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1.
Br J Anaesth ; 122(6): 751-759, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30916034

RESUMO

BACKGROUND: Gestational changes in coagulation factor concentrations include elevations in fibrinogen, Factor VIII, and von Willebrand factor (vWF). We hypothesised that blood samples from term pregnant (TP) subjects are less prone to coagulation disturbances from haemodilution compared with those from non-pregnant (NP) females. METHODS: Blood samples were collected from 15 NP and 15 TP subjects. In vitro haemodilution with normal saline was assessed by modified Clauss fibrinogen assay, factor activity, flow-chamber assay, and thromboelastometry. The impact of human fibrinogen concentrate (hFC), cryoprecipitate, and vWF/Factor VIII (FVIII) concentrate replacement in diluted TP and NP blood was compared. Thrombin generation and activated protein C sensitivity were assessed. RESULTS: TP blood contained twice the concentrations of fibrinogen, FVIII, and vWF relative to NP blood (P<0.0001). Platelet thrombus formation (PTF) under flow was reduced by 99.2% and 69.2% in diluted NP and TP blood, respectively. Platelet thrombus formation was partially restored by adding vWF/FVIII, but not hFC or cryoprecipitate. Fibrin clot firmness approached the threshold of 10 mm in diluted NP blood, and clot firmness was effectively restored by hFC, but not by vWF/FVIII. In the presence of thrombomodulin, peak thrombin generation was decreased by 86.7% in NP plasma, but by 31.8% in TP plasma (P<0.0001 vs NP plasma), indicating reduced activated protein C sensitivity in TP plasma. Both elevated FVIII and haemodilution contributed to activated protein C insensitivity. CONCLUSIONS: Our in vitro model showed relative resistance of TP blood to dilutional coagulation changes with respect to platelet adhesion, fibrin polymerisation, and thrombin generation. Careful therapeutic monitoring for different pro-haemostatic agents in pregnant women is warranted.


Assuntos
Transtornos da Coagulação Sanguínea/sangue , Fatores de Coagulação Sanguínea/análise , Hemodiluição/efeitos adversos , Complicações Hematológicas na Gravidez/sangue , Adulto , Transtornos da Coagulação Sanguínea/etiologia , Coleta de Amostras Sanguíneas/métodos , Monitoramento de Medicamentos/métodos , Fator VIII/análise , Feminino , Fibrinogênio/análise , Humanos , Gravidez , Complicações Hematológicas na Gravidez/etiologia , Proteína C/análise , Tromboelastografia/métodos , Trombina/biossíntese , Adulto Jovem , Fator de von Willebrand/análise
2.
Phys Rev Lett ; 109(16): 162501, 2012 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-23215070

RESUMO

Two years after the discovery of element 117, we undertook a second campaign using the (249)Bk+(48)Ca reaction for further investigations of the production and decay properties of the isotopes of element 117 on a larger number of events. The experiments were started in the end of April 2012 and are still under way. This Letter presents the results obtained in 1200 hours of an experimental run with the beam dose of (48)Ca of about 1.5×10(19) particles. The (249)Bk target was irradiated at two energies of (48)Ca that correspond to the maximum probability of the reaction channels with evaporation of three and four neutrons from the excited (297)117. In this experiment, two decay chains of (294)117 (3n) and five decay chains of (293)117 (4n) were detected. In the course of the long-term work, (249)Cf-the product of decay of (249)Bk (330 d)-is being accumulated in the target. Consequently, in the present experiment, we also detected a single decay of the known isotope (294)118 that was produced during 2002-2005 in the reaction (249)Cf((48)Ca,3n)(294)118. The obtained results are compared with the data from previous experiments. The experiments are carried out in the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, using the heavy-ion cyclotron U400.

3.
Phys Rev Lett ; 108(2): 022502, 2012 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-22324675

RESUMO

Results of a new series of experiments on the study of production cross sections and decay properties of the isotopes of element 115 in the reaction (243)Am+(48)Ca are presented. Twenty-one new decay chains originating from (288)115 were established as the product of the 3n-evaporation channel by measuring the excitation function at three excitation energies of the compound nucleus (291)115. The decay properties of all newly observed nuclei are in full agreement with those we measured in 2003. At the lowest excitation energy E*=33 MeV, for the first time we registered the product of the 2n-evaporation channel, (289)115, which was also observed previously in the reaction (249)Bk+(48)Ca as the daughter nucleus of the decay of (293)117. The maximum cross section for the production of (288)115 is found to be 8.5 pb at E*≈36 MeV.

4.
J Bone Joint Surg Br ; 94(2): 145-51, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22323676

RESUMO

Persistent groin pain after seemingly successful total hip replacement (THR) appears to have become more common. Recent studies have indicated a high incidence after metal-on-polyethylene and metal-on-metal conventional THR and it has been documented in up to 18% of patients after metal-on-metal resurfacing. There are many causes, including acetabular loosening, stress fracture, and iliopsoas tendonitis and impingement. The evaluation of this problem requires a careful history and examination, plain radiographs and an algorithmic approach to special diagnostic imaging and tests. Non-operative treatment is not usually successful. Specific operative treatment depending on the cause of the pain usually involves revision of the acetabular component, iliopsoas tenotomy or other procedures, and is usually successful. Here, an appropriate algorithm is described.


Assuntos
Artroplastia de Quadril/efeitos adversos , Virilha , Dor Pós-Operatória/etiologia , Algoritmos , Artroplastia de Quadril/métodos , Prótese de Quadril/efeitos adversos , Humanos , Dor Pós-Operatória/diagnóstico , Dor Pós-Operatória/epidemiologia , Dor Pós-Operatória/terapia , Prevalência , Falha de Prótese , Infecções Relacionadas à Prótese/complicações , Infecções Relacionadas à Prótese/diagnóstico , Infecções Relacionadas à Prótese/terapia , Reoperação
5.
Vet Pathol ; 47(6): 1090-4, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20634406

RESUMO

Multicentric cutaneous neuroendocrine (Merkel cell) carcinoma was diagnosed in a 5-year-old castrated male Keeshond dog with multiple firm nodular cutaneous masses. The neoplastic tissue locally effaced the periadnexal and deep dermis and consisted of densely cellular confluent clusters of round to polygonal cells supported by a delicate fibrovascular stroma. The cells were moderately immunoreactive with chromogranin A, synaptophysin, and cytokeratin. Ultrastructurally, the cells had characteristic membrane-bound dense-core neuroendocrine granules approximately 120 nm in diameter and randomly dispersed throughout the cytoplasm. Effacement of dermal structures and multicentric distribution suggested low-grade malignant phenotype. These findings contrast with the typical benign behavior of canine cutaneous neuroendocrine tumors.


Assuntos
Carcinoma de Célula de Merkel/veterinária , Doenças do Cão/patologia , Neoplasias Cutâneas/veterinária , Animais , Carcinoma de Célula de Merkel/patologia , Carcinoma de Célula de Merkel/ultraestrutura , Cromogranina A/metabolismo , Doenças do Cão/metabolismo , Cães , Evolução Fatal , Queratinas/metabolismo , Masculino , Pele/patologia , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/ultraestrutura , Sinaptofisina/metabolismo
6.
Phys Rev Lett ; 104(14): 142502, 2010 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-20481935

RESUMO

The discovery of a new chemical element with atomic number Z=117 is reported. The isotopes (293)117 and (294)117 were produced in fusion reactions between (48)Ca and (249)Bk. Decay chains involving 11 new nuclei were identified by means of the Dubna gas-filled recoil separator. The measured decay properties show a strong rise of stability for heavier isotopes with Z > or = 111, validating the concept of the long sought island of enhanced stability for superheavy nuclei.

7.
Heart ; 94(6): 717-23, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18032459

RESUMO

BACKGROUND: Evidence suggests that an early interventional strategy for patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) can improve health outcomes but also increase costs when compared with a conservative strategy. OBJECTIVE: The aim of this study was to assess the cost-effectiveness of an early interventional strategy in different risk groups from a UK health-service perspective. DESIGN: Decision-analytic model based on randomised clinical trial data. MAIN OUTCOME MEASURES: Costs in UK Sterling at 2003/2004 prices and quality-adjusted life years (QALYs) combined into an incremental cost-effectiveness ratio. METHODS: Data from the third Randomised Intervention Trial of unstable Angina (RITA 3) was employed to estimate rates of cardiovascular death and myocardial infarction, costs and health-related quality of life. Cost-effectiveness was estimated over patients' lifetimes within the decision-analytic model. RESULTS: The mean incremental cost per QALY gained for an early interventional strategy was approximately 55,000 pounds sterling, 22,000 pounds sterling and 12,000 pounds sterling for patients at low, intermediate and high risk, respectively. The early interventional strategy is approximately 1%, 35% and 95% likely to be cost-effective for patients at low, intermediate and high risk, respectively, at a threshold of 20,000 pounds sterling per QALY. The cost-effectiveness of early intervention in low-risk patients is sensitive to assumptions about the duration of the treatment effect. CONCLUSION: An early interventional strategy in patients presenting with NSTE-ACS is likely to be considered cost-effective for patients at high and intermediate risk, but this is less likely to be the case for patients at low risk.


Assuntos
Síndrome Coronariana Aguda/economia , Angiografia Coronária/economia , Anos de Vida Ajustados por Qualidade de Vida , Síndrome Coronariana Aguda/mortalidade , Síndrome Coronariana Aguda/terapia , Idoso , Idoso de 80 Anos ou mais , Angina Instável/economia , Angina Instável/terapia , Análise Custo-Benefício/economia , Custos e Análise de Custo , Angiopatias Diabéticas/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Multicêntricos como Assunto , Modelos de Riscos Proporcionais , Ensaios Clínicos Controlados Aleatórios como Assunto
8.
Heart ; 92(10): 1473-9, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16621882

RESUMO

OBJECTIVE: To determine whether, in acute non-ST elevation coronary syndrome, the benefit from early invasive coronary intervention compared with a conservative strategy of later symptom-guided intervention varies over time. METHODS: In RITA 3 (Randomised Intervention Trial of unstable Angina 3) patients were randomly assigned to coronary angiography (median 2 days after randomisation) and appropriate intervention (n = 895) or to a symptom-guided conservative strategy (n = 915). RESULTS: In the first week patients in both groups were at highest risk of death, myocardial infarction (MI) or refractory angina (incidence rate 40 times higher than in months 5-12 of follow up). There were 22 MIs and 6 deaths in the intervention group (largely due to procedure-related events, 14 MIs and 3 deaths) versus 17 MIs and 3 deaths in the conservative group. In the rest of the year there were an additional 12 versus 27 MIs, respectively (treatment-time interaction p = 0.021). Over one year in the intervention group there was a 43% reduction in refractory angina; 22% of patients underwent coronary artery bypass surgery and 35% underwent percutaneous coronary intervention only, which reduced refractory angina but provoked some early MIs; and 43% were still treated medically, mostly because of a favourable initial angiogram. CONCLUSION: Any intervention policy needs to recognise the high risk of events in the first week and the substantial minority of patients not needing intervention. Intervention may be best targeted at higher risk patients, as the early hazards of the procedure are then offset by reduced subsequent events.


Assuntos
Angina Instável/terapia , Adulto , Idoso , Angina Instável/mortalidade , Ponte de Artéria Coronária , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/etiologia , Infarto do Miocárdio/mortalidade , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/antagonistas & inibidores , Recidiva , Fatores de Risco , Análise de Sobrevida , Resultado do Tratamento
9.
Lancet ; 366(9489): 914-20, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16154018

RESUMO

BACKGROUND: The long-term outcome of an interventional strategy in patients with non-ST-elevation acute coronary syndrome is unknown. We tested whether an interventional strategy (routine angiography followed by revascularisation) was better than a conservative strategy (ischaemia-driven or symptom-driven angiography) over 5 years' follow-up. METHODS: In a multicentre randomised trial, 1810 patients (from 45 hospitals in England and Scotland, UK) with non-ST-elevation acute coronary syndrome were randomly assigned to receive an early intervention (n=895) or a conservative strategy (n=915) within 48 h of the index episode of cardiac pain. In each group, the aim was to provide the best medical treatment, and also to undertake coronary arteriography within 72 h in the interventional strategy with subsequent management guided by the angiographic findings. Analysis was by intention to treat and the primary outcome (composite of death or non-fatal myocardial infarction) had masked independent adjudication. RITA 3 has been assigned the International Standard Randomised Control Trial Number ISRCTN07752711. FINDINGS: At 1-year follow-up, rates of death or non-fatal myocardial infarction were similar. However, at a median of 5 years' follow-up (IQR 4.6-5.0), 142 (16.6%) patients with intervention treatment and 178 (20.0%) with conservative treatment died or had non-fatal myocardial infarction (odds ratio 0.78, 95% CI 0.61-0.99, p=0.044), with a similar benefit for cardiovascular death or myocardial infarction (0.74, 0.56-0.97, p=0.030). 234 (102 [12%] intervention, 132 [15%] conservative) patients died during follow-up (0.76, 0.58-1.00, p=0.054). The benefits of an intervention strategy were mainly seen in patients at high risk of death or myocardial infarction (p=0.004), and for the highest risk group, the odds ratio of death or non-fatal myocardial infarction was 0.44 (0.25-0.76). INTERPRETATION: In patients with non-ST-elevation acute coronary syndrome, a routine invasive strategy leads to long-term reduction in risk of death or non-fatal myocardial infarction, and this benefit is mainly in high-risk patients. The findings provide support for national and international guidelines in the need for more robust risk stratification in acute coronary syndrome.


Assuntos
Angina Instável/terapia , Eletrocardiografia , Infarto do Miocárdio/terapia , Angina Instável/diagnóstico , Causas de Morte , Angiografia Coronária , Seguimentos , Humanos , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/mortalidade , Revascularização Miocárdica
10.
Eur Heart J ; 25(18): 1641-50, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15351164

RESUMO

AIMS: The RITA 3 trial randomized patients with non-ST-elevation myocardial infarction or unstable angina to strategies of early intervention (angiography followed by revascularization) or conservative care (ischaemia or symptom driven angiography). The aim of this analysis was to investigate the impact of gender on the effect of these two strategies. METHODS AND RESULTS: In total, 1810 patients (682 women and 1128 men) were randomized. The risk factor profile of women at presentation was markedly different to men. There was evidence that men benefited more from an early intervention strategy for death or non-fatal myocardial infarction at 1 year (adjusted odds ratios 0.63, 95% confidence interval 0.41-0.98 for men and 1.79, 95% confidence interval 0.95-3.35 for women; interaction p-value=0.007). Men who underwent the assigned angiogram were more likely to be put forward for coronary artery bypass surgery, even after allowing for differences in disease severity. CONCLUSION: An early intervention strategy resulted in a beneficial effect in men which was not seen in women although caution is needed in interpretation. Further research is needed to evaluate why women do not appear to benefit from early intervention and to identify treatments that improve the prognosis of women.


Assuntos
Angina Instável/terapia , Angioplastia Coronária com Balão/estatística & dados numéricos , Infarto do Miocárdio/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Revascularização Miocárdica , Medição de Risco , Fatores de Risco , Fatores Sexuais , Análise de Sobrevida , Resultado do Tratamento
12.
Int J Obes Relat Metab Disord ; 28(6): 727-33, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15079159

RESUMO

BACKGROUND: Ghrelin, a 28 amino-acid peptide secreted primarily from the stomach has been identified as the endogenous ligand for the growth hormone secretagogue receptor. Ghrelin is suppressed in the postprandial state and has been linked to both type II diabetes and obesity. AIMS: To investigate the effects of a period of overfeeding with high-fat dietary supplements on plasma ghrelin levels in nonobese men. METHODS: Six healthy males (21-34 y; BMI 21-24 kg/m(2)) underwent the dietary intervention after completing diet and exercise diaries for 7 days. For 3 further weeks subjects followed their own diet diary supplemented with 125 ml single cream and 50 g roasted peanuts (88 g fat, 15 g Protein, 8 g carbohydrate) every day. Oral fat tolerance tests (OFTT) were undertaken at baseline, 7, 14 and 21 days of fat supplementation. The diet was increased in energy by 3.9 MJ/day and from a mean of 29-45% energy intake from fat with a small weight gain noted each week (P=0.009). RESULTS: Ghrelin concentrations were significantly reduced during the baseline OFTT. The postprandial ghrelin response (AUC) was significantly reduced following 2 weeks of dietary supplementation (P=0.005) increasing the suppression of plasma ghrelin by 18% despite only a 3% increase in body weight. Plasma triacylglycerol (P=0.009) and leptin (P=0.035) concentrations were also elevated and postprandial pancreatic polypeptide levels decreased (P=0.038) following dietary-supplementation. CONCLUSIONS: These results suggest that the metabolic profile associated with obesity, including a reduction in plasma ghrelin levels, may be related to recent dietary energy intake and precedes the development of significant adiposity.


Assuntos
Peso Corporal/fisiologia , Gorduras na Dieta/administração & dosagem , Ingestão de Alimentos/fisiologia , Hormônios Peptídicos/sangue , Adulto , Análise de Variância , Ácidos Graxos não Esterificados/sangue , Esvaziamento Gástrico/fisiologia , Grelina , Humanos , Leptina/sangue , Masculino , Período Pós-Prandial , Triglicerídeos/sangue , Aumento de Peso/fisiologia
13.
Lancet ; 360(9335): 743-51, 2002 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-12241831

RESUMO

BACKGROUND: Current guidelines suggest that, for patients at moderate risk of death from unstable coronary-artery disease, either an interventional strategy (angiography followed by revascularisation) or a conservative strategy (ischaemia-driven or symptom-driven angiography) is appropriate. We aimed to test the hypothesis that an interventional strategy is better than a conservative strategy in such patients. METHODS: We did a randomised multicentre trial of 1810 patients with non-ST-elevation acute coronary syndromes (mean age 62 years, 38% women). Patients were assigned an early intervention or conservative strategy. The antithrombin agent in both groups was enoxaparin. The co-primary endpoints were a combined rate of death, non-fatal myocardial infarction, or refractory angina at 4 months; and a combined rate of death or non-fatal myocardial infarction at 1 year. Analysis was by intention to treat. FINDINGS: At 4 months, 86 (9.6%) of 895 patients in the intervention group had died or had a myocardial infarction or refractory angina, compared with 133 (14.5%) of 915 patients in the conservative group (risk ratio 0.66, 95% CI 0.51-0.85, p=0.001). This difference was mainly due to a halving of refractory angina in the intervention group. Death or myocardial infarction was similar in both treatment groups at 1 year (68 [7.6%] vs 76 [8.3%], respectively; risk ratio 0.91, 95% CI 0.67-1.25, p=0.58). Symptoms of angina were improved and use of antianginal medications significantly reduced with the interventional strategy (p<0.0001). INTERPRETATION: In patients presenting with unstable coronary-artery disease, an interventional strategy is preferable to a conservative strategy, mainly because of the halving of refractory or severe angina, and with no increased risk of death or myocardial infarction.


Assuntos
Angina Pectoris/terapia , Cardiotônicos/uso terapêutico , Ponte de Artéria Coronária , Doença das Coronárias/terapia , Infarto do Miocárdio/terapia , Angina Pectoris/etiologia , Angina Pectoris/mortalidade , Aterectomia Coronária , Angiografia Coronária , Doença das Coronárias/complicações , Doença das Coronárias/mortalidade , Determinação de Ponto Final , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/etiologia , Infarto do Miocárdio/mortalidade , Fatores de Risco , Reino Unido
14.
Eur Heart J ; 23(1): 50-8, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11741362

RESUMO

AIMS: To assess the direct medical costs and cost effectiveness of routine eptifibatide use amongst patients with unstable angina and myocardial infarction without persistent ST-segment elevation in the Western European subgroup of the PURSUIT trial. METHODS AND RESULTS: Health care resources were collected for the Western European PURSUIT trial patients (n=3697). Unit costs for major resources were developed within six countries using a consistent bottom-up methodology. Resource consumption from the Western European population was used to calculate the average direct medical costs per patient in the eptifibatide and placebo arms of the trial. Eptifibatide was estimated to cost 524 Euros per treatment. Long-term survival estimated from the 6-month trial survival data and combined with the cost data was used to calculate cost-effectiveness ratios. Additionally, cost per death and non-fatal myocardial infarction at 30 days was calculated. Sensitivity analyses were conducted on the discount rate and resource consumption. Cost-effectiveness ratios ranged from 9603 Euros to 18 115 Euros per year of life saved with 3% discount. Using resource consumption based on countries with low coronary arteriography rates, the cost per year of life saved was between 3329 Euros and 10 079 Euros. Using resource consumption based on high coronary arteriography rate countries, the cost per year of life saved was between 17 089 Euros and 24 099 Euros. Assuming no difference in treatment costs except for the addition of eptifibatide, the incremental cost per year of life saved was 23 818 Euros. CONCLUSIONS: Routine eptifibatide use was associated with a reduction in the combined end-point of death and myocardial infarction at 30 days, which was sustained at 6 months. Long-term projections indicate a modest increase in survival in eptifibatide patients. These data translate into cost-effectiveness ratios that compare favourably with other new technologies that are currently in use.


Assuntos
Doença das Coronárias/tratamento farmacológico , Doença das Coronárias/economia , Peptídeos/economia , Peptídeos/uso terapêutico , Inibidores da Agregação Plaquetária/economia , Inibidores da Agregação Plaquetária/uso terapêutico , Doença Aguda , Idoso , Ponte de Artéria Coronária/economia , Doença das Coronárias/cirurgia , Efeitos Psicossociais da Doença , Análise Custo-Benefício/economia , Técnicas de Diagnóstico Cardiovascular/economia , Determinação de Ponto Final , Eptifibatida , Europa (Continente)/epidemiologia , Feminino , Custos de Cuidados de Saúde , Humanos , Expectativa de Vida , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/economia , Infarto do Miocárdio/cirurgia , Admissão do Paciente/economia , Sensibilidade e Especificidade , Análise de Sobrevida , Síndrome , Resultado do Tratamento
16.
J Appl Physiol (1985) ; 90(5): 1887-99, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11299283

RESUMO

We previously reported (J Appl Physiol 89: 807-822, 2000) that < or =10 min of hyperbaric oxygen (HBO(2); < or = 2,468 Torr) stimulates solitary complex neurons. To better define the hyperoxic stimulus, we measured PO(2) in the solitary complex of 300-microm-thick rat medullary slices, using polarographic carbon fiber microelectrodes, during perfusion with media having PO(2) values ranging from 156 to 2,468 Torr. Under control conditions, slices equilibrated with 95% O(2) at barometric pressure of 1 atmospheres absolute had minimum PO(2) values at their centers (291 +/- 20 Torr) that were approximately 10-fold greater than PO(2) values measured in the intact central nervous system (10-34 Torr). During HBO(2), PO(2) increased at the center of the slice from 616 +/- 16 to 1,517 +/- 15 Torr. Tissue oxygen consumption tended to decrease at medium PO(2) or = 1,675 Torr to levels not different from values measured at PO(2) found in all media in metabolically poisoned slices (2-deoxy-D-glucose and antimycin A). We conclude that control medium used in most brain slice studies is hyperoxic at normobaric pressure. During HBO(2), slice PO(2) increases to levels that appear to reduce metabolism.


Assuntos
Tronco Encefálico/fisiologia , Consumo de Oxigênio , Oxigênio/análise , Animais , Antimicina A/farmacologia , Tronco Encefálico/efeitos dos fármacos , Calibragem , Desoxiglucose/farmacologia , Eletroquímica/métodos , Oxigenoterapia Hiperbárica , Hiperóxia , Técnicas In Vitro , Pressão Parcial , Ratos , Ratos Sprague-Dawley
17.
Am J Clin Nutr ; 73(4): 821-6, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11273859

RESUMO

BACKGROUND: Early diagnostic efforts and advances in multidrug therapy have considerably prolonged the survival time of children infected perinatally with HIV. Despite these advances, few studies have addressed calcium status and bone growth in HIV-infected children. OBJECTIVE: Our objective was to examine the effect of HIV infection on calcium status and bone growth in children. DESIGN: We measured calcitropic hormones, urinary calcium excretion, bone mineral content, and body composition in 19 young girls aged 9.2 +/- 2.6 y (range: 5.9-15.2 y) who were infected perinatally with HIV. RESULTS: Serum concentrations of 1,25-dihydroxyvitamin D [1,25(OH)(2)D] and parathyroid hormone concentrations were elevated above normal ranges in 25% and 12% of these girls, respectively. Urinary calcium excretion normalized for creatinine excretion was also elevated (Ca/Cr >0.18) in 17% of these children despite suboptimal calcium intakes (679 +/- 437 mg/d). Total-body bone mineral content, measured with the use of dual-energy X-ray absorptiometry, averaged 845.1 +/- 279.0 g and was on average 2.7 z scores below age- and race-matched values reported in non-HIV-infected healthy girls. Significant positive correlations were found between an indirect marker of bone resorption in urine (N:-telopeptide) and 1,25(OH)2D (P < 0.02, r2 = 0.586, n = 9), and between serum N-telopeptide and total alkaline phosphatase (P < 0.001, r2 = 0.541, n = 17), suggesting that calcium insufficiency may be increasing bone resorption in this group. CONCLUSIONS: Young girls with HIV infection had low bone mass and evidence of calcium insufficiency. Nutritional counseling of children with HIV infection should emphasize adequate calcium intakes because of the importance of this age period in bone mineral acquisition.


Assuntos
Densidade Óssea/fisiologia , Calcitriol/sangue , Cálcio/análise , Infecções por HIV/complicações , Hormônio Paratireóideo/sangue , Absorciometria de Fóton , Adolescente , Fenômenos Fisiológicos da Nutrição do Adolescente , População Negra , Composição Corporal , Desenvolvimento Ósseo , Reabsorção Óssea , Cálcio/deficiência , Criança , Fenômenos Fisiológicos da Nutrição Infantil , Pré-Escolar , Creatinina/urina , Feminino , Humanos , Rememoração Mental , Assistência Perinatal , População Branca
19.
Adv Exp Med Biol ; 475: 465-76, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10849687

RESUMO

Hyperbaric oxygen (HBO2) at approximately 3 atmospheres absolute (ATA) pressure is toxic to the mammalian CNS due to excessive O2 free radical production. No study has ever determined the effects of < or = 3 ATA of O2 on the membrane potential and firing rate of neurons in the mammalian brainstem. Likewise, no study has ever determined the effects of < or = 3 ATA pressure per se on brainstem neurons. Accordingly, we initiated intracellular recordings at 1 ATA in solitary complex neurons in slices (300 microns) of rat caudal medulla oblongata that were maintained inside a 72 liter hyperbaric chamber. Helium, which is inert and without narcotic effect at moderate levels of hyperbaria, was used to hydrostatically compress the submerged brain slice to determine the effects of pressure per se. Tissue oxygen tension and extracellular pH were also measured during exposure to hyperbaric gases. Six of 19 neurons were affected by hyperbaric helium; 5 cells were depolarized and 1 cell was hyperpolarized. Input resistance (Rin) either increased (n = 1) or decreased (n = 3). When control perfusate (0.95 ATA O2) was switched to perfusate saturated with 98% O2 (balance CO2, pH = 7.3-7.4, pO2 = 2.5-3.4 ATA; 2-18 minutes of exposure) in a separate pressure vessel, 8 of 13 neurons were depolarized and 5 neurons were insensitive. In the 8 O2-responsive neurons, Rin either increased (n = 5), decreased (n = 2) or was unchanged (n = 1). Three of 8 neurons depolarized by HBO2 were also depolarized by hyperbaric helium, usually with an additional change in Rin. We conclude that hydrostatic (helium) pressure and HBO2 independently increase excitability in certain solitary complex neurons. We hypothesize that these responses contribute, in part, to neural events that either precede or occur during CNS O2 toxicity.


Assuntos
Oxigenoterapia Hiperbárica/efeitos adversos , Núcleo Solitário/metabolismo , Animais , Pressão Atmosférica , Células Quimiorreceptoras/metabolismo , Feminino , Radicais Livres/metabolismo , Hélio , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Masculino , Potenciais da Membrana , Neurônios/metabolismo , Oxigênio/metabolismo , Pressorreceptores/metabolismo , Ratos , Ratos Sprague-Dawley
20.
Shock ; 13(4): 320-4, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10774622

RESUMO

This study examines the early time course in core temperature change and oxygen consumption at 4 levels of hemorrhage. Chronically instrumented rats were acclimatized to a respirometry chamber for 30 min. The rats were briefly (10 min) removed from the chamber for a fixed volume hemorrhage of 0 mL/kg (sham), 8 mL/kg, 16 mL/kg, 24 mL/kg, or 32 mL/kg. Rats were then returned to the chamber, and oxygen consumption and body core temperature were monitored for the next 2 h. Oxygen consumption (control 1.26 mL O2/g/h) fell significantly 5 min after hemorrhage in all but the sham and 8 mL/kg hemorrhage groups, with the decrease proportional to the hemorrhage volume. The 32 mL/kg hemorrhage group showed the greatest decrease, to 0.47 mL O2/g/h. Body core temperature (control 37.5 degrees C) fell more gradually, declining to 35.6 degrees C 110 min after the 24 mL/kg hemorrhage, and to 33.2 degrees C at 6 h after the 32 mL/kg hemorrhage. In the 16 mL/kg hemorrhage group, oxygen consumption fell significantly by 5 min after hemorrhage, but a drop in body temperature was not seen until 25 min after hemorrhage. The data from this study indicate that the drop in core temperature does not cause the observed decrease in oxygen consumption. In fact, the timing and magnitude of the drop in oxygen consumption indicate that the reduced metabolic rate may mediate the hemorrhage-induced drop in body core temperature in conscious rats.


Assuntos
Temperatura Corporal , Hemorragia/fisiopatologia , Consumo de Oxigênio , Animais , Calorimetria , Masculino , Ratos , Ratos Sprague-Dawley , Valores de Referência , Fatores de Tempo
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