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Biomedical subjects

F A Baciewicz

Publications and source records attributed to F A Baciewicz.

At least 19 recordsLinked to original sources
PubMed1995

Chronic changes of end-systolic pressure-volume relationship after regional myocardial infarction.

The chronic changes of the end-systolic pressure-volume relationship (ESPVR) after regional myocardial infarction were evaluated in a sheep model. Pressure-volume area (PVA) obtained from the pressure-volume diagram and left ventricular oxygen consumption (LVO2) were studied. The regional myocardial infarction was created by ligating distal branches of the left coronary artery. ESPVR was obtained using a conductance catheter during transient inferior vena cava occlusion. Measurements were performed at baseline (n = 13), 1 hour (n = 8), 3 months (n = 9), and 6 months (n = 4) after infarction. Ees, the slope of the ESPVR did not change at 1 hour after infarction and remained the same at 3-month and 6-month measurements (baseline 2.26 +/- 1.24 mmHg/mL, 1 hour 2.71 +/- 1.06, 3 months 3.46 +/- 1.51, 6 months 2.45 +/- 0.64, NS). Because of the ventricular dilatation, which was demonstrated as an increase in changes of end-systolic volume (Ves) correlating with the time course after infarction (y = -3.21 + 0.12x, r = 0.454, p < 0.05), V0, the volume intercept of the ESPVR increased at 1 hour after the infarction, and showed a tendency to increase at 3 months and 6 months after the infarction (baseline -18.0 +/- 22.5 mL; 1 hour -0.9 +/- 11.6; 3 months 5.4 +/- 10.9, 6 months 9.2 +/- 23.1, baseline vs 3 months p < 0.05, baseline vs 6 months p < 0.05). PVA and LVO2 were unchanged over time after infarction (PVA: baseline 2097 +/- 1526 mmHg/mL per 100 g-1; 1 hour 1771 +/- 699; 3 months 2483 +/- 1086; 6 months 1,608 +/- 1,010, NS), (LVO2: baseline 40.6 +/- 13.1 x 10(-3) mL/100 g-1 per beat-1; 1 hour 42.9 +/- 9.7; 3 months 35.0 +/- 8.6; 6 months 31.2 +/- 18.1, NS). Chronic regional infarction in the sheep model did not affect Ees over 6 months, but significantly increased V0 after the increase in the acute phase. PVA and LVO2 were not affected by this regional infarction either acutely or over 6 months.

Animals↗
PubMed1994

Detection of canine allograft lung rejection by pulmonary lymphoscintigraphy.

We previously demonstrated that lymphoscintigraphy could be used to study pulmonary lymphatic flow. Radiocolloids, high-molecular-weight proteins tagged with radioactive markers, are injected percutaneously in the periphery of the lung. These molecules enter the lymph, are transported via lymphatic channels, and concentrate in the tributary hilar and mediastinal lymph nodes, where they can be visualized by nuclear scan. The goal of this study was to determine whether pulmonary lymphoscintigraphy could be used to detect allograft rejection after lung transplantation. Thirteen mongrel dogs underwent left lung allotransplantation. Cyclosporine 15 mg/kg per day and azathioprine 1 mg/kg per day were given orally for postoperative immunosuppression. Lymphoscintigraphic studies were obtained 1 week after the operation and then at weekly intervals. In five dogs (group A), immunosuppression was continued until the animal died or was put to death 6 weeks later. Lymphoscintigraphy demonstrated reestablishment of lymphatic drainage between the lung graft and the mediastinum in all the animals 2 to 4 weeks after transplantation. In eight dogs (group B), immunosuppression was discontinued after reestablishment of graft lymphatic drainage was documented by two consecutive lymphoscintigraphic studies. The dogs continued to be studied with weekly scans. In group B, lymphatic drainage from the lung graft to the mediastinum disappeared 1 to 4 weeks after immunosuppression was stopped. Rejection was diagnosed clinically and confirmed histologically with open lung biopsies and/or autopsies in all animals. This study shows that canine allograft lung rejection is associated with disappearance of lymphatic drainage from lung graft to mediastinum, which can be documented by pulmonary lymphoscintigraphy, a minimally invasive technique that can be easily repeated. Pulmonary lymphoscintigraphy may be useful for early detection of lung allograft rejection.

Acute Disease↗
PubMed1993

Ketoconazole and fluconazole drug interactions.

This article reviews potential drug interactions that exist between ketoconazole or fluconazole and other drugs. English-language data sources included human subjects' computerized databases and published indexes. Case reports and studies demonstrate decreased dosage requirements of cyclosporine sodium, methylprednisolone sodium succinate, and possibly anticoagulants and phenytoin after ketoconazole or fluconazole administration, suggesting hepatic enzyme inhibition. Increased dosage requirements of ketoconazole are necessary after rifampin administration, suggesting rifampin's induction of hepatic microsomal enzymes. Possibly a similar effect may occur with concomitant fluconazole and rifampin. The effect of ketoconazole administration on prednisolone sodium phosphate and theophylline warrants further study. Fluconazole, a more selective agent for fungal P-450, seems to be of less concern regarding the potential for drug interactions than ketoconazole.

Drug Interactions↗
PubMed1993

Reestablishment of lymphatic drainage after canine lung transplantation.

The technique of pulmonary lymphoscintigraphy was used to evaluate pulmonary lymphatic flow and to assess reestablishment of lymphatic drainage after lung transplantation. A first group of six control dogs underwent percutaneous transthoracic injection of a radiocolloid into the periphery of the left upper and lower lobes. Radiocolloids are large molecules tagged with radioisotopes that are absorbed only through lymph and are concentrated in tributary lymph nodes. Twenty-four hours after injection the dogs underwent scintigraphic studies of the chest and upper part of the abdomen. Mediastinal lymph nodes were visualized in all animals. A second group of four dogs underwent partial reimplantation of the native left lung, with interruption of all lymphatic connections between the lung and mediastinum. Lymphoscintigraphic studies of the left lung were obtained on the third postoperative day and then weekly for 4 weeks. Three of the four dogs in this group did not have visible mediastinal nodes 3 days after the operation. Nodes were visualized in all animals at 1 week and at all following studies. A third group of five dogs were subjected to left lung allotransplantation by means of standard surgical techniques, as well as immunosuppression. The animals were studied with radiocolloid injections and lung lymphoscintigraphy at weekly intervals for 6 weeks. Mediastinal nodes were visualized for the first time 2 to 4 weeks after the operation and at every subsequent study. We conclude that lung lymphoscintigraphy is a reliable technique for the study of pulmonary lymphatic flow. This experiment demonstrates that lymphatic drainage after lung transplantation is reestablished as early as the second postoperative week.

Animals↗
PubMed1991

Pharmacokinetics and toxicity of isolated perfusion of lung with doxorubicin.

The treatment of pulmonary metastases from soft tissue sarcomas with chemotherapy has an overall response rate of less than 30%, and the majority of these responses are short lived. It is postulated that increased drug delivery to the pulmonary metastases may improve the outcome of these patients. An isolated perfusion system would have the ability of delivering increased levels of drug to target tissue without the systemic toxic effect of the drug. The purpose of this study was to establish the pharmacokinetics of doxorubicin delivery, lung toxicity, and the ideal dose for clinical application in an in vivo isolated perfusion model. Our results suggest that normothermic isolated perfusion of the lung with doxorubicin using a dose level up to 6 micrograms/ml in the perfusate can be accomplished without histologic lung injury, systemic toxicity, or adverse clinical outcome. Perfusate concentration of greater than 7 micrograms/ml caused significant histologic injury and adverse clinical outcome without systemic toxicity. The technique may be utilized in selective settings to improve treatment in mesenchymal tumors metastatic to the lung.

Animals↗
PubMed1990

Influence of clerkship structure and timing on individual student performance.

Student oral and written surgical clerkship performances may be related to the clerkship structure and the time of year the students rotate through the clerkship. The influence of calendar block, hospital site (university hospital, affiliated private tertiary-care hospital, and rural preceptor experience), and the mix of general surgical versus subspeciality rotations on oral and written student surgery clerkship scores was analyzed. Multivariate analysis of variance revealed significant differences in score for calendar block (p = 0.02) only; this difference resided in the written examination. The various combinations of rotations were not different from one another in terms of measured outcome.

Clinical Clerkship↗
PubMed1990

Labetalol and MRI as initial medical and diagnostic modalities in a marfanoid patient with expanding ascending aortic aneurysm.

Marfan syndrome is a hereditable disorder of connective tissue that causes several distinct cardiovascular abnormalities, including aortic regurgitation, dissection, and aneurysm. These cardiac manifestations can be identified with echocardiography, computer tomography, and angiography. Standard treatment of an acute hypertensive crisis in Marfan syndrome uses propranolol and sodium nitroprusside. This patient with Marfan syndrome whose case is reported herein presented with chest pain, hypertensive crisis, and aortic insufficiency; labetalol was used successfully to treat the acute hypertensive crisis and magnetic resonance imaging (MRI) was used to differentiate between aortic dissection and an expanding aortic aneurysm. This report is unique in that labetalol was used to control the hypertensive crisis in Marfan syndrome and MRI was used as the initial diagnostic modality in an emergency setting.

Acute Disease↗
PubMed1990

Do first- and second-year preclinical course scores predict student performance during the surgical clerkship?

The study proposed to determine if a preclinical basic science index comprised of anatomy, behavioral medicine, biochemistry, microbiology, pathology, pharmacology, and physiology courses or any one of these basic science courses would predict student performance during surgical clerkship. The basic science index demonstrated a correlation of 0.55 and 0.35 with the individual student's written and oral clerkship scores, respectively. A stepwise multiple regression using a backward stepping algorithm was applied; the dependent variables were oral and written clerkship scores, and the independent variables were the basic science courses. Microbiology, pathology, and physiology course scores were predictors of written score (R = 0.60). Pathology course scores were the sole predictor of oral score (R = 0.43). Medical student basic science performance was not a strong forecaster of performance on the surgical clerkship. The pathology basic science score was the only consistent predictor of performance on the written and oral evaluations given at the end of the clerkship.

Clinical Clerkship↗
PubMed1989

Effect of cimetidine and ranitidine on cardiovascular drugs.

A compilation of drug interactions between H2 antagonists and cardiovascular drugs is found in Table I. Cimetidine's potency, lipophilicity, and affinity for binding to the P-450 cytochrome system can probably be attributed to the drug interactions that have been identified with the H2 antagonists. The mechanism for most cimetidine drug interactions is inhibition of hepatic metabolism. There is conflicting evidence regarding significance of altered liver blood flow for both cimetidine and ranitidine and their influence on other agents. Cimetidine may increase propranolol's blood concentrations and potentiate beta blocking effects through inhibition of hepatic microsomal enzymes and possibly through reduction of hepatic blood flow. Ranitidine has no effect on propranolol. Cimetidine, when administered concurrently with metoprolol, could possibly cause an increase in plasma metoprolol concentrations or bioavailability through inhibition of hepatic P-450 metabolizing enzymes. No effect of cimetidine on metoprolol pharmacodynamics was evident. Ranitidine has no effect on metoprolol pharmacokinetics or pharmacodynamics. Neither H2 antagonist altered the kinetics or physiologic effects of atenolol. Atenolol is the drug of choice in patients receiving H2 antagonists, since no interaction has been observed. Metoprolol could probably be used safely in most patients, as no change in pharmacodynamics has been evident. Concurrent administration of cimetidine and nifedipine may result in alterations in heart rate and blood pressure. The mechanism is inhibition of oxidative liver metabolism. Ranitidine has no effect on nifedipine. Studies are needed to investigate the interaction between the H2 antagonists and diltiazem or verapamil. Cimetidine, given concomitantly with lidocaine, may increase lidocaine concentrations and clinical symptoms of lidocaine toxicity. The mechanism involved is probably a reduction in oxidative drug metabolism or liver blood flow. Ranitidine has no significant effects on lidocaine pharmacokinetics. Cimetidine may increase quinidine levels and symptoms of quinidine toxicity. Additionally, enhanced arrhythmic effects may be observed. The interaction probably caused by an inhibition of hepatic drug metabolism of quinidine by cimetidine would be most significant in patients with liver disease and in the elderly. Ranitidine may enhance quinidine's arrhythmic effect. Cimetidine can possibly increase procainamide and NAPA serum concentrations, especially in the elderly and in patients with renal dysfunction, predisposing them to adverse side effects. The interaction is mediated by a reduction of tubular secretion of procainamide and NAPA.

Cardiovascular Agents↗
PubMed1989

Cyclosporine pharmacokinetic drug interactions.

Cyclosporine (CyA) is commonly prescribed as an immunosuppressive to prevent rejection of organ transplants. Numerous pharmacokinetic drug interactions of potential clinical significance exist because other drugs may induce or inhibit the metabolism of CyA. Case reports and studies demonstrate that rifampin, phenytoin, phenobarbital, and carbamazepine may induce the hepatic metabolism of CyA, causing decreased CyA concentrations. Graft rejection through inadequate immunosuppression may be associated with subtherapeutic or decreased CyA levels. Erythromycin, ketoconazole, calcium channel blockers, and sex hormones appear to inhibit CyA metabolism, causing increased CyA concentrations. Signs and symptoms of renal, hepatic, or neurotoxicity may be evident with increased or toxic CyA levels. Mutual inhibition of metabolism occurs between CyA and corticosteroids. Intravenous sulphadimidine and trimethoprim may cause decreased CyA concentrations by an unknown mechanism.

Adrenal Cortex Hormones↗
PubMed1989

Congenital heart disease in Down's syndrome patients: a decade of surgical experience.

Patients with Down's syndrome represent a significant subset of patients with congenital heart disease. Fifty-five patients with Down's syndrome have undergone surgical treatment for congenital heart disease at our institution in the past decade. Twenty-six had atrioventricular canal, 11 had ventricular septal defect, 7 had secundum atrial septal defect, 7 had tetralogy of Fallot, 3 had primum atrial septal defect and 1 patient had double outlet right ventricle. The thirty day mortality following operative intervention was 16.4%. Mortality was highest for tetralogy of Fallot followed by atrioventricular canal and ventricular septal defect. Long term mortality for all lesions was 27.3% over our follow-up period which averaged 33 months. Thirty day mortality compared similarly to previous reports of surgically treated Down's syndrome patients. When compared to our patients without Down's syndrome, the Down's population did not exhibit an increased risk for surgical treatment of congenital heart disease.

Adolescent↗
PubMed1988

Vocal cord paralysis in premature infants undergoing ductal closure.

A series of 106 consecutive ductal closures in premature infants was reviewed to assess the incidence of left vocal cord paralysis. To our knowledge, this syndrome is described for the first time in premature infants. In our experience, it is a relatively benign complication that completely resolves clinically in several weeks. This complication occurred in 5.2% of patients closed by suture ligature and in none of those closed by a surgical clip. Although the series is too small for this difference to be statistically significant, we believe it strongly favors the use of the clip, with less dissection.

Ductus Arteriosus, Patent↗