Abstract: An improved sensor apparatus of a kind that positions a semi-permeable membrane adjacent to an electrode assembly, for measuring a predetermined parameter, e.g., glucose concentration, of an adjacent fluid sample. A special compressible ring serves a first function of tensioning the membrane so that it is maintained in intimate contact with the electrode assembly, and it further serves a second function of sealing the fluid sample from the external environment.

Abstract: A subcutaneously implantable medication infusion device includes a variable capacity reservoir for receiving and storing fluid medication for delivery to a catheter which directs the medication to a specific infusion location in the body. A control assembly is interposed between the reservoir and the catheter to facilitate and control the transfer of the medication from the reservoir to the catheter in a safe and efficient manner. The control assembly includes a self-recharging pump and a normally closed valve, both of which are manually actuable by percutaneous pressure when subcutaneously implanted, and defines a portion of a fluid flow conduit between the reservoir and the catheter. The control assembly is constructed to permit the infusion of a measured bolus of medication on demand through manual percutaneous manipulation of the control assembly.