Physicochemical and Biological Evaluation of Curdlan-Poly(Lactic-Co-Glycolic Acid) Nanoparticles as a Host-Directed Therapy Against Mycobacterium Tuberculosis

Nanoparticles (NPs) that can activate macrophages infected with the tuberculosis causative pathogen Mycobacterium tuberculosis, could be an effective host directed therapy for the disease. In this study, curdlan was conjugated to poly(lactic-co-glycolic acid) (PLGA) to produce immunotherapeutic NPs. Various physicochemical characterizations were used to evaluate the curdlan-PLGA copolymer and the NPs. Molecular dynamics and simulation studies were used to characterize the interaction between curdlan, on the polymer and on NPs, with the Dectin-1 macrophage receptor. NPs with varying curdlan densities were evaluated for their effects on the production of pro- and anti-inflammatory cytokines in M. tuberculosis infected RAW264.7 macrophages. The killing efficacy of the NPs against intracellular M. tuberculosis was assessed. Physicochemical characterization of the curdlan-PLGA copolymer and NPs indicated successful formation of curdlan-PLGA copolymer and NPs of varying curdlan density (0-8% w/w) had sizes between 330 and 453 nm. Modelling studies showed curdlan to have a strong affinity for Dectin-1. Cytotoxicity assays showed the NPs to be non-toxic over 72 h. The proinflammatory cytokine TNF-α was found to be significantly upregulated by the NPs. The NPs reduced intracellular M. tuberculosis burden over 72 h. These NPs are a promising host directed therapy for intracellular eradication of M. tuberculosis.

Novel 3D ultrasound system for midline single-operator epidurals: a feasibility study on a porcine model

BACKGROUND

We developed a real-time 3D ultrasound thick slice rendering technique and innovative Epiguide needle-guide as an adjunct to single-operator midline epidural needle insertions. Study goals were to determine feasibility of the technique in a porcine model and compare the visibility of standard and echogenic needles.

METHODS

Thirty-four lumbar needle insertions were performed on six intact porcine spines ex vivo. Ultrasound scanning identified the insertion site and, using an Epiguide, the needle was guided into the epidural space through the ligamentum flavum in the midline plane, watched in real-time on the 3D ultrasound. Entry into the epidural space was judged by a loss-of-resistance technique. Needle visibility was rated by the anesthesiologist performing the technique using a 4-point scale; (0=cannot see, 1=poor, 2=satisfactory, 3=excellent), and later by an independent assessor viewing screenshots. The procedure was repeated at all lumbar levels using either the standard or echogenic needle.

RESULTS

Successful loss-of-resistance to fluid was achieved in 76% of needle insertions; needle visibility with echogenic needles (94.2% rated satisfactory/excellent) was significantly better than with standard needles (29.4% satisfactory/excellent, P<0.0001). Successful loss-of-resistance was 93% when mean needle visibility was rated as 'excellent'. Inter-observer agreement between assessors was 'near-perfect' (weighted kappa=0.83).

CONCLUSION

It is feasible to perform 3D ultrasound-guided real-time single-operator midline epidural insertions, in a porcine model. Echogenic needles were found to consistently improve needle visibility; and improved needle visibility tended to increase successful entry into epidural space.

Spectroscopic investigations on the binding of an iodinated chlorin p6-copper complex to human serum albumin

An iodinated chlorin p₆ copper complex showed high affinity to bind human serum albumin, the binding site was predicted and it was demonstrated that binding did not affect protein conformation.

A randomized controlled trial comparing Ametop™ with placebo for reducing pain associated with local anesthetic skin infiltration before neuraxial anesthesia in parturients

BACKGROUND

Between 10-22% of the general population experience needle phobia. Needle phobic parturients are at increased risk of adverse outcomes. We assessed the efficacy of topical Ametop™ (tetracaine 4%) gel in reducing the pain associated with local anesthetic skin infiltration before neuraxial block in non-laboring women.

METHODS

This was a prospective, randomized, double-blind, placebo-controlled study. Ametop™ or placebo was applied to the skin of the lower back at least 20min before neuraxial block using a standardized technique with 1% lidocaine skin infiltration. The primary outcome was numeric pain score (0-10) 30s after lidocaine infiltration. Groups were compared using Welch's t-test.

RESULTS

Thirty-six subjects in each group were analyzed. There was a statistically significant difference in the mean (standard deviation) pain score between the Ametop™ and the placebo groups: 2.36±1.80 and 3.51±2.22, respectively (P=0.019). There were no significant adverse events.

CONCLUSION

The mean numeric pain score in the Ametop™ group was 33% lower compared to the placebo group. Topical Ametop™ gel applied at least 20min before local anesthetic infiltration of the skin prior to neuraxial block in elective cesarean delivery may be a useful adjunct in needle phobic women.

Immunoprotective responses of T helper type 1 stimulatory protein-S-adenosyl-L-homocysteine hydrolase against experimental visceral leishmaniasis

It is well known that a patient in clinical remission of visceral leishmaniasis (VL) remains immune to reinfection, which provides a rationale for the feasibility of a vaccine against this deadly disease. In earlier studies, observation of significant cellular responses in treated Leishmania patients as well as in hamsters against leishmanial antigens from different fractions led to its further proteomic characterization, wherein S-adenosyl-L-homocysteine hydrolase (AdoHcy) was identified as a helper type 1 (Th1) stimulatory protein. The present study includes immunological characterization of this protein, its cellular responses [lymphoproliferation, nitric oxide (NO) production and cytokine responses] in treated Leishmania-infected hamsters and patients as well as prophylactic efficacy against Leishmania challenge in hamsters and the immune responses generated thereof. Significantly higher cellular responses were noticed against recombinant L. donovani S-adenosyl-L-homocysteine hydrolase (rLdAdoHcy) compared to soluble L. donovani antigen in treated samples. Moreover, stimulation of peripheral blood mononuclear cells with rLdAdoHcy up-regulated the levels of interferon (IFN)-γ, interleukin (IL)-12 and down-regulated IL-10. Furthermore, vaccination with rLdAdoHcy generated perceptible delayed-type hypersensitivity response and exerted considerably good prophylactic efficacy (∼70% inhibition) against L. donovani challenge. The efficacy was confirmed by the increased expression levels of inducible NO synthase and Th1-type cytokines, IFN-γ and IL-12 and down-regulation of IL-4, IL-10 and transforming growth factor (TGF)-β. The results indicate the potentiality of rLdAdoHcy protein as a suitable vaccine candidate against VL.

Immunostimulatory potential and proteome profiling of Leishmania donovani soluble exogenous antigens

Isolation of the soluble exogenous antigens (SEAgs), its immune response study and proteome profiling is an essential prerequisite for understanding the molecular pathogenesis of Leishmania donovani. The immunostimulatory potential of L. donovani SEAgs, purified from culture of L. donovani clinical isolate, was evaluated for their ability to induce cellular responses in treated/cured hamsters. SEAgs induced significant proliferative responses in lymphocytes (SI 5.6 ± 2.3; P < 0.01) isolated from cured hamster. In addition, significant NO production in response to SEAgs was also noticed in macrophages of hamsters, mouse and human cell lines (J774A-1 and THP1). Western blot analyses with antibodies against proteophosphoglycan (PPG; surface-expressed and secreted molecule) of L. donovani revealed that PPG molecules are also present in L. donovani SEAgs. Mass spectrometry (MS)-based proteome analysis of 12 protein bands of SEAgs through MALDI-TOF/TOF endorsed the identification of some Th1-stimulatory immunogenic proteins. These immunogenic proteins may offer increased hope for the discovery of new promising vaccine candidates against visceral leishmaniasis (VL). The overall results suggest that immunostimulatory molecules are present in the SEAgs, which may be further exploited, for developing a subunit vaccine against VL a fatal human disease.

Coating doxorubicin-loaded nanocapsules with alginate enhances therapeutic efficacy against Leishmania in hamsters by inducing Th1-type immune responses

BACKGROUND AND PURPOSE

The aim of the present study was to evaluate the immunomodulatory and chemotherapeutic potential of alginate-(SA) coated nanocapsule (NCs) loaded with doxorubicin (SA-NCs-DOX) against visceral leishmaniasis in comparison with nano-emulsions containing doxorubicin (NE-DOX).

EXPERIMENTAL APPROACH

NE-DOX was prepared using low-energy emulsification methods. Stepwise addition of protamine sulphate and SA in a layer-by-layer manner was used to form SA-NCs-DOX. SA-NCs-DOX, NE-DOX and Free DOX were compared for their cytotoxicity against Leishmania donovani-infected macrophages in vitro and generation of T-cell responses in infected hamsters in vivo.

KEY RESULTS

Size and ζ potential of the NE-DOX and SA-NCs-DOX formulations were 310 ± 2.1 nm and (-)32.6 ± 2.1 mV, 342 ± 4.1 nm and (-)29.3 ± 1.2 mV respectively. SA-NCs-DOX was better (1.5 times) taken up by J774A.1 macrophages compared with NE-DOX. SA-NCs -DOX showed greater efficacy than NE-DOX against intramacrophagic amastigotes. SA-NCs-DOX treatment exhibited enhanced apoptotic efficiency than NE-DOX and free DOX as evident by cell cycle analysis, decrease in mitochondrial membrane potential, ROS and NO production. T-cell responses, when assessed through lymphoproliferative responses, NO production along with enhanced levels of iNOS, TNF-α, IFN-γ and IL-12 were found to be up-regulated after SA-NCs-DOX, compared with responses to NE-DOX in vivo. Parasitic burden was decreased in Leishmania-infected hamsters treated with SA-NCs-DOX, compared with NE-DOX.

CONCLUSIONS AND IMPLICATIONS

Our results provide insights into the development of an alternative approach to improved management of leishmaniasis through a combination of chemotherapy with stimulation of the innate immune system.

Diffusion of chlorin-p6 across phosphatidyl choline liposome bilayer probed by second harmonic generation

We have investigated the diffusion of the photosensitizer Chlorin-p(6) (Cp(6)) across a egg lecithin lipid bilayer at different pH by the Second Harmonic Generation (SHG) method. Cp(6) has three ionizable carboxylic acid groups, and consequently, neutral and several ionic forms of Cp(6) are expected to be present in the pH range 3-8. The absorption spectra of Cp(6) get considerably modified in the presence of liposomes as the pH is decreased indicating that the drug liposome binding is pH dependent. The first pK(a) of interconversion (D-C) has been identified at pH ~7.0 by fluorescence measurement in an earlier work. In this work, the second pK(a) of interconversion (C-B) has been identified at pH ~4.8 by the hyper-Rayleigh scattering method. At acidic pH (3, 4, and 5), where species A, B, and C are dominant, the addition of liposomes to a Cp(6) solution generates an instantaneous rise (less than 1 s) in the second harmonic (SH) signal followed by decays whose time constants ranged from ten to hundreds of seconds. The instantaneous rise is attributed to the adsorption of Cp(6) to the outer lipid bilayer, and the decay is attributed to the diffusion of the neutral and charged (A and B) species of the drug. The observed fast and slow time constants for diffusion in the pH range 3-5 are attributed to the neutral (A) and ionic form (B) of Cp(6), respectively. At pH 6, the intensity of the generated SH signals on the addition of liposome reduced, and at physiological pH, it was too weak to be detected. These results are consistent with previous studies that show that the interaction between Cp(6) and egg-PC liposomes is pH dependent. At lower pH due to the presence of the hydrophobic species (A and B) of Cp(6), its interaction with liposomes is strong, and at higher pH, the abundance of the negatively charged hydrophilic species (C and D) decreases the interaction with the like charged liposomes. We have also studied the effect of increasing the bilayer rigidity by decreasing the temperature of the medium or by incorporating 50 mol % cholesterol in the lipid bilayer and observed that lowering of temperature has more profound effect on the diffusion rates. The characteristics of the SH signal changed significantly when liposomes incorporating 50 mol % cholesterol were used at a low (3 °C) temperature. Under these conditions, the SH signal consisted of an instantaneous (<1s) followed by a slower rise (10-90s), and then, it decayed on a much longer time scale. This slow rise of the SH signal at pH 3 and 4 may be attributed to the temperature dependent adsorption of the anionic species (B) of Cp(6) with the liposomes. Further investigations are required in order to understand clearly the pH dependent diffusion of this drug across lipid bilayers.

Development and performance evaluation of amphotericin B transfersomes against resistant and sensitive clinical isolates of visceral leishmaniasis

The present study was aimed to assess the efficacy of developed transfersome (TF-3) formulation bearing amphotericin B (AmB) against sensitive and resistant clinical isolates of L donovani and compared with conventional liposomal formulation (F-2) and free AmB (F-1). The skin permeation of AmB from TF-3 was performed using Franz diffusion cell using rat skin which showed fickian diffusion across the skin. When tested against L. donovani (intramacrophagic amastigotes), it has been observed that TF was more effective than F-1 and F-2 formulation in sensitive and resistant clinical isolates. The data provides evidences that the TF formulation owing to its fluidized behaviour imparted by sodium deoxycholate, enables to penetrate well in the infected cells and thus provide enhanced activity. The permeation study also supports this data as the flux value of AmB through TF formulation was 1.5 fold higher compared to conventional liposomes suggesting improved penetration and better partitioning in skin layers. Implicit to this preliminary data it is evident that the AmB loaded TF formulation has potential as alternate chemotherapeutic approach to control of VL. Potential utilities of novel formulation as a transdermal delivery of AmB for leishmaniasis necessitates further elaborated investigations which is underway in our laboratory.

Lonar lake, India: an impact crater in basalt

Discovery of shock-metamorphosed material establishes the impact origin of Lonar Crater. Coarse breccia with shatter coning and microbreccia with moderately shocked fragments containing maskelynite were found in drill holes through the crater floor. Trenches on the rim yield strongly shocked fragments in which plagioclase has melted and vesiculated, and bombs and spherules of homogeneous rock melt. As the only known terrestrial impact crater in basalt, Lonar Crater provides unique opportunities for comparison with lunar craters. In particular, microbreccias and glass spherules from Lonar Crater have close analogs among the Apollo specimens.

Effect of helium-neon laser irradiation on hair follicle growth cycle of Swiss albino mice

We report the results of a study carried out to investigate the effect of helium-neon (He-Ne) laser (632.8 nm) irradiation on the hair follicle growth cycle of testosterone-treated and untreated mice. Both histology and optical coherence tomography (OCT) were used for the measurement of hair follicle length and the relative percentage of hair follicles in different growth phases. A positive correlation (R = 0.96) was observed for the lengths of hair follicles measured by both methods. Further, the ratios of the lengths of hair follicles in the anagen and catagen phases obtained by both methods were nearly the same. However, the length of the hair follicles measured by both methods differed by a factor of 1.6, with histology showing smaller lengths. He-Ne laser irradiation (at approximately 1 J/cm(2)) of the skin of both the control and the testosterone-treated mice was observed to lead to a significant increase (p < 0.05) in % anagen, indicating stimulation of hair growth. The study also demonstrates that OCT can be used to monitor the hair follicle growth cycle, and thus hair follicle disorders or treatment efficacy during alopecia.

Prophylactic efficacy of high-molecular-weight antigenic fractions of a recent clinical isolate of Leishmania donovani against visceral leishmaniasis

T-cell mediated immune responses are key determinants to the natural course of infection caused by intracellular parasites such as Leishmania. Thus, T-cell activating proteins of these microbes continue to generate active interest particularly in view of their possible role in the design and development of newer and more effective vaccines. We have recently reported the presence of T-cell immunostimulatory antigens with the high-molecular-weight (MW) fractions (134-64.2 kDa) of whole Leishmania donovani antigen (strain 2001), which stimulated variable amounts of IFN-gamma, IL-12 and IL-10 in exposed immune individuals. The present study was undertaken to further evaluate these high-MW antigenic fractions (MW range >100-60 kDa) for potential protective efficacy. The high-MW region of the parasite was resolved into five antigenic fractions (Prep A-E) using continuous elution gel electrophoresis. Prior to in vivo protection studies in hamsters, these fractions were used to evaluate in vitro cellular responses in eight Leishmania-exposed individuals and treated cured hamsters. The protective efficacy of prep (A + B), C, D and E in combination with BCG was evaluated in inbred hamsters using standard immunization protocol. Proliferative responses were seen in all eight of eight exposed individuals to prep D [median stimulation index (SI): 5.2 (range 3.9-7.1)] and E [median SI: 5.6 (range 4.4-8.2)], five of eight individuals to prep B and prep C and three of eight to prep A [median SI: 0.2 (range 0.1-7.2)]. The median proliferative responses to prep D and prep E were significantly higher than to fraction prep A; (P < 0.05) but not to prep B and prep C. However, prep A-E induced equivalent levels of IFN-gamma, IL-10 and IL-12 cytokines. Fractions D and E also exhibited marked parasite inhibition in spleen (52.5% and 73.7%) and liver (65% and 80.2%) as compared with prep (A + B) (23% in spleen and 24% in liver) and prep C (38% in spleen and 24% in liver). Prep D and prep E vaccinated animals showed higher in vitro stimulatory responses (mean SI: 6.6 and 8.8) and nitric oxide (NO) induction (mean NO levels: 6.4 and 10.7 mug/ml) against whole cell extract as compared with other groups. The protection also correlated with presence of suppressed Leishmania-specific IgG levels in prep D and prep E immunized hamsters. These studies indicate the presence of immunostimulatory and protective molecules in 60-80 kDa region of L. donovani, which may be further exploited for developing a subunit vaccine.

The design and evaluation of placebo material for crude herbals: Artemisia afra herb as a model

Herbal materials are known to present significant challenges with regard to designing credible placebos. This study intended to demonstrate the possibility of designing placebo material for crude herbals and used Artemisia afra, a popular traditional herbal medicine in South Africa, as a model. To produce the placebo, step-wise solvent extractions were conducted on the plant leaves and the process was monitored spectrophotometrically and using high performance liquid chromatography (HPLC) with diode array detection. The odour and taste between the placebo and A. afra was matched by inclusion of linalool and sodium saccharin, respectively. The muscle relaxant activity of the placebo was evaluated using an isolated guinea-pig tracheal muscle preparation. The UV absorbance of the extracts and the HPLC chromatograms, showed that most of the phytochemical constituents had been removed and the placebo closely resembled the A. afra leaves. The EC(50) of the placebo and the leaves were 4846.00 and 68.49 mg/mL, respectively, which showed that not only did the A. afra leaves possess muscle relaxant activity, but that the placebo did not possess any significant activity compared with the A. afra leaves (p value 0.0001). These results demonstrated that it is possible to design credible, pharmacologically inert placebo material for crude herbals.

Proteophosphoglycan is differentially expressed in sodium stibogluconate-sensitive and resistant Indian clinical isolates of Leishmania donovani

Leishmania produce several types of mucin-like glycoproteins called proteophosphoglycans (PPGs) some of which are secreted while others are found on the surface of promastigotes and amastigotes. These proteins are thought to be important in the transmission, invasion and subsequent intracellular survival of parasites. The structure and function of PPGs are species and stage-specific in the case of L. major and L. mexicana, but no such information has hitherto been available for L. donovani. This study presents, for the first time, an initial characterization (localization) of PPG in sodium stibogluconate (SSG)-resistant and sensitive clinical isolates of L. donovani from Bihar (India) by confocal microscopy, flow cytometry and Western blotting using antibodies to L. major PPG. Confocal microscopy analysis revealed that both promastigotes and amastigotes possess PPG on their cell membrane and flagellar pocket membrane but its expression was variable in different isolates. The quantitative analysis by FACS and Western blotting showed that the expression and intensity of PPG bands was higher in SSG-resistant isolates. This study suggests the possibilities of involvement of PPG in drug-resistant mechanisms and of using PPG abundance as a marker for identifying drug-resistant clinical isolates in Indian kala azar.

In vitro and in vivo leishmanicidal activity of Dysoxylum binectariferum and its fractions against Leishmania donovani

The leishmanicidal effect of crude ethanolic extract of stem bark of Dysoxylum binectariferum and its fractions has been investigated against Leishmania donovani, the causative agent of visceral leishmaniasis. Ethanolic extract was lethal to promastigotes as well as amastigote forms in macrophage system at the concentration of 100 microg/ml. Chloroform fraction significantly inhibited promastigote multiplication and was also active against amastigotes in infected J774A.1 macrophages at 100 microg/ml. Hexane fraction was moderately active and the other fractions were inactive against both the forms. When tested in vivo in hamsters, ethanolic extract was toxic at 500 mg/kg whereas exhibited marginal activity (67.7+/-5.3%) at 250 mg/kg x 5, p.o. on day 7 post treatment (p.t.) which increases slightly (69+/-4.7) by day 30 p.t. Chloroform and n-hexane fractions exhibited 64.3+/-4% and 47.8+/-4.6% parasite inhibition at the dose of 100 mg/kg x 5 p.o., respectively. The pure compound, rohitukine, obtained from chloroform fraction showed weaker in vitro activity and was ineffective in infected hamsters. The lead potential of this plant need further investigations.

The leadership characteristics of the preceptor in selected clinical practice settings in Botswana

A non-experimental, explorative, descriptive, quantitative study was undertaken. The purpose was to explore and describe the views of preceptors and preceptees regarding the fulfilment of the role of the preceptor in selected clinical nursing practice settings in the Botswana context. The study included 72 preceptors and 200 nursing students/preceptees who voluntary agreed voluntarily to participate in the study. A questionnaire was used to collect data, which was analyzed by using descriptive and inferential statistics. The findings of this study indicated that the preceptor lacked leadership characteristics in the accompaniment of the preceptee. These constraints included the lack of desirable characteristics such as intellectual, emotional, physical and other traits that are common to all good leaders. Recommendations were stated for improvements in selecting preceptors with certain leadership skills for the clinical practice settings. The limitations of this study were highlighted.

A supersonic molecular beam study of the reaction of tetrakis(dimethylamido)titanium with self-assembled alkyltrichlorosilane monolayers

The reaction of a transition metal coordination complex, Ti[N(CH(3))(2)](4), with self-assembled monolayers (SAMs) possessing-OH, -NH(2), and -CH(3) terminations has been examined using supersonic molecular beam techniques. The emphasis here is on how the reaction probability varies with incident kinetic energy (E(i)=0.4-2.07 eV) and angle of incidence (theta(i)=0 degrees -60 degrees ). The most reactive surface is the substrate underlying the SAMs-SiO(2) with a high density of -OH(a) (>5 x 10(14) cm(-2)), "chemical oxide." On chemical oxide, the dynamics of adsorption are well described by trapping, precursor-mediated adsorption, and the initial probability of adsorption depends only weakly on E(i) and theta(i). The dependence of the reaction probability on substrate temperature is well described by a model involving an intrinsic precursor state, where the barrier for dissociation is approximately 0.2-0.5 eV below the vacuum level. Reaction with the SAMs is more complicated. On the SAM with the unreactive, -CH(3), termination, reactivity decreases continuously with increasing E(i) while increasing with increasing theta(i). The data are best interpreted by a model where the Ti[N(CH(3))(2)](4) must first be trapped on the surface, followed by diffusion through the SAM and reaction at the SAMSiO(2) interface with residual -OH(a). This process is not activated by E(i) and most likely occurs in defective areas of the SAM. On the SAMs with reactive end groups, the situation is quite different. On both the-OH and -NH(2) SAMs, the reaction with the Ti[N(CH(3))(2)](4) as a function of E(i) passes through a minimum near E(i) approximately 1.0 eV. Two explanations for this intriguing finding are made-one involves the participation of a direct dissociation channel at sufficiently high E(i). A second explanation involves a new mechanism for trapping, which could be termed penetration facilitated trapping, where the Ti[N(CH(3))(2)](4) penetrates the near surface layers, a process that is activated as the molecules in the SAM must be displaced from their equilibrium positions.

Acyclic pyrazolo[3,4-d]pyrimidine nucleoside as potential leishmaniostatic agent

A new synthesis of 6-amino-1-hydroxyethoxymethyl-4 (5H)-oxopyrazolo[3, 4-d]pyrimidine (4) has been mentioned. Compound 4 exhibited inhibition of amastigotes of Leishmania donovani to the extent of 89 % at 30 microg/mL, whereas iso-guanine analogue 5 had the inhibition only to the extent of 52.8% at 100 microg/mL in vitro. In hamster model the maximum inhibitory response for compound 4 against amastigotes multiplication was observed to be 94% at 50 mg/kg single dose for 5 consecutive days.

Identification of Leishmania donovani antigens stimulating cellular immune responses in exposed immune individuals

Human visceral leishmaniasis (VL), also known as kala azar (KA) in India, is a systemic progressive disease caused by Leishmania donovani. In VL, Th1 responses correlate with recovery from and resistance to disease and resolution of infection results in lifelong immunity against the disease. However, recent data suggest an important role for interleukin (IL)-10 in maintaining the resistant state. We evaluated whole cell extract (WE) and 11 antigenic fractions [F1-F11, molecular weight (MW) range of 139-24.2 kDa] from L. donovani (2001 strain, a fresh field isolate from Bihar), for their ability to induce in vitro T cell proliferation and production of interferon (IFN)-gamma, interleukin (IL)-12, IL-10 and IL-4 by peripheral blood mononuclear cells (PBMCs) of exposed immune individuals (14 patients with history of VL, 10 household endemic contacts) and 20 non-endemic healthy controls. Twenty-one of 24 exposed individuals and no healthy controls showed proliferative response to WE. Whole-extract activated IFN-gamma, IL-12, IL-10 levels were higher in the exposed group than in controls; IL-4 was not detectable in any of the samples. Among 21 responders to WE, frequent proliferative responses were seen to fractions F1-F4 (MW > 64.2 kDa) and none to fractions F5-F11; fractions F1-F11 stimulated comparable levels of IFN-gamma and IL-12 while IL-10 levels were higher in response to F5-F11 compared to F1-F4. These data demonstrate the presence of immunostimulatory antigens in the high MW fractions of whole L. donovani antigen. However, these fractions do not stimulate a Th1 response and produce variable amounts of IFN-gamma and the regulatory cytokine, IL-10. Hence, these high MW immunostimulatory fractions need to be evaluated in greater depth for their possible role as protective antigens.

Immunostimulatory cellular responses of cured Leishmania-infected patients and hamsters against the integral membrane proteins and non-membranous soluble proteins of a recent clinical isolate of Leishmania donovani

Development of an effective immunoprophylactic agent for visceral leishmaniasis (VL) has become imperative due to the increasing number of cases of drug resistance and relapse. Live and killed whole parasites as well as fractionated and recombinant preparations have been evaluated for vaccine potential. However, a successful vaccine against the disease has been elusive. Because protective immunity in human and experimental leishmaniasis is predominantly of the Th1 type, immunogens with Th1 stimulatory potential would make good vaccine candidates. In the present study, the integral membrane proteins (IMPs) and non-membranous soluble proteins (NSPs), purified from promastigotes of a recent field isolate, Leishmania donovani stain 2001, were evaluated for their ability to induce cellular responses in cured patients (n = 9), endemic controls (n = 5) of visceral leishmaniasis (VL) and treated hamsters (n = 10). IMPs and NSPs induced significant proliferative responses (SI 6.3 +/- 4.1 and 5.6 +/- 2.3, respectively; P < 0.01) and IFN-gamma production (356.3 +/- 213.4 and 294.29 +/- 107.6 pg/ml, respectively) in lymphocytes isolated from cured VL patients. Significant lymphoproliferative responses against IMPs and NSPs were also noticed in cured Leishmania animals (SI 7.2 +/- 4.7 & 6.4 +/- 4.1, respectively; P < 0.01). In addition, significant NO production in response both IMPs and NSPs was also noticed in macrophages of hamsters and different cell lines (J774A-1 and THP1). These results suggest that protective, immunostimulatory molecules are present in the IMP and NSP fractions, which may be exploited for development of a subunit vaccine for VL.

Immune responses in normal Indian langur monkeys (Presbytis entellus)--a primate model for visceral leishmaniasis

The Indian langur monkey (Presbytis entellus) is an experimental host for a range of human diseases and for the assessment of vaccine candidate antigens to some common parasitic infections. This experimental host is particularly suitable for the follow-up of immunological responses. To understand some of the mechanism that underlies the defense against experimental pathogens there is a need of the basic knowledge on antibody and cell mediated immune responses. In the present study 25 naïve monkeys were subjected to for assessment of their antibody responses to various human parasitic antigens as well as mitogen induced cellular responses. Only few monkeys were found to have low titer of antiparasitic antibodies. There was compressive dose dependent proliferative response of peripheral blood mononuclear cells. Unlike humans, the blastogenic as well as cytokine responses (IFN-gamma, IL-2 and IL-4) to Con A was considerably higher as compared to PHA. These findings are similar to what have been reported in other non-human primates, confirming the appropriateness of Indian langurs for pre-clinical trials.

Modulation of macrophage structure and function by low level He-Ne laser irradiation

Studies have shown that He-Ne laser irradiation can affect the biological functions of macrophages. The aim of the present study was to investigate the effect of He-Ne laser irradiation on the various functional parameters of macrophages and look for possible correlations in the effects to understand the mechanisms involved. Mice peritoneal macrophages were irradiated with a He-Ne laser (632.8 nm, approximately 10 W m(-2)) at energy densities ranging from 100 to 600 J m(-2) and the activities of lysozyme and cathepsin, phagocytosis, and cell spreading (markers of cell activation), as well as changes in NAD(P)H autofluorescence, were monitored. He-Ne laser irradiation was observed to lead to significant changes in all the parameters investigated. While lysozyme activity and spreading of the peripheral membrane were found to increase with the irradiation dose over the dose range investigated, the phagocytotic activity of macrophages, the activity of cathepsin, the observed decease in cell membrane fluidity and the observed increase in NAD(P)H level showed a peak at 200 J m(-2). Possible reasons for and the significance of the observed correlations are discussed.

Prophylactic potential of autoclaved Leishmania donovani with BCG against experimental visceral leishmaniasis

The prophylactic efficacy of autoclaved Leishmania donovani (ALD) and autoclaved L. major (ALM)--a heterologous vaccine developed against cutaneous leishmaniasis (used as a reference vaccine), along with BCG--was evaluated against L. donovani in hamsters (Mesocricetus auratus). Animals were immunized with triple doses (21 days apart) of either ALD or ALM (1.0 mg) with or without BCG (0.1 mg) and challenged 21 days later with 1 x 10(6) L. donovani amastigotes intracardially. Animals immunized with ALM + BCG and ALD + BCG yielded 94.3% and 86.1% parasite inhibition respectively in comparison to the BCG only and unvaccinated controls. Fifty and 33.3% of the vaccinated animals (ALM + BCG and ALD + BCG respectively) were completely devoid of parasites when tested on day 45 post-challenge (p.c.) and survived till the experiment was terminated. The mean survival of ALM + BCG and ALD + BCG groups (animals harbouring parasites) was longest (168 and 139 days respectively). No significant increase in anti-leishmanial antibody level (ELISA) was noticed in ALD + BCG and ALM + BCG groups whereas it increased progressively in the rest of the experimental groups. The lymphoproliferative responses to PHA and Con A, of the 2 vaccinated groups were comparable to that of normal controls on day 45 p.c. The study suggests that ALD along with BCG can offer substantial protection against visceral leishmaniasis in hamsters.

Establishment of asymptomatic Leishmania donovani infection in Indian langurs (Presbytis entellus) through intradermal route

Indian langurs, which were previously reported to be highly susceptible, were infected intradermally using variable numbers of promastigotes along with different doses, 1/2 pair, 5 pairs and 10 pairs respectively of salivary gland lysate (SGL). Although, all the monkeys developed mild infection and remained subclinically infected throughout the observation period, which later resolved, none of them could develop the classical disease. No marked antigen specific antibody or lymphoproliferative response was noticed throughout the experimental period. However, a late IFN-gamma response (by day 90 pi.) was demonstrated in monkeys infected with 2 x 10(6) promastigotes +10 pairs SGL. It seems that a single intradermal dose of promastigotes with or without SGLs had a vaccines like effect. Perhaps, multiple frequent inoculations, as happens in the natural situation, may be necessary for the development of full-blown disease.

Successful vaccination against Leishmania donovani infection in Indian langur using alum-precipitated autoclaved Leishmania major with BCG

Autoclaved Leishmania major (ALM) along with BCG, presently undergoing phase II clinical trial by WHO for its vaccine potential against cutaneous leishmaniasis, has been successfully evaluated in single and triple dose schedules against L. donovani in Indian langurs (Presbytis entellus). Encouraged with the results, another formulation alum-precipitated ALM (provided by WHO) along with BCG has been evaluated in this system. Eight monkeys were vaccinated with alum-precipitated ALM + BCG (1 mg of each per animal) while four were kept as unvaccinated controls. All were challenged with 100 x 10(6) amastigotes i.v. on day 60 post vaccination. Parasitic assessment in splenic tissue was performed on day 45, 90 and 180 p.c. Initially, seven of the eight vaccinated monkeys developed infection (two to six amastigotes per 1000 cell nuclei), which resolved by day 180 p.c., while the eighth monkey had a parasite burden of 14 amastigotes per 1000 cell nuclei on day 45 p.c. and died on day 130 p.c. On the other hand, there was progressive infection in unvaccinated control animals and three out of four died between days 110 and 120 p.c., and one monkey, which had low parasite burden, died on day 178 p.c. Prior to challenge, there was an initial rise in antileishmanaial antibodies in the vaccinated group compared to the unvaccinated control group, which later came down to normal level, while it remained higher in the unvaccinated control group. An increasing pattern of antigen-specific proliferative responses and interferon-gamma level to the two antigens--autoclaved L. donovani (ALD) and ALM--was observed in vaccinated monkeys throughout the experiment. There was a good correlation between parasite burden and IFN-gamma level on days 90 and 180 p.c., indicating IFN-gamma response as a sensitive parameter of immune status. The findings suggest alum-precipitated ALM+BCG as a potential vaccine against visceral leishmaniasis and warrants clinical trials.

He-Ne laser irradiation protects B-lymphoblasts from UVA-induced DNA damage

The effect of He-Ne laser (632.8 nm) pre-irradiation on UVA (343 nm)-induced DNA damage in the human B-lymphoblast cell line NC37 was investigated using the comet assay. He-Ne laser pre-irradiation was observed to result in a dose-dependent decrease in UVA-induced DNA damage. This effect was also found to be dependent on the incubation period between He-Ne laser pre-irradiation and the UVA exposure. Whereas the control cells with a higher DNA damage point to an initial ability of faster repair, both the control and the He-Ne laser pre-irradiated cells subsequently show the same rate of DNA repair. The results suggest that He-Ne laser irradiation protect the cells from UVA-induced DNA damage primarily through an influence on processes that prevent an initial DNA damage.

Elf-1 is a transcriptional regulator of the Tie2 gene during vascular development

Vascular development requires the tightly coordinated expression of several growth factors and their receptors. Among these are the Tie1 and Tie2 receptors, which are almost exclusively endothelial cell-specific. The critical transcriptional regulators of vascular-specific gene expression remain largely unknown. The Ets factors are a family of evolutionarily conserved transcription factors that regulate genes involved in cellular growth and differentiation. We have recently shown that the Ets factor NERF is a strong transactivator of the Tie1 and Tie2 genes. To extend these studies, we have begun to identify the Ets factors that are expressed in developing blood vessels of the chicken chorioallantoic membrane (CAM), a highly vascular embryonic network. RNA was extracted from microdissected CAM blood vessels, and reverse transcriptase-polymerase chain reaction was performed using oligonucleotides encoding conserved amino acids within the Ets domain. One of the polymerase chain reaction fragments was subcloned and identified as the chicken homologue of the Ets factor ELF-1, cELF-1. ELF-1 is most closely related to the Ets factor NERF. In situ hybridization and immunohistochemistry demonstrate that cELF-1 is enriched in developing chicken blood vessels. cELF-1 is also a strong transactivator of the Tie1 and Tie2 genes and can bind to conserved Ets sites within the promoters of these genes. A complex of similar size forms when gel shifts are performed with cellular extracts derived from the CAM blood vessels, which is recognized by an antibody against cELF-1. In summary, ELF-1 belongs to a subset of Ets factors that regulate vascular-specific gene expression during blood vessel development.

Helium-neon laser preirradiation induces protection against UVC radiation in wild-type E. coli strain K12AB1157

We have observed that preirradiation with a helium-neon laser (632.8 nm) induces protection against UVC radiation in wild-type E. coli strain K12AB1157. The magnitude of protection was found to depend on the helium-neon laser irradiance, exposure time, and period of incubation between helium-neon laser exposure and subsequent UVC irradiation. The optimum values for dose, irradiance and interval between the two exposures were found to be 7 kJ/m(2), 100 W/m(2) and 1 h, respectively. The possible involvement of singlet oxygen in the helium-neon laser-induced protection is also discussed.

PDEF, a novel prostate epithelium-specific ets transcription factor, interacts with the androgen receptor and activates prostate-specific antigen gene expression

Prostate cancer, the most frequent solid cancer in older men, is a leading cause of cancer deaths. Although proliferation and differentiation of normal prostate epithelia and the initial growth of prostate cancer cells are androgen-dependent, prostate cancers ultimately become androgen-independent and refractory to hormone therapy. The prostate-specific antigen (PSA) gene has been widely used as a diagnostic indicator for androgen-dependent and -independent prostate cancer. Androgen-induced and prostate epithelium-specific PSA expression is regulated by a proximal promoter and an upstream enhancer via several androgen receptor binding sites. However, little progress has been made in identifying androgen-independent regulatory elements involved in PSA gene regulation. We report the isolation of a novel, prostate epithelium-specific Ets transcription factor, PDEF (prostate-derived Ets factor), that among the Ets family uniquely prefers binding to a GGAT rather than a GGAA core. PDEF acts as an androgen-independent transcriptional activator of the PSA promoter. PDEF also directly interacts with the DNA binding domain of androgen receptor and enhances androgen-mediated activation of the PSA promoter. Our results, as well as the critical roles of other Ets factors in cellular differentiation and tumorigenesis, strongly suggest that PDEF is an important regulator of prostate gland and/or prostate cancer development.

Characterization of ESE-2, a novel ESE-1-related Ets transcription factor that is restricted to glandular epithelium and differentiated keratinocytes

Epithelial cell differentiation is tightly controlled by distinct sets of transcription factors that regulate the expression of stage-specific genes. We recently isolated the first epithelium-specific Ets transcription factor (ESE-1). Here we describe the characterization of ESE-2, a second epithelium-restricted ESE-1-related Ets factor. Like ESE-1, ESE-2 is induced during keratinocyte differentiation. However, whereas ESE-1 is expressed in the majority of epithelial cell types, ESE-2 expression is restricted to differentiated keratinocytes and glandular epithelium such as salivary gland, prostate, mammary gland, and kidney. In contrast to ESE-1, full-length ESE-2 binds poorly to DNA due to the presence of a negative regulatory domain at the amino terminus. Furthermore, although ESE-1 and the amino-terminally deleted ESE-2 bind with similar affinity to the canonical E74 Ets site, ESE-2 and ESE-1 differ strikingly in their relative affinity toward binding sites in the c-MET and PSMA promoters. Similarly, ESE-1 and ESE-2 drastically differ in their ability to transactivate epithelium-specific promoters. Thus, ESE-2, but not ESE-1, transactivates the parotid gland-specific PSP promoter and the prostate-specific PSA promoter. In contrast, ESE-1 transactivates the keratinocyte-specific SPRR2A promoter Ets site and the prostate-specific PSMA promoter significantly better than ESE-2. Our results demonstrate the existence of a unique class of related epithelium-specific Ets factors with distinct functions in epithelial cell gene regulation.

Role of the Ets transcription factors in the regulation of the vascular-specific Tie2 gene

The Tie2 gene encodes a vascular endothelium-specific receptor tyrosine kinase that is required for normal vascular development and is also upregulated during angiogenesis. The regulatory regions of the Tie2 gene that are required for endothelium-specific gene expression in vivo have been identified. However, the transcription factors required for Tie2 gene expression remain largely unknown. We have identified highly conserved binding sites for Ets transcription factors in the Tie2 promoter. Mutations in 2 particular binding sites lead to a 50% reduction in the endothelium-specific activity of the promoter. We have compared the ability of several members of the Ets family to transactivate the Tie2 promoter. Our results demonstrate that 1 of 3 distinct isoforms of the novel Ets transcription factor NERF, NERF2, is expressed in endothelial cells and can strongly transactivate the regulatory regions of the Tie2 gene in comparison to other Ets factors, which have little or no effect. NERF2 can bind to the Tie2 promoter Ets sites in electrophoretic mobility shift assays. These studies support a role for Ets factors in the regulation of vascular-specific gene expression and suggest that the novel Ets factor NERF2 may be a critical transcription factor in specifying the expression of the Tie2 gene in vascular endothelial cells.

Leishmania donovani: cellular and humoral immune responses in Indian langur monkeys, Presbytis entellus

We have previously reported that disease mimicking human visceral leishmaniasis can be established in Presbytis entellus, the Indian langur monkey, following a single intravenous challenge of 10(8) Leishmania donovani amastigotes. In the present report, infection was assessed in monkeys infected intravenously with a single dose of 10(8) amastigotes (HDA group), three weekly doses of 10(7) amastigotes (LDA group) and three weekly doses of 5 x 10(7) promastigotes (HDP group). Typical clinical infection was established in all three groups with significant parasite load. There was a gradual and sustained rise in anti-leishmania specific immunoglobulin G response, and a severe fall in the lymphoproliferative response to the T cell mitogens PHA and Con A by day 80 post infection (p.i.). The antibody level remained elevated until death in monkeys of the HDA and HDP groups; the T-cell responses showed a recovery prior to death. T-cell responses to leishmania antigen, however, could not be demonstrated in any of these monkeys prior to death. One monkey of the LDA group survived for 155 days and two monkeys spontaneously eradicated the infection. Surprisingly, one monkey of the HDA group also achieved spontaneous cure. In the three monkeys which eradicated infection spontaneously, the antibody level declined to baseline levels on day 180 p.i. with a well demonstrable antigen specific lymphoproliferative response; no parasites could be demonstrated in splenic aspirates by direct examination of culture. These data demonstrate that disease severity may be the function of the total inoculum dose rather than the stage of the parasite and that the immunological responses in the Indian langur model parallel the reported changes in human visceral leishmaniasis. This makes the langur a potentially useful model for the evaluation of candidate anti-leishmanial drugs and vaccines.

Identification by microscopically controlled comet assay of peritoneal macrophages in a mixture of peritoneal exudate for DNA strand break analysis

A simple modification of the alkaline comet assay allows the study of DNA damage in a specific cell type in a mixture of primary cells. Peritoneal macrophages from mice are selected from other peritoneal exudate cells without complex preparation and separation steps by their size and shape of the nuclei and their comets. The DNA damage can be well characterised by the manually monitored parameter 'tail length'. Complex measurement of the 'tail moment', often used for characterising DNA damage is not required, a fact which further simplifies the protocol. The distribution of tail length within one sample is symmetric and can be described by a Gaussian distribution and the mean tail length. As a first application, UV-A sensitivity of resident and stimulated macrophages was studied. The resident macrophages were more sensitive to UV-A than the stimulated ones. DNA damage repair follows the same simple monoexponential time course for both cell types. The simplicity of results, i.e., applicability of tail lengths and Gaussian statistics as well as monoexponential kinetics, suggest that microscopically controlled comet assay is well suited to study elementary processes of DNA damage induction and repair.

Role of ets factors in the activity and endothelial cell specificity of the mouse Tie gene promoter

The Tie gene encodes an endothelial cell receptor tyrosine kinase necessary for normal vascular development. The Tie gene promoter targets expression of heterologous genes specifically to endothelial cells in transgenic mice. Here we have characterized the promoter sequences critical for endothelial cell-specific activity in cultured cells and transgenic mice. Progressive deletions and site-directed mutations of the promoter showed that the critical endothelial cell-specific elements are an octamer transcription factor binding site and several Ets binding sites located in two clusters within 300 bp upstream of the major transcription initiation site. Among members of the Ets transcription factor family tested, NERF-2 (a novel transcription factor related to the ets factor ELF-1), which is expressed in endothelial cells, and ETS2 showed the strongest transactivation of the Tie promoter; ETS1 gave lower levels of stimulation and the other Ets factors gave little or no transactivation. Furthermore, the Tie promoter directed the production of high amounts of human growth hormone into the circulation of transgenic mice. The secreted amounts correlated with transgene copy number, being relatively insensitive to the effects of the transgene integration site. These properties suggest that Tie promoter activity is controlled by endothelial cell Ets factors and that it has potential for use in vectors for endothelial cell-specific gene expression.

The novel combination of fat clearance and immunohistochemistry improves prediction of the outcome of patients with colorectal carcinomas: a preliminary study

To evaluate the significance of micrometastases in relation to survival rate, specimens from 48 colorectal carcinoma patients were analysed after fat clearance. The number and size of the lymph nodes harbouring metastases and the significance of micrometastases for patients' survival were assessed. We found that although the majority of metastatic lymph nodes (71.8%) were 5 mm or less in diameter, their size had no effect on survival. Immunohistochemical staining of lymph nodes revealed that 15 of 25 patients with Dukes' stage B diagnosed by routine staining had micrometastases, 86% of these lymph nodes being less than 5 mm in diameter. The survival rate of this subgroup was found to be considerably poorer than that of Dukes' stage B patients with no micrometastases. None of the three patients with Dukes' stage A carcinoma had micrometastases. Since most of the metastases and micrometastases occur in lymph nodes of 5 mm and less and can be easily missed by routine examination, we suggest that fat clearance and routine immunohistochemical analysis of Dukes' stage B improve the prediction of outcome of colorectal cancer patients.

Serum tocopherols and lipids in patients with coronary artery disease

Serum tocopherols and lipids levels in 40 coronary artery disease patients were statistically analysed in relation to those of the normal controls and an attempt was made to define the correlation between tocopherols and various lipids. Serum tocopherols levels were found to be significantly low in coronary artery disease patients as compared to those of the controls implicating an inverse relationship between coronary artery disease and serum level of tocopherols. Coronary artery disease population did not register any significant change in various blood lipids, except triglyceride fraction, as compared to that of the normal population. Serum tocopherols and lipids were also analysed in relation to age and sex. The preliminary data suggest that coronary artery disease patients have sub-optimal tocopherols level (0.58 +/- 0.26 mg/dl) as compared to that of the normal controls (0.81 +/- 0.34 mg/dl; p < 0.001), which may be an important risk and/or contributing factor for atherogenesis and coronary artery disease

Vaccination of langur monkeys (Presbytis entellus) against Leishmania donovani with autoclaved L. major plus BCG

The protective potential of killed Leishmania major (ALM) along with BCG was evaluated against L. donovani in Indian langur monkeys in single and triple dose schedules. A delayed protection was observed in monkeys after a single dose schedule of ALM (3 mg)+BCG (3 mg) given intradermally 2 months before intravenous challenge with L. donovani. Triple dose schedule each of 1 mg ALM + 1 mg BCG was more effective. The status remained unchanged until the end of the experiment (approximately 8 months). The study indicates that a combination of ALM + BCG may be a good candidate vaccine for exploiting against human Kala-azar.

Funeral directors, mortuaries and necropsies: implications for necropsy consent rates and the prevention of infection

AIM

To evaluate the attitudes and experiences of funeral directors in relation to necropsies.

METHODS

All 1631 members of the National Association of Funeral Directors were surveyed by postal questionnaire about the purposes of necropsies, the technical and administrative problems associated with necropsied cases and their relations with relatives, mortuaries and pathology departments.

RESULTS

In total, 123 funeral directors completed the questionnaire (8% response rate). Workload, proportion of cases necropsied and type of mortuary did not influence answers. Necropsies were considered important for the assessment of treatment outcome, identification of inherited disease and junior pathologist training, but not for medical audit. There was strong support for more education about necropsies. The areas of necropsy practice most frequently discussed with relatives related to concerns about funeral delay and the involvement of the coroner or equivalent authority. Funeral directors occasionally counselled relatives for or against giving necropsy consent. The commonest technical problems associated with necropsies were difficulties in embalming, leakage of body fluids and scalpel penetration in visible areas. Few administrative problems were reported; the commonest was inflexibility in body collection times. There was strong support for a national code of practice to cover relations between funeral directors and mortuaries despite general satisfaction with relations with local pathology departments.

CONCLUSIONS

Although the relation among the funeral profession, mortuaries and pathology departments is largely satisfactory, a national code of practice for funeral directors and mortuaries is desirable.

Expression of myosin heavy chain transcripts in normal and cardiac mutant Mexican axolotls

In this study, we have cloned a 1.0 kb myosin heavy chain (MHC) cDNA by screening an axolotl heart cDNA library with the monoclonal antibody MF20 against a light meromyosin (LMM) region of MHC. The nucleotide sequence analysis shows 85-86% homology at the amino acid and 78-81% homology at the nucleic acid level with MHC from other vertebrates. Phylogenetic analyses suggest that axolotl beta-MHC forms a cluster with the myosin II group of vertebrate striated muscles. Within the myosin II cluster, axolotl beta-MHC forms a distinct subclade from avian MHC and is instead closer to mammalian MHC. RT-PCR analyses show that transcripts of beta-MHC are present at stage 2 and the onset of the MHC gene expression is at stage 8-10 (gastrulation). Expression increases with embryonic development and reaches a maximum at stage 20. Beyond stage 35, the heart-beat initiation stage, the expression level of beta-MHC is higher in cardiac muscle than in skeletal muscle. We could not detect significant differences in the levels of expression of MHC transcripts in normal and cardiac lethal mutant (c/c) axolotls (Ambystoma mexicanum).