Internal irradiation from nuclear medicine investigations: a comparison between effective dose equivalent and effective dose

ICRP Publication 60 (1990) proposes a partially revised method to calculate effective dose, a quantity previously defined in ICRP Publication 26 (1977) as effective dose equivalent. The authors applied these two different approaches to calculate the effective dose equivalent and the effective dose, in the case of internal irradiations from the most common nuclear medicine investigations. The results show clear differences between the two examined quantities, even if the differences are not statistically significant.

Evaluation of most frequent errors in daily compilation and use of a radiation treatment chart

Between 1 March and 30 April (1994) we recorded the errors detected by the physician, the radiographer or the physicist during prescription, preparation and execution phases of 227 treatment plans. The radiation treatment modalities used were the following: (i) single or opposed fields, moulded or not; and (ii) multiple fields or kinetic techniques. The total number of sessions performed is 1613 with the cobalt unit and 2131 with the linear accelerator (total, 3744). The total number of wrong data is 155, consisting of 24/227 (10.5%) in compilation, 22/3744 (0.58%) in execution and 109/3744 (2.9%) in registration phases. The number of missing data is 140, consisting of 10/227 (4.4%) in compilation, 9/3744 (0.2%) in execution and 121/3744 (3.2%) in registration phases. Wrong data of compilation, even if in high rate (10.5%), were all found during the same compilation phase or at the first treatment, so that they did not alter the exactness of the treatment plan. Wrong and missing data, found in the registration phase (2.9% and 3.2%, respectively), depend on the repetition of daily treatment and on the registration of data on the chart after having digitized them on the display.

An epidemic of infantile papular acrodermatitis (Gianotti-Crosti syndrome) due to Epstein-Barr virus

Five out of twelve 13- to 15-month-old children, attending the same class of a crèche in Forlì (Italy), presented infantile papular acrodermatitis (Gianotti-Crosti syndrome), associated with lymphocytosis and evidence for a recent Epstein-Barr virus infection. This cluster may be due to two facts: (1) the long and close contacts among the patients and (2) the concurrent immunization with a combined diphtheria-tetanus-pertussis-poliomyelitis vaccine from 2 to 6 weeks previously.

[Diabetes and atherosclerosis: a follow-up echographic study of atherosclerotic carotid lesions]

A two years follow up on 105 diabetic patients and 50 normal subjects was carried out by high resolution real time echotomography, aiming to evaluate the prevalence and the evolutionary trends of carotid atherosclerotic plaques. The prevalence of atherosclerotic lesions was higher in diabetic patients than in normal subjects, and the most part of them showed an "intermediate" echographic pattern, minimal stenosis and regular surface. The results of the two years follow up indicate that the "soft" and the "hard" plaque types were those showing a more significant progression toward to the "mixed" type. "Hard" and "mixed" plaques, particularly those showing irregular surface, resulted most associated with higher degree of vessel stenosis. Four diabetic patients experienced three minor and one major ischemic events during the follow up; however all the patients had shown plaques with "intermediate" pattern, regular surface, and no signs of vessel stenosis progression. Further studies, performed for longer period of time with a higher number of patients are needed to evaluate the evolutionary trends of carotid plaques in diabetic patients and their relationship with clinical ischemic events.

Does anxiety underly imidazole-induced behavioural effects in the rat?

Since behavioural symptoms (tremor, irritability, pilo-erection and shaking) induced by imidazole (IMID) in rats suggested an underlying modification of arousal and/or emotionality, further studies were performed in order to extend the range of behavioural influences of IMID. In the open-field test, IMID (37.5-300 mg/kg IP) inhibited crossing and rearing in a dose-dependent fashion, this effect being long lasting (about 3 h at 75 mg/kg). Yohimbine (YOH) (1, 5 and 10 mg/kg IP), described as anxiogenic and fear-inducing in animals and in man, when investigated in this same test, inhibited the activity of rats similarly to IMID. Since diazepam (0.5 and 1 mg/kg) but not clonidine (0.075 and 0.150 mg/kg IP) pretreatment reversed IMID- and YOH-induced hypomotility, the hypothesis that IMID effects in the open field might reflect an anxiety-like state was investigated by means of social interaction and x-maze, two tests considered highly specific for anxiety studies. The data obtained show that IMID depresses social interactions only at doses inhibiting motor activity; YOH, in our experimental conditions, produced a similar effect. In an elevated x-maze, with alternate open and closed arms, IMID (37.5 and 75 mg/kg) decreased the proportion of open-arm entries and the time spent in them, an effect prevented by diazepam pretreatment (1 mg/kg IP). Finally, mean arterial pressure (MAP) was assessed in anesthetized rats treated with IMID and YOH at doses equivalent as regards behavioural effects. MAP was increased by IMID whether IP or IV and decreased by YOH; moreover, YOH, as expected, antagonized clonidine-induced hypotension, while IMID was ineffective.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro effects of polyhalogenated hydrocarbons on liver mitochondria respiration and microsomal cytochrome P-450

The present study evidenced the critical levels of six major polyhalogenated hydrocarbons (PHH's), namely chloroform, carbon tetrachloride, 1,1,1-trichloroethane, 1,2-dibromoethane,perchloroethylene, hexachlorobutadiene, over which significant inhibitory effects of the mitochondrial respiratory chain take place in vitro. At these critical levels, even in PB-induced animals only a very little fraction of cytochrome P-450 is saturated by the compounds and therefore the microsomal metabolism plays no effective role either in decreasing the levels of the test chemicals under the threshold of clear direct adverse effects in mitochondria, nor to the formation of toxic metabolites. Our data show also that phenobarbital not only enhances both the direct and metabolism-mediated interaction of most tested PHH with microsomal cytochrome P-450, but also increases the affinity of hexachlorobutadiene, chloroform and carbon tetrachloride for the mitochondrial sites resulting in respiration inhibition.

Blood pressure levels in urban school-age population in Chile

Two blood pressure (BP) measurements separated by 3 months were performed according to international guidelines on 2976 students (11 to 19 years) of different economic levels. Obesity was defined based upon height and weight. With the first measurements, 59th and 95th percentile value distribution curves were defined. Systolic hypertension (SH) was found in 9.5%; 10.2% were males and 8.9% females. The sample showed that 8.1% were obese (240 cases); among them the incidence of SH increased to 28.8% (69 cases) (p less than 0.01). In the entire sample, diastolic hypertension (DH) was 4.3%; males, 2.7%, and females, 5.5% (p less than 0.01). Among obese students, DH increased to 8.3% (20 cases) (p less than 0.01), and showed prevalence figures of 5.8% for obese males and 10.3% (14 cases) for obese females. After a second measurement, DH for the sample decreased to 1.8%. Salt intake and familial antecedents of high BP showed differences between hypertensive and normal populations.