Disclosed herein is a two-piece sensor assembly that includes an attachment collar configured to attach to a body surface of a patient and comprising at least one opening, and a skin sensor configured to seat into the at least one opening in the attachment collar. The skin sensor includes at least one radiation source configured to irradiate the body surface with at least one interrogation light, at least one detector configured to detect at least one response light incident from the direction of the body surface, and a controller communicatively coupled to the skin sensor, the attachment collar or both, wherein the controller is programed to transmit information and to receive information between the controller and the skin sensor and/or the attachment collar, and to control the at least one radiation source and the at least one detector.

The present invention relates to pyrazine derivatives such as those represented by Formulas I and II. X.sup.1 to X.sup.4 formulas I and II may be characterized as electron withdrawing groups, white Y.sup.1 to Y.sup.4 of Formulas I and II may be characterized as electron donating groups. Pyrazine derivatives of the present invention may be utilized in assessing organ (e.g., kidney) function. In a particular example, an effective amount of a pyrazine derivative that is capable of being renally cleared may be administered into a patient's body. The pyrazine derivative may capable of one or both absorbing and emanating spectral energy of at least about 400 nm (e.g., visible and/or infrared light). At least some of the derivative that is in the body may be exposed to spectral energy and, in turn, spectral energy may emanate from the derivative. This emanating spectral energy may be detected and utilized to determine renal function of the patient.

##STR00001##

The present invention relates to pyrazine derivatives such as those represented by Formulas I and II. X.sup.1 to X.sup.4 formulas I and II may be characterized as electron withdrawing groups, white Y.sup.1 to Y.sup.4 of Formulas I and II may be characterized as electron donating groups. Pyrazine derivatives of the present invention may be utilized in assessing organ (e.g., kidney) function. In a particular example, an effective amount of a pyrazine derivative that is capable of being renally cleared may be administered into a patient's body. The pyrazine derivative may capable of one or both absorbing and emanating spectral energy of at least about 400 nm (e.g., visible and/or infrared light). At least some of the derivative that is in the body may be exposed to spectral energy and, in turn, spectral energy may emanate from the derivative. This emanating spectral energy may be detected and utilized to determine renal function of the patient.

##STR00001##

A process for preparing pyrimido[4,5-g]pteridine-2,4,7,9-tetraol, or a salt thereof, is provided. A process for the preparation of 3,6-diaminopyrazine-2,5-dicarboxylic acid, or a salt thereof, from pyrimido[4,5-g]pteridine-2,4,7,9-tetraol, or a salt thereof, is further provided. A process for preparing a substituted pteridine compound, or a salt thereof, is further provided. A process for the preparation of a N-substituted 3,6-diaminopyrazine-2,5-dicarboxylic acid from a substituted pteridine compound, or a salt thereof, is further provided.

A process for preparing pyrimido[4,5-g]pteridine-2,4,7,9-tetraol, or a salt thereof, is provided. A process for the preparation of 3,6-diaminopyrazine-2,5-dicarboxylic acid, or a salt thereof, from pyrimido[4,5-g]pteridine-2,4,7,9-tetraol, or a salt thereof, is further provided. A process for preparing a substituted pteridine compound, or a salt thereof, is further provided. A process for the preparation of a N-substituted 3,6-diaminopyrazine-2,5-dicarboxylic acid from a substituted pteridine compound, or a salt thereof, is further provided.

The present invention provides compounds useful in treating or preventing inflammation, acne, bacterial conditions and promoting the appearance of healthy skin and compositions including these compounds.

The present invention provides compounds useful in treating or preventing inflammation, acne, bacterial conditions and promoting the appearance of healthy skin and compositions including these compounds.

The present invention provides phenyl-2-hydroxy-acetylamino-2-methyl-phenyl compounds, to pharmaceutical compositions comprising the compounds, to methods of using the compounds to treat physiological disorders such as cancer.

The present invention provides phenyl-2-hydroxy-acetylamino-2-methyl-phenyl compounds, to pharmaceutical compositions comprising the compounds, to methods of using the compounds to treat physiological disorders such as cancer.

The present invention relates to a novel salt of 2-(4-(5,6-diphenylpyrazin-2-yl)(isopropyl)amino)butoxy)acetic acid (hereinafter referred to as “Compound B”) and a crystal of the salt thereof.