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At least 865 records · Page 48Linked to original sources
PubMed2006

A review on reproductive biotechnologies for conservation of endangered mammalian species.

This review describes the use of modern reproductive biotechnologies or assisted reproductive techniques (ART) including artificial insemination, embryo transfer/sexing, in vitro fertilization, gamete/embryo micromanipulation, semen sexing, genome resource banking, and somatic cell nuclear transfer (cloning) in conservation programs for endangered mammalian species. Such biotechnologies allow more offspring to be obtained from selected parents to ensure genetic diversity and may reduce the interval between generations. However, the application of reproductive biotechnologies for endangered free-living mammals is rarer than for endangered domestic breeds. Progress in ART for non-domestic species will continue at a slow pace due to limited resources, but also because the management and conservation of endangered species is biologically quite complex. In practice, current reproductive biotechnologies are species-specific or inefficient for many endangered animals because of insufficient knowledge on basic reproduction like estrous cycle, seasonality, structural anatomy, gamete physiology and site for semen deposition or embryo transfer of non-domestic species.

Animals↗
PubMed2004

Hg2+ and small-sized polyethylene glycols have inverse effects on membrane permeability, while both impair neutrophil cell motility.

Toxic effects after exposure to mercury are well documented in human. Little is, however, known about how Hg(2+) affect host defense in general and neutrophil functions in particular. We show here that exposure of human neutrophils to HgCl(2) dose-dependently impairs chemoattractant-stimulated motility. Long-term exposure (5-10 min) to Hg(2+) yields a rapid influx of extracellular Ca(2+) followed by leakage of cytosolic fluorophores, as assessed using fura-2 and ratio imaging microscopy. The inhibition on motility was partly reversible, since pre-treated neutrophils placed in an Hg(2+)-free environment displayed higher migration rates. The Hg(2+)-induced fluxes were prevented by addition of small-sized polyethylene glycols (PEG 200-400), which also dose-dependently inhibited neutrophil transmigration. Localized, minute micropipette additions of Hg(2+) or PEG caused retraction of the leading edge and redirection of cell migration. Since Hg(2+) increases and PEGs decrease membrane permeability in a partially competitive manner, we suggest that the known aquaporin-inhibitor Hg(2+) alters membrane permeability by affecting the bidirectional flux through the leukocyte aquaporin-9 (AQP9) while small-sized PEGs yield decreased membrane permeability by becoming trapped in the promiscuous channel. The local additions of Hg(2+) or PEG probably force other cell regions to take over from those with blocked AQPs. Hence, the cells turn direction of motility away from the micromanipulator needle.

Actin Cytoskeleton↗
PubMed2006

Simultaneous detection of L-glutamate and nitric oxide from adherently growing cells at known distance using disk shaped dual electrodes.

An ex vivo system for simultaneous detection of nitric oxide (NO) and L-glutamate using integrated dual 250 microm platinum disk electrodes modified individually with suitable sensing chemistries has been developed. One of the sensors was coated with an electrocatalytic layer of Ni tetrasulfonate phthalocyanine tetrasodium salt (Ni-TSPc) covered by second layer of Nafion, which stabilises on the one hand the primary oxidation product NO(+) and prevents interferences from negatively charged compounds such as NO(2)(-). For glutamate determination, the second electrode was modified with a crosslinked redox hydrogel consisting of Os complex modified poly(vinylimidazol), glutamate oxidase and peroxidase. A manual x-y-z micromanipulator on top of an inverted optical microscope was used to position the dual electrode sensor at a defined distance of 5 microm from a cell population under visual control. C6 glioma cells were stimulated simultaneously with bradykinin or VEGF to release NO while KCl was used to invoke glutamate release. For evaluation of the glutamate sensors, in some experiments HN10 cells were used. To investigate the sensitivity and reliability of the system, several drugs were applied to the cells, e.g. Ca(2+)-channel inhibitors for testing Ca(2+)-dependence of the release of NO and glutamate, rotenone for inducing oxidative stress and glutamate antagonists for analysing glutamate release. With these drugs the NO and glutamate release was modulated in a similar way then expected from previously described systems or even in-vivo measurements. We therefore conclude that our system is suitable to analyse stress-induced mechanisms in cell lines.

Animals↗
PubMed2005

Effects of operating conditions on the adhesive strength of Pseudomonas fluorescens biofilms in tubes.

Understanding the mechanical properties of biofilms, especially the force required to disrupt them and remove them from substrata is very important to development of antibiofouling strategies. In this work, a novel micromanipulation technique with a specially designed T-shaped probe has been developed to serve as an experimental means to measure directly the adhesive strength of biofouling deposits on the surface of a glass test stud. The basic principle of this novel technique is to pull away a whole biofilm accumulated on the surface of a glass test stud with T-shaped probe, and to measure simultaneously the force imposed on the biofilm. The adhesive strength between the biofilms and the surface to which they are attached, is defined as the work per unit area required to remove the biofilms from the surface. The biofouling experiments were performed on an elaborate design of a simulated heat exchanger system. A monoculture of Pseudomonas fluorescens was chosen as the fouling microorganism for the laboratory studies. Results indicate that the adhesive strength of the biofilm was affected by the conditions of operation, such as biofilm age, nutrient concentration, suspended cell concentration, pH, surface roughness of the substratum and fluid velocity. As noted, the effect of fluid velocity on the biofilm adhesive strength seemed to overwhelm other factors. At the same operating conditions, the biofilm adhesive strength increased as the fluid velocity increased within the range of 0.6-1.6m/s. In addition, the flow-related biofilm structures were observed that biofilms generally grew as a more compact pattern at the higher fluid velocity. Apparently, the fluid velocity can affect the biofilm structure, which in turn determines the biofilm adhesive strength. The knowledge of the biofilm adhesive strength with associated influences of the operating conditions may be used to define better cleaning procedures.

Bacterial Adhesion↗
PubMed2004

Oxygen tension in the rabbit lens and vitreous before and after vitrectomy.

Oxygen is believed to be one of the potential causative agents for the development of nuclear cataract following vitrectomy. The aim of this study was to determine the partial pressure of oxygen (pO2) in different compartments of the rabbit eye, and to describe the changes following vitrectomy. Twenty-six rabbits (3.5-5.3 kg) were anesthetized and oxygen tension was probed using a fiber-optic oxygen sensor system (optode). A micromanipulator was employed to ascertain the exact position of the probe within the eye. Measurements were taken pre- and post-vitrectomy at several defined positions within the vitreous, the lens and the anterior chamber. Follow-up measurements were performed 2 and 8 weeks after vitrectomy. The contralateral eye served as a control. Measurements in the normal rabbit eye showed that oxygen tension in the globe is asymmetrical with the lowest pO2 in the nucleus of the lens (10.4 mmHg+/-3.0). The region of the lens near the posterior capsule has an oxygen tension close to the values of the vitreous directly behind the posterior capsule (12.4 mmHg+/-3.1). The highest pO2 within the posterior compartment of the eye was measured close to the retinal surface (40-l60 mmHg) depending on neighboring large vessels. The tension drops off rapidly to 20 mmHg some 0.5 mm from the retina. From that position to the posterior surface of the lens there is a shallow gradient of decreasing pO2. Immediately following vitrectomy the pO2 in the BSS replacement varied from ca. 90-140 mmHg, and decreased over approximately 30 min. to levels that were 2-3 times that of normal vitreous. Two weeks after vitrectomy the pO2 values in the lens were 2-3 times as high as in the control eye (p < 0.05). In addition there is no longer a gradient in the vitreous cavity, except close to the retina. Eight weeks after vitrectomy, pO2 levels in the lens were decreased but still remained higher than in the normal eye (13.83 mmHg+/-0.02). The pO2 gradient in the vitreous was not detectable anymore. Overall the results provide evidence that oxygen levels in the lens increase significantly after vitrectomy in rabbits. If this occurs in humans it may contribute to cataract formation following surgery.

Animals↗
PubMed2006

In vivo electrical stimulation of rabbit retina: effect of stimulus duration and electrical field orientation.

Information that defines the depth of activation of retinal neurons is useful in considering strategies for stimulation with a retinal prosthesis, or interpreting the results from human studies that have previously been performed. The purpose of this study was to test the assertion that electrical pulse durations >0.5 msec preferentially stimulate retinal neurons deep to the ganglion cell layer. Thirteen Dutch-belted rabbits (1.2-2.0 kg) were used in this study. A Goldmann-like dome was used to deliver photic stimuli to the retina to measure the electroretinogram (ERG) and the light-induced cortical potential (VECP). Then, a micromanipulator was used to position a 500 microm inner diameter bipolar electrode near the visual streak on the epi-retinal surface. Symmetric biphasic pulses (7-1600 microA; 0.25 msec and 2.0 msec pulses per phase; biphasic pulses delivered at 2 Hz) were delivered to the retina with a current source. Extra-dural electrodes were used to record electrical evoked cortical potentials (EECPs) over the occipital cortex by performing 50 consecutive computer-averaged stimulations. The effect on the EECP of sequential epi-retinal (i.e. return electrode on epi-retinal surface) vs. trans-retinal (i.e. return electrode behind sclera) stimulation was compared. The effect upon the ERG, VECP and EECP was then assessed after 2,3,dihydroxy-6-nitro-7-sulfamoyl-benzo-f-quinoxaline (NBQX) at 112 microM concentration, d-2-amino-7-phosphonoheptanoic acid (D-AP7) at 1200 microM concentration, and l-amino-4-phosphonobutyrate (APB) at 300 microM concentration were delivered into the vitreous cavity to selectively block neuronal input to the retinal ganglion cells. Median values were reported. The amplitudes of the light-induced ERG and VECP were markedly reduced by instillation of the intra-vitreal synaptic blocking drugs. By comparison, pharmacological blockade of input to the retinal ganglion cells did not significantly alter the threshold charge or amplitude of the electrically-induced cortical responses (P>0.05). For the electrical stimuli, there was no significant difference in threshold charge for the EECP for epi-retinal vs. trans-retinal stimulation (P>0.05). The amplitude of the EECP increased linearly with increasing charge using both 0.25 msec and 2.0 msec pulses, even after synaptic blockade of input to the ganglion cells. The lack of obvious degradation of cortical amplitudes after drug instillation indicates that neurons of the middle retina are not being preferentially driven with epi-retinal stimulation, at least not with stimulus pulses up to 2.0 msec in duration. This conclusion is in contrast to prior evidence that 2.0 msec pulses would preferentially stimulate deeper retinal neurons, specifically the bipolar cells. Based upon our own observations in other studies, we believe that preferential stimulation of the middle retina in fact can be achieved by epi-retinal stimulation, by using pulse durations at least 5 times longer than those used in this study.

2-Amino-5-phosphonovalerate↗
PubMed2004

Region-specific cell grafting into cervical and lumbar spinal cord in rat: a qualitative and quantitative stereological study.

In the present study, we have characterized an atraumatic grafting technique which permits multiple, segmental, and lamina-specific injections into cervical or lumbar spinal cord. Cell injections were performed in spinally mounted rats of different ages and spinal cord size, using a micromanipulator and glass microcapillary connected to a digital microinjector. For grafting, we used human neuroteratoma (hNT) cells, BrdU-labeled rat spinal precursors or primary embryonic spinal cord neurons isolated from E14 spinal cord of the eGFP+ rat. Systematic quantification of grafted cells was performed using stereological principles of systematic random sampling and semi-automated optical Disector software. Volume reconstruction was performed using serial sections from grafted areas and custom-developed software (Ellipse) which permits "two reference points" semi-automated alignment of images, as well as volume reconstruction and calculation. By coupling these techniques, it is possible to achieve a relatively precise and atraumatic cell delivery into multiple spinal cord segments and specific spinal laminae. Consistency of the multiple grafts position in the targeted laminar areas was verified by a systematic volume reconstruction. Good survival of implanted cells for the three different cell lines used indicate that this grafting technique coupled with a systematic analysis of the individual grafting sites can represent a valuable implantation-analytical system.

Animals↗
PubMed2004

Pregnancy from intracytoplasmic sperm injection of a sperm head and detached tail.

OBJECTIVE: To evaluate sperm ultrastructure and the efficacy of intracytoplasmic sperm injection (ICSI) with careful positioning of the sperm midpiece next to the sperm head in a patient with easily decapitated sperm syndrome. DESIGN: In vitro fertilization case report with retrospective sperm ultrastructure analysis. SETTING: In vitro fertilization clinic and andrology laboratory. PATIENT(S): A couple seeking treatment for diminished ovarian reserve and male factor infertility using donor oocyte IVF. INTERVENTION(S): Motile sperm inadvertently decapitated during micromanipulation were used for a modified ICSI procedure in which the midpiece was carefully positioned proximal to the sperm head. Sperm were also analyzed by transmission electron microscopy (TEM). MAIN OUTCOME MEASURE(S): Fertilization rate, embryo development, pregnancy, and the incidence of normal sperm ultrastructure. RESULT(S): The ICSI resulted in a fertilization rate of 63% and embryo development of good to moderate quality of 36% of the embryos. Transfer of two embryos resulted in a pregnancy and birth of a healthy child. Normal sperm centrosomes were identified retrospectively. CONCLUSION(S): Pregnancy can result in patients where the sperm are decapitated during immobilization before ICSI if normal centrosomes are present and the head and midpiece are positioned closely together.

Centrosome↗
PubMed2006

Outcome of 518 salvage oocyte-cryopreservation cycles performed as a routine procedure in an in vitro fertilization program.

OBJECTIVE: To document outcomes of oocyte cryopreservation performed as a routine procedure in an IVF program. DESIGN: Describing the rate of oocyte survival, embryo transfer (ET), implantation, and live births of IVF-intracytoplasmic sperm injection performed on thawed oocytes. SETTING: Reproductive medicine center in Italy. PATIENT(S): Women (n = 696) who failed to conceive after IVF-intracytoplasmic sperm injection with fresh oocytes. INTERVENTION(S): Surplus oocytes obtained during a failed cycle with fresh oocytes were frozen and then were thawed, micromanipulated, and transferred in a later cycle. MAIN OUTCOME MEASURE(S): Rates of oocyte survival, ETs, implantation, and live births were calculated in the entire cohort and in patients aged 38 years. RESULT(S): There were 29 pregnancies, for a total implantation rate of 6.3% (95% CI: 4.3, 9.0) per 456 ET cycles. The clinical-pregnancy rate was 19 (4.2%; 95% CI: 2.6, 6.4) of 456 ET cycles, with a take-home-baby rate of 7 (1.5%; 95% CI: 0.7, 3.0) of 456 ET cycles. CONCLUSION(S): Cryopreservation performed as a routine procedure for so-called salvaging of surplus oocytes is associated with poor implantation rates and with a probability of 1 live birth in 65 ET cycles.

Adult↗
PubMed2004

Single sperm cell isolation by laser microdissection.

In 1996, Van Oorschot and Jones firstly reported in scientific correspondence that short tandem repeat (STR) profiles could be obtained from cells left on different objects. Since then, forensic scientists have focused their efforts in isolating single cells as it can be extremely helpful in solving case works where sexual violence was concerned. Laser microdissection is a micromanipulation procedure allowing to cut off precisely the cells of interest from tissue samples or smears by a laser beam fitted with an optical microscope. We have harvested single sperm cells by laser microdissection using a Leica AS LMD (Leica Microsystems, Germany); laser setting, pulse laser intensity and laser alignment as well as recovery of the specimen have been properly fitted to the samples we were dealing with. Different tissue preservation, fixation, histological staining (Papanicolau, Nuclear Fast Red-Picroindigocarmine) methods and number of harvested cells for each sample have been evaluated as well. Finally, the genotype of sperm cells has been determined by STR typing, evaluating the sensibility of this forensic technique according to instrumental and biological above-mentioned variables.

DNA↗
PubMed2004

Fetal origin of single nucleated erythroblasts and free DNA in the peripheral blood of pregnant women.

OBJECTIVES: To investigate the feasibility of using single fetal nucleated erythroblasts (FNRBCs) and free DNA in maternal blood for non-invasive prenatal diagnosis. METHODS: Single FNRBCs were isolated from 51 of 116 samples of maternal blood analyzed by micromanipulation after density gradient centrifugation. Furthermore, the nested polymerase chain reaction (PCR) method was used to amplify the SRY gene of single FNRBCs. Primer extension pre-amplification and nested PCR were used to amplify the SRY gene of the plasma DNA extracted from 65 samples of maternal blood. RESULTS: The detection rate of single FNRBCs was 90.20% (46/51). The concordance rates between real fetal sex and sex determined by amplification of the SRY gene from single cells and from free DNA analysis were 82.61% (38/46) and 90.77% (59/65), respectively. CONCLUSIONS: Single nucleated erythroblasts and free DNA in maternal blood are of fetal origin and can be valuable fetal material sources for non-invasive prenatal diagnosis.

Adult↗
PubMed2004

Effect of polymerization conditions on the network properties of dex-HEMA microspheres and macro-hydrogels.

Dextran-hydroxy-ethyl-methacrylate (dex-HEMA) hydrogels in the form of microspheres are an attractive system for the controlled delivery of protein drugs. In this work, the microspheres were prepared by a water-in-water emulsion polymerization process. The polymerization reaction was initiated by potassium peroxodisulfate (KPS) and catalyzed by N,N,N',N'-tetramethylethylenediamine (TEMED). The effect of the initiator concentration, reaction temperature and pH on the mechanical and network properties of the microspheres were investigated. The size and size distribution of the microspheres, equilibrium water content, and methacrylate conversion were also determined. The mechanical properties of single microspheres were measured by a micromanipulation technique and the rheological characteristics of the same material in the form of macroscopic hydrogel slabs were determined by a controlled stress rheometer. The results showed that the Young's moduli of the microspheres and of macroscopic slabs measured by these two methods were in good agreement. Higher KPS initiator concentrations resulted in a more rapid polymerization with a shorter gelation and lag time, and a higher Young's modulus of the gels. An increase in temperature also resulted in a more rapid polymerization with a shorter gelation and lag time. However, the Young's modulus of the gels decreased with an increase in polymerization temperature. The pH had no significant effect on the mechanical properties of the microspheres. This study demonstrates that the network properties of dex-HEMA hydrogels can be tailored by the polymerization conditions, which opens the possibility to modulate the release rate of entrapped compounds.

Chemistry, Pharmaceutical↗
PubMed2005

The effect of the amount of binder liquid on the granulation mechanisms and structure of microcrystalline cellulose granules prepared by high shear granulation.

The structure of granules changes during the high shear granulation process. The purpose of this research was to investigate the effect of the amount of binder liquid on the structure of the granules and the structural changes which occur during the granulation process, using microcrystalline cellulose (MCC) and water as the model system. The structure is the result of the granulation mechanism; therefore, conclusions can be drawn about the latter by studying the former. X-ray microtomography and scanning electron microscopy (SEM) were applied in order to visualise the densification process of granules, which were first freeze dried in order to preserve their structure. Variations in their porosity were quantified by applying image analysis to the tomography results. In order to link the granule mechanical properties to their structural differences, a micromanipulation technique was used to measure granule resistance to deformation. MCC granules granulated with 100% (w/w) water showed increased densification with time, as expected; detailed examination showed that densification is more pronounced in the core of the granule; whereas the outer part remained more porous. Increased densification reduces deformability, so that granules become more resistant to breakage. The lower deformability of the densified granules in the final stages of granulation might result in establishment of equilibrium between attrition and growth, without substantial gross breakage. On the other hand, when more water was used (125%, w/w), densification was hardly observed; the porosity of the granule core was still high even after prolonged granulation times. This may be explained by the fact that higher water content increases the ease of deformation of granules. This increased deformability led to significant granule breakage even during the final phases of the granulation process. Therefore, for these granules a final equilibrium between breakage and coalescence might be established. This also explains why more granules produced with 125% granulation liquid were composed of fragments of irregular shape. Our results establish the link between the granulation behaviour of MCC in the latter stages and the material structure of these granules, which is determined by their liquid content. The process conditions (amount of liquid) to be chosen depend largely on the final purpose for which the granular material is produced.

Cellulose↗
PubMed2005

The relative flow of the walls of phospholipid tether bilayers.

Lipid nanotubes or "tethers" can be formed from liposomes or niosomes, pulled from the parent vesicles by micromanipulation. The tethers are cylindrical multibilayer tubes. Here, we describe the movement of these multilamellar walls, initiated by creating a surface tension gradient along the tether. The movement of lipid can give rise to a visible moving boundary. In the case of bilayer membranes, a tangential gradient in surface tension produces membrane bulk flow toward regions of higher surface tension. The flow of the bilayers comprising the tether nanotubes seems to be restricted to the inner bilayers, creating a velocity gradient in the bilayers. In this study, we discuss the implementation of tension-driven flows as a transport method in a tether-vesicle network. Interactions between fluid within the tether channels and the lipid layers are important, leading to anomalies in the transport of fluids and particles compared to bulk systems.

Cholesterol↗
PubMed2005

An extended modeling of the micropipette aspiration experiment for the characterization of the Young's modulus and Poisson's ratio of adherent thin biological samples: numerical and experimental studies.

The micropipette aspiration (MA) experiment remains a quite widely used micromanipulation technique for quantifying the elastic modulus of cells and, less frequently, of other biological samples. However, moduli estimations derived from MA experiments are only valid if the probed sample is non-adherent to the rigid substrate. This study extends this standard formulation by taking into account the influence of the sample adhesion. Using a finite element analysis of the sample aspiration into the micropipette, we derived a new expression of the aspirated length for linear elastic materials. Our results establish that (i) below a critical value, the thickness h of the probed sample must be considered to get an accurate value of its Young's modulus (ii) this critical value depends both on the Poisson's ratio and on the sample adhesivity. Additionally, we propose a novel method which allows the computation of the intrinsic Young's modulus of the adherent probed sample from its measured apparent elasticity modulus. Thanks to the set of computational graphs we derived from our theoretical analysis, we successfully validate this method by experiments performed on polyacrylamide gels. Interestingly, the original procedure we proposed allows a simultaneous quantification of the Young's modulus and of the Poisson's ratio of the adherent gel. Thus, our revisited analysis of MA experiments extends the application domain of this technique, while contributing to decrease the dispersion of elastic modulus values obtained by this method.

Acrylic Resins↗
PubMed2004

Preparation of single rice chromosome for construction of a DNA library using a laser microbeam trap.

We report the development of a laser micromanipulation system and its application in the isolation of individual rice chromosomes directly from a metaphase cell. Microdissection and flow sorting are two major methods for the isolation of single chromosome. These methods are dependent on the techniques of chromosome spread and chromosome suspension, respectively. In the development of this system, we avoided using chromosome spread and cell suspension was used instead. The cell wall of metaphase rice cell was cut by optical scissors. The released single chromosome was captured by an optical trap and transported to an area without cell debris. The isolated single chromosome was then collected and specific library was constructed by linker adaptor PCR. The average insert size of the library was about 300 bp. Two hundred inserts of chromosome 4 library were sequenced, and 96.5% were aligned to the corresponding sequences of rice chromosome 4. These results suggest the possible application of this method for the preparation of other subcellular structures and for the cloning of single macromolecule through a laser microbeam trap.

Chromosomes, Plant↗
PubMed2004

An ultra small array of electrodes for stimulating multiple inputs into a single neuron.

We have developed an ultra small, translucent array of electrodes for use in the parasaggital cerebellar slice preparation. This positionable array is capable of stimulating multiple independent bundles of parallel fibers (PFs), which synapse onto a single Purkinje neuron. On a silicon substrate, a low-stress silicon nitride film was used both as a structural layer and as electrical insulation. Evaporated gold pads and interconnects were sandwiched between two such layers. A bulk anisotropic silicon etch released the individual arrays. The electrodes are supported within a 2-microm-thick cantilever of translucent silicon nitride. In one design, eight 4-microm-wide square electrodes are arranged on 8-microm-centers. Another design, half the scale of the first, was also tested. The array was mounted on a micromanipulator and can be visualized by an upright microscope. It can then be positioned in the dendritic arbor of a Purkinje neuron while not disturbing a recording pipette at the soma. Paired-pulse facilitation experiments have confirmed that the electrodes are capable of stimulating non-overlapping bundles of PFs. This device will be useful for exploring spatiotemporal synaptic integration in single neurons. Potential applications in experiments on cerebellar LTD are also discussed.

Animals↗
PubMed2004

A MRI-compatible stereotaxic localizer box enables high-precision stereotaxic procedures in pigs.

We present a nonmagnetic Plexiglas stereotaxic localizer box that can be fitted directly to the pig skull by aluminum screws, allowing stereotaxic MRI or ventriculography and subsequent high-precision stereotaxic procedures. The localizer box was used to target the subthalamic nucleus (STN) bilaterally in five female Göttingen minipigs. Stereotaxic markers were inserted in the pig skull, the head fixated in the localizer box by aluminum screws inserted bilaterally in the zygoma bone with the hard palate locked on a horizontal palate holder. MRI was obtained on a 3T-MR-imager revealing the relation between the inserted markers and the estimated STN-position, and thus the target coordinates. After the MRI, a stereotaxic frame with attached micromanipulator was locked on to the localizer box converting it into a stereotaxic device. The stereotaxic markers were exposed and used as starting point for the stereotaxic procedure, whereby a microelectrode for electrolytic lesioning was inserted in the STN. Postmortem histological analysis revealed 70% correct STN-targeting. The average distance from the lesion center to the STN center was 1.2 mm with a S.D. of 1.1 mm. The most displaced lesion being 3.6 mm from the STN center. We conclude that the described localizer box secure firm head fixation, allowing stereotaxic MRI and subsequent conversion into a stereotaxic device for high-precision stereotaxic procedures.

Animals↗