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Biomedical subjects

J Koch

Publications and source records attributed to J Koch.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Prevalence of hypotension and symptomatic, orthostatic dysregulation in a patient sample of a medical polyclinic].

Orthostatic regulation and prevalence of symptomatic cardiovascular dysregulation was investigated in 200 patients at the outpatient clinic of the University of Zürich. Prevalence of correlations with age, diseases, medication and anamnestic data were analyzed separately. Our data show, that orthostatic drop of blood pressure suspected by anamnestic data can only rarely be verified by standardized orthostatic tests. An orthostatic dysregulation may occur without any symptoms whereas a regularly regulated orthostatic reaction may induce complaints. In analogy to earlier investigations low blood pressure values at rest (< 100/60) proved useless as indicators for orthostatic dysregulation: none of our patients showed low blood pressure values at rest, however, in 15% of them a regulation disorder was proven by symptomatic systolic blood pressure decrease. Mean prevalence of symptomatic orthostatic hypotension was 15.5%, in older patients of both sexes (> 60 years) 19%, in younger patients (< 40) 12%. As expected prevalence of diseases like diabetes (24%) and gastroenterologic disorders (24.1%) was particularly high. Vasoactive medication, on the contrary, had only low impact in this study. Only patients treated with ACE-inhibitors in combination with other antihypertensive drugs showed elevated tendency to symptomatic, orthostatic dysregulation. Orthostatic tests revealed symptomatic and pathologic results in 22.5% of patients with anamnestic symptoms of orthostatic disorder. Only 2.8 patients without any anamnestic hint had a similar positive response. So far none of the proposed criteria for diagnosis of symptomatic orthostatic hypotension has been generally accepted. This study showed that orthostatic complaints could be validated by the reaction of blood pressure and pulse rate in the orthostatic test. A blood pressure drop of more than 15 mmHg may lead to orthostatic complaints irrespective of the blood pressure at rest. Thus, in medical practise the orthostatic test is more useful than the blood pressure at rest.

Adult↗
PubMed1999

Osmotic shrinkage activates nonselective cation (NSC) channels in various cell types.

Osmotic cell shrinkage activates a nonselective cation (NSC) channel in M-1 mouse cortical collecting duct cells (Volk, Frömter & Korbmacher, 1995, Proc. Natl. Acad. Sci. USA 92: 8478-8482). To see whether shrinkage-activated NSC channels are an ubiquitous phenomenon, we tested the effect of hypertonic extracellular solution on whole-cell currents of HT29 human colon carcinoma cells, BSC-1 renal epithelial cells, A10 vascular smooth muscle cells, and Neuro-2a neuroblastoma cells. Addition of 100 mm sucrose to an isotonic NaCl bath solution induced cell shrinkage of HT29 cells as evidenced by a decrease in cell diameter from 18 +/- 1 microm to 12 +/- 1 microm (n = 13). Upon cell shrinkage whole-cell currents of HT29 cells increased within 8 +/- 1 min by about 30-fold (n = 13). Cell shrinkage and current activation were reversible upon return to isotonic solution. Replacement of bath Na+ by K+ or Li+ had almost no effect on the stimulated inward current. In contrast, replacement by N-methyl-d-glucamine (NMDG) completely abolished it and shifted the reversal potential from -4.5 +/- 0.7 mV to -57 +/- 4.1 mV (n = 10). Thus, the stimulated conductance is nonselective for alkali cations but highly selective for cations over anions with a cation-to-anion permeability ratio of about 13. Flufenamic acid (100 microm) inhibited the stimulated current by 84 +/- 4.7% (n = 8). During the early phase of hypertonic stimulation single-channel transitions could be detected in whole-cell current recordings, and a gradual activation of 12 and more individual channels with a single-channel conductance of 17.6 +/- 0.9 pS (n = 4) could be resolved. In analogous experiments similar shrinkage-activated NSC channels were also observed in BSC-1 renal epithelial cells, A10 vascular smooth muscle cells, and Neuro-2a neuroblastoma cells. These findings indicate that shrinkage-activated NSC channels are an ubiquitous phenomenon and may play a role in volume regulation.

Animals↗
PubMed1999

Kinetic parameters and tissue distribution of 5-oxo-L-prolinase determined by a fluorimetric assay.

5-Oxo-L-prolinase (5-OPase) catalyses the hydrolysis of 5-oxo-L-proline to glutamate with concomitant stoichiometric cleavage of ATP to ADP, a reaction which is known to be part of the gamma-glutamyl cycle-an interrelated series of reactions involved in the synthesis and metabolism of glutathione. As recent studies indicate, this cyclic pathway plays a crucial role in the regulation of amino acid transport. Apparently, the intermediate product 5-oxo-L-proline functions as a second messenger molecule that upregulates the activity of certain amino acid transport systems. Thus, the degradation of 5-oxo-L-proline by 5-OPase leads to the downregulation of this stimulus. In this study, a new sensitive fluorimetric assay for 5-OPase activity was established which is based on the derivatization of glutamate with o-phthaldialdehyde in the presence of thiols and subsequent separation of the products by HPLC. The method is suitable for the screening of chromatography fractions as well as for the determination of the kinetic parameters Km and Vmax of purified 5-OPase. Additionally, it can be used for the measurement of enzyme activity in crude cell extracts and evaluation of tissue distribution.

Amidohydrolases↗
PubMed1999

Race effect on nerve conduction studies: a comparison between 50 blacks and 50 whites.

OBJECTIVE: To determine whether there are any differences in nerve conduction study results between blacks and whites. DESIGN: The following studies were performed: median, ulnar, peroneal, and tibial motor studies; median and ulnar mixed motor/sensory studies; sural and radial sensory studies; and H-reflex studies. SETTING: Private office or university-based clinic. PARTICIPANTS: Fifty adult blacks and 50 adult whites who met inclusion criteria, recruited through advertisements. MAIN OUTCOME MEASURES: Differences between blacks and whites were compared to determine whether they exceeded a cutoff of 0.2 msec for latencies, 20% difference for amplitudes, 5 m/sec for conduction velocity, and 1.2 msec for H-reflex times. A repeated analysis of variance was performed to detect statistically significant differences (defined as p< or =.01). RESULTS: Only values for the mean peroneal and tibial motor latencies exceeded the cutoff times. The mean peroneal response was faster by 0.3 msec and the mean tibial response was slower by 0.3 msec in blacks than whites. These differences were not statistically significant at a level of p< or =.01. CONCLUSION: There is no significant difference between blacks and whites in normal nerve conduction study findings in healthy adults.

Adult↗
PubMed1999

A novel approach to ring-type foreign body removal: the "U-wire".

BACKGROUND: Foreign body ingestions are common, especially in pediatric, edentulous, psychiatric, and incarcerated populations. For the 20% of foreign bodies that do not pass spontaneously through the gastrointestinal tract, removal using modern, flexible endoscopes has become routine. METHODS: We describe the successful endoscopic removal of a ring-type or "closed loop" foreign body by means of a novel technique. Utilizing a nasogastric tube inserted alongside the endoscope, a guidewire inserted through the tube is directed through the ring with a "rat-tooth" grasping forceps passed through the accessory channel of the endoscope. The wire is snared and pulled up through the endoscope creating a "U," with both ends of the wire outside of the patient. The nasogastric tube, endoscope, and foreign body may then be removed safely. RESULTS: The technique was easy to perform and the foreign body was removed without complication. CONCLUSIONS: Using the U-wire technique, ring-type foreign bodies may be readily and safely removed.

Adult↗
PubMed1999

The pathology of the velopharyngeal musculature in cleft palates.

AIMS: This article draws attention to a pathological finding in the cleft palate condition that has not been previously described: It is demonstrated that the palatal aponeurosis exists even in cleft palates, but it is disrupted, malpositioned and folded in 2 layers. It is possible to dissect the 2 layers and to unfold the aponeurosis to form a tough tendinous plane. Thus, the retropositioning of the levator veli palatini muscle sling is facilitated. CONCLUSION: For a normal reconstruction of the cleft palate it is not only necessary to reconstruct the levator veli palatini muscle sling but also to approximate and to suture the fibres of the palatal aponeurosis to the corresponding fibres of the opposite side after unfolding them in a mediodorso-cranial direction. In this manner a continuous palatal aponeurosis can be created and subsequently it can serve as a transmitter of the muscle forces.

Cleft Palate↗
PubMed1999

Molecular cytogenetics investigation of the telomeres in a case of Philadelphia positive B-ALL with a single telomere expansion.

We have investigated a single telomere expansion in a case of acute lymphoblastic B-cell leukemia (B-ALL), where half of the cells in the bone marrow sample appeared with a Philadelphia chromosome. Comparing telomere sizes in Philadelphia-positive versus -negative cells, we found generally shorter telomeres in the Philadelphia-positive cells, but with an expansion of the telomere on the long arm of one chromosome 11 homologue. This expansion was also found in a minority of Philadelphia-negative cells. The telomeres in these cells were of the same overall size as the telomeres in the Philadelphia-negative cells without the 11q expansion. Together, these findings suggest that the order of events was: 11q telomere expansion, Philadelphia translocation, overall telomere shortening. The expanded 11q telomere contained the standard telomeric (AGGGTT)(n) repeat, but also variant repeat sequences. The single telomere expansion suggests a non-telomerase mechanism behind the expansion which may also explain the presence of variant repeats in the expanded telomere. The present case illustrates that telomere changes may occur at only some chromosome ends in a subset of cells. To reveal such changes, telomere morphology should be studied with in situ methodology.

Adult↗
PubMed1999

A prospective study of endoscopy in HIV-associated diarrhea.

OBJECTIVE: Diarrhea commonly occurs in persons with human immunodeficiency virus (HIV) infection. The optimal use of endoscopic procedures remains poorly studied for patients with HIV-related diarrhea. The purpose of this study is to compare the diagnostic yield of a complete endoscopic work-up including an esophagogastroduodenoscopy and colonoscopy to a more limited approach of biopsies obtainable by flexible sigmoidoscopy. METHODS: A prospective study of 79 patients with HIV-related diarrhea. Upper endoscopy and colonoscopy were performed with tissue biopsies labelled according to location within the colon or small intestine. RESULTS: A new infection was diagnosed in 22 of 79 patients (28%). Biopsy of the left colon yielded an enteric pathogen in 17 of 22 patients (sensitivity: 77%) and in 15 of 15 patients with cytomegalovirus colitis (sensitivity: 100%). Combined left and right colonic biopsies had a sensitivity of 82%. Combined colonic and terminal ileum biopsies missed no pathogens. Duodenal biopsies yielded no additional pathogens beyond those identified by colonoscopy and terminal ileal biopsy. Patients with a new pathogen diagnosed had significantly lower CD4 lymphocyte counts as compared to patients without a new pathogen (p = 0.001). CONCLUSIONS: For patients with CD4 counts < 100/mm3 and unexplained AIDS-related diarrhea, flexible sigmoidoscopy with biopsy is a sufficiently thorough endoscopic evaluation.

AIDS-Related Opportunistic Infections↗
PubMed1999

Do we practice what we preach? clinical decision making and utilization of endoscopic ultrasound for staging esophageal cancer.

OBJECTIVES: Endosonography is accurate for staging esophageal cancer. However, whether detailed staging impacts clinical decision making, whether endosonography is perceived as a useful modality, and what factors influence the utilization of endosonography have not been studied. METHODS: One hundred gastroenterologists were surveyed about staging and management of esophageal cancer, including: 1) management by stage; 2) perceived usefulness of endosonography; 3) availability of endosonography; and 4) number of patients referred. RESULTS: Clinical decisions varied by incremental differences in tumor stage. However, only 27 of 66 respondents (40.9%) judged endosonography to be very useful or essential for the evaluation of esophageal cancer and only 22 (33.3%) had referred a patient. Perceived usefulness and availability were independent factors strongly associated with referral for endosonography. Among 18 respondents to whom endosonography was available and who considered it useful, 14 (77.9%) had referred a case. In contrast, a conservative management was not associated with either perceived usefulness of or referral for endosonography. CONCLUSIONS: Clinicians recognize the importance of detailed staging for management of esophageal cancer. Despite this, they underestimate the utility of endosonography and fail to refer patients for appropriate evaluation. Lack of perceived usefulness and unavailability are important independent barriers to utilization of endosonography in clinical practice.

Attitude of Health Personnel↗
PubMed1999

Evaluation of upper gastrointestinal tract symptoms in patients infected with HIV.

OBJECTIVE: Upper gastrointestinal tract (UGI) symptoms are frequent in patients infected with the human immunodeficiency virus (HIV), but little published information exists about their characteristics or methods of evaluation. We evaluated the prevalence of nonesophageal UGI symptoms in a referral population, the utility of esophagogastroduodenoscopy (EGD) for diagnosis, and clinical predictors of abnormal endoscopic findings in patients infected with HIV. METHODS: All HIV-infected patients referred to.the outpatient gastroenterology clinics were prospectively evaluated using recognized symptom questionnaires. EGD indications, results, and the patients' self-reported symptom scores were compared. HIV-infected patients undergoing EGD were compared with HIV-infected patients not receiving an EGD and with symptomatic non-HIV-infected patients undergoing EGD. RESULTS: A total of 201 patients completed 280 questionnaires. Among 93 patients who underwent endoscopy, severe symptoms occurring at least several times per week included: anorexia (70%), upper abdominal pain (34%), vomiting (32%), or a recent weight loss of approximately 15 lb (31%). Patients undergoing EGD had more frequent/severe symptoms, but did not have differences in overall well-being or mean GI symptom score. The frequency of substantial and treatable endoscopic findings among patients infected with HIV was comparable to that found in the non-HIV-infected control group. There were no independent symptoms predicting substantial or treatable disease on EGD. CONCLUSIONS: We conclude that: 1) upper gastrointestinal symptoms are common in HIV-infected patients referred for GI consultation; 2) symptomatic HIV patients have a high prevalence of both treatable and untreatable upper GI pathologies; 3) and physicians use symptom frequency and severity to select patients for EGD, but these factors correlate poorly with abnormalities on EGD. Given this discrepancy, longitudinal study is needed to determine whether treating endoscopic abnormalities improves UGI symptoms.

Endoscopy, Gastrointestinal↗
PubMed1999

A double blind, randomized, placebo-controlled phase II study to assess the safety and efficacy of orally administered SP-303 for the symptomatic treatment of diarrhea in patients with AIDS.

OBJECTIVE: The aim of this study was to investigate the safety and effectiveness of orally administered SP-303 in patients with AIDS and diarrhea. METHODS: This is a multicenter, phase II, randomized, double blind, placebo-controlled study. HIV-positive subjects with a history of a CD4 count <200 or an AIDS-defining illness were admitted to an inpatient study unit and screened for diarrhea defined as at least three abnormal (i.e., soft or watery) stools and >200 g of abnormal stool weight over a 24-h period. Subjects discontinued all antidiarrheal agents >24 h before enrollment. Stool samples were studied for routine pathogens. Subjects received 500 mg p.o. of SP-303 or placebo every 6 h for 96 h (4 days). Stool frequency and weights were recorded. Subjects were monitored for symptoms and side effects and were seen 1 wk later in follow-up. RESULTS: A total of 26 subjects received SP-303, and 25 received placebo. There were no significant demographic differences between treatment arms. A total of 41 subjects (80%) were receiving antiretroviral therapy and 39 subjects (77%) were receiving at least one protease inhibitor. Stool studies revealed no pathogens in 48 of 51 patients (94%). There were no serious adverse events or laboratory abnormalities. The SP-303 treatment group demonstrated a mean reduction from baseline stool weight of 451 g/24 h versus 150 g/24 h with placebo on day 4 of treatment (p = 0.14), and a mean reduction in abnormal stool frequency of three abnormal stools in 24 h versus two in 24 h in the placebo group (p = 0.30). Daily measures analysis over 4 days of treatment demonstrated that SP-303 subjects had a significant reduction in stool weight (p = 0.008) and abnormal stool frequency (p = 0.04) when compared to placebo-treated subjects. CONCLUSIONS: SP-303 is safe and well tolerated. These results suggest that SP-303 may be effective in reducing stool weight and frequency in patients with AIDS and diarrhea.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Telomeric repeat organization--a comparative in situ study between man and rodent.

Human, hamster, and mouse chromosomes show both similarities and differences in telomeric organization, detectable with a novel version of the PRINS technique. The differences allowed us to investigate the fate of the telomeres on a chromosome from one species when this chromosome was introduced into the cells of another species. For this purpose, we tested telomeres in cell lines of somatic cell hybrids containing human chromosomes on a rodent background, finding that the telomeres on human chromosomes could not be discriminated from the telomeres on rodent chromosomes. All telomeres in the cell lines were much shorter than the telomeres in normal cells. In the mouse-derived cell lines, half of the mouse chromosomes were fused to other mouse chromosomes at the ends of their short arms. At the points of fusion we were generally unable to detect telomeric signals. In these cell lines, we also found a fraction of chromosomes ends with only one telomeric signal. In chromosomes where both ends showed only one signal, the relative orientation of the signals appeared to be nonrandom with respect to sister chromatids.

Animals↗
PubMed1999

CT appearance of a renal aspergilloma in a patient with the acquired immunodeficiency syndrome.

The appearance of a unilateral renal aspergilloma on computed tomography is described in a 32-year-old man with acquired immunodeficiency syndrome (AIDS). Aspergillus infections are uncommon in the AIDS population. Only 9 cases of renal aspergilloma have been described in AIDS. The treatment performed was percutaneous drainage followed by antifungal drug administration and unilateral nephrectomy. This case report emphasizes the fact that renal fungal infections need to be considered in differential diagnosis of kidney infections in AIDS patients.

AIDS-Related Opportunistic Infections↗
PubMed1998

Discrepancy between sex- and water-associated risk behaviors for cryptosporidiosis among HIV-infected patients in San Francisco.

OBJECTIVE: Potential transmission of cryptosporidiosis through drinking water supplies has been highly publicized; however, it is unknown whether this reporting has increased patient awareness or reduced other risk behaviors for exposure to this organism, such as high-risk sexual behavior. METHODS: Consecutive patients presenting for initial evaluation to the Gastroenterology AIDS Clinic completed a questionnaire that assessed knowledge about cryptosporidiosis, perceived risk of infectious diarrhea, drinking water sources, and high-risk sexual behavior. RESULTS: Fifty-one patients completed the questionnaire (82% male; 86% homosexual; mean age, 38 years; median CD4 count, 136 x 10(6) cells/L). Most respondents (31 of 44; 70%) believed they were at risk for infectious diarrhea. Awareness of cryptosporidiosis was high (31 of 45; 69%) as was avoidance of tap water (26 of 51; 51%) and exclusive or frequent use of bottled or boiled water (40 of 51; 78%). Respondents who used bottled water reported spending an average of $331.76 U.S. annually. However, high-risk sexual behavior remained common: 21 (41%) of the 51 subjects reported unprotected anal intercourse or oral-anal sexual contact. High-risk sexual behavior was prevalent even among subjects who drank exclusively boiled or bottled water. CONCLUSIONS: Awareness of risk for infectious diarrhea and cryptosporidiosis is high among patients infected with HIV in San Francisco. Patients perceive drinking water to be a substantial risk factor for infectious diarrhea and incur significant expense to avoid tap water. However, high-risk sexual behaviors remain prevalent in this population and should be the focus of future education efforts.

Adult↗
PubMed1998

Relative frequency of upper gastrointestinal and colonic lesions in patients with positive fecal occult-blood tests.

BACKGROUND: Although bleeding lesions anywhere in the gastrointestinal tract can cause a positive reaction on guaiac-based fecal occult-blood tests, the relative frequency of upper gastrointestinal and colonic lesions is unknown. METHODS: During a period of 30 months, we prospectively studied all patients with at least one stool specimen containing fecal occult blood who were referred for further evaluation. Fecal occult blood was detected by standard guaiac-based tests of stool specimens obtained as part of routine screening or of stool obtained by digital rectal examination. Patients with documented iron-deficiency anemia or active gastrointestinal bleeding were excluded from the study. All participants had a detailed history taken and underwent colonoscopy, followed by esophagogastroduodenoscopy. RESULTS: Of the 409 patients with fecal occult blood who were referred, 310 were potentially eligible to participate, and 248 (mean age, 61 years; range, 40 to 89) were studied; 40 percent were women. We identified lesions consistent with occult bleeding in 119 patients (48 percent); in 71 bleeding lesions were found in the upper gastrointestinal tract, and in 54 they were identified in the colon. Six patients had abnormalities in both areas. The most common upper gastrointestinal lesions were esophagitis (23 patients), gastric ulcer (14), gastritis (12), and duodenal ulcer (10). Thirty patients with lesions in the upper gastrointestinal tract were long-term users of aspirin, ethanol, nonsteroidal antiinflammatory drugs, or a combination of these substances. The most common colonic lesions were adenomas more than 1.0 cm in diameter (29 patients), carcinoma (13), colitis (5), and vascular ectasia (5). Although the overall sensitivity of symptoms for the detection of gastrointestinal lesions was low, logistic-regression analysis demonstrated that the presence of symptoms in the upper gastrointestinal tract was associated with the detection of lesions in the upper gastrointestinal tract (odds ratio, 2.6; 95 percent confidence interval, 1.4 to 4.7). In both patients with symptoms and those without symptoms, the prevalence of lesions in the upper gastrointestinal tract was greater than or equal to that of colonic lesions. CONCLUSIONS: In a group of patients with positive fecal occult-blood tests who were referred for further evaluation, from which those with iron-deficiency anemia and active bleeding had been excluded, upper gastrointestinal lesions were identified more frequently than colonic lesions.

Aged↗
PubMed1998

[Intermittent fever of unknown origin].

HISTORY AND CLINICAL FINDINGS: A 58-year-old woman was admitted because of intermittent fever for 4 weeks accompanied by slowly developing anaemia and increase in inflammatory parameters. She was being treated for hypertension with atenolol and chlorthalidone, but until 6 weeks before the onset of the described symptoms she had only taken the beta blocker, at which time the diuretic was added because the hypertension was inadequately controlled. Other than slightly impaired general condition and nocturnal fever up to 39.5 degrees C physical examination was unremarkable. INVESTIGATIONS: She had a normochromic normocytic anaemia and the erythrocyte sedimentation rate and C-reactive protein were clearly elevated. Other biochemical tests and blood cultures as well as serological and immunological tests were negative. Bone marrow biopsy showed nonspecific reactive changes. The chest radiograph, lung scintigraphy and abdominal ultrasound were unremarkable. TREATMENT AND COURSE: There was no further fever after the antihypertensive medication had been discontinued. The patient's general condition rapidly improved and all biochemical tests became normal. The lymphocyte transformation test demonstrated stimulation by chlorthalidone. CONCLUSION: Drug fever, in this case due to a sulphonamide derivative, should always be considered in the differential diagnosis of fever of unknown aetiology. No previous case of hypersensitivity reaction to chlorthalidone has been found on a search of the literature.

Antihypertensive Agents↗