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At least 523 records · Page 29Linked to original sources
PubMed1999

Genetic dissection of X-linked interspecific hybrid placental dysplasia in congenic mouse strains.

Interspecific hybridization in the genus Mus results in male sterility and X-linked placental dysplasia. We have generated several congenic laboratory mouse lines (Mus musculus) in which different parts of the maternal X chromosome were derived from M. spretus. A strict positive correlation between placental weight and length of the M. spretus-derived part of the X chromosome was shown. Detailed analysis was carried out with one congenic strain that retained a M. spretus interval between 12.0 and 30.74 cM. This strain consistently produced hyperplastic placentas that exhibited an average weight increase of 180% over the weight of control placentas. In derived subcongenic strains, however, increased placental weight could no longer be observed. Morphometric analysis of these placentas revealed persistence of abnormal morphology. Fully developed placental hyperplasia could be reconstituted by recombination of proximal and central M. spretus intervals with an intervening M. musculus region. These results may suggest that placental dysplasia of interspecific mouse hybrids is caused by multiple loci clustered on the X chromosome that act synergistically. Alternatively, it is possible that changes in chromatin structure in interspecific hybrids that influence gene expression are dependent on the length of the alien chromosome.

Animals↗
PubMed1988

Oocyte and somatic 5S ribosomal RNA and 5S RNA encoding genes in Xenopus tropicalis.

We have investigated the structure of oocyte and somatic 5S ribosomal RNA and of 5S RNA encoding genes in Xenopus tropicalis. The sequences of the two 5S RNA families differ in four positions, but only one of these substitutions, a C to U transition in position 79 within the internal control region of the corresponding 5S RNA encoding genes, is a distinguishing characteristic of all Xenopus somatic and oocyte 5S RNAs characterized to date, including those from Xenopus laevis and Xenopus borealis. 5S RNA genes in Xenopus tropicalis are organized in clusters of multiple repeats of a 264 base pair unit; the structural and functional organization of the Xenopus tropicalis oocyte 5S gene is similar to the somatic but distinct from the oocyte 5S DNA in Xenopus laevis and Xenopus borealis. A comparative sequence analysis reveals the presence of a strictly conserved pentamer motif AAAGT in the 5'-flanking region of Xenopus 5S genes which we demonstrate in a separate communication to serve as a binding signal for an upstream stimulatory factor.

Animals↗
PubMed1997

Transcription and polyadenylation in a short human intergenic region.

The poly(A) signal of the human Lamin B2 gene was previously shown to lie 600 bp upstream of the cap site of a gene of unknown function (ppv 1). However, using RNase protection analysis, we show that ppv 1 has two clusters of multiple initiation sites, so that the 5"cap site lies only approximately 280 nt downstream of the Lamin B2 poly(A) signal. We analysed nascent transcription across this unusually short intergenic region using nuclear run-on analysis of both the endogenous locus and of transiently transfected hybrid constructs. Surprisingly, transcription of the Lamin B2 gene does not appear to terminate prior to any of the mapped ppv 1 start sites, although pausing of the elongating polymerase complexes is observed downstream of the Lamin B2 poly(A) signal. We suggest that this pausing may be sufficient to protect the downstream gene from transcriptional interference. Finally, we have also investigated the sequences required for efficient recognition of the Lamin B2 poly(A) signal. We show that sequences upstream of the AAUAAA element are required for full activity, which is an unusual feature of mammalian poly(A) signals.

Base Sequence↗
PubMed2006

Spatial organization of transcription by RNA polymerase III.

RNA polymerase III (pol III) transcribes many essential, small, noncoding RNAs, including the 5S rRNAs and tRNAs. While most pol III-transcribed genes are found scattered throughout the linear chromosome maps or in multiple linear clusters, there is increasing evidence that many of these genes prefer to be spatially clustered, often at or near the nucleolus. This association could create an environment that fosters the coregulation of transcription by pol III with transcription of the large ribosomal RNA repeats by RNA polymerase I (pol I) within the nucleolus. Given the high number of pol III-transcribed genes in all eukaryotic genomes, the spatial organization of these genes is likely to affect a large portion of the other genes in a genome. In this Survey and Summary we analyze the reports regarding the spatial organization of pol III genes and address the potential influence of this organization on transcriptional regulation.

Animals↗
PubMed2004

Analysis of DNA damage generated by high-energy particles.

Ionizing radiation generates isolated and localized multiple (i.e., clustered) lesions in DNA, and the latter is believed to be primarily responsible for deleterious biological consequences such as cell killing and mutations. In the present study, we irradiated plasmid and lambda DNA by ionizing radiations with different linear energy transfer (LET) values, and compared the yields of isolated and clustered DNA lesions.

Carbon↗
PubMed2007

Clustering of double strand break-containing chromosome domains is not inhibited by inactivation of major repair proteins.

For efficient repair of DNA double strand breaks (DSBs) cells rely on a process that involves the Mre11/Rad50/Nbs1 complex, which may help to protect non-repaired DNA ends from separating until they can be rejoined by DNA repair proteins. It has been observed that as a secondary effect, this process can lead to unintended clustering of multiple, initially separate, DSB-containing chromosome domains. This work demonstrates that neither inactivation of the major repair proteins XRCC3 and the DNA-dependent protein kinase (DNA-PK) nor inhibition of DNA-PK by vanillin influences the aggregation of DSB-containing chromosome domains.

Animals↗
PubMedDate not supplied

Segmental colonic involvement of plexiform neurofibroma in neurofibromatosis type 1.

In a 36-year-old man with neurofibromatosis type 1, rare colonic involvement of plexiform neurofibroma is presented. The diagnosis was confirmed by operation. Radiologic findings consisted of marked concentric thickening of the colonic wall with variable attenuation, namely, a "multilayer appearance," as well as clusters of multiple soft tissue nodules in the mesentery.

Adult↗
PubMed2002

Efficacy, immunogenicity and safety of heptavalent pneumococcal conjugate vaccine in low birth weight and preterm infants.

OBJECTIVE: To determine the efficacy, immunogenicity and safety of the heptavalent CRM197 pneumococcal conjugate vaccine (PCV) in low birth weight (LBW) and preterm (PT) infants against invasive pneumococcal disease caused by vaccine types. METHODS: In a randomized double blind trial of 37,868 infants given either PCV or meningococcal type C conjugate vaccine (MCV), 1756 infants <750 g <2500 g (LBW) and 4340 infants from 32 to <38 weeks old (PT) were identified. Risk of invasive pneumococcal disease in LBW and PT infants was compared with risk in normal birth weight (NBW) and full term (FT) infants. Local and systemic events observed within 48 h of recent vaccine were assessed by telephone interviews and similar comparisons made. Premature infant Emergency Department visits and hospitalization were also identified and compared with FT and NBW infants. RESULTS: Initiation of immunization and intervals between doses were similar for all groups. The risk ratio for invasive pneumococcal diseases for LBW infants compared with NBW infants was 2.6 (P = 0.03), and for PT compared with FT infants the risk ratio was 1.6 (P = 0.06). Vaccine efficacy for both groups was 100%. PCV was as immunogenic in LBW and PT as in NBW and FT infants. Fever and local events after PCV vaccination were similar when adjusted for clustering among multiple doses per child. When stratified for individual doses there was more redness and swelling for LBW infants and more swelling for PT infants after Dose 3. Isolated local and systemic reactions were more commonly seen with PCV than with MCV, a pattern similar to that in NBW and FT infants. Hospitalization rates were similar for PCV and MCV recipients. CONCLUSION: These data support the use of PCV in LBW infants and PT infants.

Disease Susceptibility↗
PubMed1994

Noncardiac Chest Pain: A Focus on Psychogenic Causes.

Patients presenting with noncardiac chest pain of psychogenic origin are one of the more challenging clinical dilemmas to primary care medicine. Key aspects to recognition of these patients are predominance of autonomic complaints, multiple presentations, clustering of physical complaints and a repeated history of negative cardiac pathology, a clinical profile of anxiety or panic disorder. Therapy can be achieved by the use of benzodiazepines. Psychiatric consultation is to be sought following successful symptom abatement from a parenteral benzodiazepine challenge in the emergency department on successive occasions.

Journal Article↗
PubMed1989

Structure of the human lysosomal acid phosphatase gene.

We have isolated a 12-kb genomic clone, which encodes human lysosomal acid phosphatase (LAP), a lysosomal membrane glycoprotein. The human LAP gene has a size of about 9 kb and contains 11 exons (83-947 bp in size). The signal sequence and the first eight amino acids of the LAP protein are encoded by exon 1, the remaining luminal domain by exons 2-10 and the transmembrane and cytoplasmic domains, as well as the 3'-untranslated region, by exon 11. The sequence of the LAP gene confirmed the sequence deduced from the cDNA clone except for nucleotide 1917 in the 3'-untranslated region, where T is changed to C. The 5'-flanking sequence shows promoter activity, as analysed by coupling to bacterial chloramphenicol acetyltransferase. S1-nuclease-protection and primer-extension analysis demonstrate transcription initiation at multiple sites clustering within 23 bp upstream of the translation-initiation codon. Sequences characteristic for promoter regions like TATA-box and CAAT-box sequences could not be identified at typical positions. The absence of these sequences, the high GC content (63.5%), two GC boxes and a region complying with the properties of a CpG island, indicate that LAP is a housekeeping gene.

Acid Phosphatase↗
PubMed2005

Isolation of the choanocyte in the fresh water sponge, Ephydatia fluviatilis and its lineage marker, Ef annexin.

In order to investigate the cellular system of the freshwater sponge, Ephydatia fluviatilis, we isolated a molecular marker for the most prominent cell type, the choanocyte. After feeding sponge with fluorescent beads, fluorescent-labeled choanocytes were collected by fluorescence activated cell sorting (FACS). By protein profiling choanocyte and archeocyte (stem cell)-rich fractions, proteins characteristic of choanocyte were identified. The partial amino-acid sequence of one of the proteins characteristic of choanocyte matches the deduced amino-acid sequence of sponge expression tag (EST) clones and mouse annexin VII. These EST clones overlap and encode a protein, designated Ef annexin, which includes four annexin domains. Whole mount in situ hybridization shows Ef annexin expression in chamber-forming choanocytes in 7-day-old sponge, leading us to conclude that Ef annexin can be used as a choanocyte marker. In the early development stage, Ef annexin expression can be detected in both large single cells, characteristic of archeocytes, and cells forming 2-, 4- and multiple-cell clusters. These results indicate that Ef annexin is initially expressed in the choanocyte-committed archeocyte which then undergoes several mitotic cell divisions to form a choanocyte chamber. This suggests that the single choanocyte chamber essentially originates from a single archeocyte.

Amino Acid Sequence↗
PubMed2004

Improving outcomes in the post-myocardial infarction setting.

Heart disease is the leading cause of death in the United States, with African-American men having the highest rate of cardiovascular mortality in the US population. Although the clustering of multiple cardiovascular risk factors is particularly apparent in this group, a key reason for the higher rate of cardiovascular mortality among African-American men compared with other ethnic groups may be related to underdiagnosis and undertreatment. Studies have shown that minority persons with myocardial infarction are less likely than non-minorities to be diagnosed, to receive appropriate drug therapy, or to undergo bypass surgery. However, there are no data that suggest established treatments and secondary prevention strategies are less effective in African Americans. Appropriate therapy for secondary prevention--including thrombolysis, antiplatelet strategies, angiotensin-converting enzyme inhibition, beta blockade, and lipid-lowering therapies--results in significant reductions in mortality for all patients.

Black or African American↗
PubMed1993

Criteria for anatomical compatibility of the total artificial heart: computerized three-dimensional modeling of the cardiovascular anatomy.

A quantitative study of cardiovascular anatomy was performed by obtaining three-dimensional reconstructions from regular computed tomography scan images in 15 patients, all candidates for heart transplantation. Volumetric estimates of the cardiovascular structures were obtained from these three-dimensional reconstructions using data directly related to total artificial heart (TAH) implantations. By using computerized three-dimensional modeling of these structures, reproducible measurements of the parameters defining the shape and the anatomical connections of the intrathoracic space available for TAH implantation could be derived. The results are intended to be used for both technical and clinical applications such as computer-assisted drawing of the pericardial cavity and the anatomical connections (useful for improving the design of TAH) and combined statistical calculations (multiple regressions, cluster algorithm) of the measurement results, which will then enable the best selection to be made among two or three TAH models for each patient.

Aortography↗
PubMed1997

Precursors of cardiovascular risk in young adults from a biracial (black-white) population: the Bogalusa Heart Study.

Pediatric epidemiology programs have established that the major adult cardiovascular (C-V) diseases, coronary-artery disease, and essential hypertension, begin in childhood. Cardiovascular risk factors change during periods of growth and development, and there are distinct ethnic (black-white) and male-female differences that relate to adult heart disease. These risk factors have been shown to "track" over a 15-year period and are predictive of adult levels. Secular trends show increasing adiposity in the general population of children; an overall weight gain of 2 kg occurred during the decade from the 1970s to the 1980s, and approximately 5 kg during the decade from the 1980s to the 1990s. In all likelihood, increasing obesity is related to a more sedentary lifestyle. Cardiovascular risk factors also tend to cluster, for example, obesity correlates with higher blood pressure and with adverse serum lipoprotein changes. Further, a central distribution of obesity clusters with multiple risk factors in the insulin-resistant syndrome. Importantly, antemortem risk factors relate to actual C-V lesions found at autopsy. Lesions of a progressive nature occur in coronary vessels, which can ultimately result in clinical coronary heart disease. The development of lesions lag in young women at an equivalent age and with similar levels of risk factors. In addition, ethnic differences are noted in the development of C-V changes related to atherosclerosis and hypertension. The demonstration of C-V disease in early life gives credibility to risk-factor examination of children and the need for beginning of prevention in early life.

Adolescent↗
PubMed1997

[Human fascioliasis: comparison of a fasciolicidal effect of bithionol and praziquantel].

There is no consensus about the optimal treatment for fascioliasis. Here we report 5 cases of fascioliasis and 12 cases of fascioliasis reviewed from the literature, and discuss the clinical characteristics and treatment of this parasitic disease. The diagnosis was made in 88% of all patients by the serological test and eggs in the feces were negative in all patients. The characteristic CT findings of all patients in our series were cluster of multiple abscess-like lesions in the liver. Eosinophilia was present in all patients. Bithionol was effective in all of the 13 patients and praziquantel was effective in 4 of 8 patients. Three of 4 patients, in whom praziquantel was not effective, were treated with bithionol successfully. No severe side effects were noticed in all patients. Bithionol seems to be more effective against fasciola sp. than praziquantel. Bithionol is proposed as the drug of choice for the treatment of human fascioliasis.

Aged↗
PubMed1995

Intracellular location of Bartonella henselae cocultivated with Vero cells and used for an indirect fluorescent-antibody test.

Bartonella henselae, the major causative agent of cat scratch disease, was cocultivated with Vero cells on chamber slides and visualized by indirect immunofluorescence by using a patient serum containing specific antibodies. Confocal microscopy localized the granular B. henselae-specific fluorescence mainly around the nuclei of Vero cells. By transmission electron microscopy, these granules were identified as clusters of multiple intracellular organisms. Fixed slides with the monolayers of Vero cells with intracellular B. henselae were used for an indirect fluorescent-antibody test to investigate the seroprevalence of specific immunoglobulin G in 100 serum samples from blood donors. Seventy-four serum samples were negative; 19, 3, and 4 were positive at dilutions of 1:64, 1:128, and 1:256, respectively. In our population, a serum titer of 1:256 or greater should stimulate further investigations. Moreover, elucidation of the mechanism by which B. henselae enters the cells may help to understand the pathogenesis of cat scratch disease.

Animals↗
PubMed1989

Expression of type 1 fimbriae and mannose-sensitive hemagglutinin by recombinant plasmids.

Deletions within the cloned genes (fimA) encoding the type 1 major fimbrial subunits of two isolates of Klebsiella pneumoniae resulted in a nonfimbriate but hemagglutinating phenotype after transformation of Escherichia coli HB101 or ORN103. Phenotypic expression of type 1 fimbriae could be restored by transformation with plasmids containing the fimA genes of the fimbrial gene clusters from different strains. The surface fimbriae expressed were serologically identical to those of the polymerized product of the introduced fimA gene. The fimA gene products of Salmonella typhimurium and Serratia marcescens could utilize the accessory fimbrial genes of K. pneumoniae to produce surface-associated, hemagglutinating fimbriae. The relatedness of the type 1 fimbrial gene clusters from multiple isolates of members of the family Enterobacteriaceae was examined by DNA hybridization techniques. These analyses demonstrated little nucleotide sequence agreement among distinct genera of the enteric bacteria.

Bacterial Adhesion↗