Melanin pigmentation in mammalian skin and its hormonal regulation

Cutaneous melanin pigment plays a critical role in camouflage, mimicry, social communication, and protection against harmful effects of solar radiation. Melanogenesis is under complex regulatory control by multiple agents interacting via pathways activated by receptor-dependent and -independent mechanisms, in hormonal, auto-, para-, or intracrine fashion. Because of the multidirectional nature and heterogeneous character of the melanogenesis modifying agents, its controlling factors are not organized into simple linear sequences, but they interphase instead in a multidimensional network, with extensive functional overlapping with connections arranged both in series and in parallel. The most important positive regulator of melanogenesis is the MC1 receptor with its ligands melanocortins and ACTH, whereas among the negative regulators agouti protein stands out, determining intensity of melanogenesis and also the type of melanin synthesized. Within the context of the skin as a stress organ, melanogenic activity serves as a unique molecular sensor and transducer of noxious signals and as regulator of local homeostasis. In keeping with these multiple roles, melanogenesis is controlled by a highly structured system, active since early embryogenesis and capable of superselective functional regulation that may reach down to the cellular level represented by single melanocytes. Indeed, the significance of melanogenesis extends beyond the mere assignment of a color trait.     

In situ localization of tau mRNA in developing rat brain

A microtubule-associated protein, tau, promotes microtubule assembly, forms characteristic short cross-bridges (less than 20 nm) between microtubules, and switches isoforms from juvenile to adult at the end of the first postnatal week in the rat brain. The developmental expression of tau was studied in rat central nervous system, mainly the cerebrum and cerebellum, by in situ hybridization. Tau mRNAs were localized in a wide variety of neural cells. The expression of tau mRNAs in the spinal cord appeared to precede that in the brain, and the expression in the brainstem appeared to precede that in the cerebral cortex and cerebellum. On neural cells throughout the cortical plate of the cerebral cortex, tau mRNAs were expressed in large amounts during the first postnatal week, but by the third postnatal week the expression had become reduced. In the cerebellum, tau mRNAs were enriched in granule cells. The expression in the internal granular layer peaked during the second and third postnatal weeks, and the relatively high level of expression persisted to young adulthood. Thin section transmission electron microscopic study revealed that the proportion of neighboring microtubules in parallel fiber axons of cerebellar granule cells with the distance less than 20 nm was as low as 10% at the end of the first postnatal week, but this proportion increased to as high as 35% at the end of the second postnatal week. Northern blot analysis showed that tau mRNAs were congruent to 6 kb as was reported previously, and those detected in the first postnatal week were three- to five-fold more abundant and approximately 0.2 kb smaller than those detected in the second or third postnatal weeks. The data suggest that (a) tau mRNAs are abundantly expressed in a wide variety of neurons in the central nervous system at the stage of neurite formation, and (b) tau mRNAs are expressed in more basal levels at later stages, but may be important in the formation and maintenance of characteristic microtubule bundles typically found in parallel fiber axons and in other axons.     

Fermented grain products, production, properties and benefits to health

Fermented foods such as Japanese traditional food “miso (fermented soy bean paste)” have been shown to be rich source of micronutrients with the potential to prevent various human diseases. We have introduced effects of a new dietary supplement of fermented grain foods mixture containing extracts from wheat germ, soybeans, rice bran, tear grass, sesame, wheat, citrus lemon, green tea, green leaf extract and malted rice under the trade name of antioxidant biofactor (AOB). Chemical analysis of AOB shows the presence of various phenolic compounds (catechins, rutin, genistin, daidzin, etc.). AOB has strong antioxidant properties and additional biological effects, which might be of importance in context with the prevention of degenerative diseases. This paper focuses on the effect of supplementing AOB in various animal models and humans.     

Selective expression of L-serine synthetic enzyme 3PGDH in schwann cells, perineuronal glia, and endoneurial fibroblasts along rat sciatic nerves and its upregulation after crush injury

Non-essential amino acid L-serine functions as a highly potent, glia-derived neurotrophic factor, because it is a precursor for syntheses of proteins, other amino acids, membrane lipids, and nucleotides, and also because its biosynthetic enzyme 3-phosphoglycerate dehydrogenase (3PGDH) is preferentially expressed in particular glial cells within the brain. Here we pursued 3PGDH expression in peripheral nerves and its change after crush injury. In the pathway of rat sciatic nerves, 3PGDH was selectively expressed in non-neuronal elements: Schwann sheaths and endoneurial fibroblasts in sciatic nerves, satellite cells in dorsal root ganglia, and astrocytes and oligodendrocytes in the spinal ventral horn. In contrast, 3PGDH was immunonegative in axons, somata of spinal motoneurons and ganglion cells, and endoneurial macrophages. One week after crush injury, 3PGDH was upregulated in the distal segment of injured nerves, where 3PGDH was intensified in activated Schwann cells and fibroblasts. 3PGDH was still negative in activated macrophages, which were instead associated or surrounded by activated Schwann cells with intensified 3PGDH. These results suggest that in the peripheral nervous system, these non-neuronal cells synthesize and may supply L-serine to satisfy metabolic demands for maintenance and regeneration of peripheral nerves and for proliferation and activation of macrophages upon nerve injury.     

Effects of added bioactive glass on the setting and mechanical properties of resin-modified glass ionomer cement

In this study, the effects of added bioactive glass on the basic setting properties of a commercially available resin-modified glass ionomer cement were investigated with respect to setting time, mechanical strength, and setting mechanism. It was found to be clinically acceptable whether the setting time was extended or shortened depending on the type of bioactive glass added. The compressive strength of the set cement containing the bioactive glass decreased and was much higher when compared with the conventional type glass ionomer cement containing bioactive glass. The Fourier-transform infrared and 13C CP/MAS-NMR spectroscopies revealed that the extent of the acid-base reaction was larger in the cements containing bioactive glass than in the commercial resin-modified glass ionomer cement because of its high basicity in the bioactive glass. The 27Al MAS-NMR showed that crosslinking of the carboxylates in the polymeric acid by Al proceeded less in the cement containing the bioactive glass.     

An algorithm for mapping the catheter tip position on a fluorograph to the three-dimensional position in magnetic resonance angiography volume data

This paper proposes an algorithm which maps the position of a catheter tip on a fluorograph to the 3D position in magnetic resonance angiography (MRA) data. This algorithm was assessed for its accuracy. We designed an algorithm consisting of a registration step and a recognition step. The registration step registers MRA and fluorography data using a digital subtraction angiography (DSA) image. The recognition step recognizes the position in the MRA data corresponding to the catheter tip position on a fluorograph. We checked the accuracy of the recognition step by employing an artificial data set consisting of 3D image data (64 x 64 x 64 matrix) and its projection image (92 x 92 matrix) and the accuracy of the registration step with the aid of three of the 3D time-of-flight MRA data sets (256 x 256 matrix and 60 slices) and their projection images in the form of DSA images. The accuracy of the recognition step depended upon that of the registration. When there was no misregistration, all of the mean errors were less than 0.2 mm. The mean errors of the registration step were 0.273 mm and 0.226 mm, respectively, for the longitudinal shift along the X and Y axes, 0.478 degrees, 1.203 degrees and 0.208 degrees, respectively, for the rotation angles around the X, Y and Z axes and 0.020 times for the magnification. The mean image error between the projection image of the registered MRA data and that of the MRA data which were employed as the DSA image was 0.034 mm.     

Infection of macaques with chimeric simian and human immunodeficiency viruses containing Env from subtype F

Chimeric simian and human immunodeficiency viruses (SHIVs) are useful for investigating the pathogenicity of human immunodeficiency virus (HIV-1) and to develop an anti-HIV-1 vaccine. We attempted to construct SHIVs containing Env from various subtypes, because almost all SHIVs which have been reported so far have Env from HIV-1 that belongs to subtype B. Two infectious SHIVs containing Env from two strains of HIV-1, CMR304 and CMR306, which belong to subtype F and A, respectively, were newly obtained. These SHIVs essentially showed a coreceptor usage and a neutralization pattern that were similar to those of the parental HIV-1s. In macaque PBMC, SHIVcmr304 replicated with kinetics similar to that of prototypic SHIV-NM-3rN with HIV-1 NL432 Env, but SHIVcmr306 replicated poorly. Inoculation of four rhesus macaques with SHIVcmr304 resulted in an increase of plasma viral load in all the macaques, though viral RNA copies were 100-fold lower than that in the infection with NM-3rN. This SHIV containing Env from HIV-1 subtype F will be a valuable source for the analysis of HIV-1 subtype F and the evaluation of vaccine candidates as a genetically divergent challenge virus.     

A case of the right subclavian artery as the last branch of the aortic arch in the human fetus and a new classification on these variations

An anomalous case of the right subclavian artery arising from the aortic arch as the last branch, in which the first branch was the right common carotid, the second the left common carotid and the third the left subclavian artery, was found in a 10 months human fetus among 173 fetuses. The right subclavian artery arose from the posterior wall of the aortic arch at the level of the Th4 and passed obliquely between the esophagus and the thoracic vertebrae. The right and the left vertebral arteries arising from the subclavian arteries on the same side entered the transverse foramen of the C6 of each side. This case belonged to type G of Adachi's classification and as well type 5 of Holzapfel's. The present authors wish to offer a new trial classification on these variations, including the origins and numbers of the vertebral arteries, by investigating many original reports in Japanese, as follows: 1) A new classification is fixed on the basis of the type G and H of Adachi-Williams et al.-Nakagawa in the classification of the branching types of the aortic arch. The type G represents that the right common carotid, the left common carotid, the left subclavian and the right subclavian arteries arise from the aortic arch in this order. The type H represents that the bicarotid trunk, the left subclavian and the right subclavian arteries arise from the aortic arch. 2) When the left vertebral artery arising from the aortic arch is found in the type G and H, "C" is prefixed G or H, as type CG, type CH. 3) When the right vertebral artery arising from the right common carotid artery is found, a prime mark, "', is put on G or H, as type G', type H'. 4) In order to represent a compound type of the above 2) and 3), both "C" and "' are put, as type CG', type CH'. 5) When the bilateral vertebral arteries arising from the respective subclavian artery are found in the above 2), 3) and 4) "2" postfixed "C" and the prime mark "', as type G'2, type C2G, type CG'2, type C2G', type C2G'2, type H'2, type C2H, type CH'2, type C2H', type C2H'2. According to the above new classification, Adachi's type G can be arranged into 18 branching types. This classification may be helpful and sufficient to provide more than 100 cases of the type G and H reported on Japanese.(ABSTRACT TRUNCATED AT 250 WORDS)