Effects of growth and annealing temperatures on the structural and the optical properties of In0.6Al0.4As/Al0.4Ga0.6As quantum dots

In0.Al0.4As/Al0.4Ga0.6As quantum dots (QDs) were grown on GaAs (001) substrates by using molecular beam epitaxy utilizing a modified Stranski-Krastanow method. Atomic force microscopy images showed that the size of the In0.6Al0.4As QDs increased with increasing growth temperature. Photoluminescence spectra at 300 K showed that the exciton peaks corresponding to the interband transitions from the ground electronic subband to the ground heavy-hole subband (E1-HH1) of the In0.6Al0.4As/Al0.4Ga0.6As QDs shifted to large energy side with increasing growth temperature resulting from an increase in the height of the In0.6Al0.4As QDs. While the (E1-HH1) peak position of the PL spectra shifted toward larger energy side with increasing up to an annealing temperature of 700 °C, it shifted toward lower energy above 700 °C. The structural and the optical properties of In0.6Al0.4As/Al0.4Ga0.6As QDs were affected by the growth and annealing temperatures.

Effects of growth parameters on the structural and optical properties of InP/InGaP quantum structures for 808-nm-wavelength emissions

InP/InGaP quantum structures with 808-nm-wavelength emissions were grown on semi-insulating GaAs (100) substrates via migration-enhanced molecular beam epitaxy. The effects of the growth conditions on the structural and optical properties of the InP/InGaP quantum structures were investigated. The scanning electron microscopy and atomic force microscopy images showed that the two-dimensional InP/InGaP quantum structures were transited to one-dimensional structures with an increasing repetition cycle. The photoluminescence spectra showed that the optical properties of the InP/InGaP quantum structures were significantly affected by various migration-enhanced epitaxy repetition numbers and growth temperatures. These results can help improve understanding of the effects of growth parameters on the structural and optical properties of InP/InGaP quantum structures for 808-nm-wavelength emissions.

Self-assembled growth of GaAs anti quantum dots in InAs matrix by migration enhanced molecular beam epitaxy

Self-assembled GaAs anti quantum dots (AQDs) were grown in an InAs matrix via migration enhanced molecular beam epitaxy. The transmission electron microscopy image showed that the 2D to 3D transition thickness is below 1.5 monolayers (MLs) of GaAs coverage. The average diameter and height of the GaAs AQDs for 1.5 ML GaAs coverage taken from the atomic force microscopy image were approximately 29.0 nm and 1.4 nm, respectively. The density was approximately 6.0 x 10(10) cm(-2). The size of the AQDs was enlarged in the InAs matrix compared with that on the surface. These results indicate that the GaAs AQDs in the InAs matrix under tensile strain can be effectively formed with the assistance of the migration enhanced epitaxy method.

Nonassociation of interleukin-1 receptor antagonist genotypes with bone mineral density, bone turnover status, and estrogen responsiveness in Korean postmenopausal women

Interleukin-1 receptor antagonist (IL-1ra), a natural inhibitor of interleukin-1 (IL-1), completely inhibits the stimulatory effects of IL-1 on bone resorption. Bioactivity of IL-1 increases in the estrogen-deficient state with an increased IL-1:IL-1ra ratio and decreases after estrogen replacement therapy with a decreased IL-1:IL-1ra ratio. An association was found between an 86 basepair variable number tandem-repeat (VNTR) polymorphism of the IL-1ra gene and an increased production of IL-1ra in a cultured monocyte system. The IL-1ra VNTR polymorphism, therefore, is an attractive candidate gene for osteoporosis susceptibility as well as hormone responsiveness after estrogen replacement. We examined the association of this VNTR polymorphism with bone mass, bone turnover, and the change of bone mineral density (BMD) after 1 year of hormone replacement therapy (HRT). The frequencies of the five alleles were as follows: A1, 90.8% (410 bp, four repeats); A2, 7.2% (240 bp, two repeats); A3, 1.6% (500 bp, five repeats); A4, 0.4% (326 bp, three repeats); and A5, 0% (595 bp, six repeats), in 714 healthy ethnically Korean postmenopausal women, aged 41-74 years (55.2 +/- 6.3 years mean +/- SD). Spine (L2-4) and femoral neck BMD were not significantly different among IL-1ra genotypes, and no significant genotypic differences were found in bone markers. There were no differences in genotypic proportions when we categorized the subjects into a high-loss group and a normal-loss group with regard to levels of bone marker. No significant genotypic differences were found in changes in lumbar and femoral neck BMD and those in bone markers before and after 1 year of HRT in 312 women. Our data suggest that these IL-1ra polymorphisms are not associated with BMD, bone turnover, or the change of BMD after 1 year of HRT in Korean women.

Deflazacort increases osteoclast formation in mouse bone marrow culture and the ratio of RANKL/OPG mRNA expression in marrow stromal cells

Information on precise effects of deflazacort on bone cell function, especially osteoclasts, is quite limited. Therefore, the present study was undertaken to test effects of deflazacort on osteoclast-like cell formation in mouse bone marrow cultures and on the regulation of osteoprotegerin (OPG) and its ligand (RANKL) mRNA expressions by RT-PCR in the ST2 marrow stromal cells. TRAP-positive mononuclear cells increased after the treatment of deflazacort at 10(-9) to 10(-7) M alone for 6 days in a dose-dependent manner. Number of TRAP-positive multi-nucleated cells (MNCs) increased significantly with combined treatment of deflazacort at 10(-7) M and 1,25-(OH)2D3 at 10(-9) M compared to that of cultures treated with 1,25-(OH)2D3 alone (p<0.05). Exposure to deflazacort at 10(-7) M in the presence of 1,25-(OH)2D3 at 10(-9) M in the last 3-day culture had greater stimulatory effect on osteoclast-like cell formation than that of the first 3-day culture did. Deflazacort at 10(-10) -10(-6) M downregulated OPG and upregulated RANKL in mRNA levels in a dose-dependent manner. These observations suggest that deflazacort stimulate osteoclast precursor in the absence of 1,25-(OH)2D3 and enhance differentiation of osteoclasts in the presence of 1,25-(OH)2D3. These effects are, in part, thought to be mediated by the regulation of the expression of OPG and RANKL mRNA in marrow stromal cells.

Identification of a mutation in the human raloxifene response element of the transforming growth factor-beta 3 gene

The human transforming growth factor-beta 3 (TGF-beta 3) is an important cytokine to maintain bone mass by inhibiting osteoclast differentiation. Recently raloxifene response element (RRE), a new enhancer with a polypurine sequence for estrogen receptor (ER)-mediated gene activation, was identified on the TGF-beta 3 gene. Functional analysis of the RRE-mediated pathway has shown that this would be an important pathway for bone preserving effect. We found a novel mutation in the RRE sequence by single-strand conformational polymorphism analysis in one of 200 Korean women. Cloning and sequencing revealed a heterozygote in which one allele had an insertion of 20 nucleotides (AGAGAGGGAGAGGGAGA GGG) between nucleotide +71 and +72 and a point mutation at nucleotide +75 (G-A transition), and the other allele had normal sequence. The insertion was a nearly perfect tandem duplication of the wild type DNA sequence. The bone mineral density of the affected woman was not much lower than that of age-matched controls. Transient transfection of the mutant allele showed no significantly different activity compared with that of the wild type allele. These observations suggest that the heterozygote variation of the RRE sequence seems not to be operative in determination of bone mass.

Metabolic characteristics and prevalence of osteoporosis among women in Tae-An area

Understanding the metabolic changes in women is one of the important ways to prevent and treat osteoporosis. To reveal the metabolic characteristics of 289 healthy women aged between 35-65 yr in Tae-An, Korea we evaluated the association between bone mass assessed by broadband ultrasound attenuation (BUA) using quantitative ultrasound 2 (QUS2) and various parameters such as age, body mass index, serum levels of alkaline phosphatase, calcium, phosphorus, parathyroid hormone, 25(OH)D, and urinary ratios of calcium/creatinine and deoxypyridinoline (Dpyd)/creatinine. Among the subjects, 3.0% were osteoporotic, and 40.9% were osteopenic. When the subjects were classified according to their years since menopause (YSM) and age, the prevalence of osteoporosis increased along with an increase of YSM and age. Bone turnover markers such as serum alkaline phosphatase and fasting urinary Dpyd/creatinine were significantly higher in the group with low bone mass than in the normal group. In summary, this study shows, by use of biochemical markers of bone turnover and QUS2, the prevalence of osteoporosis in women aged between 35-65 in Tae-An was 3.0% and the risk of low bone mass increased with the bone turnover markers.

A nonlinear model for mammary gland growth and regression in lactating sows

The objective was to propose an empirical mathematical model to describe mammary gland growth and regression in lactating sows. A nonlinear dynamic model based on the logistic function was constructed, and data from 61 sows were used to illustrate the model. Sows were fed four diets with two levels of energy and of protein during lactation, and individuals were slaughtered over a 30-d period to produce a cross sectional data set on weight and composition variables from suckled mammary glands. Data (y(x)) were obtained for each day of lactation (x) and fitted by nonlinear regression. The logistic distribution function was modified for different durations of growth (f; days/gram of weight or composition) and regression (g; days/gram of weight or composition): [formula in text] where y(max) is maximum weight or composition and x(max) is day of lactation at maximum. Based on results for wet weight, for example, individually suckled mammary glands grow until between Day 21 and 28 of lactation and reach a maximum of about 500 to 600 g, depending on diet. Growth pattern of mammary glands can be described well with an asymmetric nonlinear model, using different durations for growth and regression. From this model, it was possible to estimate directly biologically important parameters: maximum weight or composition, day of lactation at maximum weight or composition, and durations of growth and regression. This model can be applied to describe mammary gland growth patterns for other species and to describe similar growth or production patterns.

How reliable is the ultrasound densitometer for community screening to diagnose osteoporosis in spine, femur, and forearm?

Dual X-ray absorptiometry (DXA) is the most widely used noninvasive, quantitative diagnostic method of measuring bone density, but it exhibits several limitations for the purpose of general screening and community-based study. Thus, we evaluated the feasibility of the ultrasound densitometer SoundScan Compact for screening the osteoporosis community. We compared the reliability of the SoundScan Compact's measurement to predict both osteopenia and osteoporosis at the spine, femur, and forearm measured by the XR-36. World Health Organisation criteria and Korean reference were used for the diagnosis of osteopenia and osteoporosis. Of the 1827 subjects screened in the community, we randomly selected and invited 106 subjects to our university hospital center for clinical epidemiology for further evaluation of their bone health using DXA. The site-specific relationships among speed of sound and bone mineral density at L2-L4 spine, femoral neck, trochanter, Ward's triangle, distal radius + ulna, proximal radius + ulna, and proximal radius were highly correlated with r values of 0.633, 0.632, 0.674, 0.632, 0.668, 0.78, and 0.777 respectively (all p < 0.0001). Of the 42 subjects defined as normal in the spine by SoundScan Compact's, 27 (64.3%) were also in agreement as the normal by the XR-36. However, an agreement of 43.5% (10/23) in osteopenia and 53.7% (22/41) in osteoporosis was less sensitive. Reliability tested by kappa statistics (kappa = 0.35; t = 5.3; p < 0.0001) revealed that the degree of agreement was not coincidental. On the femur, 54.8% (23/42) agreed as normal, 73.9% (17/23) as osteopenia, and 39% (16/41) as osteoporosis (kappa = 0.33; t = 5.5; p < 0.0001). Higher reliability was found in the forearm, with a kappa value of 0.48, t = 7.2, and p < 0.0001. A magnitude of agreement was also greater in the forearm, with 83.3% (35/42) agreement in normal, 52.2% (12/23) in osteopenia, and 64% (16/25) in osteoporosis. Although the SoundScan Compact's measures different bone properties and measurements are taken at different sites, it is a very useful instrument with a high correlation and high degree of variation and reliability to predict bone health at other sites such as the spine, femur, and forearm. The ultrasound densitometer such as SoundScan Compact's merits its use for community screening and in the primary care setting to detect osteopenia and osteoporosis for the purpose of early detection and prevention.

Kinetics of carnitine palmitoyltransferase-I are altered by dietary variables and suggest a metabolic need for supplemental carnitine in young pigs

To examine the kinetics of carnitine palmitoyltransferase-I (CPT-I) and the influence of dietary variables, young pigs (18 kg, n = 20) were fed corn-soybean meal diets supplemented with 40 g soy oil/kg and containing either 136 or 180 g crude protein/kg and either 0 or 500 mg/kg L-carnitine (2 x 2 factorial design). Diets were offered for 10 d (85% of ad libitum); CPT-I activities in liver and skeletal muscle mitochondria were determined, and enzyme kinetic constants (V:(max) and K:(m) for carnitine) were estimated. Kinetics of CPT-I in muscle were not affected by diet (P: > 0.1; carnitine K:(m) = 480 +/- 44 micromol/L). In contrast, the K:(m) for carnitine in liver was increased from 164 to 216 +/- 20 micromol/L by dietary L-carnitine supplementation (P: < 0.01) and from 169 to 211 +/- 20 micromol/L by high protein feeding (P: < 0.05). Dietary L-carnitine increased muscle and liver free carnitine concentrations by 72 and 158% over control concentrations (770 and 80 micro;mol/kg wet muscle and liver, respectively). Because tissue carnitine concentrations were within the range of the respective K:(m) for both liver and muscle tissue, it is inferred that alteration of tissue carnitine concentrations via dietary supplementation could modulate CPT-I activity in young pigs.

Method and complications of ileocutaneous anastomosis for collection of ileal digesta in neonatal pigs

The purpose of our study was to develop a surgical method for collection of ileal digesta in neonatal (< 5 kg) pigs and to determine potential complications of the procedure. In 18 10-day-old pigs, we performed ileocutaneous anastomosis (ICA) via a right ventrolateral incision. The ICA was readily performed in these neonatal pigs; one pig died 24 hours after surgery because of intestinal volvulus. Pigs were monitored twice daily for development of post-operative complications. Ileal digesta were collected "free-catch" by using metabolism cages because attempts to use cannulas (diameter, 4 to 8 mm) and collection bags failed. To determine the effect of colon bypass on hydration, electrolytes, glucose, and serum enzyme activities, we collected serum biochemistry data before and 6 days after surgery. Changes in serum biochemical values included increased potassium, creatinine, total protein, albumin, and globulin and decreased ALP and glucose, but all values remained within normal ranges for neonatal pigs. ICA is tolerated well by neonatal pigs and is an easily learned and rapid technique for collection of ileal digesta. In addition, ICA is a useful alternative to "T-cannulas" and ileorectal anastomosis for nutrition research using neonatal pigs weighing < 5 kg.

Dietary L-carnitine improves nitrogen utilization in growing pigs fed low energy, fat-containing diets

Growing pigs (n = 25; 17.8 +/- 0.1 kg) were used to study the effects of L-carnitine and protein intake on nitrogen (N) balance and body composition. Fat-supplemented (40 g soy oil/kg diet), corn-soybean meal basal diets containing low or high protein (136 or 180 g/diet) were formulated so that protein accretion would be limited by metabolizable energy (ME). Each basal diet was supplemented with 0 or 500 mg/kg L-carnitine and fed to pigs for 10 d in a nutrient balance trial. Final body composition was compared with weight and age-matched pigs measured on d 0 to calculate nutrient accretion rates. High protein feeding increased (P < 0.01) average daily gain (ADG) by 34%, as well as nitrogen digestibility (4.4%), retention (5.2%), urinary excretion (29%) and crude protein (CP) accretion (33%). Total-body carnitine accretion rate was 4.5 fold greater and total body carnitine concentration was almost 100% greater than in unsupplemented controls (P < 0.01). Irrespective of protein level, carnitine increased ADG (by 7.3%, P < 0.10) and CP accretion rate (9%, P < 0.10). Congruently, carnitine supplementation improved the efficiency of nitrogen retention (P < 0. 05) and reduced urinary nitrogen excretion (14%, P < 0.10). Carcass fat content also was reduced in carnitine-supplemented pigs (P < 0. 10). Collectively, these data support the hypothesis that carnitine can improve the efficiency of nitrogen utilization in 20-kg pigs fed energy-limited, fat-containing diets. We conclude that endogenous carnitine biosynthesis may be adequate to maintain sufficient tissue levels during growth, but that supplemental dietary carnitine (at 500 mg/kg) may be retained sufficiently so as to alter nutrient partitioning and thus body composition of 20-kg pigs.

Effect of nutrient intake on mammary gland growth in lactating sows

Sixty-one primiparous sows were used to determine the response of mammary gland growth to different energy and protein intakes during lactation. After birth, litter size was set to 9 or 10 pigs. Sows were slaughtered at selected times up to 30 d of lactation. Individual sows were fed one of four diets that were combinations of different amounts of energy and protein (3.0 Mcal ME and 8.0 g lysine/kg diet; 3.0 Mcal ME and 16.2 g lysine/kg diet; 3.5 Mcal ME and 6.4 g lysine/kg diet; or 3.5 Mcal ME and 13.0 g lysine/kg diet). Mammary glands were collected at slaughter and trimmed of skin and the extraneous fat pad. Each gland was weighed, cut in half to measure cross-sectional area, ground, and stored at -20 degrees C for chemical analysis. Frozen, ground tissue was used to determine dry matter, dry fat-free tissue (DFFT), total tissue protein, ash, and DNA content. Only glands known to have been suckled were included in this data set. Response surface regression was used for statistical analysis. The percentage of protein, fat, ash, and DNA in each suckled mammary gland was affected only by total energy intake (P<.05). The percentage of dry tissue and fat decreased as the total energy consumed during lactation increased, whereas the percentage of protein and DFFT increased as total energy intake increased. There were quadratic effects (P<.05) of both total energy and protein intake on wet weight, dry weight, protein amount, DFFT amount, and DNA amount of each suckled mammary gland during lactation. This study shows that mammary gland growth is affected by nutrient intake during lactation. The weight of suckled mammary glands and the amount of mammary tissue protein, DFFT, and total DNA were maximal on d 27.5 of lactation when sows had consumed an average of 16.9 Mcal of ME and 55 g of lysine per day during lactation. Provision of adequate amounts of nutrients to sows during lactation is important for achieving maximal growth of mammary glands and maximal milk production.

Changes in tissue composition associated with mammary gland growth during lactation in sows

Twenty-four primiparous sows were used to determine the extent of mammary gland growth during lactation. Litter size was set to nine or 10 pigs immediately after birth. Sows were slaughtered in groups representing d 0 (within 12 h after farrowing), 5, 10, 14, 21, and 28 of lactation. Sows were provided 17.5 Mcal ME and 65 g of lysine per day during lactation. Mammary glands were collected at slaughter and trimmed of skin and extraneous fat pad. Each gland was weighed, cut in half to measure cross-sectional area, and ground for chemical analysis. Dry matter content, dry fat-free tissue (DFFT) content, protein content, amino acids composition, ash content, and DNA content were measured. Only glands known to have been suckled were included in these data. Wet and dry tissue weight; cross-sectional area; and the amount of DFFT, tissue protein, and amino acids in each suckled mammary gland increased (P < .05) during lactation to a peak on d 21. Fat percentage of each suckled gland declined (P < .05) and the percentage of protein and DFFT increased (P < .05) as lactation progressed. These results suggest that hypertrophy occurred in the tissue during lactation. There was a linear increase in the amount and percentage of DNA during lactation (P < .05), suggesting hyperplasia of the mammary tissue. Mammary tissue growth continues in suckled glands during lactation in sows, with gland wet weight increased by 55% and total gland DNA increased by 100% between d 5 and 21 of lactation.

Lack of an intronic Sp1 binding-site polymorphism at the collagen type I alpha1 gene in healthy Korean women

Osteoporosis is a disease that is strongly genetically influenced. However, the genes responsible for the disease are poorly defined. Recent data show that a G-T transition polymorphism of the Sp1 binding site at the collagen type I alpha1 gene (Sp1 polymorphism) is associated significantly with bone mineral density (BMD) and osteoporotic fracture in British women. To establish the association between the Sp1 genotypes and BMD in Korean women, we examined 200 healthy postmenopausal women of Korean ethnicity, ranging in age from 44 to 66 years (mean+/-SD: 54.7+/-5.3 years). PCR amplification using the same primers as those used previously, with enzyme digestion, revealed no restriction site in our samples. We also performed a single-strand conformational polymorphism (SSCP) analysis in 100 of the 200 samples and could not find any polymorphic sites in the PCR amplification region. Based on our study, the Sp1 polymorphism at the type I collagen alpha1 gene was not found in Korean women. Therefore, we suggest that the Sp1 polymorphism at the type I collagen alpha1 gene is absent or rare in Korean women. Based on the present findings, this polymorphism does not seem to be responsible for the entire genetic contribution to BMD.

Increased macrosomia and perinatal morbidity independent of maternal obesity and advanced age in Korean women with GDM

OBJECTIVE

To examine the impact of gestational diabetes mellitus(GDM) on perinatal outcome in a setting where influences of maternal age and obesity would be minimal.

RESEARCH DESIGN AND METHODS

A case-control study was done to compare the outcome of pregnancy in 65 women with GDM and 153 women with normal carbohydrate metabolism matched for age, height, and prepregnancy weight.

RESULTS

The frequencies of preeclampsia and primary cesarean sections were higher and delivery was earlier in pregnancies complicated by GDM. Birth weight, symmetry index, and chest circumference were greater, and macrosomia and need for phototherapy were more common in offspring of mothers with GDM. Cord-serum C-peptide and insulin concentrations were higher in the infants of mothers with GDM and were strongly correlated with birth weight and symmetry index. However, maternal age, prepregnancy weight, and prepregnancy BMI were not correlated with birth weight. Postprandial glucose levels during the first 2 weeks after diagnosis of GDM had associations with the infants' birth weight, symmetry index, and cord insulin concentration in the diet-treated patients with GDM.

CONCLUSIONS

Antepartum maternal glucose metabolism was significantly associated with fetal hyperinsulinemia and excessive fetal growth in relatively nonobese Korean women. These findings support a direct role for metabolic factors in the adverse outcomes in pregnancies complicated by GDM.

Nonassociation of estrogen receptor genotypes with bone mineral density and estrogen responsiveness to hormone replacement therapy in Korean postmenopausal women

Hormone replacement therapy (HRT) prevents bone loss in postmenopausal women, but some women are resistant to therapy. A recently reported case of severe estrogen resistance caused by a germline mutation at the estrogen receptor (ER) gene locus suggests the possibility that other variants of the ER gene could be responsible for resistance to HRT and could also be an answer to the heritable components of bone density. Three restriction fragment length polymorphisms (RFLPs) at the ER gene locus, represented as BstUI (or B variant), PvuII, and XbaI, and their relationship to bone mineral density (BMD) and estrogen responsiveness to HRT were examined in 248 healthy postmenopausal women, aged 41-68 yr (mean +/- SD, 52.0 +/- 4.6 yr) in Korea. The BstUI restriction site was not found in Korean women. The distribution of the PvuII and XbaI RFLPs was as follows: PP, 35 (14.1%); Pp, 136 (54.8%); pp, 77 (31.1%) and XX, 18 (7.3%); Xx, 72 (29.0%); and xx, 158 (63.7%), respectively (capital letters signify the absence of and lower case letters signify the presence of the restriction site of each RFLP). There was no significant relation between ER genotypes and z score values of lumbar spine BMD. Also, no significant genotypic differences were found in the change in lumbar spine BMD and those in biochemical markers before and after 1 yr of HRT. These data indicate no significant effects of ER genotypes on BMD and estrogen responsiveness after HRT.

Compensatory growth in dairy heifers: the effect of a compensatory growth pattern on growth rate and lactation performance

The objective of this study was to improve the efficiency of growth and lactation performance of dairy heifers fed for a stair-step growth pattern. Twenty-four young Holstein heifers were randomly assigned to either control or test groups. The test group was fed according to a schedule of 3, 2, 4, 2, 5 and 2 mo in which feed intake was alternately 20% below or 25% above requirements. Heifers that were subjected to the stair-step growth pattern gained more body weight and consumed less dry matter, resulting in improved efficiency of growth compared with that of controls (7.8% vs. 8.3%). First estrus, first conception, gestation period, services per conception, and calving difficulty (dystocia) were not affected by stair-step growth. Concentration of growth hormone in blood serum was elevated during feed restriction for the test heifers; however, during refeeding, growth hormone was decreased compared with that in the blood serum of control heifers. Mammary tissues obtained by biopsy from heifers in middle and late pregnancy were used for chemical composition analysis. Stair-step growth increased DNA, RNA, protein, the ratio of RNA to DNA, and the ratio of protein to DNA. Lipid decreased in the mammary tissue of test heifers in late pregnancy (9.5 mo). Heifers in the test group yielded approximately 9% more milk than did heifers in the control group. These results indicate that compensatory growth can contribute to the improvement of growth efficiency and lactation performance.

Lack of a direct effect of estrogen on proliferation and differentiation of normal human osteoblast-like cells

Although osteoblasts contain estrogen receptors, it is unclear whether estrogen has direct effects on osteoblast proliferation and differentiation. We evaluated the effects of 17 beta-estradiol treatment (1 pM to 10 nM) on the proliferation and differentiation of cultured normal adult human cells that expressed many of the phenotypic characteristics and hormonal sensitivities of mature osteoblasts (hOB cells). Treatment of hOB cells with estradiol for as long as 144 h did not affect the rate of DNA synthesis and had minimal, if any, effects on differentiated function. Whereas alkaline phosphatase activity was increased by nearly twofold (P less than 0.01) when the hOB cells were treated with 1 nM 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3], treatment with estradiol had no effect when given alone and did not affect the cells' response to 1,25-(OH)2D3. Similarly, the release of bone gla protein (BGP, osteocalcin) was induced by treatment with 1,25-(OH)2D3 (P less than 0.05), but estradiol treatment did not affect this response. Cellular levels of mRNA for alkaline phosphatase and BGP were not altered by estradiol treatment. We conclude that estradiol treatment does not have major effects on the growth or differentiation of cultured hOB cells. These results are consistent with previous observations in vivo that indicate estrogen acts principally to decrease bone resorption, not to modulate its formation.

The changes of serum-ACE, plasma renin activity and aldosterone in the diabetics with hypertension

It is well known that the serum-ACE levels are elevated in sarcoidosis, Gaucher’s disease, and some granulomatous diseases. Recently, the serum-ACE level was also found to be elevated in diabetes mellitus. To confirm the possible role of plasma renin activity and aldosterone in the pathogenesis of hypertension and to assess the relationship of serum ACE to the plasma renin activity and aldosterone profiles in diabetics, we measured the levels of serum ACE, plasma renin activity, aldosterone and blood pressure in 38 diabetic patients who were admitted to Kyung Hee University Hospital from June 1981 to September, 1982. The results were as follows: 1. The S-ACE activity was significantly elevated in 38 patients with diabetes mellitus (9.42±6.60 Unit) as compared with that in the healthy controls (2.53±1.54 Unit) (p<0.005) (p<0.005). 2. The S-ACE activity was significantly elevated in 15 hypertensive diabetics (14.29± 7.10 Unit) as compared with that in 23 normotensive diabetics (6.24±3.68 Unit) (p<0.005). 3. The S-ACE activity was elevated in 15 diabetic patients with retinopathy (10.6±4.7 Unit) as compared with the levels in 17 diabetic patients without retinopathy (6.7±4.8 U) (p<0.05). 4. The S-ACE activity was directly correlated to the mean arterial pressure (r=0.54) (p<0.005). 5. The plasma renin activity and aldosternone concentrations in diabetics were not different from the normal controls and had no correlationship to the S-ACE activity. 6. After 2 weeks of insulin therapy in 15 diabetics, the S-ACE activity was not changed.

Dietary interaction of phosphorus with sodium from either chloride or bicarbonate affects laying hen performance

Experimental diets consisting of two levels of total phosphorus (.30 and .75%) and three different treatments of supplemental sodium (.35% NaCl, 1.40% NaCl, and .35% NaCl plus 1.50% NaHCO3) were fed in a 2 X 3 factorial arrangement to laying hens for 16 weeks. The latter two treatments of sodium were designed to supply the same level of sodium (.55%) from different chemical forms. Hens fed .30% phosphorus laid significantly (P less than .01) less eggs than those fed .75% phosphorus. A highly significant (P less than .01) interaction was found between phosphorus and sodium treatments. The high level of sodium from either chloride or bicarbonate decreased egg production at the lower level of phosphorus and increased it when the higher level of phosphorus was fed. Sodium bicarbonate affected egg production more strongly than sodium chloride did. There were no significant treatment effects on egg weight and egg shell weight. Addition of sodium bicarbonate to the low phosphorus diet significantly (P less than .05) decreased feed consumption of the hen. Supplemental sodium bicarbonate with either level of dietary phosphorus significantly (P less than .05) increased percent nitrogen retention of the hen, but excessive sodium chloride did not.