Progressive conus medullaris lesions are suggestive of intravascular large B-cell lymphoma.

BACKGROUND AND PURPOSE: Spinal cord lesions are observed in 40% of all central nervous system lesions in intravascular large B-cell lymphoma (IVLBCL). However, because IVLBCL is a very rare disease, its clinical features are not well defined, which may delay appropriate diagnosis and treatment, whilst the acute to subacute course of brain lesions in patients with IVLBCL is well established. Therefore, this study aimed to clarify the clinical features of spinal cord lesions in patients with IVLBCL. METHODS: The medical records of patients with IVLBCL admitted to our hospital between 2010 and 2020 were searched. The inclusion criteria were preceding neurological symptoms without non-neurological symptoms and pathologically confirmed IVLBCL in various organs. Clinical features of spinal cord involvement in patients with IVLBCL were assessed and distinguished from those of brain involvement. RESULTS: Sixteen consecutive patients with IVLBCL were divided into two groups: six patients with spinal involvement (spinal cord type) and 10 patients with brain involvement (brain type). In the spinal cord type, four patients had chronic progression and two had subacute progression. Acute progression (0% vs. 80.0%) and sudden onset (0% vs. 50.0%) occurred significantly less frequently in the spinal cord than in the brain. All spinal cord lesions involved the conus medullaris. CONCLUSIONS: Spinal cord involvement in IVLBCL has a predominantly chronic progressive course that is exclusive to brain involvement. Conus medullaris lesions are suggestive of IVLBCL and are useful for early and accurate diagnosis and treatment.

[65 years old man of chronic inflammatory demyelinating polyneuritis (CIDP) which presented radicular swelling and was able to confirm image progress before the onset].

The case is a 65 years old man. He noticed muscle weakness of lower limbs from 3 years ago. Dysesthesia was developed, He came in our hospital in X year. He was detected muscle weakness, sensory disturbance in distal lower limbs predominance and detected radicular significant swelling in spinal cord MRI and diagnosed it with chronic inflammatory demyelinating polyneuritis (CIDP). In the follow-up purpose of other diseases regularly, it was confirmed that nerve root was gradually swelling from around 7 years before the onset. The radicular swelling is one of the characteristics in CIDP, supports the diagnosis. This case was the valuable case that was able to chase image progress before the onset.

Activity concentration of natural radioactive nuclides in nonmetallic industrial raw materials in Japan.

Natural materials such as rock, ore, and clay, containing natural radioactive nuclides are widely used as industrial raw materials in Japan. If these are high concentrations, the workers who handle the material can be unknowingly exposed to radiation at a high level. In this study, about 80 nonmetallic natural materials frequently used as industrial raw materials in Japan were comprehensively collected from several industrial companies, and the activity concentrations of (238)U series, (232)Th series and (40)K in the materials was determined by ICP-MS (inductively-coupled plasma mass spectrometer) and gamma ray spectrum analyses. Effective doses to workers handling them were estimated by using methods for dose estimation given in the RP 122. We found the activity concentrations to be lower than the critical values defined by regulatory requirements as described in the IAEA Safety Guide. The maximum estimated effective dose to workers handling these materials was 0.16 mSv y(-1), which was lower than the reference level (1-20 mSv y(-1)) for existing situation given in the ICRP Publ.103.

Occupational exposure to natural radiation in zirconium refractory plants in Japan.

The authors measured the ambient dose rate and activity concentration of natural radionuclides in raw materials, products, and aerosols on worksites, as well as the (222)Rn and (220)Rn concentrations in an unshaped refractory, a shaped refractory, and an electrocast refractory plant processing zirconium ore in Japan. Estimations were made of the effective doses to plant workers. The activity concentration of the (238)U series in raw materials and products in the refractory plants was higher than the critical values (10 Bq g(-1) for (40)K and 1 Bq g(-1) for all other radionuclides of natural origin) specified in the International Atomic Energy Agency Safety Guide. The ambient dose rate in the raw material warehouse of the electrocast refractory plant was 0.75 µSv h(-1), which was the highest among all the worksites at all the refractory plants studied. The activity concentrations of aerosols in the product-output site of the unshaped refractory plant was 0.0015 Bq m for U and 0.00078 Bq m(-3) for (232)Th, which were the highest of all the worksites for all refractory plants. The indoor (222)Rn and (220)Rn concentrations in all worksites of all the refractory plants were almost the same levels as those in everyday indoor places in Japan. The maximum value of the effective dose to workers was 430 µSv y(-1), which was lower than the intervention exemption level (1,000 µSv y(-1)) specified in ICRP Publication 82.

Activity concentration of natural radionuclides and radon and thoron exhalation rates in rocks used as decorative wall coverings in Japan.

In Japan, many dwellings have decorative wall coverings made from granite, andesite, tuff, gabbro, and marble. However, information regarding activity concentrations and radon (Rn) and thoron (Rn) exhalation rates for such rocks is very scarce. Therefore, samples of the granite, andesite, tuff, and marble that are used as wall coverings in Japan were collected from mining companies, and their activity concentrations and Rn and Rn exhalation rates were measured. Dose estimations for inhabitants living in houses built with these materials were also carried out. The activity concentration of natural radionuclides in all the materials was lower than the critical values described by the International Atomic Energy Agency (IAEA) (10,000 Bq kg for K and 1,000 Bq kg for all other radionuclides of natural origin). The maximum values of Rn and Rn mass exhalation rates for the granite samples were 0.12 and 430 mBq kg s, and those for the area exhalation rates were 1.8 and 6300 mBq m s, respectively; these values are higher than those for other samples. The maximum value of effective doses to inhabitants was 0.68 mSv y, which is lower than the intervention exemption level (1 mSv y) given in the International Commission on Radiological Protection (ICRP) Publication 82.

[Case of unilateral alteration due to hypertensive encephalopathy].

We report a patient of a 20-year-old woman of Takayasu's arteritis and hypertensive encephalopathy. The symptoms started with headache and vomiting following status epilepticus. On arrival at the emergency room in our hospital, fever was apparent and cerebrospinal fluid examination revealed pleocytosis. After the admission, the patient presented with hypertension, decreased right brachial pulse and the difference between bilateral brachial arterial blood pressures on examination. There had been no history of arterial hypertension. The MR angiography revealed stenoses of the bilateral cervical, especially right cervical, right middle cerebral and left renal arteries. Brain MRI showed transient hyperintense lesions of the left fronto-parieto-occipital cortices and subcortical white matter in FLAIR and diffusion weighted images. These alterations suggested the presence of reversible vasogenic edema induced by hypertensive encephalopathy. We need to be aware of young patients with convulsion, especially young women, who has arterial hypertension as well as the difference with blood pressures between extremities.