RESUMO
BACKGROUND: Long-chain omega-3 polyunsaturated fatty acids (LCn-3 PUFA) are essential nutrients and may be capable of delaying age-related cognitive decline. However, previous studies indicate that Australians are not meeting recommendations for LCn-3 PUFA intake. The current study therefore examined LCn-3 PUFA intake in an older Australia sample, as well as associations between LCn-3 PUFA intake and cognitive function. METHODS: Cross-sectional data were collected from 90 adults aged 50 to 80 years. LCn-3 PUFA intake was assessed using a food frequency questionnaire and red blood cell fatty acid profiles were used to calculate the Omega-3 Index (RBC n-3 index). Cognitive function was measured using Addenbrooke's Cognitive Examination-III. RESULTS: Positive associations were observed between age and RBC n-3 index (b=0.06, 95% CI: 0.01 - 0.10, P=0.01), and age and LCn-3 PUFA intake from fish oil capsules (b=17.5, 95% CI: 2.4 - 32.5 mg/day, P=0.02). When adjusting for LCn-3 PUFA from fish oil capsules, the association between age and RBC n-3 index was no longer significant. No associations were observed between LCn-3 PUFA intake and cognitive function. CONCLUSION: LCn-3 PUFA and fish oil consumption increased with age in this sample of older Australians, particularly due to supplement intake. However, LCn-3 PUFA intake was not associated with cognitive function.
Assuntos
Cognição/efeitos dos fármacos , Suplementos Nutricionais/normas , Ácidos Graxos Ômega-3/sangue , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Austrália , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e QuestionáriosRESUMO
BACKGROUND AND AIMS: Flow-mediated dilatation of the brachial artery (FMD) is a biomarker of endothelial function and cardiovascular health. Impaired FMD is associated with several cardiovascular risk factors including hypertension and obesity. Various food ingredients such as polyphenols have been shown to improve FMD. We investigated whether consuming resveratrol, a polyphenol found in red wine, can enhance FMD acutely and whether there is a dose-response relationship for this effect. METHODS AND RESULTS: 19 overweight/obese (BMI 25-35 kg m(-2)) men or post-menopausal women with untreated borderline hypertension (systolic BP: 130-160 mmHg or diastolic BP: 85-100 mmHg) consumed three doses of resveratrol (resVida™ 30, 90 and 270 mg) and a placebo at weekly intervals in a double-blind, randomized crossover comparison. One hour after consumption of the supplement, plasma resveratrol and FMD were measured. Data were analyzed by linear regression versus log(10) dose of resveratrol. 14 men and 5 women (age 55 ± 2 years, BMI 28.7 ± 0.5 kg m(-2), BP 141 ± 2/89 ± 1 mmHg) completed this study. There was a significant dose effect of resveratrol on plasma resveratrol concentration (P < 0.001) and on FMD (P < 0.01), which increased from 4.1 ± 0.8% (placebo) to 7.7 ± 1.5% after 270 mg resveratrol. FMD was also linearly related to log(10) plasma resveratrol concentration (P < 0.01). CONCLUSION: Acute resveratrol consumption increased plasma resveratrol concentrations and FMD in a dose-related manner. This effect may contribute to the purported cardiovascular health benefits of grapes and red wine.
Assuntos
Hipertensão/fisiopatologia , Obesidade/fisiopatologia , Sobrepeso/fisiopatologia , Estilbenos/administração & dosagem , Vasodilatação/efeitos dos fármacos , Artéria Braquial , Doenças Cardiovasculares/prevenção & controle , Estudos Cross-Over , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Método Duplo-Cego , Endotélio Vascular/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Placebos , Resveratrol , Fatores de Risco , Estilbenos/sangueRESUMO
Consumption of flavanol-containing cocoa products has been shown to lower blood pressure (BP), but the minimum dose required to reduce BP is not known. This study aimed to examine the effect of three different doses of cocoa flavanols (CF) on 24-h mean arterial BP. Twenty four hour ambulatory BP (24-ABP) monitoring was performed in 32 men and 20 postmenopausal women with untreated mild hypertension (seated clinic BP >130/85 and <160/100 mm Hg). Participants were randomized and instructed to consume daily a reconstituted cocoa beverage containing 33, 372, 712 or 1052 mg day(-1) of CF for 6 weeks in a double-blind, parallel comparison. Seated clinic BP and 24-h ABP were measured at 0, 3 and 6 weeks. Seated clinic BP did not change during the study period. There were significant reductions in 24-h systolic (5.3+/-5.1 mm Hg; P=0.001), diastolic (3+/-3.2 mm Hg; P=0.002) and mean arterial BP (3.8+/-3.2 mm Hg; P=0.0004) at the 1052 mg day(-1) CF only. No reduction in BP was seen at any other dose. No evidence of dose-response was seen in this experiment. The highest dose of 1052 mg CF per day was found to significantly lower BP. These results support previous evidence for CF to lower BP, however more research is needed to establish the most effective dose and food matrix.
Assuntos
Pressão Sanguínea/efeitos dos fármacos , Cacau , Flavonóis/administração & dosagem , Hipertensão/tratamento farmacológico , Fitoterapia , Adulto , Idoso , Monitorização Ambulatorial da Pressão Arterial , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Hipertensão/dietoterapia , Masculino , Pessoa de Meia-Idade , Extratos Vegetais/administração & dosagemRESUMO
Animal studies suggest that increased consumption of the long-chain omega-3 polyunsaturated fatty acids, eicosapentaenoic acid and docosahexaenoic acid, can protect against the development of obesity in animals exposed to an obesogenic diet and reduce body fat when already obese. There is also evidence that increased intakes of these fatty acids can reduce body fat in humans, but human studies are relatively few and have generally been conducted over short time periods with small sample sizes, making it difficult to draw definitive conclusions. Reported reductions in body fat may result from appetite-suppressing effects, adipocyte apoptosis and changes of gene expression in skeletal muscle, heart, liver, intestine and adipose tissues that suppress fat deposition and increase fat oxidation and energy expenditure. We conclude that increased intakes of long-chain omega-3 fatty acids may improve body composition, but longer-term human studies are needed to confirm efficacy and determine whether increasing omega-3 intakes might be an effective strategy to combat obesity.
Assuntos
Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Ácidos Graxos Ômega-3/administração & dosagem , Obesidade/prevenção & controle , Animais , Apoptose/efeitos dos fármacos , Composição Corporal/efeitos dos fármacos , Dieta Redutora , Modelos Animais de Doenças , Metabolismo Energético/efeitos dos fármacos , Medicina Baseada em Evidências , Ácidos Graxos Ômega-3/farmacologia , HumanosRESUMO
This study examined the effect of supplementation with concentrated bovine colostrum protein powder (intact) on plasma insulin-like growth factor I (IGF-I) concentrations, endurance running performance and recovery. Thirty physically active males completed 8 weeks of running training whilst consuming 60 g x day(-1) of intact powder (n=17) or a concentrated whey protein powder placebo (n=13) in a randomised, double-blind, parallel design. Plasma IGF-I concentrations were measured prior to subjects performing two (approximately 30 min) incremental treadmill running tests to exhaustion (RUN1 and RUN2) separated by 20 min of passive recovery at Weeks 0. 4 and 8. Plasma IGF-I concentrations showed little change in either group (p=0.83). Effective peak running speed (PRSE; i.e. equivalent of peak power) during RUN1 was not different between groups at Week 0 (p>0.99), and had increased by a similar amount in both groups by Week 4 (mean+/-SD, intact 2.2+/-4.0%, placebo 3.2+/-3.3%; 95% confidence interval [95% CI 15.7 to -13.7%; p=0.89) and Week 8 (intact 3.6+/-5.6%, placebo 3.4+/-4.4 %; 95% CI -100.0 to 100.0%; p>0.99). PRSE was less in both groups during RUN2 (p<0.05), but was not significantly different between groups at Week 0 (p>0.99). PRSE during RUN2 tended to have increased more in the placebo group by Week 4 (intact 1.8+/-4.8%, placebo 4.2+/-3.9%; 95% CI 0.2 to -5 0%; p=0.07), but the intact group had increased PRSE significantly more by Week 8 (intact 4.6+/-6.1%, placebo 2.0+/-4.5%; 95% Cl 0.0 to 5.2%; p=0.05). resulting in a significantly faster PRSE (p=0.003). We conclude that supplementation with intact powder did not increase plasma IGF-I concentrations or improve performance during an initial bout of incremental running to exhaustion in our sample. However, performance during a second bout of exercise may be improved by as much as 5.2% in the average subject after 8 weeks of supplementation, possibly due to an enhancement of recovery.
Assuntos
Colostro , Suplementos Nutricionais , Fator de Crescimento Insulin-Like I/análise , Resistência Física , Corrida , Adolescente , Adulto , Proteínas Alimentares , Método Duplo-Cego , Humanos , Masculino , Análise e Desempenho de TarefasRESUMO
BACKGROUND: This review article examines the role of the different types of neck dissection in the treatment of squamous carcinoma metastases to the cervical nodes. METHODS: A critical evaluation of the literature on the pathologic basis, oncologic effectiveness, and functional outcome of neck dissection. RESULTS: Pathologic data show preferential metastasis to different lymph node levels, in N0- and N+-staged disease, depending on the primary tumor site. Comparative studies on control of regional metastases suggest that modified radical is no less effective than radical neck dissection, but there is insufficient data to draw firm conclusions on the role of selective neck dissection. Selective and modified radical dissections result in less shoulder disability than radical neck dissection. CONCLUSIONS: Modified radical neck dissection is supported by pathologic and clinical evidence in N1- and 2-staged disease. There may be a role for selective dissection, but there is a need for more information on oncologic outcome. Prospective multicenter systematic data collection on the outcome of neck dissection is a pragmatic alternative to a trial.
Assuntos
Carcinoma de Células Escamosas/patologia , Neoplasias de Cabeça e Pescoço/patologia , Excisão de Linfonodo , Humanos , Excisão de Linfonodo/métodos , Metástase Linfática , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Qualidade de Vida , Resultado do TratamentoRESUMO
There is little information available regarding epidemiologic risk factors for Langerhans cell histiocytosis (LCH). An exploratory investigation was conducted using information obtained from parents of 177 cases of LCH diagnosed before 21 years of age (median 2 years). Utilizing data available from the Children's Cancer Group, LCH cases were compared to two matched control groups including 614 patients diagnosed with a variety of childhood cancers and 318 community controls. Questionnaire data included information on demographics, prenatal and perinatal factors, complications in the neonatal period, environmental exposures, family medical history, and childhood exposures. Factors found to be statistically significantly associated with an increased risk of LCH included: maternal urinary tract infection during the index pregnancy, feeding problems during infancy, and blood transfusions during infancy. Use of supplemental vitamins was associated with a significantly decreased risk of LCH. Results from this exploratory study provide a basis for speculation on potential etiologic risk factors for LCH. Future epidemiologic investigations of LCH need to consider the presenting disease characteristics in assessing possible etiologic factors.
Assuntos
Histiocitose de Células de Langerhans/epidemiologia , Adolescente , Estudos de Casos e Controles , Criança , Pré-Escolar , Exposição Ambiental , Saúde da Família , Feminino , Histiocitose de Células de Langerhans/etiologia , Humanos , Lactente , Masculino , Análise Multivariada , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Fatores de Risco , Fatores Socioeconômicos , Estados Unidos/epidemiologiaRESUMO
BACKGROUND & AIMS: The relative sensitivities of barium enema and colonoscopy for colorectal cancer are still debated. The aim of this study was to determine the relative sensitivity of barium enema and colonoscopy in general clinical practice. METHODS: Medical records of 2193 consecutive colorectal cancer cases identified in 20 central Indiana hospitals were reviewed. All procedures performed within 3 years of the diagnosis were identified. RESULTS: The sensitivity of colonoscopy for colorectal cancer (95%) was greater than that for barium enema (82.9%), with an odds ratio of 3.93 for a missed cancer by barium enema compared with colonoscopy. The sensitivity of double-contrast barium enema (85.2%) was not different from that of single-contrast (81.8%). Barium enema performed no better in the right than the left colon. Cancers detected by colonoscopy were more likely to be Dukes' class A (24.9%) than cancers detected by barium enema (9.8%). Colonoscopy performed by gastroenterologists was more sensitive (97.3%) for cancer than colonoscopy by nongastroenterologists (87%), with an odds ratio of 5.36 for a missed cancer by a nongastroenterologist compared with a gastroenterologist. CONCLUSIONS: Hospital quality assurance committees and/or third-party payors should review the sensitivity of barium enema and colonoscopy by practitioners in their institutions. Corrective measures are recommended when sensitivity deviates significantly below the standard set by gastroenterologists performing colonoscopy in this study.
Assuntos
Sulfato de Bário , Colonoscopia , Neoplasias Colorretais/diagnóstico , Enema , Neoplasias Colorretais/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Radiografia , Sensibilidade e EspecificidadeRESUMO
The effect of feeding supra-nutritional levels of α-tocopheryl acetate on its deposition in two porcine muscles of different metabolic rates (m. longissimus dorsi and m. psoas major) and the effect on meat quality (lipid oxidation, colour stability and drip loss) was studied. Pigs were fed a standard diet supplemented with three levels: 100, 200 and 700 mg/kg of α-tocopheryl acetate from the time of weaning to slaughter at 90kg live weight. Muscle α-tocopherol levels were linearly related to the logarithm of dietary α-tocopheryl acetate supplementation and the linear relationship was estimated for the two muscles. The levels of α-tocopherol in the two muscles differed by a parallel displacement with consistently higher α-tocopherol levels in m. psoas major compared to m. longissimus dorsi. Dietary α-tocopheryl acetate supplementation significantly reduced lipid oxidation as measured by thiobarbituric acid reactive substances (TBARS) in both raw and cooked meat during storage at 4 °C for 6 days. Drip loss and colour stability of raw muscles were not affected by dietary α-tocopheryl acetate levels, 100mg α-tocopheryl acetate/ kg feed resulted in sufficient α-tocopherol levels in muscles to ensure minimum drip loss and optimum colour stability.
RESUMO
N-nitroso compounds and their precursors, nitrites and nitrates, have been hypothesized as risk factors, and vitamins C and E, which inhibit N-nitroso formation, as protective factors for brain tumors. A case-control study of maternal diet during pregnancy and risk of astrocytoma, the most common childhood brain tumor, was conducted by the Childrens Cancer Group. The study included 155 cases under age six at diagnosis and the same number of matched controls selected by random-digit dialing. A trend was observed for consumption of cured meats, which contain preformed nitrosamines (a class of N-nitroso compounds) and their precursors (adjusted odds ratio [OR] for highest quartile of intake relative to lowest = 1.7, P trend = 0.10). However, no strong trends were observed for nitrosamine (OR = 0.8, P = 0.60); nitrite (OR = 1.3, P = 0.54); nitrate (OR = 0.7, P = 0.43); vitamin C (OR = 0.7, P = 0.37); or vitamin E (OR = 0.7, P = 0.48). Iron supplements were associated with a significant decrease in risk (OR = 0.5, 95 percent confidence interval = 0.3-0.8). The effect of several dietary factors differed by income level, making interpretation of the results difficult. Future research should investigate the effect of dietary components not assessed in this study, as these may explain the disparate effects by income level. The results of this study provide limited support for the nitrosamine hypothesis.
Assuntos
Astrocitoma/epidemiologia , Neoplasias Encefálicas/epidemiologia , Dieta , Gravidez , Canadá/epidemiologia , Carotenoides/administração & dosagem , Pré-Escolar , Feminino , Humanos , Renda , Ferro/administração & dosagem , Carne , Tumores Neuroectodérmicos Primitivos/epidemiologia , Compostos Nitrosos/administração & dosagem , Fatores de Risco , Estados Unidos/epidemiologia , Vitamina A/administração & dosagem , Vitamina E/administração & dosagem , beta CarotenoRESUMO
BACKGROUND: It has been hypothesized that a high dietary intake of nitrosamines and their precursors, nitrites and nitrates, is a risk factor for brain tumors. Vitamins C and E inhibit the formation of nitrosamines and thus may be protective. METHODS: We conducted a case-control study of maternal diet and the risk of primitive neuroectodermal tumors of the brain in children. The case patients were under the age of six years at diagnosis in 1986 to 1989. The controls were selected by random-digit telephone dialing and were matched for age and race to 166 case patients. Telephone interviews with the mothers included questions on the frequency of consumption of alcohol, vitamin and mineral supplements, and 53 foods during pregnancy. RESULTS: Significant protective trends were observed for vegetables (odds ratio for the highest quartile group for intake relative to the lowest, 0.37; P for trend = 0.005), fruits and fruit juices (odds ratio, 0.28; P = 0.003), vitamin A (odds ratio, 0.59; P = 0.03), vitamin C (odds ratio, 0.42; P = 0.009), nitrate (odds ratio, 0.44; P = 0.002), and folate (odds ratio, 0.38; P = 0.005). A nonsignificant trend of increasing risk was observed for nitrosamine (odds ratio, 1.65; P = 0.15). The use of iron (odds ratio, 0.43; P = 0.004), calcium (odds ratio, 0.42; P = 0.05), and vitamin C (odds ratio, 0.35; P = 0.04) supplements at any time during the pregnancy and the use of multivitamins during the first six weeks (odds ratio, 0.56; P = 0.02) were associated with decreased risk. In multivariate analyses, folate, early multivitamin use, and iron supplements generally remained protective. CONCLUSIONS: These results do not support the hypothesis that nitrosamines have a role in the development of primitive neuroectodermal tumors in young children, but they do suggest that certain other aspects of maternal diet can influence the risk.
Assuntos
Neoplasias Encefálicas/etiologia , Dieta , Efeitos Tardios da Exposição Pré-Natal , Astrocitoma/etiologia , Estudos de Casos e Controles , Pré-Escolar , Dieta/estatística & dados numéricos , Feminino , Alimentos , Humanos , Masculino , Nitrosaminas/administração & dosagem , Gravidez , Cuidado Pré-Natal/estatística & dados numéricos , Fatores de Risco , Vitaminas/administração & dosagemRESUMO
We report our experience of submucous resection of the nasal septum under local anaesthesia as an outpatient procedure. We have audited 50 consecutive cases and compared the results with a similar group of patients in whom the operation was carried out in the usual way under general anaesthesia. We have found the procedure to be safe, effective and economically advantageous.
Assuntos
Procedimentos Cirúrgicos Ambulatórios , Mucosa Nasal/cirurgia , Septo Nasal/cirurgia , Adolescente , Adulto , Idoso , Procedimentos Cirúrgicos Ambulatórios/economia , Anestesia Geral , Anestesia Local , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologiaRESUMO
A new technique for tympanocentesis and grommet insertion using local anesthetic is described. Its routine application in suitable patients will greatly simplify the management of ventilation tube insertion in the modern health care system.
Assuntos
Anestesia Local , Ventilação da Orelha Média , Anestésicos Locais , Combinação de Medicamentos , Humanos , Lidocaína , Combinação Lidocaína e Prilocaína , PrilocaínaRESUMO
The Childrens Cancer Study Group conducted a case-control study of occupational exposures of parents of 204 children (under 18 yr of age) with acute nonlymphoblastic leukemia. The most consistent finding was an association of acute nonlymphoblastic leukemia risk with pesticide exposure. Controls matched by date of birth and race were obtained through random digit dialing. Odds ratio (OR) for paternal pesticide exposure in jobs held for longer than 1000 days was 2.7 (95% confidence interval, 1.0 to 7.0; trend, P = 0.06), and seven case mothers and no control mothers had prolonged exposure (trend, P = 0.008). Risk estimates for parental pesticide exposure were substantially increased for children under age 6 at diagnosis (OR for prolonged exposure to either parent = 11.4; trend, P = 0.003) and for those with myelomonocytic and monocytic subtypes (OR, 13.6; trend, P = 0.007). Moreover, there were significantly elevated risks for direct exposure of the child to pesticides in the household (OR for exposure most days = 3.5; trend, P = 0.04) and for maternal exposure to household pesticides at the time of pregnancy (eight case mothers versus no controls for exposure most days; trend, P = 0.05). Paternal exposures to solvents (OR, 2.1; P = 0.003) and petroleum products (OR, 2.4; P = 0.002) were reported more commonly for cases than controls. Other occupational exposures reported significantly more often by case parents were paternal exposure to plastics or lead and maternal exposure to paints and pigments, metal dusts, and sawdust. These data provide further evidence for a role of occupational risk factors in the etiology of childhood cancer.
Assuntos
Exposição Ambiental , Leucemia Mieloide Aguda/etiologia , Pais , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Poeira , Feminino , Humanos , Lactente , Chumbo , Masculino , Praguicidas , Petróleo , Plásticos , Probabilidade , Análise de Regressão , Fatores Socioeconômicos , Solventes , Estados UnidosRESUMO
Forty-six patients requiring arthroscopic surgery following diagnostic arthroscopy under local anaesthetic infiltration had this tried under the same anaesthetic (four patients had to be converted to a general anaesthetic to complete the procedure). Local infiltration provides good anaesthesia for arthroscopic surgery, except in those with an acutely locked knee or a painful collateral ligament.
Assuntos
Anestesia Local , Artroscopia , Joelho/cirurgia , Prilocaína , Adolescente , Adulto , Idoso , Humanos , Pessoa de Meia-IdadeRESUMO
Sixty patients underwent arthroscopy of the knee as day cases using a local anaesthetic technique. This provided satisfactory operating conditions and high patient acceptability.
Assuntos
Anestesia Local , Artroscopia , Articulação do Joelho/cirurgia , Procedimentos Cirúrgicos Ambulatórios , HumanosRESUMO
Blood loss in periodontal flap surgery using lidocaine 2% with either 1:50,000 or 1:100,000 epinephrine was compared. Ten patients from the graduate periodontal clinic were selected for the study. After the initial therapy which included oral hygiene instruction, scaling and root planning and occlusal adjustment, 20 surgical procedures were performed. In any one patient if 1:50,000 epinephrine was used on the posterior sextant of an arch, then 1:100,000 epinephrine was used on the contralateral side, with similar volumes being injected by the same method. Blood loss was determined by the cyanmethemoglobin comparison technique. Procedures using lidocaine 2% with 1:100,000 epinephrine generally had more than twice as much blood loss as those using lidocaine 2% with 1:50,000 epinephrine.
Assuntos
Anestesia Dentária , Anestesia Local , Epinefrina/administração & dosagem , Periodonto/cirurgia , Avaliação de Medicamentos , Hemorragia Gengival/diagnóstico , Hemorragia Gengival/prevenção & controle , Humanos , Lidocaína , Bolsa Periodontal/cirurgia , Retalhos CirúrgicosRESUMO
The present study was designed to investigate the role of the central nervous system in the rebound hypertension precipitated by abrupt cessation of chronic clonidine (Cl) treatment. Male Wistar rats were treated with Cl (100 micrograms/kg, s.c.) twice daily for 7 days. Systolic blood pressure and heart rate were measured at different time intervals during Cl treatment. Rebound hypertension occurred 16-18 h after the last injection of Cl, but not in control animals given saline (0.1 ml) twice a day for 7 days. Rats were anesthetized with ether during this rebound phase of Cl withdrawal, an electrode inserted into the posterior hypothalamus, and a cannula introduced into the lateral cerebral ventricle. The posterior hypothalamus was electrically stimulated, and voltage-response curves obtained for control and Cl-treated rats revealed that the pressor responsiveness to hypothalamic stimulation was significantly potentiated in the Cl-treated rats. In addition, the depressor response to a single injection of Cl (10 micrograms) into the lateral cerebral ventricle was significantly attenuated in the Cl-treated rats. Additional experiments were performed in pithed rats to determine the involvement of peripheral adrenergic mechanisms in the rebound hypertension. When rats were pithed during the hypertensive phase of withdrawal, the blood pressure of treated rats decreased to a level which was similar to that of control animals. While the pressor responses to total spinal stimulation were similar in both the groups, the effect of exogenous norepinephrine was significantly attenuated in Cl-treated rats., These results suggest that a hyperresponsiveness of central noradrenergic pressor pathways contributes to the rebound hypertension noted following the abrupt cessation of clonidine treatment.
Assuntos
Encéfalo/fisiologia , Clonidina/farmacologia , Hipertensão/fisiopatologia , Norepinefrina/fisiologia , Síndrome de Abstinência a Substâncias/fisiopatologia , Sistema Nervoso Simpático/fisiologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Estimulação Elétrica , Frequência Cardíaca/efeitos dos fármacos , Humanos , Hipotálamo/fisiologia , Ratos , Transmissão Sináptica/efeitos dos fármacosRESUMO
The availability of essential fatty acids in fish neutral lipid to tissue phospholipids was determined under conditions of adequate and inadequate essential fatty acid intake as well as during fasting. Juvenile rainbow trout were fed a semi-purified diet containing varying levels of cod liver oil, with or without supplementary olein. Fatty acid analysis indicated that in all treatments the neutral lipid pool was not turned over during feeding but was enhanced by exogenous or endogenously synthesized fatty acids. Fish that received diets devoid of essential fatty acids maintained virtually all of the docosahexenoic acid originally present in each lipid pool. Fish fed diets containing essential fatty acids deposited them in proportion to the dietary levels. After a 4-week fast, no change was noted in the relative levels of fatty acids in neutral lipid indicating that all fatty acids in neutral lipid were catabolized equally--including essential fatty acids. During fasting there was a selective retention of docosahexenoic and linoleic acids in the phospholipid pool.