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The hindlimbs of the Malayan sun bear (Helarctos malayanus), the polar bear (Ursus maritimus), the brown bear (Ursus arctos) and the giant panda (Ailuropoda melanoleuca) have been anatomically and osteometrically studied. The Musculus tibialis cranialis of the Malayan sun bear and the giant panda possessed a well-developed rich fleshy portion until the distal end of the tibia. In the polar bear and the brown bear, however, the fleshy portion of the M. tibialis cranialis was not developed until the distal end of the tibia. The tendon of the M. tibialis cranialis inserting on the proximal end of the Ossa metatarsalia was shorter in the Malayan sun bear and the giant panda than in the polar bear and the brown bear. In the Malayan sun bear and the giant panda, moreover, the M. popliteus was attached more distally to the tibia than in the polar bear and the brown bear. The stable dorsiflexion and supination of the foot and the efficient pronation of the crus are important for skillful tree climbing. The present study suggests that the Malayan sun bear and the giant panda have hindlimbs especially adapted to tree climbing by the well-developed fleshy portion of the M. tibialis cranialis reaching the distal end of the tibia, its short tendon, and the M. popliteus inserting near the distal end of the tibia.

We examined the geographical variation of the skull size and shape of the lesser mouse deer (Tragulus javanicus) from Laos, Thailand, Peninsular Malaysia, Sumatra, Java, Borneo, Langkawi and some Islands of Tenasserim in Myanmar. Although the influence of the climatic condition on skull size was not confirmed in the mainland populations, the skull became rostro-caudally longer in the populations of Tenasserim and Sumatra because of island isolation effect. The skull size was classified into the following three clusters of localities from the matrix of Q-mode correlation coefficients: 1) Langkawi and Tenasserim, 2) Laos and Thailand, 3) Sumatra and Borneo. The skulls in the population of Java belong to the cluster of Langkawi and Tenasserim in male, however were morphologically similar to those in the cluster of Borneo and Sumatra. The canonical discriminant analysis pointed out that the Laos and Tenasserim populations were separated from the other ones and that the populations of Sumatra, Java and Borneo were intermingled each other.

The geographical variations of the skulls were osteometrically examined in the gray-bellied squirrel (Callosciurus caniceps) from the populations of Korat, Ranong, southernmost Thailand, and Terutau Island. The skull size was larger in northern population than in the southern population in the continental mainland. The zoogeographical influences of the Isthmus of Kra remained unclear, since the plots from Korat population were intermingled with those from southernmost Thailand population in the principal component charts. Although Korat population has been thought to belong to north group, we suggest that Ranong and southernmost Thailand populations may contain individuals from both north and south groups separated by the ancient Kra barrier. Terutau Island population was similar to southernmost Thailand population in skull size, although Terutau population has been isolated in the island and separated from the south group of the Isthmus of Kra. In the proportional analysis the interorbital space was narrower and the binocular sense has been well-developed in Terutau population. It suggests that this population has been highly adapted to arboreal behavior. In contrast, the skull with larger interorbital space was more adaptive for terrestrial life in Korat population. The canonical discriminant analysis could clearly separate the four populations in the scattergrams of discriminant scores.

The skull adaptation was functional-morphologically examined in 14 species of the tree shrews. From the data of the proportion indices, the similarities were confirmed between T. minor and T. gracilis, T. tana and T. dorsalis, and T. longipes and T. glis. We demonstrated that the splanchnocranium was elongated in terrestrial T. tana and T. dorsalis and shortened in arboreal T. minor and T. gracilis from the proportion data. In both dendrogram from the matrix of the Q-mode correlation coefficients and scattergram from the canonical discriminant analysis, the morphological similarities in the skull shape suggested the terrestrial-insectivorous adaptation of T. tana and T. dorsalis, and the arboreal adaptation of T. minor and T. gracilis. Since the osteometrical skull similarities were indicated among the three species of Tupaia by cluster and canonical discriminant analyses, the arbo-terrestrial behavior and its functional-morphological adaptation may be commonly established in T. montana, T. longipes and T. glis.

ZD1839 ('Iressa') is an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that inhibits EGFR signaling. Emerging evidence indicates that ZD1839 has clinical potential in lung cancer, but very little is known about the molecular characteristics of lung cancers that may determine sensitivity to ZD1839. We examined a panel of 19 lung cancer cell lines to investigate possible association between ZD1839 sensitivity and histological type, expression level and constitutive phosphorylation of EGFR and K-ras gene status. Our results indicate that neither expression level nor constitutive activation status of EGFR seems to predict sensitivity to ZD1839. In addition, ZD1839 sensitivity was not associated with expression of human epidermal growth factor receptor-2 (HER-2), another member of this tyrosine kinase receptor family nor with co-expression of EGFR and HER-2. Finally, no correlation was found between the presence of activating mutations of the K-ras gene, an important downstream mediator of the EGFR-transduced signals and the relative resistance to ZD1839. These findings warrant future study to clarify how ZD1839 inhibits lung cancer cell growth and to find a useful marker for prediction of sensitivity to this novel and promising agent for the treatment of lung cancers.

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.

The morphological differences in the muscles of mastication between the giant panda (Ailuropoda melanoleuca) and the Asiatic black bear (Ursus thibetanus) were sought to confirm the adaptational strategy of these muscles in the giant panda. We measured some skull characteristics and weighed the muscles of mastication, and macroscopically observed the muscles of mastication in the two species. The noticeable differences between the two species are classified as follows: (1) The size ratio of the zygomatic width was much larger in the giant panda than in the Asiatic black bear. (2) The weight ratio of the two pterygoid muscles was also much larger in the giant panda than in the Asiatic black bear. (3) The lateral slips of the temporal muscles are thicker and stronger in the Asiatic black bear than in the giant panda. (4) The deep layer of the masseter muscle was rostrocaudally divided, and a complicated running of tendons is observed in the giant panda. (5) The two pterygoid muscles were much larger and well-developed in the giant panda than in the Asiatic black bear. The points (1) and (4) may be related to the generation of the force necessary to chew the bamboo in the giant panda. We thought that the large mass of the masseter and temporal muscles are needed in this species. In the points of (2) and (5), the two pterygoid muscles were obviously different in form and weight ratio between the two species. We suggest that the two pterygoid muscles may act as an additional force generator to dorsoventrally press and crush bamboo stems.

Sympatric populations of the genus Tupaia encompassing two cytotypes (cyt60, 2n = 60 and cyt62, 2n = 62) were found in the southern part of the Isthmus of Kra (the middle region of the Malay Peninsula, Thailand). C-bands, location of rDNA, and location of non-essential telomeric repeats (TRs) were investigated in detail for 23 animals captured in the area. Such chromosomal traits definitely reveal that two distinct cytotypes exist in the sympatric population, though the external morphological traits are similar. Hybrid cytotypes were not observed; thus, these two cytotypes appear to be genetically isolated sibling species. Chromosomal results compared with previous data, geographic distribution and morphological data observed with new insight suggest that, in the sympatric population, 'cyt60' represents members of Tupaia glis, while 'cyt62' identifies individuals of Tupaia belangeri. The cytogenetic information discovered in the present study offers new insight to morphological classification and, further, may provide substantial diagnostic characteristics for the distinction of tree shrew species.