Mercury exposure of different origins among dentists and dental nurses

Mercury exposure was studied among dental personnel with the use of urinary mercury excretion rates and questionnaires. The study covered 314 dentists and dental nurses employed in public clinics and private practices in Stockholm. The obtained urinary mercury excretion rates were analyzed by stepwise regression for assigning them to different origins, such as environmental factors, number of amalgam surfaces, chewing of gum, kind of employment and profession, age, sex, amalgam handling time, and use of amalgam capsules. On the average the occupational contribution to the total urinary mercury excretion rate was small and of the same order as the contribution from their own amalgam fillings (approximately 2 micrograms of mercury/24 h). There were, however, individuals showing excretion rates close to the levels at which effects on the central nervous system and the kidneys have been reported.     

Influence of the menstrual cycle on skin-prick test reactions to histamine, morphine and allergen

The purpose of this study was to examine the possible influence of the phases of the menstrual cycle on dermal reactivity to skin-prick testing. We studied 15 atopic, menstruating women with seasonal rhinoconjunctivitis and/or asthma, with known sensitivity to olive and parietaria (mean age 25.2 years) and 15 non-atomic, healthy, female controls (mean age 24.7 years). Skin-prick tests with histamine, morphine, and in the atopic group with parietaria/and/or olive, were repeated three times during the same menstrual cycle, corresponding to bleeding (day 1–4), midcycle (day 12–16) and the late progesterone phase (day 24–28). None of the patients had received oral antihistamines or exogenous hormones for at least 1 month prior to testing. Results indicate a significant increase in weal-and-flare size to histamine, morphine, and parietaria on days 12–16 of the cycle, corresponding to ovulation and peak oestrogen levels. This was observed in both atopic and non-atopic women. Differences in skin reactivity to histamine and morphine between the groups were not significant. Therefore, in women, the phase of the menstrual cycle is another factor that may influence skin-test results.     

Craniomandibular disorders with special reference to orthodontic treatment: an evaluation from childhood to adulthood.

The purpose of the present study was to reexamine a group of children and adolescents with respect to signs and symptoms of craniomandibular disorders (CMD) and to evaluate whether any differences could be found between persons who had received orthodontic treatment earlier and those who had not. A total of 402 children in three age groups (7, 11, and 15 years) had participated in a cross-sectional study on the relationship between malocclusion and signs and symptoms of CMD. Ten years later they were asked to answer a questionnaire. In the youngest age groups (now 17 and 21 years old) 190 (76%) subjects answered the questionnaire. In the oldest age group (now 25 years old) completed questionnaires were received from 103 (84%) subjects, and 83 (62%) of those subjects appeared for a clinical examination. Subjects with a history of orthodontic treatment had a lower prevalence of subjective symptoms of CMD (TMJ sounds included) than those without any experience of orthodontics. Although the differences were small, it was more evident for the oldest age group. The clinical examination has shown that persons who had undergone orthodontic treatment had a significantly lower clinical dysfunction index than those who had not.     

Primary phase of hepatocytic autophagocytosis under ischaemic conditions.

Increased autophagocytosis in hepatocytes was found in response to conditions of ischaemia/hypoxia. Initial stages proved to be recordable. These were found to become manifest through the formation of phospholipid membrane structures, approximately 5 nm in width, coalescing in circular formations with vesicular extensions. They may further develop to form multilayer myelin structures. Enveloped cytoplasmic regions and organelles were unchanged, at the beginning, and subsequently coalesced typically into autophagolysosomes and autophagic vacuoles. Verification will be necessary to find out if these initial stages occur only in response to hypoxia or constitute a phenomenon of general validity.     

An in vivo 19F NMR study of isoflurane elimination as a function of age in rat brain.

In vivo 19F NMR at 4.7 T has shown that the biphasic elimination of the vapor anesthetic isoflurane from rat brain is ca 15% slower in old (23-24 months) animals compared with young (5-6 months) animals. The fast kinetic component has a t1/2 of ca 7-9 min and the slow event, 100-115 min. Gas chromatographic measurement of arterial blood elimination displays age attenuation to the same extent, although a monophasic kinetic process (6-7 min). The slow wash-out from brain is thought to involve elimination from intracranial fatty tissue as postulated by others in rabbit brain. Longitudinal relaxation time measurements show monoexponential recovery and essentially identical values for young (1.09 + 0.11 s) and old (1.04 +/- 0.09 s) animals. For dipalmitoylphosphatidylcholine vesicles the monoexponential recovery also suggests rapidly exchanging averaged homogeneous lipid environments for the anesthetic, but the longer T1s (2.75 +/- 0.25 s) imply less restricted mobility compared with brain. Single T2 values were obtained in vivo, indicating either a single compartment or rapid exchange between multiple environments. These measurements were inconsistent, undoubtedly as a result of B1 inhomogeneity. The age-attenuated elimination kinetics for isoflurane are consistent with poorer cardiopulmonary function, whereas the T1 data suggest similar environments for the anesthetic in young and old brain tissue.     

Poliomyelitis outbreak in Natal/KwaZulu, South Africa, 1987-1988. 1. Epidemiology.

An epidemic of type 1 poliomyelitis occurred in Natal/KwaZulu in the eastern part of South Africa between December 1987 and November 1988. 412 poliomyelitis cases were reported, of whom 74% were younger than 5 years. The case-fatality rate was 8%. It is suggested that massive floods, experienced in the area 2 months earlier, triggered the outbreak.     

Effect of diltiazem on silent myocardial ischemia]

Thirty-four patients with coronary heart disease who had silent myocardiac ischemic episodes as evidenced by long-term ECG monitoring were examined. Silent ST-segment elevations and depressions were encountered 2.7- and 4.9-fold as compared to manifest ones. The fact that the CHD patients had silent ST-segment depressions and/or prolonged high-amplitude silent ST-segment elevations suggests a grave severity of abnormal myocardial processes. There was a reduction in the number, duration of silent ST-segment elevations and depression episodes and in the amplitude of silent ST-segment depressions. This may indirectly indicate that the agent affects predominantly coronary blood flow and coronary vascular tone.