Yasuhisa Yasuda

Supplementation effect of early pregnancy factor-positive serum into bovine in vitro fertilization culture medium.

PROBLEM: Early pregnancy factor (EPF) has been detected in pregnant bovine serum, and its activity appeared from 24 to 48 hr after insemination. However, in bovine in vitro fertilization (IVF), an EPF‐like substance(s) had been detected in the culture medium of fertilized ovum. Therefore, we think that EPF and EPF‐like substance(s) are very important materials for the development of the embryo. In this study, we examined the development of the embryo when fertilized bovine ova were cultured with IVF culture medium supplemented with EPF‐positive or ‐negative serum.

An Oil-Cooled Flash X-Ray Tube For Biomedical Radiography

The construction and the applications of an oil-cooled flash x-ray tube to biomedical radiography are described. Generally, this tube was used for the repetitional flash x-ray generator for producing soft x-rays and consisted of the following major parts: a vacuum vessel made of stainless steel with a diameter of 80mm, a ring cathode made of molybdenum of 0.2mm thickness, a rod-shaped anode tip made of tungsten with a diameter of less than 3.0mm for obtaining the high intensity x-rays, an anode rod made of beryllium-copper alloy utilizing cooling fins, an internal x-ray output made of copper having a cooling mechanism, and an air-cooled heat exchanger. The anode tip was mounted on the anode rod and could easily be changed, and the cathode was attached to the internal output mouth of x-rays. The anode-cathode plane space was adjusted from the outside of the x-ray tube by rotating the x-ray diaphragm. The operating voltage was less than 150kV, and the maximum tube current was more than lOkA. The effective focal spot size primarily varied according to the diameter of anode tip and it ranged from 0.5 to 3.0mm in diameter. This tube was connected to two types of high-voltage pulsers: (a) a high voltage repetitional pulser achieved with a frequency control system of less than 20Hz, and (b) a Cockcroft circuit with a high-frequen-cy DC-AC inverter. Various radiographs were obtained by using this tube in conjunction with these pulsers.

A Flash Radiographic System For Biomedical Use

A flash radiographic system utilizing a single flash x-ray generator having a new kind of combined x-ray tube and a computed radiography (CR) system is described. This system consisted of the following components: two types of delay switches (i. e. (a) direct switching and (b) laser switching), a delayed pulse generator, a CR system, and a high-intensity single flash x-ray generator. This generator consisted of the following components: a high-voltage generator, a high-voltage pulser, a vacuum pump, and a new type of combined remote x-ray tube with two sets of anode and cathode electrodes. When the radiographic object triggered the timing switch, a short electric pulse was produced and was transmitted to the delayed pulse generator. An accurate delayed flash x-ray was produced when the delayed pulse was transmitted to the high-speed impulse switching system inside of the high-voltage pulser. Next, when the radiographic object was exposed to the controlled x-rays under the optimum radiographic conditions, the permeating x-rays produced the digital image. The FX pulse widths were less than 10Ons with a photon energy of less than 120keV. Since the time resolutions for the two types of delay switches were less than 2Ons, the total time resolution for the FX production was less than 1ps. Various kinds of high-speed biomedical radiography, e. g., the continuous delayed radiographs and the continuous three-dimensional analysis could be performed by controlling the radiographic conditions.

Scanning Electron Microscopic Studies of Uterine Epithelial Cytoplasmic Protrusions: Effects of Ovarian Hormones in Ovariectomized Rat Uterus

受精卵の着床時における子宮粘膜上皮細胞の役割と子宮粘膜上皮細胞の表面に出現する細胞質突起に対する卵巣ホルモンの役割を明らかにするために,卵巣摘出ラットにプロジェステロンとエストロジェンを投与して,子宮粘膜上皮細胞表面の細胞質突起の出現とその数,大きさおよび形状について走査型電子顕微鏡を用いて経時的に観察を行なった.両側卵巣摘出後,ホルモン無処理の動物およびエストロンのみ投与の動物ではまったく細胞質突起は出現しない.しかし,プロジェステロンの連続投与によって細胞質突起が出現し,さらにエストロンを投与することによって,投与6時間後に有意にその数は増加し,18時間まで数は変化しないが,24時間あるいは48時間後にその数は減少する.細胞質突起の形状は一般に水胞状を呈するものが多いが,エストロン投与後12時間ではロゼット形成をしているものが多く,24ないし48時間では粘膜上皮細胞表面の粗造化によって,細胞質突起の形状は不鮮明となる.エストロン投与12時間後に子宮に物理的刺激を加えるとその6時間後の子宮粘膜上皮細胞表面の形態は変化し,細胞質突起は急激に減少する.これらの結果は,子宮粘膜上皮細胞表面の細胞質突起が卵巣ホルモン,すなわちプロジェステロンとエストロジェンの協同作用によって出現することを示している.また,子宮粘膜上皮表面に多くの細胞質突起が出現しているとぎに子宮に物理的刺激を与えると細胞質突起は急速に消失することから,この細胞質突起は子宮の脱落膜形成に関与しているものと考えられる.