Biomedical subjects

L Guo

Publications and source records attributed to L Guo.

At least 109 records · Page 6Linked to original sources

PubMed2001

Induction of apoptosis by superoxide anion and the protective effects of selenium and Vitamin E.

OBJECTIVE: The purpose of this study is to investigate the effect of superoxide anion on the apoptosis of cultured fibroblasts and the protective role of selenium and Vitamin E. METHODS: Cultured fibroblasts (NIH3T3), with or without selenium or vitamin E in the medium, were treated by superoxide anion produced by xanthine/xanthine oxidase reaction system and changes in cell structure and DNA were observed microscopically and electrophoretically. RESULTS: Apoptosis was observed when superoxide anion at a concentration of 5 nmol/L or 10 nmol/L had acted on the fibroblasts for 5-10 h. Selenium and Vitamin E in the medium inhibited the apoptosis significantly when their concentrations reached 1.15 mol/L and 2.3 mol/L respectively. CONCLUSION: Selenium and vitamin E have protective effect against the apoptosis induced by superoxide anion. The effect of selenium is more remarkable than that of vitamin E.

Antioxidants↗

PubMed2001

[Studies on the relationship between clinicopathological features and human papillomavirus types in female lower genital tract carcinoma].

OBJECTIVE: To investigate the relationship between clinicopathological features and human papillomavirus types in female lower genital tract carcinoma. METHODS: Clinicopathological features of 100 cases of female lower genital tract carcinoma (63 cervical carcinoma and 37 vulvar carcinoma) were studied retrospectively. Standard PCR (HPV type 6/11, 16, 18) was applied to formalin fixed, paraffin embedded sections. RESULTS: There were 54 cases of cervical carcinoma and 33 cases of vulvar carcinoma in the 87 cases of target DNA qualified samples. The HPV detection rate in cervical carcinoma was 83.3%. HPV16 (55.6%) and HPV 18(24.4%) were the predominant types. In vulvar carcinoma, HPVs, mainly HPV 16(70%, 7/10), were detected in basaloid (83.3%, 5/6) and warty carcinoma (83.3%, 5/6), but none in conventional type of keratinized squamous cell carcinoma (0.0%, 0/21). Three of the 6 women with basaloid carcinoma were associated with cervical squamous neoplasia, and the same HPV type was found in both lesions in 2 of the 3 patients with two primary tumors. Four patients with basaloid carcinoma recurred after simple vulvectomy or local excision, but no lymph node metastasis occurred and all were still alive at last follow-up, with a median follow-up of 6.3 years. In contrast, the majority of the women with keratinized squamous cell carcinoma were over 65 years of age, with histologic extensive keratinization and poorer prognosis. CONCLUSIONS: A high detection rate of HPV 16 and 18 was found in cervical carcinoma. However, the sensitivity of HPV in vulvar carcinoma seems to be more related to histologic type.

Adult↗

PubMed2001

[Effect of methylmercury chloride on the c-fos expression in brain nerve cells of the rats].

OBJECTIVE: In order to study the mechanism of injury in the brain development caused by methylmercury chloride (MMC) and its effects on the c-fos expression in brain nerve cells of the rats with experiments in vitro and in vivo. METHODS: In vitro, the effect of MMC on c-fos expression in the cultured nerve cells was observed by immunocytochemistry(SP method). In vivo, Wistar pregnant rats were administered 4 mg MMC per kg of body weight by a gastric tube from the 7th to the 10th gastational days. On the 1st, 3rd, 5th, 7th, 10th and 15th days after birth, the rats were killed and tissue sections were prepared from their brain, respectively. The expression of c-fos was detected by SP method. RESULTS: The percentage of c-Fos-positive neuron in rats brain began to increase at 0.5 hours after being cultured in in vitro with 0.3 mumol/L MMC continuously, and increased gradually as length of the exposure to MMC prolonged. The percentage of c-Fos-positive of cultured nerve cells in vitro were (6.97 +/- 2.86)%, (66.86 +/- 5.32)% and (64.49 +/- 3.09)% in the experimental groups exposed to MMC for 10 min, 2 h and 6 h, respectively. In vivo, the percentage of Fos-positive neuron nuclei decreased with development of neonatal rats. The percentage of c-Fos-positive neuron in the experimental groups was higher than that in the control groups and decreased with length of development. The percentages of c-Fos-positive neuron were (47.01 +/- 3.79)% and (46.71 +/- 1.96)% in the experimental group 1 and 3 d, and (35.8 +/- 3.04)% and (33.35 +/- 1.06)% in the control group, respectively, with very significant difference. CONCLUSIONS: It is concluded that MMC could induce c-fos over-expression in the nerve cells of the rat brain, which could explain the mechanism of injury to brain development caused by MMC.

Animals↗

PubMed2001

[A study on the treatment of secondary glaucoma due to intumescent senile cataract].

OBJECTIVE: To discuss surgical methods of treating secondary glaucoma due to intumescent senile cataract. METHODS: Of 47 inpatient cases (49 eyes) who suffered from secondary glaucoma due to intumescent senile cataract, 28 cases (30 eyes) had been performed the following four different types of operation; (1) extracapsular cataract extraction (ECCE) and posterior chamber intraocular lens (PC-IOL) implantation with peripheral iridectomy, (2) ECCE and PC-IOL implantation with segmental iridectomy, (3) ECCE and PC-IOL implantation with trabeculectomy, and (4) five-combined-operation including scleral trephination, cyclodialysis, vitreous paracentesis, ECCE and PC-IOL implantation. RESULTS: The corrected visual acuities in 28 eyes had improved, whereas that in 2 eyes did not improve because of optic nerve atrophy. All the intraocular pressure in 30 eyes was within normal limit, including 12 eyes topically using antiglaucoma drugs. CONCLUSION: Most of patients with secondary glaucoma due to intumescent senile cataract can be cured surgically by iridectomy or trabeculectomy combined with ECCE and PC-IOL implantation. The five-combined-operation is an effective way to treat difficult cases such as long-term disease course, result with antiglaucoma drugs not satisfactory and swelling lens with flat anterior chamber.

Age Factors↗

PubMed2001

[Penetrance of Leber hereditary optic neuropathy in Chinese individuals with mitochondrial DNA 11778 mutation].

OBJECTIVE: To analyze the penetrance of Leber hereditary optic neuropathy (LHON) in families with homoplasmic mitochondrial DNA (mtDNA) 11778 mutation. METHODS: Maternal relatives of 16 families were analyzed based on ocular phenotype and primary mtDNA mutation analysis. RESULTS: One hundred and thirty individuals from the 16 families harbored the 11778 mutation. Of the 130 individuals, 65 were male and 65 female. Forty-three individuals (34 male and 9 female) were affected with LHON. The penetrance of LHON in the 16 families ranged from 13.3% to 66.7%, with an average penetrance of 33.1%. Males, with an average penetrance of 52.3%, were more affected than females who had an average penetrance of 13.8%. About 79% of the affected individuals were male with a male to female ratio of 3.8: 1. The number of affected females found in the families analysis is greater than that in the probands analysis where only 3 of 41 probands with LHON and mtDNA11778 mutation were female(male to female ratio =12.7:1). CONCLUSION: The penetrance of LHON in Chinese individuals with homoplasmic mtDNA11778 mutation is about one third,which is within the range of that in Caucasion.

DNA Mutational Analysis↗

PubMed2001

[Effect of fibrinogen on corrosion behavior of stainless steel in artificial blood solution].

The effect of fibrinogen on corrosion behavior of SUS316L and SUS317L stainless steel in artificial blood PBS solution has been investigated with electrochemical technology. The results showed that the corrosion potential (Ec) of stainless steel shifted negatively, the passivated current (ip) became less and the pitting corrosion potential (Eb) shifted negatively with the existence of fibrinogen in PBS. These indicate that samples become more sensitive to corrosion under this circumstance. SEM pictures demonstrated that stainless steel adsorbed fibrinogen on its surface.

Adsorption↗

PubMed2001

How are age and payors related to avoidable hospitalization conditions?

OBJECTIVE: (1) Examine variations in AHC indicators across age groups and payor types; (2) evaluate the impact of individual and community characteristics on AHC indicators; and (3) investigate the effect of adjustment for age and other factors on AHC indicators. MCOs can use AHC hospitalization and inpatient days to develop focused strategies in reducing AHC hospitalization. But biased comparisons often occur without adjustment for confounding factors. This study demonstrates that age and age/gender adjustments are needed for privately insured and Medicare patients while additional adjustment for community characteristics is needed for Medicaid and Self-Pay patients.

Adolescent↗

PubMed2001

Effects of recombinant human growth hormone (r-hGH) on experimental osteoporotic fracture healing.

OBJECTIVE: To observe the effect of recombinant human growth hormone (r-hGH) on osteoporotic fracture healing in rats, and to provide an effective therapy for osteoporotic fracture. METHODS: Thirty-six female 8-month-old SD rats were randomized into two groups: therapy group and control group. After the experimental model of osteoporotic fracture was established, the therapy group was treated with r-hGH of 2.7 mg/kg body weigh/day (1 mg=3 IU) for 10 days continuously by daily subcutaneous injection; whereas the control group was treated with equivalent saline. Plasma insulin-like growth factor I concentration was detected and bone mineral density (BMD) as well as biomechanical strength of callus were measured at 2, 4, 8 weeks. RESULTS: Plasma insulin-like growth factor I concentration in the therapy group was higher than that in the control group (P<0.005) at 2nd week and began to decline at 4th week. At 8th week, there was no significant difference between the two groups. At 4th week, callus area and BMD in therapy group were higher than those in the control group, but at 8th week, they were lower and BMD had a significant difference between the two groups (P<0.001). Biomechanical testing of callus showed that torsional strength of the therapy group was higher than that of the control group at 4th or 8th week, meanwhile maximum torsional angle had a significant difference between the two groups (P<0.005). CONCLUSIONS: The results show that exogenous r-hGH can stimulate osteoporotic fracture healing in rats.

Animals↗

PubMed2001

[Hypotony following vitreoretinal surgery].

OBJECTIVE: To evaluate the incidence and risk factors of hypotony in patients who have undergone vitrectomy for complex retinal detachment. METHODS: The medical records of 142 patients with complex retinal detachments who underwent vitrectomy were reviewed. Hypotony was defined as a persistent intraocular pressure (IOP) of 5 mmHg or less for 6 months in the follow-up. RESULTS: Among this 142 patients, hypotony occurred in 16 (11.3%) in 1 year postoperatively. The rate of hypotony in the patients with traumatic retinal detachment was 18.9%, and 6.7% in the patients with rhegmatogenous retinal detachment, the difference being statistically significant (chi(2) = 4.89, P < 0.05). The rate of hypotony in aphakia was 20.9%, and 7.0% for phakia, the difference being statistically significant (chi(2) = 5.67, P < 0.05). The rate of hypotony in the patients with proliferative vitreoretinopathy (PVR)-C class was l.8%, and l5.1% in the patients with PVR-D class, the difference being statistically significant (chi(2) = 3.97, P < 0.05). The rate of post-operative hypotony in the patients with preoperative hypotony was 21.9%, and. 6.9% in the patients without preoperative hypotony, the difference being statistically significant (chi(2) = 5.16, P < 0.05). CONCLUSIONS: Intraocular hypotony is a complication of vitrectomy for complex retinal detachment. The risk factors for the post-operative hypotony include trauma, aphakia, preoperative hypotony and severe PVR.

Adolescent↗

PubMed2001

[Primary research about reconstruction of cornea in three-dimensional collagen gel in vitro].

OBJECTIVE: To research the reconstruction of cornea in three-dimensional culture. METHODS: Using primary cultured corneal epithelial cells, stromal cells and endothelial cells rebuilt a corneal structure in three-dimensional collagen gel reconstruction system. The artificial corneal transparency was examined by a slit-lamp microscope. The biological characters of cells were tested by routine pathologic and transmission electron microscopic technology. RESULTS: The reconstructed corneal tissue formed three layers. The epithelial cell layer was two or three cell thickness. The endothelial cells formed a single layer. The stromal cells were diffuse in distribution in the collagen gel. The cells had proliferative ability and capability of producing collagen. CONCLUSION: The regular and transparent corneal structure can be rebuilt by tissue engineering technology.

Cells, Cultured↗

PubMed2001

[Detection of methylation status of p16 tumor suppressor gene in soft tissue leiomyosarcoma].

OBJECTIVE: To observe the methylation status of p16 tumor suppressor gene in human soft tissue leiomyosarcoma (LMS) and its relationship with p16 protein expression. METHODS: Methylation-specific PCR (MSP) assay was used to analyze the methylation status of 5' CpG island promoter/exon I region of p16 tumor suppressor gene in 38 LMS, 10 leiomyomas and 5 normal smooth muscle tissues. p16 expression in these tissues were examined by immunohistochemical assay. RESULTS: Hypermethylation of p16 was observed in 23.7% (9/38) of cases, of which 7 with negative pl6 staining and 2 with faint positive staining. In the cases without protein expression, hypermethylation rate of p16 was 50% (7/14). CONCLUSIONS: Epigenetic change due to 5' CpG methylation is the main cause of inactivation of p16 (INK4) gene which may be involved in tumor pathogenesis.

CpG Islands↗

PubMed2001

[The malignant potential of ovarian atypical endometriosis].

OBJECTIVE: To investigate the malignant potential of ovarian atypical endometriosis and ovarian endometrioid adenocarcinoma. METHODS: 12 cases of ovarian endometroid adenocarcinoma with associated endometriosis were reviewed retrospectively. Microsatellite markers were used to detect the loss of heterozygosity on chromosome 10q23 in ovarian carcinoma and their coexisting endometriosis. RESULTS: Among the 12 cases, benign eosinophilic metaplasia was observed in 8 cases, 5 of which (41.7%) with atypia. In these 5 cases, a spectrum of benign-atypical endometriosis with a transition to endometrioid adenocarcinoma was identified, and common genetic lesions were also detected in 2 of the 5 atypical endometriosis and their coexisting carcinomas. CONCLUSION: Histological observations as well as the molecular genetic evidence indicate that ovarian atypical endometriosis may possess a precancerous potential or play a role in the pathogenesis of certain malignant ovarian cancers.

Adenocarcinoma↗

PubMed2001

[Studies of intercellular communication in human rhabdomyosarcoma cell lines of different metastatic potential].

OBJECTIVE: To investigate the relationship between intercellular communication and three human rhabdomyosarcoma (RMS) cell lines of different metastatic potential. METHODS: Indirect immunofluorescent staining and laser scanning confocal microscope (ISCM) were used to detect connexin 43 (CX43), a molecule related with gap junctional intercellular communication (GJIC). Fluorescence redistribution after photobleaching (FRAP) was used to detect function of GJIC. RESULTS: A high level of CX43 protein expression was revealed in normal human myoblasts. CX43 protein was mainly localized on the surface of cells and sometimes in cytoplasm. CX43 expression was decreased in RMS cells. Both the detection rates and fluorescent intensity of CX43 decreased when the metastatic potential of RMS increased (P < 0.05). In contrast to normal, the fluorescence recovery rates of the RMS cells decreased and there was a negative correlation between the function of GJIC and malignancy of RMS cell lines (P < 0.05). CONCLUSION: Varying degrees of GJIC inhibition may correlate with different metastatic potential of RMS. This may help to determine the malignant behavior of RMS and be used as a prognostic index of RMS.

Animals↗

PubMed2001

[Clinical analysis of 17 cases rhabdomyosarcoma in ear nose and throat].

OBJECTIVE: To better understand the rhabdomyosarcoma in ear nose and throat and make correct diagnosis. METHOD: 17 patients with rhabdomyosarcoma in ear nose and throat were investigated. Diagnosis, treatment and prognosis were analyzed retrospectively. RESULT: Among 17 patients with rhabdomyosarcoma, three patients were in stage I, four patients were in stage II, eight patients were in stage III and two patients were in stage IV. It is the commonest in nose and predisposed to male. The clinic presentations were related to the size and location of tumor. Comprehensive therapy was need in most of patients. Poor prognosis was noted in this disease. CONCLUSION: This disease is easy to misdiagnose. Early diagnosis and comprehensive therapy will make contribution to better prognosis.

Adolescent↗

PubMed2001

[Diol column as stationary phase for high performance liquid chromatographic analysis of carbohydrates in drinks with evaporative light scattering detection].

A high performance liquid chromatographic method with a diol column and evaporative light scattering detector (ELSD) was established for the direct analysis of fructose, glucose, sucrose, maltose and raffinose in mixture. A separation column (Lichrospher 100 Diol, 250 mm x 4.0 mm i.d., 5 microns, Hewlett-Packard, USA) and a guard column (Zorbax Rx-SIL, 12.5 mm x 4.6 mm i.d., 5 microns) were used. The mobile phase was a mixture of dichloromethane-methanol (3.2:1, volume ratio). Regression equations revealed linear relationship (correlation coefficients: 0.995-0.999) between the mass of carbohydrates injected and the peak area of carbohydrates detected by ELSD. The detection limits of ELSD (S/N = 3) were about 0.20 microgram for all carbohydrates. This system could be used for the routine analysis of simple carbohydrates in some common drinks on market.

Beverages↗

PubMed2001

Change of visual acuity and related factors in idiopathic optic neuritis.

PURPOSE: To study the change of visual acuity and related factors in idiopathic optic neuritis. METHODS: Retrospectively studying 136 cases (210 eyes) of idiopathic optic neuritis hospitalized in our department during last 5 years. The data was analyzed with the methods of multivariate stepwise regression analysis by SPSS statistic package. RESULTS: The final visual acuity was very strongly related positively to the initial visual acuity at the time point of starting treatment and negatively to the time span beginning the treatment to the time showing improvement, age of patient and the duration from onset of the disorder to the time point of treatment beginning. CONCLUSIONS: Promptly right treatment can significantly change the natural course and the final vision of optic neuritis. Severe visual loss, old age, longer time without right therapy and slow improvement after the treatment may indicate an unfavorable final visual recovery. The different dosages of steroid applied in this study was not significant in view of the final visual acuity.

Adolescent↗

PubMed2001

[Spontaneous otoacoustic emissions and efferent control of cochlea].

OBJECTIVE: To study the relationship between spontaneous otoacoustic emissions(SOAE) and efferent control of cochlea and their clinical significance. METHODS: SOAE, transient evoked otoacoustic emissions (TEOAE), distortion product otoacoustic emissions (DPOAE) and contralateral white noise (60 dB SPL) suppression of TEOAE and DPOAE experiments were conducted in 312 ears of 95 patients with retrocochlear impairment and/or MOCS dysfunction and 64 normal young adults. RESULTS: MOCS dysfunction was shown in 126 ears of 65 patients (130 ears) with auditory neuropathy, 2 ears of 2 patients with unilateral acoustic neuroma, 4 ears of 2 patients with hyperacusis, 14 ears of 26 patients(48 ears) with normal hearing level in unilateral or bilateral tinnitus. Stronger EOAE could be recorded in total 146 ears with MOCS dysfunction at any pure tone hearing level. SOAE could be recorded in 126 of 146 ears (86.3%) with MOCS dysfunction and 44 of 128 ears (34.3%) with normal hearing. SOAE of ears with MOCS dysfunction was mainly at frequencies from 0.693 to 3.055 kHz and SOAE of normal ears was at frequencies from 1.135 to 2.746 kHz. Average value of maximum amplitude of SOAE spectrum (-3.4 +/- 6.4) dB SPL was significantly greater than that in normal ears (-6.8 +/- 7.8) dB SPL (P < 0.01). The major frequency range of SOAE (0.693-3.055 kHz) in MOCS dysfunction ears was essentially consistent with that of efferent suppression in normal ears (0.7-3 kHz). CONCLUSION: The modulation of the cochlear active mechanisms by MOCS mainly presents in the low- and mid-frequency regions, these frequencies correspond to the frequency range of SOAE. Stronger SOAE indicates pathophysiological significance. There is a clear clinical relationship between SOAE and the efferent modulation of the cochlea.

Adolescent↗

PubMed2001

[The effect of side chain structure on the excitation transfer and charge transfer processes in PPV/C60 composite system].

In this paper, we investigated the effect of side chains on the optical properties of PPV derivatives, the excitation transfer and charge transfer process in the PPV/C60 composite films. The results demonstrate that the absorption and PL emission bands of PPV shift towards lower photon energy with increasing of the length of PPV side chain, which indicates that energy gap of PPV derivatives become narrow with their side chain length increasing. In the PPV/C60 composite films, the emission of PPV derivatives was greatly quenched due to the efficient excitation transfer process between PPV and C60. We observed the absorption band of C60- located at 920 nm in the MD-PPV/C60 composite films, which reveals the existence of charge transfer process in the ground state of the composite films. This results show that the side chains of PPV derivatives not only influence the properties of absorbance and photoluminescence but also influence the electronic affinity of PPV polymers, which means that both physical and chemical properties of PPV can be monitored by controlling its side chain structure.

Electrochemistry↗