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J Staub

Publications and source records attributed to J Staub.

14 recordsLinked to original sources
PubMed2003

Reproduction and cytogenetic characterization of interspecific hybrids derived from Cucumis hystrix Chakr. x Cucumis sativus L.

Interspecific hybrids between Cucumis hystrix Chakr. (2n = 2 x = 24) and Cucumis sativus L. (2n = 2 x = 14) were produced by means of F(1) (2n = 19) embryo rescue and subsequent chromosome doubling. The hybridity was confirmed by genomic in situ hybridization (GISH) and chromosome analysis. The amphidiploid (2n = 38) was self-pollinated and backcrossed to cucumber resulting in lines with improved crossability to C. sativus. Examination of shape, stainability, and germination rate of pollen grains and yield as a function of mature fruit set per ten pollinated flowers indicated a tendency for increased fertility in BC(1)S(1) progeny when compared to F(1) and amphidiploid offspring. Cytogenetic characterization of F(1) and amphidiploid progeny was performed. Generally normal meioses produced viable pollen grains, and fertilization resulted in partial fertility restoration in amphidiploid progeny. Chromosome anomalies such as "frying-pan trivalent", chromosome lagging and spindle mis-orientation were also observed. In most of the PMCs of the F(1) diploid hybrid progeny, 19 univalents were observed at diakinesis and MI. In the amphidiploid, more than 90% of the configurations at MI consisted of the predicted 19 bivalents and less than 5% contained multivalents [trivalents (2.3%) + quadrivalents (0.3%)], suggesting the presence of preferential pairing, and a distinctive parental genome as well. The chiasmata observed between homoeologous chromosomes further demonstrated the introgression of the C. hystrix genome into that of C. sativus.

Chimera↗
PubMed2001

Genetic analysis of early- versus late-stage ovarian tumors.

In the United States, ovarian cancer is the fourth most common cause of cancer-related deaths among women. The most important prognostic factor for this cancer is tumor stage, or extent of disease at diagnosis. Although women with low-stage tumors have a relatively good prognosis, most women diagnosed with late-stage disease eventually succumb to their cancer. In an attempt to understand early events in ovarian carcinogenesis, and to explore steps in its progression, we have applied multiple molecular genetic techniques to the analysis of 21 early-stage (stage I/II) and 17 advanced-stage (stage III/IV) ovarian tumors. These techniques included expression profiling with cDNA microarrays containing approximately 18,000 expressed sequences, and comparative genomic hybridization to address the chromosomal locations of copy number gains as well as losses. Results from the analysis indicate that early-stage ovarian cancers exhibit profound alterations in gene expression, many of which are similar to those identified in late-stage tumors. However, differences observed at the genomic level suggest differences between the early- and late-stage tumors and provide support for a progression model for ovarian cancer development.

Disease Progression↗
PubMed2001

Loss of expression of a new member of the DNAJ protein family confers resistance to chemotherapeutic agents used in the treatment of ovarian cancer.

Differential display-PCR between ovarian tumor cell lines and short-term cultures of normal ovarian epithelial cell brushings was used to isolate a differentially expressed transcript and its corresponding gene. The gene, which mapped to 13q14.1, has partial homology in the DNAJ domain to a number of proteins with a similar domain and was designated as methylation-controlled J protein (MCJ). MCJ has the highest similarity to a functionally undefined protein from Caenorhabditis elegans. MCJ is expressed as a 1.2-kb transcript in several adult tissues, with testis showing the highest level of expression. Expression of MCJ was absent in three of seven ovarian cancer cell lines. Similarly, expression analysis using semiquantitative reverse transcription-PCR indicated that 12 of 18 primary ovarian tumors examined had either a complete absence or lower levels of expression of this gene. 5-Aza-2'-deoxycytidine treatment of the OV202 cell line induced MCJ expression in a dose-dependent manner, implicating methylation in this induction. Loss of heterozygosity and methylation-specific PCR analysis revealed that the loss of MCJ expression in primary tumors and cell lines was attributable to deletion of one allele and methylation of the other. To assess the potential functional significance of MCJ down-regulation, the sensitivity of parental (MCJ-nonexpressing) and MCJ-transfected OV167 cells to antineoplastic agents was evaluated. MCJ expression was associated with enhanced sensitivity to paclitaxel, topotecan, and cisplatin, suggesting that MCJ loss may play a role in de novo chemoresistance in ovarian carcinoma. These observations raise the possibility that MCJ loss may: (a) have potential prognostic significance in ovarian cancer; and (b) contribute to the malignant phenotype by conferring resistance to the most commonly used chemotherapeutic agents for ovarian cancer.

Amino Acid Sequence↗
PubMed2000

Eye-hand coordination to visual versus remembered targets.

It has been suggested that the basal ganglia preferentially contribute to movements made to remembered targets, whereas the cerebellum preferentially contributes to movements based on visual cues. Thus, it is possible that eye-hand coordination may differ in these two types of movement. To examine this issue we compared the response characteristics of combined eye and hand movements made towards visual versus remembered targets. In addition, the influence of the eye movement on the hand movement was investigated by comparing the effects of visual fixation in each task. Our results demonstrated that hand movement amplitude was greater when the hand movements were produced in isolation versus in combination with an eye movement. This was true regardless of whether the movement was made to a visual or a remembered target. This suggests that the integration of eye position information into the manual motor response occurs at a common neural site for both tasks. By contrast, the timing between saccade and hand onsets and offsets differed in the two conditions. This is consistent with the idea that the timing inherent in eye-hand coordination is the result of separate processing within either the basal ganglia or cerebellar systems. Taken together, the results from this study demonstrate that certain processes underlying eye-hand coordination during movements to visual versus remembered targets share a common neural substrate whereas others function independently.

Adult↗
PubMed1999

A novel region of deletion on chromosome 6q23.3 spanning less than 500 Kb in high grade invasive epithelial ovarian cancer.

Detailed deletion mapping of chromosome 6q sequences in invasive ovarian tumors have implicated several broad regions involving 6q14-16, 6q21-23, 6q25-26, and the telomeric portion in band 6q27 as regions of frequent loss in this malignancy. In order to define regions of loss involved in the development of ovarian cancer, we used 23 polymorphic markers on 6q to examine allelic loss in 25 high-grade, late stage ovarian tumors. Four non-overlapping deletion regions were observed: (1) at 6q21-22.3 (D6S301-D6S292); (2) within a 1 cM region at 23.2-23.3 between markers D6S978-D6S1637 (at D6S311); (3) at 6q26 (between markers D6S411-D6S1277) and (4) at 6q27 with the markers D6S297 and D6S193. The highest region of loss was observed with marker D6S311 (lost in 17 of 19 informative cases, 89%) in 6q23.3, followed by D6S977 and D6S1637 (71 and 55%, respectively). The average fractional allele loss in the high-grade tumors was around 35%. Previous reports have shown 6q27 as the region of most frequent loss in invasive ovarian cancer. However, our results indicate a novel region in 6q23.3 (spanning less than 500 Kb distance between the markers) with the highest loss, implicating this region of chromosome 6q to harbor a putative tumor suppressor gene involved in the development of invasive epithelial ovarian cancer.

Chromosome Fragility↗
PubMed1999

Involvement of H-cadherin (CDH13) on 16q in the region of frequent deletion in ovarian cancer.

Ovarian cancer is one of the leading causes of mortality unique to women. Deletions within chromosome 6q are the most frequent events in high-grade invasive epithelial ovarian cancer (IEOC). While previous reports seem to indicate that there is loss of 16q sequences in IOEC, only a very small number of markers (single marker in two different reports) were used. In order to more precisely define the regions of deletions on 16q, we first analyzed LOH with 13 polymorphic markers on 16q in 10 benign, 3 low-grade and 21 high-grade invasive ovarian cancer samples. There was no loss with any of the markers with the benign ovarian samples and loss of one marker in one of three low-grade tumors. In contrast, 14 of 21 (67%) high-grade invasive ovarian tumors showed loss of one or more markers. Detailed deletion mapping revealed three distinct commonly deleted regions on this chromosomal arm: 10/21 (48%) of high-grade tumors showed loss at 16q23.1-23.2 (D16S518, D16S3049 and D16S3029). The second region of loss at 16q23.3-16q24.1 (D16S3144, D16S504, HSD17B2 and D16S507) was observed in 11/21 (52%) of the tumors. The highest frequency of loss was seen at 16q24.2-16q24.3 (D16S422, D16S402 and D16S520) in 12/21 (57%) of tumors. The genomic map of CDH13 indicates that the marker D16S422 that was lost in 5 of these 12 tumors is part of this gene. Three of these 5 tumors showed very low levels of CDH13 expression. Three tumors with LOH of other markers in this region also showed lower levels of CDH13 expression. Analysis of the methylation status of CDH13 in tumors with low levels of expression with methylation-specific PCR revealed that four of six (67%) tumors had methylation of one of the CDH13 alleles. These results suggest that a combination of hyper-methylation and deletion cause the inactivation of CDH13 in ovarian tumors.

Cadherins↗
PubMed1993

Plastid engineering in land plants: a conservative genome is open to change.

We have developed efficient transformation protocols to modify each of the 500-10,000 plastid genome copies in a tobacco cell. The transforming DNA is introduced on the surface of microscopic tungsten particles by the biolistic process. Selection for transplastomes is by spectinomycin resistance based on expression of aminoglycoside-3"-adenyltransferase from a chimeric aadA gene in the transforming DNA. Manipulations that are now feasible include replacement of endogenous plastid genes with DNA sequences modified in vitro, targeted gene disruption, and insertion of reporter genes into the plastid genome. Alternative methods for plastid genome manipulations may be developed utilizing an extrachromosomal element which was identified during the transformation studies. Introduction of foreign genes under control of plastid gene expression elements results in duplication of endogenous regulatory sequences. A sensitive somatic assay to detect deletions via such direct repeats confirmed that these sequence duplications do not result in significant genome instability. The ability to transform plastids will facilitate the study of plastid gene regulation, and the application of genetic engineering to crop improvement.

Base Sequence↗
PubMed1982

Stress and psychopathology in the aged.

There is a general agreement that the elderly experience a higher proportion of significant life event changes than the younger adult population, and research suggests that life event changes often precede episodes of psychiatric illness. It is also evident, however, that most people over 60 successfully adapt to their changing circumstances without psychiatric disorders. Clearly, the presence of certain physical, psychological, and social mediators may modify the stress response in a predictable fashion. Off-time life events, absence of a confidante, and intrapunitive personality, and a dependence on alcohol, psychotropic, and sedative/hypnotic medications are all examples of mediators that indicate an individual who may be at risk. It is our hope that researchers will continue to identify specific risk factors associated with psychiatric illness in the elderly for use in designing specific prevention and intervention programs for those at risk.

Adaptation, Psychological↗
PubMed1977

Induction of micronuclei in mouse and hamster bone-marrow by chemical carcinogens.

Four carcinogens, dimethylnitrosamine (DMN), acetylaminofluorene (AAF), aflatoxin B1 (AFB1), and 3-methylcholanthrene (3-MC) were tested acutely and chronically in the micronucleus test in both mice and hamsters. In acute studies using mice, all compounds increased the relative frequency of micronuclei when compared to controls. There was a dose response which tended to tail off as bone-marrow suppression was observed. The order of activity appears to be DMN greater than AFB1 greater than or equal to 3-MC greater than AAF. In acute hamster studies, AFB1 was inactive at the highest dose tested (3 mg/kg). In the case of hamsters, all other compounds increased the incidence of micronuclei with DMN greater than 3-MC greater than AAF. Subacute studies with hamsters revealed that 3-MC was active at 1 week but not 8 weeks while DMN was active at both 1 and 8 weeks. AAF was active at 8 and 12 weeks and AFB1 was active at 12 weeks but not 8 weeks. The authors conclude that this test does not appear useful in chronic protocols and probably more reflects carcinogenicity of the test compounds than acute toxicity. Nevertheless, acute studies demonstrate that this test procedure is of value in the characterization of a compound's relative mutagenic potential.

2-Acetylaminofluorene↗
PubMed1976

Inhibition of mouse testicular DNA synthesis by mutagens and carcinogens as a potential sample mammalian assay for mutagenesis.

Since mutagenic substances induce structural changes in DNA, studies were undertaken to determine whether substances would modify DNA replicative activity. DNA synthesis was quantitated 3.5 h after drug administration as uptake into DNA of a 30-min pulse of 10 muCi of [3H] thymidine. Combinations of methylurea (20000 mg/kg) and sodium nitrite (150 mg/kg) administered p.o. resulted in gastric synthesis of nitrosomethylurea and inhibited testicular DNA synthesis by 83%. Combinations of methylurea and sodium nitrite of 1000 and 100 mg/kg respectively inhibited DNA synthesis by 75%. With dimethylamine and sodium nitrite, a combination which results in gastric synthesis of dimethylnitrosamine, inhibitions of 65 and 57% were observed at 2000 mg/kg together with 150 mg/kg and 1000 mg/kg in combination with 100 mg/kg, respectively. In separate experiments, dimethylnitrosamine (50 mg/kg, p.o.) and diethylnitrosamine (100 mg/kg, i.p.) inhibited thymidine uptake by 30 and 89%, respectively. The mutagenic polynucelar hydrocarbon 3-methylcholanthrene (15 mg/kg) inhibited DNA synthesis by 95% and safrole (640 mg/kg), a mutagenic methylenedioxybenzene derivative, inhibited by 60%. Cadmium chloride (10 mg/kg), acetylaminofluorene (160 mg/kg) and dibutylnitrosamine (500 mg/kg) also induced statistically significant effects. Noncarcinogenic analogues of these substances (anthracene, 125 mg/kg; diphenyl-nitrosamine, 500 mg/kg; piperonyl butoxide, 640 mg/kg, and methylurea, 2000 mg/kg in combination with sodium nitrate) were inactive. Highly toxic substances (potassium cyanide, 2.5 mg/kg; 2,4-dinitrophenol, 20 mg/kg; and lead acetate, 150 mg/kg) were also inactive. This index of mutagenicity appears to have considerable sensitivity and therefore may have potential in drug evaluation.

Animals↗
PubMedDate not supplied

Immunogenicity and safety of Haemophilus influenzae type b polysaccharide-Neisseria meningitidis conjugate vaccine in 7.5 micrograms liquid formulation: a comparison of three lots with the 15.0 micrograms lyophilized formulation. Study Group for 7.5 micrograms Liquid PedvaxHIB.

We conducted a multicenter, single-blind, randomized comparisons of the immunogenicity and safety of three manufacturing-scale lots of 7.5 micrograms liquid Haemophilus influenzae type b polysaccharide- Neisseria meningitidis conjugate vaccine (PRP-OMPC) and a single lot of 15.0 micrograms lyophilized PRP OMPC. A total of 908 infants were entered into the study. Each infant received two primary injections intramuscularly 2 months apart beginning at age 2-6 months and a booster injection at 12-15 months. Blood samples for serology were obtained before each injection and 1 month after the second and the booster dose. Immune responses were measured by radioimmunoassay. Approximately 80% of the infants achieved a titer > 1.0 micrograms ml-1 after the second primary dose of all four lots tested: the geometric mean titer (GMT) was ca 3 micrograms ml-1 for each vaccine group. After the booster dose, more than 90% of infants from each vaccine group had a titer > 1.0 microgram ml-1;GMTs ranged from 8 to 10 micrograms ml-1. No serious vaccine-associated adverse reactions were reported. Thus the 7.5 liquid PRP OMPC vaccine was at least as immunogenic and well tolerated as the 15.0 micrograms lyophilized vaccine.

Bacterial Outer Membrane Proteins↗