Central and peripheral mechanisms of narcotic antitussives: codeine-sensitive and -resistant coughs

Narcotic antitussives such as codeine reveal the antitussive effect primarily via the μ-opioid receptor in the central nervous system (CNS). The κ-opioid receptor also seems to contribute partly to the production of the antitussive effect of the drugs. There is controversy as to whether δ-receptors are involved in promoting an antitussive effect. Peripheral opioid receptors seem to have certain limited roles. Although narcotic antitussives are the most potent antitussives at present, certain types of coughs, such as chronic cough, are particularly difficult to suppress even with codeine. In guinea pigs, coughs elicited by mechanical stimulation of the bifurcation of the trachea were not able to be suppressed by codeine. In gupigs with sub-acute bronchitis caused by SO2 gas exposure, coughing is difficult to inhibit with centrally acting antitussives such as codeine. Some studies suggest that neurokinins are involved in the development of codeine-resistant coughs. However, evidence supporting this claim is still insufficient. It is very important to characterize opiate-resistant coughs in experimental animals, and to determine which experimentally induced coughs correspond to which types of cough in humans. In this review, we describe the mechanisms of antitussive effects of narcotic antitussives, addressing codeine-sensitive and -resistant coughs, and including our own results

MECHANICAL PROPERTIES OF ARTIFICIAL TEETH

In selecting the teeth for fabrication of complete or partial dentures, each patient s anatomic and physiologic requirements and the properties of the artificial teeth themselves should be taken into consideration. The purpose of this study was to evaluate the mechanical properties of the artificial teeth by the static compression test and the impact test. Specimens were the lower first molar porcelain and resin teeth (Livdent FB-20 teeth by G.C. Co., Tokyo, Japan). All were of the same shape. In the static compression test, the fracture load and deformation of the artificial teeth were measured with an Instron-type universal testing machine at a cross-head speed of 1.0 mm/min. Elastic modulus, ultimate strength and absorbed energy were calculated. In the impact test, the acceleration of a falling impactor was measured with a drop impact apparatus. The load applied to the specimen was equivalent to 300N. Absorbed energy and deformation were calculated.The resin teeth showed a lower elastic modulus, higher fracture toughness and shock-absorbing ability than the porcelain teeth. Resin teeth should be selected when the first requisite is high shock absorbing ability, and porcelain teeth should be selected when the first requisite is high masticating efficiency

Frequency, clinical characteristics, and outcomes of pneumonia in patients with out-of-hospital cardiac arrest undergoing extracorporeal cardiopulmonary resuscitation

Aim: This study aimed to describe the frequency, clinical characteristics, and outcomes of pneumonia in OHCA patients treated with ECPR in a multicenter setting. Methods: This is a secondary analysis of the SAVE-J II study, which was a multicenter, retrospective cohort of OHCA patients treated with ECPR. Age, sex, comorbidities, presence of witnessed CA, presence of bystander CPR, initial rhythm, cause of CA, low-flow time, initiation of targeted temperature management, details of sputum culture, pneumonia, and prophylactic antibiotic use were recorded. Pneumonia was diagnosed when the patients met all the clinical, radiologic, and microbiologic criteria acquired after hospitalization. Results: In total, 1,986 patients were included in the analysis, and 947 (48%) died during the first 2 days of admission. A prophylactic antibiotic was used in 712 (35.9%) patients. Overall, the hazard of death was high on days 1 and 2 of admission, exceeding 20% on both days; 251 (12.6%) patients developed pneumonia during hospitalization, and the hazard of pneumonia development remained high (>2%) in the first 7 days of admission.Staphylococcus aureus and Klebsiella species were commonly identified in the sputum culture. Among patients who survived the first 7 days, the odds ratio (OR) of those with pneumonia and unfavorable neurological outcomes defined by cerebral performance category 3–5 was approximately 1. In those who survived the first 10 days, the OR was greater than 1 with a wide confidence interval. Conclusions: This is the first study describing details of pneumonia in OHCA patients treated with ECPR using a large dataset

Risk factors for bleeding complications in patients undergoing extracorporeal cardiopulmonary resuscitation following out-of-hospital cardiac arrest: a secondary analysis of the SAVE-J II study

Abstract Background Bleeding is the most common complication in out-of-hospital cardiac arrest (OHCA) patients receiving extracorporeal cardiopulmonary resuscitation (ECPR). No studies comprehensively described the incidence rate, timing of onset, risk factors, and treatment of bleeding complications in OHCA patients receiving ECPR in a multicenter setting with a large database. This study aimed to analyze the risk factors of bleeding during the first day of admission and to comprehensively describe details of bleeding during hospitalization in patients with OHCA receiving ECPR in the SAVE-J II study database. Methods This study was a secondary analysis of the SAVE-J II study, which is a multicenter retrospective registry study from 36 participating institutions in Japan in 2013–2018. Adult OHCA patients who received ECPR were included. The primary outcome was the risk factor of bleeding complications during the first day of admission. The secondary outcomes were the details of bleeding complications and clinical outcomes. Results A total of 1,632 patients were included. Among these, 361 patients (22.1%) had bleeding complications during hospital stay, which most commonly occurred in cannulation sites (14.3%), followed by bleeding in the retroperitoneum (2.8%), gastrointestinal tract (2.2%), upper airway (1.2%), and mediastinum (1.1%). These bleeding complications developed within two days of admission, and 21.9% of patients required interventional radiology (IVR) or/and surgical interventions for hemostasis. The survival rate at discharge of the bleeding group was 27.4%, and the rate of favorable neurological outcome at discharge was 14.1%. Multivariable logistic regression analysis showed that the platelet count ( 10 × 104/μL) was significantly associated with bleeding complications during the first day of admission (adjusted odds ratio [OR]: 1.865 [1.252–2.777], p = 0.002). Conclusions In a large ECPR registry database in Japan, up to 22.1% of patients experienced bleeding complications requiring blood transfusion, IVR, or surgical intervention for hemostasis. The initial platelet count was a significant risk factor of early bleeding complications. It is necessary to lower the occurrence of bleeding complications from ECPR, and this study provided an additional standard value for future studies to improve its safety