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At least 1,675 records · Page 93Linked to original sources
PubMed1997

Integrated connective tissue in bioabsorbable barrier material and periodontal regeneration.

The objective of this study was to evaluate the relationship between integrated connective tissue (ICT), that is, the presence of connective tissue into the membrane structure, and the clinical outcome of membrane-supported periodontal surgery. Twenty-six systemically healthy subjects affected by chronic adult periodontitis were enrolled in the study. One tooth site per patient, associated with an angular bony defect and an attachment loss of > 7 mm, was selected to be treated by means of a guided tissue regeneration procedure using a bioabsorbable membrane. Barrier material was surgically removed after 4 weeks for SEM analysis. For each treated site, the difference in clinical attachment loss, probing depth, and gingival recession between the baseline examination and follow-up 6 months after the second surgery was calculated. Gain of attachment was statistically (P < 0.001) greater in sites with no membrane exposure when compared to sites with exposed barrier material (5.5 +/- 1.0 vs. 4.0 +/- 0.6), while further gingival recession was greater (3.0 +/- 0.9 vs. 2.1 +/- 0.5) in sites with clinically exposed membranes. The results of SEM analysis revealed that when connective tissue structures were observed on membrane surfaces, no bacteria could be detected; conversely, areas heavily colonized by bacteria did not show the presence of connective tissue. Regression analysis indicated that integrated connective tissue on the external layer of the barrier material was positively correlated with the amount of attachment gain and negatively with the amount of gingival recession. Bacterial colonization of the membrane was negatively correlated with attachment gain and positively with gingival recession. It was concluded that connective tissue integration is an important biological phenomenon in preventing membrane exposure and bacterial plaque colonization and thus in enhancing the clinical outcome following guided tissue regeneration surgery.

Absorption↗
PubMed1997

Prenatal diagnosis of the fragile X syndrome: loss of mutation owing to a double recombinant or gene conversion event at the FMR1 locus.

The fragile X syndrome, an X linked mental retardation syndrome, is caused by an expanded CGG repeat in the first exon of the FMR1 gene. In patients with an expanded repeat the FMR1 promoter is methylated and, consequently, the gene is silenced and no FMR1 protein (FMRP) is produced, thus leading to the clinical phenotype. Here we describe a prenatal diagnosis performed in a female from a fragile X family carrying a large premutation. In chorionic villus DNA of the male fetus the normal maternal CGG allele and a normal pattern on Southern blot analysis were found in combination with the FRAXAC2 and DXS297 allele of the maternal at risk haplotype. A second chorionic villus sampling was performed giving identical results on DNA analysis and, in addition, expression of FMRP was shown by immunohistochemistry. We concluded that the male fetus was not affected with the fragile X syndrome. Subsequent detailed haplotype analysis showed a complex recombination pattern resembling either gene conversion or a double crossover within a 20 kb genomic region.

Alleles↗
PubMed1993

Laparoscopic appendectomy. A safety and cost analysis.

To assess the feasibility of laparoscopic appendectomy, we reviewed hospital records and charge data for all patients older than age 15 years who underwent appendectomy between November 1990 and July 1992. Fifty-eight patients underwent laparoscopic appendectomy and 206 patients underwent conventional appendectomy. Intraoperative (1.9%) and postoperative (5.8%) complication rates were low. The rate of conversion to conventional appendectomy was 7.7%. Hospital stay and charge analysis was performed on a cohort of 52 patients undergoing laparoscopic appendectomy and 180 patients undergoing conventional appendectomy. Total costs were similar. The most notable difference between the two groups was the operating room supply charge; this negated any cost savings achieved by the reduced length of stay following laparoscopic appendectomy. Laparoscopic appendectomy is a safe alternative to conventional appendectomy; it shortens hospital stay and allows patients to resume normal activity more quickly than conventional appendectomy.

Adolescent↗
PubMed1998

Identification of the oxidation states of the active site cysteine in a recombinant protein tyrosine phosphatase by electrospray mass spectrometry using on-line desalting.

The oxidation state of the cysteine residue at the active site of human protein tyrosine phosphatase (PTP-1B) greatly affects its enzymatic activity. We wished to examine peroxide-treated preparations for modifications of this enzyme with electrospray mass spectrometry in order to determine the locations and oxidation states of the cysteines or other residues involved in the process. Since these reaction products contained large amounts of salts and buffers, they required desalting prior to analysis. Existing on- and off-line methods presented certain difficulties in handling and sample usage. Based on recent experience with direct syringe admission of sample, we developed a procedure as a simple, inexpensive alternative to full high-performance liquid chromatography systems that provides on-line desalting using only a few microL of sample. The method was applied to the analysis of oxidized PTP-1B preparations where conversion of cysteine 215 to both sulfinic and sulfonic acid residues was demonstrated.

Amino Acid Sequence↗
PubMed1995

From rodent glial precursor cell to human glial neoplasia in the oligodendrocyte-type-2 astrocyte lineage.

With only a few exceptions, the precursor cells representing the normal counterparts of human tumours are unknown. The comparative lack of information about the lineages involved in tissue development, and difficulties in growing many human tumors in a manner suitable for cellular biological analysis, together often make it difficult to study the differences between normal and tumor cells and to develop many of the model systems that would be useful in the study of human cancer. By applying techniques previously utilized to study glial progenitor cells, we have isolated a human glioblastoma multiforme (GBM)-derived population that expresses many properties otherwise uniquely expressed by oligodendrocyte-type-2 astrocyte (O-2A) progenitor cells. Hu-O-2A/Gb1 (for Human O-2A lineage Glioblastoma number 1) cells responded to similar mitogens and differentiation modulators as rodent O-2A progenitors, and generated cells with features of precursor cells, oligodendrocytes and astrocytes. Moreover, 1H-NMR analysis of amino acid composition demonstrated a striking conversation of types and quantities of free amino acids between the human tumour cells and the rodent primary cells. Hu-O-2A/Gb1 cells represent the first human glioma-derived population for which unambiguous lineage assignment has been possible, and our results indicate that the human O-2A lineage can contribute to one of the most malignant of glial tumours. In addition, the highly diagnostic 1H-NMR spectrum expressed by Hu-O-2A/Gb1 cells raises the possibility of eventual non-invasive identification of tumors of this lineage.

Animals↗
PubMedDate not supplied

Conversion of high grade lymphoma tumor cell line to intermediate grade with TPA and bryostatin 1 as determined by polypeptide analysis on 2D gel electrophoresis.

A high-resolution two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) was used for total cellular polypeptide mapping of two established lymphoma cell lines; MANCA, a Burkitt's line representing a high grade lymphoma (HGL) and WSU-NHL (nodular histiocytic lymphoma) representing an intermediate grade lymphoma (IGL). Gels were digitized and analysed with an image scanning computer using the Elsie 4 system. Polypeptide mapping revealed striking similarities in 1100 polypeptide spots in both types. However, three polypeptides were unique to HGL (Molecular mass/isoelectric point (Mr/PI): 39/4.4, 35/5.6, 33/4.8), and one to IGL (95/4.7). In order to investigate the kinetics of expression of these polypeptides, the two cell lines were treated with two protein kinase C (PKC) activators, tumour promoting 12-O tetradecanoylphorbol 13-acetate (TPA) and bryostatin 1. 2D-PAGE of the treated cells revealed that the HGL line loses its unique polypeptides and expresses a new one. The new polypeptide has the same Mr and PI as that unique to the untreated IGL (95/4.7). TPA or bryostatin 1 treatment of the IGL line for 72 h induced no significant changes. Our data show a unidirectional change from HGL to IGL, supporting the clinical notion that HGL is less differentiated than IGL. It also shows the similarity in the mode of action of bryostatin 1 and TPA in inducing these polypeptide changes.

Bryostatins↗
PubMed2005

Evidence of reciprocal regulation between the high extracellular calcium and RANKL signal transduction pathways in RAW cell derived osteoclasts.

During bone resorption, osteoclasts are exposed to high Ca2+ concentrations (up to 40 mM). The role of high extracellular Ca2+ in receptor activator of NF-kappaB ligand (RANKL)-mediated osteoclast survival and their functional interrelationship is unclear. In this study, we show that RANKL enhances osteoclast tolerance to high extracellular Ca2+ by protecting the cell from cell death in a dose dependent manner. We have provided evidence that RANKL does this by attenuating high extracellular Ca2+-induced Ca2+ elevations. Moreover, we have found that high extracellular Ca2+-induced cell death was partially inhibited by a caspase-3 inhibitor, suggesting caspase-3-mediated apoptosis is involved. Conversely, using reporter gene assays and Western blot analysis, we have demonstrated that high extracellular Ca2+ desensitizes the RANKL-induced activation of NF-kappaB and c-Jun N-terminal kinase (JNK), and inhibits constitutive and RANKL-stimulated ERK phosphorylation, indicating a negative feed-back mechanism via specific RANKL signaling pathways. Taken together, this study provides evidence for a reciprocal regulation between high extracellular Ca2+ and RANKL signaling in RAW cell derived osteoclasts. Our data imply a cross talk mechanism of extracellular Ca2+ on osteoclast survival through the regulation of RANKL.

Animals↗
PubMed1998

The glycogen phosphorylase-2 promoter binding protein in Dictyostelium is replication protein A.

During Dictyostelium development, glycogen degradation is a crucial event that provides glucose monomers used in the synthesis of the essential structural components for cellular differentiation. The product of the developmentally regulated glycogen phosphorylase-2 gene (gp2) catalyzes the degradation. DNA-binding proteins were found to bind to a regulatory site of the gp2 gene in a stage-dependent pattern. Gel-shift analysis of undifferentiated amoebae cell extract revealed a protein migrating at 0.40 Rf, while 17 hour differentiated cell extract produced a species migrating at 0.32 Rf. Both the 0.32 and 0.40 Rf proteins were purified and found to consist of three subunits of 18, 35 and 62 kDa (for 0.40 Rf) or 81 kDa (for 0.32 Rf). Data base searches identified the protein as the Dictyostelium homologue of replication protein A (DdRPA). Amino acid sequence analysis showed identity between the 62 and 81 kDa subunits. Incubation of cell-free extracts under appropriate conditions at low pH, resulted in conversion of the 81 kDa to the 62 kDa subunit. Northern blot analysis revealed that the levels of expression of the large subunit of DdRPA were constant throughout differentiation and the size of the mRNA was the same at all stages of development. The results raise the possibility that pH induced post-translational modifications of DdRPA are involved in events that halt cell proliferation and induce differentiation in Dictyostelium.

Amino Acid Sequence↗
PubMed1994

Aspects of nonrandom turnover involved in the concerted evolution of intergenic spacers within the ribosomal DNA of Drosophila melanogaster.

Polymerase chain reaction (PCR)-amplified, sequenced, and digitally typed intergenic spacers (IGSs) of the ribosomal (r)DNA in D. melanogaster reveal unexpected features of the mechanisms of turnover involved with the concerted evolution of the gene family. Characterization of the structure of three isolated IGS length variants reveals breakage "hot spots" within the 330-base-pair (bp) subrepeat array found in the spacers. Internal mapping of variant repeats within the 240-bp subrepeat array using a novel digital DNA typing procedure (minisatellite variant repeat [MVR]-PCR) shows an unexpected pattern of clustering of variant repeats. Each 240-bp subrepeat array consists of essentially two halves with the repeats in each half identified by specific mutations. This bipartite structure, observed in a cloned IGS unit, in the majority of genomic DNA of laboratory and wild flies and in PCR-amplified products, has been widely homogenized yet is not predicted by a model of unequal crossing over with randomly placed recombination breakpoints. Furthermore, wild populations contain large numbers of length variants in contrast to uniformly shared length variants in laboratory stocks. High numbers of length variants coupled to the observation of a homogenized bipartite structure of the 240-bp subrepeat array suggest that the unit of turnover and homogenization is smaller than the IGS and might involve gene conversion. The use of PCR for the structural analysis of members of the rDNA gene family coupled to digital DNA typing provides powerful new inroads into the mechanisms of DNA turnover affecting the course of molecular evolution in this family.

Animals↗
PubMed1987

Human red cell acid phosphatase (ACP1): evidence for differences in the primary structure of the two isozymes encoded by the ACP1*B allele.

Molecular properties of the two isozymes expressed by the B allele at the red cell acid phosphatase locus (ACP1) have been studied to distinguish between possible mechanisms for their production. The difference in electric charge exhibited by the native isozymes was retained under denaturing conditions; the unfolded peptide chains renatured without conversion of one form to the other. Chromatographic analysis [thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC)] of tryptic digests showed 12 peptides common to both isozymes but also revealed 5 peptides unique to one isozyme and 3 (possibly 4) peptides unique to the other. These findings argue against both conformational isomerization and simple posttranslational modification as the mechanism of generation of the two isozymes. We suggest that the two isozymes are synthesized as discrete molecular entities.

Acid Phosphatase↗
PubMed1996

A low-cost biotelemetry system for long time monitoring of physiological data.

A biotelemetry system based on digital data processing and transmission is implemented. The transmitter digitizes analog physiological signal, converts into serial form, forms a digital data packet by summing data and synchronization information and transmits the packets via an FM transmitter. The receiver side amplifies and pulse-shapes the received data packet, separates the data and synchronization information, converts serial data into 8-bit parallel form and then into analog signal. A special coding method provides high noise immunity and proper synchronization between transmitter and provides high noise immunity and proper synchronization between transmitter and receiver. The system shows a stable and high performance within a distance of 100 m.

Analog-Digital Conversion↗
PubMed2003

Combined isobutoxycarbonylation and tert-butyldimethylsilylation for the GC/MS-SIM detection of alkylphenols, chlorophenols and bisphenol A in mackerel samples.

The alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) followed by two work-up methods for comparison: isobutoxycarbonyl (isoBOC) derivatization and tert-butyldimethylsilyl (TBDMS) derivatization. Eleven endocrine disrupting chemicals (EDCs) of phenols in biological samples were extracted with acetonitrile and then the acetonitrile layer underwent freezing filtration 60 degrees C for 2 hours. Solid-phase extraction (SPE) was used with XAD-4 and subsequent conversion to isoBOC or TBDMS derivatives for sensitivity analysis with the GC/MS-SIM mode. For isoBOC derivatization and TBDMS derivatization the recoveries were 92.3 approximately 150.6% and 93.8-108.3%, the method detection limits (MDLs) of bisphenol A for SIM were 0.062 microg/kg and 0.010 microg/kg, and the SIM responses were linear with the correlation coefficient varying by 0.9755-0.9981 and 0.9908-0.9996, respectively. When these methods were applied to mackerel samples, the concentrations of the 11 phenol EDCs were below the MDL.

Aldehydes↗
PubMed2002

Pattern of segmental recombination in the distal inversion of mouse t haplotypes.

To examine genetic exchange between t haplotypes and their wild-type homologs, four previously identified mouse Chromosome (Chr) 17 variants termed mosaic haplotypes were analyzed in detail. Three of these haplotypes-one from a Mus musculus population in Bulgaria, one from a Mus domesticus population in Chile, and one from a M. domesticus population in Germany-display properties indicative of the t complex. All four haplotypes are exceptional because they are characterized by the presence of a few wild-type DNA markers in the distal inversion [In(17)4] of a t haplotype chromosome: thus, they are classified as mosaic t haplotypes. The mosaic pattern for each haplotype is distinct, however. We compared the mosaic haplotypes with each other, and with several well-characterized laboratory t haplotypes, by analyzing several DNA markers in the In(17)4 region of the t complex, where all of the mosaicism occurs. We used a combination of high-resolution restriction mapping, DNA sequencing, and analysis of new DNA markers to classify the haplotypes. This analysis shows that segmental exchange, either by gene conversion or double crossing-over, has occurred at molecular markers in the vicinity of a gene, Dnahc8, that is a candidate for the t complex distorter locus Tcd2. While it is unclear whether segmental exchanges have included the Tcd2 gene, it is apparent that several independent recombination events have occurred in In(17)4 during the recent evolution of t haplotypes.

Animals↗
PubMed2006

Seed-specific expression of sesame microsomal oleic acid desaturase is controlled by combinatorial properties between negative cis-regulatory elements in the SeFAD2 promoter and enhancers in the 5'-UTR intron.

The regulation of genes involved in primary lipid metabolism in plants is much less well understood than that in many other pathways in plant biology. In the investigation reported here, we have characterized transcriptional regulatory mechanisms controlling seed-specific FAD2 expression in sesame (Sesamum indicum). FAD2 codes for extra-plastidial FAD2 desaturase, which catalyzes the conversion of oleic acid to linoleic acid. Promoter analysis of the sesame FAD2 gene (SeFAD2) using the beta-glucuronidase (GUS) reporter system demonstrated that the - 660 to - 180 promoter region functions as a negative cis-element in the seed-specific expression of the SeFAD2 gene. Sesame and Arabidopsis FAD2 genes harbor one large intron within their 5'-untranslated region. These introns conferred up to 100-fold enhancement of GUS expression in transgenic Arabidopsis tissues as compared with intron-less controls. Prerequisite cis-elements for the SeFAD2 intron-mediated enhancement of gene expression and the promoter-like activity of SeFAD2 intron were identified. SeFAD2 transcripts were induced by abscisic acid (ABA) in developing sesame seeds, and the - 660 to - 548 and - 179 to - 53 regions in the SeFAD2 promoter were implicated in ABA-responsive signaling. Theses observations indicate that an intron-mediated regulatory mechanism is involved in controlling not only the seed-specific expression of the SeFAD2 gene but also the expression of plant FAD2 genes, which are essential for the synthesis of polyunsaturated fatty acids.

5' Untranslated Regions↗
PubMed1987

Voice restoration after total laryngopharyngectomy and cervical esophagectomy using the duckbill prosthesis.

We have presented a series of 10 patients who were successfully rehabilitated using the tracheoesophageal puncture technique for voice restoration. These patients underwent total laryngopharyngectomy or laryngopharyngoesophagectomy and reconstruction with visceral transposition (five patients), myocutaneous flaps (four patients), and skin graft and cervical flaps (one patient). All patients were able to produce adequate voice and carry on a conversation. Clinical evaluation of voice quality and acoustic analysis of voice samples indicate that the voice obtained in these patients was intelligible, and had adequate intensity, low pitch, and limited pitch variation. There were no complications related to the voice restoration procedure. It appears from our data and the limited experience reported in the literature that the tracheoesophageal prosthesis can be used successfully and safely for the speech rehabilitation of patients who undergo total laryngopharyngectomy, cervical esophagectomy, or both, regardless of the reconstructive method used.

Aged↗
PubMed1987

Development of carboxypeptidase K (creatine kinase conversion factor) in man.

The developmental appearance of carboxypeptidase K in human plasma was determined by quantifying the creatine kinase (CK) isoforms present and by measuring the conversion of tetrathionate-blocked CK in vitro. Analysis of plasmas from second and third trimester fetuses, newborns and adults showed that isoforms were absent from second trimester fetuses, were present in similar amounts in third trimester fetuses and newborns, and had increased to about twice this amount in adults. Carboxypeptidase K activity was correspondingly absent from second trimester fetuses but present in the other three groups in statistically indistinguishable amounts. Carboxypeptidase N was present in all groups although activity was low in second trimester fetuses. Addition of cobalt ions activated both carboxypeptidases K and N in all samples and unmasked carboxypeptidase K in second trimester samples.

Adult↗
PubMed1979

EEG data acquisition and preprocessing by microcomputer satellite system.

Recent development in computer technology allows already medium scale EEG data processing to be performed within the clinical neurophysiology department, if a fast minicomputer with adequate mass storage and graphical output facilities is used. Data acquisition, however, should be delegated to a microcomputer which also should take over as much preprocessing as possible. A system is presented, where one or several microcomputer-based satellite units perform analog-digital conversion, Fourier transformation (FFT), calculation of power spectra and crossproducts, as well as event related averaging or other preprocessing procedures. The units are connected to a fast central minicomputer, where a supervisor program loads the microprocessors with their programs, supervises their activity, receives preprocessed data and activates appropriate postprocessing programs to produce the final results.

Analog-Digital Conversion↗