Study on the association and phase separation behavior of surfactants and promethazine hydrochloride: impact of ammonium electrolytes.

In the current study, the association and phase separation of cationic tetradecyltrimethylammonium bromide (TTAB) and nonionic Triton X-100 (TX-100) surfactants with promethazine hydrochloride (PMH) were investigated in aqueous ammonium-based solutions. The micellization nature of the TTAB and PMH drug mixture was examined by evaluating critical micelle concentration (CMC) and counterion binding extent (ß) at different salt contents and temperatures (298.15-323.15 K). Micelle formation in the TTAB + PMH mixture was enhanced in the presence of ammonium salts, whereas the process was delayed with an increase in temperature in the respective salt solution. With an increase in salt content, the cloud point (CP) of the TX-100 + PMH mixture decreased, which revealed that the respective progression occurred through the salting out phenomenon. In micellization and clouding processes, the changes in free energies ΔG0m and ΔG0c were found to be negative and positive, respectively, demonstrating that the corresponding processes are spontaneous and non-spontaneous. Standard enthalpies (ΔH0m/ΔH0c) and standard entropies (ΔS0m/ΔS0c) for the association and clouding processes, respectively, were also calculated and discussed. The core forces amid TTAB/TX-100 and PMH in the manifestation of electrolytes are dipole-dipole and hydrophobic forces among the employed components according to the values for ΔH0m/ΔH0c and ΔS0m/ΔS0c, respectively.

Study of Vitamin D Deficiency among the Apparently Healthy Population in Jashore, Bangladesh.

Globally Vitamin D deficiency is a burning issue for the last two decades. Though the very high prevalence of hypovitaminosis D is worldwide even in the South-East Asia but there is very limited data in Bangladesh. This observational study was designed to assess the status of Vitamin D deficiency among the clinically apparent healthy population in the district of Jessore, Bangladesh from January 2017 to June 2017. Both the male and female clinically healthy participants between the age of 10 and 70 years residing more than 3 years in Jashore were included in this study, while those having renal or liver failure or any other chronic diseases and using drugs that could potentially interfere the metabolism of vitamin D were excluded from the study. Here we leveled serum 25(OH)D concentration of ≤20ngm/dl as deficient, >20-30ngm/dl graded as insufficient and >30ngm/dl graded as sufficient. Among 160 participants 43.1% (n=69) were male and 56.9% (n=91) were female. And 102(63.7%) participants had deficient vitamin D, 50(31.3%) had insufficient vitamin D and only 8(5%) had sufficient vitamin D. The mean serum 25(OH)D levels in our study was 18.60±6.59ngm/dl. The mean serum 25(OH)D level in case of male participants was 19.72±7.10ngm/dl whereas in female the corresponding figure was 17.74±6.07gm/dl and no significant difference observed among the man and women (p=0.059). Sun exposure play a vital role in the vitamin D deficiency and we observed only 1-2 hours/day sun exposure was sufficient for normal vitamin D level (p=0.001). In case of women who used veil had significantly lower level of vitamin D (p=<0.001) due to lack of adequate sun exposure. Urban participants who also had significant low level of vitamin D due to the same reason (p=0.009). There was no deficiency observed in farmers and only 5(3.1%) had insufficient vitamin D. No significant difference observed in deficiency of vitamin D among the different age, sex, education level, skin complexion or BMI. But the obese participants had significant (p=0.041) lower vitamin D level. It was concluded with the high rate of vitamin D deficiency in this small scale study conducting in a district of Bangladesh demands a nationwide survey of vitamin D.

Photoinduced electron transfer of zinc porphyrin-oligo(thienylenevinylene)-fullerene[60] triads; thienylenevinylenes as efficient molecular wires.

Two novel donor-bridge-acceptor arrays (ZnP-nTV-C60) with zinc porphyrin (ZnP) and fullerene (C60), covalently connected by oligo(thienylenevinylene) (nTV) molecular wires (n = 3 and 8; ), have been prepared in a multistep convergent manner. The influence of the nTV-length on the electrochemical and electronic properties of the ZnP-nTV-C60 triads has been revealed. Interestingly, an efficient photoinduced electron transfer process occurs in both triads with formation of intermediate radical-ion pairs (namely, ZnP˙(+)-nTV-C60˙(-) and ZnP-nTV˙(+)-C60˙(-)) as confirmed by the nanosecond transient absorption measurements in the visible and NIR regions. In polar and nonpolar solvents, the rate constants of charge-separation processes (kCS) via(1)ZnP*-nTV-C60 were found to decrease from ca. 1.2 × 10(10) s(-1) for n = 3 (RDA = 20 Å) to (5-7) × 10(9) s(-1) for n = 8 (RDA = 60 Å) on the basis of fluorescence lifetime measurements of the ZnP moiety. From these data, together with those previously obtained ones for n = 4 in the related ZnP-nTV-C60 systems, a low attenuation coefficient was evaluated for the nTV molecular wires.

A case of swallowed surprising foreign bodies in a young psychotic man.

Here we present a case of a young psychotic man who presented with chronic abdominal pain without clear history of foreign body (FB) ingestion. On examination patient was euphoric in mood, mildly anaemic & dehydrated from repeated vomiting. Abdomen was tender and rigid in epigastrium with no visible or palpable swelling. Routine hematology and biochemistry being normal, visible & echognic FBs were found on plain x-ray abdomen (AP & Lateral views) & USG abdomen. The case was revealed by plain x-ray and ultrasonography of abdomen. Since the foreign bodies swallowed were elongated, sharp edged or pointed and potentially injurious, no attempt was made to get them out by upper GI endoscopy. Their nature was revealed at formal laparotomy and gastrotomy. The patient recovered uneventfully. He was sent for psychiatric follow up.

Photoinduced energy and electron transfer in phenylethynyl-bridged zinc porphyrin-oligothienylenevinylene-C60 ensembles.

Donor-bridge-acceptor triad (Por-2TV-C(60)) and tetrad molecules ((Por)(2)-2TV-C(60)), which incorporated C(60) and one or two porphyrin molecules that were covalently linked through a phenylethynyl-oligothienylenevinylene bridge, were synthesized. Their photodynamics were investigated by fluorescence measurements, and by femto- and nanosecond laser flash photolysis. First, photoinduced energy transfer from the porphyrin to the C(60) moiety occurred rather than electron transfer, followed by electron transfer from the oligothienylenevinylene to the singlet excited state of the C(60) moiety to produce the radical cation of oligothienylenevinylene and the radical anion of C(60). Then, back-electron transfer occurred to afford the triplet excited state of the oligothienylenevinylene moiety rather than the ground state. Thus, the porphyrin units in (Por)-2TV-C(60) and (Por)(2)-2TV-C(60) acted as efficient photosensitizers for the charge separation between oligothienylenevinylene and C(60).

Photoinduced charge-separation and charge-recombination processes of fullerene[60] dyads covalently connected with phenothiazine and its trimer.

Photoinduced charge-separation and charge-recombination processes of fullerene[60] dyads covalently connected with phenothiazine and its trimer (PTZ n -C 60, n = 1 and 3) with a short amide linkage were investigated. A time-resolved fluorescence study provided evidence of charge separation via the excited singlet state of a C 60 moiety ( (1)C 60*), which displayed high efficiencies in various solvents; Phi (S) CS (quantum yield of charge separation via (1)C 60*) = 0.59 (toluene) to 0.87 (DMF) for PTZ 1-C 60 and 0.78 (toluene) to 0.91 (DMF) for PTZ 3-C 60. The transient absorption measurement with a 6 ns time resolution in the visible and near-IR regions showed evidence of the generation of radical ion pairs in relatively polar solvents for both dyads. In nonpolar toluene, only PTZ 1- (3)C 60* was observed for PTZ 1-C 60, whereas PTZ 3- (3)C 60* as well as the radical ion pair state in equilibrium were observed for PTZ 3-C 60. The radical ion pairs had relatively long lifetimes: 60 (DMF) to 910 ns ( o-dichlorobenzene) for (PTZ) 1 (*+)-C 60 (*-) and 230 (PhCN) to 380 ns ( o-dichlorobenzene) for (PTZ) 3 (*+)-C 60 (*-). The small reorganization energy (lambda) and the electronic coupling element (| V|) were estimated by the temperature dependence of the charge-recombination rates, i.e., lambda = 0.53 eV and | V| = 1.6 cm (-1) for (PTZ) 3 (*+)-C 60 (*-).

Through-bond excited energy transfer mediated by an amidinium-carboxylate salt bridge in Zn-porphyrin free-base porphyrin dyads.

Excited energy-transfer processes were investigated for a supramolecular Zn-porphyrin free-base porphyrin dyad, ZnPA-2 x FbPC-2, in which beta-octaalkylated meso-diarylporphyrins are connected through an amidinium-carboxylate salt bridge. The rate of energy transfer in the dyad (1.3 x 10(9) s(-1)) is substantially slower than that in the previously reported dyad, ZnPA-1FbPC-1 (4.0 x 10(9) s(-1)), in which meso-tetraarylporphyrins are connected through the same amidinium-carboxylate salt bridge. The Förster-type mechanism can explain only minor parts of these rates (3.3 x 10(8) and 5.1 x 10(8) s(-1), respectively). Thus, Dexter-type through-bond energy transfer may be invoked. Indeed, bridge-mediated electronic processes would be favored in ZnPA-1 x FbPC-1 over ZnPA-2 x FbPC-2 on the basis of steric and electronic factors. Sterically, the phenyl groups in ZnPA-2 and FbPC-2 are more closely perpendicular to the porphyrin planes than those in ZnPA-1 and FbPC-1. Electronically, the energy and symmetry of the occupied frontier orbitals should favor ZnPA-1 x FbPC-1 over ZnPA-2 x FbPC-2 in terms of electronic interactions through the bridge. Therefore, the observed trend (ZnPA-1 x FbPC-1>ZnPA-2 x FbPC-2), consistent with these considerations, lends further support to the through-bond mechanism. Thus, the amidinium-carboxylate salt bridge is effective in mediating through-bond energy transfer even though the bond is noncovalent.

High effectiveness of oligothienylenevinylene as molecular wires in Zn-porphyrin and C60 connected systems.

Photoinduced energy transfer and electron transfer processes have been found between the excited singlet state of Zn-porphyrin and C(60) via an oligothienylenevinylene bridge depending on the length of the oligothiophene and solvent polarity.

Multi-triphenylamine-substituted porphyrin-fullerene conjugates as charge stabilizing "antenna-reaction center" mimics.

A new concept of charge stabilization via delocalization of the pi-cation radical species over the donor macrocycle substituents in a relatively simple donor-acceptor bearing multimodular conjugates is reported. The newly synthesized multimodular systems were composed of three covalently linked triphenylamine entities at the meso position of the porphyrin ring and one fulleropyrrolidine at the fourth meso position. The triphenylamine entities were expected to act as energy transferring antenna units and to enhance the electron donating ability of both free-base and zinc(II) porphyrin derivatives of these pentads. Appreciable electronic interactions between the meso-substituted triphenylamine entities and the porphyrin pi-system were observed, and as a consequence, these moieties acted together as an electron-donor while the fullerene moiety acted as an electron-acceptor in the multimodular conjugates. In agreement with the spectral and electrochemical results, the computational studies performed by the DFT B3LYP/3-21G(*) method revealed delocalization of the frontier highest occupied molecular orbital (HOMO) over the triphenylamine entities in addition to the porphyrin macrocycle. Free-energy calculations suggested that the light-induced processes from the singlet excited state of porphyrins are exothermic in the investigated multimodular conjugates. The occurrence of photoinduced charge-separation and charge-recombination processes was confirmed by the combination of time-resolved fluorescence and nanosecond transient absorption spectral measurements. Charge-separated states, on the order of a few microseconds, were observed as a result of the delocalization of the pi-cation radical species over the porphyrin macrocycle and the meso-substituted triphenylamine entities. The present study successfully demonstrates a novel approach of charge-stabilization in donor-acceptor multimodular conjugates.

Synthesis and photoinduced intramolecular processes of fulleropyrrolidine-oligothienylenevinylene-ferrocene triads.

Two new triads based on N-methylfulleropyrolidine, oligothienylenevinylenes (nTV) and ferrocene (Fc), namely C(60)-nTV-Fc (n=2, 4) have been synthesized. A HOMO-LUMO gap as low as 1.09-1.11 eV was experimentally determined by cyclic voltammetry. In both polar and nonpolar solvents, photoinduced charge-separation (CS) processes in C(60)-nTV-Fc predominantly take place from the singlet excited states of C(60) and nTV; this result was indicated by steady and time-resolved emission spectroscopy. In the case of C(60)-4TV-Fc, the CS state was indicated by the nanosecond transient absorption spectra. In C(60)-2TV-Fc, although the CS process was also confirmed by the fluorescence quenching in nonpolar and polar solvents, the lifetimes of the CS states were shorter than those of C(60)-4TV-Fc. It was revealed that the introduction of Fc donor moiety at the end of the longer nTV chain in the C(60)-nTV dyad systems effectively increases the CS efficiency and the lifetimes of CS states.

Photoinduced electron transfer in a Watson-Crick base-paired, 2-aminopurine:uracil-C60 hydrogen bonding conjugate.

A fluorescent reporter molecule, 2-aminopurine was self-assembled via Watson-Crick base-pairing to a uracil appended fullerene to form a donor-acceptor conjugate; efficient photoinduced charge separation was confirmed by time-resolved emission and transient absorption spectral studies.

Design and studies on supramolecular ferrocene-porphyrin-fullerene constructs for generating long-lived charge separated states.

Supramolecular ferrocene-porphyrin-fullerene constructs, in which covalently linked ferrocene-porphyrin-crown ether compounds were self-assembled with alkylammonium cation functionalized fullerenes, have been designed to achieve stepwise electron transfer and hole shift to generate long-lived charge separated states. The adopted crown ether-alkylammonium cation binding strategy resulted in stable conjugates as revealed by computational studies performed by the DFT B3LYP/3-21G(*) method in addition to the binding constants obtained from fluorescence quenching studies. The free-energy changes for charge-separation and charge-recombination were varied by the choice of different metal ions in the porphyrin cavity. Free-energy calculations suggested that the light-induced electron-transfer processes from the singlet excited state of porphyrins to be exothermic in all of the investigated supramolecular dyads and triads. Photoinduced charge-separation and charge-recombination processes have been confirmed by the combination of the time-resolved fluorescence and nanosecond transient absorption spectral measurements. In case of the triads, the charge-recombination processes of the radical anion of the fullerene moiety take place in two steps, viz., a direct charge recombination from the porphyrin cation radical and a slower step involving distant charge recombination from the ferrocene cation moiety. The rates of charge recombination for the second route were found to be an order of magnitude slower than the former route, thus fulfilling the condition for charge migration to generate long-lived charge-separated states in supramolecular systems.

Formation, spectral, electrochemical, and photochemical behavior of zinc N-confused porphyrin coordinated to imidazole functionalized fullerene dyads.

Donor-acceptor dyads were constructed using zinc N-confused porphyrin (ZnNCP), a structural isomer of zinc tetraphenylporphyrin, as a donor, and fullerene as an electron acceptor. Two derivatives, pyridine-coordinated zinc N-confused porphyrin (Py:ZnNCP) and the zinc N-confused porphyrin dimer (ZnNCP-dimer) were utilized to form the dyads with an imidazole-appended fulleropyrrolidine (C60Im). These porphyrin isomers formed well-defined 1:1 supramolecular dyads (C60Im:ZnNCP) via axial coordination. The dyads were characterized by optical absorption and emission, ESI-mass, 1H NMR, and electrochemical methods. The binding constant, K, was found to be 2.8 x 10(4) M(-1) for C60Im:ZnNCP. The geometric and electronic structure of C60Im:ZnNCP were probed by using DFT B3LYP/3-21G methods. The HOMO was found to be on the ZnNCP entity, while the LUMO was primarily on the fullerene entity. The electrochemical properties of C60Im:ZnNCP was probed using cyclic voltammetry in o-dichlorobenzene, 0.1 n-Bu4NClO4. The Py:ZnNCP was found to be easier to oxidize by over 340 mV compared to Py:ZnTPP. Upon dyad formation via axial coordination, the first oxidation revealed an anodic shift of nearly 90 mV. Evidence of photoinduced charge separation from the singlet excited ZnNCP to the appended fullerene was established from time-resolved emission and nanosecond transient absorption studies.

Downregulation of bactericidal peptides in enteric infections: a novel immune escape mechanism with bacterial DNA as a potential regulator.

Antibacterial peptides are active defense components of innate immunity. Several studies confirm their importance at epithelial surfaces as immediate barrier effectors in preventing infection. Here we report that early in Shigella spp. infections, expression of the antibacterial peptides LL-37 and human beta-defensin-1 is reduced or turned off. The downregulation is detected in biopsies from patients with bacillary dysenteries and in Shigella- infected cell cultures of epithelial and monocyte origin. This downregulation of immediate defense effectors might promote bacterial adherence and invasion into host epithelium and could be an important virulence parameter. Analyses of bacterial molecules causing the downregulation indicate Shigella plasmid DNA as one mediator.

Disease-dependent changes in T-cell populations in patients with shigellosis.

In shigellosis, bacterial infection is associated with an extensive inflammation of the rectal mucosa, resulting in bloody dysentery. The role of T-cell-mediated pro-inflammatory mechanisms has been implicated in this process, but the specific role of T-cell subsets is still not well understood. In this study we attempted to identify the changes in T-cell populations in patients with shigellosis during the disease course. The T-cell subset distribution was analyzed by immunohistochemistry in the rectal mucosa and by immuno-flow cytometry in the peripheral blood. Blood and rectal biopsies were studied from patients with Shigella dysenteriae 1 (n= 11) and S. flexneri (n= 11) infection and 20 healthy age-matched controls. We found an expansion of gammadelta+T cells in the rectal mucosa, but a decrease in the percentage of gammadelta+T cells in the blood in acute shigellosis. There was also a preferential increase in CD8+ T cells in the surface epithelium of rectal tissue in patients infected with S. dysenteriae 1, but not in patients infected with S. flexneri. Our findings suggest that the rectal mucosal inflammation in shigellosis is associated with an expansion of T cells, in particular CD8+ and gammadelta+T-cell subsets in the gut mucosa, which may be of importance for the pathogenesis of shigellosis.

Rapid detection of Vibrio cholerae O139 Bengal from stool specimens by PCR.

In a previous study using pure bacterial cultures in a PCR assay, a primer pair corresponding to a unique chromosomal region of Vibrio cholerae O139 Bengal generated an amplicon from only V. cholerae O139 Bengal. PCR with the same primer pair was used to screen 180 diarrheal stool specimens. All the 67 V. cholerae O139 culture-positive stool specimens were positive by PCR, and the remaining specimens, which contained either other recognized enteric pathogens or no pathogens, were all negative by PCR.

Quantitative assessment of IgG and IgA subclass producing cells in rectal mucosa during shigellosis.

AIMS: To assess quantitatively both the morphological changes in the rectal mucosa and the changes in the relative frequency of IgA and IgG subclass producing cells found in the rectal mucosa during the acute phase of shigellosis and at convalescence. METHODS: Rectal biopsies from 25 Shigella dysenteriae 1 infected patients, 10 Shigella flexneri infected patients, and 40 uninfected controls were studied. Morphological changes in the mucosa were graded. The frequency of IgA and IgG subclass producing cells was assessed. In addition, immunostaining for secretory component in epithelial cells was analysed. RESULTS: Using morphological grading, 20% of the 35 patients studied had advanced inflammation (grade 3) in the acute phase of the disease. At convalescence, grade 1 inflammation was seen in 37% of the patients and in 10% of the controls. In the acute phase, as well as at convalescence, the number of IgA1, IgA2, and IgG2 positive cells was significantly higher than in the controls. The results were related to the histopathological degree of inflammation. CONCLUSIONS: In shigellosis, there is evidence for a prolonged humoral response residing in the mucosa long after the clinical symptoms have resolved, suggesting that shigellosis induces persisting mucosal humoral immune and inflammatory responses, remaining at least until 30 days after the infection.

In situ characterization of inflammatory responses in the rectal mucosae of patients with shigellosis.

Shigella species cause bacillary dysentery in humans by invading epithelial cells of the colonic mucosa leading to colonic epithelial cell destruction and inflammation. For further analysis of local gut inflammation, morphological changes and the potential involvement of mediators in regulatory mechanisms of cell activation and cell proliferation were studied immunohistochemically in rectal mucosal biopsies taken from patients during the acute phase of shigellosis and at convalescence. Rectal biopsies from 25 Shigella dysenteriae-1 and 10 Shigella flexneri-infected patients and from 40 controls were studied. The frequencies of proliferative cells (Ki67-positive cells), p53-immunostaining cells, and cells coexpressing Ki67 with CD3 or with p53 were analyzed. Immunostaining for the inducible nitric oxide synthase (iNOS) and the endothelial NOS was assessed. In addition, the frequencies of apoptotic cells and CD68+ cells that engulf apoptotic cells were assessed. By morphological grading, 20% of the patients had advanced inflammation (grade 3) in the acute phase; mild inflammation (grade 1) was seen in 37% of the patients at convalescence as well as in 10% of the controls. The findings in the present study suggest that in the acute phase of shigellosis inflammation is characterized by increased cell turnover in the lamina propria (LP) and the epithelium, increased iNOS expression in the surface epithelium, and apoptosis, which seems to be associated with LP macrophages. The findings also suggest that neither p53 nor iNOS are important factors for the induction of apoptosis in shigellosis. Expression of p53 may be related to early cell activation in crypt epithelium. Moreover, there is an indication of an active, low-level inflammatory process at convalescence. The results thus indicate that Shigella-induced inflammation is associated with a complex series of cellular reactions in the rectal gut mucosa which persist long after clinical symptoms have resolved.

Higher proportion of CD8+ T cells in the blood in healthy adults from Ethiopia and Bangladesh compared with Sweden.

The phenotypic composition of peripheral blood lymphocytes in 45 healthy adults (15 each from Bangladesh, Ethiopia and Sweden) was analysed as an indicator of the influence of environment and/or ethnic background on the human immune response. The possible interference of technical factors was minimized by highly standardized handling of samples and by use of a similar simultaneous 3-colour flow cytometry analysis technique for all samples. The percentage of CD4+ cells was lower, and the percentage of CD8+ cells was higher, in Bangladeshi and Ethiopian subjects than in those from Sweden. A higher percentage of CD57+/CD8+ T cells was also found in these 2 groups than in Swedish subjects. The percentage of gamma delta T cells was higher in Bangladeshi subjects and a difference in T cell receptor V beta expression was also noted between Bangladeshi and Swedish subjects. The data suggest that environmental or genetic factors are important bias factors to be considered in immunophenotyping studies. Possibly differences in the pattern or level of microbial challenge, as well as nutritional factors, may lead to different adaptive changes in the immune response. The potential influence of such immune adaptation on the response to vaccination or pharmaceutical therapy may be important in the development of new strategies of medical intervention in different geographical regions or ethnic groups.

PIP: The phenotypic composition of peripheral blood lymphocytes in 45 healthy adult blood donors (15 each from Bangladesh, Ethiopia, and Sweden) was examined as an indicator of the influence of environment and/or ethnic background on the human immune response. A highly standardized 3-color flow cytometry analysis was performed on all samples. The percentage of CD4+ cells was lower and the percentage of CD8+ cells was higher in Bangladeshi and Ethiopian subjects than in those from Sweden. A higher percentage of CD57+/CD8+ T cells was likewise found in these 2 groups compared to Swedish subjects. The percentage of gammadelta T cells was higher in Bangladeshi subjects and a difference in T cell receptor Vbeta expression was also noted between Bangladeshi and Swedish subjects. The findings suggest that environmental or genetic factors are important bias factors to be taken into account in phenotyping studies. Possible variations in the patterns or level of microbial challenge, as well as nutritional factors, may lead to different adaptive changes in the immune response. The potential influence of such immune adaptation on the response to vaccination or pharmaceutical therapy may be essential in the development of new medical intervention approaches in different geographical regions or ethnic groups.

Semiquantitative estimation of Shigella antigen-specific antibodies: correlation with disease severity during shigellosis.

Systemic and mucosal antibody responses during shigellosis were analysed and correlated with clinical severity. Patients infected with Shigella dysenteriae type 1 (SDIP), and S. flexneri (SFIP) were grouped according to disease severity. The disease was more severe in SDIP than in SFIP. Higher levels of Shigella antigen-specific serum antibodies were associated with severe disease. In contrast, decreased serum levels of IgG, IgM and total protein were associated with severe disease. Faecal levels of total IgA, secretory IgA, albumin, and LPS specific s-IgA were increased in severe disease. The results of the study indicate that the level of humoral immune response correlates with the disease severity in shigellosis and that the local immune system in the mucosa is directly engaged in the response. This is also reflected at the systemic level by increased serum levels of specific antibodies and non-specific inflammatory parameters.