Exposure to medium and high ambient levels of ozone causes adverse systemic inflammatory and cardiac autonomic effects

Epidemiological evidence suggests that exposure to ozone increases cardiovascular morbidity. However, the specific biological mechanisms mediating ozone-associated cardiovascular effects are unknown. To determine whether short-term exposure to ambient levels of ozone causes changes in biomarkers of cardiovascular disease including heart rate variability (HRV), systemic inflammation, and coagulability, 26 subjects were exposed to 0, 100, and 200 ppb ozone in random order for 4 h with intermittent exercise. HRV was measured and blood samples were obtained immediately before (0 h), immediately after (4 h), and 20 h after (24 h) each exposure. Bronchoscopy with bronchoalveolar lavage (BAL) was performed 20 h after exposure. Regression modeling was used to examine dose-response trends between the endpoints and ozone exposure. Inhalation of ozone induced dose-dependent adverse changes in the frequency domains of HRV across exposures consistent with increased sympathetic tone [increase of (parameter estimate ± SE) 0.4 ± 0.2 and 0.3 ± 0.1 in low- to high-frequency domain HRV ratio per 100 ppb increase in ozone at 4 h and 24 h, respectively (P = 0.02 and P = 0.01)] and a dose-dependent increase in serum C-reactive protein (CRP) across exposures at 24 h [increase of 0.61 ± 0.24 mg/l in CRP per 100 ppb increase in ozone (P = 0.01)]. Changes in HRV and CRP did not correlate with ozone-induced local lung inflammatory responses (BAL granulocytes, IL-6, or IL-8), but changes in HRV and CRP were associated with each other after adjustment for age and ozone level. Inhalation of ozone causes adverse systemic inflammatory and cardiac autonomic effects that may contribute to the cardiovascular mortality associated with short-term exposure.

A high affinity recombinant antibody to the human EphA3 receptor with enhanced ADCC activity

EphA3 is expressed in solid tumors and leukemias and is an attractive target for the therapy. We have generated a panel of Humaneered® antibodies to the ligand-binding domain using a Fab epitope-focused library that has the same specificity as monoclonal antibody mIIIA4. A high-affinity antibody was selected that competes with the mIIIA4 antibody for binding to EphA3 and has an improved affinity of ∼1 nM. In order to generate an antibody with potent cell-killing activity the variable regions were assembled with human IgG1k constant regions and expressed in a Chinese hamster ovary (CHO) cell line deficient in fucosyl transferase. Non-fucosylated antibodies have been reported to have enhanced binding affinity for the IgG receptor CD16a (FcγRIIIa). The affinity of the antibody for recombinant CD16a was enhanced approximately 10-fold. This resulted in enhanced antibody-dependent cell-mediated cytotoxicity (ADCC) activity against EphA3-expressing leukemic cells, providing a potent antibody for the evaluation as a therapeutic agent.

Accelerated neuronal differentiation toward motor neuron lineage from human embryonic stem cell line (H9)

Motor neurons loss plays a pivotal role in the pathoetiology of various debilitating diseases such as, but not limited to, amyotrophic lateral sclerosis, primary lateral sclerosis, progressive muscular atrophy, progressive bulbar palsy, pseudobulbar palsy, and spinal muscular atrophy. However, advancement in motor neuron replacement therapy has been significantly constrained by the difficulties in large-scale production at a cost-effective manner. Current methods to derive motor neuron heavily rely on biochemical stimulation, chemical biological screening, and complex physical cues. These existing methods are seriously challenged by extensive time requirements and poor yields. An innovative approach that overcomes prior hurdles and enhances the rate of successful motor neuron transplantation in patients is of critical demand. Iron, a trace element, is indispensable for the normal development and function of the central nervous system. Whether ferric ions promote neuronal differentiation and subsequently promote motor neuron lineage has never been considered. Here, we demonstrate that elevated iron concentration can drastically accelerate the differentiation of human embryonic stem cells (hESCs) toward motor neuron lineage potentially via a transferrin mediated pathway. HB9 expression in 500 nM iron-treated hESCs is approximately twofold higher than the control. Moreover, iron treatment generated more matured and functional motor neuron-like cells that are ∼1.5 times more sensitive to depolarization when compared to the control. Our methodology renders an expedited approach to harvest motor neuron-like cells for disease, traumatic injury regeneration, and drug screening.

Completing records-based research within the military: a user's guide

Many of the orthopaedic studies completed within the military come from records-based research. This methodological article will assist researchers in completing such studies by highlighting the experiences and lessons learned from a recent retrospective study on amputees. Specifically, this article provides details on the various data sources available within the military, and how to access those systems, and offers general advice for the completion of retrospective studies using Department of Defense data systems. Although there are many obstacles that need to be overcome in order to successfully complete records-based research within the military, the authors hope this article will aid investigators in the completion of future projects.

Cross-talk between phosphorylation and SUMOylation regulates transforming activities of an adenoviral oncoprotein

Since the discovery of post-translational modification (PTM) by the small ubiquitin-related modifiers (SUMOs), a multitude of proteins have been described to be reversibly modified, resulting in the alteration of several cellular pathways. Interestingly, various pathogens gain access to this modification system, although the molecular mechanisms and functional consequences are barely understood. We show here that the adenoviral oncoprotein E1B-55K is a substrate of the SUMO conjugation system, which is directly linked to its C-terminal phosphorylation. This regulative connection is indispensable for modulation of the tumor suppressor p53/chromatin-remodeling factor Daxx by E1B-55K and, consequently, its oncogenic potential in primary mammalian cells. In virus infection, E1B-55K PTMs are necessary for localization to viral transcription/replication sites. Furthermore, we identify the E2 enzyme Ubc9 as an interaction partner of E1B-55K, providing a possible molecular explanation for SUMO-dependent modulation of cellular target proteins. In conclusion, these results for the first time provide evidence how E1B-55K PTMs are regulated and subsequently facilitate exploitation of the host cell SUMOylation machinery.

Wnt signaling and stem cell control

In many contexts, self-renewal and differentiation of stem cells are influenced by signals from their environment, constituting a niche. It is postulated that stem cells compete for local growth factors in the niche, thereby maintaining a balance between the numbers of self-renewing and differentiated cells. A critical aspect of the niche model for stem cell regulation is that the availability of self-renewing factors is limited and that stem cells compete for these factors (Fig. 1). Consequently, the range and concentrations of the niche factors are of critical importance. Now that some of the few self-renewing factors have become identified, aspects of the niche models can be tested experimentally. In this chapter, we address mechanisms of signal regulation that take place at the level of signal-producing cells, constituting a niche for stem cells. We emphasize the biochemical properties and posttranslational modifications of the signals, all in the context of Wnt signaling. We propose that these modifications control the range of Wnt signaling and have critical roles in establishing niches for stem cells in various tissues.

Treatment of corticosteroid refractory optic neuritis in multiple sclerosis patients with intravenous immunoglobulin

BACKGROUND

Patients with severe visual loss because of optic neuritis refractory to high dose corticosteroids have limited therapeutic options. The use of intravenous immunoglobulin (IVIG) has been advocated in the past, but data are scarce. In this study, we use a protocol different from those used in other studies, with different timing and dosage.

METHODS

Consecutive patients with corticosteroid-refractive optic neuropathy were treated with IVIG and compared with control patients who received only corticosteroids in an open-label, non-randomized, controlled prospective study.

RESULTS

Twenty-three patients received treatment with IVIG and 24 matched patients who did not receive treatment with IVIG were followed as controls. All patients had visual acuity 20/400 or worse in the affected eye. There was significant improvement in the IVIG group with 18/23 (78%) subjects reaching near normal vision (20/30 or better), compared with the control group with only 3/24 (12.5%) responding similarly.

CONCLUSIONS

The use of IVIG, following corticosteroids, may be useful using the protocol described herein, with sustained pulsed dosing. A larger controlled trial is indicated to confirm these results.

Lipid-independent secretion of a Drosophila Wnt protein

Wnt proteins comprise a large class of secreted signaling molecules with key roles during embryonic development and throughout adult life. Recently, much effort has been focused on understanding the factors that regulate Wnt signal production. For example, Porcupine and Wntless/Evi/Sprinter have been identified as being required in Wnt-producing cells for the processing and secretion of many Wnt proteins. Interestingly, in this study we find that WntD, a recently characterized Drosophila Wnt family member, does not require Porcupine or Wntless/Evi/Sprinter for its secretion or signaling activity. Because Porcupine is involved in post-translational lipid modification of Wnt proteins, we used a novel labeling method and mass spectrometry to ask whether WntD undergoes lipid modification and found that it does not. Although lipid modification is also hypothesized to be required for Wnt secretion, we find that WntD is secreted very efficiently. WntD secretion does, however, maintain a requirement for the secretory pathway component Rab1. Our results show that not all Wnt family members require lipid modification, Porcupine, or Wntless/Evi/Sprinter for secretion and suggest that different modes of secretion may exist for different Wnt proteins.

Production of recombinant protein Pap31 and its application for the diagnosis of Bartonella bacilliformis infection

Tropical bartonellosis is a highly fatal epidemic and endemic infectious disease that occurs throughout the communities of the Andes Mountains in South America. The disease is caused by the facultative intracellular bacteria, Bartonella bacilliformis. The emergence of bartonellosis in new geographic areas and an increase in the number of reported cases suggest the need for a rapid test for epidemiologic study and investigation of the disease burden. The objective of this research is to develop a rapid serologic diagnostic test using recombinant antigens to overcome the limitations of the current standard IFA technique for laboratory diagnosis. Western blot analysis with patient sera of whole cell lysate separated on a 2D gel identified Pap31 as a dominant antigen. PCR primers were designed according to the sequence of ATCC strain 35685 to amplify the gene coding for Pap31 from a local isolate (HOSP 800-09, Peru). The amplicon was subsequently cloned into pET24a, adding the T7 tag, and expressed in E. coli. Patient sera with different IFA titers confirmed the diagnostic band of 31 kDa on a Western blot of SDS-PAGE. The performance of affinity-purified recombinant Pap31 (rPap31) was also evaluated in an ELISA format with 137 patient sera of known IFA titers. The range of ELISA reading from positive sera did not overlap with the range of those from negative sera, suggesting the potential application of rPap31 in both ELISA for high throughput regional hospital settings and in the construction of handheld rapid tests for rural clinical sites.

A Dedicated Wnt Secretion Factor

The Wnt family of signaling proteins mediates cell-cell communication during development. In this issue of Cell, Bänziger et al. (2006) and Bartscherer et al. (2006) identify Wntless/Evi, a multipass transmembrane protein in the secretory pathway of Wnt-producing cells that promotes Wnt secretion.

Clinical course after change of immunomodulating therapy in relapsing-remitting multiple sclerosis

We examined the clinical course after switching disease-modifying therapy (DMT) in patients with relapsing-remitting multiple sclerosis (RRMS). Eighty-five consecutive RRMS patients who received weekly interferon beta-1a (IFN beta-1a) 6 MU i.m. for at least 18 months were enrolled. Baseline annualized relapse rate (ARR) for the 2 years prior to initiating therapy with IFN beta-1a was obtained from charts. All 85 patients received treatment with IFN beta-1a at 6 MU i.m. weekly for 18-24 months (mean 19.7 months). Treatment with IFN beta-1a reduced the mean ARR from 1.41 to 1.23 (P=0.005). All 85 patients were then switched to glatiramer acetate (GA) 20 mg s.c. daily and prospectively followed up for 36-42 months (mean 37.5 months). Patients were switched because of persistent clinical disease activity (n=62) or persistently unacceptable toxicity (n=23) as determined by the treating neurologist. Treatment with GA reduced the mean ARR from 1.23 to 0.53 (P=0.0001). Subgroup analysis showed that in patients who were switched because of lack of efficacy (n=62), the mean ARR was reduced from 1.32 on IFN beta-1a to 0.52 on GA (P=0.0001). In contrast, in patients who switched because of persistent toxicity (n=23), the mean ARR was reduced from 0.61 on IFN beta-1a to 0.47 on GA (P, non-significant). Our observations suggest that clinical observations such as relapse rate and tolerability may be used as criteria for switching DMT in clinical practice. More definitive consensus criteria incorporating magnetic resonance imaging and clinical observations for defining optimal response and tolerability need to be developed for the routine clinical management of RRMS patients receiving DMT.

Axonal metabolic recovery and potential neuroprotective effect of glatiramer acetate in relapsing-remitting multiple sclerosis

Glatiramer acetate (GA) is a disease-modifying therapy for relapsing-remitting multiple sclerosis (RRMS) with several putative mechanisms of action. Currently, there is paucity of in vivo human data linking the well-established peripheral immunologic effects of therapy with GA to its potential effects inside the central nervous system (CNS). Brain proton magnetic resonance spectroscopy (MRS) allows in vivo examination of axonal integrity by quantifying the resonance intensity of the neuronal marker N-acetylaspartate (NAA). In a pilot study to investigate the effect of GA on axonal injury, we performed combined brain magnetic resonance imaging (MRI) and MRS studies in 18 treatment naïve RRMS patients initiating therapy with GA at baseline and annually for two years on therapy. A small group of four treatment naïve RRMS patients, electing to remain untreated, served as controls. NAA/Cr was measured in a large central brain volume of interest (VOI) as well as the normal appearing white matter (NAWM) within the VOI. After two years, NAA/Cr in the GA-treated group increased significantly by 10.7% in the VOI (2.17 +/- 0.26 versus 1.96 +/- 0.24, P = 0.03) and by 71% in the NAWM (2.23 +/- 0.26 versus 2.08 +/- 0.31, P = 0.04). In the untreated group, NAA/Cr decreased by 8.9% at two years in the VOI (2.01 +/- 0.16 versus 1.83 +/- 0.21, P = 0.03) and 8.2% in the NAWM (2.07 +/- 0.24 versus 1.90 +/- 0.29, P = 0.03). Our data shows that treatment with GA leads to axonal metabolic recovery and protection from sub-lethal axonal injury. These results support an in situ effect of GA therapy inside the CNS and suggest potential neuroprotective effects of GA.

Intercaudate nucleus ratio as a linear measure of brain atrophy in multiple sclerosis

Intercaudate nucleus ratio (ICR) is a linear measure of brain atrophy that does not require software application and is independent of image acquisition techniques. The authors examined the relationship between ICR and disability in 190 patients with MS. The results show that ICR correlates with Expanded Disability Status Scale score (r = 0.67; p = 0.0001) and disease duration (r = 0.32; p < 0.01). Intercaudate ratio appears to be a reliable and reproducible linear measure of brain atrophy and correlates with disability and disease duration in MS.

Disruption of segmental neural crest migration and ephrin expression in delta-1 null mice

Neural crest cells migrate segmentally through the rostral half of each trunk somite due to inhibitory influences of ephrins and other molecules present in the caudal-half of somites. To examine the potential role of Notch/Delta signaling in establishing the segmental distribution of ephrins, we examined neural crest migration and ephrin expression in Delta-1 mutant mice. Using Sox-10 as a marker, we noted that neural crest cells moved through both rostral and caudal halves of the somites in mutants, consistent with the finding that ephrinB2 levels are significantly reduced in the caudal-half somites. Later, mutant embryos had aberrantly fused and/or reduced dorsal root and sympathetic ganglia, with a marked diminution in peripheral glia. These results show that Delta-1 is essential for proper migration and differentiation of neural crest cells. Interestingly, absence of Delta-1 leads to diminution of both neurons and glia in peripheral ganglia, suggesting a general depletion of the ganglion precursor pool in mutant mice.

Axon-glia interactions and the domain organization of myelinated axons requires neurexin IV/Caspr/Paranodin

Myelinated fibers are organized into distinct domains that are necessary for saltatory conduction. These domains include the nodes of Ranvier and the flanking paranodal regions where glial cells closely appose and form specialized septate-like junctions with axons. These junctions contain a Drosophila Neurexin IV-related protein, Caspr/Paranodin (NCP1). Mice that lack NCP1 exhibit tremor, ataxia, and significant motor paresis. In the absence of NCP1, normal paranodal junctions fail to form, and the organization of the paranodal loops is disrupted. Contactin is undetectable in the paranodes, and K(+) channels are displaced from the juxtaparanodal into the paranodal domains. Loss of NCP1 also results in a severe decrease in peripheral nerve conduction velocity. These results show a critical role for NCP1 in the delineation of specific axonal domains and the axon-glia interactions required for normal saltatory conduction.

Antibodies to phosphatidylethanolamine and phosphatidylserine are associated with increased natural killer cell activity in non-male factor infertility patients

Antiphospholipid antibodies (APA) have been identified in patients with recurrent pregnancy loss and IVF failure. Of these, antiphosphatidylethanolamine (aPE) and antiphosphatidylserine (aPS) may have special significance. A link between increased natural killer cell activity (NKa+) and trophoblast cell apoptosis has also been reported. This study was undertaken to determine how the APA profile was associated with peripheral NK cell activity. We evaluated 197 female IVF candidates for APA and NKa. Eighty-nine patients (45%) were APA+ and of these, 51 (57%) were aPE/aPS+. Fifty-four patients (27%) had increased NK cell activity. Some 51% of APA+ and 78% of aPE/aPS+ patients had increased NK cell activity compared with 8% and 13% when APA and aPE/aPS tested negative respectively (P: < 0.0001). Non-male factor infertility patients were APA+ and NKa+ in 57% and 34% of cases respectively, compared with 19% and 13% if a pure male factor was present. Some 88% of aPE/aPS+, non-male factor patients had increased NK cell activity, compared with 12% who tested aPE/aPS negative (P: < 0.0001) and 25% of aPE/aPS+, isolated male factor patients (P: < 0.0001). These findings establish a direct relationship between APA (specifically aPE/aPS) and increased peripheral NK cell activity among non-male factor infertility patients. It is possible that APA do not directly cause reproductive failure but rather function as markers or intermediaries for an underlying, abnormal activation of cellular immunity.

Clustering of neuronal sodium channels requires contact with myelinating Schwann cells

Efficient and rapid conduction of action potentials by saltatory conduction requires the clustering of voltage-gated sodium channels at nodes of Ranvier. This clustering results from interactions between neurons and myelinating glia, although it has not been established whether this glial signal is contact-dependent or soluble. To investigate the nature of this signal, we examined sodium channel clustering in co-cultures of embryonic rat dorsal root ganglion neurons and Schwann cells. Cultures maintained under conditions promoting or preventing myelination were immunostained with antibodies against the alpha subunit of the sodium channel and against ankyrin(G), a cytoskeletal protein associated with these channels. Consistent with previous in vivo studies (Vabnick et al., 1996), sodium channels and ankyrin G cluster at the onset of myelination. These clusters form adjacent to the ends of the myelinating Schwann cells and appear to fuse to form mature nodes. In contrast, sodium channels and ankyrin G do not cluster in neurons grown alone or in co-cultures where myelination is precluded by growing cells in defined media. Conditioned media from myelinating co-cultures also failed to induce sodium channel or ankyrin G clusters in cultures of neurons alone. Finally, no clusters develop in the amyelinated portions of suspended fascicles of dorsal root ganglia explants despite being in close proximity to myelinated segments in other areas of the dish. These results indicate that clustering of sodium channels requires contact with myelinating Schwann cells.

Correlation between beta 2-glycoprotein antibodies and antiphospholipid antibodies in patients with reproductive failure

PROBLEM

Antiphospholipid antibodies (APAs) are important in the etiology of reproductive failure. Studies have shown that binding proteins are necessary for the detection of APAs. One of these, beta 2-glycoprotein, has been shown to be necessary for detection of anticardiolipin antibodies. It is felt that some APAs may be directed to the binding protein itself, or to a combination of the binding protein and phospholipid.

METHOD OF STUDY

In this study, a comparison of APAs vs. anti beta 2-glycoprotein antibodies was performed on the sera of 123 women younger than 40 years of age with a history of reproductive failure. Antibodies to six phospholipid epitopes, cardiolipin, phosphatidyle-thanolamine, phosphatidylserine, phosphatidylinositol, phosphatidic acid, phosphatidylglycerol, and phosphatidylserine, were measured.

RESULTS

Of the 123 women tested, 33 had one or more positive immunoglobulin (Ig)G antibodies to phospholipids, of which 9 were to cardiolipin. However, only 1 of 123 women had IgG antibodies to beta 2-glycoprotein and she was APA negative. Thirty-eight of 123 women had one or more IgM antibodies to phospholipids, with none directed to cardiolipin IgM. In contrast, only 8 of the 123 women had IgM antibodies to beta 2-glycoprotein. Five of the eight patients had IgM APA; 4 of 5 had IgM antibodies to PE, 1 to PI.

CONCLUSIONS

There is no correlation between beta 2-glycoprotein antibodies and APA status in this population. To date, our most sensitive test for detecting phospholipid autoimmune-mediated in vitro fertilization failure still appears to be the ELISA assay for APA.

The selective use of heparin/aspirin therapy, alone or in combination with intravenous immunoglobulin G, in the management of antiphospholipid antibody-positive women undergoing in vitro fertilization

PROBLEM

The effect of mini-dose heparin/aspirin (H/A) alone vs. combined intravenous immunoglobulin G (IVIg) and H/A on in vitro fertilization (IVF) birthrates in women who test seropositive for antiphospholipid antibodies (APA+) was evaluated, as was the question of whether outcome is influenced by the gammaglobulin isotype(s) or the phospholipid (PL) epitope(s) to which the APAs are directed.

METHOD OF STUDY

A case-control study was conducted in three phases, spanning a 4-year period, in a multicenter clinical research environment. Six hundred eighty-seven APA+ women, who were younger than 40 years and who each, completed up to three consecutive IVF/embryo transfer cycles within a 12-month period, were given either H/A alone or H/A in combination with IVIg. Birthrates relative to the type of immunotherapy (i.e., H/A alone and H/A with IVIg) and APA profile were the main outcome measurements.

RESULTS

In phase I, 687 women who tested APA+ to one or more PL epitopes underwent two or fewer IVF attempts for a total of 1050 IVF cycles. Four hundred seventy-seven (46%) births occurred in 923 IVF cycles in which H/A alone was administered. Twenty-two (17%) births occurred after 127 IVF cycles in which H/A was not administered. In phase II, 322 of 687 women tested positive for a single APA subtype. These subjects underwent up to two consecutive IVF attempts for a total of 521 IVF cycles while receiving H/A alone. The birthrate was significantly lower for women whose APAs were directed toward phosphatidylethanolamine (PE) or phosphatidylserine (PS) involving IgG or IgM isotypes than for women who had any other APA (17% vs. 43%). In phase III, 121 women who did not achieve live births after two consecutive IVF attempts in which H/A alone was administered received IVIg in combination with H/A during their third consecutive IVF cycle. The birth rate was 41% after these IVF cycles when anti-PS or anti-PE involving IgG or IgM isotypes were present, as compared with 17% when H/A alone was administered. The IVF outcome did not improve when IVIg was administered in association with any other single APA.

CONCLUSIONS

The treatment of APA+ women with H/A alone improves IVF birthrates. This benefit is selective in that it does not apply in cases in which IgG- or IgM-related APAs are directed against PE or PS. In such cases, the addition of IVIg significantly improves the outcome.

A rational basis for the use of combined heparin/aspirin and IVIG immunotherapy in the treatment of recurrent IVF failure associated with antiphospholipid antibodies

PROBLEMS

1) Does the administration of heparin and aspirin (H/A) in combination with intravenous immunoglobulin G (IVIG) improve in vitro fertilization (IVF) implantation and birth rates in patients with recurrent IVF failure? 2) Is the effect of such treatment related to the antiphospholipid antibody (APA) status of the patients concerned?

METHOD OF STUDY

Subjects consisted of 89 women younger than 36 years of age whose infertility was a result of causes other than male infertility and who had experienced four or more failed IVF/embryo transfer procedures. Fifty-two women were APA+ (group A), and 37 were APA- (group B). All patients, regardless of their APA status, received H/A (5000 U sq bid), aspirin (81 mg po qd) from the inception of menotropin therapy along with IVIG (20 g) through a single infusion 3 to 10 days before egg retrieval.

RESULTS

Twenty-two (42%) of group A and 7 (19%) of group B patients achieved live births (P = 0.020).

CONCLUSIONS

IVF outcome is significantly improved when H/A and IVIG are administered to APA+ women with repeat IVF failures. APA- women do not seem to benefit from such treatment.

The use of combined heparin/aspirin and immunoglobulin G therapy in the treatment of in vitro fertilization patients with antithyroid antibodies

PROBLEM

To compare the effect of heparin/aspirin therapy alone vs. heparin/aspirin in combination with intravenous immuno-globulin (IVIg) immunotherapy on in vitro fertilization (IVF) outcome of patients who test positive for antithyroid antibodies (ATAs).

METHOD OF STUDY

Eighty-two women younger than 40 years of age whose infertility was related exclusively to female causes were evaluated. All tested positive for organ-specific antithyroid antibodies (antimicrosomal and/or antithyroglobulin antibodies), but negative for antiphospholipid antibodies. Thirty-seven of these women (group A) received H/A alone, whereas 45 (group B) received heparin/aspirin in combination with IVIg.

RESULTS

Ten (27%) of women in group A and 23 (51%) of women in group B achieved live births after completion of a single IVF/embryo transfer cycle (P = 0.027).

CONCLUSION

We conclude that IVIg therapy significantly improves IVF success rates in ATA+ women.

The axonal membrane protein Caspr, a homologue of neurexin IV, is a component of the septate-like paranodal junctions that assemble during myelination

We have investigated the potential role of contactin and contactin-associated protein (Caspr) in the axonal-glial interactions of myelination. In the nervous system, contactin is expressed by neurons, oligodendrocytes, and their progenitors, but not by Schwann cells. Expression of Caspr, a homologue of Neurexin IV, is restricted to neurons. Both contactin and Caspr are uniformly expressed at high levels on the surface of unensheathed neurites and are downregulated during myelination in vitro and in vivo. Contactin is downregulated along the entire myelinated nerve fiber. In contrast, Caspr expression initially remains elevated along segments of neurites associated with nascent myelin sheaths. With further maturation, Caspr is downregulated in the internode and becomes strikingly concentrated in the paranodal regions of the axon, suggesting that it redistributes from the internode to these sites. Caspr expression is similarly restricted to the paranodes of mature myelinated axons in the peripheral and central nervous systems; it is more diffusely and persistently expressed in gray matter and on unmyelinated axons. Immunoelectron microscopy demonstrated that Caspr is localized to the septate-like junctions that form between axons and the paranodal loops of myelinating cells. Caspr is poorly extracted by nonionic detergents, suggesting that it is associated with the axon cytoskeleton at these junctions. These results indicate that contactin and Caspr function independently during myelination and that their expression is regulated by glial ensheathment. They strongly implicate Caspr as a major transmembrane component of the paranodal junctions, whose molecular composition has previously been unknown, and suggest its role in the reciprocal signaling between axons and glia.

A comparison of flow cytometry and microcytotoxicity for the evaluation of alloimmune therapy in patients with recurrent spontaneous abortions

PROBLEM

There is substantial data that support the efficacy of paternal leukocyte immunization (PLI) for the treatment of alloimmune mediated miscarriage; however, there is confusion regarding the laboratory test that should be performed to determine levels of maternal anti-paternal leukocyte antibodies (MAPLA).

METHOD

Popular methodologies employed include: 1) microcytotoxicity (MCX), 2) mixed lymphocyte culture (MLC), and 3) cell flow cytometry crossmatch (FCXM). Cell flow cytometry crossmatch correlates well with the more difficult MLC assay although the former proves the more sensitive study. This work compares the MCX assays with FCXM. The study group consisted of ten women who had a history of three or more spontaneous abortions (SABs). All ten had very low levels (< 10%) of MAPLA as measured by FCXM. Following PLI all subjects demonstrated elevated levels (> 50%) of MAPLA by FCXM. At 12 weeks gestation, sera were simultaneously measured for MAPLA by MCX and FCXM.

RESULTS

Although all ten patients had very high levels of MAPLA by FCXM during pregnancy, five of ten had antibodies to HLA Class I and two of ten had antibodies to HLA Class II paternal antigens by MCX. Furthermore, all patients who were positive by MCX to paternal Class I antigens were also positive to Class I antigens not seen in either parent. Both patients who were positive by MCX to paternal Class II antigens were also positive to maternal Class II antigens. Notable is that all ten women eventually delivered healthy infants.

CONCLUSION

Based on this preliminary study, the MCX assay is neither sensitive or reliable enough to determine the need and/or to monitor the effectiveness of PLI. Flow cytometry should be the modality of choice when determining the need for alloimmunotherapy and to monitor the effectiveness of treatment.

High fecundity rates following in-vitro fertilization and embryo transfer in antiphospholipid antibody seropositive women treated with heparin and aspirin

This study was undertaken to explore whether intervention with heparin and aspirin (H/A) in selected patients undergoing in-vitro fertilization (IVF) and embryo transfer could improve fecundity rates. Specifically, it explored the possibility that women diagnosed with organic pelvic disease who demonstrated antiphospholipid antibodies (APA) could benefit from H/A administration in a similar manner to that used in patients with recurrent pregnancy loss. We used an enzyme-linked immunosorbent assay for six different phospholipids to identify patients who expressed APA before they underwent IVF/embryo transfer. This study was confined to the first IVF/embryo transfer cycle that followed assessment of APA status and accordingly, the number of IVF/embryo transfer cycles corresponds with the number of patients treated. APA seropositive patients were treated with aspirin, 81 mg orally q.d., and heparin 5000 IU s.c. b.i.d., beginning on day 1 of controlled ovarian stimulation. The endpoint for success was a live birth or an ultrasound confirming fetal cardiac activity (a viable pregnancy). The prevalence of APA in patients diagnosed with organic pelvic disease (53%) was much higher than in those without female pathology (14%). The administration of H/A to APA seropositive patients significantly (P < 0.05) improved the viable pregnancy rate (49%) compared to the untreated APA seropositive group (16%). The viable pregnancy rate for APA seropositive women treated with H/A was also significantly (P < 0.001) higher than for untreated APA seronegative patients (27%). We conclude that all women undergoing IVF/embryo transfer should be tested for APA prior to initiating ovarian stimulation and those with APA seropositivity should be treated with H/A.

Characterization of antiphospholipid antibodies in women with recurrent spontaneous abortions

Antiphospholipid antibodies are important in the etiology of recurrent pregnancy loss. To date, most studies have concentrated on antibodies to cardiolipin specifically. In this study, the serum of 352 women with recurrent pregnancy loss was studied by enzyme-linked immunosorbent assay for antibodies to six phospholipid epitopes: cardiolipin, phosphoserine, phosphoglycerol, phosphoethanolamine, phosphatidic acid and phosphoinositol. Of these women, 59.1% had either an IgG or IgM antibody to one of the six phospholipids. This compared to only 4.6% in the control group. Approximately 75% of the isotypes were IgM. The most common phospholipid epitope was phosphoserine. However, in patients with antibodies to only one phospholipid, phosphoethanolamine was the most common. These findings support recent evidence that antiphospholipid antibodies may interfere with the formation of syncytiotrophoblasts in the placenta. In addition, antiphospholipid antibodies occur more frequently in patients who suffer recurrent miscarriages than was previously thought.

Age-dependent extrasynaptic modulation of axonal conduction by exogenous and endogenous GABA in the rat optic nerve

To ascertain whether endogenous gamma-aminobutyric acid (GABA) exists and exerts physiological effects in the optic nerve, we compared the effects of GABA and related drugs on the neonatal (1 to 22 days of age) and adult (greater than 6 months) rat optic nerve in vitro. GABA (10(-4)-10(-3) M) reversibly depressed the amplitude and increased the latency of compound action potentials in the neonatal optic nerve. In the adult optic nerve, GABA (10(-4)-10(-3) M) had no significant effect on the compound action potential. The GABA-A receptor agonist, isoguvacine (10(-4)-10(-3) M), mimicked these GABA effects on the neonate and adult optic nerve. Lower concentrations (10(-5) M) of GABA increased excitability of the neonatal optic nerve but produced no discernible effects on the adult optic nerve. The GABA-uptake inhibitor, nipecotic acid (10(-3) M), mimicked the effects of GABA (10(-5) M) on the neonatal optic nerve. The GABA-A receptor blockers, picrotoxin and bicuculline (10(-6)-10(-3) M), decreased the latency of compound action potentials in the neonatal optic nerve. Membrane potential recordings indicate that while GABA (10(-5)-10(-3) M) depolarized the neonatal optic nerve dose-dependently, picrotoxin hyperpolarized the axons. In the adult optic nerve, neither GABA-uptake inhibitors nor GABA-A receptor blockers had significant effects on the compound action potential. These results suggest that functional GABA-A receptors and GABA are present in the neonatal rat optic nerve and depolarize axons under physiological conditions. However, this does not appear to be the case in the adult optic nerve.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of silicon nitride ceramic on rabbit skeletal cells and tissue. An in vitro and in vivo investigation

This article presents a morphologic assessment of the effect of silicon nitride ceramic (Si3N4) on rabbit marrow stromal cells and their differentiation when grown in vitro and in vivo. In vitro marrow stromal cells (MSC) attached initially to upper portions of ceramic discs. However, at four weeks, cells only attached to disc edges. Fresh marrow or first passage MSC, inoculated into diffusion chambers with and without Si3N4, formed cartilage, bone, and fibrous tissue after being implanted intraperitoneally for five weeks. Tissue differentiated adjacent to Si3N4 but not within the pores. In contrast, Si3N4 implants inserted into femoral marrow cavities were surrounded initially by woven bone and within three months by mature bone that had permeated implants with a pore size of 255 +/- 64 microns. Plugs having a pore diameter of 170 +/- 45 microns mainly contained vascularized fibrous tissue with occasional foci of osteoid or bone in the peripheral pores. In a pilot experiment, three femoral segmental Si3N4 endoprostheses were implanted in three adult rabbits, and the osseous reactions were monitored during their natural life. Each implant was enclosed by a stable cuff of bone within four months of implantation and remained unchanged during the rest of the animal's life. Autopsies confirmed these roentgenographic observations, and tissue appositional to each prosthesis was morphologically normal. Si3N4 has the potential of an important ceramic for use in osseous reconstruction.

Growth of bone marrow cells on porous ceramics in vitro

Following the transplantation of bone marrow cells to extra-osseous sites, bone formation occurs in those sites. This osteogenic potential of bone marrow cells might be utilized for filling defects in bone if they could be transported on porous ceramic materials. Before such an approach becomes feasible, it is important to know what happens to the cells in the presence of the ceramics that might be used. In order to investigate the interaction between bone marrow cells and ceramics, in vitro, a system for culturing bone marrow cells on ceramic materials has been developed. Bone marrow cells adhered well to the surface of calcium hydroxyapatite and tricalcium phosphate ceramics, and this was followed by the formation of fibrous tissue on and within the ceramics. These ceramics were compatible with bone marrow cells even in culture conditions in which there was a large surface area of ceramic interfacing with cells. The results support the proposal that calcium hydroxyapatite and tricalcium phosphate are appropriate as bone replacement materials. In contrast, calcium aluminate had an adverse effect on bone marrow cells when there was a high proportion of ceramic to culture medium. However, this effect was not present if the proportion of ceramic to culture medium was low. Therefore, a large amount of biodegradable porous calcium aluminate ceramic should not be used as an alternative to autogeneous bone grafting.

Bone ingrowth into three different porous ceramics implanted into the tibia of rats and rabbits

Three different porous ceramics--calcium aluminate, calcium hydroxyapatite, and tricalcium phosphate--were implanted into the proximal tibia in rats and rabbits to study the interactions between these ceramics and a bony site that is abundant in bone marrow. New bone was consistently formed within the bone marrow surrounding and adjacent to all three types of ceramics. Calcium hydroxyapatite and tricalcium phosphate ceramics permitted bone ingrowth into their pores. The newly formed bone was found only in the part of the ceramic intruding into the bone, not in the portion protruding in the soft tissues outside the tibia. Partial replacement of the new bone opposite the medullary portion by new hemopoietic marrow occurred with longer implantation times. In contrast, no bone was seen within the pores of any of the calcium aluminate implants.

The use of ceramics for bone replacement. A comparative study of three different porous ceramics

Ceramics have many properties which might make them suitable alternatives to bone grafts. This present study was done to find a suitable biodegradable porous ceramic for human bone replacement. Three different porous ceramics (calcium aluminate, calcium hydroxyapatite and tricalcium phosphate), with interlinked pores of two size ranges (150 to 210 micron), were implanted into the skulls of rats and rabbits for up to six months; the interaction with surrounding bone, which is virtually devoid of bone marrow, was then assessed. The ceramics caused no adverse biological response. Tissue ingrowth into pores throughout the implant was seen in all three types and in both pore sizes of ceramic, but the density of the penetrating tissue was far less for calcium aluminate than for calcium hydroxyapatite or tricalcium phosphate. For each type of ceramic, the soft-tissue ingrowth was more dense with the larger pore size, and with a longer period of implantation. Bone ingrowth was not usually seen within the pores of any ceramic. There were no differences in the histological findings between the rats and the rabbits. The results demonstrate that it is possible to produce ceramic materials with a porous structure which allows ingrowth of tissue and biological fluids.