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Biomedical subjects

L Guo

Publications and source records attributed to L Guo.

At least 217 records · Page 12Linked to original sources
PubMed1998

Detection of retroviral antibodies in primary biliary cirrhosis and other idiopathic biliary disorders.

BACKGROUND: Retroviruses have been implicated in the aetiology of various autoimmune diseases. We used immunoblots as a surrogate test to find out whether retroviruses play a part in the development of primary biliary cirrhosis. METHODS: We did western blot tests for HIV-1 and the human intracisternal A-type particle (HIAP), on serum samples from 77 patients with primary biliary cirrhosis, 126 patients with chronic liver disease, 48 patients with systemic lupus erythematosus, and 25 healthy volunteers. FINDINGS: HIV-1 p24 gag seroreactivity was found in 27 (35%) of 77 patients with primary biliary cirrhosis, 14 (29%) of 48 patients with systemic lupus erythematosus, 14 (50%) of 28 patients with chronic viral hepatitis, and nine (39%) of 23 patients with either primary sclerosing cholangitis or biliary atresia, compared with only one (4%) of 24 patients with alcohol-related liver disease or alpha1-antitrypsin-deficiency liver disease, and only one (4%) of 25 healthy volunteers (p=0.003). Western blot reactivity to more than two HIAP proteins was found in 37 (51%) of patients with primary biliary cirrhosis, in 28 (58%) of patients with systemic lupus erythematosus, in 15 (20%) of patients with chronic viral hepatitis, and in four (17%) of those with other biliary diseases. None of the 23 patients with either alcohol-related liver disease or alpha1-antitrypsin deficiency, and only one of the healthy controls showed the same reactivity to HIAP proteins (p<0.0001). Our results showed a strong association between HIAP seroreactivity and the detection of autoantibodies to double-stranded DNA. HIAP seroreactivity was also strongly associated with the detection of mitochondrial, nuclear, and extractable nuclear antigens. INTERPRETATION: The HIV-1 and HIAP antibody reactivity found in patients with primary biliary cirrhosis and other biliary disorders may be attributable either to an autoimmune response to antigenically related cellular proteins or to an immune response to uncharacterised viral proteins that share antigenic determinants with these retroviruses.

Autoantibodies↗
PubMed1998

Induction of retinoblastoma gene expression during terminal growth arrest of a conditionally immortalized fetal rat lung epithelial cell line and during fetal lung maturation.

The process by which fetal lung epithelial cells differentiate into type 1 and type 2 cell is largely unknown. In order to study lung epithelial cell proliferation and differentiation we have infected 20-day fetal lung epithelial cells with a retrovirus carrying a temperature-sensitive SV40 T antigen (T Ag) and isolated several immortalized fetal epithelial cell lines. Cell line 20-3 has characteristics of lung epithelial cells including the presence of distinct lamellar bodies, tight junctions, keratin 8 and 18 mRNA, HFH8, and T1 alpha mRNA and low levels of surfactant protein A mRNA. At 33 degrees C 20-3 grows with a doubling time of 21 h. At 40 degrees C the majority of cells cease to proliferate. Growth arrest is accompanied by significant morphological changes including an increase in cell size, transition to a squamous phenotype that resembles type 1 cells, and an increase in the number of multinucleated cells within the population. Greater than 95% of the cells incorporate [3H]thymidine into DNA at 33 degrees C whereas at 40 degrees C label incorporation drops to less than 20%. When shifted down to 33 degrees C 40% of the cells remain terminally growth arrested. In addition, cells plated at 40 degrees C have a reduced ability to form colonies when replated at 33 degrees C. Treatment with TGF-beta increases the percentage of cells that terminally growth arrest to greater than 80%. Growth arrest is accompanied by an increase in the levels of c-jun, jun D, cyclin D1, C/EBP-beta, transglutaminase type II, and retinoblastoma (Rb) mRNA and an induction of p105, the hypophosphorylated, growth regulatory form of Rb. Evaluation of Rb mRNA in fetal lung indicates that it is induced 2.5-fold between 17 and 21 days of gestation. These studies indicate that 20-3 terminally growth arrests in culture at the nonpermissive temperature and that it may be useful in studying changes in gene expression that accompany terminal growth arrest during lung development.

Animals↗
PubMed1998

Molecular basis for persistent hepatitis B virus infection in the liver after clearance of serum hepatitis B surface antigen.

Hepatitis B virus (HBV) DNA has been detected by polymerase chain reaction (PCR) in the liver of patients with resolved chronic HBV infection and sustained clearance of hepatitis B surface antigen (HBsAg) from serum. However, it is unknown whether the virus is transcriptionally active at this time or if the covalently closed circular (CCC) replicative intermediate of HBV DNA can still be detected. Therefore, hepatic nucleic acid extracts from seven patients who had cleared serum HBsAg were assessed by (PCR) for either reverse-transcribed HBV RNA, or an intact direct repeat region of the HBV genome indicative of the CCC replicative intermediate of HBV DNA. HBV transcripts were detected in four of seven patients in the study group, whereas an intact direct repeat region of the HBV genome was detected in three. Evidence for viral transcription and replication was more frequently detected in patients who had recently cleared serum HBsAg, but HBV RNA was also detected in one patient 5 years after HBsAg clearance, and an intact direct repeat region of HBV DNA was detected in another subject at nearly 4 years after resolution of disease. Therefore, hepatic HBV transcription may be associated with replicative intermediates of persistent HBV DNA in patients who have cleared HBsAg from serum, suggesting that, on occasion, HBV may not be in a latent state but undergoing low-level replication.

Antigens, Viral↗
PubMed1998

Inhibition of tracheal vascular extravasation by liposome-encapsulated albuterol in rats.

PURPOSE: To develop a liposome-based system for systemic delivery of anti-inflammatory drugs to airways and other inflamed tissues. METHODS: Postcapillary venular gap junctions open during airway inflammation and allow fluid accumulation and permit molecules (e.g. complement, kininogen) to enter tissues, initiating inflammatory cascades. Beta-adrenergic agonists prevent inflammatory plasma extravasation, but because of their deleterious side effects, they are not used intravenously. When sterically stabilized "stealth" liposomes are injected i.v., they remain in the circulation for long periods. Inflammatory mediators [e.g., substance P(SP)] open postcapillary venular gaps and allow liposomes and their contents to be deposited selectively in the inflamed tissue. RESULTS: We hypothesized that liposomes encapsulating a beta-adrenergic agonist, such as albuterol, would deposit selectively in inflamed airway tissue, where the drug would slowly leak out of the liposomes, resulting in closure of the gaps, thus preventing subsequent inflammatory extravasation. To test this hypothesis, we delivered albuterol-loaded liposomes i.v. in rats. Then we injected SP to open the venular gaps and allow accumulation of the drug-loaded liposomes in airway tissue. We examined whether this treatment resulted in inhibition of subsequent plasma extravasation induced by SP. The results indicate that liposome-encapsulated albuterol inhibits subsequent extravasation, presumably by leaking out of liposomes in airway tissue. This inhibition occurs for prolonged periods of time and with limited side effects compared to the effect of free albuterol. CONCLUSIONS: We conclude that liposomes loaded with appropriate drugs, by migrating to inflamed tissue and subsequently inhibiting inflammatory cascades, may be of therapeutic value in inflammatory diseases.

Adrenergic beta-Agonists↗
PubMed1998

PmrA-PmrB-regulated genes necessary for 4-aminoarabinose lipid A modification and polymyxin resistance.

Antimicrobial peptides are distributed throughout the animal kingdom and are a key component of innate immunity. Salmonella typhimurium regulates mechanisms of resistance to cationic antimicrobial peptides through the two-component systems PhoP-PhoQ and PmrA-PmrB. Polymyxin resistance is encoded by the PmrA-PmrB regulon, whose products modify the lipopolysaccharide (LPS) core and lipid A regions with ethanolamine and add aminoarabinose to the 4' phosphate of lipid A. Two PmrA-PmrB-regulated S. typhimurium loci (pmrE and pmrF) have been identified that are necessary for resistance to polymyxin and for the addition of aminoarabinose to lipid A. One locus, pmrE, contains a single gene previously identified as pagA (or ugd) that is predicted to encode a UDP-glucose dehydrogenase. The second locus, pmrF, is the second gene of a putative operon predicted to encode seven proteins, some with similarity to glycosyltransferases and other complex carbohydrate biosynthetic enzymes. Genes immediately flanking this putative operon are also regulated by PmrA-PmrB and/or have been associated with S. typhimurium polymyxin resistance. This work represents the first identification of non-regulatory genes necessary for modification of lipid A and subsequent antimicrobial peptide resistance, and provides support for the hypothesis that lipid A aminoarabinose modification promotes resistance to cationic antimicrobial peptides.

Anti-Bacterial Agents↗
PubMed1998

Risk factors for glioma in adults: a case-control study in northeast China.

A case-control study of risk factors for glioma in adults was carried out in Heilongjiang province in northeast China. Between September 1989 and May 1995, 218 histologically confirmed cases of glioma requiring surgery for tumor removal (139 astrocytoma glioma and 79 other glioma) and 436 controls with non-neoplastic and non-neurological disease were recruited and personally interviewed in the wards of six major hospitals. Controls were matched by sex, age, and area of residence. Occupational, lifestyle, and medical information was obtained through a standardized questionnaire. Use of liquor was associated with cancer risk. Compared with males who never drank liquor, males with total lifetime liquor consumption of less than 1000 liters had an adjusted odds ratio (OR) of 1.60 (95% CI: 0.89-2.88) and for more than 1000 liters, 2.73 (95% CI: 1.06-7.08). Statistically significant associations were also found for diseases related to the brain (OR: 5.75; 95% CI: 1.08-30.47) and trauma to the head requiring medical attention (OR: 4.09; 95% CI: 2.51-10.31). Increased consumption of vegetables and of fruit were each associated with decreased glioma risk. Compared with lowest quartile intake, adjusted risks associated with highest quartile intake were 0.51 (95% CI: 0.29-0.89) for total vegetables and 0.28 (95% CI: 0.16-0.51) for total fruit.

Adult↗
PubMed1998

A case of syncytial giant cell hepatitis with features of a paramyxoviral infection.

Adult syncytial giant cell hepatitis (GCH) is an uncommon and often fulminant form of hepatitis that may be caused by infection with a novel paramyxo-like virus. We present the case of a 69-yr-old man who presented with acute, community-acquired hepatitis and chronic lymphocytic leukemia. A liver biopsy showed the typical findings of panlobular syncytial giant cell hepatitis. Electron microscopic examination demonstrated abundant nucleocapsid-like protein material in the cytoplasm and nuclei of affected hepatocytes. These structures were similar to, but distinct from, those of known paramyxoviridae, suggesting infection with a novel, related virus. In situ hybridization studies with a probe directed against the measles fusion protein gene gave a positive signal with a hepatocyte distribution. No signal was obtained with the measles nucleocapsid protein probe, suggesting that the disease agent was genetically distinct from, but related to, the measles virus. Subsequent liver biopsies were characterized by the gradual disappearance of the giant cell changes and by the concomitant development of cirrhosis. This is a case of adult GCH that resolved spontaneously and led to cirrhosis, thus implicating GCH as a potential cause of "cryptogenic" liver disease. Our findings provide further support for the existence of a distinct, as yet unidentified viral species as a cause of this disease.

Aged↗
PubMed1998

Potassium and chloride channels in freshly isolated rat odontoblasts.

It has been suggested that understanding the physiological properties of odontoblasts may be important in understanding the mechanisms underlying both metabolic and transductive processes in dental pulp. Because ion flux(es) may play a critical role in these events, it is of particular interest to understand ionic mechanisms in odontoblast cells. Thus, the aim of this study was to use patch-clamp recording techniques to examine the properties of resident ion channels in freshly dissociated odontoblasts. In recordings made in potassium-rich solutions, cells displayed at least three distinct channel amplitudes, with conductances of 130 +/- 18 pS, 52 +/- 4 pS, and 25 +/- 2 pS, respectively. Channel activity persisted in the presence of potassium salts of impermeant anions, and could be abolished by barium, a non-specific potassium channel blocker. In addition to the potassium conductances, we saw two separate anion channels in the odontoblast membrane. These channels were predominantly chloride-selective, weakly permeable to both acetate and aspartate, and had conductances of 391 +/- 64 pS and 24 +/- 3 pS. While questions remain regarding the functional role of these and other ion channels that presumably reside in the odontoblast membrane, our results demonstrate that it is possible to study ionic mechanisms of the odontoblast at the level of the single cell.

Animals↗
PubMed1998

[The study on the anti-tumor function of lysozyme in the regional lymph nodes of laryngocarcinoma patients].

The purpose of this study was to discuss the anti-tumor function of lysozyme (LZM) to laryngocarcinoma. The LZM distribution of regional lymph nodes incised from laryngocarcinoma patients in paraffin sections was observed by immunohistochemical technique. By the cell culture technique, autologus laryngocarcinoma cells were used as target cells to evaluate the tumoridical activity of MØ which were isolated from the regional lymph nodes of laryngocarcinoma patients. At the same time, ConA was added as control group. The supernatant of cell culture was collected after 24 hours to detect LZM content. The results indicated that the number of LPM in non-metastatic lymph nodes was significantly more than in metastatic lymph nodes (P < 0.01). The MØ isolated from patients' regional lymph nodes released LZM content and it's tumoridical activity to autologus tumor cells were significantly increased after adding ConA (P < 0.01). The LZM releasing content and tumoridical activity of MØ in non-metastatic lymph nodes were much more than metastatic lymph nodes (P < 0.05). The LZM content and tumoridical activity of MØ were analyzed with linearity relapsing statistics, it was positive linearity relation (r = 0.94, P < 0.01). All above suggests that the LZM of laryngocarcinoma patients is closely related to the anti-tumor function, it improves the tumoridical activity of MØ to autologus laryngocarcinoma cells and accelerates the death of laryngocarcinoma cells.

Adult↗
PubMed1998

[Pathological characteristics of gonads in nine patients with true hermaphroditism].

OBJECTIVE: To investigate the gonadal histopathology of true hermaphroditism and its correlation with the clinical features. METHODS: Clinico-pathological materials and chromosomal karyotypes from 9 true hermaphroditisms were reviewed. RESULTS: Seven out of 9 patients aged 5-21 years had been raised as females, and the other two were raised as males. Ovotestis was the most common form of the abnormal gonads, 2 out of 9 patients had bilateral ovotestes, 7 had unilateral ovotestes (5 in right side, 2 in left side). In the 7 patients with unilateral ovotestis, 6 had a contralateral ovary and one had a contralateral testis. Microscopically, the ovarian tissue of 11 ovotestes, including 6 biopsies from contralateral ovaries were normal, with many primordial follicles and a few growing follicles. In two of the patients, aged over 15 years, evidence of ovulation was observed. In comparison, the testicular tissue of the ovotestis and one left inguinal testis was histologically abnormal. Two of the 9 patients conceived and delivered normal infants by cesarean section after surgical treatment. CONCLUSION: Identification of the gonadal histopathology in these cases is important in order to make a correct scheme for the treatment.

Adolescent↗
PubMed1998

[Significance of bcl-2 gene breaking and bcl-2 protein expression in nasopharyngeal carcinoma].

In order to study the relationship between bcl-2 gene and nasopharyngeal carcinoma. The two hot breakpoints of bcl-2 gene and bcl-2 protein expression were examined by in situ hybridization and immunohistochemistry technique in 41 nasopharyngeal carcinoma(NPC) tissues. bcl-2 gene breakpoint were found in 4 cases of NPC(positive rate 9.8%). 34 cases of NPC expressed bcl-2 protein, the positive incidence was 82.9%. No statistically significant differences was found in histological grades. All benign lesions were negative for bcl-2 gene breaking and bcl-2 protein expression. There was no corresponding relation between bcl-2 protein expression and bcl-2 gene breaking. The results implicated that bcl-2 gene breaking may not play an important role in the pathogenesis of NPC. It also suggested that overexpression of bcl-2 protein may involved in carcinogenesis of nasopharyngeal epithelium.

Carcinoma, Squamous Cell↗
PubMed1998

[Pathological changes of early intestinal tuberculosis].

OBJECTIVE: To probe into the characteristics of pathological changes of early intestinal tuberculosis. METHOD: Three cases of early intestinal tuberculosis proved by colonoscopy were reported and analyzed. RESULT: Hyperemia and edema of the ileocecal mucosa were found. The involved mucosa looked friable and eroded, which was covered by fibrinopurulent exudates or forsty white mucus. The ileocecal valve was edematous and deformed. Tuberculous tubercles were found in intramucosal tissue under microscopy. Neither ulceration nor fiberous hypertrophy was found. CONCLUSION: It shows important significance to recognize the pathological manifestations of early intestinal tuberculosis for diagnosis of the disease.

Adult↗
PubMed1998

[Screening of enhancers for permeation of berberine in ruyi patcher in vitro].

To screen the best kinds and doses of enhancers for Ruyi Patcher, the effect of azonc(A) and propanediol (P) on the permeation of berberine(BR) from Ruyi Patcher in vitro was studied using improved Franz diffuse cells and the permeated berberine was determined by HPLC. The result showed that 3% of A in combination with 10% of P had synergistic effect, which helped enhance the skin permeation of BR significantly(P < 0.01). Therefore, a combination of 3% A and 10% P is the best enhancer for Ruyi Patcher and the penetration process of BR could be described by one-order kinetics.

Animals↗
PubMed1998

[Cloning and secretory expression of staphylokinase in Streptomyces lividans].

OBJECTIVE: Construct a recombinant Streptomyces strain by which staphylokinase can be secretory expressed. METHODS: With the total DNA extracted from strains of Staphylococcus aureus isolated in clinic as template DNA, one 730 bp DNA fragment including secretory signal peptide sequence and structure gene of staphylokinase was amplified by PCR. After cloning into plasmid pUC19 and sequencing, this fragment was confirmed to have the same nucleotide sequence as that of staphylokinase gene reported before. Then the fragment was inserted into Streptomyces plasmid pIJ459 following strong promoter. Recombinant plasmid pIJ459SAK was transformed into S. lividans TK54. RESULTS: The 72 hours culture supernatant of the secretory-type genetic engineering strain that harbored pIJ459SAK was analyzed by 15% SDS-PAGE. One specific protein band with molecular weight about 16,000 can be seen after staining the gel with silver nitrate. The fibrinolytic activity of Staphylokinase can be also detected in the 72 hours culture supernatant in the fibrin-plate assay. CONCLUSIONS: Staphylokinase can be successfully secreted into fermentation culture by the recombinant Streptomyces strain.

Cloning, Molecular↗
PubMed1998

[Low semi-cystectomy in treating trigone of bladder neck carcinoma].

OBJECTIVE: To resect the tumor in trigone and bladder neck and remain urination function. METHOD: A new procedure low segmental-cystectomy which includes resection of the trigone of bladder, prostate, seminal vesicles, extremity of ureter, was performed on 8 patients aged 28 to 57 years. RESULT: The patients were followed up for 6 months to 3 years. No recurrent tumor and metastasis were found, and urination function was normal. CONCLUSION: This procedure is superior to Bricker's operation, Kock pouch bladder and ileal neo-bladder. The patients enjoy good life quality after operation.

Adult↗