Efficient derivation of embryonic stem cells and primordial germ cell-like cells in cattle

The induction of the germ cell lineage from pluripotent stem cells (in vitro gametogenesis) will help understand the mechanisms underlying germ cell differentiation and provide an alternative source of gametes for reproduction. This technology is especially important for cattle, which are among the most important livestock species for milk and meat production. Here, we developed a new method for robust induction of primordial germ cell-like cells (PGCLCs) from newly established bovine embryonic stem (bES) cells. First, we refined the pluripotent culture conditions for pre-implantation embryos and ES cells. Inhibition of RHO increased the number of epiblast cells in the pre-implantation embryos and dramatically improved the efficiency of ES cell establishment. We then determined suitable culture conditions for PGCLC differentiation using bES cells harboring BLIMP1-tdTomato and TFAP2C-mNeonGreen (BTTN) reporter constructs. After a 24-h culture with bone morphogenetic protein 4 (BMP4), followed by three-dimensional culture with BMP4 and a chemical agonist and WNT signaling chemical antagonist, bES cells became positive for the reporters. A set of primordial germ cells (PGC) marker genes, including PRDM1/BLIMP1, TFAP2C, SOX17, and NANOS3, were expressed in BTTN-positive cells. These bovine PGCLCs (bPGCLCs) were isolated as KIT/CD117-positive and CD44-negative cell populations. We anticipate that this method for the efficient establishment of bES cells and induction of PGCLCs will be useful for stem cell-based reproductive technologies in cattle.

Interictal High Gamma Oscillation Regularity as a Marker for Presurgical Epileptogenic Zone Localization

BACKGROUND

To ensure that epilepsy surgery is effective, accurate presurgical localization of the epileptogenic zone is essential. Our previous reports demonstrated that interictal high gamma oscillation (30-70 Hz) regularity (GOR) on intracranial electroencephalograms is related to epileptogenicity.

OBJECTIVE

To examine whether preoperative GOR analysis with interictal high-density electroencephalography (HD-EEG) improves the accuracy of epileptogenic focus localization and enhances postoperative seizure control.

METHODS

We calculated GOR from 20 seconds of HD-EEG data for 21 patients with refractory focal epilepsy (4 with nonlesional temporal lobe epilepsy) scheduled for epilepsy surgery. Low-resolution brain electromagnetic tomography was used to analyze the high GOR source. To validate our findings, we made comparisons with other conventional localization methods and postoperative seizure outcomes.

RESULTS

In all patients, the areas of interictal high GOR were identified and resected. All patients were seizure-free after the operation. The concordance between the results of interictal high GOR on HD-EEG and those of source estimation of interictal discharge was fully overlapping in 10 cases, partially overlapping in 8 cases, and discordant in 3 cases. The concordance between the results of interictal high GOR on HD-EEG and those of interictal 123 I-iomazenil single-photon emission computed tomography was fully overlapping in 8 cases, partially overlapping in 11 cases, and discordant in 2 cases. In 4 patients with nonlesional temporal lobe epilepsy, the interictal high GOR on HD-EEG was useful in confirming the epileptogenic zone.

CONCLUSION

The interictal high GOR on HD-EEG is an excellent marker for presurgical epileptogenic zone localization.

Prolonging hypothermic storage (4 C) of bovine embryos with fish antifreeze protein

Embryos obtained via superovulation are necessary for mammalian artificial reproduction, and viability is a key determinant of success. Nonfreezing storage at 4 C is possible, but currently used storage solutions can maintain embryo viability for only 24-48 h. Here we found that 10 mg/ml antifreeze protein (AFP) dissolved in culture medium 199 with 20% (v/v) fetal bovine serum and 25 mM HEPES could keep bovine embryos alive for 10 days at 4 C. We used a recombinant AFP isolated from the notched-fin eelpout (Zoarces elongatus Kner). Photomicroscopy indicated that the AFP-embryo interaction was enhanced at 37 C. Embryos pre-warmed with the AFP solution at 37 C for 60 min maintained high viability, whereas those that were not pre-warmed could live no longer than 7 days. Thus, short-term storage of bovine embryos was achieved by a combination of AFP-containing medium and controlled pre-warming.

Ictal near-infrared spectroscopy and electrocorticography study of supplementary motor area seizures

The seizure onset zone (SOZ) and propagation pathways in supplementary motor area (SMA) seizures are difficult to identify because of the short duration and swift propagations of this seizure type. Herein, we studied ictal cerebral blood flow changes, seizure electrical activities, and clinical signs employing simultaneous near-infrared spectroscopy (NIRS) and electrocorticography (ECoG) recordings in a brain tumor patient with SMA seizures. Increased cerebral blood flow was observed from the SOZ in the ipsilateral SMA and spread to the ipsilateral premotor cortex, ipsilateral sensorimotor cortex, and also the contralateral hemisphere. These propagation patterns were concordant with ictal ECoG seizure activities and clinical signs. Removal of the SOZ and surrounding areas, where the higher blood flow and higher frequency oscillations had been identified, achieved a good outcome for this patient. Our ictal NIRS-ECoG technique is robust and useful for detecting the SOZ and seizure propagations.

156 THE USE OF THE DG29™ ENZYME-LINKED IMMUNOSORBENT ASSAY KIT TO PREDICT PREGNANCY PRIOR TO EMBRYO TRANSFER IN LACTATING HOLSTEIN COWS

Evaluation of postpartum fertility in cows is important for the efficient management of reproduction. DG29™ enzyme-linked immunosorbent assay (ELISA) kit (Conception, Animal Reproduction Technologies, Canada) measures the level of pregnancy–related glycoproteins in blood that are linked to pregnancy in the bovine species. The proteins are known to persist in the postpartum period. Here, we investigated whether the postpartum fertility in Holstein dairy cows can be evaluated through the use of the DG29 kit. We confirmed that genital organs of lactating Holstein cows (n = 119, from Days 56 to 688 postpartum) were normal by a 5.0/7.5-MHz linear array transducer (Tringa, Pie Medical Equipment B.V., Maastricht, The Netherlands), then a progesterone releasing intravaginal device (PRID; CEVA Sante Animale, Libourne, France) was inserted (Day 0) and maintained for 9 days. On Day 7, PGF2α was administered (2 mL Dalmazine, Kyoritsu Seiyaku, Tokyo, Japan). Blood samples were collected from the tail vein or artery into vacuum tubes at the time of PRID insertion. Serum was separated and stored at –30°C until the ELISA was performed. Oestrus (Day 0) was detected by visual observation. Fresh embryos recovered from Japanese Black cows were transferred to 119 recipient cows in various parities (primiparous = 70, biparous = 27, and multiparous = 22) on Days 6 to 8 of oestrous cycle. Pregnancy was diagnosed between Days 40 to 60 by transrectal ultrasonography. The statistical significance of any differences between various parities was assessed by chi-squared and Student’s t-tests. The pregnancy rate was higher for primiparous cows than for biparous and multiparous cows (64.3, 55.6, and 54.5%, respectively), while concentrations of the pregnancy-related glycoproteins in primiparous cows (135.0 ± 29.8 pg mL–1) were significantly lower than those of biparous (389.4 ± 175.9 pg mL–1) and multiparous cows (399.2 ± 203.1 pg mL–1, mean ± SEM; P < 0.05). In primiparous and multiparous cows, the concentrations of pregnancy-related glycoproteins were significantly lower in pregnant cows compared with nonpregnant cows (primiparous: 81.1 ± 29.9 v. 232.6 ± 59.8 pg mL–1; P < 0.05; multiparous: 20.8 ± 16.2 v. 853.4 ± 411.5 pg mL–1; P < 0.05). However, there was no significant difference between pregnant and nonpregnant biparous cows. In conclusion, the DG29 kit may be useful for the prediction of postpartum fertility in lactating Holstein cows. Further studies are needed to test the validity of this observation by using a greater number of various parties’ cows.

109 RELATIONSHIP BETWEEN ULTRASONIC MORPHOLOGY OF CORPUS LUTEUM IN HOLSTEIN HEIFERS AND PREGNANCY RATE AFTER EMBRYO TRANSFER

Recipient animals for bovine embryo transfer (ET) are routinely selected according to the morphology of the corpus luteum (CL) estimated by rectal palpation. However, rectal palpation is not a precise method of diagnosing the functional status of a CL. Ovarian ultrasonography (US) may be used to improve such diagnoses. The aim of this study was to evaluate the relationship between ultrasonographic images of CL and pregnancy rates after ET in Holstein heifers to determine whether US can be used to select recipients for ET. Recipient heifers (n = 285) were selected by detection of natural oestrus or following oestrus synchronization using a progesterone-releasing intravaginal device (PRID; ASKA Pharmaceutical, Tokyo, Japan). Transrectal US was performed immediately before ET, on Days 6 to 8 of the oestrous cycle (oestrus = Day 0), using a B-mode scanner (HS1500V; Honda Electronics Co. LTD, Aichi, Japan) equipped with a 7.5-MHz linear-array transducer designed for intrarectal placement. A cross-sectional image of the maximal area of the CL and luteal cavity was obtained. The areas of the CL and luteal cavity were each calculated using the formula for the area of an ellipse (height/2 × width/2 × π). (1) Ultrasonic morphology of CL was classified into 3 types: without cavity (n = 128), with cavity (n = 145) and with blood clot (n = 12). (2) The luteal cavity was categorized into 3 groups: small (<100 mm2, n = 93), medium (100 ≤ x < 200 mm2, n = 32) and large (≥200 mm2, n = 20). (3) Luteinized tissue area (total area of CL minus the area of the luteal cavity) was categorized into 3 groups: small (<250 mm2, n = 61), medium (250 ≤ x < 350 mm2, n = 128) and large (≥350 mm2, n = 84). In vivo–produced embryos were transferred nonsurgically into the uterine horn ipsilateral to the CL. Pregnancy was determined by transrectal US on Days 30 to 40 of gestation. The pregnancy rates of each experimental group were analysed by logistic regression. In this study, the pregnancy rate did not differ significantly in each experimental group: (1) without cavity: 77.3% (99/128), with cavity: 75.2% (109/145) and blood clot: 75.0% (9/12); (2) small cavity: 73.1% (68/93), medium: 75.0% (24/32) and large: 85.0% (17/20). The mean area of the cavity was 100.8 ± 110.3 mm2 (mean ± standard deviation) and recipients with 0 to 539.7 mm2 sized cavities had successful pregnancies (observational range was 0 to 539.7 mm2). (3) The pregnancy rates of recipients that had small, medium and large luteinized tissue were 77.0% (47/61), 75.0% (96/128) and 77.4% (65/84), respectively. The mean area of luteinized tissue was 318.9 ± 90.3 mm2 and 155.0 to 620.0 mm2 sized luteinized tissue had pregnancy success (observational range was 132.8 to 620.0 mm2). In conclusion, the results from this study indicate that the presence of a luteal cavity or blood clot has no detrimental effect on pregnancy success after ET in Holstein heifers. Furthermore, no relationship was found between luteinized tissue area at the time of ET and pregnancy rate.

75 COMPARISON OF THE DG29TM ENZYME-LINKED IMMUNOSORBENT ASSAY KIT COMPARED WITH TRANSRECTAL ULTRASONOGRAPHY FOR EARLY PREGNANCY DIAGNOSIS FOLLOWING TRANSFER OF JAPANESE BLACK CATTLE EMBRYOS

In commercial embryo transfer industry, accurate early detection of pregnant and nonpregnant cows plays a key role in achieving an optimum calving-to-conception interval. The DG29TM enzyme-linked immunosorbent assay (ELISA) kit (Conception, Animal Reproduction Technologies, Beaumont, Canada) measures the level of pregnancy-related glycoproteins in blood that are linked to pregnancy. Here, we compared the DG29 kit with transrectal ultrasonography (TU) to evaluate the possibility of the clinical application of the ELISA kit for early pregnancy diagnosis. Embryos recovered from superovulated Japanese Black cows were transferred to 110 recipient Holstein heifers on Day 6 to 8 of the oestrous cycle (oestrus = Day 0). Pregnancy was diagnosed between Day 29 and Day 40 by TU with a 5.0/7.5-MHz linear array transducer (Tringa, Pie Medical Equipment B.V., Maastricht, the Netherlands). Blood samples were collected from the tail vein or artery into vacuum serum tubes after TU and serum was separated and stored at –30°C until the ELISA was performed. The ELISA results were interpreted as positive (pregnant, >1000 pg mL–1) or negative (nonpregnant, <300 pg mL–1). Ninety-nine of the 110 heifers were judged as pregnant or nonpregnant by TU. Seventy-six of the 99 heifers were judged as pregnant, in which fetuses were visualised clearly in the uterine horn. The following measures, sensitivity, specificity, predictive value and accuracy of pregnancy outcomes based on the ELISA results, were assessed by comparing with those based on the definite TU results. The values for sensitivity and specificity were 100% (76/76) and 91.3% (21/23), the positive and negative predictive value were 97.4% (76/78) and 100% (21/21), respectively and accuracy was 98.0% (97/99). On the other hand, chorioallantoic fluids in 11 of the 110 heifers were detected by TU around Day 30 of gestation, but fetuses were not identified or were unclearly visualised, which suggests that the embryos died during the peri-implantation period after transfer. Ten of the 11 heifers were classified as pregnant by the ELISA, but only 3 heifers were identified as pregnant with reexamination by later TU, which indicates that the pregnancy-related glycoproteins residue from embryo mortality was detected by the DG29 kit. However, the negative predictive value of the DG29 kit was 100% in this study. In conclusion, except for early embryonic death, the DG29 kit was highly accurate and suitable for clinical application in early pregnancy determination following transfer of Japanese Black cattle embryos.

EEG Dipole Characteristics in Panayiotopoulos Syndrome

PURPOSE

Panayiotopoulos syndrome (PS) is a type of benign childhood partial epilepsy that is frequently associated with abundant multifocal spikes other than main occipital spikes on the EEG. In this study, we investigated the characteristic features of dipoles in PS.

METHODS

We performed dipole analysis of the interictal occipital spike discharges seen in 10 children with PS (group A) and in 10 children with other types of symptomatic localization-related epilepsy (group B). We analyzed the dipoles of the averaged spike in each patient.

RESULTS

In group A, the averaged occipital spikes in each patient showed dense dipole locations in the mesial occipital area; in group B, widely scattered dipole locations were observed. In Group A, the geometric centers of the dipoles at each time point (such as at the main negative peak and before or after the main peak) were estimated in the neighboring locations. In contrast, they tended to be scattered in group B.

CONCLUSIONS

Our study reveals that PS has high dipole stability, similar to that of rolandic epilepsy. From the electroencephalographic view, this seems to indicate a close link between these two syndromes.

Dipole analysis in panayiotopoulos syndrome

Panayiotopoulos syndrome (PS) is a type of benign childhood partial epilepsy, which has a good prognosis despite the fact that it is frequently associated with abundant multifocal spikes on the electroencephalography (EEG). We investigated whether stable dipoles, as seen in rolandic epilepsy, were also present in PS. We performed dipole analysis of the interictal spike discharges seen in the interictal EEGs of eight children with PS. We chose more than 10 spikes for each kind of spike, and investigated whether or not more than three of these spikes showed consistently stable dipole locations. (1) We observed 15 different kinds of spikes in various regions in the EEGs of the eight children. (2) Twelve of the 15 kinds of spikes had dipoles with a high goodness of fit. Furthermore, 14 of the 15 spikes had stable dipoles with similar locations for more than three individual spikes. (3) Fourteen of the 15 spikes, including frontal spikes, showed dense dipole locations in the mesial occipital area. Thirteen of these 14 spikes also showed other dipole locations in the rolandic area and/or the vertex (Cz). Our study revealed that the various types of spikes observed in PS have similar and stable dipole locations. The dipoles showing high stability, were located in the mesial occipital area, and were accompanied by dipoles located in the rolandic area. The stability and location of these dipoles indicate that there may be a pathogenetic link between PS and rolandic epilepsy.

Characteristics of dipoles in clustered individual spikes and averaged spikes

The aim of this study is to analyze the characteristics of dipoles in clustered individual spikes and averaged spikes, we compared electroencephalography (EEG) dipole localizations from patients with intractable extratemporal lobe epilepsy (IETLE) and from patients with benign epilepsy with centrotemporal spikes (BECTS). We studied 10 patients; five with IETLE who underwent epilepsy surgery after subdural EEG and five with BECTS. We recorded 19-channel digital scalp EEGs and used clustering analysis for individual spikes to characterize interictal spikes. We selected and averaged one representative spike group at the maximum negative peak electrode. We used a single dipole method with three-shell spherical head model. We compared dipole localizations of both averaged and individual spikes.IETLE data had more identifiable spike clusters and fewer spikes in each cluster than BECTS (P<0.05). Dipole sources with goodness-of-fit >or=95% in averaged spikes were less frequent in IETLE than in BECTS (P<0.05). For IETLE, averaged spikes showed no dipoles (two patients), while individual spikes gave dipole sources reliably in the epileptic region. For BECTS, individual and averaged spike sources were clustered. More than 80% of dipoles in averaged spikes were stable, in close proximity, for prolonged periods in BECTS. More spike groups after clustering and fewer acceptable dipoles from averaged spikes in IETLE reflect variable spike activity over extensive epileptic regions. Fewer spike groups producing more acceptable dipoles in BECTS correlate with stable spike sources within the isolated epileptic central region. Characteristics of clustered interictal spikes need careful examination before the use of dipole analysis of averaged spikes for epilepsy evaluation.

Computerized brain-surface voltage topographic mapping for localization of intracranial spikes from electrocorticography. Technical note

The purpose of this paper is to describe the use of computerized brain-surface voltage topographic mapping to localize and identify epileptic discharges recorded on electrocorticographic (ECoG) studies in which a subdural grid was used during intracranial video electroencephalographic (IVEEG) monitoring. The authors studied 12 children who underwent surgery for intractable extrahippocampal epilepsy. Cortical surfaces and subdural grid electrodes were photographed during the initial surgery to create an electrode map that could be superimposed onto a picture of the brain surface. Spikes were selected from ictal discharges recorded at the beginning of clinically confirmed seizures and from interictal discharges seen on ECoG studies during IVEEG recording. A computer program was used to calculate the sequential amplitude of the spikes by using squared interpolation, and they were then superimposed onto the electrode map. Interictal discharges and high-amplitude spike complexes at seizure onset were plotted on the map. This mapping procedure depicted the ictal zone in nine patients and the interictal zone in 12, and proved to be an accurate and useful source of information for planning corrective surgery.

Systematic approach to dipole localization of interictal EEG spikes in children with extratemporal lobe epilepsies

OBJECTIVES

To assess the reliability of dipole localization based on residual variances (RV), using equivalent current dipole analysis of interictal EEG spikes in children with extratemporal lobe epilepsy.

METHODS

Four pediatric patients with extratemporal lobe epilepsy were studied. Digital EEG was recorded from 19 scalp electrodes. Computer programs for spike detection and clustering analysis were used to select spikes. Dipoles were calculated 5 times for each spike using different initial guesses by the moving dipole model. Standard deviation (SD) of the dipole positions was calculated at each time point in the 5 trials.

RESULTS

We analyzed the dipoles at 1097 time points from 4 patients. Among 106 time points with RV < 2%, the SD was < 1 mm in 78 (74%), while in those with SD > 1 mm the dipole positions varied between 2.8 and 52.6 mm. Of dipoles with RV < 1%, 26 of 27 (96%) had an SD < 1 mm; the one dipole with SD > 1 mm varied within 2.5 mm. The dipole localizations with RV < 2% corresponded to the epileptogenic zones identified on intracranial invasive video EEG and intraoperative ECoG.

CONCLUSIONS

The systematic approach of equivalent current dipole analysis using spike detection, clustering analysis, and an RV < 2% as a standard is useful for identifying extratemporal epileptic regions.

Utility of digital camera-derived intraoperative images in the planning of epilepsy surgery for children

OBJECTIVE

This study was undertaken to assess the utility of digital camera-derived intraoperative images in the planning of neurosurgery for children with epilepsy.

METHODS

A hand-held digital camera was used to capture the exposed surgical field at the time of craniotomy for 11 children with medically intractable seizure disorders. Intraoperative somatosensory evoked potential recordings of phase reversals and direct cortical stimulation were used to map areas of eloquent brain tissue. Digital camera images were obtained to mark regions of functional brain tissue with respect to cortical surface landmarks and subdural grid placement. The digital camera images were then immediately downloaded, in the operating room, to a laptop computer, which was placed next to the electroencephalographic recording device. Using computer software, the epileptologist highlighted the primary and secondary zones of epileptogenesis, as well as the functional brain areas identified during the monitoring period, on the digital camera images on the computer screen. A neurosurgical map was thus created to aid the neurosurgeon and the epileptologist with the proposed cortical resections and multiple subpial transections.

RESULTS

With the images obtained using the digital camera, the epilepsy team was able to observe the contacts of the grid electrodes with the brain during the procedure. Color printouts of the images served as references during the period of invasive monitoring. Zones of primary and secondary epileptogenesis, as well as areas of functional brain tissue, were identified and plotted on the digital camera images. Other benefits of the digital camera-derived images included the ability to accurately reposition the grids or letters marking eloquent brain tissue if they were inadvertently shifted during the procedure, the ease with which the images could be obtained and manipulated, the ability to assess postresection epileptiform activity of the surrounding brain tissue with images obtained while an electrocorticographic array was in place, the ability to provide the entire epilepsy team with updated information on the neurosurgical field while minimizing movement in the operating room, and facilitation, with neurosurgical maps, of discussions with the patients and their families concerning proposed cortical resections.

CONCLUSION

Digital camera images have become essential components for the planning of cortical resections for children with intractable epilepsy at our institution. We envision widespread application of this technology to other neurosurgical fields.

Interhemispheric interactions analyzed by coherence during flexor spasms

OBJECTIVE

We used coherence analysis to test for leading discharges on an ipsilateral right mesial temporal lesion in a 5 year old boy with flexor spasms.

METHOD

Digital EEG analysis with video-EEG telemetry was performed preparatory to epilepsy surgery.

RESULTS

Study of 10 spasms with head drop and subsequent flexion of both arms demonstrated an interhemispheric time lag with secondary bilateral synchrony, with a mean difference of 17 ms. The right hemisphere led. After a lesionectomy with resection of epileptic regions (performed with electrocorticographical guidance), the patient has been seizure-free for 4 years. Pathology confirmed a low-grade mixed glioma and cortical dysgenesis.

CONCLUSION

The coherence analysis demonstrated a pathway of secondary generalization, confirming that the lesional side was leading during ictal generalized discharges in flexor spasms.

[A case of hereditary motor and sensory neuropathy with pyramidal tract sign, optic nerve atrophy and mental retardation]

The patient was a 61-year-old man who suffered from gait disturbance since childhood. He also had mental retardation. Gait disturbance was slowly progressive. His mother, sister, brother and son of his sister suffered from gait disturbance. On neurological examination, he showed mental retardation, optic nerve atrophy and neural deafness. He also showed severe muscle atrophy and weakness of bilateral lower limbs associated with pes cavus. Muscle tonus of lower limbs and patellar tendon reflex were increased bilaterally. Achilles tendon reflex was absent. Babinski and Chaddock signs were positive. Superficial and deep sensations were almost normal. There were no cerebellar signs. Blood chemistry was normal. On nerve conduction studies, motor nerve conduction velocity of the upper limbs was normal and that of the posterior tibial nerve was decreased; right 36.0m/sec, left 29.7m/sec. Sensory nerve conduction velocity of the median nerve was slightly decreased; right 36.5m/sec, left 45.2m/sec and sural nerve did not respond to electric stimuli. On sural nerve biopsy, the density of myelinated fibers was severely decreased. Onion bulb formation was not observed. We classified this case as hereditary motor and sensory neuropathy (HMSN) type II based on nerve conduction studies and findings from sural nerve biopsy. HMSN with pyramidal tract sign has been classified as type V and HMSN with optic nerve atrophy as type VI. This case had characteristic symptoms as type V and VI. Histopathological findings of HMSN type V and VI have not been established yet. This case might provide an important clue for classification of HMSN.