Babesia canis infection in canine-red blood cell-substituted SCID mice

We have developed a mouse model for Babesia canis infection using severe combined immunodeficiency (SCID) mice whose circulating red blood cells had been substituted with canine red blood cells. Substitution of red blood cells in SCID mice was achieved by repetitive transfusions of canine red blood cells, together with administration of an antimouse red blood cell monoclonal antibody. Following inoculation of canine-red blood cell-SCID mice with B. canis, parasites proliferated in the canine red blood cells that had been transfused into the SCID mice, resulting in much higher parasitaemia than that observed in dogs. In an attempt to demonstrate the utility of this mouse model, three antiprotozoal drugs, diminazene diaceturate, clindamycin and oxytetracycline, were examined for their efficacy to inhibit the growth of B. canis in canine-red blood cell-SCID mice. The mouse model clearly showed that diminazene diaceturate and oxytetracycline were capable of eliminating B. canis from the canine-red blood cell-SCID mice, whereas clindamycin exhibited only a static effect as parasitaemia relapsed upon cessation of drug administration.     

Symmetricity of the solution of semidefinite programming

Symmetricity of an optimal solution of Semi-Definite Programming (SDP) is discussed based on the symmetry property of the central path that is traced by a primal-dual interior-point method. A symmetric SDP is defined by operators for rearranging elements of matrices and vectors, and the solution on the central path is proved to be symmetric. Therefore, it is theoretically guaranteed that a symmetric optimal solution is always obtained by using a primal-dual interior-point method even if there exist other asymmetric optimal solutions. The optimization problem of symmetric trusses under eigenvalue constraints is shown to be formulated as a symmetric SDP. Numerical experiments illustrate convergence to strictly symmetric optimal solutions.     

DYNAMIC KINETICS OF THE COMMON INTERMEDIATES FORMED IN CO AND CO2 HYDROGENATIONS ON Rh/MgO

Stable intermediates are formed during both CO and CO₂ hydrogenations on Rh/MgO at 190-220^°C. The intermediates consist of at least four species, each of which is consecutively and irreversibly converted at a similar rate, forming the final product of CH₄ by reaction with H₂     

Statistical methods for detecting activated regions in functional MRI of the brain

Two statistical tests for detecting activated pixels in functional MRI (fMRI) data are presented. The first test (t-test) is the optimal solution to the problem of detecting a known activation signal in Gaussian white noise. The results of this test are shown to be equivalent to the cross-correlation method that is widely used for activation detection in fMRI. The second test (F test) is the optimal solution when the measured data are modeled to consist of an unknown activation signal that lies in a known lower dimensional subspace of the measurement space with added Gaussian white noise. A model for the signal subspace based on a truncated trigonometric Fourier series is proposed for periodic activation-baseline imaging paradigms. The advantage of the second method is that it does not assume any information about the shape or delay of the activation signal, except that it is periodic with the same period as the activation-baseline pattern. The two models are applied to experimental echo-planar fMRI data sets and the results are compared.     

Sporadic activation of Epstein-Barr virus in thyroid lymphoma

The causal role of Epstein-Barr virus (EBV) in the development of B-cell lymphoma, especially in immunocompromised individuals, has been suggested. The purpose of the present study was to evaluate an association of EBV with thyroid lymphoma (TL) and chronic lymphocytic thyroiditis (CLTH) which is known to play an important role in the development of TL. Thirty cases with TL and 28 with CLTH were studied for presence or absence of EBV genome in the lesions using the polymerase chain reaction (PCR) and the in situ hybridization method. EBV genomes were detected by PCR in one and two cases with CLTH and TL, respectively. Subtyping of EBV genome was possible in one TL case showing B-type in EBNA-2 coding region. In situ hybridization revealed positive signals in the nucleus of lymphoma cells, which also expressed latent membrane protein-1. The present findings indicate that activation of EBV in TL is not common.     

Cryogenic neutron detector by InSb semiconductor detector with high-density helium-3 gas converter

The neutron-detection characteristics of a cryogenic neutron detector comprising an InSb semiconductor detector and a helium-3 gas converter were evaluated at a gas pressure up to 12.4 atm at 4.2 K. The detector successfully detected stable neutrons under these conditions, where the density of the helium-3 gas is a few-hundred times higher than that at room temperature. It was found that the neutron detection efficiency was correlated with the gas pressure—even in a backward-detection configuration—in low-temperature, high-pressure helium-3.     

A case report of resected primary duodenal carcinoma associated with early gastric cancer and cumulative results at 21 institutions in Japan

A case of primary duodenal carcinoma simultaneously associated with an early gastric cancer is reported. A 72-year-old woman complaining of appetite loss and nausea was admitted in June 1988. Endoscopic examination showed an ulcerative lesion in the angle of the stomach and a Borrmann type 2 tumor in the bulb of the duodenum. Both lesions were revealed to be adenocarcinomas by histological examination of obtained biopsy specimens. Synchronous carcinoma was diagnosed and pancreatoduodenectomy and lymph node dissection were performed. The primary tumor of the duodenum was histologically a moderately differentiated adenocarcinoma, and the gastric cancer was a tumor limited to the mucosa. Metastasis was recognized in a regional lymph node (No. 14A). There has been no recurrence during the 4-year postoperative follow-up period. This result suggests that pancreatoduodenectomy with systematic regional lymph node dissection can greatly contribute to prolonging the survival of patients with advanced duodenal cancer. This case is very rare, in that curative operation was performed for a primary duodenal carcinoma simultaneously associated with an early gastric cancer.