Association of the ACE rs4646994 and rs4341 polymorphisms with the progression of carotid atherosclerosis in slovenian patients with type 2 diabetes mellitus.

The current study was designed to reveal possible associations between the angiotensin-converting-enzyme (ACE) gene polymorphisms (rs4646994 and rs4341) with markers of carotid atherosclerosis in patients with type 2 diabetes mellitus (T2DM) in a 4-year-long follow-up study. Five hundred and ninety-five T2DM subjects and 200 control subjects were enrolled. Genotyping of ACE polymorphisms was performed using KASPar assays, and ultrasound examinations were performed twice (at the enrollment and at follow-up). With regard to the progression of atherosclerosis in subjects with T2DM, statistically significant differences were demonstrated in the change of the sum of carotid plaques thickness for the rs4646994 polymorphism. We did not demonstrate an association between the tested polymorphisms (rs4646994 and rs4341) and either carotid intima media thickness (CIMT) or CIMT progression in a 3.8-year period. In our study, we demonstrated that subjects with T2DM with the DD genotype of the rs4646994 [ACE insertion/deletion (I/D)] polymorphism had faster progression of atherosclerosis in comparison to subjects with other genotypes.

Optofluidic microsystems with integrated vertical one-dimensional photonic crystals for chemical analysis.

In this work, we report all-silicon, integrated optofluidic microsystems (OFMs) fabricated by electrochemical micromachining (ECM) technology, in which high aspect-ratio (HAR) photonic crystal (PhC) devices (i.e. micromirrors, optical cavities) are integrated by one-etching-step, together with microfluidic reservoirs/channels, for the infiltration of liquids in the PhC air gaps, and with fiber grooves for alignment/positioning of readout optical fibers in front of the PhC, on the same silicon die. This has not previously been reported in the literature, and opens up new ground in, though not limited to, the optofluidics field, due to the low-cost and high-flexibility of the ECM technology that allows optofluidic microsystem fabrication to be performed in any lab. Optofluidic characterization of PhC-OFMs by both capillary-action and pressure-driven operations is carried out through the measurement of the reflectivity spectra of HAR-PhCs upon injection of liquids featuring different refractive index values in the HAR-PhC air gaps, by using readout optical fibers positioned in the on-chip fiber grooves. High sensitivity and good limit of detection of PhC-OFMs are obtained for both capillary-action and pressure-driven operations. A best sensitivity value of 670 nm/RIU and a worst-case limit of detection of the order of 10(-3) RIU are measured, the former being comparable to state-of-the-art integrated refractive index sensors and the latter being limited by constraints of the experimental setup. The proof of concept about the biosensing potential of PhC-OFMs is given by successfully carrying out a sandwich assay based on antigen-antibody interactions for the detection of the C-reactive protein (CRP) at a concentration value of 10 mg L(-1), which represents the boundary level between physiological and pathological conditions.

New targets for antibacterial design: Kdo biosynthesis and LPS machinery transport to the cell surface.

Lipopolysaccharide (LPS), which constitutes the lipid portion of the outer leaflet of Gram-negative bacteria, is essential for growth. It is also responsible for the variety of biological effects associated with Gram-negative sepsis. Recent advances have elucidated the exact chemical structure of this highly complex macromolecule and much of the enzymology involved in its biosynthesis. Enzymes involved in LPS biogenesis are optimal targets for the development of novel therapeutics since they are sufficiently conserved among diverse, clinically-relevant bacteria and no analogue counterpart is present in humans. During the last thirty years a number of inhibitors of LPS biosynthesis have been developed: some of these compounds have antibacterial properties, while others show excellent in vitro activity and are undergoing further investigation. The main focus of this review will be the biology of LPS in bacteria summarizing the knowledge about structure and enzymatic catalysis, as well as chemical efforts towards the synthesis of inhibitors of the key enzymes involved in the biosynthesis of Kdo, toward the minimal conserve structure Kdo(2)-LipA. In addition, very recent advances in deciphering the molecular mechanisms of LPS transport to the cell surface, as a new target to develop novel antibacterials, will be reported. Future directions and perspectives will also be outlined.

Glia mediates the neuroprotective action of estradiol on beta-amyloid-induced neuronal death.

17beta-Estradiol (17beta-E(2)) is known to exert neuroprotective activity against beta-amyloid, but its exact target and mechanism of action in this effect have not been elucidated. The involvement of astroglia in neuroprotection of 17beta-E(2) against the beta-amyloid fragment [betaAP((25-35))] has been evaluated using an experimental paradigm in which medium conditioned from rat astroglia pretreated with 17beta-E2 was transferred to pure rat cortical neurons challenged with 25 microm betaAP((25-35)) for 24 h. The toxicity of betaAP((25-35)) was assessed by flow cytometry, evaluating the ability of the peptide to induce an aberrant mitotic cell cycle in neurons. The results obtained indicate that conditioned medium from astrocytes preexposed to 17beta-E(2) for 4 h increased the viability of cortical neurons treated with betaAP((25-35)). This effect was not modified by treatment with the estrogen receptor antagonist ICI 182,780, added directly to neurons, nor was it mimicked by direct addition of 17beta-E(2) to neuronal cultures during exposure to betaAP((25-35)). A soluble factor stimulated by 17beta-E(2) seemed to be involved, and accordingly, the intracellular and released levels of TGF-beta1 were increased by 17beta-E(2) treatment, as established by Western blot analysis. In addition, the intracellular content of TGF-beta1 in immunopositive cells, as detected by flow cytometry, was reduced, suggesting that 17beta-E(2) stimulated mainly the release of the cytokine. In support of a role for TGF-beta1 in astrocyte-mediated 17beta-E(2) neuroprotective activity, incubation with a neutralizing anti-TGF-beta1 antibody significantly modified the reduction of neuronal death induced by 17beta-E(2)-treated astrocyte-conditioned medium.

Intraocular pressure and progression of visual field damage.

Contradicting results concerning IOP control and visual field deterioration are presented. Some of these inconsistencies may be due to the statistical method of analysis. Sixty POAG patients with a perimetric follow-up over 3 years were selected. Mean and maximum IOPs were considered during the same period. The patients were divided into two groups according to the IOP control (well controlled or poorly controlled). Visual field progression was defined as a reduction in sensitivity over the fifth percentile in more than four points. Mean IOPs were not significantly different in the group of patients with a visual field deterioration compared to the stable ones, but the percentage of patients with a visual field deterioration was significantly higher in patients with higher IOPs. This holds especially true if IOP below 16 mmHg (G) is considered the 'target pressure'. IOP reduction seems to play an essential role in visual field progression. In glaucomatous patients, a strict (<16 mmHg (G)) might be necessary.

Valores de referencia de leptina obtenidos en donantes de sangre y su relación con marcadores nutricionales / Referente values for leptin obtained from blood Donors and its relation with nutricional markers

Objetivo: La leptina, el producto del gen ob, es una proteína que actúa en el cerebro induciendo la saciedad, el control de la ingesta alimenticia y el peso corporal. El propósito de este estudio es obtener los valores de referencia de leptina en suero en adultos sanos, de acuerdo a su Índice de Masa Corporal (IMC) y determinar la relación entre leptina y algunos marcadores nutricionales. Material y métodos: La leptina fue medida por enzimoinmunoanálisis con el estuche analítico de SDL en 254 donantes de sangre. Las concentraciones de glucosa, colesterol y triglicérido fueron determinadas en un Hitachi 747, mientras que las de ferritina, folato y cobalamina se obtuvieron por quimiolumniniscencia en un Immulite 2000. Resultados: Los intervalos de referencia, obtenidos de acuerdo al Panel de Expertos de la IFCC, fueron 2,1-10,9ug/l y 2,9-38,5 ug/l en hombres y mujeres, respectivamente. Las concentraciones de leptina aumentan conforme se incrementa el IMC. La leptina se correlacionó con el peso corporal y con el IMC en hombres (r=0,50 y r=0,55, respectivamente, p<0,001) y en mujeres (r=0,6 y r=0,69, p<0,001, respectivamente). En mujeres la leptina cambió con el ciclo menstrual. Encontramos correlaciones significativas entre la leptina y la edad, la glucosa, la ferritina, la cobalamina, la insulina y la razón insulina/glucosa. Conclusiones: La concentración de leptina en suero depende del sexo y del IMC. Por otra parte, con el estuche analítico ELISA de DSL se obtienen concentraciones más altas de leptina en individuos sanos que las aparecidas en la bibliografía (AU)

Anticuerpo antitransglutaminasa: utilidad en el diagnóstico de la enfermedad celíaca / The tissue transglutaminase antibody: usefulness in the diagnosis of celiac disease

OBJETIVO: Hasta ahora los anticuerpos de clase IgA antiendomisio (AEmIgA) y antigliadina (AAGIgA) se consideraban unos marcadores sensibles y específicos de enfermedad celíaca. Recientemente se ha identificado un nuevo anticuerpo, el antitransglutaminasa (TGtIgA), como un marcador si no mejor, sí más práctico en el cribado de dicha enfermedad, sobre todo como una prueba muy útil de detección en grandes poblaciones. El objetivo de este trabajo ha sido evaluar la utilidad del TGtIgA como prueba de diagnóstico y cribado de la enfermedad celíaca y observar la relación existente entre este anticuerpo y los otros más conocidos y sobradamente utilizados como el AAGIgA y el anticuerpo antiendomisio (AEmIgA). PACIENTES Y MÉTODOS: El estudio se ha realizado en 115 niños divididos en 3 grupos: 31 pacientes diagnosticados de enfermedad celíaca según los criterios de la ESPGAN, 21pacientes celíacos en fase de dieta libre de gluten y 63 considerados grupo control. Se emplearon dos métodos inmunoenzimáticos comerciales (ELISA para detectar los AAGIgA e IgA TGt, respectivamente. Los AEmIgA se cuantificaron mediante un método de fluorescencia indirecta utilizando porción distal de esófago de mono como antígeno. RESULTADOS: En el grupo global de 115 pacientes, el TGtIgA presentó una concordancia del 91 por ciento con el AEmIgA y del 85 por ciento con el AAGIgA. Cuando el grupo estudiado era el de enfermos celíacos esta concordancia era del 84 y 61 por ciento, respectivamente. Por otra parte, el TGtIgA presentó una sensibilidad de 83 frente al 94 por ciento de los AEmIgA y el 74 por ciento de los AAGIgA. Los tres anticuerpos presentaron una especificidad similar.CONCLUSIÓN: El uso de un método ELISA para determinar los TGtIgA muestra una buena correlación con las determinaciones de AAG y AEm y podría representar una nueva prueba de detección en la enfermedad celíaca. La técnica es sencilla, presenta una buena especificidad y sensibilidad respecto a los clásicos AAG y AEm, no está sometida a la subjetividad de la persona que evalúa la prueba, es barata y muy práctica en programas de cribado generalizado. OBJETIVO: Hasta ahora los anticuerpos de clase IgA antiendomisio (AEmIgA) y antigliadina (AAGIgA) se consideraban unos marcadores sensibles y específicos de enfermedad celíaca. Recientemente se ha identificado un nuevo anticuerpo, el antitransglutaminasa (TGtIgA), como un marcador si no mejor, sí más práctico en el cribado de dicha enfermedad, sobre todo como una prueba muy útil de detección en grandes poblaciones. El objetivo de este trabajo ha sido evaluar la utilidad del TGtIgA como prueba de diagnóstico y cribado de la enfermedad celíaca y observar la relación existente entre este anticuerpo y los otros más conocidos y sobradamente utilizados como el AAGIgA y el anticuerpo antiendomisio (AEmIgA). PACIENTES Y MÉTODOS: El estudio se ha realizado en 115 niños divididos en 3 grupos: 31pacientes diagnosticados de enfermedad celíaca según los criterios de la ESPGAN, 21 pacientes celíacos en fase de dieta libre de gluten y 63 considerados grupo control. Se emplearon dos métodos inmunoenzimáticos comerciales (ELISA para detectar los AAGIgA e IgA TGt, respectivamente. Los AEmIgA se cuantificaron mediante un método de fluorescencia indirecta utilizando porción distal de esófago de mono como antígeno. RESULTADOS: En el grupo global de 115 pacientes, el TGtIgA presentó una concordancia del 91 por ciento con el AEmIgA y del 85 por ciento con el AAGIgA. Cuando el grupo estudiado era el de enfermos celíacos esta concordancia era del 84 y 61 por ciento, respectivamente. Por otra parte, el TGtIgA presentó una sensibilidad de 83 frente al 94 por ciento de los AEmIgA y el 74 por ciento de los AAGIgA. Los tres anticuerpos presentaron una especificidad similar. CONCLUSIÓN: El uso de un método ELISA para determinar los TGtIgA muestra una buena correlación con las determinaciones de AAG y AEm y podría representar una nueva prueba de detección en la enfermedad celíaca. La técnica es sencilla, presenta una buena especificidad y sensibilidad respecto a los clásicos AAG y AEm, no está sometida a la subjetividad de la persona que evalúa la prueba, es barata y muy práctica en programas de cribado generalizado (AU)

Comparison of two different methods for measurement of phenylalanine in dried blood spots.

Phenylketonuria is an inherited metabolic disorder caused by a defect in the hydroxylation of phenylalanine. Newborn screening is crucial for the diagnosis and treatment of this disease. A phenylalanine dehydrogenase-coupled enzymatic assay (Quantase) in microtiter plates for the screening of phenylketonuria was evaluated and compared with our routine method based on the modified fluorometric McCaman method. The test exhibited a linear calibration curve with a good slope as well as sufficient imprecision (< 10%), recovery (99.23+/-4.86%) and limit of detection (54.5 micromol/l). One hundred and ninety dried blood spots were analysed by this enzymatic method and compared with McCaman's. Although Quantase (Teknovas, Bilbao, Spain) showed a phenylalanine mean level in dried blood spot 18.2 micromol/l higher than that obtained with our routine method, the agreement between both techniques was considered acceptable.

Comparación de tres inmunoanálisis para la cuantificación de PSA, PSAL, CEA y Ca 15.3 / Comparison of three immunoassays for the measurement of PSA, FPSA, CEA and Ca 15.3

Objetivo: Comparar los resultados de varios marcadores tumorales obtenidos en los analizadores AxSym, Inmulite y Elecsys. Material y Métodos: Se han analizado varios sueros recibidos en nuestro Servicio de forma rutinaria para la cuantificación del antígeno específico de próstata (PSA), el antígeno específico de próstata libre (PSAL), el antígeno carcinoembrionario (CEA) y el antígeno reactivo con el anticuerpo monoclonal Ca 15.3 (Ca 15.3) mediante tres inmunoanálisis diferentes. Los resultados fueron evaluados estadísticamente mediante la aplicación de la línea de regresión estructural de la mediana absoluta de Feldmann y de las curvas de las diferencias descritas por Bland y Altman. Resultados: El grado de correlación según la estadística robusta de Feldmann es bueno para todos los marcadores y entre los analizadores objeto de valoración. Los valores de PSA, CEA y Ca 15.3 obtenidos en el analizador Immulite son más altos que aquellos procedentes del AxSym. Al comparar los analizadores AxSym/Elecsys, los resultados de PSA y Ca 15.3 fueron más altos en el AxSym. Conclusiones: los resultados de PSA y de CEA en los analizadores estudiados no se diferencian de forma significativa, no obstante existen diferencias reseñables en el caso del PSAL y del Ca 15.3 (AU)

Tripsinógeno 2 urinario como marcador bioquímico de pancreatitis aguda / Urinary trypsinogen-2 as biochemical marker of acute pancreatitis

Se ha evaluado la detección de tripsinógeno 2 urinario mediante tiras reactivas frente a la determinación de la actividad catalítica de a-amilasa plasmática y urinaria como método diagnóstico, de pancreatitis aguda. Se estudiaron 34 pacientes consospecha clínica de pancreatitis aguda. A todos ellos se les determinaron las actividades catalíticas a-amilasa plasmática y urinaria mediante el reactivo a-Amylae EPS (Roche diagnostics) en el autoanalizador Synchron CX7 (Beckman) y el tripsinógeno 2 urinario mediante tiras Dipsticks`` (Medix Biochemica). Para confirmar el diagnóstico se revisaron las historias clínicas de los pacientes. La prueba más sensible fue la aamilasa plasmática y la más específica la a-amilasa urinaria aunque ninguna de ellas fue significativamente mejor que la detección de tripsinógeno 2 en orina mediante tiras reactivas (Dipsticks). Por ello la utilización de dichas tiras para el diagnóstico de pancreatitis aguda está plenamente justificado cuando no se pueda determinar la a-amilasa de forma urgente (AU)

Medida de la composición fecal en niños celiacos mediante espectroscopía de reflectancia en el infrarrojo cercano / Measurement of stool composition in children with celiac disease using near-infrared reflectance spectroscopy

La enfermedad celiaca es una patología originada por la intolerancia al gluten y que cursa frecuentemente con un síndrome de malabsorción cuando se presenta en su forma clásica digestiva. El objetivo de este trabajo es evaluar en el momento del diagnóstico la composición de las heces de niños celiacos con síndrome de malabsorción, comparándola con la de niños sanos mediante un nuevo procedimiento analítico. Se han estudiado 30 niños celiacos diagnosticados mediante biopsia yeyunal y 86 niños control. El análisis de la composición fecal, agua, grasa, nitrógeno y azúcar, se realizó mediante espectroscopia de reflectancia en el infrarrojo cercano en heces de 24 horas. Los resultados muestran que los niños celiacos eliminan diariamente mayor cantidad de agua, grasa, nitrógeno y azúcar que los niños control. Esto puede ser debido no sólo a su condición de celiacos sino a la mayor eliminación en peso de heces. De todos los nutrientes, la grasa fecal es la sustancia que más se modifica, indicando que este nutriente sigue siendo el mejor parámetro fecal para el manejo de pacientes con síndrome de malabsorción. La espectroscopia de reflectancia en el infrarrojo cercano se perfila como una buena herramienta a la hora de conocer la eliminación fecal de los principales nutrientes (AU)

[Transglutaminase antibody: usefulness in the diagnosis of celiac disease]. / Anticuerpo antitransglutaminasa: utilidad en el diagnóstico de la enfermedad celíaca.

AIM: Until now IgA-EmA and IgA-AGA antibodies have been considered to be specific and sensitive markers of celiac disease. Anew antibody, the tissue transglutaminase (IgA-tTG), antibody has recently been identified, which is believed to be if not a better marker then a more practical one in screening for celiac disease, especially in large populations. To evaluate the usefulness of the IgA-tTG antibody in the diagnosis and screening of celiac disease and to determine the relationship between this antibody and other better known and over-used antibodies, antigliadin (IgA-AGA) and antiendomysial (IgA-EmA). PATIENTS AND METHODS: The study was performed in 115 children divided into three groups: 31 patients diagnosed with the celiac disease, according to the ESPGAN criteria; 21 patients with celiac disease following a gluten free diet, and 63 considered as control group. Two enzyme linked immunoabsorbent assays (ELISA) were used to detect AGA and tTG antibodies, respectively. EmA antibodies were determined by using an indirect immunofluorescence technique with commercial sections of distal monkey oesophagus as antigen. RESULTS: In the 115 patients taken as a whole, the tTG antibody showed 91% agreement with the EmA antibody and 85% agreement with the AGA antibody. In the celiac group, agreement was 84% and 61% respectively. Sensitivity of the tTG antibody was 83% compared with 94% for EmA and 74% for AGA. Specificity was similar in all three tests. CONCLUSIONS: The ELISA test for tTG correlates well with the traditional AGA and EmA tests and could be used as a new test for celiac disease. The procedure is simple and shows high specificity and sensitivity compared with classical EmA and AGA tests and does not involve subjective scoring. It is cheap and very well suited for large scale screening for celiac disease.

[Measurement of stool composition in children with celiac disease using near-infrared reflectance spectroscopy]. / Medida de la composición fecal en niños celiacos mediante espectroscopía de reflectancia en el infrarrojo cercano.

Celiac disease is a disorder caused by gluten-sensitivity which, when manifested in its classical digestive form, frequently presents a malabsorption syndrome. The aim of this study is to evaluate the faecal composition in celiac children with malabsorption syndrome at the moment of diagnosis by using near-infrared reflectance spectroscopy and to compare it with that of healthy children. Thirty children with biopsy-proven celiac disease and 86 age-matched control children were recruited in our study. Children collected 24 hour faecal specimens and the analyses of faeces, water, fat, nitrogen and sugar were performed using near-infrared reflectance spectroscopy. Results show that celiac children daily eliminate a significantly greater quantity of water, fat, nitrogen and sugar than those in the control group. This might be due to the higher weight of faeces eliminated in the celiac group and, of course, to their celiac condition. Of all the nutrients, faecal fat is the substance which undergoes the greatest change, indicating that this nutrient continues to be the best parameter for dealing with patients with malabsorption syndrome. Near-infrared reflectance spectroscopy appears to be a useful tool for assessing stool composition in celiac disease.

Water, fat, nitrogen, and sugar content in feces: reference intervals in children.

Malabsorption-maldigestion syndromes are commonly found in several gastrointestinal diseases. Quantitative measures of fecal nutrients are important tools for the detection and diagnosis of these syndromes. Adequate food intake is important in the nutrition of children, especially during the first year of life. We have analyzed 180 stools of healthy children, divided into four age groups, to obtain the reference intervals of the major nutrients such as water, fat, nitrogen, sugar, and starch. Quantification of the nutrients was done by means of a near-infrared analyzer (Fenir 8820). Results show that this instrument exhibits a low coefficient of variation for all the nutrients except for starch. Fecal water, fat, nitrogen, and sugar concentrations ranged from 68.7 to 96.1 g/100 g, 0 to 14.5 g/100 g, 1.3 to 2.3 g/100 g, and 0.7 to 3.8 g/100 g, respectively. The results for the starch analyses were not acceptable because of instrument limitations. Near-infrared reflectance spectroscopy appears to be an alternative to standard chemical methods.

Fast characterization of metal films for fiber attenuators.

We propose a new procedure for evaluating the complex refractive index of a metal film, based on transmission measurements at different incidence angles. The method is simpler and faster than standard ellipsometry and performs the accuracy required for the design of fiber-optic attenuators for telecommunications. As an example, we report on a device showing a constant attenuation on the 1200-1600-nm wavelength range.

[Deoxypyridinoline and other biochemical markers of bone resorption in distinct pathologies]. / Deoxipiridinolina y otros marcadores bioquímicos de reabsorción ósea en distintas patologías.

Collagen type 1 represents more than 90% of bone matrix. Therefore, quantitation of collagen crosslinks, such as deoxypyridinoline, can provide information on bone resorption degree. An evaluation was made of deoxypyridinoline as well as other bone markets, such as alkaline phosphatase, tartrate resistant acid phosphatase, and hydroxyproline in patients with the diagnosis of osteoporosis. Paget's disease, hyperthyroidism, and chronic renal failure on haemodialysis or not. Deoxypyridinoline levels were significantly increased in patients with osteoporosis, Paget's disease, and hyperthyroidism. Hydroxyproline levels were increased in patients with Paget's disease, and tartrate resistant acid phosphatase was increased in all the entities studied. Deoxypyridinoline can be a more sensitive marker than hydroxyproline, with some advantages, such as its quantitation in a urine specimen and its high bone specificity. In patients with renal failure, tartrate resistant acid phosphatase was the only biochemical marker of bone resorption with increased levels.

Effect of the pH and the importance of the internal standard on the measurement of the urinary catecholamines by high-performance liquid chromatography.

Clinical manifestations of phaeochromocytoma are not always sufficient for its early diagnosis. It is therefore necessary to confirm hypersecretion of catecholamines. Current methods for the measurement of catecholamines are based on their oxidative properties, and the majority of the laboratories often use HPLC methods for catecholamine testing. However, the extraction procedures used for the biogenic amines differ. We use a method of ion-exchange chromatography which is performed at pH 6.5. In order to avoid the spontaneous oxidation of the catecholamines, the urine samples has to be collected on HCl, which gives a pH of approximately 2. Occasionally, the acidified urine sample has a pH less than 1 requiring the addition of NaOH to reach a pH of 6.5, necessary for the adsorption of catecholamines on cation exchanger resins. This phenomenon produces a decrease in the peak areas but the use of an internal standard allows the final results to be corrected.

Optical method for monitoring the concentration of general anesthetics and other small organic molecules. An example of phase transition sensing.

As an example of chemical sensing based on perturbations of thermal phase transitions, we have shown that phospholipids labeled with a fluorescent dye may be used to measure the concentration of general anesthetics and other small organic molecules. The emission maximum of the hydrophobic fluorescent probe Laurdan in phospholipid bilayers shifts from a wavelength of 445 nm below the main phase transition of the lipid to 480 nm above it, with an isosbestic point at approximately 475 nm. The greatest changes in intensity at the transition occur at 440 and 500 nm, so the ratio of the intensities at these two points was used as an "order parameter". The effects of variation of the liposomal preparation method on the order parameter were explored, and it was found that in mixed lipids the parameter varied nearly linearly over the physiological temperature range. Fluorometry detected changes in the order of bilayers caused by solubilization of the anesthetic isoflurane (Forane) and of ethanol. At a defined temperature, the intensity ratio measured in the presence of anesthetic decreases in a concentration-dependent manner. Immobilizing the liposomes in a hydrogel did not perturb the response of the system. This work demonstrates the potential for using lipid phase transitions in an optical sensor for monitoring anesthetics and other small nonpolar molecules.