Changing profile of GAD and IA-2 antibody positivity in Indian children with recently diagnosed type 1 diabetes mellitus

Introduction. Published literature on type 1 diabetes (T1DM) patients from India suggests that a substantial number of them are negative to GAD 65 and IA-2 an­tibodies. Antibody positivity rates have been linked to dietary and socio-economic factors and more recently, to changes in the enterobiome. Our anecdotal evidence indicated that antibody positivity rates among newly diagnosed T1DM children were rising. In this presen­tation we have formally collated our data on these antibodies, a first, we believe, in the Indian pediatric population. Material and methods. T1DM was diagnosed by stand­ard clinical criteria advocated by American Diabetes Association including in all patients, the presence of diabetic ketoacidosis (DKA). We used plasma blood glucose rather than A1C to diagnose the acute onset of type 1 diabetes in individuals with symptoms of hy­perglycemia. All patients with this diagnosis had GAD (glutamic acid decarboxylase) and IA-2 (insulinoma antigen 2) antibodies measured as a routine procedure from 2007. Data on patients between the ages of 1 and 16 years as on 31st August 2016 were collected for this study. The antibodies were measured by standard RIA kits from the same manufacturer and performed in the endocrinology laboratory of one of the institutions. Results. We included 694 T1DM cases from 2007 till 2016, out of which 296 were antibody positive. A total of 172 were GAD antibody positive, 62 were IA-2 anti­body positive and 90 exhibited dual antibody positivity (GAD positive + IA-2 positive). The chi-square test for trend analysis showed a significant rising trend for IA-2 antibody alone positive (p < 0.001, chi-square for trend = 17.437, df = 1) and either antibody positive percentages (p < 0.001, chi-square for trend = 22.71, df = 1), but not in the GAD antibody positivity (p = 0.059, chi-square for trend = 3.567, df = 1) and in dual antibody positive percentages (p = 0.486, chi-square for trend = 0.485, df = 1) over a period of 9 years i.e. from 2007 to 2016. Conclusion. Antibody positivity rates in recently di­agnosed T1DM children have changed fairly rapidly over the last nine years. This surge in autoimmunity may also be a significant contributing factor towards the recent increased incidence of T1DM in India

Ultrafast dynamics of excitons in semiconductor quantum dots on a plasmonically active nano-structured silver film

The excited state dynamics of core-shell type semiconductor quantum dots (QDs) of various sizes in close contact with a plasmonically active silver thin film has been demonstrated by using picosecond resolved fluorescence spectroscopy. The non-radiative energy transfer from the QDs to the metal surface is found to be of Föster resonance energy transfer (FRET) type rather than the widely expected nano-surface energy transfer (NSET) type. The slower rate of energy transfer processes compared to that of the electron transfer from the excited QDs to an organic molecule benzoquinone reveals an insignificant possibility of charge migration from the QDs to the metallic film

Broad-Band Activatable White-Opsin

The authors would like to thank C. Cote and K. Dhakal (UTA) for help during initiation of the project. SM would like to thank K. Deisseroth (Stanford University) for ChR2 and C1V1 plasmids, and J. Lin (UCSD) for the ReaChR construct.Currently, the use of optogenetic sensitization of retinal cells combined with activation/inhibition has the potential to be an alternative to retinal implants that would require electrodes inside every single neuron for high visual resolution. However, clinical translation of optogenetic activation for restoration of vision suffers from the drawback that the narrow spectral sensitivity of an opsin requires active stimulation by a blue laser or a light emitting diode with much higher intensities than ambient light. In order to allow an ambient light-based stimulation paradigm, we report the development of a ‘white-opsin’ that has broad spectral excitability in the visible spectrum. The cells sensitized with white-opsin showed excitability at an order of magnitude higher with white light compared to using only narrow-band light components. Further, cells sensitized with white-opsin produced a photocurrent that was five times higher than Channelrhodopsin-2 under similar photo-excitation conditions. The use of fast white-opsin may allow opsin-sensitized neurons in a degenerated retina to exhibit a higher sensitivity to ambient white light. This property, therefore, significantly lowers the activation threshold in contrast to conventional approaches that use intense narrow-band opsins and light to activate cellular stimulation.Yeshttp://www.plosone.org/static/editorial#pee

An improved microfluidics approach for monitoring real-time interaction profiles of ultrafast molecular recognition

Our study illustrates the development of a microfluidics (MF) platform combining fluorescence microscopy and femtosecond/picosecond-resolved spectroscopy to investigate ultrafast chemical processes in liquid-phase diffusion-controlled reactions. By controlling the flow rates of two reactants in a specially designed MF chip, sub-100 ns time resolution for the exploration of chemical intermediates of the reaction in the MF channel has been achieved. Our system clearly rules out the possibility of formation of any intermediate reaction product in a so-called fast ionic reaction between sodium hydroxide and phenolphthalein, and reveals a microsecond time scale associated with the formation of the reaction product. We have also used the developed system for the investigation of intermediate states in the molecular recognition of various macromolecular self-assemblies (micelles) and genomic DNA by small organic ligands (Hoechst 33258 and ethidium bromide). We propose our MF-based system to be an alternative to the existing millisecond-resolved “stopped-flow” technique for a broad range of time-resolved (sub-100 ns to minutes) experiments on complex chemical/biological systems

Zmiana profilu seropozytywności w odniesieniu do przeciwciał anty-GAD i IA2 u indyjskich dzieci z niedawno rozpoznaną cukrzycą typu 1

  Wstęp. Publikacje dotyczące chorych na cukrzycę typu 1 (T1DM) w Indiach sugerują, że u znacznego odsetka tych chorych uzyskuje się ujemne wyniki oznaczeń przeciwciał anty-GAD65 i anty-IA2. Częstość wystę­powania przeciwciał wiązano z czynnikami dietetycz­nymi i społeczno-ekonomicznymi, a ostatnio także ze zmianami mikrobiomu jelitowego. Dane anegdotyczne wskazywały, że w ostatnim czasie nastąpiło zwiększe­nie wskaźników seropozytywności wśród dzieci z nowo rozpoznaną T1DM. W niniejszej prezentacji autorzy po raz pierwszy dokonali zestawienia danych na temat tych przeciwciał w populacji pediatrycznej w Indiach. Materiał i metody. U wszystkich chorych, w tym u osób z cukrzycową kwasicą ketonową (DKA), T1DM rozpozna­wano na podstawie standardowych kryteriów klinicz­nych zalecanych przez American Diabetes Association. Ostry początek cukrzycy typu 1 u osób z objawami hi­perglikemii stwierdzano na podstawie stężenia glukozy w osoczu, a nie odsetka HbA1c. U wszystkich chorych z takim rozpoznaniem oznaczano przeciwciała przeciw dekarboksylazie kwasu glutaminowego (GAD) i przeciw fosfatazie tyrozyny (IA2), co jest rutynową procedurą od 2007 roku. W badaniu wykorzystano dane dotyczą­ce pacjentów w wieku 1–16 lat na dzień 31 sierpnia 2016 roku. Pomiar miana przeciwciał wykonano za pomocą standardowych zestawów RIA tego samego producenta w laboratorium endokrynologicznym jednego z ośrodków. Wyniki. Do badania włączono 694 przypadki T1DM z lat 2007–2016, spośród których 296 było seropozytyw­nych. U 172 osób stwierdzono przeciwciała anty-GAD, u 62 — przeciwciała IA2, a u 90 osób dodatnie były oznaczenia obu rodzajów przeciwciał (dodatni wynik GAD + IA2). W analizie trendów za pomocą testu chi­-kwadrat w okresie 10 lat, tj. od 2007 do 2016 roku, wykazano istotny trend wzrostowy częstości dodat­niego wyniku wyłącznie przeciwciała IA2 (p < 0,001; chi-kwadrat dla trendu = 17,43; df = 1) oraz dodat­niego wyniku oznaczenia jednego z dwóch rodzajów przeciwciał (p < 0,001; chi-kwadrat dla trendu = 22,71; df = 1), nie stwierdzono natomiast istotnych tendencji wzrostowych częstości występowania przeciwciał prze­ciw GAD (p = 0,059; chi-kwadrat dla trendu = 3,567; df = 1) ani obu przeciwciał jednocześnie (p = 0,486; chi-kwadrat dla trendu = 0,485; df = 1). Wnioski. Wskaźniki seropozytywności u dzieci z nie­dawno rozpoznaną T1DM zmieniły się dość szybko w ciągu ostatnich dziewięciu lat. Ten wzrost autoimmunizacji może również być istotnym czynnikiem przyczyniającym się do zwiększonej częstości wystę­powania T1DM, obserwowanej w ostatnim czasie w Indiach

Ultrafast electron transfer in the recognition of different DNA sequences by a DNA-binding protein with different dynamical conformations

<div><p>Ultrafast electron transfer (ET) phenomenon in protein and protein–DNA complex is very much crucial and often leads to the regulation of various kinds of redox reactions in biological system. Although, the conformation of the protein in protein–DNA complex is concluded to play the key role in the ET process, till date very little evidences exist in the literature. λ-repressor–operator DNA interaction, particularly O_R1 and O_R2, is a key component of the λ-genetic switch and is a model system for understanding the chemical principles of the conformation-dependent ET reaction, governed by differential protein dynamics upon binding with different DNA target sequences. Here, we have explored the photoinduced electron transfer from the tryptophan moieties of the protein λ-repressor to two operators DNA of different sequences (O_R1 and O_R2) using picosecond-resolved fluorescence spectroscopy. The enhanced flexibility and different conformation of the C-terminal domain of the repressor upon complexation with O_R1 DNA compared to O_R2 DNA are found to have pronounced effect on the rate of ET. We have also observed the ET phenomenon from a dansyl chromophore, bound to the lysine residue, distal from the DNA-binding domain of the protein to the operator DNA with a specific excitation at 299 nm wavelength. The altered ET dynamics as a consequence of differential protein conformation upon specific DNA sequence recognition may have tremendous biological implications.</p> </div

Ultrafast dynamics of excitons in semiconductor quantum dots on a plasmonically active nano-structured silver film

The excited state dynamics of core–shell type semiconductor quantum dots (QDs) of various sizes in close contact with a plasmonically active silver thin film has been demonstrated by using picosecond resolved fluorescence spectroscopy. The non-radiative energy transfer from the QDs to the metal surface is found to be of Förster resonance energy transfer (FRET) type rather than the widely expected nano-surface energy transfer (NSET) type. The slower rate of energy transfer processes compared to that of the electron transfer from the excited QDs to an organic molecule benzoquinone reveals an insignificant possibility of charge migration from the QDs to the metallic film

Expression of white-opsin in mammalian cells.

<p>(a) Representative confocal image of a white-opsin-transfected HEK293 cell without nuclear staining. Scale bar: 5 μm. (b) Confocal fluorescence image of white-opsin transfected live HEK293 cells stained with nuclear staining dye Hoechst 33242. (c) Confocal image of multiple HEK293 cells showing white-opsin expression. Scale bar: 10 μm. (d) Reporter fluorescence intensity along lines across representative cells (shown in c, dotted blue lines) showing localized expression of white-opsin at the plasma membrane. a.u. = arbitrary units.</p

Quantitative comparison between broad-band and spectrally-filtered narrow-band optogenetic activation of white-opsin.

<p>(a) Spectra of white-light and spectrally-filtered (not intensity-calibrated) narrow-band lights used for optogenetic activation of white-opsin-expressing cells. Representative inward current responses of white-opsin-sensitized HEK293 cells stimulated by (b) white, (c) blue, (d) green and (e) red light. The white light power is fixed and then spectrally-filtered (lower powers for the narrow band measurements). (f) Measured inward peak-currents for varying spectral excitation of white-opsin-sensitized cells. N = 3 biological replicates (total of five cells, 20 sweeps). Average ± S.D. a.u. = arbitrary units.</p

Spectral-dependent activation of narrow-band ChR2-sensitized cells.

<p>Representative inward current responses of ChR2-sensitized HEK293 cell stimulated by (a) white light, as well as spectrally-filtered blue (b), green (c) and red (d) components, respectively. The white light power is fixed and then spectrally-filtered (lower powers for the narrow band measurements). (e) Measured inward peak-currents for varying spectral excitation of ChR2-sensitized cells. N = 3 biological replicates (total of 4 cells, 18 sweeps). Average ± S.D. An asterisk (*) represents p<0.05 between blue and other experiments (i.e. green and red). No statistical difference was found between green and red experiments. There is a significant statistical difference between white and other experiments (red, blue and green) (^#p<0.01). (f) Comparison of representative white light-induced inward currents in a ChR2-expressing HEK293 cell (blue) with a cell expressing white-opsin (gray) at same light intensity. WO: white-opsin.</p