Homogenization of tissues via picosecond-infrared laser (PIRL) ablation: Giving a closer view on the in-vivo composition of protein species as compared to mechanical homogenization.

Posttranslational modifications and proteolytic processing regulate almost all physiological processes. Dysregulation can potentially result in pathologic protein species causing diseases. Thus, tissue species proteomes of diseased individuals provide diagnostic information. Since the composition of tissue proteomes can rapidly change during tissue homogenization by the action of enzymes released from their compartments, disease specific protein species patterns can vanish. Recently, we described a novel, ultrafast and soft method for cold vaporization of tissue via desorption by impulsive vibrational excitation (DIVE) using a picosecond-infrared-laser (PIRL). Given that DIVE extraction may provide improved access to the original composition of protein species in tissues, we compared the proteome composition of tissue protein homogenates after DIVE homogenization with conventional homogenizations. A higher number of intact protein species was observed in DIVE homogenates. Due to the ultrafast transfer of proteins from tissues via gas phase into frozen condensates of the aerosols, intact protein species were exposed to a lesser extent to enzymatic degradation reactions compared with conventional protein extraction. In addition, total yield of the number of proteins is higher in DIVE homogenates, because they are very homogenous and contain almost no insoluble particles, allowing direct analysis with subsequent analytical methods without the necessity of centrifugation. BIOLOGICAL SIGNIFICANCE: Enzymatic protein modifications during tissue homogenization are responsible for changes of the in-vivo protein species composition. Cold vaporization of tissues by PIRL-DIVE is comparable with taking a snapshot at the time of the laser irradiation of the dynamic changes that occur continuously under in-vivo conditions. At that time point all biomolecules are transferred into an aerosol, which is immediately frozen.

Benign and malignant skin lesions in renal transplant recipients.

BACKGROUND: Skin lesions - benign and malignant - occur frequently in organ transplant recipients receiving long-term immunosuppressive therapy. These patients are at greater risk of skin cancers. AIMS: To study dermatologic problems in renal transplant recipients (RTRs). METHODS: One hundred patients (53 men and 47 women) were consecutively examined for benign and malignant skin complications since transplantation in Razi Hospital in Tehran Medical University. The main immunosuppressive therapy regimen in these patients was a combination of prednisolone, azathioprine, and cyclosporine. RESULTS: The early and most common complication was cosmetic side effects that occurred in 98% patients. Skin infections occurred in 83% of the patients and most of them were viral infections (65%), especially of human papilloma viruses (HPVs) in 40% of the patients. We found six cases of malignancy in these patients in that four cases were skin cancers, including one case of SCC, one BCC, and two cases of Kaposi's sarcoma. Dermatologic problems occur most frequently in RTRs, especially skin cancers which have higher frequency in these patients than general population, particularly, Kaposi sarcoma. Sun exposure has an important role in developing epithelial skin cancers following transplantation. The age of developing skin cancer in these patients was early than normal population. CONCLUSION: Our results emphasize the importance of dermatologic examinations and monitoring RTRs to obtain an early diagnosis and treatment of cutaneous manifestations.