Pathophysiology of Tumor Neovascularization

Neovascularization is essential to the process of development and differentiation of tissues in the vertebrate embryo, and is also involved in a wide variety of physiological and pathological conditions in adults, including wound repair, metabolic diseases, inflammation, cardiovascular disorders, and tumor progression. Thanks to cumulative studies on vasculature, new therapeutic approaches have been opened for us to some life-threatening diseases by controlling angiogenesis in the affected organs. In cancer therapy, for example, modulation of factors responsible for tumor angiogenesis may be beneficial in inhibiting of tumor progression. Several antiangiogenic approaches are currently under preclinical trial. However, the mechanisms of neovascularization in tumors are complicated and each tumor shows unique features in its vasculature, depending on tissue specificity, angiogenic micromilieu, grades and stages, host immunity, and so on. For better understanding and effective therapeutic approaches, it is important to clarify both the general mechanism of angiogenic events and the disease-specific mechanism of neovascularization. This review discusses the general features of angiogenesis under physiological and pathological conditions, mainly in tumor progression. In addition, recent topics such as contribution of the endothelial progenitor cells, tumor vasculogenic mimicry, markers for tumor-derived endothelial cells and pericytes, and angiogenic/angiostatic chemokines are summarized

Clinical Study on Slight Fever

Between May 1981 and April 1986, 1402 patients were admitted to the Department of Primary Care Medicine of Kawasaki Medical School Hospital. Of these, 452 patients had a slight fever ranging from 37.0°C to 37.9°C. We analyzed those patients clinically. Infection ranked first as the cause of slight fever, followed by malignancy, collagen disease and others. About 50% of the cases were of unknown origin, and many cases with CRP and ESR almost within the normal range convalesced satisfactorily. The measurement of CRP and ESR in slight fever patients were useful to exclude organic slight fever. The cases with a slight fever of unknown origin appearing for a long term also often had nonorganic diseases such as depression or neurosis. Almost all of these cases were placed in the category of habitual hyperthermia

Effectiveness of Fluconazole for Pulmonary Aspergilloma and Its Concentration in Lung Tissue

Fluconazole was administered to two male patients aged 41 and 70 years with pulmonary aspergilloma, the diagnosis of which was based on "fungus balls" on chest X-ray films, isolation of Aspergillus from the sputum and positive serum precipitation antibody against Aspergillus. The patients received a 100 to 200 mg oral daily dose of fluconazole for six months. The fungus balls shrank and disappeared and Aspergillus culture and the serum antibody became negative. No recurrence has been observed during the two years since the end of treatment. To determine the mechanism by which fluconazole was effective in the treatment of pulmonary aspergilloma, drug levels in the blood and normal and affected lung tissues were determined in 14 patients who received surgery for lung resection. The patients generally received a 200 mg oral daily dose of fluconazole for four days prior to the surgery, during which samples of blood and healthy and affected lung tissues were collected for the determination of fluconazole levels by HPLC. The average fluconazole concentration was 8.2 μ/ml in the blood (14 patients), 9.4 μg/g in healthy lung tissue (10 patients) and 7.7 μg/g in lung lesions (12 patients). Although the results suggested that the drug was well distributed into the blood and lung tissue when administered at an oral dose of 200 mg, the drug levels obtained were found to be far below the growth inhibitory level of fluconazole against Aspergillus. Therefore, it may be essential for the future development of antifungal agents and for a better understanding of the pharmacological action of fluconazole to evaluate the mechanism by which the drug exerts its therapeutic effect on aspergilloma at below its growth inhibitory level

Piezo1-pannexin-1-P2X3 axis in odontoblasts and neurons mediates sensory transduction in dentinal sensitivity

According to the “hydrodynamic theory,” dentinal pain or sensitivity is caused by dentinal fluid movement following the application of various stimuli to the dentin surface. Recent convergent evidence in Vitro has shown that plasma membrane deformation, mimicking dentinal fluid movement, activates mechanosensitive transient receptor potential (TRP)/Piezo channels in odontoblasts, with the Ca2+ signal eliciting the release of ATP from pannexin-1 (PANX-1). The released ATP activates the P2X3 receptor, which generates and propagates action potentials in the intradental Aδ afferent neurons. Thus, odontoblasts act as sensory receptor cells, and odontoblast-neuron signal communication established by the TRP/Piezo channel-PANX-1-P2X3 receptor complex may describe the mechanism of the sensory transduction sequence for dentinal sensitivity. To determine whether odontoblast-neuron communication and odontoblasts acting as sensory receptors are essential for generating dentinal pain, we evaluated nociceptive scores by analyzing behaviors evoked by dentinal sensitivity in conscious Wistar rats and Cre-mediated transgenic mouse models. In the dentin-exposed group, treatment with a bonding agent on the dentin surface, as well as systemic administration of A-317491 (P2X3 receptor antagonist), mefloquine and 10PANX (non-selective and selective PANX-1 antagonists), GsMTx-4 (selective Piezo1 channel antagonist), and HC-030031 (selective TRPA1 channel antagonist), but not HC-070 (selective TRPC5 channel antagonist), significantly reduced nociceptive scores following cold water (0.1 ml) stimulation of the exposed dentin surface of the incisors compared to the scores of rats without local or systemic treatment. When we applied cold water stimulation to the exposed dentin surface of the lower first molar, nociceptive scores in the rats with systemic administration of A-317491, 10PANX, and GsMTx-4 were significantly reduced compared to those in the rats without systemic treatment. Dentin-exposed mice, with somatic odontoblast-specific depletion, also showed significant reduction in the nociceptive scores compared to those of Cre-mediated transgenic mice, which did not show any type of cell deletion, including odontoblasts. In the odontoblast-eliminated mice, P2X3 receptor-positive A-neurons were morphologically intact. These results indicate that neurotransmission between odontoblasts and neurons mediated by the Piezo1/TRPA1-pannexin-1-P2X3 receptor axis is necessary for the development of dentinal pain. In addition, odontoblasts are necessary for sensory transduction to generate dentinal sensitivity as mechanosensory receptor cells

Mechanical Stimulation-Induced Calcium Signaling by Piezo1 Channel Activation in Human Odontoblast Reduces Dentin Mineralization

Odontoblasts play critical roles in dentin formation and sensory transduction following stimuli on the dentin surface. Exogenous stimuli to the dentin surface elicit dentinal sensitivity through the movement of fluids in dentinal tubules, resulting in cellular deformation. Recently, Piezo1 channels have been implicated in mechanosensitive processes, as well as Ca(2+) signals in odontoblasts. However, in human odontoblasts, the cellular responses induced by mechanical stimulation, Piezo1 channel expression, and its pharmacological properties remain unclear. In the present study, we examined functional expression of the Piezo1 channel by recording direct mechanical stimulation-induced Ca(2+) signaling in dentin matrix protein 1 (DMP-1)-, nestin-, and dentin sialophosphoprotein (DSPP)-immunopositive human odontoblasts. Mechanical stimulation of human odontoblasts transiently increased intracellular free calcium concentration ([Ca(2+)](i)). Application of repeated mechanical stimulation to human odontoblasts resulted in repeated transient [Ca(2+)](i) increases, but did not show any desensitizing effects on [Ca(2+)](i) increases. We also observed a transient [Ca(2+)](i) increase in the neighboring odontoblasts to the stimulated cells during mechanical stimulation, showing a decrease in [Ca(2+)](i) with an increasing distance from the mechanically stimulated cells. Application of Yoda1 transiently increased [Ca(2+)](i). This increase was inhibited by application of Gd(3+) and Dooku1, respectively. Mechanical stimulation-induced [Ca(2+)](i) increase was also inhibited by application of Gd(3+) or Dooku1. When Piezo1 channels in human odontoblasts were knocked down by gene silencing with short hairpin RNA (shRNA), mechanical stimulation-induced [Ca(2+)](i) responses were almost completely abolished. Piezo1 channel knockdown attenuated the number of Piezo1-immunopositive cells in the immunofluorescence analysis, while no effects were observed in Piezo2-immunopositive cells. Alizarin red staining distinctly showed that pharmacological activation of Piezo1 channels by Yoda1 significantly suppressed mineralization, and shRNA-mediated knockdown of Piezo1 also significantly enhanced mineralization. These results suggest that mechanical stimulation predominantly activates intracellular Ca(2+) signaling via Piezo1 channel opening, rather than Piezo2 channels, and the Ca(2+) signal establishes intercellular odontoblast-odontoblast communication. In addition, Piezo1 channel activation participates in the reduction of dentinogenesis. Thus, the intracellular Ca(2+) signaling pathway mediated by Piezo1 channels could contribute to cellular function in human odontoblasts in two ways: (1) generating dentinal sensitivity and (2) suppressing physiological/reactional dentinogenesis, following cellular deformation induced by hydrodynamic forces inside dentinal tubules