Transmission of cytomegalovirus.
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Breast Feeding↗
Biomedical subjects
M Barbi
Publications and source records attributed to M Barbi.
Stabilization of ratchet dynamics by weak periodic signals.
We study the influence of weak periodic signals on the transport properties of underdamped ratchets. We find that the constant current intervals related to the ratchet can be significantly enlarged by a weak subharmonic signal that is in phase with the internal driver. This stabilization phenomenon is found to exist both in absence and in presence of noise. The dependence of this effect on the phase of the applied signal is also investigated.
Journal Article↗
CMV gB genotypes and outcome of vertical transmission: study on dried blood spots of congenitally infected babies.
BACKGROUND: The role of the virulence of the infecting cytomegalovirus (CMV) strain in the transmission of the virus from mother to fetus and the outcome of the fetal infection has not received much attention yet. Molecular analysis of the gene coding for the surface glycoprotein B (gB) has been used to investigate the relationship between genotype and virulence in groups of immunosuppressed patients. OBJECTIVES: (1) to assess the prevalence of different gB genotypes in babies with congenital CMV infection; (2) to investigate the possible relationship between genotype and severity of congenital CMV disease; (3) to evaluate the possibility of using dried blood on Guthrie cards (DBS) for genotyping. STUDY DESIGN: CMV DNA was extracted from DBS and from urine/saliva samples collected in the first two weeks of life of 98 congenitally infected babies, half of which were symptomatic at birth. Genotyping was performed through RFLP analysis of the region corresponding to the cleavage site of the gB protein. RESULTS: The most prevalent genotype was gB1 (42%) followed by gB3 (26%), gB2 (19%) and gB4 (13%). Rates of disease and CNS damages were higher among children infected by gB1 (35%, 17%) and gB3 (31%, 28%) than in those infected by gB2 and gB4 (20%, 17% and 13%, 15%, respectively). These differences however did not reach the statistical significance. The parallel typing of DBS and urine/saliva strains gave a full concordance of results. CONCLUSIONS: All four major CMV gB genotypes (gB1-4) can cause a congenital infection but none seems to be associated to the development and the severity of disease. The possibility of using the neonatal DBS for genotyping opens a way to the examination of large numbers of cases of congenital CMV infection.
Blood Specimen Collection↗
Cytomegalovirus DNA detection in Guthrie cards: a powerful tool for diagnosing congenital infection.
BACKGROUND: A simple and reliable diagnosis of congenital cytomegalovirus infection is necessary both for clinical and epidemiological purposes. This could be accomplished through the demonstration of cytomegalovirus (CMV) DNA in blood spots (DBS) on Guthrie cards. OBJECTIVES: (1) To assess the sensitivity and specificity of the method (DBS test) in diagnosing congenital CMV infection compared with viral isolation and (2) to evaluate the applications of the test to the late diagnosis of congenital CMV. STUDY DESIGN: The method was tested on the cards of (1) 509 babies examined through viral isolation within their third week of life (72 positive cases) and (2) 191 children studied after 3 weeks of life (25 days to 5 years). Blood was eluted from Guthrie cards and heat extracted. The products of a nested polymerase chain reaction (PCR) amplifying one region in the CMV glycoprotein B (gB) gene were detected by agarose gel electrophoresis. RESULTS: DBS test was positive in all 72 congenitally infected babies and in four of the 437 negative at cytomegalovirus isolation (sensitivity 100%, specificity 99%). Infection in 16 of the 92 infants with a late viral isolation was demonstrated to be congenital by the test, which also detected congenital infection in 18 of 83 children in whom viral culture was not performed (13 with and five without symptoms). Fifty-six additional control cases tested negative. CONCLUSIONS: DBS test is a reliable assay for diagnosing congenital cytomegalovirus infection and could be used as an alternative to viral culture. It is able to reveal whether ascertained CMV infection is congenital or postnatal at an age when viral isolation is not able to do so. It can assess the role of risky procedures such as transfusion and it can ascertain the etiology of morbid conditions diagnosed late or of controversial origin.
Blood Specimen Collection↗
Phase locking effect and current reversals in deterministic underdamped ratchets
We study the transport properties (currents) of deterministic underdamped ratchets in terms of phase locking dynamics. The occurrence of reverse currents is interpreted in terms of different stability properties of the periodic rotating orbits and is shown to exist also in the absence of bifurcations from chaos to periodic motion. We briefly discuss the effects of noise on this phase locked dynamics.
Journal Article↗
Heart rate and blood pressure response to short-term head-down bed rest: a nonlinear approach.
Although it is well-known that prolonged exposure to microgravity environment such as in space travel results in derangements of orthostasis, recent evidence suggests that even short-term exposure may have similar effects and parallels such common examples as prolonged bed rest. Whereas spectral analysis of heart rate and systolic blood pressure have been unable to detect changes, we hypothesized that nonlinear indexes may be better able to uncover such perturbations. Eighteen healthy subjects were exposed to 4-hour head-down tilt, and of these, 4 exhibited fainting. Two nonlinear indexes, mutual information and recurrence quantification were used to analyze the data. Only recurrence quantification was able to detect a "decoupling" of heart rate and systolic blood pressure at rest using discriminant analysis (p < 0.05). These results suggest that orthostatic intolerance may be due to a decoupling of heart rate from systolic blood pressure reflexive activity occurring at rest.
Adult↗
Nonlinear activity of identified Lymnaea neurons.
Two long-lasting discharges of action potentials were recorded from a buccal cell of the pond snail, respectively, before and after superfusing the preparation with low-calcium solution. The corresponding sequences of interspike intervals were then analysed by the nonlinear prediction methods. The results yield evidence of a small but clear nonlinearity only in the second of analysed tachograms. This finding is evaluated and discussed.
Action Potentials↗
Immunity to poliomyelitis, diphtheria and tetanus in pediatric patients before and after renal or liver transplantation.
Few studies have considered the safety, efficacy and appropriateness of vaccinations in pediatric patients before and after solid organ transplantation. The aim of this study was to evaluate the immune status after primary vaccination to diphtheria, tetanus and poliomyelitis in pediatric patients before and after hepatic transplantation and to poliomyelitis in pediatric patients before and after renal transplantation. All the patients had received a complete primary immunization schedule for diphtheria and tetanus and poliomyelitis. Immunity to the three polioviruses was evaluated in 56 patients with renal transplant, 27 on chronic dialysis and 33 controls and in 39 patients with hepatic transplant, 25 with chronic hepatic failure and their 36 controls. Immunity to diphtheria and tetanus was evaluated in 52 liver transplant patients, 29 children with chronic hepatic failure and 54 healthy children. Renal transplant patients were less protected and had lower antibody geometric mean titers than healthy controls for polioviruses 1 and 2. Whereas, protection in the children liver transplant patients was similar to that in their controls. Patients with chronic hepatic failure had higher antibody geometric mean titers to diphtheria and polioviruses 1 and 3 than their control group. Immunosuppression after transplantation has a negative influence on the immune status after primary vaccination in children with renal transplant. Whereas children with chronic hepatic failure have higher antibodies than a normal population. When possible, it could be advisable to individualize immunization schedules in patients at high risk.
Adolescent↗
Immunization with both T cell-dependent and T cell-independent vaccines augments HIV viral load secondarily to stimulation of tumor necrosis factor alpha.
Vaccination of HIV-infected individuals increases HIV viral load, reduces CD4 cell counts, and might influence disease progression. Because these deleterious effects are postulated to be secondary to a direct activation of T lymphocytes induced by the immunogen, we compared immunologic and virologic effects of a T cell-dependent and a T cell-independent vaccine. Seventeen HIV-infected children were immunized with influenza (FLU) (T cell-dependent) or pneumococcal (PNEUMO) (T cell-independent) vaccines. HIV viral load and type 1 (IL-2 and IFN-gamma) and type 2 (IL-4 and IL-10) cytokine production were evaluated before and 7, 14, and 28 days after vaccination. Slopes of CD4 cell counts analyzed 6 months before and 6 months after vaccination were not significantly different. HIV viral load increased in both groups of children despite the fact that type 1 cytokine production and the type 1-to-type 2 ratio increased in FLU-vaccinated but not in PNEUMO-vaccinated patients. Thus, an increase in HIV viral load in the absence of T cell activation (as measured by cytokine production) was observed in PNEUMO-vaccinated children. Because polysaccharides of the bacterial cell wall stimulate TNF-alpha production by monocyte-macrophages and TNF-alpha was shown to stimulate HIV replication directly on activation of NF-kappa b after binding the long terminal repeat (LTR) sequences of HIV, we measured TNF-alpha production and observed a significant increase in both groups of vaccines. These data suggest that an increase in HIV viral load can be observed in vaccinated HIV-infected children even independent of direct antigen-induced activation of T lymphocytes, and that augmented production of TNF-alpha might play a role in this phenomenon.
Bacterial Vaccines↗
Congenital cytomegalovirus infection in a northern Italian region. NEOCMV Group.
Knowledge of the prevalence of congenital cytomegalovirus infection is necessary to evaluate the need for prevention. We performed a multicentre one-year study involving 11 neonatology divisions to ascertain the prevalence in Lombardy. Cytomegalovirus was isolated by culturing saliva samples from all babies born (n = 1268) of two 15-day sample periods and from 185 neonates with suspected congenital CMV based on clinical and laboratory findings and the history. The overall prevalence of congenital infection was 0.47% (6/1268) in the sample period group and 5% (9/185) in the second group. Clinical monitoring revealed sequelae in two of three children with symptomatic infection and no asymptomatic child at age two years. In a subgroup of 205 babies including 14 of the infected infants we also evaluated a test to detect cytomegalovirus DNA in the Guthrie cards obtained in neonatal screening for genetic and metabolic disorders. The test's sensitivity was 100% and specificity 98.5%, encouraging its use for early identification of infected neonates and for large epidemiological studies.
Child, Preschool↗
Use of Guthrie cards for the early diagnosis of neonatal herpes simplex virus disease.
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DNA, Viral↗
In vitro activity of acetylsalicylic acid on replication of varicella-zoster virus.
Topical application of a mixture of acetylsalicylic acid (ASA) and diethyl ether is effective in the treatment of acute herpes zoster and postherpetic neuralgia. To study whether the other-than-analgesic effects of that treatment could be due to an antiviral activity of ASA the effects of the drug on the replication of varicella zoster virus (VZV) were assessed by the fluorescent focus assay on MRC5 and Vero cells. ASA caused a marked reduction in the spread of infection in MRC5 monolayers while in growing Vero cells the effective dose proved toxic. ASA concentrations (5-10 mM) which were effective in vitro against VZV are higher than the plasma concentrations attained in the standard treatment of chronic inflammatory states, but are consistent with the skin concentration attained by topical application of ASA/diethyl ether mixture. These data support similar findings relating the antiviral activity of acetylsalicylic acid to influenza virus, CMV, and HIV.
Animals↗
Dynamics of the neural discharge in snail neurons.
Spike trains recorded under weak sinusoidal driving from central neurons of Lymnaea stagnalis appear quite irregular and envisage the possibility of an underlying chaotic process. Therefore, the sequences of interspike intervals are analyzed in the framework of non-linear dynamics. Since, for several reasons, these sequences are rather short, the analysis is performed by using methods of non-linear forecasting. To reject the null hypothesis that the original time series is a realization of a linear stochastic process with the same autocorrelation function, the results obtained on the original data are compared with those from surrogate data sets. Some 'non-linear' predictability occurs only in narrow regions of the space of stimulus parameters and the frequency of perturbation is critical in determining it. Moreover, it is shown that such behavior can be qualitatively mimicked by the FitzHugh-Nagumo model driven by a weak sinusoidal signal plus noise. It is argued that the narrowness of the non-linear predictability regions renders quite unlikely the detection of deterministic dynamics in the activity of these neurons.
Action Potentials↗
Detection of nonlinearity in the healthy heart rhythm.
Sequences of interbeat intervals from two groups of subjects, 24 in relaxed and 10 in sleeping condition were analyzed by the nonlinear predictor method as well as by a method, proposed recently, able to directly estimate the time series nonlinearity. The nonlinear predictability of the R-R intervals is tested by using surrogate data. The results obtained with both methods show that nearly all the sequences exhibit a statistically meaningful degree of nonlinearity. This raises the question whether such nonlinearity encodes information about the physiological condition of the examined subjects.
Electrocardiography, Ambulatory↗
Cytomegalovirus in peripheral blood leukocytes of infants with congenital or postnatal infection.
BACKGROUND: Cytomegalovirus (CMV) is the most frequent agent of viral infection in the fetus; it causes varying damage, particularly neurologic, which becomes evident at birth or in infancy in about 20% of infected individuals. Postnatal acquisition is usually asymptomatic and without sequelae. Laboratory diagnosis of congenital and postnatal infection is based on the demonstration of virus in urine. OBJECTIVES: To investigate the systemic spread of CMV in neonates with congenital or postnatal infection and to evaluate its significance in diagnosis and in monitoring anti-CMV treatments. DESIGN: Quantitative determinations of infective CMV (viremia) and viral antigen pp65 (antigenemia) were performed on peripheral blood leukocytes (PBL) from the buffy coat of heparinized blood from children with a diagnosis of congenital (n = 19) or postnatal (n = 19) infection based on viral isolation from urine. RESULTS: Antigen pp65 in PBL was detected particularly in children with symptomatic infection, both congenital (100%) and postnatal (79%; P > 0.05), and significantly less frequently (50%; P < 0.001) in those with asymptomatic infection. Viremia was observed less often but always in association with antigenemia. Both tests became negative within 6 months. Neither viral titer nor persistent positivity was related to clinical manifestations. In the nine infants given anti-CMV therapy (ganciclovir and/or hyperimmune gamma-globulins) an early suspension of treatment resulted in the appearance of antigenemia and/or viremia. CONCLUSIONS: Cytomegalovirus was detected in PBL mainly in the most severely affected children. Monitoring antigenemia and viremia in CMV-infected infants is recommended to demonstrate persistent systemic infection and to evaluate virologic results of treatment.
Antigens, Viral↗
Double resistance to ganciclovir and foscarnet of four human cytomegalovirus strains recovered from AIDS patients.
Four human cytomegalovirus (HCMV) isolates from four different AIDS patients treated with both ganciclovir and foscarnet and not responding clinically to antiviral treatment, were studied in order to verify the occurrence of double resistance to both drugs, and to define whether single or multiple HCMV strains could be responsible for the double resistance. Peripheral blood leukocytes (PBL), the relevant conventional viral isolates, and plaque-purified strains from all four patients were examined by antiviral drug susceptibility testing by an immediate-early antigen plaque reduction assay and by restriction fragment length polymorphism (RFLP) analysis using polymerase chain reaction (PCR)-amplified multiple genome regions and endonucleases. All four HCMV strains had a high level of resistance to both ganciclovir and foscarnet. A single HCMV strain was shown to be responsible for the dual resistance in each patient. HCMV strain identity and uniqueness were shown for each of the four patients in blood samples, viral isolates, and plaque-purified strains. In addition, in two patients the same single HCMV strain shifted progressively from drug sensitivity to ganciclovir and then to ganciclovir-foscarnet resistance. These findings document that resistance to both ganciclovir and foscarnet of HCMV strains recovered from blood of AIDS patients represents an emerging problem. Although it is known that multiple HCMV strains may cocirculate in the blood of AIDS patients, single strains appear to be responsible for the dual resistance. Molecular mechanisms responsible for the double resistance of the four reported strains are under study.
AIDS-Related Opportunistic Infections↗
Dynamical model for DNA sequences.
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Journal Article↗
Four dually resistant human cytomegalovirus strains from AIDS patients: single mutations in UL97 and UL54 open reading frames are responsible for ganciclovir- and foscarnet-specific resistance, respectively.
Four human cytomegalovirus strains with double resistance to both ganciclovir and foscarnet were recovered from acquired immunodeficiency syndrome (AIDS) patients. The four isolates were genetically unrelated and each of them consisted of a single viral population. In addition, for each isolate, UL97 and UL54 open reading frames sequencing showed a single aminoacid change in a conserved domain of each of the two genes.
AIDS-Related Opportunistic Infections↗