Ohtsuka, Aiji

Among the 3 mitogen-activated protein kinases -- ERK, p38 MAPK and JNK -- JNK has been suggested to participate in apoptosis, whereas p38 MAPK is thought to be part of the differentiation response. There are many common inducers of JNK and p38 MAPK, but the mechanisms underlying the differential response to apoptosis and differentiation are poorly understood. We found that heatshock activated p38 MAPK at 3min after exposure to a temperature of 44 in stress-hypersensitive PC12m3 mutant cells, while it activated JNK at 20min after the same heat treatment. However, heat shock activated p38 MAPK 5min after heat treatment and JNK 10min after heat treatment in PC12 parental cells. The extent of phosphorylation of p38 MAPK induced by heat shock in PC12m3 cells was significantly greater than that in PC12 parental cells, and a high level of heat-shock-induced neurite outgrowth was observed only in PC12m3 cells. On the other hand, heat-shock-induced JNK activation appeared more quickly and apoptosis started earlier in PC12 parental cells. These findings indicate that short stress induces p38 MAPK and longer stress induces JNK, and that the response of these kinases to heat shock differs depending on cell type.

The skeletal muscle is classified into 2 types, slow oxidative or fast glycolytic muscle. For further characterization, we investigated the capillary architecture in slow and fast muscles. The rat soleus and extensor digitorum longus (EDL) muscles were used as representatives of slow and fast muscles, respectively. To investigate capillary density, sections of both types of muscle were stained with alkaline phosphatase;the soleus muscle showed more intense reactivity, indicating that it had a denser capillary structure than the EDL muscle. We then injected fluorescent contrast medium into samples of both muscle types for light and confocal-laser microscopic evaluation. The capillary density and capillary-to-fiber ratio were significantly higher, and the course of the capillaries was more tortuous, in the soleus muscle than in the EDL muscle. Capillary coursed more tortuously in the soleus than in the EDL muscle. Succinate dehydrogenase (SDH) activity, an indicator of mitochondrial oxidative capacity, and vascular endothelial growth factor (VEGF) expression were also significantly higher in the soleus muscle. Thus, we conclude that slow oxidative muscle possess a rich capillary structure to provide demanded oxygen, and VEGF might be involved in the formation and/or maintenance of this highly capillarized architecture.

We biomechanically evaluated the bone fixation rigidity of an ONI plate (Group I) during fixation of experimentally created transcondylar humerus fractures in cadaveric elbows, which are the most frequently observed humeral fractures in the elderly, and compared it with the rigidity achieved by 3 conventional fixation methods:an LCP reconstruction plate 3.5 using a locking mechanism (Group II), a conventional reconstruction plate 3.5 (CRP) with a cannulated cancellous screw (Group III), and a CRP with 2 cannulated cancellous screws (CS) in a crisscross orientation (Group IV). In the axial loading test, the mean failure loads were:Group I, 98.9+/-32.6;Group II, 108.5+/-27.2;Group III, 50.0+/-7.5;and Group IV, 34.5+/-12.2 (N). Group I fixations failed at a significantly higher load than those of Groups III and IV (p0.05). In the extension loading test, the mean failure loads were:Group I, 34.0+/-12.4;Group II, 51.0+/-14.8;Group III, 19.3+/-6.0;and Group IV, 14.7+/-3.1 (N). Group IV fixations showed a significantly lower failure load than those of Group I (p0.05). The fixation rigidities against mechanical loading by the ONI plate and LCP plate were comparable. These results suggested that an ONI system might be superior to the CRP and CS method, and comparable to the LCP method in terms of fixation rigidity for distal humerus fractures.

A rare anomaly of the scalenus muscles is described. In this case, the right scalenus anterior muscle was absent. As a substitute for this muscle, some aberrant muscle slips arose from the lower vertebrae and descended in front of the ventral rami of the lower cervical nerves. These aberrant slips then ran between the ventral rami of the the eighth cervical and first thoracic nerves, and were fused with the right scalenus medius muscle. Thus, the subclavian artery and vein ran in front of the aberrant slips, together with the ventral ramus of the first thoracic nerve. The aberrant muscle slips issued 2 accessory bundles. One bundle ran between the ventral rami of the fourth and fifth cervical nerves and was fused with the scalenus medius muscle; the other bundle ran between the ventral rami of the fifth and sixth cervical nerves and was fused with the scalenus medius muscle.

The present study showed that many neurons in the adult rat brain possessed a perineuronal sulfated proteoglycan surface coat which reacted to cationic iron colloid and aldehyde fuchsin. This surface coat was stained supravitally with Ehrlich's methylene blue and doubly stained with Ehrlich's methylene blue and aldehyde fuchsin. The surface coat was also stained with Gomori's ammoniacal silver and doubly stained with Gomori's ammoniacal silver and cationic iron colloid. The surface coat was usually expressed together with a nerve cell surface glycoprotein net detectable with lectin Wisteria floribunda agglutinin. These findings indicate that the perineuronal proteoglycan surface coat is identical to Cajal's superficial reticulum and contains some collagenous elements. It was further demonstrated that collagenase digestion erased Gomori's ammoniacal silver impregnation within the perineuronal proteoglycan surface coat.

The accessory ascending cervical artery (Murakami et al., 1996), which arises from the subclavian artery and ascends between the scalenus anterior and medius muscles, was studied in 87 Japanese adult cadavers (174 sides), with special attention being given to its origin, distribution, and relationship to other arteries at the cervical or scalenus region. In 154 sides (88.5%), the accessory ascending cervical artery was found to originate from the subclavian artery behind the scalenus anterior muscle, and to branch out to the scalenus anterior and medius muscles as well as those entering the 5th and 6th intervertebral foramens along the 6th and 7th cervical nerves. This artery arose independently in 105 sides. The accessory ascending cervical artery issued off or formed a common trunk with the transverse cervical artery and/or costocervical trunk in 49 sides. In cases lacking the accessory ascending cervical artery, it was usually compensated for by the costocervial trunk and/or transverse cervical artery (18 sides). Common trunk formation with the vertebral, internal thoracic, or suprascapular arteries was not observed. The authors suggest that the accessory ascending cervical artery, the transverse cervical artery, and the costocervical trunk should be grouped into one arterial system, a system that may be a remnant of the precostal longitudinal anastomoses of intersegmental arteries of the dorsal aorta behind the scalenus anterior muscle.

The celiac and mesenteric arterial system including the left gastric, splenic, common hepatic, and superior mesenteric arteries shows various types of origins, courses, ramifications and anastomoses. In order to explain the various expressions of this system, we have proposed a typological model, in which celiacomesenteric arteries develop as paired or bilaterally symmetrical primordial vessels originated from the anterior aspect of the aorta, and these vessels anastomose each other with longitudinal and horizontal pathways. Here, we report 3 unusual cases characterized by arterial rings, formed by the left gastric, left accessory hepatic, proper hepatic, anterior pancreaticoduodenal, and dorsal pancreatic arteries. The dorsal pancreatic and anterior pancreaticoduodenal arteries are located to the right and left of the embryonic pancreas developing in the dorsal mesentery, respectively. Such hepatopancreatic arterial rings simultaneously containing right and left elements can only be explained using our typological model, in which the concept of paired arteries or bilateral symmetry is introduced.

Two previously unknown anomalies of the anterior intercostobrachial nerve were described. In one case, the anterior intercostobrachial nerve penetrated the pectoralis minor muscle. In the other case, it penetrated the pectoralis major muscle. In both cases, the anomalous nerve supplied the skin of the upper arm.

Mast cells in osteoarthritic and rheumatoid arthritic synovial tissues of the human knee.

Some rare anomalies of the celiaco-mesenteric system were observed postmortem in a Japanese adult male: a) The left gastric, common hepatic, splenic and superior mesenteric arteries arose independently from the abdominal aorta. b) The anterior inferior pancreaticoduodenal artery of the superior mesenteric artery issued a hepatic artery which ascended along the anterior surface of the pancreas and gave off the right gastroepiploic, right gastric and cystic arteries. c) The common hepatic artery gave off an anastomosing branch to the superior mesenteric artery. d) The left gastric artery gave off the left accessory hepatic artery. e) The splenic artery issued the accessory middle colic artery. f) The left inferior phrenic artery gave off the esophageal branch. These anomalies are discussed in light of a typological system which we proposed in a previous paper for the celiaco-mesenteric system.

Origins and distribution of the human inferior phrenic arteries were studied by dissecting 68 Japanese adult cadavers. The inferior phrenic arteries were usually observed as paired (left and right) vessels. Their origins were summarized as follows: a) the aorta itself (85/138 cases, 61.6%), b) the ventro-visceral arteries (celiaco-mesenteric system of the aorta) including the celiac trunk (39/138 cases, 28.2%) and the left gastric artery (4/138 cases, 2.9%), and c) the latero-visceral arteries (adreno-renal system of the aorta) including the middle adrenal artery (4/138 cases, 2.9%) and the renal artery (6/138 cases, 4.3%). The left and right arteries occasionally originated in common trunk from the aorta, celiaco-mesenteric system or adreno-renal system (22/138 cases, 15.9%). A typological diagram explaining these variations is given. The inferior phrenic arteries, especially the left ones, sometimes issued visceral or esophageal branches. This fact indicates that the inferior phrenic arteries are homologous with the celiac trunk and mesenteric arteries. It is further discussed that the celiac trunk and mesenteric arteries are originally paired vessels, through introduction of our previous typological diagram of the abdominal arteries.

Neurons with strongly negatively charged surface coats were recognized in mammalian, avian, reptilian, amphibian and piscine brains. Many large-sized neurons had strongly negatively charged surface coats in the visual cortex and brain stem of the cow, cat, guinea pig, mouse, quail and parakeet. Such neurons were also seen in the brain stem of the lower vertebrates such as the house lizard, Japanese terrapin, bullfrog, newt, carp and sweetfish.