Age-related decrease of the phosphorus content in the ligamentum capitis femoris of monkeys.

To elucidate compositional changes of the ligament with aging, the authors investigated age-related changes of elements in the ligamentum capitis femoris (LCF) of monkeys with a wide range of ages by direct chemical analysis. Used rhesus and Japanese monkeys consisted of 9 males and 22 females, ranging in age from newborn to 31 years (average age = 10.4 ± 10.9 years). After incineration with nitric acid and perchloric acid, element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that the P content decreased significantly in the LCFs of monkeys with aging, but other six element contents, Ca, S, Mg, Zn, Fe, and Na, did not change significantly with aging. Assuming that the P content indicated the active cell density and the S content indicated the protein amount, an age-related change of the mass ratio of P/S was examined in the LCFs. The mass ratio of P/S decreased significantly in the LCFs in childhood. Regarding the relationships among elements, significant direct correlations were found among the Ca, P, S, and Mg contents in the LCFs. It was suggested that the active cell density of the connective tissue cells might decrease significantly in the LCF in childhood.

Gender differences in the phosphorus content of the sino-atrial nodes and other cardiac regions of monkeys.

To examine whether there were gender differences in the sino-atrial node (SAN), the authors investigated the gender difference in the SAN using monkey hearts by direct chemical analysis from a viewpoint of element contents. The used rhesus and Japanese monkeys consisted of 30 males (average age=6.5±7.5 years) and 30 females (average age=12.2±10.3 years), ranging in age from newborn to 30 years. The SAN tissues were removed from the anatomical position of monkey hearts and were confirmed by means of histological observation. After ashing with nitric acid and with perchloric acid, element contents of the SANs, such as Ca, P, S, Mg, Zn, Fe, and Na, were determined by inductively coupled plasma-atomic emission spectrometry. In addition, gender differences in the right atrial walls, left ventricular walls, mitral valves, and left coronary arteries of monkeys were also investigated as controls. It was found that the P content was significantly higher in females than in males in the SANs of monkeys, but the other six element contents, Ca, S, Mg, Zn, Fe, and Na, were not significantly different between males and females in the SANs of monkeys. Regarding the P content, a similar finding was also obtained in both the right atrial walls and the left ventricular walls of monkeys, but it was not obtained in the mitral valves and the left coronary arteries of monkeys. The P content of tissue is mostly determined by the nucleic acid (DNA and RNA) content and the phospholipid content of tissue. Nucleic acids in the cell nucleus and the cytosol, and phospholipids in the cell membrane are all indicators of metabolically active cells. It is reasonable to presume that the P content in the SAN indicates the active cell density, namely, the number of active cells per volume. Therefore, there is a possibility that the active cell density of the SAN is significantly higher in females than in males.

Age-related changes of elements in the tendons of the peroneus longus muscles in Thai, Japanese, and monkeys.

To elucidate compositional changes of the tendon of the peroneus longus muscle with aging, the authors investigated age-related changes of elements in the insertion of tendons of the peroneus longus muscle (peroneus longus tendons) in Thai, Japanese, and monkeys and the relationships among element contents by direct chemical analysis. After ordinary dissections at Chiang Mai University and Nara Medical University were finished, the peroneus longus tendons were resected from the subjects. The peroneus longus tendons were also resected from rhesus and Japanese monkeys bred in Primate Research Institute, Kyoto University. The wraparound regions of the insertion tendons of the peroneus longus muscle in contact with the cuboid bone were used as the peroneus longus tendon. After ashing with nitric acid and perchloric acid, element contents were determined with an inductively coupled plasma-atomic emission spectrometer. It was found that there were no significant correlations between age and the seven elements, such as Ca, P, S, Mg, Zn, Fe, and Na, in the peroneus longus tendons of Thai and Japanese. The Ca content higher than 10 mg/g was contained in seven cases out of 34 peroneus longus tendons of Thai (incidence = 20.6%) and in one case out of 22 peroneus longus tendons of Japanese (incidence = 4.5%), respectively. All of the peroneus longus tendons with the Ca content higher than 10 mg/g were found in Thai and Japanese men. In the peroneus longus tendons of monkeys, the Ca and P content increased suddenly at 2 years of age and reached to about 40 mg/g at 5 years of age. Thereafter, the Ca and P content did not increase in the peroneus longus tendons of monkeys at old age. Regarding the relationships among element contents, significant direct correlations were found among the contents of Ca, P, Mg, Zn, and Na in Thai and monkeys, whereas significant inverse correlations were found between S and element contents, such as Ca, P, Mg, Zn, and Na, in Thai and monkeys.

Expression of FOXP2 in the developing monkey forebrain: comparison with the expression of the genes FOXP1, PBX3, and MEIS2.

By using the developing monkey brain as a model for human development, we investigated the expression pattern of the FOXP2 gene, a member of the FOX family of transcription factors in the developing monkey brain, and compared its expression pattern with transcription factors PBX3, MEIS2, and FOXP1. We observed FOXP2 mRNA expression in several brain structures, including the striatum, the islands of Calleja and other basal forebrain regions, the cerebral cortex, and the thalamus. FOXP2 mRNA was preferentially expressed in striosomal compartments during striatal development. The striosomal expression was transient and developmentally down-regulated in a topographical order. Specifically, during the perinatal state, striosomal FOXP2 expression was detected in both the caudate nucleus and the putamen, although expression was more prominent in the caudate nucleus than in the putamen. Striosomal FOXP2 expression declined during the postnatal period, first in the putamen and later in the caudate nucleus. During the same period, we also detected PBX3 mRNA in the striosomal compartment of the developing monkey striatum. FOXP2, as well as PBX3 and MEIS2, was expressed in the islands of Calleja and other cell clusters of the basal forebrain. FOXP2, in combination with PBX3 and MEIS2, may play a pivotal role in the development of striosomal neurons of the striatum and the islands of Calleja.

Age-dependent decreases of calcium, phosphorus, sulfur, and zinc in the cardiac valves of monkeys.

To elucidate compositional changes of the cardiac valves in monkey with aging, the authors investigated age-related changes of elements in the four cardiac valves of rhesus and Japanese monkeys and the relationships among elements by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The four cardiac valves of the aortic, pulmonary, mitral, and tricuspid valves were resected from 19 rhesus and 11 Japanese monkeys, ranging in age from 10 d to 33 yr. The element contents were determined by ICP-AES. It was found that the Ca, P, S, and Zn contents were high in the four cardiac valves of the monkeys below 1 yr and thereafter decreased significantly with aging, except for Ca in the mitral valve, for which no significant correlation was found between age and Ca content. The Ca and P contents did not increase in the four cardiac valves at old age. This result revealed that calcification scarcely occurred in the four cardiac valves at old age. With regard to the relationships among elements, it was found that there were significant direct correlations among the Ca, P, S, and Zn contents in all of the four cardiac valves of the monkeys, with two exceptions between P and Zn contents in both the aortic and pulmonary valves. Therefore, as Ca decreased in the four cardiac valves, P, S, and Zn decreased simultaneously in the same cardiac valves.