Combination product of dermal matrix, preconditioned human mesenchymal stem cells and timolol promotes wound healing in the porcine wound model.

A combination product of human mesenchymal stem/stromal cells (MSCs) embedded in an extracellular matrix scaffold and preconditioned with hypoxia and the beta-adrenergic receptor antagonist, timolol, combined with sustained timolol application post implantation, has shown promising results for improving wound healing in a diabetic mouse model. In the present study, we extend those findings to the more translatable large animal porcine wound model and show that the combined treatment promotes wound reepithelialization in these excisional wounds by 40.2% and increases the CD31 immunostaining marker of angiogenesis compared with the matrix control, while maintaining an accumulated timolol plasma concentration below the clinically safe level of 0.

Bidirectional Ductal Shunting and Preductal to Postductal Oxygenation Gradient in Persistent Pulmonary Hypertension of the Newborn.

Background: The aim was to evaluate the relationship between the direction of the patent ductus arteriosus (PDA) shunt and the pre- and postductal gradient for arterial blood gas (ABG) parameters in a lamb model of meconium aspiration syndrome (MAS) with persistent pulmonary hypertension of the newborn (PPHN).

Methods: PPHN was induced by intermittent umbilical cord occlusion and the aspiration of meconium through the tracheal tube. After delivery, 13 lambs were ventilated and simultaneous 129 pairs of pre- and postductal ABG were drawn (right carotid and umbilical artery, respectively) while recording the PDA and the carotid and pulmonary blood flow.

PRESUMED PHOTORECEPTOR DYSPLASIAS IN PEREGRINE FALCONS ( FALCO PEREGRINUS) AND PEREGRINE FALCON HYBRIDS.

We describe a case series of photoreceptor dysplasia with secondary retinal degeneration in juvenile Peregrine Falcons. Six Peregrine Falcons ( Falco peregrinus) and three Peregrine Falcon × Prairie Falcon ( Falco mexicanus) hybrids had early-life visual deficits. Eight birds had visual defects shortly after hatching, and one bird had visual deficits first noticed at 5 mo of age.

Altered Repolarization Reserve in Failing Rabbit Ventricular Myocytes: Calcium and β-Adrenergic Effects on Delayed- and Inward-Rectifier Potassium Currents.

Background: Electrophysiological remodeling and increased susceptibility for cardiac arrhythmias are hallmarks of heart failure (HF). Ventricular action potential duration (APD) is typically prolonged in HF, with reduced repolarization reserve. However, underlying K current changes are often measured in nonphysiological conditions (voltage clamp, low pacing rates, cytosolic Ca buffers).

Genetically Encoded Biosensors Reveal PKA Hyperphosphorylation on the Myofilaments in Rabbit Heart Failure.

Rationale: In heart failure, myofilament proteins display abnormal phosphorylation, which contributes to contractile dysfunction. The mechanisms underlying the dysregulation of protein phosphorylation on myofilaments is not clear.

Objective: This study aims to understand the mechanisms underlying altered phosphorylation of myofilament proteins in heart failure.

Is Continuous Flow Superior to Pulsatile Flow in Single Ventricle Mechanical Support? Results from a Large Animal Pilot Study.

Durable mechanical support in situations of physiologic single ventricle has been met with little success so far, particularly in small children. We created an animal model to investigate whether pulsatile or continuous flow would be superior. Three 1 month old sheep (10-16 kg) were instrumented.

Hemodynamic monitoring of large animal chronic studies after median sternotomy: experiences with different telemetric physiological devices.

Telemetric physiological monitoring systems (TPMS) have enabled accurate continuous measurement of animal blood pressures and flows. However, few studies describe approaches for use of TPMS in the great vessels or inside the heart. We describe our initial experiences using two types of TPMSs.

Multispectral fluorescence lifetime imaging system for intravascular diagnostics with ultrasound guidance: in vivo validation in swine arteries.

Fluorescence lifetime technique has demonstrated potential for analysis of atherosclerotic lesions and for complementing existing intravascular imaging modalities such as intravascular ultrasound (IVUS) in identifying lesions at high risk of rupture. This study presents a multimodal catheter system integrating a 40 MHz commercial IVUS and fluorescence lifetime imaging (FLIm) using fast helical motion scanning (400 rpm, 0.75 mm/s), able to acquire in vivo in pulsatile blood flow the autofluorescence emission of arterial vessels with high precision (5.

Fetal cardiac intervention: improved results of fetal cardiac bypass in immature fetuses using the TinyPump device.

Objective: Fetal cardiac surgery is a potential innovative treatment for certain congenital heart defects that have significant mortality and morbidity in utero or after birth, but it has been limited by placental dysfunction after fetal cardiac bypass. We have used the TinyPump device for fetal cardiac bypass in sheep fetuses at 90 to 110 days gestation.

Methods: Ten mixed-breed pregnant ewes were used over a period of 6 months, and 10 fetuses were placed on bypass for 30 minutes.

Challenges in longer-term mechanical support of fontan circulation in sheep.

Single ventricle congenital heart defects are usually palliated with the end result of a Fontan circulation. Despite improving results, this circulation is still associated with long-term failure. We previously developed an animal model of mechanical cavopulmonary circulation support that was successful in the acute and mid-term period.

Dynamic tracheal occlusion improves lung morphometrics and function in the fetal lamb model of congenital diaphragmatic hernia.

Background: Congenital diaphragmatic hernia (CDH) is associated with significant neonatal morbidity and mortality. Although prenatal complete tracheal occlusion (cTO) causes hypoplastic CDH lungs to enlarge, improved lung function has not been demonstrated. Furthermore, cTO interferes with the dynamic pressure change and fluid flow associated with fetal breathing.

Intradiscal thermal therapy using interstitial ultrasound: an in vivo investigation in ovine cervical spine.

Study Design: In vivo investigation of intradiscal ultrasound thermal therapy in ovine cervical spine model.

Objective: To evaluate the potential of interstitial ultrasound for selective heating of intradiscal tissue in vivo.

Summary Of Background Data: Application of heat in the spine using resistive wire and radiofrequency current heating devices is currently being used clinically for minimally invasive treatment of discogenic low back pain.

Intradiscal thermal therapy does not stimulate biologic remodeling in an in vivo sheep model.

Study Design: Thermal energy was delivered in vivo to ovine cervical discs and the postheating response was monitored over time.

Objectives: To determine the effects of two distinctly different thermal exposures on biologic remodeling: a "high-dose" regimen intended to produce both cellular necrosis and collagen denaturation and a "low-dose" regimen intended only to kill cells.

Summary Of Background Data: Thermal therapy is a minimally invasive technique that may ameliorate discogenic back pain.

Limbic dermoid in a New Zealand White rabbit (Oryctolagus cuniculus).

Superficial keratectomy was performed in a New Zealand White rabbit for a suspected limbic dermoid. Histology confirmed the diagnosis. Ocular dermoids have been reported in a variety of laboratory animals.