Transvaginal three-dimensional ultrasound assessment of Sylvian fissures at 18-30 weeks' gestation.

OBJECTIVE: To (1) evaluate the normal development of the Sylvian fissures in the anterior coronal view of the fetal brain at 18-30 weeks' gestation by transvaginal three-dimensional (3D) ultrasound, (2) develop reference ranges of measurements of the right and left Sylvian fissure angles during normal pregnancy at 18-30 weeks' gestation, and (3) examine intra- and interobserver repeatability of measurements of the right and left Sylvian fissure angles. METHODS: This was a prospective cross-sectional study of 422 women with a singleton pregnancy attending an ultrasound-based research clinic between March and December 2017. The entry criteria for the study were appropriately grown live fetus with no suspected structural and/or chromosomal defects between 18 + 0 and 30 + 6 weeks' gestation. Normal development of the Sylvian fissures was assessed in the anterior coronal plane of the fetal brain using transvaginal 3D volume multiplanar imaging. The coronal view was visualized as a single image from the three orthogonal views. Subsequently, the right and left Sylvian fissure angles were measured between a horizontal reference line (0°) and a line drawn along the upper side of the respective Sylvian fissure. Intra- and interobserver repeatability of the Sylvian fissure angle measurements was assessed by Bland-Altman plots. Reference equations were constructed for right and left Sylvian fissure angles for gestational age (GA) and head circumference (HC) using the Generalized Additive Models for Location Scale and Shape package. RESULTS: In the anterior coronal view of the fetal brain, an inward rotation of the upper portion of the Sylvian fissures was observed during the second and third trimesters of pregnancy. There was a significant negative polynomial association between the Sylvian fissure angles and GA and HC. Both Sylvian fissure angles crossed the reference line (zero), going from positive to negative, at around 25 weeks' gestation or at HC of 22 cm. Z-score difference between the smoothed percentiles of the right and left Sylvian fissure angles indicated that median, 10th and 90th smoothed percentiles were closest and almost the same for the GA-based references between 18 and 28 weeks and for the HC-based references between 14 and 24 cm. The intraclass correlation coefficient of the right and left Sylvian fissure angle measurements between the two sonographers was excellent at 0.993 (95% CI, 0.988-0.996) and 0.991 (95% CI, 0.985-0.995), respectively. On Bland-Altman analysis, the mean difference between the two sonographers in right Sylvian fissure angle measurement was 0.4° (95% CI, -10.2 to 10.1°) and in left Sylvian fissure angle it was 1.0° (95% CI, -9.6 to 11.6°). CONCLUSIONS: Assessment of the Sylvian fissure angles is highly reproducible. Sylvian fissure angle reference charts can serve as a screening tool for malformations of cortical development, guiding subsequent follow-up and referral for fetal brain magnetic resonance imaging and/or assessment by an expert neurosonologist. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Alendronate does not prevent long bone fragility in an inactive rat model.

The lack of estrogen and inactivity are both important in the pathogenesis of osteoporosis in elderly women, and there have been no appropriate rodent studies to examine the effects of common bisphosphonates on these two components separately. We compared the efficacy of alendronate (ALN) on the long bones of aged female rats, which were sedentary, estrogen deficient, or both. The rats were either forced to remain in a sitting position or allowed to walk in standard cages with or without ALN administration. The 8-week experimental period began 5 weeks after ovariectomy or sham surgery. Parameters of the hindlimb bones were determined by a three-point bending test, peripheral quantitative computed tomography, microfocus computed tomography, confocal laser Raman microspectroscopy, and dynamic histomorphometry. Regardless of ovariectomy, ALN was ineffective against the deterioration of breaking stress caused by sitting even though the trabecular bone mineral density was significantly higher in the sitting-ALN groups. Toughness was significantly deficient in the ovariectomy sitting-ALN group. This was in agreement with the bone geometry with a greater marrow space. Sitting also increased the mineral-to-matrix ratio and the carbonate-to-phosphate ratio, both indicative of aged bone. A greater loss of proteinaceous amide intensity compared with mineral intensity resulted in an increased mineral-to-matrix ratio in the presence of ALN. Sitting resulted in deficits in the quality and the geometry of cortical bone, resulting in fragility. The use of bisphosphonates, such as ALN, may provide a therapy best suited for osteoporotic individuals whose daily activity is not limited.

Observation of self-binding in monolayer 3He.

We report clear experimental signatures of the theoretically unexpected gas-liquid transition in the first three monolayer systems of (3)He adsorbed on graphite. The transition is inferred from the linear density dependence of the gamma coefficient of the heat capacity measured in the degenerate region (2≤T≤80 mK) below a critical liquid density (ρ(c0)). Surprisingly, the measured ρ(c0) values (0.6-0.9 nm(-2)) are nearly the same for all these layers in spite of their quite different environments. We conclude that the ground state of (3)He in strictly two dimensions is not a dilute quantum gas but a self-bound quantum liquid with the lowest density ever found.

Regulation of mechanical stress-induced MMP-13 and ADAMTS-5 expression by RUNX-2 transcriptional factor in SW1353 chondrocyte-like cells.

OBJECTIVE: To investigate the mechanism of mechanical stress-induced expression and regulation of aggrecanases and examine the role of runt-related transcription factor 2 (RUNX-2) in chondrocyte-like cells. METHODS: SW1353 cells were seeded onto stretch chambers at a concentration of 5×104 cells/chamber, and a uni-axial cyclic tensile strain (CTS) (0.5 Hz, 10% stretch) was applied for 30 min. Total RNA was extracted, reverse transcribed, and analyzed by polymerase chain reaction (PCR) and real-time PCR. RUNX-2 overexpression and small interfering RNA (siRNA) targeting RUNX-2 were used to investigate the role of RUNX-2 in CTS-induced gene expression. The involvement of diverse mitogen-activated protein kinase (MAPK) pathways in the activation of RUNX-2, MMP-13 and ADAMTS-5 during CTS was examined by Western blotting. RESULTS: CTS induced expression of RUNX-2, MMP-13, ADAMTS-4, -5, and -9. Overexpression of RUNX-2 up-regulated expression of MMP-13 and ADAMTS-5, whereas RUNX-2 siRNA resulted in significant down-regulation of mechanically-induced MMP-13 and ADAMTS-5 expression. CTS induced activation of p38 MAPK, and CTS induction of RUNX-2, MMP-13 and ADAMTS-5 mRNA was down-regulated by the selective p38 MAPK inhibitor SB203580 but not by the p44/42 MAPK inhibitor U0126, or the JNK MAPK inhibitor JNK inhibitor II. CONCLUSIONS: RUNX-2 might have a role as a key downstream mediator of p38's ability to regulate mechanical stress-induced MMP-13 and ADAMTS-5 expression.

An autosomal locus controls sex reversal in interspecific XY hybrids of the medaka fishes.

Although the two medaka species Oryzias latipes and O. curvinotus share the sex-determining gene Dmy, XY sex reversal occurs in interspecific hybridization between O. latipes females of the Hd-rR inbred strain and O. curvinotus males. In this Hd-rR-curvinotus mating, all XX and XY hybrids developed as females. In this study, we used another O. latipes inbred strain (HNI) for the mating, and found that 23% of XY hybrids developed as males, although all XX and the remaining XY hybrids developed as females. Linkage analysis using 236 XY hybrid males obtained from (Hd-rR × HNI) F(1) females showed that a single major locus, Hybrid maleless (Hml), on autosomal linkage group 17, contributed to the strain difference in the XY sex reversal. Furthermore, we found that crossing females of a different O. latipes inbred strain, HO4C, did not cause XY sex reversal in the interspecific hybrids, and that the XY hybrids from (Hd-rR × HO4C) F(1) females showed a 1:1 sex ratio. XY hybrid males had the HO4C allele at sequence-tagged site loci around the Hml locus whereas XY females had the Hd-rR allele, confirming the strong contribution of this locus to XY sex reversal. Reverse transcriptase PCR analysis showed a reduced expression of Dmy(curvinotus) in XY fry of the Hd-rR-curvinotus hybrids at hatching. These results suggest that the Hd-rR allele at the Hml locus interfere with the function of Dmy(curvinotus) on a hybrid background, thus resulting in XY sex reversal.

Plasma resistin concentration determined by common variants in the resistin gene and associated with metabolic traits in an aged Japanese population.

AIMS/HYPOTHESIS: Resistin is a cytokine derived from adipose tissue and is implicated in obesity-related insulin resistance and type 2 diabetes mellitus. Polymorphisms of the resistin gene (RETN) have been shown to affect the plasma resistin concentration. The aims of this study were to identify polymorphisms of RETN that influence plasma resistin concentration and to clarify the relation between plasma resistin level and metabolic disorders in an aged Japanese cohort. METHODS: The study participants comprised 3133 individuals recruited to a population-based prospective cohort study (KING study). Plasma resistin concentration, BMI, abdominal circumference, blood pressure, fasting plasma glucose and serum insulin concentrations, HbA(1c) content and serum lipid profile were measured in all participants. The HOMA index of insulin resistance (HOMA-IR) was also calculated. Eleven polymorphisms of RETN were genotyped. RESULTS: A combination of ANOVA and multiple linear regression analysis in screening and large-scale subsets of the study population revealed that plasma resistin concentration was significantly associated with rs34861192 and rs3745368 polymorphisms of RETN. Multiple linear regression analysis with adjustment for age and sex also showed that the plasma resistin level was significantly associated with serum concentrations of HDL-cholesterol, triacylglycerol and insulin, as well as with BMI. CONCLUSIONS/INTERPRETATION: Our results implicate the rs34861192 and rs3745368 polymorphisms of RETN as robust and independent determinants of plasma resistin concentration in the study population. In addition, plasma resistin level was associated with dyslipidaemia, serum insulin concentration and obesity. TRIAL REGISTRATION: ClinicalTrials.gov NCT00262691.

Prior treatment with vitamin K(2) significantly improves the efficacy of risedronate.

UNLABELLED: Prior 8-week treatment with menatetrenone, MK-4, followed by 8-week risedronate prevented the shortcomings of individual drugs and significantly increased the strength of ovariectomized ICR mouse femur compared to the ovariectomized (OVX) controls. Neither MK-4 following risedronate nor the concomitant administration may be recommended because they brought the least beneficial effect. INTRODUCTION: The objective of this study was to determine the best combinatory administration of risedronate at 0.25 mg/kg/day (R) with vitamin K(2) at approximately 100 microg MK-4/kg/day (K) to improve strength of osteoporotic mouse bone. METHODS: Thirteen-week-old ICR mice, ovariectomized at 9-week, were treated for 8 weeks with R, K, or R plus K (R/K), and then, either the treatment was withdrawn (WO) or switched to K or R in the case of R and K. After another 8 weeks, the mice were killed, and mechanical tests and analyses of femur properties by peripheral quantitative computed tomography, microfocus X-ray tube computed tomography, and confocal laser Raman microspectroscopy were carried out. RESULTS: The K to R femur turned out superior in parameters tested such as material properties, bone mineral density, BMC, trabecular structure, and geometry of the cortex. The increased cross-sectional moment of inertia, which occurred after K withdrawal, was prevented by risedronate in K to R. In addition to K to R, some properties of R to WO diaphysis and K to WO epiphysis were significantly better than OVX controls. CONCLUSION: Prior treatment with MK-4 followed by risedronate significantly increased femur strength in comparison to the OVX controls.

Molecular identification of a eukaryotic, stretch-activated nonselective cation channel.

Calcium-permeable, stretch-activated nonselective cation (SA Cat) channels mediate cellular responses to mechanical stimuli. However, genes encoding such channels have not been identified in eukaryotes. The yeast MID1 gene product (Mid1) is required for calcium influx in the yeast Saccharomyces cerevisiae. Functional expression of Mid1 in Chinese hamster ovary cells conferred sensitivity to mechanical stress that resulted in increases in both calcium conductance and the concentration of cytosolic free calcium. These increases were dependent on the presence of extracellular calcium and were reduced by gadolinium, a blocker of SA Cat channels. Single-channel analyses with cell-attached patches revealed that Mid1 acts as a calcium-permeable, cation-selective stretch-activated channel with a conductance of 32 picosiemens at 150 millimolar cesium chloride in the pipette. Thus, Mid1 appears to be a eukaryotic, SA Cat channel.

Abnormal expression of TIMP-2, SOD, vimentin and PAI proteins in cloned bovine placentae.

Cloned mammals suffer from high rates of placental abnormality and foetal loss during pregnancy. We previously used 2-D gel electrophoresis and mass spectrometry for global proteomic analysis of cloned and normal bovine placentae to identify differential protein expression patterns. Here, we used Western blot analysis to confirm the expression levels of several pregnancy-related proteins putatively identified as being differentially expressed in somatic cell nuclear transfer (SCNT) vs normal bovine placentae. The expression levels of tissue inhibitor of metalloproteinase-2 (TIMP-2), its downstream protein, matrix metalloproteinase-2 (MMP-2), superoxide dismutase (SOD), vimentin and plasminogen activator inhibitor-1 (PAI) were analysed in the placentae of SCNT cloned Korean native cattle that died immediately after birth and in normal placentae obtained by AI. Our results revealed that TIMP-2 and SOD were up-regulated in SCNT placenta compared with normal placenta, whereas MMP-2 levels were comparable in cloned and normal placentae, and vimentin and PAI were significantly down-regulated in SCNT compared with normal placentae. Our results suggest that key proteins of placental development are abnormally expressed in SCNT cloned bovine placentae, probably resulting in abnormal placental function and clonal mortality.

Examination of signalling pathways involved in muscarinic responses in bovine ciliary muscle using YM-254890, an inhibitor of the Gq/11 protein.

BACKGROUND AND PURPOSE: In the ciliary muscle, the tonic component of the contraction produced by cholinergic agonists is highly dependent on Ca2+ provided by influx through non-selective cation channels (NSCCs) opened by stimulation of M3 muscarinic receptors. We examined effects of YM-254890 (YM), a Gq/11-specific inhibitor, on contraction, NSCC currents and [Ca2+]i elevation induced by carbachol (CCh). EXPERIMENTAL APPROACH: Isometric tension was recorded from ciliary muscle bundles excised from bovine eyes. In ciliary myocytes dispersed with collagenase and cultured for 1-5 days, whole-cell currents were recorded by voltage clamp and the intracellular free Ca2+ concentration [Ca2+]i was monitored using the Fluo-4 fluorophore. Existence and localization of M3 receptors and the alpha subunit of Gq/11 (Galpha(q/11)) were examined by immunofluorescence microscopy using AlexaFluor-conjugated antibodies. KEY RESULTS: Both phasic and tonic components of contractions evoked by 2 microM CCh were inhibited by YM (3-10 microM) in a dose-dependent manner. In the cultured cells, CCh (0.05-10 microM) evoked an NSCC current as well as an elevation of the [Ca2+]i. Both initial and sustained phases of these CCh-evoked responses were abolished by YM (3-10 microM). Immunostaining of the cytoplasmic side of the plasma membrane of ciliary myocytes revealed a dense distribution of M3 receptors and Galpha(q/11). CONCLUSIONS AND IMPLICATIONS: The tonic as well as phasic component of the ciliary muscle contraction appears to be under control of signals conveyed by a G(q/11)-coupled pathway. YM is a useful tool to assess whether Gq/11 is involved in a signal transduction system.

The medaka rs-3 locus required for scale development encodes ectodysplasin-A receptor.

The bodies of most teleost fish species are covered with specialized subepithelial structures known as scales. The scale is an epithelial appendage that differentiates from the dermal mesenchyme. Mammals, on the other hand, have no scales, but instead their bodies are covered with hair. Although their appearances are quite different, scales and hair can be considered structurally similar in that both of them are epithelial appendages distributed over the body surface in an orderly pattern. This analogy suggests that they may have the same evolutionary origin. But, to date, no molecular evidence has been presented that links scales and hair. A mutation at the rs-3 locus of medaka (Oryzias latipes) leads to almost complete loss of scales. We demonstrated that the rs-3 locus encodes ectodysplasin-A receptor (EDAR), which is required for the initiation of hair development in mammals. We identified a novel transposon inserted in the first intron of EDAR, which causes aberrant splicing. This work shows that EDAR is required for scale development in fish and suggests that it is an evolutionarily conserved molecule that is required for the development of epithelial appendages in vertebrates.

Renal complications in two patients with dentatorubral-pallidoluysian atrophy.

Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder characterized by various combinations of myoclonus epilepsy, ataxia, choreoathetosis and dementia. No specific therapy has been established and renal complication is rare. We report two cases of DRPLA with renal complications. Hematuria and proteinuria had gradually progressed for 2 and 13 years in these patients. Renal biopsy findings revealed focal glomerulosclerosis in one case and end-stage kidney disease in the other case. Angiotensin-converting enzyme inhibitor and angiotensin receptor II antagonist were administered to both patients, resulting in improved proteinuria and preserved renal function in one patient, while renal function continued to deteriorate in the other patient. Although renal complication is rare in patients with DRPLA, the presence of renal disease has to be suspected in patients with persistent proteinuria.

Brief exposure to cycloheximide prior to electrical activation improves in vitro blastocyst development of porcine parthenogenetic and reconstructed embryos.

To investigate the effects of cycloheximide exposure before electrical activation of in vitro-matured porcine oocytes on the subsequent development of parthenogenetic embryos, cumulus-free mature oocytes were exposed to NCSU-23 medium containing cycloheximide (10 microg/mL) for 0, 5, 10, 20, 30 and 60 min, activated by electrical pulse treatment (1.5 kV/cm, 100 micros) and then cultured in PZM-3 for 7 days. To evaluate the effects of cycloheximide on the activation of nuclear transfer embryos, reconstructed embryos were electrically activated by two DC pulses (1.2 kV/cm, 30 micros) before or after exposure to cycloheximide. The reconstructed embryos were allocated into four groups: electrical pulse treatment alone (Ele); exposure to cycloheximide for 10 min followed by electrical activation (CHX+Ele); electrical activation followed by exposure to cycloheximide for 6h (Ele+CHX); exposure to cycloheximide for 10 min, followed by electrical activation and a further exposure to cycloheximide for 6h (CHX+Ele+CHX). The activated reconstructed embryos were cultured in PZM-3 for 6 days. Oocytes treated with 10 min exposure to cycloheximide followed by electrical activation had a significantly higher percentage of blastocyst formation compared to control oocytes and oocytes exposed for > or =30 min. In the reconstructed embryos, the blastocyst development rates of embryos exposed to cycloheximide (CHX+Ele, Ele+CHX and CHX+Ele+CHX) were significantly higher than those of the control group (Ele). Among the cycloheximide-treated groups, the CHX+Ele group had increased development rate and total blastocyst cell number, though these values were not significantly different from those observed in the other cycloheximide-treated groups. To evaluate the quality of NT embryos treated with cycloheximide, apoptosis in blastocysts was analyzed by TUNEL assay. The 10 min exposure to cycloheximide prior to electrical activation significantly reduced cell death compared with longer exposure to cycloheximide after electrical fusion. In conclusion, brief exposure to cycloheximide prior to electrical activation may increase the subsequent blastocyst development rates in porcine parthenogenetic and reconstructed embryos.

Effects of bepridil on stretch-activated BKca channels and stretch-induced extrasystoles in isolated chick hearts.

Various types of mechanosensitive ion channels, including cationic stretch-activated channels (SAC(NS)) and stretch-activated BKca (SAKca) channels, modulate heart rhythm. Bepridil has been used as an antiarrhythmic drug with multiple pharmacological effects; however, whether it is effective for mechanically induced arrhythmia has not been well investigated. To test the effects of Bepridil on SAKca channels activity, cultured chick embryonic ventricular myocytes were used for single-channel recordings. Bepridil significantly reduced the open probability of the SAKca channel (P(O)). Next, to test the effects of bepridil on stretch-induced extrasystoles (SIE), we used an isolated 2-week-old Langendorff-perfused chick heart. The left ventricle (LV) volume was rapidly changed, and the probability of SIE was calculated in the presence and absence of bepridil, and the effect of the drug was compared with that of Gadolinium (Gd(3+)). Bepridil decreased the probability of SIE despite its suppressive effects on SAKca channel activity. The effects of Gd(3+), which blocks both SAKca and SAC(NS), on the probability of SIE were the same as those of bepridil. Our results suggest that bepridil blocks not only SAKca channels but possible also blocks SAC(NS), and thus decreases the stretch-induced cation influx (stabilizing membrane potential) to compensate and override the effects of the decrease in outward SAKca current (destabilizing membrane potential).

Both focal adhesion kinase and c-Ras are required for the enhanced matrix metalloproteinase 9 secretion by fibronectin in ovarian cancer cells.

Cell adhesion to the extracellular matrix appears to trigger a cascade of intracellular signalings. We have shown previously that treatment of ovarian cancer cells with peritoneal conditioned medium or purified fibronectin (FN) activated matrix metalloproteinase 9 secretion and, thereby, cancer cell invasion. By use of antisense oligonucleotides to focal adhesion kinase (FAK) and a dominant-negative mutant of ras (S17Nras), we found that both FAK and c-Ras were required for the activation of matrix metalloproteinase 9 secretion by FN. In addition, both antisense oligonucleotides to FAK and S17Nras inhibited mitogen-activated protein kinase activation by FN treatment, suggesting the involvement of mitogen-activated protein kinase in the FN-dependent signaling.

Pp125FAK is required for stretch dependent morphological response of endothelial cells.

In this study, critical signaling pathway required for the stretch induced morphological changes of human umbilical endothelial cells (HUVECs) was investigated. Uniaxial cyclic stretch (1 Hz, 20% in length) of the cells cultured on an elastic silicon membrane induced a gradual morphological change in the cells from a polygonal shape to an elongated spindle-like shape whose long axis was aligned perpendicular to the stretch axis. We found that protein tyrosine phosphorylation of cellular proteins increased and peaked at 20 min in response to cyclic stretch. Either treatment of cells with gadolinium (Gd3+), a potent blocker for stretch-activated channels, or removal of extracellular Ca2+ blocked the tyrosine phosphorylation of the proteins, suggesting that stretch-activated (SA) ion channels regulated stretch specific tyrosine phosphorylation. The major phosphorylated proteins had molecular masses of approximately 120-135 kDa, and 70 kDa. Immunoprecipitation experiments revealed that paxillin, focal adhesion kinase (pp125FAK) and pp130CAS were included in the 70 kDa and 120-135 kDa bands, respectively. The morphological change was inhibited by herbimycin A and genistein, inhibitors of tyrosine kinases, suggesting that tyrosine phosphorylation was required for the morphological change. In addition, the kinase activation of pp125FAK was observed in response to cyclic stretch. Moreover, suppression of pp125FAK expression by the antisense phosphorothioate oligodeoxynucleotides (S-ODN) in HUVECs resulted in inhibition of tyrosine phosphorylation of paxillin and the stretch-dependent morphological changes. These results suggest that an activation of tyrosine kinase(s) by an increase in intracellular Ca2+ and pp125FAK play a critical role in the unique morphological change specifically observed in endothelial cells subjected to uni-axial cyclic stretch.

Induction of endothelin-1 expression by glucose: an effect of protein kinase C activation.

Enhanced actions or levels of endothelin-1 (ET-1), a potent vasoconstrictor, have been associated with decreased blood flow in the retina and peripheral nerves of diabetic animals and may be related to the development of pathologies in these tissues. Hyperglycemia has been postulated to increase ET-1 secretion in endothelial cells. We have characterized the mechanism by which elevation of glucose is increasing ET-1 mRNA expression in capillary bovine retinal endothelial cells (BREC) and bovine retinal pericytes (BRPC). Elevation of glucose, but not mannitol, from 5.5 to 25 mmol/l for 3 days increased membranous protein kinase C (PKC) activities and ET-1 mRNA in parallel levels by 2-fold in BREC and BRPC. These effects were reversed by decreasing glucose levels to 5.5 mmol/l for an additional 2 days. Glucose-induced ET-1 overexpression was inhibited by a general PKC inhibitor, GF109203X, and a mitogen-activated protein kinase kinase inhibitor, PD98059, but not by wortmannin, a phosphatidylinositol 3-kinase inhibitor. By immunoblot analysis, PKC-beta2 and -delta isoforms in BREC were significantly increased relative to other isoforms in the membranous fractions when glucose level was increased. Overexpression of PKC-beta1 and -delta isoforms but not PKC-zeta isoform by adenovirus vectors containing the respective cDNA enhanced in parallel PKC activities, proteins, and basal and glucose-induced ET-1 mRNA expression by at least 2-fold. These results showed that enhanced ET-1 expression induced by hyperglycemia in diabetes is partly due to activation of PKC-beta and -delta isoforms, suggesting that inhibition of these PKC isoforms may prevent early changes in diabetic retinopathy and neuropathy.

Effects of beraprost sodium and insulin on the electroretinogram, nerve conduction, and nerve blood flow in rats with streptozotocin-induced diabetes.

The effect of a prostacyclin analog, beraprost sodium, on the electroretinogram, motor nerve conduction velocity, and nerve blood flow was determined in rats with streptozotocin-induced diabetes and was compared with the effect of insulin. Beraprost sodium (0.01 mg x kg-1 x day-1 for 8 weeks) significantly shortened the peak latency of the electroretinogram b-wave, increased tail nerve conduction velocity, and increased sciatic nerve blood flow in diabetic rats (P < 0.0003, 0.0001, and 0.0001 vs. untreated diabetic rats, respectively). This was accompanied by a significant increase in the 6-keto-prostaglandin F1alpha content of the thoracic aorta and a marked increase in the cAMP content of the sciatic nerve. Beraprost sodium had no effect on the sorbitol and fructose contents of the sciatic nerve and retina, but insulin (8-10 U/day) significantly reduced both parameters. These findings suggest that beraprost sodium may be useful for prevention of vascular and neural dysfunction in the retina and peripheral nerve.

A protein kinase C-beta-selective inhibitor ameliorates neural dysfunction in streptozotocin-induced diabetic rats.

Increased protein kinase C (PKC) activity has been implicated in the pathogenesis of diabetic retinopathy and nephropathy. However, the role of PKC in diabetic neuropathy remains unclear. The present study was conducted to compare the effect of PKC inhibition by a PKC-beta-selective inhibitor, LY333531 (LY), on diabetic nerve dysfunction with that of an aldose reductase inhibitor, NZ-314 (NZ). Streptozotocin-induced diabetic rats were treated with or without LY and/or NZ for 4 weeks, and motor nerve conduction velocity (MNCV), coefficient of variation of R-R interval (CVR-R), sciatic nerve blood flow (SNBF), peak latencies of oscillatory potentials on electroretinogram, PKC activities in membranous and cytosolic fractions of sciatic nerves, and polyol contents in the tail nerves were measured. Untreated diabetic rats demonstrated delayed MNCV, decreased CVR-R, reduced SNBF, and prolonged peak latencies of oscillatory potentials. Treatment with LY as well as NZ prevented all these deficits in diabetic rats. There were no significant differences in PKC activities in membranous or cytosolic fractions of sciatic nerves between normal and diabetic rats. Treatment with neither LY nor NZ altered PKC activities. Nerve myo-inositol depletion in diabetic rats was ameliorated not only by NZ, but also by LY. These observations suggest that inhibition of PKC-beta by LY may have a beneficial effect in preventing the development of diabetic nerve dysfunction, and that this effect may be mediated through its action on the endoneurial micro-vasculature.