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.

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.

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.

Aortic atherosclerosis and perioperative stroke in patients undergoing coronary artery bypass: role of intra-operative transesophageal echocardiography

Intra-operative transesophageal echocardiography was performed in 126 patients undergoing coronary artery bypass grafting. Significant protruding atheromas (grade IV and V; Katz et al., 1992) were present in 12 patients (9.5%). Protruding atheromas had significantly higher incidence in patients above 60 years in age. Preoperative assessment with chest roentgenography and angiography, as well as intra-operative assessment by surgical palpation proved to be insensitive in detecting aortic atheromas. Out of four patients with grade V atheromas, two (50%) developed right hemiplegia postoperatively. For the rest, patients with grade V atheromas and eight patients with grade IV atheromas, surgical technique was modified and that helped in preventing occurrence of perioperative stroke.

Biochemical and histopathological changes following dermal exposure to paraphenylene diamine in guinea pigs

The guinea pigs were dermally exposed to paraphenylene diamine (PPD) at a dose level of 0.1 ml day-1 of a 1.0% (w/v) solution of PPD for 1, 3, 5 and 7 days. The absorption of PPD and its effects on lipid peroxidation, glutathione, histamine and several enzymes were assessed in skin and serum. Histopathological changes in liver, kidney and skin were examined also. The findings of the study indicated that PPD exposure resulted in significantly increased levels of lipid peroxidation and histamine contents in skin. The activity of enzymes increased significantly in skin and serum. PPD exposure also showed degenerative changes in liver and hyperkeratosis together with infiltration of cells in the dermis. Biochemical defects and histopathological changes in skin and serum correlated with the duration of exposure.

Crystal structure of T4-lysozyme generated from synthetic coding DNA expressed in Escherichia coli

The polypeptide produced by expressing a chemically synthesized gene coding for the amino-acid sequence of T4-lysozyme has been crystallized and subjected to X-ray diffraction. The crystal structure has been refined to a standard R-factor of 0.191 for data between 8 and 2 A resolution. The refined model is essentially the same as the well-known structure of wild-type T4-lysozyme determined previously by Matthews et al. (1987). Some small changes in the C-terminal region, which is important in maintaining the folded structure, have been noted. In addition to confirming that the synthetic gene product is very close to the wild type, this structure provides a benchmark for protein engineering experiments on the folding and the catalytic activity of this molecule by the method of gene synthesis.

B lymphocytic lymphoma (large cell) of possible splenic marginal zone origin presenting with prominent splenomegaly and unusual cordal red pulp distribution

Two cases of large cell lymphoma, B-cell type, primarily involving the red pulp of the spleen rather than the white pulp are described. A number of unusual features suggest that this may be a lymphoma originating from a distinct splenic B-cell lymphocyte whose origin may be the marginal zone of the spleen or the splenic cords. The patients presented with splenomegaly, cytopenias, and no peripheral lymphadenopathy. The gross appearance of the spleens was beefy red without tumor nodules. The tumor cells were primarily in the splenic cords and surrounding residual normal white pulp. There was a minimal hemic phase. The tumor cells had abundant cytoplasm, surface IgM, IgD, kappa, and FC receptors, tartrate-resistant acid phosphatase, but no alkaline phosphatase or interleukin-2 receptors. They had a similar DNA aneuploidy. The most unusual feature was that tumor cells in both cases had phagocytic properties. These lymphomas may be clinically more indolent than their follicular center counterparts.