Biomedical subjects

R Cubeddu

Publications and source records attributed to R Cubeddu.

41 records · Page 3Linked to original sources

PubMed1987

Photodynamic therapy in vitro and in vivo with hematoporphyrin derivative and laser light.

Photodynamic therapy is currently under investigation as a new form of treatment for solid malignant tumors in animals and in humans. The method involves photosensitization of drugs and fluorescent dyes, such as hematoporphyrin derivative (Hpd), after preferential incorporation by neoplastic cells. In in vitro experiments laser light activation completely destroys Hpd-pretreated EL4 cells. Mice bearing MS-2 fibrosarcoma treated with Hpd and laser light survived indefinitely, in comparison with control animals that were untreated or treated only with Hpd or laser light. In mice bearing the highly metastatic tumors B16 melanoma and Lewis lung carcinoma (LLC) treated with Hpd and laser light delivered through a quartz fiber optic significantly prolonged the median survival time. This therapy was compared with surgical excision of primary tumors and, for superficial nonmetastatic neoplasma MS-2, the photodynamic therapy was more effective than surgery, while for metastatic tumors B16 and LLC, there was no significant difference between the two methodologies. However, phototherapy is much less traumatic to the animals.

Animals↗

PubMed1984

Hematoporphyrin derivative photochemotherapy of spontaneous animal tumors: clinical results with optimized drug dose.

Hematoporphyrin derivative (HpD) photochemotherapy was performed on 13 primary spontaneous tumors in dog and cat. The animals received an optimized drug dose of 5 mg/kg body wt i.v. 48 h before the first treatment with laser light at 631 nm. An evaluation of the clinical results is presented and discussed. Complete disappearance of the primary tumors was obtained in all cases with one or more light irradiations. Five cases presented recurrences that were cured with a further treatment. In 4 cases treated after surgical exeresis of the primary tumors, this therapy resulted in complete cure.

Animals↗

PubMed1983

Hematoporphyrin derivative photoradiation therapy in murine solid tumors.

The cytocidal activity of light-activated hematoporphyrin derivative (Hpd) in experimental and human tumors is under investigation in many laboratories. This activity is based upon preferential incorporation of Hpd in malignant tissues and its photosensibilization by red light. Treatment of mice bearing MS-2 fibrosarcoma and B16 melanoma, a metastastic tumor, with Hpd and laser light, externally or delivered through a quartz fiber optic imbedded directly into the tumor, significantly prolonged the median survival time. This therapy was compared with surgical excision of primary tumors, and preliminary results on metastatic neoplasm suggest that the photoradiation therapy is more effective than surgery.

Animals↗

PubMed1983

Effects of laser irradiation on hematoporphyrin-treated normal and transformed thyroid cells in culture.

Laser irradiation of tissues treated in vivo with the hematoporphyrin derivative (HPD) is known to result in a cytocidal effect, reportedly more pronounced in the tumor than in the surrounding normal tissues. In order to ascertain if this phenomenon had a clear cellular basis, it has been now reproduced in vitro in a model system consisting of normal and transformed cell lines. Epithelial rat thyroid cells were infected and transformed with a RNA oncogenic virus. Both the original (normal) and the viral-transformed (tumorigenic) cells were incubated with HPD and exposed to two types of laser irradiation: 631 nm, continuous wave; and 337.1 nm, pulsed. Under the conditions tested, the percentage survival of the transformed cells was found to be lower (up to approximately 3 times) than that of the normal cells. The cytocidal effect was greater using the pulsed than using the continuous-wave irradiation. The difference between normal and tumor cells was more evident at 30 micrograms than at 50 micrograms of HPD per ml. The HPD not followed by laser irradiation had no effect on the cell growth rate. The findings of a significant difference in the sensitivity to photoactivated HPD between normal and tumor cells under strictly controlled and highly comparable conditions opens new possibilities to the study of the cellular and molecular mechanisms involved in the phototherapy of tumors. Furthermore, studies in vitro on the active components of the photosensitizer and on their selectivity towards the tumor cells, explained at a cellular level, will lead to better approaches to photochemotherapy in vivo.

Animals↗

PubMedDate not supplied

Determination of visible near-IR absorption coefficients of mammalian fat using time- and spatially resolved diffuse reflectance and transmission spectroscopy.

In-vivo optical spectroscopy and the determination of tissue absorption and scattering properties have a central role in the development of novel optical diagnostic and therapeutic modalities in medicine. A number of techniques are available for the optical characterization of tissue in the visible near-IR region of the spectrum. An important consideration for many of these techniques is the reliability of the absorption spectrum of the various constituents of tissue. The availability of accurate absorption spectra in the range 600 to 1100 nm may allow for the determination of the concentration of key tissue constituents such as oxy- and deoxy-hemoglobin, water, and lipids. The objective of the current study is the determination of a reliable absorption spectrum of lipid(s) that can be used for component analysis of in-vivo spectra. We report the absorption spectrum of a clear purified oil obtained from pig lard. In the liquid phase above 36 degrees C, the oil is transparent and thus suitable for collimated transmission measurements. At room temperature, the oil is a solid grease that is highly scattering. The absorption and scattering properties in this solid phase are measured using time- and spatially resolved diffuse reflectance spectroscopy. Using these three independent measurement techniques, we have determined an accurate estimate for the absorption spectrum of mammalian fat.

Adipose Tissue↗