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M Burmeister

Publications and source records attributed to M Burmeister.

At least 37 records · Page 2Linked to original sources
PubMed1999

A gene for autosomal dominant hearing impairment (DFNA14) maps to a region on chromosome 4p16.3 that does not overlap the DFNA6 locus.

Non-syndromic hearing impairment is one of the most heterogeneous hereditary conditions, with more than 40 reported gene localisations. We have identified a large Dutch family with autosomal dominant non-syndromic sensorineural hearing impairment. In most patients, the onset of hearing impairment is in the first or second decade of life, with a slow decline in the following decades, which stops short of profound deafness. The hearing loss is bilateral, symmetrical, and only affects low and mid frequencies up to 2000 Hz. In view of the phenotypic similarities of this family with an American family that has been linked to chromosome 4p16.3 (DFNA6), we investigated linkage to the DFNA6 region. Lod score calculations confirmed linkage to this region with two point lod scores above 6. However, as haplotype analysis indicated that the genetic defect in this family is located in a 5.6 cM candidate region that does not overlap the DFNA6 region, the new locus has been named DFNA14.

Adolescent↗
PubMed1998

Antisense expression of the human pro-melanin-concentrating hormone genes.

Expression of transcripts for human pro-melanin concentrating hormone (pMCH) were studied in the hypothalamus, the primary location for pMCH producing cells in the mammalian CNS. Human hypothalamic tissue was extracted for total RNA and the cDNA generated with reverse transcriptase (RT). PCR amplification with primers spanning exons 2 and 3 of the pMCH human-variant genes (pMCHL), yielded an unspliced product, confirming prior work [T.B. Campbell, C.K. McDonald, M. Hagen, The effect of structure in a long target RNA on ribozyme cleavage efficiency, Nucleic Acids Res. 25 (1997) 4985-4993]. In addition, this product was shown to be exclusively antisense, and to be derived from the 5p (pMCHL1), not the 5q (pMCHL2) locus. Thus, there is no evidence that the MCH peptide-precursor molecule is produced in the brain by the human-variant pMCHL loci. In contrast, corresponding RT-PCR for pMCH RNA generated by the locus on 12q, demonstrated the presence of both sense and antisense spliced RNA. Partial sequencing of the spliced product confirmed that production of at least the two C-terminal peptides would occur from the 12q pMCH locus. The significance of the findings for pMCH and pMCHL1 are discussed relative to what is known about the function of endogenous antisense RNA.

Alternative Splicing↗
PubMed1998

Fine genetic and comparative mapping of the deafness mutation Ames waltzer on mouse chromosome 10.

The Ames waltzer (av) mouse mutant is an autosomal recessive deafness mutation on mouse Chromosome 10. Previously, av had not been mapped relative to molecular markers. We have performed an intersubspecific backcross with Mus musculus castaneus and mapped microsatellite markers in this cross. Toothpick PCR on previously frozen tissue samples from offspring was used as an efficient strategy to screen a large number of animals quickly. In 1258 progeny tested we found three recombinants for each of the flanking markers D10Mit199 and D10Mit64. In addition, nine different genes (Ank3, Bcr, Gnaz, Tfam, Mif, Mmp11, Dcoh, Pyp, and Gstt2) were mapped and eliminated genetically as candidate genes for av. av had been discussed as a potential mouse model for the human deafness loci Usher syndrome type ID (USH1D) and DFNB12. Comparative mapping shows that av maps near an evolutionary break point and makes it unlikely that those loci are human homologues of av. A human homologue of av is predicted to lie either on 22q11.2 or on 10q21. The orientation of conserved linkage groups between these two human chromosomal regions relative to mouse Chromosome 10 was determined.

Animals↗
PubMed1998

Mutation in AP-3 delta in the mocha mouse links endosomal transport to storage deficiency in platelets, melanosomes, and synaptic vesicles.

The mouse mutant mocha, a model for the Hermansky-Pudlak storage pool deficiency syndrome, is characterized by defective platelets, coat and eye color dilution, lysosomal abnormalities, inner ear degeneration, and neurological deficits. Here, we show that mocha is a null allele of the delta subunit of the adaptor-like protein complex AP-3, which is associated with coated vesicles budding from the trans-Golgi network, and that AP-3 is missing in mocha tissues. In mocha brain, the ZnT-3 transporter is reduced, resulting in a lack of zinc-associated Timm historeactivity in hippocampal mossy fibers. Our results demonstrate that the AP-3 complex is responsible for cargo selection to lysosome-related organelles such as melanosomes and platelet dense granules as well as to neurotransmitter vesicles.

Adaptor Protein Complex 3↗
PubMed1998

Radiation hybrid mapping of the two highly homologous human-variant pMCHL genes by PCR-SSCP.

When gene loci are very similar in sequence, as in gene families or multiple pseudogenes, it is difficult to determine the specific location of the individual genes. We show here that applying PCR-SSCP to a radiation hybrid panel allowed mapping and specific sequencing of two genes with only a few sequence differences. Human-variant forms of the promelanin-concentrating hormone (pMCH) gene are found in two locations in the genome, previously localized by FISH to 5p14 and 5q12-q13. Without prior knowledge of sequence variation between the loci, we observed a difference in migration pattern in PCR-SSCP, indicating the presence of at least one point of sequence divergence. PCR-SSCP of 93 samples from a human-hamster radiation hybrid panel revealed the location of the genes to be between markers WI-4804 and AFM225YC5 on chromosome 5p, and between markers WI-3133 and WI-4225 on chromosome 5q. Sequencing of the two 680-bp PCR products from the hybrid panel demonstrated 3 bases of sequence difference between the 5p and 5q locations.

Alleles↗
PubMed1997

Novel cystatin B mutation and diagnostic PCR assay in an Unverricht-Lundborg progressive myoclonus epilepsy patient.

Two mutations in the cystatin B gene, a 3' splice mutation and a stop codon mutation, were previously found in patients with progressive myoclonus epilepsy of Unverricht-Lundborg type [Pennacchio et al. (1996): Science 271:1731-1734]. We present here a new mutation 2404deltaTC: a 2-bp deletion within the third exon of the cystatin B gene in an Unverricht-Lundborg patient. This mutation results in a frameshift and consequently premature termination of protein synthesis. Complete sequencing of the coding region and splice junctions of the cystatin B gene showed that neither of the two previously known mutations was present in this patient. The level of cystatin B mRNA in an immortalized cell line was found to be decreased, as had been reported for other Unverricht-Lundborg patients. The new mutation further supports the argument that defects in the cystatin B gene cause the Unverricht-Lundborg form of progressive myoclonus epilepsy. We describe a simple PCR method which can detect the 2404deltaTC deletion. This assay, together with previously described PCR assays for the other two known mutations, should prove useful in confirming clinically difficult diagnoses of Unverricht-Lundborg disease.

Amino Acid Sequence↗
PubMed1997

Complete cDNAs for CDC42 from chicken cochlea and mouse liver.

CDC42 is a member of the ras superfamily of small GTP-binding proteins that are related through the highly conserved GTP-binding domain and are involved in signal transduction pathways. Two full-length CDC42 cDNAs have been isolated: a 2148-bp chick cochlea cDNA and a 2063-bp mouse liver cDNA. Each encodes a CDC42 protein of 191 amino acids. The avian CDC42 protein differs from the mouse at only one amino acid residue, a Thr for a Ser at position 185. Both CDC42 proteins are more similar to the ubiquitous human isoform originally isolated from placenta than to the isoform isolated from fetal brain. Using a probe from the 3' UTR of the mouse liver CDC42 cDNA, we demonstrated that the mouse gene is expressed in all tissues examined. Southern blot analysis of a mouse inter-specific backcross with this gene-specific probe identified at least three CDC42-like (Cdc42l) genes in the mouse genome. Cdc42l1 was mapped to distal mouse Chromosome 4, near Cappb1. Cdc42l2 mapped more proximal on Chromosome 4, whereas Cdc42l3 mapped to the X Chromosome.

Amino Acid Sequence↗
PubMed1997

[Preoperative hemodilution with bovine hemoglobin. Acute hemodynamic effects in liver surgery patients ].

UNLABELLED: Haemoglobin solutions can be an alternative to allogeneic red-cell transfusions because they combine colloid osmotic with oxygen transport properties. Since severe toxic side effects have been overcome by ultrapurification, clinical interest has been focused on haemodynamics changes during application of haemoglobin preparations. The present clinical study examines changes of haemodynamic and oxygen transport parameters during and after haemodilution with ultrapurified polymerized bovine haemoglobin (HBOC-201) in comparison to hydroxyethyl starch (HES). METHODS: After approval of the Ethics Committee, 12 patients (6 males and 6 females, mean age 59 +/- 10 years, ASA 1-2) undergoing elective liver resection were randomly allocated to receive either 3 ml.kg-1 6% HES 70,000/0.5 (group 1) or 0.4 g.kg-1 HBOC-201 (group 2) within 30 min following autologous blood donation of 1 l and substitution with 2 l Ringer's lactate. Measurements of blood gases, haemodynamics, and oxygen transport parameters were performed after induction of general anaesthesia, prior to and after blood donation, during and after infusion, at the beginning of surgery, and in the intensive care unit. RESULTS: Demographic characteristics did not differ between groups. In contrast to the HES group, mean arterial pressure increased by 18% over baseline measurements in group 2. While pulmonary vascular resistance showed a trend to higher values in group 2, systemic vascular resistance increased to a maximum of 42% over baseline in group 2 and was twice as high as in the HES group. The cardiac index was lower in the HBOC-201 group than in the HES group. During and after HBOC-201 infusion, mixed-venous oxygen saturation and content and calculated oxygen delivery were lower in group 2 in comparison to group 1, while the oxygen extraction ratio was higher in group 2. Free haemoglobin reached a maximal concentration of 1.0 +/- 0.2 g.dl-1 30 min after the HBOC-201 infusion was started, but was not detectable in urine over time. The mean intravascular half-life of HBOC-201 was 8.5 h. CONCLUSIONS: Patients did not show any severe complications during and after infusion of HBOC-201. However, vasoconstrictive side effects resulted in increased systemic but not pulmonary resistance. Ongoing studies with higher doses of HBOC-201 applied in a larger number of patients will probably reveal potential clinical consequences of the demonstrated haemodynamic changes.

Adult↗
PubMed1997

G to C transversion at a splice acceptor site causes exon skipping in the cystatin B gene.

Several mutations have been described in the proteinase inhibitor cystatin B gene from individuals affected with progressive myoclonus epilepsy of the Unverricht-Lundborg type (EPM1). One of these mutations, a 1925G-->C transition at the 3'-splice acceptor site of the intron 1, was postulated to lead to inappropriate splicing of a primary transcript of the cystatin B gene in EPM1 patients. In an effort to understand the expression of the 1925G-->C mutation, the sequence of cystatin B mRNA transcripts from lymphoblastoid cell lines of heterozygous patients carrying the mutation were analyzed. RT-PCR of total mRNA showed two main products: the apparently normal transcript and an aberrant, 102 bp shorter transcript. Direct PCR sequencing showed that the aberrant transcript is a consequence of exon 2 skipping.

Cell Line↗
PubMed1997

Comparison of continuous spinal with combined spinal-epidural anesthesia using plain bupivacaine 0.5% in trauma patients.

We investigated the efficacy and complications of microcatheter spinal anesthesia (CSA) in comparison to a combined spinal-epidural technique (CSE) using plain bupivacaine 0.5%. Sixty trauma patients randomly received either CSA using a 22-gauge Sprotte needle and a 28-gauge microcatheter or CSE after insertion of a 22-gauge epidural catheter through an 18-gauge Tuohy needle followed by dural puncture with a 25-gauge pencil-point needle inserted through the backeye of the Tuohy needle. An initial subarachnoid bolus of 2 mL of plain bupivacaine 0.5% was injected. If analgesia did not reach T12 within 20 min, supplemental bupivacaine was injected either intrathecally or epidurally up to a maximum of 5 mL in the CSA group or 16 mL in the CSE group. Mean arterial blood pressure, heart rate, and analgesic levels were recorded. On postoperative Day 4, patients were interviewed for postanesthetic complaints. Technical problems were more frequent in the CSE group than in the CSA group (47% vs 13%). Performance of anesthesia was faster (8 +/- 3 vs 15 +/- 8 min) and the total dose of bupivacaine lower (3.2 +/- 1.0 vs 9.7 +/- 5 mL) in patients who received CSA. The incidence of hypotension did not differ significantly. However, more patients in the CSE group were treated for bradycardia (4 vs 0). The number of patients suffering from postdural puncture headache was comparable in both groups, but there were more patients with lower back pain in the CSE group (8 vs 2). In conclusion, our data suggest that microcatheter CSA is not associated with an increased rate of complication in patients with lower limb fractures.

Adult↗
PubMed1996

Molecular characterization of a nonneuronal human UNC18 homolog.

A cDNA clone encoding a human homolog of the Caenorhabditis elegans unc-18 gene was identified following random sequencing of clones from IL-2-activated human NK cells. This cDNA clone is related to the nonneuronal Munc-18b and so has been called Hunc-18b. The Hunc-18b transcripts were found in most human tissues, with the exception of brain and skeletal muscle, and in cells from all lymphoid lineages. The Hunc-18b gene was localized to human chromosome 19p13.2-p13.3, and the mouse homolog, Munc-18b, was mapped to the proximal region of mouse Chromosome 8.

Amino Acid Sequence↗
PubMed1996

Visualization of DNA in agarose gels as migrating colored bands: applications for preparative gels and educational demonstrations.

Visualization of DNA in electrophoretic gels typically requires UV radiation and the fluorescent dye ethidium bromide. Alternatively, we report here that by inclusion of visible dyes in standard agarose gels, DNA bands are observable in ambient light as they are separating. Such bands can be directly recovered from gels (approximately 50% yield) and used in standard enzymatic reactions (ligation, endonucleolytic cleavage, random labeling, PCR, and cycle-sequencing) without purification. Of 14 common commercially available stains that could visualize fractionating DNA, Nile blue was chosen for more extensive analysis as it gave the sharpest and most persistent bands and is not known to be toxic. Bands containing greater than 40 ng DNA could be detected by direct visual inspection of gels during electrophoresis. Drying the gels increased sensitivity to 4 ng. We describe relevant molecular features of these dyes and detail simple assays that may be employed to find other useful, and perhaps superior, dyes. This method also lends itself to situations in which easy visualization and convenience of DNA electrophoresis are important, such as classroom demonstrations.

Blotting, Southern↗
PubMed1996

Fine genetic map of mouse chromosome 10 around the polycystic kidney disease gene, jcpk, and ankyrin 3.

A chlorambucil (CHL)-induced mutation of the jcpk (juvenile congenital polycystic kidney disease) gene causes a severe early onset polycystic kidney disease. In an intercross involving Mus musculus castaneus, jcpk was precisely mapped 0.2 cM distal to D10Mit115 and 0.8 cM proximal to D10Mit173. In addition, five genes, Cdc2a, Col6a1, Col6a2, Bcr, and Ank3 were mapped in both this jcpk intercross and a (BALB/c x CAST/Ei)F1 x BALB/c backcross. All five genes were eliminated as possible candidates for jcpk based on the mapping data. The jcpk intercross allowed the orientation of the Ank3 gene relative to the centromere to be determined. D10Mit115, D10Mit173, D10Mit199, and D10Mit200 were separated genetically in this cross. The order and genetic distances of all markers and gene loci mapped in the jcpk intercross were consistent with those derived from the BALB/c backcross, indicating that the CHL-induced lesion has not generated any gross chromosomal abnormalities detectable in these studies.

Animals↗
PubMed1996

The neurological mouse mutations jittery and hesitant are allelic and map to the region of mouse chromosome 10 homologous to 19p13.3.

Jittery (ji) is a recessive mouse mutation on Chromosome 10 characterized by progressive ataxic gait, dystonic movements, spontaneus seizures, and death by dehydration/starvation before fertility. Recently, a viable neurological recessive mutation, hesitant, was discovered. It is characterized by hesitant, unco-ordinated movements, exaggerated stepping of the hind limbs, and reduced fertility in males. In a complementation test and by genetic mapping we have shown here that hesitant and jittery are allelic. Using several large intersubspecific backcrosses and intercrosses we have genetically mapped ji near the marker Amh and microsatellite markers D10Mit7, D10Mit21, and D10Mit23. The linked region of mouse Chromosome 10 is homologous to human 19p13.3, to which several human ataxia loci have recently been mapped. By excluding genes that map to human 21q22.3 (Pfkl) and 12q23 (Nfyb), we conclude that jittery is not likely to be a genetic mouse model for human Unverricht-Lundborg progressive myoclonus epilepsy (EPM1) on 21q22.3 nor for spinocerebellar ataxia II (SCA2) on 12q22-q24. The closely linked markers presented here will facilitate positional cloning of the ji gene.

Alleles↗