Photoacoustic imaging and temperature measurement for photothermal cancer therapy

Photothermal therapy is a noninvasive, targeted, laser-based technique for cancer treatment. During photothermal therapy, light energy is converted to heat by tumor-specific photoabsorbers. The corresponding temperature rise causes localized cancer destruction. For effective treatment, however, the presence of photoabsorbers in the tumor must be ascertained before therapy and thermal imaging must be performed during therapy. This study investigates the feasibility of guiding photothermal therapy by using photoacoustic imaging to detect photoabsorbers and to monitor temperature elevation. Photothermal therapy is carried out by utilizing a continuous wave laser and metal nanocomposites broadly absorbing in the near-infrared optical range. A linear array-based ultrasound imaging system is interfaced with a nanosecond pulsed laser to image tissue-mimicking phantoms and ex-vivo animal tissue before and during photothermal therapy. Before commencing therapy, photoacoustic imaging identifies the presence and spatial location of nanoparticles. Thermal maps are computed by monitoring temperature-induced changes in the photoacoustic signal during the therapeutic procedure and are compared with temperature estimates obtained from ultrasound imaging. The results of our study suggest that photoacoustic imaging, augmented by ultrasound imaging, is a viable candidate to guide photoabsorber-enhanced photothermal therapy.     

患乙型肝炎或丙型肝炎的孕妇和新生儿的护理

介绍美国对于患有乙型肝炎或丙型肝炎孕妇和新生儿的护理情况。     

Thermal intravascular photoacoustic imaging

Intravascular photoacoustics (IVPA)-a minimally invasive imaging technique with contrast related to optical absorption properties of tissue, can be used to visualize atherosclerotic plaques. However, the amplitude of photoacoustic signals is also related to a temperature dependent, tissue specific parameter-the Grüneisen parameter. Therefore, photoacoustic signals measured at different temperatures may reveal information about tissue composition. In this study, thermal IVPA (tIVPA) imaging was introduced. The imaging studies were performed using an ex vivo atherosclerotic rabbit aorta. Temperature dependent photoacoustic responses from lipid in plaques and lipid in periadventitial tissue were different, thus allowing tIVPA images to delineate the location of lipid-rich plaques. The results indicate that tIVPA imaging has a potential to characterize tissue composition in atherosclerotic vessels.     

In vivo three-dimensional spectroscopic photoacoustic imaging for monitoring nanoparticle delivery

In vivo monitoring of nanoparticle delivery is essential to better understand cellular and molecular interactions of nanoparticles with tissue and to better plan nanoparticle-mediated therapies. We developed a three-dimensional ultrasound and photoacoustic (PA) imaging system and a spectroscopic PA imaging algorithm to identify and quantify the presence of nanoparticles and other tissue constituents. Using the developed system and approach, three-dimensional in vivo imaging of a mouse with tumor was performed before and after intravenous injection of gold nanorods. The developed spectroscopic PA imaging algorithm estimated distribution of nanoparticle as well as oxygen saturation of blood. Moreover, silver staining of excised tumor tissue confirmed nanoparticle deposition, and showed good correlation with spectroscopic PA images. The results of our study suggest that three-dimensional ultrasound-guided spectroscopic PA imaging can monitor nanoparticle delivery in vivo.     

Calcitonin gene-related peptide (CGRP) may award relative protection from interferon-γ-induced collapse of human hair follicle immune privilege

Interferon-γ (IFNγ)-induced collapse of hair follicle (HF) immune privilege (IP) is a key element in the pathogenesis of alopecia areata. In this pilot study, we investigated whether the immunosuppressive neuropeptide, calcitonin gene-related peptide (CGRP), can protect from and/or restore IFNγ-induced HF-IP collapse. After showing that human scalp HFs express CGRP receptor-like receptor (CRLR) immunoreactivity, anagen HFs were cultured in the presence of IFNγ, with CGRP added before or after. Adding CGRP after IFNγ administration ('restoration assay') failed to downregulate IFNγ-induced ectopic MHC class I expression, while MHC class II expression was reduced. However, administering CGRP before IFNγ application ('protection assay') significantly reduced the IFNγ-induced overexpression and ectopic expression of MHC class I and II and reduced the increased degranulation of perifollicular mast cells induced by IFNγ. This suggests that CGRP may not restore HF-IP once it has collapsed, but may protect it from collapsing. Therefore, CRLR stimulation might help to retard AA progression.     

Normality of ambulatory blood pressure.

An operational threshold for making clinical decision on the basis of ambulatory blood pressure monitoring must be defined. This requires that the relationship between the ambulatory pressure and the incidence of cardiovascular complications be clarified beyond present understanding. Preliminary cut-off points for ambulatory monitoring were derived by averaging the 95th percentiles of the ambulatory blood pressure measurements for the normotensive subjects enrolled in various large-scale studies. According to this approach, the upper limits of normotension, calculated by rounding downwards, would be 130/80mmHg for the 24h blood pressure and 135/85 and 120/70mmHg for the daytime and night-time blood pressures. Abnormality, obtained by rounding upwards, would be blood pressure levels exceeding 135/85, 140/90 and 125/75mmHg, respectively.     

Conventional and ambulatory measurements of blood pressure in old patients with isolated systolic hypertension: baseline observations in the Syst-Eur trial

OBJECTIVES: To compare clinic and am measurements of blood pressure in old patients with isolated systolic hypertension and their reproducibilities. PATIENTS: In total 610 patients aged >/= 60 years with isolated systolic hypertension detected by clinic measurement were monitored during the placebo run-in phase of the Syst-Eur trial. METHODS: The time-weighted 24 h blood pressure, clock-time day and night blood pressures, the cumulative-sum-derived crest and trough blood pressures and the high and low blood pressure levels according to the square-wave model were computed. The daily alteration between the high and low spans of blood pressure was quantified using the day-night difference, the cumulative-sum-derived magnitude of circadian alteration, the Fourier amplitude and the difference between the high and low blood pressure levels of the square-wave model. RESULTS: The daytime am systolic blood pressure was, on average, 21 mmHg lower than the clinic systolic blood pressure, whereas diastolic pressure was, on average, similar with both techniques of measurement. Clinic levels of blood pressure in the 141 patients who underwent repeat measurements and the parameters describing the difference between the daily high and low spans of blood pressure were equally reproducible. However, both were less reproducible than the ambulatory blood pressure levels. The reproducibility coefficients, expressed as percentages of near maximum variation, were 49 and 50% for the clinic systolic and diastolic blood pressures, 30 and 32% for the mean 24 h systolic and diastolic blood pressures and 45-55% for the parameters describing the daily alteration between the high and low spans of blood pressure. CONCLUSION: Values of blood pressure in old patients with isolated systolic hypertension were more reproducible for ambulatory than they were for clinic measurements. Levels in patients selected because they have a high clinic blood pressure may be substantially higher with conventional than they are with daytime ambulatory measurement. The prognostic significance of this difference for the present patients is currently under investigation.     

Effect of guinea-pig purified immunoglobulin G1 on the responsiveness of tracheal, aortic, vas deferens and ileum smooth muscles

Background Smooth muscles hyperresponsiveness is a common feature in anaphylaxis and allergic diseases. Objective The aim of the present work was to investigate the effect of in vitro passive sensitization with highly purified immunoglobulin GI (IgGl) on the responsiveness of tracheal, aortic, vas deferens and ileum smooth muscles. Method Firstly, IgGl, obtained from actively sensitized BFA guinea-pigs, was purified by Protein A-Sepharose column and characterized by enzyme-linked immunosorbent assay (ELISA) and immunoelectrophoresis analysis. Concentration-response curves to spasniogens (acelylcholine for trachea and vas deferens, noradrenaline for aorta and histamine for ileum) were established before and after in vitro passive sensitizalion with IgGl. Results Contractile responses and maximal contractions were significantly enhanced after passive sensitization for all the organs. Maximal contractions were significantly increased in the trachea (+46.7%), aorta (+51%), vas deferens (+114.2%) and ileum (+ 117.2%). At the end of the experiments, the application of the sensitizing antigen induced a significant Schultz-Dale reaction of the smooth muscles. Conclusion The present results show that the in vitro application of purified IgGl can produce non-specific smooth muscle hyperreactivity and hypersensitivity. So, IgGl can be considered as the main factor involved in the genesis of sensitization-induced hyperresponsiveness, and probably play a great role in hyperreactivity observed during allergic diseases and anaphylaxis.