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.