Revisiting the oddball paradigm. Non-target vs neutral stimuli and the evaluation of ERP attentional effects.

We recorded topographic mapping of auditory evoked potentials (AEPs) to homogeneous series of tones delivered in the absence of any cognitive task ("neutral condition") and compared them with responses to identical stimuli when they acted as non-targets in an oddball paradigm. With respect to the neutral condition, non-target responses showed an increase in N100 amplitude which was found to depend on two different, but partially overlapping effects. The "early effect" had similar latency and topography as exogenous N100 and may reflect changes in the overall state of alertness since its amplitude declined at the end of the test. The "late effect" affected the N100s descending slope and had features consistent with those of a processing negativity. It was frontally distributed, and topographic mapping revealed a right-sided predominance. Finally, non-target responses exhibited a central positivity (P250) which did not appear in neutral AEPs. P250 shares several features, including latency, amplitude and scalp topography, with the endogenous ERP component commonly labelled "P3a". Non-target P250 could be the result of an attentional shift towards the stimuli, and reflect some aspects of the classification process. We suggest that non-target responses in simple oddball paradigms should be routinely studied along with target responses in order to improve the diagnostic capabilities of cognitive ERPs. Notably, non-target responses may help to decide whether an abnormal target-P300 is related or not to a deficit in the mobilization of attentional resources.     

Coronary sinus thrombosis in patients after heart transplantation

Two cases of coronary sinus thrombosis with myocardial changes suggestive of "haemorrhagic infarsation" as the cause of death of cardiac transplantant recipients are presented. The discussion points to the macroscopical and histologic findings completely different from those seen in myocardial infarction induced by coronary artery occlusion.     

Retention and biomechanics of "retention complexes" 2. Retention complexes of Akers, Roach and Ney

The authors describe the different "retentive complexes" proposed by the Akers, Roach and Ney schools and analyse their biomechanical validity.     

Stomatitis from dentures: etiopathological and therapeutic considerations

Infection of the oral mucous membrane is frequent in patients with removable prostheses, either totally of partially, and particularly when the prostheses is palatal. The principal etiological factor causing the infection is accepted to be "Candidas" aided by the presence of plaque bacteria (in patients with poor oral hygiene care), and a poor fit of the prostheses to the soft tissues. Treatment of the infection must proceed in the following order: a) use of effective medication against oral fungus such as Nystatin or Ketoconazole. b) Meticulous oral hygiene care in the mucous membrane as well as in the prostheses, but using the prostheses as little as possible during the treatment period. c) A total cure of the infection (denture stomatitis) before proceeding to the next phase of the treatment. d) Determination of the adjustment and occlusion of the prostheses in order to determine those areas of the prostheses which need to be refilled because of maladjustment of the prostheses to the soft tissues of the patient.     

Alcoholic foamy degeneration in Spain. Prevalence and clinico-pathological features

Among 389 consecutive chronic alcoholics in whom a liver biopsy was performed for diagnostic purposes, nine patients (2.3%) had histological changes of "alcoholic foamy degeneration" (AFD), characterized by numerous small fat droplets in the swollen hepatocytes of the centrilobular area. In five cases, there were non-specific clinical features, while the other four cases presented acute hepatic decompensation with jaundice and a reduced prothrombin activity. Seven patients had high serum lipid concentrations including hypertriglyceridemia and hypercholesterolemia, which improved after withdrawal of alcohol intake. In conclusion, AFD has a broad clinicopathological spectrum including asymptomatic patients and other cases with severe liver decompensation manifested by jaundice and reduced prothrombin activity. AFD is usually associated with hyperlipemia.     

Factors associated with the blood levels of lead in residents of Mexico City

A study aimed at detecting risk factors for high blood lead levels in Mexico City inhabitants, undertaken at the local National Institute of Public Health, is described. Measurements of blood lead levels for a sample of 300 civil servants were related to several potential risk factors. The statistical analysis was based on analysis of variance and logistic regression. The results of the analysis seem to suggest differences in blood levels by sex, zone of residence, hours of transportation and eating habits, such as the consumption of canned meals and the use of "earthenware dishes" in the preparation of meals. The nature of the study is exploratory, but it seems to suggest directions of research in the complex problem of lead levels in people of polluted cities.     

The effect of the development of the group on the therapeutic effect

The authors compared the results of six-week treatment in a therapeutic community comprising 484 patients who had therapy in groups which were classified as "good" by their therapists, and 91 patients having therapy in groups, classified by the therapists as "poor". No significant difference was found in the two groups as regards mitigation of symptoms, insight, change of attitudes and behavior at the time of completion of treatment and after an interval of one year. Effective factors of group psychotherapy obviously are equally effective also in groups with which the therapists are not satisfied.     

High levels of plasma FVIII and vWF in the toxic epidemic syndrome patients

Factor VIII and von Willebrand factor proteins were evaluated in 115 patients having the chronic phase of the Toxic Epidemic Syndrome (TES), a new multisystemic disease probably caused by the ingestion of denatured rapeseed oil, and in 50 control volunteers. Higher circulating levels of factor VIII procoagulant activity (VIII:C) (158 +/- 58.4 U/dl), von Willebrand factor antigen (vWF:Ag) (166.1 +/- 55.5 U/dl) and von Willebrand factor ristocetin cofactor activity (vWF:RCo) (178.7 +/- 55.2 U/dl) were seen in TES patients (p less than 0.001, TES patients versus control subjects, for each parameter). The increased levels of vWF:Ag and vWF:RCo observed in TES patients correlated with the scleroderma like lesion of the skin, with the sicca syndrome and with Raynaud's phenomenon (p less than 0.01), but not with other clinical manifestations. The multimeric analysis of vWF in 92% of the TES patients was similar to that found in normal plasma, but in the remaining 8% a very slight increase of larger vWF multimers in plasma were observed. The raised levels of vWF found in TES patients in the chronic phase may reflect an "in vivo" vascular injury.     

GABA and its neural regulation in rat brown adipose tissue

Summary By using a radioreceptor assay GABA was detectable in rat interscapular brown adipose tissue (IBAT), the levels being 1% those of CNS and 10-fold those of peripheral plasma. Injection of the glutamic acid decarboxylase (GAD) inhibitor 3-mercaptopropionic acid lowered IBAT GABA levels by about half while injection of the GABA transaminase inhibitor -acetylenic GABA increased them by 230%. Rats kept at 4C for 14 days exhibited IBAT GABA levels that were about half those found at 22C. Accumulation of IBAT GABA after -acetylenic GABA increased by 2-fold in cold-exposed rats. Sympathetic denervation of IBAT prevented the effect of the cold environment on GABA content and impaired that on GABA accumulation. GAD activity was detectable in IBAT homogenates and isolated brown adipocytes. Exposure of rats to cold increased V_max of GAD without modifying its Km, regardless of intactness of innervation. In binding studies with³H-GABA as a ligand, two types of sites were uncovered of K_D=14 and 146 nM, respectively. In the presence of 2.5 mM Ca²⁺ bicuculline and baclofen were 57 and 46% as effective as GABA to displace³H-GABA from IBAT binding sites. The results indicate existence, possible synthesis and type A and B receptors of GABA in rat IBAT.     

Possibilities of finger substitution

Authors deal, in connection with their clinical cases, with the replacement of the fingers of the hand. Attention is called to the fact, that a minimal requirement of the reconstruction, performed on the severe, multiply amputated hand, should be the formation of a "basic hand", and that at the planning of such operations the aim may be the reconstruction of the function of the hand only. Among the methods presented the most modern methods, requiring microvascular surgical technique, are also shown. Although the right of using these is obvious, the older, however well proved methods should not be forgotten either. The possibilities of finger replantation are described didactically; considering the extent of this theme however authors did not strive to completeness.