Stereoselective Intramolecular [2+2] Trapping of 1,2-Cyclohexadienes: a Route to Rigid, Angularly Fused Tricyclic Scaffolds.

1,2-Cyclohexadienes generated under mild fluoride-mediated desilylative conditions undergo efficient intramolecular [2+2] trapping, providing tricyclic alkylidene cyclobutanes with complete diastereoselectivity for the cis-fused products. Pendent styrenes or electron-deficient olefins can trap simple 1,2-cyclohexadienes or their oxygenated counterparts, with 14 substrates being disclosed. Reactions proceed at ambient temperature using just cesium fluoride in up to 91 % yield, and the necessary precursors are easily accessed from substituted 2-bromocyclohexenones. Multiple synthetic routes have been developed to install the appropriate functional groups required for [2+2] trapping.

Efficient Trapping of 1,2-Cyclohexadienes with 1,3-Dipoles.

1,2-Cyclohexadienes are transient intermediates that undergo rapid dimerization and intermolecular trapping with activated olefins and heteroatomic nucleophiles. Fluoride-mediated desilylative elimination of readily accessible 6-silylcyclohexene-1-triflates allows the mild, chemoselective, and functional-group tolerant generation of cyclic allene intermediates, which undergo efficient trapping reactions with stable 1,3-dipoles. The reactions proceed with high levels of both regio- and diastereoselectivity. The reaction of cyclic allenes with azides is accompanied by the facile loss of dinitrogen, resulting in the formation of tetrahydroindoles or polycylic aziridines depending on the azide employed.

Formation and Trapping of Azafulvene Intermediates Derived from Manganese-Mediated Oxidative Malonate Coupling.

The one-pot, three-component, coupling reaction of indoles/pyrroles, dimethyl malonate, and acetic acid was performed using Mn(III) acetate as an oxidant. In the presence of Mn(OAc)3, indole-2, and indole-3-carbonyl compounds were alkylated at the 3- and 2- positions, respectively, with subsequent oxidation and nucleophilic capture occurring at the newly formed benzylic carbon. In contrast, oxidation of 2- and 3-indole carboxylic acids afforded the corresponding 2-oxindol-3-ylidenes and 3-oxindol-2-ylidenes. The reaction conditions, scope, and mechanism are discussed herein.

Strain-Activated Diels-Alder Trapping of 1,2-Cyclohexadienes: Intramolecular Capture by Pendent Furans.

Intramolecular [4 + 2] cycloaddition reactions of substituted 1,2-cyclohexadienes with pendent furans enables the synthesis of complex tetracyclic scaffolds in a single step under mild conditions. All Diels-Alder cycloadducts were obtained as single diastereomers, assigned as the endo isomer. Substrates were easily assembled via Stork-Danheiser alkylation of 3-ethoxy-2-bromocyclohex-2-enone to accommodate a range of tethers and furan traps. Cleavage of enol acetate moieties resulted in room-temperature Diels-Alder cycloreversion to tethered furyl cyclohexenones.

Effect of taurine supplementation on growth and development in preterm or low birth weight infants.

BACKGROUND: Taurine is the most abundant free amino acid in breast milk. Evidence exists that taurine has important roles in intestinal fat absorption, hepatic function, and auditory and visual development in preterm or low birth weight infants. Observational data suggest that relative taurine deficiency during the neonatal period is associated with adverse long-term neurodevelopmental outcomes in preterm infants. Current standard practice is to supplement formula milk and parenteral nutrition solutions with taurine. OBJECTIVES: To assess the effect of providing supplemental taurine for enterally or parenterally fed preterm or low birth weight infants on growth and development. SEARCH STRATEGY: The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2007), MEDLINE (1966 - June 2007), EMBASE (1980 - June 2007), conference proceedings, and previous reviews. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials that compared taurine supplementation versus no supplementation in preterm or low birth weight newborn infants. DATA COLLECTION AND ANALYSIS: Data were extracted using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two review authors, and synthesis of data using relative risk, risk difference and weighted mean difference. MAIN RESULTS: Nine small trials were identified. In total, 189 infants participated. Most participants were greater than 30 weeks gestational age at birth and were clinically stable. In eight of the studies, taurine was given enterally with formula milk. Only one small trial assessed parenteral taurine supplementation. Taurine supplementation increased intestinal fat absorption [weighted mean difference 4.0 (95% confidence interval 1.4, 6.6) percent of intake]. However, meta-analyses did not reveal any statistically significant effects on growth parameters assessed during the neonatal period or until three to four months chronological age [rate of weight gain: weighted mean difference -0.25 (95% confidence interval -1.16, 0.66) grams/kilogram/day; change in length: weighted mean difference 0.37 (95% confidence interval -0.23, 0.98) millimetres/week; change in head circumference: weighted mean difference 0.15 (95% confidence interval -0.19, 0.50) millimeters/week]. There are very limited data on the effect on neonatal mortality or morbidities, and no data on long-term growth or neurological outcomes. AUTHORS' CONCLUSIONS: Despite that lack of evidence of benefit from randomised controlled trials, it is likely that taurine will continue to be added to formula milks and parenteral nutrition solutions used for feeding preterm and low birth weight infants given the putative association of taurine deficiency with various adverse outcomes. Further randomised controlled trials of taurine supplementation versus no supplementation in preterm or low birth weight infants are unlikely to be viewed as a research priority, but there may be issues related to dose or duration of supplementation in specific subgroups of infants that merit further research.

Transmission-ratio distortion through F1 females at chromosome 11 loci linked to Om in the mouse DDK syndrome.

We determined the genotypes of > 200 offspring that are survivors of matings between female reciprocal F1 hybrids (between the DDK and C57BL/6J inbred mouse strains) and C57BL/6J males at markers linked to the Ovum mutant (Om) locus on chromosome 11. In contrast to the expectations of our previous genetic model to explain the "DDK syndrome, " the genotypes of these offspring do not reflect preferential survival of individuals that receive C57BL/6J alleles from the F1 females in the region of chromosome 11 to which the Om locus has been mapped. In fact, we observe significant transmission-ratio distortion in favor of DDK alleles in this region. These results are also in contrast to the expectations of Wakasugi's genetic model for the inheritance of Om, in which he proposed equal transmission of DDK and non-DDK alleles from F1 females. We propose that the results of these experiments may be explained by reduced expression of the maternal DDK Om allele or expression of the maternal DDK Om allele in only a portion of the ova of F1 females.

Sex-of-offspring-specific transmission ratio distortion on mouse chromosome X.

During our study of the DDK syndrome, we observed sex ratio distortion in favor of males among the offspring of F(1) backcrosses between the C57BL/6 and DDK strains. We also observed significant and reproducible transmission ratio distortion in favor of the inheritance of DDK alleles at loci on chromosome X among female offspring but not among male offspring in (C57BL/6 x DDK)F(1) x C57BL/6 and (C57BL/6-Pgk1(a) x DDK)F(1) x C57BL/6 backcrosses. The observed transmission ratio distortion is maximum at DXMit210 in the central region of chromosome X and decreases progressively at proximal and distal loci, in a manner consistent with the predictions of a single distorted locus model. DXMit210 is closely linked to two distortion-controlling loci (Dcsx1 and Dcsx2) described previously in interspecific backcrosses. Our analysis suggests that the female-offspring-specific transmission ratio distortion we observe is likely to be the result of the death of embryos of particular genotypic combinations. In addition, we confirm the previous suggestion that the transmission ratio distortion observed on chromosome X in interspecific backcrosses is also the result of loss of embryos.

Localisation of a gene for mucopolysaccharidosis IIIC to the pericentromeric region of chromosome 8.

Mucopolysaccharidosis type IIIC (MPS IIIC, or Sanfilippo syndrome C) is a rare lysosomal storage disorder caused by a deficiency of acetyl-coenzyme A:alpha-glucosaminide-N-acetyltransferase. Patients develop progressive neuropsychiatric problems, mental retardation, hearing loss, and relatively minor visceral manifestations. The pattern of transmission is consistent with an autosomal recessive mode of inheritance. The aim of this study was to find a locus for MPS IIIC using a homozygosity mapping approach. A genomewide scan was performed on DNA from 27 affected individuals and 17 of their unaffected relatives. Additional patients were recruited, and DNA was obtained from a total of 44 affected individuals and 18 unaffected family members from 31 families from 10 countries. A working candidate interval was defined by looking for excess homozygosity in patients compared with their relatives. Additional markers were genotyped in regions of interest. Linkage analysis was performed to support the informal analysis. Inspection of the genomewide scan data showed apparent excess homozygosity in patients compared with their relatives for markers on chromosome 8. Additional genotyping identified 15 consecutive markers (from D8S1051 to D8S2332) in an 8.3 cM interval for which the genotypes of affected siblings were identical in state. A maximum multipoint lod score of 10.61 was found at marker D8S519. A locus for MPS IIIC maps to an 8.3 cM (16 Mbp) interval in the pericentromeric region of chromosome 8.

Genetic mapping of X-linked loci involved in skewing of X chromosome inactivation in the human.

We have analyzed X-chromosome inactivation patterns in lymphocytes of 264 females from 38 families not known to have any genetic disease. Quantitative measures of X-inactivation showed strong sister-sister correlation in the degree of departure from equal numbers of cells having each X chromosome active, suggesting heritability of this phenotype. Strong sister-sister correlation was also observed for the fraction of cells having the same parent's X chromosome active, consistent with the possibility that this trait might be controlled by a cis-acting, X-linked gene. We used a sib-pair approach to determine whether X-inactivation phenotype was linked to loci in any region of the X chromosome. Both quantitative and discrete measures of X-inactivation phenotype showed evidence of linkage to markers in the region of the X inactivation center (XIC). The quantitative measure of X-inactivation phenotype used in our study also showed linkage to loci at Xq25-q26. This study provides the first evidence for X-linked inheritance of X chromosome inactivation phenotype derived from linkage analysis in phenotypically normal human families.

Cellular responses of embryonic hyaline cartilage to experimental wounding in vitro.

It is well established that the reparative potential of many tissues is greatest during embryonic development. Despite the extensive literature documenting repair in nonembryonic cartilage models, there is no comparable wealth of experience relating to embryonic cartilage repair. With the embryonic chick sternum as a model of hyaline cartilage, this paper accounts cellular responses and alterations in extracellular matrix composition in response to experimental wounding in vitro. Creation of an experimental lesion induced a rapid (<20 minutes) apoptotic response in chondrocytes adjacent to the lesion edge; the presence of perichondrium delayed this response. Alterations in the extracellular matrix included immediate mechanical damage to type-II collagen fibrils and an increase in the expression of chondroitin-4 sulphate next to the lesion. Creation of the lesion induced an increased proliferative response in chondrocytes behind the zone of apoptosis and the expression of alpha5 and alpha6 integrin subunits.

[Mitochondrial oxidation and ultrastructure of the myocardium on a background of incorporation of cesium radionuclides]. / Mitokhondrial'noe okislenie i ul'trastruktura miokarda pri inkorporatsii radionuklidov tseziia.

Parameters of the mitochondrial oxidation and ultrastructure of the myocardium in white rats were studied on a background of consumption of food supplemented with 137Cs at 60 or 600 Bq/kg (calculated doses were 1.5 and 15 microGy, respectively). The observed stimulation of the respiratory activity in myocardial samples cultivated on endogenous and several exogenous substrates was found to reduce the effectiveness of energy production by dissociation of oxidative phosphorylation and disruption of macroerg deposition in the form of creatine phosphate. Ultrastructural findings included swelling of mitochondria, matrix clarification, partial reduction of the number of crists, and myeline-like bodies in the matrix. Observed were high nucleus structural polymorphism with extension of the perinuclear space, spotted distribution of chromatin, and modification of the myofibril structure. These morphofunctional changes can be considered as reflection of apoptosis associated with activation of peroxidation.

[Characteristics of mitochondria and myocardium ultrastructure of rats following chronic incorporation of cesium radionuclides 137 Cs]. / Kharakteristika mitokhondrii i ul'trastruktura miokarda krys v usloviiakh prodolzhitel'noi inkorporatsii radionuklidov 137 Cs.

Ultrastructure, tissue respiration and oxidative phosphorilation were studies in the myocardium of animals after chronic natural irradiation by 137Cs in quantities that can in reality threaten population of radionuclide-polluted regions. Decline in the respiratory activity of the myocardium and ultrastructural disorders can be attributed to the effects of ions of radioactive Cs which is also a potassium antagonist. A hypothesis has been put forward according to which cesium blocks potassium channels in mitochondria and thus changes the volume and configuration of internal mitochondrial membranes, and impacts the respiratory processes. In the opinion of the authors, these changes characterize the mitochondrial phase of apoptosis which, in the event of chronic exposure to radionuclides, is a compensatory-adaptive mechanism eliminating the least immutable subpopulation of cardiomyocites.

Extensive cervical spine and foregut anomaly in 'serpentine syndrome'.

INTRODUCTION: We report an extremely rare and challenging combination of congenital anomalies. Only five similar cases have been described in the English language medical literature to date. PRESENTATION OF CASE: A male infant was born at 30(+5) weeks gestation by emergency caesarian section. Cervical spine rachischisis, shortened oesophagus, intrathoracic stomach, atretic duodenum and absent spleen were noted, in addition to respiratory insufficiency. Gastrointestinal re-anastomosis, particularly oesophageal lengthening, was not feasible at the initial thoracotomy. Surgical stabilization of the cervical spine was unlikely to be successful until two years of age. Asplenia predisposed the infant to sepsis from encapsulated organisms, and recurrent respiratory infections occurred. DISCUSSION: A close relationship exists between the upper gastrointestinal tract and cervical spine during embryonic development. An embryonic aberration at this level could account for all the deformities present in this infant. Tethering of the embryonic cervical oesophagus to the somites in the first trimester, preventing foregut elongation, and producing ischaemia at the coeliac axis, is suggested as the aetiology. CONCLUSION: This case presented a challenge to the multi-disciplinary team involved in his management and prompted extensive consultation with international experts. After considerable counseling of the parents, care was directed towards palliation.

Identification of a major susceptibility locus for restless legs syndrome on chromosome 12q.

Restless legs syndrome (RLS) is a neurological disorder characterized by leg paresthesia associated with an irresistible urge to move that often interferes with nocturnal sleep, leading to chronic sleep deprivation. To map genes that may play a role in the vulnerability to RLS, a genomewide scan was conducted in a large French-Canadian family. Significant linkage was established on chromosome 12q, for a series of adjacent microsatellite markers with a maximum two-point LOD score of 3.42 (recombination fraction.05; P=6x10(-4); autosomal recessive mode of inheritance), whereas multipoint linkage calculations yielded a LOD score of 3.59. Haplotype analysis refined the genetic interval, positioning the RLS-predisposing gene in a 14.71-cM region between D12S1044 and D12S78. These findings represent the first mapping of a locus conferring susceptibility to RLS.

Confirmation of maternal transmission ratio distortion at Om and direct evidence that the maternal and paternal "DDK syndrome" genes are linked.

The polar, preimplantation-embryo lethal phenotype known as the "DDK syndrome" in the mouse is the result of the complex interaction of genetic factors and a parental-origin effect. We previously observed a modest degree of transmission-ratio distortion in favor of the inheritance of DDK alleles in the Ovum mutant (Om) region of Chromosome (Chr) 11, among offspring of reciprocal F1-hybrid females and C57BL/6 males. In this study, we confirm that a significant excess of offspring inherit DDK alleles from F1 mothers and demonstrate that the preference for the inheritance of DDK alleles is not a specific bias against the C57BL/6 allele or a simple preference for offspring that are heterozygous at Om. Because none of the previous genetic models for the inheritance of the "DDK syndrome" predicted transmission-ratio distortion through F1 females, we reconsidered the possibility that the genes encoding the maternal and paternal components of this phenotype were not linked. We have examined the fertility phenotype of N2 females and demonstrate that the inter-strain fertility of these females is correlated with their genotype in the Om region. This result establishes, directly, that the genes encoding the maternal and paternal components of the DDK syndrome are genetically linked.

The maternal DDK syndrome phenotype is determined by modifier genes that are not linked to Om.

The DDK syndrome is a polar, early embryonic lethal phenotype caused by incompatibility between a maternal factor of DDK origin and a paternal gene of non-DDK origin. Both maternal factor and paternal gene have been mapped to the Om locus on mouse Chromosome (Chr) 11. The paternal contribution to the syndrome has been shown to segregate as a single locus. Although the inheritance of the maternal contribution has not been characterized in depth, it as been assumed to segregate as a single locus. We have now characterized the segregation of the DDK fertility phenotype in over 240 females. Our results demonstrate that females require at least one DDK allele at Om to manifest the syndrome. However, the DDK syndrome inter-strain cross-fertility phenotype of heterozygous females is highly variable and spans the gamut from completely infertile to completely fertile. Our results indicate that this phenotypic variability has a genetic basis and that the modifiers of the DDK syndrome segregate independently of Om.

A progressive autosomal recessive cataract locus maps to chromosome 9q13-q22.

Cataracts are the leading cause of blindness in most countries. Although most hereditary cases appear to follow an autosomal dominant pattern of inheritance, autosomal recessive inheritance has been clearly documented and is probably underrecognized. We studied a large family-from a relatively isolated geographic region-whose members were affected by autosomal recessive adult-onset pulverulent cataracts. We mapped the disease locus to a 14-cM interval at a novel disease locus, 9q13-q22 (between markers D9S1123 and D9S257), with a LOD score of 4.7. The study of this progressive and age-related cataract phenotype may provide insight into the cause of the more common sporadic form of age-related cataracts.

Transmission-ratio distortion of X chromosomes among male offspring of females with skewed X-inactivation.

We have begun a search for heritable variation in X-chromosome inactivation pattern in normal females to determine whether there is a genetic effect on the imprinting of X-chromosome inactivation in humans. We have performed a quantitative analysis of X-chromosome inactivation in lymphocytes from mothers in normal, three-generation families. Eight mothers and 12 grandmothers exhibited evidence of highly skewed patterns of X-chromosome inactivation. We observed that the male offspring of females with skewed X-inactivation patterns were three times more likely to inherit alleles at loci that were located on the inactive X chromosome (Xi) than the active X chromosome (Xa). The region of the X chromosome for which this phenomenon was observed extends from Xp11 to -Xq22. We have also examined X-chromosome inactivation patterns in 21 unaffected mothers of male bilateral sporadic retinoblastoma patients. Six of these mothers had skewed patterns of X-chromosome inactivation. In contrast to the tendency for male offspring of skewed mothers from nondisease families to inherit alleles from the inactive X chromosome, five of the six affected males inherited the androgen receptor alleles from the active X chromosome of their mother.

Contributions to the study of the etiology of serofibrinous pleurisy in Romania, under the present epidemiological conditions. Evaluation of the etiological role of viruses.

A number of 56 serofibrinous pleurisy cases were subjected to several usual diagnostic tests, as well as to virological investigations. Significant rises in serum antibody titers to different viruses were recorded in 25 cases; the presence of virus antigens in cells from the pleural fluid could be visualized by immunofluorescence in 11 patients. In many cases there was evidence suggesting multiple viral infection. The contribution of various investigation methods to differential diagnosis is discussed and the etiological patterns specific to different territories are outlined.

Localization of a recessive gene for North American Indian childhood cirrhosis to chromosome region 16q22-and identification of a shared haplotype.

North American Indian childhood cirrhosis (NAIC, or CIRH1A) is an isolated nonsyndromic form of familial cholestasis reported in Ojibway-Cree children and young adults in northwestern Quebec. The pattern of transmission is consistent with an autosomal recessive mode of inheritance. To map the NAIC locus, we performed a genomewide scan on three DNA pools of samples from 13 patients, 16 unaffected siblings, and 22 parents from five families. Analysis of 333 highly polymorphic markers revealed 3 markers with apparent excess allele sharing among affected individuals. Additional mapping identified a chromosome 16q segment shared by all affected individuals. When the program FASTLINK/LINKAGE was used and a completely penetrant autosomal recessive mode of inheritance was assumed, a maximum LOD score of 4.44 was observed for a recombination fraction of 0, with marker D16S3067. A five-marker haplotype (D16S3067, D16S752, D16S2624, D16S3025, and D16S3106) spanning 4.9 cM was shared by all patients. These results provide significant evidence of linkage for a candidate gene on chromosome 16q22.