Reduced salivary gland size and increased presence of epithelial progenitor cells in DLK1-deficient mice.

DLK1 (PREF1, pG2, or FA1) is a transmembrane and secreted protein containing epidermal growth factor-like repeats. Dlk1 expression is abundant in many tissues during embryonic and fetal development and is believed to play an important role in the regulation of tissue differentiation and fetal growth. After birth, Dlk1 expression is abolished in most tissues but is possibly reactivated to regulate stem cell activation and responses to injury. We have recently reported that DLK1 regulates many aspects of salivary gland organogenesis. Here, we have extended our studies of the salivary gland phenotype of Dlk1 knock-out mice. We have observed that salivary glands are smaller and weigh significantly less in both Dlk1 knock-out males and females compared with gender and age-matched wild-type mice and regardless of the natural sexual dimorphism in rodent salivary glands. This reduced size correlates with a reduced capacity of Dlk1-deficient mice to secrete saliva after stimulation with pilocarpine. However, histological and ultrastructural analyses of both adult and developing salivary gland tissues have revealed no defects in Dlk1 ((-/-)) mice, indicating that genetic compensation accounts for the relatively mild salivary phenotype in these animals. Finally, despite their lack of severe anomalies, we have found that salivary glands from Dlk1-deficient mice present a higher amount of CK14-positive epithelial progenitors at various developmental stages, suggesting a role for DLK1 in the regulation of salivary epithelial stem cell balance.

[Development of animal experimental model for bacterial peritonitis]. / Desarrollo de modelo experimental animal de peritonitis bacteriana.

OBJECTIVE: The aim of the study was to develop a model of abdominal sepsis in the experimental animal. METHODS: Sprague-Dawley male rats of 5 weeks (N=39) were used. Initially, a pilot study (N = 9) was performed and distributed in 3 groups with 1cc inoculum of Escherichia coli ATCC 25922 intraperitoneally at concentrations of 10E8, 10E9 and 10E10 CFU. Subsequently, concentrations of 10E10 CFU are used in two groups of 3 rats with dilutions of 10 cc and 15 cc of distilled water respectively. Finally, a randomized trial of 24 rats was started in three treatment groups after intraperitoneal infection: Group I with physiological serum (N = 6), Group II with ceftriaxone (N = 9), Group III with ceftriaxone plus allicin (N = 9). Microbiological samples of blood and peritoneal fluid were made, as well as histopathological study of intraperitoneal organs (liver, diaphragm and peritoneum). RESULTS: Death of 100% of the rats infected with 10E10 E. coli UFC concentration with the dilution of 15 ml of distilled water and without antibiotic was oberved. The blood culture and peritoneal fluid culture was positive for the same strain in all of them. The formation of abscesses on the liver surface and polymorphonuclear infiltration in tissues were observed. CONCLUSIONS: The lethal dose of E. coli is 10E10 CFU diluted in 15 cc distilled water by intraperitoneal injection.

Laparoscopic cytoreductive surgery and HIPEC is effective regarding peritoneum tissue paclitaxel distribution.

BACKGROUND: In some patients with peritoneal carcinomatosis, we could perform the cytoreductive surgery and the HIPEC procedure by a complete laparoscopic approach to avoid morbidity. We consider that using laparoscopic approach for performing peritoneal carcinomatosis cytoreductive surgery and HIPEC with closed CO2 recirculation technique is possible and safe, with equal efficacy to conventional methods and hemodynamic complications. OBJECTIVE: Monitoring the effectiveness of the drug distribution in a laparoscopic ctoreductive and HIPEC surgery group with CO2 recirculation respect to a closed and open HIPEC group METHODS: Porcine model that included fifteen mini-pigs. Five pigs were operated with laparoscopic approach performing a pelvic and retroperitoneal lymphadenectomy. They later received a total laparoscopic closed HIPEC with CO2 recirculation (G1). Group 2 (G2): five pigs operated by an open cytoreductive surgery and closed HIPEC technique. Group 3 (G3): five animals in which an open cytoreductive surgery and an open HIPEC technique was performed. Blood and peritoneal determinations were realized after recirculation of the drug, at 60 min using chromatographic analysis. RESULTS: G1-G2: phrenic right peritoneum, p: 0.46. Phrenic left peritoneum, p: 0.46. Pelvic peritoneum, p: 0.17. Serum paclitaxel: p: 0.01. G1-G3: phrenic right peritoneum, p: 0.34. Phrenic left peritoneum, p: 0.34. Pelvic peritoneum, p: 0.17. Serum paclitaxel G1-G3, p: 0.02. CONCLUSIONS: A total laparoscopic approach for ctoreductive surgery and closed HIPEC with CO2 recirculation may be safe and feasible. In our experimental model there was no significant difference in tissue drug distribution respect the conventional techniques and there was a less toxicity because the serum drug concentration was significantly lower with laparoscopic approach respect the other groups.

Specific regions of the extracellular domain of dlk, an EGF-like homeotic protein involved in differentiation, participate in intramolecular interactions.

The level of expression of dlk, an EGF-like protein possessing six EGF-like repeats in its extracellular region, is critical for 3T3-L1 fibroblasts to differentiate into adipocytes in response to IGF1. The mechanism of action of dlk is not well understood, but its localization on the cell membrane suggests that dlk may function as a receptor, as a ligand or as a regulatory protein modulating the binding, the signaling, or the expression of other molecules involved in cell differentiation and growth. In this work, we demonstrate, by using the Yeast Two-Hybrid system, that dlk interacts with itself through specific regions of its extracellular domain. The strongest interactions were observed between specific EGF-like repeats and between a non EFG-like region where unknown proteases act to generate soluble forms of dlk. These observations suggest that the interaction between two membrane dlk molecules belonging to the same or to different cells, or the interaction between soluble and membrane dlk variants, may be important to regulate dlk function.

The complete sequence of a 15,820 bp segment of Saccharomyces cerevisiae chromosome XI contains the UBI2 and MPL1 genes and three new open reading frames.

As part of the EEC yeast genome program, a fragment of 15,820 bp from the right arm of Saccharomyces cerevisiae chromosome XI has been sequenced. This fragment corresponds roughly to the centromere-distal half of cosmid pUKG046 and to a small fragment of cosmid pUKG096, which are located approximately 150 kb from the centromere. It contains four open reading frames (ORFs) which encode potential proteins of more than 100 amino acid residues, as well as the UBI2 gene which carries an intron and does not show up as an ORF in the sequence analysis programs. One of the putative proteins, YKR412, is very rich in serine and has significant homology at the carboxyl end to Nopp140 phosphoprotein. YKR413 has several predicted transmembrane domains. YKR15, which has been recently cloned as the MPL1 gene, encodes a polypeptide that shows homologies to myosin heavy chain and to the cytoskeleton protein Uso1.

The complete sequence of an 18,002 bp segment of Saccharomyces cerevisiae chromosome XI contains the HBS1, MRP-L20 and PRP16 genes, and six new open reading frames.

We report the sequence of an 18,002 bp DNA fragment from the right arm of Saccharomyces cerevisiae chromosome XI. This segment contains nine complete open reading frames (ORFs), YKR401 to YKR409, and part of another ORF, YKR400, covering altogether 87.2% of the entire sequence. One of them, YKR400, encodes an NAD-dependent 5,10-methylene-tetrahydrofolate dehydrogenase. YKR404, YKR405 and YKR406 correspond to the previously characterized HBS1, MRP-L20 and PRP16 genes, coding for a translation elongation factor, a mitochondrial ribosomal protein and an ATP-binding protein, respectively. The putative product of YKR407 contains the zinc-binding region signature of neutral zinc metallopeptidases. The five other ORFs do not show significant homology to any known protein.

The nucleotide sequence of Saccharomyces cerevisiae chromosome XIV and its evolutionary implications.

In 1992 we started assembling an ordered library of cosmid clones from chromosome XIV of the yeast Saccharomyces cerevisiae. At that time, only 49 genes were known to be located on this chromosome and we estimated that 80% to 90% of its genes were yet to be discovered. In 1993, a team of 20 European laboratories began the systematic sequence analysis of chromosome XIV. The completed and intensively checked final sequence of 784,328 base pairs was released in April, 1996. Substantial parts had been published before or had previously been made available on request. The sequence contained 419 known or presumptive protein-coding genes, including two pseudogenes and three retrotransposons, 14 tRNA genes, and three small nuclear RNA genes. For 116 (30%) protein-coding sequences, one or more structural homologues were identified elsewhere in the yeast genome. Half of them belong to duplicated groups of 6-14 loosely linked genes, in most cases with conserved gene order and orientation (relaxed interchromosomal synteny). We have considered the possible evolutionary origins of this unexpected feature of yeast genome organization.

Complete DNA sequence of yeast chromosome XI.

The complete DNA sequence of the yeast Saccharomyces cerevisiae chromosome XI has been determined. In addition to a compact arrangement of potential protein coding sequences, the 666,448-base-pair sequence has revealed general chromosome patterns; in particular, alternating regional variations in average base composition correlate with variations in local gene density along the chromosome. Significant discrepancies with the previously published genetic map demonstrate the need for using independent physical mapping criteria.

Aplicación de VMNI con "Helmet" en la insuficiencia respiratoria aguda secundaria a hemorragia alveolar (Granulomatosis de Wegener) / No disponible

No disponible