Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0085383 (hypocapnia)
 1,697 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of long-term cigarette smoking on regional cerebral blood flow (rCBF) were studied in 67 normal male volunteers. All subjects were healthy volunteers without any past history of cerebral and pulmonary disease. rCBF decreased significantly with advancing age. Although there was no significant difference in rCBF between young smokers and nonsmokers, elderly smokers showed significantly lower rCBF than elderly nonsmokers. There was no difference in vital capacity and FEV 1.0% between smokers and nonsmokers in both young and elderly groups. The smokers, however, showed significantly lower V50 than the nonsmokers. PeCO2 in smokers was significantly lower than in nonsmokers. No significant differences were seen in hematocrit, antithrombin III, aggregating platelet, serum lipids and blood pressure between smokers and nonsmokers in both age groups. There was a significantly positive correlation between rCBF and PeCO2 in all groups. These results suggest that long-term smoking may reduce rCBF by means of hypocapnia, resulting from latent small airway disturbances, not by advancing cerebral arteriosclerosis.
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PMID:Effect of smoking on regional cerebral blood flow in the normal aged volunteers. 318 70

Vascular responses to changes in Paco2 are used widely to estimate cerebral perfusion reserve, and they can also be used to assess the degree of arteriosclerosis. In the present study, the effect of aging on cerebral vascular responses to both hypercapnia and hypocapnia was investigated. Cerebral blood flow was measured with positron emission tomography at rest, during hypercapnia, and during hypocapnia in 11 young men and 12 older men. The vascular response to change in Paco2 was calculated as the percent change in cerebral blood flow per absolute change in Paco2 in response to hypercapnia and hypocapnia. The total vascular response to change in Paco2 from hypocapnia to hypercapnia was also calculated. To evaluate age-related changes in regional cerebral vascular responses on a pixel-by-pixel basis, an anatomic standardization technique was also used. Although no significant differences between young and old subjects was observed for vascular responses to both hypercapnia and hypocapnia, a significant decrease in total vascular response was observed with aging, indicating progression of sclerotic changes in the cerebral perforating and medullary arteries with normal aging. According to anatomic standardization analysis, relative capacities for vasodilatation in the cerebellum and insular cortex, and relative capacity for vasoconstriction in the frontal cortex were greater in the younger subjects. Such aging effects should be considered when estimating cerebral perfusion reserve.
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PMID:Effect of aging on cerebral vascular response to Paco2 changes in humans as measured by positron emission tomography. 1217 85