Cutting edge: urease release by Helicobacter pylori stimulates macrophage inducible nitric oxide synthase

Inducible NO synthase (iNOS) expression and production of NO are both up-regulated with Helicobacter pylori infection in vivo and in vitro. We determined whether major pathogenicity proteins released by H. pylori activate iNOS by coculturing macrophages with wild-type or mutant strains deficient in VacA, CagA, picB product, or urease (ureA(-)). When filters were used to separate H. pylori from macrophages, there was a selective and significant decrease in stimulated iNOS mRNA, protein, and NO(2)(-) production with the ureA(-) strain compared with wild-type and other mutants. Similarly, macrophage NO(2)(-) generation was increased by H. pylori protein water extracts of all strains except ureA(-). Recombinant urease stimulated significant increases in macrophage iNOS expression and NO(2)(-) production. Taken together, these findings indicate a new role for the essential H. pylori survival factor, urease, implicating it in NO-dependent mucosal damage and carcinogenesis.     

ON THE QUANTA OF LIGHT PRODUCED AND THE MOLECULES OF OXYGEN UTILIZED DURING CYPRIDINA LUMINESCENCE

A study of the oxygen consumed per lumen of luminescence during oxidation of Cypridina luciferin in presence of luciferase, gives 11.4 x 10^–5 gm. oxygen per lumen or 88 molecules per quantum of λ = 0.48µ, the maximum in the Cypridina luminescence spectrum. For reasons given in the text, the actual value is probably somewhat less than this, perhaps of the order of 6.48 x 10^–5 gm. per lumen or 50 molecules of oxygen and 100 molecules of luciferin per quantum. It is quite certain that more than 1 molecule per quantum must react. On the basis of a reaction of the type: luciferin + 1/2 O₂ = oxyluciferin + H₂O + 54 Cal., it is calculated that the total efficiency of the luminescent process, energy in luminescence/heat of reaction, is about 1 per cent; and that a luciferin solution containing 4 per cent of dried Cypridina material should rise in temperature about 0.001°C. during luminescence, and contain luciferin in approximately 0.00002 molecular concentration.     

Development ofDentalium following removal of D-quadrant blastomeres at successive cleavage stages

Summary Each primary micromere and macromere of the D-quadrant ofDentalium was deleted, through the mesentoblast stage, to investigate the way in which the polar lobe cytoplasm exerts its influence on development.-D and -1D embryos form an apical tuft but no posttrochal structures.-2D embryos form an apical tuft and a reduced posttrochal region without a shell. -3D and -4D are externally similar to control embryos. -1d embryos and -1c embryos have an apical tuft with a reduced number of cilia. Embryos in which both 1c and 1d are deleted lack the apical tuft.-2d embryos lack shell and most other posstrochal structures. -3d and-4d embryos appear externally equivalent to controls.The polar lobe cytoplasm exerts its influence sequentially, and as inIlyanassa the maximal effect is at the third quartet stage.     

Structure and evolution of the L11, L1, L10, and L12 equivalent ribosomal proteins in eubacteria, archaebacteria, and eucaryotes

The genes corresponding to the L11, L1, L10, and L12 equivalent ribosomal proteins (L11e, L1e, L10e, and L12e) of Escherichia coli have been cloned and sequenced from two widely divergent species of archaebacteria, Halobacterium cutirubrum and Sulfolobus solfataricus, and the L10 and four different L12 genes have been cloned and sequenced from the eucaryote Saccharomyces cerevisiae. Alignments between the deduced amino acid sequences of these proteins and to other available homologous proteins of eubacteria and eucaryotes have been made. The data suggest that the archaebacteria are a distinct coherent phylogenetic group. Alignment of the proline-rich L11e proteins reveals that the N-terminal region, believed to be responsible for interaction with release factor 1, is the most highly conserved region and that there is specific conservation of most of the proline residues, which may be important in maintaining the highly elongated structure of the molecule. Although L11 is the most highly methylated protein in the E. coli ribosome, the sites of methylation are not conserved in the archaebacterial L11e proteins. The L1e proteins of eubacteria and archaebacteria show two regions of very high similarity near the center and the carboxy termini of the proteins. The L10e proteins of all kingdoms are colinear and contain approximately three fourths of an L12e protein fused to their carboxy terminus, although much of this fusion has been lost in the truncated eubacterial protein. The archaebacterial and eucaryotic L12e proteins are colinear, whereas the eubacterial protein has suffered a rearrangement through what appear to be gene fusion events. Within the L12e derived region of the L10e proteins there exists a repeated module of 26 amino acids, present in two copies in eucaryotes, three in archaebacteria, and one in eubacteria. This modular sequence is apparently also present in the L12e proteins of all kingdoms and may play a role in L12e dimerization, L10e-L12e complex formation, and the function of the L10e-L12e complex in translation.     

High cooperativity, specificity, and multiplicity in the protein kinase C-lipid interaction

The number of phosphatidylserine molecules involved in activating protein kinase C was determined in a mixed micelle system where one monomer of protein kinase C binds to one detergent:lipid micelle of fixed composition. Unusually high cooperativity, specificity, and multiplicity in the protein kinase C-phospholipid interaction are demonstrated by examining the lipid dependence of enzymatic activity. The rates of autophosphorylation and substrate (histone) phosphorylation are specifically regulated by the phosphatidylserine content of the micelles. Hill coefficients of 8-11 were calculated for phosphatidylserine-dependent stimulation of enzyme activity, with a maximum occurring in micelles containing greater than or equal to 12 phosphatidylserine molecules. The high specificity that exists is illustrated by the fact that phosphatidylethanolamine and phosphatidylglycerol, but not phosphatidylcholine or phosphatidic acid, can replace only some of the phosphatidylserine molecules. We propose that Ca2+ and acidic phospholipids cause the protein to undergo a conformation change revealing multiple phosphatidylserine binding sites and resulting in the highly cooperative and specific interaction of protein kinase C with phosphatidylserine. Consistent with this, the proteolytic sensitivity of protein kinase C increases approximately 10-fold in the presence of phosphatidylserine and Ca2+ compared to Ca2+ alone. The high degree of cooperativity and specificity may provide a sensitive method for the physiological regulation of protein kinase C by phospholipid.     

ORGANOCHLORINE RESIDUES AND EGGSHELL THINNING IN THE PEREGRINE FALCON FALCO PEREGRINUS MINOR IN ZIMBABWE

Hartley, R.R., Newton, I., & Robertson, M. 1995. Organochlorine residues and eggshell thinning in the Peregrine Falcon Falco peregrinus minor in Zimbabwe. Ostrich 66: 69–73.

Several types of organochlorine residues were found in eggs of Peregrine Falcons Falco peregrinus minor taken in Zimbabwe in 1990. DDE (range = 0.2–22 ppm wet weight; geometric mean 1.8 ppm) was found in all eggs (n = 15) from 13 sites, including two pars in captivity. Eggs from two sites in the mid-Zambezi Valley, the most recently and heavily sprayed areas (5–8 times for tsetse fly Glossina sp. control), had the highest levels, one beyond that regarded as critical for successful reproduction. Mean shell thickness (Ratcliffe index) of the 1990 eggs was 10% (range = 2–29%) lower than the presumed pre-DDT mean. HEOD was detected in two eggs, HCB in one egg, and PCBs in all eggs, but at levels too low to affect breeding performance. Young were fledged from each of 12 sampled sites, yielding 1.86 young per site.     

Wavelength dependence of biological damage induced by UV radiation on bacteria

The biological effects of UV radiation of different wavelengths (UVA, UVB and UVC) were assessed in nine bacterial isolates displaying different UV sensitivities. Biological effects (survival and activity) and molecular markers of oxidative stress [DNA strand breakage (DSB), generation of reactive oxygen species (ROS), oxidative damage to proteins and lipids, and the activity of antioxidant enzymes catalase and superoxide dismutase] were quantified and statistically analyzed in order to identify the major determinants of cell inactivation under the different spectral regions. Survival and activity followed a clear wavelength dependence, being highest under UVA and lowest under UVC. The generation of ROS, as well as protein and lipid oxidation, followed the same pattern. DNA damage (DSB) showed the inverse trend. Multiple stepwise regression analysis revealed that survival under UVA, UVB and UVC wavelengths was best explained by DSB, oxidative damage to lipids, and intracellular ROS levels, respectively.     

A variant in ANKK1 modulates acute subjective effects of cocaine: a preliminary study

This study aimed to evaluate whether functional variants in the ankyrin repeat and kinase domain‐containing 1 (ANKK1) gene and/or the dopamine receptor D2 (DRD2) gene modulate the subjective effects (reward or non‐reward response to a stimulus) produced by cocaine administration. Cocaine‐dependent participants (N = 47) were administered 40 mg of cocaine or placebo at time 0, and a subjective effects questionnaire (visual analog scale) was administered 15 min prior to cocaine administration, and at 5, 10, 15 and 20 min following administration. The influence of polymorphisms in the ANKK1 and DRD2 genes on subjective experience of cocaine in the laboratory was tested. Participants with a T allele of ANKK1 rs1800497 experienced greater subjective ‘high’ (P = 0.00006), ‘any drug effect’ (P = 0.0003) and ‘like’ (P = 0.0004) relative to the CC genotype group. Although the variant in the DRD2 gene was shown to be associated with subjective effects, linkage disequilibrium analysis revealed that this association was driven by the ANKK1 rs1800497 variant. A participant's ANKK1 genotype may identify individuals who are likely to experience greater positive subjective effects following cocaine exposure, including greater ‘high’ and ‘like’, and these individuals may have increased vulnerability to continue using cocaine or they may be at greater risk to relapse during periods of abstinence. However, these results are preliminary and replication is necessary to confirm these findings.     

The personal and health service impact of falls in 85 year olds: cross-sectional findings from the Newcastle 85+ cohort study

Introduction

Falls are common in older people and increase in prevalence with advancing old age. There is limited knowledge about their impact in those aged 85 years and older, the fastest growing age group of the population. We investigated the prevalence and impact of falls, and the overlap between falls, dizziness and blackouts, in a population-based sample of 85 year olds.

Methods

Design: Cross-sectional analysis of baseline data from Newcastle 85+ Cohort Study. Setting: Primary care, North-East England. Participants: 816 men and women aged 85 years. Measurements: Structured interview with research nurse. Cost-consequence analysis of fall-related healthcare costs.

Results

Over 38% (313/816) of participants had fallen at least once in the previous 12 months and of these: 10.6% (33/312) sustained a fracture, 30.1% (94/312) attended an emergency department, and 12.8% (40/312) were admitted to hospital. Only 37.2% (115/309) of fallers had specifically discussed their falls problem with their general practitioner and only 12.7% (39/308) had seen a falls specialist. The average annual healthcare cost per faller was estimated at £202 (inter-quartile range £174–£231) or US$329 ($284–$377). ‘Worry about falling’ was experienced by 42.0% (128/305) of fallers, ‘loss of confidence’ by 40.0% (122/305), and ‘going out less often’ by 25.9% (79/305); each was significantly more common in women, odds ratios (95% confidence interval) for women: men of 2.63 (1.45–4.55), 4.00 (2.27–7.14), and 2.86 (1.54–5.56) respectively. Dizziness and blackouts were reported by 40.0% (318/796) and 6.4% (52/808) of participants respectively. There was marked overlap in the report of falls, dizziness and blackouts.

Conclusions

Falls in 85 year olds are very common, associated with considerable psychological and physical morbidity, and have high impact on healthcare services. Wider use of fall prevention services is needed. Significant expansion in acute and preventative services is required in view of the rapid growth in this age group.