Effects of herbal essential oils used to extend the shelf life of freshwater-reared Asian sea bass fish (Lates calcarifer).

Sensory and microbiological characteristics of Asian sea bass (Lates calcarifer) fish raised in a freshwater pond were evaluated during cold storage for 33 days. Whole fish (averaging 400 g each) were stored in a cold storage room at 0 to 2 degrees C. Essential oils of herbs--thyme (Thymus vulgaris) and oregano (Origanum vulgare)--added at 0.05% (vol/vol) were used as preservatives. On the basis of the sensory test results as well as the bacteriological tests, the addition of oregano and thyme essential oils can considerably slow the process of spoilage. The fish treated with these oils were still fit for human consumption after 33 days of storage. The results obtained through sensory tests are corroborated to a great extent by the chemical (hypoxanthine) tests and to a lesser extent by the physical (Cosmos units) tests. The initial total bacteriological counts were 1.7 x 10(3) CFU/cm2 on the fish surface and <10(2) CFU/g in the fish flesh, and in the control treatment (without preservatives), these counts rose continuously, reaching around 10(7) CFU/cm2 on the fish surface and 10(3) CFU/g in the flesh after 33 days of storage at 0 to 2 degrees C. The use of herbal essential oils as preservatives, on the other hand, resulted in a maximal count of 10(5) CFU/cm2 on the fish surface, while the bacterial count in the flesh remained <10(2) CFU/g by the end of the 33-day storage period at 0 to 2 degrees C.

Effects of storage temperature and preservative treatment on shelf life of the pond-raised freshwater fish, silver perch (Bidyanus bidyanus).

Sensory and microbiological characteristics of pond-raised freshwater silver perch (Bidyanus bidyanus) fish, during cold storage over a period of 25 days were evaluated. Whole fish (averaging 400 g each) were stored in cold storage rooms at either 0 to 2 degrees C, 5 degrees C, or 5 degrees C + potassium sorbate as a preservative. The organoleptic and hypoxanthine test results show that the treatment of potassium sorbate can slow the process of spoilage by about 5 days. Yet, the most important factor affecting the shelf life of these fish is the storage temperature. Keeping the fish at 0 to 2 degrees C can prolong the storage prior to spoilage by 10 days compared with those kept at 5 degrees C. These results obtained through organoleptic tests are corroborated by both the chemical (hypoxanthine and total volatile basic nitrogen) and to some extent by the physical (cosmos) tests. The initial total bacteriological counts were 5 x 10(2) CFU/cm2 for fish surface and <10(2) CFU/g for fish flesh, and these counts rose continuously, reaching about 106 CFU/g (0 to 2 degrees C) and 10(7) CFU/g (5 degrees C) in flesh and 10(7) to 10(8) CFU/cm2 on the surface by the end of the storage period. The addition of potassium sorbate led to a smaller increase in bacterial numbers, especially during the first 15 days. Bacterial composition fluctuated during storage. The initial load on the fish surface was predominantly mesophilic and gram positive and consisted mostly (80%) of Micrococci, Bacillus, and Corynebacterium. During the next 10 days, these bacteria were practically replaced by gram-negative flora comprised mostly of Pseudomonas fluorescens that rapidly increased with storage time and accounted for 95% after 15 days.

Proteolysis by juvenile sea bass (Dicentrarchus labrax) gastrointestinal enzymes as a method for the evaluation of feed proteins.

Protein digestibility by gastrointestinal homogenates of Dicentrarchus labrax, was investigated in 5 feeds in relation to their amino acids composition and their ability to sustain growth of D. labrax post larval juveniles. Gastric proteolysis was found to contribute <25% of the total proteolytic capacity. Correlation was found between intestinal proteolytic capacity and the feed protein content of three pairs of amino acids. The sum of basic amino acids, arginine + lysine in the feed protein exhibited a positive correlation with susceptibility to proteolysis. The sum of the acid amino acids glycine and proline showed a negative correlation.Comparison of the intestinal proteolytic enzymatic activities in 3 growth stages of this species revealed similar profiles. Post larval and large juveniles had similar proteolytic capacities when compared on the basis of equal activity on an artificial substrate of Trypsin. Specific growth rates of post larval fish fed on these 5 feeds correlated positively with their protein digestibility as measured with large juvenile's intestinal homogenates. The results suggest that in this species, the efficiency of feeds in sustaining growth at the post larval stage can be estimated by measuring the feed protein digestibility by the proteolytic system of larger sized juveniles.

Specific L-arginine taste receptor sites in the catfish, Ictalurus punctatus: biochemical and neurophysiological characterization.

We report here the characterization of the arginine binding site(s) and corroborative neurophysiological studies. Binding of L-[3H]arginine to Fraction P2 from taste epithelium was measured by a modification of the method of Krueger and Cagan. Parameters for measuring maximal binding activity were established for both duration of incubation and pH of medium. At pH 7.8, the apparent single rate constant for association (kobs) at 4 degrees C was 4.72 x 10(+5).M-1.min-1. Dissociation was more complex, yielding two rate constants of 1.77.min-1 and 8.34 x 10(-3).min-1. These data suggest the presence of two affinity states for L-arginine. The KD values as calculated from the ratio k-1/k+1 were 1.3 x 10(-6) M and 1.8 x 10(-8) M. Homologous inhibition studies of L-arginine binding were not fit by a simple mass action relationship (Hill Coefficient 0.79), but were best fit by a two-site model with IC50 values of 1.6 x 10(-6) M for the high affinity state and 9 x 10(-4) M for the low affinity state. Multiunit neural recordings examined the stimulatory effectiveness of a number of guanidinium-containing compounds. Compared with L-arginine, only L-arginine methyl ester and L-alpha-amino-beta-guanidino propionic acid (L-AGPA) were effective stimuli. Cross-adaptation experiments demonstrated that at 10(-4) M L-arginine methyl ester, L-AGPA and, to a lesser extent, D-arginine were effective cross-adapting stimuli to 10(-6) M L-arginine. In competition binding studies L-arginine methyl ester, L-AGPA and D-arginine also inhibited binding of L-[3H]arginine (10(-6) M), but each recognized only one affinity state. Inhibition by the poorly cross-adapting stimuli L-glutamate, glycine and L-alanine occurred only above 10(-3) M, indicating that the binding sites for L-arginine are selective. These studies suggest that there are at least two affinity states of L-arginine binding, that the binding sites are specific, and that effective agonists of L-arginine receptors must contain a guanidinium group and an unblocked L-alpha-amino group.

Role of renal prostaglandins in bile-induced diuresis in the dog.

To clarify the possible role of renal prostaglandins (PGs) in the phenomenon of bile-induced diuresis in the dog, we studied the effect of in situ unilateral infusion of bile on kidney function and PGs excretion, before and after PG-synthetase inhibitor administration in anesthetized dogs. The contralateral intact kidney served as control. In the first group of 6 dogs, infusion of bile diluted 1:20 resulted in a significant increase in urinary flow (117%; p less than 0.05), sodium (61%; p less than 0.01), potassium (26%; p less than 0.05), PGE2 (240%; p less than 0.05) and PGF2 alpha (137%; p less than 0.05) excretion rates. Further significant increases in urinary flow, sodium and PGE2 excretion rates were noted with infusion of bile diluted 1:10. All parameters returned to basal levels upon cessation of bile infusion. Significant linear correlation coefficients (p less than 0.005) were found between PGE2 excretion rates and urinary flow (r = 0.72), sodium (r = 0.91) and potassium (r = 0.88) excretion rates. In a second group of 6 dogs, intravenous administration of PG-synthetase inhibitor abolished the increase in renal PGs excretion and the increments in the rates of urinary flow and solute excretion in response to bile infusion. These findings support the notion that the acute diuretic and natriuretic effect of bile, and presumably that of cholemia is mediated, in part, through stimulation of renal PGs synthesis.

Physiology of chemoreceptor cells in the legs of the freshwater prawn, Macrobrachium rosenbergii.

1. Chemoreceptor cells in the first pereiopods (legs) of the freshwater prawn, Macrobrachium rosenbergii, were investigated using single-unit, extracellular electrophysiological recording techniques on an isolated, perfused leg preparation. 2. The cells were responsive to aqueous extracts of food (shrimp, mullet, trout chow), a salt mixture (artificial sea-water), amino acids (L-arginine HCl, taurine), a quaternary ammonium compound (betaine HCl) and ammonium chloride. 3. The response specificity of individual cells ranged from narrow to broad, but on average was broad, being more similar to chemoreceptor cells of freshwater crayfish than of marine spiny or clawed lobsters. 4. Responses were generally excitatory. However, some responses were inhibitory, the first such demonstration in aquatic crustaceans. 5. These electrophysiological results highly correlate with results of feeding behavioral assays carried out on M. rosenbergii.

Responses of freshwater prawn,Macrobrachium rosenbergii, to chemical attractants.

Chemoreception in the adults of the freshwater prawnMacrobrachium rosenbergii was investigated under controlled laboratory conditions, using behavioral assays. Tests were carried out on groups, as well as on individuals, all at their intermolt stages of the molt cycle, and prestarved for three to four days. Of 28 different substances tested, the amino acids taurine, glycine, arginine, and betaine, as well as trimethylamine, elicited a positive behavioral response in at least 50% of the test animals when applied at a threshold concentration of 10(-5)-10(-8) M. A positive response comprises enhanced antennular flicking and food search motion. Of the various nucleotides tested for chemoattraction, only adenosine monophosphate elicited a response similar to that of the above amino acids, although at a concentration of 10(-4) M, whereas adenosine diphosphate required a dosage of 10(-1) M.

Correlation between estradiol and progesterone in cycles with luteal phase deficiency.

Many studies have been published on luteal phase deficiency, and the emphasis in most of them is on progesterone deficiency. In this study 144 patients (455 cycles) with infertility were studied. The patients were divided into four groups. Group 1 consisted of patients with high estradiol and high progesterone levels in the midluteal phase. Group 2 consisted of patients with high estradiol and low progesterone levels. Group 3 consisted of patients with low estradiol and low progesterone levels. Group 4 consisted of patients with low estradiol and high progesterone levels. As expected, patients in groups 2 and 3 showed a low conception rate with outphased endometrial biopsy. However, group 4, in spite of the normal progesterone levels, had a low conception rate with an outphased endometrium. We conclude that estradiol deficiency during the luteal phase is a major factor in infertility, and replacement therapy with progesterone alone in these patients may not improve fertility.

Hypophyseal gonadotropin insufficiency in a young woman with idiopathic hemochromatosis.

A 24-year-old women suffering from primary sterility was diagnosed in 1971 as having idiopathic hemochromatosis (IH). The diagnosis was made on the basis of high serum iron and high transferrin saturation, ferrokinetic studies, including iron absorption, liver biopsy showing heavy deposits of iron in the parenchymatous cells, and a family history. Except for slight elevations in the serum transaminases, there were no clinical or laboratory findings of liver pancreatic, myocardial, or dermal involvement by hemochromatosis. Endocrine evaluation revealed gonadotropin insufficiency as the cause of sterility. The patient was treated with periodic phlebotomies for seven years, and the mount of iron withdrawn during that time was calculated to be approximately 27 g. A repeat liver biopsy showed complete disappearance of the iron excess of the fibrotic changes that had been present in 1971. Repeated relevant clinical and laboratory studies did not reveal any pathological findings consistent with hemochromatosis. A complete endocrine evaluation, including stimulatory tests (luteinizing hormone releasing hormone, thyrotropin-releasing hormone, insulin, and metyrapone), disclosed only findings consistent with hypophyseal gonadotropin insufficiency, and these were attributed to iron deposition. It can be assumed that the prolonged treatment with phlebotomies prevented the development of liver, pancreatic, myocardial, or other clinical endocrine disease, but had no effect on the already damaged pituitary. The patient's clinical course followed the pattern recently described in other young patients with IH.

Iron loading and endocrine functions in nontransfused patients with beta-thalassemia intermedia or sickle-cell thalassemia.

Body iron stores and endocrine functions were determined in eight patients with chronic hemolytic anemia who had received only small amounts of blood and no iron preparations. Four patients had beta-thalassemia intermedia (BTI) and four had sickle-cell thalassemia (SCT). Hemoglobin levels and degrees of hemolysis were similar in both groups of patients. The patients with BTI showed clear evidence of iron overload, whereas there was no evidence of iron accumulation in the patients with SCT. The three patients with BTI who had endocrinologic evaluations showed endocrine dysfunctions. Two patients with SCT had no endocrine abnormalities and the other two probably had some degree of primary hypogonadism. Iron overload in patients with thalassemia probably results from excessive intestinal iron absorption and can damage various parenchymal and endocrine organs, even in the absence of an external source of iron.

[Diagnostic value of serum myoglobin]. / Valore diagnostico della mioglobina serica.

Radioimmunological determination of serum myoglobin in 115 patients is reported. Frankly pathological values were noted in 45/55 subjects with a diagnosis of acute myocardial infarct, whereas 7 displayed only a slight rise, and the remaining 3 proved to be false negatives. Pathological values were observed only 2 hr after the commencement of pain, with maxima after 6-20 hr (mean 10 hr). Values returned tonormal 37 hr after the onset of pain. In patients with angina pectoris, myocardial ischaemia, and pulmonary oedema not due to acute infarct, there was only a slight increase in serum levels, while pathological values were never noted in patients with precordial pain of non-cardiac origin.

Lymphocyte cyclic nucleotide and prostaglandin content in psoriasis: a preliminary report.

Lymphocytes from psoriatic patients were found to contain reduced levels of adenosine 3':5'-cyclic phosphate, guanosine 5'-cyclic phosphoric acid, and prostaglandin E, as compared with lymphocytes from normal subjects. The difference in prostaglandin F levels between psoriatic and control subjects was not statistically significant. These results could point to an immunologic defect in the immune system in psoriasis.

Normalized thyroxine as a screening test for hypothyroidism in full-term and preterm newborn babies.

Thyroid function was assessed in full-term and preterm newborn babies by serum thyroxine (T4), normalized thyroxine (T4N) and thyroid-stimulating hormone (TSH) assays. At age 24 h, there was a significant difference in T4 and TSH values between the full-term and preterm groups; no such difference was found in the T4N values. By 21 days of age, the TSH values were still significantly higher in full-term babies compared with preterm ones, but the T4 values were similar. The T4, T4N and TSH values at 24 h in preterm newborns with respiratory distress syndrome were similar to those in normal preterm babies, and the changes in these values with age had no consistent pattern. In preterm babies with low 24-h T4 and T4N values, these two parameters increased with age, reaching normal adult values by 21 days. We concluded that T4N could serve as a useful thyroid function test in the newborn.