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author:("Shah, ripas")
1.  Hexamers of the Type II Secretion ATPase GspE from Vibrio cholerae with Increased ATPase Activity 
Structure (London, England : 1993)  2013;21(9):1707-1717.
The Type II Secretion System (T2SS), a multi-protein machinery spanning two membranes in Gram-negative bacteria, is responsible for the secretion of folded proteins from the periplasm across the outer membrane. The critical multi-domain T2SS assembly ATPase GspEEpsE had so far not been structurally characterized as a hexamer. Here, four hexamers of Vibrio cholerae GspEEpsE are obtained when fused to Hcp1 as an assistant hexamer, as shown by native mass spectrometry. The enzymatic activity of the GspEEpsE-Hcp1 fusions is ~20 times higher than that of a GspEEpsE monomer indicating that increasing the local concentration of GspEEpsE by the fusion strategy was successful. Crystal structures of GspEEpsE-Hcp1 fusions with different linker lengths reveal regular and elongated hexamers of GspEEpsE with major differences in domain orientation within subunits, and in subunit assembly. SAXS studies on GspEEpsE-Hcp1 fusions suggest that even further variability in GspEEpsE hexamer architecture is likely.
PMCID: PMC3775503  PMID: 23954505
2.  Analysis of efforts to maintain safe donor in main donor pool after completion of temporary deferral period 
Voluntary blood donation is not satisfactory all over India. In India, about 55% of donation is through voluntary non-remunerated blood donors (VNRBD). However, about one third already motivated blood donors are deferred due to stringent screening criteria, either temporarily or permanently. The temporarily deferred donors could be a good source of blood donation after deferral period.
The present study is carried out to know retrieval of blood donors those who are deferred temporarily.
The present study is carried out in the Regional Blood Transfusion Centre of Western India. All donors screened as per the guideline and deferred donors are categorized as temporary and permanently deferred donors.
Materials and Methods:
From temporarily deferred donors, reason for deferral is considered. As per reason of deferral, time duration for recalling the donor is defined. Based on this, donor is called back to donate again.
Statistical Analysis:
Chi-square test is applied.
A total of 33% donors were deferred either temporarily or permanently. In the repeat donors (5.32%) deferral rate was significantly higher than first time (1.32%) donors. Significant female preponderance was observed (15.05% vs 2.51%). Majority of temporarily deferred donors were less than 40 years of age (80.80%), graduate (82.90%), from low income group (62.90%) and profession was service (48.10%).
Low hemoglobin (78.30%) was the most common reason of temporary deferral, both in first time and repeat donors (71.00%). Efforts to increase the hemoglobin in the repeat donors will improve the donor retention and overall blood safety can be increased.
PMCID: PMC3613667  PMID: 23559769
Donor return; hemoglobin; retrieval; temporary deferral; voluntary non-remunerated blood donors/ blood donor
3.  True positivity of anti-Hepatitis C Virus Enzyme-linked immunosorbent assay reactive blood donors: A prospective study done in western India 
A significant number of safe donations are removed from the blood supply, because of the reactive anti-HCV screening test results. This study aimed to assess if the HCV (Hepatitis C Virus) seropositive donors were confirmed positive or not.
Materials and Methods:
More than 68,000 blood donors’ samples were routinely screened and 140 samples were found to be anti-HCV ELISA reactive. These 140 samples were tested by NAT. The NAT negative samples were tested by RIBA. Analysis of samples reactive in single ELISA kit vs. two ELISA kits was done.
Out of 140 anti-HCV ELISA reactive samples, a total of 16 (11.43%) were positive by NAT. The results of 124 RIBA showed 6 (4.84%) positive, 92 (74.19%) negative, and 26 (20.97%) indeterminate results. None of the sample which was reactive in only single ELISA kit was positive by NAT or RIBA.
Only a minority of blood donors with repeatedly reactive anti-HCV screening test is positive by confirmatory testing, but all these blood units are discarded as per existing legal provisions in India. Efforts should be made to retain these donors and also donor units.
PMCID: PMC3439757  PMID: 22988383
Anti-Hepatitis C Virus Enzyme-linked immunosorbent assay; nucleic acid amplification test; recombinant immuno blot assay
4.  Deferral pattern in voluntary blood donors on basis of low hemoglobin and effect of application of digital hemoglobinometer on this pattern 
One of the responsibilities of blood center is to provide safety to blood donors. It is mandatory to screen a blood donor for hemoglobin (Hb) or hematocrit which should not be less than 12.5 g/dl or 38% Hct. Most commonly applied method for hemoglobin estimation is copper sulphate method, but this method has chances of false acceptance as well as false deferral. In order to avoid this chance of error, digital hemoglobinometer is used. This study was planned to analyze effect of application of digital hemoglobinometer for detection of Hb on donors, who are deferred by copper sulphate method.
Materials and Methods:
Total 35,339 voluntary non renumareted altruistic donors were included in this study between the periods of September 2005 to July 2006. Total deferred donors were 8622 (24.39%) and donors deferred due to hemoglobin by copper sulphate method were 4391 (50.92%). Digital hemoglobinometer was applied on 3163 deferred donors (72.03%). Results of digital hemoglobinometer were validated by known controls.
Digital hemoglobinometer was applied on 3163 donors who were deferred by copper sulphate method. Out of this, donors accepted by digital hemoglobinometer were 1196 (37.01%). Total repeat donors were 629 (52.50%) and first time were 567 (47.40%). Male donors were 891 (74.44%) and females were 305 (25.50%). Donors deferred with digital hemoglobinometer were 2135, out of them 1097 (51.14%) were repeat, 1038 (48.38%) were first time, 1349 (60.79%) were male, 786 (34.47%) donors were female donors. Range of hemoglobin in deferred donors was 7.0 to 12.4 and in accepted donors 12.5 to 16.4.
By the application of digital hemoglobinometer 37.81% donors were found hemoglobin >12.5 which were deferred with copper sulphate method and unnecessary deferral of donors can be reduced to a great extent. In country like India, where blood supply is always less than the requirement, this new technique may be helpful to increase donor population but cost benefit ratio should be analyzed.
PMCID: PMC3439760  PMID: 22988386
Copper sulphate; digital hemoglobinometer; hemoglobin
7.  Serial follow-up of repeat voluntary blood donors reactive for anti-HCV ELISA 
Voluntary non-remunerated repeat blood donors are perceived to be safer than the first time blood donors. This study was planned for follow-up of previous hepatitis C virus (HCV) test results of anti-HCV enzyme-linked immunosorbent assay (ELISA) reactive repeat blood donors. The aim was to suggest a protocol for re-entry of the blood donors who are confirmed HCV negative by nucleic acid test (NAT) and recombinant immunoblot assay (RIBA). A group of repeat voluntary donors were followed retrospectively who became reactive on a cross sectional study and showed HCV reactivity while donating blood regularly.
Material and Methods:
A total of 51,023 voluntary non remunerated blood donors were screened for anti-HCV ELISA routinely. If anybody showed positivity, they were tested by two ELISA kits (screening and confirmatory) and then confirmed infection status by NAT and or RIBA. The previous HCV test results of repeat donors reactive by anti-HCV ELISA were looked back from the records. Data of donors who were repeat reactive with single ELISA kit (in the present study) were analyzed separately from those reactive with two ELISA kits (in the present study).
In this study, 140 (0.27%) donors who were reactive by anti HCV ELISA were included. Out of them, 35 were repeat voluntary donors and 16 (11.43%) were reactive with single ELISA kit. All 16 donors were reactive by single ELISA kit occasionally in previous donations. Their present ELISA positive donations were negative for HCV NAT and RIBA. A total of 19 (13.57%) donors were reactive with two ELISA kits. In their previous donations, the donors who were reactive even once with two ELISA kits were consistently reactive by the same two ELISA kits in their next donations also.
Donor sample reactive by only single ELISA kit may not be considered as infectious for disposal as they were negative by NAT and or RIBA. One time ELISA positivity was found probably due to ELISA kit specificity and sensitivity. Donors reactive with two ELISA kit should be discarded as there is a high positivity with NAT/ RIBA. However, donors reactive by two ELISA kits and negative by NAT and RIBA should be followed up and may not be deferred permanently.
PMCID: PMC3082711  PMID: 21572711
Anti-HCV ELISA; repeat voluntary blood donor; occult infections; donor follow-up; nucleic acid test; recombinant immunoblot assay
8.  Drosophila Follistatin Exhibits Unique Structural Modifications and Interacts with Several TGF-Beta Family Members 
Mechanisms of development  2007;125(1-2):117-129.
Follistatin (FS) is one of several secreted proteins that modulate the activity of TGF-β family members during development. The structural and functional analysis of Drosophila Follistatin (dFS) reveals important differences between dFS and its vertebrate orthologues: it is larger, more positively charged, and proteolytically processed. dFS primarily inhibits signaling of Drosophila Activin (dACT) but can also inhibit other ligands like Decapentaplegic (DPP). In contrast, the presence of dFS enhances signaling of the Activin-like protein Dawdle (DAW), indicating that dFS exhibits a dual function in facilitating and inhibiting signaling of TGF-β ligands. In addition, FS proteins may also function in facilitating ligand diffusion. We find that mutants of daw are rescued in significant numbers by expression of vertebrate FS proteins. Since two PiggyBac insertions in dfs are not lethal, it appears that the function of dFS is non-essential or functionally redundant.
PMCID: PMC2278114  PMID: 18077144
Follistatin; TGF-beta; Drosophila Activin; Dawdle; DPP; Myoglianin; growth control; heparin sulfate
9.  Mice Lacking Homer 1 Exhibit a Skeletal Myopathy Characterized by Abnormal Transient Receptor Potential Channel Activity▿ † 
Molecular and Cellular Biology  2008;28(8):2637-2647.
Transient receptor potential (TRP) channels are nonselective cation channels, several of which are expressed in striated muscle. Because the scaffolding protein Homer 1 has been implicated in TRP channel regulation, we hypothesized that Homer proteins play a significant role in skeletal muscle function. Mice lacking Homer 1 exhibited a myopathy characterized by decreased muscle fiber cross-sectional area and decreased skeletal muscle force generation. Homer 1 knockout myotubes displayed increased basal current density and spontaneous cation influx. This spontaneous cation influx in Homer 1 knockout myotubes was blocked by reexpression of Homer 1b, but not Homer 1a, and by gene silencing of TRPC1. Moreover, diminished Homer 1 expression in mouse models of Duchenne's muscular dystrophy suggests that loss of Homer 1 scaffolding of TRP channels may contribute to the increased stretch-activated channel activity observed in mdx myofibers. These findings provide direct evidence that Homer 1 functions as an important scaffold for TRP channels and regulates mechanotransduction in skeletal muscle.
PMCID: PMC2293116  PMID: 18268005

Results 1-9 (9)