Reversible microsomal binding of hepatic aldolase

Fructose-1,6-bisphosphate aldolase (-fructose-1,6-bisphosphate -glyceraldehyde-3-phosphate lyase, EC 4.1.2.13) partitions between the microsomes and the cytosol when a rat liver homogenate is fractionated by differential centrifugation. Gel electrophoresis and immunodiffusion indicate that the one isozyme present in the liver of the young adult rat is found in both fractions. The association of the aldolase with membranes is differentially sensitive to a variety of metabolites and inorganic salts. In the absence of cellular salts, 1 mM fructose 1,6-bisphosphate or glucose 1,6-bisphosphate elutes 50% of the enzyme from the microsomes. About 9 mM Pi or citrate is necessary to produce the same effect. With other metabolites or inorganic salts higher concentrations are required. The fraction of total enzyme which partitions with the microsomes when a homogenate is submitted to high speed centrifugation, correlates inversely with the level of fructose 1,6-bisphosphate in the supernatant solution and this concentration is higher when the tissue concentration in the homogenate is greater. The Km for fructose 1,6-bisphosphate of 3 [middle dot] 10-4 for aldolase bound to microsomes is decreased to 6 [middle dot] 10-6 M when the enyme is dissociated from the membranes with salt. These observations appear relevant to the ongoing discussion regarding the physiological relevance of the subcellular localization of glycolytic enzymes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24233/1/0000493.pd

Energy-linked reactions in hypothyroid rat liver submitochondrial vesicles

Processes in submitochondrial vesicles obtained from the liver mitochondria of hypothyroid rats were compared at 25-30[deg] with those from normal rats. Hypothyroidism did not alter the rates of oxidation of succinate or [beta]-hydroxybutyrate, or energy-independent transhydrogenation of pyridine nucleotides. Energy-dependent transhydrogenation supported either by added ATP or by succinate oxidation was doubled in the vesicles of hypothyroid rats, whereas ATP-supported reversed electron-flow was unchanged. Hormone injection corrected the abnormal rate. Since submitochondrial vesicles phosphorylate ADP slowly at 30[deg] in hypothyroidism (5), these data suggest that the thyroid state controls the use rather than the supply of available energy potential.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21791/1/0000186.pd

An architecture for integrating multiple real time data feeds

This thesis investigates 'industry strength' solutions for integrating multiple real time data feeds. It addresses one of the major problems challenging computing namely 'information overload'. The thesis focuses on those problems faced by a user of multiple data sources, either real time data feeds or databases. The thesis' goal is a system architecture providing a generic interface which allows the connection of one or more data sources to a unified collection point. On entering the system the data is screened and filtered for information which is pertinent to the end user. This data is then available for other programs that use the data, through a standard interface. The thesis comprises four parts: a critique of existing commercial real time products, and then the invention of three experimental real time systems, constituting the core of this research. These systems have been created in collaboration with industry, providing unique end user feed back, and also ensuring a degree of compliance with industry standards. The three experimental systems comprise: (i) a 16 bit real time system for providing private investors with financial information; (ii) a 32-bit system for tracking buses in real time; (iii) a 32 bit 'generic' real time system which caters for multiple feeds. The three systems have all been designed and implemented by the author, and the systems are now being tested in a commercial environment. The critique examines several commercial real time systems and analyses their key features relating to information overload. It studies the fundamental aspects of real lime data processing with specific reference to the industry standard Microsoft Windows in the PC environment. The second part describes the design and implementation of a 16-bit real time system for providing end users with stock exchange data from one or more data sources. To provide experimental data on the use of the system it was built in collaboration with Updata Software. It utilises 16 bit DLLs for multiple process information sharing and providing data in a 'soft' real time manner. The third part describes the design and implementation of a 32-bit real time system. This system provides feedback on vehicle positions and with the aid of Hampshire County Council is being tested for passenger information systems on buses. It utilises shared global memory blocks to share information between processes. The final part presents the new 'generic' system architecture, whose design draws on experience gained from the previous two systems and the feedback, provided from users. Lessons learnt from previous systems include the need for integration of filtering into the system and providing an open interface to ease data input from new data feeds. This system also addresses the need for compliance with industry standards. It makes strong use of object architectures and, being WOSA compliant, provides COM interfaces to satisfy the need to share information and provide an open interface. The two chapters covering this work contain the design of the system and the strategy employed to implement the design, and then test the system. The thesis and the software implemented make three contributions to science: i) it reduces information overload by integrating the data from multiple sources and providing a single interface for accessing that data, ii) it provides techniques for bringing real time data to the personal computer desktop, and iii) it helps to personalise the data by providing a simple filtering mechanism and an interface for more complex filtering systems. An innovation of this thesis is that the implementations of the designs have been taken through to industry products, in order to provide feedback