Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

[Q]: Context: Microvascular alterations contribute to the development of stroke and vascular dementia. The goal of this study was to evaluate age and hypertension related changes of the basal lamina in cerebral microvessels of individuals, who died from non-cerebral causes.', 'We examined 27 human brains: 11 young and 16 old patients. Old patients were divided into two subgroups, those with hypertension (n = 8) and those without hypertension (n = 8). Basal lamina changes of the cerebral microvessels were determined in the putamen using antibodies against collagen type IV and by quantitative analysis of vessel number, total stained area of collagen, thickness of the vessel wall and lumen, and relative staining intensity using immunofluorescence. The total number of collagen positive vessels per microscopic field was reduced in old compared to young subjects (12.0+/-0.6 vs. 15.1+/-1.2, p = 0.02). The relative collagen content per vessel (1.01+/-0.06 vs. 0.76+/-0.05, p = 0.01) and the relative collagen intensity (233.1+/-4.5 vs. 167.8+/-10.6, p < 0.0001) shown by immunofluorescence were higher in the older compared to the younger patients with a consecutive reduction of the lumen / wall ratio (1.29+/-0.05 vs. 3.29+/-0.15, p < 0.0001). No differences were observed for these parameters between old hypertensive and non-hypertensive patients.
Answer: The present data show age-related changes of the cerebral microvessels in sections of human putamen for the first time. Due to the accumulation of collagen, microvessels thicken and show a reduction in their lumen. Besides this, the number of vessels decreases. These findings might represent a precondition for the development of vascular cognitive impairment. However, hypertension was not proven to modulate these changes.
[A]: Is aging associated with increased collagen type IV accumulation in the basal lamina of human cerebral microvessels?


[Q]: Context: Parkinsonian signs, especially gait impairment, are common and associated with morbidity and mortality in older persons. Our objective was to test the hypothesis that substantia nigra neurofibrillary tangles (NFTs) are related to parkinsonian signs in older persons with and without dementia.', "We studied 86 deceased older Catholic clergy without idiopathic Parkinson's disease from the Religious Order Study, a longitudinal clinical-pathological study. Mean age at death was 85.3 years. Signs of gait disturbance, bradykinesia, rigidity, and tremor were assessed proximate to death using a modified Unified Parkinson's Disease Rating Scale. Forty-micrometer paraffin-embedded sections of substantia nigra were bleached before tau immunohistochemistry and the optical disector was used to count NFTs. We used multivariable linear regression to examine parkinsonian signs as a function of nigra NFTs, controlling for age, sex, education, and cortical NFTs.", 'Substantia nigra NFTs were present in 67 of 86 persons (77.9%). After controlling for age, sex, education, and cortical NFTs, nigra NFTs were related to gait impairment (p < 0.001), but not bradykinesia, rigidity, or tremor. Results were not confounded by dementia, Braak score, neuroleptic medication, cerebral infarcts, or Lewy bodies.
Answer: NFTs in the substantia nigra are associated with gait impairment in older persons with and without dementia.
[A]: Are substantia nigra tangles related to gait impairment in older persons?


[Q]: Context: The objective of this study was to describe a pattern of recovery and histological nerve cell loss in Sprague-Dawley rats exposed to severe brain ischemia and to compare it to that of Wistar rats.', 'Ether- and ketamine-anesthetized Sprague-Dawley rats were exposed to 3, 5, 6 and 10 min of normothermic severe brain ischemia (4 groups) induced by hypotension and neck compression. In group No. 5, the brain temperature was rapidly lowered, after 10 min of ischemia, to 30 degrees C during 45-50 min of recirculation. Wistar rats (group No. 6) served as controls (10-min normothermic ischemia).', 'In Sprague-Dawley (S-D) rats, post-ischemic audiogenic seizures (PAS) increased with the duration of ischemia and reached 86% (6/7 rats), after 10 min of ischemia. Mortality rate was high (50% = 7/14 rats). No seizure activity was observed after 10 min of ischemia in 6 Wistar (W) rats, and all survived. In the S-D rats, 10 min of ischemia produced histopathological damage in all brain regions examined, except in the thalamus. Damage was less severe in the W rats. Post-ischemic hypothermia ameliorated hippocampal and cortical nerve cell damage, but had no effect on the incidence of PAS activity and mortality. In W rats, hippocampal nerve cell loss was much less severe than in the S-D rats and cortical damage was not observed.
Answer: Sprague-Dawley rats develop post-ischemic audiogenic seizures more frequently than Wistar rats and mortality rate is high. The incidence of post-ischemic audiogenic seizures and mortality correlates well with the duration of ischemia. Post-ischemic moderate hypothermia (30 degrees C) significantly ameliorated the hippocampal and cortical nerve cell losses after 10 min of severe brain ischemia, but did not improve outcome. It appears that the high mortality rate of S-D rats following brain ischemia is related to frequent post-ischemic audiogenic seizures.
[A]:
Does post-ischemic hypothermia ameliorate ischemic brain damage but not post-ischemic audiogenic seizures in rats?