Drug release from heat-treated polyvinyl alcohol films

Polyvinyl alcohol (PVA) films containing 10% w/w of a model drug, sulphathiazole, were cast from aqueous solutions and subjected to heat treatment at specific temperatures for known periods of time. Heat treatment at temperatures above the T_g of the PVA films slowed down the rate of drug release from the films. Increasing the temperature of heat treatment from 120°C to 160°C further decreased the rate of drug release. On the other hand, if the heat treatment were conducted at a temperature below the T_g e.g. at 80°C, there were insignificant differences between the release profile of sulphathiazole from heat-treated films and that from untreated films. The duration of heat treatment affected the rate of drug release to a smaller extent compared to the temperature of heat treatment. These results correlated with the heat induced changes in the morphology of, and in the extent of water uptake by the PVA films.     

Correlates of osteopenia in patients with cystic fibrosis

The responses to heat shock in Tritrichomonas mobilensis, a squirrel monkey parasite and Tritrichomonas augusta, an amphibian trichomonad, were evaluated by means of metabolic labeling with [35S]methionine. Electrophoretically separated trichomonad proteins synthesized at different temperatures were visualized by autoradiography and the label incorporation quantitated by a trichloroacetic acid precipitation procedure. A considerable difference in thermotolerance between the two species was found as the protein synthesis reached a maximum at 41 C in T. mobilensis and 37 C in T. augusta. The latter tolerated temperature increases 13 C above normal cultivation temperatures as compared to only 4 C thermotolerance range above normal in T. mobilensis. Major heat shock proteins (Hsps) were expressed in both T. mobilensis (with apparent Mr 94, 72, and 58 kDa) and T. augusta (Mr 94, 70, and 56 kDa) as revealed by autoradiography. Western blot analysis with polyclonal antibody against DnaK of Escherichia coli showed the presence of antigenic Hsp70 homologs in both trichomonads. Similarly, a polyclonal antibody against Hsp60 with broad interspecies cross-reactivity detected Hsp60 homologs in both T. mobilensis and T. augusta. The anti-DnaK antibody cross-reacted with a T. mobilensis protein localized in Golgi apparatus as demonstrated by immunoelectron microscopy. Immunocytochemistry on trichomonad frozen sections revealed the presence of the Hsp60 homolog in light-microscopic granules corresponding to hydrogenosomes.     

Rapid Prototyping and Tooling of Custom-Made Tracheobronchial Stents

Rapid prototyping (RP) and rapid tooling (RT) techniques can be applied to the field of medicine primarily because of their ability to produce customised profiles and geometries in relatively short lead times. In this paper, the process by which these techniques can be applied for the production of customised tracheobronchial stents for the purpose of maintaining patency in an occluded respiratory tract is described. A comparison of RP systems was carried out to establish the preferred RP method to produce the master model. The vacuum casting RT process was then used to produce the stent.     

A comparison between intravenous iron polymaltose complex (Ferrum Hausmann) and oral ferrous fumarate in the treatment of iron deficiency anaemia in pregnancy

The costs of remedial work, and the radon level reduction achieved, have been studied in a series of domestic properties in Northamptonshire, which is a radon affected area. The cost-effectiveness of the series is similar to published theoretical estimates for proposed national remediation programmes, and five times more effective than our similar analysis for the National Health Service workplace, if it is assumed that 100% of householders discovering levels above 300 Bq m-3 implement remediation. In practice, in the UK, far fewer of those who arrange an initial radon test proceed to remediation, but this domestic programme could be cost effective if more than 5% carry out remediation. Our series confirms that a considerable number of householders with radon levels in the 200 to 300 Bq m-3 range do not seek or implement remediation work.     

Sulfur-containing compounds from Scorodocarpus borneensis and their antimicrobial activity

This paper reports two cases of neotropical echinococcosis caused by Echinococcus oligarthrus and E. vogeli, neither of which has been reported from Suriname. Case 1, a six-year-old boy, presented a 15 x 25 mm retro-ocular cystic tumor (observed by ultrasound, computed tomography scan, and magnetic resonance imaging) causing exophthalmia, chemosis, palpebral ptosis, and blindness of the left eye. Of two tentative diagnoses, Echinococcus cyst or dermoid tumor, the former was shown to be correct at surgery when a clear liquid and detached protoscoleces were aspirated. Rostellar hooks of the protoscolex were characteristic of E. oligarthrus. Case 2, a 41-year-old man, had polycystic masses excised from the liver and abdomen. A presurgery diagnosis of E. vogeli infection was made due to calcifications seen in the lesions, positive serology, residence of the patient in the tropical forest, and later by the size and shape of rostellar hooks. The presence of these two parasites in one of the former Guianas is not surprising; both species are endemic in tropical forest in Central and South America wherever people have not exterminated wild canids, especially the bush dog, (Speothos venaticus), and felids (wild cats of several species), along with pacas, agoutis, and other rodents that serve as intermediate host of these two cestodes. Eighty-six cases of polycystic echinococcosis are known in people from 11 countries from Nicaragua to Argentina: 32 due to E. vogeli, three to E. oligarthrus, and 51 for which determination of the species was not possible because the hooks of the protoscolex were not found or described. Research to elucidate aspects of transmission of E. vogeli and E. oligarthrus is of practical importance for defining measures for preventing the severe and frequently fatal illnesses caused by these two cestodes.     

Determination of 5-aminolaevulinic acid dehydratase activity in erythrocytes and porphobilinogen in urine by micellar electrokinetic capillary chromatography

A micellar electrokinetic capillary chromatographic (MECC) method has been developed and optimised for the separation of 5-aminolaevulinic acid (ALA) and porphobilinogen (PBG). The running buffer consisted of a mixture of 20 mM sodium phosphate and 20 mM sodium borate containing 50 mM sodium dodecyl sulphate (SDS) adjusted to pH 9.5 with 1 M NaOH. The running voltage and temperature were 20-25 kV and 30 degrees C, respectively. The MECC method for the analysis of PBG is fast and simple and is useful for the screening of PBG in the urine of patients suspected to have acute intermittent porphyria (AIP), and for the confirmation of lead exposure by measuring red-cell ALA-dehydratase (ALA-D) activity with ALA as the enzyme substrate.     

Two closely related adenovirus genome types with kidney or respiratory tract tropism differ in their binding to epithelial cells of various origins

The host cell interactions of the genome types Ad11p and Ad11a of human adenovirus serotype 11, displaying kidney or respiratory tropism, were compared using FACS analysis. Kinetic experiments indicated that the virus binding stated immediately and reached a plateau after 30 min. The binding of biotinylated virions to seven continuous cell lines. A549, A498, J82, HeLa, CHO, MDCK, and human diploid fibroblasts (HEDF), was quantitated by FACS analysis. The binding capacities of the two viruses to all human cell lines but A549 cells appeared to differ. Ad11p virions manifested high affinities, whereas Ad11a virions presented low affinities. Neither of the two viruses bound to CHO or MDCK cells. Reciprocal competition experiments showed that the Ad11a virions could be weakly blocked by the Ad11p virions, whereas the Ad11p virions could not be competed at all by the Ad11a virions. The binding of the Ad11p virions to cells could be blocked by the rfiber antiserum of Ad11p, but not by the corresponding antiserum against Ad11a or Ad35p. A comparison of the cytopathogenicity of the seven cell lines infected by Ad11p and Ad11a demonstrated that the efficiency of the initial event of an adenovirus infection directly affects the outcome of the viral infection. The Ad11a in the A498, J82, HeLa, or HEDF cells that presented lower affinity and receptor concentration showed 100 times less infectivity than that in A549 cells displaying high affinity and receptor concentration. These results indicate that the cell susceptibility to Ad11p and Ad11a infection strongly depends on both the number of fiber receptors on the host cells and the receptor affinity for ligands on the fiber knob. Our findings also suggest that the receptors for Ad11p and Ad11a on the surface of different cell types may be different or on different sites.     

Non-MHC-restricted cell-mediated lysis of human oligodendrocytes in vitro: relation with CD56 expression

Oligodendrocytes and their myelin membranes are the apparent target of the autoimmune response that characterizes the human adult central nervous system-demyelinating disease multiple sclerosis. Human oligodendrocytes do not express MHC class II molecules, a requirement for MHC-restricted injury mediated by myelin-reactive CD4+ T cells, the cell type implicated in initiating the disease process. In this study we observed that human adult central nervous system-derived oligodendrocytes can be susceptible to non-MHC-restricted lysis mediated by myelin basic protein-reactive CD4+ T cell lines. Cytotoxicity was significantly greater (37 +/- 4 vs 7 +/- 3%) with cell lines in which a high proportion of cells (mean, 28 +/- 6%) expressed CD56 compared with cytotoxicity mediated by low CD56 cell lines (8 +/- 2%). High CD56 cell lines, when rested in IL-2, lost cytotoxic activity and had reduced expression of CD56 (mean, 5 +/- 2%). CD4+ T cells isolated from short term (3-day) anti-CD3/IL-2-activated mononuclear cell cultures did not express CD56 and were not cytotoxic to oligodendrocytes unless lectin was added. In contrast, an enriched population of non-T cells extracted from the same activated MNC cultures expressed CD56 as well as other NK cell-associated surface molecules and was cytotoxic. These results indicate the potential susceptibility of human oligodendrocytes to non-MHC-restricted injury mediated by both Ag-reactive and nonspecific cellular immune effector cells, with CD56 expression being a common feature of the effector cells.