Biomedical subjects

B Luo

Publications and source records attributed to B Luo.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Clinical observation of phacoemulsification with foldable intraocular lens implantation through a limbus incision].

OBJECTIVE: To investigate the clinical therapeutic effects of phaco-emulsification with foldable intraocular lens implantation through a limbus tunnel incision. METHODS: Eighty-six patients (107 eyes) with senile cataract underwent phacoemulsification with acrylic foldable posterior chamber intraocular lens implantation through a 4 mm superior limbus tunnel incision. RESULTS: The corrected visual acuity of 0.5 or better was 62.6% at the 1st day, and 76.6%, 92.5% and 88.8% respectively at the 1st week, 1st month and 3rd month postoperatively. CONCLUSION: Phacoemulsification with foldable intraocular lens implantation through a limbus tunnel incision has advantages of both scleral tunnel incision and clear corneal tunnel incision. The postoperative therapeutic effects are satisfactory.

Adult↗

PubMed2001

[The pathology and DNA quantitative study of renal clear cell carcinoma in children].

OBJECTIVE: To investigate the pathological features of renal clear cell carcinoma (RCCC) in children and its relationship to the DNA content of cancer cells and DNA ploidy. METHODS: The pathologic morphology of 4 cases of RCCC in children were observed. Using image analysis instruments the quantity of tumor cell DNA was measured. RESULTS: The cytoplasm of the tumor cells were clear in all four cases. Papillary structures were present in these tumors, of which the papillary structure in two cases was over 50%, three cases had small calcified bodies with prominent bleeding and necrosis. Around tumor the glomerular and tubular of kidney always is normal the average DNA index was 1.31. They presented diploidy, high diploidy or subtetraploidy. CONCLUSIONS: The specific features of most RCCC in children are clear cytoplasm, most contain papillary structures, calcified bodies, often with bleeding and necrosis. Around tumor the glomerular and tubular of kidney is always normal. The DNA contents of cancer cells present diploidy, high diploidy or subtetraploidy.

Carcinoma, Renal Cell↗

PubMed2001

[Detection of HPV16 E6 gene in cervical tissues by quantitative polymerase chain reaction].

OBJECTIVE: To study the relationship between the quantities of HPV16 E6 gene in cervical tissues and the course of cervical disease. METHODS: The number of copies of HPV16 E6 gene was detected by competitive PCR in 44 positive samples including 20 cases of chronic cervicitis, 6 cases of cervical dysplasia and 18 cases of cervical cancer. RESULTS: The mean copies of HPV16 E6 gene in chronic cervicitis, cervical dysplasia and cervical cancer were 6.16, 5.33, and 6.45 copies in each microgram of cervical tissue respectively. The quantities of HPV16 E6 gene were not significantly different between cervical dysplasia and chronic cervicitis (P<0.01). CONCLUSIONS: This study underscores the importance of the relationship between the quantities of HPV16 E6 gene and the course of cervical disease. It also suggests that quantification of HPV16 E6 gene may be useful as a prognostic tool to identify women who are at increased risk of developing cervical cancer.

Female↗

PubMed2000

Water activity as the determinant for homogeneous ice nucleation in aqueous solutions

The unique properties of water in the supercooled (metastable) state are not fully understood. In particular, the effects of solutes and mechanical pressure on the kinetics of the liquid-to-solid phase transition of supercooled water and aqueous solutions to ice have remained unresolved. Here we show from experimental data that the homogeneous nucleation of ice from supercooled aqueous solutions is independent of the nature of the solute, but depends only on the water activity of the solution--that is, the ratio between the water vapour pressures of the solution and of pure water under the same conditions. In addition, we show that the presence of solutes and the application of pressure have a very similar effect on ice nucleation. We present a thermodynamic theory for homogeneous ice nucleation, which expresses the nucleation rate coefficient as a function of water activity and pressure. Recent observations from clouds containing ice are in good agreement with our theory and our results should help to overcome one of the main weaknesses of numerical models of the atmosphere, the formulation of cloud processes.

Journal Article↗

PubMed2000

Syntheses and structures of quinuclidine-stabilized amido- and azidogallanes.

Quinuclidine-stabilized amido- and azidogallanes, HGa[N(TMS)2]2(quin) (1), H2Ga[N(TMS)2](quin) (2), HGa-[N(H)(2,6-iPr2C6H3)]2(quin) (3), and H2GaN3(quin) (4), were synthesized from the quinuclidine adducts of mono- and dichlorogallane. Structural determinations revealed that all compounds were monomeric with four-coordinate gallium centers. Reactions of the five-coordinate compound, HGaCl2(quin)2, with 2 equiv of Li[N(TMS)2] or Li[N(H)(2,6-iPr2C6H3)] resulted in the isolation of compound 1 or 3. A ligand redistribution during the reaction of H2GaCl(quin) with Li[N(H)(2,6-iPr2C6H3)] produced compound 3 and H3Ga(quin) in a 1:1 molar ratio.

Journal Article↗

PubMed2000

Inhibition of pulmonary eosinophilia and airway hyperresponsiveness in allergic mice by rolipram: involvement of endogenously released corticosterone and catecholamines.

This study investigates the role of adrenal-derived catecholamines and corticosterone on the inhibition by rolipram, a phosphodiesterase (PDE)-4 inhibitor, of pulmonary eosinophilia and airway hyperresponsiveness (AHR) in allergic mice. The following experimental groups were studied in mice sensitized and challenged with ovalbumin (OVA): normal, adrenalectomized, propranolol (beta-adrenoceptor antagonist) and metyrapone (corticosterone synthesis inhibitor) treated. These interventions were studied both in the absence and in the presence of rolipram. Eosinophil numbers in the bronchoalveolar lavage (BAL) and AHR to methacholine were measured 24 h after OVA challenge. Treatment of sensitized mice with rolipram (0.3 - 10 mg kg(-1), p.o.), inhibited pulmonary eosinophilia and the AHR to methacholine in OVA-challenged mice. Adrenalectomy increased the number of eosinophils in the BAL of OVA-challenged mice but had no effect on AHR to methacholine. Adrenalectomy attenuated both the rolipram-induced inhibition of BAL eosinophilia and AHR to methacholine in OVA challenged mice. Propranolol (10 mg kg(-1), p.o.) had no effect on the inhibition of eosinophilia by rolipram but attenuated the inhibition of AHR to methacholine in OVA challenged mice. On the other hand, metyrapone (10 mg kg(-1), p.o.) attenuated the inhibition of eosinophilia by rolipram but had no effect on the inhibition of AHR to methacholine in OVA challenged mice. Metyrapone-treatment alone increased the number of eosinophils in the BAL of OVA-challenged mice. These results identify an important role for adrenal-derived catecholamines and corticosterone on the inhibition of pulmonary eosinophilia and AHR by rolipram in allergic mice.

Animals↗

PubMed2000

[Epidemiological feature on diabetes mellitus among permanent inhabitant in the Special Economic Zone of Shenzhen].

OBJECTIVE: To investigate prevalence and relevant factors of diabetes mellitus among permanent inhabitant in Shenzhen. METHODS: The prevalence of 8 200 inhabitants aged over 20 in Shenzhen was studied. Blood glucose was determined by glucose - oxidase method. RESULTS: According to the WHO diagnostic standard, the prevalence rates of DM and IGT were 4.23% and 11.94% respectively. The prevalence increased apparently with age. The history of clan and overweight were related to the prevalence rates of DM and IGT. The people of DM and IGT were mostly accompanied with high levels of triglyceride, total cholesterol, uric acid, creatinine and low level of high dense lipoprotein (HDL). CONCLUSION: The history of clan, old age, overweight and higher fattiness were found risk factors of DM and IGT.

Adult↗

PubMed2000

[Risk factors of type 2 diabetes in Shenzhen].

OBJECTIVE: The study was designed to investigate the risk factors of Type 2 diabetes in the new city Shenzhen. METHODS: A representative sample of 8,182 adults aged over 20 to 75 years old were randomly selected in the residents of Shenzhen, China in 1997. Type 2 diabetes was diagnosed according to the WHO criteria. Questionnaire survey, anthropometric measurement and blood analysis were carried out, and logistic regression analysis was used to study the risk factors. RESULTS: The results showed that the prevalence of type 2 diabetes in subjects with high total cholesterol were 4.9 times of those with lower TC value. Subjects with high triglyceride had a prevalence 5.7 times of those who had lower TG. Those HDL-ch had a prevalence 68.7% higher than those with normal HDL-ch value; on the other hand, those HDL-ch > 1.91 mmol/L were 44.6% lower in the prevalence than those with normal HDL-ch. The prevalence of type 2 diabetes in subjects with BMI >or= 25 were 2.6 times of those with BMI < 25. Subject with hypertension (>or= 140/90 mm Hg) had a prevalence 3.8 times of those with normal blood pressure. Subjects with family history of type II diabetes had a prevalence 2.0 times of no family history, and women who had delivered babies over 4 kg had a prevalence 1.9 times of those who had babies less than 4 kg. Subjects with waist/hip ratio (WHR) >or= 1.0 had a prevalence 5.1 times of those with WHR < 1.0. The prevalence of type 2 Diabetes was higher with increasing amount of cigarette smoking and the duration (in years) of smoking or increasing drinking (alcohol) and the duration (in years) of drinking. CONCLUSIONS: The blood glucose level was found to be positively correlated with TC or TG, and negatively correlated with HDL-ch. This study demonstrated again that TC, TG, HDL-ch, obesity, hypertension, family history of type 2 diabetes and in women, delivery of babies over 4 kg and age were risk factors of type 2 diabetes.

Adult↗

PubMed2000

[Expression of ET of early ischemic myocardium in rats].

To study the expression of ET of early ischemic myocardium, we designed a model of early myocardial ischemia (EMI) in rats. The study was conducted with SABC method and HE staining. Cardiac myocytes of ischemia showed a little ET-positive at 60-min. Cardiac myocytes, endothelium and smooth muscle of vessel showed ET-positive staining in the area of EMI after 120-min. Staining was negative for Ischemia myocardium at 30-min and for the control group. No change was seen with HE staining in all groups. The data indicates that ET-SABC method may reveal the injury of myocardial ischemia 60-min and longer and may provide a new marker to diagnose EMI in forensic pathology.

Animals↗

PubMed1999

Age-related variation in the interstitial tissues of the cardiac conduction system; and autopsy study of 230 Han Chinese.

The amount of fatty and fibrous tissues in 230 Han Chinese who died of noncardio-vascular diseases has been studied by a semi-quantitative method and analysed by chi-square test. The results have shown some consistency. Generally, in the sino-atrial node (SAN), fibrosis and fatty influtratin appear only after 40 years of age and increase one grade with every 20 years. The atrio-ventricular node (AVN) showed fatty change after 30 years of age and fibrosis appeared after 60. In the His bundle (HB), fatty infiltration and fibrosis appear after 40 years. The left bundle branch (LBB) showed similar changes. The appearance of fibrosis in the AVN seems to be later than that reported by Lev.

Adolescent↗

PubMed1999

Endothelin-1 stimulation of endothelial nitric oxide synthase in the pathogenesis of hepatopulmonary syndrome.

Biliary cirrhosis in the rat triggers intrapulmonary vasodilatation and gas exchange abnormalities that characterize the hepatopulmonary syndrome. This vasodilatation correlates with increased levels of pulmonary microcirculatory endothelial nitric oxide synthase (eNOS) and hepatic and plasma endothelin-1 (ET-1). Prehepatic portal hypertension induced by portal vein ligation (PVL) does not cause similar changes, suggesting that ET-1 in cirrhosis may modulate pulmonary eNOS and vascular tone. We assessed whether ET-1 altered eNOS expression and nitric oxide production in bovine pulmonary artery endothelial cells (BPAECs) and if a 2-wk low-level intravenous ET-1 infusion in PVL animals modulated pulmonary eNOS levels, microcirculatory tone, and gas exchange. ET-1 caused a 2.5-fold increase in eNOS protein in BPAECs, inhibitable with an endothelin B receptor antagonist, and an increase in eNOS mRNA and nitrite production. ET-1 infusion in PVL animals caused increased pulmonary eNOS levels, intrapulmonary vasodilatation, and gas exchange abnormalities without increasing pulmonary arterial pressure. ET-1 produced during hepatic injury may contribute to the hepatopulmonary syndrome by modulating eNOS and inducing pulmonary microcicrulatory vasodilatation.

Animals↗

PubMed1999

[A study of p53 gene mutations in squamous cell carcinoma in eyes].

OBJECTIVE: To inquire into the molecular biological mechanisms of the occurrence of squamous cell carcinoma in eyes. METHODS: Using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, we detected 63 samples taken from 63 cases (including 36 invasive squamous carcinoma, 7 carcinoma in situ, 20 papillomas) for 248 point mutations in p53 gene. RESULTS: 22.2% (8/36) squamous cell carcinomas, 14.3% (1/7) carcinomas in situ were shown to contain the point mutation in codon 248 of p53 gene exon 7 and no point mutation was found in papillomas, the difference being significant (P = 0.021). No point mutation was in patients over 70, while in patients younger than 70, the mutation rate was 33.3%, the difference being significant (P = 0.24). No significant correlation was found between p53 gene mutations and clinical pathological manifestations (P > 0.05). CONCLUSIONS: p53 gene mutations play roles in the early stage of the development of squamous cell carcinomas, and there is no correlation between p53 gene mutations and clinical manifestations. The mutation in p53 gene is not the main cause of neoplasms in the elder persons after the seventh decade of life.

Adolescent↗

PubMed1999

[The analysis of pathological changes of cardiac conduction system in 54 cases of cardiac sudden deaths].

OBJECTIVE: To elucidate the exact cause of death in cases of cardiac sudden deaths. METHODS: Sampling of cardiac conduction system (CCS) designed by the research group was adopted. The CCS of 120 cases died of cardiac sudden deaths were collected for routine histological examination. RESULTS: In 54 out of 120 cases, the causes of death were attributed to lesions present in the CCS, and 85.2% of them were young adults. The peak age range was from 20 - 30. Much more in males (6.7:1). The pathological changes in CCS include: inflammation (46.2%), fatty infiltration, hypertrophic cardiomyopathy associated with CCS changes; hemorrhage, developmental anomalies, fibrosis and tumors. CONCLUSION: The pathological changes of CCS are relatively common, as the cause of sudden deaths. Which is considered to be the pathological basis of the unstable cardiac electric potentials and arrhythmia. This study recommended the necessity of routine examination on CCS in cases of sudden deaths.

Adult↗

PubMed1999

[Immunohistochemical study on myocardial acute ischemia reperfusion injury in rats with anti-FOS protein antibody].

To investigate law of FOS protein induced by myocardial ischemia reperfusion (MI/R) in acute period, a model in 20 anaethetized SD rats was established. Rats with normal and ischemia were used as control groups. Specimens were studied immunohistochemically with c-fos antibody. After ischemia 20 minutes, followed by 30 minutes reperfusion, the area of MI/R showed nuclei of myocytes positive staining in cryosection slides. In C2 group, the area showed nuclei of myocytes (37.76% +/- 9.66%) positive staining weakly. In C3 group, nuclei of cardiac myocytes(40.34% +/- 3.32%) was significantly positive. In C4 group it began to attenuate(35.36% +/- 4.81%). The myocardium in normal and ischemic control groups showed negative staining. No changes were seen with HE staining. Our data indicated that immunohistochemical method may reveal acute MI/R injury of ischemia 20 min and reperfusion 30 min with anti-FOS protein staining and there is problely a peak between 60-120 min after reperfusion. It is possible that the method be used to diagnose sudden cardiac death in forensic medicine.

Animals↗

PubMed1999

[The development of a RF electrical pole catheter for heart ablation].

This article describes a RF electrical pole catheter for heart ablation. There is a device in the catheter, that can adjust the bending of the catheter tip on which there are a pair of electrical poles that is able to record and map the electrical potential of the heart, and to transfer 50 W electrical energy for focus ablution of heart disease.

Cardiac Surgical Procedures↗

PubMed1998

Cholecystokinin B receptors in the periaqueductal gray potentiate defensive rage behavior elicited from the medial hypothalamus of the cat.

Defensive rage behavior is mediated over a descending pathway from the medial hypothalamus to the dorsolateral midbrain periaqueductal gray (PAG) where further integration of this response takes place. The present study sought to determine the roles of CCK-A and CCK-B receptor activation in the PAG in modulating defensive rage behavior. The 'hissing' component of the defensive rage response was used throughout the experiment as the measure of defensive rage behavior. The basic design of the experiment involved placement of monopolar electrodes into the medial hypothalamus from which defensive rage could be elicited and cannula electrodes into the dorsal PAG for purposes of identifying defensive rage sites in this region and for microinjections of CCK compounds into these sites at a later time. Microinjections of the selective CCK-B receptor antagonist, LY288513 (1.05, 4.2, 17.0 nmol/0.25 microliter), into the PAG suppressed the hissing response in a dose- and time-dependent manner. Microinjections of the CCK-B agonist, pentagastrin, (0.5 and 1.0 nmol/0.25 microliter) facilitated the occurrence of defensive rage behavior. Moreover, administration of LY288513 (17 nmol/0.25 microliter) 55 min prior to pentagastrin (1.0 nmol/0.25 microliter) delivery blocked the facilitatory effects of pentagastrin. Administration of the CCK-A antagonist, PD140548 (34 nmol/0.25 microliter), into the PAG failed to alter response latencies for defensive rage behavior. In contrast, microinjections of the CCK-B antagonist, LY288513 (4.2, 17.0 nmol/0.25 microliter), facilitated the occurrence of predatory attack behavior elicited from the lateral hypothalamus. This finding demonstrates the specificity of the effects of CCK-B receptor blockade upon hissing. A combination of immunocytochemical and retrograde tracing procedures using microinjections of Fluoro-Gold (8%, 6 microliters) into the PAG were employed to identify the possible loci of CCK neurons that project to the PAG. The data revealed that neurons labeled for both CCK and Fluoro-Gold were located in the dorsolateral aspect of the midbrain tegmentum, identifying this region as a source of CCK inputs to the PAG. Overall, the findings demonstrate that CCK-B receptors in the PAG potentiate defensive rage behavior and likely suppress predatory attack.

Animals↗

PubMed1998

Endothelin-1 in the rat bile duct ligation model of hepatopulmonary syndrome: correlation with pulmonary dysfunction.

BACKGROUND/AIMS: Models of hepatopulmonary syndrome require both hepatic injury and portal hypertension to develop pulmonary microvascular and gas exchange abnormalities. Recently, increased endothelin-1 levels associated with vasodilatation, have been observed in cirrhosis. We investigated endothelin-1 production in common bile duct ligated animals with hepatopulmonary syndrome in comparison to partial portal vein ligated animals that do not develop hepatopulmonary syndrome. METHODS: Organ and plasma endothelin-1 were measured in sham, bile duct ligated and portal vein ligated rats, and Northern analysis and immunohistochemistry were performed in liver. Plasma endothelin-1 levels were correlated with pulmonary endothelial nitric oxide synthase levels and alveolar-arterial oxygen gradients. RESULTS: Hepatic and plasma endothelin-1 increased only after bile duct ligation, and were accompanied by increased hepatic endothelin-1 mRNA and increased endothelin-1 protein in biliary epithelium. Plasma endothelin-1 levels correlated directly with both pulmonary endothelial nitric oxide synthase levels and alveolar-arterial gradients. CONCLUSIONS: Enhanced hepatic production and increased plasma levels of endothelin-1 occur after bile duct ligation, but not after portal vein ligation, and correlate with associated molecular and gas exchange alterations in the lung. Endothelin-1 may contribute to the pathogenesis of hepatopulmonary syndrome.

Animals↗

PubMed1998

Garlic prevents hypoxic pulmonary hypertension in rats.

Hypoxic pulmonary vasoconstriction underlies the development of high-altitude pulmonary edema. Anecdotal observations suggest a beneficial effect of garlic in preventing high-altitude symptoms. To determine whether garlic influences pulmonary vasoconstriction, we assessed the effect of garlic on pulmonary pressures in rats subjected to alveolar hypoxia and on vasoconstriction in isolated pulmonary arterial rings. Garlic gavage (100 mg/kg body wt) for 5 days resulted in complete inhibition of acute hypoxic pulmonary vasoconstriction compared with the control group. No difference in mean arterial pressure or heart rate response to hypoxia was seen between the groups. Garlic solution resulted in a significant dose-dependent vasorelaxation in both endothelium-intact and mechanically endothelium-disrupted pulmonary arterial rings. The administration of NG-nitro-L-arginine methyl ester (a nitric oxide synthase inhibitor) inhibited the vasodilatory effect of garlic by 80%. These studies document that garlic blocks hypoxic pulmonary hypertension in vivo and demonstrate a combination of endothelium-dependent and -independent mechanisms for the effect in pulmonary arterial rings.

Acetylcholine↗