Generators of visual evoked potentials for faces and eyes in the human brain as determined by dipole localization

Human visual evoked potentials were recorded during presentation of photos of human and animal faces and various face features. Negative waves with approximate peak latencies of 165 msec (N170) were bilaterally recorded from the occipito-temporal regions. Mean peak latencies of the N170 were shorter for faces than eyes only. Analyses of amplitudes of evoked potentials indicated that the N170 elicited by faces reflected activity of a specific neural system which was insensitive to detailed differences among individual faces regardless of species, and consequently suggest that this system might function to detect existence of faces in general. On the other hand, the mean amplitude of the N170 elicited by human eyes was significantly larger than those by animal eyes. These differences in response latencies and amplitudes of the N170 suggest existence of at least 2 different visual evoked potentials with similar latencies (i.e., N170) which are sensitive to faces in general and human eyes, respectively. Dipole source localization analysis indicated that dipoles for the N170 elicited by eyes were located in the posterior inferior temporal gyrus, and those for faces, located initially in the same region, but moved toward the fusiform and lingual gyri at the late phase of the N170. The results indicated that information processing of faces and eyes separated at least as early as the latency of the N170 at the posterior inferior temporal gyrus as well as the fusiform and lingual gyri, and might provide neurophysiological and anatomical bases to an initial structural encoding stage of human faces.     

Platelet-activating factor in Japanese cedar pollinosis

Japanese cedar pollinosis is a typical allergic disease and has recently become a big social problem. Many population are suffering from this disease every year from the end of February to the beginning of April. In this study, we planned to examine the role of platelet-activating factor (PAF) in this disease, because PAF has been known to be one of the potent chemical mediators in allergic and inflammatory reactions and many evidences indicate that PAF is deeply involved in the pathogenesis of bronchial asthma, a typical allergic disease. We measured the concentrations of the PAF derivative (lyso-PAF) in serum from patients with cedar pollinosis during the pollen season. The level of lyso-PAF in serum from untreated patients with cedar pollinosis (87.8 +/- 8.7 unit.) was significantly higher than that in healthy control (54.9 +/- 7.7 unit.). We also tested the effect of an anti-allergic drug on the level of serum lyso-PAF of cedar pollinosis. Eighteen pairs of serum samples from patients with cedar pollinosis were employed in this study. Lyso-PAF levels after two weeks' therapy with ketotifen (2 mg/day), an anti-allergic drug, decreased the levels significantly (from 82.6 unit to 41.3 unit). These results suggest that PAF could play some important role in cedar pollinosis and that the clinical effect of anti-allergic drug could be partially due to the anti-PAF action.     

Mechanisms of blood coagulation induced by latex particles and the roles of blood cells

Latex particles with highly negative or positive charges shortened the clotting time of whole blood and platelet-rich plasma and activated platelet factor 3. Platelet-poor plasma was clotted by the particles with a highly negative charge, but not by those with a positive charge, except hydrophobic particles. Blood coagulation by positively-charged particles was attributed to platelet activation. An enhancement of blood coagulation was also observed in the presence of erythrocytes, leucocytes, their cell membranes or negatively charged phospholipids, and phosphatidylserine instead of platelets. Hydrophilic and low-charged particles suppressed blood coagulation.     

A case of food-dependent-exercise induced anaphylaxis possibly induced by shellfish (Sulculus Supertexta and Turbo Cornutus)

A 17 years old girl experienced an anaphylactic reaction of urticaria, dyspnea, syncope and hypotension while riding a bicycle 55 minutes after eating shellfish Lapas shellfish which was a-like Sulculus Supertexta (SS). She recovered within several hours after the emergency treatment. Another attack occurred 3 months later while she was running with a dog 30 minutes after eating shellfish (Turbo Cornutus; TC). RAST scores were 4 for Lapas and 2 for TC. RAST inhibition test by ELISA showed a high crose-reaction between keyhole limpet hemocyanin (KLH) and Lapas, and between KLH and TC, while the cross reaction between Lapas and TC was low. Gel chromatography with sephacryl G-200 revealed that both Lapas and TC had several allergens with different molecules which were detected by ELISA. Exercise challenge produced an immediate fall of FEV1 and a significant increase in plasma histamine levels for 45 minutes.     

Platelet-activating factor in late asthmatic response

The role of platelet-activating factor (PAF) in the late asthmatic responses was studied. The concentrations of lyso-form of PAF in plasma were measured at 0 and 20 min, and 6 and 24 h after the antigen inhalation challenge among patients with bronchial asthma. PAF activities were measured by their aggregating ability of washed rabbit platelets after acetylation of lyso-PAF into the biological active form of PAF, when there were no detectable amounts of PAF in plasma. The concentrations of lyso-PAF were found to be significantly increased in patients with the late asthmatic response compared with patients with the single immediate response at 6 h after the antigen challenge. In contrast, lyso-PAF levels were not significantly different at 20 min after the antigen challenge between these two groups. PAF inactivator activity in plasma increased when there was a decrease in the lyso-PAF level. These results suggest that PAF may participate in the late asthmatic response and may provide a new insight into the pathogenesis and the treatment of bronchial asthma.     

ROUTINE LOW AND HIGH RESOLUTION TYPING OF THE HLA-DRB GENE USING THE PCR-MPH (MICROTITRE PLATE HYBRIDIZATION) METHOD

We describe HLA-DRB1 typing using polymerase chain reaction-based microtitre plate hybridization (PCR-MPH), which can process large numbers of samples. MPH typing is similar to an enzyme-linked immunosorbent assay (ELISA), in which a tandemly ligated sequence-specific oligonucleotide is immobilized on microtitre wells. The typing procedure consisted of two steps. In the first, PCR-MPH with 16 probes was performed to determine the specificities of the serological levels (DR1, DR2, DR3, DR4, DR11, DR12, DR13, DR14, DR7, DR8, DR9 and DR10) after generic amplification (‘low resolution typing’). In the second step, DR1, DR2, DR4, DR 12/8 and DR3/11/13/14 were group-specifically amplified based on the results of the first PCR-MPH, and microtitre plate hybridization proceeded in a similar manner to the first step (‘high resolution typing’). Low resolution typing was completed within 2 h after generic amplification, and the results of high resolution typing were obtained in another 3.5 h after amplification. The allelic types classified using PCR-MPH were completely concordant with those obtained by PCR- single-strand conformation polymorphism or PCR-restriction fragment length polymorphism.     

Monoclonality of infiltrating plasma cells in primary pulmonary nodular amyloidosis: detection with polymerase chain reaction

AIMS: To investigate the relation between localised amyloidosis and immunocytic dyscrasia. METHODS: Open lung biopsy specimens from a 72 year old man with multiple nodules in the right middle and lower lung were stained with haematoxylin-eosin, Congo red, and antibodies against IgG, IgA, IgM, and kappa and lambda light chains. Semi-nested PCR amplification for the immunoglobulin heavy chain (IgH) gene was performed using consensus primers for the VDJ region of the IgH gene, FR3A, LJH, and VLJH. RESULTS: The biopsy specimens contained eosinophilic amorphous material stained with Congro red and anti-kappa light chain, and surrounded by inflammatory cells intermingled with plasma cells. Plasma cells in the adjacent amorphous material showed cytoplasmic staining with anti-kappa. Polymerase chain reaction revealed a discrete amplified band of apparently uniform size with background smear. CONCLUSIONS: Primary AL type localised amyloidosis involves local accumulation of monoclonal plasma cells and their secreted products, as in nodular cutaneous amyloidosis. Localised AL type nodular amyloidosis is a separate entity in amyloidosis.     

Application of hepatitis B core particles produced by human primary hepatocellular carcinoma (PLC/342) propagated in nude mice to the determination of anti-HBc by passive hemagglutination

Human primary hepatocellular carcinoma (PLC/342), carried by nude mice, produces hepatitis B core particles as well as hepatitis B surface antigen particles. Core particles purified form PLC/342 tumors displayed epitopes of hepatitis B core antigen (HBcAg) but not epitopes of hepatitis B e antigen (HBeAg) on their surface, unlike core particles prepared from Dane particles, derived from plasma of asymptomatic carriers, that expressed epitopes of both HBcAg and HBeAg. Core particles obtained from PLC/342 tumors were applied to the determination of antibody to HBcAg (anti-HBc) by passive hemagglutination. The assay detected anti-HBc not only in individuals with persistent infection with hepatitis B virus and in those who had recovered from transient infection, but also in patients with acute type B hepatitis, indicating that it can detect anti-HBc of either IgG or IgM class. A liberal availability of core particles from tumors carried by nude mice, taken together with an easy applicability of the method, would make the passive hemagglutination for anti-HBc a valuable tool in clinical and epidemiological studies, especially in places where sophisticated methods are not feasible.