In cardiac muscle, mitochondrial ATP synthesis is driven by demand for ATP through feedback from the products of ATP hydrolysis. However, in skeletal muscle at higher workloads there is an apparent contribution of open-loop stimulation of ATP synthesis. Open-loop control is defined as modulation of flux through a biochemical pathway by a moiety, which is not a reactant or a product of the biochemical reactions in the pathway. The role of calcium, which is known to stimulate the activity of mitochondrial dehydrogenases, as an open-loop controller, was investigated in isolated cardiac and skeletal muscle mitochondria. The kinetics of NADH synthesis and respiration, feedback from ATP hydrolysis products, and stimulation by calcium were characterized in isolated mitochondria to test the hypothesis that calcium has a stimulatory role in skeletal muscle mitochondria not apparent in cardiac mitochondria. A range of respiratory states were obtained in cardiac and skeletal muscle mitochondria utilizing physiologically relevant concentrations of pyruvate and malate, and flux of respiration, NAD(P)H fluorescence, and rhodamine 123 fluorescence were measured over a range of extra mitochondrial calcium concentrations. We found that under these conditions calcium stimulates NADH synthesis in skeletal muscle mitochondria but not in cardiac mitochondria.

Background:Neonates often develop thrombocytopenia at some time during hospital stay. Platelet transfusion are frequently given to them and are likely to result in unnecessary transfusion.Material and Methods:Thus, we analyzed thrombocytopenia in neonates, its prevalence, and relationship if any, between clinical condition and platelet transfusion in neonates, which would have been helpful in developing guidelines and/or protocols for platelet transfusion (and reducing the donor exposure) in neonates.Results:A total of 870 neonates who were admitted in Neonatal Intensive Care Unit (NICU) with various morbidities had platelets count done; of these, 146 (16.7%) neonate revealed thrombocytopenia.Discussion:Low birth weight babies (P 0.009) and babies born with mother having hypertension (P 0.04) showed significant thrombocytopenia. Neonates with intrauterine growth retardation (IUGR) diagnosed during antenatal screening showed lower platelet count (P 0.022). Neonates having associated illness, such as sepsis, gastrointestinal, and respiratory problems, and on vasopressor drugs were found to be associated with low platelet count.Conclusion:In our study, 16.40% of thrombocytopenic neonates required platelet transfusion either alone or with other blood component during their stay in NICU.

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We report the first PNA self-replicating system based on template directed cross-catalytic ligation, a process analogous to biological replication. Using two template PNAs and four pentameric precursor PNAs, all four possible carbodiimide assisted amide ligation products were detected and identified by HPLC and MALDI-TOF analysis. We conclude that the two template complementary reaction products are generated via cross-catalysis, while the other two self-complementary (and in principle auto-catalytic) products are formed via intra-complex coupling between the two sets of complementary PNA precursors. Cross-catalytic product formation followed product inhibited kinetics, but approximately two replication rounds were observed. Analogous but less efficient replication was found for a similar tetrameric system. These results demonstrate that simpler nucleobase replication systems than natural oligonucleotides are feasible, thereby strengthening the foundation for the discussion of a possible role for PNA (like) genetic material in the prebiotic evolution of life and lay the ground for further studies into evolution of such potentially prebiotic systems.

It is important to obtain a good withdrawal pressure tracing while performing cardiac catheterization in cases with right ventricular outflow tract (RVOT) obstruction to document the site and severity of obstruction. However efforts to manipulate the catheter in the RVOT (either to obtain the gradients or to position the catheter for an outflow angiogram) can sometimes precipitate severe dynamic RVOT obstruction with complete cessation of forward flow leading to life threatening hypotension. The following hemodynamic traces highlight this rare phenomenon which needs to be borne in mind at all times while performing cardiac catheterization in such patients.

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Peptide synthesis is a fundamental feature of life. However, it still remains unclear how the contemporary translation apparatus evolved from primitive prebiotic systems and at which stage of the evolution peptide synthesis emerged. Using simple molecular architectures, in which aminoacyl transfer of phenylalanine occurs either between two ends of a PNA stem loop structure, between two PNAs in a duplex, or between two PNAs assembled on a PNA template, we show that bona fide template instructed phenylalanine transfer can take place. Thus, we have identified conditions which allow template assisted intermolecular aminoacyl transfer using simple ester aminolysis chemistry primitively analogous to the ribosomal peptidyl transferase reaction in the absence of anchimeric assistance from ribose and ribosome catalysis. These results help define the minimum chemical boundary conditions for the translation process and also give insight into the possibilities for the prebiotic emergence of RNA-independent translation.

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