Screening for viral and protozoal infections in pregnancy. A review

Transcriptome Analysis Reveals Biosynthesis of Important Bioactive Constituents and Mechanism of Stem Formation of Dendrobium huoshanense

The stem of Dendrobium huoshanense C.Z. Tang and S.J. Cheng was widely used as a medicinal herb in health care products due to its broad pharmacological activities. However, the molecular regulation mechanism of stem development and biosynthetic pathways of important bioactive substances are still unclear in D. huoshanense. In this study, the bioactive compounds in leaves, stems and roots, and the identification of candidate genes involved in stem formation and biosynthesis of active compounds via transcriptome sequence were analyzed. The accumulation of total polysaccharides and flavonoids were varied significantly in different tissues. A comparative transcriptomic analysis revealed several differentially expressed genes (DEGs) involved in polysaccharides biosynthesis (103 genes), including fructose and mannose related genes (29 genes) and glycosyltransferase genes (74 genes), and flavonoids biosynthesis (15 genes). Some candidate genes that participated in photoperiod regulation (27 genes), starch and sucrose metabolism (46 genes), and hormone-induced activation of signaling pathways (38 genes) may be involved in stem formation. In sum, this study provides a foundation for investigating the molecular processes in the biosynthesis of active compounds and stem development. The transcriptome data presented here provides an important resource for the future studies of the molecular genetics and functional genomics in D. huoshanense and optimized control of the active compounds produced by D. huoshanense.

Congenital cytomegalovirus infection: a long-standing problem still seeking a solution

OBJECTIVE

The purpose of this study was to review the accuracy of current tests used for the diagnosis of in utero cytomegalovirus infection and to discuss the potential value of preconceptional and postconceptional screening programs for prevention of congenital infection.

STUDY DESIGN

A computer-assisted search was performed for relevant English language publications between 1987 and 1994. We identified 119 cases of suspected intrauterine cytomegalovirus infection in which either amniotic fluid or fetal blood had been analyzed antenatally.

RESULTS

Congenital cytomegalovirus infection affects 0.5% to 2.5% of all newborns. The rate of transmission to the fetus after primary infection during pregnancy ranges from 15% to 50%. Of the fetuses infected in utero, 10% exhibit congenital cytomegalovirus syndrome. Evaluation of 119 cases of suspected infection has shown that polymerase chain reaction and cultures of amniotic fluid are the most reliable tests for prenatally determining the presence of viral particles. However, efficacy of routine antenatal screening in reducing the rate of fetal disease is limited.

CONCLUSION

It is concluded that at present the accuracy of tests used for the diagnosis of in utero cytomegalovirus infection is undetermined. Serologic screening of all pregnant women is of limited value and at present is not recommended.

Congenital cytomegalovirus infection

OBJECTIVE

Congenital cytomegalovirus is the most common viral infection affecting approximately 1% of newborns. The virus can be transmitted to the fetus during both primary and recurrent infection. Although most of the infants are asymptomatic at birth, up to 15% develop late complications. The annual cost of treating cytomegalovirus infection complications in the USA is two billion US dollars. Many issues regarding cytomegalovirus infection such as routine screening, antenatal diagnosis and vaccination during pregnancy are unsettled and disputed. The aim of this article is to review the current literature on the subject and to draw some conclusions.

DESIGN

Review of the current literature.

CONCLUSIONS

At present, it appears that there is no indication for routine prenatal screening, while other issues, such as the most accurate method for antenatal diagnosis and the indications for pregnancy termination are, as yet, unsettled.

Toxoplasmosis in pregnancy

Primary infection with Toxoplasma gondii in pregnant women occurs all over the world with frequencies between 0.1-1%. In approximately 40% of the cases, the unborn child is infected. The risk of fetal infection increases during pregnancy, while at the same time the risk of severe disease decreases. As a result, infants with congenital toxoplasmosis are mostly asymptomatic at birth, but long-term studies indicate that up to 85% of them will develop sequelae including chorioretinitis (leading to severe impairment of vision), hearing loss or mental retardation. Early recognition of maternal infection and treatment with spiramycin or pyrimethamine-sulphadiazine will reduce the parasitic colonization of the placenta by more than 60% and prevent infection in the fetus. If fetal infection has already occurred, maternal treatment modifies the fetal disease. Therapy during the first year of life improves the prognosis. It is possible today to identify infected fetuses by prenatal diagnosis based on detection of the parasite in cord blood, amniotic fluid and placental tissue. Specific antibodies and non-specific signs of infection in fetal blood give additional information. Advances in laboratory techniques have made it feasible to consider serological surveillance of pregnant women. The present recommendation is that each country should provide data on the incidence of toxoplasma infection in pregnancy and thereby decide whether it represents a problem and what measures should be adopted. This paper summarizes the present knowledge of the parasite and its implication for the mother and unborn child. The effect and problems of primary and secondary prevention in pregnancy are discussed as well as the efficacy of treatment. The need for future research including long-term follow-up studies are emphasized.