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Biomedical subjects

K Dalhoff

Publications and source records attributed to K Dalhoff.

At least 91 records · Page 5Linked to original sources
PubMed1996

Expression of liver-specific functions in rat hepatocytes following sublethal and lethal acetaminophen poisoning.

AIM: In order to study the short-term effect of moderate and severe reduction of liver function by acetaminophen poisoning of different severity on gene expression for liver-specific functions, rats were given 3.75 and 7.5 g per kg body weight acetaminophen intragastrically. The lower dose is associated with low mortality; after the higher dose, most rats die at between 12 and 24 h. METHODS: In the morning, 1 1/2, 3, 6, 9, and 12 h after the injection, the rats were killed and RNA was extracted from liver tissue. By slot-blot hybridization mRNA steady-state levels were determined for enzymes involved in metabolic liver functions, i.e. ureagenesis, gluconeogenesis, and drug metabolism, for acute phase proteins, "house-keeping" proteins, and for proteins related to liver regeneration. Results were expressed as per cent of the level in similarly fasted, untreated rats of the same stock RESULTS: After the smaller dose of acetaminophen, most of the examined mRNA levels were increasing during the experimental period, being two- to four-fold elevated in relation to control after 6 to 12 h. Rats receiving the lethal dose either showed no or a later and smaller increase, and in several cases a fall towards the end of the experiment. The greatest differences were seen for mRNA of arginase, beta-fibrinogen, alpha 1-acid glycoprotein, alpha-tubulin, histone 3, TGF beta, and cyclin d, i.e. proteins associated with acute phase response and liver cell replication and maintenance. CONCLUSIONS: It is concluded that reversible intoxication with acetaminophen induces an adaptive modulation of mRNA expression of liver functions and regeneration which is lacking after severe intoxication. This adaptation, with emphasis on acute phase response and regeneration, may be crucial for recovery after acetaminophen intoxication. If this also applies to the intoxication in man, estimates of the corresponding variables may be clues to the prognosis of acetaminophen-induced fulminant hepatic failure.

Acetaminophen↗
PubMed1996

Detection of Mycoplasma sp. in bronchoalveolar lavage of AIDS patients with pulmonary infiltrates.

We examined 486 bronchoalveolar lavages (BAL) including 32 from AIDS patients with pulmonary infiltrates and 20 from patients with leukemia or after transplantation. Mycoplasmas were found in 4/32 (12.5%) HIV-positive patients compared to 4/454 (< 0.9%) HIV-negative patients (p < 0.001). All of these four HIV-positive patients suffered from advanced infection (CD4 counts < 100/microL) and developed complications (Pcp, n = 2, recurrent bacterial pneumonia, n = 1, pulmonary Kaposi sarcoma, n = 1). No mycoplasmas were detected in 20 immunosuppressed patients with leukemia or after transplantation. Our data indicate that AIDS patients may be more often colonised or infected by mycoplasmas than HIV-negative patients or other immunocompromised persons. Although the etiological role of mycoplasmas for pulmonary infections in these patients remains unclear, the finding of mycoplasmas was associated with rapid progress and development of severe complications in our study.

AIDS-Related Opportunistic Infections↗
PubMed1996

Chlamydia pneumoniae pneumonia in hospitalized patients. Clinical characteristics and diagnostic value of polymerase chain reaction detection in BAL.

STUDY OBJECTIVE: To evaluate the incidence and clinical characteristics of Chlamydia pneumoniae infection as detected by polymerase chain reaction (PCR) and culture of BAL in hospitalized patients with pneumonia, HIV-infected persons, and control subjects. DESIGN: Prospective, comparative clinical study. SETTING: University hospital medical center. PATIENTS: Fifty-seven hospitalized patients with acute lower respiratory tract infection (group 1); 47 HIV-positive patients (group 2); 100 patients with noninfectious bronchopulmonary disorders (group 3). INTERVENTIONS: BAL was performed in all patients at hospital admission for diagnostic purposes. In addition to semiquantitative bacterial and fungal culture, isolation and detection of C pneumoniae were performed by cell culture and PCR of the lavage fluid. MEASUREMENTS AND RESULTS: C pneumoniae was detected in 16% of group 1, 13% of HIV-positive persons, and 0% of control subjects. The sensitivity of chlamydial culture was much lower as compared with PCR (4 vs 15 cases). In contrast to group 1, in the HIV-positive patients, acute respiratory symptoms were not always present, and in 3 of 6 cases, copathogens were found in the BAL. BAL differential cell counts disclosed a significant lymphocyte elevation mostly due to the CD8 subset (group 1: 15% vs 5%; group II: 18.5% vs 4%; C pneumoniae positive vs negative cases, respectively). CONCLUSIONS: C pneumoniae is frequently detected in the BAL of hospitalized patients with pneumonia as sole pathogen. PCR detection is highly specific and far more sensitive than cell culture. Asymptomatic carriage seems to be uncommon in immunocompetent patients, but does occur in HIV-positive patients. A lymphocytic alveolitis is frequently found by BAL cytologic study and may represent a T-cell response to chlamydial infection in the lower respiratory tract.

AIDS-Related Opportunistic Infections↗
PubMed1995

Fas (CD95) expression on CD4+ T cells from HIV-infected patients increases with disease progression.

Active T cell suicide (apoptosis) is supposed to be involved in the CD4+ T cell depletion in the course of HIV infection. We investigated the expression of the apoptosis-related antigen Fas on CD4+ T cells from 25 HIV-positive individuals (CDC I-III) and 8 HIV-negative controls by two-colour flowcytometry. In addition, we evaluated: total CD4 count, HIV p24 antigen concentration in serum after immune complex dissociation, and clinical course of infection in HIV-positive individuals. We found a significant increase in mean Fas expression on CD4+ T cells from HIV-positive individuals compared to HIV-negative individuals (85.84 +/- 14.92% vs. 64.28 +/- 7.59%, P < 0.001). Within the HIV-positive group the increase in Fas expression was correlated with the decline in CD4 count (r = -0.76, P < 0.001), p24 antigen concentration in serum, after immune complex dissociation (r = 0.67, P < 0.001), and CDC stage (r = 0.73, P < 0.001). The upregulation of Fas antigen on CD4 cells is associated with CD4 depletion and other virological and clinical marker of disease progression in HIV infection.

Adult↗
PubMed1995

HIV p24 antigen concentration in serum of 11 anti-HIV 1-positive patients before and after immune-complex dissociation: a study of a 5-year period.

BACKGROUND: Determination of the p24 antigen of the human immunodeficiency virus type 1 (HIV 1) is widely used to monitor viral activity though it is well known that substructures with p24 specificity present in serum can be complexed with specific antibodies, thereby preventing them from being detected by regular p24 antigen detection assays. OBJECTIVES: To compare the regular assay for p24 antigen with a procedure that dissociates immune-complexes before determination of this antigen. STUDY DESIGN: Eleven HIV 1-infected patients were followed for up to 5 years in order to obtain continuity in terms of the development of the p24 antigen in comparison with other surrogate markers. RESULTS: The results show that even low concentrations of anti-p24 antibodies are able to complex p24 antigens, rendering them undetectable in the routine assay. p24 antigens became detectable only after dissociation of these immune complexes by acid treatment procedure. In most patients viral activity became demonstrable only after application of the dissociation procedure.

Journal Article↗
PubMed1995

Transport and storage conditions for cultural recovery of Chlamydia pneumoniae.

Chlamydia pneumoniae is characterized by rapidly decreasing viability outside the host cell, and efficient preservation of its infectivity is a prerequisite for subsequent cell culture recovery. Extracellular survival of three C. pneumoniae stock strains and three wild-type strains subjected to simulated conditions of transport was therefore examined in order to establish recommendations for transport and storage of clinical specimens. The presence of fetal calf serum in transport media as well as refrigeration distinctly improved chlamydial retrieval during prolonged transport. Loss of infectivity was kept to a minimum in Eagle's minimal essential medium or sucrose-phosphate-glutamine medium. Storage at 22 degrees C permitted a stock strain recovery of 81% after 12 h. When refrigeration to 4 degrees C was provided, recovery rates of 74% could be achieved after 48 h. Though the strains were from different geographic regions, requirements for good survival were comparable and should therefore apply worldwide. The results indicate that the laboratory strains are not extremely labile. However, comparative examination of the wild-type strains showed less stability: primary isolates were not satisfactorily retrievable beyond 4 h at 22 degrees C or beyond 24 h at 4 degrees C. Further extension of storage times resulted in rapidly decreasing recovery, indicating a requirement to freeze samples at -75 degrees C to preserve viability. Adherence to the shorter storage periods suggested by the data obtained with primary isolates is recommended to ensure successful transport until more extensive testing with clinical materials is available.

Bacteriological Techniques↗
PubMed1995

[Pentoxifylline inhibits secretion of O2- and TNF-alpha by alveolar macrophages in patients with sarcoidosis].

Reactive oxygen species (ROS) and cytokines like tumor necrosis factor-alpha (TNF-alpha) play a crucial role as inflammatory mediators in pulmonary sarcoidosis. We examined the antiinflammatory effect of pentoxifylline (POF) on alveolar macrophages (AM) of patients with sarcoidosis in vitro. We could demonstrate that POF (above 4.10(-4) M) inhibited the secretion of superoxide anion and TNF-alpha by AM in a dose-dependent manner via a prostaglandin synthesis-dependent mechanism that was independent of the glucocorticoid receptor. POF is an interesting immunomodulating substance that should be further evaluated in clinical trials.

Adult↗
PubMed1994

[Isolation of Chlamydia pneumoniae in atypical pneumonia].

A 33-year-old man, who two months previously had been treated for bronchopneumonia with cefuroxime, fell ill again with cough, dyspnoea and fever up to 39.8 degrees C. Auscultation and lung function tests indicated respiratory tract obstruction. The chest radiograph revealed an infiltrate of the left lower lobe and bronchoscopy showed hypertrophic bronchitis. Empirical antibiotic treatment with clarithromycin (initially 500 mg twice daily, continued on half this dose) lead to rapid improvement of clinical symptoms and the patient could be discharged after 9 days. A follow-up examination 3 months later showed no abnormality. A cell culture procedure using bronchoalveolar lavage fluid obtained during bronchoscopy permitted the continuous demonstration of Chlamydia pneumoniae inclusions in HEp-2 host cells by immunofluorescence microscopy. In parallel, Chlamydia pneumoniae DNA was specifically demonstrated in the lavage fluid by use of the polymerase chain reaction. This is the first reported isolation of a replicative Chlamydia pneumoniae strain in Germany.

Adult↗
PubMed1994

Comparison of sample preparation methods for detection of Chlamydia pneumoniae in bronchoalveolar lavage fluid by PCR.

Amplification inhibitors can lead to false-negative results for PCR. In order to evaluate the reliability of PCR for the detection of Chlamydia pneumoniae, the presence of PCR inhibitors in 75 bronchoalveolar lavage specimens was assessed after treatment by various sample preparation methods. Specimens were collected from patients with acute respiratory infections, including four cases of proven C. pneumoniae infection. Substances inhibitory to the amplification of chlamydial DNA continued to be present in 12% of the samples treated according to the commonly used single-step proteinase K digestion and in 31% of the samples processed by heat treatment. However, the complexing of DNA-contaminating proteins and polysaccharides from digested specimens to cetyltrimethylammonium bromide (CTAB) followed by DNA extraction efficiently removed inhibitors from all experimental samples and provided subsequent identification of all positive clinical samples by PCR. The CTAB method and proteinase K treatment had comparable detection limits of approximately 0.01 inclusion-forming units. CTAB-based DNA purification of respiratory specimens is recommended to increase the diagnostic sensitivity of PCR and confidence in negative results.

Bronchoalveolar Lavage Fluid↗
PubMed1994

Oxidative metabolism of pulmonary phagocytes in acute pneumonia.

The oxidative response of activated phagocytes is a primary host defense mechanism in pneumonia, but is in addition capable of causing tissue damage. We evaluated amount and significance of the local oxidant production in immunocompetent and immunocompromised pneumonia patients; the relative contribution of neutrophils and alveolar macrophages to the total oxidant load was differentiated using chemiluminescence (CL) with different amplifiers. Luminol-enhanced CL correlated to neutrophil percentage and myeloperoxidase levels in the bronchoalveolar lavage and was markedly increased in both pneumonia groups. Lucigenin-enhanced CL was produced by both phagocyte types and not significantly increased. In both pneumonia groups elevated levels of serum proteins indicated severe alveolocapillary leakage. In conclusion the oxidative response in acute pneumonia was mainly due to neutrophil recruitment and activation; this defense mechanism was preserved even in severely immunocompromised patients.

Acute Disease↗
PubMed1994

Characterization of protein-antiproteinase imbalance in bronchoalveolar lavage from patients with pneumonia.

In order to clarify the mode of inactivation of alpha1-proteinase inhibitor (alpha 1-PI) in pneumonia, 21 immunocompetent patients and 19 immunocompromised patients with acute pneumonia (Groups I and II) were studied. Nine patients successfully treated for pneumonia and 10 healthy volunteers served as controls (Groups III and IV, respectively). The concentrations of alpha 1-PI, elastase and myeloperoxidase (MPO) in bronchoalveolar lavage fluid (BALF) were determined using a luminometric assay. Elastase inhibition capacity was determined using a colorimetric assay. Thus, the functional activity of alpha 1-PI was calculated. Both elastase and MPO were significantly higher in group I, when compared with the other groups. The mean concentration of alpha 1-PI was significantly higher in patients with acute pneumonia (Group I 13 mg.l-1, Group II 4.22 mg.l-1) than in Groups III and IV (2.65 and 0.33 mg.l-1, respectively), whereas, the proportion of active alpha 1-PI was significantly lower in Group I than in the other groups. Only a small proportion was present as a complex with elastase (ca. 5.9%) or in oxidised form (ca. 4.8%), 85% of alpha 1-PI was irreversibly proteolyzed. This resulted in free elastase activity in 7 of the 40 patients (18%) with acute pneumonia. We conclude that functional activity of alpha 1-PI is markedly impaired due to irreversible proteolysis in acute pneumonia, despite high immunological concentrations.

Adult↗
PubMed1994

Intercellular adhesion molecule-1 (ICAM-1) is upregulated on alveolar macrophages from AIDS patients.

In acquired immune deficiency syndrome (AIDS) patients, alveolar macrophages (AMs) have an increased ability to serve as accessory cells during the generation of an immune response. In addition to soluble mediators, like cytokines, molecules of the major histocompatibility complex (MHC) class II and adhesion molecules, like intercellular adhesion molecule-1 (ICAM-1), play a major role in the regulation of these cellular interactions. Using an enzyme-linked immunosorbent assay (ELISA) technique and immunocytochemical staining, we investigated ICAM-1 and human leucocyte antigen-DR (HLA-DR) expression on AMs from 20 AIDS (HIV+) patients in context with other parameters of macrophage activation, such as tumour necrosis factor-alpha (TNF-alpha) secretion and the release of superoxide anion, comparing the results to a group of healthy volunteers. In addition, we quantified soluble ICAM-1 in the bronchoalveolar lavage fluid (BALF) using a commercially available kit. We found a nearly twofold increase in ICAM-1 expression (0.81 +/- 0.30 (SD) versus 0.42 +/- 0.12 ELISA units (EU) (mean +/- SD)), whilst the number of HLA-DR+ AMs was slightly decreased in AIDS-patients (80 +/- 5 versus 89 +/- 3%). Furthermore, soluble ICAM-1 in the BALF of these patients was significantly increased (41.9 +/- 26.1 versus 19.1 +/- 5.1 ng.ml-1). ICAM-1 levels on AMs in the patient group correlated strongly with the sodium fluoride triggered release of superoxide anion (O2-) but not with the spontaneous secretion of TNF-alpha by AMs.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1994

A rapid semiautomatical enzyme linked immunoassay identifying intercellular adhesion molecule-1 (ICAM-1) on the alveolar macrophage surface.

Intercellular adhesion molecule-1 (ICAM-1), a member of the immunoglobulin gene superfamily, is a cytokine-inducible adhesion molecule, which plays a central role in leukocyte migration into sites of acute or chronic inflammation. In this article we describe a sandwich immunoenzymometric method which allows rapid, semiquantitative (in "enzyme immunoassay units", EU) identification of ICAM-1 on the surface of alveolar macrophages. We evaluated this method in two groups of patients with pulmonary sarcoidosis (n = 12) or bacterial pneumonia (n = 11) and a group of healthy volunteers (n = 6), comparing the results with those obtained by immunocytochemical staining. ICAM-1 expression on the sarcoid alveolar macrophages surface was significantly elevated, as compared with control alveolar macrophages (0.76 EU +/- 0.27 vs. 0.44 EU +/- 0.12, p < 0.01). ICAM-1 expression on the surface of alveolar macrophages from patients with pneumonia was not elevated (0.48 EU +/- 0.35). Stimulation with tumour necrosis factor-alpha (TNF-alpha) or interferon-gamma (100 kU/l) led to a significant induction of ICAM-1 on the surface of control alveolar macrophages (0.76 EU +/- 0.18, p < 0.005 for TNF-alpha, 0.64 EU +/- 0.10, p < 0.005 for interferon-gamma), whereas alveolar macrophages from both patient groups did not respond to cytokines even at high dosages. ICAM-1 expression on the surface of alveolar macrophages from patients with sarcoidosis correlated with the spontaneous release of TNF-alpha by macrophages (R = 0.77, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Endobronchial actinomycosis.

Endobronchial actinomycosis was found to be the cause of right-sided atelectasis and haemoptysis in a 57 year old man without predisposing conditions. Fibreoptic bronchoscopy revealed occlusion of the intermediate bronchus by yellow-white masses. The diagnosis was confirmed histologically and by positive Actinomyces culture from bioptic material. Prolonged antibiotic treatment resulted in complete recovery, without need for surgical resection.

Actinomycosis↗
PubMed1993

Synthesis rates of glutathione and activated sulphate (PAPS) and response to cysteine and acetaminophen administration in glutathione-depleted rat hepatocytes.

The effects of cysteine and acetaminophen (AA) on the synthesis rates of glutathione (GSH), adenosine 3'-phosphate 5'-phosphosulphate (PAPS, activated sulphate) and the AA metabolites, AA-GSH and AA-sulphate were studied in rat hepatocytes depleted of GSH by diethyl maleate (DEM). The synthesis rates were determined simultaneously by a previously described radioactive tracer method. Preincubation of the hepatocytes with 0.7 mM DEM for 30 min depleted GSH by 59% (P < 0.05) and PAPS by 28% (P < 0.05). Incubation with a toxic AA concentration resulted in GSH synthesis at a rate of 95 nmol/(10(6) cells.min) which increased to 281 nmol/(10(6) cells.min) (P = 0.05) after addition of cysteine. However, increased GSH synthesis was not followed by increased AA-GSH synthesis [4.7 vs 4.8 nmol/(10(6) cells.hr)]. Also, PAPS synthesis increased after cysteine administration [10.2 to 19.1 nmol/(10(6) cells.min)] (P < 0.05) without any change in AA-sulphate synthesis 18.5 vs 18.3 nmol/(10(6) cells.hr)]. Thus, in contrast to hepatocytes with normal GSH concentration, cysteine stimulated both GSH and PAPS synthesis rates in GSH-depleted rat hepatocytes incubated with a toxic AA concentration without stimulation of AA-GSH or AA-sulphate synthesis rates, indicating that the hepatoprotective effect of cysteine on AA toxicity is primarily due to stimulation of a GSH-mediated reduction of the reactive AA metabolite N-acetyl-p-benzoquinoneimine back to AA.

Acetaminophen↗