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Biomedical subjects

K Lapis

Publications and source records attributed to K Lapis.

At least 199 records · Page 11Linked to original sources
PubMed1981

Growth of human colorectal tumor xenografts in immunosuppressed mice reconstituted with normal cells.

The growth of human colorectal tumor xenograft lines was studied in immunosuppressed mice after reconstitution with sensitized and nonsensitized macrophages, thymocytes and splenocytes obtained from normal mice. Intravenously injected macrophages caused temporary inhibition of tumor growth. This effect needed intact cells and was independent from the presence of the spleen. The weight of spleen increased in normal mice sensitized with xenograft tumor, and the sensitized splenocytes injected into tumor-bearing immunosuppressed mice caused substantial tumor-growth delay.

Animals↗
PubMed1981

Morphologic and clinico-pathologic features of thymus tumours.

A total of 37 thymic tumours was studied out of which 29 proved to be of epithelial origin. Thymomas may be accompanied by a minimal, marked or an overwhelming lymphoid reaction, pointing to the degree of the cellular defensive mechanism. According to the findings, two main types of thymoma with minimal lymphoid reaction (light and dark cell types) can be distinguished. All the 7 light cell thymomas with minimal lymphoid reaction proved to be malignant in their clinical course. Thymomas of light cell origin with marked lymphoid reaction may be clinically benign or malignant. Thymomas with overwhelming lymphoid reaction were clinically benign. The clinical behavior of the dark cell thymomas was benign. The dark cell thymomas could be divided into subgroups with solid, lacunar and spindle cell forms. Three non-Hodgkin type thymic lymphomas were observed. The T cell origin of one of these tumours was demonstrated immunologically. All the five cases of Hodgkin type thymic lymphoma were morphologically identical to the modular sclerotic form of lymphogranulomatosis.

Adolescent↗
PubMed1981

Ultrastructure of human colorectal tumour xenografts maintained serially in immunosuppressed mice.

Five colorectal human tumour xenograft lines maintained by serial transplantation in immunosuppressed mice were studied by light and electron microscopy. Three had adenomatous while two had a mixed (adenomatous and mucinous) structure in the surgical specimens. After xenotransplantation in the mixed tumours the mucinous areas became dominant. Beside this there were no striking differences in the fine structure of the primarily implanted tumour compared with serially transplanted ones or between the different passages. The cells in adenomatous tumours formed acini with well-developed junctional complexes while the mucinous areas of mixed tumours were composed of single or loosely attached cells. In the former ones the cells had irregular microvilli on the apical surface and were separated from the stroma by a continuous basal lamina missing. The partially preserved functional activity was indicated by small vesicles in adenomatous, and mucin-droplets in mucinous tumours, showing intimate relationship with the rough endoplasmic reticulum and well-developed Golgi region. Some cells had features characteristic of both adenomatous and mucinous tumours. The ultrastructure of the studied tumours called attention to the possibility that malignant transformation may occur at different levels of cell differentiation.

Adenocarcinoma↗
PubMed1981

Cytochemical characterization of hepatitis B virus infected liver cells in chronic liver diseases.

The cytochemical characteristics of the hepatitis B virus (HBV) components, the nuclei and cytoplasm of the infected cells were studied in liver needle biopsy material obtained from patients suffering from serologically HBsAg positive chronic hepatitis. The HBV surface and core components were found to be more resistant to proteolytic enzymes and phospholipase than the other cellular components, and only combined digestion was effective. With preferential RNP and specific DNP staining the accumulation of granules 10-20 nm and 20-40 nm in diameter could be observed in the liver cell nuclei. The cytochemical-morphological polymorphism of the latter was well detectable. Part of the granules corresponded to accumulated perichromatin granules. It is assumed that the groups of granules 20-40 nm in diameter, showing a varying density on DNP staining, similar to the chromatin on RNP staining, and not surrounded by a peripheral area represents one of the forms of appearance of the HB virus core component.

Cell Nucleus↗
PubMed1981

Effect of macrophages on the growth of syn- and xenogeneic tumors.

Human colorectal tumors transplanted in immune-suppressed mice (xenogeneic system) and metastasizing Lewis lung carcinoma (syngeneic system) were used to study the effect of macrophages on tumor progression. Carrageenan modifying the structure of macrophage cell coat and damaging the membrane of lysosomes led to severe disturbances in macrophage functions. The inhibition of macrophage activity by Carrageenan produced an enhancement in tumor take in both systems. In another set of experiments peritoneal macrophages were injected into tumor-bearing mice. In both systems the non-stimulated macrophages given i.v., produced a delay in tumor growth. These results indicated that the activity of macrophages influences markedly the tumor progression--even in hosts with damaged T cell population.

Animals↗
PubMed1981

Effect of a new bifunctional nitrosoureido derivative on human colorectal tumor xenografts.

The tumor inhibiting effect of a newly developed bifunctional nitrosoureido derivative (GYKI-13324) was studied on human colorectal tumor xenograft lines. Given orally in single or multiple daily doses, GYKI-13324 produced long-term or total regression of adenomatous, but only marginal growth delay of mucinous tumors. GYKI-13324, with slightly lower toxicity than that of BCNU, seems to be a candidate in the clinical management of colorectal tumors.

Animals↗
PubMed1980

Effect of combined surgical and chemotherapeutic treatment of Lewis lung carcinoma.

The effect of combined surgical and chemotherapeutic treatment on Lewis lung carcinoma was studied. The i.m. implanted primary tumor was removed on the 10th day after transplantation, and the survival of mice was registered. Cyclophosphamide proved to be the most effective among the drugs studied (Cyclophosphamide, 5-FU, DBD, CCNU, Adriamycin, Vincristin, Hexyldeoxyuridine). Using different schedules (pre- and/or post-operative treatment) the pre- and post-operative drug administration was the most advantageous. Combined therapy showed always better effect than monotherapy.

Animals↗
PubMed1980

ESR investigation of paraffin-embedded ocular melanomas.

Ocular melanomas embedded in paraffin wax for histological examination have been studied by electron spin resonance (ESR) spectroscopy. A free-radical signal was detected at the g = 2.003 section of the spectrum. The amplitude of this signal was correlated with the number of melanin granules in microscopical slides made from the tumour. This positive correlation can make ESR spectroscopy suitable for estimating the melanin content in the embedded melanoma blocks. Additional paramagnetic signals can also be detected. The clarification of their significance needs, however, further ESR measurements.

Electron Spin Resonance Spectroscopy↗
PubMed1980

Scanning electron microscopic study of oral leukoplakia.

Biopsy specimens of buccal mucosa from six oral leukoplakia patients and one specimen of normal buccal mucosa were studied by scanning electron microscopy. The results showed: (1) There was a difference between the surfaces of normal and leukoplakic epithelial cells. (2) The appearance varied with the clinical type of leukoplakia: in leukoplakia verrucosa, epithelial cells appeared keratinized; in leukoplakia erosiva, epithelial cells were dissociated. (3) Histologically, dysplastic erosive leukoplakia was characterized by an atypical arrangement of superficial cytoplasmic projections of epithelial cells.

Adult↗
PubMed1980

Chemotherapeutic sensitivity of human colorectal tumor xenografts.

Studies were made of the therapeutic response of six human colorectal tumor lines serially transplanted in immunosuppressed mice. The tumors with adenomatous structure showed greater sensitivity against different cytotoxic agents than the gelatinous ones. Among the drugs, 5-FU, BCNU and MeCCNU proved to be the most effective, producing not only temporary but long-term regressions. BCNU had its maximal effect at a single, oral administration. 5-FU sensitive and insensitive lines showed an equal uptake and incorporation of radiolabeled 5-FU. Both the take rate and the growth of nontreated and treated tumors in the same host revealed the influence of host-defence mechanisms on tumor progression.

Animals↗
PubMed1980

New type bifunctional nitrosoureido derivatives with cytostatic activity.

Several bifunctional nitrosoureido sugar alcohol derivatives were synthesized at the Institute for Drug Research in Budapest. For detailed studies two D,L-threitol derivatives have been selected (GYKI 13 324, GYKI 13 485). These compounds were less toxic and more effective than BCNU, the calculated therapeutic index values in a broad scale of transplantable, induced and heterotransplanted tumours were found to be more advantageous than with the referent compound. Both GYKI 13 324 and GYKI 13 485 exert their curative effect when given orally even in leukaemia types of tumours. Their effect on the blood picture of rats is moderate and of short duration.

Animals↗
PubMed1980

Morphological and biochemical study of the hepatoprotective effect of AICA-phosphate.

The hepatoprotective effect and the possible mechanism of action of AICA-phosphate (AIP) were studied. Both the morphological and biochemical data proved the protective i.e. the connective tissue reducing effect of AIP in cirrhotic rat liver. Labelled AIP incorporated very intensively into microsomal RNA, suggesting that the compound may take part in the de novo purine synthesis. The increased rate of protein synthesis can be the consequence of the incorporation into RNA, promoting the regenerative processes in injured cells.

Aminoimidazole Carboxamide↗
PubMed1980

[Determination of the copper content of liver tissue from paraffin-imbedded samples by electron spin resonance spectroscopy].

The Electron Spin Resonance spectrum of human liver specimens embedded in paraffin was investigated. An easily registrable mark could be seen in the g 2.05 range of the spectrum. A correlation was detected between the amplitude of this mark of the embedded specimens and the copper content of them measured by a flame ionic-absorptive technique. Authors assume that ESR-spectroscopy is a useful tool for the estimation of the copper content of a specimen, it does interfere with the following histological processing of it. Sources of errors are shortly discussed.

Copper↗
PubMed1980

[Electron spin resonance study of melanin in paraffin-imbedded ocular melanoma specimens].

The Electron Spin Resonance (ESP) spectrum of ocular melanomas embedded in paraffin was studied. In the g approximately 2.003 range of the spectrum a mark of a free radical was detected. The correlation between the amplitude of the latter and the number of melanin granules in sections was studied. Considering the positive correlation revealed, authors believe, that ESR spectroscopy is a suitable tool for detecting melanin in paraffin embedded specimens. As an effect of oxidation or reduction melanin turns pale, however this phenomenon is not in tight connection with the decrease of the amplitude of the free-radical-mark. Very seldom different types of spectrum (peroxide, cupric ion) may appear, so it is reasonable to study large number of specimens.

Electron Spin Resonance Spectroscopy↗