Does high serum iron level induce low bone mass in sickle cell anemia ?

Iron overload is quite common in patients suffering from hemoglobinopathies causing arthropathies, endocrinal affection and neuropathies. Recently low bone mass was added to the list of complications. This study is conducted to find any correlation between serum iron level and low bone mass in sickle cell anemia (SCA). Patients ≥18 years of age with sickle cell anemia, who attended outpatient clinics or admitted to King Fahd University Hospital, Al Khobar, Saudi Arabia,between 1st September 2006 and August 2007 were the subjects of this study. Patients age and sex were documented and body mass index was calculated. Apart from routine hematological tests, serum ferritin, serum Iron level, total estradiol, testosterone level was done. Bone mineral density measurement was done using dual energy X-ray absorptiometry (DEXA) at upper femur and lumbar spine. The data of 100 patients was analyzed, 48 males and 52 females. The mean age was 27.5 ± 6.1 years. In 64 patients (32 males and 32 females) serum iron level was 319.35 μg/dl and the mean serum ferritin level in males and females was within the normal range. Sixty-eight percent of females and 71.8% of males patients in whom serum iron was high had lower bone mass P = < 0.001. Our study shows that SCA patients in whom serum iron level was higher than normal effected bone mass. Further studies are needed to confirm this as a cause of osteoporosis in SCA patients.     

DEXA对骨髓炎骨缺损治疗中骨痂密度的评价

目的：探讨DEXA对骨髓炎骨缺损治疗中骨痂密度的评价及意义。方法：严格按照纳入排除标准,选取21例骨髓炎清创后伴大段皮质骨缺损一期植骨的病人。术后4,6,8,10个月后对骨折端骨痂行双能X线骨密度仪检测,并进行X摄片以及Enneking评分,从而明确植骨区愈合骨痂的密度变化趋势,骨愈合情况以及症状改善情况。结果：（1）X线摄片结果显示：4个月后：骨缺损区依然清晰可见,内有少量稀疏骨痂通过,少量外骨痂形成。6个月后：植骨区内骨痂含量明显增多,且外骨痂膨大。8个月：缺损区模糊,有较致密骨痂生成,且外骨痂逐渐减少。10个月：植骨区骨痂更加致密,且部份髓腔再通。（2）Enneking评分：患者术后第10个月功能恢复情况评估正常功能20例,20分以下的患者1例。（3）BMD测定：骨折端的骨密度及骨密度比率随时间延长而增加,植骨10个月后患侧的骨密度已可基本上达到正常对照侧的骨密度水平。结论：双能X线骨密度测量从一定程度上反映出骨痂的力学强度特性。在感染性骨缺损治疗中可以作为检测植骨区的恢复情况的参考。     

Differences in zinc status between patients with osteoarthritis and osteoporosis

Zinc has been suggested to play an important role in the development of osteoporosis, whereas the influence of zinc on osteoarthritis has attracted much less attention. The aim of the study was to investigate and compare the zinc status and bone turnover, density, and biomechanical properties of osteoarthritic and osteoporotic patients. The study comprised 40 women who underwent hip replacement due to osteoarthritis or osteoporosis. Serum and urine zinc content, and bone resorption markers and serum bone formation markers were determined. The unaffected hip and the exarticulated affected femoral head underwent DEXA scanning. Bone biopsies were obtained from the femoral heads and the biomechanical properties were determined. The biopsies were ashed and the bone zinc content was ascertained. Osteoarthritic patients had significantly higher serum zinc concentrations and lower urine zinc concentrations than osteoporotic patients, whereas the bone zinc content did not differ. The zinc status was not found to be a predictor for the bone strength. In conclusion, the finding that the zinc status of osteoporotic patients is significantly different from that of osteoartritic patients is new and supports the view that osteoporosis and osteoarthritis rarely occur in the same individual.     

Iron restriction negatively affects bone in female rats and mineralization of hFOB osteoblast cells

We previously reported that severe iron deficiency negatively affects bone microarchitecture. Here we determined whether marginal iron restriction that reflects some human consumption patterns could have similar consequences. Thirty-two weanling female rats were randomly divided into four groups and fed the following diets for 10 weeks: (i) iron-adequate, calcium-adequate (FeA:CaA), (ii) calcium-restricted (FeA:CaR), (iii) iron-restricted (FeR:CaA), and (iv) both calcium- and iron-restricted (FeR:CaR) diets. DEXA analysis revealed that CaR decreased bone mineral density (BMD), and FeR decreased whole-body bone mineral content (BMC). Iron-restricted and calcium-restricted groups had lower BMD than did their adequate counterparts. All treatment-restricted groups had lower BMD in the fourth lumbar (L-4) vertebrae than the FeA:CaA group. Vertebrae BMD was lower in all treatment groups compared to the control group, and for BMC, the CaR groups were lower than the CaA groups and the FeR groups were lower that the FeA groups, and BMC were lower in iron- and calcium-restricted groups. The microarchitecture of the L-4 vertebrae was compromised in FeA:CaR, FeR:CaA, and FeR:CaR: (i) the connectivity density was reduced by FeR and by CaR; and (ii) trabecular number was decreased and trabecular separation was increased by FeR. Cortical thickness of the femur was reduced by both FeR and CaR. Finite element analysis revealed that L-4 vertebrae from the FeR:CaA group had greater internal stress with an applied force than the FeA:CaA group and, thus, would be more likely to break. Chelation of iron in cultured osteoblast cells impaired mineralization but had no impact upon Type I collagen deposition. Iron depletion, similar to that occurring among some human populations, reduced bone strength and microarchitecture based on the in vivo and in vitro results reported here. Impaired mineralization with iron depletion appears to be a possible mechanism for the observed bone abnormalities.     

Phytase supplementation increases bone mineral density,lean body mass and voluntary physical activity in rats fed a low-zinc diet

Phytic acid forms insoluble complexes with nutritionally essential minerals, including zinc (Zn). Animal studies show that addition of microbial phytase (P) to low-Zn diets improves Zn status and bone strength. The present study determined the effects of phytase supplementation on bone mineral density (BMD), body composition and voluntary running activity of male rats fed a high phytic acid, low-Zn diet. In a factorial design, rats were assigned to ZnLO (5 mg/kg diet), ZnLO+P (ZnLO diet with 1500 U phytase/kg) or ZnAD (30 mg/kg diet) groups and were divided into voluntary exercise (EX) or sedentary (SED) groups, for 9 weeks. SED rats were significantly heavier from the second week, and no catch-up growth occurred in EX rats. Feed intakes were not different between groups throughout the study. ZnLO animals had decreased food efficiency ratios compared to both phytase-supplemented (ZnLO+P) and Zn-adequate (ZnAD) animals (P<.01 compared to ZnLO). The ZnLO+P and ZnAD rats ran 56–75 km more total distance than ZnLO rats (P<.05), with the ZnLO+P rats running more kilometers per week than the ZnLO rats by Week 6. In vivo DEXA analyses indicate that rats fed phytase-supplemented diets had higher lean body mass (LBM) than those fed ZnLO diets; and that rats fed the Zn-adequate diets had the highest LBM. Body fat (%) was significantly lower in EX rats and was both Zn- and phytase insensitive. Rats fed phytase-supplemented diets had higher bone mineral content (BMC), bone area (BA) and BMD than rats fed ZnLO diets; and in rats fed ZnAD diets these indices were the highest. The dietary effects on BMC, BA and BMD were independent of activity level.We conclude that consuming supplemental dietary phytase or dietary Zn additively enhances Zn status to increase BMD, LBM and voluntary physical activity in rats fed a low-Zn diet. While the findings confirm that bone health is vulnerable to disruption by moderate Zn deficiency in rats, this new data suggests that if dietary Zn is limiting, supplemental phytase may have beneficial effects on LBM and performance activity.     

Bone mineral density, osteopenia, and osteoporosis in the rhesus macaques of Cayo Santiago

This cross-sectional study investigates metabolic bone disease and the relationship between age and bone mineral density (BMD) in males and females of a large, well-documented skeletal population of free-ranging rhesus monkeys (Macaca mulatta), from the Caribbean Primate Research Center Museum collection from Cayo Santiago, Puerto Rico. The sample consists of 254 individuals aged 1.0-20+ years. The data consist of measurements of bone mineral content and bone mineral density, obtained from dual-energy X-ray absorptiometry (DEXA), of the last lumbar vertebra from each monkey. The pattern of BMD differs between male and female rhesus macaques. Females exhibit an initial increase in BMD with age, with peak bone density occurring around age 9.5 years, and remaining constant until 17.2 years, after which there is a steady decline in BMD. Males acquire bone mass at a faster rate, and attain a higher peak BMD at an earlier age than do females, at around 7 years of age, and BMD remains relatively constant between ages 7-18.5 years. After age 7 there is no apparent effect of age on BMD in the males of this sample; males older than 18.5 years were excluded due to the presence of vertebral osteophytosis, which interferes with DEXA. The combined frequency of osteopenia and osteoporosis in this population is 12.4%. BMD values of monkeys with vertebral wedge fractures are generally higher than those of virtually all of the nonfractured osteopenic/osteoporotic individuals, thus supporting the view that BMD as measured by DEXA is a useful but imperfect predictor of fracture risk, and that low BMD may not always precede fractures in vertebral bones. Other factors such as bone quality (i.e., trabecular connectivity) should also be considered. The skeletal integrity of a vertebra may be compromised by the loss of key trabeculae, resulting in structural failure, but the spine may still show a BMD value within normal limits, or within the range of osteopenia.     

Failure to respond to interferon-α 2a therapy is associated with increased hepatic iron levels in patients with chronic hepatitis C

Recent reports suggest the hepatic iron concentration (HIC) may influence the activity of hepatitis and the response to interferon (IFN) therapy in patients with chronic hepatitis C (CH-C). We have evaluated iron status in 28 patients with CH-C and determined if pretreatment iron status can predict the response to IFN-α therapy in these patients. Increased serum iron, transferrin saturation, and ferritin levels were observed in 3 (11%), 11 (39%), and 5 (18%) patients, respectively. Hepatic iron deposits were histologically detected in 17 (61%) patients, and 14 of them had stainable hepatocytic iron. However, all HIC values were within the normal range (203–1279 μg/g). Seven of 17 patients treated with IFN-α for 6 mo had normalization of serum transaminases and disappearance of serum HCV-RNA (responders). Nonresponders had a significantly higher median HIC compared with responders (710 vs 343 μg/g, respectively;p < 0.05). There was no significant difference in other pretreatment iron parameters, serum HCV-RNA level, or HCV-genotype between responders and nonresponders. In conclusion, mild hepatic iron accumulation occurs in patients with CH-C. Increased hepatic iron stores are associated with poor response to IFN therapy. Pretreatment HIC may be an additional host-specific parameter with a predictive value for responsiveness to IFN therapy, in addition to well-known predictive viral factors.     

Higher Levels of Osteoprotegerin and Immune Activation/Immunosenescence Markers Are Correlated with Concomitant Bone and Endovascular Damage in HIV-Suppressed Patients

HIV-infected patients appear to have a significantly greater risk of non-AIDS comorbidities such as osteoporosis and atherosclerosis. Subjects with osteoporosis are at a higher risk of developing cardiovascular disease than those with normal bone mass, therefore a possible relation between these two conditions can be hypothesized. In the setting of HIV infection, several factors might contribute to bone disease and endothelial dysfunction. The aim of our study was to evaluate the relationship between bone and cardiovascular disease and to investigate the role of traditional factors, T-cell phenotype and osteoprotegerin in HIV positive subjects on effective antiretroviral therapy. We included 94 HIV positive subjects on antiretroviral therapy with virological suppression and 41 healthy subjects matched for age and gender as a control group. Carotid-Intima Media Thickness (c-IMT) and bone mineral density (BMD) were performed by ultrasound and DEXA, respectively. CD4⁺/CD8⁺ T-cell activation, senescence and osteoprotegerin plasma levels were measured by flow-cytometry and ELISA, respectively. Among HIV positive patients, 56.4% had osteopenia/osteoporosis and 45.7% had pathological c-IMT (>0.9mm). Subjects with pathological c-IMT and BMD exhibited higher CD4⁺ and CD8⁺ activated, CD8⁺ senescent and osteoprotegerin than subjects with normal c-IMT and BMD. HIV positive subjects with osteopenia/osteoporosis had higher c-IMT than subjects with normal BMD, and linear regression analysis showed a negative correlation between BMD and c-IMT. Several factors are implicated in the pathogenesis of non-AIDS comorbidities in HIV positive patients. Osteoprotegerin together with inflammation and immunosenescence in HIV positive patients could affect bone and vascular system and could be considered as a possible common link between these two diseases.     

Correlation between pre-operative periprosthetic bone density and post-operative bone loss in THA can be explained by strain-adaptive remodelling.

Periprosthetic adaptive bone remodelling after total hip arthroplasty can be simulated in computer models, combining bone remodelling theory with finite element analysis. Patient specific three-dimensional finite element models of retrieved bone specimens from an earlier bone densitometry (DEXA) study were constructed and bone remodelling simulations performed. Results of the simulations were analysed both qualitatively and quantitatively. Patterns of predicted bone loss corresponded very well with the DEXA measurements on the retrievals. The amount of predicted bone loss, measured quantitatively by simulating DEXA on finite element models, was found to be inversely correlated with the initial bone mineral content. It was concluded that the same clinically observed correlation can therefore be explained by mechanically induced remodelling. This finding extends the applicability of numerical pre-clinical testing to the analysis of interaction between implant design and initial state of the bone.     

Bone mass in young patients with type I diabetes

We measured bone mineral content (BMC) with single photon absorptiometry in two groups of young patients with type I diabetes: the first group (prospective study) consists of 48 patients followed from onset to the third year of diabetes and the second group (cross-sectional study) consists of 66 long-term diabetics. Bone mineral content at onset of disease was lower than normal in only two cases. After 3 years of diabetes no male revealed BMC below the normal range but two females (6.6%) had low BMC values. In our cross-sectional study we found a BMC reduction in 12% of the cases. We did not find a relationship between bone deficit and duration of diabetes, or bone mass values and HbA1.     

Relationships between bone and skin atrophies during aging.

Bone mineral density (BMD) was measured in 133 female subjects (age: 61.7 +/- 16.3 years) by dual energy X-ray absorptiometry (DEXA). Vertebral bone mineral density (BMD; L1-L4) and BMD of the whole upper femoral extremity were taken into account. In addition, skinfold thickness was measured with a callipers on the dorsum of the nondominant hand. A significant negative correlation was found between skinfold thickness and age (r = -0.623, p less than 0.0001). Both vertebral and femoral BMD decreased with age and the slopes were similar to those observed by other authors. Skinfold thickness was significantly correlated with vertebral (r = 0.364, p less than 0.0001) and femoral BMD (r = 0.486, p less than 0.0001). Skin and bone are connective tissues whose extracellular matrix mainly contains type I collagen. It is postulated that age-related skin atrophy and bone atrophy have a common genetic mechanism. Skinfold thickness measurement may help in defining the women at risk for osteoporotic bone fractures who should be referred for a DEXA examination.     

Effect of misoprostol on bone mineral density in women with postmenopausal osteoporosis

OBJECTIVE: To evaluate the effect of misoprostol on bone mineral density in postmenopausal women. MATERIALS AND METHODS: The study was performed in a randomized controlled prospective manner in 90 women with menopause at Süleymaniye Maternity and Women's Diseases Teaching and Research Hospital between January and December 2003. Cases were divided into three groups each consisting of 30 women who were in menopause for at least 1 year and had t-scores less than -1 by dual energy X-ray densitometry (DEXA). Group I was treated with misoprostol and calcium, Group II received tibolone and calcium and Group III was given calcium only and considered as control group. In all patients, bone mineral density in L1-L4 vertebrae, femur neck and Ward triangle were measured by DEXA and t and z scores were calculated. RESULTS: All groups were similar demographically. Bone mineral density in L1-L4 vertebrae, femur neck and Ward triangle in the group treated with misoprostol, increased by 5, 8.1 and 3.6%, respectively. In the tibolone group, bone mineral density in L1-L4 vertebrae, femur neck and Ward triangle increased by 8.3, 5.3 and 7.8%, respectively. There was not a significant difference in t and z-scores and bone mineral density measurements between misoprostol and tibolon groups. CONCLUSION: Misoprostol may be an alternative treatment for patients with osteopenia and osteoporosis who are not suitable for hormone replacement therapy.     

Long-term experiment to study the development, interaction, and influencing factors of DEXA parameters

Dual-energy X-ray absorption (DEXA) is commonly used to measure bone mineral density (BMD), bone mineral content (BMC), and body composition data (fat mass and lean mass) for phenotype assessment in mice. We were interested in the long-term development of BMD, BMC, lean mass, and fat mass of mice, also taking into account sex and genetic background. The dataset was used to analyze correlations among the different parameters. We analyzed males and females from inbred strains C3HeB/FeJ and C57BL/6J, starting from 42 until 528 days of age. To evaluate the effect of husbandry systems, we repeated a part of the study in a second facility with a different caging system. We also assessed different DEXA settings and repeatability of the scans. The results of this study were used to draw conclusions for the use of DEXA analysis in mouse phenotyping approaches.     

Different involutionary changes in bone mineral density with age in three skeletal sites in healthy Polish women

The aim of the study was to estimate the differences in bone mineral density (BMD) at three skeletal sites, with regard to age and menopausal status.The study was conducted between 2001 and 2006 in the Polish city of Wroc?aw and the sample was comprised of 440 healthy female inhabitants aged 40–88 years. The measurements of bone mineral density were taken at three sites: femoral neck, Ward's triangle and trochanter major. Two bone mineral density characteristics were used in further analysis: absolute measure of bone mineral density (BMD) expressed in g/(100 mm)², and % of BMD of the peak value calculated for young adults (20–45, USA reference population). Pre- and postmenopausal status was defined according to occurrence of menstruation within the last 60 days.The changes in bone mineral density with age showed significantly different patterns in different skeletal sites. While the decrease in bone mineral density in the femoral neck and Ward's triangle were parallel and gradual, the changes in trochanter major were very small and between the age groups 51–55 and 71–75, nearly unnoticeable. A comparison between pre- and postmenopausal women aged 46–55, showed a significant effect of menopausal status. The average bone mineral densities in the three skeletal sites were higher in premenopausal than in postmenopausal women. The highest value of bone mineral density was found in the femoral neck, significantly lower in Ward's triangle, and a little lower (non-significantly) in the trochanter major than in the Ward's triangle. Postmenopausal women had a little higher BMD value in the trochanter major than in the Ward's triangle site.     

Mineral content of calcified tissues in cystic fibrosis mice

Although abnormal hard tissue mineralization is a recognized complication of cystic fibrosis (CF), the pathogenesis leading from the defective cystic fibrosis transmembrane conductance regulator (CFTR) protein is poorly understood. We hypothesized that CFTR plays a direct role in the mineralization of bone and teeth and tested the hypothesis using CF mouse models [CFTR(−) mice]. In vivo measurements by dual-emission X-ray absorpitometry (DEXA) indicated that bone mineral density (BMD) was reduced in CF mice as compared to gender-matched littermates. However, no change was evident after correction of BMD for the covariant of body weight. The latter finding was confirmed in isolated femurs and nasal bones by standard dry-ashing and instrumental neutron activation analysis (INAA). INAA of the continuously growing hypsodont incisor teeth from CFTR(−) mice revealed reduced Ca and normal P in the enamel layer—a finding consistent with changes in the deciduous teeth of CF children. Interestingly, enamel fluoride was increased in the CFTR(−) incisors and may associate with abnormal enamel crystallite formation. The iron content of the incisor enamel was reduced, explaining the loss of yellow pigmentation in CFTR(−) incisors. In contrast to the incisors, the mineral content of the slow-growing brachydont molar teeth was not different between CFTR(−) and CFTR(+) mice. It was concluded that CFTR does not play a direct role in the mineralization of bones or brachydont teeth in mice. Functional CFTR is apparently required for normal mineralization of the hypsodont incisors. However, multiple changes in the mineral composition of the CF incisors suggest an indirect role for CFTR, perhaps by maintaining a normal salivary environment for continuous tooth eruption. Preliminary reports published in Pediatric Pulmonology, 14, 253A (1997) and 15, 253A (1998).     

Elements in autopsy liver tissue samples from Greenlandic Inuit and Danes. II. Iron measured by X-ray fluorescence spectrometry.

The purpose of this study was to measure the content of iron (Fe) in liver tissue samples from urbanized Greenlandic Inuit using X-ray fluorescence spectrometry, and compare the results with those obtained in liver tissue samples from urbanized Danes. Normal liver tissue samples were obtained at autopsy from 50 Greenlandic Inuit (27 men, 23 women) with a median age of 61 years (range 23-83) and from 72 Danes (42 men, 30 women) with a median age of 62 years (range 15-87). In the entire series, there was no significant difference between liver iron in Inuit compared with Danes. Likewise, there was no significant gender difference concerning liver iron content, either in Inuit or in Danes. The median iron content (with 5-95 percentile) in Inuit was 17.23 mmol/kg dry liver (5.80-91.80) and in Danes 16.51 mmol/kg dry liver (7.83-39.05). However, when stratified according to age, a trend was revealed showing that Inuit men and women < or = 50 years had a lower liver iron content than Danes (p = 0.05 and p = 0.08) whereas Inuit men and women > 50 years had a higher liver iron content than Danes (p = 0.18 and p = 0.02). There was a significant correlation between liver iron content and age in both Inuit men (rs = 0.49, p = 0.01) and in women (rs = 0.64, p = 0.003), but not in Danes. In Inuit, the median hepatic iron index (liver iron content divided by age) was 0.33 in men and 0.32 in women. The median estimated iron content in the whole liver was 6.54 mmol (365 mg) in Inuit men and 5.41 mmol (302 mg) in Inuit women (p = 0.6). There was no correlation between hepatic iron index and age. In Danes, the median hepatic iron index was 0.46 in men and 0.29 in women (p = 0.01). There was a significant inverse correlation between hepatic iron index and age in the two genders and in the entire series (rs = -0.71, p = 0.0001). The results indicate that young and middle-aged urbanized Inuit have slightly smaller iron stores than urbanized Danes, whereas elderly Inuit have higher iron stores than Danes. In Danes, iron stores plateau at 30 to 40 years of age in men and some years after the menopause in women. In Inuit, iron stores continue to increase in old age, probably to due a lifelong dietary intake of haem iron.     

Iron stores in essential thrombocythaemia. A study of 26 patients

The iron status of 26 patients with essential thrombocythaemia (ET) was evaluated at diagnosis by means of bone marrow iron and blood studies, including serum ferritin determination. Nine patients were males, 17 females, and the mean age was 53 years (range 7-81). A decreased or absent iron level by semiquantitative estimation on bone marrow smears was observed in 77% of patients, and 81% had a low sideroblast score. Such a marrow pattern of iron depletion was equally distributed between both sexes. Contrasting with this, normal Hb, MCV, serum iron and serum ferritin were registered in the majority of cases. According to these results, absent or decreased marrow iron would be a common feature in ET, generally not reflecting true iron deficiency, as it occurs in the remaining chronic myeloproliferative disorders. Thus, in patients in whom ET is suspected, the diagnostic criterion of ruling out iron deficiency would be better served by serum ferritin measurement than by bone marrow iron estimation.     

Content and deposition of major mineral elements in different tissues and empty body of growing bulls of the german simmental breed

54 bulls of the German Simmental breed were fed either on a high energy level (maize silage ad libitum and 1.8 kg concentrate) or on a low energy level (maize silage restrictively and 1.0 kg concentrate). In dependence on feeding intensity a mean daily weight gain of 870 or 1210 g was obtained. Animals were slaughtered with a live mass of 200 kg, 350 kg, 500 kg, 575 kg and 650 kg. Empty body was divided into 13 cuts and afterwards separated into lean, bone and adipose tissues and tendons. Major mineral element content was determined in these tissues as well as in the noncarcass parts.

In the lean tissue the mean content (200 kg) of 0.3 g calcium, 10 g phosphorus, 1 g magnesium, 2.3 g sodium and 14.8 g potassium/kg dry matter decreased slightly with rising live mass (200–650 kg). The contents of major mineral elements were much higher in bone tissue. For the fattening period from 200 to 650 kg of live mass mean contents of 151.5 g calcium, 71.3 g phosphorus, 3.2 g magnesium, 5.1 g sodium and 1.1 g potassium per kg DM were analysed. Mineral element content of bone tissue increased with rising live mass as well as animals on low feeding intensity showed a higher mineral content than on high energy level. In all, major mineral element content in fat tissue was very low. In noncarcass parts head and legs calcium and phosphorus had analogous to bone tissue the highest concentration. Hide showed a high content of sodium, whereas organs and digestive tract had a high content of potassium and phosphorus. Total mass of major mineral elements in the different tissues increased above all in the fattening period of 200 to 350 kg. In carcass as well as in empty body, mass of calcium and phosphorus was much higher than magnesium, sodium and potassium. Also animals on low feeding intensity showed a higher mass of major mineral elements in carcass and empty body than animals on high energy feeding intensity. The intensively fed bulls had a mean deposition of 12.7 g calcium, 6.9 g phosphorus, 0.37 g magnesium, 1.2 g sodium and 2.1 potassium per 1000 g of empty body weight gain, whereas restrictively fed bulls deposited in average 15.0 g calcium, 7.8 g phosphorus, 0.4 g magnesium, 1.2 g sodium and 2.4 g potassium per 1000 g of empty body weight gain.     

Selenium, iron, copper, and zinc levels and copper-to-zinc ratios in serum of patients at different stages of viral hepatic diseases

Viral hepatic diseases, especially those induced by the hepatitis B virus, can progress into more serious pathological outcomes and eventually to hepatocellular carcinoma. A growing body of evidence indicates that many trace elements play important roles in a number of carcinogenic processes that proceed through various mechanisms. To examine the status of trace elements during the development of hepatic carcinoma, we determined the selenium, iron, copper, and zinc levels and copper-to-zinc ratios in the serum of patients at different stages of viral hepatic disease. We observed significant changes in the selenium, iron copper, and zinc levels in the serum of patients having hepatocellular carcinoma, relative to those of healthy controls (p<0.05). The mean serum copper level in patients with hepatocellular carcinoma was significantly higher than that of the control group. In contrast, the mean selenium, iron, and zinc levels in patients having hepatocellular carcinoma were significantly lower than those of the control group. In addition, the mean zinc level in the serum of patients with hepatic cirrhosis was significantly lower than that of the control group (p<0.05). Moreover, we found markedly elevated Cu: Zn ratios (p<0.05) in patients having hepatic cirrhosis or hepatocellular carcinoma. Our findings imply that the levels of some trace elements, such as selenium, iron, copper, and zinc, and Cu:Zn ratios, might serve as biomarkers for the increased severity of viral hepatic damage.     

绝经后健康妇女甲状旁腺激素基因多态性与骨密度的关系

利用限制性片段长度多态性分析（RFLP）研究北京地区绝经后妇女甲状旁腺激素（PTH）基因多态性与骨密度的关系。筛选健康、无亲缘关系的绝经后妇女185例, 应用双能X射线骨密度仪（DEXA）检测腰椎等部位的骨密度,用PCR-RFLP方法检测绝经后妇女的PTH基因型。绝经后健康妇女中bb、Bb、BB三种基因型的分布频率分别为7.56%、28.11%和64.32%。方差分析显示前臂部位骨密度与PTH基因相关。除华氏三角区外,BB基因型各部位的骨密度值均高于Bb、bb基因型。Logistic回归分析结果显示,bb基因型组骨质疏松与正常妇女存在显著差异（P＜0.001）。 PTH基因中B基因型可能对维持骨量具有一定的作用。