PubMed Health⌕ Search

Biomedical subjects

M Zimmer

Publications and source records attributed to M Zimmer.

At least 19 recordsLinked to original sources
PubMed1995

Cloning and structure of the gene encoding the human N-methyl-D-aspartate receptor (NMDAR1).

The complete gene encoding the human N-methyl-D-aspartate receptor subunit NR1 (NMDAR1) has been isolated on a single cosmid clone. The gene is composed of 21 exons distributed over a total length of about 31 kb. More than 24 kb were sequenced. Exons 4, 20 and 21 are identical in their amino-acid sequence to those exons that are subject to alternative splicing in rat, indicating that all eight NMDAR1 isoforms found in rat will also be expressed in the human brain. Computer analysis of the pre-mRNA sequence revealed no secondary structures stable enough to explain alternative splicing. We suggest that cell-specific factors control expression of different isoforms. The promoter region contains two perfect copies of the recognition sequence for the Drosophila even-skipped protein, indicating that the developmentally regulated expression of NMDAR1 is controlled by a homeobox protein. The complete cosmid clone covering NMDAR1 was mapped to chromosome 9q34.3-qter by fluorescent in situ hybridization (FISH). The telomeric location is supported by an imperfect (CA)n repeat homologous to a subtelomeric repeat on chromosome 16p.

Alternative Splicing↗
PubMed1994

The human Met-ase gene (GZMM): structure, sequence, and close physical linkage to the serine protease gene cluster on 19p13.3.

Cosmid clones containing the genes for the human and murine natural killer cell serine protease Met-ase (gene symbol GZMM; granzyme M) were identified by screening human and murine cosmid libraries with rat Met-ase (RNK-Met-1) cDNA. The human gene has a size of 7.5 kb and an exon-intron structure identical to that of serine protease genes located on human chromosomes 5q11-q12, 14q11.2, and 19p13.3 that are expressed by lymphocytes, mast cells, or myelomonocyte precursors. Using cosmid DNA as a probe for fluorescence in situ hybridization, we identified the chromosomal position of human Met-ase as 19p13.3. Interphase studies with two differentially labeled probes for Met-ase and the azurocidin (AZU1), proteinase 3 (PRTN3), and neutrophil elastase (ELA2) gene cluster revealed that the distance of Met-ase from this gene cluster is in the range of 200 to 500 kb. Using differentially labeled mouse cosmid probes, we also mapped the murine gene for Met-ase to chromosomal band 10C, close to the gene for lamin B2. Thus, the Met-ase, AZU1, PRTN3, and ELA2 genes fall into an established region of homology between mouse chromosomal band 10C and human 19p13.3.

Amino Acid Sequence↗
PubMed1994

[Evaluation of the effect of oxytocin use for labor induction on frequency of occurrence and severity of neonatal jaundice].

Authors conducted analysis of effect of method used (which consisted of use of oxytocin, vit B, oestradiol) for labour induction on frequency of occurrence and severity of neonatal jaundice on 3rd day of neonatal life. Analysed material consisted of 1154 deliveries between the years 1990 to 1992 in IInd Department of Obstetrics AM Wrocław. Only completely physiological pregnancies qualified for analysis. The above mentioned sum of analysed deliveries was divided into 2 groups. Ist group consisted of 801 normal deliveries without any oxytocin use 2nd group consisted of 353 normal deliveries during which i.v. oxytocin drip was used either for induction of labour or to intensify uterine contraction during labour. Evaluation of the above data do not show significant increase in cases with hyperbilirubinemia in group with labour induction (7%) in comparison with deliveries without oxytocin use (5%). Moreover eliminating from the analysis cases of jaundice with normal bilirubin level (12 mg%), I degree jaundice, the actual count of cases of hyperbilirubinemia in group without oxytocin use in 26 (3.24%) and in group with oxytocin use is 13 (3.67%) cases (Tab. IV) which is not a significant difference and does not permit us to conclude that oxytocin use for labour induction is responsible for increased frequency of neonatal hyperbilirubinemia.

Female↗
PubMed1992

Three human elastase-like genes coordinately expressed in the myelomonocyte lineage are organized as a single genetic locus on 19pter.

The human neutrophil and monocyte-derived serine protease homologues neutrophil elastase (NE), proteinase 3 (PR3), and azurocidin (AZU) are involved in a variety of immune defense reactions. NE and PR3 assist in the destruction of phagocytosed microorganisms, cleave the important connective-tissue protein elastin, and generate chemotactic activities by forming alpha 1-proteinase inhibitor complexes and elastin peptides. AZU is cytotoxic to certain microorganisms and chemotactic for monocytes. All three proteins are produced and packaged into azurophil granules in large quantities during neutrophil differentiation. We have isolated several cosmid clones each of which contains the functional genes for AZU, PR3, and NE in this order. The PR3 gene is separated by 8 kilobases from the 3' end of the AZU gene and by 3 kilobases from the 5' end of the NE gene. We report a physical map of the gene cluster, its location on chromosome 19pter, and the exon-intron organization of the AZU and PR3 genes. Our fluorescence in situ hybridization studies disprove the previous chromosomal assignment of the human NE gene to 11q14. The five exons of AZU and PR3 are organized like those of NE and other granule-associated serine proteases of hematopoietic cells. NE, PR3, and AZU are coordinately downregulated in the premonocytic cell line U937 during induced terminal differentiation. The cluster-like physical organization of these genes and concerted regulation during hematopoietic differentiation suggests that they are located in a developmentally activated chromatin domain promoting high-level, cell-specific expression in the monocyte-myelocyte lineage.

Amino Acid Sequence↗
PubMed1992

Bone-cement removal with the excimer laser in revision arthroplasty.

The excimer laser was thought to be an appropriate tool for the removal of bone cement without damaging the bone. However, due to its low ablation rate, its clinical use in total hip revision arthroplasty proved to be impossible. This experimental study was designed to evaluate the maximal ablation rate by adjusting the laser's parameters. Energy density, frequency, pulse duration, radiation area, quantity of pulses, and environmental conditions were varied in the experimental setup. Even with the best set of parameters the excimer laser was about ten times slower than, e.g., the carbon dioxide laser. The removal of 10 g bone cement takes about 1 h. Thus, complete cement removal by means of the excimer laser alone is not possible. However, selective application of the excimer laser in combination with other techniques could be discussed.

Arthroplasty↗
PubMed1992

Moderate heat treatment of bone allografts. Experimental results of osteointegration.

The use of bone allografts is often essential in orthopedic surgery. Strict donor screening, including HIV testing 3 months postoperatively, is mandatory before a transplant may be used. Yet these measures do not definitely rule out the possibility of HIV transmission, as there is a window period before infection is revealed by blood testing. Accordingly, there is a need for virus inactivation methods that can be used on bone allografts. As radiation treatment and chemical methods have a number of disadvantages, we chose a moderate heat treatment of 65 degrees C for a series of animal experiments. In 12 rabbit femoral condyles, moderate-heat-treated bone allografts were implanted into 6-mm drill holes. Twelve normal allografts and 12 empty drill holes served as controls. Radiologic and histological evaluation up to 12 weeks postoperatively revealed slow spontaneous bone remodeling from the rim to the center of the empty cavities. Normal deep frozen allografts were quickly intergrated after a short period of osteoclast reaction around the transplant, with occasional bone bridges between host and allograft. The examination of heat-treated allografts showed no differences to the controls, including morphologic aspects and the time course of osteointegration. Five zones of bone repair and osteointegration were distinguished. We conclude that thermal treatment of bone allografts has adverse effects on osteointegration in the rabbit femoral condyle. Thus, it may contribute to improving safety in human bone transplantation.

Animals↗
PubMed1992

[Combined injury of the anterior cruciate ligament and the medial collateral ligament of the knee joint--results of two to six years follow-up of surgical treatment].

A retrospective study of 148 combined acute knee injuries with anterior cruciate and medial collateral ligament injuries was performed. Follow-up included 115 patients, 95 of whom were personally examined two to six years postoperatively. Proximal anterior cruciate ligament ruptures were treated with reinsertion in 96 patients, in case of intraligamentous lesions (44 times), augmentation with the semitendinosus tendon was performed. Medial collateral ligament lesions were explored during the operation. Reconstruction of intraligamentous ruptures was performed with sutures (120 times). Distal lesions were refixed with Burri plate or staple. A modified Ellison procedure was routinely performed. Postoperative treatment was cast-free and included immediate physiotherapy using a functional brace. Between the two groups with anterior cruciate ligament reinsertion and augmentation, no significant differences were observed in subjective evaluation (Lysholm score 85 vs. 88), activity level (Tegner score 5.5 vs. 5.4) or anterior stability (KT 1000 at 89 N 6.6 vs. 6.1 mm displacement). A clear pivot shift sign was noted in two knees with reinsertion and in none of the augmented group. Medial stability was reestablished almost completely, independent of the site of lesion or the reconstruction technique (average valgus movement at 30 degrees flexion 0.7+ vs. 0.5+ on injured/contralateral side). We conclude that reinsertion of femoral anterior cruciate ligament ruptures will reestablish anterior stability in most cases, although semitendinosus augmentation appears to give slightly more reliable results. Medial stability is gained by the site-depending reconstruction techniques. Whether intraligamentous medial collateral ligament lesions can be left alone with only the anterior cruciate ligament being reconstructed, cannot be answered by this study.

Adolescent↗
PubMed1992

Human perforin (PRF1) maps to 10q22, a region that is syntenic with mouse chromosome 10.

Perforin (PRF1) is a cytolytic, channel-forming protein of cytolytic T cells, natural killer cells, and granulated metrial gland cells and plays a crucial role in the killer cell-mediated elimination of virally infected host cells, tumor cells, and allotransplants. Two-thirds of the perforin sequence is homologous to the lytic, channel-forming complement proteins C6, C7, C8 alpha, C8 beta, and C9. Using cosmid DNA containing the PRF1 gene as a probe for fluorescence in situ hybridization, we have reevaluated its chromosomal location. Previously assigned to chromosome 17q11-q21, it has now been mapped to 10q22. The human PRF1 locus lies within a conserved synteny segment present on mouse chromosome 10, consistent with the previous chromosomal assignment of mouse perforin. The perforin locus is not linked to any of the genes of the terminal complement system.

Animals↗
PubMed1992

[A phosphine-substituted diphosphonic acid (HMPD) for improved scintigraphic detection of bone lesions].

Although the radiopharmaceuticals used for bone scintigraphy are of very high quality, the search for an "ideal" agent continues. To optimise the detectability of bone lesions, we analysed 244 different 99mTc-labeled phosphonates in animal experiments. In osteosarcoma-carrying rats 99mTc-labeled 1-Hydroxy-3-methyl-phosphinic-1, 1-propanediphosphonic acid (HMPD) was shown to produce the best lesion/normal bone ratio. 99mTc-MDP was used as reference. The ratio was found to be 1.28 for 99mTc-HMPD. The transferability of our results in animals to the situation in man was studied in 10 patients with bone metastases. There was for 99mTc-HMPD an improvement of the lesion/normal bone ratio by more than 60% but also an additional reduction of the soft tissue contrast by about 40%. 15% of the metastases were detected by scintigraphy using 99mTc-HMPD only and not with 99mTc-MDP. The new agent should make possible a better and earlier discrimination of bone lesions in the scintigram.

Aged↗
PubMed1991

Primary structure and functional expression of a glutaminyl cyclase.

A glutaminyl cyclase (QC) that is probably involved in the biosynthesis of pyroglutamyl peptides such as gonadotropin-releasing hormone and thyrotropin-releasing hormone has been purified to homogeneity from bovine anterior pituitary. On the basis of N-terminal sequence analysis, a 2088-base-pair cDNA clone was isolated from a bovine anterior pituitary library. From the nucleotide sequence of this clone, the primary structure of a 330-residue protein and a preceding 31-residue prepropeptide sequence was deduced. By transfection of COS-7 monkey cells with a QC cDNA/pCDM8 vector construct, QC activity was expressed. Hybridization with mRNAs of various bovine tissues revealed expression of QC mainly in brain tissue.

Acyltransferases↗
PubMed1991

Genomic organization and subchromosomal in situ localization of the murine granzyme F, a serine protease expressed in CD8+ T cells.

Granzyme F belongs to a closely related family of seven murine serine proteases stored in cytoplasmic granules of lymphoid cell populations. In contrast to the murine granzymes A to E and G, granzyme F is exclusively expressed in the CD4-CD8+ subset of peripheral T cells. To characterize the genomic sequences responsible for its highly restricted expression, we isolated a cosmid clone and sequenced a 7.5-kb genomic fragment that contains the promoter region and all five exons of the murine granzyme F gene. A TATA box sequence is located at position -25 relative to the transcription initiation site, which was determined by RNase protection. The genomic organization of granzyme F is similar to that of granzyme B and granzyme C, leukocyte elastase, cathepsin G, rat mast cell protease II, and complement factor D (adipsin). By the use of two fluorochromes for simultaneous high resolution in situ hybridization, the granzyme F gene was localized in close proximity distally from the TCR alpha-chain locus on mouse chromosome 14.

Amino Acid Sequence↗
PubMed1991

Human elongation factor 1 beta: cDNA and derived amino acid sequence.

From a cDNA library in lambda gt11 derived from poly (A+)RNA of human ovarian granulosa cells a cDNA clone lambda HGP34, containing an EcoRI insert of 829 bp, was identified. After subcloning of the insert into pUC18, the clone pHGP34 was obtained and sequenced. The derived amino acid sequence, corresponding to a protein of 225 amino acids, shows a high degree of homology to elongation factor 1 beta (EF-1 beta) of Artemia salina (57%) and known peptide sequences of Xenopus laevis EF-1 beta (86%). We therefore assume that the protein coded for by pHGP34 represents human EF-1 beta. Northern analysis reveals an EF-1 beta specific mRNA of 900 bp. Southern analysis indicates that EF-1 beta in the human genome, like EF-1 alpha, appears to be specified by more than one gene. A high degree of sequence homology for EF-1 beta specific sequences is observed for bovine, rat and mouse species.

Amino Acid Sequence↗
PubMed1991

The mitochondrial genome of fission yeast: inability of all introns to splice autocatalytically, and construction and characterization of an intronless genome.

In this paper we report the inability of four group I introns in the gene encoding subunit I of cytochrome c oxidase (cox1) and the group II intron in the apocytochrome b gene (cob) to splice autocatalytically. Furthermore we present the characterization of the first cox1 intron in the mutator strain anar-14 and the construction and characterization of strains with intronless mitochondrial genomes. We provide evidence that removal of introns at the DNA level (termed DNA splicing) is dependent on an active RNA maturase. Finally we demonstrate that the absence of introns does not abolish homologous mitochondrial recombination.

Amino Acid Sequence↗
PubMed1991

Characterization of a novel open reading frame, urf a, in the mitochondrial genome of fission yeast: correlation of urf a mutations with a mitochondrial mutator phenotype and a possible role of frameshifting in urf a expression.

Between the genes for tRNA(gin) and tRNA(ile) an open reading frame of 227 amino acids has been identified which is unique among known mitochondrial genomes and which has been termed urf a (Lang et al. 1983; Kornrumpf et al. 1984). It uses the "mitochondrial" genetic code, i.e., it contains a TGA codon, whereas all other protein-encoding genes, and all but one intronic open reading frame, use the "standard" genetic code (UGG for tryptophan). A previous paper has demonstrated that "mutator" strains show an increased formation of mitochondrial drug-resistant and respiration-deficient mutants (including deletions). In this paper we show that the mutator activity is correlated with mutations in urf a. A detailed analysis of one urf a mutant is presented (anar-6), where the deletion of an A residue leads to a frameshift mutation and consequently to premature termination of the putative protein. The phenotype of colonies originating from a single mutant clone varies from no growth up to full growth on non-fermentable substrate. This phenomenon of phenotypic segregation can be explained by the ability of the cell to perform translational frameshifting. A detailed analysis of the DNA sequence and the putative urf a protein will be presented and a possible function of the protein will be discussed.

Amino Acid Sequence↗
PubMed1991

Increased proteinase expression during tumor progression of cell lines down-modulated for TIMP levels: a new transformation paradigm? [corrected].

We have reported that down-modulation of tissue inhibitor of metalloproteinases (TIMP) by means of antisense RNA converts non-tumorigenic Swiss 3T3 cells into malignant cells capable of forming metastasizing tumors in nude mice [Science 243:947 (1989)]. We now describe changes in the expression of specific genes associated with tumor progression of two lines down-modulated with TIMP, LA1 and LA7. Six independent variant cell lines, generated from different primary tumors produced by LA1 and LA7, lacked (like LA1 and LA7) many characteristics of typical transformed cells. However, their tumorigenicity in nude mice was enhanced; tumors appeared with a shorter lag (1-3 weeks versus 8-10 weeks for the parental clones, LA1 and LA7) and grew very rapidly. Increases, substantial in some cases, in the expression of a cysteine proteinase, cathepsin L, and metalloproteinases homologous to rat transin (stromelysin) and transin-2 were characteristic of these variant clones. The mRNA levels encoding the transformation-associated secreted phosphoprotein (osteopontin) and the calcium-binding protein calcyclin were also augmented. No evidence for gene amplification was found, and we did not detect any change in the mRNA levels of the proto-oncogenes that were examined. These novel cell lines represent a new paradigm for the transformed cell. Our data suggest that a reduction in TIMP secretion enhances the cell's oncogenic capacity by altering the extracellular environment in a way conducive to further changes in gene expression necessary for tumor progression.

Animals↗
PubMed1991

Spontaneous immortalization of mouse embryo cells: strain differences and changes in gene expression with particular reference to retroviral gag-pol genes.

We have studied the kinetics with which cultures of primary mouse embryo cells pass through the crisis period, escape their terminal differentiation (cellular senescence), and give rise to an immortal cell line. The process is strain-dependent, with cells from the outbred Swiss CD-1 mouse being considerably more adept at forming an immortal 3T3 line than cells from the inbred SWR line; Balb/c cells appeared intermediate in their behavior. The continued presence of the tumor promoter 12-O-tetradecanoylphorbol-13-acetate or the poly(ADPribose)polymerase inhibitor 3-aminobenzamide affected the kinetics but did not seem to alter the outcome. Changes in expression of various genes, including those encoding mitogen-regulated protein (proliferin), endogenous gag-pol retrovirus sequences, insulin-like growth factor II, and a variety of protooncogenes, were monitored during the process of immortalization, and although certain changes were reproducibly characteristic of cells from a given mouse strain passed according to a specific regimen, none of the observed changes were reproducibly characteristic under all conditions of immortalization. In particular, our data indicate the absence of a strict correlation between cellular immortalization and the activation of endogenous gag-pol expression. We conclude from our observations that the establishment of permanent lines from primary mouse embryo cells in serum-containing medium reflects the selection of a variant subpopulation of cells that did not preexist but rather arose in response to the specific culture conditions by a process resembling differentiation. Multiple and complex changes in gene expression occur that are affected by the culture conditions and the strain (genotype) of the mouse.

Animals↗
PubMed1990

Physical maps of 4p16.3, the area expected to contain the Huntington disease mutation.

The gene for Huntington disease, a neurodegenerative disorder with autosomal dominant inheritance, has been localized to the terminal portion of the short arm of human chromosome 4 (4p16.3) by linkage analysis. Since eventual isolation of the gene requires the application of high-resolution genetic analysis coupled with long-range DNA mapping and cloning techniques, we have constructed a physical map of the chromosomal region 4p16.3 using more than 20 independently derived probes. We have grouped these markers into three clusters which have been ordered and oriented by genetic and somatic cell genetic mapping information. The mapped region extends from D4S10 (G8) toward the telomere and covers minimally 5 Mb.

Chromosome Mapping↗