Análisis de un flujo de depósitos (debris flow) en la ladera norte del Pico de Orizaba (México)

[Resumen] Los flujos o coladas de depósitos (debris flows) son deslizamientos homogéneos de enormes masas de sedimentos originados como consecuencia de una sobresaturación de agua, pasando a transformarse en una segunda fase en un flujo turbulento, donde toda la masa transportada se mezcla, hasta alcanzar su estado de reposo debido a la pérdida de pendiente, de manera que va a constituir muros laterales (levées) y lóbulos finales (INNES, 1983; JOHNSON y RODINE, 1984). En áreas volcánicas, estos procesos inciden de manera especial en la estabilidad y evolución geomorfológica de las laderas. El lento crecimiento de la vegetación, prácticamente nulo, hace de éstas, áreas inestables con efectos morfológicos de gran magnitud (movimientos en masa).[Abstract] The volcanic areas are influenced by significant slope processes. This study analyzes a debris flow processe on the northern slope of Pico de Orizaba volcano (Mexique). The rapid retreat of the glaciers in this volcano during the past century and the absence of a land cover are suitable conditions to start debris flows processes. The conclusions indicate the importance of the glacial and periglacial activity in this geomorphologic event, the same as in the landform evolution and its activity in relation to climatic change

Identification of novel tail-anchored membrane proteins integrated by the bacterial twin-arginine translocase

\ua9 2024 The Authors. The twin-arginine protein transport (Tat) system exports folded proteins across the cytoplasmic membranes of prokaryotes and the energy transducing-membranes of plant thylakoids and mitochondria. Proteins are targeted to the Tat machinery by N-terminal signal peptides with a conserved twin-arginine motif, and some substrates are exported as heterodimers where the signal peptide is present on one of the partner proteins. A subset of Tat substrates is found in the membrane. Tat-dependent membrane proteins usually have large globular domains and a single transmembrane helix present at the N-or C-terminus. Five Tat substrates that have C-terminal transmembrane helices have previously been characterized in the model bacterium Escherichia coli. Each of these is an iron–sulfur cluster-containing protein involved in electron transfer from hydrogen or formate. Here we have undertaken a bioinformatic search to identify further tail-anchored Tat substrates encoded in bacterial genomes. Our analysis has revealed additional tail-anchored iron–sulfur proteins associated in modules with either a b-type cytochrome or a quinol oxidase. We also identified further candidate tail-anchored Tat substrates, particularly among members of the actinobacterial phylum, that are not predicted to contain cofactors. Using reporter assays, we show experimentally that six of these have both N-terminal Tat signal peptides and C-terminal transmembrane helices. The newly identified proteins include a carboxypeptidase and a predicted protease, and four sortase substrates for which membrane integration is a prereq-uisite for covalent attachment to the cell wall

Clinical approach and treatment of benign and malignant parotid masses, personal experience

Parotid gland tumours account for 80% of all salivary gland neoplasms, 20% of these are malignant, but in daily clinical practice most parotid masses are operated on before obtaining the final histological diagnosis. This clinical setting further complicates the critical point of parotid surgery, which is the management of the facial nerve. In the present study, data were evaluated referring to 540 patients who underwent parotidectomy for a mass which was discovered to be a benign (470 cases) or a malignant (70 cases) neoplasm, between November 1994 and December 2007, at our Institution. The most significant single parameter in this series of malignancies regarding disease specific survival was the clinical involvement of the facial nerve at diagnosis (p = 0.006). Also for this reason, as there is no evidence that liberal VIIth nerve sacrifice improves prognosis, when it is not clinically involved, every attempt is made to dissect and preserve it. At present, the most complicated situation concerning nerve preservation may be, on the other hand, recurrence of a benign tumour, in particular pleomorphic adenoma, which, in our series, has a higher incidence (8.3%) of permanent facial dysfunction, than surgery with nerve preservation for malignancy (3.7%)

Regenerative Strategy for Persistent Periprosthetic Leakage around Tracheoesophageal Puncture: Is It an Effective Long-Term Solution?

Autologous tissue-assisted regenerative procedures have been considered effective to close different types of fistula, including the leakage around tracheoesophageal puncture. The aim of this study was to retrospectively review 10 years of lipotransfer for persistent periprosthetic leakage in laryngectomized patients with voice prosthesis. Clinical records of patients who experienced periprosthetic leakage from December 2009 to December 2019 were reviewed. Patients receiving fat grafting were included. The leakage around the prosthesis was assessed with a methylene blue test. Twenty patients experiencing tracheoesophageal fistula enlargement were treated with fat grafting. At the one-month follow-up, all patients were considered improved with no leakage observed. At six months, a single injection was sufficient to solve 75% of cases (n 15), whereas 25% (n 5) required a second procedure. The overall success rate was 80% (n 16). Results remained stable for a follow-up of 5.54 � 3.97 years. Fat grafting performed around the voice prosthesis, thanks to its volumetric and regenerative properties, is a valid and lasting option to solve persistent periprosthetic leakage

Midfacial fractures: our experience.

Authors report their experience in the treatment of midfacial fractures in 201 patients, 177 of whom underwent surgery for reduction and fixation of the fracture. Since no functional or aesthetic deficits were present, surgery was not performed in the remaining 24 cases. Of the 177 patients, the maxillary complex was involved in 70 (classified as central and centro- lateral fractures), the zygomatic-maxillary-orbital complex in another 70, isolated fractures of the orbital floor blow-out in 18, and. isolated fractures of the zygomatic arch in 19. The re- sults obtained and the degree of satisfaction were evaluated in 90 patients with clinical visits, as well as by telephone inter- view. A total of 88 patients expressed complete satisfaction with the results of the surgical outcome, while the remaining 2 patients were not satisfied with the aesthetic outcome. All pa- tients were operated within 24-48 hours post-trauma in the case of incarceration of extrinsic ocular muscles, and within 10 days in other types of trauma, even in those patients in inten- sive care. The importance of clinical and radiological pre-op- erative diagnosis is stressed as well as the choice of the most suitable therapeutic approach for the different types of frac- tures, considering recent tendencies towards minimally inva- sive procedures to achieve better cosmetic results. The latest developments in fixation techniques with reference to titanium mini- and/or micro-plates that may eventually be substituted with absorbable materials are discussed

Idiopathic SIADH in young patients: dont forget the nose

Il neuroblastoma olfattivo (ONB) è un raro tumore neuroendocrino dei seni paranasali associato, secondo molti autori, alla produzione di molteplici sostanze biologicamente attive. In questo lavoro descriviamo il caso di un paziente di sesso maschile di 31 anni giunto alla nostra osservazione presentando la sindrome idiopatica da inappropriata secrezione di ormone antidiuretico (SIADH). Durante il work-up diagnostico il paziente è stato sottoposto a TAC del massiccio facciale, che documentava la presenza di un estesioneuroblastoma etmoidale. è stato eseguito un trattamento di chirurgia endoscopica e successiva radioterapia. Subito dopo lintervento chirurgico i livelli di natremia si sono normalizzati. Cinque anni più tardi il paziente risulta essere libero da malattia. Attualmente in letteratura sono stati pubblicati 17 casi di SIADH associata a ONB. In nove lavori la SIADH idiopatica ha tempestivamente portato alla diagnosi di masse sinusali come nel nostro caso, tuttavia, in molti casi, si è giunti alla diagnosi corretta mesi o anni dopo. Nei giovani pazienti con sindrome idiopatica da inappropriata secrezione di ormone antidiuretico è necessario escludere un tumore maligno neuroendocrino dei seni paranasali

Role of transcription factor Sp1 and CpG methylation on the regulation of the human podocalyxin gene promoter

BACKGROUND: Podocalyxin (podxl) is a heavily glycosylated transmembrane protein mainly found on the apical membrane of rat podocytes and also in endothelial, hematopoietic, and tumor cells. Despite of its interest no much is known about the transcriptional regulation of podxl in different cells. Thus, we aimed at studying the functional features of the 5'-regulatory region of the human Podxl gene. RESULTS: The promoter region of the human Podxl gene has been cloned and its structure and function were analyzed. The primary DNA sequence is rich in G+C and is devoid of TATA or CAAT boxes. The sequence contains recognition sites for several putative transcription factors; however, the basic promoter activity seems to rely entirely on Sp1 transcription factor since supershift analysis was positive only for this factor. The region encompassed by 66 to -111 nts conferred the minimal transcriptional activity that increases as the number of Sp1 sites augmented with the length of the promoter fragment. In Sp1-lacking insect cells the Podxl promoter constructs showed activity only if cotransfected with an Sp1 expression plasmid. Finally, mutation of the Sp1 sites reduced the promoter activity. We analyzed whether methylation of the CpG dinucleotides present in the first ~600 nts of the promoter region of Podxl could explain the variable rates of expression in different types of cells. Inactivation of methyltransferases by 5'-aza-2'deoxicitidine showed a dose-dependent increase in the podxl content. Moreover, in vitro methylation of the promoter constructs -111,-181 and -210 led to an almost complete reduction of the promoter activity. A correlation was found between the degree of methylation of the CpG promoter dinucleotides and the rate of podxl expression in different cell lines. CONCLUSION: Our results indicate that transcriptional regulation of Podxl is supported primarily by Sp1 site(s) and that DNA-methylation of the CpG promoter islands contributes to control the tissue specific expression of podxl

New insights into the exploitation of vitis vinifera l. Cv. aglianico leaf extracts for nutraceutical purposes

The leaves of Vitis vinifera L. have been used for a long time in traditional medicine for the treatment of many ailments. Grape polyphenols, indeed, have been demonstrated to be able to defend against oxidative stress, responsible for various disorders such as cancer, diabetes and neurodegenerative diseases. The effects of different extraction techniques, Soxhlet (SOX), Accelerated Solvent (ASE 40, ASE 50) and Ultrasound Assisted Extraction (UAE) were studied in this work to evaluate their impact on the chemical profile and bioactive potential of Vitis vinifera L. (cv. Aglianico) leaf extracts. The phytochemical profile was investigated by HPLC-DAD and 9 phenolic compounds were identified and quantified in the extract. Moreover, the antioxidant, anticholinesterase and antityrosinase activities were evaluated. In detail, the total polyphenol content and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl, Oxygen Radical Absorbance Capacities and β-Carotene Bleaching assays) were evaluated and compared to assess the Relative Antioxidant Capacity Index (RACI). To test the inhibitory activity of extracts towards cholinesterases, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition assays were performed. SOX and ASE 50 have shown the highest value of RACI, 0.76 and 0.65, respectively. Regarding enzymatic inhibitory activity, ASE 50 (IC50 = 107.16 ± 8.12 µg/mL) and SOX (IC50 = 171.34 ± 12.12 µg/mL) extracts exhibited the highest AChE and BChE inhibitory activity, respectively, while UAE (IC50 = 293.2 ± 25.6 µg/mL, followed by SOX (IC50 = 302.5 ± 38.3 µg/mL) showed the highest tyrosinase inhibition value. Our results demonstrated for the first time that Aglianico leaves are important sources of phenols that could be used to prevent oxidative stress and be potentially helpful in diseases treatable with tyrosinase and cholinesterase inhibitors, like myasthenia gravis or Alzheimer’s