Implementation of a clinical pathway for the surgical treatment of colorectal cancer during the COVID-19 pandemic.

AIM: This report summarizes the early experience of implementing elective colorectal cancer surgery during the COVID-19 pandemic. METHODS: A pathway to minimize the risk of including COVID-19-positive patients for elective surgery was established. Prioritization and additional safety measures were introduced into clinical practice. Minimal invasive surgery was used where appropriate. RESULTS: Thirty-eight patients were prioritized, and 23 patients underwent surgery (eight colon, 14 rectal and one anal cancer). The minimal invasive surgery rate was 78%. There were no major postoperative complications or patients diagnosed with COVID-19. Histopathological outcomes were similar to normal practice. CONCLUSION: A safe pathway to offer standard high-quality surgery to colorectal cancer patients during the COVID-19 pandemic is feasible.

Effect of 220Rn gas concentration distribution on its transmission from a delay chamber: evolving a CFD-based uniformity index.

(220)Rn mitigation can be achieved by delay chamber technique, which relies on the advantage of its short half-life. However, flow rate as well as inlet-outlet position for the delay chamber can have a significant impact on (220)Rn concentration distribution patterns and hence transmission factor. In the present study, computational fluid dynamics simulations to estimate the concentration distribution has been carried out in a chamber of 0.5 m(3) for the combination of six different inlet-outlet positions and five different flow rates. Subsequently, the transmission factor (TF) for the chamber was evaluated and found to be highly dependent on the flow rate and inlet-outlet positions. For ease of scale up, the dependency of TF on the flow rate and the inlet-outlet positions is best summarised by relative transmission factor (RTF), which is the ratio of the TFs for the case of inlet and outlet on different faces to that on the same face.

Molecular Docking and Interactions of Pueraria Tuberosa with Vascular Endothelial Growth Factor Receptors.

Pueraria tuberosa is known for its therapeutic potentials in cardiovascular disorders, but its effect in angiogenesis has not been studied so far. In this study, a computational approach has been applied to elucidate the role of the phytochemicals in inhibition of angiogenesis through modulation of vascular endothelial growth factor receptors: Vascular endothelial growth factor receptor-1 and vascular endothelial growth factor receptor-2, major factors responsible for angiogenesis. Metabolite structures retrieved from PubChem and KNApSAcK - 3D databases, were docked using AutoDock4.2 tool. Hydrogen bond and molecular docking, absorption, distribution, metabolism and excretion and toxicity predictions were carried out using UCSF Chimera, LigPlot(+) and PreADMET server, respectively. From the docking analysis, it was observed that puerarone and tuberostan had significant binding affinity for the intracellular kinase domain of vascular endothelial growth factor receptors-1 and vascular endothelial growth factor receptor-2 respectively. It is important to mention that both the phytochemicals shared similar interaction profile as that of standard inhibitors of vascular endothelial growth factor receptors. Also, both puerarone and tuberostan interacted with Lys861/Lys868 (adenosine 5'-triphosphate binding site of vascular endothelial growth factor receptors-1/vascular endothelial growth factor receptors-2), thus providing a clue that they may enforce their inhibitory effect by blocking the adenosine 5'-triphosphate binding domain of vascular endothelial growth factor receptors. Moreover, these molecules exhibited good drug-likeness, absorption, distribution, metabolism and excretion properties without any carcinogenic and toxic effects. The interaction pattern of the puerarone and tuberostan may provide a hint for a novel drug design for vascular endothelial growth factor tyrosine kinase receptors with better specificity to treat angiogenic disorders.

Molecular Modeling and Docking Study to Elucidate Novel Chikungunya Virus nsP2 Protease Inhibitors.

Chikungunya is one of the tropical viral infections that severely affect the Asian and African countries. Absence of any suitable drugs or vaccines against Chikungunya virus till date makes it essential to identify and develop novel leads for the same. Recently, nsP2 cysteine protease has been classified as a crucial drug target to combat infections caused by Alphaviruses including Chikungunya virus due to its involvement viral replication. Here in, we investigated the structural aspects of the nsP2 protease through homology modeling based on nsP2 protease from Venezuelan equine encephalitis virus. Further, the ligands were virtually screened based on various pharmacological, ADME/Tox filters and subjected to docking with the modeled Chikungunya nsP2 protease using AutoDock4.2. The interaction profiling of ligand with the protein was carried out using LigPlot(+). The results demonstrated that the ligand with PubChem Id (CID_5808891) possessed highest binding affinity towards Chikungunya nsP2 protease with a good interaction profile with the active site residues. We hereby propose that these compounds could inhibit the nsP2 protease by binding to its active site. Moreover, they may provide structural scaffold for the design of novel leads with better efficacy and specificity for the nsP2 protease.

Study of indoor radon distribution using measurements and CFD modeling.

Measurement and/or prediction of indoor radon ((222)Rn) concentration are important due to the impact of radon on indoor air quality and consequent inhalation hazard. In recent times, computational fluid dynamics (CFD) based modeling has become the cost effective replacement of experimental methods for the prediction and visualization of indoor pollutant distribution. The aim of this study is to implement CFD based modeling for studying indoor radon gas distribution. This study focuses on comparison of experimentally measured and CFD modeling predicted spatial distribution of radon concentration for a model test room. The key inputs for simulation viz. radon exhalation rate and ventilation rate were measured as a part of this study. Validation experiments were performed by measuring radon concentration at different locations of test room using active (continuous radon monitor) and passive (pin-hole dosimeters) techniques. Modeling predictions have been found to be reasonably matching with the measurement results. The validated model can be used to understand and study factors affecting indoor radon distribution for more realistic indoor environment.

CFD based simulation of thoron ((220)Rn) concentration in a delay chamber for mitigation application.

The release of (220)Rn gas (conventionally referred to as thoron) is an issue of concern from the radiological point of view for occupational environments pertaining to the thorium fuel cycle. Studies for understanding its release and developing systems to control it are crucial for exposure control research. A thorough study of the "Delay Volume Technique" for mitigation of (220)Rn has been carried out. Experiments have been carried out with (220)Rn source and associated measurement system in a cubical chamber (delay chamber) of 0.5 m(3) volume. For different flow conditions and inlet-outlet positions, (220)Rn transmission factor has been obtained. Computational Fluid Dynamics (CFD) technique has been employed for these experimental conditions and the simulated transmission factors have been compared. The results show that the flow and the position of the inlet and outlet play an imperative role in the transportation, mixing and subsequent mitigation of thoron inside the chamber. Predictive capability of CFD technique for such delay volume experiments has been validated in this work. A comparison has been made with uniform mixing model and it is found that the results of simulation differ appreciably from that of uniform mixing model at the tested flow regime.

Management of perianal abscess and fistula-in-ano in children.

INTRODUCTION: Perianal abscess (PA) and fistula-in-ano (FIA) are common acquired anorectal disorders in children, but their management is still controversial. This study was performed to evaluate our experience with the treatment of PA and FIA in children of different age groups. MATERIAL AND METHODS: A retrospective study was conducted of children below 16 years of age treated for PA/FIA in a pediatric surgery center between January 2002 and April 2006. The standard treatment for PA was incision and drainage (I&D). Judicious probing for fistulae was only performed in recurrent abscess or if a discharge of pus was identified from the anal verge at surgery. Fistulotomy was routinely performed in low fistulae not associated with inflammatory bowel disease (IBD). IBD associated fistulae were treated with topical tacrolimus in the absence of deep seated infection. Patients were divided into 3 age groups: <2 years, 2-8 years and >8 years. Mode of treatment, microbial organisms, recurrence, associated FIA and association with IBD were recorded. The median follow-up period was 6 months (8 weeks-3 years). Fisher's exact test was used for the analysis of categorical variables. RESULTS: A total of 78 (39 [<2 years]; 17 [2-8 years]; 22 [>8 years]) patients were treated for PA/FIA during the four year period. In children aged <2 years, 33 (85%) had I&D of PA and the other 6 (15%) had fistulotomy. Recurrence was seen in 9 (23%) children, of which 3 (8%) had FIA. In children aged 2-8 years, 13 (76%) had PA and 4 (24%) had a FIA and there were no recurrences. In children >8 years, 12 (55%) had I&D, 1 (4%) had a fistulotomy and 9 (41%) were treated non-surgically. Six of 7 patients with IBD associated FIA were treated successfully with topical tacrolimus. The recurrence rate after primary surgery was significantly higher for <2 years and >8 years age groups compared to the 2-8 years age group. The incidence of FIA identified either at primary operation or during exploration for recurrence was highest (50%) in >8 years age group and lowest (21%) in the <2 years age group. Lactose fermenting coliforms were the most common organisms isolated from pus. The presence of intestinal organisms in pus was associated with significantly higher recurrence rates in children aged <2 years. CONCLUSIONS: Surgery for PA/FIA in children aged <2 years resulted in low recurrence rates and should be considered as the primary treatment. Topical tacrolimus was found to be an effective treatment for IBD associated FIA.

Automated vitrector-assisted iridectomy and phacoemulsification in eyes with coexisting cataract and adherent leucomas.

PURPOSE: To describe a surgical technique as an alternative to allograft corneal transplantation for management of cases with cataract and corneal opacity. METHODS: Seven eyes of seven patients with adherent leucomas and cataract underwent phacoemulsification with intraocular lens (IOL) implantation. An automated vitrector was used to release the adherent leucoma and create an optical iridectomy at the start of surgery. Phacoemulsification with IOL implantation was performed in all eyes. The release of the iris adherence along with creation of an optical iridectomy improved visualization during phacoemulsification. RESULTS: Phacoemulsification and IOL implantation could be performed successfully in all seven eyes. The median best-corrected visual acuity (BCVA) improved from 1/60 (range: (light perception) 6/36) preoperatively to 6/18 (range: 6/36-6/12) at last follow-up (average: 41 days). CONCLUSIONS: This surgical technique is a viable option in cases with partial corneal opacification with coexisting cataract.

Pattern of ocular tumors in the eastern region of Nepal.

BACKGROUND: ocular tumors are commonly encountered in ophthalmic practice. OBJECTIVE: to study the clinical pattern of ocular tumors in the eastern region of Nepal. MATERIALS AND METHODS: the hospital records of patients with ocular tumors treated at B P Koirala Institute of Health Sciences in the eastern region of Nepal over a period of 5 years (April 2003 - March 2008) were studied retrospectively. RESULTS: of 115 consecutive patients with ocular tumors, 40 (34.75%) were below the age of 21 years, 41 (35.65%) were in the age group of 21-50 years and 34 (29.56%) of age above 50 years. There were 48 (41.73%) and 67 (58.26%) patients with benign and malignant tumors respectively. The common benign tumors were conjunctival papilloma, dermoid cysts, nevus, cystic lesions and hemangioma. Among the malignant tumors, basal cell carcinoma was the commonest (22.38%). Retinoblastoma was the most common ocular malignant tumor in the pediatric age group (88.8%). Basal cell carcinoma was the commonest eyelid malignancy (53.57%). CONCLUSION: conjunctival papilloma, dermoid cysts, nevus, cystic lesions and hemangioma are common benign ocular tumors, whereas basal cell carcinoma and retinoblastoma are the commonest ocular malignancies in adults and children respectively.

A nontransfusional perioperative management regimen for patients with sickle cell disease undergoing laparoscopic cholecystectomy.

BACKGROUND: Patients with sickle cell disease (SCD) are at increased risk for cholelithiasis. Laparoscopic cholecystectomy is the most frequent general surgical operation performed for this group of patients. Acute chest syndrome (ACS) is the most common cause of postoperative death among SCD patients. This study aimed to evaluate the impact of a novel perioperative management regimen involving prophylactic continuous positive airways pressure (CPAP) ventilation and avoidance of preoperative blood transfusion on postoperative SCD-related complications after laparoscopic cholecystectomy. METHODS: A retrospective study included all SCD patients who underwent laparoscopic cholecystectomy since 1997 at our institution. Medical notes were analyzed to assess the rates of postoperative complications in relation to the severity of SCD. RESULTS: A total of 13 patients were identified. There were no recorded episodes of acute painful crises and only one patient experienced an episode of ACS requiring protracted CPAP. CONCLUSION: Laparoscopic cholecystectomy can be safely performed for SCD patients without prior blood transfusion. A defined perioperative regimen including the use of routine postoperative prophylactic CPAP for these patients helps to reduce SCD-related postoperative complications such as ACS and painful vaso-occlusive crises.

Sentinel node biopsy can replace four-node-sampling in staging early breast cancer.

AIM: Four-node axillary sampling for breast cancer is an established method of staging the axilla in the United Kingdom. We report the sensitivity of sentinel node (SN) biopsy and compare it with that of four-node sampling. METHODS: SN identification was attempted in 234 consecutive patients with unifocal breast cancers up to 25 mm in diameter on pre-operative ultrasound. A combination of isotope-labelled nanocolloid and patent blue dye techniques were used and SN were identified in 221 (94.5%). All patients underwent back-up four-node sampling and those with positive sentinel nodes on frozen section (FS) underwent immediate full axillary clearance. RESULTS: Among those patients who had SN successfully identified, an average of 1.38 SN were identified per patient. Histological examination of the SN alone would have identified all node-positive patients that the four-node sample identified. CONCLUSION: In patients who have SN identified, four-node axillary sampling does not provide any additional information.

Ultrasound biomicroscopy in lens "coloboma".

PURPOSE: To study the morphology of the Lens "Coloboma" using the technique of ultrasound biomicroscopy. METHODS: We used the Paradigm 40 Ultrasound biomicroscope to study the morphology of the lens "Coloboma". RESULTS: Ultrasound biomicroscopy of the lens "Coloboma" revealed a greatly increased sphericity of the lens and the deficiency of zonules in the "colobomatous" area. CONCLUSIONS: Ultrasound biomicroscopy has helped in elucidating the pathology of the lens "Coloboma".

Core biopsy versus FNAC for palpable breast cancers. Is image guidance necessary?

The aim of this study was to assess the efficacy of free-hand percutaneous core biopsy (FHCB) and to determine the role of fine needle aspiration cytology (FNAC) as diagnostic tools for palpable radiologically-suspicious breast lumps. This retrospective study was based on reviewing the clinical records of all patients diagnosed as having breast cancer between January 1999 and December 2000 and patients who had benign lesions, but suspicious breast imaging at triple assessment. Absolute sensitivity of FHCB for diagnosing cancer in palpable lesions was 98.7% compared with 51.3% for FNAC. The difference in the sensitivity of FHCB and FNAC was statistically significant (P<0.005, Wilcoxon matched pair test). Since 94.8% of radiologically-suspicious lumps were shown to be cancers, we advocate FHCB for all patients presenting with radiologically suspicious palpable lumps to our breast clinic. We also conclude that the sensitivity of FHCB for the diagnosis of malignancy in palpable radiologically-suspicious breast lesions is so high that image-guidance is unnecessary.

Image-guided surgery for anal fistula in a 0.5T interventional MRI unit.

PURPOSE: To determine whether MR-guided anorectal surgery is feasible, and to develop techniques for MR-guided anal fistula surgery. MATERIALS AND METHODS: Six patients with pilonidal sinus (PNS), and 21 with suspected anal fistulae were operated on in the GE Signa SPIO 0.5T interventional MRI unit. Procedures were performed with magnet-safe Lockhart-Mummery fistula probes. Preprocedural and intra-operative MRI (IOMRI) techniques were used to identify the extent of the fistula tracts and septic foci, and to ensure the adequacy of the surgical procedure. RESULTS: IOMRI demonstrated the PNS lesions and the adequacy of excision. Imaging failed to demonstrate a fistula in two patients, as confirmed by surgical examination. No images were obtained in one patient due to his size (weight in excess of 100 kg). In 18 patients a fistula tract or abscess was demonstrated and IOMRI was used to assess the adequacy of the surgical procedure. In three patients this demonstrated incomplete drainage of septic foci, which was not obvious on inspection of the surgical field. We believe that in these patients IOMRI prevented an incomplete procedure and the potential requirement for a second operation. Further surgery was performed to rectify this situation. The fistula tract was laid open in 13 patients, and a Seton drain was inserted in five. CONCLUSION: MRI-guided surgery for anal fistula is feasible. IOMRI demonstrates the exact anatomy of the tracts and abscesses, and confirms that all have been adequately treated. We believe it may become particularly useful in surgery for recurrent and complex anal fistulae, and may lead to fewer recurrences.

Laser in situ keratomileusis for residual myopia after primary LASIK.

PURPOSE: To analyze the results of secondary laser in situ keratomileusis (LASIK) for residual myopia after primary LASIK. SETTING: Dr. Agarwal's Eye Hospital, Chennai, India. METHODS: A retrospective study of 50 eyes of 29 patients who had a secondary LASIK procedure was carried out. After a mean follow-up of 5.84 months +/- 3.24 (SD) after the primary procedure, the mean myopic residual refraction was -4.30 +/- 1.83 diopters (D). In 10 eyes, the primary corneal flap was lifted by blunt dissection. In 40 eyes, the flap was made with a second cut. The secondary LASIK was performed using the Chiron Technolas Keracor 217 excimer laser and the Automated Corneal Shaper microkeratome (Bausch & Lomb). RESULTS: The mean follow-up was 16.58 +/- 3.06 months. At 12 months, the mean spherical equivalent was -0.45 +/- 0.68 D (P <.05). Thirty-one eyes were emmetropic, 13 eyes were within +/-1.00 D of emmetropia, and 5 eyes were within +/-2.00 D. The mean uncorrected visual acuity improved from 20/80 (range 20/60 to 20/200) to 20/40 (range 20/20 to 20/200) (P <.005). Seventeen eyes gained 1 line of best spectacle-corrected visual acuity; 1 eye lost 1 line because of a decentered ablation with an induced postoperative astigmatism of -3.50 D cylinder. No sight-threatening complications such as a free cap, flap irregularity, corneal ectasia, or retinal complication occurred postoperatively. Epithelial ingrowth developed in 5 eyes and corneal thinning, in 1 eye. Three eyes had night glare. CONCLUSION: Secondary LASIK was a safe, stable, and effective method for the treatment of residual myopia after primary LASIK.