RESUMO
Hepatitis B virus (HBV) infection is an important public health concern, as approximately 3.5% of the world's population is currently chronically infected. Chronic HBV infection is the primary cause of cirrhosis, hepatocellular carcinoma, and deaths related to liver disease globally. Studies have found that in HBV infection, viruses can directly or indirectly regulate mitochondrial energy metabolism, oxidative stress, respiratory chain metabolites, and autophagy, thereby altering macrophage activation status, differentiation types, and related cytokine secretion type and quantity regulations. Therefore, mitochondria have become an important signal source for macrophages to participate in the body's immune system during HBV infection, providing a basis for mitochondria to be considered as a potential therapeutic target for chronic hepatitis B.
Assuntos
Hepatite B Crônica , Hepatite B , Neoplasias Hepáticas , Humanos , Vírus da Hepatite B/fisiologia , Hepatite B/complicações , Hepatite B Crônica/complicações , Mitocôndrias , MacrófagosRESUMO
Objective: To investigate the clinical features in patients with iridocorneal endothelial (ICE) syndrome. Methods: A retrospective case series study. Data of clinical manifestations of patients with ICE syndrome including clinical subtypes, presenting visual acuity, clinical features and secondary glaucoma were collected from January 2014 to May 2020 in the Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University. The Wald's Chi-square test of generalized estimating equations was performed to analyze the differences in three clinical subtypes. Results: A total of 127 eyes of 114 subjects (64 females and 50 males) were included. Mean±SD age at presentation was (49±13) years. There were 53 patients (46.5%) with Chandler's syndrome (CS), 36 patients (31.6%) with progressive iris atrophy (PIA), 24 patients (21.0%) with Cogan-Reese syndrome (CRS) and one patient (0.9%) with an undetermined subtype. And 101 patients (88.6%) had uniocular ICE syndrome. Approximately 81.7% (49/60), 56.1% (23/41) and 41.7% (10/24) of eyes presented visual acuity <0.3 in patients with CS, PIA and CRS, respectively. Corneal edema was most common in CS (52.5%, 32/61), followed by PIA (29.3%, 12/41) and CRS (20.8%, 5/24). Corectopia was found in 95.8% (23/24) of eyes with CRS, 95.1% (39/41) of eyes with PIA and 78.7% (48/61) of eyes with CS. Polycoria was observed in 29.3% (12/41) of eyes with PIA, 3.3% (2/61) of eyes with CS and 8.3% (2/24) of eyes with CRS. Ectropion uvea was most common in CRS (54.2%, 13/24), followed by 16.4% (10/61) in CS and 12.2% (5/41) in PIA. Glaucoma was found in 94 eyes (74.0%, 94/127). Among them, 60.7% (37/61) of CS, 80.5% (33/41) of PIA and 95.8% (23/24) of CRS had secondary glaucoma. The difference of presenting visual acuity, corneal edema, corectopia, polycoria, ectropion uveae and secondary glaucoma in three clinical subtypes all had statistical significance (Wald χ2=13.87, 10.77, 965.78, 11.45, 15.00, 222.04; all P<0.05). And 86.2% of eyes (81/94) had glaucoma surgeries and 41 eyes (43.6%, 41/94) had the intraocular pressure well controlled with various interventions. Conclusions: ICE syndrome is mostly uniocular and more common in middle-aged patients. CS is the most common clinical subtype with poor presenting visual acuity. About 3/4 of eyes have secondary glaucoma, and the majority of them require surgical interventions, but prognoses are discouraging.
Assuntos
Glaucoma , Síndrome Endotelial Iridocorneana , Doenças da Íris , Endotélio Corneano , Feminino , Humanos , Pressão Intraocular , Masculino , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
OBJECTIVE: To observe the effect on renal function from increased intra-abdominal pressure. PATIENTS AND METHODS: Sixty patients with abdominal compartment syndrome (ACS) were included in this study. Intra-abdominal pressure, mean arterial pressure (MAP) and central venous pressure (CVP) were recorded three times per day at a fixed time. Meanwhile, blood samples were collected for serum creatinine measurement and urine volume per hour was recorded. RESULTS: The urine volume gradually decreased with the increasing intra-abdominal pressure, from 92. 6 ± 20 ml/h to 27.9 ± 20 ml/h (p < 0. 05), and the serum creatinine increased from 68.4 ± 39.9 mol/L to 249.4 ± 111.5 mol/L (p < 0. 05). The CVP increased from 0.98 ± 0.19 kPa to 1.56 ± 0.31 kPa with the increase or decrease of the MAP. The increase in intra-abdominal pressure was negatively related to the urine volume (r = -0.193, p < 0.05), and positively related to the serum creatinine (r = 0.162, p < 0.05), but not related to the MAP. CONCLUSIONS: The increase of intra-abdominal pressure, was closely related to oliguria and increasing serum creatinine. The use of fluid resuscitation and diuretics had few effects on the recovery of the renal function. When the intra-abdominal pressure had decreased, the urine volume increased, and the serum creatinine decreased.
Assuntos
Hipertensão Intra-Abdominal/diagnóstico , Hipertensão Intra-Abdominal/epidemiologia , Rim/fisiologia , Adolescente , Adulto , Idoso , Feminino , Humanos , Hipertensão Intra-Abdominal/fisiopatologia , Rim/fisiopatologia , Testes de Função Renal , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
The macrophages mediated biodegradation of two biomaterials, collagen/hydroxylapatite (CHA) and beta-tricalcium phosphate ceramics (TCP), was studied in 24 male Kunming mice and 20 male C57BL/6 mice with histopathologic, histochemical and ultrastructural observation. It was demonstrated that macrophages infiltrated after CHA, TCP were implanted. The macrophages could be differentiated from fibroblasts and the other infiltrated cells for special cellular profile and strong acid phosphatase activity. Morphologically, monocyte-macrophages and infused multinuclear giant cell degraded CHA and TCP by phagocytosis and extracellular resorption. The carbonic anhydrase activity of macrophages was demonstrated by histochemical technique. It suggested that macrophages secreted H+ and accomplished the decalcification of calcium phosphate compound of CHA and TCP. We conclude that macrophages are the main mediating cells which degraded CHA and TCP intracellularly and extracellularly.
Assuntos
Materiais Biocompatíveis , Fosfatos de Cálcio , Durapatita , Macrófagos/metabolismo , Próteses e Implantes , Animais , Cerâmica , Colágeno , Masculino , Camundongos , Camundongos Endogâmicos C57BL , FagocitoseRESUMO
OBJECTIVE: To investigate the effect of transforming growth factor (TGF) beta 1 gene transfection on the growth of mesenchymal stem cells(MSCs) and to evaluate a new biomimetic biodegradable polymer as scaffolds for applications in articular cartilage tissue engineering. METHODS: Principles of tissue engineering were combined organically with principles of gene therapy to produce cultured periosteum-derived MSCs transduced with the full-length rat TGF-beta 1 cDNA in vitro. These cells were then seeded onto three-dimensional porous poly-DL-lactide scaffolds modified with poly-L-lysine that mimicked cell-binding domains found on natural extracellular matrix to promote specific cell adhesion. The adhesion, proliferation, and differentiation of the transfected MSCs were examined with scanning electron microscope within 2 weeks. RESULTS: All cells adhered to the biomimetic matrices well, but more cartilage-like tissue was formed for TGF-beta 1 gene modified MSCs/scaffolds composites than for the control groups. Transfer of gene encoding TGF-beta 1 to MSCs promoted its proliferation and differentiation significantly. CONCLUSIONS: The TGF-beta 1 gene transduced MSCs/biomimetic matrix composites used in this study was the first attempt to apply the principles of molecular tissue engineering for articular cartilage repair. This new molecular tissue engineering approach could be of potential benefit to repair damaged articular cartilage, especially in osteoarthritis. The new biomimetic biodegradable polymer matrices modified with biomolecules not only have good structural compatibility, but also have better interfacial compatibility and bioactivity, and can be used as scaffolds for articular cartilage tissue engineering.
Assuntos
Materiais Biocompatíveis , Polímeros , Células-Tronco/citologia , Engenharia Tecidual/métodos , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/farmacologia , Animais , Adesão Celular , Técnicas de Cultura de Células/métodos , Diferenciação Celular , Divisão Celular , Ácido Láctico , Mesoderma/citologia , Coelhos , TransfecçãoRESUMO
Confluent cultures of primary hamster tracheal surface epithelial (HTSE) cells grown on a thick collagen gel are highly enriched with secretory cells and constitutively release mucins. In the present experiment, we examined the possible effect of mechanical strain of cultured HTSE cells on the release of mucin. The mechanical strain of cells was accomplished by several methods: 1) by floating the gel from the culture dish by rimming; 2) by treatment with EGTA which interrupts intercellular tight junctions; 3) by treatment with collagenase which disrupts the cell-matrix adhesion; and 4) by mechanically flexing the collagen gel matrix. All these conditions caused increases of mucin release without damage on the plasma membrane. We conclude that a number of mechanical strains which might alter cell shape can stimulate mucin release from cultured HTSE cells. Such a mechanism might be operative in the physiological regulation of airway goblet cell mucin secretion where mechanical strains may be induced on epithelial cells by underlying smooth muscles.
Assuntos
Colágeno , Técnicas Citológicas , Mucinas/metabolismo , Traqueia/metabolismo , Animais , Células Cultivadas , Colagenases/farmacologia , Ácido Egtázico/farmacologia , Células Epiteliais , Epitélio/metabolismo , Epitélio/ultraestrutura , Géis , Microscopia Eletrônica , Traqueia/citologia , Traqueia/ultraestruturaRESUMO
OBJECTIVE: To determine whether endoscopes serve as a reservoir for Helicobacter pylori and whether two commonly used cleaning and disinfection methods eliminate the risk of H. pylori transmission. METHODS: A prospective study was carried out in 107 patients who were undergoing upper gastrointestinal endoscopy for routine clinical indications. H. pylori DNA was assayed by polymerase chain reaction (PCR) of endoscope washes before and after procedure, in gastric aspirates and in endoscope washes after cleaning and disinfection of endoscopes. Gastric biopsies were assayed by rapid urease test (CLOtest, Tri-Med Specialties Inc., Lenexa, KS) of two antral biopsies. RESULTS: Forty-one of 107 (38%) patients were H. pylori-positive by PCR. Endoscopes were contaminated after 25 of 41 (61%) H. pylori-positive procedures. However, 107 of 107 pre-endoscopy and postcleaning aspirates were negative, indicating that decontamination was 100% effective. The urease test was positive in 25 of 41 H. pylori-positive patients, a sensitivity of 61%. PCR was positive in 41 of 41 H. pylori-positive patients, a sensitivity of 100%. In 5 of 16 PCR-positive/urease-negative patients, the identification of H. pylori was clinically relevant. CONCLUSION: Endoscopes are frequently contaminated with H. pylori after endoscopy in H. pylori-infected patients, but conventional cleaning and disinfection techniques are highly effective in eliminating H. pylori. When appropriate negative control samples are obtained from the endoscope, PCR of endoscopic gastric aspirates appears to be a sensitive test that can detect clinically relevant H. pylori infection that is missed when only a rapid urease test is used.
Assuntos
Desinfecção , Endoscopia do Sistema Digestório/instrumentação , Infecções por Helicobacter/prevenção & controle , Helicobacter pylori , Adulto , Idoso , Idoso de 80 Anos ou mais , Sequência de Bases , Desinfecção/métodos , Endoscopia do Sistema Digestório/efeitos adversos , Feminino , Glutaral , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/transmissão , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Ácido Peracético , Reação em Cadeia da Polimerase , Estudos Prospectivos , Estômago/microbiologiaRESUMO
Release of mucins from cultured airway surface epithelial cells can be stimulated by extracellular ATP via a P2-purinergic receptor-mediated mechanism (K. C. Kim and B. C. Lee. 1991. Br. J. Pharmacol. 103:1053-1056). In this report, we studied the mechanism by which extracellular ATP induces the mucin release. We found that: (1) ATP increased both mucin release and generation of inositol phosphates in a dose-dependent fashion, and their dose-effect relationships were almost superimposed; (2) the increases in both mucin release and the phosphatidylinositol phosphate (PI) turnover by extracellular ATP were partially, but almost equally, blocked by the pretreatment with pertussis toxin (42% for mucin release and 44% for PI turnover). We conclude that in cultured airway goblet cells extracellular ATP stimulates mucin release by a signal transduction mechanism, which seems to involve coupling of ATP-activated P2 purinoceptors with phospholipase C, at least in part, via pertussis toxin-sensitive GTP-binding proteins. This may be an important finding in understanding the regulation of mucin release by airway goblet cells, since a number of agents present in the airway could influence this signal transduction pathway and subsequently modulate the mucin secretion.
Assuntos
Trifosfato de Adenosina/metabolismo , Mucinas/metabolismo , Transdução de Sinais , Traqueia/metabolismo , Animais , Células Cultivadas , Cricetinae , Ativação Enzimática , Proteínas de Ligação ao GTP/metabolismo , Fosfatos de Inositol/biossíntese , Masculino , Mesocricetus , Receptores Purinérgicos/metabolismo , Traqueia/citologia , Traqueia/enzimologia , Fosfolipases Tipo C/metabolismoRESUMO
Human pregnancy-specific beta 1-glycoprotein (SP1) is one of the early pregnancy proteins produced in large quantity by the placenta during pregnancy. The nucleotide sequence of a cDNA encoding human placental SP1 isolated from a term placental cDNA library was determined. This cDNA contains 1,958 nucleotides with a 5' noncoding sequence of 73 bp, a sequence of 1,257 bp encoding a protein of 419 amino acids with calculated molecular mass of 47.2 kD, a TGA stop codon, and 625 bp of 3' noncoding sequence. Two internal repeat domains, each of 93 amino acids, can be identified within the coding sequence. The positions of two cysteine residues within each repeat are conserved. A cDNA of 489 bp identical to the sequence from nucleotides 422-910 of placental SP1 cDNA was isolated from a human testis cDNA library. Screening of a HeLa cell library with SP1 cDNA probe yielded 10 positive clones. Sequence determination of one of the cloned cDNA inserts revealed a partial cDNA of 773 bp which is 94% homologous at the nucleotide level and 88% homologous at the amino acid level to the placental SP1 cDNA. These observations confirm the observation that some of the SP1 genes might be expressed in extraplacental tissues. Searching through the GenBank/EMBL database revealed 74-80% homology between SP1 cDNA with human carcinoembryonic antigen (CEA) cDNA. The multiple genes of SP1 as a subfamily of the immunoglobulin supergene family is implicated.
Assuntos
Antígeno Carcinoembrionário/genética , DNA/análise , Glicoproteínas/genética , Placenta/análise , Proteínas da Gravidez/genética , Sequência de Aminoácidos , Sequência de Bases , Feminino , Humanos , Masculino , Dados de Sequência Molecular , Gravidez , Homologia de Sequência do Ácido NucleicoRESUMO
The isolated mice peritoneal macrophages in degradation of calcium phosphate compound artificial bone--collagen/hydroxylapatite (CHA), hydroxylapatite (HA), beta-tricalcium phosphate (TCP) ceramics, have been studied by use of both Ca++, P concentration assay in cultured supernatant and scanning electron microscopy (SEM). The solubility of Ca++, composition of materials increased more significantly when macrophages were inoculated than when macrophages were not seeded (P < 0.001), and it was shown that the ground materials were wrapped and phagocytized or resorbed extracellularly by macrophages under SEM, suggesting that macrophages could mediate the degradation of calcium phosphate compound artificial bone by phagocytizing and/or degrading extracellularly.
Assuntos
Osso e Ossos , Fosfatos de Cálcio , Macrófagos Peritoneais/imunologia , Fagocitose , Próteses e Implantes , Animais , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Three highly homologous cDNAs encoding human pregnancy-specific beta 1-glycoprotein (SP1) were isolated from a human placental cDNA library. These cDNAs share greater than 90% nucleotide homology in their coding sequences, and greater than 79% of the encoded amino acids are homologous. Proteins encoded by these cDNAs are very similar to members of the carcinoembryonic antigen family and contain repeating domains, conserved disulfide bridges, and beta-sheet structure typical of the immunoglobulin gene superfamily. However, the high degree of sequence homology and relatively lesser degree of glycosylation among the SP1 proteins suggest that they exist as a unique family instead of being members of the CEA family. Both soluble and potentially membrane-bound forms of SP1 proteins were present in the placenta. Northern blot analysis using specific probes confirmed the expression of multiple mRNA species in human term placenta.
Assuntos
DNA/análise , Genes de Imunoglobulinas , Placenta/análise , Proteínas da Gravidez/genética , Glicoproteínas beta 1 Específicas da Gravidez/genética , Sequência de Aminoácidos , Sequência de Bases , Antígeno Carcinoembrionário/genética , Deleção Cromossômica , Clonagem Molecular , Reações Cruzadas , Humanos , Dados de Sequência Molecular , RNA MensageiroRESUMO
Three cDNAs encoding members of the pregnancy-specific beta 1-glycoprotein (PSG) family were isolated from human term placental cDNA library. All three cDNAs encode proteins with similar domain structure. There is a leader sequence of 34 amino acids followed by an N-domain of 109 amino acids. Immediately after the N-domain are one or two copies of a repeating A-domain of 93 amino acids, a B-domain of 85 amino acids and a C-domain of variable size. The proteins are highly hydrophilic. However, one of them has an 81-amino acid C-domain which is very hydrophobic and could potentially serve as a membrane attachment site. The putative cell-cell recognition tripeptide, Arg-Gly-Asp, is present in the N-domain of two of the proteins. Partial sequence of one of the cDNAs has been found in HeLa cells while cDNAs highly homologous to two of the cDNAs have been found in the fetal liver. Functional roles of the PSG proteins basing on their structure are proposed.
Assuntos
Glicoproteínas beta 1 Específicas da Gravidez/química , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Feminino , Biblioteca Gênica , Células HeLa , Humanos , Dados de Sequência Molecular , Família Multigênica/genética , Placenta/química , Gravidez , Conformação Proteica , Alinhamento de SequênciaRESUMO
BACKGROUND: Helicobacter pylori infection has been implicated strongly in the pathogenesis of gastritis, peptic ulcer disease, gastric adenocarcinoma, and gastric lymphoma, but the reasons for these widely different clinical outcomes are unknown. The aim of this study was to determine whether these differences could be due in part to mixed infection in the same individual, with bacteria having differences in pathogenic factors associated with ulcers. MATERIALS AND METHODS: The cagA gene of H. pylori was used to test for mixed infection because it is present in only some strains, and its presence has been associated with ulcers. Polymerase chain reaction (PCR) assays for the cagA gene were applied to H. pylori culture isolates and endoscopic gastric aspirates. Individual bacterial clones were tested for genetic similarity by random primer amplification and restriction endonuclease digestion of urease gene PCR products. RESULTS: The majority of H. pylori-positive patients had strongly cagA-positive culture isolates and endoscopic samples (62.5% and 69.6%, respectively). However, many of these patients had evidence of mixed infection with cagA negative and cagA positive strains in cultures isolates and endoscopic samples (25% and 17.4%, respectively). Mixed infection was found to be due to genetically unrelated strains in two patients in whom genetic analysis was performed. CONCLUSION: Mixed infection with differences in substrain pathogenic factors might occur in H. pylori infection and might contribute to differences in clinical outcome.
Assuntos
Antígenos de Bactérias , Proteínas de Bactérias/genética , Gastrite/microbiologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/patogenicidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteínas de Bactérias/análise , Biomarcadores , Biópsia , DNA Bacteriano/genética , Feminino , Suco Gástrico/microbiologia , Mucosa Gástrica/microbiologia , Gastrite/complicações , Gastroscopia , Genes Bacterianos , Infecções por Helicobacter/complicações , Helicobacter pylori/genética , Helicobacter pylori/isolamento & purificação , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Estudos Prospectivos , Úlcera Gástrica/etiologia , Urease/genética , Virulência/genéticaRESUMO
BACKGROUND: Helicobacter pylori infection persists in the presence of potent serum and gastric mucosal antibody responses against bacterial antigens. The aim of this article is to report on a study determine whether there is antibody deposition on H. pylori in vivo in the stomach of infected patients and whether gastric and cultured forms of H. pylori differ in their antibody reactivity. MATERIALS AND METHODS: Serum, gastric biopsies, and antral brushings were obtained from 10 patients having endoscopy. H. pylori was cultured from gastric biopsies. Bacterial samples were stained directly for immunoglobulin deposition and indirectly using rabbit antiurease serum or patient serum. Samples were examined by immunofluorescence microscopy and flow cytometry. RESULTS: Although spiral bacteria could be identified easily by acridine orange staining and antiurease staining of gastric brushings from H. pylori infected patients, gastric bacteria did not have detectable IgG or IgA present, and only one of five samples could be stained for IgG and IgA indirectly using patient serum. In contrast, cultured bacteria could be stained readily with homologous serum for IgG and IgA in the majority of cases. Low pH inhibited immunoglobulin reactivity with cultured H. pylori. CONCLUSIONS: Gastric H. pylori may evade humoral defense owing to poor deposition of immunoglobulin in the gastric environment or failure to express surface antigens that are present on cultured forms of H. pylori.
Assuntos
Anticorpos Antibacterianos/imunologia , Gastrite/imunologia , Infecções por Helicobacter/imunologia , Helicobacter pylori/imunologia , Receptores de Antígenos de Linfócitos B/imunologia , Animais , Antígenos de Bactérias/imunologia , Técnica Indireta de Fluorescência para Anticorpo , Ácido Gástrico , Gastrite/microbiologia , Humanos , Imunoglobulina A/imunologia , Imunoglobulina G/imunologia , CoelhosRESUMO
Extracellular ATP can stimulate mucin release from primary hamster tracheal surface epithelial (HTSE) cells via a P2 purinoceptor-mediated mechanism, based on agonist potency studies of mucin release (Br. J. Pharmacol. 1991; 103:1053-1056). In the present study, we examined the kinetics of ATP binding to the surface of intact HTSE cells at 4 degrees C using ATP gamma S35 as a radioligand. We found that ATP gamma S35 bound to HTSE cells in a saturable, reversible manner, reaching an equilibrium at about 30 min. Scatchard analysis of equilibrium binding suggested the presence of two binding sites with Kd values of 0.47 and 9.4 microM. Competitive binding experiments, based on the ability of nucleotides and ATP analogs to block ATP gamma S35 revealed a rank order of ATP > ADP > alpha,beta-methylene ATP > 2-methylthio ATP > or = beta, gamma-methylene ATP. Neither AMP nor adenosine could inhibit the ATP gamma S35 binding. A comparison between the ability of nucleotides to compete with ATP gamma S35 binding and their ability to induce mucin release revealed a rather poor correlation (r2 = 0.67) with all of the above nucleotides but a good correlation (r2 = 0.96) without 2-methylthio ATP, indicating the presence of heterogenous ATP binding sites on the HTSE cell surface. UTP, a pyrimidine nucleotide, which is almost equipotent with ATP in its ability to stimulate mucin release, was much less potent than ATP in its ability to displace the ATP gamma S35 binding in these HTSE cells.
Assuntos
Trifosfato de Adenosina/análogos & derivados , Traqueia/metabolismo , Nucleotídeos de Adenina/farmacologia , Adenosina/farmacologia , Trifosfato de Adenosina/metabolismo , Animais , Sítios de Ligação , Células Cultivadas , Cricetinae , Células Epiteliais , Epitélio/efeitos dos fármacos , Epitélio/metabolismo , Cinética , Masculino , Mesocricetus , Receptores Purinérgicos/metabolismo , Radioisótopos de Enxofre , Traqueia/citologia , Traqueia/efeitos dos fármacos , Uridina Trifosfato/farmacologiaRESUMO
The authors have prepared the artificial bone of porous tricalcium phosphate ceramics according to an appropriate formula and manufacturing technology. Physical and chemical testing shows that it possesses several distinguishing features: the communicating pores and macro/micropores; mean pore size, 380 microns (from 240 microns to 510 microns); porosity, 46.4%; and compressive strength, 97.4 kg/cm2. It consists of CaO (49.09%) and P2O5 (48.84%). The testing of its biocompatibility shows that it is devoid of systemic or local toxicity, and free of irritation or foreign body response in tissues, and it does not result in hemolysis or mutation. The new bone readily grows into its pores with direct contact to the implanted material. 11 cases of bone defects were treated with this artificial bone with satisfactory results.
Assuntos
Materiais Biocompatíveis , Neoplasias Ósseas/cirurgia , Fosfatos de Cálcio , Osteocondroma/cirurgia , Adolescente , Adulto , Animais , Cistos Ósseos/cirurgia , Osso e Ossos/cirurgia , Cerâmica , Criança , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Próteses e Implantes , Coelhos , Ratos , Ratos Wistar , Difração de Raios XRESUMO
We utilized the [(35)S]-GTP-gamma-S functional binding assay to determine the selectivity of opioid receptor agonists in guinea pig caudate membranes. The study focused on two opioid agonists used for treating opioid-dependent patients: methadone and buprenorphine. Selective antagonists were used to generate agonist-selective conditions: TIPP + nor-BNI to measure mu receptors, CTAP + nor-BNI to measure gamma receptors and TIPP + CTAP to measure kappa receptors. The assay was first validated with opioid agonists of known subtype specificity (DAMGO for mu, SNC80 for delta, and U69, 593 for kappa receptors). Methadone-stimulated [(35)S]-GTP-gamma-S binding was mu-specific and less potent and efficacious than etorphine (K(d) = 1,537 nM vs. K(d) = 7.8 nM). Buprenorphine failed to stimulate [(35)S]-GTP-gamma-S binding but inhibited agonist-stimulated [(35)S]-GTP-gamma-S binding. The antagonist-K(i) values (nM) of buprenorphine at mu, delta, and kappa receptors were 0.088 nM, 1.15 nM, and 0.072 nM, respectively. The antagonist-K(i) values (nM) of naloxone at mu, delta, and kappa receptors were 1.39 nM, 25.0 nM, and 11.4 nM, respectively. Autoradiographic studies showed that buprenorphine failed to stimulate [(35)S]-GTP-gamma-S binding in caudate-level rat brain sections but blocked DAMGO-stimulated [(35)S]-GTP-gamma-S binding. In cells expressing the cloned rat mu receptor, buprenorphine was a partial agonist and potent mu antagonist. Administration of buprenorphine to rats produced a long-lasting (>24 h) decrease in mu and kappa2 receptor binding and attenuated mu-stimulated [(35)S]-GTP-gamma-S binding. Viewed collectively, these data indicate that, in this assay system, buprenorphine is a potent mu and gamma receptor antagonist. The clinical implications remain to be elucidated. Synapse 34:83-94, 1999. Published 1999 Wiley-Liss, Inc.
Assuntos
Benzenoacetamidas , Buprenorfina/farmacologia , Antagonistas de Entorpecentes/farmacologia , Putamen/efeitos dos fármacos , Animais , Benzamidas/farmacologia , Avaliação Pré-Clínica de Medicamentos , Ala(2)-MePhe(4)-Gly(5)-Encefalina/farmacologia , Cobaias , Masculino , Camundongos , Piperazinas/farmacologia , Pirrolidinas/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores Opioides kappa/agonistasRESUMO
Previous data obtained with the cloned rat mu opioid receptor demonstrated that the "super-potent" opiates, ohmefentanyl (RTI-4614-4) and its four enantiomers, differ in binding affinity, potency, efficacy, and intrinsic efficacy. Molecular modeling (Tang et al., 1996) of fentanyl derivatives binding to the mu receptor suggests that Asp147, Tyr148, Trp318, and His319 are important residues for binding. According to this model, Asp147 interacts with the positively charged opiate agonist to form potent electrostatic and hydrogen-bonding interactions. In this study, the role of weak electrostatic and hydrogen-bonding "pi-pi" interactions of the O atom of the carbonyl group and the phenyl ring structures of RTI-4614-4 and its four enantiomers with residues Tyr148, Trp318, and His319 were explored via site-directed mutagenesis. Tyr148 (in transmembrane helix 3 {TMH3}), Trp318 (TMH7), and His319 (TMH7) were individually replaced with phenylalanine or alanine. Receptors transiently expressed in COS-7 cells were labeled with [125I]IOXY according to published procedures. Mutation of Tyr148 to phenylalanine reduced the binding affinities of some mu-selective agonists (2-7 fold) but did not alter the affinities of DAMGO, naloxone, and the non-selective opiates etorphine and buprenorphine. In contrast, this mutation significantly increased the binding affinities (decreased the Kd values) of [D-Ala2,D-Leu5]enkephalin, IOXY, and dermorphin. Mutation of Trp318 decreased opioid receptor binding to almost undetectable levels. Substitution of alanine for His319 significantly reduced binding affinities for the opioid ligands tested (1.3- to 48-fold), but did not alter the affinities of naloxone and bremazocine. These results indicate the importance of Tyrl48 and His319 for the binding of fentanyl derivatives to the mu receptor. Functional studies using the mutant receptors will provide additional insight into the mechanism of action of RTI-4614-4 and its four enantiomers.