Short- and middle-latency auditory evoked potentials (BAEPs and MAEPs) were studied in 15 chronic alcoholic patients after 1 month's abstinence and compared with those of 15 healthy controls, matching the patients pairwise for sex and age. Most of the parameters studied varied more within the alcoholic group than within the control group. The BAEP results agree with previous reports; in the alcoholic group, BAEP peak V was significantly delayed and the inter-peak intervals, III-V and I-V, were lengthened. The latencies of the MAEP components Na and Pa, on the other hand, were significantly shortened. These findings suggest that chronic abusive consumption of alcohol may bring about structural and/or neurochemical alterations at various levels in the auditory pathway.

Acoustic Stimulation↗

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[Collective medical care institutions in Uruguay. Impact of the regulation].

Collective medical care institutions have been in existence for more than a century and have provided medical care to more than half of Uruguayans through a modality that integrates insurance and provision of services. In the last decade, these institutions have presented a persistent deficit: 52% of the beneficiaries are members of institutions with a deficit of more than 4%. We analyze the impact of the regulation of certain aspects related to the behavior of supply (market concentration and quotas, risk selection, price fixing) and demand (adverse selection and the effect of the co-payments in services utilization). The regulation seems not to have promoted the necessary incentives to efficiency and quality by the IAMC, one of the key aspects to be approached in the context of sectorial reform.

Facility Regulation and Control↗

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Ashy dermatosis in an HIV antibody-positive patient.

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Adult↗

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Acute and chronic effects of alcohol on preattentive auditory processing as reflected by mismatch negativity.

Chronic alcoholism, a major worldwide health problem, is associated with a variety of neurocognitive changes in the afflicted individuals. The precise neurophysiological basis of these changes is not yet understood. Mismatch negativity (MMN) is a preattentive event-related potential component indexing cortical auditory memory traces and automatic change detection in the brain that can be used to study the neural basis of cognitive impairments in various neurodegenerative diseases. MMN studies have revealed that even a low dose of acute alcohol significantly impairs automatic change detection and involuntary attention shifting. Recent MMN results on chronic alcoholism in turn suggest that auditory sensory traces decay slightly faster and are substantially more vulnerable to the distracting effect of backward masking in alcoholics than in healthy subjects. Furthermore, chronic alcohol abuse might accelerate the age-related impairment of automatic change detection. There is also evidence that the MMN changes might predict impaired performance in behavioral memory and attention tasks in alcoholics. In MMN studies of detoxified alcoholics, however, many confounding factors have to be taken into account. For instance, postwithdrawal brain hyperexcitability might be associated with a slightly enhanced or accelerated MMN/MMNm (the magnetic equivalent of MMN). In sum, MMN and MMNm provide an objective noninvasive tool for exploring the neurophysiological functional deficits related to both acute alcohol intoxication and chronic alcoholism.

Acute Disease↗

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Importance of overall treatment time for the response to radiotherapy in patients with squamous cell carcinoma of the head and neck.

In the nineties, several national protocols by the Danish Head and Neck Cancer Study group DAHANCA and other randomized trials, which have included several thousand patients, were performed on squamous cell carcinoma of the head and neck, now the most common malignant disease worldwide. It is a locoregional disease and distant metastases are rarely seen at diagnosis. Radiotherapy and surgery are thus the treatment of choice, with radiotherapy being the treatment modality if organ conservation is required. Since the late eighties there has been a strong focus on the importance of overall treatment time for the outcome of curative radiotherapy for these carcinomas. Based on the results of the Danish protocols it was concluded that the schedule of radiotherapy should be given with the shortest possible overall treatment time. In fact, as a consequence of the loco-regional control rate, the disease-specific and overall survival have shown a significant dependency on the overall treatment time: when this is short, the most beneficial results are achieved. Furthermore, treatment with 6 fractions per week is now the standard radiotherapy in Denmark in most head and neck carcinomas, associated with hypoxic modification using nimorazole. The response to accelerated fractionation is however heterogeneous and until proper predictive factors can be identified and further clarified which are the patients who truly benefit from accelerated fractionation, the radiotherapy schedules should secure a sufficient dose to all patients.

Carcinoma, Squamous Cell↗

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[The secondary effects of the antihistamine chlorpheniramine on the central nervous system].

OBJECTIVE: The objective of this study is to review the main investigations into the secondary effects of the antihistamine chlorpheniramine on the central nervous system (CNS). DEVELOPMENT: The antagonists of the H1 receptors of histamine, usually used in the treatment of symptoms of allergy or the common cold, have many adverse effects on the CNS. They cause day time drowsiness, cause poorer performance of tasks involving visuo motor coordination and make it more difficult to detect target auditory stimuli in tasks involving sustained concentration. When using evoked potentials (EP) it has been observed that they alter the system for maintaining auditory attention. They cause increased P300 latency, an EP related to the voluntary ability to discriminate between relevant stimuli, a reduction in the amplitude of mismatch negativity (MMN), an EP which is seen as a pre attention mechanism for automatic detection of environmental acoustic changes and alters selective attention capacity, reflected by a reduction in the amplitude of processing negativity (PN). CONCLUSIONS: These studies show that chlorpheniramine has major adverse effects on the CNS, and the patient may not be subjectively aware of this (e.g. selective attention). This means that in certain situations it is a dangerous substance. The characteristics of these adverse effects should lead to a review of the prescription of chlorpheniramine, and stimulate the search for other substances with similar therapeutic actions but fewer side effects on the CNS.

Attention↗

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[The potential P300 in the evaluation of the side effects of dexchlorpheniramine].

INTRODUCTION: The antihistamine chlorpheniramine presents multiple adverse side effects on the central nervous system. In earlier work it has been observed that a dose equal to the one used in this study alters the evoked potentials PN (processing negativity) and MMN (mismatch negativity), which are, respectively, indicators of selective attention and of an automatic mechanism for detecting changes in auditory stimulation. AIMS. The aim of the present study was to evaluate the effects of a single 4 mg dose of dexchlorpheniramine on the evoked potential P300, to enable us to better define its effects on the central nervous system. Subjects and methods. Using the double blind procedure, half a sample consisting in 20 subjects was administered 4 mg of dexchlorpheniramine and the other 10 received placebo. 150 minutes after ingestion the potential P300 was recorded using an active oddball paradigm. Likewise, efficiency in detecting target stimuli was also evaluated. RESULTS: results show that a single 4 mg dose of dexchlorpheniramine does not alter P300 nor efficiency in detecting target stimuli. CONCLUSIONS: Results show that the dose used has no effect on voluntary processes involving the categorization of target stimuli nor on their detection. However, the alteration of other attentional mechanisms observed in previous work using the same doses suggests that it would be advisable to employ different evoked potential paradigms in the evaluation of the side effects other active principles or psychoactive substances have on auditory attention.

Adult↗