Kohzo Tsuchikawa

Three-dimensional observation of the mouse embryo by micro-computed tomography: composition of the trigeminal ganglion

The purpose of this study was to demonstrate a micro-computed tomography (CT) method for observations of the mouse embryo. At 13.0 days post-coitum, mouse embryos were fixed in 4% paraformaldehyde for 24 h and stained en bloc by osmium tetroxide overnight. The embryos were then embedded in paraffin using standard methods for 24 h. Specimens were analyzed by micro-CT and image processing was performed. Organs containing nervous and blood systems could be viewed as a result of different osmium-staining densities. The trigeminal ganglion was imaged using three-dimensional techniques. Observation of the embryo was possible by micro-CT with osmium tetroxide staining.

Embryological study of the development of the rat temporomandibular joint: highlighting the development of the glenoid fossa

Basic embryological findings on the development of the temporomandibular joint have yet to be elucidated sufficiently. This experiment, was undertaken to find the standard time course of the development of the temporomandibular joint in rat fetuses. Serial frontal and sagittal sections of rat fetal heads (between 13.5 and 20.5 days post-conception [p.c.]) were examined microscopically. The condyle was recognized as a mesenchymal condensation at 14.5 days p.c., while the glenoid fossa was recognized at 15.5 days p.c. The mesenchymal condensation of the condyle had differentiated into chondrocytes by 16.5 days p.c., and endochondral ossification was recognized at 17.5 days p.c. The intramembranous ossification of the glenoid fossa was already recognized by 16.5 days p.c.; this started in the posterior region and progressed anteriorly between the zygomatic arch and the squamous part of the temporal bone. Ossification of the condyle had not been completed by 20.5 days p.c., a mass of hypertrophic chondrocytes remained in the center of the condylar head. The glenoid fossa was almost completely ossified by 19.5 days p.c. A coarse region of cells, reminiscent of apoptosis, was recognized in the region of the prospective superior joint space at 17.5 days p.c., and an actual joint space had formed by 18.5 days p.c. The inferior joint space was recognized at 19.5 days p.c. as a fissural cavity, but it was much narrower than its superior counterpart. The prospective meniscus was distinguished on the condylar surface at 17.5 days p.c. by the difference in the shape of its constituent cells. The results obtained here seem to be useful for further experiments and molecular biological studies.

Clinical evaluation of urinary 6-hydroxymethylpterin (6-HMP) in patients with cancer of the digestive organs

The purpose of this study is to clarify the clinical significance of urinary 6-HMP in patients with cancer of the digestive organs. High-performance liquid chromatography (HPLC) was used to determine 6-HMP in first morning urine. Conclusions were as follows:1.Cut off level of urinary 6-HMP was defined as 0.079 μg/ml, from 87 normal subjects.2.The daily profile of urinary 6-HMP in normal subjects was highest in morning and lowest at bedtime and daily changes were continuously under the cut off level.3.Sensitivity, specificity and accuracy of urinary 6-HMP were 64.2%, 77.6% and 70.5% respectively.4.In patients with malignant diseases, the overall positive rate was 64.2% and was clearly higher than benign diseases.5.The positive rate of urinary 6-HMP levels in malignant diseases was highest in pancreatic cancer (75.0%) and lowest in hepatocellular carcinoma (55.8%).6.Urinary 6-HMP elevated several days after operation and returned within normal range after 2–3 weeks.7.Urinary 6-HMP concentration correlated to the therapeutic effects of anticancer drugs, and increased again in tumor recurrence.

The effect of angiotensin II on the proliferation of human gingival fibroblasts

Angiotensin not only raises blood pressure and modifies body fluids and electrolytes but also induces differentiation and proliferation of fibroblasts in the circulatory system in order to repair damage. The purpose of the present study was to observe the influence of the addition of angiotensin II (AngII) or nifedipine (NIF) alone or both sequentially on proliferative activity, the intracellular Ca2+ concentration ([Ca2+]i), and the inositol-1,4,5-triphosphate (IP3) level in cultivated human gingival fibroblasts. Addition of 10−8−10−4 M NIF or 10−5−10−4 M AngII alone increased the proliferation of cultivated gingival fibroblasts, and the interaction of NIF and AngII suppressed proliferation. Addition of AngII alone increased [Ca2+]i, with a peak 60 s afterward and a return to a level slightly higher than the pretreatment level at 120 s. Addition of both AngII and NIF did not increase [Ca2+]i as much as the addition of AngII alone. When Ca2+ was absent from the extracellular environment, the AngII-induced increase in [Ca2+]i was suppressed. AngII increased the concentration of IP3, with a peak at 120 s after its addition. From these results we concluded that AngII increased the proliferation of gingival fibroblasts by causing an influx of Ca2+, which increased [Ca2+]i.

Histological Investigation of the Development of the Anlage of the Mandibular Condyle of Mouse

Abstract To elucidate the histological findings of the anlage of the mandibular condyle during very early developmental stages, we analyzed sagittal and frontal plane serial sections of mouse fetuses for which the gestational period was precisely determined. An aggregate of mesenchymal cells around the buccal nerve (peripheral cell aggregate) could be seen at 12.0 days post-conception (dpc). Another cell aggregate (core cell aggregate), which almost coincided with the outline of the condylar head, was detected on the inside of the dome-shaped peripheral cell aggregate at 12.75 dpc. The cells of the peripheral cell aggregate were gradually flattened in accordance with cell differentiation, and formed a fibrous sheath covering the condylar head by 15.0 dpc. The cells of the central region of the core cell aggregate differentiated into hypertrophic chondrocytes by 14.5 dpc, whereas the cells of the fringe of the core cell aggregate differentiated into osteogenic cells to form the bone collar by 15.0 dpc. The continuity of the anlage of the condyle with that of the mandibular ramus was first recognized at 13.0 dpc. As the anlage of the mandibular condyle was observed histologically during very early developmental stages, further research is necessary to characterize the development of this anlage in greater detail.

Experimental analysis of the chemically induced carcinoma. The 1st experiment. 1. Gross and microscopic observation, postulated the two range passway for the carcinoma.

This chemically induced carcinogenesis experiment was performed for purposes of preliminary experimenting for further oral carcinoma studies. Painting 0.5% DMBA in liquid paraffin into six-week-old Golden Syrian Hamsters buccal pouches, threetimes a week for 14 weeks, the following results were elucidated.Within the first 4 weeks, inflammatory reactions of the mucosa, i. e., redness, formation of plaques, and bleeding were found. Thereafter, they naturaly disappeared from around the 5th to the 6 th experimental weeks. On the 8 th week, papillomatous tumors suddenly appeared which were growing gradually in size, number, and even in atypism. The surrounding epithelia showed changes comparable to epithelial dysplasia or carcinoma in situ. It was from the 12-week-painted group that well-differentiated squamous cell carcinomas were-first recognized.These tumors were rather exophytic growths and showed a minimal invasive trend. However, invasive tumors were formed as well in the 14-week-painted group. Therefore, two possible ways for carcinoma formation might be suggested. One is from papilloma through increased atypism, such as verrucous carcinoma, and the other from epithelial dysplasia or carcinoma in situ with downward growth of the rete-processes to the carcinoma.