Incidental lymphadenopathy in renal transplantation

INTRODUCTION

Iliac lymphadenectomy is performed to provide anastomotic access during the vascular implantation procedure in renal transplantation. Iliac lymph nodes (LNs) are often enlarged, but there are no standardised guidelines for the management of incidentally enlarged LNs during transplantation. We aimed to evaluate histological findings of LNs sent for examination at our unit.

METHODS

Patients were evaluated in two distinct date cycles. In the first cycle, lymphadenectomy and histological assessment were performed at the discretion of the transplanting surgeon. In the second cycle, all incidentally enlarged LNs were sent for histological assessment, regardless of size.

RESULTS

In the first cycle (n = 76), 11 patients (14.47%) had incidentally enlarged iliac LNs on lymphadenectomy and histology showed only reactive changes. In the second cycle (n = 165), eight patients (4.85%) had incidentally enlarged LNs on lymphadenectomy. One patient was found to have mature B cell chronic lymphocytic leukaemia. The patient was referred to haematology and a "watch and wait" approach was taken, with the patient still alive at last follow-up (511 days post-transplantation).

DISCUSSION

There are currently no published guidelines on the management of incidentally enlarged iliac LNs during transplantation. Current literature suggests that clinically significant lymphadenopathy needs to be investigated in all patients. Based on our centre's experience of a 5.26% (1 in 19) positive pathological LN sampling, we recommend that all incidental LNs with suspicious features and/or that are greater than 10mm in diameter should be considered for histological, microbiological and molecular assessment as appropriate.

Inter-cluster competition and resource partitioning may govern the ecology of Frankia

Microbes live in a complex communal ecosystem. The structural complexity of microbial community reflects diversity, functionality, as well as habitat type. Delineation of ecologically important microbial populations along with exploration of their roles in environmental adaptation or host-microbe interaction has a crucial role in modern microbiology. In this scenario, reverse ecology (the use of genomics to study ecology) plays a pivotal role. Since the co-existence of two different genera in one small niche should maintain a strict direct interaction, it will be interesting to utilize the concept of reverse ecology in this scenario. Here, we exploited an 'R' package, the RevEcoR, to resolve the issue of co-existing microbes which are proven to be a crucial tool for identifying the nature of their relationship (competition or complementation) persisting among them. Our target organism here is Frankia, a nitrogen-fixing actinobacterium popular for its genetic and host-specific nature. According to their plant host, Frankia has already been sub-divided into four clusters C-I, C-II, C-III, and C-IV. Our results revealed a strong competing nature of CI Frankia. Among the clusters of Frankia studied, the competition index between C-I and C-III was the largest. The other interesting result was the co-occurrence of C-II and C-IV groups. It was revealed that these two groups follow the theory of resource partitioning in their lifestyle. Metabolic analysis along with their differential transporter machinery validated our hypothesis of resource partitioning among C-II and C-IV groups.

330 Comparing Outcomes in Right Versus Left Kidney Transplantation; A Systematic Review and Meta-Analysis

Introduction

Transplantation of right kidneys can pose technical challenges due to the short right renal vein. Whether this results in inferior outcomes remains controversial.

Method

We used Healthcare Database Advanced Search (HDAS) to identify relevant studies. Two authors independently reviewed each study. Statistical analyses were performed using random effects models and results expressed as HR or relative risk (RR) with 95% confidence intervals. Subgroup analyses were performed in kidneys from deceased donors (DD) and living donors (LD).

Results

35 studies (257,429 participants) were identified. Both deceased and living donor right kidneys were at increased risk of delayed graft function (DGF; RR = 1.10[1.07-1.12] p < 0.00001). In absolute terms, for each 100 kidney pairs of DD kidneys transplanted there are 2.72 (1.67-3.78, p < 0.00001) excess episodes of DGF in right kidneys. Graft thrombosis rate was also significantly higher in right kidneys, in both DD and LD settings (RR = 1.55[1.41-1.69] p < 0.00001). Compared to DD left kidneys, DD right kidneys were at significantly higher risk of graft failure due to technical causes (RR = 1.54[1.25-1.90], P < 0.0001). The two largest DD studies (179,124 participants) found right kidneys to have significantly poorer graft survival; time-varying analyses demonstrated this was caused by early graft losses within the first year. There was no evidence that laterality alters long term graft survival in LD or DD.

Conclusions

Right kidneys are at increased risk of early complications in both DD and LD settings, although the absolute effects are small. Improved vascular reconstruction techniques for the right renal vein, which avoid detrimental impacts on ischaemia times, are essential.

O6: EARLY ANASTOMOTIC BILIARY COMPLICATIONS AFTER LIVER TRANSPLANTATION

Introduction

Biliary leaks and anastomotic strictures are common early biliary complications (EBC) following liver transplantation. However, their impact on outcomes remains controversial and poorly described.

Method

The NHS registry on adult liver transplantation between 2006 and 2017 was retrospectively reviewed (n=8304). Multiple imputations were performed to account for missing data. Adjusted regression models were used to assess predictors of EBC, and their impact on outcomes. 35 potential variables were included, and backwards stepwise selection enabled unbiased selection of variables for inclusion in final models.

Result

EBC occurred in 9.6% of patients. Adjusted cox regression revealed that EBCs have a significant and independent impact on graft survival (Leak HR=1.325; P=0.021, Stricture HR=1.514; P=0.002, Leak plus stricture HR=1.533; P=0.034) and patient survival (Leak HR=1.218; P=0.131, Stricture HR=1.578; P<0.001, Leak plus stricture HR=1.507; P=0.044). Patients with EBC had longer median hospital stay (23 versus 15 days; P<0.001) and increased chance for readmission within the first year (56% versus 32%; P<0.001). On adjusted logistic regression the following were identified as independent risk factors for development of EBC: donation following circulatory death (OR=1.280; P=0.009), accessory hepatic artery (OR=1.324; P=0.005), vascular anastomosis time in minutes (OR=1.005; P=0.032) and ethnicity ‘other’ (OR=1.838; P=0.011).

Conclusion

EBCs prolong hospital stay, increase readmission rates and are independent risk factors for diminished graft survival and increased mortality in liver transplantation. We have identified factors that increase the likelihood of EBC occurrence; further research into interventions to prevent EBCs in these at-risk groups is vital to improve liver transplantation outcomes.

Take-home message

Using a large registry database we have shown that early anastomotic biliary complications are independent risk factors for decreased graft survival and increased mortality after liver transplantation. Research into interventions to prevent biliary complications in high risk groups are essential to improve liver transplant outcomes.

Risk factors and impact of early anastomotic biliary complications after liver transplantation: UK registry analysis

Background

Biliary leaks and anastomotic strictures are common early anastomotic biliary complications (EABCs) following liver transplantation. However, there are no large multicentre studies investigating their clinical impact or risk factors. This study aimed to define the incidence, risk factors and impact of EABC.

Methods

The NHS registry on adult liver transplantation between 2006 and 2017 was reviewed retrospectively. Adjusted regression models were used to assess predictors of EABC, and their impact on outcomes.

Results

Analyses included 8304 liver transplant recipients. Patients with EABC (9·6 per cent) had prolonged hospitalization (23 versus 15 days; P < 0·001) and increased chance for readmission within the first year (56 versus 32 per cent; P < 0·001). Patients with EABC had decreased estimated 5-year graft survival of 75·1 versus 84·5 per cent in those without EABC, and decreased 5-year patient survival of 76·9 versus 83·3 per cent; both P < 0.001. Adjusted Cox regression revealed that EABCs have a significant and independent impact on graft survival (leak hazard ratio (HR) 1·344, P = 0·015; stricture HR 1·513, P = 0·002; leak plus stricture HR 1·526, P = 0·036) and patient survival (leak HR 1·215, P = 0·136, stricture HR 1·526, P = 0·001; leak plus stricture HR 1·509; P = 0·043). On adjusted logistic regression, risk factors for EABC included donation after circulatory death grafts, graft aberrant arterial anatomy, biliary anastomosis type, vascular anastomosis time and recipient model of end-stage liver disease.

Conclusion

EABCs prolong hospital stay, increase readmission rates and are independent risk factors for graft loss and increased mortality. This study has identified factors that increase the likelihood of EABC occurrence; research into interventions to prevent EABCs in these at-risk groups is vital to improve liver transplantation outcomes.

Prospective assessment of resection margin status following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma after standardisation of margin definitions

BACKGROUND

Surgical resection remains the only curative treatment for pancreatic ductal adenocarcinoma (PDAC). The prognostic value of resection margin status following pancreatoduodenectomy (PD) remains controversial. Standardised pathological assessment increases positive margins but limited data is available on the significance of involved margins. We investigated the impact of resection margin status in PDAC on patient outcome.

METHOD

We identified all patients with PD for PDAC at one pancreatic cancer centre between August 2008 and December 2014. Demographic, operative, adjuvant therapeutic and survival data was obtained. Pathology data including resection margin status of specific anatomic margins was collected and analysed.

RESULTS

107 patients were included, all pathologically staged as T3 with 102 N1. 87.9% of patients were R1 of which 53.3% showed direct extension to the resection margin. Median survival for R0 patients versus R1<1 mm and R1 = 0 mm was 28.4 versus 15.4 and 25.1 versus 13.4 months. R1 = 0 mm status remained a predictor of poor outcome on multivariate analysis. Evaluation of individual margins (R1<1 mm) showed the SMV and SMA margins were associated with poorer overall survival. Multiple involved margins impacted negatively on outcome. SMA margin patient outcome with R1 = 1-1.9 mm was similar to R1=>2 mm.

CONCLUSION

Using an R1 definition of <1 mm and standardised pathology we demonstrate that R1 rates in PDAC can approach 90%. R1 = 0 mm remained an independent prognostic factor for overall survival. Using R1<1 mm we have shown that involvement of medial margins and multiple margins has significant negative impact on overall survival. We conclude that not all margin positivity has the same prognostic significance.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

Long-term treatment of chronic venous insufficiency of the leg with micronized purified flavonoid fraction in the primary care setting of India

Objective: This study investigates whether micronized purified flavonoid fraction (MPFF) is effective and acceptable without compression or surgical intervention for the management of chronic venous insufficiency of the leg (CVIL) in the primary care setting of a tropical country such as India.

Methods: A prospective observational study on patients with early CVIL drawn from the clinical practice of randomly selected physicians distributed across India. Patients received MPFF 1000 mg/day for six months without compression stockings or surgery. The primary outcome was a change in their CEAP (clinical, aetiological, anatomical, pathophysiological) classification of CVIL severity. Secondary outcomes were changes in leg oedema, symptom intensity and quality of life.

Results: Of the 308 patients recruited by 72 physicians, 166 (53.9%, 95% confidence interval (CI) 48.3-59.5) had regression in the CEAP severity stage. Mean leg circumference in those with oedema decreased by 2 cm (95% CI 1.7-2.3, P <0.05). Patient-assessed mean percentage decrease in symptom intensity was 32.3 for cramps (28.9-35.7, P <0.01); 32.4 for heaviness (29.8-35.7, P <0.01); 28.2 for pain (25.6-30.8, P <0.01); and 21.5 for swelling (18.7-24.3, P <0.01). Quality of life improved by 21.7% (16.9-26.5, P <0.01) in the physical domains, 25.9% (20.8-31.0, P <0.01) in the social domains, and 19.2% (14.7-23.7, P <0.01) in the psychological domains.

Conclusions: When used alone, MPFF was effective and acceptable for the management of CVIL in primary care. This may be useful in tropical climates where compliance with compression stockings is poor and access to surgery limited.

121 EXPRESSION OF HYALURONAN SYSTEM COMPONENTS IN THE EARLY PREGNANT OVINE ENDOMETRIUM

Hyaluronan (HA; hyaluronic acid), a member of glycosaminoglycans (GAG) family, is the main polysaccharide and is expressed in almost all tissues including those of the reproductive tract. Three different hyaluronic acid-synthase (HAS) enzymes, HAS1, HAS2, and HAS3, synthesise HA. The action of HA depends on its molecular size and its cell surface receptor (CD44). Hyaluronidases (HYAL) are a group of enzymes, HYAL-1 and HYAL-2, that degrade HA. Roles of the HA system in reproductive events include oocyte maturation, fertilization, and implantation. It is also known that ovarian steroids, specifically progesterone, regulate the HA system in the endometrium. Moreover, HA-mediated cell signalling participates in embryonic development. The aim of this study was to evaluate expression of the HA system at the mRNA level in the early pregnant ovine endometrium at pre-implantation stage. Therefore, endometrial tissue samples were collected on Day 13 of the oestrous cycle (n = 10) and pregnancy (n = 14). Relative mRNA expression levels of HA system genes were quantified using quantitative RT-qPCR. Data were analysed using one-way ANOVA and l.s.d. test. All of the studied components of the HA system (HAS1, HAS2, HAS3, HYAL1, HYAL2, and CD44) were expressed in the ovine endometrium. Steady-state mRNA levels of HAS1, HYAL1, HYAL2, and CD44 were not significantly different between cyclic and early pregnant ovine endometrium on Day 13. However, expression of HAS2 and HAS3 appeared to be down-regulated in early pregnancy. Considering that both cyclic and pregnant endometrium on Day 13 is under the influence of progesterone, detected differential regulation of some components of HA system in the ovine endometrium may be directly related to the effects of the presence of an embryo. The role of the HA system in ovine endometrium at later stages of pregnancy warrants further investigation. Partially funded by TUBITAK-112R022 to ZK and SUBAP to AG.

Prevalence of Tinea capitis in school going children in Kolkata, West Bengal

Background:

In recent years the incidence of Tinea capitis, infection of scalp by dermatophytes, has increased in United Kingdom and North America. The trend may be similar in India. The objective of this study is to find the prevalence of Tinea capitis in school going urban children in Kolkata, West Bengal state.

Materials and Methods:

The present study is a cross-sectional study conducted in a government higher primary school in Kolkata.

Results:

Totally 505 students were screened and 52 were diagnosed to have Tinea capitis by clinical examination, giving a prevalence rate of 10% among school children. Prevalence rates among the age groups of 6–8, 9–11 and 12–14 years were almost the same, ranging from 9 to 11%. The prevalence rate was significantly high among the boys (14%). There was no significant difference in prevalence of infection among coconut oil users and castor oil users. Measures of general hygiene were similar among those who were infected with Tinea capitis and those who were not. The commonest clinical type of infection found was dull grey patches. Itching with hair loss was the major symptom and most of the infected children had cervical lymphadenopathy. The potassium hydroxide studies revealed endothrix spores in majority of samples.

Conclusion:

Tinea capitis in prevalent in school going urban children in Kolkata, West Bengal state and necessary measures must be undertaken to curtail this incidence.

I19 Antiviral actions of the interferon-inducible IFIT proteins

Antiviral actions of the interferon-inducible IFIT proteins

Ganes Sen, Volker Fensterl, Jamie Wetzel

The ISG56/IFIT genes are a multi-member family of interferon-inducible genes; there are four members in human and three in mouse. All IFIT proteins contain multiple TPR motifs which mediate protein-protein interactions. Some, but not all, members inhibit initiation of protein synthesis by binding to the translation initiation factor eIF-3 or by binding to the 5′ end of the mRNA. The murine Ifit1 encodes P56, Ifit2 encodes P54 and Ifit3 encodes P49. For investigating the biological functions of the murine Ifit proteins, we have recently generated several knock-out mice. Challenging Ifit1-/- and Ifit2-/- mice with various viruses have revealed their strong, but selective, antiviral properties. Ifit1-mediated host restriction was shown to be evaded by 2′-O-methylation of viral mRNAs. Flavivirus (West Nile Virus), vaccinia virus and coronavirus mutants, that lack 2′-O-methylation of their mRNAs, were growth-restricted in Wt, but not in Ifit1-/-, cells and mice. Further studies revealed that the action of Ifit1 on WNV replication is highly manifested in CNS infection, a deficiency of Ifit1 causing increased neuronal death in infected mice. Ifit2, on the other hand, blocked neuro-pathogenesis caused by intranasal infection with the rhabdovirus, VSV. All Ifit proteins were induced in the CNS of the infected mice, but Ifit1-/- mice were not more susceptible than Wt mice and most of the infected mice survived. In contrast, all Ifit2-/- mice died from neuro-pathogenesis; VSV replicated efficiently in the neurons of these mice. However, there was no effect on pathogenesis by another neuro-tropic virus, EMCV. Moreover, VSV did not replicate efficiently in the liver or the lung of infected Ifit2-/- mice and in vitro, in MEF or primary fetal neurons, the sensitivity of VSV replication to IFN-treatment was similar in Wt and Ifit2-/- cells. These results demonstrated the existence of tissue-, virus- and ISG-specific antiviral actions of interferon.

The HPB Clinic: Do Patients Want a Copy of Their Clinic Letter?

The NHS plan published by the Department of Health (DH) in 2000 recommended that patients should receive copies of all clinician-generated correspondence written about them. Concerns from many groups delayed widespread implementation of the policy and a committee set up under the NHS Modernisation Board recommended that further research was required in this area prior to rolling out the policy fully. Good practice guidelines on copying letters to patients were subsequently produced by the DH in 2001.

Isolated splenic metastasis from renal cell carcinoma: case report and review

This report presents the case of a 70-year-old woman with a previous history of a left nephrectomy for renal cell carcinoma (RCC), who developed general malaise and fatigue. Abdominal computed tomography demonstrated an enhancing 6 × 7 cm necrotic lesion in the lower pole of the spleen suggestive of a metastasis. Given the highly suspicious nature of the lesion we proceeded to splenectomy. The tumour did not breach the splenic capsule, and there was no local diaphragmatic involvement. The mass was concluded to be a true metastasis of the original RCC rather than local recurrence of the disease. The causes of isolated solid splenic lesions are wide and varied, however a past or present history of malignancy should lead to a high index of suspicion for a splenic metastasis. We report an extremely unusual case of spread from a RCC.

14-Deoxyandrographolide desensitizes hepatocytes to tumour necrosis factor-alpha-induced apoptosis through calcium-dependent tumour necrosis factor receptor superfamily member 1A release via the NO/cGMP pathway

BACKGROUND AND PURPOSE

Andrographis paniculata (AP) has been found to display hepatoprotective effect, although the mechanism of action of the active compounds of AP in this context still remains unclear. Here, we evaluated the hepatoprotective efficacy of 14-deoxyandrographolide (14-DAG), a bioactive compound of AP, particularly its role in desensitization of hepatocytes to tumour necrosis factor-alpha (TNF-alpha)-induced signalling of apoptosis.

EXPERIMENTAL APPROACH

TNF-alpha-mediated ligand receptor interaction in hepatocytes in the presence of 14-DAG was studied in vitro in primary hepatocyte cultures, with the help of co-immunoprecipitation, confocal microscopy and FACS analysis. Events associated with 14-DAG-induced TNFRSF1A release from hepatocytes were determined using immunoblotting, biochemical assay and fluorimetric studies. Pulse-chase experiments with radiolabelled TNF-alpha and detection of apoptotic nuclei by terminal transferase-mediated dUTP nick-end labelling were performed under in vivo conditions.

KEY RESULTS

14-DAG down-regulated the formation of death-inducing signalling complex, resulting in desensitization of hepatocytes to TNF-alpha-induced apoptosis. Pretreatment of hepatocytes with 14-DAG accentuated microsomal Ca-ATPase activity through induction of NO/cGMP pathway. This resulted in enhanced calcium influx into microsomal lumen with the formation of TNFRSF1A-ARTS-1-NUCB2 complex in cellular vesicles. It was followed by the release of full-length 55 kDa TNFRSF1A and a reduction in the number of cell surface TNFRSF1A, which eventually caused diminution of TNF-alpha signal in hepatocytes.

CONCLUSION AND IMPLICATION

Taken together, the results demonstrate for the first time that 14-DAG desensitizes hepatocytes to TNF-alpha-mediated apoptosis through the release of TNFRSF1A. This can be used as a strategy against cytokine-mediated hepatocyte apoptosis in liver dysfunctions.

A comparison of three fibrinolytic agents in prevention of intra-abdominal adhesions

PURPOSE

Three different drugs affecting the coagulation process at various stages were studied for their effectiveness in preventing intra-peritoneal adhesion formation in rats.

MATERIAL AND METHODS

Forty female Wistar-Albino rats divided into four groups based on the drugs administered during the experimental laparotomy and caecal abrasion: the control group--no drug administered, the intra-peritoneal tissue plasminogen activator (TPA) group, the subcutaneous fondaparinux sodium (FS) group and the intra-peritoneal activated drotrecogin alfa (ADA) group. After two weeks, intra-peritoneal adhesions were macroscopically and microscopically scored.

RESULTS

The macroscopic scores of the three groups were similar but all lower than the control group (p = 0.002). Inflammation (p = 0.023) and fibrosis (p = 0.019) scores were lower in just the ADA group when compared to the control group.

CONCLUSIONS

All three agents were effective in preventing adhesions when compared to the control group. Nevertheless, ADA seemed the most effective except when considering clinical applicability, in which case FS seemed to offer the greatest advantage.

Synthesis, Raman, FT-IR, NMR spectroscopic characterization, antimicrobial activity, cytotoxicity and DNA binding of new mixed aza-oxo-thia macrocyclic compounds

Series of new mixed aza-oxo-thia macrocyclic ligands 1,9(2,6)-ditriazina-2,8,10,16-tetraaza-3,7,11,15-tetraoxo-5,13-dithia-cyclohexadecaphan-1(4),9(4)-diphenyl (L(1)); 1,10(2,6)-ditri azina-2,9,11,18-tetraaza-3,8,12,17-tetraoxo-5,6,14,15-tetrathia-cyclooctadecaphan-1(4),10(4)-diphenyl (L(2)); 1,11(2,6)-ditriazina-2,10,12,20-tetraaza-3,9,13,19-tetraoxo-6,16-dithia-cyclocosa-phan-1(4),11(4)-diphenyl (L(3)); 1,12(2,6)-ditriazina-2,11,13,22-tetraaza-3,10,14,21-tetraoxo-6,7,17,18-tetrathia-cyclodocosaphan-1(4),12(4)-diphenyl (L(4)) were synthesised. The structural features of the compounds have been studied by elemental analyses, Mass, FT-Raman, FT-IR, (1)H and (13)C NMR spectroscopy. The antimicrobial activities of the ligands were evaluated using disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimal inhibitory concentration (MIC) dilution method, against several bacteria and yeast cultures. The obtained results from both methods were assessed in side-by-side comparison with commercial antibacterial and antifungal agents. In most cases, the compounds show strong antifungal activity in the comparison tests. Cytotoxic activities of the ligands against two different human cancer cell lines, stomach (23132/87) and lung (A549) were determined by MTT assay. DNA fragmentation assay tested cell lines were used to analyze the DNA ladder formation which is a characteristic of apoptotic cell death. The binding of the ligands with calf thymus DNA (CT-DNA) has also been investigated by absorption spectroscopy.

The intersections of gender and class in health status and health care

It is increasingly recognized that different axes of social power relations, such as gender and class, are interrelated, not as additive but as intersecting processes. This paper has reviewed existing research on the intersections between gender and class, and their impacts on health status and access to health care. The review suggests that intersecting stratification processes can significantly alter the impacts of any one dimension of inequality taken by itself. Studies confirm that socio-economic status measures cannot fully account for gender inequalities in health. A number of studies show that both gender and class affect the way in which risk factors are translated into health outcomes, but their intersections can be complex. Other studies indicate that responses to unaffordable health care often vary by the gender and class location of sick individuals and their households. They strongly suggest that economic class should not be analysed by itself, and that apparent class differences can be misinterpreted without gender analysis. Insufficient attention to intersectionality in much of the health literature has significant human costs, because those affected most negatively tend to be those who are poorest and most oppressed by gender and other forms of social inequality. The programme and policy costs are also likely to be high in terms of poorly functioning programmes, and ineffective poverty alleviation and social and health policies.

Management strategies in isolated pancreatic trauma

AIM

In the absence of damage to other organs, pancreatic injury is rare. We have reviewed our experience with isolated pancreatic injury.

METHODS

Patients treated for isolated pancreatic trauma at our unit were identified prospectively and then retrospectively entered onto a database. The mode of presentation, mechanism of injury and management strategies were reviewed.

RESULTS

Seven male and four female patients, median age 30 years (range 13-51 years) were treated. All suffered blunt abdominal trauma with different mechanisms of injury, each being characterised by a direct blow to the central abdomen. In two patients, somatostatin analogue treatment used as primary treatment resulted in early resolution of symptoms and signs. Six patients underwent surgery at various stages post-injury. At a median follow-up of 58 months (range 22-106 months), eight patients are asymptomatic, two patients have chronic pain following distal pancreatectomy and one patient has occasional discomfort.

CONCLUSION

Confirmation of the mechanism of trauma and suspicion of pancreatic injury are essential for early diagnosis and appropriate management. Early contrast computed tomography examination is vital in the recognition of these injuries. Somatostatin analogue therapy may have an important role in the treatment regimen, especially when patients present early after sustaining a pancreatic injury. Only selected patients require open surgery.

Comparison of multislice computed tomography and endoscopic ultrasonography with operative and histological findings in suspected pancreatic and periampullary malignancy

BACKGROUND

This study compared multislice computed tomography (MSCT) with endoscopic ultrasonography (EUS) in the diagnosis and staging of pancreatic and periampullary malignancy.

METHODS

Data were collected prospectively on patients having MSCT and EUS for suspected pancreatic and periampullary malignancy.

RESULTS

Eighty-four patients had MSCT and EUS, of whom 35 underwent operative assessment (29 resections). In assessing malignancy, there was no significant difference between MSCT and EUS, and agreement was good (82 per cent, kappa = 0.49); the sensitivity and specificity of MSCT were 97 and 87 per cent, compared with 95 and 52 per cent respectively for EUS (P = 0.264). For portal vein/superior mesenteric vein invasion, MSCT was superior (P = 0.017) and agreement was moderate (72 per cent, kappa = 0.42); the sensitivity and specificity were 88 and 92 per cent for MSCT, and 50 and 83 per cent for EUS. For resectability, there was no significant difference and agreement was good (78 per cent, kappa = 0.51). EUS had an impact on the management of 14 patients in whom MSCT suggested benign disease or equivocal resectability.

CONCLUSION

MSCT is the imaging method of choice for pancreatic and periampullary tumours. Routine EUS should be reserved for those with borderline resectability on MSCT.

Crystal Structure of the 2′-Specific and Double-Stranded RNA-Activated Interferon-Induced Antiviral Protein 2′-5′-Oligoadenylate Synthetase

2′‐5′‐oligoadenylate synthetases are interferon‐induced, double‐stranded RNA‐activated antiviral enzymes which are the only proteins known to catalyse 2′‐specific nucleotidyl transfer. This first crystal structure of a 2′‐5′‐oligoadenylate synthetase reveals a structural conservation with the 3′‐specific poly(A) polymerase that, coupled with structure‐guided mutagenesis, supports a conserved catalytic mechanism for the 2′‐ and 3′‐specific nucleotidyl transferases. Comparison with structures of other superfamily members indicates that the donor substrates are bound by conserved active site features while the acceptor substrates are oriented by nonconserved regions. The 2′‐5′‐oligoadenylate synthetases are activated by viral double‐stranded RNA in infected cells and initiate a cellular response by synthesizing 2′‐5′‐oligoadenylates, that in turn activate RNase L. This crystal structure suggests that activation involves a domain–domain shift and identifies a putative dsRNA activation site that is probed by mutagenesis. We demonstrated that this site is required both for the binding of dsRNA and for the subsequent activation of OAS. This RNA‐binding site is different from known RNA‐binding site; rather than forming a defined three‐dimensional domain, it is located at the interface of the two major domains in OAS. This novel architecture ensures that the dsRNA helix can make simultaneously contact with both domains of OAS and ensure the subsequent structural rearrangement leading to the activation of OAS. Our work provides structural insight into cellular recognition of double‐stranded RNA of viral origin and identifies a novel RNA‐binding motif.

Familial Currarino syndrome presenting with peripheral primitive neuroectodermal tumour arising with a sacral teratoma

This report illustrates a rare genetic disorder, Currarino syndrome, in association with an unusual malignant transformation to a peripheral primitive neuroectodermal tumour within a sacral teratoma. The triad of features consists of a presacral mass, partial sacral agenesis and anorectal anomalies. The most common presentation is constipation. In this case there was a history of constipation, teratomas and spinal abnormalities in many of the family members over three generations. Detailed family history taken at time of initial presentation may have prevented delay in diagnosis and averted the need for intensive treatment, which may well cause late sequelae.

Increase in serum bilirubin levels in obstructive jaundice secondary to pancreatic and periampullary malignancy--implications for timing of resectional surgery and use of biliary drainage

BACKGROUND

Routine preoperative biliary drainage in cases of jaundice secondary to pancreatobiliary malignancy is associated with a significant risk of complications, failure and stent occlusion. It may be possible to avoid biliary drainage in those patients who are not deeply jaundiced.

AIMS

To measure presenting serum bilirubin and its rate of increase in patients with malignant obstructive jaundice. To predict the urgency with which surgery should be performed to avoid preoperative biliary drainage.

PATIENTS AND METHODS

Prospective data collection for all pancreatic and periampullary malignancies over a period of 18 months was carried out. Serum bilirubin levels before successful drainage were recorded. Rates of increase in bilirubin and the number of days for bilirubin to reach different thresholds were calculated.

RESULTS

Of 111 patients, 66 (59%) had resectable disease on imaging investigations. Median serum bilirubin on presentation was 160 micromol/l. Median increase was 13.1 micromol/l/day or approximately 100 micromol/l/week. The predicted number of days for bilirubin levels to reach a variety of thresholds varied significantly. For a patient presenting with a serum bilirubin of 160 micromol/l, the mean number of days for it to rise to 200 micromol/l, 300 micromol/l, 400 micromol/l and 500 micromol/l was 3, 13, 22 and 31 days, respectively.

CONCLUSIONS

There is a variable window of opportunity in jaundiced patients with pancreatic and periampullary malignancy during which surgery may be performed to avoid biliary drainage procedures, depending on the threshold for operating on the jaundiced patient.

Herniography (peritoneography) for diagnosis of Spigelian hernia

BACKGROUND

Spigelian hernia is a rare clinical condition. It is difficult to diagnose in absence of obvious clinical signs. Ultrasound scan, cross-sectional imaging and contrast studies like herniography have been widely used for detecting occult abdominal wall hernias in symptomatic patients.

AIM AND METHODS

We present our experience of detecting a clinically occult Spigelian hernia in a 56-year-old symptomatic male patient, who had concomitant left sided inguinal and Spigelian hernias. In this patient, the Spigelian hernia was not detected on ultrasound scan. We also present a review of literature on the role of herniography in the diagnosis of this rare condition.

RESULTS AND CONCLUSION

Herniography is a sensitive investigation for evaluation of occult hernias. However, it is an invasive contrast study and therefore must be used selectively. Non-invasive real-time imaging like ultrasonography remains the first line of investigation for detecting occult hernias.

The role of calpain and calpastatin in the catabolism of erythrocyte-membrane proteins during anaemia in hamsters (Mesocricetus auretus) infected with Leishmania donovani

The anaemia associated with visceral leishmaniasis is accompanied by altered Ca(2+) homeostasis and degradation of the cytoskeletal and integral proteins of the erythrocytic membrane. In the present study, such changes were followed in hamsters that were anaemic as the result of their experimental infection with Leishmania donovani. At each stage of the infection, the blood concentration of haemoglobin was found to be negatively correlated with the concentration of Ca(2+) (R(2) = 0.91), the percentage of erythrocytes with Heinz bodies (R(2) = 0.98) and thiol depletion (R(2) = 0.96) in the erythrocytes. Calpain (Ca(2+)-activated protease; EC 3.4.22.17) and its natural inhibitor calpastatin are known to regulate the catabolism of membrane structural proteins. Densitometric scanning of SDS-PAGE gels showed that erythrocytic membranes from infected hamsters contained less calpain and calpastatin than those from control animals. The level of calpain autolysis was found to increase as the infection progressed. The addition of purified calpain (from control hamsters) to erythrocyte ghosts caused greater degradation of the membranes of erythrocytes from infected animals than of the corresponding membranes from control animals. Calpastatin from the control hamsters was more effective, at inhibiting calpain-induced membrane proteolysis, than calpastatin from the infected animals. The results indicate that the Ca(2+)-activated protease and its inhibitor are involved in the degradation of erythrocytic membranes observed during visceral leishmaniasis.

Role of CD5 in growth regulation of B-1 cells

CD5 is a membrane glycoprotein that is expressed on a subset of B lymphocytes called B-1 cells, thymocytes and T cells. The CD5+ B-1 cells are normally unresponsive to surface Ig receptor induced growth signals unless the CD5 gene is deleted or sequestered away. Here we show that CD5 mediated negative regulation is unique to B cell receptor (BCR) signaling. The CD5 molecule in normal B-1 cells is constitutively tyrosine phosphorylated and associates specifically with SHP-1, an SH2 domain containing protein tyrosine phosphatase. CD5 promotes a prolonged interaction between BCR and SHP-1, which may be inhibitory to BCR signaling. CD5 was shown to modulate the function of autoantibody producing B cells in transgenic mice expressing anti-DNA antibodies.

Oxidative damage of erythrocytes: a possible mechanism for premature hemolysis in experimental visceral leishmaniasis in hamsters

Visceral leishmaniasis is accompanied by severe anemia and pancytopenia. Reactive oxygen species are known to contribute to the pathogenesis of several red blood cell (RBCs) disorders. The present study reveals the extent of oxidative stress and the efficacy of the primary antioxidant system in erythrocytes of hamsters in the progressive anemic response at different stages of leishmanial infection. Increased intracellular precipitation of Heinz bodies secondary to oxidative denaturation of hemoglobin and enhanced formation of malonyldialdehyde suggest oxidative damage of erythrocytes, both in the hemoglobin and cell membrane, respectively. Decreased activities of superoxide dismutase and catalase in the infected animals indicate the generation of O2*- and H2O2, which in turn may produce the highly reactive *OH species. Decreases in the reduced glutathione level along with the decreased activities of glutathione reductase and glutathione peroxidase point to a deficient antioxidant defense system during the post-infection period. Accentuated degradation of both cytoskeletal and integral membrane proteins after 3 months of infection may eventually lead to membrane destabilization and early lysis of erythrocytes in experimental visceral leishmaniasis.

Role of linkage specific 9-O-acetylated sialoglycoconjugates in activation of the alternate complement pathway in mammalian erythrocytes

Substitution of the -OH group at C-9 of sialic acid by an O-acetyl ester has been suggested to modify various biological phenomena that are regulated by sialic acids. Amongst them, enhancement of erythrocyte lysis by 9-O-acetylated sialic acid determinants through modulation of the alternate pathway of complement has been extensively studied on murine erythrocytes [1]. A variable expression of linkage specific 9-O-acetylated sialoglycoconjugates as defined by the lectinogenic epitope of Achatinin-H namely 9-O-acetylated sialic acid alpha2-->6Gal NAc was identified on rabbit, guinea pig, hamster, rat, mouse and human erythrocytes. This differential expression of linkage specific 9-O-acetylated sialoglycoconjugates strongly correlated with the susceptibility of mammalian erythrocytes to lysis by the alternate pathway of complement. Additionally, low levels of antibodies directed against O-acetylated sialic acids in these mammalian species suggested that these constitutively present determinants have low immunogenicity. Taken together, our results indicate that complement mediated hemolysis depends not simply upon the extent of surface 9-O-acetylated sialic acids present but more importantly upon the specific linkage.

Interaction of ascorbate and alpha-tocopherol enhances antioxidant reserve of erythrocytes during anemia in visceral leishmaniasis

Visceral leishmaniasis (V.L.) is associated with enhanced lipid peroxidation along with impaired function of antioxidant defense system in erythrocytes. The effect of chronic treatment with ascorbate and alpha-tocopherol was studied on erythrocytes in hamsters infected with Leishmania donovani. Combination treatment with both antioxidants proved to be a potential suppressor of lipid hydroperoxide formation as well as hypotonic osmotic lysis during the leishmanial infection. Positive correlations between the depleted levels of erythrocyte ascorbate, GSH and alpha-tocopherol exhibit proportionate alterations in the nonenzymatic antioxidant levels at different stages of infection. Indirect measurement of transmembrane electron transfer as ferricyanide reduction suggests an active participation of endogenous contents of ascorbate and alpha-tocopherol in the protection against oxidative damage of membrane lipids. Cooperative behavior of both antioxidants in the ferricyanide reducing capacity was further evinced by resealing the ghosts in presence of exogenous ascorbate and alpha-tocopherol. Furthermore, intravesicular ascorbate serves in the defense of extravesicular ferricyanide induced oxidation of endogenous alpha-tocopherol. The results suggest an interacting role of ascorbate and alpha-tocopherol in maintaining the antioxidant reserve of erythrocytes during anemia in V.L.

Novel function of phosphoinositide 3-kinase in T cell Ca2+ signaling. A phosphatidylinositol 3,4,5-trisphosphate-mediated Ca2+ entry mechanism

This study presents evidence that phosphoinositide (PI) 3-kinase is involved in T cell Ca(2+) signaling via a phosphatidylinositol 3,4, 5-trisphosphate PI(3,4,5)P(3)-sensitive Ca(2+) entry pathway. First, exogenous PI(3,4,5)P(3) at concentrations close to its physiological levels induces Ca(2+) influx in T cells, whereas PI(3,4)P(2), PI(4, 5)P(2), and PI(3)P have no effect on [Ca(2+)](i). This Ca(2+) entry mechanism is cell type-specific as B cells and a number of cell lines examined do not respond to PI(3,4,5)P(3) stimulation. Second, inhibition of PI 3-kinase by wortmannin and by overexpression of the dominant negative inhibitor Deltap85 suppresses anti-CD3-induced Ca(2+) response, which could be reversed by subsequent exposure to PI(3,4,5)P(3). Third, PI(3,4,5)P(3) is capable of stimulating Ca(2+) efflux from Ca(2+)-loaded plasma membrane vesicles prepared from Jurkat T cells, suggesting that PI(3,4,5)P(3) interacts with a Ca(2+) entry system directly or via a membrane-bound protein. Fourth, although D-myo-inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4, 5)P(4)) mimics PI(3,4,5)P(3) in many aspects of biochemical functions such as membrane binding and Ca(2+) transport, we raise evidence that Ins(1,3,4,5)P(4) does not play a role in anti-CD3- or PI(3,4,5)P(3)-mediated Ca(2+) entry. This PI(3,4,5)P(3)-stimulated Ca(2+) influx connotes physiological significance, considering the pivotal role of PI 3-kinase in the regulation of T cell function. Given that PI 3-kinase and phospholipase C-gamma form multifunctional complexes downstream of many receptor signaling pathways, we hypothesize that PI(3,4,5)P(3)-induced Ca(2+) entry acts concertedly with Ins(1,4,5)P(3)-induced Ca(2+) release in initiating T cell Ca(2+) signaling. By using a biotinylated analog of PI(3,4,5)P(3) as the affinity probe, we have detected several putative PI(3,4,5)P(3)-binding proteins in T cell plasma membranes.

Altered calcium homeostasis and membrane destabilization in erythrocytes of hamsters infected with Leishmania donovani

Homeostatic mechanisms regulating intracellular concentrations of Ca2+ at a low level are prerequisites for maintaining the integral and cytoskeletal structure of erythrocytes under normal physiological conditions. The present study was undertaken to assess the contribution of Ca2+ homeostasis in modifying red-cell stability in hamsters, during the anaemia caused by Leishmania donovani. Erythrocytes from the infected animals became increasingly fragile as infection progressed. This fragility may be the result of a gradual change in membrane permeability, as indicated by enhanced uptake of 45Ca2+. The increase in cytosolic Ca2+ and decrease in membrane-bound Ca2+ observed indicate the release of Ca2+ from the membrane store, leading to [Ca2+]i accumulation in the later stages of the post-infection period. Decline in the efficacy of Ca(2+)-effluxing enzyme may also contribute to the enhanced [Ca2+]i level, with subsequent degradation of membrane proteins in the erythrocytes of the infected animals. Marked inhibition of proteolytic degradation by the Ca(2+)-dependent thiol protease inhibitor leupeptin, with concomitant thiol depletion, indicates the involvement of Ca(2+)-induced thiol protease in the observed degradation of membrane proteins. The results indicate that an altered Ca2+ homeostasis in erythrocytes following leishmanial infection causes enhanced cellular accumulation of Ca2+, which in turn may lead to haemolysis in experimental visceral leishmaniasis.

Negative regulation of antigen receptor-mediated signaling by constitutive association of CD5 with the SHP-1 protein tyrosine phosphatase in B-1 B cells

CD5, a membrane-associated glycoprotein, has been shown to negatively regulate antigen receptor-mediated growth responses in peritoneal B lymphocytes, thymocytes and mature T cells. The CD5-expressing peritoneal B cells (B-1) that are normally unresponsive to B cell receptor (BCR)-mediated growth signals mount a proliferative response to BCR cross-linking if the CD5 gene is deleted or if the CD5 molecule is sequestered away from the BCR. SHP-1, a cytosolic protein tyrosine phosphatase, has also been implicated in the negative regulation of antigen receptor-mediated signaling. The present study shows that SHP-1 is constitutively associated with the BCR in B-1 cells. This association is mediated in part by CD5, as it is reduced substantially after antigen receptor ligation in CD5(-/-) B-1 cells, and upon sequestration of CD5 from the antigen receptor complexes in wild-type B-1 cells. Prior cross-linking of CD5 also restores a normal calcium mobilization response as well as NF-kappaB activation in B-1 cells. These data support a model whereby CD5 negatively regulates antigen receptor-mediated growth signals by recruiting SHP-1 into the BCR complex in B-1 cells.

Bacterial lipopolysaccharide induced B cell activation is mediated via a phosphatidylinositol 3-kinase dependent signaling pathway

Bacterial lipopolysaccharide (LPS) is a potent stimulant of B cells and macrophages. LPS induces B cell proliferation and differentiation into antibody secreting cells. In addition, LPS also stimulates IL-6 secretion in mature B cells and in immature B cell lines such as WEHI-231. Although sufficient literature is available on LPS induced signaling events in monocytes and macrophages, the mechanisms involved in LPS induced B cell activation are not well understood. In this report, it is shown that both LPS mediated B cell proliferation and IL-6 secretion are dependent on phosphatidylinositol 3-kinase (PI 3-kinase) signaling pathways. The B cell specific co-receptor, CD19 is not tyrosine phosphorylated in LPS stimulated B cells. Thus, in contrast to B cell antigen receptor (BCR) signaling, the activation of PI 3-kinase appears not to be related to the recruitment of PI 3-kinase to tyrosine phosphorylated CD19. This is the first demonstration of the importance of PI 3-kinase signaling pathway in LPS mediated B lymphocyte activation.

Antibody responses in melanoma patients immunized with an anti-idiotype antibody mimicking disialoganglioside GD2

We initiated a clinical trial for patients with advanced malignant melanoma treated with an anti-idiotype antibody that mimics the disialoganglioside GD2. We report the clinical and immune responses of the first 12 patients entered into this trial. Patients received 1-, 2-, 4-, or 8-mg doses of the anti-idiotype antibody mixed with 100 microg of QS-21 adjuvant every other week, four times, and then monthly. Twelve patients have been on trial for 2-23 months, and all of them have generated immune responses. Patients were removed from the study if they demonstrated disease progression. Hyperimmune sera from all 12 patients revealed an anti-anti-idiotypic Ab3 response, as demonstrated by the inhibition of Ab2 binding to Ab1 by patients' immune sera. To further test the anti-anti-idiotypic response, patients' Ab3 antibodies were affinity purified on Sepharose 4B columns containing adsorbed immunizing anti-idiotype immunoglobulin. Purified Ab3 of all patients studied inhibited binding of Ab1 to a GD2-positive cell line. Purified Ab3 also inhibited binding of Ab1 to purified GD2, in a manner comparable to equal quantities of purified Ab1. The patient Ab3 was truly an Ab1' because it specifically bound to purified disialoganglioside GD2. The isotypic specificity of the Ab3 antibody was predominantly IgG, with only minimal IgM. The predominant IgG subclass was IgG1, with approximately equal quantities of IgG2, IgG3, and IgG4. These Ab3 antibodies reacted specifically with tumor cells expressing GD2 by immune flow cytometry and immunoperoxidase assays. Five patients' Ab3 antibodies studied for antibody-dependent cellular cytotoxicity were positive. One patient had a complete clinical response, with resolution of soft tissue disease, and six patients had stable disease, ranging from 9 to 23 months, and are being continued on vaccine therapy. Toxicity consisted of local reaction at the site of the injection, including induration and pain that generally resolved within a few days. Mild fever and chills were observed in 75% of the patients but rarely required acetaminophen. There was no additional toxicity, including abdominal pain that was previously seen with infusion of murine monoclonal anti-GD2 antibody. Current trials include patients with stage III melanoma and small cell lung cancer. Future trials will attempt to enhance the antitumor response by the addition of interleukin 2, granulocyte macrophage colony-stimulating factor, and other cytokines, together with the 1A7 vaccine.

Induction of IgG antibodies by an anti-idiotype antibody mimicking disialoganglioside GD2

The anti-idiotype (Id) monoclonal antibody (mAb) 1A7 immunoglobulin G1 (IgG1, kappa), raised in syngeneic mice against the murine anti-ganglioside GD2 mAb 14G2a mimics a carbohydrate epitope on GD2 and serves as a surrogate protein antigen for this disialoganglioside. Immunization of allogeneic C57BL/6 mice and rabbits with 1A7 induced anti-GD2 antibodies of IgG isotype that recognize purified GD2 by enzyme-linked immunosorbent assay (ELISA) and GD2-positive human melanoma cells (M21/P6) by fluorescence-activated cell sorter (FACS) analysis. The specificity of the antisera for GD2 was further confirmed by dot-blot analysis. These antisera also specifically lyse GD2-positive M21/P6 target cells in an antibody-dependent cellular cytotoxicity assay. Taken together, these results suggest that the anti-Id 1A7 can induce GD2-specific IgG antibodies that can recognize cell surface-associated as well as soluble disialoganglioside GD2.

Preclinical evaluation in nonhuman primates of murine monoclonal anti-idiotype antibody that mimics the disialoganglioside GD2

The antiganglioside GD2 monoclonal antibody 14G2a (Ab1) served as an immunogen to generate the anti-idiotype (anti-Id) 1A7 (IgG1,kappa), which mimics GD2 both antigenically and biologically. Anti-Id 1A7 induced anti-GD2 antibodies in mice and rabbits. In this preclinical study, a pair of cynomolgus monkeys, immunized with 1A7 that had been mixed with QS-21 adjuvant, produced anti-anti-Id antibodies (Ab3), which reacted with the GD2-positive melanoma cell line M21/P6 cells but not with GD2-negative LS174-T cells. The Ab3 shared Ids with mAb 14G2a (Ab1), as demonstrated by their ability to inhibit binding of 1A7 to this Ab1. The Ab3 bound specifically to purified GD2 antigen and competed with the Ab1 14G2a in binding to a GD2-positive melanoma cell line or to purified GD2, suggesting that Ab1 and Ab3 may bind to the same epitope and may behave as an Ab1-like antibody (Ab1'). The isotype of the GD2-specific antibodies was mostly IgG in nature. The specificity of the antibodies for GD2 was further confirmed by dot blot analysis. These antisera also specifically lysed GD2-positive target cells in an antibody-dependent cellular cytotoxicity assay. The induction of anti-GD2 responses in monkeys did not cause any apparent side effects, despite the fact that GD2 antigen is expressed by many normal tissues of these animals. Taken together, these results suggest that anti-Id 1A7 can induce GD2-specific antibodies in nonhuman primates and can thus serve as a potential network antigen for triggering active anti-GD2 antibodies in patients with GD2-positive neuroectodermal tumors.

The specificity of the binding site of AchatininH, a sialic acid-binding lectin from Achatina fulica

A sialic acid-binding lectin, AchatininH (ATNH), having unique specificity towards 9-O-acetylneuraminic acid, has been purified and characterized. The specificity of this lectin for O-acetylsialic acids was studied in detail, using various sialic acid derivatives and sialoglycoproteins. The potent inhibition of hemagglutination by bovine submaxillary mucin (BSM), which contains 9(7,8)-O-acetylsialic acid and by free 9-O-acetylneuraminic acid confirms the preferential affinity towards this sugar. Further support for the role of O-acetylsialic acid was obtained by sialidase treatment of BSM. O-Deacetylation of the sialic acid residue abolished its inhibitory potency. Moreover, when the trihydroxypropyl side chain of the sialic acid molecule was modified by periodate-borohydride treatment, the truncated C7-sialic acid was unable to bind ATNH. This result suggests that the glycerol side chain of Neu5Ac, especially the C-8 and/or C-9 portion is an important determinant for ATNH. The hemagglutination-inhibition results using several mono-, di-, and tri-saccharides containing terminal sialic acid and various sialoglycoproteins reveals that ATNH preferentially binds the alpha-(2-->6)-linked sialic acid. Furthermore, beta-D-GlcNAc-(1-->3)-[alpha-NeuGc-(2-->6)]-GalNAc-ol was found to be the best ligand for ATNH.