PubMed Health⌕ Search

Biomedical subjects

H J Sun

Publications and source records attributed to H J Sun.

6 recordsLinked to original sources
PubMed2003

Mutation spectrum and polymorphisms in ATP7B identified on direct sequencing of all exons in Chinese Han and Hui ethnic patients with Wilson's disease.

Wilson's disease (WD), an autosomal recessive copper transport disorder, usually presents with symptoms involving the liver or central nervous system. The disease is caused by a large number of mutations in the ATP7B gene comprising 21 expressed exons. Some of the mutations appear to be population specific, whereas others are found in probands from a variety of different ethnic backgrounds. This paper presents the results of screening of the ATP7B gene by means of the direct sequencing of all exons in the gene in 39 Han and one Hui ethnic Chinese patients. Nineteen novel mutations were revealed along with nine others that have been previously described; 57.5% of the mutations were located in exons 8, 13, and 12. In particular, the Arg778Leu mutation in exon 8 was found in 55% of these Chinese patients in at least one allele. Five patients were homozygotes and 17 patients were heterozygotes for Arg778Leu. The detection rate on direct sequencing of the polymerase chain reaction products of all exons of the ATP7B gene in 40 unrelated patients was 83.8% of alleles. Seventeen polymorphisms were also identified in patients and healthy controls. We first reported the presence of ATP7B mutations in Chinese Hui ethnic patients and summarize our results here along with the previously reported findings. A significant correlation between genotype and phenotype was not found in 37 homozygotes and 52 heterozygotes for Arg778Leu.

Adenosine Triphosphatases↗
PubMed2001

Escherichia coli disinfection by electrohydraulic discharges.

We study the survival of single-strain Escherichia coli colonies in aqueous media exposed to 5.5 kV, 90 kA electrohydraulic discharges (EHD). The probability of survival (Pn) of a 4 x 10(7) cfu mL(-1) E. coli population after n consecutive EHDs follows a logit distribution: In(Pn/ 100 - Pn) = 1.329 - 1.579 ln n with r2 = 0.993 that corresponds to lethal doses of LD50 = 2.2 and LD90 = 10.5 EHDs. Considering that the reactor is thoroughly mixed during each discharge and that LD50 = 0.9 values are nearly independent of E. coli concentrations in the range of 2 x 10(3) < or = E coli/cfu mL(-1) < or = 3 x 10(6), we ascribe the nonexponential Pn decay of single-strain E. coli colonies to a shielding phenomenon where inactive cells protect the successively smaller numbers of viable cells in the EHD. The qualitatively similar concentration dependence observed for survival under 254 nm of radiation, in contrast with the lower resistance of denser colonies to 20 kHz power ultrasound and the delayed onset of extracellular beta-D-galactosidase activity in bacterial populations already decimated by EHDs, support the view that UV radiation is the dominant disinfection agent generated by electrohydraulic discharges.

Escherichia coli↗
PubMed2001

Six months follow-up of patients with methamphetamine psychosis.

BACKGROUND: It has been nearly 50 years since the psychotic state caused by amphetamine was first reported. However, the prognosis of methamphetamine (MAP) psychosis and its relationship with chronic schizophrenia are still vague. Some authors preferred MAP psychosis model of schizophrenia, while other studies found difference between the two groups of patients in the aspects of negative symptoms. METHODS: In this study we followed 21 psychiatric inpatients with diagnosis of MAP psychosis. Schedule for affective disorders and schizophrenia (SADS), scale for assessment of negative symptoms (SANS) and global assessment scale (GAS) were used for evaluation of these patients during admission and six months after discharge. RESULTS: Seventeen patients were interviewed and eight of them confessed reuse of MAP. The follow-up examinations found decreased total scores of delusion and hallucination in SADS and increased GAS scores. The SANS scores of the MAP psychotic patients in this study were lower than moderate level. No significant change could be found for most SANS subcategory scores except some items. CONCLUSIONS: Most MAP psychotic patients followed in this study improved much in six months. The results of the SANS evaluation and the clinical course for six months indicated that the MAP psychosis is a psychotic disorder different from chronic schizophrenia.

Adult↗
PubMed1997

Motion processing in pigeon tectum: equiluminant chromatic mechanisms.

Recent psychophysical and neurophysiological studies have suggested that, in mammals, there are interactions between the P (colour processing) and M (motion processing) visual pathways, which were previously believed to be parallel and separate. In this study, the role colour information plays in the coding of object motion was determined in the tectofugal pathway of pigeons. The responses of motion-sensitive neurons in the tectum to moving stimuli formed by chromatic contrast were recorded extracellularly using standard single-unit recording techniques. A moving coloured object was presented on a uniform (opponent coloured) background (e.g. blue-on-yellow, red-on-green and black-on-white). Through systematically manipulation of the luminance contrast between object and background, an equiluminant condition was generated. It was found that, at chromatic equiluminance, the majority of cells maintain some level of response. The mean magnitude of the response at equiluminance was about one-third of the response at maximal contrast to the same chromatic border. These results suggest that tectal units can detect motion of a pattern defined by a pure colour contour, although the strength of output is considerably weaker than that for the movement of patterns formed by luminance contrast.

Animals↗
PubMed1992

A mammalian model of optic-flow utilization in the control of locomotion.

Gibson (1966, 1979) and Lee (1976) have described the potential usefulness of optic-flow information for the control of locomotion. One variable that might be particularly important for an animal approaching a target is time-to-collision, which Lee argues is most efficiently specified by the tau margin (the inverse of the relative rate of expansion of the target image on the retina). In humans, most empirical studies of optic flow have required perceptual judgements or have examined catching/intercepting behaviours. In animals, most studies have been strictly observational. This is particularly true for mammals, where there has been no experimental work of any kind looking at the control of locomotion. The present experiment demonstrates that the Mongolian gerbil (Meriones unguiculatus) uses time-to-collision information to control deceleration as it runs towards a target. The development of this animal model will aid investigation of the neural circuitry underlying optic flow utilization in motor control.

Animals↗