Midlife blood pressure and dementia: the Honolulu-Asia aging study

We studied the association of mid-life blood pressure to late age dementia, specifically Alzheimer's disease and vascular dementia. Data are from the cohort of 3703 Japanese-American men who were followed in the Honolulu Heart Program (HHP;1965-1971), and subsequently re-examined in 1991 for dementia. We assessed the risk (odds ratio (95% CI)) for dementia associated with categories of systolic (SBP) and diastolic blood pressure (DBP), stratified by never/ever treatment with anti-hypertensive medications, and adjusting for age, education, apolipoprotein epsilon allele, smoking and alcohol intake. Among those never treated (57% sample), the risk for dementia was OR 95% CI 3.8 (1.6-8.7) for DBP of 90-94 mm Hg, and 4. 3 (1.7-10.8) for DBP of 95 mmHg and over compared to those with DBP of 80 to 89 mm Hg. Compared to those with SBP of 110 to 139 mm Hg, the risk for dementia was 4.8 (2.0-11.0) in those with SBP 160 mm Hg and higher. Blood pressure was not associated with the risk for dementia in treated men. These results were consistent for Alzheimer's disease and vascular dementia. This study suggests elevated levels of blood pressure in middle age can increase the risk for late age dementia in men never treated with anti-hypertensive medication.

Microscopic Drop Profiles and the Origins of Line Tension

The line tension associated with the three-phase contact line of a liquid drop on a rigid substrate is calculated as the excess free energy per unit length of the contact line relative to the free energy of the drop/substrate system when the interaction between the free liquid interface and the substrate is turned off. To perform this calculation, the interaction energy is treated in the Derjaguin approximation and the microscopic drop profile determined accordingly. An explicit expression for the line tension as a function of the macroscopic contact angle for the case of an infinite drop is obtained as a quadrature over the interaction energy per unit area between planar half-spaces. The magnitude of the line tension is shown to be the product of the free liquid surface tension and the length scale associated with the interaction energy. For attractive interaction energies the line tension is negative but when the interaction has both an attractive component (which must dominate at small separations) and a repulsive component which dominates at larger separations, the line tension can be positive. Some simple physical models of the interaction are considered to illustrate these points. For the case of a finite drop, we show that the concept of line tension as a macroscopic quantity which may be added to the free energy balance, giving rise to deviation from Young's equation for the contact angle, is a valid one in the sense that a full treatment of the microscopic drop shape yields the same macroscopic picture of the drop near contact. The line tension for a finite drop is demonstrated to be the value calculated for the infinite drop to within terms of the order of the ratio of interaction energy range to drop radius. Hence, the treatment of line tension as a macroscopic concept is valid down to drop sizes of the order of the range of the interaction energy. Finally, by applying the Derjaguin approximation in a different (but equally valid) way and deriving an alternate expression for the line tension, we are able to elucidate the range of validity of the approximation itself. Line tensions calculated by these methods would appear to be accurate for contact angles up to approximately 20 degrees. Copyright 1999 Academic Press.

Cytokines increase endothelin ETB receptor contractile activity in rat cerebral artery

The plasticity of endothelin ETB receptor activity and the influence of pro-inflammatory cytokines was examined in cerebral artery. In fresh rat basilar artery, the selective ETB receptor agonist, sarafotoxin S6c, induced negligible contractions. However, after 1 day of organ culture, fully defined concentration-response curves were obtained in artery segments exposed to sarafotoxin S6c. Organ culture in the presence of either interleukin-1 beta or tumour necrosis factor-alpha, but not interleukin-2 or interleukin-6, further amplified the maximal contraction to sarafotoxin S6c. The plasticity of ETB receptor expression in cerebral arteries and sensitivity for pro-inflammatory cytokines, suggest a role in inflammatory cerebral diseases such as stroke.

Characterization of risk factors for vascular dementia: the Honolulu-Asia Aging Study

BACKGROUND

The Honolulu Heart Program (HHP) is a prospective study of heart disease and stroke that has accumulated risk factor data on a cohort of 8,006 Japanese American men since the study began in 1965. A recent examination of the cohort identified all patients with vascular dementia (VaD) using the criteria of the California Alzheimer's Disease Diagnostic and Treatment Center.

OBJECTIVE

To characterize patients with VaD by stroke subtype and to investigate risk factors for VaD in a cohort of Japanese American men, aged 71 to 93, living in Hawaii and participating in the HHP.

METHODS

Sixty-eight men with VaD were compared with 3,335 men without dementia or stroke (NSND). Men with VaD were also compared with 106 men with stroke who were not demented (SND). Candidate risk factors were measured prospectively.

RESULTS

Of the 68 men with VaD there were 34 (50%) whose VaD was attributed to small vessel infarcts, 16 (23%) whose VaD was related to large vessel infarcts, and 11 (16%) with both large and small vessel infarcts. The remainder could not be classified. In a multivariate logistic regression model for VaD compared with NSND containing variables found to be associated with VaD in a univariate analysis, age (odds ratio [OR] 1.19, 95% confidence interval [CI] 1.13 to 1.27), coronary heart disease (OR 2.50, 95% CI 1.35 to 4.62), and 1-hour postprandial glucose (OR 1.41, 95% CI 1.06 to 1.88) remained significantly predictive of VaD, whereas preference for a Western diet (OR 0.54, 95% CI 0.30 to 0.98) as opposed to an Oriental or mixed diet and use of supplementary vitamin E (OR 0.32, 95% CI 0.12 to 0.82) were protective. A similar model for the comparison of men with VaD and SND revealed age (OR 1.24, 95% CI 1.14 to 1.35) was predictive of VaD, whereas preference for a Western diet (OR 0.43, 95% CI 0.22 to 0.86) was protective.

CONCLUSIONS

The most common stroke subtype associated with VaD was lacunar stroke. Age and traditional vascular risk factors are important contributors to the development of VaD in late life. The antioxidant vitamin E and presently unknown factors related to a Western diet as opposed to an Oriental diet may be protective against developing VaD.

Effects of walking on coronary heart disease in elderly men: the Honolulu Heart Program

BACKGROUND

Effects of walking on the risk of coronary heart disease morbidity and mortality have not been identified in the elderly. The purpose of this study was to determine whether walking is associated with a reduced risk of coronary heart disease in a sample of elderly men.

METHODS AND RESULTS

For this study, distance walked (mile/d) was examined at a baseline examination that occurred from 1991 to 1993 in the Honolulu Heart Program. Incident coronary heart disease from all causes was observed over a 2- to 4-year follow-up period. Subjects followed up were 2678 physically capable elderly men aged 71 to 93 years. During the course of follow-up, 109 men developed coronary heart disease. Men who walked <0.25 mile/d had a 2-fold increased risk of coronary heart disease versus those who walked >1. 5 mile/d (5.1% versus 2.5%; P<0.01). Men who walked 0.25 to 1.5 mile/d were also at a significantly higher risk of coronary heart disease than men who walked longer distances (4.5% versus 2.5%; P<0. 05). Adjustment for age and other risk factors failed to alter these findings.

CONCLUSIONS

Findings from the Honolulu Heart Program, which targeted physically capable elderly men, suggest that the risk of coronary heart disease is reduced with increases in distance walked. Combined with evidence that suggests that an active lifestyle reduces the risk of cardiovascular disease in younger and more diverse groups, this suggests that important health benefits could be derived by encouraging the elderly to walk.

Proton magnetic resonance spectroscopy of brain biopsies from patients with intractable epilepsy

In the present study metabolite concentrations were determined by proton magnetic resonance spectroscopy (MRS) in biopsies obtained from patients suffering intractable epilepsy from several different causes. Seven patients had gliosis, four had mild cortical dysplasia, three had tuberous sclerosis, two had astrocytomas, and one had a cavernous angioma. No significant differences were found in gliotic tissue in comparison with controls except for an increase in lactate. However, in the subgroup with tuberous sclerosis an increase was found in GABA and a dramatic decrease in N-acetyl aspartate (NAA). The most marked changes were found in the group with mild cortical dysplasia. There was a considerable decrease in NAA as well as large increases in GABA, alanine, tyrosine, acetate, inositol, glucose and lactate. The GABA content did not appear to correlate with antiepileptic therapy. Moreover, since all these patients required surgery, an elevated GABA level does not necessarily provide protection from seizures. The results indicate that use of proton MRS could become a useful presurgical predictor of underlying pathology.

Interleukin-1beta potentiates endothelin ET(B) receptor-mediated contraction in cultured segments of human temporal artery

Segments of human temporal artery were placed in organ culture for up to 4 days and examined for endothelin ET(B) receptor activity in the presence and absence of the pro-inflammatory cytokine interleukin-1beta (IL-1beta) by in vitro pharmacology and reverse transcriptase-polymerase chain reaction (RT-PCR). The contractile effect of prostaglandin F2alpha (used as a reference), was not significantly altered by culture or IL-1beta. However, the selective ET(B) agonist sarafotoxin S6c induced no contraction in fresh arteries, but marked contraction after culture. Both maximal contraction and potency to sarafotoxin S6c were increased in segments incubated with IL-1beta . The contraction was sensitive to BQ 788 (ET(B) antagonist), but not FR 139317 (ET(A) antagonist). Actinomycin D abolished the contraction, whereas only the cytokine-induced increase in contraction was inhibited by cycloheximide. ET(A) and ET(B) receptor mRNAs were detected in all arteries; predominantly for the ET(A) receptor in fresh arteries, and for the ET(B) receptor after culture. However, there was no change in the ET(A)/ET(B) receptor mRNA ratio after treatment with IL-1beta. This suggests de novo synthesis of contractile ET(B) receptors after organ culture and that IL- 1beta may further stimulate translation of the mRNA to active receptors. The results raise the possibility that contractile ET(B) receptors may be implicated in disease states with inflammatory processes.

Associations of symptoms of sleep apnea with cardiovascular disease, cognitive impairment, and mortality among older Japanese-American men

OBJECTIVES

To examine the association between symptoms of sleep apnea and prevalent cardiovascular disease, cognitive impairment, and subsequent 3-year mortality.

DESIGN

A longitudinal study.

SETTING

Participants lived in the community on Oahu, Hawaii.

PARTICIPANTS

A total of 2905 older Japanese-American men participating in the fourth examination of the Honolulu Heart Program cohort study from 1991-1993, which is the baseline for the Honolulu-Asia Aging Study of dementia.

MEASUREMENTS

Self-reported snoring, daytime sleepiness, and breathing pauses; diagnosed cardiovascular disease and dementia; cognitive functioning and vital status approximately 3 years later.

RESULTS

More than 12% of the participants reported that they often or always snored loudly, and 8% reported being sleepy most of the day. Fewer than 2% reported that they stop breathing when sleeping, and this was found more frequently among habitual snorers (7%, P < .001) and those sleepy during the day (5%, P < .001). The prevalence of habitual snoring declined in the older age groups, was higher among those with greater Body Mass Index scores, and was not associated with the reporting of daytime sleepiness, diagnosis of heart disease, stroke, dementia, or cognitive impairment. Daytime sleepiness was more prevalent at older ages and was associated with a higher prevalence of heart disease and with cognitive impairment and dementia, chronic obstructive pulmonary disease, and diabetes. Self-reported apnea was associated only with a history of pneumonia. Three-year mortality was not associated with these symptoms after adjusting for prevalent heart disease and cognitive impairment.

CONCLUSION

Symptoms of sleep apnea are reported less frequently in older Japanese-American men. Excessive daytime sleepiness is associated with poor cognition and dementia, but whether it also is an indicator for sleep apnea in this age group remains unclear. Epidemiologic studies of sleep apnea in older adults will require polysomnography to determine accurately the correlates and consequences of this condition.

Longitudinal association of vascular and Alzheimer's dementias, diabetes, and glucose tolerance

OBJECTIVE

To assess the relationship between impaired glucose tolerance and both vascular dementia and AD.

BACKGROUND

Diabetes and abnormalities of glucose metabolism have been associated with stroke and poor cognitive function. In addition, glycoproteins and glycosylation have been postulated to be associated with the development of neuritic plaques characteristic of AD.

METHODS

A historical prospective cohort study of Japanese-American men (n = 3,774), who were examined at ages 45 to 68 (1965 through 1968) and again at ages 71 to 93 (1991 through 1993). Measurements were obtained by clinical and home examinations: assessment of glucose intolerance (nonfasting 1 hour after glucose load) from 1965 through 1968 and history of diabetes diagnosed by a physician at examinations given from 1965 through 1968 and from 1976 through 1978. At the 1991 through 1993 examinations, the Cognitive Assessment Screening Instrument (CASI)-an instrument designed for use in cross-cultural settings combining features of the Folstein Mini-Mental State Examination, the Modified Mini-Mental State Examination, and the Hasegawa Dementia Screening Scale-was used. Diagnosis and classification of AD and vascular dementia were made by a consensus panel using neuropsychologic assessment data, a neurologist's evaluation, and information from a family informant. Diagnostic and Statistical Manual of Mental Disorders, 3rd ed., revised criteria were used to establish dementia, and subclassification by cause was based on other published criteria.

RESULTS

No association between AD and diabetes, present either 25 or 15 years previously, was found after adjustment for age and education in a multiple regression model. A significant association was found between impaired glucose tolerance at baseline and vascular dementia (p < 0.01).

CONCLUSIONS

These findings confirm expected relationships between impaired glucose tolerance and stroke-related dementia but do not support an association of disordered glucose metabolism with AD.

Predictors of healthy aging in men with high life expectancies

OBJECTIVE

The purpose of this study was to identify risk factors that consistently predict staying healthy in contrast to developing clinical illness and/or physical and mental impairments.

METHODS

More than 8000 men of Japanese ancestry were followed for 28 years with repeat examinations and surveillance for deaths and incident clinical illness. Physical and cognitive functions were measured in 1993. Measures of healthy aging included surviving and remaining free of major chronic illnesses and physical and cognitive impairments.

RESULTS

Of 6505 healthy men at baseline, 2524 (39%) died prior to the final exam. Of the 3263 available survivors, 41% remained free of major clinical illnesses, 40% remained free of both physical and cognitive impairment, and 19% remained free of both illness and impairment. The most consistent predictors of healthy aging were low blood pressure, low serum glucose, not smoking cigarettes, and not being obese.

CONCLUSIONS

Beyond the biological effects of aging, much of the illness and disability in the elderly is related to risk factors present at midlife.

Height as a marker of childhood development and late-life cognitive function: the Honolulu-Asia Aging Study

OBJECTIVE

Growing evidence suggests that structural and functional brain reserves, thought to develop in childhood and adolescence, may be crucial in determining when cognitive impairment begins. The purpose of this report is to examine the relationship of height, as a marker of childhood development, to late-life cognitive function in a sample of elderly Japanese-American men.

METHOD

Cognitive performance was assessed from 1991 to 1993 in the Honolulu-Asia Aging Study in 3733 men aged 71 to 93 years and related to height that was measured 25 years earlier.

RESULTS

Among the study sample, shorter men were older, leaner, and less educated than taller men. Shorter men also spent more years of their childhood living in Japan and were more likely to have had fathers in unskilled professions. After adjustment for age, the prevalence of poor cognitive performance declined consistently with increasing height from 25% in men shorter than 154 cm (61 in) to 9% in those taller than 174 cm (69 in). Excluding men with stroke or dementia did not alter the association between height and cognitive performance. Apolipoprotein E4 was unrelated to height and did not effect the association between height and cognitive function. The prevalence of Alzheimer's disease was higher in men who were 154 cm (61 in) or shorter as compared with men who were taller (4.7% vs 2.9%, respectively). There was no association between height and vascular dementia.

CONCLUSION

Efforts to improve prenatal and early life conditions to maximize growth in childhood and adolescence could diminish or delay the expression of cognitive impairments that occur later in life. Prevention of some late-life cognitive impairments may have pediatric origins.

Increased endothelin ETB contractile activity in cultured segments of human temporal artery

Contractions induced by endothelin-1, endothelin-3 and the selective ETB agonist, sarafotoxin S6c, were studied in segments of human temporal artery. The results in fresh arteries were compared with those obtained after 1 or 4 days in organ culture, and with the specific ETA antagonist FR 139,317, the specific, mixed antagonist bosentan, or the specific ETB antagonist, BQ 788. Sarafotoxin S6c induced no contractile activity in fresh artery segments, but elicited marked contractions after culture. This contraction was only slightly inhibited by FR 139,317, but was abolished by BQ 788. Contractions induced by endothelin-1 were antagonized by FR 139,317 and bosentan, but not by BQ 788. Organ culture did not change the overall pattern, but all concentration-response curves were shifted leftwards. Contractions induced by endothelin-3 were abolished by all antagonists in fresh arteries, but some activity was restored after organ culture. Sensitivity to endothelin-3 was markedly increased. The results suggest a change in endothelin receptors during organ culture, resulting in a marked increase in contractile ETB activity, and possibly some increase in ETA activity. Such changes illustrate the complexity of endothelin responses in this vascular bed.

[U-13C] aspartate metabolism in cultured cortical astrocytes and cerebellar granule neurons studied by NMR spectroscopy

The metabolism of [U-13C]aspartate was studied in cultured cortical astrocytes and cerebellar granule neurons in the presence of glucose and during inhibition of glycolysis. Redissolved, lyophilized cell extracts and incubation media were analyzed by 13C nuclear magnetic resonance spectroscopy for the determination of metabolites labeled from aspartate. Uniformly labeled lactate was prominent in control media of astrocytes and cerebellar granule neurons. In both cell types, aspartate entered the tricarboxylic acid (TCA) cycle, as shown by labeling patterns in glutamate and, in astrocytes, in glutamine. From the complex labeling patterns in aspartate in astrocytic perchloric acid extracts it was clear that acetylcoenzyme A (acetyl-CoA) derived from aspartate via oxaloacetate and pyruvate could enter the TCA cycle. Such "recycling," however, could not be detected in cerebellar granule neurons. Inhibition of glycolysis reduced aspartate uptake and metabolism in both cell types. Most notably, lactate derived from aspartate showed a large reduction, and in astrocytes, incorporation of labeled acetyl-CoA into the TCA cycle was significantly reduced. Thus, astrocytes and cerebellar granule neurons differ in their handling of aspartate. Furthermore, inhibition of glycolysis clearly affected aspartate metabolism by such cells.

Phonophobia in migraine

Quantitative measurement of sound-induced discomfort and pain thresholds showed that migraineurs (n = 65) were significantly more sensitive than headache-free controls (n = 80), both during and outside attack (p < 0.0001). Patients tested with head pain had lower thresholds than those tested without pain (p < 0.01). Migraine with and without aura did not differ as to sound sensitivity. There were no significant differences in thresholds between the symptomatic and nonsymptomatic sides (p > or = 0.78). Patients with unilateral headache or pain of pulsating character were more sensitive than those with bilateral headache or pressing pain (p < 0.05). Phonophobia did not correlate significantly with duration, frequency, or severity of attacks. The main results were in accordance with a questionnaire study concerning subjective evaluation of sound sensitivity. Similarities between phonophobia and photophobia in migraine provide evidence that both phenomena share a common pathophysiological mechanism in this condition.

[U-13C]glutamate metabolism in astrocytes during hypoglycemia and hypoxia

The ability of cultured astrocytes to metabolize [U-13C]glutamate in the absence of glucose was investigated by utilizing 13C nuclear magnetic resonance spectroscopy to identify 13C-labeled metabolites. Control cultures (3 mM glucose), hypoglycemic cultures (glucose-deprived), severe hypoglycemic cultures (glucose-deprived, 0.5 mM iodoacetate as an inhibitor of glycolysis), hypoglycemic/hypoxic cultures, and cultures deprived of all additional substrates were incubated for 2 hr in medium containing 0.5 mM glutamate (50% [U-13C]glutamate). Glucose deprivation alone had little effect on removal of glutamate from the culture medium, but the presence of iodoacetate or incubating cultures in a low-oxygen atmosphere decreased glutamate clearance. Only the withdrawal of all substrates other than glutamate decreased glutamine synthesis. Metabolism of glutamate through the tricarboxylic acid (TCA) cycle was evident by the appearance of [1,2,3-13C]glutamate and [U-13C]aspartate in cell extracts and [U-13C]lactate in cell media. Lactate derived from TCA cycle intermediates was significantly reduced after glucose deprivation and even more so after severe hypoglycemia. Release of glutamate from astrocytes was observed under all incubation conditions. [U-13C]Aspartate was not detected in control media but was released from glucose-deprived cells when oxygen was available. Increased release was observed in the presence of iodoacetate. After withdrawal of all substrates other than glutamate, [U-13C]aspartate was the only metabolite observed intracellularly, whereas aspartate, glutamine, and 5-oxoproline were detected in the incubation medium. The present results indicate that glutamate-to-aspartate conversion is preferentially utilized by astrocytes when oxygen is available but glycolysis is impaired.

Effects of walking on mortality among nonsmoking retired men

BACKGROUND

The potential benefit of low-intensity activity in terms of longevity among older men has not been clearly documented. We examined the association between walking and mortality in a cohort of retired men who were nonsmokers and physically capable of participating in low-intensity activities on a daily basis.

METHODS

We studied 707 nonsmoking retired men, 61 to 81 years of age, who were enrolled in the Honolulu Heart Program. The distance walked (miles per day) was recorded at a base-line examination, which took place between 1980 and 1982. Data on overall mortality (from any cause) were collected over a 12-year period of follow-up.

RESULTS

During the follow-up period, there were 208 deaths. After adjustment for age, the mortality rate among the men who walked less than 1 mile (1.6 km) per day was nearly twice that among those who walked more than 2 miles (3.2 km) per day (40.5 percent vs. 23.8 percent, P=0.001). The cumulative incidence of death after 12 years for the most active walkers was reached in less than 7 years among the men who were least active. The distance walked remained inversely related to mortality after adjustment for overall measures of activity and other risk factors (P=0.01).

CONCLUSIONS

Our findings in older physically capable men indicate that regular walking is associated with a lower overall mortality rate. Encouraging elderly people to walk may benefit their health.

Prevalence and correlates of dementia: survey of the last days of life

OBJECTIVES

To estimate the prevalence and correlates of dementia at death and to assess the usefulness of death certificate data in the reporting of dementia.

METHODS

The authors analyzed next-of-kin interviews for 599 male and 628 female decedents using data from the National Institute on Aging's Survey of the Last Days of Life.

RESULTS

Death certificate data in this population show the prevalence of dementia to be less than 1%, consistent with previous reports based on death certificates but a substantial underestimate compared to the 11.9% reported in a national survey. Using a dementia index based on the informant's report of whether the decedent had been diagnosed with a dementing illness and the extent of her or his cognitive and functional limitations, this study found a prevalence of dementia of 8.5%. A high score on the dementia index was significantly associated with older age, Parkinson's disease, and incontinence. Lower relative odds for dementia at death were found for people with either a lifetime history or a death certificate report of cancer. Similarly, people with a lifetime history of coronary heart disease were found to have lower relative odds for dementia at death.

CONCLUSION

These results suggest that informant interviews may be a useful source of data to examine factors associated with dementia and to estimate the prevalence of dementia in the last year of life.

Lactate formation from [U-13C]aspartate in cultured astrocytes: compartmentation of pyruvate metabolism

Metabolism of [U-13C]aspartate in cultured astrocytes and the effects of inhibitors of malic enzyme and phosphoenolpyruvate carboxykinase (hydroxymalonate and 3-mercaptopicolinic acid, respectively) were studied using 13C nuclear magnetic resonance (NMR) spectroscopy. The labelling of glutamate and glutamine showed entry of aspartate into the tricarboxylic acid (TCA) cycle after conversion to oxaloacetate. Production of [U-13C]pyruvate from [U-13C]aspartate was revealed by the presence of [U-13C]lactate in incubation media. Furthermore, labelling patterns in C-2 and C-3 in intracellular aspartate showed entry of [1,2-13C]acetyl-CoA into the TCA cycle; evidence for pyruvate-recycling. No reduction in [U-13C]lactate was observed in the presence of either enzyme inhibitor. However, 3-mercaptopicolinic acid reduced incorporation of labelled acetyl-CoA into TCA cycle intermediates, indicating compartmentation of pyruvate production in astrocytes.

Light-induced discomfort and pain in migraine

Quantitative thresholds for discomfort and pain with monocular and binocular light stimuli were measured in 67 controls and 67 migraine patients (37 migraine with aura and 30 migraine without aura). Patients were more photophobic during attack than outside attack (p < 0.03), and they were more sensitive to light than controls even between attacks (p < or = 0.0001). We found no differences in light sensitivity between migraine with aura and migraine without aura (p > or = 0.93). Unilateral pain affected light sensitivity on both sides. When asked with a questionnaire, 74% of patients answered that they were sensitive to light outside attack and 100% were sensitive during attack. Pain thresholds were generally lower among sensitive than non-sensitive patients (p = 0.004), indicating some agreement between subjective opinion and objective measurements of photophobia. Photophobia seems to be an intrinsic property of migraineurs. It is increased by migraine pain, but seems to be unrelated to migraine characteristics such as nausea, severity of attacks, pain character and pain laterality.

Computerized analysis of isometric tension studies provides important additional information about vasomotor activity

Concentration-response curves of isometric tension studies on isolated blood vessels are obtained traditionally. Although parameters such as Imax, EC50 and pA2 may be readily calculated, this method does not provide information on the temporal profile of the responses or the actual nature of the reaction curves. Computerized data acquisition systems can be used to obtain average data that represent a new source of otherwise inaccessible information, since early and late responses may be observed separately in detail.

Nuclear magnetic resonance spectroscopy of cerebrospinal fluid from patients with low back pain and sciatica

STUDY DESIGN

This study was carried out to assess the metabolic differences between pain-free control subjects and patients with low back pain, either with or without disc protrusion or herniation.

OBJECTIVES

To analyze various metabolites in human cerebrospinal fluid using proton nuclear magnetic resonance spectroscopy. The potential use of this technique as an additional tool for diagnostic assessment was also evaluated.

SUMMARY OF BACKGROUND DATA

Inflammation is thought to play a major role in the generation of lumbar spine pain, a theory supported both by animal and in vitro studies. The effect of the inflammation in terms of increased metabolism has not yet been studied.

METHODS

Cerebrospinal fluid was obtained from patients by lumbar puncture, frozen, redissolved, and analyzed for metabolites by proton nuclear magnetic resonance spectroscopy.

RESULTS

Significantly lower values for several key metabolites were found in patients with low back pain or sciatica, with the lowest values in the subgroup of patients with myelographic signs of disc protrusion or herniation.

CONCLUSIONS

The results indicate a higher level of metabolic activity in patients with low back pain or sciatica compared with pain-free control subjects, with this difference being most pronounced in the subgroup of patients with myelographic evidence of disc protrusion or herniation.

Evidence for a possible synergism between pituitary adenylate cyclase activating polypeptide and calcitonin gene-related peptide in porcine ophthalmic artery

The activities of pituitary adenylate cyclase activating polypeptide (PACAP) and calcitonin gene-related peptide (CGRP) were investigated in isolated segments of porcine ophthalmic artery. In artery segments pre-contracted by prostaglandin F2alpha, PACAP induced a concentration dependent relaxation, but was clearly less potent than CGRP. When 2 x 10(-10) M CGRP (relaxation 4.3 +/- 0.8%, n = 11) and 10(-8) M PACAP (relaxation 12.4 +/- 3.8%, n = 10) were added together, the subsequent relaxation was substantially increased (33.6 +/- 5.6%, p<0.0005). In addition, the rate of relaxation was increased. The results indicate that there is synergism between low concentrations of CGRP and PACAP in isolated porcine ophthalmic artery.

Smoking history in middle age and subsequent cognitive performance in elderly Japanese-American men. The Honolulu-Asia Aging Study

The associations between cigarette smoking history and later cognitive performance were examined among 3,429 Japanese-American participants of the Honolulu Heart Program (HHP) and its extension, the Honolulu-Asia Aging Study (HAAS). Cognitive performance was measured by the Cognitive Abilities Screening Instrument (CASI), administered as part of HAAS (mean age at HAAS exam (standard deviation (SD)): 77.7 (4.6) years). Information on smoking history was collected during the first and third HHP exams (mean age (SD) at Exam III: 58.6 (4.7) years). Compared with never-smokers, those who had smoked continuously between Exams I-III and those who had quit smoking during that period had significantly lower CASI scores, after adjustment for age, education, Japanese acculturation, and Exam III alcohol intake. In multiple logistic regression controlling for the above covariates, a significantly higher risk of cognitive impairment (CASI score < 82) was associated with continuous smoking (odds ratio (OR) = 1.36, 95% confidence interval (CI) 1.10-1.69) and quitting between Exams I-III (OR = 1.36, 95% CI 1.03-1.80) compared with never smoking. This excess risk of cognitive impairment among continuous smokers and Exam I-III quitters was slightly diminished by further adjustment for body mass index and several vascular covariates. Additional analyses suggested a reduced risk of cognitive impairment among the longer-term quitters. This study suggests a positive association between smoking during middle age and later risk of cognitive impairment.

NMR spectroscopy study of the effect of 3-nitropropionic acid on glutamate metabolism in cultured astrocytes

3-Nitropropionic acid (3-NPA) is a selective and irreversible inhibitor of succinate dehydrogenase. The effect of this compound on the metabolism of [U-13C]glutamate was studied in astrocytes using 13C nuclear magnetic resonance spectroscopy. The appearance of [1,2,3-13C]glutamate in cell extracts and [1,2,3-13C]glutamine and [U-13C]lactate in cell media demonstrated the metabolism of labeled glutamate via the tricarboxylic acid cycle. Such labeling was observed in the control situation and also in cells treated with 3 mM 3-NPA. In the cells treated with 3 mM 3-NPA, however, the labeling was significantly reduced, and with 10 mM 3-NPA no such labeling was observed. Labeled aspartate was observed in untreated cells only. Labeled succinate was not detectable under control conditions, but increased dose dependently in the presence of 3-NPA. Glutamate uptake and conversion of [U-13C]glutamate to [U-13C]glutamine was largely unaffected by 3-NPA, and ATP content was unchanged. In a previous study using cerebellar neurons, tricarboxylic acid cycle metabolism was blocked with 3 mM 3-NPA. The present results show that astrocyte metabolism is more adaptable to blockade of the tricarboxylic acid cycle by 3-NPA than neuronal metabolism.