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Biomedical subjects

E Rojo

Publications and source records attributed to E Rojo.

14 recordsLinked to original sources
PubMed2001

Complications following repair of extrahepatic bile duct injuries after blunt abdominal trauma.

Extrahepatic bile duct traumatic injuries are extremely rare and their treatment is difficult and with several controversies. The aim of this study was to offer some more clinical information on their surgical repair and outcome. We present seven patients with extrahepatic biliary tract lesions after blunt abdominal trauma, (isolated gallbladder lesions were excluded) four males and three females from 23 to 51 years of age (mean age 35.1 years). All patients had suffered high-energy blunt abdominal trauma and presented associated injuries, mostly liver trauma and lung contusions. Six gallbladder lesions and six common bile duct injures were identified; a right hepatic duct laceration and a left hepatic duct transection were also present. Injuries were treated either with primary repair or with duct-jejunal anastomoses with Roux-en-Y reconstruction. Principal complications were postoperative anastomotic leakage (1 case) and recurrent cholangitis (3 cases) with or without stricture. Not-diagnosed injuries caused substantial morbidity. We prefer and recommend the use of primary repair in partial ruptures with no significant tissue loss and biliary-enteric anastomoses in large injuries and complete transections because they offer the best long-term drainage with less risk of stricture formation than end-to-end anastomoses. We defend the use of long duration (6 to 9 months) transanastomotic stents.

Abdominal Injuries↗
PubMed2001

Abdominal vascular injuries: injuries to the aorta.

This article discusses injuries to the abdominal aorta at its supra- and infrarenal positions, focusing on the surgical approaches to abdominal aorta injuries and renal vascular pedicles. The controversy regarding the use of bioprosthetic materials and the coLlective experience with these injuries as reported in the literature are reviewed. Primary renal artery repair versus nephrectomy also is examined.

Aorta, Abdominal↗
PubMed2001

Renal vascular injuries.

Even today, most renal vascular injuries result in loss of renal function. Kidney salvage is not possible because of late diagnosis and the presence of severe associated injuries. Physical exam and basic laboratory tests are not sensitive; thus, a high index of suspicion is required. Repair should be attempted for all solitary kidneys and for patients sustaining bilateral injuries. All viable kidneys should be revascularized in order to increase the chances of obtaining adequate functional renal tissue. In the event that revascularization is not feasible, nephrectomy can be performed at a later time, if hypertension develops. In some cases, delayed return of function is possible, but in most cases the kidney will atrophy without producing hypertension. Most importantly, maintaining a high index of suspicion, prompt diagnostic evaluation, and judicious treatment can optimize outcome lowering the significant morbidity and mortality of renal vascular injuries.

Humans↗
PubMed2001

VACUOLELESS1 is an essential gene required for vacuole formation and morphogenesis in Arabidopsis.

Most plant cells are characterized by the presence of a large central vacuole that in differentiated cells accounts for more than 90% of the total volume. We have undertaken a genetic screen to look for mutants that are affected in the formation of vacuoles in plants. In this study, we report that inactivation of the Arabidopsis gene VACUOLELESS1 (VCL1) blocks vacuole formation and alters the pattern of cell division orientation and cell elongation in the embryo. Consistent with a role in vacuole biogenesis, we show that VCL1 encodes the Arabidopsis ortholog of yeast Vps16p. In contrast to yeast mutants that lack a vacuolar compartment but are viable and morphologically normal, loss of the plant vacuole leads to aberrant morphogenesis and embryonic lethality.

Alleles↗
PubMed2001

Wound signalling in plants.

Plants undergoing the onslaught of wound-causing agents activate mechanisms directed to healing and further defence. Responses to mechanical damage are either local or systemic or both and hence involve the generation, translocation, perception, and transduction of wound signals to activate the expression of wound-inducible genes. Although the central role for jasmonic acid in plant responses to wounding is well established, other compounds, including the oligopeptide systemin, oligosaccharides, and other phytohormones such as abscisic acid and ethylene, as well as physical factors such as hydraulic pressure or electrical pulses, have also been proposed to play a role in wound signalling. Different jasmonic acid-dependent and -independent wound signal transduction pathways have been identified recently and partially characterized. Components of these signalling pathways are mostly similar to those implicated in other signalling cascades in eukaryotes, and include reversible protein phosphorylation steps, calcium/calmodulin-regulated events, and production of active oxygen species. Indeed, some of these components involved in transducing wound signals also function in signalling other plant defence responses, suggesting that cross-talk events may regulate temporal and spatial activation of different defences.

Arabidopsis↗
PubMed2000

The plant vacuolar sorting receptor AtELP is involved in transport of NH(2)-terminal propeptide-containing vacuolar proteins in Arabidopsis thaliana.

Many soluble plant vacuolar proteins are sorted away from secreted proteins into small vesicles at the trans-Golgi network by transmembrane cargo receptors. Cleavable vacuolar sorting signals include the NH(2)-terminal propeptide (NTPP) present in sweet potato sporamin (Spo) and the COOH-terminal propeptide (CTPP) present in barley lectin (BL). These two proteins have been found to be transported by different mechanisms to the vacuole. We examined the ability of the vacuolar cargo receptor AtELP to interact with the sorting signals of heterologous and endogenous plant vacuolar proteins in mediating vacuolar transport in Arabidopsis thaliana. AtELP extracted from microsomes was found to interact with the NTPPs of barley aleurain and Spo, but not with the CTPPs of BL or tobacco chitinase, in a pH-dependent and sequence-specific manner. In addition, EM studies revealed the colocalization of AtELP with NTPP-Spo at the Golgi apparatus, but not with BL-CTPP in roots of transgenic Arabidopsis plants. Further, we found that AtELP interacts in a similar manner with the NTPP of the endogenous vacuolar protein AtALEU (Arabidopsis thaliana Aleu), a protein highly homologous to barley aleurain. We hypothesize that AtELP functions as a vacuolar sorting receptor involved in the targeting of NTPP-, but not CTPP-containing proteins in Arabidopsis.

Arabidopsis↗
PubMed2000

European Society of Gene Therapy (ESGT) Seventh Meeting. 26-28 November 1999, Munich, Germany.

This meeting gave an excellent overview of the recent developments in gene therapy. Much research effort has focused on the improvement and de novo construction of gene vectors, on characterizing their mechanisms of action and on their interactions with, and in, living organisms. The continual improvements in understanding disease at a molecular level and the progress in cell biology, immunology and related fields have opened the way for novel gene therapy approaches. The gene therapeutic strategy has proven to be feasible and efficient in numerous preclinical (animal) models of a variety of diseases. On the other hand, applying this experience to humans has turned out to be difficult. Currently, the field is rapidly moving into clinical applications. No major limiting side effects have been observed in patients in the phase I and later stage trials presented. Nonetheless, years of preclinical and clinical research will be required before gene therapy can be considered a reliable and efficient therapeutic approach with broad applicability.

Journal Article↗
PubMed1999

Cross-talk between wound signalling pathways determines local versus systemic gene expression in Arabidopsis thaliana.

Plants react to mechanical damage by activating a set of genes, the products of which are thought to serve defensive functions. In solanaceous plants, cell wall-derived oligosaccharides and the plant hormones jasmonic acid and ethylene participate in the signalling network for wound-induced expression of proteinase inhibitors and other defence-related genes, both in the locally damaged and in the systemic non-damaged leaves. Here we show that in Arabidopsis thaliana, these signalling components interact in novel ways to activate distinct responses. In damaged tissues, oligosaccharides induce the expression of a specific set of wound-responsive genes while repressing jasmonic acid-responsive genes that are activated in the systemic tissues. The oligosaccharide-mediated repression of the jasmonic acid-dependent signalling pathway is exerted through the production and perception of ethylene in the locally damaged tissue. This cross-talk between separate wound signalling pathways thus allows the set up of different responses in the damaged and the systemic tissues of plants reacting to injury.

Journal Article↗
PubMed1998

Jasmonic acid-dependent and -independent wound signal transduction pathways are differentially regulated by Ca2+/calmodulin in Arabidopsis thaliana.

We have used wound- and jasmonic acid (JA)-responsive genes as molecular markers to elucidate the pathway(s) of wound signal transduction in Arabidopsis thaliana. The JA-responsive (JR) genes JR1, JR2, and JR3 are strongly induced by wounding and by JA, while the wound-responsive (WR) genes WR3 and acyl CoA oxidase (ACO) are induced by wounding only. Accumulation of JR transcripts upon wounding was blocked by indomethacin. However, indomethacin did not affect either induction of these genes by JA or wound-induced expression of WR genes, suggesting that JA synthesis is only needed for wound-dependent induction of JR genes, and also that separate JA-dependent and -independent wound signal transduction pathways exist in Arabidopsis. The two pathways are differentially regulated by Ca2+ and calmodulin. Mobilization of intracellular Ca2+ pools blocked induction of JR genes by both wounding and JA, but not the induction of WR genes by wounding, but this effect could not be reproduced by increasing intracellular Ca2+ levels using ionophores. In addition, calmodulin antagonists blocked the expression of JR genes and up-regulated WR gene expression. Ca2+ and calmodulin seem to act downstream of both JA and the COI1 gene in the JA-dependent pathway, and downstream of reversible phosphorylation events that differentially regulate JA-dependent and JA-independent wound signal transduction pathways.

Arabidopsis↗
PubMed1998

Reversible protein phosphorylation regulates jasmonic acid-dependent and -independent wound signal transduction pathways in Arabidopsis thaliana.

Plants responses to mechanical injury are complex and include the induced expression of defence-related genes. The phytohormone JA has been reported to mediate some of these responses. To elucidate further the signal transduction processes involved, the action of specific agonists and antagonists of known signalling effectors on the response of Arabidopsis thaliana plantlets to JA and wounding was investigated. The identification and characterization of a reversible protein phosphorylation step in a transduction pathway leading to JA-induced gene transcription is reported. This phosphorylation event involved the opposing activities of a staurosporine-sensitive protein kinase, negatively regulating the pathway, and a protein phosphatase, most probably of type 2 A, which activated JA-responsive gene expression. JA activation via this pathway was blocked in the A. thaliana JA-insensitive mutants jin1, jin4 and coi1, and by exogenous application of cycloheximide or auxins. Wound-induced activation of JA-responsive genes was also regulated by this protein phosphorylation step. An alternative wound signalling pathway, independent of JA, was also identified, leading to the transcriptional activation of a different set of genes. This JA-independent pathway was also regulated by a protein phosphorylation switch, in which the protein kinase positively regulated the pathway while the protein phosphatase negatively regulated it. Moreover, a labile protein apparently repressed the expression of these genes. One of the genes analysed, JR3, had a complex pattern of expression, possibly because it was regulated via both of the wound signalling pathways identified. According to the function of an homologous gene, JR3 may be involved in feedback inhibition of the JA response.

Arabidopsis↗
PubMed1997

Abscisic acid and jasmonic acid activate wound-inducible genes in potato through separate, organ-specific signal transduction pathways.

Mechanical damage to leaf tissue causes an increase in abscisic acid (ABA) which in turn activates the biosynthesis of jasmonic acid (JA). The resulting higher endogenous JA levels subsequently activate the expression of wound-inducible genes. This study shows that JA induces the expression of different sets of genes in roots and leaves of potato plants. When roots of intact plants were treated with JA, high levels of proteinase inhibitor II (pin2), cathepsin D inhibitor, leucine aminopeptidase and threonine deaminase mRNAs accumulated in the systemic leaves. However, in the treated roots, very low, if any, expression of these genes could be detected. In contrast, a novel, root-specific pin2 homologue accumulated in the JA-treated root tissue which could not be detected in leaves, either systemic or those directly treated with JA. Application of okadaic acid and staurosporine revealed that a protein phosphorylation step is involved in the regulation of this differential response. In leaves, a protein phosphatase is required for the JA-induced expression of pin2 and the other genes analysed. This phosphatase activity is not necessary for the JA-induced expression of a pin2 homologue in roots, suggesting the existence of different transduction pathways for the JA signal in these organs. The requirement of a protein phosphatase activity for JA-mediated gene induction has enabled identification of a JA-independent pathway for ABA induction of pin2 and the other wound-inducible genes. This alternative pathway involves a protein kinase, and appears to be selective for wound-inducible genes. Our data suggest the presence of a complex, organ-specific transduction network for regulating the effects of the plant hormones ABA and JA on gene expression upon wounding.

Abscisic Acid↗
PubMed1997

Jasmonic acid-dependent and -independent signaling pathways control wound-induced gene activation in Arabidopsis thaliana.

Plant response to mechanical injury includes gene activation both at the wound site and systemically in nondamaged tissues. The model developed for the wound-induced activation of the proteinase inhibitor II (Pin2) gene in potato (Solanum tuberosum) and tomato (Lycopersicon esculentum) establishes the involvement of the plant hormones abscisic acid and jasmonic acid (JA) as key components of the wound signal transduction pathway. To assess in Arabidopsis thaliana the role of these plant hormones in regulating wound-induced gene expression, we isolated wound- and JA-inducible genes by the differential mRNA display technique. Their patterns of expression upon mechanical wounding and hormonal treatments revealed differences in the spatial distribution of the transcripts and in the responsiveness of the analyzed genes to abscisic acid and JA. A correlation can be established between sensitivity to JA and the accumulation of the transcripts in systemic tissues upon wounding. A comparative study of the wound response in wild-type and JA-insensitive coi1 mutant plants indicated that in A. thaliana wound signals are transmitted via at least two different pathways. One of them does not involve JA as a mediator and is preferentially responsible for gene activation in the vicinity of the wound site, whereas the other requires JA perception and activates gene expression throughout the aerial part of the plant.

Arabidopsis↗
PubMed1987

Epidemic outbreak of Serratia marcescens infection in a cardiac surgery unit.

Between 2 February and 16 April 1985, an outbreak of Serratia marcescens infection involving 10 male patients occurred in a cardiac surgery unit. All the patients had surgical wound infection, five also had osteomyelitis (four sternal, one costal), and another had peritonitis secondary to peritoneal dialysis. Three patients had concomitant bacteremia. All Serratia strains isolated produced a cherry-red pigment, and all had the same biochemical and antibiotic susceptibility pattern. An intensive search for the origin of the outbreak was initially unsuccessful, and it proved impossible to isolate S. marcescens from cultures of numerous samples taken from hospital personnel and from the environment. The fact that all patients were male and had been shaved for surgery by the same team of barbers led us to investigate the shaving procedures. We finally isolated a strain of pigmented S. marcescens, corresponding to that involved in the outbreak, from samples taken from the hands and equipment of the barbers. After suitable action had been taken, the epidemic terminated.

Barbering↗