Search PubMed⌕ Search

Biomedical subjects

T Schaberg

Publications and source records attributed to T Schaberg.

At least 91 records · Page 5Linked to original sources
PubMed1995

Subpopulations of alveolar macrophages in smokers and nonsmokers: relation to the expression of CD11/CD18 molecules and superoxide anion production.

We were previously able to show that the number of alveolar macrophages (AM) expressing CD11/CD18 molecules is increased in smokers compared with nonsmokers and related to the superoxide anion (O2-) production of these cells. Since it has been demonstrated that AM are a heterogeneous cell population that can be separated by density, we performed this study to investigate the expression of CD11/CD18 molecules and O2- production in relation to cell density of AM from smokers and nonsmokers. AM were obtained by bronchoalveolar lavage (BAL) from smokers (n = 32) and nonsmokers (n = 20). Subpopulations were isolated using discontinuous Percoll density-gradient centrifugation with four densities (fraction 1: 1.030; fraction 2: 1.040; fraction 3: 1.050; and fraction 4: 1.070 g/ml). Expression of CD11/CD18 on freshly isolated cells and on AM before and after density centrifugation was studied using peroxidase-antiperoxidase staining. The contribution of AM subpopulations to O2- production in smokers was determined by monitoring the reduction of ferricytochrome C to ferrocytochrome C. We obtained 0.92 +/- 0.1 x 10(5) AM/ml BAL in nonsmokers and 2.4 +/- 0.3 x 10(5) AM/ml in smokers. Recovery after density centrifugation was > or = 72%. The absolute number of AM in smokers was significantly increased in fractions 3 and 4 (median 4.37 x 10(6) and 2.05 x 10(6), respectively) compared with nonsmokers (median 1.26 x 10(6) and 0.7 x 10(6), respectively) (p < 0.05). In both smokers and nonsmokers, fractions 3 and 4 showed a comparable increase in the percentage of CD11/CD18-positive AM compared with fractions 1 and 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Drug-resistant pulmonary tuberculosis in Berlin, Germany, 1987-1993.

Resistance of Mycobacterium tuberculosis (M.tb) strains is an increasing problem worldwide. Since no public health data are available for urban populations in Germany, we investigated resistance in our hospitalized patients (n = 1,011) over the last 7 yrs. We therefore evaluated clinical data and results of susceptibility tests (breakpoint technique/proportion method) for isoniazid, streptomycin, rifampin, pyrazinamide, protionamide and ethambutol. Since 1987, there has been a relatively constant rate of 5.9% (3.9%-7.8%) for single-drug resistance (SDR), but an increasing rate of multidrug-resistant (MDR) strains (> or = 2 first-line drugs) from 1.7% in 1987 to 5.8% in 1993. Sixty nine percent of patients with MDR strains showed resistance to two drugs, and 31% to three or more drugs. Risk factors for SDR and MDR tuberculosis revealed previous therapy (odds ratio (OR) (95% confidence interval (95% CI)); SDR 2.2 (1.7-4.0); MDR 4.5 (2.3-8.8)); and foreign-born status (SDR 2.2 (1.3-3.6); MDR 3.5 (1.8-6.8)) to be the most important factors associated with resistance. Both primary and acquired resistance were higher in foreign-born than in German-born patients. We conclude that there was a considerable increase in multidrug-resistant tuberculosis in our hospital from 1987 to 1993. Since previously treated patients and patients born in countries with a high level of primary resistance had an increased risk of drug-resistant tuberculosis, we would advise a four drug regimen as initial therapy in those patients.

Adult↗
PubMed1995

Rapid drug susceptibility testing of Mycobacterium tuberculosis using conventional solid media.

Radiometric methods for M. tuberculosis drug susceptibility testing yield much faster results than standard techniques; however, these methods require sophisticated equipment and are expensive. We investigated a rapid drug susceptibility testing method for isoniazid, rifampin, ethambutol, streptomycin and pyrazinamide in specimens from 197 patients with pulmonary tuberculosis using a simplified agar-dilution method. Middlebrook 7H11 agar solid medium and microcolony detection were used to test sputum from 64 smear-positive, and from 70 culture-positive but smear-negative patients. Culture-positive material from bronchoscopy, surgical biopsy, pleural fluid or gastric fluid of 63 patients was tested. In 64 smear-positive patients, the median time for final susceptibility results was 11 days (95% confidence interval (95% CI) 10-12 days) compared to 62 days (95% CI 56-66 days) with the standard method. In 133 smear-negative patients, results were available after a median of 35 days (95% CI 32-40 days) in contrast to 72 days (95% CI 62-83 days) with the standard method, regardless of whether or not sputum or other materials were used for primary culture. The rapid method detected all cases of single-drug resistance (n = 20) and multidrug resistance (n = 14) within 13 days (95% CI 9-17 days) in smear-positive patients (n = 8), or within 38 days (95% CI 35-48 days) in smear-negative patients (n = 26). Only one discrepancy was encountered in 985 resistance tests. Moreover, contamination was not observed. Our rapid susceptibility testing method for M. tuberculosis on Middlebrook 7H11 agar is fast, practical and inexpensive. It provides an alternative when more sophisticated techniques are not available or affordable.

Adolescent↗
PubMed1995

Changing role of carbapenems in the treatment of lower respiratory tract infections.

The acquisition of antibiotic-resistance genes by virtually all major bacterial pathogens is currently a world-wide phenomenon. This problem is especially evident in nosocomial lower respiratory tract infections (LRTI). Carbapenems like imipenem and meropenem offer interesting antibacterial activities and beta-lactamase-stability, as well as adequate pharmacokinetic characteristics, to cover most of the pathogens involved in moderate to severe community-acquired and nosocomial LRTI. In contrast to imipenem, meropenem is not nephrotoxic and offers the advantage of greater stability against renal dehydropeptidase-I, so no concomitant application of an enzyme inhibitor is necessary. Meropenem can also be given by intravenous infusion or injection without the nausea and vomiting often associated with the administration of imipenem/cilastatin. Preliminary results with meropenem in LRTI show excellent cure rates and good tolerance for this new carbapenem.

Adolescent↗
PubMed1994

[Incompatibility of tuberculosis therapy in a patient with AIDS].

A man with advanced HIV infection (CD4 lymphocytes 90/microliter, CD4/CD8 ratio 0.2) was admitted to hospital with fever, cough and weight loss. The radiological and bronchoscopic findings, together with the presence of acid-fast bacilli in the sputum, pointed to open pulmonary tuberculosis caused by Mycobacterium tuberculosis, a diagnosis confirmed by histological examination and culture. Quadruple antibiotic therapy with isoniazid (INH), rifampicin (RMP), ethambutol (EMB) and amikacin was immediately begun and was at first clinically successful. Ten days later, however, a rash appeared; it was ascribed to RMP (anaphylactoid reaction after re-exposure). All the other first-line drugs tried during the ensuing eight months evoked severe adverse reactions (INH: rash and itching; amikacin: hearing impairment and tinnitus; EMB, pyrazinamide, prothionamide, p-aminosalicylic acid: rash and itching). Treatment was nevertheless clinically and microbiologically successful, and the patient insisted upon a 2 1/2 months' rest without therapy. This period was followed by extrapulmonary spread (severe arthritis of the elbow) and recurrence of pulmonary tuberculosis. The tubercle bacilli were sensitive to all the drugs so far employed. Renewed and lasting control of the infection was achieved only by continuous administration of steroids (prednisolone 10 mg twice daily) in conjunction with an unconventional antibiotic regimen consisting of amikacin, protionamide, terizidone, clarithromycin and sparfloxacin for some five months. Because of an episode of cerebral convulsions during treatment of cytomegalovirus retinitis with ganciclovir, the terizidone was discontinued (it was suspected of interacting with ganciclovir). The patient has had no more fits and sputum culture has remained negative for six months.

AIDS-Related Opportunistic Infections↗
PubMed1994

Adhesion molecules in lung diseases.

The human body possesses highly specialized cellular defense mechanisms that, when activated pathologically, can induce a number of immunologic disorders. For a normal cellular immune response, the following conditions must be fulfilled: (1) accumulation of white blood cells, (2) their diapedesis through the vessel walls of the inflammatory area affected by an injurious agent, and (3) normal cellular effector functions in the tissue. This cascade of inflammatory processes has recently been shown to be regulated by a group of molecules that are termed adhesion molecules and consist of three subfamilies: selectins, the immunoglobulin supergene family, and integrins. The cellular functions influenced by adhesion molecules include, among others, cytotoxic T-cell responses, CD4-dependent activation of B lymphocytes by T lymphocytes, activation of granulocytes and macrophages, phagocytosis of opsonized particles by monocytes, macrophages, and granulocytes, antigen-presenting function of macrophages, their antibody-dependent cytotoxicity, initiation of a respiratory burst by white blood cells, and activation of fibroblasts. Studies performed in recent years have shown that pathogenetically relevant changes in the expression and function of adhesion molecules are involved in a variety of pulmonary diseases. These changes include the accumulation and activation of alveolar macrophages in smokers, experimentally induced bronchial hyperreactivity in bronchial asthma, accumulation of eosinophils in allergic rhinitis, bleomycin-induced pulmonary fibrosis, binding of viruses and bacteria to respiratory mucosa, and various mechanisms of acute damage to pulmonary parenchyma. Though their role in tumor development is still unclear, adhesion molecules are obviously involved in determining the route and organotropism of metastases. Further studies of the function of adhesion molecules in pulmonary diseases will contribute to our understanding of the pathomechanisms of these diseases and, through the development of specific antibodies, may provide attractive new therapeutic approaches to problems for which treatment is not yet available.

Animals↗
PubMed1994

Surfactant protein A modulates release of reactive oxygen species from alveolar macrophages.

The production and release of reactive oxygen species (the respiratory burst) is a common metabolic pathway linked to several macrophage-related reactions. The most abundant surfactant protein A (SP-A) binds to alveolar macrophages (AM) through a specific surface receptor with high affinity. Because such binding might initiate or modulate the respiratory burst, we wanted to know whether and how SP-A affects the oxygen radical release from AM. To answer these questions, we measured the release of reactive oxygen species from rat AM under various in vitro conditions using enhanced chemiluminescence systems. We prepared SP-A from pulmonary surfactant isolated either from silica-treated rats or adult dogs. Resident AM were harvested from pathogen-free Wistar rats by lung lavage. Adhered and nonadhered AM were assessed on protein-free or protein-coated surfaces of 96-well microtiter plates. On protein-free surfaces, the sole addition of SP-A failed to induce measurable oxygen radical release from 2 x 10(5) adhered or nonadhered AM, while zymosan opsonized with SP-A induced a marked increase over control. On protein-coated surfaces, AM respond differently depending on the coated protein: on SP-A-coated surfaces, a dose-dependent enhancement of oxygen radical release with a mean effective concentration of approximately 1.15 micrograms/ml was found. No such enhancement was seen on plates coated with similar amounts of either human fibronectin or collagen, and the enhancement with serum albumin was not dose related. Our data demonstrate that SP-A only enhances oxygen radical release from AM if SP-A is fixed to zymosan or the surface of the reaction vial in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Simultaneous measurement of collagen type-VI-related antigen and procollagen type-III-N-propeptide levels in bronchoalveolar lavage.

Abnormal collagen metabolism is a hallmark of diffuse lung disease. Biochemical parameters which are correlated with collagen synthesis and degradation may be helpful to monitor fibrosis. In this study, we compared the sensitivity and specificity of procollagen type-III-N-propeptide (PIIINP) and collagen type-VI (C-VI) related antigen levels, as well as a ratio of both parameters (PIIINP/C-VI), in bronchoalveolar lavage fluid (BALF) from patients with diffuse and localized lung disease. We investigated 45 patients with diffuse lung disease (idiopathic pulmonary fibrosis (IPF), n = 21; sarcoidosis, n = 13; and lymphangitic carcinomatosis (LC), n = 11); 58 control subjects; and 92 patients with localized lung disease (bronchial carcinoma, n = 37; pulmonary tuberculosis, n = 31; and pneumonia, n = 24). C-VI and PIIINP were measured by immunoassay in concentrated BALF. Although the PIIINP and C-VI levels were increased in diffuse lung disease, the sensitivity of the individual parameters PIIINP and C-VI was low (IPF: PIIINP = 0.62, C-VI = 0.29; LC: PIIINP = 0.64, C-VI = 0.45; sarcoidosis: PIIINP = 0.69, C-VI = 0.15). When calculating the ratio of PIIINP/C-VI for each individual patient, we found a significant increase in this ratio in IPF (1.28 +/- 0.7), LC (2.34 +/- 1.2), and sarcoidosis (0.26 +/- 0.08) compared to both the controls (0.02 +/- 0.01) and other localized lung diseases (bronchial carcinoma 0.05 +/- 0.01; pulmonary tuberculosis 0.02 +/- 0.01), with the exception of pneumonia (0.18 +/- 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Comparative pharmacokinetics of the new oral cephalosporins.

The comparative pharmacokinetics of the new oral cephalosporins (ester and nonester types), together with that of the first generation carbacephem, loracarbef, are considered in healthy volunteers. Also in this review, pharmacokinetic and microbiological data are combined in order to predict the possible clinical efficacy of this group of agents. Despite apparent similarities in the structure of these agents, single dose studies have revealed marked differences in the pharmacokinetics of the oral cephalosporins. Multiple dose studies showed no evidence of accumulation with these agents. In the elderly, only minor changes in the pharmacokinetics of the oral agents were observed, and were insufficient to warrant dosage adjustment. Unlike that of the nonester compounds, the bioavailability of the ester cephalosporins is increased when they are administered after food. Variable effects are observed when the ester agents are coadministered with antacids or H2-antagonists; while the absorption of cefetamet pivoxil was unaffected by coadministered antacids or H2-antagonists, the absorption of cefpodoxime proxetil was reduced.

Administration, Oral↗