Modelo animal de ectasia corneal en conejo mediante inyección intraestromal de colagenasa tipo ii / Animal model of corneal ectasia in rabbits by intrastromal injection of type II collagenase

Introducción La colagenasa ii ha sido utilizada para inducir queratocono experimental en modelos animales. Sin embargo, no ha sido estudiado su efecto cuando se administra por inyección intraestromal, por lo que el propósito de este estudio fue estudiar los efectos de la inyección intraestromal de colagenasa ii sobre la superficie corneal y la morfología de la córnea. Método Se trabajó con 6 conejos Nueva Zelanda, se administró colagenasa ii por inyección intraestromal (5μL de 2,5mg/mL) en los ojos derechos y solución salina balanceada en los ojos izquierdos. Se realizaron queratometrías para evaluar la alteración de la curvatura, también al séptimo día se obtuvieron las córneas y se realizó tinción hematoxilina-eosina para examinar los cambios morfológicos. Asimismo, se investigaron los cambios en la expresión de colágeno tipo i por tinción rojo sirio y PCR semicuantitativa. Resultados K1, K2 y Km presentaron diferencias en los promedios con cambios estadísticamente significativos. Los cambios morfológicos que se demostraron fueron degradación y disposición irregular del estroma corneal, incremento en la densidad celular de queratocitos y ligera infiltración celular. Finalmente se demostró que hay mayor expresión de fibras de colágeno tipo i en el grupo experimental a diferencia de los controles y el grosor de las fibras también aumentó por acción de la colagenasa ii; sin embargo, en cuestión génica no hubo cambios en la expresión de colágeno tipo i a nivel molecular entre el grupo control y experimental. Conclusiones La colagenasa ii administrada por inyección intraestromal es capaz de inducir cambios en la superficie corneal y el estroma, pudiendo simular un modelo de queratocono (AU)

Introduction Collagenase II has been used to induce experimental keratoconus in animal models. However, its effect when administered by intrastromal injection has not been studied, so the purpose of this study was to study the effects of intrastromal injection of collagenase II on corneal surface and corneal morphology. Method Six New Zealand rabbits were used, collagenase II was administered by intrastromal injection (5μL of 2.5mg/mL) in the right eyes and balanced salt solution in the left eyes. Keratometry was performed to evaluate curvature alteration, also at day 7 corneas were obtained and hematoxylin–eosin staining was performed to examine morphologic changes. Likewise, changes in type I collagen expression were investigated by Sirius Red staining and semi-quantitative PCR. Results K1, K2, and Km presented differences in the means with statistically significant changes. The morphological changes that were demonstrated were degradation and irregular arrangement of the corneal stroma, increase in the cellular density of keratocytes and slight cellular infiltration. Finally, it was demonstrated that there is greater expression of type I collagen fibers in the experimental group as opposed to the controls and the thickness of the fibers also increased due to the action of collagenase II, however, in terms of genetics there were no changes in the expression of type I collagen at molecular level between the control and experimental groups. Conclusions Collagenase II administered by intrastromal injection is able to induce changes in the corneal surface and stroma, being able to simulate a model of keratoconus (AU)

Animal model of corneal ectasia in rabbits by intrastromal injection of type II collagenase.

INTRODUCTION: Collagenase II has been used to induce experimental keratoconus in animal models. However, its effect when administered by intrastromal injection has not been studied, so the purpose of this study was to study the effects of intrastromal injection of collagenase II on corneal surface and corneal morphology. METHODS: Six New Zealand rabbits were used, collagenase II was administered by intrastromal injection (5µL of 2.5mg/mL) in the right eyes and balanced salt solution in the left eyes. Keratometry was performed to evaluate curvature alteration, also at day 7 corneas were obtained and Hematoxylin-Eosin staining was performed to examine morphologic changes. Likewise, changes in type I collagen expression were investigated by Sirius Red staining and semiquantitative PCR. RESULTS: K1, K2 and Km presented differences in the means with statistically significant changes. The morphological changes that were demonstrated were degradation and irregular arrangement of the corneal stroma, increase in the cellular density of keratocytes and slight cellular infiltration. Finally, it was demonstrated that there is greater expression of type I collagen fibers in the experimental group as opposed to the controls and the thickness of the fibers also increased due to the action of collagenase II, however, in terms of genetics there were no changes in the expression of type I collagen at molecular level between the control and experimental groups. CONCLUSIONS: Collagenase II administered by intrastromal injection is able to induce changes in the corneal surface and stroma, being able to simulate a model of keratoconus.

Recidiva de endometriosis en pared abdominal. Reporte de caso / Recurrence of endometriosis in the abdominal wall. A case report

Introducción: La endometriosis de pared abdominal es una patología infrecuente, que generalmente se desarrolla en una cicatriz quirúrgica posterior a un procedimiento ginecológico y/o ginecoobstétrico. Caso clínico: Mujer de 29 años, G3C2A1V2, antecedentes de esterilización quirúrgica, quien un año después a su última cesárea presenta cuadro de dolor pélvico crónico asociado a ciclo menstrual, que se acompañaba de sangrado menstrual abundante y sensación de masa en hipogastrio. Con diagnóstico de endometriosis en pared abdominal, razón por la cual realizan resección. Sin embargo, tras un año posterior al procedimiento recidiva de endometriosis en pared abdominal, en esta ocasión, con requerimiento de resección amplia de fascia, colocación de malla y cierre por planos. Conclusiones: La endometriosis de pared abdominal es de difícil diagnóstico, ya que comparativamente es una entidad infrecuente, que no ha recibido una adecuada atención. Es importante sospecharla en mujeres con dolor abdominal cíclico y presencia de masa en la pared abdominal, adicionalmente con la utilización de imágenes diagnósticas. La resección quirúrgica es el tratamiento ideal, sin embargo, es importante recalcar la importancia de una resección amplia de márgenes para evitar recidivas. Adicionalmente el cierre por planos que evite defectos en la pared abdominal.(AU)

Introduction: Abdominal wall endometriosis is an uncommon pathology, which usually develops in a surgical scar following a gynaecological and/or gynaecological-obstetric procedure. Case study: Female, 29 years old, G3C2A1V2, history of surgical sterilization. One year after her last cesarean section, she presented with chronic pelvic pain associated with the menstrual cycle, accompanied by heavy menstrual bleeding and a sensation of a mass in the hypogastrium. She was diagnosed with endometriosis in the abdominal wall, and resection was performed. However, one year after the procedure, the endometriosis in the abdominal wall recurred, this time requiring wide fascia resection, mesh placement and layered closure. Conclusions: Abdominal wall endometriosis is difficult to diagnose, since it is a comparatively infrequent entity, which has not received adequate attention. It is important to suspect it in women with cyclic abdominal pain and the presence of a mass in the abdominal wall, in addition to the use of diagnostic imaging. Surgical resection is the ideal treatment, however, it is important to emphasize the importance of a wide margin resection to avoid recurrence. Layered closure is also important to avoid defects in the abdominal wall.(AU)

Advances in the assessment of self-determination: internal structure of a scale for people with intellectual disabilities aged 11 to 40.

BACKGROUND: Advances in theoretical frameworks of self-determination require the development of new assessment instruments. This study examines the dimensional structure of a self-determination scale and analyses the factorial invariance of its measurement across age and gender. METHOD: The AUTODDIS Scale was used to assess the self-determination of 541 people with intellectual disabilities aged from 11 to 40. RESULTS: Different models (correlational and hierarchical structures) of the scale were tested. The correlational model obtained from the exploratory structural equation model approach provided the best fit for the data. The results also supported measurement invariance across youths (aged 11 to 21 years) and adults (aged 21 to 40 years) and across genders. CONCLUSIONS: This study contributes to international research on self-determination and the development of assessment tools in this field, offering a better understanding of this multifaceted and complex construct. The results provide construct validity evidence regarding a new measurement tool tested across people aged 11 to 40, using information from third parties. However, further research is needed to explore the best ways to understand and assess the different factors related to self-determination.

Uso de Biomateriales Funcionalizados con Moléculas Bioactivas en la Ingeniería Biomédica / Use of Functionalized Biomaterials with Bioactive molecules in Biomedical Engineering

Resumen El artículo expone la importancia del uso de moléculas bioactivas para la funcionalización de biomateriales. Por esta razón, se realizó una revisión de investigaciones actuales y relevantes en diversos buscadores de datos, incluyendo los diferentes tipos de materiales y moléculas bioactivas utilizadas para elaborar biomateriales funcionalizados, con énfasis en los procesos y sus propiedades. Se encontró que el proceso de funcionalización o modificación de la superficie expande el camino para adaptar al biomaterial de acuerdo al entorno fisiológico de las células vivas. De esta manera, el proceso mejora la estructura y las funciones de los tejidos y órganos diseñados. Existen una variedad de métodos y moléculas bioactivas disponibles para la funcionalización de los biomateriales, las cuales dependen de la manera en las que las células o tejidos se regeneran. Entre los diferentes materiales para la fabricación de biomateriales, las biomoléculas como las proteínas, lípidos, carbohidratos, entre otros, son una de las opciones más utilizadas debido a la similitud de estas con los sistemas biológicos del cuerpo humano. Finalmente, el artículo también integra algunas de las más prometedoras aplicaciones de moléculas bioactivas incorporadas a los biomateriales.

Abstract The paper exposes the importance of the use of bioactive molecules for the functionalization of biomaterials. For this reason, a review of current and relevant research was carried out in various data searchers, including the different types of bioactive materials and molecules used to elaborate functionalized biomaterials, with emphasis on the processes and their properties. It was found that the process of functionalization or modification of the surface expands the path to adapt the biomaterial according to the physiological environment of living cells. This process improves the structure and functions of the designed tissues and organs. There are a variety of methods and bioactive molecules available for the functionalization of biomaterials, depending on the way in which the cells or tissues are regenerated. Among the different materials for the manufacture of biomaterials, biomolecules such as proteins, lipids, carbohydrates, among others, are one of the most used options due to the similarity of these with the biological systems of the human body. Finally, the paper also integrates some of the most promising applications of bioactive molecules incorporated into biomaterials.

Diversity improves performance and outcomes.

BACKGROUND: Research on the effects of increasing workplace diversity has grown substantially. Unfortunately, little is focused on the healthcare industry, leaving organizations to make decisions based on conflicting findings regarding the association of diversity with quality and financial outcomes. To help improve the evidence-based research, this umbrella review summarizes diversity research specific to healthcare. We also look at studies focused on professional skills relevant to healthcare. The goal is to assess the association between diversity, innovation, patient health outcomes, and financial performance. METHODS: Medical and business research indices were searched for diversity studies published since 1999. Only meta-analyses and large-scale studies relating diversity to a financial or quality outcome were included. The research also had to include the healthcare industry or involve a related skill, such as innovation, communication and risk assessment. RESULTS: Most of the sixteen reviews matching inclusion criteria demonstrated positive associations between diversity, quality and financial performance. Healthcare studies showed patients generally fare better when care was provided by more diverse teams. Professional skills-focused studies generally find improvements to innovation, team communications and improved risk assessment. Financial performance also improved with increased diversity. A diversity-friendly environment was often identified as a key to avoiding frictions that come with change. CONCLUSIONS: Diversity can help organizations improve both patient care quality and financial results. Return on investments in diversity can be maximized when guided deliberately by existing evidence. Future studies set in the healthcare industry, will help leaders better estimate diversity-related benefits in the context of improved health outcomes, productivity and revenue streams, as well as the most efficient paths to achieve these goals.

[Arterial Hypertension register in private clinics in Venezuela: RHAVEN Study]. / Registro de Hipertensión Arterial en consultas privadas en Venezuela: Estudio RHAVEN.

INTRODUCTION: In Venezuela, no large studies have been conducted to determine the level of control of hypertension (HT). OBJECTIVE: The primary objective was to know the prevalence of controlled HT among hypertensive patients treated pharmacologically. MATERIALS AND METHODS: A cross-section study was conducted on patients 18years and older. RESULTS: A total of 4,320 patients were included. The prevalence of controlled hypertension was 52.6% (95%CI: 51.1-54.1%). The lack of control of HT was associated with diabetes (P<.001), hypertensive heart disease (P<.001), chronic kidney disease (P<.001), and peripheral arterial disease (P=.02). Non-compliance of treatment was also associated with uncontrolled HT (5.1% [117/2,274] in the controlled versus 43.2% [885/2,046] in the uncontrolled; (P<.001). CONCLUSION: The prevalence detected of controlled hypertension was 52.6%.

Implementación de un sistema de imagenología infrarroja para la detección vascular del antebrazo y mano / Implementation of an infrared imaging system for vascular detection in the forearm and hand

RESUMEN: En el área clínica son procedimientos comunes la venopunción, la colocación de catéteres, inyecciones intravenosas, etc. La visualización de las venas en algunas personas es compleja. En este trabajo se presenta el desarrollo de un sistema capaz de realzar la distribución de las venas en el antebrazo de una persona para, en un trabajo futuro, ayudar de forma no invasiva a localizar las venas en los procedimientos de venopunción. Para llevar a cabo el desempeño de esta tarea se utilizó una cámara web, a la cual se le ha extraído el filtro que impide el paso de luz infrarroja y es sustituido por otro que lo permite. Para mejorar la detección de las venas se le agregó a la cámara un arreglo de LEDs emisores de luz infrarroja (830nm). Las imágenes obtenidas fueron procesadas mediante la ecualización del histograma adaptable y clasificadas por dos métodos, el primero basado en el algoritmo Fuzzy C-Means, el segundo basado en un modelo probabilístico de tipo Bayes, técnicas del área de inteligencia artificial, presentadas como alternativa en el procesamiento de imágenes. Para la obtención de las imágenes se consideraron las regiones anteriores y exteriores del antebrazo izquierdo y derecho de cada sujeto generando una base de datos. Este sistema también tiene aplicación en la detección de venas varicosas debido a que se puede dar un seguimiento a la dilatación de las venas.

ABSTRACT: The venipuncture, the catheterization and intravenous (IV) injections are some of the common procedures in the clinical practice. The location of the veins may be complex in some patients. In this paper a system able to enhance the vein distribution in a patient's forearm in order to help, in future works, to locate the veins in a non-invasive way and accomplish the IV procedures, is described. To carry out this work a web cam was used, the filter that blocks out the infrared light has been removed and replaced for one who does not. To increase the vein detection an array of infrared LEDs (830 nm) was attached. The resulting images were processed using the adaptive histogram equalization and then classified by two methods, the first one based on the Fuzzy C-Means Algorithm, and the second based in a Bayesian probabilistic model. For the image acquisition, the anterior-exterior regions of the left and right forearm of each subject were considered to generate a data base. This system also has relevance in the detection of varicose veins since is able to monitor the vein dilatation.

Photosynthetic bacteria-based membrane bioreactor as post-treatment of an anaerobic membrane bioreactor effluent.

Anaerobic membrane bioreactors have attracted increasing interest in the field of wastewater treatment. However, significant amounts of organic matter, nitrogen and sulphide in the effluent may limit its reuse. A photosynthetic bacteria-based membrane bioreactor is proposed for the further treatment of this effluent. A pilot-scale unit was run outdoor for over 900h to assess the process performance at short hydraulic retention time. After an initial biomass development, simultaneous removal of soluble organic matter and nitrogen was achieved (65% and 39%, respectively). In addition, a significant concentration of sulphate was detected in the permeate, revealing an evident sulphide oxidation. Despite the accumulation of biopolymer clusters in the biological suspension, membrane fouling was effectively mitigated by air-aided backwashing, allowing a sustainable operation. Several strains of bacteria were identified including the photoheterotrophic bacteria Rhodopseudomonas sp. and the nitrifying and denitrifying bacteria Chryseobacterium sp.

Apósitos de polímeros naturales para regeneración de piel / Natural polymers aposites for skin regeneration

Resumen El presente artículo es una amplia revisión bibliográfica de algunos de los polímeros naturales más utilizados en la fabricación de apósitos para curación de heridas cutáneas y regeneración de piel en los últimos años. Asimismo, se presenta un análisis descriptivo de los polímeros de origen natural más estudiados en la ingeniería de tejidos, remarcando sus propiedades físicas, químicas y biológicas. Encontrando que las investigaciones más recientes se han centrado en la exploración de apósitos a partir de biopolímeros como una alternativa a los materiales sintéticos derivados del petróleo, debido a las propiedades que poseen, como una mayor biodegradabilidad, biocompatibilidad y sostenibilidad por ser obtenidos naturalmente. Sin embargo, aún no existe un apósito ideal que pueda ser aplicado de manera eficiente en todos los tipos de heridas; por lo que los investigadores se han enfocado en el desarrollo y la optimización de apósitos que satisfagan la mayoría de las necesidades para una etapa en particular de la herida.

Abstract This review includes the bio-polymers most used in recent years for the manufacturing of materials used as dressings in cutaneous wound healing and skin regeneration. Also, the natural polymers most studied in tissue engineering are mentioned, highlighting their physical, chemical and biological properties for skin regeneration and wound healing. Through an extensive review of the clinical and research uses different types of natural polymers were compared, as well as the results of chemical and biological tests carried out during experimental research performed internationally.

Operationalisation of quality of life for adults with severe disabilities.

BACKGROUND: The operationalisation of quality of life for people with more severe disabilities has been acknowledged in the published research for more than two decades. This study aims to contribute to our knowledge and understanding of the quality of life of adults with severe disabilities by developing a set of quality of life indicators appropriate to this population using a Delphi method and the eight-domain conceptual model proposed by Schalock & Verdugo (2002). METHOD: The participating panel in the Delphi method included 12 experts who evaluated each proposed item according to four criteria: suitability, importance, observability and sensitivity. Descriptive analyses were used to select the best items in each of the four rounds of this Delphi study, as well as examining the coefficients of concordance that were calculated for the final pool of items. RESULTS: The four rounds of the Delphi study resulted in a final pool of 118 items (91 that were considered valid in the first round plus 27 items proposed, reformulated or discussed in the following rounds). Importance and sensitivity were the criteria that received the highest and lowest ratings, respectively, but also the ones that had the highest and lowest mean coefficients of concordance. Experts showed the strongest agreement for items related to material well-being, while the weakest was found for items related to personal development. CONCLUSIONS: This study further contributes to our understanding of how to operationalise and measure quality of life in adults with severe disabilities. The item pool generated may prove helpful in the development of instruments for the measurement of quality of life-related outcomes in this population.

The concept of quality of life and its role in enhancing human rights in the field of intellectual disability.

BACKGROUND: The changed societal views of persons with disabilities are reflected in the 2006 United Nations Convention on the Rights of Persons with Disabilities. However, what is not specified in the Convention is how to operationalise and measure the Articles composing the Convention, and how to use that information to further enhance the human rights of persons with disabilities. METHOD: The authors analyse the relationships between eight core quality of life domains and the 34 Articles contained in the Convention. RESULTS: There is a close relationship between the core quality of life domains and the 34 Articles contained in the Convention. Furthermore, the current status of these Articles can be evaluated through the assessment of indicators associated with the eight core quality of life domains. CONCLUSIONS: Based on the assessment of these quality of life-related outcomes, three strategies can be used to enhance the human rights of persons with intellectual disability. These three are to employ person-centred planning, publish provider profiles and implement a system of support.

Effect of oxygen injection in a reclaimed wastewater pipeline on the microbiological quality of water.

In this work the influence of oxygen injection on the inactivation of microbiological indicators during reclaimed wastewater transportation was studied. Experiments were carried out in a completely filled gravity pipe (62 km long), at two different periods of the year and with three different oxygen doses (7, 15 and 30 mg L(-1)). Microbiological parameters studied were faecal coliforms, Escherichia coli, enterococci and somatic coliphages. As a consequence of the oxygen injection, a significant inactivation of the microbiological parameters was observed during the aerobic stretch of the pipe. Later, once the oxygen had been consumed, inactivation stopped and even a slight regrowth of the microbial population took place. Inactivations were within the range of 0.6-1.0 log10 units, in most cases. No significant differences between inactivations for the different microbiological parameters were found, except for the somatic coliphages. A relationship between the inactivation degree and oxygen dose and organic matter content was observed. The biofilm played an important role in the inactivation process. The injection of oxygen contributes to improving the microbiological quality of reclaimed wastewater during its transport by pipelines, helping to diminish the subsequent on-site disinfection requirements.

Reclaimed wastewater quality enhancement by oxygen injection during transportation.

In-sewer treatments have been studied in sewer systems, but few have been carried out on reclaimed wastewater systems. A study of oxygen injection has been performed in a completely filled gravity pipe, 0.6 m in diameter and 62 km long, in cast iron with concrete inside coating, which is part of the reclaimed wastewater reuse scheme of Tenerife (Spain). A high pressure oxygen injection system was installed at 16.0 km from pipe inlet and a constant dosage of 30 mg/L O(2) has been injected during six months, under three different operational modes (low COD, 63 mg/L; high COD, 91 mg/L; and partially nitrified water). Oxygen has been consumed in nitrification and organic matter reduction. Generally, nitrification is clearly favored instead of the organic matter oxidation. Nitrification occurs, in general, with nitrite accumulation due to the presence of free ammonia above 1 mg/L. Denitrification is in all cases incomplete due to a limitation of easily biodegradable organic matter content, inhibiting the appearance of anaerobic conditions and sulfide generation. A notable reduction of organic matter parameters is achieved (TSS below 10 mg/L), which is significantly higher than that observed under the ordinary transport conditions without oxygen. This leads to a final cost reduction, and the oxygen injection system helps water reuse managers to maintain a final good water quality in the case of a treatment plant malfunction.

Nitrogen transformation of reclaimed wastewater in a pipeline by oxygen injection.

A study of oxygen injection was performed in a completely filled gravity pipe, which is part of the South Tenerife reclaimed wastewater reuse scheme (Spain), in order to inhibit the appearance of anaerobic conditions by a nitrification-denitrification process. The pipe was 0.6 m in diameter and 62 km long and made of cast iron with a concrete inner coating, A high-pressure oxygen injection system was installed at 16 km from the pipe inlet, where severe anaerobic conditions appear. Experiments on oxygen injection were carried out with three different concentrations (7, 15 and 30 mg l(-1) O2). In all experiments, oxygen dissolved properly after injection, and no gas escapes were detected during water transportation. Most oxygen was consumed in the nitrification process, due to the low COD/NH4-N ratio, leading to a maximum production of oxidized nitrogen compounds of 7.5 mg l(-1) NO(x)-N with the 30 mg l(-1) O2 dose. Nitrification occured with nitrite accumulation, attributed to the presence of free ammonia within the range 1.2-1.4 mg l(-). Once the oxygen had been consumed, an apparent half-order denitrification took place, with limitation of biodegradable organic matter. The anoxic conditions led to a complete inhibition of sulphide generation.

Transportation of reclaimed wastewater through a long pipe: inhibition of sulphide production by nitrite from the secondary treatment.

The agricultural reuse of reclaimed wastewater has become a necessity in places with water shortages. Frequently, this involves the operation of long transportation pipelines, like in the South Tenerife reuse system, whose main element is a completely filled 61 km long gravity pipe in cast iron. Sulphide generation, which could contribute to pipe corrosion, is a usual process taking place during transportation if anaerobic conditions prevail. In the Wastewater Treatment Plant of Santa Cruz (Tenerife, Spain) a partial nitrification process was achieved by increasing the mean residence time through the aeration step at low dissolved oxygen concentration. Such conditions, combined with the right temperature and a free ammonia concentration above 1 mg l(-1), inhibited nitratation and favoured nitritation, which led to concentrations of NO2-N above 8 mg l(-1) in the secondary effluent. During the transportation, nitrite inhibited the appearance of anaerobic conditions, and, consequently, no sulphide generation occurred. At the same time, a nitrite reduction process took place with a first order kinetics and a rate coefficient of 0.052 h(-1)' at 25 degrees C. A parallel behaviour between the nitrite depletion and the oxidation-reduction potential evolution along the pipeline was also observed.

Cholinergic facilitation of erection and ejaculation in spinal cord-transected rats.

Penile reflexes (PRs) were monitored in chronic spinal cord-transected rats by identifying them visually, and at the same time they were recorded as the electromyographic activity of bulbospongiosus muscles. Intraperitoneal injection of the agonist muscarine (10 microg) produced a facilitation of PRs. A decrease in the latency, an increase in the number of clusters and often an increase in the duration of cups were found after muscarine. In addition, 66% (six out of nine) of the animals ejaculated after muscarine. These results suggest that cholinergic receptor stimulation may be involved in erectile and ejaculatory mechanisms mediated by the spinal cord.

Compatibility of staining protocols for bone tissue with Raman imaging.

We report the use of Raman microscopy to image mouse calvaria stained with hematoxylin, eosin and toluidine blue. Raman imaging of stained specimens allows for direct correlation of histological and spectral information. A line-focus 785 nm laser imaging system with specialized near-infrared (NIR) microscope objectives and CCD detector were used to collect approximately 100 x 450 micro m Raman images. Principal components analysis, a multivariate analysis technique, was used to determine whether the histological stains cause spectral interference (band shifts or intensity changes) or result in thermal damage to the examined tissue. Image analysis revealed factors for tissue components and the embedding medium, glycol methacrylate, only. Thus, Raman imaging proved to be compatible with histological stains such as hematoxylin, eosin and toluidine blue.

How partial nitrification could improve reclaimed wastewater transport in long pipes.

Reclaimed wastewater transport is studied in a concrete-lined cast iron pipe, where a nitrification-denitrification process occurs. The pipe is part of the Reuse System of Reclaimed Wastewater of South Tenerife (Spain), 0.6 m in diameter and 61 km long. In order to improve wastewater quality, at 10 km from the inlet there is injection of fresh water saturated in dissolved oxygen (DO), after which a fast nitrification process usually appears (less than two hours of space time). The amount of oxidized nitrogen compounds produced varies between 0.8 and 4.4 mg/l NOx(-)-N. When DO has disappeared, a denitrification process begins. The removal of nitrite is complete at the end of the pipe, whereas the nitrate does not disappear completely, leaving a concentration of about 0.4-0.5 mg/l. For a COD/NOx(-)-N ratio higher than 5, a first order nitrification rate in NOx(-)-N has resulted, with the constant k20 = 0.079 h-1, for a NOx(-)-N concentration range of 0.8-4.4 mg/l. Finally the following temperature dependency for the first order denitrification rate constant has been found: k = k20 x 1 x 15T-20. Although nitrogen could be used as nutrient in the agricultural reuse, its removal from reclaimed wastewater could be useful in order to diminish the chlorine needs for reclaimed wastewater disinfection.

Muscarinic mediation of the urethro genital reflex in spinal cord-transected rats.

The effects of muscarinic receptor stimulation were tested on the urethro genital reflex (UGR) in anesthetized and spinal cord-transected rats. Drugs were applied directly to the spinal cord. The electromyographic activity (EMG) of the bulbospongiosus (BS) muscle was used for recording UGR. In six animals BS as well as soleus, posterior biceps or peroneus tertius muscle EMG was recorded simultaneously. Muscarine (5, 10, 20, 50 and 100 microg) was applied in 22 animals after cutting L6-S1 dorsal roots. Some observations were made on another six animals, to which an extensive bilateral dorsal rhizotomy (L3-S2) was performed. Rhythmic bursts of similar frequency and size to those seen during UGR were found in BS muscle a few minutes after muscarine application. No rhythmic bursting was found on the hindlimb muscles, but exclusively on BS muscles. The effects of homatropine (25, 50, 100 and 200 microg), an acetylcholine muscarinic receptor antagonist, were tested in 21 rats after UGR was elicited three times at low stimulation intensity (7 mm Hg). Homatropine produced two effects: (i) A significant increase in the latency of UGR. (ii) A facilitation of UGR inhibition. In view of these results it can be speculated that muscarinic receptor stimulation is involved in the elicitation of UGR.