National study on the risks of COVID-19 infection for paediatric kidney transplant recipients: a retrospective, cross-sectional study

INTRODUCTION

During the COVID-19 pandemic, evidence emerged that immunosuppressed children were less affected by COVID-19 infections compared with immunosuppressed adults. The aim of our study was to investigate how COVID-19 infections affected paediatric kidney transplant recipients (pKTR) in the UK.

METHODS

Questionnaires regarding COVID-19 infection data and care of pKTR during the COVID-19 pandemic were sent to all 13 UK paediatric nephrology centres examining asymptomatic and symptomatic pKTR with positive COVID-19 PCR testing from 1 April 2020 to 1 December 2021.

RESULTS

63 pKTR who were 3.1 (range 0.1-15) years post-transplantation had COVID-19 infection with positive SARS-CoV-2 PCR RNA. Classical COVID-19 symptoms were present in half of the patients; with atypical presentations including diarrhoea (13%) and lethargy (13%) also noted, while a third of patients were asymptomatic. Eighteen patients (28%) were hospitalised including five asymptomatic patients admitted for other reasons. No patients needed ventilation or intensive care admission, and one patient received supplemental oxygen. There was evidence of acute kidney injury (AKI) in 71% of patients, but no patients needed kidney replacement therapy with haemofiltration or dialysis.

CONCLUSION

We report 10.4% of the UK paediatric renal transplantation population had documented COVID-19 infections with positive SARS-CoV-2 PCR RNA with 28% of those affected requiring hospitalisation. The increased incidence of AKI, particularly after the first wave of the COVID-19 pandemic, was possibly due to increased testing. There was low morbidity and mortality compared with the adult population.

A33 EFFECTS OF THE NEXT GENERATION PROBIOTIC, AKKERMANSIA MUCINIPHILA, ON INTESTINAL INFLAMMATION AND BARRIER FUNCTION

Background

Inflammatory bowel disease (IBD), characterised by chronic intestinal inflammation, is hypothesised to arise from the interplay between susceptibility genes, the immune system, environmental factors, and gut microbiota. Akkermansia muciniphila is a symbiotic bacterium that accounts for 1-5% of the human fecal microbiota. This microbe has been hailed as a next-generation probiotic, principally with regard to its plethora of beneficial host interactions, including the ability to influence mucin secretion and strengthen the intestinal barrier.

Purpose

Though a clear-cut role and mechanism by which A. muciniphila influences inflammatory conditions is unknown, evidence indicates this microbe is depleted in IBD, suggesting it may have protective effects that are lost in these conditions. Here, we investigate the role and mechanism of A. muciniphila in intestinal inflammation and its influence on intestinal barrier function by utilizing barrier-disrupting models of colitis.

Method

Across several experimental models of intestinal inflammation including the chemically-induced dextran sulphate sodium (DSS) model, the parasitic-based model of Trichuris muris infection, and the spontaneous Muc2-/- model, A.muciniphila was administered by oral gavage. Disease activity index, macroscopic scoring and histological scoring were all performed to assess the severity of intestinal inflammation. Various pro- and anti-inflammatory cytokines were assessed within colonic tissue using commercially available ELISA kits.To investigate the effects that A. muciniphila has on barrier function in the context of colitis, reverse transcriptase qPCR was used to explore several factors, including several TJPs, AMPs, and mucins. To analyse the composition of the microbiota and changes in diversity with A. muciniphila supplementation, 16S rRNA sequencing of fecal samples was performed.

Result(s)

Though only minor benefits were derived from this microbe in germ-free mice, in specific pathogen-free (SPF) mice, administration of pasteurized A. muciniphila in a DSS recovery model ameliorated inflammation severity and promoted recovery compared to controls. When gavaged prior to DSS administration, both live and pasteurized A. muciniphila failed to diminish inflammatory markers indicating minimal preventative effects. T. muris-infected SPF mice treated with live A. muciniphila showed increased levels of Th2 and anti-inflammatory cytokines, decreased worm burden, and enhanced levels of the mucin, Muc5ac, compared with those receiving control broth or pasteurized bacteria. Further, both live and pasteurized A. muciniphila ameliorated the severity of inflammation in a mucin 2 deficient (Muc2^-/-) mouse model of spontaneous colitis, indicating that these protective effects are Muc2-independent.

Conclusion(s)

These observations provide us not only with an enhanced understanding of the role A. muciniphila plays in the pathogenesis of intestinal inflammatory conditions but also may fuel novel avenues of treatment for those with IBD.

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CIHR

Disclosure of Interest

None Declared

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Advanced chronic kidney disease among UK children

The UK Renal Registry currently collects information on UK children with kidney failure requiring long-term kidney replacement therapy (KRT), which supports disease surveillance and auditing of care and outcomes; however, data are limited on children with chronic kidney disease (CKD) not on KRT.

METHODS

In March 2020, all UK Paediatric Nephrology centres submitted data on children aged <16 years with severely reduced kidney function as of December 2019, defined as an estimated glomerular filtration rate <30 mL/min/1.73 m2.

RESULTS

In total, 1031 children had severe CKD, the majority of whom (80.7%) were on KRT. The overall prevalence was 81.2 (95% CI 76.3 to 86.3) per million of the age-related population.

CONCLUSIONS

The prevalence of severe CKD among UK children is largely due to a high proportion of children on long-term KRT. Expanding data capture to include children with CKD before reaching failure will provide greater understanding of the CKD burden in childhood.

Interspecific competition between larval stages of Aedes aegypti and Anopheles stephensi

BACKGROUND & OBJECTIVES

Interspecific competition occurs between members of two or more different species and can often have an influence on mosquito populations. Both Aedes aegypti and Anopheles stepehensi are container breeding mosquitoes and co-exist which may result in larval competition. In this study, interspecific competition between the above two species has been monitored under the laboratory conditions.

METHODS

Three sets of experiments were conducted with different stages of Ae. aegypti and An. stephensi larvae. First two experiments were set up with I/II instar and III/IV instar larvae of Ae. aegypti and An. stephensi respectively in the ratios of 20:20, 20:40 and 40:20 in plastic bowls. For third set of experiment 20 IV instar larvae of Ae. aegypti were put with equal number of I instar larvae of An. stephensi.

RESULTS

In the presence of food, 12.5-15 % mortality was recorded in I/II stage larvae of Ae. aegypti while in An. stephensi mortality ranged from 21-55%. Pupation commenced from Day 6 onwards in Ae. aegypti while in An. stephensi it commenced from Day 11 onwards. In the absence of food, there was no pupation in both the species but Ae. aegypti survived up to longer duration (7.5-18.5 days with 50% mortality) in comparison to An. stephensi (2-7 days with 50% mortality). When younger stages of An. stephensi (I/II) were put together with older stages of Ae. aegypti (III/IV) in the presence of food, pupation was completed in 85% Ae. aegypti population while there was 100% mortality in An. stephensi population.

INTERPRETATION & CONCLUSION

The better survival and development of Ae. aegypti than An. stephensi under the same conditions exhibits interspecies competition showing competitive advantage of Ae. aegypti over An. stephensi. Further research is required to have a thorough understanding of the interaction between these two container inhabiting mosquito species in the nature.

A51 ENTERIC PARASITE INFECTION-INDUCED ALTERATION OF THE GUT MICROBIOTA REGULATES INTESTINAL GOBLET CELL BIOLOGY AND MUCIN PRODUCTION VIA TLR2 SIGNALING

Background

Goblet cells (GCs) are the major source of mucin which are the main components of the mucus layer that represents the front line of innate defense in the gastrointestinal (GI) tract. Hyperplasia of GCs and increased mucin production are observed in many enteric nematode infections such as Trichuris muris infection. Increased mucin production contributes to parasite clearance by trapping in mucus and inhibiting motility. The GI tract contains trillions of commensal microbes, and these microbes control mucin production from GCs by activating different signaling cascades. During nematode parasite infection due to the coexistence of parasites and microbiota in close proximity of GCs in gut, it is likely that this nematode-microbiota interaction plays an important role in mucin production. Toll-like receptors (TLRs), components of the innate immune system, sense gut microbiota stimuli. The human GC-like cell line, LS174T, expresses TLR2 mRNA which was enhanced by stimulation with synthetic TLR2 ligands. We hypothesize T. muris-induced altered microbiota modulates GC response and mucin production via TLR2 signaling.

Aims

To elucidate the role of T. muris-induced altered gut microbiota in the regulation of intestinal GC response and mucin production via host TLR2 signaling.

Methods

C57BL/6 mice were infected by gavage with ~300 T. muris eggs and infectivity was confirmed by worm burden. Microbiota was analyzed by 16s rRNA sequencing. Colonic GCs response, mucins and TLR2 expression and cytokines production were assessed in germ-free (GF) mice receiving non-infected and T. muris-infected microbiota (collected on day 36 post-infection to exclude worms). Muc2 and Muc5ac expression were assessed in wild-type (WT) and TLR2 deficient (TLR2-/-) mice transplanted with T. muris-infected microbiota following antibiotic treatment.

Results

We observed a difference in microbial composition between non-infected and T. muris infected mice. Transfer of T. muris-infected microbiota into GF mice significantly increased GC numbers and TLR2 expression as well as up-regulated Muc2 and Muc5ac expression and IL-4, IL-13 production compared to GF mice with non-infected microbiota. Antibiotic-treated TLR2-/- mice after receiving microbiota from T. muris-infected mice showed significantly decreased expression of Muc2 and Muc5ac compared to antibiotic-treated WT mice receiving the same microbiota.

Conclusions

T. muris-induced altered microbiota influences intestinal GC response and mucin production via TLR2. In addition to enhancing our understanding on the interaction of parasite with resident microbiota in host defense, this study provides new information on TLR2 based innate signaling in the regulation of GC biology and mucin production.

Funding Agencies

NSERC

A219 PROTECTIVE EFFECTS OF AKKERMANSIA MUCINIPHILA ON INTESTINAL BARRIER FUNCTION AND INFLAMMATION

Background

Akkermansia muciniphila, an anaerobic gram-negative bacteria, accounts for ~3% of human gut microbiota. Despite its mucolytic nature, A. muciniphila has been shown to stimulate mucin production, enhance anti-inflammatory regulatory T cell proliferation and improve gut barrier integrity. Interestingly, an inverse relationship has been established between A. muciniphila and several disease states including inflammatory bowel disease (IBD) suggesting it may have protective and anti-inflammatory effects. However, the precise role and mechanism of A. muciniphila in the pathogenesis of colitis remains unknown. Thus, we hypothesize that A. muciniphila may induce protective effects on intestinal inflammation by influencing host immune response and epithelial barrier integrity.

Aims

(1) To investigate the protective role of A. muciniphila in intestinal inflammation in a chemically induced model of IBD and (2) to investigate the protective role of A. muciniphila in intestinal inflammation and host defense in a model of enteric parasitic infection.

Methods

Colitis was induced in germ-free C57BL/6 mice with 2.5% dextran sulphate sodium (DSS) after treatment with either C57BL/6 wild-type (WT) cecal contents or WT cecal contents supplemented with A. muciniphila. Colitis severity was assessed by disease activity index (DAI), macroscopic and histological scores, myeloperoxidase (MPO) assay and cytokine expression. In addition, colitis was induced by Trichuris muris, an intestinal nematode, following treatment with A. muciniphila. Post-infection, the severity of intestinal inflammation was assessed by worm burden, goblet cell staining, cytokines analysis, MPO activity and Muc2 expression. Microbial composition was assessed by 16s rRNA gene sequencing.

Results

In preliminary studies, mice treated with A. muciniphila and administered DSS for 5 days yielded a significant decrease in DAI, macroscopic scoring, and MPO values compared with controls. IL-10 was also elevated in mice receiving A. muciniphila. Groups receiving A. muciniphila in the T. muris model trended toward decreased worm burden, IL-4, IL-13, as well as increased levels of IL-10, goblet cell expression, and Muc2 and Muc5ac expression. A significant decrease in MPO activity was also observed in the group receiving the A. muciniphila-supplemented gavage. Microbial analysis indicated that 3 weeks post-gavage Akkermansia levels were significantly elevated in groups receiving the A. muciniphila-supplemented WT cecal contents versus WT alone. This significance was maintained post-T. muris infection.

Conclusions

These findings suggest that A. muciniphila may have a protective role in the context of intestinal inflammation. This research has the potential to fuel the development of novel treatments by utilizing this protective role in IBD.

Funding Agencies

CIHR

A209 ROLE OF SEROTONIN-AUTOPHAGY AXIS IN REGULATION OF EPITHELIAL CELL FUNCTION AND MICROBIOTA COMPOSITION IN GUT

Background

Serotonin (5-hydroxytryptamine; 5-HT), an enteric signalling molecule mainly produced by the enterochromaffin (EC) cells of the intestinal epithelium regulates various processes of the gut. Tryptophan hydroxylase 1 (Tph1) is the rate-limiting enzyme of 5-HT biosynthesis in EC cells. In inflammatory bowel disease (IBD) and experimental colitis, there are alterations in 5-HT content and microbiota composition in the gut. Previously we reported, Tph1-deficient (Tph1-/-) mice with reduced 5-HT in the gut exhibit reduced susceptibility to colitis. The mechanism by which 5-HT regulates colitis is unknown. Autophagy, a catabolic process regulates the function of intestinal epithelial cells (IECs), gut microbiota, and protects against intestinal inflammation. Both aberrant 5-HT signalling and autophagy is implicated in colitis. It is unclear whether they interact in regulation of production of pro-inflammatory cytokines from IECs and gut microbiota composition in relation to colitis. Our hypothesis is, an increase in 5-HT signalling inhibits autophagy in the IECs, which results in up-regulation of colitis by increasing the production of pro-inflammatory cytokines, and by selection for a more colitogenic microbiota.

Aims

To define the role of 5-HT-autophagy axis in the production of pro-inflammatory cytokines from IECs and gut microbiota composition in intestinal inflammation.

Methods

We investigated level of autophagy with or without 5% dextran sodium sulphate (DSS) in colons, mucosal scraping and IECs of Tph1-/- and their wild-type (WT) littermates. In addition, autophagy and proinflammatory cytokine production were investigated in human colonic epithelial cells (HT-29) following stimulation by 5-HT. We evaluated colitis and gut microbiota composition in WT, Tph1-/-, epithelial-specific autophagy gene Atg7 deficient (Atg7ΔIEC), and Atg7ΔIECTph1-/- (double knock out; DKO) mice.

Results

Tph1 -/- mice, with less 5-HT in the gut than WT mice following DSS administration exhibited an up-regulation of autophagy markers in the colon, mucosal scraping and IECs along with reduction of colitis severity. 5-HT treatment of HT-29 cells resulted in down-regulation of autophagy and upregulation of pro-inflammatory cytokine, IL-8. DKO mice exhibited increased severity of DSS-colitis, and altered microbiota composition compared to Tph1-/- mice.

Conclusions

These findings suggest, an increase in 5-HT in colitis inhibits autophagy in the IECs that contribute to alteration of the gut microbiota and disease severity. Blocking 5-HT signalling may promote autophagy in the IECs and alleviate the severity of colitis. Understanding the contribution of 5-HT in autophagy may identify new therapeutic target in IBD and other intestinal inflammatory conditions that exhibit dysregulated autophagy.

Funding Agencies

CAG, CIHR

TBC1D8B Loss-of-Function Mutations Lead to X-Linked Nephrotic Syndrome via Defective Trafficking Pathways

Steroid-resistant nephrotic syndrome (SRNS) is characterized by high-range proteinuria and most often focal and segmental glomerulosclerosis (FSGS). Identification of mutations in genes causing SRNS has improved our understanding of disease mechanisms and highlighted defects in the podocyte, a highly specialized glomerular epithelial cell, as major factors in disease pathogenesis. By exome sequencing, we identified missense mutations in TBC1D8B in two families with an X-linked early-onset SRNS with FSGS. TBC1D8B is an uncharacterized Rab-GTPase-activating protein likely involved in endocytic and recycling pathways. Immunofluorescence studies revealed TBC1D8B presence in human glomeruli, and affected individual podocytes displayed architectural changes associated with migration defects commonly found in FSGS. In zebrafish we demonstrated that both knockdown and knockout of the unique TBC1D8B ortholog-induced proteinuria and that this phenotype was rescued by human TBC1D8B mRNA injection, but not by either of the two mutated mRNAs. We also showed an interaction between TBC1D8B and Rab11b, a key protein in vesicular recycling in cells. Interestingly, both internalization and recycling processes were dramatically decreased in affected individuals' podocytes and fibroblasts, confirming the crucial role of TBC1D8B in the cellular recycling processes, probably as a Rab11b GTPase-activating protein. Altogether, these results confirmed that pathogenic variations in TBC1D8B are involved in X-linked podocytopathy and points to alterations in recycling processes as a mechanism of SRNS.

Treatment of diffuse systemic sclerosis with hyperimmune caprine serum (AIMSPRO): a phase II double-blind placebo-controlled trial

Objective

The primary objective of the study was to explore safety and tolerability of hyperimmune caprine serum (AIMSPRO) in established diffuse cutaneous systemic sclerosis (SSc). Secondary objectives included assessment of potential efficacy and biological activity and exploration of candidate biomarkers.

Methods

This was a double-blind parallel group randomised placebo-controlled clinical trial. After informed consent 20 patients with established diffuse cutaneous SSc of greater than 3 years duration not receiving immunosuppressive therapy were randomised to receive either active (n=10) or placebo formulation (n=10) by subcutaneous twice weekly injection over 26 weeks. Clinical assessments were evaluated over 26 weeks.

Results

There were no safety concerns during this study. Frequency of adverse events was not different between active and placebo groups. Mean modified Rodnan Skin Score (mRSS) fell by 1.4±4.7 units with active treatment but increased by 2.1±6.4 units on placebo when baseline values were compared with 26 weeks and responder analysis showed clinically meaningful improvement in mRSS at 26 weeks in 5 (50%) of actively treated patients compared with 1 (10%) in the control group (p=0.062). PIIINP (µg/L) showed a comparatively larger increase in the treatment group compared with the placebo group, (p=0.0118).

Conclusions

These results confirm tolerability and safety of this novel biological agent in established diffuse SSc. The value of a placebo treated control group in small clinical trials evaluating skin disease in SSc is confirmed. Potential improvement in mRSS and changes in PIIINP in cases receiving active therapy suggest that this intervention may be of clinical benefit and warrants further evaluation.

Review of the bioenvironmental methods for malaria control with special reference to the use of larvivorous fishes and composite fish culture in central Gujarat, India

Mosquito control with the use of insecticides is faced with the challenges of insecticide resistance in disease vectors, community refusal, their high cost, operational difficulties, and environmental concern. In view of this, integrated vector control strategies with the use of larvivorous fishes such as Guppy (Poecilia reticulata) and Gambusia (G. affinis) as biological control agents were used in controlling mosquito breeding in different types of breeding places such as intradomestic containers, various types of wells, rice-fields, pools, ponds and elsewhere in malaria prone rural areas of central Gujarat. Attempts were also made to demonstrate composite fish culture in unused abandoned village ponds by culturing Guppy along with the food fishes such as Rohu (Labeo rohita), Catla (Catla catla) and Mrigal (Cirrhinus mrigala). Income generated from these ponds through sale of fishes was utilized for mosquito control and village development. The technology was later adopted by the villagers themselves and food fish culture was practised in 23 ponds which generated an income of Rs 1,02,50,992 between 1985 and 2008. The number of villages increased from 13 to 23 in 2008 and there was also gradual increase of income from Rs 3,66,245 in 1985-90 to Rs 55,06,127 in 2002-08 block. It is concluded that larvivorous fishes can be useful tool in controlling mosquito breeding in certain situations and their use along with composite fish culture may also generate income to make the programme self-sustainable.

Bionomics and vectorial capacity of Anopheles annularis with special reference to India: a review

Anopheles annularis is widely distributed mosquito species all over the country. An. annularis has been incriminated as a malaria vector in India, Sri Lanka, Bangladesh, Myanmar, Indonesia, Malaysia and China. In India, it has been reported to play an important role in malaria transmission as a secondary vector in certain parts of Assam, West Bengal and U.P. In Odisha and some neighbouring countries such as Sri Lanka, Nepal and Myanmar it has been recognised as a primary vector of malaria. This is a species complex of two sibling species A and B but the role of these sibling species in malaria transmission is not clearly known. An. annularis is resistant to DDT and dieldrin/HCH and susceptible to malathion and synthetic pyrethorides in most of the parts of India. In view of rapid change in ecological conditions, further studies are required on the bionomics of An. annularis and its role in malaria transmission in other parts of the country. Considering the importance of An. annularis as a malaria vector, the bionomics and its role in malaria transmission has been reviewed in this paper. In this communication, an attempt has been made to review its bionomics and its role as malaria vector. An. annularis is a competent vector of malaria, thus, due attention should be paid for its control under the vector control programmes specially in border states where it is playing a primary role in malaria transmission.

The structure and crystallization of thin water films on Pt(111)

When water is adsorbed on Pt(111) above 135 K several different ice structures crystallize, depending on the thickness of the ice layer. At low coverage water forms extended islands of ice with a (square root(37) x square root(37))R25(o) unit cell, which compresses as the monolayer saturates to form a (square root(39) x square root(39))R16(o) structure. The square root(39) low-energy electron diffraction (LEED) pattern becomes more intense as the second layer grows, remaining bright for films up of 10-15 layers and then fading and disappearing for films more than ca. 40 layers thick. The ice multilayer consists of an ordered square root(39) wetting layer, on which ice grows as a crystalline film which progressively loses its registry to the wetting layer. Ice films more than ca. 50 layers thick develop a hexagonal LEED pattern, the entire film and wetting layer reorienting to form an incommensurate bulk ice. These changes are reflected in the vibrational spectra which show changes in line shape and intensity associated with the different ice structures. Thin amorphous solid water films crystallize to form the same phases observed during growth, implying that these structures are thermodynamically stable and not kinetic phases formed during growth. The change from a square root(39) registry to incommensurate bulk ice at ca. 50 layers is associated with a change in crystallization kinetics from nucleation at the Pt(111) interface in thin films to nucleation of incommensurate bulk ice in amorphous solid water films more than 50 layers thick.

The structure of the mixed OH+H2O overlayer on Pt{111}

The structure of the mixed p(3 x 3)-(3OH + 3H2O) phase on Pt[111] has been investigated by low-energy electron diffraction-IV structure analysis. The OH + H2O overlayer consists of hexagonal rings of coplanar oxygen atoms interlinked by hydrogen bonds. Lateral shifts of the O atoms away from atop sites result in different O-O separations and hexagons with only large separations (2.81 and 3.02 angstroms) linked by hexagons with alternating separations of 2.49 and 2.813.02 angstroms. This unusual pattern is consistent with a hydrogen-bonded network in which water is adsorbed in cyclic rings separated by OH in a p(3 x 3) structure. The top-most two layers of the Pt atoms relax inwards with respect to the clean surface and both show vertical buckling of up to 0.06 angstroms. In addition, significant shifts away from the lateral bulk positions have been found for the second layer of Pt atoms.

Field evaluation of biolarvicides in Surat city, India

BACKGROUND & OBJECTIVES

Two bacterial larvicide (bio-larvicide) formulations--Bacticide and VectoBac containing viable endospores and delta endotoxin of Bacillus thuringiensis var israelensis H-14 were evaluated in 2001 for their mosquito larvicidal efficacy under the operational conditions of urban malaria control programme in Surat city, India.

METHODS

Larvicides were applied at the recommended dose in selected breeding habitats of Anopheles (An. stephensi), Aedes (Ae. aegypti) and Culex (Cx. quinquefasciatus) and reductions in the densities of III and IV instars were compared with that of untreated matched controls.

RESULTS

At the construction sites in cemented tanks/chambers VectoBac produced reduction in the density of III and IV instar larvae of An. stephensi (98-100%) and Ae. aegypti (100%) in the first week of application whereas Bacticide produced 71-100% reduction in An. stephensi and 100% in Ae. aegypti. Re-application of VectoBac on Day 10 caused better control up to Day 20 when compared with Bacticide. In stagnant water pools, VectoBac produced 27.6-85.3% reduction in the larvae of An. subpictus and 18.5-83.8% in those of Cx. quinquefasciatus whereas Bacticide produced 23.3-30.3% and 39-97.2% reduction in An. subpictus and Cx. quinquefasciatus larval densities in the first week post application, respectively. Bacticide application gave better impact on Cx. quinquefasciatus larvae in the second week after re-application as compared to VectoBac. In storm water drains, VectoBac caused respectively 6.2-100% and 6.4-97.6% reduction in An. subpictus and Cx. quinquefasciatus larvae in the first week of application whereas Bacticide produced 100% and 13.3-98.8% reduction in An. subpictus and Cx. quinquefasciatus larval densities, respectively.

INTERPRETATION & CONCLUSION

Both the formulations were equally effective on An. subpictus and Cx. quinquefasciatus larvae after a second application. The results showed that application of these biolarvicides would be required at 7-10 day intervals. The health workers engaged in the application of biolarvicides reported a better ease of handling and application of the liquid formulation (VectoBac) than the wettable powder formulation (Bacticide).

Hydrogen bonding in mixed OH+H2O overlayers on Pt(111)

The stability of OH on Pt(111) has been investigated to determine the role of hydrogen bonding in stabilizing the overlayer. We find that the optimal structure is a mixed (OH+H2O) phase, confirming recent density-functional theory predictions. The reaction O+3H(2)O forms a hexagonal (sqrt[3]xsqrt[3])R30 degrees -(OH+H2O) lattice with a weak (3x3) superstructure, caused by ordering of the hydrogen bonds. The mixed overlayer can accommodate a range of H(2)O/OH compositions but becomes less stable as the H2O content is reduced, causing defects in the hydrogen-bonding network that lift the (3 x 3) superstructure and destabilize the overlayer.

Skull base involvement by a nasopharyngeal carcinoma shown by Tc-99m MDP SPECT but not by computed tomography

PURPOSE

Plain radiographs, computed tomography (CT), and more recently magnetic resonance imaging (MRI) are used routinely to stage carcinoma of the nasopharynx. Tc-99m methylene diphosphonate (MDP) SPECT is seldom used for local staging of the disease.

MATERIALS AND METHODS

Plain radiographs and CT were used to stage squamous carcinoma of the nasopharynx in a 50-year-old man with a left XII nerve palsy.

RESULTS

Findings of the plain radiographs were normal, whereas the CT scan revealed a nonhomogenous hyperdense mass in the nasopharynx but intact underlying bone. Given the symptoms, a Tc-99m MDP planar scan was ordered and showed no enhanced uptake, but SPECT images obtained at the same time revealed markedly increased focal radiotracer uptake in the region of the tumor, indicating osseous involvement.

CONCLUSION

Possible bony invasion with a nasopharyngeal carcinoma may be better shown with MDP SPECT than with planar isotope bone scans, plain radiographs, or CT.

Differential activation of signal transduction pathways in human hearts with hypertrophy versus advanced heart failure

BACKGROUND

Left ventricular failure is commonly preceded by a period of hypertrophy. Intriguingly, many of the signaling pathways that have been implicated in the regulation of hypertrophy, including the 3 mitogen-activated protein kinases (MAPKs: extracellular signal-regulated kinase, stress-activated protein kinase, and p38), protein phosphatase, calcineurin, and the protein kinase Akt and its target glycogen synthase kinase-3 (GSK-3), also regulate the apoptotic response.

METHODS AND RESULTS

To understand the mechanisms that might regulate the progression of heart failure, we analyzed the activity of these signaling pathways in the hearts of patients with advanced heart failure, patients with compensated cardiac hypertrophy, and normal subjects. In patients with hypertrophy, neither the MAPK nor the Akt/GSK-3 pathways were activated, and the dominant signaling pathway was calcineurin. In failing hearts, calcineurin activity was increased but less so than in the hypertrophied hearts, and all 3 MAPKs and Akt were activated (and, accordingly, GSK-3ss was inhibited), irrespective of whether the underlying diagnosis was ischemic or idiopathic cardiomyopathy.

CONCLUSIONS

In the failing heart, there is a clear prohypertrophic activity profile, likely occurring in response to increased systolic wall stress and neurohormonal mediators. However, with the activation of these hypertrophic pathways, potent proapoptotic and antiapoptotic signals may also be generated. Therapies directed at altering the balance of activity of these signaling pathways could potentially alter the progression of heart failure.

Glycogen synthase kinase-3beta is a negative regulator of cardiomyocyte hypertrophy

Hypertrophy is a basic cellular response to a variety of stressors and growth factors, and has been best characterized in myocytes. Pathologic hypertrophy of cardiac myocytes leads to heart failure, a major cause of death and disability in the developed world. Several cytosolic signaling pathways have been identified that transduce prohypertrophic signals, but to date, little work has focused on signaling pathways that might negatively regulate hypertrophy. Herein, we report that glycogen synthase kinase-3beta (GSK-3beta), a protein kinase previously implicated in processes as diverse as development and tumorigenesis, is inactivated by hypertrophic stimuli via a phosphoinositide 3-kinase-dependent protein kinase that phosphorylates GSK-3beta on ser 9. Using adenovirus-mediated gene transfer of GSK-3beta containing a ser 9 to alanine mutation, which prevents inactivation by hypertrophic stimuli, we demonstrate that inactivation of GSK-3beta is required for cardiomyocytes to undergo hypertrophy. Furthermore, our data suggest that GSK-3beta regulates the hypertrophic response, at least in part, by modulating the nuclear/cytoplasmic partitioning of a member of the nuclear factor of activated T cells family of transcription factors. The identification of GSK-3beta as a transducer of antihypertrophic signals suggests that novel therapeutic strategies to treat hypertrophic diseases of the heart could be designed that target components of the GSK-3 pathway.

Calcineurin promotes protein kinase C and c-Jun NH2-terminal kinase activation in the heart. Cross-talk between cardiac hypertrophic signaling pathways

Multiple intracellular signaling pathways have been shown to regulate the hypertrophic growth of cardiomyocytes. Both necessary and sufficient roles have been described for the mitogen activated protein kinase(1) (MAPK) signaling pathway, specific protein kinase C (PKC) isoforms, and calcineurin. Here we investigate the interdependence between calcineurin, MAPK, and PKC isoforms in regulating cardiomyocyte hypertrophy using three separate approaches. Hearts from hypertrophic calcineurin transgenic mice were characterized for PKC and MAPK activation. Transgenic hearts demonstrated activation of c-Jun NH(2)-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK1/2), but not p38 MAPK factors. Calcineurin transgenic hearts demonstrated increased activation of PKCalpha, beta(1), and theta, but not of epsilon, beta(2), or lambda. In a second approach, cultured cardiomyocytes were infected with a calcineurin adenovirus to induce hypertrophy and the effects of pharmacologic inhibitors or co-infection with a dominant negative adenovirus were examined. Calcineurin-mediated hypertrophy was prevented with PKC inhibitors, Ca(2+) chelation, and attenuated with a dominant negative SEK-1 (MKK4) adenovirus, but inhibitors of ERK or p38 activation had no effect. In a third approach, we examined the activation of MAPK factors and PKC isoforms during the progression of load-induced hypertrophy in aortic banded rats with or without cyclosporine. We determined that inhibition of calcineurin activity with cyclosporine prevented PKCalpha, theta, and JNK activation, but did not affect PKCepsilon, beta, lambda, ERK1/2, or p38 activation. Collectively, these data indicate that calcineurin hypertrophic signaling is interconnected with PKCalpha, theta, and JNK in the heart, while PKCepsilon, beta, lambda, p38, and ERK1/2 are not involved in calcineurin-mediated hypertrophy.

Regulation of cardiac hypertrophy in vivo by the stress-activated protein kinases/c-Jun NH(2)-terminal kinases

Cardiac hypertrophy often presages the development of heart failure. Numerous cytosolic signaling pathways have been implicated in the hypertrophic response in cardiomyocytes in culture, but their roles in the hypertrophic response to physiologically relevant stimuli in vivo is unclear. We previously reported that adenovirus-mediated gene transfer of SEK-1(KR), a dominant inhibitory mutant of the immediate upstream activator of the stress-activated protein kinases (SAPKs), abrogates the hypertrophic response of neonatal rat cardiomyocytes to endothelin-1 in culture. We now report that gene transfer of SEK-1(KR) to the adult rat heart blocks SAPK activation by pressure overload, demonstrating that the activity of cytosolic signaling pathways can be inhibited by gene transfer of loss-of-function mutants in vivo. Furthermore, gene transfer of SEK-1(KR) inhibited pressure overload-induced cardiac hypertrophy, as determined by echocardiography and several postmortem measures including left ventricular (LV) wall thickness, the ratio of LV weight to body weight, cardiomyocyte diameter, and inhibition of atrial natriuretic factor expression. Our data suggest that the SAPKs are critical regulators of cardiac hypertrophy in vivo, and therefore may serve as novel drug targets in the treatment of hypertrophy and heart failure.

Effect of subcutaneous injection of granulocyte-macrophage colony stimulating factor (GM-CSF) on healing of chronic refractory wounds

OBJECTIVE

To assess the effect of granulocyte macrophage colony-stimulating factor (GM-CSF) on healing of chronic wounds.

DESIGN

Prospective open study.

SETTING

1 cancer hospital and 2 University hospitals, Pakistan.

SUBJECTS

35 patients with chronic wounds (duration 3 months or longer) that had not responded to standard treatment. Patients with malignant ulcers were excluded.

INTERVENTION

GM-CSF 10 microg/cm2 was injected subcutaneously along the edges and base of the wound. The treatment was given only once and patients were followed weekly for a minimum of six weeks.

MAIN OUTCOME MEASURES

Changes in size, shape, depth, edges and base of the wound, amount and quality of the granulation tissue, and type of discharge.

RESULTS

Six patients were excluded from the analysis, 4 who died early of underlying disease and were not evaluable, and 2 who were excluded when histological examination of the wound showed that it was malignant. Although various types of wounds were studied, most (n = 10, 34%) were postoperative. 23 of the wounds were over 2 cm in diameter (mean 4.8 x 4.6 cm) with thin granulation tissue, and almost half were infected. Nine of the 29 wounds healed completely within six weeks while another 11 decreased in size by more than 50%; 7 patients responded slightly. Only two wounds showed no evidence of healing during the observation period. More than half of the 20 wounds that responded had healed by three weeks. Response did not correlate with any clinical variable including the presence of infection. Toxicity was negligible.

CONCLUSIONS

We conclude that subcutaneous injection of a single dose of GM-CSF may induce healing in refractory chronic wounds. Trials are necessary to validate these initial observations and to decide the optimal dose and route, and whether any additional benefit may be derived from repeated injections.

Perinatal exposure to morphine disrupts brain norepinephrine, ovarian cyclicity, and sexual receptivity in rats

The effect of perinatal exposure to morphine on the development of catecholaminergic and reproductive function in female rats was investigated. Adult rats received morphine intraperitoneally daily for 40 days. The dose of morphine was progressively increased at 10-day intervals from 5, 7.5, 10 to 15 mg/kg body weight until day 40. The rats were mated between days 38 and 45. Administration of morphine at dose rates of 20 and 30 mg/kg continued during pregnancy. The dose was increased to 40 mg/kg for 10 days postpartum. Results showed that morphine disrupted ovarian cyclicity in 52% of the females. Amongst the remaining females, 43% became pregnant when mated. In the female offspring born to such dams, sexual maturation was delayed and body weight was reduced until weaning. At adulthood, lordosis behavior was inhibited when the female offspring were tested against stimulus males. Plasma estradiol and ovarian estradiol and progesterone levels were reduced. Norepinephrine concentration in the hypothalamus was reduced, whereas it remained unchanged in the amygdala. Dopamine concentrations in both hypothalamus and amygdala were not influenced by perinatal morphine exposure. These results suggest that chronic morphine treatment during perinatal life selectively influences the development of noradrenergic mechanisms in the rat brain and this may in turn be responsible for reduced reproductive activity.

A double-blind, placebo-controlled, randomized trial to evaluate the role of tetrachlorodecaoxide in the management of chemotherapy-induced oral mucositis

We conducted a double-blind, placebo-controlled, randomized trial to evaluate the efficacy and safety of tetrachlorodecaoxide (TCDO) in patients with chemotherapy-induced mucositis. Sixty-two patients with World Health Organization grade II-IV oral mucositis were eligible for the study. They were randomized to receive TCDO or placebo, 10 ml, twice daily, swish and swallow, for 7 days. Patients were evaluated for oral pain, dysphagia, and oral intake. Downgrading and total duration of mucositis were documented. Thirty-two were randomized to receive TCDO. Thirty received the placebo. All were evaluable. Both arms were well matched for age, gender, type of underlying neoplasm, and prior history of oral mucositis. Intensity of initial symptoms, degree of mucositis, and time period between delivery of chemotherapy and development of mucositis were also similar. Post-therapy evaluation revealed no significant difference in the mean grade of oral and esophageal pain, or dysphagia between TCDO and placebo. Downgrading or total duration of mucositis did not differ between the two groups. Oral intake improved significantly in patients taking TCDO. Time to subjective improvement in oral pain was significantly shorter with TCDO (3.1 versus 3.6 days). Evaluation on day 3 revealed that 77% of those receiving TCDO were free of oral pain in comparison to 46% receiving placebo (P = 0.05). These results indicate that TCDO may be helpful in palliating some of the symptoms related to oral mucositis. The therapeutic benefit, however, is small and needs to be confirmed in a larger trial.

A prospective phase II trial to evaluate the efficacy and toxicity of hepatic arterial infusion of ifosfamide in patients with inoperable localized hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common tumor in the developing countries. Most patients present with relatively advanced disease and have a poor survival. Due to lack of any effective therapy, there is an urgent need to investigate new drugs. We conducted a prospective trial to evaluate the efficacy and tolerability of ifosfamide (IFEX) in patients with histologically proved, inoperable, localized HCC. Eligibility criteria included World Health Organization (WHO) performance status (PS) of 0-2, bilirubin < or = 3.0 mg/dl, albumin > or = 2.5 g/dl, creatinine < or = 2.0 mg/dl, correctable coagulation profile, adequate bone marrow function, and no prior therapy. Hepatic arterial infusion of IFEX (6 g/m2) was given continuously over 96 hours. Mesna was given intravenously, in same doses, throughout IFEX infusion and for 12 hours afterwards. Nineteen patients were enrolled in the trial. Mean age was 51.1 years and all were men. Most of the patients had PS 1. The majority had viral hepatitis and cirrhosis. Eleven had raised serum alpha fetoprotein (AFP) levels. Thirteen patients had multiple lesions involving both lobes of the liver. Mean size of ultrasonographically evident largest lesion was 11.0 cm. Three patients are inevaluable; one died early, one refused further therapy, and another was lost to follow-up. Among the 16 evaluable patients, 6 (37.5%) had partial remission and 4 (25%) had a minor response. An additional four (25%) patients had stable disease. Only two (12.5%) patients had progression of disease while on therapy. Overall response rate (partial plus minor) was 62.5%. Mean duration of partial response was 5.0 months and mean survival was 7.1 months. Subjective improvement in pain was observed in all but two patients and correlated well with the objective response. Chemotherapy-related side effects were predominantly grade III-IV anemia and alopecia. Three patients had catheter-related complications (one local infection, one bleeding, and one thrombosis). Two patients developed mild encephalopathy and two had hepatic decompensation as evidenced by worsening liver function tests. The results of this pilot study suggest that IFEX, given as a continuous hepatic arterial infusion, is an active drug in inoperable localized HCC. Toxicity is manageable. This drug deserves further trials to properly evaluate its therapeutic potential.