Sacral nerve stimulation can be an effective treatment for low anterior resection syndrome

AIM

Sacral nerve stimulation has become a preferred method for the treatment of faecal incontinence in patients who fail conservative (non-operative) therapy. In previous small studies, sacral nerve stimulation has demonstrated improvement of faecal incontinence and quality of life in a majority of patients with low anterior resection syndrome. We evaluated the efficacy of sacral nerve stimulation in the treatment of low anterior resection syndrome using a recently developed and validated low anterior resection syndrome instrument to quantify symptoms.

METHOD

A retrospective review of consecutive patients undergoing sacral nerve stimulation for the treatment of low anterior resection syndrome was performed. Procedures took place in the Division of Colon and Rectal Surgery at two academic tertiary medical centres. Pre- and post-treatment Cleveland Clinic Incontinence Scores and Low Anterior Resection Syndrome scores were assessed.

RESULTS

Twelve patients (50% men) suffering from low anterior resection syndrome with a mean age of 67.8 (±10.8) years underwent sacral nerve test stimulation. Ten patients (83%) proceeded to permanent implantation. Median time from anterior resection to stimulator implant was 16 (range 5-108) months. At a median follow-up of 19.5 (range 4-42) months, there were significant improvements in Cleveland Clinic Incontinence Scores and Low Anterior Resection Syndrome scores (P < 0.001).

CONCLUSION

Sacral nerve stimulation improved symptoms in patients suffering from low anterior resection syndrome and may therefore be a viable treatment option.

Resonant silicon nanoparticles for enhancement of light absorption and photoluminescence from hybrid perovskite films and metasurfaces

Recently, hybrid halide perovskites have emerged as one of the most promising types of materials for thin-film photovoltaic and light-emitting devices because of their low-cost and potential for high efficiency. Further boosting their performance without detrimentally increasing the complexity of the architecture is critically important for commercialization. Despite a number of plasmonic nanoparticle based designs having been proposed for solar cell improvement, inherent optical losses of the nanoparticles reduce photoluminescence from perovskites. Here we use low-loss high-refractive-index dielectric (silicon) nanoparticles for improving the optical properties of organo-metallic perovskite (MAPbI₃) films and metasurfaces to achieve strong enhancement of photoluminescence as well as useful light absorption. As a result, we observed experimentally a 50% enhancement of photoluminescence intensity from a perovskite layer with silicon nanoparticles and 200% enhancement for a nanoimprinted metasurface with silicon nanoparticles on top. Strong increase in light absorption is also demonstrated and described by theoretical calculations. Since both silicon nanoparticle fabrication/deposition and metasurface nanoimprinting techniques are low-cost, we believe that the developed all-dielectric approach paves the way to novel scalable and highly effective designs of perovskite based metadevices.

Prospective analysis of the sealing ability of the ENSEAL® G2 Articulating Tissue Sealer and transector on human mesenteric vessels in colorectal surgery

BACKGROUND

The sealing and transection of mesenteric vessels is a crucial step in minimally invasive colorectal surgery. We examined the sealing quality of the ENSEAL^® G2 Articulating Tissue Sealer in three different articulations in mesenteric vessels.

METHODS

This was a prospective experimental study within a tertiary healthcare center, and 30 patients were recruited. Burst pressures for each specimen were measured as the primary outcome. Ten specimens at each of the three articulations were also histologically assessed for the quality of seal.

RESULTS

We evaluated 54 sets of specimens from 30 patients for bursting pressure, all of which were harvested and sealed in the operating room. No statistical difference was seen in burst pressures from seals recorded at no angulation, half-maximal angulation, or maximal angulation (1604, 1507, 1478 mmHg; p = 0.07). Histological analysis showed no statistical differences in the average vessel diameter (p = 0.57), lateral extent of thermal injury (p = 0.48), degree of vascular sclerosis, or the integrity of seal at the three articulations. No cases of intraoperative or postoperative bleeding were observed in any of the patients. Five (16.7%) of the ENSEAL^® devices developed breaks in the black, heat-shrink, polyethylene covering as a result of repeated articulation and disarticulation. Electrical arcing did not appear to have occurred as a result of the break, although this was not formally examined.

CONCLUSIONS

The maximum sustainable pressure in mesenteric vessels sealed with a bipolar electrothermal device is supraphysiological, and consequently, the device can be safely used at various articulations to seal vessels during colorectal surgery.

Role of oxidative stress and antioxidants in neurodegenerative diseases

Neurodegenerative diseases (NDD) are a group of illness with diverse clinical importance and etiologies. NDD include motor neuron disease such as amyotrophic lateral sclerosis (ALS), cerebellar disorders, Parkinson's disease (PD), Huntington's disease (HD), cortical destructive Alzheimer's disease (AD) and Schizophrenia. Numerous epidemiological and experimental studies provide many risk factors such as advanced age, genetic defects, abnormalities of antioxidant enzymes, excitotoxicity, cytoskeletal abnormalities, autoimmunity, mineral deficiencies, oxidative stress, metabolic toxicity, hypertension and other vascular disorders. Growing body of evidence implicates free radical toxicity, radical induced mutations and oxidative enzyme impairment and mitochondrial dysfunction due to congenital genetic defects in clinical manifestations of NDD. Accumulation of oxidative damage in neurons either primarily or secondarily may account for the increased incidence of NDD such as AD, ALS and stroke in aged populations. The molecular mechanisms of neuronal degeneration remain largely unknown and effective therapies are not currently available. Recent interest has focused on antioxidants such as carotenoids and in particular lycopene, a potent antioxidant in tomatoes and tomato products, flavonoids and vitamins as potentially useful agents in the management of human NDD. The pathobiology of neurodegenerative disorders with emphasis on genetic origin and its correlation with oxidative stress of neurodegenerative disorders will be reviewed and the reasons as to why brain constitutes a vulnerable site of oxidative damage will be discussed. The article will also discuss the potential free radical scavenger, mechanism of antioxidant action of lycopene and the need for the use of antioxidants in the prevention of NDD.

Induction of tumours by Indian dietary constituents

Fishes and vegetables are preserved by salting and sundrying; and later fried in oil and consumed. Such preparations have been found to contain polycyclic aromatic hydrocarbons, and are genotoxic and mutagenic. The potential carcinogenic effects of these and other dietary items have been studied by oral feeding to swiss mice at 100 mg/animal/day for 12 months; and observing upto two years. When so prepared and tested, chillies (Capsicum annum L.) produce adenocarcinomas in the abdomen in 35% of animals; Sundakkai (Solanum torvum), hepatic heamangiomas in 30%; Ribbon fish (Trichurus lepturus), squamous gastric carcinoma in 20%; cluster beans (Cyomopsis tetragonoloba), fat deposition throughout the abdomen. While whitebait fish (Stolephorus bataviensis) and seer fish (Scomberomorus commersonnii) have no effect. Fried mustard (Brassica juncea) causes severe necrosis of the liver (25%), but no tumours. Consumption of oil fried foods in high doses can lead to variety of deleterious biological effects. Raw cinnamon (Cinnamon zelanicum) is tumourigenic, inducing squamous pappillomas in some and poorly differentiated carcinomas in others.

Genotoxic effects of some foods & food components in Swiss mice

A number of commonly consumed foods and food components in south India were screened for their genotoxic effects on Swiss mice. Salted, sundried and oil fried vegetables and fishes induced chromosomal aberrations, sperm head abnormalities and micronuclei production, which were comparable to the effect of the positive control viz., 20-methylcholanthrene. Spices like Cissus quadrangularis (an indigenous herb used in certain south Indian dishes) and pyrolysed cumin and aniseeds showed moderate effects. Calamus oil, widely used in pharmaceuticals was highly effective. All the three parameters of genotoxicity gave similar results.

Mutagenic activity of south Indian food items

Dietary components and food dishes commonly consumed in South India were screened for their mutagenic activity. Kesari powder, calamus oil, palm drink, toddy and Kewra essence were found to be strongly mutagenic; garlic, palm oil, arrack, onion and pyrolysed portions of bread toast, chicory powder were weakly mutagenic, while tamarind and turmeric were not. Certain salted, sundried and oil fried food items were also mutagenic. Cissus quadrangularis was mutagenic, while 'decoctions' of cumin seeds, aniseeds and ginger were not. Several perfumes, essential oils and colouring agents, which are commonly used were also screened and many of them exhibited their mutagenic potential by inducing the 'reverse mutation' in Salmonella typhimurium tester strains.

Mutagenicity of nitrosated food items

Several food items, commonly consumed in South India, after nitrite treatment under simulated gastric conditions were found to be mutagenic in Salmonella typhimurium tester strain TA 100. Dichloromethane extracts containing the volatile nitroso compounds and ethyl-acetate extracts with the non-volatile nitroso compounds of some of the food items exhibited mutagenicity.

Presence of polycyclic aromatic hydrocarbons in some South Indian food components

South Indian food dishes, comprising several deep fried items have been proved to be mutagenic. Polycyclic aromatic hydrocarbons (PAHs) such as, benzo(a)pyrene, chrysene and dibenzanthracene, which are potent and proven carcinogens have been identified and quantified in several of the commonly consumed South Indian food dishes and food components. Most of the pyrolysed items contained PAHs in appreciable quantities. PAHs were detected in significant levels in salted, sundried and oil fried vegetables and fishes. Some of the raw and uncooked food components also revealed the presence of PAHs.