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C Apetrei

Publications and source records attributed to C Apetrei.

At least 37 records · Page 2Linked to original sources
PubMed1998

Human immunodeficiency virus type 1 subtype F reverse transcriptase sequence and drug susceptibility.

We sequenced and phylogenetically analyzed the reverse transcriptase (RT) regions of the pol genes of 14 human immunodeficiency virus type 1 (HIV-1) isolates from Romanian patients, which were classified as subtype F on the basis of env gene structure. The RT sequences showed that the strains clustered phylogenetically and were equidistant from other HIV-1 subtypes as shown by the neighbor-joining and maximum-likelihood methods, allowing us to define HIV-1 subtype F according to the pol classification. The subtype F RT sequences differed from reported group M RT sequences by 10.94% (for nucleotides) and 7.6% (for amino acids). Phenotypic analysis of subtype F susceptibility to three classes of antiretroviral compounds showed an increase in the 50% inhibitory concentration of the tetrahydroimidazo[4,5,1-jk] [1,4]-benzodiazepin-2-(1H)-one and -thione (TIBO) derivate R82913 for one strain which was naturally resistant to this compound. This first report of subtype F pol sequences confirms the perfect correlation between the phylogenetic positions determined by env and pol analyses and suggests that virus variability might influence the efficacy of antiretroviral treatments. This finding warrants a global evaluation of the phenotypic and genotypic susceptibility of HIV-1 subtypes to antiretroviral drugs.

Adult↗
PubMed1997

Synthetic peptide ELISAs for detection of and discrimination between group M and group O HIV type 1 infection.

We developed and evaluated two peptide-based immunoassays to confirm and discriminate between group M and group O HIV-1 infection. These assays are based on in vitro competition for antibody binding between M and O peptides. The first EIA is based on competition between group M and group O gp41 immunodominant domains and the second on competition between group O and group M V3 regions of gp120. Two panels of sera were used: the first consisted of 109 sera collected from 27 group O- and 92 group M-infected patients in whom the HIV isolates had been genotyped by sequencing or heteroduplex mobility assay. In this panel, the combination of the two assays correctly discriminated 106 samples (100% group O and 96.7% group M samples). The second panel, used for the field evaluation of the two assays, consisted of 157 samples from HIV-1-infected Cameroonian patients, 33 strains having been genotyped. The combination of the two techniques in a serogrouping algorithm discriminated 147 of these samples, 74 being HIV-1 group O and 73 group M. These results always correlated with genotyping results. The 10 sera that were not successfully classified by these assays were from early seroconverters. Altogether, the two assays clearly differentiated 263 of 276 (94.9%) samples in the two panels. On the basis of the genotyping results, the positive predictive value for group discrimination in the two panels was 100% for both GSEIA assays. Our peptide-blocking group-specific EIAs for differentiation and confirmation of HIV-1 group M and group O infection are complementary tools for epidemiological studies and surveillance of HIV-1 group O strain trafficking.

Amino Acid Sequence↗
PubMed1997

Susceptibility of human immunodeficiency virus type 1 group O isolates to antiretroviral agents: in vitro phenotypic and genotypic analyses.

We investigated the phenotypic and genotypic susceptibility of 11 human immunodeficiency virus type 1 (HIV-1) group O strains to nucleoside and nonnucleoside reverse transcriptase (RT) inhibitors and protease inhibitors in vitro. Phenotypic susceptibility was determined by using a standardized in vitro assay of RT inhibition, taking into account the replication kinetics of each strain. HIV-1 group M and HIV-2 isolates were used as references. DNA from cocultured peripheral blood mononuclear cells was amplified by using pol-specific group O primers and cloned for sequencing. Group O isolates were highly sensitive to nucleoside inhibitors, but six isolates were naturally highly resistant to all of the nonnucleoside RT inhibitors tested. Phylogenetic analysis of the pol gene showed that these isolates formed a separate cluster within group O, and genotypic analysis revealed a tyrosine-to-cysteine substitution at residue 181. Differences in susceptibility to saquinavir and ritonavir (RTV) were not significant between group O and group M isolates, although the 50% inhibitory concentration of RTV for group O isolates was higher than that for the HIV-1 subtype B strains. The study of HIV-1 group O susceptibility to antiretroviral drugs revealed that the viruses tested had specific phenotypic characteristics contrasting with the group M phenotypic expression.

Amino Acid Sequence↗
PubMed1996

Lack of screening test sensitivity during HIV-1 non-subtype B seroconversions.

OBJECTIVE: To evaluate the serological consequences of HIV-1 group M diversity we studied the ability of screening tests to detect anti-HIV antibodies in early seroconverters infected by different HIV subtypes. SETTING: Virology Department, Bichat-Claude Bernard Hospital, Paris, France. DESIGN AND METHODS: Symptomatic patients with serial samples and with infective strains characterized by heteroduplex mobility assay. In each case, two sera were selected. The first (pre-seroconversion sample) was the last p24 antigen-positive/Western blot-non-reactive sample. The second (seroconversion sample) was the first Western blot-reactive sample. One second-generation enzyme immunoassay (EIA; Abbott) based on anti-human immunoglobulin (Ig) G-conjugate and three third generation EIA (Abbott; Enzygnost; Genscreen) based on the double antigen sandwich principle, detecting IgM and IgG, were used. RESULTS: Ten patients had subtype B strains and nine had non-B strains (seven were A, one E and one G). The Abbott third-generation test was more sensitive than the second generation test for pre-seroconversion subtype B samples (nine versus four out of 10; P < 0.05), but not for non-B subtypes; only two of the nine non-B sera tested were positive by both EIA. Positivity rates and optical densities differed (P < 0.05) between B and non-B subtypes in all third-generation EIA. There was no significant difference between the subtype B and non-B groups with regard to the interval between the pre-seroconversion sample and the seroconversion sample (subtype B, 6.7 +/- 2.6 days; non-B, 5.2 +/- 1.7 days). No significant difference in positivity rates and optical densities were found between B and non-B subtypes in these seroconversion samples. CONCLUSION: The shorter time since HIV infection required for sera to become reactive in third-generation EIA screening tests is due to better sensitivity for subtype B strains only. These results stress the importance of strict donor selection, the need to test screening kits against large panels of all subtypes, and the place of p24 antigen testing in closing the window of seroconversion.

Antibodies, Viral↗
PubMedDate not supplied

[The rejection of a hepatic graft].

Hepatic graft rejection is an epiphenomenon of liver transplantation. Despite the immunosuppressive therapy, nowadays a level of 30-50% of acute rejection and 5-15% chronic rejection is always persisting. Graft rejection prophylaxis essentially represents the result of a subtle equilibrium of the chronic immunosuppression. This study presents the essential data concerning the graft rejection, such as: prevalences, classifications, clinical presentation and diagnostic, both anatomopathological and differential. Modern therapy of hepatic graft rejection is also presented.

Acute Disease↗
PubMedDate not supplied

[The evaluation of noninvasive samples for detecting anti-cytomegalovirus IgG antibodies].

Patients admitted in dialysis centers are at greatest risk to achieve blood-borne infections. One of the most frequent is the cytomegalovirus infection, acquired from transfused blood products. The aim of our study was to determine the prevalence of IgG anti-CMV in patients on dialysis at the "C. I. Parhon" Hospital from Iaşi (Romania). In addition, the role of non-invasive samples (saliva and capillary blood) for such epidemiological studies was determined. ELISA Wellcome anti-CMV IgG was used for identification of specific antibodies in serum, capillary blood, saliva. The prevalence of anti-CMV IgG in the group of study was higher than that established in general populations and 79.06% saliva specimens and 93.76% of capillary blood samples were positive. To establish the specificity, sensitivity and predictive values of Wellcome anti-CMV when non-invasive samples are used, we compared the results obtained by testing saliva and capillary blood to those obtained by testing serum. We may conclude that the non-invasive samples are useful for CMV-infection surveillance in risk groups.

Adult↗
PubMedDate not supplied

[The clinical and immunological correlations between the p24 antigenemia levels and those of anti-p24 antibodies in HIV-seropositive children].

The influence of HIV I p24 antigen immune complexing with anti-p24 antibodies of the assessment of their respective levels in HIV-positive sera was studied. ELISA tests were used for evaluating anti-p24 and p24 antigenemia, with or without acid dissociation. We have observed that: 1. p24 antigenemia usually coexisted with low anti-p24 levels, an inverse correlation between these two parameters being traced; acid dissociation increased the percentage of p24 positive sera, especially when anti-p24 titers are low; 2. on contrary, after acid dissociation, p24 Ag remain undetectable in 55.56% of patients presenting high titers and 29.41% of those with low levels of anti-p24; acid dissociation do not increase anti-p24 titers. Whereas the first group of observations suggests that p24 Ag and anti-p24 Ab may be involved in immune complexes, the second set indicates that p24 Ag and Ab were not inevitably linked in such complexes. So, they may be indicative for two distinct biological phenomena.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

[Epidemiological observations on the evolution of influenza in the city of Iaşi in the epidemic season of 1993-1994].

The epidemiological, clinical and laboratory data of influenza and other respiratory diseases recorded during the epidemic season 1993-1994, as they resulted from the comparative analysis of the cases reported weekly and those recorded through the "sentinel" collectivities method, are presented. The findings at admissions to the Infectious Diseases Hospital, Military Hospital, Diagnosis and Treatment Centre for Pupils and Students and the solicitation for medical care at the Emergency Ambulance Service were also interpreted. The involvement of A/Beijing/32/92/(H3N2) influenza virus was confirmed by evidencing the seroconversion on two serum samples tested through RIH, while for others antigens anamnestic reactions were recorded. The influenza epidemic had affected all age groups, with horizontal extension, a first rise in December 1993 followed by the decline determined by winter vacation being notice. A second epidemic rise, much stronger, started beginning with the last month of January and reached a peak at mid February, followed by a marked decline.

Acute Disease↗
PubMedDate not supplied

[The presence in pregnant women of the risk factor of serum antibodies against 9 viruses with significance in materno-infantile pathology and the transfer of these antibodies to the newborns].

Indirect enzyme immunoassay, performed with Labsystems (Helsinki) kits, in 30 mothers and their newborns, revealed that 100% of parturient women present IgG antibody to hepatitis A (HAV), herpes simplex 1, and measles viruses, constantly transferring these antibodies to their newborns. 78.6% of the women had IgG to rubella (German measles) virus, passively transmitting them to their offsprings. Serological markers (HBsAg and anti-HBc) of hepatitis B virus infection were present in 42% of the investigated women, anti-HBc being also present in the serum of the newborns. Between the identified risk factors (in the past obstetrical history, current pregnancy, labor and early postnatal period) and the spectrum of IgG antibodies present in mothers no significant correlations were revealed. The same obvious lack of correlation between IgG antibodies and risk factors in the neonate (prematurity, low birth weight, malformations) was also found. However, the presence of IgG anti-measles (2 case), IgM anti-rubella (1 case) and IgM and HAV (4 cases) was associated, in the same order, with interstitial pneumonia, hepatosplenomegaly and death, icterus neonatorum, cardiovascular and neurologic malformations. Neither mothers nor their offsprings presented anti-HIV antibodies, suggesting that in the investigated patients no perinatal transmission had occurred.

Adult↗
PubMedDate not supplied

[Seroepidemiological data on the circulation of influenza virus in Moldova in 1991-1992].

OBJECTIVES: 1. To establish the predominant circulating antigenic subtypes of influenza viruses in the epidemic season (19911992). 2. To evaluate the efficiency of seroepidemiological method in determining the circulating antigenic subtypes and its practical consequences. METHODS: Our study consist of 1082 patients with acute respiratory disease or their contacts. Antigens prepared at "Cantacuzino Institute", C.D.C. Atlanta and from viral strains isolated in our laboratory were used. Hemagglutination-inhibiting Test was preceded by the elimination of the unspecific inhibitors with IO4K M/90. Significant titers were considered those > 1/10. RESULTS: Were assessed by determining the number of antibody carriers, their ratio and geometrical mean of the reciprocal value of H.I. antibody titers. CONCLUSIONS: 1. In the winter of 1991 and 1992 A/H3N2 infections and in the spring 1991 and 1992 A/H1N1 virus prevailed, while B virus circulated by the end of spring 1992 epidemic season. 2. The decrease in 1992 of A/Iaşi/1/69 (H3N2) activity at the same time with high titers against A/Iaşi/1/76 (H3N2) and A/Iaşi/1/80 (H3N2) suggests a marked antigenic drift occurring in this interval 3. Serological method for determining the presence of hemagglutination inhibiting antibodies seemed enough and compulsory for detecting the etiological agent of acute respiratory disease, and an epidemic outbreak. 4. The circulation of three distinct antigenic subtypes determines the options for composition of anti-influenza vaccine.

Adolescent↗
PubMedDate not supplied

[The specific serological profile in hepatitis B virus infection in children].

UNLABELLED: Hepatitis B virus infection (HBV) has a very well known specific serologic profile. In the last years the molecular biology methods reveal some "particular serological profiles" by genomic mutation. One particular profile consists in the absence of anti-HBc total antibodies simultaneously with the presence of HBsAg. Our tested group consists of 372 children aged 0.1 to 15 years. The presence of HBsAg was determined by ELISA "sandwich" and confirmed by neutralisation test. For HIV infection we used two ELISA tests (competitive and indirect) and the Western Blot test for confirmation. Of the total, there were 13 children HBsAg positive and without anti-HBc antibody (3.49% respectively), 7 of the 13 children (53.8%) were dystrophic and 4 were HIV positive (30.76%). From 372 cases, 104 were HBsAg positive (27.9%) and 53 (14.2%) of them had chronic hepatitis. CONCLUSIONS: 1. The particular serologic profile requires the testing of all serological markers specific for HBV. 2. This particular serologic profile is correlated with HIV positive status and dystrophy.

Adolescent↗