Double-hadron leptoproduction in the nuclear medium

The first measurements of double-hadron production in deep-inelastic scattering within the nuclear medium were made with the HERMES spectrometer at DESY HERA using a 27.6 GeV positron beam. By comparing data for deuterium, nitrogen, krypton, and xenon nuclei, the influence of the nuclear medium on the ratio of double-hadron to single-hadron yields was investigated. Nuclear effects on the additional hadron are clearly observed, but with little or no difference among nitrogen, krypton, or xenon, and with smaller magnitude than effects seen on previously measured single-hadron multiplicities. The data are compared with models based on partonic energy loss or prehadronic scattering and with a model based on a purely absorptive treatment of the final-state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter.

Measurement of the tensor structure function b1 of the deuteron

The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry A(d)zz and the tensor structure function b(d)1 for average values of the Bjorken variable 0.01< <x> <0.45 and of the negative of the squared four-momentum transfer 0.5 GeV2 < <Q2> <5 GeV2. The quantities A(d)zz and b(d)1 are found to be nonzero. The rise of b(d)1 for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering.

Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target

Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion (phi) and the target spin axis (phi(S)) about the virtual-photon direction and relative to the lepton scattering plane. The extracted Fourier component sin((phi+phi(S))(pi)(UT) is a signal of the previously unmeasured quark transversity distribution, in conjunction with the Collins fragmentation function, also unknown. The component sin((phi-phi(S)(pi)(UT) arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson production.

Flavor decomposition of the sea-quark helicity distributions in the nucleon from semiinclusive deep inelastic scattering

Double-spin asymmetries of semiinclusive cross sections for the production of identified pions and kaons have been measured in deep inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with reanalyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.

Q2 dependence of nuclear transparency for exclusive rho0 production

Exclusive coherent and incoherent electroproduction of the rho(0) meson from 1H and 14N targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q2). The ratio of 14N to 1H cross sections per nucleon, called nuclear transparency, was found to increase (decrease) with increasing l(c) for coherent (incoherent) rho(0) electroproduction. For fixed l(c), a rise of nuclear transparency with Q2 is observed for both coherent and incoherent rho(0) production, which is in agreement with theoretical calculations of color transparency.

The carbohydrate moiety of the bermuda grass antigen BG60. New oligosaccharides of plant origin

BG60 is an important allergen of Bermuda grass (Cynodon dactylon) pollen, which causes allergic responses in human. It was suggested that its carbohydrate moiety may be relevant to allergic reaction (Su, S. N., Lau, G. X., Shu, P., Yang, S. Y., Huang, S. W., and Lee, Y. C. (1996) J. Allergy Clin. Immunol., in press). Therefore, the structure of the carbohydrate moiety in BG60 was investigated. The N-linked oligosaccharides were released from the glycopeptides of BG60 by digesting with a glycoamidase from sweet almond and reductively aminated with a fluorescent reagent, 2-aminopyridine. The mixture of pyridylaminated oligosaccharides were separated by high-performance liquid chromatography (HPLC) using an octadecylsilyl (ODS) column. Five oligosaccharide fractions were isolated, and each fraction was found to be homogeneous by HPLC on an amide-silica column. The structure of each of the oligosaccharides was analyzed by the two-dimensional mapping technique (Tomiya, N., Awaya, J., Kurono, M., Endo, S., Arata, Y., and Takahashi, N. (1988) Anal. Biochem. 171, 73-90), in tandem with sequential exoglycosidase digestion. The two most abundant oligosaccharides, A and B, have an unusual structural feature, i.e. the presence of an L-Fuc alpha-(1,3)-linked to Asn-linked GlcNAc without a Xyl beta-(1,2)-linked to the branching Man (see below). To the best of our knowledge, these are the first such oligosaccharides found in plant glycoproteins.

Morphological changes of cultured neuronal and endothelial cells by human albumin

The role of plasma proteins in the mechanisms of brain tissue damage in ischemic events remains to be clarified. The purpose of this study was to investigate whether the presence of albumin in the extracellular fluid could induce damage to endothelial and neuronal cells. Neuronal cells from rat fetal brain (15 days) were cultured by using RPMI-1640 containing 10% Serum-Plus and endothelial cells from umbilical vein were also cultured in 96-well plates. The studies were made by using neuronal cells after 4 days of culture (N group) and endothelial cells after 4 days of culture (E4 group) and at confluence (EC group). After discarding the culture fluid, 200 microliters of 5-25% human albumin was added to each well. Microscopic observations were made up to 20 minutes, and then immunostaining was done with anti-human albumin antibody. The swelling of neurons was observed immediately after application of albumin solution, and the cells became circular after 10 minutes. In the E4 group, similar morphological changes were observed, but no such changes were seen in the EC group. Immunostaining revealed the presence of albumin in the intracellular space in both the N and E4 groups, but not the EC group. Our results suggest that albumin in extravasated fluid can induce damage to neuronal cells and endothelial cells in the non-confluent state.

Genomic structure of the gene for copper/zinc-superoxide dismutase in rice

We have isolated and determined the nucleotide sequence of the structural gene (sodB) coding for one of the copper/zinc-superoxide dismutase (Cu/Zn-SOD) isozymes from rice plants (Oryza sativa L.). The sodB gene is split into 8 exons spread about 2 kb of the chromosomal DNA, with the coding sequence beginning in the 2nd and ending in the 8th. Although none of sodB introns are inserted into similar positions in Cu/Zn-SOD genes from other sources, four of six introns in the protein-coding region are located at discriminating positions within structural domains of the protein. Genomic Southern analysis indicated that cytosolic Cu/Zn-SOD is coded for by 2-3 genes in the rice genome.

[Asymptomatic cerebral hemorrhage detected by MRI]

Detection of previous cerebral infarction on CT films of patients with no history of stroke is a common occurrence. The incidence of silent cerebral infarction was reported to be about 10 to 11 percent, but very few reports concerning asymptomatic cerebral hemorrhage available. However, recent clinical application of MRI has resulted in the detection of old asymptomatic hemorrhage in patients with no history of known stroke-like episodes. The purpose of this study was to elucidate the incidence, the cause and the character of the asymptomatic cerebral hemorrhage among patients who had undergone MRI examinations. From September 1987 till June 1990, 2757 patients have undergone 3474 times of MR scan of the brain with 1.0 Tesla Siemens Magneton unit in our hospital. 17 patients showed no clinical signs or symptoms suggesting a stroke episode corresponding to the detected hemorrhagic lesion. Seventeen patients correspond to 0.6% of the patients who underwent MRI, 1.5% of the patients with cerebrovascular disease and 9.5% of the patients with intracerebral hemorrhage, which was rather higher than expected. Among the 17 patients, 12 were diagnosed as primary ICH and 5 as secondary ICH. Most of the primary asymptomatic hemorrhages were hypertensive ones and slit-like curvilinear lesions between the putamen and claustrum or external capsule. The secondary asymptomatic hemorrhages were due to AVM and angiomas in the frontal cortex, thalamus and pons.

Routed protein migration after protein extravasation and water leakage caused by cold injury

The movement of extravasated endogenous protein induced by cold injury was investigated in the rat. Extravasated proteins were observed around the cold injury immediately after injury; within 3 hr they had moved into the ipsi- and contralateral hemispheres along the nerve fibres (routed protein migration). The water content in the areas where the extravasated protein was observed was increased, and NMR-CT scans (TR 2000 msec, TE 90 msec) showed high intensity patterns whose distribution and progression coincided with those of extravasated protein. NMR relaxation time, T1, showed a slight increase in the area where the extravasated protein was observed, but T2 value did not show any significant changes. In the opposite hemisphere, CBF decreased within 3 to 6 hours after injury. Local cerebral glucose utilization was reduced, but this change occurred more than 6 hours after injury. These results indicate that water leakage and protein extravasation occur simultaneously after the injury without any significant change of water state or protein conformation. Subsequently, a reduction of CBF is induced, which is followed by changes in cerebral metabolism.

[Case report: hemiballism due to a putaminal cavernous hemangioma]

A rare case of reversible hemiballism due to putaminal pathological process in a 51-year-old woman is described. She was hospitalized for evaluation of hemiballism and muscle weakness on the left side. A cranial computed tomography scan demonstrated a high density lesion in the right putamen with enhancement on delayed scan. Angiographic examination revealed no apparent abnormalities. Magnetic resonance imaging with T1 weighted showed a isodense lesion in the right putamen, while T2 weighted image revealed a ring like low signal area around a high signal lesion. These findings were compatible with the diagnosis of cavernous hemangioma. In order to establish the final diagnosis, CT-guided stereotaxic biopsy was carried out. But histological specimen showed only gliosis and calcification. Immediately after the biopsy, a small hemorrhage took place in the right putamen extending to the head of caudate nucleus head. Following this episode, hemiballism ceased, however, it gradually returned along with absorption of hemorrhage. The speculated pathophysiology of this on-and-off hemiballism was as follows; it initially developed as the result of suppression of inhibitory fibers from the striatum to the pallidum by a minor hemorrhage of putaminal cavernous hemangioma, and ceased by declining the activities of the pallidum due to interruption of excitatory fibers from the thalamus and the cortex to the striatum.

[Metabolic acidosis and hypoglycemia during calcium hopantenate administration--report on 5 patients]

Calcium hopantenate (HOPA) has been widely used as an activator of cerebral metabolism in Japan. However, several cases of acute encephalopathy during HOPA administration were recently reported, which were characterized by marked metabolic acidosis and hypoglycemia. The encephalopathy in these patients was named Reye-like syndrome because of the similarity to Reye's syndrome in children. The purposes of this presentation are to report on 5 patients with acute encephalopathy developing during HOPA administration, to summarize their symptoms and clinical courses, and to discuss the pathogenesis of metabolic acidosis and hypoglycemia. Initial characteristics of the clinical course in all patients were loss of appetite, nausea and vomiting, followed by unconsciousness. Laboratory examinations revealed marked metabolic acidosis, severe hypoglycemia, hyperlactacidemia, leukocytosis, ketonuria, and increased Ht and BUN. A few days after development of the initial symptoms, mild renal and liver dysfunction, and elevation of serum amylase were observed in all patients. Hyperlactacidemia was present in 4 in the initial period. Blood concentration of HOPA was 2.131 micrograms/ml in patient 1 (8-10 hours after final administration), and 10.7 micrograms/ml in patient 5 (24 hours after final administration). These values are extremely high, because usually HOPA concentration is almost negligible 7 hours after the drug is taken. As the pathogenesis of acute encephalopathy due to HOPA administration, the failure of fatty acid beta-oxidation has been proposed by some investigators. However, the serum concentrations of CoA, pantothenic acid and carnitine during the initial stage were not reduced in our patients. Furthermore, it is very difficult to explain the severe hypoglycemia in terms of the beta-oxidation theory.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical application of biofeedback treatment with a microvibration transducer

This article demonstrates one clinical application of biofeedback treatment with a microvibration (MV) transducer to relieve functional tremors. A MV transducer, a kind of accelerometer, was originally developed to detect invisible tremors from the body surface but this equipment is also utilized to detect visible tremors to convert them to auditory signals. Our method uses almost the same procedure as electromyographic biofeedback treatment. The threshold level for production of auditory signals should be determined as high as possible between the superimposed amplitudes of essential MV and tremor components. As the sessions progress, the predeterminate threshold level should be gradually lowered to almost the same amplitude as MV itself. In determining the threshold, it is more appropriate to utilize records of the frequency band in which the tremor components are described more clearly, in order to remove noises or MV waves of different frequency ranges. Because of the high sensitivity of this accelerometer, such "tremor feedback" treatment can be recommended only if the tremor is present while the patient is resting or remains still.