Andalusian Public Eye-Banks: a decade of continuous improvement.

OBJECTIVES: To show donation data, number of keratoplasties and the changes in transplant indications and techniques that occurred in Andalusia in the period from 2013 to 2022. MATERIALS AND METHODS: The present work is a retrospective and descriptive study that included all keratoplasties performed between January 2013 and December 2022 in Andalusia, as well as the evolution of the cornea donation and transplant activity of the public and private hospitals pertaining to the waiting list management system of the Public Health System of Andalusia. Transplants performed in private centers with corneas from outside Andalusia were excluded. RESULTS: Cornea donation activity in Andalusia in the decade 2013-2022 has experienced a growth of more than 126%, while overall transplant activity has increased by 157% in public hospitals. Penetrating keratoplasty has decreased from 83% in 2013 to 43% in 2022, while lamellar techniques have increased from 17% to 57% in this same period. Since 2018, more lamellar transplants are performed than penetrating transplants. Regarding indications, endothelial conditions already represent the first cause of transplantation. In 2022 alone, the public Andalusian Eye Banks evaluated 1,054 corneas and prepared 281 endothelial grafts. CONCLUSION: In the decade from 2013 to 2022 in Andalusia there has been an increase in donation activity and the number of keratoplasties. The public Eye Banks implementation in this period has played a key role in the widespread adoption of lamellar keratoplasty techniques and has enabled the transition to perform a greater number of lamellar keratoplasties compared to penetrating keratoplasty.

Total and bioavailable arsenic concentration in arid soils and its uptake by native plants from the pre-Andean zones in Chile.

Arsenic is the most important contaminant of the environment in northern Chile. Soil samples and plant organs from three native plant species, Pluchea absinthioides, Atriplex atacamensis and Lupinus microcarpus, were collected from arid zones in order to determine the total and bioavailable arsenic concentrations in soils and to assess the bioconcentration factor (BCF) and transport index (Ti) of arsenic in the plants. Total arsenic concentrations in soils (pH 8.3-8.5) where A. atacamensis and P. absinthioides were collected, reached levels considered to be contaminated (54.3 ± 15.4 and 52.9 ± 9.9 mg kg⁻¹, respectively), and these values were approximately ten times higher than in soils (pH 7.6) where L. microcarpus was collected. Bioavailable arsenic ranged from 0.18 to 0.42% of total arsenic concentration. In the three plant species, arsenic concentration in leaves were significantly (p ≤ 0.05) higher than in roots. L. microcarpus showed the highest arsenic concentration in its leaves (9.7 ± 1.6 mg kg⁻¹) and higher values of BCF (1.8) and Ti (6.1), indicating that this species has a greater capacity to accumulate and translocate the metalloid to the leaf than do the other species.

Cellular and functional recovery of Parkinsonian rats after intrastriatal transplantation of carotid body cell aggregates.

We have tested the suitability of chromaffin-like carotid body glomus cells for dopamine cell replacement in Parkinsonian rats. Intrastriatal grafting of cell aggregates resulted in almost optimal abolishment of motor asymmetries and deficits of sensorimotor orientation. Recovery of transplanted animals was apparent 10 days after surgery and progressed throughout the 3 months of the study. The behavioral effects were correlated with the long survival of glomus cells in the host brain. In host tissue, glomus cells were organized into glomerulus-like structures and retained the ability to secrete dopamine. Several weeks after transplantation, dopaminergic fibers emerged from the graft, reinnervating the striatal gray matter. The special durability of grafted glomus cells in the conditions of brain parenchyma could be related to their sensitivity to hypoxia, which is known to induce cell growth, excitability, and dopamine synthesis. This work should stimulate research on the clinical applicability of carotid body autotransplants in Parkinson's disease.

Recovery of chronic parkinsonian monkeys by autotransplants of carotid body cell aggregates into putamen.

We have studied the effect of unilateral autografts of carotid body cell aggregates into the putamen of MPTP-treated monkeys with chronic parkinsonism. Two to four weeks after transplantation, the monkeys initiated a progressive recovery of mobility with reduction of tremor and bradykinesia and restoration of fine motor abilities on the contralateral side. Apomorphine injections induced rotations toward the side of the transplant. Functional recovery was accompanied by the survival of tyrosine hydroxylase-positive (TH-positive) grafted glomus cells. A high density of TH-immunoreactive fibers was seen reinnervating broad regions of the ipsilateral putamen and caudate nucleus. The nongrafted, contralateral striatum remained deafferented. Intrastriatal autografting of carotid body tissue is a feasible technique with beneficial effects on parkinsonian monkeys; thus, this therapeutic approach could also be applied to treat patients with Parkinson's disease.

As2O3-induced oxidative stress and cycle progression in a human intestinal epithelial cell line (Caco-2).

Foods and drinking water are the main routes for human exposure to inorganic arsenic, the intestinal epithelium being the first barrier against such exogenous toxicants. The present study evaluates the effect of As(III) (0.5-25 microM) upon Caco-2 cells as an intestinal epithelia model. Cell viability, intracellular formation of reactive oxygen species (ROS), mitochondrial membrane potential (Deltapsim) changes, and cell cycle distribution in exposed cultures were evaluated. The intracellular production of ROS was seen to increase in a non-dose dependent manner at all concentrations tested, with impairment of cell mitochondrial enzyme function secondary to a loss of Deltapsim. Concentrations between 0.5 and 5 microM induce cell cycle transition from phase G1 to phase S, with no significant alteration in the proportion of cells in phase G2. These data suggest that As(III) could induce intestinal oxidative stress-cytotoxicity at mitochondrial functional level, and affect cell cycle progression. The data presented in this work may also suggest the impairment of essential survival processes in Caco-2 cells, induced after exposure to As(III) (1-25 microM). Oxidative stress and alteration of mitochondrial functionality could be early indicators of arsenic-induced cytotoxicity, with the resulting abnormal progression of the cell cycle.

Effect of thermal treatments on arsenic species contents in food.

In arsenic-endemic and other areas, food is an important path of exposure to this contaminant. Food is generally consumed in processed form, after a preservation treatment or cooking, which may alter the concentrations and chemical forms of arsenic. This article summarizes and discusses the work so far published on the effect that thermal treatment used in the cooking or processing of food, including sterilization and preservation stages, has on total arsenic and arsenic species contents. It also reviews possible transformations in arsenic species. The studies included use model systems or food products of marine or vegetable origin. Processing may cause a considerable increase or decrease in the real arsenic intake from food. For example, traditional washing and soaking of Hizikia fusiforme seaweed, which has very high inorganic arsenic contents, may reduce the contents by up to 60%. On the other hand, all the arsenic present in cooking water may be retained during boiling of rice, increasing the contents of this metalloid to significant levels from a toxicological viewpoint. This calls for modifications in arsenic risk assessment, hitherto based on analysis of the raw product. It is necessary to consider the effect of processing on total arsenic and arsenical species in order to obtain a realistic view of the risk associated with intake in arsenic-endemic and other areas.

Prediction of calibration curves in ria of digoxin; Influence of some variables.

BACKGROUND: Competitive protein binding radioimmunoassay (CPB-RIA) is a principal method for quantifying serum digoxin concentration. The accuracy of this method is critically dependent on factors that influence the substitution reaction between unlabelled (Q) antigen (digoxin) with (125)I-labelled antigen (M) bound to anti-digoxin antibody (P). We studied the influence of initial concentration of M, ionic strength, and viscosity on the substitution reaction between M and Q. In addition, we propose a kinetic model for this reaction. METHODS: We used a commercially available CPB-RIA for digoxin, a gamma counter, and a viscosimeter to study the effect of initial concentration of M, ionic strength, viscosity, and temperature on the substitution reaction between M and Q. Data were analyzed using Statistica software. RESULTS: The apparent rate constant for the reaction between M and Q in the formation of PM is dependent on the initial concentration of M, and the ionic strength, viscosity, and temperature of the reaction medium, and independent of the concentration of Q. CONCLUSION: A kinetic model for the displacement of the (125)I-digoxin by the digoxin in its union to a specific antibody is proposed. Such model adjusts satisfactorily to the results and allows the prediction of the calibration curves of RIA (activity bound to the antibody vs. concentration of digoxin) showing the influence of the concentration of both species, the time of incubation, the viscosity and the ionic strength of the medium, on the sensitivity of the method of RIA on which the analytical determination of the digoxin is based.

Bioaccessibility and transport by Caco-2 cells of organoarsenical species present in seafood.

Organoarsenical standards and raw and cooked seafood (DORM-2, sole, and Greenland halibut) were subjected to in vitro gastrointestinal digestion to estimate arsenic bioaccessibility (maximum soluble concentration in gastrointestinal medium). The in vitro digestion did not modify the chemical form of the organoarsenic species standards. In seafood, bioaccessibility was 67.5-100% for arsenobetaine (AB), 30% for dimethylarsinic acid (DMA), 45% for tetramethylarsonium ion (TETRA), and >50% for trimethylarsine oxide (TMAO). Cooking induced no changes in bioaccessible contents. In addition, transport by Caco-2 cells, an intestinal epithelia model, was evaluated from organoarsenical standards and DORM-2. For standards, transport ranged from 1.7% for AB to 15.5% for TETRA. In DORM-2, transport was observed for only AB (12%), with far higher efficiency than in the case of the standard solution, thus illustrating the interest of using whole foods for studying bioavailability.

Oxygen sensing by ion channels and chemotransduction in single glomus cells.

We have monitored cytosolic [Ca2+] and dopamine release in intact fura-2-loaded glomus cells with microfluoroimetry and a polarized carbon fiber electrode. Exposure to low PO2 produced a rise of cytosolic [Ca2+] with two distinguishable phases: an initial period (with PO2 values between 150 and approximately 70 mm Hg) during which the increase of [Ca2+] is very small and never exceeds 150-200 nM, and a second phase (with PO2 below approximately 70 mm Hg) characterized by a sharp rise of cytosolic [Ca2+]. Secretion occurs once cytosolic [Ca2+] reaches a threshold value of 180 +/- 43 nM. The results demonstrate a characteristic relationship between PO2 and transmitter secretion at the cellular level that is comparable with the relation described for the input (O2 tension)output (afferent neural discharges) variables in the carotid body. Thus, the properties of single glomus cells can explain the sensory functions of the entire organ. In whole-cell, patch-clamped cells, we have found that in addition to O2-sensitive K+ channels, there are Ca2+ channels whose activity is also regulated by PO2. Ca2+ channel activity is inhibited by hpoxia, although in a strongly voltage-dependent manner. The average hypoxic inhibition of the calcium current in 30% +/- 10% at -20 mV but only 2% +/- 2% at +30 mV. The differential inhibition of K+ and Ca2+ channels by hypoxia helps to explain why the secretory response of the cells is displaced toward PO2 values (below approximately 70 mm Hg) within the range of those normally existing in arterial blood. These data provide a conceptual framework for understanding the cellular mechanisms of O2 chemotransduction in the carotid body.

Organoarsenical species contents in cooked seafood.

The organoarsenical species arsenobetaine (AB), arsenocholine (AC), tetramethylarsonium ion (TMA+), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) were determined in 64 cooked seafood products (fish, bivalves, squid, crustaceans) included in a Total Diet Study carried out in the Basque Country (Spain). For cooking, various treatments were employed (grilling, roasting, baking, stewing, boiling, steaming, microwaving). The results obtained show that in cooked seafood AB is the major species, followed by DMA and TMA+. AC and MMA are minor species. The results in cooked seafood were compared with the arsenic species contents obtained for the same product raw. After cooking there was an increase in DMA for sardines and bivalves and an increase or appearance of TMA+ for meagrim, anchovy, Atlantic horse mackerel, and sardine. The data provided add to the very scant information available about organoarsenical species contents in cooked seafood.

N-methyl-D-aspartate stimulates the dephosphorylation of the microtubule-associated protein 2 and potentiates excitatory synaptic pathways in the rat hippocampus.

We have studied the effect of brief (50-150 s) applications of N-methyl-D-aspartate (10-100 microM) on the phosphorylated state of the microtubule-associated protein 2 in slices of rat hippocampus. Following a similar experimental protocol we also studied the pattern of excitatory postsynaptic potentials intracellularly recorded in CA1 pyramidal cells elicited by stimulation of the Schaffer collateral-commissural pathway. N-Methyl-D-aspartate treatment produced a marked and specific dephosphorylation of the cytoskeletal microtubule-associated protein 2, which was not due to enhanced proteolytic activity. Dephosphorylation of the microtubule-associated protein 2 affects mainly the tubulin-binding domain of the molecule and seems to be a consequence of the activation of the Ca2+/calmodulin-dependent phosphatase calcineurin, as it is partially inhibited by calmidazolium but not by okadaic acid. A few minutes after N-methyl-D-aspartate treatment we observed a 23 +/- 17% increase in the amplitude of the monosynaptic excitatory postsynaptic potential recorded in the cells and the appearance of a large polysynaptic excitatory postsynaptic potential. Both effects lasted for several tens of minutes. The late polysynaptic potential was not observed when the CA3 and CA1 subfields were surgically separated. Our results indicate that the N-methyl-D-aspartate receptor activation leads to the dephosphorylation of the microtubule-associated protein 2 via a Ca2+/calmodulin phosphatase, probably calcineurine. This may, in turn, participate in the potentiation of synaptic efficacy.

Comparison of two strategies for intensifying antihypertensive treatment: low-dose combination (enalapril + felodipine ER) versus increased dose of monotherapy (enalapril). LEVEL (Lexxel vs Enalapril) Study Group.

To compare two popular strategies for intensifying treatment for hypertension, a double-blind, randomized, prospective, parallel-group, and partial crossover study was done. After 2 weeks of placebo run-in (baseline) and 3 weeks of 5 mg enalapril once daily, 217 patients were randomized to 6 weeks of treatment with either a low-dose combination therapy (5 mg enalapril + 5 mg felodipine ER once daily, Lexxel, Astra Merck, Inc.), or a higher dose of monotherapy (10 mg enalapril once daily, Vasotec, Merck & Co., Inc.). The group randomized to the combination had significantly greater reductions in sitting systolic/diastolic blood pressure (BP)--14.2/10.6 mm Hg compared with baseline versus 9.6/7.4 mm Hg (P < .05/.01)--as well as a greater percentage of patients having achieved either diastolic BP < 90 mm Hg or a decline of at least 10 mm Hg (responders), 59% v 41% (P < .01). When patients originally taking 10 mg enalapril were crossed over to the combination therapy for a further 6 weeks, there was a further BP reduction and increase in response rate, with loss of significant differences compared with those treated continuously with the combination for the entire 12 weeks. The greater BP-lowering efficacy of the combination was independent of age, gender, and race. There were no significant differences in tolerability between the regimens. These data support the hypothesis that in patients who do not achieve goal BP reduction with a low dose of an antihypertensive agent, a combination of two drugs with complementary mechanisms of action is more effective than increasing the dose of the first agent.

Differential burst firing modes in neurons of the mammalian visual cortex in vitro.

The firing patterns of visual cortical neurons were studied by intracellular recording in in vitro guinea pig brain slices. On depolarization 57% of the cells exhibited tonic firing of action potentials while the remaining cells (43%) had a phasic component in their response. Phasic cells exhibited a large diversity in their burst characteristics as well as in the burst dependence on the membrane potential. Ionic conductances underlying burst generation appeared to be also diverse, thus bursting neurons in the visual cortex cannot be grouped in a single, homogeneous population.

NMDA-glutamate receptors regulate phosphorylation of dendritic cytoskeletal proteins in the hippocampus.

Most forms of synaptic potentiation need the activation of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors which generate changes in dendritic morphology of postsynaptic neurons. Since microtubule proteins have an essential role in dendritic morphology, they may be involved and regulated during the modifications of dendritic morphology associated with synaptic potentiation. The phosphorylation of the microtubule-associated proteins (MAPs) has been analyzed in situ after activation or blockade of NMDA-glutamate receptors in hippocampal slices. The phosphorylation of MAP1B and MAP2 has been studied by using several antibodies raised against phosphorylation-sensitive epitopes. Whereas antibodies 125 and 305 recognize phosphorylated epitopes on MAP1B and MAP2, respectively, Ab 842 recognizes a phosphorylatable sequence on MAP1B only when it is dephosphorylated. NMDA treatment decreased the phosphorylation state of the epitope recognized by the antibody 305 on MAP2 and caused a slight dephosphorylation of MAP1B sequences recognized by Ab 125 and 842. Moreover, exposure to APV (an antagonist of NMDA-glutamate receptors) counteracted the effect of NMDA and induced an increase in the phosphorylation state of these sequences in MAP2. Since phosphorylation regulates the interaction of MAPs with cytoskeleton, the results suggest that the modulation of the phosphorylated state of MAP2 by NMDA-glutamate receptors may be implicated in dendritic plasticity.

Evaluation of indapamide 1.25 mg once daily in elderly patients with mild to moderate hypertension.

The objective of this study was to evaluate the safety and efficacy of indapamide 1.25 mg once daily as monotherapy in elderly patients (65 years and older) with mild to moderate essential hypertension. Two hundred and seventy-nine (279) elderly patients were enrolled in a washout period, during which patients received single-blind placebo for 4 weeks. Patients demonstrating supine diastolic pressures between 95 mm Hg and 114 mm Hg at the end of the 4-week placebo washout period were entered into the 8-week double-blind treatment period. Two hundred and four (204) patients qualified for the study and were randomized to the double-blind treatment; 103 patients received indapamide 1.25 mg and 101 patients received placebo for 8 weeks. Overall, 177 patients (92 indapamide and 85 placebo) completed the study. The primary efficacy criterion was the mean change in supine diastolic blood pressure (DBP) from double-blind baseline to the end of 8 weeks of therapy. By week 8 of the double-blind treatment period, indapamide 1.25 mg produced a statistically significant (P = 0.0037) decrease in supine DBP of 8.2 mm Hg compared to a decrease of 5.3 mm Hg produced in the placebo group. Additionally, indapamide 1.25 mg was statistically (P = 0.0028) more effective than placebo in reducing supine systolic BP (SBP) (-10.1 vs -4.2 mm Hg). The incidence of drug-related adverse events during the double-blind treatment period was similar between the two treatment groups. A low dose of indapamide, 1.25 mg, given once daily for 8 weeks was effective as monotherapy with respect to BP reduction in an elderly population with mild to moderate hypertension. Indapamide 1.25 mg was safe and generally well tolerated in this elderly patient population.

Estimation of arsenic bioaccessibility in edible seaweed by an in vitro digestion method.

The aim of this study was to examine the bioaccessibility (maximum soluble concentration in gastrointestinal medium) of total (AsT) and inorganic (AsI) arsenic contents and the effect on them of cooking edible seaweed, a food of great interest because of its high As content. An in vitro gastrointestinal digestion (pepsin, pH 2, and pancreatin-bile extract, pH 7) was applied to obtain the mineral soluble fraction of three seaweeds (Hizikia fusiforme, Porphyra sp., and Enteromorpha sp.). AsT was determined by dry-ashing flow injection hydride generation atomic absorption spectrometry. AsI was determined by acid digestion, solvent extraction, and flow injection hydride generation atomic absorption spectrometry. The bioaccessibility of AsI increased significantly after cooking, attaining 73% in Porphyra sp. and 88% in H. fusiforme. For cooked H. fusiforme, the AsI attained in the bioaccessible fraction was 26 microg g(-1) seaweed, a concentration that is a warning of the toxicological risk of this food.

Kinetic study of transformations of arsenic species during heat treatment.

The combination of temperatures and pH levels applied in domestic or industrial cooking and in the sterilization of seafood might cause the transformation of certain species of arsenic into other more toxic species, which could pose a risk to the consumer. To clarify the effect of the temperatures traditionally used in cooking or sterilization on the stability of the various species of arsenic, a kinetic study was carried out, using standards of arsenobetaine (AB), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), trimethylarsine oxide (TMAO), tetramethylarsonium ion (TMA(+)), and arsenocholine (AC) heated at different temperatures (85--190 degrees C) and for different treatment times. Various pH levels (4.5, 5.5, 6.5, and 8.0) were applied during the heating process. The results obtained indicated that there were no transformations of arsenic species after temperature treatments up to 120 degrees C. However, when temperatures between 150 and 190 degrees C were used, a partial decomposition of AB was achieved, producing TMAO at 150 degrees C and TMAO and TMA(+) at temperatures of 160 degrees C or above, in proportions that varied according to the temperature and duration of the heat treatment.

Effect of cooking temperatures on chemical changes in species of organic arsenic in seafood.

The concentrations of arsenobetaine (AB), tetramethylarsonium ion (TMA(+)), and trimethylarsine oxide (TMAO) were determined in samples of sole, dory, hake, and sardine, raw and after being subjected to cooking processes--baking, frying, and grilling--at various temperatures. In all cases, the temperature attained inside the product during the cooking process was measured. The arsenic species extracted from the samples with methanol/water were separated by means of a column switching technique between a PRP-X100 column and a PRP-X200 column. AB was detected by hydride generation atomic absorption spectrometry, whereas TMA(+) and TMAO were detected by hydride generation atomic fluorescence spectrometry. The results obtained showed that, in all of the types of seafood studied, TMA(+) appeared after cooking, possibly because heating facilitates decarboxylation of AB to TMA(+).

Arsenic in cooked seafood products: study on the effect of cooking on total and inorganic arsenic contents.

Total and inorganic arsenic contents were analyzed in cooked seafood products consumed in Spain during the period July 1997-June 1998: hake, meagrim, small hake, anchovy, Atlantic horse mackerel, sardine, bivalves, crustaceans, squid, and salted cod. Various cooking treatments were used (grilling, roasting, baking, stewing, boiling, steaming, and microwaving). The results obtained were compared statistically with those found previously in the same products raw, and they showed that after cooking there was a significant increase in the concentration of total arsenic for salted cod and bivalves, and in the concentration of inorganic arsenic for bivalves and squid. The mean content of inorganic arsenic was significantly higher in bivalves than in any other type of seafood. For the Spanish population, the mean intake of total arsenic estimated on the basis of the results obtained in this study is 245 microg/day. The intake of inorganic arsenic (2.3 microg/day) represents 1.7% of the World Health Organization provisional tolerable weekly intake (PTWI), leaving an ample safety margin for this population, which has a very high consumption of seafood.

Heavy metal, total arsenic, and inorganic arsenic contents of algae food products.

The total arsenic, inorganic arsenic, lead, cadmium, and mercury contents of 18 algae food products currently on sale in Spain were determined. The suitability of the analytical methodologies for this type of matrix was confirmed by evaluating their analytical characteristics. The concentration ranges found for each contaminant, expressed in milligrams per kilogram of dry weight, were as follows: total arsenic, 2.3-141; inorganic arsenic, 0.15-88; lead, < 0.05-1.33; cadmium, 0.03-1.9; and mercury, 0.004-0.04. There is currently no legislation in Spain regarding contaminants in algae food products, but some of the samples analyzed revealed Cd and inorganic As levels higher than those permitted by legislation in other countries. Given the high concentrations of inorganic As found in Hizikia fusiforme, a daily consumption of 1.7 g of the product would reach the Provisional Tolerable Weekly Intake recommended by the WHO for an average body weight of 68 kg. A more comprehensive study of the contents and toxicological implications of the inorganic As present in the algae food products currently sold in Spain may be necessary, which might then be the basis for the introduction of specific sales restrictions.