Transcatheter closure of the patent arterial duct using the Flipper coil in a premature infant weighing 1,400 g: a case report.

A symptomatic 1,400 g premature triplet underwent successful transcatheter coil embolization of patent arterial duct using the umbilical artery. One 3 mm x 3 cm Flipper coil was used with no angiographic residual shunt. To the best of our knowledge, this is one of the smallest preterm infants to undergo this transcatheter procedure.     

Chest pain among adolescents with anorexia nervosa

Chest pain is common among adolescents. However, chest pain among adolescents with eating disorders is unique. We report a case of an anorexic adolescent presenting to the emergency room with acute onset of chest pain due to spontaneous pneumomediastinum. The pathophysiology, etiology, and risk factors of chest pain among adolescents with anorexia nervosa are reviewed.     

Single-stage repair of tetralogy of Fallot with pseudoaneurysm: a unique approach

Pseudoaneurysm is a potentially lethal complication after modified Blalock-Taussig shunt. This report describes a frequently misdiagnosed clinical presentation along with noninvasive diagnosis of pseudoaneurysm after a modified Blalock-Taussig shunt. We report a novel single-stage surgical management of the pseudoaneurysm with concomitant complete repair of tetralogy of Fallot.     

Bilirubin,a new therapeutic for kidney transplant?

In patients with end-stage renal disease, kidney transplantation has been associated with numerous benefits, including increased daily activity, and better survival rates. However, over 20% of kidney transplants result in rejection within five years. Rejection is primarily due to a hypersensitive immune system and ischemia/reperfusion injury. Bilirubin has been shown to be a potent antioxidant that is capable of potentially reversing or preventing damage from reactive oxygen species generated from ischemia and reperfusion. Additionally, bilirubin has several immunomodulatory effects that can dampen the immune system to promote organ acceptance. Increased bilirubin has also been shown to have a positive impact on renal hemodynamics, which is critical post-transplantation. Lastly, bilirubin levels have been correlated with biomarkers of successful transplantation. In this review, we discuss a multitude of potentially beneficial effects that bilirubin has on kidney acceptance of transplantation based on numerous clinical trials and animal models. Exogenous bilirubin delivery or increasing endogenous levels pre- or post-transplantation may have therapeutic benefits.     

Innovative technique for repair of Tetralogy of Fallot with absent pulmonary,valve syndrome using autologous pericardial patch with monocusp valve

Background  Conventional surgery for absent pulmonary valve is repair with valve conduit between right ventricle (RV) and Pulmonary artery (PA).We describe a technique of repairing absent pulmonary valve with autologous pericardial patch with monocusp valve, without using valve conduit and its results. Methods  From February 2004 to September 2006, 14 consecutive patients with absent pulmonary valve syndrome (APVS) were repaired using this technique. Age range was 5–168 months (median- 24 months) and weight range was 6–31 kgs (median-10 kgs), 5 were infants. Varying degree of respiratory symptoms were present in all patients including tachypnoea, difficulty in feeding, wheezing, recurrent pneumonia and cyanosis. Repair consisted of ventricular septal defect closure, relief of right ventricular outflow obstruction with autologous pericardial patch with monocusp valve. PA aneurysmorrhaphy and PA reduction arterioplasty were done in selected cases. Result  There was one mortality. The follow up ranged from 12 months to 36 months, respiratory symptoms disappeared or were significantly improved in all patients. Two dimensional (2D) Echo showed trivial to mild pulmonary regurgitation (PR) in 11 patients & moderate in two patients. One patient had minimal right ventricular outflow tract (RVOT) obstruction. None of them required reintervention. Conclusion  New innovative technique of using autologous pericardial patch with monocusp valve in absent pulmonary valve syndrome can be safely performed in infants and children. It avoids conduit related problems like reintervention and is economical. Our early and midterm results are encouraging, however long term results are awaited.     

Childhood angina due to congenital atresia of the coronary sinus

A young child with exertional chest pain, and an electrocardiographic pattern suggesting reversible ischaemia of the anterior ventricular wall documented by Cardiolyte stress-testing, underwent cardiac catheterization and selective coronary angiography. Although the coronary arteries were entirely normal, the recirculation phase demonstrated marked dilation of the coronary sinus, with atresia of its mouth. At surgery, the patient was confirmed to have muscular atresia at the mouth of the coronary sinus, and underwent unroofing of the coronary sinus to the left atrium, with ligation of a persistent left superior caval vein. Post-operatively, the patient continued to have persistent chest pain, albeit without inducible ischaemia on stress-testing.     

Dynamic JUNQ inclusion bodies are asymmetrically inherited in mammalian cell lines through the asymmetric partitioning of vimentin

Aging is associated with the accumulation of several types of damage: in particular, damage to the proteome. Recent work points to a conserved replicative rejuvenation mechanism that works by preventing the inheritance of damaged and misfolded proteins by specific cells during division. Asymmetric inheritance of misfolded and aggregated proteins has been shown in bacteria and yeast, but relatively little evidence exists for a similar mechanism in mammalian cells. Here, we demonstrate, using long-term 4D imaging, that the vimentin intermediate filament establishes mitotic polarity in mammalian cell lines and mediates the asymmetric partitioning of damaged proteins. We show that mammalian JUNQ inclusion bodies containing soluble misfolded proteins are inherited asymmetrically, similarly to JUNQ quality-control inclusions observed in yeast. Mammalian IPOD-like inclusion bodies, meanwhile, are not always inherited by the same cell as the JUNQ. Our study suggests that the mammalian cytoskeleton and intermediate filaments provide the physical scaffold for asymmetric inheritance of dynamic quality-control JUNQ inclusions. Mammalian IPOD inclusions containing amyloidogenic proteins are not partitioned as effectively during mitosis as their counterparts in yeast. These findings provide a valuable mechanistic basis for studying the process of asymmetric inheritance in mammalian cells, including cells potentially undergoing polar divisions, such as differentiating stem cells and cancer cells.Aging is universally associated with a global decline in cellular function (1–3). Due to the multiplicity of mechanisms that undergo aging-related dysfunction, its mechanistic basis, or “senescence factor,” has been difficult to pinpoint. Several studies have provided key insight into the identities of senescence factors by studying the asymmetric segregation of damage in single-cell organisms that rejuvenate the emerging generation by preventing the inheritance of damaged factors such as DNA, lipids, and proteins (1, 4, 5). In particular, a number of seminal studies have demonstrated that bacteria and yeast use a complex and multifaceted machinery to prevent the inheritance of damaged and aggregated proteins by the new generation by restricting them to the older lineage during cell division (1, 6, 7).Although the precise mechanism for asymmetric inheritance of aggregates has been a matter of much debate (1, 7), the emerging model is that the spatial arrangement of misfolded proteins into quality control-associated IB (inclusion body)-like structures plays an essential role in asymmetric inheritance (1, 7). A key property of some quality-control IBs and other IB-like structures, which allows the cell to retain them in a specific lineage during mitosis, is their association and interaction with cellular organelles and cytoskeleton. In bacteria, for example, aggregated proteins are collected at the old pole of a dividing cell (5). A similar mechanism has been proposed in fission yeast (8). In the budding yeast Saccharomyces cerevisiae, several detailed studies demonstrated interdependence between asymmetric inheritance and the maintenance of the actin cytoskeleton and, in particular, the polarisome complex, which anchors the actin cytoskeleton in the emerging bud (9). Compromising the architecture of the actin cytoskeleton, even for a single generation, leads to a decrease in the replicative lifespan of the emerging cells (4).Yeast cells manage the triage of protein misfolding and aggregation by spatially partitioning subpopulations of misfolded proteins to several membrane-less cytosolic quality-control IBs (10, 11). Upon misfolding, substrates localize to transient stress foci (SFs), which concentrate chaperones, holdases, and disaggregases (7). SFs are dynamic IBs that form in response to acute stress and may participate in the triage decision of whether to refold, degrade, or aggregate misfolded proteins (7). As misfolded substrates accumulate, and especially in response to external stresses, they accumulate in two quality-control IBs: Proteins targeted for degradation are directed to the JUNQ compartment and proteins that are targeted for active aggregation are directed to an insoluble IPOD compartment (10). Recently, we have demonstrated a new vital role for these inclusions in asymmetric inheritance of aggregates (or spatial quality-control/replicative rejuvenation) in yeast (7). The IPOD and JUNQ are selectively retained in the mother cell during budding. This asymmetry is due to the fact that IPOD and JUNQ are tethered to organelles. Critically, proteins that were trapped in SFs, and therefore failed to migrate to IPOD or JUNQ in time for mitosis, were passed on to successive generations of daughter cells (7).Although a similar replicative rejuvenation mechanism in multicellular organisms has been sought after for some time, only a few seminal studies have found evidence for asymmetric aggregate segregation during mammalian or Drosophila mitosis (12, 13, 14). The mechanism for directing misfolded proteins to different inclusions structures, however, appears to be at least partially conserved from yeast to mammals. In previous work, we have demonstrated the existence of distinct IBs in human cultured cells: a JUNQ-like IB and an IPOD-like IB (from here on JUNQ and IPOD) (15, 16). The JUNQ contains mobile aggregates and accumulates chaperones, such as Hsp70, and active proteasomes (15). The IPOD sequesters insoluble amyloid aggregates from the rest of the cytosol (15). In striking similarity to the yeast JUNQ, the properties of the mammalian JUNQ are highly sensitive to stress. Under low-stress conditions, the JUNQ is a dynamic liquid phase compartment with high-degradation capacity (11, 17). Increased exposure to misfolding stress or localization of disease-associated proteins to the JUNQ instead of the IPOD leads to the maturation of the JUNQ into a less dynamic solid phase compartment, inhibiting degradation and eventually killing the cell (15, 18).We set out to examine the mechanism of mitotic inheritance of misfolded proteins and aggregates in mammalian cells. Using long-term 4D imaging (19), we demonstrate asymmetric inheritance of JUNQ IBs during mitosis. Although the IPOD, containing amyloidogenic proteins, is frequently inherited by the same cell as the JUNQ, it is sometimes misinherited. Similar to yeast, we observe SFs in mammalian cells, which fail to be retained asymmetrically. We show that the inheritance of the JUNQ is mediated by the association of the JUNQ with the cytoskeleton. The misfolded proteins in the JUNQ are confined by a network of vimentin intermediate filaments and sometimes also actin (20). Whereas in yeast the JUNQ and IPOD are both tethered to organelles, the mammalian IPOD does not appear to specifically associate with the cytoskeleton or the MTOC (Microtubule Organizing Center). Therefore, a critical difference between yeast and mammalian asymmetry mechanisms may be a reduced ability to maintain the partitioning of insoluble amyloid aggregates. Finally, we show that replicative rejuvenation may confer a slight fitness advantage, under certain conditions, on the daughter cell that fails to inherit a JUNQ. In addition to uncovering a novel replicative rejuvenation mechanism in higher eukaryotes, our study suggests that vimentin establishes an axis of mitotic polarity in mammalian cells.     

Microfluidic generation of haptotactic gradients through 3D collagen gels for enhanced neurite growth

We adapted a microfluidic system used previously to generate durotactic gradients of stiffness in a 3D collagen gel, to produce haptotactic gradients of adhesive ligands through the collagen gel. Oligopeptide sequences that included bioactive peptide sequences from laminin, YIGSR, or IKVAV, were grafted separately onto type I collagen using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). Solutions of peptide-grafted collagen and untreated collagen were then used as source and sink input solutions, respectively, in an H-shaped microfluidic network fabricated using traditional soft lithography. One-dimensional gradients of the peptide-grafted collagen solution were generated in the channel that connected the source and sink channels, and these gradients became immobilized upon self-assembly of the collagen into a 3D fibrillar gel. The slope and average concentration of the gradients were adjusted by changing the concentration of the source solutions and by changing the length of the cross-channel. A separate, underlying channel in the microfluidic construct allowed the introduction of a chick embryo dorsal root ganglion into the network. Neurites from these explants grew significantly longer up steep gradients of YIGSR, but shallow gradients of IKVAV in comparison to untreated collagen controls. When these two gradients were presented in combination, the bias in growth acceleration was the largest and most consistent. No differences were observed in the number of neurites choosing to grow up or down the gradients in any condition. These results suggest that the incorporation of distinct gradients of multiple bioactive ligands can improve directional acceleration of regenerating axons.     

Genipin-induced changes in collagen gels: correlation of mechanical properties to fluorescence

Controlled crosslinking of collagen gels has important applications in cell and tissue mechanics as well as tissue engineering. Genipin is a natural plant extract that has been shown to crosslink biological tissues and to produce color and fluorescence changes upon crosslinking. We have characterized the effects of genipin concentration and incubation duration on the mechanical and fluorigenic properties of type I collagen gels. Gels were exposed to genipin (0, 1, 5, or 10 mM) for a defined duration (2, 4, 6, or 12 h). Mechanical properties were characterized using parallel plate rheometry, while fluorigenic properties were examined with a spectrofluorimetric plate reader and with a standard, inverted epifluorescent microscope. Additionally, Fourier transform infrared spectroscopy was used to characterize and track the crosslinking reaction in real-time. Genipin produced significant concentration- and incubation-dependent increases in the storage modulus, loss modulus, and fluorescence intensity. Storage modulus was strongly correlated to fluorescence exponentially. Minimal cytotoxicity was observed for exposure of L929 fibroblasts cultured within collagen gels to 1 mM genipin for 24 h, but significant cell death occurred for 5 and 10 mM genipin. We conclude that genipin can be used to stiffen collagen gels in a relatively short time frame, that low concentrations of genipin can be used to crosslink cell-populated collagen gels to affect cell behavior that is influenced by the mechanical properties of the tissue scaffold, and that the degree of crosslinking can be reliably assayed optically via simple fluorescence measurements.     

Identification of subtype C human immunodeficiency virus type 1 by subtype-specific PCR and its use in the characterization of viruses circulating in the southern parts of India

Human immunodeficiency virus type 1 (HIV-1) subtype C viruses are associated with nearly half of worldwide HIV-1 infections and are most predominant in India and the southern and eastern parts of Africa. Earlier reports from India identified the preponderance of subtype C and a small proportion of subtype A viruses. Subsequent reports identifying multiple subtypes suggest new introductions and/or their detection due to extended screening. The southern parts of India constitute emerging areas of the epidemic, but it is not known whether HIV-1 infection in these areas is associated with subtype C viruses or is due to the potential new introduction of non-subtype C viruses. Here, we describe the development of a specific and sensitive PCR-based strategy to identify subtype C-viruses (C-PCR). The strategy is based on amplifying a region encompassing a long terminal repeat and gag in the first round, followed by two sets of nested primers; one amplifies multiple subtypes, while the other is specific to subtype C. The common HIV and subtype C-specific fragments are distinguishable by length differences in agarose gels and by the difference in the numbers of NF-kappaB sites encoded in the subtype C-specific fragment. We implemented this method to screen 256 HIV-1-infected individuals from 35 towns and cities in four states in the south and a city in the east. With the exception of single samples of subtypes A and B and a B/C recombinant, we found all to be infected with subtype C viruses, and the subtype assignments were confirmed in a subset by using heteroduplex mobility assays and phylogenetic analysis of sequences. We propose the use of C-PCR to facilitate rapid molecular epidemiologic characterization to aid vaccine and therapeutic strategies.