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Biomedical subjects

E Linder

Publications and source records attributed to E Linder.

At least 19 recordsLinked to original sources
PubMed1992

Schistosoma mansoni: praziquantel-induced tegumental lesion exposes actin of surface spines and allows binding of actin depolymerizing factor, gelsolin.

Praziquantel is widely used for treatment of schistosomiasis. Elimination of intravascular worms involves a combination of drug-induced changes at the worm surface and a host immune response against exposed parasite components. Loss of spines is a typical feature of schistosomes obtained from praziquantel-treated infected animals. The mechanism for this is unknown. We have considered the possibility that praziquantel treatment involves exposure of surface spines consisting of 'paracrystalline' actin and a subsequent host response against actin through mechanisms established in the host independently from schistosomal infection. Drug-induced exposure of actin was demonstrated by fluorescence microscopy using anti-actin antibodies and phallacidin, an actin-binding mushroom toxin. Actin spines remained intact at the schistosome surface after in vitro exposure, but spine morphology was lost after in vivo exposure to praziquantel. Disintegration of spines in vivo was associated with binding of host antibodies. In vitro spine destruction could be seen in the presence of normal human serum. The effect was linked to calcium-dependent binding of actin depolymerizing factor, gelsolin.

Actins↗
PubMed1992

Identification of a parasite-specific cytoplasmic 67 kDa Entamoeba histolytica antigen recognized by patient sera and monoclonal antibodies.

To avoid false positive reactions in tests for anti-ameba antibodies, we wanted to identify parasite-specific component(s). Amebiasis patient sera recognized an antigen of 67 kDa by immunoblotting in an active E. histolytica fraction obtained by ion exchange chromatography. Monoclonal antibodies against the fraction were made. Antibody 3G2 reacted with three antigenic components of 67, 40 and 25 kDa and in the immunocytology with an epitope located in the cytoplasm of E. histolytica trophozoites. ELISAs using the isolated parasite fraction and monoclonal antibody 3G2 (to assay inhibition of binding) were capable of distinguishing specific reactivity in sera from amebiasis patients.

Animals↗
PubMed1992

Schistosome antigen gp50 is responsible for serological cross-reactivity with Trichinella spiralis.

The 50-kDa component (gp50) present in Schistosoma mansoni eggs and secretions of the various life stages of the parasite was recognized by experimentally infected mice and by humans with S. mansoni, Schistosoma haematobium, and Schistosoma japonicum infection. All sera reacting with crude S. mansoni-soluble egg antigens (SEA) also reacted strongly with gp50 in enzyme-linked immunosorbent assay. No reactivity against gp50 was seen with sera from individuals without schistosomiasis, with the exception of sera from patients with Trichinella spiralis infection. All of 10 sera from patients with trichinellosis also reacted with schistosomes by immunofluorescence essentially recognizing testes, ovaries, ootype epithelium and ducts of the reproductive system. Cross-reacting antigens were seen in T. spiralis hypodermis, stichocytes and possibly germinal primordia using anti-gp50 monoclonal antibodies and anti-gp50-positive schistosomiasis patient sera. The results suggest that the anti-gp50 antibody response constitutes a significant part of the anti-SEA antibody response in infected individuals and is a major reason for the previously recognized serological cross-reactivity between T. spiralis and schistosome species.

Animals↗
PubMed1991

Isolation of an SBA lectin-reactive glycoprotein (gp50) and its identification in Schistosoma mansoni larval and adult worm secretions.

A major 50-kDa soybean agglutinin (SBA)-reactive component present in extracts of Schistosoma mansoni eggs was isolated by SBA lectin affinity chromatography. In polyacrylamide gel electrophoresis (PAGE), the SBA-reactive component was seen as a 100-kDa polypeptide band that after reduction and alcylation was substituted by a 50-kDa component. This suggests that it occurs in native form as a dimer. Monoclonal antibodies produced against gp50 reacted with miracidial and cercarial secretions and with adult worm components including tegumental structures suggestive of a secretory function.

Animals↗
PubMed1990

Expression of low molecular mass cytokeratins in oocytes of Schistosoma mansoni.

We studied the distribution of acidic 45 kDa keratin 18 and 40/42 kDa keratin 19 in Schistosoma mansoni, a trematode of medical importance in many tropical regions. The monoclonal antibodies which were produced against the cytoskeleton of mammary carcinoma cell line BT-20 recognized cytokeratins preferentially in parasite oocytes. As has been described in mammalian oocytes, the acidic cytokeratins were present in a nonfibrillar form. The two monoclonal antibodies also recognized testicular cells. No keratin immunoreactivity could be demonstrated by immunofluorescence microscopy at the larval stage, the miracidium. In immunoblotting, the molecular mass as determined by SDS-polyacrylamide gel electrophoresis of schistosome cytokeratins was about 15 kDa higher than that of the corresponding cytokeratins recognized by the monoclonal antibodies in BT-20 cells. The results suggest that acidic low molecular mass cytokeratins in trematodes have a phylogenetically conserved major function in oocytes which is unrelated to the documented cytoskeletal role in differentiated mammalian epithelial cells.

Animals↗
PubMed1990

Early antibody responses in human schistosomiasis.

Early diagnosis is important when handling patients with acute schistosomiasis. This state is usually more severe in travellers and tourists than in the immune, resident patients. With increased travelling to areas endemic for schistosomiasis, a tool is needed to solve the problem of differential diagnosis due to the non-specific symptoms of the early stages of the disease. Early appearance of antibodies against excretory/secretory antigens of the intestinal tract in the adult worm was seen in six individuals recently infected with Schistosoma mansoni, using an indirect immunofluorescence technique. The antibodies were of IgM, IgG and IgA classes, and of the IgG1, IgG3 and IgA1 subclasses as detected by ELISA using an antigen preparation of adult worm. On immunoblots, using a freeze-dried adult worm antigen, IgG1 and IgG3 antibodies recognized antigens of 32-35 kD. Antibodies against these antigens could thus be a marker of early infection in previously non exposed visitors to endemic areas.

Adult↗
PubMed1990

Acute schistosomiasis mansoni in Finnish hunters visiting Africa: need for appropriate diagnostic serology.

Three symptomatic and 3 asymptomatic patients with acute schistosomiasis mansoni are described. The index case presented with fever and eosinophilia 4-6 weeks after swimming in the Pipi River of the Central African Republic, suggesting acute schistosomiasis (Katayama fever). A fortunate early diagnosis led to early treatment of these schistosomiasis patients. Diagnosis was obtained based on the finding of one Schistosoma mansoni egg in the index case and positive serology in all cases. A commercially available passive haemagglutination test for serum bilharzia antibodies was negative in all cases prior to, and 2 weeks after treatment. However, antibodies against gut-associated antigens (GAA) of adult S. mansoni worms could be demonstrated using the indirect immunofluorescence technique. These cases illustrate the importance of using appropriate diagnostic assays for the early demonstration of infection by schistosomes in previously unexposed "nonimmune" patients with atypical symptoms and in asymptomatic individuals at risk even after brief exposure to schistosome-containing water in endemic countries. Careful (and repeated) stool examination and appropriate serological tests are the keys to prompt diagnosis of S. mansoni infection.

Adult↗
PubMed1989

Effect of heat on extracted HIV viral infectivity and antibody activity using the filter paper technique of blood sampling.

The diagnostic potential of the standardized filter paper technique at an outpatient clinic was further evaluated for individuals infected with HIV; the inactivation of HIV in dried blood from filter paper was also investigated. Heat treatment at 56 degrees C or 70 degrees C for 1 h did not demonstrably affect antibody activity as measured by enzyme-linked immunosorbent assay and Western blot. Prolonged treatment up to 18 h reduced the activity to some extent. Drying at room temperature of filter papers which had been soaked with HIV was sufficient to inactivate low, but not high, amounts of infectious virus. After exposure of the filter paper discs to 56 degrees C or 70 degrees C for 1 h, HIV could not be isolated from the extracts. The obvious advantage of blood collection on filter paper for serological studies makes it an alternative to venipuncture, especially when the blood might be contagious for HIV.

AIDS Serodiagnosis↗
PubMed1988

Pneumocystis carinii pneumonia: detection of parasites in sputum and bronchoalveolar lavage fluid by monoclonal antibodies.

Diagnosis of pneumocystis pneumonia is based on identifying Pneumocystis carinii cytochemically in material from the lung. The silver methenamine staining methods most commonly used are technically difficult and lack specificity. The diagnostic value of immunocytological identification of the parasite was evaluated by using mouse monoclonal antibody 3F6, specific for human pneumocystis, to identify P carinii in bronchoalveolar lavage fluid and sputum by immunofluorescence and was compared with that of other variables. Bronchoalveolar lavage was performed on 25 patients positive for HIV antibody with clinically suspected pneumocystis pneumonia and 40 patients negative for HIV antibody who presented with interstitial disorders of the lung. Lavage fluid showed pneumocystis only in the patients positive for antibody, the parasite being detected in 19 by immunofluorescence and in 17 by a modified silver methenamine staining method. Chest x ray films obtained at the time of bronchoscopy showed interstitial or alveolar shadowing in 17 of the 19 patients, but clinical symptoms and the presence of antibodies to pneumocystis did not seem to be predictive. Sputum samples were collected during 43 episodes of clinically suspected pneumocystis pneumonia in patients positive for HIV antibody. Pneumocystis was detected consistently more commonly by immunofluorescence than the silver strain in sputum collected routinely and induced by inhalation of saline. In 17 patients bronchoalveolar lavage followed sputum collection, and the sensitivity of detection of pneumocystis in immunofluorescence in sputum compared with lavage fluid was 57% (8/14). Immunofluorescence was suitable for specimens fixed in ethanol and seemed highly specific and more sensitive than the standard cytochemical methods for identifying pneumocystis.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Standardization of a filter-paper technique for blood sampling.

Blood sampling on filter paper has many potential advantages compared to sampling by venepuncture. However, the method is poorly standardized, and some variables affecting its usefulness were therefore explored; different filter papers were compared and an optimal elution procedure was determined. The quantity of eluted IgG, IgM and IgA was determined by single radial diffusion, and antibody activity was determined in an enzyme immunoassay. Comparison to serum titres was facilitated by calculation of the dilution factor. Filter papers containing drops of whole blood from a Swedish patient with Schistosoma mansoni infection were stored at different temperatures over different periods of time. Antibodies of different classes could be extracted and antibody activity demonstrated after up to 30 weeks of storage. The reproducibility of the technique was good, and comparison to serum titres can easily be calculated.

Animals↗
PubMed1988

Subclass distribution and IgE responses after treatment in human schistosomiasis.

The IgG and IgA subclass distribution of specific antibodies as well as the distribution of total and specific IgE in 15 patients with schistosomiasis was determined in consecutive samples before and after initiation of treatment. An adult worm antigen preparation and a soluble egg antigen preparation were used as antigens in the ELISA assays. After initiation of treatment a rise was noted in certain subclasses and a correlation was found for specific IgG1 and IgG4 serum levels in the egg-excreting patients against adult worm antigen and for specific IgG4 and IgE levels in sera from the eight patients with a chronic disease. They also had a rise of the specific IgA1 titre and six of them also of specific IgA2. Members of eosinophilic granulocytes reached a peak after 2 weeks in seven of the eight patients. The increase of eosinophils was an early event as opposed to the incidence of peak of the determined specific isotypes. The associated rise in IgG1, IgG4 and IgE antibody concentrations and eosinophils may suggest a causal relation possibly induced by common interleukins.

Adolescent↗
PubMed1987

Detection of Pneumocystis carinii in lung-derived samples using monoclonal antibodies to an 82 kDa parasite component.

Monoclonal antibodies against Pneumocystis carinii (PC) antigenic epitopes resistant to denaturing procedures were developed by immunization of mice with isolated parasites and a urea extract of infected human lung tissue. Paraffin sections of infected lung tissue were used as antigen in the screening for reactive clones. The target antigen was identified as an 82 kDa parasite specific component in immunoblotting. The antibody showed no cross-reactivity with human lung tissue and various rat tissues and failed to react with a number of parasites and fungi. The antigenic epitope recognized by the anti-82 kDa component was resistant to denaturing procedures involved in fixation and processing of tissues for histology. The antibodies could be used for identification of both cysts and trophozoites in fixed smears of infected lung tissue and bronchoalveolar lavage fluid from infected individuals.

Acquired Immunodeficiency Syndrome↗
PubMed1987

No evidence of hypersensitivity to dental restorative metals in oral lichen planus.

Twelve patients with oral lichen planus (OLP) suspected of dental restorative metal allergy were examined. All patients were patch tested with several metals including six different mercury compounds. One (8%) patient showed a positive patch test to two mercury compounds whereas no mercury allergy was found in a reference group of 17 patients suspected of dental restorative material allergy but without OLP lesions. The mercury allergic OLP patient was further tested on palatal mucosa but no reactions developed. Moreover, the energy dispersive X-ray microanalysis failed to show any contaminating metals in his OLP lesion. Mucosal biopsies were taken in close contact with amalgam fillings from nine OLP patients but these disclosed no evidence of lichenoid or dysplastic alterations. In OLP lesions, the immunofluorescence findings showed fibrinogen deposition, altered basement membrane and elastic fiber staining and intense Ulex europeaus I lectin fluorescence through all epithelial cell layers. Therefore, the present patch tests did not reveal increased frequency of mercury or other metal allergy in OLP patients and the mucosal biopsies failed to show any histologic or immunofluorescence alterations deviating from idiopathic OLP lesions.

Adult↗