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Biomedical subjects

M Ron

Publications and source records attributed to M Ron.

At least 37 records · Page 2Linked to original sources
PubMed2001

Multiple quantitative trait locus analysis of bovine chromosome 6 in the Israeli Holstein population by a daughter design.

Nine Israeli Holstein sire families with 2978 daughters were analyzed for quantitative trait loci effects on chromosome 6 for five milk production traits by a daughter design. All animals were genotyped for 2 markers. The three families with significant effects were genotyped for up to 10 additional markers spanning positions 0-122 cM of BTA6. Two sires were segregating for a locus affecting protein and fat percentage near position 55 cM with an estimated substitution effect of 0.18% protein, which is equivalent to one phenotypic standard deviation. This locus was localized to a confidence interval of 4 cM. One of these sires was also heterozygous for a locus affecting milk, fat, and protein production near the centromere. The hypothesis of two segregating loci was verified by multiple regression analysis. A third sire was heterozygous for a locus affecting milk and protein percentage near the telomeric end of the chromosome. Possible candidates for the major quantitative gene near position 55 cM were determined by comparative mapping. IBSP and SSP1 were used as anchors for the orthologous region on human chromosome 4. Twelve genes were detected within a 2-Mbp sequence. None of these genes have been previously associated with lactogenesis.

Animals↗
PubMed2001

Structural abnormalities in frontal, temporal, and limbic regions and interconnecting white matter tracts in schizophrenic patients with prominent negative symptoms.

OBJECTIVE: Imaging studies of schizophrenia have repeatedly demonstrated global abnormalities of cerebral and ventricular volumes. However, pathological changes at more local levels of brain organization have not yet been so clearly characterized because of the few brain regions of interest heretofore included in morphometric analyses as well as heterogeneity of patient samples. METHOD: Dual echo magnetic resonance imaging (MRI) data were acquired at 1.5 T from 27 right-handed patients who met DSM-IV criteria for schizophrenia with enduring negative symptoms and from 27 healthy comparison subjects. Between-group differences in gray and white matter volume were estimated at each intracerebral voxel after registration of the images in standard space. The relationship between clinical symptom scores and brain structure was also examined within the patient group. Spatial statistics and permutation tests were used for inference. RESULTS: Significant deficits of gray matter volume in the patient group were found at three main locations: 1) the left superior temporal gyrus and insular cortex, 2) the left medial temporal lobe (including the parahippocampal gyrus and hippocampus), and 3) the anterior cingulate and medial frontal gyri. The volume of these three regions combined was 14% lower in the patients relative to the comparison subjects. White matter deficits were found in similar locations in the left temporal lobe and extended into the left frontal lobe. The patient group showed a relative excess of gray matter volume in the basal ganglia. Within the patient group, basal ganglia gray matter volume was positively correlated with positive symptom scores. CONCLUSIONS: Anatomical abnormalities in these schizophrenic patients with marked negative symptoms were most evident in left hemispheric neocortical and limbic regions and related white matter tracts. These data are compatible with models that depict schizophrenia as a supraregional disorder of multiple, distributed brain regions and the axonal connections between them.

Adult↗
PubMed2001

[Hemoglobin level among infants in Akko sub-district].

OBJECTIVES: To determine the prevalence of anemia among infants born in 1995 within the Akko sub-district and to investigate the association between anemia and socio-demographic variables. SUBJECTS AND METHODS: In 1995, 7920 children were born in the Akko sub-district. Recommendations for prophylactic doses of iron preparations were given to all the infants aged 4-12 months screened by the "Mother and Child" clinic's team. Procedures at the "Mother and Child" clinic require the clinic's nurses to perform a routine hemoglobin test for each child at the age of 12 months. Anemia was defined as a level of hemoglobin less than 11 g/dl. The chi-square test was used for statistical analyses. RESULTS: A hemoglobin test was performed on 5703 infants. The finding showed that 30.8% of these infants had a hemoglobin level below 11 g/dl, 24% had a hemoglobin level between 10.0-10.9 g/dl, 6%--between 9.0-9.9 g/dl and less then 1% of the infants had a level of hemoglobin below 9.0 g/dl. Statistical analysis was performed on the results obtained from 5535 infants of non-Jewish origin. An association was found between the rate of anemia and ethnicity (Arabs more than Druze, p = 0.02) and between the rate of anemia and the type of settlement (p = 0.001). Arab settlements of higher socio-economic level showed a lower rate of anemia than those of low socio-economic level. The highest rate of anemia was found within Bedouin settlements. The number of children in the family was significantly associated with anemia rates (p = 0.0005), showing dose response effect. There was inverse correlation between maternal education and anemia rate (p = 0.001). No association was found between birth weight and anemia rates. CONCLUSIONS: A high rate of anemia was found among non-Jewish infants in the Akko sub-district. This finding indicates the necessity for an intervention program to reduce this high rate of anemia and its associated damage in order to facilitate the optimal psychomotor development of the children.

Anemia↗
PubMed1999

A genome scan for QTL influencing milk production and health traits in dairy cattle.

A genome scan was conducted in the North American Holstein-Friesian population for quantitative trait loci (QTL) affecting production and health traits using the granddaughter design. Resource families consisted of 1,068 sons of eight elite sires. Genome coverage was estimated to be 2,551 cM (85%) for 174 genotyped markers. Each marker was tested for effects on milk yield, fat yield, protein yield, fat percentage, protein percentage, somatic cell score, and productive herd life using analysis of variance. Joint analysis of all families identified marker effects on 11 chromosomes that exceeded the genomewide, suggestive, or nominal significance threshold for QTL effects. Large marker effects on fat percentage were found on chromosomes 3 and 14, and multimarker regression analysis was used to refine the position of these QTL. Half-sibling families from Israeli Holstein dairy herds were used in a daughter design to confirm the presence of the QTL for fat percentage on chromosome 14. The QTL identified in this study may be useful for marker-assisted selection and for selection of a refined set of candidate genes affecting these traits.

Animals↗
PubMed1999

Isolation of a novel SUMO protein from tomato that suppresses EIX-induced cell death.

Challenging tomato or tobacco varieties with ethylene-inducing xylanase (EIX) from the fungus Trichoderma viride causes rapid induction of plant defence responses leading to programmed cell death. Using the yeast two-hybrid system, we isolated a novel protein, tomato small ubiquitin-related modifier protein (T-SUMO), which specifically interacts with EIX. T-SUMO, a cytoplasmic protein, is a member of the ubiquitin-like protein family. It shows homology to human protein sentrin/SUMO1, which suppresses tumour necrosis factor-induced cell death. Transgenic plants that express T-SUMO in the sense orientation suppress EIX induction of ethylene biosynthesis and cell death, while in the antisense orientation they enhance EIX-induced ethylene biosynthesis. These results indicate that T-SUMO is involved in mediating the signal generated by EIX that leads to induction of plant defence responses.

Amino Acid Sequence↗
PubMed1999

Standardization and conversion of marker polymorphism measures.

Large scale gene mapping efforts in domestic animals have generated and mapped a large number of genetic markers that are useful for mapping quantitative trait and disease loci and for DNA diagnostic purposes such as parentage testing. Marker polymorphism is an important criterion for selecting genetic markers in planning experiment for mapping quantitative trait loci or for DNA diagnostic purposes. Current formulations of marker polymorphism measures are functions of marker allele frequencies. In this study, two measures of marker polymorphism that are available from gene mapping studies and do not require allele frequencies were proposed and analyzed: the observed polymorphic information content (PIC) and the observed family information content (FIC). The observed FIC was more stable than the observed PIC because the observed FIC is unaffected by the variation in the frequency of heterozygous parents. However, both FIC and PIC are dependent on the gene mapping design. The effective number of alleles is recommended as a tool to standardize marker polymorphism measures so that polymorphism of different markers can be compared on an equal basis, and to obtain a new polymorphism measure (such an exclusion probability) from an existing measure (such as FIC). The usage of the effective number of alleles to standardize FIC, PIC and exclusion probabilities is illustrated using genetic markers in a published linkage map.

Animals↗
PubMed1998

Determination of allele frequency from DNA pools using bovine trinucleotide microsatellites.

Three sets of fluorescent labelled primers were used to amplify bovine trinucleotide microsatellites from DNA pools. DNA from 20 individuals were collected to create 3 pools differing in allele frequencies. Replicate mixes from each pool were used as template for PCR reactions. PCR products were separated and quantified on an automated DNA sequencer. Allele frequency estimates from pooled samples corrected for overlapping shadow peaks were calculated. Rare alleles representing only 2.5% of the total pool were accurately detected. Standard error of allele frequency estimates expressed as percent of the total 40 chromosomes per pool ranged between 0.8%-4.6% for different microsatellite-pool combinations as compared to 8.0% binomial sampling error. Regression coefficients of actual allele frequencies, determined by individual genotyping, on estimated frequencies ranged from 0.96-1.06. As regression slopes were close to unity it can be deduced that corrected peak height values from a DNA pool are unbiased estimates of actual allele frequencies. With standard error of the y-intercept of 0.21, the 95% confidence interval of allele frequency is 0.42 alleles or 1% in a pool of 40 chromosomes. Thus, it would be possible to detect an allele with a frequency of greater than 1% within the pool.

Alleles↗
PubMed1998

A new approach to the problem of multiple comparisons in the genetic dissection of complex traits.

Saturated genetic marker maps are being used to map individual genes affecting quantitative traits. Controlling the "experimentwise" type-I error severely lowers power to detect segregating loci. For preliminary genome scans, we propose controlling the "false discovery rate," that is, the expected proportion of true null hypotheses within the class of rejected null hypotheses. Examples are given based on a granddaughter design analysis of dairy cattle and simulated backcross populations. By controlling the false discovery rate, power to detect true effects is not dependent on the number of tests performed. If no detectable genes are segregating, controlling the false discovery rate is equivalent to controlling the experimentwise error rate. If quantitative loci are segregating in the population, statistical power is increased as compared to control of the experimentwise type-I error. The difference between the two criteria increases with the increase in the number of false null hypotheses. The false discovery rate can be controlled at the same level whether the complete genome or only part of it has been analyzed. Additional levels of contrasts, such as multiple traits or pedigrees, can be handled without the necessity of a proportional decrease in the critical test probability.

Animals↗
PubMed1998

A longitudinal study of psychosis due to a general medical (neurological) condition: establishing predictive and construct validity.

A sample of 44 patients with a neurological disorder and a DSM-IV diagnosis of Psychosis due to a General Medical Condition were followed on average for 4 years and their response to treatment and clinical course noted. Outcome was more benign than in schizophrenia, with most patients having a brief duration of psychosis and good response to small doses of neuroleptics. One-fourth of patients suffered a single, brief psychotic episode with return to full premorbid function. None required maintenance neuroleptic treatment. The outcome and descriptive profile of the disorder also differed from late-onset schizophrenia. Thus, Psychosis due to a General Medical (Neurological) Condition does appear to have predictive validity. However, no temporal association was found between the neurological illness and psychosis. Possible reasons for this are discussed.

Adult↗
PubMed1997

Focal signal hyperintensities in schizophrenia.

The presence of focal signal hyperintensities on MRI images of the brain was compared in 48 schizophrenic patients, 26 patients with bipolar disorder and 34 healthy controls. Significantly larger areas of brain were affected by focal signal hyperintensities, particularly in the frontal lobes, in the schizophrenic group compared to the bipolar group and the controls. Although the bipolar group had more such foci than controls, this difference did not reach statistical significance.

Adult↗
PubMed1997

Isolation of microsatellites from a bovine YAC clone harbouring the SOD1 gene.

A bovine yeast artificial chromosome (YAC) clone containing the superoxide dismutase 1 (SOD1) gene was used as a template for polymerase chain reaction (PCR) amplification using a conserved short interspersed nuclear element (SINE) primer. Two highly polymorphic microsatellites with nine and eight alleles were isolated and mapped by linkage analysis to the centromeric region of BTA1. These microsatellites will be used in the construction of a genetic and physical map of the SOD1 region towards positional cloning of the polled gene.

Animals↗
PubMed1996

Multiple genotype analysis and sexing of IVF bovine embryos.

Twenty-one in vitro-fertilized bovine blastocysts were quartered, lysed and subjected to primer elongation preamplification (PEP) procedure, allowing for the analysis of up to 40 genotypes per quarter embryo. The quarter-embryos were sexed by polymerase chain reaction (PCR) using BRY.1, Bov97M and ZFX/ZFY loci, and then genotyped for k-casein, bovine leukocyte adhesion deficiency (BLAD) and microsatellite D9S1. The mitochondrial cytochrome B locus was used as an internal control with a 95% success rate. The PEP procedure amplified genomic fragments in 93% of all cases. The embryos were identified to be 11 males and 10 females. Sexing accuracy was 87% for BRY.1, 97% for ZFX/ZFY and 100% for Bov97M. False genotyping was due mostly to amplification of BRY.1 in the female embryos and to the nonamplification of the ZFY locus in the male embryos. The results indicate that the combined use of Bov97M and ZFX/ZFY loci is a highly accurate procedure for sexing bovine embryos. Genotyping for kappa-casein, D9S1 and BLAD was successful in 94, 99 and 91% of assays, respectively. Sex ratios and allele frequencies of embryos for gk-casein, BLAD and D9S1 were all close to the observed frequencies in the Israeli Holstein population. These results support the conclusion that the genotyping of embryos is as accurate as that of mature animals. Thus, marker-assisted selection can be efficiently applied at the preimplantation embryo level for loci of economic importance.

Journal Article↗
PubMed1996

Resolution of left hemisphere cognitive dysfunction in multiple sclerosis with magnetic resonance correlates: a case report.

Cognitive impairment is common in multiple sclerosis and although deterioration has been observed in individual patients at the time of relapse, improvement in cognitive function in parallel with remission of neurological impairment has proved more difficult to document. We describe a 21-year-old women with a one-year history of relapsing remitting multiple sclerosis, who was admitted to hospital following a severe relapse which rendered her quadriplegic. Detailed psychometric assessment was carried out during relapse and on recovery of neurological function, eight weeks later. There were improvements in arithmetic, naming, and comprehension tasks. The patient had T2 weighted and gadolinium-enhanced magnetic resonance imaging and magnetic resonance spectroscopy. These showed a reduction in lesion size, lesion enhancement, and changes in brain chemistry which parallel the improvement in cognitive performance.

Journal Article↗
PubMed1996

Creation of a SINE enriched library for the isolation of polymorphic (AGC)n microsatellite markers in the bovine genome.

Trinucleotide (AGC)n microsatellites are found as 3' tails of the artiodactyl short insterspersed nuclear element (SINE) A-dimer. We describe a polymerase chain reaction (PCR)-based method for the construction of a plasmid library enriched for SINE (AGC)n microsatellites. By amplifying Sau3AI inserts with a conserved SINE primer and a flanking vector primer, a 35-fold enrichment of (AGC)n microsatellites over a conventional genomic library was obtained. The SINE primer was used for both sequencing of AGC-containing inserts and analysis of polymorphism. Twenty-three unique reverse primers were synthesized and used on bovine genomic DNA, 21 producing PCR products of expected size. Five polymorphic (AGC)n microsatellites with 2-4 alleles each were characterized. Allele sizes differed by a 3 bp motif and lacked the stutter bands associated with dinucleotide repeats. A tendency of increased polymorphism for longer AGC repeat arrays was observed. High stringency selection for positive clones containing eight or more AGC repeats can thus facilitate the isolation of polymorphic (AGC)n microsatellites. Enrichment for (AGC)n microsatellites by SINE-vector PCR can be applied to other bovidae species, such as sheep or goat, containing the artiodactyl SINE elements.

Animals↗
PubMed1996

Misidentification rate in the Israeli dairy cattle population and its implications for genetic improvement.

The DNA microsatellites can be efficiently used to determine incorrect paternity attribution of cattle without genotyping of dams. Allelic frequencies of the population were determined for 12 microsatellites using the maternal alleles of 102 AI sires. The frequency of the most common microsatellite allele ranged from 0.27 to 0.58. Most loci had at least one allele that was present in only a single individual. Paternity of 9 of 173 cows (5.2%) and 3 of 102 bulls (2.9%) was excluded because putative paternal alleles were not present in progeny for at least one locus. For 4 of the 9 cows and all 3 bulls, exclusion was based on at least two loci. Mean probability of exclusion was 0.85 for cows and 0.99 for bulls. With an assumed cost of US $5 per genotype, a misidentification rate of 5%, and a discount rate of 0.05, additional profit for the Israeli-Holstein breeding program from genotyping 100 test daughters of each young sire becomes positive within 10 yr and reaches nearly US $2.4 million after 20 yr.

Alleles↗
PubMed1995

Against the laterality index as a measure of cerebral asymmetry.

The laterality index (right - left)/(right + left) has been widely used to measure cerebral asymmetry. However, its validity rests on the assumption that confounding effects of overall head and body size are symmetrical on both sides of the brain. We have found that this assumption may not always be justified. In magnetic resonance imaging data from a group of 43 right-handed normal control and schizophrenic subjects, the laterality index controlled poorly for the asymmetrical confounding effect of height, leading to a spurious (although statistically significant) correlation between height and apparent cerebral asymmetry. Regression modeling is advocated as a more rational and effective way to explore and control size effects confounding cerebral lateralization.

Adult↗