Ergonomic evaluation and performance of a new handle for laparoscopic tools in surgery.

This paper presents a new handle for instruments used in laparoscopic surgery. This new handle has been designed to provide the best ergonomic and usability features required in this kind of surgical interventions. The main novelty of this handle is that the opening and closing motion of the end-effector is operated with the thumb using a lever located on the top of the handle. This enables the surgeon to reach the patient's organs without adopting extremely awkward postures. In order to demonstrate its advantages, the handle has been tested and compared with another commercial handle in terms of efficiency, effectiveness, and satisfaction. To this end, volunteers have been selected for participation in the experimental evaluation, which comprised two types of surveys: objective and subjective. Electromyography and goniometric studies provide objective parameters for evaluation. Questionnaires are used for the subjective assessment. Outstanding results include the lower level of pain reported by the individuals working with the new handle, as well as the reduction in the hyperflexion of the wrist. Compared with the conventional handle, electromyography reveals that no muscle load is increased when working with the new handle. The results of the subjective survey show that volunteers expressed a significant preference for the new handle, demonstrating an improvement in the ergonomic characteristics.

Using infrared imaging for assessment of muscular activity in the forearm of surgeons in the performance of laparoscopic tasks.

Surgeons working in laparoscopic surgery are subjected to hard working conditions because of the poor ergonomic characteristics of the workplace. The improvement in the working conditions requires the use of reliable techniques for the assessment of muscular activity. In this article infrared imaging is used and compared with electromyography for the evaluation of muscle activity in the performance of laparoscopic surgical tasks. Electromyography has been widely used for the evaluation of the electrical activity produced by the muscles in the performance of surgery. On the contrary, infrared imaging is an innovative technique that has not been sufficiently explored. An experimental evaluation was carried out using a thermography camera and recording the infrared images from volunteers in different tests. Pearson's correlation was obtained between the electromyography and thermographic measurements in two stages: Endurance Stage (best value: ρ = 0.8401 with p < 0.01) and Surgical Task (best value: ρ = 0.8309 with p < 0.01). The article demonstrates that infrared imaging is a valuable technique for the evaluation of muscle activity in laparoscopic surgery, and it can be compared with electromyography. The main advantages of infrared imaging are that it allows remote measurement and provides activity information in the whole area of interest. However, drawbacks such as delayed response of the infrared imaging due to thermal conductivity of the skin should be considered. Electromyography only provides information in the location of the electrodes, but it is a real-time response. For these reasons, the techniques complement each other.

A study of the prevalence of musculoskeletal disorders in surgeons performing minimally invasive surgery.

INTRODUCTION: Minimally invasive surgery (MIS) has shown significant benefits for patients and healthcare systems. However, due to the poor ergonomic adaptation of operating rooms and surgical instruments, most surgeons suffer from pain caused by musculoskeletal disorders (MSDs). METHODS: A descriptive survey on MIS surgeons working in different surgical specialties has been carried out in Hospital Valdecilla (Spain). The aim is to determine the prevalence of MSDs using a personal interview and the standardized Nordic questionnaire. The study determines the prevalence of MSDs in different parts of the body and their relationship with epidemiological and labor variables. A questionnaire was filled out by 129 surgeons. RESULTS: 90% of surgeons reported MSDs. The higher prevalence appears in the most experienced surgeons. The most affected zones are the lower back (54%), neck (51%), upper back (44%), lower extremities (42%), right shoulder (29%) and right hand (28%). CONCLUSIONS: The prevalence of MSDs is higher in MIS surgeons than in any other occupational group. The most vulnerable group is experienced surgeons and there is a potential risk that symptoms will be increased in the future. Muscle strength is revealed as a protective factor against MSDs.

Use of the Learning Curve-Cumulative Summation Test for Leopold Maneuvers Assessment in a Simulator: A Pilot Study.

INTRODUCTION: Simulation enables medical students to practice clinical skills in a safe environment. Graduates in medicine must be able to correctly perform an examination on a pregnant woman using Leopold maneuvers. Learning curves-cumulative summation (LC-CUSUM) may help determine when the student has achieved a specific skill. Our objective was to perform the LC-CUSUM test regarding the ability of students to correctly carry out Leopold maneuvers; a pregnancy simulator was used, transferring the results to a clinical setting. METHODS: Five medical students were trained to carry out Leopold maneuvers using the simulator. Each student performed maneuvers for 50 cases of different fetus positions; a LC-CUSUM was plotted for each student. Afterward, the students performed the Leopold maneuvers on 5 pregnant women. RESULTS: Of the 5 students, 3 achieved a level of proficiency; the attempts needed for reaching this level were 13, 13, and 37, respectively. The other 2 students did not reach proficiency level. Of the students who became successfully proficient with the simulator, one of them attained a 100% success rate in pregnant patients, whereas the other two had success rates of 80%. The students who did not achieve a level of competency with the simulator had only a 60% success rate with patients. CONCLUSIONS: Because of the differences observed between students in the number of attempts needed for achieving proficiency in Leopold maneuvers, we believe that each student should build his/her own learning curve. Achieving competency in carrying out Leopold maneuvers using the simulator could be transferable to patients.

Dietary indexes, food patterns and incidence of metabolic syndrome in a Mediterranean cohort: The SUN project.

BACKGROUND & AIMS: We prospectively assessed the association between adherence to several a priori defined healthy food patterns and risk of metabolic syndrome (MetS). METHODS: We assessed 6851 participants of a Spanish dynamic prospective cohort of university graduates, initially free of any MetS-specific definition criteria, and followed-up for a median of 8.3 years. We calculated the adherence to thirteen different a priori defined food patterns or dietary indexes. MetS was classified according to the updated harmonizing criteria. We estimated multivariable-adjusted Incidence Rate Ratios (IRR) of metabolic syndrome and their 95% Confidence Intervals (95% CI), using Poisson regression models. RESULTS: The cumulative incidence of MetS was 5.0%. Moderate adherence to the Pro-Vegetarian Diet (PVEG) was significantly associated with a lower risk for developing MetS (IRR = 0.75, 95% CI = 0.59-0.97). Among women, an inverse association with the PVEG was significant not only for a moderate adherence (IRR = 0.54, 95% CI = 0.36-0.82), but also for higher adherence (IRR = 0.63, 95% CI = 0.43-0.93). A higher adherence to the Dietary Approaches to Stop Hypertension (DASH) diet showed an inverse association with the MetS among participants, but only if they had low alcohol intake (RR = 0.41, 95% CI = 0.20-0.85). CONCLUSIONS: Our findings support the adoption of a PVEG dietary pattern for the reduction of MetS risk. The same statement can be applied in relation to the DASH diet, insofar a limited consumption of alcoholic beverages is also maintained.

Design and evaluation of a new ergonomic handle for instruments in minimally invasive surgery.

BACKGROUND: Laparoscopic surgery techniques have been demonstrated to provide massive benefits to patients. However, surgeons are subjected to hardworking conditions because of the poor ergonomic design of the instruments. In this article, a new ergonomic handle design is presented. This handle is designed using ergonomic principles, trying to provide both more intuitive manipulation of the instrument and a shape that reduces the high-pressure zones in the contact with the surgeon's hand. MATERIALS AND METHODS: The ergonomic characteristics of the new handle were evaluated using objective and subjective studies. The experimental evaluation was performed using 28 volunteers by means of the comparison of the new handle with the ring-handle (RH) concept in an instrument available on the market. The volunteers' muscle activation and motions of the hand, wrist, and arm were studied while they performed different tasks. The data measured in the experiment include electromyography and goniometry values. RESULTS: The results obtained from the subjective analysis reveal that most volunteers (64%) preferred the new prototype to the RH, reporting less pain and less difficulty to complete the tasks. The results from the objective study reveal that the hyperflexion of the wrist required for the manipulation of the instrument is strongly reduced. CONCLUSIONS: The new ergonomic handle not only provides important ergonomic advantages but also improves the efficiency when completing the tasks. Compared with RH instruments, the new prototype reduced the high-pressure areas and the extreme motions of the wrist.

Enhanced removal of a pesticides mixture by single cultures and consortia of free and immobilized Streptomyces strains.

Pesticides are normally used to control specific pests and to increase the productivity in crops; as a result, soils are contaminated with mixtures of pesticides. In this work, the ability of Streptomyces strains (either as pure or mixed cultures) to remove pentachlorophenol and chlorpyrifos was studied. The antagonism among the strains and their tolerance to the toxic mixture was evaluated. Results revealed that the strains did not have any antagonistic effects and showed tolerance against the pesticides mixture. In fact, the growth of mixed cultures was significantly higher than in pure cultures. Moreover, a pure culture (Streptomyces sp. A5) and a quadruple culture had the highest pentachlorophenol removal percentages (10.6% and 10.1%, resp.), while Streptomyces sp. M7 presented the best chlorpyrifos removal (99.2%). Mixed culture of all Streptomyces spp. when assayed either as free or immobilized cells showed chlorpyrifos removal percentages of 40.17% and 71.05%, respectively, and for pentachlorophenol 5.24% and 14.72%, respectively, suggesting better removal of both pesticides by using immobilized cells. These results reveal that environments contaminated with mixtures of xenobiotics could be successfully cleaned up by using either free or immobilized cultures of Streptomyces, through in situ or ex situ remediation techniques.

The use of volcanic soil as mineral landfill liner--III. Heavy metals retention capacity.

The volcanic soil of Southern Chile was tested for its heavy metal retention capacity. The maximum uptakes for CrO4(2-) (CrVI), Cu(2+), Zn(2+) and Pb(2+) were determined to be 2.74, 5.32, 5.86 and 7.44 mg g(-1), respectively. At a slightly alkaline pH value (7.5), it seems that a precipitation-adsorption process was responsible for the Cu(2+) and Zn(2+) uptake onto volcanic soil. All the determined values are of the same order of magnitude as natural zeolites heavy metals adsorption capacities. In addition, the heavy metals diffusion model through a 1 m volcanic soil mineral liner shows breakthrough times of 21.6, 10.2 and 8.9 years, for Pb(2+), Zn(2+) and Cu(2+), respectively, confirming the trend obtained in the adsorption isotherms. The natural volcanic soil of Southern Chile is an interesting material for possible use as landfill mineral basal sealing. It has an appropriate sealing potential (average Kf value of 5.85 x 10(-9) m s(-1)) and a heavy metals retention capacity comparable with natural zeolites. About two-thirds of the agricultural land in Chile (approximately 0.4 million km2) is derived from volcanic ash, suggesting an important soil volume for future landfill projects, that could be obtained in sufficient quantities from urban building activities.

Sensitivity of bile acid transport by organic anion-transporting polypeptides to intracellular pH.

We investigated the influence of intracellular pH (pHi) on [14C]-glycocholate (GC) uptake by human hepatoblastoma HepG2 cells that express sodium-independent (mainly OATP-A and OATP-8), but not sodium-dependent, GC transporters. Replacement of extracellular sodium by choline (Chol) stimulated GC uptake but did not affect GC efflux from loaded cells. Amiloride or NaCl replacement by tetraethylammonium chloride (TeACl) or sucrose also increased GC uptake. All stimulating circumstances decreased pHi. By contrast, adding to the medium ammonium or imidazole, which increased pHi, had no effect on GC uptake. In Chinese hamster ovary (CHO) cells expressing rat Oatp1, acidification of pHi had the opposite effect on GC uptake, that is, this was reduced. Changes in extracellular pH (pHo) between 7.40 and 7.00 had no effect on GC uptake at pHi 7.30 or 7.45 when pHopHi. Inhibition was not proportional to the pHo-pHi difference. Intracellular acidification decreased V(max), but had no effect on K(m). In sum, sodium-independent GC transport can be affected by intracellular acidification, possibly due both to modifications in the driving forces and to the particular response to protonation of carrier proteins involved in this process.

Relationship between tumor cell load and sensitivity to the cytostatic effect of two novel platinum-bile acid complexes, Bamet-D3 and Bamet-UD2.

Based on the organotropic characteristics of bile acids towards the liver and the intestine, two novel compounds of the Bamet family, containing at least one bile acid moiety bound to platinum(II), have been synthesized and their cytostatic effect compared to their ability to become accumulated in tumor cells of hepato-intestinal origin. Bamet-UD2 [cis-diammine-bis-ursodeoxycholic platinum(II)] induced a marked inhibition of cell growth, which was more marked in human hepatoblastoma HepG2 and mouse hepatoma Hepa 1-6 cells than in rat hepatoma McA-RH7777 and human colon adenocarcinoma LS 174T cells. This effect was similar to that observed for cisplatin and stronger than that previously reported for other members of this family, such as Bamet-H2 and Bamet-R2. By contrast, Bamet-D3 [(N'N'' cis-dichloro N(3-3-amminepropylammine)propyl) glycocholamide platinum (II)] was only effective in reducing growth in human hepatoblastoma HepG2 cells. Because the in vitro DNA-reactivity was approximately 5-fold higher for Bamet-D3 than for Bamet-UD2, an additional cause for the difference in their cytostatic abilities was sought, investigating the relationship between cell load and the cytostatic effect of the drugs. Drug uptake by two cell lines, Hepa 1-6 and HepG2, with different sensitivities to these compounds was measured. The cellular uptake of Bamet-D3 and Bamet-UD2 was several-fold higher than that of cisplatin. No significant difference in the amount of both drugs taken up by these cell types was found. A study on sodium-dependency and substrate specificity indicated that Hepa 1-6 cells take up Bamet-D3 and Bamet-UD2 via similar mechanism(s), whereas these compounds do not seem to share the uptake pathways in HepG2 cells. Measurement of cell viability by formazan formation from tetrazolium salts and by neutral red uptake, after short-term (6 h) exposure to the desired drug, indicated that no acute toxic effect occurs in the presence of cisplatin or Bamet-D3 in either HepG2 or Hepa 1-6 cells. By contrast, in both cell lines Bamet-UD2 induced acute cell toxicity in a dose-dependent fashion. In sum, the results indicate that tumor cells efficiently take up these two novel compounds of the Bamet family. Although the exact uptake mechanism remains unknown, it seems to be dependent on the cell type. However, the cell load does not account for the differences in the anti-proliferative properties of the drugs. The strong and promising cytostatic activity of Bamet-UD2 is additionally related to its ability, absent in Bamet-D3, to acutely alter cellular functions other than proliferation.

Changes in the pool of bile acids in hepatocyte nuclei during rat liver regeneration.

BACKGROUND/AIMS: To investigate changes in nuclear bile acids (BAs) during rat liver regeneration. METHODS: Nuclei were isolated from control rat livers and after two-thirds partial hepatectomy (PH). BAs in bile, liver homogenate and nuclei were measured by gas chromatography-mass spectrometry. Nuclear translocation of radiolabeled BAs was determined using fresh isolated hepatocytes from control donors. RESULTS: Liver BA concentrations were transiently reduced after PH. Relative increases in: -MCA at 1 day, deoxycholic acid at 7 days and cholic acid (CA) at 3 and 14 days were found. Nuclear BAs accounted for <0.5% of liver BAs. Contamination with cytosolic BAs during nuclei isolation was <4%. Unconjugated- and conjugated-CA were able to reach the nucleus with similar efficiency. The pattern of nuclear BAs--CA (80%) and ursodeoxycholic acid (UDCA) (8.5%) being the most abundant--did not match that found in liver or bile. A transient decrease in CA/UDCA ratio, in absence of significant change in total BA content, was observed in nuclei after PH. "Flat" BA species were only detected in homogenate, but not in nuclei, at 1 day after PH. CONCLUSIONS: BA pool in nuclei of rat hepatocytes, whose composition is different to that of total liver BA pool, undergoes important changes during liver regeneration.

Evidence for dual effects of DNA-reactive bile acid derivatives (Bamets) on hepatitis B virus life cycle in an in vitro replicative system.

A liver targeting strategy to direct antiviral drugs toward hepatitis B virus (HBV) was investigated. As model drugs we used cisplatin-bile acid derivatives (Bamets) to determine the production of virions by HBV-transfected hepatoblastoma cells (HepG2 2.2.15). Drug uptake was determined using flameless atomic absorption spectrometry to measure platinum cell contents. Cytotoxic effect was determined by formazan formation and neutral red uptake tests. The release of viral surface protein was evaluated by ELISA. The abundance of HBV-DNA in the medium was determined by quantitative real-time PCR and its structure by Southern blot analysis. The uptake of Bamets by HepG2 2.2.15 cells was higher than that of cisplatin. At concentrations lower than 10 microM, distinct Bamets have no toxic effect on host cells, whereas cisplatin dramatically reduced cell viability at concentrations higher than 1 microM. All the drugs tested inhibited the release of viral proteins to the medium, but induced a marked and progressive dose-dependent increase in the amount of viral DNA in the medium. This was mainly due to the release of short fragments of HBV-DNA in the case of cisplatin. On the contrary, Bamets induced an enhanced release of circular forms of HBV-DNA. These findings suggest the existence of a dual effect of Bamets on HBV life-cycle by enhancing the production of DNA replicative intermediates but reducing the secretion of complete virions. Altogether these characteristics recommend consideration of these compounds as a useful experimental tool in the investigation of novel liver targeted therapeutic agents based on bile acid derivatives for the treatment of HBV infections, or to carry out further studies on the HBV life cycle.