Contrast enhancement using curd and contrast agent mixtures for ex vivo vessel imaging in computed tomography.

We describe a cheap and efficient method for filling the vascular space of ex vivo tissue samples with a radiopaque material that can be used in computed tomography imaging. The filling material consists of curd, water, and a radiological contrast agent. Viscosity ranges and the degree of attenuation of X-rays of the filling material can be easily adjusted to the requirements of a specific application. The method is non-destructive and without negative effects on subsequent histological examinations.

Dual energy CT myelography after lumbar osteosynthesis.

PURPOSE: The purpose of this study was to evaluate the benefits of CT myelography in the DE technique in patients with lumbar osteosynthesis. MATERIALS AND METHODS: In 30 patients a DE-CT scan of the spine with tube voltages of 80 kV and 140 kV was performed and a virtual monochromatic series of 120 kV was generated after intrathecal contrast injection. The impact of metal artifacts on the spinal canal and the spinal foramina was evaluated. The visualization of nerve roots was compared between a VRT series of the dural sac and conventional myelography. RESULTS: With tube voltages of 140 kV, the artifacts were least pronounced. As no overlay disturbance was present, VRT visualization of the nerve roots was more reliable than conventional myelography. CONCLUSION: In patients after osteosynthesis, CT in the DE technique provides minimal artifact disturbance using a tube voltage of 140 kV. "Virtual myelography" seems to be superior to conventional myelography for the evaluation of nerve roots. This could reduce additional conventional radiography, may shorten the entire examination and radiation time and diminish unnecessary painful movements for the patient.

[Adhesive strength of a ß-tricalcium phosphate-enriched bone adhesive]. / Haftfestigkeit eines mit ß-Trikalziumphosphat angereichertem Knochenadhäsivs.

BACKGROUND: This investigation describes experimental tests of the biomechanical features of a new resorbable bone adhesive based on methacrylate-terminated oligolactides enhanced with osteoconductive ß-tricalcium phosphate. MATERIAL AND METHODS: 51 New Zealand white rabbits were randomised to an adhesive group (n = 29) and a control group (n = 22). An extra-articular bone cylinder was taken from the proximal tibia, two stripes of adhesive were applied and the cylinders were replanted. After 10 and 21 days, 3 and 12 months tibial specimens were harvested and the cylinder pull-out test was performed with a servo-hydraulic machine. Additionally the pull-out force was evaluated with the bone-equivalent Ebazell® after 5, 10 and 360 minutes in 14 specimens each. RESULTS: Average pull-out forces in the adhesive group were 28 N after 10 days (control: 57 N), 155 N after 21 days (216 N), 184 N after 3 months (197 N) and 205 N after 12 months (185 N). Investigations with Ebazell® showed almost identical pull-out forces after 5 min, 15 min and 360 min. Adhesive forces were as high as 125 N/cm (2) of adhesive surface and more than 1200 N/g of adhesive mass. CONCLUSIONS: The adhesive investigated here has a very good primary adhesive power, compared to the literature data, achieved after only 5 minutes. Even in moist surroundings the adhesive capacity remains sufficient. The adhesive has to prove its resorptive properties in further investigations and in first line its medium-term and long-lasting biocompatibility. Furthermore, biomechanical features will have to be compared to those of conventional fixation techniques.

Lung transplantation in the Fischer 344-->Wistar Kyoto rat strain combination is not suitable to study bronchiolitis obliterans.

BACKGROUND: To elucidate the pathogenesis of bronchiolitis obliterans (BO) a reliable animal model is needed. According to the literature, lung transplantation from Fischer 344 (F344) to Wistar Kyoto (WKY) rats is the only model that reliably results in BO without a further stimulus. METHODS: We performed orthotopic left lung transplantation in F344 to WKY rats and in both isogeneic rat strain combinations. Suture and cuff techniques for anastomosis were compared. The time course of rejection and the morphology of the bronchial anastomoses were documented by repeated flat-panel volumetric computed tomography (fpVCT) in the living animal. Graft histopathology was analyzed 3 months post-transplant. RESULTS: According to the graft outcome, as revealed by fpVCT, grafts were sub-divided into two groups: In Group 1, infiltrates due to acute rejection occurred early after transplantation and resolved thereafter. Graft histopathology showed minor changes but no BO. In Group 2, acute rejection caused total atelectasis that never resolved. After 3 months, grafts were shrunken and exhibited tissue remodeling with some similarities to BO. No correlation between graft outcome and anastomotic technique was apparent. CONCLUSIONS: Modeling lung transplantation using the F344-to-WKY combination is without clinical relevance because BO does not develop in grafts with life-sustaining function. Consecutive fpVCT is useful to monitor pathologic changes in rat pulmonary grafts.

Dietary oral exposure to l,3,5-trinitro-1,3,5-triazine in the northern bobwhite (Colinus virginianus).

The potential risk to wildlife from exposure to explosives, including 1,3,5-trinitro-1,3,5-triazine (RDX), has been an issue at numerous U.S. military installations where these substances are found in soil and water. Presently, no data describing the effects of RDX exposure in avian species exist. Therefore, an acute lethal dose (ALD) and 14- and 90-d subchronic dietary exposures to RDX were evaluated in a species potentially present at many contaminated sites, i.e., the northern bobwhite (Colinus virginianus). The ALDs for females and males were 187 and 280 mg/kg, respectively. Data from the 14-d dietary trial suggested that RDX exposure inhibited food consumption, weight gain, and egg production. Dietary RDX exposure for 90-d produced a dose-dependant decreasing trend in total feed consumption, total egg production, and hen-housed production parameters. These collective data suggest that quail may respond differently to oral RDX exposure compared with mammals.

[Quality control of labile blood products. Why and howto properly take a specimen? Labile Blood Products Group of the French Blood Transfusion Society]. / Le contrôle de qualité des produits sanguins labiles. Pourquoi et comment bien prélever un échantillon? Groupe de produits sanguins labiles de la Société française de transfusion sanguine.

This article reviews the various techniques of sampling used for the quality control of blood cell products. The importance of this stage for the validity of quality control results is emphasized. Three sampling methods, i.e., stripping, the sterile connection of sampling bag and the destructive method, are described in the form of operating modes and analyzed according to their advantages and drawbacks. The results of a comparative study carried out by the working group 'Blood Cell Products' of the French Society of Blood Transfusion are presented, showing that each method is valid and permits one to obtain a representative sample of the product to be controlled. Thus the diversity of the sampling methods allows us to select the one most adapted to the product to be controlled and to the analyses to be carried out afterward.

Protection of mice against SV40 tumours by Pam3Cys, MTP-PE and Pam3Cys conjugated with the SV40 T antigen-derived peptide, K(698)-T(708).

The intraperitoneal injection of Balb/c mice with synthetic analogues of adjuvants S-[2,3-bis(palmitoyloxy)-(2-RS)-propyl]-N-palmitoyl-R-cysteine (Pam3Cys) or muramyltripeptide phosphatidylethanolamine (MTP-PE) inhibited the tumourigenic growth of subcutaneously injected VLM cells, a syngeneic simian virus 40 (SV40)-transformed cell line. Furthermore, the Pam3Cys conjugate of K698-T708 (KT), which represents the C-terminal undecapeptide of the SV40 large tumour (T) antigen, was tumour-protective. Also syngeneic spleen cells, preincubated in vitro with this Pam3Cys-KT derivative, which anchores spontaneously at the cell membrane, were, through SV40 tumour mimicry, tumour-protective. The protection was impaired by treatment of the mice with either anti-CD4, anti-CD8 IgG, anti asialo GM1 antiserum or dextrane sulfate, which deplete the CD4+, CD8+ and NK cells or the macrophages, respectively. In summary, SV40 tumour transplantation resistance can be experimentally elicited by a tumour-epitope-specific vaccine. In the absence of an immunogenic epitope protection was obtained by administration of biological response modifiers. Protection is effected by SV40-T-antigen-specific cytotoxic lymphocytes in cooperation with NK cells and macrophages.

IgG-antibodies to CNS proteins in patients with multiple sclerosis.

The CSF and sera of 185 patients with multiple sclerosis (MS), 130 patients with other inflammatory diseases of the CNS (OID) and 50 patients with spinal disc syndrome (controls) were investigated for IgG-antibodies to CNS proteins by SDS-PAGE and immunoblotting and by isoelectric focusing combined with affinity blotting. IgG-antibodies to CNS proteins in serum (immunoblotting) were detected in 18 patients with MS (10%), in 29 patients with OID (22%) and in four controls (8%). Intrathecal synthesis of IgG-antibodies to CNS proteins was demonstrated in 11 patients with MS (6%), in 37 patients with OID (28%) and in none of the controls. In 4/11 patients with MS intrathecally produced antibodies were shown to be specific for glial fibrillary acidic protein (GFAP). Of patients with MS, 180 displayed oligoclonal IgG-bands in the CSF. Specificity of these bands for CNS proteins was demonstrated only in 2/180 specimens (1%). These findings indicate, that in most patients with MS oligoclonal IgG-bands in the CSF do not contain relevant amounts of antibodies to CNS proteins.

The cell-binding carboxyterminal undecapeptide of SV40 tumour antigen provides protective cell-dependent immunity.

This paper describes the use of the synthetic carboxyterminal undecapeptide of large SV40 tumour antigen, lys698-thr708 (KT) to protect Balb/c mice against growth of subcutaneously transplanted tumorigenic SV40-transformed cells (VLM). The vaccine was prepared by conjugation of KT with 3-(2-pyridyldithio)propionic acid N-hydroxysuccinimide (SPDP). Addition of the SPDP-derivative of KT to syngeneic spleen cells rendered KT covalently linked to free thiol-groups of the cell membranes by the formation of -S-S-CH2-CH2-CO-epsilon-NH-lys698 bonds. Vaccination with KT-conjugated cells was intraperitoneal. Alternatively, KT-conjugated cells were generated in the peritoneum by injection of PDP-KT ((2-pyridyldithio)propionic acid-KT). As a control 60Co-irradiated VLM cells were used. In five experiments all VLM-vaccinated and the majority of the PDP-KT-(or KT-spleen cell)-vaccinated mice were protected against tumour growth. However, mice pretreated with saline, unconjugated spleen cells, free KT, KT conjugated to bovine serum albumin, or KT with incomplete Freund's adjuvant developed tumours. Treatment of PDP-KT-vaccinated mice with anti-CD4 or anti-CD8 immunoglobulin abolished tumour immunity completely. Thus, covalent binding of the carboxyterminal undecapeptide of SV40 tumour antigen to viable, untransformed cells yielded a vaccine which protects Balb/c mice against SV40 tumours.

Covalent immunochemical membrane labeling of viable cells with K698-T708, a simian virus 40 tumor antigen-derived peptide.

The process of covalent immunochemical linking of viable cell membranes with a Simian Virus 40 (SV40) tumor antigen-derived undecapeptide, K(698)PPTPPPEPET(708) (KT), is described. The principle applied was the reaction of the lysine residue, K 698, of the undecapeptide with the succinimidyl moiety of a heterobifunctional linker molecule, N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP) or sulfosuccinimidyl(4-iodo-acetyl)aminobenzoate (sulfo-SIAB). Thereby, upon release of N-hydroxy-succinimide, the rest of the linker molecule reacts covalently with the epsilon-NH2 group of lysine. Upon release of pyridyl-2-thion or hydrogen iodide, respectively, the second reactive moiety of the linker is then ready to form a covalent bond with SH-groups of cell membrane compounds. As a result, KT is covalently linked onto the cell membrane by an -SS- or an -S-bond, respectively. Binding is prevented by treatment of the candidate cells with iodoacetamide, an SH-reactive compound. This artificial cell membrane epitope can be demonstrated by surface immunofluorescence and by binding to immunomagnetic beads loaded with PAb1605, a KT-specific monoclonal antibody. Quantitation by cytofluorimetry shows some 10(4) KT molecules bound per cell, a number that is in the range of the number of SV40 tumor antigen molecules of genuine SV40-transformed mammalian cells.

Microbial growth patterns described by fractal geometry.

Fractal geometry has made important contributions to understanding the growth of inorganic systems in such processes as aggregation, cluster formation, and dendritic growth. In biology, fractal geometry was previously applied to describe, for instance, the branching system in the lung airways and the backbone structure of proteins as well as their surface irregularity. This investigation applies the fractal concept to the growth patterns of two microbial species, Streptomyces griseus and Ashbya gossypii. It is a first example showing fractal aggregates in biological systems, with a cell as the smallest aggregating unit and the colony as an aggregate. We find that the global structure of sufficiently branched mycelia can be described by a fractal dimension, D, which increases during growth up to 1.5. D is therefore a new growth parameter. Two different box-counting methods (one applied to the whole mass of the mycelium and the other applied to the surface of the system) enable us to evaluate fractal dimensions for the aggregates in this analysis in the region of D = 1.3 to 2. Comparison of both box-counting methods shows that the mycelial structure changes during growth from a mass fractal to a surface fractal.