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Biomedical subjects

J Novotný

Publications and source records attributed to J Novotný.

At least 55 records · Page 3Linked to original sources
PubMed1999

Resolution and identification of Gq/G11alpha and Gialpha/Goalpha proteins in brown adipose tissue: effect of cold acclimation.

Levels of guanine nucleotide-binding proteins G(q)alpha and G(11)alpha, which produce receptor regulation of phospholipase C, were measured immunologically in purified plasma membrane fractions of hamster brown adipose tissue (BAT). This was achieved by immunoblotting with antisera (CQ series) that identify these two polypeptides equally, following separation of the plasma membranes using SDS-PAGE in the presence of 6 M urea, i.e. conditions that can resolve G(q)alpha and G(11)alpha. The ratio of levels of G(q)alpha to G(11)alpha was 1:1. A similar approach was used for resolution and identification of G(o)1alpha and G(o)2alpha, the latter representing the prevailing form of G(o)alpha proteins in this tissue. Although clearly recognized in brain microsomes, which were used as positive controls, no detected levels of G(o)*alpha protein were noted. Using specific anti-peptide antibodies directed against the carboxy-terminal decapeptide of G(i)3alpha, this G protein was also found to be expressed in BAT tissue. Cold acclimation resulted in reduction of the plasma membrane levels of all these Galpha proteins.

Adaptation, Physiological↗
PubMed1999

A case of a pulmonary arteriovenous malformation treated by lobectomy.

We present a case of pulmonary arteriovenous malformation (PAVM) in central localisation (type IIIa) of the upper lobe of the left lung. We discuss diagnostic (Doppler ultrasonography, CT, MRI, angiography) and therapeutic (embolization therapy) options and a current role of surgery in this uncommon clinical condition. Our patient underwent left upper lung lobectomy as an ultimate therapeutic method without subsequent morbidity. We conclude that surgery is a safe method of treatment of pulmonary arteriovenous malformations in selected cases i.e. when PAVM is solitary and of great diameter (more than two centimeters) and where the risks of embolotherapy are high.

Arteriovenous Fistula↗
PubMed1999

Adverse drug reactions to antibiotics and major antibiotic drug interactions.

Adverse drug reaction and drug interactions represent negative consequences of pharmacotherapy. A thorough knowledge of how the adverse reactions and drug interactions occur will aid in our ability to provide the best patient care possible. Adverse drug reactions and drug interactions are defined and mechanisms of their occurrence are discussed; ways to identify, assess, manage, and report these reactions are presented. The importance of postmarketing surveillance is highlighted. A thorough understanding of the mechanism of adverse drug reactions and drug interaction is essential for the health care practitioner. Improved patient care can be achieved by applying this knowledge to the individual patient. When drugs are administered to patients, many things can go wrong. The magnitude of this problem warrants spending sufficient resources to establish programs to identify, assess, and manage these reactions. Having effective reporting programs will help prevent many reactions and will provide earlier detection of adverse reactions to new drugs.

Anti-Bacterial Agents↗
PubMed1999

Aneurysm of the subclavian artery.

In this case report about a female patient with a true aneurysm of the left subclavian artery (SAA), the authors would like to present the symptoms, possibilities of diagnostics and management of this rarely appearing pathology. The diagnosis of a randomly found aneurysm in a symptom free patient was confirmed by spiral AGCT. Classical surgical procedure was indicated for the patient. With a combined supra- infraclavicular approach the partial resection of the aneurysm and its revascularization by a ePTFE prosthetic interposition were performed. A histological investigation showed nonspecific changes in the aneurysm wall. Two years after the operation the patient is without any complications and with complete functional vascular reconstruction and optimal limb function.

Aneurysm↗
PubMed1999

[Radiosurgery with the Leksell gamma knife in the treatment of solitary brain metastasis--5-year results].

During five years (1992-1997) 215 patients with solitary brain metastases were treated in the Department of Stereotactic and Radiation Neurosurgery (117 men and 98 women). The most frequent first neurological symptoms were: headache, hemiparesis, seizure, mental and behavioural disturbances. Location of lesion was supratentorial in 163 patients (75.8%) and infratentorial in 52 cases (24.2%). Treatment results: complete and partial regression in 175 patients (81.4%), stabilisation in 30 of patients (14.0%), local progression in 10 patients (4.6%). Local recurrence after initially effective treatment was observed in 11 pts (5.1%). The severity of neurological symptoms was measured by RTOG 4 grades scoring system. The acute and late toxicity was evaluated by SOMA scale (RTOG--Radiation Therapy Oncology Group): grading 0-5. We observed acute toxicity (score 3 and 4) in 20 patients (9.3%) and late (score 3 and 4) in 9 patients (4.2%). Minimal follow up for all patients was 10 months. Median survival for 159 dead patients was 7 months (ranged from 2 to 35 months), median survival for surviving 56 pts was 15.5 months (ranged from 10 to 56 months). One-year survival was 39.5% of all patients.

Adult↗
PubMed1998

[Treatment of febrile neutropenia in patients with solid tumors].

BACKGROUND: Febrile neutropenia (FN) is one of the most serious complications of anti-tumourous treatment calling for early diagnosis and intensive treatment. The objective of the trial was to recommend a standard procedure for the treatment of febrile neutropenia at their Oncological Clinic, based on analyses of attacks of febrile neutropenia and the current microbial situation. METHODS AND RESULTS: In 1995-1997 in 30 patients (24 women, 6 men) 39 attacks of febrile neutropenia were treated. The age distribution of patients was within the range of 20-68 years, the mean age being 50 years. In the group patients with breast cancer predominated (14), soft tissue sarcomas (4), colorectal carcinoma (3), other diagnoses participated with 9 episodes. The analysis of the microbial situation was based on cultivation findings made in patients with attacks of FN. For empirical treatment of FN the authors use at combined treatment piperacillin-gentamicin or sultamicillin-cefpodoxim/or ciprofloxacin. If empirical treatment fails, therapy is based on the results of cultivation and the patient's clinical condition. Growth factors are indicated for treatment only in FN complicated by mycotic infection, inflammatory pulmonary infiltrates or cardiopulmonary failure. CONCLUSIONS: The standard procedure in the treatment of FN should be broad spectrum bactericidial antibiotics. The use of growth factors is reserved for complicated episodes of FN.

Adult↗
PubMed1998

[Heparin-induced thrombocytopenia].

Heparin induced thrombocytopenia is encountered in clinical practice as type I and type II. Heparin induced thrombocytopenia type II is one of the most serious complications of heparin treatment. Its incidence is between 0.5-5% of all patients treated with heparins. Contrary to type I which is most probably caused by simple interaction of heparin with platelets, in type II factors of the immune system are involved. The laboratory diagnosis is complicated and negative, in vitro tests do not rule out the diagnosis in vivo. The latter is assessed most frequently per exclusionem when there is a marked drop of platelets associated with the clinical picture of thrombotic complications. Heparin must then be immediately discontinued and at the same time usually alternative antithrombotic treatment is necessary. Low-molecular heparins are contraindicated by the majority of authors because of possible immunological cross reactions, and coumarins are also unsuitable as drugs of first choice because of their late onset of effect and initial drop of protein C. Ideal preparations are most probably direct thrombin inhibitors (recombinant hirudin and its analogues, oligopetides). Anti-thrombocyte drugs can be used, possibly the defibrination enzyme ancrode (Arwin).

Anticoagulants↗
PubMed1996

Euglena gracilis as a supplementary test organism for detecting biologically active compounds.

The mutagenic activity of more than 120 antimicrobial agents and protective components was investigated. Only Kathon showed a consistent increase in revertant counts in the Ames test on Salmonella typhimurium. The hereditary bleaching test on Euglena gracilis used for detecting extranuclear mutations, showed positive results for Kathon, triethanolamine and diamine silver tetraborate.

Animals↗
PubMed1996

Transportation dose and doses to extracranial sites during stereotactic radiosurgery with the Leksell Gamma knife.

Two dosimetric aspects of Leksell Gamma knife (LGK) treatment have been investigated in this study: (a) measurement of the small dose (transportation dose) which is absorbed during the patient's transportation into and out of the treatment position within the ionization chamber, and (b) measurements of the doses absorbed by the eyes, thyroid, breast, abdomen, gonads, knee and ankle during the treatment using thermoluminescent dosimetry (TLD). The transportation dose was 0.253 +/- 0.003 Gy, which represented 8.4% of the dose rate (3.005 Gy/min) during measurements. In vivo TLD measurements have been performed on 51 patients. The doses measured in organs and sites of interest were 0.223 +/- 0.168 Gy for the eyes, 0.081 +/- 0.050 Gy for the thyroid, 0.049 +/- 0.033 Gy for the breast, 0.024 +/- 0.18 Gy for the abdomen, 0.012 +/- 0.008 Gy for the gonads, 0.003 +/- 0.002 Gy for the knee and 0.002 +/- 0.002 Gy for the ankle. During LGK radiosurgery, doses to extracranial sites and organs depend mainly on the total target dose and the number of shots used for the treatment. These doses are generally low; the maximum dose was measured for the eyes (approximately 0.7% of the maximum target dose), and the doses to other body organs decrease with increasing distance from the isocenter of the LGK radiation unit.

Abdomen↗
PubMed1996

Three-dimensional finite element computer model of the forward problem of electrocardiology.

This study analyses forward problem of electrocardiology. Premature beats originated from subepicardial layer of myocardium were simulated in order to analyse their shape dependence on the site of origin. The equation governing the propagation of the electrical wave through human thorax together with transition and boundary conditions is derived under the clearly stated simplifying assumptions. The weak formulation of the forward problem of electrocardiology is introduced, too. The Galerkin method as a convenient tool for looking for the numerical solution is mentioned and its practical implementation--finite element method--then used in order to obtain numerical results. The obtained results were presented in the form of isopotential maps and compared with actually measured body surface isopotential maps of the depolarization phase. The parameters of the model were then optimalized in accordance with the measured data. In spite of the lack of quantitative data the model has proved that the presented method was able to be used for the simulation studies of ventricular ectopic beats. It was shown that only a small difference between the site of beat origin can be well distinguished on the simulated body surface maps. (Fig. 3, Ref. 3.)

Computer Simulation↗
PubMed1995

[The Leksell gamma knife--a radiosurgery instrument].

Radiosurgery means delivery of a single dose of precisely directed ionizing radiation to a small volume of intracranial tissue without opening of the skull after the stereotactic localisation of the preselected target. Leksell gamma knife is a device enabling to deliver focused radiation toward the intracranial volume with the gamma rays emitted by the 201 sources of the isotope Co 60. Suitable indications for radiosurgery are cerebral arteriovenous malformations, benign and malignant intracranial tumors and functional diseases of the brain.

Brain↗
PubMed1995

[Radiosurgical treatment of meningioma with the Leksell gamma knife].

BACKGROUND: Up to the present time radical microsurgery of the tumour was considered the most satisfactory treatment. Now an ever more important part in the treatment of these tumours is played by radiosurgery. It involves minimal surgical stress, a minimal rate of complications and minimal change of lifestyle during the postoperative period. The objective of the submitted work was to evaluate the authors' results with the use of Leksell's gamma knife. METHODS AND RESULTS: In 1992-1994 48 patients with meningiomas were indicated for treatment with a gamma knife. The group comprised 12 men (25%) and 36 women (75%) aged 18-73 years (mean age 52.8 years which did not differ significantly in the two groups). In 19 patients (39.6%) one or more neurosurgical operations were carried out previously, in 4 patients (8.3%) fractionated radiotherapy. Karnofski's score, as an indicator of the general condition, varied between 30-90%, the mean value for the whole group being 71%. The calculated volume of the meningioma was between 0.7 and 25.8 cm3, the average being 7.4 cm3. Collateral oedema in the adjacent area of the tumour was found in 6 patients (12.5%). In 19 patients (39.6%) the tumour was at the base of the skull, in 29 patients (60.4%) at other sites. The radiosurgically administered dose was within the range of 6.5-24 Gy, on average 14,2 Gy, on the isodose on average 50.7% (range 40-75%). The dose below the maximum was within the range of 13-45 Gy), on average 28.3 Gy. Only in two patients fractionated administration of the dose was used. After a 6-month interval following operation 30 patients were examined. In 7 patients (23.3%) partial wrinkling of the meningioma occurred (range 6-18 months), Karnofski's score improved by 10% in 8 (26.6%) and deteriorated in 3 patients (10%). The neurodeficit improved in 7 (23.3%) and deteriorated in 4 patients (13.3%). Collateral oedema developed in 5 patients (16.6%) 5-7 months after operation, in about half the patients it was symptom free. During the follow up period 2 patients died (8 and 5 months following surgery): in one the cause of death was not associated with the basic disease, in the second patient (where radiotherapy was the third neurosurgical operation) the radiosurgical operation could not reverse tha fatal course of the disease. CONCLUSIONS: Radiosurgery of meningiomas is a safe therapeutic method with zero mortality, minimal surgical stress, a minimal rate of complications and a minimal morbidity. It is indicated in meningiomas and possibly their residues after subtotal neurosurgery up to a maximal volume of 30 cm3. It is primary treatment suitable in particular in old.patients, patients with a high per- and postoperative risk and in patients refusing open neurosurgery.

Adolescent↗
PubMed1995

[Use of the radiosurgery knife in the treatment of hypophyseal adenomas].

BACKGROUND. Surgery of pituitary adenomas did not produce quite satisfactory results. Therefore radiosurgery using Leksell's gamma knife has become the most widely used method which-with the contribution of MRI-meets the most important demands of aimed irradiation: a sufficiently high dose of radiation of the tumour and minimal radiation load of functionally important surrounding structures. The objective of the investigation was to assemble experience with this therapeutic method. METHODS AND RESULTS. During the period between October 1992 and September 1994 a total of 41 patients were treated: 16 men, 12-66 years old, mean age 40.8 years; 25 women age 16-76 years, mean age 50.2 years. Female:male ratio 1.5 : 1. In 30 patients (73.2%) a microsurgical operation had preceded, in 5 (12.2%) conventional fractionated radiotherapy and in 11 patients (26.9%) primary radiosurgery. As far as the type of pituitary adenoma is concerned, it conditioned acromegaly in 30, Cushing's syndrome in 3 or Nelson's syndrome in 1, or a prolactinoma was involved (in 2 patients). In five instances the adenoma was hormonally inactive. Its localization was most frequently intrasellar (36), less frequently parasellar (5). The range of administered doses varied as regards the maximum between 12.5 and 80 Gy, the average being 46.8 Gy, to the periphery of the adenoma a dose of 10-49 Gy was administered, on average 24.7 Gy using a 50-80% isodose. The time interval after treatment is relatively short for detailed analysis or evaluation. During current evaluation the authors did not observe in any of the patients progression of the disease, and in several patients diminution of the tumour was found. Karnofski's score seemed to improve. CONCLUSIONS. Radiosurgery, using Leksell's gamma knife, is after failure of conservative and microsurgical therapeutic possibilities suitable further treatment of pituitary adenoma. In indicated cases it may be the first choice. Postirradiation follow up indicates promising effects, for more detailed evaluation a several years' interval is necessary.

Adenoma↗
PubMed1995

[Fractionated stereotaxic radiotherapy with the Leksell gamma knife].

BACKGROUND: Stereotactic radiotherapy is treatment of a small or medium-sized intracranial focus, using a fractionated regime and the stereotactic method. It is carried out usually on linear accelerators. The objective of the present investigation was to test the possibility of stereotactic radiotherapy using Leksell's gamma knife and Leksell's stereotactic frame. METHODS AND RESULTS: During the period between April 1993 and November 1994 38 patients (16 women and 22 men aged 15-72 years) were indicated for stereotactic radiotherapy. The patients had the following diagnoses: adenoma of the epipharynx (1), low-grade gliomas (10), ependymoma (1), germinoma (1), meningioma (2), solitary metastases into the CNS (19), pinealomas (3) and chordoma (1). The volume of the tumour varied from 740 mm3 to 37,000 mm3. Stereotactic fractionated radiotherapy was carried out using a Leksell Gamma Knife, Electa Instrument AB, Sweden. For assessment of the total fractionated dose a linear quadratic model was used. Thus assessed value was further modified in relation to the volume and radiobiology of the tumour, critical structures surrounding the treated lesion and other factors. The total fractionated dose to the maximum varied from 20 Gy to 60 Gy and the total fractionated dose on the periphery of the tumour from 12 Gy to 30 Gy. With regard to the short time interval which has elapsed since treatment it is not yet possible to evaluate completely the achieved results; it will be possible to do so after a time interval of 1-5 years following the operation. The patients tolerated the 2-5 day fixation with a stereotactic Leksell frame very well and none of the patients developed complications. CONCLUSIONS: Fractionated stereotactic radiotherapy with Leksell's gamma knife, using Leksell's stereotactic frame, is a very accurate therapeutic method with a minimal radiation load of surrounding brain tissue. It requires a short hospitalization period and is associated with no or only minimal complications and improves the quality of patient's lives.

Adolescent↗
PubMed1995

Fractionated stereotactic radiotherapy with the Leksell Gamma Knife: feasibility study.

The main aim of this study was to check feasibility of stereotactic radiotherapy, which is routinely practised on linear accelerators, using a fixed Leksell stereotactic frame and a Leksell Gamma Knife. The study refers to the first experiences with 48 patients treated by a fractionated regimen (in 2-6 days). Isoeffect relationships calculations based on the linear-quadratic model and the levels of applied radiation doses, taking into account radiobiology of the tumour, tumour volume, critical structures surrounding the treated lesion and other factors are discussed. The procedure for quality control during the whole fractionated regimen is described. The study has shown that stereotactic radiotherapy with the Leksell Gamma Knife is feasible. However, only early effects can be discussed and there are still questions remaining which should be carefully studied: tolerance doses for critical structures at fractionation, definition of an 'ideal' fractionation regimen, and justification of the linear-quadratic model in the case of stereotactic radiotherapy.

Brain Neoplasms↗
PubMed1995

[Hemocoagulation and hemorheology in heart failure and the possible effects of glycosaminoglycans].

Chronic congestive heart failure is one of the risk groups of acquired hypercoagulant and hyperviscous state. In a group of patients with medium and severe cardiac failure the administration of sulodexide led to an increased activation of the fibrinolytic potential--a drop of PAI-1 and fibrinogen, to an increased activation of anticoagulatory potential--an increase of AT III and reduced plasma viscosity. Global coagulation and biochemical screening parameters were not affected by treatment. Administration of the preparation did not exert important undesirable effects and was well tolerated.

Aged↗
PubMed1995

[G-CSF (Neupogen Roche) in the treatment of patients with chronic aplastic anemia with severe neutropenia].

Aplastic anaemia (AA) of the chronic type with severe cytopenia is very frequently a difficult therapeutic problem. Patients with granulocyte values below 0.5 G/l are threatened by infections, incl. sepsis possibly with a fatal outcome. If the pool of stem cells for granulocytes is not completely exhausted and can respond to growth factors, these patients can be treated either chronically and/or in risk situations (e.g. injury, surgery) with preparations of the type of a recombinant, granulocyte colony stimulating factor (rhG-CSF), or granulocyte and monocyte colony stimulating factor (rhGM-CSF). The authors present a review of diagnostic and therapeutic algorithms in patients with the AA syndrome and summarize their own experience with the preparation Neupogen Roche (rhG-CSF).

Anemia, Aplastic↗