G protein beta3 subunit 825T genotype is not associated with differing outcome in pediatric renal transplant recipients

Recent studies have identified a novel polymorphism (C825T) of the gene encoding the beta3 subunit of heterotrimeric G proteins (GNB3), associated with enhanced activation of G proteins, which appears to be more common in hypertensive patients. The donor GNB3 825TT genotype was associated with reduced kidney allograft survival in adults. We examined (in 100 Caucasian pediatric renal transplant recipients) whether the GNB3 (C825T) polymorphism was associated with disease progression and outcome after renal transplantation. The slope of 1/creatinine was determined by linear regression analysis of a median of 12 points before and after renal transplantation, and the population was divided into two groups of equal size, before and after transplantation, according to the slope. The observed frequencies were 57 for the CC, 33 for the CT, and 10 for the TT haplotype. For comparison, 738 consecutive newborn babies with the same ethnic background were typed in the same hospital. Allele frequencies were statistically not significantly different (chi-square test, p = 0.1327). When dividing the pediatric renal transplant recipients into two groups with regard to the slope of 1/creatinine, both before and after renal transplantation, the observed proportions were CC 26, CT 17, and TT 7 in the group with the poorer slope and CC 31, CT 16, and TT 3 in the group with the better slope before renal transplantation (not significant [NS], chi-square test, p = 0.1777). The observed proportions after renal transplantation were CC 26, CT 16, and TT 8 in the group with the poorer slope and CC 31, CT 15, and TT 4 in the group with the better slope, respectively (NS, chi-square test, p = 0.167). Allograft survival was not associated with the T allele. In conclusion, in a sizeable number of pediatric renal transplant recipients the GNB3 C825T polymorphism was found not to be a genetic risk factor for end-stage kidney disease. In addition, kidney graft function and survival was also found not to be associated with a recipient GNB3 C825T polymorphism.     

Vasculogenesis and angiogenesis in the early human placenta

Vasculogenesis and angiogenesis are two consecutive processes during blood vessel development in the human placenta. While vasculogenesis, which is the formation of first blood vessels, is achieved by differentiation of pluripotent mesenchymal cells into haemangiogenic stem cells. The subsequent step, angiogenesis, is characterized by development of new vessels from already existing vessels. In this review, we aim to give an overview of vasculogenesis and angiogenesis during the first trimester of human placental development. Recent studies have shown that at the very early stages of placental development, cytotrophoblasts trigger vasculogenesis and angiogenesis, whereas as pregnancy progresses Hofbauer and stromal cells take over the task of triggering blood vessel development. Important growth factors in this scenario are the vascular endothelial growth factor (VEGF) family and their receptors, as well as Tie-1 and Tie-2. This review depicts the molecular and morphological steps of vasculogenesis and angiogenesis, which can give further insights into human placental development and maturation disorders.     

Diminished neo-antigen response to keyhole limpet hemocyanin (KLH) vaccines in patients after treatment with chemotherapy or hematopoietic cell transplantation

Relapse is the most common cause of treatment failure for advanced cancer, even those treated with autologous hematopoietic cell transplantation (HCT). Effective tumor-specific immunotherapy may decrease relapse, however, this will fail if the immune system is unable to respond. We developed a strategy to test immune responses with a single injection of the bona fide neo-antigen KLH. The model was first tested in 37 normal volunteers using three KLH vaccines: Intracel KLH, Biosyn KLH, and Biosyn KLH + adjuvant. Despite finding the immunogenic epitope conserved in both products, intact Intracel KLH induced a better response compared to a purified 350/390 kDA subunit of KLH contained in the Biosyn KLH product. Addition of a synthetic oil adjuvant (Montanide ISA51) restored the response to a single injection of Biosyn KLH. A quantitative readout measured by a KLH-specific cellular and humoral response with isotype switching 1 month after KLH vaccination was established. To test the integrity of the adaptive immune response in cancer patients, we vaccinated 14 patients post-HCT and 19 patients with advanced cancer with KLH vaccines that elicited a 100% response rate in normal volunteers. In marked contrast to normal subjects, both responses were significantly impaired up to 16 months after autologous HCT with an intermediate response in advanced cancer patients. KLH vaccines are safe and require only a single injection to test neo-antigen responses providing an optimal platform for definitive testing of strategies to improve diminished immune recovery after chemotherapy or post-HCT.     

Effects of psychotherapy on hippocampal volume in out-patients with post-traumatic stress disorder: a MRI investigation

BACKGROUND: Magnetic resonance imaging (MRI) studies have especially reported smaller hippocampal volume in patients with post-traumatic stress disorder (PTSD), most of them war or sexual abuse victims. The present study compares the hippocampal volumes of out-patients with PTSD who had low co-morbidity rates to those of trauma-exposed control subjects without PTSD, and measures hippocampal volume changes in these patients after brief eclectic psychotherapy. We hypothesized that smaller hippocampal volumes are specific to PTSD and that hippocampal volume changes after effective psychotherapy would be measurable. METHOD: Eighteen patients with PTSD and 14 traumatized control subjects were examined with MRI. In a randomized clinical trial, the PTSD patients were assigned to treatment (n = 9) or waiting-list group (n = 9). After the former received psychotherapy for 4 months, the MRI was repeated on both PTSD groups. Three temporal lobe structures were manually segmented: hippocampus, amygdala, and parahippocampal gyrus. Volumetric analysis was used to measure grey matter, white matter, and cerebrospinal fluid. RESULTS: PTSD patients had significantly smaller hippocampal volumes at baseline (total 13.8%, right 13.5%, left 14.1%) compared to the control subjects. After effective psychotherapy, however, no volume changes were found in the smaller hippocampi. CONCLUSIONS: We confirmed previous findings of smaller hippocampal volume in PTSD in a new population made up of out-patients who experienced different types of traumas, reducing co-morbidity to a minimum. Smaller hippocampal volumes did not change after effective psychotherapy, even while symptoms resolved.     

Comparison of pleural pressure and transcutaneous diaphragmatic electromyogram in obstructive sleep apnea syndrome

STUDY OBJECTIVES: Based on studies of the impact of esophageal pressure on cardiovascular variables during sleep, this signal can be used to refine the severity level in the clinical diagnosis of obstructive sleep apnea syndrome. We hypothesized that relative changes in diaphragmatic electromyogram (EMG) can reflect short-term changes in esophageal pressure durng obstructive apneas and hypopneas. DESIGN: Diaphragmatic EMG was sampled at 0.25 kHz; diaphragmatic EMG waveform was band-pass filtered and digitally converted; the electrocardiogram artifact was eliminated; using a gating procedure, the waveform was fast-Fourier transformed and digitally rectified; and a moving average of 200 milliseconds was calculated. For each inspiratory effort during apnea or hypopnea, we calculated maximum diaphragmatic EMG and esophageal pressure. Data were normalized calculating the percentage difference between the first obstructed and each subsequent inspiratory effort during the respiratory event. SETTING: Sleep disorders laboratory. PATIENTS: 9 patients with moderate obstructive sleep apnea syndrome presenting with apneas and hypopneas during sleep. INTERVENTION: None. MEASUREMENTS AND RESULTS: 861 respiratory events were scored, and the evolution between esophageal pressure and diaphragmatic EMG were compared. Normalized data showed a good correlation between the 2 measures during apneas and hypopneas. There was a significant difference between the percentage increase in esophageal pressure and diaphragmatic EMG for apneas and hypopneas (esophageal pressure, apnea: 118.1% +/- 118.5%, hypopnea: 76.1% +/- 74.3%, P = .000; diaphragmatic EMG, 123.5% +/- 131.7%, hypopnea: 73.3% +/- 74.2%, P = .000). No significant differences for apnea or hypopnea were noted between the 2 measures under investigation. CONCLUSION: Diaphragmatic EMG may be clinically useful to describe relative changes in respiratory effort under conditions of apnea and hypopnea during sleep and to reliably dissociate central from obstructive events where esophageal pressure monitoring is not readily available.     

Molecular genetics of pseudoxanthoma elasticum: type and frequency of mutations in ABCC6

Pseudoxanthoma elasticum (PXE) is a systemic heritable disorder that affects the elastic tissue in the skin, eye, and cardiovascular system. Mutations in the ABCC6 gene cause PXE. We performed a mutation screen in ABCC6 using haplotype analysis in conjunction with direct sequencing to achieve a mutation detection rate of 97%. This screen consisted of 170 PXE chromosomes in 81 families, and detected 59 distinct mutations (32 missense, eight nonsense, and six likely splice-site point mutations; one small insertion; and seven small and five large deletions). Forty-three of these mutations are novel variants, which increases the total number of PXE mutations to 121. While most mutations are rare, three nonsense mutations, a splice donor site mutation, and the large deletion comprising exons 23-29 (c.2996_4208del) were identified as relatively frequent PXE mutations at 26%, 5%, 3.5%, 3%, and 11%, respectively. Chromosomal haplotyping with two proximal and two distal polymorphic markers flanking ABCC6 demonstrated that most chromosomes that carry these relatively frequent PXE mutations have related haplotypes specific for these mutations, which suggests that these chromosomes originate from single founder mutations. The types of mutations found support loss-of-function as the molecular mechanism for the PXE phenotype. In 76 of the 81 families, the affected individuals were either homozygous for the same mutation or compound heterozygous for two mutations. In the remaining five families with one uncovered mutation, affected showed allelic compound heterozygosity for the cosegregating PXE haplotype. This demonstrates pseudo-dominance as the relevant inheritance mechanism, since disease transmission to the next generation always requires one mutant allelic variant from each parent. In contrast to other previous clinical and molecular claims, our results show evidence only for recessive PXE. This has profound consequences for the genetic counseling of families with PXE.     

Properties of engineered vascular constructs made from collagen, fibrin, and collagen-fibrin mixtures

Vascular constructs were formed by embedding rat aortic smooth muscle cells in three-dimensional matrices of Type I collagen, fibrin, or a mixture of collagen and fibrin in a 1:1 ratio, at total matrix protein concentrations of 2 and 4 mg/ml. Morphological and mechanical properties were evaluated after 6 days in culture, and the effect of cyclic mechanical strain on collagen-fibrin mixture constructs was also studied. Constructs made with the lower protein concentration compacted to the greatest degree, and fibrin was found to enhance gel compaction. Each matrix type exhibited a characteristic stress-strain profile. Pure collagen had the highest linear modulus and pure fibrin had the lowest. The ultimate tensile stress was strongly dependent on the degree of gel compaction, and collagen-fibrin mixtures at 2mg/ml total protein content exhibited the highest values. Application of cyclic mechanical strain to collagen-fibrin mixture constructs caused a significant increase in gel compaction and a decrease in cell proliferation. The linear modulus, ultimate tensile stress and toughness of the constructs were all augmented by mechanical strain. These results demonstrate that the properties of engineered vascular tissues can be modulated by the combination of selected extracellular matrix components, and the application of mechanical stimulation.     

Tonic signaling from O₂ sensors sets neural circuit activity and behavioral state

Tonic receptors convey stimulus duration and intensity and are implicated in homeostatic control. However, how tonic homeostatic signals are generated and how they reconfigure neural circuits and modify animal behavior is poorly understood. Here we show that Caenorhabditis elegans O(2)-sensing neurons are tonic receptors that continuously signal ambient [O(2)] to set the animal's behavioral state. Sustained signaling relied on a Ca(2+) relay involving L-type voltage-gated Ca(2+) channels, the ryanodine and the inositol-1,4,5-trisphosphate receptors. Tonic activity evoked continuous neuropeptide release, which helps elicit the enduring behavioral state associated with high [O(2)]. Sustained O(2) receptor signaling was propagated to downstream neural circuits, including the hub interneuron RMG. O(2) receptors evoked similar locomotory states at particular O(2) concentrations, regardless of previous d[O(2)]/dt. However, a phasic component of the URX receptors' response to high d[O(2)]/dt, as well as tonic-to-phasic transformations in downstream interneurons, enabled transient reorientation movements shaped by d[O(2)]/dt. Our results highlight how tonic homeostatic signals can generate both transient and enduring behavioral change.     

A Variety of Opportunities for Immune Interactions During Trophoblast Development and Invasion

During human implantation and placentation, the direct cell to cell contact of fetal and maternal tissues gives room for a variety of immune interactions. Especially, the invasion of a subset of fetal trophoblast cells, called extravillous trophoblast, generate a very close interplay between the two individuals, enabling the attachment of the placenta to the uterine wall and the transformation of maternal spiral arteries to facilitate adequate nutrition of the fetus. During pregnancy, maternal and fetal factors closely interact to maintain pregnancy and smooth the process of delivery. At each and every stage and site, immunological interactions take place, including attachment of the blastocyst, development and invasion of trophoblast, and flow of maternal plasma and blood through the intervillous space of the placenta. Control mechanisms tightly regulate these interactions helping to evade fetal rejection by the mother. In this review, we highlight the morphological sites of development and feto‐maternal interaction to help immunological interested scientists and clinicians to develop hypotheses on the feto‐maternal immunological network during pregnancy.