Clinical determinants of intestinal failure and death in preterm infants with surgical necrotizing enterocolitis

OBJECTIVE

We sought to investigate the clinical determinants of intestinal failure and death in preterm infants with surgical NEC.

METHODS

Retrospective comparison of clinical information between Group A = intestinal failure (Parenteral nutrition (PN) >90 days) and death and Group B = survivors and with PN dependence < 90 days in preterm infants with surgical NEC.

RESULTS

Group A (n = 99/143) had a lower mean gestational age (26.4 weeks [SD3.5] vs. 29.4 [SD 3.5]; p = 0.013), lower birth weight (873 gm [SD 427g] vs. 1425 gm [894g]; p = <0.001), later age of NEC onset (22 days [SD20] vs. 16 days [SD 17]; p = 0.128), received surgery later (276 hours [SD 544] vs. 117 hours [SD 267]; p = 0.032), had cholestasis, received dopamine (80.6% vs. 58.5%; p = 0.010) more frequently and had longer postoperative ileus time (19.8 days [SD 15.4] vs. 11.8 days [SD 6.5]; p = <0.001) and reached full feeds later (93 days [SD 45] vs. 44 [SD 22]; p = <0.001) than Group B.On multivariate logistic regression, higher birth weight was associated with lower risk (OR 0.35, 95% CI 0.15-0.82; p = 0.016) of TPN > 90 days or death. Longer length of bowel resected (OR 1.76, 95% CI 1.02-3.02; p = 0.039) and longer postoperative ileus (OR 2.87, 95% CI 1.26-6.53; p = 0.011) were also independently associated with TPN >90days or death adjusted for gestational age and antenatal steroid treatment.

CONCLUSION

In preterm infants with surgical NEC, clinical factors such as lower birth weight, longer bowel loss, and postoperative ileus days were significantly and independently associated with TPN >90 days or death.

Differential Expression of CB1 Cannabinoid Receptor and Cannabinoid Receptor Interacting Protein 1a in Labor

Background: The endocannabinoid system is present in multiple organ systems and is involved in smooth muscle regulation, immune function, neuroendocrine modulation, and metabolism of tissues. Limited data are available regarding the presence and role of this system in reproductive tissues. Components of the endocannabinoid system have been identified in myometrial and placental tissues. However, no study has investigated differential expression of the endocannabinoid system in labor. Objectives: The purpose of this study was to identify and quantify two components of the endocannabinoid system, the CB1 cannabinoid receptor and cannabinoid receptor interacting protein 1a (CRIP1a) in uterine and placental tissues, and to determine if there is differential expression in tissues exposed to labor. We hypothesized that CB1 cannabinoid receptor concentration would be altered in uterine and placental tissue exposed to labor compared with tissues not exposed to labor. Study Design: Uterine and placental tissue samples were collected in nine laboring and 11 nonlaboring women undergoing cesarean delivery. CB1 cannabinoid receptor and CRIP1a presence and quantification were evaluated using western blot, immunohistochemistry, and real-time quantitative polymerase chain reaction. Statistical comparisons of laboring and nonlaboring subjects were made for uterine and placental tissue using a Mann-Whitney test. Results: Immunohistochemistry demonstrated positive staining for CB1 cannabinoid receptors and CRIP1a in uterine tissue. The protein abundance of CB1 cannabinoid receptor in uterine tissue was significantly lower in tissues exposed to labor (p=0.01). The protein abundance of CRIP1a was lower in uterine tissue exposed to labor but did not reach statistical significance (p=0.06). mRNA expression of CB1 cannabinoid receptor (p=0.20) and CRIP1a (p=0.63) did not differ in labored compared with nonlabored uterine tissues. Conclusions: Our findings of diminished protein density of CB1 cannabinoid receptor in uterine tissue exposed to labor support the hypothesis that the endocannabinoid system plays a role in parturition. Our data add to the growing body of evidence indicating the endocannabinoid system is of importance for successful reproduction and support the need for additional research investigating this complex system as it pertains to labor. ClinicalTrials.gov ID: NCT03752021.

Airy light-sheet Raman imaging

Light-sheet fluorescence microscopy has greatly improved the speed and overall photostability of optically sectioning cellular and multi-cellular specimens. Similar gains have also been conferred by light-sheet Raman imaging; these schemes, however, rely on diffraction limited Gaussian beams that hinder the uniformity and size of the imaging field-of-view, and, as such, the resulting throughput rates. Here, we demonstrate that a digitally scanned Airy beam increases the Raman imaging throughput rates by more than an order of magnitude than conventional diffraction-limited beams. Overall, this, spectrometer-less, approach enabled 3D imaging of microparticles with high contrast and 1 µm axial resolution at 300 msec integration times per plane and orders of magnitude lower irradiation density than coherent Raman imaging schemes. We detail the apparatus and its performance, as well as its compatibility with fluorescence light-sheet and quantitative-phase imaging towards rapid and low phototoxicity multimodal imaging.

Fatal systemic (paradoxical) air embolism diagnosed by postmortem funduscopy

Air embolism is often unrecognized and underreported. Published case reports or case series describe only rare fundal examinations of retinal air emboli (RAE)-a distinctive sign of systemic air embolism. We report an infant, found unresponsive at home, who died in the emergency department after unsuccessful resuscitative efforts. Before the autopsy, diagnostic RAE were recognized and imaged during postmortem funduscopy. Postmortem radiography and an autopsy confirmed systemic (paradoxical) air embolism due to inflicted abdominal and thoracic blunt force injuries. While a few descriptions and illustrations of RAE occur in case reports, we found no published photographic images of RAE in infants, children, or adults. This case report describes and photographically documents classic RAE associated with fatal systemic (paradoxical) air embolism. Complementing postmortem radiography and judicious autopsy techniques, the detection of RAE can aid pathologists in diagnosing systemic air embolism.

Molecular and clinicopathologic characterization of intravenous leiomyomatosis

Intravenous leiomyomatosis (IVL) is an unusual uterine smooth muscle proliferation that can be associated with aggressive clinical behavior despite a histologically benign appearance. It has some overlapping molecular characteristics with both uterine leiomyoma and leiomyosarcoma based on limited genetic data. In this study, we assessed the clinical and morphological characteristics of 28 IVL and their correlation with molecular features and protein expression, using array comparative genomic hybridization (aCGH) and Cyclin D1, p16, phosphorylated-Rb, SMARCB1, SOX10, CAIX, SDHB and FH immunohistochemistry. The most common morphologies were cellular (n = 15), usual (n = 11), and vascular (n = 5; including 3 cellular IVL showing both vascular and cellular features). Among the immunohistochemical findings, the most striking was that all IVL showed differential expression of either p16 or Cyclin D1 in comparison to surrounding nonneoplastic tissue. Cytoplasmic phosphorylated-Rb was present in all but one IVL with hyalinization. SMARCB1, FH, and SDHB were retained; S0X10 and CAIX were not expressed. The most common genetic alterations involved 1p (39%), 22q (36%), 2q (29%), 1q (25%), 13q (21%), and 14q (21%). Hierarchical clustering analysis of recurrent aberrations revealed three molecular groups: Groups 1 (29%) and 2 (18%) with associated del(22q), and Group 3 (18%) with del(10q). The remaining IVL had nonspecific or no alterations by aCGH. Genomic index scores were calculated for all cases and showed no significant difference between the 14 IVL associated with aggressive clinical behavior (extrauterine extension or recurrence) and those without (median scores 5.15 vs 3.5). Among the 5 IVL associated with recurrence, 4 had a vascular morphology and 3 had alterations of 8q. Recurrent chromosome alterations detected herein overlap with those observed in the spectrum of uterine smooth muscle tumors and involve genes implicated in mesenchymal tumors at different sites with distinct morphological features.

Absence of rickets in infants with fatal abusive head trauma and classic metaphyseal lesions

PURPOSE

To determine if rickets is present in cases of infant homicide with classic metaphyseal lesions (CMLs) and other skeletal injuries.

MATERIALS AND METHODS

This study was exempt from the institutional human subjects board review because all infants were deceased. An archival review (1984-2012) was performed of the radiologic and histopathologic findings of 46 consecutive infant fatalities referred from the state medical examiner's office for the evaluation of possible child abuse. Thirty infants with distal femoral histologic material were identified. Additional inclusion criteria were as follows: (a) The medical examiner determined that the infant had sustained a head injury and that the manner of death was a homicide, (b) at least one CML was evident at skeletal survey, (c) CMLs were confirmed at autopsy, and (d) non-CML fractures were also present. Nine infants (mean age, 3.9 months; age range, 1-9 months) were identified. Two pediatric radiologists independently reviewed the skeletal surveys for rachitic changes at the wrists and knees. A bone and soft tissue pathologist reviewed the distal femoral histologic slices for rickets.

RESULTS

There were no radiographic or pathologic features of rickets in the cohort.

CONCLUSION

The findings provide no support for the view that the CML is due to rickets. Rather, they strengthen a robust literature that states that the CML is a traumatic injury commonly encountered in physically abused infants.

Devolatilisation kinetics and pyrolytic analyses of Tectona grandis (teak)

Devolatilisation kinetics and pyrolytic analyses were carried out on Tectona grandis (teak) using iso-conversional methods (Flynn-Wall-Ozawa and Starink) and analytical Py-GC/MS technique respectively. Proximate and elemental analyses were also performed and they showed that the ash and C contents and the HHV were 0.7%, 49.6% and 19.8MJ/kg respectively. Biomass sample was subjected to multiple heating rates (5-35K/min) in thermogravimetric experiments and kinetic parameters were evaluated from the non-isothermal TGA curves. The activation energy (E) varied between 222 and 300kJ/mol as a function of degree of conversion. Similarly, the pre-exponential frequency factor (A) varied between 9.6×10(17) and 9.55×10(24)min(-1). Analytical Py-GC/MS showed the presence of CO2, acetic acid, furan+2-butanone, levoglucosan, trans-coniferyl alcohol and lignin derivatives. The proportion of phenolic compounds identified was more than one-third with isoeugenol, acetoguaiacone, and 4-vinylguaiacol showing dominance.

Discordant radiologic and histological dimensions of the zone of provisional calcification in fetal piglets

BACKGROUND

Studies have shown that the fracture plane of the classic metaphyseal lesion (CML) of infant abuse occurs in the region of the primary spongiosa, encompassing a radiodense fracture fragment customarily referred to as the "zone of provisional calcification" or ZPC. However, the zone of provisional calcification is defined differently in the pathology and the imaging literature, potentially impeding efforts to understand the fundamental morphological features of the classic metaphyseal lesion.

OBJECTIVE

We systematically correlated micro-CT data with histology in piglets to explore the differing definitions of the zone of provisional calcification and to elucidate the anatomical basis for divergent definitions.

MATERIALS AND METHODS

The distal tibias of five normal fetal piglets were studied postmortem. The specimens were resected and imaged with digital radiography (50 μm resolution) and micro-CT (45 μm(3) isotropic resolution). Image processing techniques were applied to the micro-CT data for visualization and data analysis. The resected tissue specimens were then processed routinely and the light microscopic features were correlated with the imaging findings.

RESULTS

The longitudinal dimension of the radiologic zone of provisional calcification is greater than the histological ZPC, and these dimensions are statistically distinct (P < 0.0002). The radiologic zone of provisional calcification consists of two adjoining mineralized discoid regions that span the chondro-osseous junction-a thick discoid region that encompasses the densest region of the primary spongiosa, and a thin discoid region (corresponding to the histological ZPC) that is situated in the base of the physis adjacent to the metaphysis.

CONCLUSION

The correlation of the normal histology and micro-CT appearance of this dynamic and complex region provides an anatomical foundation upon which a deeper appreciation of the morphology of the classic metaphyseal lesion can be built.

Nephrogenic systemic fibrosis: a pathologic study of autopsy cases

CONTEXT

-Nephrogenic systemic fibrosis (NSF) is a rare but serious disorder initially described as a purely dermatologic process. Isolated autopsy reports have described multiorgan involvement by this disease.

OBJECTIVE

-To further illustrate the varied and systemic involvement of NSF by describing the autopsy experience at the Massachusetts General Hospital.

DESIGN

-We describe the findings in a series of 4 autopsy cases of patients diagnosed with NSF. This report describes the history of renal dysfunction, exposure to gadolinium-containing contrast agents, specific laboratory parameters, and the extent of systemic involvement identified by postmortem examination.

RESULTS

-Causes of death included systemic thromboembolic disease (n = 3) and pneumonia (n = 1). Laboratory parameters and type, dose, or timing of gadolinium-containing contrast-agent exposure did not correlate with clinical findings and outcomes. All patients demonstrated cutaneous manifestations of the disease and nephrocalcinosis, with some exhibiting calcification and fibrosis of the dura, thyroid, and heart including the cardiac conduction system, on postmortem examination. Soft tissue calcification was associated with concurrent hyperparathyroidism or high serum parathyroid hormone levels.

CONCLUSIONS

-Thromboembolic disease can be a significant clinical complication of NSF. Patients with NSF may also develop characteristic histologic features of fibrosis and calcification in multiple organs, with significant morbidity and mortality. This autopsy series highlights the variability of systemic manifestations of NSF.

Estimating the reduction of urban PM10 concentrations by trees within an environmental information system for planners

Trees have been widely quoted as effective scavengers of both gaseous and particulate pollutants from the atmosphere. Recent work on the deposition of urban aerosols onto woodland allows the effect of tree planting strategies on airborne aerosol concentrations to be quantified and considered within the planning process. By identifying the potential planting locations in the local authority area, and applying them within a dispersion and deposition model, the potential magnitude of reduction in the ambient concentration of PM(10), achievable through urban tree planting, has been quantified for two UK cities. As part of the Environmental Information Systems for Planners (EISP), flow diagrams, based on planning decisions, have incorporated output from the model to make decisions on land use planning ranging from development plans and strategic planning, to development control. In this way, for any new developments that contribute to the local PM(10) level, the mitigation by planting trees can be assessed, and in some cases, reductions can be sufficient to meet air quality objectives for PM(10).

Tissue factor around dermal vessels has bound factor VII in the absence of injury

BACKGROUND

'Idling' or ongoing low-level activity of the tissue factor (TF) pathway is a postulated mechanism by which the coagulation process can become active without a lag period at sites of injury.

OBJECTIVE

To determine whether TF around cutaneous vessels has bound factor VIIa in the absence of injury, and thus could participate in the idling process.

METHODS

Immunostaining of mouse skin with antibodies against a 15-residue peptide from the sequence of mouse TF, and against the whole extracellular portion of TF.

RESULTS

The whole TF antibody recognized TF in squamous epithelium and around vessels in the dermis. By contrast, the monospecific antibody only recognized TF in the squamous epithelium, but not around vessels. We also found that biotinylated, active site-inhibited FVIIa (FVIIai) bound to tissue sections in the same areas in which TF was recognized by the monospecific antibody (squamous epithelium), but did not bind around vessels. Molecular modeling revealed that FVIIa and FX binding to TF masked a significant part of the surface of the target peptide.

CONCLUSIONS

In the aggregate, these data are most consistent with the interpretation that TF in perivascular sites has bound FVIIa, even in the absence of any injury. The presence of endogenously bound FVIIa prevents the subsequent binding of the monospecific antibody or exogenous FVIIai to perivascular TF.

Implications of enzyme kinetics

Of the many examples of oscillatory kinetic behaviour known, several are briefly reviewed, including those of glycolysis, the peroxidase-oxidase reaction and oscillations in cellular calcium concentration. It is shown that simple mathematical models employing allosteric rate laws are sufficient to explain the instability of the steady state and the appearance of sustained oscillations. The cAMP-signalling systems of cellular slime moulds and the dynamics of intracellular calcium oscillations illustrate the importance of such oscillophores to inter- and intra-cellular communication and differentiation.

Partial deletion of both the spermine synthase gene and the Pex gene in the X-linked hypophosphatemic, gyro (Gy) mouse

Gy, along with Hyp, is a dominant mutation of the normal gene Pex causing X-linked hypophosphatemia in the mouse. Hemizygous Gy male mice, however, have greater defects in survival, bodily growth, skeletal mineralization, and neurological function than those found in heterozygous Gy females or in Hyp mice. Since the gene for spermine synthase is immediately upstream of the homologous human gene PEX, we compared the effects of the Gy and Hyp mutations on both the spermine synthase gene and the Pex gene. Barely detectable levels of spermine (< 5% of normal) with elevated levels of its precursor, spermidine, were found in organs of Gy male mice compared to normal male littermates. Neither Gy females nor Hyp male mice were significantly affected. Four missing introns of the spermine synthase gene were identified in Gy male mice, suggesting extensive gene disruption. A pseudogene for spermine synthase was also identified in the mouse genome. Pex mRNA was found in several but not all tissues studied in adult normal mice. Pex mRNA was altered in both Gy and Hyp mice. All male Hyp mice were lacking the 3' end of the Pex message, whereas all male Gy mice were deficient at the 5' end. In summary, the Gy mutation is associated with a recessively expressed mutation of the spermine synthase gene, leading to spermine deficiency, and a dominantly expressed mutation of the Pex gene, leading to hypophosphatemia. Alterations in two contiguous genes in Gy may explain the additional phenotypic abnormalities present in the Gy male mouse.

Effect of disease modifying agents on the lipid profiles of patients with rheumatoid arthritis

OBJECTIVE

To determine the effect of intramuscular gold and oral hydroxychloroquine (HCQ) on the lipid profile of patients with rheumatoid arthritis (RA).

METHOD

A prospective randomised clinical trial of 12 months' duration was performed in 100 RA patients. Data on clinical and laboratory parameters of disease activity, and fasting serum lipid samples was collected at baseline and at three monthly intervals over one year.

RESULTS

The expected second line response was seen with no significant difference in efficacy between the groups at 12 months. The HCQ group had a significant overall improvement in their lipid profile while there was a trend for lipid profiles in the gold group to worsen.

CONCLUSIONS

HCQ is an effective second line agent that has beneficial effects on serum lipids. This should be taken into account when choosing a disease modifying anti-rheumatic drug in patients who suffer from RA and who have significant cardiovascular risk factors.

Interleukin 6 (IL-6) and soluble IL-2 receptor levels in patients with rheumatoid arthritis treated with low dose oral methotrexate

OBJECTIVE

To investigate the effect of oral methotrexate (MTX) on circulating levels of interleukin 6 (IL-6) and soluble IL-2 receptor (sIL-2R) in patients with rheumatoid arthritis (RA).

METHODS

We measured serum concentrations of IL-6 (n = 20) and sIL-2R (n = 16) before MTX therapy and again after 12 weeks.

RESULTS

MTX significantly reduced IL-6 and sIL-2R after 12 weeks of therapy, and although the levels remained low at 24 weeks of therapy, the reduction was not significant. Reduction in cytokine levels was paralleled by an improvement in clinical indices. Placebo treatment did not significantly alter IL-6 or sIL-2R.

CONCLUSION

MTX appears capable of cytokine modulation, although the mechanism is not clear.

Impaired proprioceptive acuity at the proximal interphalangeal joint in patients with the hypermobility syndrome

Twelve patients with the hypermobility syndrome (> or = 4 on the Beighton score) were examined to establish whether they showed any impairment of proprioception. A position matching paradigm was used which required subjects to align a finger silhouette with the kinaesthetically perceived position of their hidden index finger. Position sense at the PIP joint was found to be significantly (P < 0.0001) impaired in hypermobile patients who made larger matching errors at all angles compared to age- and sex-matched controls. The patients also demonstrated biasing in the direction of errors made when the PIP joint was positioned +/- 20 degrees away from the mid-position. These patients perceived the PIP joint to be less displaced towards the extremes of the range of movement than it really was. The mechanism underlying this impairment of proprioception remains speculative and it is not clear whether this disturbance is a cause or an effect of the hypermobility syndrome.

Lipopolysaccharides from Campylobacter jejuni associated with Guillain-Barré syndrome patients mimic human gangliosides in structure

Lipopolysaccharides extracted from Campylobacter jejuni serostrains (serotype reference strains) for serotypes O:4 and O:19 were found to have core oligosaccharides with terminal structures resembling human gangliosides GM1 and GD1a. High-molecular-weight molecules that reflected the presence of O chains were shown in immunoblots to be immunologically specific for each serostrain. The O:19 antiserum also reacted strongly with core oligosaccharides of two isolates from patients with Guillain-Barré syndrome (GBS), but the banding patterns and molecular structures were different from those of the O:19 serostrain. A neuraminobiose disaccharide unit is attached to the terminal Gal residue in one isolate, and the other isolate lacked terminal N-acetyl glucosamine and galactose with attached sialic acid so that the sialic acid residues were present in a neuraminobiose unit linked to the only remaining galactose. Analysis of the high-M(r) lipopolysaccharides of the O:19 serostrain and the two isolates from GBS patients revealed the presence of a hyaluronic acid-like polymer with disaccharide-repeating units consisting of beta-D-glucuronic acid amidated with 2-amino-2-deoxyglycerol and N-acetyl glucosamine. The results confirm a potential role for the core oligosaccharides in the etiology of GBS but also suggest that the O-chain polysaccharide may be a contributing factor.

Lipopolysaccharides of Campylobacter jejuni serotype O:19: structures of O antigen chains from the serostrain and two bacterial isolates from patients with the Guillain-Barré syndrome

An O antigenic polysaccharide was liberated from the lipopolysaccharide of high M(r) from Campylobacter jejuni serotype O:19 by acetic acid hydrolysis of the ketosidic linkage to lipid A. The structure of the polysaccharide was established in several one- and two-dimensional 1H and 13C NMR experiments, fast atom bombardment mass spectrometry and methylation linkage analysis of the permethylated glycan and its degradation products. It is concluded that the glycan is a derivative of hyaluronic acid in which the beta-D-glucuronic acid residues in the alternating sequence [-4)-beta-D-GlcA-(1-->3)-beta-D-GlcNAc-(1]n are present as amides of 2-amino-2-deoxyglycerol. Parallel experiments were performed on O antigens liberated from lipopolysaccharides of high M(r) from bacterial isolates that had been obtained from two patients who subsequently developed the Guillain-Barré syndrome. Within the limits of structural analysis by NMR spectroscopy and methylation linkage analysis, both these O antigens were identical to that from the serostrain.

Lipopolysaccharides of Campylobacter jejuni serotype O:19: structures of core oligosaccharide regions from the serostrain and two bacterial isolates from patients with the Guillain-Barré syndrome

Lipopolysaccharides from phenol-water extraction of cells of Campylobacter jejuni serotype O:19 were separated into a water-soluble gel of low M(r) and a water-soluble component of high M(r). Acetic acid hydrolysis of the ketosidic linkages to lipid A furnished respectively a core oligosaccharide, the structure of which is reported herein, and an O antigenic polysaccharide. Structural investigations were performed on the O-deacetylated lipopolysaccharide of low M(r), the liberated core oligosaccharide and the various products from removal of neuraminic acid and phosphate residues, and from the Smith degradation. It is concluded that the lipopolysaccharide from the serostrain has a core region with two types of closely related oligosaccharide chains showing striking homologies with gangliosides, the first with a single N-acetylneuraminic acid residue in an outer chain resembling GM1 and the second with two N-acetyl-neuraminic acid residues with a terminal region resembling GD1a. Similar experiments were carried out on lipopolysaccharides of low M(r) from bacterial isolates OH 4384 and OH 4382 serotyped as O:19 that had been obtained from two patients who subsequently developed the Guillain-Barré syndrome. The core oligosaccharide region of lipopolysaccharide from the former isolate differed only slightly from that of the serostrain, whereas that from the latter isolate was distinctly shorter.

An antigenic polysaccharide from Campylobacter coli serotype O:30. Structure of a teichoic acid-like antigenic polysaccharide associated with the lipopolysaccharide

A water-soluble antigenic polysaccharide of high M(r) associated with the lipopolysaccharide has been isolated from phenol-water extraction of cells of Campylobacter coli serotype O:30. The polysaccharide and oligosaccharide degradation products formed on O-dephosphorylation and by periodate oxidation followed by reduction have been investigated by one- and two-dimensional 1H, 13C, and 31P NMR. It is concluded that the antigenic polysaccharide has a teichoic acid-like structure with a poly-Ribitol phosphate, [5-Ribitol-1-P]n, backbone with side chains at O-2 of O-(6-deoxy-beta-D-talo-heptopyranosyl)-(1-->4)-(2-acetylamino-2-deoxy-beta-D- glucopyranosyl) units. The structure is unusual in Gram-negative bacteria and is unique in possessing 6-deoxy-D-talo-heptose as a constituent sugar. Evidence for the relationship of the antigenic polysaccharide to the lipopolysaccharide of low M(r) is discussed.

Chemical structure of the core region of Campylobacter jejuni serotype O:2 lipopolysaccharide

The complete structure for the core region of Campylobacter jejuni serotype O:2 lipopolysaccharide (LPS) was assigned through studies on derivatives of the liberated oligosaccharide (OS 2) and the intact LPS. Structure determinations were performed using 1H-NMR spectroscopy, methylation studies supported by fast-atom-bombardment mass spectrometry and linkage analysis by gas chromatography/mass spectrometry, Smith degradation, and oxidation with chromium trioxide. It was concluded that complete oligosaccharide chains had the following structure: [formula: see text]

Chemical structures of the core regions of Campylobacter jejuni serotypes O:1, O:4, O:23, and O:36 lipopolysaccharides

Complete structures, including the location of N-acetylneuraminic acid (Neu5Ac) residues, were assigned for the core regions of Campylobacter jejuni serotypes O:1, O:4, and O:23 and O:36 lipopolysaccharides (LPS). In continuation of earlier studies, structure determinations of liberated oligosaccharides and, where necessary, of intact LPS, were by 1H-NMR spectroscopy, Smith degradation, chromium trioxide and enzymic degradations, in conjunction with methylation studies supported by fast-atom-bombardment mass spectrometry and linkage analyses by gas chromatography/mass spectrometry. It was concluded on the basis of the following structures, in which each was linked 1-->5 to a terminal 3-deoxy-D-manno-octulosonic acid residue, that the core regions with qualitatively similar sugar compositions showed serotypic differences in one or more of their sequences, linkage types, and anomeric configurations: [formula: see text] [corrected]. The outer regions of each structure carry Neu5Ac residues linked 2-->3 to available beta-D-Galp residues and show striking similarities with various glycosphingolipids of the ganglioside family. However, Neu5Ac epitopes are not apparently involved in determining serospecificity.

Lipopolysaccharide of Campylobacter coli serotype O:30. Fractionation and structure of liberated core oligosaccharide

Lipopolysaccharide from phenol-water extraction of cells of Campylobacter coli serotype O:30 was separated as a water-insoluble gel of low M(r) from a water-soluble antigenic polysaccharide of high M(r). Acetic acid hydrolysis of the ketosidic linkages to lipid A in the lipopolysaccharide furnished a core oligosaccharide. Structural investigations were performed using 1H and 13C NMR, fast atom bombardment-mass spectrometry of permethylated derivatives, and methylation linkage analysis on the core oligosaccharide and the products of two successive Smith degradations. It is concluded that the highly branched 3-deoxy-D-manno-octulosonic acid-terminated oligosaccharide chains carried at the nonreducing end disaccharide units of beta-D-Qui3NAc-(1-->2)-beta-D-Qui3NAc (where Qui3NAc represents 3-acylamino-3,6-dideoxy-D-glucose), in which N-acyl residues were either both (R)-3-hydroxybutanoyl or both 3-hydroxy-2,3-dimethyl-5-oxoprolyl. The demonstration of these unusual features provides further evidence for a wide variety of structures within the core oligosaccharide region of lipopolysaccharides from Campylobacter sp.

Structures of the O chains from lipopolysaccharides of Campylobacter jejuni serotypes O:23 and O:36

Lipopolysaccharides of C. jejuni serotypes O:23 and O:36 have been shown to contain structurally variable O polysaccharide chains with repeating units of four closely-related types: ----3)-beta-D-GlcpNAc-(1----3)-alpha-D-Galp-(1----2)-6d-alpha-D-alt-H epp-(1---- , ----3)-beta-D-GlcpNAc-(1----3)-alpha-D-Galp-(1----2)-6d-3-Me-alpha-D-alt -Hepp- (1----, ----3)-beta-D-GlcpNAc-(1----3)-alpha-D-Galp-(1----2)-D-glycero-alpha-D-a lt-Hepp - (1----, and ----3)-beta-D-GlcpNAc-(1----3)-alpha-D-Galp-(1----2)-3-Me-D-glycero-alph a-D-alt - Hepp-(1----. Structural methods included 1H- and 13C-NMR spectroscopy, methylation linkage analysis, fast atom bombardment mass spectrometry of methylated glycans, and selective fragmentations by the Smith degradation and N-deacetylation-nitrous acid deamination.

Serological diversity and chemical structures of Campylobacter jejuni low-molecular-weight lipopolysaccharides

Low-Mr lipopolysaccharides (LPS) of Campylobacter jejuni reference strains for serotypes O:1, O:4, O:23, and O:36 were examined through the liberation of core oligosaccharides by mild acid cleavage of the ketosidic linkage of 3-deoxy-D-manno-2-octulosonic acid residues to the lipid A moiety. The liberated oligosaccharides were examined for chemical structure by compositional analysis and methylated linkage analysis in conjunction with fast atom bombardment-mass spectrometry of permethylated oligosaccharide derivatives. The results showed (i) that the LPS contained short oligosaccharide chains of branched nonrepetitive structure, to many of which N-acetylneuraminic acid residues remained attached by 2----3 linkages to 4-linked D-galactose residues in the core structure; (ii) that serotypical differences, which are not readily defined through qualitatively similar compositions, are clearly reflected in variations in linkage types and sequences of sugar residues in the outer core attached to an inner region of invariable structure; but (iii) that the presence or absence of NeuAc residues does not appear to be a basis for serotypical differences. The results also showed that oligosaccharide chains from LPS of serotypes O:1 and O:4 are distinctly different and are distinct again from those of the cross-reacting serotypes O:23 and O:36, between whose core oligosaccharide chains no differences were found. It is concluded that the structurally variable low-Mr LPS from C. jejuni show greater similarities to the lipooligosaccharides from Neisseria spp. than to the highly conserved core regions of Salmonella species. Those strains (serotypes O:23 and O:36) which also furnish high-Mr LPS are unique among gram-negative bacteria in possessing both low-Mr molecules of the Neisseria lipooligosaccharide type and high-Mr LPS of the Salmonella smooth type.