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J Preisler

Publications and source records attributed to J Preisler.

At least 19 recordsLinked to original sources
PubMed2006

High-throughput axial MALDI-TOF MS using a 2-kHz repetition rate laser.

A high-throughput axial MALDI-TOF mass spectrometer utilizing a laser with a 2-kHz pulse repetition-rate was constructed and tested. This fast mass spectrometer provided a data acquisition rate 10 times faster than a commercially available (200 Hz) axial mass spectrometer, while maintaining comparable limits of detection (200 amol of Glu fib peptide). Mass resolution, only slightly less than the commercial instrument (10 000 vs 14 000), was sufficient for baseline resolution of isotopic clusters of peptides with m/z <2700. A new method of mass calibration, which combined a limited number of internal and external standards, provided the same 15 ppm mass accuracy over the entire sample plate on either instrument. Implementing the 2-kHz laser required a faster data acquisition system and high-voltage pulse electronics, together with a novel strategy for rapid sample plate movements during acquisition, to achieve a sample analysis rate of up to 2 spots/s (with 800 shots/spot). The overall performance of the fast MALDI-TOF MS instrument was demonstrated by the acquisition, in 12 min, of an LC-MS data set from a plate of 625 fractions collected during LC separation of an 16O/18O differentially labeled proteomic sample of a tryptic digest of an E. coli lysate.

Bacterial Proteins↗
PubMed2000

Capillary electrophoresis--matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using a vacuum deposition interface.

An improved vacuum deposition interface for coupling capillary electrophoresis with MALDI-TOF MS has been developed. Liquid samples consisting of analyte and matrix were deposited on a moving tape in the evacuated source chamber of a TOF mass spectrometer, enabling 24 h of uninterrupted analysis. The vacuum deposition procedure was compared with the dried-droplet method, and it was found that vacuum deposition generated significantly more reproducible signal intensity, eliminating the need for "sweet spot" searching. A concentration detection limit in the low-nanomolar range has been achieved with a low-attomole amount of sample consumed per spectrum. In addition, ion suppression caused by hydrophobicity differences in the analytes was reduced. To minimize ion suppression further, separation prior to MALDI MS analysis was employed. The performance of capillary electrophoresis (CE)-MALDI-TOF MS using the vacuum deposition interface was evaluated with a peptide mixture injected at low-femtomole levels. All peptides were baseline resolved with separation efficiencies in the range of 250000-400000 plates/m (2-3-s band half-width), demonstrating the high separation efficiency of the CE-MALDI MS coupling. A fast (approximately 40 s) CE separation of a mixture of angiotensins was found to reduce significantly ion suppression and enable trace level detection. It was also shown, for the analysis of an enolase digest, that sequence coverage of 65% was obtained using CE separation compared to 52% using step-elution solid-phase extraction and 44% in the control experiment using an unseparated mixture.

Electrophoresis, Capillary↗
PubMed1998

On-line MALDI-TOF MS using a continuous vacuum deposition interface.

In this work, a new interface for continuous on-line MALDI-TOF MS is presented. The sample, mixed with a suitable matrix, was transported into the evacuated source chamber of the mass spectrometer at liquid flow rates of 100-400 nL/min. The liquid sample matrix was deposited on a rotating quartz wheel and transported to the repeller, where laser desorption took place. Rapid evaporation of the solvent (water or methanol) on the surface of the wheel resulted in formation of a thin, approximately 50-micron-wide, sample trace. Scanning electron microscopic photographs of the vacuum-dried trace revealed the deposited material to consist of an amorphous film. Furthermore, sample uniformity along the trace, in conjunction with its narrow width, resulted in excellent signal reproducibility, with detection limits in the attomole range. The interface permitted the on-line coupling of microcolumn separation techniques with MALDI MS, as demonstrated in the capillary electrophoresis MALDI-TOF MS analysis of a 12-peptide mixture. The approach offers the potential for rapid separation and trace analysis of complex mixtures.

Spectrometry, Mass, Matrix-Assisted Laser Desorpti↗
PubMed1997

Laser photodissociation of insulin ions generated by matrix-assisted laser desorption.

A novel method for studying the ionization step of matrix-assisted laser desorption/ionization (MALDI) is demonstrated. A 193-nm pulse from an ArF excimer laser is used to photodissociate a portion of a plume of insulin ions generated by MALDI. Laser photodissociation (LPD) creates a "hole", i.e., a negative spike in the insulin peak in the time-of-flight (TOF) mass spectrum. The position of the hole in the mass spectrum provides useful measurements of the characteristics (position, time, and velocity) of insulin ions shortly after their creation. Although the performance of the method can be further improved, the data obtained could be used to refine our current understanding of MALDI and to improve the resolution of MALDI-TOFMS.

Insulin↗
PubMed1992

Screening of pulmonary hypertension in chronic obstructive pulmonary disease and silicosis by discriminant functions.

The aim of our prospective multicentric study was to develop a screening method for pulmonary hypertension in patients with chronic lung diseases. We investigated 710 patients in 10 hospitals: 315 males and 109 females with chronic obstructive pulmonary disease, and 286 males with silicosis. Manifest pulmonary hypertension was defined as pulmonary artery pressure greater than 20 mmHg (2.7 kPa) at rest. The multivariate statistical method used was a stepwise discriminant analysis. In males with chronic obstructive pulmonary disease, the diameter of the right descending pulmonary artery, forced expiratory volume in one second (FEV1) arterial oxygen tension (PaO2) at rest, and age turned out to be relevant for discrimination of groups with and without manifest pulmonary hypertension. For females the FEV1/FVC (forced vital capacity) ratio replaced the absolute value of FEV1 in the calculated discriminant function. In females, sensitivity and specificity were below 80%. In males, both were distinctly above 80%. In silicosis, the diameter of the right descending pulmonary artery was much less important, since it could frequently not be measured precisely. In these cases, precision of the prediction of about 80% could only be obtained by combined evaluation of spirometry, PaO2 during exercise, and body plethysmography. The calculated discriminant functions are appropriate for screening patients with risk of pulmonary hypertension. For different chronic lung diseases, and for both sexes, different combinations of parameters are relevant. The method is recommended to select patients who should undergo an invasive examination of pulmonary haemodynamics.

Discriminant Analysis↗
PubMed1989

[Spontaneous pneumothorax in chronic obstructive lung disease].

In the present study the aims were to analyse the difference in various treatment, complications and recurrence rates between patients with spontaneous pneumothorax and those associated with chronic obstructive lung disease (COLD). We made a retrospective analysis with regard to the therapy of all patients with spontaneous pneumothorax who were treated in the district lung hospital Lostau from 1. Jan 1986 to 31. Dec 1988 (171 patients, men: 136, women: 35). 45 patients suffered from a COLD (men: 42, women: 3). 3 methods of the treatment were set in: 1. conservative management by expectant observation, 2. the aspiration once or repeatedly with the pneumothorax apparatus and 3. the rubber-tube drainage. We consider the aspiration of spontaneous pneumothorax with pneumothorax apparatus as an effective method, which is not very burdensome for the patients. It is our opinion that the practice in patients with a COLD is more active than this in other patients, in form of the rubber-tube drainage.

Adult↗
PubMed1988

[Internal medicine treatment of pleural empyema].

We made a retrospective analysis with regard to the bacteriology and to the therapy of all patients with pleural empyema who were treated in the district lung hospital from 1. 1. 1982-31. 12. 1986. 92 patients had a non-specific empyema, only 3 patients had a specific empyema. All patients were aspirated repeatedly with physiological saline solution instillation and antimicrobic drug instillation in the pleural cavity. This daily aspiration and lavage was successfully in 65 patients. This method was ineffective in 30 patients. We treated 7 patients of this group by the closed drainage (rubber-tube drain), in 4 patients successfully. 3 patients had to be treated by a surgical operation. An insufficient obliteration of the cavity of empyema occurred also in 23 patients of this group. A systematic daily aspiration for a longer time led to regression of the cavity in 4 cases, whereas a surgical operation was necessary in 19 patients. We consider the daily aspiration and lavage as an effective method in patients in early acute stages of empyema.

Bacterial Infections↗
PubMed1987

[Treatment of spontaneous pneumothorax from the pulmonary internal medicine viewpoint].

We made a retrospective analysis with regard to the therapy of all patients with spontaneous pneumothorax who were treated in the district lung hospital Lostau from 1. 1. 1983 to 30. 6. 1985. We waited for the spontaneous regression at 10 patients with a partial pneumothorax, the relapse rate was 30% in these cases. Sixty three patients were aspirated once or repeatedly with the pneumothorax apparatus. Our own success rate was 78% with this therapy, the relapse rate 26%. We treated 18 patients by rubber-tube drain. It was successful in 94%, the relapse rate was 19%. A thoracoscopy with pleurodesis was necessary in one patient who was generally inoperable. Five patients were treated primarily surgically. The same therapy was carried out in 6 patients with bullous emphysema in the free period. We consider the aspiration of spontaneous pneumothorax with pneumothorax apparatus as an effective method, which is not very burden some for the patients. The continuous suction drainage was very important too in the differential therapy of our patients.

Adolescent↗
PubMed1986

[Asbestos carcinogenesis from clinical and hypothetical viewpoints].

On the basis of a case of mesothelioma of the pleura in a 28-year-old female who among our patients had the longest survival time after establishment of the diagnosis (31 months) the authors adopt a definite attitude to the problems of asbestosis. It can be regarded as ascertained that after asbest exposition a systemic contamination of the organism occurs. Apart from the inhalative intake further possibilities of the asbest fibre incorporation and the elimination are referred to. As to the cancerogenesis of asbest-induced malignomas the existing theories appear at present still insufficient; analogies to Virchow's irritation theory are possible in the serosa tumours.

Adult↗
PubMed1986

[Diagnosis of tuberculous pleurisy with special reference to thoracoscopic biopsy findings].

132 tuberculous pleurisies were diagnosed between 578 thoracoscopies from 1970 to June 1985. A histological confirmation of diagnosis was achieved in 51.5% of the specific pleurisies, whereas in 15.2% typical endoscopic findings were present. 33.3% of the diseases were diagnosed based on the clinical and roentgenological appearance or ex juvantibus after antituberculous therapy. An increase of histologically negative biopsies was noted after a pretreatment of more than 4 weeks before thoracoscopy. This fact is interpreted as caused by an increasing exudation of fibrin, which permits to perform a probe-excision only without optical control. If there were macroscopic findings suspicious for pleural tuberculosis a histological confirmation succeeded in 68.8%. In cases with the uncharacteristic picture of "fibrinous pleurisies" the diagnosis of tuberculosis was confirmed morphologically in 33.9%. These investigations support the diagnostic value of the macroscopic criteria in case of pleural tuberculosis which are reported by Sattler.

Biopsy↗
PubMed1986

[Aspergillus pneumonia].

Aspergilluspneumonia means a form of pulmonary aspergillus infection invading tissue and accidentally vessels of the lung. Because of lacking of typical clinical and roentgenological signs diagnose finding is realized by evidence of fungi (histology, culture, serology). From 87 aspergilloses 60 could staged as aspergillomas by the x-ray pictures. 27 cases were bronchiectases, carcinomas, bacterial pneumonias with aspergillus or pneumonias without other lung disorders and agents other than aspergillus. The difficulty to ensure the "pure" aspergilluspneumonia (invasive type) is pointed out, when histological proof is lacking. The therapeutical possibilities are discussed.

Aged↗
PubMed1985

[Indications for diagnostic thoracoscopy, based on biopsy results of 400 studies].

It is reported on the results of 401 thoracoscopies. The main indication for thoracoscopic examination was the differential diagnosis of pleural effusions (262 cases = 65.3%). A morphological confirmation was achieved in 88.0% of all malignant and in 43.0% of tuberculous pleural and lung diseases. A histopathological diagnosis was also found in 94.3% of diffuse lung diseases. For diagnosis of non-specific pleurisy it is necessary to exclude all other etiologic factors. Lympho-plasmacellular infiltrates were found in all cases of non-specific pleurisies. Thoracoscopic biopsy is also of great importance for accurate diagnosis of rheumatic pleuro-pulmonary manifestations. All other clinical methods are uncertain for rheumatic diseases affecting the pleura and lung. In cases of spontaneous pneumothorax it is possible to get valuable additional informations by thoracoscopic investigation. Indications of thoracoscopy are represented as a result of the review of literature and of the present material. Variations of thoracoscopy are discussed.

Biopsy↗
PubMed1984

[Lymphogranulomatosis and persistent left superior vena cava. Contribution to the diagnostic problem of the interference of morphologically different images].

Unilateral mediastinal dilatations are suspicious of the presence of a lymphogranulomatosis. It is reported on a case in which the diagnosis of Hodgkin's disease was rendered more difficult by a persistent left superior vena cava. The discussion of the case shows that in the differential-diagnostically problematic mediastinal region - corresponding to the clinical appearance - all methods available must be used for the clarification of the etiology.

Adult↗
PubMed1984

[Hemodynamics of microcirculation during thoracoscopy under anesthesia].

Under the conditions of the thoracoscopy under anaesthesia the behaviour of the haemodynamic measuring values is investigated in 10 patients of either sex. The time of intubation and the phase of the open thorax represent the most remarkable periods of examination which are parallel to the alterations of the arterial oxygen partial pressure and the pressure parameters of the circulations within the lesser an the systemic circulatory system. The investigation results obtained from the behaviour of the oxygen partial pressure will prove to be decisive, whether treatment with thorax opening under simultaneously carried out analytic blood-gas measurements should be recommendable.

Adult↗