Experimental photodynamic treatment of canine bladder.

In urology, important limiting factors in the application of hematoporphyrin derivative and photodynamic therapy appear to be the problems of standardization of dosimetry and the technique of transurethral photoradiation. Experimental photodynamic therapy on canine bladder with normal and altered epithelium was performed using an argon laser as an energy source. A 630 nanometer wavelength of light was delivered through a quartz-optical fiber with either a regular flat end for focal illumination or a bulb-type end which produced an isotropic light pattern.

Potentiation of photodynamic therapy by heat: effect of sequence and time interval between treatments in vivo.

Photodynamic therapy (PDT) utilizing hematoporphyrin derivative (Hpd) as photosensitizer and an argon-dye laser as the light source was used alone and in combination with a localized microwave hyperthermia treatment to treat the SMT-F mammary carcinoma in mice. A 30-min heat treatment at 44.5 degrees C was applied 0-8 hr before or after a standard photodynamic treatment (67.

N-hydroxycarbamate is the substrate for the pyruvate kinase catalyzed phosphorylation of hydroxylamine.

The true substrate for the pyruvate kinase catalyzed phosphorylation of hydroxylamine at high pH which is activated by bicarbonate is shown to be N-hydroxycarbamate, since a lag is seen when the reaction is started by the addition of bicarbonate or hydroxylamine but a burst appears when it is started with a mixture of the two. The lag can be diminished by addition of carbonic anhydrase but not eliminated, showing that CO2 is an intermediate in the formation of the carbamate and that both the formation of CO2 and the subsequent reaction of CO2 with hydroxylamine limit the rate of carbamate formation. The equilibrium constant for the reaction bicarbonate + hydroxylamine reversed N-hydroxycarbamate is 1.

Photoradiation of rabbit ocular malignant melanoma sensitized with hematoporphyrin derivative.

Photoradiation therapy (PRT) against the Greene-Harvey amelanotic malignant melanoma on the rabbit iris was effectively used to cause tumor regression. A dose of 2.5 mg/kg of hematoporphyrin derivative (HPD) given intravenously, followed by photoradiation at a wavelength of 632 nm and a power density as low as 71 mW/cm2 for 24 minutes (102 J/cm2) was found to be lethal for tumors 4 mm in diameter with an acceptable level of reversible toxicity to the surrounding tissues.

Interaction of hyperthermia and photoradiation therapy.

Local microwave hyperthermia (2450 MHz) was applied to axillary implants of the SMT-F mammary carcinoma in mice in combination with photoradiation therapy (PRT) in an attempt to determine if the two modalities interact. When 40.5 degrees C was applied for 30 min immediately prior to or immediately following PRT (630-nm light, 30 min, at 75 mW/cm2, 20-24 hr post 7.

Photodynamic therapy (PDT) of malignant tumors.

Photodynamic therapy (PDT) is finding increasing application to a number of malignant tumors. It is based on the specific photosensitization of malignant tissue by a particular porphyrin derived from hematoporphyrin, known as Photofrin II. The exact structure at present is unknown.

Enhanced tumor control following sequential treatments of photodynamic therapy (PDT) and localized microwave hyperthermia in vivo.

Photodynamic therapy (PDT), or photoradiation therapy (PRT), utilizing hematoporphyrin derivative (HPD) as photosensitizer and an argon-dye laser system as the light source, was used alone and in combination with localized microwave hyperthermia (2450 MHz) to treat axillary tumors of the SMT-F mammary carcinoma in mice. Thirty-minute heat treatments were applied either immediately before or immediately after a standard PDT treatment of 630 nm light at 75 mW/cm2 for 30 min (135 J/cm2) given 24 hr post-7.5 mg/kg HPD, intraperitoneally (i.

Photoradiation therapy in advanced carcinoma of the trachea and bronchus.

Photoradiation therapy is a new technique being investigated for the treatment of solid malignant tumors. In this study, 17 patients with advanced, recurrent, biopsy-proven malignant lesions of the trachea or main-stem bronchus were treated by photoradiation therapy. Patients received hematoporphyrin derivative intravenously three days prior to light therapy.

Temperature rise during photoradiation therapy of malignant tumors.

This report discusses the optical and thermal distribution during photoradiation therapy of malignant tumors. Emphasis is put on the therapeutic procedure with the light dose delivered through an inserted optical fiber. Theoretical predictions and experimental results indicate that the temperature rise during the procedure may give rise to hyperthermal cell kill.

Peptidoglycan biosynthesis in Neisseria gonorrhoeae strains sensitive and intrinsically resistant to beta-lactam antibiotics.

Treatment of penicillin-sensitive and intrinsically resistant Neisseria gonorrhoeae strains with their respective inhibitory concentrations of penicillin caused rapid cell death. When the peptidoglycan syntheses of these two strains were examined in the presence of penicillin, the sensitive strain continued to make this cell wall polymer for an extended time, whereas the resistant strain underwent a rapid and marked depression in synthesis. Examination of the labeled sodium dodecyl sulfate-insoluble peptidoglycan made in the presence of inhibitory concentrations of penicillin revealed further differences.

Reimplantation of freeze-treated bone in immediate reconstruction of the mandible.

Surgical defects encountered with corrective surgery of the mandibular complex have been repaired most successfully with autogenous composite bone grafts. Their use belies inherent consequences associated with distant donor sites. Presented here are the experiences and results in two patients whose reconstructions consisted of immediate replacement of the resected mandibular segment after its devitalization with cryogenic freezing treatments.