Evaluation of enzyme stability during preparation of polylactide-co-glycolide microspheres

This work was aimed at studying enzyme prolidase stability and its interactions with the reagents and the process conditions involved in preparation, by an emulsification process, of prolidase loaded poly(lactide-co-glycolide) (PLGA) microparticulate systems. Enzyme stability was tested with respect to contact with methylene chloride, ethyl acetate, PLGA polymers, and several agents used as emulsifiers such as polyvinyl alcohol (PVA), polyvinyl pyrolidone (PVP), carboxymethyl cellulose (CMC) and sodium oleate (NaOl). Enzyme stability to temperature and mechanical stirring was also evaluated. Prolidase-loaded PLGA microspheres were prepared and evaluated in terms of protein activity. The results obtained showed that the prolidase-loaded PLGA microspheres can be prepared only upon enzyme stabilization by addition of both BSA and MnCl(2) into its TRIS solution. Methylene chloride was the suitable organic solvent to be used in the double emulsion process, together with PVA as dispersing agent in the outer aqueous phase. Low temperatures during the emulsification step and very short process times are recommended, in order to maintain enzyme activity at its maximum. In these conditions spherical microspheres were obtained, releasing active prolidase for up to 15 days.     

Cerebral hemispheric differences in memory of emotional and non-emotional words in normal individuals

The present study was designed to examine the cerebral hemispheric differences in memory of positive, negative and non-emotional words using a new method of successive presentation to each visual half-field in which perception of each item was nearly perfect thereby allowing laterality differences for effects of emotion on memory to emerge unconfounded by perception (Experiment 1). This procedure was compared with traditional perceptual identification (Experiment 2). In Experiment 1, 12 words were presented successively in each half field in each trial followed by free recall at the end of the trial. The results showed that recall of positive and negative emotional words was better than that of non-emotional words in both visual fields. Recall of positive and negative emotional words was not different in left and right visual fields (RVFs) although the recall of non-emotional words was better in the RVF than in the left visual field (LVF). The differences in recall between emotional and non-emotional words was greater in the LVF than in the RVF. Experiment 2 used the more traditional method of perceptual identification following each visual half-field presentation of a single item. Perceptual identification was better in the RVF than the LVF in each word condition. There were no visual field differences in perceptual identification between emotional and non-emotional words, as there was for memory in Experiment 1. The results supported the hypothesis that explicit memory for emotional words was dependent more on the right hemisphere, whereas perception of both emotional and non-emotional words was more dependent on the left hemisphere.     

δ13CO2 Excretion and Expression of Dyspeptic Symptoms in Patients Evaluated for Helicobacter pylori Infection by [13C] Urea Breath Test

Previous studies showed that either the urease activity possessed by H. pylori and the bacterial load may influence the results of the [¹³C] urea breath test. However, the correlation between urease activity and dyspepsia is unclear. The aim of our study was to evaluate whether the urease activity of the gastroduodenal tract may influence the severity of dyspeptic symptoms. In all, 2520 dyspeptic patients (1109 men, 1411 women; mean age 47 ± 16 years) without gastroesophageal reflux disease, diabetes, vascular disorders, liver and biliary tract diseases, and tumors of the gastrointestinal tract and with a normal appearing abdominal ultrasonography were enrolled. All these patients underwent a [¹³C] urea breath test and filled out a questionnaire on dyspeptic symptoms. Subjects were divided in five different groups according to delta over baseline (DOB) values (group 1 < 3.5, group 2 = 3.5–6; group 3 = 6.1–11, group 4 = 11.1–23, group 5 > 23.1). The prevalence and intensity of dyspeptic symptoms were compared among groups. In all, 1688 patients (67%, 928 females and 760 males; mean age 48 ± 15 years) were H. pylori-positive. The chi-squared test and analysis of variance showed increase of frequency and intensity of each dyspeptic symptom according to DOB values. In conclusion, Dyspepsia may parallel gastric urease activity. However, whether higher DOB values are related to higher bacterial load or, alternatively, to the presence of particular H. pylori strains able to produce larger amounts of urease is uncertain.     

High-grade congenital esophageal stenosis owing to a membranous diaphragm with tracheoesophageal fistula

Gross E-type congenital esophageal atresia associated with congenital esophageal stenosis is extremely rare. In a male infant born at 36 weeks of gestation, bubbly vomiting was noted after birth. X-ray films of the chest and abdomen showed coil-up sign of the nasogastric tube and gas in the stomach and small intestines were recognized, so gross C-type esophageal atresia was suspected and surgery was performed on the first day of life. Surgery revealed the presence of a tracheoesophageal fistula in the upper esophagus and membranous stenosis on the distal side.