[Case of carbon monoxide poisoning with delayed encephalopathy assessed by magnetic resonance imaging].

A 21-year-old man attempted suicide by burning charcoal in a car for more than one day and was admitted to a regional hospital. On admission, his blood carboxyhemoglobin concentration was 4.4%. The patient was transferred to our emergency department because of suspected carbon monoxide poisoning. Hyperbaric oxygen therapy (HBO) was performed 5 times over 3 days. Fluid-attenuation inversion recovery (FLAIR) and diffusion-weighted (DWI) magnetic resonance imaging (MRI) performed on day 3 showed high signal-intensity lesions in the cerebral white matter. Additional HBO was performed once per day until day 16. Wecheler Memory Scale-Reviced (WMS-R) and Mini-Mental State Examination (MMSE) performed on day 17 showed his cognitive impairment. He gradually recovered the cognitive function and was discharged from the hospital without neurological sequelae on day 49. Delayed encephalopathy after acute carbon monoxide poisoning with dementia, mental impairment, and psychosis is a serious complication. Hyperintensity in FLAIR and DWI MRI predicts delayed encephalopathy and indicates cellular edema and demyelination of the white matter. One of the risk factors is prolonged carbon monoxide exposure. This case suggests that the patient, who was exposed to carbon monoxide for many hours, was at a high risk of delayed encephalopathy despite the low blood carboxyhemoglobin concentration and therefore must be monitored using MRI.

[Binocular diplopia and ptosis due to snakebite (Agkistrodon blomhoffi "mamushi")--a case report].

We treated a patient who developed binocular diplopia and ptosis after being bitten by an Agkistrodon blomhoffi (mamushi). The patient was a 49-year-old man who presented with binocular diplopia after the snakebite on the second finger of his right hand. He experienced local pain and swelling and a few hours later, he developed diplopia. In the primary position he had no tropia. On the basis the ocular angle of deviation measured by a Hess chart test, he was diagnosed with paresis of the medial rectus muscle paresis. Binocular diplopia persisted for 2 weeks. The venom of A. blomhoffi venom mainly consists of hemolytic toxins, but it also contains 2 types of neurotoxins--an alpha-toxin and a beta-toxin. Neurotoxins affects the neuromuscular junction (NMJ). The alpha-toxin acts postsynaptic inhibition as a competitive inhibitor of acetylcholine and causes postsynaptic inhibition; these effects are similar to those of the anti-acetylcholine receptor antibody identified in patients with myasthenia gravis. The beta-toxin inhibits acetylcholine release by disrupting the presynaptic membrane, and thus, its effects cannot be blocked by the anticholinesterase edrophonium chloride. Although both antiserum and cepharanthine are widely used for the treatment of snakebites, there is no evidence of a specific effective therapy for the eye manifestation after snakebite. However, it these manifestation improves in about 2 weeks without any specific treatment. Our case suggested that the occurrence of subjective binocular diplopia without objective tropia could be caused by snakebite.

Geographical variation in skull morphology of gray-bellied squirrel Callosciurus caniceps.

The geographical variation of the gray-bellied squirrel (Callosciurus caniceps) was examined using osteometry of skull in Southeast Asia. From the principal component analysis (PCA), the plots of the northern localities from Nan to Kanchanaburi and those of the southern localities from Narathiwat to Kuala Lumpur in male were completely separated. In female, the plots of the locality from Uttradit to Kanchanaburi and those of the locality from Pattani to Negri Sembilan were completely separated. We called these northern localities and southern localities which are distinguished by the PCA as N group and S group. The size and shape of the skulls of these squirrels indicated the differences between N group and S group from t-test and U-test. These results may be influenced by the two transitions of the phytogeography around the southernmost locality in N group and the northernmost locality in S group in the peninsular Thailand and Malay Peninsula. Localities which are located between N and S groups were called the Middle (M) group. From the PCA among N, S groups and each locality of M group, the plots of localities such as Prachuap Khiri Khan, Chumphon, Krabi, Nakhon Si Thammarat and Trang in both sexes of M group could not be separated from those of N and S groups. We suggest that the sympatric distribution of N and S groups and the hybrid of N and S populations may be seen in these localities of M group.

Geographical variation of skull size and shape in various populations in the black giant squirrel.

We osteometrically examined the skulls of the black giant squirrel (Ratufa bicolor) from three mainland populations (M. Malayan Peninsula, V. South Vietnam, and B. Burma, India and North Thailand) and from two island populations (T. Tioman, and S. Sumatra Islands). The skull in the Malayan peninsula population was significantly smaller than that of the two other mainland populations. It is consistent with Bergmann's rule as shown in the gray-bellied squirrel. The two island populations did not show obvious differences in comparison with the Malayan population in many measurements. In the proportion analysis eliminating the size factor, the differences among populations were not easily confirmed and we concluded that the osteological characters peculiar to each population could not be shown in this species. The first and second principal component scores of M, S, and T populations were intermingled, whereas the V and B populations of V and B were not separated in the chart. We pointed out that the morphological differences were demonstrated between northern and southern groups of the Isthmus of Kra in the mainland populations, and that the two island populations did not show the island-isolation effect in comparison with the M population. The adaptational variation related to feeding and locomotion could not be confirmed among populations of the black giant squirrel as shown in the proportion analysis.

Geographical and functional-morphological variations of the skull in the gray-bellied squirrel.

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.

Geographical variation of skull morphology and its functional significances in the red-cheeked squirrel.

Skulls of the red-cheeked squirrel (Dremomys rufigenis) from various geographical locations: Malaysia (peninsular area), Vietnam (south district)-Laos, and Thailand (north district) were osteometrically examined. The skull size of the squirrels in the southern (Malaysia) population was fundamentally larger than that in the northern (Vietnam, Laos and Thailand) populations. The proportion indices indicated that the splanchnocranium was relatively longer in the Malaysia population, and that the interorbital space was narrower in Vietnam-Laos, and Thailand populations. We suggest that the long nose and laterally-oriented orbits in the skull may be better adapted for terrestrial-insectivorous life in the Malaysia population and the binocular sense facilitated by rostrally-oriented eyes contributes to the arboreal-fruit eating behavior in the two northern populations. The Malaysia population was clearly distinguished from the other populations by the principal component analysis. We suggest that the geographical barrier of the Isthmus of Kra influences the morphological variation of the skull among the squirrel populations.

Macroscopic study of the functional significance of the forearm muscles in the giant panda.

The extensor and flexor group muscles and their related muscles were functional-morphologically observed in the dead body of the giant panda to clarify the action of the forearm and the palm in the manipulation of the species. The Musculus flexor carpi ulnaris had two developed heads, however, we can conclude that the contraction of this muscle slightly changes the angle of the accessory carpal bone to the ulna. The data pointed out that the accessory carpal bone acts as a supporting post, when the giant panda seizes the object. The M. abductor digiti I longus possessed the well-developed origin in both ulna and radius. These findings suggest that this muscle may function as a supinator of the forearm. We also suggest that the well-developed M. pronator quadratus and M. pronator teres, and the proximal part of the M. abductor digiti I longus and the M. supinator may efficiently contribute to the pronator-spinator action of the forearm, when the giant panda brings the food to its mouth using the manipulation system equipped in the palm region.