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Biomedical subjects

G W Barone

Publications and source records attributed to G W Barone.

63 records · Page 4Linked to original sources
PubMed1989

Endothelial injury and vascular dysfunction associated with the Fogarty balloon catheter.

Endothelial-derived relaxing factor is an important modulator of vascular relaxation, and its production is very sensitive to endothelial injury. The abdominal aortas of five groups of rabbits were subjected to Fogarty balloon catheterization via the femoral artery. Some rabbits were killed immediately (time 0), and others were killed at weekly intervals. At time 0, isolated vascular rings sectioned from the abdominal aortas and suspended in tissue baths failed to exhibit any endothelial-derived relaxing factor dependent vascular relaxation. Vascular relaxation progressively returned but was not normal until 4 weeks after the initial injury. Morphologic changes studied by means of Evans blue dye and by scanning electron microscopy with silver staining corresponded well with these functional changes. At time 0, the delicate endothelium was completely denuded, but it progressively regenerated over the subsequent 4 weeks. This severe injury to the vascular endothelium and the resultant vascular dysfunction may result in an increased risk of early postoperative spasm and thrombosis after the use of a Fogarty balloon catheter.

Animals↗
PubMed1989

Morphological and functional techniques for assessing endothelial integrity: the use of Evans blue dye, silver stains, and endothelial derived relaxing factor.

The endothelium is an important aspect of vascular function and pathology. Simple and reliable methods for assessing the presence or absence of endothelium in vascular specimens are presented. Intravenous Evans blue dye that stains endothelial denuded vessel walls in recommended for the macroscopic visualization of endothelial injury in gross intact arterial specimens. Scanning electron microscopy (SEM) is often used for investigating microscopic endothelial injury, but the differentiation of endothelial cells from underlying vessel wall structures can be difficult. By demarcating endothelial cell borders, silver stains allow for better endothelial identification by SEM. A third technique describes assessing endothelial integrity by how well it functions and involves the selective production of endothelium derived relaxing factor. As cardiovascular surgeons become more involved in basic vascular research, a review of these techniques should be appropriate and helpful.

Animals↗
PubMed1989

Airway obstruction after autologous reimplantation of the porcine lobe.

Bronchiolitis obliterans (irreversible small airway obstruction) is a late complication of heart-lung transplantation. Chronic immune rejection is believed to be the major cause of this complication. Our hypothesis was that denervation might contribute to airway obstruction. To test this hypothesis in the absence of immune rejection, we performed a lobectomy of the upper lobe of the left lung and autologous reimplantation of the lower lobe of the left lung in 13 growing pigs. To serve as age-matched controls, six other pigs had sham left thoracotomy and nine others had a lobectomy of the upper lobe of the left lung alone. Nine to 10 weeks after operation, the animals were anesthetized and the lungs mechanically ventilated. The lobes were then isolated in vivo to measure differential transrespiratory mechanics and volumes. Dynamic compliance was significantly lower in the reimplanted lobe than it was in the contralateral right lung. This was the case after lobectomy of the upper lobe of the left lung or sham thoracotomy. Dynamic resistance was significantly higher in the reimplanted lobe than it was in the contralateral right lung and in the left lung after sham thoracotomy. Measurements of extravascular lung water, dry lobe weight, alveolar cross-sectional area, and volumetric proportions of lung parenchyma and alveolar spaces did not demonstrate abnormal structural growth after reimplantation. We conclude that lobectomy of the upper lobe of the left lung and autologous reimplantation of the left lower lobe leads to adverse changes in flow-dependent measurements of airway patency. Changes in bronchomotor regulation imposed by denervation may contribute to airway obstruction after heart-lung transplantation.

Airway Obstruction↗
PubMed1989

Assessing clamp-related vascular injuries by measurement of associated vascular dysfunction.

The development of vascular clamps requires a reliable method to quantitate clamp-related vascular injuries. The degree of vessel damage usually is estimated subjectively from photomicrographs made with scanning electron microscopy. In order to test whether the use of vascular rings to assess residual vascular function may be a better method, rabbit thoracic aortas were occluded by five types of clamps: a Fogarty softjaw bulldog, a Fogarty Hydragrip, a 6-inch Satinsky clamp, an Edslab bulldog, and a silicone vessel band. Each area of clamp injury was sectioned into a vascular ring and suspended in a tissue bath. Residual vascular function was determined by contraction in response to phenylephrine and by relaxation in response to methacholine chloride and sodium nitroprusside. Morphologic studies with use of Evans blue dye and scanning electron microscopy complemented the vascular-function studies. The Fogarty bulldog clamp was the best at preserving vascular contraction and relaxation; the more crushing Satinsky clamp was the worst. The testing of vascular rings for residual function appears to be a useful technique for objectively quantitating vascular clamp-related vascular damage.

Animals↗
PubMed1988

Morphologic and functional effects of renal cryoinjury.

Wilms' tumor presents with bilateral renal involvement in 10% of patients. With the current treatment protocols for Wilms' tumor emphasizing maximal preservation of renal parenchyma, cryosurgery may offer an alternative to bilateral tumor resections in these patients. This study was designed to examine the effects of profound cryotherapy on a significant portion of the renal parenchyma, simulating the clinical application of this technique. Eighteen New Zealand white rabbits underwent unilateral nephrectomy, with four serving as controls. The contralateral kidney in the experimental animals was subjected to cryoinjury with a liquid nitrogen probe. Needle thermocouples monitored surface temperature 1/2 cm from the margin of the probe tip and renal "core" temperature 1 cm within the renal parenchyma directly beneath the tip. The kidney was cooled until the "core" temperature reached -40 degrees C, and this was achieved with a probe temperature of -180 degrees C for an average of 11.8 min. All animals tolerated the cryoinjury well and were sacrificed in pairs at 24 and 72 hr, and 1, 2, 3, 4, and 8 weeks. Transient gross hematuria was noted in 25% of the animals and microscopic hematuria in 50%. Serum blood urea nitrogen and creatinine levels reached maximum levels at 72 hr (BUN, 92 +/- 28 mg%; Creatinine, 7.2 +/- 1 mg%) and gradually returned toward normal thereafter. The cryolesion at 24 hr resembled a hemorrhagic infarct involving 40% of the kidney. By 8 weeks this lesion had contracted to a fibrotic lesion involving 20% of the kidney by weight. The surrounding uninjured renal parenchyma underwent compensatory hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

The effect of hyperemia on spinal cord function after temporary thoracic aortic occlusion.

Nineteen mongrel dogs had 30 minutes of thoracic aortic occlusion to determine the effects that blockade of the renin-angiotensin system may have on preserving spinal cord blood flow and function during a period of temporary spinal cord ischemia. Cross-clamping of the thoracic aorta causes renal ischemia and activates the renin-angiotensin system with resulting increased production of angiotensin II. Angiotensin II is a potent peripheral constrictor and elevated levels may constrict collateral spinal cord circulation. At the time of aortic cross-clamping, 10 dogs received 100 mg/kg of MK422 (intravenous enalapril maleate), a converting enzyme inhibitor, and nine animals served as controls. The blockade of the renin-angiotensin system had no preserving effects on spinal cord flow as measured by microspheres and on spinal cord function as graded with the Tarlov scale. However, the paraplegic animals all had significantly increased lower thoracic and lumbar spinal cord flows 30 minutes after clamp release when compared with those animals that remained neurologically intact. In conclusion, marked hyperemia occurring after a period of hypoperfusion may lead to spinal cord edema and compartment syndrome with resulting paraplegia.

Animals↗
PubMed1987

A new technique for wrapping the injured spleen with polyglactin mesh.

The introduction of absorbable polyglycolic or polyglactin mesh has added a new dimension to splenic repair. Three patients with splenic disruption caused by blunt abdominal trauma underwent splenic wrapping with polyglactin mesh at the University of Virginia. The technique is described in detail. In all three instances, the spleen was saved, and postoperative nuclear medicine scans confirmed continued splenic function.

Female↗
PubMedDate not supplied

Trauma management in solid organ transplant recipients.

With trauma being common in this country and over 110,000 recent organ transplants performed, transplant recipients may become trauma victims. At present, only a few older small series of traumatized transplant patients exist. At the University of Arkansas, over the past 40 months, 12 patients with significant trauma were retrospectively identified (seven with kidney and five with combined kidney and pancreas transplants). The most common causes of trauma were car accidents and falls. All patients suffered closed skeletal fractures, and no transplanted organs were directly injured or lost. Complications included death, deep vein thrombosis, renal failure, sepsis, and pneumonia. In spite of immunosuppression and preexisting renal osteodystrophy, fractures in the surviving patients healed, with a mean follow-up of 15 months. A large series of traumatized transplant patients is presented with a review of the management of traumatic injuries for each type of organ transplant. A trauma transplant registry is needed to formulate appropriate management and follow-up.

Adolescent↗