Quantitative differences in lipid raft components between murine CD4<Superscript>+</Superscript> and CD8<Superscript>+</Superscript> T cells

Background  

Lipid rafts have been shown to play a role in T cell maturation, activation as well as in the formation of immunological synapses in CD4⁺ helper and CD8⁺ cytotoxic T cells. However, the differential expression of lipid raft components between CD4⁺ and CD8⁺ T cells is still poorly defined. To examine this question, we analyzed the expression of GM1 in T cells from young and aged mice as well as the expression of the glycosylphosphatidylinositol (GPI)-linked protein Thy-1 and cholesterol in murine CD4⁺ and CD8⁺ T cell subpopulations.     

Autoreactivity to self H-2Kb peptides in TAP1 mice. Intravenous administration of H-2Kb class I-derived peptides induces long-term survival of grafts from C57BL/6 donors

We and others have previously shown that TAP1-/- mice (H-2b) reject grafts from donors without major histocompatibility complex (MHC) disparity that express wild-type levels of H-2b class I molecules (C57BL/6, TAP1+/+ mice). In this same model, we also showed that subcutaneous priming of TAP1-/- mice with synthetic peptides derived from the H-2Kb molecule accelerated graft rejection and that in vivo depletion of CD4+ T cells induced a significant prolongation of graft survival, suggesting an important role for CD4 T cells. We hypothesize that, in this model, rejection is triggered by the recognition of class I molecules or derived peptides, in an inflammatory microenvironment, by a functionally altered autoreactive T-cell repertoire that escapes the control of peripheral regulatory mechanisms. In the present study, we analysed the cellular autoreactivity induced by synthetic peptides derived from the H-2Kb sequence in naive and TAP1-/- mice transplanted with C57BL/6 grafts, and investigated whether intravenous modulation of autoreactivity to these peptides induced transplantation tolerance. We showed that TAP1-/- mice have peripheral autoreactive T cells that recognize H-2Kb peptides. A significant amplification of proliferation against these peptides was detected in TAP1-/- mice that rejected grafts, indicating that the inflammatory context of transplantation induced peripheral expansion of these autoreactive T cells. Furthermore, intravenous injection of H-2Kb-derived peptides significantly prolonged graft survival in some animals. In these mice (> 100 days graft survival), we observed intragraft inhibition of interferon-gamma and interleukin-10 expression, suggesting that these cytokines have an active role during the rejection. In conclusion, our present data indicate that inflammatory autoreactive T cells directed against H-2Kb peptides can be inhibited in the periphery to prolong graft survival in TAP1-/- mice.     

Atypical copy number abnormalities in 22q11.2 region: Report of three cases

The 22q11.2 Deletion Syndrome (22q11.2DS) is the most common microdeletion syndrome in humans, with a highly variable phenotype. This chromosomal region contains low copy repeat (LCR) sequences that mediate non-allelic homologous recombination which predispose to copy number abnormalities at this locus. This article describes three patients investigated for suspicion of 22q11.2DS presenting atypical copy number abnormalities overlapping or not with the common ～3 Mb deletion. They were investigated by G-banding karyotype, Multiplex-ligation dependent probe amplification (MLPA) and array Genomic Hibridization (aGH). Clinical and molecular data were compared with literature, in order to contribute to genotype–phenotype correlation. Atypical chromosomal abnormalities were detected: 3.6 Mb deletion at 22q11.21-q11.23 between LCRs B–F in patient 1 and approximately 1.5 Mb deletion at 22q11.21-q11.22 between LCRs D–E in patients 2 and 3. The breakpoints detected in patient 1 have not been previously described. These findings exemplify the complexity and genetic heterogeneity observed in 22q11.2 region and corroborates the idea that genetic modifiers contribute to the phenotypic variability observed in proximal and distal 22q11.2 deletion syndromes.     

Quantitative nucleic acid sequence-based assay as a new molecular tool for detection and quantification of Leishmania parasites in skin biopsy samples

Currently available methods for the diagnosis of cutaneous leishmaniasis (CL) have low sensitivities or are unable to quantify the number of viable parasites. This constitutes a major obstacle for the diagnosis of the disease and for the study of the effectiveness of treatment schedules and urges the development of improved detection methods. In this study, quantitative nucleic acid sequence-based amplification (QT-NASBA) technology was used to detect and quantify Leishmania parasites in skin biopsy samples from CL patients. The assay is based on the detection of a small subunit rRNA (18S rRNA), which may allow for the detection of viable parasites. The QT-NASBA assay was evaluated using in vitro-cultured promastigotes and amastigotes and 2-mm skin biopsy samples from Old and New World CL patients. The study demonstrated that the lower detection limit of the QT-NASBA was two parasites per biopsy sample. Parasites could be quantified in a range of 2 to 11,300,000 parasites per biopsy sample. The QT-NASBA could detect levels of parasites 100-fold lower than those detected by conventional PCR. Test evaluation revealed that the QT-NASBA had a sensitivity of 97.5% and a specificity of 100% in the present study. The QT-NASBA is a highly sensitive and specific method that allows quantification of both Old and New World Leishmania parasites in skin biopsy samples and may provide an important tool for diagnosis as well as for monitoring the therapy of CL patients.     

A simple intra-operative maneuver to decrease a duodenal ulcer hemorrhage temporarily: description and anatomical bases

Intraoperative hemostatic suture to treat a bleeding duodenal ulcer is sometimes difficult when there is massive hemorrhage. The aims of this paper are: (1) to describe a practical and easy intraoperative procedure which quickly decreases a massively bleeding duodenal ulcer, allowing the surgeon to identify the bleeding site clearly and obtain definitive hemostasis by suturing the involved vessels with a low risk of common bile duct lesion; and (2) to study in cadavers the anatomical basis of this surgical procedure already successfully performed on patients. Fourteen patients with massive duodenal ulcer bleeding, after unsuccessful endoscopic hemostasis, were operated on and included in this study. After surgical anterior gastroduodenotomy, the surgeon introduced a finger in a downward and forward direction in the bursa omentalis vestibule through the omental foramen. This simple and quick procedure decreased hemorrhage by compressing the gastroduodenal artery against the first part of the posterior surface of the duodenum. Twenty-four fresh blocks of normal tissue were removed from cadavers and were injected with silicone rubber through the common hepatic artery. The distance between the gastroduodenal artery and the omental foramen was measured. With this maneuver the surgeon can clearly see the exact bleeding site and perform an adequate suture with a minor risk of common bile duct lesion.     

Impaired sustained attention and lapses are present in patients with mild obstructive sleep apnea

Sleep and Breathing - Severe obstructive sleep apnea (OSA) directly affects the quality of life, mood, and sustained attention of individuals, but it has not yet been established in the literature,...     

Antihypertensive agents have different ability to modulate arterial pressure and heart rate variability in 2K1C rats

We examined the effect of chronic (15 days) administration of antihypertensive agents, from different pharmacologic classes, on arterial pressure (AP) and heart rate variability in two-kidney, one-clip hypertensive (2K1C) rats. The 2K1C rats received by gavage one of the following: water, ramipril, losartan, atenolol, amlodipine, or hydrochlorothiazide. Sham-operated normotensive rats received water. After 15 days of treatment AP was continuously sampled from an indwelling catheter in awake rats during a 2-h period and systolic AP and pulse interval (PI) were submitted to autoregressive spectral analysis with oscillatory components quantified in low (LF: 0.25 to 0.75 Hz) and high (HF: 0.75 to 3.0 Hz) frequency bands. The AP measured by tail-cuff was 170 +/- 2 mm Hg in 2K1C and 131 +/- 3 mm Hg in normotensive rats. Pooled data indicated that all antihypertensive agents reduced the AP of 2K1C rats to 127 +/- 2 mm Hg, whereas 2K1C rats treated with water remained hypertensive (206 +/- 11 mm Hg). Variance of systolic AP was found increased in 2K1C rats treated with water (34 +/- 2 mm Hg2), whereas 2K1C rats treated with ramipril, atenolol, amlodipine, or hydrochlorothiazide presented AP variance similar to normotensive rats (16 +/- 2 mm Hg2). Losartan normalized AP of 2K1C rats but variance of systolic AP remained increased (34 +/- 7 mm Hg2). The 2K1C rats treated with water had increased LF of systolic AP, whereas 2K1C rats treated with losartan showed higher LF of systolic AP and PI. Atenolol presented lower LF and higher HF of PI. In conclusion, losartan normalized AP but did not reduce AP variability, suggesting an autonomic imbalance characterized by higher sympathetic modulation of the cardiovascular system.