Optimal structure for automatic processing of DNA sequences.

The faithful recovery of the base sequence in automatic DeoxyriboNucleic Acid (DNA) sequencing fundamentally depends on the underlying statistics of the DNA electrophoresis time series. Current DNA sequencing algorithms are heuristic in nature and modest in their use of statistical information. In this paper, a formal statistical model of the DNA time series is presented and then used to construct the optimal maximum-likelihood (ML) processor. The DNA-ML algorithm that is derived in this paper features Kalman prediction of peak locations, peak parameter estimation, whitened waveform comparison and multiple hypothesis processing using the M-algorithm. Properties of the algorithm are examined using both simulated and real data. Model parameters of critical importance and their impact on different types of error mechanisms, such as insertions and deletions, are pointed out. The statistical model of the DNA time-series and the structure of the DNA-ML algorithm provides a basis for future investigation and refinement of DNA sequencing techniques.

Acute embolic occlusion of the superior mesenteric artery: a case report and discussion of management.

INTRODUCTION: We present a case of acute embolus to the superior mesenteric artery (SMA). CLINICAL PICTURE: A 70-year-old gentleman with atrial fibrillation complained of colicky abdominal pain with clinical signs of tenderness and mild guarding. TREATMENT AND OUTCOME: Laparotomy revealed extensive bowel ischaemia but no overt infarction. The SMA was occluded by an embolus at the root of the mesentery and balloon catheter embolectomy was carried out at once. Bowel resection was deferred in order to allow clear demarcation of gangrene to avoid sacrificing unnecessary length. At second look laparotomy, 1.2 m of bowel from mid-jejunum to mid-ileum was resected, salvaging about 1 m of previously dusky small and large bowel. CONCLUSION: This case illustrates the importance of accurate history taking, the role of early intervention and the usefulness of a second look laparotomy in cases of mesenteric ischaemia to minimise the extent of bowel resection.

Predictive head movement tracking using a Kalman filter.

The use of head movements in control applications leaves the hands free for other tasks and utilizes the mobility of the head to acquire and track targets over a wide field of view. We present the results of applying a Kalman filter to generate prediction estimates for tracking head positions. A simple kinematics approach based on the assumption of a piecewise constant acceleration process is suggested and is shown to track head positions with an rms error under 2 degrees for head movements with accelerations smaller than 3000 degrees /s. To account for the wide range of head dynamic characteristics, an adaptive approach with input estimation is developed. The performance of the Kalman filter is compared to that based on a simple polynomial predictor.

Endovascular exclusion of aberrant splenic artery aneurysm with covered stent.

The splenic artery arising from the superior mesenteric artery is an uncommon anatomical variant. This aberrant origin may rarely be associated with an aneurysm. Previous cases have been managed with surgery and combined surgical/endovascular or endovascular techniques, with the latter involving occlusion of the aneurysm with coils. We report a case of aberrant splenic artery aneurysm that was excluded with a balloon-mounted covered stent, and discuss the technical issues encountered in using this approach. A follow-up computed tomography performed six months after the covered stent placement showed persistent exclusion with marked shrinkage of the aneurysm sac.

Laparoscopic sleeve gastrectomy: a novel procedure for weight loss.

INTRODUCTION: Morbid obesity is associated with increased morbidity and mortality. Bariatric surgery offers morbidly obese individuals substantial and sustainable weight loss and reduction in obesity-related comorbidities. Laparoscopic sleeve gastrectomy (LSG) is a new restrictive procedure in bariatric surgery. We aimed to evaluate our experience with LSG with regard to its safety and feasibility and early weight loss. METHODS: The surgical outcome, complications and early clinical results of all patients who underwent LSG at Singapore General Hospital were studied. RESULTS: 30 patients underwent LSG between December 2008 and October 2010. The mean preoperative weight of the patients was 113.4 (range 91.0-170.0) kg, while the mean body mass index (BMI) was 42.6 (range 33.0-60.0) kg/m². Diabetes mellitus was present in 39 percent of the patients, hypertension in 43 percent, hyperlipidaemia in 35 percent, obstructive sleep apnoea in 30 percent and osteoarthritis in 22 percent. The majority of patients had two or more obesity-related comorbidities (52 percent). Mean operative time was 142 (range 80-220) minutes and median duration of postoperative stay was three days. At two weeks, one, three and six months post operation, the mean BMI was 38.6 kg/m², 37.8 kg/m², 34.5 kg/m² and 30.8 kg/m², the mean percentage of excess weight loss was 17.7 percent, 23.3 percent, 40.9 percent and 56.7 percent, and absolute weight loss was 8.00 kg, 11.52 kg, 18.77 kg and 26.85 kg, respectively. CONCLUSION: LSG is a promising procedure for surgical treatment of obesity, with good early weight loss and low morbidity.

Is there a place for N.O.T.E.S. in the diagnosis and treatment of neoplastic lesions of the pancreas?

Natural orifice transluminal endoscopic surgery (NOTES) is the latest minimally invasive technique in the surgical armamentarium. Indeed it is stoking controversy already among both practitioners and patients, challenging established surgical, ethical and even moral principles. One organ which has been at the forefront of minimally invasive intervention is the pancreas. This review looks at the basis for evolving NOTES capabilities in the diagnosis and treatment of pancreatic diseases, with particular reference to neoplastic lesions and their complications. A summary of recent advancements in gastro-intestinal endoscopy and laparoscopic surgery as applied to the pancreas is presented. The possible role and feasibility of NOTES are outlined against this background.

Self-expanding nitinol stents in recanalisation of long-length superficial femoral artery occlusions in patients with critical limb ischaemia.

INTRODUCTION: This study aims to evaluate our experience with self-expanding nitinol stent- enabled recanalisation of long-length occlusions (30 cm or more) of the superficial femoral artery (SFA). METHODS: 573 patients underwent 842 lower limb interventions from August 2006 to December 2008. A retrospective review of patients undergoing recanalisation of long-length SFA occlusions with self-expanding nitinol stents and an evaluation of their patency and impact on limb salvage, were done. RESULTS: 22 patients (mean age 62.5 years, male: female ratio 11:11) underwent 22 long-length SFA stenting procedures. The spectrum of critical limb ischaemia included rest pain (five), ulcer (six) and gangrene (11). Length of occlusions varied from 30 cm to 45 cm (average length 36.4 cm). Five patients had stents placed through the ipsilateral popliteal artery approach, and the rest had stents placed through the femoral artery approach. All patients were followed up over an average duration of 12 months. One patient died due to associated medical conditions during this period. Six out of 21 (28.6 percent) of the stents thrombosed completely on one year follow-up. Of these, two patients underwent amputation, one patient had a bypass, and the stent in two patients were recanalised with balloon angioplasty. All remaining patent stents showed varying degrees of stenoses at one year. The overall limb salvage rate at one year following stent placement was 81 percent. CONCLUSION: Our experience showed the beneficial result of long-length SFA stent placement with good limb salvage outcome. Repeat interventions may be required to maintain the patency of stents in these patients.

Ischaemic preconditioning protects against ischaemia/reperfusion injury: emerging concepts.

INTRODUCTION: Ischaemic preconditioning (IP) has emerged as a powerful method of ameliorating ischaemia/reperfusion (I/R) injury to the myocardium. This review investigates whether this phenomenon is universally applicable in modulating I/R injury to other tissues. METHODS: A Medline search was conducted to identify both animal and human studies that described IP-induced protection from I/R injury in a variety of non-cardiac organ systems. Particular emphasis was placed on elucidation of underlying physiological concepts. RESULTS AND CONCLUSIONS: IP utilises endogenous mechanisms in skeletal muscle, liver, lung, kidney, intestine and brain in animal models to convey varying degrees of protection from I/R injury. To date there are few human studies, but recent reports suggest that human liver, lung and skeletal muscle acquire similar protection after IP. Specifically, preconditioned tissues exhibit reduced energy requirements, altered energy metabolism, better electrolyte homeostasis and genetic re-organisation, giving rise to the concept of 'ischaemia tolerance'. IP also induces 'reperfusion tolerance' with less reactive oxygen species and activated neutrophils released, reduced apoptosis and better microcirculatory perfusion compared to non-preconditioned tissue. Systemic I/R injury is also diminished by preconditioning. IP is ubiquitous but more research is required to fully translate these findings to the clinical arena.

Effects of warm-up on exercise capacity, platelet activation and platelet-leucocyte aggregation in patients with claudication.

BACKGROUND: The effects of exercise and warm-up were investigated in patients with claudication. METHODS: This case-control crossover study involved two treadmill exercise tests, one preceded by a warm-up. Exercise continued until maximal leg pain (patients with claudication) or exhaustion (controls). Blood was taken before, and 5 and 60 min after exercise for flow cytometric analysis of platelet activation and platelet-leucocyte aggregation. RESULTS: Both cohorts (eight patients with claudication of median age 63 years and eight healthy controls of median age 63.5 years) demonstrated improvement in exercise capacity after warm-up (13.1 per cent, P = 0.012 and 15.6 per cent, P = 0.008 respectively). Platelet activation increased after exercise in patients with claudication (fibrinogen binding: 1.11 per cent before exercise versus 2.63 per cent after exercise, P = 0.008; P-selectin: 0.68 versus 1.11 per cent, P = 0.028). Neither agonist stimulation nor warm-up altered this trend. Platelet-leucocyte (PLA) and platelet-neutrophil (PNA) aggregation were similarly increased immediately after exercise in patients with claudication (PLA: 7.6 versus 13.0 per cent, P = 0.004; PNA: 6.8 versus 10.2 per cent, P = 0.012). These remained high 60 min after exercise only in patients with claudication, but recovered to baseline levels when preceded by warm-up. Warm-up significantly desensitized PNA after stimulation with 10 micromol/l adenosine 5'-diphosphate at all time points. CONCLUSION: Warm-up increased the exercise capacity of patients with claudication. Exercise induced a thromboinflammatory response, with PLA and PNA persistently increased after 60 min in patients with claudication, an effect diminished after warm-up.

Systemic administration of naked DNA with targeting specificity to mammalian kidneys.

A major challenge for gene therapy is to be able to deliver efficiently the gene of interest to specific cell types. Here we describe a safe and simple effective naked DNA gene delivery method, via inferior vena cava (IVC) injection, to the recipient's kidneys. It was further demonstrated that gene expression was concentrated in the proximal tubular epithelial cells of the cortico-medullary region of the kidney. Confocal microscopy analyses demonstrated the presence of the exogenous DNA in the renal cell membrane 10 min postgene delivery. However, it was only by 30 min that the presence of the exogenous DNA could be detected in the cell cytoplasm and in the nuclei of the renal cells. Stable expression of the beta-galactosidase gene could be detected for up to 35 days and no toxicity or any adverse pathological effect associated with the delivery method could be observed. Importantly, this IVC gene delivery method could promote the targeting of genes to carcinoma established in the kidney of SCID mice. These results provide the first evidence to support that stable gene expression could be achieved in the renal cells of kidney and the established carcinoma in the kidneys following in vivo gene delivery with naked DNA and could therefore provide the potential to design protocols for the gene therapy of the kidney diseases.

Pharmacognostical studies on changeri oxalis corniculata linn. (Oxalidaceae):.

Pharmacognostical studies on Oxalis corniculate (Changeri) stem and leaves along with pre-liminary phytochemical studies are presented in this paper.

Models of local behavior of DNA electrophoresis peak parameters.

Many base calling algorithms implicitly or explicitly rely on predictions of local sequence parameters such as amplitude, peak time and peak width. For example, an algorithm may search for the next peak about a predicted peak time formed by adding the mean peak separation to the last position measurement. In this paper, covariance models are presented which characterize the dependence of peak parameters on those of other peaks. Based on experimental measurements, the model features an exponential decay in peak time jitter covariance with respect to base separation. Both peak amplitude and peak width are modelled as being uncorrelated with those of adjacent bases. In the model, linear expressions are given to describe the growth in peak time jitter and peak width as a function of base position while other parameters, such as amplitude variance, are modeled by constants. Together, these results form a simple model which may be used in the derivation of new sequencing algorithms or in simulations for the testing of such algorithms. We suggest that the correlation of the peak times is related to the Kuhn length of the single-stranded DNA fragments.

A comparison between open versus laparoscopic assisted colonic pouches for rectal cancer.

The aim of this prospective study was to compare the surgical outcomes in patients undergoing laparoscopic assisted vs. open ultralow anterior resection (ULAR) with the creation of a colonic pouch-anal anastomosis. Patients undergoing ULAR with creation of a colonic pouch and who either had conventional open (CO) or laparoscopic assisted (LA) surgery in colorectal cancer were studied and compared. There were 33 patients, 22 in CO group and 11 in LA group. The groups were comparable for age, sex, tumour and anastomotic heights from anal verge, stage of disease, length of specimen removed and duration of surgery. Incisions were significantly shorter in the LA group (median, 9 cm vs. 16 cm, p = 0.01). Less parenteral analgesia was required in the LA group (2 days vs. 3 days, p = 0.05), but there were no significant differences in the time to passage of flatus, commencement of oral fluids or solid foods and length of hospital stay. There was no difference in morbidity or mortality. With regards to patients with Dukes A to C disease only, at a median of 12 months of follow-up, there was no patient with local or port site recurrence in the LA group. In the CO group, there was one local recurrence and two with distal metastases. In conclusion, laparoscopic assisted ULAR with colonic J pouch anal anastomosis is feasible, easy to perform and safe. It s advantages include significantly shorter incision and lower analgesic requirements postoperatively. Return of bowel function and length of hospital stay, however, are comparable to those of conventional open surgery.

Pharmacognostical stucies on the seeds of mulam citrullus lanatus (thunb.) mats & nakai (cucurbitacae).

In the Siddha system of Medicine cotyledons of the seeds of C. Lanatus are known as Mulam/Pullum/Pitcha (Tamil) and used as Pulukolli (Vermifuge), Karpa moolikai (General tonic) and as Aanmeiperukki (Aphrodisiac). In the Ayurvedic system of Medicine seeds are said to have properties like Sheeta (cooling), Mootrala (Diuretic) and Vrshya (Aphrodisiac). The present paper deals with macro and microscopical studies, maceration, histochemical tests, solubility, physical contents, extractive values, tests for inorganic and organic constituents, U.V. and thin layer chromatographic studies.