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Biomedical subjects

D Jiang

Publications and source records attributed to D Jiang.

At least 91 records · Page 5Linked to original sources
PubMed1999

[The clinical application of perfluorotributylamine liquid in the complicated retinal detachment].

OBJECTIVE: To evaluate the clinical application value of perfluorotributylamine liquid (PFTL) made in China in the complicated retinal detachment. METHODS: PFTL was injected into eyeball after vitreoretinal surgery, it could open funnel of retinal detachment, push subretinal fluid out from peripheral hole and flat and immobilize the posterior retinal during vitreoretinal surgery. In eyes with giant tears, PFTL could unfold and fix retinal flap. RESULTS: The retinas in all cases with giant tears were reattached, and sixty per cent in the eyes with PVR-D2-D3 reattached. In 8 eyes the visual acuity was improved. CONCLUSION: PFTL is valuable in treatment of complicated retinal detachment. It facilitates vitreoretinal surgery, obviates the potential complications.

Adolescent↗
PubMed1999

[Effects of Ganoderma lucidum (Leyss ex Fr) Karst compound on the proliferation and differentiation of K562 leukemic cells].

A series of experiments including cell culture and benzidine staining test were undertaken to investigate the effects of Ganoderma lucidum(Leyss ex Fr) Karst Compound(GLC) on the proliferation and differentiation of K562 leukemic cells. The results showed that different concentrations of GLC(from 4 mg.ml-1 to 12 mg.ml-1) could promote human bone marrow granulocyte-macrophage colony forming unit (CFU-GM) proliferation, but suppressed the growth of K562 leukemic cell colonies, and IC50 was 9.2 mg.ml-1. The data from liquid culture demonstrated that GLC could suppress K562 cells proliferation in a dose-dependent(from 4 mg.ml-1 to 20 mg.ml-1) and time-dependent(from 1-5 days) manner. K562 cells could be induced to differentiate into more mature erythrocytic cells by 4 mg.ml-1 and 8 mg.ml-1 GLC. It is concluded that GLC may be a good medicine for leukemia therapy.

Cell Differentiation↗
PubMed1999

[Analysis of 16 cases with aggressive fungal maxillary sinusitis].

OBJECTIVE: To improve the diagnosis and treatment level of aggressive fungal maxillary sinusitis. METHOD: 16 cases were diagnosed with CT. Caldwell-Luc's surgery was done in 13 cases and Lima surgery in 3 cases. None of them were treated by antifungal agents. RESULT: It showed osteolytic damage with bony defect which was different from expanded bony defect caused by benign tumor, but similar to malignant tumor. No recurrence occurred as followed from 6 months to 2 years. CONCLUSION: Computed tomography is very important in its diagnosis. Early explorative operation is useful in making definite diagnosis.

Adult↗
PubMed1999

[Best minimization to locate the brain sources of magnetic waves].

Locating the sources of brain magnetic fields is a basic question in magnetoencephalography (MEG). This question belongs to the indeterminate problem, that is, infinite solutions can be obtained from the equations of the measured small magnetic fields on the detector. Therefore a model of mathematics is needed to give more information. The major models of mathematics are the search method with many dipoles and the Lp minimum norm method. For the first model, if a global search is used, too much calculation time will be spent; if the gradient search is used, the searches usually converge to a local minimun. So other methods are introduced to find out the initial values, and then the gradient search can be used. For the second model, the depth of the brain sources will dependend on the choice of the weight functions which have several different types, and we do not know in advance which type is correct, so that it is difficult to have a good estimation of the depth of the brain sources. To overcome the difficulties, we use the method with three object functions which are the minimum Lp norm, the deviation between the calculated magnetic fields and the measured magnetic fields, and the number of the sources. This method is similar to the minimum norm method, a weight function is also introduced. But this weight function contains many reference variables which have to be determined through the minimization with three object functions. By choosing suitable weight function and its reference variables, the correct estimation of the depth of the brain sources can be achieved.

Algorithms↗
PubMed1999

[Perspectives of effect on new electrode technology with implantable motor prostheses for stimulating peripheral nerves].

This paper explores approaches to electrode technology and stimulating techniques that selectively activate specific portions of a peripheral nerve trunk with much less implanted hardware than is required with present motor prosthesis systems. The first section reviews the vulnerability of nerves to both mechanical and electrical factors and suggests ideas on how these findings might be utilized in future electrodes. The second section presents results on longitudinally oriented intrafascicular electrodes for nerve stimulation recording. The third section reviews results on longitudinal intrafascicular electrodes for nerve stimulation and recording.

Animals↗
PubMed1999

[Design of blood cell analyzers by using stationary suspending laser light scattering method].

The paper analyses the technology development of automatic blood cell analyzers, put forward the new method of blood cell counting and classification by stationary suspending laser light scattering. The new automatic blood cell analyser is designed by using this method. The design idea of the light route and data acquisition system is stressly provided in the paper. The calibration is performed by using the standard blood cell particulate.

Adult↗
PubMed1998

Autocrine transforming growth factor alpha provides a growth advantage to malignant cells by facilitating re-entry into the cell cycle from suboptimal growth states.

CBS human colon carcinoma cells are poorly tumorigenic in athymic nude mice, whereas FET colon carcinoma cells are non-tumorigenic. Both cell lines have well differentiated properties in tissue culture. Transforming growth factor alpha (TGF-alpha) was ectopically expressed by stable transfection of a TGF-alpha cDNA under repressible tetracycline control. The TGF-alpha-transfected cells showed enhanced clonal initiation and shortened lag phase growth in tissue culture without an alteration in doubling time in exponential phase relative to untransfected cells. Furthermore, the TGF-alpha transfectants showed increased independence from exogenous growth factors in clonal growth assays and induction of DNA synthesis after release from quiescence. Growth factor independence was associated with sustained epidermal growth factor receptor activation in quiescent TGF-alpha-transfected cells and the requirement of exogenous insulin for stimulation of quiescent cells to re-enter the cell cycle. Higher cloning, reduced lag time in tissue, and the acquisition of growth factor independence for DNA synthesis without a change in doubling time of TGF-alpha-transfected cells indicate that autocrine TGF-alpha functions by facilitating re-entry into the cell cycle from sub-optimal growth states rather than promoting or controlling the proliferation of actively cycling cells. The modulation of growth regulation by autocrine TGF-alpha was associated with increased malignant properties as TGF-alpha transfectants showed increased tumorigenicity in athymic nude mice. The administration of tetracycline reversed the effects of TGF-alpha expression in these cells both in vivo and in vitro, indicating that the alterations of the biological properties were due to the expression of TGF-alpha. Since these cells are continuously grown in a completely chemically defined medium without serum supplementation, it was possible to assign the mechanism underlying the generation of growth factor independence to the replacement of a requirement for exogenous insulin in parental cells by autocrine TGF-alpha.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Convergent input from brainstem coincidence detectors onto delay-sensitive neurons in the inferior colliculus.

Responses of low-frequency neurons in the inferior colliculus (IC) of anesthetized guinea pigs were studied with binaural beats to assess their mean best interaural phase (BP) to a range of stimulating frequencies. Phase plots (stimulating frequency vs BP) were produced, from which measures of characteristic delay (CD) and characteristic phase (CP) for each neuron were obtained. The CD provides an estimate of the difference in travel time from each ear to coincidence-detector neurons in the brainstem. The CP indicates the mechanism underpinning the coincidence detector responses. A linear phase plot indicates a single, constant delay between the coincidence-detector inputs from the two ears. In more than half (54 of 90) of the neurons, the phase plot was not linear. We hypothesized that neurons with nonlinear phase plots received convergent input from brainstem coincidence detectors with different CDs. Presentation of a second tone with a fixed, unfavorable delay suppressed the response of one input, linearizing the phase plot and revealing other inputs to be relatively simple coincidence detectors. For some neurons with highly complex phase plots, the suppressor tone altered BP values, but did not resolve the nature of the inputs. For neurons with linear phase plots, the suppressor tone either completely abolished their responses or reduced their discharge rate with no change in BP. By selectively suppressing inputs with a second tone, we are able to reveal the nature of underlying binaural inputs to IC neurons, confirming the hypothesis that the complex phase plots of many IC neurons are a result of convergence from simple brainstem coincidence detectors.

Acoustic Stimulation↗
PubMed1998

Embryonic entorhinal transplants partially ameliorate the deficits in spatial memory in adult rats with entorhinal cortex lesions.

Our previous studies have demonstrated that axons from grafts of embryonic entorhinal cortex (EC) can reinnervate the deafferented zones in the hippocampus and form synaptic connections with the host dentate gyrus in adult mice and rats deprived of their own entorhinal inputs. Here, we have examined the ability of the EC grafts to ameliorate deficits in spatial memory. Three months after transplantation, the grafted rats and control animals were subjected to Morris water maze testing followed by histological examination. According to the exact position of grafts in the host brain, the rats with lesion and EC transplants were divided into two groups, one with EC grafts contacting both the hippocampus and overlying neocortex (n=7, EC1) and another with EC grafts confined within the hippocampus (n=6, EC2). While EC2 rats were still as impaired as those with lesion and transplants of non-entorhinal cortex (n=10, NEC) or with lesions only (n=7, LES), the EC1 rats performed better than the LES group. In a spatial memory trial, the EC1 group made more crossings over platform site and showed more focused search behavior than EC2, LES, NEC groups. The data suggest that EC grafts could partially ameliorate the deficit in spatial learning behavior in the EC-lesioned adult rats. The requirement for the graft to contact both the neocortex and the hippocampus suggests that the functional effects may be exerted by the formation of new neocortical-EC graft-hippocampal circuits.

Animals↗
PubMed1998

Expression of TGFalpha autocrine activity in human colon carcinoma CBS cells is autoregulated and independent of exogenous epidermal growth factor.

Autocrine transforming growth factor alpha (TGFalpha) activity and control mechanisms for its expression were examined in a representative clonal isolate (CBS4) of a well-differentiated human colon carcinoma cell line designated CBS. CBS4 cells expressed TGFalpha and its receptor, epidermal growth factor receptor (EGFr). Blockade of EGFr and TGFalpha by neutralizing antibodies inhibited clonal growth and the initiation of DNA synthesis from quiescence in CBS4 cells. Therefore, TGFalpha is an autocrine growth factor for CBS4 cells. Several studies have indicated that activation of the EGFr by exogenous EGF stimulates TGFalpha expression. However, in CBS4 cells EGF did not induce TGFalpha mRNA expression, indicating that EGF does not affect TGFalpha transcription in these cells. Exogenous treatment of exponentially growing cells with either EGF or EGFr blocking antibody enhanced release of TGFalpha protein into the conditioned medium. This indicated that the release of TGFalpha into the conditioned medium by exogenous EGF was at least partially due to the displacement of TGFalpha from the TGFalpha/EGFr complexes. Similarly to exponentially growing cells, the EGFr blocking antibody and EGF also enhanced TGFalpha release into the medium of CBS4 cells after release from quiescence. These results indicated that exogenous EGF had little if any effect on TGFalpha expression in these cells and suggested that TGFalpha expression might be under endogenous TGFalpha control. Blockade of the autocrine TGFalpha loop by TGFalpha neutralizing antibody suppressed TGFalpha mRNA both in exponentially growing and quiescent cells, demonstrating that autocrine TGFalpha is autoregulatory in this system.

Antibodies↗
PubMed1998

Molecular genetic studies in lymphocyte apoptosis and human autoimmunity.

Using a genetic approach, we have studied the molecular basis of human autoimmunity with special emphasis on a disease that is due to defective lymphocyte apoptosis. Recently, we and our collaborators have found that the autoimmune/lymphoproliferative syndrome (ALPS), an inherited disease of children comprising marked lymphoid hyperplasia and autoimmune manifestations, is due to abnormalities in the CD95 gene that cause defective lymphocyte apoptosis. Our recent investigations have shown that the mutations in most families with ALPS cause either global or local changes in the structure of a cytoplasmic portion of the molecule called the 'death domain'. These death domain alterations impair binding of the adapter protein FADD/MORT1 and result in a failure to activate apoptotic caspases after CD95 (Fas/APO-1) cross-linking. Mutations in apoptotic caspases may also contribute to the pathogenesis of ALPS in individuals that have no CD95 gene mutations.

Adaptor Proteins, Signal Transducing↗
PubMed1998

[Evaluation of the growth and contraction of composite skin].

OBJECTIVE: To evaluate the growth and contraction of different composite skin grafts. METHODS: The status of the following composite skin grafts was evaluated over 2 years: allogeneic sucking pig dermis and autologous epidermis (group 1, n = 19), allogeneic young pig dermis and autologous epidermis (group 2, n = 7), autologous epidermis (group 3, n = 8). The effects of gestation on the composite skin grafts were also assessed. RESULTS: It showed that composite skin grafts had smooth surface and no scar formation during 2 to 124 weeks after transplantation. After week 36, the surface area of each group enlarged with different growth rates: group 1 > group 2 > group 3 (P < 0.01). Whole piece grafting was significantly better than joining together of smaller pieces after week 24 (P < 0.001). During pregnancy, CS had good growth ability and elasticity (P < 0.01). Histological study showed that group 1 had rapid growth of skin papillae and epidermal ridges similar to normal skin at week 24. CONCLUSION: As CS graft with trypsin treated allogeneic sucking pig dermis as a substitute for dermis showed the advantages of rapid growth, good elasticity and stability, it is suggested that it could be used in clinical practice.

Animals↗
PubMed1998

[Effects of dibutyl phthalate on the proliferation and apoptosis of leukemic cells].

This study was designed to investigate the effects of dibutyl phthalate (DBP) on the proliferation and apoptosis of leukemic cells. The results showed that DBP suppressed the proliferation of HL-60 and K562 leukemic cells in a dose-dependent and time-dependent manner. Inducing HL-60 and K562 leukemic cells to die via apoptosis were confirmed by that the percentage of the apoptotic cells in morphology and of the DNA fragmentation increased significantly and that typical ladders of apoptosis were shown by gel electrophoresis when HL-60 and K562 cells were exposed to the DBP. Also, K562 leukemic cells was less susceptible to the DBP than HL-60 cells. These results indicate that DBP can inhibit the proliferation of HL-60 and K562 leukemic cells and induced them to die via apoptosis.

Antineoplastic Agents↗
PubMed1998

[Culture of murine HPP-CFC in vitro using conditioned medium substitutefor recombinant growth factors].

OBJECTS: To study the clonal growth on single layer, agar of high proliferative potential colony-forming cells (HPP-CFC) of bone marrow obtained from both normal mice (NBM) and mice treated 2 days earlier with 5-fluorouracil (FU,BM) using conditioned media. MATERIAL AND METHODS: Using liquid cell culture to harvert WEHI2-CM and L929-CM as the substitutes for IL-3 and M-CSF respectively; using semi-solid culture to assay HP-CFCin vitro. RESULTS: (1) the combination of WEHI3-CM and L929-CM produced HPP-CFC in vitro, and the addition of rhIL-1 alpha, rhIL-6 and rmGM-CSF further enhanced HPP-CFC was enriched in the FU2 BM. Morphological investigation showed that the HPP-CFC colony was large and compact, great than 0.5mm in diameter and contained more than 50,000 cells, most of which were macrophage like cells. The hydroxyurea suicide rate for HPP-CFC was less than 10%. CONCLUSION: The results suggested that (1) WEHI3-CM and L929-CM can be used as the substitutes of IL-3 and M-CSF to stimulate the formation of HPP-CFC; (2) FU can enrich HPP-CFC of the mice.

Animals↗
PubMed1998

[Applied anatomy of the vascularity in the ileocolic region and its clinical significance].

To understand the characteristics of the patterns of arteries and veins distributed over the ileocolic segment, 50 cadavers were studied by gross-anatomy. The arteries, veins and their paracolic anastomoses distributed over ileocecal region, ascending colon and transverse colon were observed. The results showed that the distribution pattern of venous vessel was far more constant than that of artery, that the arrangements of artery in the ileocolic segment were classified into 7 types, and there were no interruption of paracolic anastomoses between arteries. But in 3 specimens the paracolic anastemoses between the right colic vein and the middle colic vein were completely interrupted. These findings may be useful in guiding clinical practice and preventing postoperative complications in ileocolic replacement of esophagus.

Adult↗
PubMed1998

[Effects of retionoic acid and GM-CSF on apoptosis of HL-60 cell induced by mild heat].

The effects of several factors on the apoptosis of HL-60 cells, a human acute myeloid leukemia cell line, were investigated. The apoptosis model was established with mild heat. Typical changes of cell morphology and characteristic DNA ladder pattern were found. The effect of apoptosis induced by mild heat was enhanced, when HL-60 cells were pretreated with the retinoic acid. By contraries, that of apoptosis was displayed with the slight inhibition while HL-60 cells were pretreated with rhGM-CSF. We also observed the alterations of mRNA expressions of c-myc by the dot hybridization. The results indicate that both the mild heat and the combination of mild heat and retinoic acid obviously reduce the mRNA expression of c-myc compared to the control group.

Apoptosis↗
PubMed1998

[Experimental study on immune privilege in subretinal space].

OBJECTIVE: To evaluate the immune characteristics of subretinal space. METHODS: Retina of DBA/2 mouse with or without Complete Freund's Adjunvate (CFA), or human peripheral blood mononuclear cell (PBMC), or syngenic retina, and DMEM as negative control were transplanted into subretinal spaces of BALB/C mouse. Delayed-type hypersensitivity (DTH) and specific killing of cytotoxic T lymphocyte (CTL) were detected two weeks later and histopathological examination was carried out as well. RESULTS: There were no significant differences in DTH between four experimental groups and control group, but the specific killing of CTL was significantly higher than that of the control group. Retinal transplant was survival. Immune rejection occurred in human PBMC group. CONCLUSION: Limited immune privilege occurs in a certain degree after subretinal space transplantation.

Animals↗