Review: psychosocial well-being of parents and their children born after assisted reproduction.

OBJECTIVE: To critically review the empirical literature published from 1980 through June 2000 on the psychosocial well-being of parents and their children born after assisted reproduction. METHODS: A computer-based literature search of PsycINFO and Medline was conducted. Empirical studies were reviewed to document the psychosocial impact of infertility and its treatment on the families involved in terms of quality of parenting, family functioning, and child development. RESULTS: Several common findings appeared across the studies reviewed. With regard to quality of parenting and family functioning, mothers of children born using assisted reproduction report less parenting stress and more positive mother- and father-child relationships than mothers of naturally conceived children. In most cases, no statistically significant differences in child functioning in terms of emotions, behavior, self-esteem, or perceptions of family relationship have been reported. CONCLUSIONS: The summary findings are positive and reassuring for parents and their children born after assisted reproduction. This critique of the published literature provides interpretative and methodological refinements for future research.

In vitro fertilization and the family: quality of parenting, family functioning, and child psychosocial adjustment.

This study examined associations between homologous in vitro fertilization (IVF) and quality of parenting, family functioning, and emotional and behavioral adjustment of 3-7-year-old children. A cross-sectional survey was conducted in Taiwan with 54 IVF mother-child pairs and 59 mother-child pairs with children conceived naturally. IVF mothers reported a greater level of protectiveness toward their children than control mothers. Teachers, blind to condition, rated IVF mothers as displaying greater warmth but not overprotective or intrusive parenting behaviors toward their children. Teachers scored children of IVF as having fewer behavioral problems than control children. In contrast, IVF mothers reported less satisfaction with aspects of family functioning. Family composition moderated parenting stress: IVF mothers with only 1 child perceived less parenting stress than did those in the control group.

Bispecific monoclonal antibodies mediate binding of dengue virus to erythrocytes in a monkey model of passive viremia.

Dengue viruses (DEN), causative agents of dengue fever (DF) and more severe dengue hemorrhagic fever (DHF)/dengue shock syndrome, infect over 100 million people every year. Among those infected, up to one-half million people develop DHF, which requires an extensive hospital stay. Recent reports indicate that there is a significant correlation between virus titer in the bloodstream of infected individuals and the severity of the disease, especially the development of DHF. This suggests that if there is a procedure to reduce viremia in infected subjects, then the severity of the disease may be controlled during the critical early stages of the disease before it progresses to DHF. We have generated bispecific mAb complexes (heteropolymer(s), HP), which contain a mAb specific for the DEN envelope glycoprotein cross-linked with a second mAb specific for the primate E complement receptor 1. These HP facilitate rapid binding of DEN to human and monkey E in vitro, with approximately 90% bound within 5 min. Furthermore, in a passive viremia monkey model established by continuous steady state infusion of DEN, injection of HP during the steady state promoted rapid binding of DEN to the E, followed by subsequent clearance from the vascular system. Moreover, HP previously infused into the circulation is capable of efficiently capturing a subsequent challenge dose of DEN and binding it to E. These data suggest that HP potentially can be useful for alleviating DEN infection-associated symptoms by reducing titers of free virus in the vascular system.

Heteropolymer-mediated clearance of immune complexes via erythrocyte CR1: mechanisms and applications.

Opsonization of particulate pathogens by antibodies and complement can lead to their binding to the complement receptor (CR1), specific for C3b, on primate erythrocytes (E). This process of immune adherence may play a role in immunologic defense by immobilizing bacteria and viruses, thus preventing them from leaving the bloodstream to invade susceptible tissue and organs. Immune adherence of C3b-opsonized and immune complexed pathogens to E may also facilitate their transfer to, and destruction by, fixed tissue macrophages. We have used mAbs specific for CR1 crosslinked with pathogen specific mAbs to generate heteropolymers (HP) which can bind a wide range of substrates to primate erythrocytes. Both prototype and bonafide pathogens bound to primate E via HP are handled in the circulation of non-human primates in a manner which appears to be virtually identical to the mechanism by which C3b-opsonized substrates bound to E CR1 are cleared. In this process of focused phagocytosis, Fc receptors on the phagocytic cell engage the E-bound complex, CR1 is removed by proteolysis, and the entire immune complex and CR1 are internalized while sparing the E. It may be possible to use HP to target pathogens in the bloodstream in a wide range of therapeutic applications.

The HCV core protein acts as a positive regulator of fas-mediated apoptosis in a human lymphoblastoid T cell line.

Hepatitis C virus (HCV) is a major human pathogen causing mild to severe liver disease worldwide and is remarkably efficient at establishing persistent infections. Previously, we have shown that the core protein has an immunomodulatory function including the suppression of T lymphocyte responses to viral infection. To investigate the underlying mechanism for the role of core protein in immune modulation, we examined the effect of core on the sensitivity of the human T cell line, Jurkat, to Fas-mediated apoptosis. The transient and stable expression of core protein in Jurkat cells increased the sensitivity of cells to Fas-mediated apoptosis when compared to control cells expressing vector DNA alone. In addition, we demonstrated that the core protein binds to the cytoplasmic domain of Fas which may enhance the downstream signaling event of Fas-mediated apoptosis. The expression of core protein did not alter the cell surface expression of Fas, indicating that the increased sensitivity of core-expressing cells to Fas ligand was not due to upregulation of Fas. Furthermore, we observed the augmentation of caspase-3 activity in core-expressing cells. These results suggest that the core protein may promote the apoptosis of immune cells during HCV infection via the Fas signaling pathway, thus facilitating HCV persistence.

Activation-dependent degradation of protein kinase C eta.

Prolonged activation of protein kinase Cs (PKCs) by long-term treatment of cells with phorbol ester tumor promoters down-regulates the expression of many PKCs. To investigate the molecular mechanisms involved in the down-regulation of PKC eta, we expressed the novel PKCs eta and θ and various mutant forms in baby hamster kidney cells. Upon overexpression, constitutively active PKC eta, but not wild type or kinase-dead PKC eta, underwent rapid degradation to generate several lower molecular weight polypeptides. When co-expressed with active kinases, kinase-dead PKC eta with a pseudosubstrate site mutation designed to give an active conformation was down-regulated while the wild type PKC eta was not. These results suggest requirements for kinase activity and an active conformation for down-regulation of PKC eta. Treatment with the proteasome inhibitors N-Ac-Leu-Leu-norleucinal and lactacystin led to accumulation of PKC eta proteolytic products and potentially ubiquitinated forms. While wild type PKC eta localizes mostly to the detergent-soluble fraction of the cell, a significant portion of full-length constitutively active PKC eta and of kinase-dead, active conformation PKC eta were found in the detergent-insoluble fraction. Several proteolytic fragments of constitutively active PKC eta also were found in the detergent insoluble fraction. These full-length and proteolytic fragments of PKC eta in the detergent-insoluble fraction accumulated further in the presence of proteasome inhibitors. These data suggest that active conformation PKC eta accumulates in the detergent-insoluble compartment, is degraded by proteolysis in the presence of kinase activity, and that the cleavage products undergo further degradation via ubiquitin-mediated degradation in the proteasome. Oncogene (2000) 19, 4263 - 4272

Caspase 3-dependent killing of host cells by the parasite Entamoeba histolytica.

The parasite Entamoeba histolytica is named for its ability to lyse host tissues. To determine the factors responsible, we have initiated an examination of the contribution of parasite virulence factors and host caspases to cellular destruction by the parasite. Amoebic colitis in C3H/HeJ mice was associated with extensive host apoptosis at sites of E. histolytica invasion. In vitro studies of E. histolytica-Jurkat T-cell interactions demonstrated that apoptosis required contact via the amoebic Gal/GalNAc lectin, but was unaffected by 75% inhibition of the amoebic cysteine proteinases. Parasite-induced DNA fragmentation was unaffected in caspase 8-deficient Jurkat cells treated with the caspase 9 inhibitor Ac-LEHD-fmk. In contrast, caspase 3-like activity was observed within minutes of E. histolytica contact and the caspase 3 inhibitor Ac-DEVD-CHO blocked Jurkat T cell death, as measured by both DNA fragmentation and 51Cr release. These data demonstrate rapid parasite-induced activation of caspase 3-like caspases, independent of the upstream caspases 8 and 9, which is required for host cell death.

A balance of signaling by Rho family small GTPases RhoA, Rac1 and Cdc42 coordinates cytoskeletal morphology but not cell survival.

Rho family GTPases are known to be involved in cytoskeletal reorganization. We examined the possibility that these functions may be dictated by a balance of Rho family GTPase signaling. Using transient viral expression of RhoA, Rac1, Cdc42 and their mutants, as well as C3 exoenzyme, we altered cytoskeletal organization under normal growth conditions. Overexpression of wild-type or constitutively active forms of the Rho family GTPases led to their respective activation phenotypes. Overexpression of dominant negative forms of given Rho family GTPases led to a phenotype consistent with activation of the other Rho family GTPase. Treatment with C. difficile toxin A, that inactivates all Rho family GTPases, led to the transient appearance of a variety of activation phenotypes. Previously, we reported that inactivation of Rho led to induction of apoptosis, implying that Rho may play an important role in cell survival signaling. This signaling, however, is not affected by expression of any forms of Rac1 or Cdc42, and only inactivation of Rho led to induction of apoptosis. Rho family GTPases appear to coordinate cytoskeletal organization by a balance of signaling, while cell survival is regulated by a distinct Rho-mediated signaling pathway.

Class I MHC molecule-mediated inhibition of Sindbis virus replication.

The threshold for systemic viral infection relies on the amplification of virus at a primary infection site. We have identified that class I MHC molecules can trigger the inhibition of replication of Sindbis virus in a haplotype- and allele-specific manner. Class I MHC molecules of H-2d haplotypes exhibit a strong inhibitory effect whereas H-2k haplotypes show minimal inhibition of Sindbis viral replication. By a single gene transfection of H-2d class I MHC molecules, into cells that express class I MHC molecules of H-2k haplotype and are susceptible to viral replication, these cells became resistant to viral replication. The inhibition of viral replication by class I MHC molecules occurs neither during the stage of virus entry/endocytosis nor during virus maturation. Rather, viral-specific RNA replication, as well as viral gene expression, are inhibited in cells expressing inhibitory class I MHC molecules. This class I MHC molecule-mediated inhibition requires newly synthesized host gene products, implying the activation of an intracellular signaling mechanism that is triggered by specific class I MHC molecules.

Differential downstream functions of protein kinase Ceta and -theta in EL4 mouse thymoma cells.

Sensitive EL4 mouse thymoma cells (s-EL4) respond to phorbol esters with growth inhibition, adherence to substrate, and production of cytokines including interleukin 2. Since these cells express several of the phorbol ester-sensitive protein kinase C (PKC) isozymes, the function of each isozyme remains unclear. Previous studies demonstrated that s-EL4 cells expressed substantially more PKCeta and PKCtheta than did EL4 cells resistant to phorbol esters (r-EL4). To examine potential roles for PKCeta and PKCtheta in EL4 cells, wild type and constitutively active versions of the isozymes were transiently expressed using a Sindbis virus system. Expression of constitutively active PKCeta, but not PKCtheta, in s- and r-EL4 cells altered cell morphology and cytoskeletal structure in a manner similar to that of phorbol ester treatment, suggesting a role for PKCeta in cytoskeletal organization. Prolonged treatment of s-EL4 cells with phorbol esters results in inhibition of cell cycling along with a decreased expression of most of the PKC isozymes, including PKCtheta. Introduction of virally expressed PKCtheta, but not PKCeta, overcame the inhibitory effects of the prolonged phorbol ester treatment on cell cycle progression, suggesting a possible involvement of PKCtheta in cell cycle regulation. These results support differential functions for PKCeta and PKCtheta in T cell activation.

Endogenous presentation of a nascent antigenic epitope to CD8+ CTL is more efficient than exogenous presentation.

Cytotoxic T lymphocytes (CTL) recognize short antigenic peptides in association with class I MHC molecules at the cell surface. Newly synthesized viral polypeptides are processed in the cytoplasm and the fragments of antigen are transported into the endoplasmic reticulum (ER) via a peptide transporter where they complex with nascent class I molecules. The peptide-MHC complex is transported to the cell surface and presented to CTL. Sequence analysis of endogenously expressed, MHC-associated self or viral antigens indicates that the naturally processed peptides bound to class I MHC molecules are in general 9 +/- 1 residues long. Peptides bound to specific class I MHC molecules have in common allele-specific motifs of conserved residues. The motif for the class I Kd molecules has been shown to be nine or 10 residues with the sequence X-Tyr-(X)6-I/L or X-Tyr-(X)7-I/L. The Tyr residue at the second position and the I/L residue at the ninth position are allele-specific anchor residues which appear to be required for binding of the peptide to Kd. To examine the stringency of the requirement for Tyr at the second position, we have performed saturation mutagenesis of a minigene encoding the class I Kd-restricted influenza HA210-219 site at the Tyr residue 211. A series of 10 mutants was tested for effects on target-cell sensitization. Most amino acid substitutions for the Tyr residue resulted in a loss of endogenous peptide recognition by HA210-219 reactive CTL, consistent with the critical role of the Tyr at the second position for interaction with Kd molecules. One mutant gene-product encoding a His substitution for the Tyr residue was recognized by CTL. However, the corresponding synthetic peptide containing a His substitution at the dominant anchor position bound only weakly to Kd, and target cells treated with the peptide were poorly recognized by CTL. The endogenous His-containing peptide was also less stably associated with class I MHC Kd molecules at the cell surface than the wild-type Tyr peptide. These data indicate that endogenous antigenic peptides may bind newly-synthesized class I MHC molecules in the ER more efficiently than fully formed class I molecules at the cell surface and that endogenous peptides may dissociate from class I MHC molecules at different rates. The implication of these findings for CTL recognition and epitope mapping are discussed.

Inactivation of the small GTP binding protein Rho induces multinucleate cell formation and apoptosis in murine T lymphoma EL4.

The small G-protein Rho regulates the actin microfilament-dependent cytoskeleton. Exoenzyme C3 of Clostridium botulinum ADP-ribosylates Rho at Asn41, a modification that functionally inactivates Rho. Using a Sindbis virus-based transient gene expression system, we studied the role of Rho in murine EL4 T lymphoma cells. We generated a double subgenomic infectious Sindbis virus (dsSIN:C3) recombinant which expressed C3 in >95% of EL4 cells. This intracellular C3 resulted in modification and inactivation of virtually all endogenous Rho. dsSIN:C3 infection led to the formation of multinucleate cells, likely by inhibiting the actin microfilament-dependent step of cytokinesis. Intriguingly, in spite of the inhibition of cytokinesis, karyokinesis continued, with the result that cells containing a nuclear DNA content as high as 16N (eight nuclei) were observed. In addition, dsSIN:C3-mediated inactivation of Rho was a potent activator of apoptosis in EL4 cells. To discern whether the formation of multinucleate cells was responsible for the activation of apoptosis, 5-fluorouracil (5-FUra) was used to induce cell cycle arrest. As expected, EL4 cells treated with 5-FUra were prevented from forming multinucleate cells upon infection with dsSIN:C3. dsSIN:C3 infection, however, still caused marked apoptosis in 5-FUra-treated cells, indicating that this activation of apoptosis was independent of multinucleate cell formation.

The requirement for proteasome activity class I major histocompatibility complex antigen presentation is dictated by the length of preprocessed antigen.

Accumulating evidence has implicated the proteasome in the processing of protein along the major histocompatibility complex (MHC) class I presentation pathway. The availability of potent proteasome inhibitors provides an opportunity to examine the role of proteasome function in antigen presentation by MHC class I molecules to CD8+ cytotoxic T lymphocytes (CTLs). We have investigated the processing and presenting of antigenic epitopes from influenza hemagglutinin in target cells treated with the inhibitor of proteasome activity MG132. In the absence of proteasome activity, the processing and presentation of the full-length hemagglutinin was abolished, suggesting the requirement for proteasome function in the processing and presentation of the hemagglutinin glycoprotein. Epitope-containing translation products as short as 21 amino acids when expressed in target cells required proteasome activity for processing and presentation of the hemagglutin epitope to CTLs. However, when endogenous peptides of 17 amino acids or shorter were expressed in target cells, the processing and presentation of epitopes contained in these peptides were insensitive to the proteasome inhibitor. Our results support the hypothesis that proteasome activity is required for the generation of peptides presented by MHC class I molecules and that the requirement for proteasome activity is dependent on the size of the translation product expressed in the target cell. The implications of these findings are discussed.

The expression of chloramphenicol acetyltransferase in Aedes albopictus (C6/36) cells and Aedes triseriatus mosquitoes using a double subgenomic recombinant Sindbis virus.

Genomic RNA was transcribed in vitro from the double subgenomic recombinant Sindbis (SIN) virus expression vector, pTE/3'2J/CAT, and transfected into BHK-21 cells to generate recombinant virus stocks. TE/3'2J/CAT virus was used to infect C6/36 (Aedes albopictus) cells and adult female Aedes triseriatus. When C6/36 cells were infected with TE/3'2J/CAT virus at a multiplicity of infection (MOI) of greater than 20, 100% of the cells expressed CAT. The number of CAT polypeptides expressed per cell at 24 h post infection (pi) was 8.3 x 10(5). Approximately 4.0 log10TCID50 of the TE/3'2J/CAT virus was intrathoracically inoculated into adult female mosquitoes. Titers greater than 6.0 log10TCID50/ml were detected within 4 days pi and declined to less than 4.0 log10TCID50/ml 20 days following inoculation. CAT activity was detected within 2 days (8 x 10(-5) units of CAT/mosquito or 1.4 x 10(10) CAT polypeptides), peaked at day 6 (4 x 10(-3) units of CAT/mosquito or 7.2 x 10(11) CAT polypeptides), and remained at peak levels to day 20. Immunofluorescence and CAT activity assays were used to localize CAT expression in infected mosquitoes and demonstrated that CAT was present in neural, midgut, ovarian, and salivary gland tissues. Alphavirus-based expression vectors should be useful for expressing heterologous genes in mosquito cells as well as adult mosquitoes.

Rubella virus-specific cytotoxic T-lymphocyte responses: identification of the capsid as a target of major histocompatibility complex class I-restricted lysis and definition of two epitopes.

The role of major histocompatibility complex (MHC) class I-restricted CD8+ cytotoxic T lymphocytes in immunity to rubella virus (RV) infection is unknown. Lymphocytes of RV-immune individuals were prestimulated on an RV-infected MHC class I-matched (or partially matched) fibroblast monolayer which generated CD8+ lymphoblasts capable of lysing RV-infected fibroblast targets in a class I-restricted manner. Using an infectious Sindbis virus (SV) vector which expressed the RV capsid protein (SV/RubC), lymphocytes from 17 of 22 RV-immune individuals prestimulated on RV-infected fibroblast monolayers lysed SV/RubC-infected fibroblast targets. A sequence within the amino terminus of the capsid protein that was previously shown to contain immunodominant class II-restricted T-cell epitopes was evaluated for class I-restricted epitopes. Fibroblast targets pulsed with synthetic peptides representing subsequences within C1 to C29 (subscripts indicate amino acid positions) were lysed effectively when the targets and effectors matched at multiple class I alleles. By limiting the number of matching class I alleles, an A2-restricted epitope was identified within C9 to C22 and an epitope that could be presented by multiple class I molecules was identified within C11 to C29. A sequence such as C1 to C29 which contains both MHC class I- and MHC class II-restricted epitopes recognized by a heterologous human population may serve as a component of an effective synthetic vaccine.

CD8+ T cell recognition of an endogenously processed epitope is regulated primarily by residues within the epitope.

Cytotoxic T lymphocytes (CTL) recognize short antigenic peptides associated with cell surface class I major histocompatibility complex (MHC) molecules. This association presumably occurs between newly synthesized class I MHC molecules and peptide fragments in a pre-Golgi compartment. Little is known about the factors that regulate the formation of these antigenic peptide fragments within the cell. To examine the role of residues within a core epitope and in the flanking sequences for the generation and presentation of the newly synthesized peptide fragment recognized by CD8+ CTL, we have mutagenized the coding sequence for the CTL epitope spanning residues 202-221 in the influenza A/Japan/57 hemagglutinin (HA). In this study over 60 substitution mutations in the epitope were tested for their effects on target cell sensitization using a cytoplasmic viral expression system. The HA202-221 site contains two overlapping subsites defined by CTL clones 11-1 and 40-2. Mutations in HA residues 204-213 or residues 210-219 often abolished target cell lysis by CTL clones 11-1 and 40-2, respectively. Although residues outside the core epitope did not usually affect the ability to be lysed by CTL clones, substitution of a Gly residue for Val-214 abolished lysis by clone 11-1. These data suggest that residues within a site that affect MHC binding and T cell receptor recognition appear to play the predominant role in dictating the formation of the antigenic complex recognized by CD8+ CTL, and therefore the antigenicity of the protein antigen presented to CD8+ T cells. Most alterations in residues flanking the endogenously expressed epitope do not appreciably affect the generation and recognition of the site.

The efficient intracellular sequestration of the insulin-regulatable glucose transporter (GLUT-4) is conferred by the NH2 terminus.

GLUT-4 is the major facilitative glucose transporter isoform in tissues that exhibit insulin-stimulated glucose transport. Insulin regulates glucose transport by the rapid translocation of GLUT-4 from an intracellular compartment to the plasma membrane. A critical feature of this process is the efficient exclusion of GLUT-4 from the plasma membrane in the absence of insulin. To identify the amino acid domains of GLUT-4 which confer intracellular sequestration, we analyzed the subcellular distribution of chimeric glucose transporters comprised of GLUT-4 and a homologous isoform, GLUT-1, which is found predominantly at the cell surface. These chimeric transporters were transiently expressed in CHO cells using a double subgenomic recombinant Sindbis virus vector. We have found that wild-type GLUT-4 is targeted to an intracellular compartment in CHO cells which is morphologically similar to that observed in adipocytes and muscle cells. Sindbis virus-produced GLUT-1 was predominantly expressed at the cell surface. Substitution of the GLUT-4 amino-terminal region with that of GLUT-1 abolished the efficient intracellular sequestration of GLUT-4. Conversely, substitution of the NH2 terminus of GLUT-1 with that of GLUT-4 resulted in marked intracellular sequestration of GLUT-1. These data indicate that the NH2-terminus of GLUT-4 is both necessary and sufficient for intracellular sequestration.

Free vascularized fibula grafting for the treatment of osteonecrosis of the femoral head.

A variety of joint-preserving operations have been devised to preserve the necrotic femoral head with varying success. Since 1979, the authors studied the effectiveness of vascularized fibula grafting in the treatment of osteonecrosis of the femoral head (ONFH) for joint preservation. Eighty-one of 121 hips with a minimum follow-up period ranged from three years to ten years eight months (mean, five years two months). All patients were evaluated clinically and roentgenographically on the basis of the causes and the stages of the disease. In the clinical assessment, 60 (74%) of 81 hips were rated excellent, 14 (17%) were rated good, six (7%) were rated fair, and one (2%) was rated poor. Overall satisfactory results, including excellent and good, were seen in 74 hips (91%). In the roentgenographic assessment, 57 hips (71%) had improved radiologically, 15 (18%) were unchanged, and nine (11%) were worse. Seventy-two hips (89%) showed roentgenographic improvement or unchange. Roentgenographic results had no significant correlation with the etiologic factors. Vascularized fibula grafting is one of the better alternatives for treating ONFH. It is highly expected that vascularized fibula grafting can prevent the necrotic femoral head from progressing to collapse and promote directly restored vascularization and new bone formation.

Infectious Sindbis virus transient expression vectors for studying antigen processing and presentation.

Sindbis virus (SIN) is a small positive-strand enveloped RNA virus that infects a broad range of vertebrate and insect cells. A SIN vector (called dsSIN), designed for transient expression of heterologous RNAs and proteins, was engineered by inserting a second subgenomic mRNA promoter sequence into a nonessential region of the SIN genome. By using this vector, dsSIN recombinants have been constructed that express either bacterial chloramphenicol acetyltransferase, a truncated form of the influenza hemagglutinin (HA), or mini-genes encoding two distinct immunodominant cytotoxic T lymphocyte (CTL) HA epitopes. Infection of murine cell lines with these recombinants resulted in the expression of approximately 10(6)-10(7) chloramphenicol acetyltransferase polypeptides per cell and efficient sensitization of target cells for lysis by appropriate major histocompatibility complex-restricted HA-specific CTL clones in vitro. In addition, priming of an influenza-specific T-cell response was observed after immunizing mice with dsSIN recombinants expressing either a truncated form of HA or the immunodominant influenza CTL epitopes. This SIN expression system allows the generation of high-titered recombinant virus stocks in a matter of days and should facilitate mapping and mutational analysis of class I major histocompatibility complex-restricted T-cell epitopes expressed via the endogenous pathway of antigen processing and presentation.