New pentamidine analogues in medicinal chemistry.

Sixty years after its introduction, 1,5-bis(4-amidinophenoxy)pentane (Pentamidine) is still one of the most used drugs for the treatment of the first stage of Human African trypanosomiasis and other neglected diseases such as malaria and leishmaniasis. These protozoan infections are prevalent in the poorest world areas such as sub-saharian and developing countries, however the increasing immigration from these countries to the richest part of the world and the overlap of HIV with parasitic infections result in a growing number of cases in developed nations. A great effort has been made to develop new generations of diamidines for the treatment of these infections transmitted by insects. This review summarises the synthesis and evaluation of pentamidine analogues reported in the last years in the effort to find new drugs with better pharmaceutical activity, higher lipophilicity and lower citotoxycicty.

Lymphangioma communicating with the excretory system.

Lymphangioma is a rare benign tumor caused by failure in the development of the lymphatic communicating system. The corresponding nomenclature is confusing. In recent years ''renal lymphangiectasia'' is the preferred name. Although this disease may occur in any site of the body, the neck (75%) and axillary area (20%) are the most common sites, and the kidney is occasionally involved. We report a case of lymphangioma communicating with the urinary system in a 61-year-old man diagnosed by CT scan treated with nephrectomy and histological confirmation.

Intravitreal bevacizumab therapy for choroidal neovascularization secondary to age-related macular degeneration: 6-month results of an open-label uncontrolled clinical study.

PURPOSE: To investigate the 6-month safety and clinical outcomes of intravitreal injections of bevacizumab administered to treat choroidal neovascularization secondary to age-related macular degeneration. METHODS: Twenty-seven patients underwent 1.25 mg intravitreal injections of bevacizumab at baseline. A similar intravitreal injection was administered to all eyes at 1 and 2 month follow-up visits. At baseline and at each follow-up visit (1, 2, 3, and 6 months), patients underwent best-corrected visual acuity (BCVA) measurement, fluorescein angiography, indocyanine green angiography, and optical coherence tomography. Laboratory testing, visual field analyses, and endothelial cell counts were performed at baseline and third and sixth months. RESULTS: At 3 months, the mean BCVA remained substantially stable at 20/100. Mean central retinal thickness (CRT) decreased from 373 to 279 microm (p<0.01). Mean lesion greatest linear dimension (GLD) decreased from 4087 to 3782 microns (p<0.01). At 6 months, mean BCVA slightly decreased from 20/100(-1) to 20/125(-3) (not significant, p=0.40). Mean CRT was still inferior to baseline (305 microm, p<0.01). Mean lesion GLD was 4186 microm, not different from baseline values (p=0.59), but superior to 3-month mean GLD (p<0.01). Significant visual field defects or endothelial cell losses were not detected at 3 and 6 months. Laboratory testing did not reveal any clinically significant deviations compared to baseline values. CONCLUSIONS: Intravitreal therapy using bevacizumab over 6 months showed stabilization of visual acuity and choroidal neovascularization activity; the safety data were convincing.

Inguino-scrotal hernia of a double district ureter: case report and literature review.

Ureteral hernia is uncommon and usually misdiagnosed. From an anatomic point of view, we can distinguish between two uretero-inguinal hernias: intraperitoneal and extraperitoneal. Ureter inguinal hernias are nearly always indirect. This kind of hernia can include the ureter alone or, frequently, other abdominal sliding organs within the hernia sac (bladder, bowel tracts, etc.). Kidneys and urinary tracts present normal anatomic conformation, although renal ptosis may be found. As of July 2004, 139 cases of ureteral hernia had been described in the literature. Here we report a case of inguino-scrotal herniation of double district ureter and review the current literature to analyze the main clinical characteristics of this pathology and to establish pitfalls.

A 24-month survey on root canal treatment performed by NiTi engine driven files and warm gutta-percha filling associated system.

AIM: Techniques based on NiTi engine driven files for shaping and warm gutta percha for obturing the root canal space are becoming more and more popular. Aim of this paper is to evaluate, by a clinical longitudinal study, the type of sealing and the outcome of endodontic treatment, performed by new Profile and Thermafil technique, in teeth with or without periapical lesions. METHODS: A total of 122 teeth in 64 patients were consecutively enrolled in the study; 63 teeth had normal periapical status (Group A) and 59 teeth had periapical lesion (Group B). Endodontic therapy was carried out by Profile .04 and Profile .06 NiTi engine driven files and the obturation was made by Thermafil, a filling technique based on heated gutta-percha surrounding a plastic carrier. The type of sealing was evaluated by a score (A best - D worst) and the type of healing was classified as complete, incomplete and failure according to previous published data. The radiographical outcome of the teeth was evaluated by independent observers after 24 months. Data were analysed by non parametric statistics. RESULTS: At the end of the study, 115 teeth (59 group A and 56 group B) were examined. The quality of sealing was evaluated and some differences were reported comparing different types of teeth. The radiographic outcome was evaluated and 94.9% showed to be completely healed in group A and 48.2% in group B (p=0.0001). CONCLUSION: The technique based on NiTi engine driven files and Thermafil heated gutta-percha has shown, after 24 months, results which were comparable to other root canal shaping and filling methods.

Experimental evidence of "vibrational resonance" in an optical system.

The experimental evidence and characterization of "vibrational resonance" in a bistable vertical cavity laser are reported. The system is driven by two periodic forcings, with frequencies differing by several orders and studied in the case of both symmetrical and asymmetrical quasipotentials. The phenomenon shows up in the dynamics of the polarized laser emission as a resonance in the low-frequency response and signal-to-noise ratio, depending on the amplitude of an applied high-frequency modulation. The possibility to use the phenomenon for low-level detection is experimentally demonstrated.

Adaptation of SUBSTOR for controlled-environment potato production with elevated carbon dioxide.

The SUBSTOR crop growth model was adapted for controlled-environment hydroponic production of potato (Solanum tuberosum L. cv. Norland) under elevated atmospheric carbon dioxide concentration. Adaptations included adjustment of input files to account for cultural differences between the field and controlled environments, calibration of genetic coefficients, and adjustment of crop parameters including radiation use efficiency. Source code modifications were also performed to account for the absorption of light reflected from the surface below the crop canopy, an increased leaf senescence rate, a carbon (mass) balance to the model, and to modify the response of crop growth rate to elevated atmospheric carbon dioxide concentration. Adaptations were primarily based on growth and phenological data obtained from growth chamber experiments at Rutgers University (New Brunswick, N.J.) and from the modeling literature. Modified-SUBSTOR predictions were compared with data from Kennedy Space Center's Biomass Production Chamber for verification. Results show that, with further development, modified-SUBSTOR will be a useful tool for analysis and optimization of potato growth in controlled environments.

A very mild and chemoselective oxidation of alcohols to carbonyl compounds.

Efficient oxidation of primary alcohols and beta-amino alcohols to the corresponding aldehydes and alpha-amino aldehydes can be carried out at room temperature and in methylene chloride, using trichloroisocyanuric acid in the presence of catalytic TEMPO: aliphatic, benzylic, and allylic alcohols, and beta-amino alcohols are rapidly oxidized without no overoxidation to carboxylic acids. Secondary carbinols are slowly oxidized so that the reaction is highly chemoselective. Reaction: see text.

A simple preparation of ketones. N-protected alpha-amino ketones from alpha-amino acids.

[reaction: see text] Carboxylic acids and amino acids are readily converted, under mild conditions, into the corresponding activated esters, which are reacted with Grignard/CuI reagent to give the corresponding ketones in nearly quantitative yields. The compounds were recovered substantially pure from the reaction mixtures.

Noise-assisted transmission of binary information: theory and experiment.

We study the response of a bistable vertical cavity surface emitting laser to an aperiodic binary signal, by adding a variable amount of noise. The resulting behavior is an example of aperiodic stochastic resonance, and in this work we give a detailed comparison between analytical and numerical results and accurate experimental measurements. We characterize the phenomenon by using different appropriate indicators, which also allow us to quantify the binary information transmission. We show that the quality of the transmission is enhanced by a suitable amount of noise, and we give a physical picture of the phenomenon.

A new supported reagent for the photochemical generation of radicals in solution.

A new polymer-supported radical source was developed by loading an N-hydroxy thiazole 2(3)-thione on a Wang resin. This new supported reagent can be employed for a solid-phase version of the Hunsdiecker reaction or to liberate free alkoxy radicals, in a variant of the "catch and release" technique, under very mild conditions (irradiation with a discharge lamp) and simplifying the purification procedure.

Experimental evidence of binary aperiodic stochastic resonance

A novel kind of aperiodic stochastic resonance is experimentally studied in a vertical cavity surface emitting laser. We characterize the response of the system to a random, binary signal as a function of an applied external noise. A maximum in the input-output correlation is found for a nonzero added noise. We present analytic results with a good agreement with the measurements. We also discuss the physical meaning of the phenomenon using simple arguments, and we compare it to stochastic resonance.

Experimental evidence of coherence resonance in an optical system

Experimental evidence of coherence resonance in an optical system is reported. We show that the regularity of the excitable pulses in the intensity of a laser diode with optical feedback increases when adding noise, up to an optimal value of the noise strength. Both phase and amplitude fluctuations of the pulses play a relevant role in the dynamics of the system. We introduce the joint entropy of the two variables to generalize the indicator of coherence, and we put in evidence the mechanism of destruction of the excitable orbit after the resonance.

Stochastic resonance in vertical cavity surface emitting lasers

We report a detailed experimental investigation of stochastic resonance (SR) in the polarized emission of a pump-modulated vertical cavity surface emitting laser. We characterize SR in the time and frequency domains, with a quantitative agreement with existing theories. We further report a statistical analysis of SR in terms of residence-time probability distributions exhibiting alternative features which are fully explained here. By using an accurate choice of the indicator, we are also able to give clear evidence of bona fide resonance.

Convective lyapunov exponents and propagation of correlations

We conjecture that in one-dimensional spatially extended systems the propagation velocity of correlations coincides with a zero of the convective Lyapunov spectrum. This conjecture is successfully tested in three different contexts: (i) a Hamiltonian system (a Fermi-Pasta-Ulam chain of oscillators); (ii) a general model for spatiotemporal chaos (the complex Ginzburg-Landau equation); (iii) experimental data taken from a CO2 laser with delayed feedback. In the last case, the convective Lyapunov exponent is determined directly from the experimental data.

Noise-assisted binary information transmission in vertical cavity surface emitting lasers.

The response of a polarization-bistable vertical cavity surface emitting laser to a small amplitude, pseudorandom binary signal is experimentally studied. A high-contrast output is obtained when the optimum amount of noise is added to the system. The quality of the transmission, measured by the bit-error rate, exhibits a resonantlike behavior as a function of the input noise. We analyze possible applications of this transmission scheme to optical communications and compare it with those used in a standard amplitude modulation scheme.

Mineral fibre sampling and size selection.

Potential health hazards due to fibre inhalation are only evaluated in a limited way by simple optical microscopy examination of the membrane filters on which the fibres have been collected. One must consider the amount of fibres deposited and persisting in the most vulnerable organ compartments. Exposure evaluated in this way must take account of the deposition efficiency and relative clearance efficiency of different regions of the respiratory tract, which depends mainly on the diameter and length distribution of the fibres. The fibre diameter roughly indicates the deposition site in the respiratory tract, while the length is mainly connected with toxicity. For these reasons, at international level, special samplers have been recently proposed, capable of distinguishing the fibre sizes, in order to separate the so-called 'thoracic fraction' (the total fibres which penetrate beyond the larynx) and the 'respirable fraction' (only the fibres reaching the non ciliated respiratory area), which represent the most interesting sizes as far as health effects are concerned. Our purpose in this context is to explore the feasibility of using the Inertial Spectrometer (INSPEC) as a sampler that separates the fibres according to their aerodynamic diameter. The optical and electron microscope observations of the samples demonstrate a satisfactory size separation of the fibres and alignment along the flow lines. Therefore, INSPEC is successful in restricting the microscopic analyses to the potentially noxious fibres and in assessing specific concentrations for each diameter interval.