Biomedical subjects

I Repa

Publications and source records attributed to I Repa.

At least 37 records · Page 2Linked to original sources

PubMed2000

Lung water and proton magnetic resonance relaxation in preterm and term rabbit pups: their relation to tissue hyaluronan.

The present study was performed to investigate simultaneously total lung water, T(1) and T(2) relaxation times, and hyaluronan (HA) in preterm and term rabbits. Attempts were also made to establish the relationship of HA to total lung water and to T(2)-derived motionally distinct water fractions. Experiments were performed in fetal Pannon white rabbit pups at gestational ages of 25, 27, 29, and 31 d and at a postnatal age of 4 d. Lung tissue water content (desiccation method), T(1) and T(2) relaxation times (H(1)-NMR method), and HA concentration (radioassay) were measured, and free and bound water fractions were calculated by using multicomponent fits of the T(2) relaxation curves. Lung water content and T(1) and T(2) relaxation times were highest at a gestational age of 27 d and then declined steadily during the whole study period. Similar trends and time courses were seen for the fast and slow components of the T(2) relaxation curve. The T(2)-derived free water fraction remained unchanged at a gestational age of 25-29 d ( approximately 67%), but increased progressively to a value of 78.5 +/- 7.9% at 31 d (p < 0. 001) and to 83.4 +/- 9.4% at the postnatal age of 4 d (p < 0.01). Opposite changes occurred in the bound water fraction. Lung HA concentration decreased with advancing gestation from 870.8 +/- 205.2 microg/g dry weight at 25 d to 162.6 +/- 32.4 microg/g dry weight at 31 d (p < 0.001), but it was increased 2-fold postnatally. HA correlated positively with total lung water (r = 0.39; p < 0.001) but not with the bound water fraction. It is suggested that the physiologic lung dehydration is associated with macromolecule-related reorganization of lung water and that the role of HA in this process needs to be further investigated.

Aging↗

PubMed1999

Brain adaptation to water loading in rabbits as assessed by NMR relaxometry.

The present study was undertaken to investigate the cerebral adaptation to hypoosmolar stress in adult Pannon white rabbits by applying proton nuclear magnetic resonance relaxometry. Progressive hyponatremia was induced by combined administration of hypotonic dextrose in water and 8-deamino-arginine vasopressin over a hydration period of 3, 24, and 48 h. Each group comprised five animals. After completing the hydration protocols, blood was taken to determine plasma osmolality (freezing point depression) and sodium concentration (ion-selective electrode) and, at about the same time, T2-weighted images were made. After the in vivo measurements, the animals were killed and brain tissue samples were obtained to measure water content (desiccation method) and T1 and T2 relaxation times (proton nuclear magnetic resonance method). Free and bound water fractions were calculated by using multicomponent fits of the T2 relaxation curves. It was shown that brain water content and T1 relaxation time remained unchanged despite the progressing hyponatremia. By contrast, T2 relaxation time increased steadily from the control value of 100.2 +/- 7.7 ms to attain its maximum of 107.5 +/- 8.5 ms (p < 0.05) after 48 h of hydration. Using biexponential analysis, fast and slow components of the T2 relaxation curve could be distinguished that corresponded to the bound (T21) and free (T22) water fractions. In response to hyponatremia, the bound water fraction was markedly depressed from 6.5 +/- 3.0% to 3.6 +/- 0.9% (3 h, p < 0.05) and 3.9 +/- 0.8% (24 h, p < 0.05); then it approached the initial value of 5.3 +/- 2.5% by the end of the hydration period of 48 h. It is concluded that restructuring of brain water is a contributory factor to the successful adaptation to hypotonic environment.

Adaptation, Physiological↗

PubMed1999

The role of CT examination in diagnostics and surgery of chronic empyema thoracis.

Computer tomography (CT) has become one of the most important modern diagnostic procedure in the detection, differential diagnosis, treatment and the postoperative follow up of patients suffering from chronic intrathoracic suppuration. Although CT examination is nowadays almost unlimitedly available it is still not regarded as a routine diagnostic procedure. It proves to be remarkably useful in the surgical treatment of neglected, chronic cases of suppuration in the thoracic cavity. On the basis of the Moores empyema thoracis classification [3] patients in the third stage belong to the group with chronic intrathoracic suppuration. Their empyema can only be treated by a major surgery or a series of operations.

Adolescent↗

PubMed1999

The position of spiral CT in the complex diagnostics system for pulmonary embolism.

The development of CT technology, the more widespread use of spiral CT and the application of contrast injection techniques now enable such levels of contrast intensity in the segmental and larger pulmonary arteries to be attained as to allow the minimally invasive, direct detection of emboli. This technique has a role to play in the strategy for check-up examinations for pulmonary embolism. By providing a realistic alternative the spiral CT examination serves to reduce the number of scintigraphy examinations to be performed. At the same time, the role played by invasive pulmonary angiography examinations is now shifting towards intervention.

Aged↗

PubMed1998

[Magnetic resonance cholangiography: our first experience].

Magnetic resonance cholangiography is a new field of clinical application within MR imaging, enabling high-quality imaging on disorders of the pancreaticobiliary system. This cross-sectional imaging technique is, by means of postprocessing, suitable for the production of reconstruction images appropriate for comparison with endoscopic retrograde cholangiography. The quality of the images thus obtained is dependent upon the level of development of the technology and software available. Observations arising from authors initial examinations using 2D fast spin echo sequence are summarised.

Biliary Tract Diseases↗

PubMed1998

Water content and proton magnetic resonance relaxation times of the brain in newborn rabbits.

The present study, using proton nuclear magnetic resonance relaxation (H1 NMR) measurements, was undertaken to quantitate water fractions with different mobility in the brain tissue obtained form New Zealand White rabbit pups. Serial studies were carried out at the postnatal age of 0-1, 24, 48, 72, and 96 h in pups nursed with their mothers and suckling ad libitum (group I) and in those pups separated from their mothers and completely withheld from suckling (group II). Tissue water content (desiccation method) and T1 and T2 relaxation times (H1 NMR method) were measured. Free, loosely bound, and tightly bound water fractions were calculated by applying multicomponent fits of the T2 relaxation curves. It was demonstrated that brain water content and T1 and T2 relaxation times did not change with age in the suckling pups. In pups withheld from suckling brain water decreased from 89.4 +/- 0.5% at birth to 87.7 +/- 0.1% at the age of 96 h (p < 0.05), T1 remained unchanged, and there was a significant fall in T2 by the age of 72 h (188 +/- 12 versus 178 +/- 4 ms, p < 0.05) and 96 h (171 +/- 6 ms, p < 0.01). Partition of brain water into bound and free fractions as derived from biexponential fits of T2 decay curve showed that the percent contribution of bound water fraction in pups of group I fell progressively from 61% at birth to 3% at the age of 72-96 h (p < 0.05). This fall was accelerated by the complete deprival of fluid intake, and the level of about 4% could be attained as early as the age of 24 h. Triexponential analysis of T2 relaxation curves revealed that the loosely bound fraction (middle component) predominated over the free (slow component) and the tightly bound (fast component) water fractions. In response to withholding fluid intake, the free water fraction increased 4-fold at the expense of tightly bound brain water. It is concluded that the majority of neonatal brain water is motion-constrained. The free, the loosely bound, and the tightly bound water fractions appear to be interrelated; from the brain water store water can be released to supply free water for volume regulation.

Age Factors↗

PubMed1997

[Method and use of intracranial cine MR imaging].

The authors introduce a dynamic, non-invasive MR method for the examination of liquorspaces and liquor flow in 221 patients. This method is suitable not only for a dynamic imaging of liquor-flow but also for the semi-quantitative evaluation of flow through the aqueduct. This later measurement can help to select the shuntresponsive NPH cases as well. Cine MR examination along with the routine protocol seems to be most helpful in the differential-diagnostics of different hydrocephalus cases.

Humans↗

PubMed1997

[Image fusion of different tomographic methods (PET/CT/MRI) effectively contribute to therapy planning].

Image fusion (and image registration) is a fundamental topic of three-dimensional (3D) medical image processing. The need to register different imaging modalities arises for several reasons: some anatomical details, especially soft tissues, are more easily seen in MRI than CT images, but the bony structures are better visualised by CT. The visualisation of any morphological volume with a functional data set which may come from SPECT or PET is a very important method both for research purposes and for routine diagnostics. Our developed programs allowing us to solve image fusion tasks also contained some free available softwares. These packages helped us to start additional software development for more advanced applications having elaborated this way the informatical background of multimodality image processing. This paper presents three oncological applications of the image fusion: PET-CT-MRI registration for 3D radiotherapy planning, PET-MRI registration in planning surgery and metastasis localization. All these registration processes were solved by the landmark-matching registration method.

Decision Making↗

PubMed1997

[Principles of functional MRI imaging and its possibilities in the study of cerebral cortex activation].

While MR imaging of anatomic structures has long been widely appreciated, the emergence of functional magnetic resonance imaging (FMRI) methods for localising brain activity has emerged in the beginning of the 90s. This new MRI technique produces images of activated brain regions by detecting the indirect effects of neural activity on local blood volume, flow and oxygen saturation, and it is a promising new tool for further understanding of the relationships among brain structure, function and pathology. The information revealed by FMRI is partially overlapping with PET and SPECT, but it is non-invasive and has a better spatial and temporal resolution. The authors briefly summarise the concept and basics of FMRI and demonstrate the first successful FMRI examination performed in Hungary. The potential role of FMRI in the clinical practice is presented.

Animals↗

PubMed1997

[Bilateral renal artery stenosis diagnosed during pregnancy].

Bilateral renal artery stenosis was diagnosed noninvasively in the 17th gestational week, in a chronically hypertensive pregnant woman, by renal artery duplex ultrasound examination, MRI and MR angiography. Continuous monitoring of the mother and the fetus was performed. Blood pressure was stabilized by complex antihypertensive therapy, but from the beginning of the third trimester superimposed preeclampsia developed gradually. In the 34th gestational week a 1600-g newborn was delivered by elective cesarean section. The case report draws attention to the significance of the thorough examination of hypertensive women before pregnancy.

Adult↗

PubMed1994

[CT-guided percutaneous drainage in the management of psoas abscesses].

The authors review their first experiences in Hungary with the CT guided percutaneous catheter treatment of psoas abscesses. Diagnostic aspiration from abscess was performed in one patient. Percutaneous catheter drainage of psoas abscess were performed in 4 patients. There were 4 patients with unilateral and 1 patient with bilateral psoas abscess. 4 patients had tuberculous spondylodiscitis, 1 patient had staphylococcal vertebral osteomyelitis. One patient following diagnostic aspiration was successfully treated with antituberculoutic drugs. All patient treated with percutaneous catheter drainage received medical antituberculoutic or antibiotic therapy and showed excellent clinical and radiological results. There was no complication and there was no need to open surgical drainage in this series. CT guided aspiration is a valuable tool in the diagnosis of psoas abscesses as well as in the identification of the exact abscess etiology. Percutaneous drainage represents an efficient and attractive alternative to open surgical drainage in the treatment of psoas abscesses.

Aged↗

PubMed1994

[Percutaneous transluminal angioplasty of the subclavian artery].

Over a period of 12 years, percutaneous transluminal angioplasty was used to dilate 227 subclavian obliterations (216 stenoses, 11 occlusions) in 208 patients. Immediate success rate was 96%. 152 dilated arteries long-term patency are known. The average follow-up time was 32 months (1-120 months). 14 restenosis occurred. In 7 of the 14 patients redilation were performed. Complication: 3 puncture site thrombosis, 1 haematoma, 4 transient confusion occurred. In 2 patients shoulder pain developed with unknown origin, and last for a few weeks. There were no irreversible neurologic deficit. Percutaneous transluminal angioplasty of subclavian artery stenoses should be the procedure of choice in symptomatic patients.

Adult↗

PubMed1993

[The importance of CT-guided needle biopsy in the diagnosis of thoracic diseases].

In the report on 35 CT-guided fine needle transthoracic biopsies the authors show the relevance of invasive radiological methods in tumor diagnostics. The results are compared with those published in the literature. CT-guided transthoracic biopsy is of crucial importance in final diagnosis of certain thoracic diseases.

Biopsy, Needle↗

PubMed1992

[The use of endoprostheses (stents) in airway stenosis].

Six patients with obstruction of the trachea were treated with silicone rubber endothracheal stents implanted with flexible bronchoscope. In every case the stent caused significant clinical improvement of the ventilation. At the postintubation stenosis the stent can result a final recovery, at the malignant processes the implantation seems to be a new palliative method.

Accidents↗

PubMed1992

[Percutaneous transluminal angioplasty in atypical aortic coarctation in an adult patient].

In the reported case, coarctation of the aortic arch (Coa) was the cause of hypertonia. Coa diminishes the expected lifetime, and operative treatment is required. PTA is contradictory in the treatment of coarctation. In the reported case coarctation was located on the aortic arch, and because of the risk of the operation PTA was performed. The dilatation was successful, hypertension resolved, and there was no significant difference in the blood pressure on the extremities. 16 months after the dilatation the patient is symptomless. The result of this case indicates that PTA of the Coa of the aorta is feasible. More experience is needed to establish its role.

Adult↗

PubMed1992

Effects of intravenous streptokinase and CLS 2210 (calcium dobesilate) on the biochemical markers of early acute myocardial infarction: a historic comparison with both studies.

In a previous double-blind, randomized study, CLS 2210 (a new formulation of calcium dobesilate) or placebo was administered by intravenous infusion to 41 patients having their first acute myocardial infarction. In the present study 19 comparable patients were treated intravenously with streptokinase under identical conditions and the results compared with those from the previous study. In all patients administration was begun within three hours of onset of symptoms and continued over seventy-two hours. Blood samples were taken for the measurement of serum activity of creatine kinase and its isoenzyme MB, and the serum and urinary concentrations of myoglobin and glycosaminoglycans were also measured. The purpose of this study was to determine the effects of CLS 2210, placebo, and streptokinase on these biochemical markers of acute myocardial infarction, thereby assessing their actions in limiting myocardial necrosis. In the CLS 2210-treated patients, the levels of serum creatine kinase and serum and urinary myoglobin were significantly lower than in the placebo patients throughout the seventy-two hours (p = 0.01, 0.005, 0.004 respectively). The levels of creatine kinase MB and serum glycosaminoglycan in the CLS 2210 patients were initially higher than in the placebo patients but fell below placebo levels between the fortieth and fifty-fifth hours, respectively (p = 0.89, 0.02). Only the glycosaminoglycan urinary concentrations were higher in the CLS 2210 group than in the placebo group throughout (p = 0.0005). The values for the six variables investigated showed no statistically significant difference between placebo and streptokinase.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzenesulfonates↗

PubMed1991

The influence of CLS 2210 on the course of myocardial infarction: a pilot study in man.

To assess the effect of CLS 2210 (a new formulation of calcium dobesilate) on the evolution of acute myocardial infarction, 100 patients presenting their first infarct were distributed, according to their sequential admissions to the hospital, into CLS 2210-treated group (50 patients) or a comparison group (50 patients not receiving CLS 2210). The two groups were similar in age, sex, predisposing factors, and site of infarction. Intravenous infusion of CLS 2210 was begun within six hours of onset of chest pain and continued for seventy-two hours. Thereafter, it was given, as oral capsules, in a dose of 1,000 mg every eight hours throughout the hospitalization. Before and during the trial, blood samples were drawn for the measurements of serum concentrations of creatine kinase (CK), and twelve-lead electrocardiograms (ECGs) were obtained serially in each patient. All objective data were analyzed on a coded basis without reference to the treatment. In the comparison group, thirty-six to forty-eight hours was required for CK to fall to 50% of the baseline value, whereas in the CLS 2210-treated group it reached 50% of the baseline in eighteen to twenty-four hours. For each infarction site, a statistically significant fall was reached earlier in the CLS 2210 group. CK, the ECG index, and the sum of the ST segments showed earlier and more rapid improvement in the CLS 2210 group than in the comparison group. The consumption of narcotic analgesic agents and nitroglycerin was substantially less in the CLS 2210 group than in the comparison group.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzenesulfonates↗

PubMed1990

Calcium dobesilate (CLS 2210) protects the myocardium in early acute myocardial infarction: a preliminary randomized, double-blind, placebo-controlled study of its effects on biochemical markers.

To determine the effect of calcium dobesilate (CLS 2210) on biochemical markers of acute myocardial infarction, and thereby assess its action in limiting myocardial necrosis, this compound was administered intravenously by a randomized, double-blind technique to 23 of 41 patients suffering their first infarction. The remaining 18 patients received a placebo. Administration was begun within 3 h of onset of symptoms and continued for 72 h. Before and during treatment, blood samples were taken for measurement of the serum activity of creatine kinase and its isoenzyme MB, and the serum and urinary concentrations of myoglobin and glycosaminoglycans. Serum creatine kinase and serum and urinary myoglobin were significantly lower in the CLS 2210-treated patients than in the placebo patients throughout the 72 h (p = 0.01, 0.005, and 0.004, respectively). Serum creatine kinase MB and serum glycosaminoglycan in the CLS 2210 patients were initially higher than in the controls, but fell below the control levels between the 40th and 55th hours (p = 0.89 and 0.02, respectively). The glycosaminoglycan urinary concentrations alone were higher in the CLS 2210 group than in the placebo group throughout (p = 0.0005). These findings suggest that CLS 2210 reduces myocardial infarct size in human subjects, as it is already known to do in animals.

Acute Disease↗