Basic in vitro experiment on the adhesive effects of sheet-type hemostatic agents used in combination with a liquid fibrin sealant.

BACKGROUND AND PURPOSE: Various hemostatic agents have been used quite effectively for hemostasis, as well as for providing effective adhesion during laparoscopic partial nephrectomies. In this study, we investigated the adhesiveness to the renal tissue of some sheet-type hemostatic agents used in combination with a liquid fibrin sealant. MATERIALS AND METHODS: In Experiment A, component solutions of the fibrin glue (liquid fibrin sealant) were dripped onto a kite string placed annularly on a porcine kidney slice. Then, one of the sheet-type hemostats--namely, the collagen, gelatin, or cellulose hemostat--was placed on the slices, and a string scale was used to measure the force needed to pull the string apart vertically from the kidney slice. Twelve slices were used for each group, and the weight data were analyzed statistically. The tissue adhering to each sheet-type hemostatic agent was fixed in formalin and sliced and then examined by light microscopy after hematoxylin and eosin staining. In Experiment B, the solutions were dripped onto the sheet-type hemostatic agent placed first on the slice, and the force needed for pulling apart the hemostat sheet from the slice was similarly examined. RESULTS: The combination of fibrin glue plus a collagen hemostat was clearly superior in Experiment A, but the hemostat and renal tissue could be pulled apart more easily in Experiment B. These results showed that fibrin glue could not exert its expected adhesive effect unless it is used in combination with another hemostatic agent or is directly applied to renal tissue. CONCLUSION: It is important to obtain further comparative data among agents and select the appropriate agents, taking into consideration the type of surgery.

Combination of a liquid fibrin sealant with sheet-type hemostatic agents: experimental evaluation in partial nephrectomy animal model.

Liquid fibrin sealants, together with sheet-type hemostatic agents, have been used during partial nephrectomies to secure effective hemostasis at the suture site. Using animal kidneys, we investigated which hemostatic agent might adhere most effectively to the renal tissue and serve best as a bolster. Liquid fibrin sealant alone, or in combination with a sheet-type hemostat, such as collagen, gelatin or oxidized-cellulose hemostat, was applied to the cut surface of the kidney of anesthetized rabbits, and the differences in the degree of adherence to the kidney and resultant hemostatic efficacy were evaluated. Histological analyses were also carried out to compare the degree of adherence of each of the aforementioned hemostats to the kidney tissue. Fibrin sealant plus the collagen or gelatin hemostat was found to have a stronger hemostatic effect than fibrin sealant applied alone or fibrin sealant plus oxidized-cellulose hemostat. The histological investigation showed that the fibrin sealant adhered well to kidney tissue when it was applied with the collagen or gelatin hemostat, showing the advantage of combining these two materials for achieving effective hemostasis. Fibrin sealant used in combination with the collagen or gelatin hemostat was the most suitable for obtaining a reinforced hemostatic effect at the suture site in a partial nephrectomy animal model.

Pharmacokinetic study of interleukin-2 following intravenous injection in hemodialysis patients with renal cell carcinoma.

The purpose of the present study is to determine the change in blood concentration of interleukin-2 (IL-2) after intravenous injection in hemodialysis patients and to assess its safety. Four hemodialysis patients who underwent nephrectomy due to renal cell carcinoma were treated with IL-2 at a dose of 350 000-700 000 JRU by intravenous injection. Pharmacokinetic parameters were analyzed from the serum IL-2 concentration, which reached its peak just after the end of infusion, followed by biphasic elimination, and was below the detection limit in all patients at 24 h postinfusion. In comparison with patients with normal renal function, the volume of distribution in the serum compartment was almost comparable (3820 +/- 2020 mL). Clearance (50.47 +/- 11.50 mL/min) decreased to 40%, and the half-life of the distribution phase (0.45 +/- 0.19 h) and that of the terminal phase (1.72 +/- 0.20 h) were distinctly longer. The area under the blood concentration-time curve was about two-fold higher than that of non-hemodialysis patients. In all patients, there were no serious adverse reactions. The results of the present study suggest that intravenous IL-2 therapy can be safely performed in hemodialysis patients.

Concentration gradient of oxalate from cortex to papilla in rat kidney.

BACKGROUND: The kidney eliminates the major fraction of plasma oxalate. It is well known that oxalate is freely filtered by glomeruli and secreted by the proximal tubules. However, the renal handling of oxalate in distal nephrons, which is considered as playing an important role in stone formation, remains obscure. METHODS: At 15-180 min after intravenous injection of 14C-oxalate to rats, the intrarenal localization of radioactivity was quantitatively measured by the radioluminographic method using a bioimaging analyzer. Tissue radioactivity was compared with plasma, and urinary radioactivities were measured by a liquid scintillation counter. The control study was conducted with 14C-inulin. RESULTS: The radioactivity of 14C-oxalate in the papilla was 10 times greater than in the cortex and eight times greater than in the medulla 180 min after injection when almost no radioactivity was present in the urine. In contrast, the radioactivity of 14C-inulin was nine times less in the papilla than in the cortex at the same time. CONCLUSION: Oxalate remains in the renal papilla for an extended period. This accumulation of oxalate may be attributed to calcium oxalate crystal fixation along the deep nephron which is considered to be the first step of stone formation.

Extraperitoneal laparoscopic Lich-Gregoir antireflux plasty for primary vesicoureteral reflux.

We performed laparoscopic Lich-Gregoir antireflux plasty on 4 patients with primary vesicoureteral reflux. All procedures were conducted using the extraperitoneal approach. The average surgical time was 230 min. There were no complications. After surgery, voiding cysturethrograms showed no reflux in all patients.

The preventive effect of sodium pentosan polysulfate against renal stone formation in hyperoxaluric rats.

Sodium pentosan polysulfate (SPP), a semi-synthetic glycosaminoglycan, was administered to rats with hyperoxaluria, induced by a vitamin B6 deficient diet, as a model of calcium oxalate stone formation. We studied the preventive effects of SPP on stone formation as well as its inhibitory effects on stone growth by autoradiography and radioluminography after intravenous injection of (14)C-oxalate. The rats were divided into non-treated and SPP-treated groups. The non-treated rats were divided into three groups: one group was fed a regular diet, while the other two groups were fed a vitamin B6 deficient diet for 2 and 4 weeks, respectively. The SPP-treated rats were divided into two groups: one group was intravenously injected with SPP from the start of the vitamin B6 deficient diet for a total of 4 weeks and the other group was injected with the same amount of SPP after 2 weeks of the diet for 2 weeks. (14)C-oxalate renal macroautoradiograms were prepared, and calcium oxalate deposits in the renal tissues were compared between the non-treated and SPP-treated groups. The preventive effects on calcium oxalate stone formation were clearly observed in the group injected with SPP for 4 weeks. Even in the other SPP-treated group, in which the administration of SPP was started at 2 weeks after the start of the diet when calcium oxalate stone formation was already observed, the size of the calcium oxalate deposits observed after 4 weeks was smaller than that in the non-treated group fed a vitamin B6 deficient diet for 4 weeks. In conclusion, our results show that SPP has not only preventive effects on calcium oxalate stone formation but also growth inhibitory effects on stones in hyperoxaluric rats.

Metastatic urinary bladder tumor from extragonadal germ cell tumor: a case report.

A 37-year old male patient complained of lower back pain. Investigations revealed a retroperitoneal tumor and left-sided cervical lymphadenopathy without abnormal findings in both testicles. The diagnosis of extragonadal germ cell tumor was made based on a lymph node biopsy. Following chemotherapy and retroperitoneal lymphoadenectomy, at outpatient follow-up, beta-HCG elevated again. He complained of gross hematuria, cystoscopy showed a bladder tumor, and abdominal MRI scan showed a right ureteral tumor. Total cystectomy and right nephroureterectomy were performed, which revealed that the bladder and ureteral tumors were metastatic germ cell tumors. Six months later, the patient developed hepatic and mesenteric lymph node metastases that failed to respond to treatment, and died. Germ cell tumors metastasizing to the urinary tract are extremely uncommon, and this is the first report of bladder metastases, other than through direct invasion, from an extratesticular germ cell tumor.

NADPH-cytochrome P-450 reductase in the plasma membrane modulates the activation of hypoxia-inducible factor 1.

Hypoxia induces a group of physiologically important genes that include erythropoietin (EPO) and vascular endothelial growth factor (VEGF). Hypoxia-inducible factor 1 (HIF-1) was identified as a hypoxia-activated transcription factor; however, the molecular mechanisms that underlie hypoxia signal transduction in mammalian cells remain undefined. In this study, we found that a flavoprotein, NADPH-P450 reductase (NPR), could regulate the induction of EPO mRNA under hypoxic conditions. Hypoxic EPO mRNA induction in Hep3B cells was inhibited by diphenyleneiodonium chloride, which is an inhibitor of NADPH-dependent enzymes. NPR antisense cDNA was transfected into Hep3B cells, and NPR-deficient hepatocyte cells (NPR(-) cells) were established. NPR(-) cells lacked EPO induction under hypoxia, and HIF-1alpha in NPR(-) cells did not respond to either transcriptional activation or translocation to the nucleus based on electrophoretic mobility shift assays and reporter gene assay including hypoxia response element. In contrast, NPR overexpression in Hep3B cells enhanced the DNA binding activity of HIF-1alpha by luciferase reporter gene assay. A study with HeLa S3 cells produced the same results. Furthermore, anti-NPR IgG inhibited EPO induction. EPO induction inhibited by diphenyleneiodonium chloride was recovered by bovine serum albumin-NADPH (a covalent binding complex of bovine serum albumin and NADPH) as well as NADPH. These results suggested that NPR located at the plasma membrane regulates EPO expression in hypoxia, including HIF-1 activation and translocation. We further studied the expression of NPR and VEGF mRNAs in human tumor tissues and found that the NPR mRNA levels were correlated with the VEGF mRNA levels, suggesting that NPR might be an important factor in the hypoxic induction of genes such as VEGF in vivo.