Browsing by Author "S.M. Singh"

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Alteration of the immune response by tumor cells: Underlying mechanisms
(1997) S.M. Singh; Parajuli; Shrivastava; A. Sodhi
Progressive growth of a tumor is invariably accompanied by a decline in the host's immune response regardless of the location or etiology of the tumor. Moreover, the immune response in tumor-bearing host is often altered in a manner which could further promote the growth of tumor. In this review article an overview of the present state of knowledge regarding the interaction between a tumor and the host's immune system in relation to the cell types and factors involved is presented.
Alterations in the tumoricidal functions of murine tumor-associated macrophages during progressive growth of a tumor in vivo
(1997) P. Parajuli; S.M. Singh; A. Kumar; A. Sodhi
Tumor cytolytic functions of tumor-associated macrophages (TAM) obtained from different of Dalton's lymphoma (DL, a spontaneous T cell lymphoma) were studied. DL-associated macrophages (DLAM) obtained in early tumor-bearing stages showed an augmented tumor cytotoxity as well as an enhanced production of reactive nitrogen intermediates (RNI). However, these cytolytic functions declined at the later tumor-bearing stages. The effect of in vivo tumor progression on the macrophage cytolytic functions was simulated in vitro by incubating normal peritoneal macrophages (NMO) with different concentrations of DL cells. The NMO-mediated tumoricidal activity was inhibited in a DL- cell-number-dependent manner, indicating that suppressive effectors originating from DL origin acted at a higher concentration. Addition of anti- DL antiserum to these cultures reversed the DL-mediated alterations of macrophage tumoricidal functions, confirming that this suppression was mediated by the factors of DL-cell origin. The normal phenotype of DL cells (thymocytes) could not mimic the inhibitory effects of DL on macrophage functions, indicating that the macrophage-suppressive activity was a tumor- cell-restricted phenomenon. In-vivo administration of a synthetic acyl tripeptide, FK565, could increase RNI production by DLAM only at early tumor- bearing stages, while the DLAM from later tumor-bearing stages were found to be nonresponsive to this activation. These observations should be helpful in understanding the effect of in vivo growth of a T-lymphoma on the functions of tumor-associated macrophages and their responsiveness to therapeutic manipulation by a biological response modifier.
Assessment of climate change impact on different pigeonpea maturity groups in north Indian condition
(Association of Agrometeorologists, 2021) M.K. Yadav; C. Patel; R.S. Singh; K.K. Singh; R. Balasubramanian; R.K. Mall; M.K. Singh; S.M. Singh; S.K. Yadav
The CROPGRO-pigeonpea model embedded in DSSAT v4.7.5 was used to assess the impact of climate change on phenology and grain yield of reference genotype of different pigeonpea maturity groups. The impact of climate change delayed reproductive stages (anthesis, maturity) and decreased grain yield of reference genotype of different pigeonpea maturity groups were evident in all scenarios. Short duration genotypes (MN5, ICPL88039, Prabhat, UPAS120) showed progressively higher decrease in yield as compared to medium (Maruti, Asha, ICP7035) and long (Bahar, MAL13) duration genotypes with each successive increase in scenatio from RCP2.6 to RCP8.5 and projected year from 2010 to 2095. Anthesis was delayed 9 days in MN5 to 20 days in Bahar and maturity delayed 15 days in MN5 to 24 days in Bahar with RCP 8.5 in year 2095 in comparison to RCP2.6 in years 2010, whereas, grain yield was decreased 14% in Bahar to 66% in MN5 among genotypes of different maturity groups. © 2021, Association of Agrometeorologists. All rights reserved.
Assessment of climate change impact on wheat crop using MarkSim GCM in Varanasi, Uttar Pradesh
(Association of Agrometeorologists, 2018) C. Patel; A.K. Nema; R.S. Singh; M.K. Yadav; K.K. Singh; S.K. Singh; P.K. Rai; S.M. Singh
GFLD-CM3 model was used to generate weather data under RCPs scenario i.e. RCP 2.6, 4.5, 6.0 and 8.5 for years 2010, 2035, 2065 and 2095 for Varanasi, Uttar Pradesh. The generated data were used to assess the impact of climate change on phenology and yield of wheat crop using CERES-Wheat model. The results revealed that the impact climate change hastened reproductive stages (anthesis, maturity) and decreased yield in all scenarios. The impact was highest under RCP 8.5. Days to antheis and days to maturity were proj ected to reduce by 22 days and 24 days, respectively in 2095 whereas, grain yield decreased by 61.0 per cent. © 2018, Association of Agrometeorologists. All rights reserved.
Biogeography of soil bacterial populations in the Jutulsessen and Ahlmannryggen of Western Dronning Maud Land, Antarctica
(Springer Verlag, 2019) K. Staebe; K.I. Meiklejohn; S.M. Singh; G.F. Matcher
Soils of continental Antarctic nunataks represent unusual ecosystems with concomitant unique bacterial community profiles which have not been assessed for the vast majority of Antarctic nunataks. This study focussed on the previously uncharacterised inland nunataks of the Jutulsessen and Ahlmannryggen ranges in Dronning Maud Land. As with many oligotrophic soils in Antarctica, bacteria from the phyla Acidobacteria, Actinobacteria and Proteobacteria were prevalent. High relative abundances of Bacteroidetes and Chloroflexi were also observed in these soils. Potential phototrophic capabilities of these bacterial populations were indicated by the presence of genes involved in the Calvin–Benson reductive pentose phosphate cycle as well as that of aerobic phototrophic bacteriochlorophyll. Clear spatial patterns of bacterial biodiversity between nunataks in this study were observed, particularly between the Jutulsessen and Ahlmannryggen nunataks which are geographically separated by the Jutulstraumen glacier. Not unexpectedly, the bacterial community profiles found in these nunataks were distinct from those found in alternate biogeographic regions (e.g. Dry Valleys, Peninsula and Larsemann Hills). Despite belonging to the same bioregion (i.e. Dronning Maud Land), however, the clear differentiation of bacterial communities between the Jutulsessen/Ahlmannryggen and that of Sør Rondane suggests that, based on bacterial phylogeography, the Dronning Maud Land bioregion can be divided into sub-bioregions. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Characterization of factors inducing apoptosis in thymocytes of mice bearing a transplantable T-cell lymphoma of spontaneous origin
(SAP - Slovak Academic Press, spol. s.r.o., 2000) A. Shanker; S.M. Singh
It has been observed that the progressive ascitic growth of a transplantable T-cell lymphoma of spontaneous origin in murine host, designated as Dalton's lymphoma (DL), induces inhibition of various immune responses and is associated with an involution of thymus accompanied by a massive depletion of the cortical region and alteration in the distribution of thymocytes caused by induction of apoptosis with a decrease of CD4+CD8+, CD4+CD8- and CD4-CD8+ thymocytes. Here, we report that serum of DL- bearing mice contains soluble factors capable of inducing thymocyte apoptosis, the effectiveness of which increases with the progression of tumor growth. A decline of essential cytokines and hormones in the body due to their depletion by DL cells, which being a T-cell phenotype may have similar growth factor requirements, is ruled out by our results, suggesting additional apoptosis-inducing factors to be present in the tumor serum. Partial characterization of the serum to identify the biochemical nature of the putative serum-borne apoptosis inducing factor(s) showed that the same was proteinaceous. Further analysis of the sera of normal and DL-bearing mice by gel filtration using fast protein liquid chromatography (FPLC) and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that protein profile in the two sera differed quantitatively as well as qualitatively. FPLC analysis could resolve six peaks in both the sera, out of which the peak containing protein(s) in the range of MW 35 kD showed a higher magnitude and apoptotic activity followed by peaks containing proteins of MW in the range of 67 and 116 kD respectively as compared to that of the corresponding peaks in the normal serum. These observations were also confirmed by SDS-PAGE, with the resolution of additional proteins in the range of 25-26 kD which were found to be absent in normal serum. Further, the paper discusses different possible factors that could be associated with the progression of a growth.
Cyclophosphamide induced polydactyly in mice: Understanding of underlying mechanism
(2005) Prakash; Gajendra Singh; S.M. Singh
Polydactyly with 6 or 7 digits bilaterally, or in all the four limbs at a time in certain cases was the principal finding amongst limb malformations in mice fetuses exposed to cyclophosphamide in the dose of 10 mg/kg body weight on day 11 of gestation. Duplication of great toe was the most dominant. Augmentation of apoptosis by cyclophosphamide resulting in excessive programmed cell death in additional interdigital zones due to altered induction from apical ectodermal ridge (AER) with subsiquent early and fast destruction of AER and mesoderm deep to it were suggested as the probable mechanisms. Bilateral manifestation or involvement of all the four paws in multiple cases suggested, homogeneous effect of cyclophosphamide on the process of differentiation i.e. administration of critical dose at critical period of differentiation of toes.
Effect of allogeneic Dalton's lymphoma cells on the activation of murine peritoneal macrophages to tumoricidal state by cisplatin and lipopolysaccharide (LPS)
(SAP - Slovak Academic Press, spol. s.r.o., 1992) S.M. Singh; R.K. Singh; A. Sodhi
[No abstract available]
Effect of cisplatin treatment of human monocyte cell line U937 on the induction of tumoricidal activity
(SAP - Slovak Academic Press, spol. s.r.o., 1992) R.K. Singh; S.M. Singh; A. Sodhi
[No abstract available]
Effect of thymosin-alpha1 on the production of nitric oxide by tumor-associated macrophages
(SAP - Slovak Academic Press, spol. s.r.o., 2003) P. Shrivastava; S.M. Singh; N. Singh
The present investigation was conducted to study the effect of thymic peptide: thymosinα1 (thyα1) on the activation of tumor associated mφ (TAM) obtained from mice bearing a transplantable T cell lymphoma of spontaneous origin designated as Dalton's lymphoma, to produce nitric oxide (NO). It was found that in vivo administration of aqueous thymic extract obtained from thymus of normal mice or thyα1 could activate the TAM to produce enhanced amount of NO which was further augmented on in vivo treatment of these TAM by LPS. These observations suggest that thyα1 could prime TAM for activation by second signal of LPS. The study also presents evidence that tumor cell elaborate factors that enhance the effect of thyα1 on TAM for production of NO. This is the first study to show that thyα1 can activate TAM directly even in the absence of LPS, and may, therefore, have clinical significance.
Effect of TNFα on the induction of apoptosis in murine macrophage: Role of interleukin-1β converting enzime
(Biomedical Research Press s.a.s., 2001) A. Acharya; S.M. Singh
Tumor necrosis factor α (TNF α) is a cytokine that induces apoptosis in various cell types via its binding to TNF-receptors (TNF-R). Involvement of ICE-like protease in the induction of TNF-α mediated apoptosis in murine macrophage was investigated using ICE inhibitor YVAD-cmk (Tetrapeptide-Acetyl-Try-Val-Ala-Asp-Chloromethyl ketone). Macrophages treated with TNF showed a time dependent decrease in cell viability with a simultaneous increase in the % of cells showing apoptotic morphology and an increase in % DNA fragmentation, a quantitative measure of apoptosis. However, incubation of macrophage in medium containing TNF and YVAD-cmk had inhibitory effect on the TNF-induced apoptosis of macrophage. This finding suggests that ICE-like protease may be involved in the induction of apoptosis in macrophage by TNF-α.
Effect of tumor cells on the activation of murine lymphocytes and macrophages by cisplatin and FK565
(SAP - Slovak Academic Press, spol. s.r.o., 1997) A. Kumar; S.M. Singh; A. Sodhi
Murine peritoneal macrophages on in vitro treatment with cisplatin (55 μg/ml or FK565 (10 μg/ml) showed an enhanced production of tumor necrosis factor (TNF) and reactive nitrogen intermediates (RNI). Similarly, treatment of splenic lymphocytes with these agents also led to an enhanced production of TNF. Co-incubation of macrophages or splenic lymphocytes with P815 (a murine mastocytoma) cells in vitro in the absence of cisplatin or FK565 also resulted in an augmented TNF production, however, it had no effect on the RNI production by macrophages. TNF production of cisplatin-or FK565-treated macrophages got synergistically enhanced in the presence of P815 cells whereas the production of RNI was inhibited. Incubation of splenic lymphocytes with P815 cells in the presence of cisplatin or FK565 resulted in an inhibition of TNF production. Indomethacin-treated P815 cells were observed to be less effective in inhibiting nitrite production of macrophages compared to untreated tumor cells. Pretreatment of P815 cells with cisplatin or FK565 before co-incubation did not alter the TNF production of macrophages whereas it inhibited the same in lymphocytes. This study shows that activation of macrophages and lymphocytes is independently influenced by P815 tumor cells in combination with chemoimmunotherapeutic drugs cisplatin and FK565.
First case of cryptococcosis in a new species of bandicoot (Bandicota indica) caused by Cryptococcus neoformans var. grubii
(2007) S.M. Singh; J. Naidu; A. Sharma; S.R. Nawange; K. Singh
The first case of cryptococcosis caused by Cryptococcus neoformans var. grubii in a new species of bandicoot (Bandicota indica) is described. The animal was trapped in a bamboo thicket in a park located in the city of Jabalpur, India. On necropsy, pathological lesions were seen in the lungs and liver and C. neoformans var. grubii was isolated from the lungs, liver, kidneys, spleen and brain but not the heart or intestine. The soil of the animal's burrow and bamboo debris around it also revealed the presence of C. neoformans var. grubii. We hypothesize that the bandicoots may potentially act as sentinel animals for environmental human pathogenic Cryptococcus species.
Fungal planet description sheets: 868-950
(Nationaal Herbarium Nederland, 2019) P.W. Crous; A.J. Carnegie; M.J. Wingfield; R. Sharma; G. Mughini; M.E. Noordeloos; A. Santini; Y.S. Shouche; J.D.P. Bezerra; B. Dima; V. Guarnaccia; I. Imrefi; Ž. Jurjević; D.G. Knapp; G.M. Kovács; D. Magistà; G. Perrone; T. Rämä; Y.A. Rebriev; R.G. Shivas; S.M. Singh; C.M. Souza-Motta; R. Thangavel; N.N. Adhapure; A.V. Alexandrova; A.C. Alfenas; R.F. Alfenas; P. Alvarado; A.L. Alves; D.A. Andrade; J.P. Andrade; R.N. Barbosa; A. Barili; C.W. Barnes; I.G. Baseia; J.-M. Bellanger; C. Berlanas; A.E. Bessette; A.R. Bessette; A.Yu. Biketova; F.S. Bomfim; T.E. Brandrud; K. Bransgrove; A.C.Q. Brito; J.F. Cano-Lira; T. Cantillo; A.D. Cavalcanti; R. Cheewangkoon; R.S. Chikowski; C. Conforto; T.R.L. Cordeiro; J.D. Craine; R. Cruz; U. Damm; R.J.V. De Oliveira; J.T. De Souza; H.G. De Souza; J.D.W. Dearnaley; R.A. Dimitrov; F. Dovana; A. Erhard; F. Esteve-Raventós; C.R. Félix; G. Ferisin; R.A. Fernandes; R.J. Ferreira; L.O. Ferro; C.N. Figueiredo; J.L. Frank; K.T.L.S. Freire; D. García; J. Gené; A. Gęsiorska; T.B. Gibertoni; R.A.G. Gondra; D.E. Gouliamova; D. Gramaje; F. Guard; L.F.P. Gusmão; S. Haitook; Y. Hirooka; J. Houbraken; V. Hubka; A. Inamdar; T. Iturriaga; I. Iturrieta-González; M. Jadan; N. Jiang; A. Justo; A.V. Kachalkin; V.I. Kapitonov; M. Karadelev; J. Karakehian; T. Kasuya; I. Kautmanová; J. Kruse; I. Kušan; T.A. Kuznetsova; M.F. Landell; K.-H. Larsson; H.B. Lee; D.X. Lima; C.R.S. Lira; A.R. Machado; H. Madrid; O.M.C. Magalhães; H. Majerova; E.F. Malysheva; R.R. Mapperson; P.A.S. Marbach; M.P. Martín; A. Martín-Sanz; N. Matočec; A.R. McTaggart; J.F. Mello; R.F.R. Melo; A. Mešić; S.J. Michereff; A.N. Miller; A. Minoshima; L. Molinero-Ruiz; O.V. Morozova; D. Mosoh; M. Nabe; R. Naik; K. Nara; S.S. Nascimento; R.P. Neves; I. Olariaga; R.L. Oliveira; T.G.L. Oliveira; T. Ono; M.E. Ordoñez; A.M. Ottoni; L.M. Paiva; F. Pancorbo; B. Pant; J. Pawłowska; S.W. Peterson; D.B. Raudabaugh; E. Rodríguez-Andrade; E. Rubio; K. Rusevska; A.L.C.M.A. Santiago; A.C.S. Santos; C. Santos; N.A. Sazanova; S. Shah; J. Sharma; B.D.B. Silva; J.L. Siquier; M.S. Sonawane; A.M. Stchigel; T. Svetasheva; N. Tamakeaw; M.T. Telleria; P.V. Tiago; C.M. Tian; Z. Tkalčec; M.A. Tomashevskaya; H.H. Truong; M.V. Vecherskii; C.M. Visagie; A. Vizzini; N. Yilmaz; I.V. Zmitrovich; E.A. Zvyagina; T. Boekhout; T. Kehlet; T. Læssøe; J.Z. Groenewald
Novel species of fungi described in this study include those from various countries as follows: Australia, Chaetomella pseudocircinoseta and Coniella pseudodiospyri on Eucalyptus microcorys leaves, Cladophialophora eucalypti, Teratosphaeria dunnii and Vermiculariopsiella dunnii on Eucalyptus dunnii leaves, Cylindrium grande and Hypsotheca eucalyptorum on Eucalyptus grandis leaves, Elsinoe salignae on Eucalyptus saligna leaves, Marasmius lebeliae on litter of regenerating subtropical rainforest, Phialoseptomonium eucalypti (incl. Phialoseptomonium gen. nov.) on Eucalyptus grandis camaldulensis leaves, Phlogicylindrium pawpawense on Eucalyptus tereticornis leaves, Phyllosticta longicauda as an endophyte from healthy Eustrephus latifolius leaves, Pseudosydowia eucalyptorum on Eucalyptus sp. leaves, Saitozyma wallum on Banksia aemula leaves, Teratosphaeria henryi on Corymbia henryi leaves. Brazil, Aspergillus bezerrae, Backusella azygospora, Mariannaea terricola and Talaromyces pernambucoensis from soil, Calonectria matogrossensis on Eucalyptus urophylla leaves, Calvatia brasiliensis on soil, Carcinomyces nordestinensis on Bromelia antiacantha leaves, Dendryphiella stromaticola on small branches of an unidentified plant, Nigrospora brasiliensis on Nopalea cochenillifera leaves, Penicillium alagoense as a leaf endophyte on a Miconia sp., Podosordaria nigrobrunnea on dung, Spegazzinia bromeliacearum as a leaf endophyte on Tilandsia catimbauensis, Xylobolus brasiliensis on decaying wood. Bulgaria, Kazachstania molopis from the gut of the beetle Molops piceus. Croatia, Mollisia endocrystallina from a fallen decorticated Picea abies tree trunk. Ecuador, Hygrocybe rodomaculata on soil. Hungary, Alfoldia vorosii (incl. Alfoldia gen. nov.) from Juniperus communis roots, Kiskunsagia ubrizsyi (incl. Kiskunsagia gen. nov.) from Fumana procumbens roots. India, Aureobasidium tremulum as laboratory contaminant, Leucosporidium himalayensis and Naganishia indica from windblown dust on glaciers. Italy, Neodevriesia cycadicola on Cycas sp. leaves, Pseudocercospora pseudomyrticola on Myrtus communis leaves, Ramularia pistaciae on Pistacia lentiscus leaves, Neognomoniopsis quercina (incl. Neognomoniopsis gen. nov.) on Quercus ilex leaves. Japan, Diaporthe fructicola on Passiflora edulis P. edulis f. flavicarpa fruit, Entoloma nipponicum on leaf litter in a mixed Cryptomeria japonica and Acer spp. forest. Macedonia, Astraeus macedonicus on soil. Malaysia, Fusicladium eucalyptigenum on Eucalyptus sp. twigs, Neoacrodontiella eucalypti (incl. Neoacrodontiella gen. nov.) on Eucalyptus urophylla leaves. Mozambique, Meliola gorongosensis on dead Philenoptera violacea leaflets. Nepal, Coniochaeta dendrobiicola from Dendriobium lognicornu roots. New Zealand, Neodevriesia sexualis and Thozetella neonivea on Archontophoenix cunninghamiana leaves. Norway, Calophoma sandfjordenica from a piece of board on a rocky shoreline, Clavaria parvispora on soil, Didymella finnmarkica from a piece of Pinus sylvestris driftwood. Poland, Sugiyamaella trypani from soil. Portugal, Colletotrichum feijoicola from Acca sellowiana. Russia, Crepidotus tobolensis on Populus tremula debris, Entoloma ekaterinae, Entoloma erhardii and Suillus gastroflavus on soil, Nakazawaea ambrosiae from the galleries of Ips typographus under the bark of Picea abies. Slovenia, Pluteus ludwigii on twigs of broadleaved trees. South Africa, Anungitiomyces stellenboschiensis (incl. Anungitiomyces gen. nov.) and Niesslia stellenboschiana on Eucalyptus sp. leaves, Beltraniella pseudoportoricensis on Podocarpus falcatus leaf litter, Corynespora encephalarti on Encephalartos sp. leaves, Cytospora pavettae on Pavetta revoluta leaves, Helminthosporium erythrinicola on Erythrina humeana leaves, Helminthosporium syzygii on a Syzygium sp. bark canker, Libertasomyces aloeticus on Aloe sp. leaves, Penicillium lunae from Musa sp. fruit, Phyllosticta lauridiae on Lauridia tetragona leaves, Pseudotruncatella bolusanthi (incl. Pseudotruncatellaceae fam. nov.) and Dactylella bolusanthi on Bolusanthus speciosus leaves. Spain, Apenidiella foetida on submerged plant debris, Inocybe grammatoides on Quercus ilex subsp. ilex forest humus, Ossicaulis salomii on soil, Phialemonium guarroi from soil. Thailand, Pantospora chromolaenae on Chromolaena odorata leaves. Ukraine, Cadophora helianthi from Helianthus annuus stems. USA, Boletus pseudopinophilus on soil under slash pine, Botryotrichum foricae, Penicillium americanum and Penicillium minnesotense from air. Vietnam, Lycoperdon vietnamense on soil. Morphological and culture characteristics are supported by DNA barcodes. © 2019 Naturalis Biodiversity Center & Westerdijk Fungal Biodiversity Institute.
Histological changes in ovaries of mice exposed to Butea monosperma: Preliminary study; [cambios histológicos en ovarios de ratón expuestos a Butea monosperma: Estudio preliminar]
(Universidad de la Frontera, 2010) Neelam Gupta; Gajendra Singh; S.M. Singh; K.R.C. Reddy
In Ayurvedic practice Butea onosperma (Palash) is in clinical use for hundreds of years as a ontraceptive. Seeds of Butea monosperma are also used as an anthelmitic (Ansani et al., 1979) and antimicrobial (Avirutnant & Pongpan, 1983). Butea monosperma (Fabaceae family) locally known as Palash (Dhak) if given for 3 consecutive days acts as an antifertility agent for which it has been is traditionally used since time immemorial. The objective of the present study was to search the effect of Butea monosperma seeds on the ovary of mice. Observations in the present study were massive degeneration of ova in almost all the follicles, irrespective of the stage of their development. The ova from treated animals showed different stages of necrotic process. Moreover, the arrangement of follicular cells was also disturbed. The Palash seeds in the form of powder when administered orally with distilled water, according to the body weight i.e.2g/Kg, of female mice, for three consecutive days showed notable changes in ovaries. The animals were sacrificed on day next to the last day of treatment and ovaries were extirpated. varies studied histologically after Haematoxylin & Eosin staining showed most of the follicle in immature state with ndefined nucleus and nucleoli in the ovum. Others showed degenerative changes in the ovum. Follicles had lost their normal shape and arrangement and organization of granulosa cells. It was conspicuous to find that almost all follicles including graafian follicles of treated ovaries were undergoing degenerative changes simultaneously. The rate of apoptosis in the granulosa cells when studied was found increased in treated cases as compared with control. The study suggests that the disintegration of ova in the ovaries is a specific effect of Butea monosperma seed administration.
Immunopotentiation in mice bearing a spontaneous transplantable T-cell lymphoma: Role of thymic extract
(SAP - Slovak Academic Press, spol. s.r.o., 2003) A. Shanker; S.M. Singh
Progressive ascitic growth of a spontaneous transplantable T-cell lymphoma, designated as Dalton's lymphoma (DL), in a murine host has been shown to be associated with an involution of thymus accompanied by a massive depletion of the cortical region and an alteration in the distribution of thymocytes by a decrease of CD4+ CD8+, CD4+CD8- and CD4-CD8+ phenotypes caused by an enhanced induction of apoptosis in thymocytes. Moreover, an inhibition of humoral and cell mediated immune responses involving non-specific as well as antigen-specific T cell proliferative and cytolytic abilities with a decrease in the production of interferon γ (IFNγ) by the T cells of DL bearing mice has been observed. Results of the present study show that the administration of total thymic extract (TE) in DL bearing mice results in an increased survival of the DL bearing mice alongwith a significant increase in the weight of thymus and the total number of thymocytes with a lesser number of percent apoptotic thymocytes as compared to that in untreated DL-bearing mice. It is also shown that TE administration has a positive immunomodulatory effect on T cell functions as T cells obtained from TE administered DL-bearing mice show an increased IFNγ, production and an improved antigen specific proliferative ability. Moreover, the study indicates that TE acts directly on T cells as in an in vitro assay TE antagonised DL growth-associated induction of thymocyte apoptosis. Taken together, the results support the immunomodulatory function of the adult thymus and utilization of thymus derived factors as a potential immunotherapeutic agent for reversing tumor growth-associated immunosuppression.
Morpho-histology of head kidney of female catfish Heteropneustes fossilis: seasonal variations in melano-macrophage centers, melanin contents and effects of lipopolysaccharide and dexamethasone on melanins
(Springer Netherlands, 2016) Ravi Kumar; K.P. Joy; S.M. Singh
In the catfish Heteropneustes fossilis, the anterior kidney is a hemopoietic tissue which surrounds the adrenal homologues, interrenal (IR) and chromaffin tissues corresponding to the adrenal cortical and adrenal medulla of higher mammals. The IR tissue is arranged in cell cords around the posterior cardinal vein (PCV) and its tributaries and secretes corticosteroids. The chromaffin tissue is scattered singly or in nests of one or more cells around the epithelial lining of the PCV or blood capillaries within the IR tissue. They are ferric ferricyanide-positive. Leukemia-inhibitory factor (LIF)-like reactivity was noticed in the lining of the epithelium of the IR cell cords and around the wall of the PCV and blood capillaries. No staining was observed in the hemopoietic cells. IL-1β- and TNF-α-like immunoreactivity was seen in certain cells in the hemopoietic tissue but not in the IR region. Macrophages were identified with mammalian macrophage-specific MAC387 antibodies and are present in the hemopoietic mass but not in the IR tissue. Pigments accumulate in the hemopoietic mass as melano-macrophage centers (MMCs) and are PAS-, Schmorl’s- and Perls’-positive. The pigments contain melanin (black), hemosiderin (blue) and lipofuscin/ceroid (oxidized lipid, yellowish tan), as evident from the Perls’ reaction. The MMCs were TUNEL-positive as evident from FITC fluorescence, indicating their apoptotic nature. The MMCs showed significant seasonal variation with their density increasing to the peak in the postspawning phase. Melanins were characterized spectrophotometrically for the first time in fish anterior kidney. The predominant form is pheomelanin (PM), followed by eumelanin (EM) and alkali-soluble melanin (ASM). Melanins showed significant seasonal variations with the level low in the resting phase and increasing to the peak in the postspawning phase. Under in vitro conditions, lipopolysaccharide (10 µg/mL) treatment increased significantly the levels of PM and EM levels both at 16 and at 32 h and the ASM level at 32 h. On the other hand, the synthetic glucocorticoid dexamethasone (100 nM) decreased significantly the levels of EM, PM and ASM time-dependently. The results indicate that the anterior kidney is an important site of immune–endocrine interaction. © 2016, Springer Science+Business Media Dordrecht.
Naturally acquired systemic dual infection caused by Candida famata (Debaryomyces hansenii) and Candida catenulata in albino rats bred for sale in the market at Jabalpur (Madhya Pradesh), India
(2010) Shesh R. Nawange; K. Singh; J. Naidu; S.M. Singh
Naturally acquired disseminated dual infection caused by Candida famata and Candida catenulata was observed in a group of albino rats bred in an animal house for sale at Jabalpur, India. Out of 200 rats examined, 40 (20%) revealed disseminated infection from which 10 (5%) exhibited infection of the brain. Mixed colonies of C. famata and C. catenulata were isolated in culture from brain, heart, lungs, liver, kidneys, spleen and stomach of the diseased animals. Histopathology revealed the presence of necrotic lesions containing yeast cells. Epidemiological studies showed the presence of the pathogens in the soil of the animal's breeding place. It is suggested that the rats may have acquired infection from the soil either through contaminated food, drinking water or aerosol. This is the first report of the naturally acquired dual infection in albino rats caused by C. famata (Debaryomyces hansenii) and C. catenulata. © 2009 Blackwell Verlag GmbH.
Reply to Prof. Randhawa [1]
(2007) S.M. Singh; J. Naidu; A. Sharma; S.R. Nawange; K. Singh
[No abstract available]
Some thoughts on the mechanism of acetal formation and related reactions: Extension of Baldwin's rules for ring closure
(1981) O.P. Reddy; S.M. Singh; R.Balaji Rao
Extension of Baldwin's rules for ring closure to dioxolane formation and related reactions has been attempted. A plausible mechanism has been arrived at on the basis of available literature evidence and earlier work reported from our laboratory. © 1981.