Delineating family needs in the transition from hospital to home for children with medical complexity: part 1, a meta-aggregation of qualitative studies.

BACKGROUND: Advances in diagnostic and therapeutic interventions for rare diseases result in greater survival rates, with on the flipside an expanding group of children with medical complexity (CMC). When CMC leave the protective hospital environment to be cared for at home, their parents face many challenges as they take on a new role, that of caregiver rather than care-recipient. However, an overview of needs and experiences of parents of CMC during transition from hospital-to-home (H2H) is lacking, which hampers the creation of a tailored H2H care pathway. Here we address this unmet medical need by performing a literature review to systematically identify, assess and synthesize all existing qualitative evidence on H2H transition needs of CMC parents. METHODS: An extensive search in Medline, PsychINFO and CINAHL (up to September 2022); selection was performed to include all qualitative studies describing parental needs and experiences during H2H transition of CMC. All papers were assessed by two independent investigators for methodological quality before data (study findings) were extracted and pooled. A meta-aggregation method categorized the study findings into categories and formulated overarching synthesized findings, which were assigned a level of confidence, following the ConQual approach. RESULTS: The search yielded 1880 papers of which 25 met eligible criteria. A total of 402 study findings were extracted from the included studies and subsequently aggregated into 50 categories and 9 synthesized findings: (1) parental empowerment: shifting from care recipient to caregiver (2) coordination of care (3) communication and information (4) training skills (5) preparation for discharge (6) access to resources and support system (7) emotional experiences: fatigue, fear, isolation and guilt (8) parent-professional relationship (9) changing perspective: finding new routines and practices. The overall ConQual Score was low for 7 synthesized findings and very low for 2 synthesized findings. CONCLUSIONS: Despite the variability in CMC symptoms and underlying (rare disease) diagnoses, overarching themes in parental needs during H2H transition emerged. We will augment this new knowledge with an interview study in the Dutch setting to ultimately translate into an evidence-based tailored care pathway for implementation by our interdisciplinary team in the newly established 'Jeroen Pit Huis', an innovative care unit which aims for a safe and sustainable H2H transition for CMC and their families.

A historic cohort study of nutritional status related side effects and weight loss of cancer patients treated with immunotherapy.

BACKGROUND AND AIMS: Recently, there has been an increase in the number of patients treated with immunotherapy. However, the number of studies investigating combination immunotherapies is still limited, resulting in a gap of knowledge regarding the incidence of nutritional side effects, differences in the durations of these side effects, and differences in weight loss between patients undergoing single and combination immunotherapies. METHODS: In this historical cohort study, which was performed from 2017 to 2019, a total of 50 patients who received one type and 50 patients who received two types of immunotherapy were randomly selected, resulting in a sample of 100 patients. The primary objectives were to assess (a) the incidence of nutritional side effects, (b) the differences in the durations of these side effects, and (c) the differences in weight loss between the two groups. The secondary objectives were to assess the time to the first side effect, the time to the first unplanned hospital admission, unplanned hospital admissions, consultations from a dietitian, and nutritional interventions. Data were collected from the electronic patient record. Differences between groups were explored using the two-sample t-test, Mann-Whitney U test, Fisher exact test, or Wilcoxon rank sum test, depending on the type of data and the test assumptions. The time to the first side effect and the time to the first unplanned hospital admission are presented as Kaplan-Meier curves, and differences were calculated using a Cox proportional hazards model. RESULTS: Patients undergoing a combination of two types of immunotherapy were found to have side effects for statistically significantly longer durations than patients receiving one type of immunotherapy (20 days versus 10 days, p = 0.045). Moreover, patients undergoing a combination of two types of immunotherapy were found to lose more weight (6.2 kg versus 1.2 kg, p < 0.001). At least one side effect was reported in 86% of the patients in the one-therapy group and in 90% of the patients in the combination-therapy group. Furthermore, a high incidence of decreased appetite (70% and 86%), nausea (52% and 68%), vomiting (22% and 46%), and diarrhea/colitis (56% and 54%) was found in both groups. However, the time to the first side effect and the time to the first hospital admission were not statistically significantly different between the one-therapy and combination-therapy groups. Of the total cohort, 26% were admitted unexpectedly during the immunotherapy because they developed immunotherapy-related side effects, whereas 38% of the patients in our sample consulted a dietitian. CONCLUSIONS: Nutritional side effects are common in patients treated with immunotherapy. Generally, treatment with a combination of two types of immunotherapy is associated with an increased incidence of nutritional side effects. These side effects last longer and patients lose more weight compared to those receiving one type of immunotherapy.

Is quantitative ultrasound a measure for metabolic bone disease in preterm-born infants? A prospective subcohort study.

In this study, we aimed to (a) evaluate postnatal changes in bone development in relation to growth and (b) to determine factors associated with bone development, from birth to 24 months of corrected age. The metacarpal speed of sound (mcSOS) and metacarpal bone transmission time (mcBTT) were used to evaluate bone development in 98 preterm infants, during hospitalization and follow-up. The mcSOS and mcBTT values not only declined in the first 6 weeks of hospitalization but also during follow-up. The mcSOS reached its lowest point at 12 months (ß=-34.64), while the mcBTT reached a plateau between 12 and 24 months (ß=0.06). Univariable analysis showed that gender (p=0.28), time (p<0.001), and growth parameters (p<0.001) were significant negative associated factors with mcSOS, whereas with mcBTT, time (p=0.009), length (p=0.063), length standard deviation scores (SDS) (p=0.027), head circumference (p=0.005), and head circumference SDS (p=0.007) were significant positive. The multivariable model revealed that time (ß= -3.364, p=<0.001), weight (ß=-0.007, p<0.001) and length (ß=1.163, p<0.001) for mcSOS and length (ß=-0.021, p<0.001), and length SDS (ß= 0.066, p<0.001) and head circumference (ß=0.049, p<0.001) for mcBTT remained highly significant associated factors.Conclusion: The most important finding is that mcSOS decreased and the mcBTT reached a plateau to 24 months. In both mcSOS and mcBTT, the growth parameters were significant factors.Clinical Trial Registration: N/A What is known: • Metabolic bone disease is one of the possible long term adverse outcomes after preterm birth. • Metacarpal speed of sound (mcSOS) and metacarpal bone transmission time (mcBTT) decline in the early postnatal period. What is new: • During follow-up, mcSOS further decreased and reached its lowest point at 12 months, while the mcBTT reached a plateau up to 24 months. • Postnatal nutrition in relation to comorbidity does not meet the optimal mineralization rate of the developing preterm bone.

Strict isolation requires a different approach to the family of hospitalised patients with COVID-19: A rapid qualitative study.

BACKGROUND: The outbreak of the COVID-19 pandemic influenced family-centred care dramatically due to restricting visiting policies. In this new situation, nurses were challenged to develop new approaches to involve family members in patient care. A better understanding of these changes and the experiences of nurses is essential to make an adaptation of procedures, and to secure a family-centred approach in care as much as possible. OBJECTIVES: The aim of this study was to investigate how family involvement had taken place, and to explore the experiences of nurses with family involvement during the COVID-19 outbreak. In addition, we aimed to formulate recommendations for the involvement of family. METHODS: We conducted a qualitative study using patient record review and focus-group interviews between April and July 2020. We reviewed records of patients with confirmed COVID-19, who were admitted to the COVID-19 wards at two affiliated university hospitals in the Netherlands. All records were searched for notations referring to family involvement. In two focus-groups, nurses who worked at the COVID-19 wards were invited to share their experiences. The Rigorous and Accelerated Data Reduction (RADaR) method was used to collect, reduce and analyse the data. RESULTS: In total, 189 patient records were reviewed and nine nurses participated in the focus-group meetings. Patient records revealed infrequent and often unstructured communication with focus on physical condition. Nurses confirmed that communication with family was far less than before and that the physical condition of the patient was predominant. The involvement of family in care was limited to practicalities, although more involvement was described in end-of-life situations. Nurses experienced moral distress due to the visiting restrictions, though some acknowledged that they had experienced the direct patient care so intense and burdensome, that family contact simply felt too much. CONCLUSION: The communication with and involvement of family in hospital care changed enormously during the COVID-19 outbreak. Based on the identified themes, we formulated recommendations that may be helpful for family-centered care in hospitals during periods of restricted visiting policy.

Prevalence and risk factors of inappropriate use of intravenous and urinary catheters in surgical and medical patients.

BACKGROUND: Previously, the RICAT (Reduction of Inappropriate use of intravenous and urinary CATheters) study had been conducted by ourselves to reduce inappropriate use of intravenous and urinary catheters in medical wards to prevent healthcare-associated infections. AIM: To compare surgical and medical wards, and to determine risk factors for inappropriate catheter use. METHODS: A cross-sectional study was performed from October, 2017, to May, 2018, in surgical wards of two university hospitals in the Netherlands. Patients were prospectively observed every other week for seven months. Inappropriate use was compared with non-surgical wards in the RICAT study. FINDINGS: In all, 409 surgical patients were included, and they were compared with 1781 medical patients. Inappropriate use occurred in 36 (8.5%) out of 425 peripheral intravenous catheters in 373 surgical patients, compared to 400 (22.9%) out of 1747 peripheral intravenous catheters in 1665 medical patients, a difference of 14.4% (95% confidence interval (CI): 11.1-17.8; P < 0.001). Inappropriate use of urinary catheters occurred in 14 (10.4%) out of 134 surgical patients, compared to 105 (32.4%) out of 324 medical patients, a difference of 22.0% (95% CI: 14.7-29.2; P < 0.001). Subgroup analysis in the two university hospitals confirmed these differences. The main risk factor for inappropriate use of peripheral intravenous catheters was admission in medical wards (odds ratio (OR): 3.50; 95% CI: 2.15-5.69), which was also one of the main risk factors for urinary catheters (OR: 2.75; 95% CI: 1.36-5.55). CONCLUSION: Inappropriate use of catheters is more common in medical wards compared to surgical wards. Prevention strategies to reduce healthcare-associated infections should primarily focus on sites with high prevalence of inappropriate use.

Effects of medicinal food plants on impaired glucose tolerance: A systematic review of randomized controlled trials.

BACKGROUND: The objective of this systematic review was to assess available scientific data on the efficacy and safety of medicinal food plants for the treatment of impaired glucose tolerance. METHODS: We included randomized controlled trials (RCTs) with a minimum follow-up period of 6weeks. The diagnosis was determined by fasting plasma glucose values after two-hour oral glucose tolerance testing (OGTT). Two authors independently extracted data and evaluated bias. The Cochrane tool of risk of Bias Tool was used. RESULTS: This review included ten trials. Most studies were highly biased as data were incomplete or reporting was selective. The two-hour fasting plasma glucose after the curcumin extract intervention showed statistical significance after 3, 6 and 9months: p<0.01. Also, glycosylated haemoglobin levels A1c (HbA1c) values after curcumin extract intervention showed statistical significance after 3, 6 and 9months: p<0.01. Insulin resistance (HOMA-IR) after curcumin extract intervention showed statistical significance after 6months and after 9months: p<0.05 and p<0.01. CONCLUSIONS: Curcumin has shown the confident results to be effective for the treatment of impaired glucose tolerance. Fenugreek and flaxseed may also be effective, but due to low quality of these studies the results must be interpreted with caution.

Clinimetric properties of the Nociception Coma Scale (-Revised): A systematic review.

The Nociception Coma Scale is a nociception behaviour observation tool, developed specifically for patients with disorders of consciousness (DOC) due to (acquired) brain injury. Over the years, the clinimetric properties of the NCS and its revised version (NCS-R) have been assessed, but no formal summary of these properties has been made. Therefore, we performed a systematic review on the clinimetric properties (i.e. reliability, validity, responsiveness and interpretability) of the NCS(-R). We systematically searched CENTRAL, CINAHL, Embase, PsycInfo and Web of Science until August 2015. Two reviewers independently selected the clinimetric studies and extracted data with a structured form. Included studies were appraised on quality with the COSMIN checklist. Eight studies were found eligible and were appraised with the COSMIN checklist. Although nearly all studies lacked sample size calculation, and were executed by the same group of authors, the methodological quality ranged from fair to excellent. Important aspects of reliability, construct validity and responsiveness have been studied in depth and with sufficient methodological quality. The overview of clinimetric properties in this study shows that the NCS and NCS-R are both valid and useful instruments to assess nociceptive behaviour in DOC patients. The studies provide guidance for the choice in NCS-R cut-off value for possible pain treatment and cautions awareness of interprofessional differences in NCS-R measurements. SIGNIFICANCE: This systematic review provides a structured overview of the clinimetric properties of the Nociception Coma Scale (-Revised) and provides insights for a solid evidence-based nociception behaviour assessment and treatment plan.

The clinimetric properties of the COMFORT scale: A systematic review.

The COMFORT scale is a measurement tool to assess distress, sedation and pain in nonverbal paediatric patients. Several studies have described the COMFORT scale, but no formal assessment of the methodological quality has been undertaken. Therefore, we performed a systematic review to study the clinimetric properties of the (modified) COMFORT scale in children up to 18 years. We searched Central, CINAHL, Embase, Medline, PsycInfo and Web of Science until December 2014. The selection, data extraction and quality assessment were performed independently by two reviewers. Quality of the included studies was appraised using the COSMIN checklist. We found 30 studies that met the inclusion criteria. Most participants were ventilated children up to 4 years without neurological disorders. The results on internal consistency and interrater reliability showed values of >0.70 in most studies, indicating an adequate reliability. Construct validity resulted in correlations between 0.68 and 0.84 for distress, between 0.42 and 0.94 for sedation and between 0.31 and 0.96 for pain. The responsiveness of the (modified) COMFORT scale seems to be adequate. The quality of the included studies ranged from poor to excellent. The COMFORT scale shows overall an adequate reliability in providing information on distress, sedation and pain. Construct validity varies from good to excellent for distress, from moderate to excellent for sedation, and from poor to excellent for pain. The included studies were clinically and methodologically heterogeneous, hampering firm conclusions. WHAT DOES THIS REVIEW ADD?: An in-depth assessment of the clinimetric properties of the COMFORT scale. The COMFORT scale shows overall an adequate reliability in providing information on distress, sedation and pain. Construct validity varies from good to excellent for distress, from moderate to excellent for sedation, and from poor to excellent for pain.

Evaluation of a rapid molecular algorithm for detection of pandemic influenza A (H1N1) 2009 virus and screening for a key oseltamivir resistance (H275Y) substitution in neuraminidase.

BACKGROUND: Rapid and specific molecular tests for identification of the recently identified pandemic influenza A/H1N1 2009 virus as well as rapid molecular tests to identify antiviral resistant strains are urgently needed. OBJECTIVES: We have evaluated the performance of two novel reverse transcriptase polymerase chain reactions (RT-PCRs) targeting specifically hemagglutinin and neuraminidase of pandemic influenza A/H1N1 virus in combination with a conserved matrix PCR. In addition, we investigated the performance of a novel discrimination RT-PCR for detection of the H275Y resistance mutation in the neuraminidase gene. STUDY DESIGN: Clinical performance of both subtype specific RT-PCR assays was evaluated through analysis of 684 throat swaps collected from individuals meeting the WHO case definition for the novel pandemic influenza virus. Analytical performance was analyzed through testing of 10-fold serial dilutions of RNA derived from the first Dutch sequenced and cultured confirmed case of novel pandemic influenza infection. Specificity and discriminative capacities of the H275Y discrimination assay were performed by testing wild type and recombinant H275Y pandemic influenza. RESULTS: 121 throat swaps collected from April 2009 to July 2009 were positive by at least two out of three RT-PCRs, and negative for the seasonal H3/H1 subtype specific RT-PCR assays. 117 of these were tested positive for all three (Ct-values from 15.1 to 36.8). No oseltamivir resistance was detected. CONCLUSIONS: We present a sensitive and specific approach for detection of pandemic influenza A/H1N1 2009 and a rapid RT-PCR assay detecting a primary oseltamivir resistance mutation which can be incorporated easily into clinical virology algorithms.

The effectiveness of chlorhexidine-silver sulfadiazine impregnated central venous catheters in patients receiving high-dose chemotherapy followed by peripheral stem cell transplantation.

Immuno-compromised patients are at high risk for all kind of infections. Unfortunately, they need central venous catheters (CVCs), which are associated with infectious complications. In this study we examined the effectiveness of chlorhexidine-silver sulfadiazine impregnated CVCs to prevent catheter-related infections in patients receiving high-dose chemotherapy followed by peripheral stem cell transplantation. This historical cohort study evaluated 139 patients of whom 70 patients were provided with non-impregnated CVCs and 69 patients with impregnated CVCs. Patients were treated for different diagnoses. The median number of days a CVC stayed in situ was 18 in the non-impregnated group and 16 in the impregnated group. The median duration of neutropenia of patients with non-impregnated CVCs was 9 days compared with 7 days of patients with impregnated CVCs. We found less catheter colonization (CC) in patients with chlorhexidine-silver sulfadiazine CVCs (RR 0.63, 95% CI 0.41-0.96; P = 0.03). Catheter-related blood stream infections (CR-BSI) were also diminished, but this result was not statistically significant (RR 0.15, 95% CI 0.02-1.15; P = 0.06). The reduction in CC and CR-BSI did not diminish the incidence of fever. We conclude that the use of chlorhexidine-silver sulfadiazine impregnated CVCs provide an important improvement in the attempt to reduce CC and CR-BSI.

The mannose cap of mycobacterial lipoarabinomannan does not dominate the Mycobacterium-host interaction.

Pathogenic mycobacteria have the ability to persist in phagocytic cells and to suppress the immune system. The glycolipid lipoarabinomannan (LAM), in particular its mannose cap, has been shown to inhibit phagolysosome fusion and to induce immunosuppressive IL-10 production via interaction with the mannose receptor or DC-SIGN. Hence, the current paradigm is that the mannose cap of LAM is a crucial factor in mycobacterial virulence. However, the above studies were performed with purified LAM, never with live bacteria. Here we evaluate the biological properties of capless mutants of Mycobacterium marinum and M. bovis BCG, made by inactivating homologues of Rv1635c. We show that its gene product is an undecaprenyl phosphomannose-dependent mannosyltransferase. Compared with parent strain, capless M. marinum induced slightly less uptake by and slightly more phagolysosome fusion in infected macrophages but this did not lead to decreased survival of the bacteria in vitro, nor in vivo in zebra fish. Loss of caps in M. bovis BCG resulted in a sometimes decreased binding to human dendritic cells or DC-SIGN-transfected Raji cells, but no differences in IL-10 induction were observed. In mice, capless M. bovis BCG did not survive less well in lung, spleen or liver and induced a similar cytokine profile. Our data contradict the current paradigm and demonstrate that mannose-capped LAM does not dominate the Mycobacterium-host interaction.

Heterogeneity among infecting strains of Pseudomonas aeruginosa in diverse departments of a large Tunisian hospital.

Clinical isolates of Pseudomonas aeruginosa were obtained during a half-year screening period of five different wards of the La Rabta Hospital (Tunis). Distinct clinical isolates (N= 82) were obtained from patients, 40 (48%) of which originated from the Department of Otolaryngology. In order to define the local epidemiology of this opportunistic organism, all strains were serotyped, analysed for pyocin production and genetically characterized with the help of pulsed-field gel electrophoresis (PFGE). The data show that, despite the frequent occurrence of identical serotypes, most of the isolates represent unique pyocin types (N= 53) and genotypes (N= 64). A combination of the pyocin and PFGE data showed that nearly all strains were of unique types, except for two pairs of strains. A limited number of strain clusters was observed on the basis of DNA typing data alone. This involved eight genotypes, some of which were clustered with respect to clinical environment or time. Genotype 22 occurred most frequently (6/83, 7%) and independently of time and locale, indicating that it may represent either a clonal type constituting a major fraction of all P. aeruginosa isolates in the region or a more prevalent organism. Despite a relatively high incidence of P. aeruginosa infections, the polyclonality of these strains shows that, in La Rabta Hospital, pseudomonal infections are not primarily due to excessive spread of a single bacterial genotype.

Phase variation in H type I and Lewis a epitopes of Helicobacter pylori lipopolysaccharide.

Helicobacter pylori NCTC 11637 lipopolysaccharide (LPS) expresses the human blood group antigens Lewis x (Le(x)), Le(y), and H type I. In this report, we demonstrate that the H type I epitope displays high-frequency phase variation. One variant expressed Le(x) and Le(y) and no H type I as determined by serology; this switch was reversible. Insertional mutagenesis in NCTC 11637 of JHP563 (a poly(C) tract containing an open reading frame homologous to glycosyltransferases) yielded a transformant with a serotype similar to the phase variant. Structural analysis of the NCTC 11637 LPS confirmed the loss of the H type I epitope. Sequencing of JHP563 in strains NCTC 11637, an H type I-negative variant, and an H type I-positive switchback variant showed a C14 (gene on), C13 (gene off), and C14 tract, respectively. Inactivation of strain G27, which expresses Le(x), Le(y), H type I, and Le(a), yielded a transformant that expressed Le(x) and Le(y). We conclude that JHP563 encodes a beta3-galactosyltransferase involved in the biosynthesis of H type I and Le(a) and that phase variation in H type I is due to C-tract changes in this gene. A second H type I-negative variant (variant 3a) expressed Le(x) and Le(a) and had lost both H type I and Le(y) expression. Inactivation of HP093-HP094 resulted in a transformant expressing Le(x) and lacking Le(y) and H type I. Structural analysis of a mutant LPS confirmed the serological data. We conclude that the HP093-HP094 alpha2-fucosyltransferase (alpha2-FucT) gene product is involved in the biosynthesis of both Le(y) and Le(x). Finally, we inactivated HP0379 in strain 3a. The transformant had lost both Le(x) and Le(a) expression, which demonstrates that the HP0379 gene product is both an alpha3- and an alpha4-FucT. Our data provide understanding at the molecular level of how H. pylori is able to diversify in the host, a requirement likely essential for successful colonization and transmission.

Phase variation in Helicobacter pylori lipopolysaccharide due to changes in the lengths of poly(C) tracts in alpha3-fucosyltransferase genes.

The lipopolysaccharide (LPS) of Helicobacter pylori expresses the Lewis x (Lex) and/or Ley antigen. We have shown previously that H. pylori LPS displays phase variation whereby an Lex-positive strain yields variants with different LPS serotypes, for example, Lex plus Ley or nonfucosylated polylactosamine. H. pylori has two alpha3-fucosyltransferase genes that both contain poly(C) tracts. We now demonstrate that these tracts can shorten or lengthen randomly, which results in reversible frameshifting and inactivation of the gene products. We provide genetic and serological evidence that this mechanism causes H. pylori LPS phase variation and demonstrate that the on or off status of alpha3-fucosyltransferase genes determines the LPS serotypes of phase variants and clinical isolates. The role of the alpha3-fucosyltransferase gene products in determining the LPS serotype was confirmed by structural-chemical analysis of alpha3-fucosyltransferase knockout mutants. The data also show that the two alpha3-fucosyltransferase genes code for enzymes with different fine specificities, and we propose the names futA and futB to designate the orthologs of the H. pylori 26695 alpha3-fucosyltransferase genes HP0379 and HP0651, respectively. The data also show that the alpha3-fucosylation precedes alpha2-fucosylation [corrected], an order of events opposite to that which prevails in mammals. Finally, the data provide an understanding at the molecular level of the mechanisms underlying LPS diversity in H. pylori, which may play an important role in adaptation to the host.

Anti-lipid A monoclonal antibody centoxin (HA-1A) binds to a wide variety of hydrophobic ligands.

This note describes the binding specificities of four lipid A monoclonal antibodies (MAbs) including Centoxin (HA-1A); these MAbs display similar binding properties. MAbs reacted with lipid A and heat-killed smooth bacteria, whereas no reactivity was observed with smooth lipopolysaccharide (LPS). Immunoblotting of bacterial extracts separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the MAbs bound to many polypeptide bands including the molecular weight markers. Denaturation of bovine serum albumin (BSA) by boiling or dithiothreitol treatment unmasked antibody epitopes. In addition, binding both to a hydrophobic aliphatic C12 chain covalently coupled to BSA and to single-stranded DNA was observed. The polyreactivity of these clones is most likely mediated by a preferential reactivity with hydrophobic molecular patches.

Phase variation in Helicobacter pylori lipopolysaccharide.

Helicobacter pylori NCTC 11637 lipopolysaccharide (LPS) expresses the human blood group antigen Lewis x (Le(x)) in a polymeric form. Le(x) is beta-D-galactose-(1-4)-[alpha-L-fucose-(1-3)]-beta-D-acetylglucosamine. Schematically the LPS structure is (Le(x))n-core-lipid A. In this report, we show that Le(x) expression is not a stable trait but that LPS displays a high frequency (0.2 to 0.5%) of phase variation, resulting in the presence of several LPS variants in one bacterial cell population. One type of phase variation implied the loss of alpha1,3-linked fucose, resulting in variants that expressed nonsubstituted polylactosamines (also called the i antigen), i.e., Le(x) minus fucose; LPS: (lactosamine)n-core-lipid A. The switch of Le(x) to i antigen was reversible. A second group of variants arose by loss of polymeric main chain which resulted in expression of monomeric Le(y); LPS: (Le(y))-core-lipid A. A third group of variants arose by acquisition of alpha1,2-linked fucose which hence expressed Le(x) plus Le(y); LPS: (Le(y))(Le(x))n-core-lipid A. The second and third group of variants switched back to the parental phenotype [(Le(x))-core-lipid A] in lower frequencies. Part of the variation can be ascribed to altered expression levels of glycosyltransferase levels as assessed by assaying the activities of galactosyl-, fucosyl-, and N-acetylglucosaminyltransferases. Clearly phase variation increases the heterogeneity of H. pylori, and this process may be involved in generating the very closely related yet genetically slightly different strains that have been isolated from one patient.

Potential role of molecular mimicry between Helicobacter pylori lipopolysaccharide and host Lewis blood group antigens in autoimmunity.

Helicobacter pylori is involved in gastritis, gastric and duodenal ulcers, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. Earlier studies already suggested a role for autoimmune phenomena in H. pylori-linked disease. We now report that lipopolysaccharides (LPS) of H. pylori express Lewis y, Lewis x, and H type I blood group structures similar to those commonly occurring in gastric mucosa. Immunization of mice and rabbits with H. pylori cells or purified LPS induced an anti-Lewis x or y or anti-H type I response, yielding antibodies that bound human and murine gastric glandular tissue, granulocytes, adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma cells. Experimental oral infections in mice or natural infection in humans yielded anti-Lewis antibodies also. The beta chain of gastric (H+,K+)-ATPase, the parietal cell proton pump involved in acid secretion, contained Lewis y epitopes; gastric mucin contained Lewis x and y antigenic determinants. Growth in mice of a hybridoma that secretes H. pylori-induced anti-Lewis y monoclonal antibodies resulted in histopathological evidence of gastritis, which indicates a direct pathogenic role for anti-Lewis antibodies. In conclusion, our observations demonstrate that molecular mimicry between H. pylori LPS and the host, based on Lewis antigens, and provide understanding of an autoimmune mechanism for H. pylori-associated type B gastritis.

Isolation and characterization of chromosomal mTn 10 insertion mutations affecting K88 fimbriae production in Escherichia coli.

mTn 10 transposon mutagenesis of Escherichia coli producing K88 fimbria was carried out in order to identify host factors involved in the regulation of the fae (K88) operon and the production of K88 fimbriae. Five independent chromosomal insertion mutants were obtained which showed an increased expression of K88 fimbriae. Inverse PCR and nucleotide sequencing were carried out to characterize the mutations. One insertion affected the Ipp gene, encoding the major outer membrane lipoprotein. Another mutation was found to be located in the Irp gene, encoding the 'global' regulatory protein Lrp (leucine responsive regulatory protein). A third mutant was found to affect the expression of rfaF, encoding heptosyltransferase II, which resulted in a partially wild-type and partially Re-Rd1 type of LPS. A fourth mutation affected sseB, a gene involved in serine-sensitivity of E. coli cells. Another mutant contained an insertion in an unknown region of the E. coli genome. The mutants were further characterized with respect to K88 as well as K99 fimbriae production.

Diversity in lipid A binding ligands: comparison of lipid A monoclonal antibodies with rBPI23.

1. Mabs with a high affinity for free lipid A do not bind when it is covalently linked, i.e. in the form of LPS. 2. Lipid A-binding Mabs may be divided into three categories: I. Monoreactive Mabs that bind to the hydrophillic backbone of lipid A II. Polyreactive Kdo Mabs III. Polyreactive Mabs that bind by hydrophobic interactions 3. rBPI23 binds either free or covalently linked lipid A.

Antigenic and immunogenic differences in lipopolysaccharides of Escherichia coli J5 vaccine strains of different origins.

Escherichia coli strain J5 mutants of various origins have often been used as vaccines for induction of cross-reactive, cross-protective antibodies directed against the lipopolysaccharide (LPS) core region. The antigenic composition of LPS from J5 strains of different origin, i.e. strains J5(U), J5(UK), J5(2877) and J5(a), was investigated using monoclonal antibodies (mAbs) reactive only with LPS of a given chemotype, i.e. one specific for the incomplete E. coli core of the Rc chemotype, a second mAb reactive only with the E. coli R3 complete core, and a third specific for the O-antigen of E. coli serovar O111. The LPS of strains J5(U) and J5(a) is almost exclusively composed of LPS of the Rc chemotype, LPS of the J5(UK) strain is composed of Rc LPS and R3 complete core, while LPS of the J5(2877) strain contains Rc, R3 complete core and O-antigen. Growth of the bacteria in medium supplemented with galactose led to increased expression of complete core. The immune responses to the various strains were investigated. Antiserum to the J5 strain expressing the largest amount of R3 core [J5(UK)] had much higher anti-R3 LPS antibody titres compared to antiserum to the other strains. mAb 53, representative of the anti-R3 response to J5 strains containing complete core, bound to those E. coli LPS expressing the R3 core. Thus, the R3 LPS, present in some J5 vaccine strains is at least partially responsible for some of the cross-reactivities exhibited by some anti-J5 antisera.(ABSTRACT TRUNCATED AT 250 WORDS)