DNA damage and aging on hematopoietic stem cells: Impact of oxidative stress in ApoE-/- mice.

The effects of aging on ROS production and DNA damage were assessed in hematopoietic stem cells (HSCs) from apolipoprotein E-deficient (ApoE-/-) mice (2-, 12- and 24-month-old), a traditional experimental model of atherogenic dyslipidemia. HSCs from aged ApoE-/- mice were associated with increased ROS levels, leading to loss quiescence, DNA damage, apoptosis and telomere shortening. The concurrence of lack of ApoE and aging result in exhaustion and senescence of HSCs accompanied by increased oxidative stress and inflammation. Therefore, our data open avenues to a better understanding of age-related changes and genetic factors, which may synergistically compromise the efficacy of aged HSC recovery and/or transplantation.

Occult hepatitis B virus infection among blood donors from the Brazilian Amazon: implications for transfusion policy.

BACKGROUND: Brazil requires the performance of both a test for hepatitis B surface antigen (HBsAg) and a test for antibodies to the core of hepatitis B for blood donor screening. Blood centres in regions of high HBV endemicity struggle to maintain adequate stocks in face of the high discard rates due to anti-HBc reactivity. We evaluated the potential infectivity of donations positive for anti-HBc in search of a rational approach for the handling of these collections. STUDY DESIGN AND METHODS: We tested anti-HBc reactive blood donations from the state of Amazonas for the presence of HBV DNA and for titres of anti-HBs. The study population consists of village-based donors from the interior of Amazonas state. RESULTS: Among 3600 donations, 799 were anti-HBc reactive (22·2%). We were able to perform real-time PCR for the HBV S gene on specimens from 291 of these donors. Eight of these samples were negative for HBsAg and positive for HBV DNA and were defined as occult B virus infections (2·7%). Six of those eight specimens had anti-HBs titres above 100 mIU/ml, indicating the concomitant presence of the virus with high antibody titres. CONCLUSION: A small proportion of anti-HBc reactive donors carry HBV DNA and anti-HBs testing is not useful for predicting viremia on them. This finding indicates the possibility of HBV transmission from asymptomatic donors, especially in areas of high HBV prevalence. Sensitive HBV DNA nucleic acid testing may provide another level of safety, allowing eventual use of anti-HBc reactive units in critical situations.

Intractable complex partial seizures associated with posterior cerebral artery giant aneurysm: a case report.

Giant aneurysms have rarely been reported in association with intractable complex partial seizures (CPS). We report a 30-year-old man with intractable CPS since age 18 years. Seizure onset was electrically localized to right temporal lobe. Preoperative neuroimaging studies showed a partially thrombosed giant aneurysm of the right posterior cerebral artery. Selective amygdalohippocampectomy and occlusion of the posterior cerebral artery did not cause deficits. The patient has been seizure-free for 15 months after operation. We review the relevant literature on aneurysms as a cause of epilepsy.

[Clinical manifestations in complex partial crisis of the temporal lobe: a video-electroencephalographic study]. / Manifestações clínicas de crises parciais complexas do lobo temporal: um estudo vídeo-eletrencefalográfico.

We analysed 27 complex partial seizures arising from the temporal lobes recorded on videotape simultaneously with the EEG emphasizing the motor manifestations specially dystonic posturing, ictal paresis and head and eye forced deviation (version). The temporal lobe origin of the seizures was based on the agreement of many scalp-sphenoidal or zygomatic interictal and ictal EEG recordings, CT and MRI findings, interictal and, in some patients, ictal SPECT studies. 8 patients had surgery. In 5 from 7 patients who had temporal lobectomy, mesial temporal sclerosis was the anatomopathological finding and in one patient who had selective amigdalohippocampectomy, hemosiderosis and gliosis probably due to bleeding of a posterior cerebral artery giant aneurysm was found. All patients have been seizure free after surgery. While dystonic posturing and ictal paresis, present in 18 seizures (66.6%), were excellent as lateralizing seizure signs, since they were always contralateral to the ictal onset, contralateral and ipsilateral versive head and eye movements were observed.

Radioiodination of human growth hormone with characterization and minimization of the commonly defined "damaged products".

The radioiodination and chromatographic purification of human growth hormone (hGH) has been studied in order to better define and control the so-called "preparation damage", which is often a cause of interferences, loss in specific activity and sensitivity, misclassification errors in radioligand assays, and a source of misinterpretation when the tracer is used in receptors or in vivo studies. A series of labelings and false labelings, with and without protein carrier in the buffer used for Sephadex purification, indicate that the "preparation damage" peak is made up of two components: aggregated 125I-hGH and BSA-carried radioactivity. The former can be minimized by the use of recently extracted non-lyophilized hGH, and the latter by enzymatic labeling. Both components can be better resolved, and thus eliminated, when Sephadex G-100 is employed rather than G-75.