Marcos Eugênio Soares Duarte

Adult derived mononuclear bone marrow cells improve survival in a model of acetaminophen-induced acute liver failure in rats

INTRODUCTION Acute liver failure (ALF) is characterized by a rapid loss of hepatic function, with high mortality. Acetaminophen (APAP) intoxication and viral hepatitis are common causes of ALF. Several studies have shown the capacity of adult bone marrow cells to differentiate in hepatocytes, suggesting their use for treating ALF. AIM In the present study, we tested the use of adult derived mononuclear bone marrow fraction to improve the survival of Wistar rats with APAP-induced ALF. METHODS Forty-eight female Wistar rats pre-induced with phenobarbital were given APAP in a single dose of 1g/kg via intraperitoneal injection. Bone marrow mononuclear cells were purified from male rats using FICOLL gradient and injected through the portal vein in a volume of 0.2mL containing 1x10(6) cells stained with DAPI. Treatment was administered 24h after APAP injection. The sham group (n=24), received 0.2mL of saline through the portal vein 24h after APAP administration. Survival, liver histology and ALT levels were observed. RESULTS Survival 72h post-APAP administration was 33% in the sham group and 70.8% in the group receiving bone marrow cells. Liver histology in treated animals showed less intense necrosis and the presence of DAPI-positive cells. CONCLUSIONS We have shown that bone marrow derived cells are capable of significantly increasing the survival rate of APAP-induced ALF in 37.5% (95% CI, 27.8-40.3%).

Distortion product otoacoustic emissions in sheep before and after hyperinsulinemia induction

UNLABELLED Transient evoked otoacoustic emissions and distortion product otoacoustic emissions have gained significant importance in the identification of cochlear alterations. AIM To record distortion product thresholds through the monitoring of otoacoustic emissions in normal conditions and in the presence of electrophysiologic changes in cochlear outer hair cells in sheep after hyperinsulinemia induction. MATERIAL AND METHODS Experimental study, with seven sheep in the control group and seven in the study group. Insulin and glucose concentrations were measured simultaneously for the recording of distortion product otoacoustic emission every 10 minutes, all the way to 90 minutes. The control group received saline solution, and the study group received a bolus injection of 0.1 U/kg of regular human insulin. RESULTS There was a significant reduction in distortion product thresholds in the study group when compared to the control group at frequencies greater than 1,500 Hz and after 60 minutes (P < 0.001). CONCLUSION This study established distortion product otoacoustic emission thresholds in sheep with constant reproducibility, demonstrating that the method is adequate for use in audiology and otology investigations. Results also fully confirm that acute hyperinsulinemia may cause important changes in these thresholds.

Emissões otoacústicas por produtos de distorção em ovinos normais e após indução de hiperinsulinemia

As emissoes otoacusticas transientes evocadas e as emissoes otoacusticas por produtos de distorcao vem assumindo importância significativa na identificacao de alteracoes cocleares. OBJETIVO: Atraves da monitorizacao das emissoes otoacusticas, registrar os limiares dos produtos de distorcao em condicoes normais e na presenca de modificacoes eletrofisiologicas nas celulas ciliadas externas cocleares de ovelhas apos a inducao de hiperinsulinemia aguda. MATERIAL E METODO: Estudo experimental com sete ovelhas no grupo-controle e sete no grupo-estudo. Os niveis de insulina e glicose foram verificados simultaneamente ao registro das emissoes otoacusticas por produtos de distorcao de 10 em 10 minutos, ate o tempo de 90 minutos. O grupo-controle recebeu soro fisiologico, e o grupo-estudo, injecao em bolo de 0,1 U/kg de insulina humana regular. RESULTADOS: Houve diminuicao significante nos limiares dos produtos de distorcao no grupo-estudo em relacao ao grupo-controle nas frequencias acima de 1.500 Hz e apos o tempo de 60 minutos (P < 0,001). CONCLUSAO: O estudo permitiu estabelecer os limiares das emissoes otoacusticas por produtos de distorcao em ovelhas com constante reprodutibilidade, o que mostra que o metodo e adequado para uso em investigacoes audiologicas e otologicas. Ficou, ainda, plenamente identificado que o hiperinsulinismo agudo foi capaz de provocar relevantes modificacoes nestes limiares.

Gastric Yield Pressure and Gastric Yield Volume to Assess Anti-Reflux Barrier in a Porcine Model

ABSTRACT Anti-reflux barrier (ARB) resistance may be useful to test new treatments for gastroesophageal reflux (GER). The ARB has been estimated by increasing gastric yield pressure (GYP) and gastric yield volume (GYV) in animal models but has not been validated. This study aimed to develop an experimental model suitable for assessing the ARB resistance to increasing intragastric pressure and volume and its reproducibility in a seven-day interval. Ten two-month-old female Large-White swine were studied. Intragastric pressure and volume were recorded using a digital system connected to a Foley catheter inserted through gastrostomy into the stomach. GYP and GYV were defined as the gastric pressure and volume able to yield gastric contents into the esophagus detected by esophageal pH. A sudden pH drop below 3 sustained during 5 min was considered diagnostic for gastric yield. Animals were studied again after seven days. On days 0 and 7, there were no significant differences for GYP (mean ± SD = 7.66 ± 3.02 mmHg vs. 7.07 ± 3.54 mmHg, p = .686) and GYV (636.70 ± 216.74 ml vs. 608.30 ± 276.66 ml; p = .299), respectively. Concordance correlation coefficient (ρc) was significant for GYP (ρc = 0.634, 95% CI = 0.141–0.829, p = .006), but not for GYV (ρc = 0.291, 95% CI = −0.118 to 0.774, p = .196). This study demonstrated an experimental model, assessing the ARB resistance. GYP seems to be a more reliable parameter than GYV for assessment of ARB resistance.