A comparison of tablets with oral suspension formulation of dipyridamole in thallium myocardial imaging.

Dipyridamole stress thallium imaging has been widely employed to diagnose and assess the extent of coronary heart disease in patients who cannot exercise. When oral dipyridamole administration was used, a wide range of results for sensitivity, specificity, hemodynamic response and side effect profile has been reported. The authors hypothesized that the formulation used for oral administration of dipyridamole plays a major factor in this variability, and that the pulverized form of dipyridamole will achieve faster and more consistent response than the standard tablet form. The authors studied 13 consecutive patients who underwent thallium scintigraphy. Eight patients received dipyridamole pulverized and dissolved in a glycol/aqueous base diluent (group A), and five patients received the standard form of dipyridamole (group B). In group A, mean peak systolic blood pressure decreased from 142 +/- 31 (mean +/- standard deviation) to 109 +/- 30 (P = .05), and mean diastolic blood pressure decreased from 76 +/- 14 to 51 +/- 5. The mean heart rate changed from 78 +/- 26 to 80 +/- 10. In group B, baseline systolic blood pressure was 165 +/- 12 and decreased to 156 +/- 7 at 45 minutes and to 155 +/- 14 at 90 minutes. Heart rate increased from baseline of 69 +/- 9 to 75 +/- 8 at 45 minutes and to 76 +/- 11 at 90 minutes. At 45 minutes, the systolic blood pressure of the 8 group A patients dropped by 33 +/- 19 mm Hg, whereas group B's changed by 9 +/- 6 mm Hg (P less than .005).(ABSTRACT TRUNCATED AT 250 WORDS)

A rabbit lung model for testing reaction to inhaled dental restorative particles.

A study was designed to test the outcome of the deposition of particles of plastic composite dental restorative material in rabbit lungs. Grinding and polishing these restorations in situ produces some particles in the 0.5- to 10-microns size range that easily enter and remain in human lungs and are associated with industrial lung disease. Dental restorative plastic material was ground in the laboratory, suspended in saline solution, and injected transtracheally into four New Zealand white rabbits. Two control rabbits were similarly injected with saline solution transtracheally. Twenty-four hours later, the rabbits were injected with 1 mCi of 67Ga citrate intravenously and subsequently reanesthetized for scanning. Baseline scans were obtained in the six animals prior to the injection of the test particles. Positive gallium scans were obtained 72 h after the administration of particulate material in the four test rabbits. The gallium scans of the control rabbits remained no different from baseline. The study was repeated one month later. The animals were killed seven days after the last gallium scan. Light microscopy and transmission electron microscopy of the lungs of the test animals showed foci of chronic inflammation around particles of the restorative material. Particles were in vacuoles within alveolar macrophages and also free in interstitium. Control animals had normal histologic conditions. Silver amalgam and gold dental restorations have years of clinical use but the new plastic composite restorative materials are rapidly being introduced into human clinical dental practice. Normal use involves polymerization, grinding, and polishing of the material within the mouth. The chronic inflammation in the lungs of rabbits indicates a need to test dental restorative material for lung biocompatibility before further, extensive clinical use.

Effects of human growth hormone in men over 60 years old.

BACKGROUND: The declining activity of the growth hormone--insulin-like growth factor I (IGF-I) axis with advancing age may contribute to the decrease in lean body mass and the increase in mass of adipose tissue that occur with aging. METHODS: To test this hypothesis, we studied 21 healthy men from 61 to 81 years old who had plasma IGF-I concentrations of less than 350 U per liter during a six-month base-line period and a six-month treatment period that followed. During the treatment period, 12 men (group 1) received approximately 0.03 mg of biosynthetic human growth hormone per kilogram of body weight subcutaneously three times a week, and 9 men (group 2) received no treatment. Plasma IGF-I levels were measured monthly. At the end of each period we measured lean body mass, the mass of adipose tissue, skin thickness (epidermis plus dermis), and bone density at nine skeletal sites. RESULTS: In group 1, the mean plasma IGF-I level rose into the youthful range of 500 to 1500 U per liter during treatment, whereas in group 2 it remained below 350 U per liter. The administration of human growth hormone for six months in group 1 was accompanied by an 8.8 percent increase in lean body mass, a 14.4 percent decrease in adipose-tissue mass, and a 1.6 percent increase in average lumbar vertebral bone density (P less than 0.05 in each instance). Skin thickness increased 7.1 percent (P = 0.07). There was no significant change in the bone density of the radius or proximal femur. In group 2 there was no significant change in lean body mass, the mass of adipose tissue, skin thickness, or bone density during treatment. CONCLUSIONS: Diminished secretion of growth hormone is responsible in part for the decrease of lean body mass, the expansion of adipose-tissue mass, and the thinning of the skin that occur in old age.

Osteopenia in the men of a Veterans Administration nursing home.

We measured by photon absorptiometry the bone density at six sites in 65 nursing home men aged 57-85 y and in 25 independent community men aged 57-80 y. Average bone density in the community men ranged from 97% to 105% of age-matched normal men. In the nursing home men these values ranged from 71% to 92% of age-matched normal men (p less than 0.05 for comparison with the community men). About 50% of the nursing home men but none of the community men had a value less than 70% of age-matched normal men at one or more sites. Among the institutionalized men bone densities at all six sites (in g/cm2) were significantly (p less than 0.05) and directly correlated with body weight but were not significantly correlated with height, age, principal or secondary diagnoses, continuing medications, or functional level.

Absorption of cobalamin (vitamin B12) administered via jejunostomy.

Absorption of cobalamin (Cbl) administered via feeding jejunostomy (J) was compared with that given by mouth (PO) to study the role of transgastric passage in its binding to gastric Intrinsic Factor and subsequent ileal absorption. Modified Schilling tests were performed on 10 patients, each patient serving as his own control. A labeled Cbl capsule was dissolved in 10 cc of water, 7 cc (containing approximately 0.4 microCi 57Co) measured in a syringe and administered PO or via J, followed by 30 cc of water. The remaining solution was used for counting. Starting 1 hour later, following 1 mg of IM cyano-Cbl USP to saturate body storage sites of Cbl, urine was accurately collected for 24 hours and a 4-ml aliquot analyzed for 57Co. Results are expressed as % of tracer excreted in the urine (normal: greater than 7%). The test was repeated in 1 week through the alternate route using the identical protocol. In the eight patients in whom results could be analyzed, absorption was 21.18 +/- 5.83% in J group (range: 5.8-51.9%) and 9.75 +/- 2.62% in PO group (range: 1.9-24.2%). This difference was highly significant p = 0.02) using the paired Student's t-test. Route of the first test (PO or J) made no difference. It is concluded that cobalamin (vitamin B12) administered via jejunostomy is absorbed to a degree significantly greater than that given by mouth.

Nuclear scintigraphy as a diagnostic tool in venous aneurysms.

Aneurysmal dilatation in the low pressure system of internal jugular vein is rare. A case of an aneurysm of the right internal jugular vein, is presented, which was initially diagnosed by nuclear scintigraphy and confirmed by angiography. Clinical presentation, classification, etiology, pathogenesis, and diagnostic modalities of the disease are also reviewed.

Radionuclide detection of blood-retinal barrier disruption in diabetes mellitus.

Diabetic retinopathy is one of the leading causes of blindness in the United States today. Because early treatment of proliferative retinopathy offers the best chance for visual salvation, there is an essential need for methods of identifying eyes at high risk. Recent research has shown that subclinical leakage from retinal blood vessels is one of the earliest signs of retinopathy. The feasibility of using radionuclide techniques to quantitate blood-retinal barrier disruption is demonstrated by a study in which 23 diabetics and 7 nondiabetics were imaged with an Anger camera in the anterior Waters projection at 2 hours after the administration of Tc-99m DTPA. In the digitized images, regions of interest were placed over each orbit and over one of the cerebral hemispheres. Orbital counts were then compared to cerebral counts on a per pixel basis. Eye to brain ratios were found to be lowest for nondiabetics and highest for patients with proliferative retinopathy. Additionally, the dynamic analysis of the same radiopharmaceutical may allow investigators to further study the pathophysiology of the diabetic eye.

Dynamic imaging of the respiratory cycle with 81mKr.

To define the regional ventilation of the human lung, subjects were monitored with a gamma camera, while breathing air labeled with radioactive 81mKr which is being continuously eluted from a generator. The information observed is displayed as a reiterated multiframe moving picture. This is accomplished by storing the information from multiple breaths, selecting acceptable cycles (determined by the duration of inspiration and expiration and the amplitude to extremes of the cycles), and normalizing the usable information and converting the summed data into sequential frames, which are repeatedly shown on a video screen from computer memory.