Prediction of signal peptides and signal anchors by a hidden Markov model

A hidden Markov model of signal peptides has been developed. It contains submodels for the N-terminal part, the hydrophobic region, and the region around the cleavage site. For known signal peptides, the model can be used to assign objective boundaries between these three regions. Applied to our data, the length distributions for the three regions are significantly different from expectations. For instance, the assigned hydrophobic region is between 8 and 12 residues long in almost all eukaryotic signal peptides. This analysis also makes obvious the difference between eukaryotes, Gram-positive bacteria, and Gram-negative bacteria. The model can be used to predict the location of the cleavage site, which it finds correctly in nearly 70% of signal peptides in a cross-validated test--almost the same accuracy as the best previous method. One of the problems for existing prediction methods is the poor discrimination between signal peptides and uncleaved signal anchors, but this is substantially improved by the hidden Markov model when expanding it with a very simple signal anchor model.

The role of [Ca2+]i, membrane potential and pHi in the relaxation of rat mesenteric arteries to hyperosmolar acetate

In vitro both acetate and hyperosmolarity cause vasodilation, which could be physiologically important during food ingestion and during peritoneal dialysis. The purpose of this study was to investigate the role of the intracellular calcium concentration ([Ca2+]i, measured with fura-2), membrane potential (measured with glass microelectrodes) and intracellular pH [pHi, measured with bis-carboxyethylcarboxyfluorescein (BCECF)] in the vasodilation. Hyperosmolar sodium acetate (30 mM) concentration dependently relaxed noradrenaline-precontracted arteries. This response was associated with hyperpolarization and a fall in [Ca2+]i. In arteries precontracted with 50 mM K+ the relaxation was associated with a decrease of [Ca2+]i but no change in membrane potential. Isoosmolar sodium acetate neither relaxed or affect [Ca2+]i of K+-precontracted arteries, but induced a small relaxation with no reduction in [Ca2+]i in noradrenaline-precontracted arteries. Hyperosmolar acetate caused a transient reduction of pHi that was unrelated to relaxation. It is concluded that the mechanisms responsible for the relaxation to hyperosmolar acetate involve a decrease of [Ca2+]i, which is only partly explained by hyperpolarization and probably a decrease in the sensitivity of the contractile proteins to [Ca2+]i. pHi seems not to play a role in these effects.

Humerospinous distance measurements: accuracy and usefulness for predicting shoulder dystocia in delivery at term

OBJECTIVE

To investigate if the humerospinous distance, as an indicator of shoulder width, could predict shoulder dystocia at term.

DESIGN

Prospective cross-sectional study of a stratified reference group of healthy women and a test group of women with risk factors for shoulder dystocia. Measurements were not revealed. Outcome measures were difficulties with delivery of the shoulders and correlation with maternal body mass and birth weight.

SUBJECTS

Seventy-two women with singleton pregnancies at a University Clinic: 32 women at 39-42 weeks for reference and 40 women in an at-risk test group (weight > 90 kg, weight gain > 20 kg, previous macrosomic baby, history of shoulder dystocia/difficult delivery, clinical suspicion of a large baby). Women with a breech fetus, twins and those not able to deliver vaginally were excluded.

METHODS

Fetal shoulders were measured from the convergence of the cervical spinous processes at the approximate cervicothoracic vertebral junction to the medial border of the humeral head. Correlations were made with maternal body mass, birth weight, birth weight estimation, ultrasound and postnatal humerospinous measurements.

RESULTS

One case of shoulder dystocia in a fetus with an average humerospinous measurement occurred in the reference group and there were no cases in the test group. There was no predictive value of a large humerospinous measurement and no correlation with maternal or fetal size. Movement of the fetal arm could change the humerospinous distance considerably, which could account for the difference between a normal and large measurement.

CONCLUSION

The humerospinous distance cannot be used to predict shoulder dystocia.

Analgesic dose-response relationship of ibuprofen 50, 100, 200, and 400 mg after surgical removal of third molars: a single-dose, randomized, placebo-controlled, and double-blind study of 304 patients

The purpose of this single-dose, randomized, placebo-controlled, and double-blind study was to evaluate the analgesic dose-response relationship of 50-mg, 100-mg, 200-mg, and 400-mg doses of ibuprofen after third molar surgery. Patients were instructed to take a single dose of either placebo or 50 mg, 100 mg, 200 mg, or 400 mg of ibuprofen when the postoperative pain was moderate to severe. Acetaminophen 500 mg was used as a rescue medication. Pain intensity, pain relief, and any possible adverse events were recorded on self-administered questionnaires hourly for 6 hours after intake of study medication. If rescue medication was taken, the time of intake was registered. A total of 304 patients entered the study, and 258 complied with the protocol. A positive analgesic dose-response relationship of 50-mg, 100-mg, 200-mg, and 400-mg doses of ibuprofen was observed when evaluated by pain intensity difference, sum of pain intensity difference, pain relief, total pain relief, and survival distribution of patients not taking rescue medication. Although significant pain relief was seen after a dose of 50 mg ibuprofen, ibuprofen 400 mg provided maximum pain relief and the longest duration of analgesic effect. Mild transient adverse events were reported by 6.8% of the patients. However, there was no significant difference in frequency between the placebo and 50 mg, 100 mg, 200 mg, and 400 mg ibuprofen dose groups.

Studies on mast cells and histamine release in psoriasis: the effect of ranitidine

The purpose of this study was to investigate histamine and skin mast cells in psoriasis before and during 6 months of treatment with high-dose ranitidine. Sixteen psoriasis patients, presenting a mean PASI score of 15.4, were compared with 13 age- and sex-matched healthy controls. Resting extracellular skin levels of histamine and histamine release to mast cell secretagogues, as measured by the microdialysis technique, were increased in involved psoriasis skin compared to normal skin in the controls. Plasma histamine, but not basophil histamine release, was significantly increased in the patients. Mast cells and lymphocytes were significantly increased in numbers in involved versus non-involved skin in the patients, the lymphocytes being predominantly T-lymphocytes expressing HLA-DR activation. During 6 months of ranitidine treatment, mean PASI score of 15.4 decreased to 5.8. The lymphocyte infiltration, but not mast cell numbers, was significantly reduced during treatment, and histamine release to mast cell secretagogues was normalized. These observations suggest that skin mast cells in active psoriasis are functionally hyperreactive. The biochemical findings together with the clinical effect of ranitidine indicate that histamine may be involved in the pathophysiology of psoriasis.

Group I-like ribozymes with a novel core organization perform obligate sequential hydrolytic cleavages at two processing sites

A new category of self-splicing group I introns with conserved structural organization and function is found among the eukaryotic microorganisms Didymium and Naegleria. These complex rDNA introns contain two distinct ribozymes with different functions: a regular group I splicing-ribozyme and a small internal group I-like ribozyme (GIR1), probably involved in protein expression. GIR1 was found to cleave at two internal sites in an obligate sequential order. Both sites are located 3' of the catalytic core. GIR1-catalyzed transesterification reactions could not be detected. We have compared all available GIR1 sequences and propose a common RNA secondary structure resembling that of group I splicing-ribozymes, but with some important differences. The GIR1s lack most peripheral sequence components, as well as a P1 segment, and, at approximately 160-190 nt, they are the smallest functional group I ribozymes known from nature. All GIR1s were found to contain a novel 6-bp pseudoknot (P15) within their catalytic core region. Experimental support of the proposed structure was obtained from the Didymium GIR1 by RNA structure probing and site-directed mutagenesis. Three-dimensional modeling indicates a compactly folded ribozyme with the functionally essential P15 exposed in the cleft between the two principal domains P3-P8 and P4-P6.

Antibody to granulocyte-macrophage colony-stimulating factor is a dominant anti-cytokine activity in human IgG preparations

Pharmaceutical preparations of normal human immunoglobulin (IgG) are known to contain high-avidity and neutralizing antibodies (Ab) to the cytokines interleukin (IL)-1alpha, IL-6, and interferon (IFN)alpha. To test for other cytokine Ab, 23 batches of IgG were tested for saturable binding to eight 125I-labeled recombinant cytokines. All batches bound granulocyte-macrophage colony-stimulating factor (GM-CSF) with high avidity (Kav approximately 10 pmol/L) and capacities of up to 5 mumol GM-CSF/mol IgG. Only 1 of 15 batches bound IL-5, also with high avidity, whereas 13 of 15 batches bound to IL-10 but with lower capacities and avidities. None of the IgG preparations bound IL-1 receptor antagonist (IL-1ra), IL-2, IL-3, IL-4, or G-CSF. Cross-binding and absorption analyses revealed identical or slightly stronger binding of recombinant GM-CSF, IL-5, and IL-10 than their native counterparts. GM-CSF-IgG complexes did not bind to cellular GM-CSF receptors, but Fc-dependent binding occurred to blood polymorphonuclear cells. Increased binding of GM-CSF to patient sera correlated positively with the binding capacities of infused IgG preparations. Patient and normal sera did not interfere with the binding of Ab to GM-CSF. From these and previous experiments, we conclude that pools of normal human IgG contain variable amounts of specific and high-avidity Ab to some cytokines, and that Ab to GM-CSF constitute a dominant anti-cytokine activity in these preparations. These Ab are available for reaction in vivo following IgG therapy.

Hen age and fatty acid composition of egg yolk lipid

1. Total lipid, total cholesterol, and phospholipid contents per gram of egg yolk were found to be the same for eggs from 21 and 57 week-old hens. 2. In contrast, fatty acid composition of total egg yolk lipid was different for the 2 groups of hens. The contents of long-chain (20 C and 22 C) polyunsaturated fatty acids of n-6 and n-3 series were 20% to 25% higher in egg yolks from the younger hens. 3. This finding is discussed with respect to the nutritional value of eggs from hens of different ages regarding the use of egg yolk lipid in the production of infant formulae.

Age-associated memory impairment--pathological memory decline or normal aging?

The aim of the study was to determine whether the memory capacity of individuals with age-associated memory impairment (AAMI) over a period of approximately 3 1/2 years declines more, if at all, than the memory capacity of persons without AAMI. Four computerized and three non-computerized memory tests, a naming test, and a test of visuo-motor speed were administered twice. Two estimates of intellectual capacity were made, one at the first examination and the other 3 1/2 years later. One person in the AAMI group (n = 44) developed vascular dementia. The group of AAMI subjects did less well on two of the seven memory tests after 3 1/2 years than they did initially; the control group (n = 18) had lower scores on one memory test at follow-up than they had previously. The data suggest that the memory capacity of subjects with AAMI is not pathologically impaired. The general intellectual level significantly influences whether an individual with memory complaints will be classified AAMI or not. People with high intelligence are less likely than people with lower intellectual capacity to fulfill the AAMI criteria. This suggests that AAMI lacks in construct validity.

Rat fetuin: distribution of protein and mRNA in embryonic and neonatal rat tissues

Fetuin is a serum protein widely distributed in the animal kingdom and found in all mammalian species so far investigated. It is mainly a fetal protein, in the sense that the highest concentrations are found in serum and body fluids of embryos and fetuses. In order to elucidate possible biological functions of fetuin, we have studied its synthesis and distribution during the prenatal development of the rat with immunohistochemistry and in situ hybridization. We have isolated fetuin from rat serum and produced an antibody against this protein. In situ hybridization was performed using a 375-nucleotides-long digoxigenin-labeled riboprobe. Fetuin was unevenly distributed in all organ systems during development, with the most pronounced expression at E 10Fetuin is a serum protein widely distributed in the animal kingdom and found in all mammalian species so far investigated. It is mainly a fetal protein, in the sense that the highest concentrations are found in serum and body fluids of embryos and fetuses. In order to elucidate possible biological functions of fetuin, we have studied its synthesis and distribution during the prenatal development of the rat with immunohistochemistry and in situ hybridization. We have isolated fetuin from rat serum and produced an antibody against this protein. In situ hybridization was performed using a 375-nucleotides-long digoxigenin-labeled riboprobe. Fetuin was unevenly distributed in all organ systems during development, with the most pronounced expression at E16-E18. Fetuin expression was present in germinal cell populations, e.g., in the basal layer in the skin, in the germinal cell populations in the brain anlage and the gonads, and it was heavily expressed in the fetal hemopoietic liver. Furthermore, fetuin was expressed in the gastrointestinal epithelium prior to the development of glands and crypts. Fetuin was widely distributed in mesenchymal derived tissues, e.g., bone and muscle. In the developing kidney fetuin was heavily expressed is both mesenchymal condensations and glomerular anlages. Thus, fetuin was located in cells or structures undergoing differentiation and transformation. As fetuin has been shown previously to interfere with hormone signaling of transforming growth factor-beta, insulin and hepatocyte-growth factor, fetuin might be involved in cell differentiation and tissue transformation during the initial histogenesis, i.e., the time period in which cellular phenotypic characteristics are established.

Intensive training, physiotherapy, or manipulation for patients with chronic neck pain. A prospective, single-blinded, randomized clinical trial

STUDY DESIGN

A randomized, prospective clinical study was conducted that included 119 patients with chronic neck pain of greater than 3 months' duration.

OBJECTIVES

To compare the relative effectiveness of intensive training of the cervical musculature, a physiotherapy treatment regimen, and chiropractic treatment on this patient group.

SUMMARY OF BACKGROUND DATA

There are only a few studies involving chronic neck pain patients representative of those seeking care in primary health care centers. Mobilization techniques and intensive training have been shown to be useful, but cervical manipulation has not been assessed. Clinical results involving these commonly used therapies have not been compared.

METHODS

A total of 167 consecutive patients were screened. One hundred nineteen patients were admitted to the study and were randomized according to Taves' minimization principles. Primary outcome measures included self-reported pain, disability, medication use, patients' perceived effect, and physician's global assessment. Patients were assessed at enrollment and at completion of the study. Postal questionnaires were used to carry out 4- and 12-month follow-up assessments. Secondary outcome measures included active range of motion of the cervical spine as well as strength and endurance measurements of the cervical musculature. These measurements were carried out at enrollment and completion of the study.

RESULTS

A total of 88% of the patients completed the study. Of these, 97% completed the 4-month questionnaire and 93% the 12-month questionnaire. Patients from all three groups demonstrated significant improvements regarding self-reported pain and disability on completion of the study. Improvements were maintained throughout the follow-up period. Medication use was also significantly reduced in all groups. There was, however, no significant difference between groups at any assessment period. Physician's and patients' assessments were also positive, and again group scores were essentially equal. Patients who underwent intensive training demonstrated significantly greater endurance levels at the completion of treatment.

CONCLUSIONS

There was no clinical difference between the three treatments. All three treatment interventions demonstrated meaningful improvement in all primary effect parameters. Improvements were maintained at 4- and 12-month follow-up. However, whether this was a result of the treatments or simply a result of time is unknown. Future studies will be necessary to delineate ideal treatment strategies.

Association of pulmonary surfactant protein A (SP-A) gene and respiratory distress syndrome: interaction with SP-B

Deficiency of the lipoprotein complex, surfactant, can lead to respiratory distress syndrome (RDS) in the prematurely born infant. The surfactant proteins (SP) play important roles in the function of surfactant. Previously, we have characterized four allelic variants of the SP-A1 gene (6A, 6A2, 6A3, and 6A4) and five allelic variants of the SP-A2 gene (1A, 1A0, 1A1, 1A2, and 1A3). We hypothesized that specific SP-A alleles/genotypes are associated with increased risk of RDS. Because race, gestational age (GA), and sex are risk factors for RDS, we first studied the distribution and frequencies of SP-A alleles/genotypes while adjusting for these factors as confounders or effect modifiers in control (n = 86 white and 12 black subjects) and RDS (n = 106 white and 37 black subjects) populations with GAs ranging from 24 wk to term. Although the odds ratios of several alleles and genotypes were in the opposite directions for black and white subjects, the homogeneity of odds ratio reached statistical significance only in the case of 6A3/6A3. Although differences were observed in subgroups with different GAs (< or =28 and >28 wk) of the RDS white population, definitive conclusions cannot be made regarding the effect of modification by GA. No differences were observed as a function of sex. Second, we compared the frequencies of SP-A genotypes and alleles between control (n = 83) and RDS (n = 82) patients in the >28-wk white population. Differences between the two groups were observed for the 1A0 allele and 1A0 genotypes. Moreover, a significant synergistic positive association was observed between 1A0 allele + SP-B polymorphic variant and RDS. We conclude that 1) the genetic analyses of RDS and SP-A locus should be performed separately for black and white populations and 2) SP-A alleles/genotypes and SP-B variant may contribute to the etiology of RDS and/or may serve as markers for disease subgroups.

Effect of genetic variation on the fatty acid-binding properties of human serum albumin and proalbumin

In the circulation, non-esterified fatty acids are transported by albumin which also facilitates their removal from donor cells and uptake into receptor cells. We have studied whether genetic variations in the albumin molecule can affect its in vivo fatty acid-binding properties. The fatty acids bound to 25 structurally different variants and to their wildtype counterparts, isolated from heterozygous carriers, were determined gas chromatographically. The variants were proalbumins, albumins with single amino acid substitutions and glycosylated or truncated albumins. In eight cases the total amount bound to the variants was diminished (0.4-0.8-fold), and in seven cases the load was increased to 1.3 or more of normal. Twenty-one fatty acids were quantitated, and for 19 alloalbumins significant deviations from normal were found. Usually, changes in total and individual fatty acid binding were of the same type, but several exceptions to this rule was found. The glycosylated albumin Casebrook showed the largest changes, the total load and the amount of bound palmitate was 8.6 and 14 times, respectively, the normal. The most pronounced changes and the majority of cases of increased binding were caused by molecular changes in domain III. Mutations in domain I, II and the propeptide resulted in smaller effects, if any, and these were often reductions in binding.

Neural network prediction of translation initiation sites in eukaryotes: perspectives for EST and genome analysis

Translation in eukaryotes does not always start at the first AUG in an mRNA, implying that context information also plays a role. This makes prediction of translation initiation sites a non-trivial task, especially when analysing EST and genome data where the entire mature mRNA sequence is not known. In this paper, we employ artificial neural networks to predict which AUG triplet in an mRNA sequence is the start codon. The trained networks correctly classified 88% of Arabidopsis and 85% of vertebrate AUG triplets. We find that our trained neural networks use a combination of local start codon context and global sequence information. Furthermore, analysis of false predictions shows that AUGs in frame with the actual start codon are more frequently selected than out-of-frame AUGs, suggesting that our networks use reading frame detection. A number of conflicts between neural network predictions and database annotations are analysed in detail, leading to identification of possible database errors.

A neural network method for identification of prokaryotic and eukaryotic signal peptides and prediction of their cleavage sites

We have developed a new method for the identification of signal peptides and their cleavage sites based on neural networks trained on separate sets of prokaryotic and eukaryotic sequences. The method performs significantly better than previous prediction schemes, and can easily be applied to genome-wide data sets. Discrimination between cleaved signal peptides and uncleaved N-terminal signal-anchor sequences is also possible, though with lower precision. Predictions can be made on a publicly available WWW server: http://www.cbs.dtu.dk/services/SignalP/.

Increased in vivo antibody activity against interferon alpha, interleukin-1alpha, and interleukin-6 after high-dose Ig therapy

High-avidity antibodies against interferon alpha (IFN alpha), interleukin-1alpha (IL-1alpha), and IL-6 have been demonstrated in preparations of normal human IgG, and in vivo modulation of these cytokines may therefore account for immunomodulatory and anti-inflammatory effects of high-dose intravenous IgG therapy. We have investigated the in vivo recovery and the effect on serum cytokine levels of antibodies to IFN alpha, IL-1alpha, and IL-6 infused with IgG preparations. Fifteen treatment series of 0.4 g IgG/kg/d were administered over 3 days to eight patients with autoimmune diseases. All IgG preparations contained variable amounts of antibodies binding to 125I-labeled human IFN alpha2A, -IL-1alpha, and -IL-6, and the contents of these molecules correlated with increased levels in serum anticytokine activities after IgG infusion. The infused anti-IL-1alpha antibody activity was fully recovered, whereas the recovery of anti-IFN alpha2A antibodies was significantly reduced. Serum antiviral activities were significantly reduced after IgG therapy (before, 0 to 5.6 IU/mL; after, 0 to 0.6 IU/mL). In contrast, enzyme-linked immunosorbent assay (ELISA) showed no significant reduction in the serum levels of IL-6 (before, 1 to 70 pg/mL; after, 2 to 55 pg/mL), and the levels of IL-1alpha were consistently below the detection limit (<30 pg/mL). In conclusion, increased levels of antibodies to IFN alpha2A, IL-1alpha, and IL-6 occurred in patients receiving IgG and this reduced the serum antiviral activity.

Prevalence of very mild to severe dementia in Denmark

OBJECTIVES

The prevalence of dementia has been estimated in several countries and a meta-analysis has shown moderate and severe dementia in people aged 65 years and older to be between 4% and 6%. The Odense study is aiming to estimate the prevalence and incidence of dementia and to identify risk factors.

MATERIAL AND METHODS

A total of 3346 persons, equivalent to 64.5% of a random sample of 5237 persons aged 65-84 years living in the municipality of Odense, Denmark, underwent a two phase diagnostic procedure including a screening with CAMCOG, the cognitive section of The Cambridge Examination for Mental Disorders of the Elderly, seven neuropsychological tests, medical examination, and CT scan. The severity of dementia was assessed by the CDR (Clinical Dementia Rating).

RESULTS

The prevalence rate was 7.1%, including the very mildly demented, defined as persons rated questionably demented according to the CDR scale. The prevalence rate of very mild dementia was 2.8%. The proportion of cases with very mild dementia decreased with increasing age while the prevalence rate increased.

CONCLUSION

Inclusion of very mild cases of dementia resulted in a higher prevalence rate than generally reported, and the prevalence rate increased exponentially with age which was mainly due to Alzheimer's disease.

[Continuing medical education via questionnaire studies. Three pilot projects for anesthesiology, cardiology and neurology]

The Danish Medical Association and the scientific societies have initiated three studies to evaluate the use of questionnaires for continuous medical education. One study was a questionnaire in anaesthesiology with 30 questions with answers yes/no/no answer, which was sent to 600 specialists in anaesthesiology. One study was in cardiology with a multiple choice questionnaire, sent to 300 general practitioners and 75 specialists in internal medicine outside cardiology. One study concerned the educational value of State-of-the-Art articles about neurology in Ugeskrift for Laeger (Journal of the Danish Medical Association) sent to 500 doctors outside neurology. All questionnaires were sent anonymously, with one general reminder. For the anaesthesiology study 234 questionnaires were returned (40.5%). In the cardiology study 195 questionnaires were returned (52%). For the study on neurology 278 answered (56%). Only about half of the questionnaires were returned for the three studies, and a lot of effort and resources were put into the studies. An extension from these small pilot studies to a general systematic continuous methodology with updated questionnaires in the postgraduate medical education seems troublesome. An optional self-registration for medical education such as The Canadian "Mocomp concept" might be a more realistic suggestion.

Identification of prokaryotic and eukaryotic signal peptides and prediction of their cleavage sites

We have developed a new method for the identification of signal peptides and their cleavage sites based on neural networks trained on separate sets of prokaryotic and eukaryotic sequence. The method performs significantly better than previous prediction schemes and can easily be applied on genome-wide data sets. Discrimination between cleaved signal peptides and uncleaved N-terminal signal-anchor sequences is also possible, though with lower precision. Predictions can be made on a publicly available WWW server.

Change in minimal cross sectional area using the new nasal dilator, "Airplus"

In 36 persons without nasal complaints nasal cavities were investigated using acoustic rhinometry (Rhin 2000), to study the effect of a nasal dilator (ND) named "Airplus". The minimal cross sectional area (MCA) of both the right and left side was assessed before and after application of the ND, and the total MCA was calculated as the sum of the right and left side. In 8 persons the MCA was measured before and after 2 applications of the ND. In 8 persons the MCA was measured before, immediately after and 2 hours after application of the ND. In trial one the median total MCA was 1.37 cm2 before and 1.96 cm2 after application of the ND. This corresponds to an increase of 43%, p < 0.000-01. In trial two the median total MCA was increased from 1.37 cm2 respectively 1.35 cm2 to 1.98 cm2 respectively 2.01 cm3, an increase of 45% respectively 49%, p < 0.008 in both. In trial three the median total MCA was 1.21 cm2 before and 1.95 cm2 immediately after application and 1.93 cm2 after 2 hours. The increase was 61 and 59%, p < 0.008 in both. The results show that the "Airplus" nasal dilator improves significantly the MCA, it was possible to reproduce the effect and it was stable in the recorded period.

Human SP-A locus: allele frequencies and linkage disequilibrium between the two surfactant protein A genes

Two surfactant protein A (SP-A) genes and several alleles for each SP-A locus have been previously described. In this report we investigate the potential usefulness of the SP-A loci as markers for genetic studies. We establish conditions that allow the identification of alleles with very similar sequences; We also determine the degree of polymorphism for each SP-A locus: The heterozygosity and polymorphism information content (PIC) values for the SP-A1 locus are 0.63 and 0.55, respectively, and for the SP-A2 locus are 0.50 and 0.56. In the course of these studies, we identify one new SP-A2 allele and show that the SP-A1 and SP-A2 loci are in linkage disequilibrium (P < 0.000001). We also identify 19 of the 20 possible haplotypes in a population of n = 239. Nine of the observed haplotypes reach statistical significance (P < 0.01) in this population, and the segregation of two haplotypes (6A2/1A0 and 6A4/1A) without recombination is verified in a family pedigree. These data together indicate that both SP-A loci are sufficiently polymorphic to be good markers for use in genetic studies. Furthermore, the finding of one novel allele suggests that additional unknown SP-A alleles are yet to be found.

Specific neutrophil hyporesponsiveness in chronic Helicobacter pylori infection

The release from mucosal neutrophils of reactive oxygen species (ROS) is believed to be an important part of the pathogenesis of Helicobacter pylori-associated gastritis and duodenal ulcer. In this study, bacterial sonicates prepared from 1 reference and 29 patient strains were used to stimulate ROS release from peripheral blood neutrophils. In 29 H. pylori-positive patients, the neutrophil response toward the homologous strain was absent. In contrast, a significant response was observed toward the reference strain. In addition, on stimulation of neutrophils from 29 patients without H. pylori infection, ROS release was significant. The stimulatory effect on neutrophils by FMLP was comparable in the 2 groups. It is concluded that a specific neutrophil hyporesponsiveness in ROS release toward the homologous R. pylori strain exists. This feature has, to our knowledge, not been described previously for neutrophil responses to any human pathogen.