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.     

Daily magnesium supplementation on serum and urinary magnesium changes in rats during prolonged restriction of motor activity

The objective of this investigation was to determine whether a plentiful magnesium (Mg²⁺) supplementation might be used to normalize or prevent Mg deficiency. This is manifested by increased rather than decreased serum Mg²⁺ concentration as is observed during prolonged hospitalization, which is developed during prolonged hypokinesia (HK) (decreased motor activity). Eighty male Wistar rats with an initial body weight of 370–390 g were used to perform the studies: They were equally divided into four groups:

1. Unsupplemented control animals (UCA);
2. Supplemented control animals (SCA);
3. Unsupplemented hypokinetic animals (UHA); and
4. Supplemented hypokinetic animals (SHA).

For the simulation of the hypokinetic effect, the hypokinetic animals were kept in small individual cages made of wood, which restricted their movements in all directions without hindering food and water intake. The control and hypokinetic supplemental animals receive 0.9 mg/mL Mg sulfate daily with their drinking water. Prior to and during the experimental period, urinary excretions of Mg, calcium, and phosphate along with their concentrations in serum, water intake, and urine excretion, and body weight were determined in the control and hypokinetic animals. In the supplemental and unsupplemental hypokinetic rats, urinary excretions and serum concentrations of electrolytes increased significantly, whereas serum concentration and urinary excretion thereof remained unchanged in the supplemented and unsupplemented control animals. It was concluded that a daily intake of large amounts of Mg supplementation cannot be used to prevent or normalize Mg deficiency in rats during prolonged exposure to HK.     

Daily zinc supplementation effect on zinc deficiency in rats during prolonged restriction of motor activity

The objective of this investigation was to evaluate the effect of 47 mg zinc supplementation on deficiency of zinc in rats during 98 d of restriction of motor activity (hypokinesia), which appeared by higher plasma zinc concentration. One Hundred 13-week-old Sprague-Dawley male rats weighing 360–390 g were used to perform the studies: They were equally divided into four groups: 1. Unsupplemented control animals (UCA); 2. Unsupplemented hypokinetic animals (UHA); 3. Supplemented control animals (SCA); and 4. Supplemented hypokinetic animals (SHA). For the simulation of the effect of hypokinesia (HK), the UHA and SHA were kept in small individual cages made of wood, which restricted their movements in all directions without hindering food and water intake. The SCA and SHA received daily with their food an additional amount of zinc. Before and during the experimental period of 98 d, plasma, urinary and fecal zinc, balance of zinc, food intake, and body weight were determined at different intervals. In the SHA and UHA, the concentration of zinc in plasma, and the elimination of zinc in urine and feces increased significantly when compared with the SCA and UCA, whereas the balance of zinc was negative. The body weight and food intake decreased significantly in the SHA and UHA when compared with the SCA and UCA. The increased plasma concentration of zinc in both the SHA and UHA groups was in contrast to the observed hypozincnemia during prolonged immobilization as during prolonged hospitalization. This reaction suggests that there may be some other mechanisms that are affecting the process of control and regulation of zinc metabolism during prolonged HK. It was concluded that exposure to prolonged restriction of motor activity of rats induces significant increases in plasma concentration, fecal and urinary elimination of zinc in the presence of negative zinc balance and regardless the daily intake of large amounts of zinc with their food, leading to zinc deficiency.     

SASCUBE: An Updated Method of Cubes for Calculation of the Intensity of X-Ray Scattering by Biopolymers in Solution

Biophysics - Abstract—This work describes an updated method of cubes, which allows calculation of the SAS curves for biopolymers in solution on the basis of the coordinates of their atoms...     

Magnesium loading effect on magnesium deficiency in endurance-trained subjects during prolonged restriction of muscular activity

The aim of this study was to evaluate the effect of magnesium (Mg) loading (10.0 mg Mg/kg body wt) and daily Mg supplements (5.0 mg Mg/kg body wt) on Mg deficiency shown by increased and not by decreased serum Mg concentration during hypokinesia (decreased km number/d). The studies were done during 30 d of prehypokinesia and 364 d of hypokinesia (HK) periods. Forty endurance-trained volunteers aged 22–26 yr with a peak VO2 max of 66.3 mL·kg⁻¹ min⁻¹ and with an average 15.0 km/d running distance were chose as subjects. They were equally divided into four groups:

Proliferating cell nuclear antigen (PCNA) as a proliferative marker during embryonic and adult zebrafish hematopoiesis

We investigated the expression of proliferative cell nuclear antigen (PCNA) in zebrafish to delineate the proliferative hematopoietic component during adult and embryonic hematopoiesis. Immunostaining for PCNA and enhanced green fluorescence protein (eGFP) was performed in wild-type and fli1-eGFP (endothelial marker) and gata1-eGFP (erythroid cell marker) transgenic fish. Expression of PCNA mRNA was examined in wild-type and chordin morphant embryos. In adult zebrafish kidney, the renal tubules are surrounded by endothelial cells and it is separated into hematopoietic and excretory compartments. PCNA was expressed in hematopoietic progenitor cells but not in mature neutrophils, eosinophils or erythroid cells. Some PCNA+ cells are scattered in the hematopoietic compartment of the kidney while others are closely associated with renal tubular cells. PCNA was also expressed in spermatogonial stem cells and intestine crypts, consistent with its role in cell proliferation and DNA synthesis. In embryos, PCNA is expressed in the brain, spinal cord and intermediate cell mass (ICM) at 24 h-post fertilization. In chordin morphants, PCNA is significantly upregulated in the expanded ICM. Therefore, PCNA can be used to mark cell proliferation in zebrafish hematopoietic tissues and to identify a population of progenitor cells whose significance would have to be further investigated.     

Daily hyperhydration effect on electrolyte deficiency of endurance-Trained subjects during prolonged hypokinesia

The aim of this study was to evaluate the effect of a daily intake of fluid and salt supplementation (FSS) on the deficiency of electrolytes, which is characterized by higher rather than lower plasma concentration of electrolytes during prolonged hypokinesia (HK) (decreased number of km taken per day). Forty long distance runners aged 22–25 yr with a peak V0₂ 65.4 mL min^-1 kg^-1 with an average 14.2 km d running distance were selected as subjects. They were equally divided into four groups: 1) unsupplemented control subjects (UCS); 2) unsupplemented hypokinetic subjects (UHS); 3) supplemented hypokinetic subjects (SHS), and 4) supplemented control subjects (SCS). During the investigation of 364 d, groups 2 and 3 maintained an average running distance of less than 4.7 km per day, groups 1 and 4 did not experience any modification in their normal training routines and diets. During the preexperimental period of 60 d and during the experimental period of 364 d urinary excretion of electrolytes and concentrations of sodium, potassium, calcium, and magnesium in plasma were determined. Whole blood hemoglobin, hematocrit index, plasma osmolality, and plasma protein concentration were measured. In the UHS plasma concentration of electrolytes and urinary excretion thereof, fluid elimination, hematocrit, whole blood hemoglobin, plasma osmolality, and plasma protein concentration increased significantly (p < 0.05) when compared with the UCS, SCS, and SHS groups. In the SHS plasma concentration of electrolytes and urinary excretion thereof, fluid excretion, whole blood hemoglobin, hematocrit, plasma osmolality, and plasma protein concentration decreased when compared with the UHS and increased insignificantly when compared with the UCS and SCS groups. It was concluded that FSS may be used to prevent or minimize electrolyte deficiency in endurance-trained volunteers during prolonged restriction of muscular activity.     

红背山麻杆叶的化学成分研究(Ⅱ)——黄酮和苯乙醇苷类化合物

采用80％丙酮提取物的水萃取部位,利用凝胶、MCI、反相碳18、及 Toyopearl Butyl-650C 柱色谱进行分离纯化得到7个黄酮和3个苯乙醇苷类化合物。根据化合物的波谱数据分析鉴定为槲皮素(1)、槲皮苷(2)、异懈皮苷(3)、芦丁(4)、异牡荆素(5)、牡荆素(6)、木犀草素-7-O-α-L-鼠李糖(1→6)-β-D-葡萄糖苷(7)、2-phenethylβ-D-glucoside(8)、icariside D1(9)、2-苯乙基-D-芸香甙(10)。其中化合物1-3、5-6、8-10为首次从本属植物中分离得到。     

Src Regulates the Activity of the ING1 Tumor Suppressor

The INhibitor of Growth 1 (ING1) is stoichiometric member of histone deacetylase (HDAC) complexes and functions as an epigenetic regulator and a type II tumor suppressor. It impacts cell growth, aging, apoptosis, and DNA repair, by affecting chromatin conformation and gene expression. Down regulation and mislocalization of ING1 have been reported in diverse tumor types and Ser/Thr phosphorylation has been implicated in both of these processes. Here we demonstrate that both in vitro and in vivo, the tyrosine kinase Src is able to physically associate with, and phosphorylate ING1, which results in a nuclear to cytoplasmic relocalization of ING1 in cells and a decrease of ING1 stability. Functionally, Src antagonizes the ability of ING1 to induce apoptosis, most likely through relocalization of ING1 and down regulation of ING1 levels. These effects were due to both kinase-dependent and kinase-independent properties of Src, and were most apparent at elevated levels of Src expression. These findings suggest that Src may play a major role in regulating ING1 levels during tumorigenesis in those cancers in which high levels of Src expression or activity are present. These data represent the first report of tyrosine kinase-mediated regulation of ING1 levels and suggest that kinase activation can impact chromatin structure through the ING1 epigenetic regulator.