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1.
Int J Ment Health Addict ; : 1-12, 2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35571574

RESUMO

The prevalence of problematic Internet use (PIU) and its associated negative outcomes among college students has been heavily researched in developed countries. However, despite the increased accessibility of the Internet and indicators which may suggest PIU in developing countries such as Jamaica, PIU in this context remains grossly understudied. This study surveyed 277 Jamaican university students and found evidence of PIU, with younger respondents (ages 18-23) at risk. The findings also indicate that the predictors of PIU in this sample are depressive symptomatology, avoidant-attachment, and low social connectedness (R 2 = .208, F[7, 269] = 10.112, p < .001). Findings from the current study highlight that problematic Internet use is of concern in this developing context and warrants further exploration.

2.
Clin Exp Immunol ; 181(3): 401-6, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25766640

RESUMO

We investigated changes in circulating T helper type 17 (Th17) cells following anti-tumour necrosis factor (TNF) in rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) patients. Peripheral blood mononuclear cells (PBMC) were isolated from 25 RA, 15 AS and eight PsA patients at baseline 4 and 12 weeks after treatment, and Th17 cell frequencies were analysed using interleukin (IL)-17 enzyme-linked immunospot (ELISPOT) and flow cytometry. A significant increase in IL-17-producing cells was observed by ELISPOT in RA and AS patients at 12 weeks. Flow cytometry confirmed significant increases in CD4(+) IL-17(+) cells at 12 weeks in RA and AS and 4 weeks in PsA patients. Anti-TNF treatment increases circulating Th17 cells in three different diseases.


Assuntos
Antirreumáticos/uso terapêutico , Artrite Psoriásica/tratamento farmacológico , Artrite Reumatoide/tratamento farmacológico , Espondilite Anquilosante/tratamento farmacológico , Células Th17/efeitos dos fármacos , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Adalimumab , Adulto , Idoso , Anticorpos Monoclonais Humanizados/uso terapêutico , Artrite Psoriásica/sangue , Artrite Reumatoide/sangue , Ensaio de Imunoadsorção Enzimática , Etanercepte , Feminino , Citometria de Fluxo , Humanos , Imunoglobulina G/uso terapêutico , Interleucina-17/sangue , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Receptores do Fator de Necrose Tumoral/uso terapêutico , Espondilite Anquilosante/sangue , Células Th17/metabolismo , Fatores de Tempo , Resultado do Tratamento
3.
Phys Med Biol ; 60(2): 689-708, 2015 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-25554968

RESUMO

Applying the thermoacoustic (TA) effect to diagnostic imaging was first proposed in the 1980s. The object under test is irradiated by high-power pulses of electromagnetic energy, which heat tissue and cause thermal expansion. Outgoing TA pressure pulses are detected by ultrasound transducers and reconstructed to provide images of the object. The TA contrast mechanism is strongly dependent upon the frequency of the irradiating electromagnetic pulse. When very high frequency (VHF) electromagnetic irradiation is utilized, TA signal production is driven by ionic content. Prostatic fluids contain high levels of ionic metabolites, including citrate, zinc, calcium, and magnesium. Healthy prostate glands produce more ionic metabolites than diseased glands. VHF pulses are therefore expected to generate stronger TA signal in healthy prostate glands than in diseased glands. A benchtop system for performing ex vivo TA computed tomography with VHF energy is described and images are presented. The system utilizes irradiation pulses of 700 ns duration exceeding 20 kW power. Reconstructions frequently visualize anatomic landmarks such as the urethra and verumontanum. TA reconstructions from three freshly excised human prostate glands with little, moderate, and severe cancerous involvement are compared with histology. TA signal strength is negatively correlated with percent cancerous involvement in this small sample size. For the 45 regions of interest analyzed, a reconstruction value of 0.4 mV provides 100% sensitivity but only 29% specificity. This sample size is far too small to draw sweeping conclusions, but the results warrant a larger volume study including comparison of TA images to the gold standard, histology.


Assuntos
Acústica , Meios de Contraste , Radiação Eletromagnética , Temperatura Alta , Processamento de Imagem Assistida por Computador/métodos , Neoplasias da Próstata/radioterapia , Temperatura Corporal , Simulação por Computador , Humanos , Aumento da Imagem , Masculino , Neoplasias da Próstata/patologia , Razão Sinal-Ruído
4.
Diabetes Obes Metab ; 16(7): 651-60, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24962805

RESUMO

BACKGROUND: Systemic insulin resistance (IR) is a primary feature in non-alcoholic steatohepatitis (NASH), however, there remain limited data on tissue-specific insulin sensitivity in vivo. METHODS: We examined tissue-specific (adipose, muscle and liver) insulin sensitivity and inflammation in 16 European Caucasian patients with biopsy-confirmed NASH and in 15 healthy controls. All underwent a two-step hyperinsulinaemic euglycaemic clamp incorporating stable isotope measurements of carbohydrate and lipid metabolism with concomitant subcutaneous adipose tissue (SAT) microdialysis. RESULTS: Hepatic and muscle insulin sensitivity were decreased in patients with NASH compared with controls, as demonstrated by reduced suppression of hepatic glucose production and glucose disposal (Gd) rates following insulin infusion. In addition, rates of lipolysis were higher in NASH patients with impaired insulin-mediated suppression of free fatty acid levels. At a tissue specific level, abdominal SAT in patients with NASH was severely insulin resistant, requiring >sixfold more insulin to cause ½-maximal suppression of glycerol release when compared with healthy controls. Furthermore, patients with NASH had significantly higher circulating levels of pro-inflammatory adipocytokines than controls. CONCLUSION: NASH patients have profound IR in the liver, muscle and in particular adipose tissues. This study represents the first in vivo description of dysfunctional SAT in patients with NASH.


Assuntos
Glicerol/metabolismo , Resistência à Insulina , Lipólise , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Gordura Subcutânea Abdominal/metabolismo , Adipocinas/sangue , Adolescente , Adulto , Idoso , Índice de Massa Corporal , Estudos de Casos e Controles , Feminino , Gluconeogênese , Glucose/metabolismo , Técnica Clamp de Glucose , Hemoglobinas Glicadas/metabolismo , Humanos , Hipoglicemiantes/administração & dosagem , Inflamação/metabolismo , Insulina/administração & dosagem , Insulina/metabolismo , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/metabolismo
5.
Pulm Pharmacol Ther ; 27(1): 121-6, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23988443

RESUMO

INTRODUCTION: This study aimed to assess the qualitative and quantitative utility of MRI imaging to illustrate the magnitude and duration of the effect of a standard 100 µg dose of oxymetazoline in a commercially available formulation that also contains aromatic oils. METHODS: This was a randomized, open label, single dose, parallel group study in 21 adult male and female subjects who reported moderate to severe nasal congestion due to acute upper respiratory tract infection or hay fever. MRI scans were acquired using a 3T Philips Achieva scanner with a 16 channel head receive coil. High resolution MRI scans of the nasal turbinates were obtained immediately prior to dosing (baseline) and at approximately 1, 8, 10, 11, and 12 h after dosing. The efficacy variables of primary interest were inferior turbinate total volume at 8 and 12 h post-dosing. The secondary efficacy variables analysed were inferior turbinate total volume at 1, 10, and 11 h post-dosing, middle turbinate total volume at 1, 8, 10, 11, and 12 h post-dosing. RESULTS: Changes from baseline volumes measured for the inferior and middle turbinates of subjects receiving the oxymetazoline formulation showed significant (P < 0.05) decreases at all times up to and including 12 h post-administration. No significant decreases from baseline were detected in subjects receiving a sham 'spray' (untreated control - spray bottles with no spray solution). Statistical ANCOVA results of inferior and middle turbinate volume indicated significant differences (P < 0.05) at all measurement points up to and including 12 h post-administration between the oxymetazoline treatment group and the untreated control with the only exception the middle turbinate volume at 10 h (P = 0.0896). The significant changes were likely to be clinically relevant though this was not measured in the study. No AEs were reported during this study and no other safety evaluations were made. CONCLUSIONS: This study showed that MRI assessment of nasal congestion in human volunteers is a robust, repeatable and viable measurement technique. The application of a 100 µg Vicks Sinex Micromist(®) nasal decongestant (0.05% oxymetazoline solution) delivered a highly significant reduction in inferior and middle turbinate volumes compared with the application of a control, measurable by the MRI method up to and including a 12 h post-dose scan.


Assuntos
Descongestionantes Nasais/uso terapêutico , Obstrução Nasal/tratamento farmacológico , Oximetazolina/uso terapêutico , Administração Intranasal , Adolescente , Adulto , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Descongestionantes Nasais/administração & dosagem , Obstrução Nasal/etiologia , Sprays Nasais , Oximetazolina/administração & dosagem , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Fatores de Tempo , Adulto Jovem
6.
Br J Cancer ; 109(4): 888-90, 2013 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-23880824

RESUMO

BACKGROUND: The prognosis for hepatocellular carcinoma (HCC) is dependent upon tumour stage, performance status (PS), severity of underlying liver disease, and the availability of appropriate therapies. The unavailability of sorafenib may have a significantly adverse effect on the prognosis of UK patients with advanced HCC. During the study period, access to sorafenib was at the discretion of local health funding bodies, a process that may delay or deny access to the drug and that remains in place for Wales, Scotland, and Northern Ireland. Here, we attempt to address the impact of this system on patients with advanced HCC in the United Kingdom. METHODS: This is a retrospective study performed in the two largest specialist hepatobiliary oncology units in the United Kingdom. Funding applications were made to local funding bodies for patients with advanced HCC for whom sorafenib was considered appropriate (advanced HCC not suitable for loco-regional therapies, compensated chronic liver disease, PS 0-2). RESULTS: A total of 133 applications were made, of which 57 (43%) were approved and 76 (57%) declined. Demographics and prognostic factors were balanced between the two groups. This cohort had a number of adverse prognostic features: patients were predominantly PS 1-2; the majority had multifocal disease with the largest lesion being >5 cm; and macroscopic vascular invasion, metastases, and AFP >,000 ng ml(-1), were each present in one-third of cases. The median time from application to funding decision was 17 days (range 3-260 days). For the primary 'intention-to-treat' analysis, median overall survival was 4.1 months when funding was declined, and 9.5 months when funding was approved (hazard ratio (HR) 0.48; 95% CI 0.3186-0.7267; P=0.0005). CONCLUSION: These data support the use of sorafenib for patients with advanced HCC as an effective intervention. In the United Kingdom, this applies to a relatively small group of patients, estimated to total ∼800 per year who, unfortunately, do not survive long enough to themselves lobby for the availability of this drug. These data provide a comparison of sorafenib with supportive care and demonstrate the potential detrimental impact on patient outcomes of rationing health-care resources on the basis of cost.


Assuntos
Antineoplásicos/provisão & distribuição , Carcinoma Hepatocelular/tratamento farmacológico , Alocação de Recursos para a Atenção à Saúde/economia , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Primárias Múltiplas/tratamento farmacológico , Niacinamida/análogos & derivados , Compostos de Fenilureia/provisão & distribuição , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos/economia , Antineoplásicos/uso terapêutico , Carcinoma Hepatocelular/mortalidade , Carcinoma Hepatocelular/patologia , Estudos de Coortes , Feminino , Humanos , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Neoplasias Primárias Múltiplas/patologia , Niacinamida/economia , Niacinamida/provisão & distribuição , Niacinamida/uso terapêutico , Compostos de Fenilureia/economia , Compostos de Fenilureia/uso terapêutico , Estudos Retrospectivos , Sorafenibe , Reino Unido , Adulto Jovem
7.
Eur J Med Genet ; 56(8): 452-7, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23792790

RESUMO

Genomic rearrangements at chromosome 13q31.3q32.1 have been associated with digital anomalies, dysmorphic features, and variable degree of mental disability. Microdeletions leading to haploinsufficiency of miR17∼92, a cluster of micro RNA genes closely linked to GPC5 in both mouse and human genomes, has recently been associated with digital anomalies in the Feingold like syndrome. Here, we report on a boy with familial dominant post-axial polydactyly (PAP) type A, overgrowth, significant facial dysmorphisms and autistic traits who carries the smallest germline microduplication known so far in that region. The microduplication encompasses the whole miR17∼92 cluster and the first 5 exons of GPC5. This report supports the newly recognized role of miR17∼92 gene dosage in digital developmental anomalies, and suggests a possible role of GPC5 in growth regulation and in cognitive development.


Assuntos
Duplicação Cromossômica , Cromossomos Humanos Par 13 , Glipicanas/genética , MicroRNAs/genética , Polidactilia/diagnóstico , Polidactilia/genética , Característica Quantitativa Herdável , Adulto , Hibridização Genômica Comparativa , Fácies , Feminino , Humanos , Lactente , Masculino , Fenótipo , RNA Longo não Codificante
8.
Transplant Proc ; 42(5): 1648-53, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20620493

RESUMO

INTRODUCTION: Age is an established predictor of renal failure among recipients of cadaveric transplants; however, the impact of donor age on recipient glomerular filtration rate (GFR) among living donor kidney (LDK) transplantations is not well established. METHODS: We retrospectively analyzed recipient posttransplantation GFR at 12, 36, and 60 months among 315 LDK allograft recipients. The impact of donor age was assessed on the recipient estimated GFR (eGFR) using multivariate linear regression stratified according to donor age <50 years (n = 246) and >or=50 years (n = 69). RESULTS: Whites comprised the majority of both donors and recipients (77%). The majority (58.4%) of donors were female. Mean age (+/- SD) of the donors was 41.0 +/- 10.2 years (range, 20-65 years). The mean age and body mass index (BMI) of the recipients were 43.3 +/- 12.4 years and 26.0 +/- 4.9, respectively. There was no statistically significant difference in the rejection rate between the 2 groups (P = .571). Mean eGFR at 12 months in the younger group was 63.3 +/- 23.7 compared with 54.8 +/- 19.7 in the older group (P = .015). Similarly, a significant difference was observed at the end of 36 months and 60 months of follow-up (61.5 +/- 23.1 vs 49.4 +/- 18.9, and 59.4 +/- 23.0 vs 45.3 +/- 20.8, respectively; both P = .001). Donor age was a statistically significant predictor of eGFR throughout the study period (P < .05). CONCLUSION: Donor age predicts recipient renal function after living kidney transplantation and needs to be evaluated through a larger prospective investigation.


Assuntos
Taxa de Filtração Glomerular/fisiologia , Transplante de Rim/estatística & dados numéricos , Doadores Vivos/estatística & dados numéricos , Complicações Pós-Operatórias/epidemiologia , Adulto , Quimioterapia Combinada , Feminino , Seguimentos , Rejeição de Enxerto/epidemiologia , Humanos , Imunossupressores/uso terapêutico , Transplante de Rim/efeitos adversos , Transplante de Rim/imunologia , Transplante de Rim/mortalidade , Masculino , Pessoa de Meia-Idade , Insuficiência Renal/epidemiologia , Estudos Retrospectivos , Fatores de Tempo
9.
Oral Microbiol Immunol ; 24(3): 249-54, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19416456

RESUMO

INTRODUCTION: Oral Candida carriage and infection have been reported to be associated with a greater risk for systemic infection in transplant recipients; however, a systematic analysis of the oral Candida titers and species has not been previously conducted. The objectives of this study were to determine the prevalence of oropharyngeal candidiasis, the oral carrier status, Candida titers and species in this population. METHODS: Ninety kidney and heart transplant subjects and 72 age-matched healthy controls were included. Swabs from the oral mucosa and a standardized amount of unstimulated saliva were plated on Chromagar Candida, and colony-forming units per millilitre were calculated. Initial speciation was based on colony color and was confirmed by standard germ tube, biotyping, or polymerase chain reaction assays. RESULTS: Infection with C. albicans was detected in seven transplant subjects and none of the controls. The transplant group had significantly higher oral Candida titers than the control group. There were no statistically significant relationships between the dose or type of immunosuppressants and oral Candida titers or infection. A significantly higher percentage of transplant subjects were colonized by more than one species, compared with control subjects. The most frequent species combination in transplant subjects was C. albicans and C. glabrata. C. glabrata was isolated from 13.5% of transplant carriers and none of the controls. CONCLUSIONS: Increased oral Candida infection and carriage titers were found in the transplant population. Although the majority of transplant patients were colonized by C. albicans, C. glabrata appears to emerge as the second most prevalent species.


Assuntos
Candida/classificação , Candidíase Bucal/diagnóstico , Transplante de Coração , Transplante de Rim , Boca/microbiologia , Antifúngicos/uso terapêutico , Candida albicans/isolamento & purificação , Candida glabrata/isolamento & purificação , Carcinoma de Células Escamosas/complicações , Estudos de Casos e Controles , Compostos Cromogênicos , Contagem de Colônia Microbiana , Ciclosporina/uso terapêutico , Complicações do Diabetes , Feminino , Seguimentos , Humanos , Imunossupressores/uso terapêutico , Masculino , Pessoa de Meia-Idade , Mucosa Bucal/microbiologia , Técnicas de Tipagem Micológica , Prednisona/uso terapêutico , Saliva/microbiologia , Fumar , Abandono do Hábito de Fumar , Língua/microbiologia
10.
Br J Haematol ; 143(3): 349-54, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18759764

RESUMO

A combination of clarithromycin, low dose of thalidomide and low dose dexamethasone was used in a phase II study to treat patients with relapsed and refractory myeloma. Thirty patients received clarithromycin 250 mg twice daily and thalidomide 50 mg at night on an ongoing basis with 4-d pulses of 10 mg dexamethasone given monthly. Eight patients had permitted escalation of thalidomide dosage up to 200 mg daily. The combination was well tolerated and could be given to elderly, infirm and severely cytopenic patients. Response rates were high, with 89% achieving at least 50% reduction in paraprotein and a 96% overall response rate. Although clarithromycin has only minimal anti-myeloma properties when used as a single agent, its combination with thalidomide and dexamethasone appears very effective, allowing these to be used in lower and more tolerable doses with good clinical effects.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Mieloma Múltiplo/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Claritromicina/administração & dosagem , Claritromicina/efeitos adversos , Dexametasona/administração & dosagem , Dexametasona/efeitos adversos , Esquema de Medicação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Qualidade de Vida , Recidiva , Análise de Sobrevida , Talidomida/administração & dosagem , Talidomida/efeitos adversos , Resultado do Tratamento
11.
Int J Bioinform Res Appl ; 3(3): 303-25, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18048194

RESUMO

(my)Grid supports in silico experiments in the life sciences, enabling the design and enactment of workflows as well as providing components to assist service discovery, data and metadata management. The (my)Grid ontology is one component in a larger semantic discovery framework for the identification of the highly distributed and heterogeneous bioinformatics services in the public domain. From an initial model of formal OWL-DL semantics throughout, we now adopt a spectrum of expressivity and reasoning for different tasks in service annotation and discovery. Here, we discuss the development and use of the (my)Grid ontology and our experiences in semantic service discovery.


Assuntos
Biologia Computacional , Software , Interpretação Estatística de Dados , Bases de Dados Factuais , Internet , Semântica
12.
Acta Otorhinolaryngol Ital ; 27(2): 73-7, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17608134

RESUMO

The Common Cold remains the most frequent symptomatic viral infection in man. Current best therapies are all symptomatic. New pharmacological therapies are likely to be prescription-bound, and as most Common Cold infections are successfully treated without the intervention of a Physician, there is a need for effective non-prescription therapy options. Aim of this study is to propose a new type of approach, based on the concept of making a hostile biological environment for virus survival and spreading at the point of infection, the nasopharynx. The hypothesis was advanced that infections could be controlled using a physical biological approach to create an environment at the point of infection, that is inhibitory to the survival, and persistence of infecting virus, and of viruses newly released from infected mucosal epithelial cells. A nasal irrigation spray, designed to deliver a low pH gel to the nasal cavity, was developed and tested in this study. The study was a randomised, parallel, double-blind, placebo-controlled evaluation of three formulations of irrigation nasal spray in 441 subjects. The objective was to test whether the formulations reduced Cold severity and Cold duration compared to a placebo nasal spray. Subjects were recruited, and supplied with the product when healthy, and were instructed to begin treating and recording symptom severity once they experienced the "first signs" of a Common Cold. To qualify, subjects had to volunteer that they had at least one of the symptoms: sore/scratchy throat, runny nose or congested nose. The product was used 4 times daily, with at least 4 hours separating each dose, for a maximum of 7 days. Efficacy was assessed by an Interactive Voice Recall System whereby subjects were required to contact the investigation site, by telephone, twice daily when they were asked to assess the severity of their symptoms using a four point ordinal scale where 0 = "absent", and 3 = "severe". The symptoms assessed were sore throat, runny nose, blocked nose, cough and tired/run-down feeling. Two formulations demonstrated significant effects. A hydroxy methyl propyl cellulose based formulation reduced symptom severity compared with placebo by 17% and a Poloxamer based formulation reduced severity by 21%. Duration of illness was reduced with a hydroxy methyl propyl cellulose based formulation by 1.5 days to 2.4 days (according to the dose) and by a Poloxamer based formulation by 2.5 days. Results of this study suggest that the creation of a non virus-specific, inhibitory environment in the nasopharynx holds promise as an effective method of controlling the severity and duration of the Common Cold.


Assuntos
Celulose/análogos & derivados , Resfriado Comum/prevenção & controle , Resfriado Comum/virologia , Nasofaringe/efeitos dos fármacos , Nasofaringe/virologia , Irrigação Terapêutica/métodos , Adolescente , Adulto , Idoso , Celulose/administração & dosagem , Celulose/farmacologia , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Fatores de Tempo
14.
Math Biosci ; 202(2): 227-47, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16631816

RESUMO

In this paper the inheritance of a Y-linked gene with alleles R and r in a population with both females and males is modelled using a two-type bisexual branching process. It is assumed that the reproductive distribution associated with the R allele can differ from the associated with the r allele and that females prefer to mate with a male having the R allele rather than with a male with the r allele. Under these assumptions, we provide some conditions for the extinction and/or survival of both alleles in the population. These conditions depend on the magnitudes of the average number of females and males per mating unit. Moreover, the almost sure extinction of the r allele is independent of the behaviour of the R allele. On the other hand, the survival of the R allele with positive probability may depend strongly on the reproductive behaviour of the other allele. Theoretical results are illustrated by means of simulated examples and some open problems are proposed to the reader as conjectures.


Assuntos
Genes Ligados ao Cromossomo Y/genética , Modelos Genéticos , Cromossomo Y/genética , Alelos , Animais , Simulação por Computador , Feminino , Humanos , Masculino , Modelos Estatísticos , Processos Estocásticos
15.
J Biotechnol ; 121(3): 410-7, 2006 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-16125265

RESUMO

In industrial fed-batch cultivations it is often necessary to control substrate concentrations at a low level to prevent the production of overflow metabolites and thus optimize the biomass yield. A new method for on-line monitoring and fed-batch control based on fluorescence measurements has been developed. Via instantaneous in situ measurements and multivariate data analysis a chemometric model has been established, which enables the rapid detection of ethanol production at aerobic Saccharomyces cerevisiae fed-batch cultivations. The glucose feed rate is controlled by predicting the metabolic state directly from the fluorescence intensities. Thus, ethanol production could be avoided completely while increasing the biomass yield accordingly. The robust instrumentation is suitable for industrial applications.


Assuntos
Reatores Biológicos/microbiologia , Microbiologia Industrial/métodos , Saccharomyces cerevisiae/metabolismo , Espectrometria de Fluorescência , Aerobiose , Biomassa , Dióxido de Carbono/metabolismo , Técnicas de Cultura de Células , Etanol/metabolismo , Retroalimentação , Fermentação , Glucose/metabolismo , Cinética , Modelos Lineares , Sistemas On-Line , Oxirredução , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Sensibilidade e Especificidade
18.
Transplant Proc ; 35(8): 2873-7, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14697925

RESUMO

BACKGROUND: Itraconazole is often given for fungal prophylaxis to renal transplant recipients, who require concomitant cyclosporine in the immediate posttransplant period. We determined the extent of the pharmacokinetic interaction between cyclosporine and itraconazole oral solution in renal transplant recipients and the effect on daily drug costs. METHOD: This was a single-center, open-label, nonrandomized study. Posttransplantation, renal transplant recipients received itraconazole solution 200 mg twice daily and cyclosporine, dosed to achieve target concentrations. Once at steady state, blood samples were collected over 12 hours for pharmacokinetic evaluation of cyclosporine, itraconazole, and hydroxy-itraconazole. Itraconazole was discontinued after approximately a 3-month prophylaxis regimen. Cyclosporine doses were titrated to achieve target concentrations and cyclosporine concentrations were once again determined when steady state was achieved. A noncompartmental analysis was used to analyze cyclosporine pharmacokinetic parameters. The pharmacoeconomic impact was measured based on the percent change in dose of cyclosporine when administered with and without itraconazole. Drug costs were calculated using the average wholesale price. The cost per patient, as well as the average cost, was calculated for the cyclosporine/itraconazole combination, as well as the cyclosporine regimen alone. RESULTS: Eight renal transplant recipients completed the study. All were included for itraconazole analyses and seven for cyclosporine analyses. Mean peak and trough itraconazole levels were 1.64 +/- 0.82 and 1.23 +/- 0.90 microg/mL respectively. Mean peak and trough hydroxy-itraconazole levels were 2.37 +/- 1.55 and 2.20 +/- 1.48 microg/mL, respectively. While on itraconazole, a 48% reduction in the mean total daily dose of cyclosporine was necessary to maintain target concentrations (171 +/- 63.6 versus 329 +/- 103.5 mg, P =.003). This reduction in cyclosporine dose resulted in a discounted itraconazole daily drug cost of approximately 29.5%. CONCLUSION: Administering itraconazole with cyclosporine allows for a decrease in the cyclosporine dose, thus lowering daily drug costs and providing adequate antifungal coverage with itraconazole and hydroxy-itraconazole trough concentrations above the MIC(90) of Candida and Aspergillus spp.


Assuntos
Ciclosporina/farmacocinética , Ciclosporina/uso terapêutico , Itraconazol/farmacocinética , Itraconazol/uso terapêutico , Transplante de Rim/imunologia , Antifúngicos/farmacocinética , Antifúngicos/uso terapêutico , Relação Dose-Resposta a Droga , Interações Medicamentosas , Humanos , Imunossupressores/farmacocinética , Imunossupressores/uso terapêutico , Micoses/prevenção & controle
19.
Behav Brain Sci ; 24(3): 511-28; discussion 528-73, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11682800

RESUMO

Authors frequently refer to gene-based selection in biological evolution, the reaction of the immune system to antigens, and operant learning as exemplifying selection processes in the same sense of this term. However, as obvious as this claim may seem on the surface, setting out an account of "selection" that is general enough to incorporate all three of these processes without becoming so general as to be vacuous is far from easy. In this target article, we set out such a general account of selection to see how well it accommodates these very different sorts of selection. The three fundamental elements of this account are replication, variation, and environmental interaction. For selection to occur, these three processes must be related in a very specific way. In particular, replication must alternate with environmental interaction so that any changes that occur in replication are passed on differentially because of environmental interaction. One of the main differences among the three sorts of selection that we investigate concerns the role of organisms. In traditional biological evolution, organisms play a central role with respect to environmental interaction. Although environmental interaction can occur at other levels of the organizational hierarchy, organisms are the primary focus of environmental interaction. In the functioning of the immune system, organisms function as containers. The interactions that result in selection of antibodies during a lifetime are between entities (antibodies and antigens) contained within the organism. Resulting changes in the immune system of one organism are not passed on to later organisms. Nor are changes in operant behavior resulting from behavioral selection passed on to later organisms. But operant behavior is not contained in the organism because most of the interactions that lead to differential replication include parts of the world outside the organism. Changes in the organism's nervous system are the effects of those interactions. The role of genes also varies in these three systems. Biological evolution is gene-based (i.e., genes are the primary replicators). Genes play very different roles in operant behavior and the immune system. However, in all three systems, iteration is central. All three selection processes are also incredibly wasteful and inefficient. They can generate complexity and novelty primarily because they are so wasteful and inefficient.


Assuntos
Evolução Biológica , Genética Comportamental , Imunidade/genética , Aprendizagem , Behaviorismo , Condicionamento Operante/fisiologia , Humanos , Aprendizagem/fisiologia , Modelos Biológicos , Biologia Molecular
20.
J Vasc Surg ; 34(1): 139-42, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11436087

RESUMO

BACKGROUND: Dimethyl sulfoxide-cryopreserved cadaveric vein allografts have recently been proposed as an alternative to prosthetic grafts in the problem hemodialysis population. The transfer of mismatched major histocompatibility complex I and II molecules in association with these allografts can potentially lead to allosensitization in nonimmunosuppressed individuals. METHODS: In a university-affiliated medical center, 20 consecutive patients receiving technically successful upper arm cadaveric vein allograft fistulas (CAVFs) for hemodialysis between April 1999 and April 2000 were studied. A control cohort of 20 patients on a kidney transplantation waiting list was selected by nurses blinded to the study. These patients were matched for age, sex, history of transfusion, pregnancy, cause of kidney failure, and prior transplantation. The panel reactive antibody (PRA) values were recorded in this group over the same time period as the CAVF group. RESULTS: Patients receiving CAVFs had a mean PRA assay value of 84.1% (median, 96.5%) at an average of 3.1 months after engraftment (median, 1.5 months). The preengraftment PRA values were available for seven patients who were on the transplant waiting list. Six of these patients had nonreactive PRA assays before CAVF creation. All of these patients converted to positive PRA assays after CAVF creation with a mean value of 92.3% (median, 98%) at 2.85 months follow-up (median, 1.3 months). The mean PRA value for the control cohort was 5.5% (median, 2.5%), with no patients converting from a nonreactive to a reactive PRA assay during this same time interval. CONCLUSION: The use of dimethyl sulfoxide-cryopreserved cadaveric vein allografts for hemodialysis access leads to broad allosensitization as measured by PRA assay. Cryopreserved cadaveric vein allografts should not be used for hemodialysis access in potential kidney transplant recipients.


Assuntos
Derivação Arteriovenosa Cirúrgica , Criopreservação , Transplante de Rim , Adulto , Idoso , Cadáver , Dimetil Sulfóxido , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transplante Homólogo
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