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Biomedical subjects

C Huang

Publications and source records attributed to C Huang.

At least 343 records · Page 19Linked to original sources
PubMed1997

Neural regulation of kidney function by the somatosensory system in normotensive and hypertensive rats.

This investigation examined the renal sympathetic nerve and renal excretory responses to somatosensory stimulation in normotensive and stroke-prone spontaneously hypertensive rats (SHRSP). Somatosensory activation was achieved by either subcutaneous capsaicin administration or exposure of the airways tract to irritant fumes from acetic acid in chloralose-urethan-anesthetized animals. In Wistar rats, blood pressure increased between 10 and 20% (P < 0.001-0.01), renal perfusion pressure was maintained unchanged, renal hemodynamics were unaltered, and urine flow and sodium excretion were decreased by 25 to 50% (P < 0.001-0.05). In the SHRSP, the somatosensory-induced increases in blood pressure were slightly larger (approximately 15-20% P < 0.05) than those of the Wistar rats, whereas the excretory responses were one-half those of the normotensive animals (P < 0.05). The somatosensory challenges reflexly increased integrated renal sympathetic nerve activity in both normotensive and hypertensive rats. The power spectral analysis demonstrated that the increases in percentage power at heart rate frequency and total power were two to three times more (P < 0.05) in the Wistar rats compared with the SHRSP. The reduced ability of the SHRSP to modulate the energy in the renal sympathetic nerve signal at heart rate frequency might explain in part the attenuated functional responses to the somatosensory challenges.

Acetic Acid↗
PubMed1997

Action of 3 tyrphostin derivatives on casein kinase II from rat liver.

AIM: To study the action of tyrphostin on casein kinase (CK) II. METHODS: CK II was partially purified from rat livers by sequential DE52 and heparin-Sepharose chromatography. CK II activity was assayed by incubating CK II with dephosphorylated casein and [gamma-32P]ATP. RESULTS: AG34 inhibited the activity of CK II with IC50 33 (27-41) mumol.L-1. Both AG372 (121 mumol.L-1) and AG1112 (150 mumol.L-1) displayed inhibitory effects on the activity of CK II. Kinetic studies of AG34 on CK II showed that it was noncompetitive with casein and ATP. CONCLUSION: AG34, AG372, and AG1112 were potent inhibitors of CK II, and the inhibitory action of AG34 was noncompetitive with casein and ATP.

Animals↗
PubMed1997

[Relationship between p16 and Rb protein expression in astrocytomas].

OBJECTIVE: p16 and Rb protein were examined in primary astrocytomas in order to study the correlation between p16 and Rb proteins. METHODS: p16 and Rb pretoin were immunostained by SP immunohistochemical method in the sections of formalin fixed paraffin embedded tumor tissue from 102 patients with astrocytoma brain tumors. RESULTS: p16 and Rb protein were expressed in all low grade (WHO Grade I and II) astrocytomas but only in 48.1% and 57.4% astrocytomas of Grade III and Grade IV respectively, in which, 24/31 of Rb protein positive tumors showed null or low expression of p16 protein, while 19/23 of Rb negative tumors were associated with positive or high level expression of p16 protein. CONCLUSIONS: (a) p16 and Rb proteins were both involved in astrocytoma progression. (b) Negatively correlated pressionof p16 and Rb protein might be one of characteristics of malignant astrocytoma.

Astrocytoma↗
PubMed1997

[The significance of use of anti-intrarenal artery spasm in renal allografts with HAR like manifestation].

In the past, severe ischemia of unknown cause in renal allografts after restoration of renal blood flow was regarded as a sign of hyperacute rejection (HAR) or other irreversible lesions, so that the grafts were usually excised during the operation. From January, 1994 to April, 1996, 8 cases of renal allografts with ischemia as described above were encountered in our hospital. Measures of anti-intrarenal artery spasm (IRAS) were taken to those grafts. Except that three grafts of HAR were excised, ischemia disappeared an renal functions recovered in 5 grafts. It suggested that ischemia of the five grafts was caused by IRAS. Thus, IRAS should be taken into account for renal allografts with severe ischemia of unknown cause and early anti-IRAS is essential for the diagnosis and treatment of IRAS.

Adult↗
PubMed1997

[Preparation of monoclonal antibodies to barley yellow mosaic virus].

Using hybridoma techniques, six hybridoma celllines: 4D6, 4D4, 4F10, 3H6, 3H8 and 4E9 secreting monoclonal antibodies to Shanghai Isolate of Barley yellow mosaic virus (BaYMV) were prepared by fusion between myeloma cells NS-1 and spleen cells of BALB/C mouse immunized with BaYMV. The subclasses of monoclonal antibodies obtained belong to IgG2a. The cross-reaction test with different viruses (SMV, TMV and three isolates of TuMV) showed that six monoclonal antibodies were specific to BaYMV. The titers of six monoclonal antibodies to BaYMV in their cell cultured supernatauts were 1:1-5 x 10(4), and that of 4F10 in ascitic fluid was 1:6.4 x 10(5) by using indirected ELISA test respectively.

English Abstract↗
PubMed1997

[Arginine-glutamine replacement at residue 57 of NADH-cytochrome b5 reductase in Chinese hereditary methemoglobinemia].

OBJECTIVE: To elucidate the molecular mechanism of NADH cytochrome b5 reductase (Cytb5R) deficiency in hereditary methemoglobinemia. METHODS: Cytb5R cDNA was cloned from white blood cells from patient with hereditary methemoglobinemia by RT-PCR method, and the genomic DNA from 3 pedigrees with hereditary methemoglobinemia were analyzed by restriction enzyme analysis. RESULTS: On sequencing the cDNA, two missense mutation were found. One is CGG-->CAG at codon 57 of exon 3, caused Arg-Gln replacement. The other is GAG-->GGG at codon 222 of exon 8. The former mutation abolishes the Msp I recognition site which was confirmed in two of three hereditary methemoglobinemia family. The latter mutation generates a recognition site for Bsi Y I. Amplification of exon 8 by PCR followed by digestion with Bsi Y I revealed no mutation in all patients from the three families. CONCLUSION: Arg57-Gln replacement is responsible for Cytb5R deficiency in the two Chinese pedigrees.

Adult↗
PubMed1997

[The development and efficacy tests for the autoclave indicator tape].

The paper describes the development and efficacy teats for the autoclave indicator tape which has specially effects on temperature of pressure steam, time of persistence and air of remainder in the autoclave, and quick, simple and advanced charater for indirectly testing the quality of autoclave sterilization.

Indicators and Reagents↗
PubMed1996

Ultraviolet B-induced activated protein-1 activation does not require epidermal growth factor receptor but is blocked by a dominant negative PKClambda/iota.

The exposure of mammalian cells to UV irradiation leads to the activation of transcription factors such as activated protein-1 (AP-1) and NFkappaB. It is postulated that epidermal growth factor (EGF) receptor, but not protein kinase C (PKC), is the major membrane mediator in UV-induced signal transduction. Since UVB is responsible for most of the carcinogenic effects of sun exposure, we investigated the role of EGF receptors and PKC in UVB-induced AP-1 activation. Our results indicated that while the down-regulation of novel PKC (nPKC) and conventional PKC (cPKC) by pretreatment of cells with 12-O-tetradecanoyl phorbol-13-acetate cannot block UVB-induced AP-1 activity, it can block 12-O-tetradecanoyl phorbol-13-acetate-induced AP-1 activity. Further, the dominant negative mutant PKClambda/iota blocked UVB-induced AP-1 activity in all doses and time courses studied. In contrast, UVB-induced AP-1 activity from cells devoid of EGF receptor (B82) was not significantly different from that of the stable transfectants with a kinase-deficient EGF receptor (B82M721) or those with a wild-type EGF receptor (B82L) at all UVB irradiation doses and time courses studied. All of this evidence indicated that aPKC, but not EGF receptor, is involved in UVB-induced AP-1 activation.

Animals↗
PubMed1996

Vertebral fracture and other predictors of physical impairment and health care utilization.

BACKGROUND: A better understanding of the impact of vertebral fractures on physical functioning would help clinicians gauge the potential benefits of identifying patients at high risk and prevent vertebral fractures due to osteoporosis. METHODS: We explored the associations of vertebral fractures and other potential predictors with physical impairment and health care utilization based on the data collected from 569 postmenopausal Japanese American participants of the Hawaii Osteoporosis Study, aged from 55 to 93 years. A major advantage of this study is the availability of serial spine radiographs for all participants. All vertebral fractures could be identified and the fracture dates estimated. RESULTS: Poor physical functioning was related to increases in number of recent vertebral fractures, age, body mass index, and number of other painful joints. Recent vertebral fractures had a strong impact on bending- and walking-related activities. For each recent vertebral fracture, the odds of impairment increased about 2 times and the odds of a physician visit for back pain increased 3.6 times. The number of recent vertebral fractures was also a significant predictor of poor performance in functional reach and walking speed tests. The effects of vertebral fractures on physical functioning may persist for several years. CONCLUSIONS: Recent vertebral fractures may lead to long-term poor physical functioning. Clinicians should take appropriate measures to identify those at risk, to prevent progression of osteoporosis, and to limit associated disability.

Activities of Daily Living↗
PubMed1996

Control of endogenous mouse mammary tumor virus superantigen expression in SJL lymphomas by a promoter within the env region.

SJL mouse lymphomas (reticulum cell sarcomas, or RCSs) of germinal center B cell origin express an endogenous mouse mammary tumor virus (mtv-29) superantigen (vSAg) that stimulates Vbeta16+ T cells to produce cytokines essential for RCS growth. Normal or LPS-activated SJL/J B cells contain two to three larger mRNAs for mouse mammary tumor virus-long terminal repeat (LTR) but not the 1.8-kb mRNA, which is prominent in RCS cells and encodes the vSAg-29. mRNAs from RCS and normal lymphoid cells were characterized by Northern hybridization using DNA probes from various regions of mtv-29, as well as by reverse transcription PCR, RNase protection, and primer extension. The larger mtv-29 transcripts, coding for envelope protein, are initiated in the 5' LTR, as expected. Surprisingly, the 1.8-kb mRNA, encoding the open reading frame of the LTR, is initiated in the middle of the env region and spliced in the 3' env. This is the first report of an mtv-vSAg transcript that is not controlled by promoter(s) located in the 5' LTR. The env initiation site appears identical to that of the mouse mammary tumor virus env transcriptional activator-directed PMA-induced defective LTR transcript in the C57BL6 T cell lymphoma, EL-4. The stimulus independence, B lymphoma specificity, and absence of deletions within either the 5' or 3' LTR regions of mtv-29 in RCS distinguish the situation in RCS cells from that in EL-4. These findings suggest that the novel mtv-29-vSAg transcript reflects an RCS-cell-specific regulation of transcription.

Animals↗
PubMed1996

A calorimetric study of binary mixtures of saturated and monounsaturated mixed-chain phosphatidylethanolamines.

In this study, we have semisynthesized the following three molecular species of mixed-chain phosphatidylethanolamine: C(22):C(12)PE, C(16):C(18:1 delta 9)PE, and C(10):C(24:1 delta 15)PE. These lipids share a common structural characteristic, that is, they all have the same total number of carbon atoms in their acyl chains. Aqueous dispersions prepared from three sets of binary lipid mixtures, C(16):C(18:1 delta 9)PE/C(22):C(12)PE, C(10):C(24:1 delta 15)PE/C(22):C(12)PE, and C(16):C(18:1 delta 9)PE/C(10):C(24:1 delta 15)PE, were studied by high-resolution differential scanning calorimetry, leading to the construction of three temperature-composition phase diagrams. A computer program developed on the basis of the thermodynamic equations for non-ideality of mixing (or Brigg-Williams approximation) was applied to fit the calorimetric data, yielding the non-ideality parameters of mixing in the gel and the liquid-crystalline bilayers (pG and pL). Based on the shapes of these phase diagrams and the values of pG and pL, it is concluded that any two of the three molecular species of phosphatidylethanolamines under study can mix nearly ideally in the bilayer plane of the liquid-crystalline bilayer. However, these binary lipid mixtures do exhibit the gel-gel phase immiscibility over an extensive compositional region in the gel-state bilayer. By comparison with experimental data obtained with binary mixtures of saturated identical-chain phospholipids, we can conclude that mixed-chain cis-monounsaturated lipid molecules and saturated lipid molecules are highly demixed in the same two-dimensional plane of the gel-state bilayer, although the bilayer thickness difference between the lipid bilayer composed of cis-monounsaturated lipids and that of saturated lipids may be only one or two C-C bond lengths at T < Tm.

Calorimetry, Differential Scanning↗
PubMed1996

Fate of two mast cell tryptases in V3 mastocytosis and normal BALB/c mice undergoing passive systemic anaphylaxis: prolonged retention of exocytosed mMCP-6 in connective tissues, and rapid accumulation of enzymatically active mMCP-7 in the blood.

The mouse mast cell protease granule tryptases designated mMCP-6 and mMCP-7 are encoded by highly homologous genes that reside on chromosome 17. Because these proteases are released when mast cells are activated, we sought a basis for distinctive functions by examining their fates in mice undergoing passive systemic anaphylaxis. 10 min-1 h after antigen (Ag) was administered to immunoglobulin (Ig)E-sensitized mice, numerous protease/proteoglycan macromolecular complexes appeared in the extracellular matrix adjacent to most tongue and heart mast cells of normal BALB/c mice and most spleen and liver mast cells of V3 mastocytosis mice. These complexes could be intensively stained by anti-mMCP-6 Ig but not by anti-mMCP-7 Ig. Shortly after Ag challenge of V3 mastocytosis mice, large amounts of properly folded, enzymatically active mMCP-7 were detected in the plasma. This plasma-localized tryptase was approximately 150 kD in its multimeric state and approximately 32 kD in its monomeric state, possessed an NH2 terminus identical to that of mature mMCP-7, and was not covalently bound to any protease inhibitor. Comparative protein modeling and electrostatic calculations disclosed that mMCP-6 contains a prominent Lys/Arg-rich domain on its surface, distant from the active site. The absence of this domain in mMCP-7 provides an explanation for its selective dissociation from the exocytosed macromolecular complex. The retention of exocytosed mMCP-6 in the extracellular matrix around activated tissue mast cells suggests a local action. In contrast, the rapid dissipation of mMCP-7 from granule cores and its inability to be inactivated by circulating protease inhibitors suggests that this tryptase cleaves proteins located at more distal sites.

Anaphylaxis↗
PubMed1996

A kinase-encoding gene from Colletotrichum trifolii complements a colonial growth mutant of Neurospora crassa.

Colletotrichum trifolii is a fungal pathogen which is responsible for anthracnose disease of alfalfa. To initiate research on molecular communication in this fungus, a kinase-encoding gene (TB3) and the corresponding cDNA were cloned and sequenced. The deduced amino acid sequence of TB3 closely resembles that of a Neurospora crassa serine/threonine protein kinase, COT1, required for hyphal elongation and branching. The C-terminal catalytic domains of TB3 and COT1 are highly conserved but the N-terminal regions are divergent, particularly in the homopolymeric glutamine repeats of TB3. Northern analysis indicated that TB3 expression was highest 1 h after inducing conidial germination and 1 h before germ tubes were first observed. Expression of TB3 transcripts returned to constitutive levels by 4 h after induction of germination. TB3 complemented the cot-I mutant of Neurospora crassa, demonstrating the functional conservation of this kinase between a pathogenic and a saprophytic fungus.

Amino Acid Sequence↗
PubMed1996

Detection of California serogroup Bunyaviruses in tissue culture and mosquito pools by PCR.

A reverse transcription-polymerase chain reaction (RT-PCR) protocol was developed for rapid detection of 14 California serogroup viruses using universal primer pairs. These primers are specific for the small RNA (S RNA) and middle RNA (M RNA) segments. The method has been employed to detect Jamestown Canyon (JC) virus in naturally infected mosquitoes. With this technique, it is possible to detect virus in an amount of material equivalent to as little as 0.03 mosquito.

Animals↗