De operatieve behandeling van pancreatitis

Over de operatieve behandeling van zowel de acute haemorrhagische necrotiserende pancreatitis (A.H.N.P.) als de chronische pancreatitis bestaan nog verschillende opvattingen. Hoewel het twee duidelijk verschillende ziektebeelden van hetzelfde orgaan zijn, hebben ze gemeen. dat de conservatieve therapie veelal faalt en dat nog steeds gezocht wordt naar de juiste indicatie en soort operatie. Op de chirurgische afdeling van het Academisch Ziekenhuis Dijkzigt in Rotterdam werd enige jaren geleden gekozen voor een vrij agressieve operatieve benadering van deze beide ziektebeelden. In dit proefschrift zal van de resultaten van deze benadering verslag gedaan worden. De acute haemorrhagische necrotiserende pancreatitis (A.H.N.P.) en de chronische pancreatitis zijn zoals gezegd, ondanks mogelijke overeenkomsten in de oorzaken van het ontstaan, de pathofysiologie en de klinische symptomatologie. twee los van elkaar staande ziektebeelden. Met name is de problematiek die optreedt bij zowel de diagnostiek als de behandeling zo totaal verschillend. dat het omwille van de duidelijkheid verstandig leek om beide ziektebeelden in een afzonderlijk deel van dit proefschrift te bespreken. Zo worden in hoofdstuk 1 t/m 5 de diagnostiek en de mogelijke behandelingen van A.H.N.P. aan de hand van eigen ervaringen en literatuurgegevens besproken. De bespreking spitst zich toe zowel op een vroegtijdige differentiatie tussen acute oedemateuze pancreatitis en A.H.N.P. als op het feit dat het niet bekend is of, en zo ja hoe, een oedemateuze pancreatitis kan overgaan in een A.H.N.P. Verder komen verschillen van inzicht ter sprake omtrent de keuze van de operatieve behandeling en het tijdstip waarop deze operatieve behandeling het beste kan plaats vinden. In hoofdstuk 6 t/m 9 worden de diagnostiek en de mogelijke behandelingen van chronische pancreatitis aan de hand van eigen ervaringen en literatuurgegevens besproken. Bij chronische pancreatitispatiënten is, in tegenstelling tot bij de A.H.N.P., een veel uitgebreider diagnostiek noodzakelijk zowel naar de lokalisatie van de afwijkingen als naar de aanwezigheid van een exocriene of endocriene pancreasinsufficiëntie. De problemen bij de behandeling worden vooral veroorzaakt door persisterende pijn en gewichtsverlies

Isosorbide dinitrate in the treatment of anal fissure: A randomised, prospective, double blind, placebo-controlled trial.

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Bladder Regeneration Using a Smart Acellular Collagen Scaffold with Growth Factors VEGF, FGF2 and HB-EGF

Tissue engineering may become an alternative to current bladder augmentation techniques. Large scaffolds are needed for clinically significant augmentation, but can result in fibrosis and graft shrinkage. The purpose of this study was to investigate whether smart acellular collagen-heparin scaffolds with growth factors (GFs) VEGF, FGF2, and HB-EGF enhance bladder tissue regeneration and bladder capacity in a large animal model of diseased bladder. Scaffolds of bovine type I collagen with heparin and VEGF, FGF2, and HB-EGF measuring 3.2 cm in diameter were prepared. In 23 fetal sheep, a bladder exstrophy was surgically created at 79 days of gestation. One week after birth (at full term), the bladder was reconstructed by primary closure (PC group) or using a collagen-heparin scaffold with GFs (COLGF group) and compared to a historical group reconstructed with a collagen scaffold without GFs (COL group). Functional (video urodynamics) and histological evaluation was performed 1 and 6 months after bladder repair. The overall survival rate was 57%. Cystograms were normal in all animals, except for low-grade reflux in all groups. Urodynamics showed no statistically significant differences in bladder capacity and compliance between groups. Histological evaluation at 1 month revealed increased urothelium formation, improved angiogenesis, and enhanced ingrowth of smooth muscle cells (SMCs) in the COLGF group compared to the COL group. At 6 months, improved SMC ingrowth was found in the COLGF group compared to the COL group; both scaffold groups showed normal urothelial lining and standard extracellular matrix development. Bladder regeneration using a collagen-heparin scaffold with VEGF, FGF2, and HB-EGF improved bladder tissue regeneration in a large animal model of diseased bladder. Larger GF-loaded constructs need to be tested to reach clinically significant augmentation

Tissue engineering of diseased bladder using a collagen scaffold in a bladder exstrophy model

OBJECTIVE: To compare the regenerative capacity of diseased bladder in a large animal model of bladder exstrophy with regeneration in healthy bladder using a highly porous collagen scaffold. MATERIALS AND METHODS: Highly porous bovine type I collagen scaffolds with a diameter of 32 mm were prepared. In 12 fetal sheep a bladder exstrophy was surgically created at 79 days' gestation. Lambs were born at full term (140 days' gestation). After 1 week the bladder lesion was reconstructed and augmented with a collagen scaffold (group 1). In nine normal newborn lambs the bladder was augmented with a collagen scaffold 1 week after birth (group 2). Functional (video-urodynamics) and histological evaluation was performed at 1 and 6 months after surgery. RESULTS: The survival rate was 58% in group 1 and 100% in group 2. Cystograms were normal in all lambs, besides low-grade reflux in both groups. Urodynamics showed comparable capacity between both groups and a trend to lower compliance in group 1. Histological evaluation at 1 month revealed a non-confluent urothelial layer, an immature submucosa, and initial ingrowth of smooth muscle cells. At 6 months both groups showed normal urothelial lining, standard extracellular matrix development, and smooth muscle cell ingrowth. CONCLUSIONS: Bladder tissue regeneration with a collagen scaffold in a diseased bladder model and in healthy bladder resulted in comparable functional and histological outcome, with a good quality of regenerated tissue involving all tissue layers. Improvements may still be needed for larger augmentations or more severely diseased bladders

Conceptual design of a novel CO2 capture process based on precipitating amino acid solvents

Amino acid salt based solvents can be used for CO2 removal from flue gas in a conventional absorption–thermal desorption process. Recently, new process concepts have been developed based on the precipitation of the amino acid zwitterion species during the absorption of CO2. In this work, a new concept is introduced which requires the precipitation of the pure amino acid species and the partial recycle of the remaining supernatant to the absorption column. This induces a shift in the pH of the rich solution treated in the stripper column that has substantial energy benefits during CO2 desorption. To describe and evaluate this concept, this work provides the conceptual design of a new process (DECAB Plus) based on a 4 M aqueous solution of potassium taurate. The design is supported by experimental data such as amino acid speciation, vapor–liquid equilibria of CO2 on potassium taurate solutions, and solid–liquid partition. The same conceptual design method has been used to evaluate a baseline case based on 5 M MEA. After thorough evaluation of the significant variables, the new DECAB Plus process can lower the specific reboiler energy for solvent regeneration by 35% compared to the MEA baseline. The specific reboiler energy is reduced from 3.7 GJ/tCO2, which corresponds to the MEA baseline, to 2.4 GJ/tCO2, which corresponds to the DECAB Plus process described in this work, excluding the low-grade energy required to redissolve the precipitates formed during absorption. Although this low-grade energy will eventually reduce the overall energy savings, the evaluation of DECAB Plus has indicated the potential of this concept for postcombustion CO2 captur