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Biomedical subjects

J Koch

Publications and source records attributed to J Koch.

At least 19 recordsLinked to original sources
PubMed1995

Partial triplication (7q) in a child with acute lymphoblastic leukemia demonstrated with conventional cytogenetics, PRINS, and chromosome painting.

In this report we describe a partial triplication (7q) and other structural aberrations found in a child with acute lymphoblastic leukemia (ALL), and we demonstrate the importance of PRimed IN Situ labeling (PRINS) and chromosome painting as a support to banding analysis for the clarification of complex structural chromosome rearrangements. Initially, the der(7) was interpreted as der(7)t(1;7;7). However, PRINS and chromosomes painting showed that der(7) consisted entirely of chromosome 7 material. Further, a derivative chromosome interpreted by banding analysis as a der(17)t(?1;17) was shown to be der(17)t(13;17) by the newly developed PRINS painting technique.

Child↗
PubMed1995

Characterization of a 45-kDa flavoprotein and evidence for a rubredoxin, two proteins that could participate in electron transport from H2 to CO2 in methanogenesis in Methanobacterium thermoautotrophicum.

Methanobacterium thermoautotrophicum strains contain a flavoprotein (flavoprotein A) that copurifies with the H2:heterodisulfide oxidoreductase complex. In this study, we report the iron-dependent synthesis and biochemical properties of flavoprotein A, cloning and sequencing of the flavoprotein-A-encoding gene (fpaA) and the co-transcription of fpaA with two downstream open reading frames, one of which (rdxA) appears to encode a rubredoxin. Native flavoprotein A has been shown to be a homodimer of a 45-kDa polypeptide that contains 1.3 mol FMN/45-kDa subunit but no iron or acid-labile sulfur. Catalytic amounts of the H2:heterodisulfide oxidoreductase complex or of the F420-reducing hydrogenase reduced flavoprotein A with H2, at specific rates of 0.3-0.4 U/mg enzyme, generating up to 70% flavin semiquinone before reduction to the flavin hydroquinone was observed. This intermediate accumulation of the semiquinone species had a kinetic rather than a thermodynamic basis, because the semiquinone form of flavoprotein A, generated by photoreduction, disproportionated quantitatively to the quinone and hydroquinone species. The midpoint potential of the quinone/hydroquinone couple was estimated to be 230 +/- 15 mV, at pH 7.6, versus the normal hydrogen electrode. Quantitation of Western blots demonstrated that flavoprotein A constituted approximately 1.5% of the soluble protein in cells grown in an iron-sufficient medium but that this increased to about 6% of the cellular protein when the iron the medium was depleted. The increase in the flavoprotein A content of cells grown under iron-limiting conditions was mirrored by a decrease in the content of the iron-rich polyferredoxin that also copurified with the H2:heterodisulfide oxidoreductase complex. The fpaA gene, cloned and sequenced from M. thermoautotrophicum strain delta H, encodes 404 amino acids in a sequence that has a C-terminal domain (approximately 130 amino acid residues) with features consistent with a flavodoxin structure. The remainder of flavoprotein A has sequences that are also predicted to be present in the N-terminal region of the orf14 gene product, which also appears to be an enlarged flavodoxin, encoded in the nif region of Rhodobacter capsulatus. Immediately downstream from fpaA, two open reading frames designated orfX and rdxA, have been located and shown by Northern-blot analyses to be co-transcribed with fpaA, although approximately 50% of fpaA-orfX-rdxA transcripts terminated or were cleaved within rdxA. Primer extension studies revealed that transcription of this transcriptional unit (the fpa operon) was initiated 32 nucleotides upstream of fpaA, at a site 25 nucleotides downstream from a sequence consistent with an archaeal TATA-box promoter element.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1995

Functional characterization of novel IL-2 transcriptional inhibitors.

IL-2-mediated T cell proliferation is a critical early event in the inflammatory process. Formation of the NFAT-1 transcriptional complex on the IL-2 promoter is essential for IL-2 transcription. Using a cell line that is stably transfected with a trimer of the NFAT-1 regulatory element linked to a lac-Z reporter gene, we screened for inhibitors of NFAT-1-mediated beta-galactosidase activity. WIN 61058 and WIN 53071 were identified as microM inhibitors. These compounds also inhibited beta-galactosidase mRNA levels. Similar inhibition of NFAT-1-mediated gene expression was observed in a second cell line, which is stably transfected with NFAT-1 regulatory elements linked to the reporter gene for sCD8. At 10 microM, both compounds inhibited IL-2 mRNA and protein levels in the NFAT-1-linked lac-Z transfectants, and in human lymphocytes. Both compounds inhibited the mixed lymphocyte reaction, and this inhibition was reversed by exogenous IL-2. WIN 53071 inhibited IL-2 production induced in the calcium-dependent PMA and ionomycin pathway. Conversely, calcium-independent anti-CD28 Ab and PMA-induced IL-2 production was resistant. Both compounds altered the NFAT-1 transcriptional complex, causing its retarded mobility on gels. By these functional criteria, we believe we have identified two structurally distinct, novel inhibitors of NFAT-1-mediated transcription.

Base Sequence↗
PubMed1995

Simultaneous detection of centromere-specific probes and chromosome painting libraries by a combination of primed in situ labelling and chromosome painting (PRINS-painting).

In situ techniques for the detection of specific chromosomes using centromeric probes and the decoration of entire chromosomes using chromosome painting are well established. However, in the deciphering of complex chromosomal aberrations it is valuable to be able to detect the centromere and the entire DNA of a specific chromosome in different colours simultaneously on the same metaphase. In this report we describe a combination of the primed in situ labelling (PRINS) technique and chromosome painting for simultaneous visualization of centromere-specific oligonucleotides and chromosome painting libraries. A key feature is that the denaturation step in the PRINS reaction is sufficient to keep the chromosomes denatured for chromosome painting. This means that PRINS and consecutive chromosome painting can be performed as a single procedure (PRINS-painting).

Centromere↗
PubMed1995

[Maximal force measurements of lip and tongue pressures and their significance for the diagnosis of orofacial dyskinesias].

The functioning of the orofacial muscular system essentially determines the shape of the jaw and of the dental arch as well as the position of the axis of the anterior teeth. Disturbances of the normal functioning can cause anomalies of the position of teeth or malformations of the bone structure. With the help of the newly developed device "Myometer 160" we now have the possibility to measure the intra- and extraoral forces. We examined 107 persons aged 8 to 37 years. The maximal force was measured by ventral tongue pressure, when the lips were pressed against each other and when a brass button was pulled. In addition clinical results as well as a functional status were ascertained in order to record orofacial dyskinesias. A significant connection between the age respectively the sex of the persons and the determined force was found. However, no clear relationship between the occlusal position respectively the functional anomaly and the results of maximal force was determined. Thus it does not seem sensible to use maximal force measurement within the framework of the determined. Thus it does not seem sensible to use maximal force measurement within the framework of the diagnosis of orofacial dyskinesias.

Adolescent↗
PubMed1995

Translocation (1;16) identified by chromosome painting, and PRimed IN Situ-labeling (PRINS). Report of two cases and review of the cytogenetic literature.

We used the molecular cytogenetic in situ techniques chromosome painting and PRimed IN Situ labeling (PRINS) to elaborate the cytogenetic observations in two cases of the rare aberration der(16)t(1;16), which occurs in a wide variation of hematologic and nonhematologic malignancies [1-3]. Review of the literature showed that, in contrast to the chromosome 1 breakpoint, the breakpoint on chromosome 16 is associated with diagnosis as well as patient age.

Adult↗
PubMed1995

Cleft malformation of lip, alveolus, hard and soft palate, and nose (LAHSN)--a critical view of the terminology, the diagnosis and gradation as a basis for documentation and therapy.

The hope for the improvement of the treatment of patients with a cleft malformation of lip, alveolus, hard and soft palate, and nose (LAHSN) is to review and to compare new concepts and methods. But research in this way presumes an exact, reliable and reproduceable diagnosis and documentation. This article reviews previously published diagnosis and documentation systems, and also suggests a concise and simple system to record a cleft lip and palate diagnosis. The anatomical regions of the cleft are considered as well as their extent. A three way division to record the extent of the malformed regions is proposed. It is a extensively used diagnosis recording system.

Alveolar Process↗
PubMed1995

[The value of clinical and chemical laboratory follow-up parameters in neuroborreliosis].

Whereas the diagnosis of acute neuroborreliosis by considering clinical and cerebrospinal fluid parameters is very reliable chronic neuroborreliosis is an excluding diagnosis. The clinical symptoms are uncharacteristic, and there is no reliable laboratory test permitting a safe diagnosis. Serological evidence of antibodies is no sign of activity of disease. Development of chronic infection after adequate treatment of acute neuroborreliosis seems to be very rare. We reinvestigated 15 patients half a year after antibiotic therapy of acute neuroborreliosis with regard to clinical and laboratory parameters. Most patients had a continuous intrathecal IgG antibody production against Borrelia burgdorferi, whereas no clinical signs of chronic neuroborreliosis existed. The antibody production against Borrelia burgdorferi must not be regarded as a sign of chronic infection.

Adult↗
PubMed1995

Ultrasonographic findings in a basenji with immuno-proliferative enteropathy.

The ultrasonographic findings in a one-and-a-half-year-old female basenji with immunoproliferative enteropathy are described. On ultrasonographic examination, generalised thickening of the small bowel wall was found, ranging between 4 and 6 mm. The normal layered appearance of the intestinal wall was replaced by three distinct layers; an innermost enlarged hyperechogenic layer; an enlarged poor echogenic layer, and an outer hyperechogenic layer. These findings are consistent with the histopathological appearance of this particular chronic inflammatory bowel disease, since the inner layer probably represents the infiltrated mucosa, the middle layer the infiltrated lamina propria and the outer layer the serosa. Thus, the ultrasonographic finding of generalised thickening of the intestinal wall in a basenji presenting with chronic diarrhoea, weight loss, anorexia or vomiting is strongly indicative of immunoproliferative enteropathy.

Animals↗
PubMed1995

Genetic linkage analysis in hereditary non-polyposis colon cancer syndrome.

Hereditary Non-polyposis Colon Cancer Syndrome (HNPCC) is the most common cause of familial colorectal cancer. Molecular genetic studies of HNPCC have shown evidence of locus heterogeneity, and mutations in four genes (hMSH2, hMLH1, hPMS1, and hPMS2) which encode components of the mismatch enzyme repair system may cause HNPCC. To determine the extent and nature of locus heterogeneity in HNPCC, we performed genetic linkage studies in 14 HNPCC families from eastern and north-western England. Linkage to hMLH1 was excluded in six families, each of which were likely to be linked to hMSH2 (lod score > 1.0 in each family and total lod score for all six families = 7.64). Linkage to hMSH2 was excluded in three families, each of which were likely to be linked to hMLH1 (lod score > 1.0 in each family and total lod score at hMLH1 for all three families = 3.93). In the remaining five families linkage to hMSH2 or hMLH1 could not be excluded. These results confirm locus heterogeneity in HNPCC and suggest that, in the population studied, most large families with HNPCC will have mutations in hMSH2 or hMLH1. We did not detect any correlation between clinical phenotype and the genetic linkage results, but a Muir-Torre syndrome family excluded from linkage to hMLH1 was likely to be linked to hMSH2 and showed microsatellite instability in a tumour from an affected relative.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Staining of human telomeres with primed in situ labeling (PRINS).

As described, the PRINS method is a very rapid and reliable way of staining human telomeres. To obtain the maximum frequency of stained telomeres, the primer (CCCTAA)7 should be used, although the average frequency never quite reaches 100%. The frequency is strongly dependent on the age of the individual, being significantly higher in children and newborns than in adults. A difference between the (CCCTAA)7 primer and the complementary primer is demonstrated and a possible explanation is proposed, namely, that gaps in the C-rich strand cause chain elongation termination after the addition of only one dTTP molecule.

Adult↗
PubMed1995

Construction of a panel of chromosome-specific oligonucleotide probes (PRINS-primers) useful for the identification of individual human chromosomes in situ.

We present the sequences of a set of oligonucleotides that, when used as primers for PRimed IN Situ (PRINS) labeling, are diagnostic for repetitive sequences in specific human chromosomes. Combined, they enable identification of all human chromosomes except 6, 19, and 20. However, as is also the case with cloned centromeric hybridization probes, chromosomes 14 and 22 are stained together. Along with the sequences of these oligonucleotides we offer a simple, universal procedures for their use. We also present an oligonucleotide that binds to both strands of alpha-satellite DNA, making it possible to specifically amplify alpha-satellite DNA by PCR with this one oligonucleotide alone as primer. The origin of the alpha-satellite DNA in the starting material (whether somatic cell hybrids, flow-sorted chromosomes, or microdissected material) can then be determined on test metaphase spreads by in situ hybridization or PRINS with the PCR product.

Base Sequence↗
PubMed1995

BNP plasma levels during acute volume expansion and chronic sodium loading in normal men.

Since the isolation of porcine brain natriuretic peptide (pBNP) in 1988, many aspects of this new endocrine and paracrine system have been elucidated. However, the precise role of human BNP (hBNP) in the regulation of sodium balance and blood pressure in men is still unclarified. We investigated the impact of acute volume expansion and high sodium intake on ANP and BNP plasma levels of 21 healthy male subjects. Following acute infusion of 2000 ml 0.9% saline into a peripheral vein over 30 minutes in a lying position, ANP levels in plasma increased from 110 +/- 14 pg/ml to 199 +/- 18 pg/ml (p < 0.001), while BNP levels remained constant (26 +/- 3 pg/ml before, 28 +/- 3 pg/ml after volume expansion). In a second experiment we investigated the change of ANP and BNP plasma levels after five days of controlled sodium intake (Here blood tests were taken from the probands in an upright position). ANP levels averaged 42 +/- 5 pg/ml after low and 73 +/- 14 pg/ml after high sodium intake. Before starting the diet, the ANP fasting blood level was 56 +/- 6 pg/ml. During both diets, plasma BNP was not altered significantly, but we found a slight insignificant increase after high sodium intake. At the end of each diet we tested ANP and BNP secretion by a physical exercise in an upright position. After high salt intake, BNP plasma levels rose from 32 +/- 4 pg/ml at rest to 45 +/- 7 pg/ml (p < 0.025) after 15 minutes of exercise, while ANP rose from 73 +/- 14 pg/ml to 120 +/- 20 pg/ml (p < 0.001). These results suggest a different regulation of ANP and BNP in normal subjects. ANP secretion is modulated by volume loading and by low or high salt intake while BNP responses to physical exercise.

Adult↗
PubMed1995

Long-term follow-up of endoscopic treatment for bleeding gastric and duodenal ulcers.

OBJECTIVE: To examine the long-term consequences of endoscopic therapy for bleeding peptic ulcers. METHODS: Eighty-seven consecutive patients who underwent endoscopic treatment for bleeding gastric ulcer (GU) and/or duodenal ulcer (DU) over a 42-month period were identified. Long-term follow-up was available for 76 (mean, 495 days; SEM, 45 days). Therapy consisted of epinephrine injection, heater probe use, or both. Recurrent hemorrhage only at the primary treatment site was considered. RESULTS: The sites of hemorrhage were GU (40 patients), DU (34 patients), and both (2 patients). Emergent surgery was required in two GU patients for whom endoscopic treatment was ineffective. Recurrent hemorrhage ultimately occurred in 33% of patients--40% of GU and 25% of DU patients. Surgical therapy was eventually required in 26% of patients after endoscopic hemostasis and was more frequent in patients with recurrent hemorrhage from DU than GU (78% vs 56%). For those patients who re-bled within 8 days of the index endoscopy, 82% required surgery, compared with 33% of patients who re-bled more than 8 days after the index endoscopy (p = 0.03). CONCLUSIONS: The rate of recurrent hemorrhage after endoscopic hemostasis for bleeding GU and DU was 33% in our long-term follow-up. After endoscopic hemostasis, surgery was eventually required in 24% of all patients and in 64% of patients who had recurrent hemorrhage. Patients who had recurrent hemorrhage more than 1 wk after initial endoscopic hemostasis were effectively treated by repeated endoscopic therapy and were significantly less likely to require surgery than patients who re-bled within 1 wk.

Duodenal Ulcer↗
PubMed1994

Effects of a low sodium diet with a high potassium content on plasma endothelin-1, atrial natriuretic peptide and arginine vasopressin in normal dogs.

Eight clinically healthy male beagle dogs received a low sodium diet for 5 weeks. Before and after this period the dogs received a control diet for 3 weeks. Both diets provided the dogs with approximately 6.8 mmol K+/kg/day. Neither introducing nor withdrawing the low sodium diet changed the plasma concentrations of endothelin-1 (ET-1), atrial natriuretic peptide (ANP) and arginine vasopressin (AVP). Pooled data from the control periods were not different from the low sodium period for either ET-1 (2.31 pg/ml and 2.09 pg/ml, P = 0.21), ANP (42.51 pg/ml and 38.99 pg/ml, P = 0.44) or AVP (4.14 pg/ml and 4.16 pg/ml, P = 0.91). It was concluded that ET-1, ANP and AVP in normal dogs are unaffected by a 6-fold change in sodium intake in the presence of a high potassium intake.

Animals↗
PubMed1994

Estimates of components of variance of the rectal temperature in clinically healthy dogs in a hospital environment.

The rectal temperature is frequently measured in the morning on a daily basis in hospitalized dogs. Besides comparing the measured temperature to a population-based reference interval, it may also be of interest to evaluate the differences between consecutive measurements in order to follow the health status of a particular dog. In veterinary clinical chemistry, a parameter referred to as the critical difference, which can be used to judge if the difference between two consecutive measurements may be safely ascribed to random variation or not, has recently been introduced. The purpose of the present study was to obtain an estimate of the critical difference of the rectal temperature based on measurements of the rectal temperature in clinically healthy dogs in a hospital environment. The rectal temperature was measured in a standardized manner on 6 different days in 7 dogs. The total variance was estimated as 0.1015. The inter-individual variance was 0.0428, and the intra-analytical variance including the analytical variance was 0.0587. From these components of variance, the critical difference was calculated as 0.69 degrees C. Thus, the rectal temperature measured in the morning in hospitalized dogs can be expected to fluctuate about 0.7 degrees C from day to day due to random variation alone.

Analysis of Variance↗