High pressure behavior of ethylene and water: From clathrate hydrate to polymerization in solid ice mixtures.

Among the ice mixtures that can be found in our universe, those involving ethylene are poorly studied even though ethylene reportedly exists in the presence of water in several astrochemical domains. Here, we report on the chemistry of ethylene and water mixtures in both pressure (0-15 GPa) and temperature (300-370 K) ranges relevant to celestial bodies conditions. The behavior of the binary mixture has been tracked, starting from the ethylene clathrate hydrate and following its evolution through two different crystalline phases up to 2.10 GPa, where it decomposes into a solid mixture of water ice and crystalline ethylene. The pressure and temperature evolution of this mixture has been studied up to the complete transformation of ethylene into polyethylene and compared with that of the pure hydrocarbon, reporting here for the first time its spectroscopic features upon compression. The spectroscopic analysis of the recovered polymers from the ice mixtures provided hints about the reactivity of the monomer under the environmental stress exerted by the water network. The results of this study are expected to be significant in a variety of fields ranging from astrochemistry to material science and also to fundamental chemistry, particularly regarding the study and modelization of the behavior of complex mixtures.

Causes of accidents in pediatric patients: what has changed through ages.

AIM: Accidents are the main cause of death and disability in children and adolescents aged 1-15 years and cause more than one sixth of all infant admissions to hospital. In Italy, about 400 children and adolescents are involved in domestic accidents and more than 200 in road accidents. The aim of the study was to determine the number and type of accidents involving children and adolescents in the area of Siena and to compare present results with those obtained 20 years ago in order to assess the effectiveness of preventive measures evolving in the period. METHODS: Two groups of patients were admitted to the hospital of Siena for accidents between 1980-1985 and 2000-2006; age, gender, type of accident, frequency distribution in the study period and age of highest frequency of accidents were analysed. RESULTS: The most frequent cause of admission to hospital in the earlier period was limb trauma with and without fracture, whereas in the later period it was head injury without fracture followed by limb trauma with and without fracture, and fracture of the skull, spine and trunk in boys and girls. Some variation in the course of the years was observed in both study period, however a constant, gradual reduction in admissions is evident. CONCLUSION: Comparison of these data with those collected 20 years earlier revealed a general reduction in the number of hospital admissions. This encouraging result suggests that what has been done so far is effective and should be continued, and that it is also worthwhile taking measures to further reduce the toll of accidents.

Effects of intermittent parathyroid hormone (PTH) administration on SOST mRNA and protein in rat bone.

Sclerostin, the secreted protein product of the SOST gene, which is mainly expressed by osteocytes, has recently been proposed as a negative regulator of bone osteoblastogenesis. Chronic elevation of PTH reduces SOST expression by osteocytes, while controversial results have been obtained by intermittent PTH administration. We have investigated the effects of intermittently administered PTH on SOST expression and sclerostin localization, comparing them with those of controls, as they appeared in three different bone segments of rat tibia: secondary trabecular metaphyseal and epiphyseal bone, and cortical diaphyseal bone. The histomorphometric results demonstrate that PTH enhances bone turnover through anabolic effects, as shown by the association of increased bone resorption variables with a significant rise in BV/TV, Tb.Th and Tb.N and a fall in Tb.Sp. PTH induces a SOST mRNA and protein fall in secondary metaphyseal trabeculae, diaphyseal bone and in epiphyseal trabeculae. Numbers of sclerostin immunopositive osteocytes/mm(2) show no change, compared with controls; there are fewer sclerostin-positive osteocytes in secondary metaphyseal trabeculae than in the other two bone areas, both in the control and PTH groups. The low numbers of sclerostin-positive osteocytes in the metaphyseal trabecular bone seem to be directly related to the fact that this area displays a high remodeling rate. The anabolic effects of PTH are in line with the fall of SOST mRNA and protein in all the three bone segments examined; the rise of bone turnover supports a negative role of SOST in bone formation.

Blood pressure in the small-for-gestational age newborn.

AIM: The aim of the paper is to verify the existence of an inverse correlation between birth weight and blood pressure (BP) in neonates, infants and adolescents. METHODS: BP was measured at 7 days, 3, 6, 9, 12 months and 7-18 years in 432 subjects born at term at the Department of Pediatrics, Obstetrics and Reproductive Medicine, University of Siena; 228 of these subjects were small for gestational age (SGA) and 204 appropriate for gestational age (AGA). For small babies, BP was measured with a DYNAMAP oscillometer which provides digital visualisation of systolic, diastolic and mean arterial pressure and heart rate. In older children, a mercury sphygmomanometer was used. Statistical analysis was carried out with SPSS 8.01 software using the Kolmogorov-Smirnov test for normality of populations. RESULTS: Statistical analysis did not reveal any significant differences between SGA and AGA subjects in the various age classes of the first 12 months of life. Significant correlation was found between 7 and 18 years with differences in the various age classes for systolic pressure. Subjects with normal birthweight had lower systolic and diastolic BP. SGA males had higher risk of high systolic and diastolic pressure, whereas SGA females were only at higher risk for elevated diastolic pressure. CONCLUSIONS: SGA subjects should be monitored for BP and life-style between 7 and 18 years to risk of cardiovascular disease.

Localization of the glucocorticoid receptor mRNA in cartilage and bone cells of the rat. An in situ hybridization study.

The in vivo localization of glucocorticoid receptor (GR) mRNA expression was studied in the cartilage and bone cells of the femur of young adult rats to compare its distribution with that of the GR protein, which had previously been shown histochemically in the same areas. To achieve this, we used a synthetic oligodeoxynucleotide as a probe, in line with the published human GR (hGR) cDNA sequence. The probe was coupled to fluorescein (FL), applying a rapid Fast-Tag TM FL nucleic acid labeling method. Negative controls were achieved by using sense sequences of the hGR oligoprobe, similarly coupled by using the Fast-Tag TM FL labeling kit. Dewaxed sections were treated for in situ hybridization (ISH) histochemistry with the antisense and sense oligoprobes. The ISH reaction product was more intense in the cytoplasm of proliferative and maturative chondrocytes of the growth plate cartilage than in that shown in the hypertrophic ones. In the metaphyseal secondary ossification zone, osteoblasts (OBs) and osteocytes (OCs) were variably labeled, whereas osteoclasts (OCLs) were always intensely stained. The labeling was also visible in some bone marrow cells, in articular chondrocytes, in the cells of tendon-bone junctions, and in the perichondrium and periosteal cells. Our results confirm a cellular co-location of GR protein and mRNA. In agreement with GR immunolocalization, the variability of labeling appeared to be related to the cell cycle, the stage of differentiation and cell-type differences.

Antioxidant erythrocyte enzyme activities during oral contraception.

Nineteen healthy young women, non-smokers and of normal weight, used a combined oral contraceptive, consisting of 20 micrograms ethinylestradiol and 150 micrograms desogestrel, for 9 cycles and were investigated before starting oral contraceptive use, and during the 3rd, 6th and 9th cycle. In all cases, the antioxidant erythrocyte enzyme activities, superoxide-dismutase (SOD), catalase (CAT) and glutathione-peroxidase (GSH-Px), were determined. Pyruvate-kinase (PK) activity was also considered as a predictable index of the age and constancy of the erythrocyte population. A steady, significant increase in GSH-Px and CAT enzyme activities was found. No significant variations were found in SOD and PK enzyme levels. These findings clearly suggest that the use of combined oral contraceptives leads to an increase in antioxidant defenses. The specific physiological and biochemical mechanisms of this response merit further investigation.

Bone mineral and aluminum concentrations in patients undergoing CAPD.

CAPD results in continuous peritoneal transfer of hormones and minerals involved in the pathogenesis of renal osteodystrophy (RO). Moreover, although CAPD patients seem to have better control of serum phosphate concentration than hemodialysis patients, the need for aluminum-containing phosphate binders (ACPB) may still be present. In a prospective study meant to investigate the evolution of RO, we obtained 79 bone biopsies in 29 uremic patients (20 male, 9 female; age 25-59, mean 46). Of these, 22 were obtained at the beginning of treatment, 24 after 24 months, 23 after 36 months and 10 after 60 months. All patients were treated with CAPD (Viaflex, Baxter 2-2.5 L x 4-5 bags/day; Ca(++) + 3.5, Mg(++) 1.5 mEq/L) as the first modality of therapy and received oral calcitriol, aluminum hydroxyde and/or calcium carbonate and magnesium hydroxyde in order to maintain serum calcium (Ca) and phosphorus within the normal range. Qualitative bone histology, bone Ca and magnesium (Mg) (Flame atomic absorption spectroscopy) and aluminum (Al) concentration (Graphite furnace atomic absorption spectrometry) were determined. CAPD achieves a good control of RO as indicated by the tendency toward a decreased incidence of mixed osteodystrophy and predominant hyperparathyroid bone disease and improvement of osteoid lesions. A defective Ca content of bone is persistent in the observed period and positively correlated to bone Mg concentration. An increased level of Al was shown in the serum and bone. The highest bone Al content was found among patients with predominant osteoid bone disease. Also in CAPD, patients consuming ACPB are at risk of bone Al accumulation despite the low Al levels in the dialysate.

Characteristics and functional properties of red cells during the first days of life.

In order to evaluate postnatal red blood cell (RBC) properties and whole-blood rheology, 36 healthy full-term newborn infants were tested twice (cord blood, 4th-day blood) for whole-blood flow rate, hematocrit, hemoglobin (Hb), RBC count, mean corpuscular volume, mean corpuscular Hb and its concentration, white blood cell and platelet count, plasma fibrinogen, erythrocyte glucose-6-phosphate dehydrogenase, glutathione peroxidase (GSH-Px), glutathione reductase, catalase and superoxide dismutase. Another 38 healthy full-term newborns were tested twice for separation of erythrocytes into fractions of different density. Healthy adults were taken as control. The results showed a decreased whole-blood flow rate in blood drawn on the 4th day with respect to cord blood. A multivariate analysis with flow rate as dependent variable demonstrated a significant positive correlation with GSH-Px on the 4th day. The assays of RBC densities showed a significant increase in the first 4 days.

Epidemiologic study of neonatal jaundice. A survey of contributing factors.

In the attempt to detect factors influencing bilirubinemia in healthy full-term or near-term newborn infants, a statistical analysis was carried out on a population of 1,126 neonates to study the variables possibly associated with maximum bilirubin values reached in the first days of life. The following variables were studied: maximum bilirubin level (maxBIL), sex, mode of delivery, gestational age, birthweight, ratio of birthweight/weight on 5th day, Apgar score, Rh and ABO incompatibility. Blood glucose and calcium levels, haematocrit, intake of breast milk, formula and glucose solution were also evaluated during the first 5 days of life. Higher maxBIL was found in males compared to females, after spontaneous delivery vs. emergency caesarean section, after caesarean section without fetal distress vs. emergency caesarean section, and in ABO incompatibility vs. no ABO incompatibility. Statistically significant inverse correlations were observed between maxBIL and gestational age, birth weight, blood glucose, and SE-calcium. Significant positive correlations were found between maxBIL and haematocrit and breast milk intake. A multiple regression analysis between maxBIL and the significantly correlated parameters showed that only gestational age and birth weight remained significantly correlated with maxBIL. The results of the present investigation confirm that the factors most commonly reported as being responsible for neonatal hyperbilirubinemia do in fact play a role, although it can be considered almost negligible with the exception of gender, mode of delivery, ABO incompatibility, birthweight and gestational age.

Changes in erythrocyte properties during the first hours of life: electron spin resonance of reacting sulfydryl groups.

In an attempt to clarify the mechanism by which the red cells (RBC) of newborn infants are protected against oxidative agents, electron spin resonance (ESR) assays were carried out using the nitroxide radical 4-maleimide-2,2,6,6-tetramethylpiperidinyl-1-oxyl (Mal-6), a sulfydryl-reacting agent. The ESR assays were performed in 24 samples of cord blood, 20 samples of blood from 4-day-old infants, and eight samples of 8-h-old infants. The analyses were carried out on whole blood and washed erythrocytes were resuspended in buffered saline. The same experiments were performed in 10 blood samples from healthy adults as controls. Whole blood, before and after removing the buffy coat, and cell-free plasma were also examined by ESR assay. Cell-free plasma and buffy coats proved not to be appreciably involved in the Mal-6 behavior. The data of the ESR spectroscopy demonstrated a significantly slower reaction rate in the samples of cord blood and in blood of 8-h-old infants, compared to that of 4-day-old infants and adults. No significant differences in Mal-6 behavior could be detected between cord blood and 4-day-old infant blood in the results of ESR assays performed in washed red cells. Chemical determination of RBC-reacting sulfydryl groups and the assays of glutathione also demonstrated the absence of differences between cord blood and blood of 4-day-old infants. The results of our investigation suggest that the RBC-sulfydryl-reacting groups are less involved in the detoxification of oxidative agents during the first hours of life than in the following days.(ABSTRACT TRUNCATED AT 250 WORDS)

Neonatal hyperbilirubinemia. Evidence for a role of the erythrocyte enzyme activities involved in the detoxification of oxygen radicals.

Determinations of erythrocyte enzyme scavengers of oxygen radicals (glutathione-peroxidase, superoxide-dismutase and catalase) and determinations of erythrocyte age-dependent glycolytic activities (glucose-6-phosphate-dehydrogenase, pyruvate-kinase and glucose-phosphate-isomerase) were carried out in cord blood and in the blood taken on the 4th day of life in 152 newborn infants with different peak bilirubin levels. The enzyme activities scavenging oxygen radicals, glutathione-peroxidase and superoxide-dismutase were significantly lower in infants with peak bilirubinemia higher than 214 mumol/l, compared to less-jaundiced neonates, both at birth and on the 4th day of life; their values correlated negatively with peak bilirubinemia at birth and on the 4th day of life. Glycolytic age-dependent enzyme activities were significantly higher in more jaundiced newborn infants only on the 4th day of life, when their values correlated positively with peak bilirubinemia. The results of this investigation suggest that a deficiency of factors protecting from oxygen toxicity, may play a role in the development of neonatal hemolysis and jaundice.