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1.
Proc Natl Acad Sci U S A ; 120(39): e2303455120, 2023 09 26.
Artículo en Inglés | MEDLINE | ID: mdl-37722054

RESUMEN

Cows produce antibodies with a disulfide-bonded antigen-binding domain embedded within ultralong heavy chain third complementarity determining regions. This "knob" domain is analogous to natural cysteine-rich peptides such as knottins in that it is small and stable but can accommodate diverse loops and disulfide bonding patterns. We immunized cattle with SARS-CoV-2 spike and found ultralong CDR H3 antibodies that could neutralize several viral variants at picomolar IC50 potencies in vitro and could protect from disease in vivo. The independent CDR H3 peptide knobs were expressed and maintained the properties of the parent antibodies. The knob interaction with SARS-CoV-2 spike was revealed by electron microscopy, X-ray crystallography, NMR spectroscopy, and mass spectrometry and established ultralong CDR H3-derived knobs as the smallest known recombinant independent antigen-binding fragment. Unlike other vertebrate antibody fragments, these knobs are not reliant on the immunoglobulin domain and have potential as a new class of therapeutics.


Asunto(s)
COVID-19 , SARS-CoV-2 , Femenino , Animales , Bovinos , Anticuerpos , Fragmentos Fab de Inmunoglobulinas/genética , Disulfuros
2.
Drug Dev Res ; 82(7): 873-879, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34110032

RESUMEN

COVID-19 manifests as a mild disease in most people but can progress to severe disease in nearly 20% of individuals. Disease progression is likely driven by a cytokine storm, either directly stimulated by SARS-CoV-2 or by increased systemic inflammation in which the gut might play an integral role. SARS-CoV-2 replication in the gut may cause increased intestinal permeability, alterations to the fecal microbiome, and increased inflammatory cytokines. Each effect may lead to increased systemic inflammation and the transport of cytokines and inflammatory antigens from the gut to the lung. Few interventions are being studied to treat people with mild disease and prevent the cytokine storm. Serumderived bovine immunoglobulin/protein isolate (SBI) may prevent progression by (1) binding and neutralizing inflammatory antigens, (2) decreasing gut permeability, (3) interfering with ACE2 binding by viral proteins, and (4) improving the fecal microbiome. SBI is therefore a promising intervention to prevent disease progression in COVID-19 patients.


Asunto(s)
Tratamiento Farmacológico de COVID-19 , Inmunización Pasiva/métodos , Enzima Convertidora de Angiotensina 2/metabolismo , Animales , COVID-19/complicaciones , Bovinos , Síndrome de Liberación de Citoquinas/etiología , Síndrome de Liberación de Citoquinas/prevención & control , Microbioma Gastrointestinal , Tracto Gastrointestinal/patología , Humanos , Permeabilidad
3.
Crit Rev Biotechnol ; 39(3): 351-365, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30727764

RESUMEN

Emerging technologies research often covers various perspectives in disciplines and research areas ranging from hard sciences, engineering, policymaking, and sociology. However, the interrelationship between these different disciplinary domains, particularly the physical and social sciences, often occurs many years after a technology has matured and moved towards commercialization. Synthetic biology may serve an exception to this idea, where, since 2000, the physical and the social sciences communities have increasingly framed their research in response to various perspectives in biological engineering, risk assessment needs, governance challenges, and the social implications that the technology may incur. This paper reviews a broad collection of synthetic biology literature from 2000-2016, and demonstrates how the co-development of physical and social science communities has grown throughout synthetic biology's earliest stages of development. Further, this paper indicates that future co-development of synthetic biology scholarship will assist with significant challenges of the technology's risk assessment, governance, and public engagement needs, where an interdisciplinary approach is necessary to foster sustainable, risk-informed, and societally beneficial technological advances moving forward.


Asunto(s)
Bioingeniería/tendencias , Política Pública/tendencias , Sociología/tendencias , Biología Sintética/tendencias , Humanos , Investigación/tendencias , Ciencias Sociales
4.
Chirality ; 29(1): 5-9, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27933649

RESUMEN

Amyloid beta-protein 42 plays an important role in the onset and progression of Alzheimer's disease. Familial mutations have identified the glutamate residue 22 as a hotspot with regard to peptide neurotoxicity. We introduce an approach to study the influence of systematic sidechain modification at this residue, employing chirality as a structural probe. Circular dichroism experiments reveal that charge-preserving alterations of the amino acid sidechain attenuate the characteristic random coil to ß-sheet transition associated with the wildtype peptide. Removal of the negative charge from residue 22, a trait observed with all known familial mutations at this residue, gives rise to a peptide with limited random coil propensity and high ß-sheet characteristics. Our approach can be extended to other residues of Aß, as well as further amyloidogenic peptides.


Asunto(s)
Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/química , Secuencia de Aminoácidos , Péptidos beta-Amiloides/metabolismo , Dicroismo Circular , Humanos , Mutación , Estructura Secundaria de Proteína , Estereoisomerismo , Relación Estructura-Actividad
5.
Skeletal Radiol ; 46(3): 333-341, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28070625

RESUMEN

PURPOSE: To create a timetable for dating long bone fractures in infants aged less than 1 year using previously defined radiographic signs of fracture healing. MATERIALS AND METHODS: A retrospective cross-sectional time series of long bone fractures in infants aged less than 1 year was conducted from 2006 to 2013. After exclusion criteria were applied 59 digital image series were available for review from 40 infants. Utilizing published criteria for dating fractures, the presence or absence of four pre-defined features of healing was scored: periosteal reaction, callus, bridging, and remodeling. Three radiologists independently scored radiographs with a 3-point scale, marking each feature as present, absent, or equivocal. The times in days when features were first seen, peaked (feature agreed present in >40% of images), and last seen were noted. Statistical analysis using free marginal kappa was conducted. RESULTS: The level of agreement among the three radiologists was high (0.64-0.85). The sequence in which the features were seen was: periosteal reaction range 7-130 (present in the majority of cases between 9 and 49 days); callus range 9-130 (present in the majority of cases between days 9-26); bridging range 15-130 (seen in the majority of cases between 15 and 67 days); remodeling range 51-247 days. CONCLUSION: This study provides a timetable of radiological features of long bone healing among young infants for the first time. Dating of incomplete long bone fractures is challenging, beyond the presence of periosteal reaction, but a consistent sequence of changes is present in complete fractures.


Asunto(s)
Remodelación Ósea/fisiología , Maltrato a los Niños/diagnóstico , Curación de Fractura/fisiología , Fracturas Óseas/diagnóstico por imagen , Extremidad Inferior/diagnóstico por imagen , Extremidad Superior/diagnóstico por imagen , Estudios Transversales , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Estudios Retrospectivos
6.
Angew Chem Int Ed Engl ; 56(38): 11506-11510, 2017 09 11.
Artículo en Inglés | MEDLINE | ID: mdl-28682473

RESUMEN

Racemates often have lower solubility than enantiopure compounds, and the mixing of enantiomers can enhance the aggregation propensity of peptides. Amyloid beta (Aß) 42 is an aggregation-prone peptide that is believed to play a key role in Alzheimer's disease. Soluble Aß42 aggregation intermediates (oligomers) have emerged as being particularly neurotoxic. We hypothesized that the addition of mirror-image d-Aß42 should reduce the concentration of toxic oligomers formed from natural l-Aß42. We synthesized l- and D-Aß42 and found their equimolar mixing to lead to accelerated fibril formation. Confocal microscopy with fluorescently labeled analogues of the enantiomers showed their colocalization in racemic fibrils. Owing to the enhanced fibril formation propensity, racemic Aß42 was less prone to form soluble oligomers. This resulted in the protection of cells from the toxicity of l-Aß42 at concentrations up to 50 µm. The mixing of Aß42 enantiomers thus accelerates the formation of non-toxic fibrils.


Asunto(s)
Péptidos beta-Amiloides/síntesis química , Péptidos beta-Amiloides/química , Péptidos beta-Amiloides/farmacología , Animales , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Humanos , Microscopía Confocal , Células PC12 , Ratas , Estereoisomerismo , Relación Estructura-Actividad
7.
Chemistry ; 22(34): 11967-70, 2016 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-27272258

RESUMEN

The amyloid beta peptide 42 (Aß42) is an aggregation-prone peptide that plays a pivotal role in Alzheimer's disease. We report that a subtle perturbation to the peptide through a single chirality change at glutamate 22 leads to a pronounced delay in the ß-sheet adoption of the peptide. This was accompanied by an attenuated propensity of the peptide to form fibrils, which was correlated with changes at the level of the fibrillary architecture. Strikingly, the incorporation of d-glutamate was found to stabilize a soluble, ordered macromolecular assembly with enhanced cytotoxicity to PC12 cells, highlighting the importance of advanced prefibrillary Aß aggregates in neurotoxicity.


Asunto(s)
Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/química , Péptidos beta-Amiloides/toxicidad , Ácido Glutámico/química , Fragmentos de Péptidos/química , Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides/metabolismo , Animales , Humanos , Células PC12 , Fragmentos de Péptidos/metabolismo , Ratas
8.
Curr Psychiatry Rep ; 17(7): 54, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25980511

RESUMEN

Military sexual assault is a pervasive problem throughout the military services, despite numerous initiatives to end it. No doubt the military's lack of progress stems from the complexity of sexual assaults, yet in order to develop effective strategies and programs to end sexual assault, deep understanding and appreciation of these complexities are needed. In this paper, we describe the root causes and numerous myths surrounding sexual assault, the military cultural factors that may unintentionally contribute to sexual assault, and the uncomfortable issues surrounding sexual assault that are often ignored (such as the prevalence of male sexual assault within the military). We conclude by offering a broad, yet comprehensive set of recommendations that considers all of these factors for developing effective strategies and programs for ending sexual assault within in the military.


Asunto(s)
Personal Militar , Cultura Organizacional , Poder Psicológico , Violación , Sexismo , Acoso Sexual , Adulto , Consumo de Bebidas Alcohólicas , Femenino , Identidad de Género , Homosexualidad Masculina , Humanos , Masculino , Personal Militar/psicología , Personal Militar/estadística & datos numéricos , Innovación Organizacional , Prevalencia , Violación/prevención & control , Violación/psicología , Violación/estadística & datos numéricos , Acoso Sexual/prevención & control , Acoso Sexual/psicología , Acoso Sexual/estadística & datos numéricos , Estereotipo , Estados Unidos/epidemiología , Adulto Joven
9.
Acad Psychiatry ; 39(4): 372-5, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26122348

RESUMEN

OBJECTIVE: Maintenance of an academic focus is difficult for military residents transitioning into their first duty assignment. METHOD: Building upon previous work on this subject, the authors present an updated and expanded junior faculty development model organized around seven overlapping domains: mentorship, scholarship, research, career planning, openness to experience, networking with other disciplines, and responsibility seeking. Using these seven domains as a platform for discussion, the authors focus on challenges facing early-career military psychiatrists and provide guidance based upon personal experience and limited applicable research. RESULTS: The authors believe that highly successful early-career psychiatrists wishing to maintain an academic focus possess a proactive attitude, obtain skillful mentoring, work well with others, and are able to adapt to new environments. CONCLUSION: Through conscious planning and goal setting, they are able to capitalize on opportunities as they become available.


Asunto(s)
Selección de Profesión , Docentes Médicos , Internado y Residencia , Personal Militar , Psiquiatría Militar , Humanos , Mentores
10.
Curr Psychiatry Rep ; 16(9): 467, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25023512

RESUMEN

As the longest war in American history draws to a close, an unprecedented number of service members and veterans are seeking care for health challenges related to transitioning home and to civilian life. Congressionally mandated screening for mental health concerns in the Department of Defense (DoD), as well as screening efforts Veterans Affairs (VA) facilities, has been established with the goal of decreasing stigma and ensuring service members and veterans with depression and posttraumatic stress disorder (PTSD) receive needed treatment. Both the DoD and VA have also developed integrated behavioral health in primary-care based initiatives, which emphasize PTSD screening, treatment, and care coordination. This article discusses the rationale for population-level deployment-related mental health screening, recent changes to screening frequency, commonly used screening instruments such as the primary care PTSD screen (PC-PTSD), PTSD checklist (PCL), and Davidson Trauma Scale (DTS); as well as the strengths/limitations of each, and recommended cut-off scores based on expected PTSD prevalence.


Asunto(s)
Tamizaje Masivo/instrumentación , Personal Militar/psicología , Trastornos por Estrés Postraumático/diagnóstico , Veteranos/psicología , Prestación Integrada de Atención de Salud/organización & administración , Humanos , Tamizaje Masivo/organización & administración , Valor Predictivo de las Pruebas , Escalas de Valoración Psiquiátrica/normas , Sensibilidad y Especificidad , Encuestas y Cuestionarios/normas , Estados Unidos
11.
Bioprocess Biosyst Eng ; 37(10): 2067-72, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24728964

RESUMEN

Bacteriophage materials have the potential to revolutionize medicine, energy production and storage, agriculture, solar cells, optics and many other fields. To fulfill these needs, this study examined critical process parameters during phage propagation to increase phage production capability. A representative scale-down system was created in tube spin reactors to allow parallel experimentation with single- and multi-variable analysis. Temperature, harvest time, media composition, feed regime, bacteriophage, and bacteria concentration were analyzed in the scale-down system. Temperature, media composition, and feeding regimens were found to affect phage production more than other factors. Temperature affected bacterial growth and phage production inversely. Multi-variate analysis identified an optimal parameter space which provided a significant improvement over the base line method. This method should be useful in scaled production of bacteriophage for biotechnology.


Asunto(s)
Bacteriófago M13/metabolismo , Medios de Cultivo , Fermentación , Temperatura
12.
Nutrients ; 16(11)2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-38892520

RESUMEN

Serum-derived bovine immunoglobulin (SBI) prevents translocation and inflammation via direct binding of microbial components. Recently, SBI also displayed potential benefits through gut microbiome modulation. To confirm and expand upon these preliminary findings, SBI digestion and colonic fermentation were investigated using the clinically predictive ex vivo SIFR® technology (for 24 human adults) that was, for the first time, combined with host cells (epithelial/immune (Caco-2/THP-1) cells). SBI (human equivalent dose (HED) = 2 and 5 g/day) and the reference prebiotic inulin (IN; HED = 2 g/day) significantly promoted gut barrier integrity and did so more profoundly than a dietary protein (DP), especially upon LPS-induced inflammation. SBI also specifically lowered inflammatory markers (TNF-α and CXCL10). SBI and IN both enhanced SCFA (acetate/propionate/butyrate) via specific gut microbes, while SBI specifically stimulated valerate/bCFA and indole-3-propionic acid (health-promoting tryptophan metabolite). Finally, owing to the high-powered cohort (n = 24), treatment effects could be stratified based on initial microbiota composition: IN exclusively stimulated (acetate/non-gas producing) Bifidobacteriaceae for subjects classifying as Bacteroides/Firmicutes-enterotype donors, coinciding with high acetate/low gas production and thus likely better tolerability of IN. Altogether, this study strongly suggests gut microbiome modulation as a mechanism by which SBI promotes health. Moreover, the SIFR® technology was shown to be a powerful tool to stratify treatment responses and support future personalized nutrition approaches.


Asunto(s)
Microbioma Gastrointestinal , Inflamación , Humanos , Microbioma Gastrointestinal/efectos de los fármacos , Bovinos , Adulto , Animales , Masculino , Femenino , Células CACO-2 , Inmunoglobulinas , Colon/microbiología , Colon/metabolismo , Colon/efectos de los fármacos , Inulina/farmacología , Células THP-1 , Fermentación , Persona de Mediana Edad , Prebióticos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiología , Mucosa Intestinal/efectos de los fármacos , Ácidos Grasos Volátiles/metabolismo
13.
Am Fam Physician ; 88(12): 827-34, 2013 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-24364547

RESUMEN

Posttraumatic stress disorder (PTSD) occurs in an estimated 8% of men and 20% of women who are exposed to traumatic events. PTSD is a trauma- and stress-related disorder associated with significant psychosocial morbidity, substance abuse, and other negative physical health outcomes. The hallmarks of PTSD include exposure to a traumatic event; reexperiencing the event or intrusion symptoms; avoidance of people, places, or things that serve as a reminder of the trauma; negative mood and thoughts associated with the trauma; and chronic hyperarousal symptoms. Self-report questionnaires can assist clinicians in identifying anxiety problems associated with traumatic events. For patients who meet criteria for PTSD, trauma-focused psychotherapy and pharmacotherapy improve symptoms. Benzodiazepines and atypical antipsychotics are not recommended because studies have shown that adverse effects outweigh potential health benefits. Primary care physicians should monitor patients with PTSD for comorbid conditions such as substance abuse, mood disorders, and suicidality, and should refer patients to behavioral health specialists and support groups when appropriate.


Asunto(s)
Trastornos por Estrés Postraumático , Algoritmos , Terapia Combinada , Técnicas de Apoyo para la Decisión , Humanos , Psicoterapia , Psicotrópicos/uso terapéutico , Factores de Riesgo , Trastornos por Estrés Postraumático/diagnóstico , Trastornos por Estrés Postraumático/epidemiología , Trastornos por Estrés Postraumático/etiología , Trastornos por Estrés Postraumático/terapia , Encuestas y Cuestionarios , Estados Unidos/epidemiología
14.
Soc Sci Med ; 330: 116049, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37418990

RESUMEN

RATIONALE: Burnout is a personal and occupational phenomenon that has been associated with negative physical and psychological outcomes in medical staff. Additionally, there are implications for healthcare organizations, as those staff who are burned out are more likely to have lower productivity or leave the organization. As with the Covid-19 pandemic, future national emergencies and potentially large-scale conflicts will require similar and likely even larger scale responses from the U.S. Military Health System, thus it is important to understand burnout in this population so that the readiness of the staff and the military can remain at a high level. OBJECTIVE: This assessment was designed to examine levels of burnout among United States Military Health System (MHS) staff working at Army installations and the factors that influence the development of burnout. METHODS: Anonymous data was collected from 13,558 active-duty U.S. Soldiers and civilian MHS employees. Burnout was measured using the Copenhagen Burnout Inventory and the Mini-Z. RESULTS: Results showed nearly half of staff who responded (48%) reported being burned out, an increase since last measured in 2019 (31%). Factors related to increased burnout included concerns about work/life balance and workload, low job satisfaction and feeling disconnected from others. Burnout was associated with increases in adverse physical and behavioral health (BH) outcomes. CONCLUSIONS: Results indicate that burnout is a common problem across MHS Army staff and is related to significant adverse health consequences for the individual and reduced retention of staff for the organization. These findings highlight the need to address burnout through policies that standardize health care delivery policies and practices, providing support to leadership to promote a healthy workplace, and individual support to those who experience burnout.


Asunto(s)
Agotamiento Profesional , COVID-19 , Servicios de Salud Militares , Humanos , Estados Unidos/epidemiología , Pandemias , COVID-19/epidemiología , Agotamiento Profesional/epidemiología , Agotamiento Profesional/psicología , Atención a la Salud , Satisfacción en el Trabajo , Encuestas y Cuestionarios
15.
Microorganisms ; 11(3)2023 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-36985232

RESUMEN

Serum-derived bovine immunoglobulins (SBI) exert health benefits mediated by their ability to bind microbial components, thereby preventing translocation and subsequent inflammation. While in vivo studies have shown that a fraction of SBI also reaches the colon, little is known about the impact of SBI on the dense colonic microbiota that has great potential to impact human health. This study, therefore, investigated the impact of three bovine plasma protein fractions (SBI, bovine plasma (BP) and albumin-enriched bovine plasma (ABP)) on the gut microbiota of six human adults using the novel ex vivo SIFR® technology, recently demonstrated to generate predictive findings for clinical studies. When dosed at an equivalent of 5 g/day, all protein fractions significantly increased health-related metabolites-acetate, propionate, and butyrate. Upon simulating small intestinal absorption, SBI still markedly increased acetate and propionate, demonstrating that SBI is more resistant to small intestinal digestion and absorption compared to the other protein sources. Despite noticeable interindividual differences in microbiota composition among human adults, SBI consistently stimulated a narrow spectrum of gut microbes, which largely differed from the ones that are typically involved in carbohydrate fermentation. The SBI-fermenting consortium included B. vulgatus and L. edouardi (correlating with acetate and propionate) along with Dorea longicatena, Coprococcus comes and the butyrate-producing bacterium SS3/4 (correlating with butyrate). Overall, this study revealed that protein bovine fractions can contribute to health benefits by specifically modulating the human gut microbiota. While health benefits could follow from the production of SCFA, a broader range of protein-derived metabolites could also be produced. This study also confirms that the concept of prebiotics (substrates selectively utilized by host microorganisms conferring a health benefit) could go beyond the use of ingestible carbohydrates and extend to partially indigestible proteins.

16.
Lancet ; 378(9794): 915-24, 2011 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-21890056

RESUMEN

BACKGROUND: Breakdowns in the ethical conduct of soldiers towards non-combatants on the battlefield are of grave concern in war. Evidence-based training approaches to prevent unethical conduct are scarce. We assessed the effectiveness of battlefield-ethics training and factors associated with unethical battlefield conduct. METHODS: The training package, based on movie vignettes and leader-led discussions, was administered 7 to 8 months into a 15-month high-intensity combat deployment in Iraq, between Dec 11, 2007, and Jan 30, 2008. Soldiers from an infantry brigade combat team (total population about 3500) were randomly selected, on the basis of company and the last four digits of each soldier's social security number, and invited to complete an anonymous survey 3 months after completion of the training. Reports of unethical behaviour and attitudes in this sample were compared with a randomly selected pre-training sample from the same brigade. The response patterns for ethical behaviour and reporting of ethical violations were analysed with chi-square analyses. We developed two logistic regression models using self-reported unethical behaviours as dependent variables. Factors associated with unethical conduct, including combat experiences and post-traumatic stress disorder (PTSD), were assessed with validated scales. FINDINGS: Of 500 randomly selected soldiers 421 agreed to participate in the anonymous post-training survey. A total of 397 soldiers of the same brigade completed the pre-training survey. Training was associated with significantly lower rates of unethical conduct of soldiers and greater willingness to report and address misconduct than in those before training. For example, reports of unnecessary damage or destruction of private property decreased from 13·6% (54 of 397; 95% CI 10·2-17·0) before training to 5·0% (21 of 421; 2·9-7·1) after training (percent difference -63·2%; p<0·0001), and willingness to report a unit member for mistreatment of a non-combatant increased from 36·0% (143 of 397; 31·3-40·7) to 58·9% (248 of 421; 54·2-63·6; percent difference 63·6; p<0·0001). Nearly all participants (410 [97%]) reported that training made it clear how to respond towards non-combatants. Combat frequency and intensity was the strongest predictor of unethical behaviour; PTSD was not a significant predictor of unethical behaviour after controlling for combat experiences. INTERPRETATION: Leader-led battlefield ethics training positively influenced soldiers' understanding of how to interact with and treat non-combatants, and reduced reports of ethical misconduct. Unethical battlefield conduct was associated with high-intensity combat but not with PTSD. FUNDING: None.


Asunto(s)
Códigos de Ética , Guerra de Irak 2003-2011 , Personal Militar/educación , Ciencia Militar/ética , Guerra/ética , Actitud , Conducta , Recolección de Datos , Humanos , Estados Unidos
17.
Org Biomol Chem ; 10(11): 2189-200, 2012 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-22307888

RESUMEN

Chiral amines are key components in numerous bioactive molecules. The development of efficient and economical ways to access molecules containing this functional group still remains a challenge at the forefront of synthetic chemistry. Of the methods that do exist, the trichlorosilane mediated organocatalytic reduction of ketimines offers significant potential as an alternative strategy. In this perspective, we wish to highlight the progress made in the past decade in this field and offer a direct quantitative comparison to transition-metal mediated process.

18.
Environ Sci Technol ; 46(14): 7790-8, 2012 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-22697906

RESUMEN

Interspecies uncertainty factors in ecological risk assessment provide conservative estimates of risk where limited or no toxicity data is available. We quantitatively examined the validity of interspecies uncertainty factors by comparing the responses of zebrafish (Danio rerio) and fathead minnow (Pimephales promelas) to the energetic compound 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), a known neurotoxicant. Relative toxicity was measured through transcriptional, morphological, and behavioral end points in zebrafish and fathead minnow fry exposed for 96 h to RDX concentrations ranging from 0.9 to 27.7 mg/L. Spinal deformities and lethality occurred at 1.8 and 3.5 mg/L RDX respectively for fathead minnow and at 13.8 and 27.7 mg/L for zebrafish, indicating that zebrafish have an 8-fold greater tolerance for RDX than fathead minnow fry. The number and magnitude of differentially expressed transcripts increased with increasing RDX concentration for both species. Differentially expressed genes were enriched in functions related to neurological disease, oxidative-stress, acute-phase response, vitamin/mineral metabolism and skeletal/muscular disorders. Decreased expression of collagen-coding transcripts were associated with spinal deformity and likely involved in sensitivity to RDX. Our work provides a mechanistic explanation for species-specific sensitivity to RDX where zebrafish responded at lower concentrations with greater numbers of functions related to RDX tolerance than fathead minnow. While the 10-fold interspecies uncertainty factor does provide a reasonable cross-species estimate of toxicity in the present study, the observation that the responses between ZF and FHM are markedly different does initiate a call for concern regarding establishment of broad ecotoxicological conclusions based on model species such as zebrafish.


Asunto(s)
Cyprinidae/metabolismo , Ecotoxicología/métodos , Biología de Sistemas/métodos , Triazinas/toxicidad , Pez Cebra/metabolismo , Animales , Conducta Animal/efectos de los fármacos , Bioensayo , Colágeno/genética , Colágeno/metabolismo , Cyprinidae/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Programas Informáticos , Especificidad de la Especie , Columna Vertebral/anomalías , Columna Vertebral/efectos de los fármacos , Análisis de Supervivencia , Natación/fisiología , Pez Cebra/genética
19.
Acad Psychiatry ; 35(3): 175-83, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21602439

RESUMEN

OBJECTIVE: The authors assess the perspectives of psychiatry residents about the goals of receiving education in professionalism and ethics, how topics should be taught, and on what ethical principles the curriculum should be based. METHOD: A written survey was sent to psychiatry residents (N=249) at seven U.S. residency programs in Spring 2005. The survey was based on an instrument originally developed at the University of New Mexico, consisting of 149 questions in 10 content domains, with 6 questions regarding ethics experiences during training and 5 demographic questions. RESULTS: A total of 151 psychiatry residents (61%) returned usable responses to our survey. Residents reported receiving a moderate amount of ethics training during medical school (mean: 5.20; scale: 1: None to 9: Very Much) and some ethics training during residency (mean: 4.60). Residents endorsed moderate to moderately-strong agreement with all 11 goals of medical education in professionalism and ethics (means: 5.29 to 7.49; scale: 1: Strongly Disagree to 9: Strongly Agree). Respondents were more likely to endorse the value of clinically- and expert-oriented learning methods over web-based educational approaches. CONCLUSION: U.S. psychiatry residents endorse a range of goals for education in professionalism and ethics. At the same time, they prefer that these topics be taught in clinically relevant ways and through expert instruction. The value of web-based approaches warrants further investigation.


Asunto(s)
Internado y Residencia , Psiquiatría/educación , Adulto , Curriculum/normas , Recolección de Datos , Femenino , Objetivos , Humanos , Masculino , Psiquiatría/ética , Psiquiatría/normas , Facultades de Medicina/normas , Estados Unidos
20.
Appl Environ Microbiol ; 76(1): 338-46, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19915043

RESUMEN

A gene encoding a glycoside hydrolase family 44 (GH44) protein from Clostridium acetobutylicum ATCC 824 was synthesized and transformed into Escherichia coli. The previously uncharacterized protein was expressed with a C-terminal His tag and purified by nickel-nitrilotriacetic acid affinity chromatography. Crystallization and X-ray diffraction to a 2.2-A resolution revealed a triose phosphate isomerase (TIM) barrel-like structure with additional Greek key and beta-sandwich folds, similar to other GH44 crystal structures. The enzyme hydrolyzes cellotetraose and larger cellooligosaccharides, yielding an unbalanced product distribution, including some glucose. It attacks carboxymethylcellulose and xylan at approximately the same rates. Its activity on carboxymethylcellulose is much higher than that of the isolated C. acetobutylicum cellulosome. It also extensively converts lichenan to oligosaccharides of intermediate size and attacks Avicel to a limited extent. The enzyme has an optimal temperature in a 10-min assay of 55 degrees C and an optimal pH of 5.0.


Asunto(s)
Celulasa/química , Celulasa/metabolismo , Clostridium acetobutylicum/enzimología , Carboximetilcelulosa de Sodio/metabolismo , Celulasa/genética , Celulasa/aislamiento & purificación , Celulosa/análogos & derivados , Celulosa/metabolismo , Clostridium acetobutylicum/genética , Cristalización , Cristalografía por Rayos X , Estabilidad de Enzimas , Escherichia coli/genética , Expresión Génica , Glucanos/metabolismo , Glucosa/metabolismo , Concentración de Iones de Hidrógeno , Cinética , Modelos Moleculares , Oligosacáridos/metabolismo , Filogenia , Estructura Terciaria de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , Homología de Secuencia de Aminoácido , Especificidad por Sustrato , Temperatura , Tetrosas/metabolismo , Transformación Genética , Xilanos/metabolismo
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