Dehydroalanine crosslinks in human lens

This study was conducted to develop a methodology for the purification and detection of histidinoalanine, lanthionine and lysinoalanine in the lens tissue. Cataractous and aged human lens proteins were hydrolysed and fractionated by using anion-exchange chromatography. The fraction containing the bulk of dehydroalanine crosslinks was derivatized with dansyl chloride and then separated and quantified by means of RP-HPLC. The spectral and chromatographic properties of all three substances purified and quantified in this study were identical to those of their synthesized counterparts. Histidinoalanine and lanthionine were the most abundant dehydroalanine crosslinks in both water-soluble and water-insoluble lens proteins. Histidinoalanine levels in water-soluble proteins from the cataractous lenses of Indian origin were 6.2-fold higher than those in water-soluble proteins from normal lenses (1.68+/-0.75 vs 0.26+/-0.06 nmol/mg protein; p<0.001). In water-insoluble proteins, they were 2.2-fold higher in cataractous lenses compared with normal lenses (1.59+/-0.76 vs 0.73+/-0.17 nmol/mg protein; p<0.01). Lanthionine levels were significantly higher in water-insoluble proteins of cataractous lenses when compared to non-cataractous lenses (2.5+/-1.68 vs 0.95+/-0.08 nmol/mg protein; p<0.03). Unlike histidinoalanine, this crosslink appears to accumulate in relatively high concentrations in water-soluble lens proteins; its concentration was 9-fold higher than histidinoalanine from the same proteins (0.26+/-0.06 HAL vs 2.34+/-0.76 LAN nmol/mg protein; p<0.0004). The concentration of lysinoalanine was in the picomolar range and in cataractous lens proteins only.

Metamagnetic transition in Na 0.85 CoO2 single crystals

We report the magnetization, specific heat, and transport measurements of a high quality Na(0.85)CoO2 single crystal in applied magnetic fields up to 14 T. At high temperatures, the system is in a paramagnetic phase. It undergoes a magnetic phase transition below approximately 20 K. For the field H||c, the measurement data of magnetization, specific heat, and magnetoresistance reveal a metamagnetic transition from an antiferromagnetic state to a quasiferromagnetic state at about 8 T at low temperatures. However, no transition is observed in the magnetization measurements up to 14 T for H perpendicular c. The low temperature magnetic phase diagram of Na(0.85)CoO2 is determined.

Off-line separation and determination of rare earth elements associated with chloroplast pigments of hyperaccumulator Dicranopteris dichotoma by normal-phase liquid chromatography and ICP?MS

An off-line normal-phase liquid chromatography-ICP-MS method has been used for separation and determination of the rare earth elements (REE) associated with chloroplast pigments of Dicranopteris dichotoma. The stability of REE-bound pigments was tested, and almost no destruction of REE-bound pigments occurred during the so-called normal-phase liquid chromatography. The accumulated free REE ions on the microcrystalline cellulose column were cleaned by elution with 5 mmol L(-1) 2-ethylhexyl hydrogen 2-ethylhexylphosphonate (P507), to avoid exchange of these free ions with metals from the pigments. When these precautions were taken, the method was applied to the study of REE-bound pigments in D. dichotoma. ICP-MS results showed REE were present in chlorophylls and lutein, although REE concentrations in carotene and pheophytin were both below procedural blank levels. By careful analysis of the eluate fractions containing chlorophyll a it was found that REE-bound chlorophyll a in D. dichotoma was slightly enriched in the fractions with relatively short retention time. Results indicated that the retention time of REE-bound chlorophyll a might be slightly less than that of magnesium chlorophyll a, and REE-bound chlorophylls might be of relatively low polarity in comparison with magnesium bound chlorophylls. This phenomenon could be explained by the special double-decker sandwich-structure of REE-bound chlorophylls, as was reported by us and other authors. On the basis of these results we preferred to consider that REE can replace magnesium in chlorophyll a of D. dichotoma, and that the role of REE-bound chlorophylls in photosynthesis cannot be neglected. These data might be useful for understanding of both the properties of REE-bound pigments and the effect of REE on plant photosynthesis.

Identification of a novel human sand family protein in human fibroblasts induced by herpes simplex virus 1 binding

Studies on interaction between Herpes simplex virus 1 (HSV-1) and human fibroblasts KMB-17 have demonstrated that HSV-1 binding to the cell surface could induce a specific gene response. In this study, the HSV-1 stimulation-related gene 1 (HSRG1), a new so far unknown gene function of cellular response induced by a specific stimulation with HSV-1, was cloned from the cDNA library established from mRNA of early gene response of KMB-17 cells. The gene product consisted of 547 amino acids and had a significant homology, in six eukaryotic species. On the basis of its structure it was identified as a member of the SAND protein family. The HSRG1 protein was fused with glutathione S-transferase (GST) and expressed in Escherichia coli DHPalpha strain under the control of T7 promoter. An antibody to HSRG1 raised in mice was used to detect expression of the HSRG1 protein in KMB-17 cells stimulated by HSV-1 by an immunoprecipitation assay. It was found that the HSRG1 protein was induced in these cells by HSV-1 at high level.

[Studies on risk factors for liver fibrosis of schistosomiasis japonica]

OBJECTIVE

To explore the risk factors for schistosomal liver fibrosis.

METHODS

192 hepatitis-negative patients with schistosomiasis were selected and divided into 3 groups according to the result of B ultrasound examination, that is, grade 2 and 3 fibrosis group(81 patients), grade 1 fibrosis group (61 patients) and control group (non-fibrosis, 50 patiets). The univariate and multivariate ordinal regression model was made to analyse the possibly harmful factors influencing the liver damages of these patients.

RESULTS

Four factors were found to be positively associated with schistosomal liver fibrosis. They were: number of treatments of schistosomiasis (OR = 1.75), interval of schistosomal infection(OR = 1.40), history of drinking wine (OR = 1.95) and familial history of advanced schistosomiasis (OR = 2.11).

CONCLUSION

Patients with repeated schistosome infection, long duration of schistosomal infection, long history of drinking and familial history of advanced schistosomiasis had higher risk for liver fibrosis than schistosomiasis patients without these factors.

[Study on family aggregation of cases of advanced schistosomiasis japonica]

AIM

To explore the family aggregation of advanced schistosomiasis japonica.

METHODS

Eighty-one cases of advanced schistosomiasis(AS) and 67 cases of non-advanced schistosomiasis with history of infections in Yushan County, Jiangxi Province were chosen as proband groups and control groups respectively, then grades 1 and 2 relatives of them were investigated on AS. Family aggregation of AS was analyzed through comparing the prevalence rate between the close and distant relatives of probands and controls and fitting the observed distribution of AS cases among the population by zero-truncated Poisson distribution and zero-truncated negative binomial distribution.

RESULTS

The prevalence rate was higher in the close relatives (Group I relatives) of the probands than in the distant relatives(Group II relatives) of the probands and in the controls' relatives. The observed distribution of AS was beyond the probability of the zero-truncated Poisson distribution, but consistent with the zero-truncated negative binomial distribution.

CONCLUSION

Family aggregation of advanced schistosomiasis does exist.

[Effects and applications of ascorbic acid on the proliferation of Chlamydia trachomatis]

Two hundred and eighty-eight samples of patients with nongonococcal urethritis (NGU) and prostatitis were detected by cell culture and immunofluorescence assay for Chlamydia trachomatis (CT) and the effects of ascorbic acid(vitC) on the formation rate of inclusion of CT in positive samples were also studied. The results showed that the formation rate of inclusion of CT was 29.5% when the concentration of vitC was 5 micrograms.ml-1. The difference between test group and control group which contained cycloheximide in the media was insignificant (P > 0.05). The results suggested that vitC was a kind of nutrient needed for CT. The proliferation of CT in the cell can be promoted by vitC. We can replace cycloheximide by vitC in McCoy cell culture to detect clinic samples with CT.

[The prevalence and mechanism of Helicobacter pylori resistance to clarithromycin in Beijing]

OBJECTIVE

(1) To determine the prevalence of Helicobacter pylori strains resistant to clarithromycin in Peking. (2) To determine the genetic mutation in relation to clarithromycin resistance.

METHODS

Helicobacter pylori were cultured from gastric biopsies obtained from 89 patients during upper endoscopy. Minimal inhibitory concentrations of clarithromycin were determined by Etest method. Genomic DNA was prepared by the hexadecyltrimethylammonium bromide (CTAB)-phenol extraction method. Mutations in clarithromycin-resistant strains were identified by polymerase chain reaction and restrictions analysis.

RESULTS

(1) The prevalence of Helicobacter pylori strains resistant to clarithromycin was 13.5% in Beijing. (2) All twelve clarithromycin-resistant strains had the new BsaI site which is characteristic of the A2143G point mutation in 23S rRNA gene, none of the tested twenty-four susceptible strains had the A2142G or A2143G mutation.

CONCLUSION

The prevalence of clarithromycin-resistant strains was not rare in Beijing. Mutations in 23S rRNA are associated with clarithromycin resistance in Helicobacter pylori.

Regulation of the Bub2/Bfa1 GAP complex by Cdc5 and cell cycle checkpoints

During mitosis, a ras-related GTPase (Tem1) binds GTP and activates a signal transduction pathway to allow mitotic exit. During most of the cell cycle, Tem1 function is antagonized by a GTPase-activating protein complex, Bfa1/Bub2. How the Bfa1/Bub2 complex is regulated is not well understood. We find that Polo/Cdc5 kinase acts upstream of Bfa1/Bub2 in the mitotic exit network. Cdc5 phosphorylates Bfa1 and acts to antagonize Bfa1 function to promote mitotic exit. Bfa1 is regulated by multiple cell cycle checkpoints. The spindle assembly and spindle orientation checkpoints inhibit Bfa1 phosphorylation. DNA damage does not inhibit Bfa1 phosphorylation and instead causes a Rad53- and Dun1-dependent modification of Bfa1. Regulation of Bfa1 may therefore be a key step controlled by multiple checkpoint pathways to ensure a mitotic arrest.

Mrc1 transduces signals of DNA replication stress to activate Rad53

Cells experiencing DNA replication stress activate a response pathway that delays entry into mitosis and promotes DNA repair and completion of DNA replication. The protein kinases ScRad53 and SpCds1 (in baker's and fission yeast, respectively) are central to this pathway. We describe a conserved protein Mrc1, mediator of the replication checkpoint, required for activation of ScRad53 and SpCds1 during replication stress. mrc1 mutants are sensitive to hydroxyurea and have a checkpoint defect similar to rad53 and cds1 mutants. Mrc1 may be the replicative counterpart of Rad9 and Crb2, which are required for activating ScRad53 and Chk1 in response to DNA damage.

Lung tumor KRAS and TP53 mutations in nonsmokers reflect exposure to PAH-rich coal combustion emissions

We determined the TP53 and codon 12 KRAS mutations in lung tumors from 24 nonsmokers whose tumors were associated with exposure to smoky coal. Among any tumors studied previously, these showed the highest percentage of mutations that (a) were G --> T transversions at either KRAS (86%) or TP53 (76%), (b) clustered at the G-rich codons 153-158 of TP53 (33%), and (c) had 100% of the guanines of the G --> T transversions on the nontranscribed strand. This mutation spectrum is consistent with an exposure to polycyclic aromatic hydrocarbons, which are the primary component of the smoky coal emissions. These results show that mutations in the TP53 and KRAS genes can reflect a specific environmental exposure.

[Relation between infection of CagA-positive Helicobacter pylori and upper gastrointestinal diseases]

OBJECTIVE

To study the relation between infection of Helicobacter pylori strains expressing CagA and upper gastrointestinal diseases, and to assess the change of anti-CagA IgG antibody levels after eradication of H. pylori.

METHODS

Gastric biopsy was conducted among eight hundred and eight patients who received endoscopy to determine the pathological changes of mucosa and infectious status of H. pylori. The presence of serum anti-CagA IgG was detected in each H. pylori-positive patient by ELISA. Eradication therapy by PPI was conducted to the H. pylori-positive individuals. The anti-CagA IgG levels were reexamined among 60 patients whose H. pylori infection failed to be eradicated and 120 patients whose H. pylori infection was successfully eradicated after 3 months and 6 months.

RESULTS

The serum anti-CagA IgG-positive rates were 55.4%, 70.5%, 83.2%, 90.8% and 89.7% in H. pylori-positive patients with chronic superficial gastritis (CSG), chronic atrophic gastritis (CAG), gastric ulcer (GU), duodenal ulcer (DU), and gastric cancer (GC) respectively. The serum anti-CagA IgG-positive rates among the latter 4 groups were significantly higher than that in CSG group, and the serum anti-CagA IgG-positive rates among the latter 3 groups were significantly higher than that in CAG group. The serum anti-CagA IgG-positive rate among patients with CAG was significantly higher than that among patients with CSG (P < 0.05). The CagA-positive rates in the groups of intestinal metaplasia (IM), atypical hyperplasia and GC were significantly higher than those in the groups of CSG and CAG (P < 0.05). By the end of 3 and 6 months after the eradication therapy, the antibody level had decreased from a mean value of (69 +/- 38) U/ml to (47 +/- 30) U/ml and (32 +/- 15) U/ml among 120 patients with successful eradication and the serum antibody reverted to negative only in 23 cases from them. There was no significant change in serum anti-CagA IgG level among 60 patients without successful eradication.

CONCLUSION

Infection with CagA-positive H. pylori strains is associated with an increased risk of developing more severe gastroduodenal diseases and more severe gastric mucosa lesions. Despite an overall significant decrease of anti-CagA IgG level in sera after H. pylori eradication, this serological method cannot be used to monitor individual treatment effect because the anti-CagA IgG level decreases slowly.

Allergenic materials in the house dust of allergy clinic patients

INTRODUCTION

Environmental agents including animal, fungal, tree, and weed antigens are known to cause allergic rhinitis and asthma. The following study was performed to measure the antigen concentration of several of these in house dust of children seen in an allergy clinic. Comparisons are made between household allergen levels of children seen for asthma and children seen for other reasons.

METHODS

Dust samples were solicited from patients in a pediatric allergy specialty clinic and other individuals associated with the clinic. Persons submitting dust were asked to complete a questionnaire describing their house. Samples were extracted, centrifuged, and filtered for sterility. Samples were stored in 50% glycerol at -20 degrees C. Specific antigens for Alternaria, Cladosporium, Aspergillus, Candida, Dermatophagoides farinae, cat, dog, oak, fescue, ragweed, plantain, and cockroach were measured using inhibition assays developed with whole antigen extract. Allergens Der p1, Der f 1, Alt a 1, and Alt a 70 kD were measured using double monoclonal antibody assays.

RESULTS

Significant concentrations of whole antigen from cat, dog, oak, Alternaria, and Cladosporium were detected. Between 0.1 and 18 microg of Der f1 and Der p1 per gram of dust were also measured. Alt a 1 and Alt a 70 kD levels varied between 3.0 and 1000 U/g of dust. Significant positive correlations were observed in levels of dust mite and Alternaria allergen for patients with an evaluation of asthma.

CONCLUSIONS

We found measurable levels of fungal antigens (Alternaria, Cladosporium), mite antigens, and animal antigens (dog and cat) in the majority of dust samples in this self-selected set of allergy clinic patients. Specific allergens Alt a 1, Alt a 70kD, and Der p 1 were significantly higher in the homes of asthmatic patients when compared with patients seen for reasons other than asthma. These studies support the hypothesis that fungal allergen exposure is an important component in the pathogenesis of the clinical condition known as asthma.

Asf1 links Rad53 to control of chromatin assembly

Yeast defective in the checkpoint kinase Rad53 fail to recover from transient DNA replication blocks and synthesize intact chromosomes. The effectors of Rad53 relevant to this recovery process are unknown. Here we report that overproduction of the chromatin assembly factor Asf1 can suppress the Ts phenotype of mrc1rad53 double mutants and the HU sensitivity of rad53 mutants. Eliminating silencing also suppresses this lethality, further implicating chromatin structure in checkpoint function. We find that Asf1 and Rad53 exist in a dynamic complex that dissociates in response to replication blocks and DNA damage. Thus, checkpoint pathways directly regulate chromatin assembly to promote survival in response to DNA damage and replication blocks.

Prospective study of fat and protein intake and risk of intraparenchymal hemorrhage in women

BACKGROUND

-Dietary animal fat and protein have been inversely associated with a risk of intraparenchymal hemorrhage in ecological studies.

METHODS AND RESULTS

In 1980, 85 764 women in the Nurses' Health Study cohort, who were 34 to 59 years old and free of diagnosed cardiovascular disease and cancer, completed dietary questionnaires. From these questionnaires, we calculated fat and protein intake. By 1994, after 1.16 million person-years of follow-up, 690 incident strokes, including 74 intraparenchymal hemorrhages, had been documented. Multivariate-adjusted risk of intraparenchymal hemorrhage was higher among women in the lowest quintile of energy-adjusted saturated fat intake than at all higher levels of intake (relative risk [RR], 2.36; 95% CI, 1.10 to 5.09; P:=0.03). For trans unsaturated fat, the corresponding RR was 2.50 (95% CI, 1.35 to 4.65; P:=0.004). Animal protein intake was inversely associated with risk (RR in the highest versus lowest quintiles, 0.32; 95% CI, 0.10 to 1.00; P:=0.04). The excess risk associated with low saturated fat intake was observed primarily among women with a history of hypertension (RR, 3.66; 95% CI, 1.09 to 12.3; P=0.04), but such an interaction was not seen for trans unsaturated fat or animal protein. These nutrients were not related to risk of other stroke subtypes. Dietary cholesterol and monounsaturated and polyunsaturated fat were not related to risk of any stroke subtype.

CONCLUSIONS

Low intake of saturated fat and animal protein was associated with an increased risk of intraparenchymal hemorrhage, which may help to explain the high rate of this stroke subtype in Asian countries. The increased risk with low intake of saturated fat and trans unsaturated fat is compatible with the reported association between low serum total cholesterol and risk.

Hourly variation of airborne ragweed pollen in Kansas City

INTRODUCTION

Ragweed pollen is one of the major causes of allergic rhinitis in the midwest United States. Previous studies have demonstrated that ragweed pollen production begins after sunrise and airborne pollen levels peak several hours later. Variations in this pattern that may be of clinical importance within a small region and the effect of weather on these variations have not been investigated.

METHODS

Volumetric pollen collectors were stationed at four sites around the metropolitan area. Ten-minute grab samples were taken at each location every 2 hours for continuous 24-hour periods during the 1997 ragweed season. The downtown location had a weather station that logged meteorological conditions at hourly intervals during this time. Ragweed pollen grains were counted microscopically at 400 x. Uninterrupted data covering at least 20 days during the season were evaluated for each collection site.

RESULTS

The lowest ragweed pollen counts occur at 6:00 AM and the highest occur at noon for both suburban and urban sites. Rainfall was seen to be the most influential weather-related factor. Significant rainfall events effectively removed pollen grains from the air.

CONCLUSIONS

Though ragweed pollen emission begins at 6:00 AM, peak pollen exposure occurs at midday. This observation is in agreement with many other studies. The myth that highest ragweed exposure occurs in the early morning hours is not supported by this or previous studies.

A computationally simple test of homogeneity of odds ratios for twin data

It is of interest to compare measures of association of binary traits among samples of bivariate data. One example is the comparison of association within a sample of monozygotic (MZ) twins to that within a sample of dizygotic (DZ) twins. A larger association in the MZ twins suggests that the trait of interest may have a genetic component. The Bivariate data in this example are binary traits for the twins in each pair. Another example is the comparison of a measure of Hardy-Weinberg disequilibrium across several populations. The bivariate data in this example are the two alleles comprising the genotype of interest. We propose using derived logistic regression equations from the full exponential model for the bivariate outcomes to test for homogeneity. We adjust for correlation among outcomes via generalized estimating equations. This modeling approach allows for adjustment for individual-level and pair-level covariates and thereby allows for testing for gene x environment interactions. Further, we extend the model to allow for simultaneous analysis of two diseases, which allows for testing for a genetic component to the coaggregation of two diseases. In contrast to approaches proposed by previous authors, no special software is required; our approach can be easily implemented in standard software packages. We compare our results to those of other methods proposed in the literature for data from the Vietnam Era Twins Study. We apply our methods also to the Anqing Twin Study and to data on major depression and generalized anxiety disorder from the Virginia Twin Register.

[Surveillance of bacterial resistance in Shanghai]

OBJECTIVE

To analyze the surveillance data on bacterial resistance in Shanghai hospitals reported from January 1 to December 31, 1999.

METHODS

Data on bacterial susceptibility testings of 14 855 clinical isolates collected from eleven Shanghai hospitals were performed using Kirby-Bauer method and the results were analyzed according to NCCLS (1999).

RESULTS

Methicillin resistant strains accounted for 64% and 77% of S. aureus and CNS respectively; and no vancomycin resistant strains were found. In Enterococcus spp, vancomycin resistant strains accounted for 3.5% and 1.7% of E.fecalis and E.fecium, respectively. Resistant rates of E.coli against piperacillin, gentamicin and fluoroquinolones were about 50% or higher. Resistant rates of Klebsiella spp, Enterobacter spp, Citrobacter spp and Acinetobacter spp against the third generation cephalosporins have increased markedly. Besides, the resistant rates of P.aeruginosa against ceftazidime and imipenem have increased to 27% and 20% respectively.

CONCLUSION

A national strategy on the restrictive and prudent use of antibiotics is urgently needed.

Role of K(ATP)(+) channels in regulation of systemic, pulmonary, and coronary vasomotor tone in exercising swine

The role of ATP-sensitive K(+) (K(ATP)(+)) channels in vasomotor tone regulation during metabolic stimulation is incompletely understood. Consequently, we studied the contribution of K(ATP)(+) channels to vasomotor tone regulation in the systemic, pulmonary, and coronary vascular bed in nine treadmill-exercising swine. Exercise up to 85% of maximum heart rate increased body O(2) consumption fourfold, accommodated by a doubling of both cardiac output and body O(2) extraction. Mean aortic pressure was unchanged, implying that systemic vascular conductance (SVC) also doubled, whereas pulmonary artery pressure increased almost in parallel with cardiac output, so that pulmonary vascular conductance (PVC) increased only 25 +/- 9% (both P < 0.05). Myocardial O(2) consumption tripled during exercise, which was paralleled by an equivalent increase in O(2) supply so that coronary venous PO(2) was maintained. Selective K(ATP)(+) channel blockade with glibenclamide (3 mg/kg iv), decreased SVC by 29 +/- 4% at rest and by 10 +/- 2% at 5 km/h (both P < 0.05), whereas PVC was unchanged. Glibenclamide decreased coronary vascular conductance and hence myocardial O(2) delivery, necessitating an increase in O(2) extraction from 76 +/- 2% to 86 +/- 2% at rest and from 79 +/- 2% to 83 +/- 1% at 5 km/h. Consequently, coronary venous PO(2) decreased from 25 +/- 1 to 17 +/- 1 mmHg at rest and from 23 +/- 1 to 20 +/- 1 mmHg at 5 km/h (all values are P < 0.05). In conclusion, K(ATP)(+) channels dilate the systemic and coronary, but not the pulmonary, resistance vessels at rest and during exercise in swine. However, opening of K(ATP)(+) channels is not mandatory for the exercise-induced systemic and coronary vasodilation.