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Biomedical subjects

J Koch

Publications and source records attributed to J Koch.

At least 55 records · Page 3Linked to original sources

Malformation of the vomer in submucous cleft palate.

BACKGROUND: Several criteria are described in the literature to diagnose a submucous cleft palate. Commonly the differences in the extent of the submucous cleft will not be as overt as in open clefts. Nevertheless, complete submucous cleft palate may cause imperfect palato-pharyngeal closure so that the affected person needs to undergo speech training and surgical treatment. PATIENTS: We investigated 30 patients who underwent palatal repair to correct this disorder. They were evaluated according to the Koch's documentation system. RESULTS: In all patients an additional malformation of the inner nose was found: The vomer was not fused with the palatal shelves. There were different degrees of severity of this vomerine malformation and they were not necessarily correlated with the extent of the palatal cleft. CONCLUSION: In our opinion, this malformation of the vomer should be seen as a typical symptom of classical submucous cleft palate. Discussion is needed on how the vomerine malformation should be incorporated into the surgical procedure. Since we know from septal surgery that a basal septal perforation will lead to disturbances of nasal breathing.

Adolescent↗

[Measuring blood pressure at the upper arm and wrist: are there differences?].

Reliability and accuracy of a wrist and an upper arm sphygmomanometer were compared. Only in one of 27 persons were measurements at the wrist impossible. The 26 remaining volunteers showed good agreement between arm and wrist measurement (118/71 and 118/69 mmHg respectively). The variance was expectedly larger for systolic than diastolic values (10 vs 8 mmHg). As expected the correlation between the two methods was high (0.83 for systolic, 0.75 for diastolic values). Reproducibility of measurements was also equivalent for both methods. Devices for blood pressure measurements at the wrist are thus suitable. In order to identify individuals in which measurements at the wrist are impossible for technical reasons comparative measurements on the upper arm should precede the recommendation for a wrist device.

Adolescent↗

Neocentromeres and alpha satellite: a proposed structural code for functional human centromere DNA.

A comparative analysis of the conserved region of primate alpha satellite DNA and of a human neocentromere is reported. The two types of centromere DNA share structural features, possibly defining mitotically functional human centromere DNA. These features consist of double dyad symmetries of a particular size, as well as short conserved base motifs adjacent to the dyad symmetries. The possible importance of these features is supported by their presence also in the centromeres of yeast. The overall resemblance between primate alpha satellite DNA and yeast centromere DNA is further strengthened by the presence of a second shared structure. This structure consists of a single dyad symmetry incorporating a particular short base sequence. In the mitotically stable human neocentromere, this second symmetry is not found in connection with the double symmetry. However, the yeast homologue of the second symmetry is responsible for stability in meiosis I, rather than for mitotic stability. If the human homolog serves a similar function, it would be expendable, except for reproduction.

Animals↗

A frameshift mutation in prominin (mouse)-like 1 causes human retinal degeneration.

The disks of vertebrate photoreceptors are produced by outgrowths of the plasma membrane. Hence genes that encode retinal proteins targeted to plasma membrane protrusions represent candidates for inherited retinal degenerations. One such candidate is the gene encoding human prominin (mouse)-like 1 (PROML1, previously known as AC133 antigen) which belongs to the prominin family of 5-transmembrane domain proteins. Murine prominin (prom) shows a strong preference for plasma membrane protrusions in a variety of epithelial cells whereas PROML1 is expressed in retinoblastoma cell lines and adult retina. In the present study, molecular genetic analyses of a pedigree segregating for autosomal recessive retinal degeneration indicated that the affected individuals were homozygous for a nucleotide 1878 deletion in PROML1. This alteration is predicted to result in a frameshift at codon 614 with premature termination of translation. Expression of a similar prom deletion mutant in CHO cells indicated that the truncated protein does not reach the cell surface. Immunocytochemistry revealed that prom is concentrated in the plasma membrane evaginations at the base of the outer segments of rod photoreceptors. These findings suggest that loss of prominin causes retinal degeneration, possibly because of impaired generation of the evaginations and/or impaired conversion of the evaginations to disks.

AC133 Antigen↗

Cinematic nuclear scintigraphy reliably directs surgical intervention for patients with gastrointestinal bleeding.

HYPOTHESIS: Cinematic technetium Tc 99m red blood cell ((99m)Tc-RBC) scans, in which real-time scanning is performed and analyzed, can accurately localize gastrointestinal bleeding and thus direct selective surgical intervention. DESIGN: Retrospective medical record review with historical controls. SETTING: Large, university-affiliated public hospital in urban setting. PATIENTS: Twenty-six patients presenting with upper and lower gastrointestinal hemorrhage who underwent cinematic (99m)Tc-RBC scan examinations between 1990 and 1997 and required surgical intervention to control the bleeding. INTERVENTIONS: All patients with gastrointestinal bleeding underwent open surgical procedures to provide cessation of bleeding and resection of appropriate abnormalities. MAIN OUTCOME MEASURES: Patient outcome was based on correlation between preoperative RBC scans and intraoperative findings, surgical pathology, and postoperative clinical course. RESULTS: Twenty-five (96%) of 26 scans were interpreted as positive for gastrointestinal bleeding. In 22 of these 25 scans, the site of bleeding was correctly identified for a sensitivity of 88%. One or more additional diagnostic tests were performed on 19 (73%) of 26 patients, and included angiography and flexible endoscopy. The most common operation performed to control bleeding was a hemicolectomy (14/26). Diverticulosis was the most prevalent diagnosis (46%). Two patients (8%) experienced rebleeding after operation. The overall mortality rate was 19% (5/26). CONCLUSIONS: Cinematic (99m)Tc-RBC scintigraphy is a sensitive, noninvasive alternative to mesenteric angiography for accurately localizing the site of gastrointestinal hemorrhages. As such, this technique can be reliably used to direct selective surgical intervention.

Adult↗

[Establishment of a national database for ICU-associated infections. First results from the "Krankenhaus-Infections-Surveillance-System" (KISS)].

OBJECTIVES: To establish a surveillance system as an element of internal quality management, participating intensive care units (ICUs) report their ICU-associated infection surveillance data for aggregation into a national database. METHODS: In order to provide data on ICU-associated infections, a nosocomial surveillance system in German intensive care units (Krankenhaus-Infections-Surveillance-System (KISS)) started in 1997. The method of data collection is based on the (adult) ICU surveillance component from the National Nosocomial Infections Surveillance (NNIS)-System. Until now 113 German ICUs (most of them medical/surgical ICUs) were included in this system. We continuously collected and calculated the data from site-specific infections (device-associated pneumonias, blood stream infections and urinary tract infections). RESULTS: There are now a total of 393,177 patient-days (100,015 patients) among them 176,415 ventilator-days, 295,221 central line-days and 316,799 urinary catheter-days in the data base. The data analysis showed the following device-associated infection rates: 11.2 pneumonias/1000 ventilator-days, 1.8 primary bloodstream infections/1000 central line-days and 4.0 urinary tract infections/1000 urinary catheter-days. CONCLUSION: The project has reached high interest in Germany and animated more ICUs to take part or to apply the same method in order to use the reference data for comparison.

Cross Infection↗

Accuracy of endoscopic databases for assessing patient symptoms: comparison with self-reported questionnaires in patients infected with the human immunodeficiency virus.

BACKGROUND: Endoscopic databases are increasingly used for clinical research, but their validity as research instruments has not been assessed. We compared the accuracy of endoscopic indications recorded in an endoscopic database with patient symptom questionnaires. METHODS: All patients infected with the human immunodeficiency virus referred to the outpatient gastroenterology practice were prospectively evaluated using recognized symptom questionnaires. For patients undergoing esophagogastroduodenoscopy, the procedure indications recorded in the endoscopic database and the patient's self-reported symptom scores were compared. RESULTS: Ninety-three patients were evaluated. The symptoms of nausea/vomiting, diarrhea, and anorexia were highly predictive for the presence of these symptoms on the patient questionnaires. The symptoms of dyspepsia/abdominal pain did not predict well the presence of these symptoms on the questionnaire. Patients reported frequent and severe symptoms that were not recorded as indications for the procedures. The overall agreement (kappa statistic) was highly variable, from slight (kappa = 0.07 for anorexia) to moderate (kappa = 0.44 for diarrhea). CONCLUSIONS: Endoscopic indications are variably associated with self-reported symptom scores. These findings raise concerns about using some endoscopic database indications as accurate representations of patients' symptoms. Until performance characteristics of a given database are known, symptom-oriented research should use validated questionnaires whenever possible.

Databases, Factual↗

Electrodiagnostic reference values for the lateral antebrachial cutaneous nerve: standardization of a 10-cm distance.

OBJECTIVE: To derive a normative database for nerve conduction values of the lateral antebrachial cutaneous nerve (LACN) using a large and varied subject population. DESIGN: Descriptive study. SETTING: Private office or university-based clinic. PARTICIPANTS: Volunteers (n = 213), recruited through advertisements, who met inclusion criteria. MAIN OUTCOME MEASURES: Onset latency, peak latency, baseline-to-peak amplitude, peak-to-peak amplitude, area, rise time, duration, side-to-side differences, and the effects of age, race, sex, height, and body mass index (BMI) were investigated on 213 healthy volunteers between the ages of 19 and 79 years. RESULTS: The mean +/- SD onset latency was 1.7+/-0.2 ms. The 95th and 97th percentile values for onset latency were 2 and 2.1 ms, respectively. Mean peak latency was 2.2+/-0.2 ms. Both the 95th and 97th percentile values for peak latency were 2.5 ms. Mean onset to peak amplitude was 18+/-10 microV. The 5th and 3rd percentile values for onset to peak amplitude were 6 and 5 microV, respectively. Mean peak-to-peak amplitude was 22+/-15 microV. The 5th and 3rd percentile values for peak-to-peak amplitude were 7 and 6 microV, respectively. Mean area was 11+/-7nV-s, mean rise time was 0.5+/-0.1 ms, and mean duration was 1.1+/-0.2 ms. Mean side-to-side difference was 0.1+/-0.2 ms for onset latency, 0.1+/-0.2 ms for peak latency, 1+/-12 microV for onset to peak amplitude, and 0+/-17 microV for peak-to-peak amplitude. Increasing age and BMI were associated with lower mean amplitudes, but did not affect the lower limits of normal. CONCLUSION: These normative values will be useful in electrodiagnostic study of the LACN.

Adult↗

Characterization of three hairy cell leukemia- derived cell lines (ESKOL, JOK-1, and hair-M) by multiplex-FISH, comparative genomic hybridization, FISH, PRINS, and dideoxyPRINS.

Hairy cell leukemia (HCL) is a chronic B-lymphocyte leukemia. Due to the proliferative inertia of the malignant cells, HCL-derived cell lines are an important tool for studies on this disease. We have elaborated the karyotypes of three HCL-derived cell lines, ESKOL, JOK-1, and Hair-M, by combining a range of molecular cytogenetic techniques, including multiplex (multicolor) fluorescence in situ hybridization (M-FISH), comparative genomic hybridization (CGH), conventional FISH, primed in situ labeling (PRINS), and dideoxyPRINS. We found ESKOL to be monoclonal with a single chromosome aberration, der(7)t(3;7)(q26.3;q31). JOK-1 also appeared to be monoclonal, having the karyotype 48,XY,der(4) t(1;4)(1pter-->p32::4qter-->pter), der(6)(6qter-->p22::q12--> qter), +der(7)t(7;11)(7pter-->q21::11p15-->pter),der(8)t(5;8;12) (5pter-->p14::12p11.2-->p12::8q12-->q21::8?cen-->-->24 .?2), der(14)t(8;14)(8qter-->q24.?2::14q32.3-->pter),+20. These karyotypes differ from the original descriptions of ESKOL and JOK-1. The Hair-M cells analyzed by us were found to be peritetraploid with numerous chromosomal rearrangements. The cell line was also found to be multiclonal. On this basis, we do not regard the Hair-M cell line to be suitable for HCL studies.

Aged↗

Chlorine analysis by diode laser atomic absorption spectrometry.

The general characteristics of Diode Laser Absorption Spectrometry (DLAAS) in low pressure plasmas particularly with respect to the detection of non-metals are comprehensively recapitulated and discussed. Furthermore, a detector, which is based on DLAAS in a microwave-induced low pressure plasma as an alternative technique for halogene-specific analysis of volatile compounds and polymeric matrices is described. The analytical capability of the technique is demonstrated on the chlorine-specific analysis of ablated polymer fragments as well as gas chromatographically separated hydrocarbons. Since the measurements were carried out by means of a balanced-heterodyne detection scheme, different technical noise contributions, such as laser excess and RAM noise could efficiently be suppressed and the registered absorption was limited only by the principal shot noise. Thus, in the case of the polymer analysis a chlorine-specific absolute detection limit of 10 pg could be achieved. Furthermore, fundamental investigations concerning the influence of hydrocarbons on the dissociation capability of the microwave induced plasma were performed. For this purpose, the carbon-, chlorine- and hydrogen-specific stoichiometry of the compounds were empirically determined. Deviations from the expected proportions were found to be insignificant, implying the possibility of internal standardization relative to the response of a reference sample.

Chlorine↗

The human acid ceramidase gene (ASAH): structure, chromosomal location, mutation analysis, and expression.

Acid ceramidase (AC) is the lysosomal enzyme that degrades ceramide into sphingosine and fatty acid. A deficiency in human AC activity leads to the lysosomal storage disorder, Farber disease (FD). The human AC gene (HGMW-approved symbol ASAH) was cloned and characterized, revealing an organization similar to that of the murine AC gene. The human gene spans about 30 kb in length and contains 14 exons ranging in size from 46 to 1201 bp. The exon/intron junctions were determined and found to follow the GT-AG rule. The putative promoter region had a GC content over 60%, lacked a TATA box, and contained several sequences matching transcription factor binding sites, including nine SP-1 sites, one AP-1 site, and three CACC boxes. The promoter activity of a 475-bp fragment from within this region was demonstrated by chloramphenicol acyltransferase assays. Northern blotting revealed variable expression of the human AC RNA; i.e., expression of the major 2.4-kb transcript was high in heart and kidney, followed by lung and placenta, but low in pancreas, liver, brain, and skeletal muscle. Two minor AC transcripts of 1.7 and 1.2 kb also were detected in heart and skeletal muscle. The human AC gene was mapped to the chromosomal region 8p21.3-p22 by in situ hybridization and FISH analyses, syntenic with the mouse chromosomal location. Finally, three new missense mutations, E138V, R254G, and P362R, were identified in the human AC gene from FD patients. Mutant AC cDNAs containing these point mutations were constructed and examined using the FLAG-tagged expression system. Although the levels of protein expression for these mutant ACs were about equivalent to that of the controls, their enzymatic activity was markedly reduced, confirming their authenticity.

3T3 Cells↗

Purification and catalytic properties of Ech hydrogenase from Methanosarcina barkeri.

Methanosarcina barkeri has recently been shown to produce a multisubunit membrane-bound [NiFe] hydrogenase designated Ech (Escherichia coli hydrogenase 3) hydrogenase. In the present study Ech hydrogenase was purified to apparent homogeneity in a high yield. The enzyme preparation obtained only contained the six polypeptides which had previously been shown to be encoded by the ech operon. The purified enzyme was found to contain 0.9 mol of Ni, 11.3 mol of nonheme-iron and 10.8 mol of acid-labile sulfur per mol of enzyme. Using the purified enzyme the kinetic parameters were determined. The enzyme catalyzed the H2 dependent reduction of a M. barkeri 2[4Fe-4S] ferredoxin with a specific activity of 50 U x mg protein-1 at pH 7.0 and exhibited an apparent Km for the ferredoxin of 1 microM. The enzyme also catalyzed hydrogen formation with the reduced ferredoxin as electron donor at a rate of 90 U x mg protein-1 at pH 7.0. The apparent Km for the reduced ferredoxin was 7.5 microM. Reduction or oxidation of the ferredoxin proceeded at similar rates as the reduction or oxidation of oxidized or reduced methylviologen, respectively. The apparent Km for H2 was 5 microM. The kinetic data strongly indicate that the ferredoxin is the physiological electron donor or acceptor of Ech hydrogenase. Ech hydrogenase amounts to about 3% of the total cell protein in acetate-grown, methanol-grown or H2/CO2-grown cells of M. barkeri, as calculated from quantitative Western blot experiments. The function of Ech hydrogenase is ascribed to ferredoxin-linked H2 production coupled to the oxidation of the carbonyl-group of acetyl-CoA to CO2 during growth on acetate, and to ferredoxin-linked H2 uptake coupled to the reduction of CO2 to the redox state of CO during growth on H2/CO2 or methanol.

Acetate-CoA Ligase↗

[Incidence of benign prostatic hyperplasia and hepatic cirrhosis].

We studied the incidence of benign hyperplasia of the prostate and hepatic cirrhosis in an ambulatory cohort. Undisturbed androgen production is one of the prerequisites for the development of benign prostatic hyperplasia. The disturbed metabolic activity of the cirrhotic liver causes often hypoandrogenism. Therefore a decreased incidence of prostatic hyperplasia is expected for patients with cirrhosis. All male patients of european origin over 40 newly admitted for treatment at the medical outpatient clinic in Zürich during a period of 6 months were enrolled. From a cohort of 2038 males over 40 a benign prostatic hyperplasia was diagnosed in 124. Nine had cirrhosis of the liver. In 6 patients cirrhosis was found in addition to benign prostatic hyperplasia. The study also confirmed an increased incidence of benign prostatic hyperplasia with age. The incidence of cirrhosis, however, decreased with age in our study, probably as a consequence of reduced life expectancy of the cirrhotic patient. The combined incidence of benign prostatic hyperplasia and hepatic cirrhosis became less common with age than benign prostatic hyperplasia alone. This corresponded to our expectations. This collection of epidemiologic data on benign prostatic hyperplasia and hepatic cirrhosis disclosed several difficulties that should be considered for future studies.

Adult↗

Replication of subgenomic hepatitis C virus RNAs in a hepatoma cell line.

An estimated 170 million persons worldwide are infected with hepatitis C virus (HCV), a major cause of chronic liver disease. Despite increasing knowledge of genome structure and individual viral proteins, studies on virus replication and pathogenesis have been hampered by the lack of reliable and efficient cell culture systems. A full-length consensus genome was cloned from viral RNA isolated from an infected human liver and used to construct subgenomic selectable replicons. Upon transfection into a human hepatoma cell line, these RNAs were found to replicate to high levels, permitting metabolic radiolabeling of viral RNA and proteins. This work defines the structure of HCV replicons functional in cell culture and provides the basis for a long-sought cellular system that should allow detailed molecular studies of HCV and the development of antiviral drugs.

Carcinoma, Hepatocellular↗

An in situ study of variant telomeric repeats in human chromosomes.

Variant telomeric repeats are selectively detected in human telomeres in situ by the novel approach of dideoxy-PRINS, displaying their organization in a format where all the individual chromosome ends can be viewed individually and simultaneously. All human chromosome ends are found to contain variant repeats, though not all types of repeats can be detected on all chromosome ends. Although the staining frequency at particular chromosome ends seems polymorphic among individuals, some chromosome ends are more commonly stained with a given probe than others. A few chromosome ends also appear with particularly strong signals. With a probe for one type of variant repeat ((AGGGTG)n), peculiar patterns with more than two signals per chromosome end are observed.

Humans↗