Biomedical subjects

J Polák

Publications and source records attributed to J Polák.

At least 19 recordsLinked to original sources

PubMed1995

Multiple forms of cathepsin B in human lung cancer.

In this study we have examined, by means of isoelectric focusing (IEF) in native polyacrylamide gel and contact-print fluorescence zymography, whether human lung carcinomas and the lung parenchyma contain different pools of multiple charge forms of the cysteine proteinase cathepsin B. The isoelectric point (pI) patterns of cathepsin B from lung carcinoma and matched lung were similar, particularly with regard to 2 major intermediate acidic enzyme pI forms designated as I and II (pIapp of 5.10 and 4.93 in tumors, and 5.11 and 4.94 in lungs, respectively). The slightly acidic cathepsin B pI forms (pIapp 5.47-5.19) in squamous-cell lung carcinoma (SQCLC) were significantly more numerous than such enzyme pI forms in lungs. The numbers of the highly acidic cathepsin B pI forms (pIapp 4.82-4.33) were significantly higher in SQCLC and lung adenocarcinoma (ACL) than in matched lung. The activity distribution percentage in the set of highly acidic cathepsin B pI forms was significantly higher in SQCLC and ACL than in matched lung. We also observed that cathepsin B from SQCLC and matched lung was fully recoverable by IEF from inhibition by leupeptin. Using the cysteine-proteinase-specific inactivator E-64, we revealed by IEF that some cathepsin B isoforms (charge forms) from SQCLC were more resistant to inactivation by this compound than the corresponding enzyme isoforms from lungs. After IEF, the enzyme isoforms apparently lost their resistance to E-64. Our results indicate that the pool of multiple charge forms of cathepsin B in SQCLC and ACL is different from that in the lung, and also that there may be an increased level of loose complexes between cathepsin B and some proteins or polypeptides in SQCLC compared to the lung.

Adenocarcinoma↗

PubMed1994

Extracellular volume fraction and diffusion characteristics during progressive ischemia and terminal anoxia in the spinal cord of the rat.

Extracellular space (ECS) volume fraction (alpha), ECS tortuosity (lambda), and nonspecific uptake (k'), three parameters affecting the diffusion of substances in nervous tissue, were studied during ischemia and anoxia in the rat spinal cord gray matter in vivo. Progressive ischemia evoked by exsanguination, as well as anoxia evoked by respiratory or cardiac arrest, produced prominent extracellular K+ and pH changes closely related to a decrease in blood pressure and amplitude of field potentials. With use of ion-selective microelectrodes, the changes in the diffusion parameters were measured by quantitative analysis of concentration-time profiles of tetramethylammonium (TMA+) applied by iontophoresis concomitantly with ionic shifts. Under normoxic conditions (in rats with blood pressure of 80-110 mm Hg) diffusion parameters in the dorsal horn gray matter at depth 500-900 microns were as follows: alpha = 0.20 +/- 0.019, lambda = 1.62 +/- 0.12, k' = 4.6 +/- 2.5 x 10(-3) s-1 (mean +/- SD, n = 39). Extracellular K+, pH, and diffusion properties gradually changed during progressive ischemia. As the blood pressure fell to 50-60 mm Hg and field potential amplitude to 20-60%, K+ rose to 6-12 mM, pHe fell by approximately 0.05-0.1 pH unit, and volume fraction of the ECS significantly decreased, to alpha = 0.16 +/- 0.019 (n = 22). Even though the tortuosity remained virtually constant, the nonspecific uptake significantly decreased to k' = 3.4 +/- 1.8 x 10(-3) s-1. As the blood pressure fell to 20-30 mm Hg and field potential amplitude to 0-6%, K+ rose to 60-70 mM, pHe fell by approximately 0.6-0.8 pH unit, and all three diffusion parameters significantly changed. The ECS volume fraction decreased to alpha = 0.05 +/- 0.021, tortuosity increased to lambda = 2.00 +/- 0.24, and TMA+ uptake decreased to k' = 1.5 +/- 1.6 x 10(-3) s-1 (n = 12). No further increase in extracellular K+ or changes in the alpha were found during and up to 120 min after the death of the animal. However, there was a further significant increase in lambda = 2.20 +/- 0.14 and decrease in k' = 0.4 +/- 0.3 x 10(-3) s-1 (n = 24). The acid shift reached its maximum level at approximately 5-10 min after respiratory arrest and then the pHe gradually increased by approximately 0.2 unit. Full recovery to "normoxic" diffusion parameters was achieved after reinjection of the blood or after an injection of noradrenaline during severe ischemia, if this resulted in a rise in blood pressure above 80 mm Hg and a decrease in extracellular K+ below 12 mM.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1993

[The Bayesian statistical theory in the diagnosis of malignant and non-malignant diseases of the lung, pleura and mediastinum].

The Bayesian algorithm was used to assess the probable diagnosis in 1262 patients with a recently diagnosed finding on X-rays of the chest and the results were compared with the final diagnosis. The patients were with regard to the X-ray picture divided into 9 groups: hilar, solitary, multiple, segmental, non-segmental, cavity, diffuse, pleural and mediastinal lesions. Using the Bayesian algorithm, commonly accessible factors were processed: age, sex, case-history, cigarette smoking, red cell sedimentation rate, number of leucocytes and diameter of solitary parenchymatous lesions and the impact of these factors for assessment of probability of a malignant or non-malignant lesion was evaluated. The reliability in different X-ray lesions was within the range of 84.2% to 92.4%. The authors evaluated also tests of sensitivity, specificity, the reliability of forecast of a positive and negative result, which confirmed the differences in the different groups which showed evaluated. Analysis of the results, provided evidence that the Bayesian algorithm is a promising objective method for the forecast of a malignant or non-malignant diagnosis in patients with a newly diagnosed X-ray finding of the chest.

Adolescent↗

PubMed1992

Model of distribution of anticancer agents transplanted into the brain tissue using the random walk method.

A Monte-Carlo approach to analysis of dispersion in the tissue of a locally administered drug is presented. The distribution of a drug in the tissue is simulated as a distribution of randomly walking particles. The approach is demonstrated on a simple situation for which both experimental results and an analytical solution are known. The approach can be used in situations, where common numeric methods are difficult to use, especially for analyses of drug transport in an inhomogeneous space, and problems with complex boundary conditions, e.g. in analyses of dispersion of anticancer agents locally applied into tumours.

Animals↗

PubMed1991

[Environmental monitoring and biological monitoring of young people exposed to nonoccupational levels of formaldehyde, toluene and other hydrocarbons].

During the period of 1983-1985, in two of apprentice schools of P. town the health disorders were investigated in the total of 82 apprentices 15-18 years old from the environment with elevated concentrations of formaldehyde and toluene. The study was contrasted with a control total of 42 apprentices. Cytogenetical examination has been performed, and selected immunological parameters in both blood serum and saliva have been assessed with red and white blood cells counts including differential formula of white blood cells. In addition, the atmospheric toxicity of formaldehyde and vapours of organic solvents (toluene, xylene, varnish naphtha) was measured. A single biological exposure test has been performed for the detection toluene. Statistically significant were differences in occurrence of cell chromosomal aberrations between the group of long term formaldehyde and toluene exposure (averagely 3.53% ABB) and controls (2.21% ABB) as obtained in 1983 and 1984, and so were differences between the long term-to-toluene exposed group (3.30% ABB) and the above mentioned control group as obtained in 1984. No similar results were stated between the long term-to-formaldehyde exposed (3.07% ABB) and control (2.55% ABB) groups in 1985. The main evidence consisted in finding the genotoxical/clastogenic effect of observed agents associated with mainly chromosomal abnormalities of chromatide type. It outflowed from the determination of selected serum proteins (Ig and acute phase proteins) and salivary lysozyme that the group under the combined influence of formaldehyde and toluene showed significantly lower IgG and higher alpha-1-antitrypsin (A1AT). The group at risk of toluene was characteristical in elevated concentrations of alpha-2-macroglobulin (A2M) and A1AT. Most pronounced changes in first year had been revealed through the evaluation of the influence of the duration at risk (significant decrease in IgA and prealbumin, and the increase in A2M and A1AT). The infectious disease as experienced 2 month prior the collection resulted in a significant decrease of IgM, A2M and A1AT in risky groups in individuals with infection in anamnesis. Salivary lysozyme concentration of apprentice environmentally exposed to formaldehyde in the noon showed the decrease, whereas its increase occurred in controls with the difference on 5% significancy level. Blood count assessements showed no significant differences between the investigated values as well as any were assessed between the incidence of health disorders of apprentices and their correspondance to the given group.

Adolescent↗

PubMed1990

[Bronchogenic carcinoma in women].

A total of 440 women with morphologically tested primary bronchogenic carcinoma were hospitalized in 1961-1987. The patients' average age was 57 years, 22% persons were under 50 years. In 32% women carcinoma was found accidentally in the asymptomatic stage of the illness, 4% women had subjective complaints which they considered insignificant, however, subjective complaints in 64% patients helped to diagnose it. The most frequent complaints were temperature, breathlessness, chest pain and loss of weight. In 2% women, the first sign was hemoptysis found most frequently as an isolated symptom. The history of 9.5% patients showed pulmonary TB, in 27% women bronchogenic carcinoma was first regarded as pulmonary TB and treated with anti-tuberculotics. The family history of 32% patients showed malignant diseases, most frequently gastric carcinoma, while bronchogenic carcinoma was found in 5.7%, of family members. The group consisted of 46% smokers and 54% non-smokers. The women smokers had smoked for 29 years on average, had smoked 205 thousand cigarettes on average, the average daily amount was 20 cigarettes. Regardless of their smoking habits, the most frequent histological type was found to be adenocarcinoma in 47% cases, with the squamous-cell type prevailing in the smokers (37%), and adenocarcinoma in non-smokers (59%). 36% of the patients underwent surgery, the most frequent contraindication for surgery were generalization of the process and lymph node metastases. Lobectomy was the most common operation performed (62%). 5 patients died within the first post-operative month.

Adult↗

PubMed1990

[Vascular tumors of the lungs].

A series of nine vascular tumors of the lungs, five of them being benign hemangiomas, three hemangiosarcomas and one hemangiopericytoma is presented. In five patients the disease was detected on the basis of subjective complaints which indicated necessary hospitalization, in the other four patients the tumours were revealed by chance during preventive X-ray examination or X-ray examination for other causes. These patients were admitted to hospital for progression of lung changes. Five of the patients underwent surgery, lobectomy, was made in two cases, the other patients were treated by segmental, V-shape or atypical lung resection. Patients with benign hemangiomas manifested the best prognosis even in those where surgery was not possible. In cases of hemangiosarcoma or hemangiopericytoma the outlook is exceptionally serious even in primary forms. In the preoperation diagnostics of arteriovenous hemangiomas the tomographic examination and lung angiography represents an important help, in the other vascular tumours it is particularly CT and lung biopsy.

Adult↗

PubMed1989

[Percutaneous transthoracic aspiration biopsy: the reliability of cytological diagnosis of intrathoracic tumors].

The authors evaluated percutaneous aspiration biopsies of intrathoracic lesions in 348 patients where the obtained cytological results were compared with the histological finding from resections or post-mortem preparations. In 274 patients malignant and in 74 benign disease was confirmed. In the differentiation of malignant and benign disease the sensitivity of cytology was 84.3%, the specificity 91.9% and the accuracy 85.9%. The type of bronchogenic carcinoma was correctly diagnosed by cytological examination in 69.5%, in squamous cell carcinoma in 76.8%, in small-cell carcinoma in 80% and in adenocarcinoma in 59.1%. The same cytological finding as in the primary tumour was recorded in 73.5% of the patients with metastases in the lungs. Less favourable results as regards assessment of the type of tumour were obtained in other tumours, in particular in lymphogranulomas and non-Hodgkin lymphomas. In 25% it proved possible to assess by cytological examination the type of benign lung tumour.

Biopsy, Needle↗

PubMed1989

[Benign tumors of the lungs and bronchi].

Results of a retrospective study from the years 1961 to 1986 have been presented based on hospitalization of 292 patients with benign tumours of the lungs and bronchi verified by histology. The prevailing tumours in the cohort were chondrohamartomas (62.0%) and carcinoids (21.9%). The tumours were localized more frequently inside the parenchyma (75.7%) than inside the bronchi (24.3%). The patients were men in 59.9% and women in 40.1%, the mean age during hospitalization being 48.8 years. In 60.6% of the patients the tumours were detected during an accidental radiographic examination, the tumour increased in size over several years of observation in 22.6% of the patients. A total of 280 patients (95.5%) were surgically treated, the tumour was removed in the bronchoscopic way in nine cases, two patients could not be operated on for advanced processes and one patient refused the operation. In 83.2% of the patients the surgical intervention was smaller than lobectomy, larger interventions prevailed in endobronchial localization making 54% on the whole, bronchial carcinoids being 71% of these.

Bronchial Neoplasms↗

PubMed1989

Percutaneous thin needle biopsy of malignant and nonmalignant thoracic lesions.

An analysis of 1,454 percutaneous thin needle biopsies (PTNB) performed in 1,061 patients in the years 1976-1987 disclosed the sensitivity for the detection of malignancy 93.7%, specificity 95.8%, and accuracy 93.9%. The most commonly encountered indication for PTNB was a solitary lung lesion (56% of 1,061 patients), with a rate of true positive cytologic findings 93.4% of patients with proved malignant tumours. Indications for PTNB included pulmonary opacities of or without recognizable segmental distribution, enlargement of mediastinum or hilus, lesions of the pleura or chest wall, and cavitary lesions, with results not significantly worse than in circumscribed peripheral lesions. Pneumothorax occurred in 18%, hemoptysis in 1.9%, other minor complications very rarely. PTNB appears to be a safe, reliable, and accurate technique for diagnosing chest lesions with various types of roentgenographic image.

Adolescent↗

PubMed1988