Trace element transfer from alginate dressings to wounds

ABSTRACT

A method has been developed for impregnating alginate-based wound dressings with trace elements required for wound healing and for quantifying the transfer from these dressing to wound fluid (for which a substitute—blood serum—was used in these experiments). Under ideal conditions, up to 85% can be carried across from the tow to the wound fluid.     

Chemical speciation in wound fluid leading to enhanced bioavailability for healing

ABSTRACT

ECCLES computer modelling is used to speciate Ca²⁺, Zn²⁺, Cu²⁺, Mn²⁺ and Fe³⁺ in wound fluid samples analysed for total metal content using Potentiometric stripping analysis. Bioavailability of metals, related to lipid soluble net-neutral complexes, was assessed and found to be broadly similar to the speciation in blood plasma. These appear to be benefits worthy of clinical investigation of keeping the wound fluid at pH = 6.4 and of raising the total cysteine concentration levels in wound fluid.     

Synthesis and applications of cyclopeptides and depsipeptides

Summary A solid phase protocol has been devised for the synthesis of linear precursors to cyclic depsipeptide analogues of dolastatin D.t-Butyldimethylsilyl groups were used for hydroxy group protection, with deprotection being carried out byt-butyl ammonium fluoride. HATU and PyBrop were successful in coupling highly hindered residues and in depside bond formation. Cyclic peptide analogues, cyclo[Arg-Gly-Asp-d-Phe-Lys(or Tyr)] have been synthesised and modified for use as carrier molecules for the transport of radio isotopes (¹¹¹In and¹²⁵I) into blood platelets as prototypes for medical imaging.     

A novel quantitative trait locus for Fusarium head blight resistance in chromosome 7A of wheat

A Chinese Spring-Sumai 3 chromosome 7A disomic substitution line (CS-Sumai 3-7ADSL) was reported to have a high level of Fusarium head blight (FHB) resistance for symptom spread within a spike (Type II) and low deoxynivalenol accumulation in infected kernels (Type III), but a quantitative trait locus (QTL) on chromosome 7A has never been identified from this source. To characterize QTL on chromosome 7A, we developed 191 7A chromosome recombinant inbred lines (7ACRIL) from a cross between Chinese Spring and CS-Sumai 3-7ADSL and evaluated both types of resistance in three greenhouse experiments. Two major QTL with Sumai 3 origin, conditioning both Type II and III resistance, were mapped in the short arm of chromosomes 3B (3BS) and near the centromere of chromosome 7A (7AC). The 3BS QTL corresponds to previously reported Fhb1 from Sumai 3, whereas 7AC QTL, designated as Fhb7AC, is a novel QTL identified from CS-Sumai 3-7ADSL in this study. Fhb7AC explains 22% phenotypic variation for Type II and 24% for Type III resistance. Marker Xwmc17 is the closest marker to Fhb7AC for both types of resistance. Fhb1 and Fhb7AC were additive, and together explained 56% variation for Type II and 41% for Type III resistance and resulted in 66% reduction in FHB severity and 84% reduction in deoxynivalenol (DON) content. Haplotype analysis of Sumai 3 parents revealed that Fhb7AC originated from Funo, an Italian cultivar. Fhb7AC has the potential to be used in improving wheat cultivars for both types of resistance.     

Growth factor stimulation of proliferating cell nuclear antigen (PCNA) in human breast epithelium in organ culture.

Normal human breast explants were maintained in serum-free culture for 7 days in the presence of either insulin hydrocortisone and cholera toxin (I/H/CT), epidermal growth factor (EGF) or transforming growth factor-alpha (TGF-alpha). Explants were labelled with [3H] thymidine, fixed in methacarn and processed for autoradiography. Parallel sections were immunolabelled with anti-PCNA antibody and analysed with a CAS 200 image analyser. Thymidine labelling index (TLI) and PCNA expression produced similar results with both indices increased in response to I/H/CT, EGF and TGF-alpha. In sections double labelled for PCNA and autoradiography the majority of labelled cells were positive for both markers.     

Purification of isopenicillin N synthetase.

Isopenicillin N synthetase was extracted from Cephalosporium acremonium and purified about 200-fold. The product showed one major protein band, coinciding with synthetase activity, when subjected to electrophoresis in polyacrylamide gel. An isopenicillin N synthetase from Penicillium chrysogenum was purified about 70-fold by similar procedures. The two enzymes resemble each other closely in their Mr, in their mobility on electrophoresis in polyacrylamide gel and in their requirement for Fe2+ and ascorbate for maximum activity. Preliminary experiments have shown that a similar isopenicillin N synthetase can be extracted from Streptomyces clavuligerus.     

Developmental expression and assembly of connexins into homomeric and heteromeric gap junction hemichannels in the mouse mammary gland

During the development of the mammary gland, duct-lining epithelial cells progress through a program of expansive proliferation, followed by a terminal differentiation that allows for the biosynthesis and secretion of milk during lactation. The role of gap junction proteins, connexins, in the development and function of this secretory epithelium was investigated. Connexins, Cx26 and Cx32, were differentially expressed throughout pregnancy and lactation in alveolar cells. Cx26 poly-(A)(+) RNA and protein levels increased from early pregnancy, whereas Cx32 was detectable only during lactation. At this time, immunolocalization of connexins by confocal microscopy and immunogold labeling of high-pressure frozen freeze-substituted tissue showed that both connexins colocalized to the same junctional plaque. Analysis of gap junction hemichannels (connexons) isolated from lactating mammary gland plasma membranes by a rate-density centrifugation procedure, followed by immunoprecipitation and by size-exclusion chromatography, showed that Cx26 and Cx32 were organized as homomeric and heteromeric connexons. Structural diversity in the assembly of gap junction hemichannels demonstrated between pregnant and lactating mammary gland may account for differences in ionic and molecular signaling that may physiologically influence the onset and/or maintenance of the secretory phenotype of alveolar epithelial cells.     

A Comparative Study of Candidal Invasion in Rabbit Tongue Mucosal Explants and Reconstituted Human Oral Epithelium

The purpose of this study is to compare the light and scanning electron microscopic (SEM) features of tissue invasion by three Candida species (C. albicans, C. tropicalis, and C. dubliniensis) in two different tissue culture models: rabbit tongue mucosal explants (RTME) and reconstituted human oral epithelium (RHOE). Tongue mucosal biopsies of healthy New Zealand rabbits were maintained in explant culture using a transwell system. RHOE was obtained from Skinethic Laboratory (Nice, France). RTME and RHOE were inoculated with C. albicans, C. tropicalis, and C. dubliniensis separately and incubated at 37 degrees C, 5% CO(2), and 100% humidity up to 48 h. Light microscopic and SEM examinations of uninfected (controls) and infected tissues were performed at 24 and 48 h. C. albicans produced characteristic hallmarks of pathological tissue invasion in both tissue models over a period of 48 h. Hyphae penetrated through epithelial cells and intercellular gaps latter resembling thigmotropism. SEM showed cavitations on the epithelial cell surfaces particularly pronounced at sites of hyphal invasion. Some hyphae on RTME showed several clusters of blastospores attached in regular arrangements resembling "appareil sporifere". C. tropicalis and C. dubliniensis produced few hyphae mainly on RTME but they did not penetrate either model. Our findings indicate that multiple host-fungal interactions such as cavitations, thigmotropism, and morphogenesis take place during candidal tissue invasion. RTME described here appears to be useful in investigations of such pathogenic processes of Candida active at the epithelial front.     

Errors in Quantitative Image Analysis due to Platform-Dependent Image Scaling

PURPOSE: To evaluate the ability of various software (SW) tools used for quantitative image analysis to properly account for source-specific image scaling employed by magnetic resonance imaging manufacturers. METHODS: A series of gadoteridol-doped distilled water solutions (0%, 0.5%, 1%, and 2% volume concentrations) was prepared for manual substitution into one (of three) phantom compartments to create “variable signal,” whereas the other two compartments (containing mineral oil and 0.25% gadoteriol) were held unchanged. Pseudodynamic images were acquired over multiple series using four scanners such that the histogram of pixel intensities varied enough to provoke variable image scaling from series to series. Additional diffusion-weighted images were acquired of an ice-water phantom to generate scanner-specific apparent diffusion coefficient (ADC) maps. The resulting pseudodynamic images and ADC maps were analyzed by eight centers of the Quantitative Imaging Network using 16 different SW tools to measure compartment-specific region-of-interest intensity. RESULTS: Images generated by one of the scanners appeared to have additional intensity scaling that was not accounted for by the majority of tested quantitative image analysis SW tools. Incorrect image scaling leads to intensity measurement bias near 100%, compared to nonscaled images. CONCLUSION: Corrective actions for image scaling are suggested for manufacturers and quantitative imaging community.