Responses to graded levels of zinc amino acid complex in Nile tilapia (Oreochromis niloticus)

Zinc (Zn) is an essential micronutrient that plays a crucial role in fish development and physiology. This study aimed to evaluate the effects on growth and health in Nile tilapia (Oreochromis niloticus) supplemented with graded levels of zinc amino acid complex (Zn-AA) and subjected to transport stress. Nile tilapia (21.78 ± 0.17 g; (n = 12 fish per tank; stocking density of 1.045 kg- 3) were fed with 0, 25, 50, 75, or 100 mg Zn-AA kg- 1 (equivalent to 77.49, 102.69, 127.89, 153.09, or 178.29 mg Zn kg- 1) in extruded diets (280 g kg- 1 digestible protein; isoproteic and isocaloric) for 60 days. At the end of the experimental period, after growth performance measurements, the fish were transported by car for 3 h, and blood collection was performed. The linear regression showed that the best growth performance (final weight, final biomass, weight gain, specific growth rate, and feed intake) was found in fish fed with 100 mg Zn-AA kg diet- 1 (p < 0.05). The increased dietary Zn-AA increased linearly plasma triglyceride levels, hemoglobin, mean corpuscular hemoglobin, and leukocyte values and reduced plasma total protein, cholesterol (total and LDL), and aspartate aminotransferase levels (p < 0.05). According to quadratic regression, the highest plasma glucose and alanine aminotransferase values were found in the control group (p < 0.05). In conclusion, under the conditions of this study, 100 mg Zn-AA kg diet- 1 is recommended for Nile tilapia as it can improve their growth, metabolism, physiology, and immunity.

Essential oils from Cymbopogon citratus and Lippia sidoides in the anesthetic induction and transport of ornamental fish Pterophyllum scalare

This study verified the effects of essential oils from Lippia sidoides (EOLS) and Cymbopogon citratus (EOCC) on the anesthesia of freshwater angelfish (Pterophyllum scalare) of two different sizes (juveniles I (0.82 g) and II (2.40 g)) and the transport (8 h) of juveniles II. Fish were exposed to different concentrations of EOLS and EOCC: 0, 10, 25, 50, 75, 100, 150, 200, and 250 mg L^-1. Ventilatory rate (VR) and transport for 8 h with 0, 10, and 15 mg L^-1 of each essential oil were evaluated in juveniles II. The major components found in EOLS and EOCC were carvacrol (44.50%) and α-citral (73.56%), respectively. The best sedation and anesthesia times for both essential oils were obtained with 10 and 25 mg L^-1 and 200 and 250 mg L^-1 for juveniles I and II, respectively. Fish sedated with EOLS had lower VR values than the other treatments. Blood glucose levels were higher in ornamental fish transported with 10 and 15 mg EOLS L^-1 and 15 mg EOCC L^-1. Hepatic glycogen values were higher in the control group. In general, fish transported with 10 mg EOLS L^-1 showed fewer gill histological alterations than other transported fish. When the type of lesion was evaluated, the highest gill alterations occurred in fish transported with EOCC. In conclusion, 10 mg EOLS L^-1 could be used to transport of juveniles II because although this concentration increased blood glucose levels, it decreased the VR and muscle glycogen levels and caused only mild alterations to the gills.

Comparison of penalties resulting from first-order and all-order polarization mode dispersion distortions in optical fiber transmission systems

We compare the eye-opening penalty from a first-order polarization mode dispersion (PMD) model with that from an all-order PMD model in optical fiber transmission systems. Evaluating the performance by taking into account only first-order PMD produces a good approximation of the true eye-opening penalty of uncompensated systems when the penalty is low. However, when the penalties are high, this model overestimates the penalty for outage probabilities in the range of interest for systems designers, which is typically approximately 10(-5) to 10(-6).

Controlled field trials of a vaccine against New World cutaneous leishmaniasis

Two controlled, double blind field trials of a non-living promastigote vaccine against New World Cutaneous Leishmaniasis (NWCL) were conducted in 1981 and 1983 in Brazil. Brazilian Army conscripts were randomly assigned to the vaccine or placebo groups and tested during their training in the Amazon jungle, a high risk area for NWCL. The results obtained showed: no significant differences between the vaccine and the placebo groups with respect to a number of characteristics (age, race, previous contact with the jungle, etc.); no significant differences between the participants who got and who did not get NWCL during the trial, with respect to length of exposure, contact with the jungle, etc. and a reduction of 67.3 and 85.7% in the annual incidence rate of NWCL, in 1981 and 1983 respectively (although the difference between incidence rates of the disease in vaccinated and control groups in the 1983 trial was not statistically significant), among those vaccinated who had converted to a positive leishmanin skin test as compared with the placebo groups.

Some characteristics of the hyperreactivity to bacterial lipopolysaccharide induced in mice by Trypanosoma cruzi infection

Mice infected with T. cruzi, Y strain, acquire a high level of susceptibility to the effects of bacterial gram-negative LPS. The LD50 of adult female SW mice to LPS from S. typhosa, decreases from 450 to 2,5 mcg 10-12 days after T. cruzi infection. This hyperreactivity to LPS induced by T. cruzi presents all the characteristics of that found in infection caused by many other agents. During the acute phase of experimental infection with T. cruzi Y strain, mice generally die with a hypovolemic shock very similar to that induced in uninfected animals injected with an adequate dose of bacterial endotoxin. There is evidence for and against the hypothesis that LPS absorbed from the intestinal tract may be involved in the mechanism of death of mice during the acute phase of T. cruzi infection.

Characterization of human heterophil hemolysins induced by Schistosoma mansoni infection

Heterophil antibodies could be detected in sera from normal or from patient with chronic schistosomiasis. Their hemolytic activities depend on the integrity of the complement classic pathway. The heterophil antibodies from patient sera presented a higher specificity for Schistosoma mansoni antigen preparations than those detected in normal sera. Most of the hemolytic activity observed in normal sera can be destroyed at 56ºC for 4 min. On the other hand, about 80% of the sera from infected patients are partially or totally resistant to this heat-treatment. The hemolytic activities of sera were eluted from a gel filtration column in different fractions of the first peak.

Acquired resistance of mice against S. mansoni and lung granulomatous reaction induced by BCG

Studies carried out in Sw outbred mice showed that there is no correlation between the degree of lung granulomatous reaction and the level of acquired resistance against S. mansoni infection induced by BCG.

Immunogenic and protective activity of an extract of Schistosoma mansoni

The immunogenic and protective activity of an extract of S. mansoni, obtained by incubation of viable adult worms in buffered saline, was evaluated in rabbits and mice. Animal immunization with this extract resulted in the development of both humoral and cellular immune response. All immunized rabbits developed high levels (91 to 100%) of cytotoxic antibodies as determined by in vitro assays of cytotoxic activity of their sera against viable schistosomules. Immunized animals challenged with S. mansoni cercariae showed a lower parasite load than that of normal controls. Protective activity was 88.6% and 54.0% in immunized rabbits and mice, respectively.

Isolation of an enriched plasma membrane-subpellicular microtubule fraction of Leishmania mexicana amazonensis

A cell fractionation procedure previously developed for Trypanosoma cruzi was applied to isolated the plasma membrane of promastigotes of Leishania mexicana amazonensis. The cell, swollen in an hypotonic mediun, were disrupted in the presence of a nonionic detergent and the membrane fraction isolated by differencial centrifugation. Electron microscopy showed that the fraction consisted of pieces of the plasma membrane associated with subpellicular microtubules. It was also shown that this fraction is able to induce cell-mediated immune response in mice.

Immunization of mice with Trypanosoma cruzi polyribosomes

Studies were carried out with a polyribosomal fraction isolated from Trypanosoma cruzi Y epimastigotes, with the intention to determine both its immunogenic activity and the degree of protection it could induce against experimental T. cruzi infection. This fraction was assayed in four groups of mice by using different schedules of vaccination and varying the dose, intervals, and route of administration. Seven days after the last dose, the animals were sacrificed for immunological studies or subjected to challenge with T. cruzi trypomastigotes. The results obtained in all schedules showed that our polyribosomal fraction only induced a weak antibody response, but was capable of evoking an expressive cellular response. It was also shown that this fraction has the capacity of inducing a high degree of protection against T. cruzi infection, as determined by the decrease of parasitemia and the prolonged survival time of immunized animals.

Effect of insulin on immunological phagocytosis by macrophages

It was shown that, in physiological concentrations, insulin enhances, in vitro, the immunological phagocytosis of sensitized sheep erythrocytes by cultured mouse peritoneal macrophages. Insulin seems to stimulate macrophage phagocytosis as a cholinomimetic agonist by increasing the intracellular levels of cyclic GMP.

A field trial of a vaccine against American dermal leishmaniasis

A field trial was carried out in the eastern part of the State of Minas Gerais (Brazil) of a vaccine containing killed promastigotes of five stocks of Leishmania. Tests with Montenegro antigen showed that a high proportion of the vaccinated persons became positive within three months, but circulating antibodies were not detected. A proportion of those vaccinated continued to give positive Montenegro reactions for up to three years. Lymphocyte sensitivity tests carried out, on a small sample, three years after vaccination were positive and gave no evidence of immunological depression. No cases of cutaneous or mucocutaneous leishmaniasis occurred in the trial area during the three years of observations.

[Leukocyte migration inhibition with soluble and particulate antigens (author's transl]

Studies were carried out with the leukocyte migration inhibition tests using soluble and particulate antigens (PPD, somatic antigens of T. cruzi, M. bovis (BCG) and leukocytes from patients sensitized to PPD and patients with chronic Chagas' disease. The results obtained showed that the stimulatory capacity of particulate antigens are greater than that of soluble antigens.

[Humoral and cellular immunity in children vaccinated with oral B.C.G. (author's transl)]

The humoral and cellular immunity of 23 children with ages between 1 and 5 years, nonreactors to 10 mu of PPD, were investigated after oral vaccination with one dose of 100 mg of fresh oral BCG, Rio de Janeiro strain (Moreau strain). The tests performed shortly before and 70 days after vaccination showed that the schedule used was neither sufficient to stimulate the production of antibody anti-PPD, nor to change the levels of serum immunoglobulins and T, T-active and B blood lymphocytes. However, about 60% of the children became responsive to 10 mu of PPD after treatment and all gave positive reactions to PPD on "in vitro" assays of leukocyte migration inhibition. New schedules for oral vaccination with fresh BCG are in progress in our laboratory.

Effect of the injection of ribosomes and RNA from Crithidia fasciculata on the experimental infection of mice by Trypanosoma cruzi

Immunization of mice with Crithidia fasciculata (live suspension, ribosomal fraction and purified RNA) induced a certain degree of protection (decrease of parasitaemia) against infection with Trypanosoma cruzi.

Rosette formation by human T and B lymphocytes in the presence of adrenergic and cholinergic drugs

It was shown that adrenergic drugs, which increase the intracellular levels of cAMP, inhibit the rosette formation by T-lymphocytes, but stimulate the rosettes produced by B-lymphocytes. Cholinergic drugs, which increase the levels of cGMP, on the contrary, stimulate the formation of rosettes by T-lymphocytes but inhibit those produced by B-lymphocytes.

Immunologic phagocytosis by macrophages: effect by stimulation of alpha adrenergic receptors

Alpha adrenergic stimulating drugs, metaraminol, norepinephrine, phenylephrine, was found to increase, in vitro, immunological phagocytosis by mice peritoneal macrophages. This effect could be inhibited by dibenamine, a blocking agent. The stimulation by alpha adrenergic agents was similar to that caused by drugs that reduce the intracellular levels of cyclic adenosine monophosphate or by drugs that increase the levels of cyclic guanosine monophosphate.

Attempts to convert lepromatous into tuberculoid-type leprosy with blood lymphocyte extracts from sensitized donors

Two groups of lepromatous patients (L type of leprosy) were injected intramuscularly and respectively with the Lawrence's transfer factor (LTF) or a ribonucleic acid (RNA) extracted from viable blood lymphocytes of healthy donors hypersensitive to lepromin (48–72 hr and 20–30 days), tuberculin (PPD), toxoplasmin and histoplasmin. Each patient received a single dose of LTF or RNA obtained from 10⁹ lymphocytes and was carefully observed for a period of 4 months. Histopathology of skin lesions and of lymph nodes were repeatedly performed. The results of intradermal tests with antigens were read at different times up to 120 days after the injection of LTF and RNA. Delayed cutaneous reaction to some antigens was induced in three patients injected with LTF and in two others injected with RNA. The lepromin reaction read at the end of 48–72 hr and after 20–30 days remained negative in all patients during 120 days of observation. Clinical and histopathologic signs of transformation into tuberculoid leprosy could not be observed in the eight patients tested.