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E Wolff

Publications and source records attributed to E Wolff.

At least 19 recordsLinked to original sources
PubMed1995

dpa, a member of the MCM family, is required for mitotic DNA replication but not endoreplication in Drosophila.

We have isolated the Drosophila disc proliferation abnormal (dpa) gene, a member of the MCM family of DNA replication factors. Members of this family of proteins are required for DNA replication in yeast. A dpa null mutant dies during pupal stages because imaginal tissues necessary for the formation of the adult fly fail to proliferate normally. Beginning in late embryogenesis BrdU labeling reveals DNA replication defects in mitotically proliferating cells. In contrast, dpa is dispensable for endoreplication, a specialized cell cycle consisting of consecutive rounds of S phases without intervening mitosis. Our studies suggest an essential role for dpa in mitotic DNA replication but not in endoreplication. Thus, dpa is not a general replication factor but may play a specialized regulatory role in DNA replication.

Amino Acid Sequence↗
PubMed1995

The human high mobility group (HMG)-box transcription factor TCF-1: novel isoforms due to alternative splicing and usage of a new exon IXA.

The C-terminal peptide sequences of the human lymphocyte-specific high mobility group (HMG)-box transcription factor TCF-1 are determined by alternative splice mechanisms affecting the exons VIII to X. Here we report, in addition to four splice forms described previously (TCF-1A, B, C, D), the identification of three novel transcripts designated TCF-1E, F, G. Cloning and sequencing of the novel cDNAs revealed (i) joining of the exons VIII and IX to an internal exon X splice acceptor site resulting in a new open reading frame (ORF) of 99 amino acids derived from exon X sequences, (ii) the identification of an additional functional splice acceptor site within exon X, and (iii) a new 81-nucleotide insertion between exon VIII and exon X sequences in a novel transcript form. Genomic cloning and sequence analysis of this transcribed segment of 81 basepairs revealed that it was bordered by canonical splice consensus sites and located in a distance of some 400 bp from both the exons IX and X. It was therefore termed exon IXA. Novel ORFs were generated as a consequence of these alternative splice mechanisms resulting in TCF-1 gene products with significantly different C-terminal peptide sequences, which are prone to selective protein-protein interactions or transactivating functions.

Alternative Splicing↗
PubMed1992

[Thiamin deficiency is common in Israel].

Diseases due to vitamin B1 (thiamin) deficiency are considered to be uncommon in Israel. We present 13 patients admitted during the course of a year who were found to have thiamin deficiency. 5 had classic syndromes such as beri-beri, Wernicke's encephalopathy and cerebellar degeneration. In another 8 the thiamin deficiency was found during workup for less specific neurological abnormalities. Only a minority were alcoholics. Mainly at risk for developing nutritional deficiency were the solitary elderly of low socio-economic status with poor nutrition. Other reasons for thiamin deficiency were drug abuse and hyperemesis gravidarum. Thiamin levels should be determined not only in alcoholics and those with classic B1 deficiency syndromes, but in the routine workup of patients with sensory-motor neuropathy, dementia, gait disorders, cerebellar syndromes and confusional states. It is advised to give vitamins prophylactically to asymptomatic high risk patients.

Adult↗
PubMed1991

prospero is expressed in neuronal precursors and encodes a nuclear protein that is involved in the control of axonal outgrowth in Drosophila.

Neurogenesis in Drosophila begins with the formation of neuronal precursors, which give rise to neurons of individual identity. To find out whether there are genes that are expressed in most or all neuronal precursors and are involved in controlling particular aspects of neuronal differentiation, we used the enhancer-trap method to screen for such "neuronal precursor genes." One gene of this group is prospero. Our mutant analysis indicates that prospero regulates other neuronal precursor genes and is essential for the axonal outgrowth and pathfinding of numerous central and peripheral neurons. prospero encodes a large nuclear protein with multiple homopolymeric amino acid stretches and is expressed in neuronal precursors early during their formation. It is probably generally required for proper neuronal differentiation.

Amino Acid Sequence↗
PubMed1991

Comparison of functional activities between IgG1 and IgM class-switched human monoclonal antibodies reactive with group B streptococci or Escherichia coli K1.

The influence of valence and heavy chain on antibody activity was investigated using transfectoma-derived, class-switched IgG1 and IgM human monoclonal antibodies (MAbs) reactive with the bacterial pathogens Escherichia coli K1 and group B Streptococcus species. IgG-IgM pairs were compared in vitro for antigen binding and opsonic activities and in vivo for protective efficacy in neonatal rats. For the anti-E. coli pair, the IgM MAb was 1000-fold more potent in all assay formats. Importantly, the 50% protection dose (PD50) of the IgM MAb was 10-20 ng/rat, while 100 micrograms of the IgG MAb was only minimally protective. For the group B streptococcal MAbs, the IgM was 100- and 4500-fold more potent in binding and opsonization assays, respectively. However, while 20 micrograms of IgM protected neonatal rats, 100 micrograms of IgG MAb was partly protective. These experiments demonstrate the utility of recombinant DNA technology for creating a panel of antibodies that may aid in selecting potential immunotherapeutic candidates.

Animals↗
PubMed1991

Pharmacokinetic and pharmacodynamic analysis of a human immunoglobulin M monoclonal antibody in neonatal Macaca fascicularis.

We have developed a human MAb that opsonizes group B streptococci, the major cause of gram-positive bacterial sepsis in newborns. It is an IgM class human MAb that possess unique protective activity against experimental infections caused by the predominant group B capsule serotypes III and I. Preliminary preclinical studies with the IgM human MAb were designed to provide initial information useful for predicting its safety and pharmacokinetic properties. Two neonatal Macaca fascicularis monkeys were infused with the human MAb at either 17.8 or 230 mg/kg. Safety was evaluated by visually monitoring postinfusion clinical status and by standard clinical chemistry analyses and quantitative hematology on blood samples collected for 30 d. The serum antibody levels were determined by ELISA and antibody functional activity in serum samples by opsonophagocytic assays. The IgM human MAb appeared safe (normal laboratory values and clinical status) with a half-life of 2.5 d, a period compatible with the 5-d half-life reported for human IgM in adult serum. In addition, the human MAb retained functional opsonic activity for at least 30 d. Human MAb may offer a safe alternative for treating severe bacterial infections.

Animals↗
PubMed1990

Freeze-drying of Streptococcus thermophilus: a comparison between the vacuum and the atmospheric method.

Frozen suspensions of Streptococcus thermophilus were freeze-dried in a vacuum or a fluidized adsorbent bed at atmospheric pressure. Optimum operating conditions for each process were defined. For the duration of processing and survival rate of bacteria, in each case vacuum freeze-drying seemed more satisfactory than atmospheric pressure freeze-drying. The use of reconstituted skimmed milk as a suspension medium provides good protection for S. thermophilus.

Atmospheric Pressure↗
PubMed1989

[Hemodialysis and urea kinetics. An elementary computational program].

An elementary computational program to optimize dialysis in children with chronic renal failure was developed. The program is based on the urea kinetics model. Parameters involved in the efficiency of hemodialysis such as time and clearance, hemofilter performance and body surface area, as well as nutritional needs of the child are considered in the program.

Child↗
PubMed1989

Fine structure DNA mapping studies of the chromosomal region harboring the genetic defect in neurofibromatosis type I.

To better map the location of the von Recklinghausen neurofibromatosis (NF1) gene, we have characterized a somatic cell hybrid designated 7AE-11. This microcell-mediated, chromosome-transfer construct harbors a centromeric segment and a neo-marked segment from the distal long arm of human chromosome 17. We have identified 269 cosmid clones with human sequences from a 7AE-11 library and, using a panel of somatic cell hybrids with a total of six chromosome 17q breakpoints, have mapped 240 of these clones on chromosome 17q. The panel included a hybrid (NF13) carrying a der(22) chromosome that was isolated from an NF1 patient with a balanced translocation, t(17;22) (q11.2;q11.2). Fifty-three of the cosmids map into a region spanning the NF13 breakpoint, as defined by the two closest flanking breakpoints (17q11.2 and 17q11.2-q12). RFLP clones from a subset of these cosmids have been mapped by linkage analysis in normal reference families, to localize the NF1 gene more precisely and to enhance the potential for genetic diagnosis of this disorder. The cosmids in the NF1 region will be an important resource for testing DNA blots of large-fragment restriction-enzyme digests from NF1 patient cell lines, to detect rearrangements in patients' DNA and to identify the 17;22 NF1 translocation breakpoint.

Animals↗
PubMed1988

Localization of the genetic defect in familial adenomatous polyposis within a small region of chromosome 5.

Familial adenomatous polyposis (FAP), a Mendelian disorder that includes familial polyposis coli (FPC) and Gardner syndrome (GS), has an autosomal dominant mode of inheritance. It is characterized by hundreds to thousands of adenomatous polyps that can progress to carcinoma of the colon, suggesting that the gene that harbors the FAP germ-line mutation may play an important role in the somatic genetic pathway to colon cancer. The defect responsible for FAP was recently mapped to the long arm of chromosome 5 by linkage between the FPC phenotype and a locus defined by DNA probe pC11p11 (D5S71), located at 5q21-22. Because an important next step in the paradigm for identification of a disease gene is to obtain a more precise localization, we isolated and mapped by linkage six additional polymorphic DNA markers in the FAP region. Subsequent linkage analysis in six pedigrees, three having the FPC phenotype and three segregating GS, placed the FAP locus very close to a new marker, YN5.48 (D5S81), that is approximately 17 centimorgans distal to C11p11 on the genetic map. The analysis revealed no evidence of genetic heterogeneity between the two phenotypes, a question that had not been clearly resolved by the earlier studies. The new set of markers in the near vicinity of the FAP locus represents a further step toward isolation of the genetic defect and provides the opportunity for preclinical diagnosis of risk status for colon cancer among individuals in families that are segregating adenomatous polyposis.

Adenomatous Polyposis Coli↗