Levels of airborne particles resulting from handling alginate impression material

ABSTRACT – The levels of airborne particles emanating from handling alginate impression powders have been surveyed. The concentrations of powders, lead and silicious particles in the aerosol have been measured after thoroughly shaking the containers before opening. The decrease of the powder concentration in the ambient air as a function of time has been estimated. The efficiency of face masks to protect against powder exposure has been investigated.     

The Physical Working Capacity of Healthy Children: Seasonal Variations and Effect of Ultraviolet Irradiation and Vitamin-D Supply

Two groups, each consisting of about 30 children aged 10–11 years, were investigated with regard to physical working capacity, PCW 10–11 and itsannual variations. One of these groups, the test group, received vitamin D on two occasions: on the one hand, a daily dose of 1500 I.U. administered continuously for a period of two months; and on the other, a single massive dose of 400,000 I.U. The effect of vitamin D on PWC which had previously been reported by several authors could not be shown to be of statistical significance. The other group, the control group, like the test group, was subject to seasonal variations in PWC, with a significant minimum in late autumn, November December, and a maximum in April-May. The cause of the observed seasonal variations have been discussed, and it seems that, to a great extent, they were due to variations in physical activity on account of differences in climate and in the length of daylight during the year.
In a smaller group the effect was studied of UV irradiation on PWC, heart volume, blood volume and total hemoglobin, in comparison with those of a control group. No effect of UV irradiation which was of statistical sig nificance was observed in connection with the test group. With regard to PWC and heart volume, both groups showed similar seasonal variations as those found in the larger material. In connection with blood volume and total hemoglobin, a somewhat divergent course was noted, as they increased during the entire period of investigation. The increase was, however, slightly larger during the spring months in comparison with that which was observed during the period October-December and consequently, it appears that also these parameters were subject to some seasonal variations.     

Permanent Pacing in the Elderly

A total of 89 patients, age 80 years or older at the time of initial permanent pacemaker implantation, were followed for 10 to 128 months [mean 32.7]. There were 54 males and 35 females. The mean age was 84.8 years. There were 51 patients age 80-84, 25 age 85-89, and 13 age 90-94. The actuarial 5-year survival was 45%. Complications occurred in 23 patients [40 episodes]. To date, 41 patients have already required at least one pulse generator replacement and 2 patients have already required 5 replacements. All but 3 patients were symptomatic prior to pacing and 56 were asymptomatic at last follow-up. Permanent pacing in the elderly is therapeutically rewarding and not associated with excess morbidity.     

Exposure to mercury and silver during removal of amalgam restorations

The content of particulate matter and mercury vapor in dentist breathing air during removal of amalgam restorations was assessed. Mercury and silver were quantitatively assayed by nuclear chemical analysis, and the mercury vapor concentration was measured with a sniffer. When the water spray was not used, the short time threshold limit values for exposure to mercury and silver were exceeded about 10 times. With water spray the mercury content was reduced to a level considerably lower than the threshold limit value, whereas the silver concentration slightly exceeded the corresponding limit.     

Clinical Experience with a Bradycardia Indicating Pacemaker

The beneficial effect of permanenl pacing is controversial in certain patient groups. Once pacing has been instituted it isseldom terminated and an evaluation of pacemaker depen'dence is therefore not possible. An implantable puise generator, detecting bradycardia beiow 30 bpm has beendeveiopedin order tobroaden ourknowledgeabout the natural history of bradyarrhythmias treated by permanent pacing. This pacemaker has been implanted in 30 patients who did not have clear-cut indications for permanent pacing. They have been followed for a mean of 13 months. Bradycardia was detected in 33 patients 1 to 21 months (4.6 mean) affer implantation. Twenty-one patients did not have a defected bradycardia for Jong periods (months-years). Minor symptoms of lightheadedness a dributable to bradycardia were reported by 15 patients during periods when the pacemaker had been activated. Holter monitoring for at least 24 hours was carried out in all patienls and electronic analysis of explanted generalors was performed in eieven cases. No tecnnical failure relaled to the bradycardia-detecting facility was observed. The combination of diagnostic and therapeutic properties in the bradycardia-indicating pacemaker provides means for safe evaluation of pacemaker dependency over long time periods in patienl groups with controversial indications for permanent pacing.     

Influence of exogenous substrates on adenosinetriphosphate (ATP) concentration in normal and diabetic rat aorta in vitro

In diabetic rat aorta glucose metabolism is impaired and changes in the activities of several enzymes are found. The aim of this study was to investigate whether the metabolic alterations in diabetic vascular tissue influence energy production. Aortas of normal and diabetic male Sprague-Dawley rats were incubated in vitro for up to 120 min with various substrates added to the incubation medium. Diabetes was induced by streptozotocin and the rats were used after a diabetes duration of two weeks. When normal and diabetic aorta were incubated in the presence of 5.6 mmol/1 glucose no significant difference in ATP-concentration was found after 60 min while after 120 min the ATP-concentration was lowered in diabetic aorta. Addition to the incubation medium of a substrate mixture containing amino acids in the same concentrations as in rat plasma, 3 mmol/1 DL-β-hydroxybutyrate and 1.5 mmol/1 palmitate increased the ATP-concentration, measured after 120 min, in diabetic aorta but not in normal aorta. No significant difference in ATP-concentration was found between normal and diabetic aorta incubated in a medium containing all substrates. When diabetic aorta was incubated with each substrate separately β-hydroxybutyrate but not glucose, palmitate or amino acids, increased the ATP-concentration to about the same level as the complete substrate mixture. The results suggest that the ability to utilize glucose for ATP production is impaired in diabetic vascular tissue and that other substrates such as ketone bodies are of importance for energy production in diabetic vessels.     

LOCAL TREATMENT OF TRACHOMA WITH SULFANILAMIDE WITH SPECIAL REFERENCE TO ITS CONCENTRATION IN THE AQUEOUS HUMOR*

Since the publication of the brief report by Heineman (1) on the original use of sulfanilamide in the treatment of trachoma followed shortly by that of more extensive studies of Loe (4a), and Lian (3a), a large number of articles on the same subject have appeared in medical literature. The authors have not been unammous in their opinions in regard to the degree of effectiveness of the drug on trachoma. They may be generally divided into three groups: First, those (2) who con- sider sulfanilamide as of doubtful or of no value at all in the treatment of trachoma; second, those (3) who consider sulfanilamide only as a useful adjunct to the usual local trachoma treatment; (To them. sulfanilamide alone does not cause healing. But it becomes an effec tive agent when used together with other chemical or mechanical measures) snd finally, those (4) who have obtained more or less con- sistently good results with the use of sulfanilamide alone.     

PROGNOSTIC SIGNIFICANCE OF THE 1997 TNM CLASSIFICATION OF RENAL CELL CARCINOMA

PURPOSE: The TNM classification of renal cell carcinoma was recently revised in 1997. The most significant change from the previous edition (1987) is an increase in the size cutoff between T1 and T2 tumors from 2.5 to 7.0 cm. We compared the 1997 and 1987 TNM staging classifications in predicting patient outcome. MATERIALS AND METHODS: A total of 381 patients who underwent nephrectomy for renal cell carcinoma at our hospital between 1968 and 1994 were identified. Mean patient age was 61 years (range 15 to 89) and mean followup was 64.5 months. All pathological slides were re-reviewed in uniform manner and staged using the 1987 and 1997 TNM classifications. The impact of numerous pathological factors and each staging classification on disease specific survival and freedom from progression were statistically analyzed, and Kaplan-Meier survival curves were generated and compared. RESULTS: The 1997 TNM classification resulted in a redistribution of 170 cases previously classified as stage II (T2N0M0) to stage I (T1N0M0) under the new system. Both classifications were strong predictors of survival on univariate and multivariate analyses, and essentially equivalent in the ability to predict patient outcome. However, comparison of survival curves on Kaplan-Meier life tables revealed better separation of survival for stage I (T1N0M0) and stage II (T2N0M0) cases under the 1997 TNM classification, with survival for TNM stage I essentially remaining unchanged. CONCLUSIONS: The 1997 TNM classification of renal cell carcinoma appears to be equivalent to the previous classification in predicting outcome but permits better stratification of cases according to survival and, therefore, may have improved clinical usefulness.