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Biomedical subjects

P Jardine

Publications and source records attributed to P Jardine.

18 recordsLinked to original sources
PubMed2003

Natural attenuation of trichloroethylene in fractured shale bedrock.

This paper describes one of the first well-documented field examples of natural attenuation of trichloroethylene (TCE) in groundwater in a fractured shale bedrock. The study was carried out adjacent to a former waste burial site in Waste Area Grouping 5 (WAG5) on the Oak Ridge Reservation, Oak Ridge, TN. A contaminant plume containing TCE and its daughter products were detected downgradient from the buried waste pits, with most of the contamination occurring in the upper 6 m of the bedrock. The monitoring well array consists of a 35-m-long transect of multilevel sampling wells, situated along a line between the waste pits and a seep which discharges into a small stream. Concentrations of volatile organic carbons (VOCs) were highest in the waste trenches and decreased with distance downgradient towards the seep. Sampling wells indicated the presence of overlapping plumes of TCE, cis-dichloroethylene (cDCE), vinyl chloride (VC), ethylene, ethane, and methane, with the daughter products extending further downgradient than the parent (TCE). This type of distribution suggests anaerobic biodegradation. Measurements of redox potential at the site indicated that iron-reduction, sulfate reduction, and potentially methanogensis were occurring and are conducive to dechlorination of TCE. Bacteria enrichment of groundwater samples revealed the presence of methanotrophs, methanogens, iron-reducing bacteria and sulfate-reducing bacteria, all of which have previously been implicated in anaerobic biodegradation of TCE. 16S rDNA sequence from DNA extracted from two wells were similar to sequences of organisms previously implicated in the anaerobic biodegradation of chlorinated solvents. The combined data strongly suggest that anaerobic biodegradation of the highly chlorinated compounds is occurring. Aerobic biodegradation may also be occurring in oxygenated zones, including near a seep where groundwater exits the site, or in the upper bedrock during seasonal fluctuations in water table elevation and oxygen levels.

Biodegradation, Environmental↗
PubMed2001

Chromium transport, oxidation, and adsorption in manganese-coated sand.

We examine how the processes of advection, dispersion, oxidation-reduction, and adsorption combine to affect the transport of chromium through columns packed with pyrolusite (beta-MnO2)-coated sand. We find that beta-MnO2 effectively oxidizes Cr(III) to Cr(VI) and that the extent of oxidation is sensitive to changes in pH, pore water velocity, and influent concentrations of Cr(III). Cr(III) oxidation rates, although initially high, decline well before the supply of beta-MnO2 is depleted, suggesting that a reaction product inhibits the conversion of Cr(III) to Cr(VI). Rate-limited reactions govern the weak adsorption of each chromium species, with Cr(III) adsorption varying directly with pH and Cr(VI) adsorption varying inversely with pH. The breakthrough data on chromium transport can be matched closely by calculations of a simple model that accounts for (1) advective-dispersive transport of Cr(III), Cr(VI), and dissolved oxygen, (2) first-order kinetics adsorption of the reduced and oxidized chromium species, and (3) nonlinear rate-limited oxidation of Cr(III) to Cr(VI). Our work supplements the limited database on the transport of redox-sensitive metals in porous media and provides a means for quantifying the coupled processes that contribute to this transport.

Adsorption↗
PubMed2000

Mesenteric angina complicating a mesodermal anomaly.

A child with macrocephaly-cutis marmorata developed severe abdominal pain thought to represent mesenteric angina. There were abnormalities of the aortic and mesenteric vasculature not previously reported in this condition. Angina therapy afforded amelioration of his symptoms. Mesenteric angina should be considered as a cause for abdominal pain in children with mesodermal anomalies.

Abdominal Pain↗
PubMed2000

Mutations in the laminin alpha2-chain gene in two children with early-onset muscular dystrophy.

We investigated two children who presented with delayed motor milestones. The first was a girl who was referred at 20 months because of developmental delay. She walked at 28 months and currently, aged 5 years, is independently mobile but has difficulty rising from the floor or going upstairs. The second was also a girl who presented at 6 weeks of age with hypotonia. Her motor milestones were delayed and she walked at the age of 2 years and 8 months and is currently independently mobile at the age of 3 years. Serum creatine kinase was elevated and a muscle biopsy showed dystrophic changes in both children. Immunohistochemistry of the laminin alpha2 chain of merosin was very similar in both cases: using a C-terminal antibody that recognizes an 80 kDa fragment, there was a mild reduction in expression on most fibres, while the staining with another antibody that recognizes a 300 kDa fragment showed a very marked reduction. Mutational analysis of the laminin alpha2 chain gene in the first patient showed that one of the two alleles had a de novo single nucleotide deletion at position 5702, causing a frameshift. In the other allele, we identified two point mutations present in cis; one was a G-->C transition at position +5 while the second was a T-->C transition at position +6 of the conserved donor splicing consensus sequence of introns 37 and 63, respectively. Transcription analysis of the corresponding cDNA region did not show any alternative splicing occurring as a result of these splice site mutations. Therefore, these mutations probably affect the splicing efficiency. Interestingly, the second child carried in both alleles the same two splicing consensus sequence mutations found in cis in the first patient. Our data provide further evidence that mutations in the laminin alpha2 chain gene are responsible not only for the severe form of congenital muscular dystrophy with onset at birth, but also for milder phenotypes, with later onset, in which the synthesis of a partially functional protein, or of a normal protein but in reduced quantity, is possible. The finding that these two unrelated patients had the same unusual mutation in common might suggest that this is a relatively commonly allele responsible for partial merosin deficiency in the UK.

Age of Onset↗
PubMed1997

Improved molecular diagnosis of facioscapulohumeral muscular dystrophy (FSHD): validation of the differential double digestion for FSHD.

A major advance in the molecular diagnosis of facioscapulohumeral muscular dystrophy is the recently reported elimination of confounding DNA fragments arising from homologous sequences located at 10q26. In order to evaluate the specificity and sensitivity of this important diagnostic test, we have compared a group of 130 patients fulfilling the diagnostic criteria for FSHD with 200 control subjects not known to have an increased risk of having an FSHD mutation. Among the FSHD cases the smallest BlnI/EcoRI fragment sizes ranged from 10 to > 48 kb with 94.6% (95% CI 89.2-97.8%) of cases having fragment sizes of 34 kb or less. Among the 400 chromosomes from controls the smallest BlnI/EcoRI fragment observed with the EcoRI/BlnI double restriction enzyme digest was 38 kb +/- 2 kb, suggesting a test specificity at a fragment size < 34 kb of or very near to 100% (lower 95% CI 98.2%). Test sensitivity at < 34 kb is estimated at 94.6% (95% CI 89.2-97.8%), all outliers having fragments > 38 kb. The Southern blot analysis with DNA probe p13E-11 has created a valuable molecular diagnostic test for FSHD.

Alleles↗
PubMed1995

Germinal mosaicism in facioscapulohumeral muscular dystrophy (FSHD).

Facioscapulohumeral dystrophy (FSHD) is an autosomal-dominant neuromuscular disorder with a prevalence of 1 in 20,000. The DNA marker p13E-11 (D4F104S1) detects a de novo DNA rearrangement in the majority of sporadic and FSHD cases. These rearrangements consist of deletions of multiple copies of tandem repeat (D4Z4). We have studied 34 new mutation FSHD families of which 26 showed a de novo fragment with p13E-11. In three of the remaining eight families without a de novo fragment, germinal mosaicism was noted. In each case, the proband had inherited a small EcoR1 fragment from the clinically unaffected mother; however, the hybridization signal intensity of this fragment in the mother's DNA was significantly reduced in all three families. This is the first study to describe such mosaicism in FSHD families using DNA analysis and therefore has a considerable significance for genetic counseling and prenatal diagnosis.

Adolescent↗
PubMed1994

The association between Coffin-Lowry syndrome and psychosis: a family study.

This paper discusses a family presenting with features of Coffin-Lowry syndrome, namely abnormal facies, skeletal abnormalities and mental handicap. Two of the mildly affected females had psychotic illness with predominant depressive features, and all the severely affected males had profound sensorineural deafness.

Abnormalities, Multiple↗
PubMed1993

Molecular analysis of British facioscapulohumeral dystrophy families for 4q DNA rearrangements.

Facioscapulohumeral muscular dystrophy is an important autosomal dominant neuromuscular disorder that has been localised to 4q35. We have analysed our extensive panel of 45 families with a new DNA marker p13E-11. The findings, based on multiply informative individual meioses and multipoint mapping, suggest that probe p13E-11 is the closest marker for the disorder and it is likely to be located proximal to the disease locus as are all the other present markers. In nine of the ten new mutations studied, a new smaller EcoRI fragment which was not present in either of the parents was detected, indicating that a de novo DNA rearrangement is indeed associated with the development of the disease state. However, in view of the difficulty in defining the size of over 30kb alleles and the recombinant events observed with p13E-11, we suggest that it should be used in combination with another VNTR marker until a close distal flanking marker for this condition is identified or the gene itself is isolated.

Adult↗
PubMed1984

A communication aid for the physically handicapped.

A communications aid for the severely handicapped is described. The aid is primarily intended to be mounted on an electric wheelchair and to be powered from the chair's battery. It may be operated by any two-switch input system or by more elaborate controls such as joy-sticks. The central unit of the aid is a purpose-built 8085 microcomputer, the operating program and data tables being sorted in a 2 kbyte EPROM. The input control is used to drive a cursor around an 8 X 8 letter board array, the selected alphanumeric character being output to a liquid crystal display. Up to 64 messages, each of no more than 15 characters, can be composed and stored by the user and recalled as required. The messages are stored in a 2 kbyte CMOS memory and are retained when the aid is switched off. It is a simple matter to increase the number of stored messages. The aid was designed with the needs of a particular 15 year old, athetoid child in mind and the results of his tests of the aid will be briefly discussed.

Biomedical Engineering↗