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Biomedical subjects

F H Wang

Publications and source records attributed to F H Wang.

At least 19 recordsLinked to original sources
PubMed1998

Galanin modulates 5-hydroxytryptamine functions. Focus on galanin and galanin fragment/5-hydroxytryptamine1A receptor interactions in the brain.

The reciprocal interactions between galanin and 5-HT1A receptors in the rat brain are presented. Galanin and its NH2-terminal fragments antagonize 5-HT1A receptor-mediated transmission at the postjunctional level, whereas galanin receptor activation mimics the inhibitory action of 5-HT1A receptor activation at the soma-dendritic level, leading to reductions of 5-HT metabolism and release. These interactions have been shown in both receptor binding studies and functional studies. In view of the present findings, galanin antagonists may represent a new type of anti-depressant drug, based on the 5-HT hypothesis of depression, by enhancing 5-HT release and postjunctional 5-HT1A-mediated transmission. Moreover, following intracerebroventricular injection galanin was found to be internalized in a population of hippocampal nerve cells mainly representing GABA, somatostatin, and/or NPY-immunoreactive nerve cells. The relevance of these findings is discussed in relation to the concept of volume transmission.

Animals↗
PubMed1998

Ursodeoxycholic acid increased bile flow and affects bile composition in the early postoperative phase following liver transplantation.

Orally given ursodeoxycholic acid (UDCA) has beneficial effects on laboratory parameters in different cholestatic conditions. In order to investigate the effect on early graft function after liver transplantation, 33 patients were randomized to receive either UDCA 15 mg/kg per day or placebo from the 1st postoperative day until 3 months after transplantation. All liver grafts produced bile within 24 h after revascularization. In both groups there was an increasing bile flow each day until day 5 after transplantation. This increase was more pronounced in the UDCA group where the flow on day 2 reached a mean value of 183 +/- 28 ml/day compared to 106 +/- 17 ml/day in the placebo group (P < 0.05). The average daily volume of bile produced during the first 10 days was also found to be higher in the UDCA group compared to the placebo group (242 +/- 20 ml vs 176 +/- 18 ml, P < 0.02). In the UDCA group a significant decrease in total bile acid output between the 5th and 10th postoperative days was found, while in the placebo group the amount of bile acids excreted remained stable over time. The composition of bile differed between the two groups with an increase in the portion of UDCA in the UDCA group from the 2nd postoperative day (25% vs 4.6%, P < 0.0003). The fraction of UDCA then remained high during the whole study period with a peak at day 3 when 38.1 +/- 6.6% of the bile acids consisted of UDCA. In the placebo group, the fraction of UDCA was low from the beginning and diminished further over time. Prophylactic UDCA treatment was found to have a significant positive impact on the ALT level during the 4th and 5th postoperative days, but had no effect on bilirubin or GGT in the early postoperative phase (days 1-10). No differences in cyclosporine requirement were found between the two groups.

Adult↗
PubMed1998

Effects of short-term treatment with pravastatin on the hepatic synthesis of cholesterol and bile acids in gallstone patients.

BACKGROUND: HMG-CoA reductase inhibitors are now the therapy of choice in the treatment of hypercholesterolaemia. The effects of long-term treatment with these substances on plasma lipoproteins, cholesterol metabolism and biliary secretion of lipids have been extensively studied in humans. Much less is known about the effects of short-term treatment. The aim of this study was to determine the time course of the effects of HMG-CoA reductase inhibitors on plasma lipoprotein levels as well as cholesterol and bile acid synthesis in gallstone patients. METHODS: Thirty-six patients undergoing elective cholecystectomy were included in the study. Except for the gallstone disease, these patients were otherwise healthy. Four groups of subjects were treated with the HMG-CoA reductase inhibitor pravastatin (Pravachol), 20 mg twice daily for 12, 24, 48 and 72 h preoperatively. Plasma lipoproteins and plasma levels of lathosterol and 7 alpha-hydroxy-4-cholesten-3-one were determined before initiation of pravastatin treatment and on the morning of the day of the operation, lathosterol reflecting hepatic HMG-CoA reductase activity and 7 alpha-hydroxy-4-cholesten-3-one the activity of cholesterol 7 alpha-hydroxylase, the rate-determining enzyme in bile acid synthesis. RESULTS: All treatment groups displayed a significant decrease in total cholesterol and low-density lipoprotein (LDL)-cholesterol, by about 12% and 17% respectively. Lathosterol was reduced by about 50% in all treatment groups. Of great interest was the finding that 7 alpha-hydroxy-4-cholesten-3-one was unaffected in all treatment groups. CONCLUSION: The results show that short-term pravastatin treatment in gallstone patients rapidly inhibits cholesterol synthesis and lowers plasma LDL-cholesterol levels without effects on bile acid synthesis.

Adult↗
PubMed1998

Intraventricular galanin modulates a 5-HT1A receptor-mediated behavioural response in the rat.

The present studies have examined whether the neuropeptide galanin can modulate brain serotoninergic (5-HT) neurotransmission in vivo and, particularly, 5-HT1A receptor-mediated transmission. For that purpose, we studied the ability of galanin (given bilaterally into the lateral ventricle, i.c.v.) to modify the impairment of passive avoidance retention induced by the selective 5-HT1A agonist 8-hydroxy-2-(di-n-propyloamino)tetralin (8-OH-DPAT) when injected prior to training. This impairment appears to be mainly related to activation of 5-HT1A receptors in the CNS. Galanin dose-dependently (significant at 3.0 nmol/rat) attenuated the passive avoidance impairment (examined 24 h after training) induced by the 0.2 mg/kg dose of 8-OH-DPAT. This 8-OH-DPAT dose produced signs of the 5-HT syndrome indicating a postsynaptic 5-HT1A receptor activation. Furthermore, both the impairment of passive avoidance and the 5-HT syndrome were completely blocked by the 5-HT1A receptor antagonist WAY 100635 (0.1 mg/kg). Galanin (0.3 or 3.0 nmol) or WAY 100635 (0.1 mg/kg) failed by themselves to affect passive avoidance retention. 8-OH-DPAT given at a low dose 0.03 mg/kg, which presumably stimulates somatodendritic 5-HT1A autoreceptors in vivo, did not alter passive avoidance retention or induce any visually detectable signs of the 5-HT syndrome. Galanin (0.3 or 3.0 nmol) given i.c.v. in combination with the 0.03 mg/kg dose of 8-OH-DPAT, did not modify passive avoidance. The immunohistochemical study of the distribution of i.c.v. administered galanin (10 min after infusion) showed a strong diffuse labelling in the periventricular zone (100-200 microm) of the lateral ventricle. Furthermore, in the dorsal and ventral hippocampus galanin-immunoreactive nerve cells appeared both in the dentate gyrus and the CA1, CA2 and CA3 layers of the hippocampus. In the septum only endogenous fibres could be seen while in the caudal amygdala also galanin-immunoreactive nerve cells were visualized far away from the labelled periventricular zone. At the level of the dorsal raphe nucleus a thin periventricular zone of galanin immunoreactivity was seen but no labelling of cells. These results suggest that galanin can modulate postsynaptic 5-HT1A receptor transmission in vivo in discrete cell populations in forebrain regions such as the dorsal and ventral hippocampus and parts of the amygdala. The indication that galanin administered intracerebroventrically may be taken up in certain populations of nerve terminals in the periventricular zone for retrograde transport suggests that this peptide may also affect intracellular events.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1998

Ionizing radiation and TNF-alpha and stimulated expression of alpha1-antichymotrypsin gene in human squamous carcinoma cells.

Alpha-1 antichymotrypsin (ACT), a serine protease inhibitor, has been detected in several epithelial tumor cell types, but its role in response to therapy is not clear. We report here that exposure of primary head and neck squamous cell carcinoma (HNSCC)-derived cells (PCI-04A) to ionizing radiation (IR) or tumor necrosis factor-alpha (TNF-alpha) resulted in an increased level of ACT mRNA, although the induction patterns were different. IR treatment caused a transient stimulation of ACT mRNA, peaking at 3 h post-irradiation, whereas TNF-alpha-inducible ACT gene expression lasted for up to 24 h. The ACT mRNA was expressed in several epithelial and non-epithelial tumor cell types, and in different normal human tissues. In addition, when the ACT gene expression in PCI-04A cells was compared with the matched (from the same patient) metastatic HNSCC-derived cells (PCI-04B), increased steady-state level of the ACT mRNA was observed in PCI-04B cells. Taken together, these findings suggest that ACT may serve as an important marker for prognosis and therapy selection in HNSCC.

Carcinoma, Squamous Cell↗
PubMed1997

Circulating markers for biosynthesis of cholesterol and bile acids are not depressed in asymptomatic gallstone subjects.

BACKGROUND/AIMS: Cholesterol gallstone disease is often associated with an increased biliary secretion rate of cholesterol, which may be due to abnormalities in hepatic cholesterol metabolism. The aim of the present study was to investigate whether gallstone subjects may have an underlying defect in hepatic cholesterol and bile acid formation. METHODS: In 41 asymptomatic gallstone subjects, randomly selected from a population of both sexes 40 and 60 years of age, and in 72 age- and sex-matched controls, plasma levels of lathosterol (reflecting hepatic HMG CoA reductase activity) and 7alpha-hydroxy-4-cholesten-3-one (reflecting cholesterol 7alpha-hydroxylase activity) were analysed. In a subgroup of gallstone subjects and controls, plasma levels of 27-hydroxy cholesterol were also determined. RESULTS: The gallstone subjects had normal plasma levels of cholesterol but displayed 20-25% higher plasma levels of triglycerides compared with the controls. The plasma level of lathosterol was not significantly different between the two groups of subjects whereas the plasma level of 7alpha-hydroxy-4-cholesten-3-one was about 40% higher in the gallstone subjects compared with the controls. Positive correlations were obtained between plasma levels of 7alpha-hydroxy-4-cholesten-3-one and triglycerides in both groups of subjects. The plasma level of 27-hydroxy cholesterol was similar in gallstone subjects and controls. CONCLUSIONS: The previously reported hypersecretion of cholesterol in gallstone patients is not due to a single metabolic defect leading to increased hepatic synthesis of cholesterol or decreased catabolism of cholesterol to bile acids via 7alpha-hydroxylation or 27-hydroxylation of cholesterol.

Adult↗
PubMed1997

Identification of seven differentially displayed transcripts in human primary and matched metastatic head and neck squamous cell carcinoma cell lines: implications in metastasis and/or radiation response.

The patterns of differential gene expression were examined in two primary (A's) and two matched-metastatic (B's) head and neck squamous cell carcinoma (HNSCC) cell lines by differential display of mRNAs and northern blot hybridisation. Three cell lines used (PCI-04A, PCI-04B and PCI-06A) were established independently prior to therapy, whereas one cell line (PCI-06B) was established from a recurrent tumor after radiation therapy. A total of seven differentially displayed mRNA clones were identified, of which six clones were obtained by comparison of PCI-06A cells with PCI-06B cells (SCC-S1a/b, SCC-1c, and SCC-S2, PCI-06B; SCC-S3 to SCC-S5, PCI-06A), and one clone was obtained from the PCI-04A and PCI-04B match (SCC-Sa, PCI-04B). Based on the DNA database search for homology to the known sequences, six of the seven partial cDNA clones (SCC-S1a/b, SCC-1c, SCC-S2 to SCC-S4, and SCC-Sa may represent novel genes, whereas one cDNA clone (SCC-S5) shows significant homology to the HLA class II antigen gene (DPW2 beta chain). Each of the seven clones revealed preferential expression by northern blotting in the cell line of origin as compared to the matched counterpart. The transcripts ranged in size from approximately 7.0 Kb to 0.5 Kb. Interestingly, the SCC-Sa clone was preferentially expressed in both metastatic cell lines compared to the primary tumour-derived cell lines. We conclude that the SCC-Sa gene may be more commonly involved in tumour metastasis, whereas expression of the other genes (SCC-S1a/b, SCC-S1c, SCC-S2-SCC-S5) may be associated with metastasis and/or response of HNSCC to ionising radiation.

Base Sequence↗
PubMed1997

Antisense raf oligodeoxyribonucleotide is protected by liposomal encapsulation and inhibits Raf-1 protein expression in vitro and in vivo: implication for gene therapy of radioresistant cancer.

We have redesigned cationic liposomes by using a combination of dimethyldioctadecyl ammonium bromide, phosphatidylcholine and cholesterol to enhance the in vitro and in vivo effectiveness of antisense raf oligodeoxyribonucleotide (ODN). Circulating ODNs carried in vivo by liposomes were intact for at least 24 h, while free ODNs were undetectable after 5 min. Liposome-encapsulated antisense raf ODN (LE-ATG-AS) inhibited Raf-1 protein expression in vitro and in vivo. Furthermore, radioresistant tumor cells treated with LE-ATG-AS raf ODN were sensitized to ionizing radiation. These data provide new information for the delivery and potency of antisense ODN in vivo, and support the use of LE-ATG-AS raf ODN for gene therapy of radioresistant cancer.

Animals↗
PubMed1997

The effect of vitamin C in high doses on plasma and biliary lipid composition in patients with cholesterol gallstones: prolongation of the nucleation time.

Vitamin C deficiency in guinea pigs leads to cholesterol supersaturation of bile and formation of cholesterol gallstones. It has been suggested that there may also exist an association between vitamin C and cholesterol gallstones in man, but such a relationship has not been studied in gallstone patients. In order to study the possible effects of vitamin C on gallstone disease in humans, plasma lipid levels, hepatic cholesterol metabolism, biliary lipid composition, cholesterol saturation and nucleation time of gallbladder bile were analysed in 16 consecutive gallstone patients, who were planned for laparoscopic cholecystectomy and were treated with vitamin C (500 mg, four times a day) for 2 weeks before surgery. The plasma concentration of vitamin C increased by 42% in the treatment group. The concentrations of plasma lipids did not differ before and after vitamin C treatment; nor did the plasma levels of lathosterol and 7 alpha-hydroxy-4-cholesten-3-one, reflecting cholesterol and bile acid synthesis respectively. The relative concentrations of cholesterol, bile acids and cholesterol concentration of bile did not differ significantly between the two groups, but the relative concentration of phospholipids was slightly higher in the treated group. The bile acid composition was changed; the percentage of cholic acid being lower and those of deoxycholic acid, ursodeoxycholic acid and lithocholic acid higher in the vitamin C-treated patients compared with the untreated group. The nucleation time was significantly longer in the treatment group (7 days) compared with the untreated group (2 days). Our findings indicate that vitamin C supplementation may also influence the conditions for cholesterol gallstone formation in humans.

Ascorbic Acid↗
PubMed1997

Ionizing radiation and TNF-alpha stimulate gene expression of a Thr/Tyr-protein phosphatase HVH1 and inhibitory factor IkappaB alpha in human squamous carcinoma cells.

Exposure of cells to ionizing radiation (IR) or tumor necrosis factor-alpha (TNF-alpha) results in the stimulation of the DNA binding activities of transcription factors, AP-1 and NF-kappaB. HVH1/CL100, a dual specificity protein phosphatase, may attenuate the AP-1 response by dephosphorylating a key upstream element, mitogen-activated protein kinase (MAPK). The members of IkappaB family of proteins regulate the NF-kappaB response. We examined the effects of IR and TNF-alpha on HVH1 and IkappaB alpha gene expression. Our data demonstrate that IR or TNF-alpha treatment of head and neck squamous carcinoma cells (PCI-04A) increased the steady-state levels of HVH1 and IkappaB alpha mRNAs; however, the induction patterns were different. TNF-alpha treatment led to a relatively prolonged stimulation of HVH1 and IkappaB alpha mRNAs lasting at least 7 h, while IR caused a transient stimulation of these mRNAs and the expression returned to basal levels within 6 h post-IR treatment. Treatment of cells with cycloheximide did not prevent the IR orTNF-alpha-inducible expression of HVH1 and IkappaB alpha genes, indicating that these responses were independent of the new protein synthesis. These data imply that protein phosphatase HVH1 and regulatory factor IkappaB alpha may play important roles in cellular response to IR and TNF-alpha. In addition, the kinetics of responsiveness indicates that the mechanisms of IR and TNF-alpha-induced signalling are distinct.

Blotting, Northern↗
PubMed1997

Constitutive modulation of Raf-1 protein kinase is associated with differential gene expression of several known and unknown genes.

BACKGROUND: Raf-1, a cytoplasmic serine/threonine protein kinase, plays an important role in mitogen- and damage-responsive cellular signal transduction pathways. Consistent with this notion is the fact that constitutive modulation of expression and/or activity of Raf-1 protein kinase modifies cell growth, proliferation, and cell survival. Although these effects are controlled at least in part by transcriptional mechanisms, the role of Raf-1 in the regulation of specific gene expression is unclear. MATERIALS AND METHODS: Differential display of mRNA was used to identify the genes differentially expressed in human head and neck squamous carcinoma cells (PCI-06A) transfected with either the antisense c-raf-1 cDNA (PCI-06A-Raf(AS)), or a portion of cDNA coding for the kinase domain of Raf-1 (PCI-06A-Raf(K)). The differentially expressed fragments were cloned and sequenced, and they were used as probes to compare the expression patterns in parent transfectants by Northern blot analysis. In addition, expression patterns of the novel genes were examined in normal tissues and cancer cell lines. RESULTS: Six differentially expressed cDNA fragments were identified and sequenced. Northern blot analysis revealed that four of these fragments representing human alpha 1-antichymotrypsin (alpha 1-ACT), mitochondrial cytochrome c oxidase subunit II (COX-II), and two as-yet unidentified cDNAs (KAS-110 and KAS-111) were relatively overexpressed in PCI-06A-Raf(AS) transfectants compared with PCI-06A-Raf(K) transfectants. The other two cDNA fragments representing human elongation factor-1 alpha (HEF-1 alpha) and ornithine decarboxylase antizyme (OAz) were overexpressed in PCI-06A-Raf(K) transfectants compared with PCI-06A-Raf(AS) transfectants. The KAS-110 (114 bp) and KAS-111 (202 bp) cDNAs did not show significant matches with sequences in the GenEMBL, TIGR, and HGS DNA databases, and these may represent novel genes. The KAS-110 and KAS-111 transcripts, approximately 0.9 kb and approximately 0.5 kb, were observed in most normal tissues and several cancer cell types, indicating their housekeeping function. CONCLUSIONS: This study reports novel components of the Raf-1 signaling pathway. alpha 1-ACT, HEF-1 alpha, COX-II, and OAz have been previously implicated in diverse cellular responses including transformation, energy metabolism, and cell survival. Our data suggest that expression of these genes may play a role in the Raf-1-mediated biological activity of PCI-06A cells. The KAS-110 and KAS-111 cDNAs represent unknown genes, and further investigations are necessary to determine their role in the cellular response. Identification of specific targets may provide useful markers for prognosis and therapy selection in squamous cell carcinoma.

Base Sequence↗
PubMed1996

The homeodomain region of Rag-1 reveals the parallel mechanisms of bacterial and V(D)J recombination.

The V(D)J recombinase subunits Rag-1 and Rag-2 mediate assembly of antigen receptor gene segments. We studied the mechanisms of DNA recognition by Rag-1/Rag-2 using surface plasmon resonance. The critical step for signal recognition is binding of Rag-1 to the nonamer. This is achieved by a region of Rag-1 homologous to the DNA-binding domain of the Hin family of bacterial invertases and to homeodomain proteins. Strikingly, the Hin homeodomain can functionally substitute for the Rag-1 homologous region. Rag-1 also interacts with the heptamer but with low affinity. Rag-2 shows no direct binding to DNA. Once the Rag-1/Rag-2 complex is engaged on the DNA, subsequent cleavage is directed by the heptamer sequence. This order of events remarkably parallels mechanisms that mediate transposition in bacteria and nematodes.

Amino Acid Sequence↗
PubMed1995

Brown-Séquard syndrome associated with Horner's syndrome in cervical epidural hematoma.

STUDY DESIGN: This report analyzed the likely locations of lesions that cause a combination of Horner's and Brown-Séquard syndromes. One must know the anatomic structure of spinal cord and the sympathetic nerve chain. OBJECTIVES: A hypertensive patient had Brown-Séquard and Horner's syndromes after neck trauma. The magnetic resonance imaging and surgical findings showed the correlation between the clinical symptoms and the likely lesion. METHODS: The patient underwent right hemilaminectomy from C2 to C6 with total removal of hematoma. CONCLUSION: The spinal epidural hematoma rarely is a surgical emergency. The patient presented with Brown-Séquard and Horner's syndromes. Magnetic resonance imaging made a rapid and correct diagnosis. The patient received an emergent right hemilaminectomy from C2 to C6 with removal of hematoma and subsequently made a complete recovery.

Brown-Sequard Syndrome↗
PubMed1994

Repeat operations in failed microvascular decompression for trigeminal neuralgia.

For the study of pathogenesis and treatment of recurrent trigeminal neuralgia, we performed 31 repeat operations from among 400 patients with trigeminal neuralgia in the past 10 years. Initially, of these 400 patients, 376 underwent microvascular decompression only, and 24 underwent partial sensory rhizotomy with or without microvascular decompression. Fifty-three patients (14%) had recurrences after microvascular decompression, of which 31 patients underwent repeat operations. Among the repeat operations, there was negative exploration in 16 patients (52%), arterial loop compression in 7 (22%), venous compression in 4 (13%), and Teflon compression or adhesion in 4 (13%). Twenty-one patients had early recurrences within 1 year, and 10 patients had late recurrences. Negative exploration and arterial compression were more likely in early recurrence (P = 0.01). Continuing demyelination might occur in patients with negative exploration, even when adequate decompression had been initially performed. Seventy percent of the patients had no recurring pain by way of partial sensory rhizotomy for negative explorations, redecompression of arterial loops, division of offending veins, or lysis and reposition of Teflon. About half of the patients had positive findings that were amenable without rhizotomy in the repeat operations. A repeat operation for failed microvascular decompression is a good choice if the condition of the patient is tolerant.

Arteries↗
PubMed1992

[Analysis of the volatile organic acids in 5 kinds of pericarpium Trichosanthis].

The volatile organic acids in the pericarps of Trichosanthes kirilowii, T. rosthornii, T. truncata, T. hupehensis and T. cucumeroides (Cucurbitaceae) were analyzed by methylation, GC and GC-MS-DS. The results showed that they were composed of fifteen long-chain fatty acids, such as palmitic, linolenic, linoleic, lauric, myristic acid, etc.

Drugs, Chinese Herbal↗
PubMed1991

[Study on biomechanics of incisor movement retracted by Hawley labial wire of removable appliance].

The authors used the space three point location Approximation method and L-positioner instrument to study the biomechanics of incisor movement retracted by Hawley labial wire of removable appliance. The magnitude, direction and effective point of orthodontic force from the X-ray films and models were measured. More than 2800 data groups were collected. The results showed that; 1) the force of retracted Hawley wire acts on the incisors can be divided into incisal and lingual components, and there was a stable contact point on the incisors; 2) The Hawley wire was constructed by stainless wire of 0.7-0.8 mm in diameter (made in Shanghai Dental Material Factory), retracting it 1mm horizontally may produce 100-150 gm orthodontic force and 3) the direction of tooth movement is not the same direction of orthodontic force, and is affected by resistant force of the periodontal tissue.

Adolescent↗