Dexamethasone treatment modulates aquaporin-4 expression after intracerebral hemorrhage in rats

This study investigated whether dexamethasone (DEX) treatment could regulate the expression of aquaporin-4 (AQP4) in rats with intracerebral hemorrhage (ICH). The results demonstrated that DEX significantly reduced AQP4 mRNA level in the perihematomal area compared with control group, but it increased the level in the brain area surrounding the third ventricle at day 1 post-ICH. There was no difference in AQP4 protein levels between DEX group and control group at the two above-mentioned brain regions at day 1 after ICH. The changes in AQP4 protein induced by DEX were marked at day 3 following surgery and still lasted at day 5 post-ICH, which were accompanied by a reduction of brain edema. Our results demonstrated that the expression of AQP4 protein after ICH was region-specific, time-dependent, and also indicated that DEX-induced cerebral edema clearance was correlated with the regulation of AQP4 expression in different brain regions.     

Meiotic segregation analysis in spermatozoa of pericentric inversion carriers using fluorescence in-situ hybridization

BACKGROUND: Pericentric inversions are structural chromosomal abnormalities resulting from two breaks, one on either side of the centromere, within the same chromosome, followed by 180 degrees rotation and reunion of the inverted segment. They can perturb spermatogenesis and lead to the production of unbalanced gametes through the formation of an inversion loop. METHODS: We report here the analysis of the meiotic segregation in spermatozoa from six pericentric inversion carriers by multicolour fluorescence in-situ hybridization (FISH) and review the literature. RESULTS: The frequencies of the non-recombinant products (inversion or normal chromosomes) were 80% for the inv(20), 91.41% for the inv(12), 99.43% for the inv(2), 68.12% for the inv(1), 97% for the inv(8)(p12q21) and 60.94% for the inv(8)(p12q24.1). The meiotic segregation of 20 pericentric inversions (including ours) is now available. The frequency of unbalanced spermatozoa varies from 0 to 37.85%. The probability of a crossover within the inverted segment is affected by the chromosome and region involved, the length of the inverted segment and the location of the breakpoints. CONCLUSIONS: No recombinant chromosomes were produced when the inverted segment involved <30% of the chromosome length (independent of the size of the inverted segment). Between 30 and 50%, few recombinant chromosomes were produced, inducing a slightly increased risk of aneusomy of recombination in the offspring. The risk of aneusomy became very important when the inverted segment was >50% of the chromosome length. Studies on spermatozoa from inversion carriers help in the comprehension of the mechanisms of meiotic segregation. They should be integrated in the genetic exploration of the infertile men to give them a personalized risk assessment of unbalanced spermatozoa.     

Neural progenitor cell transplantation and imaging in a large animal model

To evaluate neural stem/progenitor cell (NPC) transplantation therapy in cat models of neurodegenerative diseases, we have isolated, expanded and characterized feline NPCs (fNPCs) from normal fetal cat brain. Feline NPCs responsive to both human epidermal growth factor (hEGF) and human fibroblast growth factor 2 (hFGF2) proliferated as neurospheres, which were able to differentiate to neurons and glial cells. The analysis of growth factors indicated that both hEGF and hFGF2 were required for proliferation of fNPCs. In contrast to the effect on human NPCs, human leukemia inhibitory factor (hLIF) enhanced differentiation of fNPCs. Expanded fNPCs were injected into the brains of normal adult cats. Immunohistochemical analysis showed that the majority of transplanted cells were located adjacent to the injection site and some fNPCs differentiated into neurons. The survival of transplanted fNPCs over time was monitored using non-invasive bioluminescent imaging technology. This study provided the first evidence of allotransplantation of fNPCs into feline CNS. Cats have heterogeneous genetic backgrounds and possess neurological diseases that closely resemble analogous human diseases. The characterization of fNPCs and exploration of non-invasive bioluminescent imaging to track transplanted cells in this study will allow evaluation of NPC transplantation therapy using feline models of human neurological diseases.     

A comprehensive in vitro investigation of a portable magnetic separator device for human blood detoxification

A portable magnetic separator device is being developed for a proposed magnetically based detoxification system. In this paper, the performance of this device was evaluated via preliminary in vitro flow experiments using simple fluids and a separator unit consisting of one tube and two metal wires, each at the top and bottom of the tube. The effects of the following factors were observed: mean flow velocity U(o) (0.14-45 cm s(-1)), magnetic field strength micro(o)H(o) (0.125-0.50 T), wire size R(w) (0.125, 0.250 and 0.500 mm), wire length L(w) (2, 5 and 10 cm), wire materials (nickel, stainless steel 304 and 430) and tube size (outer radius R(o) = 0.30 mm and inner radius R(i) = 0.25 mm; R(o) = 0.50 mm and R(i) = 0.375 mm; and R(o) = 2.0 mm and R(i) = 1.0 mm). Our observations showed that the experimental results fit well with the corresponding theoretical results from the model we previously developed at a low flow velocity area (for example, U(o) < or = 20 cm s(-1)), strong external magnetic field (for example, > or = 0.30 T) and long wire length (for example, L(w) = 10 cm). The experimental results also showed that more than 90% capture efficiency is indeed achievable under moderate systemic and operational conditions. Pressure drop measurements revealed that the device could work well under human physiological and clinical conditions, and sphere buildup would not have any considerable effect on the pressure drop of the device. The breakthrough experiments demonstrated that a lower flow rate V, higher applied magnetic field micro(o)H(o) and diluted sphere suspension, i.e. lower C(o), would delay the breakthrough. All the results indicate the promise of this portable magnetic separator device to efficiently in vivo sequestrate nano-/micro-spheres from blood flow in the future magnetically based detoxification system.     

Effect of pH and Metal Ions on the Decomposition Rate of <Emphasis Type="Italic">S</Emphasis>-nitrosocysteine

S-nitrosothiols (RSNOs) have many biological functions including platelet deactivation, immunosupression, neurotransmission, and host defense. Most of the functions are attributed to nitric oxide (NO) release during S-nitrosothiol decomposition. As the simplest biologically occurring S-nitrosothiol, S-nitrosocysteine (CySNO) has been widely used as an NO donor and has also been incorporated into biomedical polymers. Knowledge of the CySNO decomposition rate is important for assessing the impact of CySNO on various bioengineering applications or biological systems. In this work, spectrophotometer measurements of CySNO decomposition in the presence of metal ions showed that the decomposition rate is highly susceptible to the pH. The maximum decomposition occurs near physiological pH (near 7.4) while in the acidic (pH < 6) and alkaline (pH > 9) condition CySNO is very stable. This demonstrates that blood provides an optimized environment for the decomposition of CySNO leading to the release of NO. The CySNO decomposition rate can also be affected by buffers with different purity levels in the presence and absence of metal ion chelators—although all buffers show the same pH phenomenon of maximizing near physiological pH. An equilibrium model of metal ions as a function of pH provides a plausible explanation for the pH dependence on the experimental decomposition rate.     

Differential regulation of interleukin-1 receptor associated kinase 1 (IRAK1) splice variants

IRAK family proteins play critical roles in regulating innate immunity. There are three differentially spliced variants of IRAK1, namely 1, 1b, and 1c. We and others have previously identified that the full length IRAK1 underwent covalent modifications such as phosphorylation and ubiquitination upon lipopolysaccharide challenge. In this report, we observed that IRAK1 could also undergo sumoylation which was responsible for its translocation into the nucleus. In contrast, IRAK1c remained stable and did not undergo modification upon various challenges. Furthermore, we showed that IRAK1c solely localized in the cytoplasm. IRAK1 was absent and IRAK1c was the primary form in human brains. The absence of full length IRAK1 and presence of IRAK1c may keep brain tissue in a resting non-inflammatory state. Intriguingly, the full length IRAK1 form was consistently detected in brain tissues obtained from aged humans, suggesting that differential splicing of IRAK1 may correlate with the aging process.     

HLA-associated genetic resistance and susceptibility to type I diabetes in French North Africans and French natives

The distribution of human leukocyte antigen (HLA)-DRB1-DQA1-DQB1 haplotypes was analyzed separately in two distinct French ethnic groups with type I diabetes (T1D), i.e. French North African migrants (n= 64, mean age at diagnosis = 8.25 years) and ancient French natives (n= 60, mean age at diagnosis = 7.42 years). HLA associations were determined by calculating odds ratios (ORs) between patients and two ethnic-matched control populations. Results show highly similar ORs for the conservative DRB1*0301-DQA1*0501-DQB1*0201 haplotype of susceptibility (OR: 3.22 and 3.93 in migrants and natives, respectively) and the DRB1*1501-DQA1*0102-DQB1*0602 haplotype of resistance (OR: 0.05 and 0.03, respectively). In contrast, among the more variable DRB1*04-DQB1*0302 haplotypes of susceptibility, the DRB1*0402 (OR: 3.10 and 32.84) and 0405 (OR: 5.90 and 16.25, respectively) were associated with T1D in migrants and natives, whereas an increase of DRB1*0401, a rare allele in migrants, was significant in natives only. Also, among the DRB1*11-DQA1*0505-DQB1*0301 haplotypes of resistance, the OR observed for DRB1*1104-DQA1*0505-DQB1*0301, common in migrants, was lower (OR: 0.08) than for DRB1*1101-DQA1*0505-DQB1*0301 (OR: 0.32), common in natives. How DRB1*11 subtypes might affect differently the risk conferred by DQA1*0505-DQB1*0301 will be discussed.     

Chronic high-inspired CO2 decreases excitability of mouse hippocampal neurons

To examine the effect of chronically elevated CO(2) on excitability and function of neurons, we exposed mice to 8 and 12% CO(2) for 4 wk (starting at 2 days of age), and examined the properties of freshly dissociated hippocampal neurons obtained from slices. Chronic CO(2)-treated neurons (CC) had a similar input resistance (R(m)) and resting membrane potential (V(m)) as control (CON). Although treatment with 8% CO(2) did not change the rheobase (64 +/- 11 pA, n = 9 vs. 47 +/- 12 pA, n = 8 for CC 8% vs. CON; means +/- SE), 12% CO(2) treatment increased it significantly (73 +/- 8 pA, n = 9, P = 0.05). Furthermore, the 12% CO(2) but not the 8% CO(2) treatment decreased the Na(+) channel current density (244 +/- 36 pA/pF, n = 17, vs. 436 +/- 56 pA/pF, n = 18, for CC vs. CON, P = 0.005). Recovery from inactivation was also lowered by 12% but not 8% CO(2). Other gating properties of Na(+) current, such as voltage-conductance curve, steady-state inactivation, and time constant for deactivation, were not modified by either treatment. Western blot analysis showed that the expression of Na(+) channel types I-III was not changed by 8% CO(2) treatment, but their expression was significantly decreased by 20-30% (P = 0.03) by the 12% treatment. We conclude from these data and others that neuronal excitability and Na(+) channel expression depend on the duration and level of CO(2) exposure and maturational changes occur in early life regarding neuronal responsiveness to CO(2).     

Quantification of in vivo gastric fluid volume in Bama miniature pigs in fasted state

Although the study of bioequivalence waivers in humans is already well‐established, their application and translation into animals, which are complicated by differences in physiology, have only recently become subjects of interest. The main purpose of this paper is to quantify the liquid volume affecting drug dissolution in pig stomachs. We used magnetic resonance imaging (MRI) to scan 18 Bama miniature pigs weighing 15, 30 or 50 kg. Amira 6.0.1 software was used for 3D image processing. We found that the gastric fluid volume had a linear relationship with the weight of pig (R² = 0.9935) over this weight range. The pig weight, therefore, could be used as a surrogate for the fasted gastric fluid volume. After combining data of gastric fluid secretion and drinking water volumes, our results could be used as a reference for the evaluation of oral drug absorption in pigs.