A label-free, direct solid-phase fluorimetric analysis of ochratoxin A in agricultural products with monoclonal antibody-immobilized monolith.

We established a method for directly measuring mycotoxin ochratoxin A (OTA) in foods by solid-phase fluorescence of monolith-immobilized antibodies. The antibody was introduced onto only one side of an 8 mm-diameter, 3 mm-thick monolith via covalently immobilized protein G. 4 µg (2.7 × 10-11 mol) of antibody was immobilized per one monolith. A maximum of 10 µg (2.4 × 10-11 mol) OTA adsorbed to the activated side of each monolith. The amount of OTA adsorbed and the fluorescence intensity showed good linearity in the range of 0.5-3 ng OTA. Loading the sample solution onto the non-antibody side on the monolith blocked the hydrophobic fluorescent matrices from reaching the immobilized surface of the antibody. The proposed method was able to detect 1 ng OTA/g in solid samples with complex matrices. Mean recoveries obtained at spiked concentration of 3 ng g-1 OTA/g were 78-90% with relative standard deviations of <7.9%.

A case of α-synuclein gene duplication presenting with head-shaking movements.

BACKGROUND: PARK4 is a candidate locus for familial Parkinson's disease (PD), combined with multiplication of the α-synuclein gene (SNCA). The eventual phenotype is dependent on the copy number of SNCA. Mutations in leucine-rich repeat kinase 2 (LRRK2) are also causative of parkinsonism. This report describes a man who presented at our hospital complaining of a stagger after running and difficulty in handling the mouse of a personal computer, having suffered tremors since his twenties. Nine months after treatment and discharge, he developed titubation and began to drag his right foot. METHODS: We examined the patient's family pedigree for SNCA dosage, using quantitative polymerase chain reaction. We also screened this pedigree for mutations in parkin and LRRK2, using gene-sequencing techniques. RESULTS: We identified the proband, his sister, and his paternal uncle as carrying a duplication of SNCA. In addition, we found that the proband and his mother carried the G2385R variant of the LRRK2, a strong risk factor for PD in Asians and the rare V1450I variant, although only the proband showed symptoms of parkinsonism. No mutations were found in parkin. CONCLUSIONS: The combination of SNCA gene duplication and LRRK2 G2385R variant may explain the early onset of disease in this patient.

Gabapentin for Kleine-Levin syndrome.

We describe a 17-year-old girl with Kleine-Levin syndrome (KLS), in which gabapentin was effective for the prevention of attacks. (99)mTc-ECD SPECT revealed hyperperfusion of the thalamus and nucleus accumbens presenting in the symptomatic period, suggesting epilepsy-like neuronal discharge from these structures. Treatment for KLS has not been established, although lithium has been used in limited cases with insignificant efficacy. Here, we report a case of recurrent hypersomnia in which gabapentin was effective for the prevention of attacks. We speculate that the recurrent hypersomnia and behaviour disturbance are related to epilepsy-like neuronal discharge from the thalamus due to dysfunction in GABAnergic receptors.

[A case of subacute necrotizing lymphadenitis with recurrent aseptic meningitis 11 years after the first episode].

We report a 29-year-old man with subacute necrotizing lymphadenitis (SNL) associated with recurrent aseptic meningitis following an 11-year remission period. In both episodes, headache and fever were followed by lymphadenopathy, with increased serum IgE level. Although pleocytosis in cerebrospinal fluid was confirmed at admission in the first episode, it appeared at one week after admission in the second episode. Administration of glucocorticoid was effective for treating meningitis. The present case suggests a pathomechanism for SNL that involves both an immunological background and an acute viral infection as triggers of exacerbation of aseptic meningitis.

Functional imaging of the human lateral geniculate nucleus and pulvinar.

In the human brain, little is known about the functional anatomy and response properties of subcortical nuclei containing visual maps such as the lateral geniculate nucleus (LGN) and the pulvinar. Using functional magnetic resonance imaging (fMRI) at 3 tesla (T), collective responses of neural populations in the LGN were measured as a function of stimulus contrast and flicker reversal rate and compared with those obtained in visual cortex. Flickering checkerboard stimuli presented in alternation to the right and left hemifields reliably activated the LGN. The peak of the LGN activation was found to be on average within +/-2 mm of the anatomical location of the LGN, as identified on high-resolution structural images. In all visual areas except the middle temporal (MT), fMRI responses increased monotonically with stimulus contrast. In the LGN, the dynamic response range of the contrast function was larger and contrast gain was lower than in the cortex. Contrast sensitivity was lowest in the LGN and V1 and increased gradually in extrastriate cortex. In area MT, responses were saturated at 4% contrast. Response modulation by changes in flicker rate was similar in the LGN and V1 and occurred mainly in the frequency range between 0.5 and 7.5 Hz; in contrast, in extrastriate areas V4, V3A, and MT, responses were modulated mainly in the frequency range between 7.5 and 20 Hz. In the human pulvinar, no activations were obtained with the experimental designs used to probe response properties of the LGN. However, regions in the mediodorsal right and left pulvinar were found to be consistently activated by bilaterally presented flickering checkerboard stimuli, when subjects attended to the stimuli. Taken together, our results demonstrate that fMRI at 3 T can be used effectively to study thalamocortical circuits in the human brain.

Attention modulates responses in the human lateral geniculate nucleus.

Attentional mechanisms are important for selecting relevant information and filtering out irrelevant information from cluttered visual scenes. Selective attention has previously been shown to affect neural activity in both extrastriate and striate visual cortex. Here, evidence from functional brain imaging shows that attentional response modulation is not confined to cortical processing, but can occur as early as the thalamic level. We found that attention modulated neural activity in the human lateral geniculate nucleus (LGN) in several ways: it enhanced neural responses to attended stimuli, attenuated responses to ignored stimuli and increased baseline activity in the absence of visual stimulation. The LGN, traditionally viewed as the gateway to visual cortex, may also serve as a 'gatekeeper' in controlling attentional response gain.