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.

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.

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.

Engineering Sialic Acid Synthesis Ability in Insect Cells

Insect cells lack the ability to synthesize the sialic acid donor molecule CMP-sialic acid or its precursor, sialic acid. In this chapter, we describe a method to engineer CMP-sialic acid synthesis capability into Spodoptera frugiperda (Sf9) cells, a prototypical insect cell line, by recombinant expression of sialic acid synthesis pathway genes using baculovirus technology. Co-expression of a sialuria mutant UDP-GlcNAc-2-epimerase/ManNAc kinase (EKR263L), wild-type sialic acid 9-phosphate synthase (SAS), and wild-type CMP-sialic acid synthetase (CSAS) in the presence of GlcNAc leads to synthesis of CMP-sialic acids synthesis to support sialylation of N-glycans on glycoproteins.

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.

A mathematical model to derive N-glycan structures and cellular enzyme activities from mass spectrometric data

Effective representation and characterization of biosynthetic pathways of glycosylation can be facilitated by mathematical modeling. This paper describes the expansion of a previously developed detailed model for N-linked glycosylation with the further application of the model to analyze MALDI-TOF mass spectra of human N-glycans in terms of underlying cellular enzyme activities. The glycosylation reaction network is automatically generated by the model, based on the reaction specificities of the glycosylation enzymes. The use of a molecular mass cutoff and a network pruning method typically limits the model size to about 10,000 glycan structures. This allows prediction of the complete glycan profile and its abundances for any set of assumed enzyme concentrations and reaction rate parameters. A synthetic mass spectrum from model-calculated glycan profiles is obtained and enzyme concentrations are adjusted to bring the theoretically calculated mass spectrum into agreement with experiment. The result of this process is a complete characterization of a measured glycan mass spectrum containing hundreds of masses in terms of the activities of 19 enzymes. In addition, a complete annotation of the mass spectrum in terms of glycan structure is produced, including the proportions of isomers within each peak. The method was applied to mass spectrometric data of normal human monocytes and monocytic leukemia (THP1) cells to derive glycosyltransferase activity changes underlying the differences in glycan structure between the normal and diseased cells. Model predictions could lead to a better understanding of the changes associated with disease states, identification of disease-associated biomarkers, and bioengineered glycan modifications.

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.

False positive reactivity of recombinant, diagnostic, glycoproteins produced in High Five insect cells: effect of glycosylation

Baculovirus-mediated expression of recombinant proteins for use in diagnostic assays is commonplace. We expressed a diagnostic antigen for cysticercosis, GP50, caused by the larval stage of Taenia solium, in both High Five and Sf9 insect cells. Upon evaluation of the specificity of recombinant GP50 (rGP50) in a western blot assay, we observed that 12.5% (21/168) of the serum samples from persons with a variety of parasitic infections other than cysticercosis reacted positive when rGP50 was produced in High Five cells. The same samples reacted negative when rGP50 was produced in Sf9 cells. The false positive reactivities of these other parasitic infection sera were abolished when rGP50, expressed in High Five cells, was deglycosylated. In addition, the same sera that reacted with rGP50 from High Five cells also reacted with recombinant human transferrin (rhTf) when expressed in High Five cells, but not Sf9 cells. High Five cells, but not Sf9 cells, modify many glycoproteins with a core alpha(1,3)-fucose. This same modification is found in the glycoproteins of several parasitic worms and is known to be immunogenic. Since the distribution of these worms is widespread and millions of people are infected, the use of recombinant proteins with N-linked glycosylation produced in High Five cells for diagnostic antigens is likely to result in a number of false positive reactions and a decrease in assay specificity.

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.

Purification, Characterization, and Cloning of a Spodoptera frugiperda Sf9 β-N-Acetylhexosaminidase That Hydrolyzes Terminal N-Acetylglucosamine on the N-Glycan Core

Paucimannosidic glycans are often predominant in N-glycans produced by insect cells. However, a beta-N-acetylhexosaminidase responsible for the generation of paucimannosidic glycans in lepidopteran insect cells has not been identified. We report the purification of a beta-N-acetylhexosaminidase from the culture medium of Spodoptera frugiperda Sf9 cells (Sfhex). The purified Sfhex protein showed 10 times higher activity for a terminal N-acetylglucosamine on the N-glycan core compared with tri-N-acetylchitotriose. Sfhex was found to be a homodimer of 110 kDa in solution, with a pH optimum of 5.5. With a biantennary N-glycan substrate, it exhibited a 5-fold preference for removal of the beta(1,2)-linked N-acetylglucosamine from the Man alpha(1,3) branch compared with the Man alpha(1,6) branch. We isolated two corresponding cDNA clones for Sfhex that encode proteins with >99% amino acid identity. A phylogenetic analysis suggested that Sfhex is an ortholog of mammalian lysosomal beta-N-acetylhexosaminidases. Recombinant Sfhex expressed in Sf9 cells exhibited the same substrate specificity and pH optimum as the purified enzyme. Although a larger amount of newly synthesized Sfhex was secreted into the culture medium by Sf9 cells, a significant amount of Sfhex was also found to be intracellular. Under a confocal microscope, cellular Sfhex exhibited punctate staining throughout the cytoplasm, but did not colocalize with a Golgi marker. Because secretory glycoproteins and Sfhex are cotransported through the same secretory pathway and because Sfhex is active at the pH of the secretory compartments, this study suggests that Sfhex may play a role as a processing beta-N-acetylhexosaminidase acting on N-glycans from Sf9 cells.

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).

Engineering intracellular CMP-sialic acid metabolism into insect cells and methods to enhance its generation

Previous studies have reported that insect cell lines lack the capacity to generate endogenously the nucleotide sugar, CMP-Neu5Ac, required for sialylation of glycoconjugates. In this study, the biosynthesis of this activated form of sialic acid completely from endogenous metabolites is demonstrated for the first time in insect cells by expressing the mammalian genes required for the multistep conversion of endogenous UDP-GlcNAc to CMP-Neu5Ac. The genes for UDP-GlcNAc-2-epimerase/ManNAc kinase (EK), sialic acid 9-phosphate synthase (SAS), and CMP-sialic acid synthetase (CSAS) were coexpressed in insect cells using baculovirus expression vectors, but the CMP-Neu5Ac and precursor Neu5Ac levels synthesized were found to be lower than those achieved with ManNAc supplementation due to feedback inhibition of the EK enzyme by CMP-Neu5Ac. When sialuria-like mutant EK genes, in which the site for feedback regulation has been mutated, were used, CMP-Neu5Ac was synthesized at levels more than 4 times higher than that achieved with the wild-type EK and 2.5 times higher than that achieved with ManNAc feeding. Addition of N-acetylglucosamine (GlcNAc), a precursor for UDP-GlcNAc, to the media increased the levels of CMP-Neu5Ac even more to a level 7.5 times higher than that achieved with ManNAc supplementation, creating a bottleneck in the conversion of Neu5Ac to CMP-Neu5Ac at higher levels of UDP-GlcNAc. The present study provides a useful biochemical strategy to synthesize and enhance the levels of the sialylation donor molecule, CMP-Neu5Ac, a critical limiting substrate for the generation of complex glycoproteins in insect cells and other cell culture systems.

Comparing N-glycan processing in mammalian cell lines to native and engineered lepidopteran insect cell lines

In the past decades, a large number of studies in mammalian cells have revealed that processing of glycoproteins is compartmentalized into several subcellular organelles that process N-glycans to generate complex-type oligosaccharides with terminal N -acetlyneuraminic acid. Recent studies also suggested that processing of N-glycans in insect cells appear to follow a similar initial pathway but diverge at subsequent processing steps. N-glycans from insect cell lines are not usually processed to terminally sialylated complex-type structures but are instead modified to paucimannosidic or oligomannose structures. These differences in processing between insect cells and mammalian cells are due to insufficient expression of multiple processing enzymes including glycosyltransferases responsible for generating complex-type structures and metabolic enzymes involved in generating appropriate sugar nucleotides. Recent genomics studies suggest that insects themselves may include many of these complex transferases and metabolic enzymes at certain developmental stages but expression is lost or limited in most lines derived for cell culture. In addition, insect cells include an N -acetylglucosaminidase that removes a terminal N -acetylglucosamine from the N-glycan. The innermost N -acetylglucosamine residue attached to asparagine residue is also modified with alpha(1,3)-linked fucose, a potential allergenic epitope, in some insect cells. In spite of these limitations in N-glycosylation, insect cells have been widely used to express various recombinant proteins with the baculovirus expression vector system, taking advantage of their safety, ease of use, and high productivity. Recently, genetic engineering techniques have been applied successfully to insect cells in order to enable them to produce glycoproteins which include complex-type N-glycans. Modifications to insect N-glycan processing include the expression of missing glycosyltransferases and inclusion of the metabolic enzymes responsible for generating the essential donor sugar nucleotide, CMP- N -acetylneuraminic acid, required for sialylation. Inhibition of N -acetylglucosaminidase has also been applied to alter N-glycan processing in insect cells. This review summarizes current knowledge on N-glycan processing in lepidopteran insect cell lines, and recent progress in glycoengineering lepidopteran insect cells to produce glycoproteins containing complex N-glycans.

Biosynthesis of human-type N-glycans in heterologous systems

Insects, yeasts and plants generate widely different N-glycans, the structures of which differ significantly from those produced by mammals. The processing of the initial Glc2Man9GlcNAc2 oligosaccharide to Man8GlcNAc2 in the endoplasmic reticulum shows significant similarities among these species and with mammals, whereas very different processing events occur in the Golgi compartments. For example, yeasts can add 50 or even more Man residues to Man(8-9)GlcNAc2, whereas insect cells typically remove most or all Man residues to generate paucimannosidic Man(3-1)GlcNAc2N-glycans. Plant cells also remove Man residues to yield Man(4-5)GlcNAc2, with occasional complex GlcNAc or Gal modifications, but often add potentially allergenic beta(1,2)-linked Xyl and, together with insect cells, core alpha(1,3)-linked Fuc residues. However, genomic efforts, such as expression of exogenous glycosyltransferases, have revealed more complex processing capabilities in these hosts that are not usually observed in native cell lines. In addition, metabolic engineering efforts undertaken to modify insect, yeast and plant N-glycan processing pathways have yielded sialylated complex-type N-glycans in insect cells, and galactosylated N-glycans in yeasts and plants, indicating that cell lines can be engineered to produce mammalian-like glycoproteins of potential therapeutic value.

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.

Thermostable alpha-amylase production by an extreme thermophile Bacillus thermooleovorans

AIMS

alpha-Amylase production by a newly isolated thermophile, Bacillus thermooleovorans, was studied under different cultivation conditions.

METHODS AND RESULTS

The influence of various carbon and nitrogen sources on alpha-amylase production was quantified in batch fermentation in shake flasks. Starch and tryptone were observed to be the ideal carbon and nitrogen sources, respectively. Cultivation of the organism in a chemically defined medium consisting of glucose, riboflavin, cysteine, MgSO4, K2HPO4 and NaCl led to a near twofold increase in the production of alpha-amylase in comparison with that in the complex medium. The increase in enzyme production was achieved using vitamins and amino acids. When the organism was grown in a laboratory fermenter in the optimized complex medium, the noticeable effects were the near abolition of the lag phase, a 2.2-fold increase in enzyme production and a reduction in optimal production time from 12 to 4-5 h.

CONCLUSION

Enhancement of amylase production was achieved under various cultivation conditions.

SIGNIFICANCE AND IMPACT OF THE STUDY

Bacillus thermooleovorans produces a calcium-independent and thermostable amylase which can find use in starch saccharification.

Results of pediatric laser in situ keratomileusis

PURPOSE

To evaluate the results of laser in situ keratomileusis (LASIK) for uniocular high myopia in pediatric eyes.

SETTING

Dr. Agarwal's Eye Hospital, Chennai (Madras), India.

METHODS

Sixteen eyes that were treated by LASIK for uniocular high myopia were retrospectively analyzed. The mean patient age was 8.4 years +/- 1.83 (SD) (range 5 to 11 years). Laser in situ keratomileusis was performed using the Technolas Keracor 217 excimer laser and the Automated Corneal Shaper microkeratome, which created a 160 microm corneal lamellar flap. Postoperatively, patients were reviewed at 1 day, 1 week, and 1, 6, and 12 months. The examination included uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction, anterior segment evaluation, grading of haze based on a 5-point scale, intraocular pressure, corneal topography, and fundus evaluation. The Student t test was used for statistical analysis.

RESULTS

The charts of all patients were analyzed at the 12 month visit. The mean preoperative spherical equivalent (SE) was -14.88 +/- 3.69 diopters (D) (range -9.00 to -23.00 D) and the mean postoperative SE, -1.44 +/- 1.14 D (range 0 to -2.50 D) (P < .05). The safety index was 1.01 (mean postoperative BCVA 0.54 and mean preoperative BCVA 0.53; P = .77). The efficacy index was 0.53 (mean postoperative UCVA 0.28 and mean preoperative BCVA 0.53). None of the eyes had an induced astigmatism of more than 0.5 D. Twelve eyes regained their BCVA, 2 lost 1 line of BCVA, and 2 gained 1 line. Three eyes had grade 2 haze. No retinal complications were observed.

CONCLUSION

In this study, LASIK for uniocular high myopia in pediatric eyes provided encouraging results in the management of select cases of anisometropic amblyopia when other measures failed. A larger study with a longer follow-up is necessary to determine the long-term effects.

Characterization of high affinity monoclonal antibodies specific for chlamydial lipopolysaccharide

Pathogens belonging to the genus Chlamydia contain lipopolysaccharide with a 3-deoxy-D- manno- oct-2-ulosonic acid (Kdo) trisaccharide of the sequence alpha-Kdo-(2-->8)-alpha-Kdo-(2-->4)-alpha-Kdo. This lipopolysaccharide is recognized in a genus-specific pattern by murine monoclonal antibodies (mAbs), S25-23 and S25-2 (both IgG1kappa), which bind as the minimal structures the trisaccharide and the terminal Kdo-disaccharide, respectively. The variable domains of these mAbs were reverse transcribed from mRNA which was isolated from hybridomas and cloned as single-chain variable fragments (scFvs) in E.coli TG1. The kinetics of binding of whole antibodies, Fab fragments and scFvs to natural and synthetically modified ligands were determined by surface plasmon resonance (SPR) using synthetic neoglycoconjugates. As examples of an antibody-carbohydrate interaction involving anionic carboxyl groups on the ligand, we report that the affinities of these antibodies are higher than usually observed in carbo-hydrate-protein interactions (K(D)of 10(-3)to 10(-5)M). SPR analy-ses of monovalent Fab and scFv binding to the natural trisaccharide epitope gave dissociation constants of 770 nM for S25-2 and 350 nM for S25-23, as determined by global fitting (simultaneous fitting of several measurements at different antibody concentrations) of sensorgram data to a one-to-one interaction model. Local fitting (separate fitting of individual sensorgram data at different antibody concentrations) and Scatchard analysis of the data gave kinetic and affinity constants that were in good agreement with those obtained by global fitting. The SPR data also showed that while S25-2 bound well to several Kdo disaccharides and carboxyl-reduced Kdo ligands, S25-23 did not. Identification of amino acids in the complementarity determining regions revealed the presence of a large number of positively charged amino acids which were located towards the center of the combining site, thus suggesting a different recognition mechanism than that observed for neutral ligands. The latter mainly involves aromatic amino acids for hydrophobic stacking inter-actions and hydrogen bonds.