Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Light application
Reexamination Certificate
2002-01-18
2003-09-23
Gibson, Roy D. (Department: 3739)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Light application
C607S089000, C128S898000
Reexamination Certificate
active
06623513
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a photodynamic therapy (PDT) or process, and more particularly to a photodynamic therapy or process utilizing a photosensitive material and pyrrolnitrin for in vitro and in vivo cellular and acellular organism eradication. The invention also relates to photodynamic eradication of bacteria, fungal, and viral wound infections and sterilization of tissue using a photosensitive material, such as methylene blue, methylene green, or toluidene blue, pyrrolnitrin, and a surfactant material, such as polymyxin B, SDS, cetrimide, or benzalkonium chloride. Additionally, the invention relates to photodynamic eradication of cancer cells, such as present within a tumor, by PDT in conjunction with a photosensitive material and pyrrolnitrin. The present invention advantageously uses light energy in combination with a photosensitive material, pyrrolnitrin, and a surfactant material to treat both in vitro and in vivo pathogens, including cancer cells and microbiological pathogens. The invention also relates to the eradication or destruction of biofilms via a photodynamic mechanism. The invention also relates to an apparatus and method of use for eradication of biofilms on a diverse range of medical products, such as intravascular catheters, endotracheal tubes, and implants. The invention further relates to an apparatus and method of use for eradication of cellular and acellular organisms within an air filtration or air decontamination device for eliminating or reducing harmful biological elements such as viruses, bacteria, and fungus. The invention further relates to the eradication of spores in both in vivo and in vitro applications.
BACKGROUND OF THE INVENTION
Abnormal cells and acellular organisms are known to selectively absorb certain dyes (photosensitive materials) delivered to a treatment site to a more pronounced extent than surrounding tissue. Once presensitized, abnormal cells or acellular organisms can be destroyed by irradiation with light of an appropriate wavelength corresponding to an absorbing wavelength of the photosensitive material, with minimal damage to surrounding normal tissue. This procedure, which is known as photodynamic therapy (PDT), has been clinically used to treat metastatic breast cancer, bladder cancer, head and neck cancers, esophageal cancer, lung cancer, and other types of malignant tumors, actinic keritosis, and macular degeneration.
PDT is generally used to treat hyperproliferating tissues, i.e. cancer, etc, by first administering a photosensitizer to the patient by a suitable route such as by intravenous [IV], intramuscular [IM], intraperitoneal [IP] injection, or oral administration, and then waiting for a predetermined period of time known to be sufficient to effect the preferential uptake and retention of the photosensitizer in the target tissue relative to the concentration of the photosensitizer in normal (non-hyperproliferating) tissues. By permitting time to elapse after systemic administration of the drug, the photosensitizer is generally localized in a variety of tissue/cell types as well as locations within the target tissue. The time for photosensitizer build-up in a target tissue varies but is in the range of 2-24 h. The resulting therapeutic response therefore generally involves a variety of cytological effects.
Photodynamic therapy (PDT) is a treatment that is based upon the differential uptake by cancerous cells of photosensitizing agents, followed by irradiation of the cells to cause a photochemical reaction that is believed to generate chemically disruptive species, such as singlet oxygen. These disruptive species in turn injure the cells through reaction with cell parts, such as cellular and nuclear membranes. Photodynamic therapy has been used successfully for treating several types of cancer cells.
Pyrrolnitrin is a known antibiotic which is particularly effective against fungal pathogens. Pyrrolnitrin is known as 3-Chloro-4-(3-chloro-2-nitrophenyl) pyrrole. Pyrrolnitrin is an antifungal antibiotic isolated from Pseudomonas pyrrocinia. Pyrrolnitrin may be biosynthesized from tryptophan. Proprietary preparations of pyrrolnitrin include MIEUTRIN and MICUTRIN. Another pyrrolnitrin containing compound is provided by Fujisawa Pharmaceutical Co., Ltd. Osaka, Japan.
Pyrrolnitrin is a phenylpyrrole derivative with strong antibiotic activity that has been shown to inhibit a broad range of fungi. Pyrrolnitrin was originally isolated from
Pseudomonas pyrrocinia,
but has since been isolated from Myxococcus species, Burkholdaria species, and several other Pseudomonas species such as Ps fluorescens. The compound has been reported to inhibit fungal respiratory electron transport and uncouple oxidative phosphorylation. It has also been proposed that pyrrolnitrin causes generalized lipoprotein membrane damage.
Air filtration devices and systems are known. Certain air filtration systems provide for eradication of biological pathogens using electromagnetic radiation. However, known electromagnetic radiation pathogen destruction techniques have significant limitations. For example, UV and microwave destruction approaches may only reduce the bacteria count, and not eradicate the pathogens altogether. Furthermore, bacteria may become resistant to UV eradication over relatively short periods of time. Microwave destruction is through generation of severe heat, i.e., 100 C. This modality would not be applicable as a portable biological weapon countermeasure. In comparison, photodynamic therapy antibacterial effects have demonstrated complete destruction and sterilization of highly concentrated bacterial species in vitro and therefore would appear to be superior to the above methods.
Many hospitalized patients, particularly patients in an Intensive Care Unit (“ICU”), must be fitted with endotracheal tubes to facilitate their respiration. An endotracheal tube is an elongate, semi-rigid lumen which is inserted into a patient's nose or throat and projects down into airflow communication with the patient's respiratory system. As such, the patient either directly, or with the aid of a respiratory unit, is able to breathe more effectively through the endotracheal tube. Endotracheal tubes may remain in place within a patient for an extended period of time, e.g. up to a 14 day period. Biofilm contamination of endotracheal tubes within intubated patients may lead to an increased rate of infection, particularly pneumonia. An effective apparatus and method of use for eradication of biofilm organism on endotracheal tubes of intubated patients is desired.
Occurrences of catheter related bloodstream infection (CRBSI) have increased in part as a result of the wide use of invasive medical devices, including intravascular catheters. CRBSI is one of the most common types of nosocomial bloodstream infection, a finding that has been attributed to the wide use of intravascular catheters in hospitalized patients. Recent interventions to control CRBSI include anticoagulant/antimicrobial lock, use of ionic silver at the insertion site, employment of an aseptic hub model, and antimicrobial impregnation of catheters.
Several factors pertaining to the pathogenesis of CRBSI have been identified. The skin and hub are the most common sources of colonization of percutaneous vascular catheters. For short-term, non-nontunneled, noncuffed catheters, the organisms migrate from the skin insertion site along the intercutaneous segment, eventually reaching the intravascular segment of the tip. For long-term catheters, the hub is a major source of colonization of the catheter lumen, which ultimately leads to bloodstream infections through luminal colonization of the intravascular segment.
The catheter surface is another factor relating to the pathogenesis of CRBSI. Organisms that adhere to the catheter surface maintain themselves by producing an “extracellular slime,” a substance rich in exopolysaccharides, often referred to as fibrous glycocalyx or microbial biofilm. Microorganisms bind to the surface of host p
Advanced Photodynamic Technologies, Inc.
Fulbright & Jaworski L.L.P.
Gibson Roy D.
Johnson, III Henry M.
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