PubMed Health⌕ Search

Biomedical subjects

K Arikawa

Publications and source records attributed to K Arikawa.

At least 19 recordsLinked to original sources
PubMed2006

Light on the moth-eye corneal nipple array of butterflies.

The outer surface of the facet lenses in the compound eyes of moths consists of an array of excessive cuticular protuberances, termed corneal nipples. We have investigated the moth-eye corneal nipple array of the facet lenses of 19 diurnal butterfly species by scanning electron microscopy, transmission electron microscopy and atomic force microscope, as well as by optical modelling. The nipples appeared to be arranged in domains with almost crystalline, hexagonal packing. The nipple distances were found to vary only slightly, ranging from about 180 to 240 nm, but the nipple heights varied between 0 (papilionids) and 230 nm (a nymphalid), in good agreement with previous work. The nipples create an interface with a gradient refractive index between that of air and the facet lens material, because their distance is distinctly smaller than the wavelength of light. The gradient in the refractive index was deduced from effective medium theory. By dividing the height of the nipple layer into 100 thin slices, an optical multilayer model could be applied to calculate the reflectance of the facet lenses as a function of height, polarization and angle of incidence. The reflectance progressively diminished with increased nipple height. Nipples with a paraboloid shape and height 250 nm, touching each other at the base, virtually completely reduced the reflectance for normally incident light. The calculated dependence of the reflectance on polarization and angle of incidence agreed well with experimental data, underscoring the validity of the modelling. The corneal nipples presumably mainly function to reduce the eye glare of moths that are inactive during the day, so to make them less visible for predators. Moths are probably ancestral to the diurnal butterflies, suggesting that the reduced size of the nipples of most butterfly species indicates a vanishing trait. This effect is extreme in papilionids, which have virtually absent nipples, in line with their highly developed status. A similar evolutionary development can be noticed for the tapetum of the ommatidia of lepidopteran eyes. It is most elaborate in moth-eyes, but strongly reduced in most diurnal butterflies and absent in papilionids.

Animals↗
PubMed2004

Butterfly wing colours: scale beads make white pierid wings brighter.

The wing-scale morphologies of the pierid butterflies Pieris rapae (small white) and Delias nigrina (common jezabel), and the heliconine Heliconius melpomene are compared and related to the wing-reflectance spectra. Light scattering at the wing scales determines the wing reflectance, but when the scales contain an absorbing pigment, reflectance is suppressed in the absorption wavelength range of the pigment. The reflectance of the white wing areas of P. rapae, where the scales are studded with beads, is considerably higher than that of the white wing areas of H. melpomene, which has scales lacking beads. The beads presumably cause the distinct matt-white colour of the wings of pierids and function to increase the reflectance amplitude. This will improve the visual discrimination between conspecific males and females.

Animals↗
PubMed2004

Action spectrum of foraging behavior of the Japanese yellow swallowtail butterfly, Papilio xuthus.

This paper describes the action spectrum of foraging behavior of a butterfly, Papilio xuthus. We first established an experimental protocol to evaluate learning and discrimination of monochromatic light by the butterflies. We trained butterflies to feed on sucrose solution at the window illuminated with certain monochromatic light produced through a monochromator. After confirming that they learned the monochromatic light, after 10 days of training, we tested the butterflies one by one. We presented training wavelengths for each individual at different intensities, and recorded whether they perform foraging behavior under freely-flying as well as tethered conditions. Freely-flying butterflies responded to light by visiting the window and searching for nectar around it, whereas tethered butterflies responded by extending their proboscides towards the window. The light intensity required to elicit 50% response for each tested monochromatic light was plotted. The resulting action spectrum for the visit was rather flat with the maximum sensitivity a 420 nm, whereas the spectrum for the proboscis extension had prominent peaks at 380, 500 and 600 nm. The difference in action spectra indicates that the visit and the proboscis extension are controlled by two independent mechanisms at least in part.

Animals↗
PubMed2003

Spectral organization of the eye of a butterfly, Papilio.

This review outlines our recent studies on the spectral organization of butterfly compound eyes, with emphasis on the Japanese yellow swallowtail butterfly, Papilio xuthus, which is the most extensively studied species. Papilio has color vision when searching for nectar among flowers, and their compound eyes are furnished with six distinct classes of spectral receptors (UV, violet, blue, green, red, broadband). The compound eyes consist of many ommatidia, each containing nine photoreceptor cells. How are the six classes of spectral receptors arranged in the ommatidia? By studying their electrophysiology, histology, and molecular biology, it was found that the Papilio ommatidia can be divided into three types according to the combination of spectral receptors they contain. Different types of ommatidia are distributed randomly over the retina. Histologically, the heterogeneity appeared to be related to red or yellow pigmentation around the rhabdom. A subset of red-pigmented ommatidia contains 3-hydroxyretinol in the distal portion, fluorescing under UV epi-illumination. The red, yellow and fluorescing pigments all play crucial roles in determining the spectral sensitivities of receptors. Spectral heterogeneity and random array of ommatidia have also been found in other lepidopteran species. Similarities and differences between species are also discussed.

Animals↗
PubMed2002

The photoreceptor localization confirms the spectral heterogeneity of ommatidia in the male small white butterfly, Pieris rapae crucivora.

The compound eye of Pieris rapae crucivora contains ventrally three types of histologically distinct ommatidia. An ommatidium contains nine photoreceptors, four of which (R1-4) construct the distal tier of the rhabdom. We determined the sensitivity spectra of the R1-4 distal photoreceptors in each type of ommatidia by intracellular electrophysiology and identified UV, blue, double-peaked blue, green, and a green receptor with depressed sensitivity in the violet. We localized these receptors in each type of ommatidia by injecting dye after the recording. In type I ommatidia the R1 and R2 cells are UV and blue receptors. When R1 is UV sensitive, R2 is always blue sensitive, or vice versa. R3 and R4 in type I are both green receptors. In type II, R1 and R2 are both double-peaked blue receptors and R3 and R4 are both green receptors with depressed sensitivity in the violet. In type III, R1 and R2 are both UV, and R3 and R4 are green receptors. The double-peaked blue, and green receptors with depressed sensitivity in the violet in type II ommatidia have depressed sensitivity at 420 nm, which is probably due to the filtering effect of a fluorescing material present in the type II ommatidia. Spectral heterogeneity of ommatidia seems to be a common design of insect compound eyes.

Animals↗
PubMed2002

An outbreak of gastroenteritis in Osaka, Japan due to Escherichia coli serogroup O166:H15 that had a coding gene for enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1).

In an outbreak of gastroenteritis on 23 July 1996, in Osaka, Japan, 54 of 91 persons who had attended a meeting the previous day became ill. Escherichia coli O166:H15 was isolated from stool specimens of patients (29/33, 88%). Laboratory tests for other bacterial pathogens and viruses were negative. The E. coli 0166 organisms did not adhere to HEp-2 cells in a localized, diffuse, or enteroaggregative manner. The organisms did not express known enterotoxigenic E. coli (ETEC) colonization factors. In polymerase chain reaction tests, the bacteria did not have coding genes for shigatoxin of enterohemorrhagic E. coli (EHEC), heat-labile, or heat-stable enterotoxin of ETEC, attachment and effacement (eaeA) of EPEC, or invasion (invE) of enteroinvasive E. coli (EIEC). Consequently, they could not be assigned to any of the recognized diarrhoeagenic groups of E. coli: EPEC, ETEC, EHEC, EIEC, enteroaggregative E. coli (EAggEC), or diffusely adhering E. coli. However, the organisms possessed the EAggEC heat-stable enterotoxin (EAST1) gene. To our knowledge, this is the first report of an outbreak caused by E. coli that did not have well-characterized virulence genes other than EAST1. The isolates showed the same DNA banding pattern in pulsed-field gel electrophoresis after digestion with the restriction enzymes XbaI or NotI. Three O166:H15 strains isolated from two sporadic cases and another outbreak during 1997-8 were distinct, indicating that multiple clones have spread already. We propose that diarrhoeal specimens should be examined for E. coli possessing the EAST1 gene.

Base Sequence↗
PubMed2002

Accuracy of portable infusers under hyperbaric oxygenation conditions.

Three types of portable infusers with different infusion mechanisms were evaluated with regard to their accuracy during a hyperbaric oxygenation protocoL The power driving the pump is provided by either a balloon, a spring or a vacuum mechanism. Performance during hyperbaric oxygenation (HBO) varied between the devices, probably due to the difference in driving mechanism. Flow delivery by the vacuum type infuser is substantially affected by HBO. Doubling the ambient pressure approximately doubled flow delivery from the vacuum type device. We suggest that other devices are more suitable for use in this clinical situation. We conclude that it is desirable to check the performance of any infuser intended for use during hyperbaric oxygenation and to be mindful of potential differences among such devices.

Equipment Design↗
PubMed2001

Retinal regionalization and heterogeneity of butterfly eyes.

The regional characteristics of the eyes of butterflies from different families have been surveyed using epi-illumination microscopy, utilizing the eyeshine visible due to the tapetum situated proximally to the rhabdom. All butterflies studied have a high spatial acuity in the frontal region. The facet diameter varies slightly across the eye, and the interommatidial angle and the eye parameter p are especially large dorsally. Whereas the ommatidial lattice is generally highly regular, the eyeshine colours distinctly depend on the species. Sometimes the eyeshine is locally uniform, but often it is heterogeneous. It is hypothesized that the regional characteristics as well as the local heterogeneity are adaptations that optimize spectral discrimination.

Animals↗
PubMed2001

[Clinical significance of eosinophilic cationic protein in serum and bronchoalveolar lavage fluid of adult patients with mycoplasmal pneumonia].

Pathogenic mechanisms of mycoplasmal pneumonia is not fully understood at present though some kind of cell-mediated hypersensitivity is closely related to its mechanisms. Though eosinophilia in peripheral blood are sometimes revealed in patient with mycoplasmal pneumonia, it is not unclear whether eosinophils related to its pathogenesis, or not. We evaluated the clinical significance of ECP in serum and BAL fluid in patients with mycoplasmal pneumonia. The diagnosis of mycoplasmal pneumonia was confirmed both by serological diagnosis from paired serum and by the polymerase chain reaction (PCR) methods using specific primers of the Mycoplasma pneumoniae for detecting specific DNA from bronchial washing fluids. ECP level in serum were measured in 27 patients (11 male, 16 female, average age 31.7 yo) with mycoplasmal pneumonia by ELISA methods. ECP level in BALF were also measured in ten of all patients. The level of ECP in serum was high in 17 cases (63%) of the total cases. In addition the level of ECP in BALF was also high in all tested patients (10 cases). There was a correlation between serum ECP level and days from onset. There was also a correlation between serum ECP level and WBC counts, the degree of PaO2. These results suggested that ECP derived from activated eosinophils in the lung might in part play a role in the pathogenesis of mycoplasmal pneumonia.

Adult↗
PubMed2001

Polarisation-dependent colour vision in Papilio butterflies.

Butterflies of the genus Papilio have polarisation-sensitive photoreceptors in all regions of the eye, and different spectral types of receptor are sensitive to different e-vector orientations. We have studied the consequences of this eye design for colour vision in behavioural tests and find that Papilio spp. see false colours due to the polarisation of light. They discriminate between vertically and horizontally polarised light of the same colour in the contexts of oviposition and feeding. The discrimination depends on the spectral composition of the stimuli. In the blue and probably in the green range, discrimination does not depend on intensity. However, colour discrimination is influenced by polarisation. Thus, colour and polarisation processing are not separated in the visual system of Papilio spp. From these results, we propose hypotheses about which photoreceptors contribute to colour vision in Papilio spp. and what adaptational value such a system might have for the butterflies. Finally, we give examples for other eyes that have a similar structure.

Animals↗
PubMed2001

[Extracranial metastasis of glioblastoma to the lung and heart with a histological resemblance to small cell carcinoma of the lung: an autopsy case].

An autopsy case of small cell glioblastoma, showing multiple extracranial metastases, is reported with special reference to histopathological differentiation from metastatic small cell carcinoma. Widely spread lesions in the bilateral lungs were developed after an operation and chemo-radiotherapy for glioblastoma, and the lung lesions led to fatal respiratory failure. Postmortem examination revealed multiple tumors in the lung, lymph nodes, and the heart, as well as local invasion of the primary tumor to the dura, skull, and the scalp. The mechanism of extracranial metastasis of brain tumor is discussed.

Adult↗
PubMed2000

The accuracy and reliability of an infusion pump (STC-3121; Terumo Inst., Japan) during hyperbaric oxygenation.

We evaluated the accuracy of delivery of one type of infusion pump at three nominal flow rates under two environmental pressures (measured in atmospheres absolute, ATA), one of which is used for hyperbaric oxygenation. Overall, we observed significant differences between the two different pressures (1 ATA and 2 ATA). Changes in the rate of delivery of between about -4% and +2% were observed over the time course of hyperbaric oxygenation, and the inter-group difference was significant in the phases in which pressure was changing. The effect produced by 2 ATA was statistically significant but small, and its influence is likely to be negligible during practical hyperbaric oxygenation therapy. Thus, it would seem that this type of pump would deliver reliably at the nominal rate during hyperbaric oxygenation at these levels.

Humans↗
PubMed2000

Ultraviolet and violet receptors express identical mRNA encoding an ultraviolet-absorbing opsin: identification and histological localization of two mRNAs encoding short-wavelength-absorbing opsins in the retina of the butterfly Papilio xuthus.

This paper describes the primary structures of two opsins of short-wavelength-absorbing visual pigments deduced from the mRNA sequences in the retina of the Japanese yellow swallowtail butterfly Papilio xuthus. A phylogenetic analysis of the amino acid sequences indicates that one of these visual pigments is of the ultraviolet-absorbing type and that the other is of the blue-absorbing type. We identified the photoreceptor cells that express these mRNAs by histological in situ hybridization. The mRNA of the ultraviolet type is expressed in two distinct photoreceptor types previously identified as ultraviolet and violet receptors, providing the first molecular biological evidence that different types of spectral receptor probably express a visual pigment with an identical amino acid sequence. The mRNA of the blue type is expressed exclusively in cells classified as blue receptors.

Amino Acid Sequence↗
PubMed2000

Colour constancy in the swallowtail butterfly Papilio xuthus.

We have recently shown that the Japanese yellow swallowtail butterfly Papilio xuthus uses colour vision when searching for food. In the field, these butterflies feed on nectar provided by flowers of various colours not only in direct sunlight but also in shaded places and on cloudy days, suggesting that they have colour constancy. Here, we tested this hypothesis. We trained newly emerged Papilio xuthus to feed on sucrose solution on a paper patch of a certain colour under white illumination. The butterflies were then tested under both white and coloured illumination. Under white illumination, yellow- and red-trained butterflies selected the correctly coloured patch from a four-colour pattern and from a colour Mondrian collage. Under four different colours of illumination, we obtained results that were fundamentally similar to those under white illumination. Moreover, we performed critical tests using sets of two similar colours, which were also correctly discriminated by trained butterflies under coloured illumination. Taken together, we conclude that the butterfly Papilio xuthus exhibits some degree of colour constancy when searching for food.

Animals↗
PubMed2000

[Myocardial ischemia during cesarean section in a patient with placental abruption].

A 27-year-old woman (38 week pregnant) was admitted to an obstetric hospital with an acute severe abdominal pain. At that time, the fetal heart sound was not audible. The diagnosis of placental abruption was made and she underwent an emergency cesarean section (C/S) under general anesthesia. She had anemia which became worse in the first few hours after C/S, requiring blood transfusion. ST depression was also present in the ECG during this period. Subsequently, we found an increase in myocin light chain, but not in troponin-T. On the 2nd postoperative day, pulmonary edema appeared and DIC was suspected. We treated her with nitrates, diuretics, protease inhibitors and oxygen by mask. She was discharged on 14th postoperative day with no other complications. Cardiac echogram showed no abnormalities, but a borderline change was seen in her exercise ECG. Depression of the ST segment has been reported in C/S patients, but this does not indicate myocardial ischemia (MI) nor treatment is necessary in most cases. In our case, the diagnosis was not conclusive, but in view of the risks associated with MI, patients with placental abruption should be managed strictly as if they have MI.

Abruptio Placentae↗
PubMed1999

An ultraviolet absorbing pigment causes a narrow-band violet receptor and a single-peaked green receptor in the eye of the butterfly Papilio.

The distal photoreceptors in the tiered retina of Papilio exhibit different spectral sensitivities. There are at least two types of short-wavelength sensitive receptors: an ultraviolet receptor with a normal spectral shape and a violet receptor with a very narrow spectral bandwidth. Furthermore, a blue receptor, a double-peaked green receptor and a single-peaked green receptor exist. The violet receptor and single-peaked green receptor are only found in ommatidia that fluoresce under ultraviolet illumination. About 28% of the ommatidia in the ventral half of the retina exhibit the UV-induced fluorescence. The fluorescence originates from an ultraviolet-absorbing pigment, located in the most distal 70 microns of the ommatidium, that acts as an absorption filter, both for a UV visual pigment, causing the narrow spectral sensitivity of the violet receptor, and for a green visual pigment, causing a single-peaked green receptor.

Animals↗
PubMed1999

[Case of varicella-zoster pneumonia with bronchioalveolar lavage confirmed by the detection of VZV DNA in the bronchial washing by the polymerase chain reaction].

A 32-year old male was admitted to our hospital complaining of cough, fever, and skin eruptions. He was coctacted with a child who had chickenpox 3 weeks before the onset. He showed the elevating of antibody to varicella-zoster virus. Despite of the administration of Acyclovir for four days, cough was not relieved and a chest X-ray film showed infiltrative shadow in right middle lobe of the lung. Bronchoscopic examination revealed vasicle and edema, and the varicella-zoster virus (VZV) DNA was detected in the bronchoalveolar lavage by the polymerase chain reaction. The patient in first case confirmed by the virus DNA in the bronchial washing by the PCR.

Adult↗