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F Freymuth

Publications and source records attributed to F Freymuth.

At least 73 records · Page 4Linked to original sources
PubMed1996

[Resistance of cytomegalovirus to ganciclovir: rapid detection of the mutations 460 of the UL97 phosphotransferase].

The substitution of methionine by either isoleucine or valine at residue 460 in the UL97 phosphotransferase has been shown to be responsible for resistance to ganciclovir (GCV) in 30% of resistant cytomegalovirus (CMV) isolates [4]. These substitutions require one nucleotide change in the gene (G- > T 1 380 and A- > G 1378 respectively). The aim of this study was to develop a discriminative PCR assay for rapid detection of these DNA changes. A PCR assay was duplicated in parallel for each mutation; to detect G- > T 1380 each reaction mixture contained primer VSUL14 and either primer LNW to distinguish wild type residues or LNM to distinguish mutant residues, and for A- > G 1378 primers were VSUL8 and either MCMW to detect wild type sequences or MCMM to detect mutated residues. For optimal discrimination, primers MCMW and MCMM were designed with a mismatch at position 3'-1. The reference strains AD169, Davis and Towne, a laboratory GCV-resistant mutant RCL1.7, and 33 CMV isolates (10 resistant, 2 indetermined and 21 sensitive) were tested by PCR. AD169, Davis and Towne, and 30 isolates were amplified only with non modified primers, and the absence of 460 mutations was confirmed by sequencing. Two isolates P1 and P2, from a transplanted patient were amplified with both MCMM and MCMW: sequencing analysis shown the presence of a mixture of strain, one of them harbouring A- > G 1378 mutation. One resistant strain was amplified neither with MCMM nor with MCMW: a C- > T silent mutation at nt 1368 was present. As sequencing analysis confirmed PCR results, discriminative PCR enables isolates to be rapidly assessed for the presence or absence of 460 mutations. Moreover, it can distinguish Met to Val from Met to Ile mutations, and allows the analysis of mixtures of sensitive ad resistant strains.

AIDS-Related Opportunistic Infections↗
PubMed1995

[Quantitative detection of pp65 intraleukocyte cytomegalic antigen in renal transplantation].

OBJECTIVE: To assess the clinical value of quantitative assay of leukocyte cytomegalovirus antigen (LCA) in the management of immunodepressed patients. METHODS: Thirty-three kidney transplant recipients followed a weekly follow-up protocol during the first 3 months after transplantation. LCA was compared with cytomegalovirus (CMV) detection in blood using fibroblast cell culture and with serology tests. LCA was expressed in number of positive cells per 2.10(5) leukocytes, detected by immunofluorescence with a specific monoclonal antibody directed against the pp65 antigen. The standard culture method and a rapid centrifuge method were used for blood samples. The serum level of anti CMV antibodies was determined by ELISA. RESULTS: CMV infection defined as positive viraemia and/or positive serology tests was diagnosed in 22 of the 33 patients. LCA was detected in 20 patients, including all those with clinical signs of infection. Serology was the only method giving a positive diagnosis in 2 patients and was negative in 3 infections positive for LCA. Viraemia was negative in 2 patients positive for LCA. LCA was detected in 60 of the 65 blood samples with a positive viraemia test and in 46 of the 165 negative samples (sensitivity 92% and specificity 72%). Quantitatively, LCA in samples taken from patients with clinical signs was higher than that in samples taken from asymptomatic patients (51 +/- 5 versus 20 +/- 2, p < 0.001). In addition, LCA was detected a mean 7.6 +/- 4 days before significant changes in serology tests, 2.2 +/- 1.6 days before the viraemia and 7.1 +/- 1 days before clinical manifestations. CONCLUSION: Leukocyte cytomegalovirus antigen gives a sensitive means of early positive diagnosis. The quantified level illustrates the patient's risk of infection. This new method is a very helpful tool in following renal transplantation recipients.

Adult↗
PubMed1995

[Quantitative cytomegaloviral leukocytic antigenemia. Clinical aspects].

Cytomegalovirus infection, commonly observed in immunodepressed patients, raises a number of problems both in clinical practice (early rapid diagnosis, therapeutic options) and biological research (resistant strains, mutations). The classical methods of diagnosis do not provide specific information for decision making in each particular clinical situation. We report a case of cytomegalovirus infection in a renal transplant recipient in which quantitative cytomegalovirus antigen level in leukocytes provided rapid early diagnosis of the primary infection and two episodes of recurrent infection. Increase antigen level always preceded clinical manifestations. Three anti-cytomegalovirus regimens were given and the antigen level fell proportionally to clinical improvement. Based on the data in the literature and this clinical observation, it appears that cytomegalovirus antigen level in leukocytes is a precise tool for early diagnosis of cytomegalovirus infection. The technique is rapid, has an excellent sensitivity and the quantitative results are correlated with clinical manifestations. Quantitative anti-cytomegalovirus antigen assay can be a very helpful tool in the management of infected immunodepressed patients.

Antigens, Viral↗
PubMed1995

[Prospective study of neonatal genital mycoplasma colonization and infection].

Genital mycoplasmas have been implicated in different neonatal diseases as pneumonia, sepsis and meningitis. This prospective study was conducted to specify their role in these diseases. POPULATION AND METHODS--A pharyngeal or tracheal swab specimen for mycoplasmas culture was obtained from 100 infants admitted consecutively to the Neonatal Care Unit (NCU) during the first 24 hours of life. Mycoplasma culture of blood and cerebrospinal fluid was also performed. Pharyngeal and/or tracheal specimens were collected again on days 5, 15 and 28 if the child was still in the NCU. Mycoplasma hominis (Mh) and Ureaplasma urealyticum (Uu) were identified by culture in a modified Hayflick's medium. RESULTS--Three-hundred and ten pharyngeal or tracheal swabs were obtained (100 on day 0, 89 on day 5, 72 on day 15 and 49 on day 28). Twenty-one infants had one or more positive swabs in the first five days of life (20 on day 0 and one on day 5); those forming the "Myco+" group and the others forming the "Myco-" group. Uu was isolated alone from 20 infants, associated with Mh from one. Both groups were similar for gestational age, birth weight, maternal fever during labor, prolonged rupture of the fetal membranes or chorioamnionitis and for the incidence of acute respiratory distress. There was a statistically significant difference for the route of delivery (chi 2 < 0.02). One blood culture (from 92 performed) was positive for Uu and another positive for Uu and Mh. Both children were cured without any specific mycoplasmacidal therapy. Three children had probable Uu infection and were also cured without specific therapy. CONCLUSIONS--A pharyngeal colonization with genital mycoplasmas is common in the first days of life (21%) but our data do not allow us to conclude that they are accountable for newborn infections.

Bacteremia↗
PubMed1995

Detection of respiratory syncytial virus by reverse transcription-PCR and hybridization with a DNA enzyme immunoassay.

Nasal aspirates from 238 infants hospitalized with acute respiratory infections during the winter of 1994 and 1995 were tested for respiratory syncytial virus (RSV) by immunofluorescence assay (IFA) and the viral isolation technique (VIT) and by two PCR and hybridization methods: reverse transcription PCR 1 (RT-PCR1), which amplifies the RNAs of all RSV strains, and RT-PCR-2, which allows subgroup classification of RSV. RT-PCR-1 and RT-PCR-2 detected viral sequences in 56.7% (135 of 238) and 48.3% (115 of 238) of the samples, respectively, while only 80 (33.6%) samples were found to be positive by IFA and VIT. Of the PCR-positive specimens, 57 were missed by these routine techniques in RT-PCR-1 and 45 were missed in RT-PCR-2. Although the RSV-PCR-1 and RSV-PCR-2 techniques amplified two different sequences of the RSV genome, they gave similar results for 218 (91.6%) nasal aspirates. Compared with conventional methods, the sensitivity, specificity, and agreement were 97.5, 63.9, and 75.2%, respectively, for RT-PCR-1 and 89.7, 71.9, and 77.7%, respectively, for RT-PCR-2, and for these two RT-PCR assays, the positive predictive value (PPV) and the index of agreement (kappa) were comparable and moderate, respectively: PPV was 57.8% and kappa was 0.52 in RT-PCR-1, and PPV was 60.9% and kappa was 0.54 in RT-PCR-2. However, there was a perfect correlation between the two RT-PCRs, with a PPV of 100% and an excellent index of agreement (kappa = 0.88). Therefore, most RT-PCR results were really true positive, and VIT and IFA, which missed some of them, appeared to be less sensitive.

Base Sequence↗
PubMed1994

[Virological diagnosis and treatment of respiratory syncytial virus infections].

Respiratory syncytial virus infections occur frequently in children, often localized in the upper respiratory tract. Outcome is usually quite satisfactory, but in nearly one half of the infants lower tract involvement may cause severe respiratory insufficiency leading to hospitalization in about 1% of the cases. Its frequency has been estimated at 20 to 30% of the viral infections in hospitalized infants, 10 times the frequency of the other respiratory virus. Respiratory syncytial epidemias last about 4 to 5 months with a seasonal peak in december and january. The direct detection of respiratory syncytial antigens in nasal specimens by immunofluorescence or enzymatic immunoassay is the key to rapid diagnosis. They appear as performant and more convenient than specific IgM antibodies or nucleic acid detections, and than virus isolation on cell culture, which is justified to evaluate strain sensitivity to ribavirin. Immunofluorescence has also been used to identify the subgroups A and B from 1981 to 1993, and respiratory syncytial subgroup A seems to signify more severe disease. Symptomatic assistance may require hydratation, oxygenotherapy and respiratory physical therapy. Antibiotics should not be given as a routine treatment since bacterial superinfection is infrequent, but may be indicated in cases with associated signs of complications. Indications for bronchodilators and corticosteroids are still under debate. Significant results have been obtained with ribavirin and specific anti respiratory syncytial immunoglobulins but further evaluations are still required to precise their use in clinical practice.

Antibodies, Viral↗
PubMed1994

Detection of enteroviruses in cerebrospinal fluids: enzymatic amplification and hybridization with a biotinylated riboprobe.

Cerebrospinal fluids from 54 children with meningitis syndrome were examined for the presence of enteroviruses by cell culture, by enzymatic amplification of viral cDNA and by hybridization. Viral sequences were found in 37/39 CSF specimens positive by cell culture (95%) and in 6/15 (40%) CSF specimens negative by cell culture. Thus, PCR, as a specific and sensitive technique, may be suitable for rapid diagnosis of enteroviral meningitis in clinical specimens from which enteroviruses are difficult to isolate.

Base Sequence↗
PubMed1994

Comparison of nested PCR for detection of DNA in plasma with pp65 leukocytic antigenemia procedure for diagnosis of human cytomegalovirus infection.

A nested PCR was used for the detection of human cytomegalovirus (HCMV) DNA in plasma. The presence of HCMV DNA and its correlation to pp65 leukocytic antigenemia were investigated with 299 blood samples from 45 organ transplant recipients and 63 AIDS patients. Of the 53 samples positive by nested PCR, 52 (98%) were also positive for leukocytic antigenemia and 23 had high levels of antigenemia (> 50 positive cells per 2 x 10(5) leukocytes). Of the 246 samples negative in PCR, only 3 (1.2%) had highly positive antigenemia. For 15 patients having a high antigenemia level in the course of their disease, consecutive blood samples were studied and also assessed for viremia in culture. The extent to which HCMV DNA, detected by PCR, was present in plasma correlated with increased levels of HCMV leukocytic antigenemia for six of the eight AIDS patients and for all the organ transplant recipients. Positivity for HCMV DNA in PCR and for viremia in cell culture was usually restricted to the highest antigenemia levels. From a total of 69 blood samples, PCR and culture gave positive results, respectively, for 17 of 32 samples (53%) and 14 of 32 samples (43%) from transplant recipients and for 15 of 37 samples (40%) and 9 of 37 samples (24%) from AIDS patients. Our findings have shown a strong correlation between high levels of leukocytic antigenemia and HCMV DNA in plasma. The detection of HCMV DNA in plasma by this nested PCR can prove HCMV dissemination in blood, but it lacks the rapidity and simplicity of the leukocytic pp65 antigenemia procedure.

AIDS-Related Opportunistic Infections↗
PubMed1993

Decreased blood TcR gamma delta+ lymphocytes in AIDS and p24-antigenemic HIV-1-infected patients.

The significance of blood TcR gamma delta+ lymphocyte level was evaluated in the context of immunodeficiency and infections in 209 HIV-1-infected patients. Blood TcR gamma delta+ lymphocyte values were found higher in patients belonging to the CDC group II/III than those in the CDC groups IV C1 and IV D (P < 0.001) and P < 0.01, respectively). TcR gamma delta+ lymphocyte counts were lower in patients with oral candidiasis (P < 0.01), and in association with pneumocystosis or toxoplasmosis (P < 0.001). In 81 patients with a detectable HIV-1 p24 antigenemia, TcR gamma delta+ lymphocyte counts were lower than those in nonantigenemic patients (P < 0.001). In the CDC II/III group, p24-antigenemic patients exhibited lower TcR gamma delta+ cell counts than those in patients without antigenemia (P = 0.06). Data suggest that depletion of the TcR gamma delta+ lymphocyte subset characterizes HIV-1-infected patients with oral candidiasis, pneumocystosis, toxoplasmosis, and/or HIV-1-antigenemia.

AIDS-Related Opportunistic Infections↗
PubMed1993

[Prevalence and clinical aspects of A and B subgroups of respiratory syncytial virus infection. Observation of 8 consecutive epidemics between 1982 and 1990].

BACKGROUND: Infants suffering from respiratory syncytial virus (RSV) infection can have severe responses that require intensive care. This study compares the epidemiologic patterns and the severity of respiratory diseases produced by RSV strain subtypes A and B. POPULATION AND METHODS: The prevalence of RSV subgroups was studied over 8 consecutive outbreaks from 1982 to 1990. The files of 73 infants aged from 1 to 24 months admitted because of RSV infection between October 1987 and March 1990 were studied. The criteria of severity were tachypnea and/or the use of the accessory muscles for respiration, apnea and/or cyanosis, hospitalization for > 8 days, hypercapnia and/or acidosis, oxygen therapy, use of corticosteroids and/or bronchodilators, nutritional difficulties. RESULTS: A total of 374 RSV strains were isolated: 142 were group A and were 232 group B. Subtype A predominated during the winter 1987-1988 and subtype B during 1983-1984, 1984-1985 and 1989-1990. Some indicators of severity, such as degree of respiratory distress, duration of hospitalization and levels of oxygen saturation, were correlated with A subgroup infections, but the difference in the severity index for the two subtypes was not statistically significant. CONCLUSIONS: The results are not consistent with other previous reports, perhaps because different indicators of severity were used in this study and infants less than one month old or having other underlying diseases were excluded.

Acute Disease↗