Preclinical evaluation of a hollow fiber silicone membrane oxygenator for extracorporeal membrane oxygenator application

A silicone membrane hollow fiber oxygenator applicable for use as an extracorporeal membrane oxygenator (ECMO) has been developed in our laboratory. This silicone hollow fiber displays astonishing mechanical stability, is barely compressible or stretchable, and assembles easily while maintaining good gas permeability. The priming volume is 140 cc with a surface area of 0.8 m2. This study evaluated the gas transfer performances and biocompatibility of the oxygenator under ECMO and CPB conditions. In vitro studies that were performed at a blood flow rate of 2 L/min, and revealed O2 and CO2 gas transfer rates of 82.35 +/- 0.56 ml/m2/L/min and 38.72 +/- 2.88 ml/m2/L/min, respectively. The commercially available Kolobow (Avecor 1500) oxygenator was used as the control, and had O2 and CO2 gas transfer rates of 53.8 +/- 0.5 ml/m2/L/min and 24.7 +/- 2.0 ml/m2/L/min. To evaluate blood trauma, Normalized Index of Hemolysis (NIH) was measured according to American Society of Testing and Materials (ASTM) standards. The NIH findings were 0.0112 g/100L at a blood flow of 1 L/min, and 0.0152 g/100L at 5 L/min. Three ex vivo experiments, using a blood flow rate of 1 L/min, were performed with venoarterial bypass, and O2 transfer rate and CO2 transfer rate of the oxygenators were well maintained. This indicates that this preclinical silicone membrane hollow fiber oxygenator has superior efficiency, less blood trauma, and is smaller when compared with the only clinically available Kolobow oxygenator.     

Polyethylene/phospholipid polymer alloy as an alternative to poly(vinylchloride)-based materials

To develop new biomaterials for making medical devices, polymer alloys composed of a phospholipid polymer, poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), and polyethylene (PE) were prepared. The PE/PMPC alloy membrane could be obtained by a combination of solution mixing and solvent evaporation methods using xylene and n-butanol mixture as a solvent. Moreover, thermal treatment was applied to improve the mechanical properties of the PE/PMPC alloy membrane. In the PE/PMPC alloy membrane, the PMPC domains were located not only inside the membrane but also at the surface. Surface analysis of the PE/PMPC alloy membrane with X-ray photoelectron spectroscopy, wettability evaluation, and dynamic contact angle measurements revealed that the phospholipid polar groups in the PMPC covered the surface even after thermal treatment. Blood compatibility tests with attention to platelet adhesion and change in morphology of adhered platelets showed that the PE/PMPC alloy membrane had excellent platelet adhesion resistance. We finally concluded that the PE/PMPC alloy could be used as biomaterials instead of poly(vinyl chloride)-based materials.     

Dependence of the anterior olfactory area self-stimulation upon the lateral hypothalamic area

The functional relation between the anterior olfactory area (AO) and the lateral hypothalamic area (LH) was examined in a self-stimulation situation. Bar-pressing responses for AO sitmulation were suppressed by unilateral injection of procaine, and enhanced by glutamate, into LH. Neither procaine nor glutamate injected into AO had any influence upon LH self-stimulation. It is unlikely that the procaine effect was due to motor disturbance because similar injection of procaine into LH did not disturb the performance of a one-way avoidance task. It appears that the rewarding effect of AO stimulation is dependent upon the excitation of the more caudal structures including LH.     

INFANTILE DIGITAL FIBROMATOSIS HISTOPATHOLOGICAL and ELECTRON MICROSCOPIC STUDY WITH A REVIEW OF THE LITERATURE

Five cases of Infantile digital fibromatosis were described. Three were male and two were female. Multiple lesions were noted in two cases. The lesions were Intradermal and had a peculiar histologic pattern with intracytoplasmic inclusions. By electron microscopy, the inclusions were composed of a meshwork of both fibrils and fine granules and have no limiting membrane. No virus-like particle could be identified in the proliferating cells. Follow-up information was available in all five cases; one had recurring tumors.     

Deficits in radial-arm maze learning in aged rats

The present study was designed to investigate the possible deficits in the place learning on the 8-arm radial maze in aged rats. In this task, reward was given in the 4 predetermined arms. Aged rats (27 months old, N = 7) acquired this task more slowly than young rats (12 months old, N = 11), and didn't reach to the performance level of the young rats within 80 training trials. Analysis of error choices revealed that the aged animals first entered in the unbaited arms more often than the young rats, whereas there was no difference in the number of re-entered choices to the baited and unbaited arms between the aged and young animals. Therefore, it was concluded that learning deficits in aged rats were attributed to deficits in the reference memory but not in the working memory.     

High Frequency of Antibiotic-Associated Diarrhea due to Toxin A-Negative, Toxin B-Positive Clostridium difficile in a Hospital in Japan and Risk Factors for Infection

Patients hospitalized in a hospital with a high incidence of antibiotic-associated diarrhea due to toxin A-negative, toxin B-positive (A–/B+) Clostridium difficile were retrospectively investigated to determine the clinical manifestations and risk factors for infection. Of 77 Clostridium difficile isolates obtained from 77 patients during the 1-year investigation period, 30 were A–/B+ and 47 were toxin A-positive, toxin B-positive (A+/B+). By pulsed-field gel electrophoresis analysis, 23 of the 30 A–/B+ strains were outbreak-related, suggesting nosocomial spread of a single type of bacterium, which mainly affected patients in the wards of respiratory medicine, hematology and neurology. Using regression analysis, three factors were found to be associated with infection by A–/B+ isolates: (i) exposure to antineoplastic agents (P=0.01, odds ratio [OR]=5.1), (ii) the use of nasal feeding tubes (P=0.008, OR=5.2), and (iii) assignment to a certain internal medicine ward (P=0.05, OR=3.0). Between patients with Clostridium difficile-associated diarrhea caused by A–/B+ strains and those with A+/B+ strains, no statistically significant difference was found in body temperature, serum concentration of C-reactive protein, leukocyte count in whole blood, frequency of diarrhea, or type of underlying disease. These results indicate that A–/B+ strains of Clostridium difficile can cause intestinal infection in humans and they spread nosocomially in the same manner as A+/B+ strains.     

CT myelography with intramedullary enhancement in cervical spondylosis

The authors describe seven cases of cervical spondylosis in which small high-density areas were detected in the spinal cord on delayed computerized tomographic (CT) myelography. These high-density areas are believed to represent cavities or areas of cystic necrosis. In all seven cases the cervical spinal canal was narrow, and the spondylosis was located at multiple levels, causing a so-called "pincer effect." On the CT scans the high-density areas resembled fried eggs in the gray matter. These areas were localized near the abnormal cervical discs. In two cases in which the Brown-Séquard syndrome was noted, the symptoms could be attributed to the morphology of the high-density area on the affected side of the cord. Following decompressive surgery, most of the symptoms improved except for numbness of the upper extremities and motor weakness of hands.     

Lessons learned from lower urinary tract complications of anorectoplasty for imperforate anus with rectourethral/rectovesical fistula: Laparoscopy-assisted versus posterior sagittal approaches

PurposeTo report the sequelae of and preventive strategies for selected lower urinary tract (LUT) complications, i.e., posterior urethral diverticulum (PUD), intraoperative LUT injuries, postoperative dysuria, and fistula recurrence in male imperforate anus (IA) with rectourethral/rectovesical (RU/RV) fistula after laparoscopy-assisted anorectoplasty (LAARP) or posterior sagittal anorectoplasty (PSARP).Methods153 boys with IA and RU/RV fistula treated 1986–2019 by LAARP (n = 56) or PSARP (n = 97) at two unrelated institutes were studied retrospectively.ResultsAfter mean follow-up of 17.0 years (range: 36.5 days-32.0 years), the overall incidences of LUT complications were: LAARP (6/56; 10.7%); PSARP (7/97; 7.2%); p = 0.55, comprising PUD: LAARP (n = 5), PSARP (n = 0); p = 0.006; injuries: LAARP (n = 0), PSARP (n = 5); p = 0.16; dysuria: LAARP (n = 1), PSARP (n = 1); p>0.999; and recurrence: LAARP (n = 0), PSARP (n = 1); p>0.999. Mean onset of PUD was 5.1 years (range: 1.0–15.1 years). Treatment: PUD: surgery (n = 2/5), conservative (n = 3/5); injuries: intraoperative repair (n = 5/5); dysuria: conservative (n = 2/2), and recurrence: redo PSARP (n = 1/1).ConclusionsStrategies devised to improve dissection accuracy resolved the specific technical issues causing LUT complications (remnant RU fistula dissection in LAARP and blind posterior access in PSARP). Currently, the incidence of new cases of PUD and LUT injuries is zero.Level of Evidence: Level III     

Nomograms predicting extra- and early intrahepatic recurrence after hepatic resection of hepatocellular carcinoma

BackgroundExtrahepatic recurrence and early intrahepatic recurrence of hepatocellular carcinoma after hepatic resection are indicative of poor prognoses. We aimed to develop nomograms to predict extrahepatic recurrence and early intrahepatic recurrence after hepatic resection.MethodsThe participants of this study were 1,206 patients who underwent initial and curative hepatic resection for hepatocellular carcinoma. Multivariate logistic regression analyses using the Akaike information criterion were used to construct nomograms to predict extrahepatic recurrence and early intrahepatic recurrence (within 1 year of surgery) at the first recurrence sites after hepatic resection. Performance of each nomogram was evaluated by calibration plots with bootstrapping.ResultsExtrahepatic recurrence was identified in 95 patients (7.9%) and early intrahepatic recurrence in 296 patients (24.5%). Three predictive factors, α-fetoprotein >200 ng/mL, tumor size (3–5 cm or >5 cm vs ≤3 cm), and image-diagnosed venous invasion by computed tomography, were adopted in the final model of the extrahepatic recurrence nomogram with a concordance index of 0.75. Tumor size and 2 additional predictors (ie, multiple tumors and image-diagnosed portal invasion) were adopted in the final model of the early intrahepatic recurrence nomogram with a concordance index of 0.67. The calibration plots showed good agreement between the nomogram predictions of extrahepatic recurrence and early intrahepatic recurrence and the actual observations of extrahepatic recurrence and early intrahepatic recurrence, respectively.ConclusionWe have developed reliable nomograms to predict extrahepatic recurrence and early intrahepatic recurrence of hepatocellular carcinoma after hepatic resection. These are useful for the diagnostic prediction of extrahepatic recurrence and early intrahepatic recurrence and could guide the surgeon’s selection of treatment strategies for hepatocellular carcinoma patients.