Arg4810Lys mutation in RNF213 among Eastern Indian non-MMD ischemic stroke patients: a genotype-phenotype correlation

INTRODUCTION

RNF213 mutations have been reported mostly in moyamoya disease (MMD) with varying frequencies across different ethnicities. However, its prevalence in non-MMD adult-onset ischemic stroke is still not well explored.

AIMS AND OBJECTIVES

This present study thus aims to screen the most common RNF213 variant (Arg4810Lys, among East Asians) in the Eastern Indian non-MMD ischemic stroke patients and correlate it with long-term progression and prognosis of the patients. The subjects were analyzed for this variant using PCR-RFLP and confirmed using Sanger sequencing method.

RESULT AND CONCLUSION

We have identified Arg4810Lys variant among eleven young-onset familial ischemic stroke patients in heterozygous manner. A positive correlation of the variant with positive family history (P = 0.001), earlier age at onset (P = 0.002), and history of recurrent stroke (P = 0.015) was observed. However, the carriers showed better cognitive performances in memory (P = 0.042) and executive function (P = 0.004). Therefore, we can conclude that Arg4810Lys/RNF213 - a pathogenic variant for young-onset familial ischemic stroke with higher incidence of recurrent events unlike in MMD cases, have no additional impact on cognition among Eastern Indians.

Genetic Variations and Altered Blood mRNA Level of Circadian Genes and BDNF as Risk Factors of Post-Stroke Cognitive Impairment Among Eastern Indians

Post-stroke cognitive impairment (PSCI) is a clinical outcome in around 30% of post-stroke survivors. BDNF is a major gene in this regard. It is regulated by circadian rhythm. The circadian genes are correlated with stroke timings at molecular level. However, studies suggesting the role of these on susceptibility to PSCI are limited. We aim here to determine: (a) genetic risk variants in circadian clock genes, BDNF and (b) dysregulation in expression level of CLOCK, BMAL1, and BDNF that may be associated with PSCI. BDNF (rs6265G/A, rs56164415C/T), CLOCK (rs1801260T/C, rs4580704G/C), and CRY2 (rs2292912C/G) genes variants were genotyped among 119 post-stroke survivors and 292 controls from Eastern part of India. In addition, we analyzed their gene expression in Peripheral blood Mononuclear cells (PBMC) from 15 PSCI cases and 12 controls. The mRNA data for BDNF was further validated by its plasma level through ELISA (n = 38). Among the studied variants, only rs4580704/CLOCK showed an overall association with PSCI (P = 0.001) and lower Bengali Mini-Mental State Examination (BMSE) score. Its 'C' allele showed a correlation with attention deficiency. The language and memory impairments showed association with rs6265/BDNF, while the 'CC' genotype of rs2292912/CRY2 negatively influenced language and executive function. A significant decrease in gene expression for CLOCK and BDNF in PBMC (influenced by specific genotypes) of PSCI patients was observed than controls. Unlike Pro-BDNF, plasma-level mBDNF was also lower in them. Our results suggest the genetic variants in CLOCK, CRY2, and BDNF as risk factors for PSCI among eastern Indians. At the same time, a lowering expression of CLOCK and BDNF genes in PSCI patients than controls describes their transcriptional dysregulation as underlying mechanism for post-stroke cognitive decline.

Regenerative Potential of Injured Spinal Cord in the Light of Epigenetic Regulation and Modulation

A spinal cord injury is a form of physical harm imposed on the spinal cord that causes disability and, in many cases, leads to permanent mammalian paralysis, which causes a disastrous global issue. Because of its non-regenerative aspect, restoring the spinal cord's role remains one of the most daunting tasks. By comparison, the remarkable regenerative ability of some regeneration-competent species, such as some Urodeles (Axolotl), Xenopus, and some teleost fishes, enables maximum functional recovery, even after complete spinal cord transection. During the last two decades of intensive research, significant progress has been made in understanding both regenerative cells' origins and the molecular signaling mechanisms underlying the regeneration and reconstruction of damaged spinal cords in regenerating organisms and mammals, respectively. Epigenetic control has gradually moved into the center stage of this research field, which has been helped by comprehensive work demonstrating that DNA methylation, histone modifications, and microRNAs are important for the regeneration of the spinal cord. In this review, we concentrate primarily on providing a comparison of the epigenetic mechanisms in spinal cord injuries between non-regenerating and regenerating species. In addition, we further discuss the epigenetic mediators that underlie the development of a regeneration-permissive environment following injury in regeneration-competent animals and how such mediators may be implicated in optimizing treatment outcomes for spinal cord injurie in higher-order mammals. Finally, we briefly discuss the role of extracellular vesicles (EVs) in the context of spinal cord injury and their potential as targets for therapeutic intervention.

Celsr family genes are dynamically expressed in embryonic and juvenile zebrafish

The Cadherin EGF LAG seven-pass G-type receptor (Celsr) family belongs to the adhesion G-protein coupled receptor superfamily. In most vertebrates, the Celsr family has three members (CELSR1-3), whereas zebrafish display four paralogues (celsr1a, 1b, 2, 3). Although studies have shown the importance of the Celsr family in planar cell polarity, axonal guidance, and dendritic growth, the molecular mechanisms of the Celsr family regulating these cellular processes in vertebrates remain elusive. Zebrafish is an experimentally more amenable model to study vertebrate development, as zebrafish embryos develop externally, optically transparent, remain alive with malformed organs, and zebrafish is genetically similar to humans. Understanding the detailed expression pattern is the first step of exploring the functional mechanisms of the genes involved in development. Thus, we report the spatiotemporal expression pattern of Celsr family members in zebrafish nervous tissues. Our analysis shows that celsr1b and celsr2 are expressed maternally. In embryos, celsr1a, celsr1b, and celsr2 are expressed in the neural progenitors, and celsr3 is expressed in all five primary neural clusters of the brain and mantle layer of the spinal cord. In juvenile zebrafish, celsr1a, celsr1b, and celsr2 are presumably expressed in the neural progenitor enriched regions of the CNS. Therefore, the expression pattern of zebrafish Celsr family members is reminiscent of patterns described in other vertebrates or mammalian speciate. This indicates the conserved role of Celsr family genes in nervous system development and suggests zebrafish as an excellent model to explore the cellular and molecular mechanisms of Celsr family genes in vertebrate neurogenesis. This article is protected by copyright. All rights reserved.

Decoding the proregenerative competence of regulatory T cells through complex tissue regeneration in zebrafish

Regulatory T cells (T_regs ) are specific subtype of T cells that play a central role in sustaining self-antigen tolerance and restricting inflammatory tissue damage. More recently, additional direct functions of T_regs in mammalian tissue repair have emerged, but the regenerative potential of T_regs in non-mammalian vertebrates has not been explored despite the latter possessing a highly developed adaptive immune system. Why complex organs such as the caudal fin, heart, brain, spinal cord and retina regenerate in certain non-mammalian vertebrates, but not in mammals, is an interesting but unresolved question in the field of regenerative biology. Inflammation has traditionally been thought to be an impediment to regeneration due to the formation of scars. Regenerative decline in higher organisms has been speculated to be the evolutionary advent of adaptive immunity. Recent studies, however, have shown that the innate inflammatory response in non-mammalian organisms is required for organ regeneration. It has also been found that highly advanced adaptive immunity is no longer incompatible with regeneration and for that, T_regs are important. Zebrafish regulatory T cells (zT_regs ) migrate rapidly to the injury site in damaged organs, where they facilitate the proliferation of regeneration precursor cells by generating tissue-specific regenerative factors by a process distinct from the canonical anti-inflammatory pathway. We review both reparative and proregenerative roles of T_regs in mammals and zebrafish, respectively, and also give an overview of the forkhead box protein 3 (FoxP3) -dependent immunosuppressive function of T_regs in zebrafish, which makes it a useful model organism for future T_reg biology and research.

An insight on established retinal injury mechanisms and prevalent retinal stem cell activation pathways in vertebrate models

Implementing different tools and injury mechanisms in multiple animal models of retina regeneration, researchers have discovered the existence of retinal stem/progenitor cells. Although they appear to be distributed uniformly across the vertebrate lineage, the reparative potential of the retina is mainly restricted to lower vertebrates. Regenerative repair post-injury requires the creation of a proliferative niche, vital for proper stem cell activation, propagation, and lineage differentiation. This seems to be lacking in mammals. Hence, in this review, we first discuss the many forms of retinal injuries that have been generated using animal models. Next, we discuss how they are utilized to stimulate regeneration and mimic eye disease pathologies. The key to driving stem cell activation in mammals relies on the information we can gather from these models. Lastly, we present a brief update about the genes, growth factors, and signaling pathways that have been brought to light using these models.

The loss of regeneration competency in the animal kingdom at the expense of immunity: A journey in retrospect

Regeneration refers to the structural growth of damaged organs or tissues and their functional integration into the existing system. Injury induced regenerative response is extremely variable across the animal kingdom. On one hand the early acoelomates can reform the entire animal even from dissociated cells, on the other; the capacity in humans is mostly restricted to wound healing. A general trend of regenerative ability is the existence of an inverse relationship between the robustness of immune system and the degree of regeneration throughout the animal kingdom. This review summarizes the evolutionary advancement of immune system in different groups and gives an account of their respective regenerative competency.

Neural cells and their progenitors in regenerating zebrafish spinal cord

The zebrafish (Danio rerio), among all amniotes is emerging as a powerful model to study vertebrate organogenesis and regeneration. In contrast to mammals, the adult zebrafish is capable of regenerating damaged axonal tracts; it can replace neurons and glia lost after spinal cord injury (SCI) and functionally recover. In the present paper, we report ultrastructural and cell biological analyses of regeneration processes after SCI. We have focused on event specific analyses of spinal cord regeneration involving different neuronal and glial cell progenitors, such as radial glia, oligodendrocyte progenitors (OPC), and Schwann cells. While comparing the different events, we frequently refer to previous ultrastructural analyses of central nervous system (CNS) injury in higher vertebrates. Our data show (a) the cellular events following injury, such as cell death and proliferation; (b) demyelination and remyelination followed by target innervation and regeneration of synaptic junctions and c) the existence of different progenitors and their roles during regeneration. The present ultrastructural analysis corroborates the cellular basis of regeneration in the zebrafish spinal cord and confirms the presence of both neuronal and different glial progenitors.

Axonal regeneration in zebrafish spinal cord

In the present review we discuss two interrelated events-axonal damage and repair-known to occur after spinal cord injury (SCI) in the zebrafish. Adult zebrafish are capable of regenerating axonal tracts and can restore full functionality after SCI. Unlike fish, axon regeneration in the adult mammalian central nervous system is extremely limited. As a consequence of an injury there is very little repair of disengaged axons and therefore functional deficit persists after SCI in adult mammals. In contrast, peripheral nervous system axons readily regenerate following injury and hence allow functional recovery both in mammals and fish. A better mechanistic understanding of these three scenarios could provide a more comprehensive insight into the success or failure of axonal regeneration after SCI. This review summarizes the present understanding of the cellular and molecular basis of axonal regeneration, in both the peripheral nervous system and the central nervous system, and large scale gene expression analysis is used to focus on different events during regeneration. The discovery and identification of genes involved in zebrafish spinal cord regeneration and subsequent functional experimentation will provide more insight into the endogenous mechanism of myelination and remyelination. Furthermore, precise knowledge of the mechanism underlying the extraordinary axonal regeneration process in zebrafish will also allow us to unravel the potential therapeutic strategies to be implemented for enhancing regrowth and remyelination of axons in mammals.

Combined Phacoemulsification and Nonpenetrating Deep Sclerectomy in the Treatment of Chronic Angle-Closure Glaucoma with Cataract

Purpose

To review the result of nonpenetrating deep sclerectomy (NPDS) combined with phacoemulsification in the treatment of chronic angle-closure glaucoma (CACG) with coexisting cataract.

Methods

This is a retrospective review of 29 eyes of 26 patients who had undergone combined non-penetrating deep sclerectomy and phacoemulsification for cataract and chronic angle-closure glaucoma between January 2001 and June 2003. The visual acuity, intraocular pressure (IOP) and complications were analyzed.

Results

The mean follow-up period was 33.8 months (range 23.3 to 54.0 months). Postoperative visual acuity improved in 21 eyes (72%) and remained the same in 6 eyes (21%). The IOP was reduced significantly from 20.3±3.9 mmHg (mean ± SD) preoperatively to 15.9±3.1 mmHg postoperatively at last follow-up visit (p<0.001). The number of antiglaucoma medications was also reduced significantly from 2.9±0.8 (mean ± SD) preoperatively to 1.0±1.2 at last follow-up (p<0.001). Fifteen eyes (52%) achieved complete success with IOP ≤ 21 mmHg without antiglaucoma medications and 25 eyes (86%) achieved qualified success with IOP ≤ 21 mmHg with or without medications at the last follow-up visit. Of the 25 eyes achieving qualified success, 24 (96%) had a reduction in the number of medications. There were 4 failures, defined as uncontrolled IOP requiring further filtering operation or oral drug treatment. Intraoperative complications included one accidental anterior chamber puncture and one iris plug intraoperatively. Postoperative complications included one choroidal effusion, three wound leaks requiring repair, and two punctate epithelial erosions. There was no shallowing of the anterior chamber, hyphema, hypotony, or infection encountered.

Conclusions

Combined NPDS and phacoemulsification could be a safe and effective surgical option for the management of CACG with cataract. (Eur J Ophthalmol 2007; 17: 208–15)

Regeneration of Zebrafish CNS: Adult Neurogenesis

Regeneration in the animal kingdom is one of the most fascinating problems that have allowed scientists to address many issues of fundamental importance in basic biology. However, we came to know that the regenerative capability may vary across different species. Among vertebrates, fish and amphibians are capable of regenerating a variety of complex organs through epimorphosis. Zebrafish is an excellent animal model, which can repair several organs like damaged retina, severed spinal cord, injured brain and heart, and amputated fins. The focus of the present paper is on spinal cord regeneration in adult zebrafish. We intend to discuss our current understanding of the cellular and molecular mechanism(s) that allows formation of proliferating progenitors and controls neurogenesis, which involve changes in epigenetic and transcription programs. Unlike mammals, zebrafish retains radial glia, a nonneuronal cell type in their adult central nervous system. Injury induced proliferation involves radial glia which proliferate, transcribe embryonic genes, and can give rise to new neurons. Recent technological development of exquisite molecular tools in zebrafish, such as cell ablation, lineage analysis, and novel and substantial microarray, together with advancement in stem cell biology, allowed us to investigate how progenitor cells contribute to the generation of appropriate structures and various underlying mechanisms like reprogramming.

Characterization of Proliferating Neural Progenitors after Spinal Cord Injury in Adult Zebrafish

Zebrafish can repair their injured brain and spinal cord after injury unlike adult mammalian central nervous system. Any injury to zebrafish spinal cord would lead to increased proliferation and neurogenesis. There are presences of proliferating progenitors from which both neuronal and glial loss can be reversed by appropriately generating new neurons and glia. We have demonstrated the presence of multiple progenitors, which are different types of proliferating populations like Sox2⁺ neural progenitor, A2B5⁺ astrocyte/ glial progenitor, NG2⁺ oligodendrocyte progenitor, radial glia and Schwann cell like progenitor. We analyzed the expression levels of two common markers of dedifferentiation like msx-b and vimentin during regeneration along with some of the pluripotency associated factors to explore the possible role of these two processes. Among the several key factors related to pluripotency, pou5f1 and sox2 are upregulated during regeneration and associated with activation of neural progenitor cells. Uncovering the molecular mechanism for endogenous regeneration of adult zebrafish spinal cord would give us more clues on important targets for future therapeutic approach in mammalian spinal cord repair and regeneration.

Genome wide expression profiling during spinal cord regeneration identifies comprehensive cellular responses in zebrafish

BACKGROUND

Among the vertebrates, teleost and urodele amphibians are capable of regenerating their central nervous system. We have used zebrafish as a model to study spinal cord injury and regeneration. Relatively little is known about the molecular mechanisms underlying spinal cord regeneration and information based on high density oligonucleotide microarray was not available. We have used a high density microarray to profile the temporal transcriptome dynamics during the entire phenomenon.

RESULTS

A total of 3842 genes expressed differentially with significant fold changes during spinal cord regeneration. Cluster analysis revealed event specific dynamic expression of genes related to inflammation, cell death, cell migration, cell proliferation, neurogenesis, neural patterning and axonal regrowth. Spatio-temporal analysis of stat3 expression suggested its possible function in controlling inflammation and cell proliferation. Genes involved in neurogenesis and their dorso-ventral patterning (sox2 and dbx2) are differentially expressed. Injury induced cell proliferation is controlled by many cell cycle regulators and some are commonly expressed in regenerating fin, heart and retina. Expression pattern of certain pathway genes are identified for the first time during regeneration of spinal cord. Several genes involved in PNS regeneration in mammals like stat3, socs3, atf3, mmp9 and sox11 are upregulated in zebrafish SCI thus creating PNS like environment after injury.

CONCLUSION

Our study provides a comprehensive genetic blue print of diverse cellular response(s) during regeneration of zebrafish spinal cord. The data highlights the importance of different event specific gene expression that could be better understood and manipulated further to induce successful regeneration in mammals.

Hematologic and genetic characterization of an MYH9-related disorder in a Chinese family

We describe a Chinese family with an MYH9-related disorder in which a novel mutation V1516L at exon 31 of the MYH9 gene was identified. To the best of our knowledge, this is the first reported Chinese family with MYH9 mutation and supports the pan-ethnic nature of the disorder.

New method of surgical repair for 360-degree cyclodialysis

A 44-year-old man suffered traumatic 360-degree cyclodialysis in the left eye complicated by persistent hypotony, disc edema, maculopathy, and cataract. Treatment was removal of the cataract with phacoemulsification followed by insertion of a capsular tension ring with 2-point scleral suture fixation with polypropylene in the ciliary sulcus. A foldable acrylic posterior chamber intraocular lens was implanted in the capsular bag through the 4.1 mm corneal tunnel incision. The intraocular pressure responded well with resolution of hypotony, choroidal detachment, disc edema, and maculopathy. Ultrasound biomicroscopy showed complete closure of the cyclodialysis cleft.

Relationship of Gender, Body Mass Index, and Axial Length with Central Retinal Thickness Using Optical Coherence Tomography

BACKGROUND

Optical coherence tomography (OCT) acquires cross-sectional retinal images with high resolution using low-coherence interferometry. Few studies have studied the effect of demographic data and ocular parameters that may affect central retinal thickness. In this study, these factors were used as parameters to analyse if any significant relationship exists with central retinal thickness.

METHODS

Volunteers with a best-corrected visual acuity of 6/12 or better and no evidence of ocular abnormalities or interventions were recruited from October 2001 to March 2003. Body mass index (BMI), autorefraction, and keratometry recordings were measured, followed by applanation tonometry and A-scan ultrasonography. The central retinal thickness of the right eye was analysed using a scan length of 3 cm. Another 25 eyes were selected for interobserver reproducibility.

RESULTS

In all, 117 normal subjects (60 male and 57 female subjects) were recruited. The mean thickness of the central retina with a diameter of 1 mm was 203+/-23 microm for male and 189+/-20 microm for female subjects. Age, intraocular pressure, and keratometric readings were not significantly correlated with central retinal thickness. Using multiple regression, gender, BMI, axial length, and signal-to-noise ratio (P<0.05) were significantly associated with the central retinal thickness. The intraclass correlation coefficient was 0.98 for interobserver reproducibility.

CONCLUSION

OCT has a high interobserver reproducibility. The male gender, larger BMI, and longer axial length are associated with a significantly thicker central retina and these parameters should be considered for assessing retinal thickening and baseline comparisons in future studies.

Metabolic changes in human CD36 deficiency displayed by glucose loading

Previous in vitro studies have shown that CD36 participates in cellular fatty acid (FA) uptake. In vivo evidence for a physiologic role of CD36 in this process is poor and mostly obtained in animals. To examine the metabolic role of human CD36, we performed a glucose loading test for normals (n = 16) and subjects with CD36 deficiency, both Type I (n = 5) and Type II (n = 16). After 30 min, FA levels had fallen by 60.1% in normals but by only 31.7% in Type II deficiency (P <0.01 vs. normals) and 16.5% in Type I deficiency which remained significantly higher than the other two groups out to 2 h. Further, changes in triglyceride and glucose metabolism were observed in the both types of CD36 deficiency. Impaired fast FA clearance by muscle and consequently increased hepatic FA uptake seem to underlie these changes. We conclude that human CD36 deficiency causes systemic metabolic changes.

Phenotype-genotype correlation in CD36 deficiency types I and II

CD36 deficiency was studied with attention to the phenotype-genotype relationship. The diagnosis of CD36 deficiency was made when CD36 was negative on platelets (type II) or on both platelets and monocytes (type I). Among 827 apparently healthy Japanese volunteers, the type I and II deficiencies were found in 8 (1.0%) and 48 (5.8%), respectively. The T for C substitution at nt478 for Pro90Ser and the insertion of A at nt 1159 constituted the major causes of type I and II deficiencies. The dinucleotide deletion at nt539 had a minor role. In two family studies, we found a previously unreported polymorphic site in the 5'-proximal flanking region and the 3'-untranslated region. Including these new polymorphisms, DNA sequence other than the three known mutations affecting CD36 expression was not observed in the CD36 gene, calling into question the previous hypothesis that a platelet-specific silent allele exists near or at the CD36 gene.

Human CD36 deficiency is associated with elevation in low-density lipoprotein-cholesterol

To find out whether CD36 plays a role in the human lipoprotein metabolism, we studied lipoprotein profiles in subjects with CD36 deficiency. Apparently healthy Japanese volunteers (n = 790) were classified by flow cytometry into three groups of normal (platelet and monocyte CD36+, n = 741, 93.8%), type-II deficiency (platelet CD36- and monocyte CD36+, n = 45, 5.7%), and type-I deficiency (platelet and monocyte CD36-, n = 4, 0.5%). At least one of reported mutations in the CD36 gene was found in all four subjects with type-I deficiency and in 23 of the 45 subjects with type II. Among 779 subjects (731 normals, 44 type II, and four type I) with serum triglyceride levels of <400 mg/dL, serum total cholesterol and low-density lipoprotein (LDL) cholesterol were significantly elevated in type-II deficiency (P = 0.0095 and 0.0382 versus normal, respectively, Scheffe's F-test), while differences were not significant in triglyceride and high-density lipoprotein-cholesterol. Similar tendency was observed in type-I deficiency, although the differences were not statistically significant because of small sample size. We conclude that CD36 deficiency elevates LDL cholesterol, indicating a contribution of CD36 to LDL metabolism.

Conjunctival melanotic lesions in Chinese: comparison with Caucasian series

Conjunctival melanotic lesions in Chinese were studied and compared with those of Caucasians. These lesions were diagnosed in Chinese patients over a two-year period. They were excised under the clinical diagnoses of nevi, primary acquired melanosis (PAM) and malignant melanoma. For the cases included, the histology slides and clinical information were reviewed. Eighteen cases of nevi and nine non-nevoid lesions were identified. Among the non-nevoid lesions, there were eight cases of basal cell hyperpigmentation (one congenital, five acquired, two unknown) and one malignant melanoma. Benign or atypical melanocytic hyperplasias (MH) were not seen. This pattern is very different from that of Caucasian series. Acquired hyperpigmentation is almost only seen in Chinese and seldom in Caucasians. On the other hand, atypical MH is only seen in Caucasians, and not in Chinese. We conclude that conjunctival hyperpigmentation is associated with ethnicity and does not progress to MH, whether benign or atypical. It should be recognised as a distinct entity of no malignant potential that is part of the PAM clinical spectrum.

Dual-function detector-modulator smart-pixel module

We describe a smart-pixel circuit that permits the use of a GaAs/AlGaAs multiple quantum well diode to be used both as a detector for data input and a modulator for data output. The module provides the ability to double the number of inputs or outputs to the array and is well suited to cascaded optoelectronic system architectures that require bidirectional communition.

Quantitative and compositional changes in high density lipoprotein subclasses in patients with various genotypes of cholesteryl ester transfer protein deficiency

High density lipoprotein (HDL) with and without apolipoprotein (apo) E was quantified and characterized in subjects with three genotypes of cholesteryl ester transfer protein (CETP) deficiency: the nonsense mutation in intron 14 (10 homozygotes and 5 heterozygotes); the missense mutation in the exon 15 (3 homozygotes and 9 heterozygotes); and the Int14A/D442G in 6 compound heterozygotes. ApoE-poor and apoE-rich HDL-cholesterol levels were elevated significantly in all genotypic groups with the decrease in CETP activity, indicating that both types of HDL-cholesterol can be a substrate for CETP. However, an unchanged or only slightly increased serum apoA-II level in each genotype indicated that the HDL particles with apoA-II are relatively resistant to CETP-mediated lipid transfer. Serum apoE-rich HDL level was considerably higher in the Int14A homozygotes than in the compound heterozygotes, in spite of similar apoE-poor HDL-cholesterol levels, which may indicate that apoE-rich HDL is a better substrate for CETP than apoE-poor HDL. Although the apoE-rich and apoE-poor HDL subclasses were similar in the accumulation of cholesteryl ester and depletion of triglyceride, the accumulation of free cholesterol was unique to apoE-rich HDL, indicating inhibited cholesterol esterification on this lipoprotein. Clinical laboratories should be aware of the discrepancy in HDL-cholesterol measurements that comes from the different recoveries of apoE-rich HDL using commercial reagents. In conclusion, CETP deficiency causes considerable quantitative and compositional changes in HDL subclasses, reflecting a significant physiological role for CETP in HDL metabolism.

[Frequency and effect on plasma lipoprotein metabolism of a mutation in the cholesteryl ester transfer protein gene in the Chinese]

The aspartate to glycine substitution at codon 442 (D442G) in the cholesteryl ester transfer protein (CETP) gene is a common mutation in Japan and is thought to be a factor that elevates the serum high-density lipoprotein (HDL)-cholesterol level in the general Japanese population. In the present study, we investigated the frequency of the D442G mutation in the Chinese subjects living in Beijing. We also studied the effects of the mutation on plasma lipoprotein metabolism in the same population and compared it with that in the Japanese Diagnosis of D442G mutation was established by polymerase chain reaction followed by restriction digestion. Among 379 subjects studied, 16 were found heterozygous thereto (allelic frequency = 2.1%). Unexpectedly, the D442G mutation was not associated with elevated HDL-cholesterol levels in the Chinese. Instead, in comparison to the unaffected, significantly decreased low-density lipoprotein (LDL)-cholesterol and total cholesterol levels were observed in the heterozygotes. These results were discrepant from those obtained in Japan: Japanese D442G heterozygotes had elevated HDL-cholesterol levels with unchanged LDL-cholesterol and total cholesterol levels. The divergence in the effect of D442G mutation on plasma lipoprotein metabolism appears to be related to the significantly low CETP activities in the Chinese affected and unaffected. Although the difference between Japan and China in nutritional conditions is supposed to contribute to the divergence, the precise mechanism remains to be determined.

Effects of triamcinolone on brain and cerebrospinal fluid apolipoprotein E levels in rats

The effects of the short term administration of triamcinolone (0.5 mg per 100 g body weight, 5 days) on apolipoprotein E and A-I concentrations in cerebrospinal fluid (CSF), brain extract and serum were studied in male Wistar rats using enzyme immunoassays. ApoE was significantly increased by triamcinolone in apoE-rich HDL1 in serum; 40+/-13 (mean+/-SD) vs. 68+/-23 mg/dl (15 saline-treated rats vs. 11 triamcinolone-treated rats)(P<0.01), which was paralleled by an increase in serum apoA-I (76+/-21 vs. 184+/-24 mg/dl), while serum lipids also increased significantly. No significant difference was observed in the apoE concentrations in CSF (296+/-170 vs. 269+/-67 microg/dl) or brain extract (5.0+/-1.6 vs. 5.7+/-1.8 microg/g wet weight). The apoA-I concentrations found in CSF and brain extract were much lower than those for apoE and were not appreciably affected by triamcinolone: 7.7+/-5.5 vs. 4.5+/-3.1 microg/dl for CSF and <0.5 vs. <0.5 microg/g wet weight for brain extract. The apo E metabolism in the rat central nervous system appears to be refractory to the short term administration of triamcinolone and to changes in the serum lipoprotein metabolism. ApoA-I appears unlikely to play a significant role in the rat central nervous system.

Photonic page buffer based on GaAs multiple-quantum-well modulators bonded directly over active silicon complementary-metal-oxide-semiconductor (CMOS) circuits: errata

Owing to printing errors, [Appl. Opt. 35, 2439 (1996)] several figures were illegible. The figures are reprinted and briefly reviewed.

Native lipoproteins inhibit platelet activation induced by oxidized lipoproteins

Copper-catalyzed oxidation of low-density lipoproteins (LDL) (0.8 g protein/l LDL, 20 mumol/l CuSo4, 37 degrees C) resulted in the formation of thiobarbituric reactive substances that was substantially completed at 24 hrs whereas their formation from high-density lipoproteins (HDL) plateaued at only 25% of that amount after 8 hrs. The oxidized lipoproteins induced aggregation and increases in [Ca2+]i in washed platelets, but not in platelet-rich plasma, and these activating effects were not inhibited by aspirin or EGTA but were inhibited by both of the native lipoproteins. These results show that oxidized HDL, like oxidized LDL, have platelet activating ability and suggest that the native lipoproteins may play a crucial role in preventing the oxidized lipoprotein-mediated platelet activation.

Photonic page buffer based on GaAs multiple-quantum-well modulators bonded directly over active silicon complementary-metal-oxide-semiconductor (CMOS) circuits

We present a 2-kbit, 50-Mpage/s, photonic first-in, first-out page buffer based on gallium arsenide/aluminium-gallium arsenide multiple-quantum-well diodes that are flip-chip bonded to submicrometer silicon complementary-metal-oxide-semiconductor circuits. This photonic chip provides nonvolatile storage (buffering), asynchronous-to-synchronous conversion, bandwidth smoothing, tolerance to jitter or skew, spatial format conversion, wavelength conversion, and independent flow control for the input and the output channels. It serves as an interface chip for parallel-accessed optical bit-plane data. It represents the first smart-pixel array that accomplishes the vertical integration of multiple-quantum-well modulators and detectors directly over active silicon VLSI circuits and provides over 340 transistors per optical input-output. Results from high-speed single-channel testing and real-time array operation of the photonic page buffer are reported.

Evaluation of G-to-A substitution in the apolipoprotein A-I gene promoter as a determinant of high-density lipoprotein cholesterol level in subjects with and without cholesteryl ester transfer protein deficiency

The effect of a polymorphism, guanine (G) to adenine (A) substitution in the promoter of apolipoprotein A-I gene at a position 78 bp upstream of the transcription initiation site, on the serum high-density lipoprotein (HDL)-cholesterol level was studied in 168 Japanese subjects with HDL-cholesterol levels ranging from 26 to 171 mg/dl. Considering the significant effect of cholesteryl ester transfer protein (CETP) on the HDL-cholesterol level and the common occurrence of its deficiency, we performed statistical analyses separately for two groups: one without CETP deficiency (n = 126) and the other with CETP deficiency (n = 42). In the group without CETP deficiency, in which the numbers of G/G, G/A, and A/A genotypes were 92 (73.0%), 28 (22.2%), and 6 (4.8%), respectively, the frequency of the A allele in the subjects with HDL-cholesterol levels of > or = 70 mg/dl did not differ from subjects with HDL-cholesterol levels of < or = 69 mg/dl, irrespective of gender: 0.154 and 0.145 in males, and 0.182 and 0.174 in females, respectively, for the > or = 70 mg/dl and < or = 69 mg/dl groups. Additionally, the HDL-cholesterol levels for the subjects with the G/G genotype did not differ from those for the subjects with the A allele: 64 +/- 22, 58 +/- 14, 77 +/- 14 and 62 +/- 16 mg/dl, respectively, for the G/G, G/A, A/A, and G/A + A/A in males, and 72 +/- 18, 74 +/- 24, 63 +/- 4, and 73 +/- 23 mg/dl in females. For the group with CETP deficiency, in which the numbers of G/G and G/A + A/A genotypes were 25 (59.5%) and 17 (40.5%), the HDL-cholesterol levels also did not differ: 98 +/- 24 mg/dl and 99 +/- 30 mg/dl, respectively, for the G/G and G/A + A/A genotypes. Thus, there is no evidence that the polymorphism has any effect on serum HDL-cholesterol levels regardless of CETP status. We conclude that the G-to-A substitution in the promoter of apolipoprotein A-I gene does not significantly alter serum HDL-cholesterol level.

Nitrogen control of Salmonella typhimurium: co-regulation of synthesis of glutamine synthetase and amino acid transport systems

Nitrogen control in Salmonella typhimurium is not limited to glutamine synthetase but affects, in addition, transport systems for histidine, glutamine, lysine-arginine-ornithine, and glutamate-aspartate. Synthesis of both glutamine synthetase and transport proteins is elevated by limitation of nitrogen in the growth medium or as a result of nitrogen (N)-regulatory mutations. Increases in the amounts of these proteins were demonstrated by direct measurements of their activities, by immunological techniques, and by visual inspection of cell fractions after gel electrophoresis. The N-regulatory mutations are closely linked on the chromosome to the structural gene for glutamine synthetase, glnA: we discuss the possibility that they lie in a regulatory gene, glnR, which is distinct from glnA. Increases in amino acid transport in N-regulatory mutant strains were indicated by increased activity in direct transport assays, improved growth on substrates of the transport systems, and increased sensitivity to inhibitory analogs that are trnasported by these systems. Mutations to loss of function of individual transport components (hisJ, hisP, glnH, argT) were introduced into N-regulatory mutant strains to determine the roles of these components in the phenotype and transport behavior of the strains. The structural gene for the periplasmic glutamine-binding protein, glnH, was identified, as was a gene argT that probably encodes the structure of the lysine-arginine-ornithine-binding protein. Genes encoding the structures of the histidine- and glutamine-binding proteins are not linked to glnA or to each other by P22-mediated transduction; thus, nitrogen control is exerted on several unlinked genes.