Marine macroalgae as sources of polyunsaturated fatty acids.

Algae from cold water (Canada) and warm water (China) were analysed for the total lipid content, and for their fatty acid (FA) composition and content. The major findings are that fatty acids (FA) from Canadian algae are generally richer in polyunsaturated FA (PUFA), with a higher n-3/n-6 FA ratio, and a higher degree of total unsaturation. The C 18:4 FA (stearidonic acid, morotic acid as synonym) was detected in greater amounts in cold water samples. The high levels of total PUFA, and especially of n-3 FA in Canadian algae, suggests possible utilization for nutritional purposes.

Marine macroalgae analyzed by mass spectrometry are rich sources of polyunsaturated fatty acids.

Algae from cold water (Canada) and warm water (China) were analyzed for their total lipid content, and for their fatty acid (FA) composition and content. The major findings are that FA from Canadian algae are generally richer in polyunsaturated FA (PUFA), with a higher n-3/n-6 FA ratio, and a higher degree of total unsaturation. The 18 C, 4 double bonds FA (18 : 4 stearidonic acid, morotic acid as synonym) was detected in greater amounts in cold water samples. The high levels of total PUFA, and especially of n-3 FA in Canadian algae, suggests their possible utilizations for nutritional purposes.

Tolerance of chronic hypercapnia by the European eel Anguilla anguilla.

European eels were exposed for 6 weeks to water CO(2) partial pressures (P(CO)(2)) from ambient (approx. 0.8 mmHg), through 15+/-1 mmHg and 30+/-1 mmHg to 45+/-1 mmHg in water with a total hardness of 240 mg l(-1) as CaCO(3), pH 8.2, at 23+/-1 degrees C. Arterial plasma P(CO)(2) equilibrated at approximately 2 mmHg above water P(CO)(2) in all groups, and plasma bicarbonate accumulated up to 72 mmol l(-1) in the group at a water P(CO)(2) of 45 mmHg. This was associated with an equimolar loss of plasma Cl(-), which declined to 71 mmol l(-1) at the highest water P(CO)(2). Despite this, extracellular acid-base compensation was incomplete; all hypercapnic groups tolerated chronic extracellular acidoses and reductions in arterial blood O(2) content (Ca(O)(2)), of progressive severity with increasing P(CO)(2). All hypercapnic eels, however, regulated the intracellular pH of heart and white muscle to the same levels as normocapnic animals. Hypercapnia had no effect on such indicators of stress as plasma catecholamine or cortisol levels, plasma osmolality or standard metabolic rate. Furthermore, although Ca(O)(2) was reduced by approximately 50% at the highest P(CO)(2), there was no effect of hypercapnia on the eels' tolerance of hypoxia, aerobic metabolic scope or sustained swimming performance. The results indicate that, at the levels tested, chronic hypercapnia was not a physiological stress for the eel, which can tolerate extracellular acidosis and extremely low Cl(-) levels while compensating tissue intracellular pH, and which can meet the O(2) requirements of routine and active metabolism despite profound hypoxaemia.

Fish as model in pharmacological and biological research.

Fish represent the oldest and most diverse classes of vertebrates, comprising around the 48% of the known member species in the subphylum Vertebrata. There are many scientific fields that use fish as models in research, including respiratory and cardiovascular research, cell culture, ecotoxicology, ageing, pharmacological and genetic studies.

Effects of plasma total ammonia content and pH on urea excretion in Nile tilapia.

Nile tilapia (Oreochromis niloticus) were infused with ammonium salts, acid, and base to investigate the effects of changes in arterial plasma total ammonia content (Tamm) and pH (pHa) on plasma urea-nitrogen (urea-N) levels and urea-N excretory fluxes (Jurea-N). The tilapia did not possess a functional hepatic ornithine urea-cycle (no significant carbamyl phosphate synthetase III activity). Infused substances were dissolved in a saline vehicle and injected twice (5 mL kg-1), the first infusion to "prime" the animal and promote a more marked response to the second infusion, given 2.5 h later. The results reported are those of the second infusion. Infusion of 200 mM NH4Cl increased Tamm, reduced pHa, and increased plasma urea-N and Jurea-N. Two hundred mM NH4HCO3 increased Tamm and arterial plasma total CO2 content (TaCO2), reduced pHa, and increased Jurea-N. Fifty mM HCl reduced pHa but had no effects on urea dynamics. Fifty mM NaOH increased pHa, plasma urea-N levels, and Jurea-N. Two hundred mM NaHCO3 increased pHa, TaCO2, plasma urea-N levels, and Jurea-N. Infusion of the saline vehicle was without effect. The results indicate that ammonia loading and plasma alkalosis both stimulate urea excretion in uricolytic fish. The responses to hyperammonemia or alkalosis were not modified when combined with elevated plasma bicarbonate levels.

Normal isoform of amyloid protein (PrP) in brains of spawning salmon.

The transmissible spongiform encephalopathies are a group of subacute progressive degenerative diseases of the nervous system which are always fatal in their outcome. These diseases appear to be caused by the abnormal isoform of the precursor protein of amyloid designated prion protein. The normal isoform has been identified in the tissues of all mammalian species thus far tested as well as in Drosophila. We report the presence of this protein for the first time in the brains of fish.

Dysthymia in neurological disorders.

Dysthymia is characterized by long-lasting periods of lowered mood. Epidemiological studies in the USA and Europe have demonstrated that the prevalence of dysthymia is at least 3% of the general population. Its pervasive occurrence makes dysthymia a public health problem worldwide. One feature of this disorder is its co-occurrence with medical and neurological disorders. A World Health Organization meeting on dysthymia in neurological disorders was held in Geneva, 1-3 July 1996 to address this topic. Some of the major goals of this meeting were to clarify the definition of dysthymia in the presence of neurological disorders and to evaluate current research in the field, to point out new areas for investigation, and to discuss current psychological and pharmacological treatments for dysthymia in neurological disorders. The potential roles of neuroendocrine and molecular mechanisms in dysthymia were identified through specific problems related to dysthymia occurring in disorders such as Parkinson's disease, Alzheimer's disease, stroke, multiple sclerosis and epilepsy. This meeting provided direction and opportunity for future studies in the under-recognized and under-investigated relationship between dysthymia and neurological disorders.

Cardiac performance in relation to oxygen supply varies with dietary lipid composition in sturgeon.

Dietary polyunsaturated fatty acids (PUFA) of the n-3 series that have beneficial effects on mammalian heart function are typically found at high levels in fish tissues. The effects of dietary fatty acid composition on cardiac function were investigated in the sturgeon. When compared with sturgeon maintained for 1 yr on a diet enriched with saturated fatty acids (SFA) (the coconut oil-supplemented diet, COD), sturgeon maintained on a diet enriched with n-3 PUFA (the fish oil-supplemented diet, FOD) had higher myocardial 20:5(n-3) and lower 20:4(n-6) content with a consequent decrease in the n-6-to-n-3 ratio (from 0.86 to 0.25) and a lower intrinsic in vitro heart rate (22.0 +/- 1.5 vs. 29.9 +/- 1.0 beats/min) and cardiac power output (PO) (0.33 +/- 0.08 vs. 0.48 +/- 0.03 mW/g), but had a greater in vitro scope for cardiac work (almost twice the maximal-to-basal PO ratio). Reducing the oxygen supply to the hearts significantly decreased, by approximately 40%, the maximal in vitro PO in the COD group of animals but had no effect in the FOD group. These differences in performance were not reflected in heart rate or blood pressure in vivo, either in normoxia or hypoxia. Addition of vitamin E as an antioxidant to the diets reduced intrinsic heart rate by approximately 25% but did not influence the effects (dietary fatty acid composition on in vitro cardiac performance. The results indicate that dietary n-3 PUFA can have beneficial effects on the resistance of the fish heart to environmental stressors such as hypoxia.

Aspects of cardioventilatory control in the adriatic sturgeon (Acipenser naccarii).

Cardioventilatory responses to hypoxia, the O2 chemoreceptor stimulant sodium cyanide (NaCN), and intra-arterial injection of atropine, noradrenaline and DL-propranolol were investigated in the adriatic sturgeon. Hypoxia elicited a bradycardia and hyperventilation. 1 mg NaCN added to water entering the buccal cavity stimulated a transient bradycardia but intra-arterial infusion of 150 micrograms NaCN did not, indicating that hypoxic bradycardia is controlled by chemoreceptors sensitive only to water O2 levels. NaCN stimulated hyperventilation both when added to the water and when infused intra-arterially, indicating that hypoxic hyperventilation is controlled by chemoreceptors sensitive to both internal and external milieux. Atropine abolished the hypoxic bradycardia and returned heart rate to normoxic values indicating that this species has no inhibitory vagal tone in normoxia. Noradrenaline stimulated ventilation, an effect abolished by DL-propranolol. Propranolol blocked ventilatory responses to intra-arterial infusion of NaCN whereas responses to NaCN added to the water remained unaffected, indicating that propranolol may inhibit internally-oriented O2-chemoreceptor activity or that ventilatory responses to intra-arterial NaCN are stimulated by a release of circulating catecholamines. Cardioventilatory control systems in sturgeon are similar to those of other actinopterygians but also show some characteristics of the system described for elasmobranchs.

Regional distribution of vasoactive intestinal peptide immunoreactivity in the brain of salmon, trout and carp.

The content of vasoactive intestinal peptide (VIP) was determined by radioimmunoassay in different brain regions of three fish species, namely salmon, trout and carp. The VIP extracted from salmon brain was shown by reverse-phase high-performance liquid chromatography to coelute with native porcine VIP. Highest VIP levels were measured in the salmon brain with a maximum of 112 pg/mg protein in the hypothalamus, followed by the telencephalon, olfactory bulb and optic tectum. In contrast, in the trout brain highest levels were found in the olfactory bulb (111 pg/mg protein). Lower levels were measured in the hypothalamus, telencephalon and cerebellum. The VIP content of the carp brain was considerably less, with highest values measured in the hypothalamus (12 pg/mg protein). The specificity in regional distribution further stresses the role of VIP in neurotransmission and indicates a function in neuroendocrine mechanisms and in the processing of olfactory stimuli.

Effects of diet on spontaneous locomotor activity and oxygen consumption in Adriatic sturgeon (Acipenser naccarii).

Adriatic sturgeon (Acipenser naccarii) were maintained on a commercial diet enriched either in long chain polyunsaturated fatty acids of the ω3 series (ω3 LCPUFA) or in saturated fatty acids (SFA). The effects of dietary fatty acid composition on spontaneous locomotor activity in normoxia and hypoxia (O2 tension = 10.5 ± 0.8 kPa), and on oxygen consumption (M(O) 2) in normoxia, in hypoxia (O2 tension = 6.6 ± 0.8 kPa) and during recovery were then investigated. The effects of adding supplementary vitamin E to the fat-enriched diets were also studied.Dietary fatty acid composition had effects on spontaneous locomotor activity and M(O) 2 in normoxia. Activity levels were higher in all sturgeon fed extra dietary fats (without vitamin E), when compared with control animals, but fish fed ω3 LCPUFA had a significantly lower M(O) 2 than those fed SFA, with intermediate M(O) 2 in controls. In hypoxia, sturgeon ω3 LCPUFA did not alter activity or M(O) 2 whereas those fed SFA reduced both and controls reduced M(O) 2. During recovery, both animals fed SFA and controls had a higher M(O) 2 than sturgeon fed ω3 LCPUFA. The data indicate that fish fed ω3 LCPUFA are more tolerant of hypoxia than controls or those fed SFA, as they did not reduce either activity or M(O) 2, and consumed less O2 during recovery.Vitamin E supplements modified the effects elicited by dietary fats. All sturgeon fed vitamin E had low activity levels in normoxia and hypoxia. Sturgeon fed vitamin E with ω3 LCPUFA had a higher M(O) 2 in normoxia than those fed ω3 LCPUFA alone; reduced M(O) 2 in hypoxia, and during recovery increased M(O) 2 to a rate higher than that of animals fed ω3 LCPUFA alone. In normoxia, sturgeon fed vitamin E with SFA had a similar M(O) 2 to those fed SFA alone but did not change M(O) 2 in hypoxia or during recovery. Thus, the effects of vitamin E were dependent on fat composition of the diet. Vitamin E with ω3 LCPUFA removed the beneficial effects on M(O) 2 and responses to hypoxia obtained with ω3 LCPUFA alone, but vitamin E with SFA allowed sturgeon to maintain aerobic metabolism in hypoxia, a more effective response than that observed in fish fed SFA alone.

Prevalence of headache and migrainous headache in Nigerian Africans: a community-based study.

In a door-to-door survey in a Nigerian town with stable population of about twenty thousand, 18,594 subjects were screened with a questionnaire, which involved a complete census, administered by non-doctor, including primary health care personnel. Migrainous headache was diagnosed on the basis of combination of responses to the questionnaire shown in a pilot study validated by neurological examination to have 92% sensitivity and 99% specificity. Crude life time prevalence ratio of at least one episode of headache unspecified was 51 percent (50% in males and 52% in females). The crude prevalence ratio of migrainous headache was 5.3 per 100 (5 per 100 in males and 5.6 per 100 in females), with peak age-specific prevalence ratios in the first decade in both males and females. Migrainous headache was three times as common in females as in males in the second and third decades. Prevalence of migrainous headache in Nigerian Africans appears less than in Caucasians. No social status was at special risk to developing migrainous headache.

Recommendations of the International Roundtable Workshop on Bovine Spongiform Encephalopathy.

Recommendations of the working party were summarized as follows: Determine the status in all countries of their national cattle herds with respect to BSE. Attempt to develop a test to recognize BSE-infected animals before they become clinically ill. Establish procedures to prevent spread of BSE agent into the cattle populations, especially by eliminating feeds containing rendered ruminant proteins. Review the rendering processes, identify the sources and destinations of rendered products, and suggest appropriate changes if needed. Especially needed are standardized rendering procedures in regard to use of organic solvents, temperature, and duration of heat treatment. Review import and export regulations to reduce the risk of spreading BSE and to maximize opportunities for safe trading in cattle and cattle products. The scrapie-free certification program of the USDA was supported, and similar programs might be considered by other countries. If BSE/scrapie is diagnosed in a given country, determine baseline incidence of CJD in those countries and consider contributing to an international registry. The WHO should address the problems of BSE, formulate policy, participate in and coordinate research, and provide training opportunities for veterinary and human health care workers from eastern European countries and developing nations. Government and private agencies should consider increasing support for research on transmissibility and pathogenesis of CJD, BSE, CWD, scrapie, and transmissible mink encephalopathy. Prepare and publish a critical neuropathologic review of all spongiform encephalopathies, naturally and experimentally transmitted, defining the characteristics of each disease in the various species known to be susceptible. Consider producing guidelines for the biological and pharmaceutical industries with regard to sourcing, collecting, and processing bovine and ovine materials.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk factors for febrile seizures in the People's Republic of China: a case control study.

A case control study was conducted to investigate the association of family history of febrile seizures (FS) and history of maternal, pregnancy and delivery, and postnatal factors with FS. Information was gathered by door-to-door survey in six major cities in the People's Republic of China. Factors present before the date of onset of FS were assessed in 182 subjects and in an equal number of controls matched for age, sex, and geographic area. The odds ratio for risk of FS in children with a family history of FS in a first-degree relative was 10.0 (confidence interval 2.7-58.6), confirming other observations that familial factors are an important predisposing characteristic for FS. Maternal acute respiratory infection during the first trimester of pregnancy was slightly more frequent in children with FS (odds ratio, 1.9 confidence interval 1.0-3.9). None of the other examined pregnancy or delivery factors was associated with an increased risk, suggesting that birth history is not an important factor predisposing to FS.