Screening for chickenpox in the UK: evaluation of a pre-conceptual screening program.
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Biomedical subjects
Publications and source records attributed to G Bignardi.
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The aim of this work was to prepare and evaluate a matrix for buccal drug delivery composed of a chitosan salt and poloxamer 407. Different chitosan salts were formed by reacting chitosan with acetic, citric, and lactic acid. Various proportions of poloxamer 407 were added to the aqueous solution of chitosan salt, and the residue obtained by lyophilisation was compressed into discs, using a 30 kN compression force. An experimental design (3(2)) was used to study the influence of the type of chitosan salt and of the relative amount of poloxamer on drug release capacity, swelling, erosion, and mucoadhesiveness of matrices. The results showed that matrix properties depended significantly on both relative amount of poloxamer and chitosan salt type. The rank orders of chitosan salts for the four processes evaluated were as follows: drug release: chitosan acetate>chitosan citrate>chitosan lactate; swelling: chitosan lactate>chitosan acetate=chitosan citrate; erosion: chitosan citrate>chitosan lactate>chitosan acetate; mucoadhesion: chitosan lactate>chitosan acetate=chitosan citrate. Mucoadhesion was particularly favoured when poloxamer 407 was present at about 30% (w/w). The matrix composed of chitosan lactate and poloxamer 407 showed the best characteristics for buccal administration.
Two cases of infection with Panton-Valentine Leukocidin (PVL) producing strains of Staphylococcus aureus are reported. A 15-year-old insulin dependent diabetic developed toxic shock syndrome and an abscess in the deep tissue around his left hip. A 34-day-old infant presented with a right orbital cellulitis with an intra-orbital collection and septicaemia. In both cases PVL-producing strains of Staphylococcus aureus were isolated. Both surgery and prolonged antibiotic combination regimens were required to eradicate the infection. The cases reported here demonstrate the wide range of clinical presentations seen with PVL producing strains, which have so far been mainly associated with furuncles and necrotising pneumonia.
We report four cases of listeriosis that occurred over a two-month period in north east England. Due to the apparent nosocomial acquisition of infection and the clustering of cases in time and place, extended epidemiological investigation was performed and the outbreak was traced to a caterer who was providing sandwiches for hospital shops. We discuss the difficulties in preventing food-borne listeriosis in the hospital setting.
Retinoic acid (RA) is employed in the therapeutic treatment of acute promyelocytic leukemia (APL). In this paper, the chemical stability and the most favorable storage conditions of RA in hard gelatin capsules containing alpha-lactose monohydrate, used in clinical experimentation, are reported. A secondary goal of this work was to show the usefulness of a robust regression technique, repeated median with replicates (RMWR) in a solid-state shelf life prediction by accelerated studies. The capsules were stored at room temperature and in the freezer. Their residual RA content was assayed for more than 3 years. RA chemical degradation was monitored by high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) stability-indicating methods previously validated and able to detect various potential degradation products. Possible physical modifications were checked by dissolution tests and differential scanning calorimetry (DSC) of the content of the capsules. The shelf life was also predicted by an accelerated isothermal method to confirm room temperature results, and the activation energy estimated through this study was 12.5 +/- 1.1 kcal/mol (95% confidence interval). In the conditions of climatic zone II, the shelf life for the capsules stored at room temperature in light-resistant containers was equal to 678 days, while the capsules stored in the freezer retained the initial content of drug after 1289 days. From the results gathered in this study, the usefulness of RMWR for shelf life prediction in the presence of outliers is evident.
For oral delivery of antimicrobial and anti-inflammatory drug, mucoadhesive tablets based on gelatin/hydroxypropylcellulose (HPC), gelatin/hydroxypropylmethyl-cellulose (HPMC), and gelatin/sodium carboxymethylcellulose (NaCMC) at different ratios were prepared by direct compression of the mixed powders. Metronidazole and benzydamine were used as model drugs. The in vitro bioadhesive properties, evaluated by a commercial tensile tester, were significantly affected by the model substrate employed, that is, a polypropylene (PP) membrane or a biological membrane (eggshell membrane). The use of the biological substrate seemed to supply more reliable data. All studied formulations showed an erosion-diffusion mechanism of release, anomalous or non-Fickian release, in agreement with the behavior of the swellable systems.
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A survey was carried out by personal interview to assess the awareness of basic food hygiene and food safety amongst 77 HIV-positive individuals attending a single hospital. There was some confusion and lack of knowledge about aspects of food storage and despite the fact that 74% of subjects had modified their diet since learning their HIV status (mainly for nutritional reasons) only 25% reported receiving information on food safety. Of the subjects interviewed 96%, 66% and 23% were aware of the risks of infection from Salmonella, Listeria monocytogenes and Cryptosporidium, respectively; although most were not aware of the UK Government's advice on the consumption of eggs, soft cheese, pâté and cook-chill foods. Over 40% of those interviewed reported that they did not drink tap water (most drank bottled water instead), but few were aware of infections potentially transmitted through water. Although pets represent a potential source of a wide variety of infectious agents, there was a high level of awareness of this problem. This study highlights the need for improving the availability of information on food hygiene and infections acquired through food and water to HIV-positive individuals.
The interaction between dithranol and heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (TMBCyD) has been investigated in aqueous solution containing isoascorbic acid (0.2% w/v) as antioxidant and in the solid state. The interaction in the solid state was studied by differential scanning calorimetry (DSC), infrared spectroscopy (IR), X-ray powder diffractometry (XPD) and a dissolution-rate method. The extent of complexation between the two substances was poor, as indicated by the low value of the slope of the linear part of the solubility curve. A phase diagram was constructed by measuring the thermal behaviour of various re-solidified physical mixtures of dithranol and of TMBCyD previously subjected to heating until melting of the TMBCyD. The loss of dithranol, owing to sublimation and degradation caused by the thermal treatment used, was less than 10%. In keeping with XPD and IR data, the phase diagram indicated that a complex was formed containing 13.7% dithranol (molar ratio 1:1) which had a congruent melting point at 164 degrees C. The drug dissolution rate from the 1:1 complex was measurable, unlike that of the corresponding physical mixture, and was significantly increased when the complex was dispersed in the glassy matrix of TMBCyD, as it was in re-solidified mixtures containing 2-7% dithranol. The results show that the solubility of dithranol is increased significantly as a consequence of its interaction with TMBCyD, despite the low extent of complexation between the two substances.
Oligella urethralis is an organism which is normally isolated as a commensal from the genitourinary tract. We describe the first two reported cases of CAPD-associated peritonitis caused by this organism. Both isolates were found to be resistant to ciprofloxacin, while relatively sensitive to a wide range of antimicrobial drugs. These findings indicate that this organism may be an opportunistic pathogen for CAPD patients, and that extensive ciprofloxacin usage provides a selection pressure for emergence of resistance.
The classical isothermal approach for the prediction of drug stability exploits least squares regression. In this paper the use of some robust regression techniques to estimate the rate constants at different temperatures has been evaluated. These techniques are able to give accurate estimates when data are contaminated by the presence of outliers. The successful application of two robust methods, single median and repeated median, to real stability data from the literature is shown. Moreover, the authors have modified the original methods in order to apply them to data sets with replicates, typical of stability studies. The performances of the modified techniques have been investigated with simulated data sets containing outliers and with real data. They appear suitable for preliminary stability studies, especially on solid dosage forms. For a quick implementation of these methods, macroprograms written for a widely used spreadsheet are reported.
A case of pyrexia of unknown origin in a 35-year-old man, who had become a father nine months earlier, is presented. A diagnosis of cytomegalovirus mononucleosis was achieved only after extensive investigations. It is suggested that cytomegalovirus mononucleosis should be added to the differential diagnosis when investigating pyrexia of unknown origin in fathers of young children.
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A case of Nocardia asteroides pneumonia was diagnosed after death in a patient with AIDS. Six sputum cultures and one bronchoalveolar lavage fluid contained no pathogens, and no growth was obtained from one pleural fluid aspirate. None of these specimens was incubated for more than two days. Extended incubation for mycobacteria also failed to help in the diagnosis. N asteroides was isolated from pus taken from the lung cavity during the post mortem examination. It is suggested that if nocardiosis enters the differential diagnosis all specimens should be cultured for at least two weeks and the use of selective media be considered. This case highlights the need for clinicians to maintain a high index of suspicion for this pathogen.
The reaction of N,N-disubstituted open-chain and cyclohexane alpha-aminomethyleneketones (I) and (II) with p-toluenesulfonyl (tosyl) isocyanate gave amino-disubstituted 2-acyl-3-amino-N-tosylpropenamides (III) and/or N,N-(3-amino-1-alkyl-2-propenylidene) and N,N-[2-(aminomethylene)-cyclohexylidene] tosylamides (IV) and (V), the final product being related to the carbon and nitrogen substituents of the enaminone. The evaluation of the hypoglycemic activity concerning some of the above compounds gave no interesting results.
The synthesis of N,N-disubstituted 3-aminomethylene-5-hydroxy-2,2-dimethyl-7-pentyl-4-chromanones (III) and their reaction with dichloroketene are described. The resulting cycloadducts (IV) gave, by dehydrochlorination, the N,N-disubstituted 4-amino-3-chloro-10-hydroxy-5,5-dimethyl-8-pentyl-2H,5H-pyrano[3,2-c] [1]benzopyran-2-ones (V), which are structurally related to tetrahydrocannabinols. Only the compound (V a) displayed a very weak stimulant activity on the CNS.
Relationship between chemical structure, hemolytic action and surface activity of five glucosides of oleanolic acid were studied. Monodesmosidic saponins are more hemolytic than bisdesmosidic. The hemolytic activity of monodesmosides decreased with the length and the branching of the glucosidic chain. Surface activity is major in bisdesmosides. This property increases with the length of the glucosidic chain in monodesmosides. Increase of hemolytic action is accompanied by a decrease of surface activity.