Biomedical subjects

L Chen

Publications and source records attributed to L Chen.

At least 1,027 records · Page 57Linked to original sources

PubMed1996

Immunoresponses of humanized SCID mice to human lung cancer cells.

HuPBL-SCID mice were used to explore how they would response to human tumor cells of 801/MLC. Living 801/MLC cells appeared to be fetal to the the mice due to the production of human TNF. The huPBL-SCID mice did not generate any noticeable amount of specific human immunoglobulin either by single immunization with living 801/MLC cells or by repeated immunization with irradiated 801/MLC cells. Our preliminary experiments with huPBL-SCID mice showed that such chimeras would be a very useful models for tumor immunological researches.

Animals↗

PubMed1996

[Study on local huangjiabang delivery device].

This article reports the pharmacological functions of local Huangjiabang delivery device which mainly includes medicinal herbs. The experimental study showed that Huangjiabang could inhibit the predominant cultivable organisms in periodontal disease significantly, and could also inhibit inflammatory swelling caused by xylene. Jiaochacaijiao, egg serum and filter-paper-granuloma significantly. The preliminary clinical observation showed that GI, PLI, SBI and PD were reduced remarkably in Huangjiabang administered pockets after two days and seven days of treatment. It is suggested that this new direct drug delivery system with medicinal herbs has wide prospect in the treatment of periodontal disease.

Administration, Topical↗

PubMed1996

[Effects of human interferon-alpha on periphral blood mononuclear cells of the patients with autoimmune thyroid disease].

Interferon-alpha (IFN-alpha) therapy for hepatitis and malignant tumor frequently results in autoimmune thyroid disease (AITD); this fact indicates an association of IFN-alpha with autoimmunity. In order to study the mechanism, an investigation of the effects of human IFN-alpha on T cells, T cell subpopulations, B cells, macrophages and natural killer cells of patients with AITD and normal controls was carried out. It has been found that T cells were inhibited by IFN-alpha with dosage dependency, particularly the T suppressor (CD8/CD11b) in both the patients with AITD and normal controls. An increase in number of B cells and macrophages with stimulation of IFN-alpha was also found in both groups. The results suggest that the decrease of suppressive T cells and increase B cells and macrophages may be responsible for IFN-alpha induced autoimmunity.

Adult↗

PubMed1996

[Synthesis and distribution of endothelin in rats with pulmonary hypertension induced by chronic hypoxia].

OBJECTIVE: To study the synthesis and distribution of endothelin (ET) in the rat model of pulmonary hypertension (PH). METHOD: By chronic hypobaric hypoxia (10%-10.5% O2, 4-18 d), a stable rat model of PH was established. The plasma ET level in the rat was measured by radioimmunoassay and the ET-like immunoreactivity in the rat's lung tissue was observed morphologically by immunohistochemical staining. RESULTS: The concentrations of plasma ET were significantly higher in the hypoxic rat model than in control animals (P < 0.01), but there were no significant differences in different time groups of the hypoxic rats (P > 0.05). ET's synthesis was mostly localized within pulmonary vascular vessels sharply contrasted with normal rats in which there were little or no ET staining. CONCLUSION: The results suggested that hypoxia might be the main reason for promoting ET's synthesis and release.

Animals↗

PubMed1996

[Immunohistochemical studies of nonsecreting pancreatic islet cell tumors secreting many hormones].

To observe the distribution of multiple hormones in nonsecreting islet cell tumors of the pancreas and to study their histogenesis, 9 pancreas nonsecreting islet cell tumor cases were studies using 12 kinds of antisera. The results showed that 4 cases were positive for insulin, 6 for glucagon, 1 for gastrin, 6 for somatostatin, 1 for gastrin 5 for calcitonin, 7 for neurotensin, 4 for ACTH, 3 for TSH, 5 for FSH and 2 for LH. It is therefore confirmed that these tumors synthesize and secrete peptide hormones and glycoprotein hormones. We believe that these endocrine cells originate from primitive multipotential stem cells.

Adenoma, Islet Cell↗

PubMed1996

[Anti-tumor effects of heiji (radix Astilbes chinensis].

The experimental results indicate that the herb Heiji is able to suppress the growth of transplantable tumor (S180) in mice by 30%-51% (P < 0.01), prolong the vital stage of the EAC transplanted mice by 44% (P < 0.01) and raise the lymphocyte transformation rate in lower concentrations in vivo. It follows that Heiji has positive anti-tumor effects and deserves further research as a new anti-tumor herb.

Animals↗

PubMed1996

[Clinical analysis of diffuse axonal injury].

Sixty cases of diffuse axonal injury were analysed in this paper. All cases were caused by traffic accident; the mortality was 53.12%. Clinical manifestations were post-traumatic immediate and continuous coma with severe dysfunction of brain stem. MRI is helpful for clinical diagnosis. Pathological findings include the diffuse axonal injury of cortical while matter, corpus callosum, brain stem, and focal hemorrhage and infarction. The early use of hyperbaric oxygen combined with neuro-growth factor as an effective therapy is recommended.

Accidents, Traffic↗

PubMed1996

[On diagnostics of malignant meningioma and invasive meningioma].

We have made a clinicopathological study of 90 cases of malignant meningiomas and 18 cases of invasive meningiomas. The results show that the diagnostic features of malignant meningioma include increased cellularity, nuclear pleomorphism, tumorous giant cells, numerous mitotic figures, focal necrosis, cystic change and hemorrhage. The diagnosis of malignant meningioma can be more positively made when invasive growth, recurrence and metastasis are present. In making the diagnosis of invasive meningioma, both changes of benign meningioma and invasive growth should be present.

Adolescent↗

PubMed1996

[The relationship of non-Hodgkin's lymphoma with P16 protein expression].

The expression of P16 protein was examined in 45 cases of non-Hodgkin's lymphoma (NHL), 4 cases of reactive hyperplasia of lymph node (RHLN) and 6 cases of normal spleen with immunohistochemical staining. Positive reaction of P16 protein was observed in some lymphocytes of RHLN and splenic nodule and around splenic sinus. The positive rate of P16 protein expression in NHL was 37.8% (17/45). The positive rates of P16 protein expression for the low intermadiate- and high-grade malignancy groups were 66.7% (10/15), 37.5% (6/16) and 7.1% (1/14) respectively. There was a significant difference between the low malignancy NHL and the high malignancy NHL (P < 0.005) in expression rate of P16 protein. It suggests that P16 protein expression may be one of the important parameters in estimating the prognosis of patients with NHL.

Adolescent↗

PubMed1996

[Effect of microinjection of neurotensin into hypothalamic paraventricular nucleus on gastric acid secretion in rats].

Effects of microinjection of neurotensin (NT) into the hypothalamic paraventricular nucleus (PVN) on gastric acid secretion were investigated in urethane-anesthetized rats. The results were as follows: NT microinjection into PVN produced a dose-dependent decrease in gastric acid output (GAO); this inhibitory effect of NT was completely blocked by icv pretreatment with the alpha-adrenergic receptor antagonist phentolamine or after bilateral cervical vagotomy, suggesting that the effect may be related with activation of alpha-adrenergic receptors in the nucleus and mediated by vagal nerves.

Adrenergic alpha-Antagonists↗

PubMed1996

[Radical operation for Budd-Chiari syndrome under extracorporal circulation with deep hypothermia and circulatory pause].

The authors designed a new operation for the treatment of Budd-Chiari syndrome under deep hypothermia anesthesia with extracorporeal circulation, opening the superhepatic inferior vena cava (IVC) when the circulation was paused. Then the diseased focuses of IVC and HVs were resected under direct bloodless vision. After the incision of IVC was sutured, the normal circulation restored. From September 1993 to November 1995, 11 cases were treated in our hospital. All patients are well postoperatively, and followed up from 5 to 33 months. Ultrasonography revealed patent IVC and hepatic veins in all cases.

Adult↗

PubMed1996

[The effect of tinidazole in the treatment of adult periodontitis].

Fifty-two adult periodontitis patients were treated by the tablets of tinidazole (TNZ), and 23 patients treated by metronidazole (MNZ) served as control group. The effective rate of TNZ in adult periodontitis patients was 73.1%, which was significantly higher than that of the control group (43.5%). Antimicrobial studies showed that the capability of TNZ to kill the periodontal dominant anaerobic bacteria, especially B. gingivalis and B. melaninogenicus, was better than that of MNZ. The minimal inhibitory concentration (MIC) of TNZ to Bacteroides, Fusobacterium, Veillonella, Eubacterium, Antinomyces, Peotostreptococus and Anaerobic Streptococus was lower than that of MNZ and actylspiramycine.

Adult↗

PubMed1996

[Plasma endothelin-1 and pulmonary hemodynamics at pre-or post exercise in chronic obstructive pulmonary disease].

OBJECTIVE: To investigate whether plasma endothelin-1 (ET-1) affects the pathologic physiologic process of pulmonary hypertension (PH) secondary to chronic obstructive pulmonary disease (COPD). METHODS: Forty-six patients with COPD who underwent right float-assisted cardiac cather examination and a supine ergometer exercise test were classified into 3 groups, that is, group A with PH, group B with latent PH and group C without PH. RESULTS: (1) There was a marked higher ET-1 level in femoral arterial plasma than in pulmonary arterial plasma from group A at pre-or post-exercise or group B at post-exercise. (2) Plasma ET-1 levels of A and B groups post-exercise are higher that that in group B post-exercise than that in group C. (3) ET-1 level is also higher in group B post-exercise than that in group C. (4) There was significant correlation between the ET-1 level and mPAP, PVR, PaO2 of group A at pre- and post-exercise or group B at post-exercise. CONCLUSION: These finding suggest a role for ET-1 in regulating pulmonary circulation of PH secondary to COPD).

Aged↗

PubMed1996

Calcium channel blockade and anti-free-radical actions of panaxatriol saponins in cultured myocardiocytes.

AIM: To identify the calcium channel blockade and anti-free-radical actions of panaxatriol saponins Re, Rf, Rg1, Rg2, Rh1, and oleanolic acid saponin Ro. METHODS: On ventricular myocytes of Wistar rats, single channel activities of B, L, and T type calcium channels were recorded with the cell-attached configuration of patch-clamp technic, and free radical contents were measured with electron spin resenance method. RESULTS: Re, Rg1, Rg2, and Rh1 shortened the open times, prolonged the close times, and reduced the open-state probabilities of B, L, and T type calcium channels; Rf shortened the open time, prolonged the close time and reduced the open-state probability of L type calcium channel; Ro did not influence the activity of calcium channels (60 mumol.L-1). Re, Rg1, Rg2, and Rh1 antagonized the increase of free radical content induced by xanthine 0.42 mmol.L-1-xanthine oxidase 5.3 nmol.L-1; Ro and Rf had no effect (30 mumol.L-1). CONCLUSION: Re, Rg1, Rg2, and Rh1 had both the calcium channel blockade and antifree-radical actions. Rf had blockade action on L type calcium channel.

Animals↗

PubMed1995

Impaired motor coordination correlates with persistent multiple climbing fiber innervation in PKC gamma mutant mice.

It is generally believed that a smooth execution of a compound movement, or motor coordination, requires learning of component movements as well as experience-based refinement of the motor program as a whole. PKC gamma mutant mice display impaired motor coordination but intact eyeblink conditioning, a form of component movement learning. Cerebellar long-term depression, a putative cellular mechanism for component motor learning, is also unimpaired. Thus, PKC gamma mutant mice are defective in refinement of the motor program. In the accompanying paper, we demonstrate that innervation of multiple climbing fibers onto Purkinje cells persists in adulthood in these mutant mice. We propose that this defective elimination of surplus climbing fibers underlies motor discoordination.

Animals↗

PubMed1995

Regulation of vascular smooth muscle growth by alpha 1-adrenoreceptor subtypes in vitro and in situ.

Rat aorta smooth muscle cells which express all three alpha 1-adrenoreceptors (alpha 1A, alpha 1B and alpha 1D) were used to determine the effect of stimulation of alpha 1-adrenergic receptor subtypes on cell growth. "Combined" alpha 1-adrenoreceptor subtype stimulation with norepinephrine alone caused a concentration-dependent, prazosin-sensitive increase in protein content and synthesis: 48 h of stimulation at 1 microM increased cell protein to 216 +/- 40% of time-matched controls (p = 0.008) and RNA to 140 +/- 13% (p = 0.03); protein synthesis increased to 167 +/- 13% (p < 0.01) after 24 h. Stimulation with norepinephrine plus the selective alpha 1A/alpha 1D antagonist 5-methylurapidil produced greater increases in alpha-actin mRNA (270 +/- 40% at 8 h; p = 0.007), total cell protein (220 +/- 45% at 24 h; p = 0.004), and RNA (135 +/- 8% at 24 h; p = 0.01). These effects were prevented by pretreatment with the selective alpha 1B antagonist chloroethylclonidine. Comparable results were obtained for intact aortae. Stimulation with norepinephrine plus 5-methylurapidil increased (p < 0.05) tissue protein, RNA, dry weight, and alpha-actin mRNA; and as in culture cells, combined stimulation with norepinephrine alone attenuated these responses. By comparison, adventitia (fibroblasts) was unaffected. Removal of endothelial cells had no effect. alpha 1B mRNA decreased by 42 +/- 12% (p = 0.01) in cultured cells during combined alpha 1-adrenoreceptor stimulation and by 23 +/- 8% (p = 0.03) for intact aorta. alpha 1D and beta-actin mRNA were unchanged in cultured cells, aorta media, and adventitia. These findings suggest that prolonged stimulation of chloroethylclonidine-sensitive, possibly alpha 1B-adrenoceptors induces hypertrophy of arterial smooth muscle cells and that stimulation of 5-methylurapidil-sensitive, non-alpha 1B-adrenoreceptors attenuates this growth response.

Actins↗

PubMed1995

Expression of brain-type creatine kinase and ubiquitous mitochondrial creatine kinase in the fetal rat brain: evidence for a nuclear energy shuttle.

To test the hypothesis that embryonic brain cells utilize a creatine phosphate energy shuttle, we examined the pattern of creatine kinase (CK) isoform expression and localization in the fetal rat brain. Moderate levels of CK activity are present at embryonic day 14 (7 U/mg protein) and decrease slightly until 3 days postpartum followed by a rapid, fourfold up-regulation to adult levels by 1 month (18 U/mg protein). In parallel with changes in enzyme activity, there is a biphasic and coordinate pattern of expression of brain-type CK (BCK) and ubiquitous mitochondrial CK (uMtCK) determined by nondenaturing electrophoresis and immunoblot analysis. The localization of CK isoforms was examined by immunocytochemistry, and, during the fetal period, BCK and uMtCK immunoreactivity was detected throughout the central and peripheral nervous system, especially in neuroepithelial regions of the cerebral vesicles and spinal cord. In large cells within the olfactory neuroepithelium and ventral spinal cord, differential compartmentation of CK isoforms was evident, with BCK localized primarily in cell nuclei, whereas uMtCK immunoreactivity was present in the cell body (but not within nuclei). In olfactory bulb neuroepithelium, both isoforms were expressed in the middle zone of the germinal layer associated with DNA synthesis. In embryonic skeletal and cardiac muscle, which also express BCK, the same compartmentation of BCK was seen, with BCK localized primarily in the cell nucleus of cardiac and skeletal myoblasts. These results demonstrate a coordinate pattern of expression and compartmentation of BCK and uMtCK isoforms in the fetal brain that, in some cells, provides the anatomic basis for a nuclear energy shuttle.

Animals↗

PubMed1995

Protective immunity induced by B7/CD28-costimulated gamma delta T cells to the EL-4 lymphoma in allogenic athymic mice.

We previously reported that the murine EL-4 lymphoma (H-2b) transduced with a retrovirus containing the murine B7-1 gene (B7+ EL-4) grew transiently for several weeks and subsequently regressed in allogenic BALB/c (nu/nu) athymic mice (H-2d). We now show that, in contrast, B7+ EL-4 cells grow progressively in several combined immunodeficiency mice, including SCID and NIH III mice, which lack T cells expressing either TCR-alpha beta or -gamma delta. Furthermore, depletion of gamma delta T cells with a specific mAb made possible the progressive growth of B7+ EL-4 cells in 90% of athymic mice while depletion of alpha beta T cells allowed tumor growth in 50% of these mice. Immunization of athymic mice with B7+ EL-4 cells prevented the outgrowth of wild-type B7- EL-4 cells. This protective immunity was abrogated by in vivo treatment with an anti-TCR-gamma delta mAb, further indicating that gamma delta T cells play an important role in tumor rejection by athymic mice. A gamma delta T cell line, Tc1, was established from B7+ EL-4-immunized athymic mice by repeated restimulation in vitro with irradiated B7+ EL-4 cells. When tested against a broad spectrum of target cells, Tc1 lysed several murine lymphoma lines, but did not lyse other tumor lines, suggesting that the Ag recognized by Tc1 has a limited distribution. Our data demonstrate that gamma delta T cells, and, to a less extent, extrathymic alpha beta T cells, mediate an immune response against B7+ EL-4 cells in allogeneic athymic mice.

Animals↗