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Biomedical subjects

Z Xu

Publications and source records attributed to Z Xu.

At least 487 records · Page 27Linked to original sources
PubMed1995

Specific cleavage of two target sequences of the tobacco mosaic virus RNA by a di-component ribozyme.

Two di-component ribozymes RZ34 and RZ13, the simplest forms of multi-component ribozymes, by ligating mono-ribozymes RZ3 and RZ4 and RZ1 and RZ3 were constructed, respectively. The in vitro results indicate that each di-component ribozyme is able to cleave two different TMV transcripts, with the specificity and efficiency similar to their mono-ribozyme counterparts. Possible effects on the specificity and efficiency by temperature and the positions of the component-ribozymes in these di-component ribozymes were also studied.

Base Sequence↗
PubMed1995

China: lowering maternal mortality in Miyun County, Beijing.

In Miyun County in China the medical authorities registered an elevated maternal mortality ratio which needed to be verified in order to design corrective changes. A decision was taken in 1988 to start a project of pilot interventions in the organization of maternal health services and access for obstetric emergencies. A control and pilot area were chosen in order to test the validity of the interventions. The reduction in maternal mortality from the main complications (postpartum haemorrhage and eclampsia) was impressive and no more maternal deaths were registered in the pilot area with reference to these causes. The overall maternal mortality ratio per 100,000 live births dropped by more than 75% in the pilot area throughout the three-year implementation period. It was therefore shown that the synergistic effect of additional training of medical workers and traditional birth attendants, improved health education, the provision of easier access to emergency care services, the establishment of obstetric rescue teams at the county level, generally improved MCH services, and strengthened management capacity for high risk pregnancies were the most appropriate interventions to lower maternal mortality.

Child Health Services↗
PubMed1995

Rapid HLA-DRB1 generic typing by PCR-SSP method.

We report a simple and rapid HLA-DRB1 generic typing method, PCR-SSP, which is practical and inexpensive. We use 9 sequence-specific primers and 2 group specific primers to define the HLA-DRB1 specificities DR1, DR2, DR3, DR4, DR5, DR6, DR7, DR8, DR9 and DR10. The HLA DR3, DR5, DR6 and DR8 can be amplified by the two primers of DR3568 and DRB1. The DR6 specificity can be identified by excluding the DR3, DR5 and DR8 when the DR3568 are positive. Any individuals can be typed with some exception: the three pairs of phenotype DR3/DR3 and DR3/DR6, DR5/DR5 and DR5/DR6, DR8/DR8 and DR8/DR6 cannot be discriminated from each other. We typed 106 unrelated healthy people from Beijing locations in two weeks. We think this typing method is suitable to replace the error-prone serologic HLA-DR tests in routine clinical practice, including the prospective typing of cadaveric organ donors.

Base Sequence↗
PubMed1995

Sodium 2,3-dimercaptopropane-1-sulfonate challenge test for mercury in humans: II. Urinary mercury, porphyrins and neurobehavioral changes of dental workers in Monterrey, Mexico.

The sodium salt of 2,3-dimercaptopropane-1-sulfonic acid (DMPS) challenge test (300 mg p.o. after an 11-hr fast) was given in Monterrey, Mexico to dental and nondental personnel. Urine samples were collected and analyzed for total mercury. The mean mercury urinary excretion (+/- S.E.) for 6 hr before and 6 hr after DMPS administration for 10 dental technicians, who formulate amalgam, was 4.84 micrograms +/- 0.742 and 424.0 micrograms +/- 84.9; for 5 dentists, who use amalgam in their practice, 3.28 micrograms +/- 1.11 and 162.0 micrograms +/- 51.2; and for 13 nondental personnel, 0.783 microgram +/- 0.189 and 27.3 micrograms +/- 3.19. The urinary coproporphyrin levels before DMPS administration, which are indicative of renal mercury content, were quantitatively associated with the urinary mercury levels among the three study groups after DMPS administration. This was not so if the urinary mercury level before DMPS administration was compared with the urinary coproporphyrin concentration. The urinary mercury level after DMPS administration is a better indicator of exposure and renal mercury burden than is the mercury level measured in the urine before DMPS is given. Regression analysis showed that the coefficient of urinary mercury was statistically and adversely associated with complex attention (switching task), the perceptual motor task (symbol-digit substitution), symptoms and mood. The easily performed DMPS-mercury challenge test is useful for monitoring dental personnel for mercury vapor exposure.

Adult↗
PubMed1995

Acute gastritis associated with infection of large spiral-shaped bacteria.

We report a case of gastric colonization of large spiral-shaped bacteria in a patient with acute gastritis. Endoscopy showed an acute erosive and hemorrhagic gastroduodenitis. Histopathological examination of antral biopsies revealed intense neutrophil infiltrates with microabscesses. Numerous large spiral-shaped bacteria were seen in the Gram-stained smear of the gastric biopsy. The patient was treated with colloidal bismuth subcitrate and cimetidine. Biopsy taken after treatment showed resolution of infection and histological gastritis. The results provide further evidence that large spiral-shaped bacteria are another infective cause of acute neutrophilic gastritis in humans.

Acute Disease↗
PubMed1995

[Effect of praziquantel treatment on serum circulating soluble egg antigen-antibody complex (SEAIC) level in mice infected with Schistosoma japonicum].

Employing Capture ELISA, we determined the level of the circulating soluble egg antigen-antibody complex (SEAIC) in sera from mice infected with Schistosoma japonicum for 7 weeks and then treated the infected mice with praziquantel (100 mg/kg body weight). It was noted that the serum SEAIC level in treated mice dropped gradually after treatment. There was a significant decrease in 13 out of 15 mice in serum SEAIC levels at five weeks after treatment, OD value dropped from 0.358 +/- 0.074 to 0.165 +/- 0.049 (P < 0.01). The serum SEAIC level in 10 mice declined to disappear (OD < 0.097) by the 7th week after treatment. By contrast, no significant changes in serum SEAIC levels were found in the non-treated mice, the serum SEAIC level in the control group maintained moderately high (OD = 0.266 +/- 0.076) till the end of the observation.

Animals↗
PubMed1995

[Investigation of damage of the gastric mucosal barrier by Helicobacter pylori].

Damage of the gastric mucosal barrier by Helicobacter pylori (Hp) has been investigated with estimation of antral mucosal hexosamine and phospholipid, and the degree of pathologic changes to be also evoluted in 100 cases of chronic superficial gastritis. There are 42% of 50 cases of Hp positive patients with active gastric lesions, and significantly high than 50 cases of Hp negative patients (8%). The mean value of antral mucosal hexosamine is 30.33 mg/g in Hp positive group, while in Hp negative group, the mean value is 36.98 mg/g (P < 0.005). The mean value of antral mucosal phospholipid is 31.96 mg/g in Hp positive. While in Hp negative is 36.49 mg/g (P < 0.05). So, estimation of mucosal hexosamine and phospholipid can be represent the degree of damage of gastric mucosal barrier. Hp should be considered as causative agent to break down the gastric mucosal barrier.

Gastric Mucosa↗
PubMed1995

[Changes of collagen distribution in extrapulmonary arteries of hypoxia-induced pulmonary hypertensive rat].

Changes of collagen distribution in extrapulmonary arteries induced by hypoxia and the effects of ligustrazine (ligus) and 764-3 were investigated. Histological study showed that hypoxia could induce an increase of the medial and adventitial thickness of the pulmonary arterial trunk. An increase of type I and type III collagen fibers in pulmonary arterial trunk, particularly the increase of type III collagen fibers in adventitia of the pulmonary trunk were revealed by picrosirius-polarization methods. Ligus partially prevented the increase of type I and III collagen fibers of pulmonary arterial trunk. Electron microscopy showed that both the medial smooth muscle and adventitial fibroblasts were hypertrophic and hyperplastic, and the surrounding collagen fibers were increased.

Altitude Sickness↗
PubMed1995

[Mechanism of medical collagen for soft tissue augmentation].

This paper reports the fate of medical collagen after injected into rats. It is highly purified collagen. The persistence of it in rats is more than one year. It was found that fibroblasts and capillaries grew into the injections. Picrosirius-polarization demonstrated that the ration of type I and type III collagen changed. Fine green fibers of type III collagen were predominant at the early stage. Twelve months after implantation, most collagen fibers appeared as thick brilliant red fibers of type I collagen.

Animals↗
PubMed1995

[Hemodynamic study of distal splenorenal shunt (DSRS)].

Color-flow Doppler sonography (FDS) was used for assessing the hemodynamic changes in 8 patients undergoing distal splenorenal shunt (DSRS). Results were compared with 14 patients with portal-azygos disconnection (PAD). It was found that 3 weeks after DSRS portal venous flow (PVF) decreased by 50%, and at least in some patients the reduction of the PVF was a continuous process during the period of two years in the DSRS group. The postoperative decrease in PVF in DSRS patients was in sharp contrast to that in PAD patients (P < 0.001), hence PAD is superior to DSRS in remaining satisfactory PVF.

Adult↗
PubMed1995

[Diagnosis and management on acute coronary artery occlusion in valve replacement surgery: a report of four cases].

This paper reported four cases of acute coronary artery occlusion occurred during valve replacement procedure. Case 1 was of Marfan's syndrome who underwent Cabrol procedure. Case 2 was of congenital aortic bileaflet malformation with severe regurgitation and simple right coronary artery, who received the procedure of AVR. Both cases 3 and 4 suffered from rheumatic valve disease who were given DVR and tricuspid valve annuloplasty. All the cases had acute left coronary artery occlusion and did not revive after removal of aortic cross-clamp, which were immediately corrected by coronary bapass grafts from aortic to left descending branch with saphonous veins. All the patients successfully weaned from asistant circulation. Two cases survived. The causes of acute coronary artery occlusion were analyzed and the diagnostic methods and management introduced.

Acute Disease↗
PubMed1995

[Determination of bakuchiol in the fruit of Psoralea corylifolia L].

A GC method for the determination of bakuchiol of described. GC conditions for analysing are as follows: stationary phase: SE-30: injector temperature: 250 degrees C: column temperature: 200 degrees C and detector: FID. The linear range of this method is 0.24-2.4 micrograms and the average recovery is 98.82%, with a relative standard deviation of 1.58%. This method has been successfully used to determine the content of bakuchiol in the samples on the market in 11 different areas, the contents being 1%-7%.

Chromatography, Gas↗
PubMed1995

Biomechanical study on unilateral single-plane external fixer.

Six tibias removed from 30-40 years old males, who died in an accident for in less than 12 hours, were osteotomized at one-third supra-medium segment. They were fixed by an unilateral adjustable external fixer (UAEF), to be used as a model of external fixation of tibial fracture (MEFTF). The compression, tension, torsion, antero-posterior and lateral bending strength, and the strength for vertically extracting the pins from the tibia were determined in the MEFTF. Within a certain range of load, the correlation of strain to stress was basically a linear relationship. These data provide a theoretical basis of biomechanics for the improvement of UAEF and for early exercises of fracture patients, such as extend-bending of the joint, raising the limb and walking with a walking stick.

Adult↗