For the clinical diagnosis of MM2-type sporadic Creutzfeldt-Jakob disease, cortical hyperintensity signals on diffusion-weighted MRI are useful for the cortical form and thalamic hypoperfusion or hypometabolism on cerebral blood flow SPECT or [18F]2-fluoro-2-deoxy-d-glucose PET for the thalamic form.

In order to clarify the clinical and genetic features of SCA6, we retrospectively analyzed 140 patients. We observed an inverse correlation between the age of onset and the length of the expanded allele, and also between the age of onset and the sum of CAG repeats in the normal and the expanded alleles. The ages of onset of four homozygous patients correlated better with the sum of CAG repeats in both alleles rather than with the expanded allele calculated from heterozygous SCA6 subjects. Clinically, unsteadiness of gait was the main initial symptom, followed by vertigo and oscillopsia, and cerebellar signs were detected in nearly 100% of the patients. In contrast, extracerebellar signs were relatively mild and infrequent. The results of neuro-otological examination performed in 22 patients suggested the purely cerebellar abnormalities of ocular movements in nature. There was a close relationship between downbeat positioning nystagmus (DPN) and positioning vertigo, which became more common in the later stage. We conclude that total number of CAG repeat-units in both alleles is a good parameter for assessment of age of onset in SCA6 including homozygous patients. In addition, clinical and neuro-otological examinations suggested that SCA6 is a disease with predominantly cerebellar dysfunction.

SYNOPSISInvestigations were carried out regarding the effect of annealing of ethylene-propylene block copolymer (block PP) moldings on their tensile impact strength (TIS) , brittle temperature (Tb) , and other mechanical properties. Annealing near the melting point improves TIS and Tb as the result of recrystallization. With a system in which a minute amount of talc is added as a nucleating agent, the degree of improving TIS through annealing is considerably less than that with a nonnucleated system. The effect of annealing on the impact strength is due to changes of fine texture and morphology of crystallites and is explicable by recrystallization and polymer diffusion. 0 1992 John Wiley & Sons, Inc. INTRO DU CTlO NPolypropylene ( PP ) has various excellent properties as a general purpose resin, such as thermal resistance, rigidity, and chemical resistance. However, its greatest disadvantages are its low impact strength and high Tb temperature, which can be improved by copolymerization with another olefin (generally with ethylene) or blending with an elastomer, with inevitably decreasing the high rigidity characteristics of PP.We have already proposed that annealing of PP blends after their molding is effective as a means of improving impact strength and Tb without sacrificing rigidity.'v2 There have also been reported some similar ~t u d i e s .~.~ Commercial block polypropylenes have been produced through the first-stage polymerization to give a homo-PP or a random copolymer of propylene with a small amount of ethylene, followed by the second stage to effect copolymerization of propylene and ethylene. In some cases, a small amount of polyethylene (PE) has been produced in the second-stage polymerization. Accordingly, a block PP can be regarded as a highly complicated composite of polypropylene, poly (ethylene-co-propylene) ( P E P ) , and p~lyethylene.~-~ * To whom correspondence should be addressed. In the present report, in the same way as with the study on PP blends, we studied the annealing effect on several commercial block PPs regarding mechanical properties and morphology. EXPERIMENTALAll polymers used were block PPs produced by Tokuyama Soda Co., among which block PP-A and PP-B were of commercial grade and PP-C was a special sample of high ethylene content prepared under similar condition. Table I shows compositions and properties of the polymers, of which characterizations were conducted in the same manner as in the previous report' in accordance with ASTM-D1822 and ASTM-D746. The values of TIS in Table I indicate the average of 10 measurements ( n = 10). The standard deviations of TIS values were less than 10% of the average values. The values of Tb were determined by the statistical law with the data measured at least at five different temperatures. Other values in Table I were the average of the data measured with five test specimens. Measurement of isothermal crystallization velocity was made by a differential scanning calorimeter ( Perkin-Elmer Co., Model DSC-lB), by first melting the sample i...

No abstract

This report concerns a clinicopathological study of three additional patients with corticobasal degeneration (CBD), described here for the first time, and a clinicopathological correlation between pyramidal signs and upper motor neuron involvement, in ten autopsy cases of CBD, including seven cases reported by us previously. We investigated pyramidal signs, including hyperreflexia, Babinski sign, and spasticity, and involvement of the primary motor cortex and pyramidal tract, focusing on the astrocytosis of the fifth layer of the primary motor cortex. Pyramidal signs were observed in six (60%) of the ten cases. Hyperreflexia was evident in six patients (60%), with spasticity being observed in three patients (30%). Loss of Betz cells associated with prominent astrocytosis and presence of ballooned neurons in the fifth layer of the primary motor cortex was observed in all ten cases. In all cases, involvement of the pyramidal tract was obvious in the medulla oblongata, without involvement of the pyramidal tract in the midbrain. Constant and severe involvement of the fifth layer of the primary motor cortex, including the Betz cells, has not previously been reported in CBD. We suggest that the pyramidal signs in CBD have been disregarded.