Monitoring of bioprocesses and thus observation and identification of such processes is one of the main aims of bioprocess engineering. It is of vital importance in bioprocess development to improve ...the overall productivity by avoiding unintentional limitations to ensure not only optimal process conditions but also the observation of established production processes. Furthermore, reproducibility needs to be improved and final product quality and quantity be guaranteed. Therefore, an advanced monitoring and control system has been developed, which is based on different in‐line, on‐line and at‐line measurements for substrates and products. Observation of cell viability applying in‐line radio frequency impedance measurement and on‐line determination of intracellular recombinant target protein using the reporter protein T‐Sapphire GFP based on in‐line fluorescence measurement show the ability for the detection of critical process states. In this way, the possibility for the on‐line recognition of optimal harvest times arises and disturbances in the scheduled process route can be perceived.
An advanced monitoring and control system was developed which is based on different in‐line, on‐line and at‐line measurements for substrates and products. Using the information achieved in this paper, fully automated processes can be established and process strategies can be developed to obtain a higher productivity.
During laparoscopic Nissen fundoplication (LNF), it is unclear whether the short gastric vessels (SGV) should be divided, the crura reapproximated, or the wrap sutured to the crus.
Since first ...performing LNF, we have consistently utilized a <2.5-cm wrap performed over a >50 Fr dilator. Other technical details have varied, and these are reviewed in terms of early clinical outcome. Of 105 consecutive patients undergoing LNF, two were converted to open operation (2%). In the remaining 103 patients with >/=3-month follow-up (mean 17 months), the initial 46 (group 1; 45%, mean age +/- SEM = 47 +/- 2 years) had selective division of the SGV, crural closure, and wrap fixation. In this group, 32 patients (70%) underwent SGV division, 30 patients (65%) had crural closure (10 anteriorly/20 posteriorly), and 14 patients (30%) had the wrap sutured to the crus. During the subsequent 57 LNFs (group 2; 55%, 47 +/- 2 years), all patients underwent SGV division, posterior crural closure, and suture of the wrap to the crus.
Clinical outcome at >/=3 months was compared between the two groups. The frequencies of mild reflux symptoms, meteorism, and persistent dysphagia were similar in the two groups. However, the incidences of slippage of the wrap into the chest and the need for secondary intervention (esophageal dilatation and/or laparoscopic reoperation) decreased significantly from 15% and 13% of patients in group 1, respectively, to no occurrences in group II. Chi-square analyses revealed that combinations of these technical variables were significantly related to the improved outcome in group II.
Based on these data demonstrating improved clinical outcome, we recommend routine division of the SGV, posterior closure of the crura, and fixation of the wrap to the crus during LNF.
The technique of laparoscopic cholecystectomy (LC) has evolved since its adoption in the late 1980s. We sought to document these changes and assess whether patient outcomes were influenced during ...this maturational process.
A prospective data base was used to record the outcomes of all LCs performed in an academic surgeon's practice. Trends over time among 1,165 consecutive patients were assessed by comparing the first 100 LCs (group I), the middle 100 LCs (group II), and the most recent 100 LCs (group III).
During a 93-month period with 1,165 patients undergoing LC, 25 procedures (2.1%) were converted to open cholecystectomy. Perioperative complications occurred in 31 patients (3%): grade I in 9 (0.8%), grade II in 16 (1.4%), grade III in 5 (0.4%), and grade IV (death) in 1 (0.1%). Length of hospital stay and convalescence were 1.1 +/- 0.1 and 9.5 +/- 0.5 days, respectively. Nineteen patients (2%) were readmitted early after operation and 10 (1%) developed long-term complications (port-site hernia or retained stone). In group III, cholangiography was largely replaced by intraoperative ultrasonography for ductal evaluation. Operating room time decreased, while the rates of conversion, morbidity, and readmission remained the same. Patients had higher ASA classifications in the latter two groups, whereas operative charges were greater in Group III than in Groups I and II. These trends occurred even though most procedures are currently performed by residents, and fewer LCs are being done.
Laparoscopic cholecystectomy has matured into a more efficient operation, yet remains safe with low morbidity when performed by residents at an academic institution.
To date, there have been only a few anecdotal reports of laparoscopic hepatectomy, most of which are limited to wedge resections. The aim of this study was to assess the feasibility of laparoscopic ...hepatic lobectomy in a porcine model.
Eight pigs were anesthetized before placement of an abdominal wall lift device and five laparoscopic ports. With the porta hepatis clamped, the left lateral hepatic lobe was divided with an ultrasonic dissector. Small vessels and ducts were clipped, larger vascular structures were transected with staplers, and surface hemorrhage was controlled with an argon beam coagulator. Serum liver enzymes (LFTs) and blood counts were drawn pre- and postoperatively. All animals were killed after 1 week.
Mean +/- SEM operating and clamp times were 131 +/- 8 and 39 +/- 2 min, respectively. There were four intraoperative complications in three animals (three lacerations of the hepatic vein and one tear of the splenic capsule), all of which were controlled at surgery. Mean blood loss was 189 +/- 52 ml, and the mass of the resected specimen was 139 +/- 11 g. There were no postoperative complications or deaths. White blood cell count, hematocrit, and LFTs did not change postoperatively, except for aspartate aminotransferase (AST), which was elevated transiently. There were no bile leaks or intraabdominal abscesses.
Laparoscopic left hepatic lobectomy was technically feasible in the porcine model using an abdominal wall lift device for exposure. Clinical trials are needed to assess its feasibility and limitations before laparoscopic hepatic lobectomy is deemed safe for human use.
Samples of water and sediment were taken from drains, reservoirs and wells from four commercial hardy ornamental nurseries with water recirculation systems. The samples were taken on seven different ...dates throughout a single year from August 1994 to July 1995. The samples were screened for Phytophthora species using five different methods: direct plating, three bait tests (using lupin seedlings, apples and Rhododendron leaves) and a DAS-ELISA (double-antibody sandwich enzyme-linked immunosorbent-assay) with two antisera. In the nurseries with old water recirculation systems, Phytophthora species were detected in the drains and in the reservoirs. In the nursery with a new recirculation system, the pathogens were only present in the drains. None of the water samples from wells in any of the nurseries were contaminated. Phytophthora species were present in the water as well as in the sediment samples from drains and reservoirs. They were detected in the water recirculation systems irrespective of the season. The number of isolates increased about sevenfold between late summer and spring. At least 12 different Phytophthora species were identified: some isolates were previously unrecorded species. The epidemiology of the pathogens in outdoor water recirculation systems as well as the importance of the results for commercial nurseries is discussed.PUBLICATION ABSTRACT
Abstract
Heterorhabditis spp. (Rhabditida: Nematoda) live in a close symbiosis with
the bacterium Photorhabdus luminescens. For biocontrol purposes the
nematodes are produced in liquid culture ...pre-incubated with P. luminescens.
The bacteria produce a food signal, inducing dauer juveniles (DJ) to
initiate development. In rhabditid nematodes the exit from this
developmentally arrested third stage DJ is called recovery. Attempts to
produce Heterorhabditis spp. in liquid culture have often failed due to low
and delayed recovery of the inoculated DJ. The influence of carbon dioxide
as a recovery co-factor was investigated. Increasing concentrations of CO2
enhanced DJ recovery in the presence of the bacterial food signal. The
effect could not be related to a decline of the pH caused by increasing CO2
concentrations. On the contrary, at lower pH the DJ recovery decreased. In
one experiment a considerable spontaneous recovery was observed in the
absence of a food signal. This phenomenon and a variable threshold response
of the DJ to CO2 lead to the assumption that they are differently
pre-disposed to respond to recovery inducing signals. Providing the results
can be confirmed in laboratory scale bioreactors, the control of carbon
dioxide during nematode liquid culture can help to improve the bioreactor
process technology.Heterorhabditis spp. (Rhabditida: Nematoda) leben in
enger Symbiose mit dem Bakterium Photorhabdus luminescens. Für die
biologische Bekämpfung werden die Nematoden in Flüssigkulturen vermehrt, die
vorher mit P. luminescens inkubiert wurden. Die Bakterien produzieren ein
Nahrungssignal, das die Dauerlarven (DJ) veranlasst, ihre Entwicklung wieder
aufzunehmen. Bei rhabditiden Nematoden wird das Verlassen des
entwicklungsphysiologisch gehemmten Dauerlarvenstadiums als “recovery”
bezeichnet. Versuche, Heterorhabditis spp. in Flüssigkultur zu produzieren
sind oft aufgrund einer niedrigen oder verspäteten “recovery” gescheitert.
Der Einfluß von Kohlendioxid als Einflussfaktor auf die “recovery” wurde
untersucht. Zunehmende CO2 Konzentrationen förderten die “recovery” bei
Anwesenheit des Nahrungssignals. Einem mit zunehmender CO2-Konzentration
fallenden pH-Wert konnte die Wirkung nicht zugeschrieben werden. Im
Gegenteil, bei niedrigen pH-Werten nahm die “recovery” ab. In einem
Experiment wurde eine spontane “recovery” beobachtet, ohne dass ein
Nahrungssignal vorhanden war. Dieses Phänomen und die variable Antwort der
Dauerlarven auf gleiche CO2-Konzentrationen lassen den Schluss zu, dass die
Dauerlarven unterschiedlich prädisponiert sind in ihrer Reaktion auf die
“recovery” induzierenden Signale. Vorausgesetzt die Ergebnisse können in
LaborBioreaktoren bestätigt werden, ist die Regelung des Kohlendioxidgehalts
während der Nematoden-Flüssigkultur eine Hilfe die Prozesstechnik zu
optimieren.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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