The effect of stimulus probability on the somatosensory mismatch field

We investigated the effect of deviant stimulus probability on the somatosensory magnetic mismatch negativity (MMNm) using an electrical two-point stimulation. First, we determined the discrimination threshold (DT) of the two-point distance. We applied standard stimuli at a distance that subjects felt as one point and deviant stimuli at a distance that subjects definitely felt as two points. We used three deviant stimulus probabilities, 10, 30, and 50%. The components peaking around 30–70 ms (first component) and 150–250 ms (fourth component) following deviant stimuli were significantly larger than those following standard stimuli in 10% condition, but not in 30 or 50% condition. The equivalent current dipole (ECD) was located in the contralateral primary somatosensory cortex (cSI) for the first component, and in the cSI and in the contralateral secondary somatosensory cortex (cSII) for the fourth component. The peak amplitude of the MMNm decreased as the probability of the deviant stimulus increased. The Somatosensory MMNm was affected by deviant stimulus probability similar to an auditory mismatch negativity (MMN).     

Non-A, non-B hepatitis related AN6520 Ag is a normal cellular protein mainly expressed in liver. II

Detection of AN6520 Ag/Ab in human sera had indicated a close association with non-A, non-B hepatitis (NANBH). In this study, we investigated the immunochemical nature of AN6520 Ag and measured the amounts in various human and chimpanzee organs in order to clarify the association with NANBH. AN6520 Ag was found to be composed of polypeptide(s) with an apparent molecular weight of 45,000 daltons (45 kD), which are noncovalently linked together. Human antibodies in convalescent sera from NANBH patients as well as monoclonal antibodies were found to recognize only the high-order structure of the antigen, whereas rabbit antibody recognized both the high-order structure and the reduced form of 45 kD polypeptide(s). AN6520 Ag could be detected in most of the livers tested including those without any liver damage and fetal livers; their amounts varied considerably from each other. The antigen could be detected also in organs other than liver, but in contrast to liver, the amounts were small and did not vary as much between individuals. From the data of immunoblotting using rabbit antibody, our observed variation of antigen content in liver was considered to be due to the difference in expression of 45 kD polypeptide(s). Although no specific relationship was found between the amount of the antigen in liver and NANBH, the antigen was found to increase several times in livers of chimpanzees after the inoculation of NANBH virus. These data suggest that AN6520 Ag is a normal cellular protein existing mainly in liver and that its quantity may vary under some conditions such as NANBH.     

Visualization of nasopharyngeal carcinoma with Tl-201 chloride and a three-head rotating gamma camera SPECT system

Tl-201 SPECT was performed on 12 patients with Nasopharyngeal carcinoma (NPC) by means of a three-head rotating gamma camera to evaluate whether or not Tl-201 SPECT was useful and reliable for assessing the tumor viability of NPC. Tl-201 clearly accumulated in the tumor in 3 patients before radiation treatment and increased Tl-201 uptake by the lesion ceased after the treatment. Three of 9 patients who were followed up after radiotherapy developed apparent local recurrence and Tl-201 SPECT clearly visualized these recurrent lesions. Tl-201 SPECT was very useful for assessing the tumor response to irradiation and for detecting local recurrent tumor. A High resolution SPECT system employing Tl-201 chloride is a new reliable and accurate diagnostic tool for the assessment of NPC.     

Usefulness of bone SPECT of the cervical spine : With special reference to separate visualization of the trachea and thyroid cartilage

We applied bone SPECT for the examination of the cervical spine. A three-head rotating gamma camera SPECT system was employed for this study. The SPECT image disclosed 42.7 % of abnormal accumulations in the skeleton not seen with planar imagings. SPECT could separately visualize the trachea and thyroid cartilage and also provided interpretation of abnormality in the anterior part of the vertebral body being difficult with planar imagings only. The trachea cartilage was seen in 55.4% and the thyroid cartilage was seen in 47.3% of patients with anterior neck density in planar imagings. SPECT clarified that marked cervical curvature and diffuse high uptake by the skeleton might cause high intensity of the anterior neck in planar imagings in the case of non-pathological change. We concluded that bone SPECT is a useful diagnostic tool in detecting occult lesion in the skeleton and to rule out extraskeletal accumulations in examination of the cervical spine.     

Effects of iomeprol,a new nonionic contrast medium,vis a vis iopamidol and nitroglycerin,on coronary diameter and blood flow in chronically instrumented dogs

The effects of an intracoronary administration of iomeprol, a new nonionic tri-iodinated water-soluble contrast medium, on coronary circulation were compared to those of iopamidol and those of nitroglycerin in 6 chronically instrumented conscious dogs. A pair of 10 MHz piezoelectric crystals and an electromagnetic flow probe were placed on the left circumflex coronary artery (LCCA) to measure the epicardial coronary diameter (CD) and coronary blood flow (CBF). Polyethylene tubing for drug administration was inserted into the LCCA proximal to the sonomicrometers. Iomeprol at the dose of 1 ml and 3 ml/min for 1 min significantly increased CD by 0.6±0.1% and 1.4±0.3%, respectively and CBF by 44.5±9% and 70±10%, respectively. Iopamidol at the same rates also significantly increased CD by 0.8±0.1% and 1.5±0.3% and CBF by 50±11% and 82±14%, respectively. There was no statistically significant difference between iomeprol-and iopamidol-induced increases in CD and CBF. However, the duration of the increase in CD was significantly shorter (p<0.05) after iomeprol than after iopamidol. Nitroglycerin (10 μg/kg) significantly increased CD by 4.5±1% and CBF by 105±10%. The increases in CD and CBF in response to iopamidol and iomeprol were significantly smaller (p<0.01) than to nitroglycerin. We conclude that vasodilating effects of iomeprol and iopamidol on the large epicardial coronary artery and coronary blood flow are comparable in conscious dogs and significantly lower than after nitroglycerin in the doses used by us. This study was supported by a grant from the EI-ZA1 Pharmaceutical Co., Tokyo, Japan.     

Infectious Complications in Childhood Leukemia

Since children with acute leukemia have prolonged periods of severe neutropenia due to the disease itself or its intensive chemotherapy, they often develop life-threatening infectious complications. A protected environment and prophylactic antibiotics for patients with severe neutropenia have been shown to decrease the incidence of infectious morbidity. In spite of the high mortality rate of infections, on the other hand, their diagnosis is not well established because the percentage of microbiological detectability by blood culture is low. The differentiation of infections may be possible by using some supplementary measures and particular laboratory parameters. Febrile neutropenic patients with leukemia should promptly receive empiric treatment with combinations of two or three broad-spectrum antibiotics that are bactericidal and synergistic toward the presumed pathogens, or with antifungal drugs if patients are resistant to antibiotics, as well as supportive measures such as granulocyte transfusion, intravenous gamma-globulin and granulocyte colony-stimulating factor.     

Antimicrobial Chemotherapy for Children with Malignancy

Infection is the major complication occurring in children with cancer and is often fatal. Since the clinical manifestations of infection are slight, except for fever, a definitive diagnosis is difficult in the early phase of infection, but using laboratory parameters, the differentiation of bacterial infections may be possible to some extent. The infection cannot be treated only by antimicrobial chemotherapy, but supportive measures such as neutrophil transfusion, and other biological medications should be given in consideration of the deficiency of the immune defense mechanisms of the patient. Anticancer treatment is also needed, along with antimicrobial treatment. The prophylactic use of antimicrobial drugs is still controversial but it is effective, depending on the type of infection for which it is used, and on the status of the defective defense mechanism in the patient who is on cancer chemotherapy.     

The significance of pulmonary surfactant deficiency during extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is gaining widespread acceptance as a therapy for newborns with severe respiratory distress. However, in some cases with pulmonary opacification or air-bronchograms on chest radiograph during ECMO, pulmonary function does not readily improve despite successful ECMO practice. We applied artificial pulmonary surfactant in two such cases. The effect was remarkable, and successful weaning from ECMO could be achieved. It appears likely that alveolar collapse due to deficient pulmonary surfactant is one cause of abnormal pulmonary shadows on chest radiographs and delayed resolution of pulmonary function during ECMO.