Mechanical Touch Research Articles

Ion Channel Modulation in Spinal/Trigeminal Synaptic Plasticity

Ion Channel Modulation in Spinal/Trigeminal Synaptic Plasticity

Protracted delay in taste sensation recovery after surgical lingual nerve repair: a case report

IntroductionLingual nerve injury is sometimes caused by dental treatment. Many kinds of treatment have been reported, but many have exhibited poor recovery. Here the authors report changes in somatosensory and chemosensory impairments during a long-term observation after lingual nerve repair.Case presentationA 30-year-old Japanese woman claimed dysesthesia and difficulty eating. Quantitative sensory test results indicated complete loss of sensation in the right side of her tongue. She underwent a repair surgery involving complete resection of her lingual nerve using a polyglycolic acid tube containing collagen 9 months after the injury. A year after the operation, her mechanical touch threshold recovered, but no other sensations recovered. Long-term observation of her somatosensory and chemosensory function after the nerve repair suggested that recovery of taste sensation was greatly delayed compared with that of somatosensory function.ConclusionThis case shows characteristic changes in somatosensory and chemosensory recoveries during 7 postoperative years and suggests that taste and thermal sensations require a very long time to recover after repair surgery.

Criterion for determining the prognosis of reduction in the mechanical touch threshold caused by trigeminal peripheral nerve injury

Criterion for determining the prognosis of reduction in the mechanical touch threshold caused by trigeminal peripheral nerve injury

Study on Electromagnetic Repulsion Suspension of CNC Machine Guide System

Magnetic suspension technology is used in CNC machine tool. The guide which uses the electromagnetic force is suspended in the air without mechanical touch. There is no mechanical contact with the supporting components. It can eliminate friction and wear. Magnetic suspension structure guide can achieve fast and precise position, and increase the productivity of the equipment substantially. Magnetic suspension structure guide has a lot of significant advantages. The magnetic suspension rail can ensure the high positioning accuracy of machine tools platform from the structure, and reduce the inertial mass of the drive system, Improve platform mobile frequency response. Magnetic suspension system has both the advantages of Energy-saving and environmental protection. The magnetic suspension support extends the useful life of equipment, improves the operating conditions of equipment. It has broad application prospects in terms of transportation, machinery, appliances, materials, metallurgy, electrical, Material.

STR-33, a Novel G Protein-coupled Receptor That Regulates Locomotion and Egg Laying in Caenorhabditis elegans

Despite their predicted functional importance, most G protein-coupled receptors (GPCRs) in Caenorhabditis elegans have remained largely uncharacterized. Here, we focused on one GPCR, STR-33, encoded by the str-33 gene, which was discovered through a ligand-based screening procedure. To characterize STR-33 function, we performed UV-trimethylpsolaren mutagenesis and isolated an str-33-null mutant. The resulting mutant showed hypersinusoidal movement and a hyperactive egg-laying phenotype. Two types of egg laying-related mutations have been characterized: egg laying-deficient (Egl-d) and hyperactive egg laying (Egl-c). The defect responsible for the egg laying-deficient Egl-d phenotype is related to Gα(q) signaling, whereas that responsible for the opposite, hyperactive egg-laying Egl-c phenotype is related to Gα(o) signaling. We found that the hyperactive egg-laying defect of the str-33(ykp001) mutant is dependent on the G protein GOA-1/Gα(o). Endogenous acetylcholine suppressed egg laying in C. elegans via a Gα(o)-signaling pathway by inhibiting serotonin biosynthesis or release from the hermaphrodite-specific neuron. Consistent with this, in vivo expression of the serotonin biosynthetic enzyme, TPH-1, was up-regulated in the str-33(ykp001) mutant. Taken together, these results suggest that the GPCR, STR-33, may be one of the neurotransmitter receptors that regulates locomotion and egg laying in C. elegans.

Kicking and biting behavioral responses toward mechanical touch stimuli for evaluation of aggravation and amelioration of stress disorder

Kicking and biting behavioral responses toward mechanical touch stimuli for evaluation of aggravation and amelioration of stress disorder

Perceived touch location is coded using a gaze signal

The location of a touch to the skin, first coded in body coordinates, may be transformed into retinotopic coordinates to facilitate visual-tactile integration. In order for the touch location to be transformed into a retinotopic reference frame, the location of the eyes and head must be taken into account. Previous studies have found eye position-related errors (Harrar and Harris in Exp Brain Res 203:615-620, 2009) and head position-related errors (Ho and Spence Brain Res 1144:136-141, 2007) in tactile localization, indicating that imperfect versions of eye and head signals may be used in the body-to-visual coordinate transformation. Here, we investigated the combined effects of head and eye position on the perceived location of a mechanical touch to the arm. Subjects reported the perceived position of a touch that was presented while their head was positioned to the left, right, or center of the body and their eyes were positioned to the left, right, or center in their orbits. The perceived location of a touch shifted in the direction of both head and the eyes by approximately the same amount. We interpret these shifts as being consistent with touch location being coded in a visual reference frame with a gaze signal used to compute the transformation.

A study on laser touch dressing of electroplated diamond wheels using pulsed picosecond laser sources

An investigation to explore the possibility of touch dressing of electroplated diamond wheels using a pulsed picosecond laser (ps-laser) beam (Yb:YAG) is presented. The laser beam is irradiated on the wheel to cut the diamond grains within a defined grain protrusion without any thermal damage on the nickel bond. The laser parameters were systematically varied to achieve a reliable touch dressing process. The microscopic investigations prove thermal damages neither on the diamond grain nor on the bond. Series of SiC wheel dressing experiments were carried out to compare mechanical touch dressing of the electroplated diamond wheel with laser dressed wheels.

Squeeze me, but don't tease me: Human and mechanical touch enhance visual attention and emotion discrimination

Being touched by another person influences our readiness to empathize with and support that person. We asked whether this influence arises from somatosensory experience, the proximity to the person and/or an attribution of the somatosensory experience to the person. Moreover, we were interested in whether and how touch affects the processing of ensuing events. To this end, we presented neutral and negative pictures with or without gentle pressure to the participants' forearm. In Experiment 1, pressure was applied by a friend, applied by a tactile device and attributed to the friend, or applied by a tactile device and attributed to a computer. Across these conditions, touch enhanced event-related potential (ERP) correlates of picture processing. Pictures elicited a larger posterior N100 and a late positivity discriminated more strongly between pictures of neutral and negative content when participants were touched. Experiment 2 replicated these findings while controlling for the predictive quality of touch. Experiment 3 replaced tactile contact with a tone, which failed to enhance N100 amplitude and emotion discrimination reflected by the late positivity. This indicates that touch sensitizes ongoing cognitive and emotional processes and that this sensitization is mediated by bottom-up somatosensory processing. Moreover, touch seems to be a special sensory signal that influences recipients in the absence of conscious reflection and that promotes prosocial behavior.

Quantitative analysis of kicking and biting behavioral responses to mechanical touch stimuli in socially isolated mice

Quantitative analysis of kicking and biting behavioral responses to mechanical touch stimuli in socially isolated mice

Anti-inflammatory effects of phosphatidylcholine in neutrophil leukocyte-dependent acute arthritis in rats

We investigated the effects of exogenous phosphatidylcholine (PC) and non-steroidal diclofenac supplementation on polymorphonuclear cell influx in carrageenan-induced arthritis in rats. The microcirculatory consequences were evaluated by a novel method developed for direct intravital microscopic observation of the synovial membrane. Arthritis was induced by injection of a mixture of 2% λ-carrageenan and 4% kaolin into the knee joints and the animals were treated orally with PC (150 mg/kg twice daily), sodium diclofenac (0.5 mg/kg twice daily) or saline vehicle. Intravital videomicroscopy was used to investigate the leukocyte-endothelial interactions directly in the synovial membrane at 6 h after the challenge. The inflammation–induced thermal and mechanical secondary hyperalgesic reactions were assessed at 24 h, and the knee volume changes at 48 h after the insult. The development of arthritis was accompanied by a significant increase in the number of adherent leukocytes in the synovial postcapillary venules, but this increase was reduced significantly (by ∼ 40%) by PC, and slightly (by 22%) by diclofenac treatment. The perivascular infiltration of the neutrophil leukocytes and the intercellular adhesion molecule-1 (ICAM-1) expressions were reduced only by PC treatment. The significant decrease (45%) in the thermal nociceptive latency, the 3-fold increase in the mechanical touch sensitivity and the knee cross-sectional area (which was increased by 35% by the arthritis induction) were significantly ameliorated by both treatments. The present study demonstrated the anti-inflammatory effects of PC in experimental arthritis. The therapeutic potential may be linked to the reduction of neutrophil leukocyte-mediated microcirculatory inflammatory reactions.

Potentiation of Local Anesthetic Activity of Neosaxitoxin with Bupivacaine or Epinephrine: Development of a Long-Acting Pain Blocker

Local anesthetics effectively block and relieve pain, but with a relatively short duration of action, limiting its analgesic effectiveness. Therefore, a long-acting local anesthetic would improve the management of pain, but no such agent is yet available for clinical use. The aim of this study is to evaluate the potentiation of the anesthetic effect of neosaxitoxin, with bupivacaine or epinephrine in a randomized double-blind clinical trial. Ten healthy males were subcutaneously injected into the left and right forearms with a randomized pair of the following treatments: (i) bupivacaine (5 mg); (ii) neosaxitoxin (10 microg); (iii) neosaxitoxin (10 microg) plus bupivacaine (5 mg), and (iv) neosaxitoxin (10 microg) plus epinephrine (1:100.000), but all participant received all four formulations (in 2 ml; s.c.), with 1 month elapsing between the two round of experiments. A validated sensory and pain paradigm was used for evaluating the effect of the treatment 0-72 h after the injections, measuring sensory, pain, and mechanical touch perception threshold. The duration of the effect produced by combined treatments was longer than that by the single drugs. In conclusion, bupivacaine and epinephrine potentiate the local anesthetic effect of neosaxitoxin in humans when co-injected subcutaneously. The present results support the idea that neosaxitoxin is a new long-acting local pain blocker, with highly potential clinical use.

Behavioural and histological observations of sensory impairment caused by tight ligation of the trigeminal nerve in mice

Dental treatments sometimes cause sensory impairment, especially in the region innervated by the third division of the trigeminal nerve. The most frequent symptoms are loss of sensation and abnormal sensation. Although most studies have addressed the neuropathic symptom “allodynia” using experimental animal models of the infraorbital nerve, there is little information regarding the sensory impairment that frequently occurs clinically. Therefore, different experimental models are required to clarify the mechanisms of the clinical effects, and previous experimental models have been limited to rats. Here, we report a sensory impairment model in mice whose mechanical touch threshold increased after tight ligation of the mental nerve. Habituation before surgery by mechanical touching of the face enabled us to observe the long-term chronological changes in sensation. The mechanical touch thresholds within the mental nerve region were measured for 70 postoperative (PO) days. Changes in the distribution of substance P (SP) were evaluated by immunohistochemistry to clarify the involvement of axonal flow in the sensory impairment and its recovery. The mechanical touch thresholds transiently increased by PO days 2–3, but decreased to the preoperative levels at around PO day 14. Apparent SP immunoreactivity was recognizable on the medial side to the ligation at PO days 2–3 and disappeared at PO day 7. These behavioural and immunohistochemical changes appeared to exhibit similar time courses, suggesting a possible relationship between them. Therefore, we suggest that our experimental mouse model could represent a new model for clarifying the mechanism of the sensory impairment caused by peripheral nerve injury.

Permanent stigma closure in Bignoniaceae: Mechanism and implications for fruit set in self-incompatible species

The Bignoniaceae possess sensitive bilobate stigmas that close after stimulation. We determined factors involved in stigma closure and reopening in four species of Bignoniaceae from the National Parks of Catimbau, Northeastern Brazil ( Anemopaegma laeve, Arrabidaea limae, Jacaranda rugosa and Tabebuia impetiginosa). The study showed that any mechanical touch promoted the stigmatic closure. Only the deposition of viable con-specific pollen (self- and cross-pollen), however, maintained stigmas permanently closed. In Arrabidaea limae part of the stigmas reopened after self- and cross-pollination. After mechanical stimulation, deposition of pollen from other plant species, of dead con-specific pollen or of sand, the stigma lobes opened again after 38 to 68 min. The definitive closure may have a negative effect on the reproductive success of the involved plants, because the stigmas are permanently unavailable for pollen deposition. In self-incompatible species with mass-flowering blooming pattern, where pollinators promote high levels of geitonogamy, definitive stigma closure causes low fruit set.

Neosaxitoxin as a Local Anesthetic

Neosaxitoxin is a phycotoxin that reversibly blocks the voltage-gated sodium channels at the neuronal level. Its activity results in blocking the axonal conduction, stopping the propagation of the nerve impulse. The objective of the present work was to evaluate neosaxitoxin as a local anesthetic in a human trial. The authors conducted a randomized, double-blind, placebo-controlled trial with 10 healthy volunteers. Subcutaneous injections were made in the middle posterior skin of the calf: one leg received 50 microg neosaxitoxin, and the contra-lateral leg received placebo. The anesthetic effect was evaluated using a standardized human sensory and pain model. TSA II Neurosensory Analyzer (Medoc Ltd, Minneapolis, MN) and von Frey technique were used to evaluate five parameters: sensory threshold for warm and cold, pain thresholds for heat and cold, and mechanical touch perception threshold. Measurements were made 0, 1, 3, 6, 9, 12, 16, 24, and 48 h after the injections. For all the patients, effective and complete blocking of the evaluated parameters was obtained. As the blocking began to revert gradually, heat pain was the first to return to normal values after 3 h. Cold pain was the longest sensation abolished, achieving 24 h of blockade. The toxin was undetected in blood and urine samples. No adverse reactions to neosaxitoxin were detected. Neosaxitoxin showed an effective local anesthetic effect when injected in the subcutaneous plane. The efficacy of a 50-microg dose of neosaxitoxin was shown. This is the first report of neosaxitoxin as a local anesthetic in a human trial.

This Month in Anesthesiology

This Month in Anesthesiology

High-accuracy contouring using projection moiré

Shadow and projection moiré are the oldest forms of moiré to be used in actual technical applications. In spite of this fact and the extensive number of papers that have been published on this topic, the use of shadow moiré as an accurate tool that can compete with alternative devices poses very many problems that go to the very essence of the mathematical models used to obtain contour information from fringe pattern data. In this paper some recent developments on the projection moiré method are presented. Comparisons between the results obtained with the projection method and the results obtained by mechanical devices that operate with contact probes are presented. These results show that the use of projection moiré makes it possible to achieve the same accuracy that current mechanical touch probe devices can provide.

Using the Modified Hypo-Osmotic Swelling Test for the Selection of Immotile Testicular Spermatozoa in ICSI—A Randomized Controlled Study

Various methods have been described for the selection of viable among immotile testicular spermatozoa prior to ICSI in cases of total absence of motility. These include the addition of pentoxifyllin, the mechanical touch technique, performing the hypo-osmotic swelling (HOS) test (Jeyendran solution) as well as the modified HOS test (50% culture medium + 50% Millipore grade water). However, these reports have not been confirmed by randomized controlled studies (RCTs). The aim of this work was to conduct a RCT to evaluate the use of the modified HOS test for the selection of viable but immotile spermatozoa in cases of ICSI using testicular sperm (ICSI-TeSE). A randomized controlled trial. All couples treated in our center between January 2002 and August 2004 by ICSI using testicular sperm due to azoospermia (n= 316) were eligible for the study. They included 81 couples whose testicular biopsy (fresh or frozen) revealed total absence of motility and these were included in this study in their first cycle of treatment. The couples were randomized at the time of ICSI using a closed envelope system and allocated to one of two groups. In patients belonging to the first group (no HOS test group), selection of spermatozoa for ICSI was performed on the basis of morphology, while in the second group (HOS test group), the modified HOS was performed and only reactive spermatozoa were used for the injection. The modified HOS test entails placing the immotile spermatozoa in a microdroplet consisting of a 50% culture medium and 50% Millipore grade water. After a maximum of 10 seconds, viable spermatozoa, recognized by their curved or swollen tails, were selected and transferred into another microdroplet of HEPES-buffered medium where they were washed 3 times to re-equilibrate them osmotically, before being transferred to the PVP microdroplet. The tails of the all spermatozoa were crushed before the injection step. Group A consisted of 36 cycles, while group B consisted of 45 cycles. The fertilisation rate was 40.5% in the HOS test group compared to 18.7% in the no HOS test group (P<0.0001). The clinical pregnancy rate was 26.7% in the HOS test group compared to 5.6% in the no HOS test group (P< 0.05). The delivery/ongoing pregnancy rate was 20% in the HOS test group compared to 2.8% in the non-HOS group (P< 0.05). The implantation rate was 22.8% in the HOS test group compared to 5% in the no HOS test group (P< 0.05). The selection of viable among immotile testicular spermatozoa prior to ICSI using the modified HOS test increases the fertilisation rate, the pregnancy rate, the ongoing pregnancy rate and the implantation rate significantly.

Reply: Pregnancy with frozen-thawed and fresh testicular biopsy after motile and immotile sperm microinjection, using the mechanical touch technique to assess viability

Reply: Pregnancy with frozen-thawed and fresh testicular biopsy after motile and immotile sperm microinjection, using the mechanical touch technique to assess viability

Pregnancy with frozen-thawed and fresh testicular biopsy after motile and immotile sperm microinjection, using the mechanical touch technique to assess viability

There are few reports of pregnancy using immotile sperm, and none using a purely mechanical assessment of viability.In this pilot study, we retrospectively analysed 66 cycles in 61 patients with determinant male factor, recording rates of fertilization, implantation, normal pregnancy and take-home babies achieved with ICSI. Sperm selection was based on morphologically normal appearance under the inverted microscope. Viability of immotile spermatozoa was assessed by the mechanical touch technique to observe tail flexibility and tail shape recovery.Of 17 ICSI cycles using frozen-thawed testicular sperm, six microinjected with immotile and 11 with motile sperm, we achieved fertilization rates of 65.7 and 74.3%, respectively, and five pregnancies (two and three, respectively). Of 49 ICSI cycles using fresh testicular sperm, 10 microinjected with immotile and 39 with motile sperm, we achieved fertilization rates of 73.4 and 64.4%, respectively, and 12 pregnancies (three and nine, respectively).Immotile (fresh and frozen-thawed) testicular sperm of normal morphological appearance can be used to achieve clinical pregnancy with ICSI. Our results strongly suggest that immotile sperm viability can be assessed by the mechanical touch technique.