Potentiation by sevoflurane of the gamma-aminobutyric acid-induced chloride current in acutely dissociated CA1 pyramidal neurones from rat hippocampus.

1. The effects of a new kind of volatile anaesthetic, sevoflurane (Sev), on gamma-aminobutyric acid (GABA)-gated chloride current (Icl) in single neurones dissociated from the rat hippocampal CA1 area were examined using the nystatin perforated patch recording configuration under the voltage-clamp condition. All drugs were applied with a rapid perfusion system, termed the "Y-tube' method. 2. When the concentrations were higher than 3 x 10(-4) M, Sev, itself, induced an inward current (ISev) at a holding potential (VH) of -40 mV. The concentration-response curve of ISev was bell-shaped, with a suppressed peak and plateau currents at high concentrations (above 2 x 10(-3) M). The reversal potential of ISev (ESev) was close to the theoretical Cl- equilibrium potential, indicating that ISev was carried mainly by Cl-. 3. ISev was reversibly blocked by bicuculline (Bic), an antagonist of the GABAA receptor, in a concentration-dependent manner with a half-inhibitory concentration (IC50) of 7.2 x 10(-7) M. But ISev was insensitive to strychnine (Str), an antagonist of the glycine receptor. 4. At low concentrations (between 3 x 10(-4) and 10(-3) M), Sev markedly enhanced the 10(-6) M GABA induced current (IGABA) but reduced the IGABA with accelerating desensitization accompanied by a "hump' current after washout at high concentrations (higher than 2 x 10(-3) M). 5. Sev, 10(-3) M potentiated the current induced by low concentrations of GABA (between 10(-7) and 3 x 10(-6) M) but reduced the current induced by high concentrations (higher than 10(-5) M) of GABA with a clear acceleration of IGABA desensitization. 6. Sev, like pentobarbitone (PB), pregnanolone (PGN) or diazepam (DZP), potentiated the 10(-6) M GABA-induced response without shifting the reversal potential of IGABA. 7. ISev was augmented by PB, PGN, or DZP at concentrations that maximally potentiated IGABA, suggesting that Sev enhanced IGABA at a binding site distinct from that for PB, PGN, or DZP. 8. It is concluded that Sev acts on the GABAA receptor complex mimicking the GABA-induced chloride current at high concentrations. At low concentrations, Sev enhances GABA-gated chloride current at a binding site independent of the allosteric modulator sites of barbiturates, benzodiazepines or neurosteroids. The reversible potentiation of the inhibitory GABAA receptor-mediated Cl- current may result in the depressing of postsynaptic excitability and may, at least in part, underlie the anaesthetic action of Sev.     

Detection of respiratory syncytial virus with nested RT-PCR and a new rapid detection test kit in patients with influenza-like illness, including elderly adults

Respiratory syncytial virus (RSV) infection, a common lower respiratory infection in infants, is now recognized in the USA as a significant problem in elderly adults. RSV infection has rarely been reported in adults in Japan. Nasal samples from 77 patients with influenza-like illness (ILI) and negative for influenza in a rapid antigen detection kit were also tested by polymerase chain reaction (PCR) to identify RSV. A clinical trial was also conducted using a new antigen detection test kit for RSV based on immunochromatography. RSV was detected by nested RT-PCR in samples from nasal swabs of 10 patients--3 children and 5 adults--and nasal aspiration samples in 2 children. The frequency of RSV detection by nested RT-PCR in ILI patients with a negative response for influenza virus using the rapid detection kit was 27.3% (3/11) for children aged 0 to 1 year and 33.3% (2/6) for children aged 2-3 years. The frequency was 10% (1/10) for adults aged 30-39 years, 25% (1/4) for those aged 70-79 years, and 60% (3/5) for those aged 80-89 years. By month, the frequency was 25% (2/8) for December, 27.3% (6/22) for January, and 4.4% (2/45) for February. The main clinical symptoms of the 10 patients with RSV were: peak body temperature during the clinical course of 37.2-39.7 degrees C, cough, and rhinorrhea in 9. Stridor was observed in all five children, but not in the five adults. Clinical examination showed CRP to be 0.2-3.4 (mean 1.3) mg/dL and WBC to be 3070-8000 (mean 5584) /microL for nine patients. Lymphocytopenia was observed in the four adults from whom WBC fraction data was obtained. Chest X-ray was within normal limits. RSV was detected by the new rapid antigen detection kit in 9 of the 10 patients in whom RSV was detected by PCR, but not in any of the 67 patients in whom RSV was not detected. The diagnostic accuracy of the new antigen detection kit for RSV was thus excellent at 98.7% compared to PCR. RSV was detected from nasal swab specimens of a substantial number of elderly Japanese by PCR or the antigen detection kit.     

Establishment of local diagnostic reference levels for quality control in intraoral radiography

Objective

To investigate the dosage and imaging conditions for patients undergoing intraoral radiography at Meikai University Hospital and establish assurance and quality control data.

Methods

Tube voltage, exposure time, and air kinetic energy released per unit mass (air kerma) of three intraoral radiography units were measured. To calculate the patient entrance dose (PED) for each radiograph using Insight film, we extracted data for 1063 patients from their exposure records. The PED was compared with the diagnostic reference level (DRL) from the European Commission and the UK.

Results

The tube voltage of the three units was maintained at 60 ± 2 kV. Differences in exposure time were less than 1.7 % for all units. The air kerma rates were well maintained within a 4.2 % error. Based on the patient data, there were no significant differences in the mean exposure times for males and females for all anatomical sites. The mean PED ranged from 1.09 ± 0.31 mGy for the mandibular incisors to 2.42 ± 0.33 mGy for the maxillary molars. The mean PED at the mandibular molars using InSight film was 1.59 ± 0.20 mGy, being less than the recommended value based on the DRL for intraoral radiography in the UK.

Conclusions

We concluded that radiographic conditions at the hospital have been properly maintained. This basic quality control data may assist other dental radiation facilities to reduce patient dosage.

     

Duration of fever and other symptoms after the inhalation of laninamivir octanoate hydrate in the 2016/17 Japanese influenza season; comparison with the 2011/12 to 2015/16 seasons

The duration of fever and symptoms after laninamivir octanoate hydrate (laninamivir) inhalation were investigated in the Japanese 2016/17 influenza season and the results were compared with those of the 2011/12 to 2015/16 seasons. A total of 1278 patients were evaluated for the duration of fever and symptoms in the six studied seasons. In the 2016/17 season, the influenza types/subtypes of the patients were 6 A (H1N1)pdm09 (2.9%), 183 A (H3N2) (87.6%), and 20 B (9.6%). The respective median durations of fever for A (H1N1)pdm09, A (H3N2), and B were 38.0, 33.0, and 38.5 h, without significant difference (p = 0.9201), and the median durations of symptoms were 86.5, 73.0, and 99.0 h, with significant difference (p = 0.0342).The median durations of fever and symptoms after laninamivir inhalation were quite consistent for the six studied seasons for A (H1N1)pdm09, A (H3N2), and B, without any significant differences. The percentage of patients with unresolved fever patients displayed a similar pattern through the six studied seasons for all these virus types.There was no significant difference in the duration of fever or symptoms between the Victoria and Yamagata lineages in the 2016/17 season and those of the previous studied seasons. Over the seasons tested, ten adverse drug reactions (ADRs) were reported from 1341 patients. The most frequent ADR was diarrhea and all ADRs were self-resolving and not serious. These results indicate the continuing clinical effectiveness of laninamivir against influenza A (H1N1)pdm09, A (H3N2), and B, with no safety issues.     

Evaluation of an immunochromatography test kit for rapid diagnosis of influenza

We assessed the sensitivity and specificity of the Capilia Flu AB rapid diagnosis kit for influenza that utilizes the immunochromatography method. Tested were 114 influenza like illness patients in the 2001/2002 influenza season. We used Capilia Flu AB and Infu A . B Quick, a rapid diagnosis kit based on enzyme immunoassay. As laboratory confirmation tests, influenza virus isolation and polymerase chain reaction (PCR) were done. Those patients with positive results from virus isolation or PCR were regarded as influenza patients. The sensitivities of nasal swab, pharyngeal swab, and nasal wash specimens were 82.8%, 80.0%, and 75.0%, respectively. The specificities of nasal swab, pharyngeal swab, and nasal wash specimens were 95.3%, 93.9%, and 100%, respectively. A total of 20 patients displayed different results in comparison of their nasal and pharyngeal swabs: 15 patients were positive with the nasal swab but negative with the pharyngeal swab and 5 patients were negative with the nasal swab but positive with the pharyngeal swab. Nasal swab would seem to be preferable in terms of sensitivity. The sensitivity and specificity of Capilia Flu AB were a little higher than those of Influ A . B Quick, but with no significant difference. The one-step operation of Capilia Flu AB is easier than the four steps required by Influ A . B Quick, but the time required to make a diagnosis is the same. No significant age related difference in the effectiveness of the kits was found. The Capilia Flu AB rapid diagnosis kit is useful in clinical practice because it has good sensitivity (about 80%) and specificity (about 90%), and it is easy to use.     

Reduction of liver stiffness by interferon treatment in the patients with chronic hepatitis C

Aim: To assess the regression of liver fibrosis after interferon (IFN) treatment in patients with chronic hepatitis C, liver stiffness (LS) was measured repeatedly and the factors associated with reduction of LS were assessed. Methods: LS was measured by transient elastography before treatment, at end of treatment (EOT), and 1 year and 2 years after EOT in 145 patients with chronic hepatitis C treated by IFN with or without ribavirin. Results: In the patients with sustained virological response (SVR) (n = 93) and relapsers (n = 28), LS significantly decreased at EOT (median, 5.4 [interquartile range, 4.0–8.6] kilopascals [kPa], P < 0.0001 and 6.8 [4.5–8.9] kPa, P = 0.0023) and 1 year after EOT (5.3 [4.2–7.0] kPa, P < 0.0001 and 6.8 [4.5–9.3] kPa, P = 0.0204) compared with baseline (8.0 [5.0–11.9] kPa and 10.6 [7.0–16.6] kPa). In SVR patients, LS significantly decreased 2 years after EOT (5.3 [4.1–6.3] kPa) compared with baseline (P < 0.0001) and LS at EOT (P = 0.0034). Two points or greater reduction of deduced stage at last LS measurement was observed in 78% of SVR patients, 59% of relapsers and 15% of patients with non‐virological response whose pretreatment deduced stages were F3–F4. Fibrosis stage, hyaluronic acid levels, duration of treatment, response to treatment and alanine aminotransferase levels were associated with a 2‐point or greater decrease of deduced fibrosis stage. Conclusion: IFN treatment reduced LS in SVR patients and relapsers. Significant reduction of LS is associated with milder fibrosis stage, lower hyaluronic acid levels, longer IFN treatment, virological response of SVR or relapse and higher alanine aminotransferase levels.     

Excitatory amino acid responses in relay neurons of the rat lateral geniculate nucleus

Responses to glutamate receptor agonists were recorded from identified relay neurons in the dorsal lateral geniculate nucleus of the rat, using the nystatin-perforated patch-clamp technique. Rapid application of glutamate, N-methyl-D-aspartate, (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and kainate induced inward currents at a holding potential of -44 mV. The responses to low concentrations of each agonist were composed only of steady-state currents, but the responses to high concentrations were additionally composed of a rapid transient peak component except in the kainate-induced current. The currents induced by 10(-3)M N-methyl-D-aspartate in the external solution containing 0 mM Mg2+ and 10(-6)M glycine were reduced in amplitude when the external solution contained 1 mM Mg2+, and were abolished when the solution contained no glycine. The currents induced by a neurotransmitter candidate at retinogeniculate synapses, N-acetyl-aspartyl-glutamate, were markedly reduced in amplitude when the solution contained 1 mM Mg2+ or 10(-4)M DL-2-amino-5-phosphonovaleric acid. The current abolished in the Mg2+-containing, glycine-free solution (N-methyl-D-aspartate component) and the current remaining in the same solution (non-N-methyl-D-aspartate component) of the N-acetyl-aspartyl-glutamate response were both increased in a concentration-dependent manner, as the N-acetyl-aspartyl-glutamate concentration was increased. The current-voltage relationship of the currents induced by N-methyl-D-aspartate and N-acetyl-aspartyl-glutamate was characterized by Mg2+-dependent block at hyperpolarized potentials. The inward currents induced by 3 x 10(-4)M AMPA and 3 x 10(-4)M glutamate were markedly potentiated by 10(-4)M cyclothiazide, but the currents induced by 3 x 10(-4)M kainate and 10(-3)M N-acetyl-aspartyl-glutamate (non-N-methyl-D-aspartate component) were little affected. The currents induced by any agonist were not affected by 3 x 10(-4)g/ml concanavalin A. The current induced by 10(-4)M kainate was markedly suppressed by pretreatment with 10(-4)M AMPA or 10(-4)M glutamate, but only weakly by 10(-3)M N-acetyl-aspartylglutamate. The Ca2+ permeability (PCa/PCs) of the N-methyl-D-aspartate and non-N-methyl-D-aspartate receptors was 9.57 and 0.16, respectively. These results suggest that dorsal lateral geniculate nucleus relay neurons of the rat possessed both Ca2+-permeable N-methyl-D-aspartate receptors and less permeable non-N-methyl-D-aspartate (presumably AMPA) receptors, and that N-acetyl-aspartyl-glutamate mainly acts at N-methyl-D-aspartate receptors with a weak kainate-like action on non-N-methyl-D-aspartate receptors.     

Drug sensitivity test of Campylobacter jejuni strains isolated from human diarrheal stools, chicken meat, and chicken feces, and gene mutation of quinolone-resistant strains

In basic studies on campylobacteriosis, we tested 53 strains from human diarrhea stools and 102 strains from chicken meat and feces obtained between 2002 and 2006 for drug sensitivity to different drugs and gene mutation in quinolone-resistant strains. 1) Of 15 drugs tested, all were resistant to one or more of the following 10 drugs: CEX, 99.4%: ABPC, 59.4%; NA, 40.6%; NFLX, 40.0%; TC and CPFX, 39.4%; PIPC, 38.1%; MINO, 30.3%; KM, 3.2%; and SM, 2.6%. 2) Of 155 drug-resistant strains, 28 (18.1%) were resistant to single drugs and 127 (81.9%) were resistant to multiple drugs. The most frequent pattern of multipledrug resistance was ABPC/PIPC/CEX, followed by ABPC/PIPC/CEX/TC/MINO/NA/NFLX/CPFX. 3) Mutation of GyrA (Thr86 --> Ile) was detected in 43 (97.7%) of 44 quinolone-resistant strains. We found that resistance to beta-lactams, quinolones, and tetracycline antibiotics was high, and most resistant strains were resistant to multiple drugs. We also found that most quinolone-resistant strains had GyrA mutation.