On the excitation dependence of fluorescence spectra of meso-tetrapyridyl zinc (II) porphyrin and its relation with hydrogen bonding and outlying decoration.

Zinc porphyrins are potential candidates for boosting the advancement of various technological applications, including those exploring the molecule's radiative emissions. In this work, the excitation dependence of fluorescence spectra from 5,10,15,20-meso-tetrapyridyl zinc(II) porphyrin dissolved in a binary solvent mixture of CHCl3: MeOH, is reported. Important modifications in the profiles of the fluorescence bands are observed after exciting the molecules in a broad wavelength range from 350 to 565 nm. We attribute such modifications to the existence of two distinct relaxation pathways, related to two quasi-degenerated potential energy surfaces (PES) in the ZnTPyP's first excited state whose population rates changes for different excitation wavelengths. We also observed that by changing the CHCl3:MeOH proportion in the binary mixture, a quenching mechanism mediated by the MeOH hydrogen bondings and ZnTPyP takes place, which allows for tuning the excitation dependence of the aforementioned relaxations pathways. Moreover, our data confirm that the addition of outlying RuCl(dppb)(bipy) ruthenium complex linked to the pyridyl moieties of the ZnTPyP ring is also an excellent strategy to modify the excitation dependence of the fluorescence relaxation pathways.

Evolution of electronic and vibronic transitions in metal(II) meso-tetra(4-pyridyl)porphyrins.

The changing of the electronic and vibronic states due to the insertion of Zn(II), Cu(II), Ni(II) or Co(II) ions in the meso-tetrakis(4-pyridyl)porphyrin ring center is investigated. The combination of absorption, photoluminescence, Raman and infrared spectroscopies with second-derivative-based spectral deconvolution analysis reveals that the structuration of both B- and Q-bands is very sensitive to the decorating ion. Similar to free base porphyrins, metal(II) meso-tetra(4-pyridyl)porphyrins also present their Q-band constituted of multiple electronic transitions, where the central ion plays an important role in the selection of vibration modes that mediate the vibronic transitions. Our novel results will expand and reinterpret current assignments for metal(II) meso-tetra(4-pyridyl)porphyrins vibrational modes available in the literature.

Accuracy of qPCR for quantifying Leishmania kDNA in different skin layers of patients with American tegumentary leishmaniasis.

OBJECTIVES: Superficial swab sampling of American tegumentary leishmaniasis (ATL) lesions shows higher amounts of Leishmania than those from biopsy. Subcutaneous involvement is also important in ATL, but parasite quantification according to lesion depth has not been evaluated. We aim to present the best depth at which sampling should be performed for molecular exams of ATL. METHODS: Patients with a clinical presentation compatible with ATL were allocated to ATL and control groups. Qualitative and quantitative qPCR assays were performed using SYBR Green and primers amplifying the kDNA minicircle of Leishmania spp. in different skin layers, including the epidermis, the superior dermis, the inferior dermis, and the hypodermis. RESULTS: Fifty-nine patients were included in this study, including 40 who had been diagnosed with ATL and 19 controls. The number of parasites was greater in samples of the epidermis and superior dermis (159.1 × 106, range 4.0-781.7, and 75.4 × 106, range 8.0-244.5, mean Leishmania parasite equivalents per µg of tissue DNA, respectively) than those in samples of the inferior dermis and hypodermis (54.6, range 8.0-256.6, and 16.8 × 106, range 8.0-24.1, mean Leishmania parasite equivalents per µg of tissue DNA, respectively). The best diagnostic accuracy was achieved in the superior dermis (77.9%) and was significantly greater than that in the hypodermis (63.3%; p 0.039). CONCLUSIONS: We conclude that superficial sampling can retrieve a greater quantity of parasites. Future studies of the role of transepidermal elimination as a mechanism of host defence in ATL must be performed as there is a considerable quantity of Leishmania kDNA in the epidermis.

Novel insights on the vibronic transitions in free base meso-tetrapyridyl porphyrin.

We present novel results on the free base 5,10,15,20-meso-tetra(pyridyl)-21H,23H-porphyrin (H2TPyP). This molecule presents complex electronic and vibrational properties and despite the vast literature reporting the transitions observed in its absorption and fluorescence spectra, a more accurate interpretation has been kept elusive. In particular, we show that the molecule's Q-band develops into many electronic and vibronic transitions, whose the well-known "four orbital model" finds it difficult to reconcile. Using distinct spectroscopy techniques, we conclude that both Qx- and Qy-bands comprise, in fact, two quasi-degenerated electronic states together with their respective vibronic progressions each. The analysis of the Huang-Rhys factors and complementary time- and polarization-resolved measurements reinforce the need for the proposed Q-band multi features remodeling.

Contrasting photophysical properties of rhenium(i) tricarbonyl complexes having carbazole groups attached to the polypyridine ligand.

In the present work, new rhenium(i) polypyridyl compounds, fac-[Re(L)(CO)3(cbz2phen)](+/0) where cbz2phen = 4,7-di(9H-carbazol-9-yl)-1,10-phenanthroline and L = Cl(-), pyridine (py) or 2-aminomethylpyridine (ampy) were synthesized and characterized by (1)H NMR, UV-Vis and IR spectroscopy combined with theoretical calculations using time-dependent density functional theory (TD-DFT). Their photophysical properties were investigated by steady state and time-resolved emission spectroscopy. These compounds show a strong and broad absorption band around 350-500 nm that, also by TD-DFT, corresponds to the carbazol → phenanthroline intraligand charge transfer transition, (1)ILCTcbz2phen, with some contribution of the Re(i) → phenanthroline metal-to-ligand charge transfer transition, (1)MLCTRe→cbz2phen. In contrast to typical Re(i) polypyridyl complexes, cbz2phen-based Re(i) compounds exhibit two emission maxima in CH3CN solution and relatively low emission quantum yields, 10(-3)-10(-2). Solution phase time-resolved photoluminescence and excited state quenching experiments provided meaningful information on the presence of multiple emitter states after light excitation, which were identified as an (1)ILCTcbz2phen excited state deactivation at higher energies and a long-lived phosphorescence attributed to the (3)MLCTRe→cbz2phen excited state. When embedded into a PMMA matrix, the radiative decay from the singlet state is inhibited and the contribution of both (3)MLCT and (3)ILCTcbz2phen to the luminescence is observed. The photophysics of these Re(i) compounds reported herein provide new insights into the understanding of substitutional groups on the polypyridyl ligands that are relevant to practical and fundamental development of photo-induced molecular devices.

The influence of treatment on the development of leishmaniasis recidiva cutis: a 17-year case-control study in Midwestern Brazil.

BACKGROUND: The recurrence of American cutaneous leishmaniasis (ACL) in patients experiencing a long-term cure is often called leishmaniasis recidiva cutis (LRC). LRC is considered an unusual form of ACL. OBJECTIVE: This study aims to estimate the incidence of LRC in ACL patients evaluated at a tertiary dermatologic centre in Midwestern Brazil. We also aim to evaluate the association between various treatment regimens and the development of LRC using multivariate analysis in a case-control study. METHODS: We performed a 17-year epidemiological study using data from patients treated at our dermatologic centre from July 1994 to December 2011. A retrospective analysis was then performed to estimate risk and protective factors related to clinical presentation. We also assessed the influence of treatment regimens in the development of LRC. RESULTS: The incidence of LRC among ACL patients was 1.34%. The analysis included 105 patients; 82 patients (78%) were in the control group, and 23 patients (22%) were in the LRC case group. The data analysis indicated that the standard treatment N-methylglucamine antimoniate (N-MA) reduced the development of LRC in bivariate (odds ratio (OR) = 0.34; 95% CI = 0.13-0.91) and multivariate analyses (OR = 0.16; 95% CI = 0.03-0.86; P = 0.03). However, no differences in LRC incidence were observed when the standard treatment N-MA and alternative drugs, such as pentamidine and amphotericin B, were considered (OR = 0.47; 95% CI = 0.16-1.35) CONCLUSION: We conclude that the standard treatment N-MA, as proposed by the Brazilian Ministry of Health, is effective in the prevention of LRC. Although other drugs have shown promising results in LRC, more scientific evidence is needed to assess their efficacy compared with N-MA.

The photophysics of fac-[Re(CO)3(NN)(bpa)](+) complexes: a theoretical/experimental study.

The influence of the polypyridyl ligand on the photophysics of fac-[Re(CO)3(NN)(bpa)](+), bpa = 1,2-bis-(4-pyridyl)ethane and NN = 1,10-phenanthroline (phen), pyrazino[2,3-f][1,10]-phenanthroline (dpq), and dipyrido[3,2-a:2'3'-c]phenazine (dppz) has been investigated by steady state and time-resolved emission spectroscopy combined with theoretical calculations using time-dependent density functional theory (TD-DFT). The fac-[Re(CO)3(phen)(bpa)](+) is a typical MLCT emitter in acetonitrile with ϕ = 0.11 and τ = 970 ns. The emission lifetime and quantum yield decrease significantly in fac-[Re(CO)3(dpq)(bpa)](+) (ϕ = 0.05; τ = 375 ns) due to the presence of a close lying dark charge transfer state located at the pyrazine ring of dpq, as indicated by TD-DFT data. The luminescence of these complexes is quenched by hydroquinone with kq = (2.9 ± 0.1) × 10(9) and (2.6 ± 0.1) × 10(9) L mol(-1) s(-1), respectively, for NN = phen or dpq. These values are increased respectively to (4.6 ± 0.1) × 10(9) and (4.2 ± 0.1) × 10(9) L mol(-1) s(-1) in the 1 : 1 H2O-CH3CN mixture. In this medium Stern-Volmer constants determined by steady-state and time-resolved measurements differ from each other, which is indicative of static quenching, i.e. the pre-association of hydroquinone and the complexes through hydrogen bonding between the remote N-atom in the bpa ligand (KA ≅ 1-2 × 10(1) L mol(-1)), followed by a concerted proton-electron transfer. In contrast to other investigated complexes, fac-[Re(CO)3(dppz)(bpa)](+) is weakly emissive in acetonitrile at room temperature (ϕ ≅ 10(-4)) and does not exhibit a rigidochromic effect. This photophysical behaviour as well as TD-DFT data indicate that the lowest lying triplet excited state can be described as (3)ILdppz. The results provide additional insight into the influence of the polypyridyl ligand on the photophysical properties of Re(I) complexes.

A pilot study comparing low-dose liposomal amphotericin B with N-methyl glucamine for the treatment of American cutaneous leishmaniasis.

BACKGROUND: Cutaneous leishmaniasis is an infectious re-emerging disease that has increased in incidence worldwide. Antimony, a highly toxic drug, remains the first choice therapy to treat it. Liposomal amphotericin B is active against Leishmania and is less toxic than antimony. OBJECTIVE: To compare low-dose liposomal amphotericin B with N-methyl glucamine for the treatment of American cutaneous leishmaniasis. PATIENTS/METHODS: In a controlled open-label trial 35 patients with a localized form of American cutaneous leishmaniasis were included. They were allocated to a first group treated with 1.5 mg/kg/day of liposomal amphotericin B for 5 days, or to a second one treated with 20 mgSbV/kg/day of N-methyl glucamine for 20 days. RESULTS: In the first group, 50% and 81% of patients experienced a clinical cure and clinical improvement respectively. There was a 100% clinical cure in the second group. CONCLUSION: Liposomal amphotericin B seems to be promising and safe for the treatment of American cutaneous leishmaniasis.

Investigation of ground- and excited-state photophysical properties of 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphyrin with ruthenium outlying complexes.

The present work employs a set of complementary techniques to investigate the influence of outlying Ru(II) groups on the ground- and excited-state photophysical properties of free-base tetrapyridyl porphyrin (H(2)TPyP). Single pulse and pulse train Z-scan techniques used in association with laser flash photolysis, absorbance and fluorescence spectroscopy, and fluorescence decay measurements, allowed us to conclude that the presence of outlying Ru(II) groups causes significant changes on both electronic structure and vibrational properties of porphyrin. Such modifications take place mainly due to the activation of nonradiative decay channels responsible for the emission quenching, as well as by favoring some vibrational modes in the light absorption process. It is also observed that, differently from what happens when the Ru(II) is placed at the center of the macrocycle, the peripheral groups cause an increase of the intersystem crossing processes, probably due to the structural distortion of the ring that implies a worse spin-orbit coupling, responsible for the intersystem crossing mechanism.

Leishmania (Viannia) braziliensis is the main species causing cutaneous leishmaniasis in the Federal District of Brazil

The first autochthonous case of American cutaneous leishmaniasis was reported in the Federal District in 1980, and the species involved in this type of leishmaniasis was unknown. This study aimed to identify the species that causes the disease in the Federal District and to investigate its clinical and epidemiological aspects. Between 2000 and 2007, 71 autochthonous cases of leishmaniasis were reported in the Federal District. Leishmania species were identified by means of direct immunofluorescence reactions using monoclonal antibodies and restriction fragment length polymorphism. The species of 40 (56.33%) out of 71 samples were identified. Thirty-six (90%) were identified as Leishmania (Viannia) braziliensis and four (10%) were identified as Leishmania (Leishmania) amazonensis. In this area, the disease had clinical and epidemiological characteristics similar to those found in other Brazilian regions.

DNA identification of Leishmania (Viannia) braziliensis in human saliva from a patient with American cutaneous leishmaniasis

This study aims to report the amplification of the DNA of Leishmania (V.) braziliensis, using polymerase chain reaction, obtained from the saliva of a patient with American cutaneous leishmaniasis who did not present any lesion in the oral mucosa. Amplification produced fragments of 103 bp, an estimated size employing Leishmania (V.) braziliensis primers (b1 e b2). The present results revealed, for the first time, that the in vitro amplification of Leishmania DNA using samples from the salivary fluid of a patient with American cutaneous leishmaniasis is possible. However, more studies are required with a larger number of participants to evaluate the usefulness of saliva as a non-invasive sample for PCR. The development of such non-invasive technique is necessary for the diagnosis of many diseases in the future, especially infectious and parasitic ones.

Foxp3 expression in lesions of the different clinical forms of American tegumentary leishmaniasis.

As the diversity in clinical presentation of American tegumentary leishmaniasis (ATL) is determined mainly by the immune response of host, our aim was to evaluate the in situ expression of Foxp3 [marker of regulatory T (Treg) cell] in lesions of the different clinical forms of ATL. Foxp3(+) cells were observed in 39.5% (32/81) of the samples and the number of positive cells was low in all the clinical forms. Even presenting a significantly lower number of CD4(+) T cells, diffuse cutaneous leishmaniasis (DCL) showed a higher expression of Foxp3 when compared with localized cutaneous leishmaniasis (LCL) and mucocutaneous leishmaniasis (MCL). In LCL and MCL, the number of Foxp3(+) cells correlated positively with the number of apoptotic cells (active caspase-3(+) cells). A positive correlation was also observed between the expression of active caspase-3 and FasL in these clinical forms. Our data suggest that increased number of Treg cells may be associated to the hyporesponsiveness observed in DCL and also indicate that the apoptosis may be a possible mechanism of action of Foxp3(+) Treg cell in LCL and MCL. However, further studies are required to better understand the mechanism of action of Treg cell.

Inefficacy of the association N-methyl glucamine and topical miltefosine in the treatment of experimental cutaneous leishmaniasis by Leishmania (Leishmania) amazonensis

Pentavalent antimonial (SbV) is the first treatment for cutaneous leishmaniasis (CL). Other drugs present similar side effects and higher cost. Oral miltefosine is effective to treat kala-azar. The aim of the present study was to compare the efficacy of glucamine (SbV) plus topical miltefosine with glucamine in the treatment of CL. Eighty isogenic C57BL/6 mice were inoculated with Leishmania (Leishmania) amazonensis and divided into two groups: one group was treated with SbV associated with miltefosine, and the other group received SbV plus saline solution. Groups were evaluated according to the diameter of the inoculated foot pad, the culture, and the parasite count using the limiting dilution assay. There was not statistical difference. The efficacy of glucamine in CL treatment did not increase when associated with topical miltefosine.(AU)

Use of Cavia porcellus (Guinea Pigs) as an experimental model for Leishmania (Viannia) braziliensis

Laboratory animals are fundamental to study immunological aspects and the efficacy of new drugs to treat leishmaniasis. However, we do not have practical and good animal models to study leishmaniasis caused by Leishmania (Viannia) braziliensis - L(V)b. In this study, thirty-two experimental animals (Cavia porcellus) were injected in the hind foot with 3x105 promastigote forms of L(V)b. The animals were followed for eight weeks. None of the experimental animals developed lesions or presented the parasite in any of the tests performed (histopathological exam, smears, culture, inoculation in hamsters, and polymerase chain reaction)

Sensitivity of a vacuum aspiratory culture technique for diagnosis of localized cutaneous leishmaniasis in an endemic area of Leishmania (Viannia) braziliensis transmission.

Sixty eight patients with localized cutaneous leishmaniasis from an area with Leishmania (Viannia) braziliensis transmission had cultures performed with a modified Marzochís vacuum aspiratory puncture technique to establish sensitivity and contamination rate with this new method. Overall sensitivity of three aspirates was 47.1%; (CI95% 39.4; 59.4) significantly greater than the sensitivity of a single one aspirate. Fungal contamination was observed in 6/204 (2.9%) inoculated culture tubes. We recommend that this useful technique should be adopted as routine for primary isolation of L. (V.) braziliensis from localized cutaneous ulcers.

Sensitivity of lymph node aspiration in localized cutaneous leishmaniasis due to Leishmania (Viannia) braziliensis.

Twenty nine patients with localized cutaneous leishmaniasis had lymph node and skin ulcer aspirations for culture of Leishmania with the modified Marzochís vacuum aspiratory technique. Sensitivity of lymph node aspiration was 58.6% and 34.5% for skin ulcer aspiration (P=0.06). Combined sensitivity of the two methods was 79.3%. There was no agreement between methods (Kappa Index = -0.084; CI95% -0,45; 0,28) showing the potential complementary roles in diagnostic approach.

[American cutaneous leishmaniasis in the Federal District]. / Leishmaniose tegumentar americana no Distrito Federal.

In the present study, we report 11 cases of mucocutaneous leishmaniasis (MCL) in patients living in the Federal District who had not left their area of residence for a period ranging from six months to two years before the onset of the disease. Six of the eleven patients live in the suburban town of Planaltina. All showed a positive Leishmanin intradermal reaction. Ten of them presented the parasite in their lesions. Leishmania (V) braziliensi was identified in the lesions of two patients by the monoclonal antibody method. Nine patients were treated with pentavalent antimoy and two with pentamidine. Relapse occurred in two cases after treatment with antimony. In view of the detection of vectors and infected patients in the Federal District, it is probable that Leishmania infection is occurring in Brasilia and its suburban areas.

Clinical observations of unresponsive mucosal leishmaniasis.

We report the long-term clinical follow-up of two patients with unresponsive mucosal leishmaniasis due to Leishmania (Viannia) braziliensis from the Três Braços area in Bahia State, Brazil. Both were agricultural male workers with extensive upper respiratory mucosal involvement that was not cured with conventional and experimental therapy.

Avaliação da tolerância e nefrotoxicidade do antimonial pentavalente administrado na dose de 40 mg Sb V/kg/dia, de 12/12 h, por 30 dias na forma cutâneo-mucosa de leishmaniose / The evaluation of the tolerance and nephrotoxicity of pentavalent antimony administered in a dose of 40 mg Sb V/kg/day, 12/12 hr, for 30 days in the mucocutaneous form of leishmaniasis

Foi avaliada a função renal de 11 pacientes com leishmaniose cutâneo-mucosa tratados com antimonial pentavalente na dose de 40mg SbV/kg/dia aplicada de 12/12 horas, em esquema contínuo, durante trinta dias. No estudo, um paciente apresentou insuficiência renal reversível e dois desenvolveram alterações enzimáticas hepáticas e eletrocardiográficas sendo o esquema terapêutico interrompido. Nos demais pacientes observou-se efeitos nefrotóxicos tais como diminuição da taxa de filtração glomerular, diminuição da capacidade de concentração urinária, avaliada por um jejum hídrico de 16 horas e aumento na fração de excreção de sódio. No exame do sedimento urinário observou-se um aumento no número de leucócitos e cilindros. Os resultados encontrados neste estudo sugerem que o tratamento com antimonial pentavalente na dose de 40mg SbV/kg/dia foi menos tolerado em virtude de seus efeitos tóxicos, não parecendo apresentar índice de cura superior ao esquema atualmente preconizado de 20mg SbV/kg/dia.

The renal function of eleven patients with mucocutaneous leishmaniasis was analyzed in a prospective study realized at the School Hospital of University of Brasília. The patients were treated with doses of 40 mg/kg/day of pentavalent antimony (Sb V), in a continuous scheme during thirty days. In this study three patients were excluded, one patient with reversible renal failure and two patients with hepatic and cardiac malfunctions. In the other eight patients, severe nephrotoxic effects were observed, like reduction of glomerular filtration rate, reduction of the urinary concentration capacity, evaluated by a sixteen hours hydric fasting and an increase of sodium fractional excretion. An increase in the number of leucocytes and cylinders were observed at the urinary sediment exam. Finally, the results shows that the treatment with pentavalent antimony in doses of 40 mg Sb/kg/day was less tolerated on account of its renal toxic effects. This scheme seems not be superior than the currently preconized scheme of 20 mg of Sb V/kg/day during 30 days.