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PubMed2003

Global pollution monitoring of PCBs and organochlorine pesticides using skipjack tuna as a bioindicator.

Concentrations of organochlorines (OCs) representing persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), hexachlorocyclohexane isomers (HCHs), and hexachlorobenzene (HCB), were determined in the liver of skipjack tuna (Katsuwonus pelamis) collected from the offshore waters of various regions in the world (offshore waters around Japan, Taiwan, Philippines, Indonesia, Seychelles, and Brazil, and the Japan Sea, the East China Sea, the South China Sea, the Bay of Bengal, and the North Pacific Ocean). OCs were detected in livers of all of the skipjack tuna collected from the locations surveyed, supporting the thesis that there is widespread contamination of persistent OCs in the marine environment. Within a location, no significant relationship between growth-stage (body length and weight) and OC concentrations (lipid weight basis) was observed, and the OC residue levels were rather uniform among the individuals. Interestingly, the distribution of OC concentrations in skipjack tuna was similar to those in surface seawaters from which they were taken. These results suggest that OC concentrations in skipjack tuna could reflect the pollution levels in seawater from which they are collected and that this species is a suitable bioindicator for monitoring the global distribution of OCs in offshore waters and the open ocean. Concentrations of PCBs and CHLs in skipjack tuna were higher in offshore waters around Japan (up to 1100 and 250 ng/g lipid wt, respectively), suggesting the presence of sources of PCBs and CHLs in Japan. High concentrations of DDTs and HCHs were observed in samples from the Japan Sea, the East China Sea, the South China Sea, and the Bay of Bengal (up to 1300 and 22 ng/g lipid wt, respectively). This result suggests recent use of technical DDT and HCH for agricultural and/or public health purposes in Russia, China, India, and some other developing Asian countries. Relatively high concentrations of PCBs, CHLs, HCHs, and HCB were also observed in samples collected from some locations in the middle of the Pacific Ocean, indicating the expansion of OC contamination on a global scale. Considering these facts, continuous studies monitoring these compounds in offshore waters and the open seas, using skipjack tuna as a bioindicator, are needed to further understand the future trend of contamination.

Animals↗
PubMed2005

Genetic diversity and historical demography of Atlantic bigeye tuna (Thunnus obesus).

Bigeye (Thunnus obesus) is a large, pelagic, and migratory species of tuna that inhabits tropical and temperate marine waters worldwide. Previous studies based on mitochondrial RFLP data have shown that bigeye tunas from the Atlantic Ocean are the most interesting from a genetic point of view. Two highly divergent mitochondrial haplotype clades (I and II) coexist in the Atlantic Ocean. One is almost exclusive of the Atlantic Ocean whereas the other is also found in the Indo-Pacific Ocean. Bigeye tuna from the Atlantic Ocean is currently managed as a single stock, although this assumption remains untested at the genetic level. Therefore, genetic diversity was determined at the mitochondrial control region to test the null hypothesis of no population structure in bigeye tuna from the Atlantic Ocean. A total of 331 specimens were sampled from four locations in the Atlantic Ocean (Canada, Azores, Canary Islands, and Gulf of Guinea), and one in the Indian and Pacific Oceans, respectively. The reconstructed neighbor-joining phylogeny confirmed the presence of Clades I and II throughout the Atlantic Ocean. No apparent latitudinal gradient of the proportions of both clades in the different collection sites was observed. Hierarchical AMOVA tests and pairwise phi(ST) comparisons involving Atlantic Ocean Clades I and II were consistent with a single stock of bigeye tuna in the Atlantic Ocean. Population genetic analyses considering phylogroups independently supported gene flow within Clade II throughout the Atlantic Ocean, and within Clade I between Atlantic and Indo-Pacific Oceans. The latter result suggests present uni-directional gene flow from the Indo-Pacific into the Atlantic Ocean. Moreover, mismatch analyses dated divergence of Clades I and II during the Pleistocene, as previously proposed. In addition, migration rates were estimated using coalescent methods, and showed a net migration from Atlantic Ocean feeding grounds towards the Gulf of Guinea, the best-known spawning ground of Atlantic bigeye tuna.

Animals↗
PubMed2001

Dynamics of ANS binding to tuna apomyoglobin measured with fluorescence correlation spectroscopy.

The dynamics of the binding reaction of ANS to native and partly folded (molten globule) tuna and horse apomyoglobins has been investigated by fluorescence correlation spectroscopy and frequency domain fluorometry. The reaction rate has been measured as a function of apomyoglobin and ANS concentrations, pH, and temperature. Examination of the autocorrelation functions shows that the reaction rate is fast enough to be observed in tuna apomyoglobin, whereas the reaction rate in horse apomyoglobin is on the same time scale as diffusion through the volume or longer. Specifically, for tuna apomyoglobin at pH 7 and room temperature the on rate is 2200 microM(-1) s(-1) and the off rate is 5900 s(-1), in comparison with k(on) = 640 microM(-1) s(-1) and k(off) = 560 s(-1) for horse myoglobin as measured previously. The independence of the reaction rate from the ANS concentration indicates that the reaction rate is dominated by the off rate. The temperature dependence of the on-rate shows that this rate is diffusion limited. The temperature dependence of the off rates analyzed by Arrhenius and Ferry models indicates that the off rate depends on the dynamics of the protein. The differences between horse and tuna apomyoglobins in the ANS binding rate can be explained in terms of the three-dimensional apoprotein structures obtained by energy minimization after heme removal starting from crystallographic coordinates. The comparison of the calculated apomyoglobin surfaces shows a 15% smaller cavity for tuna apomyoglobin. Furthermore, a negative charge (D44) is present in the heme cavity of tuna apomyoglobin that could decrease the strength of ANS binding. At pH 5 the fluorescence lifetime distribution of ANS-apomyoglobin is bimodal, suggesting the presence of an additional binding site in the protein. The binding rates determined by FCS under these conditions show that the protein is either in the open configuration or is more flexible, making it much easier to bind. At pH 3, the protein is in a partially denatured state with multiple potential binding sites for ANS molecule, and the interpretation of the autocorrelation function is not possible by simple models. This conclusion is consistent with the broad distribution of ANS fluorescence lifetimes observed in frequency domain measurements.

Anilino Naphthalenesulfonates↗
PubMed1997

Simulation of large-scale tropical tuna movements in relation with daily remote sensing data: the artificial life approach.

Tunas are known to be able to travel long distances. The aim of this paper is to propose new ethological models which reproduce some tuna movements using the dynamics of their environment. We use sea surface temperature animations (from remote sensing data) to model the South West Indian Ocean, and French purse seiners data are used to estimate movements of fish. The objective of the models will be to find a northern movement from the Mozambique Channel to the Seychelles Islands at the appropriate time (May-July). The initial model uses our ecological knowledge of tunas, i.e. the search behavior for high concentrations of food commonly associated with thermal fronts. In some cases, this simple model creates some northern movements from the Mozambique Channel, but it cannot be used to reproduce large-scale movements between the Mozambique Channel and the Seychelles Islands. The next generation model is created where tuna behaviors are modeled by an artificial neural network, using a genetic algorithm to adjust the connection weights. The tuna school-network receives daily information from its local environment and chooses the best actions in order to be able to pass from the Mozambique Channel to the Seychelles Islands at the appropriate time. One neural network emerges and represents an adaptive behavior able to interpret daily sea surface temperatures to mimic large-scale tuna movements. This artificial behavior can be generalized to each possible departure position from the Mozambique Channel. This modelling represents a new tool to study large-scale movements of pelagic fish, and is a first step towards real-time management of fisheries.

Algorithms↗
PubMed2002

Structure and function of tuna tail tendons.

The caudal tendons in tunas and other scombrid fish link myotomal muscle directly to the caudal fin rays, and thus serve to transfer muscle power to the hydrofoil-like tail during swimming. These robust collagenous tendons have structural and mechanical similarity to tendons found in other vertebrates, notably the leg tendons of terrestrial mammals. Biochemical studies indicate that tuna tendon collagen is composed of the (alpha1)(2),alpha2 heterotrimer that is typical of vertebrate Type I collagen, while tuna skin collagen has the unusual alpha1,alpha2,alpha3 trimer previously described in the skin of some other teleost species. Tuna collagen, like that of other fish, has high solubility due to the presence of an acid-labile intermolecular cross-link. Unlike collagen in mammalian tendons, no differences related to cross-link maturation were detected among tendons in tuna ranging from 0.05 to 72 kg (approx. 0.25-6 years). Tendons excised post-mortem were subjected to load cycling to determine the modulus of elasticity and resilience (mean of 1.3 GPa and 90%, respectively). These material properties compare closely to those of leg tendons from adult mammals that can function as effective biological springs in terrestrial locomotion, but the breaking strength is substantially lower. Peak tendon forces recorded during steady swimming appear to impose strains of much less than 1% of tendon length, and no more than 1.5% during bursts. Thus, the caudal tendons in tunas do not appear to function as elastic storage elements, even at maximal swimming effort.

Aging↗
PubMed1999

Comparison of natural polyphenol antioxidants from extra virgin olive oil with synthetic antioxidants in tuna lipids during thermal oxidation.

Polyphenols extracted from extra virgin olive oil (EVOO) were tested for their ability to inhibit lipid oxidation of canned tuna. Hydroperoxide formation during oxidation was monitored by measurement of peroxide value and decomposition of hydroperoxides by static headspace gas chromatographic analysis of volatiles. In tuna oxidized at 40 and 100 degrees C, 400 ppm of the EVOO polyphenols was an effective antioxidant as compared with 100 ppm of a 1:1 mixture of the synthetic antioxidants butylated hydroxytoluene and butylated hydroxyanisole. However, at concentrations <100 ppm, the EVOO phenolic compounds promoted hydroperoxide formation and decomposition. The EVOO polyphenols were effective antioxidants when added to heated tuna muscle in the presence of either brine or refined olive oil. The oxidation rate in tuna muscle packed in brine was higher than that of tuna packed in refined olive oil. The EVOO polyphenols had higher antioxidant activity in the brine samples than in the refined olive oil. The higher antioxidant activity of EVOO polyphenols in tuna packed in brine may be explained by their greater affinity toward the more polar interface between water and the fish oil system.

Animals↗
PubMed1992

Physiological and behavioural thermoregulation in bigeye tuna (Thunnus obesus).

Tuna are unique among teleost fishes in being thermoconserving. Vascular counter-current heat exchangers maintain body temperatures above ambient water temperature, thereby improving locomotor muscle efficiency, especially at burst speeds and when pursuing prey below the thermocline. Because tuna also occasionally swim rapidly in warm surface waters, it has been hypothesized that tuna thermoregulate to accommodate changing activity levels or ambient temperatures. But previous field experiments have been unable to demonstrate definitively short-latency, mammalian-type physiological thermoregulation. Here we show using telemetered data that free-ranging bigeye tuna (Thunnus obesus) can rapidly alter whole-body thermal conductivity by two orders of magnitude. The heat exchangers are disengaged to allow rapid warming as the tuna ascend from cold water into warmer surface waters, and are reactivated to conserve heat when they return into the depths. Combining physiological and behavioural thermoregulation expands the foraging space of bigeye tuna into otherwise prohibitively cold, deep water.

Animals↗
PubMed2005

Migration of bisphenol A (BPA) from can coatings into a fatty-food simulant and tuna fish.

The effect of heat processing, storage time and temperature on the migration of bisphenol A (BPA) from organosol and epoxy can coatings to a fatty-food simulant and tuna was determined. Analyses of BPA were performed by RP-HPLC with fluorescence detection. Four migration experiments, performed between 2000 and 2003, using cans with organosol, epoxy and a combination of both types of coatings were performed under different processing conditions and storage times. Migration levels as high as 646.5 microg kg(-1) BPA from an organosol coating of tuna fish cans were found using a fatty-food simulant following the heat processing of the simulant-filled cans. Levels ranging from 11.3 to 138.4 microg kg(-1) BPA from tuna cans coated with an epoxy resin migrated to the fatty-food simulant during 1 year at 25 degrees C. Levels of BPA migration into a fatty-food simulant from thermally processed and stored tuna cans coated with a combination of organosol and epoxy resins and from vegetable cans coated with an epoxy resin were below the limit of quantitation of 10.0 microg kg(-1). Migration of BPA to tuna ranged from <7.1 to 105.4 microg kg(-1) during long-term storage at 25 degrees C. BPA levels in tuna cans purchased from three local supermarkets ranged from <7.1 to 102.7 microg kg(-1). The highest migration levels were found following heat processing at temperatures as high as 121 degrees C and at times as long as 90 min. Coatings from different can batches can give different levels of BPA migration. The migration levels of BPA found in this work are below the present European Union migration limit, except the 646.5 microg kg(-1) found after the commercial heating process was applied to the simulant-filled cans coated with the organosol resin.

Animals↗
PubMed2003

Electrophysiological properties of the L-type Ca(2+) current in cardiomyocytes from bluefin tuna and Pacific mackerel.

Tunas are capable of exceptionally high maximum metabolic rates; such capability requires rapid delivery of oxygen and metabolic substrate to the tissues. This requirement is met, in part, by exceptionally high maximum cardiac outputs, opening the possibility that myocardial Ca(2+) delivery is enhanced in myocytes from tuna compared with those from other fish. In this study, we investigated the electrophysiological properties of the cardiac L-type Ca(2+) channel current (I(Ca)) to test the hypothesis that Ca(2+) influx would be large and have faster kinetics in cardiomyocytes from Pacific bluefin tuna (Thunnus orientalis) than in those from its sister taxon, the Pacific mackerel (Scombe japonicus). In accordance with this hypothesis, I(Ca) in atrial myocytes from bluefin tuna had significantly greater peak current amplitudes and faster fast inactivation kinetics (-4.4 +/- 0.2 pA/pF and 25.9 +/- 1.6 ms, respectively) than those from mackerel (-2.7 +/- 0.5 pA/pF and 32.3 +/- 3.8 ms, respectively). Steady-state activation, inactivation, and recovery from inactivation were also faster in atrial myocytes from tuna than from mackerel. In ventricular myocytes, current amplitude and activation and inactivation rates were similar in both species but elevated compared with those of other teleosts. These results indicate enhanced I(Ca) in atrial myocytes from bluefin tuna compared with Pacific mackerel; this enhanced I(Ca) may be associated with elevated cardiac performance, because I(Ca) delivers the majority of Ca(2+) involved in excitation-contraction coupling in most fish hearts. Similarly, I(Ca) is enhanced in the ventricle of both species compared with other teleosts and may play a role in the robust cardiac performance of fishes of the family Scombridae.

Animals↗
PubMed1994

Inhibitory effect of tuna peptide on endothelin production in cultured endothelial cells.

The effect of tuna muscle-derived angiotensin-converting enzyme (ACE) inhibitory peptide (tuna AI) on the production of potent contracting factor, endothelin-1 (ET), in the cultured bovine aorta endothelial cells (BAECs) has been investigated. ET production in the culture medium was measured by radioimmunoassay. BAECs spontaneously produced ET in a time-dependent manner for 4 to 24 h after incubation. Addition of tuna AI to the medium resulted in a time- and concentration-dependent decrease in the production of ET. The tuna AI-induced inhibition of ET production was blocked by B-3824 (bradykinin (BK) B2-receptor antagonist), NG-monomethyl-L-Arg and indomethacin, but not by angiotensin II receptor antagonist. While BK, sodium nitroprusside and platelet-derived growth factor (PDGF) significantly inhibited ET production, angiotensin II and interleukin-1 did not. Potent ACE inhibitory peptides among tuna AI analogues did not always inhibit ET production. The results suggest that tuna AI inhibits ET production at least in part via potentiation of PDGF expression in addition to potentiation of BK pathway.

Amino Acid Sequence↗
PubMed1987

Homeothermic fish and hemoglobin: primary structure of the hemoglobin from bluefin tuna (Thunnus thynnus, Scromboidei).

Some fish are warm-bodied, e.g. the bluefin tuna (Thunnus thynnus), which has a muscle temperature 12-17 degrees C higher than its environment. This endothermy is achieved by aerobic metabolism and conserved by means of a heat-exchanger system. The hemoglobins of bluefin tuna are adapted to these conditions by their endothermic oxygenation, thus contributing to the preservation of the body energy. This is a new and so far unique property of tuna hemoglobin. The primary structure of the alpha and beta chains of bluefin tuna hemoglobins is presented. The sequence was determined after enzymatic and chemical cleavages of the chains and sequencing of the peptides in gas- and liquid-phase sequencers. The alpha chains consists of 143 residues and are N-terminally acetylated. The beta chains have 146 amino acids and show two ambiguities at positions 140 and 142. The alpha chains differ from the human alpha chains in 65 amino-acid residues, the beta chains in 76. The hemoglobins of bluefin tuna, carp and man are compared and their different physiological properties are discussed in relation to the sequence data. From the primary structure of tuna hemoglobins, it is possible to propose a molecular basis for their peculiar endothermic transition from the T to the R structure.

Amino Acid Sequence↗
PubMed2001

Effects of feeding tuna oil on the lipid composition of pig spermatozoa and in vitro characteristics of semen.

The aim of the present study was to characterize the effects of feeding tuna oil on the lipid and fatty acid composition of boar spermatozoa and to relate changes in composition to boar semen characteristics. Ten boars were paired by age and allocated to one of two diets (five boars per diet). The diets, which were offered for 6 weeks, consisted of a basal diet that was either unsupplemented or supplemented with 30 g tuna oil kg(-1) diet. Adding tuna oil to the diet increased the ether extract concentration of the diets fed from 65 to 92 g kg(-1) dry matter and supplied 10.5 g long chain polyunsaturated (n-3) fatty acids per 100 g total fatty acids. There were no changes in semen fatty acid composition after 3 weeks of feeding tuna oil. However, after 5 and 6 weeks, the proportions (g per 100 g total fatty acids) of 22:6(n-3) in sperm phospholipid fatty acids were increased from 34.5 to 42.9 g by feeding tuna oil and 22:5(n-6) decreased from 29.8 to 17.9 g. No changes were observed in other sperm lipids or seminal plasma phospholipids as a result of the diets fed. Feeding tuna oil increased the proportion of spermatozoa with progressive motility and with a normal acrosome score and reduced the proportion of spermatozoa with abnormal morphologies.

Animals↗
PubMed2001

[Fatty acids of the tuna of different fishing areas of the Mexican Pacific, canned in oil and water].

A direct relationship exists between the state of health and the diet, and inside this some components, such as the fatty acids (FA), influence mostly in the prevention of certain illnesses (coronary heart disease, hypertension, rheumatoid arthritis, inflammatory answer, and arterial pressure). One of the main sources of essential FA are the marine products; the tuna is a marine food of wide consumption in Mexico due its readiness and low cost. The objective of this work was to determine the profile of fatty acids (FA) in tuna canned in oil and in water coming from three fishing areas of the Mexican Pacific. There were randomly obtained 7 oil-tuna commercial marks (AA) and 5 water- tuna (AW) coming from the next fishery areas: Baja California Sur (L1), Colima (L2) and Mazatlán (L3). The samples without draining were liquefied and thereafter it was obtained the methyl esters of fatty acids that were analyzed by gas chromatography with a flame ionization detector. In all the areas were identified 20 FA (mg/100 g); three AG omega 3 (EPA, DHA and linolenic) and two omega 6 (linoleic and arachidonic). In the AA of the three areas the most abundant saturated FA were estearric and palmitic acids, the most abundant monounsaturated fatty acid was the cis-vaccenic, followed by the oleic acid. The behavior of those omega 3 in the AA of the three areas were similar: with the less quantity was the linolenic acid (447-755), continued by the EPA (979-1323) and finally high concentrations of DHA (1862-3327). In the AW the DHA was the most abundant fatty acid in all the areas (1086-4456), the most abundant monounsaturated fatty acid was the palmitic (640-3809). It was observed the presence of trans fatty acids in high quantities in AW: linolelaidic (1394-1495) and elaidic (377-1234). The relationship omega 3/omega 6 in the AA was similar in L1 and L2, and lower in L3; in AW was higher in L2 and L3. In conclusion, evident variation exists in the content of FA among areas; it could be considered that the AA of L3 and AW of L2 as the richest in omega-3 and omega-6 FA. In general, the tuna in water is a richer food in FA omega 3 and omega 6 that the tuna in oil, independently of the fishery area.

Animals↗
PubMed1996

[Collective scombroid fish poisoning following tuna consumption in Castellon].

BACKGROUND: To investigate and control of a collective scombroid-fish poisoning (SFP) outbreak, that took place in Castellón, Spain. METHODS: Description of the outbreak and case-control study in order to identify risk factors. Active surveillance of SFP cases, and inspection of implicated markets. Histamine determination in urine of cases and foods. RESULTS: During June 1994, 15 cases of SFP were found out, with 12 cases occurred on June, 28 and 29. Five families were affected (attack rate 68.2%). The median incubation period was 45 minutes. Disease symptoms included facial or general flushing, headache, diarrhea, nausea, abdominal pain, and peppery taste. Implicated food was fresh tuna, bought in a hypermarket of Castellón (odds ratio = 26.4, 95% confidence intervals: 1.05-666.8), adjusted by age and sex using logistic regression analysis. Four samples of urine from cases presented histamine concentration above 35 micrograms/l. Three samples of tuna consumed by cases and one sample of tuna from the hypermarket had histamine concentration above a 200 ppm. Considering the situation of risk, remaining suspected tuna was confiscated from the hypermarket. Rest unknown if the descompositions of tuna occurred in the hypermarket or during capture and distribution. CONCLUSIONS: SFP was caused by fresh tuna ingestion with epidemiologic and analytic confirmation. Determination of histamine in urine of patients could permit to confirm SFP.

Adult↗
PubMed1997

Transurethral needle ablation (TUNA) of the prostate: a clinical and urodynamic evaluation.

OBJECTIVES: This prospective study evaluated the clinical and urodynamic changes in patients with obstruction due to benign prostatic hyperplasia (BPH) treated with transurethral needle ablation (TUNA). METHODS: One hundred twenty patients with obstructive uropathy due to BPH were treated with the TUNA procedure between January 1994 and December 1995. All patients were selected according to the criteria established by the guidelines proposed by the International Consensus Committee (World Health Organization, Paris, 1993). The TUNA procedure was performed in an outpatient setting using topical intraurethral anesthesia (2% lidocaine gel). RESULTS: Patients showed a decrease in irritative symptoms as measured by the international Prostate Symptom Score (IPSS) and postprocedure urodynamic parameters. The mean (+/- SD) pretreatment IPSS was 20.8 +/- 4.5. At 3 months, the IPSS decreased to 9.7 +/- 3.0 (108 patients) (P < 0.001). At 6 months it decreased to 6.8 +/- 3.1 (86 patients) and remained at 6.2 +/- 2.9 (72 patients) and 6.7 +/- 3.8 (42 patients) at 12 and 18 months, respectively (P < 0.001). At 1 year after treatment, the peak flow rate (Qmax) increased from 8.2 +/- 3.4 mL/s to 15.9 +/- 2.1 mL/s and was 14.1 +/- 2.5 mL/s at 18 months of follow-up (P < 0.01). Urodynamic re-evaluation performed in 72 patients 12 months after TUNA demonstrated the absence of obstruction in 30 (41.7%). An additional 30 patients (41.7%) had equivocal results, whereas the remaining 12 (16.6%) still had obstruction, according to the Abrams-Griffith nomogram. Mean detrusor pressure at Qmax decreased from 85.3 +/- 18.5 cm H2O to 63.7 +/- 24.9 cm H2O at 12 months of follow-up. CONCLUSIONS: Our results confirm that the TUNA procedure is safe and effective when performed as an outpatient procedure. In addition, TUNA produced better results in patients presenting with moderate to severe irritative symptoms and minimal obstruction as determined by pressure/flow studies.

Catheter Ablation↗
PubMed2000

Source levels and estimated yellowfin tuna (Thunnus albacares) detection ranges for dolphin jaw pops, breaches, and tail slaps.

Tuna fishers in the eastern Pacific Ocean often exploit an association between a few genus of dolphin (Stenella and Delphinus) and yellowfin tuna (Thunnus albacares) to locate and capture the tuna. Identification of a mechanism which facilitates the tuna/dolphin bond may provide a means of exploiting the bond and capturing tuna without catching dolphin. To investigate if tuna may be attracted to low-frequency sounds produced by dolphins, source levels of bottlenose dolphin (Tursiops truncatus) jaw pops, breaches, and tail slaps were experimentally measured and used to estimate the maximum range at which yellowfin could detect similar sounds produced by pelagic species. The effective acoustic stimulus to the tuna was defined as the maximum one-third-octave level between 200 and 800 Hz, the frequency range where T. albacares is most sensitive. Spherical spreading was assumed to predict transmission loss with range. Breaches and jaw pops produced maximum one-third-octave source levels between 200 and 800 Hz of 153 (+/-4) and 163 (+/-2) dB re: 1 microPa-m, respectively, which resulted in estimated detection ranges of 340-840 and 660-1040 m, respectively. Tail slaps had lower source levels [max. 141 (+/-3) dB re: 1 microPa-m] and a maximum detection range of approximately 90-180 m.

Animals↗
PubMed2001

Positive reform of tuna farm diving in South Australia in response to government intervention.

OBJECTIVES: Much of the tuna harvested in South Australia since 1990 has involved "farming" techniques requiring the use of divers. From 1993 to 1995, 17 divers from this industry were treated for decompression illness (DCI). In response, the State Government introduced corrective strategies. A decrease in the number of divers presenting for treatment was subsequently recorded. Consequently, the hypothesis was tested that the government intervention resulted in a decrease in the incidence of DCI in the industry and an improved clinical outcome of divers with DCI. METHODS: The incidence of treated DCI in tuna farm divers was estimated from the number of divers with DCI treated and the number of dives undertaken extrapolated from a survey of the industry in 1997-8. General health was measured in the tuna farm diving population by a valid and reliable self assessment questionnaire. The outcome of the divers treated for DCI was analysed with a modified clinical severity scoring system. RESULTS: The apparent incidence of treated DCI has decreased in tuna farm divers since the government intervention. The evidence supports a truly decreased incidence rather than underreporting. The general health of the tuna farm divers was skewed towards the asymptomatic end of the range, although health scores indicative of DCI were reported after 1.7% of the dives that did not result in recognised DCI. The clinical outcome of the divers treated since the intervention has improved, possibly because of earlier recognition of the disease and hence less time spent diving while having DCI. CONCLUSIONS: The government intervention in the tuna industry in South Australia has resulted in a reduced incidence of DCI in the industry.

Adult↗
PubMed1993

Transurethral needle ablation (TUNA): safety, feasibility, and tolerance of a new office procedure for treatment of benign prostatic hyperplasia.

Many attempts have been made to develop a method for treating benign prostatic hyperplasia (BPH) that is minimally invasive, efficacious, and low cost. The transurethral needle ablation (TUNA) device has recently been developed to treat BPH by selectively ablating hyperplastic prostatic tissue. A special catheter incorporates needles that deliver low-level radiofrequency power directly to a very localized area of the prostate. The needles have adjustable shields to protect the urethra if desired or necessary. It is positioned via transrectal ultrasound or direct vision. A pilot study was performed in patients to evaluate TUNA feasibility via histopathological measurement of thermal lesion size and TUNA safety by: (1) monitoring urethral and rectal temperatures; (2) assessing the ability to localize lesions, and (3) determining patient tolerance of the procedure without anesthesia. Twenty patients were treated using TUNA prior to scheduled retropubic prostatectomy. The surgical prostatic specimens were recovered from 1 day to 1 month after TUNA, were step-sectioned, and examined histologically. Patients were 68 years old on average with prostate weight varying from 14 to 88 g. The TUNA procedure averaged 27 min, 4 lesion treatments per prostate, and 4-15 W of power applied for 3 min. Proximal lesion temperature was about 40-50 degrees C with central lesion temperatures of about 80-100 degrees C. Urethral temperature averaged 37-42 degrees C and rectal temperature remained unchanged. Macroscopic examination of the specimens demonstrated localized lesions averaging 12 x 7 mm. Microscopic examination showed larger lesions of extensive coagulative necrosis averaging 30 x 15 mm. Specific immunohistochemical staining showed destruction of all tissue components.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗