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Biomedical subjects

J Polański

Publications and source records attributed to J Polański.

At least 19 recordsLinked to original sources
PubMed2001

Liver regeneration after anatomical resections.

BACKGROUND: The authors present the results of investigation of liver regeneration after partial parenchyma resection. MATERIAL AND METHODS: 20 patients (16 females, 4 male) aged 31-67 years were operated on because of metastatic colon cancer (7 cases), cavernous hemangioma (6 cases), hepatocellular carcinoma (1), alveococcosis (2), metastases of malignant melanoma (1), gall bladder carcinoma (1), FNH (1) and mucous cystadenocarcinoma (1). The resection according to anatomical segments by Couinaud were performed. Spiral CTs including liver volumetry were taken before and 30 days after the operation. on the 7-th day after the surgery, liver biopsy was performed and the material was examined under light and electron microscope. RESULTS: There was no postoperative mortality. We observed transient elevation of transaminases, bilirubin levels and decrease of albumin level. Control spiral CT revealed increased liver volume in 15 cases (75 percent). In 16 cases (80 percent), electron microscopy investigations showed regeneration of the liver (mitotic figures). CONCLUSIONS: Our material shows that hyperplasia as well as blood vessel and bile duct neogenesis play a very important role in liver regeneration process.

Adult↗
PubMed2000

The non-grid technique for modeling 3D QSAR using self-organizing neural network (SOM) and PLS analysis: application to steroids and colchicinoids.

A novel method for modeling 3D QSAR has been developed. The method involves a multiple training of a series of self-organizing networks (SOM). The obtained networks have been used for processing the data of one reference molecule. A scheme for the analysis of such data with the PLS analysis has been proposed and tested using the steroids data with corticosteroid binding globulin (CBG) affinity. The predictivity of the CBG models measured with the SDEP parameter is among the best one reported. Although 3-D QSAR models for colchicinoid series is far less predictive, it allows for a discussion on the relative influence of the structural motifs of these compounds.

Binding Sites↗
PubMed2000

Self-organizing neural network for modeling 3D QSAR of colchicinoids.

A novel scheme for modeling 3D QSAR has been developed. A method involving multiple self-organizing neural network adjusted to be analyzed by the PLS (partial least squares) analysis was used to model 3D QSAR of the selected colchicinoids. The model obtained allows the identification of some structural determinants of the biological activity of compounds.

Colchicine↗
PubMed2000

Self-organizing neural networks for modeling 3D QSAR--a comparative study.

Different architectures of self-organizing neural networks (SOM) have been used for modeling 3D QSAR. The atomic coordinates and partial atomic charges were used as input signals. In particular, the steroids complexing corticosteroid binding globulin (CBG) that are used as a benchmark measuring the performance of drug design methods have been applied to compare between individual methods. The sensitivity of the different architectures for changes of the alignments of the molecules within series, as well as the possibility for alignments based on the molecular inertial axes have been tested.

Drug Design↗
PubMed2000

A search for new glucophores by isosteric replacement of carboxylic function.

We used arylsulfonylalkanoic acids as parent structures for designing new potential sweeteners. The Kohonen maps of the molecular electrostatic potential of the possible bioisosteric replacements of carboxylic function have been simulated and used for the selection of the potential synthetic targets which are now under synthesis.

Drug Design↗
PubMed1998

Aldehyde dehydrogenase isoenzymes in tumours--assay with possible prognostic value for oxazaphosphorine chemotherapy.

A novel fluorimetric assay, allowing independent measurement of the activities of two principal cytosolic forms of human aldehyde dehydrogenase, ALDH-1 and ALDH-3 (known as a tumour-associated ALDH) was applied to estimate the activities of these isoenzymes in human liver and thyroid tumours. The assay is based on two artificial substrates, 6-methoxy-2-naphthaldehyde (MONAL-62) and 7-methoxy-1-naphthaldehyde (MONAL-71), exhibiting excellent substrate properties toward various forms of human ALDH (see Wierzchowski et al., 1997, Anal. Biochem. 245, 69-78). We have found significant differences in ALDH activities between malignant and non-malignant tissue fragments, particularly in cancerous livers. Out of 16 tumours examined, only 4 exhibited ALDH-1 activities comparable to that found in the tumour-free tissue (0.5-2.5 U/g), while in the remaining 12 this activity was at least 10-fold lower. The ALDH-3 activity was detectable in about 40% of both tumour and tumour-free liver samples (maximum value 1.5 U/g). Comparison of 13 pathological thyroid fragments revealed ALDH activities in the range of 0.02 to 0.35 U/g, with two malignant samples showing activities of 0.27 and 0.18 U/g. Both substrate specificity and kinetic behaviour of the thyroid ALDH (Km values for the fluorogenic naphthaldehydes as well as propanal inhibition profile) were similar to those of the purified ALDH-1. In 5 thyroid samples traces of ALDH-3 activity was detected, using MONAL-62 and NADP+ as substrates (maximum value 0.04 U/g). Possible prognostic value of the foregoing measurements for cyclophosphamide chemotherapy is discussed.

Aldehyde Dehydrogenase↗
PubMed1991

[A case of B-cell lymphoma imitating bronchocentric granulomatosis].

A case is presented of primary, pulmonary B-cell lymphoma imitating bronchocentric granulomatosis. The initial manifestations were of multiple, pulmonary nodules, without intra- and extrathoracic lymph node, bone marrow and spleen involvement. Despite the initial removal of the affected pulmonary tissue the progression of the disease led to additional immunohistochemical evaluation of the resected tissue and final diagnosis. The authors also carry out a differential diagnosis of the reported changes.

Adult↗