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Biomedical subjects

M Panjehpour

Publications and source records attributed to M Panjehpour.

At least 19 recordsLinked to original sources
PubMed1999

Photodynamic therapy for Barrett's esophagus: follow-up in 100 patients.

BACKGROUND: This report presents clinical results of photodynamic therapy in patients with Barrett's esophagus and dysplasia or superficial esophageal cancer. METHODS: One hundred patients including 13 with superficial cancers were treated. Light (630 nm) was endoscopically delivered to the esophageal mucosa by a diffuser or a windowed esophageal centering balloon. Nd:YAG laser was required to ablate small residual areas of Barrett's mucosa during-long-term follow-up. Patients were maintained on omeprazole and were followed for 4 to 84 months (mean 19 months). RESULTS: Conversion of approximately 75% to 80% of treated Barrett's mucosa to normal squamous epithelium was found in all patients; complete elimination of Barrett's mucosa was noted in 43 patients. Dysplasia was eliminated in 78 patients. Dysplasia developed during follow-up in 11 of 48 patients in untreated Barrett's mucosa requiring additional therapy. Ten of the 13 malignancies were ablated. Esophageal strictures occurred in 34%. Use of longer centering balloons reduced the incidence of strictures. CONCLUSION: Photodynamic therapy alone or with Nd:YAG laser thermal ablation combined with long-term acid inhibition provides an effective endoscopic therapy to (1) eliminate Barrett's mucosal dysplasia and superficial esophageal cancer and (2) reduce the extent of and, in some cases, eliminate Barrett's mucosa.

Adenocarcinoma↗
PubMed1998

Laser-induced fluorescence for esophageal cancer and dysplasia diagnosis.

A method using laser-induced fluorescence (LIF) for in vivo cancer diagnosis of the esophagus is described. Autofluorescence of normal and malignant tissues was measured directly using a fiberoptic probe inserted through an endoscope. The measurements were performed in vivo during routine endoscopy. Measurement of the fluorescence signal from the tissue was performed using laser excitation at 410 nm. The methodology was applied to differentiate normal and malignant tumors of the esophagus. The results of this LIF approach were compared with histopathology results of the biopsy samples and indicated excellent agreement in the classification of normal and malignant tumors for the samples investigated. The LIF procedure could lead to the development of a rapid and cost-effective technique for cancer diagnosis.

Barrett Esophagus↗
PubMed1997

Photodynamic therapy for Barrett's esophagus: cardiac effects.

BACKGROUND AND OBJECTIVE: Atrial fibrillation has been reported following esophageal photodynamic therapy. This study presents the results of serial cardiac testing following photodynamic therapy for patients with Barrett's esophagus and with dysplasia or early carcinoma. STUDY DESIGN/MATERIALS AND METHODS: Twelve patients were treated using photodynamic therapy. Serum creatinine phosphokinase and lactic dehydrogenase isoenzyme levels were determined pretreatment and 24, 48, and 72 hours after treatment. Electrocardiograms were obtained before and 48 hours after treatment. A rhythm strip was obtained 1 week posttreatment. Clinical assessment for cardiac arrhythmias occurred daily following therapy. RESULTS: Transient atrial fibrillation was noted in one patient during a follow-up endoscopy. However, no significant or permanent abnormality was noted in cardiac enzymes or electrocardiograms. CONCLUSION: No permanent electrocardiographic changes or significant abnormalities in cardiac enzymes were detected following esophageal photodynamic therapy in patients with or without histories of cardiac disease. Delivery of esophageal PDT is not associated with permanent adverse cardiac effects.

Adult↗
PubMed1997

Photodynamic therapy for Barrett's esophagus.

In summary, in a group of 55 patients with Barrett's esophagus and dysplasia, the authors have reported the ablation of seven superficial cancers, the elimination of dysplasia in 42 of the 55 patients, the complete elimination of Barrett's mucosa in 16 patients, and the reduction of the extent of Barrett's mucosa in all patients who were treated with PDT and were maintained on long-term omeprazole. Repeated PDT sessions were required in some patients to accomplish elimination of dysplasia. Esophageal strictures occurred in 53% of patients, but were treated satisfactorily with dilation. Current results using 5- and 7-cm centering balloons has shown a dramatic reduction in the incidence of stricture formation. Mucosal injury with these balloons is less than with diffusers or shorter balloons that require overlapping of treated areas. The authors are carefully following the patients treated with longer PDT balloons to evaluate the long-term effects on dysplasia. Lugol's staining is an important technique to identify residual patches of Barrett's mucosa following PDT. Small residual patches of Barrett's mucosa can be successfully destroyed with Nd: YAG laser therapy. The authors' results indicate that PDT alone or in combination with thermal ablation can eliminate superficial cancers, dysplasia, and Barrett's mucosa in many patients with Barrett's esophagus.

Barrett Esophagus↗
PubMed1996

Balloon photodynamic therapy of esophageal cancer: effect of increasing balloon size.

BACKGROUND AND OBJECTIVE: Photodynamic therapy is currently being used to treat various malignancies including esophageal cancer. The effect of photodynamic therapy depends upon the concentration of photosensitizing drug, light energy delivered to tissue, and the presence of oxygen in the targeted tissue. We have found that an esophageal centering balloon improves light delivery to esophageal mucosa. However, balloon pressure on esophageal mucosa could possibly reduce mucosal blood flow and oxygenation, therefore reducing the effect of photodynamic therapy. This study was conducted to investigate the effect of balloon pressure on the esophageal wall during photodynamic therapy in the canine esophageal model. STUDY DESIGN/MATERIALS AND METHODS: Studies were performed in the canine esophagus of ten animals to investigate whether increasing the size of the centering balloon, and hence the pressure on esophageal mucosa, would alter the tissue effect of PDT. Porfimer sodium 4 mg/Kg was administered and 630 nm light was delivered via a 1 cm diffuser located in the center of a 360 degrees 2 cm windowed balloon. Mucosal light measurements were made to ascertain equivalent mucosal light dosing of approximately 25 J/cm2. Endoscopic and necropsy findings obtained following photodynamic therapy with 25 mm, 33 mm, and 35 mm balloons were compared. RESULTS: In larger dogs (groups A and B), increasing the size of the esophageal centering balloon from a 25-33 mm size did not result in an overly tight fit nor was the increase associated with significant change in the PDT effect. In contrast, increasing the balloon size to 35 mm in smaller dogs (group C) resulted in a tight fit of the balloon in the esophagus and in significant reduction in the PDT effect on mucosal damage when mucosal equivalent light dose was administered during photodynamic therapy in the canine esophageal model. CONCLUSION: Increasing centering balloon size resulted in reduced tissue damage when mucosal equivalent light dose was administered during photodynamic therapy in the canine esophageal model. Proper sizing of centering balloons will be necessary for balloon PDT of esophageal mucosal dysplasia or cancer in humans.

Animals↗
PubMed1996

Endoscopic fluorescence detection of high-grade dysplasia in Barrett's esophagus.

BACKGROUND & AIMS: Early detection and treatment of esophageal cancer in Barrett's esophagus may improve patient survival if dysplasia is effectively detected at endoscopy. Typically, four-quadrant pinch biopsy specimens are taken at 2-cm intervals. This study was conducted to determine whether laser-induced fluorescence spectroscopy could be used to detect high-grade dysplasia in patients with Barrett's esophagus. METHODS: Four hundred ten-naonometer laser light was used to induce autofluorescence of Barrett's mucosa in 36 patients. The spectra were analyzed using the differential normalized fluorescence (DNF) index technique to differentiate high-grade dysplasia from either low-grade or nondysplastic mucosa. Each spectrum was classified as either premalignant or benign using two different DNF indices. RESULTS: Analysis of the fluorescence spectra from all patients collectively using the DNF intensity at 480 nm (DNF480) index showed that 96% of nondysplastic Barrett's esophagus samples were classified as benign, all low-grade dysplasia samples as benign, 90% of high-grade dysplasia samples as premalignant, and 28% of low-grade with focal high-grade dysplasia samples as premalignant. Using the two DNF indices concurrently, all patients with any high-grade dysplasia were classified correctly. CONCLUSIONS: Laser-induced fluorescence spectroscopy has great potential to detect high-grade dysplasia in Barrett's esophagus when using the DNF technique.

Adult↗
PubMed1996

Photodynamic therapy in Barrett's esophagus.

OBJECTIVES: This report presents clinical results using photodynamic therapy for dysplasia and superficial esophageal cancer in Barrett's esophagus. METHODS: Forty-five (45) patients with Barrett's esophagus and dysplasia were treated with photodynamic therapy using sodium porfimer 2.0 mg/kg as the photosensitizing drug. Fifteen patients also had 16 superficial esophageal cancers (0-1.5 cm; Tis-T2, N-0, M-0). Red light (630 nm) was delivered to the esophageal mucosa by a diffuser inserted through the endoscope or via a windowed esophageal centering balloon designed to improve targeted delivery of light during photodynamic therapy. Patients were maintained on omeprazole and were followed for 6-62 months following photodynamic therapy. RESULTS: Photodynamic therapy produced mucosal damage in treated areas. Ablation of dysplastic or malignant mucosa was followed by healing and conversion of approximately 75-80% of treated Barrett's mucosa to normal squamous epithelium in all patients. Complete elimination of Barrett's epithelium was found in 16 patients. Areas of dysplasia were eliminated in 35 of the 45 patients. All 16 malignancies were ablated. No cancer recurrence was found in follow-up. Healing was associated with esophageal strictures in 58%, which were treated successfully by esophageal dilation in all patients. CONCLUSION: Photodynamic therapy combined with long-term acid inhibition provides an effective endoscopic therapy to (1) eliminate Barrett's mucosal dysplasia and superficial esophageal cancer and (2) reduce the amount of and, in some cases, eliminate Barrett's mucosa.

Adenocarcinoma↗
PubMed1996

Photodynamic therapy for Barrett's esophagus: clinical update.

OBJECTIVES: This report presents clinical results of photodynamic therapy for dysplasia and superficial esophageal cancer in Barrett's esophagus. METHODS: Thirty-six patients with Barrett's esophagus and dysplasia were treated with photodynamic therapy, and sodium porfimer 2.0 mg/kg was used as the photosensitizing drug. Fourteen patients also had 15 superficial esophageal cancers (0-1.5 cm; ultrasound-T2,N-0,M-0). Red light (630 nm) was delivered to the esophageal mucosa by a diffuser inserted through the endoscope or via a windowed esophageal centering balloon designed to improve targeted delivery of light during photodynamic therapy. Patients were maintained on omeprazole and were followed for 6-62 months after photodynamic therapy. RESULTS: Photodynamic therapy produced extensive mucosal damage in treated areas. Ablation of dysplastic or malignant mucosa was followed by healing and conversion of approximately 75-80% of treated Barrett's mucosa to normal squamous epithelium in all patients. Complete elimination of Barrett's epithelium was achieved in 10 patients. Areas of dysplasia were eliminated in 29 patients, and all 15 malignancies were ablated. No cancer recurrence was found in follow-up. Healing was associated with esophageal strictures (four were severe) that were treated successfully by esophageal dilation in 21 patients. CONCLUSION: Photodynamic therapy combined with long-term acid inhibition provides effective endoscopic therapy that 1) eliminates Barrett's mucosal dysplasia and superficial esophageal cancer, and 2) reduces the amount of, or, in some cases, eliminates Barrett's mucosa.

Adenocarcinoma↗
PubMed1995

In vivo cancer diagnosis of the esophagus using differential normalized fluorescence (DNF) indices.

BACKGROUND AND OBJECTIVE: We report the use of new diagnostic parameters based on the differential normalized fluorescence (DNF) signals for malignant tumor diagnosis. STUDY DESIGN/MATERIALS AND METHODS: Over 200 measurements of endogenous fluorescence from normal and malignant esophageal tissues were performed during routine endoscopy in 48 patients. A pulsed nitrogen-pumped dye laser was used to provide in situ excitation at 410 nm. Direct collection of the fluorescence signal emitted by the tissue was achieved using an intensified photodiode array detector equipped with a fiberoptic probe. RESULTS: The fluorescence signals were normalized with respect to the total fluorescence signal area. The cancer diagnosis indices were defined by the difference between the normalized fluorescence signal of a tumor and the mean value of a reference set of normal tissues. The results of the DNF approach were compared with endoscopic examinations and histopathology interpretations of the biopsy samples. Excellent correlation in the classification of normal and malignant tumors for the samples was found. CONCLUSION: The data indicated that the DNF approach has a significant potential to provide a direct, real-time, and in-situ technique for cancer diagnosis of the esophagus without requiring biopsy of the tumors and time-consuming histopathology tests.

Adenocarcinoma↗
PubMed1995

Spectroscopic diagnosis of esophageal cancer: new classification model, improved measurement system.

Laser-induced fluorescence spectroscopy was used to measure fluorescence emission of normal and malignant tissue during endoscopy in patients with esophageal cancer and volunteers with normal esophagus. The spectroscopy system consisted of a nitrogen-pumped dye-laser tuned at 410 nm for excitation source, an optical multichannel analyzer for spectrum analysis, and a fiberoptic probe designed for both the delivery of excitation light and the collection of fluorescence emission from tissue. The fluorescence lineshape of each spectrum was determined and sampled at 15-nm intervals from 430 to 716 nm. A calibration set of spectra from normal and malignant spectra was selected. Using stepwise discriminate analysis, significant wavelengths that separated normal from malignant spectra were selected. The intensities at these wavelengths were used to formulate a classification model using linear discriminate analysis. The model was then used to classify additional tissue spectra from 26 malignant and 108 normal sites into either normal or malignant spectra. A sensitivity of 100% and specificity of 98% were obtained.

Algorithms↗
PubMed1994

Photodynamic therapy for esophageal cancer using a 180 degrees windowed esophageal balloon.

Although delivery of uniform circumferential light is desirable during photodynamic therapy of advanced esophageal cancer in humans, early esophageal cancer may need only targeted treatment. Studies were performed in the canine esophagus of eight animals to investigate whether use of a "windowed" (shaded) centering balloon would improve targeted illumination of esophageal mucosa for photodynamic therapy. Shaded balloons were developed with a 2-cm-long, 360 degrees or 180 degrees clear "window." Photofrin 4 mg/Kg was used as the photosensitizer. Light at 630 nm was delivered at 300 J/cm or 600 J/cm. Isotropic probes placed on the balloon wall allowed real-time measurement and verification of relatively uniform light doses delivered to esophageal mucosa during balloon photodynamic therapy. With the windowed balloon, targeted delivery of photodynamic therapy was possible. Using the 180 degrees balloon, mucosa exposed to illumination was destroyed, whereas mucosa protected from light by the balloon shading was undamaged. Healing was complete and strictures did not occur. The shading of the balloon protected normal mucosa and prevents the formation of esophageal strictures. The "windowed" centering balloon provides a technology and technique that allows targeted delivery of uniform light during esophageal PDT.

Animals↗
PubMed1994

Tumor cell-enhanced sensitivity of vascular endothelial cells to photodynamic therapy.

Effective antitumor photodynamic therapy (PDT) may be related to damage of vasculature within the tumor. The purpose of this study was to determine if tumor cells secrete factors that stimulate proliferation of human umbilical vein endothelial cells (HUVEC) and result in enhanced sensitivity of HUVEC to aluminum-sulfonated phthalocyanine (AlSPc)-PDT. Three human tumor cell lines--pharyngeal squamous carcinoma, colonic carcinoma, and mammary carcinoma--were used in this study. Co-culture of HUVEC and either squamous carcinoma or colonic carcinoma, but not mammary carcinoma, significantly increased HUVEC proliferation and AlSPc-PDT mediated cell damage. In addition, supernatant from squamous carcinoma and colonic carcinoma cultures also stimulated HUVEC proliferation and sensitivity to AlSPc-PDT. Both supernatant and cell lysate from squamous carcinoma cells contained angiogenic factors consistent with basic and acidic fibroblast growth factors, as evidenced by Western blot analysis and BALB/c 3T3 fibroblast cell proliferation assays. Collectively, these results suggest that selected tumor cell lines produce angiogenic factors that induce HUVEC proliferation and subsequently enhance sensitivity to AlSPc-PDT.

3T3 Cells↗
PubMed1993

Quantification of phthalocyanine concentration in rat tissue using laser-induced fluorescence spectroscopy.

Quantification of photosensitizer concentration in tissue should improve planning and outcome of photodynamic therapy. Laser-induced fluorescence (LIF) can be used to measure in vivo fluorescence of photosensitizers in tissue. This study was designed to determine if in vivo fluorescence intensity of chloroaluminum phthalocyanine tetrasulfonate correlates with its concentration in different rat tissues. Following LIF measurements, the animals were humanely euthanized and the concentration of phthalocyanine in different tissues was determined using chemical extraction technique. The correlation of phthalocyanine fluorescence intensity and its concentration was determined for each tissue using Pearson product-moment correlation analysis. A strong correlation between in vivo phthalocyanine fluorescence intensity and its concentration was found for spleen, kidney, liver, and chemically induced mammary adenocarcinoma. Low correlation was found for thigh skin and planum of nose. No correlation was found for thigh muscle and tongue.

Animals↗
PubMed1993

Comparative study between pulsed and continuous wave lasers for Photofrin photodynamic therapy.

A study was conducted in the normal canine esophagus to compare continuous wave (CW) and pulsed laser light for photodynamic therapy with Photofrin (4 mg/kg). Forty-eight hours post-injection, 630 nm laser light (CW light from an argon-pumped dye-laser and pulsed light from a KTP/532-pumped dye-laser) was delivered using a 24 mm diameter cylindrical esophageal PDT balloon positioned at either distal or proximal esophagus. A 1.0 cm cylindrical diffuser placed in the center of the balloon delivered 300 J/cm of light at an intensity of 400 mW/cm. Three dogs received CW light proximally and pulsed light distally. Four dogs received CW light distally and pulsed light proximally. The light dose delivered to the esophageal mucosa was measured using three isotropic probes placed on the balloon wall. Laser-induced fluorescence technique was used to compare photosensitizer fluorescence intensities at distal and proximal locations. Similar mucosal light doses and drug fluorescence intensities were verified for sites receiving pulsed or CW laser light. Two days after light delivery, the dogs were endoscoped to evaluate the severity of the lesions. While some response variability was observed among different animals, endoscopic examination of the lesions revealed comparable injury from CW and pulsed light in each subject. The animals were then euthanized and necropsies were performed. Based on the gross and histological examination of the lesions, the CW and pulsed laser-induced injuries could not be distinguished.

Animals↗
PubMed1993

Cytokine modulation of endothelial cell sensitivity to photodynamic therapy.

The purpose of this study was to determine if recombinant angiogenic cytokines modulate the sensitivity of endothelial cells to the toxic effects of chloroaluminum sulphonated phthalocyanine (AlSPc) photodynamic therapy (PDT). Bovine pulmonary artery endothelial cells in 24-well tissue culture plates were pretreated for 24 hr with AlSPc and either acidic fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), tumor necrosis factor-alpha (TNF), interleukin-1-alpha (IL-1), or transforming growth factor-beta (TGF) followed by argon-pumped dye laser. Endothelial cell damage was monitored with 51chromium release. FGF, TGF, and, to a lesser extent, IL-1, enhanced the PDT-mediated damage to endothelial cells, whereas PDGF and TNF did not significantly modulate toxicity. The enhanced endothelial cell damage was seemingly not related to rate of cell proliferation or amount of photoactive drug uptake by the EC. These results suggest that presence of tumor secreted cytokines may enhance PDT-mediated toxicity of tumor associated endothelial cells.

Aluminum↗
PubMed1992

Centering balloon to improve esophageal photodynamic therapy.

A cylindrical balloon was developed to improve delivery of circumferential light for photodynamic therapy (PDT) of esophageal carcinoma. The balloon consisted of a 36-mm-long clear cylindrical membrane and a central tube to hold a cylindrical diffuser in the center of the lumen. Three isotropic probes were placed on the outside of the balloon to allow measurement of delivered light dose to the esophageal mucosa. The balloon was tested in the normal esophagus of 8 dogs that were injected with 4.0 mg/kg of PHOTOFRINR. Endoscopy was performed 48 hours following the injection, and under endoscopic observation the balloon assembly was passed, fixed in place, and inflated. A 1-cm cylindrical diffuser was passed into the central tube and 150, 300, and 600 Joules/cm of 630 nm laser light was delivered at 25 cm, 15 cm, and 5 cm proximal to the gastroesophageal junction. One control dog was illuminated using the cylindrical diffuser alone at doses of 300 and 600 Joules/cm of diffuser. Complete circumferential tissue response was obtained when the balloon was used. Relatively uniform light intensities were measured around the lumen. In contrast, noncircumferential and unpredictable PDT responses were generated when the cylindrical diffuser was used without the balloon.

Animals↗
PubMed1991

Nd:YAG laser-induced hyperthermia treatment of spontaneously occurring veterinary head and neck tumors.

Conventional hyperthermia treatment of superficial tumors in the oral cavity is troublesome due to difficulty in accessing the lesion. A new hyperthermia technique employing near-infrared radiation delivered through a flexible silica optical fiber is described. The system consisted of an Nd:YAG laser for tissue heating, a He-Ne laser for aiming beam, a computer-controlled optical shutter, an interstitial thermometer, computer, and a printer. A 3-m-long 600-microns silica fiber delivered laser energy to the tumor via surface illumination. Using the aiming beam, the spot size was adjusted to include 5 mm of surrounding normal tissue. A thermocouple implanted in the tumor base provided temperature feedback to maintain desired hyperthermic temperature within the lesion. Three spontaneously occurring canine (two squamous cell carcinomas on the gum, one pigmented melanoma on the hard palate) and one feline tumor (squamous cell carcinoma on the nose) have been treated with Nd:YAG laser hyperthermia. Hyperthermia was delivered at 43.5 degrees C for 1 h. All animals received standard radiation treatment prior to hyperthermia. Nd:YAG laser hyperthermia allowed effective and efficient delivery of heat to veterinary nasal and oral lesions otherwise not treatable with conventional heating techniques.

Aluminum Silicates↗