Pilot study: placental biomarker predictive capability (sFlt-1, PlGF and their ratio) of postpartum maternal outcome.

BACKGROUND: Prenatal measurement of placental biomarkers was able to improve screening and diagnosis of preeclampsia. Little is known about the clinical role of placental biomarkers in the postpartum period. METHODS: This study is a prospective monocentric trial that included a total of 30 women with preeclamptic pregnancies. Serum placental biomarkers including soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF) were measured before and 2 h after delivery by Enzyme-Linked Immunosorbent Assay (ELISA) using commercially available kits according to manufacturer's instructions and correlated with the postpartum outcome. RESULTS: Postpartum higher serum PlGF level was associated with postpartum elevation of the systolic blood pressure. Yet, the placental biomarkers were not able to predict general worsening of postpartum preeclampsia or other individual clinical or laboratory parameters. CONCLUSION: Serum concentrations of sFlt-1 and PlGF or their ratio in our study cohort did not completely predict the occurrence of postpartum preeclampsia. Yet, postpartum higher serum PlGF level was associated with postpartum elevation of the systolic blood pressure.

What causes mating system shifts in plants? Arabidopsis lyrata as a case study.

The genetic breakdown of self-incompatibility (SI) and subsequent mating system shifts to inbreeding has intrigued evolutionary geneticists for decades. Most of our knowledge is derived from interspecific comparisons between inbreeding species and their outcrossing relatives, where inferences may be confounded by secondary mutations that arose after the initial loss of SI. Here, we study an intraspecific breakdown of SI and its consequences in North American Arabidopsis lyrata to test whether: (1) particular S-locus haplotypes are associated with the loss of SI and/or the shift to inbreeding; (2) a population bottleneck may have played a role in driving the transition to inbreeding; and (3) the mutation(s) underlying the loss of SI are likely to have occurred at the S-locus. Combining multiple approaches for genotyping, we found that outcrossing populations on average harbour 5 to 9 S-locus receptor kinase (SRK) alleles, but only two, S1 and S19, are shared by most inbreeding populations. Self-compatibility (SC) behaved genetically as a recessive trait, as expected from a loss-of-function mutation. Bulked segregant analysis in SC × SI F2 individuals using deep sequencing confirmed that all SC plants were S1 homozygotes but not all S1 homozygotes were SC. This was also revealed in population surveys, where only a few S1 homozygotes were SC. Together with crossing data, this suggests that there is a recessive factor that causes SC that is physically unlinked to the S-locus. Overall, our results emphasise the value of combining classical genetics with advanced sequencing approaches to resolve long outstanding questions in evolutionary biology.

Use of quantum effects as potential qualifying metrics for "quantum grade silicon".

Across solid state quantum information, materials deficiencies limit performance through enhanced relaxation, charge defect motion or isotopic spin noise. While classical measurements of device performance provide cursory guidance, specific qualifying metrics and measurements applicable to quantum devices are needed. For quantum applications, new materials metrics, e.g., enrichment, are needed, while existing, classical metrics like mobility might be relaxed compared to conventional electronics. In this work, we examine locally grown silicon superior in enrichment, but inferior in chemical purity compared to commercial-silicon, as part of an effort to underpin the materials standards needed for quantum grade silicon and establish a standard approach for intercomparison of these materials. We use a custom, mass-selected ion beam deposition technique, which has produced isotopic enrichment levels up to 99.99998 % 28Si, to isotopically enrich 28Si, but with chemical purity > 99.97% due the MBE techniques used. From this epitaxial silicon, we fabricate top-gated Hall bar devices simultaneously on the 28Si and on the adjacent natural abundance Si substrate for intercomparison. Using standard-methods, we measure maximum mobilities of ≈(1740±2)cm2/(V⋅s) at an electron density of (2.7×1012±3×108) cm-2 and ≈(6040±3)cm2/(V⋅s) at an electron density of (1.2×1012±5×108) cm-2 at T=1.9 K for devices fabricated on 28Si and natSi, respectively. For magnetic fields B>2 T, both devices demonstrate well developed Shubnikov-de Haas (SdH) oscillations in the longitudinal magnetoresistance. This provides transport characteristics of isotopically enriched 28Si, and will serve as a benchmark for classical transport of 28Si at its current state, and low temperature, epitaxially grown Si for quantum devices more generally.

Structure and function of the C-terminal hypervariable region of K-Ras4B in plasma membrane targetting and transformation.

The C-terminal hypervariable domain of K-Ras4B targets the protein to the plasma membrane by a combination of positive charge and a hydrophobic signal (farnesyl group). We analysed the contribution of several structural features of the domain: net charge, charge distribution, amino acid sequence and lipid specificity to membrane targetting and function by using artificial 'hypervariable' domains fused to either EGFP or V12KRas4B. We found that charge and a lipid residue are sufficient for plasma membrane localization and function of the constitutively active V12K-Ras4B. However, the amount of net charge, charge distribution and the length of the anchoring domain are important. Increasing the net charge and concentrating it close to the C-terminus increases not only the percentage of membrane bound protein, but also shifts the distribution from internal membranes, including the nuclear envelope, to the plasma membrane. While plasma membrane binding is necessary for V12K-Ras4B activity (MAPK activation and focus formation), we found that there are additional restrictions. In particular, mutants with very highly charged domains that bind almost exclusively to the plasma membrane show less transforming potential than expected. In addition, a construct with a short 'hypervariable' domain (7 amino acids) also has decreased transformation activity. These results suggest that specific interactions between K-Ras4B and the plasma membrane are required.

Detergent extraction of cholera toxin and gangliosides from cultured cells and isolated membranes.

Choleragen, when bound to various cultured cells, resisted extraction by Triton X-100 under conditions which retained the cytoskeletal framework of the cells. The resistance (greater than 75% of the bound toxin) was observed in Friend erythroleukemic, mouse neuroblastoma N18 and NB41A and rat glioma C6 cells even though the different cells varied over 1000-fold in the number of toxin receptors. The extent of extraction did not depend on whether the cells were in monolayer culture of in suspension or whether choleragen was found at 0 or 37 degrees C. A similar resistance to extraction was also observed in membranes isolated from toxin-treated cells. Using more drastic conditions and other non-ionic detergents, 90% of the bound choleragen was solubilized from cells and membranes. When rat glioma C6 cells, which bind only small amounts of choleragen, were incubated with the ganglioside GM1, toxin binding was increased and the bound toxin was also resistant to extraction. When these cells were incubated with [3H]GM1, up to 70% of the cell-associated GM1 was extracted under the mild conditions. When the Gm1-labeled cells were incubated with choleragen or its B (binding) component, there was a significant reduction in the solubilization of GM1. Similar results were obtained with isolated membranes. When choleragen-receptor complexes were isolated from N18 cells labeled with [3H] galactose by immunoadsorption, only labeled GM1 was specifically recovered. These results suggest that it is the choleragen-ganglioside complex that is resistant to detergent extraction.

Focal motility determines the geometry of dendritic spines.

The geometry of dendritic spines has a major impact on signal transmission at excitatory synapses. To study it in detail we raised transgenic mice expressing an intrinsic green fluorescent protein-based plasma membrane marker that directly visualizes the cell surface of living neurons throughout the brain. Confocal imaging of developing hippocampal slices showed that as dendrites mature they switch from producing labile filopodia and polymorphic spine precursors to dendritic spines with morphologies similar to those reported from studies of adult brain. In images of live dendrites these mature spines are fundamentally stable structures, but retain morphological plasticity in the form of actin-rich lamellipodia at the tips of spine heads. In live mature dendrites up to 50% of spines had cup-shaped heads with prominent terminal lamellipodia whose motility produced constant alterations in the detailed geometry of the synaptic contact zone. The partial enveloping of presynaptic terminals by these cup-shaped spines coupled with rapid actin-driven changes in their shape may operate to fine-tune receptor distribution and neurotransmitter cross-talk at excitatory synapses.

Tactical combat casualty care in special operations.

U.S military medical personnel are currently trained to care for combat casualties using the principles taught in the Advanced Trauma Life Support (ATLS) course. The appropriateness of many of the measures taught in ATLS for the combat setting is unproven. A 2-year study to review this issue has been sponsored by the United States Special Operations Command. This paper presents the results of that study. We will review some of the factors that must be considered in caring for wounded patients on the battlefield with an emphasis on the Special Operations environment. A basic management protocol is proposed that organizes combat casualty care into three phases and suggests appropriate measures for each phase. A scenario-based approach is needed to plan in more detail for casualties on specific Special Operations missions, and several sample scenarios are presented and discussed.

Portable satellite telemedicine in practice.

The US army's first portable telemedicine unit was built in 1993 and comprised a 'ruggedized' videoconferencing unit. The unit was initially used in the United Nations' operations in Macedonia in February 1994 and subsequently in support of the Mobile Army Surgical Hospitals in Haiti, but its dimensions made it suitable only for locations where a move at short notice was unlikely. The second portable telemedicine unit comprised a PC linked to an Inmarsat B earth station through a modern. The unit allowed videoconferencing at 64 kbit/s. Three and a half years of clinical experience with both units has shown this to be quite adequate for the majority of clinical telemedicine. Portable telemedicine units have been a major benefit to medical commanders in the field.

Diet and cancer.

Large claims have been made for the effectiveness of particular diets in preventing cancer or inhibiting its progression. However, more recent clinical studies have not confirmed this. Instead it seems that rather than specific dietary constituents, total calories influence cancer incidence and progression. In this review article, we summarise and interpret the available evidence for links between diet and cancer.

Developmentally regulated compartmentalization of adenylate cyclase in Dictyostelium discoideum.

Adenylate cyclase of aggregation phase Dictyostelium discoideum is activated by extracellular adenosine 3', 5'-cyclic monophosphate (cAMP), and the cAMP synthesized is secreted. The distribution of the enzyme was determined in sucrose gradients loaded with whole cell lysates. Cell lysates prepared after 4.5 hr of starvation revealed membranes containing adenylate cyclase at 44% and 33% sucrose. The activity of the latter peak was detected in the presence of the detergent (CHAPS), 3-(3-cholamidopropyl) dimethylammonio-3-propanesulfonate, which inhibited the activity of the former to some extent. Adenylate cyclase activity of the 2 peaks differed with respect to solubility in CHAPS and their kinetics. The 44% sucrose region of the gradient contained the bulk of the plasma membranes, as judged by a cell surface glycoprotein marker (contact site A). The 33% peak is composed of small vesicular structures, as determined by electron microscopy. The distribution of adenylate cyclase activity detected in sucrose gradients shifted from the 33% to the 44% sucrose peak during development. In addition, the 44% peak became increasingly resistant to the inhibitory effect of CHAPS. Both changes were accelerated by extracellular cAMP, but only the latter was abolished when the production of endogenous cAMP was inhibited by caffeine. Pulsing cells with cAMP overcame the inhibitory effect of caffeine.

Pattern formation and handedness in the cytoskeleton of human platelets.

The cytoskeletal patterns of human platelets spread on a glass surface are analyzed. F-actin is arranged in patterns of parallel microfilaments, microfilaments forming triangles, or microfilaments radiating tangentially from a central ellipse or circle. Vinculin, a cytoskeletal protein, is located at both ends of the filaments. In platelets with tangentially radiating microfilaments, vinculin patches are aligned on the branches of a two-armed spiral. The spirals are always left-handed. Talin and two integrins (gpIIb-IIIa, vitronectin receptor), proteins usually associated with focal contacts in tissue culture cells, are not concentrated at the ends of microfilaments in human platelets. It is suggested that the distribution of vinculin is due to competitive aggregation of vinculin close to the inner leaflet of the ventral plasma membrane and that sites of cytoskeleton-membrane linkage are important for generating supramolecular asymmetries of biological systems.

Caffeine and heat shock induce adenylate cyclase in Dictyostelium discoideum.

When vegetative cells of Dictyostelium discoideum were incubated in nutrient medium containing 5 mM caffeine, adenylate cyclase was induced and exceeded control values 30-fold after 6 h of incubation. The effect was dose-dependent and blocked by cycloheximide. Contact site A, a developmentally regulated membrane glycoprotein characteristic of aggregation-competent cells, was not induced by the treatment. The expression of a developmentally regulated gene coding for an unknown protein and hybridizing with the cDNA clone P26E8 was also stimulated, indicating that the regulation of expression occurs at the transcript level. Cells pretreated with caffeine in growth medium, washed and developed in starvation buffer showed an acceleration of development by 2 h as judged by stream formation and the appearance of contact sites A. The same effects were observed when cells were incubated under heat shock conditions (30 degrees C). The results indicate that caffeine stimulates the expression of devevelopmentally regulated early genes, and that their products, together with exogeneous factor(s), initiate subsequent steps of development.

Adenylate cyclase of Dictyostelium discoideum: solubilization and Mn2+-dependency.

Adenylate cyclase from Dictyostelium discoideum was solubilized under alkaline conditions using the zwitterionic detergent CHAPS. In contrast to the membrane bound adenylate cyclase, the solubilized enzyme can use only Mn2+, but is inactive in the presence of Mg2+.

Telemedicine in support of peacekeeping operations overseas: an audit.

BACKGROUND AND OBJECTIVE: Since 1993, the Department of Defense has augmented the medical support for Army units on peacekeeping operations in Macedonia through the medium of telemedicine. This project, known as Operation Primetime 1, was the first satellite-based telemedicine system deployed in support of remote primary-care physician in the U.S. military. Its declared aims are: (1) to improve the standard of care; (2) to reduce evacuations; (3) to support junior physicians in the field; and (4) to improve the military effectiveness of the deployed units. This paper audits the success in attaining those goals for the period January 1994 to April 1995. METHODS: A log was collated from the referring units and questionnaires completed by both referring and consulting physicians. The referring physicians were interviewed on their return from Macedonia, and a more detailed study was undertaken of cases in which a change in outcome was noted. Follow-up interview of consultants was not possible. RESULTS: A total of 53 consults were undertaken on 47 patients. The use of telemedicine affected the decision to evacuate 13 times (13/47), with a net reduction of 9 evacuations. Management of individual cases was changed in 30 of the 47 cases in which telemedicine was used. Physician confidence and military effectiveness were also improved. The level of utilization of the system was largely dependent on a training and sustainment program. Units and General Medical Officers who were trained in the clinical use of telemedicine and the technical sustainment of the equipment used the system; those who were not, did not. Most patients (45/47) were treated satisfactorily with a single consult. Telemedicine under these circumstances seems to be cost effective. The deployed sites chose the referral centers that provided the best service. CONCLUSIONS: Telemedicine is a valuable tool capable of augmenting medical support to deployed military units. A successful deployed telemedicine project requires an integrated support package that includes adequate provision for training and equipment sustainment at both ends of the link. Experience with telemedicine in Operation Primetime indicates the potential for substantial cost savings as well as cost-effective medical care. Further application of telemedicine should be encouraged. Successful deployment of telemedicine projects may hinge on an integrated support package.

Investigation of the role of calpain as a stimulus-response mediator in human platelets using new synthetic inhibitors.

A series of peptidyl diazomethanes and monofluoromethane with structures specific for calpain have been synthesized and tested for their ability to inhibit calpain activity in vivo, using human platelets as a model system. Calpain activity in vivo was determined by observing proteolysis of actin-binding protein and talin, two known substrates of calpain. Very potent inhibitors, which emerged from this study, were used to investigate the role of calpain in some platelet response processes. Our results show that calpain-mediated proteolysis in platelets is not an obligatory event leading to change of cell shape, adhesion to glass and spreading, aggregation and 5-hydroxytryptamine release. Two of the inhibitors were iodinated with 125I and used to radiolabel the enzyme in vivo. To our knowledge, this work also represents the first report describing the affinity labelling of calpain in human platelets using irreversible radioactive inhibitors.

Phosphorylation of vinculin in human platelets spreading on a solid surface.

Vinculin is a cytoskeletal protein believed to be involved in linking microfilaments to the cell membrane. It is a substrate for the Ca(2+)- and phospholipid-dependent protein kinase C. We show here that when human platelets attach and spread on a solid surface, the alpha isoforms of vinculin become phosphorylated at serine and/or threonine residues. Phosphorylation is dependent on adhesion to a surface, since suspended, unattached platelets can produce filopodia but no phosphorylation of vinculin. Phosphorylation is also dependent on actin polymerization, as it does not occur when platelets had been pretreated with cytochalasin B. Most likely, protein kinase C is responsible for the phosphorylation of vinculin, since phosphorylation also occurs when platelets are treated with a phorbol ester, which activates protein kinase C, and is blocked by treatment with a staurosporine derivative which inhibits this enzyme. These results suggest that phosphorylation plays a role in anchoring vinculin at sites of microfilament-membrane interaction.