Calcium and phosphorus in aged human cerebral arteries

To elucidate the compositional changes of the cerebral arteries with aging, the authors investigated age-related changes of the calcium and phosphorus contents in the cerebral arteries by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 11 men and 5 women, ranging in age from 52 to 96 yr. The anterior, middle, and posterior cerebral arteries derived from the same subjects were used in the present study. It was found that there were no significant relationships between age and calcium or phosphorus content in the anterior, middle, and posterior cerebral arteries, indicating that the accumulation of calcium and phosphorus scarcely occurred in the anterior, middle, and posterior cerebral arteries with aging. It was examined whether there were relationships in the calcium and phosphorus contents among the anterior, middle, and posterior cerebral arteries. It was found that there was a significant relationship in both the contents of calcium and phosphorus between the middle and posterior cerebral arteries, but not between the anterior and middle cerebral arteries nor between the anterior and posterior cerebral arteries.     

Gender Difference in Accumulation of Calcium and Phosphorus in the Left Coronary Arteries of Thais

To examine whether there were gender differences in compositional changes of the coronary artery with aging, the authors investigated the gender difference in age-related changes of elements in the left coronary arteries of Thais by direct chemical analysis. After ordinary dissections by students at Chiang Mai University were finished, the left coronary arteries were resected from Thai subjects. The Thai subjects consisted of 69 men and 34 women. The ages of the male subjects ranged from 25 to 87?years (average age?=?62.6?±?11.4?years) and of the female subjects from 24 to 86?years (average age?=?59.4?±?14.6?years). After incinerating the arteries with nitric acid and perchloric acid, the element content was determined by inductively coupled plasma-atomic emission spectrometry. The Ca and P contents tended to increase in the left coronary arteries of men with age, but the increases were not statistically significant. In the left coronary arteries of women, the Ca and P contents increased significantly and progressively with aging. In addition, the Na content increased significantly in the left coronary arteries of both men and women with aging. The differences in the average contents of Ca and P by age group were observed between the left coronary arteries of men and women. With Student's t test, significant gender differences in the average contents of Ca and P were found in both the 40s and the 70s. The Ca and P contents of the left coronary arteries in the 40s were significantly higher in men than in women. In contrast, the Ca and P contents in the 70s were significantly higher in women than in men. These results indicated that the accumulation of Ca and P in the left coronary arteries of Thais occurred at least 10?years earlier in men than in women, but a higher accumulation of Ca and P in old age occurred in the left coronary arteries of women compared with those of men. The present study revealed that there were significant gender differences in the left coronary arteries with regard to the accumulation of Ca and P with aging. It is reasonable to presume that taking clinical findings into consideration, the gender differences in the left coronary arteries may result from hormonal and/or genetic factors rather than lifestyle factors.     

Age-dependent Increases of Calcium, Phosphorus, and Sodium in the Uterine Arteries of Thai

To elucidate compositional changes of the uterine artery with aging, the authors investigated age-related changes of elements in the uterine arteries of Thai. After ordinary dissection by medical students at Chiang Mai University was finished, the uterine arteries were resected from Thai subjects. Thai subjects ranged in age from 27 to 86 years (average age = 63.3 +/- 17.7 years). The element content of the uterine arteries was analyzed by inductively coupled plasma-atomic emission spectrometry. It was found that the Ca, P, and Na contents increased progressively in the uterine arteries of Thai with aging. A significant accumulation of Ca and P in the uterine arteries of Thai was found in the sixties patients, and the accumulation increased markedly in the seventies. Regarding the uterine arteries in subjects more than 60 years, the extent of accumulation of Ca and P in the uterine arteries of Thai was one half of that in the uterine arteries of Japanese. Regarding the relationships among elements, extremely significant direct correlations were found among the contents of Ca, P, Mg, Zn, and Na in the uterine arteries of Thai. As Ca increased in the uterine arteries of Thai, P, Mg, Zn, and Na increased simultaneously in the arteries.     

Blood vessel size of circulus arteriosus cerebri (circle of Willis): a statistical research on 100 human subjects

The brain weight of 100 fresh cadavers of Italian subjects (60 males and 40 females), aged between 17 and 84 years, was obtained and the corrected circumference of the following blood vessels was measured: basilar artery, internal carotid arteries, anterior and posterior cerebral arteries, and anterior and posterior communicating arteries. The cerebral 'potential flow' was expressed in each case by adding the circumference of the basilar artery to that of the internal carotid arteries. Moreover, the sides and the perimeter of the circle of Willis as well as the length of the basilar artery were calculated. The statistical analysis of the obtained data yielded the following main results: (1) the brain weight decreases with aging, is lower in females than in males and and is statistically correlated neither with the circumferences of the considered arteries and the 'potential flow' nor with the perimeter of the arterial polygon (circle of Willis); (2) the arteries of the left side appear to be larger than those of the right one; (3) no significant difference exists in the circumference and length of the arteries between males and females; (4) the increase of the perimeter of the arterial polygon is achieved by means of a harmonious increase of all its sides; (5) the anterior and posterior communicating arteries have an anarchic pattern, because of the relatively frequent anomalies and the lack of a correlation between their circumference and that of the vessel of origin or of outlet.     

Increases of calcium and phosphorus in the uterine arteries with aging

To elucidate compositional changes of the uterine artery with aging, the authors investigated age-related changes of elements in the uterine arteries. After ordinary dissection by medical students at Nara Medical University was finished, the uterine arteries were resected from the subjects. The element content of the uterine arteries was analyzed by inductively coupled plasma-atomic emission spectrometry. The subjects ranged in age from 58 to 99 yr (average age=82.7±10.1 yr). It was found that the Ca, P, and Na contents increased progressively in the uterine arteries with aging. A significant accumulation of Ca and P in the uterine arteries was found in the sixties and increased markedly in the eighties. It should be noted that as far as the arteries in those over 70 yr of age, the extent of accumulation of Ca and P was the highest in the uterine arteries within the limits of the arteries analyzed by us. Regarding the relationships among elements, significant direct correlations were found among the contents of Ca, P, Mg, Zn, and Na. As Ca increased in the uterine arteries, P, Mg, Zn, and Na increased simultaneously in the arteries.     

Differences in calcium accumulation between human plantar and palmar aponeuroses

To elucidate the characteristics of calcium accumulation of human plantar and palmar aponeuroses, the authors determined the calcium content of human plantar and palmar aponeuroses by atomic absorption flame emission spectrophotometry. The subjects consisted of 9 men and 14 women, ranging in age from 61 to 93 yr. In the plantar aponeurosis, the calcium content was significantly higher in the anterior and posterior parts than in the middle part. It is known that pressure distribution under the sole of a foot is higher in the anterior and posterior parts than in the middle part. The present study suggests that the accumulation of calcium in the plantar aponeurosis is related with the pressure distribution under the sole of a foot. The calcium content increased progressively with aging in the anterior part of the plantar aponeurosis, but not in the middle and posterior parts. Regarding the palmar aponeurosis, the calcium content was significantly higher in the anterior and posterior parts in comparison with the middle part. It was found that the calcium content increased progressively with aging in the posterior part of the palmar aponeurosis, whereas it did not increase significantly with aging in the anterior and middle parts. Regarding the relationship between the calcium content of the aponeuroses and the bone mineral density, a significant correlation was found between the calcium content in the anterior part of the palmar aponeurosis and the bone mineral density of the scaphoid bone.     

树鼩(Tupaia belangeri chinensis)的脑底动脉环

用25只树鼩,从升主动脉灌注带色的橡胶乳液,在解剖显微镜下进行解剖观察,用目测微尺进行测量。大多数树鼩(22只)有完整的脑底动脉环。由左、右大脑前动脉向内侧各发一前交通动脉组成大脑前总动脉。前交通动脉口径为大脑前动脉的75～85％。后交通动脉口径与大脑后动脉相近,连于颈内动脉与大脑后动脉(基底动脉的分支)之间。测量了组成脑底动脉环有关动脉的口径。由于后交通动脉足够粗大,只有中断左、右颈总动脉和左、右椎动脉,才能造成全脑缺血。     

Simultaneous accumulation of calcium, phosphorus, and magnesium in various human arteries

To elucidate compositional changes of the arteries with aging, the authors investigated the relationships among average contents of calcium, phosphorus, sulfur, and magnesium in the arteries by inductively coupled plasma-atomic emission spectrometry. The arteries used were the thoracic and abdominal aortas, coronary, common carotid, anterior, middle and posterior cerebral, vertebral, basilar, internal thoracic, axillary, radial, truncus celiacus, common, internal and external iliac, femoral, popliteal, and umbilical arteries. It was found that high correlations were found between the average contents of calcium and phosphorus, between the average contents of calcium and magnesium, and between the average contents of phosphorus and magnesium in the arteries, but not between the average contents of sulfur and the other elements. These correlations revealed that as the content of calcium and phosphorus increased in the arteries, the magnesium content increased simultaneously in the arteries, but the sulfur content did not. It is likely that magnesium forms compounds with phosphorus in the arteries.     

Moderate Accumulation of Calcium and Phosphorus in the Splenic Artery with Aging and Low Accumulation of Those in the Pulmonary Artery with Aging

To elucidate compositional changes of the arteries with aging, the authors investigated age-related changes of elements in the splenic and pulmonary arteries, which supplied blood to contractile organs. After ordinary dissection by medical students at Nara Medical University was finished, the splenic and pulmonary arteries were resected from the subjects, ranging in age from 58 to 94 years. The element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that a moderate accumulation of Ca and P occurred in the splenic artery with aging, but it hardly occurred in the pulmonary artery with aging. Regarding the relationship among elements, the finding that there were significant direct correlations among the contents of Ca, P, Mg, and Na was commonly obtained in both the splenic and pulmonary arteries. The accumulation of Ca and P in the splenic artery with aging occurred independently of that in the pulmonary artery. Histologic observation indicated that a major part of Ca deposits was seen in the middle tunica, but not in the internal tunica. Therefore, the calcification occurring in the splenic artery belonged to middle sclerosis.     

Structure and sympathetic innervation of the intracranial arteries in the giraffe (Giraffa camelopardalis)

Fluorescence histochemistry discloses that the carotid rete mirabile in the giraffe has a poor sympathetic innervation. In contrast, the efferent artery of the rete (internal carotid artery) and the cerebral arteries show moderate sympathetic innervation. A certain degree of regional variability was noted in which the rostral arteries (anterior and middle cerebral) receive more sympathetic nerves than the caudal (posterior communicating and basilar) arteries. The sympathetic nerves on the giraffe cerebral vessels may constitute part of a host of mechanisms by which regional blood flow to the brain is regulated. Conversely, the paucity of sympathetic innervation of the carotid rete mirabile may indicate that this structure does not play an active role in vasoconstrictor responses during postural changes of the head.     

Age-Related Changes of Elements in the Anterior Commissures and the Relationships Among their Elements

To elucidate compositional changes of the anterior commissure with aging, the authors investigated age-related changes of elements in the anterior commissures and the relationships among their elements. After ordinary dissection at Nara Medical University was finished, the anterior commissures were resected from 45 subjects, ranging in age from 70 to 101 years. The subjects consisted of 22 men and 23 women. After ashing with nitric acid and perchloric acid, the element content of the anterior commissures was determined by inductively coupled plasma-atomic emission spectrometry. The seven element contents of Ca, P, S, Mg, Zn, Fe, and Na did not change significantly in the anterior commissures with aging. Regarding the relationships among their element contents, significant correlations were found among the contents of Ca, Mg, Zn, and Na in the anterior commissures. The gender difference that the Zn content was significantly higher in men than in women was found in the anterior commissure.     

川金丝猴脑的动脉供应

为了探讨川金丝猴脑动脉供应的形态学特征,为脑生物学研究提供结构基础,用血管铸型和组织透明方法追踪观察了川金丝猴幼体脑动脉的来源和分支分布。结果表明川金丝猴与人脑的动脉供应基本相同,也由颈内动脉和椎动脉供应。上述动脉的分支于垂体周围形成大脑动脉环。颈内动脉通过大脑前动脉和大脑中动脉主要供应大脑半球前部的血液,椎动脉参与形成基底动脉、小脑动脉系和大脑后动脉,供应脑干、小脑和大脑后部的血液。另外,川金丝猴幼体左、右大脑前动脉间缺少前交通动脉。     

High Accumulation of Calcium and Phosphorus in the Pineal Bodies with Aging

To elucidate compositional changes of the pineal body with aging, the authors investigated age-related changes of elements in the pineal body. After the ordinary dissection by medical students was finished, the pineal bodies and seven arteries were resected from the subjects ranging in age from 58 to 94 years. The element contents were determined by inductively coupled plasma atomic emission spectrometry. It was found that a high accumulation of Ca and P occurred in the pineal bodies with aging. Regarding the relationships among the elements, it was found that there were significant direct correlations among the contents of Ca, P, and Mg. With regard to the relationships between the pineal body and the arteries, no significant correlations were found in the Ca content between the pineal body and the arteries, such as the thoracic and abdominal aortas and the coronary, common carotid, pulmonary, splenic, and common iliac arteries.     

Modelling the circle of Willis to assess the effects of anatomical variations and occlusions on cerebral flows

Blood flow in the circle of Willis (CoW) is modelled using the 1-D equations of pressure and flow wave propagation in compliant vessels. The model starts at the left ventricle and includes the largest arteries that supply the CoW. Based on published physiological data, it is able to capture the main features of pulse wave propagation along the aorta, at the brachiocephalic bifurcation and throughout the cerebral arteries. The collateral ability of the complete CoW and its most frequent anatomical variations is studied in normal conditions and after occlusion of a carotid or vertebral artery (VA). Our results suggest that the system does not require collateral pathways through the communicating arteries to adequately perfuse the brain of normal subjects. The communicating arteries become important in cases of missing or occluded vessels, the anterior communicating artery (ACoA) being a more critical collateral pathway than the posterior communicating arteries (PCoAs) if an internal carotid artery (ICA) is occluded. Occlusions of the VAs proved to be far less critical than occlusions of the ICAs. The worst scenario in terms of reduction in the mean cerebral outflows is a CoW without the first segment of an anterior cerebral artery combined with an occlusion of the contralateral ICA. Furthermore, in patients without any severe occlusion of a carotid or VA, the direction of flow measured at the communicating arteries corresponds to the side of the CoW with an absent or occluded artery. Finally, we study the effect of partial occlusions of the communicating arteries on the cerebral flows, which again confirms that the ACoA is a more important collateral pathway than the PCoAs if an ICA is occluded.     

Age-related changes of elements and relationships among elements in human tendons and ligaments

To elucidate compositional changes of the tendons and ligaments with aging, the authors investigated age-related changes of element contents in the insertion tendons of the biceps brachii muscle, central tendons of the diaphragma, Achilles’ tendons, posterior longitudinal ligaments (PLLs) of the cervical spine, ligamenta capitum femorum, and anterior cruciate ligaments. After ordinary dissections by medical students, the three tendons and three ligaments were resected and element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that the elements, such as Ca, P, S, Mg, Na, Zn, and Fe, did not change significantly in the three tendons and two ligaments with aging, except for the PLLs where Ca and Mg increased significantly with aging and Fe decreased significantly with aging. With regard to the relationships among elements, the common finding that there were significant correlations between Ca and P contents and between Ca and Mg contents was obtained in the three ligaments. Likewise, the common finding that there was a significant correlation between Ca and Mg contents was obtained in the three tendons. Regarding the relationship between Ca and P contents, the three tendons were different from the three ligaments.     

Selected contribution: Effects of aging on cerebrovascular tone and [Ca2+]i.

The lower limits of cerebral blood flow autoregulation shift toward high pressures in aged compared with young rats. Intraluminal pressure stimulates contractile mechanisms in cerebral arteries that might, in part, cause an age-dependent shift in autoregulation. The present project tested two hypotheses. First, cerebral artery tone is greater in isolated arteries from aged compared with mature adult rats. Second, aging decreases the modulatory effect of endothelium-derived nitric oxide (NO) and increases vascular smooth muscle Ca2+ sensitivity. Isolated segments of middle cerebral arteries from male 6-, 12-, 20-, and 24-mo-old Fischer 344 rats were cannulated and loaded with fura-2. Diameter and Ca2+ responses to increasing pressure were measured in HEPES, during NO synthase inhibition [NG-nitro-l-arginine methyl ester (l-NAME)], and after removal of the endothelium. Cerebral artery tone (with endothelium) increased with age. Only at the lowest pressure (20 and 40 mmHg) was intracellular Ca2+ concentration ([Ca2+]i) greater in arteries from 24-mo-old rats compared with the other age groups. l-NAME-sensitive constriction increased significantly in arteries from 6- to 20-mo-old rats but declined significantly thereafter in arteries from 24-mo-old rats. [Ca2+]i was less in arteries from 24-mo-old rats compared with the other groups after treatment with l-NAME. Another endothelial-derived factor, insensitive to l-NAME, also decreased significantly with age. For example, at 60 mmHg, the l-NAME-insensitive constriction decreased from 47 +/- 10, 42 +/- 5, 21 +/- 2, and 3 +/- 1 microm in 6-, 12-, 20-, and 24-mo-old rats, respectively. Our data suggest that aging alters cerebral artery tone and [Ca2+]i responses through endothelial-derived NO synthase-sensitive and -insensitive mechanisms. The combined effect of greater cerebral artery tone with less endothelium-dependent modulation may in part contribute to the age-dependent shift in cerebral blood flow autoregulation.     

Comparison of calcium accumulation between the arteries of human and monkey

To examine whether an accumulation of elements in the arteries was affected by the way of walking, the authors investigated age-related changes of elements in the arteries of the Japanese, Thai, and Japanese monkeys. After the ordinary dissections by medical students were finished, the subclavian, axillary, brachial, radial, common iliac, externaliliac, femoral, and posterior tibial arteries were resected from the subjects of the Japanese and Thai over 60 yr of age and they were also resected from the Japanese monkeys over 20 yr of age. The element content was determined by inductively coupled plasma-atomic emission spectrometry. It was found that in an comparison between the arteries of anatomically corresponding regions, the average content of Ca was eight times or four times higher in the arteries of the lower limb than in the arteries of the upper limb in the Japanese or Thai, over 60 yr of age, respectively. In the Japanese monkeys over 20 yr of age, the average content of Ca was 1.2 times higher in the arteries of the lower limb than in the arteries of the upper limb. The result suggests that an accumulation of Ca in the arteries of the lower limb with aging is affected by the way of walking.     

Effects of hypoxia on contractility of isolated fetal lamb cerebral arteries

We studied the contractile properties of isolated cerebral arteries in near term fetal lambs, as well as the magnitudes and rates of relaxation during moderate hypoxia. Paired 5-mm segments of basilar, middle cerebral, posterior communicating, and common carotid arteries were suspended in a temperature controlled bath and isometric tension measured during 122 mM K(+)-induced contractions. In one vessel of each pair hypoxia was imposed by switching the bubbling gas from 95% O2 + 5% CO2 to 95% N2 + 5% CO2 4 minutes into a K+ contraction, thus lowering the bath PO2 to approximately 15 Torr. After 15 min exposure to hypoxia the middle cerebral artery had relaxed 61%, the posterior communicating 46%, the basilar 44%, and the common carotid only 18% compared to normoxic controls. All cerebral arteries relaxed relatively rapidly (relaxation rates of 42-45 x 10(-4) s-1), whereas the common carotid relaxed slowly (20 x 10(-4) sec-1). The data indicate that these cerebral arteries play an important role in regulating blood flow responses during hypoxemia in intact fetuses.     

Earlier accumulation of calcium, phosphorus, and magnesium in the coronary artery in comparison with the ascending aorta, aortic valve, and mitral valve

To explore reasons for a high accumulation of Ca and P occurring in the coronary artery of Thai with aging, the authors investigated age-related changes of elements in the coronary artery, ascending aorta near the heart, and cardiac valves in single individuals, and the relationships in the elements between the coronary artery and either the ascending aorta or cardiac valves. After an ordinary dissection by medical students at Chiang Mai University was finished, the anterior descending arteries of the left coronary artery, ascending aortas, mitral valves, and aortic valves were resected from the subjects. The subjects consisted of 17 men and 9 women, ranging in age from 46 to 76 yr. The element content was analyzed by inductively coupled plasma-atomic emission spectrometry. The average content of Ca and P was the highest in the coronary artery and decreased in the order aortic valve, ascending aorta, and mitral valve. The Ca, P, and Mg content increased in the coronary artery in the fifties and in the ascending aorta, aortic valve, and mitral valve in the sixties. It should be noted that the accumulation of Ca, P, and Mg occurred earlier in the coronary artery than in the ascending aorta, aortic valve, and mitral valve. It was found that with respect to the Ca, P, Mg, and Na contents, the coronary artery correlated well with both the aortic valve and ascending aorta, especially with the aortic valve, but it did not correlate with the mitral valves. This finding suggests that the accumulation of Ca, P, Mg, and Na occurs in the coronary artery together with the aortic valve and ascending aorta, but not together with the mitral valve. Because regarding the accumulation of Ca, P, and Mg, the ascending aorta and aortic valve are preceded by the coronary artery, it is unlikely that the accumulation of Ca, P, and Mg spreads from the ascending aorta or aortic valve to the coronary artery.     

Hemodynamic role of the circle of Willis in stenoses of internal carotid arteries. An analytical solution of a linear model

A mathematical model of blood flow through the circle of Willis was developed, within a linear framework. Comprehensive analytical solutions, including a remarkably small number of parameters, were derived in the cases of obstructive lesions of extracranial carotid arteries. The influence of these lesions and the role of anterior and posterior communicating arteries on the blood pressure at the entry of the cerebral territories were quantified and analyzed emphasizing that the responses of the system of Willis to obstructive carotid lesions are extremely varied, depending on the communicating artery anatomy. Comparison with numerical results obtained by using a non-linear model showed no physiologically significant differences. Such a model might be an essential tool for an accurate assessment of the cerebral hemodynamics in carotid diseases.