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Biomedical subjects

Frank Schmidt

Publications and source records attributed to Frank Schmidt.

26 records · Page 2Linked to original sources
PubMed2003

Iterative data analysis is the key for exhaustive analysis of peptide mass fingerprints from proteins separated by two-dimensional electrophoresis.

Peptide mass fingerprinting (PMF) is a powerful tool for identification of proteins separated by two-dimensional electrophoresis (2-DE). With the increase in sensitivity of peptide mass determination it becomes obvious that even spots looking well separated on a 2-DE gel may consist of several proteins. As a result the number of mass peaks in PMFs increased dramatically leaving many unassigned after a first database search. A number of these are caused by experiment-specific contaminants or by neighbor spots, as well as by additional proteins or post-translational modifications. To understand the complete protein composition of a spot we suggest an iterative procedure based on large numbers of PMFs, exemplified by PMFs of 480 Helicobacter pylori protein spots. Three key iterations were applied: (1) Elimination of contaminant mass peaks determined by MS-Screener (a software developed for this purpose) followed by reanalysis; (2) neighbor spot mass peak determination by cluster analysis, elimination from the peak list and repeated search; (3) re-evaluation of contaminant peaks. The quality of the identification was improved and spots previously unidentified were assigned to proteins. Eight additional spots were identified with this procedure, increasing the total number of identified spots to 455.

Cluster Analysis↗
PubMed2003

Comparative urodynamic patterns of bladder pressure, contractility and urine flow in man and rat during micturition.

A urodynamic characterization of the distinctive patterns of normal micturition in man and rat was undertaken. Data were obtained from experimental studies where bladder pressure was measured suprapubically obviating urethral instrumentation. Ambulatory urodynamic studies were conducted with 17 asymptomatic male volunteers. Bladder pressure was monitored via a supra-pubic catheter and abdominal pressure via a rectal balloon using a UPS2020 ambulatory system. Average duration of each monitoring period was 20.5 hours. Detrusor pressure and flow rate records from each subject were identified and consecutive filling and voiding phases were averaged over the entire monitoring period using the onset of micturition as a time marker. The averaged pattern of pressure, flowrate, cumulative volume, and contractility curves for each subject as well each for group was computed and graphically presented. For comparison, the micturition phase of 18 anesthetized rats were used. A continuous CMG was performed and bladder pressure was recorded suprapubically. For each group the averaged parameters of urethral opening pressure, Max Detrusor pressure, Detrusor pressure at Max flowrate, bladder capacity, and WF were extracted and compared statistically. Numerical values are M +/- SE. The urodynamic temporal patterns observed during the micturition phase of the CMG in terms of detrusor pressure and associated flow, in both man and rat posses striking qualitative similarities. These are particularly striking during the onset of micturition in the great majority of animals. Furthermore the pressures generated by the bladder before and during micturition are quantitatively similar. However there were also distinct differences particularly in the pattern observed during voiding when bladder pressure was oscillatory. The temporal sequence of detrusor pressure and flow in man and rat contains many qualitative and quantitative similarities rendering the rat's potential as a particularly useful model in the study of the onset of micturition.

Animals↗
PubMed2002

Generation of minimal protein identifiers of proteins from two-dimensional gels and recombinant proteins.

We describe the technical feasibility and methodology to characterize a protein by a minimal set of structural information generated by matrix assisted laser desorption/ionization (MALDI)-mass spectrometry, termed a "minimal protein Identifier" (MPI). MPIs can be determined for proteins from two-dimensional gels and recombinant proteins and can be used to compare and identify proteins from these sources.

Brain↗
PubMed2002

MR-guided percutaneous core biopsy of small breast lesions: first experience with a vertically open 0.5T scanner.

PURPOSE: The growing use of highly sensitive but only moderate specific breast MRI requires the development of both minimal-invasive as well as precise biopsy systems. The aim of the study was to prove the accuracy and feasibility of a biopsy procedure carried out in prone position in a vertically opened MR imager. MATERIALS AND METHODS: The biopsies were carried out in 21 women with lesions visible on MRI alone using an open breast coil with an integrated biopsy device. A 14 G coaxial needle was placed under near real-time MRI-guidance. After the tip of this needle was verified in contact with the lesion, we used a non MR-compatible, but MR-safe biopsy gun with a 16 G canula to take four to eight cores. RESULTS: We found eight malignant and 12 benign lesions. In one patient the procedure was not successful. In case of malignancy, the operation confirmed the diagnosis in all cases. The 12/21 patients with benign lesions have been followed without evidence of lesions growth over eight to 28 months. CONCLUSION: The described procedure allows MRI-guided minimal invasive core biopsy of small breast lesions (five to 17 mm) with a high degree of accuracy.

Adult↗
PubMed2002

Urodynamic patterns of normal male micturition: influence of water consumption on urine production and detrusor function.

PURPOSE: Urodynamic characterization of normal male micturition can be a useful standard in the analysis of data on patients complaining of voiding dysfunction. The validity of such a standard is based on the need to obtain baseline parameters of pressure flow values, an important consideration when evaluating prostatic obstruction and its treatment. While current numerical pressure flow values provide a useful summary of the voiding sequence, a more complete analysis of the pattern of normal voiding may reveal more functionally useful information concerning micturition. We establish basic experimental conditions that simulate normal voiding of physiologically produced urine by the kidneys measured at intervals representing real stages of bladder filling. We report the results of an investigation designed to study consecutive micturitions at bladder volumes determined by water consumption and endogenous circadian rhythm. Our particular focus is to examine critically the urodynamic pattern of pressure flow and obtain evidence to support the hypothesis that fluid consumption has an important role in detrusor function. MATERIALS AND METHODS: Urodynamic studies were conducted on 39 asymptomatic male volunteers with a mean age of 25.8 years (range 21 to 31) and mean weight of 75.5 kg. (range 63 to 95). Volunteers were divided into 2 groups according to water consumption regimen of 30 ml./kg. daily (17 patients, group 1) and 60 ml./kg. daily (12, group 2). Bladder pressure was monitored via a suprapubic catheter and abdominal pressure was measured via a rectal balloon using an ambulatory system. Average duration of each monitoring period was 20.5 hours. Detrusor pressure and flow rate records from each subject were identified, and consecutive filling and voiding phases were averaged during the entire monitoring period using the onset of micturition as a time marker. The average pattern of pressure, flow rate, cumulative volume and contractility curves for each subject, as well each for group, was computed and graphically presented. For each group the average parameters of urethral opening pressure, maximum detrusor pressure, detrusor pressure at maximum flow rate, bladder capacity and bladder contraction strength were calculated and compared statistically. Numerical values are mean +/- SE. RESULTS: Water consumption and urine production rate influenced the pattern and many of the urodynamic parameters of micturition. In both groups there was a detrusor pressure increase before voiding and numerically maximum detrusor pressure consistently occurred before micturition started. Micturition pattern showed an asymptotic relationship between pressure and flow. Doubling of water consumption increased urethral opening pressure from 51.2 +/- 3.2 to 61.5 +/- 5.1 (p <0.05), maximum detrusor pressure from 58.9 +/- 4.5 to 70.0 +/- 6.2 cm. H(2)O (p <0.01) and contractility from 15.4 +/- 1.4 to 17.7 +/- 1.4 w/m(2). There were no significant differences due to water consumption in maximum flow rate (24.4 +/- 1.4 to 25.2 +/- 1.8 ml. per second) or bladder capacity (286 +/- 20 to 329 +/- 15 ml.) but a significant increase in the number of micturitions from 5.8 +/- 0.5 to 9.8 +/- 0.5 per day (p <0.001) proportional to water consumption. CONCLUSIONS: The configuration of the observed pressure flow characteristics of the normal male is suggestive of the "Starlings law" relationship and the pattern of the urodynamic parameters were markedly different from those reported in the current standardization literature, suggesting the need to revise the current concept of normal male micturition. Voiding pressure and contractility increased in accordance with water consumption and urine production.

Adult↗
PubMedDate not supplied

Management and outcome in patients with Klatskin-mimicking lesions of the biliary tree.

The preoperative and even intraoperative differentiation between benign and malignant strictures at the hepatic hilum remains difficult. The aim of this study was to assess clinical, radiologic, intraoperative, and histopathologic findings; surgical treatment; and outcome of patients with Klatskin mimicking benign lesions. Of 49 consecutive patients who were operated on the initial preoperative radiologic diagnosis of hilar adenocarcinoma (Klatskin tumor), 7 (14%) had benign conditions after final histopathologic diagnosis. Pretreatment work-up, therapy, and outcome of these patients were analyzed. Based on preoperative clinical symptoms, imaging assessment, and CA19-9 values, all seven patients were classified as having malignant neoplasms. At laparotomy, the tumors of six patients were judged to be malignant. Five patients underwent hilar resection and concomitant liver resection, and two patients underwent hilar resection alone. There were no operative deaths. The definitive histopathologic examination showed severe cholangitis with extensive periductal fibrosis in all patients. After a median follow-up of 32 months, all patients are well. Clinical presentation and imaging assessment were similar for Klatskin tumors and benign fibrosing disease; therefore, an aggressive resectional approach is justified in any patient with suspicious obstruction of the liver hilum.

Adult↗
PubMedDate not supplied

Proteus syndrome.

Proteus syndrome is a rarely described dysplasia syndrome of the group of congenital hamartomas that arises from mosaic mutation. An extraordinary case history including imaging studies will be reported. This 17-year-old girl suffered from cachexia, lifelong chronic obstipation, different dysplasias, and lipomatous tumor-like lesions. The following findings were marked: macrodactyly, nevi, hemihypertrophy, aggressive lipomatosis, hemangiomas of the spleen, and skull and cerebral malformations. Additionally, an intestinal affection with fatty wall thickening was detected. In contrast to reports in the literature describing a reduced lifespan with a mean of few years, our patient is still alive. The treatment should take a palliative symptomatic approach considering the clinical situation.

Adipose Tissue↗