Hiroshi Koie

Role of the giant panda's ‘pseudo-thumb’

The way in which the giant panda, Ailuropoda melanoleuca, uses the radial sesamoid bone — its ‘pseudo-thumb’ — for grasping makes it one of the most extraordinary manipulation systems in mammalian evolution. The bone has been reported to function as an active manipulator, enabling the panda to grasp bamboo stems between the bone and the opposing palm,. We have used computed tomography, magnetic resonance imaging (MRI) and related techniques to analyse a panda hand. The three-dimensional images we obtained indicate that the radial sesamoid bone cannot move independently of its articulated bones, as has been suggested, but rather acts as part of a functional unit of manipulation. The radial sesamoid bone and the accessory carpal bone form a double pincer-like apparatus in the medial and lateral sides of the hand, respectively, enabling the panda to manipulate objects with great dexterity.

CT examination of the manipulation system in the giant panda (Ailuropoda melanoleuca).

The manipulation mechanism of the giant panda (Ailuropida melanoleuca) was examined by means of CT (computed tomography) and 3‐dimensional (3‐D) Volume Rendering techniques. In the 3‐D images of the giant panda hand, not only the bones but also the muscular system was visualised. Sections of the articulated skeleton were obtained. It was demonstrated that the hand of the panda is equipped with separately moulded manipulation units as follows: (1) the radial sesamoid (RS), the radial carpal, and the first metacarpal (R–R–M) complex; and (2) the accessory carpal (AC) and the ulnar (A–U) complex. When the giant panda grasps anything, the R–R–M complex strongly flexes at the wrist joint, the RS becomes parallel with the AC, and the phalanges bend and hold the object. It is shown that the well‐developed opponens pollicis and abductor pollicis brevis muscles envelop and fix the objects between the R–R–M complex and the phalanges during grasping.

Carpal bone movements in gripping action of the giant panda (Ailuropoda melanoleuca)

The movement of the carpal bones in gripping was clarified in the giant panda (Ailuropoda melanoleuca) by means of macroscopic anatomy, computed tomography (CT) and related 3‐dimensional (3‐D) volume rendering techniques. In the gripping action, 3‐D CT images demonstrated that the radial and 4th carpal bones largely rotate or flex to the radial and ulnar sides respectively. This indicates that these carpal bones on both sides enable the panda to flex the palm from the forearm and to grasp objects by the manipulation mechanism that includes the radial sesamoid. In the macroscopic observations, we found that the smooth articulation surfaces are enlarged between the radial carpal and the radius on the radial side, and between the 4th and ulnar carpals on the ulnar side. The panda skilfully grasps using a double pincer‐like apparatus with the huge radial sesamoid and accessory carpal.

Transthyretin amyloidosis and two other aging-related amyloidoses in an aged vervet monkey.

An aged male vervet monkey showed severe cardiac arrhythmia for more than 3 years. A multifocal amyloid consisting of transthyretin was deposited in all areas of the heart wall, especially in the extracellular stroma among muscle fibers and external tunica of arterioles. Moreover, the amyloid was deposited in the stroma and arterioles of other systemic organs except the liver and spleen. These characteristics are consistent with senile systemic amyloidosis in humans. A second amyloid consisting of amyloid β protein was in senile plaques and cerebral amyloid angiopathy in the cerebral cortex. A third amyloid consisting of islet amyloid polypeptide was deposited in islets of the pancreas. Apolipoprotein E and amyloid P component colocalized with the 3 amyloids. Thus, 3 different aging-related amyloids were found in an aged vervet monkey. In particular, to our knowledge, this is the first report on spontaneous transthyretin amyloidosis in animals.

Plasma thrombin- antithrombin complex concentrations in dogs with malignant tumours

IT has been suggested that coagulation abnormalities such as disseminated intravascular coagulation (DIC) might be caused by the excessive activation of coagulation in dogs with malignant tumours (O’Keefe and Couto 1988). Since excessive activation of coagulation leads to over-generation of thrombin, increased concentrations of thrombin measured in circulating blood would indicate an activation of coagulation. Thrombin-antithrombin complexes (TATs), which are formed rapidly after thrombin production, have been identified as a marker of coagulation activation (Pelzer and others 1988). The plasma TAT concentration has been reported to be useful for evaluating the activation of coagulation in dogs (Ravanat and others 1995), and is available as a marker of the hypercoagulable state in dogs with Cushing’s syndrome (Jacoby and others 2001). However, the plasma TAT concentrations in dogs with malignant tumours have not been reported. This short communication describes the plasma TAT concentrations in dogs with benign or malignant tumours and the incidence of a hypercoagulable state in dogs with malignant tumours. The plasma TAT concentrations of three groups of dogs were examined. Group 1 comprised 16 clinically healthy adult dogs; the dogs were considered clinically normal on the basis of physical examination, routine haematological examination and serum biochemical analysis. Group 2 comprised 11 dogs with benign tumours: five with an adenoma, three with a leiomyoma, two with a haemangioma and one with a lipoma. Group 3 consisted of 62 dogs with malignant tumours, this group was further divided into four subgroups: 27 dogs with epithelial tumours, 17 with mesenchymal tumours except haemangiosarcoma; 10 with haemangiosarcomas and eight with haematopoietic tumours. The dogs in groups 2 and 3 were referred to the Animal Medical Center of Nihon University and their tumours were diagnosed by histopathological examination. None of the dogs received any anticoagulants or blood products before blood sampling. Blood samples were collected into tubes containing 0·13M trisodium citrate (nine parts blood to one part anticoagulant) and centrifuged at 2000 g for 10 minutes, and the citrated plasma was frozen at –30°C until analysis. The plasma TAT concentrations were measured by enzyme immunoassay (TAT Test Kokusai-F; International Reagents Corporation). Mann-Whitney U tests were used to compare plasma TAT concentrations between the groups. For statistical analysis, plasma TAT concentrations undetectable by the assay method used (<0·4 ng/ml) were regarded as 0·4 ng/ml. To detect the incidence of a hypercoagulable state, a reference range of plasma TAT concentration was established as the mean (2sd) concentration obtained from group 1. Dogs with plasma TAT concentrations above the reference range were regarded as displaying a hypercoagulable state. The median (range) plasma TAT concentrations were 0·5 (<0·4 to 0·6) ng/ml in group 1, 0·4 (<0·4 to 6·3) ng/ml in group 2 and 1·3 (0·4 to 49·3) ng/ml in group 3; concentrations were significantly higher in group 3 than in group 1 (P<0·0001). However, there was no significant difference in the plasma TAT concentrations of groups 1 and 2 (P=0·8823) (Fig 1). Within group 3, the TAT concentrations were 0·8 (0·4 to 3·8) ng/ml for the dogs with epithelial tumours, 0·7 (0·4 to 49·3) ng/ml for those with mesenchymal tumours, 17·3 (4·4 to 42·5) ng/ml for those with haemangiosarcomas, and 8·2 (2·1 to 19·0) ng/ml for those with haematopoietic tumours. The plasma TAT concentrations were significantly elevated in all subgroups of group 3 (P<0·001, P<0·01, P<0·0001 and P<0·0001, respectively) compared with group 1 (Fig 2). The mean (2sd) plasma TAT concentration of dogs in group 1 was 0·49 (0·12) ng/ml, and thus dogs with plasma TAT concentrations in excess of 0·61 ng/ml were considered as disVeterinary Record (2005) 156, 839-840

Spontaneous Osteosarcoma in a Rabbit (Oryctolagus cuniculus)

A 6-year-old male cross-breed rabbit (Oryctolagus cuniculus) was presented with lameness and severe swelling from the right shoulder to brachium. On 16-detector helical computed tomography images of the amputated right forelimb after being fixed in formalin, evident proliferative and destructive lesions of bone were observed. On histologic examination, the tumor was composed of proliferating neoplastic cells that resembled histiocytes, with abundant osteoid production. A large number of multinucleated giant cells were found throughout. This case was diagnosed as osteosarcoma by clinical, radiographic, and histologic findings. This is a rare case report of osteosarcoma in a rabbit consistent with canine predilection sites.

Three-Dimensional CT Examination of the Mastication System in the Giant Anteater

Abstract The gross anatomy of the mastication system of the giant anteater (Myrmecophaga tridactyla) was examined by means of three-dimensional image analysis. The anteater rotates the mandibles medially and laterally to control its tongue when it is elongated and to house it when it is relaxed. Three-dimensional CT image analysis demonstrated that the shape and size of the oral cavity changes drastically when the mandibles are rotated. The oral cavity expands bilaterally when the dorsal part of the mandibles bend medially. Macroscopic observations and muscle-weight data supported the observation that the superficial temporal and medial pterygoid muscles act as the main medial and lateral rotators of the mandible, respectively. The low height of the mandibular ramus and the incomplete zygomatic arch in this species represent adaptations for the rotational movement of the mandibles, since they both contribute to the medially oriented transmission of force from the temporal muscles and to preventing collision between the mandibles and the cranium during the rotational movement.

Three-dimensional CT image analysis of the digging system in the aardvark

We examined the bone movement in the forepaw and hind paw in the aardvark (Orycteropus afer) by using three-dimensional (3D)-computed tomography (CT) techniques and osteometrical methods to confirm the functional adaptation of the extremities as a digging system. The four metacarpal bones could be strongly bent from the distal carpal bones. The distal end of the second and third metacarpal bones possessed enlarged smooth articulation surfaces that allowed the proximal phalanx to bend at a sharp angle. However, the articulation surface was not well-developed in the distal end of the fourth and fifth metacarpal bones and the proximal phalanx could bend at smaller angle in these two lateral digits. The proximal phalanges sharply crook from the metatarsal in the first, second, third and fourth digits in the hind paw. We suggest that the medial two digits in the forepaw directly contribute to the crushing, when these proximal phalanges crook in the phase of power stroke. In contrast the lateral third and fourth digits may act as sweeper of the crushed soil. These suggestions regarding the different functional adaptation between medial two digits and lateral two digits are consistent with the anatomical data of the forearm musculature. In the hind paw, we suggest that the second, third and fourth digits are functionally similar and that the hind paw may not act as a crushing apparatus but as a running motor or soil-sweeper similarly using these main three digits.

Three-Dimensional Reconstruction of the Xenarthrous Process of the Thoracic and Lumber Vertebrae in the Giant Anteater

Abstract. The presacral vertebra of anteaters was examined by three-dimensional CT image analysis of the xenarthrous processes peculiar to the Order Xenarthra. The anteater is equipped with two following articulations in addition to the normal zygapophysial articulation. The dorsal xenarthrous process of the former vertebra articulates to the ventral area of the base of the mammillary process in the later vertebra. The pocket-like structure in the ventral area of the mammillary process receives the dorsal and ventral xenarthrous processes of the former vertebra. The complicated articulations do not obstruct the ability of the giant anteater to flex dorsally and laterally, however aids flexibility and strengthens the caudal thoracic and lumber regions of the animal. The xenarthrous processes and articulations may function as a supporter of the body weight during the bipedal standing posture when the anteater destroys the nests of ants and termites and protects itself from the enemies.

Regeneration of intervertebral disc by the intradiscal application of cross-linked hyaluronate hydrogel and cross-linked chondroitin sulfate hydrogel in a rabbit model of intervertebral disc injury

The degeneration of intervertebral disc (IVD) is a major cause of low back pain. However, there is no satisfactory preventive treatment for degenerative disc disease (DDD). In this study, we examined the effects of a novel cross-linked hyaluronate hydrogel and cross-linked chondroitin sulfate (CS) hydrogel on a rabbit model of IVD injury. We injected 300 microl of phosphate buffer saline, 1% sodium hyaluronate, cross-linked hyaluronate hydrogel, or cross-linked CS hydrogel into the injured IVDs. One, three or six months after treatment, the whole spinal columns were dissected and magnetic resonance (MR) images of the IVDs were examined. It was noted that the IVD, which was injected with cross-linked hyaluronate hydrogel or cross-linked CS hydrogel mostly retained the normal signal intensity of the MR images. These IVDs exhibited a higher degree of staining with safranin-O than the control discs or 1% sodium hyaluronate-injected discs, suggesting that the intradiscal application of cross-linked hyaluronate hydrogel or cross-linked CS hydrogel probably inhibits the degenerative cascade of the DDD. The intradiscal administration of these drugs is safe, easy and costs less. In the near future, these intradiscal injections may become the standard therapy for the treatment of DDD instead of the spine surgeries.