Characterization of laser-induced shock waves generated during infrared laser ablation of copper by the optical beam deflection method.

The shock waves generated during laser ablation of a copper target are investigated using the optical beam deflection method. The fluence of nanosecond pulsed infrared laser beam was in the range of 15-700J/cm2. The density jumps related with the influx of the shock wave at two interaction points were detected with the help of He-Ne laser probes. In general, a supersonic shock wave is produced, which propagates through air and gradually decays into an acoustic wave. Experiments were carried out to study the impact of laser fluence and propagation distance on the shock wave velocity and pressure. The shock wave velocity varies with laser fluence as v∝Fl0.3 and with propagation distance as v∝d-1.5. These results are compared with the predictions of the theoretical models. In the investigated fluence range, shock wave pressure rises by an order of magnitude (∼1-10MPa). We demonstrated that shock wave pressure and ablated mass can be related, yielding mass-specific shock wave pressure that increases linearly with laser fluence. We have also noticed the shock-wave-induced probe beam focusing under certain conditions, which indicates that the shock wave modifies the refractive index of the compressed layer of air. The reported results are useful for the fundamental understanding and pave the way for new applications of laser-induced shock waves.

Intestinal adaptation in fluid restricted cardiac failure following extensive bowel resection.

Acute mesenteric ischemia (AMI) is an emergency associated with a high mortality rate. A high index of clinical suspicion, prompt diagnosis and treatment is necessary to improve the patient outcome. The principle of damage control surgery should be adopted in the management of critically ill surgical patients with AMI. Strategic planning by resecting the ischemic bowel, physiological restoration and planned reassessment of remnant bowel with a definitive procedure is recommended. The resection of a long segment ischemic bowel may result in morbidity such as that of short bowel syndrome. We report here a case of decompensated cardiac failure in a 56-year-old lady, presented with one-day history of severe acute epigastric pain and abdominal distension. She presented with extensive bowel ischemia involving most of the superior mesenteric artery distribution. Damage control surgery followed by entero-colic anastomosis was performed 48 hours later. The patient recovered with remarkable intestinal adaptation without exhibiting short bowel syndrome symptoms despite the postulated theory of altered intestinal permeability in decompensated cardiac failure.

Machine learning-based texture analysis for differentiation of large adrenal cortical tumours on CT.

AIM: To compare the efficacy of computed tomography (CT) texture analysis and conventional evaluation by radiologists for differentiation between large adrenal adenomas and carcinomas. MATERIALS AND METHODS: Quantitative CT texture analysis was used to evaluate 54 histopathologically proven adrenal masses (mean size=5.9 cm; range=4.1-10 cm) from 54 patients referred to Anderson Cancer Center from January 2002 through April 2014. The patient group included 32 women (mean age at mass evaluation=59 years) and 22 men (mean age at mass evaluation=61 years). Adrenal lesions seen on precontrast and venous-phase CT images were labelled by three different readers, and the labels were used to generate intensity- and geometry-based textural features. The textural features and the attenuation values were considered as input values for a random forest-based classifier. Similarly, the adrenal lesions were classified by two different radiologists based on morphological criteria. Prediction accuracy and interobserver agreement were compared. RESULTS: The textural predictive model achieved a mean accuracy of 82%, whereas the mean accuracy for the radiologists was 68.5% (p<0.0001). The interobserver agreements between the predictive model and radiologists 1 and 2 were 0.44 (p<0.0005; 95% confidence interval [CI]: 0.25-0.62) and 0.47 (p<0.0005; 95% CI: 0.28-0.66), respectively. The Dice similarity coefficient between the readers' image labels was 0.875±0.04. CONCLUSION: CT texture analysis of large adrenal adenomas and carcinomas is likely to improve CT evaluation of adrenal cortical tumours.

Characterization of maize genotypes for genetic diversity on the basis of inter simple sequence repeats.

Genetic diversity in crops is essential to make improvements related to superior germplasms. Implementation of molecular markers to identify suitable genotypes speeds up the breeding progress by enhancing selection efficiency. This study was carried out to probe genetic diversity among 21 maize genotypes using 20 inter simple sequence repeat (ISSR) markers. We identified a total of 190 polymorphic bands with an average of 9.5 alleles per primer. The highest number of polymorphic bands (17) was found using ISSR marker UBC-10, whereas the lowest number of polymorphic bands (4) was found using UBC-809. The coefficient of genetic similarity ranged from 0.888 to 0.118%. The highest similarity was found between accessions 12 (015224) and 9 (015114), whereas the lowest similarity was found between genotypes 20 (EV-5098) and 14 (015030). The polymorphism information content ranged from 0.17 to 0.47. A dendrogram was generated based on Jaccard's distance matrix. The genotypes were found to group into two major clusters that could be further partitioned into two sub-clusters. Genotypes located within the same cluster are genetically more closely related to each other. The present study efficiently identified diverse genotypes that may be used for creating new varieties with distinct characteristics. The identified genotypes could be used as parents for future development of diverse populations.

Measuring myocardial perfusion: the role of PET, MRI and CT.

Recently, focus has changed from anatomical assessment of coronary arteries towards functional testing to evaluate the effect of stenosis on the myocardium before intervention. Besides positron-emission tomography (PET), cardiac MRI (CMR), and cardiac CT are able to measure myocardial perfusion. Myocardial perfusion abnormalities are the first sign of the ischaemic cascade in the development of coronary artery disease (CAD). PET is considered the non-invasive clinical reference standard for absolute quantification of myocardial perfusion. The diagnostic and prognostic value of PET is well-known and is used in routine clinical practice. However, PET uses radioactive tracers and has a lower spatial resolution compared to CMR and CT. CMR and CT are emerging techniques in the field of myocardial perfusion imaging. CMR uses magnetic resonance to obtain images, whereas CT uses x-rays during first-pass of non-ionic and ionic contrast agents, respectively. Absolute quantification with CMR has yet to be established in routine clinical practice, while CT has yet to prove its diagnostic and prognostic value. The upcoming years may change the way we diagnose and treat patients suspected of having CAD with more precise methods for measuring myocardial perfusion. The aim of this comprehensive review is to discuss current and emerging imaging techniques used for myocardial perfusion imaging.

Analysis of genetic traits for drought tolerance in maize.

Fifty-four genotypes of maize were crossed and evaluated in the field during the crop season in February 2012 under both normal and water stress conditions. To identify the major parameters responsible for variation among genotypes, single linkage cluster analysis and principle component analysis (PCA) were carried out. Thirteen characters were studied. The PCA showed that the first six components, with eigen values >1, contributed 82.30% of the variability among the genotypes under normal field irrigation conditions while other PCs (7-13) had eigen values less than 1. Under drought conditions, the first four PCs, with eigen values >1, contributed 64.79% of the variability among genotypes while the other PCs (5-13) had eigen values less than 1. In the absence of water stress, heritability ranged from 68% (sucrose content) to 99% (plant height) and genetic advance ranged between 158.43% for stomatal frequency and 0.87 for biological yield. Under drought conditions, the coefficient of variability (CV) was 1.43-7.79, whereas estimates of heritability ranged between 68% and 99% for sucrose content and leaf area, respectively. The values of genetic advance ranged between 153.41 for stomatal frequency and 0.47 for nitrogen content. CV was 1.52-7.38 under drought conditions. The results indicated that the plant characters studied were under the control of additive genetic effects and suggested that selection should lead to fast genetic improvements. Clusters with superior agronomic types were identified and could be exploited for the transfer of desirable genes to improve the yield potential of the maize crop.

FROM Qutn TO Bt COTTON: DEVELOPMENT, ADOPTION AND PROSPECTS. A REVIEW.

Cotton has unique history of domestication, diversification, and utilization. Globally it is an important cash crop that provides raw material for textile industry. The story of cotton started from human civilization and the climax arrived with the efforts of developing transgenic cotton for various traits. Though conventional breeding brought steady improvement in developing resistance against biotic stresses but recent success story of gene transferfrom Bacillus thuringiensis into cotton showed game changing effects on cotton cultivation. Amongst various families of insecticidal proteins Bt Cry-toxins received more attention because of specificity against receptors on the cell membranes of insect midgut epithelial cells. Rapid Bt cotton adoption by farmers due to its economic and environmental benefits has changed the landscape of cotton cultivation in many countries. But the variable expression of Bt transgene in the newly developed Bt cotton genotypes in tropical environment is questionable. Variability of toxin level in different plant parts at various life stage of plant is an outcome of genotypic interaction with environmental factors. Temporal gene expression of Cry1Ac is also blamed for the epigenetic background in which transgene has been inserted. The presence of genotypes with sub-lethal level of Bt toxin might create resistance in Lepidopteron insects, limiting the use of Bt cotton in future, with the opportunityfor other resistance development strategies to get more attention like gene stacking. Until the farmers get access to more recent technology, best option is to delay the development of resistance by applying Insect Resistance Management (IRM) strategies.

Relationship between genetic parameters in maize (Zea mays) with seedling growth parameters under 40-100% soil moisture conditions.

We estimated the association of genetic parameters with production characters in 64 maize (Zea mays) genotypes in a green house in soil with 40-100% moisture levels (percent of soil moisture capacity). To identify the major parameters that account for variation among the genotypes, we used single linkage cluster analysis and principle component analysis. Ten plant characters were measured. The first two, four, three, and again three components, with eigen values > 1 contributed 75.05, 80.11, 68.67, and 75.87% of the variability among the genotypes under the different moisture levels, i.e., 40, 60, 80, and 100%, respectively. Other principal components (3-10, 5-10, and 4-10) had eigen values less than 1. The highest estimates of heritability were found for root fresh weight, root volume (0.99), and shoot fresh weight (0.995) in 40% soil moisture. Values of genetic advance ranged from 23.4024 for SR at 40% soil moisture to 0.2538 for shoot dry weight in 60% soil moisture. The high magnitude of broad sense heritability provides evidence that these plant characters are under the control of additive genetic effects. This indicates that selection should lead to fast genetic improvement of the material. The superior agronomic types that we identified may be exploited for genetic potential to improve yield potential of the maize crop.

Delayed extensive surgical emphysema after Valsalva manoeuvre post Eustachian tuboplasty.

OBJECTIVE: This paper reports a case of balloon Eustachian tuboplasty with delayed presentation of extensive surgical emphysema. METHODS: This is a clinical case report with a review of literature. RESULTS: Eustachian tube dysfunction is a functional disorder that results in inadequate middle-ear ventilation, causing aural fullness and tinnitus. A 36-year-old male presented with the sudden onset of an isolated, painful, left-sided neck swelling. The patient underwent balloon Eustachian tuboplasty, which was uneventful, but subsequently developed a sudden onset of isolated left-sided neck swelling on the 5th post-operative day during Valsalva manoeuvre. Neck examination revealed extensive crepitus on the left side of the neck. Examination findings were confirmed by imaging. The patient was conservatively managed and subsequently discharged home. CONCLUSION: Balloon Eustachian tuboplasty is a safe procedure; however, extra care must be taken to avoid possible complications. Patients should be counselled against Valsalva manoeuvre and heavy weightlifting. They also should be instructed to sneeze with an open mouth and consider the use of stool softeners.

Bilateral synchronous tonsillar carcinoma: a case series and review of the literature.

We present the first dedicated case series of bilateral synchronous tonsillar carcinoma and discuss the role of bilateral tonsillectomy as a diagnostic tool. The occurrence of multiple head and neck tumours is well recognised; however, reports of bilateral synchronous tonsillar carcinoma are rare. A literature review reveals only 12 cases of bilateral synchronous tonsillar carcinoma described in the international literature in the past 15 years. We present a further three cases confirmed following bilateral tonsillectomy. In conclusion, bilateral tonsillectomy has in many centres been established as a standard diagnostic and therapeutic procedure for patients who have cervical metastases from a head and neck cancer of unknown primary site. It is likely the true incidence of bilateral synchronous tonsillar carcinoma is underestimated and under-reported. We recommend bilateral tonsillectomy for patients with suspected or proven unilateral tonsillar carcinoma as well as those with cervical metastases from unknown primary site.

Introgression of cotton leaf curl virus-resistant genes from Asiatic cotton (Gossypium arboreum) into upland cotton (G. hirsutum).

Cotton is under the constant threat of leaf curl virus, which is a major constraint for successful production of cotton in the Pakistan. A total of 3338 cotton genotypes belonging to different research stations were screened, but none were found to be resistant against the Burewala strain of cotton leaf curl virus (CLCuV). We explored the possibility of transferring virus-resistant genes from Gossypium arboreum (2n = 26) into G. hirsutum (2n = 52) through conventional breeding techniques. Hybridization was done manually between an artificial autotetraploid of G. arboreum and an allotetraploid G. hirsutum, under field conditions. Boll shedding was controlled by application of exogenous hormones, 50 mg/L gibberellic acid and 100 mg/L naphthalene acetic acid. Percentage pollen viability in F(1) hybrids was 1.90% in 2(G. arboreum) x G. hirsutum and 2.38% in G. hirsutum x G. arboreum. Cytological studies of young buds taken from the F(1) hybrids confirmed that they all were sterile. Resistance against CLCuV in the F(1) hybrids was assessed through grafting, using the hybrid plant as the scion; the stock was a virus susceptible cotton plant, tested under field and greenhouse conditions. All F(1) cotton hybrids showed resistance against CLCuV, indicating that it is possible to transfer resistant genes from the autotetraploid of the diploid donor specie G. arboreum into allotetraploid G. hirsutum through conventional breeding, and durable resistance against CLCuV can then be deployed in the field.

Imaging malignant and apparent malignant transformation of benign gynaecological disease.

Common benign gynaecological diseases, such as leiomyoma, adenomyosis, endometriosis, and mature teratoma, rarely undergo malignant transformation. Benign transformations that may mimic malignancy include benign metastasizing leiomyoma, massive ovarian oedema, decidualization of endometrioma, and rupture of mature teratoma. The aim of this review is to provide a contemporary overview of imaging findings in malignant and apparent malignant transformation of benign gynaecological disease.

Tumor markers: myths and facts unfolded.

OBJECTIVE: The purpose of this article is to review the most commonly used tumor markers in abdominal and pelvic tumors, describe their limitations and explain how to use them in the context of known cancer in order to optimize multidisciplinary care of oncologic patients. CONCLUSION: Tumor markers are important for the diagnosis, staging, monitoring of treatment and detection of recurrence in many cancers. This knowledge is crucial in the daily interpretation of images of oncologic and non-oncologic patients. However, radiologists should also be aware of the limitations of the most commonly used tumor markers and they should not be used solely, but interpreted in conjunction with diagnostic imaging, clinical history and physical examination that will help optimize the multidisciplinary care and management of oncologic patients.

Validation of a new ENT emergencies course for first-on-call doctors.

BACKGROUND: First-on-call ENT cover is often provided by junior doctors with limited ENT experience; yet, they may have to manage life-threatening emergencies. An intensive 1-day simulation course was developed to teach required skills to junior doctors. METHODS: A prospective, single-blinded design was used. Thirty-seven participants rated their confidence before the course, immediately following the course and after a two-month interval. Blinded assessors scored participant performance in two video-recorded simulated scenarios before and after the course. RESULTS: Participant self-rated confidence was increased in the end-of-course survey (score of 27.5 vs 53.0; p < 0.0001), and this was maintained two to four months after the course (score of 50.5; p < 0.0001). Patient assessment and management in video-recorded emergency scenarios was significantly improved following course completion (score of 9.75 vs 18.75; p = 0.0093). CONCLUSION: This course represents an effective method of teaching ENT emergency management to junior doctors. ENT induction programmes benefit from the incorporation of a simulation component.

Lemierre's syndrome: the link between a simple sore throat, sore neck and pleuritic chest pain.

An unusual case of tonsillitis which showed progression to this rare syndrome despite treatment with intravenous antibiotics. Lemierre's syndrome is a rare condition characterised by a triad of: sepsis, thrombophlebitis of the internal jugular vein along with pleuropulmonary and/or distant metastatic abscesses. Diagnosis rests on a high index of suspicion and is confirmed by culture of Fusobacterium spp. from blood or infected sites. Radiological investigations are established aids for confirmation of diagnosis. Treatment is with appropriate antibiotics for at least 6 weeks and surgical drainage of abscesses if required. This case has been presented to highlight the mode of presentation, diagnostic tools employed and the management of the complications that featured in this condition.

Direct phonoplasty under local anaesthetic.

OBJECTIVE: A new technique of direct phonoplasty under local anaesthetic is described. BACKGROUND: Vocal-fold medialization is an accepted method to improve voice in patients with a paralysed vocal fold. Various materials have been used to inject into the paralysed vocal fold, resulting in medialization of the fold and improved phonation. The two established methods are direct injection under general anaesthetic and transcutaneous injection under local anaesthetic; both have advantages and disadvantages. METHOD: A Pentax 80K series flexible endoscope is used to directly inject collagen into the paralysed vocal fold via a reusable 23G endoscopic needle under local anaesthetic. CONCLUSION: New technology and innovation have allowed development of the new technique of direct phonoplasty under local anaesthetic. This combines the advantages of transcutaneous injection under local anaesthetic and direct injection under general anaesthetic, without their disadvantages.

Laser arytenoidectomy for bilateral vocal fold palsy in Parkinson's disease.

We report a case of laser arytenoidectomy for bilateral abductor palsy of the vocal fold in a patient with Parkinson's disease. Parkinson's disease is known to be a rare cause for bilateral vocal fold palsy and this is the second case reported in the English literature. Majority of the reports to date are in the non-English literature. Tracheostomy has been the classic treatment option offered to these patients. To date no report has been found in the literature about a laser arytenoidectomy being performed in a patient suffering from bilateral vocal fold palsy in Parkinson's disease. We have suggested this option as it improves the quality of life of the individual and avoids the difficulty faced by a Parkinson's patient in managing tracheostomy care due to bradykinesia, rigidity and tremor.

Snake bite experience at Pakistan Institute of Medical Sciences.

We reviewed 40 cases of snake bite seen from January, 1996 to December, 1996. Most of the cases survived uneventfully but many developed complications which were either haematologic, (23 patients) or neurological (5 patients). Appropriate treatment was offered in every case. Polyvalent antisnake venom was administered to 30 patients (75%). Premedication used was steroids and antihistamines to prevent anaphylactic reactions. Antifibrinolytic therapy (tranxemic acid) was given to every bleeding patient. The species of offending snake could be recognized in one patient while in all others, it was not possible due to night time incidence and poor description by the patient.

Sero-diagnosis for viral hepatitis in 93 patients admitted with acute hepatitis in three different teaching hospitals in Lahore.

Serodiagnosis was done in 93 patients admitted with acute viral hepatitis (AVH) to three teaching hospitals in Lahore. Five (5.4%) had hepatitis A, 39 (41.9%) hepatitis B (2 of these were anti delta positive) [see erratum notice], 44 (47.3%) probable hepatitis E and 3(3.2%) had HAV/HBV co-infection. Antibody to hepatitis C (anti HCV) was detected in 6 patients (6.4%); 2 with HBV and 4 with probable HEV infection. Excluding 39 patients with hepatitis B and 3 with HBV as part of co-infection, there was evidence of previous HBV infection in 39 out of the remaining 51 patients. In the subset of 6 children, 3 had hepatitis A and 3 hepatitis E. Of these, 5 had evidence of previous exposure to HBV and one was also positive for anti HCV. Our results are suggestive of a strong background of HBV infection raising concern about its chronic sequelae in the community.