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Biomedical subjects

K Lapis

Publications and source records attributed to K Lapis.

At least 145 records · Page 8Linked to original sources
PubMed1985

Hepatoprotective effects of prostacyclins on CCl4-induced liver injury in rats.

Certain biochemical parameters of acute liver injury induced by carbon tetrachloride were investigated in rats treated with prostacyclin (PGI2) and two of its derivatives. Serum glutamate oxalacetate transaminase elevation and both triglyceride accumulation and reduction of glycogen content in liver were significantly suppressed by PGI2, 7-oxo-PGI2, and 20-methyl-13,14-didehydro-2,4-m-interphenylene-PGI2 48 hr after the injury. Prostacyclins partially restored some of the parameters of injury even in doses of 10 micrograms/kg ip. When the compounds were given 24 hr after CCl4 intoxication, much more pronounced protection was observed than in the case of treatments 1 hr before administration of the hepatotoxin. Thus, all tested prostacyclins exerted significant protective effects on acute liver damage which is obtained mainly in the second phase of the injury.

Animals↗
PubMed1985

Increased SCE inducibility by low doses of methylcholanthrene in lymphocytes obtained from patients with Down's disease.

The inducibility of sister-chromatid exchanges (SCEs) following 3-methylcholanthrene (MC) treatment of normal human peripheral blood lymphocytes and of in vitro cultured normal human embryo fibroblasts, as well as peripheral blood lymphocytes of patients with Down's disease and of fibroblasts of an embryo with trisomy 21 has been investigated. 10(-6) M MC treatment increased the frequency of SCEs by 2.5 in the case of Down lymphocytes when compared to the healthy control. The fibroblasts with trisomy 21, however, did not show an increased sensitivity to MC treatment when compared with normal fibroblasts, expressed in the number of SCEs per nucleus found in the cells.

Dose-Response Relationship, Drug↗
PubMed1985

What's new in macrophage-tumor cell interaction?

Macrophages--alone or interacting with other host defense elements--can modify the tumor growth, which usually means a process ending with tumor-cell killing, but in some instances may promote tumor progression. The knowledge on the actual capacity of host extra- and/or intratumoral macrophages to be activated by different kinds of biological modifiers or other effector cells, is necessary in order to design effective immun-manipulation in cancer patients. Progression of malignant tumors can be considered as the outcome of innumerable interactions between tumor cells and host cells with a clear indication on the failure of host defense. Host defense against tumors represents a complex series of interrelated specific and non-specific reactions of different cell types including macrophages. There is little doubt that macrophages--at least in vitro--can effectively destroy tumor cells by cytolytic mechanism, although in few instances their supportive effect on tumor growth is also documented. All of these events require the activation of macrophages.

Animals↗
PubMed1985

Characteristics and chemotherapeutic sensitivity of a human testicular cancer grown in artificially immunosuppressed mice.

Seven human testicular tumors were transplanted into artificially immunosuppressed mice. Two of them grew progressively (TT2 and TT6) and a serially transplantable line was developed from TT2. The xenografts maintained only the embryonal carcinoma components of originally mixed (embryonal cell carcinoma and choriocarcinoma) donor tumor. Although the histology did not change remarkably with passages, the xenografts lost their capacity to express human choriogonadotropin and alpha-fetoprotein. The latency period shortened, the growth rate remained similar with subsequent transplantations. The tumor cells of the TT2 line presented the human character according to chromosome analysis and were built up of two subsets of cells with a different DNA index estimated by flow cytometry. The embryonal cell carcinoma line was highly sensitive to CY and cisDDP. PVB combination was also effective, although the tumor growth inhibition proved to be only temporary.

Adult↗
PubMed1985

Fibronectin in differential diagnosis of primary hepatomas and carcinoma metastases in the liver.

Human liver specimens with primary hepatocellular and cholangiocellular carcinoma and liver metastases of cancers from different organs were studied for the distribution of fibronectin (Fn) by immunoperoxidase staining. With the exception of an undifferentiated type, all six well and moderately differentiated primary hepatocellular carcinomas contained Fn in the intercellular spaces and on the surface of certain cells of the tumour parenchyma, while in the case of three cholangiocarcinomas Fn could only be detected in the loose reactive connective tissue stroma. No Fn was observed around individual tumour cells in any of eleven carcinoma metastases in the liver. These findings indicate that hepatocellular but not cholangiocellular carcinomas synthesize Fn, while carcinoma metastases from other organs do not contain Fn in their parenchyma only in the reactive stroma. In this way the presence of Fn in the pericellular matrix of the tumour parenchyma may help to distinguish primary hepatomas from metastases. Metastases with strong fibroplastic character and pericellular fibrosis may, however, imitate Fn production.

Adenoma, Bile Duct↗
PubMed1985

Comparative study on Lewis lung tumor lines with 'low' and 'high' metastatic capacity. I. Growth rate, morphology and resistance to host defence.

A highly metastatic variant (LLT-HH) of liver metastasizing Lewis lung tumor (LLT) has been selected. Comparative studies were made on proliferation rate, morphological characteristics and host cell interaction of these two lines. Increased metastasis formation seemed to result from the selection of cells with increased resistance to nonspecific host effector cells.

Animals↗
PubMed1985

The effect of TP-5 and its analogs on skin grafts in mice.

The immunostimulatory action of oligopeptides RGH-0205 (Arg-Lys-Asp), RGH-0206 (Arg-Lys-Asp-Val) and TP-5 (Arg-Lys-Asp-Val-Try) was measured using the B10LP to C57BL skin graft system and the determination of splenic T cell ratio. While thymectomy increased the period between skin grafting and rejection, each of the oligopeptides increased the number of splenic T cells and in some extent restored the rejection capacity of thymectomised C57Bl mice, presumably by restoration of thymic hormone function.

Adjuvants, Immunologic↗
PubMed1985

Drug action and chromatin structure. I. Adriamycin binding to core particle of nucleosomes and subsequent enhanced DNA fragmentation induced by micrococcal nuclease.

The relevance of the subunit structure of chromatin to the mode of action of Adriamycin in Novikoff hepatoma had been investigated. To elucidate whether drug binding takes place at random along the chromatin fiber or not Novikoff hepatoma nuclei treated with Adriamycin in vivo were digested with Micrococcal nuclease and were subsequently separated into three fractions, S1, S2 and P2. In these chromatin fraction Adriamycin and the DNA content was determined. DNA were isolated from the above fractions and were analyzed by polyacrylamide gel electrophoresis, furthermore the S2 fraction was sedimented on sucrose density gradient. The results indicate that binding of Adriamycin takes place preferentially on the core particle inducing structural alterations. Adriamycin binding not only enhanced DNA nuclease digestion but altered the size of the fragments.

Animals↗
PubMed1985

The physico-chemical properties of tumor cells with different metastatic potential.

Authors investigated the total and surface sialic-acid content and elpho mobility of Lewis lung lines with low (LLT-parent) and high (LLT-HH selected) metastatic capacity. They pointed out, that the total and surface sialic-acid content of LLT-HH primary tumor cells is higher than in the cells of the LLT line. Despite the increase of sialic-acid on the cell surface, the electrophoretic mobility of the cells was unchangeable. The changes in sialic acid content are the markers of the metastasizing cells, but not of the highly metastatic cell lines.

Animals↗
PubMed1984

Renal cell carcinoma--xenotransplantation into immuno-suppressed mice.

21 human renal cell carcinomas (RCC) were xenotransplanted into artificially immunosuppressed mice. 4 tumors grew successfully retaining some characteristics of the primary tumors (according to morphology and karyotype analysis), but losing metastatic capacity. One of the serially transplantable tumors (HT 40) with hyperdiploid cellular DNA content and estrogen receptor positivity failed to respond to the single maximally tolerated dose of several cytotoxic agents.

Adenocarcinoma↗
PubMed1984

Potentiation of the antitumor action of 5-fluorouracil with 5-ethyl-2'-deoxyuridine in human colorectal tumor xenografts.

The tumor growth inhibitory effect of 5-ethyl-2'-deoxyuridine ( EUdR ) in combination with 5-fluorouracil (5-FU) has been studied on four human colorectal xenograft lines. In all lines the EUdR pretreatment potentiated the effect of 5-FU presumably due to the increased incorporation of 5-FU into RNA via elevated intracellular thymidine concentration and decreased rate of 5-FU catabolism.

Adenocarcinoma, Mucinous↗
PubMed1984

D-galactosamine-induced liver injury in immunosuppressed mice.

Thymectomized DBA/2 mice, irradiated with 720 rad/min and reconstituted with syngeneic bone marrow, were treated i.p. with 1 g/kg body weight D-galactosamine-HCl (DGA). Light and electron microscopic changes characteristic of the toxic effect of the agent, such as hepatocellular cytoplasmic inclusions and unicellular necrosis, could be observed but no inflammatory reaction was detectable in the liver. The phagocytic activity of Kupffer cells proved to be unchanged in immunosuppressed animals. Liver regeneration following DGA injury took place in 120 hours exactly as in animals having an intact immune system. The experiments suggested that T-lymphocytes participate in the development of DGA-hepatitis and their absence does not influence the restoration of liver injury. The experimental system described seems to be suitable for separating primary and secondary events and also for studying the role of the immune system in toxic liver injury.

Animals↗
PubMed1984

Further studies on the biochemical characterization of the MC-29 virus derived transplantable hepatoma (VTH). II. Modification of cyclic adenosine-3',5'-monophosphate levels by catecholamines, glucagon and Vinca alkaloids in normal chicken liver and VTH.

Basic and stimulated intracellular cAMP concentrations were measured in normal chicken liver and MC-29-virus-derived transplantable hepatoma (VTH) slices after in vitro incubation. Data indicated the preservation of catecholamine receptor but a loss of glucagon receptor in VTH. Comparing the relative stimulatory action of various catecholamines on cAMP concentration it was concluded that as in normal liver a predominantly beta 2-adrenergic receptor exists in the VTH, but its response to adrenaline is greater. Vinca alkaloids induced higher cAMP concentration in VTH than in normal liver. This stimulation was abolished by glucagon, while catecholamines and Vincristine acted in a synergistic manner on cAMP concentration.

Animals↗