Michael Bamberg

Spectral Differences between Stratum Corneum and Sebaceous Molecular Components in the Mid-IR:

Despite a number of studies on the composition of the lipids of stratum corneum (SC) and sebum, questions remain about the detailed molecular arrangement of the two superficial components of human skin. The investigation of the molecular components of SC in vivo is important to understand the function of what was once thought to be a “dead” epithelium. We have investigated the molecular composition of SC and sebum in vivo, in the mid-infrared, with fiber-based attenuated total reflection Fourier transform infrared spectroscopy (ATR/FT-IR). This technique combines the sensitivity of infrared spectroscopy in detecting molecular composition and conformational order with the capability of probing surfaces to a depth of less than 1 μm. ATR/FT-IR is therefore particularly useful for the investigation of interfaces such as SC and the sebaceous layers. We found that with the use of ATR/FT-IR one can distinguish between the contribution of the molecular components of sebum and SC. The presence of spectral “signatures” of the lipids of sebum allowed us to improve the interpretation of some infrared bands of sebaceous origin as well as of SC in vivo. We also found that ATR/FT-IR can be used to separate the spectral contributions of sebum and SC, and as a method to study the early recovery of superficial lipids after the removal of sebum. Following calibration, a method can be developed to quantify the relative amount of fatty acid in sebum with the use of ATR/FT-IR. We observed that the sebaceous fatty acids that reach the surface of the skin recover at a slower rate than other sebaceous lipids. Our investigation shows that fiber-based ATR/FT-IR is a promising spectroscopic approach to the study of epithelial surfaces and surface contaminants in vivo.

A rapid method to detect dried saliva stains swabbed from human skin using fluorescence spectroscopy.

Saliva on skin is important in forensic trace evidence. If areas where saliva is present can be outlined, this may lead to DNA analysis and identification. This study describes a rapid and non-destructive method to detect dried saliva on the surface of the skin by fluorescence spectroscopy. Eighty-two volunteers deposited samples of their own saliva on the skin of their ventral forearm. A control sample of water was deposited at three different sites on the contralateral arm. Saliva and water control were then allowed to air-dry. Swab samples were taken from dried saliva and control sites and were dissolved in 0.1M KCl solution. Emission spectra were obtained from the solution and were characterized by a principal maximum at 345-355nm with excitation at 282nm. The fluorescence emission intensity was greater than background readings obtained from the control swab site in 80 of 82 volunteers (approximately 97.6%). The fluorescence profile of saliva samples were similar to those obtained from aqueous samples of pure amylase and tryptophan, an endogenous fluorophore in alpha-amylase. The presence of an emission peak at 345-355nm with excitation at 282nm could provide a strong presumptive indication of saliva deposition.

Cytotoxicity of human brain tumors by hematoporphyrin derivative

A number of investigators have successfully applied light activation of hematoporphyrin derivative to treat both animal and human solid tumors [ 1, 2, 4, 111. The biological activity of this treatment modality depends on the selective retention of the HPD by malignant cells, activation by light with the resultant production of singlet oxygen, and the rapid cytotoxicity induced by oxidation-induced cell membrane lysis [9]. Brain tumors would seem to be an ideal system to apply this new treatment modality, since they are lethal by virtue of their local growth [8]. In addition, with new CT scan and fiberoptic technology, a very large area within the brain could be activated by laser-derived light systems. It was the purpose of this study to investigate the in vitro sensitivity of human central nervous system neoplasms to the cytotoxic effects of hematoporphyrin derivative and visible light. The results suggest that there is a relatively uniform cytotoxicity of human brain tumors with hematoporphyrin derivative at dose levels obtainable in clinical practice.

Influence of light delivery on photodynamic synovectomy in an antigen- induced arthritis model for rheumatoid arthritis

Minimally invasive synovectomy techniques have been unsuccessful due to lack of selectivity. The purpose of this study was to evaluate the potential of photodynamic therapy to destroy diseased synovium in an antigen‐induced arthritis model.

CATIONIC PHOTOIMMUNOCONJUGATES BETWEEN MONOCLONAL ANTIBODIES AND HEMATOPORPHYRIN : SELECTIVE PHOTODESTRUCTION OF OVARIAN CANCER CELLS

The photosensitizer hematoporphyrin (HP) was site specifically attached to a murine monoclonal antibody (MAb) fragment OC125F(ab?)(2) directed against ovarian cancer cells and to nonspecific rabbit immunoglobulin G. The photoimmunoconjugates were positively charged and were purified by column chromatography. The OC125F(ab?)(2) conjugate retained immunoreactivity with human ovarian cancer cells, and the binding was competed with unmodified MAb. Phototoxicity paralleled the cellular uptake with the OC125F(ab?)(2) conjugate and the light showing selective killing of target cells compared with nontarget cells. Nontargeted conjugates and free HP produced lower levels of phototoxicity and showed no selectivity.

The angiogenesis inhibitor NM-3 is active against human NSCLC xenografts alone and in combination with docetaxel

The novel isocoumarin 2-(8-hydroxy-6-methoxy-1-oxo-1 H-2-benzopyran-3-yl) propionic acid (NM-3) has completed phase I clinical evaluation as an orally bioavailable angiogenesis inhibitor. NM-3 directly kills both endothelial and tumor cells in vitro at low mM concentrations and is effective in the treatment of diverse human tumor xenografts in mice. The present work has assessed the activity of NM-3 against human non-small-cell lung cancer (NSCLC) cells when used alone and in combination with docetaxel. The results demonstrate that NM-3 decreases clonogenic survival of NSCLC cells at clinically achievable concentrations. The results also demonstrate that NM-3 is effective in the treatment of NSCLC (A549, NCI-H460) tumor xenografts in mice. Moreover, NM-3 potentiated the antitumor activity of docetaxel against NSCLC xenografts without increasing toxicity. Our findings indicate that NM-3 may be effective alone or in combination with docetaxel in the treatment of patients with NSCLC.

Spectroscopic determination of skin viability. A predictor of postmortem interval.

We have demonstrated that skin viability decreases at a measurable rate following death in an animal model. The decreased skin viability was measured by fluorescein diacetate and ethidium bromide using fluorescence emission spectroscopy. There is significant decrease of the fluorescence intensity of the fluorescein diacetate assay between the 1-4 h, the 6-24 h, and the >40 h time points postmortem. For times between 6-24 h and >40 h postmortem the ethidium bromide assay showed consistent and significant increases in signal. The fluorescence measurements in this study showed that under the experimental conditions the time of death could be determined for <4, 6-24, and >40 hapotmotrem. The application of these assays in the field will require further study of the environmental factors.