A scientific relational database combined with a report generator for endoscopy in networks: EndoNet

BACKGROUND AND STUDY AIMS

The flexibility required in academic endoscopy units is not provided by the available database systems. In a project involving substantial cooperation between endoscopists and computer scientists, we have developed an adaptable database, combined with a report generator embedded in the hospital's intranet.

PATIENTS AND METHODS

Six workstations in different areas of the hospital were clustered with a UNIX operating system to implement multi-user capability and access control. A relational database was used to design an application appropriate to the specific needs of the endoscopy unit in a teaching hospital engaged in scientific research. Both the terminology used in standardized endoscopy nomenclature and a free text block facility were included. A graphical user interface was developed to assemble pertinent data, generate the reports, and supervise the database.

RESULTS

A total of 4936 examinations including 2988 patients were entered consecutively during continuous routine operation of the system. Complete report generation required five minutes (median; range 1-9 minutes). Both structured items and free text were used in all the reports. Querying of the database was possible, concerning matters such as the need for repeated endoscopic therapy in acute gastrointestinal bleeding (4%), the search for Helicobacter pylori in appropriate patients (64%), the rate of accidental pancreatic duct visualization in endoscopic retrograde cholangiography (24%), and links between examinations and active trials (2%). Indicating improved report quality, the number and the diameter of esophageal varices in patients with varices were more frequently reported with the new report system than with previous typed reports (P<0.001). An anonymous questionnaire revealed that the readability of the computer-generated reports was better than that of the previous typewritten reports (P=0.01).

CONCLUSIONS

This report describes the creation of a database application and a report generator meeting the needs of scientific and routine use, and the successful application of this system in an academic endoscopy unit.

[Airborne molds and their metabolites at workplaces in composting plants]

Airborne fungal contaminants in composting facilities gain more and more importance in regard to health hazards for workers and an emission of spores and microbial metabolites in the environment. Possible health impacts of bioaerosols are widely discussed from both an allergological and a toxicological point of view. The present study investigates in detail the exposure to airborne fungal spores at working places in compost plants. These fungal spores are compared to the spectrum of microbial volatile metabolites with regard to the physiological properties of each fungal species. The results indicate, that the spectrum of microbial volatile organic compounds (MVOC) as well as the production of mycotoxins can be specific for certain species. In addition to the pathogenic and allergological relevance, the fungi may have different toxicological health impacts. However, an evaluation of health effects caused by the great variety of volatile organic compounds remains difficult, since information on their toxicological impact is lacking.

Brain glucose metabolism with [18F]-fluorodeoxyglucose and positron emission tomography before and after surgical resection of epileptogenic cavernous angiomas

Surgery of cavernous angiomas is often proposed due to the epileptogenic and hemorrhagic potential of this lesion. Little information is available on the impact of surgical resection on brain metabolism, locally or at a distance from the lesion. Fifteen patients presenting with a cavernoma and epileptic seizures underwent positron emission tomography examinations before and 1 year after surgical resection. We studied the quantitative cerebral metabolic rate of glucose (CMRGlu) with [18F]-fluorodeoxyglucose. The global brain CMRGlu remained unchanged after surgery. There was a significant decrease of metabolism in the lesion hemisphere, which remained unchanged after surgery. The perilesional regions were less metabolic than the contralateral ones and less metabolic than remote regions within the same hemisphere, before and after surgery. The absence of pre- to postsurgical variations suggests that the metabolic consequences of the lesion are maintained despite the surgical procedure during long-term follow-up studies.

Mapping the stereospecificity of peptidyl prolyl cis/trans isomerases

The stereospecificity of peptidyl prolyl cis/trans isomerases (PPIases) was studied using tetrapeptide substrate analogs in which one amino acid residue was replaced by the cognate D-amino acid in various positions of the peptide chain. Reversed stereocenters around proline markedly increased the rate of the spontaneous trans to cis isomerization of the prolyl bond whereas cis to trans isomerizations were less sensitive. PPIases like human cyclophilin18, human FKBP12, Escherichia coli parvulin10 and the PPIase domain of E. coli trigger factor exhibited stereoselectivity demanding at the P1 to P2' position of the substrate chain. The discriminating factor for stereoselectivity was the lack of formation of the Michaelis complexes of the diastereomeric substrates. However, D-alanine at the P1 position preserved considerable affinity to the active site, and largely prevented activation of the catalytic machinery for all PPIases investigated.

Side-chain effects on peptidyl-prolyl cis/trans isomerisation

Peptidyl-prolyl cis/trans isomerisation has been frequently found as a rate limiting step in the folding of proteins. In order to determine whether the nature of the amino acid preceding proline controls the probability of cis prolyl bonds in native proteins, systematic studies on the thermodynamics and kinetics of the prolyl isomerisation in the pentapeptide series Ac-Ala-Xaa-Pro-Ala-Lys-NH2 were performed. All proteinogenic amino acids were substituted in the position preceding proline. When measured by 1H-NMR and CD spectroscopy both isomers proved to be devoid of ordered structure in the whole series of the oligopeptides in aqueous solution. Thus, isomerization rates and cis/trans ratios calculated from solvent jump and 1H-NMR magnetisation transfer experiments exclusively reflect the side-chain effects of the Xaa position in the peptide series. There is a rough correlation between the cis content in the oligopeptides and the propensity of Xaa-Pro cis prolyl bonds in proteins. This correlation suggests that the prolyl bond conformation is mainly determined by local effects in proteins. The rate constants kc-->t of pentapeptides containing unionised amino acids preceding proline range from 3.2 x 10(-3) s-1 (Xaa = Ala) to 0.5 x 10(-3) s-1 (Xaa = Trp) at 4 degrees C. Proline clustering led to an isomerisation cycle indicating considerable influence on the isomerisation rates of the peptide bond conformations flanking the rotating bond. Both tyrosine and histidine specifically reduce isomerisation rates severalfold by deprotonation of their respective side-chains.

Spinal cord ependymomas

Ependymomas are the most frequent spinal cord tumors in adult patients. Although magnetic resonance imaging can be a highly accurate diagnostic tool, it does not always provide accurate differentiation between ependymomas and astrocytomas. This is why the authors recommend surgical resection and histological evaluation in all intraspinal cord tumors. It cannot be said that a tumor is unresectable without first attempting to remove it. Complete removal should be accomplished whenever possible, and patients should undergo operation before they become neurologically impaired. Quality of life depends on preoperative neurological status. Postoperative radiotherapy should be avoided in all low-grade ependymomas even after partial removal. Radiotherapy may be used to treat anaplastic ependymomas, which are quite rare in the spinal cord. Patients with low-grade ependymomas must be followed for years and undergo reoperation if necessary. In our experience treating 93 spinal cord ependymomas, complete removal was achieved in 86 patients and only one patient underwent reoperation 18 years later for tumor recurrence. The gold standard in treatment protocol is gross-total resection without adjunctive radiation therapy. Good long-term outcomes have been achieved by using this strategy.

Experiences with novel techniques for reduction of stent flow in transjugular intrahepatic portosystemic shunts

The transjugular intrahepatic portosystemic shunt (TIPS) may deteriorate liver function and can cause encephalopathy in patients with cirrhosis of the liver. Then reduction of TIPS flow may be required. We here report several attempts to reduce shunt flow in TIPS-induced encephalopathy or liver function impairment with novel techniques. Three patients with cirrhosis of the liver were investigated: Two with severe recurrent encephalopathy and one with impaired liver function following TIPS insertion. Insertion of a reducing stent was ineffective to decrease shunt flow velocity in one patient with severe coagulopathy. Sufficient reduction of shunt flow was achieved by embolizing the space around the hourglass waist of the reducing stent with an occlusion emulsion. Insertion of a conventional stent within the preexisting TIPS with or without additional embolization reduced TIPS flow in the other patients. After reduction of shunt flow encephalopathy improved and liver function returned to the level before TIPS, respectively. During follow-up no occlusion of TIPS was observed. Thus, reduction of shunt flow velocity can be achieved by insertion of an additional stent into a curve-shaped TIPS. Embolization can be helpful to decrease TIPS flow, particularly in patients with severe coagulopathy. Reduction of TIPS flow can correct TIPS-induced complications.

Selective inactivation of parvulin-like peptidyl-prolyl cis/trans isomerases by juglone

In contrast to FK506 binding proteins and cyclophilins, the parvulin family of peptidyl-prolyl cis/trans isomerases (PPIases; E.C. 5.2.1.8) cannot be inhibited by either FK506 or cyclosporin A. We have found that juglone, 5-hydroxy-1,4-naphthoquinone, irreversibly inhibits the enzymatic activity of several parvulins, like the E. coli parvulin, the yeast Ess1/Ptf1, and human Pin1, in a specific manner, thus allowing selective inactivation of these enzymes in the presence of other PPIases. The mode of action was studied by analyzing the inactivation kinetics and the nature of products of the reaction of E. coli parvulin and its Cys69Ala variant with juglone. For all parvulins investigated, complete inactivation was obtained by a slow process that is characterized by pseudo-first-order rate constants in the range of 5.3 x 10(-)4 to 4. 5 x 10(-)3 s-1. The inactivated parvulin contains two juglone molecules that are covalently bound to the side chains of Cys41 and Cys69 because of a Michael addition of the thiol groups to juglone. Redox reactions did not contribute to the inactivation process. Because thiol group modification was shown to proceed 5-fold faster than the rate of enzyme inactivation, it was considered as a necessary but not sufficient condition for inactivation. When measured by far-UV circular dichroism (CD), the rate of structural alterations following thiol group modification parallels exactly the rate of inactivation. Thus, partial unfolding of the active site of the parvulins was thought to be the cause of the deterioration of PPIase activity.

Room-temperature vibrational difference spectrum for S2QB-/S1QB of photosystem II determined by time-resolved Fourier transform infrared spectroscopy

Time-resolved FTIR spectroscopy has been used to kinetically characterize the vibrational properties of intact photosystem II-enriched membrane samples undergoing the S1QB-to-S2QB- transition at room temperature. To optimize the experimental conditions for the FTIR measurements, oxygen polarographic and variable chlorophyll a fluorescence measurements were used to define the decay of S2 and QA-, respectively. The flash-induced S2QB-/S1QB difference spectra were measured at a temporal resolution of 4.44 s and a spectral resolution of 4 cm-1. An intense positive band is observed at 1480 cm-1 in the difference spectrum and shows a slow decay with a half time of approximately 13 s. Based on its decay kinetics and analogy to the infrared absorption of QA- of photosystem II and QB- in bacterial reaction centers, we conclude that the 1480 cm-1 band arises from QB- of PSII and tentatively assign it to the upsilon(CO) mode of the semiquinone anion QB-. The infrared spectral features attributed to the S1-to-S2 transition of the Mn cluster at room temperature show striking similarity to the S2/S1 difference spectrum measured at cryogenic temperatures (Noguchi, T., Ono, T.-A., and Inoue, Y. (1995) Biochim. Biophys. Acta 1228, 189-200).

Role of phosphorylation in determining the backbone dynamics of the serine/threonine-proline motif and Pin1 substrate recognition

Proline residues provide a backbone switch in a polypeptide chain, which is controlled by the cis/trans isomerization about the peptidyl-prolyl bond. Phosphorylation of serine- and threonine-proline motifs has been shown to be a critical regulatory event for many proteins. The biological significance of these motifs has been further highlighted by the discovery of a novel and essential peptidyl-prolyl cis/trans isomerase Pin1. Pin1 is required for progression through mitosis via catalyzing the isomerization of phosphorylated Ser/Thr-Pro motifs specifically present in mitosis-specific phosphoproteins. However, little is known whether the phosphorylation regulates the conformational switch of the Ser/Thr-Pro bonds. Here, we report the synthesis and conformational characterization of a series of peptides that contain the phosphorylated or nonphosphorylated Ser/Thr-Pro motifs. Phosphorylation affected the rate of the cis to trans isomerization of the Thr/Ser-Pro bonds. As determined by a protease-coupled assay, the isomerization rate of phosphorylated Thr-Pro bond was found to be 8-fold slower than that of the nonphosphorylated analogue. Furthermore, studies of the pH dependence of the isomerization of the phosphopeptides reveal that both cis content and the rate constant of prolyl cis to trans isomerization are lower for the dianionic state of the phosphothreonine-containing peptides. These effects of phosphorylation are specific for phosphorylated Ser/Thr since neither phosphorylated Tyr nor glutamic acid was able to affect the prolyl isomerization. Finally, our experiments provide evidence that effective catalysis of cis/trans isomerization of phosphorylated Ser/Thr-Pro bonds by Pin1 is specific to the dianionic form of the substrate. Thus, our results demonstrate that protein phosphorylation specifically regulates the backbone dynamics of the Ser/Thr-Pro motifs and that Pin1 specifically isomerizes the certain conformation of the phosphorylated Ser/Thr-Pro motifs.

Effects of FK506-binding protein 12 and FK506 on autophosphorylation of epidermal growth factor receptor

FK506-binding proteins and cyclophilins are intracellular proteins that express peptidylproline cis-trans-isomerase (PPIase) activity. The effects of FK506-binding protein 12 (FKBP12) and the cyclophilins 18 and 23 on autophosphorylation of the epidermal growth factor (EGF) receptor prepared from plasma membranes of the human epidermoid cell line A431 have been investigated. Whereas FKBP12 inhibited EGF receptor tyrosine kinase activity in a concentration-dependent manner, the cyclophilins did not affect autophosphorylation. In contrast to the wild-type enzyme, several variants of FKBP12 with greatly reduced PPIase activity were unable to suppress EGF receptor tyrosine kinase significantly. Pervanadate an inhibitor of protein tyrosine phosphatases, abolished the effect of FKBP12 on EGF receptor autophosphorylation. Finally, FK506 and rapamycin, which are known to block the PPIase activity of FKBP12, induced a significant stimulation of EGF receptor autophosphorylation in intact A431 cells suggesting suppression of EGF receptor autophosphorylation by intracellular FKBP12 in vivo. Taken together the data point to an inhibitory function of FKBP12 in EGF receptor signaling, possibly induced by stimulation of a protein tyrosine phosphatase coupled to the EGF receptor. Both PPIase activity and substrate specificity of FKBP12 seem to be indispensable for this effect.

The mode of action of peptidyl prolyl cis/trans isomerases in vivo: binding vs. catalysis

Polypeptides often display proline-mediated conformational substates that are prone to isomer-specific recognition and function. Both possibilities can be of biological significance. Distinct families of peptidyl prolyl cis/trans isomerases (PPIases) evolved proved to be highly specific for proline moieties arranged in a special context of subsites. Structural and chemical features of molecules specifically bound to the active site of PPIases served to improve catalysis of prolyl isomerization rather than ground state binding. For example, results inferred from receptor Ser/Thr or Tyr phosphorylation in the presence of site-directed FKBP12 mutant proteins provided evidence for the crucial role of the enzymatic activity in downregulating function of FKBP12.

Leukemia-free survival and mortality in patients with refractory or relapsed acute leukemia given marrow transplants from sibling and unrelated donors

Between April 1982 and February 1997 39 patients (24 male, 15 female) with refractory acute leukemia and a median age of 31 years (19-51 years) received allogeneic marrow grafts from an HLA-identical sibling (n = 27), HLA-identical unrelated donor (MUD; n = 10) or 1-antigen mismatched unrelated donor (n = 2). Twenty-eight patients had acute myelogenous leukemia and 11 acute lymphoblastic leukemia. For conditioning most patients received total body irradiation combined with cyclophosphamide (n = 23) or etoposide (n = 7). For graft-versus-host disease prophylaxis patients received cyclosporin A (CsA) and methotrexate (MTX) (n = 20), MTX alone (n = 3), CsA and methylprednisone (n = 6), or CsA alone (n = 10), respectively. As of June 1997 probability of leukemia-free survival projected to 3 years after BMT was 14% for patients given sibling marrow grafts and 28% after MUD transplantation. Transplant-related mortality projected to 3 years was 32% after sibling and 37% after MUD marrow grafting. Although not significantly different, probability of relapse projected to 3 years after BMT was lower after MUD at 56% compared to 78% with sibling BMT. Thus, high-dose chemo/radiotherapy followed by allogeneic marrow infusion has a curative potential for patients with refractory leukemia and offers the chance of long-term disease-free survival for some patients.

Semiautomated microtiter plate assay for monitoring peptidylprolyl cis/trans isomerase activity in normal and pathological human sera

An UV/VIS spectrophotometric assay technique was developed that was able to routinely monitor peptidylprolyl cis/trans isomerase (PPIase) activity of biological fluids in 96-well microtiter plates. The assay, based on monitoring the cis-to-trans isomerization of succinyl-Phe-cisPro-Phe-4-nitroanilide as substrate in a chymotrypsin-coupled reaction, yields a throughput of 96 samples per 30 min. The assay's capacity was exemplified by dealing with the PPIase activity in several normal and pathological human sera. Reference values of 151 healthy subjects (83 females, 69 males, 17 to 60 years old) were found to possess significant sex-specific differences. PPIase activity factor K of the sera was significantly greater in males (5th, 50th, 95th percentiles: 17, 36, 55 K) than females (14, 30, 48 K). PPIase activities of sera from healthy donors (n = 151) were significantly higher (Mann-Whitney rank-sum test P < 0.0001) than those of patients (n = 47). PPIase activity in serum samples stored at 4 degrees C was stable for at least 20 h.

Prolyl isomerases do not catalyze isomerization of non-prolyl peptide bonds

Prolyl isomerases accelerate the cis <--> trans isomerization of prolyl peptide bonds during protein folding and probably also in folded proteins. We asked whether this catalytic function is in fact restricted to prolyl bonds or whether the isomerizations of 'normal' non-prolyl peptide bonds are catalyzed as well. By using the P39A variant of ribonuclease T1 as a substrate we find that the trans --> cis isomerization of the Tyr38-Ala39 bond in the refolding of this protein is not catalyzed by prolyl isomerases of the cyclophilin, FKBP and parvulin families. These enzymes are neither able to catalyze amide bond isomerizations in the proline-free model peptide Ala-Ala-Tyr-Ala-Ala.

Replication of the linear chromosomal DNA from the centrally located oriC of Streptomyces ambofaciens revealed by PFGE gene dosage analysis

From a cosmid clone of Streptomyces ambofaciens containing the dnaA and gyrAB genes, a 2.7-kb self-replicating DNA fragment containing the chromosome replication origin oriC was isolated. This cosmid was previously maped physically to a region near the middle of the 8-Mb linear chromosomal DNA. A pulsed-field gel electrophoresis time-course analysis revealed that sequences flanking oriC were overrepresented relative to the rest of the chromosomal DNA during rapid growth, indicating that this origin is active. In addition, the terminal regions of the chromosomal DNA showed a slight overrepresentation at the onset of stationary phase.

Evidence for the absolute conformational specificity of the intestinal H+/peptide symporter, PEPT1

This study was initiated to determine whether the intestinal H+/peptide symporter PEPT1 differentiates between the peptide bond conformers of substrates. We synthesized a modified dipeptide where the peptide bond is replaced by the isosteric thioxo peptide bond. The Ala-Pro derivative Ala-psi[CS-N]-Pro exists as a mixture of cis and trans conformation in aqueous solution and is characterized by a low cis/trans isomerization rate. The compound was recognized by PEPT1 with high affinity. The Ki value of Ala-psi[CS-N]-Pro for the inhibition of the uptake of radiolabeled glycylsarcosine in Caco-2 cells was 0.30 +/- 0.02 mM, determined in solution with 96% trans conformation. In contrast, the Ki value was 0.51 +/- 0.02 mM when uptake media with 62% trans conformer were used. We conclude that only the trans conformer interacts with the transport system. From our data, a significant affinity of the cis conformer at PEPT1 cannot be derived. In a second approach, conformer-specific uptake of Ala-psi[CS-N]-Pro was studied by analyzing the intracellular content of Caco-2 cells following transport as well as the composition of the extracellular medium using capillary electrophoresis. The percentage of trans conformer that was 62% in the uptake medium increased to 92% inside the cells. This is the first direct evidence that an H+/peptide cotransport system selectively binds and transports the trans conformer of a peptide derivative.

Giant cephalhaematoma in a 17-year-old boy with Ehlers-Danlos syndrome

We report a case of giant cephalhaematoma in a 17-year-old boy with Ehlers-Danlos syndrome. This haematoma occurred after a minor head injury. It increased in size, immediately after needle aspiration and was responsible for considerable blood loss. Possible physiopathological mechanisms and treatment modalities are discussed.

Analytical validation of the BEM--application of the BEM to the electrocardiographic forward and inverse problem

The objective of this study is to analytically validate a boundary element (BE) formulation for the relationship between the transmembrane potential on the heart's surface and the potential on the body surface applying a concentric spherical test geometry. The relative difference (reldif) between the potential on the outer sphere of the test geometry computed analytically and numerically is determined by 3.59% for the coarse discretization (48 BEs) and by 0.46% in the case of the finer subdivision (192 BEs). In the inverse problem, the transmembrane potential on the inner sphere is estimated numerically from the electric potential on the outer sphere by using a minimum-norm least-square approach. The relative differences found are 20.2% when no measurement noise is added and 26.4% in the presence of 2% additional Gaussian noise. The BE formulation is also applied to real world data for solving the electrocardiographic inverse problem. A normal volunteer's inhomogeneous thorax (outer thorax surface, surfaces of the lungs, epicardial heart surface) is modelled by 424 BEs. The same inverse method is then applied in order to reconstruct the transmembrane potential on the epicardium from the measured body surface potential (BSP) data during normal ventricular depolarisation.

Separation of cis/trans conformers of human and salmon calcitonin by low temperature capillary electrophoresis

Conformer-specific recognition of peptides and proteins has often been proved with the aid of indirect methods. Here we provide an analytical approach for a direct investigation of separated isomers. Cis/trans conformers of the peptide hormones human (hCT) and salmon (sCT) calcitonin exhibit different migration properties in capillary zone electrophoresis at subambient temperatures. Calcitonin consists of 32 amino acids with two proline residues incorporated. It is the longest unstructured peptide for which a conformer separation by capillary electrophoresis has yet been achieved. Lowering the temperature yielded a splitting into two and three peaks for sCT and hCT, respectively, in acidic buffer. The peak ratios of 66:34 for sCT and 71:23 for hCT are in good agreement with the conformer distribution previously reported from nuclear magnetic resonance (NMR) studies. The addition of different organic modifiers (5-20% v/v) to the running buffer does not improve the separation. The observed merging of conformer peaks in buffer containing 20% v/v 2,2,2-trifluoroethanol (TFE) is attributed to structure formation.

Consanguinity in question in two patients with congenital adrenal hyperplasia who bear an identical first and last name--second look

Two patients with identical first and last name, both suffering from Congenital Adrenal Hyperplasia due to 21-hydroxylase deficiency, were investigated in our endocrine outpatient unit. The families of the two girls did not know of each other's existence. Although paternal ancestors were identified up to the 11th and 9th previous generations, respectively, and a common area of origin, roughly 50 km apart, in the northwestern part of the Czech Republic (formerly Austrian Silesia) was established, no common ancestor was found. The patients' respective paternal CYP 21B allele was identical. However, by means of analysis of class I-and class II-HLA regions in both patients and their respective parents no common paternal haplotype was established. In order to still postulate consanguinity by the same paternal haplotype it is necessary to assume that two recombinations in the HLA region must have occurred. The probability that these two events have taken place within the past 11 generations is 0.11%.