Perturbation of secretory Ig A in saliva and its daily variation by academic stress

Objectives Several studies have reported that the secretory immunoglobulin A (S-IgA) concentration in saliva is an indicator of psychological stress. The aim of this study was to clarify the relationship between S-IgA and the stress from academic examinations. Methods S-IgA levels in 10 medical student volunteers from the second year course between May 4 and July 13, 2000 were examined using the ELISA method. Results There was a tendency for S-IgA in saliva to be higher on the day before academic examinations and during them, and lower on the days between these examinations. Conclusions It may be possible to use this measurement to monitor psychological stress in students and workers. Second year medical student in the year 2000.     

Synaptic organization of the rat parafascicular nucleus,with special reference to its afferents from the superior colliculus and the pedunculopontine tegmental nucleus

The synaptic organization of afferents to the parafascicular nucleus (Pf) of the thalamus was studied in rats. In the Pf, three types of axon terminals were identified: the first type was a small terminal with round synaptic vesicles forming an asymmetric synapse, the second type was a large terminal with round synaptic vesicles forming an asymmetric synapse, and the third type was a terminal with pleomorphic vesicles forming a symmetric synapse. They were named SR, LR and P boutons, respectively. In order to determine the origin of these axon terminals, biotinylated dextran amine (BDA) was injected into the main afferent sources of the Pf, the superior colliculus (SC) and the pedunculopontine tegmental nucleus (PPN). Axon terminals from the SC were both SR and LR boutons which made synaptic contacts with somata and dendrites. PPN afferents were SR boutons, which made synaptic contacts with somata and smaller dendrites. Double-labeled electron microscopic studies, in which a retrograde tracer (wheat germ agglutinin conjugated to horseradish peroxidase: WGA-HRP) was injected into the striatum and an anterograde tracer (BDA) into the SC revealed that SC afferent terminals made synapses directly with Pf neurons that projected to the striatum. Another experiment was performed to find out whether two different afferents converged onto a single Pf neuron. To address this question, two different tracers were injected into the SC and PPN in a rat. Electron microscopically, both afferent terminals from the SC and PPN made synaptic contacts with the same dendrite. Our results prove that a single neuron of the rat Pf received convergent projections from two different sources.     

Ependymal cell reactions in spinal cord segments after compression injury in adult rat

Recently, it has been suggested that neural stem cells and neural progenitor cells exist in the ependyma that forms the central canal of the spinal cord. In this study, we produced various degrees of thoracic cord injury in adult rats using an NYU-weight-drop device, assessed the degree of recovery of lower limb motor function based on a locomotor rating scale, and analyzed the kinetics of ependymal cell proliferation and differentiation by proliferating cell nuclear antigen (PCNA), nestin, glial fibrillary acidic protein (GFAP), or GAP-43 immunostaining. The results showed that the time course of the ependymal cell proliferation and differentiation reactions differed according to the severity of injury, and that the responses occurred not only in the neighborhood of the injury but in the entire spinal cord. An increase in the locomotor rating score was related to an increase in the number of PCNA-positive cells, and the differentiation of ependymal cells into reactive astrocytes was involved in injury repair. No apoptotic cells in the ependyma were detectable by the TUNEL method. These results indicate that the ependymal cells of the spinal central canal are themselves multipotent, can divide and proliferate according to the severity of injury, and differentiate into reactive astrocytes within the ependyma without undergoing apoptosis or cell death.     

Generation of free radicals and/or active oxygen by light or laser irradiation of hydrogen peroxide or sodium hypochlorite

Generation of free radical and/or active oxygen by light or laser irradiation of hydrogen peroxide (H2O2) or sodium hypochlorite (NaClO), which have been used for tooth whitening or root canal irrigation, was investigated using electron spin resonance spectroscopy combined with a spin-trapping technique. When H2O2 was exposed to light or laser radiation, the amount of hydroxyl radical generated changed according to the concentration of H2O2 and irradiation time. The amount of 5,5-dimethyl-1-pyrrolidone-(2)-oxyl-(1) (DMPO-X) also changed in accordance with irradiation time. The amounts of hydroxyl radical generated from H2O2 after irradiation were in the order: plasma lamp > halogen lamp > He-Ne laser > Yellow He-Ne laser. On the other hand, the amounts of DMPO-X generated from NaClO after irradiation were in the order: plasma lamp > Yellow He-Ne laser > halogen lamp > He-Ne laser.     

Impact of Prol2Ala variant in the peroxisome proliferator-activated receptor (PPAR) gamma2 on obesity and insulin resistance in Japanese Type 2 diabetic and healthy subjects

The peroxisome proliferator-activated receptor (PPAR) gamma is an important regulator of adipocyte differentiation and a modulator of intracellular insulin-signaling events. We examined the roles of the Pro12Ala variant of PPAR gamma2 in obesity and insulin resistance in 402 Japanese patients with type 2 diabetes and 116 control subjects. Among the diabetes subjects, the Pro12Pro homozygotes showed significantly higher body mass index (BMI) than those with the Pro12Ala variant (p = 0.020), while there was no association between genotype and BMI in the controls. Furthermore, diabetic subjects with Pro12Pro showed significantly higher fat body mass index (FBMI) than those with Pro12Ala (p = 0.016), while no association between genotype and lean body mass index (LBMI) was observed. Regarding insulin resistance, there was no difference in the HOMA index or in clamp index between Pro12Ala and Pro12Pro variants. These data suggest that the Pro12Ala polymorphism of PPAR gamma2 does not influence insulin resistance but body composition in Japanese diabetic subjects.     

MEGF1/fat2 proteins containing extraordinarily large extracellular domains are localized to thin parallel fibers of cerebellar granule cells

The MEGF1 (protein 1 with multiple EGF-like domains) gene, which was identified using motif-trap screening, encodes an extraordinarily large protein containing two EGF-like and 34 cadherin motifs. In situ hybridization analysis revealed that the MEGF1 gene was specifically expressed in granule cells of the cerebellum. Interestingly, in the developing cerebellum, granule cells in the inner external germinal layer and migrating granule cells expressed MEGF1 mRNA, whereas proliferating cells in the outer external germinal layer did not express MEGF1 mRNA. Expression levels in the internal granule cell layer peaked during the third postnatal week and remained considerably high in the adult cerebellum. MEGF1 protein was detected in only the cerebellum as a single 480-kDa band by immunoblot analyses using polyclonal antibodies against either the N-terminal or the C-terminal region of MEGF1 protein. Using light and electron microscopic immunocytochemistry, specific immunostaining of the MEGF1 protein was observed in the molecular layer of the cerebellum, suggesting that MEGF1 protein was localized in the parallel fibers of cerebellar granule cells. This was corroborated by results from experiments using primary dispersed cultures of cerebellar granule cells and cerebellar microexplant cultures. The homophilic interaction of MEGF1 proteins was confirmed with both a cell aggregation assay and an in vitro copurification assay. Based on these results, a novel function of the enormous protocadherins in cerebellar development, namely, the modulation of the extracellular space surrounding parallel fibers during development, was proposed.     

Flexion-distraction injuries in the thoracolumbar spine: an in vitro study of the relation between flexion angle and the motion axis of fracture

A new concept, the motion axis of fracture (MAF), which is defined as the transitional point from anterior compressive to posterior splitting failure on a lateral radiograph, has provided a true understanding of the mechanisms of flexion-distraction injuries in clinical cases. This study was designed to produce in vitro injuries that have MAFs and to clarify the relation between the flexion angle and the MAF location. Adolescent porcine thoracolumbar spines were exposed to a vertical compressive load to failure at three different flexion angles and then examined radiographically. The MAF location was recorded as the distance from the anterior border to the MAF expressed as a percentage of the anteroposterior diameter of the vertebral body. All specimens showed similar injuries, with MAFs consisting of anterior compression fractures in the vertebral bodies and posterior disruptions. A significant negative correlation emerged between the flexion angle and the MAF location (r = -0.890; p < 0.0001). These results suggest that even a vertical compressive load contributes to the production of a flexion-distraction injury with an MAF in the thoracolumbar spine. They also indicate that the flexion angle of the spine at which the vertical compressive load is applied is an important factor in determining the MAF location; that is, the larger the flexion angle, the more anterior the MAF.     

Involvement of transporters in the hepatic uptake and biliary excretion of valsartan, a selective antagonist of the angiotensin II AT1-receptor, in humans.

Valsartan is a highly selective angiotensin II AT1-receptor antagonist for the treatment of hypertension. Valsartan is mainly excreted into the bile in unchanged form. Because valsartan has an anionic carboxyl group, we hypothesized that a series of organic anion transporters could be involved in its hepatic clearance. In this study, to identify transporters that mediate the hepatic uptake and biliary excretion of valsartan and estimate the contribution of each transporter to the overall hepatic uptake and efflux, we characterized its transport using transporter-expressing systems, human cryopreserved hepatocytes, and Mrp2-deficient Eisai hyperbilirubinemic rats (EHBRs). Valsartan was significantly taken up into organic anion-transporting polypeptide (OATP) 1B1 (OATP2/OATP-C)- and OATP1B3 (OATP8)-expressing HEK293 cells. We also observed saturable uptake into human hepatocytes. Based on our estimation, the relative contribution of OATP1B1 to the uptake of valsartan in human hepatocytes depends on the batch, ranging from 20 to 70%. Regarding efflux transporters, the ratio of basal-to-apical transcellular transport of valsartan to that in the opposite direction in OATP1B1/MRP2 (multidrug resistance-associated protein 2) double transfected cells was the highest among the three kinds of double transfectants, OATP1B1/MRP2, OATP1B1/multi-drug resistance 1, and OATP1B1/breast cancer resistance protein-expressing MDCKII cells. We observed saturable ATP-dependent transport into membrane vesicles expressing human MRP2. We also found that the elimination of intravenously administered valsartan from plasma was markedly delayed, and the biliary excretion was severely impaired in EHBR compared with normal Sprague-Dawley rats. These results suggest that OATP1B1 and OATP1B3 as the uptake transporters and MRP2 as the efflux transporter are responsible for the efficient hepatobiliary transport of valsartan.     

Developmental role of static, dynamic, and contextual cues in speech perception.

The purpose of the current study was to examine the role of syllable duration context as well as static and dynamic acoustic properties in child and adult speech perception. Ten adults and eleven 4-5-year-old children identified a syllable as [ba] or [wa] (stop-glide contrast) in 3 conditions differing in synthetic continua. The 1st condition tested the potential existence of the syllable duration effect in young children, whereas the 2nd and 3rd conditions examined the developmental role of static and dynamic cues, respectively, as related to syllable duration context effects. In the 1st condition, the 1st and 2nd formant transition duration of stimuli varied from those appropriate for [ba] to those appropriate for [wa]. For the 2nd condition, a static burst was added to Condition 1 stimuli. For the 3rd condition, the dynamic transition frequency and transition duration for the first 3 formants varied as appropriate for [ba] and [wa]. In each condition, 3 syllable context durations of 105 ms, 170 ms, and 315 ms were tested. The results indicated that syllable duration context effects were present across all conditions for both adults and children. However, the adults and children did differ in the 3rd condition, in which both the transition frequency and the transition duration were altered. Thus, children used the dynamic formant transitions differently than adults when transition frequency was varied along with transition duration. These findings show that children have a bias toward formant transitions and indicate that young children of 4-5 years of age attend differently than adults to changes in dynamic cues such as formant transitions, as predicted by the developmental cue weighting shift model.     

Immunohistochemical Study of Serum Proteins in Normal and Cadmium-Treated Mouse Testis by in vivo CryotechniqueImmunohistochemical Study of Serum Proteins in Normal and Cadmium-Treated Mouse Testis by in vivo Cryotechnique

Objective To investigate time-dependent changes of serum proteins permeability in the normal and cadmium（Cd）-treated mouse testis, reflecting tight junctional （TJ） barriers of Sertoli cells Methods The serum proteins, albumin and immunoglobulin-G（IgG）, in the seminiferous tubules were firstly immobilized by the “in vivo cryotechnique”, in which the dynamic blood circulation was always kept. The cryofixed testicular tissues were then processed for the freeze-substitution method, and embedded in the paraffin wax. Serial sections of 5μm thickness were immunostained by anti-mouse albumin or IgG antibody with peroxidase immunostaining, and also stained with hematoxylin-eosine （HE）for morphological observation. Results In normal seminiferous tubules, albumin immunoreaction products were localized around peritubular myoid cells and among Leydig cells, as well as in blood vessels. They were also localized as arch-like patterns around some spermatogonia in basal compartments. The number of the immunopositive arch structures was different according to developmental stages of the seminiferous cycle, judging from the arrangement of germ cells by HE-staining. The patterns of localization of IgG immunostaining in normal mouse testis were similar to that of albumin. In 24 h after Cd-treatment, some enlarged spaces and vesicular formation in the seminiferous epithelium were observed on the paraffin sections by HE-staining. The albumin or IgGimmunolocalization was seen not only in the basal compartments, but also in the adluminal compartments between Sertoli.cells and germ cells. Conclusion The structural changes of inter-Sertoli TJ barriers in vivo, such as different immunostaining patterns of serum proteins between the normal and Cd-treated mouse seminiferous tubules, could be clearly detected by the “in vivo cryotechnique” with albumin or IgG immunohistochemistry.