Potential utility of new surgical hemostatic film using Hydrofit®: a preliminary study.

We developed a surgical hemostatic film using Hydrofit® (Hydrofit® film). This film is prepared by reacting Hydrofit® with water in advance, and it can be used in the same way as an accessory silicone sheet. In addition, unlike the silicone sheet, there is no need to remove the Hydrofit® film from the body. In the present study, we describe the hemostatic effect of our new method using Hydrofit® film. We created a pulsatile flow circuit model using a ventricular assist device and a vascular graft. The circuit was filled with water, and the systolic pressure was adjusted to ≥ 130 mmHg. The artificial blood vessel was punctured by an 18-G needle. Operations to prevent water from leaking were attempted through either a conventional method using a silicone sheet or our new method using Hydrofit® film. In the 180-s trial, 14 attempts (93.3%) with the Hydrofit® film were successful. In the silicone sheet group, 13 attempts (86.7%) were successful before the silicone sheet was peeled off, and hemostasis was maintained in 10 (66.5%) cases after the silicone sheet was removed. After short-duration hemostasis for 60 s, good waterproofing was obtained in the Hydrofit® film group (success in 17 cases [85%]). In contrast, in the silicone sheet group, 10 attempts (50%) were successful before the silicone sheet was peeled off, and hemostasis was maintained in only 7 (35%) cases after the silicone sheet was removed. Hydrofit® film showed good hemostatic performance in the pulsatile flow circuit model.

Egg White Hydrolysate Retains the Nutritional Value of Proteins and Is Quickly Absorbed in Rats.

Egg white protein has a high net protein utilisation, with a score of 100 in the amino acid rating system. Although the enzymatic breakdown of egg white yields hydrolysates that are rapidly absorbed and various physiological activities can be expected from them, flavouring egg white to meet taste requirements as a food has been a difficult challenge. Herein, we developed a high-molecular-weight egg white hydrolysate and compared the absorption rate and nutritional value of the hydrolysate with those of egg white proteins obtained from raw materials, whey proteins, and hydrolysates, also known as high-quality proteins. The absorption rate of egg white hydrolysates was faster than that of egg white and whey proteins in portal vein cannulated rats, and their bioavailability values were higher than those of whey proteins and hydrolysates. According to the protein digestibility-corrected amino acid score and digestible indispensable amino acid score, the scores for egg white hydrolysates were equivalent to those of egg white and whey proteins but higher than those of whey hydrolysates. Our results show that egg white hydrolysates maintain the nutritional value of egg whites and are rapidly absorbed by the body.

Breaking the Limit of Cardiovascular Regenerative Medicine: Successful 6-Month Goat Implant in World's First Ascending Aortic Replacement Using Biotube Blood Vessels.

This study investigated six-month outcomes of first models of ascending aortic replacement. The molds used to produce the Biotube were implanted subcutaneously in goats. After 2-3 months, the molds were explanted to obtain the Biotubes (inner diameter, 12 mm; wall thickness, 1.5 mm). Next, we performed ascending aortic replacement using the Biotube in five allogenic goats. At 6 months, the animals underwent computed tomography (CT) and histologic evaluation. As a comparison, we performed similar surgeries using glutaraldehyde-fixed autologous pericardial rolls or pig-derived heterogenous Biotubes. At 6 months, CT revealed no aneurysmalization of the Biotube or pseudoaneurysm formation. The histologic evaluation showed development of endothelial cells, smooth muscle cells, and elastic fibers along the Biotube. In the autologous pericardium group, there was no evidence of new cell development, but there was calcification. The histologic changes observed in the heterologous Biotube group were similar to those in the allogenic Biotube group. However, there was inflammatory cell infiltration in some heterologous Biotubes. Based on the above, we could successfully create the world's first Biotube-based ascending aortic replacement models. The present results indicate that the Biotube may serve as a scaffold for aortic tissue regeneration.

In vitro evaluation of the hemostatic effect of method involving the combined use of Hydrofit® and Spongel®.

OBJECTIVE: We developed an effective hemostatic method using Hydrofit® and a hemostatic gelatin sponge (Spongel®). We evaluated the hemostatic effect in comparison to the conventional silicone sheet method. METHODS: A simulated circuit was created using the pump of a Nipro ventricular assist system and a prosthetic graft. A hole was made in the graft by a needle and three hemostatic methods were applied: the silicone sheet method (SS) using Hydrofit® and a silicone sheet, the bread and butter method (BB) using Hydrofit® and a gelatin sponge instead of a silicone sheet, and French toast method (FT) using Hydrofit® and a gelatin sponge over which water was poured before compression. The amount of leakage before and after the application each of the methods was measured according to the compression time. RESULTS: In the 60 s compression, the amount of leakage after SS, BB, and FT was 0.4 ± 0.8, 0.2 ± 0.6, and 0 ± 0.0 ml, respectively, and FT showed no leakage. In the 30 s compression, the amount of leakage after SS, BB, and FT was 14.2 ± 27.9, 1.0 ± 3.2, and 7.8 ± 22.6 ml, respectively, and did not differ to a statistically significant extent. CONCLUSIONS: The method of combining Hydrofit® and Spongel® could obtain reliable hemostasis in 60 s.

Expression, oxidative refolding, and characterization of six-histidine-tagged recombinant human LECT2, a 16-kDa chemotactic protein with three disulfide bonds.

Human LECT2 is a 16-kDa chemotactic protein that consists of 133 amino acids and three intramolecular disulfide bonds. Here, we present the oxidative refolding of (His)(6)-LECT2, an N-terminally (His)(6)-tagged recombinant protein of human LECT2. (His)(6)-LECT2 was overproduced in Escherichia coli in the form of insoluble aggregates, solubilized with 8 M urea in the presence of 10 mM DTT, and purified and refolded on Ni-NTA agarose by lowering the urea concentration before the elution. This process, however, gave a mixture of oligomers of (His)(6)-LECT2 as well as the monomer, whose composition was as low as 36%. The oligomers formed as a result of incorrect intermolecular disulfide bonds. After the refolding on Ni-NTA agarose (step 1), the disulfide bonds were shuffled using a glutathione redox buffer (step 2) and the remaining thiols were completely oxidized (step 3) to improve the yield of correctly folded, monomeric (His)(6)-LECT2. The monomer composition was significantly improved to 81% by the three-step refolding method and the monomer thus obtained was shown to have the same conformation as the authentic LECT2 produced in CHO cells by CD and NMR spectroscopies. The yield of (His)(6)-LECT2 was 1.0 mg/L E. coli culture and was 16 times as high as that in our previous report, in which (His)(6)-LECT2 was purified from the soluble fractions of E. coli cell lysates.