Unraveling two distinct polymorph transition mechanisms in one n-type single crystal for dynamic electronics

Cooperativity is used by living systems to circumvent energetic and entropic barriers to yield highly efficient molecular processes. Cooperative structural transitions involve the concerted displacement of molecules in a crystalline material, as opposed to typical molecule-by-molecule nucleation and growth mechanisms which often break single crystallinity. Cooperative transitions have acquired much attention for low transition barriers, ultrafast kinetics, and structural reversibility. However, cooperative transitions are rare in molecular crystals and their origin is poorly understood. Crystals of 2-dimensional quinoidal terthiophene (2DQTT-o-B), a high-performance n-type organic semiconductor, demonstrate two distinct thermally activated phase transitions following these mechanisms. Here we show reorientation of the alkyl side chains triggers cooperative behavior, tilting the molecules like dominos. Whereas, nucleation and growth transition is coincident with increasing alkyl chain disorder and driven by forming a biradical state. We establish alkyl chain engineering as integral to rationally controlling these polymorphic behaviors for novel electronic applications.

Not All Aggregates Are Made the Same: Distinct Structures of Solution Aggregates Drastically Modulate Assembly Pathways, Morphology, and Electronic Properties of Conjugated Polymers

Tuning structures of solution-state aggregation and aggregation-mediated assembly pathways of conjugated polymers is crucial for optimizing their solid-state morphology and charge-transport property. However, it remains challenging to unravel and control the exact structures of solution aggregates, let alone to modulate assembly pathways in a controlled fashion. Herein, aggregate structures of an isoindigo-bithiophene-based polymer (PII-2T) are modulated by tuning selectivity of the solvent toward the side chain versus the backbone, which leads to three distinct assembly pathways: direct crystallization from side-chain-associated amorphous aggregates, chiral liquid crystal (LC)-mediated assembly from semicrystalline aggregates with side-chain and backbone stacking, and random agglomeration from backbone-stacked semicrystalline aggregates. Importantly, it is demonstrated that the amorphous solution aggregates, compared with semicrystalline ones, lead to significantly improved alignment and reduced paracrystalline disorder in the solid state due to direct crystallization during the meniscus-guided coating process. Alignment quantified by the dichroic ratio is enhanced by up to 14-fold, and the charge-carrier mobility increases by a maximum of 20-fold in films printed from amorphous aggregates compared to those from semicrystalline aggregates. This work shows that by tuning the precise structure of solution aggregates, the assembly pathways and the resulting thin-film morphology and device properties can be drastically tuned.

Role of Interfacial Interactions in the Graphene-Directed Assembly of Monolayer Conjugated Polymers

Development of graphene-organic hybrid electronics is one of the most promising directions for next-generation electronic materials. However, it remains challenging to understand the graphene-organic semiconductor interactions right at the interface, which is key to designing hybrid electronics. Herein, we study the influence of graphene on the multiscale morphology of solution-processed monolayers of conjugated polymers (PII-2T, DPP-BTz, DPP2T-TT, and DPP-T-TMS). The strong interaction between graphene and PII-2T was manifested in the high fiber density and high film coverage of monolayer films deposited on graphene compared to plasma SiO2 substrates. The monolayer films on graphene also exhibited a higher relative degree of crystallinity and dichroic ratio or polymer alignment, i.e., higher degree of order. Raman spectroscopy revealed the increased backbone planarity of the conjugated polymers upon deposition on graphene as well as the existence of electronic interaction across the interface. This speculation was further substantiated by the results of photoelectron spectroscopy (XPS and UPS) of PII-2T, which showed a decrease in binding energy of several atomic energy levels, movement of the Fermi level toward HOMO, and an increase in work function, all of which indicate p-doping of the polymer. Our results provide a new level of understanding on graphene-polymer interactions at nanoscopic interfaces and the consequent impact on multiscale morphology, which will aid in the design of efficient graphene-organic hybrid electronics.

Chiral emergence in multistep hierarchical assembly of achiral conjugated polymers

Intimately connected to the rule of life, chirality remains a long-time fascination in biology, chemistry, physics and materials science. Chiral structures, e.g., nucleic acid and cholesteric phase developed from chiral molecules are common in nature and synthetic soft materials. While it was recently discovered that achiral but bent-core mesogens can also form chiral helices, the assembly of chiral microstructures from achiral polymers has rarely been explored. Here, we reveal chiral emergence from achiral conjugated polymers, in which hierarchical helical structures are developed through a multistep assembly pathway. Upon increasing concentration beyond a threshold volume fraction, dispersed polymer nanofibers form lyotropic liquid crystalline (LC) mesophases with complex, chiral morphologies. Combining imaging, X-ray and spectroscopy techniques with molecular simulations, we demonstrate that this structural evolution arises from torsional polymer molecules which induce multiscale helical assembly, progressing from nano- to micron scale helical structures as the solution concentration increases. This study unveils a previously unknown complex state of matter for conjugated polymers that can pave way to a field of chiral (opto)electronics. We anticipate that hierarchical chiral helical structures can profoundly impact how conjugated polymers interact with light, transport charges, and transduce signals from biomolecular interactions and even give rise to properties unimagined before.

Neurological Outcome of Early versus Late Surgery Following Cervical Spinal Cord Injury

Background There are numerous retrospective studies and a few prospective studies to determine the neurologic outcome after early versus late surgical treatment for cervical spinal cord injury. Objective To compare the neurological outcome between early (within 72 hours after injury) and delayed (≥ 72 hours after injury) surgery in patients with cervical spinal injury. Method This is a retrospective analysis of the neurological outcome of early versus late surgery following cervical spinal cord trauma. Patients meeting appropriate inclusion criteria were divided into an early or a late surgical treatment group. The neurologic outcomes and other complications were recorded up to six months of follow-up. Result Overall, there was a significant difference in neurological status at presentation and at follow-up (p < 0.001). However, there was no statistically significant difference between the early versus late surgery groups (p-value 0.261) in terms of neurological outcome. Complications were found to be higher among those undergoing posterior surgical approach (OR = 23.75; 95% CI 2.65, 212.98) than those with anterior or combined approach (p=0.005). However, multivariate analysis of these variables failed to show any statistically significant difference between the two groups. Conclusion The timing of surgery does not alter the neurological outcomes and the development of complications significantly. The American Spinal Cord Injury Association (ASIA) status at the time of presentation is found to be the single most important factor correlating with the neurological outcome.

Drastic Modulation of Molecular Packing and Intrinsic Dissolution Rates by Meniscus-Guided Coating of Extremely Confined Pharmaceutical Thin Films

Nanosizing has emerged as one of the most effective formulation strategies for enhancement of dissolution properties of active pharmaceutical ingredients (APIs). In addition to enhancing the specific area of the dissolving solids, nanosizing can also capture and stabilize the metastable form of the API, which can further enhance the solubility by drastic modulation of surface energies. Herein, we employ meniscus-guided coating to fabricate nanothin films of three APIs that show anticancer properties and are poorly soluble:10-HCPT, SN-38, and amonafide. By modulating the coating speed, we systematically deposited the APIs in films ranging from ∼200 nm thickness to extreme confinement of ∼10 nm (<10 molecular layers). In all three APIs, we observe a general order-to-disorder transition with semicrystalline (10-HCPT and amonafide) or amorphous (SN-38) form of API solids trapped in thin films when the thickness decreases below a critical value of ∼25-30 nm. The existence of a critical thickness highlights the importance of nanoconfinement in tuning molecular packing. In the case of 10-HCPT, we demonstrate that the disordered form of the API occurs largely due to lack of incorporation of water molecules in thinner films below the critical thickness, thereby disrupting the three-dimensional hydrogen-bonded network held by water molecules. We further developed a dissolution model that predicts variation of the intrinsic dissolution rate (IDR) with API film thickness, which also closely matched with experimental results. We achieved drastic improvement in the IDR of ∼240% in 10-HCPT by decreasing film thickness alone. Further leveraging the order-to-disorder transition led to 2570% modulation of the IDR for amonafide. Our work demonstrates, for the first time, opportunities to largely modulate API dissolution by precisely controlling the dimensionality of thin films.

Role of Multivalent Interactions in Dynamic-Template-Directed Assembly of Conjugated Polymers

Dynamic-template-directed assembly is a promising method to enhance molecular ordering and electronic properties of solution-coated polymer semiconductor thin films over a large area. In this work, we establish that multicomponent dynamic templates of complementary chemistries can promote polymer crystallization through cooperative multivalent interactions. We investigate this phenomenon using a combination of templating substrates including a fluoropolymer, a hydrogen-bonded liquid, and an ionic liquid (IL). Template-dependent multiscale morphology is studied by a comprehensive set of characterization techniques to understand how introducing diverse chemical moieties modulates polymer assembly. Our results clearly confirm synergistic effects between components of complementary chemistries constituting the dynamic template. The relative degree of crystallinity is improved by 50-150% for films deposited on multicomponent dynamic templates compared to their neat constituents. In addition, macroscopic alignment is increased significantly (2-5 times) compared to single-component templates. As a result, highly anisotropic charge transport is observed with apparent hole mobilities up to 3.6 cm² V^-1 s^-1. In contrast, such a synergistic effect is not observed when using a multicomponent dynamic template of comparable chemistries (i.e., IL and polymerized IL). We elucidate the origin of this synergistic effect by using attenuated total reflectance Fourier transform infrared spectroscopy and isothermal titration calorimetry. When the dynamic template comprises two or more components interacting with complementary binding sites on the conjugated polymer (CP) (esp. backbone vs side chain), the template-polymer interactions is significantly enhanced compared to the sum of single component contributions. These results provide valuable insights into surface-directed CP crystallization during large-area solution coating. Template dynamics is rarely studied and represents a new opportunity for guiding assembly of soft functional matter.

Repurposing DNA-binding agents as H-bonded organic semiconductors

Organic semiconductors are usually polycyclic aromatic hydrocarbons and their analogs containing heteroatom substitution. Bioinspired materials chemistry of organic electronics promises new charge transport mechanism and specific molecular recognition with biomolecules. We discover organic semiconductors from deoxyribonucleic acid topoisomerase inhibitors, featuring conjugated backbone decorated with hydrogen-bonding moieties distinct from common organic semiconductors. Using ellipticine as a model compound, we find that hydrogen bonds not only guide polymorph assembly, but are also critical to forming efficient charge transport pathways along π-conjugated planes when at a low dihedral angle by shortening the end-to-end distance of adjacent π planes. In the π-π stacking and hydrogen-bonding directions, the intrinsic, short-range hole mobilities reach as high as 6.5 cm2V-1s-1 and 4.2 cm2V-1s-1 measured by microwave conductivity, and the long-range apparent hole mobilities are up to 1.3 × 10-3 cm2V-1s-1 and 0.4 × 10-3 cm2V-1s-1 measured in field-effect transistors. We further demonstrate printed transistor devices and chemical sensors as potential applications.

Tuning conformation, assembly, and charge transport properties of conjugated polymers by printing flow

Intrachain charge transport is unique to conjugated polymers distinct from inorganic and small molecular semiconductors and is key to achieving high-performance organic electronics. Polymer backbone planarity and thin film morphology sensitively modulate intrachain charge transport. However, simple, generic nonsynthetic approaches for tuning backbone planarity and the ensuing multiscale assembly process do not exist. We first demonstrate that printing flow is capable of planarizing the originally twisted polymer backbone to substantially increase the conjugation length. This conformation change leads to a marked morphological transition from chiral, twinned domains to achiral, highly aligned morphology, hence a fourfold increase in charge carrier mobilities. We found a surprising mechanism that flow extinguishes a lyotropic twist-bend mesophase upon backbone planarization, leading to the observed morphology and electronic structure transitions.

Experimental Life-Cycle of Varestrongylus eleguneniensis (Nematoda: Protostrongylidae) in a Captive Reindeer (Rangifer tarandus tarandus) and a Muskox (Ovibos moschatus moschatus)

The life-cycle of a recently described protostrongylid lungworm, Varestrongylus eleguneniensis, which infects caribou, muskoxen, and moose from Arctic and boreal regions of North America, was completed experimentally for the first time. A native North American slug species, Deroceras laeve, was infected with the first-stage larvae (L1) isolated from the feces of wild muskoxen to generate third-stage larvae (L3). These were administered to a captive reindeer calf (250 L3) and an adult captive muskox (380 L3). The prepatent periods for the reindeer and muskox were 56 and 72 days, respectively. Patency lasted for only 19 days in the reindeer, and fecal larval counts were very low (0.09-1.53 larvae per gram of feces). Patency in the muskox was at least 210 days, and likely over 653 days, and the fecal larval counts were higher (0.06-17.8 larvae per gram of feces). This work provides the first experimental completion of the life-cycle of V. eleguneniensis.

Molecular Insights into the Impact of Oxidative Stress on the Quorum-Sensing Regulator Protein LasR

The LasR regulator protein functions at the top of the Pseudomonas aeruginosa quorum-sensing hierarchy and is implicated in promoting bacterial virulence. Of note is recent evidence that this transcription factor may also respond to oxidative stress. Here, all cysteines in LasR were inspected to deduce their redox sensitivity and to probe the connection between stress response and LasR activity using purified LasR and individual LasR domains. Cys(79) in the ligand binding domain of LasR appears to be important for ligand recognition and folding of this domain to potentiate DNA binding but does not seem to be sensitive to oxidative stress when bound to its native ligand. Two cysteines in the DNA binding domain of LasR do form a disulfide bond when treated with hydrogen peroxide, and formation of this Cys(201)-Cys(203) disulfide bond appears to disrupt the DNA binding activity of the transcription factor. Mutagenesis of either of these cysteines leads to expression of a protein that no longer binds DNA. A cell-based reporter assay linking LasR function with β-galactosidase activity gave results consistent with those obtained with purified LasR. This work provides a possible mechanism for oxidative stress response by LasR and indicates that multiple cysteines within the protein may prove to be useful targets for disabling its activity.

Carcinoma of the appendix – A diagnostic challenge

INTRODUCTION Primary tumors of the appendix are rare. They are usually diagnosed after pathologic inspection of the appendix removed for suspected appendicitis. The main presentation is that of an acute appendicitis or as a palpable mass, mainly in the right lower quadrant. It mimics ovarian pathology in female because of close proximity to its anatomical structures. CASE PRESENTATION We report a case of 52 years female who presented to us in casualty with complains of pain abdomen and other findings suggestive of acute appendicitis. In spite of extensive preoperative investigations, the diagnosis was confirmed only after opening the abdomen as giant mucocele of appendix demanding right hemicolectomy as a treatment modality. CONCLUSION Although primary tumors of appendix is rare identity in the arena of surgery, it should be in the corner of thought as a possible diagnosis which require extensive surgery when compared to simple Appendicectomy.DOI: http://dx.doi.org/10.3126/jcmsn.v10i2.12953 Journal of College of Medical Sciences-Nepal, 2014, Vol.10(2); 36-40

Unusual non-enzymatic flavin catalysis enhances understanding of flavoenzymes

Flavin cofactors are central to many biochemical transformations and are typically tightly bound as part of a catalytically active flavoenzyme. This work indicates that naturally occurring flavins can act as stand-alone catalysts to promote the oxidation of biosynthetically inspired heterocycles in aqueous buffers. Flavin activity was compared with that of oxidases important in non-ribosomal peptide synthesis, providing a rare direct comparison between the catalytic efficacy of flavins alone and in the context of a full flavoenzyme. This study suggests that such oxidases are likely to possess an active site base, as oxidase activity was greater than that of flavins alone, particularly for less acidic substrates. These findings offer perspective on the development of robust and catalytically effective, designed miniature flavoenzymes.

Clinical profile, management and early outcome of gall bladder cancer

Objective To evaluate the clinical profile, management and early outcome of patients with gallbladder cancer.Methods This is a single institution based retrospective study of patients with gallbladder cancer who presented at College of Medical Sciences and Teaching Hospital, Bharatpur, Chitwan, Nepal. Patients presenting during one year period from August 2012 to July 2013 were reviewed. Results Twelve cases of Gall Bladder Cancer were reviewed in this series. Out of 12 patients, 9 were females (75%) and 3 were males (25%), showing female preponderance. Most of the patients (75%) were in age group of 51-70 years. Only one patient (8%) was below 50 years of age. Main symptom was pain associated with anorexia, nausea & vomiting. Major signs were palpable mass, hepatomegaly and jaundice. All the cases had association with gall bladder stone. Of the total population, 50%(n=6) underwent extended cholecystectomy and rest of 6 cases were inoperable. Histopathological reports of all the operated cases were adenocarcinoma.Conclusion Prevalence of gall bladder cancer is higher in females in our series. Most of the patients were in fifth to seventh decade of life. Non specific symptoms like abdominal pain nausea and vomiting were the predominant symptoms. Only 50% of the cases were operable. So we have to do early screening by USG abdomen and CT scan to diagnose the disease earlier.   Journal of College of Medical Sciences-Nepal, 2013, Vol-9, No-3, 12-16  

Surgical outcome and clinical profile of emergency versus elective cases of colorectal cancer in College of Medical Sciences, Nepal

Background: Patients who undergo emergency colorectal cancer surgery has poor outcome compared to elective surgery, both in terms of morbidity and mortality. Approximately 15 to 30% of colorectal cancers present as an emergency, most often as obstruction or perforation. Objective: To compare surgical outcome and clinical profiles of emergency and elective cases for colorectal cancer. Methods: Retrospective analysis of 34 cases who underwent surgery for colorectal cancer between December 2011 to January 2013was carried out and their surgical outcomes, clinical presentation, demographic profile were analyzed. Results: The total numbers of patients included in this study were 34. Out of which 52.94 %( n=18) were emergency cases and 47.05 %( n=16) were elective. Male female ratio was 3:1 in emergency cases and 2.6:1 in elective cases. Per rectal bleeding (56%) and altered bowel habit (31.25%) was predominant clinical presentation in elective cases whereas intestinal obstruction (55.55%) and peritonitis (22.22%) were predominant clinical presentation in emergency cases. In emergency cases most of the tumors were located in left side (77.77%) and in elective cases rectum was common site (37.5%). Left hemicolectomy was the commonest surgery performed (72.22%) in emergency set up. In elective cases, right hemicolectomy, left hemicolectomy, APR and LAR was done in 31.25%, 31.25%, 25% and 25% cases respectively. In the emergency group 11.11% (n=2) developed enterocutaneous fistula and early mortality within 30 days was observed in 5% (n=1) of emergency cases only. Conclusion: In emergency conditions, colorectal cancer presented with intestinal obstruction where as elective cases presented with per rectal bleeding and altered bowel habits. Compared with the elective patients, the emergency patients had higher rate of morbidity and mortality. Because of higher incidence of colorectal cancer in our institution, in all emergency cases who presents with features of intestinal obstruction and peritonitis, we have to rule out colorectal cancer especially if the patients are elderly. Therefore, we should encourage screening programme for early detection of colorectal cancers for better outcome of surgery. Journal of College of Medical Sciences-Nepal, 2013, Vol-9, No-2, 25-30 DOI: http://dx.doi.org/10.3126/jcmsn.v9i2.9684

Outcome of manual hemorrhoidopexy in the management of hemorrhoids

Background: Manual hemorrhoidopexy is a new technique of treating second degree hemorrhoids. In contrast to the conventional resectional techniques (Milligan-Morgan), manual hemorrhoidopexy is a novel technique as described by T Carlo. It does not involve excision but plication with fixation of the prolapsing hemorrhoid. Objective: To study the outcome of manual hemorrhoidopexy and to compare manual hemorrhoidopexy with the traditional hemorrhoidectomy. Methods: This is a prospective study conducted over 16 months (January 2012 to April 2013) in the College of Medical Sciences Teaching Hospital (COMS-TH), Bharatpur, Chitwan, Department of Surgery. The patients who presented with third degree internal-hemorrhoids on a random basis, and underwent either conventional hemorrhoidectomy (Group A) or Manual hemorrhoidopexy (Group B) by senior consultant surgeons were included. The patients who had external hemorrhoids in addition to internal were excluded. Preoperative, intraoperative, and postoperative characteristics were evaluated. Results: Twenty five patients with median age group 42.5 years underwent conventional (Milligan-Morgan) hemorrhoidectomy (Group A) and 25 patients with mean age of 40.1 years underwent manual hemorrhoidopexy (Group B). Male patients were predominant in both groups. The patients in group A had more postoperative pain as compared to group B (as assessed by the visual analogue scale and requirement of post-operative analgesic) and this was statistically significant (p<0.001). There was no significant difference among the other post-operative urinary retention. Twelve percent (n=3) patients in group A had post-operative bleeding and only 4% (n=1) in group B which was statistically significant (p<0.001). Mean duration of hospital stay in group A was 2.5 days as compared to 1.5 day in group B. Median follow up in both the study group was 3 (2-4) months. Conclusion: Manual hemorrhoidopexy has comparable outcomes in term of postoperative analgesic requirement, and post operative complications. Journal of College of Medical Sciences-Nepal, 2013, Vol-9, No-2, 15-19 DOI: http://dx.doi.org/10.3126/jcmsn.v9i2.9682

Retrorectal tumors: report of two cases

Retrorectal tumor is uncommon identity presenting with nonspecific sign and symptoms making difficulty in diagnosis. Benign tumors are more common than malignant. The lesion may be malignant or progress to malignancy from benign state. Retrorectal masses in young women may continue to grow and result in dystocia. Cystic lesions are also at risk of becoming infected, which renders subsequent excision more difficult and increase the risk of recurrence. Cross-sectional imaging is required to determine the extent of resection and the appropriate surgical approach. Surgical removal leads to favorable outcomes for patients with benign purely cystic retrorectal tumors. We report two such benign rectal lesions. ] Journal of College of Medical Sciences-Nepal, 2012, Vol-8, No-4, 46-50 DOI: http://dx.doi.org/10.3126/jcmsn.v8i4.8701  

Caroli's Disease: A case report

Caroli's disease (CD) is a rare congenital abnormality characterized by dilatation of intra-hepatic bile ducts, recurrent cholangitis, formation of calculi inside these ducts with normal extra hepatic ducts and higher risk for cholangiocarcinoma. Association of this disease with congenital hepatic fibrosis is named as Caroli's syndrome. We reported 30 years old women with recurrent epigastric pain for 2 years with normal Liver function Test however involving both lobes of liver who developed cholangiocarcinoma approximately 6 months later. Journal of College of Medical Sciences-Nepal, 2012, Vol-8, No-3, 51-54 DOI: http://dx.doi.org/10.3126/jcmsn.v8i3.8685

A lethal chest injury following rhinoceros attack– a case report

Injuries following wild animal encounters continue to be a major public health problem. Majority of such injuries are minor, however, many injuries remain undocumented. Many victim die, primarily in third-world countries, before receiving adequate medical care. Penetrating injuries to the chest following the attack by the wild animals, though rare, present a challenging problem. Though a great number of papers have been published regarding the injuries following encounter with animals, least are the lethal injuries occuring in the thoracic region and the survival out of these grave injury is very minimum. We herein present the least possible surviving case with lethal penetrating injury of the chest and left lung following the goring by the rhinoceros. Journal of College of Medical Sciences-Nepal,2012,Vol-8,No-1, 52-55 DOI: http://dx.doi.org/10.3126/jcmsn.v8i1.6827

Use of double-balloon catheter in the management of epistaxis: a boon for the periphery

BACKGROUND

Epistaxis is one of the most commonly encountered emergencies in ENT practise. It has been reported that almost 60% of general population experience epistaxis of small or large quantity in his /her lifetime(1).

OBJECTIVE

The objective of this study was to compare the outcome of double balloon catheter to normal packing method for epistaxis.

MATERIALS AND METHODS

An interventional study of 30 patients admitted in Kathmandu Medical College, Sinamangal, Kathmandu, Nepal from Baisak 2065 to Chaitra 2066 with bleeding from the nose were taken into study. These patients were analysed on the basis of duration of hospital stay, any related cause for epistaxis, modalities of treatment, success of balloon catheter etc.

RESULT

Results with double-balloon catheter showed less hospital stay and better compliance by the patient.

CONCLUSION

This study highlights that double-balloon catheter has a higher chance of acceptance by the patient and is better in the treatment of epistaxis. This method can be undertaken without anaesthetic assistance thus it is very feasible even in the most remote areas of our nation.

Allergic fungal rhinosinusitis in chronic rhinosinusitis

BACKGROUND

Rhinosinusitis is the inflammation of nasal and paranasal sinus mucosa and is associated with mucosal alteration ranging from inflammatory thickening or gross nasal polyp formation.The main objective of this study is to determine the prevalence of allergic fungal rhino sinusitis among the patients having chronic rhino sinusitis with or without polyps who under goes functional endoscopic sinus surgery.

METHODS

The patient with chronic rhinosinusitis with or without polyp who FESS were studied. Surgical specimens were sent for mycology and histopathological analysis for identification of fungus.

RESULTS

Headache 41(82%) and nasal block 45(90%) were the commonest clinical presentation. Out of 50 patients, fungal elements were detected by KOH in 8(16%) of cases and histopathological examination in 11(22%) of cases.

CONCLUSIONS

Allergic Fungal Rhinosinusitisis a common disorder in patients with chronic rhinosinusitis, it need different specific tests for the diagnosis, a more specific diagnostic tests are fungus culture, and IgE to fungal antigen and skin test are needed for definite diagnosis.

Diagnostic accuracy of fine needle aspiration cytology in thyroid swellings

BACKGROUND

Proper management of the disease depends upon accurate diagnosis. Fine Needle Aspiration Cytology has become the investigation of choice because of its high accuracy, simplicity, minimal-invasiveness, quick result and reliability.

METHODS

All the patients with thyroid disease, irrespective of age and gender, who underwent thyroid were studied. These patients had their fine needle aspiration Cytology was done in our centre. Detailed history, physical examination, routine investigations, radiological investigations (including CT scans when needed), hormonal assay, (T3, T4, TSH ), ultrasound of neck and FNAC were done. Pre- operative fine needle aspiration results were compared with histopathology results of operated specimen and then analyzed statistically to assess the sensitivity, specificity and accuracy of the result.

RESULTS

There were total of 51 patients. Age ranges from 21 to 62 years. The study duration was from May 2006 to February 2011. Out of 51 patients, 82.35% (n=42) were females and 17.64% (n=9) were males. In 43 patients, FNAC showed benign lesions, of which 40 were true negative (TN) and three false negative (FN), which on histopathology reported malignancy. Remaining eight cases were diagnosed as malignancy on histopathology of which seven cases were true positive (TP), one case of false positive (FP) was detected in our study. Over all Sensitivity was 70% and specificity was 97.5% and accuracy of FNAC was 92.1%.

CONCLUSIONS

FNAC should be performed in all cases of thyroid nodules because of its high sensitivity and specificity to differentiate benign from malignant lesions and counsel the patient as well as plan surgery accordingly. Expenditure, time and the hassle of revision surgery is minimized by the pre operative FNAC report.

Observation of hearing loss in patients with chronic suppurative otitis media tubotympanic type

BACKGROUND

It is acknowledged that size and site of tympanic membrane perforation is proportional to degree of hearing loss but there are many studies which suggests otherwise. Persistent ear discharge is also supposed to deteriorate hearing level with passage of time. This study is carried out to find out the relation between size and site of tympanic membrane perforation and duration of ear discharge on hearing loss.

OBJECTIVES

The objective of this study is to study the effect of size and site of tympanic membrane perforation and duration of ear discharge on hearing loss.

METHODS AND MATERIALS

This is a cross-sectional prospective study conducted at Kathmandu Medical College, department of ear nose and throat from January till July 2009. One hundred patients aged between 8 to 60 years with pars-tensa perforations were included in the study. Detail clinical examination and history was carried out followed by hearing evaluation by audiometry was done in all cases. All the data is collected, statistical analysis is done using SPSS program and documented for study.

RESULTS

One hundred patients with 119 perforated tympanic membrane, age ranged between 8 to 60 years, 44 males and 56 females were studied. Bilateral tympanic membrane perforation were seen in 19 patients, right sided perforation in 39 and left sided in 42 patients respectively. Large central perforation involving all four quadrants was the most common otologic findings seen in 72 ears (60.50%) whereas perforation in posterosuperior quadrant was the least common finding seen in 3 patients (2.52%). Significant relation is observed between site of perforation and degree of hearing loss; posterior placed perforations seem to have larger hearing loss. Ninety-five perforations (79.83%) showed more loss in low frequencies with larger air bone gap at low frequencies. The longer the duration of ear discharge, the more the hearing loss.

CONCLUSION

The larger the perforation, the greater the decibel loss in sound perception. The location of perforation on the tympanic membrane and the duration of ear discharge have significant effect on the magnitude of hearing loss.

Computed tomographic assessment of lateral lamella of cribriform plate and comparison of depth of olfactory fossa

INTRODUCTION

Endoscopic sinus surgery is an upcoming branch in rhinological practice but with some major risks since it has to play around the skull base area. Lateral lamella of cribriform plate is the thinnest area of the skull base. Thus this study is undertaken to evaluate the height of lateral lamella of cribriform plate and the depth of olfactory fossae by the help of computed tomographic images.

METHODS

Computed tomographic study of 50 patients was done in Advanced Imaging and Diagnostic center, Kathmandu Medical College. Coronal sections at the centre of infra-orbital foramina were taken as reference slide. The height of cribriform plate point was subtracted from the height of medial ethmoidal roof point to measure the length of lateral lamella of cribriform plates on both sides.

RESULTS

The median height of LLCP in 100 slides was 2.8 mm. LLCP height was 0 to 3.9 mm in 86 slides, 4 to 7 mm in 12 slides and greater than 7mm in 2 slides. The LLCP length was greater in right side in 28 (56%) patients and was greater in left side in 19 (38%) patients. It was equal in both sides in only three patients (6%).

CONCLUSIONS

As regards the length of LLCP; 0 to 3.9 mm length was most common. The olfactory fossa depth was more in the right side compared to the left side. Thus, right side is more vulnerable to injury during surgery. Thus adequate caution has to be exercised by the rhinological surgeon during endoscopic sinus surgery.

Comparison of sub mucosal diathermy and partial resection of Inferior turbinate in the treatment of symptomatic nasal valve blockage

OBJECTIVES

to evaluate the efficacy of sub mucosal diathermy (SMD) and partial resection of inferior turbinate (PRIT) in the treatment of symptomatic enlarged inferior turbinates.

STUDY DESIGN

prospective.

METHODS

Forty patients of age group 18 -56 yrs with symptomatic enlarged inferior turbinates had given choices for SMD and PRIT. All the patients had history of failed medical treatment.

RESULTS

Each twenty patients underwent SMD (group I), PRIT (group II), five pt of gr. I had to have anterior nasal packing after surgery for bleeding. Three pt complained of excessive rhinorrhoea for first 2 weeks while 3 pt of Group 1 complained of nasal blockage for 1 week even after intervention. In group 2, 5 pt had to have re-anterior nasal packing after pack removal. Both groups followed up for 6 months. Nine patients were lost in follow up, so excluded from the study. Following 6 months of follow up, 6 patient of gr. I had recurrence with nasal blockage and in gr. II none had recurrence.

CONCLUSION

PRIT is better than SMD in long course; nevertheless it should be reserved for failed SMD, not as a primary option.

Comparison of chemical cautery (AgNo3) and steroid spray against SMD (submucosal diathermy) in the treatment of symptomatic inferior turbinate hypertrophy (ITH)

OBJECTIVE

To compare the efficacy of chemical cautery (AgNo3) and steroid nasal spray against SMD (submucosal diathermy) in the treatment of symptomatic Inferior Turbinate Hypertrophy (ITH).

MATERIALS AND METHODS

Patients attending OPD in the department of ENT &HNS at KMCTH with symptomatic Inferior turbinate Hypertrophy were taken with their approval included for the study. Patients were divided into 2 Groups: in the first Group 25 patients were included and treated with chemical cautery (AgNo3) under Local Anaesthesia (LA), followed by steroid nasal spray for 3 months; in the second Group 25 patients were included and were treated with SMD (submucosal diathermy) under General Anaesthesia (GA).They all had history of use of topical nasal decongestant for different time period. Patients were followed up for 6 months.

RESULTS

In Group 1, 16 patients complain of burning sensation for first week and 8 patients complain of continuous nasal blockage for 6 weeks.1 patient complain about inosmia for 2 weeks. In Group 2, nasal pain was complained by 17 patient for 2 weeks. 3 patients complain of persistent nasal blockage for 4 weeks. 3 patients complain of anosmia for 4 weeks. After completion of 6 months in Group 1, 20 patient has recurrent nasal blockage, whereas in Group 2, 10 patient has recurrent nasal blockage. Besides these, other symptoms noticed during initial phase did not appear.

CONCLUSION

Chemical cautery (AgNo3) and steroid nasal spray is easy to follow, has less complication ,but failure rate is high, whereas SMD is procedure with less failure rate, but has to carried out under GA and has more discomfort postoperatively. For symptomatic inferior turbinate hypertrophy, where topical nasal decongestant has little role SMD is the choice of treatment for longer relief.

Surgical management of sinus tympani cholesteatoma

OBJECTIVE

the aim of this study is to describe the extension of unsafe middle ear disease in the sinus tympani and to review the methods of surgical access to remove the disease from this area.

METHODS

Of the 164 operated ears with unsafe chronic suppurative otitis media 64(39%) ears had variable disease extension into the sinus tympani and were included in the study. Sixty two ears underwent canal wall down (CWD) procedure while remaining two underwent tympanoplasty with bone work.

RESULT

Five operated ears had deeper extension of the disease into the sinus tympani. And despite of different maneuver the complete removal of the disease could not be confirmed. Six ears (9.4%) had recidivism.

CONCLUSION

The study emphasizes on the greater incidence of this disease extension into this difficult anatomical area and their complete removal may not be always possible. But one should require thorough knowledge and surgical expertise to work in this difficult area of posterior mesotympanum.

Intraoperative Findings during Canal Wall Down Mastoidectomy in Children

Objective: The main objective of this study is to assess the intraoperative finding during canal wall down mastoidectomy in paediatric patients undergoing surgery for unsafe type of chronic suppurative otitis media (CSOM) attending ENT OPD of Kathmandu Medical College. Materials and Methods: Fifty patients of age group 4 to 13 years who were suffering from unsafe type of CSOM with or without cholesteatoma were taken for the study. The study period was two years from April 2007 to March 2009. The operative findings like extent of cholesteatoma in different location of middle ear cleft, mastoid bony landmarks, and ossicular chain condition and otogenic complication were identified during canal wall down mastoidectomy. Result: Of the 50 patients 32 (64%) were boys and 18(36%) were girls. The age ranged from 4 years to 13 years. Majority of patients had cholesteatoma with granulation diseases (72%) followed by granulation diseases (16%). Involvement of disease in attic, aditus, antrum and mesotympanum were found to be high in majority of cases (82%) with high percentage of necrosis of incus (56%). Conclusion: The primary disease found in patients undergoing canal wall down mastoidectomy (CWDM) was cholesteatoma combined with granulation in72%, granulation in 16% and cholesteatoma in12%. Key words: Canal Wall Down; ENT; Mastoidectomy; Chronic Suppurative Otitis Media (CSOM) DOI: http://dx.doi.org/10.3126/jnps.v31i3.5357 J Nep Paedtr Soc 2011;31(3):184-187