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1.
Membranes (Basel) ; 14(9)2024 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-39330528

RESUMO

Pre-concentration can reduce the total production costs in the pharmaceutical industry. Organic solvent forward osmosis (OSFO) is a suitable pre-concentration method because of its nonthermal nature, low capital cost, and potential for achieving high-degree concentrations. In a previous study, we first demonstrated a high-degree OSFO concentration. Sucrose octaacetate (SoA) in MeOH was concentrated to 52 wt% using polyethylene glycol (PEG)-400 as the osmotic agent, but the concentrated solution had a concentration of 17% PEG-400 because of the reverse solute flux. This result does not meet the typical purity standards required for pharmaceutical production, indicating the need to determine a suitable osmotic agent that can be used for practical purposes. This study proposes a practical osmotic agent for OSFO pre-concentration. First, osmotic agents were screened from a practical perspective. Polypropylene glycol (PPG)-400 was selected, owing to its low toxicity, good solubility, and low viscosity. Subsequently, the OSFO concentration was demonstrated using PPG-400 as the osmotic agent. SoA in MeOH was concentrated from 9.4 wt% to 48 wt%. The final feed solution contained only 0.04 wt% PPG-400. This result is the first demonstration of successful pharmaceutical pre-concentration using OSFO that satisfies the typical purity requirement in pharmaceutical production.

2.
RSC Adv ; 14(29): 20786-20796, 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38952929

RESUMO

A tough ion gel membrane containing a CO2-philic ionic liquid, 1-ethyl-3-methylimidazolium tricyanomethanide ([Emim][C(CN)3]), was developed, and its CO2 permeation properties were evaluated under humid conditions at elevated temperatures. Pebax 1657, which is a diblock copolymer composed of a polyamide block and a polyethylene oxide block, was used as the gel network of the ion gel membrane to prepare a tough ion gel with good ionic liquid-holding properties. The polyamide block formed a semicrystalline structure in [Emim][C(CN)3] to toughen the ion gel membrane via an energy dissipation mechanism. The polyethylene oxide block exhibited good compatibility with [Emim][C(CN)3] and contributed to the retention of the ionic liquid in the ion gel. The developed ion gel membrane showed a good CO2 separation performance of 1677 barrer CO2 permeability and 37 CO2/N2 permselectivity under humid conditions of 75% relative humidity at an elevated temperature of 50 °C, which corresponds to an exhaust gas from a coal-fired power plant.

3.
Heliyon ; 10(7): e29041, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38596133

RESUMO

Pollution of plastic waste in aquatic ecosystems in Ghana is of significant concern with potential adverse effects on food safety and ecosystem function. This study examined the abundance and distribution of microplastics (MPs) in freshwater biota samples namely: the African river prawn (Macrobrachium vollenhovenii), the Volta clam (Galatea paradoxa), Nile tilapia (Oreochromis niloticus), and sediment from the Volta Lake. Both biota and sediment samples were subjected to microscopic identification and FTIR analysis. In biota samples, the highest mean microplastic abundance of 4.7 ± 2.1 items per individual was found in the prawn, while the Nile tilapia recorded the least (2.8 ± 0.6 items per individual). A total of 398 microplastic particles were observed in sediment samples from the Volta Lake. Microfibers were the major plastic shapes identified in biota and sediment samples. We examined the relationship between microplastic abundance, biota size, and sediment properties. Despite the lack of statistical significance, microplastic shape, size, and polymer composition in assessed organisms mirrored those in the benthic sediment. Polyethylene, polypropylene, polyester, and polystyrene were the four dominant polymer types identified in the organisms and sediments. Although the estimated human exposure was relatively low compared with studies from other regions of the world, the presence of microplastics raises concern for the safety of fisheries products consumed by the general populace in the country. This research is essential for developing effective mitigation measures and tackling the wider effects of microplastic contamination on Ghana's freshwater ecosystems, particularly the Volta Lake.

4.
Kyobu Geka ; 77(2): 146-149, 2024 Feb.
Artigo em Japonês | MEDLINE | ID: mdl-38459865

RESUMO

A 58-year-old man was admitted to our hospital with fever and neck swelling after dental treatment. He was diagnosed with a cervical abscess and underwent cervical abscess drainage, but 1 week later he developed descending necrotizing mediastinitis and was referred to our department. He underwent mediastinal and pleural drainage, but neck abscess was recured, Re-debridment of the neck abscess resulted in bleeding from right subclavian vein. The bleeding was successfully stopped with TacoSeal after L-shaped sternotomyand dissection of sternocleidomostoid muscle.


Assuntos
Mediastinite , Traumatismos Torácicos , Masculino , Humanos , Pessoa de Meia-Idade , Mediastinite/etiologia , Mediastinite/cirurgia , Abscesso/diagnóstico por imagem , Abscesso/etiologia , Abscesso/cirurgia , Veia Subclávia/diagnóstico por imagem , Veia Subclávia/cirurgia , Desbridamento , Necrose/cirurgia , Drenagem/métodos
5.
Opt Express ; 31(23): 38494-38512, 2023 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-38017954

RESUMO

The Arctic Ocean (AO) is the most river-influenced ocean. Located at the land-sea interface wherein phytoplankton blooms are common, Arctic coastal waterbodies are among the most affected regions by climate change. Given phytoplankton are critical for energy transfer supporting marine food webs, accurate estimation of chlorophyll a concentration (Chl), which is frequently used as a proxy of phytoplankton biomass, is critical for improving our knowledge of the Arctic marine ecosystem and its response to the ongoing climate change. Due to the unique and complex bio-optical properties of the AO, efforts are still needed to obtain more accurate Chl estimates, especially for coastal waters with high colored detrital material (CDM) content. In this study, we optimized the the Garver-Siegel-Maritorena (GSM) algorithm, using an Arctic bio-optical dataset comprised of seven wavelengths (the original GSM wavelengths plus 625 nm). Results suggested that our tuned algorithm, denoted GSMA, outperformed an alternative AO GSM algorithm denoted AO.GSM, but the accuracy of Chl estimates was only improved by 8%. In addition, GSMA showed appreciable robustness when assessed using a satellite image and two non-Arctic coastal datasets.

6.
Water Res ; 246: 120716, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37837900

RESUMO

Ammoniacal nitrogen (NH4N) is a ubiquitous nitrogen pollutant found in wastewater, which could cause eutrophication and severe environmental stress. It is therefore necessary to manage NH4N by enrichment and recovery for potential reuse, as well as to regulate the amount of environmental discharge. Hybridization of membrane-based processes is an attractive option for further enhancing water and nutrient reclamation from waste streams; thus, in this present work, a hybrid osmotically assisted reverse osmosis (OARO) and reverse osmosis (RO) process was demonstrated for subsequent ammoniacal nitrogen enrichment and wastewater discharge management. Using a commercially-available cellulose triacetate membrane module, model and real wastewater containing approximately 4,000ppm NH4N were effectively dewatered and enriched to a final NH4N content of 40,300ppm. This corresponds to enrichment of around 10 times and approximately 90% pure water recovery. The effective combination of both processes resulted in high efficiency, as well as economical and energy-saving benefits, as shown by the process performance and our preliminary techno-economic analysis. The specific energy consumption of the hybrid process projected to operate at a capacity of 2,000 m3h-1 was determined to be 8.8kWh m-3, or 0.56kWh kg-1 NH4Cl removed/recovered for an initial feed solution containing around 15,300ppm NH4Cl. Hybrid OARO and RO operation was able to achieve satisfactory enrichment by the OARO process and obtaining clean water by the RO process. The hybrid OARO-RO process has shown great potential as a suitable end-stage membrane-based process for wastewater dewatering and NH4N enrichment and recovery toward a circular economy and environmental management, as well as clean water recovery.


Assuntos
Águas Residuárias , Purificação da Água , Nitrogênio , Purificação da Água/métodos , Osmose , Membranas Artificiais , Água , Eliminação de Resíduos Líquidos/métodos
7.
Small ; 19(33): e2300672, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37072832

RESUMO

Laminar membranes comprising graphene oxide (GO) and metal-organic framework (MOF) nanosheets benefit from the regular in-plane pores of MOF nanosheets and thus can support rapid water transport. However, the restacking and agglomeration of MOF nanosheets during typical vacuum filtration disturb the stacking of GO sheets, thus deteriorating the membrane selectivity. Therefore, to fabricate highly permeable MOF nanosheets/reduced GO (rGO) membranes, a two-step method is applied. First, using a facile solvothermal method, ZnO nanoparticles are introduced into the rGO laminate to stabilize and enlarge the interlayer spacing. Subsequently, the ZnO/rGO membrane is immersed in a solution of tetrakis(4-carboxyphenyl)porphyrin (H2 TCPP) to realize in situ transformation of ZnO into Zn-TCPP in the confined interlayer space of rGO. By optimizing the transformation time and mass loading of ZnO, the obtained Zn-TCPP/rGO laminar membrane exhibits preferential orientation of Zn-TCPP, which reduces the pathway tortuosity for small molecules. As a result, the composite membrane achieves a high water permeance of 19.0 L m-2  h-1  bar-1 and high anionic dye rejection (>99% for methyl blue).

8.
Water Res ; 230: 119567, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36621280

RESUMO

Domestic wastewater (DWW) contains a reservoir of nutrients, such as nitrogen, potassium, and phosphorus; however, emerging micropollutants (EMPs) hinder its applications in resource recovery. In this study, a novel class of nanofiltration (NF) membranes was developed; it enabled the efficient removal of harmful EMP constituents while preserving valuable nutrients in the permeate. Neutral (IM-N) and positively charged (IM-P) imidazole derivative compounds have been used to chemically functionalize pristine polyamide (PA) membranes to synchronously inhibit the hydrolysis of residual acyl chloride and promote their amination. Owing to their distinct properties, these IM modifiers can custom-build the membrane physicochemical properties and structures to benefit the NF process in DWW treatment. The electroneutral NF membrane exhibited ultrahigh solute-solute selectivity by minimizing the Donnan effects on ion penetration (K, N, and P ions rejection < 25%) while imposing remarkable size-sieving obstruction against EMPs (rejection ratio > 91%). Moreover, the hydrophilic IM-modifier synergistically led to enhanced water permeance of 9.2 L m-2 h-1 bar-1, reaching a 2-fold higher magnitude than that of the pristine PA membrane, along with excellent antifouling/antibacterial fouling properties. This study may provide a paradigm shift in membrane technology to convert wastewater streams into valuable water and nutrient resources.


Assuntos
Membranas Artificiais , Águas Residuárias , Cloretos , Nylons , Água , Imidazóis
9.
Soft Matter ; 18(25): 4725-4736, 2022 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-35703111

RESUMO

Constructing crosslinked polymer networks via reversible interactions is a promising approach to recover the mechanical strength of damaged gels. In addition, by designing effective reversible crosslinks, the mechanical strength of the gel can be enhanced through energy dissipation based on the destruction of the crosslinks by an applied force. In this study, we introduced zeolitic imidazole framework-8 nanoparticles (ZIF-8 NPs), which acted as multifunctional crosslinkers, to provide multipoint coordination bonding with a poly(N,N-dimethylacrylamide)-based polymer network in a gel containing an ionic liquid. The mechanical strength of the gel increased with an increase in the content of ZIF-8 NPs up to 6 wt%. It was confirmed that the energy loaded onto the gel was dissipated through the desorption of the polymer network from the surface of the ZIF-8 NPs. Owing to the reversible destruction and reconstruction of the coordinative crosslinking between the polymer network and ZIF-8 NPs, the mechanical strength of the damaged gel was almost fully recovered through annealing.

10.
Membranes (Basel) ; 11(8)2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34436351

RESUMO

Forward osmosis (FO) membrane process is expected to realize energy-saving seawater desalination. To this end, energy-saving water recovery from a draw solution (DS) and effective DS regeneration are essential. Recently, thermo-responsive DSs have been developed to realize energy-saving water recovery and DS regeneration. We previously reported that high-temperature reverse osmosis (RO) treatment was effective in recovering water from a thermo-responsive ionic liquid (IL)-based DS. In this study, to confirm the advantages of the high-temperature RO operation, thermo-sensitive IL-based DS was treated by an RO membrane at temperatures higher than the lower critical solution temperature (LCST) of the DS. Tetrabutylammonium 2,4,6-trimethylbenznenesulfonate ([N4444][TMBS]) with an LCST of 58 °C was used as the DS. The high-temperature RO treatment was conducted at 60 °C above the LCST using the [N4444][TMBS]-based DS-lean phase after phase separation. Because the [N4444][TMBS]-based DS has a significantly temperature-dependent osmotic pressure, the DS-lean phase can be concentrated to an osmotic pressure higher than that of seawater at room temperature (20 °C). In addition, water can be effectively recovered from the DS-lean phase until the DS concentration increased to 40 wt%, and the final DS concentration reached 70 wt%. From the results, the advantages of RO treatment of the thermo-responsive DS at temperatures higher than the LCST were confirmed.

11.
Intern Med ; 56(20): 2705-2710, 2017 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-28924114

RESUMO

Objective This study was performed to confirm the efficacy of long-interval cytapheresis on steroid-dependent ulcerative colitis (UC). Methods To discontinue steroids in patients with steroid-dependent UC, we previously designed a novel regimen of cytapheresis (CAP), which we termed "long-interval cytapheresis (LI-CAP)", in which CAP was performed as one session every two or three weeks and continued during the whole period of tapering steroid dosage. In this study, we performed LI-CAP therapy 20 times (11 male and 9 female; mean age 41.8 years) between April 2010 and April 2015 for 14 patients with steroid-dependent UC. We evaluated the effectiveness of LI-CAP by examining the improvement in Lichtiger's clinical activity index (CAI), the rate of clinical remission, and the rate of steroid discontinuation. We further examined the rate of sustained steroid-free clinical remission at 6 and 12 months after LI-CAP in patients who successfully discontinued steroid-use after LI-CAP. The primary endpoint was the rate of discontinuation of steroids after LI-CAP. Results The mean CAI score before LI-CAP (7.550) significantly decreased to 1.65 after LI-CAP (p<0.0001). The rate of clinical remission after LI-CAP was 80%. The rate of steroid discontinuation after LI-CAP was 60.0%. The mean dose of daily prednisolone was significantly decreased after LI-CAP (2.30 mg) compared with that before therapy (17.30 mg) (p=0.0003). The rate of sustained steroid-free clinical remission after LI-CAP was 66.7% at 6 months and 66.7% at 12 months. Conclusion We confirmed that LI-CAP has therapeutic effects on reducing the dosage and discontinuing steroids in patients with steroid-dependent UC.


Assuntos
Colite Ulcerativa/tratamento farmacológico , Citaferese/métodos , Esteroides/uso terapêutico , Adulto , Protocolos Clínicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prednisolona/uso terapêutico , Indução de Remissão , Esteroides/administração & dosagem , Resultado do Tratamento , Adulto Jovem
12.
Sci Rep ; 6: 29609, 2016 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-27387863

RESUMO

Extinctions within major pelagic groups (e.g., radiolarians and conodonts) occurred in a stepwise fashion during the last 15 Myr of the Triassic. Although a marked decline in the diversity of pelagic faunas began at the end of the middle Norian, the cause of the middle Norian extinction is uncertain. Here we show a possible link between the end-middle Norian radiolarian extinction and a bolide impact. Two palaeoenvironmental events occurred during the initial phase of the radiolarian extinction interval: (1) a post-impact shutdown of primary and biogenic silica production within a time span of 10(4)-10(5) yr, and (2) a sustained reduction in the sinking flux of radiolarian silica for ~0.3 Myr after the impact. The catastrophic collapse of the pelagic ecosystem at this time was probably the dominant factor responsible for the end-middle Norian conodont extinction.

13.
ISME J ; 9(4): 990-1002, 2015 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-25325383

RESUMO

Arctic Ocean microbial eukaryote phytoplankton form subsurface chlorophyll maximum (SCM), where much of the annual summer production occurs. This SCM is particularly persistent in the Western Arctic Ocean, which is strongly salinity stratified. The recent loss of multiyear sea ice and increased particulate-rich river discharge in the Arctic Ocean results in a greater volume of fresher water that may displace nutrient-rich saltier waters to deeper depths and decrease light penetration in areas affected by river discharge. Here, we surveyed microbial eukaryotic assemblages in the surface waters, and within and below the SCM. In most samples, we detected the pronounced SCM that usually occurs at the interface of the upper mixed layer and Pacific Summer Water (PSW). Poorly developed SCM was seen under two conditions, one above PSW and associated with a downwelling eddy, and the second in a region influenced by the Mackenzie River plume. Four phylogenetically distinct communities were identified: surface, pronounced SCM, weak SCM and a deeper community just below the SCM. Distance-decay relationships and phylogenetic structure suggested distinct ecological processes operating within these communities. In the pronounced SCM, picophytoplanktons were prevalent and community assembly was attributed to water mass history. In contrast, environmental filtering impacted the composition of the weak SCM communities, where heterotrophic Picozoa were more numerous. These results imply that displacement of Pacific waters to greater depth and increased terrigenous input may act as a control on SCM development and result in lower net summer primary production with a more heterotroph dominated eukaryotic microbial community.


Assuntos
Fitoplâncton/classificação , Água do Mar/microbiologia , Regiões Árticas , Biodiversidade , Clorofila/análise , Fenômenos Ecológicos e Ambientais , Meio Ambiente , Eucariotos/química , Eucariotos/classificação , Eucariotos/isolamento & purificação , Filogenia , Filogeografia , Fitoplâncton/química , Fitoplâncton/isolamento & purificação , Rios , Salinidade , Estações do Ano , Água do Mar/química
15.
Science ; 336(6087): 1408, 2012 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-22678359

RESUMO

Phytoplankton blooms over Arctic Ocean continental shelves are thought to be restricted to waters free of sea ice. Here, we document a massive phytoplankton bloom beneath fully consolidated pack ice far from the ice edge in the Chukchi Sea, where light transmission has increased in recent decades because of thinning ice cover and proliferation of melt ponds. The bloom was characterized by high diatom biomass and rates of growth and primary production. Evidence suggests that under-ice phytoplankton blooms may be more widespread over nutrient-rich Arctic continental shelves and that satellite-based estimates of annual primary production in these waters may be underestimated by up to 10-fold.


Assuntos
Eutrofização , Camada de Gelo , Fitoplâncton/crescimento & desenvolvimento , Regiões Árticas , Biomassa , Diatomáceas/crescimento & desenvolvimento , Luz , Nitratos/análise , Oceanos e Mares , Fotossíntese , Complexo de Proteína do Fotossistema II/análise , Água do Mar/química
16.
J Arthroplasty ; 27(9): 1629-35, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22552220

RESUMO

The purposes of this study were to evaluate the midterm clinical and radiographic results of total hip arthroplasty (THA) in patients with Crowe type IV developmental dysplasia and to evaluate whether low back pain would improve after THA. Eighteen consecutive patients (20 hips) were included in this study. The average age at the time of surgery was 58.5 years. The average follow-up was 10.2 years. The socket was placed at the level of the true acetabulum, and a femoral shortening osteotomy was performed. The average Harris hip score before surgery was improved from 56 to 85 points at the final follow-up. Revision was performed in 4 hips due to loosening of the femoral component in 1 hip and osteolysis in 3 hips. The midterm outcomes of THA in patients with Crowe type IV developmental dysplasia were satisfactory. The severity of low back pain was significantly reduced after THA.


Assuntos
Artroplastia de Quadril/métodos , Luxação Congênita de Quadril/cirurgia , Dor Lombar/prevenção & controle , Idoso , Distribuição de Qui-Quadrado , Feminino , Seguimentos , Luxação Congênita de Quadril/classificação , Luxação Congênita de Quadril/diagnóstico por imagem , Humanos , Dor Lombar/etiologia , Masculino , Pessoa de Meia-Idade , Osteotomia , Medição da Dor , Estudos Prospectivos , Radiografia , Reoperação , Taxa de Sobrevida , Resultado do Tratamento
17.
J Arthroplasty ; 27(5): 820.e17-9, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-21958938

RESUMO

A 61-year-old man who had undergone revision total hip arthroplasty in 2000 was evaluated at our clinic in 2008, 1 day after feeling an abnormal clicking sensation in his left hip. Radiographs showed a fracture of the alumina ceramic liner of his acetabular component. A second revision total hip arthroplasty was performed with a 28-mm highly crosslinked polyethylene acetabular liner and an alumina femoral head. Sixteen months after the second revision, the patient experience sudden-onset hip pain. Radiographs revealed a fatigue fracture of the neck of a displaced stem. Analysis by scanning electron microscopy of the surface of the retrieved alumina ceramic femoral head revealed no scratches or wear, but analysis of the highly crosslinked polyethylene socket revealed third-body wear, scratches, irregularly shaped dips, and white ceramic particles. Elemental analysis of the white particles by an x-ray microanalyzer revealed the presence of aluminum and oxygen.


Assuntos
Artralgia/etiologia , Artroplastia de Quadril/efeitos adversos , Prótese de Quadril , Falha de Prótese , Acetábulo/diagnóstico por imagem , Artralgia/diagnóstico por imagem , Cerâmica , Articulação do Quadril/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Desenho de Prótese , Radiografia , Reoperação
18.
Int J Plant Genomics ; : 27894, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18253463

RESUMO

Traditionally, organisms have been classified on the basis of their phenotype. Recently, genotype-based classification has become possible through the development of sequencing technology. However, it is still difficult to apply sequencing approaches to the analysis of a large number of species due to the cost and labor. In most biological fields, the analysis of complex systems comprising various species has become an important theme, demanding an effective method for handling a vast number of species. In this paper, we have demonstrated, using plants, fish, and insects, that genome profiling, a compact technology for genome analysis, can classify organisms universally. Surprisingly, in all three of the domains of organisms tested, the phylogenetic trees generated from the phenotype topologically matched completely those generated from the genotype. Furthermore, a single probe was sufficient for the genome profiling, thereby demonstrating that this methodology is universal and compact.

19.
Gan To Kagaku Ryoho ; 30(7): 951-5, 2003 Jul.
Artigo em Japonês | MEDLINE | ID: mdl-12894709

RESUMO

We used a new combination chemotherapy with nedaplatin (CDGP) and 5-fluorouracil (5-FU) in eleven fresh patients with oral squamous cell carcinomas. 5-FU was administered at a dose of 1,000 mg/body by continuous infusion for 24 hours on days 1 to 5. CDGP was administered at a dose of 80 or 100 mg/m2 by drip infusion for 120 minutes on day 5. The response rates of total (1- or 2-course) and 2-course group were 54. 5% and 83.3%, respectively. Adverse drug reactions were limited to two cases of grade 3 toxicity with anorexia. The combination chemotherapy with 5-FU and CDGP in place of cisplatin and 5-FU seemed to play an important role as neo-adjuvant chemotherapy for oral squamous cell carcinomas.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma de Células Escamosas/tratamento farmacológico , Neoplasias Bucais/tratamento farmacológico , Idoso , Esquema de Medicação , Feminino , Fluoruracila/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Compostos Organoplatínicos/administração & dosagem
20.
J Biochem ; 132(1): 127-34, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12097169

RESUMO

The differentiation of megakaryocytes into platelets is highly regulated by many cytokines and growth factors. PACE4 and furin are Ca(2+)-dependent serine endoproteases belonging to the subtilisin-like proprotein convertase (SPC) family. These enzymes are involved in the proteolytic activation of proteins that play essential roles in cell growth and differentiation. In this study, we examined the expression of PACE4 and furin during the differentiation of megakaryoblastic cell lines, Dami and HEL cells, induced by phorbol 12-myristate 13-acetate (PMA). PMA stimulates not only the expression of platelet-derived growth factor-B (PDGF-B) mRNA, but also PACE4 mRNA in these cell lines. The expression of PACE4 transcripts (both the PACE4A and PACE4C/CS isoforms) was upregulated more than 4-fold by PMA. Moreover, direct treatment with PDGF-BB also resulted in an increase in the level of PACE4 mRNA. Further, the effect of PDGF-BB on PACE4 expression was confirmed by promoter assay of the PACE4 gene. Although the furin mRNA level was increased by TGF-beta1 in Dami cells, it was not affected by PDGF-BB. These results indicate for the first time that PACE4 expression is specifically upregulated by PDGF-BB in differentiated megakaryoblasts, suggesting a unique role for PACE4 in platelet production.


Assuntos
Megacariócitos/enzimologia , Fator de Crescimento Derivado de Plaquetas/farmacologia , Serina Endopeptidases/biossíntese , Subtilisinas/biossíntese , Becaplermina , Northern Blotting , Inibidores Enzimáticos/farmacologia , Furina , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Humanos , Megacariócitos/efeitos dos fármacos , Megacariócitos/ultraestrutura , Regiões Promotoras Genéticas/efeitos dos fármacos , Pró-Proteína Convertases , Inibidores de Proteínas Quinases , Proteínas Proto-Oncogênicas c-sis , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Subtilisinas/genética , Acetato de Tetradecanoilforbol/análogos & derivados , Acetato de Tetradecanoilforbol/farmacologia , Transfecção , Fator de Crescimento Transformador beta/farmacologia , Fator de Crescimento Transformador beta1 , Regulação para Cima/efeitos dos fármacos
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