A case-control study was conducted among the multiethnic population of Singapore to test the hypothesis that a high level of body burden mercury is associated with an increased risk of Parkinson''s disease (PD). Selected factors investigated that could contribute to the body burden of mercury included dietary fish intake, ethnic over-the-counter medications, occupational exposures and possession of dental amalgam fillings. Detailed interviews were completed in 54 cases of idiopathic PD and 95 hospital-based controls, matched for age, sex and ethnicity, between July 1985 and July 1987. After adjusting for potential confounding factors, including dietary fish intake, medications, smoking and alcohol consumption, there was clear monotonic dose-response association between PD and blood mercury levels. The odds ratios (OR) and 95% confidence intervals (CI) for the approximate subject tertiles based upon blood mercury levels were 8.5 (CI = 2.2–33.2) and 9.4 (CI = 2.5–35.9), relative to the tertile with lowest blood mercury levels (< 5.8 ng Hg/ml). Similar associations were revealed using scalp hair and urinary mercury levels. However, only the comparisons between the highest and lowest tertiles were statistically different from unity (p < 0.05). When the body burden mercury indicators were mutually adjusted in addition to the four confounding factors, blood and urinary mercury levels showed ORs of 21.00 and 18.65, respectively. These ORs were statistically different from unity (p < 0.05, 2-sided test). After adjustment, scalp hair mercury was shown to be a poor predictor of PD risk.

The craniofacial complex of two neonatal, human, cyclopic specimens was studied in detail. Both specimens exhibited a single ocular opening and one had a prominent probosics positioned in the midline directly superior to the ocular aperture. No external nasal development was noted in the other specimen. The most remarkable finding was the lack of development of all skeletal derivatives of the ethmoidal cartilage(cribriform plate, perpendicular plate, superior and middle nasal conchae, medial orbital walls, and nasal septal cartilage) in both specimens. Since these bones normally form the medial, lateral, and superior walls of the nasal passage, this cavity was also absent. The two posterior halves of the maxillae were directed superiorly, medially, and with the vomer merged in the midline as a thick mass of bone. As a result the right and left alveolar portions of the maxillae were joined superiorly in the midline. With the absence of the nasal cavity, the right and left medial pterygoid plates merged medially with the palatal and pyramidal processes of the palatine bone to obstruct the junction between the oropharynx and nasopharynx(choanal atresia). The role of the skeletal parts of the ethmoid during maxillofacial growth and development is discussed.

The rules governing the use of metallic mercury, a toxic and hazardous chemical, is in most jurisdictions identical to widely accepted standards and practices for handling the same chemical in industry for the protection of humans and their work environment. There cannot be exceptions solely for the practitioner dentists and their patients. Any workplace must be safe for both workers and visitors. The latter being dental patients waiting in the dentist's work environment. We reviewed the literature for toxic health effects of elemental mercury upon humans and present information about the Minimata Convention convened by the United Nations Environment Programme. A study conducted among dentists in Singapore and their personal work environment almost 30 years ago contributed to the workplace standard for elemental mercury, which was reduced, and is still currently enforced as a global standard. We recommend that dentists, with a large alternative battery of restorative materials today, make selection of a restorative material a more seriously considered choice, and not to make use of amalgam without the proper use of personal protective equipment for themselves (members of the dental operating team) and their patients, (amalgam traps and judicious monitoring of their workplace air quality). Mercury is ubiquitous in our presence due to human activities; any reduction in the dentists' workplace contributes to a global reduction.

The influence of reaction time upon stannous (II) chloride as a reductant in the cold-vapor atomic absorption spectrophotometric method was investigated. In this comparative study, virtually all operating conditions, including volumes and chemicals used, were made identical except for the redesigning of the reaction vessels. The use of a reaction mixing time of 2 minutes (TR method), rather than immediate bubbling with aspiration (IL method) of total mercury from undigested biological samples, has several advantages. There is an average 4.5-fold increase in sensitivity of peak height readings with virtually no loss of mercury vapor from the reaction vessel by diffusion. Using the TR method also eliminated interaction of mercury with the matrices investigated, viz., undigested blood, undigested saliva, undigested urine, and digested hair samples. The average recovery for the TR method was superior to the IL method, 99.3 +/- 3.2% vs. 84.7 +/- 3.3%, p less than 0.05. In addition, mercury concentrations determined with the TR method were identical using either peak area or peak height readings. It was also found that concentrations determined using either the formulae given by Magos and Clarkson (4) and Farant et al. (5) or an aqueous calibration curve were equivalent. Only 0.2-1.0 mL of biological samples was needed for each analysis in the study.

Introduction: Evidence has shown an increase in paediatric hypertension globally and this could give rise to increase prevalence of adult hypertension. The purpose of this paper was to determine the prevalence of hypertension among adolescents in Malaysia as well as the association between hypertension and lifestyle factors selected based on published literature. Methods: Adolescents aged 13-17 years old were selected randomly from two secondary schools to have their blood pressure measured. Their lifestyle information was obtained through completed bilingual questionnaires based on validated instruments, as well as anthropometry measurements. The relationship between hypertension and lifestyle factors was determined through statistical analysis. Results: A total of 273 students were included in the study with 120 (44%) males and 153 (56%) females. The prevalence of hypertension was 24.5% among the respondents with the highest being recorded among Malays (28.7%). Generally, hypertension was associated with an increased Body Mass Index (BMI) (AOR=4.053, 95%CI=1.677-9.795, p=0.002) and waist circumference (WC) (AOR=2.918, 95%CI=1.171-7.269, p=0.021) in all respondents. Similar associations were noted in females (BMI: AOR=7.707, 95%CI=2.043-29.072, p=0.003; WC: AOR=3.690, 95%CI=1.011-13.464, p=0.048) but not in males. Conclusion: Hypertension recorded high prevalence among Malaysian adolescents in our study. The strong association between elevated body weight, BMI and WC with hypertension may require further study to evaluate the need for screening