Is There Any Association Between the Presence of Bone Disease and Cumulative Exposure to Lead?

There is evidence from cell culture experiments, animal studies, and from measurements in humans that lead may exert detrimental effects on bone mineral metabolism. In order to explore a possible association between lead and bone disease, both cortical and trabecular bone lead content as well as serum lead concentration was measured in 117 patients who attended a metabolic bone disease clinic (n = 92) or were undergoing dialysis for renal failure (n = 25). Cortical bone lead content was higher in patients suffering from Paget's disease than it was in controls, patients with osteoporosis, and patients on dialysis. Trabecular bone lead content was lowest in patients with Paget's disease or osteitis fibrosa. There was no association between bone lead content and serum alkaline phosphatase concentration in patients suffering from osteoporosis. No statistically significant differences in serum lead concentrations were found between groups. Our results do not distinguish between the two possibilities that increased bone turnover due to Paget's disease releases lead from trabecular bone which is then available for deposition into cortical bone or the alternative possibility that an increased lead content in cortical bone may cause increased turnover with release of lead from trabecular bone. Received: 29 April 1997 / Accepted: 26 January 1998     

Effects of bucolome and related barbiturate derivatives on the displacement of bilirubin from plasma albumin in vivo and in vitro.

Bucolome, one of barbiturate derivatives, lowers plasma bilirubin in Gilbert's syndrome without inductive effect on liver microsomal enzymes. To clarify the mechanism of this action, the study was performed concerning the effects of bucolome and five other closely related barbiturate derivatives including phenobarbital (PB) on plasma bilirubin in homozygous Gunn rats and on albumin-bilirubin binding in vitro. When 15 mg/100 g of bucolome was administered to Gunn rats, remarkable drop in plasma bilirubin continued for more than 48 hrs. This decrease of bilirubin was returned to preinjection level after intravenous injection of albumin. Three Gunn rats died as a result of administration of 30 mg/100 g. This dose caused no pathological change in control rats. In in vitro study, bucolome displaced bilirubin from human albumin strongly. PB had almost no effect on the plasma bilirubin in Gunn rats and the in vitro action was very small. Among the barbiturate derivatives, compounds which have cyclohexyl radicals in N position showed stronger plasma bilirubin decreasing effects in Gunn rats. From these results, a strong action to displace bilirubin from plasma albumin is concluded as the mechanism of bucolome to decrease plasma bilirubin.     

Secretion of an insulinotropic factor from isolated, perfused rat intestine.

To examine gut-islet interrelationships, we entirely separated the gastrointestinal tract from the rat. When we arterially perfused this preparation with an erythrocyte-free solution for 1 h, it remained histologically intact and took up oxygen and glucose. Feedings were given via a duodenal tube. The gut absorbed glucose when glucose in the feeding was high (9.2 g/dl), but not when glucose in the feeding was low (58 mg/dl). With feeding, the portal venous effluent (PVE) from this preparation (stomach to ileum) enhanced late-phase, glucose-induced insulin secretion from pancreas of another rat. This enhancement occurred when the gut was fed either glucose (9.2 g/dl) in electrolyte solution or electrolyte solution alone. PVE from glucose-fed upper gut (stomach, duodenum) was similarly insulinotropic. In contrast, PVE from unfed gut or from glucose-fed gut of old rats was not insulinotropic. PVE from all gut preparations except upper gut produced a glucagon "spike" during basal pancreatic perfusion. Effects of gastrointestinal peptides (gastric inhibitory polypeptide, cholecystokinin octapeptide, secretin, gastrin) and immunoassays of PVE suggested that the insulinotropic substance is not one of these peptides. Thus, an insulinotropic substance that is not dependent on feeding nutrient material is secreted from the intestine.     

Detection of T-factor in lung cancer using magnetic resonance imaging and computed tomography

The ability of magnetic resonance imaging (MRI) to detect T-factor was compared with that of computed tomography (CT) in 52 patients with primary lung cancer proven by surgery or autopsy, and the results were analyzed in relation to the operative and pathologic findings. In the diagnosis of tumor invasion of the heart and great vessels, MRI provided information as accurate as CT. The T1-weighted images in particular were of considerable value in separating the tumor from the mediastinal and hilar fat. Tumor extent in accompanying peripheral obstructive pneumonia or collapse was demarcated in 21% of the cases studied by CT and in 33% to 53% by MRI. On the other hand, the T2-weighted images obtained with longer echo time (TE) were useful in distinguishing the tumor from secondary changes.     

OSTEOSARCOMA Ultrastructural and Immunohistochemical Studies on Alkaline Phosphatase-positive Tumor Cells Constituting a Variety of Histologic Types

The osteosarcomas were subclassified into osteoblastic, fibroblastic, chondroblastic and telangiectatic types and examined by electron microscopy. Their immunohistochemical reactions were also studied. In an overall survey of the above types, fibroblast-like cells revealed poorly developed cytoplasmic organelles with rather short, branching rough endoplasmic reticulum, mixed with osteoblast-like cells that were hardly distinguishable from the former. They appeared to be an early stage of an osteoblastic cell lineage from the distribution and development of their cell organelles and highly positive vimentin activity. The tumor cells in malignant cartilage varied in appearance from chondroblast-like to osteoblast-like cells. All types of tumor cells expressed alkaline phosphatase activity to a significant degree. Immunohistochemical staining showed a mixture of procollagen type I-positive cells among the cells positive for both procollagen type II and S-100 protein in the malignant cartilage. Irrespective of any ultrastructural differences between these various tumor cell types, they all revealed a significant degree of ALPase activity unlike other types of bone tumors, suggesting that the tumor cells which constitute the various types of osteosarcoma are derived from a common precursor cell.