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Biomedical subjects

Z Chen

Publications and source records attributed to Z Chen.

At least 1,387 records · Page 77Linked to original sources
PubMed1993

[Spiral shaped bacteria in the human gastric biopsy].

Biopsy specimens from the gastric mucosa of 149 patients who underwent gastroduodenal endoscopy for upper gastrointestinal complaints were studied by light microscopy and culture. Spiral shaped bacteria were detected in four of the specimens by smears with Gram stain. The positive rate was 2.68%, but these bacteria and HP did not grow in culture. The characteristic helical morphology of the bacteria appears to be similar to that of the bacteria found in the stomach of cats and dogs. And what of significance in these cases is the presence of spiral shaped bacteria in association with chronic gastritis.

Adult↗
PubMed1993

[Molecular study of the mechanism of chromosomal translocation (15;17) in acute promyelocytic leukemia (APL)].

Molecular studies of chromosomal translocation (15;17) in acute promyelocytic leukemia (APL) have shown that retinoic acid receptor A (RARA) gene on chromosome 17 is juxtaposed to the PML gene on chromosome 15. This results in a PML-RARA chimeric gene. Our work has demonstrated that the PML breakpoints in APL patients are clustered in two limited regions, PML-bcr1 and PML-bcr2, separated from each other by about 10 kb. DNA sequence of PML-bcr1 and primary structure of the junctional region of reciprocal chromosomal translocation in a patient have been determined in this paper. Compared to those of two previously reported cases abroad, we found that the breakpoint may be situated in the topoisomerase II cleavage site. A working model has been proposed for the mechanism of DNA illegitimate recombination in t (15;17).

Base Sequence↗
PubMed1993

[Respiratory effects of tutin microinjection into NPBM of rabbits].

On sodium pentobarbital anesthetized, cervical vagotomized adult rabbits, the microinjection of 1 microliter (10 micrograms) tutin into NPBM causes reversible changes in electrical activity of the diaphragm in different degrees. The most remarkable change is the reversible apnea. Our results indicate that NPBM plays an important role in the generation or modulation of respiratory rhythm and that tutin stimulates the pontine respiratory related neurons, thus disturbs the activity of neuronal circuit involved in respiration rhythm generation or modulation.

Animals↗
PubMed1993

The study of relationships between the damage of visual function and hemorrheology, ocular rheography, as well as other related factors in patients with primary open angle glaucoma (POAG).

Researches of glaucoma visual function damage, hemorheology, ocular rheography and other related multiplex factors, with computed multifactorial stepwise regression analysis, indicate that the elevation of intraocular pressure (IOP) is not the only factor to induce visual impairment. POAG patients are shown to have markedly reduced diastolic perfusion pressure in ophthalmic artery, besides prolonged filling time of the retinal artery and vein, diminished erythrocyte deformability and increased platelet adhesion rate. The characteristic of ocular rheographic changes in POAG patients of controlled IOP suggest that the abnormal changes of hemorheology be responsible for the damage of visual function. The abnormal changes of plasma viscosity, blood apparent viscosity, blood viscoelasticity, hematocrit, mean red cell volume etc could be found in addition to the reduction of PO2, SO2% and trace elements (Cr, Zn, Mg, Fe) in patients with POAG. Computed multiply stepwise regression analysis and Bayes discrimination were made among the deteriorate rate of quantitative visual field and 28 factors from the combined investigation. Only the hemorrheological index could be introduced into the multiply regression equations. The more the damage of visual function in POAG patients, the more accurate the discriminatory effect. Based upon the results, and the reports of articles published as well as the search of 1982-1989 Compact Combridge MEDLINE Medical data base, the new clinical concept could be presented that POAG might belong to the scope of blood hyperviscosity syndromes. When IOP elevation and the decrease of ocular artery pressure existed, the damage of visual function in POAG patients should be deteriorated.

Adult↗
PubMed1993

Molecular study on the chromosome 15 breakpoints in the translocation t(15; 17) in acute promyelocytic leukemia (APL).

Chromosomal translocation t(15; 17) is a specific marker of acute promyelocytic leukemia (APL). In this study, molecular cloning of the t(15; 17) breakpoint was carried out in a Chinese APL patient. It has been shown that the retinoic acid receptor alpha (RARA) gene, normally located on chromosome 17, was fused with a new transcription unit PML, normally localized on chromosome 15. We have subsequently cloned a portion of the PML gene and generated a panel of probes. A PML gene rearrangement was detected in 33 out of 36 APL cases studied. 24 rearrangements were clustered in a 4.4 kb region, designated here as PMLbcr1 whereas 9 rearrangements were concentrated in a 6.5 kb region, defining another breakpoint cluster region (PMLbcr2). These two types of rearrangement constitute the basis for the heterogeneity of the PML-RARA fusion gene and its possible biological significance remains to be explored.

Adolescent↗
PubMed1993

[Viscoelastic property alterations in patients with rheumatic heart disease and congestive heart failure].

Few papers on alteration of whole blood viscoelastic properties in patients with congestive heart failure (CHF) have been reported. In this study viscoelastic property parameters were measured in 63 consecutive patients with rheumatic heart disease and CHF. All subjects were divided into four groups according to NYHA classification of heart function. There were 14 class I, 16 class II 20 class III and 13 class IV. Contraves low-shear-30 rheometer was used for measuring the viscoelastic parameters. The results demonstrated that there was no significant difference of these parameters between class I and class II, that the apparent viscosity, AI and eta' in class III were higher than those in class I, and that eta 0.512, eta 5.96 AI, eta', eta" and G' in class III were higher than those in class II. All viscoelastic parameters but eta p in class IV were markedly higher than those in other groups. However, there were no statistically significant difference of eta p among all subjects and nor significant difference of these parameters between male and female were noted. There was a negative correlation between viscoelastic parameters and heart function parameters by pulse Doppler echocardiography (peak flow velocity, stroke volume and cardiac output). The results also showed a significant direct correlation between eta 0.512 AI, and eta" and the heart function parameters mentioned above.

Adolescent↗
PubMed1993

[Prevention of reserpine induced experimental gastric ulcer in rat with amoxicillin a report of preliminary controlled study].

In recent years, amoxicillin (A) has been proved very effective in clearing helicobacter pylor (HP) and promoting ulcer healing. Is the cure due solely to the clearance of HP? Forty three Wistar rats were randomized into four groups to investigate the efficacy of A in preventing the experimental ulcer induced by reserpine and compare it with that of ranitidine (R) and antacid weishuping (W). A normal saline (NS) group was used as control. The total numbers of ulcer induced per rat for the NS, W, R and A groups were 7.8 +/- 5.1, 2.2 +/- 3.2, 1.0 +/- 1.2 and 2.1 +/- 1.9, respectively. The ulcer indices were 20.8 +/- 13.2, 4.5 +/- 7.7, 2.0 +/- 3.7 and 4.5 +/- 3.9, respectively. No HP was identified. The results indicated that A, R and W were all effective in preventing reserping induced ulcer with no significant difference (P > 0.05); they were significantly more effective than NS (P < 0.05). Since A is not an antacid and no HP existed in the experimental rats, there must be a mechanism of A involved in the prevention of experimental ulcer.

Amoxicillin↗
PubMed1993

[Molecular genetic analysis on six cases of sex reversal syndrome].

Southern blot hybridization using Y-specific DNA probes and electrophoretic analysis of the SRY gene fragment amplified through polymerase chain reaction (PCR) have been performed in six cases of sex reversal syndrome (three 46, XX males and three 46, XY females). The result showed that the Y-specific DNA hybridization signal and SRY sequence were absent in one XX male and present in the remaining cases. This finding indicates that testis development of this XX male was initiated in the absence of the SRY gene.

Adult↗
PubMed1993

Localization of the chromosome 15 breakpoints and expression of multiple PML-RAR alpha transcripts in acute promyelocytic leukemia: a study of 28 Chinese patients.

Translocation (15;17)(q22;q12-q21) is a chromosome aberration specifically found in acute promyelocytic leukemia (APL), that generates a chimeric gene between the promyelocytic leukemia (PML) gene on chromosome 15 and the retinoic acid receptor alpha (RARA) gene, on chromosome 17. In the course of molecular investigations of a series of 28 Chinese patients with APL, we have simultaneously used Southern blot and reverse transcriptase polymerase chain reaction (RT-PCR) analysis to characterize the PML gene breakpoints on chromosome 15 and identify PML-RARA fusion transcripts. Our results confirmed the existence of the three recently described bcr1, bcr2, and bcr3 breakpoint cluster regions. In addition, structural data provided by PML-RARA transcripts allowed us to more accurately locate the 3' borders of clusters bcr1 and bcr3. Moreover, our data suggest a preferential localization of the breakpoints within bcr1 and bcr3. The primary structure of a 1.4 kb DNA segment flanking the 5' part of the PML gene and that of the bcr3 cluster (2.1 kb) were also established.

Base Sequence↗
PubMed1993

CD38- and Leu6-positive cells in dermal lesions of mycosis fungoides.

The phenotypes of mononuclear cells in 16 patients with mycosis fungoides (MF) (8 were in tumor stage and 8 in pretumor stage) were tested by ABC immunochemical technique. The results showed that the percentage of CD38 and Leu6(+) cells in tumor stage was higher than that in pretumor stage. CD38 was identified to be a marker of the immature lymphocytes. The change of CD38 might be helpful in staging MF and predicting the prognosis of the disease. In addition, Leu6(+) cells, oval or round in shape and without dendritic processes were found in tumor stage, suggesting that they might be immature lymphoid cells. This feature needs further investigation.

ADP-ribosyl Cyclase↗
PubMed1992

An ultraviolet light-damaged DNA recognition protein absent in xeroderma pigmentosum group E cells binds selectively to pyrimidine (6-4) pyrimidone photoproducts.

The binding specificity was defined of a human ultraviolet light-damaged DNA recognition protein (UV-DRP), the activity of which is absent in some xeroderma pigmentosum complementation group E cells. Our results suggest that cyclobutane pyrimidine dimers (CPDs) are not high affinity UV-DRP binding sites--a finding consistent with other reports on this protein (Hirschfeld et al., (1990) Mol. Cell Biol., 10, 2041-2048). A major role for 6-4 photoproducts in UV-DRP binding was suggested in studies showing that irradiated oligonucleotides containing a T4C UV box sequence, which efficiently forms a TC 6-4 photoproduct, was a superior substrate for the UV-DRP when compared to a similar irradiated oligonucleotide having a T5 sequence. The latter sequence forms CPDs at a much higher frequency than 6-4 photoproducts. In a more direct approach, T4C-containing oligonucleotides complexed with the UV-DRP were separated from the unbound oligonucleotide fraction and the frequencies of 6-4 photoproducts in the two DNA populations were compared. The UV-DRP-bound fraction was highly enriched for the 6-4 lesion over the unbound fraction supporting the conclusion that 6-4 photoproducts are the principal binding cues for the UV-DRP.

Base Sequence↗