Highly porous multiwalled carbon nanotube buckypaper using electrospun polyacrylonitrile nanofiber as a sacrificial material.

Polyacrylonitrile (PAN) was solubilized in N,N-dimethyl formamide (DMF) and the electrospinning process has been employed to obtain PAN nanofibers (PF). Multiwalled carbon nanotubes (MWCNT) were dispersed with the aid of Triton X-100 surfactant and subsequently centrifugated. Buckypapers (BP/PF) were prepared by vacuum filtration procedure of MWCNT suspension supernatant stacking four PF layers over a nylon membrane. The PF removal was carried out by immersing the BP/PF system in DMF and removal periods of 10 and 30 min were evaluated. Scanning electron microscopy (SEM) has not shown any PAN residue in the MWCNT network resulting in highly porous BP. However, by Fourier transform infrared spectroscopy (FT-IR) a PAN band was found around of 2243 cm-1 corresponding to nitrile group (C≡N). Besides, PAN leftover was evidenced by thermogravimetric analysis (TGA), high-resolution transmission electron microscopy (HR-TEM), electrical characterization through four-point probe, nitrogen adsorption at 77 K, and X-ray diffraction (XRD).

Biomimetic calcium phosphate coating on Ti-7.5Mo alloy for dental application.

Titanium and its alloys have been used as bone-replacement implants due to their excellent corrosion resistance and biocompatibility. However, a titanium coating is a bioinert material and cannot bond chemically to bone tissue. The objective of this work was to evaluate the influence of alkaline treatment and heat treatment on the formation of calcium phosphate layer on the surface of a Ti-7.5Mo alloy after soaking in simulated body fluid (SBF). Thirty six titanium alloy plates were assigned into two groups. For group I, samples were immersed in a 5.0-M NaOH aqueous solution at 80°C for 72 h, washed with distilled water and dried at 40°C for 24 h. For group II, after the alkaline treatment, samples were heat-treated at 600°C for 1 h in an electrical furnace in air. Then, all samples were immersed in SBF for 7 or 14 days to allow the formation of a calcium phosphate coating on the surface. The surfaces were characterized using SEM, EDS, AFM and contact angle measurements.

Ageing down-modulates liver inflammatory immune responses to schistosome infection in mice.

Ageing is associated with several alterations in the immune system. Our aim in this study was to compare the development of immunity to Schistosoma mansoni infection in young versus aged C57Bl/6 mice using the liver as the main organ to evaluate pathological alterations and immune responses. In the acute phase, young mice had large liver granulomas with fibrosis and inflammatory cells. Chronic phase in young animals was associated with immunomodulation of granulomas that became reduced in size and cellular infiltrate. On the other hand, aged animals presented granulomas of smaller sizes already in the acute phase. Chronic infection in these mice was followed by no alteration in any of the inflammatory parameters in the liver. In concert with this finding, there was an increase in activated CD4+ T, CD19+ B and NK liver cells in young mice after infection whereas old mice had already higher frequencies of activated B, NK and CD4+ T liver cells and infection does not change these frequencies. After infection, liver production of inflammatory and regulatory cytokines such as IFN-gamma, IL-4 and IL-10 increased in young but not in old mice that had high levels of IL-4 and IL-10 regardless of their infection status. Our data suggest that the unspecific activation status of the immune system in aged mice impairs inflammatory as well as regulatory immune responses to S. mansoni infection in the liver, where major pathological alterations and immunity are at stage. This poor immune reactivity may have a beneficial impact on disease development.

A new antibacterial clerodane diterpenoid from the resinous exudate of Haplopappus uncinatus.

The antibacterial activity of Haplopappus uncinatus is attributed to a new clerodane diterpenoid, 18-acetoxy-cis-cleroda-3-en-15-oic acid (10 betaH, 16 xi 19 beta, 17beta, 20 alpha form) (1), isolated as a major component from the resinous exudates of its twigs and leaves, together with the inactive 3,5-dihydroxy-6,7,3',4'-tetramethoxyflavone, n-alkanes and a few sesquiterpenoids.

Merocyanine-type dyes from barbituric acid derivatives.

The preparation and the solvatochromic behavior of two dyes, obtained by condensation of N,N'-dimethylbarbituric acid with dimethylaminobenzaldehyde and with 4,4'-bis(N,N-dimethylamino)benzophenone (Michler's ketone) are described. The latter dye is rather sensitive to the polarity of the medium, and in particular, to the hydrogen-bond-donor ability of protic solvents. The solvatochromism of both compounds is discussed in terms of the pi* and E(T)(30) solvent polarity scales and their differences in behavior interpreted with the aid of semiempirical calculations.

Variation of the antimicrobial activity of Pseudognaphalium vira vira (Asteraceae): isolation and X-ray structure of ent-3beta-hydroxy-16-kauren-19-oic acid.

The antimicrobial properties of the resinous exudate from twigs and leaves of a population of Pseudognaphalium vira vira were re-examined against five Gram positive bacteria. The observed decrease in the antimicrobial activity might reflect a change in the diterpenoid composition of the exudate. The title compound 2 was isolated in substantial amount, together with ent-16-kauren-19-oic acid (1), and its structure determined by X-ray diffraction analysis.

Protective effect of aminoguanidine in a murine model of pulmonary fibrosis induced by bleomycin.

Aminoguanidine is a drug known for more than a century, which has been attracting increasing interest in recent years due to the discovery of new pharmacological properties. This study investigated the effects of aminoguanidine on the fibrotic response induced by intratracheal administration of bleomycin to rats. Three groups of animals were studied: Group A (n = 19) corresponded to the control group. Group B (n = 20) received 10 IU/kg bleomycin intratracheal, and Group C (n = 12) received the same amount of bleomycin as Group B followed by 50 mg/kg/day aminoguanidine bicarbonate for 4 weeks. Aminoguanidine led to significant reductions in total hydroxyproline content of the lungs in Group C compared to Group B (Group A: 1.83+/-0.14 mg x Group B: 3.46+/-0.36 mg x Group C: 2.09+/-0.22 mg). Morphometric collagen studies carried out on histological sections stained with Sirius red F3BA showed that aminoguanidine promoted a significant reduction of the area occupied by collagen in the axial and septal zones of the lungs (Axial region = Group A: 4.29+/-1.31% x Group B: 19.30+/-4.86% x Group C: 8.52+/-1.96%; Septal region = Group A: 0.15+/-0.06% x Group B: 0.61+/-0.21% x Group C: 0.15+/-0.06%). These results suggest that aminoguanidine is a potential therapeutic agent for the treatment and prevention of pulmonary fibrosis which is associated with different clinical conditions.

Alpha 1-adrenergic and 5-HT2-serotonergic effects of some beta-alkoxy-beta-phenylethylamines on isolated rat thoracic aorta.

1. Ten racemic beta-alkoxy-beta-phenylethylamines were found to elicit concentration-dependent contraction of the isolated rat thoracic aorta with apparent pD2 values in the 4.56-6.76 range. With one exception, which produces the same maximal contraction (Emax) as serotonin (5-HT), the Emax values attained with these compounds are lower than those produced by either 5-HT or norepinephrine (NE). 2. Pretreatment with either prazosin or ketanserin (10(-8) M) leads in most cases to decreased Emax values and slopes in the dose-response curves. Apparent serotonergic (pD2S) and adrenergic (pD2A) pD2 values going from 4.22 to 6.08 (pD2S) and from 3.87 to 5.27 (pD2A) were calculated from results obtained in the presence of prazosin or ketanserin, respectively. 3. In the 10(-7)-10(-5) M range, and in contrast with the results obtained with the previous compounds, BON [(+/-)-2-(2,5-dimethoxy-4-nitrophenyl)-2-methoxy-ethylamine] behaves as an antagonist to both 5-HT and NE (apparent pA2 = 7.08 and 7.45, respectively) in this preparation.

Incidência de parasitoses em escolares da Escola Municipal de Educaçäo Infantil "Sant'Ana Itatiaia", Juiz de Fora-MG e sua possível correlaçäo com a qualidade da água para consumo / Parasitosis incidence in children from EMEI \"Sant'Ana Itatiaia\", Juiz de Fora-MG, Brazil and possible relationship with the presence of the parasites in source of water

SÄo apresentados os resultados de 23 exames parasitológicos de fezes coletadas com conservador MIF e analisadas pelo método preconizado por Hoffman, Pons & Janer no Laboratório de Saúde Pública/FFB/UFJF e, de 9 análises bacteriológicas da água consumida na residência de 7 escolares da EMEI "Sant'Ana Itatiaia" - Juiz de Fora - MG, segundo a metodologia empregada no Laboratório de Análise de Alimentos e Saneamento de Aguas/FFB/UFJF. O estudo foi desenvolvido nos meses de Agosto a Outubro de 1994 em escolares com idade entre 4 e 6 anos e de ambos os sexos. A percentagem das amostras de fezes positivas foi de 56,52 porcento e a de negativas de 43,48 porcento. A etiologia das enteroparasitoses de maior incidência na populaçäo estudada foi: Entamoeba coli (38,89 porcento), Ascaris lumbricoides (27,78 porcento), Trichuris trichiura (11,11 porcento), Giardia lamblia (11,11 porcento) e Entamoeba histolytica (11,11 porcento). Das amostras analisadas, 17,39 porcento revelaram a presença de mais de um parasita. Apesar de näo ter sido possível correlacionar a etiologia das enteroparasitoses com uma provável veiculaçäo hídrica das mesmas, verificou-se que 61,11 porcento das amostras de fezes examinadas revelaram a presença de protozoários e, ainda, que 60 porcento das amostras de água oriundas de outras fontes que näo o abastecimento público, foram consideradas impróprias para o consumo como bebida. Tais dados reforçam a necessidade de medidas administrativas eficientes para a implantaçäo e melhoria do saneamento básico, pois näo existe saúde sem infra-estrutura sanitária

Effects of fibrin adhesive material (Tissucol) on alveolar healing in rats under stress.

The effects of Tissucol on alveolar healing following stress were evaluated histologically, comparing three groups of 28 male albino rats each. Stress was applied and their right upper incisors were extracted. Group A served as an empty control site. In Group B, Tissucol was applied into the alveolar cavity. Group C received local antifibrinolytic treatment (alveolar irrigation with epsilon-aminocaproic acid solution) before implant of Tissucol into the tooth socket. Four animals in each group were killed at 1, 3, 6, 9, 15, 21 and 24 days after surgery. Results showed that: 1) Tissucol did not interfere with connective and osseous tissue formation; 2) Tissucol allowed new bone formation; 3) Tissucol residues in Group B in sections of 24-day specimens did not impair healing; 4) Tissucol was usually completely resorbed and healing was complete 24 days after surgery in Group C.

Osseous regeneration in the presence of fibrin adhesive material (Tissucol) and epsilon-aminocaproic acid (EACA).

The effects of Tissucol and Tissucol/EACA on bone healing were evaluated histologically. Experimental defects were made in both tibias of 25 rats. Test materials were placed in defects in right tibias and left tibias served as control. Five animals in each group were killed at 1, 3, 7, 14 and 21 days after surgery. Results showed that: a) Tissucol did not interfere with connective and osseous tissue formation; b) Tissucol allowed new bone formation; c) Tissue residues in Tissucol groups in sections of 21-day specimens did not impair healing; d) Tissucol/EACA was usually completely resorbed and healing was complete 21 days after surgery in the Tissucol/EACA group.

Interference of the blood clot on granulation tissue formation after tooth extraction. Histomorphological study in rats.

The interference of a blood clot in the first postoperative hours of dental extraction wounds was studied in rats. Sixty male albino rats were divided into two groups: Group I, immediately after extraction of right maxillary incisor the gingival mucosa was approximated and sutured; Group II, after 6 to 8 minutes postoperatively the blood clot was removed with saline irrigation and absorbent paper cones. The mucosa was then approximated and sutured. Six animals in each group were sacrificed after 12 hours, 1, 4, 7 and 10 days. There was a profound delay in healing in Group II since, although a new blood clot was later formed, it was not organized. The quality and the constitution, maintenance and retraction of the clot are the regulating factors in connective tissue formation during alveolar healing.