66 research outputs found
Representation of Minorities in Research: A View from the Community
No full textAUTHOR AFFILIATION: Sudarshan Pyakurel, Arogya Institute and Bhutanese Nepali Community of Central Ohio, United States, [email protected] media can be accessed here:
http://streaming.osu.edu/knowledgebank/PREA/PREA_Session13C_Pyakurel_20190326.mp
Extracellular Regulated Kinase Phosphorylates Mitofusin 1 to Control Mitochondrial Morphology and Apoptosis.
No full textTrichoplein/mitostatin regulates endoplasmic reticulum-mitochondria juxtaposition.
No full textTrichoplein/mitostatin (TpMs) is a keratin-binding protein that partly colocalizes with mitochondria and is often downregulated in epithelial cancers, but its function remains unclear. In this study, we report that TpMs regulates the tethering between mitochondria and endoplasmic reticulum (ER) in a Mitofusin 2 (Mfn2)-dependent manner. Subcellular fractionation and immunostaining show that TpMs is present at the interface between mitochondria and ER. The expression of TpMs leads to mitochondrial fragmentation and loosens tethering with ER, whereas its silencing has opposite effects. Functionally, the reduced tethering by TpMs inhibits apoptosis by Ca(2+)-dependent stimuli that require ER-mitochondria juxtaposition. Biochemical and genetic evidence support a model in which TpMs requires Mfn2 to modulate mitochondrial shape and tethering. Thus, TpMs is a new regulator of mitochondria-ER juxtaposition
AIDS and endemic Kaposi's sarcoma development : comparison by histopathology, virology (HHV8/KSHV) and cytogenetics
No full textKaposi’s sarcoma (KS) is a highly and abnormally vascularized tumor-like lesion with spindle cells (SC) affecting the skin, lymphnodes and viscera which is found in four different clinico-epidemiological forms as Classic KS (CKS), Iatrogenic KS (IKS), Endemic KS (EKS) and AIDS-associated KS (AKS). All KS forms develop from early stages of patch/plaque to late, nodular tumors and are associated with Kaposi's sarcomaassociated herpesvirus or human herpesvirus-8 (KSHV/ HHV-8). HHV-8 is also associated with primary effusion lymphoma (PEL) and multicentric castleman's disease (MCD). Various studies favour an endothelial origin (CD34+) of the KS SC but whether of vascular (VEC) or lymphatic endothelial cell (LEC) origin has not been settled. The HHV-8 latency-associated nuclear antigen type 1 (LANA-1) protein is the most frequently expressed viral antigen in infected cells. KS is promoted by HIV infection mainly by the angiogenic and proinflammatory effects of HIV-Tat. Whether KS represents a predominantly monoclonal neoplastic cell proliferation or a hyperplastic, reactive polyclonal process is still controversial. Reports on cytogenetic and molecular genetic changes in KS are few indicating that initially KS may develop as a reactive polyclonal cell proliferation associated with chromosome instability, followed by clonal chromosome changes in later stages.In the present KS histopathological studies (paper I & V) by triple antibody immunofluorescence we observed that: (a) the frequency of LANA+/CD34+ cells increased from early patch to late KS nodular lesions; (b) 30- 40% of the CD34+ SC were LANA- in both early and late KS, suggesting a continuous recruitment of noninfected endothelial cell into the KS lesion; (c) LANA+/CD34- cells were more frequent in early as compared to late KS and most of them expressed LEC markers such as LYVE-1 and D2-40, suggesting that the resident LECs represent an early target of primary HHV-8 infection; (d) LANA+/CD34-/LYVE-1+ cells decreased from early (25%) to late (4%) KS suggesting a phenotype switch from LEC to VEC; (e) the frequency of proliferating cells (Ki67+) was higher in early as compared to late KS stages and no significant difference in cell proliferation was observed between nodular AKS and EKS, suggesting that the growth of the usually more aggressive AKS tumors may reflect a higher rate of SC progenitor recruitment as compared to the slower growing EKS lesions, consistent with the observed increase in non-proliferative SC during KS (AKS) evolution to nodular stage; (f) infiltrating lymphocytes were LANA negative, whereas some CD68+ monocyte-macrophase appeared to be LANA+.To validate our results from LANA immunostaining, we established and optimized a semi-quantitative PCR assay for HHV-8 detection in formalin-fixed paraffin-embedded KS biopsies (paper III) and two different protocols for DNA extraction were compared namely the Chelex 100 and Qia-gene kit method. Our result indicate a better performance for Chelex-extracted DNA in paraffin embedded archival biopsies. In late, nodular stage of both AKS and EKS the virus load per unit tissue actin (HHV-8/actin) is higher than in early stages (patch/plaque), which corroborates our findings from double immunostaining for LANA and CD34 of the same cases. Thus these PCR results by serial dilutions of HHV-8 DNA show a correlation between virus load and progressive stages of KS development i.e. the increase in LANA+ SC and does not indicate an increase in viral content of individual tumor cells.With quantitative real time PCR on sera (paper II), we found higher HHV8 DNA load in AKS compared to EKS, patch compared to nodular KS and males compared to females as well as a significantly higher serum viral DNA load in KS compared to non-KS patients’ sera.AKS patient sera studied by ELISA for HIV-Tat antibodies showed that patients with high HHV8-DNA level had no or low levels of anti-Tat antibodies while patients with very low HHV8-DNA levels had several fold higher anti-Tat IgG titers. Analysis of these KS sera for epitope specificity showed reactivity to various Tat epitopes but not to the transcriptional (functional) epitopes 46-60 (TAR-binding region). To determine cytogenetic changes during the development of KS as well as possible differences between AKS and EKS we studied 27 KS (10 nodular AKS, 8 patch AKS, 8 nodular EKS and 1 patch EKS) cases by laser microdissection, global amplification of DNA and comparative genomic hybridization (paper IV). Deletion of Chromosome Y was detected in 20 of 23 male KS and was the only chromosomal deletion observed in early (patch) KS biopsies. Late AKS and EKS apart from random aberrations also showed recurrent chromosomal deletions of chromosome 16, 17, Y and a gain of chromosome 21. The deletion of chromosome 16 and Y was confirmed by interphase FISH on paraffin embedded sections. EKS had higher number of chromosomal abnormalities than AKS.In summary KS SC apparently represents a mixed pool endothelial cells including cells from both VEC and LEC the later being a possible early target for HHV-8 infection. Non-infected CD34+ progenitor cells appears to be continuously recruited to the developing KS lesion and locally infected during the development of KS. Serum HHV-8 DNA load is higher in AKS compared to EKS and HIV-Tat titers were inversely correlated to HHV-8 DNA load in AKS patients. Increased number of recurrent and sporadic chromosomal abnormalities found mostly in a subset of late nodular KS cases may indicate the onset of a clonal cell population (sarcoma).List of scientific papersI. Pyakurel P, Massambu C, Castanos-Velez E, Ericsson S, Kaaya E, Biberfeld P, Heiden T (2004). Human herpesvirus 8/Kaposi sarcoma herpesvirus cell association during evolution of Kaposi sarcoma. J Acquir Immune Defic Syndr. 36(2): 678-83. https://doi.org/10.1097/00126334-200406010-00004 II. Massambu C, Pyakurel P, Kaaya E, Enbom M, Urassa W, Demirhan I, Loewer J, Linde A, Chandra A, Heiden T, Doerr HW, Chandra P, Biberfeld P (2003). Serum HHV8 DNA and Tat antibodies in Kaposis sarcoma patients with and without HIV-1 infection. Anticancer Res. 23(3B): 2389-95. https://pubmed.ncbi.nlm.nih.gov/12894519 III. Pak F, Pyakural P, Kokhaei P, Kaaya E, Akbar Pourfathollah A, Selinova G, Biberfeld P (2005). HHV-8/KSHV during development of Kaposis sarcoma: evaluation by PCR and immunohistochemistry. J Cutan Pathol. 32(1): 21-7. https://doi.org/10.1111/j.0303-6987.2005.00256.x IV. Pyakurel P, Montag U, Castanos-Velez E, Kaaya E, Christensson B, Biberfeld P, Schrock E, Heiden T (2005). Kaposis sarcoma: CGH ctogenetic analysis of microdissected early and late stage biopsies. [Manuscript]V. Pyakurel P, Pak F, Mwakigonja AR, Kaaya E, Heiden T, Biberfeld P (2005). Recruitment of Kaposis sarcoma spindle cells during tumor development. [Manuscript]</p
Orchids in Rolpa district of Western Nepal: Documentation, stock, trade and conservation
No full textOrchids are perennial, epiphytic, terrestrial or lithophytic herbs with roots having multilayered spongy tissues. In Nepal, 363 species of orchids are organized into 97 genera. Orchids fall under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix II but do not fall under the legal protection of any existing national legislation. Habitat loss, forest destruction and degradation and over-exploitation have posed threats to the conservation of orchids in Nepal. The current study aims to document the orchids and estimate the stock of Dendrobium denudans and Dendrobium eriiflorum in a few potential locations of Rolpa district. A total of 36 species were documented in the surveyed 17 Village Development Committees (VDCs). Among them, 31 species were identified up to species level, two species up to generic level and the remaining three were unidentifed. The total stock of D. denudans was highest in Uwa VDC with 11018.08 kg followed by Seram VDC with the stock of 9982.57 kg. Similarly, D. eriiflorum stock in Seram, Siuri and Jaimakasala VDCs were 22750.01 kg, 7039.67 kg and 4933.46 kg, respectively. This study recommends a systematic research on the propagation technique; complete indexing of orchids; and inclusion of orchids in the Red Data Book on the threatened and endangered species. Orchid reserves in orchid hotspots should be established for the preservation and promotion of regeneration activities. The rare and endangered species should be preserved in botanic gardens. In addition to scientific attempts, the country should launch and implement a very firm regulation for their protection. Key words: Orchids; Dendrobium denudans; Dendrobium eriiflorum; distribution; conservation; Rolpa district DOI: 10.3126/banko.v20i2.4796 Banko Janakari Vol.20(2) 2010 pp.3-13</jats:p
Automated urinalysis: First experiences and comparison of automated urinalysis system and manual microscopy
No full textBackground: Urinary tract infection is a common condition which needs laboratory evaluation of urine to substantiate the clinical diagnosis and initiate treatment. The conventional urinalysis consists of using a test strip for chemical examination to identify the various urine sediments after which visual microscopy is done. We evaluate the analytical performance of automated microscopic technique (UF 500i) and compare results with those from manual microscopy. Materials and Methods: A total of 382 urine specimens were collected during a period of one month out of which 128 samples which had abnormal cell counts were analyzed for cells and particles by manual and automated microscopy by UF-500i flow cytometer. Results: The concordance of UF 500i and the manual microscopy which is considered to be the gold standard for urine microscopic examination was 90.6% for white blood cells, red blood cell, epithelial cells, cast and bacterial count. Conclusion: Automated urine sediment analyzer, UF 500i was considered reliable in the measurement of white blood cells, red blood cells, epithelial cells, cast and bacteria. Automation will surely reduce the work load, increase accuracy and reliability, and increase the throughput and turn-around time of the laboratory DOI: http://dx.doi.org/10.3126/jpn.v4i7.10316 Journal of Pathology of Nepal (2014) Vol. 4, 576-579 </p
AIDS and endemic Kaposi's sarcoma development : comparison by histopathology, virology (HHV8/KSHV) and cytogenetics [Elektronisk resurs]
No full textKaposi’s sarcoma (KS) is a highly and abnormally vascularized tumor-like lesion with spindle cells (SC) affecting the skin, lymphnodes and viscera which is found in four different clinico-epidemiological forms as Classic KS (CKS), Iatrogenic KS (IKS), Endemic KS (EKS) and AIDS-associated KS (AKS). All KS forms develop from early stages of patch/plaque to late, nodular tumors and are associated with Kaposi's sarcomaassociated herpesvirus or human herpesvirus-8 (KSHV/ HHV-8). HHV-8 is also associated with primary effusion lymphoma (PEL) and multicentric castleman's disease (MCD). Various studies favour an endothelial origin (CD34+) of the KS SC but whether of vascular (VEC) or lymphatic endothelial cell (LEC) origin has not been settled. The HHV-8 latency-associated nuclear antigen type 1 (LANA-1) protein is the most frequently expressed viral antigen in infected cells. KS is promoted by HIV infection mainly by the angiogenic and proinflammatory effects of HIV-Tat. Whether KS represents a predominantly monoclonal neoplastic cell proliferation or a hyperplastic, reactive polyclonal process is still controversial. Reports on cytogenetic and molecular genetic changes in KS are few indicating that initially KS may develop as a reactive polyclonal cell proliferation associated with chromosome instability, followed by clonal chromosome changes in later stages. In the present KS histopathological studies (paper I & V) by triple antibody immunofluorescence we observed that: (a) the frequency of LANA+/CD34+ cells increased from early patch to late KS nodular lesions; (b) 30- 40% of the CD34+ SC were LANA- in both early and late KS, suggesting a continuous recruitment of noninfected endothelial cell into the KS lesion; (c) LANA+/CD34- cells were more frequent in early as compared to late KS and most of them expressed LEC markers such as LYVE-1 and D2-40, suggesting that the resident LECs represent an early target of primary HHV-8 infection; (d) LANA+/CD34-/LYVE-1+ cells decreased from early (25%) to late (4%) KS suggesting a phenotype switch from LEC to VEC; (e) the frequency of proliferating cells (Ki67+) was higher in early as compared to late KS stages and no significant difference in cell proliferation was observed between nodular AKS and EKS, suggesting that the growth of the usually more aggressive AKS tumors may reflect a higher rate of SC progenitor recruitment as compared to the slower growing EKS lesions, consistent with the observed increase in non-proliferative SC during KS (AKS) evolution to nodular stage; (f) infiltrating lymphocytes were LANA negative, whereas some CD68+ monocyte-macrophase appeared to be LANA+. To validate our results from LANA immunostaining, we established and optimized a semi-quantitative PCR assay for HHV-8 detection in formalin-fixed paraffin-embedded KS biopsies (paper III) and two different protocols for DNA extraction were compared namely the Chelex 100 and Qia-gene kit method. Our result indicate a better performance for Chelex-extracted DNA in paraffin embedded archival biopsies. In late, nodular stage of both AKS and EKS the virus load per unit tissue actin (HHV-8/actin) is higher than in early stages (patch/plaque), which corroborates our findings from double immunostaining for LANA and CD34 of the same cases. Thus these PCR results by serial dilutions of HHV-8 DNA show a correlation between virus load and progressive stages of KS development i.e. the increase in LANA+ SC and does not indicate an increase in viral content of individual tumor cells. With quantitative real time PCR on sera (paper II), we found higher HHV8 DNA load in AKS compared to EKS, patch compared to nodular KS and males compared to females as well as a significantly higher serum viral DNA load in KS compared to non-KS patients’ sera. AKS patient sera studied by ELISA for HIV-Tat antibodies showed that patients with high HHV8-DNA level had no or low levels of anti-Tat antibodies while patients with very low HHV8-DNA levels had several fold higher anti-Tat IgG titers. Analysis of these KS sera for epitope specificity showed reactivity to various Tat epitopes but not to the transcriptional (functional) epitopes 46-60 (TAR-binding region). To determine cytogenetic changes during the development of KS as well as possible differences between AKS and EKS we studied 27 KS (10 nodular AKS, 8 patch AKS, 8 nodular EKS and 1 patch EKS) cases by laser microdissection, global amplification of DNA and comparative genomic hybridization (paper IV). Deletion of Chromosome Y was detected in 20 of 23 male KS and was the only chromosomal deletion observed in early (patch) KS biopsies. Late AKS and EKS apart from random aberrations also showed recurrent chromosomal deletions of chromosome 16, 17, Y and a gain of chromosome 21. The deletion of chromosome 16 and Y was confirmed by interphase FISH on paraffin embedded sections. EKS had higher number of chromosomal abnormalities than AKS. In summary KS SC apparently represents a mixed pool endothelial cells including cells from both VEC and LEC the later being a possible early target for HHV-8 infection. Non-infected CD34+ progenitor cells appears to be continuously recruited to the developing KS lesion and locally infected during the development of KS. Serum HHV-8 DNA load is higher in AKS compared to EKS and HIV-Tat titers were inversely correlated to HHV-8 DNA load in AKS patients. Increased number of recurrent and sporadic chromosomal abnormalities found mostly in a subset of late nodular KS cases may indicate the onset of a clonal cell population (sarcoma)
Leaf morphological and anatomical variations of paper birch populations along environmental gradients across Canada
No full textLeaf morphology and anatomy have been found to vary considerably among tree
species, and leaf characteristics have widely been used for analyzing plant growth and
resource use strategies because of their structural adaptation to withstand environments.
Considering the changing climate projections, early-successional, broad niched species
like paper birch (Betula papyrifera Marsh.) are expected to increase dominance due to a
zonal shift of natural vegetation and/or open gaps within the current vegetation zones.
Hence, it is important to understand factors such as leaf characteristics that enable these
pioneer species to inhabit a wide geographic range and their increasing dominance.
Paper birch is a pioneer tree species in North America that inhabits wide climatic
and geographic gradients; in addition, the species has developed different leaf
morphology and anatomy that have allowed paper birch to adapt to diverse habitats. This
study examines how the leaf characteristics of paper birch vary under uniform and
stressed environments. The major objectives were (a) to investigate leaf characteristics
variations in paper birch populations grown in uniform environmental conditions as in a
greenhouse and a common garden; (b) to correlate between leaf characteristics and paper
birch’s environment of origins; (c) to investigate leaf characteristic variations in paper
birch populations grown under different carbon dioxide concentrations [CO2] and soil
water levels to determine the relationship between leaf characteristics and individual or
interacting effects of [CO2], water levels and populations; and (d) to analyze the
relationship within and between leaf morphology and anatomy of the birch populations.
The study found significant differences among paper birch populations in leaf
morphological characteristics under a uniform environment at the greenhouse and the
common garden. The leaf characteristic variations in the uniform environment may be
related to the different genotypes of the birch inhabiting a wide environmental gradient.
In paper birch populations grown in the common garden, significant differences in
stomatal density, stomatal area, pore area and guard cell width were identified. As
expected, the birch populations in greenhouse and common garden environments
showed significant correlations of leaf characteristics, namely specific leaf area (SLA),
leaf maximum width index and petiole area to latitude, longitude, elevation, temperature,
precipitation and aridity index of origin. Correlation between leaf characteristics of
paper birch in the greenhouse showed that populations originated in limited precipitation
(during growing season) had low hair density on leaf adaxial surface, with larger leaf
width and petiole area. Birch populations grown in the common garden revealed that
populations originated in higher mean annual precipitation had less hair density on leaf
adaxial surface with smaller leaf area and higher stomatal density. Relationships within
the leaf characteristics revealed significant correlations within and between leaf morphology and anatomy as populations with larger leaf area had larger petiole area and
less adaxial hair density in greenhouse. The larger petiole in larger leaf reflects the need
for mechanical strengthening to support, whereas inverse relationship between leaf area
and hair density possibly showed a strategy of the birch to balance water loss. In
common garden, the birch populations with larger leaf area had larger specific leaf area
and higher adaxial hair density but low stomatal density. All these features in paper
birch populations provide a structural basis for reducing water loss through leaves and
increasing water use efficiency. There was no consistency in leaf characteristics when
the paper birch populations were grown in uniform environments as in the greenhouse
and the common garden.
Analysis of the leaf characteristics in the birch showed significant differences due
to the interaction and/or main effects of [CO2], water levels and populations. Paper birch
had decreased leaf area and increased stomatal density under elevated [CO2] which might
have reduced stomatal conductance and increased water-use efficiency. Under low soil
water level, paper birch populations studied had smaller stomatal area, pore area and
guard cell width. Contrasting with the expectation neither stomatal area was larger nor
stomatal density increased under low water level. A trade-off between stomatal area and
density in this study showed that stomatal area per unit leaf area remained the same.
Hence, smaller stomatal area and guard cell width under low water level must have
improved [CO2
] diffusion and decreased water loss compared to larger stomatal area and
guard cell width.
The results of this study confirmed significant genotypic difference in leaf
characteristics of paper birch populations irrespective of a uniform growing
environment. The characteristics, namely leaf area, maximum width, SLA, stomatal
density and stomatal area, appear related to the environment of origin; however, these
relationships were not consistent in the birch populations grown in the greenhouse and
common garden. Paper birch populations acclimated to the uniform environments;
differences in leaf area, stomatal density and stomatal area in paper birch populations
under different [CO2] and soil water levels prove the birch’s ability to acclimate to
environmental changes. Lastly, integration of leaf morphology and anatomy enhanced
paper birch’s ability to balance between [CO2] gain and water loss
A study on microvascular density in breast carcinoma
No full textBackground: Breast Cancer is the most frequent neoplasm causing death in women between 35-55 years of age. Of the Prognostic indicators existing for breast cancer, axillary lymph node status has been regarded as the most important one. Twenty to thirty percent of all lymph node negative patients will still develop a recurrence of the disease within 10 years of initial treatment. Therefore, a new prognostic marker that could identify patients at high risk of tumor recurrence more accurately than existing indicators would be of great value, one potential indicator is tumor-induced angiogenesis. Materials and Methods: This is a six months prospective (January 2010-June 2010) and 1 year retrospective (Jan2009-Dec2009) study which included thirty five breast cancer cases visiting the Surgical OPD. Angiogenesis was estimated by determining micro vessel counting after immune staining the paraffin embedded tissue sections using anti-CD34 antibody. Results: Age of the patients ranged from 25 to 80 years with a mean age of 45.48 years. Most of the cases were infiltrating ductal carcinoma comprising of 33 cases (94.28%). Three cases (9.10%) showed vascular invasion by the tumor. Majority showed (63.64%) vessel count of less than 200 per 10 high power fields. Conclusion: Micro vascular density positively correlated with size of the tumor, lymph nodes involved by the tumor and Nottingham prognostic index. In the future, Antibodies specific to proliferating endothelium, together with the development of automated image analysis, may improve the accuracy and value of measuring angiogenesis-induced microvessel density. DOI: http://dx.doi.org/10.3126/jpn.v4i7.10315 Journal of Pathology of Nepal (2014) Vol. 4, 570-575 </p
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