Effects of transforming growth factor beta1 on bonelike tissue formation in three-dimensional cell culture. I. Culture conditions and tissue formation

Bone tissue engineering based on growing bone marrow stromal cells on poly(L-lactic-co-glycolic acid) fiber meshes suffers from limited matrix production and mineralization when the cells are cultured with the standard differentiation supplements (dexamethasone, beta-glycerophosphate, and ascorbic acid). To overcome this problem we included transforming growth factor beta1 (TGF-beta1), which is described as playing a key role in collagen type I formation, although its effect on mineralization is controversially discussed. The investigations focused on establishing culture conditions for the application of TGF-beta1 in three-dimensional cell culture and on the effects of different doses of TGF-beta1 (1-20 ng/mL) on bonelike extracellular matrix formation. Immunohistochemical staining showed that TGF-beta1 enhanced the formation of procollagen type I, collagen type I, and collagen type V, especially under dynamic culture conditions (orbital shaker). A long-term study confirmed positive effects on the formation of extracellular matrix, which penetrated the scaffold to a depth of 250 to 300 microm. Mineralization, qualified by scanning electron microscopy in combination with energy-dispersive X-ray analysis and evaluated by determination of the Ca2+ content per scaffold, was up to 1.7-fold increased by TGF-beta1 compared with the control. In conclusion, the growth factor TGF-beta1 seems to be effective in improving extracellular bonelike matrix formation in vitro.     

Delta9-tetrahydrocannabinol increases C6 glioma cell death produced by oxidative stress

(-)Delta9-tetrahydrocannabinol is a scavenger of free radicals. However, the activation of the CB1 receptor in cultured C6 glioma cells by (-)delta9-tetrahydrocannabinol in the presence of reagents generating reactive oxygen species leads to amplification of the cellular damage from oxidative stress. This was evident by increased loss of cell wall integrity, impaired mitochondrial function and reduction of glucose uptake. In addition, (-)delta9-tetrahydrocannabinol treatment was also found to be deleterious to the cells under conditions of glucose starvation. Free radicals have been implicated in various conditions leading to cell death and, as a routine, the Fenton reaction is utilized for modeling reactive oxygen species production. Our study was performed using a cell permeating Fe(III) chelating quinone that provides more physiological conditions for mimicking the naturally occurring oxidative stress within the cell and thus serves as a better model for natural reactive oxygen species formation.     

Mimotope and anti-idiotypic vaccines to induce an anti-IgE response

We have defined epitopes on human IgE by screening different phage display random peptide libraries with a monoclonal anti-IgE antibody termed BSW17. The selected mimotopes and epitopes within the Cepsilon3 and Cepsilon4 region of IgE induced antibodies that were nonanaphylactogenic and had biological activity similar to BSW17. The chemically synthesized and KLH-coupled IgE epitopes or mimotopes were used to induce an anti-IgE response in rhesus monkeys. The immunized rhesus monkeys were subsequently protected in a PCA test when sensitized with human IgE and triggered with the corresponding allergen. Furthermore, using the same monoclonal anti-IgE antibody, we also generated an anti-idiotypic antibody that showed sequence homology with the IgE epitope in the Cepsilon3 domain. This anti-idiotypic antibody as well as the mimotopes were then used in a mouse model to induce orally an anti-IgE immune response. For this purpose mice were fed by intragastric gavages with bacteriophages displaying the small IgE-homologous structures. Orally immunized mice produced serum anti-IgE antibodies that were inhibited by BSW17 suggesting that it may be possible to induce a systemic anti-IgE response orally.     

A case with 46, XX, del (11) (q21)

The cytogenetic analysis of a child with unspecific dysplastic signs revealed the karyotype: 46, XX, del(11) (q21). Two hypotheses could explain the mild phenotypical expression of this deletion:
1) The material of the deficient part of chromosome 11 is genetically inert or redundant (which seems unlikely);
2) "Gene-dosis-compensation" occurs for the loss of genes on the deficient part of chromosome 11.     

Modifizierung von homo- und copolymeren des epichlorhydrins durch polymeranaloge umsetzungen

Poly(epichlorohydrin) and poly(epichlorohydrin-co-ethylene oxide) were modified by reaction with potassium thiocyanate (KSCN), tetrabutylammonium p-toluenesulfinate (NBu₄SO₂C₇H₇) and tetrabutylammonium benzenesulfinate (NBu₄SO₂C₆H₅). Though the substitution of chlorine in the polymers with these nucleophilic reagents in most cases is accompanied by side reactions, appropriate reaction conditions allow degrees of substitution higher than 90% to be obtained. The glass transition temperature (T_g) of the thiocyanate-modified homo- and copolymer exhibits only a small increase with increasing degree of substitution. While the T_g of the original homo- and copolymer is observed at ?20°C and ?38°C, respectively, the glass transition of the highly substituted homopolymer occurs at ?12°C and for the copolymer at ?31°C. On the other hand, the thiocyanate-modified polymers show a remarkably higher decomposition temperature of about 250°C as compared with that of the unmodified polymers (160–180°C). In addition, the solubility is markedly influenced by the substitution. While the original homo- and copolymers are soluble in, e.g., benzene and toluene, the highly modified products are only soluble in polar solvents such as THF, acetone, DMSO and diglyme. Introducing sulfonyl groups, the resulting polymers exhibit a glass transition temperature increased to a greater extent. For the homopolymer with the highest degree of substitution (98,3%), a T_g of 73°C is observed. Concerning the decomposition temperature, a drastical increase up to 370°C occurs. Finally the influence of phase transfer catalysts on the described reactions was investigated.     

Description of a hybridoma bank towards Bordetella pertussis toxin and surface antigens

This paper describes the development of a murine bank of monoclonal antibodies against Bordetella pertussis toxin, filamentous hemagglutinin (FHA), pili, lipopolysaccharide (LPS), or outer membrane proteins (OMPs). Subunits S1, S2, S3 of pertussis toxin (PT) bound immunoglobulins and glycoproteins such as fetuin and haptoglobin in an unspecific manner. The specificity of monoclonal antibodies towards subunits S1, S2, S3 or S4 of PT could be demonstrated by using purified immunoglobulins or their Fab2 fragments. A set of FHA-specific monoclonal antibodies could be differentiated on the basis of their binding to the various breakdown products present in FHA preparations. Pili-specific monoclonal antibodies reacted with either native pili or denatured pilin, and both demonstrated serotype specificity. Monoclonal antibodies to Bordetella pertussis OMPs were directed to either the virulent phase-regulated trypsin-sensitive, detergent-extractable OMPs 92 kDa, 32 kDa, and 30 kDa or the non-virulent phase-expressed, not-trypsin sensitive OMPs 38 kDa, 33kDa, and 18 kDa.     

"Effort" thrombosis of the subclavian vein in a competitive swimmer

"Effort" thrombosis is a unique form of subclavian and axillary vein thrombosis because it is the result of an unusual variant of the thoracic outlet syndrome. Another cause of subclavian vein thrombosis is local compression from trauma, tumor, or development anomalies; a third is intimal damage from indwelling central venous catheters. This is a case report of "effort" thrombosis of the subclavian vein in a competitive swimmer. A recently developed technique of local infusion of low-dose streptokinase therapy is used for clot lysis. Early diagnosis is essential for effective thrombus dissolution with streptokinase. The rationale, risk, and method of streptokinase administration are discussed. Since "effort" thrombosis is secondary to thoracic outlet syndrome (TOS), decompression of the thoracic outlet by removal of the first rib after clot lysis is recommended.