Factors associated with resistance to dementia despite high Alzheimer disease pathology

BACKGROUND

Autopsy series have shown that some elderly people remain with normal cognitive function during life despite having high burdens of pathologic lesions associated with Alzheimer disease (AD) at death. Understanding why these individuals show no cognitive decline, despite high AD pathologic burdens, may be key to discovery of neuroprotective mechanisms.

METHODS

A total of 36 subjects who on autopsy had Braak stage V or VI and moderate or frequent neuritic plaque scores based on Consortium to Establish a Registry for Alzheimer's Disease (CERAD) standards were included. Twelve had normal cognitive function and 24 a diagnosis of AD before death. Demographic characteristics, clinical and pathologic data, as well as antemortem brain volumes were compared between the groups.

RESULTS

In multiple regression analysis, antemortem hippocampal and total brain volumes were significantly larger in the group with normal cognitive function after adjusting for gender, age at MRI, time from MRI to death, Braak stage, CERAD neuritic plaque score, and overall presence of vascular disease.

CONCLUSION

Larger brain and hippocampal volumes were associated with preserved cognitive function during life despite a high burden of Alzheimer disease (AD) pathologic lesions at death. A better understanding of processes that lead to preservation of brain volume may provide important clues for the discovery of mechanisms that protect the elderly from AD.

Public opinion and knowledge about childhood sexual abuse in a rural community

OBJECTIVES

To explore the knowledge and attitudes of the general public about child sexual abuse (CSA) through a population-based survey.

METHOD

A survey was completed by 246 respondents living in Klamath Falls, a small city in rural eastern Oregon. Specific areas of inquiry included who respondents believed were likely perpetrators of CSA, when a child was most likely to disclose sexual abuse, whether respondents believed that children would be truthful, reasons a child might not acknowledge that they had been sexually abused, what respondents knew about how CSA could be diagnosed, and what attitudes respondents thought that a sexually abused child might have towards the perpetrators of their abuse. Finally, respondents were asked how they would report a suspected case of CSA and about their receptivity to personal safety training to prevent CSA.

RESULTS

While significant proportions of respondents were fairly knowledgeable about CSA, gaps in knowledge were found in all age groups and ethnic groups. Groups with the most significant knowledge deficits about CSA included men, unmarried respondents, respondents who had not had children, respondents in younger age groups, respondents of Latino descent, and respondents with low incomes or low education. Respondents were most likely to report CSA to their physician or the police. There is community interest in training about CSA and its prevention.

CONCLUSION

These data indicate that significant deficits as well as strengths in knowledge about CSA exist in this rural community, and identify populations to which community education about CSA could be directed.

Redox-dependent conformational changes are common structural features of cytochrome c from various species

Discrepant results from X-ray crystallographic and physicochemical studies on the conformations of the two redox states of cytochrome c raise important questions about the nature of redox-dependent conformational changes and whether differences are common structural features of various cytochrome c species. Comparative studies of cytochrome c from 10 species (horse, cow, sheep, pig, dog, rabbit, chicken, pigeon, tuna, and baker's yeast) in aqueous solutions were carried out using Fourier transform infrared (FT-IR) spectroscopy. The second-derivative analysis revealed similar conformational changes in all 10 species upon reduction of the heme iron regardless of the differences in the amino acid sequences. The redox-dependent changes involve the amide I regions ascribed to extended beta-structure, beta-turn, and alpha-helix structures. Three species (cow, sheep, and pig) with identical amino acid sequences displayed nearly identical infrared spectra for the oxidized and reduced states, which rules out the possible contribution of experimental error. These results show unequivocally that redox-dependent conformational changes are common structural feature of various cytochrome c species and demonstrate the usefulness of FT-IR spectroscopy as a quick and inexpensive tool in comparative studies of functionally related conformational changes of proteins.

Potential neurologic toxicity related to ciprofloxacin

A 74-year-old woman with multiple medical problems including chronic renal failure was admitted for treatment of a diabetic foot infection. On day 12 of therapy with oral ciprofloxacin and metronidazole, the patient experienced generalized myoclonus and muscle twitching. At that time it was realized that although the ciprofloxacin regimen prescribed was a usual dose for a skin and soft-tissue infection, it was excessive for her degree of renal function. This was thought to be the most likely cause of the patient's neurotoxicity. Seizure activity has been reported to occur with the quinolone antibiotics and, with the increasing use of these agents, dose reductions should be kept in mind to avoid potentially serious adverse reactions.