Biomedical subjects

S Guo

Publications and source records attributed to S Guo.

At least 73 records · Page 4Linked to original sources

PubMed2000

Characterization of some O-acetylated saponins from Quillaja saponaria Molina.

Sixteen saponins were identified from a bark extract of Quillaja saponaria Molina. The compounds were characterized, using NMR spectroscopy, mass spectrometry and monosaccharide analysis, as quillaic acid substituted at C-3 with oligosaccharides consisting of a disaccharide, beta-D-Galp-(1-->2)-beta-D-GlcpA substituted with either D-xylose or L-rhamnose and at C-28 with complex oligosaccharide structures consisting of a disaccharide, alpha-L-Rhap-(1-->2)-4-O-acetyl-beta-D-Fucp, substituted with various amount of D-xylose. D-glucose, D-apiose, and L-rhamnose.

Acetylation↗

PubMed2000

Structural studies of triterpenoid saponins with new acyl components from Quillaja saponaria Molina.

Eight new triterpenoid saponins were isolated from a bark extract of Quillaja saponaria Molina by silica and reverse phase chromatography. The saponins were characterized by spectroscopic data and chemical methods as phytolaccagenic acid, 22beta-hydroxy-quillaic acid, and echinocystic acid substituted with different oligosaccharides at C-3 and C-28. The O-4 of the fucosyl residue in the 28-O-oligosaccharide was substituted with either acetyl, (S)-2-methylbutanoyl, or (3S,4S)-3-hydroxy-4-methylhexanoyl groups.

Carbohydrate Conformation↗

PubMed2000

Triterpenoid saponins containing an acetylated branched D-fucosyl residue from Quillaja saponaria Molina.

Seven novel saponins were isolated from a bark extract of Quillaja saponaria Molina. the compounds were characterized, using mainly NMR spectroscopy, mass spectrometry and chemical methods, as quillaic acid substituted at C-3 with oligosaccharides consisting of various compositions of D-glucuronic acid D-galactose, D-xylose, and L-rhamnose and at C-28 with complex oligosaccharide structures consisting of various compositions of D-xylose, L-rhamnose, D-apiose and a branched 4-O-acetyl-D-fucose residue.

Acetylation↗

PubMed2000

Drinks like a fish: zebra fish (Danio rerio) as a behavior genetic model to study alcohol effects.

Zebra fish may be an ideal vertebrate model system for numerous human diseases with which the genetics and biological mechanisms of the disease may be studied. Zebra fish has been successfully used in developmental genetics, and recently, neurobiologists have also started to study this species. A potentially interesting target disease amenable for analysis with zebra fish is drug addiction, e.g. alcoholism. Although genetic tools to manipulate the genome of zebra fish are available, appropriate phenotypical testing methods are often lacking. In this paper, we describe basic behavioral tests to investigate the acute effects of alcohol on zebra fish. These behavioral paradigms will be useful for the genetic and biological analysis of acute and chronic drug effects as well as addiction. In addition to presenting findings for the acute effects of alcohol, we briefly describe our strategy for generating and screening mutants. We hope that our pilot work will facilitate the future development of behavioral tests and the use of zebra fish in the genetic analysis of the biological effects of drugs of abuse.

Aggression↗

PubMed2000

Seasonal abundance of the parasitoid complex associated with the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) in Hangzhou, China.

An investigation of insect parasitoids of the diamondback moth, Plutella xylostella (Linnaeus), in brassica vegetable crops in the suburbs of Hangzhou was conducted during five periods from 1989 to 1997. Eight species of primary parasitoids were recorded: Trichogramma chilonis Ishii, Cotesia plutellae Kurdjumov, Microplitis sp., Oomyzus sokolowskii Kurdjumov, Diadromus collaris (Gravenhorst), Itoplectis naranyae (Ashmead), Exochus sp. and Brachymeria excarinata Gahan. Seven species of hyperparasitoids were also collected. Rates of parasitism of eggs of P. xylostella were usually very low. However, rates of parasitism of larvae and pupae were substantial and showed two peaks each year, around June-July and September-November respectively. Rates of parasitism during peaks were usually 10-60% and reached over 80% on a few occasions. Cotesia plutellae, O. sokolowskii and D. collaris were the major larval, larval-pupal and pupal parasitoids respectively. In the field, C. plutellae was active throughout the year. Oomyzus sokolowskii was active from May to October, entered a quiescent pupal stage in October-November to overwinter and did not emerge until next April-May. Diadromus collaris was recorded from April to July and October. Rates of parasitism of P. xylostella in radish and mustard fields were usually higher than those in cabbage and Chinese cabbage fields in the same locality. Negative correlations of parasitism rates between C. plutellae and O. sokolowskii indicate a competitive relationship for host larvae between these two larval parasitoids.

Animals↗

PubMed2000

Comparison of endothelial cell density estimated by contact and non-contact specular microscopy.

PURPOSE: To compare a contact and a non-contact specular microscope in the determination of endothelial cell density. SUBJECTS AND METHODS: One hundred and twenty-one eyes from 70 patients who had undergone various degrees of photorefractive keratectomy for myopia were included. The endothelium was imaged by contact (Konan Clinical Specular Microscope) and non-contact (Topcon SP-1000) specular microscopy and the endothelial cell density estimated. RESULTS: The average endothelial cell density achieved by the contact specular microscope was 3011+/-298 cells/mm2 (mean+/-SD, n=121) and by the non-contact specular microscope 3015+/-265 cells/mm2 (n= 121). The difference in endothelial cell density between the contact and the non-contact specular microscope (contact minus non-contact) was -4+/-175 cells/mm2 (t=0.26, 2p>0.05 in a paired t-test). The sampling error on the estimated endothelial cell density was 76 cells/mm2 for the contact specular microscope and 74 cells/mm2 for the non-contact specular microscope. CONCLUSION: The average endothelial cell density and the precision of the measuring technique were similar for the contact and the non-contact specular microscope. Furthermore, the endothelial cell densities estimated by the two instruments at various values of anterior central corneal refractive power and central corneal thickness were similar. The two instruments can be used interchangeably.

Adult↗

PubMed2000

Antibody responses against Porphyromonas gingivalis infection in patients with early-onset periodontitis.

BACKGROUND, AIMS: The aim of this study was to evaluate antibody responses against Porphyromonas gingivalis (P. gingivalis) infection in early-onset periodontitis (EOP) patients to elucidate further the host-parasite interactions in the pathogenesis of EOP. METHOD: 16 P. gingivalis-infected EOP and 20 adult periodontitis (AP) patients, and 18 periodontally healthy subjects (HS) participated in this study. Serum immunoglobulin G (IgG) antibody levels and avidities against extracted P. gingivalis whole cells were measured. The components of P. gingivalis outer membrane antigens (OMA) reacting to patients' sera were analysed from the molecular weights by Western blotting. Serum antibody levels against P. gingivalis lipopolysaccharide (LPS) were also measured. The ability of the patients' sera to block interleukin-1beta (IL-1beta) production by human mononuclear cells in response to P. gingivalis LPS was examined. RESULTS: Antibody levels were positively correlated with antibody avidities in both EOP and AP patients (r=0.91, r=0.72, p<0.0005, respectively), while not significantly so in HS (r=0.09). There was variability in the antigen recognition of P. gingivalis OMA in EOP and AP patients. Smear and 53-kDa protein were more frequently recognized by sera of EOP and AP patients rather than that of HS (p<0.05). The smear was partly diminished by absorption with P. gingivalis LPS, indicating the smear antigen was partly composed of LPS. There was high correlation between antibody levels against P. gingivalis whole-cell extracts and LPS in EOP and AP patients (r=0.81, p=0.0002, r=0.87, p<0.0001, respectively), while not significant in HS (r=0.22). The sera of EOP and AP patients with high IgG titre to P. gingivalis LPS blocked IL-1beta production more effectively than that of the patients with low IgG titre to P. gingivalis LPS. CONCLUSIONS: These results indicate that EOP patients' antibody response against P. gingivalis infection does not differ significantly from that of AP patients. The person-to-person heterogeneous antibody production against P. gingivalis LPS could contribute to our understanding of the relationship between the defensive ability of EOP patients and their chronic infection with this pathogen.

Adolescent↗

PubMed2000

Social support for spouse caregivers of persons with dementia.

OBJECTIVES: This study analyzes the value of simultaneously taking helper and caregiver characteristics into account when examining social support received by spouse caregivers of persons with dementia. This study questions whether sources and types of received support vary by the gender and relationship of the helper and/or by the caregiver's race and gender. METHODS: Drawing on a sample of 210 spouse caregivers of persons with dementia, the Generalized Estimating Equation (GEE) method was used to estimate a population-average logistic regression model to address cross-level helper and caregiver interactions. RESULTS: Results indicate that helper and caregiver characteristics interact in complex ways. White male caregivers are more likely to receive emotional support from adult children and to receive practical assistance from formal sources compared with other types of support and to other race-gender caregiver groups. DISCUSSION: Description of social status characteristics of caregivers as determinants of their social network may be less fruitful in understanding the benefits of social support than a focus on which helpers assist with what kinds of task for which groups of caregivers.

Activities of Daily Living↗

PubMed2000

Precision of autokeratometry expressed as confidence ellipses in Euclidian 2-space.

A number of studies have examined the repeatability or precision of keratometers. All studies have found exceptionally high precision in keratometry of the spherically equivalent proportion, while the joint variation in astigmatic direction and magnitude barely has been explored. The purpose of this study was to examine the simultaneous variation in astigmatic direction and magnitude between two single autokeratometries, using a Nidek ARK 2000-S autokeratorefractometer. A single autokeratometry was performed on two occasions on 50 right eyes of patients with cataracts. The precision was defined as the paired difference between these two measurements. Each net astigmatism was transformed to polar values, and uni- and bivariate polar value analysis was performed. Precision of autokeratometry, expressed as a mean difference and a 95% confidence area, was calculated as a confidence ellipse in Euclidian 2-space. The accompanying net astigmatisms with confidence perimeters were derived by point-for-point transformation from polar values. Clinical variability may overwhelmingly be attributed to patient-related factors and only to a small degree to autokeratometry itself. Clinicians should know the precision of their keratometers, both for daily use and in the planning and dimensioning of scientific studies. Our results indicate that a minimum number of 25 eyes in each group is necessary in order to detect a difference of 0.25 diopters in surgically induced astigmatism between two surgical techniques. Precision of keratometry can only be determined from polar values or similar entities and never by the use of net astigmatisms.

Aged↗

PubMed2000

[The percentage of hepatitis B virus precore A83 mutant and its dynamicchange in fulminant hepatitis B].

OBJECTIVE: In order to clarify whether hepatitis B virus precore A83 mutant is related to the pathogenesis of fulminant hepatitis B or not. METHODS: The percentage of hepatitis B virus precore A83 mutant and the quantity of HBV DNA in sera from 9 patients with fulminant hepatitis B were assayed by the method of densitometry after mispairing PCR-restriction fragment length polymorphism (mpPCR-RFLP) and quantitative PCR, respectively. RESULTS: The HBV precore A83 mutant was found in sera of 6 out of 9 (66.7%) fulminant hepatitis patients while none of them were infected with the mutant strain alone, and all were mixed with wild strain. The percentage of the mutant over fifty percent is only in 2 cases in whom one was 59.3% (survival) and another 64.8% (died). The percentage below 31.0% was in 4 cases and all of them died. It was observed that appearance or disappearance of the A83 mutant and its dynamic change of percentage were consistent with the fluctuation of HBV DNA level but there was no correlation statistically (r=0.602, 0.583; P>0.05). CONCLUSION: The mutant strain alone has little correlation to the occurrence of fulminant hepatitis. It might be merely a accompaniment to follow the replication of HBV under the highly immune pressure.

Adolescent↗

PubMed2000

[The development of an extracting method for high frequency components of abnormal intra-QRS of exercise ECG signal].

This article introduces a method of extracting high frequency components of abnormal intra-QRS of exercise ECG signal by using spline function interpolation algorithm, and defines QRSe of the residual signal as quantitative index. Some expected results have been obtained. This method is an effective measuring approach to further researches on the high frequency components of exercise and other ECG signals.

Electrocardiography↗

PubMed2000

A trial of ademetionine in the treatment of intrahepatic biliary stasis viral hepatitis.

OBJECTIVE: To observe the efficacy and safety of ademetionine in the treatment of viral hepatitis with intrahepatic biliary stasis. METHODS: In this series, 110 patients with viral hepatitis associated intrahepatic biliary stasis were randomly divided into Groups A and B. Patients in Group A received ademetionine for four weeks. Patients in Group B received potassium magnesium aspartate for four weeks. RESULTS: In Group A, at the end of treatment, the effective rate for skin pruritus in patients with cholestatic hepatitis was 86.67% (13/15), and the effective rate for skin pruritus and anorexia were 88.24% (15/17) and 82.35% (14/17), respectively in patients with chronic hepatitis combining intrahepatic cholestasis, which were significantly higher than that in Group B (P<0.05). STB, SCB, TBA, ALT and AST were lower in Group A than Group B (P<0.05). The decrease of ALP and the increase of albumin after treatment were more significant in Group A than in Group B (P<0.05). CONCLUSION: Ademetionine has better efficacy than potassium magnesium aspartate in the treatment of patients with cholestatic viral hepatitis.

Adolescent↗

PubMed2000

[Effect of domestic glutathione on the alcoholic liver disease].

OBJECTIVE: To evaluate the effect and safety of domestic glutathione (GSH) on serum ALT, AST, SB levels in alcoholic liver disease (ALD) by multicenter, randomized and TAD controlled trial. METHODS: All the 110 patients with ALD enrolled had a history of drinking over 80g-120g daily for 5 years, and were randomized either into GSH (continuous infusion of 600g daily for 30d) or TAD (with the same dosage, course and route as GSH) group. The efficacy and safery were evaluated with clinical and biochemical (ALT, AST and GGT) parameters. RESULTS: After 8 weeks of treatment, the clinical signs were improved at a different degree in both groups. ALT, AST and SB showed no significant difference in the two groups (the efficacy rate of 93% vs 96%, P>0.05). CONCLUSION: The domestic GSH, with a good tolerance and safety, has a sound efficacy in the improvement of clinical signs and hepatic functions.

Adolescent↗

PubMed2000

[Effects of epimedium on the expression of interleukin-6 messenger ribonucleic acid in bone of ovariectomized rat].

OBJECTIVE: To investigate the effects of the traditional herb-epimedium on the expression of interleukin-6 (IL-6) mRNA in bone of ovariectomized rat. METHODS: Forty female rats were randomly allocated into 4 groups, 10 in each: ovariectomized (OVX) group, sham operation group, OVX followed by epimedium (group 3) or nilestriol (group 4) for 3 months respectively. All rats were then sacrificed, and total RNA were directly isolated from their right tibia. Interleukin-6 mRNA expression was detected by relative semiquantitative reverse transcription-polymerase chain reaction technique. Lumbar bone mineral density (BMD) was measured by dual-energy X ray absorptiometry before sacrifice. RESULTS: The BMD of epimedium group was significantly higher than that in the OVX group (P < 0.05). On the contrary, the IL-6 mRNA expression level of epimedium group was significantly lower than that in the OVX group (P < 0.01), but higher than those in the sham and nilestrial group (P < 0.01). CONCLUSIONS: IL-6 may play a role in the pathogenesis of postmenopausal teoporosis. Epimedium can inhibit the expression of IL-6 mRNA, which may contribute to its anti-resorptive effect.

Animals↗

PubMed2000

[Comparison of physiological characteristics of different ecotype plants].

Studies on the responses of photosynthesis, leaf water content and stoma resistance of 4 different ecotype plants to water stresses showed that their mechanism of drought-resistance was different. Mesic plants limited water loss from transpiration by increasing their stoma resistance, while xeric plants decreased water loss by keeping the high concentration of cell protoplasm. The latter had a higher efficiency of keeping water than the former. The leaf water content and stoma resistance was decreased from mesic to xeric plants, while the net photosynthetic rate per unit leaf was increased, indicating the difference of physiological characteristics among different ecotype plants.

Photosynthesis↗

PubMed2000

[Ordination analysis on relationship between bryophyte distribution and climatic factors].

Based on the data of climate and bryoflora in 21 mountainous regions of China, 61 moss families, 23 genera of Dicranaceae, 17 species of genus Campylopus and 35 species of genus Dicranum were analyzed by Canonical Correspond Analysis(CCA) and Detrended Canonical Correspond Analysis (DDCA) to reveal their distribution relationships with nine climatic factors, including annual average temperature, January average temperature, July average temperature, annual average rainfall, annual average fog days, annual average frost days and annual average light hours. The similarity of geographical elements among nine mountains in China and their relationships with climatic factors were also analyzed. The methods of applying DDCA and CCA to analyze the relationships between bryophyte and climatic factors were thus introduced. The studies indicate that CCA and DCCA are applicable in florology and phytogeography.

Bryopsida↗

PubMed2000

Retrospect on the research of the cultivation of Gastrodia elata Bl, a rare traditional Chinese medicine.

PURPOSE: To review the research on the cultivation of Gastrodia elata Bl, a rare traditional Chinese medicine. DATA SOURCES: The data come from our previous research and published review articles on G. elata cultivation. STUDY SELECTION: After reviewing the research results on G. elata from 1960 to 1995, we selected the core research on G. elata and a complete cultivation technique of rare traditional Chinese medicine G. elata. DATA EXTRACTION: Some important data were arranged in different tables, and new cultivation methods were reviewed. RESULTS: A. mellea has been found to have inhibiting effects on G. elata seed germination. The seeds are able to sprout only when a nutritional relationship exists between G. elata and a fungus of the same genus as M. osmundicola. The sprouted tubers have to set up a symbiotic relationship with A. mellea during their clone propagation period so as to grow normally. CONCLUSIONS: G. elata has to symbiosize with M. osmundicola and A. mellea so as to complete its life cycle from seed to seed. These findings have revealed the secret of the life cycle of G. elata that has been puzzling biological circles for years.

Drugs, Chinese Herbal↗

PubMed2000

[Transbronchial needle aspiration in routine bronchoscope practice].

OBJECTIVE: To evaluate the yield of transbronchial needle aspiration (TBNA) in a clinical routine bronscopy practice after training under the guide by CT scanning. METHODS: Using Wang TBNA System and CT scanning methods to define the site in airway for puncturing the enlarged mediastinal lymphnode. The positive rate of TBNA was 64%, almost equal to the positive rate (61%) of the method by operating directly under CT scanning. TBNA was performed on 100 consecutive patients with 152 enlarged mediastinal nodes undergoing diagnostic fiberoptic bronchoscopy. RESULT: The positive rate (64%) was equal to the positive rate (61%) under the CT guide. CONCLUSIONS: CT guiding TBNA is very useful for training doctors to learn the TBNA technique, and TBNA can be done very well and play an important role in routine bronchoscope practice.

Biopsy, Needle↗