α-synuclein build-up is alleviated via ESCRT-dependent endosomal degradation brought about by p38MAPK inhibition in cells expressing p25α

α-synucleinopathy is driven by an imbalance of synthesis and degradation of α-synuclein (αSyn), causing a build up of αSyn aggregates and post-translationally modified species, which not only interfere with normal cellular metabolism but also by their secretion propagates the disease. Therefore, a better understanding of αSyn degradation pathways is needed to address α-synucleinopathy. Here, we used the nerve growth factor–differentiated catecholaminergic PC12 neuronal cell line, which was conferred α-synucleinopathy by inducible expression of αSyn and tubulin polymerization-promoting protein p25α. p25α aggregates αSyn, and imposes a partial autophagosome–lysosome block to mimic aspects of lysosomal deficiency common in neurodegenerative disease. Under basal conditions, αSyn was degraded by multiple pathways but most prominently by macroautophagy and Nedd4/Ndfip1-mediated degradation. We found that expression of p25α induced strong p38MAPK activity. Remarkably, when opposed by inhibitor SB203580 or p38MAPK shRNA knockdown, endolysosomal localization and degradation of αSyn increased, and αSyn secretion and cytotoxicity decreased. This effect was specifically dependent on Hsc70 and the endosomal sorting complex required for transport machinery, but different from classical microautophagy, as the αSyn Hsc70 binding motif was unnecessary. Furthermore, in a primary neuronal (h)-αSyn seeding model, p38MAPK inhibition decreased pathological accumulation of phosphorylated serine-129-αSyn and cytotoxicity. In conclusion, p38MAPK inhibition shifts αSyn degradation from various forms of autophagy to an endosomal sorting complex required for transport–dependent uptake mechanism, resulting in increased αSyn turnover and cell viability in p25α-expressing cells. More generally, our results suggest that under conditions of autophagolysosomal malfunction, the uninterrupted endosomal pathway offers a possibility to achieve disease-associated protein degradation.

0255 Comparing Performance, Fatigue and Sleepiness Between Short-Haul And Ultra Long-Haul Commercial Airline Operations

Introduction

Safety performance indicators (SPIs) are used in aviation to determine if a trip that is non-compliant with federal regulations is safe to fly. Exemptions to regulations can be granted if a safety case demonstrates that the SPIs for an alternative means of compliance (AMOC; i.e., a trip outside regulations) are non-inferior to SPIs for a safety standard operation (SSO; i.e. a trip compliant with regulations). Through this process, it has previously been suggested that ultra-long-range flights are non-inferior to long-range flights due to increased sleep opportunity. We determined whether SPIs for non-compliant ultra-long-range (ULR) trips are non-inferior to those for compliant short-haul (SH) trips.

Methods

Performance, fatigue, and sleepiness were assessed at the top of descent (TOD) of flight segments using the Psychomotor Vigilance Task (PVT), Samn-Perelli (SP) fatigue scale, and Karolinska Sleepiness Scale (KSS), respectively. Data were analyzed using non-inferiority testing. Two different ULR trips with different TOD times (ULR trip 1: n=81; ULR trip 2: n=22) were compared to two types of SH trips, including one trip that contained one or more all-night flights (SH trip 1: n=48) and one trip with zero all-night flights (SH trip 2: n=47).

Results

Non-inferiority was found for the SPIs at most comparison points. For example, comparing the SPIs for ULR trip 2 and SH trip 1 at final TOD, non-inferiority was found for all SPIs. In contrast, comparing the SPIs for ULR trip 1 and SH trip 1 at final TOD, non-inferiority was found for SP and KSS, while non-inferiority for PVT was only suggested.

Conclusion

The findings suggest that the AMOC trips are as safe as or safer than the compliant SH trips. This raises questions regarding the structure of SH trips and how differences in the structures play a role in performance, fatigue and sleepiness.

Support

United Airlines

0244 Examining Pilot Safety Performance Indicators at Critical Phases of Flight Across Multiple Flight Legs During Commercial Airline Trips

Introduction

Prior simulation and operational studies have started to address whether the number of consecutive flight segments negatively affects cognitive performance, fatigue, and sleepiness, without reaching a clear consensus. This study expands this literature by determining whether there are significant changes in cognitive performance, fatigue, and sleepiness at critical phases of flight across multiple flight segments, while accounting for the number of segments, flight direction, trip day, and time-of-day.

Methods

Fifty commercial airline pilots were studied. Each pilot flew two separate short-haul trips, each ranging from 1–4 days and 1–10 flight segments. Cognitive performance, fatigue, and sleepiness were assessed at top-of-climb (TOC) and top-of-descent (TOD) of each flight segment and each trip day. Cognitive performance, fatigue, and sleepiness were assessed using Psychomotor Vigilance Task (PVT) speed, Samn-Perelli (SP) ratings, and Karolinska Sleepiness Scale (KSS) ratings, respectively. Data were analyzed using Wilcoxon t-tests and verified using ANOVAs.

Results

Mean PVT speed (Cohen’s d =0.57), SP ratings (Cohen’s d = 0.73), and KSS ratings (Cohen’s d = 0.63) were significantly worse at TOD than TOC (p < 0.001); and, significantly varied across flight segments (p<0.001). Cognitive performance, fatigue, and sleepiness were consistently and significantly degraded around the fifth flight segment, improved around the sixth to eighth flights segments, and were subsequently degraded around the eighth to tenth flight segments.

Conclusion

The results indicate that cognitive performance, fatigue, and sleepiness vary across flight segments, trip day, and phase of flight. Results suggest that these safety performance indices degrade after five segments, and further degrade after eight flight segments. The results presented could be used to inform future airline scheduling and regulation.

Support

This work has been supported by United Airlines.

Is Positron Emission Tomography Using 18F-Fluorodeoxyglucose and 11C-Acetate Valuable in Diagnosing Indeterminate Pancreatic Masses?

Background:

It can be impossible to differentiate a mass forming chronic pancreatitis from adenocarcinoma of the pancreas using standard anatomical imaging. Positron emission tomography using 2-[18F] fluoro-2deoxy-D-glucose (18FDG-PET) and 1-[11C]-acetate (11C-acetate-PET) are methods taking advantage of the metabolic differences between benign and malignant tissues.

Aims:

To determine the diagnostic accuracy of 18FDG-PET and 11C-acetate-PET in indeterminate pancreatic masses.

Methods:

Twenty patients with an indeterminate mass of the head of the pancreas were prospectively studied. All patients underwent 18FDG-PET and eighteen of them 11C-acetate-PET. Scans were evaluated qualitatively and quantitatively; the later by using regional standardised uptake value (SUV). Final diagnosis was established using histopathologic evaluation of resected specimen or biopsy.

Results:

Adenocarcinoma was diagnosed in twelve patients and chronic pancreatitis in eight. Qualitative evaluation of 18FDG-PET imaging revealed three false negative and one false-positive results. The sensitivity, specificity, and diagnostic accuracy were 75 %, 88 %, and 80 %, respectively. The cut-off SUV to differentiate malignant from benign disease was 3,5 demonstrating a sensitivity of 91.7 % and a specificity of 75 %.

Conclusion:

18FDG-PET imaging could not confirm or exclude malignancy in indeterminate masses of the head of the pancreas with high sensitivity and diagnostic accuracy. 11C-acetate-PET provided no additional diagnostic benefits.

Reciprocal signals between microglia and neurons regulate α-synuclein secretion by exophagy through a neuronal cJUN-N-terminal kinase-signaling axis

Background

Secretion of proteopathic α-synuclein (α-SNC) species from neurons is a suspected driving force in the propagation of Parkinson’s disease (PD). We have previously implicated exophagy, the exocytosis of autophagosomes, as a dominant mechanism of α-SNC secretion in differentiated PC12 or SH-SY5Y nerve cells. Here we have examined the regulation of exophagy associated with different forms of nerve cell stress relevant to PD.

Results

We identify cJUN-N-terminal kinase (JNK) activity as pivotal in the secretory fate of autophagosomes containing α-SNC. Pharmacological inhibition or genetic (shRNA) knockdown of JNK2 or JNK3 decreases α-SNC secretion in differentiated PC12 and SH-SY5Y cells, respectively. Conversely, expression of constitutively active mitogen-activated protein kinase kinase 7 (MKK7)-JNK2 and -JNK3 constructs augment secretion. The transcriptional activity of cJUN was not required for the observed effects. We establish a causal relationship between increased α-SNC release by exophagy and JNK activation subsequent to lysosomal fusion deficiency (overexpression of Lewy body-localized protein p25α or bafilomycin A1). JNK activation following neuronal ER or oxidative stress was not correlated with exophagy, but of note, we demonstrate that reciprocal signaling between microglia and neurons modulates α-SNC secretion. NADPH oxidase activity of microglia cell lines was upregulated by direct co-culture with α-SNC-expressing PC12 neurons or by passive transfer of nerve cell-conditioned medium. Conversely, inflammatory factors secreted from activated microglia increased JNK activation and α-SNC secretion several-fold in PC12 cells. While we do not identify these factors, we extend our observations by showing that exposure of neurons in monoculture to TNFα, a classical pro-inflammatory mediator of activated microglia, is sufficient to increase α-SNC secretion in a mechanism dependent on JNK2 or JNK3. In continuation hereof, we show that also IFNβ and TGFβ increase the release of α-SNC from PC12 neurons.

Conclusions

We implicate stress kinases of the JNK family in the regulation of exophagy and release of α-SNC following endogenous or exogenous stimulation. In a wider scope, our results imply that microglia not only inflict bystander damage to neurons in late phases of inflammatory brain disease but may also be active mediators of disease propagation.

Tubulin polymerization-promoting protein (TPPP/p25α) promotes unconventional secretion of α-synuclein through exophagy by impairing autophagosome-lysosome fusion

Aggregation of α-synuclein can be promoted by the tubulin polymerization-promoting protein/p25α, which we have used here as a tool to study the role of autophagy in the clearance of α-synuclein. In NGF-differentiated PC12 catecholaminergic nerve cells, we show that de novo expressed p25α co-localizes with α-synuclein and causes its aggregation and distribution into autophagosomes. However, p25α also lowered the mobility of autophagosomes and hindered the final maturation of autophagosomes by preventing their fusion with lysosomes for the final degradation of α-synuclein. Instead, p25α caused a 4-fold increase in the basal level of α-synuclein secreted into the medium. Secretion was strictly dependent on autophagy and could be up-regulated (trehalose and Rab1A) or down-regulated (3-methyladenine and ATG5 shRNA) by enhancers or inhibitors of autophagy or by modulating minus-end-directed (HDAC6 shRNA) or plus-end-directed (Rab8) trafficking of autophagosomes along microtubules. Finally, we show in the absence of tubulin polymerization-promoting protein/p25α that α-synuclein release was modulated by dominant mutants of Rab27A, known to regulate exocytosis of late endosomal (and amphisomal) elements, and that both lysosomal fusion block and secretion of α-synuclein could be replicated by knockdown of the p25α target, HDAC6, the predominant cytosolic deacetylase in neurons. Our data indicate that unconventional secretion of α-synuclein can be mediated through exophagy and that factors, which increase the pool of autophagosomes/amphisomes (e.g. lysosomal disturbance) or alter the polarity of vesicular transport of autophagosomes on microtubules, can result in an increased release of α-synuclein monomer and aggregates to the surroundings.

Effects of F/G-actin ratio and actin turn-over rate on NADPH oxidase activity in microglia

Background

Most in vivo studies that have addressed the role of actin dynamics in NADPH oxidase function in phagocytes have used toxins to modulate the polymerization state of actin and mostly effects on actin has been evaluated by end point measurements of filamentous actin, which says little about actin dynamics, and without consideration for the subcellular distribution of the perturbed actin cytoskeleton.

Results

Here, we in addition to toxins use conditional expression of the major actin regulatory protein LIM kinase-1 (LIMK1), and shRNA knock-down of cofilin to modulate the cellular F/G-actin ratio in the Ra2 microglia cell line, and we use Fluorescence Recovery after Photobleaching (FRAP) in β-actin-YFP-transduced cells to obtain a dynamic measure of actin recovery rates (actin turn-over rates) in different F/G-actin states of the actin cytoskeleton. Our data demonstrate that stimulated NADPH oxidase function was severely impaired only at extreme actin recovery rates and F/G-actin ratios, and surprisingly, that any moderate changes of these parameters of the actin cytoskeleton invariably resulted in an increased NADPH oxidase activity.

Conclusion

moderate actin polymerization and depolymerization both increase the FMLP and PMA-stimulated NADPH oxidase activity of microglia, which is directly correlated with neither actin recovery rate nor F/G- actin ratio. Our results indicate that NADPH oxidase functions in an enhanced state of activity in stimulated phagocytes despite widely different states of the actin cytoskeleton.

Stimulus-dependent regulation of the phagocyte NADPH oxidase by a VAV1, Rac1, and PAK1 signaling axis

The p21-activated kinase-1 (PAK1) is best known for its role in the regulation of cytoskeletal and transcriptional signaling pathways. We show here in the microglia cell line Ra2 that PAK1 regulates NADPH oxidase (NOX-2) activity in a stimulus-specific manner. Thus, conditional expression of PAK1 dominant-positive mutants enhanced, whereas dominant-negative mutants inhibited, NADPH oxidase-mediated superoxide generation following formyl-methionyl-leucylphenylalanine or phorbol 12-myristate 13-acetate stimulation. Both Rac1 and the GTP exchange factor VAV1 were required as upstream signaling proteins in the formyl-methionyl-leucyl-phenylalanine-induced activation of endogenous PAK1. In contrast, PAK1 mutants had no effect on superoxide generation downstream of FcgammaR signaling during phagocytosis of IgG-immune complexes. We further present evidence that the effect of PAK1 on the respiratory burst is mediated through phosphorylation of p47(Phox), and we show that expression of a p47(Phox) (S303D/S304D/S320D) mutant, which mimics phosphorylation by PAK1, induced basal superoxide generation in vivo. In contrast PAK1 substrates LIMK-1 or RhoGDI are not likely to contribute to the PAK1 effect on NADPH oxidase activation. Collectively, our findings define a VAV1-Rac1-PAK1 signaling axis in mononuclear phagocytes regulating superoxide production in a stimulus-dependent manner.

Recurrent inguinal hernia: randomized multicenter trial comparing laparoscopic and Lichtenstein repair

BACKGROUND

The optimal treatment for recurrent inguinal hernia is of concern due to the high frequency of recurrence.

METHODS

This randomized multicenter study compared the short- and long-term results for recurrent inguinal hernia repair by either the laparoscopic transabdominal preperitoneal patch (TAPP) procedure or the Lichtenstein technique.

RESULTS

A total of 147 patients underwent surgery (73 TAPP and 74 Lichtenstein). The operating time was 65 min (range, 23-165 min) for the TAPP group and 64 min (range, 25-135 min) for the Lichtenstein group. Patients who underwent TAPP reported significantly less postoperative pain and shorter sick leave (8 vs 16 days). The recurrence rate 5 years after surgery was 19% for the TAPP group and 18% for the Lichtenstein group.

CONCLUSION

The short-term advantage for patients who undergo the laparoscopic technique is less postoperative pain and shorter sick leave. In the long term, no differences were observed in the chronic pain or recurrence rate.

Current use of thromboembolism prophylaxis for laparoscopic cholecystectomy patients in Sweden

BACKGROUND

The need for thromboembolism (TE) prophylaxis during laparoscopic surgery is not well established. The aim of this study was to investigate current TE prophylaxis in patients undergoing laparoscopic cholecystectomy (LC) in Sweden.

METHODS

Mail questionnaire to all Surgical Departments in Sweden about the current use of thromboembolism prophylaxis in patients undergoing laparoscopic cholecystectomy.

RESULTS

The response rate was 78 of 80 departments of surgery (98%). Seventy reported performing LC. Thirty-six percent used thromboembolism prophylaxis in all patients, 17% in most, 9% in half their patients and 39% only rarely. The current use of thromboembolism prophylaxis ranged from low-molecular-weight heparin for 7 days + stockings in all patients to no prophylaxis at all in the majority of patients.

CONCLUSIONS

The use of thromboembolism prophylaxis in LC patients is highly variable, even in the small and homogenous country of Sweden. Further studies concerning the risk of TE complications after laparoscopic surgery are warranted.

Renal hemodynamics during carbon dioxide pneumoperitoneum: an experimental study in pigs

BACKGROUND

Laparoscopic living donor nephrectomy is increasingly being performed, although the effects of carbon dioxide pneumoperitoneum (CO2 PP) on renal function and hemodynamics and the levels of vasopressin are not well studied.

METHODS

Renal blood flow, renal venous pressure, urine output, and vasopressin concentrations in renal venous blood were measured in pigs subjected to 12 mmHg of CO2 PP for 150 min.

RESULTS

Renal blood flow was decreased at induction of PP and increased during the first 30 min after exsufflation. Renal venous pressure was increased during PP. There was indirect evidence of a decrease in urine output during PP. No changes in renal venous vasopressin concentrations were seen.

CONCLUSION

A CO2 PP of 12 mmHg causes changes in renal hemodynamics and urine output. No changes in vasopressin levels were seen in this pig model, suggesting that other explanations for the observed changes must be sought.

Ultrasound-guided percutaneous cholecystostomy in high-risk surgical patients

BACKGROUND AND AIMS

In critically ill patients, cholecystectomy is associated with a high mortality rate. The aim of this study was to evaluate the safety, efficacy and long-term outcome of ultrasound-guided percutaneous cholecystostomy (USGPC) in critically ill patients with acute cholecystitis.

MATERIALS AND METHODS

Clinical records of 51 patients, all considered high-risk surgical patients, with acute cholecystitis treated with USGPC between 1987 and 1999, were retrospectively reviewed. Response was defined as improvement in clinical symptoms and signs, and/or reduction in c-reactive protein and white blood count levels within 72 h. Long-term results were evaluated by means of clinical records and written correspondence.

RESULTS

Gallbladder stones were seen in 28 patients whereas 23 had acalculous cholecystitis. Ninety percent showed clinical improvement after USGPC. Cholecystectomy was performed in 16%, of which 6% after recurrent cholecystitis. Recurrence of cholecystitis occurred in 22%. Hospital mortality was 16%. None of the deaths was procedure related or related to acute cholecystitis alone. Major complications relating to the USGPC were rare (4%), while minor catheter-related complications were quite common.

CONCLUSIONS

USGPC is a procedure with few complications and a high success rate. In patients with acalculous cholecystitis as well as in many patients with calculous cholecystitis, no further treatment was needed.

Trimethoprim-sulphamethoxazole and metronidazole as prophylaxis in colorectal surgery: a study of bioavailability after an oral single dose

OBJECTIVE

To evaluate oral single dose prophylaxis in colorectal surgery.

DESIGN

Prospective study.

SETTING

University hospital, Sweden.

SUBJECTS

24 patients (13 women; 11 men; mean age 57 years, range 27-81) listed for elective colorectal operations.

INTERVENTION

At 0630 on the day of the operation all patients were given an oral dose of trimethoprim-sulphamethoxazole (TMP 160 mg and SMZ 800 mg) and metronidazole (2 g). The serum concentrations of TMP and SMZ were analysed in venous samples taken at the start and end of each operation.

RESULTS

The earliest operation started at 0830 and the last finished at 1700. The median (range) serum concentrations of TMP were 1.4 (0.7-2.6) mg/L (start) and 1.3 (1.0-2.8) mg/L (end), and of SMZ 35 (15-65) mg/L (start) and 33 mg (13-70) mg/L (end). The individual values were above or equal to the minimal inhibitory concentration (TMP 0.8 mg/L; SMZ 15.2 mg/L) for relevant gram-negative species.

CONCLUSION

Oral TMP/SMZ in the morning gives satisfactory serum concentrations independently of when the operation is done during the day. The regimen is simple and has the potential for being an effective alternative to intravenous prophylaxis.

Intramucosal pH and pCO(2) do not strictly correlate with intestinal energy metabolism in experimental peritonitis

This study aimed to investigate tissue hypoxia on the cellular level in sepsis. Eighteen pigs weighing 18-27 kg were studied. Intramucosal-arterial PCO(2) gradient (PCO(2)-gap) and intramucosal pH (pH(i)) were calculated using tonometry. A blind loop of the small intestine was constructed for repeated tissue biopsies to measure intestinal energy-related metabolites and lactate concentration. Six animals served as controls. In 12 animals, faecal peritonitis was induced. Six of these animals were studied without further interventions, while the others were resuscitated with dextran to maintain cardiac index at baseline level. Untreated peritonitis caused an increase in PCO(2)-gap and a drop in pH(i). The intestinal energy metabolism was not disturbed until the end of the experimental period, with a decreased energy charge value and a moderately increased lactate concentration. In peritonitis-dextran animals, PCO(2)-gap and pH(i) remained at baseline level and the energy metabolism was not disturbed. We conclude that in peritonitis, PCO(2)-gap - like pH(i) - can be influenced by other factors than strictly anaerobic tissue metabolism.

Coagulation activation after laparoscopic cholecystectomy in spite of thromboembolism prophylaxis

BACKGROUND

The aim of this study was to determine whether laparoscopic cholecystectomy (LC), in spite of its minimally invasive nature, causes coagulation activation.

METHODS

Sixty-four patients undergoing LC were included prospectively. All received either dextran or low-molecular-weight heparin (LMWH). Blood samples taken the morning of the operation and the following morning were analyzed for TAT, FM, fragment 1+2, tPA, PAI-1, vWf, D-dimer, Hb, hematocrit, and APC resistance.

RESULTS

Significant increases in TAT, FM, fragment 1+2, and D-dimer were seen, whereas APC resistance, Hb, and hematocrit decreased significantly. Dextran led to a decrease in vWf and no change in tPA, whereas LMWH led to an increase in both these parameters.

CONCLUSIONS

Laparoscopic cholecystectomy causes coagulation activation. There are differences in the response between patients receiving dextran and LMWH as thromboembolism prophylaxis. Since most patients are discharged the day after the operation, there could be practical as well as theoretical advantages to using dextran.

Bacterial translocation in experimental shock is dependent on the strains in the intestinal flora

BACKGROUND

Enteric microorganisms are responsible for a significant proportion of post-surgical infections. Intestinal mucosal injury may permit translocation of bacteria and endotoxin. This study investigates translocation in peritonitis and ischemia/reperfusion by inoculating different bacterial species into the small intestine.

METHODS

Twenty-five pigs were monitored hemodynamically and divided into three groups: controls (C), ischemia/reperfusion (I/R), and peritonitis (P). Intramucosal pH (pHi) was calculated tonometrically. A perfusion tube was positioned in the ileum for inoculation of the bacterial strains. In a first study period a non-pathogenic bacterium was used, whereas Escherichia coli strains with known ability to translocate were used in a second. Blood and mesenteric lymph nodes (MLNs) were obtained for bacterial culture and endotoxin analyses.

RESULTS

Mesenteric arterial blood flow and pHi decreased in groups I/R and P. Endotoxin levels increased in these groups in period 1, whereas in period 2 an increase over time was only observed in group P. No bacterial translocation to blood or MLNs occurred in period 1. In period 2 bacteria translocated to MLNs in all animals, including controls. Translocation to central and/or mesenteric venous blood was found in all groups, but mainly in I/R and P. The incidence of mucosal injury was similar in the two periods.

CONCLUSIONS

Since positive blood and MLN samples were only found in period 2, we conclude that translocation of bacteria seems to be more dependent on the presence of translocating strains in the intestinal bacterial flora than on the mucosal insult.

Intestinal blood flow and intramucosal pH in experimental peritonitis

BACKGROUND AND AIMS

Experimental peritonitis causes gut intramucosal acidosis indicating intramucosal ischemia. However, tissue acidosis may reflect other conditions than ischemia. An increased mucosal-arterial Pco2 difference ( Pco2-gap) is suggested to be a more adequate measure of tissue ischemia than intramucosal pH (pHi). This study was performed to elucidate whether keeping cardiac index (CI) and splanchnic blood flow normal or supranormal by administration of colloids and an inotropic drug could prevent the acidosis as well as reduce the Pco2-gap. A secondary aim was to study to what degree the low pHi in peritonitis really reflects ischemia.

SUBJECTS

24 anesthetized pigs (18-27 kg) divided into four groups.

MODELS

A Swan-Ganz catheter, transonic flow meters and catheters for blood sampling were applied. pHi was calculated using tonometry. Standardized fecal peritonitis was induced, except in controls. One peritonitis group was given dextran (Group P(DEX)) and another in addition dobutamine (Group PDOB) to keep CI normal or supranormal, respectively.

RESULTS

After 4 h, a significant drop in pHi was found in all peritonitis groups, most pronounced in untreated peritonitis (to 7.09+/-.02). Corresponding values in Group P(DEX) and Group P(DOB) were 7.22+/-.03 and 7.22+/-.01, respectively, and in controls 7.30+/-.02. The Pco2-gap and the mucosal-arterial [H+] difference ([H+]-gap) increased significantly in untreated peritonitis but did not increase in groups given dextran and dextran + dobutamine.

CONCLUSION

Maintaining CI in peritonitis attenuated the reduction in pHi and prevented the increased Pco2- and [H+]-gap. It seems justified from these data to conclude that the somewhat reduced pHi in treated peritonitis groups did not reflect tissue ischemia.

An experimental porcine model of partial ischaemia of the distal colon

OBJECTIVE

Ischaemia of the colon is a major challenge in aortoiliac surgery. The aim was to establish an animal model of partial distal colonic ischaemia to study interventional strategies.

DESIGN

Randomised experiment.

SETTING

University Hospital. Department of Experimental Research.

MATERIAL

19 pigs.

INTERVENTIONS

11 Pigs were subjected to ischaemia consisting of total occlusion of the inferior mesenteric artery and partial occlusion of the superior mesenteric artery. Eight animals were sham controls. Dextran was given.

MAIN OUTCOME MEASURES

Haemodynamic measurements, intramucosal pH-measurements (pHi) and histological grading.

RESULTS

Both ischaemic animals and controls remained haemodynamically stable. It was possible to maintain stable ischaemia in the distal colon in the pHi-range of 6.9-7.1. There was histological mucosal damage of the distal colon in ischaemic animals but not in controls.

CONCLUSIONS

The model could be of value when studying interventional strategies to reduce or reverse ischaemia.

Incidence of thromboembolic complications after laparoscopic cholecystectomy: review of the literature

The purpose of this study was to quantify the risk of thromboembolic complications after laparoscopic cholecystectomy by a survey of the literature. We reviewed 60 laparoscopic cholecystectomy series consisting of 153,832 patients. The average mortality was 0.08%. The average rate of fatal pulmonary embolism was 0.02% and total pulmonary embolism 0.06%. The average rate of reported deep vein thrombosis was 0.03%. We conclude that laparoscopic cholecystectomy is a safe procedure, and the rate of clinically evident postoperative thromboembolic complications is probably lower than after conventional cholecystectomy. A lingering bias due to the overrepresentation of young and healthy patients early in the era of laparoscopic cholecystectomy could, however, still affect these figures. An underreporting of the lesser complications is likely. The risk is not negligible, though, and some authors have recommended thromboembolism prophylaxis, although further studies are necessary to find the optimal prophylaxis strategy. The true incidence is possible to establish only by using objective diagnostic methods for surveillance.

DNA binding sites recognised in vitro by a knotted class 1 homeodomain protein encoded by the hooded gene, k, in barley (Hordeum vulgare)

The homeodomain of the knotted classes of transcription factors from plants differs from the well characterized Antp/En type homeodomains from Drosophila at key amino acid residues contributing to the DNA binding. A cDNA, Hvh21, derived from the hooded gene and encoding a full length homolog of knotted1 from maize was isolated from barley seedlings and expressed as a maltose binding protein fusion in E. coli. The purified HvH21-fusion protein selected DNA fragments with 1-3 copies of the sequence TGAC. Gel shift experiments showed that the TGAC element was required for binding and the results further indicate that the HvH21-fusion protein binds DNA as a monomer.

Hemodynamic changes in the inferior caval vein during pneumoperitoneum. An experimental study in pigs

BACKGROUND

Laparoscopic procedures of increasing difficulty and duration are becoming more and more common. This may cause significant challenges to the circulatory system and possibly influence thrombogenicity.

METHODS

Experimental study of carbon dioxide pneumoperitoneum in pigs.

RESULTS

Inferior caval vein blood flow remained unchanged, whereas inferior caval vein pressure increased during pneumoperitoneum. Inferior caval vein, pulmonary, and systemic vascular resistance increased during pneumoperitoneum and remained increased after exsufflation.

CONCLUSIONS

Pneumoperitoneum leads to an increased inferior caval vein pressure, which could cause a dilation of peripheral veins. The similar patterns of vascular resistance in the inferior caval vein, pulmonary artery, and systemic arteries (a gradual increase remaining elevated after exsufflation) suggest a common humoral factor or increased sympathetic nerve activity.

Small intestinal mucosal pH and lactate production during experimental ischemia-reperfusion and fecal peritonitis in pigs

The aim of this study was to investigate mucosal pH and lactate production in a porcine model of ischemia/reperfusion and sepsis using both tonometry and a technique for segmental intestinal perfusion. Eighteen pigs (17-23 kg) were anesthetized and mechanically ventilated. They were divided into three groups and followed for 4 h. Group C (n = 6) served as controls. In the ischemia/reperfusion group (I/R; n = 6), the superior mesenteric artery was totally occluded for 60 min. In group P (n = 6), sepsis was induced by fecal peritonitis. Cardiac index (CI) was determined by thermodilution and blood flow in the superior mesenteric artery (QSMA), using a Transonic flow probe. Intramucosal pH (pHi) was calculated using tonometry. A special balloon tube for segmental perfusion was introduced in the midileum for lactate measurement. Lactate and oxygen saturation were measured in arterial blood and in the superior mesenteric vein. CI, QSMA, pHi, and lactate in blood and perfusate remained unchanged in controls. Occlusion of intestinal blood flow induced a fall in pHi from 7.28 +/- .02 to 6.76 +/- .04, a marked rise in lactate in the perfusate, and an increased arteriovenous lactate difference. During reperfusion, pHi tended to return to baseline values. Lactate in the perfusate and the arteriovenous lactate difference decreased. In sepsis there was a continuous reduction in CI and QSMA to 45 +/- 13% and 40 +/- 20% of baseline, respectively. pHi decreased moderately from 7.22 +/- .09 to 6.98 +/- .25. Lactate remained unchanged in blood and perfusate. Microscopic mucosal injury was observed in all animals subjected to ischemia/reperfusion and in three of six pigs in group P. A good association between pHi and lactate production was seen in ischemia/reperfusion. However, in sepsis, lactate in superior mesenteric venous blood or in intestinal perfusate did not increase, despite the fall in pHi. The mechanism causing ischemic mucosal injury has different characteristics in sepsis and in ischemia caused by arterial occlusion.

The management of liver cell cancer

Hepatocellular carcinoma (HCC) is a highly malignant tumour. It presents a considerable management problem. In this review the natural history of HCC is summarized. Surgical and non-surgical treatment modalities are reviewed. Finally, combined treatments are described.

Teaching reading to disabled readers with language disorders: a controlled evaluation of synthetic speech feedback

In a long-term study two groups of language and reading impaired students (N = 15 + 15) were reading with the aid of segmented speech-feedback in a computerized program. One group received feedback that was simultaneously segmented visually and auditorily into syllables, the other received feedback by letter names. In both groups subjects were expected to synthesize segments into words and to compare their synthesis to whole word feed-back subsequently provided by the computer. They worked for half a lesson (approximately 20 minutes) a day for a total of 40 days. During this period the experiment groups progressed more in reading than a control group of age and reading-level-matched students (N = 35) who received traditional remedial instruction. The group in the syllable condition gained slightly more in non-word reading and in syllable segmentation than did the letter group. Differences in gains in reading abilities were not explained by differences in age, but to some extent by initial level of phoneme and syllable awareness. Future applications of the speech-feedback system are discussed.

Changes in gut intramucosal pH and gut oxygen extraction ratio in a porcine model of peritonitis and hemorrhage

OBJECTIVE

To establish the relationship between gut intramucosal pH and blood flow to the gut, gut oxygen delivery, and gut oxygen extraction ratio in a porcine model of peritonitis and hemorrhage.

DESIGN

Prospective, controlled study.

SETTING

Experimental laboratory in a university teaching hospital.

SUBJECTS

Thirty pigs of both sexes, weighing 15 to 22 kg.

INTERVENTIONS

Animals were anesthetized, intubated, and mechanically ventilated. A flow probe was placed around the superior mesenteric artery for registration of blood flow. A tonometer was placed in the lumen of midileum for calculation of gut intramucosal pH. Hourly, for 5 hrs, blood samples were taken from mixed venous, mesenteric venous, and arterial blood. Five animals served as controls, ten animals had peritonitis induced by fecal instillation in the abdominal cavity, five were bled stepwise, five were bled rapidly (to a mean arterial pressure of 30 mm Hg), and five were bled rapidly and reinfused after 3 hrs.

MEASUREMENTS AND MAIN RESULTS

Both peritonitis and hemorrhage caused decreases in gut blood flow and intramucosal pH. In mild peritonitis, the intramucosal pH decrease preceded that of blood flow. In all experimental groups, oxygen delivery decreased over time; in both mild and severe peritonitis, this decrease was preceded by a decrease of intramucosal pH. Intramucosal pH correlated well with gut oxygen extraction ratio in peritonitis (r2 = .86). In hemorrhage, there was a correlation of r2 = .66, but in intramucosal pH of < 7.12, a further decrease was accompanied only by minor changes in extraction ratio.

CONCLUSIONS

Since a reduction in blood flow was preceded by a decrease in intramucosal pH, low intramucosal pH in peritonitis cannot be explained by low flow alone. Gut oxygen delivery proved to be a poor indicator of gut acidosis (i.e., low intramucosal pH). In peritonitis, a decreasing intramucosal pH was associated with an increasing oxygen extraction ratio. In hemorrhage, this association had a sharp deflection point below which a further decrease in intramucosal pH occurred concomitantly with an unchanged gut oxygen extraction ratio. Increased extraction ratio was not sufficient, not even initially, to maintain aerobic metabolism (i.e., unchanged intramucosal pH).

Hepatic extraction of hyaluronic acid in porcine peritonitis

The hepatic extraction of hyaluronic acid (HA) was studied in porcine fecal peritonitis in two groups of animals given various amounts of volume substitution. There was a progressive decrease in hepatic blood flow (QH) and a corresponding increase in the plasma concentration of HA in arterial blood over a 5-hour observation period, less pronounced in animals given more volume substitution. While hepatic clearance of HA decreased, the extraction ratio over the liver was not altered. The extracted amount of HA, which at steady state reflects the turnover of HA, was also unchanged. There was a significant correlation between QH and arterial HA concentration (r = 0.57; p < 0.05). The data suggest that the arterial HA concentration in sepsis reflects QH rather than an altered ability of the liver to eliminate HA.

Detection of liver ischemia using microdialysis during experimental peritonitis in pigs

The liver oxygen delivery (DO2) and consumption (VO2) were measured in a porcine model of septic shock induced by fecal peritonitis. Lactate and hypoxanthine were simultaneously monitored in hepatic extracellular fluid and in central venous blood using a microdialysis technique. Animals were divided into a control group (n = 6) and a peritonitis group (n = 6). Peritonitis was induced by installation of a standardized amount of autologous feces into the abdominal cavity. The animals were followed for 5 h. The changes in the liver during peritonitis were, a decreased DO2, a increased, maintained, or decreased VO2, an increased oxygen extraction, and a loss of net hepatic lactate uptake. Parallel to these changes, systemic lactic acidosis developed. Intrahepatic lactate and hypoxanthine increased during peritonitis reflecting liver ischemia. The increase of these metabolites was seen concomitantly in the liver and in central venous blood. There was a wide variability of the individual response to the septic challenge among the animals. The limited hepatic oxygen delivery, and the increased needs for oxygen led to flow-dependent oxygen consumption, and signs of liver ischemia in severe sepsis. Intrahepatic and intravenous microdialysis may be useful for monitoring of the individual time course of hepatic and systemic ischemia in sepsis.

Inhibition of CD18-dependent adherence of polymorphonuclear leukocytes does not affect liver oxygen consumption in fecal peritonitis in pigs

We tested the hypothesis that circulating polymorphonuclear leukocytes (PMNs), adhering to endothelium of the liver vascular bed are involved in the alterations of the liver oxygen delivery (DO2) and consumption (VO2) that is a result of fecal peritonitis in pigs. Twenty-two pigs were divided into three groups. Animals in group I (n = 7) served as controls. Fecal peritonitis was induced in groups II (n = 7) and III (n = 8). Animals in group III were pretreated with IB4, a monoclonal anti-CD18 antibody inhibiting adherence of PMNs to the endothelium. Peritonitis increased liver VO2 in groups II and III in spite of decreased liver DO2. In group I, circulating PMNs increased during the experimental period. Sepsis caused a decrease in the number of circulating PMNs in group II, an effect that was fully counteracted in group III, where the number of PMNs rose to control level. Myeloperoxidase activity and morphometric determination of PMN infiltration in liver biopsies virtually paralleled the circulating PMN count. Although fecal peritonitis is followed by a CD18-dependent leukopenia that can be counteracted by pretreatment with an anti-CD18 antibodies, this treatment does not affect the alteration in liver VO2 and DO2 observed.

Hepatic oxygen consumption and cytochrome P450 activity in experimental faecal peritonitis

OBJECTIVE

To study hepatic oxygen consumption and cytochrome P450 activity in pigs with septic shock induced by faecal peritonitis.

DESIGN

Controlled experimental study.

ANIMALS

12 pigs weighing 19-27 kg.

INTERVENTION

The animals were divided into a control group (n = 6) and a peritonitis group (n = 6). Peritonitis was induced by intraperitoneal instillation of a standard amount of autologous faeces. The animals were then observed for 300 minutes. Liver biopsy specimens were taken at 0 and 300 minutes.

MAIN OUTCOME MEASURES

Hepatic oxygen delivery (DO2) and consumption (VO2). Cytochrome P450 activity was studied by measuring O- and N-demethylation of codeine at 0 and 300 minutes.

RESULTS

Hepatic DO2 was reduced, whereas VO2 was increased during sepsis. There were no significant changes in the N- and O-demethylation of codeine.

CONCLUSIONS

Hepatic VO2 did increase during sepsis, possibly because of the increased metabolic demand. Cytochrome P450 activity was unaffected by the septic challenge.

[Laparoscopic surgery. A shift in paradigm?]

Since it was first introduced at the beginning of the century, laparoscopy has been developed by pioneers in the field of gynaecological surgery from a diagnostic aid to a high tech tool for use in various branches of surgery. In the near future, this rapidly developing technique, with three-dimensional video and robot-assisted surgery, will require well planned theoretical and practical training.

Early gut ischemia in experimental fecal peritonitis

Tissue oxygenation in the gastrointestinal tract was studied in a porcine model in which septic shock was induced by fecal peritonitis. The oxygen delivered was estimated by measuring the portal venous blood flow and the calculated arterial oxygen saturation. The oxygen consumption of the gut, including the pancreas and spleen, was monitored by measuring the portal venous blood flow and the difference between the calculated arterial oxygen and the measured portal venous oxygen saturation. In addition, the oxygenation of the gut mucosa was followed via the tonometric technique. Furthermore, lactate was measured in arterial and portal blood. The experimental animals were divided into two groups, one control (n = 6) and one experimental (n = 6). Peritonitis was introduced by installation of a standardized amount of autologous feces into the abdominal cavity. The animals were followed for 5 hr. Very early during the course of sepsis there was a fall in gut intramucosal pH (pHi), and this was evident before any reduction in splanchnic DO2. Furthermore, an early increase in splanchnic VO2 was evident simultaneously with the fall in pHi. Arterial pH and lactate were not able to detect the inadequate regional tissue oxygenation. It is concluded that pHi measured with the tonometric technique is sensitive in detecting gut mucosal ischemia, and it is therefore highly likely that tonometry would be a valuable method in monitoring severe ill patients.

Splanchnic and total body oxygen consumption in experimental fecal peritonitis in pigs: effects of dextran and iloprost

Tissue oxygenation in the gastrointestinal tract and in the liver was studied in a porcine model where septic shock was induced by fecal peritonitis. The effects of different fluid regimes were compared. In one group (n = 8) a moderate amount of crystalloid fluids was given, in another (n = 7) crystalloids and colloids, and in a third group (n = 6) iloprost, a prostacyclin analogue, was administered intra-arterially (10 ng x kg-1 b.w. x min-1) in combination with the crystalline and colloid fluid regime. Septic shock induced by fecal peritonitis reduced cardiac index and oxygen supply to splanchnic organs. Iloprost improved the hepatic arterial blood flow, and tended to attenuate the reduction in liver oxygen delivery. Oxygen consumption (VO2) in the gastrointestinal tract and the liver was significantly increased in the group given crystalloids. These animals developed a hypovolemic/hypodynamic septic shock. Liver VO2 in these animals became flow dependent reflected by increasing hepatic venous lactate values and inversion of lactate turnover by the liver. In the two other groups gastrointestinal and liver VO2 remained constant during the observation period. Oxygen extraction over the liver increased when oxygen delivery decreased. The increased liver VO2 is suggested to be secondary to impaired microcirculation and accumulation of macrophages and leukocytes in the septic liver.

Splanchnic oxygen consumption in septic and hemorrhagic shock

Oxygen consumption (VO2) is dependent on oxygen delivery (DO2) in septic shock. Local hypoxia with later secondary organ failure may develop, however, despite an often hyperdynamic circulation. The splanchnic organs seem to be of vital importance in this context. In experiments performed in pigs we compared total body VO2 and DO2 with oxygen consumption and delivery in the gastrointestinal organs and the liver in two different shock states: (1) septic shock induced by peritonitis (n = 6) and (2) hemorrhagic shock (n = 6). Another group of six animals not in shock served as controls. Total, gastrointestinal, and liver DO2 decreased in a similar pattern in both septic and hemorrhagic shock. Gastrointestinal and liver VO2 increased in sepsis, whereas it was unchanged in hemorrhage. In the later phase of sepsis, liver VO2, but not gastrointestinal VO2, again decreased, because liver oxygen extraction was almost total and liver DO2 decreased further. The development of flow-dependent liver hypoxia was reflected in a decrease in liver lactate turnover (increased liver lactate release) during late sepsis. Early hypoxia in the splanchnic region is suggested as a plausible mechanism behind the development of secondary organ failure, especially in sepsis.

[Drug utilization in Hvalsö. An attempt to change the attitude of the population and physicians to drug use]

All of the prescriptions, a total of 1,876, issued by the five practitioners in Hvalsø in four chosen weeks in 1987/88 were copied. The prescribed drugs, a total of 3,177, were calculated for the individual groups of drugs and corrected for the age distribution among the population as a whole and in the individual doctor's practice. The main results from the following groups of drugs are presented here: hypnotics, drugs for neurosis, antibiotics, drugs for cardiac and circulatory disease, drugs for asthma, contraceptive pills and female sex hormones. By and large, considerably more medicine was prescribed for women than for men. For example, twice as much medicine for insomnia was prescribed for women. This is enough for every fourth woman over the age for 70 years to receive a daily dose of hypnotics. Women appear to commence using hypnotics at the age of 40 years and men at 60 years. Marked differences were found in the patterns of prescription between the individual practitioners and thei is apparently greatest as regards prescriptions for men while the more liberal prescription of hypnotics to women was observed for all of the practitioners. Two groups of drugs were, however, prescribed mostly for men, viz, asthma medicine for all age groups and cardiac and circulatory medicine for persons greater than 60 years. Where all of the groups of drugs were concerned, comparisons were undertaken between the prescription habits of the individual practitioners. The results of this investigation are employed in local health work among the population, in study circle work among the practitioners and as basic ideas for the county drug committee activities.

Jejunoileal bypass for morbid obesity. Report of a series with long-term results

Of 72 patients who underwent jejunoileal bypass because of morbid obesity, 69 could be evaluated with special reference to long-term (median 11 years) results. One of the other three had fatal anastomotic leakage, one underwent resection and reversal of shunt because of postoperative gangrene in the bypassed segment, and one died of sepsis and liver failure following cholecystectomy 6 months after bypass. The median body mass index (kg/m2) fell from 45.4 preoperatively to 33.2 after 16 years. Shunt-related complications in early and late follow-up were diarrhoea (n = 15), anal/perianal disorders (15), arthralgia (15), urinary calculi (16), cholelithiasis (5), severe flatulence (7), liver cirrhosis (5), intestinal tuberculosis (1), ileitis (1), severe electrolyte disturbance (4), hypomagnesaemia (22), hypokalaemia (8), and deficiency of vitamin B12 (24), iron (24) and folate (17). Although jejunal bypass effectively reduces weight, the patients are at continuous risk of many complications. However, the improvement in quality of life should not be underestimated.

Bone lesions of acne fulminans. Case report and review of the literature

Acne fulminans, which is the most severe form of acne, affects mainly teenage men; its pathogenesis is unknown. In its most severe form bone lesions may occur, and although they appear to be transient, they cause considerable discomfort to the patient. Roentgenologically these lesions are not well defined, and often biopsies are performed to rule out malignancy or infection. The result of bone biopsies has, however, always been reported to be benign, as they are in this case. We report a case of acne fulminans with a distinct presentation of bone lesion in a technetium 99 scan and findings of high levels of C3 and C4 and low levels of serum estradiol. These changes have not been described before and are contrary to previously published findings.

Acute solitary diverticulitis of the caecum. Case report

In two cases of suspected appendicitis, laparotomy revealed an inflammatory mass medially in the caecum. Colonic resection was performed in both cases and the final diagnosis was solitary caecal diverticulitis. When inflammation of a caecal diverticulum is recognized at laparotomy, simple diverticulectomy is the procedure of choice, but colonic resection is recommended if malignancy cannot be excluded or inflammatory changes are severe.

Quantitation of facial affection in scleroderma

The interincisor distance, the vertical lip distance, and the horizontal oral distance were measured in 68 patients with generalized scleroderma and in 66 healthy individuals. Interincisor distance and vertical lip distance were decreased in scleroderma (p less than 0.001 and p less than 0.001). Vertical lip distance and horizontal oral distance provided clinically a clear differentiation between minor and major affection (p less than 0.001 and p less than 0.001), while the interincisor distance provided a weaker differentiation (p less than 0.05). The horizontal oral distance correlated with the duration of scleroderma (r = -0.289, p less than 0.05), and the vertical lip distances tended to do so (r = -0.208, n.s.). In healthy individuals interincisor and vertical lip distances decreased significantly with age (in males only), while the horizontal oral distance showed no significant decrease. In conclusion, interincisor and vertical lip distances are preferable for diagnosis and the horizontal oral distance for follow-up of facial scleroderma. If only one vertical parameter is wanted, the authors prefer the vertical lip distance to the interincisor distance.