Evaluation of Cholecystokinin (CCK-8) Peptide Thermal Stability for Use as Radiopharmaceutical by Means Isothermal and Nonisothermal Approaches

The purpose of this research was to study the thermal stability of cholecystokinin octapeptide (CCK-8) in aqueous solution at pH 12 and ionic strength 0.01 M, which were kept as constants, by using isothermal and nonisothermal methods. The isothermal decomposition of CCK-8 was investigated as a function of temperature (40 degrees C to 70 degrees C). Nonisothermal stability studies were performed using a linear increasing temperature program. Two different nonisothermal studies were carried out at 0.25 degrees K and 0.5 degrees K per hour, and the temperature interval varied from 40 degrees C to 82 degrees C. The degradation of CCK-8 followed first-order kinetics, obeying the Arrhenius equation in the experimental temperature range. This indicated that the degradation mechanism of CCK-8 could be the equal within the temperature range studied. The nonisothermal approach resulted in activation energy (Ea) and shelf-life (t90%) values that agree well with those obtained by the isothermal method. The level of uncertainty in the estimates of t90% and Ea values is determined mainly by the extent of drug degradation and temperature change during the experiment. Therefore, nonisothermal experiments save time, labor and materials (i.e. the amount of drugs necessary to conduct the experiment) compared to the classic isothermal experiments, if they are performed using a suitable experimental design and a precise analytical method.

[Environmental pollutants and prostate cancer: epidemiological data]

Prostate cancer is the most frequent cancer affecting men in most Western countries. Certain risk factors have been identified (age, family history, ethnic origin), but the aetiology of this cancer remains largely unknown. However, a role for environmental factors is strongly suspected. Questions have been raised concerning the role of the chemical substances generated by human activities in the occurrence of this disease. Diverse studies have consistently demonstrated a higher risk of prostate cancer in agricultural populations than in the general population. The hypothesis that this higher risk is linked to the use of pesticides has been tested in a number of studies, mostly in North America and Europe. However, to date, with a few possible exceptions, it has been impossible to demonstrate a significant association between exposure to pesticides or a chemical family of pesticides and prostate cancer. Studies have also been carried out on the role of exposure to trace metals, such as cadmium, or to pollutants from industry, such as polychlorobiphenyls. However, no firm conclusions have been drawn. Finally, the effect of chemical substances with endocrine disruptor activity on the occurrence of prostate cancer remains largely unexplored in epidemiological studies. In the face of these uncertainties, rigorous studies are required, with objective measurements of exposure, taking into account confounding factors and individual risk factors, making it possible to assess gene-environment interactions.

Improving women's health through modernization of our bioinformatics infrastructure

Our nationwide bioinformatics infrastructure used to detect important sex differences associated with medical product use is antiquated. The Food and Drug Administration (FDA) has embarked on an ambitious bioinformatics modernization effort that will improve our ability to assess the safety and effectiveness of new medical products. This, in turn, will improve our ability to detect important sex differences.

Identification, characterization and manipulation of Babesia-bovis-infected red blood cells using microfluidics technology

Nowadays numerous microfluidic systems are being developed to address a variety of clinical problems. Latest advances in microfluidic technology are promising to revolutionize the detection of pathogens in vivo through the development of integrated lab-on-chip devices. Such microfabricated systems will undertake all steps in sample analysis from collection and preparation to molecular detection. Micro total analysis systems are suitable candidates for point of care diagnostics due to small size, low cost production and enabled portability. The work here presented aimed the use of microfluidic platforms to identify and manipulate bovine red blood cells infected by the protozoan parasite Babesia bovis. A microfabricated device based on impedance spectroscopy was used for single cell discrimination and its sensitivity and applicability as a diagnostic method for bovine babesiosis was studied. Furthermore, manipulation and sorting of normal and infected red blood cells was performed on a dielectrophoresis based microfabricated cell cytometer. Single cell analysis of normal and B. bovis infected red blood cells was performed by electrorotation and dielectric parameters such as permittivities and conductivities of the cellular membrane and cytoplasm were determined.

Effects of Emdogain on osteoblast gene expression

OBJECTIVE

Emdogain (EMD) is a protein extract purified from porcine enamel and has been introduced in clinical practice to obtain periodontal regeneration. EMD is composed mainly of amelogenins (90%), while the remaining 10% is composed of non-amelogenin enamel matrix proteins such as enamelins, tuftelin, amelin and ameloblastin. Enamel matrix proteins seem to be involved in root formation. EMD has been reported to promote proliferation, migration, adhesion and differentiation of cells associated with healing periodontal tissues in vivo.

DESIGN

How this protein acts on osteoblasts is poorly understood. We therefore attempted to address this question by using a microarray technique to identify genes that are differently regulated in osteoblasts exposed to enamel matrix proteins.

RESULTS

By using DNA microarrays containing 20,000 genes, we identified several upregulated and downregulated genes in the osteoblast-like cell line (MG-63) cultured with enamel matrix proteins (Emd). The differentially expressed genes cover a broad range of functional activities: (i) signaling transduction, (ii) transcription, (iii) translation, (iv) cell cycle regulation, proliferation and apoptosis, (v) immune system, (vi) vesicular transport and lysosome activity, and (vii) cytoskeleton, cell adhesion and extracellular matrix production.

CONCLUSIONS

The data reported are the first genome-wide scan of the effect of enamel matrix proteins on osteoblast-like cells. These results can contribute to our understanding of the molecular mechanisms of bone regeneration and as a model for comparing other materials with similar clinical effects.

Development of a recombinant indirect ELISA for the diagnosis of Theileria sp. (China) infection in small ruminants

Theileria sp. (China) causes severe limitations on the development of the livestock industry in the north-west of China. An enzyme-linked immunosorbent assay (ELISA) based on merozoite homogenate of the parasite for diagnosis of infection has been established; however, cross-reactivity with other small ruminant-infecting piroplasms could not be excluded. Thus, a prerequisite for epidemiological surveys and diagnosis was the establishment of a recombinant protein-based ELISA. To this end, serum from Theileria sp. (China)-infected sheep was used to screen a Theileria lestoquardi expression library, resulting in the identification of a specifically reacting clone with a high identity to the heat shock protein 70 (HSP70) of Theileria parva and Theileria annulata and thus named TlHSP70. An HSP70 homologue was also confirmed to be expressed by Theileria sp. (China) merozoites (TcHSP70). A part of the TlHSP70 protein, found to be conserved in TcHSP70, was recombinantly expressed and used to establish an ELISA. A total of 260 field serum samples tested resulted in a sensitivity and specificity of 94.3 and 89.5%, respectively, in comparison with the merozoite homogenate ELISA. The potentials of the application of the test in epidemiological surveys to map out the prevalence of the disease and for routine diagnostics are described.

A mathematical model for interpreting in vitro rhGH release from laminar implants

Recombinant human growth hormone (rhGH), used mainly for the treatment of growth hormone deficiency in children, requires daily subcutaneous injections. The use of controlled release formulations with appropriate rhGH release kinetics reduces the frequency of medication, improving patient compliance and quality of life. Biodegradable implants are a valid alternative, offering the feasibility of a regular release rate after administering a single dose, though it exists the slight disadvantage of a very minor surgical operation. Three laminar implant formulations (F(1), F(2) and F(3)) were produced by different manufacture procedures using solvent-casting techniques with the same copoly(D,L-lactic) glycolic acid (PLGA) polymer (Mw=48 kDa). A correlation in vitro between polymer matrix degradation and drug release rate from these formulations was found and a mathematical model was developed to interpret this. This model was applied to each formulation. The obtained results where explained in terms of manufacture parameters with the aim of elucidate whether drug release only occurs by diffusion or erosion, or by a combination of both mechanisms. Controlling the manufacture method and the resultant changes in polymer structure facilitates a suitable rhGH release profile for different rhGH deficiency treatments.

Amplification of spatial dispersion of repolarization underlies sudden cardiac death associated with catecholaminergic polymorphic VT, long QT, short QT and Brugada syndromes

This review examines the hypothesis that amplification of spatial dispersion of repolarization in the form of transmural dispersion of repolarization (TDR) underlies the development of life-threatening ventricular arrhythmias associated with inherited ion channelopathies including the long QT, short QT and Brugada syndromes as well as catecholaminergic polymorphic ventricular tachycardia. In the long QT syndrome, amplification of TDR is often secondary to preferential prolongation of the action potential duration (APD) of M cells, whereas in the Brugada syndrome, it is thought to be because of selective abbreviation of the APD of right ventricular epicardium. Preferential abbreviation of APD of either endocardium or epicardium appears to be responsible for amplification of TDR in the short QT syndrome. In catecholaminergic polymorphic VT, the reversal of the direction of activation of the ventricular wall is responsible for the increase in TDR. In conclusion, the long QT, short QT, Brugada and catecholaminergic VT syndromes are pathologies with very different phenotypes and aetiologies, but which share a common final pathway in causing sudden death.

In vitrocell-type specific biological response of human periodontally related cells to platelet-rich plasma

OBJECTIVES

Platelet-rich plasma is a blood-derived fraction containing high concentrations of platelets and growth factors. Applied in the form of a gel on surgical wounds, it is able to stimulate hard and soft tissue repair and has been proposed for use in the field of periodontal regeneration. However to date, little is known about the biological interactions between platelet-rich plasma and periodontally related cells. In this study, we investigated the effects between platelet-rich plasma and cell populations involved in periodontal regeneration, namely primary human periodontal ligament cells, gingival fibroblasts and keratinocytes.

MATERIAL AND METHODS

The proliferation of human periodontal ligament cells, gingival fibroblasts and keratinocytes by [3H]thymidine incorporation was assessed. The alkaline phosphatase activity and type I collagen levels of human periodontal ligament cells were also evaluated by a spectrophotometric assay and western blot analysis, respectively.

RESULTS

Incubation of human periodontal ligament cells with platelet-rich plasma resulted in time-dependent growth stimulation (up to fourfold of control at 72 h). Likewise, an increase in the specific activity of alkaline phosphatase (fourfold at 6 days) and collagen (twofold at 7 days) was observed. Platelet-rich plasma also enhanced human gingival fibroblasts proliferation by twofold, whereas it inhibited human keratinocytes growth by 40%, with respect to their own controls at 72 h.

CONCLUSION

Cell populations related to periodontal tissue were differently affected by platelet-rich plasma. In fact, a strong stimulation of human periodontal ligament cells proliferation, a minor increase in the growth rate of human gingival fibroblasts and a marked decrease of human keratinocytes proliferation were evident. In addition, in human periodontal ligament cells increased collagen and alkaline phosphatase activity levels were observed. These findings appear interesting in view of platelet-rich plasma utilization in periodontal regeneration.

Ex vivo expansion of bone marrow stromal cells by platelet-rich plasma: a promising strategy in maxillo-facial surgery

The aim of our study is to evaluate in vitro the response of bone marrow stromal cells (BMSCs) to platelet-rich plasma (PRP), in order to clarify the potential role of their combined use in a preclinical phase preceding BMSCs transplantation for bone repair and regeneration procedures. The incubation of BMSCs with PRP promoted a remarkable, dose- and time- dependent, growth stimulation, that was paralleled to a strong increase in the quantity of type I collagen and to a significant decrease in the activity of the early osteoblastic differentiation marker, alkaline phosphatase (AP). Once PRP was removed and osteogenic inducers were added, AP returned to levels comparable to the control, while the late phenotypic markers, osteocalcin and matrix calcification, were enhanced to higher levels than in controls. Our data demonstrate that PRP induces a remarkable ex vivo enrichment of BMSCs maintaining their differentiative potential. Thus PRP represents a valid preclinical tool for obtaining an effective, rapid and safe ex vivo expansion of BMSCs prior to their clinical utilization in bone engineering.

CD1d expression by hepatocytes is a main restriction element for intrahepatic T-cell recognition

The liver has specific mechanisms to protect itself from infectious agents and to avoid autoimmunity, indicating an important role of the hepatic tissues in antigen presentation and tolerance induction. Since intrahepatic lymphocytes may contribute to the innate immunity and to the liver pathology, it is of interest to analyze the expression of antigen presenting molecules and of the related T cell recognition in liver, and how these change in relation to different diseases. We analyzed the expression of MHC class I, and of CD1-a, -b, -c, and -d proteins on liver tissues from patients with different hepatic diseases. Moreover, in the same patients we studied the intrahepatic and peripheral NKT cell recognition of alpha-galactosyl ceramide antigen in the context of CD1d. Unlike in other tissues, classical MHC class I molecules were poorly expressed in the hepatic compartment, suggesting that inflamed hepatocytes may trigger weak MHC-restricted T cell responses. Nevertheless, we observed a prevalent expression of HLA class I-like CD1d isoform on the hepatocyte surface, indicating that CD1d is the main restriction element in the liver. In patients with viral hepatitis, the intrahepatic CD1d expression parallels the recruitment of CD56+Valpha24Vbeta11+ NKT cells in the liver which recognize CD1d presenting glycolipids such as alpha-galactosyl ceramide, suggesting that the intrahepatic T cell immunity may focus on glycolipid antigens.