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A Koch

Publications and source records attributed to A Koch.

At least 19 recordsLinked to original sources
PubMed1997

An optimized protocol for mRNA quantification using nested competitive RT-PCR.

Nested competitive reverse transcription polymerase chain reaction is an effective tool for the quantification of low level expressed mRNAs. Competitive RNA standards with small deletions allow the use cRT-PCR. The sensitivity is further increased by the utilization of nested PCR protocols. To optimize quantification of low abundance mRNAs we modified established protocols for use of automated labstations and semiautomated sequencers. In placental tissue, known for a very high CYP19 (P450AROM, aromatase) expression, cRT-PCR and nested cRT-PCR yielded virtually identical results which could be confirmed by Northern blotting. CYP19 mRNA in breast tumour tissue ranged below detection levels for Northern blotting; however, using our modified assay CYP19 showed 1.5 to 15 fold higher expression levels than in normal glandular breast tissue. Our approach proved to be useful for the quantification of a gene with low level expression. The employment of labstations and semiautomated sequencers allows rapid analysis of large sample numbers.

Aromatase↗
PubMed1997

Primary angioplasty versus thrombolysis in the treatment of acute myocardial infarction. ALKK Study Group.

This study investigates the hypothesis if primary angioplasty is superior to intravenous thrombolysis in the treatment of acute myocardial infarction (AMI). Small prospective randomized studies did not demonstrate a significant benefit regarding total mortality. A total of 14,980 patients with AMI were registered by "The 60-Minutes Myocardial Infarction Project," a prospective multicenter observational study: 210 of these patients were treated with primary angioplasty. A matched pair analysis comparing 1 primary angioplasty patient with 3 intravenous thrombolysis patients could be performed in 156 primary angioplasty patients. Criteria for matching were age, sex, location of AMI, systolic blood pressure, previous AMI, and prehospital delay. Patients with a bundle branch block or requiring resuscitation were excluded from analysis. Because of matching, both groups showed similar baseline characteristics. Patients with primary angioplasty had more relative contraindications for thrombolysis (ulcers: 10.3% vs 2.3%, recent intramuscular injections: 6.4% vs 1.6%, recent surgical interventions: 5.1% vs 1.1%, central punctures: 9% vs 3.9%). There was a tendency toward less combined adverse events in the primary angioplasty group (3.2% vs 5.7%, odds ratio [OR] = 0.55, 95% confidence interval [CI] = 0.21 to 1.44). In-hospital mortality rates in the primary angioplasty group and thrombolysis group were 4.3% and 10.3%, respectively (OR = 0.39, 95% CI = 0.17 to 0.92). The difference in mortality could already be demonstrated within the first 48 hours with 1.9% versus 5.3% deaths (OR = 0.35, 95% CI = 0.11 to 1.14). Thus this study indicates a superiority of primary angioplasty in comparison to intravenous thrombolysis in AMI even in a clinical routine setting, with a reduction of hospital mortality of about 60%.

Aged↗
PubMed1997

Molecular characterization of the Bacillus stearothermophilus PV72 S-layer gene sbsB induced by oxidative stress.

S-layer protein variation from a hexagonally ordered (SbsA; 130 kDa) to a obliquely ordered (SbsB; 98 kDa) protein in Bacillus stearothermophilus PV72 is mediated by an increased oxygen supply. To elucidate the molecular basis of S-layer protein variation in B. stearothermophilus PV72, the sbsB gene, coding for the 98-kDa protein, was cloned by means of inverse PCR technology and sequenced. The sbsB coding region cloned in pUC18 was expressed in Escherichia coli, without its own regulatory upstream sequences but with its putative transcriptional terminator. The reading frame of sbsB (2,760 nucleotides) is predicted to encode a protein of 920 amino acids, including the signal sequence. Amino acid sequence comparison of SbsA and SbsB did not reveal any significant homology. The expression of sbsB in E. coli resulted in an accumulation of SbsB self-assembly products in the cytoplasm.

Amino Acid Sequence↗
PubMed1996

Loss of heterozygosity at locus F13B on chromosome 1q in human medulloblastoma.

Medulloblastoma is a primitive neuroectodermal tumor of the cerebellum with poorly understood pathogenesis. Previous studies have reported loss of heterozygosity (LOH) on chromosome arms 17p, 11p and 9q and cytogenetic abnormalities of chromosome 1 in medulloblastoma. We have used the polymerase chain reaction to amplify 10 microsatellites on the short arm and 8 microsatellites on the long arm of chromosome 1 to assess allelic loss in 22 medulloblastomas. Loss of heterozygosity (LOH) on chromosome 1 was found in 9 cases. Eight medulloblastomas (36%) showed an interstitial LOH on chromosome 1q. The common region of overlap was mapped between D1S 1604 and D1S237 and included the locus F13B in the chromosomal region 1q31-q32.1. An additional tumor had LOH in a proximal region of 1p, but did not exhibit LOH on 1q. None of the medulloblastomas exhibited LOH of the telomeric portion of chromosome 1p, which has been associated with several other human malignancies. Our data suggest the presence of a putative tumor suppressor gene located near the locus F13B on chromosome arm 1q that appears to be involved in the pathogenesis of medulloblastoma.

Adolescent↗
PubMed1996

Endoglucanase II (EGII) of Penicillium janthinellum: cDNA sequence, heterologous expression and promotor analysis.

The cDNA coding for the endoglucanase EGII of P. janthinellum was cloned and sequenced. The open reading frame comprises 1230 nucleotides and the deduced amino-acid sequence shows an overall homology of 63% with the T. reesei egl2. The cellulose-binding domain of EGII represents a typical member of the A family of cellulases. The egl2 gene is only induced by cellulose or cellobiose and not by sophorose. A promotor fragment including 1 kb was cloned and sequenced. Three major transcription startpoints were identified. Five motifs matching the binding site of the carbon-catabolite repressor CREA of A. nidulans were detected. Their potential implication in repression was analyzed by bandshift assays.

Base Sequence↗
PubMed1996

Enhanced sensitivity of the failing human myocardium to cardiac glycosides and Na(+)-channel activators.

Cardiac glycosides and Na+ -channel activators increase intracellular Na+ and thereby enhance the transport rate of the sarcolemmal Na+/Ca2+ exchanger. We tested the hypothesis of whether increased expression of the Na+/Ca2+ exchanger in failing human myocardium is accompanied by enhanced sensitivity of the failing human myocardium toward cardiac glycosides and Na+ -channel activators. We studied the positive inotropic effects of the new Na+ -channel activator BDF and the cardiac glycoside ouabain in human failing (New York Heart Association [NYHA] functional class IV, heart transplants for dilated cardiomyopathy, n = 11) and nonfailing (donor hearts, n = 5) myocardium on electrically driven left ventricular papillary muscle strips (1 Hz, 37 degrees C). The effectiveness of ouabain and BDF to increase force of contraction was similar in human nonfailing and failing myocardium. BDF was more potent to increase force of contraction in failing than in nonfailing tissue (p < 0.05). The time until maximal inotropic effect developed after ouabain was significantly shorter in NYHA IV (mean 150 +/- 16 min) than in nonfailing myocardium (mean 240 +/- 20 min). These results suggest that human failing myocardium exerts and enhanced sensitivity to cardiac glycosides and Na+ -channel activators, possibly because of enhanced expression of the Na+/Ca2+ exchanger or because of an altered intracellular Na+ -homeostasis.

Adolescent↗
PubMed1996

Correlation of histology, cytogenetics and proliferation fraction (Ki-67 and PCNA) quantitated by image analysis in meningiomas.

Sixty meningiomas were classified histologically according to the WHO criteria and analyzed cytogenetically. The Ki-67 and PCNA proliferation fractions (PRFs) were assessed by immunhistochemistry. The staining results were quantified by TV-image analysis (Miamed, Leica, Germany). Within meningiomas of WHO-grade II/III and those with complete or partial deletion of # 1p, we found a significantly higher mean and maximal Ki-67 PRFs than in those of WHO-grade I and those with all other karyotypes. This was not the case for PCNA PRFs. No differences in PRFs were detectable between histological subtypes. Although these results were obtained after measurement of five high power fields (HPFs) only, the heterogeneity of PRF distribution within the tumors was high. Even after the measurement of 100 HPFs, the 95% confidence intervals were in a range of 18% to 34.3% PRF. This finding seems to be responsible for the moderate interobserver reproducibility of image analytical determination of PRF (r = 0.74). Nevertheless, there was a good correlation between subjective and objective image analytical assessment of PRF (r = 0.83). The significance of the maximum Ki-67 PRF per specimen implies the possibility of selecting those areas which show the highest fraction of positively stained nuclei for measurement, avoiding the problem of intraslide heterogeneity. Thus the time needed for image analytical quantification may be reduced.

Biomarkers, Tumor↗
PubMed1996

[Detection of hearing loss in patrons of a discoteque using TEOAE and DPOAE].

BACKGROUND: The aim of the study was to investigate the potential and difference of pure tone audiogram, TEOAE and DPOAE in the detection of temporary threshold shift. METHODS: 46 disco visitors who were exposed to disco music at an average intensity of 105 dB (A) for 1, 1 1/2 and 2 hours respectively underwent audiological examination before and after noise exposure. Audiological measurements performed were an audiogram and measurements of the TEOAE and DPOAE using the system ILO 92 (Otodynamics). RESULTS: The frequency range where the threshold shift occurred was around 4000 Hz in the 1 hour group and spread over all frequencies when the exposure time increased. The average threshold shift over all frequencies and probands was 6.2 dB for the 1 hour group, 7.1 dB for the 1 1/2 hour group and 10.1 dB after 2 hours of noise exposure. TEOAE amplitudes showed significant reduction only at 2000 and 3000 Hz. Even at threshold shifts exceeding 15 dB, however not in all cases, a reduction of TEOAE amplitudes occurred. Similar results were obtained regarding the DPOAE measurements. CONCLUSIONS: We conclude that TEOAE and DPOAE are not ideal instruments in the detection of temporary threshold shift after noise exposure.

Adolescent↗
PubMed1996

Variable imprinting of H19 and IGF2 in fetal cerebellum and medulloblastoma.

Only the maternal or paternal allele of an imprinted gene is expressed in somatic cells. The gene for insulin-like growth factor II (IGF2) and the H19 gene (a putative tumor suppressor gene) are imprinted in humans with monoallelic paternal and maternal expression, respectively. Loss of imprinting (LOI) (i.e., biallelic expression) of IGF2 occurs in some tumors and may promote tumor growth. We examined imprinting of IGF2 and H19 in 6 fetal cerebella, 1 adult cerebellum, 15 medulloblastomas, and 7 medulloblastoma cell lines using polymerase chain reaction (PCR) and reverse transcription-PCR of exonic polymorphisms. Loss of imprinting of IGF2 occurred in 2 out of 3 informative fetal cerebella, 3 out of 7 informative medulloblastomas, and 1 out of 4 informative cell lines. Loss of imprinting of H19 occurred in 0 out of 4 informative fetal cerebella, 0 out of 1 informative adult cerebellum, 4 out of 8 informative medulloblastomas, and 1 out of 4 informative cell lines. The biallelic expression of H19 was only partial in two medulloblastomas, however, with one allele being significantly weaker than the other. Loss of imprinting of IGF2 occurs in medulloblastomas or medulloblastoma cell lines but can also occur in normal fetal cerebellum. Its occurrence in medulloblastomas may therefore reflect the tumors' embryonal nature rather than representing a primary pathogenetic mechanism. Our data also indicate that both genes can be imprinted and expressed independently of each another, both in normal cerebellum and medulloblastomas.

Adult↗
PubMed1996

Gliding motility in slide cultures of Myxococcus xanthus in stable and steep chemical gradients.

A method was devised to construct stable and steep chemical gradients in slide cultures to study the movements of gliding cells. The movement of Myxococcus xanthus individual cells and small swarms was studied in these gradients. There was no response to gradients of Casitone and yeast extract that were previously reported to stimulate a positive chemotactic response with M. xanthus.

Caseins↗
PubMed1996

[The musculus pectoralis major rib flap. Personal experiences with 7 cases].

We present a report of our experience with one-step reconstruction of the mandible after resection in tumor cases using an osteomyo-cutaneous flap. We performed a pectoralis major flap with a segment of the fifth rib, blood supplied by the periosteum. In seven cases we had one pseudoarthrosis. The complications in the donor site were none. We see in the pectoralis major-rib flap an alternative to microsurgical techniques, especially in patients with defects in the horizontal part of the mandible.

Adult↗
PubMed1996

Molecular analysis of the lissencephaly gene 1 (LIS-1) in medulloblastomas.

Although medulloblastoma (MB) represents the most frequent malignant brain tumour in children, the molecular pathogenesis of this tumour is still poorly understood. Microsatellite and RFLP studies have revealed allelic losses on the short arm of chromosome 17 in the region 17p13 in approximately 50% of MBs. A candidate for this putative MB suppressor on chromosome 17p13.3 is the recently cloned LIS-1 gene which codes for a regulatory subunit of the intracellular form of the platelet activating factor (PAF) acetylhydrolase. PAF is involved in signal transduction pathways during cerebral development and in the process of neuronal cell migration and differentiation. In this study, 42 medulloblastomas including seven tumour cell lines and 35 primary tumours were analysed for LIS-1 mRNA expression by RT-PCR and Northern blot analysis. Twenty-four paired blood and MB DNA samples were examined by PCR analysis with a panel of microsatellites located on chromosome 17p to detect loss of heterozygosity (LOH). Finally, the single-strand conformation polymorphism (SSCP) technique and DNA sequencing were employed to detect mutations or small deletions in the coding region of the LIS-1 gene. Of 24 MBs, 13 exhibited loss of heterozygosity on chromosome 17p13.3 for at least one of the microsatellite markers. LIS-1 mRNA expression was detected in all MB tumours and MB cell lines. None of the tumours showed a somatic mutation in the LIS-1 coding region. A novel polymorphism in the 3'UTR of LIS-1 was found in MB patients, but also in healthy control persons. These data indicate that the LIS-1 gene located at 17p13.3 is not involved in the molecular pathogenesis of MBs.

Adolescent↗
PubMed1995

Effectiveness of various sperm processing methods in removing seminal plasma from insemination media.

The effectiveness of the wash and swim-up (1 and 2 wash cycle), two layer Percoll gradient, SpermPrep and underlay sperm preparation methods in removing seminal plasma from insemination suspensions was investigated. The number of wash cycles needed to rid sperm suspensions of seminal plasma (n = 15) was also determined. All sperm preparation methods were compared to the control wash and swim-up method, performed using Earle's buffered salt solution (EBSS), without serum supplementation so as not to mask seminal plasma concentrations. Control processing comprised 1 ml semen subjected to two wash cycles in EBSS followed by a swim-up period of 60 min under 5% CO2 in air. The Percoll method comprised 1 ml semen layered on a discontinuous 36 and 81% Percoll gradient (n = 14). In the SpermPrep method, 1 ml semen was run through a SpermPrep II column (n = 10), and underlay samples (n = 12) were processed by two wash cycles, after which sperm pellets were resuspended in the remaining medium, layered under 1.2 ml EBSS and allowed to swim up under 5% CO2 in air for 1 h. Seminal plasma and supernatant fractions obtained after each processing phase were stored at -20 degrees C and protein concentrations were determined by spectrophotometry. The wash and swim-up method was the most effective in removing seminal plasma from sperm suspensions, followed by the two-layer Percoll gradient, underlay and finally the SpermPrep II processing methods.

Chemical Fractionation↗
PubMed1995

Effect of growth hormone on IGF-I levels in a patient with growth hormone deficiency and Wilson disease.

This is a case report of a boy with a combination of two rare disorders:growth hormone deficiency (GHD) and Wilson disease. To our knowledge, no comparable case has yet been published in the literature. GHD was diagnosed at the age of 4.5 years (height standard deviation score (SDS) -4.85). However, because of a difficult family background, growth hormone (GH) therapy could not be started. The boy was not seen again until the age of 7.7 years (height SDS -4.77), when GHD was reconfirmed and GH therapy could be initiated (dose 0.6 IU/kg/week). At that time, elevated liver enzymes (GPT 128 U/l, GOT 67 U/l, gamma-GT 28 U/l) confused diagnostic procedures. On GH, growth velocity SDS increased from -1.86 to +4.50 in the first year and +3.87 in the second year, and height SDS increased to -4.26 and -3.59. However, serum IGF-I levels did not normalize (max. 67 ng/ml), and liver enzymes were still elevated. At the age of 10 years, Wilson disease was diagnosed in view of low concentration of serum ceruloplasmin, elevated urinary copper excretion and high copper content in a liver biopsy sample. Under a combined therapy with D-penicillamine and GH, serum liver enzymes decreased, and IGF-I levels increased to normal. Height SDS for chronological age has improved constantly.

Ceruloplasmin↗
PubMed1995

Mapping of the spinal muscular atrophy (SMA) gene to a 750-kb interval flanked by two new microsatellites.

The gene for autosomal recessive proximal spinal muscular atrophy (SMA) has recently been mapped between D5S629 and D5S557. We report here a new single-locus microsatellite A31 (D5S823) and two multicopy microsatellites 97T-CA and 95/23-CA. The marker A31 maps to the region of overlap between YACs y116, y55 and y122, distal to D5S629; 97T-CA originates from a cosmid corresponding to the STS 97T, localized distally to A31, while 95/23-CA derives from a cosmid corresponding to the STS 97U, localized proximally to D5S557. We tested all our key recombinant families with these markers. In one type I/II SMA family, a recombinant was found that placed the SMA locus distal to D5S823. Homozygosity mapping in a consanguineous type I SMA family indicates that the SMA gene lies proximal to 95/23-CA. Thus, the two new markers, A31 and 95/23-CA further refine the SMA gene to an approximately 750-kb interval.

Base Sequence↗