A compact-rigid multi-analyser for energy and angle filtering of high-resolution X-ray experiments. Part 2. Efficiency of a single-crystal-comb.

Diffraction instruments using filtering by one or several analyser crystals exist since the 1980s and 1990s at synchrotron radiation sources, but, due to its low efficiency, this filtering is little used on laboratory sources. In order to overcome this limitation, the efficiency of a small diffraction filtering multi-analyzer block (MAD block) realized with a `single-crystal-comb' curved on a rigid support is demonstrated here. The geometry of this curved surface is logarithmic spiral and is optimized to allow multi-filtering over a relatively important diffraction angular range and to be also applicable over an X-ray spectral range. The efficiency of such a small rigid-compact MAD block consisting of this single-crystal-comb generating 20-50 Si(111) single-crystal blades, associated with a block of Soller collimators, is demonstrated. The angle between each crystal is 0.1°, so the measurement range of the comb is 2-5°. The geometry of this system has been optimized for operation with a synchrotron X-ray source over an energy range of 22 keV to 46 keV and could be used with laboratory X-ray sources (Ag Kα1, 22.1 keV). This MAD block complements and exploits the qualities of the `photon-counting' detectors which have very low intrinsic noise. Their joint efficacy is supported by powder pattern measurements of a LaB6 reference sample and of several heterogeneous samples of cultural heritage materials, carried out at 22 keV on the D2AM beamline at the ESRF. Their signal-to-noise ratio is excellent (1000/1) and allows the detection thresholds of the measurements (from 3-1% to 0.1%) to detect minor phases in the studies of `real' heterogeneous materials to be drastically improved.

Molecular structure of a D-homoandrostanyl steroid derivative: single crystal and powder diffraction analyses.

The knowledge of the structure of a molecular crystal is frequently a prerequisite for the understanding of its solid state properties. Even though single-crystal diffractometry is the method of choice when it comes to crystal structure determination, methods using powder diffraction data become more and more competitive. There has been much recent interest in the development of a new generation of "direct-space" approaches that are particularly suited for molecular crystals. The crystallographic structure of a steroid derivative molecule (17,17-di-n-propyl-17a-aza-D-homo-5alpha-androstan-3beta-ol) was obtained in two independent ways: from a single crystal by laboratory X-rays and from a polycrystalline powder by high-resolution synchrotron powder diffraction. The molecule crystallizes in the orthorhombic space group P2(1)2(1)2(1) (a = 6.5346, b = 17.6006 and c = 19.6978 A). Hydrogen bonds form infinite chains of molecules parallel to the c axis.

[Chemistry of cosmetics in antiquity]. / Chimie et maquillage dans l'Antiquité.

Several texts, statues and paintings denote the importance of make up and eye medicines since the earliest periods of Egyptian history. We have investigated cosmetic powders that were preserved in original alabaster and reed containers. Quantitative crystallographic and chemical analysis of the mineral and organic components revealed surprising facts. In addition to the well known galena PbS and cerussite PbCO3, two unexpected constituents have been identified: laurionite PbOHCl and phosgenite Pb2 (CO3) Cl2, which are rare halide minerals found in lead slag only in certain places where the sea water has weathered lead debris left over from silver mining operations in Antiquity. Alteration of natural lead minerals is also unlikely, given the excellent state of conservation of the reed vessels. This evidence indicates that laurionite and phosgenite were synthesised artificially. Support for this statement comes from recipes of medicinal products to be "used in ophthalmology" reported by Greco-Roman authors such as Dioscorides and Pline (1st Century B.C.): silver foam PbO is crushed and mixed with rock salt and sometimes with natron (Na2CO3). The reaction seems to be straightforward. However, our experiments in the laboratory have shown a major difficulty, arising from the concomitant production of alkali, which raises the pH and leads to different products. It follows that the Egyptians very early mastered this kind of chemical synthesis and technology, a fact of great importance in the History of Sciences. Fire-based technology had been mastered to manufacture Egyptian Blue pigments since the third millennium B.C. The present results now suggest that wet chemistry was already known 4000 years ago. This key finding provides a new insight into the chemical technology of far greater antiquity than has previously been believed. Yet, an important question remains relative to the ultimate motivation for these technological developments. If the Egyptians initially only aimed at different nuances of grey, they could use cerussite, an easily accessible mineral, crushed and mixed with galena. Thus, one should seek other motivations; we shall propose to consider a religious-ritual context, ultimately linked to a pharmaceutical aspect.

The effect of subinhibitory concentrations of some antibiotics on the hydrophobicity of gram-negative bacteria.

Cell surface hydrophobicity is currently regarded as an important factor in promoting bacterial adherence to a wide variety of surfaces. This feature was investigated in some Gram-negative bacteria isolated from urinary tract infections and the extent to which their surface characteristics were affected by subinhibitory concentrations of some antibiotics was assayed. Surface properties were evaluated using the salting-out technique (SAT) and bacterial absorption to n-hexadecane (BATH). SAT showed that all except 3 Escherichia coli strains were autoaggregating. BATH detected more hydrophobic characteristics in the stationary phase of bacterial growth. Pretreatment with antibiotics generally reduced hydrophobicity and thus affected the initial reversible phase of attachment of bacteria to eukaryotic cells.

[Mixed culture of Enterococcus faecium SF 68 with pathogenic intestinal bacterial strains]. / Colture miste diEenterococcus faecium SF 68 con ceppi batterici patogeni intestinali.

An antagonistic activity of Enterococcus faecium SF 68 towards Plesiomonas shigelloides, Aeromonas sp., enteropathogenic Escherichia coli and Yersinia enterocolitica has been studied and demonstrated.

[Evaluation of in vitro antibiotic sensitivity: critical features of the MIC]. / Valutazione della sensibilità "in vitro" agli antibiotici: aspetti critici della MCI.

Current methods for the "in vitro" study of antibiotic activity, as minimum inhibitory concentration, expose bacteria to constant concentrations of antibiotics. The "in vivo" situation is significantly different, since the antibiotic concentration changes with time. Pharmacokinetic models are "in vitro" experimental systems that seek to simulate conditions of exposure of bacteria to antimicrobial agents that exist in blood and tissues. All of these systems are complicated constructions. A new simple "in vitro" kinetic model, based on solid phase growth, is described.

[Urinary infections: observations on the frequency of microbial isolation at the hospital environment and its surroundings]. / Infezioni urinarie: osservazioni sulla frequenza di isolamenti microbici in ambiente ospedaliero e sul territorio.

Numerous studies have been carried out to specify bacterial frequencies in the urinary tract infections. In such researches the prevalence of Gram negative bacterial species has generally emerged, the most part of these ones would be Enterobatteriaceae (and among them E. coli has a special prominent position); on the other hand several Authors have often found, among other bacterial groups (Gram positive bacteria, Pseudomonas etc.) involved in such pathologies, some differences (also remarkable) in relation to various factors, among them, the hospitalizing condition, the clinical situation, the type of infection etc. In this research we have carried out a statistical analysis of the bacterial frequencies relative to 321 positive urine cultures, trying to point out their differences in relation to hospitalized or ambulatorial patients and to single are mixed infections; above all with regard to three bacterial groups: Enterobatteriaceae, Pseudomonas species and Gram positive bacteria. The most evident result has been the absolute prevalence of Enterobacteriaceae, among them the E. coli has represented, almost always, the most frequent isolated species, followed by Proteus mirabilis, in every kind of patient (hospitalized or ambulatorial) and infection, single or double (we didn't notice, in this research, infections supported by more than two species). Moreover, we noticed, but with less clearness, especially in relation to the numerical dimension of the observations and to the short comparison of the two kind of patients, some indications pointing out that hospitalized patients (in comparison with the ambulatorial) were charged with a major frequency of the two kind of patients, some indications pointing out that hospitalized patients (in comparison with the ambulatorial) were charged with a major frequency of infections supported by Gram + bacteria and Proteus mirabilis, while the Pseudomonas species presented an opposite behaviour (contrary to what several Authors generally report in literature: but a pollution problem of the specimen might have had some influence); and as regard the single infections we observed, among them, a greater frequency of the E. coli and Gram + bacteria than among the double infections, while the Pseudomonas species happened the contrary.

[Combining indirect hemagglutination with the direct agglutination as a parameter for evaluating patients sent for serological verification of toxoplasmosis]. / L'abbinamento dell'emoagglutinazione indiretta (IHA) con l'Agglutinazione diretta (AD) quale parametro valutativo di pazienti inviati per l'accertamento sierologico della toxoplasmosi.

The importance that Toxoplasma gondii congenital infection may assume is still representing a stimulus for trying to improve Toxoplasmosis serological diagnosis; task, this one, which Laboratory is charged with, and that is often hard, particularly when we have to value the possibility of an infection in progress. With the purpose to complete the results obtained in a preceding work of ours, we have valued two among the most commonly used tests for Toxoplasmosis serodiagnosis, the AD (direct agglutination provided by BioMerieux) and the IHA (indirect haemoagglutination provided by Behring), together and separately, in order to make use of their coupling with major security and effectiveness, on the ground of the results obtained on two different groups of individuals, in the number of 125 for each group; for these groups it was possible to expect a different index of receptivity and a different percentage of recent or in progress infections. It was come out, as regards the IHAm a very good degree of assurance in trying to single out the past immunity, while this test wouldn't generally seem to be able to offer sufficient indications to distinguish the recent or in progress infection from past immunity, as it often declares, in fact, middle-high titres also in cases probably referable to the last mentioned situation. The AD has offered a good tribute in estimating the past immunity and it would also appear to give assurance in singling out recent or in progress infection (thanks to the possibility to determine IgM presence); while the presumed capacity of this test in revealing cases of very early infection has resulted not sufficiently assured. In substance the coupling of the two test, which in the direct comparison have shown a good correlation, but also several discordances, seems to be an useful procedure of reciprocal confirmation as regards the singling out of immunity; while the possibility of showing the recent or in progress infection--anyway, always a difficult task, above all, when, as it happened in this research, we deal with it without being able to follow the titre evolution in the time-should be entrusted with major certainty to the AD.

[Aztreonam: monocenter microbiological study with prevention experience in surgery]. / Aztreonam: indagine microbiologica monocentrica con esperienza di profilassi in chirurgia.

Aztreonam is a monobactam antibiotic active against aerobic gram-negative bacteria. The susceptibility of 127 urinary tract isolates to aztreonam, cefotaxime, cefonicid and ceftazidime was determined. Aztreonam showed good antibacterial activity even against Pseudomonas spp. Only 7 bacterial strains were resistant to aztreonam. The clinical efficacy and pharmacokinetics of aztreonam were assessed in two patients treated for urinary tract infections. The concentrations of aztreonam in serum and urine are reported. Aztreonam safety was evaluated on 20 patients given aztreonam immediately prior to an elective abdominal, urinary or gynecological operation. The results provide support for the use of aztreonam for prophylaxis.

[Antibiotic resistance at a hospital environment. Observations from 1980 to 1986]. / Antibioticoresistenza in ambiente ospedaliero. Osservazioni dal 1980 al 1986.

A total of 1659 bacteria Strains were examined for susceptibility to different drugs by the Kirby-Bauer method. The isolates came from the General Medicine ward of Castellamonte's hospital (USSL 40). The results were retrospectively studied and statistically elaborated. The study lasted from 2 to 7 years depending on the antibiotic considered. The isolates included: Escherichia coli, Klebsiella spp., Serratia spp., Citrobacter spp., Proteus mirabilis, Proteus IND+, Pseudomonas aeruginosa, Pseudomonas spp., Staphylococcus aureus, Staphylococcus spp., Streptococcus faecalis. Penicillines, Cefalosporines, Aminoglycosides, Quinolones, Tetraciclines, Nitrofurantoin, Macrolides, Rifampins, Lincosides and peptide antibiotics were tested. The results of this study can be useful for the choice of the antibiotics in non-specific therapy of infectious diseases and show the frequency of isolation of resistant strains from hospitalized patients. Furthermore it would be important to constitute a regional-epidemiological centre of Infectious Diseases.

In vitro antimicrobial activity in comparison with tonsillar tissue penetration of mezlocillin.

The aim of this study was to determine the role of mezlocillin, a new acylureidopenicillin, in otorhinolaryngology. One hundred and forty-four bacterial strains were isolated from 100 patients suffering from infections of the oropharyngeal tract. Among the isolates only 10 (6.9%) resulted in being mezlocillin-resistant by the agar diffusion method. Minimum inhibitory and minimum bactericidal concentrations were also determined. Pharmacokinetic parameters e.g., diffusion in tonsillar tissue and serum concentrations, were studied. Mean mezlocillin tonsillar levels of 3.5 micrograms/g and 1.8 micrograms/g and serum concentrations of 60.2 micrograms/ml and 10.6 micrograms/ml, 1 h and 4 h respectively after administration, were found.

[Novel characteristic of the genus Campylobacter: Campylobacter-like organisms]. / Nuove caratteristiche del genere Campylobacter: I "Campylobacter like organisms".

The first report of human infections due to Campylobacter dates back to 1947. These microorganisms, classified initially as Vibrio, had been known for many years as agents of several diseases in animals. In 1963 they were grouped in the new Genus Campylobacter belonging to Spirillaceae. Campylobacter are ever more important, particularly C. jejuni, which is an ubiquitous agent of diarrhoea in children. Other microorganisms of this Genus, the "gastric Campylobacter-like organisms" type I, otherwise known as Campylobacter pyloridis, are responsible for gastric diseases.

Adherence of Trichomonas vaginalis to cell culture monolayers.

The in vitro adherence to WISH cells of a pathogenic Trichomonas vaginalis strain was studied with a method utilizing thymidine-labeled protozoa. A marked dose-related adherence was observed. Glutaraldehyde fixed trichomonads were not adherent. The presence of fetal calf serum during the assay did not influence attachment. Concanavalin A inhibited adherence of protozoa. Complete or partial inhibition of adherence was achieved by preincubating WISH cells with Lactobacillus fermentum or Streptococcus agalactiae. Finally, pretreatment of cells with alpha-estradiol, beta-estradiol, progesterone and estrone influenced attachment of protozoa, whereas estriol was ineffective. These results suggest that adherence of Trichomonas vaginalis is dependent on different factors, whose manipulation may have clinical relevance in preventing recurrence of trichomonad vaginitis.

Effect of prolonged administration of low doses of dietary retinoids on cell-mediated immunity and the growth of transplantable tumors in mice.

A study was conducted on the activity exerted by prolonged dietary supplementation with progressive amounts of retinoids on cell-mediated immune responses and the growth of transplantable tumors in mice. A few groups of BALB/c mice received 0 (group C), 50 (group A 50), 200 (group A 200), 500 (group A 500), and 1,000 (group A 1000) IU retinol palmitate/mouse/day in drinking water for 150 days. At progressive intervals mice from each group were tested for proliferative responses to concanavalin A (Con A), Escherichia coli lipopolysaccharide, interleukin-2, and interferon-gamma release to Con A. Ten mice from each group were also challenged with the 90-100% tumor-inducing dose of 3 distinct transplantable tumors. At the end of the experiment the principal organs were histologically examined, and the accumulation of vitamin A was evaluated. In groups A 200, A 500, and A 1000, an increase in the proliferative responses and production of lymphokines as compared to those in group C occurred after 60-90 days, but vanished after 150 days. The takes of the 3 tumors were impaired when the challenges were performed on days 75 and 150. This enhancement of distinct functions of cellular reactivity and resistance to transplantable tumors showed a linear relationship with the amount of supplemental retinol palmitate for the first 60-90 days. After 150 days, however, these enhancement effects vanished or tended to decrease.

Bactericidal effects induced by laser irradiation and haematoporphyrin against gram-positive and gram-negative microorganisms.

Laser irradiation of tissues treated in vivo with haematoporphyrin (Hpr) is known to result in a cytocidal effect, reportedly more pronounced in tumour tissues. To ascertain whether this cytocidal phenomenon can occur not only in eukaryotic but also in prokaryotic cells, the authors devised a model system in vitro consisting of bacterial cultures in liquid and in solid media. Bacteria photosensitized with Hpr were subsequently exposed to laser beams and to daylight; then normal microbiological techniques were used to determine whether any bactericidal effect occurred. Satisfactory results were achieved, particularly against Gram-positive microorganisms; a partial inhibition of Gram-negative microorganisms was also observed.

Modulation of natural killer activity in mice by prolonged administration of various doses of dietary retinoids.

Groups of BALB/C mice received a diet supplement of 0 (group C), 200 (group A 200), 500 (group A 500), and 1,000 (group A 1,000) IU retinol palmitate (RP)/mouse/day in drinking water for 450 days. At progressive time intervals, mice from each group were tested for natural killer (NK) activity and for the percentage of large granular lymphocytes (LGL) in the spleen. In groups A 200, A 500 and A 1,000, a dose-dependent increase in NK activity was evident 50 days after the beginning of RP supplementation and was accompanied by a parallel increase of LGL number in the spleen. In group A 1,000, the increase of spontaneous or Poly I:C-induced cytotoxicity persisted until day 160. By contrast, inhibition of Poly I:C-induced NK cytotoxicity was found in this group at day 450.

Fluctuations of NK activity in human volunteers receiving vitamin A or a placebo daily.

This paper examines the effect of prolonged daily administration of Vitamin A on NK activity. A placebo and a pill containing 50,000 IU retinol acetate (RA) were taken daily for 120 days by 5 and 6 healthy volunteers respectively. NK activity was determined on days -45, -40, -30 and -10 to calculate each volunteer's inherent variability and then twice a month throughout the administration period. To minimize the experimental variability, an internal control was inserted in each assay. This consisted of two lymphocyte preparations from two healthy individuals divided into cryopreserved aliquots. The cytotoxicity percentage in each assay was corrected against these reference standards and converted into NK values by angular transformation. No increase in NK activity was noted during the study in the group receiving RA. A marked individual variability, however, was noted in both groups.