Argyrophilic grain disease in individuals younger than 75 years: clinical variability in an under-recognized limbic tauopathy

BACKGROUND AND PURPOSE

Argyrophilic grain disease (AGD) is a limbic-predominant 4R-tauopathy. AGD is thought to be an age-related disorder and is frequently detected as a concomitant pathology with other neurodegenerative conditions. There is a paucity of data on the clinical phenotype of pure AGD. In elderly patients, however, AGD pathology frequently associates with cognitive decline, personality changes, urine incontinence and cachexia. In this study, clinicopathological findings were analysed in individuals younger than 75.

METHODS

Patients were identified retrospectively based on neuropathological examinations during 2006-2017 and selected when AGD was the primary and dominant pathological finding. Clinical data were obtained retrospectively through medical records.

RESULTS

In all, 55 patients (2% of all examinations performed during that period) with AGD were identified. In seven cases (13%) AGD was the primary neuropathological diagnosis without significant concomitant pathologies. Two patients were female, median age at the time of death was 64 years (range 51-74) and the median duration of disease was 3 months (range 0.5-36). The most frequent symptoms were progressive cognitive decline, urinary incontinence, seizures and psychiatric symptoms. Brain magnetic resonance imaging revealed mild temporal atrophy.

CONCLUSIONS

Argyrophilic grain disease is a rarely recognized limbic tauopathy in younger individuals. Widening the clinicopathological spectrum of tauopathies may allow identification of further patients who could benefit from tau-based therapeutic strategies.

Susceptibility-Weighted MR Imaging Hypointense Rim in Progressive Multifocal Leukoencephalopathy: The End Point of Neuroinflammation and a Potential Outcome Predictor

BACKGROUND AND PURPOSE

Progressive multifocal leukoencephalopathy (PML) represents a life-threatening demyelinating disorder of the brain caused by reactivation of a rare opportunistic infection with JC Polyomavirus. The aims of this study were to describe the incidence of a susceptibility-weighted imaging hypointense rim in patients with multifocal leukoencephalopathy and to explore the histologic correlates and prognostic value of the rim with regard to the clinical outcome.

MATERIALS AND METHODS

This retrospective study included 18 patients with a definite diagnosis of progressive multifocal leukoencephalopathy. Ten patients were HIV-positive, 3 patients had natalizumab-associated progressive multifocal leukoencephalopathy, 1 patient had multiple myeloma, 3 patients had a history of lymphoma, and 1 was diagnosed with acute myeloid leukemia. Patients were divided into short- (up to 12 months) and long-term (>12 months) survivors. A total of 93 initial and follow-up MR imaging examinations were reviewed. On SWI, the presence and development of a hypointense rim at the periphery of the progressive multifocal leukoencephalopathy lesions were noted. A postmortem histologic examination was performed in 2 patients: A rim formed in one, and in one, there was no rim.

RESULTS

A total of 73 progressive multifocal leukoencephalopathy lesions were observed. In 13 (72.2%) patients, a well-defined thin, linear, hypointense rim at the periphery of the lesion toward the cortical side was present, while in 5 (27.8%) patients, it was completely absent. All 11 long-term survivors and 2 short-term survivors presented with a prominent SWI-hypointense rim, while 5/7 short-term survivors did not have this rim.

CONCLUSIONS

The thin, uniformly linear, gyriform SWI-hypointense rim in the paralesional U-fibers in patients with definite progressive multifocal leukoencephalopathy might represent an end-point stage of the neuroinflammatory process in long-term survivors.

Prominent psychiatric symptoms in patients with Parkinson's disease and concomitant argyrophilic grain disease

In Parkinson's disease (PD), cognitive decline and psychiatric symptoms may occur and very often co-exist, eventually leading to PD-dementia. We report three patients with PD who presented striking psychiatric manifestations along with mild cognitive decline not progressing to dementia across the course of disease and in which postmortem neuropathological study revealed, besides alpha-synuclein inmunoreactive Lewy-body pathology, concomitant four-repeat tau positive argyrophilic grain pathology. We consider that argyrophilic grains might have modulated the clinical presentation of PD in these patients, being the main substrate of their prominent psychiatric symptoms in the absence of definite dementia.

Hirano body-rich subtypes of Creutzfeldt-Jakob disease

BACKGROUND

In definite Creutzfeldt-Jakob disease (CJD), morphological and immunohistochemical patterns are useful to identify molecular subtypes. Severe cerebellar pathology and hippocampal involvement helps to identify VV subtypes. The rare VV1 variant (<1%), more frequent in young individuals, is additionally characterized by the presence of ballooned neurones in affected areas. In 1985, Cartier et al. described a family cluster of three individuals with an ataxic CJD form, showing, in addition to severe cerebellar and hippocampal involvement, the presence of frequent Hirano bodies (HB) in CA1 pyramidal neurones. HB are frequently found in aged individuals with Alzheimer pathology although they are not a specific finding.

AIMS AND METHODS

In this study, we evaluated the presence of HB in hippocampi of 54 genetically and molecularly characterized CJD cases, aiming to elucidate whether additional morphological features could be helpful to point to molecular subtypes.

RESULTS

We identified nine cases (four VV1, one out of three MV2K, three out of six MV2K+2C and one MV carrying a 96-base pair insertion) with abundant, partly bizarre and clustered HB in CA1 sector, not observed in other subtypes. The presence of HB was independent of hippocampal involvement by the disease itself.

CONCLUSIONS

Clusters of abundant HB might be found in rare CJD subtypes such as VV1, MV2K/MV2K+2C and some genetic cases. In addition to histopathological and PrP immunohistochemical deposition patterns, their presence might be a useful additional morphologic feature that could point to the molecular subtype, especially when genetic and/or Western blot analyses are not available.

Clinical features and APOE genotype of pathologically proven early-onset Alzheimer disease

OBJECTIVES

Early-onset Alzheimer disease (EOAD) diagnosis often represents a challenge because of the high frequency of atypical presentations. Our aim was to describe the clinical features, APOE genotype, and its pathologic correlations of neuropathologic confirmed EOAD.

METHODS

Retrospective review of clinical data (age at onset, family history, clinical presentation, diagnostic delay, diagnosis) and APOE genotype of patients with neuropathologically confirmed EOAD (<60 years).

RESULTS

Forty cases were selected. Mean age at onset was 54.5 years (range 46-60). The mean disease duration was 11 years with a mean diagnostic delay of 3.1 years. A total of 37.5% had a nonmemory presentation. Behavioral/executive dysfunction was the most prevalent atypical presentation. Incorrect initial clinical diagnoses were common (53%) in patients with atypical presentations, but rare when anterograde amnesia was the presenting symptom (4%). The incorrect initial clinical diagnoses were 2 behavioral variant frontotemporal lobar degeneration, 2 normal pressure hydrocephalus, 1 semantic dementia, 1 primary progressive aphasia, 1 corticobasal degeneration, 1 pseudodementia with depression, and 1 unclassifiable dementia. APOE genotype was ε3/ε3 in 59%, with no significant differences between typical and atypical presentations. APOE ε4 was 3.3 times more frequent in subjects with family history of AD. A total of 97.5% of the cases presented advanced neurofibrillary pathology. A total of 45% of the patients had concomitant Lewy body pathology although localized in most cases and without a significant clinical correlate.

CONCLUSION

One third of patients with pathologic confirmed EOAD presented with atypical symptoms. Patients with EOAD with nonamnestic presentations often receive incorrect clinical diagnoses.

The unextractable organic fraction of the pueblito de allende meteorite: evidence for its indigenous nature

The Pueblito de Allende meteorite contains only 0.1-0.5 ppm of solvent-extractable carbon, most or all of which is due to terrestrial contamination. Determinations of the total carbon content gives values from 0.23 to 0.35 per cent. The presumed indigenous insoluble carbon is thus present in a ratio of 2300:1 relative to contaminant carbon. A sample of the meteorite was extracted with a deuterated solvent containing benzene:methanol (4:1 w/w) to remove contaminants and then was subjected to pyrolysis-gas chromatography-mass spectrometry to investigate the nature of the remaining carbon. The pyrolysis products (about 20 ppm) consisted chiefly of aromatic and substituted aromatic hydrocarbons. The pyrolysis results were confirmed by oxidative thermal analysis which showed that the bulk of the carbon present was a macromolecular structure and not graphite. This suggests that an insoluble nongraphitic condensed aromatic polymer is indigenous to the meteorite. The origin and precise chemical structure of this material has not been determined, but it bears a superficial resemblance to coal-like structures.

Ki67 index in intracranial ependymoma: a promising histopathological candidate biomarker

AIMS

The Ki67 tumour cell proliferation index is an independent prognostic factor in ependymoma patients. Essential prerequisites for validation of the Ki67 index as a histopathological biomarker are the reproducibility of this factor and its prognostic influence by different observers (proof of objective clinical and analytical performance). To this end, the aim was to analyse systematically inter- and intraobserver agreement and reproducibility of the prognostic impact of the Ki67 index in intracranial ependymoma.

METHODS AND RESULTS

The study cohort contained 78 cases of intracranial ependymoma. In all cases, the Ki67 index was assessed by four experienced observers (EOs) and by four inexperienced observers (IOs) using the manual hot-spot method. There was considerable agreement on Ki67 index assessment. There was higher observer agreement among EOs compared with IOs. For each observer, survival analysis showed significant association of low Ki67 index with favourable patient outcome.

CONCLUSIONS

Our data show that the Ki67 index in intracranial ependymoma is a reproducible and robust prognostic factor and can be considered a promising histopathological candidate biomarker. Attainment of biomarker status requires further translational studies in the context of prospective therapeutic trials.

Analysis of MGMT promoter methylation status in high grade glioma patients with long term and conventional survival times: A retrospective study

2084

Background: Response to alkylating chemotherapy in patients with high grade gliomas (HGG) has been found correlated to epigenetic silencing of the DNA repair gene MGMT (O6-methylguanine-DNA methyltransferase) in the tumor tissue. Patients with HGG expressing a methylated MGMT promoter benefited from alkylating chemotherapy in terms of a prolonged survival as compared to patients with unmethylated MGMT promoter. Methods: Our study cohort comprised 47 patients with HGG, all treated with concomitant chemotherapy and radiotherapy in our institution. 23/47 patients (8 women, 15 men, aged 22.4–64.5 years, median 36.3) survived longer than 36 months (range of survival times 36–137 months, in median 46.9 months) and were defined as long term survivors (LS). 24/47 patients (5 women and 19 men, aged 18.3–73.3 years, median 47.7) with early tumor relapse who survived in median for 23.5 months were defined as HGG patients with conventional survival (CS). In all cases, we extracted DNA from formalin-fixed and paraffin-embedded tumor tissue samples. The methylation status of the MGMT promoter was determined by bisulfide modification of the DNA and methylation-specific polymerase-chain- reaction (MSP). MSP results were rated by 4 independent observers. Results: There was high interobserver agreement at interpretation of MSP results (range of kappa values: 0.71–0.87). Among LS, we found MGMT promoter methylation in 13/24 (81.5%) patients and an unmethylated MGMT promoter in 3 patients, whereas the MSP results were not interpretable in 7 patients of this patient subgroup. Among CS, we found promoter methylation in 16 patients (66.6%), unmethylated promoter in 6 patients and uninterpretable results in one patient. There was no statistically significant difference in MGMT promoter methylation rate between LS and CS. Conclusions: The proportion of gliomas with methylated MGMT promoter in this series is unexpectedly high, particularly for CS patients. Potential explanations for this finding are methodological differences due to the use of paraffin-embedded tumors instead of frozen tumor material as in most published series and a potential random accumulation of MGMT positive tumors in the patients with CS survival.

No significant financial relationships to disclose.

Conversion from subtypes of mild cognitive impairment to Alzheimer dementia

OBJECTIVE

To compare the rates of conversion to Alzheimer dementia (AD) between subtypes of mild cognitive impairment (MCI) in a community-based birth cohort investigated at age 75 and followed up after 30 months.

METHODS

The Vienna Trans-Danube Aging Study investigated every inhabitant of the area on the left shore of the river Danube who was born between May 1925 and June 1926. With use of the official voting registry, 1505 subjects were contacted and 697 participated. Data refer to the cohort of 581 nondemented individuals who completed extensive neuropsychological examination at baseline. Follow-up after 30 months was possible in 476 probands (35 deceased).

RESULTS

The 141 patients with MCI at baseline were classified into two subtypes. At follow-up, 41 of these patients with MCI were diagnosed with AD. Conversion rates to AD were 48.7% (CI: 32.4 to 65.2) for amnestic MCI and 26.8% (CI: 17.6 to 37.8) for nonamnestic MCI. Another 49 AD cases originated from cognitive health at baseline (12.6%; CI: 9.4 to 16.3).

CONCLUSIONS

Patients with mild cognitive impairment (MCI) showed a high probability to be diagnosed with Alzheimer dementia (AD) after 30 months. Subtypes of MCI were not useful in defining early stages of various types of dementia: Not only amnestic MCI but also nonamnestic MCI converted frequently to AD, and conversion to vascular dementia and dementia with Lewy bodies was not restricted to nonamnestic MCI.

Determinants of diagnostic investigation sensitivities across the clinical spectrum of sporadic Creutzfeldt-Jakob disease

To validate the provisional findings of a number of smaller studies and explore additional determinants of characteristic diagnostic investigation results across the entire clinical spectrum of sporadic Creutzfeldt-Jakob disease (CJD), an international collaborative study was undertaken comprising 2451 pathologically confirmed (definite) patients. We assessed the influence of age at disease onset, illness duration, prion protein gene (PRNP) codon 129 polymorphism (either methionine or valine) and molecular sub-type on the diagnostic sensitivity of EEG, cerebral MRI and the CSF 14-3-3 immunoassay. For EEG and CSF 14-3-3 protein detection, we also assessed the influence of the time point in a patient's illness at which the investigation was performed on the likelihood of a typical or positive result. Analysis included a large subset of patients (n = 743) in whom molecular sub-typing had been performed using a combination of the PRNP codon 129 polymorphism and the form of protease resistant prion protein [type 1 or 2 according to Parchi et al. (Parchi P, Giese A, Capellari S, Brown P, Schulz-Schaeffer W, Windl O, Zerr I, Budka H, Kopp N, Piccardo P, Poser S, Rojiani A, Streichemberger N, Julien J, Vital C, Ghetti B, Gambetti P, Kretzschmar H. Classification of sporadic Creutzfeldt-Jakob disease based on molecular and phenotypic analysis of 300 subjects. Ann Neurol 1999; 46: 224-233.)] present in the brain. Findings for the whole group paralleled the subset with molecular sub-typing data available, showing that age at disease onset and disease duration were independent determinants of typical changes on EEG, while illness duration significantly influenced positive CSF 14-3-3 protein detection; changes on brain MRI were not influenced by either of these clinical parameters, but overall, imaging data were less complete and consequently conclusions are more tentative. In addition to age at disease onset and illness duration, molecular sub-type was re-affirmed as an important independent determinant of investigation results. In multivariate analyses that included molecular sub-type, time point of the investigation during a patient's illness was found not to influence the occurrence of a typical or positive EEG or CSF 14-3-3 protein result. A typical EEG was most often seen in MM1 patients and was significantly less likely in the MV1, MV2 and VV2 sub-types, whereas VV2 patients had an increased likelihood of a typical brain MRI. Overall, the CSF 14-3-3 immunoassay was the most frequently positive investigation (88.1%) but performed significantly less well in the very uncommon MV2 and MM2 sub-types. Our findings confirm a number of determinants of principal investigation results in sporadic CJD and underscore the importance of recognizing these pre-test limitations before accepting the diagnosis excluded or confirmed. Combinations of investigations offer the best chance of detection, especially for the less common molecular sub-types such as MV2 and MM2.

Immunohistochemical analysis of platelet-derived growth factor receptor-alpha, -beta, c-kit, c-abl, and arg proteins in glioblastoma: possible implications for patient selection for imatinib mesylate therapy

Inhibition of tyrosine kinase (TK) receptors by synthetic small molecules has become a promising new therapy option in oncology. The TK inhibitor imatinib mesylate selectively targets PDGFR-alpha, -beta, c-kit, c-abl and arg and has proven successful in the treatment of chronic myeloid leukaemia. In recurrent glioblastoma, phase II therapy trials using imatinib mesylate have been initiated. As only a fraction of patients seems to benefit from imatinib mesylate therapy and due to potential side effects and high costs of imatinib mesylate therapy, selection of the right patients is important. The goal of our study was to assess systematically immunohistochemical expression of the major TKs targeted by imatinib mesylate in glioblastoma, as expression of these factors could be used to select patients for imatinib mesylate therapy. In a cohort of 101 glioblastoma patients, anti-PDGFR-alpha, -beta, c-kit, c-abl and arg protein immunohistochemistry was performed. Expression of these proteins was assessed semi-quantitatively and correlated with patient survival.PDGFR-alpha and arg expression in tumor cells was widespread in 1/101 cases, respectively. Focal PDGFR-alpha, -beta, c-kit, c-abl and arg immunolabeling was detected in 25/101, 19/101, 4/101, 7/101 and 31/101 cases, respectively. Statistical analysis did not reveal any correlation between expression of the TKs and patient survival. We show here for the first time in a large series of glioblastomas that PDGFR-alpha, -beta, c-kit, c-abl and arg expression is immunohistochemically detectable in a fraction of cases. The value of anti-tyrosine kinase immunolabeling as predictive factor for patient selection remains to be clarified by comparative analysis of tumor tissue of therapy-responders versus non-responders.

Alzheimer-type neuropathology in a 28 year old patient with iatrogenic Creutzfeldt-Jakob disease after dural grafting

We report the case of a 28 year old man who had received a cadaverous dura mater graft after a traumatic open skull fracture with tearing of the dura at the age of 5 years. A clinical suspicion of Creutzfeldt-Jakob disease (CJD) was confirmed by a brain biopsy 5 months prior to death and by autopsy, thus warranting the diagnosis of iatrogenic CJD (iCJD) according to WHO criteria. Immunohistochemistry showed widespread cortical depositions of disease associated prion protein (PrP(sc)) in a synaptic pattern, and western blot analysis identified PrP(sc) of type 2A according to Parchi et al. Surprisingly, we found Alzheimer-type senile plaques and cerebral amyloid angiopathy in widespread areas of the brain. Plaque-type and vascular amyloid was immunohistochemically identified as deposits of beta-A4 peptide. CERAD criteria for diagnosis of definite Alzheimer's disease (AD) were met in the absence of neurofibrillar tangles or alpha-synuclein immunoreactive inclusions. There was no family history of AD, CJD, or any other neurological disease, and genetic analysis showed no disease specific mutations of the prion protein, presenilin 1 and 2, or amyloid precursor protein genes. This case represents (a) the iCJD case with the longest incubation time after dural grafting reported so far, (b) the youngest documented patient with concomitant CJD and Alzheimer-type neuropathology to date, (c) the first description of Alzheimer-type changes in iCJD, and (d) the second case of iCJD in Austria. Despite the young patient age, the Alzheimer-type changes may be an incidental finding, possibly related to the childhood trauma.

New approaches in nuclear medicine for early diagnosis of Alzheimer's disease

Dementia, Alzheimer's disease (AD) being the most common cause of it, is a major and growing medical and social problem, particularly in the advanced age, with the highest rate in the population over 75 y. Recent sophisticated therapeutic measures require more sensitive diagnostic tests to recognize early stages of the disease. In this paper, the current neuronuclear imaging literature is reviewed with regard to early and differential diagnosis of dementia. Functional imaging with single photon emission computed tomography (SPECT) and positron emission tomography (PET) could provide the clinician with additional information complementary to morphological assessments, thus contributing to achieve a more adequate diagnosis, and also with information regarding prodromal stages of AD.

Predictors of survival in sporadic Creutzfeldt-Jakob disease and other human transmissible spongiform encephalopathies

A collaborative study of human transmissible spongiform encephalopathies has been carried out from 1993 to 2000 and includes data from 10 national registries, the majority in Western Europe. In this study, we present analyses of predictors of survival in sporadic (n = 2304), iatrogenic (n = 106) and variant Creutzfeldt-Jakob disease (n = 86) and in cases associated with mutations of the prion protein gene (n = 278), including Gerstmann-Sträussler-Scheinker syndrome (n = 24) and fatal familial insomnia (n = 41). Overall survival for each disease type was assessed by the Kaplan-Meier method and the multivariate analyses by the Cox proportional hazards model. In sporadic disease, longer survival was correlated with younger age at onset of illness, female gender, codon 129 heterozygosity, presence of CSF 14-3-3 protein and type 2a prion protein type. The ability to predict survival based on patient covariates is important for diagnosis and counselling, and the characterization of the survival distributions, in the absence of therapy, will be an important starting point for the assessment of potential therapeutic agents in the future.

Ischemic preconditioning: a defense mechanism against the reactive oxygen species generated after hepatic ischemia reperfusion

BACKGROUND

Preconditioning protects against both liver and lung damage after hepatic ischemia-reperfusion (I/R). Xanthine and xanthine oxidase (XOD) may contribute to the development of hepatic I/R.

OBJECTIVE

To evaluate whether preconditioning could modulate the injurious effects of xanthine/XOD on the liver and lung after hepatic I/R.

METHODS

Hepatic I/R or preconditioning previous to I/R was induced in rats. Xanthine and xanthine dehydrogenase/xanthine oxidase (XDH/XOD) in liver and plasma were measured. Hepatic injury and inflammatory response in the lung was evaluated.

RESULTS

Preconditioning reduced xanthine accumulation and conversion of XDH to XOD in liver during sustained ischemia. This could reduce the generation of reactive oxygen species (ROS) from XOD, and therefore, attenuate hepatic I/R injury. Inhibition of XOD prevented postischemic ROS generation and hepatic injury. Administration of xanthine and XOD to preconditioned rats led to hepatic MDA and transaminase levels similar to those found after hepatic I/R. Preconditioning, resulting in low circulating levels of xanthine and XOD activity, reduced neutrophil accumulation, oxidative stress, and microvascular disorders seen in lung after hepatic I/R. Inhibition of XOD attenuated the inflammatory damage in lung after hepatic I/R. Administration of xanthine and XOD abolished the benefits of preconditioning on lung damage.

CONCLUSIONS

Preconditioning, by blocking the xanthine/XOD pathway for ROS generation, would confer protection against the liver and lung injuries induced by hepatic I/R.

Automated strong cation exchange extraction of fatty acid esters of 3-(N-phenylamino)-1,2-propanediol from oil samples for routine quantification by HPLC-APCI/MS/MS

Fatty acid esters of 3-(N-phenylamino)-1,2-propanediol are currently considered the best chemical markers of toxic oils related to the Spanish toxic oil syndrome. Recent research in this area has undertaken the exhaustive and quantitative characterization of these compounds in oils collected during the epidemic outbreak. Current methods developed in this laboratory are based on solid phase extraction (SPE) using SCX cartridges followed by HPLC-APCI/MS/MS quantification. To circumvent the long and tedious extraction procedure, the SPE protocol was adapted for automatic extraction and the problems derived from the use of the immiscible solvents required for the SCX extraction were solved. Linearity of the analytical method was found in the same range as for the manual method. Extraction recoveries were 87 and 75% for 2-hydroxy-3-(N-phenylamino)propyl linoleate and 2-(linoleyloxy)-3-(N-phenylamino)propyl linoleate, respectively, and the corresponding coefficients of variation were approximately 1%, greatly improving reproducibility over manual procedures.

Determination of aniline derivatives in oils related to the toxic oil syndrome by atmospheric pressure ionization-tandem mass spectrometry

In 1981, an unknown disease appeared in Spain, the Spanish Toxic Oil Syndrome. Nowadays and despite all efforts, the etiological agent is still unknown. Early studies showed a link between this illness and the consumption of denatured rapeseed oil fraudulently processed and marketed as edible oil. Two families of aniline derivatives present in these oils (fatty acid anilides and acylated phenyl amino propanediol derivatives or PAPs) were found to be good chemical markers of toxic oils. In this work, a new method has been developed to analyze these aniline derivatives in oil samples by HPLC-MS and HPLC-MS/MS with an API source. For their quantification, three different internal standards were used, one for anilides and two for PAPs. Quantification limits were 8 ppm for anilides and 0.2 ppm for PAPs. Anilides and PAPs were found in marker-positive samples at levels up to 50,000 and 330 ppm, respectively. The relative abundance of the different fatty acid anilides and PAPs correlates with the fatty acid composition of the oils. More than 2,600 different samples were analyzed by this method in the most exhaustive screening of suspected toxic oils carried out to date.

International Mass Spectrometry Society (IMSS)

This paper gives a brief description of the recently formalized International Mass Spectrometry Society (IMSS). It is presented here in order to increase awareness of the opportunities for collaboration in mass spectrometry in an international context. It also describes the recent 15th International Mass Spectrometry Conference, held August/September 2000, in Barcelona. Each of the authors is associated with the IMSS. The 15th Conference, which covers all of mass spectrometry on a triennial basis, was chaired by Professor Emilio Gelpi of the Instituto de Investigaciones Biomedicas, Barcelona. The outgoing and founding President of the IMSS is Professor Graham Cooks, Purdue University, and the incoming President is Professor Nico Nibbering, University of Amsterdam. Similar material has been provided to the Editors of other journals that cover mass spectrometry.

Effect of ozone treatment on reactive oxygen species and adenosine production during hepatic ischemia-reperfusion

This study investigates whether ozone could confer protection from hepatic ischemia reperfusion by modifying the accumulation of adenosine and xanthine during ischemia. A significant increase in both adenosine and xanthine accumulation was observed as a consequence of ATP degradation during hepatic ischemia. Adenosine exerts a protective effect on hepatic ischemia reperfusion injury since the elimination of endogenous adenosine accumulation with adenosine deaminase increased the hepatic injury associated with this process. On the other hand, the high xanthine levels observed after ischemia could exert deleterious effects during reperfusion due to reactive oxygen species generation from xanthine oxidase. The administration of allopurinol, an inhibitor of xanthine oxidase, attenuated the increase in reactive oxygen species and transaminase levels observed after hepatic reperfusion. Ozone treatment in liver maintained adenosine levels similar to those found after ischemia but led to a marked reduction in xanthine accumulation. In order to evaluate the role of both adenosine and xanthine, we tried to modify the protection confered by ozone, by modifying the concentrations of adenosine and xanthine. The metabolization of endogenous adenosine after ischemia abolished the protective effect conferred by ozone. When xanthine was administered previous to ozone treatment, the protection conferred by adenosine disappeared, showing both postischemic reactive oxygen species and transaminase levels similar to those found after hepatic ischemia reperfusion. Ozone would confer protection against the hepatic ischemia reperfusion injury by the accumulation of adenosine that in turns benefits the liver and by blocking the xanthine/xanthine oxidase pathway for reactive oxygen species generation.

P-selectin expression and Kupffer cell activation in rat acute pancreatitis

This work studied the activation of hepatic macrophages during acute pancreatitis and the involvement of these cells in the lung inflammatory response. Pancreatitis was induced in Wistar rats by intraductal administration of 5% sodium taurocholate. Three hours after pancreatitis induction, the degree of pulmonary inflammation, TNF-alpha levels, and P-selectin expression were evaluated. The generation of TNF-alpha by Kupffer cells was also measured. Pancreatitis increases the serum concentration of TNF-alpha, neutrophil infiltration, and P-selectin expression in pancreas and lung. In addition, Kupffer cells generate increased levels of TNF-alpha. When Kupffer cells were inhibited, the increase in serum TNF-alpha levels and the infiltration of neutrophils in the lung were prevented, but P-selectin expression remained unmodified. We conclude that pulmonary inflammation induced by acute pancreatitis is mediated by Kupffer cell activation and that pancreatitis induces the expression of P-selectin on pulmonary endothelial cells but this effect is not mediated by Kupffer cells.

Modification of oxidative stress in response to intestinal preconditioning

Previous studies have demonstrated that intestinal preconditioning protects the organ from ischemia reperfusion damage. Xanthine oxidase mediating free radical generation contributes to the development of injury associated to ischemia reperfusion. Thus, any process able to modulate the oxygen free radical generation system could attenuate the injury. Also, it is known that nitric oxide is implicated in the preconditioning response. The aim of this work is to determine: (1) the effect of intestinal preconditioning on the xanthine oxidase system, (2) the relevance of this system in the development of injury, and (3) its relationship with nitric oxide. For this purpose, we have determined the activity of the xanthine dehydrogenase/xanthine oxidase system, the levels of its substrate (xanthine), and end-product (uric acid) and oxidant stress status in rat small intestine subjected to ischemic pre-conditioning. The effects of nitric oxide inhibition have also been evaluated. Results show that the percentage of xanthine dehydrogenase to xanthine oxidase conversion, xanthine, uric acid concentration, lipoperoxides, and reduced glutathione were significantly reduced in preconditioned rats irrespectively of nitric oxide inhibition. In summary, this work shows that oxidative stress in intestinal preconditioning is reduced as consequence of the diminished conversion of xanthine dehydrogenase to xanthine oxidase, and also as a consequence of the reduced availability of xanthine.

Evolution of streptozotocin-pancreatic damage in the rat: modulatory effect of endothelins on the nitridergic and prostanoid pathway

Many lines of evidence indicate that an increased pancreatic production of nitric oxide (NO) and prostaglandins (PGs) is found in the pancreas of streptozotocin-diabetic rats and that endothelins (ETs) are closely related to the nitridergic and prostanoid pathway in several tissues. In the present study the relationship between NO, ETs, and PGs has been explored in isolated pancreatic tissue from streptozotocin-diabetic rats. Pancreatic ET levels are higher in pancreatic tissues from diabetic (D) rats compared to control (C) animals. The addition of nitric oxide synthase (NOS) inhibitors (1 mM N(G)-nitro-l-arginine methyl ester, 600 microM N(G)-monomethyl-l-arginine) in the incubating medium reduces and NO donors (SIN-1, 300 microM spermine suppress, NONOate 100 microM) increases ET levels in pancreatic slices from C and D animals. PGE(2) (10(-7) M) increases and indomethacin (10(-6) M) decreases ET pancreatic production only in D but not in C tissues when added into the incubating bath. When tissues are incubated in the presence of endothelin 1 (ET-1) (10(-7) M), NOS activity is higher in C pancreas, while the ET-receptor antagonist bosentan (B) decreases NOS levels in D but not in C tissues. When pancreatic arachidonic acid (AA) conversion to prostaglandins was explored, ET-1 increased PGF(2alpha), PGE(2), and TXB(2) levels in C but not in D tissues. B abolishes TXB(2) increment due to the diabetic state, but failed in modulating AA conversion to 6-keto PGF(1alpha), PGF2(alpha) and PGE(2) in D pancreas. Our results show an alteration in AA metabolism, ET production, and NO increment associated with pancreatic damage due to streptozotocin.

Urinary biomarkers as indicators of renal disease

Using modern technology, minute quantities of LMWP, prostanoids, growth factors, intra-renal and extra-renal enzymes can be measured in urine. Excretory patterns that are characteristic for site and mechanism of renal injury often can be found. It is possible to recognise urinary biomarker patterns that suggest the putative environmental nephrotoxin. Our own studies performed in subjects with low level occupational and environmental exposures in New Jersey confirm the pattern specificity and threshold effects for Cr, Hg and Pb. In addition, we have been able to show that increased NAG and IAP excretion following Pb exposure correlates with current (blood Pb) but not with the cumulative Pb burden (bone Pb). The relatively specific characteristic patterns of biomarker excretion are lost as renal failure progresses. Moreover, renal injury that results in tubular proteinuria may not progress to renal failure. Nevertheless, urine biomarkers can help to establish acceptable levels and identify the need for long term surveillance to ascertain when clinical renal disease may result.

Endothelin mediated nitric oxide effects in ischemia--reperfusion associated with pancreas transplantation

Formation of nitric oxide (NO) in ischemia-reperfusion (I-R) associated with pancreas transplantation could modulate the inflammatory response. In this sense, previous studies have demonstrated the action of NO on vasoactive substances like prostacyclin or endothelin. The present study was designed to evaluate the contribution of endothelin to the inflammatory events induced by NO in the I-R process associated with pancreas transplantation. For this purpose, pancreatic levels of endothelin, neutrophil infiltration, and prostacyclin were evaluated in an experimental model of pancreas transplantation after inhibition of NO synthesis or after NO inhibition plus addition of endothelin. Results show significant posttransplantation increases in endothelin, neutrophil infiltration, and prostacyclin production. These increases were prevented by NO inhibition. Endothelin administration plus nitric oxide inhibition reversed this effect, resulting in an increase in myeloperoxidase and 6-keto-prostaglandin F1alpha. These results suggest that the proinflammatory effects of NO in I-R associated with pancreas transplantation are mediated by the induction of endothelin generation.

Adverse effects of chronic low level lead exposure on kidney function--a risk group study in children

BACKGROUND

Children have been considered a risk group for lead (Pb) toxicity, mainly because of neurophysiological or neuro-cognitive deficits following Pb exposure. Blood Pb levels (b-Pb) of 100 microg/l currently have been defined as the lowest adverse effect level. The aim of this study was to compare, with the help of urinary markers, the kidney function of children with b-Pb just above this threshold with that of unexposed children, to assess from a nephrological point of view whether the current threshold is justified and whether children really are a particularly vulnerable risk group in terms of Pb-induced kidney damage.

METHODS

In a cross-sectional study, 112 children, either from unexposed areas (controls, n=50) or Pb-contaminated areas (n=62), the latter partly with a known history of elevated b-Pb, were examined. Twenty nine urinary or serum markers mostly related to the function or integrity of specific nephron segments were determined (e.g. filtered plasma proteins, tubular enzymes, tubular antigens, eicosanoids).

RESULTS

b-Pb were 39+/-13 microg/l in controls and 133+/-62 microg/l in exposed children. The main findings were increased excretion rates of prostaglandins and thromboxane B2, epidermal growth factor, beta2-microglobulin and Clara cell protein in the exposed children. A relationship between b-Pb and the prevalence of values above the upper reference limits was observed.

CONCLUSIONS

With the help of urinary markers, nephron segment-specific effects of chronic low-level Pb exposure could be detected in children. The pattern of effects on glomerular, proximal and distal tubular and interstitial markers was similar to that previously observed in adults. The changes, however, occur at lower b-Pb levels than in adults. The current threshold appears to be justified also from a nephrological point of view, and children can indeed be considered a special risk group.

The assessment of biomarkers to detect nephrotoxicity using an integrated database

Groups of industrial workers exposed to heavy metals (cadmium, mercury, and lead) or solvents were studied together with corresponding control groups. The cohorts were collected from several European centers (countries). Eighty-one measurements were carried out on urine, blood, and serum samples and the results of these analyses together with questionnaire information on each individual were entered into a central database using the relational database package Rbase. After the completion of the database construction phase, the data were exported in a format suitable for analysis by the statistical package SAS. The potential value of each test as an indicator of nephrotoxicity was then assessed. Rigorous exclusion criteria were applied which resulted in the elimination of some tests and samples from the dataset. The measurable contributions of smoking, gender, metal exposure, and site were either singly or in combination assessed by biomarkers for nephrotoxicity. The parameters measured included three urinary enzymes, six specific proteins, total protein, two extracellular matrix markers, four prostaglandins and anti-GBM antibodies, and beta 2-microglobulin in serum. The most sensitive renal tests included the urinary enzymes N-acetyl-beta-D-glucosaminidase (NAG) and intestinal alkaline phosphatase (IAP), brush border antigens, and urinary low-molecular-weight proteins. Of the newer tests investigated the prostaglandins were the most promising. Different patterns of biomarker excretion were observed following exposure to lead, cadmium, or mercury. The dataset provides a unique repository of data which could provide the basis of an enlarging source of information on normal human reference ranges and on the effects of exposure to toxins and the use of biomarkers for monitoring nephrotoxicity.

Differential effect of nitric oxide inhibition as a function of preservation period in pancreas transplantation

The role of nitric oxide, produced during reperfusion as a function of preservation time, in the development of the inflammatory process in pancreas transplantation has been explored. For this purpose, the effect of nitric oxide synthase inhibition, as well as 6-keto-prostaglandin F1alpha, leukotriene B4, and lipoperoxidation levels were evaluated in an experimental model of rat pancreas transplantation after different periods of cold preservation. The results show posttransplantation increases in 6-keto-prostaglandin F1alpha, leukotriene B4, and lipoperoxidation levels in pancreatic tissue and in plasma lipase. When ischemia was induced for 30 min, nitric oxide synthase inhibition prevented these increases, and L-arginine was able to reverse this effect. By contrast, nitric oxide synthase inhibition has no effect when ischemia was prolonged for 12 hr. In summary, this study suggests that, during reperfusion, nitric oxide modulates 6-keto-prostaglandin F1alpha synthesis, lipoperoxidation levels, and the development of pancreatic injury but only when the ischemic period is quite short.

Eicosanoid production, metabolism and contractile activity in the isolated uterus from non-insulin-dependent diabetic rats during late pregnancy

Eicosanoid production, glucose (Glu), glycogen (Gly) and triglyceride (TG) metabolism, spontaneous contractile activity, PGF2 alpha and oxytocin-induced contractions have been studied in uterine tissue obtained from control (C) and non-insulin-dependent diabetic (D) rats prior to parturition. Parturition occurs on day 22 of gestation in control animals, whereas a 24 hr delay was observed in diabetic rats. Production of PGE2, PGE1, 6-keto-PGF1 alpha, PGF2 alpha, TXB2 and LTB4 was similar in uterine tissue obtained from control and diabetic rats on day 21 of pregnancy. Uterine metabolism, on day 21 of pregnancy, based on the production of 14CO2 from U14C-glucose was lower in tissues obtained from diabetic rats than in controls. Levels of TG were similar at 0 hr and after 60 min incubation in Glu or Glu-free medium in both experimental groups. Initially Gly levels in diabetic and control uteri were similar. After 60 minutes of incubation, levels of Gly in control tissue decreased only in the absence of Glu in the incubation medium. In contrast, in diabetic uterine strips, levels of Gly decreased after 60 minutes of incubation either in Glu or Glu-free medium. "In vitro" isometric-developed tension (IDT) evaluated on day 21 (C and D) and 22 (D) of pregnancy was similar at 0 hr in control and diabetic uterine preparations, but IDT in both diabetic groups was decreased after a 40 minute incubation when compared to controls. Alterations in PGF2 alpha-induced uterine responses were not seen in 21 or 22 days pregnant diabetic uterine tissue when compared to controls. In contrast, impaired oxytocin responses were observed in diabetic uteri on day 21 of gestation, but they were similar to control responses of uterine tissue from day 22 diabetic rats. We conclude that in the non-insulin-dependent late pregnant rat, there are no alterations in uterine tissue eicosanoid production, but metabolic and contractile abnormalities are present. Involvement of these alterations in the delayed initiation of parturition is discussed.

Calcium channel blockers in experimental acute pancreatitis: effect on tissue prostanoids and oxygen free radicals

The effect of verapamil administration on the changes of prostanoid synthesis, and on free radical production associated with acute pancreatitis, has been evaluated. A necrohemorrhagic model of pancreatitis was induced in Wistar rats by intraductal administration of sodium taurocholate (3.5%). This model is associated with initial increases in prostanoid synthesis and peroxidative damage. Verapamil, administered before pancreatitis induction, prevented initial increases in 6-keto prostaglandin F1alpha (PGF1alpha) and thromboxane B2 (TXB2) but had no effect on PGF2alpha or PGE2 or on lipoperoxidative damage. These results indicate that verapamil administration prevents the increases in pancreatic vasoactive prostanoids (TXB2 and 6-keto PGF1alpha) without affecting the increased levels of PGE2 and PGF2alpha and has no effect on oxygen free radical production in the initial stages of experimental acute pancreatitis.

Development and validation of new screening tests for nephrotoxic effects

Within the framework of an European Commission-funded project, groups of industrial workers exposed to heavy metals (cadmium, mercury and lead) or solvents were studied together with corresponding control groups. Eighty-one measurements were carried out on urine and serum samples and the scientific results together with individual questionnaire information were entered into a central database. Data obtained was assessed centrally and individually in subsidiary studies. The measurable contributions were assessed either singly or in combination, of smoking, gender, metal exposure and site, to nephrotoxicity. The potential value of each test as an indicator of nephrotoxicity was then assessed on the basis of sensitivity and specificity. A number of new tests including prostaglandins and for extracellular matrix components were investigated as well as established tests for renal damage and dysfunction. The data obtained from this comprehensive study emphasises the value of noninvasive biomarkers for the early detection of nephrotoxicity due to environmental toxins. The urinary profile varied with the type of environmental/occupational toxin. By careful selection of a small panel of markers they can be used to indicate the presence of renal damage, the principal region affected, and to monitor the progress of disease and damage. Biomarkers were also used to confirm and tentatively establish safe exposure levels to nephrotoxins.

Eicosanoid production and phospholipase A2 activity in uterine tissue from castrated rats with non-insulin dependent diabetes mellitus

In uterine tissue obtained from castrated control and non-insulin dependent diabetic (NIDDM) rats, eicosanoid production and its regulation by glucose levels and by the activity of phospholipase A2 (PLA2) was assessed. Basal outputs of prostaglandins (PGs) PGE2, PGE1, PGF2 alpha, 6-keto-PGF1 alpha (indicating the production of prostacyclin), thromboxane B2 (TXB2) (indicating the generation of TXA2) and leukotriene B4 (LTB4) were similar in control and NIDDM uterine preparations as assessed by RIA. When uterine conversion of labelled arachidonate into different prostanoids was evaluated, generation of 6-keto-PGF1 alpha, PGE2 and PGF2 alpha was similar in control and NIDDM uterine tissue, while TXB2 production was higher in the diabetic group. Moreover, when control tissue was incubated in the presence of elevated concentrations of glucose (22 mM) and compared to control tissue incubated in concentrations of glucose 11 mM, similar generation of 6-keto-PGF1 alpha, PGE2 and PGF2 alpha was observed, and higher concentrations of TXB2 were found, similar to those observed in diabetic uterine tissue. When NIDDM uterine tissue was incubated in the presence of glucose 22 mM, no difference in any prostanoid evaluated was observed when compared to values obtained in the presence of glucose 11 mM. In this work we have observed in NIDDM uterine tissue a normal TXA2 production when evaluated by RIA from endogenous arachidonic acid (AA) and a higher TXA2 generation from exogenous labelled AA. In addition PLA2 activity was found diminished in the NIDDM uteri in comparison to control uteri. A role of the diminished PLA2 as a protective mechanism that avoids TXA2 overproduction in uterine tissue from NIDDM rats is discussed.

Prostanoids and oxygen free radicals in early stages of experimental acute pancreatitis

The aim of this work is to establish a relationship between prostanoids and oxygen free radicals in the early stages of acute pancreatitis induced by sodium taurocholate and to study the possible cytoprotective effects of exogenous prostaglandin administration. Tissue prostanoid production (6-keto-prostaglandin F1 alpha, thromboxane B2, and prostaglandin E2) was studied after induction of an acute pancreatitis by intraductal administration of 3.5% sodium taurocholate (0.1 ml/100 mg). The effect of previous administrations of 16,16-dimethyl prostaglandin E2 (0.5 microgram/kg), indomethacin (20 mg/kg), or superoxide dismutase (13 mg/kg) was evaluated. Early pancreatitis induced significant increases of the three prostanoid levels as soon as 5 min after taurocholate administration. The administration of 16,16-dimethyl prostaglandin E2 was able to maintain the tissue prostanoid production at basal levels while superoxide dismutase treatment only partially prevented the increase of 6-keto-prostaglandin F1 alpha. On the other hand, indomethacin pretreatment, as expected, prevented the taurocholate-induced early prostanoid biosynthesis but increased the mortality, suggesting that endogenous prostanoids play a role in cellular defense mechanisms. The effect of superoxide dismutase suggests that oxygen free radicals are responsible, in part, for prostanoid enhanced biosynthesis in the earlier stages of necrohemorrhagic pancreatitis.