Quantitative uptake in 99m Tc-EDDA/HYNIC-TOC somatostatin receptor imaging - the effect of long-acting release somatostatin analogue therapy.

PURPOSE: Withdrawal of long-acting release somatostatin analogue (LAR-SSA) treatment before somatostatin receptor imaging is based on empirical reasoning that it may block uptake at receptor sites. This study aims to quantify differences in uptake of 99m Tc-EDDA/HYNIC-TOC between patients receiving LAR-SSA and those who were not. METHODS: Quantification of 177 patients (55 on LAR-SSA) imaged with 99m Tc-EDDA/HYNIC-TOC was performed, with analysis of pathological tissue and organs with physiological uptake using thresholded volumes of interest. Standardised uptake values (SUVs) and tumour/background (T/B) ratios were calculated and compared between the two patient groups. RESULTS: SUVs were significantly lower for physiological organ uptake for patients on LAR-SSA (e.g. spleen: SUV max 13.3 ±â€…5.9 versus 33.9 ±â€…9.0, P  < 0.001); there was no significant difference for sites of pathological uptake (e.g. nodal metastases: SUV max 19.2 ±â€…13.0 versus 17.4 ±â€…11.5, P  = 0.552) apart from bone metastases (SUV max 14.1 ±â€…13.5 versus 7.7 ±â€…8.0, P  = 0.017) where it was significantly higher. CONCLUSION: LAR-SSA has an effect only on physiological organ uptake of 99m Tc-EDDA/HYNIC-TOC, reducing uptake. It has no significant effect on pathological uptake for most sites of primary and metastatic disease. This should be taken into account if making quantitative measurements, calculating T/B ratios or assigning Krenning Scores. There is the potential for improved dosimetric results in Peptide Receptor Radionuclide Therapy by maintaining patients on LAR-SSA.

Liver transplantation for hereditary hemorrhagic telangiectasia: Report of the European liver transplant registry.

BACKGROUND: Hereditary hemorrhagic telangiectasia (HHT) or Rendu-Osler-Weber disease is a rare disease characterized by the presence of arteriovenous malformations. Hepatic involvement can lead to life-threatening conditions. MATERIAL AND METHODS: Forty patients, reported to the European Liver Transplant Registry, were analyzed to define the role of liver transplantation in the treatment of the hepatic disease form. Indications for transplantation were classified according to Garcia-Tsao: cardiac failure (14 patients), biliary necrosis causing hepatic failure (12 patients), severe portal hypertension (5 patients), cardiac failure and biliary necrosis (6 patients), cardiac failure and portal hypertension (2 patients), and cardiac failure associated with biliary necrosis and portal hypertension (1 patient). Eighteen (81%) of 22 patients had pulmonary artery hypertension. Twelve (30%) patients had pretransplant hepatic interventions. Follow-up was complete for all patients with a mean of 69 months (range, 0-230 months). RESULTS: One-, 5- and 10-year actuarial patient and graft survival rates are 82.5%. Six of the 7 pretransplant procedures performed on the hepatic artery were severely complicated. Cardiovascular function documented in 24 patients improved in 18 patients and remained stable in 5 patients; 1 patient died perioperatively of acute heart failure. Twenty-four (60%) patients had post-transplant complications, all but one occurring within the first 4 posttransplant months. Seven (17.5%) patients died perioperatively, 6 of them due to bleeding and 1 due to cardiac failure; 1 (2.5%) patient died late due to chronic rejection. There were 2 possible recurrences. Quality of life markedly improved in all 32 surviving patients. CONCLUSION: The results of the largest reported transplant series in the treatment of hepatic-based HHT are excellent. Elimination of hepatobiliary sepsis and reversal of cardiopulmonary changes dramatically improve quality of life of the recipients. LT should be proposed earlier in the course of symptomatic hepatic HHT presenting with life-threatening conditions. Palliative interventions, especially on the hepatic artery, should be avoided in view of their high (infectious) complication rate.

Processing the noun phrase versus sentence coordination ambiguity: thematic information does not completely eliminate processing difficulty.

When faced with the noun phrase (NP) versus sentence (S) coordination ambiguity as in, for example, The thief shot the jeweller and the cop ..., readers prefer the reading with NP-coordination (e.g., "The thief shot the jeweller and the cop yesterday") over one with two conjoined sentences (e.g., "The thief shot the jeweller and the cop panicked"). A corpus study is presented showing that NP-coordinations are produced far more often than S-coordinations, which in frequency-based accounts of parsing might be taken to explain the NP-coordination preference. In addition, we describe an eye-tracking experiment investigating S-coordinated sentences such as Jasper sanded the board and the carpenter laughed, where the poor thematic fit between carpenter and sanded argues against NP-coordination. Our results indicate that information regarding poor thematic fit was used rapidly, but not without leaving some residual processing difficulty. This is compatible with claims that thematic information can reduce but not completely eliminate garden-path effects.

The cascaded nature of lexical selection and integration in auditory sentence processing.

An event-related brain potential experiment was carried out to investigate the temporal relationship between lexical selection and the semantic integration in auditory sentence processing. Participants were presented with spoken sentences that ended with a word that was either semantically congruent or anomalous. Information about the moment in which a sentence-final word could uniquely be identified, its isolation point (IP), was compared with the onset of the elicited N400 congruity effect, reflecting semantic integration processing. The results revealed that the onset of the N400 effect occurred prior to the IP of the sentence-final words. Moreover, the factor early or late IP did not affect the onset of the N400. These findings indicate that lexical selection and semantic integration are cascading processes, in that semantic integration processing can start before the acoustic information allows the selection of a unique candidate and seems to be attempted in parallel for multiple candidates that are still compatible with the bottom-up acoustic input.

Anticipating upcoming words in discourse: evidence from ERPs and reading times.

The authors examined whether people can use their knowledge of the wider discourse rapidly enough to anticipate specific upcoming words as a sentence is unfolding. In an event-related brain potential (ERP) experiment, subjects heard Dutch stories that supported the prediction of a specific noun. To probe whether this noun was anticipated at a preceding indefinite article, stories were continued with a gender-marked adjective whose suffix mismatched the upcoming noun's syntactic gender. Prediction-inconsistent adjectives elicited a differential ERP effect, which disappeared in a no-discourse control experiment. Furthermore, in self-paced reading, prediction-inconsistent adjectives slowed readers down before the noun. These findings suggest that people can indeed predict upcoming words in fluent discourse and, moreover, that these predicted words can immediately begin to participate in incremental parsing operations.

ERP effects of subject-verb agreement violations in patients with Broca's aphasia.

This article presents electrophysiological data on on-line syntactic processing during auditory sentence comprehension in patients with Broca's aphasia. Event-related brain potentials (ERPs) were recorded from the scalp while subjects listened to sentences that were either syntactically correct or contained violations of subject-verb agreement. Three groups of subjects were tested: Broca patients (n = 10), nonaphasic patients with a right-hemisphere (RH) lesion (n = 5), and healthy aged-matched controls (n = 12). The healthy, control subjects showed a P600/SPS effect as response to the agreement violations. The nonaphasic patients with an RH lesion showed essentially the same pattern. The overall group of Broca patients did not show this sensitivity. However, the sensitivity was modulated by the severity of the syntactic comprehension impairment. The largest deviation from the standard P600/SPS effect was found in the patients with the relatively more severe syntactic comprehension impairment. In addition, ERPs to tones in a classical tone oddball paradigm were also recorded. Similar to the normal control subjects and RH patients, the group of Broca patients showed a P300 effect in the tone oddball condition. This indicates that aphasia in itself does not lead to a general reduction in all cognitive ERP effects. It was concluded that deviations from the standard P600/SPS effect in the Broca patients reflected difficulties with on-line maintaining of number information across clausal boundaries for establishing subject-verb agreement.

When and how do listeners relate a sentence to the wider discourse? Evidence from the N400 effect.

In two ERP experiments, we assessed the impact of discourse-level information on the processing of an unfolding spoken sentence. Subjects listened to sentences like Jane told her brother that he was exceptionally quick/slow, designed such that the alternative critical words were equally acceptable within the local sentence context. In Experiment 1, these sentences were embedded in a discourse that rendered one of the critical words anomalous (e.g. because Jane's brother had in fact done something very quickly). Relative to the coherent alternative, these discourse-anomalous words elicited a standard N400 effect that started at 150-200 ms after acoustic word onset. Furthermore, when the same sentences were heard in isolation in Experiment 2, the N400 effect disappeared. The results demonstrate that our listeners related the unfolding spoken words to the wider discourse extremely rapidly, after having heard the first two or three phonemes only, and in many cases well before the end of the word. In addition, the identical nature of discourse- and sentence-dependent N400 effects suggests that from the perspective of the word-elicited comprehension process indexed by the N400, the interpretive context delineated by a single unfolding sentence and a larger discourse is functionally identical.

Event-related brain potentials reflect discourse-referential ambiguity in spoken language comprehension.

In two experiments, we explored the use of event-related brain potentials to selectively track the processes that establish reference during spoken language comprehension. Subjects listened to stories in which a particular noun phrase like "the girl" either uniquely referred to a single referent mentioned in the earlier discourse, or ambiguously referred to two equally suitable referents. Referentially ambiguous nouns ("the girl" with two girls introduced in the discourse context) elicited a frontally dominant and sustained negative shift in brain potentials, emerging within 300-400 ms after acoustic noun onset. The early onset of this effect reveals that reference to a discourse entity can be established very rapidly. Its morphology and distribution suggest that at least some of the processing consequences of referential ambiguity may involve an increased demand on memory resources. Furthermore, because this referentially induced ERP effect is very different from that of well-known ERP effects associated with the semantic (N400) and syntactic (e.g., P600/SPS) aspects of language comprehension, it suggests that ERPs can be used to selectively keep track of three major processes involved in the comprehension of an unfolding piece of discourse.

Syntax-related ERP-effects in Dutch.

In two studies subjects were required to read Dutch sentences that in some cases contained a syntactic violation, in other cases a semantic violation. All syntactic violations were word category violations. The design excluded differential contributions of expectancy to influence the syntactic violation effects. The syntactic violations elicited an Anterior Negativity between 300 and 500 ms. This negativity was bilateral and had a frontal distribution. Over posterior sites the same violations elicited a P600/SPS starting at about 600 ms. The semantic violations elicited an N400 effect. The topographic distribution of the AN was more frontal than the distribution of the classical N400 effect, indicating that the underlying generators of the AN and the N400 are, at least to a certain extent, non-overlapping. Experiment 2 partly replicated the design of Experiment 1, but with differences in rate of presentation and in the distribution of items over subjects, and without semantic violations. The word category violations resulted in the same effects as were observed in Experiment 1, showing that they were independent of some of the specific parameters of Experiment 1. The discussion presents a tentative account of the functional differences in the triggering conditions of the AN and the P600/SPS.

Lexical processing of vocabulary class in patients with Broca's aphasia: an event-related brain potential study on agrammatic comprehension.

This paper presents electrophysiological evidence of an impairment in the on-line processing of word class information in patients with Broca's aphasia with agrammatic comprehension. Event-related brain potentials (ERPs) were recorded from the scalp while Broca patients and non-aphasic control subjects read open- and closed-class words that appeared one at a time on a PC screen. Separate waveforms were computed for open- and closed-class words. The non-aphasic control subjects showed a modulation of an early left anterior negativity in the 210-325ms as a function of vocabulary class (VC), and a late left anterior negative shift to closed-class words in the 400-700ms epoch. An N400 effect was present in both control subjects and Broca patients. We have taken the early electrophysiological differences to reflect the first availability of word-category information from the mental lexicon. The late differences can be related to post-lexical processing. In contrast to the control subjects, the Broca patients showed no early VC effect and no late anterior shift to closed-class words. The results support the view that an incomplete and/or delayed availability of word-class information might be an important factor in Broca's agrammatic comprehension.