Fluoride therapy in osteoporosis: acute effects on parathyroid and mineral homoeostasis

1. Acute metabolic effects of sodium fluoride therapy were analysed among 41 osteoporotic patients already receiving large calcium supplements, 33 of whom underwent simultaneous metabolic balance studies. 2. Mean serum calcium fell transiently within 24-48 h by 0.03 +/- 0.07 (SD) mmol/l (P less than 0.01) and phosphorus by 0.06 +/- 0.08 (SD) mmol/l (P less than 0.001). In a subgroup, ionized calcium fell and biologically active parathyroid hormone (bio-PTH) rose more than fivefold (P less than 0.01). Urine calcium rose after an insignificant fall. 3. Pretreatment calcium and phosphorus balances were significantly positive and did not change overall during the first 8 days of treatment. However, on analysing balances in two groups relative to serum changes, in patients whose serum levels changed least sodium fluoride increased faecal calcium (P less than 0.025) and phosphorus (P less than 0.01) and reduced calcium balance (P less than 0.01), giving a mean balance difference between the two groups of 2.1 mmol daily (P less than 0.001). 4. Very small changes in serum levels therefore indicate well-marked metabolic responses: sodium fluoride acutely stimulates bio-PTH activity and must also enhance mineral uptake from circulation into tissue(s). By separate and opposing action(s) it inhibits intestinal calcium and phosphorus absorption, predominantly in those whose serum levels remain stable. All these effects may be relevant to long-term therapeutic results.     

Pseudoprominent aorta: radiographic findings and CT correlation

The presence of a persistent left-sided superior vena cava (LSVC) in the absence of a right-sided superior vena cava (RSVC) may be suspected on a posteroanterior (PA) chest radiograph because of a prominent-appearing ascending aorta, which results from the absence of the RSVC. In the absence of an RSVC, the right upper lobe abuts and outlines the course of the ascending aorta, allowing better demonstration of its profile. This report describes a patient with this finding on a PA chest radiograph. Computed tomographic correlation is presented.     

Neutrophil labeling with indium-111: tropolone vs. oxine

This study was undertaken to compare tropolone with oxine (8-hydroxy-quinoline) for labeling human neutrophils with In-111. Exposure of neutrophils to tropolone at concentrations required for efficient labeling resulted in a marked impairment of chemotaxis. In contrast, no impairment of neutrophil chemotaxis was observed using In-111 oxine. Labeling efficiencies obtained with In-111 tropolone under optimal conditions were consistently less than those obtained with In-111 oxine. We evaluated cells labeled by the two methods using chemotaxis radioassay to assess the chemotatic potential of labeled cells. The results led to the conclusion that the oxine technique is preferable to tropolone for labeling human neutrophils with In-111.     

Current developments in oxygen concentrator technology

Oxygen concentrators are electrically powered devices which are designed to provide oxygen for patients who require long-term domiciliary oxygen. The machines have been available for the last 10 to 15 years, but it is only recently that improvements in design have led to them being generally accepted as a reliable and economical means of supplying long-term oxygen therapy. There are two basic types of concentrator currently available: the molecular sieve (MS) concentrator, and the membrane oxygen enricher. In this article the characteristics and principles of operation of these machines are reviewed, together with the development and present state of MS concentrator technology. A summary of a comparative evaluation of seven MS concentrators is presented and the results discussed. Relevant safety standards and current trends in concentrator design are then reviewed.     

Peripheral blood stem cell collection and use in Hodgkin''s disease. Comparison with marrow in autologous transplantation

Hematopoietic progenitor cells can be collected from blood by cytapheresis; the clinical use of these cells may offer such advantages over marrow as the avoidance of general anesthesia, collection on an outpatient basis, and use when marrow is involved with malignancy. Since Hodgkin's disease rarely spreads hematogenously, postchemotherapy marrow transplantation with autologous peripheral blood stem cells (PBSCs) was compared to that with marrow transplantation in patients with this disorder. Seven patients were treated with PBSCs and 19 with marrow. Five to nine collections of PBSC were performed per patient. There was a rebound increase in circulating committed progenitors when PBSC were collected during the marrow rebound after cyclic chemotherapy. After intensification and cellular rescue, quicker recovery of circulating white cells (p less than 0.05) and a shorter hospital stay (not significant) were seen in the PBSC patients than in those treated with autologous marrow. There was no difference in the duration of red cell or platelet transfusion required after transplant. Of six patients whose marrows were previously involved by Hodgkin's, recurrent or progressive disease has occurred in five. PBSC may be a viable alternative to marrow in selected patients.     

Predictive value of signs and symptoms for colorectal cancer in patients with rectal bleeding in general practice

The aim of the study is to determine the diagnostic value of(combinations of) signs, symptoms and simple laboratory testresults for colorectal cancer in patients with rectal bleedingpresenting in general practice. Initial complaints and findingswere compared with the final diagnoses based on clinical follow-upafter at least 1 year. Patients studied were those presentingovert rectal bleeding to the general practitioner (83 GPs inthe South of the Netherlands). Outcome measures are sensitivity,specificity, predictive values, odds ratios and a predicitionmodel derived from multiple logistic regression analysis. Age,change in bowel habit and blood mixed with or on stool showa statistically significant independent value in the discriminationbetween patients with a low and those with a high probabilityof colorectal cancer. Many other variables did not show predictivevalue. The prediction model has a sensitivity of 100% and aspecificity of 90%. Although the number of patients with colorectalcancer is small (n=9) it was possible to identify three characteristicswhich can be helpful in the prediction of presence or absenceof colorectal cancer in general practice. Application of themodel presented might prevent 90% of ‘unnecessary’invasive diagnostic procedures for patients with rectal bleedingwho do not have colorectal cancer (true negative). Testing theperformance of the model in other general practice populationsis recommended.