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Biomedical subjects

W Ferguson

Publications and source records attributed to W Ferguson.

18 recordsLinked to original sources
PubMed2000

Automated measurement of unsaturated iron binding capacity is an effective screening strategy for C282Y homozygous haemochromatosis.

BACKGROUND: C282Y hereditary haemochromatosis is an appropriate condition for population screening. Transferrin saturation, the best screening test to date, is relatively expensive, labour intensive, and cannot be automated. Unsaturated iron binding capacity is a surrogate marker of transferrin saturation and its measurement can be automated. AIMS: To evaluate a screening strategy for C282Y hereditary haemochromatosis in a tertiary hospital environment based on unsaturated iron binding capacity as the initial screening test. METHODS: Measurement of unsaturated iron binding capacity was adapted to the main laboratory analyser. An unsaturated iron binding capacity of less than 30 micromol/l was identified as an appropriate decision point and 5182 consecutive subjects were screened over 28 consecutive days. RESULTS: Of those screened, 697 had an unsaturated iron binding capacity less than 30 micromol/l. Of these, transferrin saturation was greater than 40% in 294. A total of 227 were able to be genotyped for the C282Y mutation. Nine subjects homozygous for C282Y were identified. Based on full cost recovery, affected persons were identified at a cost of Aus$2268.77 per case (approximately US$1496). CONCLUSION: Automated measurement of unsaturated iron binding capacity enables a cost effective, large scale population screening programme for C282Y hereditary haemochromatosis to be developed.

Adult↗
PubMed1999

Discordant detection of monosomy 7 by GTG-banding and FISH in a patient with Shwachman-Diamond syndrome without evidence of myelodysplastic syndrome or acute myelogenous leukemia.

The myelodysplastic syndromes (MDS) are a group of hematologic disorders commonly affecting elderly persons and often leading to acute myelogenous leukemia (AML). Although rare in children, when MDS does occur, it is frequently part of a congenital disorder such as Shwachman-Diamond syndrome (SDS). Monosomy 7 and/or deletion of part or all of 7q are poor prognostic signs in MDS and AML, although the pathophysiologic relationship between this finding and MDS or AML is unclear. Shwachman-Diamond syndrome is an inherited illness characterized by exocrine pancreatic insufficiency and by congenital neutropenia. Patients with SDS are at increased risk of developing myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML). Because monosomy 7 is a poor prognostic sign in MDS and AML, establishing its presence is important. However, different methods of detection of monosomy 7 may lead to different results in some patients. We present the case of a 10-year-old girl known to have SDS, who had a bone marrow aspiration and biopsy done to rule out MDS and AML. By light microscopy, the patient's bone marrow was unremarkable. GTG-banding showed the following karyotype: 45,XX,-C[3]/47,XX,+C[1]/46,XX[45]. Fluorescence in situ hybridization (FISH) was performed with a chromosome 7-specific alpha-satellite probe (D7Z1). Almost all (373 of 376) cells exhibited only one chromosome 7 signal. A second marrow aspiration done 6 months later showed an essentially normal karyotype by GTG-banding. Fluorescence in situ hybridization with the same chromosome 7 probe showed 230 of 250 cells to be monosomic for chromosome 7. A whole chromosome 7 painting probe demonstrated disomy for chromosome 7 in 90 of 90 cells; however, subtle heteromorphism in the centromeric regions of the 2 copies of chromosome 7 was noted in some cells. This case demonstrates that FISH and GTG-banding can give discordant results, that the two should be viewed as complementary technologies, and that both have a place in a full karyotypic analysis. Furthermore, this case demonstrates for the first time that heteromorphism and/or subtle structural abnormalities of chromosome 7, previously associated with MDS and AML, can exist without clinical or morphologic signs of these illnesses. It will be of interest to further study the relationship, if any, between SDS and various structural abnormalities of chromosome 7 in MDS and AML, and to elucidate the molecular mechanisms of pathogenesis, physiology, and treatment of these disorders.

Bone Marrow↗
PubMed1988

Development of pulmonary vascular response to oxygen.

The ability of the pulmonary circulation of the fetal lamb to respond to a rise in oxygen tension was studied from 94 to 146 days of gestation. The unanesthetized ewe breathed room air at normal atmospheric pressure, followed by 100% oxygen at three atmospheres absolute pressure in a hyperbaric chamber. In eleven near-term lambs (132 to 146 days of gestation), fetal arterial oxygen tension (PaO2) increased from 25 +/- 1 to 55 +/- 6 Torr (mean +/- SE), which increased the proportion of right ventricular output distributed to the fetal lungs from 8 +/- 1 to 59 +/- 5%. In five very immature lambs (94 to 101 days of gestation), fetal PaO2 increased from 27 +/- 1 to 174 +/- 70 Torr, but the proportion of right ventricular output distributed to the lung did not change, 8 +/- 1 to 9 +/- 1%. In five of the near-term lambs, pulmonary blood flow was measured. It increased from 34 +/- 3 to 298 +/- 35 ml.kg fetal wt-1.min-1, an 8.8-fold increase. We conclude that the pulmonary circulation of the fetal lamb does not respond to an increase in oxygen tension before 101 days of gestation; however, near term an increase in oxygen tension alone can induce the entire increase in pulmonary blood flow that normally occurs after the onset of breathing at birth.

Animals↗
PubMed1987

The relative merits of various methods of indirect measurement of intraabdominal pressure as a guide to closure of abdominal wall defects.

Visceral ischemia secondary to increased intraabdominal pressure (IAP) following closure of abdominal wall defects presents a serious postoperative problem. Currently, the method of closure and postoperative management are determined by clinical impressions rather than measurement of IAP. In this study various methods of indirectly measuring IAP were compared in 17 rabbits in which IAP was sequentially increased with an intraabdominal balloon. Vesical and inferior vena caval (IVC) pressures were found to have good statistical correlation with IAP. Other methods tested were gastric, rectal, superior vena caval, femoral and brachial artery, and rectus compartment pressures. All were found to be poor indicators of actual IAP. In nine of the rabbits, radiolabeled microspheres were used to assess cardiac output and visceral blood flow. Renal blood flow was very sensitive to increased IAP with dramatic impairment at IAP above 10 to 15 mmHg. Small intestinal flow was less sensitive and did not become significantly diminished until IAP exceeded 25 to 30 mmHg. Our studies suggest that vesical and IVC pressure monitoring should be used to evaluate IAP in the clinical setting. If IAP is in excess of 10 to 15 mmHg surgical intervention is indicated to prevent the development of renal ischemia.

Abdominal Muscles↗
PubMed1986

Rabbit tissue composition: developmental aspects of tissue fluid and fractional exclusion of albumin.

The maturational changes in tissue water spaces and in the fractional exclusion of albumin from the interstitial gel were studied in the developing rabbit using multiple radioactive tracers. Total tissue water and extracellular water decrease with age in all organs studied. Intracellular water decreases in the heart and brain, transiently increases in the muscle, and is unchanged in the ileum and lung. However, the percentage of extravascular water located in the cell increases with age in all organs. Fractional exclusion of albumin is unchanged in the muscle and brain, fluctuates in the lung, increases in the ileum, and decreases in the heart. Possible mechanisms for regional differences in fluid and albumin changes with maturation are discussed. Until the role of the fractional exclusion of albumin in the interstitial matrix in the maintenance of tissue fluid balance is elucidated, the physiological impact of these developmental changes will not be evident.

Age Factors↗
PubMed1979

Burke stroke time-oriented profile (BUSTOP): an overview of patient function.

A simple multidisciplinary time-oriented computer-compatible functional profile is described for the quantitative assessment of stroke patients and their progress during rehabilitation. The reasons for developing a new rating scale as well as the implications for computer analysis of the data collected are discussed.

Activities of Daily Living↗
PubMed1978

The contingent negative variation in antisocial behaviour: a pilot study of Broadmoor patients.

Using a classical click/flash paradigm, the CNV was recorded from the following three groups of subjects at Broadmoor Hospital: (1) 14 'psychopathic' patients selected by use of the 4/9 MMPI profile and confirmed by independent clinical diagnosis; (2) 15 'non psychopathic' patients, all psychotic and mainly schizophrenic; (3) 14 healthy staff control subjects. All three groups were matched for age and sex; the two patients groups were also matched for length of stay. Two series of 32 paired stimuli were used, separated by an interval of 30 minutes. The mean CNV voltage was significantly lower in the 'non-psychopathic' patients. The amplitude of the 'psychopath's' CNV response did not differ significantly from that of the staff controls, but the response variability between the first and second series of trials was much greater in the 'psychopathic' patients than in the other two subject groups. The 'psychopathic' subjects tended to show more rapid initial development of the CNV.

Adult↗