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At least 73 records · Page 4Linked to original sources
PubMed1994

Transurethral needle ablation of the prostate (TUNA): pathological, radiological and clinical study of a new office procedure for treatment of benign prostatic hyperplasia using low-level radiofrequency energy.

Many attempts have been made to develop a method for treating BPH that is minimally invasive, efficacious and low-cost. TUNA is a new, fast anesthesia-free, outpatient device for selectively ablating prostatic tissue by delivering low-level radiofrequency power through a special 22 French urethral catheter positioned in the prostate via TURS and/or direct fiberoptic vision, and outfitted with adjustable needles placed in a selected prostatic area. A pilot study was performed in 70 patients to evaluate TUNA safety and feasibility via histopathological measurement and clinical outcome. Twenty-five patients were treated with TUNA prior to scheduled retropubic prostatectomy. The surgical prostatic specimens recovered from 1 day to 1 month after TUNA were step-sectioned and examined histologically. The TUNA procedure averaged 30 minutes; 4-15 Watts were applied for 3-5 minutes per lesion. The central lesion temperatures were above 100 degrees C. The urethral temperature averaged 41 degrees C and rectal temperature remained unchanged. Macroscopic and MRI examination of the specimens demonstrated localized lesions averaging 12 x 7 mm and 17 x 10 mm for 3 and 5 minutes of treatment, respectively. Microscopic examination of the specimens showed sharply delineated lesions of extensive coagulative necrosis measuring up to 35 x 15 mm. The clinical efficacy of the procedure was evaluated in 25 symptomatic BPH patients treated by TUNA. Tolerance using topical anesthetic and intravenous valium was excellent.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Transurethral needle ablation (TUNA): histopathological, radiological and clinical studies 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. Fifty patients have been treated, twenty-five 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 stepsectioned, and examined histologically. Patients were 69-years-old on average with prostate weight varying from 14 to 88 g. The TUNA procedure averaged 30 minutes, 4 lesion treatments per prostate, and 4-15 W of power applied for 3 to 5 minutes. Proximal lesion temperature was about 40-70 degrees C with central lesion temperatures of about 110 degrees C with central lesion temperatures of about 110 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 for 3 min and 10 x 17 for 5 min treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1998

Immunocytochemical identification of two distinct gonadotropic cells (GTH I and GTH II) in the pituitary of bluefin tuna, Thunnus thynnus.

Immunocytochemical identification of GTH I and GTH II cells in the pituitary of the bluefin tuna (Thunnus thynnus) was performed using antisera specific for the common alpha-subunit and the two distinct beta-subunits of tuna (Thunnus obesus) GTH I and GTH II. Cells of the dorsal part of the proximal pars distalis (PPD), in close association with somatotrophs, displayed immunoreactivity of GTHIbeta. GTH IIbeta immunoreactivity was present in cells of the central part of the PPD and the external border of the pars intermedia. Anti-GTHalpha immunostained both GTH Ibeta- and GTH IIbeta-immunoreactive cells and also thyrotrophs. Both GTH Ibeta- and GTH IIbeta-immunoreactive cells were observed in immature bluefin tuna, although there were greater numbers of GTH IIbeta immunoreactive cells. These results suggest that GTH I and GTH II are synthesized in separate cells in the pituitary of the bluefin tuna. The localization and appearance of the two distinct gonadotropic cells of the tuna are compared with the salmonid arrangement.

Animals↗
PubMed1989

In vivo formation of metabolites of prostaglandins I2 and I3 in the marmoset monkey (Callithrix jacchus) following dietary supplementation with tuna fish oil.

Recent studies have shown that ingestion of eicosapentaenoic acid (EPA) in man results in the formation of 'trienoic' prostanoids which amy partly explain the potent antithrombotic/antiatherogenic properties of long-chain polyunsaturated n-3 fatty acids (PUFAs). However, endogenous formation of cyclooxygenase metabolites of EPA has not been demonstrated in an animal model, and in vitro studies indicate a clear species difference in the conversion of EPA to PGI3. Thus, in the present study, the in vivo formation of PGI3 following long-term dietary tuna fish oil supplementation was investigated in a small non-human primate - the marmoset monkey (Callithrix jacchus). The excretion of major urinary metabolites 2,3-dinor-6-keto-PGF1 alpha (PGI2-M) and delta 17-2,3-dinor-6-keto-PGF1 alpha (PGI3-M) was estimated as an index of total body synthesis of PGI2 and PGI3, respectively. Following extraction, dinor prostanoid metabolites were separated by capillary gas chromatography and identified by negative ion chemical ionization mass spectrometry. Supplementation of the standard (reference) diet with either sheep fat or sunflower seed oil did not alter the body production of PGI2-M. However, following the tuna fish oil-enriched diet, there occurred not only an increase in urinary PGI2-M (reference 70.7 +/- 9.0; tuna fish oil 115.5 +/- 12.1 ng/g creatinine, P less than 0.05), but also a considerable formation of PGI3-M (62.9 +/- 5.3 ng/g creatinine), which was not seen in any other dietary group; in addition, the urinary level of immmunoreactive 2,3-dinor-thromboxane B2/3 was reduced after ingestion of tuna fish oil. These urinary changes were accompanied by a rise in plasma phospholipid-bound EPA and docosahexaenoic acid (DHA). In addition, tuna fish oil supplementation resulted in a significant reduction in plasma cholesterol (53%) and triacylglycerols (44%). The present study provides for the first time experimental evidence for the in vivo formation of PGI3 in an animal model and also confirms the earlier observations in man following dietary fish oil supplementation.

Animals↗
PubMed1988

Molecular cloning and nucleotide sequence of tuna growth hormone cDNA.

cDNA for mRNA of tuna growth hormone (GH) was cloned by screening a cDNA library constructed from tuna pituitary gland poly(A)+ RNA. The nucleotide sequence of cDNA (911 bases) revealed an open reading frame of 615 nucleotides, including a sequence (51 bases) for a possible secretory protein leader peptide. Noncoding regions were found in the nucleotide sequences up- (5'-terminal: 65 bases) and down- (3'-terminal: 231 bases) stream of the open reading frame. An amino-acid sequence deduced from the nucleotide sequence of the cDNA was identical with that determined in the purified tuna GH. Tuna GH was composed of 187 amino acids, and had a calculated molecular weight of 21,275. Amino-acid sequencing showed that there was one possible N-glycosylation site at Asn (Asn-Cys-Thr). Tuna GH showed amino-acid sequence homologies with chum salmon (67%), yellow tail (90%) and with human (32%) growth hormones.

Amino Acid Sequence↗
PubMed1983

Structural and functional aspects of the heart ventricle myoglobin of bluefin tuna.

The heart ventricle myoglobin of bluefin tuna has been purified to an apparent homogeneity. The amino acid analysis has revealed only a limited number of substitutions between the myoglobins of yellowfin and bluefin tuna. The alpha-helix content of tuna myoglobin has been found considerably lower than that of mammalian myoglobin. No correlation has been discovered between the conformational stability and alpha-helix content. Denaturation experiments have shown that the whole structure of tuna myoglobin results from the interaction of two structural units which represent the product of independent folding processes. The structure of tuna myoglobin has been found more open and disorganized than that of sperm whale. This result has been related to the low content of electrostatic interactions and explained in terms of evolutive adaptations.

Amino Acid Sequence↗
PubMed1996

Structural basis for oxygen delivery: muscle capillaries and manifolds in tuna red muscle.

We summarize our morphometric data on fiber vascularization and aerobic capacity in red muscle of tuna (Katsuwonus pelamis), compared to intensely aerobic flight muscles of hummingbird (Selasphorus rufus, BW 3-4 g) and bat (Eptesius fuscus, BW 15-16 g, Pipistrellus hesperus, BW 3-5 g). Three characteristic features of high flux paths for oxygen: (a) small fiber size, (b) dense capillary network and (c) high mitochondrial volume density were found in tuna, but they were not as pronounced as in hummingbird and bat flight muscles. A particular arrangement of capillary manifolds, also seen in flight muscle of birds but not in bats, was found in tuna, forming dense envelopes of capillary branches around portions of muscle fibers. However, all indexes of fiber capillarization were relatively low in tuna red muscle for its mitochondrial volume, compared with other intensely aerobic muscles. Capillary length per unit volume of mitochondria, and capillary surface per mitochondrial inner (and outer) membrane surface area, were about one half of those in hummingbird or bat flight muscles. Consistent differences exist in the size of the capillary network for the size of the mitochondrial compartment in highly aerobic red muscle of tuna compared with bird and mammal.

Aerobiosis↗
PubMed2005

The influence of storage conditions of tuna viscera before fermentation on the chemical, physical and microbiological changes in fish sauce during fermentation.

Effect of storage condition of tuna viscera on chemical, physical and microbiological changes of its sauce were monitored. Results based on microbial counts, protein degradation products, total volatile base (TVB), and trimethylamine (TMA) contents, showed that tuna viscera stored at room temperature underwent more deterioration than that kept in ice, especially with increasing storage time. As a result, fish sauce obtained from tuna viscera stored at room temperature for a longer time rendered the greater amino nitrogen, TVB, TMA contents as well as browning intensity. However, storage conditions had no marked effect on overall changes in chemical, physical and microbiological characteristics of sauce generated during fermentation. Additionally, fish sauce produced from tuna viscera kept at room temperature comprised lower histamine content than that prepared from fresh or ice-stored viscera. Therefore, tuna viscera stored at room temperature for up to 8h could be used for the production of fish sauce with no detrimental effect on the quality.

Analysis of Variance↗
PubMed2006

Routine metabolic rate of southern bluefin tuna (Thunnus maccoyii).

Routine metabolic rate (RMR) was measured in fasting southern bluefin tuna, Thunnus maccoyii, the largest tuna species studied so far (body mass=19.6 kg (+/-1.9 SE)). Mean mass-specific RMR was 460 mg kg(-1) h(-1) (+/-34.9) at a mean water temperature of 19 degrees C. When evaluated southern bluefin tuna standard metabolic rate (SMR) is added to published values of other tuna species, there is a strong allometeric relationship with body mass (423 M(0.86), R(2)=0.97). This demonstrates that tuna interspecific SMR scale with respect to body mass similar to that of other active teleosts, but is approximately 4-fold higher. However, RMR (not SMR) is most appropriate in ram-ventilating species that are physiologically unable to achieve complete rest. Respiration was measured in a large (250,000 l) flexible polypropylene respirometer (mesocosm respirometer) that was deployed within a marine-farm sea cage for 29 days. Fasted fish were maintained within the respirometer up to 42 h while dissolved oxygen dropped by 0.056 (+/-0.004) mg l(-1) h(-1). Fish showed no obvious signs of stress. They swam at 1.1 (+/-0.1) fork lengths per second and several fed within the respirometer immediately after measurements.

Animals↗
PubMed2005

Comparative phylogeography of Atlantic bluefin tuna and swordfish: the combined effects of vicariance, secondary contact, introgression, and population expansion on the regional phylogenies of two highly migratory pelagic fishes.

Comparative phylogeography has revealed remarkable patterns of concordance in the maternal phylogenies of many species. The phylogeography and historical demography of the mitochondrial control region I for 607 Atlantic bluefin tuna (Thunnus thynnus) and 275 swordfish (Xiphias gladius) were analyzed to clarify the complex phylogenetic signals in the North Atlantic-Mediterranean region where they are sympatric. Atlantic bluefin tuna mtDNA is polyphyletic, and includes rare sequences sister to Pacific bluefin tuna (Thunnus orientalis) and introgressed albacore (Thunnus alalunga) sequences. There is no geographic partitioning between Atlantic and Mediterranean samples of Atlantic bluefin tuna (Phi(ST)=0.002). In contrast, Atlantic and Mediterranean swordfish are differentiated (Phi(ST)=0.091) due to the combined effects of vicariance, secondary contact, and dissimilar regional demographic histories. Mediterranean swordfish has substantially less variation, and a more recent history (tau=2.42) than that of Atlantic swordfish (tau=7.02). In spite of the discordant phylogenetic and phylogeographic signals, the demographic history of Atlantic swordfish and Atlantic bluefin tuna (tau=7.51) suggests concordance in the timeline of population expansion. Possible scenarios of cladogenesis, expansion, and contraction, influenced by glacial cycles during the Pleistocene, are formulated.

Animals↗
PubMed1978

Thin-layer chromatographic screening methods for histamine in tuna fish.

Twelve solvent systems were tested for their ability to separate histamine and histidine on a variety of thin-layer coatings. The best solvent-adsorbent systems were: chloroform-methanol-ammonia (2:2:1), methanol-ammonia (20:1), acetone-ammonia (95:5), and double development with (a) n-butanol-acetone-water (2:2:1) and (b) chloroform-methanol-ammonia (12:7:1), all on silica-gel layers. Ninhydrin was used as the visualization reagent. These four systems were then evaluated for their potential use as rapid screening procedures in the detection of possibly deleterious levels of histamine in tuna fish. Successful separation of histamine from the other ninhydrin-positive components of methanolic tuna fish extracts was achieved with all four systems. A sample from a lot of tuna implicated in human illness was found to have a histamine level considerably higher than tuna purchased from a local retail outlet or an extract spiked to a histamine level considered to be a threshold value for toxicity symptoms. The methanol-ammonia (20:1) and chloroform-methanol-ammonia (2:2:1) systems, used with silica-gel plates, are the most promising for rapid preliminary screening of tuna fish extracts for histamine.

Animals↗
PubMed2002

Specific accumulation of persistent organochlorines in bluefin tuna collected from Japanese coastal waters.

Concentrations of persistent organochlorines (OCs) such as PCBs, DDTs, chlordanes (CHLs), HCHs and HCB were determined in the liver of bluefin tuna (Thunnus thynnus) collected from Japanese coastal waters in order to elucidate accumulation profiles and to evaluate the suitability of this species as a biomonitor for pollution in the open sea ecosystem. Concentrations of PCBs, DDTs and CHLs in bluefin tuna increased significantly with body length (30-190 cm). HCHs and HCB residues were comparable among all the sampling regions, and the levels of these chemicals did not show correlation with body length. These results suggest significance of dietary uptake of PCBs, DDTs and CHLs compared to the intake via the gill. On the other hand, equilibrium partitioning with ambient water is a major determinant of the levels of HCHs and HCB in tuna. Body-Length Normalized Values (BLNV) of PCBs, DDTs and CHLs concentrations in bluefin tuna were calculated using the linear regression equation obtained from the plot of concentrations and body length. BLNV of these chemicals on a lipid wt basis, which was adjusted for 100 cm body length, were indicative of the present state water pollution by PCBs, DDTs and CHLs. These results suggest that bluefin tuna is a suitable bioindicator for monitoring OCs contamination in the open sea ecosystem.

Animals↗
PubMed2004

Effect of temperature and glassy states on the molecular mobility of solutes in frozen tuna muscle as studied by electron spin resonance spectroscopy with spin probe detection.

The mobility of solutes in frozen food systems (tuna muscle, sarcoplasmic protein fraction of tuna muscle, and carbohydrate-water) has been studied using the temperature dependence of the shape of electron spin resonance (ESR) spectra of the spin probe 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL). The spin probe was incorporated into the tuna meat from an aqueous solution of TEMPOL or by contact with a layer of TEMPOL crystals. The melting/freezing of freeze-concentrated solutes in frozen tuna meat was observed to take place over a range of temperatures from -25 to -10 degrees C. Lower temperatures gave ESR powder spectra due to the decreased mobility of the spin probe, and the temperature dependence of the mobility of the spin probe did not show abrupt changes at the glass transition temperatures of the systems. The mobility of nonglass forming solutes is concluded to be decoupled from the glass forming components. Similar behavior was also observed for TEMPOL in frozen, aqueous carbohydrate systems. The temperature dependence of the mobility of TEMPOL in the frozen systems was analyzed using the Arrhenius equation, and the logarithm of the Arrhenius preexponential factor tau(a) was found to be linearly correlated with the activation energy for all of the tuna and carbohydrate samples, indicating a common molecular mechanism for the observed mobility of TEMPOL in all of the systems. The linear correlation also suggests that the observed mobility of TEMPOL in the frozen aqueous systems is dominated by enthalpy-entropy compensation effects, where the mobility of TEMPOL is thermodynamically strongly coupled to the closest surrounding molecules.

Animals↗
PubMed2005

Electronic tagging and population structure of Atlantic bluefin tuna.

Electronic tags that archive or transmit stored data to satellites have advanced the mapping of habitats used by highly migratory fish in pelagic ecosystems. Here we report on the electronic tagging of 772 Atlantic bluefin tuna in the western Atlantic Ocean in an effort to identify population structure. Reporting electronic tags provided accurate location data that show the extensive migrations of individual fish (n = 330). Geoposition data delineate two populations, one using spawning grounds in the Gulf of Mexico and another from the Mediterranean Sea. Transatlantic movements of western-tagged bluefin tuna reveal site fidelity to known spawning areas in the Mediterranean Sea. Bluefin tuna that occupy western spawning grounds move to central and eastern Atlantic foraging grounds. Our results are consistent with two populations of bluefin tuna with distinct spawning areas that overlap on North Atlantic foraging grounds. Electronic tagging locations, when combined with US pelagic longline observer and logbook catch data, identify hot spots for spawning bluefin tuna in the northern slope waters of the Gulf of Mexico. Restrictions on the time and area where longlining occurs would reduce incidental catch mortalities on western spawning grounds.

Animal Identification Systems↗
PubMed2006

Genetic identity of YOY bluefin tuna from the eastern and western Atlantic spawning areas.

We used 320 young-of-the-year (YOY) specimens of the highly migratory and overfished Atlantic bluefin tuna, Thunnus thynnus, Linnaeus 1758, to evaluate the hypothesis that Atlantic bluefin tuna comprises 2 stocks with spawning grounds in the Gulf of Mexico and in the Mediterranean Sea. Significant genetic differentiation at 8 nuclear microsatellite loci (F(ST) = 0.0059, P = 0.0005) and at the mitochondrial control region (Phi(ST) = 0.0129, P = 0.0139) was detected among YOY Atlantic bluefin tuna captured on spawning grounds in the Gulf of Mexico (n = 40) versus the western (n = 255) and eastern (n = 25) basins of the Mediterranean Sea. The genetic divergence among spawning populations, combined with the extensive trans-Atlantic movements reported for juvenile and adult Atlantic bluefin tuna, indicates a high degree of spawning site fidelity. Recognition of genetically distinct populations necessitates independent management of Atlantic bluefin tuna on spawning grounds and warrants evaluation of the level of mixing of populations on feeding grounds. The genetic pattern might not have been detected unless juvenile specimens or actively spawning adults had been sampled.

Animals↗
PubMed1981

Nutritional availability to rats of selenium in tuna, beef kidney, and wheat.

Weanling male rats were fed a selenium (Se)-deficient 40% Torula yeast diet for 4 weeks and were then continued on depletion for another 4 weeks or were repleted with 0.1, 0.2, or 0.3 ppm Se as sodium selenite or 0.2 ppm Se as tuna, beef kidney, or high-Se wheat. There were no significant differences in young red blood cell Se, unfractionated red blood cell Se, or liver Se levels in groups fed diets containing 0.2 ppm Se. Glutathione peroxidase (GSH-Px) activity in young red blood cells was lower in the three groups fed food Se than in the group fed selenite (0.2 ppm Se). Young red blood cell GSH-Px was significantly lower in rats fed tuna than in rats fed wheat. Unfractionated red blood cell GSH-Px was lower in rats fed tuna than in rats fed selenite, but did not differ significantly among groups fed food Se sources. Liver GSH-Px was significantly lower in rats fed tuna than in rats fed kidney, wheat, or selenite. Availability of Se was only 54-58% as great from tuna as from selenite for induction of GSH-Px in liver and in red blood cell populations. Therefore, low availability of Se from fish may have to be considered when assessing Se status of human beings from dietary intake.

Animals↗
PubMed1996

The primary structure of the major pepsinogen from the gastric mucosa of tuna stomach.

The complete primary structure of the major component of tuna pepsinogens was determined by conventional protein chemistry methods. It was composed of a prosegment of 37 residues and a pepsin moiety of 323 residues, having a relative molecular mass of 39,364. The essential aspartyl residues in the active site and the three disulfide bonds common to other pepsinogens were conserved; however, several unique substitutions and/or deletions characteristic of tuna pepsinogen were found at various positions, especially in the prosegment and subsite regions, as compared with the sequences of other pepsinogens, which may affect the rate of activation of the zymogen, and/or the catalytic function and substrate specificity of the enzyme. Tuna pepsinogen is the least acidic among pepsinogens. The sequence identity between tuna pepsinogen and other pepsinogens ranged from 45 to 52%. A phylogenetic tree based on the primary structures suggested that tuna pepsinogen diverged from the pepsinogen A and prochymosin groups in an early period of pepsinogen evolution.

Amino Acid Sequence↗
PubMed1997

Heart rate and stroke volume contribution to cardiac output in swimming yellowfin tuna: response to exercise and temperature.

Cardiac performance in the yellowfin tuna (Thunnus albacares, 673-2470 g, 33-53 cm fork length, FL) was examined in unanesthetized fish swimming in a large water tunnel. Yellowfin tuna were fitted with either electrocardiogram electrodes or a transcutaneous Doppler blood-flow probe over the ventral aorta and exposed to changes in swimming velocity (range 0.8-2.9 FLs-1) or to an acute change in temperature (18-28 degrees C). Heart rates (fH) at +/-1 degree C (30-130 beats min-1) were lower on average than previous measurements with non-swimming (restrained) tunas and comparable with those for other active teleosts at similar relative swimming velocities. Although highly variable among individuals, fH increased with velocity (U, in FLs-1) in all fish (fH = 17.93U + 49.93, r2 = 0.14, P < 0.0001). Heart rate was rapidly and strongly affected by temperature (Q10 = 2.37). Blood flow measurements revealed a mean increase in relative cardiac output of 13.6 +/- 3.0% with exercise (mean velocities 1.23-2.10 FLs-1) caused by an 18.8 +/- 5.4% increase in fH and a 3.9 +/- 2.3% decrease in stroke volume. These results indicate that, unlike most other fishes, cardiac output in yellowfin tuna is regulated primarily through increases in fH. Acute reductions in ambient temperature at slow swimming velocities resulted in decreases in cardiac output (Q10 = 1.52) and fH (Q10 = 2.16), but increases in stroke volume (Q10 = 0.78). This observation suggests that the lack of an increase in stroke volume during exercise is not due to the tuna heart operating at maximal anatomical limits.

Animals↗