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Biomedical subjects

L Z Zhang

Publications and source records attributed to L Z Zhang.

At least 37 records · Page 2Linked to original sources

[Gamete donation in an in vitro fertilization program].

Two cases of gamete donation in an IVF program were reported in this paper. In the first case the wife with recurrent abortions was found to have chromosomal abnormality, her karyotype was 45,XX,-14,-14 + rob (14 Q 14 Q). She became pregnant after IVF-ET with donated ova, and was delivered of a normal male baby on June 12, 1992. The baby's karyotype was normal. The blood group of both the husband and wife was O, while that of the baby was B. The baby suffered from icterus neonatorum as a result of ABO incompatibility but recovered quickly after treatment. Further DNA finger print analysis of the husband, wife and baby, combined with the history of egg donation IVF, proved the relationship of the parents with the baby. In the second case the husband's karyotype was 46,XY, t(4; 9) (4Q+; 9Q-). The wife had also history of recurrent abortions. Since 1989, the wife received sperm donation IUI 5 times in another hospital without success. IVF-ET with donated sperms was performed in November 1991 resulting in clinical pregnancy. She was delivered of a pair of twins, one male and one female on July 20, 1992. The possibilities of different types of gamete formation during meiosis in carriers of chromosomal balanced translocation were briefly discussed. Donation of oocytes could be realized only in an IVF program, which is also the only way to propagate for the family. However, IVF with donated sperms is indicated in women with blocked tubes besides the male factor or after repeated failures of other assisted reproductive technologies.

Adult↗

Possibility of targeting treatment for ischemic heart disease with liposome (II).

Studies on the isolated rat heart perfusion model have proved that perfusion with high Ca2+ (4.5 mmol/L), high K+ (8.7 mmol/L) or free radical generating system (FRGS) significantly increases myocardial uptake of liposomes. Intravenous injection of liposomes covalently combined with antibody of rat myocardial cells obviously elevates the target action of liposomes to myocardium. Liposome-carried SOD for treatment of rat myocardial ischemia-reperfusion injury is much more effective than simple SOD. The results evidence that the liposome as drug carrier for treatment of ischemic heart diseases shows a broad prospect for its clinical use.

Animals↗

Possibility of targeting treatment for ischemic heart disease with liposome (I).

This paper reports the basic research on the possibility of using targeting treatment for ischemic heart disease with liposome as drug carrier. Studies have been performed on isolated rat cardiomyocytes, or isolated perfused rat and rabbit hearts. Results show that cardiomyocytes may interact with liposome through fusion, endocytosis, adsorption and molecular exchange of phospholipid. Forms of cellular uptake of liposome depend chiefly on the physicochemical properties of liposomes. Anoxia changes the pattern of liposome uptake by cardiomyocytes and increases uptake of liposomes. Uptake of liposomes, especially of positively charged liposomes by ischemic myocardium is significantly increased. The quantity of increase of liposome uptake is in the following order: ischemia-reperfusion area > peripheral area of the infarct > non-ischemic area > infarcted area. The above results indicate that liposome as drug carrier might promote the delivery of drug into ischemic myocardium and cardiomyocytes.

Animals↗

[Plasminogen activators and plasminogen activator inhibitor type-1 in human endometrium].

Two types of plasminogen activator (PAs) are present in human endometrium, and their contents vary with the different phases of menstrual cycle, i.e. high in the proliferative phase and low in the secretory phase. In the present study by immunohistochemical technique, both uPA and tPA antigens were demonstrated in the stromal and glandular cells of the endometrium. In cell culture, tPA was released only from stromal cells and uPA only from glandular cells as determined by SDS-PAGE followed by fibrin overlay technique, but PA inhibitor type-1 (PAI-1) was secreted by both stromal and glandular cells. Furthermore, secretion of PAs from endometrial cells was enhanced by adding estradiol and markedly inhibited by progesterone in a dose dependent manner, while the PAI reacted just in the opposite way. The effect of the peptide hormones, hCG, GnRH, PRL, as well as cAMP in cell culture on the secretion of PAs and PAI was similar to that of estradiol, while forskolin demonstrated definitely more stimulative effect on tPA than uPA. Taking into account of the finding of the present study, it appears that, under hormonal control, a balance between PAs and PAI in the endometrium exists. The physiological roles of the PAs and PAI in the endometrium were discussed.

Adult↗

Radiotracer study on residues and residue distribution of zineb in plant-soil system.

In view of the widespread use of zineb on food plants and the toxicity of one of its metabolites, ETU, a study on the residues and residue distribution of zineb and ETU in plant-soil systems was carried out. The half-life values for total zineb residues on egg-plant leaves and in soil were observed to be over three and two weeks, respectively. Egg-plant skin contained higher amount of zineb residues than the fruit pulp. Washing with water greatly reduced zineb residue levels, especially those in the fruit skin. Compared with zineb, ETU is much easier to be uptaken by plants and to leach into deeper layer of soil due to its high water solubility. Therefore, attention should be paid to the contents of ETU in zineb formulations as impurity and formation of ETU in the environment.

Carbon Radioisotopes↗

Radiotracer study on mancozeb residues in tomato plants.

A study on the persistence, residues and residue distribution of mancozeb in tomato plant-soil system, as well as effects of cooking on transformation of residual mancozeb were carried out with radiotracer technique. Half-life values for total mancozeb residues on tomato leaves and in soil were observed to be 9.5 and 7.6 days, respectively. The results also suggested that mancozeb residues in soil were readily uptaken by plants and leach to soil layer as deep as 28cm within two weeks, although over 90% of the residues remained in the upper layer (0-6cm) of the soil. Translocation of the residues of mancozeb, especially the water soluble metabolites including ETU, throughout the plants could be one of the factors responsible for the contamination of tomato fruits. Deposit of sprayed mancozeb on the fruit skin was another important factor leading to the contamination of fruits. Fruit skin contained higher levels of residues than the pulp. Washing with water could remove more than 50% of the residues on the skin. It was also found that 20-30% of the residual mancozeb degraded to ETU during cooking process. The tomatoes should be washed to reduce the residues of the fungicide and ETU in food.

Autoradiography↗

Observation of frequencies of lymphocytes with micronuclei in human peripheral blood cultures from workers in a sulphuric acid factory.

Frequencies of lymphocytes with micronuclei (MNF) in human peripheral blood cultures from workers in a sulphuric acid factory (the SO2 concentrations in the workplace ranged from 0.34 mg/m3 to 11.97 mg/m3 air) were investigated. It was shown that among 40 workers, the MNF of 28 workers was more than 0.1%, and the MNF of 7 workers was greater than the upper limit of the normal range (0.2%). The mean MNF of the worker and the control group was 0.168% and 0.071%, respectively. The difference between them was statistically significant (P less than 0.001). It implies that SO2 is a clastogenic and genotoxic agent. No positive correlation between the MNF and length of service in workers has been observed. In the control population, the MNF of smokers was significantly higher than that of non-smokers (P less than 0.001).

Air Pollutants, Occupational↗

Chromosomal aberrations and sister-chromatid exchanges in lymphocytes of workers exposed to sulphur dioxide.

The frequencies of chromosomal aberrations and sister-chromatid exchanges (SCE) in peripheral blood lymphocytes of 40 workers chronically exposed to sulphur dioxide (SO2) at a sulphuric acid factory in Taiyuan City (North China), were studied. It was shown that the mean frequency of chromosomal aberrations and the mean frequency of lymphocytes with chromosomal aberrations of the SO2-exposed workers were both higher than the controls. The mean per 1000 metaphase frequencies of severe chromosomal aberration types (chromosome rings, translocations, and dicentrics) of the workers and the controls were 9.63 and 2.27, respectively. The difference between them was statistically significant (p less than 0.01). It was also shown that the mean SCEs/cell of SO2-exposed workers and non-exposed controls were 6.72 +/- 0.22/cell and 2.71 +/- 0.13/cell (p less than 0.01) respectively. SCEs/cell in 39 workers were all higher than 5, only 1 worker was 4.73. However, 41 controls were all lower than 4, only 1 control was 4.92. The difference between the worker and the control group was statistically significant. These results show that SO2 is a clastogenic and genotoxic agent. No positive correlation between the frequencies of chromosomal aberrations or SCE and length of service in the workers has been observed. No significant difference between smokers and non-smokers was found in these assays.

Cell Division↗

Follicular development, oocyte maturity and fertilization in vitro.

Forty-four infertile women in 44 cycles were stimulated by CC/hMG/hCG (39 cycles) and by CC/hCG (5 cycles) for the purpose of in vitro fertilization (IVF, 37 cases with 35 transfers) and gamete intrafallopian transfer (GIFT, 7 cases). Intraoperative ovum pick-up was performed 32-36 hours after hCG injection. Blood E2 and P levels were determined. Blood E2 was found to be proportional to the number of mature and intermediate oocytes obtained, and correlated with the number of follicles (greater than 10 mm) and the total follicular fluid volume. Altogether 213 follicles aspirated were analyzed. There was a highly significant linear correlation (r = 0.72, P less than 0.01) between the follicular diameter (X cm) on the operation day and the aspirated follicular fluid volume (FFV, Y). The equation of the line was Y = 3.8 X-4.4. The higher concentrations of follicular E2, P, FSH, LH and lower T concentration were crucial to the maturing process of oocytes. It was found that mature oocytes could be retrieved from 26.5% of the small follicles, so it is worthwhile to aspirate the small ones. The fertilization rate was much higher with the mature oocytes than the immature ones. But the morphologically mature oocytes might function differently, i.e. the mature oocytes retrieved from the small follicles or from follicles with unbalanced hormonal microenvironment usually give a low fertilization rate.

Adult↗

Umbilical and uterine artery flow velocity waveforms in normal pregnancy and pregnancy induced hypertension.

Umbilical and uterine artery Doppler studies were carried out in 113 cases of normal pregnancy and in 32 patients with pregnancy induced hypertension (PIH). The results were analyzed by calculating the systolic/diastolic (S/D) ratio. In normal pregnancy the umbilical velocity wave S/D ratio declined from 3.9 to 2.1 from 20th week to term, and the uterine wave S/D ratio remained constant between 1.8 and 1.9. In many cases of severe PIH the umbilical and uterine artery velocity wave S/D ratios were raised, indicating increased resistance to the blood flow. The changes of umbilical waveforms appeared earlier than those of the uterine arterial waveforms.

Adult↗

Laparotomy ovum pick-up and ultrasonic transvaginal ovum retrieval in an IVF program.

Different methods of ovum pick-up were used in an IVF program from January 1, 1988 to January 31, 1989. In the initial stage of the program, laparotomy ovum pick-up with surgical treatment of pelvic diseases resulted in two cases of clinical pregnancy in 1987 with full-term delivery of two healthy babies. Transvaginal ovum pick-up with a needle using an ultrasonic endovaginal transducer was started in late 1987. In 1988-1989 the transvaginal method was employed more frequently than laparotomy, and it has become a routine practice in the IVF program. The ultrasonic endovaginal approach seemed to give a low ovum recovery rate (70.99%), but the fertilization rate was high (85.10%, P less than 0.05), and the rate of embryo transfer was 89.33%. The average number of pre-embryo per transfer was 2.26. These figures were quite similar in the two groups. The ultrasonic transvaginal approach for egg retrieval was noninvasive, easily accepted by patients. We suggest that it can be done repeatedly on one patient to improve the cumulative pregnancy rate. However, the laparotomy for ovum pick-up has shown some special merits and is still indicated in some cases.

Adult↗

[A transvaginal sonographic needle-guided method of ovum pickup in a fertilization in vitro/embryo transfer program].

Methods of ovum pickup in the IVF/ET program in our hospital from January 1st 1988 to January 31st 1989, were reported. In the initial stage of the program in 1987, laparotomy follicle aspiration was used, which resulted in two cases of clinical pregnancy and full term delivery. Ovum pickup using an ultrasonic endovaginal transducer with a needle guide was introduced in the latter part of 1987. In 1988, the transvaginal method was employed more frequently than the laparotomy and has since become the routine in our program. The rate of embryo transfer and the average number of embryos transferred were quite similar in the two groups. Either method was adopted at that time according to the facilities available and the characteristic pathological conditions of our patients, of whom most had previous history of operation resulting in severe pelvic adhesions. The transvaginal ultrasonic needle guided method for egg retrieval is non-invasive, readily accepted by the patients and therefore may be done repeatedly on one patient in order to increase the cumulative pregnancy rate. However, the laparotomy (transabdominal) route for ovum pickup together with other pelvic surgeries is still indicated in some cases. The clinical pregnancy rate per transfer showed no statistical difference between the two groups.

Embryo Transfer↗

[Preovulatory human oocyte and its hormonal microenvironment in stimulated cycles].

The hormonal microenvironment of 213 follicles in 44 stimulated cycles was analysed. Mature and intermediate oocytes were found to be associated with larger follicles which contained significantly higher levels of E2, P, FSH and LH, while smaller follicles containing significantly higher T level usually gave rise to immature oocytes. The fertilization rate was higher in mature and intermediate oocytes than in immature oocytes. In this study there was no significant difference in the cleavage rate of the fertilized eggs in relation to the E2, P, T, FSH and LH concentrations in follicular fluid as well as to the contents of these hormones per follicle.

Adult↗

[Study on decocting conditions for Pueraria lobata Ohui in qiweibaizhu bage].

Taking the puerarin content---the chief constituent of Pueraria lobata---as the index in the mixed decoction of Pueraria lobata etc, we have adopted the method of orthogon al experiment to explore the best decocting conditions for Pueraria lobata. The results show that a better way to decoct Pueraria lobata is to cut the root into slices of 0.4-0.7 cm, and water 12-15 times the weight of the root and decoct for 30 minutes. It makes no big difference whether the root is soaked or not.

Drugs, Chinese Herbal↗