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Biomedical subjects

Z X Chen

Publications and source records attributed to Z X Chen.

At least 55 records · Page 3Linked to original sources
PubMed1989

Heterogenous response of primary cultured bone marrow cells of patients with different varieties of leukemia to differentiation inducers.

The in vitro induced differentiation of a number of human leukemia cell lines by chemical inducers not only provides a valuable model system for the study on the mechanism of hematopoietic cell proliferation and differentiation at both cellular and molecular levels, but also reveals a new prospect in the treatment of leukemia. In order to find out the possibility of applying inducing agents to the patients with various types of leukemia, the bone marrow cells in primary culture from 50 patients with leukemia were tested for their inducibility in response to the inducers. Only M3 leukemia bone marrow cells can be markedly induced by retinoic acid to the myeloid terminal cells with positive NBT reduction while the cells of other types respond with uncertainty. TPA is able to cause a macrophage-like differentiation in bone marrow cells of all types of leukemia except M1. However, the leukemic cells of chronic myelogenous leukemia in lymphocytic blast crisis will lose response to TPA. The cultured bone marrow cells of acute lymphocytic leukemia respond neither to retinoic acid nor to TPA. Homoharringtonine, a chemotherapeutic drug used in the so-called HOAP regimen for acute nonlymphocytic leukemia, seems to possess the capability of inducing HL-60, the promyelocytic leukemia cell line, to NBT positive myeloid terminal cells, although the inducing effect is weaker than retinoic acid.

Adolescent↗
PubMed1989

[Synovial chondromatosis].

24 cases of synovial chondromatosis were examined including 16 males and 8 females of 22-64 yrs of age. The lesions were located in the knee (16), hip (4) and elbow (4) joints. All cases were treated surgically. The number of cartilaginous nodules and joint mice removed from each joint ranged from 2 to 689. The authors emphasize that the diagnosis could not be definitely established unless multiple foci of cartilaginous metaplasia were found in biopsy of the synovial membrane and that complete removal of cartilaginous nodules and joint mice was essential for successful treatment. Since the disorder is self-limiting, local synovectomy is adequate in most cases and total or subtotal synovectomy is indicated only in cases with extensive synovial membrane involvement. If the synovial membrane is normal, simple removal of joint mice is enough.

Adult↗
PubMed1989

[Effects of nebulized distilled water on tracheal reaction in asthmatic patients].

To investigate the mechanism of bronchial spasm induced by inhalation of ultrasonically nebulised distilled water (UNDW) ultrasonically nebulised solutions including hypoosmolar (distilled water, 0.3% NaCL) isoosmolar (0.9% NaCL) and hyperosmolar solutions (2.7% NaCL, 3.6% NaCL, 4.6% KCL 22.2% dextrose) were used for challenge test in 12 asthmatic patients and 10 healthy subjects as controls. The dose of solution required to induce a 20% reduction in FEV 1 (FD 20-FEV 1) was recorded. In another 10 asthmatic patients, a challenge with UNDW was conducted after pretreatment with sodium cromoglycate (SC), Ipratropine Bromide (IB) to investigate the protective effect of the two medicines. The results showed that distilled water and three hyperosmolar solutions which were of the same osmotic pressure (3.6% NaCL, 4.6% KCL and 22.2% dextrose) were most potent in inducing bronchoconstriction, and no significant difference in PD 20-FEV 1 was found among them 0.3% and 2.7% NaCL were next and 0.9% NaCL was the least potent. Normal subjects showed no response to the solutions. The SC gave significant protection to nine of the ten patients, and IB gave it to five of the ten. Our results indicate that a change in the osmolarity of the fluid lining the respiratory tract may be an important determinant of the airway response; sodium cromoglycate which inhibits the mediator release of mast cell can reduce the airway response to UNDW.

Adolescent↗
PubMed1989

[A survey on Campylobacter jejuni high infection in a nursery].

An epidemiologic survey on Campylobacter jejuni infection in a nursery was made in April 1987. It was found that there was a spread of C. jejuni high infection. Two cooks affected by enteritis of C. jejuni were considered to be a reservoir of the infection. Stool cultures were positive for C. jejuni in 43 out of 187 children, with a positive rate of 23%. Eight of the 43 had diarrhea and the others were asymptomatic carriers (24.3%). Controls were set up in another nursery with 238 healthy children and 201 non-diarrheal outpatients; C. jejuni was positive for 11.4% and 7.5%, respectively. The difference was quite significant (P less than 0.005). Results of biotyping on the strains isolated from the two cooks and the children in the nursery showed that all were of C. jejuni biotype 1, except two (4.7%) of the strains from the children, which were E. coli. The authors have suggested that transmission of C. jejuni in the nursery may be caused by contaminated food or person-to-person contact.

Adult↗
PubMed1989

[Survey of Campylobacter jejuni/coli infection and risk factors in children].

From March to May 1987, 798 children under 7 years of the outpatients in Chengdu district were examined and their stool samples cultured for Campylobacter jejuni/coli. C. jejuni/coli was isolated from 31 (9.51%) of 326 children with diarrhea and 22 (4.66%) of 472 children with non-diarrhea. The difference was significant (P less than 0.05). This result indicated that C. jejuni/coli is an important pathogen of children diarrhea in Chengdu district. Meanwhile, by inquiry we investigated risk factors related with C. jejuni/coli infections. Case group was consisted of 53 children with C. jejuni/coli positive. For each case, 3 controls were chosen from 745 children with C. jejuni/coli negative and matched according to age (less than 6 month), sex, living place (city or countryside), way of feeding, and whether to have diarrhea or not. The results has shown that contact with animals a week before being ill and habit of intake of food with hands are risk factors of C. jejuni/coli infection of childhood in Chengdu, with an odd ratio of 2.97 and 2.71 respectively. This provides valuable information about the prevention of C. jejuni/coli infection.

Campylobacter Infections↗
PubMed1988

Reduced CO2/O2 specificity of ribulose-bisphosphate carboxylase/oxygenase in a temperature-sensitive chloroplast mutant of Chlamydomonas.

The Chlamydomonas reinhardtii chloroplast mutant 68-4PP is phenotypically indistinguishable from wild type at 25 degrees C but fails to grow photosynthetically at 35 degrees C. It had about 30% of the wild-type level of ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) holoenzyme and carboxylase activity when grown at 25 degrees C, but less than 15% when grown at 35 degrees C. Pulse-labeling with 35S showed that the decrease in enzyme level at the restrictive temperature was not a result of reduced synthesis of enzyme subunits. The CO2/O2 specificity factor (VCKO/VOKC, where VC and VO are Vmax values for carboxylation and oxygenation and KC and KO are Km values for CO2 and O2) of the mutant enzyme was found to be significantly less than that of the wild-type enzyme (54 +/- 2 and 62 +/- 1, respectively), and this alteration was accompanied by increases in KO and KC and a decrease in VC/VO. DNA sequencing revealed a single missense mutation in the 68-4PP chloroplast large-subunit gene. This mutation causes leucine to be replaced by phenylalanine at position 290 in the large-subunit polypeptide sequence. These results (i) support previous studies that implicated this region of the large subunit as an important structural component of the enzyme's function and (ii) demonstrate that chloroplast genetic modification of the CO2/O2 specificity factor of a plant-type carboxylase/oxygenase is feasible.

Carbon Dioxide↗
PubMed1988

Metabolic products of microorganisms. 243. Pyridazomycin, a new antifungal antibiotic produced by Streptomyces violaceoniger.

Pyridazomycin, a new antifungal antibiotic produced by Streptomyces violaceoniger sp. griseofuscus (strain Tü 2557), was detected in a selective screening against Mucor hiemalis (Tü 179/180). The amino acid side chain of 1 can be seen as L-ornithine, whose gamma-nitrogen atom is part of a pyridazine ring building a quaternary ammonium system. The structure of 1 was established by spectroscopic analysis of the parent compound and degradation products. The occurrence of a pyridazine ring in microbial secondary metabolites is unique.

Antifungal Agents↗
PubMed1987

[Reactivity of monoclonal antibodies ALT-01 and ALT-04 and identification of lung cancer-associated antigens].

Two IgG1 type monoclonal antibodies ALT-01 and ALT-04 were prepared by two different immunization schedules. ALT-01 was generated by fusing murine myeloma NS-1 cells with splenocytes from a BALB/c mouse immunized by human lung squamous carcinoma cells, which were coated by antisera to mixed human lymphocytes. For preparation of ALT-04, human lung squamous carcinoma xenograft-bearing nude mice were injected I. P. with the spleen cells of normal BALB/c mice in order to acquire immunofunction. The spleen cells from these tumor-bearing nude mice were fused with NS-1 cells. Then, these hybridomas were screened and cloned for 3 times. Two antibodies were shown to recognize the surface antigen on human lung carcinoma cells and several kinds of tumor cell lines but not those on normal cell lines. ALT-01 reacted to neither human lung carcinoma tissue nor its xenograft. ALT-04 reacted to human lung carcinoma tissue, of which, reaction to adenocarcinoma was the strongest but not to various normal tissues. Immunoprecipitation followed by SDS-polyacrylamide gel electrophoresis and autoradiography was used to detect the associated antigen in 35S-labeled human lung carcinoma cells. Antigens, reacting to ALT-01, show one band of Mr 38,000 but those to ALT-04 reveal two bands of Mr 48,000 and 36,000.

Animals↗
PubMed1987

[Radioimmunodetection of human lung cancer xenografts by isotope labeling monoclonal antibody ALT-04 in nude mice].

Three nude mouse models bearing the human lung cancer were established from two fresh surgical specimens and one cell line. Tumor histological structure and cell morphology were similar before and after transplantation. The monoclonal antibody ALT-04 (McAb ALT-04) against human lung cancer was labeled by 125I, 131I and 201Tl. Radioimmunodetection study showed that all the three kinds of xenografts in nude mice were specifically located by McAb ALT-04. Imaging examination confirmed the ability of isotope labeling McAb ALT-04 to detect the presence of transplanted human lung cancer tissues without the aid of background subtraction manipulations. It is suggested that McAb ALT-04 have the possibility of locating in the tumor diagnosis and guiding in the treatment.

Animals↗
PubMed1987

[Treatment of male breast cancer].

From Mar. 1958 through 1985, 50 male patients with breast cancer were treated in our hospital. The ratio of male and female with primary breast cancer was 1:90 during the same period. All were proven by pathology except one case. Forty seven have been followed for more than 5 years. There were 12 stage I lesions, 19 stage II and 16 stage III. Radical mastectomy was performed in 22 patients, total mastectomy in 11 and lobectomy in 12, supplemented by radiotherapy, chemotherapy, hormonal therapy or their combination. Two were not indicated for surgery and were only given a combination combination therapy without operation. The irradiation after radical mastectomy was to deliver to the regional lymph nodes and for the rest, a dose of 5,000-6,000 cGy/5-6 weeks should be added to the chest wall. The chemotherapy, including Thio-TEPA, 5-fluorouracil, cyclophosphamide and methotrexate etc, in the form of single or multi-drug for 1-3 courses, was given. The overall 5 and 10 year survival rates were 51% and 22.5%. The 5 year survival rates of stage I, II and III patients were 83%, 53% and 25%. The 5 year survivals of radical mastectomy, total mastectomy and lobectomy combined with radiotherapy, chemotherapy and hormonal therapy were 59%, 27% and 67%. In those who failed, 50% developed local recurrence or regional metastasis or both and 60% had extensive dissemination. The results indicate that the combination therapy comprising radical mastectomy and lobectomy has a good prognosis. The authors believe that the male breast cancer is more hormone-dependent than the female breast cancer, orchiectomy plays an important role in the treatment of advanced lesions.

Adenocarcinoma↗
PubMed1986

Radiation therapy of giant cell tumor of bone: analysis of 35 patients.

This paper reports 35 patients treated for giant cell tumor of bone. Ten patients were treated by surgery followed by postoperative irradiation. All 10 were cured; eight have survived for more than 5 years and four for more than 10 years without recurrence. Twenty-five patients were treated by radiation alone. All patients were followed for 2 to 17 years. For those who received more than 3500 rad, the local control rate was 82% (14/17); for those who received more than 4000 rad, the local control rate was 85% (11/13). Thirteen have lived for more than 5 years and nine have lived for more than 10. Our experience reveals that surgery and postoperative radiation produce the best results, and that these results are better than those reported in the literature. The results of radiation alone are comparable to that of surgery. For lesions not amenable to surgery, or those which would become crippling if surgery is attempted, radiation should be used either alone or in combination with conservative surgery. The dose for radiation alone should be 5000 to 6000 rad and for postoperative radiation, 3000 to 4000 rad. Supervoltage X rays (60Co or 8 Mv X ray), but not orthovoltage X rays, are indicated. A single radiation course with higher dose is preferred to multiple courses with lower doses. In 62% (15/24) of patients, pain relief begins before treatment is completed. In 74% (14/19) of patients, the tumor mass will not resolve until the sixth month after radiation.

Adolescent↗