Rotational Spectra of Unsaturated Carbon Chains Produced by Pyrolysis: The Case of Propadienone, Cyanovinylacetylene, and Allenylacetylene

Several interstellar molecules are highly reactive unsaturated carbon chains, which are unstable under terrestrial conditions. Laboratory studies in support of their detection in space thus face the issue of how to produce these species and how to correctly model their rotational energy levels. In this work, we introduce a general approach for producing and investigating unsaturated carbon chains by means of selected test cases. We report a comprehensive theoretical/experimental spectroscopic characterization of three species, namely, propadienone, cyanovinylacetylene, and allenylacetylene, all of them being produced by means of flash vacuum pyrolysis of a suitable precursor. For each species, quantum-chemical calculations have been carried out with the aim of obtaining accurate predictions of the missing spectroscopic information required to guide spectral analysis and assignment. Rotational spectra of the title molecules have been investigated up to 400 GHz by using a frequency-modulation millimeter-/submillimeter-wave spectrometer, thus significantly extending spectral predictions over a wide range of frequency and quantum numbers. A comparison between our results and those available in the literature points out the clear need of the reported laboratory measurements at higher frequencies for setting up accurate line catalogs for astronomical searches.

Genetic and epigenetic associations to obesity-related appetite phenotypes among African-American children

BACKGROUND

Genetic and epigenetic variations may be an important contributer to altered eating behaviors in childhood which may lead to weight gain and obesity later in life.

OBJECTIVE

This study aimed to evaluate epigenetic as well as genetic associations with appetite in young children.

SUBJECTS AND METHODS

Participants were 32 non-obese and 32 obese African-American children aged 5-6 years. Saliva was collected from each child, and RNA and DNA were extracted for analysis. Individuals were genotyped for eating- and obesity-associated single nucleotide polymorphisms in seven candidate genes (FTO, MAOA, SH2B1, LEPR, DNMT3B, BDNF and CCKAR), and DNA methylation levels were measured in the upstream promoter region of each. Transcript levels of MAOA and FTO were also assessed. The Children's Eating Behavior Questionnaire (CEBQ) was used to assess the aspects of appetite. Child obesity was assessed using measured height and weight, and percent body fat was measured by dual-energy X-ray absorptiometry.

RESULTS

Food responsiveness was higher and satiety responsiveness was lower among obese than non-obese female children (P = 0.001 and P = 0.031), but did not differ among male children. Epigenetic analysis of the BDNF promoter revealed associations with altered satiety responsiveness among female children (P < 0.01).

CONCLUSION

The findings provide new evidence of epigenetic associations with altered appetite among young African-American girls.

Liver fibrosis: evaluation with diffusion-weighted magnetic resonance imaging in patients with chronic liver disease

AIM

Liver fibrosis is often a possible evolution of chronic liver disease (CLD), with a risk of progression to cirrhosis. This study was designed to determine if the measure of apparent diffusion coefficient (ADC) is clinically accurate in the staging of fibrosis.

METHODS

The study was conducted in the period 2008-2012. We recruited 84 patients with CLD. The control group included 67 patients whose laboratory, ultrasound and magnetic resonance imaging exams demonstrated liver's normal conditions. For ethical reasons, these patients did not undergo liver biopsy. Patients were examined using diffusion-weighted magnetic resonance imaging with a 1.5 Tesla magnet and with single shot echo-planar technique. Patients did undergo liver biopsy and the samples were evaluated with the Metavir score (F0-F4), Ishak score (0-6) and Brunt score (0-6). Patients were divided into three groups according to the different degree of fibrosis and the ADC was compared with U-test of Mann-Whitney. Moreover, it was used the analysis Receiver Operating Characteristic (ROC).

RESULTS

A significant difference between group 1 (F0-F1) and group 3 (F3-F4) was found, with P=0.0024 and between group 2 (F2) and group 3, with P=0.027, but there was no significant difference of the ADC values in group 1 and group 2.

CONCLUSION

The study showed a correlation between reduction of ADC and increasing of liver fibrosis degree. The ADC seems to be useful in staging liver fibrosis in patients with CLD, in particular to distinguish the later stages of fibrosis from early and intermediate stages.

Expiratory Muscle Strength Training

Purpose. This study investigated the effect of expiratory muscle strength training (EMST) on voice production, dysarthria, and voice-related quality-of-life issues in persons with multiple sclerosis (PwMS). It was hypothesized that PwMS would have improved voice production and reduced voice-related quality-of-life issues following EMST. Participants and Methods. Seventeen participants with MS and 14 healthy (H) controls completed 8 weeks of EMST, followed by 4 weeks of no training. Analyzed outcomes as a function of EMST were maximal expiratory pressure (MEP), sustained vowel prolongation (SVP), words per minute (WPM) measured from connected speech, and quality-of-life indices related to the presence of the dysarthria and dysphonia. Results. PwMS had lower MEPs, shorter SVP, and less WPM than the controls prior to training. Following EMST, both groups had significant improvement in MEPs that stayed above baseline after training halted. EMST did not improve voice production or voice-related quality of life for PwMS. Conclusion. Respiratory muscle weakness is present in PwMS having mild- to moderate-level disability. EMST improved expiratory muscle strength but did not statistically change objective and subjective components of voice/speech production in PwMS.

Laryngostroboscopic, acoustic, and environmental characteristics of high-risk vocal performers

Vocal performance often requires excessively high vocal demand. In particular "high-risk" performers, a group of individuals who use their voices at their maximum effort level, are often exposed to unique vocal abuse characteristics which include high environmental and performance demands and inconsistencies of cast performance. Three categories of high-risk performers were studied: musical theater, choral ensemble, and street theater. Musical theater performers produce a Broadway, West End "belting" style voice. Street theater performers use a high-energy pitch varying dialogue in order to imitate a desired character voice. Choral ensemble performance requires group cohesion and blending of four-part harmony. The melodies require sustained vocal durations within each of the respective registers. For each of these studied groups vocal tasks of sustained production of /i/ and /a/ were subjected to analysis. Acoustic measures included fundamental frequency, standard deviation of fundamental frequency, jitter percent, shimmer percent, and noise-to-harmonic ratio. Laryngostroboscopic parameters were assessed during sustained /i/. Environmental acoustic sound field measurements were made using an A weighting and linear weighting sound pressure level. These weightings were used to describe noise levels and vocal output, respectively, within the performance environments. Results of the analysis suggest that high-risk performers are a unique performance type defined by distinctive, acoustic, laryngostroboscopic, and environmental characteristics.

Female meiosis drives karyotypic evolution in mammals

Speciation is often accompanied by changes in chromosomal number or form even though such changes significantly reduce the fertility of hybrid intermediates. We have addressed this evolutionary paradox by expanding the principle that nonrandom segregation of chromosomes takes place whenever human or mouse females are heterozygous carriers of Robertsonian translocations, a common form of chromosome rearrangement in mammals. Our analysis of 1170 mammalian karyotypes provides strong evidence that karyotypic evolution is driven by nonrandom segregation during female meiosis. The pertinent variable in this form of meiotic drive is the presence of differing numbers of centromeres on paired homologous chromosomes. This situation is encountered in all heterozygous carriers of Robertsonian translocations. Whenever paired chromosomes have different numbers of centromeres, the inherent asymmetry of female meiosis and the polarity of the meiotic spindle dictate that the partner with the greater number of centromeres will attach preferentially to the pole that is most efficient at capturing centromeres. This mechanism explains how chromosomal variants become fixed in populations, as well as why closely related species often appear to have evolved by directional adjustment of the karyotype toward or away from a particular chromosome form. If differences in the ability of particular DNA sequences or chromosomal regions to function as centromeres are also considered, nonrandom segregation is likely to affect karyotype evolution across a very broad phylogenetic range.

Nonrandom segregation during meiosis: the unfairness of females

Most geneticists assume that chromosome segregation during meiosis is Mendelian (i.e., each allele at each locus is represented equally in the gametes). The great majority of reports that discuss non-Mendelian transmission have focused on systems of gametic selection, such as the mouse t-haplotype and Segregation distorter in Drosophila, or on systems in which post-fertilization selection takes place. Because the segregation of chromosomes in such systems is Mendelian and unequal representation of alleles among offspring is achieved through gamete dysfunction or embryonic death, there is a common perception that true disturbances in the randomness of chromosome segregation are rare and of limited biological significance. In this review we summarize data on nonrandom segregation in a wide variety of genetic systems. Despite apparent differences between some systems, the basic requirements for nonrandom segregation can be deduced from their shared characteristics: i) asymmetrical meiotic division(s); ii) functional asymmetry of the meiotic spindle poles; and iii) functional heterozygosity at a locus that mediates attachment of a chromosome to the spindle. The frequency with which all three of these requirements are fulfilled in natural populations is unknown, but our analyses indicate that nonrandom segregation occurs with sufficient frequency during female meiosis, and in exceptional cases of male meiosis, that it has important biological, clinical, and evolutionary consequences.

Transmission ratio distortion in offspring of heterozygous female carriers of Robertsonian translocations

Robertsonian translocations are the most common structural rearrangements of human chromosomes. Although segregation of Robertsonian chromosomes has been examined in many families, there is little consensus on whether inheritance in the balanced progeny conforms to Mendelian ratios. To address this question, we have compiled previously reported segregation data, by sex of parent, for 677 balanced offspring of Robertsonian carriers from 82 informative families and from a prenatal diagnosis study on the risk of unbalanced offspring in carriers of chromosome rearrangements. Care was taken to avoid any source of ascertainment bias. Our analysis supports the following conclusions: (1) the transmission ratio is not independent of the sex of the carrier; (2) the transmission ratio distortion is observed consistently only among the offspring of carrier females; (3) the transmission ratio distortion does not appear to be dependent on the presence of a specific acrocentric chromosome in the rearrangement. The sex-of-parent-specific origin of the non-Mendelian inheritance, the finding that the rearranged ("mutant") chromosomes are recovered at significantly higher frequency than the acrocentric ("normal") chromosomes, and the similarities between these observations and the segregation of analogous rearrangements through female meiosis in other vertebrates strongly support the hypothesis that the transmission ratio distortion in favor of Robertsonian translocations in the human results from the preferential segregation of chromosomes during the first meiotic division. This non-Mendelian inheritance will result in increased overall risk of aneuploidies in the families of Robertsonian translocation carriers, independently of the origin of the transmission ratio distortion.

Natural selection and the function of genome imprinting: beyond the silenced minority

Most hypotheses of the evolutionary origin of genome imprinting assume that the biochemical character on which natural selection has operated is the expression of the allele from only one parent at an affected locus. We propose an alternative - that natural selection has operated on differences in the chromatin structure of maternal and paternal chromosomes to facilitate pairing during meiosis and to maintain the distinction between homologues during DNA repair and recombination in both meiotic and mitotic cells. Maintenance of differences in chromatin structure in somatic cells can sometimes result in the transcription of only one allele at a locus. This pattern of transcription might be selected, in some instances, for reasons that are unrelated to the original establishment of the imprint. Differences in the chromatin structure of homologous chromosomes might facilitate pairing and recombination during meiosis, but some such differences could also result in non-random segregation of chromosomes, leading to parental-origin-dependent transmission ratio distortion. This hypothesis unites two broad classes of parental origin effects under a single selective force and identifies a single substrate through which Mendel's first and second laws might be violated.

Heritability of the maternal meiotic drive system linked to Om and high-resolution mapping of the Responder locus in mouse

Matings between (C57BL/6 x DDK)F(1) females and C57BL/6 males result in a significant excess of offspring inheriting maternal DDK alleles in the central region of mouse chromosome 11 due to meiotic drive at the second meiotic division. We have shown previously that the locus subject to selection is in the vicinity of D11Mit66, a marker closely linked to the Om locus that controls the preimplantation embryo-lethal phenotype known as the "DDK syndrome." We have also shown that observation of meiotic drive in this system depends upon the genotype of the sire. Here we show that females that are heterozygous at Om retain the meiotic drive phenotype and define a 0.32-cM candidate interval for the Responder locus in this drive system. In addition, analysis of the inheritance of alleles at Om among the offspring of F(1) intercrosses indicates that the effect of the sire is determined by the sperm genotype at Om or a locus linked to Om.

Male-offspring-specific, haplotype-dependent, nonrandom cosegregation of alleles at loci on two mouse chromosomes

F(1) backcrosses involving the DDK and C57BL/6 inbred mouse strains show transmission ratio distortion at loci on two different chromosomes, 11 and X. Transmission ratio distortion on chromosome X is restricted to female offspring while that on chromosome 11 is present in offspring of both sexes. In this article we investigate whether the inheritance of alleles at loci on one chromosome is independent of inheritance of alleles on the other. A strong nonrandom association between the inheritance of alleles at loci on both chromosomes is found among male offspring, while independent assortment occurs among female offspring. We also provide evidence that the mechanism by which this phenomenon occurs involves preferential cosegregation of nonparental chromatids of both chromosomes at the second meiotic division, after the ova has been fertilized by a C57BL/6 sperm bearing a Y chromosome. These observations confirm the influence of the sperm in the segregation of chromatids during female meiosis, and indicate that a locus or loci on the Y chromosome are involved in this instance of meiotic drive.

A genetic test to determine the origin of maternal transmission ratio distortion. Meiotic drive at the mouse Om locus

We have shown previously that the progeny of crosses between heterozygous females and C57BL/6 males show transmission ratio distortion at the Om locus on mouse chromosome 11. This result has been replicated in several independent experiments. Here we show that the distortion maps to a single locus on chromosome 11, closely linked to Om, and that gene conversion is not implicated in the origin of this phenomenon. To further investigate the origin of the transmission ratio distortion we generated a test using the well-known effect of recombination on maternal meiotic drive. The genetic test presented here discriminates between unequal segregation of alleles during meiosis and lethality, based on the analysis of genotype at both the distorted locus and the centromere of the same chromosome. We used this test to determine the cause of the transmission ratio distortion observed at the Om locus. Our results indicate that transmission ratio distortion at Om is due to unequal segregation of alleles to the polar body at the second meiotic division. Because the presence of segregation distortion at Om also depends on the genotype of the sire, our results confirm that the sperm can influence segregation of maternal chromosomes to the second polar body.

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.

Respiratory-related evoked potential elicited by expiratory occlusion

Respiratory-related evoked potentials (RREPs) have been elicited by inspiratory loads in adults and children. The RREP was recorded over the somatosensory region of the cerebral cortex. It was hypothesized that a RREP could be recorded by using expiratory occlusion. Electroencephalographic activity was recorded in adults from 14 scalp locations, referenced to the linked earlobes. The occlusion was presented as an interruption of expiration. Epochs of electroencephalographic activity and mouth pressure were recorded for each expiratory occlusion presentation. There were two occlusion trials and a control trial of 100 presentations each. The epochs in each trial were averaged and examined for the presence of short-latency, occlusion-related peaks. RREP peaks were observed bilaterally with expiratory occlusion and were absent in control unoccluded averages. A positive peak, P(34), was observed at central and postcentral sites. A negative peak, N(53), was observed at frontal and central sites. A second positive peak, P(95), was observed at frontal and central sites. These results demonstrate that expiratory occlusion elicits a RREP. This suggests that expiratory occlusion-related sensory information activates the cerebral cortex similar to that for inspiratory loads.

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.

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.

Parental origin-dependent, male offspring-specific transmission-ratio distortion at loci on the human X chromosome

We have analyzed the transmission of maternal alleles at loci spanning the length of the X chromosome in 47 normal, genetic disease-free families. We found a significant deviation from the expected Mendelian 1:1 ratio of grandpaternal:grandmaternal alleles at loci in Xp11.4-p21.1. The distortion in inheritance ratio was found only among male offspring and was manifested as a strong bias in favor of the inheritance of the alleles of the maternal grandfather. We found no evidence for significant heterogeneity among the families, which implies that the major determinant involved in the generation of the non-Mendelian ratio is epigenetic. Our analysis of recombinant chromosomes inherited by male offspring indicates that an 11.6-cM interval on the short arm of the X chromosome, bounded by DXS538 and DXS7, contains an imprinted gene that affects the survival of male embryos.

The M31 gene has a complex developmentally regulated expression profile and may encode alternative protein products that possess diverse subcellular localisation patterns

HP1-like chromobox genes comprise an evolutionarily conserved family of genes that encode components of centromeric heterochromatin. In order to investigate the role of the murine HP1-like gene, M31, in heterochromatin formation we have isolated its gene and characterised its transcripts and protein products. PCR products that represent M31 transcripts were detected at the one-cell stage and were maternal in origin. Maternal provision of M31 transcripts may reflect a need for M31 in the formation of a functional centromere in order that there is proper segregation of chromosomes during the early cleavage divisions; studies in fission yeast and Drosophila have suggested a crucial role for HP1-like genes in centromere function. There are three protein products encoded by the M31 gene. Surprisingly, the two smaller products are found almost exclusively in the cytoplasm.

Localization of genes encoding egg modifiers of paternal genome function to mouse chromosomes one and two

It is now well established that genomic imprinting effects in mammals require a combination of epigenetic modifications imposed during gametogenesis and additional modifications imposed after fertilization. The earliest post-fertilization modifications to be imposed on the genome are those thought to be mediated by factors in the egg cytoplasm. Strain-dependent differences in the actions of these egg modifiers in mice reveal an important potential for genetic variability in the imprinting process, and also provide valuable genetic systems with which to identify some of the factors that participate in imprinting. Previous studies documented a strain-dependent difference in the modification of paternal genome function between the C57BL/6 and DBA/2 mouse strains. This difference is revealed as a difference in developmental potential of androgenetic embryos produced with eggs from females of the two strains by nuclear transplantation. The specificity of the effect for the paternal genome is consistent with an effect on imprinted genes. The egg phenotype is largely independent of the genotype of the fertilizing sperm, and the C57BL/6 phenotype is dominant in reciprocal F1 hybrids. Genetic studies demonstrated that the difference in egg phenotypes between the two strains is most likely controlled by two independently segregating loci. We now report the results of experiments in which the egg phenotypes of the available BxD recombinant inbred mouse strains have been determined. The results of the analysis are consistent with the two locus model, and we have identified candidate chromosomal locations for the two loci. These data demonstrate clearly that differences in how the egg cytoplasm modifies the incoming paternal genome are indeed genetically determined, and vary accordingly.

A promoter mutation in the XIST gene in two unrelated families with skewed X-chromosome inactivation

X-chromosome inactivation is the process by which a cell recognizes the presence of two copies of an X chromosome early in the development of XX embryos and chooses one to be active and one to be inactive. Although it is commonly believed that the initiation of X inactivation is random, with an equal probability (50:50) that either X chromosome will be the inactive X in a given cell, significant variation in the proportion of cells with either X inactive is observed both in mice heterozygous for alleles at the Xce locus and among normal human females in the population. Families in which multiple females demonstrate extremely skewed inactivation patterns that are otherwise quite rare in the general population are thought to reflect possible genetic influences on the X-inactivation process. Here we report a rare cytosine to guanine mutation in the XIST minimal promoter that underlies both epigenetic and functional differences between the two X chromosomes in nine females from two unrelated families. All females demonstrate preferential inactivation of the X chromosome carrying the mutation, suggesting that there is an association between alterations in the regulation of XIST expression and X-chromosome inactivation.

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.

Heritability of X chromosome--inactivation phenotype in a large family

One of the two X chromosomes in each somatic cell of normal human females becomes inactivated very early in embryonic development. Although the inactivation of an X chromosome in any particular somatic cell of the embryonic lineage is thought to be a stochastic and epigenetic event, a strong genetic influence on this process has been described in the mouse. We have attempted to uncover evidence for genetic control of X-chromosome inactivation in the human by examining X chromosome-inactivation patterns in 255 females from 36 three-generation pedigrees, to determine whether this quantitative character exhibits evidence of heritability. We have found one family in which all seven daughters of one male and the mother of this male have highly skewed patterns of X-chromosome inactivation, suggesting strongly that this quantitative character is controlled by one or more X-linked genes in some families.

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.

Chromosomal localization of mouse and human genes encoding the splicing factors ASF/SF2 (SFRS1) and SC-35 (SFRS2)

The mammalian SR-type splicing factors ASF/SF2 and SC-35 play crucial roles in pre-mRNA splicing and have been shown to shift splice site choice in vitro. We have mapped the ASF/SF2 gene in mice and humans and the SC-35 gene in mice. Somatic cell hybrid mapping of the human ASF/SF2 gene (SFRS1 locus) reveals that it resides on chromosome 17, and fluorescence in situ hybridization refines this localization to 17q21.3-q22. Recombinant inbred mapping of the mouse ASF/SF2 gene (Sfrs1 locus) and the mouse SC-35 gene (Sfrs2 locus) demonstrates that both genes are located in a part of mouse chromosome 11 that is homologous to human chromosome 17. Mapping of Sfrs1 using F1 hybrid backcross mice between the strains C57BL/6 and DDK places Sfrs1 very near the marker D11Mit38 and indicates that the ASF/SF2 gene is closely linked to the Ovum mutant locus.

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.

Articulatory, developmental, and gender effects on measures of fundamental frequency and jitter

Fundamental frequency (Fo) and jitter were measured in digitized live-voice productions of sustained vowels [a], [i], and [u] from women, men, and 6- through 9-year-old children. Results showed (a) significant developmental differences for mean Fo and for the pattern of jitter by vowel type, (b) significant gender differences in Fo and jitter only for adults, (c) significant differences in Fo and jitter according to vowel type for all subjects, and (d) similar amounts of mean absolute jitter for children and women for all vowels with nonsignificantly different values of jitter for boys and men on [i] and [u] productions. Results are related to Honda's theory of intrinsic Fo for vowels and to Titze's neurologic model of jitter.

The genetics of retinoblastoma, revisited

Our epidemiological and genetic analyses of sporadic and familial retinoblastoma indicate that an X-chromosome-linked gene is involved in the genesis of a significant fraction of new bilateral cases of the disease. The activity of this gene results in sex-ratio distortion in favor of males among patients with bilateral sporadic disease. Among the offspring of these males, both sex-ratio distortion in favor of males and transmission-ratio distortion in favor of affecteds are observed. We propose that these phenomena are due to the inability of these males to erase the genome imprint established on the half of the genome inherited from their mothers.

Respiratory and laryngeal measures of children during vocal intensity variation

Simultaneous aerodynamic, acoustic, and kinematic measurements from the laryngeal and respiratory systems were made in order to study mechanisms for changing vocal intensity. Aerodynamic and acoustic measures include an approximation of open quotient, maximum flow declination rate, alternating glottal airflow, estimated tracheal pressure, sound pressure level, and fundamental frequency. Respiratory measures included lung volume, rib cage, and abdominal displacements. Adults were used as a comparison group to twenty 4-year-olds and twenty 8-year-olds. Laryngeal and respiratory results indicate that speech production differences between the children and adults are based both on size and function. For example, children's absolute anteroposterior diameters of the rib cage are smaller than adults, but their rib cage movement is larger and encompasses a different range during speech breathing. Since children are functionally different than adults, age specific speech production models need to be developed.

Preferential amplification of the paternal allele of the N-myc gene in human neuroblastomas

Genomic imprinting plays a role in influencing the parental origin of genes involved in cancer-specific rearrangements. We have analysed 22 neuroblastomas with N-myc amplification to determine the parental origin of the amplified N-myc allele and the allele that is deleted from chromosome 1p. We analysed DNA from neuroblastoma patients and their parents, using four polymorphisms for 1p and three for the N-myc amplicon. We determined that the paternal allele of N-myc was preferentially amplified (12 out of 13 cases; P = 0.002). However, the paternal allele was lost from 1p in six out of ten cases, consistent with a random distribution (P > 0.2). These results suggest that parental imprinting influences which N-myc allele is amplified in neuroblastomas, but it does not appear to affect the 1p allele that is deleted in the cases that we have examined.

Respiratory and laryngeal function of women and men during vocal intensity variation

Simultaneous procedures for making aerodynamic and kinematic observations of the laryngeal and chest wall systems were used to investigate variations in vocal intensity in normal women and men. Laryngeal results indicate that significant increases of maximum flow declination rate and laryngeal airway resistance and significant decreases in open quotient occur when higher intensity levels are produced. Respiratory results indicate that tracheal pressure, percent rib cage contribution, lung volume, and rib cage volume initiations are higher, and lung and rib cage volume excursions are larger when higher vocal intensity levels are produced. Laryngeal and respiratory function results indicate that some measures are different for women than for men. Mean data support the notion that increases in tracheal pressure are achieved by inhaling to higher lung and rib cage volumes. Individual subject data provide alternative respiratory and laryngeal patterns for changing the shape of the glottal airflow waveform.

[Treatment of postoperative entero-cutaneous fistula: personal experience]

The authors present their experience on surgical treatment of intestinal fistulas based on personal cases treated from 1981 to 1990. The cases are divided into two groups: the first: the first group of patients was treated only surgically (1981-1984); the second group was treated with surgery and artificial nutrition (1984-1990). The mortality rates are much lower in the second group. The conclusion is that is always necessary to associate a form of artificial nutrition to surgery because the percentage of healing is statistically higher.

The polar-lethal Ovum mutant gene maps to the distal portion of mouse chromosome 11

Genome imprinting is the process by which identical alleles at a particular locus may be rendered functionally different depending on the sex of the parent contributing the allele. While several mutations in imprinted genes have been defined, no variants in the regulatory system that gives rise to imprinting have been described. Here we report our genetic analysis of the behavior of the interstrain, polar, embryonic-lethal phenotype known as the "DDK syndrome." We have mapped the interstrain, polar-lethal region of the genome to the distal portion of mouse chromosome 11, near the Xmv-42 locus. We propose that the lethal phenotype is not caused by a standard mutation, but by aberrant imprinting of a gene within this region.

Genome imprinting and cancer genetics

Parent-of-origin-dependent modification of the genome (genome imprinting) is thought to be involved in the formation of several types of human cancer. Simple modifications of Knudson's two-hit model give rise to two types of predictions with respect to the genetic behavior of such diseases. In the first, rare alleles of modifier genes will give rise to the retention of the same parent's tumor suppressor alleles in sporadic cases. In the second, other variants of the modifier genes will result in failure to establish linkage between tumor suppressor genes and disease predisposition in familial cases. Both of these predictions are fulfilled by experiment. Additional modifications of existing models are predicted to result in more complex patterns of inheritance. The demonstration of such patterns in human pedigrees will require an extremely sophisticated level of genetic analysis.

Loss of heterozygosity for chromosomes 1 or 14 defines subsets of advanced neuroblastomas

Neuroblastomas have been characterized genetically by N-myc amplification and by deletions or loss of heterozygosity (LOH) for the short arm of chromosome 1. However, recent studies have suggested deletion or allelic loss involving at least three other chromosome arms, 11q, 14q, and 17p. Therefore, we undertook an analysis of allelic loss for these respective chromosomal arms to determine the frequency and pattern of LOH as well as the correlation of these findings with other biological and clinical variables. A group of 24 pairs of normal and tumor DNAs was chosen that were representative of patients of different ages and stages. A substantial frequency of LOH (greater than or equal to 20%) was found only for 1p and 14q, whereas LOH for the other chromosome arms occurred in less than or equal to 5% of cases. On the basis of these results, we extended the analysis to a total of 59 neuroblastomas, and we found 1p LOH in 15 of the 59 cases (25%) and 14q LOH in 10 of 43 informative cases (23%). N-myc amplification was found in 15 of the 59 cases (25%). This analysis confirmed that 1p LOH and 14q LOH occurred almost exclusively in patients with advanced stages of disease. Furthermore, LOH for 1p and 14q usually occurred independent of each other, and 1p LOH frequently was associated with N-myc amplification, whereas 14q LOH was not. Thus, our results demonstrate that neuroblastomas are complex genetically and that there are at least two distinct loci for putative suppressor genes that are deleted independently in this tumor, both of which are associated with advanced stages of disease.