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Biomedical subjects

H Ren

Publications and source records attributed to H Ren.

At least 109 records · Page 6Linked to original sources
PubMed1997

The effect of a shear force on the cell shedding rate of the corneal epithelium.

PURPOSE: During blinking the lids apply a shear force to the corneal epithelium. The aim of this study was to determine if a shear force applied to the epithelial surface increases the rate at which cells shed. METHODS: The shedding rate was studied in perfused whole rabbit eyes, and the effect of a shear force examined by exposing the corneas to a stirred solution. Control corneas were exposed to a static solution. The shedding rate and size of shed cells were measured, and the number of terminally differentiated cells on the corneal surface determined after 6 h of perfusion using ethidium bromide. RESULTS: Compared with controls, the shear force increased the cell shedding rate from the corneal surface significantly (p < 0.01, paired t-test). The increase was due to small cells with a longest dimension less than 25 microm. The number of terminally differentiated cells on the epithelial surface did not increase. CONCLUSION: Because of the decrease in size, and the change in appearance of shedding cells, it is proposed that the increase in cell shedding rate was due to an increase in the number of apoptotic cells, and not to an increase in terminally differentiated cells. It is suggested that in the human eye, under adverse conditions, shear forces due to blinking may play a role in creating apoptotic cells.

Animals↗
PubMed1997

[Discordance of increase in stress proteins in right and left myocardium of perfused isolated rat heart].

Discordance of functional and structural changes in right and left myocardium has been considerably discovered in various physiologically stimulated hearts and patients with cardiopathy, but the reasons for that have not yet been known. In the present study, induction of stress proteins, i.e. heat shock proteins, was analyzed and compared between the left and right myocardium of normoxic and hypoxic perfused isolated rat hearts by the methods of two dimensional electrophoresis and silver staining. The results showed that three Hsp70 isoforms (molecular weight 68, 70 and 72 k mu) with pI ranging from 6.3 to 7.3 were increased distinctly in both right and left myocardium under the conditions of perfusion as mentioned above. Moreover, the amount of the stress proteins increased in the right myocardiums was higher than that in the left myocardium, indicating that the response of right heart to the stimulus of hypoxic or normoxic perfusions is different from the reaction of left heart, and the extent of protection in left and right heart by stress proteins is unlike. In addition, the activity of catalase was found to be obviously declined in all perfused isolated hearts. It was suggested that the different increase in stress proteins may be due to different structure and status of right and left ventricle and the oxidative stress may be one of the important reasons to induce or enhance the synthesis of stress proteins.

Animals↗
PubMed1997

[Partial deletion of mitochondrial DNA in mitochondrial encephalomyopathies].

OBJECTIVE: To characterize the deletions of mitochondrial DNA (mtDNA) in Chinese patients with Kearns-Sayre syndrome (KSS) and chronic progressive external ophthalmolegia (CPEO) and identify deletion mutations of mtDNA be the etiology of these diseases. METHODS: Patients and preparation of total DNA: Two patients with KSS and two with CPEO and ten with other mitochondrial myopathies or encephalomyopathies were determined by histological and biochemical assays. Total DNA was isolated from 100 mg to 150 mg of frozen muscle obtained by biopsy using the methods described by Zeviani et al. (1988). Preparation of mtDNA probes: MtDNA were isolated and purified according to Palva's method (1985). The mtDNA was linearized by digestion with the restriction endonuclease Pvu II and separated by electrophoresis through low melting agarose gel. The 16.5 kb DNA band was recovered from the gel and labeled with alpha-p32 dCTP by random primer labeling. Southern blot analysis: Portions of five micrograms total DNA obtained from the patients and controls were digested with Pvu II, EcoR I, Hind III And Xba I respectively. The digested DNA was separated by agarose gel electrophoresis and transferred to nitrocellulose membrane and then hybridized with P32 labeled mtDNA as previously described (Zhang, 1991). RESULTS: A large-scale deletions of mtDNA were identified in two patients with KSS and two patients with CEPO. The deletions ranged in size from 2.4 kb to 5.5 kb. The proportion of mutated mtDNA in each patients ranged from 54.6% to 84.6% of total mtDNA. No detectable deletions were found in mtDNA of ten patients with other mitochondrial myopathies or encepholomyopathies and normal controls. CONCLUSIONS: Deletions of mtDNA were found in all KSS and CEPO patients detected. These results supported The view point of the deletions are important causes of physical defect in KSS and CEPO.

DNA, Mitochondrial↗
PubMed1997

[Application of rigid bronchoscopy in airway management after lobectomy of lung].

OBJECTIVE: Application of rigid bronchoscopy in airway management after lobectomy of lung was recommended, and its significance was discussed. METHODS: Bronchoscopies were performed in three patients scheduled for lobectomy of lung undergoing epidural plus general anesthesia. Each patient was examined two times. The first examination was done after anesthetic induction and intubation. The second was given at the end of operation. RESULTS: Rigid bronchoscopy under general anesthesia could clearly show the inner structures of trachea, bronchi and location of carcinoma. Under direct version, the secretion and sludged blood in the trachea and bronchi after lobectomy could be scavenged. CONCLUSION: It was suggested that with the use of bronchoscopy the complications including postoperative atelectasis and bronchial-pleural fistulization could be reduced.

Adult↗
PubMed1997

[Preparation method of foamed aerosol for use in vagina].

The extraction of medicinal materials, compatibility of liquor and prescription of emulsion for use in vagina were observed. The result shows that through compound extraction, removal of tannic materials, decolorization and water precipitation, with propylene glycol and ethylene glycol as latent solvent and using lactic acid to adjust to pH4.5, a clarified solution can be obtained, and then with the help of Tween-spans emulisifying agent and propellant the stable emulsion is formed.

Administration, Intravaginal↗
PubMed1997

Pulmonary leiomyosarcoma.

Three cases of pulmonary leiomyosarcoma were presented. The characteristic clinical features were described with review of literature. In comparison with bronchogenic carcinoma, the leiomyosarcoma has some characteristics: 1) On chest X-ray, it usually appears as a sharply demarcated, even density round mass, growing rapidly within the lung, it unusually accompanies with hilar or mediastinal lymph node metastasis; 2) The preoperative cytological or pathological diagnosis is difficult either by sputum smear or by bronchoscopic biopsy or by fine needle percutaneous aspiration biopsy; 3) Pathological differential diagnosis of leiomyosarcoma of lung from anaplastic lung cancer is difficult. In conclusion, the primary pulmonary leiomyosarcoma is a rare malignant tumor, detecting the present illness seriously, paying attention to the chest X-ray films characterize, early surgical resection is the only way to get diagnosis and effective treatment method.

Adult↗
PubMed1997

Diagnosis and treatment of stage-III peripheral squamous cell carcinoma of right upper lung.

During a 12-year period, 44 patients were surgically treated for stage-III peripheral squamous cell carcinoma of the right upper lobe. The mean time from the discovery of the shadow in the right upper lobe to the confirmation of the diagnosis was 2 months. All patients underwent the resection of the right upper lobe with the dissection of the right mediastinal lymph nodes, among them, 4 patients had sleeve lobectomy of the right upper lobe. P-TNM staging: 23 cases were in stage-IIIa, 21 cases in stage-IIIb. The frequency of the postoperative complications was 20.4% (9/44 cases). The 1-year survival rate of all patients was 61% (27/44 cases). None of stage-IIIb patients lived longer than 3 years. The postoperative 3- and 5-year survival rates of stage-IIIa cases were 65.2% (15/23 cases) and 21.7% (5/23 cases) respectively. In this article, the patients' clinical features, the causes of delayed-diagnosis, the operative and postoperative management were discussed. We suggest that the stage-IIIa patients should be given surgical treatment, whereas, for the patients of stage-IIIb, palliative operation was given just for the purpose of reliving the symptoms.

Aged↗
PubMed1997

[Influence of leaf-picking on effective constituents of the Astragalus mongholicus roots].

After the application of the orthogonal design, experiments show that the proportion and time of leaf-picking have a great influence not only on the total content of 17 kinds of amino acids but also on that of Astragaloside. If the proportion is large and the time is delated, both contents of 17 kinds of amino acids and Astragaloside will be reduced accordingly compared to the control group. There is less influence on the contents if the time of leaf-picking is set on June 15 each year and the picking proportion is 1 out 3.

Amino Acids↗
PubMed1997

[Studies on the relationship between purified alpha class glutathione S-transferase (GST-alpha) and hepatocellular damage].

Using our ELISA kit for GST-alpha, we tested the serum GST-alpha levels of patients with hepatitis A, acute hepatitis B (HB), chronic active HB, chronic persistent HB and liver cirrhosis. Serum GST-alpha levels in all these groups of patients were significantly higher than those in the controls (P < 0.01). Serum GST-alpha levels was closely (P < 0.01) correlated with serum alanine transaminase (ALT) levels in various groups of patients except chronic persistant HB. The combined application of the two markers, GST-alpha and ALT, raised the sensitivity of detection for liver diseases. In detection of chronic persistent HB patients, the GST-alpha marker was more sensitive than ALT (P < 0.01). The follow-up data of GST-alpha and ALT markers in serum showed that the GST-alpha level could reflect the clinical progression of liver disease more exactly as observed in 79 liver cancer patients in then GST-alpha and ALT positive rate were 81% and 61% respectively (P < 0.01). In 30 persons with positive HBsAg, the positive rates of GST-alpha and ALT were 70% and 37%, respectively. These results indicated that, (1) the detection of GST-alpha combined with ALT was capable of increasing the sensitivity for recognizing hepatocellular damage; (2) the elevation of serum GST-alpha level mainly resulted from the increased expression of GST-alpha in liver cells during hepatocarcinogenesis, thus, the GST-alpha is thought to be a tumor marker for liver cancer; (3) GST-alpha measurement offers advantage over ALT for the detection of minor degree of hepatocellular damages. GST-alpha may act as an early, sensitive and specific enzyme marker.

Alanine Transaminase↗
PubMed1997

[Effect of combination of herbimycin A, an inhibitor of tyrosine kinase, and chemotherapeutic agents on apoptosis of K562 cells].

OBJECTIVE: To explore the anti-apoptotic mechanism and the apoptosis-inducing method in chronic myeloid leukemia (CML) cells. METHODS: K562 cell line was used to observe the effect of combination of herbimycin A (HMA), a tyrosine kinase inhibitor, and chemotherapeutic agents on the induction of apoptosis. RESULTS: HMA or chemotherapeutic agents could inhibit the proliferation but not significantly induce apoptosis of K562 cells. However, HMA significantly enhanced apoptosis when combined with chemotherapeutic agents. Addition of sulfhydryl compound to the cultures to conjugate HMA completely abrogated this enhancing effect on K562 cells. CONCLUSION: HMA increases the sensitivity of CML cells to chemotherapeutic agents by inactivating tyrosine kinase activity. It is promising that combination of HMA with conventional chemotherapeutic drugs in the treatment of CML.

Antineoplastic Agents↗
PubMed1997

[Granulocyte-macrophage colony-stimulating factor and erythropoietin induce tyrosine phosphorylation and activation of JAK2].

OBJECTIVE: In order to identify the tyrosine kinase (s) that may associate with cell proliferation. METHODS: GM-CSF/Epo responsive cell UT-7 and Epo responsive cell UT-7/Epo were used for study of tyrosine phosphorylation. RESULTS: The addition of GM CSF and/or Epo to the responsive cells induced rapid tyrosine phosphorylations of 145000, 130000, 80000 and 40000 cellular proteins. The tyrosine phosphorylated 130000 protein was identified as JAK2, a non receptor tyrosine kinase. GM CSF and Epo also activated its tyrosine kinase activity. Tyrosine phosphorylation and activation of JAK2 only occurred in GM-CSF and/or Epo-responsive cells. CONCLUSION: JAK2 signal transduction pathway may play an important role in regulating the proliferation of hematopoietic cells induced by GM-CSF and Epo.

Cell Line, Tumor↗
PubMed1997

Adherence of Pseudomonas aeruginosa to shed rabbit corneal epithelial cells after overnight wear of contact lenses.

PURPOSE: Previous studies have shown that contact lens oxygen transmissibility correlates with binding of Pseudomonas aeruginosa to the rabbit cornea after overnight lens wear. Studies of human lens wear stratified by oxygen transmissibility will be required to validate these animal results. In humans, bacterial binding to shed cells obtained through corneal irrigation cytology may provide an indirect measure of in vitro binding. The purpose of this study was to establish the relationship between binding to shed cells and to the residual corneal surface in an animal model of lens wear prior to initiation of human studies. METHODS: The test contact lenses used were: rigid lens A (Dk/L = 10 x 10(-9) [cm/ sec][mL O2/mL mmHg]); rigid lens B (Dk/L = 97); soft lens A (Dk/L = 9); soft lens B (Dk/L = 20); and, soft lens C (Dk/L = 39). There were six rabbits in each group, except for the soft lens C group, which had seven rabbits. After overnight lens wear, the corneal surface was irrigated with a corneal irrigation chamber to collect surface cells before exposure to a bacterial suspension (1 x 10(7) CFU/mL) for 30 minutes. The number of bacteria adherent to the residual corneal surface was then assessed by CFU determination. Cells collected from the corneal surface (9 mL) were incubated with 1 mL bacterial suspension containing 10(8) (CFU/mL) for 30 minutes. The number of bacteria adherent to shed cells was assessed by staining with acridine orange and direct counting by epifluorescence microscopy. RESULTS: The differences in the number of bacteria adhering to shed epithelial cells between the treated and the control eyes were 2.90 +/- 1.20 and 0.23 +/- 0.41 for rigid lenses A and B, respectively, and 5.97 +/- 1.54, 3.67 +/- 2.32, and 0.90 +/- 1.45 (bacterial/cell) for soft lenses A, B, and C, respectively. Overnight contact lens wear induced a significant increase in bacterial binding to shed corneal epithelial cells for rigid lens A and for soft lenses A and B. There were significant differences among lens groups (P = 0.00017, ANOVA), with significant differences between rigid lenses A and B, soft lenses A and C, and soft lenses B and C. The binding of bacteria to shed cells was significantly correlated with the binding of bacteria to the residual corneal surface, both confirming and extending previous results (R = 0.78, P < 0.001). CONCLUSION: These results demonstrate a positive correlation between P. aeruginosa adherence to shed corneal cells and to the residual corneal surface in the rabbit eye following contact lens wear. In light of the results from prior animal studies, examination of the behavior of P. aeruginosa binding to exfoliated cells appears to be a promising and valid method for future assessment of similar lens-induced increases in bacterial binding in prospective human clinical studies.

Animals↗
PubMed1997

Guillain-Barré syndrome: clinical analysis and pathological study on sural nerve biopsy of forty cases.

OBJECTIVE: To make clinical analysis and pathological study on 40-case Gullain-Barré syndrome with sural nerve biopsy. METHODS: A total of 90 cases of GBS were retrospectively analyzed of which sural nerve biopsies were performed in 40 cases. The type of GBS was determined according to Asbury and Ropper criteria, and its correlation with pathological findings was studied. RESULTS: In the 40 biopsy cases, demyelination was the predominant pathological change in 38 cases. Mild axonal degeneration was also seen in 13 of the 38 cases. Prominent axonal degeneration was seen in only 2 of 13 cases. The increased monocyte infiltration and varied capillary permeability were observed in 19 of 25 cases. Onion-bulb like changes were seen in 6 cases. CONCLUSION: We studied the correlation between paresthesia and the pathological findings of sural nerve biopsy and concluded that sural nerve biopsy is very useful in the diagnosis of GBS and its variant.

Adolescent↗
PubMed1997

Clinical, pathologic and genetic studies on mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes.

OBJECTIVE: To study the clinical, pathological and genetic characteristics of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). METHODS: Eight cases of MELAS (6 of them were from 2 families) underwent clinical study, muscle biopsy, autopsy on one patient, brain biopsy on one patient and genetic research. RESULTS: In clinical report the average age of onset was 10-22 years old. Four cases from one family were 3 brothers and their nephew (sister's son). The death age of the three brothers was 16-20 years. Two cases from another family were a brother and a sister. The six patients of the two families showed the typical inherited characters of MELAS. The symptoms were myoclonic epilepsy, stroke-like episodes, paralysis of limbs, progressive mental retardation and neurological deaf. CT showed calcification in globus pallidus and MRI demonstrated clearly the abnormal prolongation of T2-weighed signals that distributed in frontal, parietal, occipital and temporal cortex as multiple focal, cystic and laminar necrotic areas. Pathological studies on brain showed multi-focal, cystic, and laminar or spongy necrotic abnormality primarily in gray matter of frontal, parental, temporal and occipital cortex. Decrease and loss of nerve fibers of the sub-cortical white matters of the lesion areas of cortex and calcification of globus pallidus were also observed. Red ragged fibers (RRF) and abnormal mitochondron were found by muscle biopsies. A point mutation (A-G transition) at nt 4243 in the mitochondrial tRNA Leu (UUR) was confirmed by using PCR and Southern Blot. CONCLUSION: Although great progress has been made in the clinical, pathological and genetic research of MELAS, the pathogenesis of the disease remains further research.

Adolescent↗
PubMed1996

Huperzine A, a novel promising acetylcholinesterase inhibitor.

The effects of huperzine A on memory impairments induced by scopolamine were evaluated using a radial maze task and inhibition of cholinesterase in vitro compared with the effects of E2020 and tacrine. Scopolamine (0.2 mg kg-1) significantly impaired spatial memory in rats. Huperzine A (0.1-0.4 mg kg-1, p.o.), E2020 (0.5-1.0 mg kg-1, p.o.) and tacrine (1.0-2.0 mg kg-1, p.o.) could reverse these scopolamine-induced memory deficits. The ratios of huperzine A, E2020 and tacrine for butyrylcholinesterase:acetylcholinesterase determined by a colourimetric method were 884.57, 489.05, and 0.80, respectively. The results demonstrated that huperzine A was the most selective acetylcholinterase inhibitor, and improved the working memory deficit induced by scopolamine significantly better than did E2020 or tacrine, suggesting it may be a promising agent for clinical therapy of cognitive impairment in patients with Alzheimer's Disease.

Acetylcholinesterase↗
PubMed1996

Leptin is a metabolic signal to the reproductive system.

Leptin, a newly-discovered hormonal product of the obese (ob) gene, is expressed by adipocytes and thought to play a role in the regulation of food intake and metabolism. We tested the hypothesis that leptin signals metabolic information to the reproductive system by examining its effects on the reproductive system of ob/ob mice, which have a congenital deficiency in leptin and are infertile. We treated pair-fed males and females with leptin (50 microg twice daily, ip) or vehicle (n=10/group) for 14 days, after which the animals were bled and killed. Leptin-treated females had significantly elevated serum levels of LH, increased ovarian and uterine weights, and stimulated aspects of ovarian and uterine histology compared to controls. Leptin-treated males had significantly elevated serum levels of FSH, increased testicular and seminal vesicle weights, greater seminal vesicle epithelial cell height, and elevated sperm counts compared to controls. These results demonstrate that leptin stimulates the reproductive endocrine system in both sexes of ob/ob mice and suggest that leptin may serve as a permissive signal to the reproductive system of normal animals.

Analysis of Variance↗
PubMed1996

The cell shedding rate of the corneal epithelium--a comparison of collection methods.

PURPOSE: To determine the spontaneous shedding rate of cells from the rabbit corneal epithelium using different harvesting methods. METHODS: Cells were collected from the rabbit corneal epithelium using two in vitro methods and three in vivo methods. Cells were counted and the shedding rate calculated after adjustment for the collection time. RESULTS: The shedding rates obtained from the in vitro methods were (cells/min/cornea, mean +/- SE): 78.0 +/- 9.4 (corneal superfusion), and 5.4 +/- 1.3 (whole-eye perfusion). For the in vivo corneas, the shedding rates were: 10.0 +/- 2.3 (corneal superfusion), 8.1 +/- 0.4 (corneal immersion), and 14.5 +/- 1.5 (corneal irrigation). In vitro corneal superfusion was significantly different from the other four methods (P < 0.01). CONCLUSIONS: The results suggest that the spontaneous cell shedding rate of the in vivo rabbit corneal epithelium is 5 to 15 cells/min/cornea. This is much lower than estimates of about 100 cells/min/cornea based upon in vitro corneal superfusion. One explanation of this slow shedding rate is that factors which were absent during our collection methods (such as blinking) would normally increase shedding. Another possibility is that cells in the corneal epithelium may have a much longer life span than previously reported; rather than a few days, the epithelium could take several months to completely replace all cells. Whatever the explanation, the measured spontaneous shedding rate does not complement the reported production rate of new cells. It is necessary to revise our understanding of the kinetics of epithelial homeostasis.

Animals↗