Flow-induced [Ca2+]i increase depends on nucleotide release and subsequent purinergic signaling in the intact nephron

Flow induces cytosolic Ca(2+) increases ([Ca(2+)](i)) in intact renal tubules, but the mechanism is elusive. Mechanical stimulation in general is known to promote release of nucleotides (ATP/UTP) and trigger auto- and paracrine activation of P2 receptors in renal epithelia. It was hypothesized that the flow-induced [Ca(2+)](i) response in the renal tubule involves mechanically stimulated nucleotide release. This study investigated (1) the expression of P2 receptors in mouse medullary thick ascending limb (mTAL) using P2Y(2) receptor knockout (KO) mice, (2) whether flow increases induce [Ca(2+)](i) elevations in mTAL, and (3) whether this flow response is affected in mice that are deplete of the main purinergic receptor. [Ca(2+)](i) was imaged in perfused mTAL with fura-2 or fluo-4. It is shown that luminal and basolateral P2Y(2) receptors are the main purinergic receptor in this segment. Moreover, the data suggest presence of basolateral P2X receptors. Increases of tubular flow were imposed by promptly rising the inflow pressure, which triggered a marked increase of [Ca(2+)](i). This [Ca(2+)](i) response was significantly reduced in P2Y(2) receptor KO tubules (fura-2 ratio increase WT 0.44 +/- 0.09 [n = 28] versus KO 0.16 +/- 0.04 [n = 13]). Furthermore, the flow response was greatly inhibited with luminal and basolateral scavenging of extracellular ATP (apyrase 7.5 U/ml) or blockage of P2 receptors (suramin 300 microM). The flow response could still be elicited in the absence of extracellular Ca(2+). These results strongly suggest that increase of tubular flow elevates [Ca(2+)](i) in intact renal epithelia. This flow response is caused by release of bilateral nucleotides and subsequent activation of P2 receptors.     

Kinetics of the soluble IL-1 receptor type I during treatment with an LCAP filter in patients with inflammatory bowel disease

Leukocyte apheresis primarily used for treatment of inflammatory diseases such as inflammatory bowel disease (IBD). Beside an effect of the apheresis column, the plastic lines in the apheresis system might also have an effect due to interaction between the plastic surfaces and circulating leukocytes and plasma proteins. We recently reported generation of LL-37 in the plastic lines during leukocyte adsorbing apheresis. This generation might have a positive impact on the immunologic tolerance and therefore be one operational mechanism by which the apheresis treatment executes its effect. In the present study, we report a significant generation of sIL-1RI in the apheresis lines that is initially absorbed by the LCAP device. This finding, together with our previous data on IL-1Ra indicate that important members of the IL-1 family are significantly altered during the LCAP treatment of patients with IBD. Since IL-1 and its antagonists are important for regulation of inflammatory processes in IBD, we speculate that the LCAP related changes in sIL-1RI and IL-1Ra might impact the clinical outcome. These findings have to be taken into consideration when designing new apheresis techniques as well as sham-controlled studies.     

Expression of the rubber-like protein, resilin, in developing and functional insect cuticle determined using a Drosophila anti-Rec 1 resilin antibody

Background: The natural elastomeric protein, insect resilin, is the most efficient elastic material known, used to store energy for jumping and flight in a variety of insects. Here, an antibody to recombinant Drosophila melanogaster pro‐resilin is used to examine resilin expression in Drosophila and a wider range of insects. Results: Immunostaining of Drosophila embryos reveals anti‐resilin reactivity in epidermal patches that exhibit a dynamic spatial and temporal expression through late embryogenesis. Resilin is also detected in stretch receptors in the embryo. In developing adult Drosophila, resilin pads are described at the base of wings and at the base of flexible sensory hairs in pupae. Resilin is also detected in embryos of the tephritid fruitfly, Bactrocera tryoni, and two well‐known concentrations of insect resilin: the flight muscle tendon of the dragonfly and the pleural arch of the flea. Conclusions: The anti‐Rec1 antibody antibody developed using Drosophila pro‐resilin as antigen is cross‐reactive and is useful for detection of resilin in diverse insects. For the first time, resilin expression has been detected during embryogenesis, revealing segmental patches of resilin in the developing epidermis of Drosophila. Developmental Dynamics 241:333–339, 2012. © 2012 Wiley Periodicals, Inc.     

Female reproductive and hormonal factors and lung cancer mortality among never-smokers: A prospective cohort study of 287 408 Chinese women

There is growing, but inconsistent evidence suggesting oestrogen may play a key role in lung cancer development, especially among never-smoking women for whom lung cancer risk factors remain largely elusive. Using the China Kadoorie Biobank, a large-scale prospective cohort with 302 510 women aged 30 to 79 years recruited from 10 regions in China during 2004 to 2008, we assessed the risk of lung cancer death among self-reported never-smoking women who were cancer-free at baseline, in relation to age at menarche, age at menopause, time since menopause, prior use of oral contraceptives (OCP), number of livebirths, breastfeeding and age at first livebirth. Women were followed up to December 31, 2016 with linkage to mortality data. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox regression, adjusting for key confounders including several socio-demographic, environmental and lifestyle factors. Among 287 408 never-smoking women, 814 died from lung cancer with a median follow-up of 10.3 years. Women who had used OCP within 15 years prior to baseline had a significantly higher hazard of lung cancer death compared with never-users: HR = 1.85 (95% CI: 1.14-3.00) and risk increased by 6% with each additional year of use: HR = 1.06 (1.01-1.10). Among parous women, the hazard of lung cancer death increased by 13% with each single livebirth: HR = 1.13 (1.05-1.23); and among post-menopausal women, the risk increased by 2% with each year since menopause: HR = 1.02 (1.01-1.04). These results suggest that reproductive factors which were proxies for lower endogenous oestrogen level, for example, longer duration of OCP use, could play a role in lung cancer development.     

Trajectories of re-engagement: factors and mechanisms enabling patient return to HIV care in Zambia

Introduction

While disengagement from HIV care threatens the health of persons living with HIV (PLWH) and incidence-reduction targets, re-engagement is a critical step towards positive outcomes. Studies that establish a deeper understanding of successful return to clinical care among previously disengaged PLWH and the factors supporting re-engagement are essential to facilitate long-term care continuity.

Methods

We conducted narrative, patient-centred, in-depth interviews between January and June 2019 with 20 PLWH in Lusaka, Zambia, who had disengaged and then re-engaged in HIV care, identified through electronic medical records (EMRs). We applied narrative analysis techniques, and deductive and inductive thematic analysis to identify engagement patterns and enablers of return.

Results

We inductively identified five trajectories of care engagement, suggesting patterns in patient characteristics, experienced barriers and return facilitators that may aid intervention targeting including: (1) intermittent engagement;(2) mostly engaged; (3) delayed linkage after testing; (4) needs time to initiate antiretroviral therapy (ART); and (5) re-engagement with ART initiation. Patient-identified periods of disengagement from care did not always align with care gaps indicated in the EMR. Key, interactive re-engagement facilitators experienced by participants, with varied importance across trajectories, included a desire for physical wellness and social support manifested through verbal encouragement, facility outreach or personal facility connections and family instrumental support. The mechanisms through which facilitators led to return were: (1) the promising of living out one's life priorities; (2) feeling valued; (3) fostering interpersonal accountability; (4) re-entry navigation support; (5) facilitated care and treatment access; and (6) management of significant barriers, such as depression.

Conclusions

While preliminary, the identified trajectories may guide interventions to support re-engagement, such as offering flexible ART access to patients with intermittent engagement patterns instead of stable patients only. Further, for re-engagement interventions to achieve impact, they must activate mechanisms underlying re-engagement behaviours. For example, facility outreach that reminds a patient to return to care but does not affirm a patient's value or navigate re-entry is unlikely to be effective. The demonstrated importance of positive health facility connections reinforces a growing call for patient-centred care. Additionally, interventions should consider the important role communities play in fostering treatment motivation and overcoming practical barriers.     

Allergen challenge alters intracellular cytokine expression

The pathophysiology of asthma is complex and engages cascades of events in the cytokine network. We, therefore, investigated the impact of bronchial allergen challenge in humans on the cytokine profile of circulating lymphocytes. Peripheral blood samples from 10 patients with allergic asthma were collected before and 24 h after allergen provocation. Patients who mounted a late-phase reaction were designated dual responders opposite to single responders. Whole blood cells were stimulated by mitogen and intracellular interleukin (IL)-4 and interferon (IFN)-gamma were detected by flow cytometry. The allergen challenge induced a decrease in IL-4+CD4+ cells in the patients (P = 0.05), and a significant decrease (P < 0.05) in IFN-gamma+CD4+ cells was noted in single, but not dual, responders. In addition, there was a significant difference (P < 0.01) with respect to the changes in the IFN-gamma+CD4+ cells comparing dual and single responders. No corresponding changes were observed in CD8+ cells. The data suggest a possible on-going traffic of IFN-gamma and IL-4+CD4+ lymphocytes into the bronchial mucosa in relation to an allergen challenge and generate the hypothesis that a difference exists between single and dual responders in this respect. Because the CD4+IFN-gamma-producing cells have the capacity to downregulate the T-helper type 2 response, a reduced capacity in this aspect might contribute to the pathophysiology in dual responders.     

Role for mucosal immune responses and cell-mediated immune functions in protection from airborne challenge with Venezuelan equine encephalitis virus

Venezuelan equine encephalitis virus (VEEV) replicates in lymphoid tissues following peripheral inoculation and a high titre viraemia develops. Encephalitis develops after the virus enters the central nervous system from the blood, with the earliest neuronal involvement being via the olfactory nerve. Following aerosol challenge with virulent VEEV, the virus is thought to replicate in the nasal mucosa and there could be direct entry into the olfactory nerve via infected neuroepithelial cells. Protection from VEEV infection is believed to be primarily mediated by virus specific antibody. The correlation between protection and neutralising serum antibody titres is, however, inconsistent when the virulent virus is administered by the airborne route. This study demonstrates a link between antibody in serum and the nasal mucosa and protection by means of passive immunisation studies. Intra-nasal administration of antibody increased protection against airborne virus in Balb/c mice. Vaccination of mu MT strain mice that do not have functional B cells and cannot produce antibody revealed normal proliferation of spleen cells in vitro and robust cytokine production. Aerosol challenge of mu MT mice demonstrated that complete protection was only achieved when passive immunisation with antibody was supplemented with active immunisation with the TC-83 vaccine strain of the virus. This implies that cell-mediated immune functions are required for protection against airborne challenge with virulent VEEV.     

Detection of mRNA for ribosomal phosphoprotein P2 in normal colon and colonic tumours by in situ hybridization

We have localized the mRNA for the ribosomal phosphoprotein P2, a putative metastasis-related sequence, in normal colon and colonic carcinomas by in situ hybridization, using an oligonucleotide probe end-labelled with digoxigenin. The mRNA was identified in normal colonic epithelial cells, the intensity of the signal being greater in cells at the base of the crypts compared with those on the surface. A strong positive signal was also seen in plasma cells, in fibroblasts in granulation tissue, in ganglion cells, and in hepatocytes. A positive signal was identified in all 16 primary colonic tumours studied and in 7 hepatic metastases. In contrast to previous studies based on Northern blot analysis, we were unable to demonstrate increased expression in metastases as compared with primary tumours, nor could we demonstrate any increased expression in primary tumours which were associated with distant metastases.