Crown of microfilaments in the extending cytoplasmic processes of medulloblastoma glial progenitors.

Microfilaments and microtubules play a part in the extension of neuronal processes but their roles in the formation of glial processes have not yet been determined. The objectives of this study were to determine the organization of microfilaments in differentiating glial progenitors (RB2 cells) and to study the effects of microfilament or microtubule disruption on process extension. Intense F-actin staining (crown of microfilaments) was observed at the leading edge of a small extending conical tip in differentiating RB2 cells, but was absent in process-bearing TE671 rhabdomyosarcoma cells. No significant difference was noted in the mean number of TE671 cells with processes treated with a microfilament disrupter from that of similarly treated controls. In contrast, a significant difference was noted in the mean number of RB2 cells with processes after microfilament disruption treatment from that of similarly treated controls. Microtubule disruption arrested extension and caused process retraction in both cell types. The results of this study demonstrate that microtubules play an equally important part in the extension and stabilization of the RB2 and TE671 processes. Moreover, the crown of microfilaments concentrated in the glial RB2 process (and not in the TE671 process) may be critical to its extension during differentiation.     

Prolactin,growth hormone and insulin-like growth factor-l in newborn children of smoking mothers*

OBJECTIVE Since maternal smoking causes fetal circulatory abnormalities, as well as disturbances of the maternal endocrine equilibrium, we measured the PRL, hGH and insulin-like growth factor-l (IGF-I) concentrations in the cord and venous blood of neonates of smoking mothers to determine whether or not the tobacco smoke affects the endocrine status of the neonate. DESIGN The above hormones were measured in the cord blood of the newborns of both smoking and non-smoking mothers. Also, PRL and hGH were determined at 24 and 72 hours after birth in newborns of both groups. PATIENTS Fifty-three newborns of smoking and 47 newborns of non-smoking mothers were investigated. Seventeen of the newborns of the smoking and 21 of the nonsmoking mothers were preterm. The remainder were full-term. MEASUREMENTS PRL was measured with a solid-phase immunoradiometric assay, hGH with a solid-phase two-site immunoradiometric assay and IGF-I with a solid-phase radioimmunoassay after extraction with acid-etha-nol. RESULTS The median value of PRL in the 17 preterm newborns of smoking mothers was 4941 mU/l (range 1322-7230), whereas in the 21 preterm newborns of nonsmoking mothers it was 2013 mU/l (range 243-4740) (P = 0 0002). The median hGH value in the above subjects was 1020 mU/l (range 35 2-208 4) and 59 8 mU/l (range 11 6-134-2), respectively (P = 0 0039). The median IGF-I was 580 7 U/l (range 253 2-4851 1) and 530 6 U/l (range 239 6-3591 5), respectively (P = 0 429). In the 36 full-term newborns of smoking mothers the median PRL value was 5171 mU/l (range 2074-7530), whereas in the 26 full-term newborns of non-smoking mothers it was 5081 (range 244-6540) (P = 0 048). The median hGH was 69 6 mU/l (range 42 3-280 0) and 32 2 mU/l (range 6 2-200 0), respectively (P = 0 0031). Also, the median IGF-I value was 926 3 U/l (range 348 5-5344 7) and 462 1 U/l (range 250 2-1578 7), respectively (P = 00024). On the 3rd day the PRL in the preterm neonates of both smoking and non-smoking mothers showed the same 16-5% drop, and thus the difference between the groups was maintained. A similar reduction in the hormone levels was observed in the full term neonates. CONCLUSIONS The findings indicate that the maternal tobacco-smoking causes disturbances of the endocrine status of the fetus, as shown by the increased levels of PRL, hGH and IGF-I, which are more pronounced between 30 and 37 weeks of gestation than at term.     

Effect of intervention to improve breastfeeding technique on the frequency of exclusive breastfeeding and lactation-related problems.

This randomized clinical trial compared frequencies of exclusive breastfeeding and lactation-related problems during the first 30 days among 74 mothers who received a 30-minute counseling session on breastfeeding technique in the maternity ward, and 137 controls. The frequency of exclusive breastfeeding among mothers who had received intervention was similar to controls by 7 days (79.7% vs 82.5%, respectively) and 30 days (60.8% vs 53.3%). There was no difference between groups in the frequency of sore nipples at 7 and 30 days, in breast engorgement and mastitis, and in the quality of breastfeeding technique at 30 days. Therefore, a single intervention at maternity was not sufficient to improve breastfeeding technique, increase exclusive breastfeeding rates, and reduce the incidence of breastfeeding problems during the first month.     

Cholesterol-sensing receptors, liver X receptor alpha and beta, have novel and distinct roles in osteoclast differentiation and activation.

The liver X receptor (alpha,beta) is responsible for regulating cholesterol homeostasis in cells. However, our studies using the LXRalpha-/-, LXRbeta-/-, and LXRalpha-/-beta-/- mice show that both LXRalpha and beta are also important for bone turnover, mainly by regulating osteoclast differentiation/activity. Introduction: The liver X receptors (alpha,beta) are primarily responsible for regulating cholesterol homeostasis within cells and the whole body. However, as recent studies show that the role for this receptor is expanding, we studied whether the LXRs could be implicated in bone homeostasis and development. MATERIALS AND METHODS: pQCT was performed on both male and female LXRalpha-/-, LXRbeta-/-, LXRalpha-/-beta-/-, and WT mice at 4 months and 1 year of age. Four-month-old female mice were additionally analyzed with reference to qPCR, immunohistochemistry, histomorphometry, transmission electron microscopy, and serum bone turnover markers. RESULTS: At the mRNA level, LXRbeta was more highly expressed than LXRalpha in both whole long bones and differentiating osteoblast-like MC3T3-E1 and osteoclast-like RAW 264.7 cells. Four-month-old female LXRalpha-/- mice had a significant increase in BMD because of an increase in all cortical parameters. No difference was seen regarding trabecular BMD. Quantitative histomorphometry showed that these mice had significantly more endosteal osteoclasts in the cortical bone; however, these cells appeared less active than normal cells as suggested by a significant reduction in serum levels of cross-linked carboxyterminal telopeptides of type I collagen (CTX) and a reduction in bone TRACP activity. Conversely, the female LXRbeta-/- mice exhibited no change in BMD, presumably because a significant decline in the number of the trabecular osteoclasts was compensated for by an increase in the expression of the osteoclast markers cathepsin K and TRACP. These mice also had a significant decrease in serum CTX, suggesting decreased bone resorption; however, in addition presented with an increase in the expression of osteoblast associated genes, bone formation markers, and serum leptin levels. CONCLUSIONS: Our findings show that both LXRs influence cellular function within the bone, with LXRalpha having an impact on osteoclast activity, primarily in cortical bone, whereas LXRbeta modulates trabecular bone turnover.     

Type 2 diabetes: assessment of endothelial lesion and fibrinolytic system markers.

This study aimed to investigate whether endothelial cells are damaged and to evaluate fibrinolytic system function in patients with type 2 diabetes. For this proposal, plasma levels of von Willebrand factor (an endothelial marker of injury), homocysteine (an inductor of endothelial injury), D-dimer (a marker of coagulation cascade activation) and plasminogen activator inhibitor-1 (a fibrinolysis marker) were measured in individuals with both type 2 diabetes and high blood pressure, with type 2 diabetes, with high blood pressure and in healthy control individuals. No significant differences among groups were observed for von Willebrand factor and homocysteine plasma levels. The type 2 diabetes and high blood pressure group presented a significant difference to the other groups for D-dimer and also presented high values for plasminogen activator inhibitor-1. The high blood pressure group and type 2 diabetes group presented separately higher values of plasminogen activator inhibitor-1 compared with the control group. High levels of D-dimer and plasminogen activator inhibitor-1 in patients with type 2 diabetes and high blood pressure with normoalbuminuria therefore indicate a state of hypercoagulability and hypofibrinolysis, despite no evident microvascular injury supported by normal levels of von Willebrand factor and homocysteine.     

Fast decomposition of water and lipid using a GRASE technique with the IDEAL algorithm.

Three-point Dixon techniques achieve good lipid-water separation by estimating the phase due to field inhomogeneities. Recently it was demonstrated that the combination of an iterative algorithm (iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL)) with a fast spin-echo (FSE) three-point Dixon method yielded robust lipid-water decomposition. As an alternative to FSE, the gradient- and spin-echo (GRASE) technique has been developed for efficient data collection. In this work we present a method for lipid-water separation by combining IDEAL with the GRASE technique. An approach to correct for errors in the lipid-water decomposition caused by phase distortions due to the switching of the readout gradient polarities inherent to GRASE is presented. The IDEAL-GRASE technique is demonstrated in phantoms and in vivo for various applications, including pelvic, musculoskeletal, and (breath-hold) cardiac imaging.