Mesenchymal stem cells contribute to endogenous FVIII:c production

Besides the liver, it has been difficult to identify which organ(s) and/or cellular component(s) contribute significantly to the production of human FVIII:c (FVIII). Thus far, only endothelial cells have been shown to constitute a robust extrahepatic source of FVIII, possibly explaining both the diverse presence of FVIII mRNA in the body, and the observed increase in FVIII levels during liver failure. Here, we investigate whether human mesenchymal stem cells (MSC), ubiquitously present in different organs, could also contribute to FVIII production. MSC isolated from human lung, liver, brain, and bone marrow expressed FVIII message as determined by quantitative‐RT‐PCR. Using an antibody specific for FVIII, confocal microscopy, and umbilical cord‐derived endothelial cells (HUVEC) as a negative control, we demonstrated that, in MSC, FVIII protein was not stored in granules; rather, it localized to the perinuclear region. Furthermore, functional FVIII was detected in MSC supernatants and cell lysates by aPTT and chromogenic assays. These results demonstrate that MSC can contribute at low levels to the functional FVIII pool, and advance the understanding of the physiology of FVIII production and secretion. J. Cell. Physiol. © 2012 Wiley Periodicals, Inc.     

Acute Variations in Retinal Vascular Oxygen Content in a Rabbit Model of Retinal Venous Occlusion

Purpose

To study the variation in intravascular oxygen saturation (oximetry) during an acute retinal vein occlusion (RVO) using hyperspectral computed tomographic spectroscopy based oximetry measurements.

Methods

Thirty rabbits were dilated and anesthetized for experiments. Baseline oximetry measurements were made using a custom-made hyperspectral computed tomographic imaging spectrometer coupled to a fundus camera. RVO were induced using argon green laser following an intravenous injection of Rose Bengal. RVO induction was confirmed by fluorescein angiography. Retinal oximetry measurements were repeated in arterial and venous branches one hour after RVO induction and up to 4 weeks afterwards. Comparison of retinal oximetry before and after vein occlusion was made using the Student T-test.

Results

One hour after RVO induction, we observed statistically significant reductions in the intravascular oxygen saturation in temporal retinal arteries (85.1±6.1% vs. 80.6±6.6%; p<0.0001) and veins (71.4±5.5% vs. 64.0±4.7%; p<0.0001). This decrease was reversible in animals that spontaneously recannulated the vein occlusion. There were no statistically significant differences in oxygen saturation in the nasal control arteries and veins before and after temporal vein RVO induction.

Conclusions

We demonstrate, for the first time, acute changes in the intravascular oxygen content of retinal vessels 1 hour after RVO. These changes are reversible upon spontaneous recannulation of retinal vessels. This study demonstrates that hyperspectral computer tomographic spectroscopy based oximetry can detect physiological variations in intravascular retinal oxygen saturation. The study also provides the first qualitative and quantitative evidence of the variation in retinal vascular oxygen content directly attributable to an acute retinal vein occlusion.     

Bone marrow-derived endothelial progenitor cells contribute to the angiogenic switch in tumor growth and metastatic progression

Emerging evidence indicates that bone marrow (BM)-derived endothelial progenitor cells (EPCs) contribute to angiogenesis-mediated growth of certain tumors in mice and human. EPCs regulate the angiogenic switch via paracrine secretion of proangiogenic growth factors and by direct luminal incorporation into sprouting nascent vessels. While the contributions of EPCs to neovessel formation in spontaneous and transplanted tumors and to the metastatic transition have been reported to be relatively low, remarkably, specific EPC ablation in vivo has resulted in severe angiogenesis inhibition and impaired primary and metastatic tumor growth. The existence of a BM reservoir of EPCs, and the selective involvement of EPCs in neovascularization, have attracted considerable interest because these cells represent novel target for therapeutic intervention. In addition, EPCs are also being used as pharmacodynamic surrogate markers for monitoring cancer progression, as well as for optimizing efficacy of anti-angiogenic therapies in the clinic. This review will focus primarily on recent advances and emerging concepts in the field of EPC biology and discuss ongoing debates involving the role of EPCs in tumor neovascularization. For detailed information on the in vitro characterization of EPCs contribution to non-tumor pathologies, the reader is directed towards several excellent reviews and publications [F. Bertolini, Y. Shaked, P. Mancuso and R.S. Kerbel, Nat. Rev., Cancer 6 (2006) 835–845. [1]] [J.M. Hill, T. Finkel and A.A. Quyyumi, Vox Sang. 87 Suppl 2 (2004) 31–37. [2]] [A.Y. Khakoo and T. Finkel, Annu. Rev. Med. 56 (2005) 79–101. [3]] [H.G. Kopp, C.A. Ramos and S. Rafii, Curr. Opin. Hematol. 13 (2006) 175–181. [4]; K.K. Hirschi, D.A. Ingram and M.C. Yoder, Arterioscler. Thromb. Vasc. Biol. 28 (2008) 1584–1595. [5]; F. Timmermans, J. Plum, M.C. Yoder, D.A. Ingram, B. Vandekerckhove and J. Case, J. Cell. Mol. Med. 13 (2009) 87–102. [6]] and reviews by Bertolini, Voest and Yoder in this issue.     

Begomoviruses Associated with Yellow Leaf Curl Disease of Tomato in Iran*

The occurrence of Tomato yellow leaf curl virus (TYLCV; genus Begomovirus, family Geminiviridae) in the major tomato‐growing areas of Iran was determined using TAS‐ELISA and PCR. The nucleotide sequences of the coat protein (CP) gene and intergenic region (IR) of eight Iranian isolates were determined. CP nucleotide identities among the Iranian isolates were 96–98%, and showed 94–96% identity with TYLCV‐IR [IR:Ira:98] and TYLCV‐IL [IL:Reo:86]. However, they showed low identity (68–69%) with ToLCIRV‐[IR:Ira]. Sequence analyses of IR indicated that seven Iranian isolates had sequence identity of 93–100% with each other, and 76% identity with the Jiroft isolate; identities of 75–79% with TYLCV‐IR[IR:Ira:98] were observed in every case, and 59–62% identity with ToLCIRV‐[IR:Ira]. The IR nucleotide sequences of Iranian isolates showed 92–93% identity with TYLCV‐IL[IL:Reo:86], except the Jiroft isolate (75%). The CP and IR sequence analyses suggested that eight Iranian TYLCV isolates probably differ from ToLCIRV‐[IR:Ira]. Based on IR sequence comparisons and phylogenetic analyses, the Iranian isolates were divided into two groups. The first major group (A), consists of seven virus isolates, was most closely related to TYLCV‐IL[IL:Reo:86], and relatively divergent from TYLCV‐IR [IR:Ira:98] and ToLCIRV‐[IR:Ira]. However, the Jiroft isolate from group B did not show high similarity with TYLCV‐IR[IR:Ira:98], ToLCIRV‐[IR:Ira], and TYLCV‐IL[IL:Reo:86], suggesting that the isolate may be a divergent variant. The differences are in a range that suggests different strains or species from TYLCV‐IR[IR:Ira:98] and ToLCIRV‐[IR:Ira] are probably associated with tomato yellow leaf curl disease in Iran.     

The Environmental Polymorphisms Registry: a DNA resource to study genetic susceptibility loci

The National Institute of Environmental Health Sciences is establishing a DNA repository named the Environmental Polymorphisms Registry (EPR). The goal is to recruit 20,000 subjects from the greater Research Triangle Park region of North Carolina and collect a sample of each subject’s DNA for genetic study. Personal information is obtained from each EPR subject and linked to their sample in coded form. Once individuals with the genotypes of interest are identified, their samples are decoded, and their names and contact information are given to scientists for follow-up studies in which genotype is important. “Recruit-by-genotype” resources such as the EPR require a transparent consent process and rigorous human subjects protection measures. Unlike the EPR, most US DNA resources are anonymous. Once scientists identify potentially significant genetic variants, they must screen new populations to find individuals with the variants of interest to study. The EPR eliminates this time consuming and expensive step. In designing the EPR, consideration was given to achieving high response rates, minimizing attrition and maximizing usefulness for future research studies. Subjects are recruited from outpatient clinics in area medical centers as well as from the general population to ascertain individuals in diverse states of health. Data are collected on race, ethnicity, gender and age, and are monitored for demographic diversity. As of November 2007, 7,788 individuals have been recruited into the EPR and their DNA samples have been used in numerous genetic studies. EPR subjects have also been solicited for several follow-up studies with high response rates (>90%). The success of the EPR based on the number of subjects recruited and genetic studies underway, suggests that it will be a model for future DNA resources.     

Simultaneous Brain–Cervical Cord fMRI Reveals Intrinsic Spinal Cord Plasticity during Motor Sequence Learning

The spinal cord participates in the execution of skilled movements by translating high-level cerebral motor representations into musculotopic commands. Yet, the extent to which motor skill acquisition relies on intrinsic spinal cord processes remains unknown. To date, attempts to address this question were limited by difficulties in separating spinal local effects from supraspinal influences through traditional electrophysiological and neuroimaging methods. Here, for the first time, we provide evidence for local learning-induced plasticity in intact human spinal cord through simultaneous functional magnetic resonance imaging of the brain and spinal cord during motor sequence learning. Specifically, we show learning-related modulation of activity in the C6–C8 spinal region, which is independent from that of related supraspinal sensorimotor structures. Moreover, a brain–spinal cord functional connectivity analysis demonstrates that the initial linear relationship between the spinal cord and sensorimotor cortex gradually fades away over the course of motor sequence learning, while the connectivity between spinal activity and cerebellum gains strength. These data suggest that the spinal cord not only constitutes an active functional component of the human motor learning network but also contributes distinctively from the brain to the learning process. The present findings open new avenues for rehabilitation of patients with spinal cord injuries, as they demonstrate that this part of the central nervous system is much more plastic than assumed before. Yet, the neurophysiological mechanisms underlying this intrinsic functional plasticity in the spinal cord warrant further investigations.     

Application of a dissimilarity index of EEG and its sub-bands on prediction of induced epileptic seizures from rat's EEG signals

ObjectiveEpileptic seizures are defined as manifest of excessive and hyper-synchronous activity of neurons in the cerebral cortex that cause frequent malfunction of the human central nervous system. Therefore, finding precursors and predictors of epileptic seizure is of utmost clinical relevance to reduce the epileptic seizure induced nervous system malfunction consequences. Researchers for this purpose may even guide us to a deep understanding of the seizure generating mechanisms. The goal of this paper is to predict epileptic seizures in epileptic rats.MethodsSeizures were induced in rats using pentylenetetrazole (PTZ) model. EEG signals in interictal, preictal, ictal and postictal periods were then recorded and analyzed to predict epileptic seizures. Epileptic seizures were predicted by calculating an index in consecutive windows of EEG signal and comparing the index with a threshold. In this work, a newly proposed dissimilarity index called Bhattacharyya Based Dissimilarity Index (BBDI), dynamical similarity index and fuzzy similarity index were investigated.ResultsBBDI, dynamical similarity index and fuzzy similarity index were examined on case and control groups and compared to each other. The results show that BBDI outperforms dynamical and fuzzy similarity indices. In order to improve the results, EEG sub-bands were also analyzed. The best result achieved when the proposed dissimilarity index was applied on Delta sub-band that predicts epileptic seizures in all rats with a mean of 299.5 s.ConclusionThe dissimilarity of neural network activity between reference window and present window of EEG signal has a significant increase prior to an epileptic seizure and the proposed dissimilarity index (BBDI) can reveal this variation to predict epileptic seizures. In addition, analyzing EEG sub-bands results in more accurate information about constituent neuronal activities underlying the EEG since certain changes in EEG signal may be amplified when each sub-band is analyzed separately.SignificanceThis paper presents application of a dissimilarity index (BBDI) on EEG signals and its sub-bands to predict PTZ-induced epileptic seizures in rats. Based on the results of this work, BBDI will predict epileptic seizures more accurately and more reliably compared to current indices that increases epileptic patient comfort and improves patient outcomes.     

Oncogenic human papillomavirus genital infection in southern Iranian women: population-based study versus clinic-based data

ABSTRACT: BACKGROUND: Epidemiological studies on genital human papilloma viruses infection (HPVs) in general population are crucial for the implementation of health policy guidelines for developing the strategies to prevent the primary and secondary cervical cancer. In different parts of Iran, there is a lack of population-based studies to determine the prevalence of HPV in the general population. The aim of this population-based study is to compare the prevalence rate of genital HPV infection among reproductive women with our previous clinic-based data, which showed a prevalence rate of 5% in women in southern Iran. RESULTS: Using general primers for all genotypes of HPV, of 799 randomly selected women, five (0.63%, 95% CI 0.23-1.55%) tested positive for HPV DNA. Overall, seven different HPV genotypes were detected: six types (16, 18, 31, 33, 51 and 56) were carcinogenic, or "high risk genotypes" and one genotype (HPV-66) was "probably carcinogenic." CONCLUSIONS: In a population-based study, the prevalence of HPV infection among southern Iranian women was lower than that observed worldwide. However, our gynaecological clinic-based study on the prevalence of HPV infection showed results comparable with other studies in the Middle East and Persian Gulf countries. Since gynaecological clinic-based data may generally overestimate HPV prevalence, estimates of prevalence according to clinic-based data should be adjusted downward by the population-based survey estimates.     

Increased expression of pyruvate carboxylase and biotin protein ligase increases lysine production in a biotin prototrophic Corynebacterium glutamicum strain

Corynebacterium glutamicum, a Gram‐positive bacterium used for the production of various biochemicals, is naturally a biotin auxotroph. We introduced the biotin genes from Bacillus subtilis on a plasmid, pBIO, into a lysine‐producing derivative (termed AHP‐3) that has been described previously, and achieved biotin prototrophy. We found that AHP‐3, containing pBIO, was able to produce lysine in a medium lacking biotin and that the lysine yield on glucose was similar to what is obtained when using a medium containing biotin. However, there was a decrease in specific growth rate of 20% when the strain was cultivated without biotin, indicating a suboptimal intracellular concentration of biotin. In an attempt to locate the potential bottleneck, we added pimelic acid, an early biotin precursor, and found that growth rate could be restored fully, which demonstrates that the bottleneck is in pimeloyl‐CoA (or pimeloyl‐Acyl Carrier Protein [ACP]) formation. Pyruvate carboxylase (pycA), a biotin‐dependent enzyme needed for lysine biosynthesis and biotin ligase (birA), which is responsible for attaching biotin to pyruvate carboxylase, were overexpressed by replacing the native promoters with the strong superoxide dismutase (sod) promoter, to see whether growth could be restored. Neither pycA nor birA overexpression, whether alone or in combination, had an effect on specific growth rate, but they did have a positive effect on lysine yield, which increased by 55% in the strain overexpressing both enzymes.