Biomedical subjects

N K Ng

Publications and source records attributed to N K Ng.

4 recordsLinked to original sources

PubMed2004

Feeding behaviour: hydrothermal vent crabs feast on sea 'snow'.

The crab Xenograpsus testudinatus lives at enormously high densities around the sulphur-rich hydrothermal vents found in shallow waters off Taiwan, even though this acidic environment is low in nutrients. Here we show that these crabs swarm out of their crevices at slack water and feed on the vast numbers of zooplankton that are killed by the vents' sulphurous plumes, and that rain down like marine 'snow'. This opportunistic feeding behaviour explains how the crabs are able to survive in the adverse toxic environment of these shallow hydrothermal vents.

Adaptation, Physiological↗

PubMed1999

Regulation of striatal dopamine release through 5-HT1 and 5-HT2 receptors.

Dopamine (DA) release in the striatum is regulated by 5-hydroxytryptamine (5-HT, serotonin) through putative heteroreceptors. However, the effect of 5-HT is controversial. The present study investigated the effects of different 5-HT receptor ligands on DA release in the rat striatum by using in vivo microdialysis in conscious and freely moving rats. Perfusion with 5-carboxamidotryptamine, anpirtoline, pindobind-5-HT1A, and isamoltane demonstrated the involvement of 5-HT1A and 5-HT1B receptors in facilitating DA release. In contrast, 5-HT2 receptors mediated inhibition of DA efflux, as shown by experiments with DOI [R-(-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane] and ketanserin. A 5-HT3 agonist (1-(m-chlorophenyl)-biguanide hydrochloride) did not have any effect. None of the agonists used affected DA uptake into striatal synaptosomes. Unilateral 6-hydroxydopamine lesioning of the nigrostriatal DA pathway led to a selective decrease in 5-HT2 receptors. It is concluded that there are 5-HT2 heteroreceptors at the dopaminergic terminals that mediate inhibition of DA release. Further investigation is required to clarify the localization of the 5-HT1 receptors in the striatum.

Animals↗

PubMed1992

Chorionic villus sampling: evaluation of obstetric performance.

Chorionic villus sampling is frequently utilised in the Nottingham region as a means of early prenatal diagnosis of genetic problems. Its relative safety in the early antenatal period is well established but there has been some concern that perinatal mortality may be greater in the chorionic villus sampling group as compared to amniocentesis. We have in response studied our own data and report the obstetric outcome in 144 cases where the pregnancy has progressed beyond 28 weeks gestation. We have selected a procedure free control group matched for parity. We have found no significant difference in the perinatal outcome and obstetric performance and conclude that at this juncture we should continue to offer our services as chorionic villus sampling offers significant advantages in the first trimester over amniocentesis.

Adult↗

PubMed1992

The role of prophylactic antibiotics in caesarean section--a randomised trial.

A prospective randomised controlled study was conducted over a 6 month period on the value of administering prophylactic antibiotics in patients undergoing emergency caesarean section at the Ipoh General Hospital. A total of 222 patients were randomised to receive 24 hours of ampicillin (500 mg per dose), cefoperazone (1 gm per dose) or no antibiotics. In all parameters of patient morbidity, the group receiving cefoperazone showed significantly better results as compared to the group not receiving antibiotics. The ampicillin group also had favourable results but generally not achieving statistical significance. Prophylactic antibiotics appear to be beneficial and consideration should be given to make it a routine in all emergency caesarean sections.

Ampicillin↗