Atypical bovine spongiform encephalopathy (BSE) has recently been identified in Europe, North America, and Japan. It is classified as H-type and L-type BSE according to the molecular mass of the disease-associated prion protein (PrP^Sc). To investigate the topographical distribution and deposition patterns of immunolabeled PrP^Sc, H-type BSE isolate was inoculated intracerebrally into cattle. H-type BSE was successfully transmitted to 3 calves, with incubation periods between 500 and 600 days. Moderate to severe spongiform changes were detected in the cerebral and cerebellar cortices, basal ganglia, thalamus, and brainstem. H-type BSE was characterized by the presence of PrP-immunopositive amyloid plaques in the white matter of the cerebrum, basal ganglia, and thalamus. Moreover, intraglial-type immunolabeled PrP^Sc was prominent throughout the brain. Stellate-type immunolabeled PrP^Sc was conspicuous in the gray matter of the cerebral cortex, basal ganglia, and thalamus, but not in the brainstem. In addition, PrP^Sc accumulation was detected in the peripheral nervous tissues, such as trigeminal ganglia, dorsal root ganglia, optic nerve, retina, and neurohypophysis. Cattle are susceptible to H-type BSE with a shorter incubation period, showing distinct and distinguishable phenotypes of PrP^Sc accumulation.

It has been assumed that the agent causing BSE in cattle is a uniform strain (classical BSE); however, different neuropathological and molecular phenotypes of BSE (atypical BSE) have been recently reported. We demonstrated the successful transmission of L‐type‐like atypical BSE detected in Japan (BSE/JP24 isolate) to cattle. Based on the incubation period, neuropathological hallmarks, and molecular properties of the abnormal host prion protein, the characteristics of BSE/JP24 prion were apparently distinguishable from the classical BSE prion and closely resemble those of bovine amyloidotic spongiform encephalopathy prion detected in Italy.

Background: Prions, infectious agents associated with transmissible spongiform encephalopathy, are primarily composed of the misfolded and pathogenic form (PrP^Sc) of the host-encoded prion protein. Because PrP^Sc retains infectivity after undergoing routine sterilizing processes, the cause of bovine spongiform encephalopathy (BSE) outbreaks are suspected to be feeding cattle meat and bone meals (MBMs) contaminated with the prion. To assess the validity of prion inactivation by heat treatment in yellow grease, which is produced in the industrial manufacturing process of MBMs, we pooled, homogenized, and heat treated the spinal cords of BSE-infected cows under various experimental conditions. Results: Prion inactivation was analyzed quantitatively in terms of the infectivity and PrP^Sc of the treated samples. Following treatment at 140°C for 1 h, infectivity was reduced to 1/35 of that of the untreated samples. Treatment at 180°C for 3 h was required to reduce infectivity. However, PrP^Sc was detected in all heat-treated samples by using the protein misfolding cyclic amplification (PMCA) technique, which amplifies PrP^Sc in vitro. Quantitative analysis of the inactivation efficiency of BSE PrP^Sc was possible with the introduction of the PMCA₅₀, which is the dilution ratio of 10% homogenate needed to yield 50% positivity for PrP^Sc in amplified samples. Conclusions: Log PMCA₅₀ exhibited a strong linear correlation with the transmission rate in the bioassay; infectivity was no longer detected when the log PMCA₅₀ of the inoculated sample was reduced to 1.75. The quantitative PMCA assay may be useful for safety evaluation for recycling and effective utilization of MBMs as an organic resource.

We have investigated the alignment of nematic liquid crystals (NLCs) using 50 nm ultrafine nanogrooves fabricated by electron-beam (EB) lithography and nanoimprint lithography. To improve the wettability of NLCs, silicon dioxide was sputtered onto the NLCs after nanogroove fabrication. The azimuthal and polar anchoring energies obtained were $9.4\times {10}^{-5}\text{J}/{\text{m}}^2$ and $3.6\times {10}^{-4}\text{J}/{\text{m}}^2$ , respectively. From the electro-optical characteristic of a twisted nematic (TN) liquid crystal (LC) cell, the contrast ratio of the TN cell was found to be 44:1, which is a relatively low value because of the misalignment of the EB exposure. However, a steeper and common threshold voltage was obtained for the TN LC cell.