Genetic ablation of carbonic anhydrase IX disrupts gastric barrier function via claudin-18 downregulation and acid backflux

Aim

This study aimed to explore the molecular mechanisms for the parietal cell loss and fundic hyperplasia observed in gastric mucosa of mice lacking the carbonic anhydrase 9 (CAIX).

Methods

We assessed the ability of CAIX‐knockout and WT gastric surface epithelial cells to withstand a luminal acid load by measuring the pH_i of exteriorized gastric mucosa in vivo using two‐photon confocal laser scanning microscopy. Cytokines and claudin‐18A2 expression was analysed by RT‐PCR.

Results

CAIX‐knockout gastric surface epithelial cells showed significantly faster pH_i decline after luminal acid load compared to WT. Increased gastric mucosal IL‐1β and iNOS, but decreased claudin‐18A2 expression (which confer acid resistance) was observed shortly after weaning, prior to the loss of parietal and chief cells. At birth, neither inflammatory cytokines nor claudin‐18 expression were altered between CAIX and WT gastric mucosa. The gradual loss of acid secretory capacity was paralleled by an increase in serum gastrin, IL‐11 and foveolar hyperplasia. Mild chronic proton pump inhibition from the time of weaning did not prevent the claudin‐18 decrease nor the increase in inflammatory markers at 1 month of age, except for IL‐1β. However, the treatment reduced the parietal cell loss in CAIX‐KO mice in the subsequent months.

Conclusions

We propose that CAIX converts protons that either backflux or are extruded from the cells rapidly to CO₂ and H₂O, contributing to tight junction protection and gastric epithelial pH_i regulation. Lack of CAIX results in persistent acid backflux via claudin‐18 downregulation, causing loss of parietal cells, hypergastrinaemia and foveolar hyperplasia.

Identification of a novel aviadenovirus, designated pigeon adenovirus 2 in domestic pigeons (Columba livia)

The young pigeon disease syndrome (YPDS) affects mainly young pigeons of less than one year of age and leads to crop stasis, vomitus, diarrhea, anorexia and occasionally death. This disease is internationally a major health problem because of its seasonal appearance during competitions such as homing pigeon races or exhibitions of ornamental birds. While the etiology of YPDS is still unclear, adenoviruses are frequently discussed as potential causative agents. Electron microscopy of feces from a YPDS outbreak revealed massive shedding of adenovirus-like particles. Whole genome sequencing of this sample identified a novel adenovirus tentatively named pigeon adenovirus 2 (PiAdV-2). Phylogenetic and comparative genome analysis suggest PiAdV-2 to belong to a new species within the genus Aviadenovirus, for which we propose the name Pigeon aviadenovirus B. The PiAdV-2 genome shares 54.9% nucleotide sequence identity with pigeon adenovirus 1 (PiAdV-1). In a screening of further YPDS-affected flocks two variants of PiAdV-2 (variant A and B) were detected which shared 97.6% nucleotide identity of partial polymerase sequences, but only 79.7% nucleotide identity of partial hexon sequences. The distribution of both PiAdV-2 variants was further investigated in fecal samples collected between 2008 and 2015 from healthy or YPDS-affected racing pigeons of different lofts. Independent of their health status, approximately 20% of young and 13% of adult pigeon flocks harbored PiAdV-2 variants. Birds were free of PiAdV-1 or other aviadenoviruses as determined by PCRs targeting the aviadenovirus polymerase or the PiAdV-1 fiber gene, respectively. In conclusion, there is no indication of a correlation between YPDS outbreaks and the presence of PiAdV-2 or other aviadenoviruses, arguing against an causative role in this disease complex.

Variations in the presence of chloride cells in the gills of lampreys (Petromyzontiformes) and their evolutionary implications

Although confined to fresh water, non-parasitic species of lampreys and the landlocked parasitic sea lamprey, all of which were derived relatively recently from an adromous ancestors, still develop chloride cells, whose function in their ancestors was for osmoregulation in marine waters during the adult parasitic phase. In contrast, such cells are not developed by the non-parasitic least brook lamprey Lampetra aepyptera, which has been separated from its ancestor for >2 million years, nor by the freshwater parasitic species of the genus Ichthyomyzon. The length of time that a non-parasitic species or landlocked parasitic form or species has spent in fresh water is thus considered the overriding factor determining whether chloride cells are developed by those lampreys.

Relevance of UDP-glucuronosyltransferase polymorphisms for drug dosing: A quantitative systematic review

UDP-glucuronosyltransferases (UGT) catalyze the biotransformation of many endobiotics and xenobiotics, and are coded by polymorphic genes. However, knowledge about the effects of these polymorphisms is rarely used for the individualization of drug therapy. Here, we present a quantitative systematic review of clinical studies on the impact of UGT variants on drug metabolism to clarify the potential for genotype-adjusted therapy recommendations. Data on UGT polymorphisms and dose-related pharmacokinetic parameters in man were retrieved by a systematic search in public databases. Mean estimates of pharmacokinetic parameters were extracted for each group of carriers of UGT variants to assess their effect size. Pooled estimates and relative confidence bounds were computed with a random-effects meta-analytic approach whenever multiple studies on the same variant, ethnic group, and substrate were available. Information was retrieved on 30 polymorphic metabolic pathways involving 10 UGT enzymes. For irinotecan and mycophenolic acid a wealth of data was available for assessing the impact of genetic polymorphisms on pharmacokinetics under different dosages, between ethnicities, under comedication, and under toxicity. Evidence for effects of potential clinical relevance exists for 19 drugs, but the data are not sufficient to assess effect size with the precision required to issue dose recommendations. In conclusion, compared to other drug metabolizing enzymes much less systematic research has been conducted on the polymorphisms of UGT enzymes. However, there is evidence of the existence of large monogenetic functional polymorphisms affecting pharmacokinetics and suggesting a potential use of UGT polymorphisms for the individualization of drug therapy.

Global acetylation and methylation changes predict papillary urothelial neoplasia of low malignant potential recurrence: a quantitative analysis

Papillary urothelial neoplasia of low malignant potential (PUNLMP) recurs in approximately 35% of patients. Conventional histopathological assessment does not distinguish non-recurrent from recurrent PUNLMP. The aim of this study is to explore the differences in global histone acetylation and global DNA methylation between non-recurrent and recurrent PUNLMP. Acetylated histone H3 lysine 9 (AcH3K9) and 5-methylcytosine (5MeC) were investigated by immunohistochemistry (IHC) in 20 PUNLMP cases (10 non-recurrent and 10 recurrent), in 5 cases of normal urothelium (NU) and in 5 cases of muscle invasive pT2 urothelial carcinoma (UC). The total optical density of the nuclear staining was measured photometrically in at least 40 nuclei separately for the basal, intermediate and luminal positions in each case. Concerning the total optical density values for both acetylation and methylation, a decrease in staining is observed from non-recurrent PUNLMP to recurrent PUNLMP, at all nuclear locations. For acetylation the mean value in non-recurrent PUNLMP, intermediate between NU and UC, is closer to the former than to latter. The mean value in recurrent PUNLMP is closer to UC than to NU. In NU, non-recurrent and recurrent PUNLMP, the acetylation to methylation ratio decreased from the nuclei in basal position to those in the surface, the average for the above groups being 1.491, 1.611 and 1.746, respectively. Setting the observed values for NU at each sampling location to unity, acetylation shows a steady decrease, the percentages of changes in this nuclear location compared to NU being -5% in non-recurrent PUNLMP, -15% in recurrent PUNLMP and -24% in UC. Concerning methylation, there is a slight increase in non-recurrent PUNLMP (+5%), a decrease in recurrent PUNLMP (-19%) followed by a sharp rise for the UC (+61%). In conclusion, there are differences in global histone acetylation and DNA methylation patterns between non-recurrent and recurrent PUNLMP. Further studies are needed to elucidate the complex interplay between chromatin structure, its modifications and recurrence of PUNLMP.

Limited resection and free jejunal graft interposition for squamous cell carcinoma of the cervical oesophagus

BACKGROUND

Therapeutic strategies for cervical oesophageal squamous cell carcinoma (SCC) are controversial. Treatment options range from definitive radiotherapy to multimodal treatment. Outcome after limited resection and reconstruction with a free jejunal graft interposition was evaluated retrospectively.

METHODS

Patients with clinical T1-4 Nx M0 tumours treated between 1986 and 2006 were included.

RESULTS

Of 109 patients, 94 underwent preoperative chemoradiotherapy and 15 had a primary resection. Complete or partial preservation of the larynx was achieved in 93 patients (85.3 per cent). Minor and major complications occurred in 74.3 per cent, with 44.0 per cent of all patients having more than one complication. Reoperation was necessary in 29.4 per cent. The 30-day mortality rate was 1.8 per cent, and the in-hospital mortality rate 2.8 per cent. The complete R0 resection rate was 72.5 per cent. Median overall survival was 34.3 months; 1-, 3- and 5-year survival rates were 83.8, 47.0 and 47.0 per cent respectively. Survival was not influenced by complications (P = 0.401) or reoperation (P = 0.428).

CONCLUSION

Despite high complication and reoperation rates, the mortality rate was low, even after preoperative chemoradiation. This complex surgical strategy is a treatment option for cervical SCC in oncological centres with an infrastructure providing multidisciplinary management.

Functional imaging of unilateral tinnitus using fMRI

CONCLUSIONS

This article shows that the inferior colliculus plays a key role in unilateral subjective tinnitus.

OBJECTIVES

The major aim of this study was to determine tinnitus-related neural activity in the central auditory system of unilateral tinnitus subjects and compare this to control subjects without tinnitus.

SUBJECTS AND METHODS

Functional MRI (fMRI) was performed in 10 patients (5 males) with unilateral tinnitus (5 left-sided, 5 right-sided) and 12 healthy subjects (6 males); both groups had normal hearing or mild hearing loss. fMRI experiments were performed using a 3T Philips Intera Scanner. Auditory stimuli were presented left or right and consisted of dynamically rippled broadband noise with a sound pressure level of 40 or 70 dB SPL. The responses of the inferior colliculus and the auditory cortex to the stimuli were measured.

RESULTS

The response to sound in the inferior colliculus was elevated in tinnitus patients compared with controls without tinnitus.

Cervical squamous cell carcinoma of the esophagus-a unique series of limited resection and free jejunal graft interposition after neoadjuvant RCTx in 94 patients

4572

Background: The treatment of cervical squamous cell carcinoma (SCC) is discussed controversial. A limited resection of the cervical esophagus and reconstruction with a free jejenunal graft interposition using a microsurgical technique has been evaluated in our department. Methods: From 1986–2006 94 patients with the initial staging uT2–4, N any cM0 (75 male, 19 female; age 56+9.6, range: 19–74 years) with cervical SCC of the esophagus were treated with limited esophageal resection and reconstructed with a free jejunal autograft in combination after neoadjuvant RCTx within phase II studies. The median follow up is 23 months (0.1–120). Results: Laryngectomie had to be performed in 13 patients (14%). Recurrent nerve palsy on one side was found in 15/77 (19.5%) and on both sides in 13/77 (17%). Complications occurred in 70 (75%) of the patients, 47% of the patients had more than one complication. Reoperations were necessary in 29 patients (31%). The 30-day mortality was 2/94 (2.1%). Median survival is 29.9 months (1-, 3 and 5-year survival rates: 81%, 43%, 41%). 27/94 (29%) patients showed complete tumor regression (ypT0) after RCTx. Prognostic factors are complete tumor regression (p=0.007), ypT-(p=0.006), the R-category (p=0.018), but not the ypN-category (p=0.06). Neither the occurrence of complications (p=0.57) nor reoperation (p=.89) are associated with survival. The complete resection rate was 76 % (71/94). Median survival is 34.3 months, median recurrence free survival is 21.4 months for the R0 resected patients. 30/71 (42%) had a recurrence (locoregional in 27% (19/71), distant metastases in 10% (7/71) and a combination of both in 6% (4/71). Conclusions: Limited resection of the esophagus and reconstruction by a free jejunal graft after neoadjuvant RCTx is highly sophisticated and complex. Despite a high complication and reoperation rate the results are excellent with a low mortality and a good prognosis. This approach seems to be appropriate for cervical SCC in oncological centers with an infrastructure providing interdisciplinary management. Comparable data for cervical SCC of the esophagus without the inclusion of hypopharyx carcinoma do not exist in literature so far.

No significant financial relationships to disclose.

Long-Term Evaluation of Treatment of Chronic, Therapeutically Refractory Tinnitus by Neurostimulation

OBJECTIVE

Long-term evaluation of treatment of chronic, therapeutically refractory tinnitus by means of chronic electrical stimulation of the vestibulocochlear nerve.

PATIENTS

Inclusion criteria were severe, chronic, therapeutically refractory, unilateral tinnitus and severe hearing loss at the ipsilateral site. Out of 6 patients, 4 patients were selected for long-term evaluation. Two patients were not evaluated because of premature dropout.

MATERIAL AND METHODS

A stimulation electrode was placed around the vestibulocochlear nerve through a retrosigmoid approach and connected to a subcutaneously positioned pulse generator via an extension cable. Follow-up was performed 3 months and 42.5 months after implantation. Three measures for treatment outcome were used. First, effect sizes were determined by means of the total Tinnitus Handicap Inventory (THI) score using Cohen's formula. Second, general and tinnitus-specific audiometric tests were performed in on and off conditions of the neurostimulation system. Third, recordings were noted for tinnitus severity and treatment success on a visual analogue scale.

RESULTS

All 4 patients reported successful treatment with neurostimulation. The effect size after 3 months was 0.7, indicating an average effect, while the effect size measured during long-term follow-up was 1.75, indicating a substantial effect with major clinical implications. No changes in hearing level for both ears were measured. The neurostimulation system did not change the tinnitus pitch in any of the patients, and resulted in a minimal reduction of tinnitus loudness in only 2 patients. In all 4 patients the original tinnitus sound was replaced by another, pleasantly perceived sound. The average VAS score of perceived tinnitus severity was reduced from 8 to 3.25. The average VAS score for treatment success was 7.25.

CONCLUSIONS

The long-term follow-up of neurostimulation treatment for chronic tinnitus shows promising results. Long-term results were better than those determined after a 3-month follow-up. In all patients the tinnitus was replaced by another sound, which was perceived as pleasant. Further studies are needed before accepting neurostimulation as a treatment modality for chronic, therapeutically refractory tinnitus.

Blood interleukin 12 as preoperative predictor of fatal postoperative sepsis after neoadjuvant radiochemotherapy

Introduction

The value of preoperative whole-blood interleukin (IL) 12 levels in predicting death from postoperative sepsis was evaluated, in patients stratified by underlying malignancy, neoadjuvant tumour treatment and surgical procedure.

Methods

Blood samples were collected from 1444 patients before major surgery. Whole blood was incubated with Escherichia coli lipopolysaccharide (LPS) and IL-12 production in supernatants was assessed by enzyme-linked immunosorbent assay. The prognostic impact of ability to synthesize IL-12 before surgery was investigated in patient subgroups with respect to sepsis-related mortality using multivariate binary logistic regression analysis.

Results

IL-12 synthesizing capability in patients who survived sepsis was significantly higher than that in patients who developed fatal sepsis (P = 0·006). In multivariate analysis only IL-12 was associated with a lethal outcome from postoperative sepsis (P = 0·006). The prognostic impact of IL-12 was evident in patients with underlying malignancy (P = 0·011) and in those who had undergone neoadjuvant tumour treatment (P = 0·008). When patients were analysed according to the type of neoadjuvant therapy, preoperative ability to synthesize IL-12 had a significant prognostic impact in patients who had neoadjuvant radiochemotherapy (P = 0·026), but not in those who had neoadjuvant chemotherapy.

Conclusion

IL-12 production after stimulation of whole blood with LPS appears to be useful for the preoperative assessment of risk of sepsis-related death after operation in patients who have undergone neoadjuvant radiochemotherapy.

[Indicators for early prediction of outcome in sepsis]

Sepsis is still a major cause of postoperative morbidity and mortality. Numerous biochemical indicators have been evaluated regarding their potential in predicting prognosis in sepsis. Generally, one must differentiate between indicators: those for preoperative detection of patients at risk for lethal sepsis and those for early prediction of lethal outcome of septic complications. The first include the analysis of mononuclear phagocyte interleukin (IL)-12-synthesizing capability. Reduced IL-12 levels were associated with higher lethality. Cytokine-associated gene polymorphisms such as the loss of monocyte HLA-DR expression and homozygotism for the tumor necrosis factor B2 allele have a place in preoperative risk evaluation, as they were associated with worse prognosis in sepsis. Among the most important biochemical indicators for early prediction of lethal outcome in sepsis are decreased L-selectin and elevated IL-18, IL-6, and PCT plasma concentrations. Increased nuclear factor kappaB activity in mononuclear phagocytes and elevated calcitonin gene-related protein plasma concentrations were associated with unfavourable prognosis.

Abdomino-rechts-thorakale Ösophagusresektion mit intrathorakaler Anastomose beim Barrett-Karzinom

The modified technique of abdomino-right-thoracic esophagectomy (the Lewis-Tanner approach) is increasingly being favoured as the surgical procedure of choice in patients with resectable adenocarcinoma of the distal esophagus, so-called Barrett's cancer. The technical details of this procedure and the reconstruction of gastrointestinal continuity using a gastric tube with high intrathoracic anastomosis are illustrated, as they have proved useful in our own practice during recent years.

Techniken der Tracheotomie/Tracheostomie

Tracheostomy has become the method of choice in managing patients requiring long-term mechanical ventilation. At present, there are several alternatives to conventional surgical tracheostomy such as percutaneous dilatational techniques according to Ciaglia, Frova, and Fantoni. The basic principle of these new techniques is percutaneous puncture of the trachea and subsequent dilatation of the puncture channel until the tracheal cannula can be inserted. The advantages are "bedside" performance in the intensive care unit and the use of minimal technical equipment. Nevertheless, dilatation tracheostomy is not always technically feasible and safe. Some significant complications and contraindications have been recognized recently. This should be taken into account when planning tracheostomy in long-term ventilated patients. Compared to conventional surgical tracheostomy, this new procedure retains its value and benefit only if these contraindications are carefully observed.

[Anastomotic leaks in the upper gastrointestinal tract]

Anastomotic leaks are still among the most common severe postoperative complications and account for the majority of postoperative deaths after esophagectomy and gastrectomy. Every disturbance of the normal postoperative course should trigger surgeons to consider an underlying anastomotic leak and initiate a specific diagnostic workup. This includes direct endoscopic inspection of the anastomosis to evaluate the vitality of the anastomosed organs and the size of the leak. Adequate external drainage of the leak and prevention of further contamination are the primary therapeutic goals. Selection of therapy is guided by the available modalities for sufficiently draining the leak and avoiding sepsis. The spectrum of therapeutic options ranges from simple opening of the neck incision in cervical esophageal anastomoses, interventional placement of drains, to endoscopic intervention with closure of the fistula or placement of stents, and reoperation with exclusion, diversion, or discontinuity resection.

LC-MS/MS analysis of pholedrine in a fatal intoxication case

Pholedrine (4'-hydroxymethamphetamine) is a cardiovascular agent exerting hypertensive and adrenergic effects. High doses may cause a drop in the peripheral circulation blood flow and increase blood pressure, heart rate and body temperature up to a state of central respiratory paralysis. A 15-year-old girl who suffered from heavy agitation and hallucinations was admitted to the intensive care unit in a comatose state. The clinical findings included a maximum heart rate of 170 bpm and a body temperature of 43.8 degrees C. Resuscitation measures were in vain and abandoned after approximately 2h. A toxicological emergency analysis using GC/MS revealed a considerable amount of pholedrine in blood and urine. A method for determining pholedrine in human body fluids utilizing high-performance liquid chromatography (HPLC)/tandem mass spectrometry (LC-MS/MS) with a turbo ion-spray source was developed, using D11-methamphetamine and D5-methylenedioxymethamphetamine as internal standards. Samples were prepared by SPE extraction using SPEC-C18AR/MP3((R)) columns, which yielded the best extraction recovery (67%). Chromatographic separation was achieved at pH 5 on an RP-18 stationary phase applying gradient elution from 50 to 70% of B (methanol/acetonitrile 3/1 (v/v), 0.02% acetic acid) in A (5mM ammonium acetate/acetonitrile 95/5 (v/v), 0.02% acetic acid). Supra-pure acetic acid was added to the post-column effluent with a flow rate of 0.2 microl/min to optimize ionization. Detection was carried out in the positive ionization, multiple reaction monitoring (MRM) mode. The chromatograms showed no interference from other substances. The limit of detection (LOD, S/N=3) of pholedrine was 0.8 ng/ml and its lower limit of quantification (LLOQ, S/N=10) 3ng/ml. The calibration curve was linear (r=0.999) in the range 1-100 ng/ml. Samples with higher concentrations were diluted to suit the working range. The intra-day R.S.D. between 5 and 80 ng/ml were 3.8-8.7% and the inter-day R.S.D. between 5 and 100 ng/ml were 6.7-10.7%. The pholedrine concentrations in blood and urine collected when the girl was still alive were 16.1 microg/ml (R.S.D. 10.5%) and 1120 microg/ml (R.S.D. 8%), respectively. In post-mortem samples, they were 23.0 microg/ml (R.S.D. 5.1%) in heart blood and 27.3 microg/g (R.S.D. 6.6%) in the liver.

Focal neurometabolic alterations in mice deficient for succinate semialdehyde dehydrogenase

Metabolite profiling in succinate semialdehyde dehydrogenase (SSADH; Aldh5a1-/-) deficient mice previously revealed elevated gamma-hydroxybutyrate (GHB) and total GABA in urine and total brain and liver extracts. In this study, we extend our metabolic characterization of these mutant mice by documenting elevated GHB and total GABA in homogenates of mutant kidney, pancreas and heart. We quantified beta-alanine (a GABA homolog and putative neurotransmitter) to address its potential role in pathophysiology. We found normal levels of beta-alanine in urine and total homogenates of mutant brain, heart and pancreas, but elevated concentrations in mutant kidney and liver extracts. Amino acid analysis in mutant total brain homogenates revealed no abnormalities except for significantly decreased glutamine, which was normal in mutant liver and kidney extracts. Regional amino acid analysis (frontal cortex, parietal cortex, hippocampus and cerebellum) in mutant mice confirmed glutamine results. Glutamine synthetase protein and mRNA levels in homogenates of mutant mouse brain were normal. We profiled organic acid patterns in mutant brain homogenates to assess brain oxidative metabolism and found normal concentrations of Kreb's cycle intermediates but increased 4,5-dihydroxyhexanoic acid (a postulated derivative of succinic semialdehyde) levels. We conclude that SSADH-deficient mice represent a valid metabolic model of human SSADH deficiency, manifesting focal neurometabolic abnormalities which could provide key insights into pathophysiologic mechanisms.

Quantitative study of breast cancer progression: different pathways for various in situ cancers

The chromatin pattern in nuclei from breast ductal proliferative lesions was quantitatively evaluated with the objective of deriving measures of tumor progression. A total of 110 cases were analyzed. There were 38 cases of normal tissue or benign proliferative lesions, 41 cases of ductal carcinoma in situ (DCIS), and 31 cases of microinfiltrating DCIS and of infiltrating cancer. A total of 9424 nuclei were analyzed. High-resolution images were digitally recorded. For each nucleus, 93 karyometric features descriptive of the spatial and statistical distribution of the nuclear chromatin were computed. Data analysis included establishing a profile of relative deviations of each feature from "normal," called the nuclear signature, and of lesion signatures as well as of trends of lesion progression. Two trends of evolution could be discerned: one from normal to hyperplasia, atypical hyperplasia, and comedo DCIS as representative of high-grade lesions; and the other from normal to hyperplasia to cribriform DCIS, solid DCIS, and infiltrating cancer, representing lower grade lesions. The nuclei in microinfiltrating foci are distinctly different from nuclei in high-grade comedo DCIS. The nuclei in microinfiltrating foci have a statistically significantly lower nuclear abnormality. They may represent outgrowing clones.

High resolution structure of the large ribosomal subunit from a mesophilic eubacterium

We describe the high resolution structure of the large ribosomal subunit from Deinococcus radiodurans (D50S), a gram-positive mesophile suitable for binding of antibiotics and functionally relevant ligands. The over-all structure of D50S is similar to that from the archae bacterium Haloarcula marismortui (H50S); however, a detailed comparison revealed significant differences, for example, in the orientation of nucleotides in peptidyl transferase center and in the structures of many ribosomal proteins. Analysis of ribosomal features involved in dynamic aspects of protein biosynthesis that are partially or fully disordered in H50S revealed the conformations of intersubunit bridges in unbound subunits, suggesting how they may change upon subunit association and how movements of the L1-stalk may facilitate the exit of tRNA.

Ribosomal crystallography: from poorly diffracting microcrystals to high-resolution structures

The cellular organelles translating the genetic code into proteins, the ribosomes, are large, asymmetric, flexible, and unstable ribonucleoprotein assemblies, hence they are difficult to crystallize. Despite two decades of intensive effort and thorough searches for suitable sources, so far only three crystal types have yielded high-resolution structures: two large subunits (from an archaean and from a mesophilic eubacterium) and one thermophilic small subunit. These structures have added to our understanding of decoding, have revealed dynamic aspects of the biosynthetic process, and have indicated the strategies adopted by ribosomes for interacting between themselves as well as with inhibitors, factors and substrates.

Histologic tumor type is an independent prognostic parameter in esophageal cancer: lessons from more than 1,000 consecutive resections at a single center in the Western world

OBJECTIVE

To analyze the changing pattern in tumor type and postoperative deaths at a national referral center for esophageal cancer in the Western world and to assess prognostic factors for long-term survival after resection.

SUMMARY BACKGROUND DATA

During the past two decades, the epidemiology and treatment strategies of esophageal cancer have changed markedly in the Western world. The influence of these factors on postoperative deaths and long-term prognosis has not been adequately evaluated.

METHODS

Between 1982 and 2000, 1,059 patients with primary esophageal squamous cell cancer or adenocarcinoma had resection with curative intention at a single center. Patient and tumor characteristics and details of the surgical procedure and outcome were documented during this period. Follow-up was available for 95.8% of the patients. Changing patterns in tumor type and postoperative deaths were analyzed. Prognostic factors for long-term survival were assessed by multivariate analysis.

RESULTS

The prevalence of adenocarcinoma in patients with resected esophageal cancer increased markedly during the study period. The postoperative death rate decreased from about 10% before 1990 to less than 2% since 1994, coinciding with the introduction of a procedure-specific composite risk score and exclusion of high-risk patients from surgical resection. In addition to the well-established prognostic parameters, tumor cell type "adenocarcinoma" was identified as a favorable independent predictor of long-term survival after resection. The independent prognostic effect of tumor cell type persisted in the subgroups of patients with primary resection and patients with primary resection and R0 category.

CONCLUSION

Esophagectomy for esophageal cancer has become a safe procedure in experienced hands. Esophageal adenocarcinoma has a better long-term prognosis after resection than squamous cell carcinoma.

[Esophageal carcinoma: 2-stage operation for preventing mediastinitis in high risk patients]

Strict patient selection, standardization of the surgical technique and advances in peri- and postoperative management have in experienced centers resulted in a decrease in postoperative mortality after esophagectomy and reconstruction to less than 5% in recent years. The previously common and potentially lethal pulmonary and cardiac complications have lost their impact on outcome. Today, septic complications, which usually arise from the reconstruction phase, constitute the major morbidity and mortality factors in the surgical therapy of esophageal cancer. These complications pose a particular problem for patients with compromised organ function and patients after neoadjuvant combined radiochemotherapy. In these situations a surgical safety concept with a two-stage procedure, i.e., delay of reconstruction after resection for 8-10 days, can markedly reduce the otherwise substantial postoperative mortality. A two-stage procedure thus offers patients a chance of a potentially curative surgical therapy who would otherwise be excluded from resection.

Nisoldipine increases the bioavailability of endothelial NO

Different observations suggest that dihydropyridine calcium antagonists alter endothelial NO release. Therefore, in a first step we investigated whether part of the nisoldipine (a dihydropyridine calcium antagonist with a possible selectivity for coronaries)-induced vasorelaxation was due to an NO release from the endothelium in porcine coronary arteries. Secondly, we directly measured whether nisoldipine increased NO release from rabbit aorta or the nisoldipine enantiomers (Bay R 1223, Bay R 1224) from rat aorta. Thirdly, we determined whether nisoldipine exerted antioxidative properties in segments of porcine aorta with intact endothelium. Blocking endothelial NO synthase with N-nitro-L-arginine resulted in a significant shift of the relaxation curve to higher concentrations. Accordingly, nisoldipine induced a concentration-dependent release of NO (direct electrochemical detection) from native endothelium which already started at a therapeutical level (1 nmol/l nisoldipine/6.5 +/- 1.2 nmol/l NO). To evaluate whether this effect was due to an antioxidative protection of NO, we examined the influence of nisoldipine on a hyperglycemia (30 mmol/l, 20 min)-induced reactive oxygen species release of vascular endothelium from porcine coronary arteries. Nisoldipine concentration-dependently reduced the reactive oxygen species release (>50%; 10 micromol/l). Moreover, a carbachol-induced NO release (rabbit aorta) which was significantly diminished by hyperglycemia was completely restored in the presence of nisoldipine (3 micromol/l). We conclude that nisoldipine increases the NO bioavailability which may result in an ameliorated endothelial function.

Multimegapixel images in histopathology

OBJECTIVE

To describe methods and procedures for the assembly of very large scale microscopic image arrays.

STUDY DESIGN

Microscopic imagery was recorded on different video microphotometers, equipped either with a three-chip CCD Sony MD 760 (Park-ridge, New Jersey, U.S.A.), a COHU vidicon (San Diego, California, U.S.A.) or a PROGRES camera (JenOptik, Jena, Germany), yielding image tiles of 512 x 470, 512 x 470 or 1,496 x 1,120 pixels, respectively. The slide was moved while mounted on a Maerzheuser scanning stage with 0.1-micron precision, under computer control. The MERGE software. (Optical Sciences Center, University of Arizona, Tucson, Arizona, U.S.A.) was written in C and currently implemented on a Sun. Ultra Sparc 2 computer (Sun Microsystems, Palo Alto, California, U.S.A.).

RESULTS

The MERGE program allows the assembly of very large scale digitized image arrays preserving exact tile alignment such that even within a single nucleus, highly precise registration is maintained. Images up to 150 megapixels have been assembled, although most practical applications required assembly of only 60-300 tiles.

CONCLUSION

The single limiting effect of assembling very large image arrays is the problem of angular misalignment between CCD scan line orientation and scanning stage travel direction. For misalignment of even less than 1 degree, very large arrays need substantial tile overlap. For object areas extending over only 5-10 mm, the effects can be controlled.

Ischemic spinal cord syndrome after transthoracic esophagectomy: two cases of a rare neurologic complication

Anterior spinal artery syndrome (ASAS) is a rare complication after surgery of the thoracic or abdominal aorta. The sulco commissuralis syndrome represents a partial or incomplete ASAS. We report two cases of ischemic spinal cord syndromes after transthoracic esophagectomy. This represents a prevalence of this syndrome of 0.2% in more than 1000 consecutive esophagectomies performed at our institution. Patient 1 developed an ASAS on the first day after esophagectomy. Patient 2 showed the pathognomonic clinical signs associated with sulco commissuralis syndrome after an asymptomatic window. In both patients, the extent of the neurologic symptoms initially improved but then remained unchanged for the rest of the follow-up of 9 and 12 months. Although the prognosis of neurologic syndromes resulting from spinal cord infarction is poor, preoperative tests to identify patients at risk appear not to be justified because of the very low incidence of these syndromes after esophagectomy and the poor sensitivity and specificity of currently available diagnostic modalities. However, the possibility of ischemic spinal cord syndrome should be kept in mind when patients present with neurologic symptoms after esophagectomy.

Nifedipine increases endothelial nitric oxide bioavailability by antioxidative mechanisms

Short-term treatment of the endothelium with dihydropyridine calcium antagonists resulted in an increased release in NO that is not due to a modulation of L-type calcium channels, because macrovascular endothelial cells do not express this channel. We investigated whether long-term (48 hours) treatment of porcine endothelial cell cultures with the dihydropyridine calcium antagonist nifedipine resulted in a similar enhanced NO liberation. Regarding to the underlying mechanism, we examined whether (1) nifedipine changed the mRNA and protein levels of the constitutive endothelial NO synthase (NOS) in endothelial cell cultures or (2) nifedipine exerts an NO protective effect via its antioxidative properties, as revealed in a cell culture model and with native endothelium from porcine coronary arteries. Nifedipine induced a significant time- and concentration-dependent increase (132+/-47%, 1 micromol/L, 40 minutes' incubation) in the basal NO liberation (oxyhemoglobin assay). This increased NO release was not due to elevated NOS (type III) mRNA (Northern blot analysis) and protein (Western blot analysis) levels. However, nifedipine (both short- and long-term treatment) significantly reduced the basal and glucose (20 and 30 mmol/L)-stimulated formation of reactive oxygen species (lucigenin assay) of endothelial cell cultures and native cells. We conclude that the calcium antagonist nifedipine enhances the bioavailability of endothelial NO without significantly altering the NOS (type III) mRNA and protein expression, possibly via an antioxidative protection. This increased NO availability may cause part of the vasodilation and might contribute to the antithrombotic, antiproliferative, and antiatherosclerotic effects of dihydropyridine calcium antagonists.

[Postoperative complications--what is often? What is rare?]

The postoperative course after major (elective) digestive surgical procedures was prospectively analysed in 5693 patients. Postoperative complications were documented in 553 patients (9.7%). There were general complications (not related to surgery) in 97 patients (17.5%) and surgical complications (related to surgery) in 456 patients (82.5%). The most frequent surgical complication was abdominal sepsis in 72.1% followed by postoperative bleeding (17.1%) and others (10.7%). The leading cause for abdominal sepsis was anastomotic leakage in 207 patients (70.2%). Bedside diagnostic procedures like sonography, analysis of fluid drainage and endoscopy could identify the underlying problem of abdominal sepsis in 60.9% of cases. The mortality rate of all studied patients was (113/5693 patients) 1.9%.

Deciduoid pleural mesothelioma affecting a young female without prior asbestos exposure

Pleural mesothelioma is commonly associated to asbestos exposure. A 40-year-old woman is described who presented with shortness of breath. She had a smoking history but no history of asbestos exposure. Chest radiography and computed tomography showed a large tumour on the right lower lung. An open pleural biopsy was performed. A metastatic adenocarcinoma of the pleura was primarily diagnosed. The tumour progressed and after surgical excision an accurate histological and immunohistochemical examination was performed. It revealed a pleural mesothelioma with a deciduoid differentiation that has not been described before.

Structure of functionally activated small ribosomal subunit at 3.3 angstroms resolution

The small ribosomal subunit performs the decoding of genetic information during translation. The structure of that from Thermus thermophilus shows that the decoding center, which positions mRNA and three tRNAs, is constructed entirely of RNA. The entrance to the mRNA channel will encircle the message when a latch-like contact closes and contributes to processivity and fidelity. Extended RNA helical elements that run longitudinally through the body transmit structural changes, correlating events at the particle's far end with the cycle of mRNA translocation at the decoding region. 96% of the nucleotides were traced and the main fold of all proteins was determined. The latter are either peripheral or appear to serve as linkers. Some may assist the directionality of translocation.

Targeting exposed RNA regions in crystals of the small ribosomal subunits at medium resolution

Within the framework of ribosomal crystallography, the small subunits are being analyzed, using crystals diffracting to 3 A resolution. The medium resolution electron density map of this subunit, obtained by multiple isomorphous replacement, show recognizable morphologies, strikingly similar to the functional active conformer of the small ribosomal subunit. It contains elongated dense features, traceable as RNA chains as well as globular regions into which the structures determined for isolated ribosomal proteins, or other known structural motifs were fitted. To facilitate unbiased map interpretation, metal clusters are being covalently attached either to the surface of the subunits or to DNA oligomers complementary to exposed ribosomal RNA. Two surface cysteines and the 3' end of the 16S ribosomal RNA have been localized. Targeting several additional RNA regions shed light on their relative exposure and confirmed previous studies concerning their functional relevance.

Poly(DL-lactide-epsilon-caprolactone) nerve guides perform better than autologous nerve grafts

The aim of this study was to compare the speed and quality of nerve regeneration after reconstruction using a biodegradable nerve guide or an autologous nerve graft. We evaluated nerve regeneration using light microscopy, transmission electron microscopy and morphometric analysis. Nerve regeneration across a short nerve gap, after reconstruction using a biodegradable nerve guide, is faster and qualitatively better, when compared with nerve reconstruction using an autologous nerve graft. Therefore, we conclude that in the case of a short nerve gap (1 cm), reconstruction should be carried out using a biodegradable nerve guide constructed of a copolymer of DL-lactide and epsilon-caprolactone.

Translocation of Yersinia entrocolitica across reconstituted intestinal epithelial monolayers is triggered by Yersinia invasin binding to beta1 integrins apically expressed on M-like cells

Yersinia enterocolitica cross the intestinal epithelium via translocation through M cells, which are located in the follicle-associated epithelium (FAE) of Peyer's patches (PP). To investigate the molecular basis of this process, studies were performed using a recently developed in vitro model, in which the enterocyte-like cell line Caco-2 and PP lymphocytes are co-cultured in order to establish FAE-like structures including M cells. Here, we demonstrate that Y. enterocolitica does not adhere significantly to the apical membrane of differentiated enterocyte-like Caco-2 cells that express binding sites for Ulex europaeus agglutinin (UEA)-1. In contrast, Y. enterocolitica adhered to, and was internalized by, cells that lacked UEA-1 binding sites and displayed a disorganized brush border. These cells were considered to be converted to M-like cells. Further analysis revealed that part of these cells expressed beta1 integrins at their apical surface and, as revealed by comparison of wild-type and mutant strains, interacted with invasin of Y. enterocolitica. Consistently, anti-beta1 integrin antibodies significantly inhibited internalization of inv-expressing yersiniae. Experiments with Yersinia mutant strains deficient in YadA or Yop secretion revealed that these virulence factors play a minor role in this process. After internalization, yersiniae were transported within LAMP-1-negative vacuoles to, and released at, the basal surface. Internalization and transport of yersiniae was inhibited by cytochalasin D, suggesting that F-actin assembly is required for this process. These results provide direct evidence that expression of beta1 integrins at the apical surface of M cells enables interaction with the invasin of Y. enterocolitica, and thereby initiates internalization and translocation of bacteria.