Histopathological studies on Osseous Tissue in Newborn Infants with Special Reference to Correlation between the Development of Organs and Osseous Tissue in Various Regions.
The present study was carried out on a total of 133 autopsy cases derived from dead fetuses and dead newborn infants collected at the First Department of Pathology, over a period of ten years. These cases were examined morphopathologically to clarify the degree of differentiation of osseous tissue in femur, sternum, rib, lumbar vertebra, and cranium.
1. The osseous tissus of each bone was differentiated in proportion to the number of weeks of fetal life. Differentiation tended to begin at the 37 th week of fetal life. Rib and sternum showed still a somewhat low degree of differentiation at the 37 th week of fetal life and tended to become differentiated regularly in the following week. Of the cranial bones, the frontal bone was much less differentiated than the occipital and temporal bones at the 26 th week of fetal life. It began to be come differentiated rapidly at the 28 th week.
2. The correlation between the differentiation of osseous tissue and the body weight at the time of birth was examined. As a result, the lighter the body weight was, the lower the degree of differentiation of this tissue was in the infant. There was a tendency for this tissue to be differentiated in almost all the infants weighing 2, 200 gm. at the time of birth.
3. When the number of weeks of fetal life was equal, the larger the number of days of survivial, the higher the degree of differentiation of osseous tissue.
4. Even when the number of weeks of fetal life was equal, the heavier the body weight at the time of birth, the higher the degree of differentiation.
5. In fetuses affected with pulmonary atelectasis, hyaline-like membrane degeneration, serious deformity, and intracranial hemorrhage, the differentiation of esseous tissue was low in degree. There was no specific correlation between any other pathological change and the differentiation of osseous tissue.
6. The less advanced the development of organs, the lower the degree of differentiation of osseous tissue. The more persistent the extramedullary hematopoietic focus, the lower the degree of differentiation of osseous tissue.
7. Myeloid cell began to decrease in the 33 rd week, and nucleated erythrocytes began to decrease in the 38 th week. Thereafter they both tended to increase again.
Myeloid cells, lymphocytes, reticular cells, and monocytic cells were higher in count, but nucleated erythrocytes were rather lower in the group of infected fetuses than in that of noninfected fetuses.
From the results mentioned above, it is presumed that the degree of differentiation of osseous tissue is related mutually to the state of development of organs in the newborn infant.
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