Thermoelectric signature of quantum critical phase in a doped spin-liquid candidate

Quantum spin liquid is a nontrivial magnetic state of longstanding interest, in which spins are strongly correlated and entangled but do not order; further intriguing is its doped version, which possibly hosts strange metal and unconventional superconductivity. A promising candidate of the doped spin liquid is a triangular-lattice organic conductor, κ-(BEDT-TTF)₄Hg_2.89Br₈, recently found to hold metallicity, spin-liquid-like magnetism, and BEC-like superconductivity. The nature of the metallic state with the spin-liquid behaviour is awaiting to be further clarified. Here, we report the thermoelectric signature that mobile holes in the spin liquid background are in a quantum critical state and it pertains to the BEC-like superconductivity. The Seebeck coefficient divided by temperature, S/T, is enhanced on cooling with logarithmic divergence indicative of quantum criticality. Furthermore, the logarithmic enhancement is correlated with the superconducting transition temperature under pressure variation, and the temperature and magnetic field profile of S/T upon the superconducting transition change with pressure in a consistent way with the previously suggested BEC-BCS crossover. The present results reveal that the quantum criticality in a doped spin liquid emerges in a phase, not at a point, and is involved in the unconventional BEC-like nature.

Ultrasonic measurement of dentin remineralization effects of dentifrices and silver diamine fluoride

OBJECTIVE

This study investigated the dentin remineralization effect of the application of a functionalized tri-calcium phosphate (fTCP) dentifrice and a silver diamine fluoride (SDF) solution.

MATERIAL AND METHODS

The materials used were: a fluoride-containing dentifrice with fTCP (fTCP＋), a fluoride-containing dentifrice without fTCP (fTCP-) and a 38% SDF solution. Following treatment, the dentin slabs were immersed in a 0.1-M lactic acid buffer solution and then placed in artificial saliva. This procedure was repeated three times daily for 28 days. The propagation time of longitudinal ultrasonic velocities (UV) and the Knoop hardness (KH) of the samples were measured. The samples were also observed using scanning electron microscopy.

RESULTS

The SDF and fTCP＋ groups showed higher UV than the fTCP - group regardless of the application method. The F-SDF group at 28 days showed significantly higher UV (4121 ± 102 m/s) than the F-fTCP + group (3731 ± 65 m/s) (p < .05). The F-SDF group at 28 days showed significantly higher KH (47.4 ± 2.2) than the F-fTCP＋ group (43.3 ± 1.0) and the F-fTCP - group (42.9 ± 2.1) (p < .05). Closure of the dentinal tubules and crystal precipitation was detected on the surface of the fTCP＋ group to a greater extent than the fTCP - group.

CONCLUSIONS

The fTCP-containing dentifrice and SDF solution effectively enhanced bovine dentin remineralization.

Bonding ability of resin cements to different types of CAD/CAM composite blocks

This study investigated the bonding performance of two different types of resin cements to computer-aided design/computer-aided manufacturing (CAD/CAM) composite blocks based on the shear bond strength (SBS) test. A silane-containing self-adhesive resin cement (Panavia SA Cement Universal) and resin luting cement (Block HC Cem) with a primer, were used. Specimens were fabricated from three different types of CAD/CAM composite blocks, and their surfaces were blasted with alumina. Resin cements were bonded to the specimens, and their SBSs were measured after 15 min, 24 h, and after being subjected to thermal cycling for 10,000 and 30,000 cycles. Three-way ANOVA for bond strength revealed that CAD/CAM composite block, resin cement and storage time significantly influenced the SBS values, and the three-way interactions between the evaluated factors, and all the interactions were significant. It was concluded that the bonding performance of resin cements to CAD/CAM composite blocks were material and storage period dependent.

Prevention of acidic attack on tooth enamel surfaces using polishing paste containing ion-releasing filler

The purpose of this study was to investigate the ability of polishing paste containing surface pre-reacted glass-ionomer (S-PRG) filler to prevent acidic attack on tooth enamel surfaces. Resin composites were filled in the standardized cavities and finished with silicon carbide paper. These specimens were divided into three groups: the unpolished "control" group, the "PRG" group polished with S-PRG paste, and the "DDP" group polished with diamond-containing polishing paste. Following polishing, the specimens were immersed in a lactic acid buffer solution for 28 days. Optical coherence tomography (OCT) signals were measured to obtain the signal intensity and width at 1/e² at selected locations on the enamel surface adjacent to the restoration. Although signal intensity significantly increased in all groups, widths at 1/e² did not change significantly in the PRG group. For both the control and DDP groups, signal intensity and width at 1/e² increased and decreased over time, respectively.

Measurement of Coherent π^{+} Production in Low Energy Neutrino-Carbon Scattering

We report the first measurement of the flux-averaged cross section for charged current coherent π^{+} production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al.

Identification of Shell Colour Pigments in Marine Snails Clanculus pharaonius and C. margaritarius (Trochoidea; Gastropoda)

Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplars of biological pigmentation, with the vivid colours of sea shells particularly prized by collectors and scientists alike. Biochemical studies of molluscan shell colour were fairly common in the last century, but few of these studies have been confirmed using modern methods and very few shell pigments have been fully characterised. Here, we use modern chemical and multi-modal spectroscopic techniques to identify two porphyrin pigments and eumelanin in the shell of marine snails Clanculus pharaonius and C margaritarius. The same porphyrins were also identified in coloured foot tissue of both species. We use high performance liquid chromatography (HPLC) to show definitively that these porphyrins are uroporphyrin I and uroporphyrin III. Evidence from confocal microscopy analyses shows that the distribution of porphyrin pigments corresponds to the striking pink-red of C. pharaonius shells, as well as pink-red dots and lines on the early whorls of C. margaritarius and yellow-brown colour of later whorls. Additional HPLC results suggest that eumelanin is likely responsible for black spots. We refer to the two differently coloured porphyrin pigments as trochopuniceus (pink-red) and trochoxouthos (yellow-brown) in order to distinguish between them. Trochopuniceus and trochoxouthos were not found in the shell of a third species of the same superfamily, Calliostoma zizyphinum, despite its superficially similar colouration, suggesting that this species has different shell pigments. These findings have important implications for the study of colour and pattern in molluscs specifically, but in other taxa more generally, since this study shows that homology of visible colour cannot be assumed without identification of pigments.

Measurement of Muon Antineutrino Oscillations with an Accelerator-Produced Off-Axis Beam

T2K reports its first measurements of the parameters governing the disappearance of ν[over ¯]_{μ} in an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic ν[over ¯]_{μ} beam, produced with a peak energy of 0.6 GeV at J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the ν[over ¯]_{μ} survival probability is expected to be minimal. Using a data set corresponding to 4.01×10^{20} protons on target, 34 fully contained μ-like events were observed. The best-fit oscillation parameters are sin^{2}(θ[over ¯]_{23})=0.45 and |Δm[over ¯]_{32}^{2}|=2.51×10^{-3}  eV^{2} with 68% confidence intervals of 0.38-0.64 and 2.26-2.80×10^{-3}  eV^{2}, respectively. These results are in agreement with existing antineutrino parameter measurements and also with the ν_{μ} disappearance parameters measured by T2K.

Heterospecific female mimicry in Ficedula flycatchers

Mimicry is a widespread phenomenon. Vertebrate visual mimicry often operates in an intraspecific sexual context, with some males resembling conspecific females. Pied flycatcher (Ficedula hypoleuca) dorsal plumage varies from the ancestral black to female-like brown. Experimental studies have shown that conspecific and heterospecific (collared flycatcher, F. albicollis) individuals of both sexes respond, at least initially, to brown individuals as if they were female. We quantified the perceptual and biochemical differences between brown feathers and found that brown pied flycatcher males are indistinguishable from heterospecific, but not from conspecific, females in both aspects. To our knowledge, this is the first evidence of a visual mimetic signalling system in a sexual context where the model is heterospecific to the mimic. By only mimicking heterospecific females, brown pied flycatcher males can establish territories next to the more dominant collared flycatcher in sympatry, suffer less aggression by darker conspecifics in allopatry and preserve within-species sexual recognition throughout the breeding range. A closer look at the evolutionary history and ecology of these two species illustrates how such a mimetic system can evolve. Although likely rare, this phenomenon might not be unique to Ficedula flycatchers.

Diversity of human hair pigmentation as studied by chemical analysis of eumelanin and pheomelanin

Hair colour is one of the most conspicuous phenotypes in humans, ranging from black, brown, blond to red. This diversity arises mostly from the quantity and ratio of the black-dark brown eumelanin and the reddish-brown pheomelanin. To study the chemical basis underlying the diversity of hair colour, we have developed several chemical methods to quantify those two pigments. Alkaline H(2) O(2) oxidation affords pyrrole-2,3,5-tricarboxylic acid (PTCA) as a eumelanin marker and thiazole-2,4,5-tricarboxylic acid (TTCA) as a pheomelanin marker. Pheomelanin can also be analysed as 4-amino-3-hydroxyphenylalanine (4-AHP) after hydroiodic acid hydrolysis. Using those methods, we evaluated the contents of eumelanin and pheomelanin (the 'chemical' phenotype) in human hairs of black, dark brown, brown, light brown, blond and red colour (the 'visual' phenotype). Eumelanin contents decrease in that order, with a trace but constant level of pheomelanin, except for red hair which contains about equal levels of pheomelanin and eumelanin. Thus, the chemical phenotype correlates well with the visual phenotype. The genotype of melanocortin-1 receptor (MC1R), a gene regulating the red hair phenotype, is predictive of hair melanin expressed as the log value of eumelanin to pheomelanin ratio, with a dosage effect evident. Hair melanin contents were also analysed in patients with various hypopigmentary disorders including Hermansky-Pudlak syndrome, Menkes disease, proopiomelanocortin deficiency, cystinosis, malnutrition and trace metal deficiency. The chemical phenotype helped evaluate the precise effects of each disease on pigmentation. In studies of human hair, the chemical phenotype will find more and more application as an objective measure of pigmentation.

Lymphangiogenesis associated with acute cellular rejection in rat liver transplantation

Lymphangiogenesis may be important for the cellular immune response in liver transplantation. In the present study, we examined lymphangiogenesis in liver allografts displaying acute cellular rejection (ACR), or long-term acceptance, or severe ACR plus antibody-mediated rejection (AMR). ACR and subsequent long-term graft acceptance developed in liver transplantations from DA to PVG rats without immunosuppression (mean survival time more than 90 days). Severe ACR and AMR developed in liver transplantations from DA to Lewis rats without immunosuppression (mean survival = 11 days). Normal DA donor livers before transplantation showed a small number of lymphatic vessels around portal veins. DA liver grafts in PVG showed ACR with lymphangiogenesis in portal areas and portal-portal bridging areas with cellular infiltration. Newly formed lymphatic vessels in ACR were characterized by proliferating endothelial cells with expression of the homeobox transcription factor PROX-1 and surrounded by discontinuous basement membranes. Thereafter, the infiltrates spontaneously disappeared, and the grafts survived more than 90 days. During the resolution of the cellular infiltration, expanded lymphatic vessels were packed with many lymphocytes. Thereafter, the number of lymphatic vessels decreased. In contrast, severe ACR and AMR in DA-to-Lewis transplantations showed lymphatic vessels disappeared with edema in the portal areas at day 11. In conclusion, lymphangiogenesis occurred during ACR. It may be involved in the resolution of ACR and reduction of inflammation. In severe ACR and AMR, lymphatic vessels were destroyed, which may be involved in persistent severe inflammation.

TRP-2 expression protects HEK cells from dopamine- and hydroquinone-induced toxicity

We previously reported that melanogenic enzyme TRP-2 (or DCT for DOPAchrome tautomerase) expression in WM35 melanoma cells resulted in increased intracellular GSH levels, reduction in DNA damage induced by free radicals, and decreased cell sensitivity to oxidative stress. These effects seemed to depend on a particular cellular context, because none of them were found to occur in HEK epithelial cells. We postulated that the TRP-2 beneficial effect observed in WM35 cells in the oxidative stress situation may relate to quinone metabolization and, more precisely, to the ability of TRP-2 to clear off related toxic metabolites, resulting in a global redox status modification. Here, a comparative protein expression profiling of catecholamine biosynthesis enzymes and detoxification enzymes was conducted in WM35 melanoma cells and in HEK epithelial cells, in comparison with normal human melanocytes. Results showed that WM35 cells, but not HEK cells, expressed enzymes involved in catecholamine biosynthesis, suggesting that their quinone-related toxic metabolites were present in WM35 cells but not in HEK cells. To address the issue of a possible TRP-2 beneficial effect toward quinone toxicity, cell survival experiments were then conducted in HEK cells using dopamine and hydroquinone at toxic concentrations. We showed that TRP-2 expression significantly reduced HEK cell sensitivity to both compounds. This beneficial property of TRP-2 was likely to depend on the integrity of its DOPAchrome tautomerase catalytic site, because both TRP-2(R194Q) and TRP-2(H189G), which have lost their DOPAchrome tautomerase activity, failed to modify the HEK cell response to dopamine and hydroquinone. These results suggest that TRP-2 acts on quinone metabolites other than DOPAchrome, e.g., in the catecholamine pathway, and limits their deleterious effects.

The melanogenic system of the liver pigmented macrophages of Rana esculenta L.--tyrosinase activity

The enzyme system responsible for Amphibian Kupffer Cell (KC) melanogenesis has not been entirely elucidated. This research demonstrates that the KC melanosomes of Rana esculenta L. possess a tyrosine-hydroxylase (TH) activity, showing that a tyrosinase is the enzyme involved in the melanogenesis. The TH reaction depends on catalytic Dopa as a cofactor and is not affected by catalase or H2O2, showing that it is catalysed by the tyrosinase and not by the peroxidase present in the melanosomes. The TH reaction is activated by Cu2+ ions but not by other tyrosinase activators such as limited proteolysis, protein ageing, and Sodium Dodecyl Sulphate (SDS). SDS inhibited the KC TH activity even below the critical micelle concentration. All these results suggest that the KC-tyrosinase differs in structure from other known tyrosinases. Using anti-KC-tyrosinase antobodies, we observed that the sites of the tyrosinase location within the cell are the same as those described in the melanocytes. In the immunoblots, the anti-KC-tyrosinase antibodies also recognised two protein bands, at the higher molecular weight ranges, in the protein electrophoretic pattern. Moreover, the tyrosinase activity was limited to the highest molecular weight band of about 260 kDa, suggesting that the enzyme activity could depend on a molecular aggregate. The melanin produced in the liver was found to be a 5,6-dihydroxyindole-rich eumelanin similar to the Sepia melanin.

Intrathecal administration of ATP produces long-lasting allodynia in rats: differential mechanisms in the phase of the induction and maintenance

Several lines of evidence suggest that extracellular ATP plays a role in pain signaling through the activation of ionotropic P2X-receptors, especially homomeric P2X3- and heteromeric P2X2/3-receptors on capsaicin-sensitive and -insensitive primary afferent neurons, respectively, at peripheral and spinal sites. We investigated the mechanisms of the induction and maintenance of mechanical allodynia produced by a single intrathecal (i.t.) administration of ATP in rats. We found that i.t. administration of ATP and the P2X-receptor agonist alpha,beta-methylene-ATP produced tactile allodynia which lasted more than 1 week. The i.t. ATP- and alpha,beta-methylene-ATP-produced long-lasting allodynia remained in neonatal capsaicin-treated adult rats. I.t. administration of a P2X3/P2X2/3-receptor selective antagonist completely prevented the induction (co-administration on day 0) and partially attenuated the early phase (day 1 post-ATP administration), but not the late phase (day 7 post-ATP administration) of maintenance of allodynia. The N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 completely prevented the induction phase, but not the early and late phases of maintenance of allodynia. Immunohistochemical and immunoblotting studies for microglial and astrocytic markers revealed that i.t. ATP administration caused spinal microglial activation within 1 day, and astrocytic activation which peaked at 1-3 days after ATP administration. Furthermore, minocycline, a microglial inhibitor, attenuated the induction but not the early and late phases of maintenance, while fluorocitrate, a glial metabolic inhibitor, attenuated the induction and the early phase but not the late phase of maintenance. Taken together, these results suggest that the activation of P2X-receptors, most likely spinal P2X2/3-receptors on capsaicin-insensitive primary afferent neurons, triggers the induction of long-lasting allodynia through NMDA receptors, and the induction and early maintenance phase, but not the late phase, is mediated through the functions of spinal glial cells.

Reduplicated basal lamina of the peritubular capillaries in renal biopsy specimens

Reduplicated basal lamina of the peritubular capillaries (PTC) is usually found in kidney allografts in association with chronic transplant nephropathy and sometimes in native renal biopsies. In order to assess the incidence of this phenomenon in native renal biopsy specimens, we have carried out a retrospective review of the diagnostic ultrastructural pathology records of 80 consecutive renal biopsies excluding renal allografts and children with clinical signs of heavy proteinuria. Reduplicated basal lamina of the PTC was found in 19 out of the 80 cases (23.8%) with renal diseases. It was frequently seen in lupus nephritis, IgA nephropathy, and membranoproliferative glomerulonephropathy, being the subtypes of mesangial proliferative lesions. In a few cases it was also found in anti-neutrophil cytoplasmic autoantibody (ANCA) associated glomerulonephritis and benign nephrosclerosis renal biopsies. Reduplicated basal lamina of the PTC was strongly associated with glomerular and peritubular inflammation, and tubular necrosis. Peritubular interstitial edema, slight to moderately increased collagen fibrils, many spiraled collagen fibrils (indicative of degeneration), and collagen fibrils drawing from basal lamina were found around the reduplicated basal lamina of the PTC but not in normal basal lamina. These results indicate that in native renal biopsy specimens, reduplication of the basal lamina of the PTC is associated with endothelial cell injury and capillary permeability abnormality.

A new antigen retrieval method using citraconic anhydride for immunoelectron microscopy: localization of surfactant pro-protein C (proSP-C) in the type II alveolar epithelial cells

In the attempt to develop a pre-embedding immunoelectron microscopic method with improved ultrastructral morphology, we examined an antigen retrieval (AR) method using citraconic anhydride, and compared the effects of glutaraldehyde fixation with routine paraformaldehyde fixation in the pre-embedding immunoelectron microscopic method with reference to the localization of surfactant-associated pro-protein C (proSP-C) in the lung. The glutaraldehyde-fixed tissues were immunostained after AR in 0.05% citraconic anhydride solution, pH 7.4, at 98 degrees C for 60 min. In routine pre-embedding immunoelectron microscopic method using paraformaldehyde fixation, proSP-C positive products were distributed sporadically in the type II alveolar epithelial cells. In glutaraldehyde-fixed tissues without the AR method, proSP-C products were not detected, however after AR in citraconic anhydride proSP-C positive products were distributed specifically, in rough endoplasmic reticulum membranes, Golgi complex membranes, multivesicular bodies and osmiophilic lamellar bodies. The positive proSP-C products also showed lattice-like structures in the alveoli. Thus, the present AR method provides successful pre-embedding immunoelectron microscopy of glutaraldehyde-fixed tissues.

Rate constants for the first two chemical steps of eumelanogenesis

The kinetics of the initial cyclization and redox exchange reactions involved in the eumelanogenic pathway have been studied previously but because of the difficulty of detecting the intermediate cyclodopa by optical means (because its absorbance is in the same range as dopa which is present in excess in the experimental system) no accurate value for the redox exchange reaction has so far been obtained and there is no available analytical methodology that can be applied to the successive first- and second-order reactions involved. We have synthesized cyclodopa and examined the kinetics of the formation of dopachrome following the pulse radiolytic generation of dopaquinone in its presence. From this direct measurement we determined that the rate constant of the reaction between cyclodopa and dopaquinone is 5.3 x 10(6)/M/s. Employing this value in a computational model of the combined cyclization and redox exchange reactions we calculate that the observed kinetics of dopaquinone decay and dopachrome formation are compatible with a cyclization rate constant of 3.8/s.

Eumelanin and phaeomelanin contents of depigmented and repigmented skin in vitiligo patients

BACKGROUND

There are two chemically distinct types of melanin: the red-yellow phaeomelanin and the brown-black eumelanin. Both types of melanin have been detected in human hair, epidermis and cultured melanocytes.

OBJECTIVES

In a preliminary study, to quantify levels of both eumelanin and phaeomelanin in depigmented as well as repigmented patches of vitiligo following psoralen plus ultraviolet A (PUVA) therapy.

METHODS

We enrolled five patients with vitiligo for this study. We took biopsies from depigmented as well as repigmented lesions after PUVA therapy. The eumelanin and phaeomelanin contents of the skin biopsies were quantified by high-performance liquid chromatography.

RESULTS

The mean concentrations in depigmented lesions were 229.4 ng per piece for phaeomelanin and 572 ng per piece for eumelanin (mean phaeomelanin/eumelanin ratio 0.36). In repigmented lesions, the mean concentration of phaeomelanin was 74.8 ng per piece and that of eumelanin was 1657.6 ng per piece (mean phaeomelanin/eumelanin ratio 0.049).

CONCLUSIONS

Depigmented lesions showed both types of melanin, and contained a substantial amount of phaeomelanin, whereas repigmented lesions after PUVA showed predominantly eumelanin. We detected melanin in depigmented lesions of vitiligo of 5 years duration, suggesting that some residual melanocytes are still active in depigmented lesions.

Melanoma inhibitory activity (MIA) as a serum marker for early detection of post-surgical relapse in melanoma patients: comparison with 5-S-cysteinyldopa

One of the principal applications of tumour markers is the early detection of recurrent disease in the follow-up of patients. In the study described here, we compared the usefulness of two serum markers for melanoma, 5-S-cysteinyldopa (5-S-CD) and melanoma inhibitory activity (MIA), in the monitoring of postsurgical melanoma patients. A total of 154 serum samples taken from 45 melanoma patients, who underwent surgery of the primary tumour and were under periodical follow-up for 13 to 180 months, were analysed. Serum MIA measurements were performed using an enzyme-linked immunosorbent assay (ELISA), and 5-S-CD levels were determined using high performance liquid chromatography (HPLC). In 72 serum samples taken from a group of 31 non-progressive patients with a median follow-up of 48.5 months, false positive rates of both markers were equally low, being 6.9% (five out of 72) for 5-S-CD and 8.3% (six out of 72) for MIA. In contrast, the sensitivity of MIA at the time point of the first clinical relapse in 14 progressive patients was significantly greater than that of 5-S-CD (0.64 [nine out of 14] versus 0.21 [three out of 14]; P < 0.05). Furthermore, seven patients showed abnormal serum MIA values 4-53 months prior to the clinical detection of metastasis, and the elevated levels were often noted on multiple occasions. These results show that MIA was superior to 5-S-CD in monitoring melanoma patients under periodical follow-up after the primary surgery. Repeated elevation of serum MIA levels may predict the presence of clinically undetectable occult metastases, which warrants further prospective investigations to assess the prognostic significance of serum MIA levels in postsurgical melanoma patients.

Evaluation of 5-S-cysteinyldopa as a marker of melanoma progression: 10 years' experience

5-S-Cysteinyldopa (5-S-CD) has been used as a biochemical marker of melanoma progression. In this study, we measured serum levels of 5-S-CD in 2648 samples taken from 218 patients in order to evaluate the usefulness of this parameter in following melanoma progression and prognosis. 5-S-CD levels were significantly elevated above the upper limit of the normal range (10 nmol/l) in stage IV melanoma patients. The sensitivity of elevated serum 5-S-CD levels in detecting distant metastasis was 73%, while the specificity was 98% and the positive predictive value 94%. The sensitivity was improved to 77% when cases of amelanotic melanoma were excluded. Patients without metastases had elevated 5-S-CD values in 5% of the 1480 serum samples. Changes in serum 5-S-CD levels were followed during disease progression until the end stage in 49 patients. In 33% of the patients, elevation of serum 5-S-CD levels preceded clinical detection of visceral metastases, and in 37% elevation of 5-S-CD levels occurred at the same time as visceral metastasis. Patients with elevated 5-S-CD levels before or after surgical treatment had significantly shorter survival times than those with normal levels. These results show that the level of 5-S-CD in the serum is a sensitive and specific marker in predicting distant metastases. Elevated serum levels of 5-S-CD, before or after surgical treatment, is associated with a poor prognosis.

Abnormal elastic system fibers in fibrotic human liver

The network of elastic system fibers in human fibrotic liver was investigated by histological methods, immunohistochemical staining, and electron microscopy. Type III collagen was seen not only in regions of portal fibrosis but also in the sinusoidal wall. However, elastic system fibers were not found in the Disse space of the sinusoidal wall. Elastic system fibers including oxytalan, elaunin, and elastic fibers were found successively in the course of elastogenesis. A few normal oxytalan fibers and abnormal oxytalan fibers were observed in the periportal tracts. Few normal elaunin and abnormal elaunin fibers were observed in regions of portal fibrosis but not in the surrounding margin. Elastic fibers, only in scarce amounts, were observed around the portal veins in the case of chronic active hepatitis but not in acute hepatitis. Abnormal oxytalan fibers were seen as a bundle of wavelike microfibrils and had an irregular arrangement. Abnormal elaunin fibers were not associated with bundles of microfibrils. Abnormal elaunin fibers in large amounts were found interspersed with spiraled collagen, which most likely indicates that the oxytalan fibers degenerated in the course of elastogenesis. Thus, in a fibrotic liver it is possible that synthesis of normal elaunin and elastic fibers does not occur or that the quantity of such fibers synthesized may be small because of the effect of the degenerated oxytalan fibers. As a characteristic of liver fibrosis, the composition of abnormal elastic system fibers and spiraled collagen differs from that in other fibrotic organs.

Heart rate variability in normotensive healthy children with aging

Although the heart rate variability (HRV) values in adults decrease with aging, those in children show a variety of changes. The present study was designed to investigate the relationship between HRV and aging, physique and blood pressure in 70 healthy male school children, between 6 and 12 years of age. The subjects were divided into 3 age groups (6-7, 8-9 and 10-12 years) and 3 other groups according to physique (thin, under -10%; normal, -10-20% and obese, over 20% of obesity index). After recording a 24-h ambulatory electrocardiograph, HRV was determined spectrally, using 3 components: the total-frequency (TF) component (0.01 to 0.5 Hz), the low-frequency (LF) component (0.04 to 0.15 Hz), the high-frequency (HF) component (0.15 to 0.5 Hz) and also a two component ratio (LF/HF). The HRV values between the 3 age groups had a significant effect on TF, LF and LF/HF during the 24-h period, with the values increasing with age. The HRV values between the 3 physique groups had no significant effect. Therefore, changes in HRV in school children are affected by age and not physique. It is possible that the increase in HRV values with age is caused by the development of the autonomic nervous system.

Monotypic angiomyolipoma of the nasal cavity: a heretofore undescribed occurrence

A monotypic angiomyolipoma of the nasal cavity in a 34-year-old woman is described. Tumor cells were spindled or epithelioid and contained glycogen and diastase-resistant PAS-positive granules. There were few mitoses, and necrosis was absent, indicating a benign tumor. The stroma was markedly vascular, and a few adipocytes were seen in one area. Cells were positive for melanocyte and muscle markers. Electron microscopy revealed abundant dense granules. Although melanin was absent histochemically, it was present using a chemical assay, and the granules may, therefore, be atypical melanosomes. Fine actin filaments, attachment plaques and lamina were present. Initial assessment of the lesion indicated malignant melanoma, but the immunostaining and histologic features indicated monotypic angiomyolipoma. To the best of our knowledge, this is the first such case in the nasal cavity.

5-S-cysteinyldopa as diagnostic tumor marker for uveal malignant melanoma

PURPOSE

To evaluate the clinical significance of 5-S-cysteinyldopa (5-S-CD), a major intermediate in melanin synthesis, as a potential diagnostic tumor marker for uveal malignant melanoma.

METHODS

The levels of 5-S-CD in the serum were measured by high-performance liquid chromatography in 16 patients with primary uveal melanoma. The levels of 5-S-CD were also measured in both aqueous and vitreous humor in 10 patients with uveal melanoma. The serum of healthy volunteers and patients with skin diseases other than melanoma, and the intraocular fluids of patients with cataract and vitreoretinal diseases were used as controls.

RESULTS

Serum concentrations of 5-S-CD in patients with uveal melanoma in the absence of extraocular metastases were close to those of controls; however, serum concentrations of 5-S-CD were significantly elevated in patients with extraocular metastases of melanoma. Concentrations of 5-S-CD in the intraocular fluids, especially vitreous humor, were higher in patients with uveal melanoma than in controls.

CONCLUSIONS

5-S-CD in intraocular fluids may serve as a useful biochemical marker for the diagnosis of uveal melanoma. Serum 5-S-CD may contribute to the assessment of the presence and progression of extraocular metastases in patients with uveal melanoma.

Effect of increased intracellular melanin concentration on survival of human melanoma cells exposed to different wavelengths of UV radiation

PURPOSE

To investigate the effect of intracellular melanin content on cell survival of G361 human melanoma cells following exposure to UV radiation.

MATERIALS AND METHODS

Cells were cultured in medium containing elevated concentrations of L tyrosine phosphate and L glutamine to increase their melanin content. Cell survival was assessed by colony-forming ability in treated and untreated cells following exposure to 254 nm germicidal UVC radiation (0-60 J m(-2)), 311 nm UVB radiation (0-5 kJ m(-2)), or broadband UVA radiation (Sellamed 4000, maximum output between 350 and 450 nm) (0-1.2 MJ m(-2)).

RESULTS

Treated cells, with a 2-fold increase in total melanin concentration and an increased ratio of eumelanin to pheomelanin, were marginally more resistant than untreated control cells to cell killing by 311 nm UVB radiation, but treatment had no effect on killing by germicidal UVC or broadband UVA radiation.

CONCLUSIONS

There was no evidence of any photosensitizing effect of increased melanin on human melanoma cell survival following exposure to UVC, UVB or broadband UVA radiation. The slight protective effect seen following exposure to UVB radiation may have been due to increased scavenging of reactive-oxygen species, particularly by eumelanin, at this wavelength.

Melanosomal pH controls rate of melanogenesis, eumelanin/phaeomelanin ratio and melanosome maturation in melanocytes and melanoma cells

The skin pigment melanin is produced in melanocytes in highly specialized organelles known as melanosomes. Melanosomes are related to the organelles of the endosomal/lysosomal pathway and can have a low internal pH. In the present study we have shown that melanin synthesis in human pigment cell lysates is maximal at pH 6.8. We therefore investigated the role of intramelanosomal pH as a possible control mechanism for melanogenesis. To do this we examined the effect of neutralizing melanosomal pH on tyrosinase activity and melanogenesis in 11 human melanocyte cultures and in 3 melanoma lines. All melanocyte cultures (9 of 9) from Caucasian skin as well as two melanoma cell lines with comparable melanogenic activity showed rapid (within 24 h) increases in melanogenesis in response to neutralization of melanosomal pH. Chemical analysis of total melanin indicated a preferential increase in eumelanin production. Electron microscopy revealed an accumulation of melanin and increased maturation of melanosomes in response to pH neutralization. In summary, our findings show that: (i) near neutral melanosomal pH is optimal for human tyrosinase activity and melanogenesis; (ii) melanin production in Caucasian melanocytes is suppressed by low melanosomal pH; (iii) the ratio of eumelanin/phaeomelanin production and maturation rate of melanosomes can be regulated by melanosomal pH. We conclude that melanosomal pH is an essential factor which regulates multiple stages of melanin production. Furthermore, since we have recently identified that pink locus product (P protein) mediates neutralization of melanosomal pH, we propose that P protein is a key control point for skin pigmentation. We would further propose that the wide variations in both constitutive and facultative skin pigmentation seen in the human population could be associated with the high degree of P-locus polymorphism.

Molecular and phenotypic analysis of Attractin mutant mice

Mutations of the mouse Attractin (Atrn; formerly mahogany) gene were originally recognized because they suppress Agouti pigment type switching. More recently, effects independent of Agouti have been recognized: mice homozygous for the Atrn(mg-3J) allele are resistant to diet-induced obesity and also develop abnormal myelination and vacuolation in the central nervous system. To better understand the pathophysiology and relationship of these pleiotropic effects, we further characterized the molecular abnormalities responsible for two additional Atrn alleles, Atrn(mg) and Atrn(mg-L), and examined in parallel the phenotypes of homozygous and compound heterozygous animals. We find that the three alleles have similar effects on pigmentation and neurodegeneration, with a relative severity of Atrn(mg-3J) > Atrn(mg) > Atrn(mg-L), which also corresponds to the effects of the three alleles on levels of normal Atrn mRNA. Animals homozygous for Atrn(mg-3J) or Atrn(mg), but not Atrn(mg-L), show reduced body weight, reduced adiposity, and increased locomotor activity, all in the presence of normal food intake. These results confirm that the mechanism responsible for the neuropathological alteration is a loss--rather than gain--of function, indicate that abnormal body weight in Atrn mutant mice is caused by a central process leading to increased energy expenditure, and demonstrate that pigmentation is more sensitive to levels of Atrn mRNA than are nonpigmentary phenotypes.

[Pulmonary Mycobacterium Kansasii infection in the southern area of Fukuoka prefecture]

Cases of pulmonary infection caused by Mycobacterium kansasii (Mk) in our hospital located at the mid-northern area of the Kyushu district, which is in the southern part of Fukuoka prefecture were evaluated. Mk infection is not so rare in other areas of Japan, such as Tokyo and Kinki district, however, there has been no published report on the disease from the Kyusyu district. Therefore, the frequency and the clinical features of our cases of Mk infection were analyzed. During 17 years from 1982 to 1998, there were 14 patients of Mk infection out of 241 nontuberculous mycobacteriosis (NTM). There were 595 patients of culture-positive pulmonary tuberculosis without prior treatment (Tbc). The proportion of Mk/Tbc was 2.4% and that of Mk/NTM was 5.8%. During the period A (from 1982 to 1994) the ratio of Mk/Tbc was 5/462 (1.1%), while on the other side that of Mk/Tbc during the period B (from 1995 to 1998), it was 9/133 (6.8%), which was significantly (P < 0.01) higher compared with that in the period A. Although the patients of Mk infection in our hospital had been rare until 1994, from the results mentioned above, it was considered that the frequency of Mk infection in our hospital has increased to some extent since 1995. One of the characteristics in our cases was that the ratio of female (42.9%) was relatively high. All the female patients were considered to be compromised hosts. The results of the drug resistance tests were consistent with the other reports in our country. By the combination treatment including rifampicin as the major drug, the negative conversion of culture were obtained within 2 months in all our cases.

Effects of Isopropyl Unoprostone on Melanogenesis in Mouse Epidermal Melanocytes

PURPOSE

To investigate the effects of isopropyl unoprostone (referred to as unoprostone) on melanin synthesis and the nature of melanin.

METHODS

M1 and M2, potential intraocular oxidized metabolites of unoprostone, were added to the culture medium in a cultured immortal line of mouse epidermal melanocytes, melan-a, once a day for 2 weeks at concentrations of 5 nM and 50 nM. Vehicle solution was utilized as a control. The amounts of pyrrole-2,3,5-tricarboxylic acid (PTCA), an oxidized product of eumelanin, and aminohydroxyphenylalanine (AHP), a hydrolyzed product of pheomelanin, were measured by high-performance liquid chromatography.

RESULTS

A 5-nM concentration of M2 significantly increased PTCA production (20.84 +/- 3.17 ng/10(6) cells mean +/- SD) compared with the control (14.58 +/- 4.62 ng/10(6) cells) (P =.04), although other concentrations did not affect the synthesis of PTCA or AHP. A 5-nM concentration of M2 significantly increased the PTCA/AHP (1.86 +/- 0.18) ratio compared with the control (1.37 +/- 0.41) (P =.04). A 50 nM concentration of M2 slightly increased the PTCA/AHP (1.74 +/- 0.58) ratio, but M1 did not affect this ratio.

CONCLUSIONS

These results indicate that M2 affects not only melanogenesis but also the nature of melanin, which could result in unoprostone-generated iridial pigmentation.

Cyclic oscillations in melanin composition within hairs of baboons

The wild-type agouti-banding pattern for hair is well characterized in lower mammals such as mice. The switch between eumelanin and pheomelanin in bands in the hair results from the interaction of alpha-melanocyte stimulating hormone and agouti signal protein through the melanocortin 1 receptor on melanocytes. However, such banding patterns have not been described to date in higher mammals. We now report such 'agouti'-banding patterns that occur in several subspecies of baboons, and characterize those hairs using chemical and immunohistochemical methods. Hair and skin samples were obtained from the dorsa of adult male baboons of different subspecies (Papio cynocephalus hamadryas (PCH) and Papio cynocephalus anubis (PCA)). The hairs were excised with scissors into the gray and the white bands of the PCH subspecies and into the black and the yellow bands of the PCA subspecies, and were analyzed for total melanin, eumelanin, and pheomelanin by spectrophotometric and chemical methods. Hairs in the PCA subspecies oscillate between a eumelanic band (with high melanin content) and a pheomelanic band, while hairs in the PCH subspecies oscillate between a eumelanic band (with low melanin content) and a non-pigmented band. Those chemical data are consistent with the histological appearance of the hair bulbs stained by the Fontana-Masson technique. The difference in the melanin content between PCH and PCA subspecies is most likely related to tyrosinase levels, as suggested by the presence of unpigmented muzzle in the PCH subspecies compared with the black muzzle in the PCA subspecies.

Tissue factor expression and serum level in patients with melanoma does not correlate with disease progression

Not only does tissue factor (TF) play a crucial role in hemostasis and thrombosis, but it is also involved in tumor progression and metastatic potency in some malignant tumors. We evaluated the clinical relevance of TF expression in melanocytic tumors and TF serum level in patients with malignant melanoma. TF expression in benign and malignant melanocytic lesions was examined by immunoperoxidase staining in 20 nevi, 41 primary, and 24 metastatic melanoma lesions. TF was detected in 94, 95, and 100% of these lesions, respectively. The staining pattern was membranous and cytoplasmic both in nevi and melanoma cells. This finding was confirmed by western blot analysis using cultured human melanocytes, nevi cells, and melanoma cell lines. TF was also expressed on blood vessels in benign and malignant melanocytic lesions. Expression of TF in primary melanoma lesions was not associated with any clinicopathological variables. In addition, the serum level of TF was elevated in 14% of patients with melanoma; however, it was not correlated with disease progression. These results suggest that TF was ubiquitously expressed in melanocytic cells and its expression was not correlated with disease progression and/or metastatic potency of melanoma cells.

Chemical analysis of melanins and its application to the study of the regulation of melanogenesis

Melanins are difficult to characterize because of their intractable chemical properties, the heterogeneity in their structural features, and the lack of methods to split melanin polymers into monomer units. To overcome this difficulty, we developed a rapid and sensitive method for quantitatively analyzing eumelanin and pheomelanin in biological samples that is based on the formation of pyrrole-2,3,5-tricarboxylic acid and/or aminohydroxyphenylalanine followed by HPLC determination. The method has been applied to the study of melanogenesis. The results summarized in this review are: 1) Biochemical studies show that in the process of mixed melanogenesis, cysteinyldopas are produced first, which are then oxidized to give pheomelanin; following cysteine depletion, eumelanin is then deposited on the preformed pheomelanin. 2) In vitro and in vivo studies show that tyrosinase activity is the most important factor that regulates the switch of melanogenesis, with lower tyrosinase activities favoring pheomelanogenesis; further suppression of melanogenesis results in a lack of pigment production. 3) In cultured melanocytes, the concentrations of tyrosine and cysteine, and their ratio in the medium, are important in determining the concentrations of eumelanin and pheomelanin produced and their ratio in the cells. In conclusion, our HPLC microanalytical method for characterizing eumelanin and pheomelanin has become a useful tool for the study of melanogenesis.

Effects of peptide dimerization on pore formation: Antiparallel disulfide-dimerized magainin 2 analogue

To elucidate the effects of peptide dimerization on pore formation by magainin 2 (MG2), a covalently linked antiparallel dimer of the MG2 analogue [(F5Y, L6C, F16W, I20C-MG2)(2): II] was synthesized based on the dimer structure revealed by our NMR study. The interactions of the dimer with lipid bilayers were investigated by CD and fluorescence in comparison with a monomer analogue (F5Y, F16W-MG2: I). Similar to I, II was found to form a peptide-lipid supramolecular complex pore accompanied with lipid flip-flop and peptide translocation. The pore formed by II was characterized by a slightly larger pore diameter and a threefold longer lifetime than that of I, although the pore formation rate of the dimer was lower than that of the monomer. The coexistence of the dimer and the monomer exhibited slight but significant synergism in membrane permeabilization, which was maximal at a monomer/dimer ratio of 3. Therefore, we concluded that a pentameric pore composed of one pore-stabilizing dimer and three monomers maximized the overall leakage activity in keeping with our kinetic prediction.