2,627 research outputs found
A handbook for group discussion in the secondary school
Thesis (Ed.M.)--Boston Universit
Screening for Cytomegalovirus during Pregnancy
The epidemiology and pathogenesis of CMV infections among pregnant women have been intensely studied over the last three decades. This paper highlights recent developments that make either universal or limited serologic screening for CMV during pregnancy potentially attractive. The developments include an understanding of the pathogenesis of CMV infections, a knowledge of high-risk women, the availability of accurate methods for the serologic diagnosis of a primary CMV infection using either single or serial blood samples, accurate methods for the diagnosis of fetal infection via amniotic fluid, sensitive fetal and placental indicators for neonatal outcomes, and the availability of potentially effective interventions
Cytomegalovirus and Child Day Care
Abstract
To determine whether day-care workers acquire cytomegalovirus infection from the children they care for, we studied 610 women employed at 34 day-care centers over two years.
Forty-one percent of the caretakers were seropositive for cytomegalovirus. After adjustment for the effects of race, marital status, and age on seropositivity, the women who cared for children younger than two years of age had a significantly higher seropositivity rate (46 percent) than the women who cared for children older than two years of age (35 percent) (relative risk, 1.29; 95 percent confidence interval, 1.05 to 1.57; P\u3c0.02).
Of 202 initially seronegative caretakers (observed for an average of 305 days per woman), 19 seroconverted, for an annual seroconversion rate of 11 percent. This rate was significantly higher than the 2 percent annual rate of seroconversion among 229 seronegative women (11 of whom seroconverted) in a comparison group of female hospital employees observed for an average of 781 days per woman (relative risk, 5.0; 95 percent confidence interval, 2.4 to 10.5; P
We conclude that workers in day-care centers may acquire cytomegalovirus infection from the children in their care and that this risk is significantly greater among those who care for children less than two years of age. (N Engl J Med 1989;321:1290–6.
Passive immunization during pregnancy for congenital cytomegalovirus infection
BACKGROUND
Currently, there is no effective intervention for a primary cytomegalovirus (CMV) infection during pregnancy. METHODS
We studied pregnant women with a primary CMV infection. The therapy group comprised women whose amniotic fluid contained either CMV or CMV DNA and who were offered intravenous CMV hyperimmune globulin at a dose of 200 U per kilogram of maternal weight. A prevention group, consisting of women with a recent primary infection before 21 weeks\u27 gestation or who declined amniocentesis, was offered monthly hyperimmune globulin (100 U per kilogram intravenously). RESULTS
In the therapy group, 31 women received hyperimmune globulin, only 1 (3 percent) of whom gave birth to an infant with CMV disease (symptomatic at birth and handicapped at two or more years of age), as compared with 7 of 14 women who did not receive hyperimmune globulin (50 percent). Thus, hyperimmune globulin therapy was associated with a significantly lower risk of congenital CMV disease (adjusted odds ratio, 0.02; 95 percent confidence interval, ¡∞ to 0.15; P\u3c0.001). In the prevention group, 37 women received hyperimmune globulin, 6 (16 percent) of whom had infants with congenital CMV infection, as compared with 19 of 47 women (40 percent) who did not receive hyperimmune globulin. Thus, hyperimmune globulin therapy was associated with a significantly lower risk of congenital CMV infection (adjusted odds ratio, 0.32; 95 percent confidence interval, 0.10 to 0.94; P=0.04). Hyperimmune globulin therapy significantly (P\u3c0.001) increased CMV-specific IgG concentrations and avidity and decreased natural killer cells and HLA-DR+ cells and had no adverse effects. CONCLUSIONS
Treatment of pregnant women with CMV-specific hyperimmune globulin is safe, and the findings of this nonrandomized study suggest that it may be effective in the treatment and prevention of congenital CMV infection. A controlled trial of this agent may now be appropriate
Lack of autoantibody production associated with cytomegalovirus infection
To confirm an association between cytomegalovirus (CMV) infection and the presence of antibodies to Smith (Sm), to ribonucleoprotein (RNP), and to a component of the U1 ribonucleoproteins (U1-70 kD), we measured antibodies to these protein antigens using an enzyme immunoassay and an immunoblot. The antibodies were measured in the sera of 80 healthy subjects, one-half of whom were naturally CMV seropositive and one-half were CMV seronegative, and in eight subjects immunized with a live attenuated strain of CMV. None of the vaccinees developed antibodies to Sm, to RNP, or to U1-70 kD at either 4 or 12 months after immunization. Additionally, there was no statistically significant association between levels of antibodies to Sm or to RNP and between sera obtained from vaccinees, natural CMV seropositive individuals, and CMV seronegative individuals. One CMV seropositive serum and one CMV seronegative serum tested positive for antibodies to U1-70 kD. These data indicate that neither wild-type infection nor the live-attenuated Towne vaccine frequently induce autoantibody production
Placental enlargement in women with primary maternal cytomegalovirus infection is associated with fetal and neonatal disease
Background. Serological testing for primary maternal cytomegalovirus (CMV) infection during pregnancy is not routine, but ultrasound studies are routine. Therefore, we evaluated placental thickening in women with primary CMV infection during pregnancy. Methods. The study included 92 women with primary CMV infection during pregnancy and 73 CMV-seropositive pregnant women without primary CMV infection. Neonatal CMV transmission was determined by CMV culture of urine samples. Thirty-two women were treated with CMV hyperimmune globulin to either prevent or treat intrauterine CMV infection. Maximal placental thickness was measured by longitudinal (nonoblique) scanning with the ultrasound beam perpendicular to the chorial dish. Programmed placental ultrasound evaluations were performed from 16 to 36 weeks of gestation. Results. At each measurement between 16 and 36 weeks of gestation, women with primary CMV infection who had a fetus or newborn with CMV disease had placentas that were significantly thicker than those of women with primary CMV infection who did not have a diseased fetus or newborn (P <.0001); the latter group, in turn, P <.0001 had placentas that were significantly thicker than those of seropositive control subjects (P <.0001). For both women P <.0001 with and women without diseased fetuses or newborns, receipt of hyperimmune globulin after primary CMV infection was associated with statistically significant reductions in placental thickness (P <.001). Placental vertical P <.001 thickness values, which are predictive of primary maternal infection, were observed at each measurement from 16 to 36 weeks of gestation, and cutoff values ranged from 22 mm to 35 mm, with the best sensitivity and specificity at 28 and 32 weeks of gestation. Conclusions. Primary maternal CMV infection and fetal or neonatal disease are associated with sonographically thickened placentas, which respond to administration of hyperimmune globulin. These observations suggest that many of the manifestations of fetal and neonatal disease are caused by placental insufficiency
One-Loop QCD Mass Effects in the Production of Polarized Bottom and Top Quarks
The analytic expressions for the production cross sections of polarized
bottom and top quarks in annihilation are explicitly derived at the
one-loop order of strong interactions. Chirality-violating mass effects will
reduce the longitudinal spin polarization for the light quark pairs by an
amount of , when one properly considers the massless limit for the final
quarks. Numerical estimates of longitudinal spin polarization effects in the
processes and are presented.Comment: 17 p. (5 figs available upon request), LaTeX, MZ-TH/93-30, RAL/93-81,
FTUV/93-4
Cytomegalovirus Infections among African-Americans
<p>Abstract</p> <p>Background</p> <p>Since African-Americans have twice the prevalence of cytomegalovirus (CMV) infections as age-matched Caucasians we sought to determine the ages and possible sources of infection of African-American children.</p> <p>Methods</p> <p>Subjects were 157 African-American healthy children and adolescents and their 113 household adults in Richmond VA. Families completed a questionnaire, provided saliva for antibody testing, and adolescents were interviewed regarding sexual activity.</p> <p>Results</p> <p>Regardless of age CMV seropositivity was not associated with gender, breast feeding, health insurance, sexual activity, or household income, education, or size. In the final regression model, prior CMV infection in adults was over two-fold higher than in children (chi-square = 18.8, p < 0.0001). At one year of age the CMV seropositivity rate was 11% (95%CI = 4% – 24%) and increased 1.8% each year until age 13 years. Between ages 13 and 20 years the CMV seropositivity rate remained between 22% and 33%. For adults, the CMV seropositivity rate was 84% in 21 year olds (95%CI = 69%–.92%). There was no association between CMV infections of the children and their mothers but CMV infections among siblings were associated.</p> <p>Conclusion</p> <p>We observed that African-American children had CMV seroprevalence rates by age 20 years at less than one-half of that of their adult mothers and caregivers. Sibling-to-sibling transmission was a likely source of CMV infections for the children. The next generation of African-American women may be highly susceptible to a primary CMV infection during pregnancy and may benefit from a CMV vaccine.</p
Bacterial Artificial Chromosome Clones of Viruses Comprising the Towne Cytomegalovirus Vaccine
Bacterial artificial chromosome (BAC) clones have proven invaluable for genetic manipulation of herpesvirus genomes. BAC cloning can also be useful for capturing representative genomes that comprise a viral stock or mixture. The Towne live attenuated cytomegalovirus vaccine was developed in the 1970s by serial passage in cultured fibroblasts. Although its safety, immunogenicity, and efficacy have been evaluated in nearly a thousand human subjects, the vaccine itself has been little studied. Instead, genetic composition and in vitro growth properties have been inferred from studies of laboratory stocks that may not always accurately represent the viruses that comprise the vaccine. Here we describe the use of BAC cloning to define the genotypic and phenotypic properties of viruses from the Towne vaccine. Given the extensive safety history of the Towne vaccine, these BACs provide a logical starting point for the development of next-generation rationally engineered cytomegalovirus vaccines
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