Prefabrication of bone by vascular induction: an experimental study in rabbits.

The various methods of prefabricating flaps include vascular induction through staged transfer; pretransfer delay, expansion, and grafting; the use of alloplastic materials; and tissue bioengineering. In this experimental study, vascular induction was used to provide an axial vascular pedicle to randomly nourished tissue. Twenty-six New Zealand rabbits, ages and weights ranging between 6 months-1 year and 1.5-3.5 kg, respectively, were used. The sex difference was not considered. The deep inferior epigastric artery and vein were used to carry blood and were placed into a segment of femur to prefabricate the bone. Four weeks later, the viability of the segment of bone prefabricated by new axial pedicle was shown by scintigraphic study, and the new axial pedicle was ready for free transfer.     

First branchial cleft fistula presenting with external opening on earlobe

First branchial cleft fistula is a rare congenital malformation of the head and neck with an incidence of less than 10% of all branchial cleft defects. We herein report a 15-year-old girl who had a cystic mass in the postauricular region with an external opening on the posterior face of the earlobe. Surgical exploration revealed that a second sinus tract was passing through the conchal cartilage without going beyond the skin of the external acoustic meatus. The mass and the tract were excised along with the opening on the earlobe as well as the skin island surrounding the opening. The case was treated surgically with success .The significance of our case was the location of external opening on the earlobe.     

Liver transplantation for acute liver failure in a SARS-CoV-2 PCR-positive patient

Current guidelines recommend deferring liver transplantation (LT) in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection until clinical improvement occurs and two PCR tests collected at least 24 hours apart are negative. We report a case of an 18-year-old, previously healthy African-American woman diagnosed with COVID-19, who presents with acute liver failure (ALF) requiring urgent LT in the context of SARS-CoV-2 polymerase chain reaction (PCR) positivity. The patient was thought to have acute Wilsonian crisis on the basis of hemolytic anemia, alkaline phosphatase:bilirubin ratio <4, AST:ALT ratio >2.2, elevated serum copper, and low uric acid, although an unusual presentation of COVID-19 causing ALF could not be excluded. After meeting criteria for status 1a listing, the patient underwent successful LT, despite ongoing SARS-CoV-2 PCR positivity. Remdesivir was given immediately posttransplant, and mycophenolate mofetil was withheld initially and the SARS-CoV-2 PCR test eventually became negative. Three months following transplantation, the patient has made a near-complete recovery. This case highlights that COVID-19 with SARS-CoV-2 PCR positivity may not be an absolute contraindication for transplantation in ALF. Criteria for patient selection and timing of LT amid the COVID-19 pandemic need to be validated in future studies.     

A study on impact and tensile strength of acrylic resin filled with short ultra-high molecular weight polyethylene fibers

In dentistry, acrylates have been used for preparing denture bases for 50 years. Although polymethylmethacrylates (PMMA) are known to be an ideal base material, they possess some undesirable mechanical properties, especially their impact strength and tensile strength, which appear to be unsatisfactory for some applications. Additives and fibers have therefore been used to enhance and improve these properties over the last two decades. The present article describes the mechanical properties, impact and tensile strength of PMMA reinforced with chopped ultra-high molecular weight polyethylene fiber (6 mm long). It was found that, although the processing involved for high loading of fibers into the PMMA was difficult, the resulting improvement of impact strength was substantial.     

Highly efficient ex vivo gene transfer to the transplanted heart by means of hypothermic perfusion with a low dose of adenoviral vector

BACKGROUND: Hypothermic conditions required for donor heart preservation may reduce gene-transfer efficiency. Experiments were designed to determine whether a perfusion technique could improve the efficiency of gene transfer to donor hearts. METHODS: An adenoviral vector encoding beta-galactosidase (3.5 x 10(8) plaque-forming units) was infused into explanted rat hearts under 4 conditions (each n = 6): (1) the virus was diluted in 350 microL of University of Wisconsin solution and infused as a high-pressure bolus into the coronary arteries of donor hearts through the aortic root; (2) the virus was diluted in 5 mL of University of Wisconsin solution and circulated by means of a peristaltic pump (flow, 0.75 mL/min) through the vasculature of the donor heart for 30 minutes; (3) 5 mL of viral solution was circulated as for group 2 for 15 minutes; and (4) 5 mL of viral solution was circulated for 5 minutes at a flow rate of 2.4 mL/min. Transduced hearts were transplanted into the abdomen of syngeneic rats, and transgene expression was assessed by means of immunoassay 4 days later. RESULTS: The median beta-galactosidase content was (1) 45.0 ng/mg protein (25th-75th percentile, 33-73 ng/mg), (2) 640 ng/mg protein (25th-75th percentile, 614-878 ng/mg), (3) 493.8 ng/mg protein (25th-75th percentile, 456-527 ng/mg), and (4) 503.3 ng/mg protein (25th-75th percentile, 475-562 ng/mg; P <.01 for group 2 vs group 1, and P <.05 for groups 3 and 4 vs group 1). Transgene expression was predominantly in myocytes and favored the subepicardial region of the right ventricle. CONCLUSION: Hypothermic perfusion of the donor heart with an adenoviral vector resulted in efficient transgene expression compared with that induced by a single bolus injection.