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Biomedical subjects

W Lai

Publications and source records attributed to W Lai.

At least 37 records · Page 2Linked to original sources
PubMed2000

Suppression of cytokine production and cell adhesion molecule expression in human monocytic cell line THP-1 by Tripterygium wilfordii polysaccharide moiety.

Extracts of the vine-like plant Tripterygium wilfordii (TW) have been widely used in China as an immunosuppressant and anti-inflammatory drug for the treatments of rheumatoid arthritis, lupus erythematosus and other inflammatory disorders. In this study the molecular mechanisms of action of three TW extracts (ethanol, aqueous, polysaccharide) on the expression of inflammatory cytokines and adhesion molecules were investigated by RT-PCR and immunofluorescence binding techniques. The lipopolysaccharide (LPS)-mediated stimulatory effects of tumor necrosis factor-alpha (TNF-alpha) cytokine production and cell adhesion molecule (CD11c, CD18, CD14, CD54) expression in human monocytic THP-1 cells were modulated by treatments of the TW extracts or tacrolimus (FK506). The TW polysaccharide moiety exhibited more profound immunosuppressive properties than the aqueous and ethanol extracts. Biochemical characterization of the polysaccharide moiety revealed a major molecular weight of 22 kDa (viz. PSP22). The PSP22 was found to be a potential immunosuppressant that manifests the necessary immunomodulating properties.

CD18 Antigens↗
PubMed2000

Estrogen receptors and the activity of nitric oxide synthase in the artery of female rats receiving hormone replacement therapy.

OBJECTIVE: To observe the expression of estrogen receptor and the activity of NOS in the arteries of female rats receiving estrogen replacement therapy. METHODS: Seventy-two female rats were randomly divided into four groups: group A: sham-ovariectomy; group B: ovariectomy; group C: ovariectomy with estrogen replacement therapy (benzoate estradiol, 5 microg i.m. once in 2 days); group D: ovariectomy with estrogen and progesterone replacement therapy (benzoate estradiol, 5 microg i.m. once in 2 days and progesterone, 1 mg i.m. once in 2 days). The rats were killed after 2 months. The receptor-binding assay was adopted to measure the estrogen receptors in the arteries of the rats, and the activity of NOS in the arteries was assessed by the hemoglobin reductase method. RESULTS: The ER number and NOS activity in the arteries of the ovariectomized group are less than those in sham-ovariectomy group (p<0.05). The ER number and NOS activity in the arteries of groups C and D are larger and higher than those in the ovariectomized group (p<0.05). No significant differences in the ER number and NOS activity were observed between groups C and D. CONCLUSION: The ER number and NOS activity in the rat artery significantly decrease after ovariectomy, while hormone replacement therapy can significantly increase the artery NOS activity and retain the ER number in the artery of the ovariectomized rats to normal level. The result may contribute to explaining the beneficial effect of estrogen in the prevention of coronary artery diseases in postmenopausal women.

Animals↗
PubMed2000

CYP11B2 expression in rat liver and the effect of spironolactone on hepatic fibrogenesis.

OBJECTIVE: In consideration of the hypothetical possibility that locally produced aldosterone is likely to take an active part in fibrogenesis of the liver, we undertook the present study to investigate the expression of aldosterone synthase gene CYP11B2 in rat liver and the curative effect of spironolactone on fibrosis of the liver. METHODS AND MATERIALS: 160 Wistar rats weighing about 250 g were divided into four groups as follows: model group, spironolactone group, malotilate group and control group. After 2, 4, 6, 8 and 10 weeks, the animals were sacrificed. Morphological examination was based on microscopic and electron microscopic findings. The area of collagen was examined by an Image Analyse System (Leica). By means of reverse transcriptase-polymerase chain reaction and in situ hybridization, the expression of CYP11B2 was detected. RESULTS: The expression of CYP11B2 mRNA, which was localized in the endoplasm of fat-storing cells, was upregulated when fibrogenesis occurred. The grade of fibrosis and the area of collagen in the spironolactone group were less than those in the model group before the 6th week (p < 0.05). After the 6th week, there was no significant difference between the spironolactone group and the model group (p > 0.05). CONCLUSIONS: The expression of CYP11B2 mRNA is upregulated in fibrotic liver. Spironolactone can partly have a fibrogenesis-inhibiting effect in the early stage of CCl(4)-induced hepatic fibrogenesis.

Animals↗
PubMed1999

Effects of cholic acid on blood pressure and production of vascular aldosterone and corticosterone.

The aims of this study were to search for the role of cholic acid in the regulation blood pressure of humans and rats and to investigate the effects of cholic acid on the production of vascular aldosterone and corticosterone in rats. Levels of serum total bile acids were measured by an enzymic spectrophotometeric method in normal controls, patients with essential hypertension, and in Wistar and spontaneously hypertensive rats. Levels in essential hypertension (7.3+/-3.4 micromol/l, n = 88) were higher than those of normal subjects (4.9+/-3.3 micromol/l, n = 86), and levels in SHR (13.9+/-3.8 micromol/l, n = 11) were slightly increased, but not significantly different from Wistar rats (10.4+/-5.1 micromol/l, n = 12). Male Wistar rats received cholic acid 80 mg/kg/day, orally, for 30 days, and blood pressure was monitored by a pressure transducer. Systolic blood pressure increased in Wistar rats treated with cholic acid compared to control rats. Mesenteric artery perfusion ex vivo was performed, and pressor responses to norepinephrine were determined in Wistar rats. The pressor responses to norepinephrine in mesenteric arteries treated with cholic acid were significantly increased. The perfusate from the mesenteric arteries was collected and applied to a Sep-Pak C 18 cartridge column for reverse phase high performance liquid chromatography, and levels of both aldosterone and corticosterone were determined by radioimmunoassay. Levels of aldosterone were decreased but those of corticosterone increased in the perfusate from arteries treated with cholic acid. Reverse transcriptase polymerase chain reaction showed that cholic acid inhibited the expression of 11beta-HSD2 and CYP11B2 mRNA in mesenteric arteries. These results reveal that cholic acid is able to induce hypertension and provide evidence that cholic acid inhibits the transcription of both 11beta-HSD2 and CYP11B2 in vasculature, leading to lower aldosterone and higher corticosterone production in vessels and increased vasoconstrictor responses to norepinephrine.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1999

Effects of glycyrrhizin on production of vascular aldosterone and corticosterone.

This study is to confirm the role of glycyrrhizin on blood pressure and to test the effects of glycyrrhizin on production of vascular aldosterone and corticosterone in rats. Male Wistar rats received glycyrrhizin (Sigma) 200 mg/kg/day p.o. for 5 weeks, and blood pressure was monitored by a pressure transducer. Systolic blood pressure significantly increased in Wistar rats treated with glycyrrhizin compared to that without glycyrrhizin. Mesenteric artery perfusion ex vivo and pressor responses to norepinephrine were performed. The pressor responses to norepinephrine in mesenteric arteries treated with glycyrrhizin were significantly increased. The perfusate from the mesenteric arteries was collected and applied to a Sep-Pak C 18 cartridge column, used for reverse-phase high-performance liquid chromatography, and measured for both aldosterone and corticosterone by radioimmunoassay. Levels of aldosterone were decreased but those of corticosterone increased in perfusate from arteries treated with glycyrrhizin. RT-PCR showed that glycyrrhizin inhibited the expression of 11beta- HSD2 and CYP11B2 mRNA in mesenteric arteries. These results confirm that glycyrrhizin is able to induce hypertension, and provide evidence that it inhibits the transcriptions of both 11beta-HSD2 and CYP11B2 in the vasculature, leading to lower aldosterone and higher corticosterone production in vessels, and increased vasoconstrictor responses to norepinephrine.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1999

[The study of growth hormone on wound healing rate in adult burns].

OBJECTIVE: To determine the effects of rhGH on wound healing in adult burn patients. METHODS: 42 patients with burn wounds covering over 83% of total body surface area were enrolled in this placebo controlled prospective study. They were comparable in nutrient intake, TBSA, and full thickness burn area. For rhGH group patients rhGH subcutaneously was given in the dose of 0.2 U.kg-1 at 8 a.m. each morning for 14 days. The control group patients were given normal saline as placebo. Protein catabolism, immunocompetence, healing time of burn wounds and donor sites were assayed. RESULTS: 1. The patients in rhGH group had higher serum levels in albumin, transferrin, prealbumin and CD4 T-cells (P < 0.01). 2. The healing time of autologous skin grafting and donor site and the length of hospital stay were significantly shorter in rhGH group patients compared with control group. CONCLUSION: rhGH could enhance the wound healing rate, improve protein anabolism and reduce the length of hospital stay in severe burn patients.

Adolescent↗
PubMed1999

Aldosterone biosynthesis in extraadrenal tissues.

OBJECTIVE: To determine whether extraadrenal tissues synthesize aldosterone in addition to vascular tissue and brain. METHODS: Ex vivo kidney perfusion was performed in normal Wistar rats, ACEI pretreated and adrenalectomized rats prior to the perfusion experiment. After equilibration for 30 minutes, 120 ml of perfusate was collected and subjected to reverse-phase HPLC and then aldosterone was measured by RIA. By RT-PCR and Southern blot the expression of aldosterone synthase gene-CYP11B2 mRNA was studied in both kidney tissue and cultured renal tubular epithelial cell, lung and liver tissues. In situ hybridization was used to identify the cell types of liver and lung expressing CYP11B2 mRNA. RESULTS: Production of aldosterone in the kidney perfusate was not changed in adrenalectomized rats although it was decreased in the group pretreated with ACEI perindopril. By RT-PCR and Southern blot the expression of CYP11B2 mRNA was demonstrated in both kidney tissue and cultured renal tubular epithelial cell. We have also identified CYP11B2 mRNA expression in liver and lung of rats. In situ hybridization showed that CYP11B2 mRNA was localized in the endoplasm of liver fat-storing cell (Ito cells) and type II alveolar cells of lung. CONCLUSIONS: These studies prove that kidney, liver and lung are able to produce aldosterone.

Aldosterone↗
PubMed1999

The role and significance of Luo Zhiyuan's Shu yi hui bian in the history of plague in Lingnan (south of the five ridges).

Being the earliest monograph on plague in China, Luo Zhiyuan's Shu yi hui bian, not included in the National Catalogue of TCM Books, include the following contents: personal idea on the etiology of plague; Luo's friend Wu Xuanchang' unpublished Shu yu zhi fa on the treatment and manifestations of plague; Luo's specific recipe for plague based on medified Wang Qingren's Jie du huo xue decoction based on Wang Qingrens yi lin gai cuo; therapy for critical cases; many therapies applied on Lingnan, including experimental recipes, external therapy, preventive methods, and preventing recurrence methods; Luo's special administrating methods, including persisting day-and-night method, immediate persisting method, single-dose persisting method, and double-dose persisting method. He also gave several cured case records. His book, featuring unique idea with good effect, was repeatedly printed and extensively distributed, exerting influence, more or less, on the plague monographs of later ages, and occupying important position in the history of plague on Lingnan and the whole country as well. His idea of "that poisons and static blood" in pathogenesis and therapeutic principle of antitoxicity and activating blood is coincided with the results of present day clinical and laboratory studies. His administration of medicines is heuristic to the therapy of critical cases with Chinese medicaments and to the recognition of pathogenesis, etiology, and treatment of modern plague as well as other diseases of similar etiology and pathognesis and is worth of further study.

China↗
PubMed1999

[Research on the plague epidemic in Guangzhou (Canton) in 1894].

Early in the end of the 1870s, there were signs of local epidemic that occurred in the region of the end of Pearl River valley, most probably spread from the Beihai epidemic region through sea route. A severe epidemic of plague occurred in 1894 under the unusal dry and warm weather. However, the weather had nothing to do with the epidemic after the outbreak of the epidemic. Reports on the victims inside the city were focused in April to July, especially in May, first appeared in the regions inhabited by Muslin and Manchu centered in the whole area of western city and southern old city, where cases showed a tendency to distribute along the circular river around the city. The manifestations included swollen nodules, fever, chilliness, and coma. The death toll numbered to 0.1 million. TCM treatment includes cooling, dispersing, detoxification and blood activation, as well as acupuncture and rubbing with cold water, etc.

China↗
PubMed1999

[Effects of glycyrrhizin on blood pressure and its mechanisms].

OBJECTIVE: To confirm the action of glycyrrhizin on blood pressure by inhibiting the activity of 11beta-hydroxysteroid dehydrogenase type II (11betaHSD 2) and to test its mechanism. METHODS: Male Wistar rats and SHRs (weighing 150 - 220 g) were given glycyrrhizin (Sigma) 200 mg/kg/day, orally for 5 weeks and 3 months. The blood pressure was monitored by means of a pressure transducer connected to a polygraph and recorded. Histological pathological changes of the nutrient arteries of the heart and aorta were studied with light microscope. Mesenteric artery perfusion ex vivo and pressor responses to norepinephrine were performed. The perfusate from the mesenteric arteries was collected and used for reverse phase high performance liquid chromatography to measure aldosterone and corticosterone level. RT-PCR was used to measure the expression of 11betaHSD 2 and aldosterone synthase (CYP11B2) mRNA. RESULTS: The results showed that the systolic blood pressure was significantly increased in Wistar rats treated with glycyrrhizin compared with those not treated. Hyperplasia of smooth muscle cells and hypertrophy in arterioles were observed under microscope. The pressor responses to norepinephrine in mesenteric arteries treated with glycyrrhizin were significantly increased. The level of aldosterone was decreased but that of corticosterone was increased in perfusate treated with glycyrrhizin. RT-PCR showed that glycyrrhizin inhibited the expression of 11beta-HSD2and CYP11B2 mRNA in aorta. CONCLUSION: These results confirm that glycyrrhizin is able to induce hypertension. There is evidence that it inhibits the enzymes of both 11beta-HSD2 and CYP11B2 in vasculature and leads to higher corticosterone and lower aldosterone production in vessels as well as an increase in vascular responses to norepinephrine.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1999

[The effect of combined treatment of recombinant human growth hormone and insulin-like growth factor-1 on wound healing and protein catabolism in burned rats].

OBJECTIVE: To investigate the effect of combined treatment of recombinant human growth hormone (rhGH) and insulin-like growth factor-1 (IGF-1) on wound healing and protein catabolism in burned rats. METHODS: Forty Wistar rats with deep II degree scald injury were divided randomly into four groups and received rhGH (0.1 U/kg.d), rhGH (0.1 U/kg.d) plus IGF-1 (2.0 mg/kg.d), IGF-1 (2.0 mg/kg.d) and Ringer's solution (2 ml/kg.d, as control group) respectively. The wound healing time and protein catabolism levels of every groups were compared after 2 weeks. RESULTS: Total body weight began to increase after 2 weeks in rhGH group and rhGH plus IGF-1 group, but in control group, it was occurred after 4-5 weeks. The body weight of rhGH plus IGF-1 group was 1.65 times than that of rhGH group. The wound healing time in rhGH plus IGF-1 group (17.1 +/- 4.4) days was significantly lower than that of rhGH (20.5 +/- 4.8) days and control group (29.7 +/- 6.3) days. The protein level of rhGH plus IGF-1 group was significantly higher than that of control group and rhGH group. CONCLUSION: It suggests that rhGH plus IGF-1 with synergism is more effective in promoting wound healing and increasing the protein catabolism.

Animals↗
PubMed1999

[An eight-factor analysis of early skeletal Class II malocclusion using Fränkel appliance].

OBJECTIVE: To investigate the change of eight-factor after Fränkel appliance treatment in skeletal class II malocclusions. METHODS: X-ray cephalometric film. RESULTS: Fränkel appliance can be used to enhance the growth of ramus (Factor 2) and body (Factor 1) of the mandible, decrease the angle of cranial base (Factor 8) and made the maxilla rotate (Factor 4) anteriorly, which were benefit to the treatment of class II malocclusion. However, neither the vertical (Factor 5) and sagittal (Factor 3) growth of maxilla nor the height of posterior alveolar bone (Factor 6) can be inhibited by use of Fränkel appliance. CONCLUSION: Fränkel appliance is suitable to the treatment of class II patients with deficient mandible and almost normal maxilla, while Fränkel appliance would rather not be used for patients with overgrown maxilla or vertical growth pattern.

Adolescent↗
PubMed1998

PTR3, a novel gene mediating amino acid-inducible regulation of peptide transport in Saccharomyces cerevisiae.

We have isolated and characterized the Saccharomyces cerevisiae PTR3 gene by functional complementation of a mutant deficient for amino acid-inducible peptide transport. PTR3 is predicted to encode a protein of 678 amino acids that exhibits no similarity to any other protein in the database. Deletion of the PTR3 open reading frame pleiotropically reduced the sensitivity to toxic peptides and amino acid analogues. Initial rates of radiolabelled dipeptide uptake demonstrated that elimination of PTR3 resulted in the loss of amino acid-induced levels of peptide transport. PTR3 was required for amino acid-induced expression of PTR2, the gene encoding the dipeptide/tripeptide transport protein, but was not necessary for nitrogen catabolite repression of peptide import or PTR2 expression. It was determined that PTR3 also modulates expression of BAP2, the gene encoding the branched-amino acid permease. Furthermore, we present genetic evidence that suggests that PTR3 functions within a novel regulatory pathway that facilitates amino acid induction of the PTR system.

Amino Acid Transport Systems↗
PubMed1998

Recipient to donor conduction of atrial tachycardia following orthotopic heart transplantation.

We report a case of atrial tachycardia in a 60-year-old male 8 years postorthotopic heart transplantation. At electrophysiology study, the clinical rhythm was found to arise from the remnant of the recipient atrium and was successfully terminated by delivery of radiofrequency energy. Surgical scars formed at the anastomosis of the recipient and donor atrium during the time of orthotopic heart transplantation are thought to electrically isolate the two areas. Although rarely recognized, dysrhythmias originating from the recipient atrial remnant may occur more often than previously thought.

Catheter Ablation↗
PubMed1998

Aldosterone overproduction and CYP11B2 mRNA overexpression in vessels of spontaneously hypertensive rats.

Aldosterone is synthesized in extra-adrenal tissues such as blood vessels and brain. Damage to blood vessels could play a crucial role in perpetuating hypertension. In this study, we determined both aldosterone production and aldosterone synthase gene-CYP11B2 mRNA expression in vessels of spontaneously hypertensive rats (SHR). The results showed that aldosterone was overproduced in the vasculature of SHR, by means of ex vivo mesenteric artery perfusion, HPLC, and RIA, and that CYP11B2 mRNA expression was upregulated in aortas of SHR, confirmed by RT-PCR and Southern blot.

Aldosterone↗
PubMed1998

[The treatment and rehabilitation of high-voltage electric burns].

High-voltage electric burns is refractory with high rate of amputation (46%) in early stage and unfavorable functional recovery in later stage. Little breakthrough has so far been made in this respect. From Jan. 1985 to Jan. 1996, ninety-six cases with high-voltage burns were treated in our department. Seventy-one cases of various tissue flap grafting were applied to treat early electric burns, among which sixty-four cases were successful. The amputation rate was reduced to 30%. Postoperatively, a long-term rehabilitation training at home was carried out. Most of them achieved a good appearance of the wounded sites and limbs and satisfactory ability to work or self-care. It was suggested that early thorough debridement of necrosis tissue, careful reservation of living tissue, appropriate choice of tissue flap and postoperative rehabilitation training were of great importance to achieve a good prognosis.

Adolescent↗
PubMed1996

[Experimental research on the distribution of insulin in condyle during mandibular functional protrusion in growing rats].

The purpose of this study is to evaluate insulin change in condylar cartilage during functional advancement of rat mandible by immunohistochemical technique (ABC method) in order to provide further information about the role of insulin in orthopedics and the relationship between insulin and proliferation of condylar cartilage. Staining gradient of insulin is observed in condylar cartilage, with the stain deepest in the geriminal layer, medial in the transitional, least in the maturational layer. The posterior region of condylar cartilage in the experimental groups is shown to have thickened significantly as compared with the control groups, especially the germinal layer. Stained-positive cells exhibit deeper stain and higher percentage. The stain in the other layers is also more obvious than that in the control groups. The results suggest: Insulin level in condyle changes with the different cartilage layers. Insulin distribution appears higher when condylar chondrocytes proliferate rapidly and lower when they differentiate actively. Functional orthopedics may stimulate the growth of condylar cartilage and raise the insulin level. The demonstrates that insulin correlates with hyperplasia of conylar chondrocytes.

Animals↗