Quasilinear quantum magnetoresistance in pressure-induced nonsymmorphic superconductor chromium arsenide.

In conventional metals, modification of electron trajectories under magnetic field gives rise to a magnetoresistance that varies quadratically at low field, followed by a saturation at high field for closed orbits on the Fermi surface. Deviations from the conventional behaviour, for example, the observation of a linear magnetoresistance, or a non-saturating magnetoresistance, have been attributed to exotic electron scattering mechanisms. Recently, linear magnetoresistance has been observed in many Dirac materials, in which the electron-electron correlation is relatively weak. The strongly correlated helimagnet CrAs undergoes a quantum phase transition to a nonmagnetic superconductor under pressure. Here we observe, near the magnetic instability, a large and non-saturating quasilinear magnetoresistance from the upper critical field to 14 T at low temperatures. We show that the quasilinear magnetoresistance may arise from an intricate interplay between a nontrivial band crossing protected by nonsymmorphic crystal symmetry and strong magnetic fluctuations.

Superconductivity and magnetic fluctuations developing in the vicinity of strong first-order magnetic transition in CrAs.

We report single crystal preparation, resistivity, and nuclear quadrupole resonance (NQR) measurements for new pressure-induced superconductor CrAs. In the first part, we present the difference between crystals made by different thermal sequences and methods, and show the sample dependence of superconductivity in CrAs. In the latter part, we show NQR data focusing the microscopic electronic state at the phase boundary between the helimagnetic and the paramagnetic phases. They suggest strongly that a quantum critical point is absent on the pressure-temperature phase diagram of CrAs, because of the strong first-order character of the magnetic transition; however, the spin fluctuations are observed in the paramagnetic phase. The close relationship between the spin fluctuations and superconductivity can be seen even in the vicinity of the first-order magnetic transition in CrAs.

Traumatic injury-induced BMP7 expression in the adult rat spinal cord.

It has been reported that bone morphogenetic proteins (BMPs) are involved in the generation of the central nervous system during development. However, the roles of BMPs in mature spinal cord have not been clarified. We examined the expression of BMP7 mRNA before and after traumatic injury of the adult rat spinal cord. BMP7 mRNA was already detectable at a relatively low level in uninjured spinal cord, but was dramatically increased after injury. Semiquantitative RT-PCR study further confirmed upregulation of BMP7 mRNA in injured spinal cord. In situ hybridization indicated that expression of BMP7 mRNA was present only in glial cells in uninjured spinal cord. After injury, the number of BMP7-expressing glial cells was increased, BMP7 expression also became apparent in motor neurons. It has been suggested that BMPs promote survival of subventricular zone cells in adult rats. Thus, our results suggest that increase in the expression of BMP7 promotes survival of neurons and glial cells after acute traumatic injury. In contrast, there is increasing evidence that BMPs inhibit neurogenesis and alternatively promote gliogenesis of neural progenitors, which are also present in adult spinal cord, suggesting that injury-upregulated BMP7 may regulate differentiation of glial cells from neural progenitors and may induce gliosis after central nervous system injury.

Apical leakage of obturated canals prepared by Er:YAG laser.

The present study evaluates the degree of apical leakage in vitro after root canal preparation using Er:YAG laser irradiation followed by obturation. Twenty-four single-rooted teeth were divided into 2 groups of 12. One group served as a control and these root canals were conventionally prepared up to a #50K file. The other group was prepared by Er:YAG laser irradiation at parameters of 2 Hz and 170 to 230 mJ/pulse. After obturation the teeth were immersed in a vacuum flask containing 0.6% rhodamine for 48 h, longitudinally bisected, and observed by stereoscopy and scanning electron microscopy. The degree of apical leakage from an apical stop was measured and statistical analysis was performed. The degree of apical leakage from the teeth prepared by laser was not significantly less than that from control teeth (p > 0.01). Morphological findings showed that contact between the root canal walls and obturated materials was hermetic in both groups, but canal walls prepared by laser were rough and irregular. These results show that root canal preparation by laser does not affect apical leakage after obturation compared with leakage in canals prepared using the conventional method.

Postmodern midwives in Japan: the offspring of modern hospital birth.

Although childbirth is fundamentally involved with the issue of women's bodies, it is also involved with such social values as politics, economics, medicine, and other phenomena characteristic of a particular time and culture. In this article I divide Japanese society and childbirth into pre-modern, modern, and postmodern phases, with special emphasis on the postmodern phase. I use the word "postmodern" to denote visible changes in childbirth and midwifery that began to occur around 1990 - changes that distinguish it from modern hospital birth. I conclude that postmodern midwifery is a reaction to and a consequence of modern hospital birth, which failed to satisfy a large number of women's needs. In this sense, postmodern midwifery could rightly be said to be the offspring of modern hospital birth.

Histopathological analysis of four autopsy cases of HTLV-I-associated myelopathy/tropical spastic paraparesis: inflammatory changes occur simultaneously in the entire central nervous system.

Although brain lesions have been described in some cases with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), little is known about the nature of brain lesion and its relation to the spinal cord lesion. In the present study, we performed histopathological analysis of the brain and the spinal cord of four autopsied cases with HAM/TSP to clarify the relationship between the brain and the spinal cord lesions. In two cases with active-chronic inflammation in the spinal cord, perivascular inflammatory infiltration was also seen in the brain, and the composition of cell subsets was similar both in the spinal cord and in the brain. No active inflammatory change was seen in the brain in two cases with inactive-chronic spinal cord lesions. Inflamed vessels were distributed mainly in the deep white matter and in the area between cerebral cortex and white matter of the brain. In the spinal cord inflamed vessels were mainly seen in the bilateral lateral and the ventral posterior columns. Parenchymal infiltration was diffused in the spinal cord but very sparse in the brain, suggesting the importance of parenchymal infiltration in the destruction of tissues. These results suggest that inflammatory changes occurred simultaneously in the spinal cord and in the brain, and that distribution of inflamed vessels closely correlated with the characteristics of vascular architecture of the brain and the spinal cord, which lead to a slow blood flow. This study may help promote a better understanding of the pathogenesis of HAM/TSP.

CD44 splice variant involvement in the chronic inflammatory disease of the spinal cord: HAM/TSP.

Splice variants of CD44 molecule-harboring exon 10 (v6), often called v6 variants (v6v), are shown to confer tumor progressive, metastatic or invasive capacities. Furthermore, CD44 molecule on activated T-cells are shown to be required for infiltration of these cells into the inflammatory site and for accelerated immune response. Human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is caused by HTLV-I infection and characterized by spastic paraparesis and urinary disturbance with perivascular HTLV-I-infected and activated CD4+ T-cell infiltration. In order to explore the underlying mechanism causing the disease after HTLV-I infection, we analyzed CD44 variant expression on peripheral blood mononuclear cells (PBMC) and in the spinal cord specimens from patients with HAM/TSP, and compared them with those from other HTLV-I-infected individuals and controls. We found that v6v expression with special direct link of exons 10 (v6) and 14(v10) was highly expressed in PBMC from patients with HAM/TSP and that v6v and CD4 double positive T-cell infiltration into the spinal cord lesion of HAM/TSP. This combination of CD44 splice variant has not been previously reported in the study of chronic inflammatory disorders and may be a marker molecule for T-cells infiltrating into the central nervous system (CNS), especially the spinal cord.

Morphological study on the capability of Er:YAG laser irradiation for root canal preparation.

OBJECTIVE: The purpose of this study was to evaluate morphologically the capability of Er:YAG laser irradiation for root canal preparation in vitro. BACKGROUND DATA: There have been no reports on root canal preparation using Er:YAG laser irradiation. METHODS: Forty extracted human teeth were divided randomly into two groups of 20. Laser irradiation was performed using three different sizes of fiber tips at the two different parameters (G 1, 2 Hz and 136-184 mJ/pulse; G 2, 2 Hz and 170-230 mJ/pulse). After laser irradiation, the teeth were bisected longitudinally and observed by stereoscopy and field emission-scanning electron microscopy (FE-SEM). The time required for preparation in each group was recorded and the achievement degree of root canal preparation was scored according to our criteria. Statistical analysis of the times was performed using one-way analysis of variance (ANOVA). A value of p < 0.01 was considered significant. RESULTS: Root canals were prepared using laser irradiation at 50% of teeth in G 1 and 40% in G 2. Remnant pulp tissue after laser irradiation was observed at 30% of teeth in G 1, but not recognized in G 2. Irradiated areas were scale-like and clean, but rough and irregular by FE-SEM. The statistical analysis revealed that the time required for preparation at high energies was significantly shorter compared with that at low energies (p < 0.01). CONCLUSION: These results suggest that Er:YAG laser irradiation is capable of root canal preparation if appropriate parameters are selected.

A rat model of human T lymphocyte virus type I (HTLV-I) infection: in situ detection of HTLV-I provirus DNA in microglia/macrophages in affected spinal cords of rats with HTLV-I-induced chronic progressive myeloneuropathy.

To investigate the pathogenetic role of human T lymphocyte virus type I (HTLV-I) in central nervous system disease, a rat model for HTLV-I-associated myelopathy/tropical spastic paraparesis, designated as HAM rat disease, has been established. Wistar-King-Aptekman-Hokudai strain rats with induced HTLV-I infection develop a chronic progressive myeloneuropathy with paraparesis of hind limbs after an incubation period of 15 months. In the affected spinal cord in these rats, white matter degeneration, demyelination and vacuolar change with microglia/macrophage infiltration are present as are the provirus DNA and the virus mRNA. To identify infected cells in the affected lesions, we carried out in situ hybridization of amplified fragments of the provirus DNA by polymerase chain reaction on thin sections, plus immunohistochemistry on the same sections. The provirus DNA was localized in some microglia/macrophages in the spinal cord lesion. In addition, the HTLV-I provirus was clearly evident not only in ED-1-negative lymphoid cells but also in ED-1-positive macrophages from lymph nodes. These observations suggest that cells of microglia/macrophage lineage may be one of dominant viral reservoirs in the spinal cords and lymph nodes in HAM rat disease. These infected microglia/macrophages may relate to cause the myeloneuropathy through neurotoxic cytokine synthesis.

Molecular pathologic analysis of the tonsil in HTLV-I-infected individuals.

Little is known about the role of the tonsils in HTLV-I infection. We performed molecular pathologic studies of tonsils in individuals positive or negative for anti-HTLV-I antibodies (HTLV-I-Ab) to clarify histologic characteristics of tonsils in HTLV-I infection. We collected tonsils and peripheral blood samples from patients who underwent tonsillectomy in a prospective manner. HTLV-I-Ab in serum was examined and presence of HTLV-I provirus was detected by polymerase chain reaction (PCR) in extracted DNA of both peripheral blood and tonsils. Histopathologic and immunohistochemical evaluations of tonsils were performed. HTLV-I seropositivity and PCR detection of HTLV-I provirus matched perfectly. Tonsil samples from seropositive individuals showed atrophy of the mantle zone and high numbers of T cells in the marginal zone compared with findings in HTLV-I-negative samples. HTLV-I provirus could be detected only from extracted DNA of extrafollicular areas. PCR in situ hybridization also showed positive signals in some mononuclear cells located in the marginal zone. There was a significant correlation between HTLV-I proviral load in tonsils and in peripheral blood. These results suggest the presence of characteristic histologic changes and deviated localization of HTLV-I-infected cells in the tonsils of individuals positive for HTLV-I.

Perivascular T cells are infected with HTLV-I in the spinal cord lesions with HTLV-I-associated myelopathy/tropical spastic paraparesis: double staining of immunohistochemistry and polymerase chain reaction in situ hybridization.

HTLV-I-infected cells play an important role in pathogenesis HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Our previous studies of quantitative polymerase chain reaction (PCR) and in situ PCR suggested that T cells infiltrating in the spinal cord lesion were infected with HTLV-I. To elucidate the localization of HTLV-I proviral DNA directly, we performed double staining using immunohistochemistry and PCR in situ hybridization (PCR-ISH). Fresh frozen sections of the spinal cord from four HAM patients taken at autopsy were first immunostained with antibodies to pan T cells (UCHL-1), macrophages (KP-1) and helper/inducer T cells (OPD4). Then PCR-ISH was carried out with specific primers and probe for the HTLV-I pX region. UCHL-1-positive cells were noted around perivascular areas and, to some extent, in the parenchyma. Of the UCHL-1-positive cells, 9.4% (case 1), 9.6% (case 2), 1.1% (case 3) and 6.7% (case 4) became positive in HTLV-I PCR-ISH. UCHL-1-negative cells were HTLV-I PCR-ISH negative and almost all KP-1-positive cells were HTLV-I negative. HTLV-I was localized to OPD4-positive cells in examined lesions of cases 2 and 4. These data are a direct demonstration of HTLV-I proviral DNA localizing to infiltrated T cells in HAM/TSP spinal cord lesions.

Studies on the removal of debris near the apical seats by Er:YAG laser and assessment with a fiberscope.

OBJECTIVES: The purposes of this study were to investigate the effect of Er:YAG laser to remove debris near the apical seats in root canals and to evaluate the efficacy of a fiberscope for the assessment of remnant debris on the root canal wall in vitro. SUMMARY BACKGROUND DATA: There has been no report to evaluate residual debris in root canals after Er:YAG laser irradiation using a fiberscope. METHODS: After cleansing and shaping by a one step back method with the alternative irrigation of hydrogen peroxide and sodium hypochlorite solution, 80 extracted single root human teeth with straight canals were randomly divided into four groups. The teeth of groups 1, 2, and 3 were irradiated by Er:YAG laser at the parameters of 1 W, 2 W, and 3 W, respectively. Group 4 was comprised of control specimens that were not lased. After laser irradiation, the remnant debris on the apical portions of all root canals was evaluated by fiberscopy. The teeth were then bisected longitudinally, and the specimens were observed by stereoscopy and scanning electron microscopy (SEM). The degree of remaining debris on the apical seats was scored. RESULTS: The degree of remaining debris observed by fiberscopy coincided with the results by SEM. There was no significant difference between groups 1 and 4, and also between groups 2 and 4, but the remaining debris in group 3 was significantly decreased after Er:YAG laser irradiation compared with that in group 4 (p < 0.01). CONCLUSIONS: These results suggest that Er:YAG laser irradiation is effective for removal of debris near the apical seats and that a fiberscope is useful for the evaluation of the remaining debris near the apical seats of intact teeth.

Identification and classification of 16 new kinesin superfamily (KIF) proteins in mouse genome.

KIF (kinesin superfamily) proteins are microtubule-dependent molecular motors that play important roles in intracellular transport and cell division. The extent to which KIFs are involved in various transporting phenomena, as well as their regulation mechanism, are unknown. The identification of 16 new KIFs in this report doubles the existing number of KIFs known in the mouse. Conserved nucleotide sequences in the motor domain were amplified by PCR using cDNAs of mouse nervous tissue, kidney, and small intestine as templates. The new KIFs were studied with respect to their expression patterns in different tissues, chromosomal location, and molecular evolution. Our results suggest that (i) there is no apparent tendency among related subclasses of KIFs of cosegregation in chromosomal mapping, and (ii) according to their tissue distribution patterns, KIFs can be divided into two classes-i.e., ubiquitous and specific tissue-dominant. Further characterization of KIFs may elucidate unknown fundamental phenomena underlying intracellular transport. Finally, we propose a straightforward nomenclature system for the members of the mouse kinesin superfamily.

Detection of HTLV type I provirus by in situ polymerase chain reaction in mouthwash mononuclear cells of HAM/TSP patients and HTLV type I carriers.

Molecular studies have revealed the presence of HTLV-I provirus DNA in saliva of HTLV-I-infected subjects. However, cellular localization has not been determined. In the present study, we have used in situ PCR technique to study saliva-associated cells for localization of HTLV-I proviral DNA. We found that HTLV-I proviral DNA was present in the nuclei and cytoplasm of salivary lymphocytes in five (71%) of seven HTLV-I-seropositive subjects. The percentage of infected cells in positive mouthwash samples ranged from 0.5 to 2%. None of the HTLV-I-negative patients had HTLV-I provirus in saliva. The localization of HTLV-I provirus DNA suggests that salivary lymphocytes can serve as vector for HTLV-I infection through saliva.

The main HTLV-I-harboring cells in the muscles of viral carriers with polymyositis are not macrophages but CD4+ lymphocytes.

We have analyzed muscle biopsy specimens from polymyositis patients who are also positive for human T cell lymphotropic virus type I (HTLV-I) using both immunohistochemistry for surface antigens of lymphocytes and macrophages and in situ polymerase chain reaction for HTLV-I proviral DNA on the same sections. We found HTLV-I in CD4+ cells but not in macrophages. This finding suggests that most of the HTLV-I-containing CD4+ cells are not macrophages but lymphocytes.

[Effect of mazindol on obesity induced by administration of gold thioglucose].

The present experiments were carried out to elucidate the effect of mazindol feeding on obese mice made by gold-thioglucose injection. Mazindol was added to the diet at the level of 0.5, 2, 10 mg/kg body weight. It was found that oral administration of mazindol reduced the body weight gain and perimetrial adipose tissue weights increased in GTG-obese mice. Decreased adipose tissue weights were correlated with the decreased level of size and volume of fat cells. Basal lipolytic activity and adrenaline-induced lipolysis were also significantly decreased in mazindol groups as compared to those in GTG-obese mice that were not administered mazindol. These results indicate that the weight reduction induced by mazindol administration might not be due to increase in fat mobilization. The increased level of liver and serum lipid induced by GTG-obesity was also found to be improved by mazindol. Scanning electron micrographs indicated that the villous width of the small intestine were significantly smaller in the mazindol group that those in the GTG-obese group. Sucrase and esterase activities of the small intestine were also decreased by mazindol feeding as compared to those in the GTG-obese mice. based on these results mechanisms of action of mazindol were discussed.