Distinct RNA polymerase transcripts direct the assembly of phase-separated DBC1 nuclear bodies in different cell lines

The mammalian cell nucleus is a highly organized organelle that contains membrane-less structures referred to as nuclear bodies (NBs). Some NBs carry specific RNA types that play architectural roles in their formation. Here, we show two types of RNase-sensitive DBC1-containing NBs, DBC1 nuclear body (DNB) in HCT116 cells and Sam68 nuclear body (SNB) in HeLa cells, that exhibit phase-separated features and are constructed using RNA polymerase I or II transcripts in a cell type–specific manner. We identified additional protein components present in DNB by immunoprecipitation–mass spectrometry, some of which (DBC1 and heterogeneous nuclear ribonucleoprotein L [HNRNPL]) are required for DNB formation. The rescue experiment using the truncated HNRNPL mutants revealed that two RNA-binding domains and intrinsically disordered regions of HNRNPL play significant roles in DNB formation. All these domains of HNRNPL promote in vitro droplet formation, suggesting the need for multivalent interactions between HNRNPL and RNA as well as proteins in DNB formation.

Mechanism of karyopherin-β2 binding and nuclear import of ALS variants FUS(P525L) and FUS(R495X)

Mutations in the RNA-binding protein FUS cause familial amyotropic lateral sclerosis (ALS). Several mutations that affect the proline-tyrosine nuclear localization signal (PY-NLS) of FUS cause severe juvenile ALS. FUS also undergoes liquid-liquid phase separation (LLPS) to accumulate in stress granules when cells are stressed. In unstressed cells, wild type FUS resides predominantly in the nucleus as it is imported by the importin Karyopherin-β2 (Kapβ2), which binds with high affinity to the C-terminal PY-NLS of FUS. Here, we analyze the interactions between two ALS-related variants FUS(P525L) and FUS(R495X) with importins, especially Kapβ2, since they are still partially localized to the nucleus despite their defective/missing PY-NLSs. The crystal structure of the Kapβ2·FUS(P525L)PY-NLS complex shows the mutant peptide making fewer contacts at the mutation site, explaining decreased affinity for Kapβ2. Biochemical analysis revealed that the truncated FUS(R495X) protein, although missing the PY-NLS, can still bind Kapβ2 and suppresses LLPS. FUS(R495X) uses its C-terminal tandem arginine-glycine-glycine regions, RGG2 and RGG3, to bind the PY-NLS binding site of Kapβ2 for nuclear localization in cells when arginine methylation is inhibited. These findings suggest the importance of the C-terminal RGG regions in nuclear import and LLPS regulation of ALS variants of FUS that carry defective PY-NLSs.

Siwi levels reversibly regulate secondary piRISC biogenesis by affecting Ago3 body morphology in Bombyx mori

Silkworm ovarian germ cells produce the Siwi‐piRNA‐induced silencing complex (piRISC) through two consecutive mechanisms, the primary pathway and the secondary ping‐pong cycle. Primary Siwi‐piRISC production occurs on the outer mitochondrial membrane in an Ago3‐independent manner, where Tudor domain‐containing Papi binds unloaded Siwi via its symmetrical dimethylarginines (sDMAs). Here, we now show that secondary Siwi‐piRISC production occurs at the Ago3‐positive nuage Ago3 bodies, in an Ago3‐dependent manner, where Vreteno (Vret), another Tudor protein, interconnects unloaded Siwi and Ago3‐piRISC through their sDMAs. Upon Siwi depletion, Ago3 is phosphorylated and insolubilized in its piRISC form with cleaved RNAs and Vret, suggesting that the complex is stalled in the intermediate state. The Ago3 bodies are also enlarged. The aberrant morphology is restored upon Siwi re‐expression without Ago3‐piRISC supply. Thus, Siwi depletion aggregates the Ago3 bodies to protect the piRNA intermediates from degradation until the normal cellular environment returns to re‐initiate the ping‐pong cycle. Overall, these findings reveal a unique regulatory mechanism controlling piRNA biogenesis.

The Sam68 nuclear body is composed of two RNase-sensitive substructures joined by the adaptor HNRNPL

The mammalian cell nucleus contains membraneless suborganelles referred to as nuclear bodies (NBs). Some NBs are formed with an architectural RNA (arcRNA) as the structural core. Here, we searched for new NBs that are built on unidentified arcRNAs by screening for ribonuclease (RNase)-sensitive NBs using 32,651 fluorescently tagged human cDNA clones. We identified 32 tagged proteins that required RNA for their localization in distinct nuclear foci. Among them, seven RNA-binding proteins commonly localized in the Sam68 nuclear body (SNB), which was disrupted by RNase treatment. Knockdown of each SNB protein revealed that SNBs are composed of two distinct RNase-sensitive substructures. One substructure is present as a distinct NB, termed the DBC1 body, in certain conditions, and the more dynamic substructure including Sam68 joins to form the intact SNB. HNRNPL acts as the adaptor to combine the two substructures and form the intact SNB through the interaction of two sets of RNA recognition motifs with the putative arcRNAs in the respective substructures.

RNase Sensitivity Screening for Nuclear Bodies with RNA Scaffolds in Mammalian Cells

The mammalian cell nucleus is highly organized and contains membraneless nuclear bodies (NBs) characterized by distinct resident factors. The NBs are thought to serve as sites for biogenesis and storage of certain RNA and protein factors as well as assembly of ribonucleoprotein complexes. Some NBs are formed with architectural RNAs (arcRNAs) as their structural scaffolds and additional NBs likely remain unidentified in mammalian cells. Here, we describe an experimental protocol to search for new NBs built on certain arcRNAs. RNase-sensitive NBs were identified by monitoring nuclear foci visualized by tagging thousands of human cDNA products.

Prion-like domains in RNA binding proteins are essential for building subnuclear paraspeckles

Paraspeckles are mammalian subnuclear bodies built on a long noncoding RNA and are enriched in RNA binding proteins with prion-like domains; two of these proteins, RBM14 and FUS, use these domains to hold paraspeckles together.

Prion-like domains (PLDs) are low complexity sequences found in RNA binding proteins associated with the neurodegenerative disorder amyotrophic lateral sclerosis. Recently, PLDs have been implicated in mediating gene regulation via liquid-phase transitions that drive ribonucleoprotein granule assembly. In this paper, we report many PLDs in proteins associated with paraspeckles, subnuclear bodies that form around long noncoding RNA. We mapped the interactome network of paraspeckle proteins, finding enrichment of PLDs. We show that one protein, RBM14, connects key paraspeckle subcomplexes via interactions mediated by its PLD. We further show that the RBM14 PLD, as well as the PLD of another essential paraspeckle protein, FUS, is required to rescue paraspeckle formation in cells in which their endogenous counterpart has been knocked down. Similar to FUS, the RBM14 PLD also forms hydrogels with amyloid-like properties. These results suggest a role for PLD-mediated liquid-phase transitions in paraspeckle formation, highlighting this nuclear body as an excellent model system for understanding the perturbation of such processes in neurodegeneration.

How does the royal family of Tudor rule the PIWI-interacting RNA pathway?

PIWI (P-element-induced wimpy testis) proteins are a subset of the Argonaute proteins and are expressed predominantly in the germlines of a variety of organisms, including Drosophila and mammals. PIWI proteins associate specifically with PIWI-interacting RNAs (piRNAs), small RNAs that are also expressed predominantly in germlines, and silence transposable DNA elements and other genes showing complementarities to the sequences of associated piRNAs. This mechanism helps to maintain the integrity of the genome and the development of gametes. PIWI proteins have been shown recently to contain symmetrical dimethyl arginines (sDMAs), and this modification is mediated by the methyltransferase PRMT5 (also known as Dart5 or Capsuleen). It was then demonstrated that multiple members of the Tudor (Tud) family of proteins, which are necessary for gametogenesis in both flies and mice, associate with PIWI proteins specifically through sDMAs in various but particular combinations. Although Tud domains in Tud family members are known to be sDMA-binding modules, involvement of the Tudor family at the molecular level in the piRNA pathway has only recently come into focus.

Dss1 associating with the proteasome functions in selective nuclear mRNA export in yeast

Dss1p is an evolutionarily conserved small protein that interacts with BRCA2, a tumor suppressor protein, in humans. The Schizosaccharomyces pombe strain lacking the dss1(+) gene (Deltadss1) shows a temperature-sensitive growth defect and accumulation of bulk poly(A)(+) RNA in the nucleus at a nonpermissive temperature. In situ hybridization using probes for several specific mRNAs, however, revealed that the analyzed mRNAs were exported normally to the cytoplasm in Deltadss1, suggesting that Dss1p is required for export of some subsets of mRNAs. We identified the pad1(+) gene, which encodes a component of the 26S proteasome, as a suppressor for the ts(-) phenotype of Deltadss1. Unexpectedly, overexpression of Pad1p could suppress neither the defect in nuclear mRNA export nor a defect in proteasome function. In addition, loss of proteasome functions does not cause defective nuclear mRNA export. Dss1p seems to be a multifunctional protein involved in nuclear export of specific sets of mRNAs and the ubiquitin-proteasome pathway in fission yeast.

Detailed analysis of the latencies of median nerve somatosensory evoked potential components, 1: selection of the best standard parameters and the establishment of normal values

In order to objectively select the standard parameters best suited for the evaluation of somatosensory conduction in median nerve somatosensory evoked potentials (SEP), we performed a detailed statistical analysis of intersubject variability for the latencies of SEP components based on the recordings of 62 normal subjects. Multiple regression analyses for height, age, (age--20)2 and sex were performed for the latencies of 13 components and 78 intercomponent intervals, and the residual variance was used as an indicator of the stability of each parameter. As a result, N9 onset in EPi-NC lead, N11' onset in C6S-Fz lead, P13/14 onset in scalp-NC leads, for which N13' onset recorded in C6S-Fz lead may substitute, and N20 onset in CPc-Fz lead were the most stable time-points selected as standards. N11 onset in C6S-NC, which other authors have recommended as the standard point representing spinal entry, was not recorded consistently, and P11 onset in scalp-NC leads was also unstable. N20 peak and N13'-N20 interval (equivalent to conventional central conduction time) were extremely unstable. We presented the nomograms to find normal limits of the standard parameters corresponding to the given values of the predictor variables (height, age or sex). As the standard recording montage in routine clinical examinations, we recommended a simple method using Fz reference, for example (1) EPi-Fz, (2) C6S-Fz, (3) CPc-Fz, because this montage is sufficient to measure the stable standard parameters.

Acute disseminated encephalomyelitis confined to brainstem

A 21-year-old man was troubled with a subacute history of brainstem involvement and a leukocyte pleocytosis in the cerebrospinal fluid. Magnetic resonance imaging (MRI) demonstrated a massive lesion with Gd enhancement in the pons. Steroid therapy, not antiviral drugs, was dramatically effective for the mass reduction and symptom improvement. Over 4 years no recurrence has been recognized, so this case was diagnosed to be an unusual case of acute disseminated encephalomyelitis (ADEM). ADEM must be included in the differential diagnosis for a brainstem mass in MRI.

Observation of charge state and conformational change in immobilized protein using surface plasmon resonance sensor

Behaviors of proteins immobilized on a solid surface were investigated using BIACORE, a biosensor utilizing surface plasmon resonance. This sensor is usually used for analyzing binding events during biomolecular interactions. Here we propose a novel use of this sensor to monitor two kinds of intramolecular changes in immobilized proteins. Several proteins were covalently attached to dextran chains on the sensor surface in the flow cell and were then exposed to a series of buffers with varying pH. Signal changes derived from changes of refractive index around the sensor surface were detected during and after the exposure to each of these buffers, which we denoted as in situ values and postvalues, respectively. The in situ value reflects the behavior of immobilized proteins in these buffers and was revealed to have a correlation with total charge state of the proteins, while the postvalue reflects how immobilized proteins react after the exposure and was suggested to represent the degree of conformational changes of the proteins. This method is expected to be applicable to various analyses and can provide us with new information about the behavior of proteins on solid phase.

Pure alexia from a posterior occipital lesion

The authors report a patient with pure alexia (letter-by-letter reading) selectively impaired for kana (Japanese phonograms), cerebral achromatopsia, and right lower quadrantanopsia after hemorrhage in the left posterior occipital lobe, mainly under the lateral occipital gyri. The patient also could not recognize some single-character kana, nor could he discriminate between two shapes of a similar size. The authors believe that the posterior occipital lobe, including the lateral occipital gyri, is specialized to recognize kana characters in this patient.

Monitoring of the refolding process for immobilized firefly luciferase with a biosensor based on surface plasmon resonance

In order to examine the possibility of the use of a surface plasmon resonance (SPR) sensor for real-time monitoring of the process of refolding of immobilized proteins, the refolding of firefly luciferase immobilized on a carboxymethyldextran matrix layer was analyzed. The SPR signal of the immobilized luciferase decreased after unfolding induced by GdnCl and increased gradually in the refolding buffer, while there was no signal change in the reference surface lacking the immobilized protein. The decrease in the SPR signal on unfolding was consistent with the difference between the refractive indices of the native and unfolded protein solutions. The effects of blocking of the excess NHS-groups of the matrix layer on the refolding yield were examined by means of an SPR sensor. The results were consistent with those obtained with the enzymatic activity assay, indicating that the changes in the SPR signal reflected the real-time conformational changes of the immobilized protein. Hence, an SPR biosensor might be used for monitoring of the process of refolding of immobilized proteins and as a novel tool for optimization of the refolding conditions. This is the first demonstration that SPR signal changes reflect the conformational changes of an immobilized protein upon unfolding and refolding.

Expanded-Bed Protein Refolding Using a Solid-Phase Artificial Chaperone

An efficient solid-phase protein refolding method based on artificial chaperone-assisted refolding is proposed. The method employs insoluble cyclodextrin polymer beads and the expanded-bed technique. Alpha-glucosidase, whose spontaneous refolding yield from a urea-denatured state is up to 30% at a protein concentration of up to 10 microg/ml, could be refolded with a yield that was improved more than two-fold at a protein concentration more than five-fold higher when protein solution was circulated through an expanded bed under optimized conditions. Unlike the conventional liquid-phase artificial system, further steps to purify the refolded product, which are generally needed to remove detergent-cyclodextrin complex and excess cyclodextrin, were unnecessary. In addition, the polymer beads were reusable after simple washing with water, and the continuous system is suitable for easy-scale-up using commercially available devices. This new method is considered to be a powerful means of achieving large-scale protein refolding for industrial protein production.

Rapidly progressive polymyositis with elevated antiacetylcholine receptor antibody activity

We report a 51-year-old woman with polymyositis accompanied by a high titer of antiacetylcholine receptor antibody. The patient presented with weakness of grip strength followed by rapidly progressive dyspnea, which required mechanical ventilation. She was treated with a glucocorticoid and came off the respirator one week later. Antiacetylcholine receptor antibody activity was elevated in the acute phase and decreased during recovery, although other signs of myasthenia gravis were negative. This patient suggested that in cases of rapidly progressive bulbar palsy and limb muscle weakness, it is necessary to include polymyositis associated with elevated antiacetylcholine receptor antibody activity in the differential diagnosis.

Neuropathological findings of Onuf's nucleus and its significance

Onuf's nucleus is a small group of cells which are located mainly in the anterior horn of the second sacral segment of the spinal cord. This paper describes the history of studies relating to this nucleus including a discussion of its relation with the various pathological studies which have been made.

Direct refolding of recombinant human growth differentiation factor 5 for large-scale production process

An efficient downstream process for the production of recombinant human growth differentiation factor 5 (rhGDF5) has been developed for industrial application utilizing a novel "direct refolding" method. In this method, the starting material is an inclusion body produced in Escherichia coli, and the critical step is the direct refolding step that follows directly after solubilization of the inclusion body. rhGDF5 can be refolded at a markedly high concentration of 2.4 mg.ml(-1), which is 24 times that hitherto achieved by the proteins of the TGF-beta superfamily. The refolding yield is 63%, and after purification by diafiltration, isoelectric precipitation and reverse-phase chromatography, the final purification yield is 20% with purity higher than 99%. The yield is more than twice that of a conventionally established process having three chromatography steps and the purity is equivalent. The first pilot-scale trial shows a refolding yield of 51% and a final yield of 11%. The final yield is 1.4 times that of the conventional process, and further optimization at pilot-scale is expected to bring this figure up to or above that of laboratory-scale. As a result, the calculated production cost of rhGDF5 has been reduced dramatically. This type of efficient and simple process is beneficial particularly in the large-scale production of recombinant proteins in which high yield and quality are required.

[The clinical usefulness of high-dose intravenous immunoglobulin therapy for chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy]

To explore the optimum dose of intravenous immunoglobulin (i.v.Ig) for treating patients with chronic inflammatory demyelinating polyrneuropathy and multifocal motor neuropathy, we compared the usefulness of i.v.Ig among 3 treatment doses. Fifty-nine patients were randomly divided into three treatment dosage groups: 20 patients for Group I using 50 mg/kg/day x 5 days, 19 patients Group II using 200 mg/kg/day x 5 days, and 20 patients Group III using 400 mg/kg/day x 5 days. We assessed clinically and electrophysiologically the effectiveness of the treatment at 5 weeks after the initial infusion. For patients in Group I and II who had not improved (or worsened) with the first treatment, we gave a one-step larger dose in the second treatment (i.e. 200 mg/kg/day x 5 days for those who had been given 50 mg/kg/day x 5 days, 400 mg/kg/day x 5 days for those who had been given 200 mg/kg/day x 5 days) after more than 9 weeks. We found that 15% of the patients in Group I, 21% in Group II and 60% in Group III improved dose-dependently with the first intravenous immunoglobulin treatment. Seven (47%) of 16 patients in Group I and 4 (40%) of 11 patients in Group II improved after the second treatment with larger doses. Adverse reactions including chill sensation, fever, skin eruption and increase in blood GOT and GPT levels were transient and mild. One patient in Group III developed left hemiparesis showing the small infarction in the right thalamus during the course of the treatment, but the symptom was mild. In conclusion, the high-dose intravenous immunoglobulin therapy (400 mg/kg/day x 5 days) is useful for treating patients with CIDP and MMN, although care must be taken of the risk of causing cerebral infarctions.

Detailed analysis of the latencies of median nerve somatosensory evoked potential components, 2: Analysis of subcomponents of the P13/14 and N20 potentials

Detailed analysis of P13/14 and N20 wavelets was performed for 62 normal subjects and patients with various lesions along the somatosensory pathway. A histogram of the latencies of all the identified P13/14 wavelets (measured from P13/14 onset) demonstrated three latency-groups, which were named P13, P14a and P14b subcomponents. The relationship between the three newly identified subcomponents and the conventional naming of P13 and P14 was inconstant, indicating the ambiguity of the latter. P14b was most prominent in the contralateral central region, and therefore a P15 positivity slightly after P14b was often recorded in the CPc-Fz and CPc-CPi leads (CPc and CPi are centroparietal electrodes contralateral and ipsilateral to the stimulation). P14b/P15 was lost even in patients with cortical lesions, and thalamocortical fibers were assumed for its origin. The CPc-Fz and CPi-Fz leads registered a low negativity named broad N13', suggesting frontal predominance of the overall P13/14 complex. Both P13 and P14a were identified in a patient with a pontine lesion, and a caudal brainstem origin for both was suspected due to the onset of two repetitive bursts of the ascending lemniscal volley. We refuted the presynaptic origin of the scalp P13 potential and pointed out that a prolonged and/or polyphasic P11 frequently observed in patients with high cervical lesions can be mistaken as scalp P13. A histogram of the latencies of all the identified negative wavelets of N20 in the CPc-Fz lead (measured from N20 onset) revealed five definite latency-groups, which were named N20a, N20b, N20c, N20d and N20e subcomponents. The highest peak of N20 actually corresponded to either N20b, N20c or N20d, and this uncertainty, which must be related to intracortical processes, resulted in a large instability of the N20 peak latency as well as the age and sex dependence of the N20 onset-peak interval, both of which were demonstrated by our preceding study (Sonoo, M., Kobayashi, M., Genba-Shimizu, K., Mannen, T. and Shimizu, T. Detailed analysis of the latencies of median nerve SEP components, 1: selection of the best standard parameters and the establishment of the normal values. Electroenceph. clin. Neurophysiol., 1996b, 100: 319-331). Negative subcomponents in the CPc-NC lead and positive subcomponents in the Fz-NC lead constituted mirror images of each other, which suggested that these subcomponents were generated within area 3b.

Cortical dysgenesis in a patient with Turner mosaicism

In a patient with Turner mosaicism who had mental retardation, epilepsy and cerebellar ataxia, MRI showed cerebellar atrophy and a bizarre cortical dysgenesis of the cerebrum, which was considered to comprise a mixture of relatively normal gyri and structures resembling pachygyria and lissencephaly. The karyotype of the patient was 45,X/47,XXX, but the brain dysgenesis could not be explained solely on the basis of this mosaicism, which is rarely associated with a gross abnormality in brain pathology. Abnormality of the X chromosome seems to have some potential for inducing cortical dysgenesis, and this case may be partially attributable to an abnormal locus on the X chromosome.

Some unusual responses of astrocytes to ghost tangles in a long duration case of juvenile Alzheimer's disease: an electron microscopic study

The ghost tangles (GTs) in usual Alzheimer's disease are separated into small bundles of abnormal straight filaments by many invading astrocytic processes lacking a basal lamina (BL). An electron microscopic study of GTs in the Ammon's horn of a case of juvenile Alzheimer's disease of 25 years' duration, however, revealed that only a small number of astrocytic processes had infiltrated the GTs, resulting in the GTs being composed of large bundles. Moreover, the majority of glial processes that had invaded or apposed GTs possessed an interrupted but still fairly well-developed BL with hemidesmosome-like profiles. Although pia-arachnoid cells are required for astrocytes to form a continuous BL, astrocytes can have a segmental BL on their surface facing even empty intercellular spaces within the brain parenchyma. The much greater frequency and better development of the GT-associated BL in our case indicate that the GT filaments somehow increased the ability of astrocytes to form a BL. On the other hand, the scarcity of GT-invading astrocytic processes implies that many of the glial processes that had once penetrated GTs had been withdrawn, with the result that GTs escaped expectable endocyto-phagocytosis by astrocytes.

[Dose-response relationship in the treatment of cervical dystonia with botulinum toxin type A (AGN 191622)--a phase II study]

Injection of botulinum toxin type A has been the treatment of choice for spasmodic torticollis for several years. Although previous reports demonstrate its effectiveness and safety, the treatment strategy has been empirical. The present study, using the freeze-dried crystalline botulinum toxin type A (AGN 191622; Allergan Inc., Irvine, CA), aimed to compare the efficacy among three treatment groups divided into low, medium and high dosage levels. Fifty-one patients who entered the study were grouped into low-dose (60 units/session), medium-dose (120 units/session) and high-dose (240 units/session) groups. Two patients (one in low-dose group and the other in high-dose group) were excluded from the assessment of efficacy because they dropped out in the early phase of the study. One experienced worsening of an existing psychosis and the other developed an acute respiratory infection. Injection sites were decided individually by palpation. If the clinical response was not satisfactory four weeks after an injection, the patient was re-injected with the same dose of toxin. The follow-up period was 14 weeks from the initial injection. The results showed that the high-dose group improved more than the other groups in the parameters of severity of symptoms and subjective benefit (p = 0.000). Also, fewer injections were required in the high-dose group to achieve substantial clinical benefit. Although the mean reduction in Tsui's score was not statistically significant among the groups, the "marked improvement" was seen more frequently in the high-dose group (p = 0.033). Unfavorable adverse effects including excessive weakness and dysphasia were always mild and transient.(ABSTRACT TRUNCATED AT 250 WORDS)

Three-dimensional MR imaging of brain surface anomalies in Fukuyama-type congenital muscular dystrophy

Fukuyama-type congenital muscular dystrophy (FCMD), the second most common childhood muscular dystrophy in Japan, is characterized by the association with severe brain anomalies such as pachygyria and focal interhemispheric fusion. Conventional imaging techniques such as X-ray CT scan and MRI are ineffective for visualization of these brain surface anomalies. Here we investigated the efficacy of three-dimensional (3-D) reconstruction of brain surface MR images for the detection of brain anomalies in FCMD patients. 3-D brain surface MR images clearly visualized anomalies of cerebral gyrus such as pachygyria, as well as focal interhemispheric fusion. In addition, reconstructed horizontal images visualized structural derangement such as abnormal protrusion of white matter into gray matter. MR image abnormalities were confirmed by autopsy in 1 patient. These abnormalities were never observed in Duchenne muscular dystrophy (DMD) patients. Our results indicate the efficacy of the present method for the differential diagnosis between FCMD and DMD with severe mental retardation, which is essential for the genetic study to identify the causative gene of FCMD.

[MRI of anterior spinal artery syndrome--chronological study]

We reported two cases of anterior spinal artery syndrome serially observed by MRI of the spinal cord. On the 8th and 10th days respectively, MRI with Gd revealed high signal intensity areas which were thought to be located in the anterior horn region of the two patients. On the 28th and 37th days respectively, there was no enhancement on the MRI with Gd. This enhancement in the anterior horn region might be correlated with vulnerability of the anterior horn to ischemia, and capillary proliferation due to simultaneous appearance of this enhancement with that of capillary proliferation after liquidization of the anterior horn. Therefore, the enhancement on the MRI indicates a correspondence with pathological findings and is be characteristic of anterior spinal artery syndrome.

Infarction of the unilateral posterior horn and lateral column of the spinal cord with sparing of posterior columns: demonstration by MRI

Infarction of the spinal cord, particularly in the distribution of the posterior spinal arteries, is rare. Twenty seven cases of posterior spinal artery syndrome have been reported. In all cases, the posterior columns were affected, and in all but two, the lesions were bilateral. Here a 49-year-old woman is reported, who was affected with lumbar cord infarction in the distribution of the posterior spinal arteries, diagnosed by MRI and clinical presentation. This case is of special interest because of sparing of the posterior columns and the unilateral nature of the lesion, even though the infarction occurred in the distribution of the posterior spinal arteries.

Functional localization in the Onufrowicz nucleus in man

Neuropathological examination of a patient who died 45 days after the rectal amputation revealed axonal reaction of the motor neurons mainly in the dorsomedial portion of the Onufrowicz nucleus. Apparently normal motor neurons were found only in the ventrolateral portion. Also found in the present case was the localized distribution of chromatolytic neurons in the sacral intermediolateral cell column. While the ventral portion of it showed chromatolysis, the lateral portion was well preserved. These findings are in accordance with those obtained from the animal studies which demonstrated the functional localization of the sacral motor neuron pools into the anorectal innervation centers and the vesico-urinary centers.

The interval between the positive peak of premyoclonus spike and the onset of myoclonus is shorter than the cortical latency in cortical myoclonus

In 6 patients with cortical myoclonus, the intervals between the positive peak of the premyoclonus cortical spike and the onset of the myoclonic jerk [interval (Sp-Mcl)] were precisely measured by the computer-assisted jerk-locked averaging method. The intervals (Sp-Mcl) were 13.0-15.8 ms for the abductor pollicis brevis, 8.0-10.4 ms for the extensor digitorum communis and 5.5 ms for the biceps brachii, respectively. These were apparently shorter than the normal latencies of the responses elicited by transcranial cortical stimulation. The difference between the interval (Sp-Mcl) and the spinal latency was -0.8 to 3.5 ms, which was not long enough for the time required for the descending volleys going down from the cortex to the spinal cord. We have concluded that the motor cortex is activated before the positive peak of the premyoclonus spike in cortical myoclonus.

Inherited amyloid polyneuropathy type IV (gelsolin variant) in a Japanese family

We describe a Japanese family with familial amyloid polyneuropathy type IV. The family originates from central Japan, Nagano prefecture, and is unrelated to Finnish or other Caucasian populations. Of 42 members in three generations, 14 individuals (5 men, 9 women) are affected by corneal lattice dystrophy, cranial neuropathy, mild peripheral neuropathy, and skin changes. Polarizing microscopy and immunohistochemistry studies of skin biopsy samples demonstrated abundant amyloid deposits, which bound an antigelsolin monoclonal antibody. Direct sequence analysis of a DNA fragment spanning codon 187 of plasma gelsolin complementary DNA and restriction analysis using a modified polymerase chain reaction demonstrated a single base substitution, guanine to adenine, at nucleotide position 654, which is identical to the mutation in Finnish familial amyloid polyneuropathy type IV. This strongly suggests that the mutation causes the familial amyloid polyneuropathy type IV phenotype regardless of ethnic background.

Stimulation of corticospinal pathways at the level of the pyramidal decussation in neurological disorders

A newly developed technique of brainstem stimulation was applied in 14 normal subjects and 23 patients with various neurological disorders. The electromyographic (EMG) responses of limb muscles following cortical, brainstem and cervical stimulation were recorded. The cortical-brainstem conduction time and brainstem-cervical conduction time were then calculated from the difference in latency between the two sites of stimulation. From the regression lines of the relationship between the normal conduction times in the first dorsal interosseous muscle and the length of the descending tracts, the site of activation by brainstem stimulation was estimated to lie near the cervical-medullary junction. The most distal lesion causing prolongation of cortical-brainstem conduction time was a small cerebral infarction in the lower pons. Herniation of the third cervical spinal disc was the most rostral lesion resulting in delayed brainstem-cervical conduction time and normal cortical-brainstem conduction time. These observations suggest that activation occurs at the level of the cervical-medullary junction where the pyramidal decussation lies. The conduction velocities of the activated tracts estimated from the regression lines for normal individuals were 57-92 m/s. In patients with supratentorial lesions, the threshold for brainstem stimulation was abnormally high. The abnormal findings in this test were correlated significantly with the clinical pyramidal signs. This suggests that the EMG responses elicited by brainstem stimulation are mediated mainly by the corticospinal tract. We conclude that the brainstem stimulation technique would be clinically useful for localization of lesions in the corticospinal tract; the primary lesion can be localized whether above or below the pyramidal decussation.

P15 in tibial nerve SEPs as an example of the junctional potential

Tibial nerve stimulation at the ankle elicited a stationary, dipolar potential P15/N15 over the buttock with a reference electrode at the contralateral greater trochanter (GTc). P15 was distributed in the rostral and contralateral region and N15 in the caudal and ipsilateral region. The derivation from the contralateral iliac crest to the ipsilateral greater trochanter (ICc-GTi) registered a large P15 (= P15-N15) potential which was well free from artifacts. The Cz'-contralateral knee lead, which had been employed in previous studies, registered a smaller P15 of poor quality. Sequential bipolar recording along the course of the sciatic nerve indicated that P15 was generated around the greater sciatic foramen. Comparison with a simulation study suggested that P15 is a junctional potential which is generated when the sciatic nerve enters the bone at the greater sciatic foramen. P15 is expected to be a useful tool to evaluate the proximal segment of the tibial nerve.

Lidocaine unmasks silent demyelinative lesions in multiple sclerosis

Blockage of a small number of sodium channels may prevent impulse conduction in some demyelinated segments of nerve fibers with low safety factors, thereby unmasking subclinical demyelinative lesions. On the basis of this hypothesis, lidocaine, a sodium channel blocker, was administered intravenously to 28 MS patients and to 19 normal subjects and seven patients with nondemyelinating diseases. As predicted, lidocaine (mean plasma level, 2.7 micrograms/ml) elicited reversible subclinical symptoms in 23 of the MS patients, but it had not effect on the control subjects. We made a quantitative study of the visual functions (visual acuity, color vision, visual evoked potential [VEP]) that were impaired in 15 MS patients. Of the 23 affected eyes, nine showed normal VEPs, indicative of the test's sensitivity to focal lesions. This test should be useful in the diagnosis of MS and in the evaluation of the subclinical activity of MS as well.

Developmental changes of fucosylated glycoconjugates in rabbit dorsal root ganglia

Developmental changes of the fucosylated glycoconjugates in the dorsal root ganglia (DRG) of the rabbit were investigated histochemically using anti-fucosyl GM1 antibody and Ulex europaeus agglutinin 1 (UEA-1) lectin. Neither anti-fucosyl GM1 antibody nor UEA-1 lectin bound to the neural tubes or to the neural crest on embryonic day 14 (E14). Anti-fucosyl GM1 antibody binds diffusely to the DRG of E25. Large neurons unreactive with anti-fucosyl GM1 antibody appeared at 1 month and increased within 6 months after birth. Schwann cells immunoreactive with anti-fucosyl GM1 antibody came to be limited to the satellite cells surrounding the positive neurons. No staining with UEA-1 lectin was observed in the DRG of E25. Some small neurons became reactive with UEA-1 lectin within 1 month and remained to be so at 6 months after birth. Schwann cells including satellite cells were unreactive with this lectin. Since fucosyl GM1 was detected in the lipid fraction of DRGs from 1-month-old and 6-month-old rabbits, fucosyl GM1 itself should be the antigen molecule recognized by the anti-fucosyl GM1 antibody. Further study is necessary to elucidate the association between these developmental changes of the fucosylated glycoconjugates in DRG and their possible functional roles.

Origin of the widespread N18 in median nerve SEP

The widespread N18 potential in median nerve SEP was studied in normal subjects and in patients with high cervical, brain-stem and thalamic lesions who had profound disturbances of deep sensation. N18 was well identified in the HSi-CV2 derivation in every normal subject as a broad elevation from the baseline lasting about 20 msec. The cortical N20 was absent in all patients. N18 was absent in a patient with a dorsal column lesion at C1-2 level. The amplitude and configuration of N18 were normal in all other patients with brain-stem and thalamic lesions, including a patient with a lesion at the ponto-medullary junction. The sagittal distribution of N18 was studied in a patient with a thalamic lesion and an oblique distribution with the maximum region between Cz and nasion was demonstrated. The present results indicate that at least the greater part of N18 is generated at the caudal most brain-stem or through branches from this level. Taking previous animal and intraoperative studies into consideration, we think it most probable that the main part of N18 corresponds to the ventro-rostral negative pole of the dipolar potential generated at the cuneate nucleus by the primary afferent depolarization of presynaptic terminals of dorsal column fibers.

[Gene analysis of Japanese patients with familial amyloidotic polyneuropathy type IV]

Familial amyloidotic polyneuropathy type IV (FAP IV) is clinically characterized by slowly progressive cranial neuropathy and corneal lattice dystrophy. More than 300 cases were clustered in the Finnish population. Recent biochemical studies have demonstrated that the amyloid fibril protein in FAP IV is related to Asn-187 variant gelsolin, and the corresponding missense mutation, a G to A substitution at nucleotide 654 of plasma gelsolin cDNA, cosegregates with the disease phenotype in Finnish families. Here we analyzed the gelsolin gene of the Japanese family with FAP IV which we described as the first Japanese case. Direct sequence analysis of PCR-amplified DNA fragments spanning the codon 187 of plasma gelsolin cDNA from the 2 affected family members demonstrated a single base substitution, G to A at nucleotide 654, which is identical to the mutation of Finnish FAP IV. Restriction analysis using a modified PCR revealed that three unaffected family members and three unrelated healthy controls were homozygous for the normal allele, whereas the seven affected family members were heterozygous for the normal and the mutated alleles. This indicates the cosegregation of the mutation with the disease phenotype in this Japanese family, suggesting that the mutation causes the FAP IV phenotype regardless of ethnic background.

[Familial amyloidotic polyneuropathy type IV (Finnish type)--the first description of a large kindred in Japan]

Familial amyloidotic polyneuropathy type IV, one of the hereditary systemic amyloidoses with an autosomal dominant trait, is clinically characterized by cranial neuropathy and corneal lattice dystrophy. Recent biochemical studies have indicated that the amyloid fibril protein in FAP IV is related to gelsolin, an actin-modulating protein. Cases were clustered in the Finnish population and only a few cases have been reported from other populations. Here we described a large kindred with FAP IV as the first report in Japan. This family comprises 42 members in three generations with 14 affected individuals. We examined 7 patients at the age ranging from 43 to 80 years. All cases have corneal lattice dystrophy type II. The disease begins with slowly progressive facial weakness in the fifth or sixth decade of life and consequently the V, XII, IX and X cranial nerves become involved. Peripheral neuropathy of the extremities remained mild until late of life. Microscopy of skin biopsy samples showed deposits of amyloid around the eccrine glands, sebaceous glands, epidermal-dermal junction and blood vessel walls. Immunohistochemistry of the skin revealed the immunopositive material against a monoclonal antibody to gelsolin in the amyloid deposits. Molecular analysis of the gelsolin gene is now in progress.

Immunohistochemical study of kuru plaques using antibodies against synthetic prion protein peptides

Prion protein (PrP) is a protein closely associated with the transmission of scrapie and Creutzfeldt-Jakob disease (CJD). Kuru plaques are composed of this protein. PrP33-35 is converted to protease-resistant PrP27-30 by proteinase K digestion. It has not yet been determined which of these PrPs is present in kuru plaques in vivo. Accordingly we synthesized two peptides (peptide-N and peptide-M) that, respectively, corresponded to the protease-sensitive and protease-resistant portions of PrP33-35, based on the amino acid sequence deduced from human PrP cDNA. These two synthetic peptides were used to immunize rabbits and produce antisera (anti-N and anti-M). Both antisera stained kuru plaques in a patient with Gerstmann-Sträussler syndrome and one with CJD. Peptide-N has an amino acid sequence which does not exist in PrP27-30. Staining of kuru plaques by the antiserum against peptide-N indicated that the entire molecule, including the N-terminal portion of PrP33-35, was deposited in the kuru plaques.

[Wallenberg's syndrome due to vertebral artery dissection following minimal neck injury--report of two cases]

We described two cases of the lateral medullary syndrome (Wallenberg's syndrome) due to vertebral artery dissection following minimal neck injuries. The first case was a 45-year-old man, who hit his head and often rotated his head because of posterior neck discomfort. Two years after the injury, he suffered from sudden sharp neck pain, nausea, and vertigo, which was followed by left hand numbness and difficulty in walking due to the right lateral medullary syndrome. Angiography showed right vertebral artery dissection at the fourth segment. The second case, a 48-year-old man, suffered from neck pain immediately after he hyperextended his neck for painting a wall. Within several hours, he experienced left hand numbness and difficulty in walking due to the lateral medullary syndrome. Angiography showed a saccular aneurysm and dissection of the right vertebral artery at the fourth segment. In both cases, minor traumas were thought to be the causes of vertebral artery dissection. We surveyed previously reported 84 cases (men: 50, women: 34) of the vertebral artery dissection due to minor traumas. Seventy per cent of patients were in their third or fourth decade of life. The main causes of trauma preceding the dissection were neck manipulation especially chiropractics (52%). The third segment was most vulnerable. Delay in onset following neck trauma could be more than a week, but in most cases the delay was less than 24 hours. Cervical rotation and extension were thought to precipitate dissection.

Paired helical filaments in astrocytes: electron microscopy and immunohistochemistry in a case of atypical Alzheimer's disease

A 54-year-old man who had cerebellar ataxia and pseudobulbar palsy at the age of 29 years, and soon developed dementia, myoclonus and convulsions, died after about 20 years in a vegetative state. Histological examination of the extensively atrophic and devastated brain (680 g) revealed the almost total loss of cerebral cortical neurons associated with numerous beta-protein amyloid plaques, many extracellular tangles and a large number of hypertrophic astrocytes, and prominent amyloid angiopathy. The astrocytes were frequently immunopositive for anti-human tau antibody (anti-htau) and anti-ubiquitin antibody (anti-ubi). Double immunostaining with anti-htau and anti-glial fibrillary acidic protein (GFAP) antibody clearly demonstrated htau-positive domains within the GFAP-positive perikarya/and processes of several astrocytes. Electron microscopy of the hippocampal CA1, which was completely devoid of pyramidal neurons, revealed, in astrocytes, abnormal filaments indistinguishable from the paired helical filaments (PHFs) seen in neurons. On immunoelectron microscopy, the filaments were observed to be labeled with anti-htau and anti-ubi, exhibiting the same immunohistochemical features as neuronal PHFs. This is the first demonstration of clearly constricted and both tau- and ubiquitin-positive PHFs in astrocytes, indicating that, in some special conditions like in our case, processes similar to those that attack neurons also affect astrocytes and ultimately make the latter form PHFs.

Nation-wide collaborative study on the long-term effects of bromocriptine in the treatment of parkinsonian patients: analysis on the maintenance and the change of the original mode of treatment

A nation-wide collaborative study to evaluate the long-term effects of bromocriptine in patients with Parkinson's disease was completed as described in the accompanying paper. The present study analysed the same data by paying attention to a group of patients who maintained the original mode of therapy and to a group of patients who changed the mode of treatment by adding levodopa or bromocriptine to the original drug. Surprisingly, 48 among 286 patients in a group of bromocriptine monotherapy maintained the original mode of therapy. This group has particular features of a short duration of illness and a low grade of Hoehn-Yahr's scale. It is noteworthy that this group of patients did not show wearing-off phenomenon. The effects of additional bromocriptine to levodopa for a 5-year period were analysed by comparing two groups of combination therapy and levodopa alone therapy maintained for 5 years, with 106 and 92 patients, respectively. Results were essentially the same as those obtained from the accompanying paper, i.e., in general, treatment by combination with bromocriptine may be more suitable than treatment by levodopa alone. In order to find the best timing of the combination of levodopa and bromocriptine, results of 3 groups were compared, i.e. a group of patients who started with bromocriptine alone and later added with levodopa (82 patients), a group of patients who maintained the combination for 5 years (106 patients) and a group of patients who started with levodopa alone and later added bromocriptine (27 patients). The best results were obtained in the group of 5-year combination.(ABSTRACT TRUNCATED AT 250 WORDS)

Accumulation of amyloid precursor protein and beta-protein immunoreactivities in axons injured by cerebral infarct

To determine the distribution of amyloid precursor protein (APP), monoclonal antibodies against APP45-62 (APP1-28-9) and beta1-17 (4A18 and 4A61) were produced. In the sections of Alzheimer's disease (AD) brain, APP1-28-9 was reactive with neurites around senile plaques and a few neurons but not with amyloid cores. This antibody also immunostained the axons in the ischemic lesions of brain tissues from cases with cerebral infarct. 4A18 and 4A61 were reactive with amyloid plaques but not with neurites and neurons. The latter two antibodies also immunostained axons in ischemic lesions. These findings suggest that APP, transported by the fast axonal flows, accumulated in the injured axons in the central nervous system. The beta immunoreactivity appearing in those axons may provide a clue to the mechanism of amyloidogenesis.

[An autopsy case of Degos disease with neurological symptoms--neuropathological observations and increased platelet aggregation]

We reported clinical and neuropathological observations of a 41-year-old man with Degos disease. He first noted painless skin lesions over the upper extremities in January, 1982. Three years later he was diagnosed as Degos disease by skin biopsy, and treatment with aspirin was started. In September, 1985, he complained of paresthesia on his right arm, followed by a series of new neurological manifestations suggesting multifocal spinal cord lesions. On October 28, examination of admission showed papules with central umblication over the whole body except the head, face, palms, soles and scrotum. Neurological examination revealed no weakness, diminished right biceps reflex, exaggerated patellar reflexes and Achilles reflexes, left extensor plantar reflex, hypesthesia and hypalgesia to the level of Th8, mild left spastic gait, and retention of urine. In November, he had paraparesis, loss of vibration sense of lower extremities, hypesthesia and hypalgesia to the level of TH4, and weakness of right upper extremity. In December, he showed tetraplegia, left-sided facial palsy, and hypesthesia and hypalgesia to the level of C5. In January, 1986, he showed right facial palsy, left facial hypesthesia, pseudobulbar palsy. In February, he had bilateral abducens nerve palsy and hiccups. On February 18, he died of intracranial hemorrhages. He had episodic abdominal pain several times during admission. His condition deteriorated progressively in four months after the first manifestation of neurological symptoms, despite the therapy with heparin, urokinase, ticlopidine, dipyridamole, and prednisolone. Laboratory studies showed gradual increase of CSF proteins (from 156 mg/dl to 602 mg/dl) and extremely increased platelet aggregation.(ABSTRACT TRUNCATED AT 250 WORDS)

Nation-wide collaborative study on the long-term effects of bromocriptine in the treatment of parkinsonian patients. Final report

Final results of the 5-year multicentric collaborative study on the long-term effects of bromocriptine in the patients with Parkinson's disease are reported. This prospective study started in May 1985 in order to see whether the early combination therapy with bromocriptine and levodopa is really superior to the levodopa monotherapy with regard to the late side effects of levodopa in the treatment of parkinsonian patients. Another project of the study was to see the therapeutic efficacy of bromocriptine monotherapy without concomitant use of levodopa. For these purposes, a total of 702 patients with Parkinson's disease were enrolled into three groups: Group 1 (n = 286) with bromocriptine monotherapy, Group 2A (n = 216) with early combination of bromocriptine and levodopa, and Group 2B (n = 200) with levodopa alone. At the end of the 5-year study, 48 patients in Group 1 (16.8%) were still continuing bromocriptine monotherapy with satisfactorily good therapeutic effects. About half (49.1%) of the Group 2A patients remained on the combined therapy, and the comparable number of the Group 2B patients (46.0%) were also kept on the initial mode of therapy, while 13.5% of the latter group with levodopa monotherapy needed bromocriptine to be added in order to assure the good therapeutic effects. Moreover, significant differences were seen between group 2A and Group 2B with regard to the incidence of wearing-off phenomenon and dyskinesias. Disappearance rate of dyskinesias which were present at the time of enrollment was significantly higher in Group 2A than in Group 2B. No significant difference was noted as to the incidence of untoward symptoms and the death rate among all three therapeutic groups. These results support the view that the early combination of bromocriptine with levodopa is superior to levodopa alone in the treatment of Parkinson's disease.

[Neuropathology of Onuf's nucleus]

Onuf's nucleus is a small motoneuron group in S2 anterior horn, which was described by Onufrowicz in 1900. He suggested that the motoneurons in the nucleus innervated striated muscles involved in election and ejaculation. The nucleus is readily shown by the K-B stain on account of its pale staining background which is sharply demarcated from the surrounding network of fine myelinated fibers. However, neuropathological descriptions of the nucleus are very rare. Pons-Tortella et al reported the sparing of this nucleus in acute anterior poliomyelitis. In 1977. We reported that Onuf's nucleus were well preserved in cases with ALS, in which the function of bladder and rectal sphincters is often intact until the latest stage of the illness. On the control , Shy-Drager syndrome showed severe degeneration of Onuf's nucleus. The patients with Shy-Drager syndrome showed clinically evident urinary and/or fecal incontinence. Combination of these clinical and pathological findings led to conclusion that Onuf's nucleus innervates the striated muscles of the sphincters. In 1990, Iwatsubo et al studied corticofugal projections to the motoneurons with Nauta-Gygax's technique in a patient with cerebral infarction. They verified that the oculomotor and abducens nuclei and Onuf's nucleus do not receive direct cortical projections. These motoneurons are characteristically spared in ALS. For the studies on ALS, it is important to know what differences between Onuf's nucleus and other motoneuron groups in anterior horn are biochemically and physiologically.