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Biomedical subjects

V A Starnes

Publications and source records attributed to V A Starnes.

At least 145 records · Page 8Linked to original sources
PubMed1984

Barrett's esophagus. A surgical entity.

During a ten-year period, endoscopy demonstrated acid-peptic esophagitis in 439 patients. Forty of these patients (9.1%) had Barrett's esophagus. Adenocarcinoma was present in the columnar epithelium in 15 (37.5%) of the patients with Barrett's esophagus. Hiatal hernias, with symptoms of heartburn, dysphagia, stricture, and ulceration, were found in more than 75% of the patients with Barrett's esophagus. We developed a treatment algorithm. Patients with symptomatic reflux esophagitis should undergo endoscopy with biopsy. If Barrett's esophagus is diagnosed, an antireflux procedure should be performed, preferably a proximal gastric vagotomy with Nissen's fundoplication. Follow-up examination by endoscopy with biopsy and cytology should be performed every six months. Indications for early esophagectomy include progression of cellular dysplasia, carcinoma in situ, and a non-healing Barrett's ulcer following an antireflux procedure. Our data support an aggressive surgical treatment of patients with Barrett's esophagus.

Adenocarcinoma↗
PubMed1984

Longitudinal pancreaticojejunostomy in chronic relapsing pancreatitis with onset in childhood.

Despite the rarity of chronic relapsing pancreatitis in children, in the last 15 years at Vanderbilt University Medical Center and its Children's Hospital we have used longitudinal pancreaticojejunostomy in treatment of eight patients whose symptoms began in childhood. Duration of symptoms ranged from 2 to 36 years. Seven of the eight patients had hereditary pancreatitis. Recurrent epigastric pain was characteristic and serum amylase was elevated in all patients on admission or shortly thereafter. Demonstration of an obstructed dilated pancreatic duct in all and stones in seven of eight patients by operative pancreatography in three early patients and by endoscopic retrograde cholangiopancreatography (ERCP) in five others established the therapeutic problem and facilitated treatment by removal of stones and longitudinal pancreaticojejunostomy. Results were uniformly excellent, both in the early postoperative period and in long-range follow-ups. Early diagnosis and early surgical drainage of the obstructed pancreatic duct by longitudinal pancreaticojejunostomy are desirable objectives in chronic relapsing pancreatitis with onset in childhood.

Adolescent↗
PubMed1984

Comparative effects of verapamil, nifedipine, and diltiazem on contractile function in the isolated immature and adult rabbit heart.

The effects of postnatal development on the systolic and diastolic responses to pharmacologic blockade of the slow inward calcium current were investigated in blood-perfused hearts isolated from immature (14-21-day-old) and adult rabbits. Isovolumic left ventricular developed pressure, resting pressure, and maximal rate of pressure development (+dP/dt) at cumulative doses of either verapamil, nifedipine, or diltiazem were determined by means of an intracavitary balloon. Myocardial contractile function in the immature heart was more sensitive to pharmacologic blockade of the slow inward calcium current than is the adult heart. Doses of verapamil, or nifedipine, that comparably reduced pretreatment developed pressure and +dP/dt were approximately 10-fold less in immature as compared to the adult heart. The dose of diltiazem which reduced developed pressure and dP/dt by 50% was 3-fold less in immature as compared to the adult heart. Verapamil and nifedipine decreased resting pressure in the adult but not in the immature heart. Conversely, diltiazem decreased resting pressure in the immature while not affecting resting pressure in adult hearts. Thus, postnatal cardiac development affects both the systolic and diastolic responses to calcium channel blockade. In addition, diltiazem appears to be qualitatively and quantitatively different from verapamil and nifedipine with respect to the age-related cardiac effects of calcium channel blockade.

Aging↗
PubMed1983

Kinetics and imaging of indium-11-labeled autologous platelets in experimental myocardial infarction.

The kinetics of accumulation and the external imaging patterns of indium-111-labeled platelets infused in a dog model of left anterior descending coronary artery occlusion with reperfusion were studied. The effects of infarct age and regional residual myocardial blood flow upon platelet accumulation were quantified, and the capacity of indium-111 platelets to image the experimental infarction was evaluated qualitatively. The endocardial accumulation of indium-111 platelets occurred primarily in infarct zones with residual blood flow less than 0.6 times normal and was maximal (24.98 +/- 2.76 times normal) in the lowest blood flow zone (less than 0.1 times normal). Indium-111 platelet accumulation in the epicardium occurred in the regions with blood flow less than 0.6 times normal and was maximal (17.83 +/- 1.20 times normal) in the lowest blood flow zone (less than 0.1 times normal). The maximal endocardial and epicardial platelet accumulation occurred 24 hours after reperfusion and was significantly decreased at 48 hours. In vivo cardiac images revealed discrete areas of increased myocardial radioactivity uptake in the anterior wall of dogs 24 hours after reperfusion. All images 48 hours after reperfusion were negative. Thus, in the experimental setting, indium-111 platelets allow quantification of platelet accumulation after myocardial infarction at a tissue level and provide a noninvasive means of in vivo imaging of reperfused infarcted myocardium.

Animals↗
PubMed1982

Functional and metabolic preservation of the immature myocardium with verapamil following global ischemia.

This study investigated the effects of the calcium antagonist verapamil on the functional and biochemical recovery of the immature heart following 30 minutes of normothermic ischemia. Verapamil (0.2 mg per kilogram of body weight) was infused into the aortic root in 5 puppies (8 to 10 weeks of age) prior to cardiopulmonary bypass. Five additional puppies received saline solution as a control. Left ventricular developed pressure, rate of rise of left ventricular pressure (dP/dt), left ventricular endsystolic pressure-diameter relationship (emax), compliance, and water content were assessed before and after bypass. Serial myocardial biopsies for adenosine triphosphate (ATP) and creatine phosphate were obtained. Puppies pretreated with verapamil recovered more than 80% of the preischemic left ventricular developed pressure, dP/dt, and emax in contrast to 50% recovery in the controls (p less than 0.05). The ATP content declined 40% during the interval of ischemia in the control puppies, versus 14.6% in the verapamil-treated puppies (p less than 0.05). Myocardial compliance was preserved in the verapamil-treated puppies and was associated with significantly less myocardial water content (78% versus 80.1% in the controls)(p less than 0.01). This study demonstrates the protective effects of verapamil on the immature heart during ischemic arrest. These results suggest that verapamil may be a useful adjunct to current methods of protecting the infant heart during cardiopulmonary bypass.

Adenosine Triphosphate↗
PubMedDate not supplied

Administration of prostacyclin prevents ventricular fibrillation following coronary occlusion in conscious dogs.

The effects of prostacyclin (PGI2) on ventricular arrhythmias following 20 min of coronary occlusion and release were studied in 34 conscious dogs. We administered PGI2 at 100 ng/kg/min and did not observe significant changes in heart rate, blood pressure, or systemic vascular resistance. During the control period, heart rate was 97 +/- 30 (mean +/- SEM) vs. 99 +/- 28 in the PGI2-treated group. Mean arterial pressure was 115 +/- 26 mm Hg and 109 +/- 10 mm Hg in the control and PGI2 groups, respectively. Systemic vascular resistance declined minimally from 2,985 +/- 221 dyn . s . cm-5 to 2,484 +/- 135 dyn . s . cm-5 during the PGI2 infusion (p = NS). Following coronary occlusion, the frequency of ventricular fibrillation was reduced from 53% (9/17) in the control group to 6% (1/17) in the PGI2 group (p less than 0.01). Overall 80-min postinfarction survival was 64% in the group receiving PGI2 infusion compared to 24% in the control group (p less than 0.05). The effects of PGI2 in preventing ventricular fibrillation following acute coronary occlusion can be ascribed to a direct action of this prostaglandin on the myocardium, rather than to an indirect effect due to a reduction in systemic vascular resistance.

Animals↗
PubMedDate not supplied

Assessment of cardiac allograft rejection with electrophysiology of the conduction system and histopathology of the ventricle.

Correlation between the effective refractory period of the conduction system and the histopathologic grade of the ventricle was examined in the rat cardiac allograft during acute rejection. Lewis rats were recipients of intraabdominal heart grafts from brown Norway rats (allogeneic group, n = 42) or Lewis rats (syngeneic group, n = 15). No immunosuppressant was given. The effective refractory period of the conduction system was measured by the programmed atrial extrastimulus method (basic cycle length, 150 msec) just before the time of death. Specimens of the transplanted hearts were examined histopathologically and the histopathologic grade of rejection was scored according to the standardized grading system of the International Society for Heart and Lung Transplantation. The effective refractory period of the allogeneic heart was significantly longer starting on the third day after transplantation (p less than 0.01). The effective refractory period of the allogeneic heart was more prolonged as the severity of rejection increased. The correlation between the effective refractory period (Y) and the histopathologic grade (X) of the allogeneic group was statistically significant (r = 0.955; Y = 10.3X + 81.0; p less than 0.01). The effective refractory period of all syngeneic hearts and allogeneic hearts of postoperative day 1 and 2 were statistically equivalent to the period of native rat hearts (81.0 +/- 2.0 msec; n = 6). The histopathologic grade of the conduction system was the same as that of the ventricle. We conclude that the effective refractory period of the conduction system could be a useful measure to predict the histopathologic grade of cardiac allograft rejection.

Abdomen↗
PubMedDate not supplied

Selective T-cell depletion with Ox-38 anti-CD4 monoclonal antibody prevents cardiac allograft rejection in rats.

New monoclonal antibodies directed to membrane molecules unique to lymphocyte subsets have provided the means to alter the immune response to alloantigens in a more selective fashion. This investigation demonstrates that monoclonal antibody-induced depletion of CD4 helper/inducer T lymphocytes before transplantation of a fully mismatched heart allograft allows permanent engraftment in rats without further immunosuppression. Five adult male ACI (RT1a) rats received cell-depleting doses of the mouse anti-rat CD4 monoclonal antibody, MRC Ox-38, for 1 month before undergoing heterotopic abdominal heart transplantation. No other immunosuppression was administered, and immunotherapy was discontinued the day of transplantation. After all five Lewis rat (RT1(1)) hearts were maintained free of rejection for more than 3 months, a second heterotopic transplant was performed, this time to the femoral vessels, using either fresh Lewis heart allografts (n = 3) or third-party, Brown-Norway (RT1n) hearts (n = 2). Histologic evaluation was performed 3 weeks later and revealed severe rejection of the femoral Brown-Norway grafts with no evidence of rejection in any of the femoral or original abdominal Lewis grafts. These results suggested that limited, pretransplant anti-CD4 immunotherapy allowed permanent engraftment of fully mismatched cardiac allografts in rats and conferred donor-specific unresponsiveness.

Abdomen↗
PubMedDate not supplied

Clinical significance of hyperbilirubinemia in patients with pulmonary hypertension undergoing heart-lung transplantation.

Hyperbilirubinemia is commonly observed in long-standing pulmonary hypertension and is thought to be the result of chronic right ventricular failure and subsequent liver congestion. To evaluate the clinical significance of preoperative hyperbilirubinemia, we reviewed the cases of 62 patients with pulmonary hypertension (31 primary and 31 Eisenmenger's syndrome) who underwent heart-lung transplantation between 1981 and 1990 at Stanford. Bilirubin levels higher than 1.0 mg/dl were noted in 58% of patients, and bilirubin levels higher than 2.0 mg/dl were noted in 23% of patients. Indirect hyperbilirubinemia accounted for 66% to 87% of the total bilirubin and tended to fluctuate with diuretic therapy. It was associated with polycythemia, reticulocytosis, and mild elevations of liver enzymes. Early postoperative mortality in patients with total bilirubin levels greater than 2.1 mg/dl, bilirubin levels greater than 1 mg/dl but less than 2.0 mg/dl, and levels less than 1 mg/dl was 58%, 27%, and 16%, respectively (p less than 0.05). In those with high bilirubin levels, four patients had severe hemorrhage as part of their terminal event. Cardiac cirrhosis was found at autopsy in 75% of the early deaths of patients with high bilirubin. We conclude that hyperbilirubinemia is a late manifestation of pulmonary hypertension. The mechanism of hyperbilirubinemia is probably the result of the combination of increased hemolysis and decreased uptake by the chronically congested liver. Patients with pulmonary hypertension and hyperbilirubinemia appear to be at greater surgical risk during heart-lung transplantation.

Adult↗
PubMedDate not supplied

Nontuberculous mycobacterial infections in heart transplant recipients: a seventeen-year experience.

A retrospective review was undertaken to determine the clinical features, outcome, and impact on survival of nontuberculous mycobacterial infections in 14 (of 502) heart transplant recipients. The prevalence of these infections was significantly higher (p less than 0.05) during the precyclosporine than during the cyclosporine era. The mean interval from transplantation to diagnosis was 3.5 +/- 0.7 years (+/- SEM). The 14 patients had a higher (p less than 0.05) linearized rejection rate than did other transplant patients during postoperative years 1, 2, and 4 to 6, and had received 7.3 +/- 2 gm of methylprednisolone as bolus treatment of rejection before diagnosis. Eight patients were initially seen with disseminated disease, four had localized pulmonary infection, one had subcutaneous infection in the previous site of a left ventricular assist device, and in one the organism was cultured from a fluid collection adjacent to a hip prosthesis. Twelve patients were first given 3 +/- 1 antimycobacterial drugs; the infections were usually controlled, but in 75% of patients the therapeutic regimen was prematurely stopped or altered because of drug toxicity. Mycobacterial infection was a contributory cause of death in only one patient. Actuarial survival in the 14 patients was not significantly different from the entire transplant population at 4 to 7 years. We conclude that nontuberculous mycobacterial infections occur late after heart transplantation, that drug treatment is usually successful (although difficult), and that long-term survival is not adversely affected if the infection is successfully controlled.

Adult↗
PubMedDate not supplied

Cytomegalovirus infection is associated with cardiac allograft rejection and atherosclerosis.

We studied the effects of cytomegalovirus (CMV) infection on 301 cardiac transplant recipients who were treated during the cyclosporine era of immunosuppression (1980 to the present). These patients received varying combinations of cyclosporine, azathioprine, prednisone, rabbit antithymocyte globulin, and OKT3 as their immunosuppressive therapy. Two hundred ten patients were free of CMV infection (non-CMV group). During the same period CMV infection developed in 91 patients, as manifested by a fourfold IgG serologic titer rise, demonstration of CMV inclusion bodies in tissue, or positive cultures for the virus (CMV group). The rate of graft rejection was significantly higher in the CMV group. Graft atherosclerosis was significantly more severe in the CMV group as judged by angiographic criteria or by pathologic study. Patient survival rates were significantly lower in the CMV group. Death caused by graft atherosclerosis was significantly more common among patients in the CMV group. Finally, the graft loss rate (from either death or retransplantation for atherosclerosis) was significantly greater in the CMV group. These data demonstrate that CMV infection in cardiac transplant recipients is associated with more frequent rejection, graft atherosclerosis, and death.

Adult↗
PubMedDate not supplied

Heart transplantation in children.

Heart transplantation in children is being performed with increasing frequency. As experience has accrued, problems of rejection, graft atherosclerosis, and growth have been noted. Seventeen children (seven boys and 10 girls) between the ages of 5 months and 14 years have undergone heart transplantation since 1981. The preoperative diagnosis was cardiomyopathy in 13 children, congenital heart disease in two, and endocardial fibroelastosis in two. Immunosuppressive therapy has included a tapering schedule of cyclosporine, azathioprine, and prednisone. There are 13 children alive, with four hospital deaths (two of infection, one of rejection, and one of graft failure). Rejection occurs as frequently in children as in adults. Two children have undergone retransplantation for rejection. Long-term hemodynamics are normal. Growth has been delayed in two of five children who are younger than age 10 years. Kidney function remains stable. Rehabilitation is 100% among the discharged patients. Heart transplantation in children represents an effective therapeutic modality. Heart transplantation in the young has emphasized morbidity caused by current immunosuppressive agents.

Adolescent↗
PubMedDate not supplied

Comparison of cyclosporin A and G with and without azathioprine regarding immunosuppressive efficacy, toxicity, and pharmacokinetics in Lewis rats.

Cyclosporin A-associated nephrotoxicity has precipitated the need to develop new immunosuppressive protocols or agents that have a higher therapeutic index than cyclosporin A. A new immunosuppressive agent, cyclosporin G or norvaline (Nva-2) cyclosporine, has been shown to be potent. The rat heterotopic transplant model (ACI to Lewis) and Lewis rats that had no operation were used to compare cyclosporin G with cyclosporin A (5 mg/kg/day per gavage) with and without azathioprine (5 to 10 mg/kg/day, intraperitoneally) in terms of immunosuppressive efficacy (graft survival), toxicity (mortality, renal histopathology, and serum creatinine and blood urea nitrogen values), and pharmacokinetics (trough whole blood cyclosporine levels as measured by radioimmunoassay on days 14 and 28 of treatment). In this model no statistically significant difference in immunosuppression was shown between the two cyclosporins both with and without azathioprine. Cyclosporin G, however, was associated with significantly less mortality when combination therapy with azathioprine was used. Both cyclosporins were associated with normal serum creatinine values and little histopathologic evidence of nephrotoxicity, except juxtaglomerular apparatus hyperplasia. Comparable cyclosporine levels were achieved when cyclosporin A or G was used as the sole immunosuppressive agent, but significantly higher cyclosporine levels were shown with cyclosporin A than with cyclosporin G when combination therapy with azathioprine was used. Further studies in humans are needed to evaluate whether cyclosporin G will be a clinically useful immunosuppressive agent either alone or combined with other immunosuppressive modalities.

Animals↗
PubMedDate not supplied

Comparison of cardiac rejection in heart and heart-lung transplantation.

Cardiac biopsy remains the principal tool for diagnosis of rejection in heart and heart-lung transplantation. In rare instances pulmonary rejection may occur without cardiac rejection, but the overall incidence of cardiac rejection may be less with heart-lung transplantation than with heart transplantation. During the 6 months from March to September 1986, 40 heart transplantations and nine heart-lung transplantations were performed. Heart transplant patients received cyclosporine (8 to 10 mg/kg/day), azathioprine (1 to 2 mg/kg/day), and prednisone (0.8 mg/kg/day, with tapering). Heart-lung transplant patients received cyclosporine and azathioprine in the same dosages, but steroids were withheld for 3 weeks. Heart-lung transplant patients received three postoperative dosages of rabbit antithymocyte globulin (200 mg intramuscularly). There were five early deaths in the heart transplant group, four from infection and one from cerebrovascular accident. Since the initial rejection analysis presented here, one additional heart transplant patient died from rejection (241 days), and one heart-lung transplant patient died from infection (99 days). Cyclosporine levels were determined by radioimmunoassay, and cardiac rejection was diagnosed by serial endomyocardial biopsy. Early cardiac rejection is notably less common after heart-lung transplantation than after heart transplantation. Although the prophylactic antithymocyte globulin given in heart-lung transplantation may be important in this regard, rejection is probably inherently less common after heart-lung transplantation.

Adult↗