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At least 1,603 records · Page 89Linked to original sources
PubMed2002

Chediak-Higashi syndrome: a clinical and molecular view of a rare lysosomal storage disorder.

Chediak Higashi syndrome (CHS) is a rare, autosomal recessive disorder that affects multiple systems of the body. Patients with CHS exhibit hypopigmentation of the skin, eyes and hair, prolonged bleeding times, easy bruisability, recurrent infections, abnormal NK cell function and peripheral neuropathy. Morbidity results from patients succumbing to frequent bacterial infections or to an "accelerated phase" lymphoproliferation into the major organs of the body. Current treatment for the disorder is bone marrow transplant, which alleviates the immune problems and the accelerated phase, but does not inhibit the development of neurologic disorders that grow increasingly worse with age. There are several animal models of CHS, the beige mouse being the most characterized. Positional cloning and YAC complementation resulted in the identification of the Beige and CHS1/LYST genes. These genes encode a cytosolic protein of 430,000 Da. Sequence analysis identified three conserved regions in the protein: a HEAT repeat motif at the amino-terminus that contains several a helices, a BEACH domain containing the amino acid sequence WIDL, and a WD40 repeat motif, which is described as a protein-protein interaction domain. The presence of the BEACH and WD40 domains defines a family of genes that encode extremely large proteins.

Animals↗
PubMed2006

Assessment of the role of common genetic variation in the transient neonatal diabetes mellitus (TNDM) region in type 2 diabetes: a comparative genomic and tagging single nucleotide polymorphism approach.

Recent evidence supports the strong overlap between genes implicated in monogenic diabetes and susceptibility to type 2 diabetes. Transient neonatal diabetes mellitus (TNDM) is a rare disorder associated with overexpression of genes at a paternally expressed imprinted locus on chromosome 6q24. There are two overlapping genes in this region: the transcription factor zinc finger protein associated with cell cycle control and apoptosis (ZAC also known as PLAGL1) and HYMA1, which encodes an untranslated mRNA. Several type 2 diabetes linkage studies have reported linkage to chromosome 6q22-25. We hypothesized that common genetic variation at this TNDM region influences type 2 diabetes susceptibility. In addition to the coding regions, we used comparative genomic analysis to identify conserved noncoding regions, which were resequenced for single nucleotide polymorphism (SNP) discovery in 47 individuals. Twenty-six SNPs were identified. Fifteen tag SNPs (tSNPs) were successfully genotyped in a large case-control (n = 3,594) and family-based (n = 1,654) study. We did not find any evidence of association or overtransmission of any tSNP to affected offspring or of a parent-of-origin effect. Using a study sufficiently powered to detect odds ratios of <1.2, we conclude that common variation in the TNDM region does not play an important role in the genetic susceptibility to type 2 diabetes.

Alleles↗
PubMed1992

Immunotoxic effects of mercuric compounds on human lymphocytes and monocytes. II. Alterations in cell viability.

The major goal of this investigation was to examine the cytotoxic properties of both HgCl2 and MeHgCl, in terms of their ability to alter human T-cell and monocyte viability. Following treatment with HgCl2 (0-20 micrograms/ml) or MeHgCl (0-2 micrograms/ml), there was minimal reduction in lymphocyte viability at 1-4 hr. However, after exposure to mercury for 24 hr, cell death was apparent. In comparison, monocytes exhibited significant loss of viability during the early exposure periods. MeHgCl was approximately 5-10 times more potent than HgCl2. Other indicators of cell death were also determined. Measurement of the energy charge ratio indicated profound changes in cellular energy conservation. Electron microscopic analysis of cells treated with mercury revealed early nuclear alterations characterized by hyperchromaticity, nuclear fragmentation and condensation of nucleoplasm. In concert with these nuclear changes, there was destruction of cytoplasmic organelles with loss of membrane integrity. Studies of phospholipid synthesis by mercury treated cells confirmed that there were alterations in membrane structure. Thus, there was a decrease in total phosphatide synthesis by treated cells. Moreover, monocyte phospholipid synthesis appeared to be more sensitive to the presence of mercury then lymphocytes. Finally, both forms of mercury caused a rapid and sustained elevation in the intracellular levels of Ca++. These morphological and biochemical changes are consistent with the notion that mercury initiates cytotoxic changes associated with programmed cell death.

Animals↗
PubMed2002

Identification of DC21 as a novel target gene counter-regulated by IL-12 and IL-4.

The Th1 vs. Th2 balance is critical for the maintenance of immune homeostasis. Therefore, the genes that are selectively-regulated by the Th1 and Th2 cytokines are likely to play an important role in the Th1 and Th2 immune responses. In order to search for and identify the novel target genes that are differentially regulated by the Th1/Th2 cytokines, the human PBMC mRNAs differentially expressed upon the stimulation with IL-4 or IL-12, were screened by employing the differential display polymerase chain reaction. Among a number of clones selected, DC21 was identified as a novel target gene that is regulated by IL-4 and IL-12. The DC21 gene expression was up-regulated either by IL-4 or IL-12, yet counterregulated by co-treatment with IL-4 and IL-12. DC21 is a dendritic cell protein with an unknown function. The sequence analysis and conserved-domain search revealed that it has two AU-rich motifs in the 3'UTR, which is a target site for the regulation of mRNA stability by cytokines, and that it belongs to the N-acetyltransferase family. The induction of DC21 by IL-12 peaked around 8-12 h, and lasted until 24 h. LY294002 and SB203580 significantly suppressed the IL-12-induced DC21 gene expression, which implies that PI3K and p38/JNK are involved in the IL-12 signal transduction pathway that leads to the DC21 expression. Furthermore, tissue blot data indicated that DC21 is highly expressed in tissues with specialized-resident macrophages, such as the lung, liver, kidney, and placenta. Together, these data suggest a possible role for DC21 in the differentiation and maturation of dendritic cells regulated by IL-4 and IL-12.

Acetyltransferases↗
PubMed1999

[Causes of unsatisfactory outcome in patients with diabetes mellitus complicated by necrotic inflammation of the foot].

Retrospective analysis of the conservative and surgical treatment results of 222 patients with diabetes mellitus, complicated by necrotic-inflammatory affection of foot, was performed for the 1991-1996 period. In 25.2% of observations the extremity amputation was done on the hip level, 13 (5.8%) of patients died. The unsatisfactory result causes were the reoperation performance on foot in a critical ischemia zone, the decrease of the first operation volume, nonadequate correction of metabolic, haemorheologic disturbances, antibacterial therapy.

Anti-Bacterial Agents↗
PubMed1999

Deficiency of a novel retinoblastoma binding protein 2-homolog is a consistent feature of sporadic human melanoma skin cancer.

Using RNA arbitrarily primed PCR, the authors selected for transcripts with cell cycle-related differential expression in cultured human melanocytes. Among the partial cDNAs cloned, a novel cDNA was identified, which showed 54% identity to the recently cloned cDNA of the retinoblastoma binding protein-2 (RBP2). The 6.5-kB full-length cDNA of this RBP2-related gene, termed RBP2 homolog 1 (RBP2-H1), was obtained from a human teratocarcinoma cDNA library. Two independent libraries from human malignant melanomas were negative. A computerized sequence analysis revealed highly conserved motifs with possible functional meaning: two domains that, in the RBP2 homolog, mediate the binding and interaction with the proteins encoded by the retinoblastoma susceptibility gene, the TATA-binding protein, and the oncoprotein rhombotin 2; in addition, two DNA-binding zinc finger/leukemia-associated protein motifs were detected. Because a functional role in cell-cycle control and transcriptional activation can be envisioned, we investigated the expression of this novel transcript in normal fetal and adult tissues, as well as tissues of benign and malignant melanocytic tumors. By conducting multiple Northern blot, RT-PCR, and in situ hybridization analyses, the authors showed that the corresponding mRNA is expressed in virtually all normal tissues. Accordingly, they found RBP2-H1 expression in microdissected tissue samples from benign melanocytic nevi (n = 10). In contrast, the transcript is significantly down-regulated or even lost in tissue samples from human malignant melanomas (n = 13), melanoma metastases (n = 10), and melanoma cell lines (n = 7). The authors concluded that the loss or down-regulation of RBP2-H1 expression could be a useful molecular marker for a transformed phenotype in the human melanocytic system.

Amino Acid Sequence↗
PubMed2002

Overexpression of murine phosphatidylinositol 4-phosphate 5-kinase type Ibeta disrupts a phosphatidylinositol 4,5 bisphosphate regulated endosomal pathway.

The type I phosphatidylinositol 4-phosphate 5-kinases (PI4P5K) phosphorylate phosphatidylinositol 4-phosphate [PI(4)P] to produce phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. PI(4,5)P2 has been implicated in signal transduction, receptor mediated endocytosis, vesicle trafficking, cytoskeletal structure, and membrane ruffling. However, the specific type I enzymes associated with the production of PI(4,5)P2 for the specific cellular processes have not been rigorously defined. Murine PI4P5K type Ibeta (mPIP5K-Ibeta) was implicated in receptor mediated endocytosis through the isolation of a truncated and inactive form of the enzyme that blocked the ligand-dependent downregulation of the colony-stimulating factor-1 receptor. The present study shows that enforced expression of mPIP5K-Ibeta in 293T cells resulted in the accumulation of large vesicles that were linked to an endosomal pathway. Similar results were obtained after the expression of the PI(4,5)P2-binding pleckstrin homology (PH) domain of phospholipase-Cdelta (PLC-delta). Analysis of the conserved domains of mPIP5K-Ibeta led to the identification of dimerization domains in the N- and C-terminal regions. Enforced expression of the individual dimerization domains interfered with the proper subcellular localization of mPIP5K-Ibeta and the PLC-delta-PH domain and blocked the accumulation of the endocytic vesicles induced by these proteins. In addition to regulating early steps in endocytosis, these results suggest that mPIP5K-Ibeta acts through PI(4,5)P2 to regulate endosomal trafficking and/or fusion.

Cell Line↗
PubMed2003

[Application of multiplex semi-nested polymerase chain reaction in detection of pathogens in cerebrospinal fluid].

OBJECTIVE: To establish a new method of multiplex semi-nested polymerase chain reaction (PCR) to detect pathogens in cerebrospinal fluid (CSF). METHODS: According to the analysis of the conservative and variable regions in bacterial 16S rRNA genes, we designed universal primers for all bacteria and specific primers for most gram-positive and gram-negative bacteria. All primers were added into the same reaction systems successively of a two-step PCR assay to amplify the different bacterial DNA in CSF, and the results were compared with common culture method with sensitivity and the specificity both detected at the same time. RESULTS: Both gram-positive and gram-negative bacteria amplified DNA fragment about 1,032 bp after first-step amplification with universal primers. In the second step, specific fragments of 336 bp and 127 bp were amplified in gram-positive and gram-negative bacteria respectively besides fragments of 1,032 bp; The detection limit for E. coli was 8 cfu/ml. The comparison of 62 CSF samples detected by both multiplex semi-PCR and conventional culture method revealed sensitivity, specificity, positive and negative values of 93.8%, 95.7%, 88.2%, and 97.8% respectively for PCR. CONCLUSION: The result suggested that the multiplex semi-nested PCR we established was sensitive, specific and rapid method for clinical laboratory to detect pathogens in CSF.

Cerebrospinal Fluid↗
PubMed2005

A nuclear targeting determinant for SATB1, a genome organizer in the T cell lineage.

SATB1 is a nuclear protein, which acts as a cell-type specific genome organizer and gene regulator essential for T cell differentiation and activation. Several functional domains of SATB1 have been identified. However, the region required for nuclear localization remains unknown. To delineate this region, we employed sequence analysis to identify phylogenetically diverse members of the SATB1 protein family, and used hidden Markov model (HMM)-based analysis to define conserved regions and motifs in this family. One of the regions conserved in SATB1- and SATB2-like proteins in mammals, fish, frog and bird, is located near the N-terminus of family members. We found that the N-terminus of human SATB1 was essential for the nuclear localization of the protein. Furthermore, fusing residues 20-40 to a cytoplasmic green fluorescence protein (GFP) fused to pyruvate kinase (PK) was sufficient to quantitatively translocate the pyruvate kinase into the nucleus. The nuclear targeting sequence of human SATB1 (residues 20-40) is novel and does not contain clusters of basic residues, typically found in 'classical' nuclear localization signals (NLSs). We investigated the importance of four well-conserved residues (Lys29, Arg32, Glu34, and Asn36) in this nuclear targeting sequences. Remarkably, full-length SATB1 harboring a single point mutation at either Lys29 or Arg32, but not Glu34 or Asn36, did not enter the nucleus. Our results indicate that SATB1 N-terminal residues 20-40 represent a novel determinant of nuclear targeting.

Amino Acid Sequence↗
PubMed1992

Cyclohexadienyl dehydratase from Pseudomonas aeruginosa. Molecular cloning of the gene and characterization of the gene product.

The gene encoding cyclohexadienyl dehydratase (denoted pheC) was cloned from Pseudomonas aeruginosa by functional complementation of a pheA auxotroph of Escherichia coli. The gene was highly expressed in E. coli due to the use of the high-copy number vector pUC18. The P. aeruginosa cyclohexadienyl dehydratase expressed in E. coli was purified to electrophoretic homogeneity. The latter enzyme exhibited identical physical and biochemical properties as those obtained for cyclohexadienyl dehydratase purified from P. aeruginosa. The activity ratios of prephenate dehydratase to arogenate dehydratase remained constant (about 3.3-fold) throughout purification, thus demonstrating a single protein having broad substrate specificity. The cyclohexadienyl dehydratase exhibited Km values of 0.42 mM for prephenate and 0.22 mM for L-arogenate, respectively. The pheC gene was 807 base pairs in length, encoding a protein with a calculated molecular mass of 30,480 daltons. This compares with a molecular mass value of 29.5 kDa determined for the purified enzyme by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Since the native molecular mass determined by gel filtration was 72 kDa, the enzyme probably is a homodimer. Comparison of the deduced amino acid sequence of pheC from P. aeruginosa with those of the prephenate dehydratases of Corynebacterium glutamicum, Bacillus subtilis, E. coli, and Pseudomonas stutzeri by standard pairwise alignments did not establish obvious homology. However, a more detailed analysis revealed a conserved motif (containing a threonine residue known to be essential for catalysis) that was shared by all of the dehydratase proteins.

Amino Acid Sequence↗
PubMedDate not supplied

In vitro quantification of regurgitant jet flow by color Doppler ultrasound and conservation of momentum.

Prosthetic valve regurgitant jets can be imaged with color Doppler ultrasound (CDU), but clinical quantitation remains elusive. An equation based on an integrated conservation of momentum analysis was implemented for CDU quantitation of regurgitation. This was compared with a simple, non-CDU momentum balance analysis recently reported that requires only a pulsed Doppler ultrasound (PDU) reading within the jet and a continuous wave Doppler (CWD) reading of the orifice velocity. For in vitro steady flows, the simple, non-CDU method was accurate only with PDU readings taken 5 cm from the orifice; flows were underestimated when readings 1 and 3 cm from the orifice were used. The CDU method was accurate, even when flows calculated from readings between 0.5 and 6.0 cm from the orifice were averaged together.

Blood Flow Velocity↗
PubMed1991

Nucleotide sequence of cDNA coding for mink proopiomelanocortin (POMC) and its comparative analysis with POMC mRNA primary structures from pituitaries of other animal species and man.

cDNA for proopiomelanocortin (POMC) of mink has been cloned and sequenced. A comparative analysis of the primary structures of mRNAs coding for proopiomelanocortins of eight animal species and man has been performed. The analysis has revealed conserved and variable POMC mRNA regions. High variability of some of the regions is suggested to be due to the peculiarities of their structural organization. A putative mechanism responsible for the mutations in variable regions is proposed. A tree of the evolutionary relations of POMC has been developed.

Amino Acid Sequence↗
PubMed1990

Identification of a human insulinoma cDNA encoding a novel mammalian protein structurally related to the yeast dibasic processing protease Kex2.

We have identified a human insulinoma cDNA (PC2) that encodes a protein homologous to the precursor processing Kex2 endoprotease of yeast by using a polymerase chain reaction to detect and amplify conserved sequences within the catalytic site. The 638-residue amino acid sequence of PC2 begins with a cleavable signal peptide, indicating that it enters the secretory pathway, and contains a 282-residue domain that is homologous to the catalytic modules of both Kex2 and the related bacterial subtilisins. Within this region 49 and 27% of the amino acids are identical to those in the aligned Kex2 and subtilisin BPN' sequences, respectively, and the catalytically essential Asp, His, and Ser residues are all conserved. Northern blot analysis revealed the presence of 2.8- and 5.0-kilobase hybridizing bands in mRNA from the insulinoma. The PC2 protein also shows great similarity to the incomplete NH2-terminal sequence of the human furin gene product, a putative membrane-inserted receptor-like molecule. We propose that PC2 is a member of a family of mammalian Kex2/subtilisin-like proteases that includes members involved in a number of specific proteolytic events within cells, including the processing of prohormones.

Adenoma, Islet Cell↗
PubMed1988

Epidermolytic hereditary palmoplantar keratoderma. Histologic, ultrastructural, protein-chemical, and DNA analyses in two patients.

Two cases of epidermolytic hereditary palmoplantar keratoderma were studied by histologic, ultrastructural, protein-chemical, and genetic methods. Histologically, epidermolytic hyperkeratosis was seen at the spinous and granular layers. Electron microscopy showed the aggregation of tonofibrils and an early appearance of keratohyaline granules as well as vacuolar formation in the epidermal cells. Some of these morphologic abnormalities were detected even in the basal cells. The decrease of 67-kilodalton (kd) keratin and the appearance of 48-kd keratin were noted by using sodium dodecyl sulfate polyacrylamide gel electrophoresis. Genetic analysis of the keratin gene family using 67-kd keratin complementary DNA by Southern blot analysis revealed the conserved gene organization of the 67-kd keratin gene. These findings suggest that undetermined regulatory abnormalities of keratinization, but not the gene structure itself, may be causative factors of this rare disease.

Adult↗
PubMed1989

Regulation of HLA class I transcription in T cells.

Cortical thymocytes express a very low level of HLA class I Ag on their cell surface. As these cells mature to medullary thymocytes and peripheral T cells, HLA class I expression increases to a high level. Leukemic T cell lines arrested at various stages of development were used to examine the regulation of HLA class I expression. Nuclear runoff analysis demonstrated that expression differences in these cell lines were the result of a difference in transcription rates. Electrophoretic mobility shift analysis with the upstream regulatory region of HLA-A2 as a probe for HLA class I-specific DNA binding proteins indicated that DNA binding activity in the cell extracts paralleled the transcriptional activity of the cells. The predominant DNA binding activity in these T cell lines was mapped, by DNase I protection analysis, to a conserved inverted repeat of the MHC class I enhancer. Thus HLA class I expression in these stage-specific T cell lines correlates with the amount of this enhancer binding activity in these cells suggesting that this commonly found DNA binding factor may, in this system, act to regulate HLA class I expression in a very specific manner.

Blotting, Northern↗
PubMed1983

Nucleotide sequences of five maize chloroplast transfer RNA genes and their flanking regions.

Maize chloroplast tRNA genes encoding tRNA3Ser, tRNAPhe, tRNA2Thr, tRNA2Leu, and tRNAmMet, and their flanking regions have been sequenced. All five gene sequences show features commonly found in the few chloroplast tRNA genes sequenced so far; none of them encodes the 3'-terminal CCA triplet and none of them shows abnormal loop or stem lengths as seen in some genes for mammalian mitochondrial tRNAs. The 5'-flanking regions of some of these tRNA genes contain nucleotide stretches strongly homologous to -35 and -10 promoter regions of bacterial genes. Analysis of these conserved regions together with those seen in other plastid genes yields the consensus sequences ATTGANA at "-35" and TAAGAT at "-10." The 3'-flanking regions of some tRNA genes show dyad symmetries followed by a stretch of Thds. These and other regions may be involved in transcription termination or transcript processing.

Base Sequence↗
PubMed1995

[Treatment of severe asymptomatic carotid stenosis].

Severe (reduction of vessel diameter by more than 70%) asymptomatic carotid artery stenosis is associated with a risk of cerebrovascular accident of 2-5% in the year following diagnosis. Results of large, prospective, randomized studies suggest that prophylactic carotid endarterectomy may be beneficial in this situation. However, the elements that must be taken into consideration before deciding to operate on an individual patient are extremely complex. Age and comorbidity (especially cardiovascular conditions) must be considered, as well as perioperative risk and expected medium- and long-term benefits, as compared with optimal conservative treatment. Decision analysis may be of considerable help in such a complex situation by considering objectively and explicitly all these epidemiologic and individual variables. Specifically, the technique makes it possible to simulate threshold probabilities of perioperative complications above which the risks of prophylactic endarterectomy outweigh its benefit, expressed as 5-year survival free of cerebrovascular event. These thresholds are 4%, 3% and 2% for a patient aged 65, 75 and 85 respectively. If 2-year event-free survival is considered, the surgical risk should not exceed 1.5% for a patient aged 65 years or 1% above that age. This type of analysis makes it possible to individualize the guidelines of international panels of experts, but ultimately the decision to operate or not must also consider the psychological profile of the patient and his attitude towards risk ("risk-seeking or risk-averse").

Age Factors↗
PubMed1993

[Does drug-induced litholysis still have a place in treatment of gallstones?].

In past years, laparoscopic cholecystectomy has largely taken the place of conservative therapy. However, analysis of our data shows, that conventional litholytic therapy of cholesterol stones using bile acids: a) achieves a success rate of over 80%, as long as the patients are well selected prior to therapy (stones < 1 cm diameter, stone size < one fourth of gallbladder contraction of more than 50% as compared when fasting, isodensity of stones in CT) b) has a mortality rate of 0% c) has high patient compliance, because typical episodes of biliary colics and general dyspeptic complaints due to stones are reduced. Therefore, combination bile acid therapy for lysis of selected cholesterol gallbladder stones is still justified today. Particularly young women with small, suspended concrements or patients with recurrent cholesterol stones benefit by this treatment. Extracorporeal lithotripsy can be justified today only in combination with bile acid therapy. However, the number of treatable persons with gall stones is quite small (< 20% of all patients with stones), duration of therapy is three years and the recurrence rate 2-5 years after successful lysis is 25-50% (solitary stones recur less often than multiple ones). Considering a prevalence of 20% of persons with gall stones in the European Economic Community, there are 12 million patients potentially eligible for litholysis.

Chenodeoxycholic Acid↗