Light-Responsive and Dual-Targeting Liposomes: From Mechanisms to Targeting Strategies.

In recent years, nanocarriers have played an ever-increasing role in clinical and biomedical applications owing to their unique physicochemical properties and surface functionalities. Lately, much effort has been directed towards the development of smart, stimuli-responsive nanocarriers that are capable of releasing their cargos in response to specific stimuli. These intelligent-responsive nanocarriers can be further surface-functionalized so as to achieve active tumor targeting in a sequential manner, which can be simply modulated by the stimuli. By applying this methodological approach, these intelligent-responsive nanocarriers can be directed to different target-specific organs, tissues, or cells and exhibit on-demand controlled drug release that may enhance therapeutic effectiveness and reduce systemic toxicity. Light, an external stimulus, is one of the most promising triggers for use in nanomedicine to stimulate on-demand drug release from nanocarriers. Light-triggered drug release can be achieved through light irradiation at different wavelengths, either in the UV, visible, or even NIR region, depending on the photophysical properties of the photo-responsive molecule embedded in the nanocarrier system, the structural characteristics, and the material composition of the nanocarrier system. In this review, we highlighted the emerging functional role of light in nanocarriers, with an emphasis on light-responsive liposomes and dual-targeted stimuli-responsive liposomes. Moreover, we provided the most up-to-date photo-triggered targeting strategies and mechanisms of light-triggered drug release from liposomes and NIR-responsive nanocarriers. Lastly, we addressed the current challenges, advances, and future perspectives for the deployment of light-responsive liposomes in targeted drug delivery and therapy.

Mesenchymal stem cells attenuate the proinflammatory cytokine pattern in a guinea pig model of chronic cigarette smoke exposure.

AIMS: Cigarette smoke often induces pulmonary and systemic inflammation. In animal models, mesenchymal stem cells (MSC) tend to ameliorate these effects. We aimed to explore the local and systemic expression of cytokines in guinea pigs chronically exposed to cigarette smoke, and their modifications by MSC. MAIN METHODS: Concentrations of IL-1ß, IL-6, IL-8, IL-12, TNF-α, INF-É£, TSG-6, MMP-9, TIMP-1, and/or TIMP-2 in serum and bronchoalveolar lavage (BALF) from animals exposed to tobacco smoke (20 cigarettes/day, 5 days/week for 10 weeks) were determined, and mRNA expression of some of them was measured in lung tissue. Intratracheal instillation of allogeneic bone marrow MSC (5x106 cells in 1 ml) was done at week 2. KEY FINDINGS: After cigarette smoke, IL-6 and IFN-γ increased in serum and BALF, while IL-1ß and IL-12 decreased in serum, and TSG-6 and TIMP-2 increased in BALF. IL-1ß had a paradoxical increase in BALF. MSC had an almost null effect in unexposed animals. The intratracheal administration of MSC in guinea pigs exposed to cigarette smoke was associated with a statistically significant decrease of IL-12 and TSG-6 in serum, as well as a decrease of IL-1ß and IFN-γ and an increase in TIMP-1 in BALF. Concerning mRNA expression in lung tissue, cigarette smoke did not modify the relative amount of the studied transcripts, but even so, MSC decreased the IL-12 mRNA and increased the TIMP-1 mRNA. SIGNIFICANCE: A single intratracheal instillation of MSC reduces the pulmonary and systemic proinflammatory pattern induced by chronic exposure to cigarette smoke in guinea pigs. TRIAL REGISTRATION: Not applicable.

Characteristic plethysmographic findings in a guinea pig model of COPD.

AIM OF THE STUDY: Long-term exposure to cigarette smoke generates chronic obstructive pulmonary disease (COPD) in guinea pigs, but a comprehensive evaluation of changes in lung function, as assessed by barometric whole body plethysmography (WBP), is lacking. MATERIALS AND METHODS: Female guinea pigs were exposed to the smoke of 20 cigarettes/day, 5 days/week, during 10 weeks (COPD group, n = 8), and were compared with unexposed female guinea pigs of the same age (control group, n = 8). WBP was performed in both groups, followed by lung histology. RESULTS: At the end of the exposure period, guinea pigs in the COPD group had higher respiratory frequency, while duty cycle (Ti/Ttot) was unaffected. There was a trend toward minute ventilation (MV) and expiratory flow at the mid-tidal volume (EF50) to be higher in the COPD group. Enhanced pause (Penh) was lower, while time of braking (TB) and time to PEF relative to Te (Rpef) were higher in the COPD group. All guinea pigs exposed to tobacco smoke developed emphysematous lesions in their lungs and gained less body weight than controls. CONCLUSIONS: In this COPD model, exposure to cigarette smoke produced changes in WBP characterized by a shallow breathing pattern with decreased Penh and a trend toward increasing EF50 (probably due to decreased elastic recoil), increased TB (suggesting dynamic laryngeal narrowing), and a trend of increasing MV (probably due to a higher metabolic rate). Many of these functional changes resemble those observed in patients with COPD and corroborate the suitability of this guinea pig model for the study of COPD.

Modifications of plasma 5-HT concentrations during the allergic bronchoconstriction in guinea pigs.

Several contractile mediators involved in the antigen-induced airway obstruction have been identified, but the role of 5-HT (5-hydroxytryptamine or serotonin) has been scantily investigated. In this work, the potential role of 5-HT in the allergic bronchoconstriction was evaluated through a pharmacological approach and plasma 5-HT measurement in blood samples from the right and left ventricles of anesthetized guinea-pigs. Intravenous 5-HT caused a dose-dependent increase of the lung resistance in anesthetized, nonsensitized guinea pigs. Likewise, in sensitized animals the antigenic challenge with ovalbumin also caused a transient bronchoconstriction (356 ± 60% the basal value), which was largely inhibited by the blockade of serotonergic receptors with methiothepin plus tropisetron (134 ± 10%, P = .007). Sensitized animals tended to have plasma 5-HT concentrations higher than nonsensitized controls, and shortly after the peak of the allergic bronchoconstriction the 5-HT levels in the left ventricle (blood flowing out from lungs) tended to be higher than in the right ventricle (blood entering the lungs), although data dispersion precluded the obtaining of statistical significance. Interestingly, the degree of bronchoconstriction highly correlated with the concentrations of 5-HT found in the left ventricle and measured either in platelet-rich plasma (r = 0.97 P = .007) or platelet-poor plasma (r = 0.97, P = .006). After the obstructive response subsided these correlations were lost, but now the degree of bronchoconstriction turned to be correlated with 5-HT concentration in platelet concentrate (r = 0.76, P = .03). In conclusion, our results suggested that 5-HT is actively released from lungs during the antigenic challenge and that this autacoid is involved in the generation of the airway obstruction.

Passive smoking induces leukotriene production in children: influence of asthma.

BACKGROUND: Passive smoking is associated with poor asthma control in children, but the mechanism is unknown. Leukotrienes are involved in the asthma pathogenesis and their synthesis is increased in adult subjects who actively smoke. OBJECTIVE: To evaluate whether passive smoking, as assessed by urinary cotinine levels, increases leukotriene production in children with or without asthma. METHODS: This was a prospective, cross-sectional study in which children with stable intermittent asthma (without exacerbation) and healthy control children were studied through spirometry and urinary concentrations of cotinine and leukotriene E(4) (LTE(4)). Both groups were balanced to include children with and without passive smoking. RESULTS: Ninety children (49 with asthma and 41 controls, 54.4% females) aged 9 years (range, 5-13 years) were studied. Urinary LTE(4) concentrations were progressively higher as cotinine levels increased (r(S) = 0.23, p = .03). LTE(4) also correlated with body mass index (BMI) (r(S) = 0.30, p = .004), and multiple regression analysis revealed that BMI was even more influential than cotinine for determining LTE(4) levels. LTE(4) concentrations were unrelated with gender, age, or spirometry. In turn, cotinine inversely correlated with forced expiratory volume in one second (FEV(1)) (r(S) = -0.22, p = .04) and forced vital capacity (FVC) (r(S) = -0.25, p = .02), but when analyzed by groups, these relationships were statistically significant only in children with asthma. CONCLUSIONS: Exposure to environmental tobacco smoke, as assessed by urinary cotinine levels, was associated with an increased urinary concentration of LTE(4), although BMI exerted more influence in determining its concentration. Urinary cotinine was associated with decreased lung function, mainly in children with asthma.

[General aspects of pulmonary innervation]. / Aspectos generales de la inervación pulmonar.

Practically all organs of the respiratory system are under the control of the autonomic nervous system. Double vegetative innervation, sympathetic and parasympathetic, contributes to the regulation of airway smooth muscle tone, and modulates secretion from the submucosal glands. Nevertheless, more than 20 years ago, the classical view of excitatory cholinergic and inhibitory adrenergic innervation changed considerably when the existence was proved of the non-adrenergic non-cholinergic system (NANC), which is able to produce both effects. Several purines and peptides have been postulated as neurotransmitters of this system, and some of them coexist with the acetylcholine or norepinephrine; for example, vasoactive intestinal peptide (VIP) on cholinergic nerves and neuropeptide Y in the adrenergic nerves. The aim of this paper is to describe the anatomo-physiological aspects of the airways' autonomic innervation and the possible implication of a neural mechanism that contributes in the development of the symptomatology in respiratory diseases.

Isolated Lung Perfusion System in the Rabbit Model.

The isolated lung perfusion system has been widely used in pulmonary research, contributing to elucidate the lungs' inner workings, both micro and macroscopically. This technique is useful in the characterization of pulmonary physiology and pathology by measuring metabolic activities and respiratory functions, including interactions between circulatory substances and the effects of inhaled or perfused substances, as in drug testing. While in vitro methods involve the slicing and culturing of tissues, the isolated ex vivo lung perfusion system allows to work with a complete functional organ making possible the study of a continuous physiological function while recreating ventilation and perfusion. However, it should be noted that the effects of the absence of central innervation and lymphatic drainage still have to be fully assessed. This protocol aims to describe the assembly of the isolated lung apparatus, followed by the surgical extraction and cannulation of lungs and heart from experimental lab animals, as well as to display the perfusion technique and signal processing of data. The average viability of the isolated lung ranges between 5-8 h; during this period, the pulmonary capillary permeability increases, causing edema and lung injury. The functionality of preserved pulmonary tissue is measured by the capillary filtration coefficient (Kfc), used to determine the extent of pulmonary edema through time.

Effect of Azadirachta indica A. Juss (Meliaceae) on the serotonin rhythm of Spodoptera frugiperda (Lepidoptera: Noctuidae).

Circadian rhythms are an adaptive response of organisms to the environment that enables them to measure time. Circadian rhythms are some of the most studied biological rhythms. Serotonin (5HT) has been proposed as their modulator of circadian rhythms, playing a pivotal role in their establishment. However, 5HT concentrations are altered in insect organisms when they feed on some plant extracts. Insects show a variety of rhythms. The larval stage of the lepidopteran Spodoptera frugiperda is a pest of economically important crops. As a response, plants have developed secondary metabolites, such as azadirachtin, obtained from Azadirachta indica. We assessed the circadian rhythm of 5HT in the brain and digestive tube of larvae of S. frugiperda; furthermore, the effect of A. indica extract on the oscillations was evaluated. 5HT modulates the rhythms of locomotor activity, and if extracts of A. indica alter the concentration of 5HT, it can indirectly alter the rhythms of locomotor activity, as well as peristaltic movements of the intestine. Larvae were exposed to a 12 h:12 h light-dark (LD) photoperiod, and half of them remained for 72 h under constant darkness (DD). Tissue samples were obtained at six different times during a single 24 h period, and the amount of 5HT was quantified by high-performance liquid chromatography (HPLC). Data were statistically compared by a one-way ANOVA followed by a Tukey post hoc test and subjected to Cosinor analysis for assessment of 24 h rhythmicity. The results showed that the A. indica methanolic extract had an effect on the 5HT concentration of the brain and digestive tube of the larvae. In the brain, the 5HT increase in larvae fed with the extract could alter memory, learning, sleep, and locomotor activity processes. Whereas in the intestine, the 5HT decrease in the larvae fed with the extract could decrease peristalsis movements and, therefore, indirectly influence the antifeedant effect.

[Airway resistance and urinary LTE4 in children with bronchopulmonary dysplasia. Preliminary report]. / Resistencia de las vías aéreas y LTE4 urinario en niños con displasia broncopulmonar. Informe preliminar.

OBJECTIVE: To assess airway resistance values and urinary leukotriene E4 (LTE4) concentrations before and after salbutamol inhalation in children with bronchopulmonary dysplasia (BPD). MATERIAL AND METHODS: Children with BPD were cross-sectionally studied to measure airway resistance by the interrupter technique (Rint), before and after inhaling 200 ig salbutamol, and to quantify urinary leukotriene E4 (LTE4) by immunoassay. RESULTS: Thirty one children with BPD (15 females) aged between 3 months and 9 years were studied. Our results showed that LTE4 did not correlate with Rint values (r = 0.12, p = 0.52) even after adjusting by gender, atopy history, steroid use, and gastroesophageal reflux. Likewise, LTE4 did not correlate with the degree of the airway response to salbutamol (r = -0.13, p = 0.50). A strong inverse association between age and Rint (r = -0.58, p < 0.001) was observed. CONCLUSION: We concluded that urinary LTE, did not correlate with airway resistance or with the response to a bronchodilator drug in children with BPD, suggesting that leukotrienes are not involved in airway obstruction in this disease.

Mold burden in house dust and its relationship with asthma control.

OBJECTIVE: Some evidences indicate that exposure to molds or their products can be relevant for the loss of asthma control. Thus, we measured the mold burden present inside houses of subjects with asthma, and evaluated its relationship with asthma control. METHODS: Markers of asthma control in adult patients residing in Mexico City were evaluated through questionnaires and spirometry. Dust was collected from the patients' houses and its fungal content was determined by mold specific quantitative PCR (MSQPCR) for 36 fungal species. RESULTS: Forty-two patients with asthma (12 males, 30 females) with a mean age of 45 years (18-76 years) were included in the study. The level of asthma control measured through the Asthma Control Test ranged from 9 to 25 (mean 20.9). The FEV1/FVC ratio fluctuated from 38 to 106 %predicted (mean, 87.4 %predicted). Associations between mold burden and asthma control differed between males and females. Thus, concentrations of some molds, particularly Aspergillus fumigatus, Aureobasidium pullulans, Stachybotrys chartarum, Alternaria alternata, Cladosporium cladosporioides 2, Cladosporium herbarum, and Epicoccum nigrum, were negatively associated with parameters of asthma control in male subjects, but not in female patients. CONCLUSION: Our results showed that potential indoor exposure to some molds is associated with less asthma control in male subjects.

Allergic sensitization modifies the pulmonary expression of 5-hydroxytryptamine receptors in guinea pigs.

There is mounting evidence that 5-hydroxytryptamine (5-HT) plays a role in asthma. However, scarce information exists about the pulmonary expression of 5-HT receptors and its modification after allergic sensitization. In the present work, we explored the expression of 5-HT1A, 5-HT2A, 5-HT3, 5-HT4, 5-ht5a, 5-HT6, and 5-HT7 receptors in lungs from control and sensitized guinea pigs through qPCR and Western blot. In control animals, mRNA from all receptors was detectable in lung homogenates, especially from 5-HT2A and 5-HT4 receptors. Sensitized animals had decreased mRNA expression of 5-HT2A and 5-HT4 receptors and increased that of 5-HT7 receptor. In contrast, they had increased protein expression of 5-HT2A receptor in bronchial epithelium and of 5-HT4 receptor in lung parenchyma. The degree of airway response to the allergic challenge was inversely correlated with mRNA expression of the 5-HT1A receptor. In summary, our results showed that major 5-HT receptor subtypes are constitutively expressed in the guinea pig lung, and that allergic sensitization modifies the expression of 5-HT2A, 5-HT4, and 5-HT7 receptors.

¿Qué es la circulación extracorpórea? Aspectos técnicos / What is a bypass? Technical aspects

El presente trabajo pretende describir algunos conceptos básicos del bypass cardiopulmonar cuando es utilizado en protocolos de investigación en modelos animales. Describimos los aspectos técnicos de interés que debe conocer el investigador y el personal que trabaja en centros hospitalarios donde se realizan estos procedimientos de perfusión. El perfusionista es el especialista calificado en manejar la bomba de circulación extracorpórea durante situaciones médicas donde es necesario el soporte temporal de la función circulatoria. Además, es el experto en el conocimiento de la variedad de equipo y es responsable de su buen funcionamiento. Está capacitado para poder administrar algunos medicamentos de acuerdo al protocolo de perfusión. Es así como describimos parte del equipo de circulación extracorpórea, y algunos aspectos fisiológicos durante el bypass cardiopulmonar. En esta monografía no intentamos discutir la multitud de variaciones posibles de cómo realizar el bypass cardiopulmonar, sino que muestra los principios básicos para poder entender los circuitos extracorpóreos

Utilización de pericardio bovino tratado con glutaraldehido liofilizado, en la reparación de defectos abdominales en ratas / Use of lyophilized glutaraldehyde treated bovine pericardium to repair abdominal defects in rats

Objetivo. Evaluar la utilidad del pericardio bovino tratado con glutaraldehido (PBYG) al 0.5 por ciento y liofilizado (PBTGL), en la reparación de defectos abdominales en ratas, comparándolo con PBTG preservado al 0.5 por ciento sin liofilizar y con pericardio bovino preservado con solución de Hank liofilizado (PBTHL). Diseño. Estudio experimental, prospectivo y con grupo control. Se empleo prueba de Chi cuadrada. Sede. Departamento de cirugía experimental del Instituto Nacional de Enfermedades Respiratorias, en México, D.F. Material y métodos. Utilizamos 30 ratas Wistar que fueron divididas en tres grupos de estudio, se les disecó y resecó un segmento de la pared abdominal ventral, lo que produjo un defecto de aproximadamente 2 x 1.5 cm que fue reparado con una bioprótesis de pericardio bovino. Grupo I. Reparación de la pared abdominal con pericardio bovino tratado con glutaraldehido al 0.5 por ciento (PBTG) (n=10). Grupo II. Reparación de la pared abdominal con PBTG liofilizado preservado al 0.5 por ciento (PBTGL) (n=10). Grupo III. Reparación del defecto con pericardio bovino preservado en solución de Hank liofilizado (PBTHL) (N=10). Los animales fueron evaluados clínicamente, diario la primera semana postcirugía, y cada tercer día el tiempo restante. Al finalizar el estudio los animales se sometieron a eutanasia con una sobredosis de pentobarbital sódico y se evaluó macroscópica y microscópicamente el estado de la bioprótesis. Resultados. Todos los animales sobrevivieron al procedimiento quirúrgico y al tiempo de estudio, que fue de 8 semanas. En los grupos I y II, macroscópicamente la bioprótesis se adaptó bien a la pared abdominal, no así en el grupo III en donde el material implantado fue rechazado. Microscópicamente, los animales de los grupos I y II, presentaron buena cicatrización con proliferación de fibroblastos y depósitos de colágena sobre y en la periferia de la prótesis, así como vasos sanguíneos de neoformación. En el grupo III se observó necrosis tanto en el borde quirúrgico como en la prótesis, con una reacción inflamatoria severa y numerosas células gigantes a cuerpo extraño. conclusión. El liofilizar el PBTG permite un mejor almacenamiento y transporte del mismo, además de que al rehidratarlo mantiene su resistencia, fácil manejo quirúrgico, no se rechaza y se integra bien al tejido muscular

Utilización de bioprótesis liofilizadas en la reparación de defectos abdominales en ratas / Use of lyophilized bioprosthesis in the repair of abdominal defects in rats

En el presente trabajo evaluamos la utilidad del pericardio de bovino tratado con glutaraldehído al 0.5 por ciento preservado liofilizado en la reparación de defectos abdominales en ratas. utilizamos 20 ratas Wistar que fueron divididas en dos grupos de estudio, a las cuales se les disecó y resecó un segmento de la pared abdominal ventral lo que produjo un defecto de aproximadamente 2 x 1.5 cm y fue reparado con una bioprótesis de pericardio de bovino. Grupo I: Reparación de la pared abdominal con pericardio bovino tratado con glutaraldehído al 0.5 por ciento (n= 10); Grupo II: Reparación de la pared abdominal con pericardio de bovino tratado con glutaraldehído liofilizado preservado al 0.5 por ciento (n= 10). Los animales fueron evaluados a diario clínicamente durante la primera semana postcirugía y cada tercer día, el tiempo restante. Al finalizar el estudio, los animales se sometieron a eutanasia con una sobredosis de pentobarbital sódico y se evaluó macroscópica y microscópicamente el estado de la bioprótesis. Todos los animales sobrevivieron al procedimiento quirúrgico y al tiempo de estudio que fue de 8 semanas. En los dos grupos, macroscópicamente, la bioprótesis se adaptó bien a la pared abdominal. Microscópicamente los animales de ambos grupos presentaron buena cicatrización con proliferación de fibroblastos y depósitos de colágena sobre y en la periferia de la prótesis así como vasos sanguíneos de neoformación. El liofilizar el pericardio bovino tratado con glutaraldehído al 0.5 por ciento permite un mejor almacenamiento y transporte del mismo, además de que al rehidratarlo mantiene su resistencia, su fácil manejo quirúrgico y no se rechaza

Reconstrucción del esternón con pericardio bovino tratado con glutaraldehído (PBTG): estudio experimental / Reconstruction of the sternum with glutaralheyde preserved bovine pericardium (GPBP). an experimental sudy

Presentamos los resultados obtenidos en la reconstrucción de la pared anterior del tórax en un grupo de siete perros, utilizando como bioprótesis pericardio bovino tratado con glutaraldehído (PBTG), preparado en nuestro Laboratorio de Cirugía Experimental (INER). Al grupo experimental se les resecó el tercio inferior del esternón de la sexta a la novena costilla, incluyendo el apéndice xifoides, creándose un defecto anatómico de aproximadamente 12 x 8 cm, que fue reconstruido mediante bandas y parches de PBTG. Los animales fueron estudiados durante 90 días, presentando evolución clínica satisfactoria, cicatrización normal y sin infección o dehiscencia de la bioprótesis

El animal de laboratorio / The laboratory animal

La utilización de animales de laboratorio para la investigación biomédica ha tenido un crecimiento importante en nuestro país en los últimos años. La clase de estos animales influyen directamente en la calidad de los trabajos científicos realizados con ellos. El presente trabajo tiene por objeto exponer un panorama general de lo que es el animal de laboratorio. Se analizan las razones de tipo científico, ético-legales y laborales que obligan a que la calidad de estos animales sea apropiada. Se describen las características microbiológicas de los animales convencionales y aquellos clasificados como libres de patógenos específicos. Además, se describen las características físicas que debe terner el albergue para animales de laboratorio. Se concluye que el animal de laboratorio es un modelo biológico de gran valor para la investigación, por lo que su producción y cuidado deben responder a estrictas normas de calidad que aseguren que su uso sea científica y éticamente aceptable

Estudio morfométrico del árbol traqueobronquial en ratas / Morphometric study of the tracheobronchial tree in rats

En este estudio se realizaron mediciones anatómicas del árbol traqueobronquial de ratas, con el fin de conocer las dimensiones de éste, para facilitar la ejecución de procedimientos invasivos durante los proyectos de investigación que emplean ratas. Sesenta ratas Wistar fueron sleccionadas en seis grupos de acuerdo con su peso (n= 10 cada uno); G1, 100-200 g; G2 201-300 g; G3 301-400 g; G4 401-500 g; G5 501-600 g; G6 601-800 g. En cada grupo los resultados fueron expresados como promedio ñ error estándar del promedio. Se realizó análisis de correlación simple. Nuestros resultados muestran que la extensión y el diámetro del árbol traqueobronquial aumenta conforme aumenta el peso corporal y la longitud de la rata. Consideramos que esta información es de utilidad para los investigadores que requieren trabajar en el árbol traqueobronquial de esta especie

Efecto de la prednisona, la azatioprina y la ciclosporina A sobre la cicatrización bronquial / Effects of prednisone, azathioprine and ciclosporine A on bronchial healing

El trasplante pulmonar es la única posibilidad terapéutica para los pacientes con pulmón en estado terminal; sin embargo, las complicaciones que se presentan después del transplante como la cicatrización bronquial deficiente, no han permitido que esta medida terapéutica sea muy exitosa. Esta complicación puede ser el resultado de varios factores como la inmunosupresión, la isquemia, las infecciones y/o el fenómeno de rechazo. En este trabajo se estudió el efecto de tres inmunosupresores (prednisona, azatioprina y ciclosporina A) en la cicatrización bronquial, en un modelo de autotransplante pulmonar canino. Se usaron tres parámetros comparativos para evaluar el efecto de los inmunosupresores sobre la anastomosis bronquial: el histológico (evaluación subjetiva de la cantidad de colágena que aparece en la anastomosis), la cuantificación de la concentración de la colágena por el método de Woessner y la medición de la fuerza tensil de ruptura (FTR). El grupo de prednisona a dosis alta mostró índice histológico de la colágena significativamente menor con respecto de los demás grupos. De la misma forma, la FTR fue también significativamente menor en el grupo de prednisona a dosis alta. La concentración de la colágena depositada no presentó diferencia entre ninguno de los grupos. Se concluye que las dosis altas de prednisona (4 mg/kg/día), afectan la anastomosis bronquial, pues disminuyen significativamente la FTR y el índice histológico de la colágena que se observó; sin embargo, este efecto no se debió a la cantidad de la colágena depositada, sino probablemente a la forma de depositarse de ésta o a una polimerización deficiente

Utilidad del pericardio bovino tratado con glutaraldehído en resecciones pulmonares no anatómicas en perros / Effects of glutaraldehyde preseved bovine pericardium in non-anatomic pulmonary resection in dogs

En el presente trabajo evaluamos la utilidad, cicatrización, cambios macroscópicos y microscópicos del pericardio bovino tratado con glutaraldehído (PBTG) preparado en nuestro laboratorio al reforzar resecciones no anatómicas de tejido pulmonar en perros. Utilizamos 12 perros mestizos que fueron divididos en dos grupos de estudios a los cuales se les resecó el 30 por ciento del lóbulo craneal del pulmón derecho y dicha resección fue reforzada con tiras de pericardio bovino tratado con glutaraldehído. Grupo I (n = 6), las tiras de pericardio bovino tratado con glutaraldehído se fijaron con material de sutura no absorbible. Grupo II (n = 6), la resección y fijación de las tiras de pericardio bovino tratado con glutaraldehído se llevó a cabo por medio de una engrapadora. Los animales fueron evaluados clínicamente y radiológicamente a diario durante la primera semana postcirugía y, cada tercer día el tiempo restante. Al finalizar el estudio fueron sometidos a eutanasia con sobredosis de pentobarbital sódico y se evaluó macroscópica y microscópicamente el estado de la bioprótesis y el pulmón. Todos los animales sobrevivieron al procedimiento quirúrgico y al tiempo de estudio que fue de ocho semanas, sin presentar ninguna alteración clínica o radiológica. En los dos grupos, macroscópicamente, el pericardio bovino tratado con glutaraldehído se adaptó bien el tejido pulmonar. Microscópicamente los animales de ambos grupos presentaron buena cicatrización con presencia de una capa de tejido fibroso sobre y en la periferia del pericardio bovino tratado con glutaraldehído y pulmón. Sin embargo, en el grupo I se observaron células gigantes a cuerpo extraño en la zona de las suturas. El pericardio bovino tratado con glutaraldehído preparado en nuestro laboratorio es un material útil para el reforzamiento de resecciones pulmonares no anatómicas en perros

Evaluación de cambios hemodinámicos y gasométricos producidos por neumoperitoneo experimental con bióxido de carbono y helio en perros / Evaluation of hemodynamic and blood gases changes produced by experimental pneumoperitoneum using carbon dioxide and helium in dogs

La cirugía laparoscópica ha llegado a ser clínicamente relevante. Siempre que se lleva a cabo este tipo de cirugías se tiene que insuflar la cavidad abdominal con dióxido de carbono (CO2). Nosotros evaluamos el uso de CO2 y helio (He) en la producción de neumoperitoneo experimental. Doce perros mestizos fueron sometidos a neumoperitoneo bajo anestesia con halotano al 1 por ciento. Todos los animales se ventilaron mecánicamente con volumen 15 mL/kg, frecuencia respiratoria de 20/min y 100 por ciento de fracción inspirada de O2. Los animales fueron divididos en 2 grupos de estudio. Grupo I: (n = 6) se les produjo neumoperitoneo experimental con CO2 y grupo II: (n = 6) neumoperitoneo experimental con He. El neumoperitoneo se estableció a través de un trocar de 5 mm que se insertó a nivel de la cicatriz umbilical. La presión de insuflación de la cavidad fue de 10 cmH2O durante 30 minutos, 15 cmH2O por 30 minutos y 20 cmH2O también durante 30 minutos. Los parámetros hemodinámicos, gases sanguíneos y la presión inspiratoria máxima fueron evaluados después de la insuflación cada 30 minutos de establecido el neumoperitoneo y 30 minutos después de desinsuflar el abdomen. En los resultados se observó que el gasto cardiaco disminuyó en ambos grupos durante la producción del neumoperitoneo. La presión venosa central (PVC) y la resistencia vascular pulmonar se mantuvo similar en ambos grupos. Las gasometrías del grupo I mostraron incrementó en la pCO2 venosa a los 30 minutos de haberse iniciado el neumoperitoneo, a los 30 mintos de mantener la presión a 20 cmH2O y al finalizar el estudio, mientras que el grupo II no sufrió cambios. La presión inspiratoria máxima (PIM) se incrementó en ambos grupos. Concluimos que no hay diferencia entre la producción del neumoperitoneo con CO2 o He.