RESUMO
Peptide triazole thiols (PTTs) have been found previously to bind to HIV-1 Env spike gp120 and cause irreversible virus inactivation by shedding gp120 and lytically releasing luminal capsid protein p24. Since the virions remain visually intact, lysis appears to occur via limited membrane destabilization. To better understand the PTT-triggered membrane transformation involved, we investigated the role of envelope cholesterol on p24 release by measuring the effect of cholesterol depletion using methyl beta-cyclodextrin (MßCD). An unexpected bell-shaped response of PTT-induced lysis to [MßCD] was observed, involving lysis enhancement at low [MßCD] vs loss of function at high [MßCD]. The impact of cholesterol depletion on PTT-induced lysis was reversed by adding exogenous cholesterol and other sterols that support membrane rafts, while sterols that do not support rafts induced only limited reversal. Cholesterol depletion appears to cause a reduced energy barrier to lysis as judged by decreased temperature dependence with MßCD. Enhancement/replenishment responses to [MßCD] also were observed for HIV-1 infectivity, consistent with a similar energy barrier effect in the membrane transformation of virus cell fusion. Overall, the results argue that cholesterol in the HIV-1 envelope is important for balancing virus stability and membrane transformation, and that partial depletion, while increasing infectivity, also makes the virus more fragile. The results also reinforce the argument that the lytic inactivation and infectivity processes are mechanistically related and that membrane transformations occurring during lysis can provide an experimental window to investigate membrane and protein factors important for HIV-1 cell entry.
Assuntos
Colesterol/metabolismo , HIV-1/fisiologia , Lipídeos de Membrana/metabolismo , Linhagem Celular Tumoral , Proteína do Núcleo p24 do HIV/metabolismo , Proteína gp120 do Envelope de HIV/metabolismo , HIV-1/efeitos dos fármacos , HIV-1/patogenicidade , Humanos , Fluidez de Membrana , Peptídeos/química , Peptídeos/farmacologia , Compostos de Sulfidrila/química , Compostos de Sulfidrila/farmacologia , Tiazóis/química , Tiazóis/farmacologia , Triazóis/química , Triazóis/farmacologia , beta-Ciclodextrinas/farmacologiaRESUMO
Wound size reduction has been the standard benchmark for determination of efficacy for diabetic ulcer treatments but due to interclinician error and difficulty measuring irregular wound shapes, this method is unreliable with a positive predictive value of less than 60%. Diffuse near-infrared spectroscopy (DNIRS) uses 70-MHz modulated light in the diagnostic window (650-900 nm) noninvasively to quantify levels of oxy- and deoxy-hemoglobin in the wound bed, which when measured over time, can show a trend toward or away from healing based on the changes in oxy-hemoglobin concentration from week to week. In this study, DNIRS was used to monitor 24 human diabetic foot ulcers longitudinally over the course of 20 weekly or biweekly measurement sessions. In just 4 weeks, the DNIRS system has an 82% positive predictive value (sensitivity of 0.9 and specificity of 0.86; p < 0.002). These data indicate that it could be possible to predict healing in 4 weeks using DNIRS, which can provide objective guidance toward the continuation of costly treatments. Discontinuing ineffective treatments after 4 weeks could have potentially saved over $12,600 per patient, based on the treatment regimen of patients in this study.
Assuntos
Pé Diabético/patologia , Pé Diabético/fisiopatologia , Espectroscopia de Luz Próxima ao Infravermelho/economia , Cicatrização , Pé Diabético/economia , Feminino , Custos de Cuidados de Saúde , Humanos , Masculino , Microcirculação , Seleção de Pacientes , Philadelphia , Valor Preditivo dos Testes , Curva ROCRESUMO
We used the Maxwell stress tensor method to understand dielectrophoretic particle-particle interactions and applied the results to the interpretation of particle behaviors under alternating current (AC) electrohydrodynamic conditions such as AC electroosmosis (ACEO) and electrothermal flow (ETF). Distinct particle behaviors were observed under ACEO and ETF. Diverse particle-particle interactions observed in experiments such as particle clustering, particles keeping a certain distance from each other, chain and disc formation and their rotation, are explained based on the numerical simulation data. The improved understanding of particle behaviors in AC electrohydrodynamic flows presented here will enable researchers to design better particle manipulation strategies for lab-on-a-chip applications.
Assuntos
Eletroforese/métodos , Técnicas Analíticas Microfluídicas/métodos , Eletricidade , Eletro-Osmose , Modelos TeóricosAssuntos
Proteína gp120 do Envelope de HIV/antagonistas & inibidores , HIV-1/efeitos dos fármacos , HIV-1/metabolismo , Peptídeos/química , Triazóis/química , Triazóis/farmacologia , Sequência de Aminoácidos , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Linhagem Celular Tumoral , Ouro/química , Proteína do Núcleo p24 do HIV/metabolismo , Proteína gp120 do Envelope de HIV/metabolismo , Humanos , Nanopartículas Metálicas/químicaRESUMO
Glass micropipettes, atomic force microscope tips and nanoneedles can be used to interrogate cells, but these devices either have conical geometries that can damage cells during penetration or are incapable of continuous fluid handling. Here, we report a carbon-nanotube-based endoscope for interrogating cells, transporting fluids and performing optical and electrochemical diagnostics at the single organelle level. The endoscope, which is made by placing a multiwalled carbon nanotube (length, 50-60 µm) at the tip of a glass pipette, can probe the intracellular environment with a spatial resolution of â¼100 nm and can also access organelles without disrupting the cell. When the nanotube is filled with magnetic nanoparticles, the endoscope can be remotely manoeuvered to transport nanoparticles and attolitre volumes of fluids to and from precise locations. Because they are mounted on conventional glass micropipettes, the endoscopes readily fit standard instruments, creating a broad range of opportunities for minimally invasive intracellular probing, drug delivery and single-cell surgery.
Assuntos
Técnicas Eletroquímicas , Microscopia de Força Atômica/instrumentação , Nanotubos de Carbono , Células HeLa , Humanos , Microscopia Eletrônica de VarreduraRESUMO
Current influenza virus vaccines primarily elicit antibodies and can be rendered ineffective by antigenic drift and shift. Vaccines that elicit CD8+ T cell responses targeting less variable proteins may function as universal vaccines that have broad reactivity against different influenza virus strains. To generate such a universal vaccine, we encapsulated live influenza virus in a biopolymer and delivered it to mice subcutaneously. This vaccine was safe, induced potent CD8+ T cell immunity and protected mice against heterosubtypic lethal challenge. Safety of subcutaneous (SQ) vaccination was tested in Rag-/-γc-/- double knockout mice which we show cannot control intranasal infection. Biopolymer encapsulation of live influenza virus could be used to develop universal CD8+ T cell vaccines against heterosubtypic and pandemic strains.
Assuntos
Biopolímeros/administração & dosagem , Portadores de Fármacos/administração & dosagem , Vacinas contra Influenza/imunologia , Orthomyxoviridae/imunologia , Linfócitos T/imunologia , Animais , Modelos Animais de Doenças , Feminino , Proteínas Fetais , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/efeitos adversos , Injeções Subcutâneas , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infecções por Orthomyxoviridae/prevenção & controle , Proteínas com Domínio T , VacinasRESUMO
BACKGROUND: The efficacy of using diffuse near infrared spectroscopy (NIRS) in predicting wound healing in diabetic foot ulcers was demonstrated by conducting a pilot human study. METHOD: Sixteen chronic diabetic wounds were followed and assessed for subsurface oxyhemoglobin concentration using the NIRS device. Weekly measurements were conducted until there was wound closure, limb amputation, or 20 completed visits without healing. Wound size and degree of wound contraction were measured by image analysis of digital photographs, and results were compared to NIRS results. RESULTS: In the 16 patients followed, seven wounds healed, six limbs were amputated, and three wounds remained opened after 20 visits. Initial values of subsurface hemoglobin concentration, in all wounds, were higher than in nonwound control sites. Healed wounds exhibited a consistent reduction of hemoglobin concentration several weeks prior to closure, and the absolute hemoglobin concentration approached the value at the control site. In wounds that did not heal or ended in amputations, the hemoglobin concentration remained elevated throughout the study. A negative slope for the rate of change of hemoglobin concentration was indicative of healing across all wounds. CONCLUSIONS: Evaluation of diabetic foot ulcers using NIRS may provide an effective and more complete measurement of wound healing compared to current clinical approaches.
Assuntos
Pé Diabético/patologia , Monitorização Ambulatorial/instrumentação , Adulto , Idoso , Amputação Cirúrgica , Pé Diabético/cirurgia , Feminino , Hemoglobinas/análise , Hemoglobinas/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Oxiemoglobinas/análise , Projetos Piloto , Valor Preditivo dos Testes , Espectroscopia de Luz Próxima ao Infravermelho , Cicatrização/fisiologiaRESUMO
Progress in wound healing is primarily quantified by the rate of change of the wound's surface area. The most recent guidelines of the Wound Healing Society suggest that a reduction in wound size of <40% within 4 weeks necessitates a reevaluation of the treatment. However, accurate measurement of wound size is challenging due to the complexity of a chronic wound, the variable lighting conditions of examination rooms, and the time constraints of a busy clinical practice. In this paper, we present our methodology to quantify a wound boundary and measure the enclosed wound area reproducibly. The method derives from a combination of color-based image analysis algorithms, and our results are validated with wounds in animal models and human wounds of diverse patients. Images were taken by an inexpensive digital camera under variable lighting conditions. Approximately 100 patient images and 50 animal images were analyzed and a high overlap was achieved between the manual tracings and the calculated wound area by our method in both groups. The simplicity of our method combined with its robustness suggests that it can be a valuable tool in clinical wound evaluations. The basic challenge of our method is in deep wounds with very small surface areas where color-based detection can lead to erroneous results and which could be overcome by texture-based detection methods. The authors are willing to provide the developed MATLAB code for the work discussed in this paper.
Assuntos
Algoritmos , Superfície Corporal , Pé Diabético/patologia , Processamento de Imagem Assistida por Computador/métodos , Fotografação/métodos , Adulto , Idoso , Animais , Doença Crônica , Cor , Diabetes Mellitus Experimental/patologia , Pé Diabético/terapia , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ratos , Ratos Sprague-Dawley , Sensibilidade e Especificidade , Fatores de Tempo , Resultado do Tratamento , CicatrizaçãoRESUMO
A human study was conducted in which the efficacy of in vivo diffuse near-infrared (NIR) spectroscopy was demonstrated in predicting wound healing in diabetic foot ulcers. Sixteen chronic diabetic wounds were followed and assessed for subsurface oxy-hemoglobin concentration using the NIR device. Weekly measurements were conducted until there was wound closure, limb amputation, or 20 completed visits without healing. Digital photography measured wound size, and the degree of wound contraction was compared with the NIR results. In the 16 patients followed, seven wounds healed, six limbs were amputated, and three wounds remained opened after 20 visits. The initial values in subsurface hemoglobin concentration in all wounds were higher than the nonwound control sites. Healed wounds showed a consistent reduction of hemoglobin concentration several weeks before closure that approached control site values. In wounds that did not heal or resulted in amputation of the limb, the hemoglobin concentration remained elevated. In some cases, these nonhealing wounds appeared to be improving clinically. A negative slope for the rate of change of hemoglobin concentration was indicative of healing across all wounds. In conclusion, evaluation of wounds using NIR may provide an effective measurement of wound healing. NIR spectroscopy can determine wound healing earlier than that visibly assessed by current clinical approaches.
Assuntos
Pé Diabético/patologia , Pé Diabético/terapia , Espectroscopia de Luz Próxima ao Infravermelho , Adulto , Idoso , Amputação Cirúrgica , Pé Diabético/metabolismo , Hemoglobinas/metabolismo , Humanos , Pessoa de Meia-Idade , Projetos PilotoRESUMO
Acute exposure to UV radiation (UVR) causes visible skin damage such as erythema and results in local and systemic immunosuppression while chronic exposure can result in photocarcinogenesis. These deleterious effects can be quantified by histology and by bioassays of key biological markers, including matrix metalloproteinases (MMPs), or tryptophan moieties. We now report our results in quantifying UV skin damage with noninvasive optical methods based on reflectance and fluorescence spectroscopy and compare these noninvasive measurements to histopathology and MMP-13 expression. A solar simulator with spectral output nearly identical to that of solar radiation was developed and used in our experiments. SKH1 hairless mice were exposed to solar-simulated UVR at a total dose of 21 MED delivered over 10 weeks. Changes in oxygenated and deoxygenated hemoglobin were measured by diffuse reflectance spectroscopy, and tryptophan changes were monitored via a fluorescence monitor. Our results show that there is an increase in erythema, skin fluorescence, sunburn cells and MMP-13 after a series of suberythemal doses of UV irradiation on a hairless mouse animal model. Increased skin fluorescence is observed with increasing UV exposure. The levels of MMP-13 increase as the cumulative UV dose increases but their increase does not correspond to noninvasively measured changes.
Assuntos
Envelhecimento da Pele/efeitos da radiação , Raios Ultravioleta/efeitos adversos , Animais , Biomarcadores/análise , Eritema , Metaloproteinase 13 da Matriz/análise , Metaloproteinases da Matriz/análise , Camundongos , Camundongos Pelados , Espectrometria de Fluorescência , TriptofanoRESUMO
BACKGROUND/PURPOSE: The ability to optically section live biological tissue in vivo with laser light is made possible by confocal laser scanning microscopy (CLSM). In this work, the effects of changing the wavelength of incident light used for CLSM imaging of human skin are reported and analyzed. METHODS: Optical phantoms and the skin of eight human volunteers were imaged using CLSM systems having three different incident light wavelengths (405, 785, and 830 nm). RESULTS: Qualitative and quantitative differences were observed between images obtained at each wavelength, despite the proximity of the two near infrared 785 and 830 nm wavelengths. Furthermore, the penetration depth achieved with the 405 nm CLSM permitted imaging into the papillary dermis. CONCLUSION: The laser wavelength used in CLSM reflectance imaging is important to properly understand and resolve different biological structures within human skin.
Assuntos
Dermoscopia/instrumentação , Dermoscopia/métodos , Microscopia Confocal/instrumentação , Microscopia Confocal/métodos , Pele/citologia , Adulto , Artefatos , Derme/citologia , Células Epidérmicas , Feminino , Folículo Piloso/citologia , Humanos , Lasers , Luz , Pessoa de Meia-Idade , Imagens de FantasmasRESUMO
The development of a simple and inexpensive quantum dot based immunoassay for detecting myeloperoxidase (MPO) in stool samples is reported (QLISA). The method developed utilizes readily available polymethylmethacrylate (PMMA) microcapillaries as substrates for performing the sandwich assay. High power (80 mW) and low power (10 mW) UV-LEDs were tested for their efficiency in maximizing detection sensitivity in a waveguide illumination or a side illumination mode. The results obtained indicate that both waveguide and side illumination modes can be employed for detecting MPO down to 15 ng/mL, however the high power LED in a side illumination mode improves sensitivity and simplifies the data acquisition process. The protocol and sensor robustness was evaluated with animal stool samples spiked with MPO and the results indicate that the sensitivity of detection is not compromised when used in stool samples. The effect of the ionic strength of the environment on the fluorescence stability of quantum dots was evaluated and found to affect the assay only if long imaging times are employed. Replacing the buffer with glycerol during imaging increased the fluorescence intensity of quantum dots while significantly minimized the loss in intensity even after 2h.
Assuntos
Técnicas Biossensoriais/instrumentação , Ensaio de Imunoadsorção Enzimática/instrumentação , Fezes/química , Peroxidase/análise , Polimetil Metacrilato/química , Pontos Quânticos , Espectrometria de Fluorescência/instrumentação , Animais , Ação Capilar , Desenho de Equipamento , Análise de Falha de Equipamento , Miniaturização , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
A pilot human study is conducted to evaluate the potential of using diffuse photon density wave (DPDW) methodology at near-infrared (NIR) wavelengths (685 to 830 nm) to monitor changes in tissue hemoglobin concentration in diabetic foot ulcers. Hemoglobin concentration is measured by DPDW in 12 human wounds for a period ranging from 10 to 61 weeks. In all wounds that healed completely, gradual decreases in optical absorption coefficient, oxygenated hemoglobin concentration, and total hemoglobin concentration are observed between the first and last measurements. In nonhealing wounds, the rates of change of these properties are nearly zero or slightly positive, and a statistically significant difference (p<0.05) is observed in the rates of change between healing and nonhealing wounds. Differences in the variability of DPDW measurements over time are observed between healing and nonhealing wounds, and this variance may also be a useful indicator of nonhealing wounds. Our results demonstrate that DPDW methodology with a frequency domain NIR device can differentiate healing from nonhealing diabetic foot ulcers, and indicate that it may have clinical utility in the evaluation of wound healing potential.
Assuntos
Pé Diabético/diagnóstico , Pé Diabético/fisiopatologia , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Cicatrização/fisiologia , Absorção , Adolescente , Adulto , Idoso , Análise de Variância , Diabetes Mellitus/metabolismo , Diabetes Mellitus/patologia , Pé Diabético/metabolismo , Hemoglobinas/metabolismo , Humanos , Pessoa de Meia-Idade , Oxiemoglobinas/metabolismo , Projetos Piloto , Valor Preditivo dos TestesRESUMO
This study reports the effect of liposome particle size at the nanoscale and bilayer deformability on the permeation through MatTek human skin equivalents and provides a comparative quantitative measure through calculation of diffusion coefficients. Exploring DOPC and DPPC fluorescent liposomes, our results demonstrate the faster diffusion of 50 nm liposomes compared with 100 and 200 nm liposomes when the lipid bilayer remains the same. Diffusion kinetics of the 50 nm particles appear not to depend on the rigidity of the lipid layer, whereas diffusion of particles larger than 100 nm is significantly affected by the rigidity of the bilayer, and DOPC liposomes diffuse faster than their DDPC equivalents. Our results suggest that liposomes composed of a rigid bilayer can be expected to remain intact after passing through the stratum corneum.
Assuntos
Lipossomos/química , Lipossomos/farmacocinética , Tamanho da Partícula , Pele/metabolismo , 1,2-Dipalmitoilfosfatidilcolina/química , 1,2-Dipalmitoilfosfatidilcolina/farmacocinética , Difusão , Humanos , Fosfatidilcolinas/química , Fosfatidilcolinas/farmacocinéticaRESUMO
Changes of optical properties of wound tissue in hairless rats were quantified by diffuse photon density wave methodology at near-infrared frequencies. The diffusion equation for semi-infinite media was used to calculate the absorption and scattering coefficients based on measurements of phase and amplitude with a frequency domain device. There was an increase in the absorption and scattering coefficients and a decrease in blood saturation of the wounds compared with the nonwounded sites. The changes correlated with the healing stage of the wound. The data obtained were supported by immunohistochemical analysis of wound tissue. These results verified now by two independent animal studies could suggest a noninvasive method to detect the progress of wound healing.
Assuntos
Modelos Animais de Doenças , Refratometria/métodos , Pele/lesões , Pele/fisiopatologia , Análise Espectral/métodos , Cicatrização/fisiologia , Ferimentos Penetrantes/fisiopatologia , Animais , Feminino , Luz , Ratos , Ratos Pelados , Ratos Sprague-Dawley , Espalhamento de RadiaçãoRESUMO
Monoclonal antibodies (mAbs) that inhibit activation of the epidermal growth factor receptor (EGFR) have shown therapeutic potential in select malignancies including breast cancer. Here, we describe that combined use of two such mAbs, C225 (Cetuximab) and 425 (EMD55900), reduced growth and survival of EGFR overexpressing MDA-MB-468 breast cancer cells more effectively than either antibody alone. Similarly, the C225/425 antibody combination more effectively inhibited AKT and MAPK phosphorylation in MDA-MB-468 cells. Surface plasmon resonance, size exclusion chromatography and analytical ultracentrifugation demonstrated that mAbs C225 and 425 simultaneously bind to distinct antigenic epitopes on domain III of the soluble wild-type EGFR. Furthermore, neither mAb competed with the other for binding to cells expressing either wild-type EGFR or a mutant EGFR (EGFRvIII) associated with neoplasia. Mutagenesis experiments revealed that residues S460/G461 in EGFR domain III are essential components of the 425 epitope and clearly distinguish it from the EGF/ TGFalpha binding site and the C225 interaction interface. Collectively, these results support the conclusion that therapeutic EGFR blockade in cancer patients by combined use of mAbs C225 and 425 could provide advantages over the use of the two antibodies as single agents.
Assuntos
Anticorpos Monoclonais/química , Epitopos , Receptores ErbB/antagonistas & inibidores , Animais , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais Humanizados , Linhagem Celular Tumoral , Cetuximab , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Mapeamento de Epitopos , Epitopos/química , Humanos , Camundongos , Conformação Molecular , Células NIH 3T3 , Tirfostinas/farmacologiaRESUMO
The objective of this paper was to correlate optical changes of tissue during wound healing measured by near infrared (NIR) and diffuse reflectance spectroscopy (DRS) with histologic changes in an animal model. Amplitude and phase of scattered light were obtained in a diabetic rat and control model and biopsies were taken for blood vessel ingrowth and collagen concentration. NIR absorption coefficient correlated with blood vessel ingrowth over time, in both the control and diabetic animals. DRS data correlated with collagen concentration. Previous publications by this group documented only the NIR changes during the wound healing process but this is the first reported correlation with histology data. The ability to correlate DRS scattering with collagen concentration during healing is another important and novel finding. This technology may play an important role clinically in assessing the efficacy of wound healing agents in diabetics.
Assuntos
Colágeno/metabolismo , Diabetes Mellitus Experimental/fisiopatologia , Neovascularização Fisiológica/efeitos dos fármacos , Espectroscopia de Luz Próxima ao Infravermelho , Cicatrização , Animais , Contagem de Células , Feminino , Técnicas Histológicas , Ratos , Ratos Pelados , Ratos Sprague-Dawley , Espalhamento de Radiação , Pele/irrigação sanguínea , Pele/metabolismo , Pele/patologia , Espectrofotometria , Cicatrização/fisiologiaRESUMO
A frequency domain diffuse optical tomography instrument operating in the Near Infrared region (680-830nm) has been designed and used to monitor healing in diabetic wounds in a rat animal model. Instrument design and calibration are described and preliminary data of the in vivo experiment are reported. Excellent discrimination capability between the control and the diabetic population is possible, while the time course of impaired healing in diabetic animals appears to have different optical coefficients from the normal healing in the control group.
Assuntos
Diabetes Mellitus , Espectroscopia de Luz Próxima ao Infravermelho , Tomografia Óptica/instrumentação , Cicatrização , Animais , Doença Crônica , Modelos Animais , Monitorização Fisiológica/instrumentação , Qualidade da Assistência à Saúde , RatosRESUMO
Measurement of scattering and absorption characteristics of tissue by near infrared spectroscopy may provide a clinically applicable, quantitative method of assessing healing of diabetic wounds. Twenty SICH-1 hairless rats were divided into a control group and a streptozotocin-induced diabetic group. Full-thickness wounds were made on the dorsal surface of each animal. Wounds were examined using a near infrared device with three wavelengths of incident light. Amplitude and phase of scattered light were obtained at four different source detector distances at each wavelength. The probe was positioned at six different locations. Tissue absorption and scattering coefficients were calculated from amplitude and phase data. Wound dimensions were calculated by cross and parallel polarization. Thirty-eight wounds were evaluated during the experiment. Wound size decreased at twice the rate in the control animals, whereas the average absorption coefficient was higher by a factor of two while the average value of the reduced scattering coefficient was 30% higher in the diabetic wounds. During healing, both scattering and absorption coefficients increased faster in the diabetics. Higher absorption in diabetic rats suggests impaired blood flow. Scattering may reflect tissue disorganization observed in delayed wound healing. We conclude that near infrared spectroscopy may differentiate between healing diabetic and nondiabetic wounds.
Assuntos
Diabetes Mellitus Experimental/fisiopatologia , Pele/lesões , Cicatrização , Animais , Feminino , Ratos , Ratos Nus , Espectroscopia de Luz Próxima ao InfravermelhoRESUMO
Diffuse photon density wave (DPDW) methodology at Near Infrared frequencies has been used to calculate absorption and scattering from wounds of healthy and diabetic rats. The diffusion equation for semi-infinite media is being used for calculating the absorption and scattering coefficients based on measurements of phase and amplitude with a frequency domain device. Differences observed during the course of healing in the two populations can be correlated to the delayed healing observed in diabetics. These results are encouraging and further work will focus on the implementation of this device to the clinical setting as a monitoring tool in chronic diabetic wounds.