Biomedical subjects

K Janitschke

Publications and source records attributed to K Janitschke.

At least 19 recordsLinked to original sources

PubMed1998

Blinded, externally controlled multicenter evaluation of light microscopy and PCR for detection of microsporidia in stool specimens. The Diagnostic Multicenter Study Group on Microsporidia.

The quality parameters for the detection of microsporidia in identical sets of 50 stool samples were determined for six laboratories where technicians used light microscopy and for six laboratories where technicians used PCR. The average overall sensitivities were 67% (89% for patient samples only) for the PCR laboratories and 54% (80% for patient samples only) for the light microscopy laboratories. Specificities were 98 and 95%, respectively. Differences in results were most apparent between the individual laboratories rather than between the two major methods used.

Animals↗

PubMed1997

Light and electron microscopy study of carbohydrate antigens found in the electron-lucent layer of Pneumocystis carinii cysts.

The localization and biochemical nature of antigens found in the electron-lucent layer (ELL) of Pneumocystis carinii cysts using polyclonal rabbit antibodies are described. These antigens, specific for the cystic stages of the parasite, were shared by organisms from different hosts, suggesting that they represent functionally important components of the cyst cell wall. The binding sites were situated on an interwoven net of fibrils in the ELL produced by mild to strong proteolysis. Degradation of this residue by glucanase and chitinase confirms that this layer contains branched glucan and chitin. In contrast, the prompt susceptibility of the polysaccharide-rich ELL to proteolysis reveals that proteins are also relevant in building up the cyst-wall glucan skeleton. It is therefore concluded that the formation of the Pneumocystis cyst wall shows differences to the typical fungal cell-wall architecture. The taxonomical debate regarding this unique protist is ongoing, and consideration of these immunological and morphological findings may be useful for the study of the biology and phylogeny of Pneumocystis.

AIDS-Related Opportunistic Infections↗

PubMed1996

Animal model Balamuthia mandrillaris CNS infection: contrast and comparison in immunodeficient and immunocompetent mice: a murine model of "granulomatous" amebic encephalitis.

Balamuthia mandrillaris and several species of Acanthamoeba are pathogenic "opportunistic" free-living amebas which cause granulomatous encephalitis (GAE) in humans and animals. The granulomatous component is negligible or absent, particularly in immunocompromised individuals. GAE is an "opportunistic" infection, usually seen in debilitated, malnourished individuals, in patients undergoing immunosuppressive therapy for organ transplants, and in Acquired Immunodeficiency Syndrome (AIDS). From around the world 156 cases of GAE have been reported from 1956 through October 1, 1995, 59 (26 in the USA) of them caused by B. mandrillaris, at least seven of them in AIDS patients. The present study was designed to compare and contrast the susceptibility of infection, the rate of infectivity and the histopathological changes within the CNS between the mutant, severe combined immunodeficient mice (SCID) infected with B. mandrillaris and the normal immunocompetent BALB-C mice. The SCID mouse is severely deficient in B and T lymphocytes, therefore lacking immunoglobulin and cell-mediated immunity. This mouse is also prone to develop early T cell lymphomas. One thousand amebic trophozoites and cysts of B. mandrillaris were intranasally and intraperitoneally inoculated in both strains in mice. Seventy percent of the intranasally inoculated SCID mice died due to CNS infection. Amebic trophozoites and cysts were found within CNS parenchyma without inflammatory response. Death occurred from 2 to 4 weeks after inoculation. By contrast only 10 percent of the intranasally inoculated BALB-C mice died with CNS infection showing the characteristic features of GAE. None of the intraperitoneally inoculated mice developed amebic infection. The SCID and BALB-C mice were logical models to study the structural alterations within the CNS of B. mandrillaris infection. This animal model recapitulates with excellent degree of fidelity several aspects of the pathogenesis and histopathological features of free-living amebic infection in human beings.

Amebiasis↗

PubMed1995

[The detection of Toxoplasma gondii in abortion tissues of sheep using the polymerase chain reaction].

A polymerase chain reaction was applied to detect Toxoplasma gondii DNA in placental and fetal tissue samples of 47 unselected ovine abortions of the lambing season 1990/91 (Baden-Württemberg, Rhineland, Hesse). For the amplification a 190 bp or 223 bp sequence of the B1-gene of T. gondii was selected as the target sequence. Both sequences were detected in five abortions. All positive results were immunohistochemically confirmed using the peroxidase antiperoxidase technique (PAP-staining). Thus, in Germany, too, T. gondii infection in sheep during pregnancy should be considered as a possible cause of abortions, particularly in case of abortions of unknown genesis.

Abortion, Veterinary↗

PubMed1995

[Imported parasitic diseases].

A review is given on parasitic infections imported to Germany. A complete history of travel into foreign countries is of particular importance for the determination of necessary diagnostic parameters. The possibilities of the laboratory diagnosis are described.

Cross-Sectional Studies↗

PubMed1995

Comparison of three DOT-ELISA techniques in diagnosing Schistosoma haematobium infection.

The DOT-STRIP-ELISA was evaluated in the laboratory as a serodiagnostic tool for Schistosoma haematobium infection in order to assess the potential of introducing the technique under field conditions in the developing world. Out of 100 individuals with parasitologically confirmed Schistosoma haematobium, 87 reacted positively (sensitivity 87%), whereas 45 out of 50 sera from individuals from a non-endemic area reacted negatively (specificity 90%). Results were reproducible. Cross-reactions were observed with sera from individuals infected with Schistosoma mansoni, Echinococcus, Leishmania and Wuchereria. The DOT-STRIP-ELISA offers more advantages with regard to practicability and test-time when compared with the DOT-DISC-ELISA and DOT-MILLIPORE-ELISA.

Case-Control Studies↗

PubMed1994

ELISAs based on recombinant antigens for seroepidemiological studies on Toxoplasma gondii infections in cats.

Two recombinant Toxoplasma gondii polypeptides, H4 and H11, were tested as diagnostic antigens in enzyme-linked immunosorbent assays (ELISAs). The results obtained by ELISAs based on single H4 (H4-ELISA), on single H11 (H11-ELISA) and on a mixture of H4 and H11 (H4/H11-ELISA) were compared with results obtained by an ELISA based on traditional ELISA antigen (TEA-ELISA), an indirect fluorescent antibody test (IFAT), the Sabin-Feldman dye test (SFDT) and a direct agglutination test (DAT). A total of 306 cats from a suburban cat population were tested of which about 45% showed serological evidence of T. gondii infection. Infection rates varied from about 32% for cats kept indoors to about 55% for stray cats. Specificities > 99% were observed for all ELISAs based on the recombinant antigens (H4-ELISA, H11-ELISA and H4/H11-ELISA). The H4/H11-ELISA also reached a sensitivity of 95% which compared very favourably with those observed for the TEA-ELISA (98%) and for the IFAT (94%). Negative and positive predictive values for the H4/H11-ELISA were 96 and > 99%, respectively. Antibody titres measured by the H4/H11-ELISA also correlated well with those measured by the SFDT and the DAT. Hence, the H4/H11-ELISA appears to be a very suitable test for sero-epidemiological studies on T. gondii infections in cats.

Age Factors↗

PubMed1994

Value of PCR for evaluating occurrence of parasitemia in immunocompromised patients with cerebral and extracerebral toxoplasmosis.

PCR was used to evaluate the occurrence of Toxoplasma gondii parasitemia by detection of the B1 gene in blood samples in two groups of immunosuppressed patients (148 subjects) suspected of having cerebral or extracerebral infection, respectively. Group I consisted of 52 patients with AIDS with suspected cerebral toxoplasmosis. The diagnosis was clinically proven in 15 cases. Parasitemia was detected by PCR in only two of these patients (13.3%), both showing evidence of disseminated infection. Group II consisted of 96 immunocompromised patients, either with AIDS or receiving iatrogenic immunosuppressive therapy. Of these patients, 65 (34 with AIDS and 31 others) showed abnormalities only in chest radiography and were first screened for the presence of Toxoplasma DNA in bronchoalveolar lavage fluid. Blood was then analyzed when the parasite was detected in the bronchoalveolar lavage fluid. The remaining 31 subjects (22 with AIDS and 9 others) were suspected of having extracerebral, pulmonary, or disseminated toxoplasmosis, and blood was studied directly in these cases. Among the nine patients with clinically diagnosed extracerebral infection in group II, the parasite was detected by PCR in the blood of five patients (55.5%), all having pulmonary toxoplasmosis. If all patients with clinical manifestations of extracerebral toxoplasmosis (from both groups) who had not received antitoxoplasma therapy when the samples were collected are considered, PCR detected parasitemia in seven of the nine cases (77.8%). The present study indicates that examination of blood by PCR may be valuable in cases of extracerebral toxoplasmosis because of the disseminated nature of the disease. Since most cases of cerebral toxoplasmosis result from the local reactivation of latent brain cysts, detection of parasitemia by PCR is useful only in cases associated with severe cerebral infection or dissemination of this disease.

Acquired Immunodeficiency Syndrome↗

PubMed1993

Extracerebral toxoplasmosis in AIDS. Histological and immunohistological findings based on 80 autopsy cases.

Despite the great amount of literature concerning toxoplasmic encephalitis in AIDS patients, little is known about extracerebral toxoplasmosis. Therefore we conducted a study of 80 autopsy cases to estimate the frequency of extracerebral toxoplasmosis. A control group of 50 cases was completely negative for all markers applied. In 35 of the 80 AIDS-cases (43.7%), organisms could be detected. In 13 cases (16.2%) there was an extracerebral toxoplasmosis; 4 cases (5%) showed only extracerebral involvement and in 9 cases (11.2%), extracerebral toxoplasmosis occurred in combination with cerebral manifestations. In 22 cases (27.5%), only cerebral toxoplasmosis was found. The following organs were involved: cardiac muscle (15%), lungs (6.2%), liver (5%), pancreas (5%), gastrointestinal tract (6.2%), adrenal glands (5%), lymph nodes (5%) and testis (3.7%). In individual cases further organs, not mentioned above, were involved. Pseudocysts could be demonstrated within necroses and inflammatory foci by conventional staining, whereas trophozoites became apparent only immunohistologically.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Application of the polymerase chain reaction in the diagnosis of pulmonary toxoplasmosis in immunocompromised patients.

Bronchoalveolar lavage (BAL) fluid from 47 immunocompromised patients (26 with AIDS and 21 patients on immunosuppressive therapy) was analysed for the presence of Toxoplasma gondii DNA by means of the polymerase chain reaction (PCR). Specific target DNA derived from the B1 and P30 gene of Toxoplasma gondii was detected in BAL fluids from three patients with AIDS (6.4%). Pneumonia as the presenting feature of disseminated toxoplasmosis was confirmed by both clinical findings and by detection of Toxoplasma gondii DNA in blood obtained from two patients. The findings indicate that PCR has potential value in the detection of Toxoplasma gondii as an etiologic agent of atypical pneumonia in immunocompromised patients.

Animals↗

PubMed1992

Improved sensitivity of the polymerase chain reaction for detection of Toxoplasma gondii in biological and human clinical specimens.

The aim of the present study was to improve the sensitivity of the polymerase chain reaction for detection of Toxoplasma gondii in biological and clinical specimens. Using a pair of primers amplifying a 634 bp fragment of the B1 gene of this parasite, it was possible to detect ten parasites in 100 microliters of sample suspensions containing a high concentration of concomitant host cells. A comparison of different DNA purification methods indicated that cell-rich clinical specimens intended for use as samples for the polymerase chain reaction should be digested with proteinase K prior to DNA amplification. By using the described sample preparation methods and the polymerase chain reaction, Toxoplasma gondii DNA was demonstrated in ten of 52 clinical specimens of patients with clinical or serological indications of toxoplasmosis.

Animals↗

PubMed1991

Intestinal microsporidiosis in a German patient with AIDS.

Since intestinal microsporidiosis might be of importance in the pathogenesis of gastrointestinal symptoms in patients infected with HIV, we examined duodenal biopsies of HIV-infected patients by electron microscopy. Enterocytozoon bieneusi infection of the small intestine was found in one of 23 patients studied, which gives a 95% confidence interval for the prevalence rate between 0.1% and 22%. The infected patient was a 24-year-old homosexual male with AIDS who underwent upper endoscopy because of acute epigastric pain, nausea, and vomiting. These symptoms were obviously due to mesenterial Kaposi's sarcoma obstructing the duodenal passage, as was later revealed at autopsy. However, microsporidiosis might have caused the patient's eight-month history of diarrhea and weight loss, since infected cells showed signs of degeneration, and no other pathogens were ever detected in stool or biopsy. Our finding of Enterocytozoon bieneusi infection in a German AIDS patient supports the concept of a worldwide distribution of this parasite; further studies are needed to define its exact prevalence in HIV-infected patients and its pathogenic relevance.

Acquired Immunodeficiency Syndrome↗

PubMed1991

Visceral leishmaniasis mimicking a flare of systemic lupus erythematosus.

Fever in systemic lupus erythematosus (SLE) may be caused by exacerbation of the disease itself or by infection. We report on a patient with a long standing history of SLE that was complicated by fever and pancytopenia with no splenomegaly. SLE disease activity was suspected because of an elevated DNA-antibody titer. The early positive response to corticoid therapy may have masked the underlying infection. Visceral leishmaniasis was diagnosed by a repeated bone marrow biopsy and serological testing.

Animals↗

PubMed1991

Detection of antibody formation in mice, rats and rabbits immunized with different Pneumocystis carinii antigens.

Antibody formation to P. carinii of human origin was determined by an indirect immunofluorescence antibody assay (IFA) after immunization of mice, rats and rabbits with pronase-treated whole cysts and soluble antigen in order to obtain more detailed data about the production of polyclonal antibodies. Antibody titre profiles over defined periods have shown that noticeable differences between the immunoreactions to whole cysts and soluble antigen occur. The soluble antigen produced an earlier and stronger titre rise (peak titres of up to 1:2560 2 to 4 weeks after immunization). In contrast to this, whole cysts produced equally high, although retarded, antibody titre peaks only in normal mice and rats and when the dose had been doubled. Nu/nu mice failed to demonstrate any reaction to these P. carinii immunogens. Cross-reactivity of the antibodies with P. carinii antigen from rat lungs was demonstrated. Possible reasons for different immunoreactions to these antigens, the importance of proteolytic digestion for the results obtained and the potential applicability of these polyclonal antibodies to a histochemical demonstration of the parasite are discussed.

Animals↗

PubMed1991

[Immunohistochemical demonstration of extracerebral toxoplasmosis in AIDS].

Tissue slides obtained at autopsy from 80 cases with AIDS were studied immunhistochemically for infection with Toxoplasma gondii. In 35 cases (43.75%) toxoplasmosis could be found: in 22 cases (27.5%) only cerebral, in 9 cases (11.25%) cerebral and extracerebral and in 4 cases (5%) only extracerebral. Necrotizing lesions, due to the parasite could be seen in brain, heart, lungs, pancreas, adrenal glands and testis, only intracellular trophozoites without tissue damage in GIT, liver, lymphnodes, spleen, prostate, kidney and gl. parotis. The trophozoites and pseudocysts could be clearly demonstrated by immunohistochemistry.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Malaria prophylaxis in travellers to tropical Africa.

This study investigated travellers to tropical Africa with regard to prophylactic treatment of malaria. A total of 5703 travellers completed a questionnaire on their flights back to the Federal Republic of Germany; 4116 passengers (73.7%) had visited East Africa, while 808 (14.5%) had been to West Africa. The results indicate that 90.2% took a regular chemoprophylaxis against malaria. Nevertheless, 8.1% of the travellers used no antimalarials and in 9.3% chemoprophylaxis was inadequate due to inappropriate advice; for example, 7.5% still took pyrimethamine-sulfadoxine as prophylactic. Mefloquine was correctly taken by 38.9% of the travellers in East Africa; 12.6% used it in West Africa where it is not necessary. Antimosquito measures have a high priority for travellers to tropical Africa and dissemination of this fact must be improved since only 72.6% followed through on such advice.

Africa↗

PubMed1990

Prevalence and clinical importance of Entamoeba histolytica in two high-risk groups: travelers returning from the tropics and male homosexuals.

This study was undertaken to learn the prevalence of amebiasis and to assess the clinical importance of Entamoeba histolytica in two high-risk groups: 2700 travelers returning from the tropics and 320 male homosexuals. Some 16.3% of the homosexual men and 4.0% of the travelers had E. histolytica infections. Only five travelers showed a pathogenic zymodeme of E. histolytica, which correlated closely with invasive amebiasis with positive amebic serology and clinical symptoms with diarrhea. The homosexual group had neither a pathogenic isoenzyme pattern nor positive amebic serology. Currently, travelers to the tropics have a risk of 0.3% (1:340) of acquiring invasive amebiasis; 92.5% of all E. histolytica infections in travelers remain asymptomatic and are confirmed by serology and zymodeme status. No homosexual presented with invasive amebiasis.

Adult↗

PubMed1989

Prevalence and control of Schistosoma haematobium infections in the Amran subprovince of the Yemen Arab Republic.

803 schoolchildren in the subprovince of Amran were examined for S. haematobium. The prevalence was 28.9%. Stool samples of 92 children were negative for S. mansoni eggs. Bulinus snails were most frequent, whereas Biomphalaria were rare. Control measures included chemotherapy and mollusciciding. The prevalence in 8 selected villages could be reduced by this from 36.3% down to 5.1%. No gross haematuria and only one single case of heavy infection were detected. Eradication of this disease seems feasible.

Adolescent↗