Application of a hydrodynamic model to microencapsulation by coacervation

The role of the hydrodynamic conditions in determining the characteristics of microcapsules made by coacervation was investigated in this study. The model proposed by Armenante and Kirwan, regarding the mass transfer to microcapsules in a turbulent agitated system, was applied. The working hypothesis was that the microcapsules are formed in microeddies generated by the agitation source. The dimensions of the microeddies, calculated in the vicinity of the agitation source according to Armenante and Kirwan, depend on the physical properties of the liquid medium and are inversely proportional to the power exchanged from the agitation source of the system. The power was determined according to the hydrodynamic rules developed by Rushton et al. The experimental results confirmed the hypothesis of the model. Indeed, a good relationship was found between the calculated size of the microeddies and the measured diameter of the microcapsules. Moreover, the distribution error (the standard deviation of the microcapsule size frequency distribution curve) was found to be proportional to the mean diameter value of the microcapsules and microeddies. This can be explained considering that the microeddies diameter increases by moving away from the agitation source and, consequently, a distribution of microeddies of difference sizes is present in the medium. The distribution error, which represents the difference between the smaller and the larger diameters, is inversely proportional to the exchanged power and, consequently, proportional to the mean diameter.     

Squamotransitional Cell Carcinoma of the Vagina: Diagnosis and Clinical Management A Literature Review Starting from a Rare Case Report

Primary squamotransitional cell carcinoma (STCC) is rare squamous cell tumor variant resembling transitional cell carcinoma (TCC) of the urinary tract. STCC occurs rarely in the vagina and its clinical and pathological correlates are poorly known. We report a unique case of a 66-year-old Italian woman with STCC of the vagina. A biopsy of the tumor was performed. The tumor qualified as a STCC. Following biopsy, the patient underwent radical hysterectomy (Piver’s III-type) with bilateral salpingo-oophorectomy, upper colpectomy, appendicectomy, peritoneal cytology, and lymphadenectomy. The patient is now healthy without evidence of recurrence at 30 months after surgery. Pathologically, cytoarchitectural characteristics distinguish this histotype (STCC) from conventional squamous cell carcinoma of the genital tract. The cytokeratin staining pattern (CK7 positive and CK20 negative), the p63 expression and the positivity for p16ink4a and high-risk HPV are the main elements of differential diagnosis. We suggest that STCC of the vagina should be treated by radical surgery, possibly followed by adjuvant therapy based on staging results and should receive a long-term follow-up.     

Fluorescent Magnetic Bioprobes by Surface Modification of Magnetite Nanoparticles

Bimodal nanoprobes comprising both magnetic and optical functionalities have been prepared via a sequential two-step process. Firstly, magnetite nanoparticles (MNPs) with well-defined cubic shape and an average dimension of 80 nm were produced by hydrolysis of iron sulfate and were then surface modified with silica shells by using the sol-gel method. The Fe₃O₄@SiO₂ particles were then functionalized with the fluorophore, fluorescein isothiocyanate (FITC), mediated by assembled shells of the cationic polyelectrolyte, polyethyleneimine (PEI). The Fe₃O₄ functionalized particles were then preliminary evaluated as fluorescent and magnetic probes by performing studies in which neuroblast cells have been contacted with these nanomaterials.     

Intraventricular hemorrhage in preterm infants: declining incidence in the 1980s

Ultrasound has been routinely used since late 1979 to diagnose periventricular-intraventricular hemorrhage in infants whose gestational age was 34 weeks or less. During the years 1980 to 1987 the ultrasound scans were interpreted by one person, and a steady decline in incidence of periventricular-intraventricular hemorrhage was observed. Both for infants of 34 weeks or less and for very low birth weight (less than 1500 g) infants, periventricular-intraventricular hemorrhage incidence decreased, respectively, from 34% and 39% in 1980 to 1981 to 19% and 25% in 1986 to 1987. This decrease was confined to true intraventricular hemorrhages, which decreased from 22% in 1980 to 1981 to 7% in 1986 to 1987 for infants of less than or equal to 34 weeks' gestation. These results were not influenced by a change in the distribution of birth weights or gestational ages of the infants evaluated nor by a change in the inborn to outborn ratio. The incidence of periventricular-intraventricular hemorrhage was lower in infants born by cesarean section than those delivered vaginally, but the decrease could not be attributed to an increased number of deliveries by cesarean section. Although there were undoubtedly changes in neonatal care during this time period, no planned intervention occurred. It was concluded that pharmacologic intervention studies must be interpreted with caution.     

Increased nucleated red blood cell counts in small for gestational age infants with very low birth weight

We evaluated the nucleated red blood cell (NRBC) counts in all infants with very low birth weight admitted to our neonatal intensive care unit from 1983 to 1986. There were 374 infants with birth weights of 500 g to 1500 g admitted in the first 24 hours after birth, but 31 died before studies were obtained. Of the remainder, 282 were appropriate for gestational age (AGA) and 61 were small for gestational age (SGA). Over 80% of both AGA and SGA infants were inborn and were evaluated within three hours of delivery. Nucleated red blood cell counts were significantly increased in SGA infants compared with AGA infants. The percent of infants with NRBC counts higher than 4.0 and 10.0 x 10(9)/L were 48% and 26%, respectively, in SGA infants compared with 19% and 6%, respectively, in AGA infants. Similarly, the percent of SGA infants with more than 40 or 100 NRBCs per 100 white blood cells were 62% and 36%, respectively, compared with 25% and 6%, respectively, in AGA infants. Data for specific weeks of gestation are provided and the differences were present at each gestational age. Recent data in fetuses with growth retardation, when blood was obtained directly from the fetal umbilical vein, showed an association between elevated NRBC counts and chronic hypoxemia. When increased NRBC counts are seen soon after birth, the possibility of a chronic intrauterine insult should be considered.     

Lupus anticoagulant positivity in insulin dependent diabetic patients: an additional risk factor in the pathogenesis of diabetic retinopathy?

AIMS: To investigate whether lupus anticoagulant (LA) positivity, a marker of endothelial dysfunction, might be relevant to the pathogenesis of diabetic retinopathy (DR). METHODS: 32 IDDM patients were examined for LA, fibrinogen, prothrombin (PT), PTT, prothrombin degradation products (F1+2), and activated protein C (APC). RESULTS: APC decreased and F1+2 increased significantly in LA positive but not in LA negative patients; 60% of LA positive and 18% of LA negative subjects had DR. PT, PTT, and fibrinogen levels were insignificant. CONCLUSION: These preliminary findings suggest that LA positivity could represent an additional risk factor for DR, acting as a link between the immunological and haemostatic systems.     

Concomitant effect of topical ubiquinone Q10 and vitamin E to prevent keratocyte apoptosis after excimer laser photoablation in rabbits

PURPOSE: To investigate in vivo whether ubiquinone Q10 together with vitamin E protects rabbit corneas from keratocyte apoptosis after excimer laser irradiation. METHODS: Photorefractive keratectomy (PRK) was performed in both eyes of three New Zealand white rabbits. During 3 days before surgery, each right eye received four-times-daily instillation of an eye-drop solution containing ubiquinone Q10 0.20% and vitamin E 0.04%; each left eye was treated with a solution that did not contain ubiquinone or vitamin E. The central cornea was analyzed after surgery using the in situ end labelling (ISEL) technique of nicked DNA to detect DNA fragmentation. To determine the number of ISEL positive nuclei, an average of 70 random microscopic fields (five for each de-epithelialized tissue section) of 138,000 mu2 were examined in the right and left cornea samples at 250X by two different observers. RESULTS: Light microscopic examination of the sections from corneas treated before PRK showed that cells committed to apoptosis by PRK were about 50% compared to those of untreated controls. CONCLUSION: Treatment of rabbit eyes before PRK with ubiquinone Q10 lowered the number of apoptotic events.     

Application of a hydrodynamic model to microencapsulation by coacervation

The role of the hydrodynamic conditions in determining the characteristics of microcapsules made by coacervation was investigated in this study. The model proposed by Armenante and Kirwan, regarding the mass transfer to microcapsules in a turbulent agitated system, was applied. The working hypothesis was that the microcapsules are formed in microeddies generated by the agitation source. The dimensions of the microeddies, calculated in the vicinity of the agitation source according to Armenante and Kirwan, depend on the physical properties of the liquid medium and are inversely proportional to the power exchanged from the agitation source of the system. The power was determined according to the hydrodynamic rules developed by Rushton et al. The experimental results confirmed the hypothesis of the model. Indeed, a good relationship was found between the calculated size of the microeddies and the measured diameter of the microcapsules. Moreover, the distribution error (the standard deviation of the microcapsule size frequency distribution curve) was found to be proportional to the mean diameter value of the microcapsules and microeddies. This can be explained considering that the microeddies diameter increases by moving away from the agitation source and, consequently, a distribution of microeddies of difference sizes is present in the medium. The distribution error, which represents the difference between the smaller and the larger diameters, is inversely proportional to the exchanged power and, consequently, proportional to the mean diameter.     

Epilepsy surgery in tuberous sclerosis: multistage procedures with bilateral or multilobar foci

Refractory seizures are common in patients with tuberous sclerosis and can contribute to developmental delay and behavioral problems. Surgical intervention can reduce the seizure burden in selected patients with tuberous sclerosis and refractory epilepsy, thereby improving cognitive function, behavior, and quality of life. However, the risks of surgery are usually considered unacceptable when the epileptogenic focus lies over dominant hemisphere eloquent cortex or is multilobar. Multistage invasive monitoring can provide detailed data regarding the location and number of ictal foci and functional extraoperative mapping can precisely delineate the boundaries of eloquent areas of the brain. If independent ictal onsets are demonstrated, a staged surgical approach can allow a more aggressive yet safe procedure in selected patients. A combination of staged resection and multiple subpial transections may provide an opportunity to treat epileptogenic foci located over eloquent cortex. Bilateral staged resections can be used when independent bihemispheric foci are present in patients with tuberous sclerosis. This article presents two cases, one of which (case 2) was previously reported, on successful multistage surgical treatment of epileptogenic foci located over an eloquent cortex or in both hemispheres in children with tuberous sclerosis. This case is represented since there is additional follow-up available and the prior report was to a neurosurgical audience. This multistage approach permitted resection of epileptogenic foci that would traditionally have been considered inoperable.