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Biomedical subjects

F Martin

Publications and source records attributed to F Martin.

At least 451 records · Page 25Linked to original sources
PubMed1985

Interaction between two cellular subpopulations of a rat colonic carcinoma when inoculated to the syngeneic host.

From a single, chemically-induced rat colonic carcinoma, two subpopulations of tumor cells have been isolated. When injected into syngeneic rats, TR cells give rise to progressive tumors in most of the animals, whereas TS cells give rise to no tumors or to tumors which regress in less than 30 days. TS cells inhibit the growth of TR tumors, whether they are injected before TR cells or simultaneously, at a different site or mixed with the TR cells. Lymph nodes and spleen lymphocytes from animals having rejected TS tumors also inhibit TR-cell growth. On the other hand, TS cells are able to give rise to progressive tumors when they are injected into rats bearing established TR tumors. Lymph nodes and spleen cells of TR tumor-bearing rats are able to enhance TS cell growth. These results suggest that subpopulations of cancer cells contained in the same tumor interact with each other through their effect on the host immune system. The growth of a whole tumor probably depends not only on the growth potential of each constituent subpopulation, but also on the interaction between the subpopulations themselves.

Adenocarcinoma↗
PubMed1985

Nucleotide sequence analysis of a cDNA encoding human ubiquitin reveals that ubiquitin is synthesized as a precursor.

Ubiquitin is a 76-amino acid protein whose sequence is highly conserved throughout evolution from invertebrates to mammals. It is both a cytoplasmic and nuclear protein. In the cytoplasm it is involved in ATP-dependent nonlysosomal proteolysis. In the nucleus, ubiquitin is conjugated to histone 2A and may play a role in regulation of chromatin structure and/or regulation of transcriptional activity. During attempts to identify a cDNA encoding somatomedin-C (insulin-like growth factor I) we screened a fetal human liver cDNA library with a mixture of 17 base oligonucleotides corresponding to a portion of the B chain of somatomedin-C. One oligonucleotide of the mixture hybridized to two cDNAs encoding ubiquitin despite a 2-base pair mismatch. Nucleotide sequence analyses of the 350- and 516-base pair cDNAs revealed that they correspond to the same ubiquitin mRNA. The coding sequence of the 516-base pair cDNA begins at amino acid 5 of the ubiquitin sequence and encodes amino acids 5 through 76 of ubiquitin, an 80-amino acid carboxy-terminal extension, a 3' untranslated region, and a poly(A) tail. The finding that ubiquitin is synthesized as a precursor raises the possibility that the precursor sequence may be important in compartmentalization of ubiquitin or ubiquitin precursors. Analyses of ubiquitin mRNAs in poly(A) RNA extracted from human liver and various rat tissues reveals that there are three distinct mRNAs encoding ubiquitin in humans and four mRNAs in the rat.

Amino Acid Sequence↗
PubMed1985

Role of macrophage in the defense against intestinal cancers.

The capability of activated macrophages to kill tumor cells in vitro is now well documented. The tumoricidal activation of macrophages against intestinal tumor cells by different agents is described and the main hypothesis on the mechanisms of tumor cell killing in vitro are discussed. These in vitro results suggest that the macrophage can constitute an efficient effector cell in the defense against intestinal tumors. The distribution and ratio of macrophages in normal intestine and intestinal tumors is described. At the moment, potent activators of macrophages studied in vivo on experimental and human intestinal tumors give poor results or even enhance the growth of tumors. Macrophages may also interfere with the specific immune response in two directions by enhancing the immune response or decreasing it by elaboration of mediators such as prostaglandins.

Animals↗
PubMed1985

Synergistic effect of liposomes and endotoxins on the activation of rat macrophage tumoricidal activity.

Macrophage biological responses to endotoxins have been extensively studied; nevertheless, the mechanisms by which endotoxins activate macrophage tumoricidal activity are not currently understood. We used liposomes to investigate the interaction of endotoxins with macrophages. In a medium containing 10 micrograms endotoxin/ml, macrophage-mediated cytolysis ranged from -7 to 36%. In all the experiments, 1mM dipalmitoyl phosphatidyl choline (DPPC) small unilamellar liposomes significantly induced or enhanced cytolysis, ranging from 30-90%. Liposomes and endotoxins had a synergistic effect on the macrophage cytolytic activity. This effect was dose-dependent on liposome concentration, ranging from 0.25-1 mM or 2 mM. Liposomes decreased the endotoxin concentration threshold necessary to induce cytolysis. They did not modify the kinetics of macrophage activation. Liposomes did not modify the binding of tumor cells to macrophages. The optimum synergistic effect was obtained when liposomes were present during the first 18 h of the mixed culture of macrophages and target cells, before adding endotoxins for the next 18 h. When cholesterol was added to DPPC (M/M), liposomes did not enhance but rather inhibited macrophage activation by endotoxins.

Animals↗
PubMed1985

[Limulus test using a chromogenic method: application to the control of pyrogens in blood derivatives].

We report here the application of the LAL Test to a chromogenic substrate to detect endotoxins in Human Blood Products. In order to reduce the cost, we used a microplate procedure with the Multiskan Reader. Quantitative results in the range of 0,01 to 0,1 ng/ml allowed for a good correlation with the Rabbit Pyrogen test. For 20% albumins and 4% albumins, the mean endotoxins levels of non pyrogenic lots were 0,38 +/- 0,18 and 0,09 +/- 0,03 ng/ml. All the lots which passed the Rabbit Pyrogen test had endotoxins levels lower than 1 ng/ml and 0,2 ng/ml, respectively. We can use this test for other plasma derivatives; Gammaglobulines and PPSB are easily tested. Dried Concentrated Antihemophilic Factor and Dried plasma contain citrate which inhibits the reaction. Dilution and Addition of Calcium Chloride overcome this inhibition. For dried plasma, we should destroy plasma inhibitors by heating at 75 degrees C. This sensitive and reproductible in vitro assay improves the control of pyrogenecity in Human Blood Products.

Blood Transfusion↗
PubMed1985

Quantitative spectral evaluation of shimmer and jitter.

A vowel [a]-like, synthesized speech wave was perturbated by defined and comparable jitter and shimmer levels. The signal-to-noise ratio was calculated from the speech wave spectra. Noise emerges in those spectral regions in which the harmonics have high amplitudes, that is, at low frequencies and in the formant regions. Jitter created noise levels significantly higher than shimmer. To verify the theoretical findings, the voices of 32 women with functional voice disorders were analyzed for shimmer and jitter. It was found that only jitter is relevant for differentiating between hypo- and hyperfunctional voice disorders. Jitter was reduced in hyperfunctional voice disorder. This is presumed to be an effect of the high vocal fold tension found in the disorder.

Adult↗
PubMed1985

Cloning and expression of the human erythropoietin gene.

The human erythropoietin gene has been isolated from a genomic phage library by using mixed 20-mer and 17-mer oligonucleotide probes. The entire coding region of the gene is contained in a 5.4-kilobase HindIII-BamHI fragment. The gene contains four intervening sequences (1562 base pairs) and five exons (582 base pairs). It encodes a 27-amino acid signal peptide and a 166-amino acid mature protein with a calculated Mr of 18,399. The erythropoietin gene, when introduced into Chinese hamster ovary cells, produces erythropoietin that is biologically active in vitro and in vivo.

Amino Acid Sequence↗
PubMed1985

C Nuclear Magnetic Resonance Study of Mannitol Cycle and Trehalose Synthesis during Glucose Utilization by the Ectomycorrhizal Ascomycete Cenococcum graniforme.

(13)C nuclear magnetic resonance spectroscopy has been used to follow the utilization of glucose for the synthesis of carbohydrates in the ectomycorrhizal ascomycete Cenococcum graniforme. The fate of (13)C label was analyzed in vivo and in mycelial extracts. The major carbohydrates produced from [1-(13)C]glucose and [6-(13)C]glucose were mannitol and trehalose. Mannitol was mainly synthesized via a direct route from glucose. Scrambling of the (13)C label was observed to occur in trehalose during glycolysis. From the analysis of the scrambling patterns, it is concluded that the mannitol cycle was operative and that a large part of the carbon of glucose was used to form trehalose after cycling through the mannitol pool. The activities of NAD-mannitol-l-P dehydrogenase (EC 1.1.1.17) and NADP-mannitol dehydrogenase (EC 1.1.1.138), which participate in the mannitol cycle relative to the activity of glycolytic enzymes, provide evidence that the cycle is important for NADPH production.

Journal Article↗
PubMed1985

Differences in the tumoricidal activation of rat and mouse macrophages by endotoxins.

Conventional and specific pathogen-free rat resident peritoneal macrophages were lytic to tumor cells in the presence of endotoxins even when not elicited or not stimulated in vivo or in vitro. In contrast, conventional mouse resident peritoneal macrophages were not cytolytic in the presence of endotoxins. The induction by endotoxins of rat macrophage-mediated cytolysis was only obtained after the binding of tumor cells by macrophages. Rat resident peritoneal macrophages bound faster and stronger to tumor cells than mouse resident peritoneal macrophages. These differences in binding could explain the species differences in the tumoricidal response to endotoxins.

Animals↗
PubMed1985

Alcoholic muscle disease.

Histopathological abnormalities of muscle are common in chronic alcoholics and can be classified into the rare acute myopathy, with myonecrosis, and the much more common chronic myopathy, with a selective atrophy of type II muscle fibres (particularly IIb fibres). The patients may often be asymptomatic and, except for florid cases of acute rhabdomyolysis, clinical features do not help to distinguish the two. Serum creatine kinase activity is an insensitive guide to the presence of the muscle abnormalities. These abnormalities cannot be adequately explained by co-existing alcoholic liver disease, malnutrition or peripheral neuropathy, and probably represent the result of direct toxicity to the muscle fibres. Acute myopathy may occur as a result of damage to cell membranes although intracellular phosphate deficiency has also been proposed as a crucial factor. Atrophy of type II fibres occurs in other metabolic myopathies and its development in chronic alcoholism could represent the result of metabolic or endocrinological derangement induced by ethanol. Alternatively, direct toxicity to muscle cell pathways of carbohydrate catabolism or fatty acid oxidation may occur. Previous suggestions of enhanced muscle breakdown in chronic alcoholics is contested by recent work and reduced protein synthesis may be of more pathogenic importance. Abstention from alcohol reverses the muscle abnormalities.

Adenosine Triphosphate↗
PubMed1985

Alcoholic skeletal myopathy, a clinical and pathological study.

One hundred and fifty-one inpatients with a history of chronic heavy alcohol intake were examined for evidence of muscle disease. Ninety-two patients (60 per cent) had histologically abnormal biopsies of the quadriceps muscle. The most common abnormality, which was often severe, was type II muscle fibre atrophy. Seven patients (5 per cent) had histological evidence of acute myopathy, one of whom presented with the full clinical picture of acute rhabdomyolysis. Twenty-three patients had cirrhosis, 36 were significantly malnourished and 98 had evidence of a peripheral neuropathy. None of these features, however, were sufficient to account for the muscle abnormalities. There was no clear relationship between musculo-skeletal symptoms and muscle biopsy histology. Serum creatine kinase activity was elevated in only 23 subjects and was an insensitive indicator of subclinical acute myopathy and of chronic alcoholic myopathy. Follow-up studies after abstinence from alcohol invariably showed both objective and subjective improvement of muscle function - often in the absence of any clinical recovery from the peripheral neuropathy. Continued alcohol consumption was accompanied by persistence and often deterioration of muscle fibre atrophy. It is concluded that chronic skeletal myopathy is a frequent consequence of alcohol abuse and may result from a direct toxic effect of ethanol on muscle fibres.

Acute Disease↗
PubMed1985

[Diagnostic value of a new serum marker of human digestive cancer: the carbohydrate antigen 19.9; comparison with the carcinoembryonic antigen].

In order to evaluate its diagnostic value for digestive cancers, the carbohydrate antigen 19.9 (CA 19.9) was quantitated by radioimmunoassay in the serum of 102 patients suffering from malignant or non-malignant diseases of the digestive or pulmonary tract and of 20 healthy subjects. The carcinoembryonic antigen (CEA) was quantitated by enzyme-immunoassay in the same sera. No correlation was found between the CA 19.9 and the CEA levels. The sensitivity of the CA 19.9 test for the detection of digestive cancers (0.51) was not significantly higher than neither that of the CEA assay (0.46), nor that of the combined tests (0.59). Numerous false positive results were encountered in the CA 19.9 assay in pulmonary diseases and in non-cancerous liver diseases, especially cirrhosis. Its specificity (0.84) did not prove to be superior to that of CEA (0.90). Thus, in our experience, the clinical interest of serum CA 19.9 determination for the diagnosis of digestive cancers seems doubtful.

Antigens, Neoplasm↗
PubMed1985

[Dysontogenetic median maxillary cysts].

Nasopalatine duct cysts, median palatine cysts and nasoalveolar cysts belong to the developmental cysts of the upper jaw. They are situated at the midline in the fusion areas of embryonic facial processes and for this reason are known as "fissural cysts". They are, therefore, not of odontogenic origin and, on account of their relationship to the mouth, the nose and the nasal cavities, are of practical relevance to the otolaryngologist. The various clinical symptoms and the histological findings are described, and a review of the literature is presented.

Bone Cysts↗
PubMed1985

Comparative effect of muramyl dipeptide in vivo and in vitro on the tumoricidal activity of rat peritoneal macrophages.

Muramyl dipeptide (MDP) has been tested for its ability to induce rat peritoneal macrophage tumoricidal activity. Rat resident macrophages were activated in vivo and in vitro. Nevertheless, they were cytolytic when harvested 1 or 2 h after an intraperitoneal injection of MDP, but noncytolytic when harvested later. The activation obtained in vivo and in vitro with small amounts of MDP was not increased with larger doses. As, under the same conditions, mouse peritoneal macrophages were not activated, the sensitivity of the peritoneal macrophages to MDP depends on the species used.

Acetylmuramyl-Alanyl-Isoglutamine↗