N-acetyl-D-glucosamine specific hemagglutinin receptor of Vibrio cholerae O1 in chicken erythrocyte membranes

N-Acetyl-D-glucosamine specific cell-associated hemagglutinin (HA)/lectin, previously purified from a strain of Vibrio cholerae O1, had been established as an adhesin molecule of V. cholerae O1 cells. This communication records the isolation and purification of the glycoprotein receptor of the N-acetyl-D-glucosamine specific HA of the V. cholerae O1 strain from chicken erythrocyte membranes. The most salient feature of this study is that the pretreatment of partially purified glycoprotein with purified HA could completely inhibit the hemagglutinating activity of the V. cholerae O1 strain with chicken erythrocytes.

An evaluation of computed tomography as an aid to diagnosis in patients undergoing bronchoscopy for suspected bronchial carcinoma

AIM

To determine whether computed tomography (CT) can predict the likelihood of obtaining a positive tissue diagnosis at fibreoptic bronchoscopy (FOB), or demonstrate an alternative means of achieving a tissue diagnosis, in patients presenting with a high clinical suspicion of primary bronchogenic carcinoma and an abnormal chest radiograph (CXR).

MATERIALS AND METHODS

Sixty-two patients presenting with a high clinical suspicion of carcinoma and an abnormal CXR had chest and liver CT and FOB performed. All patients subsequently had histocytological confirmation of malignancy. Features recorded from the CTs included: the site and characteristics of a mass if present, and its relationship to adjacent airways; the presence of presumed metastatic disease; and a CT prediction of the likelihood of positive FOB was made.

RESULTS

Of the patients, 41/62 (66%) had inoperable stage IIIb/IV disease. Fibreoptic biopsy yielded positive tissue diagnoses in 38/62 (61%). Computed tomography features predicting a positive FOB in this group included: ill-definition of the mass (12/15, 80%); a mass <4 cm from the origin of the nearest lobar bronchus (36/53, 68%); an endobronchial component of mass (22/24, 92%); a segmental or larger airway leading to the mass (30/35, 86%). Overall, CT had positive and negative predictive values for positive FOB of 85% and 78% respectively. The accuracy of the overall CT prediction of positive FOB was better than the accuracy of any of the individual factors. Seventeen of 62 (27%) patients had presumed metastatic disease suitable for percutaneous biopsy.

CONCLUSION

Computed tomography is useful in predicting the likelihood of achieving positive histocytology at FOB. The overall CT prediction is superior to any of the individual CT features taken alone.Bungay, H. K. (2000). Clinical Radiology 55, 554-560.

Heterogeneous signal in bone marrow on MRI of children's feet: a normal finding?

OBJECTIVE

To describe the magnetic resonance (MR) appearances of the bone marrow of children's feet and to determine their frequency and significance.

DESIGN AND PATIENTS

A review of MR studies obtained in a retrospective series of 35 children with foot pain and in a prospective series of 19 asymptomatic children was performed. The MR appearances on T1-weighted, T2-weighted and STIR sequences were assessed and the frequency of patchy areas of low signal intensity on T1-weighted and high signal intensity on T2-weighted or STIR sequences was determined and correlated with clinical features.

RESULTS AND CONCLUSIONS

Low signal intensity on T1-weighted and high signal intensity on T2-weighted and STIR sequences were seen in 63% of symptomatic and 57% of asymptomatic children. In all cases where both feet were imaged, the changes were seen bilaterally. The marrow pattern varied from multiple discrete foci to more extensive confluent areas of high signal on the STIR sequence. These appearances are frequent and represent normal variation in the growing skeleton, and should not necessarily be interpreted as a sign of pathology.

Purification of a mannose/glucose-specific hemagglutinin/lectin from a Vibrio cholerae O1 strain

A cell-associated mannose/glucose-specific hemagglutinin (MSHA) has been purified from a strain of Vibrio cholerae O1 by chromatography on a chitin column followed by affinity purification on Sephadex G100. The purified protein gave a single stained band of 40 kDa by SDS-PAGE, exhibited high affinity towards D-mannose and D-glucose but was resistant to L-fucose and N-acetyl-D-glucosamine. The purified MSHA was revealed as a globular form of protein under electron microscope. In immunodiffusion tests the purified MSHA produced a single precipitin band against homologous antisera and antisera raised against the whole cell bacteria without any reactivity towards antisera raised against the purified N-acetyl-D-glucosamine-specific lectin of the same bacterial strain. Immunogold labelling confirmed the location of hemagglutinin on the surface of the bacteria. Purified MSHA reacted strongly with sera from convalescent cholera patients in immunodiffusion tests.

The role of micturating cystourethrography in antenatally detected mild hydronephrosis

BACKGROUND

The postnatal imaging of infants with antenatally detected mild hydronephrosis remains controversial.

OBJECTIVE

Our aim was to establish the role and timing of micturating cystourethrography (MCUG) in mild hydronephrosis.

MATERIALS AND METHODS

We performed a retrospective study of 61 infants (122 kidneys) referred with an antenatal diagnosis of hydronephrosis who showed persistent postnatal dilatation. All had follow-up postnatal ultrasound (US) and MCUG performed. The degree of dilatation at each follow-up scan was recorded.

RESULTS

Of the 122 kidneys, 65 showed mild hydronephrosis. A substantial proportion of these (21.5%) demonstrated reflux. Serial US of these infants showed that the 6-week scan was the most informative and that any changes that warranted further investigation had occurred by this time.

CONCLUSION

We recommend that all infants with mild hydronephrosis should undergo MCUG. MCUG need not be delayed until 3 months but could be performed following a 6-week US scan.

Purification of a cell-associated hemagglutinin from Shigella dysenteriae type 1

A cell-associated hemagglutinin (HA) was isolated and purified from a clinical isolate of Shigella dysenteriae type 1 by affinity chromatography on a fetuin-agarose column. The purified hemagglutinin produced a single-stained protein band of around 66 kDa in sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). In an immunodiffusion test, HA-antisera produced a single precipitin band against the purified HA without exhibiting any reactivity towards lipopolysaccharide (LPS) of S. dysenteriae type 1 strain. Inhibition of the hemagglutination by the glycoproteins fetuin, asialofetuin and a sugar derivative N-acetyl-neuraminic acid but not by simple sugars, suggested the specific requirement of complex carbohydrate for binding. Electron micrographs of the purified HA revealed a morphology typical of globular protein.

Role of cell-associated N-acetyl-D-glucosamine specific haemagglutinin in the adhesion of Vibrio cholerae O1 to rabbit intestinal epithelial cells in vitro

Previously a N-acetyl-D-glucosamine specific cell-associated haemagglutinin (HA) had been purified from a Vibrio cholerae O1 strain. This study documents the role of this purified HA as an adhesin of V. cholerae O1. A significant inhibition in the adhesion of V. cholerae O1 bacterial cells to isolated rabbit intestinal brush borders (RIBB) was observed when the latter were pretreated with purified HA in ELISA. Antibody raised against purified HA and Fab (IgG) fragment of this serum inhibited adhesion of the bacteria to isolated rabbit intestinal epithelial cells (RIEC). V. cholerae O1 (both Ogawa and Inaba serovars) showed less adherence to isolated RIEC of animals immunised with the purified HA. Patients convalescing from V. cholerae O1 infection showed high ELISA titres against the purified HA indicating that it is expressed in the host during the disease process.

Antibody mediated inhibition of adhesion of Shigella dysenteriae 1 to guinea pig colonic epithelial cells in vitro

Immunoglobulin G (IgG) fractions prepared from sera of Shigella dysenteriae 1 infected patients during the acute and convalescent phases of illness were found to be effective inhibitors of adhesion of S. dysenteriae cells to guinea pig colonic epithelial cells in vitro. The adhesion could also be inhibited by whole sera, their IgG fractions, and Fab fractions prepared from sera of rabbits immunized with whole bacteria, the outer membrane (OM) and lipopolysaccharide. The adhesive capability was best inhibited by the Fab fragment of antisera of rabbits immunized with whole bacteria.

Studies on adhesion, haemagglutination and other biological properties of Vibrio cholerae O139

The adhesive capabilities of eight Vibrio cholerae O139 epidemic strains to isolated rabbit intestinal epithelial cells (RIEC) were observed to be high similar to those observed with a Vibrio cholerae O1 strain isolated from patients. Toxin production by the strains, measured by accumulation of fluid in rabbit ileal loop model, was high and the toxin was lethal as the animal expired within 6 h. Culture filtrates of the strains exhibited the presence of vascular permeability factor which produce induration and necrosis in the adult rabbit and guinea pig skin. All the strains showed high to moderate haemagglutinin titres against chicken erythrocytes and produced El Tor-like haemolysin. SDS-PAGE of the outer membrane preparation of the strains showed the presence of major protein component at 38 kDa region. The lethality of the toxin, high adhesive activity, shifting of the major outer membrane protein band and production of thermolabile haemolysin on Wagatsuma agar were the major variations of these epidemic strains from V. cholerae O1 and V. cholerae non-O1 strains isolated previously.

N-acetyl-D-glucosamine-specific lectin purified from Vibrio cholerae 01

An N-acetyl-D-glucosamine-specific cell associated hemagglutinin (HA) was isolated and purified from a strain of Vibrio cholerae 01 by chitin affinity chromatography followed by separation on Bio Gel P-150. A single stained protein band of 47 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was observed with the purified HA. HA-antisera produced a single precipitin band against the purified HA in an immunodiffusion test without exhibiting any reactivity towards purified lipopolysaccharide (LPS). Purified HA, used as solid-phase antigen in an enzyme-linked immunosorbent assay (ELISA), reacted strongly with HA-antisera but cross-reacted negligibly with antisera raised against purified LPS. Hemagglutinating activity of the purified HA was highly sensitive to N-acetyl-D-glucosamine. The immunogold-labelling method using HA-antisera confirmed the location of the HA on the surface of the bacterial cells. The HA-antisera reacted with a protein component of the homologous outer membrane preparation. A significant inhibition was observed in the adhesive capability of the V. cholerae 01 strain to isolated rabbit intestinal epithelial cells (RIEC) in vitro when the later were pre-treated with the purified HA.

Post-transplant erythrocytosis and immunosuppression with cyclosporin: a case-control study

Review of 142 renal transplant recipients treated with cyclosporin and prednisolone revealed 23 patients with post-transplant erythrocytosis. The clinical characteristics of these patients were compared with 23 cyclosporin/prednisolone-treated control subjects matched for age, sex, and duration of transplant. Erythrocytosis developed between 6 weeks and 30 months (median 12 months) after transplant. It persisted in 16 patients and resolved spontaneously in five. In two patients the decrease in haematocrit was associated with acute leukaemia in one and sudden deterioration of renal function in the other. In the study group there were fewer HLA (A, B and DR) mismatches (P less than 0.05) and greater pretransplant haematocrit (P less than 0.01) than in the control group. Other clinical factors--previous allografts, panel reactive cytotoxic antibodies, duration and type of dialysis, transplant function, pre- and post-transplant blood pressure, number of rejection episodes, cyclosporin concentration and dose, smoking habits and use of diuretics--did not differ significantly between the two groups. In our experience, erythrocytosis in cyclosporin-treated patients is a relatively common phenomenon and does not, in general, resolve spontaneously. It is unrelated to transplant function or rejection episodes but affects patients with well-matched kidneys and elevated pretransplant haematocrit values.