PubMed Health⌕ Search

Biomedical subjects

E J Ruitenberg

Publications and source records attributed to E J Ruitenberg.

At least 91 records · Page 5Linked to original sources
PubMed1984

[Biotechnology and vaccine manufacture].

Modern biotechnology offers great possibilities for the large-scale manufacture of effective, safe and inexpensive vaccines. Improvements can also be expected in the manufacture of traditional vaccines, and there would appear to be prospect of producing vaccines against (tropical) parasitic disease for the first time. Close cooperation between university centres, research institutes and industry is essential to the development of biotechnology.

Netherlands↗
PubMed1984

Experimental screening of BCG preparations produced for cancer immunotherapy: safety and immunostimulating and antitumor activity of four consecutively produced batches.

Four consecutively produced batches of Bacillus Calmette-Guérin (BCG) especially intended to be used for cancer immunotherapy were investigated for consistency of the vaccine. Each batch was investigated directly after production of the vaccine, so that the four batches were not tested simultaneously. The activity of the four batches was investigated in general safety assays, immunostimulation assays, and two different tumor models. General safety assays showed dose-dependent growth retardation and increased serum glutamic pyruvic transaminase activity in mice, and a long-lasting temperature rise in rabbits after IV administration of the BCG preparations. In a skin reactivity assay, reactions were found acceptable for all preparations when compared with a reference batch. The results of the immunostimulation and antitumor studies can be summarized as follows. All four batches induced a specific delayed-type hypersensitivity reaction to PPD, indicating the induction of cell-mediated immunity. A stimulating effect on lymphoreticular organs was concluded from increased spleen weight and enhanced cell proliferation in draining lymph nodes. Enhanced macrophage function (phagocytosis and killing of bacteria) was demonstrated by an increased resistance to Listeria monocytogenes. YAC lymphoma target cells were killed nonspecifically by BCG-activated peritoneal exudate cells (PEC), indicating the induction of natural killing activity by BCG. Intralesional injection of BCG induced tumor regression in the guinea pig line 10 hepatocellular carcinoma, followed by immunity to the line 10 tumor. In the murine 5D04 squamous cell carcinoma, BCG had no effect on the primary tumor. However, IV-injected BCG resulted in a decreased number of lung metastases. In general, the four consecutively produced batches showed similar safety and activity in the immunostimulation assays and antitumor activity. Since only minor differences between the batches were found, which can also be attributed to the variation in experimental conditions common to biological assays, it is concluded that the vaccine batches produced show an acceptable consistency.

Alanine Transaminase↗
PubMed1984

Comparison of three methods for detection of prolonged experimental trichinellosis in pigs.

Three methods were employed for the diagnosis of porcine trichinellosis. The pooled sample digestion method and trichinoscopy served as European Community (EC) reference techniques, whereas the reliability of the Enzyme Linked Immunosorbent Assay (ELISA) was tested by 11 laboratories of the European Community and Sweden. Three groups of 6 piglets each were orally inoculated with 50, 150 and 1500 Trichinella spiralis larvae into each animal. Another group of 6 animals served as a non-infected control. Animals were slaughtered and serum and muscle samples were collected at Weeks 4, 12 and 40. The material was mailed under code and examined in all participating laboratories. ELISA proved to be a sensitive technique. ELISA micro assay was the most sensitive procedure. Of the direct techniques the reference pooled sample digestion method was more sensitive than trichinoscopy. It was concluded that both micro and macro ELISA can be used with confidence for the detection of low grade, longstanding experimental T. spiralis infections in swine.

Animals↗
PubMed1984

Myeloperoxidase is more efficient than eosinophil peroxidase in the in vitro killing of newborn larvae of Trichinella spiralis.

Myeloperoxidase (MPO) and eosinophil peroxidase (EPO) catalyse the formation of hypochlorite (OCl-) from chloride ions (OCl-) and hydrogen peroxide (H2O2). OCl- proved to be highly toxic for Trichinella spiralis newborn larvae (NBL) in in vitro assays. Using purified human MPO and EPO it was found that even at neutral pH both enzymes under appropriate conditions are able to kill NBL. The rate at which OCl- is produced is much lower in the EPO- than in the MPO-mediated reaction. This difference in enzymic activity may explain why in the MPO-mediated reaction half the amount of OCl- was sufficient to kill 50% of the NBL, as compared to the EPO-mediated reaction. Purified human eosinophil major basic protein showed excellent OCl- scavenging properties, resulting in a significant decrease in the EPO-mediated NBL killing. Addition of ammonium ions [(NH4)2SO4] to the EPO-mediated reaction increased the NBL killing remarkably. It was concluded that in vitro MPO is more efficient than EPO in killing NBL. Furthermore, it was suggested that although eosinophils show marked parasiticidal effects in various in vitro systems, their primary biological role might be the regulation of the inflammatory reactions.

Animals↗
PubMed1983

[Immunologic defense and inflammation in parasitic infections. The role of eosinophilic granulocytes].

The origin, kinetics and role of eosinophilic granulocytes in immune defense and inflammatory response in parasitism are reviewed. Particular attention was paid to the toxic action of eosinophilic granulocytes on parasites and the biochemical reactions which are of importance in these cases. Reference was also made to the regulatory role of eosinophilic granulocytes in inflammatory reactions, particularly in regard to mast cells. It was concluded that (1) several new insights into the role of eosinophilic granulocytes were gained in recent years, (2) that these cells can at any rate be said to have a dual function (viz. a directly parasitotoxic and regulatory role) and (3) a definite statement regarding the role of eosinophilic granulocytes in helminthic infections cannot so far be made.

Antibody Formation↗
PubMed1983

[Immunology - results of two decades of immunological research].

The discipline of immunology has made very rapid progress during the past twenty years. A general introductory part was followed by a discussion of immunological components in resistance. Subsequently, the importance of controlling the immunological system was stressed. The significance of the network theory was briefly referred to. Attention was then drawn to specific and non-specific stimulation of the immune response, which are essential both in theory and in actual practice. A number of instances are cited to illustrate these features in recent developments in the fields of preparation of vaccines and immunological treatment of cancer. It was pointed out that, during the past decades, the discipline of immunology not only made great strides in the field of human medicine and experimental animal models associated with this branch of medicine but also in that of veterinary medicine. It was predicted that immunology would also continue to be essential in the diagnosis, treatment and prevention of disease in animals.

Animals↗
PubMed1983

Rat mononuclear cells and neutrophils are more effective than eosinophils in antibody-mediated stage-specific killing of Trichinella spiralis in vitro.

The capacity of non-infected rat total, eosinophil-enriched and eosinophil-depleted fractions of peritoneal exudate and bone marrow cells to adhere to and kill Trichinella spiralis newborn larvae with immune rat serum has been studied in vitro. The eosinophil-depleted peritoneal exudate cell fraction contained mainly mononuclear cells, whereas the corresponding bone marrow cell fraction consisted of a considerable number of neutrophils. All cell types either originating from the peritoneal cavity or the bone marrow, showed adherence and killing properties to the Trichinella newborn larvae. It was concluded that mononuclear cells and neutrophils are capable of and more effective than eosinophils in stage-specific killing of Trichinella in vitro.

Animals↗
PubMed1983

The athymic nude rat. IV. Immunocytochemical study to detect T-cells, and immunological and histopathological reactions against Trichinella spiralis.

The anti-parasite response was investigated after oral infection of athymic nude (rnu/rnu) rats and heterozygous (+/rnu) littermates with 1000 muscle larvae of Trichinella spiralis. No IgM, IgG and IgE antibodies were detected in serum of rnu/rnu rats. Expulsion of adult worms from the small intestine was prolonged (worms were nearly all expelled at days 14 and 91 in +/rnu and rnu/rnu rats respectively). The yield of muscle larvae in the carcasses of nude rats at day 91 was 33 times higher than in +/rnu rats. In contrast to the strong inflammatory reaction in the parasitized tongue of +/rnu rats, no infiltration was observed in rnu/rnu rats. Using an immunoperoxide method with monoclonal anti-rat T-cell antibody, no T cells were identified in spleen, mesenteric lymph node and Peyer's patches. These data support earlier studies that the nude rat lacks functional T cells. As the counts of connective tissue mast cells (CTMC), intestinal mast cells (IMC) and globule leucocytes (GL) in small intestine of uninfected rnu/rnu rats were equal or higher than in +/rnu rats, it is concluded that the origin of these cells is thymus-independent. In contrast to +/rnu rats, infection of rnu/rnu rats induced no increase of CTMC, IMC or GL. Thus, these cells depend on T cells to undergo proliferation. Finally, results of this study were inconclusive whether IMC are precursors for GL, or that they represent independent cell populations.

Animals↗
PubMed1983

Increase of mucosal mast cells in the jejunum of patients infected with Trichinella spiralis.

The mast cell response in the mucosa and connective tissue of 36 jejunal biopsies of patients with clinically diagnosed trichinellosis, teniasis and lambliasis has been studied. Biopsy material was fixed in standard formalin or Carnoy's fixative, enabling differentiation between mucosal mast cells (MMC) and connective tissue mast cells (CTMC). With both fixatives CTMC could equally well be recognized. With Carnoy's fixative an additional population of mast cells (MMC) could be visualized both in the mucosa and the connective tissue. In the mucosa small mucosal mast cells were observed as well. Compared to the numbers of mast cells in the mucosa and the connective tissue of teniasis and lambliasis patients, the number of mast cells in trichinellosis patients only visualized using Carnoy's fixative was markedly higher. It was concluded that also in man trichinellosis is accompanied by an increase of cells with MMC characteristics. Further studies are needed to clarify the morphological and histochemical features of these cells and their possible role in this parasitic infection.

Biopsy↗
PubMed1983

The influence of different immunization pathways on the immunological response in the oral mucosa.

In order to study a possible difference in the induction of local immunological responses in the oral mucosa after different immunization pathways, Wistar rats were immunized with ovalbumin by different routes, (i) via the submandibular lymph nodes, (ii) via the Peyer's patches and (iii) via the hindpad. The local reaction after antigen challenge was compared with the systemic humoral response. To study the local reaction, the homologous antigen was injected in the oral mucosa. This resulted in a delayed type hypersensitivity reaction, being the same in extent and character for all immunization pathways. The humoral response was evaluated by serum antibody production (antiovalbumine IgG). It was shown that the antibody production obtained by immunization via the Peyer's patches was significantly smaller than that in the rats immunized via other pathways. The conclusion was that the induction of a local cellular reaction was independent of the antigen pathway, whereas serum antibody production depended on the route, i.e. antigen administration via the submandibular lymph nodes and the hindpad was significantly higher than via the Peyer's patches. The possible consequences of the findings are discussed together with their relevance to immunopathological reactions in the oral cavity.

Animals↗
PubMed1983

Antitumor activity, induction of cross-resistance, and nephrotoxicity of a new platinum analogue, cis-1,1-diaminomethylcyclohexaneplatinum(II) sulfate, and of cis-diamminedichloroplatinum(II) in an immunocytoma model in the LOU/M rat.

A newly synthesized platinum analogue, cis-1,1-diaminomethylcyclohexaneplatinum(II) sulfate (TNO-6), was compared with cis-diamminedichloroplatinum(II) (cis-DDP) for antitumor activity and nephrotoxicity. Antitumor activity was determined in an IgM immunocytoma model in the LOU/M rat. Tumor cells were inoculated on the left flank, and therapy was started when a tumor diameter of 10 to 30 mm was reached. At the start of the therapy, the primary tumor had already metastasized to the draining lymph node and liver. Both platinum compounds, dissolved in 5% glucose water, induced an almost complete tumor regression within 10 to 14 days (average, 84% tumor load reduction) and prolonged survival, compared to that of nontreated animals. The antitumor activity induced by repeated i.p. administration of cis-DDP and TNO-6 reached its maximum at a dose of 1.0 mg/kg body weight (twice a week for 7 weeks). This treatment regimen resulted in a highest tolerable dose for cis-DDP of 1.0 mg/kg and for TNO-6 of 2.0 mg/kg. However, when rats were treated with a 2.0-mg/kg dose of TNO-6, no increase in antitumor activity was obtained. For both platinum compounds, tumor recurrence occurred in almost all animals within 2 to 7 days after the maximum tumor load reduction. Tumors that recurred were found to be cross-resistant to both platinum compounds tested but were sensitive to treatment with doxorubicin (Adriamycin). With regard to toxicity, repeated administration of TNO-6 (1.0 mg/kg twice a week for 7 weeks) induced less decrease of body weight than did cis-DDP. For TNO-6, even in the highest dose investigated (2.0 mg/kg twice a week for 7 weeks), no nephrotoxicity was observed on histological examination of kidney and blood urea and creatinine values, whereas for cis-DDP nephrotoxicity was still present in the lowest dose investigated (0.5 mg/kg). From the comparison of the antitumor activity and nephrotoxicity of TNO-6 and cis-DDP, administered i.p. in 5% glucose solution, it is concluded that both drugs have comparable antitumor activity and potency. In contrast to the effects of cis-DDP, no nephrotoxicity was observed with TNO-6; thus, TNO-6 might be a good alternative to cis-DDP in avoiding nephrotoxicity during platinum therapy.

Animals↗
PubMed1982

Intestinal mast cells and their relation to mesenteric lymph nodes.

The data presented in this paper support a common source for intestinal mast cells in intestinal mucosae. IMC precursors and/or mastocytopoietic factors of as yet unknown origin could be transferred by immune mesenteric lymph node (IMLN) cells of thymus-bearing mice. The differentiated locally or induced mastocytopoiesis in Trichinella spiralis infected mucosal sites, but only in animals with a normal thymus function. Antigen-stimulated precursor cells either in the gut or in the mesenteric lymph node to enter the circulation and home to both parasitized and nonparasitized mucosal sites. Both proliferation in the mesenteric lymph node and in the intestinal mucosae were shown to be thymus-dependent. The injected IMLN stimulated only the proliferation of IMC and not of globule leucocytes. This might indicate that cells relevant for IMC proliferation are different from those essential for GL proliferation.

Animals↗
PubMed1982

Effect of fixation on the light microscopical visualization of mast cells in the mucosa and connective tissue of the human duodenum.

Mast cells have been studied in the mucosa and connective tissue of 28 biopsies of human duodenum. They were collected from individuals who for various reasons had to undergo upper intestinal endoscopy. Tissues were fixed in both standard formalin and a formalin-acetic acid (FA) fixative developed for visualization of mucosal mast cells. With both fixatives connective tissue mast cells (CTMC) were equally well recognized. Only with the FA fixative, an additional population of mast cells was observed both in the mucosa and the connective tissue. The population consisted of round cells, always smaller than CTMC, with a number of granules staining violet with toluidine blue. These mast cells comprised two cell types, differing in size, the larger being present in both the mucosa and the connective tissue, the smaller ones in a subepithelial position in the crypts of Lieberkühn and in the adjacent submucosa. It was suggested that this first mentioned additional population was similar to the mucosal mast cells (MMC) observed in rats and mice. The subepithelially located metachromatic cells differed in morphology from the globule leukocytes found in rats and mice. It was concluded that in the human duodenum a population of cells with MMC staining characteristics is present, which can only be visualized under special fixation conditions. Their further characterization and role in various disease conditions remains to be elucidated.

Acetates↗
PubMed1982

Thymus dependence of the adoptive transfer of intestinal mastocytopoiesis in Trichinella spiralis-infected mice.

The relationship between the gut and mesenteric lymph node in the kinetics of mucosal mast cells (MMC) was further analysed. A Trichinella-induced synchronous proliferation of MMC occurred in the intestine of thymus-bearing and not in athymic mice, both at sites of parasite invasion (jejunum) and elsewhere (caecum) and in the mesenteric lymph node. The mastocytopoietic ability could be adoptively transferred with immune mesenteric lymph node cells to the jejunum and caecum of infected thymus-bearing recipients. The enhanced mastocytopoiesis which was both antigen- and thymus-dependent, was only observed for the stroma intestinal mast cells (IMC) and not for the intraepithelially located globule leucocytes (GL). The data suggest a common source for IMC in intestinal mucosae and support the idea that IMC and GL are two independent cell populations.

Animals↗