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1.
Poult Sci ; 100(11): 101467, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34624775

RESUMO

The effect of sodium chloride (NaCl) and NaCl+sodium hydrogen carbonate (NaHCO3) and supplemental phytase (0, 500, 1,000, and 2,000 FTU/kg) on performance, nutrient digestibility and utilization, and digesta pH of male broiler chickens were investigated in a 2 × 4+1 factorial arrangement of treatments in a completely randomized design with 6 replicate cages of 8 birds per replicate. Data were analyzed as a 2 × 4 factorial with contrast between the positive control and the diets containing 0 FTU phytase. Phytase supplementation linearly improved (P < 0.05) average body weigh gain (BWG) and feed intake (d 0-14 and 0-21). Apparent jejunal dry matter (DM) digestibility and digestible energy in birds fed diets containing only NaCl increased (linear and quadratic; P < 0.05) with phytase supplementation whereas quadratic (P < 0.05) effect was observed in birds fed diets containing a combination of NaCl and NaHCO3. Phytase supplementation improved (linear and quadratic; P < 0.05) apparent ileal nitrogen and P digestibility. Apparent utilization of DM, nitrogen, energy, and metabolizable energy increased (linear; P < 0.05) with increasing level of phytase supplementation. Apparent P utilization increased (linear and quadratic; P < 0.05) for both sodium sources but calcium utilization only increased (linear; P < 0.05) with the combination of NaCl and NaHCO3. Bone breaking strength (linear and quadratic) and bone ash (linear) increased (P < 0.05) with phytase supplementation. The combination of NaCl and NaHCO3 resulted in lower (P < 0.05) pH of digesta in the proximal ileum whereas the pH of the digesta in the distal ileum (linear) and the average pH of ileal contents (linear and quadratic) increased (P < 0.05) with phytase supplementation. Results from this study showed that birds' performance and utilization of nutrients and energy by broilers in the presence of phytase was, in general, not influenced by the source of sodium in the diet. Data from this study showed that NaHCO3 can replace a portion of NaCl in the diet of broilers supplemented with phytase without any significant negative effect on performance and that the 2,000 FTU phytase level resulted in better BWG and feed intake as well nutrient and energy utilization.


Assuntos
6-Fitase , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Galinhas , Dieta/veterinária , Suplementos Nutricionais , Digestão , Concentração de Íons de Hidrogênio , Masculino , Nutrientes , Sódio
2.
J Neurosurg ; : 1-8, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29957115

RESUMO

OBJECTIVEAmid the public health controversy surrounding American football, a helmet that can reduce linear and rotational acceleration has the potential to decrease forces transmitted to the brain. The authors hypothesized that a football helmet with an outer shell would reduce both linear and rotational acceleration. The authors' objectives were to 1) determine an optimal material for a shock-absorbing outer shell and 2) examine the ability of an outer shell to reduce linear and/or rotational acceleration.METHODSA laboratory-based investigation was undertaken using an extra-large Riddell Revolution football helmet. Two materials (Dow Corning Dilatant Compound and Sorbothane) were selected for their non-Newtonian properties (changes in viscosity with shear stress) to develop an outer shell. External pads were attached securely to the helmet at 3 locations: the front boss, the side, and the back. The helmet was impacted 5 times per location at 6 m/sec with pneumatic ram testing. Two-sample t-tests were used to evaluate linear/rotational acceleration differences between a helmet with and a helmet without the outer shell.RESULTSSorbothane was superior to the Dow Corning compound in force reduction and recovered from impact without permanent deformation. Of 5 different grades, 70-duro (a unit of hardness measured with a durometer) Sorbothane was found to have the greatest energy dissipation and stiffness, and it was chosen as the optimal outer-shell material. The helmet prototype with the outer shell reduced linear acceleration by 5.8% (from 75.4g to 71.1g; p < 0.001) and 10.8% (from 89.5g to 79.8g; p = 0.033) at the side and front boss locations, respectively, and reduced rotational acceleration by 49.8% (from 9312.8 rad/sec2 to 4671.7 rad/sed2; p < 0.001) at the front boss location.CONCLUSIONSSorbothane (70 duro) was chosen as the optimal outer-shell material. In the outer-shell prototype helmet, the results demonstrated a 5%-10% reduction in linear acceleration at the side and front boss locations, and a 50% reduction in rotational acceleration at the front boss location. Given the paucity of publicly reported helmet-design literature and the importance of rotational acceleration in head injuries, the substantial reduction seen in rotational acceleration with this outer-shell prototype holds the potential for future helmet-design improvements.

3.
Neurology ; 91(1): e67-e77, 2018 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-29848786

RESUMO

OBJECTIVE: While epilepsy studies rarely examine brainstem, we sought to examine the hypothesis that temporal lobe epilepsy (TLE) leads to subcortical arousal center dysfunction, contributing to neocortical connectivity and neurocognitive disturbances. METHODS: In this case-control study of 26 adult patients with TLE and 26 controls, we used MRI to measure structural and functional connectivity of the cuneiform/subcuneiform nuclei (CSC), pedunculopontine nucleus, and ventral tegmental area. Ascending reticular activating system connectivity patterns were related to neuropsychological and disease measures. RESULTS: Compared to controls, patients with TLE demonstrated reductions in ascending reticular activating system structural and functional connectivity, most prominently to neocortical regions (p < 0.05, unpaired t tests, corrected). While reduced CSC structural connectivity was related to impaired performance IQ and visuospatial memory, diminished CSC functional connectivity was associated with impaired verbal IQ and language abilities (p < 0.05, Spearman ρ, t tests). Finally, CSC structural connectivity decreases were quantitatively associated with consciousness-impairing seizure frequency (p < 0.05, Spearman ρ) and the presence of generalized seizures (p < 0.05, unpaired t test), suggesting a relationship to disease severity. CONCLUSIONS: Connectivity perturbations in brainstem arousal centers are present in TLE and may contribute to neurocognitive problems. These studies demonstrate the underappreciated role of brainstem networks in epilepsy and may lead to novel neuromodulation targets to treat or prevent deleterious brain network effects of seizures in TLE.


Assuntos
Tronco Encefálico/diagnóstico por imagem , Tronco Encefálico/fisiopatologia , Epilepsia/diagnóstico por imagem , Rede Nervosa/diagnóstico por imagem , Adulto , Estudos de Casos e Controles , Transtornos Cognitivos/diagnóstico por imagem , Transtornos Cognitivos/etiologia , Epilepsia/complicações , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Rede Nervosa/fisiopatologia , Testes Neuropsicológicos , Oxigênio/sangue , Estudos Retrospectivos
4.
Brain Imaging Behav ; 12(5): 1332-1345, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29188492

RESUMO

There are concerns about the effects of subconcussive head impacts in sport, but the effects of subconcussion on brain connectivity are not well understood. We hypothesized that college football players experience changes in brain functional connectivity not found in athletes competing in lower impact sports or healthy controls. These changes may be spatially heterogeneous across participants, requiring analysis methods that go beyond mass-univariate approaches commonly used in functional MRI (fMRI). To test this hypothesis, we analyzed resting-state fMRI data from college football (n = 15), soccer (n = 12), and lacrosse players (n = 16), and controls (n = 29) collected at preseason and postseason time points. Regional homogeneity (ReHo) and degree centrality (DC) were calculated as measures of local and long-range functional connectivity, respectively. Standard voxel-wise analysis and paired support vector machine (SVM) classification studied subconcussion's effects on local and global functional connectivity. Voxel-wise analyses yielded minimal findings, but SVM classification had high accuracy for college football's ReHo (87%, p = 0.009) and no other group. The findings suggest subconcussion results in spatially heterogeneous changes in local functional connectivity that may only be detectible with multivariate analyses. To determine if voxel-wise and SVM analyses had similar spatial patterns, region-average t-statistic and SVM weight values were compared using a measure of ranking distance. T-statistic and SVM weight rankings exhibited significantly low ranking distance values for all groups and metrics, demonstrating that the analyses converged on a similar underlying effect. Overall, this research suggests that subconcussion in football may produce local functional connectivity changes similar to concussion.


Assuntos
Concussão Encefálica/diagnóstico por imagem , Concussão Encefálica/fisiopatologia , Mapeamento Encefálico/métodos , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Imageamento por Ressonância Magnética , Atletas , Traumatismos em Atletas/diagnóstico por imagem , Traumatismos em Atletas/fisiopatologia , Futebol Americano/lesões , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Análise Multivariada , Esportes com Raquete/lesões , Descanso , Futebol/lesões , Máquina de Vetores de Suporte , Universidades , Adulto Jovem
5.
J Anim Sci ; 95(9): 3905-3913, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28991992

RESUMO

Selection lines of sheep with low and high CH yield (g/kg DMI; CH/DMI) are being developed on the basis of feeding pelleted alfalfa hay at 2.0 times maintenance ME requirements in respiration chambers, but their divergence under predominant grazing conditions, as in New Zealand, is not known. The objectives of this study were to determine CH emissions and rumen fermentation characteristics in sheep from low and high CH/DMI selection lines while grazing pasture. Two grazing experiments were conducted with 42 selection line ewes in March 2013 (Exp. 1) and 98 selection line progeny ewe hoggets in October/November 2014 (Exp. 2), with CH emissions estimated by the SF tracer technique and DMI estimated by titanium oxide in combination with natural long-chain -alkanes. Total daily CH production (g/d) was similar between high and low CH/DMI selection line sheep in Exp. 1 and lower for low CH/DMI progeny compared with high CH/DMI progeny in Exp. 2 ( < 0.05). The CH/DMI tended to be 20% lower for low CH/DMI line sheep compared with high CH/DMI selection line sheep in Exp. 1 ( < 0.10) and was 15% lower for the low CH/DMI line in Exp. 2 ( < 0.01). Total VFA concentration and concentrations (m) of acetate, butyrate, and isobutyrate plus isovalerate were lower ( < 0.05) for low CH/DMI line sheep compared with high CH/DMI selection line sheep in both experiments. The current study indicates that differences in CH/DMI and VFA concentrations in selection line sheep, previously established on alfalfa pellets, are also present to a similar magnitude when grazing pasture.


Assuntos
Ração Animal/análise , Medicago sativa , Metano/metabolismo , Ovinos/fisiologia , Agricultura/métodos , Animais , Dieta/veterinária , Feminino , Fermentação , Nova Zelândia , Distribuição Aleatória , Rúmen/metabolismo , Seleção Genética
6.
Orthop J Sports Med ; 5(4): 2325967117701708, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28491885

RESUMO

BACKGROUND: The effects of head impact in sports are of growing interest for clinicians, scientists, and athletes. Soccer is the most popular sport worldwide, but the burden of head impact in collegiate soccer is still unknown. PURPOSE: To quantify head impact associated with practicing and playing collegiate soccer using wearable accelerometers. STUDY DESIGN: Descriptive epidemiological study. METHODS: Mastoid patch accelerometers were used to quantify head impact in soccer, examining differences in head impact as a function of sex and event type (practice vs game). Seven female and 14 male collegiate soccer players wore mastoid patch accelerometers that measured head impacts during team events. Data were summarized for each athletic exposure, and statistical analyses evaluated the mean number of impacts, mean peak linear acceleration, mean peak rotational acceleration, and cumulative linear and rotational acceleration, each grouped by sex and event type. RESULTS: There were no differences in the frequency or severity of head impacts between men's and women's soccer practices. For men's soccer, games resulted in 285% more head impacts than practices, but there were no event-type differences in mean impact severity. Men's soccer games resulted in more head impacts than practices across nearly all measured impact severities, which also resulted in men's soccer games producing a greater cumulative impact burden. CONCLUSION: Similar to other sports, men's soccer games have a greater impact burden when compared with practices, and this effect is driven by the quantity rather than severity of head impacts. In contrast, there were no differences in the quantity or severity of head impacts in men's and women's soccer practices. These data could prompt discussions of practical concern to collegiate soccer, such as understanding sex differences in head impact and whether games disproportionately contribute to an athlete's head impact burden.

7.
Oncogene ; 36(28): 4001-4013, 2017 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-28288136

RESUMO

Increasing evidence supports the idea that cancer cell plasticity promotes metastasis and tumor recurrence, resulting in patient mortality. While it is clear that the tumor microenvironment (TME) contributes to cancer cell plasticity, the specific TME factors most actively controlling plasticity remain largely unknown. Here, we performed a screen to identify TME cytokines and growth factors that promote epithelial-mesenchymal plasticity, and acquisition of cancer stem cell (CSC) properties. Of 28 TME cytokines and growth factors tested, we identified Oncostatin M (OSM) as the most potent inducer of mesenchymal/CSC properties. OSM-induced plasticity was Signal Transducer and Activator of Transcription 3 (STAT3)-dependent, and also required a novel intersection with transforming growth factor-ß (TGF-ß)/SMAD signaling. OSM/STAT3 activation promoted SMAD3 nuclear accumulation, DNA binding and induced SMAD3-dependent transcriptional activity. Suppression of TGF-ß receptor activity or ablation of SMAD3 or SMAD4, but not SMAD2, strongly suppressed OSM/STAT3-mediated plasticity. Moreover, removal of OSM or inhibition of STAT3 or SMAD3 resulted in a marked reversion to a non-invasive, epithelial phenotype. We propose that targeted blockade of the STAT3/SMAD3 axis in tumor cells may represent a novel therapeutic approach to prevent the plasticity required for metastatic progression and tumor recurrence.


Assuntos
Plasticidade Celular/genética , Neoplasias/patologia , Oncostatina M/fisiologia , Fator de Transcrição STAT3/metabolismo , Proteína Smad3/metabolismo , Linhagem Celular Tumoral , Plasticidade Celular/efeitos dos fármacos , Células Cultivadas , Progressão da Doença , Transição Epitelial-Mesenquimal/genética , Humanos , Metástase Neoplásica , Neoplasias/genética , Oncostatina M/genética , Oncostatina M/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética
8.
J Neurotrauma ; 34(1): 38-49, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-27541183

RESUMO

As concerns about head impact in American football have grown, similar concerns have started to extend to other sports thought to experience less head impact, such as soccer and lacrosse. However, the amount of head impact experienced in soccer and lacrosse is relatively unknown, particularly compared with the substantial amount of data from football. This pilot study quantifies and compares head impact from four different types of sports teams: college football, high school football, college soccer, and college lacrosse. During the 2013 and 2014 seasons, 61 players wore mastoid patch accelerometers to quantify head impact during official athletic events (i.e., practices and games). In both practices and games, college football players experienced the most or second-most impacts per athletic event, highest average peak resultant linear and rotational acceleration per impact, and highest cumulative linear and rotational acceleration per athletic event. For average peak resultant linear and rotational acceleration per individual impact, college football was followed by high school football, then college lacrosse, and then college soccer, with similar trends in both practices and games. In the four teams under study, college football players experienced a categorically higher burden of head impact. However, for cumulative impact burden, the high school football cohort was not significantly different from the college soccer cohort. The results suggest that head impact in sport substantially varies by both the type of sport (football vs. soccer vs. lacrosse) and level of play (college vs. high school).


Assuntos
Acelerometria/instrumentação , Concussão Encefálica/fisiopatologia , Futebol Americano/lesões , Dispositivos de Proteção da Cabeça/tendências , Esportes com Raquete/lesões , Futebol/lesões , Acelerometria/métodos , Adolescente , Atletas , Fenômenos Biomecânicos/fisiologia , Concussão Encefálica/diagnóstico , Estudos de Coortes , Humanos , Projetos Piloto , Instituições Acadêmicas/tendências , Universidades/tendências , Adulto Jovem
9.
Am J Sports Med ; 44(11): 2947-2956, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27281278

RESUMO

BACKGROUND: Concussion and repetitive head impact in sports has increased interest and concern for clinicians, scientists, and athletes. Lacrosse is the fastest growing sport in the United States, but the burden of head impact in lacrosse is unknown. PURPOSE: The goal of this pilot study was to quantify head impact associated with practicing and playing collegiate lacrosse while subjects were fitted with wearable accelerometers. STUDY DESIGN: Descriptive epidemiology study. METHODS: In a single year, a collegiate cohort of 14 women's and 15 men's lacrosse players wore mastoid-patch accelerometers to measure the frequency and severity of head impacts during official practices and games. Average impact severity, mean number of impacts, and cumulative acceleration were evaluated, stratified by sport and event type. RESULTS: Men's and women's collegiate lacrosse players did not significantly differ in the number of head impacts received during games (11.5 for men vs 9.2 for women) or practices (3.1 vs 3.1). Men's lacrosse players had significantly higher average head acceleration per impact during games compared with women (21.1g vs 14.7g) but not during practices (21.3g vs 18.1g). For both men and women, more impacts occurred during games than during practices (men, 11.5 vs 3.1; women, 9.2 vs 3.1), but impact severity did not significantly differ between events for either sport (men, 21.1g vs 21.3g; women, 14.7g vs 18.1g). CONCLUSION: The study data suggest a higher impact burden during games compared with practices, but this effect is driven by the quantity rather than severity of impacts. In contrast, sex-based effects in impact burden are driven by average impact severity rather than quantity. Data collected from larger multisite trials and/or different age groups could be used to inform ongoing debates, including headgear and practice regulations, that might appreciably affect the burden of head impacts in lacrosse. CLINICAL RELEVANCE: While most head impacts do not result in a clinical diagnosis of concussion, evidence indicates that subconcussive head impacts may increase susceptibility to concussion and contribute to long-term neurodegeneration.


Assuntos
Acelerometria/métodos , Concussão Encefálica/epidemiologia , Esportes com Raquete/lesões , Acelerometria/instrumentação , Concussão Encefálica/etiologia , Feminino , Humanos , Masculino , Projetos Piloto , Estados Unidos/epidemiologia , Adulto Jovem
10.
J Neurosurg ; 124(2): 501-10, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26238972

RESUMO

UNLABELLED: OBJECT IVE: This study directly compares the number and severity of subconcussive head impacts sustained during helmet-only practices, shell practices, full-pad practices, and competitive games in a National Collegiate Athletic Association (NCAA) Division I-A football team. The goal of the study was to determine whether subconcussive head impact in collegiate athletes varies with practice type, which is currently unregulated by the NCAA. METHODS: Over an entire season, a cohort of 20 collegiate football players wore impact-sensing mastoid patches that measured the linear and rotational acceleration of all head impacts during a total of 890 athletic exposures. Data were analyzed to compare the number of head impacts, head impact burden, and average impact severity during helmet-only, shell, and full-pad practices, and games. RESULTS: Helmet-only, shell, and full-pad practices and games all significantly differed from each other (p ≤ 0.05) in the mean number of impacts for each event, with the number of impacts being greatest for games, then full-pad practices, then shell practices, and then helmet-only practices. The cumulative distributions for both linear and rotational acceleration differed between all event types (p < 0.01), with the acceleration distribution being similarly greatest for games, then full-pad practices, then shell practices, and then helmet-only practices. For both linear and rotational acceleration, helmet-only practices had a lower average impact severity when compared with other event types (p < 0.001). However, the average impact severity did not differ between any comparisons of shell and full-pad practices, and games. CONCLUSIONS: Helmet-only, shell, and full-pad practices, and games result in distinct head impact profiles per event, with each succeeding event type receiving more impacts than the one before. Both the number of head impacts and cumulative impact burden during practice are categorically less than in games. In practice events, the number and cumulative burden of head impacts per event increases with the amount of equipment worn. The average severity of individual impacts is relatively consistent across event types, with the exception of helmet-only practices. The number of hits experienced during each event type is the main driver of event type differences in impact burden per athletic exposure, rather than the average severity of impacts that occur during the event. These findings suggest that regulation of practice equipment could be a fair and effective way to substantially reduce subconcussive head impact in thousands of collegiate football players.


Assuntos
Traumatismos Craniocerebrais/epidemiologia , Futebol Americano/lesões , Aceleração , Fenômenos Biomecânicos , Técnicas Biossensoriais , Carga Corporal (Radioterapia) , Concussão Encefálica , Lesões Encefálicas/epidemiologia , Estudos de Coortes , Futebol Americano/estatística & dados numéricos , Dispositivos de Proteção da Cabeça , Humanos , Escala de Gravidade do Ferimento , Estimativa de Kaplan-Meier , Masculino , Rotação , Adulto Jovem
11.
Oncogene ; 33(25): 3298-306, 2014 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-23912460

RESUMO

Despite the progress made in targeted anticancer therapies in recent years, challenges remain. The identification of new potential targets will ensure that the arsenal of cancer therapies continues to expand. FAM83B was recently discovered in a forward genetic screen for novel oncogenes that drive human mammary epithelial cell (HMEC) transformation. We report here that elevated FAM83B expression increases Phospholipase D (PLD) activity, and that suppression of PLD1 activity prevents FAM83B-mediated transformation. The increased PLD activity is engaged by hyperactivation of epidermal growth factor receptor (EGFR), which is regulated by an interaction involving FAM83B and EGFR. Preventing the FAM83B/EGFR interaction by site-directed mutation of lysine 230 of FAM83B suppressed PLD activity and MAPK signaling. Furthermore, ablation of FAM83B expression from breast cancer cells inhibited EGFR phosphorylation and suppressed cell proliferation. We propose that understanding the mechanism of FAM83B-mediated transformation will provide a foundation for future therapies aimed at targeting its function as an intermediary in EGFR, MAPK and mTOR activation.


Assuntos
Receptores ErbB/metabolismo , Proteínas de Neoplasias/metabolismo , Oncogenes/genética , Fosfolipase D/metabolismo , Neoplasias da Mama/enzimologia , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Processos de Crescimento Celular/fisiologia , Linhagem Celular , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Ativação Enzimática , Células Epiteliais/metabolismo , Receptores ErbB/genética , Feminino , Humanos , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas de Neoplasias/genética , Fosfolipase D/genética , Fosforilação , Transdução de Sinais
12.
J Hazard Mater ; 82(1): 65-75, 2001 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-11165062

RESUMO

Solvent sublation, an adsorptive bubble separation process, was carried out on a pilot scale to separate dilute concentrations (30-100ppmw) of naphthalene from a process water stream at a temperature of 140 degrees F. The test was conducted at the Borden Chemicals and Plastics (BCP) acetylene plant site located in Geismar, Louisiana. A carbon steel column of 6" i.d. and 17' high was constructed. White mineral oil supplied by Texaco Inc., was used as the organic solvent for solvent sublation. A special annular shear sparger was used for nitrogen gas sparging into the vessel. The process was conducted in two-phase continuous and three-phase continuous modes. The naphthalene recovery from the process water was independent of the oil flow rate, but depended on the nitrogen-to-water flow rate ratio. The release of naphthalene to the overhead gas space during the solvent sublation process was substantially less than that during conventional gas stripping. The improved performance of solvent sublation over both conventional gas stripping and solvent extraction operations was apparent.


Assuntos
Naftalenos/química , Solventes/química , Poluição da Água/prevenção & controle , Adsorção , Óleo Mineral/química , Projetos Piloto , Temperatura
14.
Arch Biochem Biophys ; 261(2): 394-404, 1988 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2895607

RESUMO

Unidirectional transport of poly(A)-containing mRNA [poly(A)+ mRNA] through the nuclear envelope pore complex is thought to be an energy (ATP or GTP)-dependent process which involves a nuclear envelope nucleoside triphosphatase (NTPase). In the intact envelope, this enzyme is regulatable by poly(A) binding and by poly(A)-dependent phosphorylation/dephosphorylation of other components of the mRNA translocation system, which are as yet unidentified. Monoclonal antibodies (mAbs) were elicited against the poly(A) binding nuclear envelope fraction isolated from rat liver. The mAbs were screened for their modulatory effects on mRNA transport in vitro. One stable clone decreased the efflux of rapidly labeled RNA and of one specific mRNA (ovalbumin) from isolated nuclei. It increased the binding of poly(A) to the envelope and increased the maximal catalytic rate of the NTPase, but it did not alter the apparent Km of the enzyme or the extent of its stimulation by poly(A). The nuclear envelope-associated protein kinase that down-regulates the NTPase was inhibited by the antibody, while other protein kinases were not affected. Because both the NTPase and mRNA efflux were inhibited by the tumor promoter, 12-O-tetradecanoylphorbol 13-acetate, the sensitive kinase is probably protein kinase C. Protein kinase C was found to be associated with the isolated nuclear envelope. The antibody reacted with both a Mr 83,000 and a Mr 65,000 nuclear envelope polypeptide from rat liver and other tissues. By immunofluorescence microscopy in CV-1 cells, the antibody localized to the nuclear envelope and, in addition, to cytoplasmic filaments which show some superposition with the microfilament network.


Assuntos
Citoesqueleto/metabolismo , Membrana Nuclear/metabolismo , Ésteres de Forbol/farmacologia , RNA Mensageiro/metabolismo , Trifosfato de Adenosina/farmacologia , Animais , Anticorpos Monoclonais , Transporte Biológico , Galinhas , Citoesqueleto/imunologia , Guanosina Trifosfato/farmacologia , Técnicas In Vitro , Cinética , Camundongos , Camundongos Endogâmicos BALB C , Membrana Nuclear/enzimologia , Nucleosídeo-Trifosfatase , Monoéster Fosfórico Hidrolases/antagonistas & inibidores , Monoéster Fosfórico Hidrolases/metabolismo , Fosforilação , Poli A/metabolismo
18.
Crit Care Med ; 11(2): 79-82, 1983 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-6822084

RESUMO

Determining adequacy of mechanical ventilation is as important during CPR as in a more stable situation (such as, a patient on a ventilator in an ICU). Yet, such assessment during CPR usually only means listening for breath sounds, checking chest excursion, and blood gases. Exhaled tidal volume (VT) was measured on 45 intubated adult patients during resuscitation using a Wright's spirometer attached to a T-valve above the endotracheal tube. Ten patients had aspiration prior to intubation; 15 received advanced cardiac life support in the field, including esophageal airway insertion. CPR was performed in all cases with a mechanical compression device (Thumper). The pressure ventilator on this device was calibrated (peak inspiratory pressure, VT vs compliance) using a Dixie Test Lung, allowing indirect assessment of pulmonary compliance during CPR. Our findings suggest that lung compliance is markedly reduced within a short time after cardiac arrest. Fifty-five % of patients in this series could not be adequately oxygenated (PaO2 less than 50 torr) despite an FIO2 of 0.8 and adequate ventilation. Due to the reduced cardiac output during CPR causing venoarterial shunting, it is speculated that pulmonary edema is the most plausible explanation for this observation.


Assuntos
Monitorização Fisiológica/instrumentação , Respiração Artificial , Ressuscitação/métodos , Idoso , Feminino , Parada Cardíaca/terapia , Humanos , Complacência Pulmonar , Masculino , Pessoa de Meia-Idade , Edema Pulmonar/etiologia
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