Search PubMed⌕ Search

Biomedical subjects

C Pappas

Publications and source records attributed to C Pappas.

At least 37 records · Page 2Linked to original sources
PubMed1998

An integrated environment for ECG processing.

The huge amount of information involved in clinical cardiological examination raises the need for efficient patient data management and for the fusion of modern information processing techniques in the everyday clinical workstation. An integrated medical information system has been developed in order to organize the local cardiological legacy system in the AHEPA hospital. An ODBC based database (like Ms SqlServer or MSAccess) holds patient and ECG data. The system incorporates data management (storing and retrieval) and data processing modules. The processing module is added as an independent DLL. The visualization component results in a better view of the information. The components are integrated in a friendly window interface that lets the doctor browse patient information, apply modern signal processing techniques, make special measurements and store them in the database for research reasons.

Database Management Systems↗
PubMed1997

Identification of computer-generated facial composites.

Two studies examined the effectiveness of the Mac-a-Mug Pro, a computerized facial composite production system. In the first study, college freshmen prepared from memory composites of other students and faculty from their former high schools. Other students who had attended the same high schools could not recognize the composites of either students or faculty members when the composites of individuals known to them (n = 10) were mixed with composites of a large number (n = 40) of strangers. Neither preparer familiarity with the target, preparer-assessed composite quality, nor viewer familiarity predicted composite recognition. Study 2 indicated that naive witnesses who viewed the composites could not select the people depicted in the composites from photo lineups (1 target and 4 foils). The results raise questions about the efficacy of composite systems as tools to promote recognition of suspects in criminal contexts.

Adolescent↗
PubMed1997

RHINE-AM. An inter-regional health information network for Europe.

RHINE is an inter-regional network in Europe having as an aim, the promotion of know-how transfer in the area of Information Technology methods and tools in the regions involved. The RHINE network's significance will be demonstrated in the health sector. Within the main scope of the project, the aims and objectives of RHINE and the participating partners encompass the extension of the nucleus network and the furtherance of Information Technology research. Application areas include distributed data base and knowledge base technologies for open regional information systems supported by other technologies for business processes.

Computer Communication Networks↗
PubMed1997

Coronary artery skeleton detection based on topographic features.

A new approach to the problem of detecting the skeletons of coronary arteries in coronary angiograms is proposed. The digitized grayscale coronary angiograms are regarded as noisy sampling of the underlying continuous surface. After the application of Gaussian filtering to reduce noise, the topographic features of the smoothed image are detected based on first and second order image derivatives. Then, the candidate arteries skeleton points are detected based on the observation that arteries are smooth elongated objects having approximately a Gaussian smoothed semi-elliptical profile. Experimental results on real digitized coronary angiograms are presented.

Algorithms↗
PubMed1996

Clinical evaluation of the DIABETES expert system for decision support by multiple regimen insulin dose adjustment.

A performance evaluation of the DIABETES rule-based expert system prototype for clinical decision making is presented. The system facilitates multiple insulin regimen and dose adjustment of insulin dependent Type I or II diabetic patients. The study was performed on 600 subjects from two diabetological centres and three diabetological offices of Greek hospitals. The responses of the attendant medical doctors were compared with those of the DIABETES system, with the aid of a specifically devised valuation range (0-5 degrees, 0 indicating full agreement and 5 full disagreement). The capabilities and the weakness of the system in terms of its practicality for decision support in assisting therapy of diabetes mellitus by blood glucose monitoring and subsequent insulin dose adjustment are discussed. The potential benefits of decision support systems for diabetic patient management are seen to be the cost saving they provide in terms of man-hours of verbal instruction by medical experts, the support in terms of objective and consistent decision making, as well as the recording of medical knowledge in the ill-defined field of insulin administration, thus aiding the education and training of medical personnel.

Aged↗
PubMed1996

Cardiological database management system as a mediator to clinical decision support.

An object-oriented medical database management system is presented for a typical cardiologic center, facilitating epidemiological trials. Object-oriented analysis and design were used for the system design, offering advantages for the integrity and extendibility of medical information systems. The system was developed using object-oriented design and programming methodology, the C++ language and the Borland Paradox Relational Data Base Management System on an MS-Windows NT environment. Particular attention was paid to system compatibility, portability, the ease of use, and the suitable design of the patient record so as to support the decisions of medical personnel in cardiovascular centers. The system was designed to accept complex, heterogeneous, distributed data in various formats and from different kinds of examinations such as Holter, Doppler and electrocardiography.

Cardiovascular Diseases↗
PubMed1995

Activation delay in healed myocardial infarction: a comparison between model and experiment.

Conduction delay in healed myocardial infarction, facilitating reentry, is frequently based on an increased path length the activation has to travel in a matrix of merging and diverging bundles that survive in the infarcted area. Additional delay occurs at sites where bundles bifurcate. The purpose of this study was to investigate conduction delay at sites where bundles bifurcate. A computer model was developed to simulate spread of activation in a two-dimensional sheet of excitable elements. A structure consisting of two isolated bundles merging into a single one was modeled. Extracellular electrograms calculated in the model were comparable to electrograms obtained in a superfused infarcted papillary muscle model. A zone of crowded isochrones or local conduction delay was found at the site where an isolated bundle bifurcated. The position of the isochrones in this area depended on the way activation times were determined. Lines of activation delay were mainly perpendicular to the fiber direction. In conclusion, the results have enabled us to better understand extracellular electrograms at pivoting points and show that activation sequences at a microscopic level can best be constructed on the basis of Laplacian signals.

Computer Simulation↗
PubMed1995

Successful treatment of hyponatremia with angiotensin-converting enzyme inhibitors in patients with congestive heart failure.

Hyponatremia commonly complicates the clinical course of patients with congestive heart failure (CHF) and seems to be an ominous prognostic factor. Angiotensin-converting enzyme (ACE) inhibitors improve the symptomatology of CHF patients. Moreover, it has been reported that these drugs can raise serum sodium in hyponatremic patients. The aim of this prospective work was to study the mechanisms involved in the correction of hyponatremia in 6 patients aged 52-69 years with CHF and hyponatremia (serum sodium 125-128 mmol/l) who were receiving digitalis and furosemide. In these patients, captopril was introduced in progressively increasing doses. The drug induced significant clinical improvement. Additionally, a statistically significant increase in serum sodium was observed which was correlated to a rise in the diluting ability of the kidney (increase in CeH2O). A slight increase in creatinine clearance was also found, which could have contributed to the improvement in hyponatremia. Therefore, we conclude that ACE inhibitors can improve hyponatremia in CHF patients by increasing the urinary diluting ability.

Aged↗
PubMed1993

Survival of Salmonella enteritidis during the manufacture of feta cheese made of pasteurized ewe's milk.

The behaviour of Salmonella enteritidis during the Feta cheese making process was investigated. Two lots of pasteurized whole ewe's milk were inoculated to contain 10(6) cfu/ml of S. enteritidis (strain AS1 and AS2) and were processed into Feta cheese following standard procedures. All samples were examined for S. enteritidis both quantitatively and qualitatively, while moisture, fat, water activity and pH were also measured. S. enteritidis was enumerated in duplicate samples by surface plating on SS agar. Selected salmonella-like colonies were identified biochemically and serologically. The enumerations have shown that S. enteritidis was initially entrapped in the curd. Then the growth of S. enteritidis gradually decreased and no Salmonellae were quantitatively enumerated after the 23rd day. However S. enteritidis was detected qualitatively in samples taken until the 38th day.

Animals↗
PubMed1992

Spironolactone pharmacokinetics and pharmacodynamics in patients with cirrhotic ascites.

The intent of this study was to identify pharmacokinetic and pharmacodynamic characteristics for spironolactone (SP) and its metabolites (canrenone, 6 beta-hydroxy-7 alpha-thiomethylspirolactone, 7 alpha-thiomethylspirolactone) in cirrhotics under steady state conditions. Nine cirrhotics with ascites participated in the study. Serial blood samples were drawn and urine was collected over a 26-hour period. Using a reverse-phase high performance liquid chromatography (HPLC) method, all samples were analyzed for SP, canrenone, 6 beta-hydroxy-7 alpha-thiomethylspirolactone, and 7 alpha-thiomethylspirolactone concentrations. Parent compound and metabolite urinary excretion rates as well as maximal concentrations and time at which these are observed were calculated. The apparent median terminal elimination rate constants (associated half-lives) were 0.0767 h-1 (9.04 hours) for SP, 0.0055 h-1 (126 hours) for 6 beta-hydroxy-7 alpha-thiomethylspirolactone, 0.029 h-1 (23.9 hours) for 7 alpha-thiomethylspirolactone and 0.012 h-1 (57.8 hours) for canrenone. SP metabolism is impaired in cirrhosis; terminal half-lives of SP and metabolites appear to be increased when compared with values reported in the literature for normals. When assuming a linear model, clearance-effect relationship estimates are best correlated with 7 alpha-thiomethylspirolactone and canrenone. Further research is required to identify specific pharmacokinetic and pharmacodynamic parameters for SP and its metabolites in this patient population.

Adult↗
PubMed1991

Cellular mechanisms of Cl- transport in outer medullary collecting duct.

The OMCDi secretes Cl- when perfused and bathed with symmetrical solutions. The route for this transepithelial Cl- movement appears to be the paracellular pathway, and the driving force is the lumen positive voltage generated by the process of electrogenic H+ secretion. Currently, there is no evidence to support the existence of a significant transcellular route for transepithelial Cl- movement. Although the primary function of the OMCDi is related to urine acidification, Cl- plays an important role in this process. The basolateral membrane of the OMCDi cell contains a band-3 related Cl-/HCO3- antiporter and a Cl- conductance. The Cl-/HCO3- antiporter serves as the primary route for the efflux of HCO3- generated during the process of H+ secretion. The Cl- conductance allows Cl- brought into the cell by the antiporter to recycle across this membrane. This conductance also serves to maintain cell charge balance. Accordingly, for each equivalent of H+ leaving the cell across the apical membrane, a Cl- equivalent exits the cell across the basolateral membrane. Based on whole-cell patch-clamp studies, this Cl- conductance is blocked by the Cl- channel blocker DPC. This conductance may also have a finite permeability to HCO3-, and thus could serve as a secondary route for cellular HCO3- efflux. Lastly, the conductance is activated by the beta-adrenergic agonist isoproterenol.

Animals↗
PubMed1990

Cerebral venous malformations.

Although cerebral venous malformations have been reported to cause epilepsy, progressive neurological deficits, and hemorrhage, their clinical significance remains controversial. In an attempt to clarify the natural history of the lesion and suggest an appropriate management strategy, the authors review their experience with 30 patients. In four patients with cerebellar venous angioma, an acute episode of ataxia was documented. The coexistence of a cavernous malformation was pathologically confirmed in the two patients who underwent surgery for bleeding presumed caused by the venous angioma. Infarction was shown in two patients and a tumor in two others. Follow-up periods ranged between 18 and 104 months, with only five patients symptomatic at the time of this report. Rebleeding had not occurred, nor had acute episodes of neurological dysfunction been documented. This clinical experience suggests that a venous malformation is frequently associated with other, more symptomatic conditions and is often erroneously identified as the source of the symptoms. Because the nature of the relationship between the venous malformation and the allied conditions remains ambiguous, it is recommended that patients harboring a "symptomatic" venous malformation undergo high-field magnetic resonance imaging to rule out underlying pathology, and that any such pathology be treated independently of the venous malformation.

Adolescent↗
PubMed1984

Congenital Plasmodium vivax malaria.

A case of congenitally acquired Plasmodium vivax malaria in an infant of a Vietnamese refugee is reported. The pathogenesis and treatment of congenital malaria are also discussed briefly. As many Southeast-Asian refugees are now emigrating to Australia, physicians should be aware of this rare form of malaria.

Adult↗