PubMed Health⌕ Search

Biomedical subjects

G Vimpani

Publications and source records attributed to G Vimpani.

At least 19 recordsLinked to original sources
PubMed1998

Blood lead-urine lead relationships in adults and children.

To determine the potential for using instead of blood as an indicator of lead exposure, especially in infants, lead concentrations and high-precision lead isotopic measurements have been compared in venous blood and "spot" urine (n > 260 from 182 different subjects) collected within the same 24-h period. Physiological conditions for the children and most of the adults were considered to be in a steady-state between body stores and lead in the environment. In the case of some adults, conditions were initially not steady-state because exposure conditions changed (for example, subjects moved to a country with lead of different isotopic composition.) There was a high correlation (r2 = ) between the blood and urine measurements of the isotope ratios but about 10% of measurements were outliers--the blood and urine measurements were further apart than was consistent with the measurement error that was generally obtained. The discrepancy was usually found to be associated with the urine measurement and was attributed to contamination during sampling. Weekly urine and monthly blood monitoring of an adult male over a 24-month period showed and excellent correlations, although the standard deviations were about an order of magnitude higher than the precision measured for replicate analyses of a single blood or urine sample. "Spot" urine analyses for two male subjects gave excellent agreement with 24-h urine samples. Standard deviations of the spot analyses were of similar order to those in the 24-month monitored subject. In cases where female adults from Eastern Europe migrated to Australia, there was generally a more rapid exchange of skeletal lead with Australian environmental lead in urine compared with blood. These data do not support a differential partitioning of endogenous lead into the plasma. At this stage, isotopic measurements of urine can be used as a proxy for isotopic measurements in blood. However, lead concentrations in blood and in urine are only weakly related. Concentrations of lead in urine cannot serve to predict concentrations of lead in blood, particularly at the lower range of exposures, for example, at blood concentrations less than 10 microgram/d1.

Adult↗
PubMed1998

Does breastfeeding at six months predict cognitive development?

There is controversy over whether the method of feeding in infancy affects intellectual development. We investigated the relationship between breastfeeding status at 6 months of age and long-term cognitive development in a cohort of 375 children born in Port Pirie, South Australia, between 1979 and 1982. Cognitive assessments were conducted at ages 2, 4, 7 and 11 to 13 years. After adjustment for sociodemographic, environmental and biomedical factors, a small, statistically non-significant, beneficial effect of breastfeeding on cognitive functioning was observed. Compared with the bottle-fed children, the breast-fed children had a 3.4 (95% CI -0.1 to 6.9), 1.3 (-2.3 to 4.9), 1.2 (-2.0 to 4.4) and 0.8 (-1.9 to 3.5) point advantage on the Bayley Mental Developmental Index at age 2 years, the McCarthy General Cognitive Index at age 4 years and the Wechsler Full-Scale IQ at ages 7 and 11 to 13 years, respectively. Our data suggest that any beneficial effect of breastfeeding on cognitive development is quite small in magnitude.

Analysis of Variance↗
PubMed1997

Pregnancy increases mobilization of lead from maternal skeleton.

The question of the extent of lead mobilization from the maternal skeleton during pregnancy and lactation is one of the most outstanding problems of lead toxicity. We have undertaken a longitudinal cohort study in an urban environment of European female immigrants of child-bearing age (18 to 35 years) to Australia whose skeletal lead isotopic composition has been determined to be different from that in their current environment. The cohort was to consist of 100 immigrants anticipated to provide 20 pregnant subjects who would be compared with two groups of control subjects: a matched immigrant nonpregnant control group and second-generation Australian pregnant control subjects. Pregnant subjects also serve as their own controls for a comparison of changes during gestation with those before conception. High-precision lead isotopic compositions and lead concentrations are measured in maternal blood and urine prenatally, monthly during gestation, and postnatally for 6 months; they are also measured in infant blood and urine for 6 months; environmental measures are sampled quarterly for 6-day duplicate diet, house dust and water, and urban air and gasoline. Because of continuing public health concerns about lead exposure, interim findings from this cohort are being reported. To date there have been 13 conceptions in immigrant subjects, with 7 births, in addition to 3 conceptions in the Australian control group, with 2 births. PbBs have been generally low, with a geometric mean of 3.0 microg/dl, and have ranged from 1.9 to 20 microg/dl. Increases in PbB of approximately 20% during pregnancy have been detectable even in subjects with low blood lead levels. The skeletal contribution to blood lead level, based on isotopic measurements, has exhibited a mean increase (and standard deviation) of 31% +/- 19% with a range from 9% to 65%. Earlier studies that used lead concentrations only have suggested that blood lead levels increased only during the second half of pregnancy. This increase in blood lead levels has also been observed in the present study. However, in two subjects the increases in total blood lead were also detected in the first 2 months of pregnancy. Changes in isotopic composition and blood lead during gestation for Australian pregnant controls were negligible. The ratio of cord/maternal blood lead levels varied from 0.54 to 1.05, and the ratio for the isotopic composition was 0.993 to 1.002. Results of this study confirm that lead is mobilized from skeletal stores at an accelerated rate during pregnancy and is transferred to the fetus. These results also show that mobilization from long-term stores (i.e., bone) contributes significantly to blood lead levels during pregnancy. Furthermore, exposure of the fetus to lead during pregnancy has implications for interpretations of neurobehavioral disorders attributed to only postnatal exposure. Even after 800 days of residence in Australia, the contribution of European skeletal lead to blood lead in nonpregnant subjects can be on the order of 50%, but the current PbB may give no indication of the former high skeletal lead burden.

Adolescent↗
PubMed1997

Opportunistic blood lead testing in a paediatric inpatient population.

We report a simple protocol which has potential to estimate community paediatric blood lead levels using opportunistic testing. Permission to use leftover blood for a lead assay was sought from parents or guardians of 397 children one month to 13 years of age who were admitted to general paediatric wards of John Hunter Hospital, Newcastle, between May and August 1993 and who had blood for a full blood count taken for any reason. Results were reviewed by a medical officer and returned to parents. Where a child's blood lead level was of concern according to National Health and Medical Research Council guidelines, the child was referred to a specialist paediatrician for clinical assessment. Written consent was received from the parents or guardians of 95.5 per cent of eligible children (n = 379); 93.4 per cent of responders (354 of 379) had blood suitable for testing, giving an overall result rate of 89.2 per cent (354 of 397). The mean blood lead level for the whole group was 5.3 micrograms/dL. The highest blood lead level for any age group was 6.4 micrograms/dL in the 36 to < 60 month age group. Stratification by geographical area showed a trend in increasing blood lead with increasing population density and areas where lead polluting industries exist. The approximate cost per result achieved was $40. This opportunistic survey method provides a promising technique for obtaining data on community blood lead levels. It may be a practical and resource-efficient alternative to large-scale community surveys. Further studies are under way to validate the method as a community surveillance tool.

Adolescent↗
PubMed1995

Could your young patient have lead poisoning?

While clinical symptoms of classic lead poisoning are rare in Australian children, elevated body lead burden may have a small but treatable contribution to developmental and behavioural problems in individual children; its cumulative neurodevelopmental impact on populations of children is a greater public health concern. Children with blood leads over 15 micrograms/dL require blood lead monitoring and if persistently elevated assessment of potential environmental sources is indicated; children with lead levels over 25 micrograms/dL should be seen by a paediatrician. Chelation is not indicated in children with blood leads less than 55 micrograms/dL.

Child Behavior↗
PubMed1995

Contribution of tissue lead to blood lead in adult female subjects based on stable lead isotope methods.

Public health and medical recommendations on prevention of lead toxicity rely on use of blood lead concentrations to assess lead exposure and predict onset of adverse health effects. Blood lead levels have generally been thought to reflect recent environmental lead exposures. However, tissue lead stores are accumulated over a long time period (i.e., years). These tissue stores, primarily from bone, can be remobilized as part of both normal physiologic and pathologic processes. Although chemical analyses do not differentiate lead isotopes, mass spectrometric determinations can differentiate the quantities of stable lead isotopes present in particular samples (e.g., lead 207, lead 206, lead 204, and lead 208). Selected geographic locations may have distinct isotopic profiles. For example, on mainland Australia the 206Pb/204Pb ratios reported in both environmental lead sources and blood samples are typically less than 17.0. By contrast, stable lead isotope profiles in blood samples of adult women immigrating from Eastern Europe and the former Soviet Union usually have 206Pb/204Pb ratios greater than 17.5 and as high as 18.5 on entry into Australia. Longitudinal monitoring of blood samples to determine stable lead isotope profiles by mass spectrometry and chemical analyses of blood samples for total lead content were conducted over a 300-day period. These data show that between 45% and 70% of lead in blood comes from long-term tissue lead stores. Recognition that the predominant source of lead in blood was tissue stores rather than the contemporaneous environment should greatly modify recommendations on use of blood lead to monitor occupational or environmental interventions. In addition, internal biokinetics of lead, documented through presence of tissue lead in blood, underlie the long-term health risks of lead exposure. Transfer of lead to the fetus from maternal tissue stores represents a special area of concern.

Adult↗
PubMed1993

Childhood injury mortality in New South Wales: geographical and socio-economic variations.

This paper reports a retrospective study of deaths due to unintentional injury in children aged between 0 and 14 years of age in New South Wales between 1985 and 1987. The aims were to determine whether the pattern of child injury mortality differed between rural and metropolitan New South Wales and to establish the relationship between socio-economic status, based on a geographical indicator of socio-economic status and child injury mortality. The child injury mortality rate for New South Wales in 1985-87 was 12.3 deaths per 100,000 population per year. The rate in the country area of 15.3 deaths per 100,000 was significantly higher than that for the metropolitan area of 11.3 per 100,000 (P < 0.05). Deaths of passengers in motor vehicle traffic accidents (P < 0.01) and deaths due to fires (P < 0.01) were greater in the country area. A negative linear association between socio-economic status and child injury mortality was found in the Sydney metropolitan area (P < 0.01). This trend was most apparent for deaths of child pedestrians (P < 0.01).

Accidents↗
PubMed1989

Injury surveillance: a key to effective control of childhood injuries.

Injuries account for 50% of deaths in Australian children aged 1-14 years, and are a major cause of hospital admission and disability. Injury surveillance systems involving the establishment of ongoing, systematic collection and analysis of data relevant to injury prevention and trauma management have a critical role in the effective control of the injury pandemic. Contemporary Australian initiatives including the establishment of the National Injury Surveillance and Prevention Project, new national public health programmes and research initiatives have the potential to establish a new wave of injury control programmes on a firm scientific base.

Accident Prevention↗
PubMed1988

Child accident-mortality in the Northern Territory, 1978-1985.

The mortality in children who were aged 0-14 years in the Northern Territory in 1983-1985 was 2.5-times higher than it was for Australia generally over the same period. Total accidental-death rates over the period 1979-1983 in Aboriginal children were 2.2-times higher than in non-Aboriginal children. A trend towards an excess in Aboriginal child mortality was present in most categories except drowning and was particularly noteworthy for deaths due to natural and environmental causes (predominantly caused by box-jellyfish stings). Non-Aboriginal children experienced higher rates of death due to drowning than they did elsewhere in Australia; most of these occurred in domestic swimming-pools. A higher mortality was encountered in rural areas. The pattern of motor-vehicle-related deaths differed between Aboriginal children and non-Aboriginal children, with the former experiencing a greater number of deaths due to non-collision accidents that involved "loss of control". The implications of these findings for the development of appropriate preventive strategies is discussed.

Accidents↗
PubMed1986

The case for scoliosis screening in Australian adolescents.

A survey of 3660 Year 10 students, with an average age of 15 years, was carried out in a random sample of Adelaide secondary schools to determine the prevalence of structural scoliosis and the need for implementing a programme of scoliosis screening. By means of the Forward Bending Test and a specially devised scoring system 144 (3.9%) children were found to have signs that were suggestive of scoliosis; all but 12 were assessed subsequently by standardized clinical and radiological examinations. One hundred and three children were found to have structural scoliosis of 5 degrees or more; this represented a prevalence of 3.1%. The prevalence in girls (4.3%) was significantly higher than in boys (1.9%), and girls tended to have more severe curves and require treatment more frequently. Only one third (34) of the cases of structural scoliosis had been detected before this survey; most (28) of these had been detected through an earlier, subsequently discontinued, school screening programme. This study concludes that screening for scoliosis by means of a scored Forward Bending Test should be carried out in South Australian schools for all students in Year 8 and for girls in Year 10. The policy of screening boys in Year 8 should be the subject of further research. An educational programme for health professionals, parents, students and physical education teachers should support the programme.

Adolescent↗