RESUMO
BACKGROUND: The majority of antimicrobial stewardship programmes focus on prescribing in adult populations; however, there is a recognized need for targeted paediatric antimicrobial stewardship to improve the quality and safety of prescribing amongst this patient group. OBJECTIVES: To describe the current epidemiology of antimicrobial prescribing in paediatric inpatient populations in Scotland to establish a baseline of evidence and identify priority areas for quality improvement to support a national paediatric antimicrobial stewardship programme. METHODS: A total of 559 paediatric inpatients were surveyed during the Scottish national point prevalence survey of healthcare-associated infections and antimicrobial prescribing, 2016. The prevalence of antimicrobial prescribing was calculated and characteristics of antimicrobial prescribing were described as proportions and compared between specialist hospitals and paediatric wards in acute hospitals. RESULTS: Prevalence of antimicrobial use in paediatric inpatients was 35.4% (95% CIâ=â31.6%-39.4%). Treatment of community- and hospital-acquired infections accounted for 47.1% and 20.7% of antimicrobial use, respectively, with clinical sepsis being the most common diagnosis and gentamicin the most frequently prescribed antimicrobial for the treatment of infection. The reason for prescribing was documented in the notes for 86.5% of all prescriptions and, of those assessed for compliance against local policy, 92.9% were considered compliant. CONCLUSIONS: Data from national prevalence surveys are advantageous when developing antimicrobial stewardship programmes. Results have highlighted differences in the prescribing landscape between paediatric inpatient populations in specialist hospitals and acute hospitals, and have informed priorities for the national antimicrobial stewardship programme, which reinforces the need for a targeted paediatric antimicrobial stewardship programme.
Assuntos
Antibacterianos/uso terapêutico , Gestão de Antimicrobianos/estatística & dados numéricos , Adolescente , Criança , Pré-Escolar , Doenças Transmissíveis/tratamento farmacológico , Infecção Hospitalar/tratamento farmacológico , Prescrições de Medicamentos/estatística & dados numéricos , Uso de Medicamentos/estatística & dados numéricos , Feminino , Hospitais , Humanos , Prescrição Inadequada/estatística & dados numéricos , Lactente , Recém-Nascido , Pacientes Internados/estatística & dados numéricos , Masculino , Padrões de Prática Médica/estatística & dados numéricos , Prevalência , Melhoria de Qualidade/estatística & dados numéricos , Escócia , Inquéritos e Questionários/estatística & dados numéricosRESUMO
The majority of dairy calves around the world are dehorned with methods that cause them pain and distress. In some dairy production systems, extensionists may influence dehorning practices used on farm through their advisory and knowledge-transfer role. The aims of this study were to investigate Brazilian extensionists' knowledge, beliefs, and behavior regarding dehorning dairy calves. As little research has addressed this question, a qualitative, theory-building approach was used and the theory of planned behavior was used as a conceptual framework to guide data collection and analysis. In-depth, semi-structured interviews were undertaken with 15 extensionists working in Santa Catarina, Brazil, to examine their role in the adoption and rejection of pain-mitigation strategies at dehorning. The interview transcripts were free coded, identifying 9 major themes within and across interviews. Transcribed interview responses were then coded to constructs in the theory of planned behavior. The themes and constructs that emerged through analysis of the interview responses were combined to develop a conceptual model of extensionists' beliefs, attitudes, and behavior toward recommending protocols for dehorning aimed at minimizing pain. The extensionists interviewed believed that it was necessary to dehorn all dairy replacement heifers. Despite being aware of methods to minimize pain during and after dehorning, all of the interviewees recommended or used the hot cautery method, with no pain control. This method was described as the most effective, cheapest, safest, and fastest method of dehorning. The majority (12) of interviewees rejected the caustic paste method, citing negative past experiences or unfamiliarity with the method and the belief that the method is less practical and riskier for farmers. More than half of the interviewees did not recognize dehorning as painful or expressed the belief that the pain associated with the procedure did not justify the use of pain control. Although a small number of extensionists (4) recognized potential sources of social pressure to change, including the rejection of pain-inflicting practices by some farmers, the Brazilian general public, and animal-protection societies, they did not identify these factors as a reason to change their existing practices. Interviewees expressed the belief that the adoption of practices to minimize pain and stress, such as dehorning very young calves, using caustic paste and pain control, would increase labor and costs associated with dehorning. Extensionists' negative attitudes toward recommending practices that minimize pain during and after dehorning appear to be embedded in the production-focused political and economic agriculture environment and a lack of education, research, and legislation regarding farm animal welfare.
Assuntos
Bovinos/cirurgia , Indústria de Laticínios/métodos , Cornos/cirurgia , Manejo da Dor/veterinária , Bem-Estar do Animal , Animais , Atitude , Brasil , Entrevistas como Assunto , Dor/veterináriaRESUMO
BACKGROUND: The link between inappropriate antibiotic prescribing and the global threat of antimicrobial resistance is well documented. International strategies recommend antimicrobial stewardship (AMS) programmes, with improvement interventions to safeguard antibiotics. AIM: This study sought to systematically evaluate the impact of multi-professional Antimicrobial Management Team (AMT) staff resource availability on stewardship activities. METHODS: We conducted an on-line, cross-sectional survey of AMTs in each regional Health Board and the national specialist hospital in Scotland (N = 15). Responses were analysed descriptively, exploring observed relationships between variables to identify patterns. FINDINGS: Results highlighted apparent variation in the levels of AMT resource availability across Scotland, not directly influenced by Health Board size, with some larger Health Boards having proportionately poorer AMT resource allocation. However, the range and frequency of activities to support AMS was not directly linked to either Health Board size or staff resource allocation, indicating a more complex inter-relationship between factors. CONCLUSIONS: There is apparent inequity in staff resource available for AMTs across Scotland, with significantly lower resource allocation in comparison with recommendations from other international studies. However, considering these survey findings with our earlier qualitative research indicates that leadership style and team member enthusiasm may be as, if not more, influential than resource availability on the scope of AMT activities. These findings have international relevance for hospital service managers considering the recruitment, training and ongoing support of AMTs, in order to maximize impact from a limited resource.
Assuntos
Anti-Infecciosos , Gestão de Antimicrobianos , Antibacterianos/uso terapêutico , Estudos Transversais , Humanos , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Healthcare-associated infections (HCAIs) are a major public health concern and a significant cause of morbidity and mortality. A robust and current evidence base that is specific to local, national and Europe-wide settings is necessary to inform the development of strategies to reduce HCAI and contain antimicrobial resistance. AIM: To measure the prevalence of HCAI and antimicrobial prescribing and identify key priority areas for interventions to reduce the burden of infection. METHODS: A national rolling point-prevalence survey (PPS) in National Health Service (NHS) acute, NHS non-acute, NHS paediatric, and independent hospitals was carried out between September and November 2016 using the European Centre for Disease Prevention and Control protocol designed for the European PPS. FINDINGS: The prevalence of HCAI was 4.6%, 2.7%, and 3.2% in acute adults, paediatric and non-acute patient groups, respectively. The most frequent HCAI types reported in adult patients were urinary tract infection and pneumonia. The prevalence of antimicrobial prescribing was 35.7%, 29.3%, and 13.8% in acute adults, paediatric, and non-acute patient groups, respectively. Respiratory, skin and soft tissue, gastrointestinal, and urinary tract infections were the most common infections being treated at the time of survey. CONCLUSION: HCAI continues to be a public health concern in Scotland. Urinary tract infection and pneumonia continue to place a significant burden on patients and on healthcare delivery, including those that develop in the community and require hospital admission. A broader population health approach which focuses on reducing the risk of infection upstream would reduce these infections in both community and hospital settings.
Assuntos
Infecção Hospitalar/epidemiologia , Infecção Hospitalar/prevenção & controle , Transmissão de Doença Infecciosa/prevenção & controle , Controle de Infecções/métodos , Controle de Infecções/organização & administração , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anti-Infecciosos/uso terapêutico , Criança , Pré-Escolar , Prescrições de Medicamentos , Uso de Medicamentos , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Saúde da População , Prevalência , Escócia/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Healthcare professionals are involved in an array of patient- and medicine-related stewardship activities, for which an understanding and engagement with antimicrobial stewardship (AMS) is important. Undergraduate education provides an ideal opportunity to prepare healthcare professionals for these roles and activities. AIM: To provide UK national consensus on a common set of antimicrobial stewardship competencies appropriate for undergraduate healthcare professional education. METHODS: A modified Delphi approach comprising two online surveys delivered to a UK national panel of 21 individuals reflecting expertise in prescribing and medicines management with regards to the education and practice of nurses and midwives, pharmacists, physiotherapists, and podiatrists; and antimicrobial prescribing and stewardship. Data collection took place between October and December 2017. FINDINGS: A total of 21 participants agreed to become members of the expert panel, of whom 19 (90%) completed round 1 questionnaire, and 17 (89%) completed round 2. Panelists reached a consensus, with consistently high levels of agreement reached, on six overarching competency statements (subdivided into six domains), and 55 individual descriptors essential for antimicrobial stewardship by healthcare professionals. CONCLUSION: Due to the consistently high levels of agreement reached on competency statements and their associated descriptors, this competency framework should be used to direct education for undergraduate healthcare professionals, and those working in new clinical roles to support healthcare delivery where an understanding of, and engagement with, AMS is important. Although the competencies target basic education, they can also be used for continuing education.
Assuntos
Gestão de Antimicrobianos , Consenso , Educação Médica/métodos , Técnica Delphi , Humanos , Inquéritos e Questionários , Reino UnidoRESUMO
Franz diffusion cells containing uniformly dehydrated equine blood clots to simulate fibrinous eschar were used to measure the rate of debridement of fibrin by novel and traditional wound dressings, under standardised conditions of temperature, pH and humidity. Significant increases in protein breakdown occurred within 24 hours with all the dressings, but not thereafter. In general, dressings hydrated in normal saline were better as debriding agents than dressings hydrated in water. Autolytic debriding agents were 47 per cent more effective than chemical debriding agents; specifically, hydrofibre and gauze dressings hydrated in saline broke down more than 3500 microg/ml of protein whereas dressings impregnated with proteolytic enzymatic agents digested less than 1400 microg/ml.
Assuntos
Bandagens/veterinária , Desbridamento/veterinária , Cicatrização , Animais , Curativos Hidrocoloides/veterinária , Coagulação Sanguínea/fisiologia , Colagenases/uso terapêutico , Desbridamento/métodos , Fibrina/efeitos dos fármacos , Cavalos , Umidade , Concentração de Íons de Hidrogênio , Papaína/uso terapêutico , Cloreto de Sódio/uso terapêutico , Estreptoquinase/uso terapêutico , Temperatura , Técnicas de Cultura de Tecidos/veterinária , Resultado do Tratamento , Ureia/uso terapêuticoRESUMO
OBJECTIVES: The purpose of this study was to assess vagal tone and cardiopulmonary baroreceptor activity in patients with tilt-induced neurally mediated syncope. BACKGROUND: The causes of individual susceptibility to orthostatic stress leading to recurrent neurally mediated syncope remain obscure. The trigger for sympathetic withdrawal and increased vagal activity is believed to be stimulation of ventricular mechanoreceptors. METHODS: Seventeen patients (mean age 50.6 years) with recurrent syncope and a positive response on a 45-min 60 degrees head-up tilt test were compared with a control group of 17 patients (mean age 47.5 years) with unexplained syncope and negative tilt test findings. Vagal activity was assessed by high pressure baroreceptor testing and by temporal and spectral analysis of heart rate variability during Holter ambulatory electrocardiographic monitoring. Cardiopulmonary baroreceptor sensitivity was assessed by measurement of forearm vascular responses to lower body negative pressure. RESULTS: Mean high pressure baroreceptor sensitivity was 16.4 +/- 12.2 ms/mm Hg in the group with a positive tilt test response compared with 15.1 +/- 13.0 ms/mm Hg in the control group (p = NS). There were no significant differences between the groups in any of the temporal or spectral measures of heart rate variability. The increase in forearm vascular resistance in response to lower body negative pressure was 11.5 +/- 14.2 U in patients with tilt-induced syncope and 3.5 +/- 3.2 U in the control group at -5 mm Hg, 16.8 +/- 18.6 U and 4.8 +/- 5.3 U, respectively, at -10 mm Hg and 26.4 +/- 24.3 U and 10.2 +/- 7.8 U, respectively, at -20 mm Hg (p < 0.001). CONCLUSIONS: Patients with tilt-induced neurally mediated syncope have augmented cardiopulmonary baroreceptor responses to orthostatic stress. This finding sheds new light on the etiology of neurally mediated syncope.
Assuntos
Sistema Cardiovascular/fisiopatologia , Pulmão/fisiopatologia , Postura/fisiologia , Pressorreceptores/fisiopatologia , Estresse Fisiológico/complicações , Síncope/etiologia , Nervo Vago/fisiopatologia , Adulto , Idoso , Pressão Sanguínea/fisiologia , Temperatura Baixa/efeitos adversos , Feminino , Antebraço/irrigação sanguínea , Humanos , Masculino , Pessoa de Meia-Idade , Fluxo Sanguíneo Regional , Síncope/fisiopatologia , Resistência VascularRESUMO
Immediate responses to head-up tilt were determined in 78 consecutive patients with unexplained syncope undergoing 45-minute tilt tests at 60 degrees. Thirty-four patients developed neurally mediated syncope (mean time to syncope 18 minutes), 40 tolerated the full duration of tilt, and 4 were unable to complete the study but did not develop syncope. Blood pressure, heart rate, forearm blood flow and forearm vascular resistance were measured at baseline and after 2 and 5 minutes of tilt. Syncopal and nonsyncopal patients were well-matched for age and baseline hemodynamic parameters. There was no difference between the groups in heart rate or blood pressure at 2 minutes, but there was a small but significant difference in percent reduction in mean arterial pressure at 5 minutes. After 2 and 5 minutes of tilt, mean forearm blood flow was 2.4 and 2.6 ml/min/100 ml, respectively, in syncopal patients compared with 1.6 (p < 0.05) and 1.7 ml/min/100 ml (p < 0.01), respectively, in patients who tolerated 45 minutes of tilt. In syncopal patients, forearm vascular resistance was 51.0 and 44.0 at 2 and 5 minutes, respectively, whereas in nonsyncopal patients, it was 82.4 (p < 0.02) and 73.1 (p < 0.001), respectively. These differences remained consistent when only data for patients developing syncope after > 15 minutes were included in the analysis. Patients with neurally mediated syncope have clearly demonstrable abnormalities in vascular control immediately after assumption of the upright posture. The results shed new light on the pathophysiology of neurally mediated syncope.
Assuntos
Postura , Síncope/fisiopatologia , Nervo Vago/fisiopatologia , Vasoconstrição/fisiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Pressão Sanguínea/fisiologia , Criança , Estudos de Coortes , Feminino , Antebraço/irrigação sanguínea , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva , Fluxo Sanguíneo Regional/fisiologia , Fatores Sexuais , Decúbito Dorsal , Síncope/etiologia , Fatores de Tempo , Resistência Vascular/fisiologiaRESUMO
Magnesium deficiency frequently develops in patients with congestive heart failure and may increase susceptibility to lethal arrhythmias and sudden death via multiple pathophysiologic mechanisms. The effects of peroral magnesium supplementation were investigated in a randomized, double-blind, crossover trial involving 21 patients with stable congestive heart failure secondary to coronary artery disease. All were receiving long-term loop diuretics, and had normal renal function, and low or normal serum magnesium concentrations. Subjects alternately received enteric-coated magnesium chloride (15.8 mmol magnesium per day) and placebo for 6 weeks. Magnesium therapy increased serum magnesium from 0.87 +/- 0.07 to 0.92 +/- 0.05 mmol/liter (p < 0.05), serum potassium from 4.0 +/- 0.3 to 4.3 +/- 0.4 mmol/liter (p < 0.01) and urinary magnesium excretion from 2.82 +/- 0.96 to 4.74 +/- 2.38 mmol/24 hours (p = 0.001). There was no significant change in heart rate or Doppler cardiac index, but mean arterial pressure decreased from 91 +/- 10 to 87 +/- 10 mm Hg (p < 0.05) and systemic vascular resistance from 1,698 +/- 367 to 1,613 +/- 331 dynes s cm-5 (p = 0.047). The frequency of isolated ventricular premature complexes was reduced by 23% (95% confidence interval [CI] 6 to 37%; p < 0.02), couplets by 52% (95% CI 30 to 65%; p < 0.001) and nonsustained ventricular tachycardia episodes by 24% (95% CI 15 to 49%; p < 0.01). Plasma epinephrine decreased from 447 +/- 535 to 184 +/- 106 pg/ml (p = 0.02), but there was no corresponding change in plasma norepinephrine or heart rate variability.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Doença das Coronárias/complicações , Insuficiência Cardíaca/tratamento farmacológico , Cloreto de Magnésio/farmacologia , Cloreto de Magnésio/uso terapêutico , Administração Oral , Adulto , Idoso , Análise de Variância , Doença das Coronárias/fisiopatologia , Método Duplo-Cego , Eletrólitos/sangue , Feminino , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Hemodinâmica/efeitos dos fármacos , Humanos , Cloreto de Magnésio/efeitos adversos , Masculino , Pessoa de Meia-Idade , Taquicardia Ventricular/fisiopatologia , Taquicardia Ventricular/prevenção & controle , Fatores de TempoRESUMO
1. 5-Hydroxytryptamine (5-HT) transport has been investigated in rat blood platelets poisoned with dinitrophenol-sodium fluoride or ouabain.2. The inhibition of transport produced by different concentrations of the metabolic inhibitors has been correlated with changes in the internal Na(+) and K(+) concentrations of the platelets.3. Platelets poisoned in a high K(+) medium maintained a high internal K(+) concentration in the absence of cellular metabolism. When transferred to Krebs solutions containing different concentrations of Na(+) they accumulated 5-HT by a process that was related to the magnitudes of the internal and external Na(+) concentrations.4. The results are consistent with the hypothesis that the spontaneous movement of ions through the platelet membrane is capable of providing, at least in part, the energy requirements for 5-HT transport.
Assuntos
Plaquetas/metabolismo , Potássio/metabolismo , Serotonina/metabolismo , Sódio/metabolismo , Animais , Transporte Biológico Ativo/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Isótopos de Carbono , Dinitrofenóis/farmacologia , Técnicas In Vitro , Masculino , Ouabaína/farmacologia , RatosRESUMO
1. The influence of sodium and potassium on the accumulation of 5-hydroxytryptamine (5-HT) by rat blood platelets was investigated.2. An absolute dependence of 5-HT uptake on the sodium concentration in the medium was found.3. Removal of potassium reduced the uptake by about 60%. High concentrations of potassium inhibited sodium-dependent accumulation.4. The observations have been discussed in terms of a carrier-mediated transport process for 5-HT operating in the platelet membrane.
Assuntos
Transporte Biológico Ativo , Plaquetas/metabolismo , Serotonina/metabolismo , Sódio/farmacologia , Animais , Membrana Celular/metabolismo , Técnicas In Vitro , Cinética , Masculino , Potássio/análise , Potássio/farmacologia , Ratos , Sódio/análise , TrítioRESUMO
1 Metyrapone (150 mg/kg, s.c. or i.p.) an inhibitor of corticosteroid biosynthesis, significantly reduced the release of prostaglandins of the F-type from isolated preparations of pregnant rat uteri in vitro, on day 22 - the expected day of delivery. 2 Metyrapone and indomethacin administered in vitro both inhibited the conversion of 14C-arachidonic acid to prostaglandin E2 by homogenates of day 22 pregnant rat uteri. Metyrapone was approximately 150 times less potent than indomethacin. Although indomethacin also inhibited prostaglandin F2alpha production, metyrapone stimulated synthesis of this prostaglandin. The differential inhibition of prostaglandin synthesis by metyrapone may reflect sensitivity of the inhibitor to changes in experimental conditions. 3 Inhibition of prostaglandin synthesis may explain the effects of metyrapone on parturition in the rat.
Assuntos
Metirapona/farmacologia , Prenhez , Prostaglandinas E/metabolismo , Prostaglandinas F/metabolismo , Útero/metabolismo , Animais , Feminino , Indometacina/farmacologia , Gravidez , Prostaglandina-Endoperóxido Sintases/metabolismo , Prostaglandinas E/biossíntese , Prostaglandinas F/biossíntese , Ratos , Contração Uterina/efeitos dos fármacos , Útero/efeitos dos fármacos , Útero/enzimologiaRESUMO
1 The effect of perturbation of intact blood platelets with proteolytic enzymes was studied with respect to 5-hydroxytryptamine (5-HT) transport, adenine transport and intracellular Na(+) and K(+) levels.2 Leucine aminopeptidase and thrombin reduced 5-HT transport, released 5-HT from pre-labelled platelets and disturbed the gradient to monovalent cations. Leucine amino-peptidase, but not thrombin, inhibited adenine transport.3 alpha-Chymotrypsin and carboxypeptidases A and B were without effect on the parameters studied.4 Trypsin selectively reduced 5-HT transport. It did not release 5-HT from blood platelets or inhibit adenine transport.5 The action of proteolytic enzymes is discussed in terms of proteins localized in the external membrane that may function in part as membrane carriers.
Assuntos
Plaquetas/metabolismo , Peptídeo Hidrolases/farmacologia , Serotonina/metabolismo , Adenina/metabolismo , Animais , Plaquetas/efeitos dos fármacos , Carboxipeptidases/farmacologia , Quimotripsina/farmacologia , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Leucil Aminopeptidase/farmacologia , Potássio/metabolismo , Ratos , Sódio/metabolismo , Trombina/farmacologia , Tripsina/farmacologiaRESUMO
1. Superoxide dismutase (SOD, 60 u ml-1) or ferricytochrome c (70 microM) significantly inhibited thrombin-stimulated platelet adhesion to gelatin-coated plastic, whereas catalase (1000 u ml-1) or mannitol (1 mM) had no effect. 2. The platelet aggregation induced by low concentrations of thrombin (causing less than 45% maximal change in light transmission) was inhibited by SOD. Catalase or mannitol had no effect on platelet aggregation. 3. Pyrogallol (an O2- generator) enhanced both platelet adhesion to gelatin-coated plastic and platelet aggregation induced by thrombin; this enhancement was neutralized by SOD. 4. These results indicate that O2- increase both platelet adhesion and aggregation, whereas other free radicals such as hydrogen peroxide or hydroxyl radicals are not involved.
Assuntos
Adesividade Plaquetária/efeitos dos fármacos , Agregação Plaquetária/efeitos dos fármacos , Superóxidos/farmacologia , Adenina/metabolismo , Catalase/farmacologia , Humanos , Técnicas In Vitro , Manitol/farmacologia , Inibidores da Agregação Plaquetária , Pirogalol/farmacologia , Superóxido Dismutase/farmacologia , Trombina/farmacologiaRESUMO
The release of prostaglandin-like material and these spontaneous contractions of individual horns from the pregnant rat uterus in vitro have been studied on day 22 of pregnancy - the expected day of delivery. Removal of foetuses (retaining placentae in utero) from one or both uterine horns on day 16 or 17 significantly reduced prostaglandin F release and spontaneous activity. Rats which had been made unilaterally pregnant after ligation of one uterine horn, exhibited a decrease in prostaglandin F output from both horns. Uterine activity and prostaglandin release were increased in quiescent uteri by the addition of arachidonic acid (5 mug/ml) or phospholipase A (160 mu./ml); the effects were abolished by indomethacin (20 mug/ml). However, the stimulation of uterine activity by PGF2alpha (30-60 ng/ml) was not affected by indomethacin. It is concluded that the release of prostaglandins from the pregnant rat uterus in vitro at term is related to the presence of viable foetuses.
Assuntos
Feto/fisiologia , Prenhez , Prostaglandinas/metabolismo , Útero/metabolismo , Animais , Ácidos Araquidônicos/farmacologia , Feminino , Técnicas In Vitro , Indometacina/farmacologia , Ligadura , Fosfolipases/farmacologia , Placenta , Gravidez , Antagonistas de Prostaglandina , Prostaglandinas F/metabolismo , Prostaglandinas F/farmacologia , Radioimunoensaio , Ratos , Estimulação Química , Fatores de Tempo , Contração Uterina/efeitos dos fármacos , Útero/cirurgiaRESUMO
Sinus node disease (SND) encompasses a number of abnormalities of sinus impulse generation and transmission within the atria and may lead to both bradyarrhythmias and tachycardias. Such abnormalities may be due to primary atrial electrophysiological abnormalities, or be secondary to drugs or abnormal autonomic control. The diagnosis may be readily established from the surface ECG or Holter recordings in many cases, but invasive electrophysiological study or assessment of the effects of autonomic blockade may be required in symptomatic patients in whom the diagnosis is suspected but not confirmed by simple electrocardiographic monitoring. Treatment should be restricted to those patients in whom clear correlation between symptoms and electrocardiographic or electrophysiological abnormalities has been established. Although a number of pharmacological agents have been assessed, the treatment of bradyarrhythmias should be permanent pacing. There is now substantial evidence that physiological (atrial or dual chamber) pacing reduces atrial arrhythmias, systemic embolisation, progression to heart failure and mortality, compared to single chamber ventricular pacing. Antiarrhythmic therapy may be required to control atrial tachyarrhythmias if they persist following pacing. In patients with uncontrolled atrial arrhythmias, especially those with ventricular pacemakers, long term oral anticoagulation should be considered to reduce the risk of systemic embolisation which is a common complication in patients with the bradycardia/tachycardia syndrome.
Assuntos
Estimulação Cardíaca Artificial/métodos , Bloqueio Sinoatrial , Antiarrítmicos/uso terapêutico , Eletrocardiografia , Humanos , Bloqueio Sinoatrial/diagnóstico , Bloqueio Sinoatrial/mortalidade , Bloqueio Sinoatrial/fisiopatologia , Bloqueio Sinoatrial/terapiaRESUMO
Isolated rat erythrocytes were labelled with [86Rb] as a tracer for intracellular K+. It was demonstrated that rat erythrocytes possess a Ca2+-mediated K+-efflux mechanism similar to that reported for human erythrocytes. This model was used to investigate the interactions of di- and tri-valent cations on potassium [86Rb] permeability in intact cells. Low concentrations of Ag2+ and Hg2+ haemolysed erythrocytes and Pb2+ produced a selective increase in [86Rb] efflux which became self-inhibitory at concentrations above 100 microM. The effects of Pb2+ were potentiated by A23187. Ni2+, Cu2+, Co2+, Zn2+, Fe2+, Mn2+, Y2+ and Ba2+ did not initiate [86Rb] efflux, even in the presence of 0.5 microM A23187 and at concentrations as high as 1 mM. All of these cations, except Ba2+, were potent inhibitors of [86Rb] efflux evoked by 50 microM Ca2+ + 0.5 microM A23187. The lanthanides Tb3+, Gd3+, Eu3+, Sm3+ and La3+ increased [86Rb] efflux at low concentrations in the presence of A23187, but were self inhibitory at higher concentrations. They also inhibited Ca2+-mediated [86Rb]-efflux. It is concluded that the effectiveness of a cation in activating [86Rb] efflux is, in part, related to its non-hydrated crystalline ionic radius, and that the site of activation may only accommodate ionic radii between 0.95 and 1.00 A.
Assuntos
Calcimicina/farmacologia , Cálcio/farmacologia , Eritrócitos/metabolismo , Potássio/sangue , Animais , Cobre/farmacologia , Chumbo/farmacologia , Masculino , Mercúrio/farmacologia , Metais Terras Raras/farmacologia , Ratos , Rubídio/sangue , Prata/farmacologia , Zinco/farmacologiaRESUMO
The effect of two subcutaneous injections of 0.6 mg nicotine, administered 40 min apart, was compared with placebo in four non-smoking subjects in a counter-balanced double-blind crossover design. The nicotine injections produced mean peak plasma nicotine concentrations of 5.3 ng/ml 10 min after the first injection and 8.5 ng/ml 10 min after the second injection. The nicotine injections produced an increase in mean dominant alpha frequency on the electroencephalogram (EEG) which was 2 Hz greater than the effect of placebo (P = 0.049) and also produced a heart-rate boost which was 8 beats per minute greater than that produced by placebo (P = 0.022). These effects on dominant alpha frequency and heart rate were most apparent in the 10 min following each nicotine injection. The increase in dominant alpha frequency found in non-smokers in this study was similar to that following nicotine inhalation in abstinent smokers in previous studies, and suggests that this is a primary effect of nicotine, rather than simply a reversal of withdrawal-induced EEG slowing.
Assuntos
Ritmo alfa/efeitos dos fármacos , Nicotina/farmacologia , Adulto , Afeto/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Injeções Subcutâneas , Masculino , Nicotina/administração & dosagem , Nicotina/sangue , Projetos Piloto , Desempenho Psicomotor/efeitos dos fármacosRESUMO
This study set out to investigate tolerance of the body water pool to short-term water deprivation in horses and, in particular, to assess whether feral horses from the Namib Desert showed tolerance to dehydration superior to Transvaal. Hydration status was compared in six feral horses from the Namib Desert and in six Boerperd farm horses under conditions of normal hydration and after 72 h of dehydration. Under normal hydration, the two groups did not differ significantly in water intake, plasma sodium and potassium concentrations, plasma osmolality, hematocrit, total plasma protein, body water content, or water turnover (ml.kg-0.82.day-1). The Namib horses were significantly smaller (P less than 0.0001) and turned over 5 liters less water per day than the Boerperd during normal hydration and 4 liters less during dehydration. Increases in plasma sodium concentration after 72 h of dehydration were greater (P less than 0.05) in the Namib horses. It was concluded that horses can easily tolerate water deprivation that results in a 12% reductions in body mass. The feral horses of the Namib desert were not significantly different per unit mass from domestic horses with regard to indexes of total body water content under conditions of normal hydration and after 72 h of dehydration. Their smaller size and, hence, lower water turnover might be mechanisms they use for survival in the Namib Desert.
Assuntos
Adaptação Fisiológica/fisiologia , Água Corporal/fisiologia , Homeostase/fisiologia , Animais , Proteínas Sanguíneas/metabolismo , Peso Corporal/fisiologia , Clima , Desidratação/sangue , Ingestão de Líquidos/fisiologia , Feminino , Hematócrito , Cavalos , Umidade , Masculino , Namíbia , Concentração Osmolar , Potássio/sangue , Sódio/sangue , TemperaturaRESUMO
The clinical and hemodynamic performance of the 19-mm Carpentier-Edwards supraannular aortic valve is largely unknown compared with that of the larger valves. Over 4 years we implanted the 19-mm Carpentier-Edwards supraannular aortic valve into 21 patients (20 female) with a mean age of 75 +/- 1.2 years (range, 59 to 86 years) and a mean body surface area of 1.6 +/- 0.03 m2 (range, 1.3 to 1.7 m2). There were four deaths, one operative and three late noncardiac deaths. Follow-up of the 17 survivors for a mean of 20 +/- 3.1 months (range, 2 to 42 months) demonstrated symptomatic improvement in all 17 (all are now in New York Heart Association functional class I or II). There were no valve-related complications and no patient required long-term anticoagulation. Doppler echocardiographic studies were used to assess the in vivo hemodynamic profile of the valve. Mean postoperative aortic valve gradient was 34.1 +/- 2.7 mm Hg (range, 19 to 52 mm Hg). Functional valve orifice area was 1.1 +/- 0.09 cm2 (range, 0.6 to 1.8 cm2). Mean cardiac output was 3.92 +/- 0.17 L/min (range, 3.2 to 5.1 L/min) with a mean cardiac index of 2.5 +/- 0.11 L.min-1 x m-2 (range, 2.1 to 3.2 L.min-1 x m-2). In conclusion, we have demonstrated that aortic valve replacement with the 19-mm Carpentier-Edwards supraannular aortic valve has a low operative mortality and offers major clinical benefits despite moderate transprosthetic gradients. This approach provides an alternative management strategy in elderly patients who would otherwise require low-profile mechanical valves or aortic root enlargement.