SETD2 mutations do not contribute to clonal fitness in response to chemotherapy in childhood B cell acute lymphoblastic leukemia

Mutations in genes encoding epigenetic regulators are commonly observed at relapse in B cell acute lymphoblastic leukemia (B-ALL). Loss-of-function mutations in SETD2, an H3K36 methyltransferase, have been observed in B-ALL and other cancers. Previous studies on mutated SETD2 in solid tumors and acute myelogenous leukemia support a role in promoting resistance to DNA damaging agents. We did not observe chemoresistance, an impaired DNA damage response, nor increased mutation frequency in response to thiopurines using CRISPR-mediated knockout in wild-type B-ALL cell lines. Likewise, restoration of SETD2 in cell lines with hemizygous mutations did not increase sensitivity. SETD2 mutations affected the chromatin landscape and transcriptional output that was unique to each cell line. Collectively our data does not support a role for SETD2 mutations in driving clonal evolution and relapse in B-ALL, which is consistent with the lack of enrichment of SETD2 mutations at relapse in most studies.

NSD2 E1099K drives relapse in pediatric acute lymphoblastic leukemia by disrupting 3D chromatin organization

BACKGROUND

The NSD2 p.E1099K (EK) mutation is shown to be enriched in patients with relapsed acute lymphoblastic leukemia (ALL), indicating a role in clonal evolution and drug resistance.

RESULTS

To uncover 3D chromatin architecture-related mechanisms underlying drug resistance, we perform Hi-C on three B-ALL cell lines heterozygous for NSD2 EK. The NSD2 mutation leads to widespread remodeling of the 3D genome, most dramatically in terms of compartment changes with a strong bias towards A compartment shifts. Systematic integration of the Hi-C data with previously published ATAC-seq, RNA-seq, and ChIP-seq data show an expansion in H3K36me2 and a shrinkage in H3K27me3 within A compartments as well as increased gene expression and chromatin accessibility. These results suggest that NSD2 EK plays a prominent role in chromatin decompaction through enrichment of H3K36me2. In contrast, we identify few changes in intra-topologically associating domain activity. While compartment changes vary across cell lines, a common core of decompacting loci are shared, driving the expression of genes/pathways previously implicated in drug resistance. We further perform RNA sequencing on a cohort of matched diagnosis/relapse ALL patients harboring the relapse-specific NSD2 EK mutation. Changes in patient gene expression upon relapse significantly correlate with core compartment changes, further implicating the role of NSD2 EK in genome decompaction.

CONCLUSIONS

In spite of cell-context-dependent changes mediated by EK, there appears to be a shared transcriptional program dependent on compartment shifts which could explain phenotypic differences across EK cell lines. This core program is an attractive target for therapeutic intervention.

Oncogenic deubiquitination controls tyrosine kinase signaling and therapy response in acute lymphoblastic leukemia

Dysregulation of kinase signaling pathways favors tumor cell survival and therapy resistance in cancer. Here, we reveal a posttranslational regulation of kinase signaling and nuclear receptor activity via deubiquitination in T cell acute lymphoblastic leukemia (T-ALL). We observed that the ubiquitin-specific protease 11 (USP11) is highly expressed and associates with poor prognosis in T-ALL. USP11 ablation inhibits leukemia progression in vivo, sparing normal hematopoiesis. USP11 forms a complex with USP7 to deubiquitinate the oncogenic lymphocyte cell-specific protein-tyrosine kinase (LCK) and enhance its activity. Impairment of LCK activity leads to increased glucocorticoid receptor (GR) expression and glucocorticoids sensitivity. Genetic knockout of USP7 improved the antileukemic efficacy of glucocorticoids in vivo. The transcriptional activation of GR target genes is orchestrated by the deubiquitinase activity and mediated via an increase in enhancer-promoter interaction intensity. Our data unveil how dysregulated deubiquitination controls leukemia survival and drug resistance, suggesting previously unidentified therapeutic combinations toward targeting leukemia.

Altered BAF occupancy and transcription factor dynamics in PBAF-deficient melanoma

ARID2 is the most recurrently mutated SWI/SNF complex member in melanoma; however, its tumor-suppressive mechanisms in the context of the chromatin landscape remain to be elucidated. Here, we model ARID2 deficiency in melanoma cells, which results in defective PBAF complex assembly with a concomitant genomic redistribution of the BAF complex. Upon ARID2 depletion, a subset of PBAF and shared BAF-PBAF-occupied regions displays diminished chromatin accessibility and associated gene expression, while BAF-occupied enhancers gain chromatin accessibility and expression of genes linked to the process of invasion. As a function of altered accessibility, the genomic occupancy of melanoma-relevant transcription factors is affected and significantly correlates with the observed transcriptional changes. We further demonstrate that ARID2-deficient cells acquire the ability to colonize distal organs in multiple animal models. Taken together, our results reveal a role for ARID2 in mediating BAF and PBAF subcomplex chromatin dynamics with consequences for melanoma metastasis.

Utility of serum Galactomannan in diagnosing COVID-19 patients with suspected IPA: an observational study in resource limited settings

OBJECTIVE

To study the utility of Galactomannan (GM) antigen as a screening marker for diagnosing invasive pulmonary aspergillosis (IPA) in coronavirus disease 2019 (COVID-19) patients.

PATIENTS AND METHODS

The serum samples from patients with severe COVID-19 diseases admitted to the Critical Care Unit were collected on the 5th day of admission for GM screening. The samples were analysed by enzyme linked immune sorbent assay (ELISA) and GM index of more than 1 was considered as positive. All GM positive patients were serially followed until discharge or death.

RESULTS

The GM was raised in serum of 12 out of 38 patients, indicating an incidence of possible COVID-19 associated IPA (CAPA) in 31.57% of patients. The median age of these CAPA patients was 56.5 years, males were significantly more affected than females. The inflammatory marker serum ferritin was raised in all 12 patients (median value of 713.74 ng/ml), while IL-6 was raised in 9 patients (median value of 54.13 ng/ml). None of these patients received antifungals. Their median length of hospital stay was 20 days (IQR: 12, 34 days). All these patients succumbed to the illness.

CONCLUSIONS

The serum GM appears to be sensitive diagnostic tool to identify early IPA in COVID-19 patients and pre-emptive antifungal therapy could play a role in salvaging these patients.

P61 Impact of the COVID-19 pandemic on the presentation and management of acute appendicitis: a single-centre analysis

Introduction

The COVID-19 pandemic has influenced the delivery of healthcare. In accordance with the UK Joint Royal Colleges’ advice the management of acute appendicitis (AA) changed with greater consideration for non-operative management (NOM) or open appendicectomy where operative management (OM) s sought. Our aim is to share our experience of the presentation, management and outcomes for patients presenting to our Trust with AA to guide care for future viral pandemics.

Methods

This single-centre retrospective cohort study included patients diagnosed with AA in March to July 2019 compared with March to July 2020. Medical records were used to evaluate demographics, inflammatory markers, imaging, severity, management, histology, length of stay (LOS), complications and 90-day outcomes.

Results

There were 149 and 125 patients in the 2019 and 2020 cohort, respectively. 14 patients (9.4%) had NOM in 2019 versus 31 patients (24.8%) in 2020 (p = 0.001). In the 2019 OM group 125 patients (92.6%) had laparoscopic appendicectomy versus 69 (73.4%) in 2020. 59 patients (39.6%) had a CT in 2019 versus 70 (56%) in 2020. The median LOS was 4 days (interquartile range (IQR) 3 to 6 days) in 2019 and 3 days (IQR 2 to 5 days) in 2020 (p = 0.03). Two patients in each year who received NOM had treatment failure (14.3% in 2019 and 6.5% in 2020). Three patients in 2019 who had OM had treatment failure (2.2%). Of 95 patients tested for COVID-19 all but one was negative.

Conclusion

During the COVID-19 pandemic there was no observed increase in severity of AA, patients had a shorter LOS and were more likely to have imaging. NOM proportionally increased with no observed change in outcomes.

Surface antigen-guided CRISPR screens identify regulators of myeloid leukemia differentiation

Lack of cellular differentiation is a hallmark of many human cancers, including acute myeloid leukemia (AML). Strategies to overcome such a differentiation blockade are an approach for treating AML. To identify targets for differentiation-based therapies, we applied an integrated cell surface-based CRISPR platform to assess genes involved in maintaining the undifferentiated state of leukemia cells. Here we identify the RNA-binding protein ZFP36L2 as a critical regulator of AML maintenance and differentiation. Mechanistically, ZFP36L2 interacts with the 3' untranslated region of key myeloid maturation genes, including the ZFP36 paralogs, to promote their mRNA degradation and suppress terminal myeloid cell differentiation. Genetic inhibition of ZFP36L2 restores the mRNA stability of these targeted transcripts and ultimately triggers myeloid differentiation in leukemia cells. Epigenome profiling of several individuals with primary AML revealed enhancer modules near ZFP36L2 that associated with distinct AML cell states, establishing a coordinated epigenetic and post-transcriptional mechanism that shapes leukemic differentiation.

Anaemia in patients with type 2 diabetes mellitus without nephropathy is related to iron deficiency

BACKGROUND AND AIMS

Iron deficiency anaemia, although well reported in diabetic nephropathy, has not been well studied in type 2 diabetes patients in the absence of nephropathy. We studied the prevalence of anaemia and iron deficiency in type 2 diabetes patients without nephropathy.

MATERIAL AND METHODS

A total of 89 patients were selected for this study. 24 h urine protein less than 500 mg was used as the criteria to rule out diabetic nephropathy. Complete hemogram, iron profile and high sensitivity C reactive protein (hs CRP) levels were performed in each patient.Functional iron deficiency (FID) was defined as serum ferritin more than 100 μg/l with serum transferrin less than 20% and total iron deficiency state was defined as serum ferritin less than 100 μg/l.

RESULTS

Fifteen patients (16.8%)had anaemia out of which 13 had total iron deficiency and one each had functional iron deficiency and normal iron status respectively. Assessment of the iron status overall showed that 49 patients had TID (55.05%), 16 had FID (17.9%)and 24 (27.05%) had normal iron status. The hs-CRP was significantly higher in those with iron deficiency.

CONCLUSIONS

The present study found a high prevalence of iron deficiency anaemia in type 2 diabetic patients even in the absence of nephropathy. Most of the diabetic subjects also displayed an iron deficiency state the cause of which needs further investigation.

Evolution of the Epigenetic Landscape in Childhood B Acute Lymphoblastic Leukemia and Its Role in Drug Resistance

Although B-cell acute lymphoblastic leukemia (B-ALL) is the most common malignancy in children and while highly curable, it remains a leading cause of cancer-related mortality. The outgrowth of tumor subclones carrying mutations in genes responsible for resistance to therapy has led to a Darwinian model of clonal selection. Previous work has indicated that alterations in the epigenome might contribute to clonal selection, yet the extent to which the chromatin state is altered under the selective pressures of therapy is unknown. To address this, we performed chromatin immunoprecipitation, gene expression analysis, and enhanced reduced representation bisulfite sequencing on a cohort of paired diagnosis and relapse samples from individual patients who all but one relapsed within 36 months of initial diagnosis. The chromatin state at diagnosis varied widely among patients, while the majority of peaks remained stable between diagnosis and relapse. Yet a significant fraction was either lost or newly gained, with some patients showing few differences and others showing massive changes of the epigenetic state. Evolution of the epigenome was associated with pathways previously linked to therapy resistance as well as novel candidate pathways through alterations in pyrimidine biosynthesis and downregulation of polycomb repressive complex 2 targets. Three novel, relapse-specific superenhancers were shared by a majority of patients including one associated with S100A8, the top upregulated gene seen at relapse in childhood B-ALL. Overall, our results support a role of the epigenome in clonal evolution and uncover new candidate pathways associated with relapse. SIGNIFICANCE: This study suggests a major role for epigenetic mechanisms in driving clonal evolution in B-ALL and identifies novel pathways associated with drug resistance.

Abstract 5399: The NSD2 p.E1099K mutation is enriched at relapse and confers drug resistance in a cell context dependent manner in pediatric acute lymphoblastic leukemia

Introduction: Outcomes for children with relapsed acute lymphoblastic leukemia (ALL) remain poor. Mutations in epigenetic modifiers are commonly found at relapse, including the activating p.E1099K (EK) mutation within the conserved SET domain of NSD2, which has been reported in 10% of patients at relapse. NSD2 has 3 isoforms, two of which (Types II and REIIBP) contain the SET domain. Our aim was to determine the role of NSD2 in driving relapse and further elucidate the prevalence of NSD2 EK in patient samples.

Methods: Whole genome/exome sequencing was performed on diagnosis/relapse ALL pairs and data were aggregated for somatic SNVs/indels. NSD2 EK positive cases at relapse were subject to ultra-deep targeted re-sequencing to determine the presence of small subclones at diagnosis. To investigate the role of NSD2 and its isoforms in mediating relapse, short hairpin RNAs (shRNAs) were used to knockdown (KD) NSD2 in three NSD2 EK mutant cell lines with non-targeting (NT) shRNA used as controls. Cells were treated with chemotherapy commonly used in pediatric ALL and assessed for cytotoxicity by CellTiter- Glo®. To determine NSD2's impact on gene expression and the epigenetic landscape, RNAseq, ChIPseq, ATACseq, and Hi-C were performed using standard techniques.

Results: Examination of paired ALL patient samples revealed enrichment of NSD2 EK clones at relapse. B-ALL cell lines heterozygous for NSD2 EK (RS4;11, RCH-ACV, SEM) revealed that KD led to decreased proliferation in all lines and decreased clonal growth in RCH-ACV relative to NT. Furthermore, increased sensitivity to various chemotherapeutic agents was observed in the KD lines compared to NT controls, but the pattern of drug sensitivity varied among lines implying cell context specific drug responses. Simultaneous knockdown of Type II and REIIBP had a greater impact than Type II alone, indicating both SET containing EK isoforms contribute to phenotypic changes. When comparing gene expression changes in NT vs KD, minimal overlap in differential genes was noted among the three cell lines (4.4% upregulated, 1.7% downregulated) indicating significant diversity in transcriptional reprogramming. ATACseq of the NT and KD for all three lines revealed intergenic regions as the most affected by NSD2 with RCH-ACV and RS4;11 NT lines having more open chromatin compared to their KD whereas SEM NT displayed marked peak loss compared to its KD. Less than 2% of differential intergenic regions were shared among the lines. Hi-C analysis demonstrated disparity in chromosome architecture among NSD2 EK lines as well. Shifts in intergenic regions was further supported by ChIPseq, which revealed increased H3K36me2 across intergenic regions in RS4;11 NT compared to KD. Lastly, we noted a strong correlation of increased gene expression with increased H3K36me2, H3K9ac, and H3K27ac at promoters and gene bodies.

Conclusions: NSD2 EK plays a unique role in mediating clonal fitness through pleiotropic mechanisms that are dependent on the underlying cellular context.

Citation Format: Joanna Pierro, Jason Saliba, Sonali Narang, Gunjan Sethia, Shella Saint Fleur-Lominy, Ashfiyah Chowdhury, Takaya Moriyama, Kjeld Schmiegelow, Jun J. Yang, Mignon L. Loh, Patrick A. Brown, Jinghui Zhang, Xiaotu Ma, Aristotelis Tsirigos, Nikki A. Evensen, William L. Carroll. The NSD2 p.E1099K mutation is enriched at relapse and confers drug resistance in a cell context dependent manner in pediatric acute lymphoblastic leukemia [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5399.

Feasibility of monitoring peripheral blood to detect emerging clones in children with acute lymphoblastic leukemia†

Relapse-enriched somatic variants drive drug resistance in childhood acute lymphoblastic leukemia. We used digital droplet-based polymerase chain reaction to establish whether relapse-enriched mutations in emerging subclones could be detected in peripheral blood samples before frank relapse. Although limitations in sensitivity for some probes hindered detection of certain variants, we successfully detected variants in NT5C2 and PRPS1 at a fractional abundance of 0.005% to 0.3%, 41 to 116 days before relapse. As mutations in both these genes confer resistance to thiopurines, early detection protocols using peripheral blood could be implemented to preemptively alter maintenance therapy to extinguish resistant clones before overt relapse.

The NSD2 p.E1099K Mutation Is Enriched at Relapse and Confers Drug Resistance in a Cell Context-Dependent Manner in Pediatric Acute Lymphoblastic Leukemia

The NSD2 p.E1099K (EK) mutation is observed in 10% of acute lymphoblastic leukemia (ALL) samples with enrichment at relapse indicating a role in clonal evolution and drug resistance. To discover mechanisms that mediate clonal expansion, we engineered B-precursor ALL (B-ALL) cell lines (Reh, 697) to overexpress wildtype (WT) and EK NSD2, but observed no differences in proliferation, clonal growth, or chemosensitivity. To address whether NSD2 EK acts collaboratively with other pathways, we used short hairpin RNAs to knockdown expression of NSD2 in B-ALL cell lines heterozygous for NSD2 EK (RS4;11, RCH-ACV, SEM). Knockdown resulted in decreased proliferation in all lines, decreased clonal growth in RCH-ACV, and increased sensitivity to cytotoxic chemotherapeutic agents, although the pattern of drug sensitivity varied among cell lines implying that the oncogenic properties of NSD2 mutations are likely cell context specific and rely on cooperative pathways. Knockdown of both Type II and REIIBP EK isoforms had a greater impact than knockdown of Type II alone, suggesting that both SET containing EK isoforms contribute to phenotypic changes driving relapse. Furthermore, in vivo models using both cell lines and patient samples revealed dramatically enhanced proliferation of NSD2 EK compared with WT and reduced sensitivity to 6-mercaptopurine in the relapse sample relative to diagnosis. Finally, EK-mediated changes in chromatin state and transcriptional output differed dramatically among cell lines further supporting a cell context-specific role of NSD2 EK. These results demonstrate a unique role of NSD2 EK in mediating clonal fitness through pleiotropic mechanisms dependent on the genetic and epigenetic landscape. IMPLICATIONS: NSD2 EK mutation leads to drug resistance and a clonal advantage in childhood B-ALL.

Mutations associated with human neural tube defects display disrupted planar cell polarity in Drosophila

Planar cell polarity (PCP) and neural tube defects (NTDs) are linked, with a subset of NTD patients found to harbor mutations in PCP genes, but there is limited data on whether these mutations disrupt PCP signaling in vivo. The core PCP gene Van Gogh (Vang), Vangl1/2 in mammals, is the most specific for PCP. We thus addressed potential causality of NTD-associated Vangl1/2 mutations, from either mouse or human patients, in Drosophila allowing intricate analysis of the PCP pathway. Introducing the respective mammalian mutations into Drosophila Vang revealed defective phenotypic and functional behaviors, with changes to Vang localization, post-translational modification, and mechanistic function, such as its ability to interact with PCP effectors. Our findings provide mechanistic insight into how different mammalian mutations contribute to developmental disorders and strengthen the link between PCP and NTD. Importantly, analyses of the human mutations revealed that each is a causative factor for the associated NTD.

A Deep Learning Framework for Predicting Response to Therapy in Cancer

A major challenge in cancer treatment is predicting clinical response to anti-cancer drugs on a personalized basis. Using a pharmacogenomics database of 1,001 cancer cell lines, we trained deep neural networks for prediction of drug response and assessed their performance on multiple clinical cohorts. We demonstrate that deep neural networks outperform the current state in machine learning frameworks. We provide a proof of concept for the use of deep neural network-based frameworks to aid precision oncology strategies.

Targeting Mitochondrial Structure Sensitizes Acute Myeloid Leukemia to Venetoclax Treatment

The BCL2 family plays important roles in acute myeloid leukemia (AML). Venetoclax, a selective BCL2 inhibitor, has received FDA approval for the treatment of AML. However, drug resistance ensues after prolonged treatment, highlighting the need for a greater understanding of the underlying mechanisms. Using a genome-wide CRISPR/Cas9 screen in human AML, we identified genes whose inactivation sensitizes AML blasts to venetoclax. Genes involved in mitochondrial organization and function were significantly depleted throughout our screen, including the mitochondrial chaperonin CLPB. We demonstrated that CLPB is upregulated in human AML, it is further induced upon acquisition of venetoclax resistance, and its ablation sensitizes AML to venetoclax. Mechanistically, CLPB maintains the mitochondrial cristae structure via its interaction with the cristae-shaping protein OPA1, whereas its loss promotes apoptosis by inducing cristae remodeling and mitochondrial stress responses. Overall, our data suggest that targeting mitochondrial architecture may provide a promising approach to circumvent venetoclax resistance. SIGNIFICANCE: A genome-wide CRISPR/Cas9 screen reveals genes involved in mitochondrial biological processes participate in the acquisition of venetoclax resistance. Loss of the mitochondrial protein CLPB leads to structural and functional defects of mitochondria, hence sensitizing AML cells to apoptosis. Targeting CLPB synergizes with venetoclax and the venetoclax/azacitidine combination in AML in a p53-independent manner.See related commentary by Savona and Rathmell, p. 831.This article is highlighted in the In This Issue feature, p. 813.

ABC analysis of anti cancer drugs in a tertiary care Employees’ State Insurance Corporation Hospital in Delhi

Background: Material management is co-ordinated activities comprising of planning, acquiring, storing and controlling the supply of various items for optimal use. Effective inventory management can bring about a substantial decrease in expenditure. ABC analysis categorizes all items based on their annual drug expenditure into three categories A, B and C for better control by different level managers.Methods: ABC analysis for anticancer drugs was done in ESIC Hospital, Basaidarapur which is a tertiary care hospital of ESI Corporation in Delhi. Total number of drugs analysed were 98 with total annual expenditure of Rupees 5.77 crores approximately.Results: 12.2% (n=12), 16.3% (n=16) and 71.4% (n=70) items were found to be in A, B and C categories respectively.Conclusions: ABC analysis identified the drugs which need more strict control by top level management. Inventory control techniques should be an integral part of any hospital store.

Atorvastatin in clinically-significant macular edema in diabetics with a normal lipid profile

INTRODUCTION

Lipid-lowering drugs preserve vision and reduce the risk of hard exudates in clinically-significant macular edema(CSME) in diabetics with an abnormal lipid profile. But their role in reducing CSME in diabetics with a normal lipid profile is not yet known.

OBJECTIVE

To evaluate the role of atorvastatin in CSME in diabetics with a normal lipid profile.

MATERIALS AND METHODS

A prospective, randomized clinical trial was carried out. Thirty CSME patients with a normal lipid profile were randomly divided into Group A and B. Atorvastatin had been started in Group A four weeks prior to laser treatment. The main outcome measures were any improvement or deterioration in visual acuity and macular edema and hard exudates at six months follow-up.

STATISTICS

Both the groups were compared using unpaired t test for quantitative parameters and chi-square test for qualitative parameters. A p value of less than 0.05 was taken as significant.

RESULTS

Visual acuity, macular edema and hard exudates resolution was not significantly different in the two groups (P = 0.14, 0.62, 0.39 respectively).

CONCLUSION

Atorvastatin does not affect treatment outcome in CSME with a normal lipid profile over a short term follow-up.

Probable Vogt-Koyanagi-Harada's syndrome associated with tonic pupils

BACKGROUND

Pupillary abnormalities with complete or incomplete form of VKH have rarely been reported. We report a case of "probable" Vogt- Koyanagi-Haradas (VKH) disease associated with tonic pupils.

CASE

A young healthy male presented with 15 days' history of bilateral decrease in vision. The patient had bilateral panuveitis with exudative retinal detachment associated with tonic pupils. There were no other systemic associations. The ultrasonography and fluorescein angiography findings were consistent with VKH disease.

CONCLUSION

Pupillary reaction abnormalities though uncommon could be seen in association with "probable" VKH disease.

Microbial contamination in open globe injury

INTRODUCTION

Endophthalmitis is the most dreaded complication of ocular trauma and knowledge of the microbial contaminants is essential to start empirical antibiotic therapy.

PURPOSE

To determine incidence of contamination after open globe injuries (OGI) in our setup and to identify the spectrum of microorganisms contaminating open globe injuries.

MATERIAL AND METHODS

A prospective study including 50 consecutive eyes of open globe injury over a period of two years was conducted. Intra-operatively, 4 - 5 samples were taken from the inferior conjunctival sac and anterior chamber at the beginning and end of the open globe injury repair. Any abscised tissue or foreign body was also sent for culture sensitivity. A vitreous tap was taken from eyes with posterior segment trauma with signs of endophthalmitis.

RESULTS

Microbial cultures were positive in13 eyes (26 %). The microbial spectrum included Aspergillus species in 45.6 %, Alternaria in 15.2 %, Curvularia in 15.2 %, Staphylococcus aureus in 7.6 %, Bacillus species in 7.6 %, and Streptococcus pneumoniae in 7.6 %. Of these 13 eyes, nine eyes developed clinically evident frank endophthalmitis during follow-up. Overall, endophthalmitis developed in 20 eyes (40 %). There was a significant association between the initial contamination and development of endophthalmitis (p less than 0.05). 53 % of culture positive cases achieved ambulatory vision compared to 73 % of culture-negative cases.

CONCLUSION

Initial contamination was seen in 26 % of OGI cases. Aspergillus (fungus) was the commonest contaminant. There was a strong correlation between the initial contamination and development of endophthalmitis. Culture-negative cases had a trend towards better final visual outcome than culture-positive cases. Close follow up of cases showing contamination following OGI is recommended.

Evaluation of the efficacy of magnesium sulphate as an adjuvant to lignocaine for intravenous regional anaesthesia for upper limb surgery

Several additives have been combined with local anaesthetics for intravenous regional anaesthesia to improve block quality, analgesia and to decrease tourniquet pain. Magnesium sulphate is one potential additive. This prospective, randomised, double-blinded study was conducted in 30 ASA physical status I or II patients undergoing upper limb surgery under tourniquet. In group L, patients received intravenous regional anaesthesia with lignocaine alone (9 ml of 2% lignocaine diluted with normal saline to total volume of 36 ml). Patients in group M received intravenous regional anaesthesia with lignocaine plus magnesium sulphate (6 ml of 25% magnesium sulphate plus 9 ml of 2% lignocaine diluted with normal saline to total volume of 36 ml). Assessment was by observing the response to injection of drug; sensory and motor block and tourniquet pain. The mean time of onset of sensory block was 12.40 and 3.47 minutes in groups L and M respectively (P < 0.001). The average times of onset of motor block in groups L and M were 17 and six minutes respectively (P < 0.001). Of the patients in group M, 66.7% reported moderate to severe pain while the drug was being injected, compared to 20% in group L (P=0.011). There was a statistically significant difference in visual analogue scale for tourniquet pain at 10 and 30 minutes after tourniquet inflation (lower in group M). These findings indicate that magnesium sulphate added as an adjuvant to lignocaine hastens the onset of sensory and motor block and decreases tourniquet pain. However there is increased incidence of transient pain on injection if magnesium sulphate is added.

Chronic diarrhoea in HIV patients: prevalence of coccidian parasites

The purpose of this study was to determine the prevalence of intestinal parasites in HIV patients with or without diarrhoea and to see an association between diarrhoea and the coccidian parasites in our setting. Stool samples from 113 HIV patients, 34 chronic diarrhoea and 79 without any history of diarrhoea were collected and examined for enteric parasites by microscopy. One hundred and thirteen control samples from HIV negative patients complaining of prolonged diarrhoea were also collected and analysed. Prevalence of coccidian parasites in HIV and non-HIV patients; with and without diarrhoea was compared using chi-square tests. Enteric parasites were detected in 55.8% HIV patients with diarrhoea compared to 16.4% in patients without diarrhoea (P<0.001). Isospora belli was found in 41.1% (14/34) of chronic diarrhoea and 6.3% (5/79) in non-diarrhoeal cases (P<0.001). Cryptosporidium was detected in 20.6% (7/34) of chronic diarrhoea and 2.5% (2/79) in non-diarrhoeal cases (P<0.001). Cyclospora cayetanensis associated diarrhoea was detected in only one case of chronic diarrhoea (2.9%). CD4+ T-cell count was lower (180 cells/microL) in diarrhoeal HIV patients as compared to non-diarrhoeal patients. Coccidian parasites were seen at a mean CD4+ T-cell count of 186.3 cells/microL. This study concluded that Isospora belli was the predominant parasite followed by Cryptosporidium spp. and both were strongly associated with diarrhoea among HIV patients.

Cardiotoxic Manifestations of Yellow Oleander (Thevetia nerifolia) Poisoning and its Treatment: A Case Report

A 30-year-'old female came to the hospital with complaints of vomiting, drowsiness and bradycardia after ingesting five seeds of yellow oleander (Thevetia nerifolia - pila kaner) with the intent of committing suicide. Whereas the usual complication is hyperkalemia, she was suffering from hypokalemia. She responded to conventional treatment, consisting of atropine and correction of electrolytes. This report discusses the cardiotoxic and neurotoxic manifestations of yellow oleander poisoning, its early diagnosis and prompt treatment. We would like to emphasize the importance of taking an electrocardiogram in all cases of poisoning.

Optimization of xylanase production by Melanocarpus albomyces IIS68 in solid state fermentation using response surface methodology

Xylanase production by the thermophilic fungus, Melanocarpus albomyces IIS68, during solid state fermentation of wheat straw was studied and the effects of various variables were observed. Using the response surface methodology and the multivariant statistical approach, the optimum levels of the variables affecting xylanase production were determined. The optimum levels of the variables were 600-850 microm particle size, 43 h inoculum age, 1.37% Tween 80, 86% initial moisture content, 5.1% urea, 0.74% yeast extract and a harvest time of 96 h. Under these optimized conditions, xylanase activity of 7760 U/g initial dry substrate was obtained which was in very good agreement with the value predicted by the quadratic model (7890 U/g initial dry substrate).

Frequency doubled Nd:YAG (532 nm) laser photocoagulation in corneal vascularisation: efficacy and time sequenced changes

PURPOSE

To evaluate the efficacy of frequency-doubled Nd:YAG (532 nm) laser treatment in quiescent corneal vascularisation, and to record the sequential changes in lasered vessels and complications in eyes with one and two quadrant vascularisation.

METHODS

Thirty eyes (30 patients)--15 eyes (15 patients) with one-quadrant and 15 eyes (15 patients) with two-quadrant corneal vascularisation were treated. Frequency-doubled Nd:YAG laser (532 nm) was used at laser setting of 120-480 mw power, 50-150 mm spot size and 0.05 sec pulse duration. The area of corneal vascularisation, status of treated corneal vessels, area of corneal opacity and visual acuity were recorded before treatment, at one week after treatment and thereafter at monthly intervals up to three months.

RESULTS

The mean area of corneal vascularisation decreased from 20.09% to 8.31% of the total corneal area in group I (p<0.01) and from 44.34% to 20.67% of the total corneal area in group II (p<0.01) at 3 months' follow-up. The mean reduction in the area of corneal vascularisation was 58.64% in group I and 53.38% in group II (p>0.05). Of 148 corneal vessels treated, 60 (44.6%) were totally occluded, 44 (30%) partially occluded, 37 (28%) recanalized and there was one shunt vessel at one week following laser treatment. At three months' follow-up, 80 (54.15%) vessels were totally occluded, 14 (9%) partially occluded, 52 (35.14%) recanalised and two shunt vessels appeared. Thus, at three months' follow-up, the number of totally occluded vessels increased and partially occluded vessels decreased. Superficial corneal haemorrhage was observed in 4 (14%) patients.

CONCLUSION

Frequency-doubled Nd:YAG (532 nm) laser photocoagulation appears a safe and effective means of reducing the area of corneal vascularisation in quiescent eyes with vascularised corneal opacities.

Fungal endophthalmitis following cataract surgery: clinical presentation, microbiological spectrum, and outcome

PURPOSE

To determine the clinical presentation, microbiological spectrum, and outcome in cases of fungal endophthalmitis following cataract surgery.

DESIGN

Observational case series.

METHODS

SETTING

Tertiary referral hospital.

PATIENTS

Retrospective analysis of 27 cases of smear- and culture-proven fungal endophthalmitis.

INTERVENTION

Pars plana vitrectomy in 18 eyes, where the corneal condition did not preclude the same. All eyes received intravitreal amphotericin B and dexamethasone along with systemic antifungal agents.

MAIN OUTCOME MEASURES

Functional success: Final visual acuity of 3/60 or better with attached retina. Anatomical success: Final visual acuity of better than light perception with preserved anatomy of globe.

RESULTS

The majority of the eyes (22 of the 27) had early onset and diffuse presentation (that is, anterior segment as well as posterior vitreous exudates). Substantial corneal involvement was seen in 14 eyes (51.85%). Aspergillus sp. was the most common isolate. Multivariate analysis using forward stepwise logistic regression showed corneal involvement as the single most important risk factor in determining final visual outcome (P =.0429).

CONCLUSIONS

Early onset and diffuse presentation, which mimics bacterial endophthalmitis, stresses the importance of both bacterial and fungal cultures from intraocular fluids to reach a diagnosis apart from the clinical judgment. Corneal involvement was the most important predictor of outcome in cases of fungal endophthalmitis.

Phakonit: phacoemulsification through a 0.9 mm corneal incision

Advances in technique and equipment have led to a significant increase in the popularity of phacoemulsification and have increased its safety and efficiency. We describe a technique, phakonit, in which the lens is emulsified through a 0.9 mm clear corneal temporal incision. A cortical wash with bimanual irrigation/aspiration is followed by enlarging the incision to 2.0 mm and inserting a Staar sub-2.0 mm foldable intraocular lens. Phakonit is a safe, precise method of phacoemulsification with minimal intraoperative or postoperative complications.

Lingual cysticercosis--a case report

Cysticercosis is unlikely to be the first diagnosis for a swelling over the tongue. In this report we document an unusual case of lingual cysticercosis presenting as an isolated lesion.

Anesthesia for patients with a mediastinal mass

Anesthesia for patients with mediastinal masses carries a significant risk for fatal or near-fatal cardiorespiratory events. Careful history taking and thorough preoperative investigation, including CT, identify most susceptible patients. Preoperative fiberoptic bronchoscopy performed by or involving the anesthesiologist is invaluable for determining the plan for intubation and ventilation. A coordinated approach involving anesthesiologists and surgeons is essential.

Efficacy of various laser wavelengths in the treatment of clinically significant macular edema in diabetics

BACKGROUND AND OBJECTIVE

To compare various laser wavelengths: argon green (514 nm), vs krypton red (647 nm), vs frequency doubled Nd:YAG (532 nm), and vs diode (810 nm), for laser photocoagulation treatment in clinically significant macular edema (CSME) in diabetics.

PATIENTS AND METHODS

Four different wavelengths were used to sequentially treat 271 eyes of 164 diabetic patients with CSME. Follow up was conducted for a minimum of 6 months (9.8 +/- 1.3 months). Retreatment was performed if residual edema involving the foveal avascular zone persisted at 3 months.

RESULTS

Reduction/elimination of CSME was observed in 93.3% of argon-treated eyes, 88.5% in krypton red group, 92.9% with frequency doubled Nd:YAG, and 84.8% with diode laser with no statistically significant difference between the groups (P > 0.05 for all groups). The number of eyes requiring retreatment was highest with the diode laser having 44.3% of eyes requiring retreatment and least with frequency doubled Nd:YAG having only 15.5% of eyes requiring retreatment (P = 0.0002).

CONCLUSIONS

All lasers are equally effective in reducing/eliminating CSME. However, Nd:YAG may have an advantage because of requiring fewer retreatments.

Threshold retinopathy of prematurity: ocular changes and sequelae following cryotherapy

PURPOSE

To determine ocular changes and sequelae following cryotherapy for threshold retinopathy of prematurity (ROP).

METHODS

This is a retrospective study of 49 eyes of 26 premature babies with threshold ROP treated with cryotherapy between 1995 and 1998. All eyes included in the study had favourable structural outcome after cryotherapy. Follow-up examination of all babies was done 12 - 62 months (average 28 months) after cryotherapy. Visual axis, fixation pattern, anterior segment examination, cycloplegic refraction and dilated fundus examination with indirect ophthalmoscopy were undertaken in all eyes during follow-up.

RESULTS

Posterior pole retinal residuae observed following cryotherapy were tortousity of blood vessels in 32 (65.3%), narrow temporal arcade in 22 (44.89%), temporal crescent in 17 (34.69%), disc drag in 13 (26.53%) and macular heterotopia in 7 (14.28%) eyes. Myopia was observed in 20 (40.82%) eyes and strabismus in 5 (19.23%) babies. The significant risk factor for ocular changes was ROP with more clock hours of involvement (p < 0.05). Higher period of gestation was associated with posterior pole changes (p< 0.05).

CONCLUSIONS

All premature babies with threshold ROP treated with cryotherapy require frequent and long-term follow up to look for retinal residuae, refractive status, and ocular motility disorders.

Traumatic lens abscess with chornic endophthalmitis successfully treated with pars plana lensectomy and vitrectomy

Intralenticular abscess is a rare entity and has been infrequently reported after surgery, metastatic infection, or trauma. We report a case of post traumatic lens abscess with low-grade endophthalmitis following a penetrating eye injury with a splinter of wood. The patient was successfully treated with a pars plana lensectomy and vitrectomy. Despite thorough microbiological investigations, no causative organism could be isolated.