Low-temperature heat capacities of confined liquid benzene, implying the behavior of ordinary bulk liquids.

Isobaric heat capacities C p of benzene confined in silica MCM-41 mesopores with average diameters equal to and smaller than 2.9 nm were measured by precise adiabatic calorimetry. The confined benzene samples revealed no thermal anomaly due to crystallization/fusion and vitrified at low temperatures. The C p curves displayed a hump and a considerably quick decrease on the low-temperature side of the hump as the pore diameter increased. The enthalpy-relaxation effects observed on intermittent heating showed that the anomaly of the C p hump and quick decrease is not assigned to a glass transition. The bend in the temperature dependence of density reported previously was interpreted as corresponding to the quick decrease in C p . We concluded that the anomalous C p and density behaviors originated from the ordering/excitation in the configurational state, close to the ground state, of confined molecular aggregate and proposed a scenario that explains the general C p curves of ordinary bulk supercooled liquids in equilibrium at low temperatures below the glass-transition temperatures.

Hydroxylamine-doping effect on the Tg of 160 K for water confined in silica-gel nanopores.

The glass transition behavior of hydroxylamine (HA) aqueous solutions in bulk and confined in silica-gel nanopores with average width of 1.1 nm was studied by means of differential scanning calorimetry measurements and adiabatic calorimetry. The glass transition temperature (Tg) of the confined solution with high HA mole-fraction (xHA) was essentially the same as the value of the bulk. This suggests that the nano-size confinement affects the Tg of HA aqueous solution little. Meanwhile, the bulk solution with xHA < 0.3 revealed partial crystallization on cooling and, on the other hand, the confined solution with the same xHA did not crystallize. The Tg of the xHA = 0.076 confined solution was 174 K which is higher than the value of 160 K for pure water confined in the same silica-gel pores. This demonstrates that HA doping leads to no abrupt Tg-decrease, unlike doping of all the other second components reported so far, suggesting that HA is set neatly in a hydrogen-bond network formed by water molecules. We discuss the xHA dependence of Tg for the HA aqueous solutions from a viewpoint related to peculiar phase-behavior of pure water. Considering that the xHA = 0.076 aqueous solution revealed no anomaly compared with pure water, it was recognized as corresponding to the high-temperature phase of pure water.

Spin ordering and enhancement of electronic heat capacity in an organic system of (DI-DCNQI)(2)(Ag(1-x)Cu(x)).

Thermodynamic measurements on the organic system of (DI-DCNQI)(2)(Ag(1-x)Cu(x)) (x = 0,0.05, 0.71, 0.90) were performed to study the change from the charge-ordered (CO) insulating state to the π-d hybridized metallic state. A thermal anomaly associated with the antiferromagnetic transition that occurred in the charge-ordered lattice was observed at 6.2 K from the temperature dependence of the heat capacity of (DI-DCNQI)(2)Ag. We have found that the magnetic entropy around the peak is only 1.5% of Rln2, corresponding to the full entropy expected for the formula unit of (DI-DCNQI)(2)Ag. This anomaly is suppressed down to about 3 K in the x = 0.05 sample owing to the disorders induced in the CO lattice. In the metallic concentration of x = 0.90, the low-temperature electronic heat capacity coefficient, γ was found to be enhanced by up to about 63.6 mJ K(-2) mol(-1) probably owing to the cooperative effect of π-d hybridization and intersite Coulomb interaction (V).

Intrauterine growth in the offspring of epileptic women: a prospective multicenter study.

The aim of the present study was to evaluate the risk of intrauterine growth delay in the offspring of epileptic mothers and to quantify the risks of intrauterine exposure to antiepileptic drugs (AEDs). Data concerning 870 newborns, prospectively collected in Canada, Japan and Italy, using the same study design, were pooled and analyzed. The overall proportion of newborns whose body weight (7.8%) or head circumference (11.1%) at birth were below the 10th percentile was not increased. However, logistic regression analysis showed that the risk of small head circumference was significantly higher in Italian than in Japanese (RR 4.2; 95% CI: 2.2-8.0) or Canadian children (RR 2.6; 95% CI: 1.1-6.5), and in children exposed to polytherapy (RR 2.7; 95% CI: 1.2-6.3), phenobarbital (PB) (RR 3.6; 95% CI: 1.4-9.4) and primidone (PRM) (RR 4.5; 95% CI: 1.5-13.8). Country was also the only factor affecting low body weight, with Italian children having a higher risk than Japanese (RR 5.2; 95% CI: 2.6-10.4) or Canadian (RR 8.8; 95% CI: 2.0-38.1) children. Due to the small categories, the influence of AED doses and plasma concentrations was studied for each individual AED, without adjustment for the other potential confounding factors. A clear dose-dependent effect was found for PB and PRM in terms of both small head circumference and low body weight, and a concentration-dependent effect for PB in terms of small head circumferences. The size of the difference between the Italian and the other two populations, which is only partially explained by differences in therapeutic regimens, suggests that genetic, environmental and ethnic factors also need to be taken into account when considering possible explanations.

Congenital malformations due to antiepileptic drugs.

To identify the major risk factors for the increased incidence of congenital malformations in offspring of mothers being treated for epilepsy with antiepileptic drugs (AEDs) during pregnancy and, to determine the relative teratogenic risk of AEDs, we prospectively analyzed 983 offspring born in Japan, Italy, and Canada. The incidence of congenital malformations in offspring without drug exposure was 3.1%, versus an incidence with drug exposure of 9.0%. The highest incidence in offspring exposed to a single AED occurred with primidone (PRM; 14.3%), which was followed by valproate (VPA; 11.1%), phenytoin (PHT; 9.1%), carbamazepine (CBZ; 5.7%), and phenobarbital (PB; 5.1%). The VPA dose and level positively correlated with the incidence of malformations. This study first determined a cut-off value of VPA dose and level at 1000 mg/day and 70 microg/ml, respectively, to avoid the occurrence of malformations. The incidence of malformations increases as the number of drugs increases, and as the total daily dose increases. Specific combinations of AEDs such as VPA + CBZ and PHT + PRM + PB produced a higher incidence of congenital malformations. The incidence of malformations was not associated with any background factors studied except for the presence of malformations in siblings. These results indicate that the increased incidence of congenital malformations was caused primarily by AEDs, suggesting that malformations can be prevented by improvements in drug regimen, and by avoiding polypharmacy and high levels of VPA (more than 70 microg/ml) in the treatment of epileptic women of childbearimg age.

Calbindin-D 28 kD and parvalbumin in the horizontal cells of rat retina during development.

PURPOSE: Calbindin-D 28K (CaD) and parvalbumin (PV) are calcium-binding proteins thought to act as an intraneural calcium ion buffering system in the central nervous system. We previously reported that PV appears at birth in some cells in the outer portion of the nuclear layer of the retina that can differentiate into horizontal cells. CaD is also distributed in horizontal cells; however, it is not clear at which developmental stage CaD appears. METHODS: The development of horizontal cells and the distribution of CaD and PV was examined ultrastructurally and immunohistochemically in rat retinas from birth (P0) to postnatal day 50 (P50). RESULTS: Our ultrastructural data showed clear differentiation of horizontal cells from other retinal cells in the early postnatal days. These cells became nearly mature around P10 to P12. PV appeared in the outer nuclear layer at birth (P0) and, by P7, was observed in the ganglion cell layer, amacrine cells, and horizontal cells. CaD-immunoreactive cells, however, were not seen in any portions of the retina until P7. At P10, CaD-immunoreactivity was faintly observed in horizontal cells, and its immunoreactivity gradually increased in the horizontal cells from P10 to P15 when the eyes of the rats opened. CaD was not found in the ganglion cell layer or in amacrine cells at any period examined. CONCLUSION: In the horizontal cells, PV appeared when they were ultrastructurally distinguished from other retinal cells, while CaD appeared when they already had some structure for endocytosis and synaptic transmission, suggesting that PV and CaD may be good morphological and functional markers for horizontal cells, respectively.

Does light stimulus at eye opening of the developing rat influence retinal expression of GTP-binding protein (G(0))?

We previously hypothesized that light stimulus at eye opening of rats on postnatal days (P) 13 or 14 has an effect on the expression of GTP-binding proteins (G(0) in the retina) because the concentration of G(0) alpha increased rapidly between P10 and P15. This hypothesis was also supported by the findings that the distribution of G(0) alpha in the retina was almost the same as that of adult rats between P10 and P15. In this study, pregnant rats were kept in a dark room after vaginal plugs were identified; they gave birth to their pups in the dark, and their pups were reared by their mothers in the dark. The postnatal rats were sacrificed at P10, P15, P18, P22, P24, P27, and P30. Their retinas were investigated immunochemically and immunohistochemically, using G(0) alpha antibody, and these results were compared with those of the rat pups reared normally. Only G(0) alpha immunoreactivity in the inner nuclear layer of rats reared in the dark room was weaker than in the controls; the distribution of G(0) alpha in the retina did not change, as compared with pups reared in normal conditions. In addition, in pups reared in the dark, G(0) alpha increased rapidly from P10 to P15. However, the concentration of G(0) alpha in the retina of rat pups reared in the dark was significantly low at P22 (p < 0.01) and P30 (p < 0.05), as compared with pups reared in normal conditions. Although the function of G(0) in the retina may have something to do with the light stimulus after eye opening, it appeared that the expression of G(0) was not influenced by light stimulus at eye opening.

Choroidal osteoma in an infant.

PURPOSE: To report an 8-month-old infant with choroidal osteoma. METHOD: Case report. RESULTS: The patient, who had bilateral yellow stippling at the posterior pole, was followed up for 8 years. Both fundi developed creamy, irregular scalloped lesions. Computed tomography showed a bony plate at the posterior pole bilaterally. CONCLUSION: We believe that this is the youngest patient reported to have choroidal osteoma.

Ontogeny of GTP-binding proteins, Gi and G(o), in rat retina.

The distribution and the levels of Gi1 (plus Gi3), Gi2, and G(o) in rat retina were studied immunohistochemically and immunochemically during development. At embryonic day (E) 15, Gi1 alpha/Gi3 alpha was observed in the inner layer of the neural retina, the future nerve fiber layer (NFL), while Gi2 alpha was observed both in the inner and outer layers of the neural retina. No immunoreactivity for G(o) alpha was observed. At E18, Gi1 alpha/Gi3 alpha and Gi2 alpha appeared in the inner plexiform layer (IPL), while G(o) alpha was faintly immunoreactive only in the NFL. At birth, Gi2 alpha/Gi3 alpha and G(o) alpha appeared in the ganglion cell layer. Gi2 alpha was intensely immunoreactive in the NFL and IPL. At postnatal day (P) 10, the inner portions of the retina, from the NFL to the outer plexiform layer, were immunoreactive to Gi1 alpha/Gi3 alpha, Gi2 alpha, and G(o) alpha. Gi1 alpha/Gi3 alpha and G(o) alpha were distributed characteristically in a laminated pattern in the IPL, but Gi2 alpha was present homogeneously in the IPL. At P12, Gi2 alpha appeared in the outer nuclear layer. As the postnatal days advanced, the laminated pattern of immunoreactivity to G(o) alpha in the IPL became diffuse, but immunoreactivity to Gi1 alpha/Gi3 alpha remained. The results of enzyme immunoassays showed that the concentration of G(o) alpha increased rapidly from P10 to P15 and reached almost the adult level at P20-P30, while Gi2 alpha decreased until P15 and was almost constant thereafter. These results showed that the distribution of Gi1 alpha/Gi3 alpha, Gi2 alpha, and G(o) alpha differs during development, suggesting that each G protein in the developing retina has a unique function.

Chronic retinal effects by ultraviolet irradiation, with special reference to superoxide dismutases.

Recently ultraviolet light (UV) reaching the Earth's surface has been gradually increasing in amounts by the destruction of the ozone layers. Large parts of UV are absorbed in the cornea and lens, and only a few amounts reached the retina; however, the effect on the retina is not fully elucidated. 38 rats were irradiated 0.5-5.0 J/cm2 UV from 6 to 50 times every 24 hours, and immunohistochemically and immunochemically for superoxide dismutases (SOD). Morphologically, the destruction of rod outer segments (ROS) and dissociation of cell membranes between the pigment epithelial cells (PE) were already observed by 6 times 0.5 J/cm2 UV irradiations. As the doses of UV increased, heterochromatins and lipid droplets increased in the PE. In normal retina, Cu/Zn SOD were mainly distributed from the inner limiting membrane (ILM) to the ganglion cell layer, and the PE; however, after 6 times 0.5 J/cm2 UV irradiations, the distribution became widened from inner to outer plexiform layer (OPL). At that time, the concentrations of Cu/Zn and Mn SOD increased in the retina. The present study reveals that the morphological damage caused by UV irradiation is observed in the ROS and PE, where no immunoreactivities could be detected to Cu/Zn and Mn SOD. However, morphological damage was not from the ILM to OPL, where the immunoreactivities to both Cu/Zn and Mn SOD were observed.

Glutathione S-transferase M1 genotype and age-related cataracts. Lack of association in an Italian population.

PURPOSE: To investigate possible associations between the gene number and allelic forms of glutathione S-transferase M1 (GSTM1) and the occurrence of nucleic and cortical age-related cataracts. METHODS: Patients with cortical cataract, nuclear cataract, mixed and cortical cataract, and no cataract were sytematically selected from subjects evaluated in the Italian-American Study of the Natural History of Age-Related Cataract. The patients were typed for the A, B, and null alleles of GSTM1 using a variation of the amplification refractory mutation system. RESULTS: Forty-nine percent of patients (50/102) with cortical cataracts, 45% (13/29) with nuclear cataracts, 51% (36/71) with mixed nuclear and cortical cataracts, and 50% of controls (49/98) were homozygous for the null GSTM1 allele. Twenty-five percent of patients (26/102) with cortical cataracts, 24% (7/29) with nuclear cataracts, 31% with mixed nuclear and cortical cataracts, and 27% of controls (26/98) displayed only the A allele for GSTM1. Twenty-four percent of patients (24/102) with cortical cataract, 24% (7/29) with nuclear cataracts, 14% (10/71) with mixed nuclear and cortical cataract, and 18% of controls showed only the B allele for GSTM1. Two percent of patients (2/102) with cortical cataracts, 7% (2/29) with nuclear cataracts, 4% (3/71) with mixed nuclear and cortical cataracts, and 5% of controls (5/98) showed both A and B alleles for GSTM1. CONCLUSIONS: No associations between the GSTM1 alleles, including the null allele, and cataracts were detected in this study.

Immunohistochemical study of 28-kD heat shock protein in the lens of young human embryos.

The localization of 28-kD heat shock protein (HSP28) in the lenses of human embryos (Carnegie stages 13-21) was studied immunohistochemically using antibodies for HSP28. At stage 13, HSP28 was observed in the lens placode. At stage 15, when the lens vesicle is formed by the invagination of the lens placode, HSP28 was observed in the posterior portion of the lens vesicle. From stages 16 to 18, when the posterior portion of the lens epithelium elongates toward the anterior lens epithelium and forms the primary lens fiber, HSP28 was observed in the apical and basal sides of the primary lens fiber. At stage 19, when the primary lens fiber attaches to the anterior lens epithelium, immunoreactivity to HSP28 appeared in the anterior lens epithelium. At stage 21, the anterior lens epithelium and the equator portion of the lens, where the secondary lens fiber is formed, were intensely immunoreactive to HSP28. Although alpha B-crystallin is thought to be one of the small HSPs, the distribution of HSP28 in the lenses of human embryos was different from that of alpha B-crystallin which we previously reported.

Ultrastructure of developing muscle in the upper limbs of the human embryo and fetus.

BACKGROUND: The ultrastructure of the myogenesis, which proceeds along with the appearance of muscle-specific proteins and isozymes, has not been fully described in the upper limb of staged human embryos. METHODS: Eight human embryos (Carnegie stage 14-22) and two fetuses (11 and 12 weeks of gestation) were fixed with 5% glutaraldehyde, 4% paraformaldehyde, and 0.2% picric acid in 0.1 M phosphate buffer, pH 7.2. The upper limbs were dissected out and processed for transmission electron microscopy, and sections of the biceps brachii muscle were cut and examined. RESULTS: At stage 14, the myoblasts were loosely scattered in the ventral proximal region of the upper limb bud and had a small amount of cytoplasm with a few intracellular organelles. At stage 16, the myoblasts were spindle shaped and oriented parallel to the axis of the upper limb bud. These cells had irregularly shaped nuclei with prominent nucleoli, rough endoplasmic reticulum (ER), and mitochondria, but no myofilaments were observed. At stages 17-19, rough ER, free ribosomes, and mitochondria increased in number and thick and thin filaments with faint Z-lines appeared in the peripheral cytoplasm of the myotube. The plasma membranes of some neighboring myotubes were continuous, suggesting that these cells were in the initial stages of the fusion process. At stage 22, the striated pattern of the myofilaments became evident and tubular structures appeared around them and near the plasma membrane. In the fetus at the 11th week, the basal lamina began to surround the myotubes, and T-tubules with sarcoplasmic reticulum were observed. Dyads and triads were observed in the myotube of the 12th week fetus. CONCLUSION: These findings suggest that rapid myogenesis occurs during the late embryonic period in human upper limbs and that the ultrastructural characteristics of mature myotubes are established during the early fetal period.

Ontogeny of copper-zinc and manganese superoxide dismutase in the developing rat retina: immunohistochemical and immunochemical study.

The localization of copper-zinc and manganese superoxide dismutase (SOD) in the developing rat retina was studied immunohistochemically and immunochemically. Immunoreactivity to Cu/Zn SOD was observed in the inner limiting membrane, nerve fiber layer, ganglion cell layer (GCL) and pigment epithelium on postnatal day (P) 7. From P7 to at least 10 weeks, the distribution of Cu/Zn SOD remained unchanged in rats. From P15 to P30, the immunoreactivity to Mn SOD appeared in the GCL and inner plexiform layer. The distribution of Mn SOD remained unchanged between P30 and 10 weeks. Our immunochemical study revealed that the concentration of Cu/Zn SOD was higher than that of Mn SOD throughout the postnatal period. The differential distributions of Cu/Zn SOD in the developing rat retina support the hypothesis that Cu/Zn and Mn SOD play an important role in the protection against oxygen free radicals in the different layers of the retina throughout development.