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1.
Mymensingh Med J ; 27(2): 424-428, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29769514

RESUMO

Cleidocranial dysplasia is a developmental anomaly of the skeleton and the teeth. This condition may be inherited and be transmitted as dominant characteristics in either gender, or may appear spontaneously. It presents with skeletal defects of several bones, such as partial or complete absence of clavicles, late closure of the fontanels, presence of open skull sutures and multiple wormian bones. The dental manifestations are mainly delayed exfoliation of primary teeth and delayed eruption of permanent teeth with multiple impacted supernumerary teeth. This case of a 20 year old girl is noteworthy to the dentist as it deals with clinical and radiological features (a high number of impacted and supernumerary teeth as well as brachycephaly, frontal bossing and hypermobility of shoulders) which may come handy in clinical practice.


Assuntos
Displasia Cleidocraniana , Dente Impactado , Dente Supranumerário , Displasia Cleidocraniana/complicações , Displasia Cleidocraniana/diagnóstico por imagem , Craniossinostoses , Feminino , Humanos , Radiografia , Erupção Dentária , Adulto Jovem
2.
Environ Monit Assess ; 187(1): 4180, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25487460

RESUMO

Cancer is a leading cause of death worldwide. Excluding the genetic factors, environmental factors, mainly the pollutants, have been implicated in the causation of the majority of cancers. Wastewater originated from health-care sectors such as hospitals may carry vast amounts of carcinogenic and genotoxic chemicals to surface waters or any other source of drinking water, if discharged untreated. Humans get exposed to such contaminants through a variety of ways including drinking water. The aim of the present study was, thus, to monitor the genotoxic and mutagenic potential of wastewaters from three big hospitals located in Jaipur (Rajasthan), India. One of them was operating an effluent treatment plant (ETP) for treatment of its wastewater and therefore both the untreated and treated effluents from this hospital were studied for their genotoxicity. Two short-term bacterial bioassays namely the Salmonella fluctuation assay and the SOS chromotest were used for the purpose. Results of fluctuation assay revealed the highly genotoxic nature of all untreated effluent samples with mutagenicity ratios (MR) up to 23.13 ± 0.18 and 42.25 ± 0.35 as measured with Salmonella typhimurium strains TA98 and TA100, respectively. As determined with the chromotest, all untreated effluents produced significant induction factors (IF) ranging from 3.29 ± 1.11 to 13.35 ± 3.58 at higher concentrations. In contrast, treated effluent samples were found to be slightly genotoxic in fluctuation test only with an MR = 3.75 ± 0.35 for TA100 at 10 % concentration. Overall, the results indicated that proper treatment of hospital wastewaters may render the effluents safe for disposal contrary to the untreated ones, possessing high genotoxic potential.


Assuntos
Monitoramento Ambiental/métodos , Hospitais/estatística & dados numéricos , Mutagênicos/análise , Águas Residuárias/química , Poluentes Químicos da Água/toxicidade , Bioensaio , Dano ao DNA , Índia , Testes de Mutagenicidade , Mutagênicos/toxicidade , Águas Residuárias/estatística & dados numéricos , Poluentes Químicos da Água/análise , Poluição Química da Água/estatística & dados numéricos
3.
Indian J Otolaryngol Head Neck Surg ; 56(4): 269-73, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23120094

RESUMO

A statistical study was carried out on SNHL in CSOM. The study group consisted of 1,828 patients suffering from CSOM who underwent surgery at our centre from 1982 to 2001, out of these 510 cases with unilateral CSOM were selected for this study by a strict selection criteria so as to eliminate covariables such as exposure to acoustic trauma, head injury, previous ear surgery and hereditary causes. The healthy ear served as control. We determined the average SNHL in relation to the age of onset, duration of disease, examining it in relation to other eventual aural complications such as cholesteatoma, ossicular chain erosion und otorrhea.On the basis of data obtained we observed consistent co-relation between severity of SNHL and duration of the disease, presence of cholesteatoma, ossicular erosion, attic and subtotal perforations. These findings suggest that more severe middle ear disease may result in SNHL and thus early intervention in cases of chronic suppurative Otitis media is desired.

4.
Proc Natl Acad Sci U S A ; 100(25): 14672-7, 2003 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-14638937

RESUMO

The glyoxalase pathway involving glyoxalase I (gly I) and glyoxalase II (gly II) enzymes is required for glutathione-based detoxification of methylglyoxal. We had earlier indicated the potential of gly I as a probable candidate gene in conferring salinity tolerance. We report here that overexpression of gly I+II together confers improved salinity tolerance, thus offering another effective strategy for manipulating stress tolerance in crop plants. We have overexpressed the gly II gene either alone in untransformed plants or with gly I transgenic background. Both types of these transgenic plants stably expressed the foreign protein, and the enzyme activity was also higher. Compared with nontransformants, several independent gly II transgenic lines showed improved capability for tolerating exposure to high methylglyoxal and NaCl concentration and were able to grow, flower, and set normal viable seeds under continuous salinity stress conditions. Importantly, the double transgenic lines always showed a better response than either of the single gene-transformed lines and WT plants under salinity stress. Ionic measurements revealed higher accumulation of Na+ and K+ in old leaves and negligible accumulation of Na+ in seeds of transgenic lines as compared with the WT plants. Comparison of various growth parameters and seed production demonstrated that there is hardly any yield penalty in the double transgenics under nonstress conditions and that these plants suffered only 5% loss in total productivity when grown in 200 mM NaCl. These findings establish the potential of manipulation of the glyoxalase pathway for increased salinity tolerance without affecting yield in crop plants.


Assuntos
Engenharia Genética , Lactoilglutationa Liase/genética , Nicotiana/genética , Southern Blotting , Western Blotting , Produtos Agrícolas , Regulação da Expressão Gênica de Plantas , Íons , Modelos Químicos , Modelos Genéticos , Dados de Sequência Molecular , Fenótipo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase , Aldeído Pirúvico/química , Sais/farmacologia , Sementes/metabolismo , Cloreto de Sódio/farmacologia , Água/química
5.
Middle East J Anaesthesiol ; 17(2): 275-85, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-14503127

RESUMO

Preoperative airway assessment for prediction of difficult laryngoscopy and intubation was done using the modified Mallampati test and Wilson risk sum score in three hundred and seventy two obstetric patients undergoing elective as well as emergency Cesarean section under general anesthesia. 25 (6.7%) patients had laryngoscopy grade III or IV of whom 24 (6.4%) patients were difficult at tracheal intubation. Mallampati class III or IV predicted 15 of the 23 patients while Wilson risk sum score > or = 2 predicted 9 of the 14 patients in whom tracheal intubation was difficult. As a screening test for prediction of difficult intubation Wilson risk sum score was less sensitive (36%) but had almost same specificity (98.5%) and positive predictive value (64%) in comparison to modified Mallampati test (62.5%, 97.7% and 65% respectively). When used as a predictor of difficult laryngoscopy sensitivity, specificity and positive predictive value for modified Mallampati test were 60%, 97.6% and 65% respectively and for Wilson risk sum they were 36%, 98.5% and 64% respectively, but when both tests were combined as predictors (with either of tests positive) sensitivity improved to 100% while specificity was marginally decreased to 96.2% and positive predictive value (64.8%) remained almost the same. There was no significant association between age and laryngoscopy grade III or IV but there was significant (P < 0.01) relationship with weight and external laryngeal manipulation. The advantage of the above tests lies in, incorporating them into the preoperative protocol, rather than using them as sole predictors of difficult laryngoscopy and intubation.


Assuntos
Anestesia Obstétrica , Intubação Intratraqueal/métodos , Adolescente , Adulto , Feminino , Humanos , Laringoscopia , Gravidez , Sensibilidade e Especificidade
6.
Biotechniques ; 33(4): 830-2, 834, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12398192

RESUMO

We describe here a PCR-based "directional genome walking" protocol. The basic procedure for the amplification consists of two rounds of PCR. A primary PCR was performed, on the genomic DNA using a biotinylated primer specific to a known sequence in the genome along with four universal walker primers that were designed with partial degeneracy. The biotinylated primary PCR products were immobilized on streptavidin-linked paramagnetic beads. This step removed all nonspecific amplification products, and the purified template was used for the second PCR using a nested primer and the walker primer-2 to increase specificity. This technique is potentially useful for cloning promoter regions and has been successfully used to isolate 5'-flanking genomic regions of many cDNA clones previously isolated by us.


Assuntos
Passeio de Cromossomo , DNA de Plantas/química , Genoma de Planta , Reação em Cadeia da Polimerase/métodos , Sequência de Bases , Primers do DNA , Técnicas de Amplificação de Ácido Nucleico
7.
Water Sci Technol ; 44(2-3): 351-8, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11548005

RESUMO

The release of depolymerization products of lignin during the degradation of lignocellulsic material under sulfate reducing condition was investigated. In addition, we investigated the fate of the most common (beta-O-4) link present in lignin under sulfate reducing condition, using a lignin model compound. The method of investigation was based on the selective inhibition of microbial uptake of released aromatic phenolic compounds, depolymerization product of lignin, by toluene. Eight different aromatic phenolic compounds were identified. Until day 17 only 3 phenolic compounds were regularly detected, thereafter 7 aromatic phenolic compounds could be regularly identified. The accumulation of identified phenolic acid was not linear with time. The lignin model compound was completely degraded within 13 days when either Avicel cellulose or newspaper was present as alternate source of carbon. On the other hand when lignin model compound was present as the sole source of carbon, it took more than 22 days for its complete degradation. But in either case complete degradation of lignin model compound was observed. Four degradation byproducts of lignin model compound were identified, but the two most significant compounds identified were vanillic acid and 3-methoxy-4-hydroxy benzene propionic acid. The GC/MS analysis of the degradation by products of lignin model compound indicated that beta-O-4 link was cleaved under sulfate reducing condition and the presence of additional carbon source enhanced this process.


Assuntos
Lignina/metabolismo , Modelos Químicos , Sulfatos/química , Cromatografia Gasosa-Espectrometria de Massas , Hidroxibenzoatos/química , Lignina/química , Oxirredução , Eliminação de Resíduos
8.
J Biol Chem ; 276(16): 12660-6, 2001 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-11152678

RESUMO

We examined the biosynthesis and post-translational processing of the brain-derived neurotrophic factor precursor (pro-BDNF) in cells infected with a pro-BDNF-encoding vaccinia virus. Metabolic labeling, immunoprecipitation, and SDS-polyacrylamide gel electrophoresis reveal that pro-BDNF is generated as a 32-kDa precursor that is N-glycosylated and glycosulfated on a site, within the pro-domain. Some pro-BDNF is released extracellularly and is biologically active as demonstrated by its ability to mediate TrkB phosphorylation. The precursor undergoes N-terminal cleavage within the trans-Golgi network and/or immature secretory vesicles to generate mature BDNF (14 kDa). Small amounts of a 28-kDa protein that is immunoprecipitated with BDNF antibodies is also evident. This protein is generated in the endoplasmic reticulum through N-terminal cleavage of pro-BDNF at the Arg-Gly-Leu-Thr(57)- downward arrow-Ser-Leu site. Cleavage is abolished when Arg(54) is changed to Ala (R54A) by in vitro mutagenesis. Blocking generation of 28-kDa BDNF has no effect on the level of mature BDNF and blocking generation of mature BDNF with alpha(1)-PDX, an inhibitor of furin-like enzymes, does not lead to accumulation of the 28-kDa form. These data suggest that 28-kDa pro-BDNF is not an obligatory intermediate in the formation of the 14-kDa form in the constitutive secretory pathway.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/biossíntese , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Hipocampo/metabolismo , Neurônios/metabolismo , Precursores de Proteínas/metabolismo , Processamento de Proteína Pós-Traducional , Sequência de Aminoácidos , Animais , Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/farmacologia , Células COS , Linhagem Celular , Chlorocebus aethiops , Embrião de Mamíferos , Glicosídeo Hidrolases , Glicosilação , Humanos , Camundongos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Neuroglia/metabolismo , Fosforilação , Precursores de Proteínas/biossíntese , Precursores de Proteínas/genética , Receptor trkB/efeitos dos fármacos , Receptor trkB/fisiologia , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/metabolismo , Transfecção , Vaccinia virus/genética
9.
J Indian Med Assoc ; 99(7): 382-4, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11881850

RESUMO

Vascular access for haemodialysis has seen many developments in recent times. Double lumen catheters introduced into wide bore veins have replaced the traditional Scribner shunt as temporary access thus reducing the complications and morbidity associated with it. Cuffed tunnelled internal jugular catheters and synthetic arteriovenous (AV) grafts usually made of polytetrafluoroethylene are the new additions to the vascular access armamentarium, but the AV fistula introduced in 1966 still remains the life-line for chronic haemodialysis patient. However, in elderly and diabetic patients, synthetic AV grafts are beneficial. The added advantage of synthetic grafts is short maturation time and multiple potential access sites. Access failure in 80% cases is due to venous stenosis and thrombotic episodes while infections or other complications are there in 20% cases. The complications of vascular access are not only a major cause of morbidity in haemodialysis patients but a major cost for the end stage renal disease programme. In western countries, access related morbidity accounts for almost 25% of all hospital stays for end stage renal disease patients and may contribute to as much as 50% of all hospitalisation cost. Access salvage includes prospective monitoring and treatment of outflow stenosis. The direct intra-access measure of blood flow by ultrasound dilution and duplex colour flow Doppler technique is the ideal method detecting venous outflow stenosis; however, conventional and digital subtraction angiography has an advantage, that total vasculature and blood flow may be visualised. The various treatment modalities for outflow stenosis include use of percutaneous transluminal angioplasty, stents and surgical correction. The lyses of secondary thrombosis can be done by surgical, medical and mechanical thrombolysis. The various methods being used to prevent graft stenosis include use of dipyridamole and radiation. The gene therapy holds promises for the future.


Assuntos
Cateteres de Demora/efeitos adversos , Cateteres de Demora/normas , Diálise Renal/métodos , Falha de Equipamento , Segurança de Equipamentos , Feminino , Humanos , Falência Renal Crônica/terapia , Masculino , Prognóstico , Fatores de Risco
10.
Biodegradation ; 11(4): 229-37, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11432581

RESUMO

The initial decomposition rates of cellulose and hemicellulose were measured using toluene to specifically inhibit the microbial uptake of hydrolysis products during the degradation of newspaper under sulfate reducing and methane producing conditions. The amount of glucose and xylose accumulation in the first 2 weeks of incubation period was higher in the sulfate reducing condition compared to the methane producing condition. It was estimated that 28 and 6% of initially loaded cellulose in the sulfate reducing condition and the methane producing condition was hydrolyzed, respectively. Accordingly, the newspaper-cellulose hydrolysis rate constant was estimated to be 6.7 times higher in sulfate reducing condition than in methane producing condition. Based on the glucose accumulation patterns, when sulfate reducing bacteria (SRB) were inhibited by anthraquinone and molybdate (Na2MoO4), it may be suggested that SRB might have contributed to the hydrolysis of cellulose, while their effect on the hydrolysis of hemicellulose could not be elucidated.


Assuntos
Biotecnologia/métodos , Celulose/metabolismo , Metano/metabolismo , Polissacarídeos/metabolismo , Sulfatos/metabolismo , Glucose/metabolismo , Hidrólise , Jornais como Assunto , Oxirredução , Xilose/metabolismo
11.
J Neurosci ; 19(6): 2069-80, 1999 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-10066260

RESUMO

Nerve growth factor (NGF) is released through the constitutive secretory pathway from cells in peripheral tissues and nerves where it can act as a target-derived survival factor. In contrast, brain-derived neurotrophic factor (BDNF) appears to be processed in the regulated secretory pathway of brain neurons and secreted in an activity-dependent manner to play a role in synaptic plasticity. To determine whether sorting differences are intrinsic to the neurotrophins or reflect differences between cell types, we compared NGF and BDNF processing in cultured hippocampal neurons using a Vaccinia virus expression system. Three independent criteria (retention or release from cells after pulse-chase labeling, depolarization-dependent release, and immunocytochemical localization) suggest that the bulk of newly synthesized NGF is sorted into the constitutive pathway, whereas BDNF is primarily sorted into the regulated secretory pathway. Similar results occurred with AtT 20 cells, including those transfected with cDNAs encoding neurotrophin precursor-green fluorescent protein fusions. The NGF precursor, but not the BDNF precursor, is efficiently cleaved by the endoprotease furin in the trans-Golgi network (TGN). Blocking furin activity in AtT 20 cells with alpha1-PDX as well as increasing the expression of NGF precursor partially directed NGF into the regulated secretory pathway. Therefore, neurotrophins can be sorted into either the constitutive or regulated secretory pathways, and sorting may be regulated by the efficiency of furin cleavage in the TGN. This mechanism may explain how neuron-generated neurotrophins can act both as survival factors and as neuropeptides.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Hipocampo/metabolismo , Fatores de Crescimento Neural/metabolismo , Neurônios/metabolismo , Animais , Eletrofisiologia , Furina , Hipocampo/citologia , Hipocampo/fisiologia , Imuno-Histoquímica , Camundongos/embriologia , Neurônios/fisiologia , Precursores de Proteínas/metabolismo , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Subtilisinas/farmacologia , Distribuição Tecidual
12.
J Neurosci ; 17(20): 7754-62, 1997 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-9315897

RESUMO

Schwann cells express low levels of myelin proteins in the absence of neurons. When Schwann cells and neurons are cultured together the production of myelin proteins is elevated, and myelin is formed. For peripheral myelin protein 22 (PMP22), the exact amount of protein produced is critical, because peripheral neuropathies result from its underexpression or overexpression. In this study we examined the effect of neurons on Schwann cell PMP22 production in culture and in peripheral nerve using metabolic labeling and pulse-chase studies as well as immunocytochemistry. Most of the newly synthesized PMP22 in Schwann cells is rapidly degraded in the endoplasmic reticulum. Only a small proportion of the total PMP22 acquires complex glycosylation and accumulates in the Golgi compartment. This material is translocated to the Schwann cell membrane in detectable amounts only when axonal contact and myelination occur. Myelination does not, however, alter the rapid turnover of PMP22 in Schwann cells. PMP22 may therefore be a unique myelin protein in that axonal contact promotes its insertion into the Schwann cell membrane and myelin without altering its rapid turnover rate within the cell.


Assuntos
Proteínas da Mielina/metabolismo , Bainha de Mielina/metabolismo , Neurônios/fisiologia , Nervo Isquiático/metabolismo , Animais , Transporte Biológico/fisiologia , Células Cultivadas , Técnicas de Cocultura , Retículo Endoplasmático/metabolismo , Glicosilação , Homeostase , Imuno-Histoquímica , Ratos , Ratos Sprague-Dawley , Células de Schwann/citologia , Células de Schwann/metabolismo , Nervo Isquiático/citologia , Fatores de Tempo
13.
J Histochem Cytochem ; 45(6): 795-804, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9199665

RESUMO

Nerve growth factor (NGF) in mouse submandibular glands (SGs) is generated from a 35-kD precursor by proteolytic enzymes that have yet to be identified. Prohormone convertases (PCs) cleave the NGF precursor in vitro, and in this study we questioned whether PCs could process salivary NGF in vivo. mRNA coding for PC2 (but not PC1) was detected on Northern blots of SG mRNA and also by in situ hybridization within parasympathetic neurons of intralobular ganglia. Northern blot and in situ hybridization analyses also detect mRNA coding for furin. In SGs of male mice, furin mRNA levels are high at birth and remain high throughout development. In glands from female mice, levels decline during postnatal development and are lower in adults than in newborns. Immunocytochemistry detects furin immunoreactivity in pro-acinar and ductal cells of glands from newborn and pubescent mice. In glands of adults, furin immunoreactivity is detectable in acinar cells but highest levels are present in NGF-containing granular convoluted tubule cells. These data, taken together with those from previous studies, suggest that furin is a candidate processing enzyme for NGF in mouse submandibular glands.


Assuntos
Fatores de Crescimento Neural/análise , Glândula Submandibular/enzimologia , Subtilisinas/análise , Animais , Northern Blotting , Western Blotting , Feminino , Furina , Imuno-Histoquímica , Hibridização In Situ , Masculino , Camundongos , Camundongos Endogâmicos BALB C , RNA Mensageiro/análise , Subtilisinas/genética
14.
J Biol Chem ; 272(14): 8837-40, 1997 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-9082996

RESUMO

The mRNA encoding brain-derived neurotrophic factor (BDNF) is widely distributed in central nervous system neurons, including in hippocampus and cortex. However, little is known about the physiology of BDNF protein within neurons, including how it is processed or packaged and the mechanisms that control its release. In this study, we have used antibodies to monitor the subcellular distribution of BDNF in cortical extracts from adult rats treated with kainic acid. BDNF immunoreactivity is elevated in rat cortex 12 h after kainic acid treatment. The protein is enriched in a vesicular fraction isolated from lysed synaptosomes, its distribution being similar to that of synaptotagmin, which is associated with synaptic vesicles and large dense core vesicles at nerve terminals. The vesicular pool of BDNF is digested by proteinase K only in the presence of Triton X-100 suggesting localization of BDNF in membrane fractions. Immunocytochemistry detects diffuse and punctate BDNF staining within cell bodies and processes of cortical neurons from kainic acid-treated rats, as well as in mossy fiber terminals of rat hippocampus. Taken together, these data show that BDNF can accumulate axonally within a vesicular compartment of brain neurons. Results support the idea that endogenous BDNF may be transported anterogradely and released by regulated secretory mechanisms.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/análise , Córtex Cerebral/química , Sinaptossomos/química , Animais , Western Blotting , Detergentes/farmacologia , Endopeptidase K/metabolismo , Agonistas de Aminoácidos Excitatórios/farmacologia , Ácido Caínico/farmacologia , Octoxinol/farmacologia , RNA Mensageiro/metabolismo , Ratos , Vesículas Sinápticas/química
15.
Biochem J ; 314 ( Pt 3): 951-60, 1996 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-8615794

RESUMO

In order to define the enzymes responsible for the maturation of the precursor of nerve growth factor (proNGF), its biosynthesis and intracellular processing by the pro-protein convertases furin, PC1, PC2, PACE4, PC5 and the PC5 isoform PC5/6-B were analysed using the vaccinia virus expression system in cells containing a regulated and/or a constitutive secretory pathway. Results demonstrate that in both cell types furin, and to a lesser extent PACE4 and PC5/6-B, are the best candidate proNGF convertases. Furthermore, two processed NGF forms of 16.5 and 13.5 kDa were evident in constitutively secreting cell lines such as LoVo and BSC40 cells, whereas only the 13.5 kDa form was observed in AtT20 cells, which contain secretory granules. Both forms display the same N-terminal sequence as mature NGF, and were also produced following site-directed mutagenesis of the C-terminal Arg-Arg sequence of NGF into Ala-Ala, suggesting that the difference between them is not at the C-terminus. Co-expression of proNGF with furin and either chromogranin B or secretogranin II (but not chromogranin A) in BSC40 cells eliminated the 16.5 kDa form. Data also show that N-glycosylation of the pro-segment of proNGF and trimming of the oligosaccharide chains are necessary for the exit of this precursor from the endoplasmic reticulum and its eventual processing and secretion. Sulphate labelling experiments demonstrated that proNGF is processed into mature NGF following the arrival of the precursor in the trans-Golgi network. This comparative study shows that the three candidate mammalian subtilisin/kexin-like convertases identified process proNGF into NGF and that the nature of the final processed products is dependent on the intracellular environment.


Assuntos
Fator de Crescimento Neural , Fatores de Crescimento Neural/metabolismo , Precursores de Proteínas/metabolismo , Processamento de Proteína Pós-Traducional , Serina Endopeptidases/metabolismo , Subtilisinas/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Linhagem Celular , Furina , Glicosídeo Hidrolases , Humanos , Mamíferos , Camundongos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Fatores de Crescimento Neural/biossíntese , Oligodesoxirribonucleotídeos , Plasmídeos , Pró-Proteína Convertases , Precursores de Proteínas/biossíntese , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/metabolismo , Transfecção , Vaccinia virus
16.
FEBS Lett ; 379(3): 247-50, 1996 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-8603699

RESUMO

In order to define the enzymes responsible for the maturation of the precursors of brain-derived neurotrophic factor (proBDNF) and neurotrophin-3 (proNT3), we have analysed their biosynthesis and intracellular processing by the proprotein convertases furin, PC1, PC2, PACE4, PC5 and its isoform PC5/6-B. In these studies, we utilized a vaccinia virus expression system in either BSC40 or the furin activity-deficient LoVo cells. Results demonstrated that in both cells furin and, to a lesser extent, PACE4 and PC5/6-B effectively process proBDNF and proNT3. Furthermore, we have determined that human proNT3 is sulfated, suggesting that processing of proNT3 occurs following the arrival of the precursor to the Trans Golgi Network.


Assuntos
Precursores Enzimáticos/metabolismo , Fatores de Crescimento Neural/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo , Linhagem Celular , Furina , Humanos , Camundongos , Neurotrofina 3 , Pró-Proteína Convertase 5 , Pró-Proteína Convertases , Processamento de Proteína Pós-Traducional , Serina Endopeptidases/metabolismo , Subtilisinas/metabolismo , Células Tumorais Cultivadas
17.
J Biol Chem ; 269(41): 25795-808, 1994 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-7929285

RESUMO

Mutations affecting the peripheral myelin protein-22 (PMP22) gene have been shown to be associated with inherited peripheral neuropathies. To provide the molecular basis for the analysis of such mutations, we have cloned and characterized the human PMP22 gene. It spans approximately 40 kilobases and contains four coding exons. Detailed analysis of its 5'-flanking region suggested the presence of two alternatively transcribed, but untranslated exons. Mapping of separate PMP22 mRNA transcription initiation sites to each of these exons indicates that PMP22 expression is regulated by two alternatively used promoters. In support of this hypothesis, both putative promoter sequences demonstrated the ability to drive expression of reporter genes in transfection experiments. Furthermore, the structures of the 5'-portions of the PMP22 genes appear to be identical in rat and human, supporting the biological significance of the observed arrangement of regulatory regions. The relative expression of the alternative PMP22 transcripts is tissue-specific, and high levels of the exon 1A-containing transcript are tightly coupled to myelin formation. In contrast, exon 1B-containing transcripts are predominant in non-neural tissues and in growth-arrested primary fibroblasts. Interestingly, although a strong upregulation of PMP22 mRNA was observed in cultured Schwann cells in the presence of the adenylate cyclase activator forskolin under various culture conditions, the regulation of the different PMP22 mRNA species did not mimic the regulation that occurs during myelin formation in vivo. The observed regulation of the PMP22 gene by a complex molecular mechanism is consistent with the proposed dual role of PMP22 in neural and non-neural tissue.


Assuntos
Processamento Alternativo , Proteínas da Mielina/genética , Regiões Promotoras Genéticas/genética , RNA Mensageiro/biossíntese , Transcrição Gênica , Processamento Alternativo/efeitos dos fármacos , Animais , Sequência de Bases , Células Cultivadas , Clonagem Molecular , Colforsina/farmacologia , Cricetinae , Fibroblastos/metabolismo , Genoma Humano , Neuropatia Hereditária Motora e Sensorial/genética , Humanos , Dados de Sequência Molecular , Proteínas da Mielina/biossíntese , Regeneração Nervosa/fisiologia , Ratos , Células de Schwann/metabolismo , Nervo Isquiático/crescimento & desenvolvimento , Análise de Sequência de DNA , Especificidade da Espécie , Distribuição Tecidual
18.
J Biol Chem ; 268(14): 10372-9, 1993 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-8486695

RESUMO

Peripheral myelin protein, 22 kDa (PMP22), is a myelin molecule associated with Schwann cells in peripheral nerves (Snipes, G. J., Suter, U., Welcher, A. A., and Shooter, E. M. (1992) J. Cell Biol. 117, 225-238). Mutations affecting the PMP22 gene have been implicated in the trembler mutation in mice (Suter, U., Welcher, A. A., Ozcelik, T., Snipes, G. J., Kosaras, B., Francke, U., Billings-Gagliardi, S., Sidman, R. L., and Shooter, E. M. (1992) Nature 356, 241-244; Suter, U., Moskow, J. J., Welcher, A. A., Snipes, G. J., Kosaras, B., Sidman, R. L., Buchberg, A. M., and Shooter, E. M. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 4382-4386) and Charcot-Marie-Tooth Disease in humans (Patel, P. I., Roa, B. B., Welcher, A. A., Schoener-Scott, R., Trask, B. J., Pentao, L., Snipes, G. J., Garcia, C. A., Francke, U., Shooter, E. M., Lupski, J. R., and Suter, U. (1992) Nature genet. 1, 159-165). In this report, we have studied PMP22 production in cultured rat Schwann cells. Schwann cells contain a 1.8-kilobase mRNA transcript coding for PMP22, and its production is up-regulated in vitro by forskolin. Metabolic labeling combined with immunoprecipitation methods using antibodies raised against synthetic peptides of PMP22 reveal that Schwann cells generate the protein from an 18-kDa precursor form which is post-translationally modified by N-linked glycosylation. A second molecule (molecular mass, 48 kDa) that reacted with PMP22 antibodies was also detected in Schwann cells but is not related chemically to PMP22 as determined by pulse-chase labeling. Metabolic labeling of rat sciatic nerve and Western blot analyses of purified rat sciatic nerve myelin reveal that deglycosylation of PMP22 gives rise to an 18-kDa protein similar in size to that in Schwann cells. These results indicate that cultured Schwann cells may provide a good model in which to investigate the production and function of PMP22 and to establish the cellular basis for the protein's involvement in inherited peripheral neuropathies.


Assuntos
Proteínas da Mielina/biossíntese , Células de Schwann/metabolismo , Nervo Isquiático/metabolismo , Sequência de Aminoácidos , Animais , Animais Recém-Nascidos , Autorradiografia , Western Blotting , Células Cultivadas , Colforsina/farmacologia , Cinética , Metionina/metabolismo , Dados de Sequência Molecular , Proteínas da Mielina/análise , Peptídeos/síntese química , Peptídeos/imunologia , Ratos , Ratos Sprague-Dawley , Células de Schwann/efeitos dos fármacos , Radioisótopos de Enxofre , Fatores de Tempo , Tunicamicina/farmacologia
19.
J Neurosci ; 12(7): 2504-15, 1992 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1377231

RESUMO

Non-neuronal cells of peripheral nerve respond to axonal injury with a series of cellular changes that facilitate neuronal regeneration. To characterize the potential role of the epidermal growth factor (EGF) family of proteins in this response, we monitored the expression of EGF receptor mRNA and protein in the injured rat sciatic nerve. EGF receptor mRNA is synthesized in both primary cultured fibroblasts and Schwann cells, and Schwann cells express EGF receptor-like immunoreactivity. In situ hybridization and immunocytochemistry revealed that EGF receptor mRNA and protein are expressed in Schwann cells and fibroblasts of the sciatic nerve in vivo, and that receptor levels increase following nerve injury. Thirty-six hours postlesion, EGF receptors were expressed in gradients along the nerve both proximal and distal to the lesion, with the highest levels localized adjacent to the transection site. By 72 hr, receptor levels were maintained in a gradient in the proximal segment, but were uniformly increased throughout the portions of the distal segment that were analyzed. These changes were similar to those observed for low-affinity NGF receptor mRNA and protein, with transection causing increased expression in both Schwann cells and fibroblasts. Northern blots confirmed that primary cultured fibroblasts express low-affinity NGF receptor mRNA. To determine whether spatiotemporal gradients were a general characteristic of the nerve injury response, we monitored expression of the mRNA encoding the major myelin protein P0. Levels of P0 mRNA decreased initially in cells immediately adjacent to the transection site and, by 72 hr, were uniformly decreased throughout the distal segment. These data suggest that members of the EGF family of proteins may play a role in the peripheral nerve response to injury, and demonstrate a generalized gradient of cellular responses that commence at the transection site and progress distally in the nerve in the absence of intact axons.


Assuntos
Receptores ErbB/biossíntese , RNA Mensageiro/metabolismo , Células de Schwann/fisiologia , Nervo Isquiático/fisiologia , Fenômenos Fisiológicos da Pele , Animais , Elementos Antissenso (Genética) , Northern Blotting , Células Cultivadas , Receptores ErbB/análise , Receptores ErbB/genética , Feminino , Fibroblastos/fisiologia , Imunoglobulina G , Imuno-Histoquímica , Proteína P0 da Mielina , Proteínas da Mielina/análise , RNA/genética , RNA/isolamento & purificação , Sondas RNA , RNA Mensageiro/análise , RNA Mensageiro/genética , Ratos , Ratos Endogâmicos , Nervo Isquiático/lesões , Fatores de Tempo
20.
Radiobiol Radiother (Berl) ; 30(2): 167-72, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2473485

RESUMO

Pregnant mice were continuously irradiated (0.3 microCi (11.1 kBq)/ml of drinking HTO) from the 16th day post coitum. Biochemical studies were made on liver of mice 1 to 6 weeks post partum. RNA content increased significantly at 1 and 2 weeks while it decreased at later intervals. DNA concentration decreased till 4 weeks but at 5th and 6th week it increased by 3.70% and 22.64%, respectively. Protein content showed biphasic pattern whereas, cholesterol concentration increased after irradiation.


Assuntos
Fígado/efeitos da radiação , Efeitos Tardios da Exposição Pré-Natal , Trítio , Água , Animais , Colesterol/metabolismo , DNA/metabolismo , Feminino , Fígado/crescimento & desenvolvimento , Fígado/metabolismo , Camundongos , Gravidez , Proteínas/metabolismo , RNA/metabolismo
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