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Biomedical subjects

D Goh

Publications and source records attributed to D Goh.

At least 19 recordsLinked to original sources
PubMed2003

Unintentional home injury in preschool-aged children: looking for the key--an exploration of the inter-relationship and relative importance of potential risk factors.

OBJECTIVE: To investigate the physical, social and psychological environment of families with preschool-age children to identify the most significant risk factors for unintentional injury. DESIGN: A 1-year prospective case-control study, using a health-visitor-administered questionnaire. SETTING: East and Midlothian, Scotland. SUBJECTS: Seventy-nine children under 5 years of age presenting to an accident and emergency (A&E) department during 1998-1999 with an unintentional home injury and 128 matched controls. RESULTS: Of 264 families, 207 responded (78.4% response rate). The main carers of cases had a lower level of educational attainment than controls (P<0.01). This factor explained the case carer leaving fulltime education earlier, being less likely to be married and more often in receipt of government benefits. Cases lived in households with larger numbers of children, were more likely to have a physical illness, were less likely to have had a non-medically attended injury in the previous year (P<0.01) but more likely to have had another A&E injury attendance. Case households had lower electrical socket cover utilization (P<0.01) and fewer thought their child had adequate access to safe play areas. The main carers of cases tended to have a more negative life event experience in the preceding 6 months, but showed no significant differences in physical or mental well-being or social support. Cases seemed to be slightly more deprived members of their community. CONCLUSIONS: The main carer's educational attainment and socket cover utilization were lower in case families. These risk factors could be used to target families for injury-prevention work. Initiatives to raise educational achievement in the general population could lead to reductions in childhood injuries.

Accidents, Home↗
PubMed1999

Regulation of lymphotoxin production by the p21ras-raf-MEK-ERK cascade in PHA/PMA-stimulated Jurkat cells.

Although the production of lymphotoxin (LT) from activated Th1 lymphocytes has been reported extensively, the intracellular signaling mechanisms that regulate this T cell function remain totally undefined. We have examined whether the p21ras-raf-1-mitogen-activated protein kinase/extracellular signal-regulated protein kinase (ERK) kinase (MEK)-ERK cascade plays a role in regulating the production of LT, because the activity of these signaling molecules is up-regulated in activated T lymphocytes. Transfection of Jurkat leukemic T cells with a dominant negative mutant of p21ras (ras17N or ras15A), raf-1 (raf 1-130), or ERK1 (Erk1-K71R) resulted in the suppression of the mitogen/phorbol ester-stimulated production/secretion of LT. This suppression was accompanied by a parallel inhibition of mitogen-stimulated ERK activation. The selective antagonist of MEK1 activation, PD98059, also attenuated the mitogen-stimulated or anti-CD3 Ab and phorbol ester-stimulated production of LT from Jurkat cells or peripheral blood T lymphocytes. This study provides, for the first time, direct evidence that the p21ras-raf-MEK-ERK cascade plays a vital role in regulating the production of LT.

Amino Acid Sequence↗
PubMed1999

Resurgence of measles in Singapore: profile of hospital cases.

OBJECTIVE: To ascertain the profile of cases of measles seen at a general hospital during a recent outbreak that occurred despite a measles vaccination program. METHODOLOGY: A retrospective study from January 1991 to March 1998. All patients with measles (ICD code 055. 9) seen at the emergency unit or as inpatients were included. RESULTS: There were 87 cases identified. The diagnosis was clinical in all and proven serologically in 71%. Eighty-five per cent of the cases occurred between January 1997 and March 1998. There was a bi-modal age distribution with peaks in the very young (</= 18 months) and those aged 16-20 years. The majority was unvaccinated (58/87). A proportion (11/87) demonstrated vaccine failure, most likely primary failures. CONCLUSION: This changing measles epidemiology suggests lowering of herd immunity. 'Catch up' vaccinations in July- October 1997 given to school children aged 12-18 years (200 000 individuals or 82% of cohort), may have helped contain the outbreak. These results substantiated the need for a two-dose policy and 'catch-up' immunization program.

Adolescent↗
PubMed1997

Cytochrome P450 (CYP)9A1 in Heliothis virescens: the first member of a new CYP family.

A novel cytochrome P450 cDNA with its complete coding sequence and part or all of the 3' (77 nucleotides) and 5' (87 nucleotides) non-coding sequence was isolated from the tobacco budworm, Heliothis virescens (F). The 1763 nucleotide sequence encodes a protein of 532 amino acids which includes a hydrophobic N-terminal region and the highly conserved heme binding regions typical of P450s. Low sequence similarity to other P450 sequences and the presence of a thromboxane synthase-like insertion upstream from the I helix resulted in its assignment as the first member of family 9, i.e. CYP9A1. CYP9A1 is most similar to CYP3A1 from the rat (34.7% identity), but is also similar to the insect P450s from family 6, including CYP6B1v1 from Papilio polyxenes (33.3%), CYP6A2A from Drosophila melanogaster (32.4%), CYP6A3 from Musca domestica (31.7%) and CYP6B2 from Helicoverpa armigera (30.1%). Comparative Western and Northern blot studies indicate that expression of CYP9A1 in thiodicarb selected populations of tobacco budworm is associated with insecticide resistance. The pattern of restriction fragment length polymorphism (RELP) variation in offspring of single-pair matings demonstrated autosomal inheritance of CYP9A1 and enabled its assignment to linkage group 7. The coding region of CYP9A1 occupies no more than 10 kb in the tobacco budworm genome.

Amino Acid Sequence↗
PubMed1995

Intracranial pressure and cerebral arterial flow velocity indices in childhood hydrocephalus: current review.

Because of its noninvasive and repeatable nature, Doppler ultrasound has been increasingly used to assess changes in cerebral haemodynamics in infants and children with hydrocephalus. There is general agreement that a direct correlation exists between the intracranial pressure (from experimental, fontanometric and direct measurement evidence) and the resistance index. In addition, this increasing index has been predominantly due to a reduction in the end-diastolic velocity. Stable ventriculomegaly is associated with normal pulsatility. The cerebral blood flow velocity parameters change significantly following CSF drainage by tapping or shunting. The measurement of intracranial pressure and cerebral blood flow velocity are currently the best ways of assessing the need for CSF diversion and monitoring subsequent shunt function.

Blood Flow Velocity↗
PubMed1994

Psychiatric adjustment in end-stage renal disease: a follow up study of former paediatric patients.

Life-time psychiatric adjustment was studied in forty-five young adult survivors of a paediatric dialysis and transplantation programme and in a comparison group matched for age and sex. Renal patients reported more psychological problems in childhood and had lower self-esteem in adulthood, but adult lifetime psychiatric morbidity was comparable in both groups. There were differences in the pattern of psychiatric disorder with a trend for more depressive states in the renal group. Lower self-esteem was linked to early onset renal disease and to educational and social dysfunction. Results indicate relatively favourable adult adjustment of juvenile renal patients.

Adaptation, Psychological↗
PubMed1994

Oral calcium suppresses biochemical markers of bone resorption in normal men.

Calcium supplementation decreases bone resorption and retards bone loss in women. There is little information about the effects of calcium supplementation in men. The effects of a 1-g oral calcium load at 0900 on bone-related biochemical variables were evaluated in 13 normal men (aged 51-70 y). Calcium administration was associated with increases in plasma ionized calcium (P < 0.001) and urinary calcium (P < 0.001), and a decrease in plasma parathyroid hormone (P < 0.001). There was a nonsignificant trend (r = -0.47, P = 0.11) for the decrease in plasma parathyroid hormone to be related to radiocalcium absorption. After the calcium load there were decreases in the urinary hydroxyproline-creatinine ratio from 11 +/- 1.1 to 7.9 +/- 0.6 (P < 0.01), the urinary deoxypyridinoline-creatinine ratio from 14.0 +/- 1.8 to 10.1 +/- 0.9 (P < 0.05), and the urinary pyridinoline-creatinine ratio from 52 +/- 5 to 40 +/- 3 (P < 0.01) between baseline and 6 h. There was no change in plasma osteocalcin. These observations indicate that a 1-g calcium load suppresses biochemical markers of bone resorption for > or = 6 h in normal men and support the concept that calcium supplementation may be useful in the prevention of bone loss in men.

Absorption↗
PubMed1994

Neutrophil migration inhibitory properties of polyunsaturated fatty acids. The role of fatty acid structure, metabolism, and possible second messenger systems.

The n-3 polyunsaturated fatty acids (PUFA) appear to have antiinflammatory properties that can be partly explained by their biological activity on leukocytes. Since leukocyte emigration is an essential component of the inflammatory response, we have examined the effects of the n-3 PUFA (eicosapentaenoic and docosahexaenoic acids) on neutrophil random and chemotactic movement. Preexposure of neutrophils for 15-30 min to 1-10 micrograms/ml PUFA reduced the random and chemotactic migration to both FMLP- and fungi-activated complement. The inhibitory effect diminished with increasing saturation and carbon chain length, and methylation abolished this activity. Arachidonic and docosahexaenoic acids were the most active fatty acids. The PUFA concentration required to inhibit migration was dependent on cell number, suggesting that the fatty acid effects on leukocyte migration in vivo may be governed by the stage of the inflammatory response. It was concluded that the PUFA rather than their metabolites were responsible for the inhibition since: (a) antioxidants did not prevent the PUFA-induced migration inhibition and the hydroxylated intermediates were less active, and (b) inhibitors of the cyclooxygenase and lipoxygenase pathways were without effect. Inhibitors of protein kinases and calmodulin-dependent enzyme system did not prevent the PUFA-induced migration inhibition, which was also independent of phospholipase D-catalyzed hydrolysis of phospholipids. It is also shown that PUFA decrease the FMLP-induced Ca2+ mobilization.

Calcium↗
PubMed1994

The changing pattern of children's dialysis and transplantation over 20 years.

The changing treatment and outcome for children with chronic renal failure (CRF) requiring renal replacement therapy (RRT) was assessed in children referred to the only paediatric unit in the North West Region of England between 1968 and 1988. There were 108 children. Referrals in consecutive 5-year time periods increased from 9 to 41 over the 20 years with the overall incidence of new referrals less than 15 years old reaching 8.5 per million childhood population in 1983-87, whilst the proportion of children under 5-years increased from 0% to 22%. The survival rate was better in those commencing RRT in the later years: 5-year survival 56% for the 1968-72 cohort vs 88% for 1978-82. The increasing number of referrals particularly among young children, coupled with improved survival rates have considerable implications when determining the provision of care for children with ESRD.

Adolescent↗
PubMed1993

Psychosocial adjustment of adult survivors of a paediatric dialysis and transplant programme.

The social adjustment of 45 young adult renal patients who commenced treatment for end stage renal disease (ESRD) as children and of 48 age and sex matched controls were compared. Renal patients were less socially mature than controls. More lived with their parents, fewer had an intimate relationship outside the family, they had fewer school qualifications, and there was more unemployment among them. The majority, however, were in employment and the level of subjective stress and support derived from most of these areas was comparable in renal patients and in controls. Having a close relationship with a member of the opposite sex was the only domain in which renal patients reported more stress than controls. Early start of illness and current health problems were associated with poorer social outcome. A lifelong history of ESRD leads to suboptimal or delayed social functioning on conventional indicators. However this does not lead to increased overall distress in the patients about their social circumstances and quality of life does not appear to be substantially impaired.

Adaptation, Psychological↗
PubMed1993

Cerebral blood flow velocity monitoring in pyogenic meningitis.

Transcranial Doppler ultrasound monitoring of cerebral blood flow velocity (CBFV) was performed on 17 children (age range 8 days to 6 years) with pyogenic meningitis. Serial measurements of the peak systolic, end diastolic, mean flow velocity, and resistance index (equal to peak systolic velocity minus end diastolic velocity divided by peak systolic velocity) were obtained over the period of their hospital admission. In all 16 survivors there was a significant decrease in the final resistance index compared with the initial resistance index due to a significant increase in the end diastolic velocity. There was a significant increase in the final mean flow velocity. In four patients the decrease in intracranial pressure and increase in cerebral perfusion pressure after mannitol infusions was accompanied by a corresponding decrease in resistance index and increase in mean flow velocity. A pressure passive CBFV response with a significant linear correlation for resistance index/mean arterial pressure may suggest a loss of cerebrovascular autoregulation. These results suggest that in the early phase increased cerebrovascular resistance may contribute to a relative impairment of cerebral perfusion. Non-invasive monitoring by transcranial Doppler ultrasound may be helpful for early detection of deterioration in cerebral haemodynamic trends.

Blood Flow Velocity↗
PubMed1992

Cerebrovascular resistive index assessed by duplex Doppler sonography and its relationship to intracranial pressure in infantile hydrocephalus.

Duplex Doppler sonography and direct intracranial pressure (ICP) measurement were performed on 18 patients with infantile hydrocephalus. ICP was measured through a frontal reservoir or ventricular tap using a nondisplacement pressure transducer. The Pourcelot Resistive Index, RI = (peak systolic-end diastolic)/peak systolic velocity was obtained from pulsed-wave Doppler measurements of blood flow velocity in the anterior (ACA) and/or the middle cerebral (MCA) arteries. There was a statistically significant positive correlation between ICP and RIs in the MCA and ACA. Paired RI measurements in 7 patients with raised ICP decreased significantly from a mean of 0.90 pre-tap to 0.75 post-tap. Our results suggest that the RI provides a reliable measure of cerebrovascular resistance in hydrocephalus. Duplex Doppler ultrasonography thus is a useful noninvasive means of monitoring cerebrohaemodynamic change with simultaneous imaging of ventricular size in infantile hydrocephalus.

Blood Flow Velocity↗
PubMed1992

Cerebral blood-flow velocity and intermittent intracranial pressure elevation during sleep in hydrocephalic children.

The clinical importance of intermittent intracranial pressure (ICP) elevations during sleep in hydrocephalic children is unclear. Eight studies of continuous ICP monitoring with simultaneous cerebral blood-flow velocity (CBFV) measurements were recorded during sleep in seven hydrocephalic children aged between one and 10 years. ICP was measured directly through a frontal reservoir. There were two main patterns of CBFV change in response to raised ICP: a progressive decrease in mean flow velocity and increase in resistance index, suggesting impaired haemodynamic compensation to ICP elevation due to reduced circulatory reserve in patients with limited intracranial compliance; and an increase in mean flow velocity with raised ICP, suggesting that appropriate haemodynamic compensation with increased blood-flow can occur to maintain adequate cerebral perfusion in those with sufficient circulatory reserve. Simultaneous CBFV and ICP measurements may help to identify those with reduced circulatory reserve who are at greater risk of ischaemic insult from episodic increases in ICP.

Blood Flow Velocity↗
PubMed1991

Cerebral blood flow velocity changes after ventricular taps and ventriculoperitoneal shunting.

Transcranial Doppler ultrasonography (TCD) was performed on 14 patients with hydrocephalus (age range 1 day to 12 years old) before and after ventriculoperitoneal shunting. TCD was also performed with simultaneous intracranial pressure (ICP) measurements during ventricular taps through a reservoir in 7 patients. Measurements of the resistance index (RI) = (S-D)/S, peak systolic (S), enddiastolic (D) and time-averaged mean flow velocities were made. After ventricular taps and ventriculoperitoneal shunting there was a significant decrease in RI in all patients. This was due to a greater increase in D compared to S, which suggests a decreased distal cerebrovascular resistance. There was a significant correlation between RI and ICP in the older infants and children and in individual neonates. Successful cerebrospinal fluid diversion reduces ICP and cerebrovascular resistance, thus improving cerebral perfusion. The RI is a reliable index for serial monitoring of cerebrohaemodynamic change in patients with hydrocephalus.

Blood Flow Velocity↗