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Antimicrobial photodynamic therapy (aPDT) using aminolaevulinic acid (ALA) is a promising alternative to antibiotic therapy. ALA administration induces protoporphyrin IX (PpIX) accumulation in bacteria, and light excitation of the accumulated PpIX generates singlet oxygen to bacterial toxicity. Several factors, including drug administration and light irradiation conditions, contribute to the antibiotic effect. Such multiple parameters should be determined moderately for effective aPDT in clinical practice.A mathematical model to predict bacterial dynamics in ALA-aPDT following clinical conditions was constructed. Applying a pharmacokineticspharmacodynamics (PK-PD) approach, which is widely used in antimicrobial drug evaluation, viable bacteria count by defining the bactericidal rate as the concentration of singlet oxygen produced when PpIX in bacteria is irradiated by light.The in vitro experimental results of ALA-aPDT for Pseudomonas aeruginosa demonstrated the PK-PD model validity. The killing rate has an upper limit, and the lower power density for a long irradiation time can suppress the viable bacteria number when the light dosages are the same.This study proposed a model of bacterial viability change in ALA-aPDT based on the PK-PD model and confirmed, by in vitro experiments using PA, that the variation of bacterial viability with light-sensitive substance concentration and light irradiation power densities could be expressed. Further validation of the PK-PD model with other gram negative and gram positive strains will be needed.

It is essential to consider the fluidity of a debris flow front when calculating its impact. Here we flume-tested mono-granular and bi-granular debris flows and compared the results to those of numerical simulations. We used sand particles with diameters of 0.29 and 0.14 cm at two mixing ratios of 1:1 and 3:7. Particle segregation was recorded with a high-speed video camera. We evaluated the fronts of debris flows at 0.5-second intervals. Then we numerically simulated one-dimensional debris flows under the same conditions and used the mean particle diameter when simulating mixed-diameter flows. For the mono-granular debris flows, the experimental and simulated results showed good agreement in terms of flow depth, front velocity, and flux. However, for the bi-granular debris flows, the simulated flow depth was less, and both the front velocity and flux were greater than those found experimentally. These differences may be attributable to the fact that the dominant shear stress was caused by the concentration of smaller sediment particles in the lower flow layers; such inverse gradations were detected in the debris flow bodies. Under these conditions, most shear stress is supported by smaller particles in the lower layers; the debris flow characteristics become similar to those of mono-granular flows, in contrast to the numerical simulation, which incorporated particle segregation with gradually decreasing mean diameter from the front to the flow body. Consequently, the calculated front velocities were underestimated; particle segregation at the front of the bi-granular debris flows did not affect fluidity either initially or over time.

The development of robust and reactive chiral catalysts is a fundamental aim in asymmetric catalysis, and crucial for providing efficient methods for synthesizing chiral molecules. Chiral paddle-wheel bimetallic complexes provide a highly tunable chiral environment in rhodium-catalysed asymmetric carbene/nitrene transfer reactions and Lewis acid-catalysed reactions. Chiral paddle-wheel complexes having other transition metals as the reactive metal centre, however, have not yet been identified in asymmetric catalysis. Here, we report the synthesis, structures and high catalytic performances of chiral paddle-wheel diruthenium complexes. The cationic chiral diruthenium complex [Ru2((S)-BPTPI)4]+ exhibited remarkable reactivity as a Lewis acid catalyst for asymmetric hetero-Diels–Alder reactions, achieving a turnover number of up to 1,880,000 with high enantioselectivity (>90% e.e.). The chiral diruthenium complexes also exhibited good reactivity and high enantioselectivity in C–H amination and cyclopropanation reactions under oxidizing conditions, indicating their high tolerance towards oxidation. Our results reveal the chiral paddle-wheel diruthenium scaffold as a promising platform for asymmetric catalysis. The development of chiral catalysts is of fundamental importance in asymmetric catalysis. Now, chiral paddle-wheel diruthenium complexes are reported that are stable under oxidizing conditions and effective in asymmetric C–C and C–N bond-forming reactions with turnover numbers of up to 1,880,000.

Nodule formation is a two-step cell-mediated immune response that is elicited by the cytokine spätzle1. Spätzle1 is activated within 30 s of invasion by microorganisms via an extracellular signaling pathway that consists of pathogen-associated molecular pattern recognition receptors, C-type lectins, and serine proteases. Here, we investigated a hemocyte molecule that is involved in eliciting the first step of nodule formation. BmToll10-3 was one of 14 Toll homologs identified in the silkworm Bombyx mori; it is an ortholog of Spodoptera exigua Toll. Previous research suggested that SeToll elicits nodule formation, but no evidence was presented to indicate whether SeToll elicited the first or second step of nodule formation. Reverse transcription-polymerase chain reaction and immunostaining confirmed that BmToll10-3 is expressed in granulocytes. To determine whether BmToll10-3 is involved in eliciting the first step of nodule formation, we tested an antiserum raised against BmToll10-3 in a nodule formation assay. The antiserum strongly inhibited the first step of nodule formation in B. mori larvae. Next, we tried to knock out BmToll10-3 using genome editing. Strains that were heterozygous for a truncated BmToll10-3 allele were generated, but no strain that was homozygous for truncated BmToll10-3 was generated. Nonetheless, several healthy homozygous larvae were identified before pupation, and we used these larvae in a nodule formation assay. The larvae that were homozygous for truncated BmToll10-3 did not form nodules. These results suggest that BmToll10-3 is involved in a cellular immunity, nodule formation.

A novel indole-2,3-epoxide equivalent, 2-hydroxyindoline-3-triethylammonium bromide, was found to be a convenient reagent for formal C3-electrophilic reactions of indoles with various nucleophiles. By taking advantage of the nucleophilic character of the oxygen of the 2-hydroxyindoline, the interrupted retro-Claisen and interrupted Feist-Bénary reactions with 1,3-dicarbonyl compounds were efficiently achieved.

Fan blades are subjected to very high-cycle loadings during the design life, so it is essential to evaluate the giga-cycle fatigue characteristics of carbon fiber reinforced plastic (CFRP) laminates. In this study, the transverse crack initiation of the cross-ply CFRP laminates in very high-cycle fatigue region was evaluated using an ultrasonic fatigue testing machine. The fatigue tests were conducted at the frequency of f = 20 kHz and the stress ratio of R = −1. In order to suppress temperature rise of the specimen, the intermittent operation with the loading time of 200 ms and the dwelling time of 2000 ms was adopted. The fatigue life data to transverse crack initiation in very high-cycle fatigue region was compared with the data of the fatigue test which was conducted at the frequency of f = 5 Hz and the stress ratios of R = 0.1 and −1 using a hydraulic control fatigue test machine. It was evaluated considering the influences of the stress ratio and the thermal residual stress by using the modified Walker model. The fatigue life to the transverse crack initiation of the cross-ply CFRP laminates in the very high-cycle region exceeding 108 cycles was on the extension of the test data in the low cycle region.

Debris flow simulations are useful for predicting the sediment supplied to watersheds from upstream areas. However, the topographic conditions upstream are more complicated than those downstream and the relationship between the topographic conditions and debris flow initiation is not well understood. This study compared the use of several entrainment rate equations in numerical simulations of debris flows to examine the effect of topographic conditions on the flow. One-dimensional numerical simulations were performed based on the shallow water equations and three entrainment rate equations were tested. These entrainment rate equations were based on the same idea that erosion and the deposition of debris flows occur via the difference between the equilibrium and current conditions of debris flows, while they differed in the expression of the concentration, channel angle, and sediment amount. The comparison was performed using a straight channel with various channel angles and a channel with a periodically undulating surface. The three entrainment rate equations gave different amounts of channel bed degradation and hydrographs for a straight channel with a channel angle greater than 21° when water was supplied from upstream at a steady rate. The difference was caused by the expression of the entrainment rate equations. For channels with little undulation, the numerical simulations gave results almost identical to those for straight channels with the same channel angle. However, for channels with large undulations, the hydrographs differed from those for straight channels with the same channel angle when the channel angle was less than 21°. Rapid erosion occurred and the hydrograph showed a significant peak, especially in cases using the entrainment equation expressed by channel angle. This was caused by the effects of the steep undulating sections, since the effect increased with the magnitude of the undulation, suggesting that a debris flow in an upstream area develops differently according to the topographic conditions. These results also inferred that numerical simulations of debris flow can differ depending on the spatial resolution of the simulation domain, as the resolution determines the reproducibility of the undulations.

Pressure effects on the bilayers of polyoxyethylene type nonionic surfactant in water have been investigated by means of small- and wide-angle X-ray scattering. It has been found that the Krafft transition from the micellar phase to the lamellar gel phase (Lβ) is induced by pressure. By further pressurizing, the lamellar structural parameters, such as the repeat distance d and Caillé parameter η, discontinuously decrease after taking a maximum. All the SAXS and WAXS results revealed that the Lβ phase is transformed into the higher-ordered lamellar crystal phase (Lc). On the basis of these observations, we have made the T-C and T-P phase diagrams.

An experimental study on CH 4 /air propagating flames in a packed pebble bed was performed over a wide range of ambient pressures and flow velocities to clarify the combustion characteristics in a packed bed at high pressure. It focused on the turbulent flame propagation in cases that the flame thickness was sufficiently smaller than the void scale of the packed bed at high pressure. The flame speed was successfully measured at pressures of 0.1–1.0 MPa and flow velocities of 5–130 cm/s using a high-speed video camera, and then the relationships between the flame speed and pressure, flow velocity, pebble diameter and pebble Reynolds number, Re p , were examined. Turbulence measurements at high pressure were also conducted using a 2-D pseudo packed pebble bed to investigate the turbulence intensities in the flow channels and the estimated turbulent flame structure. Results of flame propagation experiments showed that the flame speed in a packed bed had a minimum value at Re p ≅ 150 and rapidly increased with the increase of the flow velocity and pressure. Results obtained in the turbulence measurements indicated that this change of the flame propagation mode was caused by the transition from laminar to turbulent flow when the pressure increased. A significant correlation was seen between the flame speed in a packed bed, S r , at high pressure and the turbulent burning velocity, S T , estimated from the results of turbulence measurements and previous studies on turbulent premixed Bunsen flames by Kobayashi et al., indicating the similarity between the turbulent premixed combustion with and without packed pebbles at high pressure. Flame extinction during propagation at high pressure was also seen as well as at ordinary pressure, the extinction mechanism being explained based on the competition between the heat release in turbulent flames and turbulent heat transfer to the pebbles.

Effects of nucleotides and cations on 2-[125I]iodomelatonin binding sites in the goldfish brain were examined. Nucleotides (10–6–10–3 M) dose-dependently inhibited the specific binding with the following order of potency: guanosine 5''-O-(3-thiotriphosphate) (GTPγS) >GTP = GDP >GMP = ATP >cyclic GMP. Cyclic AMP was ineffective. The treatment of membranes with GTPγS induced rapid dissociation of 2-[125I]iodomelatonin from membranes when added at the steady state, increased the Kd and decreased the Bmax values as revealed by saturation analysis, and increased the IC50 value of melatonin to inhibit the specific binding. The treatment decreased the specific binding to membrane preparations obtained from six brain regions as well. Inorganic salts (5–200 mM) dose-dependently inhibited the specific binding with the following order of potency: CaCl2 > MgCl2 > LiCl > NaCl > choline chloride > KCl, except for 5 mM MgCl2, which enhanced the specific binding. Saturation experiments demonstrated that 75 mM CaCl2,100 mM MgCl2 and 200 mM NaCl increased the Kd and decreased the Bmax while 5 mM MgCl2 increased the Bmax value. These results imply that G protein and physiological concentrations of cations are involved in the regulation of melatonin binding sites in the goldfish brain.

In an attempt to define the role of the pineal hormone melatonin and two analogues (5-methoxytryptamine, 5MT, and 6-hydroxymelatonin, 6HM) in limiting oxidative stress, the present study investigated the changes in glutathione, lipid peroxidation, and the activity of the antioxidant enzyme glutathione peroxidase after exercise (swimming for 60 min) with or without treatment with the indolamines mentioned. Lipid peroxidation was measured by estimating tissue levels of malondialdehyde and 4-hydroxyalkenals; the experimental animals in these studies were male Sprague-Dawley rats. In the liver, swimming exercise increased the levels of reduced glutathione (GSH) and also significantly increasing oxidized glutathione (GSSG), while decreasing the GSH/GSSG ratio, an index directly related to oxidative stress. When the animals were treated with melatonin, the concentrations of GSH and GSSG were also increased after swimming; however, no reduction in the GSH/GSSG ratio appeared. In the animals treated with 6HM the changes were the same as in those treated with melatonin. In muscle as well, the concentration of GSH and the GSH/GSSG ratio were decreased following 60 min of swimming. Pretreatment of the rats with melatonin prevented these effects. Pretreatment of the rats with both 5MT and 6HM also prevented the changes. Brain GSH/GSSG ratio was not affected by either exercise or indolamine administration. Swimming enhanced lipid peroxidation in the liver, muscle and brain; however, this was prevented in animals treated with melatonin or 6HM before swimming. Glutathione peroxidase was significantly elevated after exercise in the brain but not in the liver and muscle. It is concluded that swimming imposes a severe oxidative stress and suggests that melatonin and, to a lesser degree, 5MT and 6HM confer protection against the oxidative damage associated with swimming for 60 min. This mechanism may be reasonably attributed to their indole structure, which possibly allows these molecules to act as free-radical scavengers.

In order to develop a stain with increased sensitivity and selectivity for cadmium (Cd), we synthesized and characterized 2-(8-quinolylazo)-4,5-diphenylimidazole (QAI). This chelating agent was more than twice as sensitive for Cd than the best conventional staining agents, including benzothiazolylazo-beta-naphthol. Differentiation between Cd and zinc (Zn) was achieved by immersing tissue sections in TRIS(2-aminoethyl)amine before they were stained with QAI. This pretreatment made it possible to selectively stain for Cd by blocking Zn.

The present study used male Sprague-Dawley rats to investigate changes in glutathione [reduced (GSH) and oxidized GSH (GSSG)], lipid peroxidation (as indicated by tissue levels of malonaldehyde and 4-hydroxyalkenals), and the activity of the antioxidant enzyme glutathione peroxidase after a bout of swimming (30 min.) with or without melatonin (N-acetyl-5-methoxytryptamine) treatment. In muscle, the concentration of GSH and the GSH/GSSG ratio were decreased following 30 min. of swimming ; these changes are indicative of enhanced oxidative stress. Pretreatment with melatonin prevented these effects. In liver, swimming increased significantly both GSH and GSSG, and decreased the GSH/GSSG ratio. When animals were treated with melatonin, concentrations of GSH and GSSG were also increased after swimming ; however, the reduction in the GSH/GSSG ratio was prevented by melatonin. Brain GSH/GSSG ratio was not affected by exercise or by melatonin. Swimming enhanced the levels of lipid peroxidation products is muscle ; this was prevented in animals treated with melatonin. Glutathione peroxidase activity was significantly elevated after swimming in both liver and brain with the change not being influenced by concurrent melatonin treatment. It is concluded that swimming imposes an oxidative stress on liver and skeletal muscle and the results show that melatonin confers partial protection against oxidative toxicity, especially in muscle.

Melatonin (N-acetyl-5-methoxytryptamine) was identified in the head and hemolymph of the silkworm, Bombyx mori, using reversed-phase high-performance liquid chromatography coupled with fluorometric detection and radioimmunoassay. In addition, evidence of arylakylamine (serotonin) N-acetyltransferase (NAT) a key enzyme controlling the synthesis of melatonin in vertebrates, was found in the head of the silkworm. Melatonin levels in the head and hemolymph and the NAT activity in the head were significantly higher during the dark period than during the light period of a 12-h light/12-h dark cycle. The day-night changes persisted in constant darkness but were suppressed by constant light. The results suggest that the synthesis and release of melatonin in the silkworm head occur as a circadian rhythm that is entrained by environmental light/dark cycles, as it is in the pineal gland of vertebrates. Melatonin in the silkworm head may function as a neurochemical mediator of photoperiodic control of developmental events such as molting, eclosion and diapause.

The effects of scale and fluid properties on gas entrainment onset were experimentally studied for the free surface flow in an IHX vessel of a proposed Japanese demonstration FBR. Water experiments were performed using the 1 10 - th , 1 6 - th , 1 3 - rd and 1 1.6 - th scaled models of the IHX. The experimental results indicate that the scale has a strong effect on gas entrainment onset and that the critical Fr number decreases in proportion to the −0.5-th power of the scale. Applicability of a computational method to the gas entrainment is also discussed by comparing computational and experimental results.

Small-model tests were performed to examine the integrity of the containment flange gasket in a severe accident. During a severe accident, containment structures suffer slow pressurization at relatively high temperatures. A realistic understanding of containment performance in such conditions is a major concern in developing an accident management strategy. This paper describes the results of experiments on the sealing capability of flange gaskets at high pressures and high temperatures. Silicone-rubber gaskets, which are used as the sealing material in BWR plant primary containment vessels (PCV) in Japan, were examined in small-model tests. The gaskets show sufficient sealing capability up to 225°C at 20 kgf/cm 2 . When applying the leakage characteristics specified in this paper to codes for severe accidents, the results should be examined carefully based on realistic heattransfer phenomena.

To understand more about growth-associated protein-43 (GAP-43), we produced transgenic carp by introduction of a rat GAP-43 cDNA linked to the Rous sarcoma virus-long terminal repeat into fertilized eggs. Of 180 eggs microinjected with exogenous gene, 59 embryos hatched and 4 fish were found to contain the exogenous gene sequences in the genomic DNA. From a mature female transgenic carp, parthenogenetically, 126 progeny were derived and 52 of them survived for more than 90 days. The exogenous gene sequences were detected in 22 F1 progeny, and its messenger RNA was detected in all of 10 transgenic F1 carp examined. In serum-free medium, cultured retinal ganglion cells isolated from transgenic carp elongated their axons, while non-transgenic cells did not elongate axons.

Immunocytochemical detection of ubiquitin in the nucleus of rat LH cells and the effects of castration and testosterone replacement on the occurrence of immunoreactive ubiquitin in the nucleus were investigated. Immunoreactive ubiquitin occurred in certain nuclei, mostly belonging to identified LH cells. The concentration of testosterone in blood was altered by castration and implantation of testosterone into castrated rats, and the occurrence of ubiquitin was examined weekly for the following 4 weeks. In castrated rats, the proportion of LH cells with ubiquitin-immunoreactive nuclei was high throughout the experiment. In castrated rats implanted with testosterone, on the contrary, the proportion remained significantly lower. Ubiquitin may be involved in the cellular activity of LH cells in the rat pituitary.

Distribution of fibronectin, laminin, and collagens type I, III, IV, and V in the lobular regions of regenerating rat liver was studied by indirect immunofluorescence. Little or no laminin was detected in sham-operated controls throughout the experimental period, while it was detected in sinusoids of regenerating liver as early as 6 h after partial hepatectomy (PH). After reaching a maximum at 24 h, it decreased and was barely detectable 6 days after PH. Changes in the other extracellular matrix (ECM) proteins were evident 3 days after PH, but not earlier than 24 h. Hepatocytes isolated from regenerating rat livers were tested in a short term assay for attachment to the substrates coated with the ECM proteins. The attachment of hepatocytes to laminin substrates increased 12 h after PH, reached a maximum at 24 h, and decreased to the control level 6 days after PH, while that of the control remained constant. The attachment to fibronectin substrates was not different between regenerating livers and controls at any time point. The attachment to collagen did not change earlier than 24 h after PH, but increased slightly 3 days after PH. Primary rat hepatocytes cultured on the substrates coated with the ECM proteins were determined for replicative DNA synthesis in response to epidermal growth factor. Both in normal liver and in regenerating liver 24 h after PH, laminin was one of the most effective substrates in supporting the responsiveness of hepatocytes to the growth stimulus. Taken together, these results suggest the importance of hepatocyte-laminin interaction during the early stage of liver regeneration possibly in growth stimulation of hepatocytes and/or maintenance of hepatocyte-specific functions.

In this study, 3 GH-producing adenomas were studied as materials to clarify the usefulness of electron microscopic investigation of plaque-forming single adenoma cells, and ultrastructural morphometric comparisons were made to determine whether some differences exist at the cytoplasmic organelle level between small plaque-forming cells and large plaque-forming cells. In two cases, the relative cytoplasmic volume density of Golgi apparatus and lysosomes were significantly greater and the diameter of seretory granules were significantly smaller in large plaque-forming cells compared to small plaque-forming cells. Moreover, in one of them, not only the diameter but also the cytoplasmic volume density of secretory granules were significantly smaller in large plaque-forming cells. These findings suggest a greater secretory granule synthesis and internal granule destruction, and faster granules secretion at an early stage of formation in large plaque-forming cells compared with small plaque-forming cells. It became apparent through this study that electron microscopic investigation of plaque-forming single cells is practically useful since plasma membrane and cytoplasmic organelles were preserved well after processing for EM in most plaque-forming cells.

Ocular melatonin rhythms in the goldfish were studied and compared to those in the pineal organ and plasma. Under light:dark (LD) of 12 h light:12 h dark, melatonin contents in the eye as well as the pineal organ and plasma exhibited clear day-night changes with higher levels at mid-dark than at mid-light. However, melatonin contents in the eye at mid-light and mid-dark were approximately 100 and 9 times greater than those in the pineal organ, respectively. Day-night changes of ocular melatonin persisted after pinealectomy, which abolished those in plasma melatonin under LD 12:12. Ocular melatonin contents in the pinealectomized fish at mid-light were significantly higher than those in the sham-operated control. Under constant darkness (DD), circadian melatonin rhythms were observed in the eye but damped on the 3rd day, whereas plasma melatonin rhythms generated by the pineal organ persisted for at least 3 days. Under constant light, ocular melatonin contents exhibited a significant fluctuation with a smaller amplitude than that under DD, whereas plasma melatonin remained at low levels. These results indicate the involvement of LD cycles, a circadian clock, and the pineal organ in the regulation of ocular melatonin rhythms in the goldfish.

Melatonin binding sites in the goldfish brain were characterized by radioreceptor assay using 2-[125I]iodomelatonin as the radioligand. Specific binding of 2-[125I]iodomelatonin was rapid, stable, saturable and reversible. Saturation experiments demonstrated that 2-[125I]iodomelatonin binds to a single class of receptor site with an affinity constant (Kd) of 29.8 +/- 0.7 pM and a total binding capacity (Bmax) of 11.47 +/- 0.33 fmol/mg protein at mid-light. At mid-dark, the Bmax value decreased significantly to 7.90 +/- 0.23 fmol/mg protein (P0.01) with no significant variation in the Kd value (33.8 +/- 1.5 pM). Competition experiments revealed the following order of pharmacological affinities: 2-iodomelatoninmelatonin6-hydroxymelatoninN-acetyl-5-hydroxytryptamine5-methoxytryptamine5-methoxytryptophol5-methoxyindole-3-acetic acid. 5-Hydroxytryptamine, 5-hydroxytryptophol, 5-hydroxyindole-3-acetic acid, norepinephrine and acetylcholine exhibited no inhibition. Subcellular distribution of melatonin binding sites was demonstrated to be greatest in the P2 and P3 fractions as compared with the P1 fraction. Localization of melatonin binding sites in discrete brain areas was determined to be highest in the optic tectum-thalamus and hypothalamus, intermediate in the telencephalon, cerebellum and medulla oblongata, and lowest in the olfactory bulbs and pituitary gland. These results suggest that characteristics of melatonin receptors are highly conserved during evolution and that in this species melatonin plays neuromodulatory roles in the central nervous system through specific receptors.

We studied growth hormone (GH) and prolactin (PRL) messenger ribonucleic acids (mRNAs) in 14 cases with densely granulated somatotroph (DG) adenomas and 10 cases with sparsely granulated somatotroph (SG) adenomas using in situ hybridization with digoxigenin-labeled probes and correlated these data with their immunohistochemical results. A good correlation between in situ hybridization results and immunohistochemical data was found in most cases examined. The DG adenomas generally had a diffuse and intense GH immunoreactivity and GH hybridization signal, whereas in SG adenomas the number of cells exhibiting a GH mRNA signal and the strength of the GH mRNA signal in these cells were relatively lower than those of DG adenomas, indicating that lower expression of the GH mRNA signal is responsible for lower GH production in SG adenomas. In addition, PRL mRNA expression differed in the two types of adenoma; in DG adenomas, seven cases (50%) expressed PRL mRNA signal with a focal or scattered distribution despite normal serum PRL levels, but two showed no PRL immunoreactivity. In contrast, in SG adenomas, only one case contained a few cells possessing a PRL mRNA signal despite having no PRL immunoreactivity. It can be concluded that DG and SG adenomas, which have been considered variants of the same tumor, display definite differences as to GH or PRL gene expression in each type of adenoma.

Generation and reception of melatonin signals in the goldfish, Carassius auratus, are reviewed. The photoreceptive pineal gland of the goldfish generates circulating melatonin rhythms according to a given photoperiod under light-dark cycles and in a circadian manner under continuous dark conditions. Melatonin is also produced in the retina in a similar fashion. Melatonin produced in the pineal gland and retina is considered to act as internal zeitgeber in the brain and retina, respectively, controlling various physiological events via specific melatonin binding sites that are coupled with G protein. The goldfish exhibit clear diurnal locomotor activity rhythms under light-dark cycles and free-running rhythms under constant conditions. However, the relationship between melatonin and locomotor activity rhythms in the goldfish remains unclear. Further studies should be required to demonstrate the roles of melatonin in the circadian system in this species.

A quantitative analysis of the pituitary gland was conducted to ascertain the effects of protein-calorie malnutrition on the morphology of the somatotrophs, gonadotrophs, thyrotrophs, and corticotrophs. Male rats were fed a low, 8% protein diet from 20 to 50 days of age, while their age-matched controls were given a diet containing 27% protein. The hypophyses were then processed for light microscopic immunocytochemical staining using antibodies to growth hormone, the β subunits of luteinizing hormone and thyroid stimulating hormone, and adrenal corticotrophic hormone. The number of each cell type along with an evaluation of the cell, cytoplasmic, and nuclear areas was conducted using a computerized image analyzer. All of these parameters were reduced significantly in the somatotrophs as a result of the low protein diet, while in the gonadotrophs, the cell, cytoplasmic, and nuclear areas were similarly affected. Smaller cell number, cell area, and nuclear area were noted in the corticotrophs of the malnourished animals, while in the thyrotrophs, only the cell and nuclear areas were reduced. The data demonstrate that each pituitary cell type responds in a unique manner to undernutrition. © 1993 Wiley-Liss, Inc.