Predictive Potential of Biomarkers of Intestinal Barrier Function for Therapeutic Management with Teduglutide in Patients with Short Bowel Syndrome

INTRODUCTION

The human intestinal tract reacts to extensive resection with spontaneous intestinal adaptation. We analyzed whether gene expression analyses or intestinal permeability (IP) testing could provide biomarkers to describe regulation mechanisms in the intestinal barrier in short bowel syndrome (SBS) patients during adaptive response or treatment with the glucagon-like peptide-2 analog teduglutide.

METHODS

Relevant regions of the GLP-2 receptor gene were sequenced. Gene expression analyses and immunohistochemistry were performed from mucosal biopsies. IP was assessed using a carbohydrate oral ingestion test.

RESULTS

The study includes 59 SBS patients and 19 controls. Increases in gene expression with teduglutide were received for sucrase-isomaltase, sodium/glucose cotransporter 1, and calcium/calmodulin serine protein kinase. Mannitol recovery was decreased in SBS but elevated with teduglutide (Δ 40%), showed a positive correlation with remnant small bowel and an inverse correlation with parenteral support.

CONCLUSIONS

Biomarkers predicting clinical and functional features in human SBS are very limited. Altered specific gene expression was shown for genes involved in nutrient transport but not for genes controlling tight junctions. However, mannitol recovery proved useful in describing the absorptive capacity of the gut during adaptation and treatment with teduglutide.

SAT0407 FOLLOW-UP EXAMINATION FOR THE DETECTION OF POTENTIAL PSORIATIC ARTHRITIS BY FLUORESCENCE OPTICAL IMAGING – IN COMPARISON TO MUSCULOSKELETAL ULTRASOUND

Background:

Up to 30% of all plaque-type psoriasis patients develop psoriatic arthritis (PsA) (1). Early diagnosis of PsA can be difficult due to its heterogenous manifestation and the lack of disease- specific biomarkers, but it is crucial for disease outcome. Recently, our group has shown that fluorescence optical imaging (FOI) can be a helpful diagnostic tool for early PsA diagnosis since it can differentiate between patients with confirmed PsA and suspected PsA (2).

Objectives:

To follow-up patients by FOI with confirmed and suspected PsA with special focus on the group of patients in which PsA could be confirmed between baseline and follow-up – and to compare with the findings of musculoskeletal ultrasound (US).

Methods:

Patients included in our previous study (1) were re-evaluated by FOI of both hands in a standardized manner using the predefined phases 1-3 (p1-p3) and the PrimaVistaMode (PVM). US in greyscale (GS) and power Doppler (PD) were performed of the clinically dominant hand (for tenderness and/or swelling) in the dorsal and palmar view at wrist, MCP, PIP and DIP 2-5 joint levels for synovitis and tenosynovitis.

Subsequently, a comparison of the findings in the affected joints was performed using US as the reference method. Furthermore, AUC was calculated to show the extent to which a new joint inflammation was associated with a change in diagnosis.

Results:

Of the 60 patients initially examined (1), 30 patients (dropout rate 50%) were followed-up approximately 3 years later. The patients were newly divided into 3 groups: Diagnosed PsA (n=14, Group I), still suspected PsA, (n=6, Group II) and in-between diagnosed PsA (n=10, Group III). Patients with a change in the diagnosis from suspected to diagnosed PsA (Group III) showed a significantly increased prevalence of joints with pathological findings in FOI (46% at baseline, 88% at follow-up; p=0.046), with an unchanged joint distribution pattern, i.e. with a dominant involvement of the DIP joints. Compared to baseline, patients of group III were three times more common to show enrichment in p3 in FOI at follow-up (1.7% vs. 7.0%; p=n.s.). Newly detected pathologic joints by FOI (PVM, p2) and US at follow-up were positively associated with the change of diagnosis from suspected PsA to confirmed PsA (FOI: AUC 0.78; GSUS: AUC 0.77).Using US in greyscale as reference, inflammatory changes in the joints were diagnosed in all 3 cohorts by means of FOI in P1 and P3 with high specificity (Group III: 90.6%, Group II: 97.5%, Group I: 94.2%) and low sensitivity (Group III: 24.4%, Group II: 20.3%, Group I: 19.8%).

Conclusion:

FOI appears to be helpful to differentiate between acute and chronic disease stages. Furthermore, it is specific for detecting inflammatory changes in the joints of the hands in PsA – in comparison to US. FOI could thereby become a helpful tool as a “dermatological-screening” method to select psoriasis patients with indication for further rheumatological evaluation.

References:

[1]Zachariae H. Prevalence of Joint Disease in Patients with Psoriasis: Implications for therapy. Am J Clin Dermatol. 2003;4(7):441–447. Review.

[2]Erdmann-Keding M, Ohrndorf S, Werner SG, et al. Fluorescence optical imaging for the detection of potential psoriatic arthritis in comparison to musculoskeletal ultrasound. J Dtsch Dermatol Ges. 2019;17(9):913-921.

Disclosure of Interests:

Juliane Büttner: None declared, Anne-Marie Glimm: None declared, Georgios Kokolakis: None declared, Magdalena Erdmann-Keding: None declared, Gerd Rüdiger Burmester Consultant of: AbbVie Inc, Eli Lilly, Gilead, Janssen, Merck, Roche, Pfizer, and UCB Pharma, Speakers bureau: AbbVie Inc, Eli Lilly, Gilead, Janssen, Merck, Roche, Pfizer, and UCB Pharma, Jens Klotsche: None declared, Sarah Ohrndorf: None declared

Short-Term Overfeeding with Dairy Cream Does Not Modify Gut Permeability, the Fecal Microbiota, or Glucose Metabolism in Young Healthy Men

Background

High-fat diets (HFDs) have been linked to low-grade inflammation and insulin resistance.

Objective

The main purpose of the present study was to assess whether acute overfeeding with an HFD affects insulin sensitivity, gut barrier function, and fecal microbiota in humans.

Methods

In a prospective intervention study, 24 healthy men [mean ± SD: age 23.0 ± 2.8 y, body mass index (in kg/m2) 23.0 ± 2.1] received an HFD (48% of energy from fat) with an additional 1000 kcal/d (as whipping cream) above their calculated energy expenditure for 7 d. Insulin sensitivity (hyperinsulinemic euglycemic clamp), gut permeability (sugar and polyethylene glycol absorption tests, plasma zonulin), and gut microbiota profiles (high-throughput 16S rRNA gene sequencing) were assessed before and after overfeeding, and 14 d after intervention. Additionally, inflammation markers such as high-sensitivity C-reactive protein, lipopolysaccharide-binding protein, leptin, high-molecular-weight adiponectin, calprotectin, regulated on activation normal, T cell expressed and secreted (RANTES), and monocyte chemoattractant protein-1 were measured in plasma by ELISA. Finally, lipid parameters were analyzed in serum by a laboratory service.

Results

Although participants gained 0.9 ± 0.6 kg (P < 0.001) body weight, overnutrition was not associated with a significant change in insulin sensitivity (M value and glucose disposal). Overfeeding for 7 d resulted in elevated serum total (10.2%), LDL (14.6%) and HDL (14.8%) cholesterol concentrations (P < 0.01). In contrast, fasting plasma triglyceride significantly declined (29.3%) during overfeeding (P < 0.001). In addition, there were no significant changes in inflammatory markers. Urine excretion of 4 sugars and polyethylene glycol, used as a proxy for gut permeability, and plasma concentration of zonulin, a marker of paracellular gut permeability, were unchanged. Moreover, overfeeding was not associated with consistent changes in gut microbiota profiles, but marked alterations were observed in a subgroup of 6 individuals.

Conclusions

Our findings suggest that short-term overfeeding with an HFD does not significantly impair insulin sensitivity and gut permeability in normal-weight healthy men, and that changes in dominant communities of fecal bacteria occur only in certain individuals. The study was registered in the German Clinical Trial Register as DRKS00006211.

Effect of caloric restriction on gut permeability, inflammation markers, and fecal microbiota in obese women

Recent findings suggest an association between obesity, loss of gut barrier function and changes in microbiota profiles. Our primary objective was to examine the effect of caloric restriction and subsequent weight reduction on gut permeability in obese women. The impact on inflammatory markers and fecal microbiota was also investigated. The 4-week very-low calorie diet (VLCD, 800 kcal/day) induced a mean weight loss of 6.9 ± 1.9 kg accompanied by a reduction in HOMA-IR (Homeostasis model assessment-insulin resistance), fasting plasma glucose and insulin, plasma leptin, and leptin gene expression in subcutaneous adipose tissue. Plasma high-molecular weight adiponectin (HMW adiponectin) was significantly increased after VLCD. Plasma levels of high-sensitivity C-reactive protein (hsCRP) and lipopolysaccharide-binding protein (LBP) were significantly decreased after 28 days of VLCD. Using three different methods, gut paracellular permeability was decreased after VLCD. These changes in clinical parameters were not associated with major consistent changes in dominant bacterial communities in feces. In summary, a 4-week caloric restriction resulted in significant weight loss, improved gut barrier integrity and reduced systemic inflammation in obese women.

[Sciatic nerve block "out-of-plane" distal to the bifurcation: effective and safe]

BACKGROUND

Ultrasound guided distal sciatic nerve block (DSB) at bifurcation level shows fast onset and provides excellent success rates. However, its safe performance might be difficult for the unexperienced physician. Just slightly distal to the bifurcation, the tibial nerve (TN) and common fibular nerve (CFN) can be shown clearly separated from each other. Therefore, we investigated if a block done here would provide similar quality results compared to the DSB proximally to the division, with a potentially lower risk of nerve damage.

METHODS

In this randomized, prospective trial, 56 patients per group received either a DSB distal to the bifurcation "out-of-plane" (dist.) or proximally "in-plane" (prox.) with 30 ml of Mepivacaine 1% each. Success was tested by a blinded examiner after 15 and 30 min respectively (sensory and motor block of TN and CFN: 0 = none, 2 = complete, change of skin temperature). Videos of the blocks were inspected by an independent expert retrospectively with regard to the spread of the local anesthetic (LA) and accidental intraneural injection.

RESULTS

Cumulative single nerve measurements and temperature changes revealed significant shorter onset and better efficacy (dist/prox: 15 min: 3.13 ± 1.86/1.82 ± 1.62; 30 min: 5.73 ± 1.92/3.21 ± 1.88; T_{15 min}: 30.3 ± 3.48/28.0 ± 3.67, T_{30 min}. 33.0 ± 2.46/30.6 ± 3.86; MV/SD; ANOVA; p < 0.01) combined with a higher rate of subparaneural spread in the dist. group (41/51 vs.12/53; χ2; p < 0,01). Procedure times were similar. There were no complications in either group.

DISCUSSION

The subparaneural spread of the LA turned out to be crucial for better results in the distal group. The steep angle using the out-of-plane approach favors needle penetration through the paraneural sheath. The distance between the branches allows the safe application of the LA, so an effective block can be done with just one injection.

CONCLUSION

DSB slightly distal to the bifurcation, in an out-of-plane technique between the TN and CFN, can be done fast, effectively and safe.

Myosin IXb variants and their pivotal role in maintaining the intestinal barrier: a study in Crohn's disease

BACKGROUND

Myosin IXb (MYO9B) is involved in the regulation of epithelial barrier function. We hypothesized that MYO9B variants are associated with increased intestinal permeability measured in patients with Crohn's disease (CD), where barrier dysfunction is crucially involved in disease development.

METHODS

We sequenced MYO9B and genotyped five MYO9B variants (rs1545620, rs1457092, rs2279003, rs2305764 and rs2279002) and correlated these data to measurement of intestinal permeability in German CD patients (n = 122) obtained by standard oral sugar test using the lactulose/mannitol ratio after measurement of urinary excretion. We furthermore studied MYO9B variants in three European cohorts with inflammatory bowel disease (IBD) and healthy controls : Germany (CD = 264; ulcerative colitis = 143 [UC]; HC = 372); Hungary (CD = 147; UC = 117; HC = 195), the Netherlands (CD = 157; HC = 219).

RESULTS

We found an association for four studied MYO9B variants to an increased intestinal permeability in CD patients (rs1545620, p = 0.010; rs1457092, p = 0.024; rs2279003, p = 0.003; rs2305764, p = 0.015). Furthermore, we observed significantly higher absolute values of intestinal permeability for individuals carrying risk alleles within MYO9B. Looking for an overall disease association, only the rs2305764 variant was associated with CD in the Dutch cohort (p = 0.004), but not in the German or Hungarian cohort. No association to UC or a distinct phenotype in both CD and UC patients was observed for all studied MYO9B variants.

CONCLUSION

Our data suggest a link between MYO9B variants to an increased intestinal permeability in CD patients. This supports the influence of Myosin IXb on the integrity of the epithelial barrier. The role of MYO9B variants in the overall susceptibility to IBD, however, remains to be elucidated.

Increased small intestinal permeability in ulcerative colitis: rather genetic than environmental and a risk factor for extensive disease?

BACKGROUND

A disturbed epithelial barrier could play a pivotal role in ulcerative colitis (UC). We performed a family-based study analyzing in vivo gastrointestinal permeability in patients with UC, their healthy relatives, spouses, and controls.

METHODS

In total, 89 patients with UC in remission, 35 first-degree relatives (UC-R), 24 nonrelated spouses (UC-NR), and 99 healthy controls (HC) were studied. Permeability was assessed by a sugar-drink test using sucrose (gastroduodenal permeability), lactulose/mannitol (intestinal permeability), and sucralose (colonic permeability). Data were correlated with clinical characteristics including medical treatment.

RESULTS

Increased intestinal permeability was detected significantly more often in UC patients in remission (25/89, 28.1%) compared with HC (6/99, 6.1%; P < 0.001). Similar results were obtained in UC-R (7/35, 20.0%; P = 0.01 compared with HC) regardless of sharing the same household with the patients or not. No difference was found between UC-NR (3/24, 12.5%) and HC. Notably, in UC patients increased intestinal permeability was found in 12/28 patients (42.9%) with pancolitis, 7/30 (23.3%) patients with left-sided colitis, and in 2/19 (10.5%) patients with proctitis (P = 0.04). Gastroduodenal and colonic permeability were similar in all groups. Among patients on azathioprine, increased intestinal permeability was only seen in 1/18 (5.6%) patients. In contrast, in 24/70 (34.3%) patients without azathioprine, an increased intestinal permeability was found (P = 0.005).

CONCLUSIONS

An increased intestinal but not colonic permeability was found in UC patients in clinical remission that could mark a new risk factor for extensive disease location. Similar findings in healthy relatives but not spouses suggest that this barrier defect is genetically determined.

The JAK2 variant rs10758669 in Crohn's disease: altering the intestinal barrier as one mechanism of action

PURPOSE

The aetiology of intestinal barrier dysfunction in Crohn's disease (CD) is poorly understood. Associations in relatives of CD families suggest a genetic basis, but the relevant variants are still unknown. We hypothesized that variants in genes occurring in pathways such as autophagy and IL23 signalling might contribute to CD by altering intestinal permeability.

METHODS

We analysed five variants (rs10758669 within JAK2, rs744166 within STAT3, rs4958847, rs11747270 and rs13361189 within IRGM) in adult German inflammatory bowel disease patients (CD, n = 464; ulcerative colitis (UC), n = 292) and matched healthy controls (n = 508). These data were correlated with gastrointestinal permeability as assessed by lactulose/mannitol ratio in CD patients (n = 141) in remission.

RESULTS

Our data confirm the association between JAK2 rs10758669 (p = 0.026, OR = 1.25, 95% CI = 1.04-1.50) and STAT3 rs744166 (p = 0.04, OR = 0.83, 95% CI = 0.688-0.998) with CD, but not UC. With respect to all the analysed IRGM variants, no association was found to either CD or UC. Among CD patients, an increased intestinal permeability was detected in 65 out of 141 patients (46.1%). Most importantly, patients carrying the C risk allele within JAK2 rs10758669 displayed an increased permeability more often compared with patients without the C allele (p = 0.004). No association with intestinal permeability was found for STAT3 rs744166 and all IRGM variants.

CONCLUSIONS

JAK2 rs10758669 and STAT3 rs744166 increase susceptibility for CD. We show that the A>C substitution in rs10758669 of the JAK2 gene is associated with increased intestinal permeability. Altering intestinal barrier function might thus be one mechanism how JAK2 contributes to CD pathogenesis.

Hereditary apolipoprotein AI-associated amyloidosis in surgical pathology specimens: identification of three novel mutations in the APOA1 gene

Apolipoprotein AI-derived (AApoAI) amyloidosis may present either as a non-hereditary form with wild-type protein deposits in atherosclerotic plaques or as a hereditary form due to germline mutations in the APOA1 gene. Currently, more than 50 apoAI variants are known, and 13 are associated with amyloidosis. We describe six patients with AApoAI amyloidosis due to APOA1 germline mutations that affect the larynx, small intestine, large intestine, heart, liver, kidney, uterus, ovary, or pelvic lymph nodes. In each patient, the amyloid showed a characteristic apple green birefringence when viewed under polarized light after Congo red staining and was immunoreactive with antibodies against apoAI. Sequence analyses revealed one known (p.Leu75Pro) and three novel APOA1 mutations that included gene variations leading to two different frameshifts (p.Asn74fs and p.Ala154fs) and one amino acid exchange (p.Leu170Pro). These three novel mutations extend our knowledge about both the location of the mutations and the organ distribution in hereditary AApoAI amyloidosis. Thirteen of the now sixteen amyloidogenic mutations are localized in two hot-spot regions that span residues 50 to 93 and 170 to 178. The organ distribution and clinical presentation of AApoAI amyloidosis seems to depend on the position of the mutation. Patients with alterations in codons 1 to 75 mostly develop hepatic and renal amyloidosis, while carriers of mutations in residues 173 to 178 mainly suffer from cardiac, laryngeal, and cutaneous amyloidosis.

No association of the CARD8 (TUCAN) c.30T>A (p.C10X) variant with Crohn's disease: a study in 3 independent European cohorts

BACKGROUND

A recent study reported that the c.30T>A (p.Cys10Ter; rs2043211) variant, in the CARD8 (TUCAN) gene, is associated with Crohn's disease (CD). The aim of this study was to analyze the frequency of p.C10X in 3 independent European (IBD) cohorts from Germany, Hungary, and the Netherlands.

METHODS

We included a European IBD cohort of 921 patients and compared the p.C10X genotype frequency to 832 healthy controls. The 3 study populations analyzed were: (1) Germany [CD, n = 317; ulcerative colitis (UC), n = 180], (2) Hungary (CD, n = 149; UC, n = 119), and (3) the Netherlands (CD, n = 156). Subtyping analysis was performed in respect to NOD2 variants (p.Arg702Trp, p.Gly908Arg, c.3020insC) and to clinical characteristics. Ethnically matched controls were included (German, n = 413; Hungarian, n = 202; Dutch, n = 217).

RESULTS

We observed no significant difference in p.C10X genotype frequency in either patients with CD or patients with UC compared with controls in all 3 cohorts. Conversely to the initial association study, we found a trend toward lower frequencies of the suggestive risk wild type in CD from the Netherlands compared with controls (P = 0.14). We found neither evidence for genetic interactions between p.C10X and NOD2 nor the C10X variant to be associated with a CD or UC phenotype.

CONCLUSIONS

Analyzing 3 independent European IBD cohorts, we found no evidence that the C10X variant in CARD8 confers susceptibility for CD.

A study in three European IBD cohorts confirms that the ATG16L1 c.898A>G (p.Thr300Ala) variant is a susceptibility factor for Crohn's disease

BACKGROUND AND AIMS

A recent study reported that a nonsynonymous SNP rs2241880 (c.898A>G, p.Thr300Ala) within ATG16L1 confers susceptibility to Crohn's disease (CD). We analyzed ATG16L1 c.898A>G in three independent European inflammatory bowel disease (IBD) cohorts from Germany, Hungary and the Netherlands.

METHODS

In total, we included 910 European IBD patients and compared the ATG16L1 c.898A>G genotype frequency with 707 ethnically matched healthy controls. We included patients from 3 populations originating from Germany (CD n=310; ulcerative colitis [UC] n=179), Hungary (CD n=147; UC n=117), and the Netherlands (CD n=157). Subtyping analysis was performed in respect to CARD15 alterations and clinical characteristics.

RESULTS

We found a highly significant association of c.898A>G to CD. The association was significant (p=0.0005) for the total CD cohort but also for the individual populations from Germany (p=0.02) and Netherlands (p=0.02) whereas in the Hungarian CD patients a clear trend was observed (p=0.19; OR 1.227, 95% CI 0.910; 1.654). No association was found between c.898A>G and UC. No statistical interactions were observed between ATG16L1 c.898A>G and CARD15 variants. Furthermore no association to a CD subphenotype was detected.

CONCLUSIONS

We confirm that ATG16L1 variant c898A>G confers a risk variant for CD but is not associated with a distinct CD phenotype.

Heterozygosity for IL23R p.Arg381Gln confers a protective effect not only against Crohn's disease but also ulcerative colitis

BACKGROUND

A recent study reported that a non-synonymous single nucleotide polymorphism (rs11209026, p.Arg381Gln) located in the IL23R gene is a protective marker for inflammatory bowel disease.

AIM

To analyse the frequency of p.Arg381Gln in three independent European inflammatory bowel disease cohorts and to evaluate how this variant influences disease behaviour.

METHODS

We assessed a European cohort of 919 inflammatory bowel disease patients and compared the IL23R p.Arg381Gln genotype frequency with 845 healthy controls. Inflammatory bowel disease patients originated from Germany [Crohn's disease (CD): n = 318; ulcerative colitis (UC): n = 178], Hungary (CD: n = 148; UC: n = 118) and the Netherlands (CD: n = 157). Ethnically matched controls were included. We performed subtyping analysis in respect to CARD15 alterations and clinical characteristics.

RESULTS

The frequency of the glutamine allele of p.Arg381Gln was significantly lower in inflammatory bowel disease patients compared with controls in a pooled analysis of all three cohorts (P < 0.000001) as well as in the individual cohorts (Germany: P = 0.001, Hungary: P = 0.02 and the Netherlands: P = 0.0002). The p.Arg381Gln genotype distribution was similar between CD and UC. We did not observe either statistical interactions between p.Arg381Gln and CARD15 variants or any significant associations between p.Arg381Gln genotype and subphenotypes.

CONCLUSIONS

The p.Arg381Gln IL23R variant confers a protective effect against both CD and UC, but does not determine disease phenotype.

Possible role of MDR1 two-locus genotypes for young-age onset ulcerative colitis but not Crohn's disease

BACKGROUND

The role of the single nucleotide polymorphisms (SNPs) on positions 2677G>T/A and 3435C>T of the multi-drug-resistance gene 1 (MDR1) in inflammatory bowel disease (IBD) remains unclear.

AIMS

To further elucidate the potential impact of MDR1 two-locus genotypes on susceptibility to IBD and disease behaviour.

PATIENTS AND METHODS

Three hundred eighty-eight German IBD patients [244 with Crohn's disease (CD), 144 with ulcerative colitis (UC)] and 1,005 German healthy controls were genotyped for the two MDR1 SNPs on positions 2677G>T/A and 3435C>T. Genotype-phenotype analysis was performed with respect to disease susceptibility stratified by age at diagnosis as well as disease localisation and behaviour.

RESULTS

Genotype distribution did not differ between all UC or CD patients and controls. Between UC and CD patients, however, we observed a trend of different distribution of the combined genotypes derived from SNPs 2677 and 3435 (chi(2) = 15.997, df = 8, p = 0.054). In subgroup analysis, genotype frequencies between UC patients with early onset of disease and controls showed significant difference for combined positions 2677 and 3435 (chi(2) = 16.054, df = 8, p = 0.034 for age at diagnosis >or=25, lower quartile). Herein the rare genotype 2677GG/3435TT was more frequently observed (odds ratio = 7.0, 95% confidence interval 2.5 - 19.7). In this group severe course of disease behaviour depended on the combined MDR1 SNPs (chi(2) = 16.101, df = 6, p = 0.017 for age at diagnosis >or=25). No association of MDR1 genotypes with disease subgroups in CD was observed.

CONCLUSIONS

While overall genotype distribution did not differ, combined MDR1 genotypes derived from positions 2677 and 3435 are possibly associated with young age onset of UC and severe course of disease in this patient group.

Inflammation and infection complications of 2285 perineural catheters: a prospective study

BACKGROUND

Perineural catheters (PNCs) are increasingly being used. Few data are available on the infectious complications of PNCs. The incidence and localization of local inflammation and infection associated with PNCs were assessed.

METHODS

PNCs placed under sterile conditions for regional anesthesia and post-operative analgesia were evaluated prospectively. Local inflammation was defined as redness, swelling or pain on pressure at the catheter insertion site. Infection was defined as purulent material at the catheter insertion site with or without the need for surgical intervention.

RESULTS

In total, 2285 PNCs were evaluated: 600 axillary, 303 interscalene, 92 infraclavicular, 65 psoas compartment, 574 femoral, 296 sciatic and 355 popliteal. Local inflammation occurred in 4.2% and infection in 3.2%. The duration of PNC placement was a risk factor (P < 0.05). Surgical intervention was necessary in 0.9%. No late complications occurred in any patient. Interscalene catheters were associated with an increased risk of infection (4.3%; P < 0.05). Anterior proximal sciatic catheters were associated with a lower risk of local inflammation (1.7%; P < 0.05) and infection (0.4%; P < 0.05). Staphylococcus epidermidis and Staphylococcus aureus were isolated in 42% and 58% of catheter tip cultures, respectively.

CONCLUSION

In the present study population, infection of PNCs was a rare occurrence, but the incidence increased with the duration of PNC placement, and close clinical monitoring is required.

Komplikationen bei peripherer Katheterregionalanästhesie

INTRODUCTION

Over a period of 36 months we prospectively documented infectious, neurological and other complications or adverse events occurring during 3,491 peripheral regional anesthesias via a catheter using computer-based data recording.

METHODS

The investigation included 936 axillar plexus catheters, 473 interscalene plexus catheters, 125 vertical infraclavicular plexus catheters, 74 catheters with psoas compartment blocks, 900 femoral nerve catheters, 964 sciatic nerve catheters and 19 catheters in other localizations. The regional anesthesia catheters were inserted under sterile circumstances (hood, facemask, sterile gloves and coat, surgical disinfection and sterile covering of the placement site) and under peripheral nerve stimulation.

RESULTS

3,070 (87.9%) of the regional anesthesias via catheter, were carried out without any complications. Inflammation (two out of three criteria: redness at insertion site, pain on palpation or swelling) was found in 146 patients (4.2% of all cases). Infections (two out of the criteria: CRP elevation, pus on the insertion site, fever, leucocytosis, necessary antibiotic treatment with exclusion of other possible causes) appeared in 2.4% of all cases (83 patients). In 29 patients (0.8%) we observed severe infections (surgical intervention necessary e.g. abscess incision). Risk factors for inflammation or infections included duration of catheter therapy, cervical localization of the catheter and the experience of the anesthesiologist (p<0.05). Bacterial species most frequently found were Staphylococcus aureus (54%) and Staphylococcus epidermidis (38%). In 0.3% (9 patients) we found short lasting neurological deficits and in 6 patients (0.2%) we recorded a nerve lesion that lasted more than 6 weeks. Other complications occurred in 4.2% of all cases.

DISCUSSION

Special complications such as infections in peripheral catheter regional anesthesia are rare but can pose severe problems. A close postoperative supervision of all regional catheters has to be ensured under careful consideration of the risk factors for infections and the accompanying symptoms.

Laterale Ischiadikusblockaden

In the present study we examined 41 volunteers using magnetic resonance imaging to obtain biometric data of the thigh used for a planned blockade of the sciatic nerve via the lateral approach. At a needle entry point 12 cm proximal to the gap of the knee joint at the posterior border of the M. vastus lateralis, the sciatic nerve lies on average at a depth of 5.2 cm (39% of the femoral diameter at this site) with an angle of 10.9 degrees to the horizontal in a dorsal direction. Here the popliteal artery lies on average at a depth of 6.4 cm (48% of the femoral diameter) with an angle of 4.7 degrees to the horizontal in a ventral direction. At the marked point in the middle between the gap of the knee joint and the trochanter major at the posterior border of the M. vastus lateralis, the sciatic nerve is at an average depth of 6.2 cm (40% of the femoral diameter at this site) with an angle of 8.2 degrees in a dorsal direction. At a marked point 5 cm distal of the trochanter major at the posterior border of the M. vastus lateralis, the sciatic nerve is at a depth of 9.1 cm at a dorsal angle of 15.5 degrees (49% of the femoral diameter). The lateral blockade of the sciatic nerve at different sites of the thigh is a technique which is easy to plan with the presented biometric data. The popliteal artery could be reached only at the distal puncture point using a deep puncture and an angle in the ventral direction.

Einfluss der Blockade mit Lokalanästhetika auf die Stimulierbarkeit eines Nerven mit der peripheren Nervenstimulation

In the present study we examined the influence of local anesthetics on the ability to stimulate a nerve by means of peripheral nerve stimulation. In 35 patients either 5 ml saline (group 1, n=18) or local anesthetics (group 2, n=17) were injected close to the sciatic nerve in a randomized and double-blind manner. The current needed to stimulate the nerve was measured 30 s and 2 min after injection. The results showed that 30 s and 2 min after injection of local anesthetics there is a strong local anesthetic effect. Therefore nerve damage might occur despite the use of peripheral nerve stimulation. Thus, the multiple injection technique in a close anatomical area has to be considered critically, because anesthetized or partially anesthetized nerves have a lower stimulating ability and could be damaged by a second or third puncture.

Psoasabszess bei Psoaskompartmentkatheter

A 27-year-old female patient was continuously treated with a psoas compartment catheter for pain therapy. The catheter was placed under strictly aseptic conditions. After 5 days a painful swelling and erythema were observed at the catheter introduction site and the catheter was removed. At the tip of the catheter a staphylococcus aureus infection was detected. A few days after removing the catheter, the patient showed signs of a general infection such as fever and an increase of CRP. An abscess of the psoas muscle was diagnosed via computer tomography. After treatment with antibiotics the abscess was healed and the patient was discharged after 21 days. An abscess of the psoas muscle is a rare complication of psoas compartment catheters. Erythema, pain or swelling at the site of introduction can be a sign of infection and the catheter must be removed immediately. In addition to the case report a review of the literature is given with data on risk management and own infection rates by 2304 peripheral pain catheters.

Pharmacokinetics and efficacy of 40 ml ropivacaine 7.5 mg/ml (300 mg), for axillary brachial plexus block--an open pilot study

In this study, the pharmacokinetics, tolerability and efficacy of 40 ml of ropivacaine 7.5 mg/ml (300 mg) for axillary brachial plexus block were investigated. With institutional review board approval, 10 patients presenting for surgery of the upper limb were enrolled in this open study. The axillary plexus was identified with a nerve stimulator and the study drug was injected into the neurovascular sheath. Fifteen venous blood samples were obtained from each patient for pharmacokinetic measurements over a 24-h period. All blocks were sufficient for surgery after 45 min without any need for supplemental analgesia or general anesthesia. The mean (SD) peak plasma concentration was 2.3 (0.8) mg/l at median tmax 54 min (range 16-92 min). The mean (SD) maximum free plasma concentration was calculated to be 0.12 (0.06) mg/l (range 0.07-0.29 mg/l). The t 1/2 was about 6 h. There were no clinical signs or symptoms of central nervous system and/or cardiac toxicity in any patient. Ropivacaine 7.5 mg/ml, used in a dose of 300 mg, was effective and well tolerated for axillary brachial plexus block.

Mutation analysis of replicative genes encoding the large subunits of DNA polymerase alpha and replication factors A and C in human sporadic colorectal cancers

We examined cDNAs of the catalytic subunit of DNA polymerase alpha (185 kDa), the 70 kDa subunit of replication protein A (single-stranded DNA-binding protein) and the 140 kDa subunit of replication factor C for mutations. Surgical specimens from 12 patients with sporadic colon cancer and normal mucosae from the same patients were investigated. In addition, we analyzed 3 human colon cancer cell lines that exhibited defects in mismatch repair (DLD-1, HCT116, SW48) and 3 colon cancer cell lines without such a defect (HT29, SW480 and SW620). For detection of mutations, we used reverse transcription of mRNA, amplification of cDNAs by PCR, analysis of single-strand conformation polymorphism and DNA sequencing. Eleven colon cancers and 6 colon cancer cell lines were analyzed for DNA polymerase alpha. Only 2 silent point mutations were detected, in 1 colon carcinoma and in cell line HCT116. Two sequence alterations of the 70 kDa subunit of replication factor A were identified in 15 specimens (9 colon carcinomas and 6 cell lines). Colon carcinomas from 2 patients (CC5MA and CC25HN) exhibited an ACA-->GCA transition in codon 351, which caused a Thr-->Ala exchange. In carcinomas CC5MA and CC8MA, a TCC-->TCT (Ser-->Ser) transition in codon 352 was observed. The deviations in codons 351 and 352 occurred in both cancer tissues and normal mucosae, suggesting a genetic polymorphism. No mutation was found in the 140 kDa subunit of replication factor C from 16 specimens (10 tumors and 6 cell lines). Point mutations were identified in the p53 tumor-suppressor gene in 4 of the 6 colon cancer cell lines and 3 of the 8 carcinoma specimens. We did not find tumor-associated DNA sequence alterations that resulted in amino acid changes in the DNA replication genes analyzed. We infer that the scarcity of mutations found is due to stringent selection, eliminating functionally impaired replication proteins.

Effect of cholestyramine on bile acid pattern and synthesis during administration of ursodeoxycholic acid in man

BACKGROUND

Cholestyramine is the first-line treatment for cholestasis-induced pruritus and is prescribed along with ursodeoxycholic acid (UDCA) in patients with cholestatic liver diseases. Impairment of the intestinal absorption of endogenous hydrophobic bile acids by cholestyramine is well known. It is unclear, however, whether cholestyramine also impairs the absorption of the hydrophilic bile acid, UDCA, in man.

AIMS

To study serum levels of UDCA and endogenous bile acids as well as endogenous bile acid synthesis during simultaneous or separate administration of UDCA and cholestyramine in vivo; and absorption of UDCA both in the presence and absence of its hydrophobic epimer, chenodeoxycholic acid (CDCA), by cholestyramine in vitro.

PATIENTS AND METHODS

Five healthy subjects received UDCA (12.5 +/- 0.5 mg kg-1 daily) as a single dose for periods of 14 days with or without cholestyramine (4 g daily). Fasting serum levels of bile acids and of 7alpha-hydroxy-4-cholesten-3-one (alpha-HC), a measure of endogenous bile acid synthesis, were determined by gas chromatography and high pressure liquid chromatography, respectively. In vitro, bile acid solutions were incubated for 24 h in the presence or absence of cholestyramine, and bile acid concentrations were determined in the supernatant.

RESULTS

Simultaneous administration of UDCA and cholestyramine in man led to a decrease of fasting serum levels of UDCA by 60% when compared to UDCA serum levels during administration of UDCA alone. In contrast, serum levels of endogenous bile acids were not affected and alpha-HC serum levels were found increased 2. 7-fold indicating stimulation of endogenous bile acid synthesis by cholestyramine. Administration of cholestyramine and UDCA at an interval of 5 h tended to diminish the effect of cholestyramine on UDCA serum levels. In vitro, conjugated and unconjugated UDCA were effectively bound by cholestyramine both in the presence and absence of hydrophobic bile acids.

CONCLUSIONS

The results strongly support the recommendation to administer UDCA and cholestyramine at different times of day.

Impacts of laboratory methodology on medical thinking in the 19th century

During the 19th century the first laboratories at hospitals and clinics in Central Europe were established. These 'clinical laboratories' were devoted to chemical analyses in practical medicine and clinical research. A characteristic feature of these laboratories was the use of measuring instruments, e.g. volumetric apparatus, polarimeters, spectroscopes, colorimeters, photometers. Using these techniques new phenomena were introduced into clinical medicine which could serve as signs in the diagnosis of diseases. Many of the new diagnostic signs were quantitative data as results of measurements. Their main advantage was the greater differentiation in the description of phenomena compared with the qualitative data used before. Another important characteristic of the new diagnostic signs was the discovery of causal relations to physiological and pathological processes in the organism. The physicians and chemists in the clinical laboratory were eager not only to collect empirical data but also to find causal relationships by research work similar to that carried out in physics and chemistry. Once causal chains were been identified more general relationships became clear. One example is the concept of metabolism which comprised a dynamic view on chemical processes in the body and the variation of "Stoff" (material) in time, including a quantitative input-output analysis of the body in health and disease. In the second half of the 19th century, scientifically based diagnostic signs began to replace the traditional symptoms and signs used since antiquity.

Lipopeptides as dimerization inhibitors of HIV-1 protease

In AIDS therapy, attempts have been made to inhibit the virus-encoded enzymes, e.g. HIV-1 protease, using active site-directed inhibitors. This approach is questionable, however, due to virus mutations and the high toxicity of the drugs. An alternative method to inhibit the dimeric HIV protease is the targeting of the interface region of the protease subunits in order to prevent subunit dimerization and enzyme activity. This approach should be less prone to inactivation by mutation. A list of improved 'dimerization inhibitors' of HIV-1 protease is presented. The main structural features are a short 'interface' peptide segment, including non-natural amino acids, and an aliphatic N-terminal blocking group. The high inhibitory power of some of the lipopeptides [e.g. palmitoyl-Tyr-Glu-Leu-OH, palmitoyl-Tyr-Glu-(L-thyronine)-OH, palmitoyl-Tyr-Glu-(L-biphenyl-alanine)-OH] with low nanomolar Ki values in the enzyme test suggests that mimetics with good bio-availability can be derived for AIDS therapy.

Detection of mutations in the DNA polymerase delta gene of human sporadic colorectal cancers and colon cancer cell lines

To test the hypothesis whether DNA polymerases acquire mutator properties during tumor development (mutator hypothesis), we examined DNA polymerase delta mRNA in 6 colon cancer cell lines (DLD-1, HCT116, SW48, HT29, SW480 and SW620) and 7 sporadic human colorectal cancers. For analysis we used amplification of cDNA by polymerase chain reaction, single-strand conformation polymorphism and sequencing techniques. In 5 of the cell lines, 9 mutations leading to changes of the amino acid sequence of DNA polymerase delta were detected. Most mutations were found in the cell lines DLD-1, HCT116 and SW48 for which defects in mismatch repair genes had been identified previously. In the majority of cases, wild type and mutated sequences were present. In 2 cell lines (HCT116 and SW48), a single-nucleotide deletion occurred at the same position. This resulted in a premature termination codon by which the DNA interaction domain of the enzyme was eliminated. Furthermore, sequence deviations were found in the tumor tissues of 4 colon cancer patients. Wild-type and altered sequences were present simultaneously. The deviations included missense mutations (2 cases) and silent mutations (2 cases). The missense mutations and one of the silent mutations were found in normal mucosa as well. In addition, the mutation clustered region of a tumor suppressor gene, often found to be defective in colon cancer, the adenomatous polyposis coli (APC) gene, was investigated in surgical specimens and cell lines. One carcinoma and 2 cell lines exhibited amino acid changes in both the DNA polymerase delta gene and in the mutation clustered region of the APC gene. Since most of the mutations detected in the DNA polymerase delta mRNA are likely to alter the structure of the protein, the enzyme is expected to be functionally impaired. In particular, copying fidelity might be decreased, thus contributing to the high mutation rate observed in colorectal cancer.

Axillary and midhumeral approach for plexus block

Many variations of the axillary approach for blocking of the brachial plexus have been described. The axillary approach tends to be the technique with the lowest risk of serious complications; in particular, there is no risk of pneumothorax. A fairly high failure rate and an onset time of 20-40 minutes is why this technique, first described by Hirschel in 1911, is still discussed. Ideally, axillary brachial plexus blockade would be achieved using a technique that was easy and quick to perform with a fast onset time, a 100% success rate and without any risk for the patient; but, as all studies show, this goal is still far away.

Determination of pH in human erythrocytes. Sources of systematic error

The results of a simultaneous determination of the pH value in erythrocytes with the potentiometric measuring method and the 14C-labelled 5,5-dimethyl-2,4-oxazolidinedione (DMO) method showed a mean method difference of 0.026 pH units. The cause of this discrepancy was assumed to be matrix-inherent liquid-junction potentials in the potentiometric measurement. Taking these into account in the calculation leads to consistent values for the methods investigated. The DMO method proved to be free of systematic errors. Another indication of this is that its mean ratio of extracellular to intracellular H+ ion concentration (H+e/H+i) substantially agreed with the distribution ratios of other freely diffusible ions and their pH dependence.

Biological variation and quantification of health: the emergence of the concept of normality

Historical research on the concept of normality, its roots and its development show that this concept has its sources in very different areas of scientific and medical thinking. Of great importance were: (i) a new theory of disease arising early in the 19th century supposing a continuous change from the healthy to the diseased state; (ii) the examination of variation within and between species of plants and animals; (iii) the clinical theory of constitution developed to describe the wholeness of the individual determined both by genetic factors and the influence of the environment; (iv) the development of mathematical and statistical tools starting with the adaptation of Bernoulli's "law of the great numbers" and Gauss' and Legendre's "law of errors" to biological measurements by the Belgian astronomer Quetelet. At the end of the First World War the concept of normality was first discussed. An idealistic "value norm" was set against a statistical "frequency norm". Between 1920 and 1930 the principles of our present concept were accepted and the mathematical tools developed. It took several decades to introduce this concept into practical medicine finally being recommended by the IFCC.

Clinical chemistry in laboratory medicine in Europe--past, present and future challenges

European experts in clinical laboratory sciences have different backgrounds, and development of expertise in this field started more than 100 years ago. Specific national activities have created the heterogeneity that now exists amongst the academic professional membership of more than 40 scientific societies in Europe. The recent political changes have in addition contributed to the rapidly changing profile of Clinical Chemistry and related fields. Based on a questionnaire answered by 31 national representatives, the past, present and future aspects of the European Clinical Laboratory are reviewed. Of the more than 30,000 members of national societies, the majority studied medicine (40.1%), chemistry (27.2%) and pharmacy (21.1%) with large national differences in relative percentages. Post-graduate education is provided by two thirds of the national societies. In most European countries the same experts cover not only clinical chemistry but also haematology, haemostaseology, immunology and transfusiology. National quality assurance programmes are said to be established in 25 countries, but mandatory in only 11 of them. Of the future challenges, the implementation of request strategies were named most often, with interpretative reports and preanalytical aspects estimated as similarly important. It was thought that information technology and new scientific developments would make the greatest impact in the coming years, with economic pressure being the major limiting factor. Despite these limitations an increase in the number of tests is anticipated by most representatives, supporting the assumption of an increasing role of the clinical laboratory in future clinical medicine.

Diagnostic validity as a theoretical concept and as a measurable quantity

The analytical result of a laboratory examination is a scientific fact and has no medical meaning as such. It must be interpreted to become a medical finding. To explain the very complex cognitive procedure of the interpretation a three-level model is used. In an environment of cost containment in health care systems the quality of medical laboratory findings is very important. Analytical results are monitored by quality control procedures. For measuring the performance of medical findings the concept of the 'validity' of a laboratory test is used. Validity means the 'degree of achieving the objective'. Accordingly, a valid laboratory finding is one which correctly answers the question which the physician at the sick-bed directs to the laboratory. Quantitative measures for the validity of interpretation can be developed by an analysis of the underlying classification processes. Characteristic indices describing the validity quantitatively in terms of conditional probabilities can be derived from decision tables. Examples of 'validity indices' are diagnostic (or prognostic) 'sensitivity' and 'specificity'. These indices are powerful tools for developing strategies for the clinical use of laboratory examinations in diagnosis, prognosis and therapy management. Moreover, validity indices are appropriate output quantities for the estimation of effectiveness and efficiency of a diagnostic or prognostic examination.

Screening of inhibitors of HIV-1 protease using an Escherichia coli cell assay

To evaluate the available peptidic and pseudopeptidic inhibitors of HIV protease for their possible in vivo activity, a screening test using Escherichia coli was established. E. coli cells carrying the plasmid pET9c-PR containing the gene for HIV-1 protease under the control of a T7-promotor are grown in the absence and in the presence of inhibitors. The action of the toxic protease produced by the cells is counteracted by the inhibitors. Provided sufficient membrane permeability of the inhibitors exists, this results in accelerated cell growth. From the peptides known to be active in an in-vitro enzyme test, most compounds inhibit HIV protease only to a limited degree in this test. However, two short peptides (Ac-Ser-Tyr-Glu-Leu and Lys-Ile-Ser-Tyr-Asp-Tyr) protect cell growth to an considerabe extent, thus indicating that they reach the E. coli cytosol and there block HIV protease. Two pseudopeptides known to be very potent in the enzyme test (SDZ PRI 053 and CIBA 61755) also inhibit HIV-1 protease strongly in this cell growth test.

[Fulminant air embolism in arthroscopy of the shoulder joint using CO2]

We report on a case of an unexpected gas embolism during an arthroscopy of a newly injured shoulder joint. We used carbon dioxide as an arthroscopic medium which has not been considered hazardous up to now. The sudden decrease of the endtidal CO2 concentration in connection with a decrease of peripheral oxygen saturation as well as the clinical symptoms led to an immediate diagnosis of gas embolism. In this case external cardiac massage and aspiration of gas from the right ventricle proved an effective treatment.