Towards a better understanding of Ipomoea asarifolia toxicity: evidence of the involvement of a leaf lectin.

Natural intoxication of livestock by ingestion of Ipomoea asarifolia leaves has been reported to occur widely in Brazil. Previous studies carried out by our research group provided strong evidence that a lectin could be involved with the toxic properties of I. asarifolia. To reinforce this hypothesis, a lectin-enriched fraction (LEF) was isolated from I. asarifolia leaves and its toxic effects were assessed. Leaves of I. asarifolia were excised from plants growing widely in the field, mechanically wounded and maintained in a chamber at 25 ± 3 °C for 72h in the dark, under near 100% relative humidity. The leaf proteins were extracted, ammonium sulfate precipitated, chromatographed on DEAE-cellulose and Phenyl-Sepharose to produce LEF that under SDS-PAGE showed a molecular mass of 44.0 kDa and after N-terminal amino acid analysis a primary sequence composed of AGYTPVLDIGAEVLAAGEPY. The in vivo toxicity of LEF assessed by intraorbital injection in mice showed induced severe uncoordinated movements without death. LEF reduced the muscular contraction in a dose depend way and at 29.8 µg/mL (CE(50)) it produces 50% inhibition of contraction, suggesting that LEF blunts autonomic neurotransmission. Isolated rat kidneys were perfused with LEF and no effects on the perfusion pressure or renal vascular resistance were observed, but urinary flow and glomerular filtration rate increased. Moreover, the percentage of tubular transport of Na(+), K(+) and Cl(-) decreased. Histological examination of the kidneys perfused with LEF exhibited little alterations. These toxic effects observed above were concomitant with the increase of LEF hemagglutination activity, which strongly suggest that one of the toxic principles of I. asarifolia is a lectin present in its leaves.

Antivenom action on renal effects induced by Thalassophryne nattereri venom

Thalassophryne nattereri (niquim) is a venomous fish responsible for numerous accidents involving fishermen in northern and northeastern Brazil. The aim of the present investigation was to evaluate the action of antivenom on renal effects caused by Thalassophryne nattereri venom. Isolated kidneys of Wistar rats were perfused with a previously dialyzed Krebs-Henseleit solution containing 6 g% bovine serum albumin. The antivenom action was studied through perfusion pressure (PP), renal vascular resistance (RVR), urinary flow (UF) and glomerular filtration rate (GFR). The niquim venom (1 miug/mL), the antivenom alone (1 miug/mL) or the venom incubated with antivenom were added to the system 30 minutes after the beginning of each perfusion. Previous works have shown venom induced-alterations of renal function parameters. In the isolated rat Kidney, T. nattereri venom (1 miug/mL) increased the perfusion pressure and renal vascular resistance at 60, 90 and 120 minutes. UF and GFR also increased at 60, 90 and 120 minutes when compared with the control group; however, no effects were observed on the percent of sodium (% TNa more control equal 81.1 more or less 0.86; % TNa more 60 equal 78.04 more or less 1.18; % TNa more 90 equal -5.16 more or less 3.34; %TNa more 120 equal 79.49 more or less 0.87) and potassium (%TKcontrol equal 72.29 more or less 1.12; %TK more 60 equal 75.41 more or less 0.65; % TK more 90 equal 71.23 more or less 2.55; % TK more 120 equal 76.62 more or less 1.04) tubular transporto. The administration of the antivenom (1 miug/mL) incubated with venom (1 miug/mL) reduced the changes in PP, RVR, UF and GFR provoked by Thalassophryne nattereri venom. The group perfused with venom alone showed a moderate deposit of a proteinaceous material in the tubules and urinary space.(...)

The role of indomethacin and tezosentan on renal effects induced by Bothrops moojeni Lys49 myotoxin I.

Renal changes determined by Lys49 myotoxin I (BmTx I), isolated from Bothrops moojeni are well known. The scope of the present study was to investigate the possible mechanisms involved in the production of these effects by using indomethacin (10 microg/mL), a non-selective inhibitor of cyclooxygenase, and tezosentan (10 microg/mL), an endothelin antagonist. By means of the method of mesenteric vascular bed, it has been observed that B. moojeni myotoxin (5 microg/mL) affects neither basal perfusion pressure nor phenylephrine-preconstricted vessels. This fact suggests that the increase in renal perfusion pressure and in renal vascular resistance did not occur by a direct effect on renal vasculature. Isolated kidneys from Wistar rats, weighing 240-280 g, were perfused with Krebs-Henseleit solution. The infusion of BmTx-I increased perfusion pressure, renal vascular resistance, urinary flow and glomerular filtration rate. Sodium, potassium and chloride tubular transport was reduced after addition of BmTx-I. Indomethacin blocked the effects induced by BmTx-I on perfusion pressure and renal vascular resistance, however, it did not revert the effect on urinary flow and sodium, potassium and chloride tubular transport. The alterations of glomerular filtration rate were inhibited only at 90 min of perfusion. The partial blockade exerted by indomethacin treatment showed that prostaglandins could have been important mediators of BmTx-I renal effects, but the participation of other substances cannot be excluded. The blockage of all renal alterations observed after tezosentan treatment support the hypothesis that endothelin is the major substance involved in the renal pathophysiologic alterations promoted by the Lys49 PLA(2) myotoxin I, isolated from B. moojeni. In conclusion, the rather intense renal effects promoted by B. moojeni myotoxin-I were probably caused by the release of renal endothelin, interfering with the renal parameters studied.

Avaliação toxicológica do extrato acetato de etila de Spigelia anthelmia Linn, em ratos e camundongos / Toxicological evaluation of an ethyl acetate extract of Spigelia anthelmia Linn in rats and mice

O extrato acetato de etila de Spigelia anthelmia (EASa) mostrou formalmente ser altamente eficaz contra o desenvolvimento larvar e a eclosão de ovos de Haemonchus contorlus, um importante parasito de ruminantes, in vitro. A OL, e a OL,o de EASa foram administradas subcrônica e cronicamente pela via oral em ratos wistar e o perfil bioquímico foi comparado antes e após cada tratamento e com veículo. Vários órgãos foram coletados e processados para análise histopatológica. Os parâmetros hematológicos foram avaliados antes e depois da administração de EASa durante 30 dias. E os efeitos do EASa administrado pela via oral durante o período embriogênico ou organogênico a camundongas gestantes foram estudados. Os efeitos diretos de EASa, in vivo, foram calculados na pressão sangüínea arterial média e no eletrocardiograma (ECG), e in vitro no coração isolado e no átrio isolado de ratos. A administração de EASa não afetou qualquer parâmetro bioquímico, hematológico ou reprodutivo estudado. EASa induziu um efeito hipotensivo de curto prazo em ratos normotensivos sem qualquer alteração concomitante nos parâmetros do ECG. As maiores doses de EASa induziram uma significante diminuição da amplitude de contração do coração e átrio direito. EASa é desprovido de toxicidade significante e tem leves efeitos no sistema cardiovascular(

Effects of Thalassophryne nattereri fish venom in isolated perfused rat kidney.

Thalassophryne nattereri, popularly known as Niquim, is a venomous fish responsible for many accidents in fishermen in the Northeast of Brazil. The effects of T. nattereri venom on renal physiology has not been tested. Isolated kidneys from Wistar rats of 240-280 g weight were perfused with Krebs-Henseleit solution containing 6g% of previously dialyzed bovine serum albumin. The effects of Niquim venom were studied on the perfusion pressure (PP), renal vascular resistance (RVR), urinary flow (UF), glomerular filtration rate (GFR), percent of sodium tubular transport (%TNa(+)), percent of potassium tubular transport (%TK(+)) and percent of chloride tubular transport (%TCl(-)). The venom of T. nattereri (0.3, 1.0, and 3.0 microg/ml) was always added to the system 30 minutes after the beginning of each experiment (n=6). All experiments were preceded by 30 minutes internal control period and an external control group, where kidneys were perfused with only Krebs-Henseleit solution. All three doses tested promoted increases in PP and RVR. The first two doses also increased GFR and UF. The higher dose promoted decreases in GFR, UF, %TNa(+), %TK(+), %TCl(-). In the treated groups we observed hyalin casts inside all tubules and proteinaceous material in the urinary space. We conclude that the effects resulted from niquim venom agents that promoted a direct effect in kidney cells causing the release of vasoactive factors.

The role of phospholipase A(2) and cyclooxygenase in renal toxicity induced by microcystin-LR.

We have shown previously that exposure to microcystin-LR (MCLR) causes renal toxic effects in isolated perfused rat kidney. That study was extended further to approach the perspective of pharmacological blockade of renal toxic effects by MCLR through the use of experimental therapeutic agents. An isolated kidney perfusion system was utilized and samples of urine and perfusate were collected at 10min intervals to determine the levels of inulin, sodium, potassium and osmolality. Dexamethasone (20microg ml(-1)) and indomethacin (10microg ml(-1)) were administered in the beginning of the perfusion and MCLR was employed in a dose of 1microg ml(-1) after an internal control of 30min to evaluate the perfusion pressure (PP), renal vascular resistance (RVR), glomerular filtration rate (GFR) and urinary flow (UF). Dexamethasone and indomethacin antagonized the toxic effects of MCLR on PP, RVR, GFR and UF. Histologic analysis of dexamethasone and indomethacin treated groups did not show any vascular or interstitial alterations. MCLR potentially impairs the renal function, probably causing vascular and glomerular lesions and, promoting renal alterations through direct or indirect actions. These data seem to indicate that the renal alterations promoted by MCLR involves also phospholipase A(2) and arachidonic acid-derived mediators.

Effects of pentoxifylline and nabumetone on the serum levels of IL-1beta and TNFalpha in rats with adjuvant arthritis.

OBJECTIVE AND DESIGN: This study examined whether serum levels of cytokines, IL-1beta and TNFalpha were elevated in rats with adjuvant arthritis in relation to disease progression, and if so, to verify the treatment effects of nabumetone (20 mg/kg, p. o.), a COX-2 inhibitor and pentoxifylline (20 mg/kg, p.o.), a type-4 phosphodiesterase (PDE4) inhibitor, alone or in combination. MATERIALS AND METHODS: Female Wistar rats were used. Freund's complete adjuvant (FCA) was used to induce arthritis. The increment in contralateral hind paw volume (the secondary lesion) was determined by plethysmometry and the serum cytokines were measured by ELISA. RESULTS: In control rats, the serum IL-1beta and TNFalpha levels were greatly elevated on the very first day i.e. 5 h after FCA, and thereupon a progressive decrease in IL-1beta but not TNFalpha was observed until day 30. The secondary arthritic lesion began to increase on day 14 (125+/-26 microl), and attained its peak (330+/-79 microl) on day 21 post-adjuvant injection. The peak arthritic lesion was significantly (p<0.001) less in rats that received nabumetone and pentoxifylline, alone or in combination (20+/-8, 41+/-15 and 65+/-10 microL, respectively). When serum cytokine levels were analysed on day 20 postadjuvant injection, rats treated with pentoxifylline or in association with nabumetone, but not nabumetone alone showed significantly lowered levels of serum TNFalpha. Unlike TNFalpha, serum IL-1beta did not vary significantly. CONCLUSIONS: The drugs nabumetone and pentoxifylline although appearing to produce differential effects on serum cytokine levels, seem to be equally efficacious in attentuating the progression of FCA-induced arthritis. Serum cytokine levels may not accurately reflect the treatment efficacy.

Effects of microcystin-LR in isolated perfused rat kidney.

Microcystin is a hepatotoxic peptide which inhibits protein phosphatase types 1 and 2A. The objective of the present study was to evaluate the physiopathologic effects of microcystin-LR in isolated perfused rat kidney. Adult Wistar rats (N = 5) of both sexes (240-280 g) were utilized. Microcystin-LR (1 microg/ml) was perfused over a period of 120 min, during which samples of urine and perfusate were collected at 10-min intervals to determine the levels of inulin, sodium, potassium and osmolality. We observed a significant increase in urinary flow with a peak effect at 90 min (control (C) = 0.20 +/- 0.01 and treated (T) = 0.32 +/- 0.01 ml g-1 min-1, P<0.05). At 90 min there was a significant increase in perfusate pressure (C = 129.7 +/- 4.81 and T = 175.0 +/- 1.15 mmHg) and glomerular filtration rate (C = 0.66 +/- 0.07 and T = 1.10 +/- 0. 04 ml g-1 min-1) and there was a significant reduction in fractional sodium tubular transport at 120 min (C = 78.6 +/- 0.98 and T = 73.9 +/- 0.95%). Histopathologic analysis of the perfused kidneys showed protein material in the urinary space, suggestive of renal toxicity. These data demonstrate renal vascular, glomerular and urinary effects of microcystin-LR, indicating that microcystin acts directly on the kidney by probable inhibition of protein phosphatases.

Effects of microcystin-LR in isolated perfused rat kidney

Microcystin is a hepatotoxic peptide which inhibits protein phosphatase types 1 and 2A. The objective of the present study was to evaluate the physiopathologic effects of microcystin-LR in isolated perfused rat kidney. Adult Wistar rats (N = 5) of both sexes (240-280 g) were utilized. Microcystin-LR (1 µg/ml) was perfused over a period of 120 min, during which samples of urine and perfusate were collected at 10-min intervals to determine the levels of inulin, sodium, potassium and osmolality. We observed a significant increase in urinary flow with a peak effect at 90 min (control (C) = 0.20 + or- 0.01 and treated (T) = 0.32 + or - 0.01 ml g-1 min(-1), P<0.05). At 90 min there was a significant increase in perfusate pressure (C = 129.7 + or - 4.81 and T = 175.0 + or - 1.15 mmHg) and glomerular filtration rate (C = 0.66 + or - 0.07 and T = 1.10 + or - 0.04 ml g-1 min(-1) and there was a significant reduction in fractional sodium tubular transport at 120 min (C = 78.6 + or - 0.98 and T = 73.9 + or - 0.95 percent). Histopathologic analysis of the perfused kidneys showed protein material in the urinary space, suggestive of renal toxicity. These data demonstrate renal vascular, glomerular and urinary effects of microcystin-LR, indicating that microcystin acts directly on the kidney by probable inhibition of protein phosphatases

Effects of Crotalus durissus cascavella venom in the isolated rat kidney.

Crotalus durissus cascavella (C.d.c) is a snake usually found in scrubland of Brazilian Northeast and its bite constitutes an important public health problem. Isolated kidneys from wistar rats, weighing 240 to 280 g, were perfused with Krebs Henseleit solution containing 6 g% of previously dialysed bovine serum albumin. The effects of C.d.c venom were studied on the perfusion pressure (PP), urinary flow (UF), glomerular filtration rate (GFR), percent of sodium tubular transport (%TNa+) and percent of proximal tubule sodium transport (%pTNa+). All experiments were preceded by a 30 min internal control period and an external control group. The infusion of C.d.c (10 microg ml(-1)) increased the PP, UF at 60 and 90min of perfusion, and decreased the GFR, %TNa+ and %pTNa+ at 120 min of perfusion. The proximal renal tubule was the major site for this toxic effect. In the group treated with the venom we found hyalin cylinders inside all tubules and proteinaceous material, alternating from moderate to intense presence in urinary space. Dexamethasone (Dexa 20 microg ml(-1)) protected against the increase in PP, UF, and against the decrease in GFR, it produced the reversion of the effect also in %TNa+ and %pTNa+. Indomethacin (Indo 10 microg ml(-1)) antagonized the effect observed in PP and UF, but was not able to reverse the changes in GFR, %TNa+ and %pTNa+. Nifedipine (Nif 10 microg ml(-1)) promoted a reversion of almost all functional changes, except the %pTNa+ was not reversed. We conclude that these alterations may be caused by a direct action of the venom on the kidneys and indirectly by the release of mediators from endothelial cells. Dexa protected against renal lesions caused by the venom, perhaps by inhibiting phospholipase A2 a toxic component of the venom. The reversion partially induced by indo may be due to cyclooxygenase inhibition that will inhibit the formation of prostaglandins. Nif blocked the renal alterations that may involve cell calcium influx that resulted from the venom aggression.

Involvement of the central nervous system in dengue fever: three serologically confirmed cases from Fortaleza Ceará, Brazil.

Three cases of dengue fever involving the central nervous system (CNS) are reported. All occurred in 1994 during a dengue (DEN) epidemic caused by serotypes DEN-1 and DEN-2. The first case examined was a 17-year-old girl who complained of fever, nuchal rigidity and genital bleeding. Three blood samples were positive by anti-dengue IgM ELISA and showed hemagglutination-inhibition (HI) test titers > or = 1,280. The second case concerned a 86-year-old women with fever, muscle and joint pains, altered consciousness, syncope, nuchal rigidity and meningismus. Her blood sample showed an HI titer of 1:320 for flaviviruses, and an IgM ELISA positive for dengue. The third case was a 67-year-old women with fever, abnormal behaviour, seizures, tremor of extremities, thrombocytopenia, increased hematocrit and leukopenia. The patient suffered a typical case of dengue hemorrhagic fever with ensuing shock and a fatal outcome. A single blood sample showed HI antibodies of > or = 1,280 and an IgM ELISA positive for dengue. No virus could be isolated from any patient by inoculation of blood into C6/36 cells and suckling mice. No other agent of disease was encountered in the patient.

Protective effect of ternatin, a flavonoid isolated from Egletes viscosa less., in experimental liver injury.

The effect of ternatin, a tetramethoxyflavone from Egletes viscosa Less., on liver injury induced by carbon tetrachloride (CCl4) was investigated in rats. Twenty-four hours following CCl4 insult (2.5 ml/kg s.c.), changes in the serum enzymes, alanine aminotransferase, aspartate aminotransferase and gamma-glutamyltransferase, as well as liver cell histology were used as indices of hepatic dysfunction. The results show that ternatin (30 mg/kg i.p. daily for 5 consecutive days) causes marked inhibition of CCl4-induced serum enzymes and morbid histologic changes. The observation suggests that ternatin possesses antihepatotoxic activity.

[Cutaneous parasitism by Leishmania (Leishmania) chagasi during South American visceral leishmaniasis]. / Parasitisme cutané par Leishmania (Leishmania) chagasi au cours de la leishmaniose viscérale sud-américaine.

Eighteen patients from the northeastern Brazilian State of Ceara with proven kala-azar were studied for evidence of skin parasitism: two had ulcerative or papular skin lesions and 16 had clinically normal skin. Punch biopsies (3 mm) of intact paraspinal subscapular skin were performed on all patients; in those with papular or ulcerative lesions biopsies also were taken from an active site. One of each of the subscapsular biopsies and half of each biopsy from an active lesion were studied; the other specimens were seeded on NNN Difco Blood Agar Base Medium for parasite culture. The biopsies revealed a discrete to intense mononuclear inflammatory infiltrate, predominantly perivascular in nature. No amastigotes were observed in any tissue sections but 7 of the 18 patients yielded promastigotes on skin culture identified by monoclonal antibodies and by enzyme electrophoresis as Leishmania (Leishmania) chagasi [L. (L.) chagasi]. The isolation of Leishmania (Leishmania) chagasi, the recognized aetiologic agent of visceral leishmaniasis in the New World, from the skin of nearly 40% of 18 AVL patients proves dermatotropism of L. (L.) chagasi occurs and may be frequent in neotropical human visceral leishmaniasis (AVL.). Infected persons with skin parasites could act as a reservoir of infection and allow human to human transmission.

Tumor de Wilms no HIAS. / Wilms' tumor at the Hospital Infantil Albert Sabin

Os autores se propoem a relatar o estudo restrospectivo sobre tumor de Wilms, em pacientes admitidos e tratados no Hospital Infantil Albert Sabin, da FUSEC, no periodo de fevereiro de 79 a fevereiro de 83.Neste periodo foram admitidas 16 criancas portadoras dessa patologia, todas submetidas ao tratamento classico preconizado para tumor de Wilms, constando basicamente de cirurgia radical, quimioterapia e radioterapia pos-operatorias. Neste estudo foram aventados e analisados os seguintes parametros: 1 - Correlacao entre a sobrevida e o estadiamento clinico-cirurgico.2Correlacao entre sobrevida e estadiamento histologico.3 - Achados radiologicos (urograficos). 4 - Correlacao entre as condicoes clinicas no momento da internacao e sobrevida. Os autores concluiram que: 1- A sobrevida global nao foi tao satisfatoria como era de se esperar, em funcao dos estadios clinicos avancados e das mas condicoes clinicas iniciais. 2 - O numero relativamente grande de estadios II (de pessimo prognostico) contribuiu para o aumento da mortalidade. 3 - A histologia favoravel demonstrou melhorar o prognostico mesmo em estadios clinicos avancados (sobrevida longa em estadio IV)

Morphological and histochemical study of the salivary glands of Marmosa agilis agilis.

Foram estudadas a histologia e a histoquimica dos polisacarideos em glandulas salivares parotida, sub-mandibular e sublingual de Marmosa agilis agilis, apos aplicacao de varios metodos. As glandulas parotida e submandibular apresentaram como caracteristica fundamental consideravel quantidade de ductos estriados agrupados de localizacao intralobular, enquanto a glandula sublingual se caracterizou pela ausencia destas estruturas.Atraves de tecnicas histoquimicas foi detectada a presenca de polissacarideos neutros em todas as glandulas salivares e polissacarideos acidos sulfatados e acido sialico apenas na glandula sublingual

Aspecto histologico do epitelio do pterigio. / Histologic aspects of the epithelium of pterygium

O epitelio do pterigio apresenta, como principal alteracao, a metaplasia escamosa. Ela e tambem predominante e parece uma sua caracteristica. Ha comumente pigmentacao melanica assim como pseudo-glandula. A presenca de glandulas, mesmo nao sendo muito frequente, nao pode ser considerada como anomalia. A presenca de displasia, relativamente alta, sugere a observacao do pterigio como campo potencial de neoplasias

Esteatose maligna da gravidez: a proposito de um caso. / Malignant steatosis in pregnancy: apropos of a case

Este e um caso de esteatose maligna da gravidez, patologia rara e com indice de mortalidade materna da ordem de 85% e fetal de 75%.Ocorre geralmente no terceiro trimestre da gestacao com caracteristicas clinicas, bioquimicas e histopatologicas semelhantes aquelas vistas na esteatose induzida por tetraciclina. Embora a etiologia seja desconhecida e a fisiopatologia obscura, a terapeutica baseia-se em medidas de apoio e interrupcao da gravidez antes do termo