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Biomedical subjects

Y Fang

Publications and source records attributed to Y Fang.

At least 217 records · Page 12Linked to original sources
PubMed1995

[Adrenocorticotropic hormone (ACTH): antagonistic effect on opioid analgesia in central nervous system of the rat and its possible mechanisms of action].

Using the behavioral pharmacological approach, we have studied the influence of ACTH on the analgesia mediated by three types of opioid receptors (mu, delta, kappa). The mechanisms by which ACTH antagonizes opioid analgesia were explored at receptor level and post-receptor second messenger level. The expression of Fos protein induced by ACTH was also observed in rat brain. The main results show that ACTH selectively antagonizes spinal opioid analgesia mediated by mu and delta, but not kappa receptors. The proposed mechanisms of the anti-opioid effect of ACTH are that ACTH can modulate opioid-induced decrease of intracellular cAMP content and the suppression of calcium influx. ACTH has been shown to induce Fos protein expression in selected brain areas including the nuclei involved in pain modulation. These brain areas may serve as sites of action for ACTH to exert its anti-opioid effect.

Analgesics, Non-Narcotic↗
PubMed1995

[Study on treatment of absence of the oval window].

From March 1983 to June 1991 ten cases (twelve ears) underwent middle ear exploration for severe conductive hearing loss. Absence of oval window was found. Vestibulotomy and reconstruction of the ossicular chain were performed. Among patients with horizontal segments of the facial nerve displaced downward over the oval window region, or those after operation the inital gain of the hearing gradually reduced as a result of ablitecation of new fenestra, fenstration operation on the horizontal semicircular canal was performed. Vestibulotomy (10 ears) had resulted in elevated spech reception thresholds of 10-30 dB or more in 7 ears. Four of these patients had initial gain of the hearing reduced after 3 months. Fenestration in four cases resulted in elevated SRT of 20-45 dB. So fenestration is preferred. The authors have also presented their experience in the management of absence of the oval window.

Adolescent↗
PubMed1995

[Progress in the study of the central ACTH receptors].

In addition to pituitary gland, adrenocorticotropic hormone (ACTH) was also found to exist in the neurons of the central nervous system (CNS). ACTH-containing neurons project their fibers to the broad areas of CNS. ACTH-related peptides play many roles in CNS. In recent years, the study about the central ACTH receptors has been made a great progress. It has been realized that the binding sites of ACTH exist in extensive regions of CNS. In the four types of currently cloned ACTH receptors (melanocortin receptors), two of them (MC3R and MC4R) are prevalent in the CNS.

Animals↗
PubMed1995

[Scavenging effects of daphnetin and its Cu, Zn complexes on superoxide radical].

The scavenging effects of daphnetin (D) and its Cu, Zn complexes on superoxide radical (O2-.) generated through the photooxidation of riboflavin were studied with human red blood cells (RBC) and RBC membrane as experimental material. The Cu ( II ) complex showed the highest activity. SOD, D and its Cu ( II ), Zn ( II ) complexes were found to have inhibitory effect on the production of lipid peroxide in the membrane, SOD being the best among them.

Erythrocyte Membrane↗
PubMed1995

[Recurrent meningitis and spontaneous cerebrospinal fluid otorrhea].

Five children with recurrent meningitis were surgically confirmed to have vestibular fistula and spontaneous cerebrospinal fluid (CSF) otorrhea. The vestibular fistulas were successfully repaired under general anaesthesia. No complications were found after follow-up for 3-8 years. The etiology of CSF otorhinorrhea, location of fistulas, diagnosis and treatment of spontaneous vestibular CSF otorrhea were discussed.

Cerebrospinal Fluid Otorrhea↗
PubMed1995

[Scanning electron microscopic observation of human vestibular sensory epithelia].

Three-dimensional structures of human vestibular sensory epithelia were studied under scanning electron microscope. The saccular macula showed an "L" pattern and increased in thickness near the striola. The utricular macula appeared like an open shell. Flask and test-tube shaped hair cells were identified as type-I and type-II sensory cells respectively. Stereocilia were arranged in a step like progression; the kinocilium was near the longest stereocilium and looked more flexible than stereocilia. The tallest stereocilia and kinocilia faced away from the striola toward the periphery in the macula sacculi, and toward each other along the striola in the utricular maculae. Polarization directed to the utricle in the lateral crista, and away from the utricle in the anterior and posterior cristae. Otoconia varied in size and shaped like crystals with pyramidal ends.

Adolescent↗
PubMed1995

Atomic force microscopy study of fine structures of the entire surface of red blood cells.

Glutaraldehyde-fixed red blood cells were imaged by tapping mode atomic force microscopy (TMAFM) in air at room temperature. The results show that TMAFM can visualize the morphology of the red blood cell at both cellular and nanometer scales. The scan size covers the range from several hundred nanometers to more than one hundred micrometers. TMAFM not only has a higher resolution than the optical microscope, but also can observe biological samples without precoating as required for scanning electron microscopy (SEM). The AFM images of the entire surface of an uncoated red blood cell with nanometer resolution are successfully reconstructed by 28 AFM images of the preselected subareas on the surface of the red blood cell. These images reveal directly the fine structures of the external surface of uncoated red blood cells in air. The surface exhibits a characteristic structure composed of a large number of closely-packed nanometer particles with a size ranging from a few nanometers to tens of nanometers. These "particulate" components are evenly distributed, and no jumping protrusion or depression structures were found. These particles give rise to a very smooth surface of the red blood cell as shown in a large-scan AFM image. In addition, the 28 AFM images obtained by the continuous scanning over 3 hours indicate that TMAFM can image soft biological samples such as red blood cells stably and reproducibly.

Erythrocytes↗
PubMed1994

In vitro development of suramin-resistant clones of Trypanosoma evansi.

By exposure to gradually increasing concentrations of suramin in modified Baltz's cell free culture system, suramin-resistant clones of Trypanosoma evansi, JGcl-160, JX-lcl-160 and ZJcl-140, were derived from suramin-sensitive clones JGcl, JX-lcl and ZJcl, respectively, over a period of 550 days. In vitro tests showed that the IC50 values of JGcl-160, JX-lcl-160 and ZJcl-140 were 358.5, 412.3 and 246.4 micrograms/ml respectively, which were 1792.5, 1874.1 and 1760.0 times higher than those of their parent clones. The values for the curative dose CD100 for intact mice infected with JGcl-160, JX-lcl-160 and ZJcl-140 were 80, 120 and 30 mg/kg respectively, which were 5.3, 8.0 and 3.0 times higher than those of each parent clone. The CD100 values for immunosuppressed mice infected with these clones were 250, 300 and 100 mg/kg, respectively, which were 3.1, 2.5 and 3.3 times higher those for intact mice infected with the same clones.

Animals↗
PubMed1994

GTP-binding proteins: necessary components of the presynaptic terminal for synaptic transmission and its modulation.

Using synapses that form between somata of Helisoma neurons in cell culture, we have studied the presynaptic regulation of synaptic transmission. Guanosine 5'-triphosphate (GTP)-binding proteins play critical roles in regulating synaptic transmission. Injection of guanine nucleotide analogues has demonstrated that one or more GTP-binding protein is necessary for transmitter release. Heterotrimeric G proteins continuously regulate the amount of transmitter released at the synapse by modulating potassium and calcium channels, and by controlling the secretory response to calcium. Perturbations of the synapse using guanosine 5'-diphosphate (GDP) beta S, GTP gamma S, and rab effector domain peptides suggest that small GTP-binding proteins also play critical roles in the synapse. We discuss the possibility that rab3, or related proteins, are required for exocytosis, and by cooperating with other proteins maintain vesicles in a docked state in the synapse.

Animals↗
PubMed1994

Optimal batch size for estimation of the prevalence of a disease using combined samples.

Great attention has been given to the combined sample test for its high efficiency. Here a model of mathematical expectation for combined samples has been worked out and used for investigating the prevalence of HCV in serum from blood donors. It was shown that this model was valuable if the probability of a positive test, e.g. the prevalence, is less than 0.31.

Blood Donors↗
PubMed1994

Properties of the binding sites of [3H]9-methyl-7-bromoeudistomin D in bovine aortic smooth muscle microsomes.

[3H]9-Methyl-7-bromoeudistomin D ([3H]MBED), a powerful caffeine-like Ca2+ releaser, binds to the caffeine binding site of terminal cisternae of skeletal muscle sarcoplasmic reticulum and activates Ca(2+)-induced Ca2+ release. Properties of the binding site of [3H]MBED were investigated in aortic smooth muscle. The specific activity was higher in microsomes than in other fractions. [3H]MBED binding sites in smooth muscle microsomes were of a single class with a high affinity (KD 50nM), comparable with that in skeletal muscle sarcoplasmic reticulum. Caffeine competitively inhibited [3H]MBED binding, indicating MBED shares the same binding site with caffeine. Solubilization and fractionation of the microsomes gave two fractions of [3H]MBED binding activities. These results suggest that, in smooth muscle, there are multiple binding sites of [3H]MBED and caffeine, which might correspond to different pharmacological actions of caffeine on smooth muscle. Therefore, [3H]MBED, which binds to the different binding sites of caffeine, is useful as a probe for investigation of the actions of caffeine at the molecular level.

Animals↗
PubMed1994

[Histochemical study of dopamine on rat substantia nigra--ventral tegmental area during status epilepticus].

We studied the amount of dopamine on the substantia nigra-ventral tegmental area during status epilepticus of male Wistar rats induced by coriaria lactone with fluorescence histochemical technique and autoexposuremeter of microscope. The intensity of dopamine fluorescence in the climax epileptic seizure group (10 rats) and postepileptic seizure group (8 rats) decreased significantly as compared with the control (10 rats), but the intensity of dopamine fluorescence in the pre-eileptic seizure group (10 rats) was not significantly different from that of the control group. The result indicated that epileptic seizure induces a decrease of the inhibitory neurotransmitter-dopamine. Therefore dopamine plays an important role in regulating the epileptic seizures.

Animals↗
PubMed1994

Topical capsaicin treatment suppresses formalin-induced fos expression in rat spinal cord.

Capsaicin (Cap) is a pharmacological tool to inactivate nociceptive afferents. The present study was undertaken to investigate the effects of topical application of Cap to sciatic nerve on the formalin-induced expression of proto-oncogene proteins c-fos in the rat spinal cord using immunohistochemical display of fos-like protein. In rats subjected to formalin injection into the hind paw, numerous fos-like immunoreactivity (FLI) neurons were found in the spinal dorsal horn, with heavy labeling in laminae I-II and V-VI. Following pretreatment of Cap, formalin-induced FLI expression was significantly abolished. It was suggested that activation of Cap-sensitive unmyelinated nociceptive afferents following formalin injection was primarily responsible for the activation of c-fos gene. Our data also provided further evidence supporting that topical application was an effective way to block the transmission of noxious primary afferents.

Animals↗
PubMed1993

On the structure of calonyctin A, a plant growth regulator.

The plant growth regulator calonyctin A, isolated from the dried leaves of Calonyction aculeatum L. House (Yue-Guang-Hua), was separated into two pure components by high performance liquid chromatography. By use of mass spectrometry based on various ionization techniques, one- and two-dimensional NMR spectroscopy, IR spectrometry, and chemical methods the molecular structures of the two homologous glycosides were determined. Each molecule contains two hydroxy fatty acid residues and four 6-deoxyhexose units. The fatty acids are 3-hydroxy-2-methylbutanoic acid and 11-hydroxytetradecanoic acid or 11-hydroxyhexadecanoic acid. The 6-deoxyhexose residues (three of quinovose and one of rhamnose) comprise a tetrasaccharide having the following structure: [formula: see text] The long-chain hydroxy acid is linked glycosidically through its O-11 to Qui D and esterified to O-2 of Qui C, forming a macrocyclic lactone. The 3-hydroxy-2-methylbutanoic acid is ester-linked to O-3 of Qui C.

Carbohydrate Conformation↗
PubMed1993

Effects of copper coordinate complexes on the scavenging of reactive oxygen species.

Effects of a 20-membered macrocyclic bicopper complex and dioxotetramine copper complexes with linear or cyclic structure on the scavenging of ROS have been studied by ESR. The results indicated that all three copper coordinate complexes have SOD mimetic activity. The dioxotetramine copper complex with linear or cyclic structure did not have the scavenging effect on .OH produced by H2O2-Fe++ and 1O2 produced by the H2O2-NaOCl system, but the 20-membered macrocyclic bicopper complex was found to be capable of depressing the intensity of the ESR spectrum of the adduct formed from TMP and 1O2 as well as making the spectrum of DMPO-OH adduct splittings. This fact may suggest that there are interactions between the ROS and 20-membered macrocyclic ring in the SOD mimic.

Cells, Cultured↗
PubMed1993

Trypanosomiasis of domestic animals in China.

Trypanosomiasis caused by Trypanosoma evansi (surra) is a problem of great economic importance in livestock in China because it affects important working animals: buffaloes in the south and east, and horses and cattle in the north and west. In addition, buffaloes are an important source of meat and leather for the Chinese population. In the north and west, T. evansi is found mainly in camels, whereas in the east, the south and the southwest, it is primarily buffaloes, cattle and horses that are affected by this parasitic flagellate. Although trypanosomiasis is one of the most important parasitic diseases of domestic animals in China, little information on this disease has been published. In this article Zhao-Rong Lun, Yuang Fang, Chang-Ji Wang and Reto Brun evaluate trypanosomiasis of domestic animals in China and review epidemiological studies of the past 40 years.

Journal Article↗