Impact of acute hypoxia on heart rate and blood pressure variability in conscious dogs

To examine whether the impacts of hypoxia on autonomic regulations involve the phasic modulations as well as tonic controls of cardiovascular variables, heart rate, blood pressure, and their variability during isocapnic progressive hypoxia were analyzed in trained conscious dogs prepared with a permanent tracheostomy and an implanted blood pressure telemetry unit. Data were obtained at baseline and when minute ventilation (VI) first reached 10 (VI10), 15 (VI15), and 20 (VI20) l/min during hypoxia. Time-dependent changes in the amplitudes of the high-frequency component of the R-R interval (RRIHF) and the low-frequency component of mean arterial pressure (MAPLF) were analyzed by complex demodulation. In a total of 47 progressive hypoxic runs in three dogs, RRIHF decreased at VI15 and VI20 and MAPLF increased at VI10 and VI15 but not at VI20, whereas heart rate and arterial pressure increased progressively with advancing hypoxia. We conclude that the autonomic responses to isocapnic progressive hypoxia involve tonic controls and phasic modulations of cardiovascular variables; the latter may be characterized by a progressive reduction in respiratory vagal modulation of heart rate and a transient augmentation in low-frequency sympathetic modulation of blood pressure.     

ERp57 binds competitively to protein disulfide isomerase and calreticulin

In this study, we screened for protein disulfide isomerase (PDI)-binding proteins in bovine liver microsomes under strict salt concentrations, using affinity column chromatography. One main band observed using SDS-PAGE was identified as ERp57 (one of the PDI family proteins) by LC-MS/MS analysis. The K(D) value of PDI binding to ERp57 was calculated as 5.46x10(-6)M with the BIACORE system. The interactions between PDI and ERp57 occurred specifically at their a and b domains, respectively. Interestingly, low concentrations of ERp57 enhanced the chaperone activity of PDI, while high concentrations interfered with chaperone activity. On the other hand, ERp57 did not affect the isomerase activity of PDI. Additionally, following pre-incubation of ERp57 with calreticulin (CRT), decreased interactions were observed between ERp57 and PDI, and vice versa. Based on the data, we propose that once ERp57 binds to PDI or CRT, the resultant complex inhibits further interactions. Therefore, ERp57 selectively forms a protein-folding complex with PDI or CRT in ER.     

Different antibody- and cytokine-mediated responses to Plasmodium falciparum parasite in two sympatric ethnic tribes living in Mali

The Fulani are known to be less susceptible to Plasmodium falciparum malaria infections and to have lower parasitaemia despite living under similar malaria transmission intensity compared with other ethnic tribes. The aim of the present study was to examine whether the Fulani were more polarised towards Th2 as reflected by higher numbers of malaria-specific IL-4- and IL-10-producing cells and lower numbers of IFN-gamma- and IL-12-producing cells as compared to their neighbour ethnic tribe, the Dogon of Mali. Total IgE and both anti-malaria IgE and IgG antibodies were measured by ELISA and the numbers of IL-4-, IFN-gamma-, IL-10- and IL-12-producing cells were enumerated using enzyme-linked ImmunoSpot assay (ELISPOT). Numbers of parasite clones were detected by polymerase chain reaction (PCR). The study was performed outside the transmission period and all individuals included were asymptomatic. The results revealed that the Fulani were less parasitised, had fewer circulating parasite clones in their blood, had significantly higher anti-malaria IgG and IgE antibodies and higher proportions of malaria-specific IL-4- and IFN-gamma-producing cells compared to the Dogon. The higher antigen-specific production of IL-4 among the Fulani was statistically significant both before and after adjustment for level of spontaneous cytokine production, while greater IFN-gamma production only attained statistical significance after adjustment for spontaneous levels. Taken together, the association of higher anti-malarial IgE and IgG antibodies and increased numbers of specific IL-4- and IFN-gamma-producing cells compared to the ethnic sympatric tribe, the Dogon, may assist in explaining the lower susceptibility to malaria observed in the Fulani.     

Properties and application to immunoassay of monoclonal antibodies to neuron-specific γγ enolase

Two monoclonal antibodies to human and bovine neuron-specific γγ enolase have been produced in the isolated hybrid cell lines, which were obtained by fusion between γγ-immunized mouse spleen cells and mouse myeloma cells (P3-NS-1/1-Ag4-1), followed by a screening procedure with an enzyme immunoassay. The monoclonal antibody to human γγ enolase (E1-G3) and that to bovine γγ enolase (B1-D6) consisted of γ2a/κ and γl/κ immunoglobulin chains, respectively. Both antibodies could bind with the respective antigen with a molar ratio of about 1:1, and were found to be specific for the γ subunit of enolase, showing reactivities with human γγ and αγ, rat γγ and αγ, and bovine γγ enolases. However, the antibodies did not cross-react with the α or β subunit of human and rat enolase isozymes. Both antibodies could partially inhibit the activity of γγ and αγ enolases. E1-G3 antibody inhibited γγ and αγ enolase activity by 70 and 30%, respectively, and B1-D6 antibody, by 90 and 40%, respectively. Both antibodies had no effect on the activity of αα and ββ enolases of human and rat origins. The applicability of E1-G3 and B1-D6 antibodies to the sandwich-type enzyme immunoassay for neuron-specific enolase (enolase γ subunit) was examined, and it was found that the assay system using E1-G3 and B1-D6 as the labeled antibodies were sufficiently sensitive for the assay of serum neuron-specific enolase concentrations.     

Orientation of Microtubules during Regeneration of Cell Wall in Selected Giant Marine Algae

The microtubules in highly synchronized aplanospores of twogiant marine algae, Boergesenia forbesii and Valonia ventricosa,were examined by immunofluorescence microscopy throughout theregeneration of the cell wall. Microtubule orientation was alwaysrandom up to 20 h after wounding, although the orientation ofcellulose microfibrils changed from random to parallel withinthat time period. When the rhizoid cells were in the stage ofelongation at 7 to 10 days after wounding, highly ordered microtubuleswere always observed along the longitudinal cell axis exceptat the very tip of the cells where random ones were found. Incontrast, the microfibrils in the innermost lamellae of newlysynthesized cell walls showed three different orientations,that is, transverse, longitudinal and oblique to the longitudinalcell axis. These observations suggest that microtubules maycontrol cell shape, but not the orientation of microfibrils.The mechanism of cell wall construction in these algae is discussedin relation to the self-assembly mechanism thought to operatein the construction of helicoidal cell walls. ³ Present address: Polymer Research Laboratory, Mitsui ToatsuChemicals, Inc., Yokohama, Kanagawa 244, Japan. (Received November 18, 1987; Accepted April 11, 1988)     

Minimal Internal Radiation Exposure in Residents Living South of the Fukushima Daiichi Nuclear Power Plant Disaster

Following the Fukushima nuclear power plant disaster, assessment of internal radiation exposure was indispensable to predict radiation-related health threats to residents of neighboring areas. Although many evaluations of internal radiation in residents living north and west of the crippled Fukushima nuclear power plant are available, there is little information on residents living in areas south of the plant, which were similarly affected by radio-contamination from the disaster. To assess the internal radio-contamination in residents living in affected areas to the south of the plant or who were evacuated into Iwaki city, a whole body counter (WBC) screening program of internal radio-contamination was performed on visitors to the Jyoban hospital in Iwaki city, which experienced less contamination than southern areas adjacent to the nuclear plant. The study included 9,206 volunteer subjects, of whom 6,446 were schoolchildren aged 4–15 years. Measurements began one year after the incident and were carried out over the course of two years. Early in the screening period only two schoolchildren showed Cs-137 levels that were over the detection limit (250 Bq/body), although their Cs-134 levels were below the detection limit (220 Bq/body). Among the 2,760 adults tested, 35 (1.3%) had detectable internal radio-contamination, but only for Cs-137 (range: 250 Bq/body to 859 Bq/body), and not Cs-134. Of these 35 subjects, nearly all (34/35) showed elevated Cs-137 levels only during the first year of the screening. With the exception of potassium 40, no other radionuclides were detected during the screening period. The maximum annual effective dose calculated from the detected Cs-137 levels was 0.029 and 0.028 mSv/year for the schoolchildren and adults, respectively, which is far below the 1 mSv/year limit set by the government of Japan. Although the data for radiation exposure during the most critical first year after the incident are unavailable due to a lack of systemic measurements, the present results suggest that internal radio-contamination levels more than one year after the incident were minimal for residents living south of the crippled Fukushima nuclear plant, and that the annual additional effective doses derived from internal Cs contamination were negligible. Thus, internal radio-contamination of residents living in southern radio-contaminated areas appears to be generally well controlled.     

Heart Rate Variability Biofeedback Improves Cardiorespiratory Resting Function During Sleep

The present study was designed to examine the effect of heart rate variability (HRV) biofeedback on the cardiorespiratory resting function during sleep in daily life. Forty-five healthy young adults were randomly assigned to one of three groups: HRV biofeedback, Autogenic Training (AT), and no-treatment control. Participants in the HRV biofeedback were instructed to use a handheld HRV biofeedback device before their habitual bedtime, those in the AT were asked to listen to an audiotaped instruction before bedtime, and those in the control were asked to engage in their habitual activity before bedtime. Pulse wave signal during sleep at their own residences was measured continuously with a wristwatch-type transdermal photoelectric sensor for three time points. Baseline data were collected on the first night of measurements, followed by two successive nights for HRV biofeedback, AT, or control. Cardiorespiratory resting function was assessed quantitatively as the amplitude of high-frequency (HF) component of pulse rate variability, a surrogate measure of respiratory sinus arrhythmia. HF component increased during sleep in the HRV biofeedback group, although it remained unchanged in the AT and control groups. These results suggest that HRV biofeedback before sleep may improve cardiorespiratory resting function during sleep.     

Forensic species identification of large macaws using DNA barcodes and microsatellite profiles

Using mitochondrial and nuclear markers species identification was conducted in the case of seized feathers. Earlier, we had sequenced cytochrome c oxidase subunit I (COI) both from 10 seized specimens and 43 validation specimens from captive macaws belonging to 4 Ara species (A. macao, A. chloropterus, A. ararauna, and A. ambiguus) and identified 19 haplotypes based on COI sequences. Species-level identification using Barcode of Life Data Systems showed that seized feathers shared the highest similarity with scarlet macaws (A. macao), and this result was supported by the tree-base identification with high bootstrap values. Moreover, microsatellite profiles in AgGT17 locus showed that patterns of allelic distribution in the seized feathers were apparently distinct from those of red-and-green macaw (A. chloropterus), but were overlapped with those of A. macao, suggesting that all of seized feathers were derived from several individuals of A. macao. We also determined the parentage of hybrid macaws by the combination of COI barcodes and microsatellite profiles. The technique presented here will contribute to forensic identification and future conservation of large macaws that have been lost due to deforestation.     

Remarkable consistency of exon-intron structure of hatching enzyme genes and molecular phylogenetic relationships of teleostean fishes

The phylogenetic positions of various fishes in the Teleostei are frequently confused. One such confusion is in the phylogenetic relationships among Salmoniformes, Esociformes, Osmeriformes, Argentiniformes and Alepocephaliformes. While morphology-based phylogenetic studies suggested that all of these belong to Euteleostei, molecule-based phylogenetic analyses indicated that the former four orders belong to the Euteleostei, and the Alepocephaliformes to the Otocephala. In addition, the phylogenetic relationships among the former four orders have not been established: morphological studies have proposed various hypotheses, while molecular analyses have suggested esociforms and salmoniforms to be sister groups at the basal position in euteleosts. In this study, we examined their controversial phylogenetic positions using exon-intron structures of hatching enzyme genes. The gene structures of alepocephaliforms were characteristic to those of lower otocephalans. Those of argentiniforms and osmeriforms were the same as those of higher euteleosts, but different from those of salmoniforms and esociforms. The results suggest that alepocephaliforms are closely related to otocephalans, and salmoniforms form a sister group to esociforms in euteleosts. Therefore, changes in exon-intron structure of hatching enzyme genes correspond well with the molecular phylogenetic relationship estimated from mitochondrial DNA sequences.