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Biomedical subjects

Z N Zhang

Publications and source records attributed to Z N Zhang.

At least 19 recordsLinked to original sources
PubMed1992

Daphnetin: a novel antimalarial agent with in vitro and in vivo activity.

Daphnetin is a dihydroxycoumarin that is being used in China for the treatment of coagulation disorders. It is also a chelator and an antioxidant. In vitro, daphnetin causes a 50% inhibition (IC50) of 3H-hypoxanthine incorporation by Plasmodium falciparum at concentrations between 25 and 40 microM. Several related compounds, such as scopoletin, 2, 3-dihydroxybenzoic acid and 3, 4-dihydroxybenzoic acid show no inhibitory activity. The antimalarial activity of daphnetin is inhibited by the addition of iron. Daphnetin does not appear to be an oxidant drug, since it does not spontaneously generate superoxide in vitro. However, it does alkylate bovine serum albumin when incubated in the presence of iron. In vivo, daphnetin significantly prolongs survival of P. yoelli-infected mice.

Animals↗
PubMed1992

[Degree of cellular proliferation in the first-time bone marrow smear and its significance in the diagnosis of aplastic anemia].

According to the cellularity in the first bone marrow aspirate, 541 cases of aplastic anemia (AA) diagnosed in the Peking Union Medical College Hospital were divided into two groups--hypoplastic and hyperplastic. Comparison of the transformation, remission and long-term survival rates in the two groups showed the following results. (1) Transformation: In the hypoplastic group, 60% of the cases maintained the original degree of proliferation, 34% was transformed to hyperplastic, 3% had repeated transformation and 3% became leukemic. In the hyperplastic group, 44% maintained the original degree of proliferation, 44% was transformed to hypoplastic, 9.3% had repeated transformation and 2.7% became leukemic. (2) Remission rate: The total remission rate was 15.9% in the hypoplastic and 14.6% in the hyperplastic group. (3) Long-term survival rate: The 1-, 5- and 10-year survival rates were 70.43%, 57.66% and 51.51% in the hypoplastic group, while they were 86.7%, 71.24% and 63.34% respectively in the hyperplastic with statistical significance (P less than 0.01). It is emphasized that AA can not be ruled out if there is hyperplasia in the bone marrow smear taken for the first time or in several smears taken from the same site. Smears taken periodically from different sites are essential for correct diagnosis.

Anemia, Aplastic↗
PubMed1991

[Report of 10 cases of multiple myeloma surviving more than 6 years].

Ten cases of multiple myeloma seen in PUMC hospital survived more than six years. 4 of them survived more than ten years. 6 patients were of IgA type. Features of those cases included: (1) symptoms mild; (2) incidence of anemia low; (3) percentage of tumor cell in bone marrow also relatively low; (4) blood urea nitrogen, creatinine and calcium normal; (5) maintenance therapy rather long. The prognostic factors and the current general situation of treatment were briefly discussed.

Adult↗
PubMed1991

[Leukemia and solid tumor].

3 cases of leukemia after solid tumor and 2 cases of solid tumors after leukemia were reported. The features of leukemia after solid tumor and the relationship between the solid tumor and leukemia, as well as the possible pathogenetic factors of the secondary malignancies were discussed.

Adult↗
PubMed1991

[Clinical features of paroxysmal nocturnal hemoglobinuria (PNH) in China as compared with those in United Kingdom].

The clinical features of 26 patients of PNH in Sheffield Blood Centre, UK and 50 cases in our hospital, observed in the same period, were compared. Each case was analysed according to the same criteria, and then comparison was made between the two groups. Results showed that in our group: male patients were more common; patients usually had mild or moderate bleeding tendency; the appearance of hemoglobinuria was delayed; abdominal pain was mostly related to hemoglobinuria but not thrombosis; pancytopenia was encountered more frequently and leucopenia as well as thrombocytopenia more remarkable; the incidence of thrombosis was not rare, but occurred rather late: thrombosis was mainly seen in superficial veins, but not veins of viscera; the major cause of death was not thromboembolism but infection. About 25% of the patients achieved long term clinical remission in both groups. None of the patients in these two series transformed to myeloproliferative disorders including acute leukemia. PNH can be considered a benign and chronic hematologic disease.

Adolescent↗
PubMed1990

Influence of latent iron deficiency on generation of oxygen species in polymorphonuclear leucocytes.

Measurement of luminol-dependent chemiluminescence (CL) was employed to estimate the generation of reactive oxygen species (ROS) in polymorphonuclear leukocytes (PMN) in patients with latent iron deficiency. There were no differences in the resting value of PMN CL among 20 patients with iron deficient erythropoiesis (2.92 + 0.38 number of pulses) and 20 normal controls (3.07 + 0.52; P greater than 0.05), but a significant decrease of peak value of PMN CL was observed in patients (45.82 + 7.41) as compared with controls (76.08 + 10.12; P less than 0.01). CL production by PMN in 6 patients with storage iron depletion was similar to that of 6 healthy controls. As a good correlation was found between the peak value of PMN CL and free erythrocyte protoporphyrin (FEP) level, increase of FEP could serve as a clinical indicator in the evaluation of decrease of ROS generation in PMN of patients with iron deficiency. Oral iron supplementation could effectively improve the impaired PMN ROS generation.

Adult↗
PubMed1990

[Hemochromatosis: a review of 22 Chinese cases].

22 cases of hemochromatosis were analysed. 19 cases were collected from Chinese medical journals and 3 from our hospital. We showed the similarities and differences between Chinese and western patients. The diagnosis, mode of heredity, possible pathogenesis and management of idiopathic hemochromatosis were also briefly discussed.

Adult↗
PubMed1989

[Pharmacological deaggregation of platelet aggregation].

Antagonists of increasing concentrations were added to PRP which had exhibited irreversible aggregation and the extent of deaggregation was determined. Several classes of platelet antagonists with different mechanisms have been undertaken to reverse platelet aggregation induced by ADP, collagen, arachidonic acid, U46619 and PAF. The results indicate that maintenance of platelet aggregation is a complex phenomenon involving multiple mechanisms which depend on agonists. Maintenance of ADP induced aggregation requires exogenous calcium and active intracellular calcium mobilization. Active intracellular calcium mobilization appears to be essential for maintaining aggregation by PAF, U46619 and arachidonic acid. But additional pathway may be operative in maintaining collagen-induced aggregation. Calmodulin inhibitors with multiple actions are effective deaggregators. Calmodulin plays a role in maintaining platelet aggregation. The present study indicates that the ability of various antagonists to reverse platelet aggregation is closely related to three factors: 1) agonists used to stimulate platelet, 2) the time period following the initiation of platelet aggregation and 3) the kinds of antagonists used.

Calcium↗
PubMed1988

Treatment of longitudinal injuries in avascular area of meniscus in dogs by trephination.

A study promoting the healing of longitudinal injuries in an avascular area of the meniscus in 21 male dogs is reported. One horizontal hole from the peripheral vasculature to one of the artificial longitudinal injuries to both medial menisci of the knee in each dog was made with a needlelike trephine. The knee joints were not immobilized and the samples were taken 2, 4, 8, 12, and 24 weeks, respectively, after the operation. [3H]Thymidine was injected into the joint cavity 72 h before the sample was taken. Healed lengths were measured, and pathologic examinations and autoradiography were performed. The results showed that all of the injuries treated with trephination were partly or totally healed whereas those in controls were not healed at all, suggesting that trephination may be the procedure of choice for clinic orthopedists dealing with such injuries. By the 8th week, the healed length stopped increasing, the scar tissue began to mature, and the DNA synthesis of the fibroblasts in the granulation tissue and the fibrochondrocytes in the trephined meniscus reduced. It is thought that the fibrochondrocyte of the meniscus and the fibroblast in the granulation might be capable of obtaining the thymidine directly from the synovia of knee joint for their DNA metabolism. Multiplication of the fibrochondrocyte in the injured meniscus was also found.

Animals↗
PubMed1987

Chronic lymphocytic leukemia in China.

Chronic lymphocytic leukemia (CLL) is a very common form of leukemia among middle-aged and elderly persons in Western countries. In the Japanese, or in those with Japanese ancestry born and living in the USA, CLL is rather rare. It is also rare in China, but convincing data to support this statement are found primarily in the Chinese literature. We have reviewed previously unpublished data from Peking Union Medical College (PUMC) concerning the frequency of CLL among adult patients with the four common types of leukemia. Of 4,174 such patients (1952-1986), 4.6% had CLL; 22.9% chronic myeloid leukemia (CML); 50.3% acute myeloid leukemia (AML); and 22.3% acute lymphoblastic leukemia (ALL). This low frequency of CLL is none the less higher than that found in a multiinstitutional collection of Chinese patients with leukemia. Various clinical and laboratory aspects of a carefully studied, previously published group of patients with CLL from PUMC were compared to similar published findings in patients from the University of Utah. No differences in the overall nature of the disease were detected between these groups. However, not unexpectedly, the duration of symptoms before the diagnosis was made longer in Chinese than in USA patients and the proportion diagnosed at a time when no CLL related symptoms had been noted was less in Chinese. Neither differences in life span in the two populations nor an excess of CML, AML, and ALL at the expense of CLL were viable hypotheses to explain the rarity of CLL in China. We suggest that the dearth of CLL in Chinese is on a genetic basis, as it is thought to be in the Japanese.

Adult↗
PubMed1986

Suture and immobilization of acute peripheral injuries of the meniscus in rabbits.

A comparative study of suturing or nonsuturing with or without immobilization of acute peripheral injuries to the medial meniscus of rabbits is reported. Artificial injuries to both knees of 44 male China Blue-Violet rabbits were sutured or left unsutured. One knee joint of each rabbit was immobilized postoperatively for 6 weeks. The maximum breaking strength was measured, pathologic examinations were performed, and healed areas were measured. The results showed that there was greater healed area, higher maximum breaking strength, earlier matured scar tissue formation, and more regular fiber alignment in the treatment groups with simple immobilization of the knee joint. These results were superior to suturing plus immobilization, suggesting that external immobilization of the knee joint is the key to the treatment of acute peripheral injuries of the meniscus. It may be the procedure of choice for clinical orthopedists dealing with such injuries. The measurement of the meniscus healed area and maximum breaking strength and the use of new material with this method of immobilization were introduced by the authors.

Acute Disease↗