Decrementing expiratory neurons of the Bötzinger complex

Summary In Nembutal-anesthetized, immobilized and artificially ventilated cats, decrementing expiratory (E-DEC) neurons which were excited by lung inflation were isolated in the vicinity of the Bötzinger complex. Then intracellular recordings were made from the respiratory neurons in the contralateral ventral respiratory group (VRG). The intracellular membrane potentials were averaged using extracellular spikes of the E-DEC neurons as triggers (spike-triggered averaging method). Hyperpolarizing potentials locked to the triggering spikes were obtained and they were shown to be unitary IPSPs since their polarity was reversed when averaged during passage of hyperpolarizing current. The latencies of antidromic activation of the E-DEC-neurons from the area of intracellular recordings were shorter by about 0.2 ms than those of unitary IPSPs. This showed that the connections were monosynaptic. A total of 47 pairs were analyzed and unitary IPSPs were found in 12 pairs. The E-DEC neurons inhibited both inspiratory and expiratory neurons, including bulbospinal inspiratory neurons, propriobulbar inspiratory neurons, and vagal motoneurons with expiratory activity. These inhibitory E-DEC neurons, receiving excitatory inputs from the stretch receptors of the lungs, presumably intervene in reflex loops such as the Hering-Breuer reflex and may make some contribution to normal breathing.Supported by grants-in-aid for science research nos. 60304044, 62570068 from the Japan Ministry of Education, Science and Culture     

Anaphylactic hepatic venoconstriction is attenuated by nitric oxide released via shear stress-dependent and -independent mechanisms in Guinea pig

1. The role of shear stress in nitric oxide (NO)-mediated attenuation of anaphylactic venoconstriction was studied using an isolated ovalbumin-sensitized guinea pig liver. 2. Guinea pigs were actively sensitized by a subcutaneous injection of 1 mg ovalbumin. Two weeks after sensitization, the livers were perfused with diluted blood under constant flow or constant perfusion pressure. The constant flow could result in increased shear stress during constriction, while the constant perfusion pressure could prevent changes in shear stress. Using the double occlusion technique to estimate the hepatic sinusoidal pressure, pre- and postsinusoidal constriction was evaluated. Hepatic anaphylaxis was induced by an injection of ovalbumin (4 microg) into the perfusate, the volume of which was 40 mL. 3. Under either constant flow or pressure, anaphylaxis caused venoconstriction of predominantly presinusoids over postsinusoids, although anaphylactic venoconstriction under constant pressure was significantly greater than that under constant flow. When shear stress was held constant by maintaining constant perfusion pressure, a NO synthase inhibitor, Nomega-nitro-L-arginine methyl ester (L-NAME, 100 micromol/L), potentiated similarly both pre- and postsinusoidal constriction induced by anaphylaxis. This suggests that hepatic anaphylaxis shear stress-independently generates NO, resulting in dilatation of both pre- and postsinusoidal vessels in a similar magnitude. In contrast, when shear stress was allowed to rise under constant flow, anaphylactic presinusoidal constriction was preferentially potentiated by L-NAME. 4. Hepatic anaphylaxis can increase NO production in a shear stress-independent manner and dilates similarly both pre- and postsinusoids, while NO produced in a shear stress-dependent manner attenuates predominantly venoconstriction of the presinusoids where shear stress is preferentially increased.     

Influence of 320-detector-row volume scanning and AAPM report 111 CT dosimetry metrics on size-specific dose estimate: a Monte Carlo study

The American Association of Physicists in Medicine (AAPM) task group 204 has recommended the use of size-dependent conversion factors to calculate size-specific dose estimate (SSDE) values from volume computed tomography dose index (CTDI_vol) values. However, these conversion factors do not consider the effects of 320-detector-row volume computed tomography (CT) examinations or the new CT dosimetry metrics proposed by AAPM task group 111. This study aims to investigate the influence of these examinations and metrics on the conversion factors reported by AAPM task group 204, using Monte Carlo simulations. Simulations were performed modelling a Toshiba Aquilion ONE CT scanner, in order to compute dose values in water for cylindrical phantoms with 8–40-cm diameters at 2-cm intervals for each scanning parameter (tube voltage, bow-tie filter, longitudinal beam width). Then, the conversion factors were obtained by applying exponential regression analysis between the dose values for a given phantom diameter and the phantom diameter combined with various scanning parameters. The conversion factors for each scanning method (helical, axial, or volume scanning) and CT dosimetry method (i.e., the CTDI₁₀₀ method or the AAPM task group 111 method) were in agreement with those reported by AAPM task group 204, within a percentage error of 14.2 % for phantom diameters ≥11.2 cm. The results obtained in this study indicate that the conversion factors previously presented by AAPM task group 204 can be used to provide appropriate SSDE values for 320-detector-row volume CT examinations and the CT dosimetry metrics proposed by the AAPM task group 111.     

OF4949, new inhibitors of aminopeptidase B. II. Elucidation of structure

The structures of OF4949-I, II, III and IV were identified by analysis of the products of their chemical degradation and by 1H NMR, 13C NMR, and mass spectrometry. These compounds were new cyclic peptides containing diphenyl ether as a chromophore. OF4949-I had two amino acids, beta-hydroxy-L-asparagine and 4-methylisodityrosine. The structural differences between I and II and between III and IV lay solely in the diphenyl ether moiety; the phenolic hydroxyl group in II and IV was methylated in I and III. OF4949-III and IV contained L-asparagine instead of the beta-hydroxy-L-asparagine moiety of I and II.     

Annuloplasty ring removal from patients with hemolysis after mitral valve repair

We present a case of severe hemolysis following a mitral valve repair, which was successfully treated by removing the annuloplasty ring. The etiology of the hemolysis appeared to be a small regurgitant jet at the level of the annuloplasty ring.     

The role of serum interleukin-8 in hepatic resections

Purpose

Interleukin-8 (IL-8) is a neutrophil chemotactic factor, which is associated with some inflammatory diseases and various types of surgical stress. The aim of this study was to investigate whether the early postoperative serum IL-8 level may potentially be a new indicator of a surgical stress in patients undergoing a hepatic resection.

Methods

The serum IL-8 levels were measured in 37 patients who underwent a hepatectomy. The serum IL-8 levels were serially measured using an enzyme-linked immunosorbent assay both before and after a hepatic resection. In addition, the correlation between the postoperative IL-8 value and several clinical variables were examined.

Results

The mean level of IL-8 significantly increased immediately after the operation (P < 0.01 vs before the operation) and decreased on the first postoperative day (POD 1, P < 0.05 vs after the operation). The early postoperative IL-8 levels positively correlated with the length of the procedure (r = 0.383; P < 0.05), the estimated blood loss (r = 0.483; P < 0.01) and the serum bilirubin level on POD 1 (r = 0.390; P < 0.05), and inversely correlated with the white blood cell counts (r = ?0.388; P < 0.05) and lymphocyte counts on POD 1 (r = ?0.424; P < 0.05). In a comparison of the postoperative IL-8 levels with the surgical factors, there was a significant difference in the extension of the resection (P < 0.05) and in blood transfusion. The patients with a fever of more than 38°C showed higher levels of IL-8 immediately after the operation than those without fever (P < 0.01).

Conclusions

The early postoperative serum IL-8 level was found to correlate with the degree of the severity of surgery in patients undergoing a hepatic resection, and it is also considered to be a new indicator of surgical stress and liver injury.     

Edge-to-edge mitral valve repair for anterior leaflet prolapse associated with extensive calcification of the mitral annulus: Report of a case

Extensive mitral annular calcification remains a technical challenge in mitral valve surgery. Decalcification and reconstruction of the mitral annulus is an established technique, but it is time consuming and technically demanding. This report presents the case of an 88-year-old diabetic female patient in whom edge-toedge repair was completed quickly, with good early results thus being obtained.     

Both Fibrous Capsule Formation and Extracapsular Penetration Are Powerful Predictors of Poor Survival in Human Hepatocellular Carcinoma: A Histological Assessment of 365 Patients in Japan

Background  A new definition of infiltration to the capsule (fc-inf) has been proposed as a novel marker for predicting the prognosis of 88 patients with hepatocellular carcinoma (HCC). The current aim was to present evidence to develop the fibrous capsule and fc-inf, from the Japanese histological findings for HCC, and to validate their biological significances and predictive power of survival in a large series. Methods  A total of 365 HCCs were divided into HCCs without the fibrous capsule (NC type; n = 135) and HCCs with the fibrous capsule (FC type; n = 230). Then, FC type was subclassified into two types: extracapsular infiltrating (EC) type (n = 125), in which cancer cells penetrated outside the fibrous capsule, and intracapsular (IC) type (n = 105), in which the infiltrating cancer cells stayed inside the fibrous capsule. Results  The proportion of less histological differentiation and portal venous invasion was higher in FC type than in NC type. The fibrous capsule came to be observed according to the increase of tumor size (P < 0.0001). FC type had significantly poorer outcome for overall survival than NC type (P = 0.0022). EC type showed more intrahepatic metastasis than IC type. The macroscopic subclassifications were significantly affected the presence of fc-inf. EC type had significantly poorer outcome for disease-free survival than IC type (P = 0.0132) and was an independent prognostic factor for disease-free survival (P = 0.0482). Conclusions  Fc-inf defined as extracapsular penetration was verified to be a novel marker for predicting prognosis, and presence of fc-inf might be predicted by tumor gross features.