Ontogeny of plasma cells in the early rat yolk sac

The present study investigated the development of plasma cells in the early rat yolk sac (days 10-16 of gestation) by light microscopy, transmission electron microscopy, immunoelectron microscopy, and indirect immunofluoresce techniques. Cells delineating the morphology of plasma cells in the yolk sac were observed as early as 12 days of embryonic life. As for positive immune staining for the intra-cytoplasmic immunoglobulin (Ig) production (IgA, IgM and IgG), the intensity of the immune staining was very weak on days 10 and 11 of gestation, while it turned very dense on day 12 of gestation. At 14 days of gestation, the number of positive cells was markedly reduced. Immunoelectron microscopy visualized products of the immune reaction in cisterns of the rough endoplasmic reticulum. Conventional electron microscopic examination of 12, 13, and 16-day yolk sacs confirmed the development and differentiation of plasma cells with their well-known ultrastructural features, making this the first study to demonstrate these in the early rat yolk sac. The development of plasma cells in the early yolk sac implies the ability of the yolk sac to effect a humoral immune response at this stage of fetal life. The probable role of plasma cells in the yolk sac is also discussed.     

Expression of estrogen receptor alpha (ER alpha) in the rat temporomandibular joint

Numerous epidemiological studies have pointed out a higher frequency of temporomandibular disorder (TMD) in women than in men, which indicates the involvement of a sex hormone, such as estrogen, in the pathogenesis of TMD. Although estrogen is known to play pivotal roles in osteoarthrosis or rheumatoid arthritis in systemic joints, there have been few reports about the role of estrogen in the temporomandibular joint (TMJ). The effect of estrogen is generally mediated by the estrogen receptors (ERs) ER alpha (the predominant type) and ER beta. In this study we examined the expression of ER alpha protein and mRNA in the TMJ of adult male rats by immunocytochemistry and in situ hybridization histochemistry. Intense ER alpha immunoreactivity was localized in the synovial lining cells, stromal cells in the articular disc, and chondrocytes in the TMJ. These ER alpha-immunopositive synovial lining cells are characteristic of cytoplasmic processes identified with confocal and immunoelectron microscopy, which indicates that they are synovial type B cells. In situ hybridization histochemistry confirmed intense signals for ER alpha in the synovial lining cells and the sublining fibroblasts at mRNA levels. The nuclei of chondrocytes showed an intense immunoreaction for ER alpha in the maturative and hypertrophic layers of the articular cartilage. In addition to the nuclear localization of ER alpha, a weak immunoreaction appeared in the cytoplasm of some ER alpha-positive cells. These findings support the hypothesis that TMJ tissue-at least in the male rat-has the potential to be an estrogen target tissue.     

Isolation,characterization and chromosomal mapping of an actin gene from the primitive red alga Cyanidioschyzon merolae

Based on the results of cytological studies, it has been assumed that Cyanidioschyzon merolae does not contain actin genes. However, Southern hybridization of C. merolae cell-nuclear DNA with a yeast actin-gene probe has suggested the presence of an actin gene in the C. merolae genome. In the present study, an actin gene was isolated from a C. merolae genomic library using a yeast actin-gene probe. The C. merolae actin gene has no intron. The predicted actin is composed of 377 amino acids and has an estimated molecular mass of 42003 Da. Southern hybridization indicated that the C. merolae genome contains only one actin gene. This gene is transcribed at a size of 2.4 kb. When Southern hybridization was performed with C. merolae chromosomes separated by pulsed-field gel electrophoresis, a band appeared on unseparated chromosomes XI and XII. A phylogenetic tree based on known eucaryote actin-gene sequences revealed that C. merolae diverged after the division of Protozoa, but before the division of Fungi, Animalia and Chlorophyta.     

Silicon contents in normal, fatty streaks and atheroma of human aortic intima: its relationship with glycosaminoglycans

The silicon (Si) content and glycosaminoglycans (GAG) of normal, fatty streaks and atheroma of human aortic intima was measured. The Si content in fatty streaks and/or atheroma was significantly higher than in normal human aortic intima (P less than 0.05). The GAG content in human aortic intima was inversely correlated with the severity of atherosclerosis as described in many reports. However, the percentage composition of dermatan sulphate (DS) in total GAG was found to increase with the advance of atherosclerosis, and was significantly higher than that in normal and fatty streaks (P less than 0.001, P less than 0.01, respectively). In human aortic intima, a significant negative correlation was seen between Si content and the content of each GAG except GlcUA-GalNAc-6-sulphate (CS-6-S), and a significant positive correlation was noted between Si content and the content of each lipid. Interestingly, the percentage composition of DS in total GAG showed a significant positive correlation with Si content in human aortic intima (r = 0.603, P less than 0.005). These results suggest the increase in Si in the aortic intima is related to the occurrences and/or progression of atherosclerosis, whether primary or secondary.     

High intensity exercise decreases global brain glucose uptake in humans

Physiological activation increases glucose uptake locally in the brain. However, it is not known how high intensity exercise affects regional and global brain glucose uptake. The effect of exercise intensity and exercise capacity on brain glucose uptake was directly measured using positron emission tomography (PET) and [¹⁸F]fluoro-deoxy-glucose ([¹⁸F]FDG). Fourteen healthy, right-handed men were studied after 35 min of bicycle exercise at exercise intensities corresponding to 30, 55 and 75% of     on three separate days. [¹⁸F]FDG was injected 10 min after the start of the exercise. Thereafter exercise was continued for another 25 min. PET scanning of the brain was conducted after completion of the exercise. Regional glucose metabolic rate (rGMR) decreased in all measured cortical regions as exercise intensity increased. The mean decrease between the highest and lowest exercise intensity was 32% globally in the brain (38.6 ± 4.6 versus 26.1 ± 5.0 μmol (100 g)⁻¹ min⁻¹, P < 0.001). Lactate availability during exercise tended to correlate negatively with the observed brain glucose uptake. In addition, the decrease in glucose uptake in the dorsal part of the anterior cingulate cortex (37% versus 20%, P < 0.05 between 30% and 75% of     ) was significantly more pronounced in subjects with higher exercise capacity. These results demonstrate that brain glucose uptake decreases with increase in exercise intensity. Therefore substrates other than glucose, most likely lactate, are utilized by the brain in order to compensate the increased energy needed to maintain neuronal activity during high intensity exercise. Moreover, it seems that exercise training could be related to adaptive metabolic changes locally in the frontal cortical regions.     

Analgesic action of loperamide,an opioid agonist,and its blocking action on voltage-dependent Ca2+ channels

We investigated the relationship between the antinociceptive effect of the opiate agonist loperamide at the spinal level and its inhibitory effect on calcium influx. Intrathecal administration of loperamide showed a significant antinociceptive effect in the formalin test, which was not prevented by naloxone. On the other hand, no significant effects were observed by nicardipine, an L-type specific blocker, or by BAY K8644, an L-type specific agonist, suggesting no significant role of L-type calcium channels in nociceptive signal transduction. Loperamide suppressed the calcium influx in dorsal root ganglion neurons. As the antinociceptive effect of loperamide was not affected by naloxone or other calcium channel blocking toxins, and loperamide showed a direct inhibitory effect on calcium-influx, the analgesic effect of intrathecally injected loperamide might be due to its blockade of the voltage-dependent calcium channels at the terminals of the primary afferent fibers.     

Clinical studies on cefminox in pediatric field

Clinical studies on cefminox (CMNX, MT-141) were conducted and the following results were obtained. Twelve cases of bacterial infections were treated with CMNX with a satisfactory result of "excellent" in 9 and "good" in 3. Antibacterial activity was examined in 7 cases. Pathogenic organisms which were S. aureus, beta-Streptococcus, H. influenzae, S. pneumoniae and P. morganii were eradicated in all the cases. Mean maximum serum concentrations of CMNX after intravenous injection of 10, 20 and 40 mg/kg were 54.5 mcg/ml, 102.3 mcg/ml and 202.4 mcg/ml, respectively which were obtained 15 minutes after each injection. Mean half-lives of each dose group were 1.60, 1.13 and 1.51 hours, respectively. Mean urinary excretion rates of CMNX at 6 hours after intravenous injection in 10, 20, 30 and 40 mg/kg groups were 73.5%, 80.9%, 92.6% and 66.5%, respectively. Side effects were not observed clinically, but anemia in 1 case and eosinophilia in 2 cases were noted in laboratory examination.     

Electrophysiological study on limb myokymia in three women.

Physiological studies on three women with limb myokymia were carried out. The patients had diabetic neuropathy, neuromyotonia, and autonomic polyneuropathy, respectively. The EMG discharge pattern, coincident with myokymia, in a patient with myokymia and neuromyotonia differed from those with myokymia without neuromyotonia. In only the first patient did the electrical stimulation of nerves evoke "late repetitive response" (LRR), which resembled the wave forms of the myokymic discharge. Epidural and peripheral nerve blocks abolished myokymia in the first and second cases, but peripheral nerve block was without effect in the third patient. These findings indicate that myokymia originates in multiple sites of alpha motor neurons and that the pathophysiology may vary.