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Cristian Perez

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John Glendinning

Robert Margolskee

Goran Hellekant

University of Minnesota

Jared Schmolling

University of Minnesota, Duluth

Teresa Rose-hellekant

Inigo Verdaletguzman

Universidad Veracruzana

University of Alberta

Homero Rios-figueroa

Universidad Veracruzana

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Papers by Cristian Perez

Trpm5 Null Mice Respond to Bitter, Sweet, and Umami Compounds

Trpm5 is a calcium-activated cation channel expressed selectively in taste receptor cells. A prev... more Trpm5 is a calcium-activated cation channel expressed selectively in taste receptor cells. A previous study reported that mice with an internal deletion of Trpm5, lacking exons 15-19 encoding transmembrane segments 1-5, showed no taste-mediated responses to bitter, sweet, and umami compounds. We independently generated knockout mice null for Trpm5 protein expression due to deletion of Trpm5#s promoter region and exons 1-4 (including the translation start site). We examined the tastemediated responses of Trpm5 null mice and wild-type (WT) mice using three procedures: gustatory nerve recording [chorda tympani (CT) and glossopharyngeal (NG) nerves], initial lick responses, and 24-h two-bottle preference tests. With bitter compounds, the Trpm5 null mice showed reduced, but not abolished, avoidance (as indicated by licking responses and preference ratios higher than those of WT), a normal CT response, and a greatly diminished NG response. With sweet compounds, Trpm5 null mice showed no licking response, a diminished preference ratio, and absent or greatly reduced nerve responses. With umami compounds, Trpm5 null mice showed no licking response, a diminished preference ratio, a normal NG response, and a greatly diminished CT response. Our results demonstrate that the consequences of eliminating Trmp5 expression vary depending upon the taste quality and the lingual taste field examined. Thus, while Trpm5 is an important factor in many taste responses, its absence does not eliminate all taste responses. We conclude that Trpm5-dependent and Trpm5-independent pathways underlie bitter, sweet, and umami tastes.

DÍGAME: A Vision of an Active Multidatabase with Push-based Schema and Data Propagation

Sharing information in loosely coupled enterprises or virtual corporations demands a flexible and... more Sharing information in loosely coupled enterprises or virtual corporations demands a flexible and dynamic architecture, suitable for their individual data policies. The aim of this paper is to present the Dígame architecture, which balances both, local autonomy and a reasonable degree of information sharing. Therefore we combine the well known concept of loosely coupled multidatabases with more recent research in Peer-to-Peer or grid computing, satisfying the needs of modern intraand inter-enterprise collaboration. In our architecture data and schema updates are propagated actively to subscribing component databases, without being managed by any central authority. This replication gives us the possibility to realize individual integration on each single peer.

Acetylcholinesterase Accelerates Assembly of Amyloid-β-Peptides into Alzheimer's Fibrils: Possible Role of the Peripheral Site of the Enzyme

Neuron, 1996

Acetylcholinesterase (AChE), an important component of cholinergic synapses, colocalizes with amy... more Acetylcholinesterase (AChE), an important component of cholinergic synapses, colocalizes with amyloid-β peptide (Aβ) deposits of Alzheimer's brain. We report here that bovine brain AChE, as well as the human and mouse recombinant enzyme, accelerates amyloid formation from wild-type Aβ and a mutant Aβ peptide, which alone produces few amyloid-like fibrils. The action of AChE was independent of the subunit array of the enzyme, was not affected by edrophonium, an active site inhibitor, but it was affected by propidium, a peripheral anionic binding site ligand. Butyrylcholinesterase, an enzyme that lacks the peripheral site, did not affect amyloid formation. Furthermore, AChE is a potent amyloid-promoting factor when compared with other Aβ-associated proteins. Thus, in addition to its role in cholinergic synapses, AChE may function by accelerating Aβ formation and could play a role during amyloid deposition in Alzheimer's brain.

Acetylcholinesterase, a senile plaque component, affects the fibrillogenesis of amyloid-β-peptides

Neuroscience Letters, 1995

(AChE) colocalizes with amyloid$ peptide (@) deposits present in the brain of Alzheimer's patient... more (AChE) colocalizes with amyloid$ peptide (@) deposits present in the brain of Alzheimer's patients. Recent studies showed that Ml-40 can adopt two different conformational states in solution (an amyloidogenic conformer, A/3 ac, and a nonamyloidogenic conformer, A#I nac) which have distinct abilities to form amyloid fibrils. We report here that AChE binds A/I nut and accelerates amyloid formation by the same peptide. NO such effect was observed with Aj3 ac, the amyloidogenic conformer, suggesting that AChE acts as a 'pathological chaperone' inducing a conformational transition from @ nac into AB uc in vitro.

Relational.OWL - A Data and Schema Representation Format Based on OWL

One of the research fields which has recently gained much scientific interest within the database... more One of the research fields which has recently gained much scientific interest within the database community are Peer-to-Peer databases, where peers have the autonomy to decide whether to join or to leave an information sharing environment at any time. Such volatile data nodes may appear shortly, collect or deliver some data, and disappear again. It even can not be assured that a peer joins the network ever again. In this paper we introduce a representation format fort both, schema and data information based on the Web Ontology Language OWL. According to the advantages of the Semantic Web we are thus able to represent and to transfer every schema and data component of a database to any partner, without having to define a data and schema exchange format explicitly.

Bringing Relational Data into the SemanticWeb using SPARQL and Relational.OWL

... query contains objects, which are simultaneously of the db:ADDRESS and the db:COUNTRY type. .... more

A transient receptor potential channel expressed in taste receptor cells

Nature Neuroscience, 2002

A Semantic Web based Identification Mechanism for Databases

In this paper we suggest the novel URI scheme db for identifying not only databases, but also the... more In this paper we suggest the novel URI scheme db for identifying not only databases, but also their schema and data components like tables or columns. One of the features of this scheme is that it may not only be used for relational database systems, but for virtually any type of database or data source. We therefore have combined the advantages of both global uniqueness of URIs and the high flexibility of knowledge representation with RDF as part of the Semantic Web. With this novel identifier we are now able to enhance every data record exchanged between databases with metadata: an exact and identifying location of that data in the data source. As a result not only the system administrator is able to backtrack the data to its exact position in the data source but also the database system itself.

PHYLOGENETIC RELATIONSHIPS OF LIZARDS OF THE LIOLAEMUS PETROPHILUS GROUP (SQUAMATA, LIOLAEMIDAE), WITH DESCRIPTION OF TWO NEW SPECIES FROM WESTERN ARGENTINA

Herpetologica, 2004

We describe two new species of lizards of the genus Liolaemus from western Argentina. Both specie... more We describe two new species of lizards of the genus Liolaemus from western Argentina. Both species belong to the petrophilus group and are easily distinguished from other members by a combination of chromatic and squamation characters. We used sequences of the mitochondrial cyt-b, 12S, and ND4 and the nuclear C-mos genes to infer the phylogeny of described species of the group. We found evidence for a monophyletic petrophilus group within the L. elongatus-kriegi complex. The petrophilus group includes Liolaemus petrophilus and two strongly supported clades, one containing the species distributed in the north, which includes one of the new species, L. talampaya; the second clade includes the species distributed in the south, including the new species, L. gununakuna.

Prevalence and characteristics of smoking in primary healthcare workers in Iquique, Chile

Public Health, 2006

Objective: To determine the prevalence and characteristics of the smoking habits of primary healt... more

Detection of Apolipoprotein E/Dimeric Soluble Amyloid β Complexes in Alzheimer's Disease Brain Supernatants

Biochemical and Biophysical Research Communications, 1997

The inheritance of the apolipoprotein (apo) E4 allele is an important risk factor for late-onset ... more The inheritance of the apolipoprotein (apo) E4 allele is an important risk factor for late-onset Alzheimer&#39;s disease (AD). A major component of the Alzheimer&#39;s disease neuritic plaques is amyloid beta (A beta). We previously identified apoE/A beta complexes within neuritic plaques (1). It was not known if this interaction takes place before or after A beta peptides become incorporated into neuritic plaques. To address this question we sought evidence of apoE complexes with brain soluble A beta peptides in AD and control patients. In addition, numerous proteins have been shown to bind A beta peptides in vitro. It is not know if any of these bind brain sA beta in vivo. We found evidence for the presence of apoE/dimeric sA beta complexes in the AD brain and could not detect complexes with other A beta peptide binding proteins. The binding of sA beta to apoE may be one factor influencing its clearance from the brain and/or its conformational state.

Detection of Apolipoprotein E/Dimeric Soluble Amyloid β Complexes in Alzheimer's Disease Brain Supernatants

Biochemical and Biophysical Research Communications, 1997

The inheritance of the apolipoprotein (apo) E4 allele is an important risk factor for late-onset ... more The inheritance of the apolipoprotein (apo) E4 allele is an important risk factor for late-onset Alzheimer&#39;s disease (AD). A major component of the Alzheimer&#39;s disease neuritic plaques is amyloid beta (A beta). We previously identified apoE/A beta complexes within neuritic plaques (1). It was not known if this interaction takes place before or after A beta peptides become incorporated into neuritic plaques. To address this question we sought evidence of apoE complexes with brain soluble A beta peptides in AD and control patients. In addition, numerous proteins have been shown to bind A beta peptides in vitro. It is not know if any of these bind brain sA beta in vivo. We found evidence for the presence of apoE/dimeric sA beta complexes in the AD brain and could not detect complexes with other A beta peptide binding proteins. The binding of sA beta to apoE may be one factor influencing its clearance from the brain and/or its conformational state.

Simplified analytic study of the HBC fuse ability to withstand induction motor start cycles

One of the main causes of unexpected and incorrect operation of the high breaking capacity medium... more One of the main causes of unexpected and incorrect operation of the high breaking capacity medium voltage fuses protecting induction motors is the aging originated in the start cycles. Up to now the main source of information to keep in mind the start cycle consists in graphic or charts given by the fuse makers for a reduced number of start

Trpm5 Null Mice Respond to Bitter, Sweet, and Umami Compounds

Trpm5 is a calcium-activated cation channel expressed selectively in taste receptor cells. A prev... more Trpm5 is a calcium-activated cation channel expressed selectively in taste receptor cells. A previous study reported that mice with an internal deletion of Trpm5, lacking exons 15-19 encoding transmembrane segments 1-5, showed no taste-mediated responses to bitter, sweet, and umami compounds. We independently generated knockout mice null for Trpm5 protein expression due to deletion of Trpm5#s promoter region and exons 1-4 (including the translation start site). We examined the tastemediated responses of Trpm5 null mice and wild-type (WT) mice using three procedures: gustatory nerve recording [chorda tympani (CT) and glossopharyngeal (NG) nerves], initial lick responses, and 24-h two-bottle preference tests. With bitter compounds, the Trpm5 null mice showed reduced, but not abolished, avoidance (as indicated by licking responses and preference ratios higher than those of WT), a normal CT response, and a greatly diminished NG response. With sweet compounds, Trpm5 null mice showed no licking response, a diminished preference ratio, and absent or greatly reduced nerve responses. With umami compounds, Trpm5 null mice showed no licking response, a diminished preference ratio, a normal NG response, and a greatly diminished CT response. Our results demonstrate that the consequences of eliminating Trmp5 expression vary depending upon the taste quality and the lingual taste field examined. Thus, while Trpm5 is an important factor in many taste responses, its absence does not eliminate all taste responses. We conclude that Trpm5-dependent and Trpm5-independent pathways underlie bitter, sweet, and umami tastes.

DÍGAME: A Vision of an Active Multidatabase with Push-based Schema and Data Propagation

Sharing information in loosely coupled enterprises or virtual corporations demands a flexible and... more Sharing information in loosely coupled enterprises or virtual corporations demands a flexible and dynamic architecture, suitable for their individual data policies. The aim of this paper is to present the Dígame architecture, which balances both, local autonomy and a reasonable degree of information sharing. Therefore we combine the well known concept of loosely coupled multidatabases with more recent research in Peer-to-Peer or grid computing, satisfying the needs of modern intraand inter-enterprise collaboration. In our architecture data and schema updates are propagated actively to subscribing component databases, without being managed by any central authority. This replication gives us the possibility to realize individual integration on each single peer.

Acetylcholinesterase Accelerates Assembly of Amyloid-β-Peptides into Alzheimer's Fibrils: Possible Role of the Peripheral Site of the Enzyme

Neuron, 1996

Acetylcholinesterase (AChE), an important component of cholinergic synapses, colocalizes with amy... more Acetylcholinesterase (AChE), an important component of cholinergic synapses, colocalizes with amyloid-β peptide (Aβ) deposits of Alzheimer's brain. We report here that bovine brain AChE, as well as the human and mouse recombinant enzyme, accelerates amyloid formation from wild-type Aβ and a mutant Aβ peptide, which alone produces few amyloid-like fibrils. The action of AChE was independent of the subunit array of the enzyme, was not affected by edrophonium, an active site inhibitor, but it was affected by propidium, a peripheral anionic binding site ligand. Butyrylcholinesterase, an enzyme that lacks the peripheral site, did not affect amyloid formation. Furthermore, AChE is a potent amyloid-promoting factor when compared with other Aβ-associated proteins. Thus, in addition to its role in cholinergic synapses, AChE may function by accelerating Aβ formation and could play a role during amyloid deposition in Alzheimer's brain.

Acetylcholinesterase, a senile plaque component, affects the fibrillogenesis of amyloid-β-peptides

Neuroscience Letters, 1995

(AChE) colocalizes with amyloid$ peptide (@) deposits present in the brain of Alzheimer's patient... more (AChE) colocalizes with amyloid$ peptide (@) deposits present in the brain of Alzheimer's patients. Recent studies showed that Ml-40 can adopt two different conformational states in solution (an amyloidogenic conformer, A/3 ac, and a nonamyloidogenic conformer, A#I nac) which have distinct abilities to form amyloid fibrils. We report here that AChE binds A/I nut and accelerates amyloid formation by the same peptide. NO such effect was observed with Aj3 ac, the amyloidogenic conformer, suggesting that AChE acts as a 'pathological chaperone' inducing a conformational transition from @ nac into AB uc in vitro.

Relational.OWL - A Data and Schema Representation Format Based on OWL

One of the research fields which has recently gained much scientific interest within the database... more One of the research fields which has recently gained much scientific interest within the database community are Peer-to-Peer databases, where peers have the autonomy to decide whether to join or to leave an information sharing environment at any time. Such volatile data nodes may appear shortly, collect or deliver some data, and disappear again. It even can not be assured that a peer joins the network ever again. In this paper we introduce a representation format fort both, schema and data information based on the Web Ontology Language OWL. According to the advantages of the Semantic Web we are thus able to represent and to transfer every schema and data component of a database to any partner, without having to define a data and schema exchange format explicitly.

Bringing Relational Data into the SemanticWeb using SPARQL and Relational.OWL

... query contains objects, which are simultaneously of the db:ADDRESS and the db:COUNTRY type. .... more

A transient receptor potential channel expressed in taste receptor cells

Nature Neuroscience, 2002

A Semantic Web based Identification Mechanism for Databases

In this paper we suggest the novel URI scheme db for identifying not only databases, but also the... more In this paper we suggest the novel URI scheme db for identifying not only databases, but also their schema and data components like tables or columns. One of the features of this scheme is that it may not only be used for relational database systems, but for virtually any type of database or data source. We therefore have combined the advantages of both global uniqueness of URIs and the high flexibility of knowledge representation with RDF as part of the Semantic Web. With this novel identifier we are now able to enhance every data record exchanged between databases with metadata: an exact and identifying location of that data in the data source. As a result not only the system administrator is able to backtrack the data to its exact position in the data source but also the database system itself.

PHYLOGENETIC RELATIONSHIPS OF LIZARDS OF THE LIOLAEMUS PETROPHILUS GROUP (SQUAMATA, LIOLAEMIDAE), WITH DESCRIPTION OF TWO NEW SPECIES FROM WESTERN ARGENTINA

Herpetologica, 2004

We describe two new species of lizards of the genus Liolaemus from western Argentina. Both specie... more We describe two new species of lizards of the genus Liolaemus from western Argentina. Both species belong to the petrophilus group and are easily distinguished from other members by a combination of chromatic and squamation characters. We used sequences of the mitochondrial cyt-b, 12S, and ND4 and the nuclear C-mos genes to infer the phylogeny of described species of the group. We found evidence for a monophyletic petrophilus group within the L. elongatus-kriegi complex. The petrophilus group includes Liolaemus petrophilus and two strongly supported clades, one containing the species distributed in the north, which includes one of the new species, L. talampaya; the second clade includes the species distributed in the south, including the new species, L. gununakuna.

Prevalence and characteristics of smoking in primary healthcare workers in Iquique, Chile

Public Health, 2006

Objective: To determine the prevalence and characteristics of the smoking habits of primary healt... more

Detection of Apolipoprotein E/Dimeric Soluble Amyloid β Complexes in Alzheimer's Disease Brain Supernatants

Biochemical and Biophysical Research Communications, 1997

The inheritance of the apolipoprotein (apo) E4 allele is an important risk factor for late-onset ... more The inheritance of the apolipoprotein (apo) E4 allele is an important risk factor for late-onset Alzheimer&#39;s disease (AD). A major component of the Alzheimer&#39;s disease neuritic plaques is amyloid beta (A beta). We previously identified apoE/A beta complexes within neuritic plaques (1). It was not known if this interaction takes place before or after A beta peptides become incorporated into neuritic plaques. To address this question we sought evidence of apoE complexes with brain soluble A beta peptides in AD and control patients. In addition, numerous proteins have been shown to bind A beta peptides in vitro. It is not know if any of these bind brain sA beta in vivo. We found evidence for the presence of apoE/dimeric sA beta complexes in the AD brain and could not detect complexes with other A beta peptide binding proteins. The binding of sA beta to apoE may be one factor influencing its clearance from the brain and/or its conformational state.

Detection of Apolipoprotein E/Dimeric Soluble Amyloid β Complexes in Alzheimer's Disease Brain Supernatants

Biochemical and Biophysical Research Communications, 1997

The inheritance of the apolipoprotein (apo) E4 allele is an important risk factor for late-onset ... more The inheritance of the apolipoprotein (apo) E4 allele is an important risk factor for late-onset Alzheimer&#39;s disease (AD). A major component of the Alzheimer&#39;s disease neuritic plaques is amyloid beta (A beta). We previously identified apoE/A beta complexes within neuritic plaques (1). It was not known if this interaction takes place before or after A beta peptides become incorporated into neuritic plaques. To address this question we sought evidence of apoE complexes with brain soluble A beta peptides in AD and control patients. In addition, numerous proteins have been shown to bind A beta peptides in vitro. It is not know if any of these bind brain sA beta in vivo. We found evidence for the presence of apoE/dimeric sA beta complexes in the AD brain and could not detect complexes with other A beta peptide binding proteins. The binding of sA beta to apoE may be one factor influencing its clearance from the brain and/or its conformational state.

Simplified analytic study of the HBC fuse ability to withstand induction motor start cycles

One of the main causes of unexpected and incorrect operation of the high breaking capacity medium... more One of the main causes of unexpected and incorrect operation of the high breaking capacity medium voltage fuses protecting induction motors is the aging originated in the start cycles. Up to now the main source of information to keep in mind the start cycle consists in graphic or charts given by the fuse makers for a reduced number of start