Cobalt Chloride as a Hypoxia Mimicking Agent Induced HIF-1α and mTOR Expressions of Human Umbilical Cord Mesenchymal Stem Cells

ABSTRACT Objective: To assess the effects of cobalt chloride (CoCl2) as a hypoxia mimicking agent on human umbilical cord mesenchymal stem cells (hUCMSCs) expression of HIF-1α and mTOR for use in regenerative dentistry. Material and Methods: Human umbilical cord mesenchymal stem cells were isolated and then cultured. The characteristics of stemness were screened and confirmed by flow cytometry. The experiment was conducted on hypoxia (H) and normoxia (N) groups. Each group was divided and incubated into 24-, 48-, and 72-hours observations. Hypoxic treatment was performed using 100 µM CoCl2 on 5th passage cells in a conventional incubator (37°C; 5CO2). Then, immunofluorescence of HIF-1α and mTOR was done. Data was analyzed statistically using One-way ANOVA and Tukey's HSD. Results: Significant differences were found between normoxic and hypoxic groups on HIF-1α (p=0.015) and mTOR (p=0.000) expressions. The highest HIF-1α expression was found at 48 hours in the hypoxia group, while for mTOR at 24 hours in the hypoxia group. Conclusion: Hypoxia using cobalt chloride was able to increase human umbilical cord mesenchymal stem cells expression of HIF-1α and mTOR.

Research Progress on Molecular Changes in Pulmonary Hypoxia and Cause of Death Identification in Mechanical Asphyxia / 法医学杂志

Lung is the largest organ of the respiratory system. During hypoxia, pulmonary cells undergo rapid damage changes and activate the self-rescue pathways, thus leading to complex biomacromolecule modification. Death from mechanical asphyxia refers to death due to acute respiratory disorder caused by mechanical violence. Because of the absence of characteristic signs in corpse, the accurate identification of mechanical asphyxia has always been the difficulty in forensic pathology. This paper reviews the biomacromolecule changes under the pulmonary hypoxia condition and discusses the possibility of application of these changes to accurate identification of death from mechanical asphyxia, aiming to provide new ideas for related research.

Male reproductive system and simulated high-altitude environment: preliminary results in rats / 亚洲男科学杂志(英文版)

This study assessed the effects of a simulated high-altitude environment on the reproductive system of prepubertal male rats and the reversibility of these effects upon return to a normal environment. Three-week-old male Wistar rats were randomly allocated to 4 groups that were exposed to different conditions: a normal environment for 6 weeks and 12 weeks, respectively, hypobaric hypoxia for 6 weeks, and hypobaric hypoxia for 6 weeks followed by a normal environment for 6 weeks. Multiple pathophysiological parameters were evaluated at the histological, endocrine, and molecular levels. Hypobaric hypoxia exposure for 6 weeks during the prepubertal phase significantly altered physiological parameters, body functions, blood indices, and reproductive potential. Six weeks after returning to a normal environment, the damaged reproductive functions partially recovered due to compensatory mechanisms. However, several changes were not reversed after returning to a normal environment for 6 weeks, including disorders of body development and metabolism, increased red blood cells, increased fasting blood glucose, abnormal blood lipid metabolism, decreased testicular and epididymis weights, abnormal reproductive hormone levels, excessive apoptosis of reproductive cells, and decreased sperm concentration. In summary, a hypobaric hypoxic environment significantly impaired the reproductive function of prepubertal male rats, and a return to normal conditions during the postpubertal phase did not fully recover these impairments.

Hypoxic stimulation leads to the changes of inflammatory factors in mucosal epithelial cells of nasal polyps / 中华耳鼻咽喉头颈外科杂志

Objective: To investigate the roles of hypoxic stimulation in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) by comparing the variation and differences of inflammatory factors secreted from epithelial cells of nasal polyps and normal nasal mucosa under hypoxic stimulation. Methods: Sixty-eight patients who were diagnosed with CRSwNP from June 2015 to January 2018 at China-Japan Union Hospital of Jilin University were analyzed, including 36 males and 32 females, aged (45.2±12.5) years. Nasal polyps mucosa was included in CRS-NP group and inferior turbinate mucosa was included in CRS-IT group. According to the degree of eosinophil infiltration in histopathologic results, each of these two groups was further divided into eosinophil infiltration and non-eosinophil infiltration as Eos-NP group (n=34), Non-Eos-NP group (n=34), Eos-IT group (n=20) and Non-Eos-IT group (n=20). The inferior turbinate mucosa of twenty-five patients who were diagnosed with cyst of paranasal sinus or deviation of nasal septum was classified as control group (n=25), including 14 males and 11 females, aged (42.8±10.2) years. The expression of interleukin 17A (IL-17A), interferon γ (IFN-γ), tumor necrosis factor α (TNF-α) and hypoxia-inducible factor 1α (HIF-1α) in each group was analyzed by immunohistochemical staining. After 0, 24 and 48 h hypoxic stimulation, the secretion of IL-17A, IFN-γ, TNF-α in primary nasal mucosa epithelial cells of each group was tested by enzyme-linked immune sorbent assay (ELISA) experiment; the expression of HIF-1α was tested by immunofluorescent staining and imaging and Western blot. SPSS 17.0 software and two-way ANOVA were used for statistical analysis. Results: Immunohistochemical staining showed that the expression of IL-17A and TNF-α was much higher in control group (optical density (OD) value was 0.37±0.03, 0.53±0.02, respectively) and the expression of IFN-γ and HIF-1α was much higher in Eos-IT group (OD value was 0.47±0.03, 0.39±0.02, respectively). The secretion of IL-17A and TNF-α was much lower in control group than that in other groups under normal condition. After 48 h hypoxic stimulation, the secretion of IL-17A and TNF-α was much higher in control group compared with other groups. The secretion of IFN-γ in Eos-NP group was much higher than that in control group under normal condition ((13.7±1.3) pg/ml vs (11.1±1.6) pg/ml, P<0.05). After 48 h hypoxic stimulation, there was no difference of IFN-γ between control group and Eos-NP group. The expression of HIF-1α decreased in Eos-NP group and Non-Eos-NP group while increased in CRS-IT group and control group upon prolonged exposure to hypoxia. HIF-1α was mostly located at cytoplasm of epithelial cells in control and CRS-IT group while mainly located at nucleus of epithelial cells in CRS-NP group. Conclusions: The secretion of IL-17A, TNF-α, IFN-γ and the expression of HIF-1α show significant difference between normal nasal mucosa, polyps and inferior turbinate of CRSwNP under hypoxic stimulation, presenting different subcellular localization. This illustrates the proteins above are involved in transcription and regulation of the gene responsible for the pathogenesis of CRSwNP.

Histological analysis of the intestinal wall of newborn rats submitted to hypoxia and reoxygenation to evaluate the protective effect of N-Acetylcysteine

Abstract Purpose To evaluate the effect of N-Acetylcysteine (NAC) in newborn rats submitted to hypoxia and reoxygenation (H/R) conditions in an experimental model of necrotizing enterocolitis. Methods Eight pregnant rats and their 70 cubs were used (5 groups) and exposed to H/R conditions and received NAC at different times. The animals in the H/R groups were placed in a gas chamber (100% CO2) for 10 minutes and then reoxygenated for 10 minutes (100% O2), twice a day for the first three days of life, with a six-hour span between events. On the third day of life, the animals were anesthetized, laparotomized and the intestines were resected. Results The H/R and NAC groups showed changes in the intestinal wall in relation to the number, height and width of the villi when compared to the control group (p<0.0001), but with better preservation of structures in the NAC group. There were no differences between groups regarding the number (%) of mitoses. Conclusion The administration of NAC decreased the lesions in the intestinal wall of rats submitted to H/R, therefore suggesting that this drug can be used to prevent the development of necrotizing enterocolitis in newborns.

Efectos morfológicos y mecánicos en ratas Sprague Dawley sometidas a ciclos de hipoxia / Morphological and mechanical effects in Sprague Dawley rats subjected to hypoxia cycles

Periodos extensos de hipoxia provocan cambios adaptativos que permiten responder a las demandas impuestas por el ambiente. Sin embargo, existen casos donde esta exposición es intermitente, como es el caso de los trabajadores en zonas andinas. El objetivo de esta comunicación fue comprobar los efectos morfológicos y mecánicos en diafragma y pulmones de ratas sometidas a la hipoxia intermitente. Se utilizaron 4 ratas Sprague Dawley de 6 meses de edad. Dos ratas fueron sometidas a 10 ciclos de hipoxia hipobárica intermitente (HHI) de 96 h (~428 torr; PO2 90 mm Hg), seguidos de 96 h de normoxia normobárica, durante 80 días. Se realizaron pruebas tracción uniaxial y de tinción con HematoxilinaEosina y Picrosirius red de Junqueira. Al comparar las curvas de los diafragmas, los sometidos a hipoxia reducen levemente su esfuerzo respecto a la condición de normoxia, en el tejido pulmonar la hipoxia afecta negativamente su resistencia, estas muestran una pendiente menor respecto a las normóxicas. En el análisis histológico, el parénquima pulmonar presentó menor cantidad de vasos sanguíneos y celularidad, como una mayor fracción de área de los espacios alveolares y cantidad de colágeno total en el grupo HHI. En el diafragma, el grupo HHI presentó menor cantidad de miocitos distribuidos irregularmente y de colágeno total. En conclusión, los principales hallazgos indican que el diafragma y el tejido pulmonar sometido a HHI sufren cambios estructurales, que se traducen en una disminución en su capacidad de resistencia tensil.

Extensive periods of hypoxic cause adaptive changes that make it possible to respond to the demands imposed by the environment. However, there are cases where this exposure is intermittent, as is the case of workers in andean areas. The objective of this communication was to verify the morphological and mechanical effects on diaphragm and lungs of rats subjected to intermittent hypoxic. Four 6-monthold Sprague Dawley rats were used. Two rats were subjected to 10 cycles of intermittent hypobaric hypoxic (IHH) of 96 h (~428 torr, PO2 90 mm Hg), followed by 96 h of normobaric normoxia, for 80 days. Uniaxial traction and staining tests were performed with Hematoxylin-Eosin and Picrosirius red de Junqueira. When comparing the curves of the diaphragms, those subjected to hypoxic slightly reduce their effort with respect to the condition of normoxia, in the lung tissue the hypoxic negatively affects its resistance, these show a lower slope with respect to the normoxics. In the histological analysis, the pulmonary parenchyma had a lower number of blood vessels and cellularity, such as a greater area fraction of alveolar spaces and amount of total collagen in IHH group. In the diaphragm, IHH group had a lower number of irregularly distributed myocytes and a lower amount of total collagen. In conclusion, the main findings indicate that the diaphragm and lung tissue subjected to IHH undergo structural changes, which result in a decrease in tensile strength.

Temporal profile of intestinal tissue expression of intestinal fatty acid-binding protein in a rat model of necrotizing enterocolitis

OBJECTIVES: Necrotizing enterocolitis is a severe multifactorial intestinal disorder that primarily affects preterm newborns, causing 20-40% mortality and morbidity. Intestinal fatty acid-binding protein has been reported to be a biomarker for the detection of intestinal injuries. Our aim was to assess intestinal tissue injury and the molecular expression of intestinal fatty acid-binding protein over time in a necrotizing enterocolitis model. METHODS: A total of 144 Newborn rats were divided into two groups: 1) Control, which received breastfeeding (n=72) and 2) Necrotizing Enterocolitis, which received formula feeding and underwent hypoxia and hypothermia (n=72). A total of six time points of ischemia (2 times a day for 3 days; 12 pups for each time point) were examined. Samples were collected for analysis of body weight, morphological and histological characteristics, intestinal weight, intestinal weight/body weight ratio, injury grade, and intestinal fatty acid-binding protein levels. RESULTS: Body and intestinal weights were lower in the Necrotizing Enterocolitis group than in the Control group (p<0.005 and p<0.0005, respectively). The intestinal weight/body weight ratio was higher in the Necrotizing Enterocolitis group than in the Control group (p<0.005) only at the sixth ischemia time point. The Necrotizing Enterocolitis group displayed higher expression of intestinal fatty acid-binding protein (p<0.0005) and showed greater tissue damage than the Control group. CONCLUSION: Intestinal fatty acid-binding protein was an efficient marker of ischemic injury to the intestine and a good correlation was demonstrated between the time of ischemic injury and the grade of intestinal injury.

Relationship between the Expression of α-syn and Neuronal Apoptosis in Brain Cortex of Acute Alcoholism Rats / 法医学杂志

OBJECTIVES@#To observe the changes of expression of α-synuclein （α-syn） and neuronal apoptosis in brain cortex of acute alcoholism rats and to explore the mechanism of the damage caused by ethanol to the neurons.@*METHODS@#The model of acute alcoholism rat was established by 50% alcohol gavage. The α-syn and caspase-3 were detected by immunohistochemical staining and imaging analysis at 1 h, 3 h, 6 h and 12 h after acute alcoholism. The number of positive cell and mean of optical density were detected and the trend change was analyzed. The variance analysis and t-test were also performed.@*RESULTS@#The number of α-syn positive cell and average optical density in brain cortex of acute alcoholism rat increased significantly and peaked at 6 hour with a following slight decrease at 12 h, but still higher than the groups at 1 h and 3 h. Within 12 hours after poisoning, the number of caspase-3 positive cell and average optical density in brain cortex of rats gradually increased.@*CONCLUSIONS@#The abnormal aggregation of α-syn caused by brain edema and hypoxia may participate the early stage of neuronal apoptosis in brain cortex after acute alcoholism.

Hypobaric hypoxia-mediated protein expression in plasma of susceptible & tolerant rats.

Background & objectives: Low availability of oxygen at high altitudes has a great impact on the human life processes. There is a widespread interest and need to find out protein(s) that are possibly involved in mediating tolerance to hypobaric hypoxia. We undertook this study to identify and characterize protein expression in plasma of hypoxia susceptible and tolerant rats. Methods: Male albino Sprague Dawley rats were segregated into susceptible and tolerant groups on the basis of their gasping time when exposed to simulated hypobaric hypoxia of 32,000 ft (9,754 m) at 32ºC. Comparative proteome profiling of blood plasma of hypoxia susceptible and tolerant individuals was performed using 2-dimentional (2-D) gel electrophoresis. Results: Three proteins with higher expression levels were selected separately from tolerant and susceptible samples. Characterization of these proteins from tolerant sample using MALDI-TOF/TOF and MASCOT search indicated their homology with two different super-families viz. NADB-Rossmann superfamily (Rab GDP dissociation inhibitor β) and Transferrin superfamily (two Serotransferrins), having potential role in imparting tolerance against hypoxia. Three high level upregulated proteins were characterized from blood plasma of hypoxia susceptible animals showing similarity with threonine tRNA ligase (mitochondrial), carbohydrate sulphotransferase 7 and aspartate tRNA ligase (cytoplasmic) that play a role in ATP binding, carbohydrate metabolism and protein biosynthesis, respectively. Interpretation & conclusions: Our results indicated that rats segregated into hypoxia sensitive and tolerant based on their gasping time showed differential expression of proteins in blood plasma. Characterization of these differentially expressed proteins will lead to better understanding of molecular responses occurring during hypoxia and subsequently development of biomarkers for categorization of hypoxia susceptible and tolerant individuals.

Hypoxia/reoxygenation-induced myocardial lesions in newborn piglets are related to interindividual variability and not to oxygen concentration

OBJECTIVE: Evaluation of myocardial histological changes in an experimental animal model of neonatal hypoxiareoxygenation. METHODS: Normocapnic hypoxia was induced in 40 male Landrace/Large White piglets. Reoxygenation was initiated when the animals developed bradycardia (HR <60 beats/min) or severe hypotension (MAP <15 mmHg). The animals were divided into four groups based on the oxygen (O2) concentration used for reoxygenation; groups 1, 2, 3, and 4 received 18%, 21%, 40%, and 100% O2, respectively. The animals were further classified into five groups based on the time required for reoxygenation: A: fast recovery (<15 min); B: medium recovery (15-45 min); C: slow recovery (45-90 min); D: very slow recovery (>90 min), and E: nine deceased piglets. RESULTS: Histology revealed changes in all heart specimens. Interstitial edema, a wavy arrangement, hypereosinophilia and coagulative necrosis of cardiomyocytes were observed frequently. No differences in the incidence of changes were observed among groups 1-4, whereas marked differences regarding the frequency and the degree of changes were found among groups A-E. Coagulative necrosis was correlated with increased recovery time: this condition was detected post-asphyxia in 14%, 57%, and 100% of piglets with fast, medium, and slow or very slow recovery rates, respectively. CONCLUSIONS: The significant myocardial histological changes observed suggest that this experimental model might be a reliable model for investigating human neonatal cardiac hypoxia-related injury. No correlation was observed between the severity of histological changes and the fiO2 used during reoxygenation. Severe myocardial changes correlated strictly with recovery time, suggesting an unreported individual susceptibility of myocardiocytes to hypoxia, possibly leading to death after the typical time-sequence of events.

Vertebral column deformity and hypoxia in Salmo salar / Hipoxia relacionada a deformidad de columna vertebral en Salmo salar

Vertebral Column Deformity (VCD) is a common pathology in Chilean salmon farms, lowering the quality and commercialization of the product. Hypoxia has been related to other musculoskeletal deformities, but not to VCD. This work analyzes the morphology of the vertebral column of Salmo salar alevins, cultured under hypoxic conditions (60 percent O2 saturation in the water tanks) for different time periods after hatching (2, 4, 6 and 8 days). They are compared with their normoxic controls (100 percent O2 saturation). Using histological (H/E), and morphometric techniques, it was found that the time of exposure to hypoxia is inversely proportional to the body length, notochordal diameter and thickness of its sheath. The organic response to hypoxia was quantified by immunohistochemistry for HIF-1a as the sensor of hypoxia. Its expression increased significantly (p<0.05) in the experimental groups that exhibit VCD. Although etiology for VCD is probably multifactorial, this study allows for the conclusion that hypoxia by itself, produces VCD.

La deformidad de columna vertebral (DCV) es una patología que se presenta frecuentemente en la salmonicultura chilena, disminuyendo la calidad y comercialización del producto. La hipoxia ha sido relacionada a otras deformidades musculoesqueléticas pero no a DCV. Este trabajo analiza la morfología de la columna vertebral en alevines Salmo salar cultivados en condiciones de hipoxia (60 por ciento de saturación de O2) en diferentes momentos después de la eclosión (2, 4, 6 y 8 días) y son comparados con sus respectivos controles en normóxia (100 por ciento de saturación de O2). Utilizando técnica histológica (H/E) y morfométrica, se determinó que el tiempo de exposición a hipoxia es inversamente proporcional a la longitud corporal, diámetro notocordal y grosor de su vaina. La respuesta orgánica a hipoxia fue cuantificada mediante inmunohistoquímica contra HIF-1a como censor de hipoxia. Su expresión incrementó significativamente (p<0,05) en los grupos experimentales que presentaron DCV. Aunque la etiología de DCV es probablemente multifactorial, este estudio permite concluir que la exposición a hipoxia puede provocar DCV por sí sola.

Participación del óxido nítrico, proteína Fos y el tallo cerebral en la retención de glucosa encefálica durante la hipoxia / Involvement of the nitric oxide, Fos protein and brain stem in the retention of brain glucose during hypoxia

Se ha descrito que el núcleo del tracto solitario (NTS), estructura del tallo cerebral y vía de relevo de las aferencias del los quimiorreceptores del senocuerpo carotídeo (RSCC), participa en el aumento en la retención de glucosa por el cerebro (RGC) ante una hipoxia. Es probable que en esta respuesta participe el óxido nítrico (NO) y la proteína Fos. En este trabajo se analiza el papel del NO en el NTS sobre la modificación de la RGC y la expresión de la proteína inmunorreactiva Fos (Fos-ir) en ratas in vivo. La inyección de un donador del NO como es el nitroprusiato de sodio (NPS) en el NTS, 4 min antes de la estimulación de los RSCC, disminuyó la RGC, pero incrementó la expresión de Fos-ir en un mayor número de neuronas en el NTS con respecto a las ratas control, que sólo recibieron líquido cefalorraquídeo artificial (LCRa) antes de la estimulación RSCC. En contraste, un inhibidor selectivo del NO como el N?-nitro-L-arginina metil éster (L-NAME) en el NTS 4 min antes de la estimulación RSCC con NaCN, aumentó la RGC, pero disminuyó el número de neuronas Fos-ir comparados con el control o con NPS. La detección inmunohistoquímica de la expresión de Fos-ir en las células del tallo cerebral indica que la estimulación RSCC activa vías dependientes de NO en el NTS, para regular la RGC. El estudio de esta población de células en el NTS, serß importante para definir su caracterización.

It has been said that the nucleus tractus solitarii (NTS), one structure of the brain stem and path of apherences of chemoreceptors of carotid sinus-body, is involved in the increased glucose retention by the brain in case of hypoxia. It is likely that nitric oxide and Fos protein also take part in this response. This paper analyzes the role of nitric oxide in the NTS on the change of glucose retention by the brain and the expression of inmunoreactive protein Fos (ir-Fos) in rats in vivo. The injection of a NO donor such as sodium nitroprusiate in the NTS four minutes before the stimulation of carotid sinus-body chemoreceptors decreased glucose retention by the brain but increased the expression of ir-Fos in a higher number of neurons in NTS with respect to control group rats which only received artificial cerebrospinal fluid before the stimulation. In contrast, the use of a selective NO inhibitor such as NO-nitro-L-arginine methyl ester (L-NAME) in the NTS four minutes before the stimulation of the chemoreceptors with NaCN, increased the glucose retention by the brain but reduced the number of neurons with ir-Fos expression when compared with the control group or the sodium nitroprusiate injection. The immunohistochemical detection of ir-Fos expression in the brain stem cells indicated that stimulation of carotid sinus-body chemoreceptors activated NO-dependent paths in the NTS to regulate glucose retention by the brain. The study of this cell population in the NTS will be important to define its characterization.

Evaluation of lung infiltration score to predict postural hypoxemia in ventilated acute respiratory distress syndrome patients and the lateralization of skin pressure sore.

Context: Mechanical ventilation with positive end expiratory pressure (PEEP) is associated with unequal aeration of lungs in acute respiratory distress syndrome (ARDS) patients. Therefore, patients may develop asymmetric atelectasis and postural hypoxemia during lateral positioning. Aims: To validate proposed lung infiltration score (LIS) based on chest x-ray to predict postural hypoxemia and lateralization of skin sores in ARDS patients. Settings and Design: University hospital ICU. Prospective, observational study of consecutive patients. Materials and Methods: Sixteen adult patients of both genders on mechanical ventilation with PEEP for 24 to <48 hours. On chest x-ray, 6 segments were identified on each lung. The proposed LIS points (0- normal; 1- patchy infiltrates; 2- white infiltrates matching heart shadow) were assigned to each segment. Without changing ventilation parameters, supine, left and right lateral positions at 45° tilt were randomly changed. At the end of 20 minutes of ventilation in each position, we observed arterial oxygen saturation, hemodynamic and arterial blood gases. Later, position change protocol (4 hourly) was practiced in ICU, and skin pressure sore grading was noted within a week of ICU stay. Statistical Analysis Used: Nonparametric Bland and Altman correlation analysis, ANOVA and Student t test. Results: Arterial oxygenation (PaO 2 /FiO 2 = 313± 145.6) was significantly (P<0.01) higher in better lung (lower LIS)-down position than supine (PaO 2 /FiO 2 = 199± 70.2) or a better lung-up position (PaO 2 /FiO 2 = 165± 64.8). The positioning-related arterial oxygenation was significant (P< 0.05) at LIS asymmetry ≥3 between two lungs. Conclusions: The LIS mapping on chest x-ray was useful to differentiate between asymmetric lung disease and postural hypoxemia in ICU patients, which predisposed patients to early skin sore changes on higher LIS side.

Cambios ultraestructurales del trofoblasto en los casos de hipoxia durante la preeclampsia / Ultraestructural changes of trophoblast in hipoxic cases during

Examinar la ultraestructura del sincitiotrofoblasto en placentas de embarazadas complicadas con preeclampsia con especial referencia al efecto de la hipoxia sobre la estructura fina del tejido. Diez placentas, a término, afectadas por preeclampsia, fueron tomadas inmediatamente después del parto por cesárea y de cada una de ellas tres biopsias de la superficie maternal se disecaron en sala de parto, en especímenes de 2 a 5 mm, y se fijaron por inmersión en glutaraldehido al 4 por ciento, pH 7,4,a 4 ºC. Posteriormente se dividieron en fragmentos de 1 mm y sumergidos en solución fresca fijadora por períodos variables de 2 a 72 horas seguidas por una fijación secundaria en tetraóxido de osmio al 1 por ciento en buffer fosfato 0,1 M durante 1 hora. Las muestras se procesaron siguiendo los procedimientos convencionales de a microscopia electrónica de transmisión para su observación. Laboratorio de microscopia electrónica del Ciadana, Facultad de Ciencias de la Salud, Maracay. Los hallazgos revelan proyecciones de la membrana plasmática del sincitio de diversas formas, que simulan desprenderse de la superficie. La membrana basal del sincitio se mostró engrosada. Mitocondrias en diversos grados de degeneración presentaron partículas electron densas en la matriz mitocondrial. Regiones apicales del citoplasma sincitial parecen desprenderse hacia el espacio intervelloso. Numerosas vacuolas intracitoplasmáticas y ampliaciones de las cisternas del retículo endoplásmico rugoso se destacan en el citoplasma. Interrupciones de la membrana sincitial y regiones citoplásmicas sin membrana plasmática se notaron. Fragmentos del sincitio desprendidos de la superficie del mismo sugieren ser los corpúsculos que dañan los endotelios de la unidad materna – feto – placentaria constituyendo uno de los estímulos para l mantenimiento de a patogénesis de a preeclampsia.

Avaliação de um modelo experimental de enterocolite necrosante neonatal em ratos / Evaluation of an experimental model of necrotizing enterocolitis in rats

OBJETIVO: Avaliar um modelo experimental de enterocolite necrosante em ratos proposto por Okur e colaboradores em 1995. MÉTODOS: Utilizou-se 28 ratos da raça EPM-Wistar no primeiro dia de vida, com peso entre 4 a 6 gramas. Os animais foram submetidos a hipóxia (H) colocando os filhotes em uma câmara de gás CO2 para sacrifício de roedores onde receberam um fluxo de ar contendo 100 por cento de CO2 durante 5 minutos. Após a hipóxia os animais foram reanimados (R) com fluxo de ar contendo O2 a 100 por cento, também durante 5 minutos. Os animais divididos em dois grupos: G1: controle (n=12): ratos não submetidos a H-R; G2: (n=16): ratos submetidos a H-R. Segmentos de intestino delgado e cólon foram preparados para análise histológica. O restante do intestino foi utilizado para dosagem de malondialdeído tecidual. RESULTADOS: Dosagem de malondialdeído do G1 foi em média 1,05 (0,44-2,03) e do G2 foi em média 2,60 (0,59- 6,4) nmol MDA/mg proteína. O G2 teve média significativamente maior do que a do grupo controle (p<0,002). Foi encontrada diferença estatisticamente significante entre os grupos de estudo quanto à distribuição do grau de lesão onde o grupo G1 apresentou graus significantemente menores do que o grupo G2. CONCLUSÕES: O modelo mostrou que a hipóxia neonatal em ratos provoca lesões na parede intestinal.. Apesar das lesões histológicas discretas é um bom método para avaliação da liberação de radicais livres teciduais.

Hipoxemia pre-operatoria: indicador de complicaciones pulmonares post-operatorias en cirugías de abdomen superior / Hypoxemia pre-operatory: indicator of pulmonary complications post-operatory in superior abdomen surgerys

Las Cirugias de Abdomen Superior (CAS) desencadenan cambios importantes en la función pulmonar, fundamentalmente descenso de la capacidad vital y capacidad residual funcional, alteraciones que son paralelas a la disminución de la presión arterial de oxigeno (PaO2), pudiendo ser tan marcados que ocasionan atelectasia y por ende, riesgo de infección. Se realizó un ensayo clínico descriptivo de 50 pacientes mayores de 30 años con patología quirúrgica abdominal alta, 24 formaron el grupo hipoxémico (PaO2 menor a la esperada para la edad) y 26 el grupo normal, para determinar si la hipoxemia preoperatoria era indicador de complicaciones pulmonares post-operatorias /CPPO) en CAS y qué factores de riesgo se asocian con la hipoxemia. Seis pacientes presentaron CPPO en las primeras 24 horas, 4 pertenecian al grupo hipoxémico, no encontrándose diferencia estadisticamente significativa entre los grupos (p=0.2953); los factores de riesgo evaluados no mostraron asociación con la hipoxemia (p > 0.05)

Biological basis of chronic mountain sikness / Bases biológicas del mal de montaña crónico

Los Andes completaron su elevación actual hace 18 millones de años cuando los mamíferos ya se habían expandido por el nivel del mar 65 millones de años atrás. Por lo tanto, los mamíferos son invasores recientes de los Andes. Los andinos son recién llegados a la altura con sólo miles de años de exposición a la hipoxia. El mal de montaña crónico constituye una respuesta exagerada de los mecanismos fisiológicos que aparecen en el curso de la aclimatización de los recién llegados a la altura o en los nativos de la altura, que eventualmente conduce a sítomas de intolerencia al medio hipóxico. Hay una total pérdida de la hiperventilación con PaO2 de 40 torr en nativos de la altura con excesiva policitemia y sítomas de mal de montaña crónico comparado con 32 torr en los sujetos jóvenes asintomáticos (hipoventilación excesiva). Cerca del 33 por ciento de la población de Cerro de Pasco (4340 m) mayores de 50 años tienen concentraciones de hemoglobina por encima de 21.3 g/dl. En el mal de montaña crónico se observa un aumento exagerado de la hipertensión arterial pulmonar, agrandamiento de los cuerpos carotídeos en nativos de la altura y una alta incidencia de quemodectomas.

Las arterias pulmonares distales en los habitantes de las alturas / The pulmonary distal arteries at high altitude population

El estudio de las arterias pulmonares, en el hombre y en los animales que viven en las grandes alturas, ha demostrado la existencia de varios cambios morfológicos, como la muscularización de las arteriolas así como la proliferación de células musculares lisas en la íntima de las arterias distales. Estos cambios están relacionados con una vasoconstricción como respuesta a la hipoxia y al desarrollo de una hipertensión arterial pulmonar que, en algunos casos, se asocian con hipertrofia ventricular derecha e insuficiencia cardiaca congestiva, como en la enfermedad subaguda de la altura, descrita en el Himalaya y en los Andes en el hombre y en ciertas especies animales. Una posible pérdida de la respuesta vasoconstrictiva por transmisión genética a la hipoxia crónica se ha observado como una aclimatización o adaptación a las grandes alturas.