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1.
Earths Future ; 6(11): 1568-1587, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30687769

RESUMO

The California drought of 2012-2016 was a record-breaking event with extensive social, political, and economic repercussions. The impacts were widespread and exposed the difficulty in preparing for the effects of prolonged dry conditions. Although the lessons from this drought drove important changes to state law and policy, there is little doubt that climate change will only exacerbate future droughts. To understand the character of future drought, this paper examines this recent drought period retrospectively and prospectively, that is, as it occurred historically and if similar dynamical conditions to the historical period were to arise 30 years later (2042-2046) subject to the effects of climate change. Simulations were conducted using the Weather Research and Forecasting model using the pseudo global warming method. The simulated historical and future droughts are contrasted in terms of temperature, precipitation, snowpack, soil moisture, evapotranspiration, and forest health. Overall, the midcentury drought is observed to be significantly worse, with many more extreme heat days, record-low snowpack, increased soil drying, and record-high forest mortality. With these findings in mind, the data sets developed in this study provide a means to structure future drought planning around a drought scenario that is realistic and modeled after a memorable historical analog.

2.
Dev Biol (Basel) ; 132: 331-336, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18817322

RESUMO

Toll-like receptor 4 (TLR4) is the key receptor for the LPS component of Gram-negative bacteria. We have identified a SNP within the 5' UTR region of the bovine TLR4 gene at position 226 (c.-226C>G) relative to start codon, which was found to be associated with health related traits in the Canadian Holstein population. TLR4 gene expression was measured over time intervals in samples collected from 18 cows (6 cows in each genotype) challenged in vitro with LPS (20 ng/ml) to determine if this SNP alters the gene expression. TLR4 gene expression was highest 6 h post LPS challenge, and cows with the GG genotype exhibited significantly higher expression compared to other genotypes. This was further validated by a dual luciferase reporter gene assay in which sequential progressive constructs were cloned into the pGL3 basic vector and transfected into bovine Mac-T cells. The reporter construct containing most of the 5' UTR (-456G) exhibited significantly higher luciferase activity compared to-456C, however, further inclusion of 5' upstream sequence showed a reversal phenomenon where the -913C construct exhibited significantly higher activity compared to -913G. These results indicate that the c.-226C>G SNP affects the expression of TLR4, suggesting that this SNP might be influencing the binding and interaction of transcription factors regulating gene expression.


Assuntos
Regiões 5' não Traduzidas , Polimorfismo de Nucleotídeo Único , Receptor 4 Toll-Like/genética , Animais , Sequência de Bases , Bovinos , Primers do DNA , Reação em Cadeia da Polimerase
3.
Clin Pharmacol Ther ; 84(3): 347-61, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18231117

RESUMO

Application of foreign clinical data across geographic regions can accelerate drug development. Drug disposition can be variable, and identification of factors influencing responsible pharmacokinetic/pharmacogenomic approaches could facilitate the universal application of foreign data and reduce the total amount of phase III clinical trials evaluating risks in different populations. Our objective was to establish and compare genotype (major cytochrome P450 (CYP) enzymes)/phenotype associations for Japanese (native and first- and third-generation Japanese living abroad), Caucasian, Chinese, and Korean populations using a standard drug panel. The mean metabolic ratios (MRs) for the four ethnic groups were similar except for a lower activity of CYP2D6 in Caucasians and CYP2C19 in Asians. Genotype, not ethnicity, impacted the MR for CYP2C9, CYP2C19, and CYP2D6; neither affected CYP1A2, CYP2E1, and CYP3A4/5 activities. We conclude that equivalent plasma drug concentrations and metabolic profiles can be expected for native Japanese, first- and third-generation Japanese, Koreans, and Chinese for compounds handled through these six CYP enzymes.


Assuntos
Sistema Enzimático do Citocromo P-450/genética , Genética Populacional , Genótipo , Farmacocinética , Alelos , Ensaios Clínicos Fase III como Assunto , Sistema Enzimático do Citocromo P-450/sangue , Sistema Enzimático do Citocromo P-450/metabolismo , Ásia Oriental , Humanos , Japão , Estudos Multicêntricos como Assunto , População Branca/genética
4.
J Food Prot ; 70(1): 6-10, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17265852

RESUMO

In the United States, foodborne outbreaks of Escherichia coli O157:H7 illness have often been linked to the consumption of contaminated, undercooked ground beef. However, the occurrence of E. coli O157:H7 has also been reported in other farm animals. The objective of this study was to evaluate the occurrence of E. coli O157:H7 on diverse farm types and from a variety of farm samples. Rectal swabs (n=1686) and environmental samples (n=576) were collected from 16 farms in five states over 24 months and analyzed for the presence of E. coli O157:H7. Overall, E. coli O157:H7 was found in 3.6% of beef cattle, 3.4% of dairy cattle, 0.9% of chicken, 7.5% of turkey, and 8.9% of swine samples. The pathogen was isolated sporadically from each of the environmental sample types. Of particular concern was the isolation of E. coli O157:H7 from fresh feed samples, indicating a potential vector for transmission. The data from this study indicate a high occurrence of E. coli O157:H7 on swine and turkey farms. This unexpected result suggests that more research on the occurrence of E. coli O157:H7 on these types of farms is required in order to better understand potential reservoirs of pathogenic E. coli.


Assuntos
Microbiologia Ambiental , Infecções por Escherichia coli/epidemiologia , Escherichia coli O157/isolamento & purificação , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Produtos da Carne/microbiologia , Criação de Animais Domésticos/métodos , Animais , Bovinos , Surtos de Doenças , Reservatórios de Doenças/microbiologia , Reservatórios de Doenças/veterinária , Humanos , Aves Domésticas , Suínos , Estados Unidos/epidemiologia
5.
Foodborne Pathog Dis ; 3(3): 259-65, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16972774

RESUMO

Many of the current studies on the genetic diversity of Escherichia coli O157:H7 have focused on pathogenic clinical, veterinary, or food isolates. These studies did not explore the diversity of the larger population in the farm environment. Research on selected farm isolates address this wider diversity but have typically been limited to a specific geographic locale or farm type, thus giving limited insight into the greater diversity across geographic regions and varied environments. The objective of this study was to evaluate a diverse population of E. coli O157:H7 collected from a variety of locations and farm environments. Eighty-eight isolates were collected from four farm types (swine, dairy, beef, and poultry) across the southeastern and western United States. Eighteen farms were sampled every 3 months over a period of 24 months. Isolates were analyzed by ribotyping and pulsed field gel electrophoresis (PFGE). Real-time PCR was used to determine the presence or absence of key pathogenic genes (stx1, stx2, and eae). The data indicate a significant amount of genetic diversity, however, ribotype analysis revealed meaningful clusters within the larger population. These groupings were consistent with PFGE analysis. Most of these isolates were clustered by location (i.e. from the same state or region) or farm type. Of the isolates in these clusters, most did not contain pathogenic genes. Of notable interest is a single group in which the majority of isolates, collected from four of the five states sampled, contained at least one stx gene and the eae gene suggesting the existence of a specific pathogenic cluster. These data suggest that, while there is notable diversity within the broader E. coli O157:H7 population, pathogenic isolates may be limited to a subset of strains within the population.


Assuntos
Microbiologia Ambiental , Escherichia coli O157/classificação , Escherichia coli O157/genética , Variação Genética , Filogenia , Fatores de Virulência/análise , Criação de Animais Domésticos/métodos , Animais , Análise por Conglomerados , Eletroforese em Gel de Campo Pulsado , Escherichia coli O157/patogenicidade , Reação em Cadeia da Polimerase , Ribotipagem , Toxinas Shiga/biossíntese , Sudeste dos Estados Unidos , Sudoeste dos Estados Unidos
6.
Dev Dyn ; 235(5): 1390-9, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16552759

RESUMO

Wnt signalling regulates many developmental processes, including the fate specification, polarity, migration, and proliferation of cranial neural crest. The canonical Wnt pathway has also been shown to play an important role in bone physiology and there is evidence for its recapitulation during organ regeneration in lower vertebrates. This study explores the role of the Wnt signalling pathway in deer antlers, frontal bone appendages that are the only mammalian organs capable of regeneration. Immunocytochemistry was used to map the distribution of the activated form of beta-catenin ((a)betaCAT). A low level of (a)betaCAT staining was detected in chondrocytes and in osteoblasts at sites of endochondral bone formation. However, (a)betaCAT was localised in cellular periosteum and in osteoblasts in intramembranous bone, where it co-localised with osteocalcin. The most intense (a)betaCAT staining was in dividing undifferentiated cells in the mesenchymal growth zone. Antler progenitor cells (APCs) were cultured from this region and when the canonical Wnt pathway was inhibited at the level of Lef/TCF by epigallocatechin gallate (EGCG), the cell number decreased. TUNEL staining revealed that this was as a result of increased apoptosis. Activation of the pathway by lithium chloride (LiCl) had no effect on cell number but inhibited alkaline phosphate activity (ALP), a marker of APC differentiation, whereas EGCG increased ALP activity. This study demonstrates that beta-catenin plays an important role in the regulation of antler progenitor cell survival and cell fate. It also provides evidence that beta-catenin's function in regulating bone formation by osteoblasts may be site-specific.


Assuntos
Chifres de Veado/crescimento & desenvolvimento , Cervos/crescimento & desenvolvimento , Regeneração/fisiologia , Transdução de Sinais/fisiologia , Proteínas Wnt/fisiologia , Animais , Chifres de Veado/citologia , Chifres de Veado/fisiologia , Proliferação de Células , Sobrevivência Celular/fisiologia , Cervos/fisiologia , Masculino , Células-Tronco/citologia , Células-Tronco/fisiologia , beta Catenina/biossíntese , beta Catenina/genética , beta Catenina/metabolismo
7.
J Anat ; 207(5): 603-18, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16313394

RESUMO

Many organisms are able to regenerate lost or damaged body parts that are structural and functional replicates of the original. Eventually these become fully integrated into pre-existing tissues. However, with the exception of deer, mammals have lost this ability. Each spring deer shed antlers that were used for fighting and display during the previous mating season. Their loss is triggered by a fall in circulating testosterone levels, a hormonal change that is linked to an increase in day length. A complex 'blastema-like' structure or 'antler-bud' then forms; however, unlike the regenerative process in the newt, most evidence (albeit indirect) suggests that this does not involve reversal of the differentiated state but is stem cell based. The subsequent re-growth of antlers during the spring and summer months is spectacular and represents one of the fastest rates of organogenesis in the animal kingdom. Longitudinal growth involves endochondral ossification in the tip of each antler branch and bone growth around the antler shaft is by intramembranous ossification. As androgen concentrations rise in late summer, longitudinal growth stops, the skin (velvet) covering the antler is lost and antlers are 'polished' in preparation for the mating season. Although the timing of the antler growth cycle is clearly closely linked to circulating testosterone, oestrogen may be a key cellular regulator, as it is in the skeleton of other male mammals. We still know very little about the molecular machinery required for antler regeneration, although there is evidence that developmental signalling pathways with pleiotropic functions are important and that novel 'antler-specific' molecules may not exist. Identifying these pathways and factors, deciphering their interactions and how they are regulated by environmental cues could have an important impact on human health if this knowledge is applied to the engineering of new human tissues and organs.


Assuntos
Chifres de Veado/crescimento & desenvolvimento , Cervos/embriologia , Regeneração/fisiologia , Androgênios/fisiologia , Animais , Desenvolvimento Ósseo/fisiologia , Reabsorção Óssea , Cartilagem/crescimento & desenvolvimento , Mamíferos/fisiologia , Modelos Animais
8.
Mol Ther ; 4(3): 192-200, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11545609

RESUMO

The X-linked bleeding disorder hemophilia B is caused by absence of functional blood coagulation factor IX (F9) and can be treated by adeno-associated viral (AAV) mediated gene transfer to skeletal muscle. The safety of this approach is currently being evaluated in a phase I clinical trial. Efficacy of this and several other gene therapy strategies has been addressed in hemophilia B dogs, an important preclinical model of the disease. While previously published data demonstrated sustained expression of canine F9 in dogs with a missense mutation in the gene F9, we show here that AAV-mediated canine F9 gene transfer to skeletal muscle of hemophilia B dogs carrying a null mutation of F9 (causing an early stop codon and an unstable mRNA) results in induction of inhibitory anti-canine F9 at comparable vector doses (1 x 10(12) vector genomes/kg). Thus, the risk of inhibitor formation following AAV-mediated F9 gene therapy may be influenced by the nature of the underlying mutation in F9. Transient immune suppression with cyclophosphamide at the time of vector administration blocked formation of anti-canine F9 antibodies in the one animal treated with this approach. Treatment with this combination of gene transfer and transient immune modulation has resulted in sustained expression (>8 months) of canine F9 at levels sufficient for partial correction of coagulation parameters.


Assuntos
Fator IX/uso terapêutico , Deleção de Genes , Terapia Genética/métodos , Hemofilia B/genética , Hemofilia B/terapia , Imunossupressores/farmacologia , Músculo Esquelético/metabolismo , Adenoviridae/genética , Animais , Anticorpos/imunologia , Western Blotting , Ciclofosfamida/farmacologia , Doenças do Cão/genética , Doenças do Cão/terapia , Cães , Fator IX/genética , Fator IX/imunologia , Fator IX/farmacologia , Expressão Gênica/efeitos dos fármacos , Técnicas de Transferência de Genes , Vetores Genéticos/administração & dosagem , Vetores Genéticos/genética , Hemofilia B/imunologia , Hemofilia B/veterinária , Injeções Intramusculares , Masculino , Fatores de Tempo
9.
J Food Prot ; 64(9): 1425-9, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11563522

RESUMO

The efficacy of sucrose combined with CaCl2 during osmotic dehydration (OD) was tested for the control of Botrytis cinerea, Colletotrichum acutatum, and Penicillium expansum growth on lightly processed apple slices. The objective of this work was to determine whether the addition of CaCl2 in the osmotic solutions would limit the proliferation of fungal decay organisms. Slices were submitted to OD for 1 h at 25 degrees C in solutions containing 5 to 65% sucrose. Calcium chloride was added to a similar set of sucrose solutions at 0 to 8%. Control slices were made of untreated slices, and slices were processed in water. The mass ratio of the slices did not vary when fruit pieces were processed in solutions containing 5 to 65% sucrose. These slices showed a high susceptibility to spoilage compared to the control slices not submitted to OD: a significant twofold and 60% increase in decay area caused by B. cinerea and P. expansum, respectively, was observed when slices were processed in 50% sucrose/0% CaCl2; C. acutatum showed a significant 50% increase in decay area when slices were processed in 20% sucrose/0% CaCl2. Calcium uptake was significantly increased when slices were processed in CaCl2 solutions, and the highest Ca content was observed when processed in 8% CaCl2, reaching 40 times that of the control slices processed in water. Calcium-treated slices were less susceptible to spoilage by all three pathogens, and the most effective combination in reducing apple slice spoilage was 20 to 30% sucrose combined with 2% CaCl2.


Assuntos
Cloreto de Cálcio/farmacologia , Conservação de Alimentos/métodos , Fungos/efeitos dos fármacos , Rosales/metabolismo , Sacarose/farmacologia , Desidratação , Osmose , Soluções , Resultado do Tratamento
10.
J Food Prot ; 64(7): 1019-24, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11456186

RESUMO

The beneficial health effects of extracts from many types of plants that are used as seasoning agents in foods and beverages have been claimed for centuries. The purpose of this study was to examine the effectiveness of selected herb and spice essential oils for control of growth and survival of microorganisms. Inhibition of growth was tested by the paper disc agar diffusion method. Antibiotic susceptibility discs were used as control. Minimum lethal concentration (MLC) was determined by the tube dilution method. Essential oils from anise, angelica, basil, carrot, celery, cardamom, coriander, dill weed, fennel, oregano, parsley, and rosemary were evaluated. Inhibition ranged from complete with oregano to no inhibition with carrot oil for each of the test strains that included: Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O:157:H7, Yersinia enterocolitica, Pseudomonas aeruginosa, Lactobacillus plantarum, Aspergillus niger, Geotrichum, and Rhodotorula. Oregano essential oil showed the greatest inhibition (zone, > or = 70 to 80 mm) (MLC, approximately 8 ppm). Coriander and basil were also highly inhibitory (MLC, approximately 25 to 50 ppm) to E. coli O:157:H7 and to the other bacteria and fungi tested. Anise oil was not particularly inhibitory to bacteria (inhibition zone, approximately 25 mm); however, anise oil was highly inhibitory to molds. Because some of the herbal and spice essential oils are highly inhibitory to selected pathogenic and spoilage microorganisms, they may provide alternatives and supplements to conventional antimicrobial additives in foods.


Assuntos
Bactérias/efeitos dos fármacos , Conservação de Alimentos , Extratos Vegetais/farmacologia , Óleos de Plantas/farmacologia , Apiaceae , Bactérias/crescimento & desenvolvimento , Microbiologia de Alimentos , Imunodifusão , Magnoliopsida/química , Testes de Sensibilidade Microbiana , Óleos Voláteis/farmacologia
11.
J Orthop Sports Phys Ther ; 31(7): 375-83, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11451308

RESUMO

STUDY DESIGN: Descriptive. OBJECTIVE: To describe upper body postures and movements that occur when an individual with visual impairment uses a cane to explore the environment while walking. BACKGROUND: Previous research revealed self-reported neuromusculoskeletal problems related to cane use in individuals with visual impairments. No research, however, is available correlating neuromusculoskeletal problems with specific strategies of cane use or describing what movements and postures actually occur during cane use. METHODS AND MEASURES: Twenty-eight individuals with visual impairment who had been walking independently with a long cane for >1 year were videotaped walking with their canes. Subjects included 16 men and 12 women with a mean age of 39.8 +/- 15.2. Postures and movements of the head and neck, trunk, and each upper extremity body segment were analyzed using videotape. RESULTS: Thirty-nine categories of postures or repetitive joint movements were observed. Half of the subjects lacked intersegmental movement of the head, trunk, and shoulder girdles during walking. The repetitive movements used to manipulate the cane occurred at the forearm or wrist. Intrasubject variability of postures and movements was low. CONCLUSIONS: A variety of sustained postures and repetitive movements occur among individuals using long canes. Each individual displays minimal variability in cane manipulation strategy when walking in an uncomplicated environment. Cane manipulation is accomplished by repetitive movements of wrist flexion/extension, wrist ulnar/radial deviation, or forearm pronation/supination. The remainder of the upper body maintains sustained postures, and more than half of long cane users lack the normal intersegmental movement that typically occurs in the neck, trunk, and shoulder girdle during walking. Further research is needed to determine whether particular cane manipulation strategies or sustained postures during cane use increase the risk of musculoskeletal pain syndromes.


Assuntos
Cegueira/reabilitação , Bengala , Movimento/fisiologia , Postura/fisiologia , Adolescente , Adulto , Idoso , Braço/fisiologia , Transtornos Traumáticos Cumulativos/epidemiologia , Feminino , Lateralidade Funcional/fisiologia , Marcha/fisiologia , Força da Mão , Humanos , Masculino , Pessoa de Meia-Idade , Pescoço/fisiologia
12.
Psychiatr Serv ; 52(5): 666-72, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11331803

RESUMO

OBJECTIVE: The study examined the relationship between treatment cultures of nursing homes and their responses to regulations to reduce use of psychotropic drugs mandated by the 1987 Omnibus Budget Reconciliation ACT: The authors hypothesized that reduction in use of antipsychotic drugs was more likely to occur in homes with a resident-centered culture emphasizing psychosocial care, avoidance of psychotropic drugs, pharmacist feedback, and involvement of mental health workers. The authors also predicted greater reductions in drug use in facilities with a less severe case mix and better capacity for change. METHODS: Data were collected in a stratified random sample of 16 skilled nursing facilities in Wisconsin. Participants included 1,181 residents in the baseline study and 1,650 residents in the follow-up study. Treatment culture was measured with a questionnaire for assessing nurses' beliefs and philosophies of care and their interactions with pharmacists and mental health workers. RESULTS: No significant change was observed in the use of benzodiazepines, antidepressants, or polymedicine (two or more psychotropic medications). However, use of antipsychotic drugs decreased significantly, from 24 percent to 16 percent. The change in use varied dramatically across facilities, from an 85 percent reduction to a 19 percent increase. Findings also revealed significant variability in treatment cultures. Greater reductions in use of antipsychotic drugs were found in facilities with a resident-centered culture, a less severe case mix, and a higher nurse-to-resident staffing ratio. CONCLUSIONS: Future policy and quality improvement efforts must address treatment cultures, staffing, and other organizational barriers to nursing home reform.


Assuntos
Uso de Medicamentos/estatística & dados numéricos , Sistemas de Medicação/estatística & dados numéricos , Transtornos Mentais/tratamento farmacológico , Recursos Humanos de Enfermagem/psicologia , Cultura Organizacional , Psicotrópicos/provisão & distribuição , Instituições de Cuidados Especializados de Enfermagem/normas , Idoso , Atitude do Pessoal de Saúde , Coleta de Dados , Uso de Medicamentos/legislação & jurisprudência , Feminino , Fidelidade a Diretrizes , Humanos , Masculino , Medicaid , Assistência Centrada no Paciente , Instituições de Cuidados Especializados de Enfermagem/legislação & jurisprudência , Instituições de Cuidados Especializados de Enfermagem/estatística & dados numéricos , Wisconsin
13.
J Am Geriatr Soc ; 49(12): 1673-8, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11844002

RESUMO

OBJECTIVES: To assess the overall prescribing and chronic use of benzodiazepines (BZs) in nursing homes before and after implementation of BZ guidelines by the Health Care Finance Administration (HCFA). A second aim was to identify facility predictors of BZ prescribing and chronic use after guideline implementation. DESIGN: Nonexperimental, observational study design. SETTING: Drug use was assessed in 16 randomly selected skilled nursing facilities in Wisconsin before 1990 and again in 1993-1994. PARTICIPANTS: One thousand one hundred eighty-one Medicaid-funded residents at baseline and 1,650 Medicaid-funded residents at follow-up. MEASUREMENTS: Drug use measures included percentage of residents with prescribed BZs and percentage of residents with chronic BZ use (defined as >or=4 months of continuous use). A 4-month cutoff was used because HCFA guidelines consider this length of continuous use to be potentially excessive. Facility predictors of drug use included resident demographic and diagnostic mix, size, ownership, Medicaid per diem, and nurse staffing. RESULTS: Before 1990, one-fourth of all residents were prescribed a BZ and nearly one-tenth of all residents had chronic BZ use. Federal guidelines had nonsignificant effects on these measures; BZ prescribing declined only 3.6% (26.4-22.8%) and chronic use declined only 1.3% (9.2-7.9%). Regression results showed that overall prescribing at follow-up was higher in facilities with more female residents (beta= .52, P= .018) and residents with psychiatric disorders (beta= .41, P= .045). However, nurse staffing was the only significant predictor of chronic BZ use. As expected, better nurse staffing was associated with lower rates of chronic use (beta= -0.46, P= .037). CONCLUSION: Efforts to improve BZ use in nursing homes must address the need for better nurse staffing and better assessment and management of psychiatric disorders that can trigger BZ prescribing.


Assuntos
Benzodiazepinas/administração & dosagem , Benzodiazepinas/normas , Centers for Medicare and Medicaid Services, U.S./normas , Prescrições de Medicamentos/normas , Transtornos Mentais/tratamento farmacológico , Casas de Saúde/normas , Recursos Humanos de Enfermagem/normas , Guias de Prática Clínica como Assunto/normas , Características de Residência , Idoso , Idoso de 80 Anos ou mais , Benzodiazepinas/uso terapêutico , Feminino , Seguimentos , Humanos , Masculino , Padrões de Prática Médica/normas , Valor Preditivo dos Testes , Distribuição Aleatória , Fatores de Tempo , Estados Unidos
15.
J Chem Inf Comput Sci ; 40(3): 701-5, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10850774

RESUMO

The use of combinatorial chemistry has become commonplace within the pharmaceutical industry. Less widespread but gaining in popularity is the derivation of activity models from the high-throughput assays of these libraries. Such models are then used as filters during the design of refined daughter libraries. The design of these second generation libraries, which efficiently test and conform to the derived activity model from the large space of virtual possibilities, remains an area of considerable research. We present here a computationally efficient method for the design of optimally dense (in model matching compounds) synthetic matrices from in silico virtual libraries.

16.
J Mol Graph Model ; 18(4-5): 335-42, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11143553

RESUMO

We describe statistical techniques for effective evaluation of large virtual combinatorial libraries (> 10(10) potential compounds). The methods described are used for computationally evaluating templates (prioritization of candidate libraries for synthesis and screening) and for the design of individual combinatorial libraries (e.g., for a given diversity site, reagents can be selected based on the estimated frequency with which they appear in products that pass a computational filter). These statistical methods are powerful because they provide a simple way to estimate the properties of the overall library without explicitly enumerating all of the possible products. In addition, they are fast and simple, and the amount of sampling required to achieve a desired precision is calculable. In this article, we discuss the computational methods that allow random product selection from a combinatorial library and the statistics involved in estimating errors from quantities obtained from such samples. We then describe three examples: (1) an estimate of average molecular weight for the several billion possible products in a four-component Ugi reaction, a quantity that can be calculated exactly for comparison; (2) the prioritization of four templates for combinatorial synthesis using a computational filter based on four-point pharmacophores; and (3) selection of reagents for the four-component Ugi reaction based on their frequency of occurrence in products that pass a pharmacophore filter.


Assuntos
Técnicas de Química Combinatória , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Avaliação Pré-Clínica de Medicamentos/estatística & dados numéricos , Indicadores e Reagentes , Peso Molecular
17.
J Med Chem ; 42(1): 60-6, 1999 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-9888833

RESUMO

IcePick is a system for computationally selecting diverse sets of molecules. It computes the dissimilarity of the surface-accessible features of two molecules, taking into account conformational flexibility. Then, the intrinsic diversity of an entire set of molecules is calculated from a spanning tree over the pairwise dissimilarities. IcePick's dissimilarity measure is compared against traditional 2D topological approaches, and the spanning tree diversity measure is compared against commonly used variance techniques. The method has proven easy to implement and is fast enough to be used in selection of reactants for numerous production-sized combinatorial libraries.


Assuntos
Desenho de Fármacos , Modelos Moleculares , Conformação Molecular , Relação Estrutura-Atividade
18.
Phys Ther ; 78(9): 999-1006, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9736897

RESUMO

BACKGROUND AND PURPOSE: The purpose of this study was to describe the movement patterns (MPs) in young adults moving supine from the foot to the head of a bed. SUBJECTS: Thirty-six young adults, aged 19 through 44 years, participated in this study. METHODS: Subjects were videotaped performing 10 trial of moving in bed. The MPs of 3 body regions were described and categorized. RESULTS: Six MP categories were developed for the axial region, 8 MP categories were developed for the upper extremities, and 6 MP categories were developed for the lower extremities. Kappa values ranged from .81 to .90 for the 3 body regions, Fifty-nine different combinations of MPs were observed. The most common combination of MPs occurred in 21.2% of the trials, 3 times more frequently than any other combination. CONCLUSION AND DISCUSSION: A variety of MPs are used by young adults for moving from the foot to the head of the bed. A symmetrical pattern of sitting up and pushing with both hands and both feet was found to be the most common pattern. [Cohen BG, Cardillo ER, Lugg D, et al. Description of movement patterns of young adults moving supine from the foot to the head of the bed.


Assuntos
Leitos , Movimento , Decúbito Dorsal/fisiologia , Adulto , Feminino , Humanos , Masculino , Philadelphia , Reprodutibilidade dos Testes , Gravação de Videoteipe
19.
Biol Chem ; 379(2): 225-9, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9524076

RESUMO

We have identified a hirudin-sensitive proteinase from human fibroblasts. Inhibition of this enzyme results in partial inhibition of cell growth in culture. The enzyme has a molecular weight of about 38000, and can be isolated by affinity chromatography with a hirudin-agarose matrix. The enzyme is apparently not closely related to thrombin, but does show a high level of amino acid sequence homology with fragments of a protein isolated from the synovial fluid of rheumatoid arthritis patients, which acts as a mitogen for human T lymphocytes.


Assuntos
Endopeptidases/metabolismo , Fibroblastos/enzimologia , Hirudinas/farmacologia , Inibidores de Proteases/farmacologia , Sequência de Aminoácidos , Endopeptidases/efeitos dos fármacos , Endopeptidases/isolamento & purificação , Humanos , Dados de Sequência Molecular
20.
Percept Mot Skills ; 83(3 Pt 1): 723-32, 1996 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8961309

RESUMO

The effect of learning a throwing skill with the body in one position on performing the skill in a different position was investigated. 40 normal women, aged 20 to 34 years, were randomly assigned to experimental or control groups. Subjects threw darts from two positions, sitting on a Balans chair or reclined on a slanted table. Practice and transfer sessions each included 4 sets of 5 throws. Performance was significantly poorer after switching positions than when remaining in the same position. Performance after practice in an alternate position was significantly worse than performance after no practice. These findings suggest that practicing a skill in one position may not improve learners' ability to perform that skill in a different position.


Assuntos
Habituação Psicofisiológica , Orientação , Desempenho Psicomotor , Transferência de Experiência , Adulto , Feminino , Generalização Psicológica , Humanos , Postura
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