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O Liesenfeld

Publications and source records attributed to O Liesenfeld.

At least 37 records · Page 2Linked to original sources
PubMed1997

Gamma interferon induces Fas-dependent apoptosis of Peyer's patch T cells in mice following peroral infection with Toxoplasma gondii.

Since we previously observed a remarkable decrease in the numbers of T cells in the Peyer's patches of the small intestines in C57BL/6 mice following peroral infection with Toxoplasma gondii, we performed studies to examine the mechanism(s) whereby this decrease in numbers of the T cells occurs. We found that apoptotic cell death of CD4+ and CD8+ alphabeta T cells occurred in Peyer's patches following infection. Upregulation of Fas expression was observed in these T cells. C57BL/6-background mutant mice which lack functional Fas antigen did not develop apoptosis in their Peyer's patches following infection. Treatment of infected C57BL/6 mice with anti-gamma interferon (IFN-gamma) monoclonal antibodies prevented the upregulation of Fas on their Peyer's patch T cells and inhibited the occurrence of apoptosis of these T cells. These results indicate that IFN-gamma induces Fas-dependent apoptosis in CD4+ and CD8+ alphabeta T cells in Peyer's patches in C57BL/6 mice following peroral infection with T. gondii.

Animals↗
PubMed1997

Impaired resistance to the development of toxoplasmic encephalitis in interleukin-6-deficient mice.

The role of interleukin-6 (IL-6) in the pathogenesis of toxoplasmic encephalitis (TE) was examined by using IL-6-targeted mutant (IL-6(-/-)) mice. At 4 and 8 weeks after infection with the ME49 strain of Toxoplasma gondii, significantly greater numbers of T. gondii cysts and areas of inflammation associated with tachyzoites were observed in brains of IL-6(-/-) mice than in those of control mice. Large areas of necrosis were observed only in brains of IL-6(-/-) mice. Tachyzoites were frequently detected in the areas of necrosis, suggesting that necrosis was caused by proliferation of the parasite. These results indicate that IL-6 is protective against development of TE by preventing formation of T. gondii cysts and proliferation of tachyzoites in brains of infected mice. Whereas in brains of control mice, large numbers of inflammatory cells were always observed in areas where tachyzoites were detected, in brains of IL-6(-/-) mice, only small numbers of inflammatory cells were observed in many areas with tachyzoites. Lymphocyte preparations isolated from brains of infected control mice had significantly higher ratios of gamma/delta T cells and CD4+ alpha/beta T cells but lower ratios of CD8+ alpha/beta T cells compared to those of infected IL-6(-/-) mice. There were no differences in the ratios of these T-cell subsets in spleens between these mice. The amounts of mRNA for gamma interferon (IFN-gamma) detected by reverse transcriptase PCR were significantly smaller in brains of IL-6(-/-) mice than in those of control mice, whereas amounts of IL-10 mRNA were greater in the former than in the latter. IL-6 mRNA was detected only in infected control mice. The protective activity of IL-6 against development of TE appears to be through its ability to stimulate IFN-gamma production and induce infiltration and accumulation of different T-cell subsets in brains of infected mice.

Animals↗
PubMed1997

False-positive results in immunoglobulin M (IgM) toxoplasma antibody tests and importance of confirmatory testing: the Platelia Toxo IgM test.

Although tests for detection of immunoglobulin M (IgM) toxoplasma antibodies have been reported to have a high degree of accuracy, it is well recognized by investigators in the United States and Europe that false-positive results may occur with many of these tests, at times to an alarming degree. Unfortunately, this information is not well documented in the literature. Studies on various toxoplasma IgM test kits are frequently flawed. The investigators often use reference tests which have not previously been carefully evaluated as well as sera that were not appropriate to answer the question of how often false-positive results might occur. We recently had the unique opportunity to evaluate the accuracy of the Platelia Toxo IgM test in 575 serum samples obtained during an outbreak of toxoplasmosis which occurred in 1995 in the Capital Regional District of British Columbia, Canada. When compared with results obtained in a reference IgM enzyme-linked immunosorbent assay (ELISA), the Platelia Toxo IgM test had a sensitivity of 99.4%, specificity of 49.2%, positive predictive value of 51.9%, negative predictive value of 99.3%, and an overall agreement of 67.0%. In an attempt to resolve discrepancies between these two tests, a serological profile (Sabin-Feldman dye test, IgA and IgE antibody tests, differential agglutination [AC/HS] test, and IgG avidity method) was performed. Of 153 serum samples that were positive in the Platelia Toxo IgM test and negative in the IgM ELISA, 71 (46.4%) were negative in the Sabin-Feldman dye test. Of the serum samples that were positive in the dye test, 77 (93.9%) had a serological profile most compatible with an infection acquired in the distant past. These results reveal high numbers of false-positive results in the Platelia Toxo IgM test and highlight the importance of appropriate evaluation of commercial tests that are currently being marked. Our results also emphasize the importance of confirmatory testing to determine whether the results of an IgM antibody test reflect the likelihood of a recently acquired infection.

Animals↗
PubMed1997

Comparative evaluation of modified trichrome and Uvitex 2B stains for detection of low numbers of microsporidial spores in stool specimens.

At present, the laboratory diagnosis of intestinal infections caused by microsporidia depends on the detection of the typical spores either with a modified trichrome stain (MTS) or by staining with fluorochromes. The purpose of the present study was (i) to compare staining with MTS (MTS method) and the staining with the fluorochrome Uvitex 2B (U2B method) with respect to their sensitivities and specificities, particularly in the presence of low numbers of spores, and (ii) to evaluate their reliabilities under routine laboratory conditions. First, 30 negative human stool specimens as well as 30 specimens enriched with a low concentration of microsporidial spores were examined. The U2B and MTS methods detected 27 and 30, of the positive samples, respectively (95% confidence intervals for sensitivity, 0.73 to 0.98 for the U2B method and 0.88 to 1.00 for the MTS method) without yielding false-positive results (95% confidence intervals for specificity, 0.88 to 1.00 for the MTS and U2B methods). In addition, analysis of serial dilutions of 17 stool specimens from AIDS patients containing microsporidia revealed comparable detection thresholds (P = 0.52) for both methods. Finally, 40 slides prepared from one stool specimen containing very few microsporidia and 40 negative slides were included in the routine diagnostic program during 1 month in order to monitor laboratory handling and run-to-run variations. Again, both methods exhibited comparable sensitivities (95% confidence intervals, 0.83 to 0.99 for the MTS method and 0.91 to 1.00 for the U2B method) and specificities (95% confidence intervals, 0.91 to 1.00 for the MTS and U2B methods). In conclusion, MTS and U2B methods are equally useful in the diagnosis of microsporidiosis. However, since detection thresholds for both methods differed considerably in all diluted stool specimens, performance of a combination of both methods may be more sensitive than the performance of only one procedure in the event of very low numbers of microsporidial spores.

AIDS-Related Opportunistic Infections↗
PubMed1996

Is the exploding powder gas of the propellant from blank cartridges sterile?

Shots from blank weapons loaded with blank cartridges, when fired from close range or as a contact shot, almost always cause the skin to burst open and lead to injuries to structures below the surface. Subsequently, wound infections are often observed. In addition to the introduction of skin germs, the possibility exists that contaminated propellants may enter into consideration as a source of infection. Using step-by-step experimental procedures we were able to demonstrate that: 1. Blank cartridge propellants were almost always contaminated with Bacillus cereus (nitrocellulose powder more so than black powder); 2. When the shot is fired numerous bacteria survive and are forced out with the gunsmoke from the weapon and thus find their way into the wound. In principle, blank cartridge propellant thus exhibits as much potential for wound infection as the skin germs. Clearly, the species B. cereus is prominent in this context. For open injuries even with 'harmless' blank weapons, an antibiotic prophylaxis should always be administered.

Adult↗
PubMed1996

IL-4 is protective against development of toxoplasmic encephalitis.

IFN-gamma is critical for prevention of development of toxoplasmic encephalitis (TE). Since IL-4 down-regulates production of IFN-gamma, we examined its role in the pathogenesis of TE in IL-4-targeted mutant (IL-4-/-) mice. IL-4-/- mice all died from 6 to 20 wk after peroral infection with cysts of the ME49 strain of Toxoplasma gondii; control mice survived. At 4 and 8 wk after infection, significantly greater numbers of T. gondii cysts and foci of acute inflammation, and greater amounts of tachyzoite-specific mRNA (by reverse-transcriptase PCR) were in brains of IL-4-/- mice than controls. Toxoplasma IgG2b and IgG3 Ab levels were slightly but significantly higher in sera of IL-4-/- than control mice, whereas IgM and IgG2a levels did not differ between these mice. Toxoplasma IgG1 and IgE Abs were not detected in sera of either strain. Amounts of IFN-gamma, TNF-alpha, IL-6, and IL-10 mRNA detected by reverse-transcriptase PCR did not differ between brains of infected IL-4-/- and controls, although brains of the former mice had greater numbers of inflammatory mononuclear cell infiltrates. IL-4 mRNA was detected only in infected control mice. Spleen cells of control mice at 8 wk after infection produced significantly greater amounts of IFN-gamma following stimulation in vitro with soluble T. gondii Ags than did those from IL-4-/- mice. These results indicate that IL-4 is protective against development of TE by preventing formation of T. gondii cysts and proliferation of tachyzoites in the brain. The impaired ability of IL-4-/- mice in the late stage of T. gondii infection to produce IFN-gamma most likely contributes to their susceptibility for development of severe TE.

Animals↗
PubMed1996

Association of CD4+ T cell-dependent, interferon-gamma-mediated necrosis of the small intestine with genetic susceptibility of mice to peroral infection with Toxoplasma gondii.

Since there is a remarkable difference in susceptibility to peroral infection with Toxoplasma gondii among inbred strains of mice, we performed studies to examine the mechanism(s) of this difference in susceptibility. After peroral infection with the ME49 strain of T. gondii, C57BL/6 (B6) mice all died whereas BALB/c mice all survived. At day 7 of infection (when B6 mice began dying), massive necrosis of the villi and mucosal cells in the ilea were observed in B6 but not in BALB/c mice. To analyze the role of T cells in resistance against death and development of necrosis in the ilea after infection, studies were performed using athymic nude and euthymic control B6 and BALB/c mice. Athymic B6 mice all died after infection, but surprisingly, they survived significantly longer than control B6 mice, indicating that T cells predispose to early death in these mice. Necrosis in the ilea was observed in control B6 but not in athymic B6 mice; however, significantly less numbers of tachyzoites were observed in the ilea of the former than the latter mice. These results indicate that necrosis in the ilea of the B6 mice was not due to destruction of tissue by tachyzoites but was mediated by T cells. This deleterious effect of T cells appears to contribute to early death in these mice. In contrast, T cells conferred resistance against death in BALB/c mice but did not cause necrosis in their ilea. To analyze the T cell subset(s) that induces necrosis of the ilea in B6 mice, we examined histological changes of the small intestines after infection of mutant mice deficient in different T cell subsets (with the same H-2b haplotype as B6 mice). Mice deficient in alpha/beta or CD4+ T cells did not develop necrosis in the ilea, whereas wild-type control mice and mice deficient in gamma/delta or CD8+ T cells did, suggesting that the cells that induce necrosis in the ilea after infection are CD4+ alpha/beta T cells. Since interferon (IFN)-gamma has been shown to be critical for survival of BALB/c mice after infection with T. gondii, we examined the role of this cytokine in resistance/susceptibility of infected B6 mice. Treatment of B6 mice with anti-IFN-gamma monoclonal antibody shortly before they developed illness prolonged time to death and prevented necrosis in the ilea in these mice. These results indicate that IFN-gamma mediates necrosis in the ilea of B6 mice after infection. This CD4+ T cell-dependent, IFN-gamma-mediated necrosis of the small intestines appears to be a mechanism that underlies the genetic susceptibility of B6 mice to peroral infection with T. gondii, whereas the same cytokine plays a critical role in the resistance of genetically resistant BALB/c mice.

Administration, Oral↗
PubMed1996

Stool viruses, coinfections, and diarrhea in HIV-infected patients. Berlin Diarrhea/Wasting Syndrome Study Group.

To examine the prevalence of stool viruses and their role in the pathogenesis of diarrhea in HIV infection, we evaluated biopsies and repeated stool samples of 256 HIV-infected patients undergoing diagnostic endoscopy because of diarrhea (n = 136) or other symptoms (n = 120) for bacterial, protozoal, and viral enteropathogens. In 70% of the patients with diarrhea, at least one potential enteropathogen was detected. Stool virus was detected by electron microscopy in 17% (44 of 256), adenovirus in 6.6% (17 of 256), and coronavirus in 11.3% (29 of 256) of the patients. Adenovirus and coronavirus were detected more frequently in patients with diarrhea than in patients without diarrhea [adenovirus 10% (13 of 136) vs. 3.3% (4 of 120), p = 0.0129; coronavirus 15% (21 of 136) vs. 6.6% (8 of 120), p = 0.0142]. Sixty-one percent of patients harboring stool virus were coinfected by another enteropathogen. Pathogens other than stool virus were detected more frequently in patients harboring adenovirus (82%) than in patients without stool virus (48%, p < 0.025). Adenovirus and coronavirus are frequently detected in stools of HIV- infected patients and may contribute to diarrhea. Adenovirus infection may facilitate the occurrence of other intestinal pathogens. Due to frequent coinfections, detection of stool viruses reduces the rate of diarrhea of unknown origin only by approximately 5%.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Study of Abbott Toxo IMx system for detection of immunoglobulin G and immunoglobulin M toxoplasma antibodies: value of confirmatory testing for diagnosis of acute toxoplasmosis.

We compared the Abbott Toxo immunoglobulin G (IgG) and IgM IMx assays with the Sabin-Feldman dye test and an IgM enzyme-linked immunosorbent assay (ELISA) in 398 serum samples previously tested in our laboratory (retrospective group) and 1,000 consecutive serum samples, tested as they were received in our laboratory in 1995 (prospective group). In the retrospective group, the IgG IMx had a sensitivity of 100%, specificity of 99.0%, positive predictive value of 99.0%, negative predictive value of 100%, and overall agreement of 99.5%. The percentages for the IgM IMx were 97.8, 99.0, 98.9, 98, and 98.4%, respectively. In the prospective group, the IgG IMx had a sensitivity of 97.8%, specificity of 98.7%, positive predictive value of 97.8%, negative predictive value of 98.7%, and overall agreement of 98.4%. The percentages for the IgM IMx were 88.3, 95.9, 74.7, 98.3, and 95%. A serological profile (IgA and IgE antibodies and the differential agglutination [AC/HS] test) was performed in an attempt to resolve discrepancies. Of 21 serum samples that were positive in the IgM IMx and negative in the IgM ELISA, 19 had serological profiles which were most compatible with an infection acquired in the distant past. Of 8 serum samples which were positive in the IgM ELISA and negative in the IgM IMx, 5 had serological profiles which were most compatible with an infection acquired in the distant past. Of the 55 serum samples that were positive in both IgM tests, 21 were from patients who had serological profiles which were most compatible with an infection acquired in the distal past. In conclusion, our data highlight the importance of confirmatory testing for the diagnosis of recently acquired infection with Toxoplasma gondii. When compared with the dye test and IgM ELISA, the Toxo IgG and IgM IMx assays, respectively, revealed high overall agreement in the retrospective and prospective study.

Acute Disease↗
PubMed1995

Culture of intestinal biopsy specimens and stool culture for detection of bacterial enteropathogens in patients infected with human immunodeficiency virus. The Berlin Diarrhea/Wasting Syndrome Study Group.

The diagnostic yields of stool cultures and biopsy specimens for the detection of enteric bacterial pathogens in 213 human immunodeficiency virus-infected patients were compared. Forty-five percent (19 of 42) of the pathogens were detected exclusively by stool culture, 2% (1 of 42) of the isolates were detected exclusively by culture of biopsy specimens, and 53% (22 of 42) were detected by both methods. Repeated stool cultures remain the most important means of diagnosing enteric bacterial pathogens, which were encountered in 20% (40 of 213) of all patients. The additional culture of biopsy specimens should be reserved for patients with suspected mycobacteriosis.

AIDS-Related Opportunistic Infections↗
PubMed1994

[Imported cholera infection caused by a new nonagglutinating cholera agent].

Within 24 hours of returning from a five-week holiday in Pakistan a 15-year-old girl developed vomiting and massive diarrhoea leading to severe dehydration with hypovolaemic shock. The diastolic blood pressure was no longer measurable and prerenal renal failure occurred with a serum creatinine of 4.4 mg/dl and metabolic acidosis (pH 7.21, base excess-16.9 mmol). Initially treatment consisted of rehydration (day 1: 9280 ml, day 2: 4850 ml). The patient's condition rapidly improved and she had voluminous stools. A concurrent urinary infection due to Klebsiella pneumoniae was first treated with cotrimoxazole. As a new strain of Vibrio cholerae, serogroup O 139, was isolated from stool, treatment was changed to tetracycline (50 mg/kg daily). Regaining a good general state she was transferred to an isolation ward on the 6th hospital day. The isolated cholera organism belongs to a nonagglutinating serogroup which is indistinguishable clinically and epidemiologically from the classical Vibrio strains which cause cholera. Since the end of 1992 this new serogroup has been causing an explosive spread of cholera in Bangladesh and India.

Adolescent↗
PubMed1994

A case of disseminated toxoplasmosis-value of PCR for the diagnosis.

Extracerebral toxoplasmosis has recently gained greater attention as a consequence of the AIDS epidemic. Serological techniques are unreliable, while isolation of the parasite is either time-consuming or insensitive. We here report a case of disseminated toxoplasmosis in a patient with AIDS. Diagnosis was suggested by serological tests and confirmed by PCR and Southern blot hybridisation or nested PCR. Detection of specific DNA was feasible in bronchoalveolar fluid, blood, serum and tissue samples. Direct detection of parasite-specific DNA by PCR and by nested PCR proved to be a promising, sensitive and rapid method for the diagnosis of disseminated toxoplasmosis, enabling us to promptly initiate specific treatment.

AIDS-Related Opportunistic Infections↗
PubMed1993

[A Q fever epidemic in Berlin. The epidemiological and clinical aspects].

An epidemic of Q fever in Berlin affected at least 80 patients (45 females, 35 males; age range 1-75 years). Sheep were identified as the focus of infection: they had been brought to a veterinary clinic because of nonspecific symptoms. The peak incidence of the infection was in April and May, 1992. Most of the patients were staff or students at the veterinary clinic. This is the most northern and, at the same time largest, Q fever epidemic recorded in Germany over the last 28 years. The complement fixation reaction (CFR) was not helpful diagnostically in the acute stage of the disease as it remained negative in the first 14 days (CFR < or = 1:5). Most of the patients had sudden fever to over 40 degrees C, severe headache and dry cough. Pulmonary infiltrates were seen in the chest radiograph of 8 of the 10 patients presented in this contribution. Auscultation was largely negative. Two patients had signs of hepatic involvement (GPT as high as 71 U/l). The drug of choice was doxycycline at a dosage of 200 mg twice daily for 14 days.

Adolescent↗
PubMed1989

Does routine screening for benzodiazepines help to diagnose dependence in psychiatric inpatients?

After admission, 899 inpatients of a psychiatric university hospital were routinely screened for benzodiazepines (BDZ) in the urine. BDZ were detected in 134 (15%) patients with various primary diagnoses. Criteria for BDZ abuse or dependence were found in 36 patients. In 35 cases, either intake of BDZ had not been reported in the first psychiatric interview, or such a report had not been documented in the patient's charts. None of these 35 patients was found to have BDZ abuse or dependence. Psychiatric inpatients with BDZ abuse or dependence seem to report their intake of BDZ. These findings suggest that a routine screening for BDZ can hardly help to diagnose dependence within a university hospital setting. Nevertheless, an objective test for intake of BDZ may be useful in special cases.

Anti-Anxiety Agents↗
PubMedDate not supplied

Three-year prevalence of enteropathogenic bacteria in an urban patient population in Germany.

The prevalence of enteropathogenic bacteria over a three-year period was 3.1% in an urban population in Germany. Nontyphoidal Salmonella spp. (1.8% prevalence) represented 59.3% of all positive isolates, followed by Campylobacter spp., which constituted 22.1% of such isolates. Clostridium difficile toxin was detected in 5.6% of samples submitted specifically for detection of cytotoxigenic C. difficile. The seasonal distribution showed an increase of Salmonella, Shigella and Aeromonas/Plesiomonas isolates in the post-holiday season, partly due to returning travelers. An epidemic five-fold increase of Salmonella enteritidis isolates was found over the three-year-period. Enteropathogenic bacteria such as Salmonella, Campylobacter and cytotoxigenic C. difficile were common etiologic agents of gastrointestinal tract infections in patients with AIDS. We conclude that travelers and HIV-infected subjects are especially prone to infection with enteropathogenic bacteria; preventive measures to control the Salmonella enteritidis epidemic are essential.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Detection of Clostridium difficile toxin by enzyme immunoassay, tissue culture test and culture.

Clostridium difficile toxin is frequently encountered in patients with antibiotic-associated diarrhea. A commercially available enzyme immunoassay (EIA) detecting toxins A and B was evaluated, screening 148 stool specimens specifically submitted for the detection of C. difficile. A sensitivity of 100% and a specificity of 97.5% were found compared to a tissue culture assay. The overall prevalence of C. difficile toxin was 22.1%. Cephalosporins had been administered significantly more often to toxin-positive patients. The EIA proved to be a suitable test for the detection of C. difficile toxin, revealing high prevalences in specifically submitted clinical specimens.

Bacterial Proteins↗
PubMedDate not supplied

[Imported visceral leishmaniasis (kala azar) in a German infant].

We here report the case of a 1 4/12 year old girl with visceral leishmaniasis. Returning from a trip to Mallorca she presented with pancytopenia, splenomegaly and fever and was admitted to hospital with suspected malignancy. Diagnosis was established microscopically from bone marrow smear and confirmed by PCR-assisted amplification of leishmania-specific DNA from peripheral blood. Treatment was conducted with stibogluconate for 25 days. Defervescence and improvement of clinical symptoms was seen after 4 days of treatment. Infection due to Leishmania donovani can be acquired throughout the entire mediterranean area and should therefore be included in the differential diagnosis of suspected malignancies in patients with a history of travel to mediterranean countries. PCR proved to be a sensitive tool for establishing the diagnosis of visceral leishmaniasis.

Antimony Sodium Gluconate↗