PARK3 influences age at onset in Parkinson disease: a genome scan in the GenePD study

Parkinson disease (PD) is a late-onset neurodegenerative disorder. The mean age at onset is 61 years, but the disease can range from juvenile cases to cases in the 8th or 9th decade of life. The parkin gene on chromosome 6q and loci on chromosome 1p35-36 and 1p36 are responsible for some cases of autosomal recessive early-onset parkinsonism, but they do not appear to influence susceptibility or variability of age at onset for idiopathic PD. We have performed a genomewide linkage analysis using variance-component methodology to identify genes influencing age at onset of PD in a population of affected relatives (mainly affected sibling pairs) participating in the GenePD study. Four chromosomal loci showed suggestive evidence of linkage: chromosome 2p (maximum multipoint LOD [MaxLOD] = 2.08), chromosome 9q (MaxLOD = 2.00), chromosome 20 (MaxLOD = 1.82), and chromosome 21 (MaxLOD = 2.21). The 2p and 9q locations that we report here have previously been reported as loci influencing PD affection status. Association between PD age at onset and allele 174 of marker D2S1394, located on 2p13, was observed in the GenePD sample (P=.02). This 174 allele is common to the PD haplotype observed in two families that show linkage to PARK3 and have autosomal dominant PD, which suggests that this allele may be in linkage disequilibrium with a mutation influencing PD susceptibility or age at onset of PD.     

Quantitation of 2-chlorovinylarsonous acid in human urine by automated solid-phase microextraction--gas chromatography--mass spectrometry

Lewisite [dichloro(2-chlorovinyl)arsine] is a highly toxic chemical warfare agent with vesicant properties. The accidental exposure to lewisite or its intentional use as a chemical terrorism weapon are a public health threat and warrant investigations for the development of analytical methods to detect biomarkers of exposure to lewisite. Under aqueous conditions, lewisite rapidly hydrolyzes to the non-volatile 2-chlorovinylarsonous acid (CVAA). We have developed a sensitive, simple, and automated method for measuring CVAA in human urine. The assay is based on the use of solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) after derivatization of the CVAA with 1,3-propanedithiol (PDT). The volatile CVAA-PDT is adsorbed onto a SPME fiber and analyzed by GC-MS. The assay was validated on human urine samples spiked with CVAA to determine the accuracy, precision, and limit of detection (LOD). The LOD was 7.4 pg in 1 ml of urine.     

Binding of human hemoglobin by Haemophilus influenzae

Abstract Binding of biotinylated human hemoglobin to Haemophilus influenzae was detected when organisms were grown in heme-deplete, but not heme-replete, conditions. Hemoglobin binding was completely inhibited by a 100-fold excess of unlabelled human hemoglobin or human hemoglobin complexed with human haptoglobin. Binding was only partially inhibited by rat hemoglobin, bovine hemoglobin, human globin, and bovine globin, and not at all by heme, human serum albumin, bovine serum albumin, human transferrin, or myoglobin. Hemoglobin binding was saturable at 16–20 ng of hemoglobin per 10⁹ cfu. Binding of human hemoglobin was detected in serotypes a-f and serologically non-typable strains of H. influenzae , as well as Haemophilus haemolyticus but not Haemophilus parainfluenzae, Haemophilus aphrophilus, Haemophilus parahaemolyticus , or Escherichia coli .     

Is morphine dependence mediated exclusively by the Mu receptor?

Regional cerebral glucose utilization (RCGU) and behavior during naloxone precipitated withdrawal were studied in rats made dependent on either sufentanil, a highly selective mu opiate agonist, or morphine. Changes in RCGU during withdrawal in 23 of 24 anatomically related limbic and brainstem structures were indistinguishable between rats dependent on morphine or sufentanil. Linear regression analysis indicated that RCGU changes during withdrawal in these two groups were highly correlated (r=0.95). Withdrawal behaviors (autonomic signs of withdrawal, jumps, weight loss, and incidence of diarrhea) were likewise indistinguishable between the two groups. The correlations of both these measurements of dependence suggest that chronic occupation of mu opiate receptors alone is sufficient to produce dependence that is indistinguishable from morphine dependence.     

Calcium gating of H+ fluxes in chloroplasts affects acid-base-driven ATP formation

In previous work, calcium ions, bound at the lumenal side of the CF₀H⁺ channel, were suggested to keep a H⁺ flux gating site closed, favoring sequestered domain H⁺ ions flowing directly into the CF₀-CF₁ and driving ATP formation by a localized gradient. Treatments expected to displace Ca⁺⁺ from binding sites had the effect of allowing H⁺ ions in the sequestered domains to equilibrate with the lumen, and energy coupling showed delocalized characteristics. The existence of such a gating function implies that a closed-gate configuration would block lumenal H⁺ ions from entering the CF₀-CF₁ complex. In this work that prediction was tested using as an assay the dark, acid-base jump ATP formation phenomenon driven by H⁺ ions derived from succinic acid loaded into the lumen.Chlorpromazine, a photoaffinity probe for many proteins having high-affinity Ca⁺⁺-binding sites, covalently binds to the 8-kDa CF₀ subunit in the largest amounts when there is sufficient Ca⁺⁺ to favor the localized energy coupling mode, i.e., the gate closed configuration. Photoaffinity-bound chlorpromazine blocked 50% or more of the succinate-dependent acid-base jump ATP formation, provided that the ionic conditions during the UV photoaffinity treatment were those which favor a localized energy coupling pattern and a higher level of chlorpromazine labeling of the 8-kDa CF₀ subunit. Thylakoids held under conditions favoring a delocalized energy coupling mode and less chlorpromazine labeling of the CF₀ subunit did not show any inhibition of acid-base jump ATP formation.Chlorpromazine and calmidazolium, another Ca⁺⁺-binding site probe, were also shown to block redox-derived H⁺ initially released into sequestered domains from entering the lumen, at low levels of domain H⁺ accumulation, but not at higher H⁺ uptake levels; ie., the closed gate state can be overcome by sufficiently acidic conditions. That is consistent with the observation that the inhibition of lumenal succinate-dependent ATP formation by photoaffinity-attached chlorpromazine can be reversed by lowering the pH of the acid stage from 5.5 to 4.5.The evidence is consistent with the concept that Ca⁺⁺ bound at the lumenal side of the CF₀ H⁺ channel can block H⁺ flux from either direction, consistent with the existence of a molecular structure in the CF₀ complex having the properties of a gate for H⁺ flux across the inner boundary of the CF₀. Such a gate could control the expression of localized or delocalized energy coupling gradients.     

Ribosomal protein L2 is involved in the association of the ribosomal subunits, tRNA binding to A and P sites and peptidyl transfer

Ribosomal proteins L2, L3 and L4, together with the 23S RNA, are the main candidates for catalyzing peptide bond formation on the 50S subunit. That L2 is evolutionarily highly conserved led us to perform a thorough functional analysis with reconstituted 50S particles either lacking L2 or harboring a mutated L2. L2 does not play a dominant role in the assembly of the 50S subunit or in the fixation of the 3'-ends of the tRNAs at the peptidyl-transferase center. However, it is absolutely required for the association of 30S and 50S subunits and is strongly involved in tRNA binding to both A and P sites, possibly at the elbow region of the tRNAs. Furthermore, while the conserved histidyl residue 229 is extremely important for peptidyl-transferase activity, it is apparently not involved in other measured functions. None of the other mutagenized amino acids (H14, D83, S177, D228, H231) showed this strong and exclusive participation in peptide bond formation. These results are used to examine critically the proposed direct involvement of His229 in catalysis of peptide synthesis.     

Elimination of Mange Mites <Emphasis Type="Italic">Sarcoptes scabiei</Emphasis> var. <Emphasis Type="Italic">suis</Emphasis>from Two Naturally Infested Danish Sow Herds Using a Single Injection Regime with Doramectin

Attempts to eliminate Sarcoptes scabiei var. suis were made in 2 naturally infested sow herds, by intramuscular (IM) injection of doramectin (Dectomax^®, Pfizer, New York, USA). A single injection strategy was used. In one of the herds, the environment was treated with an acaricide following dry cleaning of floors, walls and equipment. In the second herd, no environmental treatment was performed. Results were measured by skin lesion scoring, ear scrapings to show Sarcoptes scabiei var. suis, and calculating rubbing index throughout the observation period of 20 months following treatment. Skin lesion scores decreased and stayed low following treatment for the entire observation period. Live Sarcoptes scabiei var. suis mites were isolated prior to treatment from both herds, but not following treatment. Rubbing index decreased following treatment, but was occasionally at or above 0.4. The results of these studies indicate that elimination of Sarcoptes scabiei var. suis from 2 naturally infested herds was successful, using doramectin in a single injection strategy. Precautions must be taken to ensure adequate dosing of every pig, and to avoid reinfestation due to poor biosecurity.     

Host-pathogen interactions promoting inflammatory Lyme arthritis: use of mouse models for dissection of disease processes

Recent studies have confirmed the infectious and inflammatory nature of arthritis induced by Borrelia burgdorferi, or Lyme arthritis. This arthritis is directed by the presence of the bacteria in joint tissue, and is mediated through activation of the Toll-like receptor 2 (TLR2) signaling pathways by borrelial lipoproteins. Several host genes regulate the severity of arthritis, possibly by regulating the balance of pro- and anti-inflammatory responses.