High level of divergence of male-reproductive-tract proteins, between Drosophila melanogaster and its sibling species, D. simulans

We compared male-reproductive-tract polypeptides of Drosophila melanogaster and D. simulans by using two-dimensional gel electrophoresis. Approximately 64% of male-reproductive-tract polypeptides were identical between two randomly chosen isofemale lines from these two species, compared with 83% identity for third-instar imaginal wing-disc polypeptides. Qualitatively similar differences were found between reproductive tracts and imaginal discs when D. sechellia was compared with D. melanogaster and with D. simulans. When genic polymorphism was taken into account, approximately 10% of male- reproductive-tract polypeptides were apparently fixed for different alleles between D. melanogaster and D. simulans; this proportion is the same as that found for soluble enzymes by one-dimensional gel electrophoresis. Strikingly, approximately 20% of male-reproductive- tract polypeptides of either D. melanogaster or D. simulans had no detectable homologue in the other species. We propose that proteins of the Drosophila male reproductive tract may have diverged more extensively between species than have other types of proteins and that much of this divergence may involve large changes in levels of polypeptide expression.      

Microelectrode studies of the active Na transport pathway of frog skin

When the outer surface of short-circuited frog skin was penetrated with microelectrodes, stable negative potentials that averaged near -100 mV were recorded consistently, confirming the results of Nagel (W. Nagel. 1975. Abstracts of the 5th International Biophysics Congress, Copenhagen. P-147.). The appearance of these stable potentials, V(O), concurrent with the observations that (a) a high resistance outer barrier R(O) accounting for approximately 75 percent or more of the transcellular resistance of control skins had been penetrated and that (b) 10(-5) M amiloride and reduced [Na] outside caused the values of V(O) to increase towards means value near -130 mV while the values of percent R(O) increased to more than 90 percent. It was of relationships were the same as the values of E(1) observed in studies of the current-voltage relationships were the same as the values of E’(1) defined as the values of voltage at the inner barrier when the V(O) of the outer barrier was reduced to zero by voltage clamping of the skins. Accordingly, these data are interpreted to mean that the values of E(1), approximately 130 mV, represent the E(Na) of the sodium pump at the inner barrier. 2,4-DNP was observed to decrease the values of transepithelial voltage less than E(1) the V(O) was negative. These data can be interpreted with a simple electrical equivalent circuit of the active sodium transport pathway of the frog skin that includes the idea that the outer membrane behaves as an electrical rectifier for ion transport.     

Discovery of an intravenous hepatoselective glucokinase activator for the treatment of inpatient hyperglycemia

Glucokinase (hexokinase IV) continues to be a compelling target for the treatment of type 2 diabetes given the wealth of supporting human genetics data and numerous reports of robust clinical glucose lowering in patients treated with small molecule allosteric activators. Recent work has demonstrated the ability of hepatoselective activators to deliver glucose lowering efficacy with minimal risk of hypoglycemia. While orally administered agents require a considerable degree of passive permeability to promote suitable exposures, there is no such restriction on intravenously delivered drugs. Therefore, minimization of membrane diffusion in the context of an intravenously agent should ensure optimal hepatic targeting and therapeutic index. This work details the identification a hepatoselective GKA exhibiting the aforementioned properties.     

Direct intracardiac injection of umbilical cord-derived stromal cells and umbilical cord blood-derived endothelial cells for the treatment of ischemic cardiomyopathy

The development of new therapeutic strategies is necessary to reduce the worldwide social and economic impact of cardiovascular disease, which produces high rates of morbidity and mortality. A therapeutic option that has emerged in the last decade is cell therapy. The aim of this study was to compare the effect of transplanting human umbilical cord-derived stromal cells (UCSCs), human umbilical cord blood-derived endothelial cells (UCBECs) or a combination of these two cell types for the treatment of ischemic cardiomyopathy (IC) in a Wistar rat model. IC was induced by left coronary artery ligation, and baseline echocardiography was performed seven days later. Animals with a left ventricular ejection fraction (LVEF) of ≤40% were selected for the study. On the ninth day after IC was induced, the animals were randomized into the following experimental groups: UCSCs, UCBECs, UCSCs plus UCBECs, or vehicle (control). Thirty days after treatment, an echocardiographic analysis was performed, followed by euthanasia. The animals in all of the cell therapy groups, regardless of the cell type transplanted, had less collagen deposition in their heart tissue and demonstrated a significant improvement in myocardial function after IC. Furthermore, there was a trend of increasing numbers of blood vessels in the infarcted area. The median value of LVEF increased by 7.19% to 11.77%, whereas the control group decreased by 0.24%. These results suggest that UCSCs and UCBECs are promising cells for cellular cardiomyoplasty and can be an effective therapy for improving cardiac function following IC.     

An unusual case of left ventricular aneurysm in duchenne muscular dystrophy

Various structural anomalies of the left ventricular papillary muscles have been observed in recent years. Many of these have been linked to electrocardiographic aberrations. Recently two reports have appeared where the base of the posterior papillary muscle was identified as the source of frequent premature ventricular complexes. In some of these patients these frequent premature ventricular complexes have led to left ventricular dysfunction. In this report a newly discovered structural variant of the anterior papillary muscle is described--the bifid papillary muscle. Furthermore, it is proposed that this bifid papillary muscle is the source of frequent ventricular premature complexes, presenting as bigeminy in a patient with normal left ventricular function.     

Delta12-prostaglandin D2 is a potent and selective CRTH2 receptor agonist and causes activation of human eosinophils and Th2 lymphocytes

Prostaglandin D2 (PGD2) is a lipid mediator produced by mast cells, macrophages and Th2 lymphocytes and has been detected in high concentrations in the airways of asthmatic patients. There are two receptors for PGD2, namely the D prostanoid (DP) receptor and the chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2). The proinflammatory effects of PGD2 leading to recruitment of eosinophils and Th2 lymphocytes into inflamed tissues is thought to be predominantly due to action on CRTH2. Several PGD2 metabolites have been described as potent and selective agonists for CRTH2. In this study we have characterized the activity of delta12-PGD2, a product of PGD2 isomerization by albumin. Delta12-PGD2 induced calcium mobilization in CHO cells expressing human CRTH2 receptor, with efficacy and potency similar to those of PGD2. These effects were blocked by the TP/CRTH2 antagonist ramatroban. delta12-PGD2 bound to CRTH2 receptor with a pKi of 7.63, and a 55-fold selectivity for CRTH2 compared to DP. In Th2 lymphocytes, delta12-PGD2 induced calcium mobilization with high potency and an efficacy similar to that of PGD2. delta12-PGD2 also caused activation of eosinophils as measured by shape change. Taken together, these results show that delta12-PGD2 is a potent and selective agonist for CRTH2 receptor and can cause activation of eosinophils and Th2 lymphocytes. These data also confirm the selective effect of other PGD2 metabolites on CRTH2 and illustrate how the metabolism of PGD2 may influence the pattern of leukocyte infiltration at sites of allergic inflammation.     

Most nuclear systemic autoantigens are extremely disordered proteins: implications for the etiology of systemic autoimmunity

Patients with systemic autoimmune diseases usually produce high levels of antibodies to self-antigens (autoantigens). The repertoire of common autoantigens is remarkably limited, yet no readily understandable shared thread links these apparently diverse proteins. Using computer prediction algorithms, we have found that most nuclear systemic autoantigens are predicted to contain long regions of extreme structural disorder. Such disordered regions would generally make poor B cell epitopes and are predicted to be under-represented as potential T cell epitopes. Consideration of the potential role of protein disorder may give novel insights into the possible role of molecular mimicry in the pathogenesis of autoimmunity. The recognition of extreme autoantigen protein disorder has led us to an explicit model of epitope spreading that explains many of the paradoxical aspects of autoimmunity – in particular, the difficulty in identifying autoantigen-specific helper T cells that might collaborate with the B cells activated in systemic autoimmunity. The model also explains the experimentally observed breakdown of major histocompatibility complex (MHC) class specificity in peptides associated with the MHC II proteins of activated autoimmune B cells, and sheds light on the selection of particular T cell epitopes in autoimmunity. Finally, the model helps to rationalize the relative rarity of clinically significant autoimmunity despite the prevalence of low specificity/low avidity autoantibodies in normal individuals.     

Inhaled nitric oxide decreases infarction size and improves left ventricular function in a murine model of myocardial ischemia-reperfusion injury

To learn whether nitric oxide (NO) inhalation can decrease myocardial ischemia-reperfusion (I/R) injury, we studied a murine model of myocardial infarction (MI). Anesthetized mice underwent left anterior descending coronary artery ligation for 30, 60, or 120 min followed by reperfusion. Mice breathed NO beginning 20 min before reperfusion and continuing thereafter for 24 h. MI size and area at risk were measured, and left ventricular (LV) function was evaluated using echocardiography and invasive hemodynamic measurements. Inhalation of 40 or 80 ppm, but not 20 ppm, NO decreased the ratio of MI size to area at risk. NO inhalation improved LV systolic function, as assessed by echocardiography 24 h after reperfusion, and systolic and diastolic function, as evaluated by hemodynamic measurements 72 h after reperfusion. Myocardial neutrophil infiltration was reduced in mice breathing NO, and neutrophil depletion prevented inhaled NO from reducing myocardial I/R injury. NO inhalation increased arterial nitrite levels but did not change myocardial cGMP levels. Breathing 40 or 80 ppm NO markedly and significantly decreased MI size and improved LV function after ischemia and reperfusion in mice. NO inhalation may represent a novel method to salvage myocardium at risk of I/R injury.     

EFFECTS OF HUMAN ACTIVITIES ON STRUCTURE AND COMPOSITION OF WOODY SPECIES OF THE NOKREK BIOSPHERE RESERVE OF MEGHALAYA,NORTHEAST INDIA

Aims Our study was conducted in the Nokrek Biosphere Reserve (NBR) in the Garo hills districts of Meghalaya, Northeast India. Our aim was to assess the effects of human activities on plant diversity,population structure and regeneration.Methods We selected a representative 1.2 hm2 stand in both the core and buffer zones of NBR. Structure and composition were determined by randomly sampling square quadrats, population structure was assessed by determining age structure, and regeneration was assessed by measuring densities of seedling, sapling and adult trees.Important findings More woody species were recorded from the core zone than the buffer zone (87 vs. 81 species), and there were a large number of tropical, temperate, and Sino-Himalayan, Burma-Malaysian and Malayan elements, primitive families and primitive genera. The trees were distributed in three distinct strata,canopy, subcanopy and sapling. Subcanopy and sapling layers had the highest species richness (81％ -88％ ). Lauraceae and Euphorbiaceae were the dominant families in terms of the number of species, and a large number of families were represented by single species. Most woody species (57 ％ - 79 ％ ) were contagiously distributed and had low frequency ( ＜ 20％ ). Although stand density was high in the buffer zone, its basal area was low compared to the stand in the core zone. Low similarity and high β-diversity indicate marked differences in species composition of the stands. Shannon diversity index was high in both the stands, while Simpson dominance index was low. The diameter-class distribution for dominant species revealed that the most had a large number of young individuals in their populations. Preponderance of tree seedlings, followed by a steep decline in population density of saplings and adult trees, indicated that the seedling to sapling stage was the most critical in the life cycle of the tree populations. Most species (42 ％ - 48 ％ ) had no regeneration,25 ％ - 35 ％ had good/fair regeneration, and the rest had poor regeneration or reoccurred as immigrants.     

Functional resolution of fibrosis in mdx mouse dystrophic heart and skeletal muscle by halofuginone

The effect of halofuginone (Halo) on established fibrosis in older mdx dystrophic muscle was investigated. Mice (8 to 9 mo) treated with Halo (or saline in controls) for 5, 10, or 12 wk were assessed weekly for grip strength and voluntary running. Echocardiography was performed at 0, 5, and 10 wk. Respiratory function and exercise-induced muscle damage were tested. Heart, quadriceps, diaphragm, and tibialis anterior muscles were collected to study fibrosis, collagen I and III expression, collagen content using a novel collagenase-digestion method, and cell proliferation. Hepatocyte growth factor and alpha-smooth muscle actin proteins were assayed in quadriceps. Halo decreased fibrosis (diaphragm and quadriceps), collagen I and III expression, collagen protein, and smooth muscle actin content after 10 wk treatment. Muscle-cell proliferation increased at 5 wk, and hepatocyte growth factor increased by 10 wk treatment. Halo markedly improved both cardiac and respiratory function and reduced damage and improved recovery from exercise. The overall impact of established dystrophy and dysfunction in cardiac and skeletal muscles was reduced by Halo treatment. Marked improvements in vital-organ functions implicate Halo as a strong candidate drug to reduce morbidity and mortality in Duchenne muscular dystrophy.