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Biomedical subjects

S J Robertson

Publications and source records attributed to S J Robertson.

At least 19 recordsLinked to original sources
PubMed2002

Dermatitis caused by physical irritants.

BACKGROUND: Although physical irritant contact dermatitis (PICD) is a common occupational dermatosis, it is one of the least well understood because of its multiple types, lack of diagnostic test, and the many mechanisms involved in its production. OBJECTIVES: To characterize the materials and mechanisms of physical irritation of the skin. METHODS: We did a retrospective analysis over the past 20 years of all patients with a diagnosis of PICD at St John's Institute of Dermatology Contact Dermatitis Clinic. RESULTS: Of the 29,000 patients who attended the clinic over the study period, 392 patients were diagnosed with PICD and of these, 335 files were analysed. CONCLUSIONS: Our findings show that PICD accounted for 1.15% of all patients attending the contact clinic over the study period. Diverse occupations and materials were implicated. The most common cause of PICD was low humidity due to air-conditioning, which caused dermatitis of the face and neck in office workers due to drying out of the skin.

Adolescent↗
PubMed2001

Magnetic resonance spectroscopy of the malignant prostate gland after radiotherapy: a histopathologic study of diagnostic validity.

PURPOSE: Accurate spatial representation of tumor clearance after conformal radiotherapy is an endpoint of clinical importance. Magnetic resonance spectroscopy (MRS) can diagnose malignancy in the untreated prostate gland through measurements of cellular metabolites. In this study we sought to describe spectral metabolic changes in prostatic tissue after radiotherapy and validate a multivariate analytic strategy (based on MRS) that could identify viable tumor. METHODS AND MATERIALS: Transrectal ultrasound-guided prostate biopsies from 35 patients were obtained 18-36 months after external beam radiotherapy. One hundred sixteen tissue specimens were subjected to 1H MRS, submitted to histopathology, and analyzed for correlation with a multivariate strategy specifically developed for biomedical spectra. RESULTS: The sensitivity and specificity of MRS in identifying a malignant biopsy were 88.9% and 92% respectively, with an overall classification accuracy of 91.4%. The diagnostic spectral regions identified by our algorithm included those due to choline, creatine, glutamine, and lipid. Citrate, an important discriminating resonance in the untreated prostate gland, was invisible in all spectra, regardless of histology. CONCLUSIONS: Although the spectral features of prostate tissue markedly change after radiotherapy, MRS combined with multivariate methods of analysis can accurately identify histologically malignant biopsies. MRS shows promise as a modality that could integrate three-dimensional measures of tumor response.

Aged↗
PubMed2001

Synaptic P2X receptors.

Over the past two years, ATP has clearly been shown to act as a co-transmitter with GABA, glycine and probably glutamate in the central nervous system. Our understanding of the ATP-gated P2X receptors is progressing rapidly, and the pharmacology, stoichiometry and subunit combinations of heteropolymeric P2X channels has been substantially elucidated.

Action Potentials↗
PubMed2001

A comparative study of metastatic renal cell carcinoma with correlation to subtype and primary tumor.

Clear cell (CRCC), papillary (PRCC) and chromophobe (CHRC) renal cell carcinoma (RCC) are the three most frequent subtypes of RCC. The rate and distribution of their metastatic lesions have not been well documented. We compared metastatic RCC according to subtype and primary tumor characteristics to better understand their behavior and to aid in the diagnosis of metastatic RCC. Pathology reports and clinical charts related to 283 CRCC, 48 PRCC and 13 CHRCC, including their respective sarcomatoid variants, were reviewed. A hundred and thirty-seven CRCC, 5 PRCC and 1 CHRCC with metastases were identified. CRCC and non-CRCC (PRCC and CHRCC) had different patterns of metastasis and primary tumor growth. CRCC metastases were predominantly distributed in lungs, bone, brain, lymph nodes, and adrenal glands. The associated primary CRCC measured 1.5 to 15 cm, were of all grades and stages, and were often associated with invasion of small or large veins. Three PRCC had regional lymph node metastases, 1 PRCC had both regional and mediastinal lymph node metastases. Bone metastasis was present in 1 case each of PRCC and CHRCC. One PRCC with metastasis solely to regional nodes measured 4 cm. The other 4 cases of PRCC with regional lymph node and/or distant metastases as well as the CHRCC with distant metastases were greater than 8 cm in diameter. In metastasizing and non-metastasizing non-CRCC, invasion of small veins was rare and invasion of renal veins was not seen. We cannot comment with any certainty on the metastatic behavior of CHRCC. In our experience, PRCC tend to loco-regional invasion with lymph node spread. They have a low potential for vascular invasion and distant metastases that likely occur only at late stages of the disease. CRCC has a propensity for vascular invasion and may be associated with distant metastasis at an early stage. Therefore, metastatic RCC at a distant location are most likely to be of CRCC origin than PRCC origin.

Adrenal Gland Neoplasms↗
PubMed2001

Differences in cytokine and chemokine responses during neurological disease induced by polytropic murine retroviruses Map to separate regions of the viral envelope gene.

Infection of the central nervous system (CNS) by several viruses can lead to upregulation of proinflammatory cytokines and chemokines. In immunocompetent adults, these molecules induce prominent inflammatory infiltrates. However, with immunosuppressive retroviruses, such as human immunodeficiency virus (HIV), little CNS inflammation is observed yet proinflammatory cytokines and chemokines are still upregulated in some patients and may mediate pathogenesis. The present study examined expression of cytokines and chemokines in brain tissue of neonatal mice infected with virulent (Fr98) and avirulent (Fr54) polytropic murine retroviruses. While both viruses infect microglia and endothelia primarily in the white matter areas of the CNS, only Fr98 induces clinical CNS disease. The pathology consists of gliosis with minimal morphological changes and no inflammation, similar to HIV. In the present experiments, mice infected with Fr98 had increased cerebellar mRNA levels of proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha), TNF-beta, and interleukin-1 alpha and chemokines macrophage inflammatory protein-1 alpha (MIP-1 alpha), MIP-1 beta, monocyte chemoattractant protein 1 (MCP-1), gamma-interferon-inducible protein 10 (IP-10), and RANTES compared to mice infected with Fr54 or mock-infected controls. The increased expression of these genes occurred prior to the development of clinical symptoms, suggesting that these cytokines and chemokines might be involved in induction of neuropathogenesis. Two separate regions of the Fr98 envelope gene are associated with neurovirulence. CNS disease associated with the N-terminal portion of the Fr98 env gene was preceded by upregulation of cytokines and chemokines. In contrast, disease associated with the central region of the Fr98 env gene showed no upregulation of cytokines or chemokines and thus did not require increased expression of these genes for disease induction.

Animals↗
PubMed2000

Public health implications of new guidelines for lead in drinking water: a case study in an area with historically high water lead levels.

Concern about the neurotoxicity of lead, particularly in infants and young children, has led to a revision of blood lead levels which are considered to involve an acceptable level of human exposure. Drinking water guidelines have also been reviewed in order to reduce this source of population exposure to lead. In the last 20 years, guidelines have been reduced from 100 to 50 to 10 microg/litre. Lead in tap water used to be a major public health problem in Glasgow because of the high prevalence of houses with lead service pipes, the low pH of the public water supply and the resulting high levels of lead in water used for public consumption. Following two separate programmes of water treatment, involving the addition of lime and, a decade later, lime supplemented with orthophosphate, it is considered that maximal measures have been taken to reduce lead exposure by chemical treatment of the water supply. Any residual problem of public exposure would require large scale replacement of lead service pipes. In anticipation of the more stringent limits for lead in drinking water, we set out to measure current lead exposure from tap water in the population of Glasgow served by the Loch Katrine water supply, to compare the current situation with 12 years previously and to assess the public health implications of different limits. The study was based on mothers of young children since maternal blood lead concentrations and the domestic water that mothers use to prepare bottle feeds are the principal sources of foetal and infant lead exposure. An estimated 17% of mothers lived in households with tap water lead concentrations of 10 microg/litre (the [WHO,] guideline) or above in 1993 compared with 49% in 1981. Mean maternal blood lead concentrations fell by 69% in 12 years. For a given water lead concentration, maternal blood lead concentrations were 67% lower. The mean maternal blood lead concentration was 3.7 microg/litre in the population at large, compared with 3.3 microg/litre in households with negligible or absent tap water lead. Nevertheless, between 63% and 76% of cases of mothers with blood lead concentrations of 10 microg/dl or above were attributable to tap water lead. The study found that maternal blood lead concentrations were well within limits currently considered safe for human health. About 15% of infants may be exposed via bottle feeds to tap water lead concentrations that exceed the WHO guideline of 10 microg/litre. In the context of the health and social problems which affect the well-being and development of infants and children in Glasgow, however, current levels of lead exposure are considered to present a relatively minor health problem.

Adult↗
PubMed2000

Primary primitive neuroectodermal tumor of the cauda equina.

Primitive neuroectodermal tumors (PNETs) are aggressive neoplasms composed predominantly of undifferentiated cells that show evidence of neural differentiation. Although their classification has been controversial, PNETs are well recognized primary tumors of both central and peripheral nervous systems. PNETs must be distinguished from other round-cell tumors, including Ewing's sarcoma, lymphoma, rhabdomyosarcoma, and small cell carcinoma. Intraspinal PNETs are rare neoplasms that are usually metastatic in origin. We describe the eighth reported primary PNET of the cauda equina that developed in a 52-year-old man with no significant medical history. The tumor was characterized by Homer-Wright rosettes and immunoreactivity for CD99, glial fibrillary acidic protein, neuron-specific enolase S100, and synaptophysin. The anatomic location of primary intrathecal PNETs is important as those arising in the spinal cord develop in the central nervous system, whereas those arising in the cauda equina develop in the peripheral nervous system. The histogenesis of intrathecal PNETs may be multifactorial.

Cauda Equina↗
PubMed1999

Ca2+ permeability and kinetics of glutamate receptors in rat medial habenula neurones: implications for purinergic transmission in this nucleus.

1. We have previously investigated P2X receptor-mediated synaptic currents in medial habenula neurones and shown that they can be calcium permeable. We now investigate the receptor properties of glutamate, the other, more abundant excitatory transmitter, to determine its receptor subtypes and their relative calcium permeability. This may have implications for the physiological role of the P2X receptors which mediate synaptic currents. 2. Using fast application of ATP, L-glutamate or kainate to nucleated patches, glutamate receptors were determined to be of the AMPA subtype but no functional P2X receptors were detected. 3. The deactivation and desensitization rates of the AMPA channel were determined to have time constants of 1.77 +/- 0.21 ms (n = 10) and 4.01 +/- 0.85 ms (n = 9) at -60 mV, respectively. AMPA receptors recovered from desensitization with two exponential components with time constants of 21.08 +/- 2.95 and 233.60 +/- 51.1 ms (n = 3). None of the deactivation or desensitization properties of the GluR channels depended on membrane potential. 4. The current-voltage relationship under different ionic conditions revealed that the GluR channel was equally permeable to Cs+ and Na+ but relatively impermeable to Ca2+ (PCa/PCs = 0.13, n = 6). 5. For both synaptic currents and somatic currents activated by fast application of L-glutamate to nucleated patches, decay time constants were similar at +/-60 mV in the presence of Mg2+ ions. Thus GluR channels appear to be of the AMPA subtype and not the NMDA subtype. 6. Thus, under the conditions of this study, neurones of the medial habenula lack functional NMDA receptors and possess AMPA receptors that have low permeability to Ca2+. We conclude that the P2X receptor-mediated synaptic currents are the only calcium-permeable fast-transmitter gated currents in these neurones which may be important for their physiological function.

Algorithms↗
PubMed1998

Mapping of a neurovirulence determinant within the envelope protein of a polytropic murine retrovirus: induction of central nervous system disease by low levels of virus.

Murine leukemia virus (MuLV) clone Fr98 is a recombinant polytropic virus that causes neurological disease characterized by ataxia in susceptible mouse strains. The envelope gene of Fr98 has been previously shown to encode at least two separate neurovirulence determinants. In the present study, the determinant encoded within the EcoRI/AvrII fragment of the envelope gene was further defined. In these experiments, neurovirulence was associated with a change from a serine to an arginine at position 195 and a glycine to an alanine at position 198 within the envelope protein. Neurovirulent and nonvirulent virus clones, which differed only at these two amino acid residues, showed no difference in the type or location of cells infected. Furthermore, equivalent levels of viral p30 capsid protein were detected in the brains of mice infected with either the neurovirulent or nonvirulent virus clones. These results were consistent with the interpretation that the envelope protein of the neurovirulent virus differed from that of the nonvirulent virus by having a greater toxic effect on central nervous system function.

Animals↗
PubMed1998

ATP and glutamate are released from separate neurones in the rat medial habenula nucleus: frequency dependence and adenosine-mediated inhibition of release.

1. ATP and glutamatergic synaptic currents were compared in slices of rat medial habenula nucleus using whole-cell patch-clamp techniques. 2. In most cells low voltage stimulation resulted in glutamatergic responses and not purinergic responses. In five cells where ATP currents could be stimulated with low voltages, wash out of glutamate antagonists did not reveal evoked glutamate currents. Spontaneous glutamate currents confirmed washout of antagonist. 3. Modulation of release probability of glutamate and ATP, assessed by changes in failure rate of synaptic currents, was compared under conditions of different stimulation frequencies and in the presence of adenosine agonists and antagonists. 4. ATP release, but not glutamate release, was shown to be modulated by increased stimulation frequency which resulted in inhibition of ATP release via A2-like adenosine receptors. A1 receptors caused inhibition of both ATP and glutamate release. 5. Endogenous adenosine inhibited glutamate release via A1 receptors but only inhibited ATP release via A2-like receptors. 6. Attempts to inhibit the degradation of ATP to adenosine did not alter the frequency dependence of the failure rate. 7. We conclude, from the direct demonstration and from the differences in pharmacology and frequency dependence of the modulation of release, that ATP and glutamate responses are due to release from separate neurones.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1998

A hidden client group? Communication impairment in hospice patients.

Retrospective research has identified communication impairment in over a quarter of hospice patients (Jackson et al. 1996) but this field has not been investigated using speech and language therapy assessments. The present study assessed a sample of 12 hospice patients using tests of verbal learning and recall, word-finding, sentence comprehension and motor speech. Eleven patients experienced difficulties in one or more areas of assessment. Possible reasons are discussed, including the effects of patients' illness and treatment and changes in mood or cognitive functioning. A role for speech and language therapy is proposed, in terms of assessment, advice and training. Further research is suggested to help establish the extent of impairment and define a role for speech and language therapy.

Aged↗
PubMed1997

Radiotherapy for localized prostate carcinoma. The correlation of pretreatment prostate specific antigen and nadir prostate specific antigen with outcome as assessed by systematic biopsy and serum prostate specific antigen.

BACKGROUND: The objective of this study was to correlate the failure pattern of localized prostate carcinoma after radiotherapy (RT) with pretreatment (preTx) PSA and post-RT nadir PSA, using systematic biopsies and serum PSA in the assessment of outcome. METHODS: From January 1990 to February 1994, 207 patients treated with external beam RT were followed prospectively with systematic transrectal ultrasound-guided biopsies and measurements of serum PSA levels. Three hundred forty-three biopsies were performed, with 4-7 samples taken per session. The distribution of T classification was as follows: 19 patients had T1b, 15 had T1c, 34 had T2a, 79 had T2b/c, 53 had T3, and 7 had T4. Median follow-up was 36 months (range, 12-70 months). Failures were categorized as biochemical (chemF) (PSA > 2.0 ng/mL and > 1 ng/ mL over nadir), local (LF) (positive biopsy and PSA > 2), and distant (DF). The Cox proportional hazards model was used for multivariate analysis (MVA). RESULTS: Overall, failures were seen in 68 of 207 patients: 20 LF, 24 DF, 7 LF + DF, and 17 chemF. In univariate analysis, failures correlated significantly with preTx PSA, post-RT nadir PSA, T classification, and Gleason's score (GS). The total failure rate was 12% for T1b, T1c, and T2a; 39% for T2b and T2c; and 60% for T3 and T4 (P < 0.0001). By evaluation with preTx PSA, at 36 months the total failure rate was 3% for preTx PSA < or = 5 ng/mL 16% for 5.1-10 ng/mL, 32% for 10.1-15 ng/mL, 42% for 15.1-20 ng/mL, 63% for 20.1-50 ng/mL, and 88% for > 50 ng/mL (P < 0.0001). By evaluation with post-RT nadir PSA, at 36 months the total failure rate was 4% for nadir PSA < or = 0.5 ng/ mL, 26% for 0.6-1 ng/mL, 33% for 1.1-2 ng/mL, and 92% for > 2 ng/mL (P < 0.0001). In MVA, nadir PSA (P < 0.0001) and T classification (P < 0.0005) were independent predictors for any failure. LF occurred in 13% of patients (27 of 207). For these 27 patients, the categorization of T classification was: T1b/T1c/T2a, 7%; T2b/T2c, 16%; and T3/T4, 15% (P = not significant). In MVA, only nadir PSA (P = 0.0004) predicted for LF. DF occurred in 15% of patients (31 of 207). In MVA, nadir PSA (P < 0.0001) and T classification (P < 0.0001) predicted for DF, with pretreatment PSA of borderline significance (P < 0.05). To assess preTx predictors of outcome, post-RT nadir PSA was removed from the model. PreTx PSA then became the dominant variable to predict any failure (P < 0.0001), LF (P = 0.05), chemF (P = 0.0001), and DF (P < 0.003), while T classification also predicted for any failure (P = 0.03), chemF (P = 0.05), and DF (P < 0.0001). CONCLUSIONS: Systematic prostate biopsies, performed as part of the rigorous followup of prostate carcinoma after RT, define the patterns of failure and confirm the prognostic value of preTx PSA, post-RT nadir PSA, and T classification. Prior to treatment, preTx PSA is the overwhelming independent predictor of failure, but it is surpassed by post-RT nadir PSA when this is added to the model.

Aged↗
PubMed1997

Evaluation of radiation effect, tumor differentiation, and prostate specific antigen staining in sequential prostate biopsies after external beam radiotherapy for patients with prostate carcinoma.

BACKGROUND: Sequential systematic biopsies after radiotherapy (RT) for prostate carcinoma were evaluated with respect to radiation effect, tumor differentiation, and prostate specific antigen (PSA) staining, and these histopathologic parameters were correlated with local outcome. METHODS: Since 1990, transrectal ultrasound-guided biopsies have been used to follow patients with localized prostate carcinoma after radical external RT at the General Hospital division of the Ottawa Regional Cancer Centre. Eighty-nine patients with residual tumor in 1 or more biopsies at 10-78 months of follow-up were selected for review. All patients had undergone biopsy on more than one occasion. The 198 biopsies were stained for PSA, high molecular weight keratin, and proliferative cell nuclear antigen (PCNA). Therapy effect was graded by nuclear and cytoplasmic changes. RESULTS: Of these 89 selected patients, 25 progressed to local failure (LF), 38 had delayed tumor clearance, and 26 remained biopsy positive without local or biochemical progression. In the 24- and 36-month biopsies, RT effect correlated with mean nadir serum PSA (Grade 4-6 RT effect: 0.7 ng/mL; Grade 0-3 RT effect: 1.3 ng/mL [P = 0.01]) and with local outcome (Grade 0-2 RT effect: 55% LF; Grade 3-4 RT effect: 30% LF; and Grade 5-6 RT effect: 0% LF [P = 0.003]). Of tumors with minimal RT effect, 61% were PCNA positive, compared with 34% for moderate and 17% for marked RT effect (P < 0.001). Adjacent areas within biopsies showed varied RT effect in 27 patients, of whom 41% had local failure, compared with 18% of patients with uniform RT effect (P = 0.03). Gleason score was assigned only if RT effect was minimal (36 patients/59 biopsies); 74% had the same Gleason score (+/-1) as the original, whereas 23% were 2 points lower. Only 1 biopsy lost PSA staining completely and 10% stained faintly, whereas 34% stained moderately and 55% strongly. CONCLUSIONS: PSA staining is apparently retained in residual tumor after RT, despite obvious RT effect. RT effect correlates with serum PSA nadir, PCNA staining, and local outcome. Varied RT effect is commonly observed in biopsies, and correlates with local failure. There is no convincing evidence for tumor dedifferentiation after RT.

Aged↗
PubMed1997

Properties of ATP receptor-mediated synaptic transmission in the rat medial habenula.

The properties of central ATP-mediated synaptic currents were studied using whole-cell patch-clamp recording in rat medial habenula slices. Release was shown to be calcium dependent with a Hill coefficient of approximately 2. The voltage dependence of synaptic current amplitudes was approximately linear. Some reduction of the synaptic current amplitudes was observed at 10 mM extracellular calcium, suggesting calcium block/permeability of the channels. This was confirmed by observation of current-voltage reversal potentials in different calcium concentrations. We estimate that the channels underlying half the synapses showed a negligible calcium permeability. In the other four out of eight synapses the results suggest a very high calcium permeability with an estimated PCa/PCs of > 10. Thus, at -70 mV, in 1 mM calcium, more than 15% of the ATP-mediated synaptic current is estimated to be carried by calcium, but only at synapses with calcium-permeable channels. Net current through these synaptic channels is also controlled by the voltage dependence of synaptic current decay time constants (increasing e-fold for 158 mV depolarization) and by a strong dependence of transmitter release on the frequency of stimulation of the presynaptic neurone, with failure rates increasing 3-fold as stimulation rates were increased from 1 to 10 Hz.

Animals↗
PubMed1997

Neurologic disease induced by polytropic murine retroviruses: neurovirulence determined by efficiency of spread to microglial cells.

Several murine leukemia viruses (MuLV) induce neurologic disease in susceptible mice. To identify features of central nervous system (CNS) infection that correlate with neurovirulence, we compared two neurovirulent MuLV, Fr98 and Fr98/SE, with a nonneurovirulent MuLV, Fr54. All three viruses utilize the polytropic receptor and are coisogenic, each containing a different envelope gene within a common genetic background. Both Fr98 and Fr98/SE induce a clinical neurologic disease characterized by hyperexcitability and ataxia yet differ in incubation period, 16 to 30 and 30 to 60 days, respectively. Fr54 infects the CNS but fails to induce clinical signs of neurologic disease. In this study, we compared the histopathology, regional virus distribution, and cell tropism in the brain, as well as the relative CNS viral burdens. All three viruses induced similar histopathologic effects, characterized by intense reactive astrogliosis and microglial activation associated with minimal vacuolar degeneration. The infected target cells for each virus consisted primarily of endothelial and microglial cells, with rare oligodendrocytes. Infection localized predominantly in white matter tracts of the cerebellum, internal capsule, and corpus callosum. The only feature that correlated with relative neurovirulence was viral burden as measured by both viral CA protein expression in cerebellar homogenates and quantification of infected cells. Interestingly, Fr54 (nonneurovirulent) and Fr98/SE (slow disease) had similar viral burdens at 3 weeks postinoculation, suggesting that they entered the brain with comparable efficiencies. However, spread of Fr98/SE within the brain thereafter exceeded that of Fr54, reaching levels of viral burden comparable to that seen for Fr98 (rapid disease) at 3 weeks. These results suggest that the determinants of neurovirulence in the envelope gene may influence the efficiency of virus spread within the brain and that a critical number of infected cells may be required for induction of clinical neurologic disease.

Animals↗
PubMed1996

Is lead in tap water still a public health problem? An observational study in Glasgow.

OBJECTIVE: To assess the relation between tap water lead and maternal blood lead concentrations and assess the exposure of infants to lead in tap water in a water supply area subjected to maximal water treatment to reduce plumbosolvency. DESIGN: Postal questionnaire survey and collection of kettle water from a representative sample of mothers; blood and further water samples were collected in a random sample of households and households with raised water lead concentrations. SETTING: Loch Katrine water supply area, Glasgow. SUBJECTS: 1812 mothers with a live infant born between October 1991 and September 1992. Blood lead concentrations were measured in 342 mothers. MAIN OUTCOME MEASURES: Mean geometric blood lead concentrations and the prevalence of raised tap water lead concentration. RESULTS: 17% of households had water lead concentration of 10 micrograms/l (48.3 nmol/l) or more in 1993 compared with 49% of households in 1981. Tap water lead remained the main correlate or raised maternal blood lead concentrations and accounted for 62% and 76% of cases of maternal blood lead concentrations above 5 and 10 micrograms/dl (0.24 and 0.48 mumol/l) respectively. The geometric mean maternal blood lead concentration was 3.65 micrograms/dl (0.18 mumol/l) in a random sample of mothers and 3.16 micrograms/dl (0.15 mumol/l) in mothers whose tap water lead concentrations were consistently below 2 micrograms/l (9.7 nmol/l). No mother in the study had a blood lead concentration above 25 micrograms/dl (1.21 mumol/l). An estimated 13% of infants were exposed via bottle feeds to tap water lead concentrations exceeding the World Health Organisation's guideline of 10 micrograms/l (48.3 nmol/l). CONCLUSIONS: Tap water lead and maternal blood led concentrations in the Loch Katrine water supply area have fallen substantially since the early 1980s. Maternal blood lead concentrations are well within limits currently considered safe for human health. Tap water lead is still a public health problem in relation to the lead exposure of bottle fed infants.

Adult↗