Endotoxin Levels in Rural Thai and Urban Singaporean Homes

BACKGROUND

Exposure to dust endotoxin and allergens in early childhood may influence the development of allergic diseases.

AIMS

This study aimed to evaluate dust endotoxin and dust mite allergens in urban Singapore and rural Thai homes of young children and study potential environmental influences.

METHODS

Mattress dust endotoxin and Der p 1, Der f 1, group 2 (Der f 2 and Der p 2) and Blo t 5 allergen levels were quantified in 101 infant mattress dust samples, 51 from urban Singapore and 50 from rural Thailand. Comprehensive questionnaires on the home environment and cleaning practices were completed.

RESULTS

Endotoxin levels in rural Thailand were significantly higher than in urban Singapore (geometric mean 26,334.12 +/- 4.60 and 18,377.85 +/- 2.52 endotoxin units/g, respectively; p = 0.032). In contrast, higher levels of Der f 1 (p = 0.02), group 2 (p < 0.01) and Blo t 5 (p < 0.01) allergens were found in Singapore homes compared with rural Thai homes. Multiple logistic regression analysis showed that the use of detergents (p = 0.001) and disinfectants (p = 0.024) to clean floors and mattress protectors (p = 0.021) were independently associated with lower endotoxin levels.

CONCLUSION

Endotoxin levels are higher in rural compared with urban homes in South East Asia. The reverse was true for dust mite allergen levels. Certain identifiable home environmental conditions and practices accounted for the differences in endotoxin levels.

The specificity of Sushi peptides for endotoxin and anionic phospholipids: potential application of POPG as an adjuvant for anti-LPS strategies

Sushi peptides [S1 (Sushi 1 peptide) and S3] are derived from the LPS (lipopolysaccharide; also known as endotoxin)-binding domains of an LPS-sensitive serine protease, Factor C, from the horseshoe crab (Carcinoscorpius rotundicauda). S1 and S3 interact at high affinity with LPS. The intermolecular disulphide bonding in the S3 dimer is indispensable for its LPS binding, disruption and consequent neutralization. Simultaneously, the specific interaction between the Sushi peptides and bacterial membrane phospholipids further explains the selective propensity of these peptides for the gram-negative bacteria. Our findings yield insights into a complex molecular paradigm in which the juxtaposition of LPS molecules and the anionic phospholipid POPG (1-palmitoyl-2-oleoyl phosphatidylglycerol) on the bacterial outer membrane confers such interfacial properties which create the optimal environment for the interaction between the peptides and bacterial membrane lipids.

Spatial and temporal coordination of expression of immune response genes during Pseudomonas infection of horseshoe crab, Carcinoscorpius rotundicauda

Knowledge on how genes are turned on/off during infection and immunity is lacking. Here, we report the co-regulation of diverse clusters of functionally related immune response genes in a horseshoe crab, Carcinoscorpius rotundicauda. Expressed sequence tag (EST) clusters for frontline immune defense, cell signalling, apoptosis and stress response genes were expressed or repressed spatio-temporally during the acute phase of Pseudomonas infection. An infection time course monitored by virtual Northern evaluation indicates upregulation of genes in blood cells (amebocytes) at 3-h postinfection, whereas most of the hepatopancreas genes remained down regulated over 72 h of infection. Thus, the two tissues orchestrate a coordinated and timely response to infection. The hepatopancreas probably immuno-modulates the expression of other genes and serves as a reservoir for later response, if/when chronic infection ensues. On the other hand, being the first to encounter pathogens, we reasoned that amebocytes would respond acutely to infection. Besides acute transactivation of the immune genes, the amebocytes maintained morphological integrity, indicating their ability to synthesise and store/secrete the immune proteins and effectors to sustain the frontline innate immune defense, while simultaneously elicit complement-mediated phagocytosis of the invading pathogen. Our results show that the immune response against Pseudomonas infection is spatially and temporally coordinated.

De novo design of potent antimicrobial peptides

Lipopolysaccharide (LPS), shed by gram-negative bacteria during infection and antimicrobial therapy, may lead to lethal endotoxic shock syndrome. A rational design strategy based on the presumed mechanism of antibacterial effect was adopted to design cationic antimicrobial peptides capable of binding to LPS through tandemly repeated sequences of alternating cationic and nonpolar residues. The peptides were designed to achieve enhanced antimicrobial potency due to initial bacterial membrane binding with a reduced risk of endotoxic shock. The peptides designed displayed binding affinities to LPS and lipid A (LA) in the low micromolar range and by molecular modeling were predicted to form amphipathic beta-hairpin-like structures when they bind to LPS or LA. They also exhibited strong effects against gram-negative bacteria, with MICs in the nanomolar range, and low cytotoxic and hemolytic activities at concentrations significantly exceeding their MICs. Quantitative structure-activity relationship (QSAR) analysis of peptide sequences and their antimicrobial, cytotoxic, and hemolytic activities revealed that site-directed substitutions of residues in the hydrophobic face of the amphipathic peptides with less lipophilic residues selectively decrease the hemolytic effect without significantly affecting the antimicrobial or cytotoxic activity. On the other hand, the antimicrobial effect can be enhanced by substitutions in the polar face with more polar residues, which increase the amphipathicity of the peptide. On the basis of the QSARs, new analogs that have strong antimicrobial effects but that lack hemolytic activity can be proposed. The findings highlight the importance of peptide amphipathicity and allow a rational method that can be used to dissociate the antimicrobial and hemolytic effects of cationic peptides, which have potent antimicrobial properties, to be proposed.

Effectiveness ofCyanothece spp. andCyanospira capsulata exocellular polysaccharides as antiadhesive agents for blocking attachment ofHelicobacter pylori to human gastric cells

The effect of cyanobacterial polysaccharides (from Cyanothece spp. and Cyanospira capsulata) on the binding of Helicobacter pylori to gastric epithelial cells was evaluated. The antiadhesive action on Kato III and HeLa S3 human gastric cell lines was established.

Unwanted effects of morphine-6-glucoronide and morphine

The active metabolite of morphine, morphine-6-glucuronide (M6G), may have fewer unwanted effects than morphine. We randomly allocated 144 women to receive either M6G or morphine as part of general anaesthesia for day case gynaecological laparoscopy. The incidence of nausea, vomiting, pain, sedation and skin rash, and severity of nausea, pain and sedation after surgery were recorded by direct observation in hospital, and by questionnaire until the next morning. Compared with the M6G group, patients who received morphine were more likely to report nausea in the first 2 h after surgery (odds ratio 2.9, CI 1.31-6.21) and to suffer it with greater severity. During the same time period, they were more likely to vomit and feel sleepy, but the intensity of pain and use of rescue analgesics were similar in both groups. The incidences of nausea, vomiting and the feeling of sleepiness continued to be greater in the morphine group during and after the journey home. The next morning, patients in the morphine group remained sleepier, but the incidence of nausea was similar for the two groups. M6G appears to have a better toxicity profile than morphine. More efficacy studies are needed to define accurately the analgesic potency of systemically administered M6G.

Acute pain services in Hong Kong: facilities, volume, and quality

Acute pain services in public hospitals in Hong Kong were studied. Audit data on the volume and quality of acute pain services were collected prospectively from 1997 to 1999, and data on related facilities were collected in 2000. About 20% of patients undergoing a major operation received an acute pain service; of these, 78.6% were satisfied with the treatment provided. In 2000, 86% (18/21) of hospitals providing anaesthetic services were running an acute pain service. Staffing was better in hospitals providing a high volume of acute pain services, ranging from a full-time specialist anaesthesiologist assisted by a half-time trainee to a half-time specialist assisted by a full- or half-time trainee. However, only four hospitals were staffed with pain nurses. In total, 57% of patients received intravenous patient-controlled analgesia and 32% epidural analgesia. The mean duration of acute pain service treatment was 3.1 days. Currently anaesthesiologist-based acute pain services take care of a limited number of patients. To expand the coverage, there should be a move towards an anaesthesiologist-led, pain nurse-based, acute pain service. The present shortage of pain nurses should be addressed.

High therapeutic index of factor C Sushi peptides: potent antimicrobials against Pseudomonas aeruginosa

Factor C protein isolated from the horseshoe crab, Carcinoscorpius rotundicauda, has endotoxin binding capability. Synthetic peptides of 34 amino acids based on the sequence of two regions of factor C (Sushi 1 and Sushi 3) as well as their corresponding mutants exhibited activities against 30 clinical isolates of Pseudomonas aeruginosa. Collectively, all four peptides demonstrated exceptionally effective bactericidal activity against P. aeruginosa with 90% minimal bactericidal concentrations (MBC(90)s) in the range of 0.06 to 0.25 microg/ml (16 to 63 nM). Viable bacteria were reduced by 90% after 7 min and were totally eradicated within 40 to 50 min. These peptides are minimally hemolytic against both rabbit and human erythrocytes even at concentrations up to 1,600-fold their MBC(90)s. Both in vitro and in vivo studies indicate that cytotoxic effects are small even at 1,000-fold their MBC(90)s. Furthermore, the Sushi peptides are tolerant of high-salt and adverse pH conditions. These findings demonstrate the promising therapeutic potential of the Sushi peptides.

Anaesthetic clinical indicators in public hospitals providing anaesthetic care in Hong Kong: prospective study

OBJECTIVES

To assess the quality of anaesthetic services as defined in the six anaesthetic clinical indicators against preset standards and to identify risk factors for adverse events in the recovery room.

DESIGN

Prospective study.

SETTING

All public hospitals providing anaesthetic care in Hong Kong.

PATIENTS

Eighteen thousand, seven hundred and fifty-nine patients receiving elective or emergency anaesthesia administered by anaesthetists from June 1998 to July 1998.

MAIN OUTCOME MEASURES

Patient demographics, American Society of Anesthesiologists status, category and nature of operation, presence of preoperative anaesthetic visit in ward, type of anaesthesia, reasons for a recovery room stay of more than a 2-hour duration, intubation to relieve respiratory distress in the recovery room, presence of hypothermia in the recovery room for operations lasting more than 2 hours, and dental or ocular injuries attributable to anaesthesia.

RESULTS

There are two major findings from this study. Firstly, a high incidence of hypothermia in the recovery room was reported. Secondly, a greater risk of prolonged stay in the recovery room was identified for patients older than 65 years, major operations, and anaesthetic techniques using combined general and regional anaesthesia.

CONCLUSION

The six anaesthetic clinical indicators reflected the provision of anaesthetic care in public hospitals in Hong Kong. Good compliance to the preset standard of the anaesthetic clinical indicators was achieved during the study period.

High-performance affinity capture-removal of bacterial pyrogen from solutions

Synthetic peptide S3delta has high affinity for bacterial endotoxin or lipopolysaccharide (LPS). Under tested conditions of pH 5-9 and 0-0.4 M NaCl, the affinity constant, KD ranged from 2.10(-6) to 2 x 10(-9) M(-1). A novel affinity matrix based on peptide S3delta was developed for removal of LPS from solutions such as: water; buffers with a wide range of ionic strength and pH; medium for cell culture; and protein solutions under optimized conditions. At a starting LPS of approximately 100 EU/ml, a post-purification level below 0.005 EU/ml was achieved.

Efficacy of a nitroimidazole containing tripletherapy regime in Singapore

BACKGROUND

There has been a gradual increase in the proportion of Singapore patients with metronidazole resistant strains of Helicobacter pylori. We studied the efficacy of a nitroimidazole containing regime in eradicating H. pylori.

METHODS

Consecutive treatment naive patients with peptic ulcer disease and culture proven H. pylori were recruited. From each patient, two antral biopsies were taken for rapid urease test and two for histology. Two biopsies each from the gastric antrum and corpus were taken for H. pylori culture. Antibiotic sensitivity to amoxycillin, metronidazole, clarithromycin and tetracycline were tested using the disc diffusion method. Patients were treated with lansoprazole 30 mg bd, tinidazole 500 mg bd and clarithromycin 500 mg bd for seven days. Successful eradication was defined as either negative urea breath tests 4 and 12 weeks after treatment, or negative histology and culture at least four weeks after the end of treatment.

RESULTS

A total of 64 patients were culture positive (51 males, 13 females). Forty-two patients had duodenal ulcers (DU), 17 gastric ulcers (GU), and 5 DU and GU. Metronidazole resistance was detected in 16 patients (25%). Three of the 16 patients (19%) had a mixed population of resistant and sensitive strains of H. pylori. None of the H. pylori isolates were resistant to amoxycillin, tetracycline or clarithromycin. Overall, eradication was achieved in 51/64 patients (80%). Eradication rate was 88% (42/48) among those with metronidazole sensitive strains, and 56% (9/16) among those with metronidazole resistant strains (p < 0.02).

CONCLUSION

A high proportion of our patients with metronidazole resistant strains of H. pylori failed eradication therapy when a nitroimidazole containing regime was used. It may not be appropriate to use a nitroimidazole containing without prior knowledge of the antibiotic sensitivity pattern of the H. pylori isolate.

Synthesis and structure-activity relationships of potential anticonvulsants based on 2-piperidinecarboxylic acid and related pharmacophores

Using N-(2,6-dimethyl)phenyl-2-piperidinecarboxamide (1) and N-(alpha-methylbenzyl)-2-piperidinecarboxamide (2) as structural leads, a variety of analogues were synthesised and evaluated for anticonvulsant activity in the MES test in mice. In the N-benzyl series, introduction of 3-Cl, 4-Cl, 3,4-Cl2, or 3-CF3 groups on the aromatic ring led to an increase in MES activity. Replacement of the alpha-methyl group by either i-Pr or benzyl groups enhanced MES activity with no increase in neurotoxicity. Substitution on the piperidine ring nitrogen led to a decrease in MES activity and neurotoxicity, while reduction of the amide carbonyl led to a complete loss of activity. Movement of the carboxamide group to either the 3- or 4-positions of the piperidine ring decreased MES activity and neurotoxicity. Incorporation of the piperidine ring into a tetrahydroisoquinoline or diazahydrinone nucleus led to increased neurotoxicity. In the N-(2,6-dimethyl)phenyl series, opening of the piperidine ring between the 1- and 6-positions gave the active norleucine derivative 75 (ED50=5.8 mgkg(-1), TD50 =36.4 mgkg(-1), PI=6.3). Replacement of the piperidine ring of 1 by cycloalkane (cyclohexane, cyclopentane, and cyclobutane) resulted in compounds with decreased MES activity and neurotoxicity, whereas replacement of the piperidine ring by a 4-pyridyl group led to a retention of MES activity with a comparable PI. Simplification of the 2-piperidinecarboxamide nucleus of 1 into a glycinecarboxamide nucleus led to about a six-fold decrease in MES activity. The 2,6-dimethylanilides were the most potent compounds in the MES test in each group of compounds evaluated, and compounds 50 and 75 should be useful leads in the development of agents for the treatment of tonic-clonic and partial seizures in man.

Helicobacter pylori in familial clusters based on antibody profile

Studies have shown a high prevalence of Helicobacter pylori infection in close communities and that intrafamilial spread during early childhood may be a route of transmission. A total of 72 household members from 21 families were enrolled in this study. Sera from individuals showed 50/72 (69.4%) seropositive for IgG against H. pylori by ELISA. Western blots showed diversity in the protein profiles with molecular masses ranging from approximately 8 to 130 kDa. Cohen's kappa statistical analysis of the blot patterns showed that nine families demonstrated similar profiles (100%), while 4 other families showed varying similarities (17-50%). The results support the hypothesis of intrafamilial transmission of H. pylori. Furthermore, serological studies can be used as an effective approach to determine the familial status in relation to H. pylori infection.

The status of the cagA gene does not predict Helicobacter pylori-associated peptic ulcer disease in Singapore

Discrepancies among reports from different geographical regions worldwide on the association between the presence of cagA and peptic ulcer disease prompted this study on the predictive value of the cagA gene in Helicobacter pylori-associated gastroduodenal diseases in the Singapore population. H. pylori strains were obtained from 169 patients with a peptic ulcer, 83 with non-ulcer dyspepsia, and nine with gastric cancer. The presence of the cagA gene was evaluated by polymerase chain reaction (PCR). The expected 400 bp PCR product coding for the cagA gene was present in 232/261 (89%) H. pylori isolates. Of these, 151/169 (89%) strains from patients with peptic ulcer, 73/83 (88%) strains from patients with non-ulcer dyspepsia and 8/9 (89%) strains from cancer patients were positive for the cagA gene. There was no statistically significant difference between the prevalence of cagA-positive strains from patients with distinct clinical outcomes (p > 0.05). The prevalence of cagA-positive strains in the Singapore population is high regardless of clinical disease status. The results suggest that the cagA gene is not a universal virulence marker of H. pylori.

Substance P immunoreactive sensory axons as a subset of the total axonal population in the maxillary sinus of the rabbit: a characterization of normal and infected mucosa

Substance P (SP), one of the neuropeptides released from sensory nerves, is thought to mediate neurogenic inflammation. Although SP immunoreactive axons have been described in the sinus mucosa, no attempt has been made to characterize SP fibers as a subset of all axons present in the sinus mucosa. In addition, no study to date has characterized the changes in infected sinus mucosa. The maxillary sinus mucosa of New Zealand white rabbits was harvested from control animals and in animals with induced maxillary sinusitis. Immunohistochemical staining of the sinus mucosa for both Protein Gene Product 9.5 (PGP), a nonspecific marker for all nerves, and for SP was performed on 11 animals: 3 controls and 8 infected. In sinus mucosa from the control rabbits, <50% of all axons labeled by PGP were immunoreactive for SP. In infected mucosa, the absolute number of axons found by PGP staining decreased and nearly all of these remaining fibers were also immunoreactive for SP. We conclude that the phenotypical labeling of nerve fibers seen in normal mucosa is altered by bacterial-induced infection.

Accurate diagnosis of Helicobacter pylori. Serologic testing

Serologic testing is a useful noninvasive testing strategy for H. pylori. It is particularly useful in areas where the prevalence of H. pylori is high and inexpensive point-of-contact fingerprick tests are used. Sensitive tests are valuable ways of excluding H. pylori infection and can be used in conjunction with a direct test (urease histology culture or breath test) to confirm absence of H. pylori if the two methods are concordant. Serologic testing is more definitive and differentiating if the antigenic epitopes of H. pylori can be differentiated based on the antigenic epitopes that specifically associate with gastric cancer, peptic ulcer, and nonulcer dyspepsia. A study by Kawahara's group reported that Hsp 60 may be involved in the development of mucosa-associated lymphoid tissue based on ELISA. The idea of differentiating antigens for H. pylori may open a new area for use of serologic testing in the diagnostic approach of H. pylori infections.

Increasing frequency of dental patients in the urban ED

This study examined the spectrum and frequency of dental disorders presenting to an urban ED. Data were retrospectively collected on all patients presenting with dental complaints between January 1, 1987 and December 31, 1995. Data included age, date and time of presentation, diagnosis, triage acuity and disposition. Of the 3,943 charts reviewed, 1,892 (48%) patients required emergent oral surgery management and 2,051 (52%) emergency physician management only. The frequency of dental patients increased from 4.4/1,000 total ED patients in 1987 to 11.5/1,000 in 1995 (P < .05). The rate of emergent dental trauma, emergent nontraumatic dental care, and nonemergent nontraumatic dental care increased similarly during the study period. There was no significant difference by day of week, but a significantly greater number of nonemergent patients presented between 7:00 a.m. and 3:00 p.m. (72%). The incidence of dental patients presenting to the ED increased significantly between 1987 and 1995. Approximately one-half did not require specialist consultation and could potentially have been managed by a primary care dental practitioner.

Isolation of a single strain of Helicobacter pylori from the antrum and body of individual patients

OBJECTIVES

This study aimed to determine intra-patient colonization patterns of Helicobacter pylori strains based on DNA fingerprinting and antibiotic susceptibility.

METHODS

Two biopsies, one from the antrum and one from the body of the stomach, were taken from 97 patients. Prior informed consent was obtained. The status of cagA gene of H. pylori strains was analysed by using the polymerase chain reaction (PCR) technique, while DNA fingerprints were generated by PCR-based, random amplified polymorphic DNA (RAPD) fingerprinting. The antibiotic susceptibility of the H. pylori isolates was examined by the disk diffusion method.

RESULTS

A total of 51 pairs of H. pylori strains were isolated from both antrum and body specimens of 51 patients. This included two patients who were endoscoped twice because of treatment failure. All strains were positive for cagA gene by PCR. These 51 patients were found to harbour a single strain of H. pylori with identical or highly similar DNA profiles by PCR-based RAPD fingerprinting. In four of the 51 pairs, the DNA patterns of H. pylori from antrum and body showed minor differences, while three pairs of strains with different metronidazole sensitivities showed identical DNA fingerprints. Interestingly, the two treatment failure patients remained colonized with the strains that had the same RAPD fingerprinting patterns before and after treatment.

CONCLUSION

The present study demonstrates that a single H. pylori strain colonizes a single stomach. However, this single genotypic strain may exhibit different metronidazole susceptibility in different parts of stomach.

Definition of endotoxin binding sites in horseshoe crab factor C recombinant sushi proteins and neutralization of endotoxin by sushi peptides

Three truncated fragments, harboring different sushi domains, namely, sushi123, sushi1, and sushi3 domains, of Factor C were produced as biologically active secreted recombinant proteins. Sushi1 and 3 each has a high-affinity LPS binding site with K:(d) of 10(-9) to 10(-10) M. Positive cooperativity in sushi123 resulted in a 1000-fold increase in K:(d)2. The core LPS binding region of sushi1 and 3 reside in two 34-mer peptides, S1 and S3. A rigidly held disulfide-bonded structure is not essential but is important for LPS binding, as confirmed by a 100- to 10000-fold decrease in affinity. Both S1 and S3 can inhibit LAL reaction and LPS-induced hTNF-alpha secretion with different potency. LAL assay revealed that at least two molecules of S1 bind cooperatively to one LPS molecule, with Hill's coefficient of 2.42. The LPS binding by S3 is independent and noncooperative. The modified SDelta1 and SDelta3 peptides exhibited increased LPS neutralization potential although its LPS binding affinities indicated only a 10-fold improvement. Hence, the structural difference of the four sushi peptides conferred different efficiencies in LPS neutralization without altering their binding affinity for LPS. Circular dichroism spectrometry revealed that the four peptides underwent conformational change in the presence of lipid A, transitioning from a random coil to either an alpha-helical or beta-sheet structure. Two factors are critical for the sensitivity of Factor C to LPS: 1) the presence of multiple binding sites for LPS on a single Factor C molecule; and 2) high positive cooperativity in LPS binding. The results showed that in the design of an improved LPS binding and neutralizing peptide, charge balance of the peptide is a critical parameter in addition to its structure.

Association of peptic ulcer with increased expression of Lewis antigens but not cagA, iceA, and vacA in Helicobacter pylori isolates in an Asian population

BACKGROUND

Studies in Western populations suggest that cagA, iceA, and vacA gene status in Helicobacter pylori isolates is associated with increased virulence and peptic ulcer disease.

AIM

To investigate the relationship between peptic ulcer and expression of Lewis (Le) antigens as well as cagA, iceA, and vacA in H pylori isolates in Singapore.

METHODS

Expression of Le antigens in H pylori isolates obtained from patients with dyspepsia was measured by enzyme linked immunosorbent assay. The cagA, iceA, and vacA status was determined by polymerase chain reaction.

RESULTS

Of 108 H pylori isolates, 103 (95.4%) expressed Le(x) and/or Le(y), while Le(a) and Le(b) were expressed in 23 (21.3%) and 47 (43.5%) isolates, respectively. Expression of two or more Le antigens (Le(x), Le(y), Le(a), or Le(b)) was significantly higher in H pylori isolated from ulcer patients than in non-ulcer patients (89.6% v 73.2%, p=0.035). There were no significant differences in the prevalence of cagA or iceA1 in H pylori isolates from peptic ulcer and non-ulcer patients (86.6% v 90.2% for cagA; 70.1% v 68.3% for iceA1), and no association of peptic ulcer with any specific vacA genotype.

CONCLUSIONS

The present study indicates that peptic ulcer disease is associated with increased expression of Lewis antigens but not cagA, iceA, or vacA genotype in H pylori isolates in our population. This suggests that cagA, iceA, and vacA are not universal virulence markers, and that host-pathogen interactions are important in determining clinical outcome.

Expression of histo-blood group antigens by lipopolysaccharides of Helicobacter pylori strains from asian hosts: the propensity to express type 1 blood-group antigens

Past studies have shown that the cell surface lipopolysaccharides (LPSs) of the ubiquitous human gastric pathogen Helicobacter pylori (a type 1 carcinogen) isolated from people residing in Europe and North America express predominantly type 2 Lewis x (Le(x)) and Le(y) epitopes and, infrequently, type 1 Le(a), Le(b), and Le(d) antigens. This production of Lewis blood-group structures by H. pylori LPSs, similar to those found in the surfaces of human gastric cells, allows the bacterium to mimic its human niche. In this study, LPSs of H.pylori strains extracted from patients living in China, Japan, and Singapore were chemically and serologically analyzed. When compared with Western H.pylori LPSs, these Asian strains showed a stronger tendency to produce type 1 blood groups. Of particular interest, and novel observations in H.pylori, the O-chain regions of strains F-58C and R-58A carried type 1 Le(a) without the presence of type 2 Le(x), strains R-7A and H607 were shown to have the capability of producing the type 1 blood group A antigen, and strains CA2, H507, and H428 expressed simultaneously the difucosyl isomeric antigens, type 1 Le(b) and type 2 Le(y). The apparent proclivity for the production of type 1 histo-blood group antigens in Asian H.pylori LPSs, as compared with Western strains, may be an adaptive evolutionary effect in that differences in the gastric cell surfaces of the respective hosts might be significantly dissimilar to select for the formation of different LPS structures on the resident H.pylori strain.