Wahner, Heinz W.

In right-sided extracardiac conduits inserted for surgical correction of certain congenital heart defects, obstruction is a significant late complication requiring conduit replacement in about 5% of the patients. Our histopathologic study indicates a significant role of platelets in the pathogenesis. This study was designed to evaluate the feasibility of imaging procedure with 111-Indium-labeled platelets to localize and later quantify platelet accumulation in the conduits. Four patients with pulmonary atresia and 1 with truncus arteriosus underwent conduit placement, 2 with and 3 without porcine valve. Autologous platelets collected.from 43 ml of blood drawn prior to surgery were labeled with 111-Indium-oxine in ACD-saline medium (labeling efficiency 50-60%). 400-500 μCi of autologous 111-Indium-labeled platelets were administered intravenously immediately after surgery in 4, and five days after surgery in 1 patient. Imaging was performed at 6 hours and daily for 1-4 days using a portable gamma camera interfaced with a computer and fitted with medium-energy parallel hole collimator. Platelet deposition was noted at the site of the conduit in all 5 patients. Maximum accumulation (0.1-0.3% of dose) of platelets was seen within the first 24 hours. Activity over blood pool and lungs declined and over liver and spleen increased in a predictable manner over the imaging period. This technique has potential use as a noninvasive quantitative tool to study the effect of platelet inhibitor drugs in preventing conduit obstruction.

1. If gastric acid is necessary for the absorption of dietary calcium, the total absence of gastric acid secretion that occurs in pernicious anaemia could result in bone loss. To investigate this, we measured calcium absorption and bone density in 21 postmenopausal women (ages 51–76 years) with pernicious anaemia and in 24 normal postmenopausal women (ages 51–79 years). 2. Relative to the normal women, in the women with pernicious anaemia the bone mineral density of the lumbar spine was decreased by 16% (P < 0.001). 3. After adjustment for age and body weight, lumbar spine bone mineral density correlated with the serum concentration of group 1 pepsinogens (a group of proteins produced by the gastric fundus) (r= 0.61, P < 0.01). 4. Despite achlorhydria, the women with pernicious anaemia had normal true fractional calcium absorption and normal serum levels of parathyroid hormone and 1,25-dihydroxyvitamin D. 5. We conclude that gastric acid is not required for the absorption of dietary calcium. Thus, the loss of cancellous bone must be caused by some mechanism yet to be identified.

ABSTRACT In four groups of subjects free of thyroid disease, the following determinations were made: serum concentrations of thyroxine (T 4 ), triiodothyronine (T 3 ), reverse T 3 (rT 3 ) and diiodothyronine (T 2 ), and calculated indices of free thyroxine (FT 4 ) and free triiodothyronine (FT 3 ). Group A comprised healthy subjects aged 16–64; Group B, 24 healthy elderly subjects aged 68–95; Group C, 23 elderly patients with mild well‐controlled chronic illnesses, aged 70–85; Group D, 40 nursing home residents aged 66–100. Serum T 4 and T 2 concentrations and the FT 4 index were not affected by age; the rT 3 concentration was slightly but significantly elevated only in Group D patients. Serum T 3 concentration was significantly lower in all groups of elderly subjects and decreased FT 3 index measurements were detected after age 75. It was concluded that old age, without complicating illness, is accompanied only by a decrease in the serum level of T 3 and the FT 3 index; values for other iodothyronines are unchanged. Clinicians should consider the age‐related changes in T 3 and FT 3 values when interpreting thyroid function tests.

Abstract Seasonal variation in physical activity, back extensor muscle strength (BES), and bone mineral density (BMD) of the lumbar spine was studied in 65 healthy postmenopausal women. Physical activity score (PAS) was assessed with an ordinal scale (0-18); this score and the BES were obtained monthly for 2 years (25 readings). BMD values were obtained semiannually (5 readings). A periodic (cosine) regression model was fit to each subject's PAS and BES data to obtain individual estimates of the annual peak day d and the average annual range due to seasonality. There was a strong (P < 0.001) seasonal pattern in physical activity; August 3 was the average peak day, and the seasonal range was 2.0 PAS units. There was modest (P = 0.047) seasonality in BES; June 6 was the estimated peak day, and the seasonal range was 8.22 pounds (about 7% of the mean). BMD averaged 0.015 g/cm2 higher in August through November than February through May (P = 0.002), and the highest monthly average BMD was in August. This seasonal range of 1.4% is larger than the average annual decline with age in BMD observed in longitudinal studies of postmenopausal women. The results of this study have important implications for the planning of longitudinal studies involving changes in physical activity or bone mass in geographic areas with diverse seasons.

Abstract To determine whether Colles' fracture, generally considered a manifestation of postmenopausal osteoporosis, is associated with a decrease in bone density at the site of fracture, we measured bone mineral density of the ultradistal radius (UDR-BMD) by single-photon absorptiometry with computer-assisted image processing. In 119 normal women (ages 22–92 years), UDR-BMD decreased by 17% between ages 30 and 75 years. From UDR-BMD measurements in these normal women and in 40 women (ages 53–80 years) with Colles' fracture alone, a population-based analysis was made to estimate fracture risk at different values of UDR-BMD. Colles' fracture was uncommon at UDR-BMD > 0.40 g/cm2 (the “fracture threshold”). As bone density decreased below this level, fractures became more frequent (a “gradient of risk”).

Abstract Although it is a cardinal feature of involutional osteoporosis, there is often disagreement on what constitutes a vertebral fracture. We measured vertebrae T4-L5 in 52 healthy women to develop a normal range (mean ± 3 SD) for vertebral shape and used these data to assess the prevalence of vertebral fractures. We classified vertebral fractures by type of deformity (wedge, biconcavity, or compression) and further by the degree of deformity (grades 1 and 2). In 195 postmenopausal women who were an age-stratified random sample of the Rochester population (ages 47–94), 40 (21%) had vertebral fractures (mean, 2 per person). There was a similar number of compression and wedge fractures, and grade 2 fractures were as common as grade 1. In a referral sample of 74 women with suspected osteoporosis, 62 (84%) had vertebral fractures (mean, 3.3 per person). Wedge fractures were most common, and grade 2 fractures were more common than grade 1. The distribution of type and grade of fractures differed between the two patient groups (P < 0.01). Bone mineral density of the lumbar spine was related to mean fracture grade (r = −0.33, P < 0.05) and to fracture number (r = −0.57, P < 0.001) but not to fracture type. We conclude that a comprehensive approach is required in describing vertebral fractures. Using this approach we found distortion in the fracture characteristics of women referred to an osteoporosis clinic compared to women in the community.

Abstract High caffeine consumption has been proposed as a risk factor for osteoporotic fracture, but the evidence associating high caffeine intake with low bone density is inconsistent. We therefore examined the influence of caffeine consumption on bone mineral at six skeletal sites in an age-stratified random sample of white women residing in Rochester, Minnesota. After age adjustment, there was no association between overall caffeine consumption and bone mineral at five of the six sites. In the femoral shaft, however, there was a statistically significant interaction between age and caffeine consumption so that high caffeine intake was associated with slight reductions in bone mineral among elderly subjects but with modestly increased bone mineral at younger ages. When caffeine intake was categorized by source, no consistent influence of coffee, tea, or other caffeinated beverage consumption could be detected on bone mineral. Caffeine intake was, however, positively associated with cigarette smoking and alcohol consumption. After adjusting for age, caffeine consumption was not correlated with biochemical indices of bone turnover, circulating concentrations of estradiol and estrone, or other dietary and musculoskeletal variables. These data suggest that caffeine intake in the range consumed by a representative sample of white women is not an important risk factor for osteoporosis. Among elderly women, however, in whom calcium balance performance is impaired, high caffeine intake may predispose to cortical bone loss from the proximal femur.