Tumor classification by gene expression profiling

The considerable "algorithmic complexity" of biological systems requires a huge amount of detailed information for their complete description. Current high-throughput technology such as microarrays is generating an overwhelming amount of data of biological systems at the molecular and cellular level. To adequately organize, maintain, analyze and interpret this deluge of information the adaptation of existing and the development of new computational methodologies and tools is required. The principal approach to analyzing and interpreting biological data is to abstract them into logical structures that support and incrementally promote the development of a more general conceptual framework for characterizing, explaining, and predicting processes in living systems. Cluster analysis refers to a computing methodology that discovers and describes meaningful patterns or structures in data. Generally, cluster algorithms are governed by a learning-by-observation process. A plethora of specific algorithms has been suggested in the literature. In the context of microarray gene expression profiling of tumors, this work describes a comparative study of five clustering methods.

Relapsing polychondritis in childhood--case report and short review

Relapsing polychondritis (RP) is a disease of unknown etiology and it is characterized by inflammation of the cartilage. While the clinical picture of RP in adults is well described, RP in childhood is poorly documented. We describe a young girl presenting with acute dyspnea, stridor and polyarthritis. The diagnosis of RP was made 2 years after first presentation, when auricular chondritis occurred. Based on a MEDLINE search, reports on RP in childhood were reviewed. The frequency of chondritis and systemic manifestations of RP in children was compared to data in adults and found to be very similar. RP in childhood can be a life-threatening and debilitating disease.

Simultaneous arterial calcium dynamics and diameter measurements: application to myoendothelial communication

The goal of the present study was to analyze the intercellular calcium communication between smooth muscle cells (SMCs) and endothelial cells (ECs) by simultaneously monitoring artery diameter and intracellular calcium concentration in a rat mesenteric arterial segment in vitro under physiological pressure (50 mmHg) and flow (50 microl/min) in a specially developed system. Intracellular calcium was expressed as the fura 2 ratio. The diameter was measured using a digital image acquisition system. Stimulation of SMCs with the alpha(1)-agonist phenylephrine (PE) caused not only an increase in the free intracellular calcium concentration of the SMCs as expected but also in the ECs, suggesting a calcium flux from the SMCs to the ECs. The gap junction uncoupler palmitoleic acid greatly reduced this increase in calcium in the ECs on stimulation of the SMCs with PE. This indicates that the signaling pathway passes through the gap junctions. Similarly, although vasomotion originates in the SMCs, calcium oscillates in both SMCs and ECs during vasomotion, suggesting again a calcium flux from the SMCs to the ECs.

Antileukotrienes in asthma: present situation

Leukotrienes are key mediators in asthma. Over the last 5 years, several antileukotrienes, including three receptor antagonists (montelukast, pranlukast and zafirlukast) and one 5-lipoxygenase inhibitor (zileuton), have been marketed and, to date, this class of drugs is being used widely. Still, their definite place in the asthma treatment algorithm is not yet established. These novel drugs have not yet all been evaluated in the same depth, but they have all been shown to possess anti-inflammatory properties and to be effective in chronic asthma treatment. Zafirlukast and montelukast are particularly efficacious in exercise-induced asthma and zileuton appears valuable for treating aspirin-intolerant asthmatics. Clinical comparisons to other anti-asthma drugs are still sparse. The corticosteroid-sparing effect of antileukotrienes is fairly well established except for zileuton, even though this drug has been evaluated most thoroughly in terms of its anti-inflammatory effects. Montelukast is the antileukotriene most extensively evaluated in children and zafirlukast has recently been approved for use in children in the USA, although not yet in Europe. Therapeutic regimes are quite variable depending on the drug, but all of the antileukotrienes marketed to date are taken orally; hence, compliance is usually greater than that with inhaled medication. Response to antileukotrienes appears to depend on the individual patients' characteristics, in particular on genetic polymorphisms related to leukotriene metabolism. All drugs of this class are well tolerated and only in the case of zileuton is there potential for hepatic adverse effects. The diagnosis of Churg-Strauss syndrome made among patients taking antileukotrienes seems to be more related to the withdrawal of corticosteroids than to the antileukotrienes themselves.

A nationwide survey in Germany on fatal asthma and near-fatal asthma in children: different entities?

In adults fatal and near-fatal asthma have similar clinical characteristics. Therefore, near-fatal asthma in adults can be used as a model for fatal asthma. A nationwide study on fatal and near-fatal asthma in children <16 yrs was performed in order to assess whether, as in adults, near-fatal asthma can be used as a model for fatal asthma. From 1996 to 1998, all paediatric hospitals and paediatric pulmonologists in Germany were asked to report cases of fatal asthma and near-fatal asthma to a central survey unit (Erhebungseinheit für seltene pädiatrische Erkrankungen in Deutschland (ESPED)) on a monthly basis. All reports were followed by detailed questionnaires. Sixteen fatal and 45 near-fatal asthma cases were analysed. Fatal asthma patients were older than near-fatal asthma patients. Respiratory tract infections were frequently reported only in near-fatal asthma (47 versus 0%). The proportion of cases with rapid-type onset (duration of symptoms < or =1 h) was higher in fatal asthma (53 versus 14%). Long-term regular treatment with short acting beta2-agonists was common in both groups, but the use of concomitant inhaled corticosteroids was significantly lower in fatal asthma cases. A high proportion of poor compliance was observed in both groups. As fatal and near-fatal asthma differ significantly in important clinical aspects, analysis of near-fatal asthma might be of limited value in elucidating the causes of fatal asthma in children.

[Effect of glass ceramics on bone regeneration in calvarial defects. Experimental study]

INTRODUCTION

The purpose of this study was to investigate the influence of different compositions of resorbable porous glass ceramics on their performance in calvarial defects.

MATERIAL AND METHODS

Full-thickness defects (8.1 mm diameter) were made in the calvaria of 75 adult Sprague-Dawley rats. Pellets of porous glass ceramics were inserted press-fit into 60 defects. Four different materials were implanted into each of 15 animals: (1) glass ceramic with a high relation of calcium to phosphate containing silicate; (2) glass ceramic with a high relation of calcium to phosphate without silicate; (3) glass ceramic with a low relation of calcium to phosphate without silicate; and (4) glass ceramic with a low relation of calcium to phosphate containing silicate. Five implants of each group were evaluated by fluorescence microscopy and light microscopy after 6, 13, and 26 weeks.

RESULTS

Those glass ceramics with a high relation of calcium to phosphate showed formation of new bone entering the defect from the margins as soon as 6 weeks postoperatively. After 26 weeks, the formation of new bone reached the center of the defect. In the other glass ceramics, the formation of unmineralized osteoid was visible entering the defect from the margins. No mineralization was seen 26 weeks postoperatively. There was no significant difference between glass ceramics containing silicate and those free of silicate.

CONCLUSIONS

Bioresorbable glass ceramics may be of benefit in the treatment of osseous defects without functional loading.

Anti-neutrophil cytoplasmic antibodies directed against the bactericidal/permeability-increasing protein (BPI) in pediatric cystic fibrosis patients do not recognize N-terminal regions important for the anti-microbial and lipopolysaccharide-binding activity of BPI

This study was performed to examine the prevalence and clinical correlates of bactericidal/permeability-increasing protein anti-neutrophil cytoplasmic antibodies (BPI-ANCA) in pediatric cystic fibrosis (CF) patients and to elucidate their possible role in CF pulmonary pathology. Sera of 27 CF patients were tested for ANCA by indirect immunofluorescence (IFT) and by enzyme-linked immunosorbent assay (ELISA) for ANCA sub-specificities. BPI-ANCA were examined by using standard ELISA for BPI, lipopolysaccharide-binding protein (LBP), and BPI/LBP fusion proteins to epitope map the main binding sites and look for cross-reactivity with LBP. Pulmonary function and serum concentrations of total immunoglobulin G (IgG) were measured and infections were diagnosed. In addition, release of reactive oxygen species (ROS) by neutrophil granulocytes was measured after stimulation with monoclonal BPI-ANCA. Using IFT, two patients showed atypical ANCA staining, six patients exhibited perinuclear ANCA staining, and no cytoplasmic ANCA staining was detected. Of 27 patients, 13 (48%) were BPI-ANCA (IgG) positive, and three were also immunoglobulin A (IgA) BPI-ANCA positive; one patient had ANCA against lactoferrin; and no proteinase 3 ANCA was detected in any of the patients. All BPI-ANCA bound to the C-terminal region of the molecule; none bound to the N-terminus or to LBP. There was no significant correlation between clinical data and the occurrence of BPI-ANCA in this cross-sectional study. Release of ROS from granulocytes was induced by monoclonal BPI-ANCA. Activation of neutrophils and possible modulation of BPI-mediated opsonophagocytosis and disposal of Gram-negative bacteria and lipopolysaccharides by BPI-ANCA raise the possibility that they contribute to pulmonary pathology in pediatric CF patients but intervention longitudinal studies in large groups of patients are needed to establish a causative association.

Transarterial chemoembolization for hepatocellular carcinoma: volumetric and morphologic CT criteria for assessment of prognosis and therapeutic success-results from a liver transplantation center

PURPOSE

To evaluate the prognostic value of volumetric computed tomography (CT) for therapy control in patients treated with repeated transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Eighty-five patients with histologically proved HCC underwent 182 TACE procedures with 50 mg/m(2) doxorubicin hydrochloride, 50 mg/m(2) cisplatin, 10 mL/m(2) iodized oil, and amilomer microspheres. The volumes of liver and tumor were measured with a region-of-interest CT technique. Iodized oil retention was estimated with CT performed 24-48 hours after treatment.

RESULTS

Tumor volume expressed as a percentage of liver volume was less than 5% in 26, less than 15% in 33, and 15% or greater in 26 patients. The overall 1-year survival rate was 57.6% (mean, 534 days; median, 428 days). There was a statistically significant prolongation of survival when the tumor volume was less than 200 mL (P <.02) and less than 5% of the liver volume (P <.01). Complete (>/=75%) and good (50%-74%) iodized oil retention raised the median survival significantly (P <.001 and P <.07, respectively). Significantly reduced survival correlated with diffuse tumor growth pattern (P <.05) and presence of more than nine lesions (P <.03).

CONCLUSION

TACE resulted in significant prolongation of survival in patients with tumor volumes of less than 200 mL, tumor-to-liver volume ratios of less than 5%, and iodized oil retention greater than or equal to 75%.

ENVIRONMENTAL AUDITING: Environmental Auditing in Hospitals: First Results in a University Hospital

/ While medical audit in infection control today is one important element in the quality assurance of health care, environmental auditing, approved in 1993 by the Council of the European Communities for the industrial sector, so far has not been used as a tool to control and reduce environmental pollution caused by medical care. The aim of this study was to investigate whether environmental auditing according to the European Eco-Management and Audit Scheme (EMAS) can be implemented in hospitals as a process of improvement in protection of the environment. In a prior publication the methodological issues and the organizational steps that had to be taken were described. An environmental review of the activities of the Freiburg University Hospital and an ecoanalysis of the input and output were performed. The results of this analysis, published in an environmental report, provide a fundamental data set for the consumption of energy, water, materials, and the burdens of major pollutants and waste. Regarding the organizational structure of the hospital, the first steps towards an integrating environmental management system as demanded by EMAS could be taken. Beside supporting advantages, e.g., improvement of environmental safety, public image and staff contentment, and potential economic benefits such as less cost to be paid for energy and water consumption, there are important restrictions of environmental auditing in hospitals. Examples are the lack of basic environmental data, staff motivation (especially of physicians), cooperation of the organizational substructures, and funds for prefinancing urgently needed improvements in ecology. Based on the study findings, a textbook on environmental auditing in hospitals, including checklists covering all important environmental objectives, has been published to support hospitals in their efforts to achieve an optimized and sustainable practice of providing health care.

Detection of the ETV6-NTRK3 chimeric RNA of infantile fibrosarcoma/cellular congenital mesoblastic nephroma in paraffin-embedded tissue: application to challenging pediatric renal stromal tumors

We report the development of a reverse transcriptase polymerase chain reaction assay that reliably detects the ETV6-NTRK3 chimeric RNA characteristic of infantile fibrosarcoma and the cellular variant of congenital mesoblastic nephroma (CMN) in formalin-fixed, paraffin-embedded tissue blocks. The 188 base pair polymerase chain reaction fusion product was detected in 11 of 12 cases of cellular CMN from which a larger sized control RNA band could be amplified, and even in 7 of 8 cases in which the control band was not detectable. A variety of other tumors that are in the histologic differential diagnosis of cellular CMN yielded negative results, including four classic CMNs, four rhabdoid tumors of the kidney, and four clear cell sarcomas of the kidney, confirming the assay's specificity. We further demonstrate the assay's utility by illustrating two cases of molecularly confirmed cellular CMN that mimicked rhabdoid tumor and clear cell sarcoma of the kidney. In contrast to previous reports, five mixed CMNs that had both classic and cellular areas all lacked the ETV6-NTRK3 fusion transcript. These results suggest that cases morphologically defined as mixed CMN may represent a mixed group of genetically distinct entities.

[Multi-sequential arterial chemoembolization of advanced hepatocellular carcinomas: computerized tomography follow-up parameters for evaluating effectiveness of therapy]

PURPOSE

An evaluation of clinical and computed tomography parameters for the transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC).

MATERIAL AND METHODS

Retro- and prospective analysis of 123 TACE procedures in 37 patients (mean age: 63.3 years).

RESULTS

Overall mean survival rate for all treated patients was 785 days with a mean value of 387 days. The 1 year survival rate was 62%. Quantitative tumor volumetry revealed a significant difference in survival rate with a mean value of 678 days for patients with a reduction of tumor volume between 0 and 50%, 976 days for a volume reduction of 51-100% and 277 days for an increase in tumor volume during therapy. Patients with a high lipiodol retention presented improved survival data (902 days) versus patients with a low lipiodol retention (513 days). Homogeneous retention of lipiodol was a positive factor on survival as compared to an inhomogenous form of retention.

CONCLUSION

In patients with a positive therapy response after TACE the prognosis can be improved by repeated embolization.

Liquid chromatography/electrospray tandem mass spectrometry method for the quantitation of fosinoprilat in human serum using automated 96-well solid-phase extraction for sample preparation

A sensitive, specific, accurate and reproducible liquid chromatography/electrospray tandem mass spectrometry method was developed and validated for the quantitation of fosinoprilat in 0.2 mL of human serum. The method employed acidification (with pH 4.0 sodium acetate buffer) of the serum samples to minimize the hydrolysis of the prodrug fosinopril to fosinoprilat prior to purification by automated 96-well solid-phase extraction. The required chromatographic separation of fosinoprilat and fosinopril was achieved isocratically on a Luna C8 analytical column (2 x 50 mm, 3 microm). The total run time was 2 min. The mobile phase contained methanol and water with 10 mM ammonium acetate. Detection was by positive ion electrospray tandem mass spectrometry. The standard curve, which ranged from 2.00 to 500 ng/mL, was fitted to a 1/x(2) weighted linear regression model. Fosinoprilat quality control (QC) samples used to determine the accuracy and precision of the method were prepared in human serum at concentrations of 5.00, 200, 400 and 1000 ng/mL. The assay accuracy was within 8% (dev). The intra- and inter-assay precisions were within 6 and 3% (RSD), respectively. Fosinopril QC samples used to gauge the rate of hydrolysis of fosinopril to fosinoprilat during the assay procedure were prepared in human serum at 500 ng/mL. The hydrolysis of fosinopril to fosinoprilat was </=1%. This degree of conversion would cause little error in the analysis of post-dose serum samples since such samples are known to contain low levels of the prodrug compared with the drug.

New perspectives for asthma treatment: anti-leukotriene drugs

Leukotrienes are synthesized by different cells, including eosinophils, neutrophils, basophils, lymphocytes, macrophages, and mast cells. Cysteinyl leukotrienes (LTC4, LTD4, and LTE4) are the most important leukotrienes in the pathogenesis of asthma. Pharmacologically, there are two different ways of blocking the action of leukotrienes: inhibiting their production by blocking 5-lipoxygenase or its activating protein, 5-lipoxygenase-activating protein (FLAP), (inhibitors) or by blocking their receptors (antagonists). The available antagonists are, for the moment, directed against the one receptor demonstrated to play a role in asthma symptoms, CysLT1, and they act in a competitive way. The only marketed 5-lipoxygenase inhibitor is zileuton (Zyflo). CysLT1 antagonists, currently on the pharmaceutical market in some countries, are zafirlukast (Accolate), pranlukast (Ultair, Onon), and montelukast (Singulair). Undoubtedly, drugs acting on leukotrienes constitute a new pharmacologic class in the therapeutic armamentarium for the management of asthma. From the pediatric point of view, montelukast is currently the most interesting drug of the group to date because of published trials in patients as young as 6 yr of age. At present, zafirlukast is only approved for use in patients 12 yr of age and older, although we understand that applications are likely to extend the age range into childhood shortly. However, more experience is necessary to establish a definite place for both leukotrienes in the step-by-step asthma treatment. New comparative studies (with sodium cromoglycate and inhaled steroids), which will probably be published in the near future, as well as studies on the use of montelukast in the treatment of children under 6 yr of age will add crucial information to our knowledge, and help to identify an appropriate use in the therapeutic algorithm. Montelukast will not be a substitute for inhaled corticosteroids or beta-agonists, although it may act as a 'sparing drug' (which might help tapering of steroids in some instances). Its role in exercise-induced asthma seems promising. Although its more widespread use could highlight low-frequency adverse effects, its apparent excellent tolerability is an additional advantage for the drug. Patients' preference for a twice-daily dosage over the inhaled medication, resulting in a better compliance, is relatively well established, at least for zafirlukast in adults, and these findings can probably be extended to montelukast, which only requires once-daily dosing in children.

Proteinase 3, a potent secretagogue in airways, is present in cystic fibrosis sputum

We evaluated the roles of proteinase 3 (PR3) and human neutrophil elastase (HNE), two neutrophil serine proteinases in the mechanisms leading to airway inflammation and hypersecretion in cystic fibrosis (CF). Using specific enzyme-linked immunosorbent assay (ELISA), we found higher levels of PR3 than HNE in sputum from CF patients. Using two inhibitors, ICI (Imperial Chemical Industries) 200,355 (which inhibits both HNE and PR3) and secretory leukoproteinase inhibitor (SLPI) (which inhibits only HNE), we showed that PR3 was enzymatically active in sputum, and its activity, as assessed by SLPI-resistant serine proteinase activity, correlated highly with its antigenic concentration measured by ELISA. Interestingly, sputum pellet-associated serine proteinase activity was mostly due to HNE. PR3 purified from neutrophil azurophil granules triggered airway gland secretion, as measured by the release of radiolabeled molecules from cultured bovine tracheal serous cells pulse-labeled with Na235SO4. This secretory activity was inhibited by ICI 200,355. PR3 concentration in CF sputum was highly correlated with taurine concentration, a reliable marker of airway inflammation and respiratory scores (e.g., FEV1%), whereas no significant correlation was observed with HNE. We verified that Pseudomonas aeruginosa proteinases did not interfere with the assessment of PR3 and HNE. Indeed, the PR3/HNE ratio was greatest in patients chronically infected by P. aeruginosa. We suggest that PR3 may play a role in the hypersecretory process that is characteristic of CF.

Adrenal-dependent modulation of the catalytic subunit isoforms of the Na+-K+-ATPase in aorta

Na+-K+-ATPase gene expression and activity were studied in aortas from adrenalectomized (ADX) rats and ADX rats with deoxycorticosterone supplement (ADX-DOCA). Northern analysis of RNA from ADX rats revealed a significant decrease in alpha2-mRNA levels (38.5 +/- 8.3% of control, P < 0.01) that was prevented by DOCA (P < 0.05). A decrease to 55.8 +/- 7.7% in alpha2-isoform protein was observed 8 days after adrenal removal (P < 0.05); DOCA reversed this effect (90.8 +/- 10.5%). Adrenalectomy induced a decrease of 68.5 +/- 4.5% in beta1-mRNA (P < 0.01) and 52.7 +/- 8.3% in ADX-DOCA rats (P < 0.01). Also, a reduction in beta1-isoform protein that was not prevented by DOCA was detected after adrenalectomy (47.1 +/- 11%, P < 0.01). In contrast, no differences in alpha1-mRNA or -protein levels were observed. Vascular sodium pump activity was reduced to 59.8 +/- 4.6% of control values after adrenalectomy (P < 0.01); this reduction was reversed by DOCA. Our data indicate that corticosteroids regulate Na+-K+-ATPase isoform expression and activity in vascular tissue in vivo, suggesting a mineralocorticoid-dependent modulation of alpha2-Na+-K+-ATPase gene expression in aorta, with beta1-isoform expression dependent on the presence of glucocorticoids.

Transacromial approach to obtain fusion of unstable os acromiale

The purpose of this study was to identify possible causes for the low union rate for surgically stabilized os acromiale. Between February 1990 and November 1995, fusion of an os acromiale was attempted in 15 shoulders in 12 patients at our institution. All patients were men. The mean age was 54 years (range 37 to 63 years). All shoulders had an os mesoacromiale considered too large for simple resection. An associated lesion of the rotator cuff ranging from partial-to full-thickness tear was present in all patients. Eleven had an unfused acromial epiphysis in both shoulders. Two different surgical approaches were used. Seven shoulders were approached through an anterior deltoid-off approach, thus potentially devascularizing the os acromiale. Eight shoulders were approached transacromially, preserving the deltoid origin and hence the terminal branches of the thoracoacromial artery. The technique of internal fixation (tension band wiring) was the same for both groups. The mean follow-up was 44 months (range 13 to 72 months). Union, as demonstrated by axial radiographic views, occurred in 3 out of 7 cases with a devascularized os acromiale and in 7 out of 8 shoulders with a perfused os acromiale (P = .017), respectively. Patients with a united os acromiale had a significantly better functional outcome as measured by the Constant score (P = .0169). In conclusion, aiming at a stable fusion of a sizable and hypermobile os acromiale is probably desirable because it enhances the overall functional result. Obtaining consolidation was possible when the vascularity of the acromial epiphysis was respected.

The human WD repeat protein WAIT-1 specifically interacts with the cytoplasmic tails of beta7-integrins

Integrins of the beta7 subfamily, alpha4 beta7 and alphaE beta7, contribute to lymphocyte homing and to the development of protective or autoreactive immune responses at mucosal sites. The beta subunits of integrins are considered important for regulation of stimulated cell adhesion and adhesion-dependent signal transduction. Using a yeast interaction trap screen, a human WD repeat protein, termed WAIT-1, was isolated that interacts with the integrin beta7 cytoplasmic tail and is homologous to mouse EED and Drosophila ESC proteins. WAIT-1 also binds to the cytoplasmic domains of alpha4 and alphaE but not to those of integrin beta1, beta2, and alphaL subunits. Association of WAIT-1 and beta7-integrin was confirmed by coprecipitation from transiently transfected 293 cells. The binding site for WAIT-1 was mapped to a short membrane-proximal region of the beta7 cytoplasmic tail with Tyr-735 being of critical importance. Northern blot analysis revealed multiple WAIT-1-related transcripts with differential expression in circulating leukocytes, tissue-resident cells of diverse origin, and lymphoid malignancies. These results suggest that WAIT-1, together with the recently identified RACK1, may define a novel subfamily of WD repeat proteins that interact with distinct subsets of integrin cytoplasmic tails and may act as specific regulators of integrin function.

NPY Y1 antagonists: structure-activity relationships of arginine derivatives and hybrid compounds with arpromidine-like partial structures

Previously, omega-guanidino- and omega-aminoalkanamides, structurally derived from arpromidine-like histamine H2 receptor agonists, were reported as novel neuropeptide Y Y1 antagonists. Regardless of the backbone, they resemble BIBP 3226, an argininamide with high NPY Y1 receptor affinity and selectivity, with respect to nature and arrangement of the 'terminal' diaryl, guanidine, and hydroxyphenyl groups. Hybrid compounds were synthesized combining the argininamide backbone of BIBP 3226 or partial structures derived from the C-terminal dipeptide of NPY with characteristic substructures of arpromidine- or amide-type NPY antagonists. Additionally, some analogs of BIBP 3226 with reduced flexibility were prepared. Structure-activity relationships indicate that, in contrast to alkanamides, homologs and/or isomers of BIBP 3226 with vicinal arrangement of the phenyl rings have decreased Y1 antagonistic activity (Ca2+-assay in HEL cells). Replacement of the hydroxybenzyl group by an imidazole ring further decreases activity. It is concluded that the binding sites of NPY antagonists with one and with two basic groups are not identical. Analogs with a rigid tetrahydro-2-benzazepine or an indan group in place of the benzyl moiety in BIBP 3226 are active, indicating the role of the OH group and supporting the model proposed for the interaction of BIBP 3226 with the Y1 receptor.

Chloride conductance and Pi transport are separate functions induced by the expression of NaPi-1 in Xenopus oocytes

Expression of the protein NaPi-1 in Xenopus oocytes has previously been shown to induce an outwardly rectifying Cl- conductance (GCl), organic anion transport and Na+-dependent Pi-uptake. In the present study we investigated the relation between the NaPi-1 induced GCl and Pi-induced currents and transport. NaPi-1 expression induced Pi-transport, which was not different at 1-20 ng/oocyte NaPi-1 cRNA injection and was already maximal at 1-2 days after cRNA injection. In contrast, GCl was augmented at increased amounts of cRNA injection (1-20 ng/oocyte) and over a five day expression period. Subsequently all experiments were performed on oocytes injected with 20 ng/oocytes cRNA. Pi-induced currents (Ip) could be observed in NaPi-1 expressing oocytes at high concentrations of Pi (>/= 1 mm Pi). The amplitudes of Ip correlated well with GCl. Ip was blocked by the Cl- channel blocker NPPB, partially Na+-dependent and completely abolished in Cl- free solution. In contrast, Pi-transport in NaPi-1 expressing oocytes was not NPPB sensitive, stronger depending on extracellular Na+ and weakly affected by Cl- substitution. Endogenous Pi-uptake in water-injected oocytes amounted in all experiments to 30-50% of the Na+-dependent Pi-transport observed in NaPi-1 expressing oocytes. The properties of the endogenous Pi-uptake system (Km for Pi > 1 mM; partial Na+- and Cl--dependence; lack of NPPB block) were similar to the NaPi-1 induced Pi-uptake, but no Ip could be recorded at Pi-concentrations </=3 mM. In summary, the present data suggest that Ip does not reflect charge transfer related to Pi-uptake, but a Pi-mediated modulation of GCl.

High-performance liquid chromatographic-electrochemical assay for the quantitation of BMS-181885 in monkey plasma

A high-performance liquid chromatographic-electrochemical assay was developed and validated for the quantitation of BMS-181885 (I), an anti-migraine agent, in monkey plasma. The assay involved a solid-phase extraction of I and BMY-46317 (internal standard; I.S.) on a 1-ml cyano cartridge using the automatic solid-phase extraction cartridge (ASPEC) system. Immediately following the conditioning of the cyano column (3 ml of methanol and 2 ml of 1% glacial acetic acid), plasma (0.25 ml) was loaded on to the column. The column was then washed with a 3 ml of 0.1 M ammonium acetate buffer (pH 6). The final elution of the analytes was performed using 2 ml of methanol. The eluate was then evaporated to dryness (gentle stream of nitrogen at 40 degrees C) and the residue was dissolved in the mobile phase and injected on to a YMC basic column (15 cm x 4.6 mm; 5 microm particle size) at a flow-rate of 1 ml/min. A mixture of 0.1 M ammonium acetate at pH 6-acetonitrile-methanol (70:20:10, v/v) was used as the mobile phase. Standard curves, with a lower limit of quantitation of 2 ng/ml of I were linear (r2> or =0.998; range: 2-50 ng/ml). Based on the analysis of the quality control (QC) samples, the assay was both accurate and precise. The stability of I was established following freeze-thaw cycles and storage at or below -20 degrees C. The extraction recovery of I from monkey plasma was about 82%. The validated assay method was applied to determine the pharmacokinetics of I in monkeys following a single 1 mg/kg intravenous dose.

Prospective, double-blind, placebo-controlled, multicentre study on the effect of high-dose, intravenous immunoglobulin in children and adolescents with severe bronchial asthma

OBJECTIVE

In order to study the effect of high-dose, intravenous immunoglobulin (i.v.IG) in severe childhood asthma, we investigated 31 children and adolescents (15 girls, 16 boys) aged 9-22 years (median age of 14 years) suffering from severe bronchial asthma.

METHODS

In a prospective, double-blind fashion, patients received either four doses of i.v.IG (1 g/kg body weight) or identical doses of intravenous human serum albumin. The first two doses were given on two consecutive days, followed by two further doses at 4 week intervals.

RESULTS

There was no statistical difference in the actively treated group when compared with the placebo group in symptom-score, bronchial hyperreactivity or peak-flow-variability. There was a trend for fewer total days of upper respiratory tract infections and also symptom-scores in the i.v.IG group but these did not reach statistical significance.

CONCLUSION

Our data indicate that treatment with i.v.IG in asthmatic children did not show a significant reduction in the incidence of upper respiratory tract infections, but the patients who did have upper respiratory infections in the i.v.IG-group appear to have less protracted infections. Severity and bronchial hyperreactivity do not seem to be affected by the treatment as performed in our study.

Effects of age, gender, and diurnal variation on the steady-state pharmacokinetics of BMS-181101, an antidepressant, in healthy subjects

OBJECTIVES

To investigate the effects of age, gender, and diurnal variation on the safety, tolerability, and steady-state pharmacokinetics of BMS-181101, an antidepressant, in humans.

METHODS

This was a multiple-dose parallel-design study in 51 healthy subjects (12 young and 12 elderly men and 12 young and 15 elderly women). Each subject received a 15 mg oral dose of BMS-181101 every 12 hours on days 1 through 6 and one dose on day 7. After the evening dose on day 6 and morning dose on day 7, serial blood samples were collected at specified times after administration. Plasma was analyzed for BMS-181101 with use of an HPLC method.

RESULTS

Male subjects tolerated BMS-181101 better than female subjects. The mean values for area under the plasma concentration-time curve over the dosing interval tau (AUC tau; 58.8 to 102.4 ng.hr/ml) and elimination half-life t1/2; 5.7 to 10.4 hours) for the elderly subjects were significantly greater than those for the young subjects (39.0 to 64.3 ng.hr/ml and 3.2 to 4.5 hours). The mean values for peak plasma concentration (Cmax; 14.7 to 25.2 ng/ml) and AUC tau (52.4 to 102.4 ng.hr/ml) for the women were significantly greater than those for the men (9.08 to 15.3 ng/ml and 39.0 to 73.6 ng.hr/ml). The mean values for Cmax (14.7 to 25.2 ng/ml) and AUC tau (54.8 to 102.4 ng.hr/ml) on the morning of day 7 were significantly greater than those after the evening dose on day 6 (9.08 to 17.3 ng/ml; 39.0 to 83.4 ng.hr/ml).

CONCLUSIONS

An initial lower dose or appropriate titration of daily doses of BMS-181101 may be necessary for the treatment of elderly and female subjects, and the pharmacokinetics of BMS-181101 exhibited significant diurnal effects.

Environmental auditing in hospitals: approach and implementation in an university hospital

Medical audit in infection control today is accepted as an important element in the quality assurance of health care. In contrast, environmental auditing, which was approved in 1993 by the Council of the European Communities for industry ("Eco-Management and Audit Scheme-EMAS), has not so far been used as a tool to control and reduce environmental pollution caused by medical care in hospitals. The aim of this study was to investigate, whether environmental auditing in hospitals is useful. This process should also be cost effective. In this paper, methodological and organizational issues are described. Initially an environmental review of activities at the University Hospital, Freiburg and an eco-analysis of the input and output were performed. The first results of the study and a critical discussion will be presented in another paper.

Effects of native and oxidation-resistant secretory leukoprotease inhibitor on cystic fibrosis sputum: inhibition of neutrophil elastase activity and of sputum-induced secretion from porcine tracheal submucosal glands

Because the antiprotease defense in cystic fibrosis (CF) airways is overwhelmed by neutrophil elastase (NE), substitution of antiproteases such as secretory leukoprotease inhibitor (SLPI) seems to be a reasonable therapeutic approach. Knowing, however, that native antiproteases may be liable to rapid inactivation by the locally abundant oxidants, we comparatively investigated the interactions of CF sputum with recombinant native SLPI (rSLPI) and its partially oxidation-resistant variant (rSLPI-242), respectively, to estimate their therapeutic potentials. NE activity in supernatants from diluted CF sputum samples was dose-dependently inhibited by both rSLPI and rSLPI-242, with comparable potency. Addition of the oxidant N-chlorosuccinimide resulted in significant superiority of rSLPI-242 over rSLPI. When fresh neutrophil-rich CF sputum was incubated with rSLPI and rSLPI-242, respectively, rSLPI-242 inhibited sputum NE activity significantly more potently than did rSLPI; addition of the antioxidant superoxide dismutase significantly improved the effect of rSLPI. Furthermore, secretion of radiolabeled macromolecules from porcine tracheal glands induced by purified NE or by CF sputum was inhibited dose-dependently by rSLPI and even better by rSLPI-242. We conclude that both rSLPI and rSLPI-242 effectively inhibit NE activity and NE-induced gland hypersecretion in vitro. In vivo effects of CF remain to be analyzed; an advantage of the partially oxidation-resistant rSLPI-242 can be expected.

Expression of the human MxA protein is associated with hyperphosphorylation of VSV P protein in human neural Cells

Constitutive expression of the type I interferon-inducible human cytoplasmic MxA protein has been shown to interfere with primary transcription of vesicular stomatitis virus (VSV) in tissue culture cells. As phosphorylation of the VSV P protein has been linked to its ability to stimulate viral transcription, we analyzed the phosphorylation status of this protein in human brain cells (U-87) stably transfected with MxA. We observed a general increase in cellular kinase activity in the presence of MxA, affecting both cellular proteins and VSV P protein. Phosphorylation of the latter was up to threefold higher both in vivo and in vitro. In vitro phosphorylation of recombinant VSV P protein could be enhanced in MxA-negative cell extracts after exogenous addition of recombinant His-MxA. Biochemical evidence and phosphorylation of a mutant P protein lacking the recognized casein kinase II (CKII) sites suggested that hyperphosphorylation of VSV P protein was not due to a stimulation of CKII. We thus propose that expression of MxA in human brain cells is associated with the stimulation of a cellular kinase that is active in phosphorylating both cellular target proteins and VSV P protein.

Expression of a renal type I sodium/phosphate transporter (NaPi-1) induces a conductance in Xenopus oocytes permeable for organic and inorganic anions

Two distinct molecular types (I and II) of renal proximal tubular brush border Na+/Pi cotransporters have been identified by expression cloning on the basis of their capacity to induce Na+-dependent Pi influx in tracer experiments. Whereas the type II transporters (e.g., NaPi-2 and NaPi-3) resemble well known characteristics of brush border Na+/Pi cotransport, little is known about the properties of the type I transporter (NaPi-1). In contrast to type II, type I transporters produced electrogenic transport only at high extracellular Pi concentrations (> or =3 mM). On the other hand, expression of NaPi-1 induced a Cl- conductance in Xenopus laevis oocytes, which was inhibited by Cl- channel blockers [5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) > niflumic acid >> 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid]. Further, the Cl- conductance was inhibited by the organic anions phenol red, benzylpenicillin (penicillin G), and probenecid. These organic anions induced outwardly directed currents in the absence of Cl-. In tracer studies, we observed uptake of benzylpenicillin with a Km of 0.22 mM; benzylpenicillin uptake was inhibited by NPPB and niflumic acid. These findings suggest that the type I Na+/Pi cotransporter functions also as a novel type of anion channel permeable not only for Cl- but also for organic anions. Such an apical anion channel could serve an important role in the transport of Cl- and the excretion of anionic xenobiotics.

The IVS6 segment of the L-type calcium channel is critical for the action of dihydropyridines and phenylalkylamines

The current through the L-type calcium channel is inhibited and stimulated by distinct dihydropyridines at very low concentrations. The molecular determinants for the high affinity block and stimulation were investigated using chimeras between the class C and E calcium channels. Mutation of three amino acids in the last putative transmembrane segment (IVS6) of the alpha1C subunit decreased the affinity for (+)isradipine 100-fold without significantly affecting the basic properties of the expressed channel. Mutation of two of these three amino acids completely abolished the stimulatory effect of the calcium channel agonist Bay K 8644. These mutations only slightly affected the blocking efficacy of mibefradil and the phenylalkylamine devapamil. Three distinct but adjacently located amino acids mediated the high affinity block by devapamil. These results suggest that the IVS6 segment of the alpha1C subunit is critical for the high affinity interaction between the L-type calcium channel and the calcium channel agonist Bay K 8644 and the two antagonists isradipine and devapamil.

Conversion to microemulsion cyclosporine in stable renal transplant patients: results after one year

We switched 302 renal transplant patients from the conventional to a new microemulsion formulation of cyclosporine, to study the latter's safety and efficacy. We used a simple 1:1 conversion of the patient's total daily dose. We measured trough drug levels as well as serum creatinine, liver enzymes, uric acid, and blood pressure values at baseline and at days 4, 8, 15, 29, and months 3, 6 and 12 after drug substitution. Dose adjustments directed at trough levels 80-120 ng/ml were performed, starting at day 8. Within the 12-month observation period, the cyclosporine dose was reduced by 14.7% (204 +/- 60 mg/day baseline vs 174 +/- 51 mg/day after conversion, p < or = 0.001). By day 8, the 1:1 dosage conversion resulted in a modest mean increase in drug trough levels (114 ng/ml baseline vs 120 ng/ml, p < or = 0.01). This increase was accompanied by an increase in serum creatinine concentration, a decrease in calculated creatinine clearance, and an increase in uric acid values (p < or = 0.05). Liver enzymes remained unchanged while systolic and mean arterial blood pressure decreased (p < or = 0.05). After one month, drug trough levels had decreased to baseline (112 ng/ml) and remained there until month 6. They were significantly lower after 12 months (102 +/- 33 ng/ml, p < or = 0.001). Plasma creatinine values decreased to below baseline by month 6 (p < or = 0.001) and month 12 (p < or = 0.001). Twenty-four (8%) biopsy proven rejection episodes and 7 cases of cyclosporine attributed nephrotoxicity occurred in these 302 patients within these 12 months. We conclude, that a 1:1 conversion from conventional to the microemulsion form of cyclosporine is efficacious and safe. However, we advise an initial 10% decrease in dose reduction in those patients whose trough levels are in the high-normal range.

High-performance liquid chromatographic-ultraviolet assay for the simultaneous quantitation of BMS-181101 and its putative hydroxy metabolites in rat and monkey plasma

A specific, accurate, precise, and reproducible High-performance liquid chromatographic-Ultraviolet (HPLC-UV) method was developed for the simultaneous quantitation of BMS-181101 (I), a new antidepressant, and its putative metabolites, 6'-hydroxy (II) and 7'-hydroxy (III) of BMS-181101 in rat and monkey plasma. The assay procedure involved solid-phase extraction of the three analytes and the internal standard (IS; BMY-42568) on 1 mL Bond Elut CN cartridge using an automated solid phase extraction controller (ASPEC) system. The final elution of the analytes was performed using 0.25% triethylamine in methanol. The eluate mixture was evaporated to dryness, the residue was reconstituted in the mobile phase and injected onto a Zorbax Phenyl column (4.6 x 250 mm; 5 microns) at a flow-rate of 1.2 mL/min. The mobile phase consisted of 20% acetonitrile, 10% methanol, 69% water and 1% 1.0 M ammonium phosphate and 1.0 M tetramethylammonium hydroxide mixture adjusted to pH 3 by phosphoric acid. An ultraviolet absorbance detector set at 287 nm was used to detect the analytes. The nominal retention times were 5, 8, 15, and 18 min for II, III, I, and IS, respectively. The standard curves for the three analytes were linear in the concentration range of 50-1000 ng/mL. The lower limit of quantitation was 50 ng/mL for each analyte. The analyses of quality control (QC) samples indicated that the nominal values could be predicted with an accuracy of (+/-) 10.5% for all three analytes in rat and monkey plasma. The precision values of the QC samples for all three analytes were within 12.7% RSD for rat and monkey plasma. All three analytes and the IS were stable in the autosampler for at least 38 h; freeze/thaw stability of the 3 analytes was established for three cycles. Stability of BMS-181101 was established for one month at -20 degrees C. The application of the assay to a pharmacokinetic study in monkey is described.

Clinical applications of registration and fusion of multimodality brain images from PET, SPECT, CT, and MRI

Several image registration and fusion techniques have been discussed in the context of applying them to patient studies obtained during clinical workup. Mainly retrospective techniques, either automated or interactive, seem to be flexible enough to be adapted to clinical situations. Examples are provided to express the usefulness of multi-modality, multi-tracer brain studies.

Substitution of conventional cyclosporin with a new microemulsion formulation in renal transplant patients: results after 1 year

BACKGROUND

A new galenic form of cyclosporin A has been developed, based on microemulsion technology. The bioavailability of the compound is relatively independent of food intake and bile flow. It was the purpose of this prospective clinical trial to study the safety of the microemulsion form of cyclosporin A.

METHODS

Three hundred and two renal transplant patients, stratified according to transplant age, were switched from the conventional to the new microemulsion formulation of cyclosporin A. A 1:1 conversion ration was used. Measurements included CsA levels, S-creatinine, liver enzymes, uric acid, and blood pressure. Measurements were performed at baseline and on days 4, 8, 15, 29 and months 3, 6 and 12 after conversion. Dose adjustments were performed to achieve through levels of 80-120 ng/ml.

RESULTS

Within the 12-month observation period the cyclosporin dose was reduced by 14.7% (from 204 +/- 60 mg/day at baseline to 174 +/- 51 mg/day after conversion, P < 0.001). Acutely, i.e. by day 8, 1:1 dose conversion resulted in a modest increase of mean drug through levels (from 114 ng/ml at baseline to 120 ng/ml, P < 0.01). This increase was accompanied by an increase in serum creatinine concentration, a decrease in calculated creatinine clearance, and an increase in uric acid values (P < or = 0.05). Liver enzymes remained unchanged while systolic and mean arterial blood pressure decrease (P < 0.05). After 1 month, drug through levels had decreased to baseline (112 ng/ml) and remained there until month 6. They were significantly lower after 12 months (102 +/- 33 ng/ml), P <0.001). Creatinine clearance values increased to above baseline at 6 and 12 months. Within the 1-year period there occurred 24 (= 8%) episodes of biopsy proven rejection and seven episodes of cyclosporin-attributed nephrotoxicity.

CONCLUSIONS

The 1:1 conversion from conventional cyclosporin A to the microemulsion formulation s efficacious and safe, but an initial dose reduction of 10% is advised in patients with through levels in the high-normal range.

Two stable cell lines for screening of calcium channel blockers

Stable cell lines are potentially excellent tools for large-scale screening of new compounds. Two carboxyterminal-deleted constructs of the two splice variants a and b of the calcium channel class C alpha 1 subunit were expressed stably in HEK 293 cells. Each cell line produced regular L-type calcium currents. The opening and closing of the calcium channel elicited by potassium depolarization was followed by Fura-2 transients. These transients were blocked by the calcium channel blocker mibefradil with a concentration for 50% inhibition of 1.7 microM. The cell lines expressing the truncated cardiac alpha 1C-a or smooth muscle alpha 1C-b calcium channel were both blocked by nisoldipine under patch clamp conditions. Nisoldipine interacted with higher affinity with the alpha 1C-b channel than with the alpha 1C-a channel. These results indicate that the two cell lines retain the differential dihydropyridine sensitivity of smooth muscle and cardiac calcium channels and may be potential tools for the screening of L-type calcium channel blockers.

Properties of electrogenic Pi transport by a human renal brush border Na+/Pi transporter

Inorganic phosphate (Pi) induced an inward current (IP) in Xenopus oocytes expressing the human renal Na+/Pi cotransporter NaPi-3. At 100mM Na+, Pi-transport was independent of the holding potential and resulted in an apparent Km of 0.08 mM; lowering the Na+ concentration to 50 mM resulted in an increase of the apparent Km to 0.22 mM at -50 mV and to 0.31 mM at -90 mV. In contrast, the apparent Km for Na+ was not significantly influenced by the holding potential. A decrease of the pH from 7.8 to 6.8 resulted in a decrease of IP at 50 mM Na+, but not at 150 mM Na+. Arsenate induced inward currents through NaPi-3 and decreased the apparent Km in measurements of IP. Phosphonoformic acid itself induced no currents, but inhibited Pi-induced currents with an apparent Ki of 3.6 mM. In summary, NaPi-3 displays characteristic Na+/Pi cotransporter properties with relevant interactions with arsenate (transport substrate) and phosphonoformic acid (inhibitor). Monovalent and divalent Pi both appear to be transported by NaPi-3.

Presurgical visualization of primary breast carcinoma with PET emission and transmission imaging

The aim of this study was to investigate a technique that visualizes findings from PET images in a context useful for surgery.

METHODS

Simultaneously acquired PET emission and transmission scans were used. By applying a multipurpose imaging, registration and rendering tool (MPM), displays of orthogonal and volume-rendered views or any combination thereof were obtained. The PET emission and transmission scans were acquired under routine conditions. The final user-customized display (with a combination of orthogonal cuts and rendered views) was processed in 10 min or less on commercially available hardware. Distinct features of the body shape were clearly visible on the volume-rendered transmission views. Hot spots, e.g., in primary breast cancer, from the emission scans could be easily assessed in their localization relative to the body outline.

CONCLUSION

Rendering of the main signatures in a single comprehensive display makes this method potentially valuable for simple presurgical workup and therapeutic management of breast cancer.

Heterogeneity of bromodeoxyuridine sensitivity of cultured cells from melanoma metastases

Continuously growing cell cultures, testing positive for tyrosine activity, were derived from two brain and three lymph-node metastases of five patients with malignant melanoma. These cell cultures were analyzed regarding their proliferation rate with continuous bromodeoxyuridine (BrdUrd) labeling followed by bivariate Hoechst 33258/ethidium bromide flow cytometry. Melanoma cell cultures are more sensitive toward BrdUrd in comparison to human diploid fibroblast cultures: 50% growth inhibition at 360 +/- 130 microM BrdUrd (range: 130-520; n = 11) vs. 650 +/- 50 microM BrdUrd (n = 3) for fibroblasts. Moreover, BrdUrd sensitivity in melanoma cells is oxygen dependent: 50% growth inhibition at 200 +/- 55 microM (range: 65-400 microM) for 20% oxygen vs. 360 +/- 130 microM BrdUrd for 5% oxygen. The cell cycle kinetic mechanisms of BrdUrd-induced growth inhibition is accumulation of cells in the G2 phase. Cultures from a single metastasis showed up to a 3-fold variation in BrdUrd sensitivity. In one of the brain metastases two populations of different ploidy level (pseudotriploid vs. pseudotetraploid) and BrdUrd sensitivity could be resolved. Thus, continuous BrdUrd labeling followed by bivariate Hoechst 33258/ethidium bromide flow cytometry is a powerful tool to detect heterogeneity in proliferative capacity and drug sensitivity of cell populations within one tumor biopsy.

Involvement of cellular casein kinase II in the phosphorylation of measles virus P protein: identification of phosphorylation sites

The phosphoprotein P gene of measles virus (Edmonston strain) has been cloned in the Escherichia coli expression vector pET-3a with a histidine tag at the C-terminal end. The expressed protein was soluble, unphosphorylated, and constituted 10 to 20% of total cellular protein. Recombinant P protein purified by Ni-affinity chromatography was found to be efficiently phosphorylated in vitro by recombinant casein kinase II (CKII) or by the CKII activity present in the uninfected cell extract. A comparison of phosphopeptide analyses between the in vivo- and the in vitro-32P-labeled P proteins revealed that both proteins share common phosphorylation sites. In an attempt to identify the exact site of the CKII-mediated phosphorylation, we altered specific serine residues located within the CKII consensus motif to alanine by site-directed mutagenesis. The results indicate that Ser 86, Ser 151, and Ser 180 located within the N-terminal half of the P protein are involved in the CKII-mediated phosphorylation of the P protein.

On the regulation of the expressed L-type calcium channel by cAMP-dependent phosphorylation

The Ca2+ channel subunits alpha 1C-a and alpha 1C-b were stably expressed in Chinese hamster ovary (CHO) and human embryonic kidney (HEK) 293 cells. The peak Ba2+ current (IBa) of these cells was not affected significantly by internal dialysis with 0.1 mM cAMP-dependent protein kinase inhibitor peptide (mPKI), 25 microM cAMP-dependent protein kinase catalytic subunit (PKA), or a combination of 25 microM PKA and 1 microM okadaic acid. The activity of the alpha 1C-b channel subunit expressed stably in HEK 293 cells was depressed by 1 microM H 89 and was not increased by superfusion with 5 microM forskolin plus 20 microM isobutyl-methylxanthine (IBMX). The alpha 1C-a.beta 2.alpha 2/delta complex was transiently expressed in HEK 293 cells; it was inhibited by internal dialysis of the cells with 1 microM H 89, but was not affected by internal dialysis with mPKI, PKA or microcystin. Internal dialysis of cells expressing the alpha 1C-a.beta 2.alpha 2/delta channel with 10 microM PKA did not induce facilitation after a 150-ms prepulse to +50 mV. The Ca2+ current (ICa) of cardiac myocytes increased threefold during internal dialysis with 5 microM PKA or 25 microM microcystin and during external superfusion with 0.1 microM isoproterenol or 5 microM forskolin plus 50 microM IBMX. These results indicate that the L-type Ca2+ channel expressed is not modulated by cAMP-dependent phosphorylation to the same extent as in native cardiac myocytes.

Heavy metal mediated inhibition of rBAT-induced amino acid transport

rBAT, a protein which is located in the brush border membranes of intestine and renal proximal tubule cells, was recently shown to induce electrogenic countertransport of neutral and dibasic amino acids after its expression in Xenopus oocytes. Here, we studied the effects of heavy metals on rBAT induced amino acid transport in Xenopus oocytes to clarify a possible involvement of rBAT in heavy metal-induced aminoaciduria. The heavy metals Hg2+ and Pb2+ inhibited rBAT-induced amino acid transport with a different profile of action. The Pb2+ mediated inhibition occurred rapidly upon superfusion and was readily reversible upon washout. The maximal inhibition caused by Pb2+ was about 50% of the amino acid-induced currents at an apparent affinity (Km) of about 10 microM. In contrast, the Hg(2+)-mediated inhibition occurred rather slowly, depending on its concentration, and was not reversible during washout with control solution. However, the Hg(2+)-mediated amino acid transport inhibition could be reversed with Hg2+ chelating agents and reducing compounds. Other oxidative agents, such as the membrane permeable 2,2'-Dithio-bis(5-Nitropyridine) (DTNP), but not the membrane impermeable 5,5'-Dithio-bis (2-Nitrobenzoic acid) (DTNB), mimicked the effect of Hg2+, and their effect could similarly be reversed with 2,3-Dihydroxybutane-1,4-dithiol (DTE). In conclusion, Pb2+ and Hg2+ inhibit rBAT-induced amino acid transport in a noncompetitive, allosteric fashion. Blockade of rBAT-induced amino acid transport may be involved in aminoaciduria following mercury or lead intoxication.

Alpha 1-proteinase inhibitor abrogates proteolytic and secretagogue activity of cystic fibrosis sputum

Airway disease in cystic fibrosis (CF) is characterized by neutrophil-dominated chronic inflammation with an excess of uninhibited neutrophil elastase (NE), which is regarded as an important factor in progressive lung destruction. Therefore, inhalation of alpha 1-proteinase inhibitor (alpha 1-PI) seems to be a reasonable therapeutic approach. To estimate its therapeutic potential, we quantitatively investigated the in vitro interactions of exogenous alpha 1-PI with CF sputum samples (n = 28). High NE and alpha 1-PI concentrations were detected in CF sputum (6.03 +/- 0.78 and 2.56 +/- 0.16 mumol/l, respectively). There was significant NE activity (2.6 +/- 0.4 U/l) due to both the surplus of NE and proteolytic degradation of alpha 1-PI. Addition of exogenous alpha 1-PI resulted in a dose-dependent inhibition of NE activity in CF sputum; > 90% inhibition was achieved at 10 micrograms/ml alpha 1-PI. Purified NE as well as CF sputum potently induced secretion from porcine tracheal glands. Corresponding to inhibition of NE activity, CF sputum-induced secretion was also inhibited by exogenous alpha 1-PI; > 90% inhibition was also achieved at 10 micrograms/ml alpha 1-PI. Incubation of exogenous alpha 1-PI with CF sputum for 24 h did not reduce the inhibitory effects. From our in vitro results we conclude that inhalation of alpha 1-PI might effectively inhibit both NE activity and airway gland hypersecretion in CF airways.

Cytokines in neutrophil-dominated airway inflammation in patients with cystic fibrosis

Bronchopulmonary disease in patients with cystic fibrosis (CF) is a paradigm of neutrophil-dominated airway inflammation. We hypothesized that proinflammatory cytokines contribute to a localized neutrophil-dominated inflammatory state as present in CF airways. In a cross-sectional study, we analyzed 63 sputum samples from 33 CF patients for concentrations of the cytokines interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-8, tumor necrosis factor-alpha (TNF-alpha), and granulocyte-colony stimulating factor (G-CSF) by means of enzyme-linked immunosorbent assay. Furthermore, the activity of neutrophil elastase (NE) in the sputum samples was determined using a specific chromogenic substrate. Compared to sputum samples from 10 healthy controls, there were significantly increased concentrations of IL-1 beta, IL-8 and TNF-alpha in the CF sputum samples. The concentration of IL-8 correlated significantly with NE activity in the CF sputum samples. In CF patients with airways chronically colonized with Pseudomonas aeruginosa, IL-8 concentrations in sputum were significantly enhanced. In glucocorticoid-treated patients, IL-1 alpha and G-CSF sputum concentrations were significantly lower when compared to levels in the other patients. These results show that there are high concentrations of proinflammatory cytokines in CF airways which may contribute to the localized neutrophil-dominated inflammatory state found clinically.

Cystic fibrosis sputum induces a secretory response from airway gland serous cells that can be prevented by neutrophil protease inhibitors

High activities of the neutrophil proteases, elastase and cathepsin G, are found in the sputum of patients with cystic fibrosis (CF). Because both proteases have been shown to be potent secretagogues for airway submucosal glands, and because hypersecretion is a characteristic feature of CF, the objective of the present study was to examine whether there is secretagogue activity in CF sputum, and to determine the contribution of neutrophil proteases to the secretagogue activity. Confluent monolayers of cultured bovine tracheal serous cells were pulse-labelled with Na2(35)SO4, incubated with diluted CF sputum supernatants in the presence or absence of different protease inhibitors, and the subsequent release of the radio-labelled macromolecules was measured. CF sputum potently induced secretion concentration-dependently. Addition of the selective neutrophil elastase inhibitor ICI 200,355 inhibited the secretory response to CF sputum supernatant by 89%. Addition of a cathepsin G-inhibitor resulted in further inhibition of the secretory response. Addition of phosphoramidon, a drug known to inhibit Pseudomonas aeruginosa elastase, had no effect. We conclude that CF sputum potently stimulates airway submucosal gland cell secretion. These studies with protease inhibitors suggest that neutrophil proteases account substantially for the secretagogue activity present in CF sputum.