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F R Lima

Publications and source records attributed to F R Lima.

16 recordsLinked to original sources
PubMed2001

Regulation of microglial development: a novel role for thyroid hormone.

The postnatal development of rat microglia is marked by an important increase in the number of microglial cells and the growth of their ramified processes. We studied the role of thyroid hormone in microglial development. The distribution and morphology of microglial cells stained with isolectin B4 or monoclonal antibody ED1 were analyzed in cortical and subcortical forebrain regions of developing rats rendered hypothyroid by prenatal and postnatal treatment with methyl-thiouracil. Microglial processes were markedly less abundant in hypothyroid pups than in age-matched normal animals, from postnatal day 4 up to the end of the third postnatal week of life. A delay in process extension and a decrease in the density of microglial cell bodies, as shown by cell counts in the developing cingulate cortex of normal and hypothyroid animals, were responsible for these differences. Conversely, neonatal rat hyperthyroidism, induced by daily injections of 3,5,3'-triiodothyronine (T3), accelerated the extension of microglial processes and increased the density of cortical microglial cell bodies above physiological levels during the first postnatal week of life. Reverse transcription-PCR and immunological analyses indicated that cultured cortical ameboid microglial cells expressed the alpha1 and beta1 isoforms of nuclear thyroid hormone receptors. Consistent with the trophic and morphogenetic effects of thyroid hormone observed in situ, T3 favored the survival of cultured purified microglial cells and the growth of their processes. These results demonstrate that thyroid hormone promotes the growth and morphological differentiation of microglia during development.

Animals↗
PubMed2001

Plasma ascorbate concentrations are not correlated with milk somatic cell count and metabolic profile in lactating and dry cows.

The purpose of this study was to determine the effects of stage and the number of lactation on plasma ascorbate concentration and to establish the association between plasma ascorbate concentrations and plasma glucose, insulin, nonesterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), aspartate aminotransferase (AST), milk somatic cell count (SCC), milk yield, and body condition score (BCS) in dairy cows. Holstein cows (n = 193) from three different herds were used in this study. Animals were randomly selected, and assigned to five groups according to stage of lactation (group 1, dry cows; group 2, 1 to 28 d; group 3, 29 to 56 d; group 4, 57 to 140 d; group 5, 141 to 280 d), and the number of lactation (primiparous or multiparous). Plasma ascorbate concentration, plasma glucose concentration, serum insulin concentration, plasma NEFA concentration, plasma BHBA concentration, serum AST concentration, milk SCC, milk yield, and BCS were measured. The results of this study demonstrate that plasma ascorbate concentrations do not change in response to stage of lactation, or number of lactations. Among the several variables studied, none was found that, singly or in combinations, could explain variations in ascorbic acid concentrations.

Animals↗
PubMed2000

Patterns of synthesis and secretion of sulfated glycosaminoglycans in primary cortical and cerebellar astrocytes in vitro.

We determined the amounts of [35S]-glycosaminoglycans (GAGs) found on the intracellular, pericellular and extracellular compartments of primary cultures of astrocytes derived from newborn rat cortex and cerebellum in vitro. Our results show that the greatest portion of newly synthesized GAGs were found in different cellular compartments, depending on the source of the astrocytes. In the cells derived from the cerebellum, the proportion of [35S]-GAGs secreted to the culture medium preponderates over the amount found in the two other compartments, whereas cells derived from the cortex accumulated higher proportions of [35S]-GAGs in the intracellular compartment than in the two other compartments. Cortical and cerebellar glial cells synthesised and secreted heparan sulfate (HS) and chondroitin 4-sulfate (C-4S). HS was predominantly accumulated on the pericellular surface, while C-4S was mostly secreted to the culture medium. Beside the difference on the distribution of total [35S]-GAGs among the three cellular compartments, no difference was observed on the relative proportions of HS and C-4S within each compartment. By defining the source of GAGs, the present study may help to complement and extend information on biosynthesis of these compounds by mammalian glial cells.

Animals↗
PubMed1999

Laboratory evaluations of feed-grade and agricultural-grade phosphates.

Nine samples of pure, feed-grade (FP) and agricultural-grade (AP) phosphates were evaluated at seven laboratories (six in Brazil and one in the U.S.) for physical and chemical characteristics. Phosphates were one "standard" pure dicalcium phosphate; four FP, two dicalcium phosphates (FP-1 and FP-2) made in Brazil, one di-monocalcium phosphate (FP-3), and one defluorinated phosphate (FP-4) made in the U.S.; and four AP made in Brazil [single superphosphate (AP-1), triple superphosphate (AP-2) and monoammonium (AP-3), and thermomagnesium (AP-4) phosphates]. Average analytical values for FP and AP, respectively, were 3.3 and 6.3% moisture, 1.0 and 2.5% insoluble residue, 16.2 and 28.4% loss on ignition, 6.8 and 4.7 (pH), 1,028 and 1,023 g/L apparent density, 9.6 and 55.0% P solubility in water, 83.6 and 88.4% P solubility in 2% citric acid, and 85.2 and 97.0% P solubility in neutral ammonium citrate. Based on particle size, six products were classified as "fine," and three were classified as "irregular." Atomic absorption and plasma spectrometry determinations were performed for 31 essential and potentially harmful or radioactive minerals. The Na level was high in FP-4 (6.03%). Mineral concentrations were safe for all FP as compared with NRC standards. Levels in AP were toxic, exceeding the tolerance limits for F, Fe, Mg, and Ba, and were particularly high as compared with FP for S, Ti, and radioactive Th. The AP-1 was high in F, Ba, S, and Th; AP-2 and AP-3 were high in F and S; and AP-4 was high in F, Ba, Fe, Mg, Ti, and Th. X-ray diffraction assays detected impurities for all commercial samples and identified as major components CaHPO4*2H2O (standard phosphate), CaCO3 and CaHPO4 (FP-1, FP-2, and FP-3), Ca(H2PO4)2*H2O (FP-3), Na2Ca3Al2(PO4)2(SiO4)2 and Ca3(PO4)2 (FP-4), CaSO4*nH2O and (NH4)Fe3P6O20*(PO4)2 (AP-1), Ca(H2PO4)2*H2O and KFe3P6O20*10H2O (AP-2), (NH4)H2PO4 and CaSO4*nH2O (AP-3), and no definite molecular structure for AP-4, an amorphous product. The biological consequences of feeding animals a mineral source with no definite molecular structure, an amorphous product, is not known. A biological evaluation of all phosphates included in this article is being published as a separate report (Fernandes et al., 1999).

Agriculture↗
PubMed1999

Relative bioavailability of phosphorus in feed and agricultural phosphates for poultry.

Nine hundred fifty male Hubbard chicks were used in a 21-d study (10 birds per battery cage) to determine relative bioavailability of P (RBP) in four feed-grade phosphates (FP) [two Brazilian dicalcium and two U.S.-made phosphates (di-monocalcium and defluorinated)] and four Brazilian agricultural grade phosphates (AP) [single (AP-1), and triple (AP-2) superphosphates, monoammonium (AP-3), and thermomagnesium (AP-4) phosphates]. The reference standard was a purified-grade calcium phosphate dibasic (SP). Phosphates were added to the corn-soybean control diet (22% protein; 0.40% P + 0.08% P from SP), providing 0.08 and 0.16% additional P. Calcium level was 1.0% for all diets. Slope ratio was used to determine RBP, with BW, bone ash (BA), or bone strength (BS) regressed on P added within each P source. A relative biological value (RBV) was estimated using BW, BA, and feed efficiency. Performance was depressed (P < 0.01) by AP as compared with FP; BW was decreased by 11%, and feed intake (FI) was decreased by 14%. Mortality increased (P < 0.05) by 154% (7 vs 2.8%). Phosphate source AP-4, which had the lowest content of P and a high content of F, Fe, Ba, Ti, and Th, was toxic based on a 44% decrease (P < 0.01) in BW, 46% decrease in FI, 19% decrease in BA (32.4 vs 40.0%), 55% decrease in BS (7.1 vs 15.8 kg), and mortality increase (P < 0.05) from 0.7 to 26% compared with the average of AP-1, -2 and -3. The RBP could not be estimated for AP-4; and average availabilities for FP and AP, respectively, were 100.6 and 107.6% (BW), 88.3 and 93.2% (BA), 84.2 and 96.3% (BS), and 100.0 and 99.9% (RBP). The AP varied in RBP, with particularly high values calculated for AP-3. Performance and bone parameters in this study were not strongly affected by high levels of potentially toxic mineral elements in certain AP; this result may be explained by the low levels of phosphate addition and the short duration of the feeding period (21 d). However, considering their relatively high levels of F, Fe, Mg, S, Ba, Ti, and Th, agricultural-grade phosphate may represent considerable risk of toxicity for use in animal diets.

Agriculture↗
PubMed1998

Thyroid hormone action on astroglial cells from distinct brain regions during development.

Astrocytes are target to triiodothyronine (T3) hormone action during rat brain development. In this work, we show that astrocytes from distinct developing brain regions are differently responsive to thyroid hormone. Distinctly from embryonic or newborn cerebral hemisphere and mesencephalic astrocytes, newborn cerebellar and embryonic hippocampal astrocytes do not change their morphology in response of hormone treatment. We also analysed protein synthesis and secretion from these T3-treated astrocytes. The results showed a significant increase in protein synthesis in astrocytes from older brain regions. Maximum effect, however, was observed in cerebral hemisphere astrocytes from newborn rats. The protein secretion effect was also more evident in the cerebral hemisphere as well as in cerebellar astrocytes from newborn rats. In addition, we examined T3 effects on GFAP/vimentin expression by culturing 6-day old cerebellar astrocytes. In this case T3 seems to induce GFAP expression which might be occurring as a first step to astrocyte differentiation.

Animals↗
PubMed1997

Biological evaluations of commercial dicalcium phosphates as sources of available phosphorus for broiler chicks.

One thousand male Hubbard chicks were used in a 21-d study (10 birds per battery cage) to determine relative biological availability of phosphorus in seven samples of commercial dicalcium phosphate, expected to contain variable amounts of monocalcium phosphate. Five samples were from established producers in Brazil and two from the U.S. Pure calcium phosphate dibasic dihydrate was used as the reference standard. Phosphates were added to the corn-soybean basal diet (22.5% CP; 0.4% total phosphorus) to provide 0.1, 0.2, and 0.3% supplemental phosphorus. The calcium level was 1.0% for all diets. Left tibias were removed for bone ash (BA) and bone strength (BS) determination. Body weight, feed intake (FI), BA, BS, and plasma phosphorus increased (P < 0.01) and plasma calcium and alkaline phosphatase decreased (P < 0.01) with increasing dietary phosphorus regardless of source. The availability of phosphorus for each test phosphate was determined by slope ratio, with BW, BA, and BS regressed on phosphorus added within each phosphorus source. A relative biological value (RBV) was calculated based on BW, BA, and gain:feed ratio. Availability based on BW ranged from 97.07 to 110.41%. When BA was the criterion, values were 80.32 to 107.84% and for BS were 79.34 to 110.52%. The RBV ranged from 97.55 to 100.60%. Phosphate sources did not vary greatly in phosphorus availability. Overall phosphorus availability averages were higher for BW (103%) and RBV (99%) and lowest for BA (96%) and BS (94%).

Alkaline Phosphatase↗
PubMed1997

Thyroid hormone induces protein secretion and morphological changes in astroglial cells with an increase in expression of glial fibrillary acidic protein.

Thyroid hormone (T3) induces in vitro differentiation of astrocytes from the developing rat brain. T3 treatment induced the appearance of long processes in cultured cerebral hemisphere and mesencephalon astrocytes from embryonic and newborn rats. T3 treatment also produced a change in the morphology of cultured cerebellar astrocytes from 10-day-old rats, but not in cerebellar astrocytes from newborn rats. An increased expression of glial fibrillary acidic protein (GFAP) was also seen in the T3-treated newborn cerebral hemisphere and mesencephalic astrocytes. The morphological changes were induced earlier when the astrocytes were treated with conditioned medium (CM) obtained from cultures previously exposed to T3. Our results show that astrocytes from the developing rat brain are not homogeneous in their responsiveness to T3. Furthermore, the fact that CM produces a response similar to that obtained with T3 treatment but in less time, suggests that T3 might induce the secretion of factors by cultured astrocytes. These factors might, by an autocrine/paracrine effect, induce the expression of GFAP and differentiation in developing brain astrocytes.

Animals↗
PubMed1995

Chemical and physical evaluations of commercial dicalcium phosphates as sources of phosphorus in animal nutrition.

Seven samples of commercial dicalcium phosphate, expected to contain variable amounts of monocalcium phosphate, from five established producers in Brazil and two in the United States, were evaluated and compared with a purified grade calcium phosphate dibasic dihydrate used as a reference standard. All samples were submitted to a wide range of tests at seven laboratories. Each determination was performed at least at two different laboratories, except for moisture, insoluble residue, loss on ignition, and x-ray diffraction assays, obtained from one single laboratory. All phosphate samples studied were in compliance with the manufacturer's levels of guarantee, except for three samples that were slightly out of specification (Ca, P, and F). Particle size patterns were variable, allowing for a classification of two products as "coarse", three as "fine", and three as "irregular". Phosphorus solubility in 2% citric acid ranged from 85.9 to 97.6%, pH from 3.2 to 6.1, and apparent density from 572 to 967 g/L. Atomic absorption or plasma emission spectrometry concentrations (average parts per million) for Al (3,200), As (10), B (14), Ba (165), Bi (< .1), Cd (6), Cr (57), Co (11), Cu (28), Fe (7,515), Hg (< .2), Mg (11,300), Mn (367), Mo (6), Ni (25), Pb (17), Se (< .5), Sb (1.3), Th (19), U (51), V (134), W (< 5), and Zn (152) were safe for all phosphates as compared to NRC standards. X-ray diffraction detected CaCO3 and impurities for all commercial samples, dolomite for three phosphates. Monocalcium phosphate was found in four samples. Aluminum salts present were identified as the low solubility, low toxicity silicates, and phosphates.

Animal Feed↗
PubMedDate not supplied

Necrolytic migratory erythema associated with glucagonoma syndrome: a case report.

Necrolytic migratory erythema is a rare skin condition that consists of migrating areas of erythema with blisters that heal with hyperpigmentation. It usually occurs in patients with an alpha islet cell tumor of the pancreas-or glucagonoma-and when associated with glucose intolerance, anemia, hyperglucagonemia, and weight loss defines the glucagonoma syndrome. We describe a 52-year-old female patient with necrolytic migratory erythema associated with glucagonoma syndrome who had metastatic disease at presentation and passed away one week after her admission. The autopsy showed a tumor in the body of the pancreas, which was diagnosed as a neuroendocrine tumor and confirmed by immunohistochemistry. The diagnosis of necrolytic migratory erythema is a matter of great importance, since it might be an auxiliary tool for the early detection of glucagonoma.

Erythema↗
PubMedDate not supplied

[Iron deficiency in female athletes].

Iron deficiency and anemia have been reported frequently in athletes. In São Paulo-Brazil among elite athletes overt anemia is uncommon, but our studies showed that they were in a borderline anemic state. Sports anemia is used to describe both pseudodilutional anemia and the true anemia of athletes. We studied 12 female young athletes, all with normal hemoglobin. Four athletes had laboratory features (serum ferritin, red cell volume, and/or transferrin saturation) suggestive of iron deficiency. There are association of high iron body stores with cardiac arrhythmia, carotid atherosclerosis, myocardial infarction, liver and colorectal cancer but minor iron deficiency may impair the physical fitness.

Adolescent↗