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A microbeam analysis system has been developed at Tohoku University for biological applications. Spatial resolution of less than 1 μm has been achieved with a beam current of ~40 pA. In microbeam analysis of biological specimens, simultaneous measurement of structural and elemental properties is very important. Our system is applicable to simultaneous in-air/vacuum PIXE, RBS and STIM analyses. Typical results of biological application are shown.

We developed a novel technique to obtain 3D-imaging of elemental distribution based on multi-angle RBS measurement and micro-beam scanning. Since cross-sections of RBS are too small to obtain 3D-imaging, it is necessary to measure scattered particles with large solid angle detectors. Hence, the RBS profiles from each scattering angle are superposed and a true depth profile cannot be obtained. Recently, a large solid angle X-ray detector array consisting of 45 detector elements was installed at the TIARA facility of Japan Energy Research Institute. Each detector element measures X-rays as well as scattered particles. For this utilization, we introduced a technique to superpose RBS profiles and applied it to the surface analysis of an ant’s head.

We developed mini step samplers with low manufacturing and running costs for application in multi-site air-pollution monitoring. The miniaturization of the sampler was achieved by reducing the suction nozzle size. We tested the samplers with suction nozzle diameters of 2 and 4 mm through simultaneous exposure in the same site. Elemental concentrations of aerosol collected by these samplers were consistent within ±20% during comparison and the sample uniformity did not differ significantly. Sampling with small suction nozzle did not adversely affect aerosol collection. Aerosol samples were collected simultaneously at two sites in our laboratory and in the hall outside for 3 days and analyzed subsequently by PIXE. The time variation of elemental concentrations was high during daytime and low at night time and also during the weekend. Elemental concentrations in the hall were always higher than those in the laboratory. In our laboratory, we change shoes at the entrance and therefore, elemental concentrations inside the lab are lower than in the hall. In a second field experiment, we carried out simultaneous multi-site aerosol sampling during two periods in correlation with meteorological data (wind direction and velocity). It was observed that elemental concentrations of some soil origin elements changed periodically. On the other hand, the concentration of Cu and Zn showed irregular concentration spikes whose pattern showed a variation with the sites. Analysis using the data of wind directions showed that Cu had been transported to the sites from northeasterly direction and that the concentration of Zn was influenced by two big factories nearby. In conclusion, it has been demonstrated that the multi-site sampling system combined with meteorological data is well suited to identify sources of pollution.

The relationship of the Trail Making Test (TMT) to the frontal lobes was tested by comparing patients with damage to the frontal and nonfrontal regions to control participants. Although the analysis of time measurements, both raw and transformed, showed notable slowing of frontal groups, error analysis proved to be a more useful method of categorizing performance. Analysis of errors on Part B indicated that all patients who made more than 1 error had frontal lesions. Dividing the frontal damaged patients into subgroups on the basis of the number of errors yielded specificity of brain-behavior relations within the frontal lobes. Patients with damage in dorsolateral frontal areas were most impaired. Those with inferior medial damage to the frontal lobes were not significantly affected in TMT Part B performance.

Seventy-four patients with focal brain lesions were compared to a neurologically normal control group on tasks of letter-based and category-based list generation. When patients were divided only by right frontal, left frontal, or nonfrontal lesion sites, the pattern of fluency impairments confirmed prior claims. When more precise lesion sites within the frontal lobes were compared between groups classified based on their fluency performance, much more specific brain-behavior relations were uncovered. Damage to the right dorsolateral cortical or connecting striatal regions, the right posterior area, or the medial inferior frontal lobe of either hemisphere did not significantly affect letter-based fluency performance. Superior medial frontal damage, right or left, resulted in moderate impairment. Patients with left dorsolateral and/or striatal lesions were most impaired. Left parietal damage led to performance relatively equivalent to the superior medial and left dorsolateral groups. The same lesion sites produced impairments in category based fluency, but so did lesions of right dorsolateral and inferior medial regions. Task analysis and correlations with other measures revealed that different cognitive processes related to different brain regions underlie performance on verbal fluency tests.

A 31-year-old man presenting with a cerebellopontine angle syndrome underwent subtotal resection of a gangliocytoma of the left middle cerebellar peduncle. The tumor was positive for 68-kD neurofilament protein and vasoactive intestinal peptide. No glial cells were identified on immunohistochemical or ultrastructural examination. Electron microscopic study of neoplastic ganglionic cells revealed the presence of dense core vesicles, synaptic junctions, Hirano bodies, and marked dystrophic changes in the neuritic processes. The nosology of this lesion is discussed. Similarities between the morphological changes shown by mature neoplastic ganglion cells and comparable structural alterations seen in the physiological senescence of nonneoplastic neurons are stressed. (Neurosurgery 22:576-581, 1988)

A novel presentation of intravascular papillary endothelial hyperplasia within a cerebral cavernous angioma in an adult is described. The pathogenesis of the lesion and its histological differentiation from malignant angiosarcoma are stressed.

The criteria for hospital admission of children who have suffered a minor head injury are highly subjective. Often the presence of post-traumatic emesis becomes an influential factor, but the mechanisms that trigger emesis following minor head injuries are not known. From a prospective study of 96 consecutive children with their first mild head injury (GCS 13-15) and a retrospective study of 29 consecutive more seriously injured children (GCS 8-12), we conclude that post-traumatic emesis is more common: (1) following minor head injuries than following more severe head injuries (P less than 0.05); (2) in children over 2 years old; (P less than 0.001); (3) in children injured within an hour of a meal or snack (p less than 0.001). The presence of a skull fracture or the site of the impact does not influence the incidence or duration of post-traumatic emesis. Retching and vomiting generally subside within 3 h in children injured within an hour of a meal or snack. When vomiting appears in children injured more than an hour after a meal or a snack, it may be quite protracted (mean = 7.5 h). Children over 2 years of age with post-traumatic emesis who are neurologically stable following a mild head injury that occurred within an hour of a meal or snack can be expected to improve quickly. Their counterparts injured more than an hour after a meal or snack are likely to remain distressed much longer and are best admitted to hospital.

The peroxidase anti-peroxidase technique was used for localization of glial fibrillary acidic protein (GFAP) and vimentin (VM) in 19 ependymal tumors in order to determine if a unique pattern of intermediate filament (IF) expression could be demonstrated. Cytokeratin (CK) immunoreactivity was examined in a subgroup of 7 tumors with papillary pattern. Nineteen non-ependymal neuroectodermal tumors were used as controls. Ependymomas, subependymomas and astrocytomas were positive for both IF. Oligodendrogliomas, oligodendroglial portions of mixed gliomas and the majority of medulloblastomas were negative for GFAP and VM. Areas of poor differentiation in all tumors demonstrated little expression of any IF. A composite ependymoma/choroid plexus papilloma showed the presence of GFAP, VM and CK in the papillomatous portion only. Four papillary ependymomas were negative for CK. This study emphasizes the parallel distribution of GFAP and VM in well differentiated ependymomas and other glial tumors and casts doubt upon the concept of VM as a marker for de-differentiation in neuroectodermal neoplasia.

We describe four patients and review prior reports to clarify the clinical, radiographic, and pathologic findings of intracranial vertebral artery (VA) dissection. A 43-year-old man and a 33-year-old woman had chronic bilateral VA dissecting aneurysms. The man had multiple episodes of subarachnoid hemorrhage (SAH) and necropsy showed multiple dissections and defects in the internal elastica. The woman had many brainstem TIAs and strokes during 3 years. Two other patients had SAH and unilateral dissections. Intracranial VA dissection causes four overlapping syndromes: (1) brainstem infarcts are usually due to subintimal dissection extending into the basilar artery, affect younger patients, and often are single fatal events; (2) SAH is due to subadventitial or transmural dissection; (3) aneurysms cause mass effect on the brainstem and lower cranial nerves; and (4) chronic dissections due to connective tissue defects cause extensive bilateral aneurysms and repeated TIAs, small strokes, and SAH.