jorge ferrer - Academia.edu (original) (raw)
Papers by jorge ferrer
Journal of Medical Virology, 1995
Florida; the Guaymi from Panama; and the Toba, Chorote, Wichi, and Chulupe of Argentina, belonged... more Florida; the Guaymi from Panama; and the Toba, Chorote, Wichi, and Chulupe of Argentina, belonged to subtype B. The SKIIO/SKI 11 PCR-OR format should facilitate molecular epidemiology studies of HTLV-I1 infection and allow for subtype stratification in assessing the sensitivity and specificity of HTLV detection formats and HTLV-II disease association. o 1995 Wiley-Liss, tnc.
Virology, 2000
DNA was extracted from the peripheral blood of a seropositive, PCR-positive, BLV-infected Holstei... more DNA was extracted from the peripheral blood of a seropositive, PCR-positive, BLV-infected Holstein cow (No. 38) from Argentina. The DNA was amplified via PCR with a series of overlapping primers encompassing the entire BLV proviral DNA. The amplified BLV ARG 38 DNA was cloned, sequenced, and compared phylogenetically to three other full-length BLV sequences. Characterization of its deduced proteins and its relationship to other members of the PTLV/BLV genus of retroviruses are discussed.
American Journal of Veterinary Research, 2001
Cancer Investigation, 2002
A significant number of chronic lymphocytic leukemia, follicular non-Hodgkin&... more A significant number of chronic lymphocytic leukemia, follicular non-Hodgkin's lymphoma and Waldenström's macroglobulinemia patients, treated with fludarabine phosphate (fludarabine), are elderly with diminished renal function. Since the kidney eliminates approximately 60% of fludarabine's primary metabolite (F-ara-A), dose modification is necessary for all patients with impaired renal function including elderly patients. In this study, 22 patients with varying levels of renal function received a single intravenous dose of fludarabine (25 mg/m3), followed one week later by five (one per day) doses that were adjusted according to three predefined creatinine clearance (CLcr) levels. Relationships between renal function and F-ara-A clearance, F-ara-A exposure and F-ara-A--related toxicities were examined. The results demonstrate that total F-ara-A clearance correlated with CLcr and that F-ara-A exposure levels and patient toxicity profiles were similar across treatment groups. The CLcr-based fludarabine dose adjustments used in this study provided reasonably equivalent F-ara-A exposure with acceptable safety in patients with varying degrees of renal function.
Physical Review E, 2010
Lee, Hyungsuk et al. "Molecular origin of strain softening in cross-linked F-actin networks." Phy... more Lee, Hyungsuk et al. "Molecular origin of strain softening in cross-linked F-actin networks." Physical Review E 82.1 (2010): 011919.
Meat Science, 2008
This review deals with distinctive aspects of quality of Argentinean beef in terms of tenderness,... more This review deals with distinctive aspects of quality of Argentinean beef in terms of tenderness, flavour, colour, juiciness, taste, acceptability, lipid content and composition and its resultant nutraceutical characteristics. Differences are due to beef production systems based on temperate or tropical grasslands aimed at shortening the fattening phase as far as possible, with limited or null use of concentrates. However, the effect of limited supplemental feeding is also discussed as well as the responses arising from the use of beef cattle genotypes, including British, Continental, Dairy, Zebu breeds and their crosses, adapted to the various environments and systems found in the country.
Angewandte Chemie, 2007
Single-molecule techniques have been responsible for substantial advances in the field of biophys... more Single-molecule techniques have been responsible for substantial advances in the field of biophysics. Among these approaches, single-molecule fluorescence resonant energy transfer (FRET) spectroscopy provides an experimental view of the structural properties of individual molecules, whereas optical-tweezers force microscopy allows direct manipulation of the reaction coordinate of a single molecule. However, the simultaneous application of these techniques is complicated by optical-trap-induced photobleaching, which substantially reduces fluorophore longevity to unacceptably short timescales. Herein, we describe a general solution to this problem and apply it to a novel force sensor based on a DNA hairpin, in the first successful combination of optical trapping and FRET. By alternately exposing the sample molecule to the optical-trapping and fluorescence-excitation lasers, we demonstrate the ability to reversibly manipulate a single molecule while simultaneously monitoring its structural configuration. This integrated measurement provides high-resolution mechanical control over molecular conformation with fluorescence-based structural reporting. The application of this technique for single-molecule exploration will lead to new experiments that employ combined optical trapping and single-molecule fluorescence for the simultaneous and active manipulation and monitoring of molecular structure in real time.
Acta Biomaterialia, 2010
Actin filament (F-actin) is one of the dominant structural constituents in the cytoskeleton. Orch... more Actin filament (F-actin) is one of the dominant structural constituents in the cytoskeleton. Orchestrated by various actin binding proteins (ABPs), F-actin is assembled into higher-order structures such as bundles and networks that provide mechanical support for the cell and play important roles in numerous cellular processes. Although mechanical properties of F-actin networks have been extensively studied, the underlying mechanisms for network elasticity is not fully understood, in part because different measurements probe different length and force scales. Here, we developed both passive and active microrheology techniques using optical tweezers to estimate the mechanical properties of F-actin networks at a length scale comparable to cells. For the passive approach we tracked the motion of a thermally fluctuating colloidal sphere to estimate the frequencydependent complex shear modulus of the network. In the active approach, we used an optical trap to oscillate an embedded microsphere and monitored the response to obtain network viscoelasticity over a physiologically relevant force range. While both active and passive measurements exhibit similar results at low strain, the F-actin network subject to high strain exhibits non-linear behavior which is analogous to the strain-hardening observed in macroscale measurements. Using confocal and TIRF microscopy, we also characterize the microstructure of reconstituted F-actin networks in terms of filament length, mesh size, and degree of bundling. Finally, we propose a model of network connectivity by investigating the effect of filament length on the mechanical properties and structure.
ReVision, 2008
... states (brahmaviharas) or qualities of an enlightened per-sonthe other three being loving k... more ... states (brahmaviharas) or qualities of an enlightened per-sonthe other three being loving kindness (metta), compassion (karuna), and equanimity ... The discussion of the twin evolu-tionary origins of jealousy and monog-amy raises further questions: Can jeal-ousy be truly ...
Research Handbook on Climate Change Mitigation Law, 2015
SSRN Electronic Journal, 2000
SSRN Electronic Journal, 2000
ABSTRACT Despite the continuous efforts of developing countries and the international community t... more ABSTRACT Despite the continuous efforts of developing countries and the international community to reduce energy poverty, some 2.7 billion people around the world still rely on traditional biomass for cooking and heating and 1.3 billion people do not have access to electricity. Over 80% of the energy poor live in rural areas and roughly two thirds in sub-Saharan Africa and India. While fossil fuels will inevitably play a major role in expanding on-grid energy supply, this study shows that renewable energy sources – and especially small decentralized solutions – have huge potential for providing reliable, sustainable and affordable energy services for the poor, particularly in rural areas of developing countries. Many challenges remain, including financing, capacity-building, technology transfer and governance reforms. A careful assessment of the environmental impacts of renewable energy technologies, particularly those on water, is an important prerequisite for donor finance. With the right design, energy access projects can also bring a host of developmental co-benefits. It should be possible for international initiatives including the UN’s Year of Sustainable Energy for All and the EU’s partnership with Africa to build on the rich experience and lessons learned from pilot projects over the last two decades in order to optimize donor effectiveness in this area.
Intereconomics, 2012
Green growth is now a central theme of the international climate change negotiations. The Rio+20 ... more Green growth is now a central theme of the international climate change negotiations. The Rio+20 Conference in June will concentrate on green growth as one of its main priorities. The Europe 2020 strategy has identifi ed green growth as a fundamental pillar of EU economic policy. This Forum takes stock of the academic discussion and examines the theoretical and empirical underpinning of the concepts of green growth and employment through environmental policy.
ORL, 1991
Only a few studies have investigated vestibular function in diabetes mellitus (DM), showing contr... more Only a few studies have investigated vestibular function in diabetes mellitus (DM), showing contradictory results. We have performed an electronystagmographic (ENG) evaluation of 46 individuals with type I DM and 37 healthy controls. No patient reported subjective vestibular symptoms. Duration of caloric-induced nystagmus (DN) was significantly lower (2.1 +/- 0.7 vs. 2.6 +/- 0.4 min, p less than 0.01), and central nystagmus frequency of caloric response also nonsignificantly tended to be decreased (37.4 +/- 16.5 vs. 41.7 +/- 12.7 beats/30s, p = 0.21) in DM patients, as compared to controls. The latter comparison achieved significance after exclusion of newly diagnosed diabetic patients (33.4 +/- 16.1 vs. 41.6 +/- 12.7 beats/s, p less than 0.05). Depressed caloric reactions were seen in 21.8% of patients. DN was lower in patients with microalbuminuria and retinopathy, but this was not observed after exclusion of newly diagnosed diabetic patients, all of whom had normal ENG responses and no chronic diabetic complications. The existence of a lower DN and central nystagmus frequency should be borne in mind when interpreting ENG tracings in patients with long duration type I diabetes mellitus.
Methods in Molecular Biology, 2011
Noncoding regulatory genomic elements are central for cellular function, differentiation, and dis... more Noncoding regulatory genomic elements are central for cellular function, differentiation, and disease, but remain poorly characterized. FAIRE (formaldehyde-assisted isolation of regulatory elements) has emerged as a simple method to identify and analyze active regulatory sequences based on their decreased nucleosomal content. More recently FAIRE was combined with high-throughput sequencing (FAIRE-seq) to locate tissue-specific regulatory elements at a genome scale in purified human pancreatic islets. Here we describe the implementation of the FAIRE method in human pancreatic islet cells.
FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 2014
Fully differentiated pancreatic β cells are essential for normal glucose homeostasis in mammals. ... more Fully differentiated pancreatic β cells are essential for normal glucose homeostasis in mammals. Dedifferentiation of these cells has been suggested to occur in type 2 diabetes, impairing insulin production. Since chronic fuel excess ("glucotoxicity") is implicated in this process, we sought here to identify the potential roles in β-cell identity of the tumor suppressor liver kinase B1 (LKB1/STK11) and the downstream fuel-sensitive kinase, AMP-activated protein kinase (AMPK). Highly β-cell-restricted deletion of each kinase in mice, using an Ins1-controlled Cre, was therefore followed by physiological, morphometric, and massive parallel sequencing analysis. Loss of LKB1 strikingly (2.0-12-fold, E<0.01) increased the expression of subsets of hepatic (Alb, Iyd, Elovl2) and neuronal (Nptx2, Dlgap2, Cartpt, Pdyn) genes, enhancing glutamate signaling. These changes were partially recapitulated by the loss of AMPK, which also up-regulated β-cell "disallowed" genes (Slc16a1, Ldha, Mgst1, Pdgfra) 1.8- to 3.4-fold (E…
Journal of Medical Virology, 1995
Florida; the Guaymi from Panama; and the Toba, Chorote, Wichi, and Chulupe of Argentina, belonged... more Florida; the Guaymi from Panama; and the Toba, Chorote, Wichi, and Chulupe of Argentina, belonged to subtype B. The SKIIO/SKI 11 PCR-OR format should facilitate molecular epidemiology studies of HTLV-I1 infection and allow for subtype stratification in assessing the sensitivity and specificity of HTLV detection formats and HTLV-II disease association. o 1995 Wiley-Liss, tnc.
Virology, 2000
DNA was extracted from the peripheral blood of a seropositive, PCR-positive, BLV-infected Holstei... more DNA was extracted from the peripheral blood of a seropositive, PCR-positive, BLV-infected Holstein cow (No. 38) from Argentina. The DNA was amplified via PCR with a series of overlapping primers encompassing the entire BLV proviral DNA. The amplified BLV ARG 38 DNA was cloned, sequenced, and compared phylogenetically to three other full-length BLV sequences. Characterization of its deduced proteins and its relationship to other members of the PTLV/BLV genus of retroviruses are discussed.
American Journal of Veterinary Research, 2001
Cancer Investigation, 2002
A significant number of chronic lymphocytic leukemia, follicular non-Hodgkin&... more A significant number of chronic lymphocytic leukemia, follicular non-Hodgkin's lymphoma and Waldenström's macroglobulinemia patients, treated with fludarabine phosphate (fludarabine), are elderly with diminished renal function. Since the kidney eliminates approximately 60% of fludarabine's primary metabolite (F-ara-A), dose modification is necessary for all patients with impaired renal function including elderly patients. In this study, 22 patients with varying levels of renal function received a single intravenous dose of fludarabine (25 mg/m3), followed one week later by five (one per day) doses that were adjusted according to three predefined creatinine clearance (CLcr) levels. Relationships between renal function and F-ara-A clearance, F-ara-A exposure and F-ara-A--related toxicities were examined. The results demonstrate that total F-ara-A clearance correlated with CLcr and that F-ara-A exposure levels and patient toxicity profiles were similar across treatment groups. The CLcr-based fludarabine dose adjustments used in this study provided reasonably equivalent F-ara-A exposure with acceptable safety in patients with varying degrees of renal function.
Physical Review E, 2010
Lee, Hyungsuk et al. "Molecular origin of strain softening in cross-linked F-actin networks." Phy... more Lee, Hyungsuk et al. "Molecular origin of strain softening in cross-linked F-actin networks." Physical Review E 82.1 (2010): 011919.
Meat Science, 2008
This review deals with distinctive aspects of quality of Argentinean beef in terms of tenderness,... more This review deals with distinctive aspects of quality of Argentinean beef in terms of tenderness, flavour, colour, juiciness, taste, acceptability, lipid content and composition and its resultant nutraceutical characteristics. Differences are due to beef production systems based on temperate or tropical grasslands aimed at shortening the fattening phase as far as possible, with limited or null use of concentrates. However, the effect of limited supplemental feeding is also discussed as well as the responses arising from the use of beef cattle genotypes, including British, Continental, Dairy, Zebu breeds and their crosses, adapted to the various environments and systems found in the country.
Angewandte Chemie, 2007
Single-molecule techniques have been responsible for substantial advances in the field of biophys... more Single-molecule techniques have been responsible for substantial advances in the field of biophysics. Among these approaches, single-molecule fluorescence resonant energy transfer (FRET) spectroscopy provides an experimental view of the structural properties of individual molecules, whereas optical-tweezers force microscopy allows direct manipulation of the reaction coordinate of a single molecule. However, the simultaneous application of these techniques is complicated by optical-trap-induced photobleaching, which substantially reduces fluorophore longevity to unacceptably short timescales. Herein, we describe a general solution to this problem and apply it to a novel force sensor based on a DNA hairpin, in the first successful combination of optical trapping and FRET. By alternately exposing the sample molecule to the optical-trapping and fluorescence-excitation lasers, we demonstrate the ability to reversibly manipulate a single molecule while simultaneously monitoring its structural configuration. This integrated measurement provides high-resolution mechanical control over molecular conformation with fluorescence-based structural reporting. The application of this technique for single-molecule exploration will lead to new experiments that employ combined optical trapping and single-molecule fluorescence for the simultaneous and active manipulation and monitoring of molecular structure in real time.
Acta Biomaterialia, 2010
Actin filament (F-actin) is one of the dominant structural constituents in the cytoskeleton. Orch... more Actin filament (F-actin) is one of the dominant structural constituents in the cytoskeleton. Orchestrated by various actin binding proteins (ABPs), F-actin is assembled into higher-order structures such as bundles and networks that provide mechanical support for the cell and play important roles in numerous cellular processes. Although mechanical properties of F-actin networks have been extensively studied, the underlying mechanisms for network elasticity is not fully understood, in part because different measurements probe different length and force scales. Here, we developed both passive and active microrheology techniques using optical tweezers to estimate the mechanical properties of F-actin networks at a length scale comparable to cells. For the passive approach we tracked the motion of a thermally fluctuating colloidal sphere to estimate the frequencydependent complex shear modulus of the network. In the active approach, we used an optical trap to oscillate an embedded microsphere and monitored the response to obtain network viscoelasticity over a physiologically relevant force range. While both active and passive measurements exhibit similar results at low strain, the F-actin network subject to high strain exhibits non-linear behavior which is analogous to the strain-hardening observed in macroscale measurements. Using confocal and TIRF microscopy, we also characterize the microstructure of reconstituted F-actin networks in terms of filament length, mesh size, and degree of bundling. Finally, we propose a model of network connectivity by investigating the effect of filament length on the mechanical properties and structure.
ReVision, 2008
... states (brahmaviharas) or qualities of an enlightened per-sonthe other three being loving k... more ... states (brahmaviharas) or qualities of an enlightened per-sonthe other three being loving kindness (metta), compassion (karuna), and equanimity ... The discussion of the twin evolu-tionary origins of jealousy and monog-amy raises further questions: Can jeal-ousy be truly ...
Research Handbook on Climate Change Mitigation Law, 2015
SSRN Electronic Journal, 2000
SSRN Electronic Journal, 2000
ABSTRACT Despite the continuous efforts of developing countries and the international community t... more ABSTRACT Despite the continuous efforts of developing countries and the international community to reduce energy poverty, some 2.7 billion people around the world still rely on traditional biomass for cooking and heating and 1.3 billion people do not have access to electricity. Over 80% of the energy poor live in rural areas and roughly two thirds in sub-Saharan Africa and India. While fossil fuels will inevitably play a major role in expanding on-grid energy supply, this study shows that renewable energy sources – and especially small decentralized solutions – have huge potential for providing reliable, sustainable and affordable energy services for the poor, particularly in rural areas of developing countries. Many challenges remain, including financing, capacity-building, technology transfer and governance reforms. A careful assessment of the environmental impacts of renewable energy technologies, particularly those on water, is an important prerequisite for donor finance. With the right design, energy access projects can also bring a host of developmental co-benefits. It should be possible for international initiatives including the UN’s Year of Sustainable Energy for All and the EU’s partnership with Africa to build on the rich experience and lessons learned from pilot projects over the last two decades in order to optimize donor effectiveness in this area.
Intereconomics, 2012
Green growth is now a central theme of the international climate change negotiations. The Rio+20 ... more Green growth is now a central theme of the international climate change negotiations. The Rio+20 Conference in June will concentrate on green growth as one of its main priorities. The Europe 2020 strategy has identifi ed green growth as a fundamental pillar of EU economic policy. This Forum takes stock of the academic discussion and examines the theoretical and empirical underpinning of the concepts of green growth and employment through environmental policy.
ORL, 1991
Only a few studies have investigated vestibular function in diabetes mellitus (DM), showing contr... more Only a few studies have investigated vestibular function in diabetes mellitus (DM), showing contradictory results. We have performed an electronystagmographic (ENG) evaluation of 46 individuals with type I DM and 37 healthy controls. No patient reported subjective vestibular symptoms. Duration of caloric-induced nystagmus (DN) was significantly lower (2.1 +/- 0.7 vs. 2.6 +/- 0.4 min, p less than 0.01), and central nystagmus frequency of caloric response also nonsignificantly tended to be decreased (37.4 +/- 16.5 vs. 41.7 +/- 12.7 beats/30s, p = 0.21) in DM patients, as compared to controls. The latter comparison achieved significance after exclusion of newly diagnosed diabetic patients (33.4 +/- 16.1 vs. 41.6 +/- 12.7 beats/s, p less than 0.05). Depressed caloric reactions were seen in 21.8% of patients. DN was lower in patients with microalbuminuria and retinopathy, but this was not observed after exclusion of newly diagnosed diabetic patients, all of whom had normal ENG responses and no chronic diabetic complications. The existence of a lower DN and central nystagmus frequency should be borne in mind when interpreting ENG tracings in patients with long duration type I diabetes mellitus.
Methods in Molecular Biology, 2011
Noncoding regulatory genomic elements are central for cellular function, differentiation, and dis... more Noncoding regulatory genomic elements are central for cellular function, differentiation, and disease, but remain poorly characterized. FAIRE (formaldehyde-assisted isolation of regulatory elements) has emerged as a simple method to identify and analyze active regulatory sequences based on their decreased nucleosomal content. More recently FAIRE was combined with high-throughput sequencing (FAIRE-seq) to locate tissue-specific regulatory elements at a genome scale in purified human pancreatic islets. Here we describe the implementation of the FAIRE method in human pancreatic islet cells.
FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 2014
Fully differentiated pancreatic β cells are essential for normal glucose homeostasis in mammals. ... more Fully differentiated pancreatic β cells are essential for normal glucose homeostasis in mammals. Dedifferentiation of these cells has been suggested to occur in type 2 diabetes, impairing insulin production. Since chronic fuel excess ("glucotoxicity") is implicated in this process, we sought here to identify the potential roles in β-cell identity of the tumor suppressor liver kinase B1 (LKB1/STK11) and the downstream fuel-sensitive kinase, AMP-activated protein kinase (AMPK). Highly β-cell-restricted deletion of each kinase in mice, using an Ins1-controlled Cre, was therefore followed by physiological, morphometric, and massive parallel sequencing analysis. Loss of LKB1 strikingly (2.0-12-fold, E<0.01) increased the expression of subsets of hepatic (Alb, Iyd, Elovl2) and neuronal (Nptx2, Dlgap2, Cartpt, Pdyn) genes, enhancing glutamate signaling. These changes were partially recapitulated by the loss of AMPK, which also up-regulated β-cell "disallowed" genes (Slc16a1, Ldha, Mgst1, Pdgfra) 1.8- to 3.4-fold (E…