes was investigated by using multivariate statistical methods. A series of discriminant functions explains the differences in the shape of six bones: mandible, os coxae, femur, tibia-fibula, scapula, and humerus. The anatomical features of bone shape described by these functions are summarized together with illustrations of the typical shapes of each bone from the 12 genotypes. Variability within genotypes was investigated by using the Mahalanobis D2 distance--a measure of the difference between two points representing multivariate data--from the group mean. A series of variants were detected ranging from grossly abnormal bones to bones showing subtle differences localized to specific regions. Examples of the variants found are illustrated.     

Enhancement by lactosucrose of the calcium absorption from the intestine in growing rats

The effects of dietary lactosucrose on calcium absorption from the intestine and calcium accumulation in bones were investigated in growing female rats. The apparent calcium-45 ((45)Ca) absorption, residual (45)Ca ratio in the body, and (45)Ca accumulation in the femur and tibia of lactosucrose-supplemented rats were significantly higher than in control rats 24 h after the administration of a (45)CaCl(2) solution.     

The Zagreb Skull Collection—The unique identified collection of human skulls from fetuses to centenarians

Skull anatomy and development have been extensively studied due to their significance in evolutionary biology, forensic anthropology, and clinical medicine. Bone collections are an indispensable resource for conducting such anthropological and anatomical studies. However, worldwide there are only few skull collections containing specimens covering the entire fetal and postnatal period. Herein we describe the Zagreb Skull Collection, an identified collection comprising more than 1100 skulls and skull bone sets from the early fetal period to centenarians. The Zagreb Skull Collection consists of two main parts: the unique Collection of Skull Bones containing 386 sets of separated skull bones from the early fetal period to adulthood and the Collection of Skulls containing 742 skulls (age range 4–101 years). The collection was the core source for numerous anatomical studies on the development, postnatal changes, and anatomical variations of the skull. However, the Zagreb Skull Collection is still an underexploited resource for anthropological, forensic, and anatomical studies with translatability to contemporary clinical practice.     

Bone mechanical properties after exercise training in young and old rats

The effects of a 10-wk training regimen on the mechanical properties of the femur and humerus were evaluated in 2.5- and 25-mo-old Fischer 344 female rats. The rats trained on a rodent treadmill 5 days/wk for 10 wk. Duration, grade, and speed increased until the rats maintained 1 h/day at 15% grade and either 15 m/min (old rats) or 36 m/min (young rats). Excised bones were mechanically tested with a 3-point flexure test for mechanical properties of force, stress, and strain. Fat-free dry weight (FFW) and moment of inertia were also obtained. With aging, similar increases were observed in both the femur and humerus for FFW, moment of inertia, and force. Ultimate stress was reduced in the senescent femur while strain was elevated; a similar but nonsignificant trend was observed in the humerus. Irrespective of age, training increased FFW in the femur and, to a lesser degree, in the humerus. Breaking force was elevated for both bones after training. In young and old bones, the training-induced differences in bone mass and force were similar, despite differences in training intensity. In the old trained rats, femur ultimate stress was greater than that in control rat femurs and similar to that in young rat femurs. The results of the present study indicate that training effects were not limited by age.     

Adaptation of bone and tendon to prolonged hindlimb suspension in rats

The rat hindlimb suspension model was used to ascertain the importance of ground reaction forces in maintaining bone and tendon homeostasis. Young female Sprague-Dawley rats were randomly assigned to either a suspended or a nonsuspended group. After 28 days, femur bones and patellar tendons were obtained for morphological and biochemical analyses. Prolonged suspension induced a significant change in the geometric configuration of the femur middiaphysis by increasing the minimum diameter (12%) without any significant alterations in cortical area, density, mineral, and collagen concentrations. Femur wet weight, length, DNA, and uronic acid concentrations of suspended animals were not significantly different from bones of nonsuspended rats. However, the collagen and proteoglycan concentrations in patellar tendons of suspended rats were 28% lower than the concentrations of matrix proteins in tissues obtained from nonsuspended animals. These data suggest that elimination of ground reaction forces induces alterations in tendon composition and femur diaphyseal shape by changing regional rates in bone remodeling and localized tendon strain. Therefore it appears that ground reaction forces are an important factor in the maintenance of cortical bone and patellar tendon homeostasis during weight-bearing conditions.     

Biochemical anatomy of human bone: comparative study of compact and spongy bone in femur, rib and iliac crest

Using EDTA extraction procedure, compact and spongy bone from human femur, rib and iliac crest were compared in terms of their content in collagen, sialoprotein, proteoglycan and carbohydrate. The bone matrix sizes displayed significant variations, the femur having the smallest size and iliac crest the largest one. No significant difference in the matrix size has been found between the spongy and compact bone. The EDTA extractability of the spongy bone was higher than that of the compact bone, with femur showing the lowest extractability. The collagen content of the 3 bones studied was similar although the femur had slightly lower values. The sialic and uronic acids and hexose contents were higher in the femur than in the rib and iliac crest. The collagen/hexose, collagen/sialic acid and collagen/uronic acid ratios in the bone matrix were highest in the iliac crest and lowest in the femur, suggesting that alterations in the amounts of bone matrix can affect the mechanical properties of different parts of the bony skeleton and vice versa.     

Lead levels in bone and hair of rats treated with lead acetate

The use of hair and bone as media in evaluation of lead exposure was investigated in this study. For 12–16 wk rats were given tap water containing lead acetate in the following concentrations: 41.7 mg Pb/L, 83.3 mg Pb/L, and 166.6 mg Pb/L. The animals were sacrificed every 4 wk and their tibia bones and hair were collected for determination of lead content. In control animals, the lead level amounted to 1.2 μg/g (range 0.8–1.3 μg/g) and 0.7 μg/g (range 0.4–2.0 μg/g) in bone and hair, respectively. In the treated rats the accumulation of lead in bone and hair occurred in a dose-dependent manner. A positive corelation (r=0.876) was established between the lead levels in bone and hair of the rats. The regression equation was as follows: μg Pb/g bone=0.842×μg Pb/g hair+1.868. After discontinuation of exposure, a significant decrease in the lead content in bone and hair was noticed. About 9 wk after cessation of treatment, the lead content in hair declined to the pre-exposure level, but 64% of the maximal lead concentration did remain in bone. The results of this study indicate that during a continuous exposure the lead level in hair reflects its content in bone. Such phenomena did not occur during the postexposure period.     

Bone growth and calcium balance during simulated weightlessness in the rat

Rats, age 28 days, experiencing tail suspension in modified metabolic cages for 1, 2, and 3 wk were compared with littermate controls. Food and water consumption, urinary and fecal Ca excretion, and serum Ca were measured; hearts, fore- and hindlimb bones, skulls, and mandibles were removed for determination of wet, dry, and ash weights and Ca concentration and for histological examination. Weight gain and Ca intake and excretion were the same for both groups; both displayed net Ca gain. Suspended rats had significantly lower wet, dry, and ash weights of femora and tibiae. Dry weights of the humeri and radii/ulnae were moderately higher, and the skull and mandible dry and ash weights were significantly higher in suspended than in control rats. Cortical thickness of the femur, but not humerus, was less in suspended rats. The data are consistent with the hypothesis that bone growth is influenced by the cardiovascular changes associated with tail suspension.     

Response of the longitudinal growth of cranium and long bones to early weaning in the rabbit

To study the problem whether the growth rates of the cranium and of long bones are different from one another, in 13 age groups of 5 rabbits each three distances of the skull (SSO-SL, SSO-P and N-NSA) and the length of the femur, tibia and calcaneus were measured. Following the early weaning of the rabbits (41/2 weeks), the increase of all measurements was strongly delayed for about one week. Thereafter, during a two weeks' period a typical catch-up growth was observed. From these results the conclusion was drawn that the growth rates of cranium and long bones do not differ from each other, and that a temporary deficiency of food intake affects intramembranous bone growth and cartilaginous growth in a similar way.     

Dietary fat composition modifies the effect of boron on bone characteristics and plasma lipids in rats

Female and male rats weighing about 170 g and 200 g, respectively, were fed diets (approximately 70 microg boron/kg) in a factorial arrangement with supplemental boron at 0 (deficient) and 3 (adequate) mg/kg and canola oil or palm oil at 75 g/kg of diet as variables. After 5 weeks, six females in each treatment were bred. Dams and pups continued on their respective dietary treatments through gestation, lactation and post-weaning. Thirteen weeks after weaning, plasma and bones were collected from 12 male and 12 female offspring in each treatment. Boron supplementation increased femur strength measured by the breaking variable bending moment; tibial calcium and phosphorus concentrations; and plasma alkaline phosphatase. Femur breaking stress was greatest in boron-supplemented rats fed canola oil, and lowest in boron-deprived females fed canola oil; this group also exhibited the lowest femur bending moment. Minerals associated with bone organic matrix, zinc and potassium, were increased by boron supplementation in tibia. Plasma phospholipids were decreased by boron deprivation in females, but not males. Plasma cholesterol was decreased in boron-supplemented males by replacing canola oil with palm oil. The findings suggest that a diet high in omega-3 alpha-linolenic acid promotes femur strength best when the dietary boron is adequate.     

Ytterbium and trace element distribution in brain and organic tissues of offspring rats after prenatal and postnatal exposure to ytterbium

Lanthanides, because of their diversified physical and chemical effects, have been widely used in a number of fields. As a result, more and more lanthanides are entering the environment and eventually accumulating in the human body. Previous studies indicate that the impact of lanthanides on brain function cannot be neglected. Although neurological studies of trace elements are of paramount importance, up to now, little data are provided regarding the status of micronutritional elements in rats after prenatal and long-term exposure to lanthanide. The aim of this study is to determine the ytterbium (Yb) and trace elements distribution in brain and organic tissues of offspring rats after prenatal and long-term exposure to Yb. Wistar rats were exposed to Yb through oral administration at 0,0.1, 2, and 40 mg Yb/kg concentrations from gestation day 0 through 5 mo of age. Concentrations of Yb and other elements (Mg, Ca, Fe, Cu, Mn, and Zn) in the serum, liver, femur, and brain regions (cerebral cortex, hippocampus, cerebellum, and the rest) of offspring rats at the age of 0 d, 25 d, and 5 mo were analyzed by inductively coupled plasma-mass spectrometry. The accumulation of Yb in the brain, liver, and femur is observed; moreover, the levels of Fe, Cu, Mn, Zn, Ca, and Mg in the brain and organic tissues of offspring rats are also altered after Yb exposure. This disturbance of the homeostasis of trace elements might induce adverse effects on normal physiological functions of the brain and other organs.     

Nerve growth factor and norepinephrine concentrations in weight-bearing and non-weight-bearing bones of euthyroid and hyperthyroid rats

Thyroid hormone, nerve growth factor (NGF) and norepinephrine (NE) and weight-bearing affect bone metabolism, yet interactions between these factors and osseous tissue have not been investigated. Therefore, the aims of the study were to measure NGF and NE concentrations in weight-bearing and non-weight-bearing bones from euthyroid (control) and hyperthyroid (HT) rats. Hyperthyroidism was induced by oral intake of triiodothyronine (90 mg/kg/day) for 21 days. Histomorphometry on distal femurs verified significant trabecular bone loss in HT rats compared to euthyroid animals. NGF concentrations were assayed via ELISA, whilst NE concentrations were measured via HPLC and ECD. In euthyroid rats: (i) the concentration of NGF in ribs (914 ng/g) was almost 3-fold greater than in femurs (326 ng/g wet weight of tissue) (ii) the concentrations of NE in ribs (74.7 ng/g) and calvaria (87.4 ng/g) were 2.5-3.5-fold greater than either femurs (24.0 ng/g) or tibiae (30.5 ng/g) and (iii) NE concentrations were comparable between ribs (74.7 ng/g) and calvaria (87.4 ng/g) and similar between tibiae (30.5 ng/g) and femurs (24.0 ng/g). In HT rats: (i) the concentration of NGF in ribs (1802 ng/g) was 4-fold greater than in femurs (402 ng/g) (ii) NE concentrations in ribs (23.3 ng/g) and calvaria (13.6 ng/g) were 4.5-fold and 2.6-fold greater respectively than in tibiae (5.2 ng/g), while ribs had almost a 2-fold higher concentration of NE than calvaria. In HT rats compared to euthyroid animals: (i) NGF concentrations almost doubled in ribs but there was little change in the NGF concentration in femurs (ii) there was a reduction in NE concentrations in calvaria by 84%, in ribs by 69% in tibiae by 83% and 55% in femur (NS). Conclusions: (i) Non-weight-bearing is associated with higher concentrations of NGF and NE than weight-bearing in bones in euthyroid and HT rats; (ii) Hyperthyroidism exerts opposite effects on NGF and NE in bone and (iii) Hyperthyroidism interacts with weight-bearing to determine NGF and NE concentrations in bone. Therefore, the influence of thyroid hormone on NGF and NE in bone may need to be taken into account when considering the action of thyroid hormone on bone in either euthyroid or hyperthyroid states.     

Muscle‐induced loading as an important source of variation in craniofacial skeletal shape

The shape of the craniofacial skeleton is constantly changing through ontogeny and reflects a balance between developmental patterning and mechanical‐load‐induced remodeling. Muscles are a major contributor to producing the mechanical environment that is crucial for “normal” skull development. Here, we use an F₅ hybrid population of Lake Malawi cichlids to characterize the strength and types of associations between craniofacial bones and muscles. We focus on four bones/bone complexes, with different developmental origins, alongside four muscles with distinct functions. We used micro‐computed tomography to extract 3D information on bones and muscles. 3D geometric morphometrics and volumetric measurements were used to characterize bone and muscle shape, respectively. Linear regressions were performed to test for associations between bone shape and muscle volume. We identified three types of associations between muscles and bones: weak, strong direct (i.e., muscles insert directly onto bone), and strong indirect (i.e., bone is influenced by muscles without a direct connection). In addition, we show that although the shape of some bones is relatively robust to muscle‐induced mechanical stimulus, others appear to be highly sensitive to muscular input. Our results imply that the roles for muscular input on skeletal shape extend beyond specific points of origin or insertion and hold significant potential to influence broader patterns of craniofacial geometry. Thus, changes in the loading environment, either as a normal course of ontogeny or if an organism is exposed to a novel environment, may have pronounced effects on skeletal shape via near and far‐ranging effects of muscular loading.     

Attainment of peak bone mass and bone turnover rate in relation to estrous cycle, pregnancy and lactation in colony-bred Sprague-Dawley rats: suitability for studies on pathophysiology of bone and therapeutic measures for its management

Alteration in biochemical markers of bone turnover and bone mineral density (BMD) of whole body and isolated femur and tibia in relation to age, estrous cycle, pregnancy and lactation and suitability of use of rat as model for studies on pathophysiology of bone and therapeutic measures for its management were investigated. Immature rats (1, 1.5 and 2 month of age; weighing, respectively, 39.3 ± 1.0, 67.8 ± 2.4 and 87.2 ± 5.2 g) exhibited high rate of bone turnover, as evidenced by high serum osteocalcin and alkaline phosphatase and urine calcium/creatinine ratio. However, their BMD (whole body or of isolated long bones) was below measurable levels. Marked increase in body weight at 3 months (185.5 ± 5.2 g) was associated with low serum osteocalcin and alkaline phosphatase and urine calcium/creatinine ratio. Biochemical markers and BMD attained at puberty at 3 months were maintained until 36 month of age. No significant change in serum calcium was observed with increasing age or on any of the biomarkers during estrous cycle, and BMD of femur and tibia isolated during proestrus and diestrus stages was almost similar. Onset of pregnancy was associated with significant increase in serum total alkaline phosphatase and osteocalcin levels, but serum calcium, urine calcium/creatinine ratio or BMD of whole body or isolated long bones were not significantly different from that at proestrus stage. No marked change, except increase in body weight (P < 0.05), was also evident in these parameters between days 5 and 19 of pregnancy, irrespective of number of implantations in the uterus. A significant decrease in BMD of isolated femur (neck and mid-shaft regions) was observed on days 5 and 21 of lactation as compared to that during pregnancy or diestrus/proestrus stages of estrous cycle; the decrease being almost similar in females lactating two or six young ones. BMD of isolated tibia (global and region proximal to tibio-fibular separation point), though generally lower than that during cycle and pregnancy, was statistically non-significant. However, clear evidence of occurrence of osteoporosis during lactation, with decrease in BMD of >2.5 × S.D. in isolated femur (global, neck and mid-shaft) as well as tibia (global) was observed only when BMD data was analysed on T-/Z-score basis. Serum biochemical markers of bone turnover, too, were significantly increased in comparison to cyclic rats. Findings demonstrate marked increase in body weight and bone turnover during first 3 months of age, direct correlation between peak bone mass and onset of puberty at 3 months of age and increase in bone resorption rate during lactation. Finding of the study while might suggests possible use of rat as useful model for studies on bone turnover rate during lactation and post-weaning periods and extrapolation of the result to the human situation, but not in relation to ageing.     

Bone tissue changes in rats during prolonged restriction of motor activity

The objective of this investigation was to measure the effect of prolonged restriction of motor activity (hypokinesia) of rats on the mass, density, mineral composition, reconstruction parameters and elemental composition of their bone tissue. The studies were done during 90 days of hypokinesia (HK) on 90 male Wistar rats equally divided into two groups: (1) vivarium control rats (VCR) and (2) hypokinetic rats (HKR). For the simulation of the hypokinetic effect the HKR group was kept for 90 days in small individual cages made of wood that restricted the movements of rats in all directions without hindering food and water intakes. During the prehypokinetic period of 15 days and during the hypokinetic period of 90 days bone mass, bone density, bone calcium and phosphorus concentrations, bone reconstruction parameters and elemental composition of bones were determined. During the same periods food intake and body weight losses were also measured. In the HKR group signs of osteoporosis in the spongy structures of the tubular bones were observed; they also showed significant decrease in rat femur weight, and in cross section of the rat femur, and in mineral concentrations of the femoral head when compared with the VCR group. The HKR group also show a significant decrease in food intake and body weight when compared with the VCR group. The corresponding parameters did not change significantly in the VCR group when compared with the baseline control values. It was concluded that prolonged exposure to HK induced osteoporosis and structural changes in bones. This apparently occurred due to inhibition of bone tissue formation in the HKR group.     

The accumulation,distribution, and toxicological effects of dietary arsenic exposure in lake whitefish (Coregonus clupeaformis) and lake trout (Salvelinus namaycush)

A 20-day experiment was conducted to compare the accumulation, distribution, and toxicological effects of dietary As, as arsenate, in lake whitefish (LWF, Coregonusclupeaformis) and lake trout (LT, Salvelinus namaycush). Results of this experiment were used to design an experiment of longer duration in which one of the fish species was selected and exposed three times per week to lower dietary As doses. In the present study each treatment group was exposed to a combination of one of three doses of As (0, 100, or 1000 μg As/g) and one of two types of diet, no brine shrimp (NS) or with brine shrimp (WS) for a total of eight dosing events. Brine shrimp were added to determine whether their presence enhanced consumption of As-contaminated food. Modified feeding behavior occurred in both fish species fed As contaminated diets, with the exception of the 100 μg As/g NS food. Brine shrimp addition did not affect feed consumption of the As contaminated diets. Significant As accumulation occurred in stomach, pyloric caeca, intestine, liver, kidney, and gallbladder, but not in bile or muscle. As exposure did not have a significant effect on hepatic and renal metallothionein concentrations. Concentrations of lipid peroxides were only significantly elevated in the plasma of LT fed the 1000 μg As/g WS food. Liver somatic indices decreased significantly in both species, whereas hematological parameters were not affected in either species. Histological lesions occurred in gallbladder, liver, kidney, pyloric caeca and intestine from LWF. These lesions were not observed in LT; however, gallbladders were not examined in this species. Weight gain was lower in both species fed As contaminated diets, however, condition factors were not affected.     

Age and sex bias in the reconstruction of past population structures

Palaeodemographical studies are founded on the assumption that the sex and age distribution of the skeletal sample reflects the constitution of the original population. It is becoming increasingly clear, however, that the type and amount of information that may be derived from osteoarchaeological collections are related to the state of preservation of remains. This work proposes a new method to evaluate bone preservation, to identify age and sex biases in the preservation of human skeletal remains, and to assess whether differences in preservation patterns are more dependent on factors intrinsic or extrinsic to anatomical features of human bones. Three osteological collections and over 600 skeletons were observed. The state of preservation of human bones was assessed using three preservation indexes: the anatomical preservation index (API), the bone representation index (BRI), and the qualitative bone index (QBI). The results suggest that subadult skeletons are generally more poorly preserved and with bones less well-represented than adult skeletons. Among subadults, female and male skeletons have different patterns of preservation according to their age. This pattern of preservation depends on intrinsic anatomical properties of bones themselves, while external factors can only increase these differences in the state of preservation and representation of osseous remains. It is concluded from this that failure to recognize these differences may lead to misleading interpretations of paleodemography of past human populations.     

Determination of Arsenic Scalp Hair of Pakistani Children and Drinking Water for Environmental Risk Assessment

This cross-sectional study measured the arsenic level in scalp hair samples of children from two age groups exposed to contaminated underground water in Pakistan. The As concentrations in water and scalp hair samples were analyzed by electrothermal atomic absorption spectrometry. The studied areas were divided into three regions based on concentration of As in water and scalp hair of children who had been exposed to different levels of As through drinking water. The average As concentrations in underground water samples of sub-districts Faiz Ganj, Thari Mirwah, and Gambat were observed to be 15.2, 28.5, and 98.3 μg/L, respectively, which were marked as less, medium, and highly contaminated areas, respectively. The proportion of the children with lower body mass index significantly increased with increasing As exposure level; the dose–response relationship was consistently observed among the subgroups. The range of As concentrations in scalp hair samples of children of age 1–5 and 6–10 years was 0.21–3.88 and 0.32–3.63 μg/g, respectively. Thus, it is likely that children in our study areas are chronically exposed to As through drinking groundwater, suggesting that there is an urgent need to take immediate solution, especially in the Gambat sub-district.