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Biomedical subjects

F Huang

Publications and source records attributed to F Huang.

At least 109 records · Page 6Linked to original sources
PubMed1998

Analysis of the 5' flanking sequence of the human norepinephrine transporter gene.

The human norepinephrine transporter (NET) gene was cloned and structurally analyzed. The far 5' fragment containing exon 1 (a non-coding exon) and exon 2 was sequenced. The transcription start site of the gene in human brain stem tissue was determined by primer extension analysis. It was found that the gene could be transcribed from multiple starting points. The 5' flanking sequence contains a proximal G-C rich region, one possible GSG element and several SP1 sites. However it does not contain TATA box and CAAT box motifs. Gel shift analysis with nuclear extracts from different tissues of mouse shows that the G-C rich region may be involved in tissue specific expression of the gene.

Animals↗
PubMed1998

Val 70, Phe 72 and the last seven amino acid residues of C-terminal are essential to the function of norepinephrine transporter.

The norepinephrine transporter(NET) is a member of the Na+/Cl- dependent neurotransmitter transporter family and constitutes the target of several clinically important antidepressants. To delineate the critical amino acid residues and the function of C-terminal in regulating transport activity of NET, here we constructed two site mutants (V70F, F72V; V70I, F72V) and one C-terminal truncated mutant (delta 611-617). The wild type and mutants of NET were expressed in Xenopus oocytes by injection of their cRNA. We found that all of these mutants lost their transport activity. These results indicate that the amino acid residues of V70 and F72, and the last seven amino acids of C-terminal are essential to the transport activity of NET.

Amino Acid Sequence↗
PubMed1998

Transzygomatic coronoidectomy through an extended coronal incision for treatment of trismus due to an osteochondroma of the coronoid process of the mandible.

Osteochondroma is the most common benign tumor of the skeletal system. In the craniofacial skeleton, however, osteochondroma is uncommon. Even more rare is osteochondroma of the coronoid process. A review of the literature reveals only 31 reported cases of osteochondroma of the coronoid process of the mandible. The preponderance of patients were young men (67.7%) and most presented with a facial deformity. As a benign tumor, the problems with surgical treatment have dealt with the inaccessibility of the lesion and hence the surgical approach of choice. The previous surgical approaches have either been intraoral, external, or a combination of both. We present a transzygomatic approach via a coronal incision that gives excellent access and a good cosmetic result, and protects the facial nerve from damage.

Bone Plates↗
PubMed1998

Immunity in chimpanzees chronically infected with hepatitis C virus: role of minor quasispecies in reinfection.

We have previously reported that chimpanzees chronically infected with hepatitis C virus (HCV) could be reinfected, even with the original infecting strain. In this study we tested the hypothesis that this might reflect the presence of minor quasispecies to which there was little or no immunity. To evaluate this hypothesis, we sequenced multiple clones taken at intervals after primary infection and rechallenge from four chronically infected chimpanzees. The inoculum used in these studies (HCV-H, genotype 1a) revealed 17 separate variants among 46 clones sequenced. Following challenge, each of the four challenged animals showed marked alterations of their quasispecies distribution. The new variants, which appeared 1 to 6 weeks after challenge, were either identical to or closely resembled variants present in the challenge inoculum. These results, paralleled by an increase in viremia in some of the challenged animals, suggest that quasispecies in the challenge inoculum were responsible for signs of reinfection and that there was little immunity. However, the newly emerged quasispecies completely took over infection in only one animal. In the remaining three chimpanzees the prechallenge quasispecies were able to persist. The natural evolution of infection within chimpanzees resulted in variants able to compete with the inoculum variants. Whether through reexposure or the natural progression of infection, newly emerged quasispecies are likely to play a role in the pathogenesis of chronic HCV infection.

Alanine Transaminase↗
PubMed1998

[Study on HCV infection and the distribution of HCV genotypes in different populations in Shenyang area].

3,902 serum samples in different populations were tested for anti-HCV by ELISA. Among 100 samples of them, genotypes of HCV were detected by PCR with type-specific primers. The results showed: a) anti-HCV positive rates in general populations were 0.42%-1.66%; b) anti-HCV positive rates in the group of post-transfusion hepatitis and sporadic hepatitis (excluding HAV, HBV, EBV, CMV infection), hepatitis B post hepatitis cirrhosis (excluding HBV infection) and primary hepatocarcinoma were significantly higher than the group of patients without liver diseases or the group of patients without transfusion (P < 0.01); c) in HCV genotyping, HCV-II, HCV-III, II/III mixed type were 58%, 27%, 14% respectively. The rate of infection with HCV-III, was 80% in normal population but 91.7% with type II HCV in the group of patients with cirrhosis. These results suggested: (1) patients with different liver diseases were under high risk of HCV infection; (2) type HCV-II was predominant followed by HCV-III as well as II/III mixed in HCV genotype distribution of Shenyang area. Different genotypes of HCV might be related to the severity of hepatitis C.

Adolescent↗
PubMed1998

Effect of mild hypothermia on the changes of cerebral blood flow, brain blood barrier and neuronal injuries following reperfusion of focal cerebral ischemia in rats.

OBJECTIVE: To compare the effects of mild hypothermia induced in different time courses on rats subjected to 3 hours (h) of ischemia followed by 3 h or 72 h of reperfusion. METHODS: Eighty male Sprague-Dawley rats were divided into three mild hypothermic (MHT, 32 +/- 0.2 degrees C) groups, including intra-ischemia (MHTi), intra-reperfusion (MHTr), and intra-ischemia/reperfusion (MHTi + r) group, and one normothermic group (NT, 37 +/- 0.2 degrees C) as the control. Reversible focal ischemia was carried out in rats with suture model. The cortical blood flow was measured during 3 h of ischemia followed by 3 h of reperfusion. The permeability of brain blood barrier (BBB) was estimated after 3 h of reperfusion. The infarct volume was measured at 72 h after reperfusion to determine the effects of MHT. RESULTS: The acute post-ischemic hyperperfusion and delayed hypoperfusion in ischemic perifocal region and sustained hypoperfusion in ischemic core were inhibited in MHTi + r and MHTi rats (P < 0.05). MHTi + r protection on post-ischemic progressive hypoperfusion in the perifocal region was more effective than that of MHTi (P < 0.05). The BBB disruption and the infarct volume were significantly reduced in both MHTi and MHTi + r groups (P < 0.05), especially in the MHTi + r rats. CONCLUSIONS: This study demonstrates that MHTi + r has more substantial protective effects on reducing ischemia/reperfusion injury than MHTi. It may inhibit post-ischemic hyperperfusion and delayed or sustained hypoperfusion in ischemic perifocal regions, and reduce brain blood barrier disruption in the cortex region.

Animals↗
PubMed1998

[Restoration of supination of forearm by flexor carpi radialis transfer].

The dysfunction of supination of forearm following injury of brachial plexus or poliomyelitis always affects the function of hand. To find the dynamic muscle for restoration of the supination, the flexor carpi radialis was investigated on fifty male cadavers. The blood supply of the muscle was polygenic, mainly derived from the humoral and radial arteries. The movement of the muscle was innervated by median nerve. If the proximal 1/3 belly of the muscle was reserved, the blood supply and innervation of the complete muscle was reserved. According to the anatomic data, the operative procedure was designed as following: transfer the distal 2/3 of flexor carpi radialis over the ulnar aspect of the forearm to the dorsal-radial side, the tendon was fixed on the radius shaft 6 to 10 cm proximal to the styloid process with forearm in full supination. Four patients were treated and after followed up for 3.2 years average, the supination restored. It was discussed that in case of paralysis of the flexor carpi ulnaris and pronator teres, the optimal choice to restore the supination would be flexor carpi radialis.

Adult↗
PubMed1998

[Etiology and clinical analysis of epididymal mass].

The etiology and clinical pathological analysis of 147 cases of epididymal mass were presented. The result showed that the most common mass in inflammatory (66%), and the majority was tuberculosis, the next was cystic diseases (30%). However, neoplasm was relatively less and malignant mass was rare. The diagnosis can be established by careful history, physical examination, and BUS. The selective surgery depends on the nature of diseases, the demand of the patients and the effect of conservative therapy.

Adenomatoid Tumor↗
PubMed1998

[Free jejunal grafts for reconstruction of pharynx and cervical esophasgus].

Eleven patients with hypopharyngeal carcinoma were treated surgically and the pharynx and cervical esophagus were reconstructed with free jejunal grafts through the technique of microvascular anastomosis. The microvascular anastomosis were all successful and the patients all survived the operations. The operations were performed at one time with only a few complications. There were 2 cases of pharyngeal fistula and 1 case of bleeding from the anastomotic site. The patients could eat by their mouths and swallow very well just 15 days after the operation. The 3-year suvival rate was 36%. The main causes of death were the recurrence and the metastasis to the cervical lymph nodes. We came to the conclusion that the operation is safe with high success rate and no mortality during operation, and it is less injurious than the gastropharyngeal anastomosis. The key point of the operation is the surgeon's mastery of the microvascular anastomosis technique.

Aged↗
PubMed1998

[Endoscopic variceal ligation combined with partial splenic embolization: preliminary clinical results].

Endoscopic variceal ligation combined with partial splenic embolization (EVL-PSE) was performed in a group of 13 patients with esophageal variceal bleeding and hypersplenism due to portal hypertension from January 1997 to March 1998. PSE was performed one to two weeks before or one week after initial EVL, and a range of 30% to 60% of the splenic parenchyma was embolized. Repeated EVL was performed at two week intervals until the varices were eradicated. Active bleeding in the nine patients was successfully controlled and all the varices of the 13 patients were eradicated after EVL-PSE. Eradication of the varices required two to five(mean 3.1) EVL sessions, follow-up ranging from 2 to 16 months(mean 6.9 months). In all but one case, no rebleeding occurred. All patients after PSE showed a good response on peripheral blood cell count and reduction of splenomegaly. No major complication or death related to the combination therapy was observed. Preliminary results in this study show that this combination therapy may result in more rapid eradication of the varices and reduce rebleeding after endoscopic variceal ligation. However, more data and studies may be necessary for further evaluation.

Adult↗
PubMed1998

[The association of HLA-B27 binding peptide and spondylarthropathies].

OBJECTIVE: To explore the association of spondylarthropathies HAL-B27 binding peptide. METHODS: B27 molecules expressed on the B27-T2 mutant cell line do not have peptides. Such empty B27 molecules were not recognized by peptide-dependent monoclonal antibody, B27.M2. Positive B27.M2 reactivity resulted when B27-T2 cells were incubated with peptide RRKAMFEDI derived from Chlamydia hsp60. THe importance of each residue in RRKAMFEDI was analysed by testing analogs in which each of the 9 residues in the peptide was consecutively substituted by 19 other amino acids. RESULTS: B27.M2 reactivity was the highest with arginine in second residue. The reactivities of residues other than arginine were less than 30% of the value with the parent peptide. CONCLUSION: The stringency for other residues was relatively low, indicating that immune recognition of B27-peptide complexes might have rather low stringency for peptide sequences. These peptide residues probably influenced antibody reactivity by inducing conformational changes.

HLA-B27 Antigen↗
PubMed1998

U-74389G suppresses lipid peroxidation and apoptosis following focal cerebral ischemia and reperfusion in rats.

OBJECTIVE: To study the antioxidant and antiapoptotic effects of U-74389G on ischemic brain in rats. METHODS: Right focal cerebral ischemia and reperfusion was induced by suturing in 103 male SD rats weighing 280-310 g. To determine LPO in the cortex and striatum, we randomly divided 78 rats into 5 groups: group 1, sham-operative group (6 rats); group 2, control (18); group 3, U-74389G administration before ischemia (18); group 4, U-74389G administration before reperfusion; group 5, CS-4 vehicle as negative control. Groups 2-5 were further divided into 3 subgroups according to the duration of reperfusion. Another 25 rats were similarly grouped (5) to detect apoptosis with TUNEL stain. RESULTS: The concentrations of MDA in groups 3 and 4 were reduced and the activities of SOD and concentrations of GSH were partially restored as compared with the control group. These effects were more significant in group 3 than in group 4. Otherwise, CS-4 can not provide protective effects. The number of apoptotic cells in groups 3 (P < 0.01) and 4 (P < 0.05) was significantly reduced as compared with the control group. CONCLUSIONS: U-74389G has antioxidant and antiapoptotic effects on ischemic brain in rats. The administration of U-74389G before the onset of ischemia was more useful than that before the onset of reperfusion.

Animals↗
PubMed1998

[Parameters of arterial occlusion during intracranial aneurysm surgery].

OBJECTIVE: To evaluate parameters, owing to temporary and/or permanent intraoperative arterial occlusion, could be related to the postoperative development of ischemic injury. METHOD: During 3-year period between October 1994 and March 1997, 27 patients with intracranial aneurysm were operated on with the aid of temporary and/or permanent arterial occlusion. Continuous intraoperative monitoring lCBF of the territories undergoing occlusion was carried out using LDF. Univariate analysis was used to study the relationship between the study variable and cerebral infarction. These variables included patient age, sexuality, aneurysm size, preoperative Hunt and Hess grades, LDF baseline value, LDF value following arterial occlusion and release of occlusion, the duration of arterial occlusion, the numbers of occlusive episodes, and the degree of arterial occlusion. Student's t-test was used for comparison of continuous variable such as age, and chi-square analysis was used to test the association of categorical variables. RESULT: The LDF value following arterial occlusion or residual lCBF, the duration of arterial occlusion, the numbers of occlusive episodes, and the occlusive degree were found to be significantly related to the postoperative development of ischemic injury. CONCLUSION: The residual lCBF and collateral circulation following arterial occlusion can be evaluated using LDF monitoring. When residual lCBF is more than 50 per cent of the baseline and the duration of arterial occlusion less than 20 minutes, temporary arterial occlusion is safe and does not develop postoperative ischemic injury.

Adolescent↗
PubMed1998

Syntagms in development and evolution.

The genetic analysis of segmentation, neurogenesis, appendage formation and other developmental processes has revealed that the development of Drosophila can be broken down into discrete elementary operations. Thus development can be viewed as a stepwise process where each step is driven by a small group of genes working interactively. García-Bellido proposed that each of these groups be called a "syntagm". In this review, we will describe a series of developmental syntagms, and explore the consequences of this discontinuous organization of the developmental program on evolution.

Animals↗
PubMed1997

A calcium-metalloribozyme with autodecapping and pyrophosphatase activities.

A previously-isolated ribozyme with capping activity has self-decapping activity, here characterized alongside its additional, somewhat parallel, pyrophosphatase reaction. Decapping is 10-50 times slower than the pyrophosphatase activity, depending on pH. The RNA accelerates pyrophosphate release 170 000 times over a control composed of randomized pppRNA, and 5' capped RNA accelerates decapping 1000-fold over random capped RNA. Triphosphate-linked G(5')pppRNA also supports an unusual cap-exchange reaction, exchanging its cap with guanosine 5'-tetraphosphate to form pentaphosphate-linked G(5')pppppRNA. GDP, a capping reactant for the RNA, appears to suppress both decapping and pyrophosphatase activities. Autodecapping and pyrophosphatase activities have in common an unusual divalent metal ion requirement for Ca2+ or less effectively Mn2+, and both are active over a broad pH range of 4.5-9. 0. These characteristics resemble the capping activity of the same RNA. Kinetic analysis reveals a well-defined Ca2+-RNA complex, and Mg2+ and Sr2+ act as competitive inhibitors of Ca2+. A strong Ca2+-binding site is suggested by a low KM of 40-60 microM at pH >/= 7.0. The role of Ca2+ in these reactions can be surmized from literature data on reactivity of nucleotide phosphates. Pyrophosphatase, capping, and decapping activities of isolate 6 RNA are apparently carried out by a single reaction center, whose rate of reaction with all nucleophiles sums to a constant total rate. This suggests a universal rate-limiting step. Versatile activation of alpha-phosphate by this reaction center raises the possibility of combinatorial ribozymes.

Base Sequence↗
PubMed1997

Interaction of the delta-endotoxin CytA from Bacillus thuringiensis var. israelensis with lipid membranes.

We investigated the binding of CytA, a cytolytic delta-endotoxin from Bacillus thuringiensis var. israelensis, to small unilamellar lipid vesicles (SUV) and the accompanying changes in the overall CytA conformation. From the titration of tryptophan fluorescence with SUV, we determined the apparent association constants of 3500 M-1 and 11000 M-1 for the protoxin CytA27 and the proteolytically activated toxin CytA24, respectively. Inclusion of a negatively charged lipid or a positively charged lipid analog in the membrane did not affect the binding parameters, which suggests that membrane binding is not driven by electrostatic interactions. A decrease in the intensity of the CytA tryptophan fluorescence upon interaction with lipids and the absence of a blue shift in remaining fluorescence indicate that the tryptophan-containing regions of the protein do not significantly penetrate into the hydrophobic core of the lipid bilayer. This finding was corroborated by the lack of additional quenching by brominated or spin-labeled lipids, irrespective of the location of the quenching moiety in the depth of the bilayer. However, the interaction with lipids decreases quenching with the soluble quenchers acrylamide and KI, and the remaining fluorescence is blue-shifted. The observed decrease in fluorescence anisotropy upon membrane binding is not consistent with simple immobilization of CytA on the surface of SUV. We showed by FTIR spectroscopy and differential scanning calorimetry (DSC) that binding to the membrane causes a significant loosening of the protein structure. This is consistent with the fluorescence quenching and anisotropy data. Our experiments provide evidence against CytA's substantially penetrating the lipid bilayer and creating well-defined proteinaceous channels.

Bacillus thuringiensis↗
PubMed1997

Versatile 5' phosphoryl coupling of small and large molecules to an RNA.

A Ca2+-requiring catalytic RNA is shown to create 5' phosphate-phosphate linkages with all nucleotides and coenzymes including CoA, nicotinamide adenine dinucleotide phosphate, thiamine phosphate, thiamine pyrophosphate, and flavin mononucleotide. In addition to these small molecules, macromolecules such as RNAs with 5'-diphosphates, and nonnucleotide molecules like Nepsilon-phosphate arginine and 6-phosphate gluconic acid also react. That is, the self-capping RNA isolate 6 is an apparently universal 5' phosphate-linker, reacting with any nucleophile containing an unblocked phosphate. These RNA reactions demonstrate a unique RNA catalytic capability and imply versatile and specific posttranscriptional RNA modification by RNA catalysis.

Calcium↗