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Biomedical subjects

K Moorthy

Publications and source records attributed to K Moorthy.

At least 19 recordsLinked to original sources
PubMed2006

Neuroprotective role of neurokinin B (NKB) on beta-amyloid (25-35) induced toxicity in aging rat brain synaptosomes: involvement in oxidative stress and excitotoxicity.

The brain tissue has a large oxidative capacity, but its ability to combat oxidative stress is limited. In aging brain tissue the oxidative stress increases due to decreased activity of antioxidant enzymes and increased oxidative stress leading to neurodegeneration associated with excitotoxicity. The aim of the present study was to determine the effect of neuropeptides, neurokinin B (NKB) and amyloid beta protein fragment Abeta (25-35) and neurotransmitters N-methyl D-aspartate (NMDA) and Glutamate on rat brain synaptosomes of different age groups. Aging brain functions were assessed by measuring the activities of superoxide dismutase (Mn-SOD) and monoamine oxidase (MAO) and intrasynaptosomal [Ca(2+)](i )levels in presence of neuropeptides and neurotransmitters. Increase in age decreased the SOD and MAO enzyme activities; Abeta (25-35) addition further had damaging/toxic effects on the enzymes, whereas NKB alone and in combination with amyloid lowered the toxic effects caused by Abeta (25-35) addition, which was concentration (peptide) and age dependent. Oxidative stress and excitotoxicity are major consequences associated with the age, [Ca(2+)](i )was increased with the age and the neuropeptides and neurotransmitters elicited significant modulatory effects on it. Our study elucidates an increased activity of SOD, decreased activity of MAO and restoration of [Ca(2+)](i) levels in the presence of NKB and suggests an antioxidant, neuromodulatory and neuroprotective role of tachykinin peptide NKB against the beta amyloid induced toxicity.

Aging↗
PubMed2006

Membrane associated functions of neurokinin B (NKB) on Abeta (25-35) induced toxicity in aging rat brain synaptosomes.

The effect of different concentrations (0.1-5 microM) of neurokinin B (NKB) and Abeta (25-35) on acetylcholine esterase (AChE), Na(+)-K(+) ATPase and membrane fluidity (DPH anisotropy) were investigated in rat brain synaptosomes of 3, 9, 18 and 30 months old. An age dependent decrease was observed for all the three parameters studied. An in vitro incubation of isolated brain synaptosomes with Abeta (25-35) showed toxic effects on all the parameters studied and the peptide had concentration and age dependent effects, while NKB showed stimulating effect on the parameters and the combined NKB+Abeta (25-35) incubations showed a partial reversal effect as compared to the Abeta (25-35) alone. Thus, the results suggest a membrane mediated function for NKB and its role in neuromodulation, neuroprotection and antioxidant property against Abeta (25-35) induced toxicity in aging brain functions.

Acetylcholinesterase↗
PubMed2005

Amelioration of altered antioxidant status and membrane linked functions by vanadium and Trigonella in alloxan diabetic rat brains.

Trigonella foenum graecum seed powder (TSP) and sodium orthovanadate (SOV) have been reported to have antidiabetic effects. However, SOV exerts hypoglycemic effects at relatively high doses with several toxic effects. We used low doses of vanadate in combination with TSP and evaluated their antidiabetic effects on anti-oxidant enzymes and membrane-linked functions in diabetic rat brains. In rats, diabetes was induced by alloxan monohydrate (15 mg/100 g body wt.) and they were treated with 2 IU insulin, 0.6 mg/ml SOV, 5% TSP and a combination of 0.2 mg/ml SOV with 5% TSP for 21 days. Blood glucose levels, activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), Na+/K+ ATPase, membrane lipid peroxidation and fluidity were determined in different fractions of whole brain after 21 days of treatment. Diabetic rats showed high blood glucose (P less than 0.001), decreased activities of SOD, catalase and Na+/K+ ATPase (P less than 0.01, P less than 0.001 and P less than 0.01), increased levels of GPx and MDA (P less than 0.01 and P less than 0.001) and decreased membrane fluidity (P less than 0.01). Treatment with different antidiabetic compounds restored the above-altered parameters. Combined dose of Trigonella and vanadate was found to be the most effective treatment in normalizing these alterations. Lower doses of vanadate could be used in combination with TSP to effectively counter diabetic alterations without any toxic effects.

Animals↗
PubMed2005

Effect of hormone replacement therapy in normalizing age related neuronal markers in different age groups of naturally menopausal rats.

Aging of the normal brain is accompanied by changes in its structure, function, and metabolism. There are significant gender differences in aging brain. Most of these changes increase during menopausal condition in females when the level of estradiol and progesterone are decreased. The objective of this study was to determine the effect of estradiol and progesterone (separate as well as combined) hormones in neuronal tissues from naturally menopausal rats of different age groups. Results show decreased activity of Acetylcholine esterase (AChE) whereas the level of lipid peroxidation increased with age, and after the hormone treatments both AChE activity and level of lipid peroxidation returned to control values. The deposition of lipofuscin, a pigment that accumulated intraneuronally in brain and other tissues and is considered a marker of aging, was increased with aging and the hormone treatment decreased this deposition. The present study clearly shows reduction in risk factors associated with aging in the murine model system by hormone treatments, namely estrogen and progesterone by increasing the activity of acetylcholine esterase and decreasing the levels of lipid peroxidation and lipofuscin deposition in different parts of aging brain. This study suggests that hormone replacement therapy may either reduce or delay the onset of age related diseases like Alzheimer's, Parkinson's and other neurological disorders.

Acetylcholinesterase↗
PubMed2005

Combined treatment of sodium orthovanadate and Momordica charantia fruit extract prevents alterations in lipid profile and lipogenic enzymes in alloxan diabetic rats.

Momordica charantia Linn., commonly called bitter gourd, is a medicinal plant used in the Ayurvedic system of medicine for treating various diseases including diabetes mellitus. Sodium orthovanadate (SOV) is also well-known insulin mimetic and an antidiabetic compound. Our laboratory has been using reduced doses of SOV along with administration of herbal extracts to alloxan diabetic rats and has established this combination as a good antihyperglycemic agent. The present study was undertaken to investigate the effects of treatment of Momordica fruit extract (MFE) and sodium orthovanadate, separately and in combination, on serum and tissue lipid profile and on the activities of lipogenic enzymes in alloxan induced diabetic rats. The results show that there was a significant (p < 0.01) increase in serum total lipids, triglycerides and total cholesterol levels after 21 days of alloxan diabetes. In the liver and kidney of diabetic rats the levels of total lipids and triglycerides also increased significantly (p < 0.01) while levels of total cholesterol decreased significantly (p < 0.01 and p < 0.05, respectively). The lipogenic enzymes showed decreased activity in the diabetic liver, while in kidney they showed an increased activity. When compared with the controls these changes were significant. The treatment of alloxan diabetic rats with MFE and SOV prevented these alterations and maintained all parameters near control values. Most effective prevention was however observed in a combined treatment of Momordica with a reduced dose of SOV (0.2%). The results suggest that Momordica fruit extract and SOV exhibit hypolipidemic as well as hypoglycemic effect in diabetic rats and their effect is pronounced when administered in combination.

Animals↗
PubMed2005

Administration of estradiol and progesterone modulate the activities of antioxidant enzyme and aminotransferases in naturally menopausal rats.

In aging tissues the oxidative stress increases due to decreased activity of antioxidant enzymes and proteolysis increases due to decreased activity of aminotransferases, which can be modified by hormonal replacement therapy (HRT). The aim of the present study was to determine the effect of HRT on the activities of an antioxidant enzyme superoxide dismutase (SOD) and aminotransferases like alanine aminotransferase (Ala-AT) and aspartate aminotransferase in different age groups (12, 18 and 24 months) of naturally menopausal rats. The rats were given the subcutaneous injection of 17beta-estradiol, progesterone and combination of estradiol and progesterone for 1 month. The activity of SOD, Ala-AT and Asp-AT was measured in the brain (cerebral hemisphere, CH), heart, liver, kidney and uterus. The activity of SOD decreased with age in all the tissues taken particularly in liver. After HRT the enzyme activities were increased as compared to age-matched controls in all the tissues of aging rats. The activities of transaminases (Ala-AT and Asp-AT) showed a decrease with age in all the tissues and administration of estradiol and combination of estradiol and progesterone further decreased both the aminotransferases. Our study elucidates that increased activity of SOD contributes in protection of cells from oxygen toxicity by catalyzing the dismutation of free radicals in tissues. Furthermore, the HRT probably decreases gluconeogenesis and proteolysis by decreasing the activities of Ala-AT and Asp-AT in aging rat tissues.

Aging↗
PubMed2004

Robot-assisted laparoscopic Heller cardiomyotomy: preliminary UK results.

BACKGROUND/AIM: Laparoscopic Heller cardiomyotomy is an established modality in the surgical treatment of patients having achalasia cardia. We present our initial experience in robot-assisted laparoscopic Heller cardiomyotomy without addition of an antireflux procedure and discuss the relative merits and disadvantages of the procedure. PATIENTS AND METHODS: Five patients underwent robot-assisted laparoscopic Heller cardiomyotomy between August 2001 and October 2002. The diagnosis had been confirmed by radiology and manometry in all patients prior to surgery. RESULTS: All procedures were completed successfully using the robotic system, without conversion to open procedure. Mucosal perforation occurred in 1 patient and was sutured robotically. The average operative time was 114.8 (range 65-160) min which is comparable to laparoscopic procedures. After a mean follow-up period of 9.4 (range 3-17) months, 4 patients remained completely asymptomatic, and 1 patient has benefited from symptomatic improvement. CONCLUSIONS: The enhanced dexterity and the high-quality three-dimensional vision available with robot-assisted surgery make the application of this technology highly suitable for Heller cardiomyotomy. The minimal lateral and posterior dissection due to the wristed instruments avoids the need for an antireflux procedure.

Adult↗
PubMed2004

Bimodal assessment of laparoscopic suturing skills: construct and concurrent validity.

BACKGROUND: The assessment of technical skills should provide objective feedback and judge suitability of progress during training. The aim of this study was to validate two objective assessment techniques for laparoscopic suturing and demonstrate a correlation between them. METHODS: Six experts, seven surgeons skilled in laparoscopic suturing, and 13 with no laparoscopic suturing skills were asked to place two or three intracorporeal sutures on a synthetic suture pad. The latter group was given video-based instructions prior to the execution of the sutures. Ergonomic conditions were standardized for all subjects. The procedures were recorded on videotape and two blinded observers rated the first suture of each subject on a 29-point checklist. A motion analysis system, Imperial College Surgical Assessment Device, was used to assess psychomotor skills. RESULTS: There was a significant difference in the time taken (p = 0.000) and total path length (p = 0.000) per suture across the groups. There were also a significant difference in the total checklist score (p = 0.000) and its individual categories. The was a strong correlation between the total path length and the total checklist score (coefficient, 0.78; p < 0.001). CONCLUSIONS: A combination of the motion analysis system and the checklist would make the process of formative feedback during the learning of intracorporeal suturing objective and comprehensive.

Clinical Competence↗
PubMed2004

An innovative method for the assessment of skills in lower gastrointestinal endoscopy.

BACKGROUND: Although virtual reality (VR) simulators can be used ability to objectively assess skills in endoscopy, the evaluation is solely quantitative. We have developed a novel method for the objective assessment of technical skills in lower gastrointestinal (GI) endoscopy that incorporates qualitative as well as quantitative measures. METHODS: We developed a virtual endoscopy suite by deconstructing the VR simulator to enable a more realistic and ergonomic placement of the monitor. Trainee endoscopists with varying levels of experience performed the case 4 task of the simulator. Ten essential components of endoscopic performance were rated on a five-point Likert scale (global score) by three independent observers. These observers viewed two videos (one showing scope handling and the other showing the monitor image), which were synchronized and played simultaneously. RESULTS: The study population comprised six experts (group 1, > 200 procedures), seven subjects with intermediate experience (group 2, 20-80 procedures), and seven novices (group 3, 1-10 procedures). The global score was found to discriminate the level of skills across all three groups (p < 0.001). There were significant differences between groups 1 and 2 (p = 0.003) and groups 2 and 3 (p = 0.004). There was a significant correlation between the global score and the percentage of red-out (without vision) as recorded by the simulator (correlation coefficients = -0.61, p = 0.004). CONCLUSION: This novel method for the assessment of technical skills in lower GI endoscopy has construct validity and high interrater reliability.

Clinical Competence↗
PubMed2004

Dexterity enhancement with robotic surgery.

BACKGROUND: The aim of this study was to quantify the extent of dexterity enhancement in robotic surgery as compared to laparoscopic surgery. METHODS: Ten surgeons with varying laparoscopic suturing experience were asked to place three sutures on a suture pad. The sutures were placed laparoscopically, robotically with 2-D vision and robotically with 3-D vision. The da Vinci systems Application Programming Interface (API) was used for positional data. A validated motion analysis system was used for data retrieval for the laparoscopic task. Custom software was developed for data analysis. RESULTS: Compared to laparoscopic suturing, when the task was undertaken robotically with 2-D vision there was a 20% reduction in the time taken but this was not significant (p = 0.07). There was a 55% reduction in the path traveled by the right hand (p = 0.01) and a 45% reduction in the path traveled by the left hand (p = 0.008). When the task was undertaken robotically with 3-D vision, there was a 40% reduction in the time taken (p = 0.01). There was a 70% reduction in the path traveled by right hand (p = 0.008) and a 55% reduction by the left hand (p = 0.08). CONCLUSIONS: The presence of wristed instrumentation, tremor abolition, and motion scaling enhance dexterity by nearly 50% as compared to laparoscopic surgery. 3-D vision enhances dexterity by a further 10-15%. In addition, the presence of 3-D vision results in a 93% reduction in skills-based errors.

Clinical Competence↗
PubMed2004

The benefits of stereoscopic vision in robotic-assisted performance on bench models.

BACKGROUND: Previous studies have failed to establish clear advantages for the use of stereoscopic visualization systems in minimal-access surgery. The aim of this study was to objectively assess whether stereoscopic visualization improves performance on bench models using the da Vinci robotic system. METHODS: Eleven surgeons carried out a series of four tasks. Positional data streamed from the da Vinci system was analyzed by means of a previously validated custom-designed software-package. An independent blinded observer scored errors. Statistical analysis included the Wilcoxon signed rank test. A p < 0.05 was deemed significant. RESULTS: We found significant improvements in all tasks and for all parameters (p < 0.05). In addition, a significantly lower number of errors was scored using the stereoscopic mode as compared to the standard two-dimensional image (p < 0.001). CONCLUSION: Robotic-assisted performance on bench models is more efficient and accurate using stereoscopic visualization.

Data Display↗
PubMed2004

Laparoscopic virtual reality and box trainers: is one superior to the other?

BACKGROUND: Virtual reality (VR) simulators now have the potential to replace traditional methods of laparoscopic training. The aim of this study was to compare the VR simulator with the classical box trainer and determine whether one has advantages over the other. METHODS: Twenty four novices were tested to determine their baseline laparoscopic skills and then randomized into the following three group: LapSim, box trainer, and no training (control). After 3 weekly training sessions lasting 30-min each, all subjects were reassessed. Assessment included motion analysis and error scores. Nonparametric tests were applied, and p < 0.05 was deemed significant. RESULTS: Both trained groups made significant improvements in all parameters measured ( p < 0.05). Compared to the controls, the box trainer group performed significantly better on most of the parameters, whereas the LapSim group performed significantly better on some parameters. There were no significant differences between the LapSim and box trainer groups. CONCLUSIONS: LapSim is effective in teaching skills that are transferable to a real laparoscopic task. However, there appear to be no substantial advantages of one system over the other.

Adult↗
PubMed2004

Qualitative and quantitative analysis of the learning curve of a simulated surgical task on the da Vinci system.

BACKGROUND: Robotic telemanipulation systems provide solutions to the problems of less dexterity and visual constraints of minimally invasive surgery (MIS). However, their influence over surgeons' dexterity and learning curve needs to be assessed. We present motion analysis as an objective method to measure performance and learning progress.METHODS. Thirteen surgeons completed five synthetic small bowel anastomoses using the da Vinci system. Objective Structured Assessment of Technical Skills (OSATS) allowed qualitative analysis. Quantitative analysis used API software of the system to retrieve real-time robotic signal data of time, path length, and number of movements. Wilcoxon signed ranks test was used for statistical analysis. A p value <0.05 was considered significant.RESULTS. OSATS global scores were 18.6 points for the first attempt and 26 for the fifth attempt ( p < 0.02, Cronbach's alpha = 0.894). Paired data of motion analysis for attempts 1 vs 5 showed significant change: time taken 3507 sec and 2287 sec ( p < 0.008), total number of movements 2411 and 1387 ( p = 0.01), total path length 21,630 cm and 13,941 cm ( p = 0.01).CONCLUSIONS. A rapid learning curve to a competent level using the da Vinci system is possible aided by the system's intuitive motion. Motion analysis is a useful tool to measure performance in the da Vinci system compared to OSATS and time alone.

Anastomosis, Surgical↗
PubMed2004

Laparoscopic skills training and assessment.

BACKGROUND: The introduction of laparoscopic techniques to general surgery was associated with many unnecessary complications, which led to the development of skills laboratories to train novice laparoscopic surgeons. This article reviews the tools currently available for training and assessment in laparoscopic surgery. METHODS: Medline searches were performed to identify articles with combinations of the following key words: laparoscopy, training, curriculum, virtual reality and assessment. Further articles were obtained by manually searching the reference lists of identified papers. RESULTS: Current training involves the use of box trainers with either innate models or animal tissues; it lacks objective assessment of skill acquisition. Virtual reality simulators have the ability to teach laparoscopic psychomotor skills, and objective assessment is now possible using dexterity-based and video analysis systems. CONCLUSION: The tools are now available for the development of a structured, competency-based, laparoscopic surgical training programme.

Clinical Competence↗
PubMed2004

Effects of sodium-orthovanadate and Trigonella foenum-graecum seeds on hepatic and renal lipogenic enzymes and lipid profile during alloxan diabetes.

Sodium-orthovanadate (SOV) and seed powder of Trigonella foenum graecum Linn. (common name: fenugreek, family: Fabaceae) (TSP) besides being potential hypoglycemic agents have also been shown to ameliorate altered lipid metabolism during diabetes. This study evaluates the short-term effect of oral administration of SOV and TSP separately and in concert (for 21 days) on total lipid profile and lipogenic enzymes in tissues of alloxan diabetic rats. Diabetic rats showed 4-fold increase in blood glucose. The level of total lipids, triglycerides and total cholesterol in blood serum increased significantly during diabetes. During diabetes the level of total lipids increased significantly (P < 0.001) in liver and in kidney by 48% and 55%, respectively, compared to control. Triglycerides level increased by 32% (P < 0.01) in liver and by 51% (P < 0.005) in kidney, respectively, compared to control. Total cholesterol level also increased significantly in both liver and kidney (P < 0.01 and P < 0.001, respectively). The activities of NADP-linked enzymes; namely glucose-6-phosphate dehydrogenase (G6PDH), malic enzyme (ME), isocitrate dehydrogenase (ICDH), and the activities of lipogenic enzymes namely ATP-citrate lyase (ATP-CL) and fatty acid synthase (FAS) were decreased significantly in liver and increased in kidney during diabetes as compared to control. SOV and TSP administration to diabetic animals prevented the development of hyperglycemia and alteration in lipid profile in plasma and tissues and maintained it near normal. Maximum prevention was observed in the combined treatment with lower dose of SOV (0.2%) after 21 days. We are presenting for the first time effectiveness of combined treatment of SOV and TSP in amelioration of altered lipid metabolism during experimental type-I diabetes.

Alloxan↗
PubMed2004

Estradiol and progesterone treatments change the lipid profile in naturally menopausal rats from different age groups.

The effect of estradiol and progesterone therapy in serum and liver on the lipid profile of naturally menopausal albino rats of the Wistar strain of different age groups (12,18 and 24 months) have been measured and compared with the age matched groups. Three months old rats were used as young controls. The aged rats were administered subcutaneous injection of 17-beta-estradiol (0.1 microg/g body weight), progesterone (2.5 microg/g body weight) and similar concentrations of both in combined treatment for 1 month and the level of triglycerides (TG), total lipids (TL), total cholesterol (TC), high density lipoprotein (HDL), low density lipoprotein (LDL) and very low density lipoprotein (VLDL) were measured in serum and liver of 3, 12, 18 and 24 months old control as well as treated groups. The results show that TG, HDL, VLDL levels were increased significantly by 71%, 155%, 54%, respectively in liver of 24 months old rats by combination treatment when compared with age matched control animals. The levels of TL, TC and LDL were decreased by 20%, 31%, and 30%, respectively in serum of 12 months old rats in combination treatment group. The effect was more significant in 12 and 24 months old female rats with administration of estrogen and combined (EP) treatments. The results indirectly suggest that hormone replacement therapy (HRT) can reduce the risk of cardiovascular disease (CVD) thereby playing a cardio-protective role by restoring lipid and hormone levels to the similar levels as found in young female animals.

Aging↗
PubMed2004

Objective evaluation of the effect of noise on the performance of a complex laparoscopic task.

BACKGROUND: Noise in operating rooms has been found to be much higher than the recommended level of 45 dB. The aim of this study was to objectively evaluate the effect of noise and music on the performance of a complex surgical task. METHODS: Twelve surgeons with varying experience in laparoscopic suturing undertook 3 sutures in a laparoscopic trainer under 3 conditions: quiet, noise at 80 to 85 dB, and music. Other than the test conditions, all other conditions were standardized. A validated motion analysis system was used to assess performance. The tasks were recorded by video and played back to 2 blinded observers who rated the surgeons' performance on a global rating scale by observing the tasks for accuracy, knot quality, and number of nonpurposeful movements. RESULTS: Time taken for the tasks (P=.78), total number of movements (P=.78), total path length (P=.47), global score (P=.54), accuracy, and knot quality remained unchanged across the 3 conditions. The main study measures had a high test-retest reliability and internal consistency. No learning effect was seen across the 3 conditions. CONCLUSIONS: Surgeons can effectively "block out" noise and music. This is probably due to the high levels of concentration required for the performance of a complex surgical task. Future research should focus on the effect of these conditions on communication in the operating room.

Adult↗