Estudo anatômico foliar do clone híbrido 4430 de Tradescantia: alterações decorrentes da poluição aérea urbana

Estudos epidemiológicos mostram uma relação entre a poluição aérea em centros urbanos e a taxa de doenças respiratórias na sua população. Em São Paulo, a concentração dos principais poluentes aéreos é monitorada pela CETESB porém, tais dados não dão idéia do risco ao qual a população está sujeita; plantas bioindicadoras podem dar idéia deste risco. O clone híbrido 4430 de Tradescantia vem sendo utilizado em bioensaios (Trad-MCN, Trad-SH) que avaliam o efeito genotóxico de várias substâncias. Não há registros das potencialidades de bioindicação relativas à estrutura das folhas do clone. Este estudo objetivou estabelecer o padrão estrutural da folha do clone e verificar se existem características anatômicas afetadas pela poluição, que podem ser utilizadas como bioindicadoras. Para tanto, plantas do clone 4430 procedentes da EMBRAPA-Jaguariúna-SP (fora da influência da poluição da cidade de São Paulo -- material controle) foram cultivadas em condições padronizadas e expostas em três pontos distintos da cidade: Instituto de Botânica, Cerqueira César e Congonhas onde permaneceram por três meses. A análise da estrutura da folha mostrou que a mesma apresenta: epiderme uniestratificada com tricomas tectores e glândulares nas duas superfícies, estômatos diacíticos, mesofilo com parênquima lacunoso, frouxamente disposto, colênquima do tipo angular distribuído junto às nervuras, feixes vasculares colaterais e parênquima aquífero na região da nervura central. Qualitativamente não foram observadas variações entre as folhas provenientes dos quatro locais estudados porém, quantitativamente, foram encontradas reduções estatisticamente significativas no tamanho dos estômatos, no diâmetro do metaxilema e na espessura da folha, que podem ser atribuídas ao efeito da poluição. Tais parâmetros anatômicos podem ser utilizados como indicadores do efeito da poluição nessa planta e a mesma pode ser utilizada como bioindicadora do ponto de vista estrutural.

Molecular mimicry between cardiac myosin and Trypanosoma cruzi antigen B13: identification of a B13-driven human T cell clone that recognizes cardiac myosin

Previous reports from our group have demonstrated the association of molecular mimicry between cardiac myosin and the immunodominant Trypanosoma cruzi protein B13 with chronic Chagas' disease cardiomyopathy at both the antibody and heart-infiltrating T cell level. At the peripheral blood level, we observed no difference in primary proliferative responses to T. cruzi B13 protein between chronic Chagas' cardiopathy patients, asymptomatic chagasics and normal individuals. In the present study, we investigated whether T cells sensitized by T. cruzi B13 protein respond to cardiac myosin. T cell clones generated from a B13-stimulated T cell line obtained from peripheral blood of a B13-responsive normal donor were tested for proliferation against B13 protein and human cardiac myosin. The results showed that one clone responded to B13 protein alone and the clone FA46, displaying the highest stimulation index to B13 protein (SI = 25.7), also recognized cardiac myosin. These data show that B13 and cardiac myosin share epitopes at the T cell level and that sensitization of a T cell with B13 protein results in response to cardiac myosin. It can be hypothesized that this also occurs in vivo during T. cruzi infection which results in heart tissue damage in chronic Chagas' disease cardiomyopathy

Autoradiography reveals regional metabolic differences in the endometrium of pregnant and nonpregnant mice

The rodent endometrium undergoes remarkable modifications during pregnancy, resulting from a redifferentiation of its fibroblasts. During this modification (decidualization), the fibroblasts transform into large, polyhedral cells that establish intercellular junctions. Decidualization proceeds from the subepithelial stroma towards the deep stroma situated next to the myometrium and creates regions composed of cells in different stages of differentiation. We studied by autoradiography whether cells of these different regions have different levels of macromolecular synthesis. Radioactive amino acids or radioactive sulfate were administered to mice during estrus or on different days of pregnancy. The animals were killed 30 min after injection of the precursors and the uteri were processed for light microscope autoradiography. Silver grains were counted over cells of different regions of the endometrium and are reported as the number of silver grains per area. Higher levels of incorporation of amino acids were found in pregnant animals as compared to animals in estrus. In pregnant animals, the region of decidual cells or the region of fibroblasts transforming into decidual cells showed the highest levels of synthesis. Radioactive sulfate incorporation, on the other hand, was generally higher in nonpregnant animals. Animals without decidual cell transformation (nonpregnant and 4th day of pregnancy) showed a differential incorporation by subepithelial and deep stroma fibroblasts. This study shows that regional differences in synthetic activity exist in cells that are in different stages of transformation into decidual cells as well as in different regions of the endometrium of nonpregnant mice

Differences between remaining ability and loss of capacity in maximum aerobic impairment

In the evaluation of exercise intolerance of patients with respiratory diseases the American Medical Association (AMA) and the American Thoracic Society (ATS) have proposed similar classifications for rating aerobic impairment using maximum oxygen uptake (VO2max) normalized for total body weight (ml min-1 kg-1). However, subjects with the same VO2max weight-corrected values may have considerably different losses of aerobic performance (VO2max expressed as % predicted). We have proposed a new, specific method for rating loss of aerobic capacity (VO2max, % predicted) and we have compared the two classifications in a prospective study involving 75 silicotic claimants. Logistic regression analysis showed that the disagreement between rating systems (higher dysfunction by the AMA/ATS classification) was associated with age >50 years (P<0.005) and overweight (P = 0.04). Interestingly, clinical (dyspnea score) and spirometric (FEV1) normality were only associated with the VO2max, % predicted, normal values (P<0.01); therefore, in older and obese subjects the AMA/ATS classification tended to overestimate the aerobic dysfunction. We conclude that in the evaluation of aerobic impairment in patients with respiratory diseases, the loss of aerobic capacity (VO2max, % predicted) should be used instead of the traditional method (remaining aerobic ability, VO2max, in ml min-1 kg-1).

Neuroethologic differences in sleep deprivation induced by the single- and multiple-platform methods

It has been proposed that the multiple-platform method (MP) for desynchronized sleep (DS) deprivation eliminates the stress induced by social isolation and by the restriction of locomotion in the single-platform (SP) method. MP, however, induces a higher increase in plasma corticosterone and ACTH levels than SP. Since deprivation is of heuristic value to identify the functional role of this state of sleep, the objective of the present study was to determine the behavioral differences exhibited by rats during sleep deprivation induced by these two methods. All behavioral patterns exhibited by a group of 7 albino male Wistar rats submitted to 4 days of sleep deprivation by the MP method (15 platforms, spaced 150 mm apart) and by 7 other rats submitted to sleep deprivation by the SP method were recorded in order to elaborate an ethogram. The behavioral patterns were quantitated in 10 replications by naive observers using other groups of 7 rats each submitted to the same deprivation schedule. Each quantification session lasted 35 min and the behavioral patterns presented by each rat over a period of 5 min were counted. The results obtained were: a) rats submitted to the MP method changed platforms at a mean rate of 2.62 ± 1.17 platforms h-1 animal-1; b) the number of episodes of noninteractive waking patterns for the MP animals was significantly higher than that for SP animals (1077 vs 768); c) additional episodes of waking patterns (26.9 ± 18.9 episodes/session) were promoted by social interaction in MP animals; d) the cumulative number of sleep episodes observed in the MP test (311) was significantly lower (chi-square test, 1 d.f., P<0.05) than that observed in the SP test (534); e) rats submitted to the MP test did not show the well-known increase in ambulatory activity observed after the end of the SP test; f) comparison of 6 MP and 6 SP rats showed a significantly shorter latency to the onset of DS in MP rats (7.8 ± 4.3 and 29.0 ± 25.0 min, respectively; Student t-test, P<0.05). We conclude that the social interaction occurring in the MP test generates additional stress since it increases the time of forced wakefulness and reduces the time of rest promoted by synchronized sleep.

Gender differences in the activities of aspirin-esterases in rat tissues

The activities of aspirin (acetylsalicylic acid)-esterases were measured in several tissues (liver, kidney, adrenal glands, brain and serum) from adult male and female Wistar rats. In males, both aspirin-esterase I (assayed at pH 5.5) and II (assayed at pH 7.4) activities were higher in liver homogenates when compared to females (aspirin-esterase I: males 48.9 ± 4.8 (N = 8) and females 29.3 ± 4.2 (N = 8) nmol of salicylic acid formed min-1 mg protein-1; aspirin-esterase II: males 41.4 ± 4.1 (N = 8) and females 26.1 ± 4.5 (N = 8) nmol of salicylic acid formed min-1 mg protein-1, P<0.001). In serum, enzyme activity was higher in females than in males (aspirin-esterase I: males 0.85 ± 0.06 (N = 6) and females 1.18 ± 0.11 (N = 6) nmol of salicylic acid formed min-1 mg protein-1; aspirin-esterase II: males 1.03 ± 0.13 (N = 6) and females 1.34 ± 0.11 (N = 6) nmol of salicylic acid formed min-1 mg protein-1, P<0.001). In the other tissues assayed, no statistically significant difference between males and females was found. There were no statistically significant differences when the enzymes were assayed in different phases of the estrous cycle in liver and serum. These results show that the differences in aspirin-esterase activity observed between males and females are not due to the estrous cycle. The gender difference obtained in our study may indicate an involvement of gonadal hormones in the control of the hydrolysis of aspirin. This possibility is currently under investigation.

Sex-dependent differences in the activities of acetylsalicylic acid-esterases in mouse kidneys

Acetylsalicylic acid (ASA), the most used drug worldwide, is hydrolyzed to salicylic acid and acetate by esterases present in tissues of several species including humans. Sex differences in drug metabolism by rodent liver are documented in the literature. In this paper we report a difference in the activities of the esterases (ASA-esterase I and II) in the kidneys of male and female mice. In this species there is no difference between males and females in liver ASA-esterases (ASA-esterase I: males 38.5 ± 7.9 (N = 5) and females 31.6 ± 7.6 (N = 5) nmol of salicylic acid formed min-1 mg protein-1, P>0.05; ASA-esterase II: males 77.3 ± 17.4 (N = 5) and females 61.4 ± 15.1 (N = 5) nmol of salicylic acid formed min-1 mg protein-1, P>0.05). However, in the kidneys males presented a much higher enzyme activity than females (ASA-esterase I: males 25.2 ± 6.3 (N = 5) and females 6.8 ± 0.6 (N = 5) nmol of salicylic acid formed min-1 mg protein-1, P<0.0002; ASA-esterase II: males 79.8 ± 10.1 (N = 5) and females 13.0 ± 1.1 (N = 5) nmol of salicylic acid formed min-1 mg protein-1, P<0.0001). The difference between sexes observed in mouse kidneys could serve as a model to study the molecular basis of this sex difference and also to determine the possible involvement of pituitary and gonadal hormones in this difference in ASA-esterase activities since these hormones control the sex differences in rodent liver enzyme activity.

Pharmacological differences between memory consolidation of habituation to an open field and inhibitory avoidance learning

Rats implanted bilaterally with cannulae in the CA1 region of the dorsal hippocampus or the entorhinal cortex were submitted to either a one-trial inhibitory avoidance task, or to 5 min of habituation to an open field. Immediately after training, they received intrahippocampal or intraentorhinal 0.5-µl infusions of saline, of a vehicle (2% dimethylsulfoxide in saline), of the glutamatergic N-methyl-D-aspartate (NMDA) receptor antagonist 2-amino-5-phosphono pentanoic acid (AP5), of the protein kinase A inhibitor Rp-cAMPs (0.5 µg/side), of the calcium-calmodulin protein kinase II inhibitor KN-62, of the dopaminergic D1 antagonist SCH23390, or of the mitogen-activated protein kinase kinase inhibitor PD098059. Animals were tested in each task 24 h after training. Intrahippocampal KN-62 was amnestic for habituation; none of the other treatments had any effect on the retention of this task. In contrast, all of them strongly affected memory of the avoidance task. Intrahippocampal Rp-cAMPs, KN-62 and AP5, and intraentorhinal Rp-cAMPs, KN-62, PD098059 and SCH23390 caused retrograde amnesia. In view of the known actions of the treatments used, the present findings point to important biochemical differences in memory consolidation processes of the two tasks.

Functional differences between two morphologically distinct cell subpopulations within a human colorectal carcinoma cell line

The LISP-I human colorectal adenocarcinoma cell line was isolated from a hepatic metastasis at the Ludwig Institute, São Paulo, SP, Brazil. The objective of the present study was to isolate morphologically different subpopulations within the LISP-I cell line, and characterize some of their behavioral aspects such as adhesion to and migration towards extracellular matrix components, expression of intercellular adhesion molecules and tumorigenicity in vitro. Once isolated, the subpopulations were submitted to adhesion and migration assays on laminin and fibronectin (crucial proteins to invasion and metastasis), as well as to anchorage-independent growth. Two morphologically different subpopulations were isolated: LISP-A10 and LISP-E11. LISP-A10 presents a differentiated epithelial pattern, and LISP-E11 is fibroblastoid, suggesting a poorly differentiated pattern. LISP-A10 expressed the two intercellular adhesion molecules tested, carcinoembryonic antigen (CEA) and desmoglein, while LISP-E11 expressed only low amounts of CEA. On the other hand, adhesion to laminin and fibronectin as well as migration towards these extracellular matrix proteins were higher in LISP-E11, as expected from its poorly differentiated phenotype. Both subpopulations showed anchorage-independent growth on a semi-solid substrate. These results raise the possibility that the heterogeneity found in the LISP-I cell line, which might have contributed to its ability to metastasize, was due to at least two different subpopulations herein identified.

Pollen mother cells of Tradescantia clone 4430 and Tradescantia pallida var. purpurea are equally sensitive to the clastogenic effects of X-rays

The Tradescantia micronucleus test is a sensitive bioassay for mutagenesis that may be employed both under field and laboratory conditions. This test has been standardized mostly on the basis of the results obtained with clone 4430. However, this clone is not well adapted to tropical weather, frequently showing problems with growth and flowering. In addition, it is attacked by parasites and insects, a fact that limits its use in field studies aiming at the biomonitoring of air pollution. In the city of São Paulo, Tradescantia pallida (Rose) Hunt. var. purpurea Boom is widely distributed as an ornamental plant in gardens and along roadsides and streets, mostly because of its natural resistance and its easy propagation. In this report, we present dose-response curves indicating that the sensitivity of T. pallida and clone 4430 to X-radiation (1, 10, 25 and 50 cGy) is similar. The results confirm our previous suggestion that T. pallida represents a good alternative for in situ mutagenesis testing in tropical regions, especially biomonitoring studies in which the exposure conditions may not be fully controllable.

Gender differences in vascular expression of endothelin and ET A/ET B receptors, but not in calcium handling mechanisms, in deoxycorticosterone acetate-salt hypertension

We determined if the increased vascular responsiveness to endothelin-1 (ET-1) observed in male, but not in female, DOCA-salt rats is associated with differential vascular mRNA expression of ET-1 and/or ET A/ET B receptors or with functional differences in Ca2+ handling mechanisms by vascular myocytes. Uninephrectomized male and female Wistar rats received DOCA and drinking water containing NaCl/KCl. Control rats received vehicle and tap water. Blood pressure and contractile responses of endothelium-denuded aortic rings to agents which induce Ca2+ influx and/or its release from internal stores were measured using standard procedures. Expression of mRNA for ET-1 and ET A/ET B receptors was evaluated by RT-PCR after isolation of total cell RNA from both aorta and mesenteric arteries. Systolic blood pressure was higher in male than in female DOCA rats. Contractions induced by Bay K8644 (which activates Ca2+ influx through voltage-operated L-type channels), and by caffeine, serotonin or ET-1 in Ca2+-free buffer (which reflect Ca2+ release from internal stores) were significantly increased in aortas from male and female DOCA-salt compared to control aortas. DOCA-salt treatment of male, but not female, rats statistically increased vascular mRNA expression of ET-1 and ET B receptors, but decreased the expression of ET A receptors. Molecular up-regulation of vascular ET B receptors, rather than differential changes in smooth muscle Ca2+ handling mechanisms, seems to account for the increased vascular reactivity to ET-1/ET B receptor agonists and higher blood pressure levels observed in male DOCA-salt rats.

Gender-related differences in the effects of nitric oxide donors on neuroleptic-induced catalepsy in mice

It has been suggested that nigrostriatal dopaminergic transmission is modulated by nitric oxide (NO). Since there is evidence that gonadal hormones can affect extrapyramidal motor behavior in mammals, we investigated the effects of isosorbide dinitrate (ISD), linsidomine (SIN-1) and S-nitroso-N-acetylpenicillamine (SNAP), three pharmacologically different NO donors, on neuroleptic-induced catalepsy in 60- to 80-day-old male and female albino mice. Catalepsy was induced with haloperidol (1 mg/kg, ip) and measured at 30-min intervals by means of a bar test. Drugs (or appropriate vehicle) were injected ip 30 min before haloperidol, with each animal being used only once. ISD (5, 20 and 50 mg/kg) caused a dose-dependent inhibition of catalepsy in male mice (maximal effect 120 min after haloperidol: 64% inhibition). In the females only at the highest dose of ISD was an attenuation of catalepsy observed, which was mild and short lasting. SIN-1 (10 and 50 mg/kg) did not significantly affect catalepsy in female mice, while a significant attenuation was observed in males at the dose of 50 mg/kg (maximal inhibition: 60%). SNAP (20 mg/kg) significantly attenuated catalepsy in males 120 min after haloperidol (44% inhibition), but had no significant effect on females. These results basically agree with literature data showing that NO facilitates central dopaminergic transmission, although the mechanisms are not fully understood. They also reveal the existence of gender-related differences in this nitrergic modulation in mice, with females being less affected than males.

Dipeptidyl peptidase IV (CD26) activity in the hematopoietic system: differences between the membrane-anchored and the released enzyme activity

Dipeptidyl peptidase IV (DPP-IV; CD26) (EC 3.4.14.5) is a membrane-anchored ectoenzyme with N-terminal exopeptidase activity that preferentially cleaves X-Pro-dipeptides. It can also be spontaneously released to act in the extracellular environment or associated with the extracellular matrix. Many hematopoietic cytokines and chemokines contain DPP-IV-susceptible N-terminal sequences. We monitored DPP-IV expression and activity in murine bone marrow and liver stroma cells which sustain hematopoiesis, myeloid precursors, skin fibroblasts, and myoblasts. RT-PCR analysis showed that all these cells produced mRNA for DPP-IV. Partially purified protein reacted with a commercial antibody to CD26. The K M values for Gly-Pro-p-nitroanilide ranged from 0.43 to 0.98 mM for the membrane-associated enzyme of connective tissue stromas, and from 6.76 to 8.86 mM for the enzyme released from the membrane, corresponding to a ten-fold difference, but only a two-fold difference in K M was found in myoblasts. K M of the released soluble enzyme decreased in the presence of glycosaminoglycans, nonsulfated polysaccharide polymers (0.8-10 µg/ml) or simple sugars (320-350 µg/ml). Purified membrane lipid rafts contained nearly 3/4 of the total cell enzyme activity, whose K M was three-fold decreased as compared to the total cell membrane pool, indicating that, in the hematopoietic environment, DPP-IV activity is essentially located in the lipid rafts. This is compatible with membrane-associated events and direct cell-cell interactions, whilst the long-range activity depending upon soluble enzyme is less probable in view of the low affinity of this form.

Profitability differences between online and offline retailers -An empirical study on European SMEs

Tämän pro gradu tutkielman tarkoituksena oli selvittää jos ja miten kannattavuus eroaa verkko- ja kivijalkakauppojen välillä. Lisäksi pyrittiin selvittämään onko näiden erojen syitä mahdollista selvittää yritysten taloudellisten tunnuslukujen avulla. Tutkielma koostuu kirjallisuuskatsauksesta ja kvantitatiivisesta tutkimuksesta. Kirjallisuuskatsaus antaa yleiskuvan siitä miten verkkokaupan toiminta eroaa kivijalkaliikkeen toiminnasta ja mitkä ovat näistä eroista koituvat hyödyt ja yleisimmät sudenkuopat. Kvantitatiivisessa tutkimuksessa käytetään Amadeus tietokannasta kerättyjä taloudellisia tietoja Eurooppalaisista verkko- ja kivijalkakaupoista. Tutkimuksessa löydettiin tilastollisesti merkitseviä eroja verkko- ja kivijalkakauppojen kannattavuudessa. Verkkokauppojen todettiin olevan kivijalkakauppoja kannattavampia, mutta taloudellisten tunnuslukujen tilastollisella analysoinnilla ei kyetty löytämään yksittäisiä selittäviä tekijöitä näille eroille.

Differences in pressure and temperature transitions of proteins and polymer gels

Pressure-driven and temperature-driven transitions of two thermoresponsive polymers, poly(N-isopropylacrylamide) (pNIPAM) and poly(N-vinylisobutyramide) (pNVIBA)), in both a soluble linear polymer form and a cross-linked hydro-gel form, were examined by a dynamic light-scattering method and direct microscopic observation, respectively. Their behavior was compared with that of protein systems. Changes in some characteristic parameters in the time-intensity correlation functions of dynamic light-scattering measurement of aqueous solutions of pNIPAM at various pressures and temperatures showed no essential differences during temperature and pressure scanning and, as a whole, the motions of polymers in aqueous solutions were similar in two types of transitions until chain shrinkage occurred. The gels (cross-linked polymer gels) prepared from the thermoresponsive polymers also showed similar volume transitions responding to the pressure and temperature increase. In temperature transitions, however, gels showed drastic volume shrinkage with loss of transparency, while pressure-induced transition showed a slow recovery of transparency while keeping the size, after first transient drastic volume shrinkage with loss of transparency. At a temperature slightly higher than the transition under atmospheric temperature, so-called reentry of the volume change and recovery of the transparency were observed during the pressure-increasing process, which implies much smaller aggregation or non-aggregated collapsed polymer chains in the gel at higher pressures, indicating a certain mechanistic difference of the dehydration processes induced by temperature and pressure.