Sizing single DNA molecules.
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Bacteriophage lambda↗
Biomedical subjects
X H Guo
Publications and source records attributed to X H Guo.
Structure and sequence of the human alpha-L-iduronidase gene.
In humans, a deficiency of the lysosomal hydrolase alpha-L-iduronidase (IDUA;EC 3.2.1.76) results in the lysosomal storage of the glycosaminoglycans heparan sulfate and dermatan sulfate, thereby causing the lysosomal storage disorder mucopolysaccharidosis type I. The gene for IDUA is split into 14 exons spanning approximately 19 kb. We report the sequence of two non-contiguous segments of the IDUA gene, one 1.8-kb segment containing exons 1 and 2 and surrounding sequences and a second segment of 4.5 kb containing the last 12 exons. The potential promoter for IDUA has only GC box type consensus sequences consistent with a housekeeping promoter and is bounded by an Alu repeat sequence. The first two exons of IDUA are separated by an intron of 566 bp, then there is a large intron of approximately 13 kb, and the last 12 exons are clustered within 4.5 kb. No consensus polyadenylation signal was found in the 3' untranslated region, although two variant polyadenylation signals are proposed.
Base Sequence↗
[Effects of Salvia miltiorrhiza Bunge on isolated perfused liver and portal vein of rats].
The experiment results showed that Salvia miltiorrhiza (SMB) had a protective effect on the isolated perfused liver injured by CCl4 of rats, made the activity of GPT in perfusate of SMB group lower than that of intoxicated groups and relieved the hepato-pathohistologic lesions of SMB group as compared to the intoxicated group. SMB had no significant effects on both the activities of SGPT in vitro and the portal vein of rats.
Alanine Transaminase↗
[Obstructive sleep apnea syndrome and essential hypertension: diurnal variation of urinary catecholamines].
30 subjects of old and middle age (28 male, 2 female) with obstructive sleep apnea syndrome (OSAS) and 20 normal subjects with matchable age and body weight (14 male, 6 female) as control were studied with nocturnal polysomnography for at least 7 hours. Right arm blood pressure was determined in supine position before and after sleep. Meantime, three 8-hour urine specimens, two collected while awake and one during sleep were examined for urinary levels of epinephrine (E) and norepinephrine (NE) with fluorometric method. All OSAS subjects (mean apnea index 42.9) had significant arterial oxygen desaturation (mean 63.9%). 12/30 OSAS subjects had definit history of essential hypertension. They described that hypertension appeared months or years after the onset of sleep disorders. Before sleep the blood pressure in OSAS subjects was higher than that in controls (mean 133/90 mmHg versus 118/77 mmHg P < 0.001). After 7 hours of sleep with apnea events, the blood pressure rose to 149/100 mmHg (P < 0.001). whereas in the controls there was no change of statistic significance (mean 115/77 mmHg). A diurnal rhythm in free catecholamines excretion was apparent for both NE and E (P < 0.05) in the controls, while in OSAS there was no normal diurnal rhythm. 24-hour values of NE were remarkably higher than those in controls. It is known that up to 40% of OSAS subjects is in the population of essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
[Studies on the determination of the circulating antigen in experimental toxoplasmosis].
This paper reports on the regular pattern of growth and decline of the circulating antigen (CA) determined by I-ELISA in experimentally infected rabbits. Toxoplasma antigen was demonstratable in the circulation in 64.7% rabbits 1 day after tachyzoite inoculation and the level of the CA in sera from infected rabbits showed an increase on d4 and reached its peak level on d10-13 after inoculation but declined soon thereafter. CA was not detectable on days 60 to 90 after inoculation. The results suggest that determining CA is a useful means for diagnosing active toxoplasmosis and that I-ELISA might be a promising approach to detect CA in toxoplasmosis.
Animals↗
Small-angle neutron scattering study of the structure of protein/detergent complexes.
Small-angle neutron scattering (SANS) was used to study the structure of protein/sodium dodecylsulfate complexes. Two water soluble proteins, bovine serum albumin (BSA) and ovalbumin (OVA), were used. The protein concentration was kept constant at 1 wt %, and protein/detergent wt ratio varied between 1/1, 1/1.5, 1/2 and 1/3. Absolute intensities of SANS distributions were analyzed by a fractal model. Analyses of large Q portions of SANS distributions established that sodium dodecylsulfate (SDS) molecules bound to a protein/SDS complex form micelle-like clusters. On the other hand, analyses of small Q portions of SANS distributions clearly showed that the arrangement of micelle-like clusters resembles a fractal packing of spheres. We showed that a protein/SDS complex can be characterized by four parameters extracted from the scattering experiment, namely, the average micelle size and its aggregation number, the fractal dimension characterizing the conformation of the micellar chains, the correlation length giving the extent of the unfolded polypeptide chains, and the numbers of micelle-like clusters in the complex.
Animals↗