Ocular retardation mouse caused by Chx10 homeobox null allele: impaired retinal progenitor proliferation and bipolar cell differentiation

Ocular retardation (or) is a murine eye mutation causing microphthalmia, a thin hypocellular retina and optic nerve aplasia. Here we show that mice carrying the OrJ allele have a premature stop codon in the homeobox of the Chx10 gene, a gene expressed at high levels in uncommitted retinal progenitor cells and mature bipolar cells. No CHX10 protein was detectable in the retinal neuroepithelium of orJ homozygotes. The loss of CHX10 leads both to reduced proliferation of retinal progenitors and to a specific absence of differentiated bipolar cells. Other major retinal cell types were present and correctly positioned in the mutant retina, although rod outer segments were short and retinal lamination was incomplete. These results indicate that Chx10 is an essential component in the network of genes required for the development of the mammalian eye, with profound effects on retinal progenitor proliferation and bipolar cell specification or differentiation. off

Circulating immune complexes in IgA nephropathy consist of IgA1 with galactose-deficient hinge region and antiglycan antibodies

Circulating immune complexes (CICs) isolated from sera of patients with IgA nephropathy (IgAN) consist of undergalactosylated, mostly polymeric, and J chain-containing IgA1 and IgG antibodies specific for N-acetylgalactosamine (GalNAc) residues in O-linked glycans of the hinge region of IgA1 heavy chains. Antibodies with such specificity occur in sera of IgAN patients, and in smaller quantities in patients with non-IgA proliferative glomerulonephritis and in healthy controls; they are present mainly in the IgG (predominantly IgG2 subclass), and less frequently in the IgA1 isotype. Their specificity for GalNAc was determined by reactivity with IgA1 myeloma proteins with enzymatically removed N-acetylneuraminic acid (NeuNAc) and galactose (Gal); removal of the O-linked glycans of IgA1 resulted in significantly decreased reactivity. Furthermore, IgA2 proteins that lack the hinge region with O-linked glycans but are otherwise structurally similar to IgA1 did not react with IgG or IgA1 antibodies. The re-formation of isolated and acid-dissociated CICs was inhibited more effectively by IgA1 lacking NeuNAc and Gal than by intact IgA1. Immobilized GalNAc and asialo-ovine submaxillary mucin (rich in O-linked glycans) were also effective inhibitors. Our results suggest that the deficiency of Gal in the hinge region of IgA1 molecules results in the generation of antigenic determinants containing GalNAc residues that are recognized by naturally occurring IgG and IgA1 antibodies.

Patients with IgA nephropathy have increased serum galactose-deficient IgA1 levels

Immunoglobulin A (IgA) nephropathy is the most prevalent form of glomerulonephritis worldwide. A renal biopsy is required for an accurate diagnosis, as no convenient biomarker is currently available. We developed a serological test based upon the observation that this nephropathy is characterized by undergalactosylated IgA1 in the circulation and in mesangial immune deposits. In the absence of galactose, the terminal saccharide of O-linked chains in the hinge region of IgA1 is terminal or sialylated N-acetylgalactosamine. A lectin from Helix aspersa, recognizing N-acetylgalactosamine, was used to develop an enzyme-linked immunosorbent assay that measures galactose-deficient IgA1 in serum. The median serum lectin-binding IgA1 level was significantly higher for 153 Caucasian adult patients with IgA nephropathy without progression to end-stage renal disease as compared with that for 150 healthy Caucasian adult controls. As the lectin-binding IgA1 levels for the controls were not normally distributed, the 90th percentile was used for determination of significant elevation. Using a value of 1076 U/ml as the upper limit of normal, 117 of the 153 patients with IgA nephropathy had an elevated serum lectin-binding IgA1 level. The sensitivity as a diagnostic test was 76.5%, with specificity 94%; the positive predictive value was 88.6% and the negative predictive value was 78.9%. We conclude that this lectin-binding assay may have potential as a noninvasive diagnostic test for IgA nephropathy.

Confocal imaging of glutathione redox potential in living plant cells

Reduction-oxidation-sensitive green fluorescent protein (roGFP1 and roGFP2) were expressed in different sub-cellular compartments of Arabidopsis and tobacco leaves to empirically determine their performance as ratiometric redox sensors for confocal imaging in planta. A lower redox-dependent change in fluorescence in combination with reduced excitation efficiency at 488 nm resulted in a significantly lower dynamic range of roGFP1 than for roGFP2. Nevertheless, when targeted to the cytosol and mitochondria of Arabidopsis leaves both roGFPs consistently indicated redox potentials of about -320 mV in the cytosol and -360 mV in the mitochondria after pH correction for the more alkaline matrix pH. Ratio measurements were consistent throughout the epidermal cell layer, but results might be attenuated deeper within the leaf tissue. Specific interaction of both roGFPs with glutaredoxin in vitro strongly suggests that in situ both variants preferentially act as sensors for the glutathione redox potential. roGFP2 targeted to plastids and peroxisomes in epidermal cells of tobacco leaves was slightly less reduced than in other plasmatic compartments, but still indicated a highly reduced glutathione pool. The only oxidizing compartment was the lumen of the endoplasmic reticulum, in which roGFP2 was almost completely oxidized. In all compartments tested, roGFP2 reversibly responded to perfusion with H(2)O(2) and DTT, further emphasizing that roGFP2 is a reliable probe for dynamic redox imaging in planta. Reliability of roGFP1 measurements might be obscured though in extended time courses as it was observed that intense irradiation of roGFP1 at 405 nm can lead to progressive photoisomerization and thus a redox-independent change of fluorescence excitation ratios.

Relaxin is essential for renal vasodilation during pregnancy in conscious rats

Marked vasodilation in the kidney and other nonreproductive organs is one of the earliest maternal adaptations to occur during pregnancy. Despite the recognition of this extraordinary physiology for over four decades, the gestational hormone responsible has remained elusive. Here we demonstrate a key role for relaxin, a member of the IGF family that is secreted by the corpus luteum in humans and rodents. Using a gravid rodent model, we employ two approaches to eliminate relaxin or its biological activity from the circulation: ovariectomy and administration of neutralizing antibodies. Both abrogate the gestational elevation in renal perfusion and glomerular filtration, as well as preventing the reduction in myogenic reactivity of isolated, small renal arteries. Osmoregulatory changes, another pregnancy adaptation, are also abolished. Our results indicate that relaxin mediates the renal vasodilatory responses to pregnancy and thus may be important for maternal and fetal health. They also raise the likelihood of a role for relaxin in other cardiovascular changes of pregnancy, and they suggest that, like estrogen, relaxin should be considered a regulator of cardiovascular function.

Inactivation of p53 gene in human and murine osteosarcoma cells

We examined structure and expression of the p53 and Rb genes in a C3HOS transplantable mouse model of osteosarcoma. The results were compared to analogous studies conducted with five human osteosarcoma cell lines. The p53 gene was found rearranged in the mouse tumour. The rearrangement mapped to the first intron region of the p53 gene and as a result, no p53 expression could be detected in C3HOS tumours. Using p53 genomic probes, we have detected the same rearrangement in the original radiation-induced tumour and the various clones that were isolated from it. Deletion and rearrangement of the p53 gene were also found in three out of five of the human osteosarcoma cell lines (MG-63, G-292, Saos-2). No p53 expression could be detected in these three cell lines. In the affected human osteosarcoma cell lines, the rearrangement involved the first intron region. In addition, the mouse tumor was analysed for structural and expression changes in the Rb and the c-myc genes. Normal expression of both genes were detected in the murine tumour. Only one (Saos-2) human osteosarcoma cell line exhibited gross structural alteration in the retinoblastoma gene. The results suggest that the inactivation of p53 may be an important step in the development of osteosarcomas, and that a rearrangement affecting the first intron is common in osteosarcomas.

Polylactide/polyglycolide antibiotic implants in the treatment of osteomyelitis. A canine model

Osteomyelitis with Staphylococcus aureus was established in the tibiae of twenty-six adult mongrel dogs. After confirmation of infection at four weeks, all animals had operative débridement and were then divided into three treatment groups. Group 1 (eight animals [sixteen tibiae]) was treated with parenteral administration of gentamicin (three milligrams per kilogram of body weight per day) every eight hours for four weeks. Group 2 (nine animals [nine tibiae]) was treated with a polymethylmethacrylate implant containing 100 milligrams of gentamicin that was placed in the tibia for six weeks. Group 3 (nine animals [nine tibiae]) was treated with a polylactide/polyglycolide implant containing 100 milligrams of gentamicin that was placed in the tibia for six weeks. All animals were killed at the end of treatment. At that time, specimens of tissue were obtained for quantitative culture as well as for antibiotic immunoassay. In the groups that had been treated with an implant, serum was obtained for the measurement of serum drug levels after débridement; after the implantation; four, seven, and twenty-one days postoperatively; and immediately before the animals were killed. The infection was eradicated in ten of the sixteen tibiae in Group 1, in eight of the nine tibiae in Group 2, and in all nine tibiae in Group 3.(ABSTRACT TRUNCATED AT 250 WORDS)

The decrease in number and change in phenotype of mucosal-associated invariant T cells in the elderly and differences in men and women of reproductive age

Mucosal-associated invariant T (MAIT) cells are innate-like T cells comprising up to 10% of the peripheral blood T cells in humans. During ontogeny, MAIT cells can first be detected in the cord blood in low amounts, but rise steadily after birth. In this population-based study, we show that their counts continue to increase, reaching maximal levels (4.5% of CD3(+) cells, 65 cells/μl) in the third and fourth decenniums. At this age, the amounts of MAIT cells exhibit the highest interindividual variability. The values then dramatically decline; subjects 80 years old and older have on average 10 times less MAIT cells, both absolutely and as a percentage among CD3(+) T cells, than subjects in fertile age. The senescence of MAIT cells is associated with decreased CD8/double negative (DN) ratio. Finally, we observed significantly higher amounts of MAIT cells in women of reproductive age than in men of the same age. Our data suggest that further studies aimed at elucidating a role of MAIT cells in human pathologies must recruit age- and gender-matched controls.

In vivo flow cytometer for real-time detection and quantification of circulating cells

An in vivo flow cytometer is developed that allows the real-time detection and quantification of circulating fluorescently labeled cells in live animals. A signal from a cell population of interest is recorded as the cells pass through a slit of light focused across a blood vessel. Confocal detection of the excited fluorescence allows continuous monitoring of labeled cells in the upper layers of scattering tissue, such as the skin. The device is used to characterize the in vivo kinetics of red and white blood cells circulating in the vasculatúre of the mouse ear. Potential applications in biology and medicine are discussed.

Progress in molecular and genetic studies of IgA nephropathy

Several new findings emerged recently from biochemical, genetic, and molecular studies of patients with IgA nephropathy. It appears that immunoglobulin A1-secreting cells of IgA nephropathy patients produce increased amounts of aberrantly glycosylated IgA1 in which the O-linked glycans in the hinge region are deficient in the content of galactose. The galactose-deficient IgA1 in the circulation is recognized by naturally occurring antibodies with anti-glycan specificity, and immune complexes are formed. These circulating immune complexes escape hepatic degradation and eventually are deposited in the kidney mesangium. Resident mesangial cells bind the IgA-containing immune complexes with the involvement of a novel IgA receptor and become activated. A familial form of IgA nephropathy has been linked to chromosome 6q22-23. Recent progress in molecular analyses of IgA nephropathy thus defines this disease as an autoimmune process with a novel IgA mesangial receptor and certain genetically determined traits.

CEA monitoring among patients in multi-institutional adjuvant G.I. therapy protocols

The Gastrointestinal Tumor Study Group (GITSG) has since 1975 included protocols for monitoring carcinoembryonic antigen (CEA) levels in its colorectal cancer adjuvant trials. Among the 563 patients on the colon cancer study (GI 6175) and the 207 patients on the rectal cancer study (GI 7175), one third had preoperative CEA determinations and more than 90% had some postoperative CEA monitoring. Colon cancer patients whose preoperative CEA was greater than 5 ng/ml had a greater probability of recurring than those whose values were lower (33% versus 18% recurrence with 21 months minimum follow-up; p < 0.05). The prognostic value of preoperative CEA was apparent only in patients with Dukes' C1 colon tumors. Preoperative CEA values were not of prognostic significance among the rectal adenocarcinoma patients. Although elevated levels of CEA after resection of either colon or rectum cancers were strongly associated with subsequent tumor recurrence, no single CEA value, arbitrarily defined as "elevated", provided an adequate screening test with both high sensitivity and high specificity. Postoperative CEA elevations were more strongly predictive of recurrence when part of a steadily rising trend. In the colon cancer study, the median monthly increase in CEA for disease-free patients was estimated to be zero, and for the relapsed patients 5.8%. The corresponding estimates for patients on the rectal cancer protocol were zero and 7.8%. Only 36 of the 344 disease-free patients on the colon protocol and 14 of the 94 disease-free patients on the rectal protocol (15%) exhibited a rate of increase of CEA as high as 3% per month over the entire period of observation. Two thirds of the relapsed patients on both studies showed a rate of increase this high or higher. The patterns of CEA rise in individual patients were quite varied, however, and monthly rates of increase as established in our study are not to be used as guidelines in patient management.

Periodontal response after tooth movement into intrabony defects

The present study was undertaken since conflicting evidence exists regarding the effect of such tooth movement on levels of connective tissue attachment. Localized intrabony pockets were produced around isolated incisors in four rhesus monkeys. The root surfaces were planned to the level of the bone at the base of the angular bony defects. An oral hygiene regime was begun and continued for the remainder of the study. The experimental teeth were moved orthodontically into, and through, the original area of the intrabony defect. Two months after cessation of active tooth movement, block specimens were removed for histologic analysis. Control specimens comprised those teeth with induced periodontal defects, but without tooth movement. In specimens not subjected to tooth movement, angular bony defects were present and epithelium lined the root surface to the apical extent of instrumentation. The alveolar bone adjacent to the orthodontically moved teeth no longer had angular defect morphology. On the pressure side, epithelium lined the root surface, was interposed between root surface and bone and terminated at the apical limit of root instrumentation. On the tension side, the crest of the bone was located apical to the level of root planing, and epithelium lined the instrumented portion of the root surface. It was concluded that orthodontic tooth movement into intrabony periodontal defects was without effect upon the levels of connective tissue attachment.

Endothelin-A receptor antagonism attenuates the hypertension and renal injury in Dahl salt-sensitive rats

The aim of this study was to examine the role of endothelin-A (ET(A)) receptors in mediating the hypertension and renal injury associated with high salt intake in Dahl salt-sensitive (DS) rats. To achieve this goal, we examined the effects of chronic selective ET(A) antagonist (A-127722) treatment at a dose of 10 mg/kg/d on arterial pressure, renal function, and morphology in DS and Dahl salt-resistant (DR) rats placed on a high sodium (8% NaCl) diet (HSD) for 3 weeks. Placement of DS rats (n=13) on HSD for 3 weeks caused a progressive increase in systolic pressure (from 118+/-3 to 186+/-15 mm Hg). The increase in systolic pressure was significantly attenuated (from 125+/-4 to 167+/-12 mm Hg) in DS rats treated with A-127722 (n=13). Mean arterial pressure (MAP) measured directly at the end of the study was also significantly lower by 18 mm Hg (P<.02) in the DS rats treated with A-127722. The slope of the chronic pressure-natriuresis curve was shifted to the right in DS rats and to the left by chronic ET(A) receptor blockade in DS rats. The hypertension in DS rats was associated with marked proteinuria (from 4.1+/-1.1 to 74.3+/-5.3 mg/24 h/100 g body weight) that was significantly attenuated (from 5.7+/-1.2 to 55.2+/-6.5 mg/24 h/100 g body weight) in DS rats treated with A-127722. The percentage of glomeruli displaying fibrosis, hypercellularity, and hyalinization was also significantly reduced after treatment with A-127722 in DS rats. Arterial pressure, protein excretion, renal hemodynamics, and morphologic structure were not significantly changed in response to ET(A) receptor blockade in DR rats placed on HSD. These data indicate that endothelin-A receptor activation may play a role in the exacerbation of hypertension and development of renal injury in DS rats.

Enhanced vascular reactivity during inhibition of nitric oxide synthesis in pregnant rats

Pregnancy-induced hypertension has been suggested to be mediated by several mechanisms, including reduced nitric oxide (NO) synthesis. In this study, the effects of chronic treatment with the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) on blood pressure and the underlying changes in vascular reactivity were investigated in virgin and late-pregnancy Sprague-Dawley rats. The systolic blood pressure was 120+/-2, 124+/-5, 116+/-4, and 171+/-5 mm Hg in untreated virgin, virgin treated with L-NAME, untreated pregnant, and pregnant treated with L-NAME rats, respectively. The rats were killed, and the thoracic aorta was cut into strips for measurement of active stress in response to alpha1-adrenergic stimulation with phenylephrine and membrane depolarization by high KCl. In pregnant rats, the maximal active stress to phenylephrine (0.31+/-0.03 x 10(4) N/m2) and the high-KCl-induced active stress (0.55+/-0.09 x 10(4) N/m2) were smaller than those in virgin rats. By contrast, in the L-NAME-treated pregnant rats, the maximal phenylephrine-induced active stress (0.76+/-0.1 x 10(4) N/m2) was greater than that in virgin rats (0.52+/-0.1 x 10(4) N/m2), whereas the high-KCl-induced active stress (1.08+/-0.14 x 10(4) N/m2) was indistinguishable from that in virgin rats (1.03+/-0.14 x 10(4) N/m2). Treatment with L-NAME did not affect the phenylephrine-releasable Ca2+ stores in pregnant rats and had minimal effect on active stress in virgin rats. Thus, reduction of NO synthesis during late pregnancy is associated with a significant increase in blood pressure and vascular responsiveness to alpha-adrenergic stimulation, which can possibly be explained in part by enhanced Ca2+ entry from extracellular space. However, other mechanisms such as increased myofilament force sensitivity to Ca2+ and/or activation of a completely Ca2+-independent mechanism cannot be excluded.

PAHdb: a locus-specific knowledgebase

PAHdb is an online relational locus-specific "mutation database" (http://www.mcgill.ca/pahdb) for the human phenylalanine hydroxylase gene (symbol PAH) and its associated phenotypes (protein, metabolic, clinical). When combined with associated information (population distribution of allele, haplotype association, etc.) PAHdb functions as a knowledgebase. From the outset, and in the absence of raw data (e.g., sequence gels), PAHdb has instead been an annotated repository of information about mutations maintained by a team of curators. It is also disease-oriented, being focused on a variant phenotype (hyperphenylalaninemia (HPA) and its most important form of disease, phenylketonuria (PKU)) resulting from primary dysfunction of the PAH enzyme (EC 1.14.16.1); it is "patient friendly" in that it contains information for those personally involved with HPA/PKU (MIM# 261600). PAHdb also serves its community through direct interaction.

Vsx1, a rapidly evolving paired-like homeobox gene expressed in cone bipolar cells

The paired-like homeodomain (HD) protein Chx10 is distinguished by the presence of the CVC domain, a conserved 56 amino acid sequence C-terminal to the HD. In mammals, Chx10 is essential both for the proliferation of retinal progenitor cells and for the formation or survival of retinal bipolar interneurons. We describe the cloning and characterization of a mouse Chx10 homologue, Vsx1; phylogenetic analysis suggests that Vsx1 and its putative vertebrate orthologues have evolved rapidly. Vsx1 expression in the adult is predominantly retinal. Whereas Chx10 is expressed both in retinal progenitors in the developing eye and apparently in all bipolar cells of the mature retina, Vsx1 expression is first detected in the eye at postnatal day 5, where it is restricted to cone bipolar cells.

Unravelling the multilayer growth of the fullerene C60 in real time

Molecular semiconductors are increasingly used in devices, but understanding of elementary nanoscopic processes in molecular film growth is in its infancy. Here we use real-time in situ specular and diffuse X-ray scattering in combination with kinetic Monte Carlo simulations to study C60 nucleation and multilayer growth. We determine a self-consistent set of energy parameters describing both intra- and interlayer diffusion processes in C60 growth. This approach yields an effective Ehrlich-Schwoebel barrier of EES=110 meV, diffusion barrier of ED=540 meV and binding energy of EB=130 meV. Analysing the particle-resolved dynamics, we find that the lateral diffusion is similar to colloids, but characterized by an atom-like Schwoebel barrier. Our results contribute to a fundamental understanding of molecular growth processes in a system, which forms an important intermediate case between atoms and colloids.

Differential expression of renal nitric oxide synthase isoforms during pregnancy in rats

Alterations in nitric oxide (NO) production have been suggested to play a role in mediating changes in renal function during normal pregnancy and in pregnancy-induced hypertension. Although NO production is enhanced during normal pregnancy, the mechanisms for the increase are unknown. The purpose of this study was to determine whether the elevation in NO production during pregnancy is associated with increases in renal expression of endothelial (eNOS), inducible (iNOS), and neuronal (nNOS) nitric oxide synthases. To achieve this goal we examined systemic and renal hemodynamics, urinary excretion of nitrate/nitrite, and renal protein expression of the three NOS isoforms in prepregnant rats, pregnant rats at days 6, 13, and 19 of gestation and at day 4 postpartum. Mean arterial pressure decreased by 14% in late pregnancy whereas the glomerular filtration rate and renal plasma flow increased by 21% and 24%, respectively, in mid pregnancy. Excretion of nitrate/nitrite increased throughout pregnancy with a 3.4-fold increase present at day 19 (12.2+/-0.7 to 41.1+/-1.3 micromol/24 h). Renal eNOS protein expression decreased by 39% during pregnancy with the lowest level resulting at day 19 and returning to virgin levels by day 4 post partum. In contrast, renal iNOS and nNOS protein expression increased 31% and 25%, respectively, with highest expression occurring for both at day 13 of pregnancy. These data suggest that the increased NO production and renal hemodynamics associated with pregnancy in rats may be caused by the upregulation of iNOS and nNOS in the kidney.

Chemical composition and antimicrobial activity of Cymbopogon citratus and Cymbopogon giganteus essential oils alone and in combination

As part of ongoing research on the chemical composition and the antimicrobial properties of Burkinabe plants essential oils alone and in combination, essential oils (EOs) from leaves of Cymbopogon citratus and Cymbopogon giganteus from Burkina Faso were analyzed by GC-FID and GC-MS. Five constituents, which accounted for 96.3% of the oil, were identified in the EO of C. citratus. Geranial (48.1%), neral (34.6%) and myrcene (11.0%) were the major constituents. For C. giganteus a total of eight compounds were identified which represented 86.0% of the oils extracted. The dominant compounds were limonene (42%) and a set of monoterpene alcohols: trans-p-mentha-1(7),8-dien-2-ol (14.2%), cis-p-mentha-1(7),8-dien-2-ol (12%), trans-p-mentha-2,8-dien-1-ol (5.6%) and cis-p-mentha-2,8-dien-1-ol (5.2%). The EOs were tested against nine bacteria by using disc diffusion and microdilution methods. C. giganteus EO showed antimicrobial effects against all microorganisms tested whereas C. citratus EO failed to inhibit Pseudomonas aeruginosa. The antimicrobial activity of combinations of the two EOs was quantified by the checkerboard method. Combinations of the two EOs exerted synergistic, additive and indifferent antimicrobial effects. Results of the present investigation provide evidence that the combinations of plant EOs could be assessed for synergistic activity in order to reduce their minimum effective dose.

Arbuscular mycorrhiza alter the concentration of essential oils in oregano (Origanum sp., Lamiaceae)

The effect of root colonization by Glomus mosseae on the qualitative and quantitative pattern of essential oils (EO) was determined in three oregano genotypes (Origanum sp.). To exclude a simple P-mediated effect through mycorrhization the effect of P application to plants on the EO accumulation was also tested. In two genotypes the leaf biomass was increased through mycorrhization. Root colonization by the arbuscular mycorrhizal fungus (AMF) did not have any significant effect on the EO composition in oregano; however, in two genotypes the EO concentration significantly increased. As EO levels in P-treated plants were not enhanced, we conclude that the EO increase observed in mycorrhizal oregano plants is not due to an improved P status in mycorrhizal plants, but depends directly on the AMF-oregano plant association.

Role of aberrant glycosylation of IgA1 molecules in the pathogenesis of IgA nephropathy

Studies of the properties of immune complexes (IC) in the circulation, urine, and mesangium of IgA nephropathy (IgAN) patients have provided data relevant to the pathogenesis of this disease. IC contain predominantly polymeric IgA1 molecules which are deficient in galactose (Gal) residues on O-linked glycan chains in the hinge region (HR) of their heavy (H) chains. As a result of this aberrancy, a novel antigenic determinant(s) involving N-acetylgalactosamine (GalNAc) and perhaps sialic acid (SA) of O-linked glycans is generated and recognized by naturally occurring GalNAc-specific antibodies. Thus, IC in IgAN consist of Gal-deficient IgA1 molecules as an antigen, and GalNAc-specific IgG and/or IgA1 as an antibody. IgG antibodies to Gal-deficient IgA1 are probably induced by cross-reactive microbial antigens; they are present at variable levels not only in humans with or without IgAN but also in many phylogenetically diverse vertebrate species. Incubation of human mesangial cells with IC from sera of IgAN patients indicated that stimulation of cellular proliferative activity was restricted to the large (>800 kDa) complexes. These findings suggest that experimental approaches that prevent the formation of large Gal-deficient IgA1-IgG IC may be applied ultimately in an immunologically mediated therapy.

Vascular actions of relaxin: nitric oxide and beyond

The peptide hormone relaxin regulates the essential maternal haemodynamic adaptations in early pregnancy through direct actions on the renal and systemic vasculature. These vascular actions of relaxin occur mainly through endothelium-derived NO-mediated vasodilator pathways and improvements in arterial compliance in small resistance-size arteries. This work catalysed a plethora of studies which revealed quite heterogeneous responses across the different regions of the vasculature, and also uncovered NO-independent mechanisms of relaxin action. In this review, we first describe the role of endogenous relaxin in maintaining normal vascular function, largely referring to work in pregnant and male relaxin-deficient animals. We then discuss the diversity of mechanisms mediating relaxin action in different vascular beds, including the involvement of prostanoids, VEGF, endothelium-derived hyperpolarisation and antioxidant activity in addition to the classic NO-mediated vasodilatory pathway. We conclude the review with current perspectives on the vascular remodelling capabilities of relaxin.

LINKED ARTICLES

This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.