Comparison of the distribution of D-1 and D-2 dopamine receptors in the rat brain

The distribution of dopamine type 1 (D-1) and dopamine type 2 (D-2) receptors in the brain have been compared as assessed by the technique of autoradiography after labelling with highly selective ligands. D-1 receptors, as evidenced by the specific binding of [3H]R-(+)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-IH-3-benzazepine -7- ol (SCH 23390), were found in high concentrations in the caudate-putamen, nucleus accumbens, islands of Calleja, olfactory tubercle and the zona reticulata of the substantia nigra. A similar but distinct distribution was seen for [3H]sulpiride, a ligand which is highly selective for D-2 receptors. Like [3H]SCH 23390, this ligand also labelled the caudate-putamen, nucleus accumbens, islands of Calleja and the olfactory tubercle; however, only a very low density of D-2 receptors could be found in the zona reticulata of the substantia nigra, while a greater degree of binding was present in the zona compacta. Additional brain areas which contained D-1 but not D-2 receptors included the cerebral cortex, accessory olfactory nucleus, amygdala, thalamus, suprachiasmatic nucleus, choroid plexus, claustrum, endopiriform nucleus, zona incerta, dorsal lateral geniculate nucleus and the dentate gyrus. D-2 receptors were also found in areas which appeared to contain only low amounts of D-1 receptors such as the glomerular layer of the olfactory bulb, bed nucleus of the stria terminalis, hypothalamus, habenula, stratum lacunosum moleculare of the hippocampus, intermediate lobe of the pituitary, lateral mammillary nucleus, periaqueductal gray, inferior colliculus, nodulus of the cerebellum and the dorsal horn of the spinal cord. The results show the precise localization of dopamine receptors throughout the brain and provide a means of direct comparison between the distribution of dopamine receptor subtypes. These subtypes are pharmacologically and anatomically distinct entities and their comparison indicates areas where additional biochemical and neuroanatomical studies may be performed to elucidate the roles for these receptor subtypes in the central nervous system.     

Solid-phase enzyme-linked immunosorbent assay for hepatitis E virus IgG and IgM antibodies utilizing recombinant antigens and synthetic peptides.

Four recombinant antigens representing two distinct antigenic domains from two different strains of hepatitis E virus (HEV), were used individually to develop four ELISAs designed to detect antibodies to HEV. Both IgG and IgM class antibodies to HEV were detected in 7 of 8 pedigreed serum/plasma from known outbreaks of HEV in Mexico, Burma, Somalia and Pakistan. In addition, specific HEV-antibodies were detected in cynomolgus macaques following inoculation with various HEV strains. Anti-HEV was also detected in 8 of 386 (2.1%) randomly selected American blood donors. Supplemental tests utilizing both synthetic peptides and specific blocking assays provided additional serologic data confirming the presence of anti-HEV. Similar prevalence studies on a limited number of available sera from other geographical regions (Alaska, Japan, Germany, New Zealand, Thailand and Mexico) confirmed the presence of anti-HEV in at least 1.1 to 7.6% of the specimens.     

Association of DJ-1 and parkin mediated by pathogenic DJ-1 mutations and oxidative stress

The identification of rare monogenic forms of Parkinson's disease (PD) has provided tremendous insight into the molecular pathogenesis of this disorder. Heritable mutations in alpha-synuclein, parkin, DJ-1 and PINK1 cause familial forms of PD. In the more common sporadic form of PD, oxidative stress and derangements in mitochondrial complex-I function are considered to play a prominent role in disease pathogenesis. However, the relationship of DJ-1 with other PD-linked genes and oxidative stress has not been explored. Here, we show that pathogenic mutant forms of DJ-1 specifically but differentially associate with parkin, an E3 ubiquitin ligase. Chemical cross-linking shows that pathogenic DJ-1 mutants exhibit impairments in homo-dimer formation, suggesting that parkin may bind to monomeric DJ-1. Parkin fails to specifically ubiquitinate and enhance the degradation of L166P and M26I mutant DJ-1, but instead promotes their stability in cultured cells. The interaction of parkin with L166P DJ-1 may involve a larger protein complex that contains CHIP and Hsp70, perhaps accounting for the lack of parkin-mediated ubiquitination. Oxidative stress also promotes an interaction between DJ-1 and parkin, but this does not result in the ubiquitination or degradation of DJ-1. Parkin-mediated alterations in DJ-1 protein stability may be pathogenically relevant as DJ-1 levels are dramatically increased in the detergent-insoluble fraction from sporadic PD/DLB brains, but are reduced in the insoluble fraction from parkin-linked autosomal recessive juvenile-onset PD brains. These data potentially link DJ-1 and parkin in a common molecular pathway at multiple levels that may have important implications for understanding the pathogenesis of inherited and sporadic PD.     

Brief intense exercise followed by passive recovery modifies the pattern of fuel use in humans during subsequent sustained intermittent exercise

The role of work period duration as the principal factor influencing carbohydrate metabolism during intermittent exercise has been investigated. Fuel oxidation rates and muscle glycogen and free carnitine content were compared between two protocols of sustained intermittent intense exercise with identical treadmill speed and total work duration. In the first experiment subjects (n=6) completed 40 min of intermittent treadmill running involving a work : recovery cycle of 6 : 9 s or 24 : 36 s on separate days. With 24 : 36 s exercise a higher rate of carbohydrate oxidation approached significance (P=0.057), whilst fat oxidation rate was lower (P ≤ 0.01) and plasma lactate concentration higher (P ≤ 0.01). Muscle glycogen was lower post‐exercise with 24 : 36 s (P ≤ 0.05). Muscle free carnitine decreased (P ≤ 0.05), but there was no difference between protocols. In the second experiment a separate group of subjects (n=5) repeated the intermittent exercise protocols with the addition of a 10‐min bout of intense exercise, followed by 43 ± 5 min passive recovery, prior to sustained (40 min) intermittent exercise. For this experiment the difference in fuel use observed previously between 6 : 9 s and 24 : 36 s was abolished. Carbohydrate and fat oxidation, plasma lactate and muscle glycogen levels were similar in 6 : 9 s and 24 : 36 s. When compared with the first experiment, this result was because of reduced carbohydrate oxidation in 24 : 36 s (P ≤ 0.05). There was no difference, and no change, in muscle free carnitine between protocols. A 10‐min bout of intense exercise, followed by 43 ± 5 min of passive recovery, substantially modifies fuel use during subsequent intermittent intense exercise.     

Sequence relations and coding properties of a subgenomic RNA isolated from barley stripe mosaic virus

A subgenomic (SG) RNA ( approximately 800 nucleotides) is a minor component of barley stripe mosaic virus RNAs. The SG-RNAs isolated from the Type and North Dakota 18 (ND18) strains of BSMV have sequence homology with RNA 2 of the ("pseudo-two component") Type strain, which has two electrophoretic components, but only limited homology is evident with RNA 2 of the ND18 and Norwich strains, which have three electrophoretic components ("three component" strain). Instead, eDNAs from SG-RNA hybridize most efficiently with RNA 3 of the ND18 and Norwich strains. In wheat germ extracts the SG-RNAs direct the synthesis of two polypeptides with apparent molecular weights of 20 to 21 x 10(3). However, these two polypeptides were difficult to detect by polyacrylamide gel electrophoresis of extracts from Type- or ND18-infected barley and so appear not to accumulate during infection.     

Effect of a Polymeric Additive on the Pore‐Size Distribution and Shrinking Process of a Hydrogel Network

A systematic comparison of the effect of architectural modifications to the network structure on the internal microstructure of N‐isopropylacrylamide (NIPA) based hydrogels showed that the addition of a second component to the network significantly increased the proportion of macropores in the network. The second components considered were short poly(N‐isopropylacrylamide) (PNIPAM) chains grafted to the network backbone, high‐molecular‐weight polyacrylamide (PAM) chains, or microsphere particles of PNIPAM. Structures are proposed for each of the modified gel networks taking into account the new structural information. Through a combination of the pore size and network structure data reported here, and with the shrinking data obtained previously, shrinking mechanisms are proposed for each of the modified network structures. In all cases, the enhanced shrinking rates were directly caused by the presence of the second component, which acted as nuclei for shrinking (graft‐PNIPAM and PNIPAM microspheres) or as water‐release channels (PAM gel), and indirectly caused by the second components via their affect on the network microstructure.

Proposed structures for the architecturally modified gels based on the pore‐size information. Graft‐PNIPAM gel. The freely mobile graft chains prevent chains from meeting resulting in larger pores.     

The effect of age on the fibrinolytic enzyme system

Components of the fibrinolytic enzyme system, FR-antigen and fibrinogen, were measured in 20 healthy volunteers aged 20-40 years and in 61 elderly subjects aged 66-96 years. Plasminogen activator levels did not significantly differ between the 20-40 and 66-75 age groups, but were higher in those over 75. Plasminogen showed no change with age except for a fall in those over 75. Fibrinogen, FR-antigen, alpha(1)-antitrypsin, and alpha(2)-macroglobulin all rose with age, but the mean fibrinogen concentration fell in the very elderly.