Shape-memory alloy loop snare for endoscopic photodynamic therapy of early gastric cancer

Shaping tissue with shape memory materials

After being severely and quasi-plastically deformed, shape memory materials are able to return to their original shape at the presence of the right stimulus. After a brief presentation about the fundamentals, including various shape memory effects, working mechanisms, and typical shape memory materials for biomedical applications, we summarize some major applications in shaping tissue with shape memory materials. The focus is on some most recent development. Outlook is also discussed at the end of this paper.

Induction of cell death by photodynamic therapy with a new synthetic photosensitizer DH-I-180-3 in undifferentiated and differentiated 3T3-L1 cells

To examine the photodynamic therapy (PDT) effect on adipocytes, we investigated whether PDT using DH-I-180-3, a new synthetic lipophilic photosensitizer, induced cell death of both undifferentiated and differentiated 3T3-L1. 3T3-L1 pre-adipocytes were differentiated into adipocytes in the culture medium containing pantothenate, insulin, dexamethasone, isobutylmethylxanthine, and troglitazone. PDT was applied to both undifferentiated and differentiated 3T3-L1. Photosensitizer uptake in fat cells was determined by measuring its mean fluorescence intensity. DH-I-180-3 mediated effectively PDT-induced cell death of both pre-adipocytes and adipocytes. And the photosensitizer was accumulated more rapidly in 3T3-L1 adipocytes, compared with other cancer cell lines. These results demonstrate that PDT is a potent cell death inducer in pre-adipocytes and adipocytes. Thus, PDT with DH-I-180-3 may be applied for a new therapeutic modality for obesity treatment.

Uses of photodynamic therapy in premalignant and malignant lesions of the gastrointestinal tract beyond the esophagus

Much has recently been written regarding the use of photodynamic therapy for the treatment of esophageal carcinoma and dysplastic Barrett's esophagus. This review, however, describes the clinical experience using photodynamic therapy with various photosensitizer agents for the treatment of diseases in other areas of the gut, especially the pancreaticobiliary tract where European studies have established the role of porfimer sodium photodynamic therapy in the management of patients with cholangiocarcinoma.

Photodynamic therapy of superficial esophageal cancer with a transparent hood

BACKGROUND

To improve the effectiveness of photodynamic therapy, the further development of endoscopic devices is essential. For photodynamic therapy of superficial esophageal cancer, a transparent hood was used to obtain precise laser irradiation.

METHODS

The transparent hood was attached to the tip of an upper endoscope. Forty-eight hours after the injection of porfimer sodium, cancerous lesions were irradiated with an excimer-dye laser (4 mJ, 80 Hz). Twenty-four hours later, additional irradiation was applied to lesions when the response to the initial irradiation appeared insufficient. Fifteen neoplastic lesions in 7 patients were treated.

RESULTS

The initial size of the lesions ranged from 5 to 30 mm in diameter. Histopathologically, there were 9 squamous-cell carcinomas and 6 high-grade squamous dysplastic lesions. All treated lesions disappeared after the first or the second laser irradiation (total energy range 39.1-193.5 J/cm(2)). During follow-up (range 4-51 months), there was no recurrence of the initial lesion in any patient. There was no severe photodynamic therapy related complication.

CONCLUSIONS

Photodynamic therapy with a transparent hood is an acceptable option for the treatment of superficial esophageal cancer.