RESUMO
This cross sectional study was carried out in the department of gastroenterology, BIRDEM, Dhaka from January 2010 to May 2011 to determine the role of ascitic fluid ADA and serum CA-125 in the diagnosis of clinically suspected tubercular peritonitis. Total 30 patients (age 39.69 ± 21.26, 18M/12F) with clinical suspicion of tuberculosis peritonitis were included in this study after analyzing selection criteria. Laparoscopic peritoneal biopsy with 'histopathological diagnosis' was considered gold standard against which accuracics of two biomarkers (ADA & CA-125) were compared. Cut off value of ADA and CA-125 are 24 u/l, 35 U/ml respectively. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of ADA as a diagnostic modality in tuberculos peritonitis were 87.5%, 83.33%, 95.45%, 62.5% and 86.67% respectively where as CA-125 was found to have 83.33% sensitivity, 50% specificity, 86.9% positive predictive value, 42.85% negative predictive value and 76.6% accuracy. Both biomarkers are simple, non-invasive, rapid and relatively cheap diagnostic test where as laparoscopy is an invasive procedure, costly & requires trained staff and not without risk and also not feasible in all the centre in our country. So ascitic fluid ADA and serum CA-125 are important diagnostic test for peritoneal tuberculosis.
Assuntos
Adenosina Desaminase/análise , Líquido Ascítico/química , Antígeno Ca-125/sangue , Peritonite Tuberculosa/diagnóstico , Adolescente , Adulto , Estudos Transversais , Diagnóstico Diferencial , Humanos , Entrevistas como Assunto , Pessoa de Meia-Idade , Pesquisa Qualitativa , Sensibilidade e Especificidade , Adulto JovemRESUMO
Double balloon enteroscopy (DBE) is a newly developed endoscopic modality for diagnosis and treatment of small bowel disorders. The aim of this study was to evaluate the diagnostic and therapeutic impact of DBE in patient with suspected small bowel disease. This was a prospective study. Sixty one double balloon enteroscopy procedures (30 antegrade 31 retrograde) were done in thirty six patients (20M/16F, mean age 40 ± 12.5 range 16-65 years ) at gastroenterology department, Sir Salimullah Medical College, Dhaka between October 2011 and September 2012. Indications for DBE included chronic abdominal pain 14 (38.9%), obscure GI bleeding 11 (30.56%), Small bowel obstruction 05 (13.89%), and chronic diarrhea 06 (16.67%). The morphologic findings were ulcerations 13 (36.11%), growth 03 (8.33%), vascular ectasia 03 (8.33%) and polyp 01 (2.78%). Therapeutic interventions were performed in one patient only. No serious complications were observed. Diagnostic yields in case of chronic abdominal pain, chronic diarrhea, obscure GI bleeding and small bowel obstruction were 50%, 66%, 63% and 40% respectively. The findings were adenocarcinoma 04 (11%), lymphoma 03 (8.4%), tuberculosis 03 (8.4%), non specific findings 05 (13.9%), IPSID 01(2.8%), Crohn's disease 01 (2.8%), vascular ectasia 03 (8.33%) and normal 16 (44.44%). DBE is well tolerated, feasible and useful technique for the diagnosis as well as treatment of small intestinal disorders.
Assuntos
Enteroscopia de Duplo Balão , Enteropatias/diagnóstico , Enteropatias/cirurgia , Intestino Delgado , Adolescente , Adulto , Idoso , Bangladesh , Estudos de Coortes , Feminino , Humanos , Enteropatias/etiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto JovemRESUMO
To bridge the gap between two-dimensional cell culture and tissue, various three-dimensional (3-D) cell culture approaches have been developed for the investigation of cardiac myocytes (CMs) and cardiac fibroblasts (CFs). However, several limitations still exist. This study was designed to develop a cardiac 3-D culture model with a scaffold-free technology that can easily and inexpensively generate large numbers of microtissues with cellular distribution and functional behavior similar to cardiac tissue. Using micromolded nonadhesive agarose hydrogels containing 822 concave recesses (800 µm deep × 400 µm wide), we demonstrated that neonatal rat ventricular CMs and CFs alone or in combination self-assembled into viable (Live/Dead stain) spherical-shaped microtissues. Importantly, when seeded simultaneously or sequentially, CMs and CFs self-sorted to be interspersed, reminiscent of their myocardial distribution, as shown by cell type-specific CellTracker or antibody labeling. Microelectrode recordings and optical mapping revealed characteristic triangular action potentials (APs) with a resting membrane potential of -66 ± 7 mV (n = 4) in spontaneously contracting CM microtissues. Under pacing, optically mapped AP duration at 90% repolarization and conduction velocity were 100 ± 30 ms and 18.0 ± 1.9 cm/s, respectively (n = 5 each). The presence of CFs led to a twofold AP prolongation in heterogenous microtissues (CM-to-CF ratio of 1:1). Importantly, Ba(2+)-sensitive inward rectifier K(+) currents and Ca(2+)-handling proteins, including sarco(endo)plasmic reticulum Ca(2+)-ATPase 2a, were detected in CM-containing microtissues. Furthermore, cell type-specific adenoviral gene transfer was achieved, with no impact on microtissue formation or cell viability. In conclusion, we developed a novel scaffold-free cardiac 3-D culture model with several advancements for the investigation of CM and CF function and cross-regulation.
Assuntos
Comunicação Celular/fisiologia , Fibroblastos/citologia , Modelos Animais , Miócitos Cardíacos/citologia , Engenharia Tecidual/métodos , Potenciais de Ação/fisiologia , Animais , Células Cultivadas , Estimulação Elétrica , Fibroblastos/fisiologia , Hidrogéis , Potenciais da Membrana/fisiologia , Microeletrodos , Miócitos Cardíacos/fisiologia , Ratos , Ratos Sprague-DawleyRESUMO
Helicobacter Pylori (H Pylori) that infects about 90% people of developing countries causes dyspepsia and upper gastrointestinal lesions. The aim of this study was to detect the trend of H Pylori active infection and to investigate the endoscopic findings of H Pylori infected dyspeptic patient of Bangladesh. In this prospective study, 360 dyspeptic patients (Male-251, Female-109) were recruited. Patients having alarm features, history of gastrectomy and malignancy were excluded from this study. Non-invasive fecal antigen test for H Pylori was done of all patients. All selected patients were sent for upper gastrointestinal endoscopy. Helicobacter Pylori fecal antigen was found positive in 134(37.2%) from 360 dyspeptic patients (age 14-80 years). Among 360 patients 303 (80.16%) had macroscopic endoscopic mucosal lesions. H Pylori infected 114 patients had endoscopic mucosal abnormality. H Pylori non-infected 189 patients also had mucosal lesion. Twenty patients (35.08%) had H Pylori infection among the 57 patients having endoscopic normal looking mucosa. This study revealed that active H Pylori infection rate is declining in Bangladesh. Risk of endoscopic mucosal lesion is more expected in H Pylori active infection.
Assuntos
Dispepsia , Infecções por Helicobacter , Helicobacter pylori , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Dispepsia/epidemiologia , Fezes , Feminino , Infecções por Helicobacter/complicações , Infecções por Helicobacter/diagnóstico , Infecções por Helicobacter/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto JovemRESUMO
Chronic hepatitis B and C virus infection can lead to cirrhosis and hepatocellular carcinoma. Several studies investigated the diagnostic and prognostic value of some biochemical markers to detect the hepatic fibrosis and found a correlation between serum markers and hepatic fibrosis. Among them serum hyaluronic acid (HA) has been identified as a potential marker of fibrosis or cirrhosis in different studies. A prospective study in 60 subjects was conducted to evaluate the association between serum HA and hepatic fibrosis. Thirty consecutive patients with chronic HBV or HCV infection undergoing liver biopsy were studied. Sera were obtained for HA using enzyme linked protein binding assay. Patients with hepatic fibrosis had higher serum HA concentration compared with healthy subjects (236.65 ± 227.07 vs. 23.32 ± 14.22 respectively, p<0.001). Correlation was found between high serum HA concentration and increasing degree of hepatic fibrosis (R-0.322 and p<0.041). This study had shown a good correlation between serum HA and different stages of hepatic fibrosis. So serum HA may be used as a useful marker of hepatic fibrosis.
Assuntos
Hepatite B Crônica/complicações , Hepatite C Crônica/complicações , Ácido Hialurônico/sangue , Cirrose Hepática/diagnóstico , Adulto , Feminino , Hepatite B Crônica/sangue , Hepatite C Crônica/sangue , Humanos , Cirrose Hepática/sangue , Cirrose Hepática/etiologia , Masculino , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
Carabeef samples were sliced, pressed, cured and divided into 6 groups. Starter cultures (Micrococcus varians M483 (MV), Staphylococcus carnosus (SC), Lactobacillus sakei (LS), M. varians M483+ Lb. sakei and Staph. carnosus + Lb. sakei) were inoculated at the dose of 10(6)-0(7)cfu/g and stored at 10 ± 1°C for 7 days. Uninoculated samples were maintained as control. Samples were then divided into 2 treatment groups. Samples of treatment 1 (T1) were smeared with a paste of turmeric followed by application of a thick layer of the paste of garlic, cumin, black pepper and red pepper whereas, samples of treatment 2 (T2) were applied with a thick layer of spices as above without turmeric. With the gradual fall in pH there was a reduction in water-holding capacity (WHC) of samples. The WHC of samples treated with SC+LS of T1 reduced to 6.3 ± 0.03 cm(2) and those inoculated with MV+LS of T2 to 6.2 ± 0.03 cm(2). The extract release volume (ERV) increased in all samples during storage. The least ERV of 11.7 and 11.6 ml were recorded in samples inoculated with MV of T1 and T2, respectively. The tyrosine (TV) and thiobarbituric acid (TBA) number of turmeric treated samples were significantly lower than non turmeric treated samples. The samples inoculated with LS had the least TV of 30.9 mg tyrosine/100 g of meat and TBA number of 0.06 mg manoladehyde/kg of meat. Samples inoculated with MV and LS of both T1 and T2 were better in physico-chemical qualities.
RESUMO
Globus sensation is a subjective feeling of a lump or foreign body in the throat without interfering swallowing of food. It is a persistent and distressing sensation in throat. It affects about 6% of population. But cause of globus is still unknown. Exact aetiology of globus is considered to be multifactorial. Some other studies also show association between globus and psychological distress including anxiety and depression. As there is no established pharmacological treatment, adequate investigations with negative result could reassure patients and improve their symptoms. In this prospective study consecutive patients with globus symptoms examined by upper GIT endoscopy with attention to larynx, epiglottis, base of tongue, both pyriform fossa and hypo-pharynx using Olympus forward viewing video Gastroscope (GIF Q-150 & GIF Q-170) to exclude organic lesion and was conducted in the department of Gastroenterology, Bangabandhu Sheikh Mujib Medical University (BSMMU) and North East Medical College, Sylhet from 1st July 2014 to 31 December 2016. Their psychological status and epidemiological information including personal and family history were noted in a pre-designed data sheet. Total 104 patients were examined, among them definite anxiety was found in 36(34.95%) and borderline feature of anxiety was found in 19(18.44%) and 48(46.60%) were free of anxiety. Incidence of anxiety was significantly higher among females and was more prevalent among housewife, married people and people from rural community. In this series, 13(12.5%) patients had definite depression and 29(27.9%) patients had borderline depression, while 61(59.2%) patients had no feature of depression. Incidence of depression was significantly higher among females, housewife and married people. Organic lesion is rare in patients with globus symptoms. Globus sensation is more common among females. Psychological factors like anxiety and depression are frequently associated with globus sensation.
Assuntos
Transtornos da Motilidade Esofágica/diagnóstico , Esofagoscopia , Faringe/inervação , Transtornos de Sensação/etiologia , Sensação/fisiologia , Ansiedade/epidemiologia , Bangladesh/epidemiologia , Endoscopia , Transtornos da Motilidade Esofágica/epidemiologia , Feminino , Humanos , Prevalência , Estudos Prospectivos , Transtornos de Sensação/diagnóstico , Transtornos de Sensação/epidemiologiaRESUMO
E2F transcription factor is subject to stringent regulation by a variety of molecules. We recently observed that prohibitin, a potential tumor suppressor protein, binds to the retinoblastoma (Rb) protein and represses E2F transcriptional activity. Here we demonstrate that prohibitin requires the marked box region of E2F for repression; further, prohibitin can effectively inhibit colony formation induced by overexpression of E2F1 in T47D cells. Prohibitin was also found to interact with the signaling kinase c-Raf-1, and Raf-1 could effectively reverse prohibitin-mediated repression of E2F activity. Agents such as E1A, p38 kinase, and cyclins D and E had no effect on prohibitin-mediated repression of E2F1, but all of these molecules could reverse Rb function. Similarly, stimulation of the immunoglobulin M signaling pathway in Ramos cells could inactivate prohibitin, but this had no effect on Rb function. Serum stimulation of quiescent Ramos cells inactivated Rb and prohibitin with different kinetics; further, while the serum-dependent inactivation of Rb was dependent on cyclin-dependent kinase activity, the inactivation of prohibitin was not. We believe that prohibitin is a novel regulator of E2F function which channels specific signaling cascades to the cell cycle regulatory machinery.
Assuntos
Proteínas de Transporte , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Proteínas/metabolismo , Proteínas Repressoras , Proteína do Retinoblastoma/metabolismo , Fatores de Transcrição/metabolismo , Sítios de Ligação , Ensaio de Unidades Formadoras de Colônias , Quinases Ciclina-Dependentes/metabolismo , Fatores de Transcrição E2F , Fator de Transcrição E2F1 , Regulação da Expressão Gênica , Proibitinas , Ligação Proteica , Proteínas Proto-Oncogênicas c-raf/metabolismo , Receptor Cross-Talk , Receptores Fc/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Proteína 1 de Ligação ao Retinoblastoma , Transdução de Sinais , Transcrição GênicaRESUMO
The retinoblastoma tumor suppressor protein and its family members, p107 and p130, are major regulators of the mammalian cell cycle. They exert their growth suppressive effects at least in part by binding the E2F family of transcription factors and inhibiting their transcriptional activity. Agents that disrupt the interaction between Rb family proteins and E2F promote cell proliferation. Here we describe the characterization of a novel interaction between Rb family proteins and a potential tumor suppressor protein, prohibitin. Prohibitin physically interacts with all three Rb family proteins in vitro and in vivo, and was very effective in repressing E2F-mediated transcription. Prohibitin could inhibit the activity of E2Fs 1, 2, 3, 4 and 5, but could not affect the activity of promoters lacking an E2F site. Surprisingly, prohibitin-mediated repression of E2F could not be reversed by adenovirus E1A protein. A prohibitin mutant that could not bind to Rb was impaired in its ability to repress E2F activity and inhibit cell proliferation. We believe that prohibitin is a novel regulator of E2F activity that responds to specific signaling cascades.
Assuntos
Proteínas de Transporte , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Proteínas/fisiologia , Proteínas Repressoras , Proteína do Retinoblastoma/fisiologia , Fatores de Transcrição/fisiologia , Ativação Transcricional/fisiologia , Animais , Divisão Celular/fisiologia , Fatores de Transcrição E2F , Humanos , Camundongos , Proteínas Nucleares/fisiologia , Fosfoproteínas/fisiologia , Proibitinas , Proteínas/genética , Proteína 1 de Ligação ao Retinoblastoma , Proteína p107 Retinoblastoma-Like , Proteína p130 Retinoblastoma-Like , Fator de Transcrição DP1 , Transfecção , Células Tumorais CultivadasRESUMO
p21(waf1/cip1), an important regulator of the cell cycle, binds to PCNA and acts as a mediator of the growth suppressing and apoptosis promoting functions of p53. We report a hitherto unobserved polymorphism in the carboxy terminal domain (codon 149) of p21(waf1/cip1) gene, the domain encoding the PCNA binding motif. The codon 149 polymorphism (GAT-->GGT) was observed in 42 of 50 (84%) esophageal squamous cell carcinomas (ESCCs) and eight of 50 (16%) normal individuals. The resultant amino acid substitution from aspartate to glycine may have vital implication in PCNA mediated cell cycle regulation by p21(waf1/cip1). The second polymorphism at codon 31, involving a C-->A transversion at nucleotide 168 (AGC-->AGA) changing the amino acid from serine to arginine, was observed in 2/50 (4%) ESCCs at a relatively lower frequency in the Indian population than that reported in the West. No significant association was observed between p21(wap1/cip1) polymorphism at codon 149 and p21(wap1/cip1) protein expression in ESCC in this cohort of patients. Interestingly, the frequency of p21(wap1/cip1) variants (codon 149) in ESCCs (18 of 19 cases) with wild-type p53 was significantly higher than in tumors with p53 mutations, suggesting that this polymorphism affects the p53 pathway and may play an important role in esophageal tumorigenesis. Analysis of p21(waf1/cip1) expression in relation to p53 gene and protein status revealed its induction by p53-dependent as well as independent pathways in esophageal tumorigenesis.
Assuntos
Carcinoma de Células Escamosas/genética , Ciclinas/genética , Neoplasias Esofágicas/genética , Polimorfismo Genético , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/análise , Genes p53 , Humanos , Imuno-Histoquímica , Antígeno Nuclear de Célula em Proliferação/metabolismoRESUMO
Calcium ions produce a 3-4-fold stimulation of the actin-activated ATPase activities of phosphorylated myosin from bovine pulmonary artery or chicken gizzard at 37 degrees C and at physiological ionic strengths, 0.12-0.16 M. Actins from either chicken gizzard or rabbit skeletal muscle stimulate the activity of phosphorylated myosin in a Ca2+-dependent manner, indicating that the Ca2+ sensitivity involves myosin or a protein associated with it. Partial loss of Ca2+ sensitivity upon treatment of phosphorylated gizzard myosin with low concentrations of chymotrypsin and the lack of any change on similar treatment of actin supports the above conclusion. Although both actins enhance ATPase activity, activation by gizzard actin exhibits Ca2+ dependence at higher temperatures or lower ionic strengths than does activation by skeletal muscle actin. The Ca2+ dependence of the activity of phosphorylated heavy meromyosin is about half that of myosin and is affected differently by temperature, ionic strength and Mg2+, being independent of temperature and optimal at lower concentrations of NaCl. Raising the concentration of Mg2+ above 2-3 mM inhibits the activity of heavy meromyosin but stimulates that of myosin, indicating that Mg2+ and Ca2+ activate myosin at different binding sites.
Assuntos
Actinas/metabolismo , ATPases Transportadoras de Cálcio/metabolismo , Músculo Liso Vascular/enzimologia , Músculo Liso/enzimologia , Miosinas/metabolismo , Tropomiosina/metabolismo , Animais , Bovinos , Galinhas , Moela das Aves/enzimologia , Cinética , Concentração Osmolar , Fosforilação , Artéria Pulmonar/enzimologia , Cloreto de Sódio/farmacologia , TermodinâmicaRESUMO
The level of superoxide anion was found to be significantly elevated in polymorphonuclear leukocytes (PMNL) from diabetic subjects as compared with those from normal subjects. This elevation was attributed to the significant reduction in the activities of both cytoplasmic and mitochondrial superoxide dismutase (SOD), the effect being more pronounced in the cytoplasmic fraction. Although the content of copper decreased considerably in the diabetic PMNL, the decrease in the zinc content was less significant, with an insignificant alteration in the content of manganese. PMNL obtained from insulin-treated diabetic patients showed considerable alleviation of SOD levels. The implication of these results are discussed herein.
Assuntos
Diabetes Mellitus/enzimologia , Neutrófilos/enzimologia , Superóxido Dismutase/sangue , Adulto , Cobre/sangue , Humanos , Masculino , Manganês/sangue , Pessoa de Meia-Idade , Superóxidos/sangue , Zinco/sangueRESUMO
Epidemiological studies have demonstrated an association between human esophageal cancer and dietary/nutritional risk factors in developing countries. We examined the expression of p53 protein in 51 cases of esophageal squamous cell carcinomas (ESCCs) and paired normal esophageal tissues by immunohistochemistry. Alterations in the tumor suppressor gene p53 (exons 5-8) were analyzed in 51 cases of ESCC and paired normal tissues by PCR and single-strand conformation polymorphism. p53 protein expression was correlated with major dietary risk factors and common carcinogens identified in India. Immunohistochemical analysis of frozen esophageal tissue sections using anti-p53 monoclonal antibody (D0-1) showed overexpression of the protein in the nuclei of epithelial cells in 39 of 51 (76%) cases. The histopathologically proven normal esophageal tissue sections taken from a distant site from esophageal cancer patients did not show any detectable level of p53 immunoreactivity. The PCR-single-strand conformation polymorphism analysis showed a mobility shift in 37 of 51 (72%) ESCCs. Intake of chilies was positively associated with p53 protein expression (P < 0. 01) in the esophageal cancerous lesions. Our results suggest that p53 alterations are frequent events in esophageal oncogenesis in the Indian population, which has dietary habits that are considerably different from those of the Western population.
Assuntos
Carcinoma de Células Escamosas/epidemiologia , Carcinoma de Células Escamosas/genética , Dieta , Neoplasias Esofágicas/epidemiologia , Neoplasias Esofágicas/genética , Genes p53 , Mutação , Proteína Supressora de Tumor p53/genética , Adulto , Idoso , Carcinógenos , Carcinoma de Células Escamosas/química , Carcinoma de Células Escamosas/patologia , Neoplasias Esofágicas/química , Neoplasias Esofágicas/patologia , Esôfago/metabolismo , Esôfago/patologia , Éxons , Comportamento Alimentar , Feminino , Humanos , Immunoblotting , Imuno-Histoquímica , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Fatores de Risco , Proteína Supressora de Tumor p53/análiseRESUMO
p53 aberrations are early events in the pathogenesis of betel- and tobacco-related oral malignancies. Accumulation of p53 protein in oral lesions may elicit a humoral immune response against p53 protein in these patients. p53 antibodies (Abs) were analyzed in 183 sera obtained from patients with premalignant or malignant oral lesions and normal individuals by enzyme-linked immunoassay using recombinant p53 protein as antigen. These results were correlated with accumulation of p53 protein in patients' matched oral tissue specimens. Circulating p53 Abs were observed in 24 of 70 (34%) cancer patients and 15 of 50 (30%) patients with premalignant oral lesions. p53 Abs showed a significant association with increase in tumor size and dedifferentiation of tumors, factors indicative of poor prognosis. Expression of p53 protein was analyzed in 43 matched oral lesions (18 premalignant and 25 malignant cases). All the p53-seropositive patients (7 leukoplakia and 11 squamous cell carcinoma) showed elevated levels of p53 protein in matched oral lesions. However, the total number of patients seropositive for p53 Abs was lesser than that of patients exhibiting p53 protein accumulation in oral lesions. Four of the 63 normal healthy individuals who were heavy consumers of tobacco (smoking/chewing) and betel were found to be positive for p53 Abs. Detection of circulating p53 Abs in patients with premalignant oral lesions suggests that humoral immune response against p53 protein is an early event in oral oncogenesis and may be a surrogate marker for both p53 alteration and preclinical cancer.
Assuntos
Anticorpos Antineoplásicos/sangue , Biomarcadores Tumorais/sangue , Carcinoma de Células Escamosas/sangue , Neoplasias Bucais/sangue , Proteína Supressora de Tumor p53/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Autoanticorpos/sangue , Carcinoma de Células Escamosas/imunologia , Feminino , Humanos , Técnicas Imunoenzimáticas , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/imunologia , Plantas Tóxicas , Lesões Pré-Cancerosas/sangue , Lesões Pré-Cancerosas/imunologia , Prognóstico , Fumar/efeitos adversos , Tabaco sem Fumaça/efeitos adversos , Proteína Supressora de Tumor p53/biossíntese , Proteína Supressora de Tumor p53/sangueRESUMO
The limited throughput, scalability and high cost of protein purification by chromatography provide motivation for the development of non-chromatographic protein purification technologies that are cheaper and easier to implement in a high-throughput format for proteomics applications and to scale up for industrial bioprocessing. We have shown that genetic fusion of a recombinant protein to an elastin-like polypeptide (ELP) imparts the environmentally sensitive solubility property of the ELP to the fusion protein, and thereby allows selective separation of the fusion protein from Escherichia coli lysate by aggregation above a critical temperature (T(t)). Further development of ELP fusion proteins as widely applicable purification tools necessitates a quantitative understanding of how fused proteins perturb the ELP T(t) such that purification conditions (T(t)) may be predicted a priori for new recombinant proteins. We report here the effect that fusing six different proteins has on the T(t) of an ELP. A negative correlation between T(t) and the fraction hydrophobic surface area on the fused proteins was observed, which was determined from computer modeling of the available three-dimensional structure. The thermally triggered aggregation behavior of ELP-coated, functionalized gold colloids as well as ligand binding to the tendamistat-ELP fusion protein support the hypothesis that hydrophobic surfaces in molecular proximity to ELPs depress the ELP T(t) by a mechanism analogous to hydrophobic residue substitution in the ELP repeat, Val-Pro-Gly-Xaa-Gly.
Assuntos
Peptídeos/química , Engenharia de Proteínas/métodos , Proteínas Recombinantes de Fusão/química , Sequência de Aminoácidos , Bases de Dados como Assunto , Escherichia coli/metabolismo , Coloide de Ouro/química , Ligantes , Modelos Moleculares , Dados de Sequência Molecular , Plasmídeos/metabolismo , Conformação Proteica , Dobramento de Proteína , Homologia de Sequência de Aminoácidos , Solubilidade , Ressonância de Plasmônio de Superfície , Temperatura , TermodinâmicaRESUMO
A highly sensitive technique for determining the subtype specificity of antibody to hepatitis B surface antigen (anti-HBs) is described. Immunoadsorbent consisting of controlled pore glass coated with subtype specific HBsAg was used to remove homologous antibody from the test samples before testing them for residual antibody by a commercially available radioimmunoassay (RIA). A total of 73 anti-HBs-positive samples from asymptomatic blood donors were tested. In nearly 80% of these samples the subtype reactivity could be determined by this technique. Only 67% could be typed by conventional liquid phase absorption RIA and 22% by passive hemagglutination inhibition techniques. Among the samples with low anti-HBs titer, ad and ay subtypes were found with equal frequency; however, with the increase in anti-HBs titer, considerably higher proportion of ad specificity was detected.
Assuntos
Anticorpos Antivirais/análise , Anticorpos Anti-Hepatite B/análise , Antígenos de Superfície da Hepatite B/imunologia , Testes de Inibição da Hemaglutinação , Humanos , Radioimunoensaio/métodosRESUMO
A comparative evaluation of six licensed radioimmunoassay kits for the detection of hepatitis B surface antigen (HBsAg) has been performed. Each method met the federal licensure requirements for the test. The performance of the kits varied considerably, however, when they were challenged to the limits of their sensitivities. During the period December 1978 through March 1979, four kits were judged to be of equivalent high sensitivity, whereas two were less sensitive. Three of the kits, including two of those with high sensitivity, generated a high (6%--7%) proportion of false reactive results. The sensitivities of all kits decreased during the shelf lives of the reagents.
Assuntos
Antígenos de Superfície da Hepatite B/análise , Radioimunoensaio/métodos , Kit de Reagentes para Diagnóstico/normas , Estudos de Avaliação como AssuntoRESUMO
The enzyme, 11 beta-hydroxysteroid dehydrogenase converts the active glucocorticoids cortisol and corticosterone to their inactive 11-oxo metabolites cortisone and dehydrocorticosterone, respectively. The properties of the human placental 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) were studied. The enzyme was active in the oxidative and reductive directions. pH optimum for 11 beta-dehydrogenase activity was in the range of 7-10 and for 11-oxoreductase it was in the range of 5.5-6.0. The crude placental homogenate was unstable. Reductase activity was more labile than dehydrogenase activity. Removal of cytosol enabled the enzyme to retain activity. 11 beta-HSD a membrane bound enzyme was distributed in all particulate subcellular fractions. Addition of detergent released latent activity of 11 beta-dehydrogenase and inactivated 11-reductase activity. Both corticosterone and cortisol were substrates for the enzyme. The Km value with corticosterone as substrate was much lower than with cortisol. The Km values with cortisone and dehydrocorticosterone were similar.
Assuntos
Hidroxiesteroide Desidrogenases/metabolismo , Placenta/enzimologia , 11-beta-Hidroxiesteroide Desidrogenases , Membrana Celular/enzimologia , Núcleo Celular/enzimologia , Corticosterona/metabolismo , Estabilidade Enzimática , Feminino , Humanos , Hidrocortisona/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Microssomos/enzimologia , Mitocôndrias/enzimologia , NAD/farmacologia , Oxirredução , Placenta/ultraestrutura , Gravidez , Especificidade por SubstratoRESUMO
Guinea pig prostate was found to actively participate in the biosynthesis and catabolism of ascorbic acid. The key ascorbic acid biosynthetic enzyme L-gulono-gamma-lactone oxidase and the other two lactonases were found to be present in guinea pig prostate. The activities of dehydroascorbatase and diketogulonate decarboxylase, the enzymes for ascorbic acid degradation, were also detected in guinea pig prostate. Male guinea pigs kept under scorbutic condition for 7, 14, 21 and 28 days, were examined for prostatic metabolism of ascorbic acid. A significant but gradual decrease in the concentration of L-ascorbic acid was observed in prostate, total blood and leukocytes with the progression of scorbutic condition. There was an appreciable decrease in the rate of lipid peroxidation under the scorbutic condition. In the tissue fraction of scorbutic guinea pigs, the activities of biosynthesizing enzymes, measured in vitro, under optimum conditions were found to be higher with no significant alterations in the catabolizing enzymes. The implications of these findings are discussed in this paper.
Assuntos
Ácido Ascórbico/metabolismo , Próstata/metabolismo , Escorbuto/metabolismo , Animais , Ácido Ascórbico/sangue , Cobaias , Leucócitos/metabolismo , Peróxidos Lipídicos/biossíntese , Masculino , Tamanho do Órgão , Próstata/enzimologia , Escorbuto/sangueRESUMO
Corynebacteria are pleomorphic, asporogenous, Gram-positive bacteria. Included in this group are nonpathogenic soil corynebacteria, which are widely used for the industrial production of amino acids and detergents, and in biotransformation of steroids. Other members of this group are plant and animal pathogens. This review summarizes the current information available about the plasmids of corynebacteria. The emphasis is mainly on the small plasmids, which have been used for construction of vectors for expression of genes in these bacteria. Moreover, considerable information is now available on their nucleotide sequence, gene organization and modes of replication, which would make it possible to further manipulate these plasmids. Other plasmid properties, such as incompatibility and host range, are also discussed. Finally, use of these plasmids as cloning vectors for the expression of heterologous proteins using corynebacteria as hosts is also summarized to highlight the potential of these bacteria as hosts for recombinant DNA.