Methylene blue dye for identification of processus vaginalis during hydrocele repair: experience in a teaching hospital.

BACKGROUND: The aim of this study is to investigate the use of methylene blue in perioperative identification of the patent processus vaginalis in a group of boys presenting with congenital or recurrent hydrocele where surgery was performed by junior surgeons in training. METHODS: We retrospectively reviewed the notes of 22 boys with hydrocele, of which two recurrences, who were operated via a standard inguinal approach, by trainees. Methylene blue 0.3-0.5 mL was injected into the hydrocele fluid through the scrotal wall. A processus vaginalis was identified as a blue line. RESULTS: Methylene blue injection clearly identified a patent processus vaginalis in 91% of patients. In 9% (N.=2), of which one recurrence, methylene blue injection demonstrated a hydrocele with an obliterated processus vaginalis. There were no intraoperative complications. No testicular atrophy was recorded. CONCLUSIONS: Injection of methylene blue into the hydrocele sac may be considered a useful aid for a clearer identification of a difficult patent processus vaginalis. In the present series, there were no complications, and thus we believe that this technique might be suitable and especially helpful, in cases of recurrent hydrocele, and for junior surgeons in training.

[Analysis of Quality Management of in Vitro Diagnostic Reagent Clinical Trials].

Clinical trial is an important step of in vitro diagnostic reagents research and development. Based on the Guiding Principles and the key points of inspect on the spot, combined with the actual work experience, the article focuses on the prominent problems in the whole process of in vitro diagnostic reagent clinical trials. It is helpful to improve the level of hospital drug clinical trial centre and the quality of in vitro diagnostic reagent clinical trials by analyzing the issues.

Development and Validation of a Fast Ultra-High Performance Liquid Chromatography-Fluorescent Method for the Quantification of Hydroxychloroquine and Its Metabolites in Patients With Lupus.

BACKGROUND: Hydroxychloroquine (HCQ) is approved for the treatment of systemic lupus erythematosus (SLE). Therapeutic drug monitoring of HCQ is necessary to detect nonadherence and to improve treatment efficacy in patients with SLE. Liquid chromatographic-tandem mass spectroscopy and high performance liquid chromatography (HPLC)-fluorescent methods are currently used to measure whole blood concentrations of HCQ and its 2 main metabolites desethylhydroxychloroquine and desethylchloroquine in patients with SLE. This study reports the development and validation of an ultra-HPLC (U-HPLC) method with fluorescence detection for the simultaneous quantification of HCQ and its metabolites in whole blood. METHODS: After adding chloroquine (internal standard) to the samples, a single-step protein precipitation and a subsequent filtration were used for blood sample preparation. Analytes were separated under isocratic elution on a U-HPLC RP18 column with a total run time of 7 minutes. The mobile phase consisted of piperazine buffer (46.4 mM, pH = 9.8) and acetonitrile (68:32, vol/vol), which was delivered at a flow rate of 0.4 mL/min. Fluorescence excitation and emission wavelengths were 335 and 390 nm, respectively. Assay performance parameters were evaluated per FDA bioanalytical guidelines. RESULTS: The calibration curve was linear from 125 to 4000 ng/mL for HCQ. The lower limit of quantification was 10 ng/mL for all analytes. For HCQ, desethylchloroquine, and desethylhydroxychloroquine, accuracies and imprecisions ranged from -7.90% to 7.85% and 1.14% to 8.78%, respectively. CONCLUSIONS: A sensitive, accurate, and fast U-HPLC-fluorescent method was validated and successfully applied to quantify whole blood concentrations to perform therapeutic drug monitoring of HCQ in pediatric and adult lupus patients.

INFLUENCE OF INVERTED INTERNAL LIMITING MEMBRANE FLAP TECHNIQUE ON THE OUTER RETINAL LAYER STRUCTURES AFTER A LARGE MACULAR HOLE SURGERY.

PURPOSE: To examine the influence of inverted internal limiting membrane (ILM) flap technique on the outer retinal layer structures after macular hole (MH) surgery. METHODS: We included 24 eyes of 24 patients who underwent vitrectomy for large MHs (≥400 µm) with successful MH closure and observed for at least 6 months. Fourteen eyes were treated with inverted ILM flap technique (inverted group) and 10 with conventional ILM peeling (ILMP group). We evaluated the postoperative recovery rate of the external limiting membrane and ellipsoid zone and the best-corrected visual acuity. RESULTS: The postoperative recovery rates of the external limiting membrane and ellipsoid zone in the inverted group were lower than those in the ILMP group (21.4 vs. 70.0%, P = 0.024; 0 vs. 30.0, P = 0.059, respectively). The external limiting membrane recovery period in the inverted group was significantly longer than that in the ILMP group (11.0 ± 1.7 vs. 3.4 ± 2.8 months, P = 0.015). The best-corrected visual acuity change (letters) in the inverted group was significantly smaller than that in the ILMP group (9.0 vs. 22.5, P = 0.040). CONCLUSION: The poorer anatomical and visual results associated with inverted ILM flap compared with ILM peeling suggest the limitation of the ILM flap technique to repair refractory MHs.

An Analysis of Skin Test Responses to Spherulin-Based Coccidioidin (Spherusol®) Among a Group of Subjects with Various Forms of Active Coccidioidomycosis.

BACKGROUND: A reformulated skin test for coccidioidomycosis, Spherusol®, was recently approved for use in the USA. We hypothesized that it could be useful in predicting severity of illness and outcome in various types of coccidioidomycosis. METHODS: Subjects with non-meningeal coccidioidomycosis attending a clinic in the coccidioidal endemic region were skin tested with Spherusol® and clinical data were collected at the time of testing and at follow-up. RESULTS: Twenty-seven subjects were studied, eight of whom had extrathoracic dissemination. A total of 15 subjects had positive tests, including 11 of 19 subjects with non-disseminated pulmonary disease and four with extrathoracic disseminated coccidioidomycosis. Among those with non-disseminated pulmonary disease, age ≥ 65 years, female sex, and antifungal therapy were significantly associated with a negative test on univariate but not multivariate analysis. For 23 subjects, there was a trend for those not on antifungal therapy at the time of follow-up to have a positive test but no association with coccidioidal complement-fixation titer or overall outcome. CONCLUSIONS: Not all subjects with non-disseminated pulmonary coccidioidomycosis were found to be skin test positive and half of those with extrathoracic disseminated disease manifested dermal hypersensitivity. In this small study, the results of the skin test were not clinically predictive of disease severity or outcome.

Sodium nitrite augments lung S-nitrosylation and reverses chronic hypoxic pulmonary hypertension in juvenile rats.

Deficient nitric oxide (NO) signaling plays a critical role in the pathogenesis of chronic neonatal pulmonary hypertension (PHT). Physiological NO signaling is regulated by S-nitrosothiols (SNOs), which act both as a reservoir for NO and as a reversible modulator of protein function. We have previously reported that therapy with inhaled NO (iNO) increased peroxynitrite-mediated nitration in the juvenile rat lung, although having minimal reversing effects on vascular remodeling. We hypothesized that sodium nitrite (NaNO2) would be superior to iNO in enhancing lung SNOs, thereby contributing to reversal of chronic hypoxic PHT. Rat pups were exposed to air or hypoxia (13% O2) from postnatal days 1 to 21. Dose-response prevention studies were conducted from days 1-21 to determine the optimal dose of NaNO2. Animals then received rescue therapy with daily subcutaneous NaNO2 (20 mg/kg), vehicle, or were continuously exposed to iNO (20 ppm) from days 14-21. Chronic PHT secondary to hypoxia was both prevented and reversed by treatment with NaNO2. Rescue NaNO2 increased lung NO and SNO contents to a greater extent than iNO, without causing nitration. Seven lung SNO proteins upregulated by treatment with NaNO2 were identified by multiplex tandem mass tag spectrometry, one of which was leukotriene A4 hydrolase (LTA4H). Rescue therapy with a LTA4H inhibitor, SC57461A (10 mg·kg-1·day-1 sc), partially reversed chronic hypoxic PHT. We conclude that NaNO2 was superior to iNO in increasing tissue NO and SNO generation and reversing chronic PHT, in part via upregulated SNO-LTA4H.

Circular stripes were more common in Barrett's esophagus after acetic acid staining.

BACKGROUND: The diagnosis of Barrett's esophagus (BE) is disturbed by numerous factors, including correct gastroesophageal junction judgment, the initial location of the Z-line and the biopsy result above it. The acetic acid (AA) could help to diagnose BE better than high resolution imaging technology or magnifying endoscopy, by providing enhanced contrast of different epithelium. We have noticed AA could produce multiple white circular lines, forming circular stripes (CS), at lower esophagus, which hasn't been reported by others. This study aimed to investigate whether the CS is a special marker in BE patients. METHODS: A total of 47 BE patients and 63 healthy people were enrolled from March 2016 to October 2016, and 2% AA staining had been operated routinely at lower esophagus under high resolution gastroscopy. We observed whether there were CS after AA staining and the images were compared between the two groups. RESULTS: CS were confirmed in 42 patients (89.36%) in the BE group and 5 (7.94) in the control group ((χ2 = 72.931, P < 0.001)). The average width of CS was 0.76 ± 0.25 cm in BE group, which was similar to that in the control group (0.88 ± 0.11 cm). Villous or punctate or reticular pattern usually existed above or below the CS. CONCLUSIONS: CS could be found at lower esophagus in most BE patients with AA staining, and this special feature might be valuable in diagnosing, evaluating and following up of BE patients.

Accuracy of combinations of visual inspection using acetic acid or lugol iodine to detect cervical precancer: a meta-analysis.

BACKGROUND: Visual inspection of the cervix with acetic acid (VIA) or with Lugol's iodine (VILI) have been evaluated for cervical cancer screening in developing countries. OBJECTIVES: To assess the diagnostic accuracy and clinical utility of visual methods to detect cervical intraepithelial neoplasia grade 2+ (CIN2+) using: (1) VIA alone; (2) VILI alone; (3) co-testing; and (4) VILI as a triage test of a positive VIA result. SEARCH STRATEGY: PubMed, EMBASE, and the Cochrane Library were searched up to May 2016. SELECTION CRITERIA: All reports on the accuracy of VIA and VILI, or combinations of VIA/VILI, to detect CIN2+ were identified. Histology and colposcopy when no biopsy was taken were used as the reference standard. DATA COLLECTION AND ANALYSIS: Selected studies were scored on methodological quality, and sensitivity and specificity were computed. Clinical utility was assessed from the positive predictive value (PPV) and the complement of the negative predictive value (cNPV). MAIN RESULTS: We included 23 studies comprising 101 273 women. The pooled sensitivity and specificity of VILI was 88 and 86%, respectively. VILI was more sensitive, but not less specific, compared with VIA (relative sensitivity = 1.11; 95% confidence interval, 95% CI, 1.06-1.16; relative specificity = 0.98; 95% CI 0.95-1.01). Co-testing was hardly more sensitive, but significantly less specific, than VILI alone. VILI to triage VIA-POSITIVE women was not less sensitive, but more specific, compared with VIA alone (relative sensitivity = 0.98, 95% CI 0.96-1.01; relative specificity = 1.04, 95% CI 1.02-1.05). The average PPVs were low (range 11-16%), whereas the cNPV varied between 0.3% (VILI, co-testing) and 0.6% (triage). CONCLUSIONS: Although imperfect, VILI alone appeared to be the most useful visual screening strategy. TWEETABLE ABSTRACT: VILI alone seems to be the most useful visual screening test for cervical cancer screening.

Development and validation of a training module on the use of acetic acid for the detection of Barrett's neoplasia.

Background and study aims Acetic acid chromoendoscopy (AAC) enhances the ability to correctly identify Barrett's neoplasia, and is increasingly used by both expert and nonexpert endoscopists. Despite its increasing use, there is no validated training strategy to achieve competence. The aims of our study were to develop a validated training tool in AAC-assisted lesion recognition, to assess endoscopists' baseline knowledge of AAC-assisted lesion recognition, and to evaluate the efficacy and impact of this training tool. Methods A validated assessment of 40 images and 20 videos was developed. A total of 13 endoscopists with experience of Barrett's endoscopy but no formal training in AAC were recruited to the study. Participants underwent: baseline assessment 1, online training, assessment 2, interactive seminar, assessment 3. Results Baseline assessment demonstrated a sensitivity of 83 % and a negative predictive value (NPV) of 83 %. The online training intervention significantly improved sensitivity to 95 % and NPV to 94 % (P < 0.01). Further improvement was seen after a 1-day interactive seminar including live cases, with sensitivity increasing to 98 % and NPV to 97 %. Conclusions The data demonstrate the need for training in AAC-assisted lesion recognition as baseline performance, even by Barrett's experts, was poor. The online training and testing tool for AAC for Barrett's neoplasia was successfully developed and validated. The training intervention improved performance of endoscopists to meet ASGE PIVI standards. The training tool increases the endoscopist's degree of confidence in the use of AAC. The training tool also leads to shift in attitudes of endoscopists from Seattle protocol towards AAC-guided biopsy protocol for Barrett's surveillance.

BRILLIANT BLUE G-ASSISTED INTERNAL LIMITING MEMBRANE PEELING FOR MACULAR HOLE: A Systematic Review of Literature and Meta-Analysis.

PURPOSE: To evaluate the effect of internal limiting membrane peeling with brilliant blue G (BBG) for the treatment of macular hole compared with peeling procedures with other dyes or without dye. METHODS: MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) were systematically reviewed. Outcome measures were the primary closure rate and postoperative best-corrected visual acuity. RESULTS: Nine studies that included 846 eyes were selected. There was no significant difference in preoperative best-corrected visual acuity between the BBG and no BBG (i.e., other dyes or no dye) groups (mean difference -0.02 logMAR [equivalent to 1 Early Treatment Diabetic Retinopathy Study (ETDRS) letter]; 95% confidence interval -0.09 to 0.04 [-2-4.5 ETDRS letters]; P = 0.45). The macular hole closure rate using BBG was not significantly different from that using indocyanine green (odds ratio 1.98; 95% confidence interval 0.71-5.48; P = 0.19). The postoperative best-corrected visual acuity was more favorable with BBG than with indocyanine green (mean difference -0.10 logMAR [5 ETDRS letters]; 95% confidence interval -0.16 to -0.03 [1.5-8 ETDRS letters]; P = 0.004) or with no BBG (mean difference -0.11 [5.5 ETDRS letters]; 95% confidence interval -0.18 to -0.04 [2-9 ETDRS letters]; P = 0.003). CONCLUSION: BBG could contribute to better visual acuity outcome than other dyes for internal limiting membrane peeling in patients with macular hole; however, it does not significantly influence the closure rate.

HIGH-RESOLUTION MULTIMODAL IMAGING AFTER IDIOPATHIC EPIRETINAL MEMBRANE SURGERY.

PURPOSE: To investigate the changes of the vitreomacular interface during a 1-year follow-up after idiopathic epiretinal membrane (iERM) surgery. METHODS: Six patients affected by fovea-attached iERM were recruited in this pilot study. Pars plana vitrectomy associated with epiretinal membrane peeling was performed uneventfully in all cases. In four cases, the inner limiting membrane was removed using Brilliant blue G. En face high-resolution adaptive optics and cross-sectional spectral domain optical coherence tomography retinal imaging were performed before and at 1, 3, 6, and 12 months after surgery. The microstructures of vitreomacular interface in high-resolution adaptive optics images were correlated to the cross-sectional spectral domain optical coherence tomography data. RESULTS: Preoperatively, adaptive optics images showed multiple abnormalities of the vitreomacular interface, such as macrofolds, microfolds, and hyperreflective microstructures. We identified two subtypes of iERM according to the distribution of microfolds over the foveal area, which included the radial-type and the grid-type iERM. After surgery, the morphology of the vitreomacular interface changed compared with the preoperative state. The number of both macrofolds and microfolds was reduced in all cases. The hyperreflective structures were still resolvable in all cases, however presenting different shape and morphology than preoperatively. In addition, they showed marked differences between eyes that had internal limiting membrane removal and eyes that did not. CONCLUSION: Adaptive optics imaging gives new insight into the changes of vitreomacular interface after iERM surgery. Enhanced multimodal imaging of the vitreomacular interface and retinal structures can be valuable to monitor treatment outcome of iERM.

mHealth to Train Community Health Nurses in Visual Inspection With Acetic Acid for Cervical Cancer Screening in Ghana.

OBJECTIVE: There is a shortage of trained health care personnel for cervical cancer screening in low-/middle-income countries. We evaluated the feasibility and limited efficacy of a smartphone-based training of community health nurses in visual inspection of the cervix under acetic acid (VIA). MATERIALS AND METHODS: During April to July 2015 in urban Ghana, we designed and developed a study to determine the feasibility and efficacy of an mHealth-supported training of community health nurses (CHNs, n = 15) to perform VIA and to use smartphone images to obtain expert feedback on their diagnoses within 24 hours and to improve VIA skills retention. The CHNs completed a 2-week on-site introductory training in VIA performance and interpretation, followed by an ongoing 3-month text messaging-supported VIA training by an expert VIA reviewer. RESULTS: Community health nurses screened 169 women at their respective community health centers while receiving real-time feedback from the reviewer. The total agreement rate between all VIA diagnoses made by all CHNs and the expert reviewer was 95%. The mean (SD) rate of agreement between each CHN and the expert reviewer was 89.6% (12.8%). The agreement rates for positive and negative cases were 61.5% and 98.0%, respectively. Cohen κ statistic was 0.67 (95% CI = 0.45-0.88). Around 7.7% of women tested VIA positive and received cryotherapy or further services. CONCLUSIONS: Our findings demonstrate the feasibility and efficacy of mHealth-supported VIA training of CHNs and have the potential to improve cervical cancer screening coverage in Ghana.

Contrast-Induced Acute Kidney Injury: Comparison of Preventative Therapies.

Contrast medium is used daily for diagnostic and interventional procdures as a means to visualize blood vessels. The administration of contrast dye, however, can lead to an acute reduction in kidney function. This complication can impact length of hospital stay, risk of dialysis, and increased hospital mortality. Common preventative measures include N-acetylcysteine and intravenous hydration. The evidence reviewed revealed hydration to be the more effective treatment to reduce the risk of acute kidney injury.

Hepatic insulin sensitivity in healthy and prediabetic subjects: from a dual- to a single-tracer oral minimal model.

Recently, a model was proposed to assess hepatic insulin sensitivity during a meal, i.e., the ability of insulin to suppress glucose production (EGP), SI (P). The model was developed on EGP data obtained from a triple-tracer meal and the tracer-to-tracee clamp technique and validated against the euglycemic hyperinsulinemic clamp. The aim of this study was to assess whether SI (P) can be obtained from plasma concentrations measured after a single-tracer meal by incorporating the above EGP model into the oral glucose minimal model by describing both glucose production and disposal (OMM(PD)). Triple-tracer meal data of two databases (20 healthy and 60 healthy and prediabetic subjects) were used. Virtually model-independent EGP estimates were calculated. OMM(PD) was identified on exogenous and endogenous glucose concentrations, providing indices of SI (P), disposal insulin sensitivity (SI (D)), and EGP. The model fitted the data well, and SI (P) and SI (D) were estimated with precision in both databases (SI (P) = 5.48 ± 0.54 10(-4) dl·kg(-1)·min(-1) per µU/ml and SI (D) = 9.93 ± 2.18 10(-4) dl·kg(-1)·min(-1) per µU/ml in healthy; SI (P) = 5.41 ± 3.55 10(-4) dl·kg(-1)·min(-1) per µU/ml and SI (D) = 5.34 ± 6.17 10(-4) dl·kg(-1)·min(-1) per µU/ml, in healthy and prediabetic subjects). Estimated SI (P) and that derived from the triple-tracer EGP model were very similar on average. Moreover, the time course of EGP normalized to basal EGP (EGPb), and EGP/EGPb agreed with the results obtained using the triple-tracer method. In this study, we have demonstrated that SI (P), SI (D), and EGP/EGPb time course can be estimated reliably from a single-tracer meal protocol in both healthy and prediabetic subjects.

Analysis of the intra- and intertumoral heterogeneity of hypoxia in pancreatic cancer patients receiving the nitroimidazole tracer pimonidazole.

BACKGROUND: Hypoxia is thought to be an adverse feature of pancreatic cancer, but direct measurement in patients is technically challenging. To address this, we characterised the intra/interpatient heterogeneity of hypoxia in surgical specimens from patients who received the 2-nitroimidazole tracer pimonidazole pre-operatively. METHODS: Pimondazole was given intravenously 16-20 h before pancreatectomy, and the extent and intratumoral heterogeneity of hypoxia determined by image analysis applied to multiple tissue blocks stained by immunohistochemistry. Intra/interpatient heterogeneity was estimated by variance component analysis. RESULTS: Pimonidazole staining was analysed in 10 tumours. The extent of labelling varied amongst patients (0-26%), with a broader range of hypoxia in the epithelial (1-39%) compared with the stromal (1-13%) compartments. Variance component analysis demonstrated greater inter- than intrapatient variability of hypoxia, and that multiple (4-5) tumour sections are required to provide a consistent evaluation of its extent in individual tumours. CONCLUSIONS: There is significant intra- and intertumoral heterogeneity of hypoxia in pancreatic cancers, and these do not appear to be generally more hypoxic than other cancer types. This study establishes the feasibility to assess hypoxia in pancreatic cancer patients using pimonidazole, but questions the reliability of measurements made using a single tissue section.

RNAi in murine hepatocytes: the agony of choice--a study of the influence of lipid-based transfection reagents on hepatocyte metabolism.

Primary hepatocyte cell cultures are widely used for studying hepatic diseases with alterations in hepatic glucose and lipid metabolism, such as diabetes and non-alcoholic fatty liver disease. Therefore, small interfering RNAs (siRNAs) provide a potent and specific tool to elucidate the signaling pathways and gene functions involved in these pathologies. Although RNA interference (RNAi) in vitro is frequently used in these investigations, the metabolic alterations elucidated by different siRNA delivery strategies have hardly been investigated in transfected hepatocytes. To elucidate the influence of the most commonly used lipid-based transfection reagents on cultured primary hepatocytes, we studied the cytotoxic effects and transfection efficiencies of INTERFERin(®), Lipofectamine(®)RNAiMAX, and HiPerFect(®). All of these transfection agents displayed low cytotoxicity (5.6-9.0 ± 1.3-3.4%), normal cell viability, and high transfection efficiency (fold change 0.08-0.13 ± 0.03-0.05), and they also favored the satisfactory down-regulation of target gene expression. However, when effects on the metabolome and lipidome were studied, considerable differences were observed among the transfection reagents. Cellular triacylglycerides levels were either up- or down-regulated [maximum fold change: INTERFERin(®) (48 h) 2.55 ± 0.34, HiPerFect(®) (24 h) 0.79 ± 0.08, Lipofectamine(®)RNAiMAX (48 h) 1.48 ± 0.21], and mRNA levels of genes associated with lipid metabolism were differentially affected. Likewise, metabolic functions such as amino acid utilization from were perturbed (alanine, arginine, glycine, ornithine, and pyruvate). In conclusion, these findings demonstrate that the choice of non-viral siRNA delivery agent is critical in hepatocytes. This should be remembered, especially if RNA silencing is used for studying hepatic lipid homeostasis and its regulation.

A comparison of two visual inspection methods for cervical cancer screening among HIV-infected women in Kenya.

OBJECTIVE: To determine the optimal strategy for cervical cancer screening in women with human immunodeficiency virus (HIV) infection by comparing two strategies: visual inspection of the cervix with acetic acid (VIA) and VIA followed immediately by visual inspection with Lugol's iodine (VIA/VILI) in women with a positive VIA result. METHODS: Data from a cervical cancer screening programme embedded in two HIV clinic sites in western Kenya were evaluated. Women at a central site underwent VIA, while women at a peripheral site underwent VIA/VILI. All women positive for cervical intraepithelial neoplasia grade 2 or worse (CIN 2+) on VIA and/or VILI had a confirmatory colposcopy, with a biopsy if necessary. Overall test positivity, positive predictive value (PPV) and the CIN 2+ detection rate were calculated for the two screening methods, with biopsy being the gold standard. FINDINGS: Between October 2007 and October 2010, 2338 women were screened with VIA and 1124 with VIA/VILI. In the VIA group, 26.4% of the women tested positive for CIN 2+; in the VIA/VILI group, 21.7% tested positive (P < 0.01). Histologically confirmed CIN 2+ was detected in 8.9% and 7.8% (P = 0.27) of women in the VIA and VIA/VILI groups, respectively. The PPV of VIA for biopsy-confirmed CIN 2+ in a single round of screening was 35.2%, compared with 38.2% for VIA/VILI (P = 0.41). CONCLUSION: The absence of any differences between VIA and VIA/VILI in detection rates or PPV for CIN 2+ suggests that VIA, an easy testing procedure, can be used alone as a cervical cancer screening strategy in low-income settings.

Efficacy of calcein and Coomassie Blue dyeing of shell growing-edges and micro growth-bands: ageing juvenile of Pinctada mazatlanica (Pterioida: Pteriidae).

Age validation is the first step to determine shellfish species age determination. This information is vital for different inferential models used in marine ecosystem management activities. In spite that various validation techniques are used for marking carbon calcium structures, the calcein marking technique for oysters had never been used for age validation in Pinctada mazatlanica. Thus the objectives of this study included: the evaluation of calcein to mark a shell growing-edge, and the efficacy of Coomassie Blue staining on posterior shell growth, to produce visible micro growth-bands that would enable age validation of juvenile mother-of-pearl oysters. Oysters were collected and cultivated at The Perlas del Cortez S. de R. L. MI. pearl-farming operation, in Pichilingue, La Paz Bay, Baja California Sur, Mexico; a total of 36 oysters (shell height 11.5-36.4 mm) were injected with calcein (0.125 g/L), and another 50 oysters (shell height 14.8-42.7 mm) were submersed in calcein (0.4 and 0.7 g/L). Shell slices of calcein-marked oysters were posteriourly stained with Coomassie Blue R-25 for micro growth-band recognition. Our results showed that Calcein marking only worked by submersion and produced a concise bright lime-green florescent band along the growing-edge with clear boundaries for both concentrations. However, marks resulted better at the lower calcein concentration (0.4 g/L) with more "perfect" and "good" marks on the growing-edge (p = 0.0012). Commassie Blue staining technique was successful, and allowed to conclude that one micro growth-band was laid down per day, similar to other oyster species. Mean 15-d increment of shell growth height was slightly greater at the lower calcein concentration (= 0.735 mm) than at the higher one (= 0.577 mm) (not significant difference, p = 0.198). Calcein marking of shell growing-edges and Commassie Blue staining of posterior shell growth, as a method for age validation is recommended for shellfish shell growth-band counts. This will allow back-dating for estimation of very precise colonization dates, both spatially and temporally in future work.

Towards chemical communication between gated nanoparticles.

The design of comparatively simple and modularly configurable artificial systems able to communicate through the exchange of chemical messengers is, to the best of our knowledge, an unexplored field. As a proof-of-concept, we present here a family of nanoparticles that have been designed to communicate with one another in a hierarchical manner. The concept involves the use of capped mesoporous silica supports in which the messenger delivered by a first type of gated nanoparticle is used to open a second type of nanoparticle, which delivers another messenger that opens a third group of gated nanoobjects. We believe that the conceptual idea that nanodevices can be designed to communicate with one another may result in novel applications and will boost further advances towards cooperative systems with complex behavior as a result of the communication between simple abiotic individual components.