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M Nakatsukasa

Publications and source records attributed to M Nakatsukasa.

At least 19 recordsLinked to original sources
PubMed2006

Energy expenditure of bipedal walking is higher than that of quadrupedal walking in Japanese macaques.

The authors previously compared energetic costs of bipedal and quadrupedal walking in bipedally trained macaques used for traditional Japanese monkey performances (Nakatsukasa et al. 2004 Am. J. Phys. Anthropol. 124:248-256). These macaques used inverted pendulum mechanics during bipedal walking, which resulted in an efficient exchange of potential and kinetic energy. Nonetheless, energy expenditure during bipedal walking was significantly higher than that of quadrupedal walking. In Nakatsukasa et al. (2004 Am. J. Phys. Anthropol. 124:248-256), locomotor costs were measured before subjects reached a steady state due to technical limitations. The present investigation reports sequential changes of energy consumption during 15 min of walking in two trained macaques, using carbon dioxide production as a proxy of energy consumption, as in Nakatsukasa et al. (2004 Am. J. Phys. Anthropol. 124:248-256). Although a limited number of sessions were conducted, carbon dioxide production was consistently greater during bipedal walking, with the exception of some irregularity during the first minute. Carbon dioxide production gradually decreased after 1 min, and both subjects reached a steady state within 10 min. Energy expenditure during bipedalism relative to quadrupedalism differed between the two subjects. It was considerably higher (140% of the quadrupedal walking cost) in one subject who walked with more bent-knee, bent-hip gaits. This high cost strongly suggests that ordinary macaques, who adopt further bent-knee, bent-hip gaits, consume a far greater magnitude of energy during bipedal walking.

Animals↗
PubMed2004

Energetic costs of bipedal and quadrupedal walking in Japanese macaques.

We investigated the energetic costs of quadrupedal and bipedal walking in two Japanese macaques. The subjects were engaged in traditional bipedal performance for years, and are extremely adept bipeds. The experiment was conducted in an airtight chamber with a gas analyzer. The subjects walked quadrupedally and bipedally at fixed velocities (<5 km/hr) on a treadmill in the chamber for 2.5-6 min. We estimated energy consumption from carbon dioxide (CO2) production. While walking bipedally, energetic expenditure increased by 30% relative to quadrupedalism in one subject, and by 20% in another younger subject. Energetic costs increased linearly with velocity in quadrupedalism and bipedalism, with bipedal/quadrupedal ratios remaining almost constant. Our experiments were relatively short in duration, and thus the observed locomotor costs may include presteady-state high values. However, there was no difference in experimental duration between bipedal and quadrupedal trials. Thus, the issue of steady state cannot cancel the difference in energetic costs. Furthermore, we observed that switching of locomotor mode (quadrupedalism to bipedalism) during a session resulted in a significant increase of CO2 production. Taylor and Rowntree ([1973] Science 179:186-187) noted that the energetic costs for bipedal and quadrupedal walking were the same in chimpanzees and capuchin monkeys. Although the reason for this inconsistency is not clear, species-specific differences should be considered regarding bipedal locomotor energetics among nonhuman primates. Extra costs for bipedalism may not be great in these macaques. Indeed, it is known that suspensory locomotion in Ateles consumes 1.3-1.4 times as much energy relative to quadrupedal progression. This excess ratio surpasses the bipedal/quadrupedal energetic ratios in these macaques.

Animals↗
PubMed1999

Ruptured anterior communicating artery aneurysm encased in a tuberculum sellae meningioma. Case report.

This 70-year-old woman suffered a subarachnoid hemorrhage (SAH) from a ruptured anterior communicating artery aneurysm encased in a meningioma in the tuberculum sellae. Although preoperative magnetic resonance imaging disclosed that the aneurysmal complex was completely enclosed in the tumor, angiographic studies did not reveal arterial narrowing. The embedded aneurysm caused diffuse SAH rather than intratumoral hemorrhage. These factors indicated very little adhesion between the tumor and the encased arteries. Surgery was performed on the 20th day post-SAH. Intraoperative findings revealed that the tumor did not adhere to the enclosed vasculature except at the point of rupture of the aneurysm. The authors were able to clip the aneurysm safely after piecemeal removal of the tumor, which was finally extirpated without fear of aneurysm rupture. Careful stepwise procedures were essential to treat the aneurysm and the tumor simultaneously.

Aged↗
PubMed1998

Central neurocytoma presenting with intratumoral hemorrhage 15 years after initial treatment by partial removal and irradiation.

A 50-year-old male presented with a central neurocytoma with intratumoral homorrhage. He had undergone partial removal of the tumor and postoperative radiation therapy 15 years previously. He was followed as an outpatient after the initial treatment, and there was no evidence of regrowth of the residual tumor. Removal of the hematoma and biopsy of the tumor were performed. Abnormally developed blood capillaries in the tumor may have undergone disturbances of circulation caused by irradiation which resulted in bleeding. Patients with partially resected central neurocytomas which have low proliferative potential may not require radiation therapy, due to the benign nature and the risk of delayed complications of irradiation including intratumoral hemorrhage.

Adult↗
PubMed1997

Functional morphology of the postcranium and locomotor behavior of Neosaimiri fieldsi, a Saimiri-like Middle Miocene platyrrhine.

A number of postcranial specimens of Neosaimiri fieldsi, a Middle Miocene platyrrhine, were discovered in 1988, 1989, and 1990 at La Venta, Colombia. Until recently only three postcranial specimens of this species had been discovered and the present material adds further information about this taxon's postcranial morphology. In overall skeletal dimensions and in postcranial features, Neosaimiri is most similar to Saimiri among extant medium-sized platyrrhines, but differs from Saimiri in having more rugose surface markings, a longer olecranon, a smaller anterior process of the distal tibia, an absence of a distal surface extension on the anterior tibial shaft, an absence of an anterior midtrochlear depression of the talus, and a shorter distal calcaneus relative to the calcaneal tuberosity. These differences suggest that Neosaimiri was relatively heavily built, possessed a more dominant forelimb in quadrupedal progression, and utilized a less stabilized upper ankle joint, and a shorter power arm for plantarflexion. Neosaimiri is interpreted as an arboreal quadruped with frequent leaping across arboreal gaps, as in extant Saimiri, with perhaps less frequent running and leaping than in Saimiri. As with the dentition, the postcranial specimens suggest the close relationship between Neosaimiri and extant Saimiri.

Animals↗
PubMed1997

[Practical localization of the central sulcus using a video display during surgery by cortical somatosensory evoked potentials and how to discern precentral P20 and central P25].

In patients with lesions around the central sulcus, cortical surface somatosensory evoked potentials (SEPs) have been applied for the purpose of localization of the central sulcus based on the polarity inversion of postcentral N20 to precentral P20 across the central sulcus. We have intraoperatively monitored SEPs to infer the location of the central sulcus in 16 cases since December 1988. Intraoperative localization of the central sulcus has been most useful in patients with frontal lobe gliomas in which the localization of the central sulcus enables the surgeon to extensively resect tumor without postoperative motor weakness. The localization of the central sulcus, however, might be misjudged by using the polarity inversion criterion alone, because central P25 following N20 and P20 complicates SEP waveforms. It is significant that P25, which is recorded also posterior to the central sulcus, is discerned from the precentral P20. In order to solve this matter, we regarded only the positivity in SEP waveforms having the identical peak latency to that of N20 as the precentral P20. Positive potentials having a later peak latency than that of N20 are the superposition of P20 and P25, and might also be recorded posterior to the central sulcus. For the observation of the polarity inversion of N20 to P20 across the central sulcus, a multi-channel SEP should be recorded using a sheet of silicone rubber embedded in a 16-electrode array consisting of a 4 by 4 grid. We projected the exposed cortical surface on the video display through the microscope apparatus and marked the locations of the recording electrodes on the video display. This enabled the location of the recording electrodes to correspond easily and precisely to the cortical surface. Our reliable and simple method of intraoperative localization of the central sulcus by cortical SEPs monitoring is presented in a practical case.

Adolescent↗
PubMed1996

Primary spinal leptomeningeal gliomatosis presenting visual disturbance as the initial symptom: case report.

We report a case of diffuse leptomeningeal gliomatosis which spread from the cervical to the sacral spine. A 60-year-old man was admitted with visual disturbance due to papilledema. Magnetic resonance imaging revealed holocord leptomeningeal gliomatosis without a definite intraparenchymal lesion, and the patient's neurological examination was unremarkable except for papilledema. Intracranial hypertension secondary to spinal tumor is well known but unusual, and the mechanism is still unclear. In our case, an elevated protein concentration of cerebrospinal fluid is suggested as the cause of intracranial hypertension.

Brain↗
PubMed1996

Locomotor differentiation and different skeletal morphologies in mangabeys (Lophocebus and Cercocebus).

The postcranial morphology of the arboreal white-cheeked mangabey (Lophocebus albigena) differs from that of partly terrestrial Cercocebus mangabeys (C. torquatus, C. galeritus). Its humerus has a reduced greater tuberosity, weak muscular insertions on the humeral shaft, less salient trochlear keels, a thinner diaphysis and less retroflexed medial epicondyle. The femur of L. albigena is characterized by a lowered greater trochanter, a thinner shaft, a flattened distal epiphysis and a wide and shallow patellar surface. The forelimb is short relative to other limb segments. L. albigena has attained these skeletal features by deducting the ancestral terrestrial adaptations, such as skeletal robusticity and joint restriction. Influence of phylogenetic inertia on the development of skeletal morphology are discussed.

Animals↗
PubMed1995

Postcranial skeleton of a macaque trained for bipedal standing and walking and implications for functional adaptation.

The postcranial skeleton of a Japanese macaque that had been trained for bipedalism over an 11-year period was studied. Considerable modifications in the hindlimb bones caused by bipedal postural and locomotor behaviour were observed. Changes occurred in joint morphology, articular dimensions and shape-dependent strength of long bones, reflecting the causal relationship between function and morphology. However, the conditions under which the modifications are developed are somewhat different from those in humans, as the monkey's bipedalism is distinct from that of humans. The modifications seem to result from a compromise between functional requirements and the genetically determined anatomy of the essentially quadrupedal monkey.

Animals↗
PubMed1993

Case of ring chromosome 7: the first report of neuropathological findings.

We report on a boy with ring chromosome 7 who had severe mental retardation, growth failure, microcephaly, cleft lip and palate, café-au-lait spots, nevus flammeus, and genital abnormalities, and died of pneumonia at age 20 months. On autopsy he had fusion of the anterior cerebral hemispheres, accompanied by agenesis of olfactory bulbs and tracts, closely resembling those found in semilobar holoprosencephaly. In addition, heterotopic Purkinje cell clusters in the cerebellar white matter, absence of pigmentation within the brainstem pigmented neurons, and severe hypomyelination in the whole brain were noted. The patient may represent the most severe manifestation of ring chromosome 7, and this is the first detailed neuropathological report on this subject.

Abnormalities, Multiple↗
PubMed1992

Monkey performance: the development of bipedalism in trained Japanese monkeys.

A series of studies collaborated by the Suo-sarumawashi (Japanese Monkey Performance) revealed the potential for bipedalism in Japanese monkey. The long-term training which aimed at stable upright posture introduced marked lumbar lordosis in monkeys. This feature is comparable to the humans' condition not only morphologically, but also functionally. The developed lordosis was retained even in normal pronograde posture of the monkeys. Bone remodeling in the postcranial skeleton also evidenced functional adaptations for stresses induced by sustained bipedalism. Postcrania of a trained monkey showed highly increased structural strength of bones and relatively large articular dimensions. Despite such adaptations, modifications of hindlimb bones were rather distinctive from humans' condition. This indicates a compromise between functional necessity and genetically determined anatomy. The hindlimb of Japanese monkey seemed to be more specialized for quadrupedal locomotion in many aspects compared to the vertebral column.

Animals↗
PubMed1989

[Cystic pineocytoma successfully treated with synchronized chemoradiotherapy. Case report].

A case of pineocytoma associated with intraventricular and meningeal metastasis is reported. The patient, a 25-year-old female, was admitted complaining of headache. Computed tomography revealed an irregular-shaped pineal lesion enhanced by contrast medium and accompanied by a cyst. An intraventricular cystic metastatic lesion and meningeal metastasis were also suggested. Biopsy of the pineal region proved the lesion to be a pineocytoma without neuronal or glial differentiation. Ventriculoperitoneal shunting was performed, and radiation therapy combined with chemotherapy (ACNU and vincristine) was administered. This treatment apparently destroyed both the primary and metastatic lesions, and the patient returned to her normal life. In 4 years of follow-up there has been no recurrence of the tumor. Pineocytoma with meningeal metastasis usually has a poor prognosis, but in this case combined radiation therapy and chemotherapy was curative. Although pineocytoma is rarely accompanied by a cyst, in cases of a pineal lesion coexistent with a cyst, a diagnosis of pineocytoma should be considered.

Adult↗
PubMed1988

[A case of alpha coma in acute brainstem dysfunction--consecutive electroencephalograms and evoked potentials].

A 31-year-old woman was admitted because of severe headache and dysarthria in December 1985. Neurological examination on admission revealed severe impairment of consciousness, anisocoria, absent light reflex on the right side, and evidence of left hemiparesis, but other brainstem reflexes were intact. A CT scan taken shortly after arrival demonstrated a large hematoma in the right temporal lobe and the right cerebellum. Breathing became irregular and intubation was needed. An emergency operation was performed. After the operation the patient remained comatose without any spontaneous respiration or brainstem reflexes. The next day she was still comatose without any spontaneous movement and other neurological finding remained unchanged. An initial EEG obtained at this time showed an 8- to 9-Hz alpha rhythm of about 15-40 microV with preponderance over the posterior and central regions. Some spontaneous variability was noted. The same day, investigations of brainstem auditory evoked potential (BAEP), visual evoked potential (VEP), and somatosensory evoked potential (SEP) were performed. BAEP showed only the first, second and third waves (I-III) bilaterally. VEP was able to elicit the primary response (II-III) without the secondary response. SEP could not be obtained from the early cortical response to left median nerve stimulation, but showed N14 bilaterally and small N20 upon right median nerve stimulation. On the second day of hospitalization, a repeated EEG showed generalized slowing with loss of alpha frequency rhythms and it proved impossible for SEP to elicit N20 bilaterally. At this time, BAEP showed bilateral I-IIIth waves and VEP still showed primary response.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Clinicophysiological study of multimodality evoked potentials and computed tomographic findings in persistent vegetative state].

The auditory brainstem response (ABR), short latency somatosensory evoked potential (SSEP) and visual evoked potential (VEP) of patients in the persistent vegetative state (PVS) are reported, and the correlations between the electrophysiological findings and the CT scan findings with the three clinical grades of the PVS (transitional, incomplete and complete vegetative syndromes) are discussed. Twenty two patients in a vegetative state caused by subarachnoid hemorrhage (3), hypertensive intracerebral hemorrhage (5), cerebral infarction (6), head injury (3), cerebral anoxia (4) and brain tumor (1). Each evoked response was evaluated for the presence or absence of abnormalities and assigned a grade ranked I to III. Briefly an evoked response was assigned a grade I, II, III if it satisfied the respective criteria of normal, moderately abnormal and severely abnormal or absent electrical activity. On the other hand CT scan findings in the PVS were evaluated for abnormal low density areas, ventricular dilatation and enlargement of the sulci and cisterns indicative of atrophy of the brain parenchyma. SSEP and VEP were better correlated with the clinical grade than ABR, and upper brainstem atrophy and abnormal low density area in CT scan findings were more valuable as an index to expresses the clinical features than ventricular dilatation. On the basis of these results, it is concluded that studies of ABR, SSEP and VEP associated with CT scan findings in the PVS could be a useful diagnostic aid to evaluate the lesions of these patients.

Adult↗