CHOLESTEROL AND DEVELOPMENT: THE RSH ("SMITH-LEMLI-OPITZ") SYNDROME AND RELATED CONDITIONS

The half-century of lipophobia in the United States may be abating with some return of sanity on the discussion of health and dietary fat [Taubes, 2001]. The youngest victims of this collective, decades long madness are those infants deprived for one reason or another of breast milk. They are unable to speak for themselves at a time of greatest need for cholesterol during growth, the most critical period of myelination of central and peripheral nervous system, formation of bone and bile, and of every steroid hormone. Some of the commercial formulas they are fed contain only 1 or 2 mg of cholesterol per 100 g edible portion contrasted with almost 14 mg in breast milk. One can only hope that the confidence in their endogenous ability to synthesize sufficient amounts of cholesterol is not misplaced. Pediatric pathology has learned that when this endogenous ability fails during embryogenesis on the basis of mutations in the postsqualene biosynthesis of cholesterol, a startling variety of developmental pathology may present itself ranging from lethal forms of "idiopathic" hydrops, microcephaly with cerebral dysgenesis and dysmyelinization, agenesis of corpus callosum, cerebellar vermis dysgenesis, cataracts, cleft palate, many different forms of congenital heart defect, pyloric stenosis and/or Hirschsprung dysganglionosis, adrenal (cortical) insufficiency, cholestatic liver disease, limb malformations, and genital ambiguity in genetic males. Population genetic considerations suggest a hypothetical birth prevalence of the RSH (so-called Smith-Lemli-Opitz) syndrome, the commonest of these Garrodian errors of cholesterol biosynthesis, of 1/2500; since only about 1/15,000 to 1/20,000 homozygotes are liveborn and biochemically confirmed, over 80% prenatal or perinatal mortality must occur and deserves the most discerning of services from birth attendants, perinatologists, neonatologists, and fetal/pediatric pathologists. An easy, reliable, economical biochemical test for the presence of 7-dehydrocholesterol is available and the commonest mutation, the IVS8-1G →C mutation, is quickly and reliably tested for molecularly. Thus, the successful diagnosis, even after death, will contribute substantially to correct genetic counseling, carrier detection, prenatal diagnosis, and treatment in those known to be affected prenatally and planned to be liveborn. Thus, developmental pathology plays an integral, vital role in preventive medicine.     

Shh信号通路成员Shh蛋白在胃癌细胞SGC-7901中的表达

目的：研究Shh信号通路成员Shh蛋白在胃癌细胞中的表达，探讨其与胃癌发生的关系。方法：培养胃癌细胞（SGC-7901）和正常肠上皮细胞（IEC-6），用免疫细胞化学法检测两种细胞中Shh蛋白的表达，用RT—PCR法检测Shh mRNA在两种细胞中的表达。结果：Shh蛋白在正常肠上皮细胞中表达阳性率为15％，在胃癌细胞中表达阳性率为70％，Shh蛋白在正常肠上皮细胞中的表达明显低于胃癌细胞（P〈0．05）。Shh mRNA在正常肠上皮细胞中不表达或低表达，在胃癌细胞中明显表达（P〈0.05）。结论：Shh信号通路可能与胃癌发生有关。     

儿童肾母细胞瘤Hedgehog通路相关分子BMI1和Gli1 表达及意义

目的探讨Hedgehog信号通路相关分子BMI1和Gli1在儿童肾母细胞瘤(NB)组织中的表达情况及其与预后的关系。方法收集37例NB患儿的NB组织及其癌旁正常组织的病理标本,通过免疫组织化学染色法观察BMI 1和Gli 1蛋白在肿瘤组织中的表达,分析其与NB患儿临床病理特征以及血清肿瘤标志物的关系。利用公共数据库分析BMI 1和Gli1 mRNA表达与NB患儿预后的关系。结果 37例患儿中男14例、女23例,中位年龄2岁(3个月～6岁)。NB组织中BMI 1和Gli 1蛋白表达均较癌旁正常组织增高,差异有统计学意义(P0. 01)。BMI 1阳性细胞在37例患儿肿瘤组织均被观察到,而Gli1阳性细胞在16例患儿肿瘤组织中未检测到。22例BMI1高表达的NB患儿更容易出现远隔转移,血清甲胎蛋白、糖类抗原-125(CA-125)表达增高,同时总体生存期也更短,差异均有统计学意义(P0.05);Gli1表达增高则与NB患儿临床病理特征或预后无相关性。结论 Hedgehog通路相关分子BMI 1和Gli 1在NB肿瘤组织中表达增高,BMI 1与肿瘤转移和预后不良呈正相关,可能是NB发展的一个重要影响因素。     

C-mode real-time tomographic reflection for a matrix array ultrasound sonic flashlight

RATIONALE AND OBJECTIVES: Real-time tomographic reflection (RTTR) permits in situ visualization of tomographic images so that natural hand-eye coordination can be used directly during invasive procedures. The method uses a half-silvered mirror to merge the visual outer surface of the patient with a simultaneous scan of the patient's interior without requiring a head-mounted display or tracking. A viewpoint-independent virtual image is reflected precisely into its actual location. When applied to ultrasound, we call the resulting RTTR device the sonic flashlight. We previously implemented the sonic flashlight using conventional two-dimensional ultrasound scanners that produce B-mode slices. Real-time three-dimensional (RT3D) ultrasound scanners recently have been developed that permit RTTR to be applied to slices with other orientations, including C-mode (parallel to the face of the transducer). Such slice orientation may offer advantages for image-guided intervention. MATERIALS AND METHODS: Using a prototype scanner developed at Duke University (Durham, NC) with a matrix array that electronically steers an ultrasound beam at high speed in 3D, we implemented a sonic flashlight capable of displaying C-mode images in situ in real time. RESULTS: We present the first images from the C-mode sonic flashlight, showing bones in the hand and the cardiac ventricles. CONCLUSION: The extension of RTTR to matrix array RT3D ultrasound offers the ability to visualize in situ slices other than the conventional B-mode slice, including C-mode slices parallel to the face of the transducer. This orientation may provide a broader target, facilitating certain interventional procedures. Future work is discussed, including display of slices with arbitrary orientation and use of a holographic optical element instead of a mirror.     

Differential expression of cell fate determinants in neurons and glial cells of adult mouse spinal cord after compression injury

Cellular responses after spinal cord injury include activation of astrocytes, degeneration of neurons and oligodendrocytes, and reactions of the ependymal layer and meningeal cells. Because it has been suggested that tissue repair partially recapitulates morphogenesis, we have investigated the expression of several developmentally prominent molecules after spinal cord injury of adult mice where neurogenesis does not occur after injury. Cell fate determinants Numb, Notch-1, Shh and BMPs are abundantly expressed during development but mostly decline in the adult. In the present study, we investigated whether these genes are triggered by spinal cord injury as a sign of attempted recapitulation of development. Expression of Numb, Notch, Shh, BMP2/4 and Msx1/2 was analysed in the adult mouse spinal cord after compression injury by in situ hybridization up to 1 month after injury. The mRNA expression levels of Notch-1, Numb, Shh, BMP4 and Msx2 increased in the grey matter and/or white matter and in the ependyma rostral and caudal to the lesion site after injury. However, BMP2 and Msx1 were not up-regulated. Combining immunohistochemistry of cell type-specific markers with in situ hybridization we found that all the up-regulated genes were expressed in neurons. Moreover, Numb, BMP4 and Msx2 were also expressed by GFAP-positive astrocytes, while Shh was expressed by MBP-positive oligodendrocytes. In conclusion, the cell fate determinants Notch-1, Numb, Shh, BMP4 and Msx2 are expressed in neurons and/or glial cells after injury in a time-dependent manner, suggesting that these genes reflect to some extent an endogenous self-repair potential by recapitulating some features of development.     

Sonic hedgehog delivered by an adeno-associated virus protects dopaminergic neurones against 6-OHDA toxicity in the rat

Summary. Direct intracerebral administration of sonic hedgehog (SHH) reduces 6-OHDA and MPTP toxicity to nigral dopaminergic cells in rats and primates. To determine whether transfection of the DNA sequence for SHH using viral vectors also protects against 6-OHDA toxicity, a type 2 adeno- associated virus (AAV) incorporating 600 base pairs of N-terminal SHH DNA was generated to induce SHH expression in rat striatum.AAV-SHH was injected into the striatum, 3 weeks prior to the initiation of an unilateral partial 6-OHDA nigro-striatal lesion. Animals receiving 4×10⁷ viral particles of AAV-SHH showed a reduction in (+)-amphetamine induced ipsilateral turning over 4 weeks, when compared to animals receiving vehicle or a LacZ encoding vector. Following vehicle or AAV-LacZ administration, 6-OHDA caused a marked loss of striatal dopamine content and nigral tyrosine hydroxylase (TH) immunopositive cells. Following treatment with 4×10⁷ viral particles of AAV-SHH the loss of striatal dopamine content was reduced and there was marked preservation of nigral dopaminergic cells. However, administration of 4×10⁸ particles of AAV-SHH did not cause a significant change in (+)-amphetamine-induced rotation, striatal dopamine levels or the number of nigral TH immunoreactive cells following 6-OHDA lesioning compared to vehicle or AAV-LacZ treated animals.The results show that SHH delivered via a viral vector can protect dopaminergic neurons against 6-OHDA toxicity and suggest that this could be developed into a novel treatment for PD. However, the effects maybe dose limited due to uncoupling of hedgehog receptor signalling at higher levels of SHH expression.Present address: Synta Pharmaceuticals Corp., Lexington, MA, USA     

Molecules affecting myelin stability: a novel hypothesis regarding the pathogenesis of multiple sclerosis

In this Mini-Review we present a new hypothesis in support of the neurodegenerative theory as a mechanism for the pathogenesis of multiple sclerosis (MS). The pathogenesis of MS results from changes in two distinct CNS compartments. These are the "myelin" and "nonmyelin" compartments. The myelin compartment is where primary demyelination, amidst attempts at remyelination, is superseded in the CNS by ongoing disease. Recent evidence obtained via magnetic resonance imaging and spectroscopy techniques supports the view that the normal-appearing white matter (NAWM) in the MS brain is altered. Several biochemical changes in NAWM have been determined. These include the cationicity of myelin basic protein (MBP) as a result of the action of peptidyl argininedeiminase (PAD) activity converting arginyl residues to citrulline. The accompanying loss of positive charge makes myelin susceptible to vesiculation and MBP more susceptible to proteolytic activity. An increase of MBP autocatalysis in the MS brain might also contribute to the generation of immunodominant epitopes. Accompanying the destruction of myelin in the myelin compartment is the activation of astrocytes and microglia. These contribute to the inflammatory response and T-cell activation leading to autoimmunity. The complex environment that exists in the demyelinating brain also affects the "nonmyelin" compartment. The inappropriate up-regulation of molecules, including those of the Jagged-1-Notch-1 signal transduction pathway, affects oligodendrocyte precursor cell (OPC) differentiation. Other effectors of oligodendrocyte maturation include stathmin, a microtubule-destabilizing protein, which prevents healing in the demyelinating brain. The hypothesis we present suggests a therapeutic strategy that should 1) target the effectors within the myelin compartment and 2) enable resident OPC maturation in the nonmyelin compartment, allowing for effective repair of myelin loss. The net effect of this new therapeutic strategy is the modification of the disease environment and the stimulation of healing and repair.     

Spectrum of holoprosencephaly

Objective : To conduct a clinical study of holoprosencephaly (HPE).Method : Thirteen cases of HPE were studied regarding their clinical features, family history, and prenatal and imaging studies. Chromosomal analysis was done whenever fresh sample was available.Results : Six cases were antenatally detected by ultrasound; four cases were stillborn. Three cases were identified by neuroimaging done a part of evaluation of developmental delay or cleft lip. Eleven of them had facial anomalies characteristics of HPE. Two of these had subtle facial features and microcephaly. Karyotype was abnormal in 2 of 7 cases studied.Conclusion : Most of the cases of HPE present antenatally or at birth. Milder forms like lobar and semilobar can present as developmental delay during infancy. Facial anomalies are usually associated with HPE. Chromosomal study of the case and clinical examination of the parents is essential for providing information regarding risk of recurrence to the family.     

Sonic hedgehog and Glis famliy expression in the human neonatal of congenital esophageal atresia and tracheoesophageal fistula

目的 研究Sonic hedgehog基因及Gli家族在人类先天性食管闭锁并气管食管瘘(esophageal atresia and tracheoesophageal fistula,EA-TEF)的表达特点,探讨EA-TEF病因及发病机制的可能影响因素.方法 食管吻合术中留取22例EA-TEF患儿近端食管盲端及远端气管食管瘘管组织,7例行HE染色,10例行real-time RT-PCR处理,5例行免疫荧光染色处理.观察食管盲端及气管食管瘘管形态上的变化及各指标的差异.结果 ①形态学:瘘管组织内皮下可见粘液腺体,肌层稀疏且肌肉组织结构紊乱；②Shh表达:食管盲端组织中可见表达,瘘管组织中未有表达；③Glis表达:Gli-1、Gli-3mRNA表达无差异,Gli-2mRNA表达差异有统计学意义(P＜0.05),瘘管中表达低于食管盲袋.结论 气管食管瘘组织具有气管源性特征.EA-TEF的发生可能与Shh信号通路表达下调有关.Gli-2的功能缺失在EA-TEF的发生中可能发挥重要作用.     

Sonic hedgehog signaling during nervous system development*☆

The Hedgehog signaling pathway plays a key role in embryonic development and organ formation. Sonic hedgehog signaling participates in nervous system development, regulates proliferation and differentiation of neural stem cells, controls growth and targeting of axons, and contributes to specialization of oligodendrocytes. For further studies of the Sonic hedgehog signaling pathway and for the development of new drugs in the treatment of nervous system diseases, it is beneficial to understand these mechanisms.