The epidemiology and burden of gastroparesis: Real-world data from a large healthcare provider in Israel

BACKGROUND

Gastroparesis is a gastrointestinal motility dysfunction characterized by delayed gastric emptying in the absence of gastric mechanical obstruction. Data on the epidemiology of gastroparesis are sparse even though the condition substantially impairs patients' quality of life. The aim of this study was to describe the epidemiology and estimate the short-term healthcare resource use burden of gastroparesis in a large population.

METHODS

This cross-sectional study utilized computerized data from Maccabi Healthcare Services, a 2.5-million member state-mandated health organization in Israel. Data were collected between 2003 and 2018 to assess the prevalence of gastroparesis. Definite gastroparesis was defined by gastroparesis diagnosis and gastric emptying test. Probable gastroparesis was defined by gastroparesis diagnosis only. To compare the healthcare resource utilization (HCRU), data were also collected on controls that were individually matched (1:2) for age, sex, and comorbidities.

KEY RESULTS

A total of 522 patients with gastroparesis were identified (21.1 per 100,000 WHO age-standardized), including 204 with definite gastroparesis (8.6 per 100,000 WHO). Male to female ratio was 1:2 and mean ± SD age of 54.7 ± 17.1 years. Diabetes accounted for 25.9% of gastroparesis cases and the rest were idiopathic. Gastroparesis patients were more likely to have cardiovascular diseases (10% vs. 6.9% for controls, p = 0.034) and lower prevalence of obesity (17% vs. 24.4%, p < 0.001). HCRU within the 2 years after index date were higher with more hospitalizations than controls (26.4% vs. 15.4%, p < 0.001), and more emergency room visits (31.6% vs. 24.1%, p = 0.002).

CONCLUSIONS & INFERENCES

Gastroparesis is uncommon or under-documented in community care settings. Gastroparesis in general is associated with cardiovascular morbidities, lower BMI, and elevated utilization of healthcare services.

Inflammatory Bowel Disease Patients' Treatment Preferences Using a Discrete Choice Experiment Technique: The InPuT Study

Introduction

The aim of this study was to investigate patients’ preferences regarding the evolving treatment landscape in Crohn’s disease (CD) and ulcerative colitis (UC) based on a discrete choice experiment.

Methods

Eligible patients (aged 18 years or older) had a confirmed diagnosis of CD or UC and were willing and able to participate in telephone interviews. The survey design is based on a prior literature review, a pilot study, and clinical expert discussions. Preferences related to clinical and practical features of advanced therapies, like tumor necrosis factor alpha inhibitors, anti-integrins, anti-interleukins, and Janus kinase inhibitors, were assessed. Patients were asked to choose between two different hypothetical treatment alternatives visualized in up to 11 choice scenarios. Based on these choices, the relative importance of treatment characteristics was derived from regression coefficients estimated by a conditional logit model.

Results

Of the 291 patients included, 219 (75%) were eligible for this analysis. Among the evaluated attributes in CD, 1-year remission rate was ranked highest, with 42.3% relevance for the overall decision. The second most important attribute was the frequency of serious adverse events (AE) (25.1%), followed by sustained remission over 2 years (17.8%). Lower importance was assigned to the administration mode (14.6%) and none to the frequency of non-serious AE (0.1%). In UC, preferences were driven by efficacy (25.3% for mucosal healing; 23.4% for corticosteroid-free remission) and the frequency of serious AE (18.3%), followed by the administration mode (18.1%). Also, non-serious AE were classified as relevant factors for decision-making (10.7%), while maintaining remission for at least 2 years showed no significant impact (4.4%).

Conclusion

For both indications, efficacy outcomes were rated most important, followed by the frequency of serious AE. Variations were mainly found in the evaluation of non-serious AE and sustained remission. Considering patient preferences may improve the effectiveness of available therapies for moderate to severe CD and UC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-022-02143-z.

Cytomegalovirus infection and rehospitalization rates after allogeneic hematopoietic stem cell and solid organ transplantation: a retrospective cohort study using German claims data

PURPOSE

This study aimed to describe the cytomegalovirus (CMV) infection rate, rehospitalizations, and comorbidities following allogeneic hematopoietic stem cell transplantation (allo-HSCT) and solid organ transplantation (SOT).

METHODS

Patients who received allo-HSCT or SOT in 01/07/2015-30/06/2018 were identified using anonymized German claims data. The transplantation-related hospital admission date was defined as the index date, and patients were followed for up to 12 months (or death, first event relevant). The frequency of CMV infections (confirmed outpatient/inpatient diagnoses, ICD-10-GM codes: B25.-/B27.1) and the rate, number, and duration of all-cause rehospitalizations in the follow-up period were evaluated.

RESULTS

A total of 226 allo-HSCT and 250 SOT patients were identified (mean age 52.8 years, 38.9% female). During the 12 months after transplantation, 29.2% of allo-HSCT patients and 16.8% of SOT patients received a CMV diagnosis. The majority of these diagnoses were given during the initial hospitalization or within the following 3 months. Across transplantation types, CMV patients had more hospital readmission days per patient-year (allo-HSCT 93.3 vs. 49.4, p = 0.001; SOT 42.0 vs. 20.7, p = 0.005), with a longer mean duration of readmissions (allo-HSCT 22.4 vs. 15.4 days, p < 0.001; SOT 11.6 vs. 7.5 days, p = 0.003). Comorbidity burden in transplantation patients was substantial, with several diagnoses being significantly more common among patients with CMV vs. non-CMV. One-year mortality did not differ significantly between patients with/without CMV.

CONCLUSION

Burden of transplant recipients with CMV in terms of rehospitalizations and comorbidities is substantial, highlighting the need for improved CMV prevention and treatment.

Novel Approaches Identifying Relevant Patient-Reported Outcomes in Patients With Inflammatory Bowel Diseases-LISTEN 1

Background

Several patient-reported outcomes (PROs) have been established and are widely used in the assessment of patients with inflammatory bowel disease (IBD). However, it has never been investigated which PRO items are experienced by and are considered most relevant for IBD patients.

Methods

A review of IBD-related disease scores by a steering committee led to the identification of relevant PRO questions and assignment to 16 different PRO categories (9 symptoms and 7 impacts) that characterize patient's disease burden. In a cross-sectional study, a digital patient survey was carried out to determine the self-reported experience by multiple response, the relevance of these PRO categories by pairwise comparison and the suitability of the respective questions and answer possibilities by yes-or-no-question.

Results

Sixty patients with Crohn's disease (CD) (56.7% women; mean age 40.6 years; mean disease duration 12.4 years) and 60 patients with ulcerative colitis (UC) (51.7% women; mean age 37.3 years; mean disease duration 9.0 years) participated in the patient survey. All predefined symptoms and impacts, with the exception of nausea, were experienced by at least 50% of patients. Stool urgency and pain were rated the 2 most important symptoms in CD patients with similar ratings for relevance. Stool urgency was also the most important symptom in patients with UC, followed by stool frequency. Differences in self-reported experience between CD and UC patients were seen for the symptoms of rectal bleeding, pain, and nausea. Most important impact of symptoms in both patient groups were general wellbeing followed by social activities, while sexual activity was the least relevant impact category.

Conclusions

Stool urgency was the most relevant and most self-reported symptom for both CD and UC. Relevance and self-reported experience of pain and rectal bleeding differed between the 2 diseases. Therefore, the future collection of PROs should take these disease specificities into consideration.

Safety of vedolizumab in the treatment of pregnant women with inflammatory bowel disease: a targeted literature review

BACKGROUND

Crohn's disease (CD) and ulcerative colitis (UC) commonly affect women in their childbearing years. Vedolizumab (VDZ) is approved for treatment of moderate-to-severe CD and UC, but there is a knowledge gap regarding its use during pregnancy. This targeted literature review describes available evidence on safety of VDZ in pregnant patients in order to offer physicians a detailed and balanced view on persistent data during their decision-making process for an individualized treatment concept.

METHODS

The search included literature from the MEDLINE database and abstracts of five gastroenterological conferences published until November 2019. Publications were included if pregnancy outcomes in women receiving VDZ or neonatal outcomes in newborns of women previously exposed to VDZ were reported.

RESULTS

Out of 196 initially identified records, 18 publications reporting results of five different studies were identified. In total, for 213 of 284 VDZ-exposed documented pregnancies the following pregnancy outcomes were reported: 167 live births (172 infants due to twin births), 1 stillbirth, 35 miscarriages, 10 elective terminations (1 due to detected Down syndrome). Furthermore, during pregnancy, the following complications were observed: seven cases of (pre) eclampsia, three cases of premature rupture of membranes and one case each of placenta previa, chorioamnionitis, pneumonia, first-trimester bleeding, cholestasis, sepsis, or neonatal intraventricular hemorrhage. Based on 172 infants, 30 preterm deliveries (17.4%), 9 cases of low birth weight (5.2%), 5 infections (2.9%), and 6 cases (3.8%) with congenital anomalies were reported.

CONCLUSION

There was no evidence for safety concerns regarding pregnancy outcomes associated with VDZ therapy. Due to the limited scope of included records, further research is needed to understand the safety profile regarding the use of VDZ during pregnancy.

Indicators of active disease and steroid dependency in patients with inflammatory bowel diseases not treated with biologics in a German real-world-setting

BACKGROUND AND AIMS

While a minority of inflammatory bowel disease (IBD) patients receives biologics in Germany, little is known about therapeutic needs of patients receiving non-biologic therapies. This study aimed to identify indicators of active disease/steroid dependency in patients with moderate to severe Crohn's disease (CD) and ulcerative colitis (UC) treated with conventional therapies and to describe health care resource use (HCRU)/cost.

METHODS

CD/UC patients treated with immunosuppressants (IS) and/or systemic or locally acting oral corticosteroids (CS) were identified in German claims data (2013-2017) and followed for 12 months post-therapy start. Indicators of active disease/steroid dependency during follow-up period were (i) ≥ 2 prescriptions of CS (sensitivity ≥ 4) or (ii) ≥ 1 IBD-related surgery or (iii) > 7 days IBD-related hospitalization(s).

RESULTS

Of 9871 included IBD patients (5170 CD, 4701 UC), 25.7%/19.9% (CD/UC) received ≥ 2 prescriptions of CS (sensitivity, 17.4%/15.7%) (i), 3.2% experienced IBD-related surgeries (ii), and 2.5% > 7 days of hospitalizations (iii). Altogether, 44.4% had indicators of active disease/steroid dependency (sensitivity, 23.9%). Among patients with active disease/steroid dependency, 78.0% received CS monotherapy at baseline. Of these, 89.6% received a CS monotherapy in the follow-up period, too. Proportionally, fewer patients with CS monotherapy (57.4%) than IS therapy (91.0%) visited a specialist. HCRU/cost per patient year was significantly higher in patients with than without active disease/steroid dependency.

CONCLUSIONS

A substantial percentage of biologic-naïve IBD patients suffers from active disease/steroid dependency. The majority receives a monotherapy with systemic CS. Referral to gastroenterologists for treatment optimization is recommended, also because active disease/steroid dependency is associated with increased HCRU/cost.

Real-world clinical effectiveness and safety of vedolizumab and anti-tumor necrosis factor alpha treatment in ulcerative colitis and Crohn's disease patients: a German retrospective chart review

Background

Real-world comparisons of biologic treatment outcomes for ulcerative colitis (UC) or Crohn’s disease (CD) patients are limited. We sought to evaluate the real-world effectiveness of vedolizumab (VDZ) and anti-tumor necrosis factor alpha (anti-TNFα) in UC and CD patients in Germany.

Methods

A retrospective chart review (15 sites) investigated UC and CD patients who were biologic-treatment naïve (biologic-naïve) or had received no more than one prior anti-TNFα before initiating treatment with VDZ or anti-TNFα between 15 July 2014 and 20 October 2015. Kaplan-Meier analyses assessed time to first chart-documented clinical remission (CR) and symptom resolution (UC: rectal bleeding [RB], stool frequency [SF]; CD: abdominal pain [AP], liquid stools [LS]) and outcome duration.

Results

A total of 133 UC (76 VDZ; 57 anti-TNFα) and 174 CD (69 VDZ; 105 anti-TNFα) patients were included. By Week 26, estimated cumulative rates of patients achieving CR or symptom resolution with VDZ vs anti-TNFα treatment were for UC: CR, 53.7% vs 31.7%; RB, 66.8% vs 55.8%; and SF, 59.8% vs 50.7%, respectively; and for CD: CR, 14.4% vs 32.8%; AP, 62.5% vs 56.0%; and LS, 29.9% vs 50.3%, respectively. Outcomes were sustained similarly between treatments, except RB (VDZ vs anti-TNFα: median 38.1 vs 15.1 weeks, P = 0.03). Treatment-related adverse events occurred in 5.3% vs 7.0% (UC) and 8.7% vs 19.0% (CD) of VDZ vs anti-TNFα patients, respectively.

Conclusions

Although there were differences in CR, symptom resolution, and safety profiles, real-world data support both VDZ and anti-TNFα as effective treatment options in UC and CD.

Alcohol and delirium tremens: effects of average number of drinks per day and beverage type

OBJECTIVE

Associations of amount of alcohol intake and beverage type with the risk of delirium tremens (DT) have not been studied. This longitudinal study investigated if the average number of drinks per day and beverage type predict DT.

METHODS

A cohort of 3 582 alcohol-dependent men and women aged 19-82 without previous DT were interviewed about alcohol intake and beverage type at baseline in 1994-2005 and followed through record linkage in Danish nationwide registers to identify incident DT. Data were analyzed by means of Cox regression models.

RESULTS

An average number of drinks per day of 20-30 or >30 was associated with hazard ratios (HRs) of 1.38 (95% CI 1.03-1.84) and 1.64 (95% CI 1.19-2.27) relative to the reference category (1-9 drinks). Independently of amount consumed and covariates (age, gender, civil status and work status), beverage type (spirits vs. mixed alcohol) was associated with a HR of 1.63 (95% CI 1.08-2.46). Male gender was robustly associated with increased risk (HR = 1.62 (95% CI 1.25-2.08).

CONCLUSIONS

In alcohol-dependent men and women, daily alcohol intake above a threshold of 20 beverages or 240 g alcohol and a preference for spirits increase the risk of developing DT.

Szintigraphische Verlaufskontrolle von Osteosarkomen während neoadjuvanter Chemotherapie

The response of osteosarcomas to preoperative chemotherapy as measured by quantitative 99mTc-diphosphonate scintigraphy was compared with the amount of tumor cell destruction found histologically in the resected specimens. 3-phase bone scintigraphy, with determination of tumor/non-tumor (T/NT) ratios, allowed accurate prediction of tumor response in 28 of 30 tumors (accuracy = 93%) after completion and in 10 of 12 osteosarcomas (83%) at the half-way stage of preoperative chemotherapy, when only those tumors were evaluated which showed convergent changes of T/NT ratios in the perfusion and the mineral phase. At the half-way stage, however, evaluation of chemotherapy effects was complicated in 12 of 23 osteosarcomas by diverging T/NT ratios. In contrast, quantification and mapping of the tumor plasma volume and 99mTc-diphosphonate clearance on parametric images predicted correctly the histological tumor response to chemotherapy in 10 of 11 tumors (91%) after completion and in all 11 cases (100%) at the half-way stage.

Funktionsszintigraphie: Eine einheitliche Methode zur Quantifizierung von Stoffwechsel und Funktion in Organen

Die Funktionsszintigraphie ist eine quantitative Methode, mit welcher Stoffwechselgrößen eines Organs durch die Messung des zeitlichen Aktivitätsverlaufs eines Tracers im Gewebe bestimmt werden können. Ihre quantitative Aussage wird jedoch durch inhärente Fehlerquellen wie Absorption der Strahlung im Organ und Überlagerung von Vorder- und Hintergrundaktivität eingeschränkt. Bisherige Verfahren zur Berechnung von Funktionsparametern orientierten sich mehr an den gegebenen technischen Möglichkeiten als an gemeinsamen theoretischen Grundlagen. Sie fallen durch Vielfalt in ihren methodischen Ansätzen mit oft empirischem Charakter auf. Quantitative Ergebnisse verschiedener Institute und Kliniken sind deshalb selten vergleichbar. In der vorliegenden Arbeit wird ein methodischer Ansatz zur Vereinheitli-chung nuklearmedizinischer Auswertemethoden beschrieben. Grundlage ist die Einbeziehung der Pharmakokinetik eines Tracers im Blut. Dies führt zur Compartmentanalyse (deterministischen) oder zur stochastischen (nicht deterministischen) Beschreibung der kinetischen Vorgänge im Organ. Die stochastische Beschreibung setzt die Berechnung der Linear-Response-Funktion aus einem Fal-tungsintegral voraus. Mit Hilfe funktionalanalytischer Methoden wurde ein mathematisches Verfahren entwickelt, das es erlaubt, die Linear-Response-Funktion erstmals in jedem Bildpunkt und zu jedem Zeitpunkt zu berechnen. An einfach lesbaren Funktionsbildern wird gezeigt, wie relevante Parameter aus dem Funktionsverlauf der Linear-Response-Funktion berechnet werden können. Da diese Funktion modellunabhängig ist, ergibt sich die Möglichkeit, bestehende oder neue Modellvorstellungen der Tracer-kinetik im betreffenden Organ auch regional zuüberprüfen.

Implantation eines bovinen Venenklappen- Xenografts in die Vena femoralis communis bei Patienten mit postthrombotischem Syndrom

Ziel: Für Patienten mit Ulcus cruris bei postthrombotischem Syndrom (PTS) fehlen allgemein zugängliche, kausale Therapieverfahren. Mit einer Machbarkeitsstudie sollte für Patienten mit schwerer Refluxkrankheit die Implantation eines bovinen Einsegel-Venenklappen- Xenografts in die Vena femoralis communis (VFC) geprüft werden. Methoden: Bei 5 Patienten wurde das Implantat nach ventraler Resektion von ca. 70% der VFC so eingenäht, dass im Valsalva-Versuch Suffizienz bestand. Ergebnisse: Der Verlauf war komplikatonslos bei 2 Patienten, duplexsonographisch zeigte sich bei 2 Patienten ein von der Nahtstelle ausgehender, symptomloser Appositionsthrombus, in einem Fall kam es zur vollständigen thrombotischen Obstruktion der VFC. Keine der implantierten Klappen war nach 18 Monaten vollständig kompetent. Dennoch reduzierte sich der mittlere Knöchelumfang von 234 ± 13,9 mm präoperativ auf 215 ± 20,4 mm 18 Monate postoperativ. Die mittlere Ulkusfläche ging von 8,1 ± 10,3 cm2 auf 1,8 ± 2,1 cm2, der mittlere Durchmesser der Vena poplitea von 6,9 ± 2,0 mm auf 5,5 ± 0,5 mm zurück. Die apparativ ausgelösten Refluxvolumina im Bereich der V. poplitea verringerten sich von 380 ± 325 ml/min auf 191 ± 158 ml/min. Schlussfolgerung: Die Implantation eines bovinen Einsegel- Venenklappen-Xenografts in die VFC ist technisch möglich. Für den Einsatz in der klinischen Routine sind weitere Entwicklungen nötig.

The Nonmetabolized β-Blocker Nadolol Is a Substrate of OCT1, OCT2, MATE1, MATE2-K, and P-Glycoprotein, but Not of OATP1B1 and OATP1B3

Nadolol is a nonmetabolized β-adrenoceptor antagonist and is a substrate of OATP1A2, but not of OATP2B1. However, other drug transporters involved in translocation of nadolol have not been characterized in detail. We therefore investigated nadolol as a potential substrate of the hepatic uptake transporters OATP1B1, OATP1B3, and OCT1 and of the renal transporters OCT2, MATE1, and MATE2-K expressed in HEK cells. Moreover, the importance of P-glycoprotein (P-gp) for nadolol transport was studied using double transfected MDCK-OCT1-P-gp cells. Nadolol was not transported by OATP1B1 and OATP1B3. In contrast, a significantly higher nadolol accumulation (at 1 and 10 μM) was found in OCT1, OCT2, MATE1, and MATE2-K cells compared to control cells (P < 0.01). Km values for OCT2-, MATE1-, and MATE2-K-mediated nadolol uptake were 122, 531, and 372 μM, respectively. Cimetidine (100 μM, P < 0.01) and trimethoprim (100 μM, P < 0.001) significantly inhibited OCT1-, OCT2-, MATE1-, and MATE2-K-mediated nadolol transport. The P-gp inhibitor zosuquidar significantly reduced basal to apical nadolol transport in monolayers of MDCK-OCT1-P-gp cells. In summary, nadolol is a substrate of the cation transporters OCT1, OCT2, MATE1, MATE2-K, and of P-gp. These data will aid future in vivo studies on potential transporter-mediated drug-drug or drug-food interactions with involvement of nadolol.

Inhibitory Effects of Green Tea and (-)-Epigallocatechin Gallate on Transport by OATP1B1, OATP1B3, OCT1, OCT2, MATE1, MATE2-K and P-Glycoprotein

Green tea catechins inhibit the function of organic anion transporting polypeptides (OATPs) that mediate the uptake of a diverse group of drugs and endogenous compounds into cells. The present study was aimed at investigating the effect of green tea and its most abundant catechin epigallocatechin gallate (EGCG) on the transport activity of several drug transporters expressed in enterocytes, hepatocytes and renal proximal tubular cells such as OATPs, organic cation transporters (OCTs), multidrug and toxin extrusion proteins (MATEs), and P-glycoprotein (P-gp). Uptake of the typical substrates metformin for OCTs and MATEs and bromosulphophthalein (BSP) and atorvastatin for OATPs was measured in the absence and presence of a commercially available green tea and EGCG. Transcellular transport of digoxin, a typical substrate of P-gp, was measured over 4 hours in the absence and presence of green tea or EGCG in Caco-2 cell monolayers. OCT1-, OCT2-, MATE1- and MATE2-K-mediated metformin uptake was significantly reduced in the presence of green tea and EGCG (P < 0.05). BSP net uptake by OATP1B1 and OATP1B3 was inhibited by green tea [IC₅₀ 2.6% (v/v) and 0.39% (v/v), respectively]. Green tea also inhibited OATP1B1- and OATP1B3-mediated atorvastatin net uptake with IC₅₀ values of 1.9% (v/v) and 1.0% (v/v), respectively. Basolateral to apical transport of digoxin was significantly decreased in the presence of green tea and EGCG. These findings indicate that green tea and EGCG inhibit multiple drug transporters in vitro. Further studies are necessary to investigate the effects of green tea on prototoypical substrates of these transporters in humans, in particular on substrates of hepatic uptake transporters (e.g. statins) as well as on P-glycoprotein substrates.

Identification of PDGF-BB binding to thymosin β4 by chemical cross-linking

INTRODUCTION

The purpose of our work was to identify unknown interaction partners of thymosin β4 (Tβ4). It was suggested that Tβ4 could be an antifibrotic drug for treatment of liver fibrogenesis, because Tβ4 prevents the platelet-derived growth factor-BB (PDGF-BB)-induced activation of hepatic stellate cells (HSCs). Very little information is available how Tβ4 counteracts the PDGF-BB-induced activation of HSCs. We propose the hypothesis that Tβ4 could bind directly to PDGF-BB and thereby reduce the concentration of free PDGF-BB available for binding to the PDGF-β receptor.

METHODS

To prove our suggestion of a direct interaction between Tβ4 and PDGF-BB, we carried out chemical as well as photochemical cross-linking experiments between the two pure proteins in vitro.

RESULTS

We identified an interaction between Tβ4 and PDGF-BB by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) cross-linking as well as through biotin label transfer using a bifunctional photoactivatable derivative of Tβ4. In an in vitro system, PDGF-BB was identified as the first extracellular partner interacting with Tβ4. This interaction could influence PDGF-BB binding to its receptor and abolish PDGF-BB-related effects.

CONCLUSION

Direct interaction of Tβ4 with extracellular factors should be considered as a potential mechanism to explain the pleiotropic effects of β-thymosins.

Dipolmomente der Phenanthroline / Dipole-Moments of Phenanthrolines

Dipole moments of the ten isomeric phenanthrolines are presented and discussed shortly. They could be computed in a close approximation from the dipole moment vectors of the individual pyridine nuclei. Dipole moments calculated by means of the CNDO/2-method are in agreement with the experimental data.

Quantenchemische und spektroskopische Untersuchungen an Porphyrinen. IV. Die Bacteriochlorine / Quantum Chemical and Spectroscopical Studies on Porphyrins IV. The Bacteriochlorins

The Pariser-Parr-Pople Π-electron method, with the inclusion of all single excited configurations, has been used to predict the electronic transitions of bacteriochlorins.

High-resolution HPLC-ESI-MS characterization of the contact sites of the actin-thymosin β(4) complex by chemical and enzymatic cross-linking

Thymosin β4 sequesters actin by formation of a 1:1 complex. This transient binding in the complex was stabilized by formation of covalent bonds using the cross-linking agents 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and a microbial transglutaminase. The localization of cross-linking sites was determined after separating the products using SDS-PAGE by tryptic in-gel digestion and high-resolution HPLC-ESI-MS. Three cross-linked fragments were identified after chemical cross-linking, indicating three contact sites. Because the cross-linked fragments were detected simultaneously with the corresponding non-cross-linked fragments, the three contact sites were not formed in parallel. K3 of thymosin β4 was cross-linked to E167 of actin, K18 or K19 of thymosin β4 to one of the first three amino acids of actin (DDE), and S43 of thymosin β4 to H40 of actin. The imidazole ring of histidine was proven to be an acyl acceptor for carbodiimide-mediated cross-linking. Molecular modeling proved an extended conformation of thymosin β4 along the subdomains 1 to 3 of actin. The enzymatic cross-linking using a microbial transglutaminase led to the formation of three cross-linking sites. Q41 of actin was cross-linked to K19 of thymosin β4, and K61 of actin to Q39 of thymosin β4. The third cross-linking site was identified between Q41 of actin and Q39 of thymosin β4, which are simultaneously cross-linked to K16, K18, or K19 of thymosin β4. When both cross-linking reactions are taken together, the complex formation of actin by thymosin β4 is more likely to be flexible than rigid and is localized along the subdomains 1 to 3 of actin.

Antibodies in research of thymosin β4: investigation of cross-reactivity and influence of fixatives

Antibodies against thymosin β4 are available from various sources and have been used in immunohistochemistry, ELISA, and Western blot analyses. None of these antibodies have been fully characterized for specificity and influence of fixation techniques. This presents a difficulty because many tissues express more than one member of the β-thymosin family; in addition, highly homologous sequences are typical elements of β-thymosins. It is also important to scrutinize the influence of fixatives on the antibody-binding capability. Fixatives such as formaldehyde are well known as cross-linking reagents. Chemical modifications within the thymosin β4 molecule might change the putative epitope recognized by the antibody. These considerations suggest that investigations on thymosin β4 antibodies available to the scientific community are important and necessary before any experiment can be performed to exclude cross-reactivity with other β-thymosins that are coexistent in the examined tissue and to prove antibody binding after fixation steps.

Identification of interaction partners of β-thymosins: application of thymosin β4 labeled by transglutaminase

In this review, we identify potential interaction partners of the β-thymosin family. The proteins of this family are highly conserved peptides in mammals and yet only one intracellular (G-actin) and one cell-surface protein (β subunit of F(1) -F(0) ATP synthase) were identified as interaction partners of thymosin β4. Cross-linking experiments may be a possible approach to discover additional proteins that interact with the β-thymosin family. It has previously been shown that thymosin β4 can be labeled at its glutaminyl residues with various cadaverines using tissue transglutaminase. Here, we illuminate recent results and give an outlook on upcoming work in the field.

Role of ultrasound compared to age-related formulas for uncuffed endotracheal intubation in a pediatric population

BACKGROUND

It is often difficult to determine the correct size of endotracheal tubes (ETT) needed for intubating pediatric patients. Therefore, we evaluated the role of ultrasound in pediatric patients to compare the correct size of an uncuffed (ETT) with the minimal transverse diameter of the subglottic airway (MTDSA) measured by ultrasound and with tube size predicted by different age-related formulas.

METHODS

A total of 50 pediatric patients ≤ 5 years were enrolled. As a standard, we defined the adequate ETT size with no audible leakage below a ventilation pressure of 15 mbar and with an audible leakage above 25 mbar. The maximum allowed difference between the prediction method result and the ETT that fit was defined as 0.3 mm. Ultrasound was performed before the intubation procedure; the intubating anesthesiologists were blinded to the results of the ultrasound measurement. Agreement between the two age-based formulas most commonly used at our department and MTDSA with the correct ETT size (standard) was analyzed using a Bland-Altman plot. Correlation and regression analyses were performed and the numbers of correct intubation trials recorded.

RESULTS

The frequency of bias ≤ 0.3 mm between each method and the correct ETT in the first attempt was <50% and the mean number of reintubations 1.6 ± 1.3. In contrast to age-related formulas, however, the ultrasonographically determined MTDSA was not significantly different from the correct ETT. MTDSA was highly associated with the outer diameter of the ETT (r = 0.869, R(2) = 0.754).

CONCLUSIONS

Measuring MTDSA by ultrasound facilitates selection of the appropriate ETT in pediatric patients and may reduce the number of reintubations.