Improvement of porcine islet isolation by inhibition of trypsin activity during pancreas preservation and digestion using α1-antitrypsin

Porcine islets are considered to be a promising resource for xenotransplantation. However, it is difficult to isolate porcine islets because of the marked fragility and rapid dissociation. Endogenous trypsin is one of the main factors to damage islets during the isolation procedure. Recent studies have suggested that trypsin inhibitors during the preservation of pancreas or the collagenase digestion can improve the result of islet isolation. In this study, we examined whether α1-antitrypsin (Aralast?), which inhibits several endogenous proteases and has immunomodulatory properties, can protect islets from the proteases and improve the results of porcine islet isolation. Twelve porcine pancreata were divided into three groups: without Aralast group (standard, n = 5), preserved with Aralast using the ductal injection (DI) method (DI, n = 3), and with Aralast using the DI method and in the collagenase solution (DI+C, n = 4). Efficacy of islet isolation was assessed by islet yields, purity, and viability. The trypsin activity of the preservation and the digestion solution during the isolation procedure was measured. During islet isolation, the trypsin activity in DI+C group was significantly inhibited compared to the standard group, whereas DI group showed less effect than DI+C group. The average of postpurification islet equivalents (IEQ) per pancreas weight in the DI+C group was significantly higher than the standard group (standard: 3516 ± 497 IEQ/g, DI: 4607 ± 1090 IEQ/g, DI+C: 7097 ± 995 IEQ/g; p = 0.017 between standard and DI+C). In the DI+C group, stimulation index was higher than in other groups, although there was no significant difference. The presence of Aralast in both DI solution and collagenase solution markedly inhibited trypsin activity during pancreas digestion procedure and improved the porcine islet isolation. Inhibition of trypsin activity by Aralast could improve porcine islet isolation.     

Islet purification method using large bottles effectively achieves high islet yield from pig pancreas

Porcine islets are a promising resource for xenotransplantation. However, low efficacy of islet isolation because of their marked fragility remains a problem. Recently we found that the standard purification method using COBE 2991 cell processor (COBE) with Ficoll density gradient solution damaged islets mechanically by high shearing force. In this study, we evaluated our new purification method using large plastic bottles for the efficacy of islet purification. Ten porcine pancreata were used. The average warm ischemic time was over 40 min; therefore, these pancreata were considered to be in a marginal condition. After digestion, the digested tissue was divided into three groups. Each group was purified using either top loading method with bottle (top group) or bottom loading method with bottle (bottom group) or standard COBE method (COBE group). Islet yield per pancreas weight (IEQ/g) and the rate of postpurification recovery in the top group were significantly higher than the COBE group (top: 8060 ± 1652 IEQ/g, bottom: 4572 ± 614 IE/g, COBE: 3900 ± 734 IE/g. p < 0.02 in top vs. COBE; top percentage of recovery: 99.3 ± 12.3%, bottom: 62.6 ± 8.8%, COBE: 49.5 ± 6.7%, p < 0.02 in top vs. bottom and COBE). The average sizes of purified islets in the top and bottom groups were significantly larger than COBE group (Average diameter top: 156 ± 8 μm, bottom: 147 ± 6 μm, COBE: 119 ± 6 μm, p < 0.01 in top vs. COBE and in bottom vs. COBE), which indicated that bottle method can reduce shear force during purification. Our new purification using top loading bottle method enabled us to obtain a high yield of porcine islets from marginal pancreata.     

Analysis of flow within a left ventricle model fully assisted with continuous flow through the aortic valve

Blood compatibility of a ventricular assist device (VAD) depends on the dynamics of blood flow. The focus in most previous studies was on blood flow in the VAD. However, the tip shape and position of the VAD inflow cannula influence the dynamics of intraventricular blood flow and thus thrombus formation in the ventricle. In this study, blood flow in the left ventricle (LV) under support with a catheter-type continuous flow blood pump was investigated. The flow field was analyzed both numerically and experimentally to investigate the effects of catheter tip shape and its insertion depth on intraventricular flow patterns. A computational model of the LV cavity with a simplified shape was constructed using computer-aided design software. Models of catheters with three different tip shapes were constructed and each was integrated to the LV model. In addition, three variations of insertion depth were prepared for all models. The fully supported intraventricular flow field was calculated by computational fluid dynamics (CFD). A transparent LV model made of silicone was also fabricated to analyze the intraventricular flow field by the particle image velocimetry technique. A mock circulation loop was constructed and water containing tracer particles was circulated in the loop. The motion of particles in the LV model was recorded with a digital high-speed video camera and analyzed to reveal the flow field. The results of numerical and experimental analyses indicated the formation of two large vortices in the bisector plane of the mitral and aortic valve planes. The shape and positioning of the catheter tip affected the flow distribution in the LV, and some of these combinations elongated the upper vortex toward the ventricular apex. Assessment based on average wall shear stress on the LV wall indicated that the flow distribution improved the washout effect. The flow patterns obtained from flow visualization coincided with those calculated by CFD analysis. Through these comparisons, the numerical analysis was validated. In conclusion, results of these numerical and experimental analyses of flow field in the LV cavity provide useful information when designing catheter-type VADs.     

A silicone-based wire-reinforced tracheal tube with a hemispherical bevel reduces nasal morbidity for nasotracheal intubation

We tested the hypothesis that a silicone-based wire-reinforced tracheal tube with a hemispherical bevel is superior to a polyvinyl chloride (PVC)-based precurved tube with a conventional diagonal bevel for nasotracheal intubation. Eighty anesthetized paralyzed adults (ASA physical status I-II) requiring nasotracheal intubation for tonsillectomy were randomly allocated into two equal-sized groups for airway management with the silicone tracheal tube or PVC tracheal tube. Intubation was subdivided into three phases: 1). passage through the nose into the pharynx, 2). laryngoscope-guided passage into the glottic inlet, and 3). laryngoscope-guided passage into the trachea. A specific sequence of airway maneuvers was followed at each stage if it was unsuccessful. The number of attempts and intubation time were documented by an unblinded observer. The frequency of epistaxis and postoperative nasal complications was documented by blinded observers. There were no intubation failures. The number of attempts at pharyngeal (47 versus 56; P = 0.04) and tracheal (43 versus 55; P = 0.005) placement was smaller for the silicone tracheal tube, but the number of attempts at glottic placement was more (72 versus 49; P < 0.0001). Intubation time was similar. The frequency (32% versus 80%; P < 0.0001) and severity of epistaxis were less for the silicone tracheal tube. The total number of postoperative nasal symptoms was smaller for the silicone tracheal tube (10 versus 21; P < 0.05). We conclude that the pharyngeal and tracheal placement phases of nasotracheal intubation require fewer attempts with the silicone tracheal tube than the PVC tracheal tube but that the glottic placement phase requires more attempts. Nasal morbidity is less common with the silicone tracheal tube. IMPLICATIONS: The pharyngeal and tracheal placement phases of nasotracheal intubation require fewer attempts with a silicone-based wire-reinforced tracheal tube with a hemispherical bevel than with a polyvinyl chloride-based precurved tracheal tube with a conventional diagonal bevel, but the glottic placement phase requires more attempts. Nasal morbidity is less common with the silicone tracheal tube.     

Mini-dose (0.05 mg) intrathecal morphine provides effective analgesia after transurethral resection of the prostate

PURPOSE: To determine the optimal dose of intrathecal morphine that produces satisfactory analgesia with minimum side effects in elderly patients undergoing transurethral resection of the prostate (TURP). METHODS: In this double-blind prospective study, 42 patients undergoing TURP with spinal anesthesia were allocated to one of three groups. Group A (n = 14) received tetracaine, 10 mg, alone. Group B (n = 13) and Group C (n = 15) received morphine 0.05 mg and 0.10 mg, respectively, in combination with tetracaine. Postoperative pain, nausea and pruritus were evaluated using visual analogue scales (VAS). SpO(2) and respiratory rate were also assessed. RESULTS: At three, five, seven and 24 hr after spinal anesthesia, the VAS scores for pain in Groups B and C were significantly less than in Group A. Group C experienced significantly greater VAS scores for pruritus as compared to Groups A and B. There was no significant difference in the intensity of nausea among the three groups. No patient experienced hypoxemia (SpO(2) < 90%) and respiratory depression (respiratory rate < 10 beats*min(-1)) in any group. CONCLUSION: A dose of 0.05 mg in intrathecal morphine with spinal anesthesia would be optimal for elderly patients undergoing TURP.     

Intracaval endovascular ultrasonography for large adrenal and retroperitoneal tumors

BACKGROUND: An accurate diagnosis of inferior vena cava (IVC) invasion is important in deciding the surgical strategy for a large adrenal tumor. We investigated the diagnostic value of intracaval endovascular ultrasonography (ICEUS) for invasion of the IVC by a large adrenal tumor. METHODS: Nine of 163 patients with adrenal and retroperitoneal tumors underwent ICEUS between 1993 and 2002. Intravascular ultrasonography was performed through the right femoral vein with the use of an 8Fr, 20-MHz transducer. The diagnostic criterion for detecting IVC invasion with ICEUS was identification of destruction of a single echogenic layer of the IVC wall or identification of an intracaval tumor mass. The ICEUS finding was confirmed by pathologic examination. RESULTS: The mean diameter of the tumors in 9 patients undergoing ICEUS and resection was 12.6 cm (range, 8.6-16 cm). Pathologic diagnosis varied: adrenocortical carcinoma, 4; malignant pheochromocytoma, 1; leiomyosarcoma, 1; metastatic lung cancer, 1; paraganglioma, 1; and neurilemmoma, 1. Vascular invasion was identified in 2 patients by ICEUS and confirmed by examination of resected specimens. The sensitivity, specificity, and positive predictive values of ICEUS for the diagnosis of the IVC invasion were 100%, 100%, and 100%, respectively. However, these values for computed tomography were 100%, 14%, and 25%, respectively; and for cavography, 100%, 57%, and 40%, respectively. CONCLUSIONS: ICEUS provides confirmatory information regarding tumor invasion of the IVC. This modality also can assist in formulating an operative strategy for large adrenal or retroperitoneal tumors.     

Living-related liver transplantation for Alagille syndrome

Alagille syndrome (AGS) is an autosomal dominant genetic disorder characterized by chronic cholestasis, congenital heart disease, peculiar facies, butterfly-like vertebrae, and posterior embryotoxon. Liver dysfunction is the common presentation of AGS, and liver transplantation may be indicated. This study examines the outcome of living-related liver transplantation (LRLT) for AGS. Twenty patients with AGS (median age 5.0 years, range 0.6-12.9) underwent LRLT at Kyoto University Hospital between June 1990 and February 2002. Five potential donors were excluded because of paucity of intrahepatic bile ducts diagnosed by preoperative liver biopsy and one because of a hepatic vascular anomaly. The overall 5-year patient survival was 80.4%. Three patients died as the result of the following: complications related to surgery, heart failure caused by progressive pulmonary artery stenosis, and a graft with unsuspected bile duct paucity. Liver dysfunction was improved in all successful cases, and catch-up growth occurred in 90% of patients. LRLT is an efficacious treatment modality for AGS if donors are selected by cautious evaluation to rule out unsuspected bile duct paucity.     

FDG-PET for evaluating musculoskeletal tumors: a review

 Positron-emission tomography (PET) can provide an in vivo method for evaluating metabolism and physiology in normal and diseased tissues. Clinical trials with [¹⁸F]2-deoxy-2-fluoro-d-glucose (FDG), the most commonly used radiolabeled tracer for PET imaging, have demonstrated increased accumulation of FDG in several cancer tissues. In this article, we introduce the basic principles of FDG-PET and review current knowledge about FDG-PET for evaluating musculoskeletal tumors. Recent reports and our own experience suggest that FDG-PET cannot be a screening method for differential diagnosis between benign and malignant musculoskeletal lesions, including many neoplasms originating from different tissues altogether. FDG-PET might not accurately reflect the malignant potential of musculoskeletal tumors, but rather might implicate cellular components included in the lesions. A high accumulation of FDG can be observed in histiocytic, fibroblastic, and some neurogenic lesions, regardless of whether they are benign or malignant. More specific uses of FDG-PET, such as grading, staging, and monitoring of musculoskeletal sarcomas, should be considered for each tumor of a different histologic subtype. Received: October 2, 2001 RID="*"     

Interim evidence of the renoprotective effect of the angiotensin II receptor antagonist losartan versus the calcium channel blocker amlodipine in patients with chronic kidney disease and hypertension: a report of the Japanese Losartan Therapy Intended for Global Renal Protection in Hypertensive Patients (JLIGHT) Study

Background. Insufficiency of renal function and high blood pressure influence each other and eventually result in life-threatening endstage renal disease. It has been proposed that proteinuria per se is a determinant of the progression of chronic kidney disease (CKD). The therapeutic strategy for patients with proteinuric CKD and hypertension should therefore be targeted with a view not merely toward blood pressure reduction but also toward renoprotection. Methods. We examined the effect of the angiotensin (AT)₁ receptor antagonist losartan and the calcium channel blocker amlodipine, throughout a period of 12 months, on reduction of blood pressure and renoprotection. This was done by assessing amounts of urinary protein excretion, serum creatinine (SCr), and creatinine clearance (CCr) in patients with hypertension (systolic blood pressure [SBP] 140mmHg or diastolic blood pressure [DBP] 90mmHg) and CKD (male, body weight [BW] 60kg: 1.5 SCr < 3.0mg/dl; female or male BW < 60kg: 1.3 SCr < 3.0mg/dl), manifesting proteinuria of 0.5g or more/day. Losartan was administered once daily at doses of 25 to 100mg/day, and amlodipine was given once daily at 2.5 to 5mg/day. No antihypertensive combination therapy was allowed during the first 3-month period. Results. A 3-month interim analysis revealed that, despite there being no difference in blood pressure between the two groups, there was a significant reduction in 24-h urinary protein excretion in the losartan group (n = 43), but there was no change in the amlodipine group (n = 43). Analysis of stratified subgroups with proteinuria of 2g or more/day and less than 2g/day showed that losartan lowered proteinuria by approximately 24% in both subgroups, while amlodipine lowered proteinuria by 10%, but only in the subgroup of less than 2g/day (NS). SCr and CCr did not change throughout the period of 3 months in either group. No severe or fatal adverse event was experienced in either group during the study period. Conclusions. Losartan appeared to be efficacious for renoprotection in patients with proteinuric CKD and hypertension, with the mechanism being independent of its antihypertensive action.