Encapsulation of various recombinant mammalian cell types in different alginate microcapsules

Microencapsulation of recombinant "universal" cells with immunoprotective membranes is an alternate approach to somatic gene therapy. Therapeutic gene products secreted by these cells can be delivered to different patients without immunosuppression or genetic modification of the host's cells. The encapsulation of different mammalian cell types (epithelial cells, fibroblasts, and myoblasts) is compared among three alginate-based microcapsules: (1) calcium-linked alginate microcapsules with a solubilized core and a poly-L-lysine-alginate-laminated surface; (2) barium-linked alginate beads with a gelled core; and (3) a hybrid formulation of barium-linked alginate beads with a poly-L-lysine-alginate-laminated surface. The mechanical stability of the different microcapsule types, as measured with a cone-and-plate shearing apparatus, was superior in the two barium-linked alginate beads. All cell types maintained high viability (65-90%) in culture after encapsulation. The recombinant gene products secreted by these cells (human growth hormone MW = 22,000, human factor IX MW = 57,000, and murine beta-glucuronidase MW = 300,000) were able to traverse the three microcapsule types at similar rates. Cell numbers within the microcapsules increased twofold to > 20-fold over 4 weeks, depending on the cell type. Epithelial and myoblast cell numbers were not affected by microcapsule formulation; however, fibroblasts proliferated the most in the calcium-linked alginate spheres. These results show that for culturing fibroblasts in a mechanically stable environment the classical calcium-linked microcapsules are adequate. However, where mechanical stability is a more critical requirement, the solid barium-linked gelled beads are more appropriate choices.     

Correlation between Down's syndrome and malformations of pediatric surgical interest

PURPOSE: This is a collaborative study carried out by Pediatric Surgeons of the "G.D'Annunzio" University and the Regional Association of Down Children of Abruzzo (Italy). METHODS: Data were collected of malformations combined with Down Syndrome (DS) during a 10-year period in a population of defined age to look for a possible improvement of the patients' life conditions. Reportedly, 50% of these patients may reach an age of about 60 years. RESULTS: One hundred twenty-seven DS subjects from this region were evaluated, 54% of whom had associated malformations (13% cardiac, 41% extracardiac, and 13% both). Seventeen patients of 53 underwent surgery for extracardiac malformations, with gastrointestinal malformations prevailing. The largest number of DS babies were born from mothers under 30 years of age; this is attributed to the largest birth rate and the least prevention at this age. Mothers older than 38 years gave birth to DS babies with the lowest rate of associated malformations. CONCLUSION: The role of the pediatric surgeon in multidisciplinary assistance for DS patients is stressed.     

Usefulness of blood and plasma viscosity measurements in the evaluation of arteriopathic patients

Blood viscosity represents the internal friction of the blood, in other terms, its resistance to be deformed and to flow under a tangential force. This function is conditioned by the intrinsic characteristics of blood and the geometry of the system in which flow occurs. Thus, any in vitro (or ex vivo) system of measurement of blood viscosity represents a relatively approximate evaluation of the ratio between intertial forces and viscous resistance. However, the possibility of measuring blood viscosity in a reproducible way provided the opportunity of identifying some clinical conditions associated with a worsening in rheologic parameters. Thus, "primary" and "secondary" hyperviscosity syndromes have been defined, on the basis of the pathogenetic responsibility of rheologic or hemodynamic factors, respectively. The possibility of performing in vitro measurement of blood viscosity provided the opportunity of planning several clinical pharmacology studies with theoretically active drugs. On such a basis, the rationale has arisen for a "rheologic therapy" of circulatory disturbances. Moreover, the evaluation of rheologic parameters is extremely useful since epidemiological studies have shown that viscosity may represent a marker and a prognostic factor for the progression of ischemic diseases as well as an independent risk factor, thus suggesting the opportunity of performing controlled clinical studies to evaluate the impact of hemorheological changes in the prevention of cardiovascular events.     

Fair Adaptive Cross-Layer Resource Allocation Scheme for IEEE 802.16 Broadband Wireless Networks

In a WiMAX network, the Medium Access Control (MAC) protocol deals with resource allocation to different types of traffic. The key components that ensure Quality of Service (QoS) guarantees in a WiMAX network include Call Admission Control (CAC), Bandwidth and Burst allocation. In this Paper, a Cross-layer framework is designed to efficiently allocate resources to various classes of traffic. CAC and Bandwidth allocation are dealt in the MAC layer, while Burst allocation in the PHYsical layer. The predominant goal of this work is to reduce delay and Information Element (IE) overheads by efficiently utilizing the available frame space. The History based CAC (HCAC) proposed in this paper deals with call acceptance based on the Contention Window (CW) values. The History based Bandwidth Allocation (HBA) scheme deals with allocating bandwidth based on Consumption and Equity measures. The proposed tightly coupled Delay Tolerance based Scheduler (DTS) and Bucket based Burst Allocator (BBA) allocate resources by prioritizing flows with least delay tolerance. It is seen that the proposed schemes offer better performance in contrast to the existing benchmarked schemes in terms of Throughput, Average Delay and Packet Loss Ratio (PLR).

     

Wolff-Parkinson-White, a study on the prevalence of the site of accessory pathways: relations between stability of pre-excitation, symptoms, cardiac arrhythmias and association of mitral valve prolapse with localization of pre-excitation

The aim of this study was to evaluate the prevalence of the anatomic site of accessory pathways using surface electrocardiogram in patients affected by Wolff-Parkinson-White (WPW), and compare it to the stability of preexcitation, symptoms, incidence of arrhythmias, and the possible association of mitral valve prolapse with the localization of preexcitation. From March 1992 to August 1993 at the Cardiology Service of the Civil Hospital "Augusto Murri" in Fermo, USL 21 of the Marche Region, a total of 40 subjects suffering from WPW syndrome were examined prospectively (28 males and 12 females aged between 13 and 75 years). Using surface ECG to evaluate the axis of the delta wave in 12 standard derivations, the authors identified the anatomic site of the accessory pathways. Preexcitation stability was analysed for each patient together with the reported symptoms and the various forms of arrhythmia using dynamic ECG and effort ECG performed using a cycloergometer. Wherever possible an echocardiogram was performed to identify the possible presence of mitral valve prolapse. Out of a total of 40 patients the authors identified 3 cases with an accessory right antero-septal pathway, 13 with an anomalous postero-septal fasciculus, 11 with a right lateral and 13 with a left lateral anomaly. The statistical analysis of data revealed the stability of pre-excitation in 52.5% of cases 55% of patients were found to have a positive record with regard to past symptoms, and supraventricular or ventricular cardiac arrhythmia were diagnosed in 52.5% of the patients examined.(ABSTRACT TRUNCATED AT 250 WORDS)     

K-band high-pressure cell for ENDOR studies

This article describes a versatile high-pressure K-band EPR-ENDOR system, designed for the examination of the effects of hydrostatic pressure on F-center hyperfine interactions. Dielectric filling is used to minimize the inner dimensions of the pressure cell. Cavity mode and coil geometry permit the same system to be used either for high-frequency field modulation EPR or for ENDOR by rotating the magnetic field. The pressure seal is also part of a rotatable microwave joint permitting the microwave coupling to be varied by rotating the cavity-pressure cell assembly. The beryllium-copper high-pressure vessel is separated from the pressure generating device by high-pressure transmitting tubing. It has been tested to 18 kilobars.     

A systematic approach to the discovery of new proteins of ultrastructural interest

A systematic approach to the discovery of new proteins of ultrastructural interest is discussed. It involves the merging of monoclonal antibody technology with immunocytochemical technology, particularly immunoelectron microscopy. In this approach, monoclonal antibodies are raised to a cellular preparation that can be grossly heterogeneous in its protein composition. The hybridoma culture fluids are screened by immunocytochemistry for the ultrastructural localization of their antibodies. Those monoclonal antibodies that show specific ultrastructural localizations of interest are then selected for further investigation. The antigen to which a given monoclonal antibody is directed is then identified by immunoprecipitation and immunoblotting with that antibody. By this approach, two new striated muscle proteins of ultrastructural interest have been discovered and are named zeugmatin and enactin. The former is a protein of over 500 kD localized by immunoelectron microscopy to the Z-bands, the latter of 245 kD localized to the N₁ line of striated muscle.     

Lensed optical fiber sensors for on-line measurement of flow

This paper describes a system using lensed optical fiber sensors that are arranged in the form of two orthogonal projections. The sensors are placed around a process vessel for upstream and downstream measurements. The purpose of the system is for on-line monitoring of particles and droplets being conveyed by a fluid. The lenses were constructed using a custom heating fixture. The fixture enables the lenses to be constructed with similar radii resulting in identical characteristics with minimum differences in transmitted intensity and emission angle. By collimating radiation from two halogen bulbs, radiation can be obtained by the sensors with radiation intensity related to the nature of the media. Each sensor interrogates a finite section of the measurement section. Each sensor provides a view. Parallel sensors provide a projection. Signal processing is carried out on the measured data in the time and frequency domains to investigate the latent information present in the flow signals.     

Comparative bioavailability of two enteric-coated capsules of omeprazole in healthy volunteers

A comparative bioavailability study was carried out on two enteric-coated capsules (20 mg each) of omeprazole (omeprazole, Alembic: "A" and Losec, Astra, England: "B"). The in-vitro dissolution of both products "A" and "B" met the prescribed USP standard. The bioavailability of single dose (20 mg) and multiple doses (20 mg once daily for 7 days) of both products "A" and "B" were carried out in eight healthy male volunteers in a crossover design. The rate and extent of bioavailability of omeprazole was higher in product "A" following a single oral dose, suggesting its therapeutic advantage over the product "B" in the prevention of acid aspiration during surgery. In multiple dose study, the two products were found bioequivalent as assessed by AUC0-infinity, Cmax, tmax and t1/2 elimination.