[Biological features determining the chemosensitivity of gastric cancer]

We analysed the relationship between several biological properties of gastric cancers and their chemosensitivity determined by MTT assay. Higher chemosensitivity was associated with poor differentiation, aneuploidy, and higher proliferative activity. Lymph node metastasis was more chemosensitive than primary lesion, while liver metastasis was less. Gastric cancer expressing multidrug-resistance associated protein (MRP) showed lower sensitivity to several anticancer drugs, including adriamycin and etoposide. p53 status and susceptibility to apoptosis were also associated with chemosensitivity. Thus, chemosensitivity of clinical gastric cancer might be increased if these characters can be modified by some new biologic therapy.

[Response-oriented salvage chemotherapy with mitoxantrone, etoposide and enocitabine for previously treated acute myeloid leukemia. Tohoku Leukemia Study Group]

Twenty-two patients with previously treated acute myeloid leukemia (AML) received salvage chemotherapy with mitoxantrone, 5 mg/m2/d on days 1 to 3, etoposide, 70 mg/m2/d on days 1 to 5, and enocitabine, 170 mg/m2/d on days 1 to 7 (BHAC-ME). Additional mitoxantrone, etoposide (both for up to 2 days) and enocitabine (for up to 7 days) were given if the bone marrow obtained on day 8 was not severely hypoplastic. Mitoxantrone and etoposide had been previously administered in 14 and 15 patients, respectively. Seven patients had primary resistance; 14 patients had first relapse (4 early and 10 late): and 2 patients had second relapse. Overall, seven patients (31%) achieved a complete remission; 7/14 with first relapse, and 0/8 with primary resistance or second relapse. Four patients, 3 with primary resistance and 1 with first relapse, died of infectious complication in aplasia. First relapse patients who had been previously treated both with mitoxantrone and etoposide, had a lower CR rate than the other first relapse patients [2/8 (25%) vs 5/6 (86%)], although patient characteristics such as duration of first CR, initial karyotype, and performance status, were similar between the two groups. We conclude that response-oriented BHAC-ME regimen is still active in first relapse AML patients unless they have received both mitoxantrone and etoposide previously.

Chemical modification of metallic implant surfaces with biofunctional proteins (Part 1). Molecular structure and biological activity of a modified NiTi alloy surface

Human plasma fibronectin (pFN), an adhesive protein, was covalently immobilized onto an alkylaminosilane derivative of a NiTi substrate with glutaraldehyde through Schiff's base formation. The surface at different stages of the modification was characterized by X-ray photoelectron spectroscopy (XPS), and the amount of immobilized pFN was determined by a fluorometric method. The spreading behavior of human gingival fibroblasts was examined on the modified surface. The XPS spectra suggested that gamma-aminopropyltriethoxysilane (gamma-APS) was bonded to the surface through metallosiloxane bonds (Ti-O-Si) formed via a condensation reaction between the silanol end of gamma-APS and the surface hydroxyl group, with a highly cross-linked siloxane network formed after heat treatment of the silanized surface at 100 degrees C. The pFN was immobilized at the surface density of 1.1 micrograms.cm-2, and significantly promoted fibroblast spreading, suggesting that this chemical modification offers an effective means of controlling metal/cell interactions. These results may contribute to the development of bioactive metallic implants.

Chemical modification of metallic implant surfaces with biofunctional proteins (Part 2). Corrosion resistance of a chemically modified NiTi alloy

The corrosion resistance of a NiTi alloy, chemically modified with a human plasma fibronectin (pFN) using an aminosilane and a glutaraldehyde, was examined by electrochemical techniques in a 0.9% NaCl solution and a cell culture medium containing serum. The role of serum proteins in influencing the passive behavior of the alloy was extensively studied by anodic polarization and X-ray photoelectron spectroscopy (XPS). The passive current density increased in the presence of serum proteins. The enhanced dissolution of the passive film appears to be a consequence of quick adsorption of the serum proteins and the subsequent formation of metal ion-protein complexes on the film surface. With the chemical modification, the corrosion rate was reduced by approximately 50% in both solutions due to a highly cross-linked siloxane network formed on the alloy surface. This network layer limited the diffusion of dissolved oxygen, metal ions, and biological molecules involved in the corrosion reactions.

Magnetic resonance imaging study of the brain in aged volunteers: T2 high intensity lesions and higher order cortical function

The aims of the present study were to clarify the findings of magnetic resonance imaging (MRI) in the aging brain, and to relate the MRI findings to higher order cortical function. A total of 118 healthy aged volunteers (41 men, 77 women) underwent cranial MRI electroencephalography (EEG), Benton visual retention test (BVRT) and interview. The subjects had no past history or clinical evidence of cerebrovascular disorder, head trauma or dementia and were living at home without any difficulty. The majority of the subjects have participated in this series of studies since 1982. Using a 1.5 T superconductive MR instrument, T1-weighted, proton density and T2-weighted images were obtained. The MRI data were rated visually by regarding 12 items according to fixed criteria. T2 high signal intensity (T2HSI) lesions were found in 69.5% of subjects, the prevalence of which increased with age. T2HSI lesions were most frequently found in the basal ganglia (61.9%), followed by the thalamus (39.0%), parietal lobe (37.0%), temporal lobe (12.7%) and pons (8.5%). Among these lesions, lacunar infarction showed low signal intensity in T1-weighted images and was found in 24.6% of subjects, the prevalence also increasing with age. These findings, including brain atrophy determined according to similar criteria, were correlated closely with the subjects' age. The results of BVRT showed a close relation with T2HSI, suggesting that T2HSI may influence cognitive function. When the subjects were classified according to the presence of T2HSI, lacunar infarction and EEG abnormalities, brain atrophy was significantly milder in a group of subjects with T2HSI(-), lacunar infarction(-) and normal EEG than in the other groups. This suggests that changes seemingly representing physiological aging may be promoted by another pathological which also exerts influences on higher order cerebral function.

Inflammatory involvement of the hypophysis in Tolosa-Hunt syndrome

We report a case of painful ophthalmoplegia (Tolosa-Hunt syndrome), which was complicated with diabetes insipidus (DI) and pituitary-adrenal axis hypofunction. A 42-year-old man hospitalized for left orbital pain and impairment of left cranial nerves III, IV, V, VI, developed diabetes insipidus during the corticosteroid treatment. Neuroimaging studies disclosed a thickened, highly contrast-enhanced pituitary stalk, swollen pituitary gland and widened left cavernous sinus up to the superior orbital fissure, which were accompanied by diabetes insipidus and hypofunction of the pituitary-adrenal axis. These were indicative of an extension of granulomatous inflammation of the cavernous sinus to the pituitary portal system and the gland itself.

[Phase 3 multicenter clinical study of 111In-DTPA-D-octreotide (MP-1727) in patients with gastrointestinal hormone producing tumors]

A phase 3 multicenter clinical study was performed to investigate the efficacy, safety and usefulness of MP-1727, a novel tumor imaging agent which binds to somatostatin receptors, in 23 patients with gastrointestinal hormone producing tumor. The efficacy was graded effective or very effective in 16 cases (76.2%) out of 21 cases who could be evaluated. Positive predictive accuracy was 77.8% (7/9) for carcinoids, 100% (5/5) for gastrinomas and 40.0% (2/5) for insulinomas. In three cases, tumor lesions which had been unknown were detected by MP-1727 scintigraphy. The consistent ratio between scintigraphically positive sites and preinjection localizations was 82.0% (41/50 sites) in total. Although adverse drug reactions were observed in two cases, the safety was graded 'not problematic at all' in all of 23 cases. These results show that MP-1727 is a very useful radiopharmaceutical for detection and localization of gastrointestinal hormone producing tumors.

Alterations of effector cell molecule expression on neutrophils in granulocyte colony-stimulating factor-producing tumour

A 68-year-old man was diagnosed as having a granulocyte colony-stimulating factor (G-CSF)-producing mediastinal tumour. Mediastinotomy was performed, and thereafter the elevated leucocyte count and serum G-CSF concentration returned to the normal range. The surface expression of effector cell molecules on neutrophils was serially examined. Before operation, the expression of FcRI and CR1 was increased but the expression of FcRIII and L-selectin was reduced in the patient. The altered expression of these molecules returned to the normal levels after operation. These findings suggest that G-CSF produced by the tumour modulated neutrophil effector cell molecule expression in the patient.

Binding of vitamin D to low-density-lipoprotein (LDL) and LDL receptor-mediated pathway into cells

The present study was undertaken to identify serum components other than vitamin D-binding proteins that bind to 1,25(OH)2 D3, and its analog. The binding rate of 1,25(OH)2 D3, 22-oxa-1,25(OH)2D3 (OCT) or 25(OH) D3 to total lipoprotein(TLP) represented 16.7%, 4.65%, and 3.11% of total counts added, respectively. Polyacrylamide gel electrophoresis of the TLP revealed that 1,25(OH)2 D3 and OCT were associated with LDL. The binding studies of OCT-bound LDL to the fibroblasts showed specific pathway to the cells mediated by LDL-receptor. These findings may have important implications in understanding the mechanisms of the diverse biological actions of 1,25(OH)2 D3 and in designing a novel delivery system for vitamin D analogs.

Origin of posterior pituitary high intensity on T1-weighted magnetic resonance imaging. Immunohistochemical, electron microscopic, and magnetic resonance studies of posterior pituitary lobe of dehydrated rabbits

RATIONALE AND OBJECTIVES

To investigate the origin of posterior pituitary high intensity (PPHI) seen on T1-weighted magnetic resonance (MR) images.

METHODS

Six rabbits, including four rabbits deprived of drinking water for 4 days and two control rabbits, were examined by MR imaging. Plasma vasopressin levels were sequentially measured by radioimmunoassay. Pituitary glands were immunostained with guinea pig anti-rabbit vasopressin antibody, and ultrathin sections of Epon/Araldite-embedded specimens were observed with a transmission electron microscope.

RESULTS

In control rabbits, PPHI was noted on T1-weighted MR images, and the posterior pituitary lobe was positively immunostained with anti-vasopressin antibody. At the ultrastructural level, nerve terminals contained numerous neurosecretory granules bearing vasopressin. Conversely, plasma vasopressin levels gradually increased and PPHI was absent in 4-day dehydrated rabbits. The posterior lobe was scarcely stained with anti-vasopressin antibody, and neurosecretory granules were rarely observed. However, a number of small dispersed vesicles, possibly derived from the fragmentation of neurosecretory granule envelopes, were seen in the nerve terminal.

CONCLUSIONS

Posterior pituitary high signal seen on T1-weighted MR images is attributed to neurosecretory granules bearing vasopressin.

Synthesis and preliminary evaluation of [11C]KF15372, a selective adenosine A1 antagonist

As a radioligand for mapping the presynaptic adenosine A1 receptors in the central nervous system by PET, [1-propyl-11C]8-dicyclopropylmethyl-1,3-dipropylxanthine ([11C]KF15372), a selective adenosine A1 antagonist, was prepared by the reaction of 8-dicyclopropylmethyl-3-propylxanthine and [11C]propyl iodide with decay-corrected radiochemical yield of 5% based on the [11C]propyl iodide, radiochemical purity of > 99%, sp. at. of 10-56 GBq/mumol and preparation time of 45-55 min. Another 11C-labeled A1 antagonist with much lower affinity for the A1 receptors, 7-[11C]methyl-KF15372 ([11C]KF17109), was also prepared using [11C]methyl iodide with a decay-corrected radiochemical yield of > 50%. In mice, the brain uptake of [11C]KF15372 (1.91% ID/g at 5 min) decreased gradually with time. Carrier KF15372 competitively reduced the brain uptake to a level (43% of the control) comparable to the brain uptake of [11C]KF17109. On the other hand, an A2 antagonist 3,7-dimethyl-1-propargylxanthine showed no effect on the brain uptake of [11C]KF15372. The results show that [11C]KF15372 has potential as a PET radioligand for mapping the adenosine A1 receptors and that [11C]KF17109 may be a reference compound reflecting the non-specific uptake of the [11C]KF15372.

[Medical image transmission via communication satellite: evaluation of bone scintigraphy]

As compared with terrestrial circuits, the communication satellite possesses superior characteristics such as wide area coverage, broadcasting, high capacity, and robustness to disasters. Utilizing the narrow band channel (64 kbps) of the geostationary satellite JCSAT1 located at the altitude of 36,000 km above the equator, the authors investigated satellite-relayed medical images by video signals, with bone scintigraphy as a model. Each bone scintigraphy was taken by a handy-video camera, digitalized and transmitted from faculty of technology located at 25 kilometers apart from our department. Clear bone scintigraphy was obtained via satellite, as seen on the view box. Eight nuclear physicians evaluated 20 cases of bone scintigraphy. ROC (Receiver Operating Characteristic) analysis was performed between the scintigraphies on view box and via satellite by the rating method. The area under the ROC curve was 91.6 +/- 2.6% via satellite, and 93.2 +/- 2.4% on the view box and there was no significant difference between them. These results suggest that the satellite communication is very useful and effective system to send nuclear imagings to distant institutes.

[Current status of nuclear oncology in Japan]

The most commonly used radionuclides for cancer patients in Japan have been still 67Ga and 201T1 chloride. In addition to the diagnosis of lung cancer and thyroid tumor, 201T1 is recently applied to patients with brain tumor, bone and soft tissue tumor and parathynoid adenoma. Comparing to Nuclear Cardiology and Brain Nuclear Medicine, where many new radiopharmaceuticals have been developed, there are few new drugs in Nuclear Oncology. In other words, new radiopharmaceuticals are expected to be developed for the diagnosis and/or therapy of cancer. In addition to 131I for thyroid cancer, new radiopharmaceuticals such as 111In-octreotide and 99mTc(V)-DMSA have been clinically employed. In spite of strong expectation, radiolabeled monoclonal antibodies have not been clinically used in Japan. However, the technique of humanized antibodies has been established and in U.S.A., 131I-labeled antibodies are reported to be effective for the treatment of malignant lymphoma. 89Sr is useful for the relief of bone pain caused by the bone metastasis. New findings that SPECT of 18F-FDG, a positron emitter, has been revealed to have a great potential in the management of cancer patients, will give a great impact on Nuclear Oncology.

Repeating the avidin "chase" markedly improved the biodistribution of radiolabelled biotinylated antibodies and promoted the excretion of additional background radioactivity

Immunoscintigraphy using radiolabelled biotinylated monoclonal antibodies followed by infusion of avidin as a "chase" has been recently reported to improve the biodistribution for both immunoscintigraphy and radioimmunotherapy. In this study the circulating protein-bound and avidin-binding fractions of radiolabelled biotinylated antibodies were determined serially after injection of an avidin "chase", and the effect of repeating the avidin chase was also studied. Nude mice bearing KT005 human osteogenic sarcoma were injected with radiolabelled biotinylated antitumour monoclonal antibody (OST7). After injection of an avidin chase, the protein-bound and avidin-binding fractions in plasma were determined serially using the trichloroacetate method and avidin-Sepharose gel. The biodistribution of radiolabelled biotinylated OST7 was compared after single and double avidin chases with no chase. At 6 h after the first avidin chase in mice injected with radioiodinated and technetium-labelled biotinylated OST7, 67.7% and 67.8%, respectively, of the plasma radioactivity was available for binding to avidin and was cleared from the circulation. Reinjection of avidin decreased the plasma radioactivity and improved the biodistribution of the radiolabelled biotinylated antibodies. Repeating the avidin chase markedly improved the biodistribution of the radioiodine-labelled biotinylated antibody when compared with the use of a single avidin chase. This new method for radioimmunotherapy is sure to protect the critical organs from radiation injury without decreasing the therapeutic effect.

[Unilateral effective renal plasma flow measurement using one-compartment analysis of 99mTc-MAG3 and gamma-camera renography]

The aim of this study was to establish a simple and accurate procedure to calculate the unilateral effective renal plasma flow (ERPF) using 99mTc-MAG3 gamma-camera renographyl. Eleven patients with urological disorders were studied with 99mTc-MAG3 to calculate the renal uptake ratio (RUR), which was defined as the ratio of absorption-corrected renal counts within 1-2 min after intravenous injection to injection radioactivity measured with a gamma-camera. We assumed that 99mTc-MAG3 was distributed in the circulation, moved from the circulation to the kidneys, and was excreted solely from the kidneys. We thus adopted an one-compartment model to calculate 99mTc-MAG3 clearance (CLMAG) using RUR. Sequential p-aminohippurate (PAH) clearance study was performed as a gold standard in all the patients to compare CLMAG and PAH clearance. Obtained CLMAG correlated well with PAH clearance, and this one-compartment model seemed appropriate for describing CLMAG. Unilateral ERPF was accurately measured within two minutes after the intravenous injection of 99mTc-MAG3 in conjunction with the renal imaging study. This procedure is simple and reliable, and requires no blood or urine sampling.

Restoration of gap junctions in the regenerative process of ethanol-induced gastric mucosal injury

Gap junctions mediate intercellular communication and play an important role in cell proliferation and differentiation. The present study examined the expression of the gap junction protein connexin 32 in rat gastric mucosa during the regenerative process of ethanol-induced gastric mucosal injury. Absolute ethanol (0.5 mL/100 g bodyweight) was administered to rats via gastric intubation. Following the treatment, rats were killed periodically, and gastric tissues were processed for indirect immunofluorescence microscopy using an anti-connexin 32 antibody. Haematoxylin and eosin (H&E), periodic acid Schiff (PAS) and Bromodeoxyuridine (BrdU) staining were also performed in serial sections. Gastric injuries were limited in the mucosal layer. The injury was most severe 1 h after treatment, and was completely resolved by the 4th day after treatment. The number of immunoreactive spots for gap junctions was markedly decreased 1 h after the ethanol treatment. Reappearance of these immunostaining gap junctions occurred with repair of the injury. The reappearance of connexin 32 after injury was delayed in comparison with both the histologic resolution of the injury and the normalization of PAS-stained mucus. In contrast, the time course of reappearance of gap junctions closely paralleled the appearance of BrdU-labelled cells. These results indicate that morphologic repair is different to the recovery of cell maturity and cell proliferation in the regenerative gastric mucosa.

Vestibular inputs to the lateral tegmental field of the cat: potential role in autonomic control

The lateral tegmental field (LTF), which is comprised of the lateral reticular formation near the obex, is an important integrative area involved in cardiovascular control and the production of emesis. Using neuroanatomical and electrophysiological techniques, we tested the hypothesis that LTF neurons receive vestibular inputs; the neurons studied included those projecting into the subretrofacial rostral ventrolateral medulla (sRVLM), which contains cells that make direct connections with sympathetic preganglionic neurons. Injections of the anterograde tracer PHA-L into the medial and inferior vestibular nuclei produced labeled terminals in the LTF. Electrical stimulation of the vestibular nerve affected the firing rate of LTF neurons, including approximately one-third of those antidromically activated from the sRVLM. The response latencies ranged from 1.5 to 20 ms, suggesting that the neurons received both direct and polysynaptic vestibular inputs from the vestibular nuclei. The LTF may be involved in the production of vestibulosympathetic reflexes and vestibular-elicited vomiting.

GTP cyclohydrolase I gene in hereditary progressive dystonia with marked diurnal fluctuation

We previously reported four different mutations in the coding region of GTP cyclohydrolase I (GCH-I) gene in patients with hereditary progressive dystonia with marked diurnal fluctuation (HPD). We found two independent new mutations (leucine 79 proline and a deletion in exon 4) in patients with HPD. We also found four families of HPD without any mutations in the coding region of GCH-I gene.

Differential vasodilatory action of 2-octynyladenosine (YT-146), an adenosine A2 receptor agonist, in the isolated rat femoral artery and vein

The vasodilatory action of 2-octynyladenosine (YT-146), an adenosine A2 receptor agonist, was investigated in the isolated rat femoral artery and vein. Exposure to YT-146 resulted in preferential vasodilatation; the vein was completely dilated at YT-146 concentrations as low as 10(-7) M; in contrast, a concentration of YT-146 greater than 10(-4) M was necessary to induce complete relaxation in the femoral artery. 2-[p-(2-Carboxyethyl)-phenethylamine]-5'-N-ethylcarboxamidoadenosine (CGS 21680) also evoked stronger dilation in the vein than in the artery. The vasodilatory action of N6-cyclopentyladenosine (CPA) was much weaker in the vein than that of YT-146. YT-146-induced vasodilation in the artery was antagonized by neither 10(-7) M 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) nor 3 x 10(-6) M (E)-8-(3,4-dimethoxystylyl)-1,3-dipropyl-7-methylxanthine (KF17837), while the vasodilation in the vein was only antagonized by KF17837, suggesting that the vasodilation may involve adenosine A2 receptor activation in the vein. However, the present study did not provide evidence of a link between adenosine agonist-induced vasodilation and adenosine A2 receptor activation in the artery. The addition of 10(-4) M N omega-nitro-L-arginine partially reversed YT-146-induced vasodilation in the artery, but not in the vein. The reversal of YT-146-induced vasodilation by N omega-nitro-L-arginine in the artery was attenuated by the addition of 10(-3) M L-arginine. Removal of the endothelium decreased YT-146-induced vasodilation in the artery, but not in the vein.(ABSTRACT TRUNCATED AT 250 WORDS)

[Measurement of serum TSH receptor antibodies in thyroid patients using TRAb Dade kits]

TRAb Dade kit is a radioreceptor assay that detects autoantibodies in serum of patients with thyroid diseases which interfere with the binding of 125I labeled TSH to its receptor. In this paper we examined the basic and clinical usefulness of newly developed TRAb assay kits. The intra and inter assay coefficients of variation were 7.9% and 8.4%, respectively. There was no significant effect of temperature and incubation time on TRAb values. The influence of conjugated, unconjugated bilirubin, hemoglobin and turbidity was not so significant on TRAb values. TRAb values in serum of 68 untreated Graves' disease were above the normal range, but most (78%) treated Graves' patients who became euthyroid after receiving antithyroid drug, showed the normal range. In patients with chronic renal failure TRAb values were also within the normal range. A significant correlation (y = 1.0x-0.88, r = 0.95) was observed between this TRAb kit and TRAb Cosmic values in various thyroid conditions. This new assay for TRAb was simple, rapid and reproducible. The measurement of serum TRAb values was useful for the evaluation of physiological and pathological function and seemed to be helpful in the management of patients with thyroid disease.

Experimental study of nerve regeneration in a biodegradable tube made from collagen and polyglycolic acid

The authors developed a novel bioabsorbable nerve conduit to induce nerve regeneration across long gaps. It is a composite tube made of polyglycolic acid mesh coated with collagen. Seven cats underwent 25 mm resection of the left sciatic nerve. The proximal and distal nerve stumps were inserted into the tube and fixed with sutures to bridge the 25 mm gap between them. Histologic examination 4 months after implantation of the tube showed regeneration of nerve tissue structure, including myelinated axons and Schwann cells, and somatosensory evoked potentials and electromyograms demonstrated functional recovery of the regenerated nerves. Horseradish peroxidase staining revealed restoration of anterograde and retrograde axonal transport. These results indicate that this polyglycolic acid-collagen composite tube is promising as a nerve conduit that provides adequate nerve regeneration.

Vertical vestibular input to and projections from the caudal parts of the vestibular nuclei of the decerebrate cat

1. To investigate the type of vestibular signals that neurons in the caudal parts of the vestibular nuclei transmit to the cerebellum and spinal cord, we studied their responses to natural vestibular stimulation in vertical planes in decerebrate cats with the caudal cerebellum removed. Most neurons were in the caudal half of the descending vestibular nucleus, the remainder at corresponding levels of the medial nucleus or the medial-descending border. 2. Dynamics of the responses of spontaneously firing neurons were studied with sinusoidal tilts delivered at 0.05-1 Hz near the plane of body rotation that produced maximal modulation of the neuron's activity (response vector orientation). For most neurons the predominant vestibular input could be identified as coming from otolith organs (46%) or vertical semicircular canals (37%). Some neurons had otolith+canal convergence (9%) and others either had such converging input or some other form of central processing (8%). 3. Gain and phase of the responses of otolith neurons were comparable with values obtained in earlier studies on Deiters' nucleus and the rostral descending nucleus. Many canal neurons had a steeper gain slope and more advanced phase than observed previously for more rostral neurons. This may be due to more irregular afferent input to many neurons or to the absence of the vestibulocerebellum. 4. Response vector orientations of canal neurons were closely bunched near the planes of the ipsilateral vertical canals. The small number of contralaterally projecting vectors showed evidence of convergence between the two contralateral vertical canals. As is the case elsewhere in the vestibular nuclei, there was no evidence of convergence from bilateral vertical canals. Response vector orientations of otolith neurons were restricted to the roll quadrants; the majority pointed ipsilaterally. 5. Antidromic stimulation with an electrode in the restiform body or with several electrodes in the dorsal half of the white matter of the upper cervical cord was used to identify neurons projecting to the cerebellum and spinal cord, respectively. A substantial number of spontaneously firing neurons projected to the cerebellum, but there were few spontaneously active vestibulospinal neurons. The properties of the vestibular input to cerebellar-projecting neurons were the same as those of the population as a whole, but the effect of tilt on vestibulospinal neurons appeared weak or absent. 6. Many neurons were inhibited by stimulation of the restiform body. We suggest that this is mainly due to stimulation of the axons of vestibulocerebellar Purkinje cells. 7. Our results demonstrate a robust vertical vestibular input to the caudal parts of the vestibular nuclei.(ABSTRACT TRUNCATED AT 400 WORDS)

Evidence for inter-generational instability in the CAG repeat in the MJD1 gene and for conserved haplotypes at flanking markers amongst Japanese and Caucasian subjects with Machado-Joseph disease

The size of the (CAG)n repeat array in the 3' end of the MJD1 gene and the haplotype at a series of microsatellite markers surrounding the MJD1 gene were examined in a large cohort of Japanese and Caucasian subjects affected with Machado-Joseph disease (MJD). Our data provide five novel observations. First, MJD is associated with expansion fo the array from the normal range of 14-37 repeats to 68-84 repeats in most Japanese and Caucasian subjects, but no subjects were observed with expansions intermediate in size between those of the normal and MJD affected groups. Second, the expanded allele associated with MJD displays inter-generational instability, particularly in male meioses, and this instability was associated with the clinical phenomenon of anticipation. Third, the size of the expanded allele is not only inversely correlated with the age-of-onset of MJD (r = -0.738, p < 0.001), but is also correlated with the frequency of other clinical features [e.g. pseudoexophthalmos and pyramidal signs were more frequent in subjects with large repeats (p < 0.001 and p < 0.05 respectively)]. Fourth, the disease phenotype is significantly more severe and had an early age of onset (16 years) in a subject homozygous for the expanded allele, which contrasts with Huntington disease and suggests that the expanded allele in the MJD1 gene could exert its effect either by a dominant negative effect (putatively excluded in HD) or by a gain of function effect as proposed for HD. Finally, Japanese and Caucasian subjects affected with MJD share haplotypes at several markers surrounding the MJD1 gene, which are uncommon in the normal Japanese and Caucasian population, and which suggests the existence either of common founders in these populations or of chromosomes susceptible to pathologic expansion of the CAG repeat in the MJD1 gene.

Remarkable activity enhancement of thermolysin mutants

Most attempts to modify the properties of enzymes by amino acid substitution around the active sites have resulted in suppression of the biological activity, suggesting that the structure of natural enzymes should be almost optimized evolutionally to show the highest activity. In contrast, we found an interesting site of a well-known metalloendopeptidase, thermolysin (EC.3.4.24.4), where almost all the amino acid replacement causes a remarkable increase in the hydrolytic activity. Negative correlation between the activity and the thermal stability was observed. The flexibility around the substrate binding site is suggested to be a key to the correlation. Nature may have selected the amino acid at this site, which suppresses the flexibility of the molecule, to get the highest thermal stability at the expense of the activity.

POEMS syndrome with central nervous system involvement: a case report

POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes) syndrome was found to be associated with a disorder of the central nervous system (CNS) in a 56-year-old woman. Elevated intracranial pressure, neuroimaging evidence of diffuse white matter edema and papilledema point to a disease process affecting the CNS. Brainstem auditory (BAEPs) and visual evoked potentials (VEPs) also provided evidence of reduced central conduction velocities without, however, apparent clinical deficits attributable to CNS involvement. The intracranial hypertension is thought to be a part of a generalized tendency toward edema characteristic of this particular syndrome. We speculate that POEMS syndrome is an autoantibody-mediated immunological disorder in which cerebral vascular endothelium is one of the targets of the immunopathogenetic process and undergoes subsequent enhancement of vascular permeability.