Search PubMed⌕ Search

Biomedical subjects

R Huang

Publications and source records attributed to R Huang.

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

[Effects of defibrinogenase on photochemically induced middle cerebral artery occlusion in stroke-prone renovascular hypertensive rats].

OBJECTIVE: To investigate the effects of intravenous injection of defibrinogenase on dissoliving dissolve thrombus and salvaging cerebral infarction in stroke-prone renovascular hypertension rats (RHRSP) with middle cerebral artery occlusion(MCAO). METHODS: The MCAO in RHRSP was induced by administration in photosensitive dye, rose bengal, and irradiation of the main MCA with a focus laser beam. The thrombus in MCA and cerebral infarction were examined microscopically in HE stained sections. Infarction size was determined in triphenyltetrazolium chloride stained sections. Defibrinogenase was injected intravenously at 3, 6, 9, 12 hours and 3, 7 days after MCAO, meanwhile the control group received normal saline. All rats were killed at 72 hours and evaluated by pathological methods after treatment. RESULTS: In the treatment group, the thrombi were dissolved totally at 3 hours after MCAO, 75% at 6 hours, 13% at 9 hours. Defibrinogenase failed to dissolve thrombus beyond 12 hours after MCAO, just as control group. In comparison with the control group, defibrinogenase significantly reduced infarction size. There was no evidence of hemorrhage. CONCLUSIONS: Defibrinogenase can reduce infarction size and dissolve thrombus in 6 hours after MCAO without the side effect of hemorrhage.

Ancrod↗
PubMed1999

[Microelectrode-guided posteroventral medial pallidotomy for Parkinson's disease].

OBJECTIVE: To introduce the methods and effects of microelectrode-guided posteroventral pallidotomy (PVP) for Parkinson's disease. METHODS: 109 patients underwent PVP by microelectrode electrophysiological recording for intraoperative target localization. 45 patients underwent unilateral PVP, 21 patients simultaneous bilateral PVP, 43 patients combined thalamotomy and PVP. Modified Webster Scale was used for objective assessments before and after operation. Postoperative CT scan or MRI was performed to localise lesions. RESULTS: Microelectrode recording usually led to a final pallidotomy lesion position that deviated from the CT stereotactically defined target point. The change rate of targets was 84.7%. PVP significantly and immediately improved all Parkinsonian motor signs and reduced drug-induced motor fluctuations and dyskinesia. The mean Webster Scale was improved by (72.7 +/- 11.3)% in the "on"" state, and (89.3 +/- 8.1)% in the "off" state. No patient showed permanent complications. CONCLUSIONS: Microelectrode-guided PVP was proved to be safe and effective. Bilateral PVP and combined PVP can significantly and immediately abolish all Parkinsonian motor signs. Physiological methods of microelectrode recording can significantly improve the safety and efficacy of PVP, and decrease the rate of complication.

Adult↗
PubMed1998

Products of sphingolipid catabolism block activation of the p21-activated protein kinases in neutrophils.

Neutrophils stimulated with the chemoattractant FMLP are known to exhibit a rapid and transient activation of two p21-activated protein kinases (Paks) with molecular masses of approximately 63 and 69 kDa. Paks can be detected by their ability to undergo renaturation and catalyze the phosphorylation of a peptide substrate that corresponds to amino acid residues 297 to 331 of the 47-kDa subunit of the nicotinamide-adenine dinucleotide phosphate-oxidase complex (p47-phox) fixed within a gel. In this study, we demonstrate that N-acetylsphingosine (C2-ceramide) and a variety of sphingoid bases (e.g., D-erythrosphingosine) block activation of the 63- and 69-kDa Paks in neutrophils. The concentrations of these lipids that were effective in blocking Pak activation were similar to those that inhibit a variety of neutrophil responses. Activation of the 63- and 69-kDa Paks was also markedly reduced in neutrophils treated with sphingomyelinase before stimulation. Moreover, we report that addition of C2-ceramide or D-erythrosphingosine to neutrophils after stimulation with FMLP markedly enhances the rate of Pak inactivation. These effects were not mimicked by arachidonate, which is a potent disorganizing agent of neutrophil membranes. These data support and extend the proposal that sphingoid bases may establish a set point in neutrophils for positive stimuli.

Cells, Cultured↗
PubMed1998

IL-10 production in common variable immunodeficiency.

Common variable immunodeficiency, (CVI) is a heterogeneous primary immunodeficiency disease in which there are T and B cell defects. Since IL-10 in conjunction with anti-CD40 promotes secretion of IgG, IgA, and IgM by CVI B cells, these studies were performed to investigate IL-10 production in CVI. Mitogen or anti-CD3 stimulated CVI peripheral blood mononuclear cells, or isolated T cells produced an insignificant amount of IL-10 over background levels. CVI monocyte IL-10 production was substantial and greater than that of normal controls. Anti-IL-10-neutralizing antibody strongly enhanced CVI T cell proliferative responses to PHA, but only to an insignificant extent, soluble antigens. IL-2 plus anti-IL-10 enhanced CVI proliferative responses to antigens significantly more over baseline than for cells of similarly tested normal controls. These data suggest that CVI T cell secretion of IL-10 is deficient, but that monocyte-derived IL-10, plus a relative lack of IL-2 production, could contribute to the defects of cell proliferation in this disorder.

Adolescent↗
PubMed1998

Segmentation of the vertebrate body.

The segmental character of the vertebrate body wall is reflected by metamerically arranged tissues that are patterned during embryonic life as a consequence of somite formation, compartmentalization and differentiation. The somites bud off the paraxial mesoderm in a cranio-caudal sequence and are compartmentalized by local signals from adjacent structures. These signals may be mediated by diffusible substances such as Sonic hedgehog (Shh), Wnts and Bone morphogenetic protein (BMPs) or by cell-cell interactions via membrane-bound receptors and ligands such as Delta and Notch. Compartmentalization of the somites and their derivatives is reflected by the differential expression of developmental regulatory genes such as Pax-1, 3, 7 and 9, MyoD, paraxis, twist and others. Secondary segmentation is imposed upon other tissues, such as blood vessels and nerves, by the rearrangement and regionalization of the somitic derivatives, especially the sclerotome. Early cranio-caudal identity is determined by the expression of different Hox genes. Finally, fusion of segmental anlagen occurs to form segment-overbridging skeletal elements and muscles. The expression of homologous genes indicates that the process of segmentation in vertebrates and invertebrates is homologous, derived by descent from a common ancestor.

Animals↗
PubMed1998

Morphological and molecular changes of maize plants after seeds been flown on recoverable satellite.

Dry seeds of Zea mays, heterozygous for Lw1/lw1 alleles, sandwiched between nuclear track detectors aboard Chinese satellite for 15 days, were recovered and mutations in morphological characters on plants developed from these seeds, as well as their selected progenies, were investigated. The dosimetric results indicated that 85% of the seeds received at least 1 hit with Z > or = 20. About 10% of plants developed from flown seeds and 40% of observed selfed lines from the first generation plants showed some morphological changes, such as yellow stripes displayed on leaves, dwarf, anomogensis of floral organs and yellow-green seedlings, when compared with those from ground control. Using yellow stripes on leaves as the main endpoint for evaluating mutation induced in space environment, the frequency of stripe occurrence was 4.6% in the first generation plants, comparable with the results obtained from Long Duration Exposure Facility (LDEF) mission (Mei et al., 1994), but much lower than those from ground based 60 Co-gamma treatment at a dose of 100 Gy, which reached 35.5% in the selfed lines of the second generation. One hundred and ten random primers were screened in RAPD analysis to detect the variation on genomic DNA of plants with stripes on leaves. Of these primers, 10.9% were able to generate polymorphic bands between mutated plants and control, also, common band patterns in several progenies with the same mutation phenotype were observed. These results demonstrated that space radiation environment could induce inheritable mutagenic effects on plant seeds, and verified the change in genetic material in the mutants. Further study will be needed for a better understand of the nature and mechanism of this induction of mutation.

Cobalt Radioisotopes↗
PubMed1998

The trophic effects of purines and purinergic signaling in pathologic reactions of astrocytes.

This article reviews the effects of extracellular purine bases, nucleosides, and nucleotides as intracellular signaling molecules with trophic effects on cells after insults to the brain and spinal cord. Astrocytes are the principal source of extracellular purines in brain after injury, ischemia, or trauma. In vitro and in vivo extracellular purines have both immediate and long-term trophic effects, including stimulation of astrocyte and neuronal differentiation, mitosis, morphogenesis, apoptosis, and stimulation of growth and trophic factor synthesis. The effects of the nucleoside adenosine and the nucleotide adenosine triphosphate (ATP) are mediated principally via specific receptors on the cell surface coupled to a series of signaling cascades. Unlike adenosine and ATP, guanosine and guanosine triphosphate (GTP) do not act at classical purine receptors. However, they exert similar effects on astrocytes, apparently by causing the astrocytes to release large amounts of adenosine and ATP over prolonged periods. The release of adenosine and ATP may be related to the effects of guanosine on the purine nucleoside transporters in the cell membrane, whereas the release of ATP may be due to the effects of GTP on the ATP-binding cassette (ABC) proteins. Physiologically, the effects of guanosine are important because this nucleoside, unlike adenosine, remains elevated for prolonged periods after brain injury.

Adenosine↗
PubMed1998

Neutrophils stimulated with a variety of chemoattractants exhibit rapid activation of p21-activated kinases (Paks): separate signals are required for activation and inactivation of paks.

Activation of the p21-activated protein kinases (Paks) was compared in neutrophils stimulated with a wide variety of agonists that bind to receptors coupled to heterotrimeric G proteins. Neutrophils stimulated with sulfatide, a ligand for the L-selectin receptor, or the chemoattractant fMet-Leu-Phe (fMLP), platelet-activating factor, leukotriene B4, interleukin-8, or the chemokine RANTES exhibited a rapid and transient activation of the 63- and 69-kDa Paks. These kinases exhibited maximal activation with each of these agonists within 15 s followed by significant inactivation at 3 min. In contrast, neutrophils treated with the chemoattractant and anaphylatoxin C5a exhibited a prolonged activation (>15 min) of these Paks even though the receptor for this ligand may activate the same overall population of complex G proteins as the fMLP receptor. Addition of fMLP to neutrophils already stimulated with C5a resulted in the inactivation of the 63- and 69-kDa Paks. Optimal activation of Paks could be observed at concentrations of these agonists that elicited only shape changes and chemotaxis in neutrophils. While all of the agonists listed above triggered quantitatively similar activation of the 63- and 69-kDa Paks, fMLP was far superior to the other stimuli in triggering activation of the c-Jun N-terminal kinase (JNK) and the p38 mitogen-activated protein kinase (MAPK). These data indicate that separate signals are required for activation and inactivation of Paks and that, in contrast to other cell types, activated Pak does not trigger activation of JNK or p38-MAPK in neutrophils. These results are consistent with the recent hypothesis that G-protein-coupled receptors may initiate signals independent of those transmitted by the alpha and betagamma subunits of complex G proteins.

Animals↗
PubMed1998

Two-kidney, two clip renovascular hypertensive rats can be used as stroke-prone rats.

BACKGROUND AND PURPOSE: The cerebrovascular lesions in stroke-prone spontaneously hypertensive rats are not only dependent on high blood pressure but partly related to pressure-independent genetic factors. The aim of the present study was to observe whether spontaneous stroke occurred in renovascular hypertensive rats without a genetic deficiency. METHODS: The 1-kidney, 1 clip (1k1c); 2-kidney, 1 clip (2k1c); and 2-kidney, 2 clip (2k2c) methods were used to induce hypertension in male Sprague-Dawley rats with a ring-shaped silver clip. Sham-operated rats were used as controls. Blood pressure and neurological symptoms were observed in the rats without any artificial inducement. Brain sections stained with hematoxylin-eosin and phosphotungstic acid-hematoxylin were examined under a microscope to determine stroke foci. RESULTS: The attack rate of stable hypertension was 100% (55/55) in the 2k2c group, which was significantly higher than that in the 1k1c (23/30, 76.7%) and 2k1c (21/30, 70%) groups (P<0.01). None of the rats in the 2k2c group died of acute renal failure or suffered from diffuse cerebral lesions postoperatively. Forty weeks after renal artery constriction, the incidence of spontaneous stroke in the 2k2c group was 61.8% (34/55), which was significant higher than that in the 1k1c (7/30, 23.3%) and 2k1c (5/30,16.7%) groups (P<0.01). Stroke foci were not observed in normotensive controls. CONCLUSIONS: We conclude that 2k2c renovascular hypertensive rats with proper renal artery constriction can be used as stroke-prone renovascular hypertensive rats independent of a genetic deficiency.

Animals↗
PubMed1998

Stroke-prone renovascular hypertensive rats.

PURPOSE: To summarized the methods for establishment, characteristics of vascular lesions in brain and heart and the application of stroke-prone renovascular hypertensive rats (RHRSP). DATA SOURCES AND METHODS: Most published original articles about RHRSP in our laboratory were reviewed. RESULTS: After the renal arteries were constricted bilaterally with ring-shape silver clips, the stroke-prone renovascular hypertensive rats were established. Hypertension was produced in all RHRSP (100%). The peak of blood pressure in RHRSP reached 29.1 +/- 3.0 kPa. The lesions of cerebral arteries and arterioles and the damage of cerebral capillary structure by hypertension were observed in the RHRSP. The incidence of spontaneous stroke was 56.4% within 40 weeks after the renal artery constriction. Left ventricular hypertrophy and small coronary arterial lesions in myocardium were discovered in all RHRSP. Myocardial infarction occurred spontaneously in 41.8% of RHRSP. The animal models have been used for the studies on mechanisms of stroke and myocardial infarction. CONCLUSIONS: Because the vascular lesions in cerebrum and heart in RHRSP are similar to that in human beings with hypertension, RHRSP can be used in the studies on mechanisms of hypertensive arteriosclerotic stroke and cardiac lesions and on verifying the effects of different medications to complications of hypertension, and the results might be more reliable than that in animal models without hypertension.

Animals↗
PubMed1998

[Secondary infection of the ovarian endometriotic cysts].

OBJECTIVE: To explore the clinic manifestations, diagnostic methods and principles of management in the secondary infection of the endometriotic cysts of ovary. METHODS: Thirteen cases of the infected ovarian endometriotic cysts were analysed retrospectively in our hospital from Jan. 1990 to Dec. 1996. The diagnosis was confirmed by the operation and pathologic findings. RESULTS: The clinic manifestations were divided into five types, namely acute, subacute, chronic, occult and stabile types. The definitive diagnosis can be made by abdominal pain, fever and adnexal mass combined with B-scan findings and chocolate-brown purulent fluid which was punctured from the adnexal mass. Operation was the main method for treatment. CONCLUSIONS: Secondary infection of the endometriotic cyst is one of the gynecologic emergency. Correct diagnosis and prompt management are of vital importance.

Adult↗
PubMed1998

[Effects in tetramethylpyrazine on TXA2 and PGI2 by cardio-pulmonary bypass in congenital heart diseases with pulmonary hypertension patients].

OBJECTIVE: To study protective effects of tetramethylpyrazine (TMP) on the imbalance of TXA2/PGI2 during cardiopulmomary bypass (CPB) in congenital heart disease (CHD) with pulmonary hypertension (PH) patients. METHODS: Thirty patients suffered from non-cyanotic CHD-PH were randomly divided into control group (n = 15) and treatment group (n = 15). 3 mg/kg of TMP was dripped intravenously after anesthesia and 1 mg/kg of TMP was infused into oxygenator after CPB individually. Blood samples were collected and TXA2 as well as PGI2 were measured after anesthesia induction, 15 min during CPB, 5 min after release of the aortic cross-clamp, and 20 min, 6 hrs and 24 hrs after CPB. RESULTS: There was significant difference between treatment group and control group except before operation and 24 hrs after CPB. CONCLUSIONS: The imbalance of TXA2 and PGI2 in patients with CHD-PH during CPB could correct by TMP.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

[Clinical observation of conservative surgery for adenomyosis].

OBJECTIVE: To study the clinical value of conservative surgery for adenomyosis in reducing symptoms and raising pregnancy rate. METHODS: 26 women with histologically proven adenomyosis who wanted to preserve their reproductive capacity had conservative surgery (adenomyomectomy or remove part lesion). The patient's average age was 35.8 years. The main complaints were dysmenorrhea and hypermenorrhea. Of the 22 married patients, 7 had primary infertility (31.8%), 10 had secondary infertility (45.5%) and 3 had habitual abortion (13.6%). RESULTS: 10 patients had adenomyoma, the lesion were completely removed. Sixteen patients had adenomyosis, the part of lesion were removed. The rate of the severe dysmenorrhea and hypermenorrhea after operation were significantly lower than that before (P < 0.001). After operation, 7 patients with adenomyoma wanted to have a baby, 5 patients conceived, of the total 9 pregnancies, 5 ended in term pregnancy; 14 patients with diffuse adenomyosis wanted to have a baby, 3 patients had 3 pregnancies. One of which ended in term pregnancy. The rate of pregnancy and term delivery in adenomyoma patients were significantly higher than that of adenomyosis patients (P = 0.03, P = 0.002). Among 26 patients, 3 relapsed. The average relapse time was 49.6 months. CONCLUSIONS: The conservative surgery for adenomyoma can reduce symptom and raise pregnancy rate significantly, it can be accepted by young women who want to preserve their reproductive capacity. Though the pregnancy rate of conservative surgery for diffused adenomyosis was low, it still has therapeutic value.

Adult↗
PubMed1998

[Triterpenes and steroidal compounds from Momordica dioica].

Three triterpenes and two steroidal compounds were isolated from the dry root of Momordica dioica. Their structures were elucidated by spectral analyses (MS, IR, 1HNMR, 13CNMR and DEPT) and chemical methods. These compounds are alpha-spinasterol octadecanonate(I), alpha-spinasterol-3-O-beta-D-glucopyranoside(II), 3-O-beta-D-glucuronopyranosyl gypsogenin(III), 3-O-beta-D-glucopyranosyl gypsogenin(IV) and 3-O-beta-D-glucopyranosyl hederagenin(V). Constituent III is a new compound. The CHCl3 extract of Momordica dioica roots and five isolated constituents showed anticancer activity in pharmacologic testing on cancer cell(L1210). The growth inhibitory index(%) of compound II was shown to be 50%, at the dose of 4 micrograms.ml-1.

Animals↗
PubMed1998

[Study on the determination of tung oil adulterated in vegetable oils by first derivative spectrophotometry].

A method of first derivative spectrophotometry for qualitative and quantitative analysis of tung oil adulterated in vegetable oils, including peanut oil, bean oil, rape seed oil, tea seed oil, palm oil and mixed vegetable oil, was established. The spectrum of tung oil features three valleys at 291.3, 278.3 and 266.4nm, and three peaks at 284.1, 271.5 and 260.7nm. At 291.3nm, the coefficient (deltaE(1%)1cm/deltalambda) was -1.03 x 10(3). When the concentration of tung oil adulterated in vegetable oils was downed to 0.1%, the above specialities still remain and the changes in wavelengths were not more than 0.7nm. The detection limit of the concentration of tung oil adulterated in vegetable oils was lower than 0.1%.

Food Analysis↗