RESUMO
AIMS: The purpose of this study was to identify the number of pregnancies affected by pre-gestational diabetes in the Republic of Ireland; to report on pregnancy outcomes and to identify areas for improvement in care delivery and clinical outcomes. METHODS: Healthcare professionals caring for women with pre-gestational diabetes during pregnancy were invited to participate in this retrospective study. Data pertaining to 185 pregnancies in women attending 15 antenatal centres nationally were collected and analysed. Included pregnancies had an estimated date of delivery between 1 January and 31 December 2015. RESULTS: The cohort consisted of 122 (65.9%) women with Type 1 diabetes and 56 (30.3%) women with Type 2 diabetes. The remaining 7 (3.8%) pregnancies were to women with maturity-onset diabetes of the young (MODY) (n = 6) and post-transplant diabetes (n = 1). Overall women were poorly prepared for pregnancy and lapses in specific areas of service delivery including pre-pregnancy care and retinal screening were identified. The majority of pregnancies 156 (84.3%) resulted in a live birth. A total of 103 (65.5%) women had a caesarean delivery and 58 (36.9%) infants were large for gestational age. CONCLUSIONS: This audit identifies clear areas for improvement in delivery of care for women with diabetes in the Republic of Ireland before and during pregnancy.
Assuntos
Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 2/terapia , Cuidado Pré-Concepcional/estatística & dados numéricos , Resultado da Gravidez/epidemiologia , Gravidez em Diabéticas/terapia , Aborto Espontâneo/epidemiologia , Adulto , Aspirina/uso terapêutico , Cesárea , Auditoria Clínica , Atenção à Saúde , Parto Obstétrico , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Retinopatia Diabética/diagnóstico , Feminino , Macrossomia Fetal/epidemiologia , Ácido Fólico/uso terapêutico , Hemoglobinas Glicadas/metabolismo , Humanos , Hipoglicemiantes/uso terapêutico , Recém-Nascido , Bombas de Infusão Implantáveis , Insulina/uso terapêutico , Sistemas de Infusão de Insulina , Unidades de Terapia Intensiva Neonatal/estatística & dados numéricos , Irlanda/epidemiologia , Nascido Vivo/epidemiologia , Programas de Rastreamento , Metformina/uso terapêutico , Inibidores da Agregação Plaquetária/uso terapêutico , Gravidez , Nascimento Prematuro/epidemiologia , Estudos Retrospectivos , Natimorto/epidemiologia , Complexo Vitamínico B/uso terapêuticoRESUMO
Proteus mirabilis forms extensive crystalline biofilms on urethral catheters that occlude urine flow and frequently complicate the management of long-term-catheterized patients. Here, using random transposon mutagenesis in conjunction with in vitro models of the catheterized urinary tract, we elucidate the mechanisms underpinning the formation of crystalline biofilms by P. mirabilis. Mutants identified as defective in blockage of urethral catheters had disruptions in genes involved in nitrogen metabolism and efflux systems but were unaffected in general growth, survival in bladder model systems, or the ability to elevate urinary pH. Imaging of biofilms directly on catheter surfaces, along with quantification of levels of encrustation and biomass, confirmed that the mutants were attenuated specifically in the ability to form crystalline biofilms compared with that of the wild type. However, the biofilm-deficient phenotype of these mutants was not due to deficiencies in attachment to catheter biomaterials, and defects in later stages of biofilm development were indicated. For one blocking-deficient mutant, the disrupted gene (encoding a putative multidrug efflux pump) was also found to be associated with susceptibility to fosfomycin, and loss of this system or general inhibition of efflux pumps increased sensitivity to this antibiotic. Furthermore, homologues of this system were found to be widely distributed among other common pathogens of the catheterized urinary tract. Overall, our findings provide fundamental new insight into crystalline biofilm formation by P. mirabilis, including the link between biofilm formation and antibiotic resistance in this organism, and indicate a potential role for efflux pump inhibitors in the treatment or prevention of P. mirabilis crystalline biofilms.
Assuntos
Biofilmes/crescimento & desenvolvimento , Cateteres de Demora/microbiologia , Proteus mirabilis/fisiologia , Análise de Variância , Antibacterianos/farmacologia , Cálcio/análise , Movimento Celular , Elementos de DNA Transponíveis/fisiologia , Perfilação da Expressão Gênica , Humanos , Testes de Sensibilidade Microbiana , Microscopia Eletroquímica de Varredura , Microscopia Eletrônica de Varredura , Dados de Sequência Molecular , Mutagênese , Proteus mirabilis/efeitos dos fármacos , Proteus mirabilis/genética , Análise de Sequência de DNA , Urease/metabolismo , Cateterismo Urinário/instrumentaçãoRESUMO
AIMS: Pre-gestational diabetes mellitus (PGDM) is associated with adverse outcomes. We aimed to examine pregnancies affected by PGDM; report on these pregnancy outcomes and compare outcomes for patients with type 1 versus type 2 diabetes mellitus; compare our findings to published Irish and United Kingdom (UK) data and identify potential areas for improvement. METHODS: Between 2016 and 2018 information on 679 pregnancies from 415 women with type 1 Diabetes Mellitus and 244 women with type 2 diabetes was analysed. Data was collected on maternal characteristics; pregnancy preparation; glycaemic control; pregnancy related complications; foetal and maternal outcomes; unscheduled hospitalisations; congenital anomalies and perinatal deaths. RESULTS: Only 15.9% of women were adequately prepared for pregnancy. Significant deficits were identified in availability and attendance at pre-pregnancy clinic, use of folic acid, attaining appropriate glycaemic targets and appropriate retinal screening. The majority of pregnancies (n = 567, 83.5%) resulted in a live birth but the large number of infants born large for gestational age (LGA) (n = 280, 49.4%), born prematurely <37 weeks and requiring neonatal intensive care unit (NICU) admission continue to be significant issues. CONCLUSIONS: This retrospective cohort study identifies multiple targets for improvements in the provision of care to women with pre-gestational DM which are likely to translate into better pregnancy outcomes.
Assuntos
Resultado da Gravidez , Gravidez em Diabéticas/diagnóstico , Gravidez em Diabéticas/epidemiologia , Adulto , Estudos de Coortes , Feminino , Humanos , Irlanda , Gravidez , Estudos RetrospectivosRESUMO
The ability of Legionella pneumophila to colonise domestic water systems is a primary cause of outbreaks of Legionnaire's disease in humans. World Health Organization guidelines recommend that drinking water is chlorinated to between 0.2 and 1mg/L [Chlorine in drinking-water. Guidelines for drinking-water quality, 2nd edn. Geneva: World Health Organization; 1996], but L. pneumophila is repeatedly isolated from chlorinated water systems, indicating that this treatment is not effective at preventing colonisation. Current UK guidelines recommend a one-off treatment of 20-50mg/L of free chlorine to remove the bacteria. In this study we report on the persistence of L. pneumophila serogroup 1 in a domestic shower system despite repeated cycles of chlorination at 50mg/L for 1h exposure time, over the course of two and a half years. Persisting isolates were subjected to in-vitro phenotypic analyses and polymerase chain reaction analysis for the toxin-encoding mip gene. Random amplified polymorphic DNA typing was also performed to determine whether the isolates recovered on different occasions were the same strain. We found that seven isolates of L. pneumophila recovered over a two-and-a-half year period are the same genetically defined strain, indicating that the bacteria can persist despite repeated cycles of chlorination after each successive isolation.
Assuntos
Proteínas de Bactérias/genética , Cloro/farmacologia , Legionella pneumophila/crescimento & desenvolvimento , Legionella pneumophila/isolamento & purificação , Peptidilprolil Isomerase/genética , Microbiologia da Água , Abastecimento de Água , Cidades , Impressões Digitais de DNA/métodos , Desinfecção/métodos , Eletroforese em Gel de Ágar , Humanos , Legionella pneumophila/efeitos dos fármacos , Legionella pneumophila/genética , Reação em Cadeia da Polimerase , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
IgM paraproteins associated with autoimmune peripheral neuropathy and anti-Pr cold agglutinins react with sialic acid epitopes present on disialylated gangliosides including GD1b, GT1b, GQ1b, and GD3. A causal relationship between the paraprotein and the neuropathy has never been proven experimentally. From peripheral blood B cells of an affected patient, we have cloned a human hybridoma secreting an antidisialosyl IgM mAb, termed Ha1, that shows identical structural and functional characteristics to its serum counterpart. Variable region analysis shows Ha1 is encoded by the same VH1 family heavy chain gene, V1-18, as the only other known anti-Pr antibody sequence and is somatically mutated, suggesting that it [correction of is] arose in vivo in response to antigenic stimulation. In the rodent peripheral nervous system, Ha1 immunolocalizes to dorsal root ganglia, motor nerve terminals, muscle spindles, myelinated axons, and nodes of Ranvier. After intraperitoneal injection of affinity-purified antibody into mice for 10 d, electrophysiological recordings from the phrenic nerve-hemidiaphragm preparation demonstrated impairment of nerve excitability and a reduction in quantal release of neurotransmitter. These data unequivocally establish that an antidisialosyl antibody can exert pathophysiological effects on the peripheral nervous system and strongly support the view that the antibody contributes to the associated human disease.
Assuntos
Autoanticorpos/genética , Gangliosídeos/imunologia , Genes de Imunoglobulinas , Cadeias Pesadas de Imunoglobulinas/genética , Imunoglobulina M/genética , Região Variável de Imunoglobulina/genética , Doenças do Sistema Nervoso Periférico/etiologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Autoanticorpos/imunologia , Sequência de Bases , Sequência de Carboidratos , Humanos , Imunoglobulina M/imunologia , Camundongos , Dados de Sequência Molecular , Mutação , Doenças do Sistema Nervoso Periférico/patologia , Doenças do Sistema Nervoso Periférico/fisiopatologiaRESUMO
Guillain-Barré syndrome and its variant, Miller-Fisher syndrome, are acute, postinfectious, autoimmune neuropathies that frequently follow Campylobacter jejuni enteritis. The pathogenesis is believed to involve molecular mimicry between sialylated epitopes on C. jejuni LPSs and neural gangliosides. More than 90% of Miller-Fisher syndrome cases have serum anti-GQ1b and anti-GT1a ganglioside antibodies that may also react with other disialylated gangliosides including GD3 and GD1b. Structural studies on LPS from neuropathy-associated C. jejuni strains have revealed GT1a-like and GD3-like core oligosaccharides. To determine whether this structural mimicry results in pathogenic autoantibodies, we immunized mice with GT1a/GD3-like C. jejuni LPS and then cloned mAb's that reacted with both the immunizing LPS and GQ1b/GT1a/GD3 gangliosides. Immunohistology demonstrated antibody binding to ganglioside-rich sites including motor nerve terminals. In ex vivo electrophysiological studies of nerve terminal function, application of antibodies either ex vivo or in vivo via passive immunization induced massive quantal release of acetylcholine, followed by neurotransmission block. This effect was complement-dependent and associated with extensive deposits of IgM and C3c at nerve terminals. These data provide strong support for the molecular mimicry hypothesis as a mechanism for the induction of cross-reactive pathogenic anti-ganglioside/LPS antibodies in postinfectious neuropathies.
Assuntos
Anticorpos Monoclonais/imunologia , Campylobacter jejuni/imunologia , Gangliosídeos/imunologia , Lipopolissacarídeos/imunologia , Junção Neuromuscular/fisiologia , Polirradiculoneuropatia/microbiologia , Animais , Complemento C3/fisiologia , Reações Cruzadas , Feminino , Imunização , Imunoglobulina M/imunologia , Masculino , Camundongos , Camundongos Endogâmicos , Nervos Periféricos/imunologiaRESUMO
Recent focus on national standards within Australian hospitals has prompted a focus on the training of our staff in advanced life support (ALS). Research in critical care nursing has questioned the traditional annual certification of ALS competence as the best method of delivering this training. Simulation and team-based training may provide better ALS education to intensive care unit (ICU) staff. Our new inter-professional team-based advanced life support program involved ICU staff in a large private metropolitan ICU. A prospective observational study using three standardised questionnaires and two multiple choice questionnaire assessments was conducted. Ninety-nine staff demonstrated a 17.8% (95% confidence interval 4.2-31, P=0.01) increase in overall ICU nursing attendance at training sessions. Questionnaire response rates were 93 (94%), 99 (100%) and 60 (61%) respectively; 51 (52%) staff returned all three. Criteria were assessed by scores from 0 to 10. Nurses reported improved satisfaction with the education program (9.4 to 7.1, P <0.001), as well as improvement in role understanding (8.7 and 9.1 versus 7.9 and 8.2, P <0.001) and confidence (8.4 and 8.8 versus 7.4 and 7.8, P <0.001) during ALS provision (outside ICU and inside ICU) following the course when compared to before the program. Doctors' only statistically significant improvement was in their confidence in ALS provision outside ICU (8.7 versus 8.1, P=0.04). The new program cost approximately an extra $16,500 in nursing salaries. We concluded that team-based, inter-professional ALS training produced statistically significant improvements in nursing attendance, satisfaction with ALS education, confidence and role understanding compared to traditional ALS training.
Assuntos
Suporte Vital Cardíaco Avançado/educação , Competência Clínica , Capacitação em Serviço/organização & administração , Unidades de Terapia Intensiva , Adulto , Suporte Vital Cardíaco Avançado/normas , Austrália , Cuidados Críticos/normas , Humanos , Corpo Clínico Hospitalar/educação , Corpo Clínico Hospitalar/psicologia , Corpo Clínico Hospitalar/normas , Pessoa de Meia-Idade , Recursos Humanos de Enfermagem Hospitalar/educação , Recursos Humanos de Enfermagem Hospitalar/psicologia , Recursos Humanos de Enfermagem Hospitalar/normas , Equipe de Assistência ao Paciente/organização & administração , Papel Profissional , Estudos Prospectivos , Treinamento por Simulação/métodos , Inquéritos e QuestionáriosRESUMO
The minimum inhibitory concentration (MIC) of a homologous series of alcohol ethoxylates with the same head group size (E6) but differing in the number of carbon atoms in their 'tail group' from 10 to 16 was determined for Staphylococcus aureus NCTC 4163 and Escherichia coli NCTC 8196 using a turbidimetric assay. All the surfactants tested demonstrated bacteriostatic activity against both organisms. A tetrazolium assay showed that C14E6 and C16E6 had little effect on the membrane-bound dehydrogenase enzyme activity of E. coli NCTC 8196 compared with C10E6 and C12E6. C10E6 caused leakage both of K(+) and nucleotides in a concentration-dependent manner above its MIC of 0.2 mM. C12E6 caused some leakage at concentrations below its MIC (0.12 mM).
Assuntos
Álcoois/farmacologia , Antibacterianos/farmacologia , Membrana Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Tensoativos/farmacologia , Permeabilidade da Membrana Celular/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Staphylococcus aureus/efeitos dos fármacosRESUMO
We have recently cloned a panel os monoclonal IgM anti-GM1 ganglioside antibodies from peripheral blood lymphocytes of patients with multifocal motor neuropathy and Guillain Barré syndrome. In solid-phase immunoassay, the antibodies all reacted with GM1 and also reacted to different degrees with the structurally related glycolipids asialo-GM1 and GD1b. These antibodies are being used to study the pathogenesis of the anti-GM1 antibody-medicated neuropathy in different experimental systems. In the present immunofluorescence study we report the binding patterns of 5 of these antibodies in the rodent nervous system. The antibodies demonstrated highly diverse binding patterns on tissue sections and teased fibers when compared to one another and between species. The antibodies bound many central and peripheral nervous system structures, including neurons and myelin, motor end plate regions, and muscle spindles. The diversity of binding shown by these antibodies provide evidence that may account for the differing clinical phenotypes, including normality, associated with elevated titers of anti-GM1 antibodies.
Assuntos
Gangliosídeo G(M1)/imunologia , Doença dos Neurônios Motores/metabolismo , Sistema Nervoso/metabolismo , Animais , Proposta de Concorrência , Humanos , Imuno-Histoquímica , Camundongos , Microscopia Confocal , Doença dos Neurônios Motores/imunologia , Sistema Nervoso/imunologia , Ratos , Ratos Sprague-DawleyRESUMO
When injected with [3H]ecdysone and maintained in vitro, the parasitic nematodes, Ascaris suum and Parascaris equorum each produced a series of polar and relatively apolar metabolites. A. suum metabolised the compound into ecdysonoic acid ([3H]EOIC), ecdysone 25-glucoside ([3H]E25gluc), putative ecdysone 22-phosphate ([3H]E22P) and a series of at least six relatively apolar metabolites. All of these, except ecdysonoic acid, were hydrolysed by a crude enzyme preparation from Helix pomatia, releasing ecdysone. In a similar study, P. equorum produced ecdysone 25-glucoside, putative ecdysone 22-phosphate and a series of relatively apolar compounds all of which were hydrolysed by H. pomatia enzymes, releasing ecdysone. [3H]Ecdysone 25-glucoside was the most abundant single metabolite in both species, and in P. equorum, at least, was released into the culture medium in relatively large amounts. Apolar metabolites were present in worm samples and were the major, if not the only radiolabelled compounds detected in eggs of both species. Data indicated a metabolic relationship between some of the apolar conjugates found in both nematode species and ecdysone 25-glucoside.
Assuntos
Ascaris/metabolismo , Hormônios de Invertebrado/metabolismo , Nematoides/metabolismo , Animais , Ecdisteroides , Feminino , Glicoconjugados/metabolismo , Masculino , Especificidade da EspécieRESUMO
Over the past decade, remarkable progress has been made in our understanding of the pathogenesis of Miller Fisher syndrome (MFS), a clinical variant of Guillain Barré syndrome (GBS). MFS comprises the clinical triad of ataxia, areflexia and ophthalmoplegia. It is associated with acute-phase IgG antibodies to GQ1b and GT1a gangliosides in over 90% of cases which are highly disease specific. Like GBS, MFS is a post-infectious syndrome following diverse infections, but particular attention has been paid to its association with Campylobacter jejuni enteritis. Serostrains of C. jejuni isolated from infected patients bear ganglioside-like epitopes in their lipopolysaccharide core oligosaccharides, which elicit humoral immune responses exhibiting molecular mimicry with GQ1b/GT1a gangliosides. These antibodies are believed to be the principal cause of the syndrome and physiological studies aimed at proving this have focused on the motor-nerve terminal as a potential site of pathogenic action. This review describes these findings and formulates a pathogenesis model based on our current state of knowledge.
Assuntos
Síndrome de Miller Fisher/imunologia , Animais , Doenças Autoimunes/sangue , Cromatografia em Camada Fina , Gangliosídeos/imunologia , Humanos , Infecções/complicações , Síndrome de Miller Fisher/sangue , Oligossacarídeos/imunologia , Nervos Periféricos/imunologia , Fenótipo , RatosRESUMO
IgM paraproteins from patients with CANOMAD (chronic ataxic neuropathy, ophthalmoplegia, M-protein, agglutination, anti-disialosyl antibodies) react with NeuAc(alpha 2-8)NeuAc epitopes on a wide range of gangliosides including GQ1b, GT1a, GD1b and GD3. The tissue distribution of reactive antigens in human peripheral nerve has not been addressed in detail. In addition, the origin of these antibodies is unknown. Here we report that purified anti-disialosyl paraproteins from two affected patients bind a wide array of human peripheral nerve structures including dorsal root ganglia, dorsal and ventral root axons, femoral and oculomotor nerves. We also show that these paraproteins bind lipopolysaccharides of Campylobacter jejuni isolates from 3/3 cases of Miller Fisher syndrome, and to a less frequent extent, from cases of Guillain-Barré syndrome and enteritis controls. In conjunction with our previous studies, these data provide a possible causal link between the origin and pathogenic effects of anti-disialosyl antibodies in human paraproteinaemic neuropathy.
Assuntos
Campylobacter jejuni/metabolismo , Imunoglobulina M/metabolismo , Lipopolissacarídeos/metabolismo , Proteínas Musculares , Paraproteínas/metabolismo , Nervos Periféricos/metabolismo , Ácidos Siálicos/metabolismo , Aglutinação , Ataxia/imunologia , Ataxia/metabolismo , Doença Crônica , Conectina , Eritrócitos/imunologia , Eritrócitos/metabolismo , Técnica Direta de Fluorescência para Anticorpo , Gangliosídeos/imunologia , Humanos , Imunoglobulina M/biossíntese , Imunoglobulina M/sangue , Masculino , Microscopia de Fluorescência , Pessoa de Meia-Idade , Proteínas do Mieloma/análise , Oftalmoplegia/imunologia , Oftalmoplegia/metabolismoRESUMO
Motoneurons supplying the extensor hallucis longus muscle of the rat were temporarily separated from the muscle by sciatic nerve-crush at five days postnatally. Such treatment permanently alters the reflex response of the affected motoneurons without the large-scale cell death associated with nerve-crush at birth. After reinnervation, the motoneurons were retrogradely labelled with cholera toxin subunit-B conjugated to horseradish peroxidase and the dendritic tree of each labelled cell was analysed. When compared to normal data, significantly higher levels of dendritic density were observed in the rostrodorsally orientated parts of the dendritic field. This was similar to that found previously for the same motor pool after nerve-crush at birth. However, in other parts of the field where a lower dendritic density was found after nerve-crush at birth, no change was seen after nerve-crush at five days. These data present evidence for the influence of sensory afferents on the development of motoneuron dendrites. Taken together with the previous findings after nerve-crush at birth, we suggest that the differential dendritic changes caused by neonatal nerve lesion contribute to an imbalance in the pattern of excitatory and inhibitory inputs to the motoneuron, which results either in cell death, or the abnormal activity seen in those motoneurons which survive.
Assuntos
Envelhecimento/fisiologia , Animais Recém-Nascidos/fisiologia , Dendritos/ultraestrutura , Neurônios Motores/ultraestrutura , Compressão Nervosa , Nervo Isquiático/fisiologia , Animais , Toxina da Cólera , Peroxidase do Rábano Silvestre , Músculos/inervação , Ratos , Ratos Wistar , Dedos do PéRESUMO
Disruption of neuromuscular contact by nerve-crush during the early postnatal period results in the death of a large proportion of affected motoneurons. Increased activity and abnormal reflex responses are evident in those that survive. We have studied the aberrant dendritic morphology of surviving cells and have attempted to correlate the observed alterations in morphology with the above experimental findings. Motoneurons supplying the extensor hallucis longus muscles of the rat were retrogradely labelled with cholera toxin subunit-B conjugated to horseradish peroxidase. The dendritic tree of labelled cells was analysed in adult animals having undergone unilateral sciatic nerve-crush at birth. Unoperated control animals were also examined. Following nerve-crush at birth, total visible dendritic length was more than 30% smaller than control cells in the transverse plane. This decrease was confined largely to the medially directed segments of the dendritic field and appeared to be due to a reduction in dendritic branching combined with a failure to achieve the correct branch length. There was no overall change in total visible dendritic length in the longitudinal plane, but a reorientation of dendrites in favour of rostrodorsal regions was observed. There was no alteration in dendritic length in cells contralateral to the nerve injury. These results show that nerve injury during early postnatal development produces lasting changes in the distribution of motoneuron dendrites. The localized nature of these changes may explain the altered activity and induced death of motoneurons seen after neonatal nerve-crush.
Assuntos
Animais Recém-Nascidos/fisiologia , Dendritos/ultraestrutura , Neurônios Motores/ultraestrutura , Nervo Isquiático/lesões , Animais , Tamanho Celular , Dendritos/fisiologia , Neurônios Motores/fisiologia , Compressão Nervosa , Ratos , Ratos Wistar , Nervo Isquiático/ultraestruturaRESUMO
1. Evidence is accumulating for multiple sigma (sigma) sites in the mammalian CNS. 2. We have addressed this problem and have examined sigma site - G-protein coupling in guinea-pig and rat brain membranes. 3. Ditolylorthoguanidine (DTG), (+)-3-(3-hydroxyphenyl)-N-1-(propyl)piperidine (3PPP) and dextromethorphan displaced [3H]-DTG (3.4 nM) with low Hill slopes of 0.5, 0.6 and 0.6, respectively in guinea-pig brain membranes. 4. In the presence of 5'-guanylylimidodiphosphate (Gpp(NH)p; 100 microM), the specific binding of [3H]-DTG was reduced by 36.7%, the Hill slope of 3PPP was increased to near unity, the ability of dextromethorphan to displace DTG was virtually abolished and the Hill slope for DTG remained low (0.7), indicating the presence of at least two binding sites. These data indicate that although Gpp(NH)p removes a dextromethorphan high affinity site, two DTG selective sites remain in the presence of Gpp(NH)p. 5. The present study suggests that DTG binds to at least three sites in guinea-pig brain membranes, at least one of which is G-protein linked. 6. In rat brain membranes, DTG displaced itself (3.4 nM) with a Hill slope near 1. 3PPP displacement of [3H]-DTG was comparable with the guinea-pig (Hill slope 0.5) and displaced from more than 1 site. Dextromethorphan did not displace [3H]-DTG at concentrations below 10 microM. 7. The heterogeneity of sigma sites appears to be less in rat than in guinea-pig brain membranes.
Assuntos
Química Encefálica/fisiologia , Proteínas de Ligação ao GTP/metabolismo , Receptores Opioides delta/metabolismo , Animais , Ligação Competitiva/efeitos dos fármacos , Dextrometorfano/farmacologia , Dopaminérgicos/farmacologia , Guanidinas/farmacologia , Cobaias , Técnicas In Vitro , Masculino , Membranas/efeitos dos fármacos , Membranas/metabolismo , Piperidinas/farmacologia , Ensaio Radioligante , Ratos , Ratos WistarRESUMO
GM2 ganglioside is a potential peripheral nerve antigen for neuropathy-associated autoantibodies. However little data are available on their pathogenic effects, if any. In this study we have screened both neuropathy-associated and control sera for anti-GM2 antibodies and subsequently used high titre sera for immunohistological and complement mediated cytotoxicity studies. We identified abnormally elevated anti-GM2 antisera in the normal population, as well as in patients with peripheral neuropathies and other neurological diseases. GM2 antibodies were either mono-reactive, cross-reactive with GM1a, or cross-reactive with GalNAc-GM1b and/or GalNAc-GD1a. All GM2 antisera from neuropathy subjects and normal controls bound to, and were capable of complement-mediated lysis of the NSC-34 cell line which expresses high levels of membrane-associated GM2. However, in immunohistological studies on human and rodent peripheral nervous system tissues, no specific binding was seen with GM2 antisera, either cross-reactive with GalNAc-GM1b and GalNAc-GDla, or with GM1a. These data indicate that although GM2 antisera can lyse neural membranes containing GM2, this antigen(s) is not detectable by standard immunohistological techniques in human or rodent peripheral nerve. This raises doubts about their pathophysiological significance in human autoimmune neuropathy.
Assuntos
Autoanticorpos/sangue , Gangliosídeo G(M2)/imunologia , Doenças do Sistema Nervoso Periférico/imunologia , Adolescente , Adulto , Esclerose Lateral Amiotrófica/imunologia , Esclerose Lateral Amiotrófica/patologia , Estudos de Casos e Controles , Linhagem Celular , Reações Cruzadas , Citotoxicidade Imunológica , Síndrome de Guillain-Barré/imunologia , Síndrome de Guillain-Barré/patologia , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Doença dos Neurônios Motores/imunologia , Doença dos Neurônios Motores/patologia , Doenças do Sistema Nervoso Periférico/patologiaRESUMO
The aim of this study was to investigate in vitro adhesion of clinically relevant bacteria to standard HEMA and novel biomimetic soft contact lenses (SCL) using bioluminescent ATP assay and image analysis. Unworn SCL were incubated with Pseudomonas aeruginosa, Staphylococcus epidermidis or Serratia marcescens suspended in sterile phosphate buffered saline (PBS). The level of bacterial adhesion after 1, 2, 4, 6 and 18h, was assessed using both image analysis and a bioluminescent ATP assay. Species differences in the overall level of adhesion to the different types of lens were observed using both measurement techniques. Generally bacterial adhesion was shown to peak at 4-6 h, then decline to a much lower level by 18 h. After 4 h, adhesion of all species of bacteria to the biomimetic SCL (omafilcon A) was found to be significantly lower than to the standard HEMA SCL (polymacon) (p<0.05. Student's t-test, n = 4). Both these techniques demonstrated that novel biomimetic SCL materials exhibit significantly lower bacterial adhesion in vitro compared to standard HEMA SCL materials. SCL manufactured with these novel biomimetic materials may reduce the risk of infection.
Assuntos
Aderência Bacteriana , Materiais Biocompatíveis/efeitos adversos , Lentes de Contato Hidrofílicas/efeitos adversos , Trifosfato de Adenosina/metabolismo , Biofilmes/crescimento & desenvolvimento , Humanos , Processamento de Imagem Assistida por Computador , Técnicas In Vitro , Ceratite/etiologia , Ceratite/prevenção & controle , Medições Luminescentes , Teste de Materiais , Metacrilatos , Pseudomonas aeruginosa/patogenicidade , Pseudomonas aeruginosa/fisiologia , Serratia marcescens/patogenicidade , Serratia marcescens/fisiologia , Staphylococcus epidermidis/patogenicidade , Staphylococcus epidermidis/fisiologia , Propriedades de SuperfícieRESUMO
Phosphorylcholine (PC)-based polymers have been used in a variety of medical device applications to improve biocompatibility. The use of PC-based materials for biomaterials is associated with low protein adsorption, reduced complement activation, low inflammatory response and cell adhesion. For some medical device applications however, materials that support cell adhesion are also beneficial, allowing host interaction and encouraging full incorporation within the body. As previous studies have suggested that cell adhesion to materials is enhanced by the addition of charge, PC-based polymers have therefore been modified to incorporate various concentrations of cationic charge. In this study, the affect of cationic charge on a range of biological responses was investigated. In vitro assays have been used to assess the adsorption of protein onto the materials surface, the adhesion of mouse fibroblasts and rabbit corneal epithelial cells and the adhesion of human mononuclear cells and granulocytes. The results corroborate previous work showing that PC without charge significantly reduces protein adsorption, cell adhesion and inflammatory cell activation. The addition of cationic charge to PC polymers however, resulted in an increase in all of the above responses. This increase did not however, increase linearly with cationic monomer concentration. The differences in cell adhesion are discussed in terms of differences in protein adsorption, cytotoxicity and/or stability of the different cationic polymer coatings.
Assuntos
Proteínas Sanguíneas/química , Materiais Revestidos Biocompatíveis/química , Epitélio Corneano/citologia , Granulócitos/citologia , Ativação de Macrófagos/fisiologia , Macrófagos/citologia , Fosforilcolina/química , Células 3T3 , Adsorção , Animais , Cátions , Adesão Celular/fisiologia , Divisão Celular/fisiologia , Células Cultivadas , Epitélio Corneano/fisiologia , Granulócitos/fisiologia , Humanos , Macrófagos/fisiologia , Teste de Materiais , Camundongos , Ligação Proteica , Coelhos , Eletricidade EstáticaRESUMO
Phosphorylcholine (PC)-based polymers have been used in a variety of medical device applications to improve biocompatibility. Here, solutions containing poly(butyl methacrylate) (PBMA) and 2-methacryloyloxyethyl phosphorylcholine-co-lauryl methacrylate (MPC-co-LMA(2)) copolymer were spin-coated onto glass coverslips at various ratios ranging from 5:1 to 1:0 for each of the two components, respectively. The resulting blend coatings were shown to be phase-separated on the nanometre-scale by atomic force microscopy, the PC copolymer within the blend being preferentially expressed at the surface. The adsorption of two key blood proteins, fibrinogen and albumin were investigated using surface plasmon resonance as an indicator of biocompatibility. The adsorption of protein to a biomaterials' surface can then stimulate further biological responses. This study therefore, also investigates the materials ability to elicit an inflammatory response by studying the adhesion of human mononuclear cells to the material surface. The materials ability to support the adhesion and growth of other tissue cells was also evaluated, looking specifically at the adhesion and proliferation of rabbit corneal epithelial cells. Results suggest that the adsorption of proteins and the adhesion of both corneal epithelial cells and mononuclear cells are dependent on the composition of the PBMA:MPC-co-LMA(2) copolymer.
Assuntos
Fosforilcolina/química , Polímeros/química , Ácidos Polimetacrílicos/química , Adsorção , Animais , Materiais Biocompatíveis , Adesão Celular , Divisão Celular , Células Epiteliais/citologia , Humanos , Inflamação , Leucócitos Mononucleares/citologia , Microscopia de Força Atômica , Modelos Químicos , Ligação Proteica , CoelhosRESUMO
The present study examined the utility of the rat vas deferens preparation as a bioassay for sigma site ligands. sigma Ligands such as (+/-)-pentazocine, phencyclidine (PCP) and (+)-SK&F 10047 potentiated neurogenic twitch contractions. However, neither the order of potency nor the absolute potency of (+/-)-pentazocine and (+)-SK&F 10047 correlated with their affinity at central sigma sites. Furthermore, another potent sigma ligand, ditolyl-ortho guanidine (DTG) neither affected neurogenic twitch contractions nor inhibited twitch potentiation by PCP or (+)-SK&F 10047 at concentrations up to 30 mumol/l. These data indicate that the rat vas deferens is not a useful bioassay for the evaluation of sigma ligands. PCP, (+)-SK&F 10047 and (+/-)-pentazocine probably enhance neurogenic contractions in rat vas deferens primarily by inhibition of the neuronal uptake of noradrenaline.