Effect of functional groups on antioxidant properties of substituted selenoethers

Selenoethers attached to functional groups through propyl chain viz., bis(3-carboxypropyl)selenide (SeBA), bis(3-hydroxypropyl)selenide (SePOH) and bis(3-aminopropyl)selenide dihydrochloride (SePAm), have been examined for their ability to inhibit peroxyl radical mediated DNA damage, peroxyl radical scavenging ability and glutathione peroxidase (GPx) like activity. The DNA damage was monitored by gel electrophoresis, bimolecular rate constants for scavenging of model peroxyl radical were determined by pulse radiolysis and the GPx activity was followed by their ability to reduce hydrogen peroxide in the presence of glutathione utilizing NADPH decay and HPLC analysis. Among these compounds, SeBA showed maximum DNA protecting activity and it was also the most efficient in scavenging peroxyl radicals with the highest GPx mimicking activity. Quantum chemical calculations confirmed that SeBA with the highest energy level of HOMO (highest occupied molecular orbital) is the easiest to undergo oxidation and therefore exhibits better radical scavenging, GPx mimicking and DNA protecting activity than SePOH or SePAm.

In vivo radioprotection studies of 3,3'-diselenodipropionic acid, a selenocystine derivative

3,3'-Diselenodipropionic acid (DSePA), a diselenide and a derivative of selenocystine, was evaluated for in vivo radioprotective effects in Swiss albino mice, at an intraperitoneal dose of 2 mg/kg body wt, for 5 days before whole-body exposure to gamma-radiation. The radioprotective efficacy was evaluated by assessing protection of the hepatic tissue, the spleen, and the gastrointestinal (GI) tract and survival against sub- and supralethal doses of gamma-radiation. DSePA inhibited radiation-induced hepatic lipid peroxidation, protein carbonylation, loss of hepatic function, and damage to the hepatic architecture. DSePA also attenuated the depletion of endogenous antioxidants such as glutathione, glutathione peroxidase, superoxide dismutase, and catalase in the livers of irradiated mice. DSePA also restored the radiation-induced reduction in villus height, crypt cell numbers, and spleen cellularity, indicating protective effects on the GI tract and the hematopoietic system. The results from single-cell gel electrophoresis of the peripheral blood leukocytes showed that DSePA can attenuate radiation-induced DNA damage. The mRNA expression analysis of genes revealed that DSePA augmented GADD45alpha and inhibited p21 in both spleen and liver tissues. DSePA also inhibited radiation-induced apoptosis in the spleen and reversed radiation-induced alterations in the expression of the proapoptotic BAX and the antiapoptotic Bcl-2 genes. In line with these observations, DSePA improved the 30-day survival of irradiated mice by 35.3%. In conclusion, these findings clearly confirm that DSePA exhibits protective effects against whole-body gamma-radiation and the probable mechanisms of action involve the maintenance of antioxidant enzymes, prophylactic action through the attenuation of the DNA damage, and inhibition of apoptosis.

In vitro radioprotection studies of organoselenium compounds: differences between mono- and diselenides

Organoselenium compounds belonging to the class of monoselenides, such as selenomethionine (SeM) and methylselenocysteine (MSeCys) and diselenides including selenocystine (SeCys) and selenopropionic acid (SePA), were examined for their comparative radioprotective effects using in vitro models. Effects of these compounds on the inhibition of gamma-radiation induced lipid peroxidation in liposomes, protein carbonylation in bovine serum albumin (BSA) and strand breaks in pBR322 plasmid DNA, assessed, respectively, by the formation of thiobarbituric acid reactive substances, formation of 2,2'-dinitrophenyl hydrazine (DNPH) carbonyl complex and horizontal gel electrophoresis, were used to compare their radioprotective ability. The IC 50 values for SeCys, SePA, SeM and MSeCys for lipid peroxidation were 27 +/- 1, 33 +/- 2, 200 +/- 8 and 163 +/- 4 microM, respectively, and the values for inhibition of protein carbonylation were >200, 300 +/- 6, 464 +/- 8 and 436 +/- 3 microM, respectively. Inhibition of DNA strand break formation was tested at 200 microM for all the compounds and SePA and SeCys exhibited a protective effect on DNA, while SeM and MSeCys did not lead to any protection. The in vitro cytotoxicity studies in normal and tumor cells revealed that MSeCys and SeM were not cytotoxic to lymphocytes and EL4 tumor cells at the concentrations employed. In contrast, SeCys was toxic, with a higher effect on tumor cells than lymphocytes. Our studies suggest that the non-toxic diselenides like SePA should be explored as protective agents against gamma-irradiation induced damage.

SEM-EDX analysis of various sizes aerosols in Delhi India

Scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) was used to understand the differences in morphology, elemental composition and particle density of aerosols in different five size ranges to further investigate the potential sources as well as transport of pollutants from/at a much polluted and a very clean area of Delhi. Aerosol samples were obtained in five different size ranges viz. > or = 10.9, 10.9-5.4, 5.4-1.6, 1.6-0.7 and < or = 0.7 microm from a considerably very clean and a much polluted area of Delhi. It was observed that at polluted area most of the particles irrespective of size are of anthropogenic origin. At clean area, in coarse size fractions particles are of natural origin while in fine size range the presence of anthropogenic particles suggests the transport of particles from one area to the other.

Atmospheric polycyclic aromatic hydrocarbons (PAHs) in the urban air of Delhi during 2003

Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) in Delhi were evaluated to study particulate PAHs profiles during the different seasons of 2003. Samples of urban suspended particulate matter were collected during January 2003 to December 2003 at three locations (Okhla, Dhaulakuan and Daryaganj), using a high volume sampler provided with glass fiber filters. Samples were analyzed using the gas chromatography technique. The annual average concentrations of total PAHs were found as 1,049.3 ng/m(3) at Okhla, 1,344.37 ng/m(3) at Daryaganj, and 1,117.14 ng/m(3) at Dhaulakuan. The seasonal average concentrations were found to be maximum in winter and minimum during the monsoon season. Principal Component Analysis (PCA) of the data was also carried out and the results indicate that diesel and gasoline driven vehicles are the principal sources of PAHs at all the three sites under investigation. Other sources might come from stationary combustion sources such as cooking fuel combustion and industrial emission.

A clinically relevant major cross-reactive allergen from mesquite tree pollen

BACKGROUND

Prosopis juliflora (mesquite) is one of the major sources of pollinosis in tropical and semi-arid countries of the world. The present study was undertaken to purify and characterize a major cross-reactive allergen from this tree species.

MATERIALS AND METHODS

Mesquite pollen extract was purified using reverse-phase chromatography. Allergen characterization was done by electrophoresis, enzyme-linked immunosorbent assay (ELISA) and Western blotting. Clinical relevance of the purified protein was analyzed by in vivo (skin tests) and in vitro experiments such as ELISA, histamine release, peripheral blood mononuclear cells (PBMC) proliferation and cytokine assays. Cross-reactivity of purified protein with allergenic tree species and lima bean (food) was assessed by inhibition assays.

RESULTS

A 66-kDa protein was purified from mesquite pollen extract using octadecyl silica resin. Purified protein recognized 90% of mesquite-sensitized patients in skin test and ELISA. It induced significant histamine release in allergic patients' blood and interleukin-4 secretion in the PBMC culture supernatants. Inhibition assays suggested close allergenic relationship of this protein with Ailanthus excelsa, Cassia siamea, Salvadora persica pollen and Phaseolus lunatus (lima bean - an edible legume).

CONCLUSIONS

A 66-kDa major cross-reactive allergen was isolated from mesquite pollen using single-step purification procedure. The protein seems relevant for clinical applications in allergic disorders.

Late onset isotretinoin resistant acne conglobata in a patient with acromegaly

A 55 year-old male presented with multiple pus-discharging abscesses and sinuses and mutilating scarring on the gluteal region and back prevalent for the last ten years with exacerbations and remissions. Physical examination revealed acromegaly with frontal bossing, prognathism, a barrel chest and acral hypertrophy. Dermatological examination revealed cutis verticis gyrata, thick eyelids, a large triangular nose, a thickened lower lip, macroglossia, widely spaced teeth and widened skin pores with wet and oily skin. Hair was fine and nails were flat and wide. There were multiple inflammatory papules, tender nodules, draining sinuses, and grouped, polyporous comedones as well as multiple and extensive depressed and keloidal scars localized predominantly over the gluteal region with a few scattered lesions over the back. A computed tomography (CT) scan showed widened sella turcica. His basal fasting growth hormone (GH) levels were markedly raised (230 ng/mL; normal 1-5 ng/mL) while the prolactin levels were moderately raised (87 ng/mL; normal 2-5 ng/mL). These findings were consistent with a diagnosis of acromegaly. The patient was put on antibiotics, nonsteroidal antiinflammatory drugs and isotretinoin at a dose of 1 mg/kg/day, which was increased to 1.5 mg/kg/day. Except for an initial mildly beneficial response, the skin lesions were largely resistant to high doses of isotretinoin at the end of four months.

Particle size distribution of aerosols and associated heavy metals in kitchen environments

Mass size distributions of total suspended particulate matter (TSPM) was measured from Sep 2002 to April 2003 in indoor kitchen environments of five locations in Jawaharlal Nehru University (JNU), New Delhi, with the help of a high volume cascade impactor. Particulate matters were separated in five different size ranges, i.e. >10.9 microm, 10.9-5.4 microm, 5.4-1.6 microm, 1.6-0.7 microm and <0.7 microm. The particle size distribution at various sites appears to follow uni-modal trend corresponding to fine particles i.e. size range <0.7 microm. The contributions of fine particles are estimated to be approximately 50% of TSPM and PM10.9, while PM10.9 comprises 80% of TSPM. Good correlations were observed between various size fractions. Regression results reveal that TSPM can adequately act as a surrogate for PM10.9 and fine particles, while PM10.9 can also act as surrogate for fine particles. The concentrations of heavy metals are found to be dominantly associated with fine particles. However, the concentration of some metals and their size distribution, to some extent is also site specific (fuel type used).

Identification of polycyclic aromatic hydrocarbons (PAHs) in suspended particulate matter by synchronous fluorescence spectroscopic technique

The synchronous fluorescence (SF) technique has been used in the identification of polycyclic aromatic hydrocarbons (PAHs) from air particulate sample in an urban environment of Delhi, Jawaharlal Nehru University. Suspended particulate matter samples of 24h duration were collected on glass fiber filter papers. PAHs were extracted from the filter papers using dichloromethane (DCM)+hexane with ultrasonication method. Qualitative measurements of the polycyclic aromatic hydrocarbons (PAHs) were carried out using the SF technique at various wavelength intervals (Deltalambda). Due to the difference in chemical structure, each PAH gives specific characteristic spectrum for each Deltalambda. Following PAHs were detected in our measurement: benz(a)anthracene (BaA), pyrene (Pyr), chrysene (Chry), fluoranthene (Flan), phenanthrene (Phen), and benz(ghi)perylene (BghiP). This is in agreement with our earlier work for determination of these PAHs using gas chromatography (GC). The seasonal variation of the PAHs was found to be maximum in winter and minimum during the monsoon.

An estimation of annoyance due to various public modes of transport in Delhi

Measurements of noise levels associated with different types of vehicles plying the roads in Delhi were made. From the data, noise level indices L(10) , L(90) and Leq were determined. In addition, spectra of noise for different vehicles at 1- octave band frequencies were also obtained. The time-averaged noise spectra reveal that the noise intensities are significantly higher in the frequency range of 0.5 kHz to 2 kHz for all types of vehicles. Perceived noise levels (PNdB) and the total noisiness measured on NOY scale indicate that rural transport vehicles (RTVs) are most annoying, followed by buses, auto-rickshaws and taxis.

Management strategies for bilateral vestibular schwannomas

BACKGROUND

Bilateral vestibular schwannomas (VS) are rare. Most patients in India present late in the course of illness with large tumors and disabling deafness. Clinical presentation and management goals are different from that of unilateral VS.

AIMS

To highlight the differences in clinical presentations and surgical results of bilateral VS compared to unilateral VS; and, to propose a management strategy for these tumors with reference to tumor size, extent of growth and the presence or absence of hearing impairment.

METHOD

This is a retrospective study of 16 patients with bilateral VS treated over 10 years in a tertiary referral hospital. Assessment of VIIth and VIIIth cranial nerve function, tumor size, volume and extent of growth was performed in all patients. The management strategy was based on Samii's classification of tumor extent. All patients were operated using a retromastoid suboccipital approach. Postoperative results were analyzed and compared with those of unilateral VS.

RESULTS

The mean age of presentation was 25.7 years. Hearing impairment was the commonest symptom. Headache with features of raised intracranial pressure were present in 10 (62.5%) patients. Giant tumors were present in seven (43.7%) patients; large tumors in eight (50%) and a medium-sized tumor in one (6.3%). Total tumor resection was achieved in 13 patients and subtotal resection in two. One patient was managed conservatively and followed up with serial CT scans. On the contralateral side, one large tumor required total excision. One medium sized tumor underwent sub-capsular excision in an attempt to preserve hearing. The facial nerve was anatomically preserved in seven (46.7%) patients and in one, the cochlear nerve was anatomically preserved. There was no peri-operative mortality.

CONCLUSIONS

Patients with bilateral schwannomas are younger, have larger lesions, poorer preoperative hearing and are more likely to lose either auditory and/or facial nerve function during attempted total resection of the tumor. Classifying the tumors into two groups by extent, that is, tumors extending to the cerebellopontine angle cistern (T1-T3a) and, tumors extending to or compressing the brainstem (T3b to T4b), allows the surgical strategy to be defined.

Immunoglobulin E (IgE)-mediated cross-reactivity between mesquite pollen proteins and lima bean, an edible legume

Immunoglobulin E (IgE)-mediated food allergy often develops as a consequence of allergic sensitization to pollen proteins. Mesquite (Prosopis juliflora) tree pollen is reported to be cross-reactive with other pollen species, but little has been reported on its cross-reactivity with plant-derived foods belonging to the same/different families. The present study investigates the in vitro cross-reactivity of mesquite pollen and lima bean (Phaseolus lunatus), an edible seed belonging to the Leguminosae family. Of 110 patients (asthma, rhinitis or both) tested intradermally, 20 showed marked positive reactions with Prosopis pollen extract. Of these, 12 patients showed elevated specific IgE to Prosopis pollen extract alone and four to both Phaseolus and pollen extract. In vitro cross-reactivity was investigated using inhibition assays [enzyme-linked immunosorbent assay (ELISA) inhibition, immunoblot inhibition], histamine release and lymphoproliferation. P. lunatus extract could inhibit IgE binding to P. juliflora in a dose-dependent manner, requiring 400 ng of protein for 50% inhibition in ELISA assay. Immunoblot and immunoblot inhibition demonstrated the presence of 20, 26, 35, 66 and 72 kDa as shared IgE binding components between the two extracts. Histamine release, peripheral blood mononuclear cells proliferation and interleukin (IL)-4 levels also suggested allergenic cross-reactivity. In conclusion, there is humoral and cellular cross-reactivity between Prosopis pollen and Phaseolus seed allergens.