A continuing high incidence of subacute sclerosing panencephalitis (SSPE) in the Eastern Highlands of Papua New Guinea.

The aims of this descriptive study were to confirm the high incidence of subacute sclerosing panencephalitis (SSPE) previously reported from Papua New Guinea (PNG) and to relate SSPE to previous measles vaccination and measles illness. From February 1997 to April 1999 we diagnosed a total of 55 patients with SSPE at Goroka Base General Hospital in Eastern Highlands Province (EHP) of PNG. The diagnosis was based on high cerebrospinal fluid and serum measles virus antibody titres with progressive neurological disorder and myoclonic jerks. Of these 55 patients 42 were from EHP, including 32 whose onset was in the 2-year period 1997-1998. The annual incidence of SSPE in EHP in these 2 years was 98 per million population under 20 years of age, the highest ever reported. This incidence was more than ten times higher than the highest incidence in the prevaccine era reported from elsewhere. The mean age of onset of SSPE was 7.7 years (range 2.8-14.8 years) and the interval between measles and the onset of SSPE, where known, had a mean of 5.9 years and a range of 2.5-11.1 years. Among the SSPE patients 19 had a documented history of measles vaccination. Eight of these 19 also had documentation of previous measles illness; of these, seven were vaccinated after the development of measles and one was vaccinated 20 days before measles illness. Two non-SSPE children received vaccination twice which was documented and subsequently developed measles which was also substantiated by documentation. Two patients with SSPE yielded amplified nucleotide sequences of measles virus that were different from any of the vaccine strains. We found no evidence to implicate measles vaccination in the development of SSPE.

'Iatrogenic' Wernicke's encephalopathy in Japan.

'Iatrogenic' Wernicke's encephalopathy has appeared to occur more frequently in Japan, probably induced by the change of our Japanese national health insurance policy in 1992. We report 4 nonalcoholic patients with such Wernicke's encephalopathy, which occurred during the early postoperative oral food intake period following intravenous nutrition without vitamin supplements. We analyzed the medical records of 4 patients, 3 men and 1 woman, aged between 55 and 71 years, who were admitted to our hospital between 1992 and 1995. Three patients underwent gastrointestinal surgery and 1 suffered chronic pyothorax. We diagnosed our patients as having Wernicke's encephalopathy based on typical neurological abnormalities, in addition to typical cranial magnetic resonance image findings, low serum vitamin B(1) levels, or both. Although all of the patients were treated with vitamin B(1) and showed some improvement, 1 patient developed Korsakoff syndrome, 2 made incomplete neurological recovery, and 1 died. We speculated that the body vitamin B(1) stores had been decreasing in our patients who did not receive any vitamin supplements during intravenous hyperalimentation or hydration. Subsequent administration of high calorie and high carbohydrate oral diets increased the demand for vitamin B(1), further depleting the vitamin stores, thereby causing 'iatrogenic' Wernicke's encephalopathy. The change of our national health insurance policy in 1992 discouraged the routine administration of vitamins, probably causing Wernicke's encephalopathy in our patients.

Vertical antiresonant reflecting optical waveguide coupler for three-dimensional optical interconnects: optimum design for large tolerance, high coupling efficiency, and short coupling length.

A compact antiresonant-reflecting-optical-waveguide-(ARROW-) type vertical coupler for three-dimensional optical interconnects was demonstrated. The coupler consists of stacked ARROW's channeled by the stripe lateral confinement structure, and each waveguide is completely separated by a thin metal film in the separation region. In the coupling region the intermediate cladding of a previous coupler was made of the same material as that of the first cladding or the core. However, we had to overcome the problem that both the high coupling efficiency and the large fabrication tolerance cannot be achieved simultaneously. Thus we incorporated an intermediate cladding made of a material different from that of the core and the first cladding. The refractive index and the thickness of the intermediate cladding were optimally designed to achieve large fabrication tolerance and a short coupling length with a high coupling efficiency. The coupling length was reduced from 4.1 to 0.8 mm, and a high coupling efficiency of 96% was experimentally demonstrated.

Monolithic formation of thin films on the vertical surface of a substrate by a dual-ion-beam sputtering technique.

We have developed a novel method for the selective deposition of thin films on the vertical surface of a planar substrate with a vertical step. This was done with a dual-ion-beam sputtering apparatus that is equipped with two ion-beam sources. Using this technique a multilayer filter was monolithically formed on the vertical surface of a Si substrate on which a photodetector had been fabricated, and clear filtering-photodetecting characteristics were observed. This technique can be applied to the monolithic integration of thin-film devices and waveguide-type optical devices with a vertical end facet.

[A case of variant Gerstmann-Sträussler-Scheinker disease with the mutation of codon P105L].

Here we present a case of variant GSS disease with mutations in codons 1055 and 129 in a prion protein. The patient was a 54-year-old male, who developed weakness in the lower limbs and spastic, wide-based gait at the age of 46 years. Subsequently he developed dementia and spastic quadriplegia at the age of 49. He had marked pseudobulbar palsy at the age of 50 and became bed-ridden in decorticated posture at teh age of 53. CT and MRI examinations revealed marked atrophy of the frontal and temporal lobes, but the occipital lobes and the cerebellum were spared. His sister had been reported by Amano, et al. in 1992 as a case of variant GSS syndrome, who had very similar clinical features, and had numerous prion protein positive plaques in her cerebral cortex at the time of autopsy. His sister was confirmed to have the same mutations in a prion protein as the present case in later genetic studies.

Dissociated changes of frontal and parietal somatosensory evoked potentials in sleep.

We studied the changes of frontal and parietal somatosensory evoked potentials (SEPs) in the awake state versus different stages of sleep in 10 normal adult subjects. Frontal and parietal SEP components were affected differentially as sleep stages progressed. In general, the amplitudes of frontal components, notably P22, were increased in sleep, whereas the amplitudes of parietal components were decreased in sleep. A sensitive waveform change from the awake state to sleep was present in the frontal response, where a subtle notched negativity, termed "N40," was present only in the awake state and quickly dissipated in all stages of sleep, including stage 1. The amplitude changes from the awake state to stage 3/4 sleep were neither linear nor parallel among SEP components. The most discordant changes occurred in stage 3/4. The amplitudes for the frontal N18-P22-N30 complex and parietal N20-P26-N32 complex increased from stage 2 to stage 3/4, while those for frontal N30-fP40 and parietal N32-pP40 decreased. In contrast to these divergent amplitude changes, the latencies of all components except P14 and frontal N18 showed progressive prolongation from the awake state to slow-wave sleep. The SEP waveforms and latencies in REM sleep approximated those in the awake state, although amplitudes for frontal peaks still remained slightly higher and amplitudes for parietal peaks slightly lower. We postulate that interactions of excitatory and inhibitory phenomena are responsible for the component-dependent and sleep-stage-dependent amplitude enhancement or depression in sleep.

Precise recursive formula for calculating spot size in optical waveguides and accurate evaluation of splice loss.

The spot size of a single-mode waveguide was defined from the viewpoint of a least-squares fit of the field profile to a Gaussian profile. The field profile was expanded in terms of Hermite-Gaussian functions, and a new precise recursive formula for calculating the spot size was derived. It was shown that our formula is equivalent to the best fitting of the offset coupling loss to that of a Gaussian profile and keeps its form against the Fourier transform that corresponds to the diffraction in the same manner as the Gaussian profile. The accuracy of conventional formulas and our new spot-size formula was compared with the exact value defined from the viewpoint of a least-squares fit to a Gaussian profile, and it was shown that our recursive formula is the most accurate of the approximate formulas. Next we proposed a new formula for calculating the splice loss between two waveguides and showed that our formula is more accurate than the conventional one, which involves only the spot size.

The effects of stimulus rates upon median, ulnar and radial nerve somatosensory evoked potentials.

We examined the effect of stimulus rates on the somatosensory evoked potential (SEP) amplitude following stimulation of the median nerve (MN) and the ulnar nerve (UN) at the elbow or wrist, and the radial nerve (RN) at the wrist in 12 normal subjects. We measured the amplitude of frontal (P14-N18-P22-N30) and parietal peaks (P14-N20-P26-N34) at a stimulus rate of 1.1, 3.5 and 5.7 Hz. The amplitude attenuation was found at frontal P22 and N30 and to a lesser degree at parietal N20 and P26 peaks with an increasing stimulus rate from 1.1 to 5.7 Hz. The amplitude attenuation was greatest at the elbow when compared to the wrist stimulation for both MN and UN. The attenuation was least for wrist stimulation for the RN. The UN block by local anesthesia just distal to the stimulus electrode at the elbow abolished the amplitude attenuation caused by the fast stimulus rate. The observed amplitude attenuation with the faster stimulus rate is probably due, in part, to interference from the "secondary" afferent inputs. The secondary afferent inputs arise from peripheral receptor stimulation (muscle, joint and/or cutaneous) as a subsequent effect of efferent volleys initiated from the point of stimulation. The greater number of peripheral receptors being activated as more proximal sites of stimulation in a mixed nerve would result in greater attenuation of the SEP recorded from scalp electrodes. We postulate that the attenuation of frontal peaks by the fast stimulus rate is due to the frontal projection of interfering "secondary" afferent inputs.

Spot size transformer with a type-B antiresonant reflecting optical waveguide.

A type-B antiresonant reflecting optical waveguide was incorporated into a spot size transformer to achieve precise control of the spot size without precise control of the refractive index. Owing to the optimum design, a low insertion loss of 0.9 dB and a large transformation ratio of 5.6 were successfully obtained.

High efficiency light coupling from antiresonant reflecting optical waveguide to integrated photodetector using an antireflecting layer.

The dispersion characteristics and radiation loss characteristics of ARROW (antiresonant reflecting optical waveguide), a novel single-mode slab waveguide, are analyzed in detail. The mechanism by which the waveguide produces a large amount of light radiation from the waveguide core to the semiconductor substrate is explained and some approximate formulas of propagation characteristics are obtained, which are useful for the design of ARROW. Two novel integrated structures of ARROW and photodetector are proposed to realize high coupling efficiency from waveguide to photodetector, small device size, and easy fabrication process. In these structures, an antireflecting (AR) layer is introduced to greatly enhance coupling efficiency. Their performance is discussed compared with the conventional waveguide structure. It is shown theoretically and experimentally that a high coupling efficiency (>90%) is achievable with short detector length in the ARROW structures.

Isolation, properties and amino acid sequences of a phospholipase A2 and its homologue without activity from the venom of a sea snake, Laticauda colubrina, from the Solomon Islands.

A phospholipase A2, Laticauda colubrina phospholipase A2 II (LcPLA-II), and a phospholipase A2 homologue, Laticauda colubrina phospholipase A2 homologue I (LcPLH-I), were isolated from the venom of the yellow-lipped sea snake, Laticauda colubrina, from the Solomon Islands. LcPLA-II showed phospholipase A2 activity towards egg-yolk phosphatidylcholine (24 mumol/min per mg at optimal conditions at 37 degrees C) and lethal potency (LD50 45 micrograms/kg body wt. intravenously in mice). Both of the activities were lost by treatment with p-bromophenacyl bromide. LcPLH-I showed neither phospholipase A2 activity nor lethal potency at a dose of 4.5 mg/kg body wt. in mice. It was not modified by the treatment with p-bromophenacyl bromide. LcPLA-II and LcPLH-I bound Ca2+ at a 1:1 molar ratio with KCa values of 105 microM and 44 microM at pH 8.0 respectively. Elucidation of the amino acid sequences of these two proteins showed that each protein consisted of a single chain of 118 amino acid residues, including 14 half-cystine residues. The two sequences are different from each other at 22 residues and highly homologous to those from other sources. The essential histidine residue for the phospholipase A2 activity at position 48 is replaced by an asparagine residue in the homologue LcPLH-I. Details of the separation of the peptides obtained by proteinase digestions of LcPLA-II and LcPLA-I and the determination of their amino acid sequences are given in Supplementary Publication SUP 50145 (14 pages), which has been deposited at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1988) 249, 5.

Somatosensory evoked potentials in chronic alcoholics with spasticity.

Somatosensory evoked potentials to median and bilateral tibial nerve stimulation were investigated in eight chronic alcoholics with spasticity, 12 patients with alcoholic polyneuropathy, and 11 normal subjects. Central conduction velocities from the third lumbar vertebra to the fifth cervical vertebra and from the 12th thoracic vertebra to the fifth cervical vertebra were significantly lower in the chronic alcoholics with spasticity than in the alcoholic polyneuropathy group and in the healthy nonalcoholic group. The result indicates that chronic alcoholics with spasticity have conduction disturbance in the posterior column and/or the medial lemniscus, which is considered to be due to alcoholic myelopathy and/or a brainstem lesion.

Correction of the amino acid sequences of erabutoxins from the venom of the sea snake Laticauda semifasciata.

The amino acid sequences of erabutoxins a and b were reinvestigated. The previously reported sequences of Gln-His at positions 6 and 7, and of Pro-Ser at positions 18 and 19 of erabutoxins a and b were corrected to His-Gln and Ser-Pro respectively.

Improved distributed-index planar microlens and its application to 2-D lightwave components.

A recent improvement of a 2-D array of distributed-index (DI) planar microlenses is presented to demonstrate a 2-D integrated optical component using a planar microlens array. These components are made by stacking planar microlens arrays and other planar optical devices. The improved planar microlens has f = 2.0 mm, a N.A. = 0.23, and its spherical aberration is very small. A fiber coupler is demonstrated. From a preliminary experiment, it is shown that the coupling loss of each channel is <0.5 dB for coupling 50-micron core DI fibers.

Index profiling of distributed-index lenses by a shearing interference method.

It is demonstrated that the transverse differential interference method is used as a reliable profiling technique for distributed-index rod lenses, and its accuracy and spatial resolution have been made clear. By the use of this technique the index profile of a distributed-index planar microlens which has 3-D index distribution has been measured.

Stacked planar optics: an application of the planar microlens.

In this paper we present a new development of the distributed-index planar microlens of 2.5-3-mm focal length and 0.15 N.A. and also show that it is usable with optical components in fiber communications. We then propose a concept of stacked planar optics consisting of a stack of arrayed planar microlenses and other optical components. From this configuration a 2-D array of optical devices is monolithically available, and many discrete components can be separated from the array. An optical tap array has been fabricated as an example of stacked planar optics.

Differential diagnosis of various thrombocytopenias in childhood by analysis of platelet volume.

Platelet volume was measured in 20 healthy children, 18 patients with acute idiopathic thrombocytopenic purpura (ITP), 24 patients with chronic ITP, 22 patients with aplastic anemia, and 17 patients with acute leukemia in childhood. The authors compared the platelet volume of these patients by use of peak platelet volume (PPV or mode of the platelet volume), mean platelet volume (MPV) and the percent of large platelets (PLP) as parameters of the platelet volume, and then studied the relationship between the platelet volume and the specific gravity of platelets from these patients. The following was the platelet volume of normal children: PPV was 6.7 +/- 1.1 micrometer 3, MPV was 9.9 +/- 1.6 micrometer 3, PLP was 26.0 +/- 7.7%. All parameters of the platelet volume were remarkably large in chronic ITP, but only PPV was small in acute ITP. On the other hand, all parameters were small in both aplastic anemia and acute leukemia. In acute ITP and chronic ITP, the platelet volume returned to normal value after these thrombocytopenias disappeared. The platelet volume, however, still remained small even after remission in acute leukemia. There was better correlation between MPV and PLP than PPV and PLP. The density analysis of the platelets obtained from platelet-rich plasma (PRP) revealed that PLP in each medium (1.010 approximately 1.052) of normal PRP increased slowly in proportion to the increase of specific density of the media. On the contrary, most of large platelets obtained from the patients with acute ITP and chronic ITP were especially contained in the medium of high specific density (1.052). Large platelets of aplastic anemia and acute leukemia, however, were found in both low and high density media. The authors believe that analysis of the platelet volume using above mentioned three parameters would provide good weapon in early differential diagnosos of acute ITP, chronic ITP, and aplastic anemia. And these findings also may suggest the difference of thrombopoiesis between acute ITP and chronic ITP.