Development of nitric oxide neurons in the chick embryo retina

Nitric oxide (NO) is a gas involved in neurotransmission in the central nervous system (CNS) and in vertebrate retinas. This paper describes five types of nitrergic neurons in developing and adult chick retina using the nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) reaction. Three of them, nitrergic types 1, 2 and 3, were observed in the inner nuclear layer, while nitrergic type 4 was observed in the ganglion cell layer; nitrergic type 5 were the retinal photoreceptors. Cell processes formed four nitrergic networks, which could be observed in the inner plexiform layer (IPL), at sublayers 1, 3a, 3b and 4. Another nitrergic network was observed in the outer plexiform layer (OPL). From hatching, the dendritic branches were completely developed in the IPL and in the OPL, forming the mentioned networks. Current evidence suggests that NO is coexpressed with other neurotransmitters in neurons of the CNS. Double-staining procedures, using NADPHd and 5HT immunohistochemistry in chicken retina, in a sequential or in an alternative manner, did not reveal the coexistence of these two neurotransmitters in the same neurons, but their networks matched in sublayers 1 and 4 of the IPL.     

Prognostic impact of the preoperatory neutrophil/lymphocyte index on early surgical complications of patients with colorectal cancer

Colorectal cancer (CRC) is found among those with greatest frequency and exponential increase worldwide, with high mortality rates, which are observed as increasing due to the postsurgical complications that come to present. Systemic inflammation participates in the development and progression of cancer; therefore, inflammatory and/or immunological response markers such as the neutrophil/lymphocyte index (NLI) can aid us in predicting the poor results of our interventions. The purpose of our study was to determine the impact of an NLI of ≥2.6 as a predictor of early postsurgical complications. By means of a prospective cohort, we analyzed 158 patients with CRC who were submitted to elective surgery with a later 30-day follow-up. We found that the preoperatory NLI of ≥2.6 obtained an odds ratio (OR) = 2.24 (95% confidence interval [CI], 1.15-4.36) as a prognostic factor of early postsurgical complications according to the Clavien-Dindo classification scale, which represents a low prognostic impact due to its predictive yield with low accuracy, which is the opposite of what other reports have previously published. The use of chemotherapy before the surgical procedure was also determined to be a risk factor for post-surgical complications.     

Systemic oxidative stress in children with cystic fibrosis with bacterial infection including Pseudomonas Aeruginosa

IntroductionOxidative stress (OS) occurs in cystic fibrosis (CF).ObjectiveThe objective of this work is to evaluate the influence of bacterial infection on biomarkers of OS (catalase [CAT], glutathione peroxidade [GPx], reduced glutathione [GSH]), markers of oxidative damage (protein carbonyls [PC], thiobarbituric acid reactive substances [TBARS]), together with the nutritional status and lung function in children with CF.MethodsCross‐sectional study including CF group (CFG, n = 55) and control group (CG, n = 31), median age: 3.89 and 4.62 years, respectively. CFG was distributed into CFG negative bacteriology (CFGB−, n = 27) or CFG positive bacteriology (CFGB+, n = 28), and CFG negative Pseudomonas aeruginosa (CFGPa−, n = 36) or CFG positive Pseudomonas aeruginosa (CFGPa+, n = 19).ResultsCompared with CG, CFG (P = .034) and CFGB+ (P = .042) had lower body mass index‐for‐age z‐score; forced expiratory volume in the first second was lower in CFGB+ and CFGPa+ (both P < .001). After adjusting for confounders and compared with CG: CFG showed higher TBARS (P ≤ .001) and PC (P = .048), and lower CAT (P = .004) and GPx (P = .003); the increase in PC levels was observed in CFGB+ (P = .011) and CFGPa+ (P = .001) but not in CFGB− (P = .510) and CFGPa− (P = .460).ConclusionsThese results indicate a systemic OS in children with CF. The presence of bacterial infection particularly Pseudomonas aeruginosa seems to be determinant to exacerbate the oxidative damage to proteins, in which PC may be a useful biomarker of OS in CF.     

Linfadenitis por micobacterias no tuberculosas: experiencia de 15 años

Objective

To study the epidemiology, clinical features, diagnosis, therapeutic management, and outcome of non-tuberculous mycobacterial lymphadenitis in a paediatric population of Aragón (Spain).

Assessment of ovarian vascularization in the polycystic ovary by three-dimensional power Doppler ultrasonography

Objective. To assess whether there are differences in ovarian echogenicity and vascularization as assessed by three-dimensional power Doppler angiography (3D-PDA) between women with polycystic ovaries (PCO) and women with normal ovaries (NO).

Methods. Eighty-three women were classified into two groups according to the 2003 Rotterdam consensus criteria. The NO group comprised women (n = 45) with regular menstrual cycles and proven fertility, whereas the PCO group comprised women (n = 38) with oligo-anovulation, clinical and/or biochemical features of hyperandrogenism, and polycystic ovary morphology at two-dimensional ultrasound. All women were evaluated by means of 3D-PDA. The parameters studied in both groups were follicle number per ovary (FNPO), ovarian volume (OV), mean gray value (MG) and three vascular indices: vascularization index (VI), flow index (FI) and vascularization flow index (VFI).

Results. The PCO group showed a higher mean OV as well as FNPO. No differences in MG, VI, FI and VFI were found between the groups.

Conclusions. 3D-PDA indices are not useful for discriminating between normal and polycystic ovaries.     

【In Press】Clinical outcomes of patterned laser trabeculoplasty as adjuvant therapy in open-angle glaucoma and ocular hypertension

AIM: To assess the efficacy and safety of patterned laser trabeculoplasty (PLT) as an adjunctive treatment in open-angle glaucoma (OAG) or ocular hypertension (OHT) patients who were under antiglaucoma medical treatment. METHODS: This study was a retrospective review of primary or secondary OAG patients and OHT patients with medically uncontrolled (≥18 mm Hg) intraocular pressure (IOP) who underwent 360º PLT from June 2016 to August 2016. Follow-up visits at week 1, and 1, 3 and 6mo were performed. IOP, best corrected visual acuity (BCVA), complications and eye drop glaucoma medication were recorded at each follow-up visit. Success was defined as IOP reduction ≥20% from baseline. RESULTS: Forty one eyes of 25 patients were included in this study. Pre-treatment mean IOP was 20.2±1.6 mm Hg. After PLT, IOP was 19.3±5.2, 16.1±2.7, 17.1±3.7 and 16.3±3.5 mm Hg, at 1wk, 1, 3 and 6mo, respectively. IOP reduction from baseline was statistically significant from the first month, remaining stable at 6mo (P<0.001). PLT success at 6mo of follow-up was 48.7%. The number of glaucoma medication per eye (P=0.10) and the mean BCVA both remained constant (P=0.37). Complications included transient IOP spikes in 4 eyes (9.7%) and peripheral anterior synechiae in 7 eyes (17.1%). CONCLUSION: PLT is an effective and safe method for the management of patients with OHT or OAG as an adjunctive therapy. Additional larger studies should be designed to verify the long-term stability of IOP reduction with this laser technology.     

Phase I/II study of gefitinib and capecitabine in patients with colorectal cancer

Objective The objectives of this phase I/II study were to determine the maximum tolerated dose (MTD), characterise the principal toxicities in the phase I part and assess the efficacy in the phase II part of gefitinib, an oral selective inhibitor of the epidermal growth factor receptor, in combination with capecitabine in patients with advanced colorectal cancer (CRC). Methods and patients Patients with advanced CRC were treated with gefitinib administered daily for 21 days and capecitabine administered twice daily for 14 days of a 21-day cycle. The dose levels of gefitinib (mg) and capecitabine (mg/m² bid) assessed were 250/1000 and 250/ 1250. An expanded cohort was enrolled at the MTD to better characterise toxicity and efficacy. A total of 32 previously treated patients were accrued. In the phase I part 10 subjects were treated, with one dose-limiting toxicity. Overall 26 patients were treated at the MTD of the combination, which was gefitinib 250 mg/day and capecitabine 1250 mg/m² twice daily. Results The most frequent treatment-related adverse events included asthenia, diarrhoea, nausea, rash and anorexia. The incidence profile was very similar in phases I and II. No objective responses were documented but 53% of the patients achieved stable disease as best response to therapy. Conclusions Capecitabine 1250 mg/m² twice daily 14 of 21 days and gefitinib at 250 mg/day can be safely administered in combination. The combination is relatively well tolerated. There were no objective responses, although an interesting stabilisation rate was documented, in previously treated advanced CRC patients.     

Mechanism of voltage sensing in Ca2+- and voltage-activated K+ (BK) channels

In neurosecretion, allosteric communication between voltage sensors and Ca²⁺ binding in BK channels is crucially involved in damping excitatory stimuli. Nevertheless, the voltage-sensing mechanism of BK channels is still under debate. Here, based on gating current measurements, we demonstrate that two arginines in the transmembrane segment S4 (R210 and R213) function as the BK gating charges. Significantly, the energy landscape of the gating particles is electrostatically tuned by a network of salt bridges contained in the voltage sensor domain (VSD). Molecular dynamics simulations and proton transport experiments in the hyperpolarization-activated R210H mutant suggest that the electric field drops off within a narrow septum whose boundaries are defined by the gating charges. Unlike Kv channels, the charge movement in BK appears to be limited to a small displacement of the guanidinium moieties of R210 and R213, without significant movement of the S4.

Excitable tissues accomplish their signaling functions thanks in part to the interplay of several voltage-sensitive ion channels (1–6). Hence, to understand these processes, it is crucial to establish how voltage-sensitive ion channels sense changes in the electric field across the membrane, an issue that has been a matter of extensive study and intense debate for decades. The most widely accepted mechanism proposes the existence of voltage-sensor domains (VSDs), modules that undergo two or more discrete conformational states in response to changes in the membrane voltage. The simplest model considers two states: active (A), which promotes pore opening, and resting (R), which promotes channel closing. To accomplish its function, VSDs contain voltage-sensitive particles, which move in response to changes in the electric field. This movement triggers the interconversion between the two discrete conformational states. These voltage-sensing particles are typically the guanidine groups of arginine residues within the S4 transmembrane segment, which undergo a combination of rotational, translational, and tilting movement in response to changes in membrane voltage (7–14).The large-conductance Ca²⁺- and voltage-activated K⁺ (BK) channels have a wide distribution in mammalian tissues (15–18), where they participate in a diversity of physiological processes. Their malfunction is often related to diverse pathological conditions (19, 20). BK channel open probability is independently regulated by membrane depolarization and intracellular Ca²⁺ concentration (21, 22), each stimulus being detected by specialized modules. Like other voltage-sensitive K⁺ (Kv) channels, BK is an homotetramer in which each of its α subunits consists of a pore domain (PD; S5-S6 transmembrane segments), a voltage-sensing domain (VSD; S1–S4 transmembrane segments) containing a positively charged S4, and a cytosolic C-terminal regulatory domain, which contains the Ca²⁺-binding sites (23, 24). Also, like some members of other K⁺ channel families (25, 26), the VSD and PD of BK are non–domain swapped (23, 24). BK channels display some distinctive structural and functional features: Despite sharing the selectivity filter sequence with Kv channels, BK unitary conductance and selectivity are exquisitely high (27–30). The BK α subunit has an additional transmembrane segment S0 [therefore, its N terminus faces the extracellular medium (31)], and the voltage sensitivity in BK channels is significantly lower than that of Kv channels, presumably because of their lower number of gating charges (32).Although thoroughly studied, research into BK VSD and its voltage dependence has faced several technical obstacles. The relatively small gating charge per channel (32) and the large conductance of the BK pore makes isolating of the gating currents from the ionic currents a tough experimental challenge. In addition, because mutations of VSD residues can produce very large shifts in both the gating charge-voltage (Q(V)) and the conductance-voltage G(V)) relationships (33), it is necessary to use extreme voltages to accurately measure the voltage dependence of some mutants. Consequently, the identification of BK gating charges has been addressed by using indirect approaches (33, 34). The combination of electrophysiology measurements and kinetic modeling suggests a decentralized VSD in the BK channel, where four charged residues (D153 and R167 in S2, D186 in S3, and R213 in S4) act as voltage sensor particles (33). A recent report of the atomistic cryo-electron microscopy (cryo-EM) structures of the human BK channel and its homolog in Aplysia californica (AcSlo) revealed minor structural differences between the VSD in both the Ca²⁺-bound (open pore) and the Ca²⁺-unbound (closed pore) conformations (23, 24, 35). This result can be explained if the conformational changes of the BK VSD upon activation are small compared to those that occur during the activation of other channels, such as HCN channels (12–14).In this study, we identified voltage-sensing particles in the BK channel by using a direct functional approach, involving gating of current measurements and analysis of the Q(V) curves spanning 800 mV in the voltage axis. Systematic neutralization of the individual charged residues in the VSD (S1–S4) revealed that only the neutralization of two arginines in S4 (R210 and R213) changed the voltage dependence of the Q(V) curves. Neutralization of other VSD charges point to roles in tuning of the half-activation voltage of the VSD and its allosteric coupling with the PD. Molecular dynamics (MD) simulations based on the cryo-EM structures of the human BK channel (35) as templates suggested that R210 and R213 lie in a very narrow septum separating intra- and extracellular water-filled vestibules. This interpretation is consistent with the robust hyperpolarization-activated proton currents generated when R210 is mutated to the protonable amino acid histidine. Overall, our results point to a unique and distinctive mode of activation in BK: In contrast to Kv channels, where positive charges move one by one through a charge transfer center (absent in BK channels) that spans the entire electric field (36, 37), charge movement in BK channels is limited to the small displacement of R210 and R213, which itself constitutes a narrow septum where the electric field drops.     

Differential Effects of Three Nutritional Supplements on the Nutrient Intake of Pregnant Women Enrolled in a Conditional Cash Transfer Program in Mexico: A Cluster Randomized Trial

Supplementation in malnourished pregnant women should not displace natural healthy foods. Objective: To estimate the differential effects of three nutritional supplements on macro- and micronutrient intake of pregnant women beneficiaries of the conditional cash transfer program Prospera (CCT-POP). Methods: Prospective cluster randomized trial. Communities were randomly assigned to receive a fortified beverage (Beverage), micronutrient tablets (Tablets), or micronutrient powder (MNP). Pregnant women (at <25 weeks) were recruited. The food frequency questionnaire was applied at 25 and 37 weeks of pregnancy and at one and three months postpartum (mpp). Differential effects of the three supplements on the median change in nutrient intake from baseline to each follow-up stage were estimated. Results: Median change in protein intake from dietary and supplement sources were significantly lower for MNP and Tablets than for Beverages (baseline to 37 w: −7.80 ± 2.90 and −11.54 ± 3.00, respectively; baseline to 1 mpp: −7.34 ± 2.90 for MNP, p < 0.001). Compared to Beverages, median increases were higher for the MNP for vitamins C (31.2 ± 11.7, p < 0.01), E (1.67 ± 0.81, p < 0.05), and B12 (0.83 ± 0.27, p < 0.01) from baseline to 37 wk; from baseline to 1 mpp, there was a higher median increase in B12 (0.55 ± 0.25, p < 0.05) and folate (63.4 ± 24.3, p < 0.01); and from baseline to 3 mpp, a higher median increase in iron (2.38 ± 1.06, p < 0.05) and folate (94.4 ± 38.1, p < 0.05). Conclusions: Intake of micronutrients was higher for MNP and Tablets, likely due to food displacement among Beverage consumers. Although iron bioavailability and absorption inhibitors were not considered for the present analyses, the distribution of Tablets or MNP had several advantages in this context where micronutrient deficiency remains high among pregnant women, but macronutrient intake is generally adequate or even high.