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Articles by S Gupta
Total Records ( 7 ) for S Gupta
  S Gupta , O Fiertag and J. Warner
 

Over 95% of cases of dementia are attributable to Alzheimer’s disease, vascular, Lewy body and fronto-temporal dementia, and a few other common causes. In this article we consider some of the rare and unusual causes that account for the remaining 5%. Categorising them according to aetiological group (degenerative, vascular and infectious causes, and human prion diseases), we discuss the presentation of these forms and reasons for variations in estimated prevalence rates in the general population.

  D Zhang , X Jiang , P Fang , Y Yan , J Song , S Gupta , A. I Schafer , W Durante , W. D Kruger , X Yang and H. Wang
 

Background— Hyperhomocysteinemia (HHcy) is an independent risk factor for cardiovascular disease. Monocytes display inflammatory and resident subsets and commit to specific functions in atherogenesis. In this study, we examined the hypothesis that HHcy modulates monocyte heterogeneity and leads to atherosclerosis.

Methods and Results— We established a novel atherosclerosis-susceptible mouse model with both severe HHcy and hypercholesterolemia in which the mouse cystathionine β-synthase (CBS) and apolipoprotein E (apoE) genes are deficient and an inducible human CBS transgene is introduced to circumvent the neonatal lethality of the CBS deficiency (Tg-hCBS apoE–/– Cbs–/– mice). Severe HHcy accelerated atherosclerosis and inflammatory monocyte/macrophage accumulation in lesions and increased plasma tumor necrosis factor- and monocyte chemoattractant protein-1 levels in Tg-hCBS apoE–/– Cbs–/– mice fed a high-fat diet. Furthermore, we characterized monocyte heterogeneity in Tg-hCBS apoE–/– Cbs–/– mice and another severe HHcy mouse model (Tg-S466L Cbs–/–) with a disease-relevant mutation (Tg-S466L) that lacks hyperlipidemia. HHcy increased monocyte population and selective expansion of inflammatory Ly-6Chi and Ly-6Cmid monocyte subsets in blood, spleen, and bone marrow of Tg-S466L Cbs–/– and Tg-hCBS apoE–/– Cbs–/– mice. These changes were exacerbated in Tg-S466L Cbs–/– mice with aging. Addition of l-homocysteine (100 to 500 µmol/L), but not l-cysteine, maintained the Ly-6Chi subset and induced the Ly-6Cmid subset in cultured mouse primary splenocytes. Homocysteine-induced differentiation of the Ly-6Cmid subset was prevented by catalase plus superoxide dismutase and the NAD(P)H oxidase inhibitor apocynin.

Conclusion— HHcy promotes differentiation of inflammatory monocyte subsets and their accumulation in atherosclerotic lesions via NAD(P)H oxidase–mediated oxidant stress.

  A. T Hooper , S. V Shmelkov , S Gupta , T Milde , K Bambino , K Gillen , M Goetz , S Chavala , M Baljevic , A. J Murphy , D. M Valenzuela , N. W Gale , G Thurston , G. D Yancopoulos , L Vahdat , T Evans and S. Rafii
 

Blood vessel formation is controlled by the balance between pro- and antiangiogenic pathways. Although much is known about the factors that drive sprouting of neovessels, the factors that stabilize and pattern neovessels are undefined. The expression of angiomodulin (AGM), a vascular endothelial growth factor (VEGF)-A binding protein, was increased in the vasculature of several human tumors as compared to normal tissue, raising the hypothesis that AGM may modulate VEGF-A–dependent vascular patterning. To elucidate the expression pattern of AGM, we developed an AGM knockin reporter mouse (AGMlacZ/+), with which we demonstrate that AGM is predominantly expressed in the vasculature of developing embryos and adult organs. During physiological and pathological angiogenesis, AGM is upregulated in the angiogenic vasculature. Using the zebrafish model, we found that AGM is restricted to developing vasculature by 17 to 22 hours postfertilization. Blockade of AGM activity with morpholino oligomers results in prominent angiogenesis defects in vascular sprouting and remodeling. Concurrent knockdown of both AGM and VEGF-A results in synergistic angiogenesis defects. When VEGF-A is overexpressed, the compensatory induction of the VEGF-A receptor, VEGFR2/flk-1, is blocked by the simultaneous injection of AGM morpholino oligomers. These results demonstrate that the vascular-specific marker AGM modulates vascular remodeling in part by temporizing the proangiogenic effects of VEGF-A.

  S. C Kim , J. P Stice , L Chen , J. S Jung , S Gupta , Y Wang , G Baumgarten , J Trial and A. A. Knowlton
 

Rationale: Previously, we have found that changes in the location of intracellular heat shock protein (HSP)60 are associated with apoptosis. HSP60 has been reported to be a ligand of Toll-like receptor (TLR)-4.

Objective: We hypothesized that extracellular HSP60 (exHSP60) would mediate apoptosis via TLR4.

Methods and Results: Adult rat cardiac myocytes were treated with HSP60, either recombinant human or with HSP60 purified from the media of injured rat cardiac myocytes. ExHSP60 induced apoptosis in cardiac myocytes, as detected by increased caspase 3 activity and increased DNA fragmentation. Apoptosis could be reduced by blocking antibodies to TLR4 and by nuclear factor B binding decoys, but not completely inhibited, even though similar treatment blocked lipopolysaccharide-induced apoptosis. Three distinct controls showed no evidence for involvement of a ligand other than exHSP60 in the mediation of apoptosis.

Conclusions: This is the first report of HSP60-induced apoptosis via the TLRs. HSP60-mediated activation of TLR4 may be a mechanism of myocyte loss in heart failure, where HSP60 has been detected in the plasma.

  D. J Stewart , J. P Issa , R Kurzrock , M. I Nunez , J Jelinek , D Hong , Y Oki , Z Guo , S Gupta and I. I. Wistuba
 

Purpose: By hypomethylating genes, decitabine may up-regulate factors required for chemotherapeutic cytotoxicity. Platinum-resistant cells may have reduced expression of the copper/platinum transporter CTR1.

Experimental Design: Thirty-one patients with refractory malignancies received decitabine 2.5 to 10 mg/m2 on days 1 to 5, and 8 to 12 or 15 to 20 mg/m2 on days 1 to 5. Tumor was assessed for DNA methylation (by LINE assays), apoptosis, necrosis, mitoses, Ki67, DNA methyltransferase (DNMT1), CTR1, and p16.

Results: Febrile neutropenia was dose limiting. One thymoma patient responded. Decitabine decreased tumor DNA methylation (from median 51.2% predecitabine to 43.7% postdecitabine; P = 0.01, with effects at all doses) and in peripheral blood mononuclear cells (from 65.3-56.0%). There was no correlation between tumor and peripheral blood mononuclear cells. Patients starting decitabine ≤3 versus >3 months after last prior cytotoxic or targeted therapy had lower predecitabine tumor CTR1 scores (P = 0.02), higher p16 (P = 0.04), and trends (P = 0.07) toward higher tumor methylation and apoptosis. Decitabine decreased tumor DNMT1 for scores initially >0 (P = 0.04). Decitabine increased tumor apoptosis (P < 0.05), mitoses (if initially low, P = 0.02), and CTR1 (if initially low, P = 0.025, or if ≤3 months from last prior therapy, P = 0.04). Tumor CTR1 scores correlated inversely with methylation (r = –0.41, P = 0.005), but CTR1 promoter was not hypermethylated. Only three patients had tumor p16 promoter hypermethylation. P16 scores did not increase. Higher blood pressure correlated with lower tumor necrosis (P = 0.03) and a trend toward greater DNA demethylation (P = 0.10).

Conclusions: Exposure to various cytotoxic and targeted agents might generate broad pleiotropic resistance by reducing CTR1 and other transporters. Decitabine decreases DNA methylation and augments CTR1 expression through methylation-independent mechanisms.

  D. H. J Elder , M Pauriah , C. C Lang , J Shand , I. B. A Menown , B. D. W. C. K Sin , S Gupta , S. G Duckett , W Foster , D Zachariah and P. R. Kalra
 

Background: In the management of chronic stable angina, percutaneous coronary intervention (PCI) provides symptomatic relief of angina rather than improvement of prognosis. Current guidelines recommend optimization of medical therapy prior to elective PCI. It is not clear if these guidelines are adhered to in clinical practice.

Aim: The aim of this multi-centre study was to determine the extent to which these treatment guidelines are being implemented in the UK.

Design: This was a multi-centre study involving six hospitals in the UK.

Methods: The medical treatment and extent of risk factor modification was recorded for consecutive patients undergoing elective PCI for chronic stable angina at each site. Data collected included anti-anginal drug therapy, lipid levels and blood pressure (BP). Data on heart rate (HR) control were also collected, since this represents a fundamental part of medical anti-anginal therapy. Target HR is <60 b.p.m. for symptomatic angina.

Results: A total of 500 patients [74% male; mean age ± SD (64.4 ± 10.1 years)] were included. When considering secondary prevention, 85% were receiving a statin and 76% were on an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. In terms of medical anti-ischaemic therapy, 78% were receiving beta-blockers [mean equivalent dose of bisoprolol 3.1 mg (range 1.25–20 mg)], 11% a rate limiting calcium antagonist, 35% a nitrate or nicorandil and one patient was receiving ivabradine. The mean total cholesterol (95% confidence interval) was 4.3 mmol/l (4.2–4.4), mean systolic BP of 130 ± 24 mmHg and mean diastolic BP of 69 ± 13 mmHg. Serum cholesterol was <5 mmol/l in 77% and <4 mmol/l in 42% of the patients, 62% of the patients had systolic BP < 140 mmHg and 92% had diastolic BP < 90 mmHg. Considering European Society of Cardiology targets, 50% had systolic BP < 130 mmHg and 76% had diastolic BP < 80 mmHg. A large proportion of patients did not achieve target resting HR; 27% of patients had a resting HR of >=70 b.p.m., 40% had a resting HR between 60 and 69 b.p.m. and 26% had a resting HR between 50 and 59 b.p.m. The resting HR was not related to the dose of beta-blocker.

Conclusions: A significant proportion of the patients with chronic stable angina undergoing elective PCI did not achieve therapeutic targets for lipid, BP and HR control. Over 50% of patients did not receive adequate HR lowering anti-anginal therapy to achieve recommended target resting HR.

 
 
 
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