Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
SSM Qual Res Health ; 2: 100082, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35434698

RESUMO

Several suggestions have been made as to why Sweden's approach to managing the COVID-19 pandemic came to rely on a strategy based on voluntary measures. Two of the most prominent explanations for why the country chose a different strategy than many other countries have focused on micro- and macro-level factors, explaining the strategy either in terms of the psychologies of prominent actors or by pointing to particularities in Swedish constitutional law. Supported by a qualitative analysis using interviews and text analysis, we argue that the Swedish strategy cannot be understood without paying attention to the meso-level and the organizations that produced the strategy. Moreover, we argue that to understand why one of the central organizations in Swedish pandemic management, the Public Health Agency, came to favor certain interventions, one must investigate the culture of production inside the organization and how it created precedents that led the Agency to approach pandemic management with a focus on balancing current and future health risks.

2.
J Community Genet ; 4(2): 181-8, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22829113

RESUMO

Current developments in genetics and genomics entail a number of changes and challenges for society as new knowledge and technology become common in the clinical setting and in society at large. The relationship between genetics and ethics has been much discussed during the last decade, while the relationship between genetics and the political arena-with terms such as rights, distribution, expertise, participation and democracy-has been less considered. The purpose of this article is to demonstrate the connection between genetics and democracy. In order to do this, we delineate a notion of democracy that incorporates process as well as substance values. On the basis of this notion of democracy and on claims of democratisation in the science and technology literature, we argue for the importance of considering genetic issues in a democratic manner. Having established this connection between genetics and democracy, we discuss this relation in three different contexts where the relationship between genetics and democracy becomes truly salient: the role of expertise, science and public participation, and individual responsibility and distributive justice. As developments within genetics and genomics advance with great speed, the importance and use of genetic knowledge within society can be expected to grow. However, this expanding societal importance of genetics might ultimately involve, interact with, or even confront important aspects within democratic rule and democratic decision-making. Moreover, we argue that the societal importance of genetic development makes it crucial to consider not only decision-making processes, but also the policy outcomes of these processes. This argument supports our process and substance notion of democracy, which implies that public participation, as a process value, must be complemented with a focus on the effects of policy decisions on democratic values such as distributive justice.

3.
J Community Genet ; 3(2): 57-9, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22402986
4.
Toxicol Sci ; 122(2): 567-78, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21572096

RESUMO

DAS181 is a novel inhaled drug candidate blocking influenza virus (IFV) and parainfluenza virus (PIV) infections through removal of sialic acid receptors from epithelial surface of the respiratory tract. To support clinical development, a 28-day Good Laboratory Practices inhalation toxicology study was conducted in Sprague-Dawley rats. In this study, achieved average daily doses based on exposure concentrations were 0.47, 0.90, 1.55, and 3.00 mg/kg/day of DAS181 in a dry powder formulation. DAS181 was well tolerated at all dose levels, and there were no significant toxicological findings. DAS181 administration did not affect animal body weight, food consumption, clinical signs, ophthalmology, respiratory parameters, or organ weight. Gross pathology evaluations were unremarkable. Histological examination of the lungs was devoid of pulmonary tissue damage, and findings were limited to mild and transient changes indicative of exposure and clearance of a foreign protein. DAS181 did not show any cytotoxic effects on human and animal primary cells, including hepatocytes, skeletal muscle cells, osteoblasts, or respiratory epithelial cells. DAS181 did not cause direct or indirect hemolysis. A laboratory abnormality observed in the 28-day toxicology study was mild and transient anemia in male rats at the 3.00 mg/kg dose, which is an expected outcome of enhanced clearance of desialylated red blood cells resulting from systemic exposure with DAS181. Another laboratory observation was a transient dose-dependent elevation in alkaline phosphatase (ALP), which can be attributed to reduced ALP clearance resulting from increased protein desialylation due to DAS181 systemic exposure. These laboratory parameters returned to normal at the end of the recovery period.


Assuntos
Neuraminidase/farmacologia , Proteínas Recombinantes de Fusão/farmacologia , Fosfatase Alcalina/análise , Animais , Linhagem Celular , Avaliação Pré-Clínica de Medicamentos , Feminino , Hepatócitos/efeitos dos fármacos , Humanos , Exposição por Inalação , Pulmão/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Neuraminidase/toxicidade , Orthomyxoviridae/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes de Fusão/toxicidade , Testes de Toxicidade
5.
FASEB J ; 25(6): 1887-93, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21350118

RESUMO

Type 2 diabetes is highly prevalent in human populations, particularly in obese individuals, and is characterized by progressive pancreatic ß-cell dysfunction and insulin resistance. Most mammals, including Old World primates, express two major kinds of sialic acids, N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), typically found at the distal ends of glycoconjugate chains at the cell surface. Humans are uniquely unable to produce endogenous Neu5Gc due to an inactivating mutation in the CMP-Neu5Ac hydroxylase (CMAH) gene. The CMAH enzyme catalyzes the generation of CMP-Neu5Gc by the transfer of a single oxygen atom to the acyl group of CMP-Neu5Ac. Here, we show that mice bearing a human-like deletion of the Cmah gene exhibit fasting hyperglycemia and glucose intolerance following a high-fat diet. This phenotype is caused not by worsened insulin resistance but by compromised pancreatic ß-cell function associated with a 65% decrease in islet size and area and 50% decrease in islet number. Obese Cmah-null mice also show an ∼40% reduction in response to insulin secretagogues in vivo. These findings show that human evolution-like changes in sialic acid composition impair pancreatic ß-cell function and exacerbate glucose intolerance in mice. This may lend insight into the pathogenesis of type 2 diabetes in obese humans.


Assuntos
Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Células Secretoras de Insulina/enzimologia , Células Secretoras de Insulina/fisiologia , Oxigenases de Função Mista/genética , Obesidade/metabolismo , Animais , Arginina/farmacologia , Glicemia , Diabetes Mellitus Tipo 2/etiologia , Gorduras na Dieta/farmacologia , Glucose/farmacologia , Intolerância à Glucose/genética , Intolerância à Glucose/metabolismo , Hiperglicemia/genética , Hiperglicemia/metabolismo , Células Secretoras de Insulina/efeitos dos fármacos , Camundongos , Camundongos Knockout , Camundongos Obesos , Oxigenases de Função Mista/deficiência , Mutação , Obesidade/complicações , Obesidade/genética
6.
J Antimicrob Chemother ; 66(1): 15-28, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21097900

RESUMO

BACKGROUND: influenza viruses (IFVs) frequently achieve resistance to antiviral drugs, necessitating the development of compounds with novel mechanisms of action. DAS181 (Fludase), a sialidase fusion protein, may have a reduced potential for generating drug resistance due to its novel host-targeting mechanism of action. METHODS: IFV strains B/Maryland/1/59 and A/Victoria/3/75 (H3N2) were subjected to >30 passages under increasing selective pressure with DAS181. The DAS181-selected IFV isolates were characterized in vitro and in mice. RESULTS: despite extensive passaging, DAS181-selected viruses exhibited a very low level of resistance to DAS181, which ranged between 3- and 18-fold increase in EC(50). DAS181-selected viruses displayed an attenuated phenotype in vitro, as exhibited by slower growth, smaller plaque size and increased particle to pfu ratios relative to wild-type virus. Further, the DAS181 resistance phenotype was unstable and was substantially reversed over time upon DAS181 withdrawal. In mice, the DAS181-selected viruses exhibited no greater virulence than their wild-type counterparts. Genotypic and phenotypic analysis of DAS181-selected viruses revealed mutations in the haemagglutinin (HA) and neuraminidase (NA) molecules and also changes in HA and NA function. CONCLUSIONS: results indicate that resistance to DAS181 is minimal and unstable. The DAS181-selected IFV isolates exhibit reduced fitness in vitro, likely due to altered HA and NA functions.


Assuntos
Antivirais/farmacologia , Farmacorresistência Viral , Vírus da Influenza A/efeitos dos fármacos , Vírus da Influenza B/efeitos dos fármacos , Mutação , Proteínas Recombinantes de Fusão/farmacologia , Seleção Genética , Animais , Feminino , Genótipo , Humanos , Vírus da Influenza A/genética , Vírus da Influenza A/crescimento & desenvolvimento , Vírus da Influenza A/patogenicidade , Vírus da Influenza B/genética , Vírus da Influenza B/crescimento & desenvolvimento , Vírus da Influenza B/patogenicidade , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Orthomyxoviridae/patologia , Infecções por Orthomyxoviridae/virologia , Fenótipo , Inoculações Seriadas , Ensaio de Placa Viral , Virulência , Replicação Viral
7.
J Infect Dis ; 201(7): 1007-15, 2010 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-20170378

RESUMO

BACKGROUND: DAS181 (Fludase) is a sialidase fusion protein in clinical development as a broad-spectrum anti-influenza virus (IFV) therapeutic agent. Previous reports by other investigators have raised the concern that desialylation of airway epithelium might increase susceptibility to Streptococcus pneumoniae infection. METHODS: To address whether DAS181 would lead to an increased risk of pneumococcal infection, we tested S. pneumoniae colonization after DAS181 treatment of human A549 cells, healthy mice, and mice challenged with a lethal dose of IFV A/PR/8/34 (H1N1) or A/Victoria/3/75 (H3N2), followed by 10(4) cfu of S. pneumoniae (D39) on day 3 or day 7. DAS181 treatment was given 24-48 h after IFV challenge. RESULTS: DAS181 treatment did not increase S. pneumoniae colonization in vitro or in vivo in healthy animals. In IFV-infected mice, DAS181 prevented pneumonia and significantly prolonged survival and inhibited the IFV titer by > or = 3 logs. None of the treated animals showed enhanced S. pneumoniae colonization of the lung. In addition, opportunistic infections with Citrobacter species or Klebsiella species occurred only in mice receiving vehicle, not in animals treated with DAS181. CONCLUSIONS: These data indicate that DAS181 treatment does not exacerbate secondary bacterial infection in mice. DAS181 may reduce the risk of secondary bacterial infection by inhibiting IFV.


Assuntos
Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Infecções por Orthomyxoviridae/microbiologia , Infecções Pneumocócicas/prevenção & controle , Proteínas Recombinantes de Fusão/farmacologia , Streptococcus pneumoniae/crescimento & desenvolvimento , Animais , Antivirais/farmacologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Histocitoquímica , Humanos , Influenza Humana/tratamento farmacológico , Influenza Humana/metabolismo , Pulmão/microbiologia , Pulmão/virologia , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Orthomyxoviridae/tratamento farmacológico , Infecções Pneumocócicas/tratamento farmacológico , Infecções Pneumocócicas/virologia , Carga Viral/efeitos dos fármacos
8.
Viruses ; 2(8): 1766-1781, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21994706

RESUMO

While vaccines are the primary public health response to seasonal and pandemic flu, short of a universal vaccine there are inherent limitations to this approach. Antiviral drugs provide valuable alternative options for treatment and prophylaxis of influenza. Here, we will review drugs and drug candidates against influenza with an emphasis on the recent progress of a host-targeting entry-blocker drug candidate, DAS181, a sialidase fusion protein.

9.
PLoS One ; 4(11): e7788, 2009 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-19893747

RESUMO

BACKGROUND: The recent emergence of a novel pandemic influenza A(H1N1) strain in humans exemplifies the rapid and unpredictable nature of influenza virus evolution and the need for effective therapeutics and vaccines to control such outbreaks. However, resistance to antivirals can be a formidable problem as evidenced by the currently widespread oseltamivir- and adamantane-resistant seasonal influenza A viruses (IFV). Additional antiviral approaches with novel mechanisms of action are needed to combat novel and resistant influenza strains. DAS181 (Fludase) is a sialidase fusion protein in early clinical development with in vitro and in vivo preclinical activity against a variety of seasonal influenza strains and highly pathogenic avian influenza strains (A/H5N1). Here, we use in vitro, ex vivo, and in vivo models to evaluate the activity of DAS181 against several pandemic influenza A(H1N1) viruses. METHODS AND FINDINGS: The activity of DAS181 against several pandemic influenza A(H1N1) virus isolates was examined in MDCK cells, differentiated primary human respiratory tract culture, ex-vivo human bronchi tissue and mice. DAS181 efficiently inhibited viral replication in each of these models and against all tested pandemic influenza A(H1N1) strains. DAS181 treatment also protected mice from pandemic influenza A(H1N1)-induced pathogenesis. Furthermore, DAS181 antiviral activity against pandemic influenza A(H1N1) strains was comparable to that observed against seasonal influenza virus including the H274Y oseltamivir-resistant influenza virus. CONCLUSIONS: The sialidase fusion protein DAS181 exhibits potent inhibitory activity against pandemic influenza A(H1N1) viruses. As inhibition was also observed with oseltamivir-resistant IFV (H274Y), DAS181 may be active against the antigenically novel pandemic influenza A(H1N1) virus should it acquire the H274Y mutation. Based on these and previous results demonstrating DAS181 broad-spectrum anti-IFV activity, DAS181 represents a potential therapeutic agent for prevention and treatment of infections by both emerging and seasonal strains of IFV.


Assuntos
Antivirais/farmacologia , Vírus da Influenza A Subtipo H1N1/metabolismo , Neuraminidase/química , Proteínas Recombinantes de Fusão/farmacologia , Animais , Brônquios/metabolismo , Cães , Feminino , Humanos , Influenza Humana/tratamento farmacológico , Rim/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Microscopia de Fluorescência/métodos , Oseltamivir/farmacologia , Proteínas Recombinantes de Fusão/química
10.
PLoS One ; 4(11): e7838, 2009 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-19893749

RESUMO

Antiviral drug resistance for influenza therapies remains a concern due to the high prevalence of H1N1 2009 seasonal influenza isolates which display H274Y associated oseltamivir-resistance. Furthermore, the emergence of novel H1N1 raises the potential that additional reassortments can occur, resulting in drug resistant virus. Thus, additional antiviral approaches are urgently needed. DAS181 (Fludase), a sialidase fusion protein, has been shown to have inhibitory activity against a large number of seasonal influenza strains and a highly pathogenic avian influenza (HPAI) strain (H5N1). Here, we examine the in vitro activity of DAS181 against a panel of 2009 oseltamivir-resistant seasonal H1N1 clinical isolates. The activity of DAS181 against nine 2009, two 2007, and two 2004 clinical isolates of seasonal IFV H1N1 was examined using plaque number reduction assay on MDCK cells. DAS181 strongly inhibited all tested isolates. EC50 values remained constant against isolates from 2004, 2007, and 2009, suggesting that there was no change in DAS181 sensitivity over time. As expected, all 2007 and 2009 isolates were resistant to oseltamivir, consistent with the identification of the H274Y mutation in the NA gene of all these isolates. Interestingly, several of the 2007 and 2009 isolates also exhibited reduced sensitivity to zanamivir, and accompanying HA mutations near the sialic acid binding site were observed. DAS181 inhibits IFV that is resistant to NAIs. Thus, DAS181 may offer an alternative therapeutic option for seasonal or pandemic IFVs that become resistant to currently available antiviral drugs.


Assuntos
Influenza Humana/virologia , Neuraminidase/antagonistas & inibidores , Neuraminidase/metabolismo , Orthomyxoviridae/metabolismo , Oseltamivir/farmacologia , Proteínas Recombinantes de Fusão/farmacologia , Animais , Antivirais/farmacologia , Sítios de Ligação , Células CACO-2 , Proliferação de Células , Cães , Humanos , Influenza Humana/metabolismo , Mutação , Ácido N-Acetilneuramínico/química , Zanamivir/farmacologia
11.
Phys Chem Chem Phys ; 11(1): 133-41, 2009 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-19081916

RESUMO

Three new sensitizers for photoelectrochemical solar cells were synthesized consisting of a triphenylamine donor, a rhodanine-3-acetic acid acceptor and a polyene connection. The conjugation length was systematically increased, which resulted in two effects: first, it led to a red-shift of the optical absorption of the dyes, resulting in an improved spectral overlap with the solar spectrum. Secondly, the oxidation potential decreased systematically. The excited state levels were, however, calculated to be nearly stationary. The experimental trends were in excellent agreement with density functional theory (DFT) computations. The photovoltaic performance of this set of dyes as sensitizers in mesoporous TiO2 solar cells was investigated using electrolytes containing the iodide/triiodide redox couple. The dye with the best absorption characteristics showed the poorest solar cell efficiency, due to losses by recombination of electrons in TiO2 with triiodide. Addition of 4-tert butylpyridine to the electrolyte led to a strongly reduced photocurrent for all dyes due to a reduced electron injection efficiency, caused by a 0.15 V negative shift of the TiO2 conduction band potential.

12.
Proc Natl Acad Sci U S A ; 105(48): 18936-41, 2008 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-19017806

RESUMO

Patients with cancer have circulating heterophile antibodies that agglutinate animal red cells via recognition of the mammalian cell surface sialic acid N-glycolylneuraminic acid (Neu5Gc), which was long considered an oncofetal antigen in humans. However, humans are genetically deficient in Neu5Gc production and instead metabolically accumulate Neu5Gc from dietary sources, particularly red meats and milk products. Moreover, mice with a human-like defect showed no alternate pathway for Neu5Gc synthesis and even normal humans express anti-Neu5Gc antibodies. We show here that human tumors accumulate Neu5Gc that is covalently attached to multiple classes of glycans. The paradox of human tumor Neu5Gc accumulation in the face of circulating anti-Neu5Gc antibodies was hypothesized to be due to facilitation of tumor progression by the resulting low-grade chronic inflammation. Indeed, murine tumors expressing human-like levels of Neu5Gc show accelerated growth in syngeneic mice with a human-like Neu5Gc deficiency, coincident with the induction of anti-Neu5Gc antibodies and increased infiltration of inflammatory cells. Transfer of polyclonal monospecific syngeneic mouse anti-Neu5Gc serum also enhanced growth of transplanted syngeneic tumors bearing human-like levels of Neu5Gc, with tumors showing evidence for antibody deposition, enhanced angiogenesis and chronic inflammation. These effects were suppressed by a cyclooxygenase-2 inhibitor, a drug type known to reduce human carcinoma risk. Finally, affinity-purified human anti-Neu5Gc antibodies also accelerate growth of Neu5Gc-containing tumors in Neu5Gc-deficient mice. Taken together, the data suggest that the human propensity to develop diet-related carcinomas is contributed to by local chronic inflammation, resulting from interaction of metabolically-accumulated dietary Neu5Gc with circulating anti-Neu5Gc antibodies.


Assuntos
Anticorpos Heterófilos/sangue , Carcinoma , Dieta , Inflamação/imunologia , Ácidos Neuramínicos/imunologia , Animais , Anticorpos Heterófilos/imunologia , Carcinoma/sangue , Carcinoma/imunologia , Carcinoma/patologia , Ciclo-Oxigenase 2/metabolismo , Progressão da Doença , Humanos , Inflamação/sangue , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ácidos Neuramínicos/química , Fatores de Risco
13.
Langmuir ; 24(14): 7559-64, 2008 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-18563922

RESUMO

Dynamic acrylamide/acrylate polymeric brushes were synthesized at gold-plated quartz crystal surfaces. The crystals were initially coated with polystyrene-type thin films, derivatized with photolabile iniferter groups, and subsequently subjected to photoinitiated polymerization in acrylamide/acrylate monomer feeds. This surface-confined polymerization method enabled direct photocontrol over the polymerization, as followed by increased frequency responses of the crystal oscillations in a quartz crystal microbalance (QCM). The produced polymer layers were also found to be highly sensitive to external acid/base stimuli. Large oscillation frequency shifts were detected when the brushes were exposed to buffer solutions of different pH. The dynamic behavior of the resulting polymeric brushes was evaluated, and the extent of expansion and contraction of the films was monitored by the QCM setup in situ in real time. The resulting responses were rapid, and the effects were fully reversible. Low pH resulted in full contractions of the films, whereas higher pH yielded maximal expansion in order to minimize repulsion around the charged acrylate centers. The surfaces also proved to be very robust because the responsiveness was reproducible over many cycles of repeated expansion and contraction. Using ellipsometry, copolymer layers were estimated to be approximately 220 nm in a collapsed state and approximately 340 nm in the expanded state, effectively increasing the thickness of the film by 55%.

14.
Cancer Res ; 68(2): 388-94, 2008 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-18199532

RESUMO

Sialic acids on vertebrate cell surfaces mediate many biological roles. Altered expression of certain sialic acid types or their linkages can have prognostic significance in human cancer. A classic but unexplained example is enhanced alpha2-6-sialylation on N-glycans resulting from overexpression of the Golgi enzyme beta-galactoside:alpha2-6-sialyltransferase (ST6Gal-I). Previous data supporting a role for the resulting Sia alpha 2-3Gal beta 1-4GlcNAc (Sia6LacNAc) structure in tumor biology were based on in vitro studies in transfected carcinoma cells, in which increased Sia6LacNAc on beta1-integrins enhanced their binding to ligands, and stimulated cell motility. Here, we examine for the first time the in vivo role of the ST6Gal-I enzyme in the growth and differentiation of spontaneous mammary cancers in mice transgenic for a mouse mammary tumor virus promoter-driven polyomavirus middle T antigen, a tumor in which beta1-integrin function is important for tumorigenesis and in maintaining the proliferative state of tumor cells. Tumors induced in St6gal1-null animals were more differentiated compared with those in the wild-type background, both by histologic analysis and by protein expression profiles. Furthermore, we show the St6gal1-null tumors have selectively altered expression of genes associated with focal adhesion signaling and have decreased phosphorylation of focal adhesion kinase, a downstream target of beta1-integrins. This first in vivo evidence for a role of ST6Gal-I in tumor progression was confirmed using a novel approach, which conditionally restored St6gal1 in cell lines derived from the null tumors. These findings indicate a role for ST6Gal-I as a mediator of tumor progression, with its expression causing a less differentiated phenotype, via enhanced beta1-integrin function.


Assuntos
Carcinoma/patologia , Neoplasias Mamárias Experimentais/patologia , Polissacarídeos/química , Ácidos Siálicos/fisiologia , Sialiltransferases/fisiologia , Animais , Carcinoma/enzimologia , Carcinoma/genética , Diferenciação Celular , Progressão da Doença , Feminino , Quinase 1 de Adesão Focal/metabolismo , Regulação Enzimológica da Expressão Gênica , Integrina beta1/metabolismo , Neoplasias Mamárias Experimentais/enzimologia , Neoplasias Mamárias Experimentais/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Biológicos , Polissacarídeos/metabolismo , Polissacarídeos/fisiologia , Ácidos Siálicos/química , Ácidos Siálicos/metabolismo , Sialiltransferases/genética , Sialiltransferases/metabolismo , Transdução de Sinais/genética , Células Tumorais Cultivadas , beta-D-Galactosídeo alfa 2-6-Sialiltransferase
15.
J Am Chem Soc ; 130(1): 26-7, 2008 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-18076179

RESUMO

The dinuclear RuII-PdII complex shows efficient H2 production in the presence of triethylamine as a sacrificial electron and proton donor under visible light irradiation. XPS and TEM analyses reveal that photoreduction of PdII to Pd0 causes dissociation of Pd from the complex to form colloids that are suggested to be the actual catalyst for H2 production.

16.
Mol Cell Biol ; 27(12): 4340-6, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17420276

RESUMO

Humans and chimpanzees share >99% identity in most proteins. One rare difference is a human-specific inactivating deletion in the CMAH gene, which determines biosynthesis of the sialic acid N-glycolylneuraminic acid (Neu5Gc). Since Neu5Gc is prominent on most chimpanzee cell surfaces, this mutation could have affected multiple systems. However, Neu5Gc is found in human cancers and fetuses and in trace amounts in normal human tissues, suggesting an alternate biosynthetic pathway. We inactivated the mouse Cmah gene and studied the in vivo consequences. There was no evidence for an alternate pathway in normal, fetal, or malignant tissue. Rather, null fetuses accumulated Neu5Gc from heterozygous mothers and dietary Neu5Gc was incorporated into oncogene-induced tumors. As with humans, there were accumulation of the precursor N-acetylneuraminic acid and increases in sialic acid O acetylation. Null mice showed other abnormalities reminiscent of the human condition. Adult mice showed a diminished acoustic startle response and required higher acoustic stimuli to increase responses above the baseline level. In this regard, histological abnormalities of the inner ear occurred in older mice, which had impaired hearing. Adult animals also showed delayed skin wound healing. Loss of Neu5Gc in hominid ancestors approximately 2 to 3 million years ago likely had immediate and long-term consequences for human biology.


Assuntos
Biologia , Evolução Molecular , Ácidos Neuramínicos/metabolismo , Acetilação , Estimulação Acústica , Animais , Cromatografia Líquida de Alta Pressão , Estudos de Coortes , DNA/genética , Orelha Interna/anormalidades , Feminino , Deleção de Genes , Heterozigoto , Hominidae/genética , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Fenilenodiaminas/farmacologia , Reação em Cadeia da Polimerase , Reflexo de Sobressalto/genética , Pele/lesões , Fatores de Tempo , Cicatrização/fisiologia
17.
Matrix Biol ; 21(4): 325-35, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12128070

RESUMO

To gain further insight into the synthesis and structure of the synovial matrix of joints, we have established cell cultures from synovial specimens and elaborated their production of hyaluronan and proteoglycans. The cultures secreted mainly the small proteoglycan decorin, but also considerable amounts of the related biglycan and the large proteoglycan versican. Only minor amounts of heparan sulfate proteoglycans were found. All cultures also had a high production of hyaluronan, which highlights the important role for normal joint function of these cells. In joint diseases, a common feature is the presence of an extra chromosome 7 (trisomy 7) in the synovial cells. To study the possible consequences of trisomy 7 on the synovial cell function, we extended our study to cultures that had been sub-cloned to contain high amounts of trisomy 7-carrying cells. These cell cultures had approximately four times more versican than their disomic counterparts in the cell culture medium, indicating that versican may be a mediator in the processes of joint destructive disorders. To find an explanation for this increase in versican, we investigated the expression/secretion of PDGF-AA and IL-6, cytokines with their genes located to chromosome 7. Indeed, both these cytokines were increased in the cultures with high frequencies of trisomy 7. We then added the two cytokines to cell cultures of disomic synovial cells, but only cells treated with IL-6 displayed an increased amount of versican. Thus, we suggest that the increased amount of versican in cultures of trisomy 7-carrying cells relates to an autocrine loop involving an increased IL-6 production.


Assuntos
Cromossomos Humanos Par 7/genética , Proteoglicanas/biossíntese , Membrana Sinovial/citologia , Membrana Sinovial/metabolismo , Trissomia/genética , Células Cultivadas , Proteoglicanas de Sulfatos de Condroitina/biossíntese , Proteoglicanas de Sulfatos de Condroitina/metabolismo , Humanos , Ácido Hialurônico/biossíntese , Hibridização in Situ Fluorescente , Interleucina-6/metabolismo , Lectinas Tipo C , Fator de Crescimento Derivado de Plaquetas/biossíntese , Fator de Crescimento Derivado de Plaquetas/genética , Fator de Crescimento Derivado de Plaquetas/metabolismo , Proteoglicanas/metabolismo , Líquido Sinovial/metabolismo , Fator de Crescimento Transformador beta/biossíntese , Fator de Crescimento Transformador beta/genética , Versicanas
18.
Glycoconj J ; 19(7-9): 433-40, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-14758066

RESUMO

Good evidence suggest roles of galectins in cancer, immunity and inflammation, and development, but a unifying picture of their biological function is lacking. Instead galectins appear to have a particularly diverse, bewildering but intriguing array of activities both inside and outside cells--"clear truths and mysteries are inextricably twined". Fortunately this has not discouraged but rather enthused a large number of good galectin researchers, some of which have contributed to this special issue of Glycoconjugate Journal to provide a personal, critical status of the field. Here we will give a brief introduction to the galectins as a protein family with some comments on nomenclature.


Assuntos
Galectinas/química , Galectinas/metabolismo , Animais , Evolução Molecular , Galectinas/classificação , Humanos , Estrutura Terciária de Proteína
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...