RESUMO A utilização da gema de ovo dificulta a padronização de meios diluidores e apresenta riscos biológicos. Assim, este estudo avaliou diferentes concentrações da lipoproteína de baixa densidade (LDL), em substituição à gema de ovo, para a confecção de diluentes para criopreservação espermática em ovinos. Foram utilizados um diluidor controle (CTR= 20% de gema de ovo) e cinco tratamentos, substituindo-se a gema pelas diferentes proporções de LDL (T1=6%; T2=8%; T3=12%; T4=16%; T5=20%), todos à base de TRIS-glicerol. Para o estudo, utilizaram-se dois ejaculados, de seis reprodutores da raça Santa Inês. Sessenta dias após a criopreservação, as amostras foram descongeladas e avaliadas subjetivamente quanto à motilidade total (MT, %) e progressiva (MP, %), ao vigor (1-5) e à integridade funcional (choque hisposmótico com água destilada, %) e estrutural (corante supravital eosina, %) das membranas espermáticas. As avaliações de vigor e funcionalidade de membrana não diferiram (P>0,05) entre os grupos. Entretanto, os grupos T4 (P<0,01) e T5 (P<0,05) foram superiores ao CTR para os parâmetros MT, MP e integridade estrutural de membrana, o que confirma que as LDLs podem ser alternativas eficientes para substituição da gema de ovo em diluidores para criopreservação de sêmen ovino.

ABSTRACT The use of egg yolk makes it difficult to standardize extenders and presents biological hazards. Thus, this study evaluated different concentrations of low-density lipoprotein (LDL) to replace yolk extenders for production of sperm for cryopreservation in ovine. A control extender was used (CTR= 20% yolk) and five treatments, replacing the yolk by different ratios of LDL (T1= 6%; T2= 8%, T3= 12%; T4= 16%; T5= 20%) all based on TRIS-glycerol. For the study, two ejaculates from six Santa Ines breeding were used. Sixty days after cryopreservation, the samples were thawed and evaluated for total motility (MT, %) and progressive motility (MP, %), vigor (1-5) and the functional integrity (hyposmotic shock with distilled water, %) and structural (supravital dye eosin, %) of the sperm membranes. The evaluations of strength and membrane functionality didn’t differ (P> 0.05) between groups. However, T4 (P< 0.01) and T5 (P< 0.05) groups were superior to the CTR for the MT, MP, and membrane structural integrity parameters, which confirms that LDLs can be efficient alternatives for yolk replacement in extenders for cryopreservation of ovine semen.

Estimates of occult hepatitis B virus (HBV) infection prevalence varies among different studies depending on the prevalence of HBV infection in the study population and on the sensitivity of the assay used to detect HBV DNA. We investigated the prevalence of occult HBV infection in cirrhotic patients undergoing liver transplantation in a Brazilian referral center. Frozen liver samples from 68 adults were analyzed using a nested polymerase chain reaction assay for HBV DNA. The specificity of the amplified HBV sequences was confirmed by direct sequencing of the amplicons. The patient population comprised 49 (72.1%) males and 19 (27.9%) females with a median age of 53 years (range=18-67 years). Occult HBV infection was diagnosed in three (4.4%) patients. The etiologies of the underlying chronic liver disease in these cases were alcohol abuse, HBV infection, and cryptogenic cirrhosis. Two of the patients with cryptic HBV infection also presented hepatocellular carcinoma. Markers of previous HBV infection were available in two patients with occult HBV infection and were negative in both. In conclusion, using a sensitive nested polymerase chain reaction assay to detect HBV DNA in frozen liver tissue, we found a low prevalence of occult HBV infection in cirrhotic patients undergoing liver transplant, probably due to the low prevalence of HBV infection in our population.

The gut barrier monitors and protects the gastrointestinal tract from challenges such as microorganisms, toxins and proteins that could act as antigens. There is evidence that gut barrier dysfunction may act as a primary disease mechanism in intestinal disorders. The aim of the present study was to evaluate the barrier function towards sugars after the appropriate treatment of celiac disease and Crohn's disease patients and compare the results with those obtained with healthy subjects. Fifteen healthy volunteers, 22 celiac disease patients after 1 year of a gluten-free diet, and 31 Crohn's disease patients in remission were submitted to an intestinal permeability test with 6.0 g lactulose and 3.0 g mannitol. Six-hour urinary lactulose excretion in Crohn's disease patients was significantly higher than in both celiac disease patients (0.42 vs 0.15%) and healthy controls (0.42 vs 0.07%). Urinary lactulose excretion was significantly higher in celiac disease patients than in healthy controls (0.15 vs 0.07%). Urinary mannitol excretion in Crohn's disease patients was the same as healthy controls (21 vs 21%) and these values were significantly higher than in celiac disease patients (10.9%). The lactulose/mannitol ratio was significantly higher in Crohn's disease patients in comparison to celiac disease patients (0.021 vs 0.013) and healthy controls (0.021 vs 0.003) and this ratio was also significantly higher in celiac disease patients compared to healthy controls (0.013 vs 0.003). In spite of treatment, differences in sugar permeability were observed in both disease groups. These differences in the behavior of the sugar probes probably reflect different mechanisms for the alterations of intestinal permeability.

The present study examined the in vitro and in vivo development of bovine nuclear-transferred embryos. A bovine fetal fibroblast culture was established and used as nucleus donor. Slaughterhouse oocytes were matured in vitro for 18 h before enucleation. Enucleated oocytes were fused with fetal fibroblasts with an electric stimulus and treated with cytochalasin D and cycloheximide for 1 h followed by cycloheximide alone for 4 h. Reconstructed embryos were cultured for 7-9 days and those which developed to blastocysts were transferred to recipient cows. Of 191 enucleated oocytes, 83 (43.5%) were successfully fused and 24 (28.9%) developed to blastocysts. Eighteen freshly cloned blastocysts were transferred to 14 recipients, 5 (27.8%) of which were pregnant on day 35 and 3 (16.7%) on day 90. Of the three cows that reached the third trimester, one recipient died of hydrallantois 2 months before term, one aborted fetus was recovered at 8 months of gestation, and one delivered by cesarian section a healthy cloned calf. Today, the cloned calf is 15 months old and presents normal body development (378 kg) and sexual behavior (libido and semen characteristics).