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Biomedical subjects

K Choong

Publications and source records attributed to K Choong.

9 recordsLinked to original sources
PubMed2006

Hypotonic versus isotonic saline in hospitalised children: a systematic review.

BACKGROUND: The traditional recommendations which suggest that hypotonic intravenous (i.v.) maintenance fluids are the solutions of choice in paediatric patients have not been rigorously tested in clinical trials, and may not be appropriate for all children. AIMS: To systematically review the evidence from studies evaluating the safety of administering hypotonic versus isotonic i.v. maintenance fluids in hospitalised children. METHODS DATA SOURCES: Medline (1966-2006), Embase (1980-2006), the Cochrane Library, abstract proceedings, personal files, and reference lists. Studies that compared hypotonic to isotonic maintenance solutions in children were selected. Case reports and studies in neonates or patients with a pre-existing history of hyponatraemia were excluded. RESULTS: Six studies met the selection criteria. A meta-analysis combining these studies showed that hypotonic solutions significantly increased the risk of developing acute hyponatraemia (OR 17.22; 95% CI 8.67 to 34.2), and resulted in greater patient morbidity. CONCLUSIONS: The current practice of prescribing i.v. maintenance fluids in children is based on limited clinical experimental evidence from poorly and differently designed studies, where bias could possibly raise doubt about the results. They do not provide evidence for optimal fluid and electrolyte homoeostasis in hospitalised children. This systematic review indicates potential harm with hypotonic solutions in children, which can be anticipated and avoided with isotonic solutions. No single fluid rate or composition is ideal for all children. However, isotonic or near-isotonic solutions may be more physiological, and therefore a safer choice in the acute phase of illness and perioperative period.

Adolescent↗
PubMed2004

Prenatal ethanol exposure alters the postnatal development of the spontaneous electrical activity of dopamine neurons in the ventral tegmental area.

Prenatal ethanol exposure causes a persistent reduction in the spontaneous electrical activity of dopamine (DA) neurons in the ventral tegmental area (VTA) in adult animals. Because DA neuron activity matures into adult pattern during postnatal development, it is possible that reduced activity in VTA DA neurons after prenatal ethanol exposure is caused by impaired postnatal development. This possibility was investigated in the present study using the in vivo extracellular single-unit recording and brain stimulation techniques. The results show an age-dependent decrease in the number of spontaneously active VTA DA neurons from 2 to 4 weeks of age in both the control and prenatal ethanol-exposed animals. In ethanol-exposed animals, the age-dependent decrease was more prominent after 3 weeks of age, resulting in lower numbers of spontaneously active VTA DA neurons in 4-week-old and adult animals. In both the control and ethanol-exposed animals, there were age-dependent increases in the firing rates and burst firing activity of VTA DA neurons after 2 weeks of age. Ethanol exposure led to slightly lower firing rates in 4-week-old and adult animals and did not impact the burst firing pattern in any age groups. There were no changes in axon conduction velocity and antidromic spike characteristics of VTA DA neurons. These results indicate that reduced activity of VTA DA neurons during adulthood after prenatal ethanol exposure does not begin prenatally. Instead, it is a result of impaired postnatal development manifested only when animals reach 4 weeks of age. These results suggest that early intervention may be an effective treatment strategy for attention deficit/hyperactivity disorder, a behavioral dysfunction related to the abnormalities of DA systems and often observed in children with fetal alcohol spectrum disorder.

Action Potentials↗
PubMed1993

Re-evaluating the need for hospitalization following synovectomy using Yttrium-90 silicate.

In 51 patients treated with Yttrium-90 (Y-90) synovectomy for rheumatoid (inflammatory) arthritis (IA) and OA of the knee we found that decreased retained knee activity (RKA) and increased extra-articular activity in lymph nodes and liver are more likely to be found in IA than OA and following bilateral knee injections. Joint inflammation, as assessed by radionuclide blood pool scan but not by SF white cell count, correlates with decreased RKA and increased activity in lymph nodes. Intra-articular steroid had no significant effect on retention or extra-articular uptake. Strict hospital immobilization improves RKA of Y-90 in IA but not in OA. Y-90 synovectomy in OA shows good RKA and low extra-articular uptake. We recommend strict immobilization following Y-90 synovectomy, particularly in IA patients and/or those with high joint blood flow.

Adult↗
PubMed1990

Role of bone scintigraphy in the early diagnosis of discitis.

Nine cases of recorded discitis are presented, in which scintigraphy played an important part in the diagnosis. The patients (five men (aged 21-75 years) and four women (aged 40-73 years)) had a history of back pain varying in duration from two days to three months. Final diagnosis was confirmed microbiologically (seven patients) or radiographically (two patients). Bone scintigraphy was a valuable diagnostic procedure for discitis with earlier detection than plain radiography in three patients and similar initial detection to that of third generation computed tomography. Single photon emission computed tomographic imaging increased diagnostic confidence by indicating the involvement of the adjacent vertebral bodies rather than of the pedicles or spinous processes.

Adult↗
PubMed1985

A multicentre prospective randomized controlled trial of induction of labour with an automatic closed-loop feedback controlled oxytocin infusion system.

A randomized prospective controlled trial of an automatic feed-back controlled oxytocin infusion system (AIS) for the induction of labour at term was carried out in three hospitals. In primiparae, a four-fold reduction in the total dose of oxytocin infused, for the same induction-delivery interval, was achieved with the AIS compared with standard labour ward protocols relying on midwife control of oxytocin infusion rate. In multiparae, the total dose of oxytocin infused was almost halved when the AIS was used, while the mean duration of labour was increased by 1.6 h to 7.5 h. There were no differences in the mode of delivery or Apgar scores. It is concluded that the AIS is a safe technique for induction of labour. Its use has demonstrated that term labour can be induced efficiently with a mean oxytocin infusion rate between 2.5 and 3 mU/min (max 8.8 mU/min) and a total oxytocin dose infused of less than 5 U.

Adult↗
PubMedDate not supplied

Lethal cardiac tachyarrhythmia in a patient with neonatal carnitine-acylcarnitine translocase deficiency.

Carnitine-acylcarnitine translocase (CACT) deficiency is an inherited defect of the co-transport of free and esterified carnitine across the inner mitochondrial membrane. We report a case of CACT deficiency in a newborn who died at 72 h of age from severe, intractable cardiac tachyarrhythmia, despite an improvement in his neurological and biochemical status. Postmortem examination showed marked steatosis of myocardium, liver, and kidney. In addition, electron microscopic studies showed virtually complete elimination of mitochondria from cardiomyocytes. It appears that the correction of the acute metabolic derangements in this condition may not prevent rapid progression to death, suggesting that the rhythm disturbances in CACT deficiency result from prior and ongoing accumulation of toxic metabolites, rather than from an acute metabolic derangement. Furthermore, we speculate that the choice of anti-arrhythmic agent in this patient may paradoxically have contributed to his death.

Carnitine O-Acetyltransferase↗
PubMedDate not supplied

[High frequency oscillation ventilation compared to conventional mechanical ventilation plus exogenous surfactant replacement in rabbits]

OBJECTIVES: (a) to evaluate the effect on oxygenation and ventilation of rabbits with induced surfactant depletion when they are submitted to a conventional mechanical ventilation, plus a small dose of exogenous surfactant; (b) to compare this group with another group submitted to a High Frequency Oscillation (HFO) without exogenous surfactant administration.METHODS: Twenty New Zealand White rabbits weighing (-/+ 3 kg) were anaesthetized and artificially induced to a endogenous surfactant depletion by successively lung lavage with normal saline (aliquots of 25 ml/kg) until to reach a persistent PaO(2) less than 100 mmHg when submitted to a mechanical ventilation in a pressure control mode with a target tidal volume of 10ml/kg, PEEP of 5cm H(2)O, FiO(2) 1.0, respiratory rate 30/min, and inspiratory time of 0.65 s. Then the rabbits were divided in (a) CMV+S group, submitted to a conventional mechanical ventilation plus exogenous surfactant replacement; (b) HFO group, submitted to a High Frequency Oscillation Ventilation. Arterial blood gases were measured at control period, post lung lavage, 15, 16 and 120 minutes after treatment started. The groups were compared using Student t test.RESULTS: The post lung lavage PaO(2) in both groups was lower than 50mmHg (p=0.154), increasing after 15 min of treatment to 254 mmHg (CMV+S) and 288 mmHg (HFO, p=0.626). The PaO(2) at 60 and 120 minutes were higher (p=0.001) in the HFO group (431 e 431 mmHg) when compared with the CMV+S group, which showed a progressive fall (148 e 126 mmHg). At 60 minutes of treatment, the PaCO(2) was lower (p=0.008) in the CMV+S group (29 versus 41 mmHg).CONCLUSIONS: In ARDS animal model a protect mechanical ventilation strategy as HFO by itself promotes a fast and persistent increase in the oxygenation, with superior levels than those observed in animals treated with conventional mechanical ventilation plus exogenous surfactant replacement.

Journal Article↗
PubMedDate not supplied

Juvenile myelomonocytic leukemia and Noonan syndrome.

A case of juvenile myelomonocytic leukemia (JMML, previously referred to as JCML) in a neonate with Noonan syndrome (NS) is described. The boy presented with bilateral congenital hydrothoraces, nonimmune hydrops, dysmorphic facies, persistent thrombocytopenia, and leukocytosis. The diagnosis of JMML was made on bone marrow cell culture studies. Review of the literature reveals an unusual preponderance of hematologic malignancies, in particular JMML, among patients with NS. Of 40 NS patients admitted to the authors' institution during a 10-year period, there were 4 (10%) with evidence of a monocytic proliferation, which resolved spontaneously. The authors postulate that patients with NS may have an increased incidence of myeloproliferative disorders, which in most cases appears to be benign but may be preleukemic or even lethal.

Adult↗