Biomedical subjects
Publications and source records attributed to A Maeda.
Disease activity in Japanese sarcoidosis patients is generally mild. However, the pulmonary sarcoidosis coexisting with connective tissue disease is likely to be progressive. We report here three cases of sarcoidosis coexisting with connective tissue diseases, who developed pulmonary manifestations from stage II to stage III.
Total intravenous anesthesia with propofol, fentanyl and ketamine (PFK) was given to two patients complicated with myotonic dystrophy. Case-1: A 42-year-old female underwent a hemithyroidectomy. Anesthesia was induced slowly with intravenous ketamine 20 mg and propofol 60 mg. Her tracheal intubation was performed smoothly without any muscle relaxants. Anesthesia was maintained with propofol infusion of 5 mg.kg-1.h-1, ketamine infusion of 0.3 mg.kg-1.h-1 and fentanyl 200 micrograms in total. She regained consciousness 20 minutes after the end of propofol infusion, and 15 minutes later, her trachea was extubated without any troubles. Case-2: A 41-year-old female underwent a removal of left parotid tumor. Anesthesia was induced slowly with ketamine 40 mg and propofol 100 mg intravenously. Anesthesia was maintained with propofol infusion of 5-10 mg.kg-1.h-1, ketamine infusion of 0.5 mg.kg-1.h-1 and fentanyl 350 micrograms in total. No muscle relaxant was used through the surgical procedure. Emergence from anesthesia was observed 10 minutes after the end of propofol infusion and her trachea was extubated. When a nasogastric tube was pulled out, her respiration stopped suddenly and she was intubated again only for two hours without any troubles. In both cases their serum CPK levels and rectal temperatures were very stable. PFK method would be a choice for patients with myotonic dystrophy.
This study was conducted to determine whether elderly subjects with visual impairment differ in the performance of complex activities in daily living from those without visual impairment. The study subjects were residents in two homes for the aged in Japan, and consisted of 37 elderly people with visual impairment, and 42 elderly people, serving as controls; ages ranged from 64 to 95 years. Complex activities of the subjects were ascertained by interview using a 46-item questionnaire. The visually impaired elderly had lower performance levels for telephone use (p = 0.007), shopping (p = 0.049), cleaning up one's room (p = 0.001), and utilization of medical facilities (p = 0.001) in instrumental ADL (IADL); for interest in TV or radio (p = 0.004) and religious faith (p = 0.042) in "enriching activities"; and for visiting behaviors (p < 0.05) in "social role". The performances of complex activities by the elderly with visual impairment were diminished in specific categories, but not overall, and this may be attributable to poor mobility and/or more passive attitudes in their daily activities.
PURPOSE: The Royal College of Surgeons (RCS) rat has been extensively characterized as a model for inherited retinal dystrophy such as retinitis pigmentosa. In the present study, compositions of retinal proteins were compared between RCS (rdy-/-) and control (rdy+/+) rats during progression of the disease to understand the molecular pathologic course of the retinal degeneration. METHODS: Protein mapping was performed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) or two-dimensional (2D)-PAGE using whole retinas or rod outer segments (ROS) obtained by a sucrose-density gradient centrifugation method from RCS or control rats at the age of 3 to 8 weeks. RESULTS: 2D-PAGE showed that retinal proteins of RCS rats were generally less abundant than those of the control animals and that the difference became more evident with aging. However, no significant difference was observed in the protein-mapping patterns in 2D-PAGE between RCS and control rats in any ages tested. Analysis by SDS-PAGE of ROS proteins and by western blot using antibodies against opsin, rhodopsin kinase (RK), recoverin, or arrestin demonstrated that a 20-kDa protein and RK were selectively less abundant in RCS than in control rats. Edman sequence analysis of the proteolytic peptides obtained by in-gel digestion of the corresponding protein band using endoproteinase Lys C identified the 20-kDa protein as alphaA-crystallin. Reverse transcription-polymerase chain reaction confirmed selective low levels of mRNA expressions of alphaA-crystallins and RK in RCS rats. CONCLUSIONS: This study demonstrates that decreased expression of alphaA-crystallins and RK in RCS rats, may have significant roles in the development of retinal dystrophy.
A 22-year-old woman with fever and bleeding tendency was given a diagnosis of acute promyelocytic leukemia (APL) on the basis of laboratory findings including a WBC count of 106 x 10(3)/microliter (90% blasts) and a platelet count of 1.6 x 10(4)/microliter. Induction therapy was started with all-trans retinoic acid (ATRA) and cytotoxic chemotherapy. After the patient achieved complete remission, ATRA was discontinued and consolidation chemotherapy was started. However, 4 months after onset, leukemic blasts were detected in cerebrospinal fluid. Temporal central nervous system remission was induced by intrathecal chemotherapy only. However, 2 months later, multiple focal mass lesions had developed in the brain. ATRA (45 mg/m2) was restarted together with multiple intrathecal injections of anticancer drugs, and a third remission was achieved. It is conceivable that the incorporation of ATRA in induction chemotherapy is related to the development of this rather rare complication of APL. The outcome in this case suggested orally administered ATRA may be effective in treating brain metastasis of APL.
PURPOSE: In a previous study, both recoverin and heat shock cognate protein 70 (hsc 70) were found as autoantigens recognized by sera from four patients with cancer-associated retinopathy (CAR). This observation suggested that autoimmune reactions against recoverin and hsc 70 might be involved together in the pathogenesis of CAR. The purpose of the present study is to investigate the effects of these autoantibodies on retinas in vivo. METHODS: Functional and morphologic properties of the retinas were evaluated after anti-recoverin and/or anti-hsc 70 antibodies were intravitreously injected into Lewis rats' eyes. RESULTS: Responses in electroretinogram (ERG) of eyes penetrated with anti-hsc 70 antibody were comparable with the control, but those with anti-recoverin antibody were remarkably reduced during the 3-week period after the injection. Such anti-recoverin antibody-induced reduction was significantly enhanced by copenetration with anti-hsc 70 antibody. Immunofluorescence microscopy demonstrated that after intravitreal injection, anti-recoverin antibody penetrated toward the outer nuclear layer (ONL) and outer segments within 12 to 24 hours, and the presence of the antibody in the retina diminished during the next few days. Histopathology revealed significant thinning of the ONL and inner nuclear layer (INL) in the affected retina in comparison with the control. Throughout the ONL and INL, apoptotic cells were recognized by TdT-dUTP terminal nick-end labeling. The antibody-induced retinal dysfunction was effectively treated by administrations of either corticosteroid or cyclosporin A. CONCLUSIONS: These observations suggest that anti-recoverin- and anti-hsc 70 antibody-induced retinal dysfunction in Lewis rat is a good model to study the pathophysiology of CAR.
There are no guidelines regarding the treatment of pulmonary sarcoidosis. Generally, oral corticosteroids are considered the first-line treatment for symptomatic patients with pulmonary sarcoidosis. We report here two Japanese cases with pulmonary sarcoidosis who demonstrated sequential evolution from radiographic stage I to III within five years. Although these two cases had no symptoms, persistent, progressive pulmonary involvements were observed on chest X-ray. Considering the effectiveness of corticosteroids on patients with radiographic type II or III sarcoidosis reported by the British Thoracic Society, corticosteroid therapy might be a choice even in asymptomatic cases, if they demonstrate developing pulmonary involvement.
The 24-hour home help services that provide day and night care services at home becomes a public health interest in Japan. The purpose of this study was to evaluate the system of 24-hour home help services in a community that has successfully developed it. Participants of this focus group interview were home helpers who were actually engaged in 24-hour home help services in A town of Akita Prefecture. The focus group session was tape-recorded and the tapes were transcribed. The transcripts were evaluated and summarized in order to identify major categories and number of descriptive statements in each category. The results were as follows. First, the home helpers considered that their system of 24-hour home help services could be technically transferred to other communities in Japan. Secondary, the political leadership and the democratic system of community participation were the essential elements for promoting the 24-hour home help services. Thirdly, the regular meetings for discussion about cases and opinion exchanges were required more extensively in the future.
Cysteinyl leukotrienes (cysLTs) are considered to be important mediators involved in bronchial asthma and the ensuing eosinophilic inflammation. We evaluated the effects of pranlukast, a potent and selective cysLT receptor antagonist, on the clinical course and serum eosinophil cationic protein (ECP) levels of 10 asthmatic patients. A four-week administration of pranlukast increased the morning peak expiratory flow (PEF) (p = 0.007) and decreased as-needed beta 2-agonist use (p = 0.021). Changes in the morning PEF inversely correlated with those in the serum ECP levels (r = -0.80, p = 0.0057). These results suggest that cysLTs are important mediators involved in eosinophilic inflammation, a major pathophysiologic feature of bronchial asthma in humans.
A 64-year-old man underwent a medical checkup in May 1996 and was evaluated as class V using sputum cytology. Chest X-ray examination, bronchoscopy and chest computed tomography (CT) demonstrated no abnormalities. Thereafter, the patient was followed up with chest X-ray, bronchoscopy and chest CT at 3-month intervals. In December 1996, chest CT showed an increased density at the mediastinal side of the left upper bronchus, B1+2. There were no findings on bronchoscopy, but subsequent exfoliative cytology demonstrated keratinized malignant cells in samples obtained from left upper bronchus, B1+2. Although, it was difficult to identify localization of the tumor, left upper lobectomy was performed and the diagnosis of squamous cell carcinoma in situ was finally made. Here, we report on the course of this patient and discuss the diagnostic usefulness of sputum cytology as well as the pathogenesis of lung squamous cell carcinoma.
Difference Fourier transform infrared spectra were recorded between mutants of rhodopsin and their batho products. The pigments studied were single and combined mutants of intramembrane residues of bovine rhodopsin: Asp83, Glu113, Gly120, Gly121, and Glu122. Previous studies [Nagata, T., Terakita, A., Kandori, H., Kojima, D., Shichida, Y., and Maeda, A. (1997) Biochemistry 36, 6164-6170] showed that one of the water molecules which undergoes structural changes in this process forms hydrogen bonds with Glu113 and the Schiff base, and that another water molecule is linked to this structure through the peptide backbone. The present results show that this water molecule is located at the place that is affected by the replacements of Asp83 and Gly120 but only slightly by Gly121 and not at all by Glu122. Asp83 and Gly120 are close to each other, in view of the observations that the carboxylic C=O stretching vibration of Asp83 is affected by the G120A replacement and that each replacement affects the common peptide carbonyl groups. Our results suggest that these residues in the middle of helices B and C are linked-through a hydrogen-bonding network composed of water and the peptide backbone-with the region around Glu113.
Structural changes in the complex formed between photolyzed bovine rhodopsin and a synthetic 11-mer peptide corresponding to the C-terminal region of the transducin alpha-subunit (Gtalpha) were analyzed by means of Fourier transform infrared spectroscopy. A complex with a protonated Schiff base appears at the beginning, accompanying the formation of an alpha-helix. This complex evolves into another which abolishes the original structure but retains the protonated Schiff base. This complex exhibits the same spectral shape as that of the final stable complex with an unprotonated Schiff base. The Fourier transform infrared spectrum for the formation of this final complex was compared to that with transducin [Nishimura, S., Sasaki, J., Kandori, H., Matsuda, T., Fukada, Y., and Maeda, A. (1996) Biochemistry 35, 13267-13271]. A large part of the frequency shifts of the peptide carbonyl vibrations which form upon complex formation with transducin but are absent with the synthetic 11-mer peptide must be structural changes in other sites, such as the nucleotide binding site in Gtalpha. The peptide, like transducin, shows the perturbation of a carboxylic acid in an extremely apolar environment. Some of the changes in the peptide backbone remain in the complex formed with the peptide. These are due to sites where rhodopsin interacts with the C-terminal region of Gtalpha. Specifically, the labeling of the peptide amide corresponding to Leu349 of transducin by 15N reveals weakening of the hydrogen bond of the peptide N-H of Leu349 and/or distortion of a peptide bond between Gly348 and Leu349 upon complex formation.
NMR analysis of d(C4T) showed the slow exchange between two distinct tetramers (each fully symmetric) in solution. For one tetramer, NOE cross-peak patterns characteristic of an i-motif structure (H1'-H1' and H6-H1'/H1'-H6) were observed between C1 and T5, indicating that this tetramer takes a completely intercalated conformation where the T5 residue is stacked on the C1.C1(+) pair of the other duplex (S-form). The other was found to be a tetramer in which one of the duplexes is shifted by one nucleotide unit (R-form), resulting in nonstacking 3' end thymidine residues and an equal number of stacked C.C+ pairs to that of the S-form. The same spectral features were observed for d(C3T) but neither for d(TC3) nor d(TC4), indicative of the critical role of the position of the thymidine residue in the tetrad isomerization. From NMR denaturation profiles, the S-forms were found to be more stable than the R-forms, and the linear relationship between the logarithm of the equilibrium constant (K = [tetramer]/[single]4) and the inverse of temperature (1/T) was confirmed for both forms, indicating conformity to the two-state transition model. Both enthalpy and entropy values of the formation of the S-form from four single strands were more negative than those of the R-form. The enthalpy term should contribute to the stabilization of the S-forms at low temperatures. The difference of the free energy values [DeltaG degrees(S-form) - DeltaG degrees(R-form)] was found to be -2.1 and -2.7 kJ.mol-1 at 20 degreesC for d(C4T) and d(C3T), respectively, explaining the higher stability of the S-forms. With increasing temperature, these two topologies were found to comparably exist at equilibrium in solution with slow exchange via dissociation to the single strands. A biological role of this topological isomerization is also suggested.
Paired immunoglobulin-like receptor (PIR)-A and PIR-B possess similar ectodomains with six immunoglobulin-like loops, but have distinct transmembrane and cytoplasmic domains. PIR-B bears immunoreceptor tyrosine-based inhibitory motif (ITIM) sequences in its cytoplasmic domain that recruit Src homology (SH)2 domain-containing tyrosine phosphatases SHP-1 and SHP-2, leading to inhibition of B and mast cell activation. In contrast, the PIR-A protein has a charged Arg residue in its transmembrane region and a short cytoplasmic domain that lacks ITIM sequences. Here we show that Fc receptor gamma chain, containing an immunoreceptor tyrosine-based activation motif (ITAM), associates with PIR-A. Cross-linking of this PIR-A complex results in mast cell activation such as calcium mobilization in an ITAM-dependent manner. Thus, our data provide evidence for the existence of two opposite signaling pathways upon PIR aggregation. PIR-A induces the stimulatory signal by using ITAM in the associated gamma chain, whereas PIR-B mediates the inhibitory signal through its ITIMs.
TNF-alpha is implicated in the initiation of cytokine cascades in various inflammatory settings. To assess the interactions of multiple cytokines at the level of inflammatory effector cells, we examined the effects of TNF-alpha on the expression of two IL-8Rs (CXCR1 and CXCR2) on polymorphonuclear leukocytes (PMNs). TNF-alpha decreased the surface expression of CXCR2 in a dose- and time-dependent manner. In contrast, CXCR1 expression was not affected by TNF-alpha. The release of CXCR2 into the supernatant of TNF-alpha-treated PMNs was detected by immunoblotting and immuno-slot-blot analyses, suggesting that the down-regulation of CXCR2 was caused mainly by shedding from the cell surface. The CXCR2 down-regulation was inhibited by PMSF and aprotinin, supporting the hypothesis that the shedding was mediated by serine protease(s). The intracellular Ca2+ mobilization and chemotaxis in response to IL-8 were suppressed by the pretreatment of PMNs with TNF-alpha, indicating that the decrease in CXCR2 was reflected in the decreased functional responses to IL-8. In contrast, the O2- release, which is mediated by CXCR1, was not suppressed by TNF-alpha. The treatment of whole blood with TNF-alpha also caused a significant reduction in CXCR2 and markedly suppressed intracellular Ca2+ mobilization and chemotaxis in response to IL-8, while enhancing the O2- release. These findings suggest that TNF-alpha down-regulates CXCR2 expression on PMNs and modulates IL-8-induced biologic responses, leading to the intravascular retention of PMNs with an enhanced production of reactive oxygen metabolites.
Characterization of mammalian homologues of Drosophila TRP proteins, which induce light-activated Ca2+ conductance in photoreceptors, has been an important clue to understand molecular mechanisms underlying receptor-activated Ca2+ influx in vertebrate cells. We have here isolated cDNA that encodes a novel TRP homologue, TRP5, predominantly expressed in the brain. Recombinant expression of the TRP5 cDNA in human embryonic kidney cells dramatically potentiated extracellular Ca2+-dependent rises of intracellular Ca2+ concentration ([Ca2+]i) evoked by ATP. These [Ca2+]i transients were inhibited by SK&F96365, a blocker of receptor-activated Ca2+ entry, and by La3+. Expression of the TRP5 cDNA, however, did not significantly affect [Ca2+]i transients induced by thapsigargin, an inhibitor of endoplasmic reticulum Ca2+-ATPases. ATP stimulation of TRP5-transfected cells pretreated with thapsigargin to deplete internal Ca2+ stores caused intact extracellular Ca2+-dependent [Ca2+]i transients, whereas ATP suppressed [Ca2+]i in thapsigargin-pretreated control cells. Furthermore, in ATP-stimulated, TRP5-expressing cells, there was no significant correlation between Ca2+ release from the internal Ca2+ store and influx of extracellular Ca2+. Whole-cell mode of patch-clamp recording from TRP5-expressing cells demonstrated that ATP application induced a large inward current in the presence of extracellular Ca2+. Omission of Ca2+ from intrapipette solution abolished the current in TRP5-expressing cells, whereas 10 nM intrapipette Ca2+ was sufficient to support TRP5 activity triggered by ATP receptor stimulation. Permeability ratios estimated from the zero-current potentials of this current were PCa:PNa:PCs = 14.3:1. 5:1. Our findings suggest that TRP5 directs the formation of a Ca2+-selective ion channel activated by receptor stimulation through a pathway that involves Ca2+ but not depletion of Ca2+ store in mammalian cells.
Paired immunoglobulin-like receptor B (PIR-B) (p91) molecule has been proposed to function as an inhibitory receptor in B cells and myeloid lineage cells. We demonstrate here that the cytoplasmic region of PIR-B is capable of inhibiting B cell activation. Mutational analysis of five cytoplasmic tyrosines indicate that tyrosine 771 in the motif VxYxxL plays the most crucial role in mediating the inhibitory signal. PIR-B-mediated inhibition was markedly reduced in the SH2-containing protein tyrosine phosphatases SHP-1 and SHP-2 double-deficient DT40 B cells, whereas this inhibition was unaffected in the inositol polyphosphate 5'-phosphatase SHIP-deficient cells. These data demonstrate that PIR-B can negatively regulate B cell receptor activation and that this PIR-B-mediated inhibition requires redundant functions of SHP-1 and SHP-2.
The effects of replacing Val49, Thr46, Asp96, and Phe219 in the cytoplasmic domain of bacteriorhodopsin on water O-H stretching vibrational bands and the amide I and imide II bands of the peptide backbone were examined in the M, N, and MN intermediates. This study is an extension of previous work on the L photointermediate [Yamazaki, Y., Tuzi, S., Saitô, H., Kandori, H., Needleman, R., Lanyi, J. K., and Maeda, A. (1996) Biochemistry 35, 4063-4068]. The O-H stretching bands at 3671 cm-1 in the M intermediate and at 3654 cm-1 in the N intermediate are shown to originate from the same water molecule. It is located in the region surrounded by the Schiff base, Val49, Thr46, and Phe219 in the M intermediate, and moves closer to Val49 in the M to N reaction. The peptide C-N bond between Val49 and Pro50 and the C=O bond of Val49 undergo perturbations upon formation of the N intermediate but not the M and N-like MN states in which the Schiff base is unprotonated. The carbonyl oxygen of Val49 is proposed to be the acceptor in H-bonding with the protonated Schiff base in the N intermediate. The results suggest that water molecules may be involved in this interaction in the cytoplasmic region, and may play a role in the accessibility change of the Schiff base in the L to M to N photocycle steps.