Endogenous tissue engineering: PTH therapy for skeletal repair

Based on its proven anabolic effects on bone in osteoporosis patients, recombinant parathyroid hormone (PTH_1-34) has been evaluated as a potential therapy for skeletal repair. In animals, the effect of PTH_1-34 has been investigated in various skeletal repair models such as fractures, allografting, spinal arthrodesis and distraction osteogenesis. These studies have demonstrated that intermittent PTH_1-34 treatment enhances and accelerates the skeletal repair process via a number of mechanisms, which include effects on mesenchymal stem cells, angiogenesis, chondrogenesis, bone formation and resorption. Furthermore, PTH_1-34 has been shown to enhance bone repair in challenged animal models of aging, inflammatory arthritis and glucocorticoid-induced bone loss. This pre-clinical success has led to off-label clinical use and a number of case reports documenting PTH_1-34 treatment of delayed-unions and non-unions have been published. Although a recently completed phase 2 clinical trial of PTH_1-34 treatment of patients with radius fracture has failed to achieve its primary outcome, largely because of effective healing in the placebo group, several secondary outcomes are statistically significant, highlighting important issues concerning the appropriate patient population for PTH_1-34 therapy in skeletal repair. Here, we review our current knowledge of the effects of PTH_1-34 therapy for bone healing, enumerate several critical unresolved issues (e.g., appropriate dosing regimen and indications) and discuss the long-term potential of this drug as an adjuvant for endogenous tissue engineering.     

Corticosteroidogenesis in the hypertrophic adrenal gland produced by betamethasone 17, 21-dipropionate in the rat fetus

Betamethasone 17, 21-dipropionate (BMDP), a potent glucocorticoid, produces adrenal hypertrophy in the rat fetus. The present study was performed to investigate the possible alterations of corticosteroidogenesis due to endogeneous substrates or exogenous pregnenolone in the incubation of homogenates of fetal hypertrophic adrenals caused by BMDP given to pregnant rats at day 19 of pregnancy.The corticosteroidal products and those levels per mg homogenate in an incubate of the hypertrophic adrenal homogenate did not differ from those of a normal adrenal. No accumulations of abnormal precursors or intermediates were found in the incubates of the hypertrophic adrenals. It is concluded from these findings that no qualitative alterations in the pathway of corticosteroidogenesis occurred in the hypertrophic adrenal glands caused by BMDP in the rat fetus. When the calculation was done per adrenal gland, the content of corticosterone in the incubate of the homogenate of the hypertrophic adrenal was remarkably higher than that found in a normal gland. This finding was compatible with the significant increase of the plasma corticosterone concentration in the fetuses with the adrenal hypertrophy caused by BMDP.     

Change in the ultraviolet spectrum of solubilized Ca2+-dependent ATPase from sarcoplasmic reticulum due to binding with Ca2+ ions.

Solubilized sarcoplasmic reticulum (SSR) was prepared by solubilizing fragmented sarcoplasmic reticulum (FSR) with a nonionic detergent (C12E8) then displacing the detergent with Tween 80, using a DEAE-cellulose column. The UV absorption of SSR decreased reversibly at about 286 and 292 nm on removal of free Ca2+ ions, while no change in the fluorescence spectrum was detectable. On the other hand, the fluorescence intensity of FSR decreased 3-4% on removal of free Ca2+ ions, as previously reported by Dupont [(1976) Biochem. Biophys. Res. Commun. 71, 544-550]. The UV absorption of FSR increased reversibly at about 270-280 nm on removal of free Ca2+ ions, but the rate of the change was very slow (k = about 0.1 min-1).     

Control of the growth of Alicyclobacillus acidoterrestris in industrialized orange juice using rosemary essential oil and nisin

The use of rosemary essential oil (RO) and its combination with nisin (RO+N) in preventing the multiplication of Alicyclobacillus acidoterrestris in orange juice was evaluated. The minimum inhibitory and bactericidal concentrations (MIC and MBC) for RO were both 125 μg ml⁻¹ while RO+N displayed a synergistic effect. The use of RO and RO+N at concentrations of 1, 4 and 8× MIC in orange juice for 96 h was evaluated in terms of their sporicidal effectiveness. With regard to the action against A. acidoterrestris spores, RO at 8× MIC was sporostatic, whereas RO+N at 1× MIC was sporicidal. Morphological changes in the structure of the micro-organism after treatment were also observed by microscopy. Furthermore, flow cytometric analysis showed that most cells were damaged or killed after treatment. In general, the antioxidant activity after addition of RO+N decreased with time. The results demonstrate that using the combination of RO and nisin can prevent the A. acidoterrestris growth in orange juice.     

Sequences of cDNAs for human salivary and pancreatic α-amylases

The nucleotide sequences of the cloned human salivary and pancreatic α-amylase cDNAs correspond to the continuous mRNA sequences of 1768 and 1566 nucleotides, respectively. These include all of the amino acid coding regions. Salivary cDNA contains 200 bp in the 5′-noncoding region and 32 in the 3′-noncoding region. Pancreatic cDNA contains 3 and 27 bp of 5′- and 3′-noncoding regions, respectively. The nucleotide sequence humology of the two cDNAs is 96% in the coding region, and the predicted amino acid sequences are 94% homologous.Comparison of the sequences of human α-amylase cDNAs with those previously obtained for mouse α-amylase genes (Hagenbuchle et al., 1980; Schibler et al., 1982) showed the possibility of gene conversion between the two genes of human α-amylase.     

Degradation of aromatic amino acids by Rhodococcus erythropolis

A Gram-positive Rhodococcus erythropolis strain S1 was shown to assimilate aromatic amino acids such as L-phenylalanine, L-tyrosine, L-tryptophan, D-phenylalanine, D-tyrosine and D-tryptophan, which were utilized not only as the sole carbon source but also as a suitable nitrogen source. The highest growth on these aromatic amino acids occurred at a temperature of 30°C. L-Phenylalanine, L-tyrosine and L-tryptophan degradative pathways would appear to be independent, and to be induced alternatively. The strain S1 also showed the ability to assimilate peptides which consisted of only L-phenylalanine and L-tyrosine.     

Application of a new slot comb to electrophoretic analysis.

In the present experiment, a new slot comb was designed in order to form a wide and sloped sample well on the stacking gel of electrophoresis. Using this slot comb, a gradient of the reagent layer of interest can be easily formed transversely on the gel that is perpendicular to the direction of electrophoresis. Thus, the protein sample overlaid on the agent migrates across the gradient layer during electrophoresis to produce a continuous electrophoretic band reflecting the interaction between the protein and reagent. This new slot comb (tentatively called slope comb) was applied to the following two experiments. In the first experiment, in combination with this comb and a reducing agent, 2-mercaptoethanol, the reducing steps of cross-linked axonemal proteins with o-iodosobenzoic acid (OIBA) were analyzed electrophoretically, enabling visualization of the reducing pattern of each axonemal protein in a single experiment. The results obtained indicate that alpha and beta tubulins are cross-linked differently by OIBA. In the second experiment, the formation of the Ca2+ gradient layer using this slope comb could electrophoretically differentiate the Ca2+ sensitivity of three Ca(2+)-binding proteins.     

Gelation mechanism of agarose

The non-Newtonian behavior and dynamic viscoelasticity of a series of aqueous solutions of agarose were measured with a rheogoniometer. The flow curve, at 25°, of agarose solution approximated to plastic behavior at 0.1, 0.13, and 0.15% concentrations. Gelation occurred at concentration of 0.13% at low temperature (0°). The dynamic modulus of agarose showed a very high value at low temperature, and increased with an increase in temperature, showing a maximum value at 30°, then it decreased. In the presence of NaCl, KCl, CaCl₂, and MgCl₂ for a solution of agarose at 0.08% concentration, the transition temperature, at which dynamic modulus decreased rapidly, was observed at 60°. Gelation was also observed at low temperature (0°) in acid and alkaline range after reaching pH values of 2.3 and 9.5, respectively, by addition of 100m HCl, H₂SO₄, NaOH, and Ca(OH)₂ to a 0.08% agarose solution. A possible mode of intra- and inter-molecular hydrogen bonding within and between the agarose molecules in aqueous solution is proposed.     

Role of virus inhibitory factor or interferon in the antitumoral effect of whole-body hyperthermia

The interferon inducing effect of hyperthermia was studied in normal and tumor-bearing mice. Circulating interferon was temporarily detected one day after subcutaneous transplantation of 1.6 X 10(6) Ehrlich's ascites tumor cells. Hyperthermia of 43.5 degrees C for 5 min did not induce the interferon formation in mice with or without subcutaneous tumor of the cells. These findings showed that the induction of interferon formation was not main cause of the hyperthermia-induced tumor inhibition.