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Biomedical subjects

C Cernescu

Publications and source records attributed to C Cernescu.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

Ex vivo differentiation of umbilical cord blood progenitor cells in the presence of placental conditioned medium.

Hematopoetic stem cells (HSC) are the progenitors for the lympho-hematopoietic system, with long lifespan and high proliferation potential. Transplantation of HSC from bone marrow or peripheral blood represents a standard therapy in severe hematological conditions. A possible alternative source of HSC is the umbilical cord blood, prepared by various separation procedures followed by expansion in cultures supplemented with hematopoietic growth factors. In order to check the effects of placental conditioned medium (PCM) from placental cells culture upon viability of HSC, we added plasma, PCM, dimetil sulfoxyde or hemin in HSC cultures. Flow cytometry or direct scoring of solid cultures using CD45+, CD34+, CD71+ and CD14+ fluorescent-labeled monoclonal antibodies evaluated the effects upon cell proliferation and colony forming ability of HSC cultures, versus controls. PCM produced the highest proliferation, followed by plasma, DMSO and hemin. PCM improved the survival time and maintained a higher proportion of immature cells. PCM stimulates the differentiation towards myeloid lineage progenitor cells (>90% being CD45+), increasing the percentage of CD14+, granulocites /monocytes precursors. It is highly suggestive that PCM contains growth factors or cytokines, which regulate the development of HSC. Characterization of these factors is in progress.

Cell Differentiation↗
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The development of larger cells that spontaneously escape senescence--a step during the immortalization of a human cancer cell line.

There are few information concerning the changes associated with the transition interval when slow growing, primary explanted human cancer cells are displaced by new selected faster growing cells and became an immortal cell line. In a previous paper (J. Cell. Mol. Med., 5: 49-59, 2001) we described the TV cell line derived from a laryngeal tumor which harbors human papillomavirus (HPV) gene sequences throughout more than sixty in vitro passages. In this paper we analyze the modifications observed during the crisis interval when significant amount of cells senesce but occasional cells acquire some mutations that make them immortal. Confocal microscopy analysis revealed the heterogeneity of the cells in terms of their size and nucleus/cell ratio. Proliferation capacity was assessed by flow cytometry analyzing DNA content and expression of transferrin receptor (CD71). We discussed the possibility that HPV genome sequences alleviate a proliferation block during the crisis growth arrest of human larynx carcinoma cell line and the possibility that the cells monitor their size and growth by measuring the levels of some protein whose synthesis is coupled to cell development.

Antigens, CD↗
PubMedDate not supplied

The comparison of different protocols for expansion of umbilical-cord blood hematopoietic stem cells.

Hematopoiesis is maintained by the activity of multipotent stem cells, which have the dual capacity to self-renew and to differentiate into all of the blood cell lineages. The major challenge of stem cells based regenerative therapy is to expand ex vivo the primitive compartment to increase transplantable stem cells number. The present study was designed to evaluate several culture systems for in vitro maintenance of umbilical cord blood stem cells. The influences of different growth conditions such as stromal feeder layer, cytokines supplement and placental conditioned medium (PCM) have been evaluated over a relatively short period of time on CD34(+) cell expansion and maintenance of clonogenic progenitors. When cells were expanded on feeder layer in the presence of added cytokines and PCM on average a 2.96-fold increase of CD34(+)CD71(-) and a 3.13-fold increase of CD34(+)HLA-DR(-) was observed. The total number of colony forming cells (35 +/- 2.65) indicated also that the yield of clonogenic progenitors obtained with a combination of all factors was two folds higher than each of these factors alone and ten time above control (3.67 +/- 2.52). In conclusion, the results of our study clearly show that the ex vivo expansion of hematopoietic progenitor cells obtained from human umbilical cord blood is dependent on controlled experimental conditions, which might be helpful when designing culture systems for clinical applications.

Antigens, CD34↗
PubMedDate not supplied

"Trial moves rapidly on, when the judge has determined the sentence beforehand" (W. Scott: Ivanhoe, 36) or pitfalls in serosurvey of anti-hepatitis C antibody in children.

Hepatitis C is and will be a major public health concern. Confirmed infections were reported from all Romanian counties but important differences between regions raise several explanations. Differences may reflect the different levels of testing, the performances of laboratories in confirming initially reactive samples or the risk factors higher prevalence. We have suggested that the prevalence of anti HCV infections can be a surrogate marker for the quality of parenteral medical or paramedical interventions. Present report identified additional problems in the surveillance of HCV infection in children. We screened 1787 samples from children hosted in orphanages (children under three years old) or in preschool children institutions (between 3-7 years old). We detected 31 repeatedly reactive samples with two EIA screening kits but confirmed only 8 in WB anti HCV. Four confirmed samples come from children under four months old suggesting maternally transmitted antibodies. In highly endemic area, many infants have maternally derived antibodies and the wane of reactivity comes with age above 12 months. Therefore, the prevalence of anti HCV antibody in infants reflects the prevalence in adult population. Confirmatory tests are mandatory for the serosurvey in children. More frequent than adults samples, children EIA reactive samples give indeterminate or negative Western Blot profiles. Only the viral load evaluation can confirm those samples as false positive or, on the contrary, samples at the beginning of seroconversion.

Child↗
PubMedDate not supplied

Assessment of the anti-hepatitis B vaccination efficacy in high risk children.

In October 1995, The Ministry of Health has initiated the national immunization program of newborns against hepatitis B. Owing to the frequency of asymptomatic Hepatitis B clinical forms in children, as well as the deficiencies in the surveillance system, the assessment of the vaccination efficacy can be performed objectively only by the detection of the prevalence of anti HBs antibodies in children to whom the complete three doses of immunization schedule have been administered (at 0, 2 and 6 months of age). We report in this study the results of a seroprevalence research carried out on a group of 272 children from orphanages who have been vaccinated. A protective anti HBs titer (> 10 mIU) was recorded only in 66.3% of cases; other 10 samples contained antibodies at a titer lower than the protective level. In the 80 children without seroconversion the presence of anti HBc antibodies (marker for the natural infection) was investigated. 30% of the seronegative children have anti HBc antibodies from which 54.2% have also HbsAg. Significant differences were recorded in the seroconversion level and in the geometric mean of titers between the various units in which sera were collected. In four orphanages (district Arad, Jassy, Sibiu and Teleorman) the seroconversion exceeded 90%, in 5 orphanages it was over 80% and in the others it ranged from 30% to 70%. The lowest seroconversions were recorded in the orphanages in Bucharest, Botoşani, Galaţi and Olt. The possible causes of the low immunogenicity are analyzed: non-vaccination or incomplete vaccination; low immunoreactivity of children, many of whom are premature; high HbsAg carriage rate among the mother's etc. Although the evolution of the post vaccinal seroconversion is not a routine practice in the appraisement of Hepatitis B vaccine immunogenicity, our results require the extension of the study in order to adopt the most effective vaccinal strategy.

Hepatitis B↗
PubMedDate not supplied

Low rates of seroconversion after hepatitis B vaccination in orphanges with high prevalence of virus carriers.

A serosurvey of Hepatitis B infection markers was conducted in two orphanages that adhered to Hepatitis B vaccination policy. In spite of comparable sizes (80-90 children per facility), housing conditions and infection control practices, the level of HbsAg endemicity was different in each unit in direct relation with the mean age of the children. The prevalence of HbsAg carriers and the interval spent in collectivity strongly affect the seroconversion rate after HB vaccination. Other elements that can explain the low seroconversion rate were: the proportion on fully vaccinated children, the number of vaccine administered doses and the delayed age at which childhood immunization schedule was initiated. In order to increase the protective antibody response, booster doses were administered to a limited number of nonseroconvertors or to children with a nonprotective level of anti-HBs antibody (< 10 UI). This intervention provides evidence of prompt rising in antibody titers, comparable with titers found in children with wild infection.

Carrier State↗
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Romanian HIV-AIDS epidemic after a decade of evolution.

Situated in Southeastern Europe, with a surface of 237,500 km2 and a population of over 22 million, Romania was a special case in the evolution of global AIDS crisis. After the first reported case in a homosexual male in 1985, five years elapsed till the epidemiological investigations done in the Institute of Virology, Bucharest (1-4) provided strong evidence for what may represent the world's largest iatrogenic transmission of blood-borne pathogens in children. On the basis of Epidemiological Fact Sheet concerning Romania provided by UNAIDS/WHO Working Group on Global HIV/AIDS and STD Surveillance we offer a couple of graphics which are considered important for informed decision-making and planning at national and regional levels. We emphasize the lack of availability of many specific data both on epidemiological and socio-behavioral indicators. Structural collapse in Eastern Europe sets the scene for the rapid spread of HIV/AIDS among young people and the lack of information may contribute to an unexpected rebound of the epidemic.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

An outbreak of aseptic meningitis due to ECHO 30 virus in Romania during the 1999 summer.

Between April-September 1999 an unusually high number of acute aseptic meningitis was reported in six North Eastern counties of Romania. At the end of 1999 summer the epidemic area extended in South Romania including the Capital City Bucharest. The total number of cases surpassed 5500. The majority of confirmed cases were young children under 15 years of age. More than 1800 cases were registered in the same interval in the neighboring Republic of Moldavia. We report the isolation of ECHO 30 virus from 12 CSF samples of 52 tested on RD and human diploid cells. A small case control study identified high seroneutralization titers confirming a recent ECHO 30 infection in 74% of patient's samples and in 54% of samples from control children tested. The time spent outdoors and poor hygiene practices were prominent risk factors for transmission.

AIDS-Related Opportunistic Infections↗
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The evolution of hepatitis B virus infection in children with symptomatic AIDS.

Hepatitis B virus (HBV) markers were determined in 80 children under 5 years of age with HIV symptomatic infection. Because of high carrier rate of hepatitis B virus in Romania we investigated as control a group of age matched 36 HIV negative children offsprings of HBsAg carrier mothers. Serological and epidemiological investigations in families of HIV infected children support horizontal nosocomial and not vertical transmission for HIV in contrast with HBV whose perinatal transmission can not be excluded. Concerning the probable route of HBV infection both groups of children seem to have a comparable risk for parenteral, contact-associated or maternal-neonatal transmission. HBsAg was detected in 76.25% HIV positive subjects and in 13.9% of control (P = 0.05). From all serum samples tested, only 12, all from the control group, did not present any markers of past or current HBV infection. Two serum markers have been used as an index of active HBV replication: HBe antigen detection and HBs antigen quantification in one or paired serum specimens. HBeAg was detectable in 20% of HIV infected children and only in 2.8% controls (P = 0.05). Almost all HBeAg positive patients have higher values for HBs antigenemia. HBsAg concentrations well above the assay cut off value (sample/cut off ratio > 15) were generally representative for HIV infected children (54% versus 5.6% in controls). The prevalence of hepatitis Delta markers and anti-HCV antibodies was not significantly higher in HIV infected children in spite of the fact that they are potentially exposed to a wider range of antigens.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Biological roles of HIV Nef proteins. A minireview.

The nef gene, its protein products and diverse mechanisms by which HIV pathogenicity is nef-mediated in vivo and in vitro explain the huge amount of works on this topic. Until now the following functional roles have been assigned for nef: 1. downregulation of virus replication; 2. GTP binding and GTPase activities; 3. modulation of cytoplasmic signalling; and 4. cellular (CD4 and IL-2) gene regulation. Many reports which demonstrate the possible functions of nef in viral replication and in development of AIDS have been refuted by other scientists who failed to confirm some biological activities. Host immune response against nef proteins has been claimed as an early diagnosis marker or to be involved in disease progression. Also, nef proteins have been involved in blocking of HLA antigens, in superantigen production or in crossreactivity with some cellular antigens. The role of nef is a complex one, important in establishing and maintaining viral latency in vivo and regulating virus replication in vitro.

Down-Regulation↗
PubMedDate not supplied

[Importance of the virology laboratory in the diagnosis of virus diseases].

Introduction. Principles of the Modern Diagnosis in Virology--isolation of the causative agent;--histologic and electronoptical diagnosis;--serologic. Efficiency of the viral diagnosis. Modern and Rapid Diagnostic Methods--progress in the technology of cell cultures and immunofluorescence;--new serologic methods.

Humans↗
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HCV seroprevalence in dialysis patients, their relatives and medical staff.

HCV infection has emerged as a significant problem for both dialysis patients and medical staff. We report the data found in a dialysis center in Bucharest for hepatitis B, C and HIV infections. Single random samples collected from 133 dialysis patients give a seroprevalence of 91.7% for HCV antibodies in contrast with the absence of seropositives between medical staff members. To assess the relative risk for HCV transmission by sexual or casual contacts we investigated also 15 samples from the relatives of patients. One spouse and the child were found positive. The differences in the epidemiology of B and C hepatitis are discussed.

Family Health↗
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[Differences in the susceptibility to HIV infection in children as a function of sex and ethnicity].

The study was conducted on 114 children (87 Romanians and 27 Turks) from an orphanage in Romania, where an AIDS outbreak was recorded due to parenteral contamination through blood transfusion or injection. The average age of the 53.5% seropositive children was of 27.63 +/- 7.88 months, versus 37.03 +/- 10.01 months in seronegative ones. The seropositivity rate was higher in Romanian children and among girls. The antibody profile in Western Blot showed that gag and pol genes specified stripes were less frequent in Turkish children.

Age Factors↗
PubMedDate not supplied

[The incidence of anti-HIV antibodies in hospitalized patients in a tuberculosis clinic].

HIV antibody prevalence was studied in 1274 patients, including 150 children, hospitalized in phthisiology services. The sixteen EIA positive samples were confirmed by the Western blot test (1.25%). The other seventeen EIA positive samples gave undetermined results in W.B. In children, antibody incidence was 7.33% versus 0.45% only in adults: this ratio seems to be characteristic for AIDS endemia in Romania, where parenteral transmission is the quasi unique way of HIV infection dissemination in children. The presence of nonspecific multiple bands in the gp 41 region was noted on seven of the seventeen undetermined samples, which is to confirm the reports about the presence of W.B. detectable anti-HIV antibodies cross-reacting with anti-mycobacterial antibodies.

Age Factors↗