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J Giles

Publications and source records attributed to J Giles.

At least 19 recordsLinked to original sources
PubMed2004

The timing of enteric neural crest cell colonisation of the chick embryo cloaca.

Neural crest cell (NCC) migration and formation of the enteric nervous system (ENS) is an essential process in the development of the normal human gut. Abnormalities of the ENS lead to a number of neurochristopathies. In avian embryos, the cloaca acts as a common chamber into which gastrointestinal, urinary and genital tracts emerge. Previous studies have elucidated the specific timeframes at which NCCs reach the various regions of the developing chick gut but, to date, none have looked at NCC colonisation of the cloaca. The aim of our study was to investigate the exact timing of the appearance of NCCs in the cloaca of chick embryos. Chicken embryos were harvested on embryonic days (E) 8-12. Whole embryos were fixed, embedded in paraffin and sectioned. Fluorescent immunohistochemistry, using an anti-HNK-1/N-CAM monoclonal antibody, was performed and images were obtained by confocal microscopy. There was no evidence of NCCs in the cloaca of embryos from E8 to E11. Intense immunoreactivity to HNK-1 first appeared in the cloaca of E12 embryos, demonstrating a profuse circumferential colonisation by NCCs at this time. Our study is the first to show the exact timing of enteric NCC colonisation of the chick embryo cloaca. Further studies, involving quail-chick chimeras, are required to establish the true origin of cloacal NCCs and to establish the relationship between NCCs and persistent cloaca.

Animals↗
PubMed2003

Adriamycin effects on the chick embryo.

Adriamycin is an anthracycline, anti-neoplastic drug with known teratogenic effects on foetal rats in what is known as the Adriamycin rat model (ARM). This includes conditions similar to those in newborn humans, known collectively as the VACTERL association. This comprises vertebral (V), anorectal (A), cardiac (C), tracheoesophageal (TE), renal (R) and limb (L) anomalies. We designed this study to test the hypothesis that the administration of Adriamycin to chick embryos would cause similar anomalies to those in the VACTERL association seen in the ARM. Fertilized Ross eggs received Adriamycin doses from 2-50 microg into the air sac and from 0.9-6 microg into the albumin. Administration varied from day 0-3 (D(0-3)) with D(0) being the first day of incubation. Control eggs received saline. Embryos were incubated at 38 degrees C and a relative humidity of 70%. Embryos were recovered on D(14), paraffin-embedded and transverse sections studied for morphological abnormalities. In the air sac group ( n=142), 71% of Adriamycin embryos survived versus 86% of controls (n=29). In the albumin group (n=121), 42% of Adriamycin embryos survived versus 55% of controls (n=69). No embryos demonstrated anomalies consistent with the VACTERL association. Ventral defects affected 1% of surviving Adriamycin embryos versus 4% of controls in the air sac group. In the albumin group, 19.8% of surviving Adriamycin embryos had ventral defects compared to 15.7% of surviving controls. Anophthalmia affected 1% of the surviving embryos in the Adriamycin air sac group and 2% of the Adriamycin albumin group. No controls developed anophthalmia. Exencephaly affected 2% of the survivors in the Adriamycin air sac group but none of the albumin group or controls. The administration of Adriamycin to chick embryos in comparable doses and times to those used in the ARM does not appear to produce comparable effects in relation to developmental anomalies, such as the VACTERL association. Despite examining different administration routes and mimicking the ARM, by giving Adriamycin to embryos at gastrulation, we were unable to re-create the anomalies seen in the ARM.

Abnormalities, Drug-Induced↗
PubMed2002

Quantifying relative afferent pupillary defects using a Sbisa bar.

AIM: To compare the Sbisa bar (Bagolini filter bar) with neutral density filters (NDF) in quantifying relative afferent pupillary defects (RAPD). METHODS: 11 patients with a RAPD were graded and a neutral density filter bar was used to quantify the RAPD. This was repeated using the Sbisa bar. The Sbisa bar (Bagolini filter bar) is used by orthoptists to quantify density of suppression in amblyopia and is of a similar construct to NDFs. Before this clinical part of the study the luminance for each filter was measured, which enabled a direct comparison to be made. RESULTS: In the analysis of patients with RAPD a high correlation was found when comparing the Sbisa and NDF bars r = 0.95. This was statistically significant (p = <0.001). Correlation was also high when the luminance values for the filters were substituted for the clinical readings (r = 0.92; p=<0.001). CONCLUSION: The Sbisa bar is a comparable instrument to the NDF bar in measuring RAPD. Its availability in the clinical situation makes it a practical choice.

Female↗
PubMed2001

Low dose computed tomography in suspected acute renal colic.

AIM: To evaluate whether computed tomography (CT) of the renal tract in suspected renal colic using reduced exposure factors maintains diagnostic accuracy. METHODS: Prospective multi-centre cohort study. Patients with suspected renal colic were examined using computed tomography (CT) of the renal tract followed by intravenous urography (IVU) in four different centres with five different CT systems. RESULTS: Sixty-nine patients with suspected renal colic had CT of the renal tract followed by IVU. CT was performed with reduced exposure factors, giving a mean CT effective dose of 3.5 (range 2.8-4.5) mSv compared with 1.5 mSv for IVU. Ureteric calculi were detected in 43 patients: CT and IVU detected 40 (93%) ureteric calculi. CT identified other lesions causing symptoms in five patients and identified renal calculi in 24 patients. IVU identified renal calculi in six patients and made false positive diagnosis of renal calculi in seven patients. Mean examination time for CT was 5 minutes and for IVU was 80 minutes. CONCLUSION: CT examination at reduced exposure factors maintains the diagnostic accuracy recorded in other series.

Acute Disease↗
PubMed2000

Null alleles at the Huntington disease locus: implications for diagnostics and CAG repeat instability.

PCR amplification of the CAG repeat in exon 1 of the IT15 gene is routinely undertaken to confirm a clinical diagnosis of Huntington disease (HD) and to provide predictive testing for at-risk relatives of affected individuals. Our studies have detected null alleles on the chromosome carrying the expanded repeat in three of 91 apparently unrelated HD families. Sequence analysis of these alleles has revealed the same mutation event, leading to the juxtaposition of uninterrupted CAG and CCG repeats. These data suggest that a mutation-prone region exists in the IT15 gene bounded by the CAG and CCG repeats and that caution should be exercised in designing primers that anneal to the region bounded by these repeats. Two of the HD families segregated null alleles with expanded uninterrupted CAG repeats at the lower end of the zone of reduced penetrance. The expanded repeats are meiotically unstable in these families, although this instability is within a small range of repeat lengths. The haplotypes of the disease-causing chromosomes in these two families differ, only one of which is similar to that reported previously as being specific for new HD mutations. Finally, no apparent mitotic instability of the uninterrupted CAG repeat was observed in the brain of one of the HD individuals.

Aged↗
PubMed1998

Trainee specialist: meeting the needs of service provision and career development.

A two-year modular training scheme to enable qualified speech and language therapists (SLTs) to become specialists in the field of acquired neurological disorders in adults was set up to address problems of: difficulty recruiting to senior posts; lack of opportunity for inexperienced therapists to gain experience in this field and the need for structured supervision. The paper describes how time was found to devise and implement the modular Nine Box System, the problems encountered, the advantages and disadvantages of the scheme as a whole and future developments. The scheme has potential to meet the needs of managers in creating a pool of experienced specialists to recruit to senior posts. It meets the needs of junior SLTs in providing a structured means of preparing for specialisation with guaranteed supervision.

Aphasia↗