Radiation dosimetry of iodine-123 HEAT, an alpha-1 receptor imaging agent

Biologic distribution data in the rat were obtained for the alpha-1 adrenoceptor imaging agent (+/-) 2-[beta-(iodo-4-hydroxyphenyl)ethylaminomethyl]tetralone (HEAT) labeled with [125I]. The major excretory routes were through the liver (67%) and the kidney (33%). Internal radiation absorbed dose estimates to nine source organs, total body, the GI tract, gonads, and red bone marrow were calculated for the human using the physical decay data for [123I]. The critical organ was found to be the lower large intestine, receiving 1.1 rad per mCi of [123I]HEAT administered. The total-body dose was found to be 58 mrad per mCi.     

Ocular infections associated with Eikenella corrodens

Eikenella corrodens is a gram-negative, facultative rod-shaped anaerobe that colonizes the human mouth, nasopharynx, gut, and genitourinary tract. We treated a corneal ulcer from which E. corrodens was the primary isolate in an otherwise healthy man. We treated another patient who had recurrent bacterial endophthalmitis from which Eikenella was identified in mixed culture. Named for its ability to form pits in agar, the corroding bacillus is gaining recognition for its role in head and neck infections. Certain E. corrodens strains are mobile on moist surfaces and elaborate an endotoxin, which may destroy human tissues directly and indirectly by means of the immune system. The organism is usually resistant to aminoglycosides and penicillinase-resistant penicillins yet is susceptible to penicillin and some cephalosporins.     

In vivo binding in rat brain and radiopharmaceutical preparation of radioiodinated HEAT, an alpha-1 adrenoceptor ligand

In vivo binding of [125I]-2-[beta-(3-iodo-4-hydroxyphenyl)ethylaminomethyl tetralone) ([125I]HEAT) to alpha-1 adrenoceptors in the rat brain was determined over 4 hr. Uptake in the thalamus and frontal cortex was approximately 0.1% injected dose per gram tissue. Thalamus/cerebellum ratios of 10:1 and frontal cortex/cerebellum ratios of 5:1 were found at 4 hr. Pretreatment with prazosin, an alpha-1 antagonist, completely inhibited the accumulation of [125I]HEAT in thalamus and frontal cortex; yet uptake of radioactivity was not significantly affected by antagonists and agonists for other receptors classes (propranolol, beta-1; apomorphine, D-1; spiperone, D-2). Binding of [125I]HEAT is saturable. At 4 hr, [125I]HEAT or [123I]HEAT was shown to be the only radioactive material in rat thalamus and frontal cortex. Iodine-123 HEAT and [125I]HEAT were synthesized as radiopharmaceuticals within 3 hr in 99% radiochemical purity.     

Resource-based relative values for invasive procedures performed by eight surgical specialties

We surveyed approximately 850 physicians in eight surgical specialties to investigate physicians' work in performing invasive services. Building on our analysis of physician work, we developed a relative value scale of physicians' services based on resource costs. First, we found that physician charges are not set in proportion to the resources required to perform a given procedure: there is a threefold variation, across hospital-based invasive procedures, in the ratio of charges to resource-based relative values. Second, for most procedures, the preoperative and postoperative periods represent 60% to 75% of a physician's total service time, but only 35% to 50% of the total service work. Lastly, intraoperative work per unit of time varies greatly. Work per minute for invasive procedures is two to three times that of medical office visits and is strikingly greater for some specialties. The Resource-Based Relative Value Scale, at a minimum, represents a useful tool for payers to identify procedures with potentially aberrant charges and also offers unique insights into the nature of physicians' work.