Semantic memory impairment in Alzheimer's disease: failure of access or degraded knowledge?

A battery of neuropsychological tests designed to assess semantic knowledge about the same items both within and across different modalities was administered to a group of 22 patients with dementia of the Alzheimer type (DAT) and 26 matched controls. The DAT patients were impaired on tests of category fluency, picture naming, spoken word-picture matching, picture sorting and generation of verbal definitions. A relative preservation of superordinate knowledge on the sorting and definition tests, as well as a disproportionate reduction in the generation of exemplars from lower order categories was noted. Analysis of the errors made by each patient across the different tests, revealed a significant correspondence between the individual items. These findings offer compelling evidence that the semantic breakdown in DAT is caused by storage degradation.     

Cognitive profiles of individual patients with Parkinson's disease and dementia: comparison with dementia with lewy bodies and Alzheimer's disease.

We describe the pattern of cognitive profiles within a community-based sample of patients with Parkinson's disease (PD) and dementia (PDD) using cluster analyses, and compare the results with data from patients with Alzheimer's disease (AD) and dementia with Lewy bodies (DLB). Fifty patients with PDD and 39 with AD from Stavanger, Norway, and 62 patients with DLB from San Diego, CA, USA were diagnosed by either standardized clinical procedures or criteria (all PDD and all AD cases) or necropsy (all DLB cases). Four subgroups were identified: two subgroups with a subcortical cognitive profile (one with mild and one with moderate dementia severity), one subgroup with global impairment and severe dementia, and one subgroup with a cortical cognitive profile and moderate dementia. Of the patients with PDD and with DLB, 56% and 55%, respectively, had a subcortical cognitive profile, compared with only 33% of the AD patients. Conversely, 30% of the patients with PDD and 26% of those with DLB had a cortical cognitive profile, compared with 67% of the patients with AD. These findings suggest that in some patients with PDD, frontosubcortical changes are the main contributing factor to dementia, whereas in other patients, cortical and hippocampal changes are more important.     

The psychological and social characteristics of patients referred for NHS cosmetic surgery: quantifying clinical need.

PURPOSE: Elective cosmetic surgery is expanding in the UK in both the public and private sectors. Because resources are constrained, many cosmetic procedures are being excluded within the National Health Service. If guidelines on who can receive such surgery are to be evidence-based, information is needed about the level of dysfunction in patients referred for elective surgery and whether this is related to their degree of physical abnormality. METHOD: Consecutive patients referred to a regional plastic surgery and burns unit for assessment for elective cosmetic surgery completed standardised measures of physical and psychosocial dysfunction, and indicated their perception of the degree of their abnormality and their preoccupation with it. We distinguished between patients referred for physical reasons or appearance reasons only, and compared levels of physical and psychosocial dysfunction in each with published values for community and clinical samples. Surgeons indicated patients' degree of objective abnormality, and we identified the relationship of dysfunction with perceived and objective abnormality and preoccupation. RESULTS: Whether patients sought surgery for physical or appearance reasons, physical function was normal. Those seeking surgery for appearance reasons only had moderate psychosocial dysfunction, but were not as impaired as clinical groups with psychological problems. Patients seeking the correction of minor skin lesions for purely appearance reasons reported excellent physical and psychosocial function. Level of function was related (negatively) to patients' preoccupation with abnormality rather than to their perceived or objective abnormality. CONCLUSIONS: In general, patients referred for elective cosmetic surgery did not present with significant levels of dysfunction. Moreover, levels of functioning were related to preoccupation rather than to objective abnormality. Therefore, for most patients, whether surgical treatment is generally appropriate is questionable. Future guidelines must seek to identify the small minority who do have a clinical need for surgery.     

High Carboxyhemoglobin Concentrations Occur in Swine during Desflurane Anesthesia in the Presence of Partially Dried Carbon Dioxide Absorbents

Background: Increased carboxyhemoglobin concentrations in patients receiving inhalation anesthetics (desflurane, enflurane, and isoflurane) have been reported. Recent in vitro studies suggest that dry carbon dioxide absorbents may allow the production of carbon monoxide.

Methods: The authors used high fresh oxygen flow (5 or 10 l/min) through a conventional circle breathing system of an anesthesia machine for 24 or 48 h to produce absorbent drying. Initial studies used 10 l/min oxygen flow with the reservoir bag removed or with the reservoir bag left in place during absorbent drying (this increases resistance to gas flow through the canister). A third investigation evaluated a lower flow rate (5 l/min) for absorbent drying. Water content of the absorbent and temperature were measured. Pigs received a 1.0 (human) minimum alveolar concentration desflurane anesthetic (7.5%) for 240 min using a 1 l/min oxygen flow rate with dried absorbent. Carbon monoxide concentrations in the circuit and carboxyhemoglobin concentrations in the pigs were measured.

Results: Pigs anesthetized with desflurane using Baralyme exposed to 48 h of 10 l/min oxygen flow (reservoir bag removed) had extremely high carboxyhemoglobin concentrations (more than 80%). Circuit carbon monoxide concentrations during desflurane anesthesia using absorbents exposed to 10 l/min oxygen flow (reservoir bag, 24 h) reached peak values of 8,800 to 13,600 ppm, depending on the absorbent used. Carboxyhemoglobin concentrations reached peak values of 73% (Baralyme) and 53% (soda lime). The water content of Baralyme decreased from 12.1 +/- 0.3% (mean +/- SEM) to as low as 1.9 +/- 0.4% at the bottom of the lower canister (oxygen flow direction during drying was from bottom to top). Absorbent temperatures in the bottom canister increased to temperatures as high as 50 [degree sign] Celsius. With the reservoir bag in place during drying (10 l/min oxygen flow), water removal from Baralyme was insufficient to produce carbon monoxide (lowest water content = 5.5%). Use of 5 l/min oxygen flow (reservoir bag removed) for 24 h did not reduce water content sufficiently to produce carbon dioxide with desflurane.