Retinopatía viteliforme asociada a carcinoma de mama / Vitelliform retinopathy associated with breast cancer

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Queratitis neurotrófica posciclofotocoagulación transescleral con láser diodo / Neurotrophic keratitis after transscleral diode laser cyclophotocoagulation

OBJETIVO: Estudiar la relación existente entre el tratamiento con ciclofotocoagulación transescleral con láser de diodo y el desarrollo de queratitis neurotróficas por lesión de la inervación sensitiva corneal. MÉTODOS: Se han estudiado 5 ojos de 5 pacientes que fueron tratados con ciclofotocoagulación transescleral con láser de diodo y al poco tiempo desarrollaron úlceras neurotróficas. Se han recogido las diferentes características personales de los pacientes, incluyendo refracción y factores de riesgo de hipoestesia corneal, así como los parámetros de láser empleados en el tratamiento. RESULTADOS: Se comprobó que los 5 pacientes presentaban factores predisponentes de hipoestesia corneal previos a la cirugía (uso de betabloqueantes tópicos crónicos, cirugías corneales, diabetes mellitus o distrofias corneales). Sin embargo, ninguno había desarrollado queratitis neurotróficas hasta el momento de la ciclofotocoagulación. Se evidenció, además, que 4 de ellos eran altos miopes y que todos ellos fueron tratados con parámetros elevados de láser (2.880 mW por 3 s, en una superficie de 275° de media), y se desencadenaron úlceras neurotróficas entre los 10 y los 35 días después de la cirugía. CONCLUSIONES: La queratopatía neurotrófica es una complicación poco frecuente que puede aparecer tras la ciclofotocoagulación transescleral con láser de diodo, debido a la lesión secundaria de los nervios ciliares largos. La aparición de esta se puede ver favorecida por la existencia de factores de riesgo previos, entre los que hay que incluir la alta miopía. Es crucial respetar los parámetros de tratamiento recomendados, para evitar la aparición de esta dolencia

OBJECTIVE: To study the relationship between treatment with diode laser transscleral cyclophotocoagulation and development a neurotrophic keratitis due to the damage of the sensitive corneal innervation. METHODS: A study was conducted on 5 eyes of 5 patients who were treated with diode laser transscleral cyclophotocoagulation and soon developed neurotrophic ulcers. Personal characteristics of the patients were collected, as well as refraction and risk factors for corneal hypoesthesia, and the parameters of the laser used in the surgery. RESULTS: It was found that the 5 patients had predisposing factors of corneal hypoesthesia prior to surgery (chronic use of topical beta blockers, surgery with corneal incisions, diabetes mellitus, or corneal dystrophies); however none had developed neurotrophic keratitis until the cyclophotocoagulation was performed. It also showed that 4 of them were highly myopic, and they all were treated with high laser parameters (with an average of 2880 mW for 3 s at an average surface of 275°), triggering neurotrophic ulcers between 10 and 35 days after surgery. CONCLUSION: Neurotrophic keratitis is a rare complication that can occur after diode laser transscleral cyclophotocoagulation, secondary to the damage of the long ciliary nerves. The emergence of this disorder can be triggered by the existence of previous risk factors, including high myopia, thus it is important to respect the recommended treatment parameters to prevent the development of this disorder

Neurotrophic keratitis after transscleral diode laser cyclophotocoagulation. / Queratitis neurotrófica posciclofotocoagulación transescleral con láser diodo.

OBJECTIVE: To study the relationship between treatment with diode laser transscleral cyclophotocoagulation and development a neurotrophic keratitis due to the damage of the sensitive corneal innervation. METHODS: A study was conducted on 5 eyes of 5 patients who were treated with diode laser transscleral cyclophotocoagulation and soon developed neurotrophic ulcers. Personal characteristics of the patients were collected, as well as refraction and risk factors for corneal hypoesthesia, and the parameters of the laser used in the surgery. RESULTS: It was found that the 5 patients had predisposing factors of corneal hypoesthesia prior to surgery (chronic use of topical beta blockers, surgery with corneal incisions, diabetes mellitus, or corneal dystrophies); however none had developed neurotrophic keratitis until the cyclophotocoagulation was performed. It also showed that 4 of them were highly myopic, and they all were treated with high laser parameters (with an average of 2880 mW for 3s at an average surface of 275°), triggering neurotrophic ulcers between 10 and 35 days after surgery. CONCLUSION: Neurotrophic keratitis is a rare complication that can occur after diode laser transscleral cyclophotocoagulation, secondary to the damage of the long ciliary nerves. The emergence of this disorder can be triggered by the existence of previous risk factors, including high myopia, thus it is important to respect the recommended treatment parameters to prevent the development of this disorder.

Acetaldehyde removal using an atmospheric non-thermal plasma combined with a packed bed: role of the adsorption process.

This work is an attempt in order to help towards understanding the influence of the adsorption process on the removal of a VOC (acetaldehyde, CH3CHO) using cyclic non thermal plasma (NTP) combined with a packed-bed of a catalyst support, α-Al2O3. In the first part, the results obtained by placing the saturated alumina pellets inside the plasma discharge zone are discussed, in terms of acetaldehyde removal, CO and CO2 production. In the second part, adsorption of CH3CHO, CO, CO2 and O3 was carried out, from single and multicomponent mixtures of the different compounds. The results showed that (i) the adsorption capacities followed the order CH3CHO≫ CO2>CO; (ii) O3 was decomposed on the alumina surface; (iii) CO oxidation occurred on the surface when O3 was present. In the third part, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to follow the alumina surface during acetaldehyde adsorption. DRIFTS measurements demonstrated that besides the bands of molecularly adsorbed acetaldehyde, several absorptions appeared on the spectra showing the intermediate surface transformation of acetaldehyde already at 300K. Finally, the relationship between the adsorption results and the NTP combined with a packed-bed process is discussed.

The effect of biomaterials and antifungals on biofilm formation by Candida species: a review.

Candida albicans, C. glabrata, C. parapsilosis, and C. tropicalis are able to form biofilms on virtually any biomaterial implanted in a human host. Biofilms are a primary cause of mortality in immunocompromised and hospitalized patients, as they cause recurrent and invasive candidiasis, which is difficult to eradicate. This is due to the fact that the biofilm cells show high resistance to antifungal treatments and the host defense mechanisms, and exhibit an excellent ability to adhere to biomaterials. Elucidation of the mechanisms of antifungal resistance in Candida biofilms is of unquestionable importance; therefore, this review analyzes both the chemical composition of biomaterials used to fabricate the medical devices, as well as the Candida genes and proteins that confer drug resistance.

Development of a patient simulator for teaching and evaluation of the basic cardio-pulmonary reanimation protocol.

Providing appropriate cardio-pulmonary reanimation after cardio-pulmonary arrest is paramount for survival. An effective and low-cost approach to learn and practice the cardio-pulmonary reanimation is through a computerized life-size patient simulator. The present work describes the development of a patient simulator for the Centre of Education and Certification of Medical Aptitudes (CECAM) from the UNAM's Faculty of Medicine. This patient simulator has many new and innovative features, such real-time feedback to the medical student, which improves the whole teaching/learning experience.

BME education program and research activities at the National Autonomous University of Mexico (UNAM).

Biomedical engineering at the Universidad Nacional Autónoma de Mexico (UNAM - National Autonomous University of Mexico) has been developing slowly compared to other local universities. A BME-closing module was established as an elective one for the bachelors of electronic and computer engineering degrees and it has been offered recently. This approach enables the students to apply the principles of physics and engineering in a biomedical context. The popularity of the BME-closing module is growing and more students are opting for this module. This paper presents the BME activities at the UNAM and the experience of the elective module.

Vasopressinergic network abnormalities potentiate conditioned anxious state of rats subjected to maternal hyperthyroidism.

We have previously reported that a mild maternal hyperthyroidism in rats impairs stress coping of adult offspring. To assess anxiogenesis in this rat model of stress over-reactivity, we used two behavioural tests for unconditional and conditional anxious states: elevated plus maze test (EPM) and Vogel conflict test (VCT). In the latter one, arginine vasopressin (AVP) release was enhanced due to osmotic stress. With the EPM test no differences were observed between maternal hyperthyroid rats (MH) and controls. However, with the VCT, the MH showed increased anxiety-like behaviour. This behavioural difference was abolished by diazepam. Plasma AVP concentration curve as a function of water deprivation (WD) time showed a marked increase, reaching its maximal levels within half the time of controls and another significant difference after VCT. A general increase in Fos expression in hypothalamic supraoptic and paraventricular nuclei (PVN) was observed during WD and after VCT. There was also a significant increase of AVP immunoreactivity in anterior hypothalamic area. A large number of Herring bodies were observed in the AVP containing fibres of MH hypothalamic-neurohypophysial system. Numerous reciprocal synaptic connections between AVP and corticotropin releasing factor containing neurons in MH ventromedial PVN were observed by electron microscopy. These results suggest that a mild maternal hyperthyroidism could induce an aberrant organization in offspring's hypothalamic stress related regions which could mediate the enhanced anxiety seen in this animal model.

Composite fibrous biomaterials for tissue engineering obtained using a supercritical CO2 antisolvent process.

Several techniques have been proposed for producing porous structures or scaffolds for tissue engineering but, as yet, with no optimal solution. With regard to this topic, this paper focuses on the preparation of biocompatible nanometric filler-polymer composites organized in a network of fibers. Titanium dioxide (TiO2) or hydroxyapatite (HAP) nanopowders as the guest particles and poly(lactic acid) (L-PLA) or the blend poly(methylmethacrylate)/poly(epsilon-caprolactone) (PMMA/PCL) as the polymer carrier were selected as model systems for this purpose. A supercritical antisolvent technique was used to produce the composites. In the process developed, the non-soluble particulate filler was suspended in a polymer solution, and both components were sprayed simultaneously into supercritical carbon dioxide (scCO2). Using this technique, polymeric matrices were loaded with approximately 10-20 wt.% of inorganic phase distributed throughout the composite. Two different hybrid materials were prepared: a PMMA/PCL+TiO2 system where either fibers or microparticles were prepared by varying the molecular weight of the used PMMA; and fibers in the case of L-PLA+HAP system. After further post-processing in a three-dimensional network, these nanofibers can potentially be used as scaffolds for tissue engineering.

Continuous monitoring of upper-limb activity in a free-living environment: a validation study.

Monitoring upper-limb activity in a free-living environment is important for the evaluation of rehabilitation. This study is a validation of the Strathclyde Upper-Limb Activity Monitor (SULAM) which records the vertical movement and position of each wrist, and assesses bimanual movement. Agreement between the SULAM and two independent video observers was assessed using interclass correlation coefficients (ICC) and the Bland and Altman method. Concurrent validity was very good for movement of each upper-limb (ICC > 0.9), and good for the vertical position of the wrist (ICC > 0.8 for wrist positions below the shoulder, ICC > 0.6 otherwise). The ICC was good (>0.8) for bimanual movement, however the SULAM systematically underreported this by approximately 15%. The SULAM could be a useful tool to assess upper-limb activity of clinical populations in their usual environment.

Measuring continuous real-world upper-limb activity.

The Strathclyde Upper-Limb Activity Monitor (SULAM) was used to assess real-world upper-limb activity. The SULAM consists of an electro-hydraulic activity-sensor which measures the vertical displacement of the wrist in relation to the shoulder. The aims of this study were to obtain a profile of upper-limb activity in two different populations (able-bodied participants and stroke patients) Ten able-bodied volunteers and ten stroke patients-wore the SULAM while performing their everyday activities. The outcome measures were movement time, its distribution in five vertical ranges, bimanual and unimanual movement time. There was a difference in the use of both upper-limbs for both groups, favouring the dominant/unaffected arm. This difference was only in two of the five ranges (chest to shoulder and shoulder to head for able-bodied participants; waist to chest and chest to shoulder for stroke patients). Bimanual movement was greater than unimanual movement for able-bodied participants whereas unimanual movement was greater than bimanual movement for stroke patients.

Manipulations during forced wakefulness have differential impact on sleep architecture, EEG power spectrum, and Fos induction.

We propose a hypothesis suggesting that the most prominent experiences occurring during wakefulness activate specific clusters of neurons related to such experiences. These neurons could possibly then evoke the release of various types of sleep-inducing molecules, thereby causing different patterns of sleep architecture. In this study, we therefore sought to determine whether manipulations of behavior during wakefulness, such as forced wakefulness induced by gentle handling, forced wakefulness associated with a stressful condition such as immobilization, or forced wakefulness associated with excess intake of palatable food, could result in a variation of Fos immunoreactivity in selective brain structures and could also result in different sleep and EEG power density patterns. The results showed that the sleep-wake cycle of rats after all the experimental manipulations was different not only with respect to the control group but also among themselves. Additionally, power spectrum analysis showed an increase of 0.25-4.0 Hz in all experimental manipulations, whereas the 4.25-8.0 Hz increase occurred only in the situation of forced wakefulness plus stress. The Fos induction showed activation of cell clusters in cortical areas and telencephalic centers, in several hypothalamic nuclei, in monoaminergic cell groups, and in brain stem nuclei. The density of Fos-immunoreactive neurons varied in relation to the different paradigms of forced wakefulness. These results suggest that activation of cell clusters in the brain are related to the type of manipulation imposed on the rat during wakefulness and that such variation in cell activation prior to sleep may be associated with sleep architecture and EEG power.

Extremely low frequency magnetic fields promote neurite varicosity formation and cell excitability in cultured rat chromaffin cells.

We report the use of an extremely low frequency magnetic field (ELF-MF, 60 Hz, 10 Grms) to stimulate cultured chromaffin cells to determine the possible changes that may occur in their electrical properties. The results showed that ELF-MF not only facilitated neurite outgrowth, but also formation of neurite varicosity with high concentration of catecholamines. This report also shows for the first time that a greater number of cultured chromaffin cells differentiated by ELF-MF have spontaneous extracellular electrical activity and that their firing frequency is higher than that seen in non-stimulated cells.

Temporal variations of adenosine metabolism in human blood.

Eight diurnally active (06:00-23:00 h) subjects were adapted for 2 days to the room conditions where the experiments were performed. Blood sampling for adenosine metabolites and metabolizing enzymes was done hourly during the activity span and every 30 min during sleep. The results showed that adenosine and its catabolites (inosine, hypoxanthine, and uric acid), adenosine synthesizing (S-adenosylhomocysteine hydrolase and 5'-nucleotidase), degrading (adenosine deaminase) and nucleotide-forming (adenosine kinase) enzymes as well as adenine nucleotides (AMP, ADP, and ATP) undergo statistically significant fluctuations (ANOVA) during the 24 h. However, energy charge was invariable. Glucose and lactate chronograms were determined as metabolic indicators. The same data analyzed by the chi-square periodogram and Fourier series indicated ultradian oscillatory periods for all the metabolites and enzymatic activities determined, and 24-h oscillatory components for inosine, hypoxanthine, adenine nucleotides, glucose, and the activities of SAH-hydrolase, 5'-nucleotidase, and adenosine kinase. The single cosinor method showed significant oscillatory components exclusively for lactate. As a whole, these results suggest that adenosine metabolism may play a role as a biological oscillator coordinating and/or modulating the energy homeostasis and physiological status of erythrocytes in vivo and could be an important factor in the distribution of purine rings for the rest of the organism.

Splitting of locomotor circadian rhythmicity in hamsters is facilitated by pinealectomy.

The role of the pineal gland in the mammalian circadian system has not been well established, in contrast to a fair number of reports indicating pharmacological effects of melatonin in the circadian organization. In order to establish the effects of pinealectomy on the time course of splitting of circadian rhythmicity, the wheel running locomotor activity was continuously recorded in golden hamsters under light-dark conditions or constant light. The analysis of transients from the actograms shows that removal of the pineal gland induces a reduction in the latency and an increase in the duration of transients before the splitting occurs. The power spectral analysis from selected segments of the data shows that concomitant to the development of the splitting there is an increase in the power of ultradian components. In pinealectomized animals the changes in the power spectrum occurs at least 30 days before that in the control animals. These observations suggest that pineal gland could be involved in the coupling mechanism among the different oscillators of the rodent circadian system. Furthermore, since the light intensity used in this study is enough to completely suppress the melatonin synthesis from the pineal, the present results suggest that a signal from the pineal other than melatonin is involved in the process.