A molecular basis for MHC class II--associated autoimmunity

Class II major histocompatibility (MHC) molecules have an immunoregulatory role. These cell-surface glycoproteins present fragments of protein antigens (or peptides) to thymus-derived lymphocytes (T cells). Nucleotide sequence polymorphism in the genes that encode the class II MHC products determines the specificity of the immune response and is correlated with the development of autoimmune diseases. This study identifies certain class II polymorphic amino acid residues that are strongly associated with susceptibility to insulin-dependent diabetes mellitus, rheumatoid arthritis, and pemphigus vulgaris. These findings implicate particular class II MHC isotypes in susceptibility to each disease and suggest new prophylactic and therapeutic strategies.

Autoimmune diseases: the failure of self tolerance

The ability to discriminate between self and nonself antigens is vital to the functioning of the immune system as a specific defense against invading microorganisms. Failure of the immune system to "tolerate" self tissues can result in pathological autoimmune states leading to debilitating illness and sometimes death. The induction of autoimmunity involves genetic and environmental factors that have focused the attention of researchers on the trimolecular complex formed by major histocompatibility complex molecules, antigen, and T cell receptors. Detailed molecular characterization of these components points to potential strategies for disease intervention.

Typhoid fever in children aged less than 5 years

BACKGROUND

Calculation of the incidence of typhoid fever during preschool years is important to define the optimum age of immunisation and the choice of vaccines for public-health programmes in developing countries. Hospital-based studies have suggested that children younger than 5 years do not need vaccination against typhoid fever, but this view needs to be re-examined in community-based longitudinal studies. We undertook a prospective follow-up study of residents of a low-income urban area of Delhi, India, with active surveillance for case detection.

METHODS

A baseline census was undertaken in 1995. Between Nov 1, 1995, and Oct 31, 1996, we visited 8172 residents of 1820 households in Kalkaji, Delhi, twice weekly to detect febrile cases. Blood samples were obtained from febrile patients, and those who tested positive for Salmonella typhi were treated with ciprofloxacin.

FINDINGS

63 culture-positive typhoid fever cases were detected. Of these, 28 (44%) were in children aged under 5 years. The incidence rate of typhoid per 1000 person-years was 27.3 at age under 5 years, 11.7 at 5-19 years, and 1.1 between 19 and 40 years. The difference in the incidence of typhoid fever between those under 5 years and those aged 5-19 years (15.6 per 1000 person-years [95% CI 4.7-26.5]), and those aged 19-40 years (26.2 [16.0-36.3]) was significant (p<0.001 for both). The difference between the incidence of typhoid at 5-19 years and the incidence at 19-40 years was also significant (10.6 [6.3-14.8], p<0.001). Morbidity in those under 5 and in older people was similar in terms of duration of fever, signs and symptoms, and need for hospital admission.

INTERPRETATION

Our findings challenge the common view that typhoid fever is a disorder of school-age children and of adults. Typhoid is a common and significant cause of morbidity between 1 and 5 years of age. The optimum age of typhoid immunisation and the choice of vaccines needs to be reassessed.

Zinc supplementation in young children with acute diarrhea in India

BACKGROUND

In developing countries the duration and severity of diarrheal illnesses are greatest among infants and young children with malnutrition and impaired immune status, both factors that may be associated with zinc deficiency. In children with severe zinc deficiency, diarrhea is common and responds quickly to zinc supplementation.

METHODS

To evaluate the effects of daily supplementation with 20 mg of elemental zinc on the duration and severity of acute diarrhea, we conducted a double-blind, randomized, controlled trial involving 937 children, 6 to 35 months of age, in New Delhi, India. All the children also received oral rehydration therapy and vitamin supplements.

RESULTS

Among the children who received zinc supplementation, there was a 23 percent reduction (95 percent confidence interval, 12 percent to 32 percent) in the risk of continued diarrhea. Estimates of the likelihood of recovery according to the day of zinc supplementation revealed a reduction of 7 percent (95 percent confidence interval, -9 percent to +22 percent) in the risk of continued diarrhea during days 1 through 3 and a reduction of 38 percent (95 percent confidence interval, 27 percent to 48 percent) after day 3. When zinc supplementation was initiated within three days of the onset of diarrhea, there was a 39 percent reduction (95 percent confidence interval, 7 percent to 61 percent) in the proportion of episodes lasting more than seven days. In the zinc-supplementation group there was a decrease of 39 percent (95 percent confidence interval, 6 percent to 70 percent) in the mean number of watery stools per day (P = 0.02) and a decrease of 21 percent (95 percent confidence interval, 10 percent to 31 percent) in the number of days with watery diarrhea. The reductions in the duration and severity of diarrhea were greater in children with stunted growth than in those with normal growth.

CONCLUSION

For infants and young children with acute diarrhea, zinc supplementation results in clinically important reductions in the duration and severity of diarrhea.

Zinc supplementation reduces the incidence of acute lower respiratory infections in infants and preschool children: a double-blind, controlled trial

BACKGROUND

Increased acute lower respiratory infection incidence, severity, and mortality are associated with malnutrition, and reduced immunological competence may be a mechanism for this association. Because zinc deficiency results in impaired immunocompetence and zinc supplementation improves immune status, we hypothesized that zinc deficiency is associated with increased incidence and severity of acute lower respiratory infection.

METHODS

We evaluated the effect of daily supplementation with 10 mg of elemental zinc on the incidence and prevalence of acute lower respiratory infection in a double-blind, randomized, controlled trial in 609 children (zinc, n = 298; control, n = 311) 6 to 35 months of age. Supplementation and morbidity surveillance were done for 6 months.

RESULTS

After 120 days of supplementation, the percentage of children with plasma zinc concentrations <60 microg/dL decreased from 35.6% to 11.6% in the zinc group, whereas in the control group it increased from 36.8% to 43.6%. Zinc-supplemented children had 0.19 acute lower respiratory infection episodes/child/year compared with 0.35 episodes/child/year in the control children. After correction for correlation of data using generalized estimating equation regression methods, there was a reduction of 45% (95% confidence interval, 10% to 67%) in the incidence of acute lower respiratory infections in zinc-supplemented children.

CONCLUSIONS

A dietary zinc supplement resulted in a significant reduction in respiratory morbidity in preschool children. These findings suggest that interventions to improve zinc intake will improve the health and survival of children in developing countries.

A newly characterized HLA DQ beta allele associated with pemphigus vulgaris

The inheritance of particular alleles of major histocompatibility complex class II genes increases the risk for various human autoimmune diseases; however, only a small percentage of individuals having an allele associated with susceptibility develop disease. The identification of allelic variants more precisely correlated with disease susceptibility would greatly facilitate clinical screening and diagnosis. Oligonucleotide-primed gene amplification in vitro was used to determine the nucleotide sequence of a class II variant found almost exclusively in patients with the autoimmune skin disease pemphigus vulgaris. In addition to clinical implications, the disease-restricted distribution of this variant should provide insight into the molecular mechanisms underlying associations between diseases and HLA-class II genes.

Profile of 513 patients with alopecia areata: associations of disease subtypes with atopy, autoimmune disease and positive family history

BACKGROUND

Several lines of evidence support a genetic component to alopecia areata (AA), including differences in patients based on severity of AA, associated diseases and family history.

OBJECTIVE

We aimed to examine clinical and genetic features of patients with AA with a focus on associated diseases, especially atopy, and family history of AA in the USA.

METHODS

From 1998 to 2001, 513 patients with AA completed interviews consisting of demographic information, patient's medical history, and family history of AA.

RESULTS

Forty per cent of respondents had alopecia totalis and/or universalis (AT/AU). These patients were younger at the age of onset than those with patchy AA (P < 0.001), were more likely to have associated autoimmune or atopic disease (P = 0.047), most notably atopic dermatitis (P = 0.021) and thyroid disease (P = 0.012). They also had a greater number of relatives affected by AA (P < 0.05).

CONCLUSIONS

Our findings show marked associations between severity of AA, atopic dermatitis, thyroid disease and other autoimmune diseases, and extensive family history of AA, suggesting two clinically distinct subtypes of AA with the severe subtype possibly associated with greater familial autoimmunity. Further research exploring the possibility of a genetic basis to explain these clinical findings will be helpful in clarifying our understanding of AA, leading to improvements in diagnosis and treatment.

Gene expression profile analysis by DNA microarrays: promise and pitfalls

DNA microarrays represent a technological intersection between biology and computers that enables gene expression analysis in human tissues on a genome-wide scale. This application can be expected to prove extremely valuable for the study of the genetic basis of complex diseases. Despite the enormous promise of this revolutionary technology, there are several issues and possible pitfalls that may undermine the authority of the microarray platform. We discuss some of the conceptual, practical, statistical, and logistical issues surrounding the use of microarrays for gene expression profiling. These issues include the imprecise definition of normal in expression comparisons; the cellular and subcellular heterogeneity of the tissues being studied; the difficulty in establishing the statistically valid comparability of arrays; the logistical logjam in analysis, presentation, and archiving of the vast quantities of data generated; and the need for confirmational studies that address the functional relevance of findings. Although several complicated issues must be resolved, the potential payoff remains large.

Phase I and biomarker study of OPB-51602, a novel signal transducer and activator of transcription (STAT) 3 inhibitor, in patients with refractory solid malignancies

BACKGROUND

The aim of this study was to determine the maximum-tolerated dose (MTD), safety, pharmacokinetics, and pharmacodynamics of OPB-51602, an oral, direct signal transduction activator of transcription 3 (STAT3) inhibitor, in patients with refractory solid tumors.

PATIENTS AND METHODS

Three cohorts were studied: cohort A, a sequential dose escalation of OPB-51602 administered intermittently (days 1-14 every 21 days); cohort B, an expansion cohort evaluating the dose lower than the MTD; cohort C, evaluating continuous daily dosing.

RESULTS

Fifty-one patients were studied at 2, 4, and 5 mg per day dosing. The MTD was 5 mg; first-cycle dose-limiting toxicities (DLTs) were grade 3 hyponatremia in one patient, and grade 3 dehydration in another. Intermittent dosing of both 2 and 4 mg doses were tolerable, and the recommended phase II dose was 4 mg. Cohort B investigated 4 mg intermittently, whereas cohort C investigated 4 mg continuously. Common toxicities included fatigue, nausea/vomiting, diarrhea, anorexia, and early-onset peripheral neuropathy. Drug-induced pneumonitis occurred in two patients in cohort C. Continuous dosing was associated with a higher incidence of peripheral neuropathy and a lower mean relative dose intensity, compared with intermittent dosing. Steady-state pharmacokinetics was characterized by high oral clearance, mean elimination half-life ranging from 44 to 61 h, and a large terminal-phase volume of distribution. An active metabolite, OPB-51822, accumulated to a greater extent than OPB-51602. Flow cytometry of peripheral blood mononuclear cells demonstrated pSTAT3 (Tyr(705)) inhibition following exposure. Two patients achieved partial responses at 5 mg intermittently and 4 mg continuously; both had epidermal growth factor receptor (EGFR) mutation-positive non-small-cell lung cancer (NSCLC) with prior EGFR tyrosine kinase inhibitor exposure.

CONCLUSION

OPB-51602 demonstrates promising antitumor activity, particularly in NSCLC. Its long half-life and poorer tolerability of continuous dosing, compared with intermittent dosing, suggest that less frequent dosing should be explored.

CLINICALTRIALSGOV IDENTIFIER

NCT01184807.

Involvement of distinct murine T-cell receptors in the autoimmune encephalitogenic response to nested epitopes of myelin basic protein

The peptide p89-101 (Val-His-Phe-Phe-Lys-Asn-Ile-Val-Thr-Pro-Arg-Thr-Pro) of myelin basic protein is encephalitogenic in mice expressing H-2q and H-2s antigens. Six of 13 encephalitogen-specific T-cell clones were shown to express the variable beta-chain (V beta) 17a gene product (KJ23a+), whereas seven clones were KJ23a-. Both KJ23a+ and KJ23a- subpopulations were encephalitogenic in SJL/J mice when adoptively transferred. Depletion of KJ23a+ cells in vivo with the administration of the antibody KJ23a suppresses experimental allergic encephalomyelitis induced with KJ23a+ T-cell lines. However, experimental allergic encephalomyelitis induced with either (i) encephalitogenic peptide p89-101, (ii) intact myelin basic protein, or (iii) KJ23a- T cells reactive to p89-101 cannot be prevented with monoclonal antibody KJ23a. These data indicate that in spite of the V beta 17a gene expression in a relatively large proportion of p89-101-specific T cells, such V beta gene use is not essential for the induction of experimental allergic encephalomyelitis in SJL/J mice. These results contrast with the predominance of V beta gene use (V beta 8.2) in T cells reactive to the encephalitogenic fragment (pR1-11) in PL/J mice. One reason for this lack of dominant use of a particular T-cell receptor V beta gene family in the autoimmune response to myelin basic protein in SJL/J mice stems from the observation that two encephalitogenic epitopes exist in p89-101. KJ23a- T cells are stimulated by the deleted peptide p89-100, whereas KJ23a+ T cells are not. Thus, in the response to an encephalitogenic fragment of myelin basic protein containing two nested epitopes, at least two distinct T-cell receptor V beta genes are expressed. These distinct T-cell subpopulations can each trigger experimental allergic encephalomyelitis. These findings have implications for therapy of autoimmune disease with antibodies to the T-cell receptor gene products.

Efficacy of zinc supplementation in reducing the incidence and prevalence of acute diarrhea--a community-based, double-blind, controlled trial

A community-based, double-blind, randomized trial was conducted in a population of low socioeconomic status in urban India to determine whether daily zinc supplementation reduces the incidence and prevalence of acute diarrhea, especially in those with zinc deficiency. Children 6-35 mo of age were randomly assigned to zinc (n = 286) and control (n = 293) groups and received a supplement daily for 6 mo. Zinc gluconate (10 mg elemental Zn) was given, with both zinc and control groups also receiving multivitamins. The primary outcome measures determined by home visits every fifth day and physician examinations were the number of acute diarrheal episodes (incidence) and total diarrheal days (prevalence). Zinc supplementation had no effect in children 6-11 mo old. In children aged > 11 mo there was significantly less diarrhea in the zinc group. In boys > 11 mo old, supplementation resulted in a 26% (95% CI: 13%, 38%) lower diarrheal incidence and a 35% (95% CI: 20%, 50%) lower prevalence. In zinc-supplemented girls > 11 mo of age, the incidence was 17% (95% CI: 2%, 30%) lower and the prevalence was 19% (95% CI: 4%, 47%) lower. Overall, zinc supplementation resulted in a 17% (95% CI: 1%, 30%) lower diarrheal incidence in children with plasma zinc concentrations < 9.18 mumol/L at enrollment and a 33% (95% CI: 6%, 52%) lower incidence in children with concentrations < 50 mumol/L. In conclusion, zinc supplementation had a significant effect on acute diarrheal morbidity in children > 11 mo old and in children with low plasma zinc concentrations.

Progressive decline in renal function in diabetic patients with and without albuminuria

This study describes patterns of progression of albuminuria and renal function in a subgroup of 40 patients from a total cohort of 211 diabetic patients (118 type I, 93 type II) followed over a period of 8-14 years. Forty patients (18 with type I diabetes, 22 with type II diabetes) showed progressive increases in albumin excretion rate (AER) and/or decreases in creatinine clearance (CC) during the study period. Of these, AER alone increased in 15 patients, AER increased and CC decreased in 13 patients, and CC alone decreased in 12 patients, with a similar distribution of type I and type II diabetic patients in each group. Of the 28 patients who showed an increase in albuminuria, AER increased at an annual rate of 30-40%, resulting in a 4- to 8-fold increase in AER to > 20 micrograms/min during the study. Of the 25 patients who showed a decrease in renal function, CC decreased at an annual rate of 4-5 ml/min, resulting in an approximate halving of CC to < 90 ml/min during the study. The rate of fall in CC was not related to the presence or absence of concomitant increases in albuminuria. However, a significant preponderance of women in the group showed a decline in CC alone. The decline in CC was associated with an increase in plasma creatinine as well as a progressive decrease in urinary creatinine excretion, but the underlying mechanisms remain unexplained. These data support the concept that a subgroup of diabetic patients may show a decline in renal function in the absence of significant increases in AER.(ABSTRACT TRUNCATED AT 250 WORDS)

Zinc supplementation reduces the incidence of persistent diarrhea and dysentery among low socioeconomic children in India

Persistent diarrhea (PD) and dysentery (DD) account for most diarrhea-associated deaths among children in developing countries. Zinc deficiency can cause stunting and impaired immune function, both of which are risk factors for these diarrheal illnesses. We investigated the effect of zinc supplementation on the incidence of PD and DD in a community-based, double-blind randomized trial in children 6-35 mo of age. Increase over baseline in plasma zinc concentrations in the supplemented group compared with a control group (3.61 vs. 0.009 mumol.L-1), indicated successful supplementation. The overall reductions in the zinc supplemented group of 21% in the incidence of PD (95% CI -6 to 42%) and 14% in the incidence of dysentery (95% CI -15 to 36%) were not significant. There was a significant interaction of treatment effect with baseline plasma zinc concentration and age for PD and with gender for DD. In the zinc-supplemented group compared with the control group, the incidence of PD was reduced by 73% (P < 0.05; 95% CI 34 to 91%) in children with a baseline zinc < 7.65 mumol.L-1 and by 49% (P < 0.05; 95%CI 24 to 66%) in children > 11 mo of age. Zinc supplementation resulted in a 38% (P < 0.05 95%CI 8 to 59%) reduction in the incidence of DD in boys. There was no effect on PD among children 6-11 mo old or on DD in girls. In conclusion, zinc supplementation had a significant impact on the incidence of persistent diarrhea in children > 1 y old and in children with low plasma zinc, as well as on dysentery in boys. These findings may have important implications for reducing diarrhea-related morbidity and mortality.

Preoperative neutrophil to lymphocyte ratio >5 is a prognostic factor for recurrent colorectal cancer

AIM

Previous studies have demonstrated that raised preoperative neutrophil to lymphocyte ratio (NLR) is associated with poor prognosis in colorectal cancer (CRC). The aim of this study was to assess whether preoperative NLR could predict patients at risk of recurrence of CRC.

METHOD

All consecutive patients who underwent surgical resection for CRC over a 2-year period at our institution were analysed. Demographic data including CRC recurrence were prospectively collected from our institutional cancer database. CRC recurrence was diagnosed on radiological and endoscopic histopathological data. Preoperative NLR was calculated on baseline blood results, with a value >5 being a poor prognostic factor. Parametric survival analysis was used to identify risk factors for CRC recurrence. Hazard ratios (HRs) were calculated for gender, CRC stage using Jass score, preoperative NLR and CRC site. P < 0.05 was considered statistically significant.

RESULTS

In all, 297 patients (157 men) underwent CRC resection at a median age of 70 years (range 23-93); 164 patients had colon cancer, 111 rectal cancer and 22 recto-sigmoid cancer. The distribution by stage of CRC was 30.2% for stage 1, 23.8% for stage 2, 19.5% for stage 3 and 26.5% for stage 4. Over a median follow-up period of 3.35 (0.1-8) years, 59 (19.8%) patients had recurrent CRC. Multivariate analysis revealed CRC stage (HR 8.69, 95% CI 3.85-19.6, P < 0.0001) and NLR >5 (HR 1.81, 95% CI 1.07-3.07, P = 0.028) to be significant and independent risk factors predictive of recurrent CRC.

CONCLUSION

These data suggest that preoperative NLR >5 is predictive of CRC recurrence.

Chinese hamster ovary cell mutants defective in glycosaminoglycan assembly and glucuronosyltransferase I

The proteoglycans of animal cells typically contain one or more heparan sulfate or chondroitin sulfate chains. These glycosaminoglycans assemble on a tetrasaccharide primer, -GlcAbeta1, 3Galbeta1,3Galbeta1,4Xylbeta-O-, attached to specific serine residues in the core protein. Studies of Chinese hamster ovary cell mutants defective in the first or second enzymes of the pathway (xylosyltransferase and galactosyltransferase I) show that the assembly of the primer occurs by sequential transfer of single monosaccharide residues from the corresponding high energy nucleotide sugar donor to the non-reducing end of the growing chain. In order to study the other reactions involved in linkage tetrasaccharide assembly, we have devised a powerful selection method based on induced resistance to a mitotoxin composed of basic fibroblast growth factor-saporin. One class of mutants does not incorporate 35SO4 and [6-3H]GlcN into glycosaminoglycan chains. Incubation of these cells with naphthol-beta-D-xyloside (Xylbeta-O-Np) resulted in accumulation of linkage region intermediates containing 1 or 2 mol of galactose (Galbeta1, 4Xylbeta-O-Np and Galbeta1, 3Galbeta1, 4Xylbeta-O-Np) and sialic acid (Siaalpha2,3Galbeta1, 3Galbeta1, 4Xylbeta-O-Np) but not any GlcA-containing oligosaccharides. Extracts of the mutants completely lacked UDP-glucuronic acid:Galbeta1,3Gal-R glucuronosyltransferase (GlcAT-I) activity, as measured by the transfer of GlcA from UDP-GlcA to Galbeta1,3Galbeta-O-naphthalenemethanol (<0.2 versus 3.6 pmol/min/mg). The mutation most likely lies in the structural gene encoding GlcAT-I since transfection of the mutant with a cDNA for GlcAT-I completely restored enzyme activity and glycosaminoglycan synthesis. These findings suggest that a single GlcAT effects the biosynthesis of common linkage region of both heparan sulfate and chondroitin sulfate in Chinese hamster ovary cells.

Purification, characterization and antitumor activity of L-asparaginase isolated from Pseudomonas stutzeri MB-405

An L-asparaginase produced by Pseudomonas stutzeri MB-405 was isolated and characterized. After initial ammonium sulfate fractionation, the enzyme was purified by consecutive column chromatography on Sephadex G-100, Ca-hydroxylapatite, and DEAE-Sephadex A-50. The 665.5-fold purified enzyme thus obtained has the specific activity of 732.3 units mg protein-1 with an overall recovery of 27.2%. The apparent M(r) of the enzyme under nondenaturing and denaturing conditions was 34 kDa and 33 kDa respectively, and the isoelectric point was 6.38 +/- 0.02. It displayed optimum activity at pH 9.0 and 37 degrees C. The enzyme was very specific for L-asparagine and did not hydrolyze L-glutaminate. The Km of the L-asparaginase was found to be 1.45 x 10(-4) M towards L-asparagine and was competitively inhibited by 5-diazo-4-oxo-L- norvaline (DONV) with a Ki of 0.03 mM. Metal ions such as Mn2+, Zn2+, Hg2+, Fe3+, Ni2+, and Cd2+ potentially inhibited the enzyme activity. The activity was enhanced in the presence of thiol-protecting reagents such as DTT, 2-ME, and glutathione (reduced), but inhibited by PCMB and iodoacetamide. The tumor inhibition study with Dalton's lymphoma tumor cells in vivo indicated that this enzyme possesses antitumor properties.

Risk factors predicting desmoid occurrence in patients with familial adenomatous polyposis: a meta-analysis

AIM

Desmoid tumours (DT) are myofibroblastic proliferations occurring in 15% of patients with familial adenomatous polyposis (FAP). Several small series have analysed the incidence of DT and predisposing risk factors. Using meta-analytical techniques, this study aimed to identify risk factors for DT development in patients with FAP.

METHOD

Studies of sporadic DT were excluded. The study end-points were the incidence of DT in FAP and DT development by gender, adenomatous polyposis coli (APC) mutation, family history of DT and previous abdominal surgery. A random effect Mantel-Haenszel model was used to calculate odds ratios for each risk factor and age group.

RESULTS

Ten studies of 4625 patients with FAP fulfilled our inclusion criteria. A total of 559 (12%) patients developed DT. Cumulative analysis demonstrated that 80% of DT developed by age 40, the peak incidence rate being in the second and third decades. A positive family history of DT was the most significant risk factor (OR 7.02, 95% CI 4.15-11.9, P < 0.001). An APC mutation 3' to codon 1399 (OR 4.37, 95% CI 2.14-8.91, P < 0.001) and previous abdominal surgery (OR 3.35, 95% CI 1.33-8.41, P = 0.01) were also implicated. Women were more likely to develop DT (OR 1.57, 95% CI 1.13-2.18, P = 0.007).

CONCLUSION

There is consistency amongst polyposis registries in documenting the incidence and risk factors for DT development. Having a positive family history for DT is of greater significance than a 3' mutation, suggesting the existence of modifier genes, independent of the APC genotype-phenotype correlation. Few of these risk factors are modifiable. Delaying prophylactic surgery could be appropriate in female patients with a 3' APC mutation and attenuated polyposis.

Mutation of the sialyltransferase S-sialylmotif alters the kinetics of the donor and acceptor substrates

Protein sequence analysis of the cloned sialyltransferase gene family has revealed the presence of two conserved protein motifs in the middle of the lumenal catalytic domain, termed L-sialylmotif and S-sialylmotif. In our previous study (Datta, A. K., and Paulson, J. C. (1995) J. Biol. Chem. 270, 1497-1500) the larger L-sialylmotif of ST6Gal I was analyzed by site-directed mutagenesis, which provided evidence that it participates in the binding of the CMP-NeuAc, a common donor substrate for all the sialyltransferases. However, none of the mutants tested in this motif had any significant effect on their binding affinities toward the acceptor substrate asialo alpha1-acid glycoprotein. In this study, we have investigated the role of the S-sialylmotif of the same enzyme ST6Gal I. In total, nine mutants have been constructed by changing the conserved amino acids of this motif to mostly alanine by site-directed mutagenesis. Kinetic analysis for the mutants which retained sialyltransferase activity showed that the mutations in the S-sialylmotif caused a change of Km values for both the donor and the acceptor substrates. Our results indicated that this motif participates in the binding of both the substrates. A sequence homology search also supported this finding, which showed that the downstream amino acid sequence of the S-sialylmotif is conserved for each subgroup of this enzyme family, indicating its association with the acceptor substrate.

Exhaled breath profiles in the monitoring of loss of control and clinical recovery in asthma

BACKGROUND

Asthma is a chronic inflammatory airway disease, associated with episodes of exacerbations. Therapy with inhaled corticosteroids (ICS) targets airway inflammation, which aims to maintain and restore asthma control. Clinical features are only modestly associated with airways inflammation. Therefore, we hypothesized that exhaled volatile metabolites identify longitudinal changes between clinically stable episodes and loss of asthma control.

OBJECTIVES

To determine whether exhaled volatile organic compounds (VOCs) as measured by gas-chromatography/mass-spectrometry (GC/MS) and electronic nose (eNose) technology discriminate between clinically stable and unstable episodes of asthma.

METHODS

Twenty-three patients with (partly) controlled mild to moderate persistent asthma using ICS were included in this prospective steroid withdrawal study. Exhaled metabolites were measured at baseline, during loss of control and after recovery. Standardized sampling of exhaled air was performed, after which samples were analysed by GC/MS and eNose. Univariate analysis of covariance (ANCOVA), followed by multivariate principal component analysis (PCA) was used to reduce data dimensionality. Next paired t tests were utilized to analyse within-subject breath profile differences at the different time-points. Finally, associations between exhaled metabolites and sputum inflammation markers were examined.

RESULTS

Breath profiles by eNose showed 95% (21/22) correct classification for baseline vs loss of control and 86% (19/22) for loss of control vs recovery. Breath profiles using GC/MS showed accuracies of 68% (14/22) and 77% (17/22) for baseline vs loss of control and loss of control vs recovery, respectively. Significant associations between exhaled metabolites captured by GC/MS and sputum eosinophils were found (Pearson r≥.46, P<.01).

CONCLUSIONS & CLINICAL RELEVANCE

Loss of asthma control can be discriminated from clinically stable episodes by longitudinal monitoring of exhaled metabolites measured by GC/MS and particularly eNose. Part of the uncovered biomarkers was associated with sputum eosinophils. These findings provide proof of principle for monitoring and identification of loss of asthma control by breathomics.

Plasminogen activators in human prostate cancer cell lines and tumors: correlation with the aggressive phenotype

The levels of several tumor associated proteases, including plasminogen activators (PA), are elevated in many malignant tumors compared to their benign tumor counterparts. Extracellular matrix degradation mediated by PA may facilitate tumor cell invasion and metastasis. To assess whether PA content correlates with the aggressive phenotype in prostate cancer, we studied these activators in the PC-3 human prostate cell line and PC-3CALN, an aggressive in vivo derived variant cell line. Enzymatic assays using H-D-val-leu-lys-pNA (S-2251) as substrate and peroxidase-anti-peroxidase immunohistochemical techniques were used. In an in vitro chemoinvasion assay, the PC-3CALN variant cell line demonstrated significantly greater invasive behavior than the unselected, parental PC-3 line. The activity of PA secreted by PC-3CALN cells was 3.5 times greater than that of PC-3 cells (p less than 0.01). PC-3 metastases obtained following intrasplenic injection of PC-3 cells had greater PA activities than the corresponding primary tumors. Immunohistochemical studies of PC-3 tumors demonstrated preferential localization of urokinase-type PA to areas of apparent tumor cell invasion. These data suggest a correlation between PA and the aggressive phenotype in this model of human prostate cancer. PA, in particular u-PA, may play a role in the migration and invasion of prostate cancer cells and provide a marker of the aggressive phenotype.

Total synthesis of asimicin and bullatacin

The efficient total synthesis of asimicin, 1, and bullatacin, 2, has demonstrated the advantages of three different strategies for the synthesis of the tricyclic intermediates 6 and 7, which represent the key fragment of the bis-THF Annonaceous acetogenins. The naked carbon skeleton strategy is based on the production of all asymmetric centers by selective placement of the oxygen functions onto an unsaturated, nonfunctionalized carbon skeleton. Diversity in this approach arises from the relative timing of highly stereoselective reactions, such as the Sharpless asymmetric dihydroxylation (AD) reaction, the Kennedy oxidative cyclization (OC) with rhenium(VII) oxide, the Mitsunobu-type alcohol epimerization reaction, and the Williamson etherification reaction. The convergent strategy, which is based on the combinatorial coupling of two series of diastereomeric fragments, to produce intermediates such as 11 and 12, enjoys the advantages of both efficiency and versatility. The third approach, which is based on partially functionalized intermediates, such as 13, combines the advantages of both the linear and the convergent strategies-synthetic efficiency and diversity.

Improving diabetes care in the primary healthcare setting: a randomised cluster trial in remote Indigenous communities

OBJECTIVE

To evaluate a system for improving diabetes care in remote Indigenous communities.

DESIGN

Randomised, unblinded cluster trial over one year (1 March to 29 February 2000).

PARTICIPANTS AND SETTING

Primary healthcare staff in 21 primary healthcare centres in the Torres Strait and Northern Peninsula Area (NPA) Health Service District, north Queensland, and 678 people with diabetes, mostly Torres Strait Islanders.

INTERVENTION

Diabetes recall system established at eight of the 21 sites, as well as staff training in basic diabetes care, regular phone calls from the project officer, a two-monthly newsletter and a mid-project workshop.

MAIN OUTCOME MEASURES

Regular checks of weight, blood pressure, eye and foot care, serum lipid levels and glucose monitoring and control, urinary albumin to creatinine ratio and serum creatinine levels, and administration of recommended vaccines; hospitalisation in the previous 12 months.

RESULTS

There was improvement in most measures at most sites, except for blood pressure monitoring and control, and vaccination status. Intervention sites showed greater improvement in most indicators than control sites (combined relative risk [RR], 1.21; 95% CI, 1.03-1.43). The intervention group showed a 32% reduction in hospital admissions for diabetes-related conditions over the study period (P=0.012). At follow-up, patients in intervention sites were 40% less likely to be hospitalised for a diabetes-related condition than those in control sites (RR, 0.60; 95% CI, 0.41-0.86; P=0.007).

CONCLUSION

A simple recall system, managed by local healthcare workers and supported by a diabetes outreach service, achieved significant improvements in diabetes care and reduced hospitalisations in a high-risk population.

Thyroid hormone receptor gene expression in first trimester human fetal brain

Maternal thyroid hormone is transferred to the fetus early in pregnancy and is postulated to regulate brain development. Thyroid hormone nuclear receptor (TR) proteins are present in fetal brain, but their isoformal composition is unknown. We therefore investigated the ontogeny of TR isoforms and related splice variants in first trimester human fetal brain (n = 9) by semi-quantitative reverse transcriptase-polymerase chain reaction analysis. Expression of the TRbeta1, TRalpha1 and c-erbAalpha2 isoforms was detected from 8.1 weeks gestation (wg). An additional truncated species was detected with the c-erbAalpha2 primer set, consistent with the c-erbAalpha3 splice variant previously described in the rat. All c-erbAalpha-derived transcripts were co-ordinately expressed and increased (ca. 8-fold) between 8.1 and 13.9 wg. A more complex ontogenic pattern was observed for TRbeta1, suggestive of a nadir between 8.4 and 12.0 wg. These findings point to an important role for the TRalpha1 isoform in mediating maternal thyroid hormone action during first trimester human fetal brain development.

The "tamponade test" in the management of massive postpartum hemorrhage

OBJECTIVE

Massive postpartum hemorrhage is a major cause of pregnancy-related death in the United States. To date there is no diagnostic test to identify those women with intractable hemorrhage who will need surgery. Delay in making this decision can be catastrophic. The successful use of the inflated stomach balloon of a Sengstaken-Blakemore tube as a therapy for obstetric hemorrhage has been reported previously. Using the insertion of the Sengstaken-Blakemore tube as a diagnostic test has not been reported. An inflated Sengstaken-Blakemore balloon catheter creates tamponade and identifies those who will or will not need surgery. This is the basis for the "tamponade test." We evaluated the tamponade test in the management of women with massive postpartum hemorrhage.

METHODS

In this prospective study, 16 cases of intractable postpartum hemorrhage were managed by the tamponade test. All 16 women had persistent bleeding despite the maximal and optimal application of conservative measures. Their condition deteriorated, such that surgical intervention was considered mandatory. It was at this predefined end point that the tamponade test was applied.

RESULTS

Fourteen (87.5%) had a positive tamponade test result and therefore did not require surgery. Two (12.5%) had a negative test result and underwent laparotomy.

CONCLUSION

This diagnostic test rapidly identifies those patients with postpartum hemorrhage who will require a laparotomy. Even when results are positive, life-threatening hemorrhage is arrested and time is also allowed to correct any consumptive coagulopathy.