Impact of Socio-demographic Variables, Surgical Techniques and Risk Factors on the Outcome of Coronary Artery Bypass Graft Surgery among Bangladeshi Population.

This study was intended to evaluate the pathological outcome of cardiopulmonary bypass whilst considering socio-demographic variables and surgical technique on early postoperative results following coronary artery bypass graft (CABG) surgery in patients at a tertiary level hospital in Bangladesh. This observational study evaluated a total of 880 patients with ischemic heart disease in Bangabandhu Sheikh Mujib Medical University, Bangladesh from 2011 to 2019 who were undergoing an isolated CABG surgery. In this current study, the population divided into two groups- Group A: Off-pump CABG (n=440) and Group B: On-pump CABG (n=440). The mean age of the patients was 55.25±5.0 years in off-pump and 50.75±5.2 years in the on-pump group. Risk factors, including smoking, hypertension, and hyperlipidemia, were predominant in both study groups. Total operative time was notably higher in the on-pump CABG group. However, grafting time was more in the off-pump CABG procedures. Postoperative neurological deficits were higher amongst the on-pump CABG population. The mean time of mechanical ventilation, intensive care unit (ICU) stay, total hospital stay, and mortality was notably higher in the on-pump CABG group. Moreover, the number of mortalities in on-pump CABG patients was primarily due to the low output syndrome, failure of weaning from cardiopulmonary bypass (CPB) and sudden cardiac arrest. Off-pump CABG is now more acceptable due to its potentiality to avoid CPB induced complications, aortic cannulation, and cross-clamping. Cardiac arrest in on-pump CABG induces global ischemia and reperfusion injury to the cardiac muscle. Besides, the Off-pump CABG provides a conspicuous survival advantage compared to the on-pump CABG, in association with a notable reduction in postoperative morbidity and mortality.

Diagnostic Dilemma of Frozen Shoulder in Post CABG Patient: A Case Report.

Frozen shoulder, also known as adhesive capsulitis, is a condition featured by stiffness and pain in shoulder joint. In this report, we present a case of 58 years old diabetic male patient with the history of coronary artery bypass grafting (CABG) 06 months back. He presented with persistent right shoulder pain for 05 months. Clinical examinations reveal restriction of the right shoulder joint movement in all directions and wasting of the right supraspinatus, infraspinatus and trapezius muscles. Both active and passive range of motions was restricted with painful right shoulder joint. Pain free abduction range was about 40 degrees in right shoulder. Plain X-ray of right shoulder joint and other relevant investigations show normal findings. Considering the clinical and laboratory findings decision was taken to treat the patient with exercise, pain killer and ultrasound therapy which were found to be optimistic.

A 15 Year's Experience with Minimally Invasive Mitral Valve Replacement in Bangladesh.

This study was aimed to compare the long-term outcomes and survival rate among mitral valve replacement using thoracotomy and standard median sternotomy in a single surgeon's practice. Total 250 patients were evaluated; Group I (n=65) patients had anterolateral thoracotomy and Group II (n=185) had standard median sternotomy for valve replacement. Mean age was 25.1±5 years in Group I and 41.8±10.5 years in Group II. Female was predominant in Group I. Total operative time and bypass time was statistically significant in Group I (235.5±25.8 minutes; 84.2±12.75 minutes) in contrast to Group II (203.8±15.5 minutes; 71.5±10.5 minutes). Incision scar was not visible in females in Group I but full incision scar was visible in Group II. Post-operative ICU stay duration was significant high in Group II. Though, wound infection incidence was 0% in Group I; however, 9.73% patient had wound infection in Group II. Only 1.62% patient developed unstable sternum in Group II. Most of the patients from both study group were in regular follow up and 1-year mortality rate was 4.62% and 5.94% in Group I and Group II respectively. Mitral valve replacement through a right anterolateral thoracotomy is easy and safe to perform; while getting maximum benefits for the patients. Besides satisfactory cosmetic outcome especially in female, this approach provides better exposure to mitral apparatus even in patients with small left atrium, cost effectiveness, less duration of hospital stays and absence of the risk for unstable sternum.

Fast Tract Anesthesia Using Isoflurane and Propofol During Off-pump Coronary Artery Bypass Graft Surgery.

This study aimed to evaluate myocardial protective effect of isoflurane and propofol as a fast tract anesthesia in off pump coronary artery bypass graft surgery by measuring postoperative cardiac enzyme Troponin-I, and liver enzyme. The study was conducted on 260 patients scheduled to undergo elective off pump coronary artery bypass graft surgery. Patients were randomly allocated to receive either isoflurane or propofol anesthesia and was aimed to extubated within 6 hours. Troponin-I levels were measured preoperatively, at arrival in postoperative intensive care unit, at 12, 24, 48, 72 hours and 4 weeks following surgery. Liver function was also assessed and compared between preoperative and postoperative values. There is no difference in Troponin-I levels between the two studies groups at observed pre and post-operative time intervals. Fast tract anesthesia using isoflurane and propofol provides same myocardial protection during and after OPCABG and overall outcome was excellent.

Cardiofacial Syndrome: A Rare Case Report.

Cardiofacial syndrome is associated with facial abnormality with congenital heart disease. Here, we report a case of cardiofacial syndrome having anotia and facial nerve palsy on the right side in combination with infundibular pulmonary stenosis and patent ductus arteriosus which is a rare presentation of cardiofacial syndrome. A 6 years old girl presented to department of Cardiac surgery of Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh with the complaints of shortness of breath on exertion since 2 years of age. Her physical examination revealed right sided anotia and facial nerve palsy associated harsh ejection systolic murmur in upper left parasternal area. Echocardiography showed critical infundibular pulmonary stenosis with a small patent ductus arteriosus. She underwent ligation of patent ductus arteriosus and excision of infundibular muscular bands and discharged to home without any complication. Any child presented with facial abnormality should be checked for any cardiac abnormality for early intervention and better management of the patient.

Pregnancy Outcome with Prosthetic Heart Valve in Bangladesh: A Retrospective Cohort Study.

The aim of this retrospective cohort study was to evaluate the occurrence of the maternal and fetal outcome during pregnancy and immediately after delivery in women with prosthetic heart valve, especially with oral anticoagulants therapy that must be weighed against the risk of intracardiac thrombosis. This study was undertaken at Department of Cardiac surgery, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh from January 2012 to December 2017. A total of 82 pregnancies with heart valve prosthesis were evaluated in two groups: Group I (n=58) includes pregnancy with mechanical heart valve, while Group II (n=24) includes pregnancy with bioprosthetic valve. The mean age of patients was 25.7±2.5 years and 24.9±5.5 years in Group I and Group II respectively. Approximately 70% pregnancies ended in healthy live births, however about 75% of study population developed maternal complications in Group I, which is significantly higher than Group II. First trimester spontaneous miscarriage was statistically significant between two groups (p value <0.005). Mean birth weight and mean APGAR score was found normal in both study group. Majority of the patients were found in good health status during and after pregnancy. Proper antenatal care and early risk stratification are the fundamental measures to improve the maternal and fetal outcome in a patient with prosthetic heart valve.

Ectopic Parathyroid Adenoma: Surgical Correction and its Complication Management.

Ectopic parathyroid are most frequently found in the anterior mediastinum, in association with the thymus or the thyroid gland. Ectopic parathyroid glands are a major cause of persistent and recurrent Hyperparathyroidism. We report a case of 65-year-old female was referred from Surgical Endocrine department to the department of Cardiac Surgery on 20 September, 2017 in Bangabandhu Sheikh Mujib Medical University with parathyroid crisis due to an ectopic mediastinal parathyroid adenoma with her serum calcium and PTH markedly increased in short time. Computed tomography of the chest and lower neck showed an ovoid soft tissue density area measuring about 25×20×15mm in the anterior mediastinum. Technetium-99m-sestamibi (MIBI) scintigraphy scan showed positive and detected localized parathyroid adenoma/hyperplasia in superior mediastinum. Ectopic parathyroid adenoma resection was performed via median sternotomy approach. But after 4 hours patient developed the color change of the left arm due to acute left upper limb ischemia of unknown cause for which the patient was rushed to operation theatre suspecting it to be embolic occlusion and managed by both surgical and medical therapy.

Comparison of Two Laboratory Methods of Preservation for Preclinical Preparation of Bovine Aortic Heart Valve Suitable for Human Use.

The present experimental study was carried out as an experimental study in the department of Cardiac Surgery at Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh from July 2011 to May 2013 to see which preservation techniques give us morphologically and histologically suitable xenograft heart valve for clinical use. We reviewed 20 bovine aortic valves in 2 years. Each of 10 samples was grouped as glutaraldehyde (1.5%) preservation and cryopreservation (-180°C). After collecting each specimen, sterilization of valve was done in low concentration of sterile antibiotic solution (CLPVA). Then 10 dissected valves were immersed each in 250ml of 1.5% glutaraldehyde solution at 4°C. Another 10 dissected valves were placed in a solution of 100ml 10% DMSO and suspended in vapor phase of liquid nitrogen at -180°C. Then after 4 weeks, the valves were examined for naked eye (color change, shrinkage, swelling, pliability, stiffness of leaflet) and histological (endothelial cells, leaflet extracellular matrix preservation, fibroblast preservation, inflammation, necrosis and other pathological conditions on valve leaflet) examination. Statistical analysis showed that morphological changes were not significant in both groups but in histological examination, cryopreservation showed effective preservation of fibroblast and extracellular matrix than glutaraldehyde preservation.

Comparative Study between the Use of Multidose Standard Cardioplegia and Long Acting Del Nido Cardioplegia during Intracardiac Repair for Tetralogy of Fallot in Pediatric Patients.

Pediatric myocardium is unique from mature myocardium; thus, the use of adult cardioplegia for pediatric cardiac operations may provide suboptimal myocardial protection. It is found that children undergoing heart surgery show evidence of less myocardial damage when del Nido cardioplegia is used instead of a standard cardioplegic solution. Del Nido cardioplegia solution provides a depolarized hyperkalaemic arrest lasting up to 60 minutes, reduces spontaneous and inducible activity during arrest, and prevents hyper contraction during early reperfusion. In this single blind randomized trial, a total of 60 patients underwent intra cardiac repair for TOF in National Institute of Cardiovascular Diseases, Dhaka, Bangladesh from July 2014 to January 2016 fulfilling inclusion and exclusion criteria. They were randomly assigned in two groups- 30 patients in Del Nido group (Group A) and 30 patients in standard group (Group B). Comparison between groups was done by Chi square test and Student's test. All data were analyzed by SPSS 20.0 for windows. P value less than 0.05 was considered as significant. There was statistically significant difference among the patients in terms of mean total initial cardioplegia volume, mean number of additional dose, mean additional dose amount, mean cross clamp time, mean CPB time (331.67±188.07 vs. 458.67±226.62, p=0.022; 0.13±0.35 vs. 1.27±0.89, p=0.000; 23.33±60.76 vs. 336.83±259.6, p=0.000; 45.10±10.35 vs. 59.23±23.21, p=0.003; 89.30±15.73 vs. 111.10±29.23, p=0.001 respectively). Mean post operative serum troponin I level at arrival in ICU and after 24 hours between two groups were statistically significantly different (55.60±32.91 vs. 83.5±58.99; p=0.024 and 13.01±5.84 vs. 18.16±9.51; p=0.014 respectively). The mean ventilation duration, mean ICU stay were also statistically significant. This study showed that cardiac arrest with Del Nido cardioplegia during intra cardiac repair for TOF was associated with improved myocardial protection over standard cardioplegia in terms of reduced CPB and cross clamp times, lower total volume of cardioplegia.

Surgical Management of a Critical Ischemic Mitral Regurgitation Patient.

Functional ischemic mitral regurgitation is strongly associated with poor outcomes in patient with coronary artery disease. The best management for mitral regurgitation at the time of coronary revascularization remains controversial. We report, a case of 58 years-old men admitted to GKNM hospital, Coimbatore, Tamil Nadu, India with chest pain and respiratory distress for last 6 hours during my fellowship training in that hospital. ECG showed acute antero-septal MI. The transthoracic echocardiogram revealed severe left ventricular dysfunction with moderate mitral regurgitation. Coronary angiogram revealed triple vessels disease. We planned for early CABG. But the patient suddenly developed severe respiratory distress with ventricular tachycardia. Patient managed with the support of invasive ventilation and IABP. After that, CABG along with mitral valve repair was done under cardiopulmonary bypass. The patient showed excellent symptomatic improvement during his early post-operative period. Mitral valve repair along with CABG may be a preferable treatment option for patient with Ischemic heart disease with moderate mitral regurgitation.

Coronary Artery Bypass Graft with Endarterectomy and Stent Removal in Patient with Multivessel in Stent Restenosis.

In the age of stent deployment after balloon angioplasty. In stent restenosis (ISR) has become a major concern. Various coronary interventional measures and coronary artery bypass graft (CABG) has employed to manage the ISR. Although CABG seems to offer advantages over other coronary intervention methods in patients with multi vessel ISR; lack of appropriate graftable vessels often make the surgery difficult and end up with incomplete revascularization. Coronary endarterectomy with stent removal mitigated some of the limitations of CABG but initial results of this surgical measure were not favorable. Later, with improvement of surgical technique and meticulous anticoagulant therapy along with CABG showed promising result but till date only few cases have been reported. Here, we are reporting a case of 65 years old lady who underwent CABG along with endarterectomy with stent removal after she had developed stent restenosis in three vessels. This diabetic and hypertensive patient presented with chest pain and shortness of breath which was developed within three months of PCI with stent deployment in three vessels. Angiogram done prior to admission in the cardiac surgery department reveals restenosis in all the three stented vessels. CABG was done and three grafts given in LIMA to LAD, RSVG to OM and RCA. Endarterectomy done on LAD and RCA with stent removal from RCA. Postoperative anticoagulant therapy was strictly maintained. Patient's postoperative period remained eventless other than superficial wound infection. With skilled hand capable of handling highly technique demanding surgery and postoperative anticoagulation maintenance; endarterectomy along with CABG seems to be safe solution for multi vessel ISR with diffuse coronary artery disease.

Non-migratory tumorigenic intrinsic cancer stem cells ensure breast cancer metastasis by generation of CXCR4(+) migrating cancer stem cells.

Although the role of metastatic cancer stem cells (mCSCs) in tumor progression has been well documented, our study reveals a hitherto unidentified role of tumorigenic intrinsic CSCs (iCSCs) in breast cancer metastasis. We show that unlike highly migratory mCSCs residing in the breast tumor disseminating/peripheral regions, iCSCs populate the inner mass of the tumor and are non-migratory. However iCSCs, via paracrine signaling, induce conversion of non-stem cancer cells to CSCs that (i) are identical to the previously reported mCSCs, and (ii) in contrast to iCSCs, express chemokine receptor, chemokine (C-X-C motif) receptor 4 (CXCR4), which is crucial for their metastatic potential. These mCSCs also demonstrate high in vivo tumorigenicity. Physical non-participation of iCSCs in metastasis is further validated in vivo, where only mCSCs are found to exist in the metastatic sites, lymph nodes and bone marrow, whereas the primary tumor retains both iCSCs and mCSCs. However, iCSCs ensure metastasis since their presence is crucial for deliverance of highly metastatic CXCR4(+) mCSCs to the migrating fraction of cells. Cumulatively, these results unveil a novel role of iCSCs in breast cancer metastasis as parental regulators of CXCR4(+) mCSCs, and highlight the therapeutic requisite of targeting iCSCs, but not CXCR4(+) mCSCs, to restrain breast cancer metastasis from the root by inhibiting the generation of mCSCs from iCSCs. Considering the pivotal role of iCSCs in tumor metastasis, the possibility of metastasis to be a 'stem cell phenomena' is suggested.

A Rapid and Reliable End-To-End Anastomosis Technique for Emergency Vascular Surgery--A Case Report.

A 28 year old male presented to us with 8 hours old open fracture of distal shaft of left femur which was already stabilized with external fixator but had no palpable distal pulse both clinically and on doppler examination. He underwent a primary repair following limited segmental resection. Commonly end-to-end anastomosis techniques following transection of arteries include interrupted and continuous suturing with or without 'parachuting' of the vessel or graft. Here we offer a rapid and reliable technique with following advantages: i) operating system always towards the surgeon, ii) posterior row of suture placed as both ends are well visualized, iii) less chance of catching posterior wall, iv) flushing performed easily before completing anterior row suture. Upto 2nd post operative day anticoagulant used in the form of inj. Heparin 2500 IU subcutaneously 8 hourly and patient was discharged from hospital on 3rd post operative day with presence of good distal pulses both on clinical and Doppler examination. Fourteen days later, on follow up Duplex study showed normal arterial flow without any stenosis or occlusion.

Surgical Closure of Atrial Septal Defect with High Pulmonary Vascular Resistance--A Case Report.

We have reported a case of successful pericardial patch closure of atrial septal defect with high pulmonary vascular resistance in a 32 years aged male. Diagnosis was confirmed by Doppler Echocardiography, Cardiac catheterization and lung biopsy. Before starting (orally) bosentan pulmonary arterial pressure was 105 mm Hg and pulmonary vascular resistance was 8 wood's unit. Bosentan was started at a dosage of 125 mg per day (62.5 mg twice a day) for 4 months before operation in this case. Just day before operation pulmonary arterial pressure was 87 mm Hg. Bosentan lowered pulmonary arterial pressure and reversed remodeling of pulmonary arteries and allowed surgical correction. During the post operative course, partial pressure of oxygen was significantly decreased and bilateral radiolucent opacity was present in lower zone of both lungs. All these were managed successfully in postoperative period. This case report has demonstrated that surgical correction of an atrial septal defect is feasible but requires long time pre and post operative treatment with pulmonary vasodilators.

ROS-PIASγ cross talk channelizes ATM signaling from resistance to apoptosis during chemosensitization of resistant tumors.

With the existing knowledge of ATM's role in therapeutic resistance, the present study aimed at identifying the molecular mechanisms that influence ATM to oscillate between chemoresistance and chemosensitivity. We observed that the redox status of tumors functions as a major determinant of ATM-dependent 'resistance-to-apoptosis' molecular switch. At a low reactive oxygen species (ROS) condition during genotoxic insult, the ATM/sumoylated-IKKγ interaction induced NFκB activation that resisted JNK-mediated apoptosis, whereas increasing cellular ROS restored ATM/JNK apoptotic signaling. A search for the upstream missing link revealed that high ROS induces oxidation and ubiquitin-mediated degradation of PIASγ, thereby disrupting PIASγ-IKKγ cross talk, a pre-requisite for IKKγ sumoylation and subsequent NFκB activation. Interruption in the PIASγ-mediated resistance pathway channels ATM signaling toward ATM/JNK pro-death circuitry. These in vitro results also translated to sensitive and resistant tumor allograft mouse models in which low ROS-induced resistance was over-ruled in PIASγ knockout tumors, while its overexpression inhibited high ROS-dependent apoptotic cues. Cumulatively, our findings identified an unappreciated yet critical combinatorial function of cellular ROS and PIASγ in regulating ATM-mediated chemosensitization of resistant tumors. Thus, therapeutic strategies employing ROS upregulation to inhibit PIASγ during genotoxic therapy may, in future, help to eliminate the problems of NFκB-mediated tumor drug resistance.

Human adenovirus type 8 genome typing.

Human adenovirus type 8 (HAdV-8) is a major causative agent of epidemic keratoconjunctivitis, which is frequently associated with community, industrial and nosocomial outbreaks. Restriction endonuclease (RE) analysis discriminates HAdV-8 isolates into genome types, making it possible to correlate between genomic variants, virulence and outbreak potential. RE analysis is performed using two sets of classification criteria, an Asian and a European system. So far, genome types HAdV-8A-8K and HAdV-8/D1-D12 have been included in the Asian and European classifications, respectively. Conventionally followed RE analysis has some inherent problems, such as the use of a neutralization test for HAdV-8 typing, which may misidentify some recombinant adenoviruses as HAdV-8 due to cross-reaction, the lack of a complete restriction profile for all genome types for purposes of comparison, and the absence of enzyme codes in the Asian classification system. In this review, we propose typing of HAdV-8 with phylogenetic analysis of the hexon and fibre genes prior to RE analysis due to the emergence of many recombinant types. Schematic restriction profiles for both classification systems were created by compiling all the published reports on genome types, and enzyme codes were included for the Asian classification system. The updated and simplified stepwise approach for HAdV-8 genome typing presented here could be useful for identifying either existing genome types or novel ones.

Restoration of tumor suppressor p53 by differentially regulating pro- and anti-p53 networks in HPV-18-infected cervical cancer cells.

Abrogation of functional p53 is responsible for malignant cell transformation and maintenance of human papilloma virus (HPV)-infected cancer cells. Restoration of p53 has, therefore, been regarded as an important strategy for molecular intervention of HPV-associated malignancies. Here we report that differential regulation of pro- and anti-p53 setups not only upregulates p53 transcription but also stabilizes and activates p53 protein to ensure p53-induced apoptosis in HPV-18-infected cervical cancer. Functional restoration of p53 can be achieved by non-steroidal anti-inflammatory drug celecoxib via multiple molecular mechanisms: (i) inhibition of p53 degradation by suppressing viral oncoprotein E6 expression, (ii) promoting p53 transcription by downmodulating cycloxygenase-2 (Cox-2) and simultaneously retrieving p53 from Cox-2 association and (iii) activation of p53 via ataxia telangiectasia mutated-/p38 mitogen-activated protein kinase-mediated phosphorylations at serine-15/-46 residues. That restored p53 is functional has been confirmed by its ability of transactivating Bax and p53-upregulated modulator of apoptosis, which in turn switch on the apoptotic machinery in these cells. Studies undertaken in biopsy samples of cervical carcinoma further validated celecoxib effect. Our approaches involving gene manipulation and pharmacological interference finally highlight that celecoxib alters pro- and anti-p53 networks, not in isolation but in concert, to rejuvenate p53-dependent apoptotic program in HPV-infected cervical cancer cells.

Carotid intima media thickness: an independent marker for assessment of macrovascular risk in diabetic patients.

In view of the global epidemic of diabetes with India being the hottest reservoir of the disease, it was tried to identify carotid intima media thickness as a surrogate marker for atherosclerosis in diabetic subjects. The study becomes more relevant because diabetes is now considered a disease of the endothelium and a risk equivalent of coronary atherosclerosis (paradigm shift). The study incorporated 41 normotensive patients of diabetes and 31 age and sex matched controls. Plasma glucose and lipid profiles were assessed in all and the carotid intima media thickness was measured. Results were statistically analysed for significance and correlation coefficient between values of plasma glucose and carotid intima media thickness. Results clearly showed that carotid intima media thickness abnormality can pick up atherosclerosis even if the lipid parameters are nearly normal. So it crystallises from this small study that, as a non-invasive test carotid intima media thickness is a better and early predictor of atherosclerosis in diabetic subjects. It also revealed the linear relationship between both fasting and postprandial blood sugar with carotid intima media thickness.

Heterogeneity of the fibre sequence in subgenus C adenoviruses.

AIMS: To determine the nucleotide sequences of adenovirus (Ad) types 1 and 6 fibre genes; to clarify the molecular basis of the distinct haemagglutination properties of subgenus C Ads and their phylogenetic relations. METHODS: Human Ad1 and Ad6 fibre genes were sequenced from genomic DNA by direct sequencing. Primer selection was based on alignment of the fibre gene of human Ad serotypes Ad2 and Ad5. Fibre based subgenus C specific polymerase chain reaction (PCR) was performed to check for deletions in field isolates of Ad6, as revealed by sequence analysis of the Ad6 prototype. A phylogenetic tree was constructed from the predicted amino acid (AA) sequences of the fibre gene of important Ads. RESULTS: Ad1 and Ad6 comprise 1746 and 1584 nucleotides, encoding 582 and 528 AA, respectively. Ad6 showed deletions in motifs 15-17 (51 AA) of the shaft when compared with Ad1, Ad2, and Ad5. Subgenus C specific PCR with both prototype and field isolates also showed deletions in Ad6. In the shaft and knob, AA homology was 58.82-72.91% and 68.89-74.59%, respectively. The tail was 100% conserved. Phylogenetically, Ad1 and Ad6, including Ad2 and Ad5, formed a subgenus specific cluster, like other serotypes. CONCLUSIONS: The fibre gene (including the knob region) of subgenus C Ads is heterogeneous, providing the molecular basis for lack of crossreactivity in the haemagglutination inhibition test. This heterogeneity could be helpful in fibre based genotyping of subgenus C field isolates. Phylogeny might be useful for subgenus specific identification of important field strains.

Serological and genetic characterisation of a unique strain of adenovirus involved in an outbreak of epidemic keratoconjunctivitis.

AIMS: To characterise a novel strain of adenovirus (Ad) type Ad8 (genome type Ad8I) involved in an epidemic keratoconjunctivitis (EKC) outbreak in Hiroshima city using serological testing and sequence analysis of the fibre and hexon gene. METHODS: A neutralisation test (NT) was performed in microtitre plates containing a confluent monolayer of A549 cells using 100 tissue culture infectious doses of virus and type specific antisera. The haemagglutination inhibition test was also carried out in microtitre plates with rat erythrocytes using four haemagglutination units of virus and twofold dilutions of serum. The fibre gene was sequenced by generating overlapping polymerase chain reaction products or by direct sequencing of genomic DNA. Primer selection was based on alignment of the fibre genes of human adenovirus serotypes Ad8, Ad19, Ad37, Ad9, and Ad15 available from Gene Bank. RESULTS: The virus strain was specifically neutralised by anti-Ad8 antibodies, although there was a major crossreaction with anti-Ad9 antibodies. Haemagglutination was equally inhibited by anti-Ad8 and anti-Ad9 antibodies. The predicted amino acid sequences of the hypervariable regions (HVRs) of the Ad8I hexon gene showed higher homology with Ad9 (83.3%) than with Ad8 (62.0%). However, the Ad8I fibre knob was more homologous to Ad8 (94.4%) than to Ad9 (91.6%). CONCLUSIONS: Ad8I is a unique strain of adenovirus because of its lower genomic homology with Ad8, major crossreactivity with Ad9 in NT, and mixed genetic organisation of HVRs of the hexon gene. These factors may have enabled the virus to circumvent acquired immunity, resulting in the outbreak.