Search PubMed⌕ Search

Biomedical subjects

R Buhl

Publications and source records attributed to R Buhl.

At least 109 records · Page 6Linked to original sources

[Long-term therapy of alpha 1-antitrypsin-deficiency-associated pulmonary emphysema with human alpha 1-antitrypsin].

alpha 1-antitrypsin (alpha 1-AT) deficiency is a genetic disorder characterized by low serum levels of alpha 1-AT and a high risk of pulmonary emphysema at a young age. The resulting surplus of proteases, mainly of neutrophil elastase, can be balanced by i.v. augmentation with alpha 1-AT. However, it is not clear if affected patients benefit from long-term augmentation therapy and no long-term safety data are available. We examined 443 patients with severe alpha 1-AT deficiency and pulmonary emphysema receiving weekly i.v. infusions of 60 mg/kg body weight alpha 1-AT in addition to their regular medication. The progression of the disease was assessed by repeated lung function measurements, particularly the decline in forced expiratory volume in 1 second (delta FEV1). 443 patients with alpha 1-AT deficiency tolerated augmentation therapy well with few adverse reactions. The delta FEV1 in 287 patients with available follow-up data was 57.1 +/- 31.1 ml per year. Stratified for baseline FEV1, the decline was 35.6 +/- 21.3 ml in the 108 patients with an initial FEV1 < 30% and 64.0 +/- 26.4 ml in the 164 with 30% < FEV1 < or = 65% of predicted normal (p = 0.0008). The remaining 15 patients had an initial FEV1 > 65%. Long-term treatment with i.v. alpha 1-antitrypsin in patients with severe alpha 1-Pi deficiency is feasible and safe. The decline in forced expiratory volume in one second is related to the initial forced expiratory volume in one second as in alpha 1-antitrypsin deficient patients not receiving augmentation therapy.

Adult↗

[MR myelography in spinal canal stenosis].

PURPOSE: The purpose of this prospective study was to evaluate the clinical value of 3D-MR-myelography (3D-MRM) in comparison to myelography and intra-operative findings. MATERIAL AND METHODS: 25 patients with suspected lumbar spinal canal stenosis were studied via myelography and 3D-MRM (volume-data set, 3D-FISP sequence, TR 73 ms, TE 21 ms, flip angle 7 degrees, sagittal slices) besides the routinely acquired sagittal and axial T1- and T2-weighted images. Diagnoses were made by two radiologists and one neurosurgeon without knowing the clinical history and symptoms, in two separate sessions. Results were compared to intraoperative findings. RESULTS: 3D-MRM has the same diagnostic sensitivity (25/25 = 100%) as conventional X-ray myelography (25/25 = 100%) compared to intraoperative findings, but is not invasive and shows more diagnostic details than myelography. Especially in cases of high-grade spinal canal stenosis there is often a lack of intrathecal contrast medium distally of the stenosis. CONCLUSION: 3D-MRM is as good as conventional myelography in predicting intraoperative findings in patients with lumbar spinal canal stenosis. This new method is non-invasive and can be performed routinely on an outpatient basis.

Adult↗

Detection of normal mediastinal lymph nodes by ultrasonography.

PURPOSE: The detection by US (in contrast to CT) of lymph nodes of any size in the mediastinum is usually considered to be a pathological finding. The aim of this study was to find out whether it was possible to detect normal lymph nodes by high-resolution mediastinal US. MATERIAL AND METHODS: Six different mediastinal regions in 80 healthy asymptomatic volunteers and in 20 human cadavers were examined by means of US (with colour Doppler imaging) to assess US access to the respective regions and to demonstrate the number and size of detectable lymph nodes. All the cadaveric lymph nodes that were detected were examined histologically to exclude inflammatory or malignant infiltration. RESULTS: In almost all subjects, we obtained US access to the supra-aortic (100%), paratracheal (95%), prevascular (99%), and pericardial (98%) regions, and to the aorticopulmonary window (98%). US access to the subcarinal region was more difficult (75%). In the healthy subjects, lymph nodes were detected in the paratracheal region (in 35% of these subjects, mean lymph-node diameter 12 x 7 mm), in the aorticopulmonary window (45%, 14 x 8 mm), and in the subcarinal region (13%, 13 x 7 mm). In the cadavers, histologically normal lymph nodes were detected frequently in the paratracheal region (85%, mean size 11 x 6 mm) and in the aorticopulmonary window (90%, 11 x 5 mm). CONCLUSION: These results indicate that normal lymph nodes (and not only pathological lymph nodes) can be demonstrated by high-resolution mediastinal US.

Adult↗

Tumor necrosis factor-alpha modulates the selective interference of hypnotics and sedatives to suppress N-formyl-methionyl-leucyl-phenylalanine-induced oxidative burst formation in neutrophils.

OBJECTIVE: To clarify whether tumor necrosis factor (TNF)-alpha modulates the inhibitory effect of clinically applied hypnotics and sedatives on neutrophil function. DESIGN: Prospective, randomized, controlled, dose response, in vitro study. SETTING: A university research laboratory. SUBJECTS: Neutrophils from healthy human volunteers. MEASUREMENTS AND MAIN RESULTS: Neutrophils were primed by incubation with TNF-alpha (25 ng/mL) for 15 mins. Subsequently, TNF-alpha-primed neutrophils were incubated with two concentrations of commercially available drug preparations and drug-free solutions, respectively. The following commercially available preparations of hypnotics and sedatives as well as their corresponding drug-free solutions were tested: methohexital, thiopental, midazolam, diazepam, etomidate, and propofol. The production of oxygen radicals was initiated by adding N-formyl-methionyl-leucyl-phenylalanine (FMLP) 10(-7) mol/L and detected by luminol-enhanced chemiluminescence measurements for 15 mins. Within the range of therapeutic plasma concentrations, only thiopental, diazepam, and propofol suppressed chemiluminescence of unprimed neutrophils. Additionally, propofol alone suppressed TNF-alpha-primed neutrophils. Hypnotics and sedatives were unable to suppress oxygen radical production of TNF-alpha-primed neutrophils below the level of their control activity, measured in FMLP-induced unprimed neutrophils in the absence of the respective drug or drug-free solution. However, the effect of etomidate could not be evaluated secondarily to effects mediated by its drug-free solution. In a cell-free chemiluminescence system, thiopental and propofol demonstrated scavenging of oxygen free radicals. CONCLUSIONS: Priming with TNF-alpha counteracts the inhibitory effect by certain drugs for oxygen radical formation by FMLP-stimulated neutrophils. Thus, TNF-alpha plus FMLP mediate additive effects in stimulating oxygen radical formation in neutrophils. The following drugs dose-dependently interfere with these activating pathways: thiopental, diazepam, and propofol. Additionally, thiopental and propofol have efficient oxygen-scavenging properties and may attenuate radical-mediated tissue destruction in hyperinflammatory syndromes.

Free Radical Scavengers↗

Spirometric gated quantitative computed tomography of the lung in healthy smokers and nonsmokers.

RATIONALE AND OBJECTIVES: The authors investigated the influence of cigarette smoking on healthy, asymptomatic smokers and nonsmokers with the help of spirometric triggered quantitative computed tomography. In our prospective study, the authors compared conventional lung function parameters with the computed tomography values (lung attenuation, lung area). METHODS: The study group comprised 40 healthy volunteers consisting of 20 smokers and nonsmokers (20 females and 20 males). The corresponding groups have been matched concerning their age, height, body mass, (cigarette) pack years. Computer tomography scans were triggered at 35%, 50%, 70% and 95% of vital capacity at a defined apical and a basal level. RESULTS: Functional residual capacity (FRC), total lung capacity and airway resistance showed close correlations to lung parenchymal attenuation values especially at full inspiration and expiration. For example, the authors found a correlation coefficient of r = -0.845 (P < or = 0.001) concerning the FRC and lung attenuation values in the apical lung at 35% of vital capacity in male smokers. Male smokers proved to have a significantly higher pulmonary lung density at all inspiratory states than the other groups (P < or = 0.05; Student's t test). Although male smokers had a higher vital capacity they showed a smaller cross-sectional area increase of the lung during inspiration than nonsmokers. This phenomenon is a result of the decreasing compliance of the smoker's lung, due to small airways disease and hypoxic vasoconstriction. CONCLUSIONS: Spirometric-triggered quantitative computed tomography has proved to be a sensitive diagnostic device for the investigation of early pathomorphologic changes in healthy, asymptomatic cigarette smokers.

Female↗

Comparative loss of activity of recombinant secretory leukoprotease inhibitor and alpha 1-protease inhibitor caused by different forms of oxidative stress.

Secretory leukoprotease inhibitor (SLPI) and alpha 1-protease inhibitor (alpha 1-PI) are powerful antiproteases currently under investigation for their potential to protect the lung from neutrophil elastase (NE). The aim of this study was to determine whether the recombinant form of SLPI (rSLPI) and alpha 1-PI show different grades of loss of inhibitory activity when exposed to reactive oxygen metabolites. We incubated rSLPI and alpha 1-PI with N-chlorosuccinimide (NCS), chloramines, activated polymorphonuclear leucocytes (PMNs) and activated alveolar macrophages (AMs). Under all conditions evaluated, both antiproteases were partially inactivated. The resulting anti-NE activity of rSLPI was not significantly different from that of alpha 1-PI after exposure to NCS (p > 0.5), chloramines (p > 0.6), activated PMNs (p > 0.07) and activated AMs (p > 0.9). In conclusion, recombinant secretory leukoprotease inhibitor and alpha 1-protease inhibitor lose antineutrophil elastase activity to a similar extent when exposed to conditions that may be present in inflammatory lung disorders.

Animals↗

Short-term effects of regular salmeterol treatment on adult cystic fibrosis patients.

Cystic fibrosis (CF) is characterized by chronic lung inflammation leading to airways obstruction. Bronchodilators, particularly short-acting beta2-agonists, are, therefore, often used by CF patients. The aim of this study was to evaluate, prospectively, the effects of the long-acting beta2-agonist salmeterol in adult CF patients. Twenty six patients with CF (10 males and 16 females; mean age (+/-SEM) 28+/-2 yrs) with mild-to-moderate airways obstruction (baseline forced expiratory volume in one second/forced vital capacity (FEV1/FVC) 56+/-2%) were monitored in an open, cross-over trial for 4 weeks by means of peak expiratory flow rates (PEFR), self-recorded symptom scores and body plethysmography. During a 2 week run-in period, all patients continued their treatment, including regular short-acting beta2-agonists. In weeks 3 and 4, short-acting beta2-agonists were replaced by the long-acting beta2-agonist, salmeterol (50 microg b.i.d.). Salmeterol produced a significant increase in PEFR compared to the run-in period (morning 375+/-23 vs 332+/-23 L x min(-1), deltaPEFR +15.1+/-3.1%, p<0.003; evening 384+/-24 vs 349+/-24 L x min(-1), deltaPEFR +11.7+/-2.4%, p<0.04). Similarly, patients reported lower symptom scores, e.g. less dyspnoea during the day, fewer nocturnal awakenings, less intense cough, and fewer unscheduled puffs of short-acting beta2-agonists. Thus, the long-acting beta2-agonist salmeterol provided clinical benefit to a majority of adult cystic fibrosis patients with airways obstruction. These short-term results are promising enough to set up long-term controlled studies.

Administration, Inhalation↗

[Dura thickening adjacent to intracranial, para-dural space-occupying lesions in MRI. Histologic correlation].

PURPOSE: With intracranial tumors a flat, contrast-enhancing, probably dural structure adjacent to the tumor can occasionally be observed on gadolinium-DTPA enhanced MR images. Thers we have attempted to evaluate a tumor infiltration of these enhancement on MRI. MATERIAL AND METHODS: This study included 50 patients, 19 patients had a dural thickening at the tumor base (13 meningiomas and 6 metastases), while 31 patient did not (12 meningiomas and 19 metastases). Studies included plane T2-weighted spin echo (SE) images as well as T1-weighted axial, coronal, or sagittal plains with and without contrast agent. Histopathological examinations, were done on the tumor base adjacent to the dura mater. RESULTS: 7 of 12 meningiomas showed a meningeal thickening on MRI with histopathologically proven tumor infiltration as did also 5 of 6 metastases. But 3 of 12 meningiomas and 15 of 19 metastases without dural thickening at the tumor base also showed tumor invasion into the dura mater. CONCLUSION: MR imaging is still not able to determine whether or not there is a dural infiltration of the tumors base because there was no correlation between MR images and histopathologic results. In conclusion, metastases adjacent to the dura infiltrate the dura mater in a higher percentage than meningiomas.

Aged↗

Use of secretory leukoprotease inhibitor to augment lung antineutrophil elastase activity.

Physiologically, secretory leukoprotease inhibitor (SLPI) is the major antiprotease of the epithelium of the upper respiratory tract providing protection against neutrophil elastase (NE). The recombinant form of SLPI (rSLPI) has several advantages compared with alpha 1-antitrypsin that make it interesting as potential therapy. In vitro, rSLPI proves to be an excellent inhibitor of NE. When administered as an aerosol in vitro and in vivo, the structure and function of rSLPI remain intact. Using the aerosol route, the half-life of rSLPI in respiratory epithelial lining fluid is 12 h; thus, giving it twice daily should guarantee satisfactory levels in the lung. Following inhalation, rSLPI moves from the epithelium in an intact form into the interstitium of the lung. Following on from these in vitro and in vivo experiments, a short-term study in patients with cystic fibrosis was performed with aerosolized rSLPI. Promising results relative to NE level reduction and the consequences for the inflammatory process in the bronchi were achieved. rSLPI not only induced an increase of the anti-NE protective screen, but also improved the antioxidant protection by raising glutathione levels in the lung in sheep. rSLPI may therefore provide a unique opportunity for protecting the lung from the damage caused by inflammatory processes by giving a single drug.

Animals↗

Oxidant-protease interaction in the lung. Prospects for antioxidant therapy.

In inflammatory lung disorders, oxidants and proteases complement each other in their potential to destroy lung parenchyma. It is therefore rational to combine therapeutic strategies aimed at augmenting the antiproteolytic defenses of the lung in diseases such as emphysema with antioxidant strategies. In the healthy lung, the oxidant burden is balanced by the local antioxidant defenses. However, both an increased oxidant burden and/or decreased antioxidant defenses may reverse the physiologic oxidant-antioxidant balance in favor of oxidants, leading to lung injury. This concept points to an obvious therapeutic strategy: augmentation of the antioxidant screen of the lung to prevent oxidant-mediated tissue damage. Studies using reduced glutathione (GSH), the major pulmonary antioxidant, as a model therapeutic agent demonstrated that GSH can be administered directly to the respiratory epithelial surface by aerosol and is fully functional as an antioxidant both in vitro and in vivo. In pulmonary diseases such as idiopathic pulmonary fibrosis or following HIV infection, GSH aerosol therapy not only normalized deficient pretherapy GSH levels in the lung, but was capable of favorably influencing cellular events such as oxidant release by pulmonary inflammatory cells. The same was true for oral antioxidant therapy with N-acetylcysteine, a glutathione precursor. These results suggest that it is possible to use antioxidants to reverse the imbalance between oxidants and antioxidants at the site of oxidant injury to prevent the progressive tissue damage in lung disorders characterized by high oxidant states. Antioxidants, alone and in combination with antiproteases, merit further long-term studies for clinical therapy.

Acetylcysteine↗

Longterm efficiency of high dose inotropic support in an infant after repair of Fallot's tetralogy.

A 23 month old boy with highly symptomatic tetralogy of Fallot (TOF) underwent repair. Inspite of cold Bretschneider cardioplegic solution twice the heart was beating soon after application of the cardioplegic solution each time. Soon after transfer to the intensive care unit the patient developed low cardiac output (LCO). The following days high doses of inotropic support ware necessary to maintain sufficient arterial pressure. The dosages of dobutamine (up to 49 micrograms/kg/min); norepinephrine (up to 5.28 micrograms/kg/min, and epinephrine (up to 16 micrograms/kg/min), respectively, were twice and three times as high as common maximum recommendations. After having recovered from acute renal failure requiring hemodialysis from the 5th to the 37th postoperative day the child was discharged 9 weeks after the intervention. The very unusual and interesting course of this boy is described and the form and grade of the inotropic support is discussed.

Acute Kidney Injury↗

[Regulation of glutathione level in venous plasma and aqueous humor in cataracta senilis provecta].

UNLABELLED: Glutathione is a major component of the mechanisms protecting the eye against oxidants. To analyse the functional status and the regulation of the glutathione system in the eyes of patients with advanced cataract, glutathione concentrations were quantified in venous plasma and aqueous humor. METHODS: In all, 42 patients with advanced cataract (29 women, 13 men; mean age (+/- SEM) 70 +/- 2 years; vision < or = 0.3) were evaluated. Aqueous humour and venous plasma were obtained at the beginning of cataract surgery. RESULTS: Levels of total glutathione [reduced (GSH) + oxidized glutathione (GSSG)] in plasma were 2.34 +/- 0.23 microM. There was 2.08 +/- 0.15 microM in the reduced form and 0.27 +/- 0.17 microM oxidized glutathione, which means that 94.7 +/- 2.1% of the total glutathione was GSH, the form fully functional as an antioxidant. Levels of total glutathione in the aqueous humor were 1.2 +/- 0.16 microM, i.e. 54.5 +/- 4.8% of plasma levels. Surprisingly, the percentage of GSSG in aqueous humor (0.24 +/- 0.07 microM, 31 +/- 10.5% of the total glutathione) was much higher than that in plasma (P < 0.001). The correlation between glutathione concentrations in plasma and aqueous humor was on the borderline of significance (rs = 0.32, P < 0.04). CONCLUSION: The proportion of oxidized glutathione is higher in aqueous humor than in plasma of patients with advanced senile cataracts, indicating increased oxidant stress in the eye. Further, the regulation of the glutathione system in the eye, at least in aqueous humor, is dependent on plasma glutathione levels. This correlation reflects the importance of sufficient glutathione levels in venous plasma and suggests the possibility of modulating the glutathione system in the eye via manipulation of plasma glutathione levels.

Aged↗