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1.
Zhonghua Nei Ke Za Zhi ; 62(6): 705-710, 2023 Jun 01.
Article in Chinese | MEDLINE | ID: mdl-37263955

ABSTRACT

Objective: To investigate the misdiagnosis of area postrema syndrome (APS) manifesting as intractable nausea, vomiting and hiccups in neuromyelitis optic spectrum disease (NMOSD) and reduce the risk of misdiagnosis. Methods: We retrospectively analyzed data from NMOSD patients attending the Department of Neurology at the First Medical Center of PLA General Hospital between January 2019 and July 2021. SPSS25.0 was then used to analyze the manifestations, misdiagnosis, and mistreatment of APS. Results: A total of 207 patients with NMOSD were included, including 21 males and 186 females. The mean age of onset was 39±15 years (range: 5-72 years). The proportion of patients who were positive for serum aquaporin 4 antibody was 82.6% (171/207). In total, 35.7% (74/207) of the NMOSD patients experienced APS during the disease course; of these patients, 70.3% (52/74) had APS as the first symptom and 29.7% (22/74) had APS as a secondary symptom. The misdiagnosis rates for these conditions were 90.4% (47/52) and 50.0% (11/22), respectively. As the first symptom, 19.2% (10/52) of patients during APS presented only with intractable nausea, vomiting and hiccups; 80.8% (42/52) of patients experienced other neurological symptoms. The Departments of Gastroenterology and General Medicine were the departments that most frequently made the first diagnosis of APS, accounting for 54.1% and 17.6% of patients, respectively. The most common misdiagnoses related to diseases of the digestive system and the median duration of misdiagnosis was 37 days. Conclusions: APS is a common symptom of NMOSD and is associated with a high rate of misdiagnosis. Other concomitant symptoms often occur with APS. Gaining an increased awareness of this disease/syndrome, obtaining a detailed patient history, and performing physical examinations are essential if we are to reduce and avoid misdiagnosis.


Subject(s)
Hiccup , Neuromyelitis Optica , Male , Female , Humans , Child, Preschool , Child , Adolescent , Young Adult , Adult , Middle Aged , Aged , Neuromyelitis Optica/complications , Neuromyelitis Optica/diagnosis , Area Postrema , Retrospective Studies , Hiccup/etiology , Hiccup/complications , Vomiting/diagnosis , Vomiting/etiology , Nausea/diagnosis , Nausea/etiology , Inflammation , Syndrome , Autoantibodies , Diagnostic Errors , Aquaporin 4
3.
Zhonghua Jie He He Hu Xi Za Zhi ; 45(5): 519-524, 2022 May 12.
Article in Chinese | MEDLINE | ID: mdl-35527469

ABSTRACT

Bronchial asthma (asthma) is one of the most common chronic airway diseases, with more than 300 million people worldwide suffering from this disease. In recent years, studies have shown that compared with healthy people, the airway microecological structure and relative abundance of various flora of asthmatic patients have changed, and are related to the airway inflammatory phenotype of asthma. Airway microecology can affect the occurrence and development of asthma through immune response. The mechanism of interaction between airway microecology and asthma can provide new ideas for the accurate treatment of asthma. This article mainly reviewed the current research on airway microecology in asthma, and puts forward prospects for the accurate treatment of asthma in the future.


Subject(s)
Asthma , Microbiota , Humans , Immunity
5.
Zhonghua Yi Xue Za Zhi ; 99(36): 2831-2835, 2019 Sep 24.
Article in Chinese | MEDLINE | ID: mdl-31550811

ABSTRACT

Objective: To investigate the expression of Golgi phosphoprotein 3 (GOLPH3) in papillary thyroid carcinoma (PTC) and its relationship with clinicopathological characteristics of PTC and American Thyroid Association (ATA) risk of recurrence stratification. Methods: The mRNA expression level of GOLPH3 in PTC tissues and the matched adjacent noncancerous tissues from 30 cases of PTC undergoing surgical operation in Fujian Provincial Hospital between March 2017 and April 2018 was detected by reverse transcription-quantitative PCR (RT-qPCR). The protein expression of GOLPH3 in PTC tissues and the matched adjacent noncancerous tissues of 135 cases of PTC between January 2013 and April 2018 was measured by immunohistochemistry. The correlation between the expression of GOLPH3 in PTC and clinicopathologic characteristics and ATA risk of recurrence stratification was analyzed. Results: The mRNA level of GOLPH3 in PTC tissues was significantly higher than that in adjacent noncancerous tissues (7.53±1.32 vs 3.64±1.44, P<0.001). The protein expression level of GOLPH3 in PTC tissues was significantly higher than that in adjacent noncancerous tissues [66(30, 95) vs 34(20, 72), P<0.001]. The expression of GOLPH3 was significantly correlated to the tumor size (P=0.026), extrathyroid invasion (P=0.016), lymph node metastasis (P=0.001) and TNM stage (P=0.027) in PTC. Multivariate logistic regression analysis showed that GOLPH3 expression was independently correlated to tumor size (OR=3.58, 95%CI: 1.19-15.46, P=0.017) and lymph node metastasis (OR=7.28, 95%CI: 2.43-10.08, P=0.002). The expression of GOLPH3 was positively correlated to ATA risk of recurrence stratification (P=0.041). Conclusions: Overexpression of GOLPH3 is associated with the development of PTC and poor prognosis in patients with PTC. Detection of GOLPH3 expression can help evaluate proliferative and metastatic potential of PTC, as well as the risk of postoperative recurrence in patients with PTC.


Subject(s)
Membrane Proteins/genetics , Thyroid Cancer, Papillary , Thyroid Neoplasms , Humans , Lymphatic Metastasis , Neoplasm Recurrence, Local , Phosphoproteins , Prognosis , Thyroid Cancer, Papillary/genetics , Thyroid Neoplasms/genetics
6.
Article in Chinese | MEDLINE | ID: mdl-30550138

ABSTRACT

Summary Two patients both complained of one year history of hoarseness and the clinical manifestations and imageology among 2 patients were lack of specificity. The pathological tissue was successfully eradicated by surgical removal. Histopathology established laryngeal malignant melanoma as the diagnosis. The clinical manifestations and imageology were lack specificity between laryngeal malignant melanoma, laryngeal cancer and other malignant tumor, the diagnosis is difficult, often confirmed by postoperative pathology, the treatment is often by surgery and have a poor prognosis.

7.
Genet Mol Res ; 13(3): 6202-12, 2014 Aug 15.
Article in English | MEDLINE | ID: mdl-25158247

ABSTRACT

This study aimed to investigate the prevalence and treatment gaps of epilepsy, as well as the clinical effects, drug safety, and retention rates of sodium valproate (VPA) for treating epilepsy. Physicians received supervised training to use the survey form recommended by the Chinese Association Against Epilepsy while screening for suspected or confirmed epilepsy cases. These cases were ultimately enrolled in the study by neurologists. Enrolled patients were given a year of free VPA treatment so that its efficacy and adverse effects during the follow-up period could be evaluated. In total, 302 patients were enrolled in this study, which included 189 males and 113 females. Among these cases, 179 (59.27%) were confirmed to have generalized seizures, 162 (53.6%) had tonic-clonic seizures, 10 (3.3%) had absence seizures, and 123 (40.72%) had partial seizures. Only 63 patients had received regular treatments 1 week before enrollment, with a treatment gap of 79.1%. The retention rates during the 6th, 12th, 18th, and 24th months were 100, 93.56, 89.05, and 77.06%, respectively. During the 1-year follow-up period, 30 cases encountered mild adverse effects, but no severe adverse reactions were reported. A large treatment gap for epilepsy still existed in the rural areas of southern China, with few adverse effects and high retention rates. VPA showed satisfactory effects in the treatment of epileptic patients.


Subject(s)
Anticonvulsants/therapeutic use , Epilepsies, Partial/drug therapy , Epilepsy, Absence/drug therapy , Seizures/drug therapy , Time-to-Treatment/statistics & numerical data , Valproic Acid/therapeutic use , Adolescent , Adult , Aged , Child , China , Epilepsies, Partial/diagnosis , Epilepsies, Partial/physiopathology , Epilepsy, Absence/diagnosis , Epilepsy, Absence/physiopathology , Female , Health Care Surveys , Humans , Male , Middle Aged , Patient Compliance , Rural Population , Seizures/diagnosis , Seizures/physiopathology , Treatment Outcome
8.
Cryo Letters ; 34(4): 381-7, 2013.
Article in English | MEDLINE | ID: mdl-23995405

ABSTRACT

The metabolic function of cryopreserved cells, in addition to cell viability after thawing, is an important parameter in any successful cryopreservation protocol. Dimethyl sulfoxide (Me2SO) is known to affect the differentiation of recovered cells. In this study, we report that sugars and sugar alcohols increases cell recovery, and also improves the metabolic function of human hepatocytes that are cryopreserved using low concentration Me2SO (5%). Three sugars (glucose, sucrose, and trehalose) and three sugar alcohols (xylitol, maltol, and sorbitol) have been tested. Cell viability after thaw and 24-h post-thaw attachment rate of cryopreserved human hepatocytes were assessed. Post-thaw metabolic activities (albumin, glucose, urea content) were measured, and cell proliferation was observed with inverted microscope. Cell viability, post-thaw attachment rate and metabolic activity of cryopreserved hepatocytes are enhanced by the addition of 0.4M sorbitol into 5% Me2SO solution. The study concludes that 5% Me2SO + 0.4M sorbitol can replace the 10% Me2SO method for cryopreservation of human hepatocytes at -80C freezer. The new solution may reduce the side effects on the patients and improve the safety of using cryopreserved hepatocytes.


Subject(s)
Cryopreservation/methods , Cryoprotective Agents/metabolism , Dimethyl Sulfoxide/metabolism , Hepatocytes/cytology , Cell Line , Cell Proliferation/drug effects , Cell Survival/drug effects , Glucose/metabolism , Hepatocytes/drug effects , Hepatocytes/metabolism , Humans , Pyrones/metabolism , Sorbitol/metabolism , Sucrose/metabolism , Trehalose/metabolism , Xylitol/metabolism
9.
J Enzyme Inhib ; 16(3): 269-74, 2001.
Article in English | MEDLINE | ID: mdl-11697047

ABSTRACT

Glycosylasparaginase catalyzes the hydrolysis of the N-glycosylic bond between asparagine and N-acetylglucosamine in the catabolism of N-linked glycoproteins. Previously only three competitive inhibitors, one noncompetitive inhibitor, and one irreversible inhibitor of glycosylasparaginase activity had been reported. Using human glycosylasparaginase from human amniotic fluid, L-aspartic acid and four of its analogues, where the alpha-amino group was substituted with a chloro, bromo, methyl or hydrogen, were competitive inhibitors having Ki values between 0.6-7.7 mM. These results provide supporting evidence for a proposed intramolecular autoproteolytic activation reaction. A proposed phosphono transition state mimic and a sulfo transition state mimic were competitive inhibitors with Ki values 0.9 mM and 1.4 mM, respectively. These results support a mechanism for the enzyme-catalyzed reaction involving formation of a tetrahedral high-energy intermediate. Three analogues of the natural substrate were noncompetitive inhibitors with Ki values between 0.56-0.75 mM, indicating the presence of a second binding site that may recognize (substituted)acetamido groups.


Subject(s)
Aspartic Acid/metabolism , Aspartylglucosylaminase/antagonists & inhibitors , Aspartylglucosylaminase/metabolism , Enzyme Inhibitors/metabolism , Acetylglucosamine/analogs & derivatives , Acetylglucosamine/chemistry , Acetylglucosamine/metabolism , Aspartic Acid/analogs & derivatives , Aspartic Acid/chemistry , Cysteine/chemistry , Cysteine/metabolism , Enzyme Inhibitors/pharmacology , Humans , Molecular Structure , Propionates/chemistry , Propionates/metabolism , Serine Endopeptidases/chemistry , Serine Endopeptidases/metabolism
10.
Proc Natl Acad Sci U S A ; 98(17): 9730-5, 2001 Aug 14.
Article in English | MEDLINE | ID: mdl-11493709

ABSTRACT

Deacetylation of the N-terminal tails of core histones plays a crucial role in gene silencing. Rpd3 and Hda1 represent two major types of genes encoding trichostatin A-sensitive histone deacetylases. Although they have been widely found, their cellular and developmental roles remain to be elucidated in metazoa. We show that Drosophila Hdac1, an Rpd3-type gene, interacts cooperatively with Polycomb group repressors in silencing the homeotic genes that are essential for axial patterning of body segments. The biochemical copurification and cytological colocalization of HDAC1 and Polycomb group repressors strongly suggest that HDAC1 is a component of the silencing complex for chromatin modification on specific regulatory regions of homeotic genes.


Subject(s)
DNA-Binding Proteins , Drosophila Proteins , Drosophila melanogaster/genetics , Gene Silencing , Genes, Homeobox , Genes, Insect , Histone Deacetylases/physiology , Insect Proteins/physiology , Animals , Chromosome Mapping , Drosophila melanogaster/embryology , Drosophila melanogaster/metabolism , Genes, Homeobox/genetics , Histone Deacetylase 1 , Histone Deacetylase 2 , Histones/metabolism , Insect Proteins/genetics , Insect Proteins/metabolism , Macromolecular Substances , Morphogenesis , Multigene Family , Polycomb Repressive Complex 1 , Repressor Proteins/physiology
11.
Arch Biochem Biophys ; 391(2): 165-70, 2001 Jul 15.
Article in English | MEDLINE | ID: mdl-11437347

ABSTRACT

Glycosylasparaginase catalyzes the hydrolysis of the N-glycosylic bond in N(4)-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-L-asparagine in the catabolism of N-linked oligosaccharides. A deficiency, or absence, of enzyme activity gives rise to aspartylglycosaminuria, the most common disorder of glycoprotein metabolism. The enzyme catalyzes the hydrolysis of a variety of asparagine and aspartyl compounds containing a free alpha-carboxyl group and a free alpha-amino group; computational studies suggest that the alpha-amino group actively participates in the catalytic mechanism. In order to study the importance of the alpha-carboxyl group and the alpha-amino group on the natural substrate to the reaction catalyzed by the enzyme, 14 analogues of the natural substrate were studied where the structure of the aspartyl group of the substrate was changed. The incremental binding energy (DeltaDeltaGb) for those analogues that were substrates was calculated. The results show that the alpha-amino group may be substituted with a group of comparable size, for the alpha-amino group contributes little, if any, to the transition state binding energy of the natural substrate. The alpha-amino group position acts as an "anchor" in the binding site for the substrate. On the other hand, the alpha-carboxyl group is necessary for enzyme activity; removal of the alpha-carboxyl group or changing it to an alpha-carboxamide group results in no hydrolysis reaction. Also, N-acetyl-D-glucosamine is not sufficient for binding to the active site for efficient hydrolysis by the enzyme. These results provide supporting evidence for a proposed intramolecular autoproteolytic activation reaction for the enzyme. However, the results raise a question as to an important role for the alpha-amino group in the catalytic mechanism as indicated in computational studies.


Subject(s)
Acetylglucosamine/analogs & derivatives , Asparagine/metabolism , Aspartylglucosylaminase/metabolism , Glucose/metabolism , Asparagine/analogs & derivatives , Asparagine/chemistry , Glucose/analogs & derivatives , Glucose/chemistry , Humans , Hydrolysis , Peptide Hydrolases/metabolism , Statistics as Topic , Substrate Specificity
12.
Phys Rev Lett ; 86(6): 954-7, 2001 Feb 05.
Article in English | MEDLINE | ID: mdl-11177983

ABSTRACT

There is increasing evidence that conventional cold dark matter (CDM) models lead to conflicts between observations and numerical simulations of dark matter halos on subgalactic scales, which rules out the favored candidates for CDM, namely weakly interacting massive particles (WIMPs). We propose a mechanism of nonthermal production of WIMPs and study its implications on the power spectrum. Our results show that, in this context, WIMPs as candidates for dark matter can work well both on large scales and on subgalactic scales.

13.
Biochemistry ; 39(40): 12457-64, 2000 Oct 10.
Article in English | MEDLINE | ID: mdl-11015227

ABSTRACT

The formation of a DNA "paper-clip" type triple helix (triplex) with a common sequence 5'-d-(TC)(3)T(a)()(CT)(3)C(b)()(AG)(3) (a and b = 0-4) was studied by UV thermal melting experiments and CD spectra. These DNA oligomers form triplexes and duplexes under slightly acidic and neutral conditions, respectively. The stability of the formed triplexes (at pH 4.5) or duplexes (at pH 7.0 or 8.0) does not vary significantly with the size of the loops (a and b = 1-4). At pH 6.0, the triplex stability is, however, a function of a and b. It is also interesting to note that the oligomer 5'-d-(TC)(3)(CT)(3)(AG)(3) (a and b = 0) forms a stable triplex at pH 4.5 with a slightly lower T(m) value, due to dissociation of a base triad at one end and a distorted base triad at the other, observed by (1)H NMR. Thus, we have here a model system, 5'-d-(TC)(3)T(a)(CT)(3)C(b)(AG)(3), that could form a triplex effectively with (a and b = 1-4) and without (a and b = 0) loops under acidic conditions. In addition, the triplex formation of oligomers with replacement of one, two, or three 2'-deoxycytidine in the Hoogsteen strand by either 2'-deoxypseudoisocytidine (D) or 2'-O-methylpseudoisocytidine (M) was also studied in the sequence 5'-d-(TX)(3)T(2)(CT)(3)C(2)(AG)(3) (where X is C, D, or M). Both CD spectra and UV melting results showed that only D3 [(TX)(3) = (TD)(3)] and M3 [(TX)(3) = (TM)(3)] were able to form the paper-clip structure under both neutral and acidic conditions. This is because the N(3)H of a pseudoisocytosine base can serve as a proton donor without protonation. We hereby proved that the 2'-deoxypseudoisocytidine, similar to 2'-O-methylpseudoisocytidine, could replace 2'-deoxycytidine in the Hoogsteen strand to provide triplex formation at neutral pH.


Subject(s)
Cytidine/chemistry , Cytosine/analogs & derivatives , DNA/chemistry , Nucleic Acid Conformation , Adenine , Base Composition , Base Pairing , Base Sequence , Cytidine/chemical synthesis , Cytosine/chemistry , Guanine , Magnesium Chloride/chemistry , Nucleic Acid Denaturation , Oligodeoxyribonucleotides/chemistry , Protons , Thermodynamics , Thionucleotides/chemical synthesis , Thymine
14.
Cancer ; 86(9): 1712-9, 1999 Nov 01.
Article in English | MEDLINE | ID: mdl-10547543

ABSTRACT

BACKGROUND: Plasma transforming growth factor-beta1 (TGFbeta1) levels are increased in many malignancies at the time of diagnosis, including all forms of lung carcinoma. Therefore, the potential use of TGFbeta1 as a plasma marker to predict the long term outcome of lung carcinoma patients treated with radiotherapy (RT) was evaluated. METHODS: Plasma samples for 59 newly diagnosed lung carcinoma patients were assayed for TGFbeta1 before RT (pre RT), at the end of RT (end RT), and during follow-up after RT. TGFbeta1 was extracted from plasma using an acid-ethanol method. An enzyme-linked immunoadsorbent assay was used to quantify the plasma TGFbeta1 levels. The normal value for this assay is < or =7.5 ng/mL. Disease status at last follow-up was without knowledge of TGFbeta1 levels. Comparisons within groups and between groups were estimated using analysis of variance and the Student t test for unpaired data, respectively. RESULTS: The 59 patients were divided into 2 groups according to their disease status at last follow-up: those with no evidence of disease (NED) (n = 13) and those with disease (WD) (n = 46). The median follow up was 26.8 months and 12.4 months, respectively, for the NED and WD groups. No significant differences were found in the clinical characteristics between the two groups. The plasma TGFbeta1 level before RT was significantly higher in the WD group (mean +/- standard error of the mean [SEM] = 12.5+/-1.7 ng/mL; median = 8.6 ng/mL) compared with the NED group (mean +/- SEM = 6.0+/-1.0 ng/mL; median = 6.0 ng/mL) (P = 0.037). At the time of last follow-up, WD patients had a significantly higher plasma TGFbeta1 level (mean +/- SEM = 11.6+/-1.3 ng/mL; median = 9.6 ng/mL) compared with NED patients (mean +/- SEM = 3.7+/-0.5 ng/mL; median = 3.6 ng/mL) (P = 0.002). CONCLUSIONS: These data demonstrate that plasma TGFbeta1 may be a useful tumor marker in patients with lung carcinoma.


Subject(s)
Lung Neoplasms/blood , Lung Neoplasms/radiotherapy , Transforming Growth Factor beta/blood , Adenocarcinoma/blood , Adenocarcinoma/diagnosis , Adenocarcinoma/radiotherapy , Aged , Biomarkers, Tumor/blood , Carcinoma, Large Cell/blood , Carcinoma, Large Cell/diagnosis , Carcinoma, Large Cell/radiotherapy , Carcinoma, Non-Small-Cell Lung/blood , Carcinoma, Non-Small-Cell Lung/diagnosis , Carcinoma, Non-Small-Cell Lung/radiotherapy , Carcinoma, Small Cell/blood , Carcinoma, Small Cell/diagnosis , Carcinoma, Small Cell/radiotherapy , Carcinoma, Squamous Cell/blood , Carcinoma, Squamous Cell/diagnosis , Carcinoma, Squamous Cell/radiotherapy , Case-Control Studies , Disease-Free Survival , Female , Humans , Immunohistochemistry , Lung Neoplasms/diagnosis , Male , Middle Aged , Prognosis
15.
Protein Sci ; 8(2): 410-7, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10048334

ABSTRACT

The serine protease subtilisin BPN' is a useful catalyst for peptide synthesis when dissolved in high concentrations of a water-miscible organic co-solvent such as N,N-dimethylformamide (DMF). However, in 50% DMF, the k(cat) for amide hydrolysis is two orders of magnitude lower than in aqueous solution. Surprisingly, the k(cat) for ester hydrolysis is unchanged in 50% DMF. To explain this alteration in activity, the structure of subtilisin 8397+1 was determined in 20, 35, and 50% (v/v) DMF to 1.8 A resolution. In 50% DMF, the imidazole ring of His64, the central residue of the catalytic triad, has rotated approximately 180 degrees around the Cbeta-Cgamma bond. Two new water molecules in the active site stabilize the rotated conformation. This rotation places His64 in an unfavorable geometry to interact with the other members of the catalytic triad, Ser221 and Asp32. NMR experiments confirm that the characteristic resonance due to the low barrier hydrogen bond between the His64 and Asp32 is absent in 50% DMF. These experiments provide a clear structural basis for the change in activity of serine proteases in organic co-solvents.


Subject(s)
Subtilisins/chemistry , Crystallography, X-Ray , Dimethylformamide/pharmacology , Dose-Response Relationship, Drug , Histidine/analysis , Magnetic Resonance Spectroscopy , Models, Chemical , Models, Molecular , Mutagenesis, Site-Directed , Protein Conformation , Thermodynamics
16.
Article in Chinese | MEDLINE | ID: mdl-12080776

ABSTRACT

OBJECTIVE: In order to increase the survival area of pedicled fasciocutaneous flap, a multiple pedicled blocking randomized fasciocutaneous flap was designed. METHODS: From January 1991 to September 1998, this technique was used to repair 33 cases, including 27 males and 6 females and the ages ranged from 6 to 58 years. All of the patients were suffered from traffic accidents. In these cases, 22 cases had skin defects of legs and feet with bone, nerve and tendon exposed, 5 cases had osteomyelitis as well as internal fixaters exposed and the other 6 had deformity from scar. The size of the flap was 25.0 cm x 13.0 cm x 2.4 cm at its maximum and 6.0 cm x 3.5 cm x 1.5 cm at its minimum. Based on the traditional blocking flap, according to the severity of the wound and conditions of the neighboring tissues, a flap having 2 to 4 orthogonal pedicles with a width of 1.5 to 3.0 cm was designed. The medical-graded stainless steel sheet was implanted below the deep fascia, and after blocking for 3 to 6 days, the side pedicles were divided. 6 to 14 days later, one of the two remaining pedicles was divided and was transferred to repair the defect. RESULTS: 31 cases were followed up for 6 months to 5 years without any trouble of the joints. The flap had a good external appearance and was high pressure-resistant. CONCLUSION: The multiple pedicled blocking randomized fasciocutaneous flap increased the size of the flap and the length to width ratio. It had the following advantages: manage at will, high resistance to infection and a large survival area of flap.


Subject(s)
Dermatologic Surgical Procedures , Foot Injuries/surgery , Leg Injuries/surgery , Surgical Flaps , Accidents, Traffic , Adolescent , Adult , Child , Female , Follow-Up Studies , Graft Survival , Humans , Male , Middle Aged
17.
Mol Cell Biol ; 15(12): 6601-12, 1995 Dec.
Article in English | MEDLINE | ID: mdl-8524225

ABSTRACT

Maintenance of the "on-off" state of Drosophila homeotic genes in Antennapedia and bithorax complexes requires activities of the trithorax and Polycomb groups of genes. To identify cis-acting sequences for functional reconstruction of regulation by both trithorax and Polycomb, we examined the expression patterns of several Ubx-lacZ transgenes that carry upstream fragments corresponding to a region of approximately 50 kb. A 14.5-kb fragment from the postbithorax/bithoraxoid region of Ultrabithorax exhibited proper regulation by both trithorax and Polycomb in the embryonic central nervous system. Using a Drosophila haploid cell line for transient expression, we found that trithorax or Polycomb can function independently through this upstream fragment to activate or repress the Ultrabithorax promoter, respectively. Studies of deletion mutants of trithorax and Polycomb demonstrated that trithorax-dependent activation requires the central zinc-binding domain, while Polycomb-dependent repression requires the intact chromodomain. In addition, trithorax-dependent activity can be abrogated by increasing the amount of Polycomb, suggesting a competitive interaction between the products of trithorax and Polycomb. Deletion analysis of this fragment demonstrated that a 440-bp fragment contains response elements for both trithorax and Polycomb. Furthermore, we showed that the integrity of the proximal promoter region is essential for trithorax-dependent activation, implicating a long-range interaction for promoter activation.


Subject(s)
DNA-Binding Proteins/biosynthesis , Drosophila Proteins , Drosophila melanogaster/genetics , Gene Expression Regulation , Genes, Homeobox , Promoter Regions, Genetic , Protein Biosynthesis , Regulatory Sequences, Nucleic Acid , Transcription Factors , Animals , Animals, Genetically Modified , Base Sequence , DNA Primers , DNA-Binding Proteins/genetics , Drosophila melanogaster/physiology , Embryo, Nonmammalian/physiology , Gene Expression , Insect Hormones/biosynthesis , Molecular Sequence Data , Polycomb Repressive Complex 1 , Polymerase Chain Reaction , Proteins/genetics , Transcriptional Activation , beta-Galactosidase/biosynthesis , beta-Galactosidase/genetics
18.
Sci China B ; 36(9): 1069-81, 1993 Sep.
Article in English | MEDLINE | ID: mdl-8274201

ABSTRACT

The crystallographic refinement of trichosanthin has been performed at 2.6 A resolution. The crystal and molecular structure of trichosanthin is described in detail in this paper. On summarizing the regularity of the amino acid sequences of eight kinds of ribosome inactivating proteins and combining with the crystal and molecular structure of trichosanthin, fifteen most conservative amino acid residues are analyzed. It is found that four most conservative polar amino acid residues Gln156, Glu160, Arg163 and Glu189 gather on the molecular surface on the boundary of the large and small domains, thus forming the active center of the protein molecule.


Subject(s)
Protein Structure, Secondary , Trichosanthin/chemistry , Amino Acid Sequence , Crystallography , Molecular Conformation , Molecular Sequence Data , Molecular Structure
19.
J Biomol Struct Dyn ; 8(5): 911-33, 1991 Apr.
Article in English | MEDLINE | ID: mdl-1652260

ABSTRACT

Triplex and duplex formation of two deoxyribohexadecamers d-A-(G-A)-G (a) and d-C-(T-C)-T (b) have been studied by UV, CD, fluorescence, and proton NMR spectroscopy. Optical studies of a and b at dilute concentrations (microM range) yielded results similar to those seen for polymers of the same sequence, indicating that these hexadecamers have properties similar to the polymers in regard to triplex formation. The CD spectra of concentrated NMR samples (mM range) are similar to those observed at optical concentrations at both low and high pH, making possible a correlation between CD and NMR studies. In NMR spectra, two imido NH-N hydrogen bonded resonance envelopes at 12.6 and 13.7 ppm indicate that only the duplex conformation is present at pH greater than 7.7. Four new NH-N hydrogen-bonded resonance envelopes at 12.7, 13.5, 14.2, and 14.9 ppm are observed under acidic conditions (pH 5.6) and the two original NH-N resonances gradually disappear as the pH is lowered. Assignment of these four peaks to Watson-Crick G.C. Hoogsteen T.A Watson-Crick A.T, and Hoogsteen C+.G hydrogen-bonded imidos, respectively, confirm the formation of triple-stranded DNA NMR results also show that triplex is more stable than duplex at the same salt condition and that triplex melts to single strands directly without going through a duplex intermediate. However, in the melting studies, a structural change within the triple-stranded complex is evident at temperatures significantly below the major helix-to-coil transition. These studies demonstrate the feasibility of using NMR spectroscopy and oligonucleotide model compounds a and b for the study of DNA triplex formation.


Subject(s)
DNA/chemistry , Deoxyribonucleotides/chemistry , Circular Dichroism , Hydrogen Bonding , Hydrogen-Ion Concentration , Magnetic Resonance Spectroscopy , Nucleic Acid Denaturation , Protons , Spectrometry, Fluorescence , Spectrophotometry, Ultraviolet , Temperature
20.
Carbohydr Res ; 210: 247-54, 1991 Mar 20.
Article in English | MEDLINE | ID: mdl-1715236

ABSTRACT

The structure of the type-specific polysaccharide antigen of Streptococcus rattus was determined by methylation analysis, periodate oxidation, and by 2D-1H- and 13C-n.m.r.-spectroscopy. The polysaccharide was found to possess the trisaccharide repeating unit----3)-alpha-L-Rhap-(1----2)-[alpha-D-Galp-(1----3)]-alpha-L-+ ++Rhap- (1----.


Subject(s)
Polysaccharides, Bacterial/chemistry , Streptococcus/immunology , Carbohydrate Sequence , Epitopes/immunology , Magnetic Resonance Spectroscopy , Methylation , Molecular Sequence Data , Molecular Structure , Oxidation-Reduction , Periodic Acid , Polysaccharides, Bacterial/isolation & purification
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