[Effect of number of syllables in word repetition]

We report a case of non-fluent conduction aphasia. The patient was a 59-year-old right-handed male. He suffered from aphasia after a left internal carotid artery occlusion. MRI study revealed subcortical lesions in the left inferior frontal gyrus and cortical lesion in the anterior part of the left insular gyrus and the left postcentral gyrus. The patient showed good comprehension of words and daily conversation but had a common difficulty in the following tasks; naming of pictures, repetition of words, reading of kanji and kana letters. In these tasks, the phonological output of the patient contained many literal paraphasias and there was a tendency that errors appeared more in the posterior portion of a target word. We analyzed the position of errors in the target word on word repetition tasks. The result confirmed the above observation. We speculate that the length of a target word may have played a critical rote in this patient's repetition capability.

Dinucleotide repeat polymorphism in the third intron of the NRAMP2/DMT1 gene

Nramp1 (natural resistance-associated macrophage protein 1), encoding a polytropic integral membrane protein, was isolated as a candidate of the mouse Lsh/Ity/Bcg locus, which regulates macrophage activation for anti-microbial activity against intracellular pathogens. The NRAMP2 gene was cloned from human genome as a homologue of NRAMP1. We found a polymorphic dinucleotide repeat in the third intron of the NRAMP2 gene. This polymorphism will be a useful genetic marker to study disease associated with susceptibility to infection with intracellular pathogens.

Functional analysis of the human NRAMP family expressed in fission yeast

The Bcg/Ity/Lsh locus in the mouse genome regulates macrophage activation for antimicrobial activity against intracellular pathogens, and the positional cloning of this locus identified the Nramp1 (natural resistance-associated macrophage protein) gene. Nramp2 was initially isolated as a homologue of Nramp1. Recently, the rat divalent metal transporter DMT1 was identified electrophysiologically, and was found to be an isoform of Nramp2, a mutation which was subsequently identified in rats suffering from hereditary iron-deficiency anaemia. Despite the 64% amino acid sequence identity of Nramp1 and Nramp2, no divalent metal transport activity has yet been detected from Nramp1, and the function of Nramp1 on the molecular level is still unclear. To investigate the divalent metal transport activity of NRAMP molecules, we constructed four chimeric NRAMP genes by swapping the domains of human NRAMP1 and NRAMP2 with each other. The functional characteristics of wild-type NRAMP1, NRAMP2 and their chimeras were determined by expression in the divalent metal transporter-disrupted strain of fission yeast, pdt1Delta, and we analysed the divalent metal transport activity by complementation of the EGTA- and pH-sensitive phenotype of pdt1Delta. Replacement of the N-terminal cytoplasmic domain of NRAMP2 with the NRAMP1 counterpart resulted in inactive chimeras, indicating that the functional difference between NRAMP1 and NRAMP2 is located in this region. However, results obtained with the reverse construct and other chimeras indicated that these regions are not solely responsible for the differences in EGTA- and pH-sensitivity of NRAMP1 and NRAMP2. These findings indicate that NRAMP1 itself cannot represent the divalent metal transport activity in S. pombe and the additional protein segments of the molecules located elsewhere in NRAMP1 are also functionally distinct from their NRAMP2 counterparts.

A new mouse model of spontaneous diabetes derived from ddY strain

By the selective breeding of obese male mice of the ddY strain and using indices of the heavy body weight and appearance of urinary glucose, we established two inbred strains in 1992: one with obesity and urinary glucose (Tsumura, Suzuki, Obese Diabetes: TSOD) and the other without them (Tsumura, Suzuki, Non Obesity: TSNO). The male TSOD mice constantly showed signs of obesity and urinary glucose with increases in food and water intake, body weight and some fat weight. The body mass index (BMI) clearly showed moderate obesity. Increases in the levels of diabetic blood parameters (glucose, insulin and lipids) were also found in males, in which the levels of blood glucose and insulin were high to the ages past the growth peak. In the histological studies, pancreatic islets of the TSOD males were found hypertrophic without any signs of insulitis or fibrous formation. Among these diabetic characteristics, some of which were similar to the reported models of non-insulin-dependent diabetes mellitus (NIDDM), the stable appearances of the hyperglycemia, the hyperinsulinemia and the hypertrophy of pancreatic islets to the ages past the growth peak were the prominent features. In these respect the TSOD mouse may be a useful model for researching the mechanisms of human diabetes and its complications.

Diffusion-weighted magnetic resonance imaging: detection of ischemic injury 39 minutes after onset in a stroke patient

A neurologist witnessed the in-hospital onset of an ischemic stroke in a 71-year-old right-handed male who suddenly developed global aphasia and right hemiplegia. Diffusion-weighted magnetic resonance imaging (DWI) 39 minutes after the ictus demonstrated high signals in the left internal carotid artery territory. T1- and T2-weighted images failed to detect this change. Magnetic resonance angiography showed occlusions in branches of the left anterior and middle cerebral arteries and an atheromatous stenotic lesion in the ipsilateral proximal internal carotid artery. The patient was treated with intravenous heparin and low molecular dextran solution. Repeated magnetic resonance imagings identified an infarction slightly smaller than the abnormality demonstrated by the initial DWI. DWI detects hyperacute ischemic injury within 1 hour of symptom onset in human ischemic stroke.

Risk factors for silent cerebral infarcts in subcortical white matter and basal ganglia

BACKGROUND AND PURPOSE

The purpose of this study was to clarify whether the relevant risk factors for silent cerebral infarcts (SCIs) in subcortical white matter (WM) are different from those in the basal ganglia (BG).

METHODS

Subjects of this study were 219 adults without a history of stroke or transient ischemic attack and without any abnormality on a neurological examination who consecutively visited the neurology service in our hospital between January 1994 and November 1997 requesting medical evaluation for possible cerebrovascular diseases. Subjects included 141 men and 78 women ranging in age from 33 to 83 years (mean+/-SD, 63.2+/-9.5 years). We performed brain MRIs and cervical/cranial MR angiographies on all subjects. In this study, SCI was defined as a focal lesion >5 mm in diameter that was prolonged on both T2-weighted and proton density images.

RESULTS

SCIs in the WM and/or BG were detected in 88 (40.2%) of the 219 subjects. No SCI >15 mm was observed in this series. Fifty of the subjects had SCIs only in the WM, 32 subjects had SCIs in both the WM and BG, and 6 subjects had SCIs only in the BG. Thus, 82 (93.2%) of 88 subjects with SCIs had lesions in the WM. Most subjects with SCIs in the BG also had SCIs in the WM. Multiple logistic regression analyses revealed that age, female sex, and hypertension were significant and independent predictors of SCIs in the WM, and that age, a history of ischemic heart disease, and carotid artery stenosis were significant and independent predictors of SCIs in the BG.

CONCLUSIONS

The present study indicated that the relevant risk factors for SCIs in the WM and those for SCI in the BG were different. Our results suggest that SCIs are prone to first appear in the WM in association with aging and hypertension, and the additional appearance of SCIs in the BG predicts a progression of generalized atherosclerosis that is manifested in the carotid and coronary arteries.

Human natural resistance-associated macrophage protein 2: gene cloning and protein identification

The Lsh/Ity/Bcg locus in the mouse genome regulates macrophage activation for antimicrobial activity against intracellular pathogens, and mouse Nramp1 (natural resistance-associated macrophage protein) gene was isolated as its candidate. The human NRAMP1 gene was subsequently isolated and its gene product was identified in macrophage/monocyte cells. Recently, a second Nramp gene, Nramp2, was found in mouse and human genomes. In the present study, we report the cloning and characterization of the human NRAMP2 gene, which is approximately 42 kb in length, containing 16 exons. The transcription start site was determined by 5'-RACE method, and the promoter was located between -246 bp to 145 bp in a region relative to the transcription start site, able to drive the luciferase reporter gene in HeLa cells. We also raised a polyclonal antibody against the glutathione S-transferase fusion protein containing the NH2-terminal 86 amino acids of human NRAMP2. The protein product of the human NRAMP2 gene is apparently present in human cultured cell lines as a 64 kDa protein recognized by this antibody, which is consistent with the molecular mass deduced from the human NRAMP2 cDNA.

Frequency and clinical correlates of occlusive lesions of cerebral arteries in Japanese patients without stroke. Evaluation by MR angiography

To determine the frequency and clinical correlates of intra- and extracranial arterial occlusive lesions in a stroke-free population, we studied cerebral arteries in 156 subjects with no evidence of stroke who presented at a neurologic clinic with concerns about a possible stroke (104 males ranging in age from 37 to 83 years, with a mean age of 63.0) by using MR angiographies (MRAs). According to a validated rating scheme of MRAs for occlusive lesions, the degree of stenoses in the cervical portion of the carotid artery and of the intracranial arteries including the intracranial portion of the internal carotid artery, the middle cerebral artery stem, and the basilar artery were evaluated. Stenoses (>25% narrowing in diameter) were found in 18 patients (11.5%) in the cervical carotid artery, and in 23 patients (14.7%) in the intracranial arteries. Multiple logistic regression analysis showed that age and hyperlipidemia were significant and independent predictors for cervical carotid artery stenoses, and that age and hypertension were predictors for intracranial artery stenoses. Our data based on this special cohort of stroke-free patients suggested that the risk factors for extra- and intracranial artery lesions were different, and that MRA is possibly efficient in those patients in whom cerebral artery occlusive lesions may be suspected. e.g. in hyperlipidemic or hypertensive elderly. Larger population-based studies are needed to confirm these results.

Observation of composition in surface monolayers by X-ray scattering spectra caused by crystal truncation and interferences

X-ray crystal-truncation-rod (CTR) scattering measurements using synchrotron radiation and an imaging plate can reveal the composition of a surface monolayer. Even when the composition is changed in only one atomic layer on the top surface, the X-ray CTR spectrum can change due to the differences in composition. X-ray CTR spectra are greatly enhanced by X-ray interference when a sample is designed properly. In this paper, it is shown by theoretical calculations and experiments for AlAs/GaAs samples grown by MBE that a 1 ML (monolayer)-thick AlAs layer embedded under 10 ML below the surface can enhance the modulation of an X-ray CTR spectrum.

Local structure study of dilute Er in III-V semiconductors by fluorescence EXAFS

For understanding the luminescence of Er atoms in III-V semiconductors, OMVPE-grown InP doped with Er has been investigated by fluorescence EXAFS (extended X-ray absorption fine structure) in order to study the local structure around Er atoms. The local structures around the Er atoms doped in InP, with doping as dilute as 3 x 10(12) Er atoms in a 1.5 mm x 1.0 mm spot, were successfully measured by fluorescence EXAFS. The EXAFS analysis revealed that the Er atoms doped in InP above 853 K (which showed low luminescence) formed the rock-salt-structure ErP, while the Er atoms doped in InP below 823 K (which showed high luminescence) substituted on the In site of InP. The dependence of the local structure on growth temperature was observed for the samples doped with 3 x 10(12) atoms and 1.2 x 10(13) atoms of Er.

Isolation and characterization of an invertase and its repressor genes from Schizosaccharomyces pombe

PCR was used to isolate an invertase homolog gene from the fission yeast Schizosaccharomyces pombe. The cloned inv1(+) gene encodes a protein of 581 amino acids with 16 potential asparagine-linked glycosylation sites, and has 39% and 38% identity to the Schwanniomyces occidentalis and Saccharomyces cerevisiae SUC2 invertases. When the inv1(+) gene was disrupted, S. pombe strains lacked detectable invertase activity. This result showed that the inv1(+) gene encodes only one active invertase in S. pombe cells. The transcription of inv1(+) is repressed in the presence of glucose. The transcription of inv1(+) was not affected in cyr1Delta strain which lacks adenylate cyclase activity, unlike transcription of S. pombe fbp1(+) gene. We have identified an S. pombe gene (scr1(+)) that encodes a homolog of the Aspergillus nidulans CREA which is required for glucose repression of the glyconeogenic pathway. Although the deletion of scr1(+) did not influence the transcription of fbp1(+) gene, glucose repression of the inv1(+) gene was severely affected. These results showed that glucose repression of inv1(+) gene is dependent on scr1(+) gene, and S. pombe cAMP signalling pathway may not be essential for glucose repression of inv1(+) gene.

[The role of the right hemisphere on recovery from Wernicke's aphasia]

We report a rare case of severe Wernicke's aphasia who showed a rapid and surprisingly good recovery despite of a large infarct involving the left posterior language area. A 68-year-old right-handed woman without a family history of left-handedness developed a severe comprehension difficulty and paraphasic output following a large infarct in the left posterior temporoparietal region. However, in 6 weeks, naming, comprehension, and repetition of words became almost normal. Spontaneous speech also became almost normal, although comprehension and repetition of sentences remained slightly impaired. The lesion size remained unchanged. A dichotic listening test 4 months after the onset showed clear left ear superiority. We speculate from these observations that the dormant language function in the right hemisphere might have played a role for rapid and good recovery of this case.

High frequency of unruptured intracranial aneurysms in female patients with ischaemic heart disease

OBJECTIVES

Concurrence of coronary atherosclerotic lesions and intracranial aneurysms has been pointed out in several postmortem and clinical studies. However, the relative risk for intracranial aneurysms in patients with ischaemic heart disease remains uncertain. The aim of this study is to elucidate clinically whether ischaemic heart disease is a risk factor for intracranial aneurysms.

METHODS

Between October 1993 and May 1995, 84 patients with ischaemic heart disease with angiographically established coronary artery stenoses who had no history of stroke (ischaemic heart disease group; men:women=58:26, mean (SD) age=61.1 (9.6) years) and 200 age matched subjects with minor neurological disorders who had no history of ischaemic heart disease (control group; men:women=117:83, mean (SD) age=62.0 (9.2) years) were screened with magnetic resonance angiography (MRA) for the presence of unruptured intracranial aneurysms. For all MRA positive patients, selective angiography was then undertaken.

RESULTS

In the ischaemic heart disease group, the frequency of unruptured intracranial aneurysms established angiographically was 3.4% for men and 15.4% for women, compared with 2.6% and 3.6% respectively in the control group. Multiple logistic regression analyses disclosed that ischaemic heart disease was a significant and independent predictor for intracranial aneurysms in women.

CONCLUSIONS

These results suggest that in women ischaemic heart disease is a risk factor for intracranial aneurysms. Coexistence of intracranial aneurysms should be suspected in women patients with ischaemic heart disease.

Enzymatic synthesis of a neoglycoconjugate by transglycosylation with Arthrobacter endo-beta-N-acetylglucosaminidase: a substrate for colorimetric detection of endo-beta-N-acetylglucosaminidase activity

The transglycosylation activity of endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae was used for the enzymatic synthesis of a novel oligosaccharide, Man6GlcNAc-p-nitrophenyl-alpha-D-glucose (Man6GlcNAc-Glc-pNP). The reaction was efficiently induced in aqueous solution containing dimethyl sulfoxide. In the medium containing 20% (v/v) dimethyl sulfoxide with 0.1 M Glc-pNP as an acceptor, the transglycosylation attained yields of 75% by high-performance anion-exchange chromatography. The structure of Man6GlcNAc-Glc-pNP was confirmed by ion mass spectrometry and 400 MHz 1H NMR spectrometry. Various endo-beta-N-acetylglucosaminidases hydrolyzed this oligosaccharide and Man6GlcNAc and Glc-pNP were released from the oligosaccharide by endo-beta-N-acetylglucosaminidase digestion. We have established a new procedure for the colorimetric detection of endo-beta-N-acetylglucosaminidase activity using Man6Glc-NAc-Glc-pNP, which is simple as that for other exoglycosidase assays with pNP-glycosides as substrates.

Spontaneous dural carotid cavernous sinus fistula presenting isolated ophthalmoplegia: evaluation with MR angiography

We describe three patients with spontaneous dural carotid cavernous sinus fistula presenting an isolated ophthalmoplegia where magnetic resonance angiography demonstrated abnormal flow-related enhancements in the cavernous sinus with extension into the inferior petrosal sinus. Magnetic resonance angiography is of value in evaluation of patients with isolated ophthalmoplegia.

[Occlusive lesions of carotid and intracranial arteries in patients with symptomatic lacunar infarction--evaluation by MR angiography]

The purpose of this study is to elucidate the prevalence and degree of occlusive lesions of carotid and intracranial arteries in patients with symptomatic lacunar infarction. We performed carotid and intracranial MR angiography, and T2-weighted MRI on 65 patients with symptomatic lacunar infarction. Stenosis of more than 25% narrowing of the diameter was found in 12 patients (18.5%) in the extracranial carotid arteries and in 14 patients (21.5%) in the intracranial arteries. Most of the stenotic lesions were mild. Multiple logistic regression analysis showed that age was significant and independent predictor for carotid artery stenosis, and that diabetes mellitus was predictor for intracranial artery stenosis. The incidence of intracranial artery stenosis was statistically higher in patients with asymptomatic lacunar infarctions in subcortical white matter area on T2-weighted MRI than in patients without such lesions. Coexistence of carotid artery stenosis should be suspected in aged patients with symptomatic lacunar infarction, and the possibility of intracranial artery stenosis should be considered in patients with diabetes mellitus or asymptomatic lacunar infarctions in subcortical white matter area.

Complete nucleotide sequence of human NRAMP2 cDNA

The mouse Lsh/Ity/Bcg locus regulates macrophage activation for antimicrobial activity against intracellular pathogens, and the Nramp1 gene was isolated as its candidate. In the present study, a full length cDNA for human NRAMP2 has been isolated and characterized. Nucleotide sequence analysis reveals that the cDNA, 4142 bp in length, coded for a protein of 561 amino acid residues with a molecular weight mass of 61,456. Predicted amino acid sequence analysis of the NRAMP2 molecule indicates that NRAMP1 and NRAMP2 sequences share 64% identical residues overall, whereas only 21% at the NH2-terminal cytoplasmic domain, where the NRAMP1 molecule was associated with microtubules, was found to be identical. This suggests that the NH2-terminal region of the NRAMP2 molecule may have a particular function, different from that of the NRAMP1 molecule.

Vacuolar protein sorting in fission yeast: cloning, biosynthesis, transport, and processing of carboxypeptidase Y from Schizosaccharomyces pombe

PCR was used to isolate a carboxypeptidase Y (CPY) homolog gene from the fission yeast Schizosaccharomyces pombe. The cloned S. pombe cpy1+ gene has a single open reading frame, which encodes 950 amino acids with one potential N-glycosylation site. It appears to be synthesized as an inactive pre-pro protein that likely undergoes processing following translocation into appropriate intracellular organelles. The C-terminal mature region is highly conserved in other serine carboxypeptidases. In contrast, the N-terminal pro region containing the vacuolar sorting signal in CPY from Saccharomyces cerevisiae shows fewer identical residues. The pro region contains two unusual repeating sequences; repeating sequence I consists of seven contiguous repeating segments of 13 amino acids each, and repeating sequence II consists of seven contiguous repeating segments of 9 amino acids each. Pulse-chase radiolabeling analysis revealed that Cpy1p was initially synthesized in a 110-kDa pro-precursor form and via the 51-kDa single-polypeptide-chain intermediate form which has had its pro segment removed is finally converted to a heterodimer, the mature form, which is detected as a 32-kDa protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. Like S. cerevisiae CPY, S. pombe Cpy1p does not require the N-linked oligosaccharide moiety for vacuolar delivery. To investigate the vacuolar sorting signal of S. pombe Cpy1p, we have constructed cpy1+-SUC2 gene fusions that direct the synthesis of hybrid proteins consisting of N-terminal segments of various lengths of S. pombe Cpy1p fused to the secreted enzyme S. cerevisiae invertase. The N-terminal 478 amino acids of Cpy1 are sufficient to direct delivery of a Cpy1-Inv hybrid protein to the vacuole. These results showed that the pro peptide of Cpy1 contains the putative vacuolar sorting signal.

Eye opening reflex triggered by flexion of an arm: a manifestation of decerebrate response in diffuse bilateral hemispheric damage

Images

["Forced mouth opening reaction" associated with corticobasal degeneration]

Corticobasal degeneration (CBD) is a slowly progressive disorder characterized by an asymmetrical akinetic-rigid syndrome, supranuclear ophthalmoplegia, dystonia, often accompanied by involuntary movements, particularly myoclonus, and associated with lateralized cortical signs such as alien limb behavior and apraxia. Computerized tomography demonstrates asymmetrical frontoparietal cortical atrophy in the later stages of the illness. Neuropathological examination reveals neuronal loss, gliosis and swollen achromatic neurons within the frontal and temporal cortices, and the substantia nigra. We discuss here a unique phenomenon not described so far in three patients with clinical features of CBD, one with subsequent autopsy observations. When awake, they all showed a common behavior, their mouth opened constantly and immediately, when a tongue-depresser was approached in front of it by the examiner. In two of them, their mouth also opened when its corner was stroked by a tongue-depressor. They could not control these phenomena at all, even they were asked not to open their mouth. We would like to call these phenomena "forced mouth opening reactions" because they were uncontrollable voluntarily. They may be divided into two groups, i.e. visual and tactile "forced mouth opening reactions". In all the patients the neurological, neuro-imaging and neuropathological data showed that the frontal lobes were damaged. Additionally, they had some frontal lobe release signs such as forced grasping, forced groping, or alien limb sign. We would like to apply the mechanism for these release signs to the "forced mouth opening reactions". Thus, we speculate that the frontal lobe contains a higher motor control mechanism for normal mouth opening movement, and the "forced mouth opening reactions" result from impairment of this control.

Inhibition of octapeptide N-myristoylation by acyl amino acids and acyl alkanolamines

Several acyl amino acids and acyl alkanolamines were prepared and screened for their inhibition of octapeptide N-myristoylation and HIV-1 replication in MT-4 cells. Of the 62 acyl derivatives tested, N-myristoyl-O-caproyl-L-serine, N-myristoyl-O-caproyl-D-serine and N-decanoyl-O-myristoyl-L-serine were found to be uncompetitive inhibitors of N-myristoylation, but did not prevent HIV-induced cytopathicity in MT-4 cells. However, other acyl derivatives such as N-3-hydroxymyristoyl ethanolamine, N-3-hydroxymyristoyl-D-serine and N-myristoyl-L-cysteine, which did not inhibit N-myristoylation, suppressed the cytopathicity in the infected cells. The acyl derivatives described here may serve as lead compounds for antiviral agents.