Hideo Tamate

Stimulatory effect of insulin on ruminal epithelium cell mitosis in adult sheep.

1. The rumen adapts to increased food intake by the hyperplasia of epithelial cells. 2. Volatile fatty acids (VFA) stimulate cell mitosis of sheep ruminal epithelium in vivo. 3. Since VFA generally inhibit cell proliferation in vitro insulin was proposed in this study as the possible mediator of the mitotic stimulation in vivo. 4. Infusions (6 h) of insulin (0.125 U/kg per h) plus glucose (300 mg/kg per h) (n 5), and glucose alone (300 mg/kg per h) (n 2) resulted in higher mitotic index of biopsied rumen epithelium (MI) during 3 or 6 to 24 h after the start of infusion, and higher plasma immunoreactive insulin (IRI) and higher plasma glucose (PG) during the infusion. 5. Insulin plus glucose infusion showed higher MI, higher IRI, and lower PG than glucose infusion. 6. Sheep infused with saline for 6 h (n 1) showed no marked changes in MI, IRI, and PG. 7. Increased IRI by insulin plus glucose or glucose alone infusion was considered to stimulate cell proliferation in rumen epithelium. 8. Other possible mediations were discussed.

Distribution of myofiber types in thigh muscles of chickens

The composition of myofiber types varies within thigh muscles of chickens. The present study was designed to determine whether or not myofiber types were distributed uniformly across the diameter of the thigh muscles of chickens. Cross sections from middle portions of muscles were used histochemically to examine differences in distribution and composition of myofiber types in the muscles. Myofibers that reacted moderately (M) or strongly (S) for myosin adenosine triphosphatase (ATPase) after preincubation at pH 4.3 were classified as type I. Type I myofibers reacted weakly (W), moderately (M), or strongly (S) for ATPase after preincubation at pH 10.6; these type I myofibers were subclassified into four types (ISW, ISM, ISS, and IMM). Myofibers that reacted negatively for acid‐stable ATPase and strongly for alkali‐stable ATPase were classified into two types: type IIA, with strong NADH tetrazolium reductase (NADH‐TR), and type IIB, with weak NADH‐TR activity. The M. pubo‐ischio‐femoralis pars lateralis had numerous type IIA myofibers and very few type ISM myofibers, whereas the pars medialis had many type IMM myofibers and few type ISS and IIA myofibers. The type I group of myofibers did not exceed about 50% in the other muscles, which had one to three types of type ISW, ISM, and ISS myofibers. The Mm. femorotibiales had more type ISW, and ISM myofibers in the deep regions near the femur than in the superficial regions. The M. iliotibialis cranialis, M. iliofibularis, and M. flexor cruris medialis had more type ISW, ISM, or ISS myofibers in the medial regions than in the lateral regions. A few type ISW myofibers were scattered in the cranial part of M. iliotibialis and in the M. ambiens. The M. flexor cruris lateralis pars pelvica had type IIA and IIB myofibers exclusively. All the muscles had type IIA myofibers. Type IIB myofibers existed in the muscles except the M. puboischio‐femoralis. Type IIA and IIB myofibers differed in proportion in different muscles and in their different regions. The type I group of myofibers was generally concentrated more in the deep regions near the femur and in the medial regions than in the superficial and lateral regions of the thigh muscles. The distribution of type IIA myofibers resembled that of type I group. Type IIB myofibers showed a distribution opposite to that of type I group and IIA myofibers. The spatial distribution of myofiber types within individual muscles can account for the various locomotory and postural requirements of the thigh.

Cell deletion as a factor in the regulation of rumen epithelial populations

When the feed of sheep was changed from hay to barley, there were hyperplastic changes in the ruminal epithelium. These were characterised by an increase in the rate of mitosis and by a very low incidence of single cell death (apoptosis). A subsequent abrupt change of diet from barley to hay resulted in atrophy of the ruminal epithelium. Atrophy was associated with a fall in the rate of mitosis, and a rise in the incidence of apoptosis which together caused regression of epithelial pegs. It is suggested that apoptosis may play an important role in the regulation of rumen epithelial cell populations and in the control of epithelial cell kinetics.

Immunocytochemical Study on the C Cells in Pig Thyroid Glands

The distribution of pig thyroid C cells was demonstrated by a immunoperoxidase method using antiserum to porcine calcitonin. The average number of C cells per 4 mm2 counted in the deep and superficial regions was 127 and 55, respectively. The number in the cranial, middle and caudal regions was 60, 128 and 83, respectively. The number of C cells per follicular and C cells (C cell concentration) in deep and superficial regions was 4.9 and 2.6%. It was 3.2, 4.9 and 3.3% in the cranial, middle and caudal regions, respectively. These results indicate that the number and concentration of C cells were not only larger in deep than superficial regions but also in the middle region than in cranial and caudal in pig thyroid gland. These results also indicate that the C cell distribution in pig thyroid gland is the same as that of dog, human, cat, rat, guinea pig, and mouse.

A stathmokinetic study on the ruminal epithelium of sheep.

The metaphase arresting method using colchicine was applied to a kinetic study of the proliferation of sheep ruminal epithelium. Mitotic rate, calculated from the regression coefficient of the metaphase accumulation, was 0.0025 mitoses/cell per hour. Assuming the cell cycle time is about 24 hours as reported by Goodlad (1981), the growth fraction was calculated to be about 9%. The validity of the stathmokinetic method for ruminal cell kinetics is discussed.

Mucosubstance Histochemistry of the Gastric Mucosa in Ungulates

種の有蹄類・ウシ, ヤギ, ヒツジ, ニホンジカ, クビワペッカリー, カバおよびウマの胃粘膜の粘液物質についてアルシアンブルー (pH 2.5) 一過ヨーソ酸シッフ反応 (AB-PAS) と高鉄ジアミンーアルシアンブルー (pH 2.5) 染色 (HID-AB) を用いて組織化学的に調べた, 今回調べた7種の有蹄類では酸性粘液物質が多く見られた. すなわち, 反芻亜目ではスルフォムチンが多く, イノシシ亜目では中性粘液物質に加えシアロムチンやスルフォムチンも多く見られた. ウマでは中性粘液物質とシアロムチンが観察された, これらの動物はいずれも草食性か繊維質食をともなう雑食性であることから, 酸性粘液物質の存在は草食性と関係すると推察された.

The occurrence of paranuclear vacuoles in sheep ruminal epithelium treated with distilled water in vitro and from sheep injected with a large quantity of water into the rumen

In the histological preparation taken after animal death, paranuclear vacuoles (PV) in sheep ruminal epithelium were already present in high percentage (7.5–20.3%). With the incubation of the ruminal mucosae in distilled water (10–15°C) up to 120 min, PV occurrence did not alter. With incubation in NaCl solution, however, PV value decreased with time proportional to NaCl concentration (0.5, 0.85 or 1.5%). In the preparation taken by biopsy, on the other hand, PV were rare in ruminal epithelium (<0.3%). With the injection of warm water (10–141/ animal), however, PV occurrence in the ruminal epithelium was not affected. PV as cytoplasmic processes of the ruminal Langerhans cells are probably formed by the reaction of these cells to environmental changes in the tissue caused by animal death.

Development of Skeletal Muscle Fibers in the Musculus Complexus of the Chick

鶏の錯綜筋(M. complexus)は通称破殼筋(hatching muscle)と呼ばれ,胚発生後期から孵化時にかけて著しい肥大を示し,孵化後急激に萎縮する特殊な筋組織である.本研究は本筋と他の筋の胚発生過程での発達を比較するため組織学的考察を試みたものである.得られた結果は以下の諸点である.(1) 胚発生過程の錯綜筋の筋重量,比体重値は孵卵16日以後増大し,20日で最大となる.孵化後両値は急激に減少する,胚の浅胸筋も孵卵日齢とともに筋重量を増加するが,錯綜筋の場合と異なり,比体重値は次第に減少する.(2) 錯綜筋の筋横断面積は筋重量,比体重値の変化と平行し,孵卵20日に最大値を示す.大腿二頭筋の筋横断面積は孵卵14日まで錯綜筋の値を凌ぐが,16日以後の増加は少ない.(3) 錯綜筋を構成する筋線維の線維径の変化は筋重量,比体重値,筋横断面積の変化と平行している.一方本筋に含まれる筋線維の総数は孵卵16日齢でほぼ最大値に達しており,その後の孵卵日齢や孵化後雛で測定された値に大きな変動がない.(4) 錯綜筋の胚発生後期から孵化時にかけての顕著な肥大現象は,他の筋との比較により明らかとなったが,その主な原因は本筋を構成する筋線維自体の肥大である.

A Histochemical Study on Glycogen Deposits in Sheep Kidney

腎臓の糖原沈着は正常な動物では胎生期や幼若期の集合管にみられ,尿細管の発達に関与している.一方,成育した動物ではこの糖原沈着は一般に観察されないと報告されている.しかし,ヒトや動物では糖原病や尿細管アシドーシス症で,近位尿細管やヘレンのわなの太い部分に糖原沈着が観察されている.めん羊では糖原病の報告はあるが,腎臓の糖原沈着の記載はない.この研究では,授乳中の子めん羊と成育しためん羊の腎臓,さらに成育しためん羊で酪酸を血中より投与した腎臓の糖原沈着について組織化学的に比較した.授乳中め子めん羊では,集合管に多量の糖原沈着が観察された.成育しためん羊では少量の糖原沈着が集合管とヘンレのわなの太い部分に観察された.一方,酪酸を投与されためん羊では著しい糖原沈着がヘンレわなの太い部分に,中等度の糖原沈着が集合管に観察された.以上の結果より,めん羊の集合管にみられた糖原沈着は幼若期では尿細管の発達と深い関係をもち,成長とともに減少すると思われる.一方,ヘンレのわなにみられた糖原沈着は酪酸投与によって多量に観察されることから,酪酸によって起こされたアシドーシスによる糖代謝異常が原因ではないかと考えられる.

Occurrence of rumen parakeratosis in the cattle fed high-concentrateration.

体重370～405kgの和牛5頭を用い,6ヶ月間の粗飼料無給与肥育試験を行なつた.実験飼料は市販の肉牛仕上げ用で,トウモロコシ20%,マイロ25%等を主とする濃厚飼料のみより成つている.試験終了時に第1胃粘膜2ヶ所についてその形態を観察し,さらに組織学的観察をも行なつた.第1胃粘膜では,その半絨毛の軟弱徒長,縁切れ,欠損,尖端部の異常肥厚,黒色化または白色化,粘膜の色調変化(白色斑)等が見られた.組織学的には第1胃粘膜上皮の異常角化と核保有が目立ち,脱落も多かつた.これらの所見から,5頭中2頭(4号牛,5号牛)で軽度ながらRumen parakeratosisの発生を確認し,他の3頭も組織学的な見地から本症とみとめられた.試験期間の後半,4号牛は体重増加せず,5号牛では体重が減少した.これらの成績から,粗飼料無給与によるRumen parakeratosis(第1胃不全角化症)の発生と,その発生による肥育成績の低下とが示唆された.