Cyril Abrahams

Structural vs. contractile protein remodeling and myocardial stiffness in hypertrophied rat left ventricle

Left ventricular pressure overload will result in the hypertrophic growth of the myocardium and in the rat may include a remodeling of both the structural and contractile proteins. As a result, an adaptive rise in active stiffness, or the force generating capacity of the myocardium, may occur. The relative importance of structural vs. contractile protein remodeling to the hypertrophic response and active stiffness is unclear. Accordingly, we monitored the ratio of V1/V3 isomyosin and the fibrillar nature and volume fraction of myocardial collagen, together with the developed systolic stress-strain relation of the intact myocardium in the adult male Wistar rat after 8 weeks of abdominal aorta banding. In comparison to controls and for the 20% increase in left ventricular mass obtained with banding we found: (a) collagen volume fraction had increased significantly (6.2 +/- 2.0 vs. 3.6 +/- 1.0%) while the V1/V3 ratio did not change; (b) interstitial compartment remodeling included a perivascular accumulation of collagen around small intramyocardial coronary arteries and the appearance of more extensive fibrillar collagens; and (c) active stiffness increased significantly. Thus, the increase in active stiffness of the hypertrophied adult rat myocardium, seen with abdominal aorta banding, appears to be related to interstitial fibrosis and not a conversion of myosin isoforms.

Neurilemomas and salivary gland tumors of the head and neck following childhood irradiation

In a program to contact and examine 4180 individuals with a history of childhood irradiation treatment for enlarged tonsils and adenoids, the authors have discovered 29 neurilemomas, two neurofibromas, and one ganglioneuroma in the 2311 subjects who have been found. Ten of these presented as acoustic neuromas, 21 presented as cervical mass lesions, and one was found in the superior posterior mediastinum. Because of their numbers and their strict localization to the area of treatment, it was concluded that they were radiation‐induced. Analysis of the latency of these tumors indicates that they continue to occur for at least 30 years after the radiation exposure. In the same group of individuals, there have been 54 confirmed salivary gland tumors, 40 benign and 14 malignant. These tumors are also continuing to occur many years after the radiation exposure.

Salivary gland tumors after childhood radiation treatment for benign conditions of the head and neck: Dose-response relationships

We have investigated the dose-response relationships for the incidence of salivary gland tumors in a cohort of 2945 individuals who were irradiated as children between 1939-1962. Most of the patients were treated to reduce the size of their tonsils and adenoids. The mean dose to the salivary glands (+/-SD) was 4.2 +/- 1.7 Gy. Eighty-nine patients developed 91 salivary gland neoplasms; 22 had single malignancies, 64 had single benign neoplasms, 2 developed two separate benign neoplasms, and 1 developed a single neoplasm but did not have surgery. The majority (81 of 89) of the patients developed neoplasms in the parotid glands. Mucoepidermoid carcinomas were the most common malignancy and mixed (pleomorphic) adenomas were the most common benign neoplasm. For all salivary gland tumors, the excess relative risk per gray (ERR/Gy) was 0.82; however, the 95% confidence interval was wide (0.04, upper bound indeterminate). The trend was determined principally by benign tumors, as there was no dose-response relationship for salivary gland cancer, although there were too few cases to draw definitive conclusions. Overall, our study provides support for an association between salivary gland tumors and radiation exposure. Although most salivary gland tumors are benign and are usually readily detected, they may cause morbidity, and people who have been irradiated in the area should be monitored for their occurrence.

Acute eosinophilic pneumonia: A cause of reversible, severe, noninfectious respiratory failure

We report a case of acute eosinophilic pneumonia associated with adult respiratory distress syndrome in an adolescent. This entity should be considered in the differential diagnosis in previously well children and adolescents who are seen with unexplained respiratory failure and who have many eosinophils in bronchoalveolar lavage fluid. Prompt recognition of this rapidly reversible noninfectious disorder and institution of corticosteroids may be lifesaving.

Pneumonic Tularemia in a Patient with Chronic Granulomatous Disease

We report the case of a 14-year-old boy with granulomatous pneumonia caused by Francisella tularensis. In addition, an autosomal recessive form of chronic granulomatous disease was diagnosed. Both F. tularensis and chronic granulomatous disease are associated with pulmonary granulomas. To our knowledge, this is the first report of F. tularensis infection in a patient with chronic granulomatous disease. The relationship between these two processes is discussed.

Percutaneous ablation of gallstones

The purpose of this study was to determine if gallstones could be safely and effectively ablated in the pig using a proprietary percutaneous rotor-tipped catheter, the Kensey-Nash Lithotrite (KNL). All gallstones in a single human gallbladder were defined as a gallstone set. Human gallstone sets not meeting current treatment criteria for extracorporeal shock wave lithotripsy (ESWL) were placed in the gallbladder (GB) of male pigs (N = 8; 80-100 kg). A percutaneous transhepatic guide wire was put into the GB and the abdomen closed. The KNL was then introduced under fluoroscopy using the Seldinger technique and activated. Gallstone ablation was monitored by tactile and auditory feedback to the operator and by fluoroscopy. Once completed the device was withdrawn, the GB irrigated, and the 9F sheath removed. Animals were sacrificed immediately (Group 1, N = 4) and at 28 +/- 5 days (Group 2, N = 4). Gallstones were ablated in 26 +/- 8 min. No pig had significant hemorrhage, GB perforation, or pancreatitis. One acute animal had stone fragments greater than 2 mm in the gallbladder. No other animals had any fragments greater than 1 mm present in the GB, cystic duct, common duct, ampulla, or duodenum. Histologic examination of the GB showed acute hemorrhagic mucosal injury in Group 1 and extensive mucosal regeneration with some stone fragment granulomata and mural fibrosis in Group 2. We conclude that percutaneous gallstone ablation with the KNL is safe and effective in this short-term pig model and appears to be a safe procedure for gallstone ablation. Long-term safety and effectiveness remain to be demonstrated. This device should be useful for treatment of symptomatic gallstones in patients not treatable by ESWL.