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Biomedical subjects

W Rudin

Publications and source records attributed to W Rudin.

At least 55 records · Page 3Linked to original sources
PubMed1986

Demonstration of anti-cuticular antibodies by immuno-electron microscopy in sera of mice immunized with cuticular extracts and isolated cuticles of adult Dipetalonema viteae (Filarioidea).

The immunogold technique was used for the ultrastructural localization of antibody-binding sites on thin sections of Lowicryl K4M embedded adult females, infective larvae and pieces of adult cuticles of Dipetalonema viteae insoluble in SDS-2-ME. The antisera used were either produced against SDS-2-ME extracts of cuticles or the insoluble pellet after SDS-2-ME extraction. With both types of antisera a labelling of epitopes on fibers was achieved in intact cuticles. In isolated cuticles the corresponding structures were absent. The same sera crossreacted with the larval and microfilarial cuticle as well as with somatic structures of all three stages. The only serum against isolated cuticle, which did not recognize cuticle fibers also did not crossreact with somatic structures. The recognition of the electron dense cortical layer insoluble in SDS-2-ME depended on the number of immunizations. A labelling of the filarial surface was never achieved. A dense labelling of the apical membrane enfoldings of the hypodermis pointed to an involvement in the synthesis of the nematode cuticle. The rough endoplasmic reticulum in the apex of the epithelial cells of the uterus, the content of the nutrient channels, and the substance between eggshell and microfilariae crossreacted with most of the antisera. This led to the conclusion that these substances are partly produced by the uterus epithelium.

Animals↗
PubMed1985

The isolation and immunogenicity of the cuticle of Dipetalonema viteae (Filarioidea).

The cuticle of the filaria Dipetalonema viteae was isolated by sonication in 1% sodiumdodecylsulphate (SDS) and in a mixture of 1% SDS and 5% B-mercaptoethanol (BME). Sonication in SDS removed all internal parts and left the cuticle intact; this was verified by light- and electronmicroscopy. Sonication and incubation of the cuticle in the mixture of SDS-BME at pH 6.8 dissolved the basal and part of the median zone of the cuticle. The epicuticle and the cortical zone remained intact. The extracts were investigated using SDS-polyacrylamide gel electrophoresis; the early extracts contained a wide variety of proteins, whereas the later steps showed a consistent pattern with a smaller number of bands. Cuticles after SDS-purification, the extract of cuticular material in SDS-BME, and the cuticles insoluble in SDS-BME were used to immunize mice; the antibodies produced were visualized by an indirect fluorescent antibody test on cryostat sections of female worms. When SDS-purified cuticles were used for immunization, antibodies directed against all organs in the filariae were found. The SDS-BME extract and the insoluble cuticular pellet stimulated the production of antibodies restricted to the cuticle of adult worms and microfilariae. The purification method opens up the possibility of further isolation and characterization of antigens from the cuticle.

Animals↗
PubMed1985

Immunopathological aspects of trypanosomal meningoencephalitis in vervet monkeys after relapse following Berenil treatment.

Four quarantined vervet monkeys were treated with intramuscular Berenil in patent CNS infection after experimental trypanosome inoculation with Trypanosoma brucei rhodesiense or T. brucei brucei. All four animals relapsed in the post-therapeutic survival time of 37 to 209 days when they had fully developed meningoencephalitis in histological sections with the presence of interstitial intracerebral trypanosomes, which were confirmed in two monkeys by electron microscopy. In both, sequential samples of the serum and cerebrospinal fluid were analysed for circulating immune complexes, immunoglobulins and albumin. From these results the intracerebral IgG synthesis and the impairment of the blood-brain-barrier were calculated, both being present in advanced infection. Circulating immune complexes were present in the serum, but could not be demonstrated in the cerebrospinal fluid. The monkey model therefore permits the study of various aspects of cerebral trypanosomiasis. Berenil treatment is inefficient in patent CNS infection and leads to a protracted, less virulent disease course with terminal meningoencephalitis and intracerebral "persister" trypanosomes. This drug-induced trypanosome shift with meningoencephalitis could be used for chemotherapeutic purposes to test new compounds in late stage disease.

Amidines↗
PubMed1985

Trypanosomal cardiac valvulitis in vervet monkeys.

Quarantined vervet monkeys (Cercopithecus aethiops) were infected with Trypanosoma brucei (10(4) parasites/animal) in a tsetse free area. Thirteen monkeys (11 infected with T.b. rhodesiense and 2 with T.b. brucei) were studied. Animals became parasitaemic within one week after infection. The infection time lasted between 21 and 129 days; in 8 monkeys it was between 50 and 70 days. Macroscopically massive pericarditis was observed in one, pericardial effusion in one, small apical aneurysms in three. Microscopically all had pancarditis of moderate to marked degree including all 4 chambers, the apices and the valvular appendages. Trypanosomes and inflammatory cells were found in the interstitium of the 3 cardiac layers. Lymphatic drainage of trypanosomes and inflammatory cells was seen in all hearts, the lymphatic vessels showing signs of stasis. By light microscopy trypanosomes and inflammatory cells were also shown to occur in all four types of heart valves implicating diffuse valvulitis. In two instances electron microscopy confirmed the intact presence of the trypanosomes clustering in great numbers in the pars elastica of the valves. In the collagenous part, some intact single trypanosomes were seen between collagen fibres. No amastigotes were observed. These results point to select sites in organ topography which in turn may be relevant to active disease, chemotherapy and healing. The possibility of hiding places within the heart - protecting trypanosomes from the host defense and/or chemotherapeutic agents - ought to be considered.

Animals↗
PubMed1984

Electron-microscopic localization of Trypanosoma brucei gambiense transmitted by Glossina morsitans centralis in Microtus montanus.

In Microtus montanus infected with T. b. gambiense, electron microscopic examination of lymph nodes, spleen, liver, heart, choroid plexus and brain demonstrated extravascular populations of trypanosomes distributed throughout interstitial spaces, accompanied by a moderate cellular infiltration of plasma cells. The trypanosomes exhibited numerous profiles; some were dividing, others were in different stages of lysis, or phagocytosed. Penetration of trypanosomes into hepatocytes was observed. The present investigation indicated that trypanosomes migrated to the brain parenchyma from the Virchow-Robin spaces but could not confirm whether the parasites reached the Virchow-Robin spaces by traversing the ependymal cells lining the choroid plexus or by migrating through the endothelial cells of the cerebral blood vessels.

Animals↗
PubMed1983

Peritrophic membranes and protease activity in the midgut of the malaria mosquito, Anopheles stephensi (Liston) (Insecta: Diptera) under normal and experimental conditions.

Formation and solubility of the peritrophic membranes (pm) in the midgut (stomach) of female Anopheles stephensi depended on salt concentration in the gut lumen. High calcium drastically reduced the solubility of the pm in vitro. Thin-layer chromatography revealed the presence of N-acetylgalactosamine and galactose in the pm. In contrast to Aedes aegypti no N-acetylglucosamine was present indicating significant differences between Anopheles and Aedes mosquitoes with respect to pm formation and composition. Experimental distension of the stomach epithelium did not trigger secretion of proteases, but membrane-bound granules were released from the stomach cells, and pm were formed. When females were fed blood 18 hr after an enema with salt solution, when practically no granules were present in the gut cells, protease activity was increased, and blood was digested normally, but no pm were formed. A functional correlation of the membrane-bound granules and pm formation is postulated. alpha-Amanitin prevented normal digestion, protease activity was only insignificantly increased, and no pm formed after blood intake.

Animals↗
PubMed1982

Functional morphology of the midgut of a sandfly as compared to other hematophagous nematocera.

The midgut epithelium of female Lutzomyia longipalpis was investigated by means of electron microscopic morphometry before and during blood digestion. Ultrastructure and cytological changes of the stomach cells upon blood feeding were generally similar to the ones described for Phlebotomus longipes (Gemetchu, 1974) and for mosquitoes (Hecker, 1977). In addition, the quantitative composition of the cells resembled the one of mosquitoes in many respects. Despite some morphological differences in the functional gut cytology, it can be admitted that, in general, digestive processes may run similarly in the midguts of sandflies and mosquitoes.

Animals↗
PubMed1982

Comparison of surface iodination methods by electron microscopic autoradiography applied in vitro to different life-stages of Dipetalonema viteae (Filarioidea).

Different states of Dipetalonema viteae (males, females, microfilariae, and 3rd-stage larvae) have been iodinated in vitro under physiological conditions by chloroglycoluril, lactoperoxidase or chloramine T. The concentrations of the catalysts were correlated with the viability of the worms. Localization of the label with the different iodination methods had been visualized by electro microscopical autoradiography. Chloroglycoluril-mediated iodination is predominantly localized on the filarial cuticle. Lactoperoxidase-catalysed iodination is less specific and chloramine T catalyses iodination in a gradient decreasing from the cuticle to inner structures. It is necessary to visualize the labelling by electron microscopical autoradiography prior to biochemical and immunological experiments to avoid the extraction of structures iodinated by leakage of the catalyst into sub-cuticular regions.

Animals↗
PubMed1981

Morphometric parameters of the midgut cells of Aedes aegypti L. (Insecta, Diptera) under various conditions.

Previous morphometric or biochemical investigations have yielded different data on the distribution of free and membrane-bound ribosomes in midgut cells of Aedes aegypti. In the present paper ribosomal distribution has been morphometrically analysed to determine whether different mosquito strains, different food and different narcosis used in these previous studies, and/or methodological errors, could account for the different results. Most of the cellular parameters in the stomach epithelium of female A. aegypti, strain Rockefeller, and their changes during blood digestion, are comparable to those measured for another Aedes strain (Segemaganga, Hecker and Rudin, 1979), and ae generally similar to those of Anopheles stephensi (Hecker 1978). Proteolytic activity against casein is similar for both Aedes strains with a maximum activity being registered around 30 h after a blood meal. During digestion of human serum there is no increase in the ratio of membrane-bound to free ribosomes, and no significant increase in the surface area of the rough endoplasmic reticulum or of the number of bound or free ribosomes. Proteolytic activity is distinctly lower than during blood digestion. Immobilization of mosquitoes prior to dissection by either narcosis or by shaking in a test tube has no significant influence on cellular parameters in females fed on sugar solution and investigated 3 days after emergence. It is concluded that the differences in ribosomal parameters previously obtained by morphometrical (Hecker and Rudin 1979) and biochemical (Gander et al. 1980) methods, can only partly be explained by the selection of different food for the mosquitoes, and must also have been caused by methodological inadequacies.

Aedes↗
PubMed1980

Trypanosoma brucei brucei: a model for cerebral trypanosomiasis in mice--an immunological, histological and electronmicroscopic study.

The successful induction of cerebral trypanosomiasis in ordinary laboratory mice using Trypanosoma brucei brucei is reported. Sequential studies demonstrated the presence of trypanosomes in the interstitium of the choroid plexus at the fourth week after infection which correlated with the appearance of anti-trypanosomal antibodies, a rise of IgM and IgG serum levels and a rise of Clq binding activity as well as a decrease of C3 levels. Electronmicroscopic studies showed that the parasites were flagellated and localized extracellularly mainly in the interstitium of the choroid plexus. Granular immunofluorescent deposits of Ig and C3 were most marked in the choroid plexus. Electron-dense deposits suggestive of immune complexes were seen in subendothelial, interstitial and subependymal areas of the choroid plexus. Since autoantibodies to the brain were found in the serum of some mice, the possible involvement of autoimmune manifestations in the pathogenesis of cerebral lesions has to be considered. The pattern of inflammatory foci at the eighth week after infection was very similar to that observed in cerebral African trypanosomiasis in man. After treatment with ethidium bromide, trypanosomes persisted in the tissues when circulating parasites could no longer be detected. These observations suggest a sequential involvement of brain structures during African trypanosomiasis. Trypanosomes may first migrate from the vascular compartment into the interstitium of the choroid plexus, possible favoured by increased vascular permeability. Circulating immune complexes and complement activation may be involved at this state. Trypanosomes localized in the choroid plexus may then trigger a local immunologically mediated inflammatory reaction favouring the migration of trypanosomes into the CSF and further invasion of other cerebral structures.

Animals↗
PubMed1980

Studies on Dipetalonema viteae (Filarioidea). 5. Ultrastructural aspects of the antibody-dependent cell-mediated destruction of microfilariae.

The antibody-dependent cell-mediated destruction of Dipetalonema viteae microfilariae was followed by electron microscopy both in vitro and within micropore chambers in vivo. There was a correlation between the degree of adherence (1% mf with adhered cells) and the degree of microfilarial damage. Polymorphonuclear leukocytes, predominantly neutrophils, seemed to be responsible for the destruction of microfilariae in vivo. An in vitro assay indicated that eosinophils also have a role as potent effectors against microfilariae. The first sign of microfilarial damage is the disintegration of cuticular layers. In a later stage of destruction, lysis of the hypodermis or even of the whole microfilarial tissues was observed.

Animals↗
PubMed1979

Functional morphology of the midgut of Aedes aegypti L. (Insecta, Diptera) during blood digestion.

Morphometric analysis of the epithelial lining of the stomach of A. aegypti suggests that digestion of the first blood meal in the stomach of this species can be viewed as a series of phases that can be correlated with physiological data from the literature. In phase Ia (0-10 h after blood meal [abm]) the whorls of the rough endoplasmic reticulum unfold, the Golgi zones increase, and the basal labyrinth is enlarged. This coincides with processes of synthesis and secretion (e.g., peritrophic membrane, esterases and lipases) and transport by the stomach epithelium. In phase Ib (10-20 habm) the cellular parameters measured further increase, indicating high synthetic and secretory activities (e.g., digestive enzymes). In phase Ic (20-30 habm) cell structures involved in synthesis and secretion still exhibit high values coinciding with maximal activity of proteases in the gut. Enhanced surface area of microvilli, prominent lipid inclusions, and appearance of glycogen deposits in the gut epithelium suggest increased absorption, storage, and transport functions of the stomach cells. In phase II (30-36 habm) structural alteration points to a gradual shift from synthesis and secretion to absorption, partial storage, and transport of nutrients. In phase III (36-72 habm) the cellular apparatus is reduced concomitant with the ending of the digestive cycle. Lipid inclusions and glycogen deposits disappear from the stomach epithelium.

Aedes↗
PubMed1979

Normal versus alpha-amanitin induced cellular dynamics of the midgut epithelium in female Aedes aegypti L. (Insecta, Diptera) in response to blood feeding.

In midgut epithelial cells (stomach) of untreated female A. aegypti an increase in the surface area of the rough endoplasmic reticulum (rer) and in the ratio of membrane-bound to free ribosomes is morphometrically measured during digestion of the first blood meal. This can be correlated with the synthesis and release of digestive proteases. The dynamics of the ribosomes in A. aegypti are similar to those in A. stephensi. 3 ng alpha-amanitin per mosquito prevent normal blood digestion, the proliferation of the rer and the increase in the ratio of bound to free ribosomes. On the other hand, some synthesis of new ribosomes takes place.

Aedes↗
PubMed1977

Ultrastructural changes in midgut cells of female Aedes aegypti L. (Insecta, Diptera) after starvation or sugar diet.

The ultrastructure of the epithelial cells in the posterior part of the midgut in female Aedes aegypti was partly changed after starvation periods of 5 or 8 days. Most obvious is a drastic reduction of the amount of rough endoplasmic reticulum (rer), which is responsible for the synthesis of enzymes for blood digestion. A similar influence on rer membranes is to be observed in mosquitoes fed on sucrose solution only, without additional blood meals.

Aedes↗
PubMed1976

Morphometric comparison of the midgut epithelial cells in male and female Aedes aegypti L. (Insecta, Diptera).

Midgut epithelial cells of male and female Aedes aegypti, 3 days after emergence, were compared morphometrically. The results of the present investigation concerning the female, are in good agreement with those of a previous study (Hecker et al., 1974), demonstrating that morphometric investigation of midgut epithelia in A. aegypti can successfully be reproduced, and that the mosquito strain used did not show quantitative morphological changes due to laboratory rearing. In males, the cells of the anterior (A) and posterior part (P, 'stomach') of the midgut differ in their quantitative composition. Higher values are found for the microvilli and for the basal labyrinth in the A-part. On the other hand a higher volume density of the mitochondria is present in the P-part. No significant differences are found in the A-part between males and females. Significant differences, however, are present in the P-part. Distinctly more rer in the female stomach can be correlated with the synthesis of enzymes for blood digestion, which are absent in the male. In addition, the more complex functions of the female P-part are also reflected by higher values for other organelles and membrane systems (e.g. mitochondria, basal labyrinth).

Aedes↗