Absence of lysozyme (muramidase) in the intestinal Paneth cells of newborn infants with necrotising enterocolitis

Day surgery (DS) especially in children, has been widely accepted by surgeons, and the benefits to the patients, parents, and hospital have been well-established. It has become particularly popular among working parents and is accepted by hospital administrators. Proper case selection, preoperative assessment, and proper parent counselling, choice of anaesthesia, postoperative analgesia, and follow-up advice are essential for a successful outcome. This paper records our experience with 465 infants and children who underwent DS at Government Stanley Hospital and two semi-charitable trust hospitals in Madras during the years 1985-1986. The overall acceptance of the programme was excellent, with minimal complications and a fallout rate of 9.6%. The advantages of DS in our environment are discussed.     

Polymorphism of noncoding regions of the mitochondrial genome in the indigenous population of Southeastern Tuva Republic

Deletion-insertion polymorphism of the V region and restriction polymorphism of D-loop for seven restriction enzymes--AspS9I (Cfr3I isoschizomere), BamHI, Bme18I (AvaII), EcoRV, HaeIII, KpnI, and Kzo9I (Sau3AI)--in mitochondrial DNA (mt DNA) were studied in the indigenous population of southeastern Tuva Republic. The results were compared with the data on Russians, Mongols, Buryats, and Altaians. Tuvinians significantly differed from Mongols in the frequency of the 9-bp deletion of the V region (1.89 and 8.07%, respectively). Additionally, significant differences between Tuvinians and samples of Mongols and Russians were obtained for frequencies of the AspS9I, HaeIII, and KpnI restriction sites. A comparison of the polymorphism of mitochondrial genome in individuals of different sexes and ages was performed in the studied sample.     

Molecular modeling of the transmembrane segment of Na+-K+-ATPase. A pentagonal model]

Retrograde differentiation (or dedifferentiation) has recently been proposed as a pathogenetic mechanism involved also in various renal diseases. Here we studied whether evidence of these mechanisms can be found in the kidneys of patients with congenital nephrotic syndrome of the Finnish type (CNF). These patients show isolated massive proteinuria but no primary symptoms from any other organ systems. For the analysis we used antibody markers of early (fibronectin, stem cell factor, Wilms' tumor gene product, cytokeratin) and later (laminin, midgestation and kidney, heparin binding growth-associated molecule) stages of nephron differentiation as well as for apoptosis (acridine orange staining), rescue from apoptosis (anti-Bcl-2 antibodies) and cell proliferation (antibodies to proliferating cell nuclear antigen). In the peritubular spaces atypically organized areas were found which appeared positive with markers of low stages of differentiation, but neither abnormal cell proliferation nor activation of the apoptotic pathway could be detected. As morphologic signs of abnormal tissue organization, we found clusters of tightly compacted and large glomeruli corresponding to the size of two to three normal glomeruli. However, all individual glomerular cell compartments (mesangial, endothelial, visceral epithelial cells) appeared balanced in relative cell numbers. Together these results may indicate abnormal early mesenchymoepithelial tissue interaction leading to excessive and poorly organized formation of glomeruli. This could be causally related also to the serious functional immaturity of CNF kidneys presented as isolated proteinuria.     

The physiological indices of pre-examination stress

Overexpression of Bcl-2 and related anti-apoptotic gene products has been shown to increase the intracellular concentration of the antioxidant tripeptide glutathione in neuronal and hematopoietic cells. A similar examination of HeLa cells that stably overexpress Bcl-2 (Bcl-2/HeLa) demonstrated that the reduced form of glutathione (GSH) was increased by 60% compared to control cells (80 nmol GSH/mg protein compared to 50 nmol GSH/mg). Expression of gamma-glutamylcysteine synthetase, the rate limiting enzyme for glutathione synthesis was found to be independent of Bcl-2 overexpression, as determined by Northern blot analysis and immunoprecipitation of [35-S]-labeled enzyme. Bcl-2 overexpression did not alter the rate of GSH biosynthesis, measured under steady state conditions. Thus, the increase in GSH concentration was not the result of increased synthesis. Two activities have been described which govern efflux of reduced glutathione (GSH), RsGshT known as the sinusoidal transporter and RcGshT, known as the canalicular transporter. Both are low affinity, bidirectional, ATP and Na-independent. Consistent with expression of sinusoidal activity, DTT was found to stimulate GSH efflux while the amino acid methionine inhibited efflux in both HeLa and Bcl-2/HeLa cells. However, methionine-dependent inhibition of efflux was found to be significantly increased by expression of Bcl-2. To test the prediction that the increase in GSH observed in Bcl-2/HeLa cells was mediated by methionine; Bcl-2/HeLa cells were cultured for 24 hrs in methionine-free growth medium. Under these conditions, the GSH concentration of the Bcl-2/HeLa cells dropped to the level observed in HeLa cells (50 nmol GSH/mg protein). These studies suggest that overexpression of Bcl-2 increases GSH levels by altering methionine-dependent GSH efflux, an activity associated in HeLa cells with expression of the RsGshT transporter.     

Dual feeding active integrated antenna

A dual feeding active integrated antenna with high isolation between the Tx and Rx ports of a single triangular patch antenna is presented. The proposed antenna suppresses the third harmonics and isolates the Tx signal at the Rx ports to a high degree. The measured results of the return loss, isolation, and radiation patterns are provided     

Finite element analysis of fluid flows with moving boundary

The objective of the present study is to analyze the fluid flow with moving boundary using a finite element method. The algorithm uses a fractional step approach that can be used to solve low-speed flow with large density changes due to intense temperature gradients. The explicit Lax-Wendroff scheme is applied to nonlinear convective terms in the momentum equations to prevent checkerboard pressure oscillations. The ALE (Arbitrary Lagrangian Eulerian) method is adopted for moving grids. The numerical algorithm in the present study is validated for two-dimensional unsteady flow in a driven cavity and a natural convection problem. To extend the present numerical method to engine simulations, a piston-driven intake flow with moving boundary is also simulated. The density, temperature and axial velocity profiles are calculated for the three-dimensional unsteady piston-driven intake flow with density changes due to high inlet fluid temperatures using the present algorithm. The calculated results are in good agreement with other numerical and experimental ones.     

A parallel DNA triplex as a model for the intermediate in homologous recombination

Parallel DNA triplexes considered to be putative intermediates in homologous recombination, are studied by means of theoretical conformational analysis. These triplexes are denoted as the R-form DNA. Two types of triplexes are analyzed: extended R-form DNA, modeling the triple standard structure, created transiently in the presence of recombination proteins (e.g. RecA); and collapsed R-form, obtained after deproteinization. These structures are stereochemically possible for any arbitrary sequence and have the following properties: (1) the third, R-strand, is parallel to the identical duplex strand and is located in the major groove of the duplex; (2) positions of all four bases in the R-strand are nearly isomorphic; (3) the proposed triplets are consistent with the chemical modification data for deproteinized DNA; we suggest, however, that they are the same in the RecA-DNA complex as well. Since the patterns of charges on each base of the R-strand are strictly complementary to the charges of the homologous Watson-Crick (WC) pair in the major groove, we propose that the selection of the homologous sequence may occur through these complementary electrostatic interactions (electrostatic recognition code). We demonstrate that in the collapsed triplex with a rise of about 3.4 A, the bases from the third R-strand can be inclined and interact with two WC base-pairs simultaneously, which could lead to recognition errors. These mispairings are unlikely in the extended triplex. Therefore, we speculate that a functional role of the extended and underwound DNA structure, transiently formed in the complex with RecA protein, is to obviate such errors and increase the stringency of recognition. In other words, RecA plays the role of a DNA chaperone facilitating the recognition of the single stranded DNA and the duplex. Finally, we show that the proposed isomorphic triplets are conformationally advantageous for strand exchange.     

One‐Step Hierarchical Assembly of Spheres‐in‐Lamellae Nanostructures from Solvent‐Annealed Thin Films of Binary Diblock Copolymer Micelles

Hierarchical assemblies of dissimilar block copolymers (BCPs) can reveal interesting perspectives on material properties and device performance by providing multiple functionalities. Up to now, hierarchical assemblies of BCPs have been mostly prepared by stepwise assembling methods, in which the first type of BCP nanodomains is used as predefined patterns to guide the second‐level assembly of another BCP. On the other hand, single‐step blending methods suffer from a dilemma in the creation of hierarchical patterns because blending dissimilar BCPs typically induces either macrophase separation of component BCPs or chain‐level hybridization into a single morphology. The present study is designed to overcome this apparent dilemma in polymer blends by exploiting a solvent annealing method. In particular, hierarchically assembled spheres‐in‐lamellae structures from a solvent‐annealed blended film of binary polystyrene‐block‐poly(2‐vinylpyrdine) and polystyrene‐block‐poly(4‐vinyl pyridine) micelles are prepared. The focus of the current study is to understand the different effects of solvent vapor on the component BCPs and the molecular mechanism for the one‐step assembling process. By addressing this issue, the parallelism in the phase behavior of BCP micelles and inorganic nanoparticles is highlighted, the underlying physical processes of which could be suggested as a one‐step assembly principle for hierarchical superstructures beyond the previously reported multistep methods.