Biomedical subjects

D Han

Publications and source records attributed to D Han.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Analysis and separation of chromium(III) oligomers by ion chromatography].

A method of analyzing chromium(III) oligomers in aqueous solution by means of TSK-Gel ion exchange analytical column and diode array detector was developed. The effects of determination conditions, elution and ionic strength on analysis were investigated carefully and the analytical condition was optimized. The samples were separated for 10 min by using TSK-Gel SP-5PW(75 mm x 7.5 mm i.d., 10 microns) as column, 3 mol/L NaClO4-0.03 mol/L HClO4 as mobile phase, and detected at the wavelength of 200 nm. The method was simple, rapid and repeatable. This method was also used to determine the concentration of each fraction under various conditions of preparing chromium(III) oligomers and rendering the optimized preparation parameters.

Chromatography, Ion Exchange↗

PubMed2001

[Studies on the chemical constituents from Tribulus terrestris].

AIM: To investigate the chemical constituents of the fruit of Tribulus terrestris J.. METHODS: Various chromatographic techniques were used to separate the chemical constituents. ESIMS, IR, 1HNMR, 13CNMR and HMBC were used to determine the structures of the isolated constituents. RESULTS: Two new compounds were isolated from the fruits of Tribulus terrestris J. and were identified as neohecogenin-3-O-beta-D-glucopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->4)-beta-D-galactopyranoside (I); neohecogenin-3-O-beta-D-glucopyranosyl (1-->4)-beta-D-galactopyranoside (II). CONCLUSION: Compounds I and II are new steroidal saponins.

Fruit↗

PubMed2001

Characteristic behavioral seizures and abnormal signal asymmetry of magnetic resonance imaging in an electrogenic rat model of chronic epilepsy.

Chronic tetani (60 Hz, 2 s, 0.4~0.6 mA) were administered to the dorsal hippocampus (DHPC) or the medial temporal lobe neocortex (MTNC) of rats, to study the role of the entorhinal cortex (EC)-hippocampal loop in temporal lobe epileptogenesis. This was repeated once a day for 7 or 10 days. Magnification of hyper-intensity was induced by tetanization of the HPC or the MTNC, as detected by contralateral T(2) weighed magnetic resonance imaging (T(2)-WI). The effects were associated with an enlarged volume of the lateral ventricle (LV), which was verified histologically. T(2)-WI hper-intensities, contralateral to the tetanized hemispheres, were observed with high frequency primary wet dog shakes (WEDS) in the DHPC-stimulated rats and with low frequency WEDS in the MTNC-stimulated rats. It seems likely that the same neural mechanisms are shared by chronic tetanization of the right HPC and the righ MTNC, involving the closed EC-HPC loop. Poor correlation between contralateral T(2)-WI hper-intensities and light primary behavioral seizures in the MTNC-stimulated rats might be attributed to a controlled information flow into or out of this loop because of potential EC gating. In addition, asymmetric T(2)-WI hyper-intensities in the LV area reflected a hemispheric dependence, contralateral to the electrogenic focus in our model of rat epilepsy.

Animals↗

PubMed2001

Possible role of dentate gyrus in greneration of rat temporal lobe epilepsy induced by electrical stimulation.

Possible role of the dentate gyrus (DG) and the hippocampus (HPC) in temporal lobe epileptogensis was investigated in an electrogenic model of rat epilepsy. Chronic tetani (60 Hz, 0.4-0.6 mA. 2 s) were administered once daily for 7 days to the right dorsal hippocampus (DHPC) or the right DG. Animal behavior was observed and depth electro-graphic seizures and T(2)-weighted magnetic resonance images (T(2)-WI) were measured. Results indicated that the frequency of primary wet dog shakes (WEDS) in the DG-stimulated rats was much lower than that in the DHPC-stimulated rats (P<0.05). The mean maximal wave-amplitude in DG electrographs was also much lower than that in HPC electrographs (P<0.05). The oscillations proportion of DHPC electrographs increased after DHPC-tetanization (from 2/9 up to 7/9 rats). T(2)-WI hyperintensity in the lateral ventricle area was detected only in the DHPC-tetanized rats, not in the DG-tetanized rats (P<0.05). These results suggest that the DG acts as a filtering site in the entorhinal cortex-HPC neuronal circuitry and its dysfunction causes damage to the HPC and the generation of temporal lobe epilepsy.

Animals↗

PubMed2001

[Polycystic ovaraian syndrome and hyperinsulinemia].

OBJECTIVE: To identify the relationship between polycystic ovarian syndrome and hyperinsulinemia. METHODS: Age, body height, body weight, serum estradiol, progesterone, testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), triiodothyronine (T3), tetraiodothyronine (T4), insulin, oral glucose tolerance test (OGTT), and cortisol were measured in 28 patients with polycystic ovarian syndrome (PCOS). RESULTS: Sxiteen patients (57.1% of total) had hyperinsulinemia. Among them one patient was found diabetic. No difference was noted in age, height, body weight, body mass index, serum estradiol, progesterone, testosterone, FSH, LH, PRL, T3, T4, cortisol, and glucose of OGTT between hyperinsulinemia and non-hyperinsulinemia patients. However the LH/FSH ratio (2.4 +/- 1.5) in hyperinsulinemia patients was significantly higher than 1.2 +/- 0.6 in non-hyperinsulinemia patients (P = 0.0125). In addition, the results showed that the fasting serum insulin, insulin after OGTT, the insulin/glucose ratio at 30, 120 minutes, 180 minutes, the area under curve of and the insulin, insulin resistant index (IRI) were higher in hyperinsulinemia pateints than in non-hyperinsulinemia patients respectively. Furthermore, the fasting insulin level, insulin/glucose ratio were found to be negatively related to insulin sensitivity index and positively related with beta-cell functioning index. CONCLUSION: Hyperinsulinemia and insulin resistance accompany with some of the PCOS patients in China. Further investigations will be necessary to clarify the relevant mechanisms.

Adult↗

PubMed2001

[Effects of acute infrasound exposure on vestibular and auditory functions and the ultrastructural changes of inner ear in the guinea pig].

OBJECTIVE: To define the effects of acute infrasound exposure on vestibular and auditory functions and the ultrastructural changes of inner ear in guinea pigs. METHODS: The animals involved in the study were exposed to 8 Hz infrasound at 135dB SPL for 90 minutes in a reverberant chamber. The sinusoidal pendular test (SPT), auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) were respectively detected pre-exposure and at 0(within 2 hrs), 2 and 5 day after exposure. The ultrastructures of the inner ear were observed by scanning electron microscopy. RESULTS: The slow-phase velocity and the frequency of the vestibular nystagmus elicited by sinusoidal pendular test (SPT) declined slightly following infrasound exposure, but the changes were not significant (P > 0.05). No differences in the ABR thresholds, the latencies and the interval peak latencies of I, III, V waves were found between the normal and the experimental groups, and among experimental groups. The amplitudes of DPOAE at any frequency declined remarkably in all experimental groups. The ultrastructures of the inner ear were damaged to different extent. CONCLUSION: Infrasound could transiently depress the excitability of the vestibular end-organs, decrease the function of OHC in the organ of Corti and cause damage to the inner ear of guinea pigs.

Animals↗

PubMed2001

[Anatomic characteristics of lingual artery and midline glossectomy].

OBJECTIVE: To investigate the relationship between anatomic characteristics of lingual artery and midline glossectomy, for the purpose of increasing operative safety. METHODS: (1) 16 extraoral dissections of the submandibular region were performed on 8 human cadavers and to observe the origin and distribution of lingual artery. (3) The lingual artery was divided into three segments, and the length and adjacent organs were observed and measured. RESULTS: The whole length of lingual artery was (92.88 +/- 13.53) mm; At points of foramen cecum of the tongue, 5 mm and 10 mm prior to foramen cecum, 10 mm behind foramen cecum, and at adjacent part between root of the tongue and epiglotic vallecula, the distances between lingual artery and midline of the tongue were separately measured. The distances were (11.00 +/- 4.95) mm, (8.56 +/- 3.51) mm, (7.78 +/- 3.15) mm, (13.00 +/- 3.28) mm, (15.22 +/- 3.11) mm. The distances between lingual artery and the surface of tongue were (21.4 +/- 5.59) mm, (22.11 +/- 6.74) mm, (22.56 +/- 7.81) mm, (16.56 +/- 5.57) mm, (2.56 +/- 0.73) mm respectively. CONCLUSION: During the midline glossectomy, the lingual artery is easier to be damaged at the position where the root of tongue adjoining epiglottic vallecala. The operation should be done within 10 mm below the surface, 7 mm lateral to the midline, to avoid the damage of lingual artery.

Arteries↗

PubMed2001

[Multiple factors analysis of intraoperative bleeding and recurrence of juvenile nasopharyngeal angiofibromas].

OBJECTIVE: To study the effect of surgical treatment of juvenile nasopharyngeal angiofibromas and the factors influencing intra-operative bleeding and recurrence. METHODS: Thirty-four patients with juvenile nasopharyngeal angiofibromas treated surgically in Chinese PLA General Hospital between 1986 and 1999 were studied retrospectively. The relationship between surgical treatment, intraoperative bleeding, recurrence and age, duration, staging, preoperative treatment, times of previous operation, operative approaches was statistically analyzed. RESULTS: The tumors were totally resected in 30 patients, and five patients(16.7%) recurred during a mean follow-up of 77 months. The mean recurrence time after operation was 3.2 months (1-6 months). The amount of intraoperative bleeding correlated well with the age, duration, staging, preoperative treatment, and surgical approaches (P < 0.05), but not with times of previous operation (P > 0.05). Recurrence was not correlated with the age, duration, preoperative treatment and surgical approaches (P > 0.05), but correlated with staging (P < 0.05). CONCLUSION: The factors significantly influencing the intraoperative bleeding were the age, duration and staging. Recurrence was correlated with the tumor stages, incomplete resection or the exceedingly malignant activity of the tumor. Radiotherapy, with a dose of 30Gy, is an adjuvant therapy for incompletely resected, or residual tumors.

Adolescent↗

PubMed2001

[Observation of nasal mucosal cilia ultrastructure of Kartagener's syndrome].

OBJECTIVE: To report the ultrastructure of nasal mucosal cilia of Kartagener's syndrome and the operative results of 2 cases. METHODS: Both two cases were underwent endoscopic sinus surgery. Transmission and scanning electron microscopic examinations of nasal mucosa for case 1 were performed. RESULTS: All 2 cases presented situs inversus, chronic paranasal sinusitis and bronchiectasis. The electron microscopic examination showed that the shape of nasal cilia and "9 + 2" structure were normal, but the lack of inner dynein arm of cilia and confused arrangement of central pair of microtubules were confirmed. The recurrent of nasal polyps after 1-year follow-up was observed in case 1. CONCLUSIONS: The disturbance of mucociliary clearance due to congenital ciliary structure defect might be the cause of chronic sinusitis and polyps, which might be one of reasons for poor prognosis after operation and we should pay more close attention.

Adolescent↗

PubMed2001

[Roles of CD43, CD20 and local IgE in the pathogenesis of nasal polyps].

OBJECTIVE: To estimate the roles of CD43, CD20 and total IgE in the pathogenesis of nasal polyps. METHOD: Twenty-six cases of nasal polyps and 20 cases of mucosa of middle turbinates were used in present study. RESULTS: The number of CD43+ cells, CD20+ cells and plasma cells in nasal polyps were significantly more than that in middle turbinates (P < 0.01). The positive rate of local IgE+ cells in nasal polyps was significantly higher than in middle turbinate (P < 0.01). CONCLUSION: There were active cellular immunity and humoral immunity in nasal polyps. Local allergy may play a role in the pathogenesis of nasal polyps.

Adolescent↗

PubMed2001

[Rat hearing loss and hearing organs mitochondrial DNA4834 deletions associated with hypercholesteremia].

OBJECTIVE: To determine whether or not the rat hypercholesteremia contributes to hearing organs mtDNA4834 deletion and involves in the development of hearing loss. METHODS: The rat hypercholesteremia model (n = 38) was established by feeding with high cholesterol diet and the control group (n = 22) with common diet for 6 months. The rats were tested for auditory sensitivity using auditory brainstem response (ABR). Twenty-one left cochleae and 27 left cochlear nuclei from experimental group and 10 left cochleae and 13 left cochlear nuclei from control group were harvested. The total DNA of them was extracted. mtDNA was amplified by nest PCR to examine the presence of mtDNA4834 deletion. RESULTS: Our result showed: (1) There is a significant increase in serum cholesterol level and ABR threshold in the experimental group. (2) The mitochondrially-encoded tRNA and ND1 segments were amplified from all samples, as well as mtDNA4834 deletions. (3) The incidence of mtDNA4834 deletions in hearing organs of hypercholesteremia rats was significantly higher than that of the control group (P < 0.05). CONCLUSION: Extended hypercholesteremia can induce hearing loss, and mtDNA4834 deletion in hearing organs may be one of the pathogenic mechanisms.

Animals↗

PubMed2001

[Study on vibration mode of different phonatory source and compensation after partial laryngectomy].

OBJECTIVE: To investigate the nature of pathological voice production and compensatory mechanism after partial laryngectomy. METHODS: Vocal function of 93 cases following partial laryngectomy (28 cases of horizontal partial laryngectomy, 35 vertical partial laryngectomy, 30 horizontal-vertical partial laryngectomy) were examined by acoustic analysis, aerodynamic analysis and videostroboscopic examination. RESULTS: Horizontal supraglottic laryngectomy(HL) resulted in slight dysphonia after operation. The cover of vocal fold was hypertrophic and edematous. Mucosa wave was increased. Acoustic analysis showed significant difference between normal and horizontal laryngectomy groups(P < 0.05). Vertical laryngectomy(VL) resulted in moderate-severe dysphonia. Acoustic analysis was significantly worse in VL than in normal group(P < 0.01). The nonglottic phonatory source was the contralateral ventricular fold or contralateral vestibular mucosa (arytenoid mucosa, root mucosa of glottis) to approximate the reconstructed flap. It was noted that contralateral vocal fold did not participate in vibration. Horizontal-vertical partial laryngectomy (HVL) resulted in moderate-severe dysphonia. Acoustic analysis of HVL was significantly worse than that of normal phonation(P < 0.01). The site of compensatory mucosa vibration upon phonation was the contralateral vocal fold or contralateral hypertrophic arytenoid mucosa. The thinner the flap, the better the vocal quality was. Vocal quality of VL was worse than that of HVL in regard to shimmer, jitter, normalized noise energy, maximal phonation time and harmonic-noise ratio, but there was no significant difference between them. CONCLUSIONS: Partial laryngectomy has different vibrating compensatory modes: Voice function of horizontal partial laryngectomy was the best as it preserved the normal vibration mode; vertical partial laryngectomy was the worst with the nonglottic vibrating source of reconstructed flap-ventricular fold. The reconstructed flap, ventricular fold, mucosa of epiglottis and arytenoid take predominantly part in neoglottal vibration. The situation, volume and pliability characteristic of reconstructed flap was also important to vocal quality.

Aged↗

PubMed2001

[Clinical study of juvenile-onset recurrent respiratory papillomatosis].

OBJECTIVE: To study the clinical behavior of juvenile-onset recurrent respiratory papillomatosis in order to find some factors correlated to the development of this disease, and to sum up the significance and experience of CO2 laser surgery. METHOD: Sixty patients with juvenile-onset recurrent respiratory papillomatosis from September 1995 to December 1998 were retrospectively analyzed. RESULTS: The age of onset in 50 cases (83.3%) was below 4 years, and the peak-age was 2 years. The rates of recurrence were 72.0% and 45.7% (chi 2 = 4.71, P < 0.05) below and over 2 years, respectively. The rates of aggressive disease were 88.0% and 54.3% (chi 2 = 7.66, P < 0.01) below and over 2 years, respectively. The predominant sites of the disease were the vocal cords, the false vocal cords, the laryngeal ventricle, the laryngeal surface of the epiglottis and the subglottic region. Tracheostomy induced the development of tracheal papilloma, therefore should be avoided as possible. Laryngeal papilloma might be divided into four types on the basis of the growth manner and surface form corresponding to clinical behaviors. Five patients were followed-up for 1.5 years without recurrence, 18 patients had fewer recurrences following treatment, 33 patients were under treatment, and 3 patients died. Nineteen patients lost follow-up. The major complications included laryngeal and tracheal stenosis. CONCLUSION: Clinical behaviors of juvenile-onset recurrent respiratory papillomatosis were relevant to the age, growth form and tracheotomy. CO2 laser was an ideal instrument for ablation of the laryngeal papillomas with the following advantages: simple management, less bleeding, preservation of laryngeal structure and avoidance of tracheostomy.

Age Factors↗

PubMed2001

[Expression of vascular endothelial growth factor and transforming growth factor-beta 1 in nasal polyps].

OBJECTIVE: To study the expression and significance of vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) and transforming growth factor-beta 1(TGF-beta 1) in nasal polyps. METHODS: Expression of VEGF/VPF and TGF-beta 1 in nasal polyps from 34 patients and middle turbinates from 30 patients with deviation of nasal septum was prospectively studied with immunohistochemistry. Tissue sections were observed under optical microscope. RESULTS: (1) The VEGF/VPF positivity in vascular endothelium and in glandular cell was significantly higher in nasal polyps than in middle turbinates (P < 0.01 and P < 0.05, respectively); (2) The TGF-beta 1 positivity in extracellular matrix and in cells in the stroma was significantly higher in nasal polyps than in middle turbinates(P < 0.005); (3) The distribution and shape of TGF-beta 1 expressing cells in nasal polyps were similar to that of eosinophil, their positivities were significantly correlative; (4) The positivity of VEGF/VPF and TGF-beta 1 did not correlate with clinical type in nasal polyps (P > 0.05). CONCLUSION: (1) The VEGF/VPF may play a key role in the formation of heavy edema of nasal polyps; (2) The TGF-beta 1 may contribute to some of the pathologic changes observed in nasal polyps, such as thickening of the epithelial basement membrane and stromal fibrosis; (3) Eosinophils in nasal polyps represent a major source of TGF-beta 1.

Adolescent↗

PubMed2001

[The effects of streptomycin on the calcium influx in SGCs during depolarization].

OBJECTIVE: To examine the effect of streptomycin on the calcium influx in spiral ganglion cells (SGCs) during depolarization and the differences among different concentrations of streptomycin and SGCs sources with the aim of exploring the mechanism of acute streptomycin ototoxicity. METHODS: The SGCs of guinea pig cochlea were isolated using an enzyme-machine method and loaded with 10 mumol/L Fluo-3/AM for 30 min at 37 degrees C. Dissociated SGCs loaded with Fluo-3 were examined with a confocal microscope (ACAS Ultima, USA) using a 20 x objective lens and linear scan mean. The fluorescent images collected every 5-sec for a total of 300 sec were stored in a computer. The fluorescent intensity of the images was analyzed by a software cooperated with the confocal microscope, and a curve of fluorescent intensity changes against time was obtained. RESULTS: The [Ca2+]i of SGCs was steady under the perfusion with standard extracellular solution. The [Ca2+]i of SGCs increased in 12/14 cells under the perfusion with 150 mmol/L high potassium solution, but increased in only 1/10 cells induced by the high potassium calcium free solution. After treating with 1 mmol/L, 0.1 mmol/L, 0.01 mmol/L streptomycin, the [Ca2+]i of the SGCs perfused with the potassium solution was increased in 0/9, 6/14, 7/13 cells, respectively. After the SGCs were treatment with 0.02 mmol/L streptomycin, the [Ca2+]i of the SGCs perfused with the high potassium solution was increased in 5/10 SGCs from the apical turn and in 0/15 SGCs from the basal turn. CONCLUSION: Perfusion with high potassium media can result in obviously increased [Ca2+]i of the SGCs, and the increase of the [Ca2+]i in the SGCs may originate from the extracellular calcium influx. The calcium influx can be blocked by streptomycin and such effects depend on streptomycin concentrations and SGCs sources.

Animals↗

PubMed2001

[Application of an image-guidance system in endoscopic sinus surgery].

OBJECTIVE: To evaluate the advantages of image-guidance system in endoscopic sinus surgery. METHODS: Twenty-eight endoscopic sinus surgery procedures were performed with the help of image-guidance system. There were 11 cases of chronic sinusitis with/or without nasal polyps, 4 juvenile nasopharyngeal angiofibromas, 6 pituitary adenomas, 3 ethmoid ossifying fibromas, 2 nasopharyngeal mixed tumors, 1 nasal leiomyoma, 1 fungal sinusitis, and 1 inverted papilloma. RESULTS: In all cases, the preoperative operation would take 15-30 minutes, the registration rate was 1.3-2.0, the localization accuracy was within 1 mm. Compared with the traditional endoscopic sinus surgery, the operative time did not differ obviously. No complication occurred. CONCLUSIONS: The image-guidance system could identify the operative borders and critical anatomical structures together with the corresponding CT data, especially in cases with anatomical variations, unidentified anatomical landmarks, and intranasal or anterior skull base tumors. Endoscopic sinus surgery, combined with the image-guidance system, provided accurate tumor resection while preserving normal tissue. It could increase surgical effectiveness and decrease overall surgical complications. We believe that the image-guidance system is a useful tool for endoscopic sinus surgery.

Adolescent↗

PubMed2001

[Effect of p14ARF gene on cell growth of human laryngeal tumor cells and expression of endogenous p53 protein].

OBJECTIVE: To explore the inhibitory effect of p14ARF on the cell growth of laryngeal carcinoma and the expression on endogenous p53. METHODS: p14ARF cDNA was transferred to the cell line Hep-2 of squamous cell carcinoma of the larynx by gene transfer to study the cell cycles and the expression of endogenous wild type p53 using flow cytometry, polymerase chain reaction(PCR) and Western-Blotting. RESULTS: Expression of p14ARF significantly affected the Hep-2 cell growth. The clone-forming efficiency of the Hep-2 cells transferred with p14ARF was 57%, compared with empty vector pcDNA3. The number of 48 hours after transfer with p14ARF cDNA at both G0/G1 and G2/M was two fold as the control. The expression of endogenous wild type p53 was significantly enhanced. CONCLUSION: Expression of p14ARF can up-regulate the expression of endogenous wild type p53 and inhibit the Hep-2 cell growth of human laryngeal squamous cell carcinoma at both G0/G1 and G2/M.

Carcinoma, Squamous Cell↗

PubMed2001

[Experimental study on polyaspartic acid inhibition of gentamicin-induced generation of reactive oxygen species in guinea pig cochlea].

OBJECTIVE: To observe the polyaspartic acid(PAA) inhibition of gentamicin-induced reactive oxygen species generation in cochlea of guinea pig and to investigate the protective mechanism of polyaspartic acid on gentamicin ototoxicity. METHODS: Eighty-eight guinea pigs were divided randomly into four groups (GM, PAA + GM, PAA, and Saline). Gentamicin-induced reactive oxygen species (ROS) formation in cochlear tissue was detected directly with electron paramagnetic resonance (EPR) spectrometry at 1st, 5th and 10th day after administration of the drugs. At the same time, ABRs of guinea pigs were recorded and ultrastructural changes of lysosomes in the cochlear hair cells were observed with transmission electron microscopy. RESULTS: 1. At 1st day after administration of PAA and GM, there was some increase in EPR spectrometry in group GM and PAA + GM, There was no significant difference of ABR thresholds and ultrastructural changes of lysosomes in the cochlear hair cells among four groups(P > 0.05). 2. At 5th day, there was significant increase in of EPR spectrometry in group I (37.74 +/- 4.10, P < 0.01). At 10th day after administration of PAA and GM, there was no significant difference in EPR spectrometry among four groups (P > 0.05). In GM group, ultrastructural changes of lysosomes beneath cuticular plate of cochlear hair cells were more significant at 10th day than those at 5th day, including the increased number and volume of lysosome. In group GM, the longer the gentamicin administrated, the more significant increase in ABR thresholds had been noted. CONCLUSION: PAA significantly inhibits gentamicin-induced reactive oxygen species generation in cochlea of guinea pig, which showed that PAA has protective effect on gentamicin-ototoxicity and -phospholipidosis in guinea pigs.

Animals↗