Age-related morphology and function of human arterial endothelial cells

Endothelialization of cardiovascular implants is regarded as a promising strategy for long-term compatibility. While umbilical vein endothelial cells are typically applied in research, human arterial endothelial cells (HAEC) from elderly donors would be the obvious source for autologous cellularization strategies.In our approach, HAEC from 16 donors of varying age (16-63 years) were divided into two groups (<30 years and >30 years) and analyzed regarding morphology, viability, proliferation, function and senescence status.No age-related differences were found regarding morphology, viability, density, prostacyclin and nitrite secretion or collagen and laminin production. However, the metabolic activity was slightly decreased (p = 0.0374) and the membrane integrity marginally impaired (p = 0.0404) in cells from older donors. Two out of three senescence assays detected more senescence markers in cells from older donors.According to the assays applied here, HAEC from young and elderly donors up to the age of 63 years could be judged equally suitable for autologous cellularization strategies. However, this finding should be regarded with caution due to the extremely large variability between individual donors. Further studies comprising a larger sample size are necessary to investigate this issue more thoroughly.

Barriers affecting adherence to radiation treatment and strategies to overcome those barriers

BACKGROUND

The WHO defines adherence as the extent to which a patient's behavior coincides with recommendations from a health-care provider. Nonadherence to cancer treatment has a major impact on the therapeutic outcome.

AIM OF THE STUDY

To assess the prevalence of nonadherence to radiation regimen and to analyze the factors that affect adherence to cancer treatment.

MATERIALS AND METHODS

Patients receiving radiation treatment in our hospital were screened for adherence to appointment keeping and to the prescribed radiation regimen and patients who had unplanned treatment breaks during treatment were interviewed. Between January and July 2013, we identified 61 patients who had unplanned breaks during treatment. We analyzed the social, emotional, educational, economic, and therapeutic barriers that led to nonadherence.

RESULTS

Of the 61 patients who had unplanned breaks during treatment, 54% were males and 46% were females. Fifty-seven percent of patients had head and neck cancers and 25% had gynecological cancers. Seventy-one percent of patients were planned for concurrent chemoradiation. The number of days of unplanned treatment breaks ranged from 3 to 27 days. Social and therapeutic barriers were found to be the most common factor that led to nonadherence in these patients.

CONCLUSION

Identification of barriers that lead to nonadherence, designing strategies to overcome such barriers and effective communication becomes imperative to ensure uninterrupted treatment. Based on the above analysis, we have designed several strategies to improve adherence to treatment among our patients.

Source speciation resolving hydrochemical complexity of coastal aquifers

There is a growing concern of seawater intrusion to freshwater aquifers due to groundwater overexploitation in the eastern coastal belt of Southern India. The problem becomes complex in the regions where industrial effluents are also contaminating the freshwater aquifers. In order to understand the hydrochemical complexity of the system, topographic elevation, static water level measurements, major ion chemistry, ionic cross plots, water type contours and factor analysis were applied for 144 groundwater samples of shallow and deep sources from Quaternary and Tertiary coastal aquifers, located within the industrial zone of 25 km(2) area near Cuddalore, Southern India. The ionic cross plots indicates dissolution of halite minerals from marine sources and seawater mixing into inland aquifers up to the level of 9.3%. The factor analysis explains three significant factors totaling 86.3% of cumulative sample variance which includes varying contribution from marine, industrial effluent and freshwater sources.

Hydrochemical analysis to evaluate the seawater ingress in a small coral island of India

The sustainable development of the limited groundwater resources in the tropical island requires a thorough understanding of detail hydrogeological regime including the hydrochemical behavior of groundwater. Detail analysis of chemical data of groundwater helps in assessing the different groundwater zone affected by formation as well as sea water. Groundwater and saline water interaction is better understood using groundwater major ion chemistry over an island aquifer. Multivariate methods to analyze the geochemical data are used to understand geochemical evolution of groundwater. The methods are successfully used to group the data to evaluate influence of various environs in the study area. Various classification methods such as piper, correlation method, and salinity hazard measurements are also employed to critical study of geochemical characteristics of groundwater to identify vulnerable parts of the aquifer. These approaches have been used to successfully evaluate the aquifer zones of a tiny island off the west coast of India. The most part of island is found to be safe for drinking, however some parts of island are identified that are affected by sea water ingress and dissolution of formation minerals. The analysis has successfully leaded to identification of that part of aquifer on the island which needs immediate attention for restoration and avoids further deterioration.

Laparoscopic assisted anorectal pull through: Reformed techniques

AIM

To assess the modifications in the technique of laparoscopic assisted anorectal pull through (LAARP) practiced at our institute and analyze the post operative outcome and associated complications.

MATERIALS AND METHODS

A retrospective study from January 2001 to May 2009 analyzing LAARP for high anorectal malformations.

RESULTS

A total of 40 patients - 34 males and six females, in the age group of two months to six years were studied. Staged procedure was done in 39 patients; one child with recto vestibular fistula underwent single stage procedure. All the patients withstood surgery well. One patient required conversion due to problems in gaining enough length for the distal rectum in a patient with rectovesical fistula so colostomy was closed and re-located at a proximal splenic flexure. The complications were mucosal prolapse (six cases), anal stenosis (three), adhesive obstruction (two), distal rectal necrosis (one), and urethral diverticulum (one). The patients were followed up with clinical evaluation and continence scoring. The progress has been satisfactory and weight-gain is adequate.

CONCLUSIONS

THE ADVANTAGES OF THE REFORMED TECHNIQUES ARE AS FOLLOWS: Transcutaneous bladder stitch provides excellent visualization; traction over the fistula helps in dissection of the puborectalis, dividing the fistula without ligation is safe, railroading of Hegar's dilators over the suction canula creates adequate pull through channel, saves time and makes procedure simpler with reproducible comparable reports.

Minimally invasive pediatric surgery: Our experience

Aim:

Departmental survey of the pediatric laparoscopic and thoracoscopic procedures.

Materials and Methods:

It is a retrospective study from January 1999 to December 2007. The various types of surgeries, number of patients, complications and conversions of laparoscopic and thoracoscopic procedures were analyzed.

Results:

The number of minimally invasive procedures that had been performed over the past 9 years is 734, out of which thoracoscopic procedures alone were 48. The majority of the surgeries were appendicectomy (31%), orchiopexy (19%) and diagnostic laparoscopy (16%). The other advanced procedures include laparoscopic-assisted anorectoplasty, surgery for Hirschprung’s disease, thoracosocpic decortication, congenital diaphragmatic hernia repair, nephrectomy, fundoplication, etc. Our complications are postoperative fever, bleeding, bile leak following choledochal cyst excision and pneumothorax following bronchogenic cyst excision. A case of empyema thorax following thoracoscopic decortication succumbed due to disseminated tuberculosis. Our conversion rate was around 5% in the years 1999 to 2001, which has come down to 3% over the past few years. Conversions were for sliding hiatus hernia, nephrectomy, perforated adherent appendicitis, Meckel’s diverticulum, thoracoscopic decortication and ileal perforation.

Conclusion:

The minimally invasive pediatric surgical technique is increasingly accepted world wide and the need for laparoscopic training has become essential in every teaching hospital. It has a lot of advantages, such as less pain, early return to school and scarlessness. Our conversion rate has come down from 5% to 3% with experience and now we do more advanced procedures with a lower complication rate.

Preparation of organic-inorganic composite anion-exchange membranes via aqueous dispersion polymerization and their characterization

Organic-inorganic composite membranes based on poly(vinyl alcohol)/SiO(2) were prepared via an aqueous dispersion polymerization route and anion-exchange groups were introduced in the membrane matrix by the chemical grafting of 4-vinylpyridine with the desired content. These membranes were extensively characterized for their surface morphology, thermal stability, water content, and surface-charge properties using SEM, TEM, FTIR, TGA, water uptake, and ion-exchange capacity measurements. Counterion transport numbers across these membranes were estimated from membrane potential data. Membrane conductance measurements were also performed and these data were used for the estimation of values of counterion diffusion coefficients in the membrane phase. Physicochemical and electrochemical properties of these membranes and equivalent pore radius (estimated from electroosmotic flux measurements) were found to be highly dependent on the 4-vinylpyridine (4-VP) content in the membrane phase. It was also observed that for better selectivity and membrane conductivity of anion-exchange membranes complete optimization of the loading of 4-VP in the membrane phase is necessary. Furthermore, among these, membrane with 25% loading with 4-VP exhibited very good selectivity, water content, and ion-exchange capacity along with moderate membrane conductivity, which may be used for their application in electro-driven separation at elevated temperatures or for other electrochemical processes.

Improved measurement of the form factors in the decay lambda+c-->lambda + nue

Using the CLEO detector at the Cornell Electron Storage Ring, we have studied the distribution of kinematic variables in the decay lambda(+)(c)lambda--> e(+)nu(e). By performing a four-dimensional maximum likelihood fit, we determine the form factor ratio, R= f(2)/f(1) = -0.31 +/- 0.05(stat) +/- 0.04(syst), the pole mass, M(pole) = [2.21 +/- 0.08(stat) +/- 0.14(syst)] GeV/c(2), and the decay asymmetry parameter of the lambda(+)(c), alpha (lambda(c)) = -0.86 +/-0.03(stat) +/- 0.02(syst), for q(2) = 0.67 (GeV/c(2))(2). We compare the angular distributions of the lambda(+)(c) and lambda(-)(c) and find no evidence for CP violation: A(lambda(c)) = (alpha(lambda(c)) + alpha (lambda(c)))/(alpha(lambda(c))-alpha(lambda(c))) = 0.00 +/- 0.03(stat) +/- 0.01(syst) +/- 0.02, where the third error is from the uncertainty in the world average of the CP-violating parameter, A(lambda), for ppi(-).

Preparation and electrochemical characterization of cation- and anion-exchange/polyaniline composite membranes

Composite membranes were prepared by chemical polymerization of a thin layer of polyaniline (PANI) in the presence of a high oxidant concentration on a single face of a sulfonated cation-exchange membrane (CEM) and quaternary aminated anion-exchange membrane (AEM). IR and SEM studies for both types of membranes confirmed PANI loading on the ion-exchange membranes. PANI composite ion-exchange membranes were characterized as a function of the polymerization time by ion-exchange capacity, coating density, and membrane conductance measurements. Membrane potential measurements were performed in various electrolyte solutions in order to observe the selectivity of these membranes for different types of counterions. Membrane potential data in conjunction with membrane conductance data was interpreted on the basis of frictional considerations between membrane matrix and solute. Electrodialysis experiments, using PANI composite ion-exchange membranes with 4 h polymerization time, were performed in single and mixed electrolyte solutions for observing electromigration of solute across PANI composite ion-exchange membranes. Relative dialytic rates of Na(2)SO(4), CaCl(2), and CuCl(2) were estimated with reference to NaCl on the basis of electrodialysis experiments and it was concluded that it is possible to separate different electrolytes using PANI composite ion-exchange membranes.

Development of urethane acrylate composite ion-exchange membranes and their electrochemical characterization

With the objective of introducing antifouling characteristics into interpolymer types of cation and anion exchange membranes, the surface of these membranes was coated with a 12-microm-thick urethane acrylate layer and was cured by UV radiation of wavelengths 308 and 172 nm under a complete inert atmosphere. Different urethane acrylate composite ion exchange membranes developed were characterized in NaCl solution by measuring their ion-exchange capacity, volume fraction of water, contact angle with water, membrane conductance, and membrane potential. It was found that the electrochemical transport properties of urethane acrylate composite cation-exchange membranes were increased due to resonance stabilization of the urethane group, which acts as a weak acid and dissociates as a negatively charged urethane ion and a positively charged proton. This contributes toward the net charge density of the membrane matrix responsible for enhanced selectivity and conductivity, while for urethane acrylate composite anion-exchange membranes reduction in net charge density was responsible for reduction in electrochemical transport properties. Counterion transport number, permselectivity, and counterion diffusion coefficient values for these membranes were also estimated. Experiments were also carried out in higher homologs of sodium carboxylate solutions in order to observe the fouling tendencies of these membranes. It was concluded that it is possible to obtain antifouling characteristics of ion-exchange membranes by coating and curing thin hydrophilic layers of urethane acrylate on their surfaces without sacrificing their electrochemical transport properties.

Geophysical expression of natural recharge in different geological terrains

Behavior of the Dar-Zarrouk parameters--longitudinal unit conductance, transverse unit resistance, longitudinal resistivity, and transverse resistivity--has been compared with the behavior of the natural recharge in two geological terrains. Contour patterns of the geophysical parameters and those of natural recharge have been analyzed and a qualitative relation in their behavior was recognized. Graphical comparison of the geophysical and hydrogeological parameters clearly illustrates a qualitative relationship between the two parameters. Use of such qualitative relation in the field of ground water exploration and management studies is explained. A modest beginning is attempted to arrive at a quantitative relation between natural recharge and Dar-Zarrouk parameters.

Studies on the electrochemical and permeation characteristics of asymmetric charged porous membranes

Asymmetric charged porous membranes were prepared by imbedding 10% (W/W) ion-exchange resin in cellulose acetate binder. Membrane potential and conductance measurements have been carried out in sodium chloride solutions at different concentrations to investigate the relationship between concentration of fixed charges and electrochemical properties of developed nonselective cation- and anion-exchange membranes. Counterion transport number and permselectivity of these membranes were found to vary due to the presence of ion-exchange resin. The hydrodynamic and electroosmotic permeability of sodium chloride solutions has been studied in order to compute equivalent pore radius. For cation- and anion-exchange membranes good agreement was observed between pore radius values estimated from hydrodynamic and electroosmotic permeability coefficient separately, while for nonselective membranes no correlation was found. Membrane conductance data, along with values of concentration of fixed charges, were used for the estimation of the tortuosity factor, salt permeability coefficient, and frictional coefficient between solute and membrane matrix employing an interpretation by nonequilibrium thermodynamic principles based on frictional forces. Moreover, surface morphological studies of these membranes also have been carried out and the membranes were found to be reasonably homogeneous.

Studies of the effect of variation of blend ratio on permselectivity and heterogeneity of ion-exchange membranes

Heterogeneous ion-exchange membranes (both cationic and anionic types) have been synthesized by solution casting techniques using polyvinyl chloride (PVC) as binder and ion-exchange resin (-300+400 mesh). The binder:resin ratio varied from 60:40 to 30:70. The transport behavior of the membranes has been evaluated chronopotentiometrically in sodium chloride (NaCl) solutions of different concentrations. The different parameters E(0) (potential drop across the membrane at the instant of application of current I), E(max) (maximum potential drop across the membrane after the application of current I), DeltaE (magnitude of the potential jump across the membrane at transition time tau), Itau(1/2), tau, etc., have been evaluated. The isoconductance points were determined and based on the microheterogeneous model proposed by Zabolotsky and Nikonenko (J. Membrane Sci. 79 (1993) 181) the distribution factors beta has been evaluated for both types of ion exchange membranes. The electroconductivity of the joint gel (kappa ) and pure gel phases (kappa ' ) has been determined. At any particular solution concentration the transport number as well as the permselectivity of membranes increases with increased resin content of the membrane. The microheterogeneity factor beta exhibits synchronization among the each set of four different membranes for both the cationic and anionic type.

Studies on Exchange Equilibria of Cations between Cation-Exchange Membranes and Electrolytic Solutions

The variations of the selectivity coefficient K(A)(B) between Na(+)-H(+), Na(+)-K(+), and Na(+)-Cu(2+) systems and the separation factor alpha(A)(B) between Na(+)-Cu(2+) and K(+)-Cu(2+) systems in cation-exchange membranes as functions of loading and particle size of resin have been measured. The exchange affinities of all the membranes increase as H(+)<Na(+)<K(+)<Cu(2+). K(A)(B) is almost constant, independent of particle size and loading of resin in the membrane. Alpha(Na)(Cu) and alpha(K)(Cu) increase with decrease in particle size but remain almost constant with loading of resin in the membranes. The order of selectivity is K(Na)(H)<K(Na)(K)< or =K(Na)(Cu). The values of (alpha(A)(B)Q(0)(-1))(other)(alpha(A)(B)Q(0)(-1))(-1)(M(300)C60) for the Na(+)-Cu(2+) system are approximately 1.060 and for K(+)-Cu(2+) are approximately 0.870. Q(0) represents the exchange capacity of a dry membrane per unit volume (in milliequivalents per cubic centimeter).

Dpp and Hedgehog mediate neuron-glia interactions in Drosophila eye development by promoting the proliferation and motility of subretinal glia

Neuron-glia interactions are crucial for the establishment of normal connectivity in the nervous system during development, but the molecular signals involved in these interactions are largely unknown. Here we show that differentiating photoreceptors in the developing Drosophila eye influence the proliferative and migratory behavior of the subretinal glia through the diffusible factors Decapentaplegic (Dpp) and Hedgehog (Hh). We demonstrate that proliferation and migration of the glia are separable processes, and that Dpp promotes both the proliferation and motility of the glia, whereas Hh appears to promote only their motility; neither specifies the direction of migration. We present evidence that Dpp and Hh act on the glia in parallel and through the regulation of transcription. Finally, we show that ectopic migration of subretinal glia can result in the ectopic projection of photoreceptor axons. Our study suggests a novel function for Hh in regulating migratory behavior and provides further evidence for a complex mutual dependence between glial and neuronal cells during development.

Solution-Membrane Equilibrium at Metal-Deposited Cation-Exchange Membranes: Chronopotentiometric Characterization of Metal-Modified Membranes

Copper- and lead-deposited interpolymer cationic membranes have been prepared by electroless plating by an ion-exchange method and characterized by chronopotentiometry and cyclic voltammetry. The parameters such as transition time (tau), Itau1/2, the potential drop (E0) across these membranes immediately after the application of constant current (I), and the height of the potential jump (DeltaE) across the membrane at tau have been measured by chronopotentiometry and compared with those of plain membranes. The approximate percentage of metal coverage and the number of ionic sites masked by the deposited metal in terms of NaCl concentration have been estimated from the differences in Itau1/2 values of plain and metal-deposited membranes. The quantity of metal deposited in a unit area of the membrane surface was measured by differential pulse polarography. The oxidation and reduction peak potentials corresponding to Cu(0)/Cu(II) and Pb(0)/Pb(II) couples were identified by cyclic voltammetry at pH 2.8 and 4.5 of 0.2 M CH3COONa-H2SO4. Copyright 1999 Academic Press.

Migration and function of glia in the developing Drosophila eye

Although glial cells have been implicated widely in the formation of axon tracts in both insects and vertebrates, their specific function appears to be context-dependent, ranging from providing essential guidance cues to playing a merely facilitory role. Here we examine the role of the retinal basal glia (RBG) in photoreceptor axon guidance in Drosophila. The RBG originate in the optic stalk and have been thought to migrate into the eye disc along photoreceptor axons, thus precluding any role in axon guidance. Here we show the following. (1) The RBG can, in fact, migrate into the eye disc even in the absence of photoreceptor axons in the optic stalk; they also migrate to ectopic patches of differentiating photoreceptors without axons providing a continuous physical substratum. This suggests that glial cells are attracted into the eye disc not through haptotaxis along established axons, but through another mechanism, possibly chemotaxis. (2) If no glial cells are present in the eye disc, photoreceptor axons are able to grow and direct their growth posteriorly as in wild type, but are unable to enter the optic stalk. This indicates that the RBG have a crucial role in axon guidance, but not in axonal outgrowth per se. (3) A few glia close to the entry of the optic stalk suffice to guide the axons into the stalk, suggesting that glia instruct axons by local interaction.

The netrin receptor frazzled is required in the target for establishment of retinal projections in the Drosophila visual system

Retinal axons in Drosophila make precise topographic connections with their target cells in the optic lobe. Here we investigate the role of the Netrins and their receptor Frazzled in the establishment of retinal projections. We find that the Netrins, although expressed in the target, are not required for retinal projections. Surprisingly, Frazzled, found on both retinal fibers and target cells, is required in the target for attracting retinal fibers, while playing at best a redundant role in the retinal fibers themselves; this finding demonstrates that target attraction is necessary for topographic map formation. Finally, we show that Frazzled is not required for the differentiation of cells in the target. Our data suggest that Frazzled does not function as a Netrin receptor in attracting retinal fibers to the target; nor does it seem to act as a homotypic cell adhesion molecule. We favor the possibility that Frazzled in the target interacts with a component on the surface of retinal fibers, possibly another Netrin receptor.

Somatosensory stimulus entrains spindle oscillations in the thalamic VPL nucleus in barbiturate anesthetized rats

This study reports the effect of external stimuli on spindle oscillations in the somatosensory thalamus of barbiturate anesthetized rats. Multi-unit responses to somatosensory stimuli were measured from the contralateral thalamic ventral posterior lateral (VPL) nucleus at different stimulus strengths and periods. Spindle oscillations could be entrained by the somatosensory stimuli at periods between 2 and 5 s. A resonance phenomenon described as a quiescent pre-stimulus period followed by entrained post-stimulus oscillations, was observed for somatosensory stimuli above the threshold for eliciting cortical evoked potentials and a stimulus period between 2 and 5 s. This study demonstrates an ascending pathway for localized modulation of spindle oscillations.

Molecular cloning and developmental expression of a zebrafish axonal glycoprotein similar to TAG-1

TAG-1 is a mammalian cell adhesion molecule of the immunoglobulin superfamily that is expressed transiently by a subset of neurons and serves as a fertile substrate for neurite outgrowth in vitro (Furley, A.H., Morton, S.B., Manalo, D., Karagogeos, S., Dodd, H., Jessell, T.M., 1990 The axonal glycoprotein TAG-1 is an immunoglobulin superfamily member with neurite outgrowth promoting activity. Cell 61, 157-170). In order to examine the in vivo function of this molecule, we have cloned a zebrafish tag1-like cDNA and analyzed its expression patterns. tag1 Is expressed transiently by specific subsets of neurons when they are projecting their axons or when they are migrating. The specific and dynamic pattern of expression of zebrafish tag1 is consistent with its proposed role in axon guidance and cell migration.

In vivo nitric oxide sensor using non-conducting polymer-modified carbon fiber

Nitric oxide (NO) is emerging as a very important and ubiquitous gaseous messenger in the body. The response characteristics of NO sensors made of non-conducting polymer modified carbon fiber electrodes are investigated to determine their selectivity, sensitivity, and stability for in vivo use. A composite polymer, comprising Nafion, m-phenylenediamine, and resorcinol, showed the best selectivity and stability to amperometric NO detection. The non-conducting, self-limiting polymer film protects the electrode from interference and fouling by other biochemicals. Although the relative sensitivity to NO of the modified sensor is lower than that of the unmodified carbon fiber electrodes (less than 6%), the composite polymer electrode showed high selectivity against ascorbic acid (> 2000:1), nitrite (> 600:1), and dopamine (> 200:1). The stability of the NO sensor was maintained for at least 1 week. The NO sensitivity after in vivo experiments (n = 8) is 88.1 +/- 5.6% of initial sensitivity data obtained before in vivo experiments. Preliminary in vivo experiments done with this electrode are shown to capture elevated NO levels in brain following an ischemic injury.

Clinical profile of acute myocardial infarction in women

Three hundred fifty women with acute myocardial infarction who formed 17% of total myocardial infarction cases admitted were studied. Only 7.7% were below 40 years. Infarction occurred mostly (80%) in postmenopausal period. History of previous illness was present in 73% cases. Risk factors were present in majority (75%) of the cases. Common risk factors in Indian women were hypertension in 49% cases and diabetes mellitus in 34% cases. None were using oral contraceptives and it occurred mostly (77%) in multiparous women. Majority (94%) presented with typical chest pain. Premonitory symptoms occurred in only a few patients (14%). Complications occurred more frequently in 40% cases. Mortality rate appears to be high (18%); the commonest cause being cardiogenic shock.

Chloride channel block phase advances the single-unit activity rhythm in the SCN

The mammalian suprachiasmatic nuclei (SCN) contain a circadian pacemaker that exhibits a 24 h rhythm in single-unit activity in vivo and in vitro. Chloride channel block by a saturating concentration of picrotoxin at either CT6 or CT15 produces large phase advances in the SCN single-unit activity rhythm in vitro. These phase advances are not affected by simultaneous blockade of voltage-sensitive sodium and calcium channels by TTX and magnesium. Thus, the effects of picrotoxin appear to be mediated by direct blockade of the chloride channel, rather than subsequent membrane depolarization. GABA-A receptor-mediated chloride flux may be part of the mechanism of circadian timekeeping.