85 The effects of heat exposure on the growth and developmental competence of oocytes derived from early antral follicles in dairy cows

Summer heat stress in dairy cows impairs the developmental competence of oocytes from antral follicles (2–8mm) which are used in conventional IVM and IVF systems. Moreover, summer heat stress is considered to impair the oocyte competence derived from smaller follicles; therefore, the impairment of oocyte competence possibly continues into the cooler autumn season. To investigate the thermosensitivity of early antral follicles (<1mm), we evaluated the effects of heat exposure on the growth and developmental competence of oocytes using invitro culture of oocyte–cumulus-granulosa complexes (OCGCs) derived from early antral follicles. OCGCs (n=315) were collected from early antral follicles (0.5–1mm) and cultured for 12 days. OCGCs in the heat shock group were cultured using a temperature cycle of 38.5°C for 5h, 39.5°C for 5h, 40.5°C for 5h, and 39.5°C for 9h, whereas those in the control group were cultured at a constant temperature of 38.5°C for 24h. The diameters of oocytes were measured before culture. Half of the culture medium was replaced every 4 days. Oestradiol-17β (E2) and progesterone (P4) production during the first, second, and third 4-day periods were measured by enzyme immunoassay; the viability of OCGCs was evaluated based on their morphology. Oocytes that survived after 12 days of culture (n=191) were subjected to IVM (38.5°C, 22h); their diameter and nuclear status were evaluated. Some oocytes (n=71) were subjected to IVF (38.5°C, 18h) and embryo culture (39.0°C, 150h). Cleavage and blastocyst rates were evaluated at 48h and 168h after IVF. Effects of treatment groups and culture periods on E2 and P4 production and diameters of oocytes were evaluated by two-way ANOVA followed by Tukey-Kramer or Student’s t-test. The viability of OCGCs, nuclear maturation, cleavage and blastocyst rates between two groups were compared by the chi-squared or Fisher’s exact test. E2 and P4 production and the viability of OCGCs were not different between the 2 groups. Although mean oocyte diameters before culture did not differ between the 2 groups, the mean diameters after IVM were significantly smaller in the heat shock group (108.0µm, n=56) than in the control group (111.7µm, n=61; P<0.05). The nuclear maturation rate in the heat shock group (36.4%, n=55) was significantly lower than in the control group (60.3%, n=58; P<0.05). Cleavage rates were similar between the control (54.5%, n=33) and heat shock groups (45.7%, n=35). However, no oocytes developed to blastocysts in the heat shock group (0%, n=35), whereas 30.3% (n=33) oocytes developed to blastocysts (cell number±s.d.; 92.4±28.4) in the control group (P<0.05). These findings suggest that summer heat stress in dairy cows impairs the growth, nuclear maturation, and developmental competence of oocytes derived from early antral follicles. This experimental model could be used to explore the mechanisms by which heat stress subsequently impairs oocyte competence during the cooler autumn season.

P1745Clinical characteristics and long-term outcome in patients with helicopter-transported acute coronary syndrome after primary percutaneous coronary intervention

Background

Reducing delay to percutaneous coronary intervention improves functional outcome and reduces long-term mortality. Transportation by helicopter is often quicker than ground transport and thus may improve overall prognosis through reduced ischemic injury and infarction size. Our hospital is located on the medically-depopulated peninsula surrounded by mountain. The journey from the southern tip of the peninsula to the critical care medical center of our hospital take 1.5 hour by a ground ambulance but only 15 minutes by helicopter.

We compared the clinical characteristics and long-term mortality between air and ground transport of ACS patients for primary PCI.

Methods

We conducted an observational cohort study evaluating 2324 patients (mean age 68.5±12.0, male 75.2%) with ACS underwent primary PCI between April 2004 and December 2017 at our hospital.

We divided into three groups according to transportation system type (air, ground, walk-in).

The primary outcome was defined as all-cause death during the long-term follow-up.

Results

Among the entire cohort, 577 patients (24.8%) were transported by air. 1326 (57.1%) patients by ambulance, 421 (18.1%) patients by walk. Baseline characteristics were comparable, but patients by air had a higher prevalence of ST-elevation myocardial infarction.

The rate of long-term mortality was comparable during the median follow up of 6 years (air, 21.1% vs. ground, 21.4% vs. walk-in, 21.1%, respectively, log-rank p=0.72). Multivariate Cox regression analysis showed no significant association between air transportation and long-term mortality (Adjusted HR [vs ground] 1.05, 95% CI 0.60–1.78, p=0.85 and [vs walk-in] 0.94, 95% CI 0.62–1.43, respectively, p=0.77).

Kaplan-Meier curve

Conclusions

The rate of long-term mortality in patients with ACS transported by air was comparable with those transported by ground.

Astaxanthin improves the developmental competence of in vitro-grown oocytes and modifies the steroidogenesis of granulosa cells derived from bovine early antral follicles

In this study we investigated the effect of astaxanthin (Ax), which exhibits strong antioxidant activity, during invitro growth (IVG) on the developmental competence of oocytes and steroidogenesis of granulosa cells derived from early antral follicles. Bovine oocyte–cumulus–granulosa complexes collected from early antral follicles were cultured for 12 days in the presence or absence (control) of 500µM Ax. The viability of oocytes and antrum formation in the granulosa cell layer during IVG culture were greater in the presence than absence of Ax (P<0.05). Regardless of Ax treatment, 17β-oestradiol production increased during IVG culture; however, progesterone production was significantly lower in the presence than absence of Ax (P<0.05). Reactive oxygen species levels were lower in Ax-treated oocytes than in controls after IVG (P<0.05). Although nuclear maturation and cleavage rates did not differ between the Ax-treated and control groups, Ax treatment led to weaker cathepsin B activity in oocytes and better blastocyst rates than in controls (P<0.05). Accordingly, Ax treatment during IVG increased the total number of cells in blastocysts (P<0.05). These results indicate that Ax supplementation of IVG medium improves the quality of bovine oocytes due to its antioxidative effects on growing oocytes and its suppression of the luteinisation of granulosa cells.

120 Effects of antral follicle count in ovaries on follicular development and endocrine dynamics of follicle-stimulating hormone and steroid hormones in cattle

The antral follicle count (AFC) in mammalian ovaries positively correlates with female fertility. We have reported previously that cumulus-oocyte complexes derived from high-AFC ovaries produce more oestradiol-17β (E2) and have higher developmental competence than those from low-AFC ovaries in in vitro growth (Sakaguchi et al. WCRB2017, Okinawa, Japan; 1-15). We also indicated that follicular growth was different between high- and low-AFC cows, and that follicular deviation occurred earlier in high-AFC cows (Nagai et al. 2015 Anim. Reprod. Sci. 163, 172-178). To clarify the causes of the higher E2 production and earlier follicular deviation in high-AFC cows, we investigated circulating steroid hormones and FSH during the oestrous cycle, as well as steroidogenesis in follicles at different phases of the oestrous cycle. Four high-AFC cows (>40 follicles) and 3 low-AFC cows (<20 follicles) based on the peak AFC were used. We ablated their follicles 8 days after oestrus and administered prostaglandin F2α on Day 12. After 40h of prostaglandin F2α injection, follicular fluid of a dominant follicle (preovulatory phase) was collected and subordinate follicles were ablated. Gonadotropin-releasing hormone was then injected to induce LH surge. Seven days after gonadotropin-releasing hormone, follicular fluids were collected from dominant follicles (luteal phase) and all follicles were ablated. Four days later, follicular fluids were again collected from the largest follicles (selection phase). Steroid hormones in follicular fluids were measured by enzyme immunoassay. Throughout the study, we daily examined ovaries by ultrasonography and collected blood for hormone measurements. We analysed data using two-way ANOVA followed by Tukey-Kramer or Student’s t test. The number of small follicles (<4mm) was greater in high-AFC than low-AFC groups (low v. high=7.6v. 46.9; P<0.05), whereas that of large follicles (>8mm) was similar between groups (0.8v. 0.8) at any time. Although the number of medium-sized follicles (4-8mm) was not affected in the low-AFC group (4.2-6.7) after follicle ablation, the number increased from 1 to 4 days (10.5 to 17.8) then decreased 6 days after follicle ablation (11.5) in the high-AFC group, which means that degradation of follicles occurs at selection phase in high-AFC cows. Peripheral FSH concentration was higher (low v. high: 4.7v. 2.1 ng/mL), but E2 concentration was lower in the low-AFC (2.4 pg/mL) than high-AFC group (3.3 pg/mL) during the selection phase (P<0.05). Although follicular diameter was similar in both groups at any phase, E2 (low v. high=333.8v. 1127.4 ng/mL; P<0.05) and testosterone (low v. high=16.7v. 35.0 ng/mL; P=0.07), but not progesterone, concentrations were higher in the high-AFC than low-AFC group in the preovulatory phase. These findings suggest that a lower response to FSH causes low E2 production in the low-AFC group, resulting in high FSH concentration and a consistent development of medium-sized follicles. Conversely, higher E2 concentration suppresses FSH secretion, resulting in obvious degradation of follicles in the high-AFC group at the selection phase.

Collaboration of local government and experts responding to increase in environmental radiation level due to the nuclear disaster: focusing on their activities and latest radiological discussion

Activities were introduced in Kashiwa city in the Tokyo metropolitan area to correspond to the elevated environmental radiation level after the disaster of the Fukushima Daiichi nuclear power plant. These were based on a strong cooperation between local governments and experts. Ambient dose rate and radioactivity of foodstuff produced inside of the city have been monitored. Representative ambient dose rates around living environments have almost already become their original levels of the pre-accident because of the decontamination activity, natural washout and effective half-lives of radioactivity. The internal annual dose due to radioactive cesium under the policy of 'Local Production for Local Consumption' is estimated as extremely low comparing the variation range due to natural radioactivity. Systematic survey around a retention basin has been started. All of these latest monitoring data would be one of the core information for the policy making as well as a cost-benefit discussion and risk communication.

Transcriptional regulation of glutamic acid decarboxylase in the male mouse amygdala by dietary phyto-oestrogens

Phyto-oestrogens are biologically active components of many human and laboratory animal diets. In the present study, we investigated, in adult male mice with C57BL/6 genetic background, the effects of a reduced phyto-oestrogens intake on anxiety-related behaviour and associated gene expression in the amygdala. After 6 weeks on a low-phyto-oestrogen diet (< 20 μg/g cumulative phyto-oestrogen content), animals showed reduced centre exploration in an open-field task compared to their littermates on a soybean-based standard diet (300 μg/g). Freezing behaviour in an auditory fear memory task, in contrast, was not affected. We hypothesised that this mildly increased anxiety may involve changes in the function of GABAergic local circuit neurones in the amygdala. Using GAD67(+/GFP) mice, we could demonstrate reduced transcription of the GAD67 gene in the lateral and basolateral amygdala under the low-phyto-oestrogen diet. Analysis of mRNA levels in microdissected samples confirmed this regulation and demonstrated concomitant changes in expression of the second glutamic acid decarboxylase (GAD) isoform, GAD65, as well as the anxiolytic neuropeptide Y. These molecular and behavioural alterations occurred without apparent changes in circulating oestrogens or testosterone levels. Our data suggest that expression regulation of interneurone-specific gene products in the amygdala may provide a mechanism for the control of anxiety-related behaviour through dietary phyto-oestrogens.

Investigation of exercise intensity during a freestyle wrestling match

AIM

This study investigated changes in exercise intensity during a freestyle wrestling match.

METHODS

Wrestling matches that consisted of three periods of 2 min were performed by nine elite collegiate male wrestlers. Exercise intensity was measured using heart rate (HR), blood lactate concentration ([BLa-]), and rating of perceived exertion (RPE). HR was continuously recorded during the match, and mean HR during each period was obtained. [BLa-] and RPE according to the 6-20-point Borg Perceived Exertion Scale were measured immediately after each period.

RESULTS

HR during the wrestling match increased as a whole, but a continuous decrease in HR was observed during the first half of the second and third periods. This was likely caused by a cautious strategy involving reduced aggressive actions. HR significantly increased (P<0.05) from the first period (81 ± 6% of maximal HR [HRmax]) to the second period (88 ± 5% of HR(max)), and from the second to the third periods (92 ± 5% of HR(max)). [BLa-] significantly increased (P<0.05) from the first period (7.6 ± 2.0 mmol.L⁻¹) to the second period (10.4 ± 4.2 mmol.L⁻¹), but not from the second to the third periods (11.5 ± 3.1 mmol.L⁻¹). RPE significantly increased across the three periods (first, 13 ± 1; second, 15 ± 2; and third periods, 17 ± 2, P<0.05).

CONCLUSION

Our results on changes in exercise intensity during each period and between periods would be helpful for making strategic decisions during wrestling matches and for planning daily training.

Selective loss of parvalbumin-positive GABAergic interneurons in the cerebral cortex of maternally stressed Gad1-heterozygous mouse offspring

Exposure to maternal stress (MS) and mutations in GAD1, which encodes the γ-aminobutyric acid (GABA) synthesizing enzyme glutamate decarboxylase (GAD) 67, are both risk factors for psychiatric disorders. However, the relationship between these risk factors remains unclear. Interestingly, the critical period of MS for psychiatric disorders in offspring corresponds to the period of GABAergic neuron neurogenesis and migration in the fetal brain, that is, in the late stage of gestation. Indeed, decrement of parvalbumin (PV)-positive GABAergic interneurons in the medial prefrontal cortex (mPFC) and hippocampus (HIP) has often been observed in schizophrenia patients. In the present study, we used GAD67-green fluorescent protein (GFP) knock-in mice (that is, mice in which the Gad1 gene is heterozygously deleted; GAD67(+/GFP)) that underwent prenatal stress from embryonic day 15.0 to 17.5 and monitored PV-positive GABAergic neurons to address the interaction between Gad1 disruption and stress. Administration of 5-bromo-2-deoxyuridine revealed that neurogenesis of GFP-positive GABAergic neurons, but not cortical plate cells, was significantly diminished in fetal brains during MS. Differential expression of glucocorticoid receptors by different progenitor cell types may underlie this differential outcome. Postnatally, the density of PV-positive, but not PV-negative, GABAergic neurons was significantly decreased in the mPFC, HIP and somatosensory cortex but not in the motor cortex of GAD67(+/GFP) mice. By contrast, these findings were not observed in wild-type (GAD67(+/+)) offspring. These results suggest that prenatal stress, in addition to heterozygous deletion of Gad1, could specifically disturb the proliferation of neurons destined to be PV-positive GABAergic interneurons.

Importance of checking prehospital neurological findings to reveal incidence of spinal cord concussion

OBJECTIVE

To clarify the incidence and characteristics of spinal cord concussion in an urban city in Japan.

METHODS

The current retrospective study was conducted by reviewing the medical records of patients with spinal cord injuries admitted between January 2007 and December 2010. The subjects were divided into two groups: a spinal cord concussion group and a spinal cord injury group.

RESULTS

There were 36 patients with spinal cord injuries admitted during this period. Among them, there were 8 patients with spinal cord concussions. No significant differences were apparent between the two groups with regard to sex, mechanism of injury, Glasgow Coma Scale, incidence of shock, inhospital Frankel classification, level of spinal cord injury, frequency of vertebral dislocation/fracture, surgery and the survival rate. However, the mean age in the spinal cord concussion group was lower than that in the spinal cord injury group. The systolic blood pressure, the heart rate and the diameter of minimum spinal canal in the concussion group were all higher than those in the spinal cord injury group. Half of the subjects in the spinal cord concussion group demonstrated immediate neurological improvement between prehospital and inhospital findings, however none of the subjects in the spinal cord injury group demonstrated such improvement. This difference was statistically significant.

CONCLUSION

Spinal cord concussion is not rare in urban Japan. Checking neurological findings at the scene leads to the revelation of the true high incidence of spinal cord concussion among spinal cord injuries.

Complex receptor mediation of acute ketamine application on in vitro gamma oscillations in mouse prefrontal cortex: modeling gamma band oscillation abnormalities in schizophrenia

Schizophrenia (Sz), along with other neuropsychiatric disorders, is associated clinically with abnormalities in neocortical gamma frequency (30-80 Hz) oscillations. In Sz patients, these abnormalities include both increased and decreased gamma activity, and show a strong association with Sz symptoms. For several decades, administration of sub-anesthetic levels of ketamine has provided the most comprehensive experimental model of Sz-symptoms. While acute application of ketamine precipitates a psychotic-like state in a number of animal models, as well as humans, the underlying mechanisms behind this effect, including alteration of neuronal network properties, are incompletely understood, making an in vitro level analysis particularly important. Previous in vitro studies have had difficulty inducing gamma oscillations in neocortical slices maintained in submerged-type recording chambers necessary for visually guided whole-cell recordings from identified neurons. Consequently, here, we validated a modified method to evoke gamma oscillations using brief, focal application of the glutamate receptor agonist kainate (KA), in slices prepared from mice expressing green fluorescent protein in GABAergic interneurons (GAD67-GFP knock-in mice). Using this method, gamma oscillations dependent on activation of AMPA and GABA(A) receptors were reliably elicited in slices containing mouse prelimbic cortex, the rodent analogue of the human dorsolateral prefrontal cortex. Examining the effects of ketamine on this model, we found that bath application of ketamine significantly potentiated KA-elicited gamma power, an effect mimicked by selective NMDAR antagonists including a selective antagonist of NMDARs containing the NR2B subunit. Importantly, ketamine, unlike more specific NMDAR antagonists, also reduced the peak frequency of KA-elicited oscillatory activity. Our findings indicate that this effect is mediated not through NMDAR, but through slowing the decay kinetics of GABA(A) receptor-mediated inhibitory postsynaptic currents in identified GABAergic interneurons. These in vitro findings may help explain the complexities of gamma findings in clinical studies of Sz and prove useful in developing new therapeutic strategies.

Synaptology of ventral CA1 and subiculum projections to the basomedial nucleus of the amygdala in the mouse: relation to GABAergic interneurons

GABAergic neurons of the amygdala are thought to play a critical role in establishing networks for feedback and feedforward inhibition and in mediating rhythmic network activity patterns relevant for emotional behavior, determination of stimulus salience, and memory strength under stressful experiences. These functions are typically fulfilled in interplay of amygdala and hippocampus. Therefore, we explored the putative connectivity of GABAergic neurons with the hippocampo-amygdalar projection with the anterograde tracers Phaseolus vulgaris leucoagglutinin (Phal) and Miniruby injected to GAD67-GFP knock-in mice in which GABAergic neurons are labeled by the expression of the gene for green fluorescent protein (GFP) inserted to the GAD1 gene locus (Tamamaki et al. J Comp Neurol 467:60-79, 2003). We found that, while hippocampal axons target all nuclei of the amygdala, the densest fiber plexus was found in the posterior basomedial nucleus. Electron microscopy revealed that the vast majority of contacts in this nucleus were formed by thin fibers making small asymmetrical contacts, predominantly on GFP-negative profiles. However, several asymmetrical contacts could also be seen on GFP-positive profiles. A surprising result was the occasional occurrence of anterogradely labeled symmetrical synapses indicating a GABAergic contribution to the projection from the hippocampus to the amygdala. While hippocampal input to the amygdala appears to be largely excitatory and targets non-GABAergic neurons, our data provide evidence for a direct involvement of GABAergic neurons in the interplay of these regions, either as target in the amygdala or as projection neurons from the hippocampus. These particular "interface neurons" may be of relevance for the information processing in the amygdalo-hippocampal system involved in emotional behavior and memory formation.

Kv3.1b and Kv3.3 channel subunit expression in murine spinal dorsal horn GABAergic interneurones

GABAergic interneurones, including those within spinal dorsal horn, contain one of the two isoforms of the synthesizing enzyme glutamate decarboxylase (GAD), either GAD65 or GAD67. The physiological significance of these two GABAergic phenotypes is unknown but a more detailed anatomical and functional characterization may help resolve this issue. In this study, two transgenic Green Fluorescent Protein (GFP) knock-in murine lines, namely GAD65-GFP and GAD67-GFP (Δneo) mice, were used to profile expression of Shaw-related Kv3.1b and Kv3.3 K(+)-channel subunits in dorsal horn interneurones. Neuronal expression of these subunits confers specific biophysical characteristic referred to as 'fast-spiking'. Immuno-labelling for Kv3.1b or Kv3.3 revealed the presence of both of these subunits across the dorsal horn, most abundantly in laminae I-III. Co-localization studies in transgenic mice indicated that Kv3.1b but not Kv3.3 was associated with GAD65-GFP and GAD67-GFP immunopositive neurones. For comparison the distributions of Kv4.2 and Kv4.3 K(+)-channel subunits which are linked to an excitatory neuronal phenotype were characterized. No co-localization was found between GAD-GFP +ve neurones and Kv4.2 or Kv4.3. In functional studies to evaluate whether either GABAergic population is activated by noxious stimulation, hindpaw intradermal injection of capsaicin followed by c-fos quantification in dorsal horn revealed co-expression c-fos and GAD65-GFP (quantified as 20-30% of GFP +ve population). Co-expression was also detected for GAD67-GFP +ve neurones and capsaicin-induced c-fos but at a much reduced level of 4-5%. These data suggest that whilst both GAD65-GFP and GAD67-GFP +ve neurones express Kv3.1b and therefore may share certain biophysical traits, their responses to peripheral noxious stimulation are distinct.

Successful treatment for a case of near-fatal secondary adrenal insufficiency

A thirty-six-year old female with shock was found to be unconsciousness a few days after developing a respiratory infection. Her past medical history included autoimmune hypothyroidism. Her state of shock was not controlled by massive fluid resuscitation with a vasopressor and antibiotics. However an infusion of 250 mg methylprednisolone dramatically improved her shock state. Further examination indicated secondary acute adrenal insufficiency. Adrenal insufficiency may complicate other endocrine disorders. Accordingly, a physician should consider hypoadrenocorticism, when patients are in a state of refractory shock in spite of massive infusion with a vasopressor especially in patients with other endocrine disorders.

Mechanisms underlying ketamine-induced synaptic depression in rat hippocampus-medial prefrontal cortex pathway

The non-competitive N-methyl-D-aspartate NMDA receptor antagonist ketamine, a dissociative anesthetic capable of inducing analgesia, is known to have psychotomimetic actions, but the detailed mechanisms remain unclear because of its complex properties. The present study elucidated neural mechanisms of the effect of ketamine, at doses that exert psychotomimetic effects without anesthetic and analgesic effects, by evaluating cortical synaptic responses in vivo. Systemic administration (i.p.) of low (1 and 5 mg/kg), subanesthetic (25 mg/kg) and anesthetic (100 mg/kg) doses of ketamine dose-dependently decreased hippocampal stimulation-evoked potential in the medial prefrontal cortex (mPFC) in freely moving rats. The behavioral analysis assessed by prepulse inhibition (PPI) of acoustic startle response showed that ketamine (5 and 25 mg/kg, i.p.) produced PPI deficit. Thus, the psychotomimetic effects observed in ketamine-treated groups (5 and 25 mg/kg, i.p.) are associated with the induction of synaptic depression in the hippocampus-mPFC neural pathway. Based on these results, we further examined the underlying mechanisms of the ketamine-induced synaptic depression under anesthesia. Ketamine (5 and 25 mg/kg, i.p.) caused increases in dialysate dopamine in the mPFC in anesthetized rats. Moreover, the ketamine-induced decreases in the evoked potential, at the dose 5 mg/kg which has no anesthetic and analgesic effects, were indeed absent in dopamine-lesioned rats pretreated with 6-hydroxydopamine (6-OHDA; 150 μg/rat, i.c.v.). Ketamine (5 mg/kg, i.p.)-induced synaptic depression was blocked by pretreatment with dopamine D1 receptor antagonist SCH 23390 (10 μg/rat, i.c.v.) but not dopamine D2 receptor antagonist haloperidol (1.5 mg/kg, i.p.), suggesting that dopaminergic modulation mediated via D1 receptors are involved in the synaptic effects of ketamine. Furthermore, ketamine (5 mg/kg, i.p.)-induced synaptic depression was prevented also by GABAA receptor antagonist bicuculline (0.2 or 2 μg/rat, i.c.v.). These findings suggest that ketamine at the dose that exerts psychotomimetic symptoms depresses hippocampus-mPFC synaptic transmission through mechanisms involving dopaminergic modulation mediated via D1 receptors, which may lead to a net augmentation of synaptic inhibition mediated via GABAA receptors.

Influence of thyroid hormones and transforming growth factor-β1 on cystatin C concentrations

Serum cystatin C concentrations are reported to increase in the hyperthyroid state. Serum concentrations of cystatin C and transforming growth factor-β1 (TGF-β1) were measured in patients with thyroid dysfunction, and the effects of 3,5,3'-tri-iodothyronine (T(3)) and TGF-β1 on cystatin C production in human hepatoblastoma (Hep G2) cells were studied. Serum concentrations of cystatin C and TGF-β1 were significantly higher in patients with Graves' disease compared with control subjects. Significantly positive correlations were observed between thyroid hormones and cystatin C, thyroid hormones and TGF-β1, and TGF-β1 and cystatin C in patients with thyroid dysfunction. Serum concentrations of cystatin C and TGF-β1 decreased after treatment for hyperthyroidism. Cystatin C mRNA levels and cystatin C secretion were increased by T(3) and TGF-β1 in cultured Hep G2 cells. These results suggest that serum cystatin C concentrations increase in patients with hyperthyroidism. The mechanisms for this may involve elevation of serum TGF-β1 levels and the stimulatory effects of T(3) and TGF-β1 on cystatin C production.

GAD67-GFP+ neurons in the Nucleus of Roller: a possible source of inhibitory input to hypoglossal motoneurons. I. Morphology and firing properties

In this study we examined the electrophysiological and morphological properties of inhibitory neurons located just ventrolateral to the hypoglossal motor (XII) nucleus in the Nucleus of Roller (NR). In vitro experiments were performed on medullary slices derived from postnatal day 5 (P5) to P15 GAD67-GFP knock-in mouse pups. on cell recordings from GFP+ cells in NR in rhythmic slices revealed that these neurons are spontaneously active, although their spiking activity does not exhibit inspiratory phase modulation. Morphologically, GFP+ cells were bi- or multipolar cells with small- to medium-sized cell bodies and small dendritic trees that were often oriented parallel to the border of the XII nucleus. GFP+ cells were classified as either tonic or phasic based on their firing responses to depolarizing step current stimulation in whole cell current clamp. Tonic GFP+ cells fired a regular train of action potentials (APs) throughout the duration of the pulse and often showed rebound spikes after a hyperpolarizing step. In contrast, phasic GFP+ neurons did not fire throughout the depolarizing current step but instead fired fewer than four APs at the onset of the pulse or fired multiple APs, but only after a marked delay. Phasic cells had a significantly smaller input resistance and shorter membrane time constant than tonic GFP+ cells. In addition, phasic GFP+ cells differed from tonic cells in the shape and time course of their spike afterpotentials, the minimum firing frequency at threshold current amplitude, and the slope of their current-frequency relationship. These results suggest that GABAergic neurons in the NR are morphologically and electrophysiologically heterogeneous cells that could provide tonic inhibitory synaptic input to HMs.

Early stress exposure impairs synaptic potentiation in the rat medial prefrontal cortex underlying contextual fear extinction

Traumatic events during early life may affect the neural systems associated with memory function, including extinction, and lead to altered sensitivity to stress later in life. We recently reported that changes in prefrontal synaptic efficacy in response to extinction trials did not occur in adult rats exposed to early postnatal stress (i.e. footshock [FS] stress during postnatal day 21-25 [3W-FS group]). However, identifying neurocircuitry and neural mechanisms responsible for extinction retrieval after extinction training have not been precisely determined. The present study explored whether synaptic transmission in the hippocampal-medial prefrontal cortex (mPFC) neural pathway is altered by extinction retrieval on the day after extinction trials using electrophysiological approaches combined with behavioral analysis. We also elucidated the effects of early postnatal stress on the synaptic response in this neural circuit underlying extinction retrieval. Evoked potential in the mPFC was enhanced following extinction retrieval, accompanied by reduced freezing behavior. This synaptic facilitation (i.e. a long-term potentiation [LTP]-like response) did not occur; rather synaptic inhibition was observed in the 3W-FS group, accompanied by sustained freezing. The behavioral deficit and synaptic inhibition observed in the 3W-FS group were time-dependently ameliorated by the partial N-methyl-D-aspartate (NMDA) receptor agonist D-cycloserine (15 mg/kg, i.p.). These findings suggest that the LTP-like response in the hippocampal-mPFC pathway is associated with extinction retrieval of context-dependent fear memory. Early postnatal stress appears to induce neurodevelopmental dysfunction of this neural circuit and lead to impaired fear extinction later in life. The present data indicate that psychotherapy accompanied by pharmacological interventions that accelerate and strengthen extinction, such as d-cycloserine treatment, may have therapeutic potential for the treatment of anxiety disorders, including posttraumatic stress disorder.

Phagocytosis plays a dual role in activating dendritic cells; digestive production of active Toll-like receptor ligands and cooperation with Toll-like receptor signaling

Phagocytosis is an initial step in innate immunity, which is also stimulated by signals via Toll-like receptors (TLRs); however, the cooperation of phagocytosis with signals through TLRs to establish acquired immunity is unknown. We found that phagocytosis is an essential process to induce an immune reaction against an insoluble TLR ligand. Cell-wall skeleton prepared from Mycobacterium bovis BCG (BCG-CWS), an insoluble TLR2 ligand, activated and matured murine splenic dendritic cell (DC) line BC-1 as well as a soluble TLR2 ligand, Pam3CSK4. Surprisingly, BC-1 maturation with BCG-CWS was completely suppressed by inhibiting phagocytosis, while that with Pam3CSK4 was not affected. Moreover, BCGCWS induced intense delayed-type hypersensitivity (DTH) reactions against mitomycin C-inactivated Lewis lung carcinoma cells but Pam3CSK4 did not. These results suggested that the phagocytosis process enables the insoluble TLR2 ligand to activate DCs via TLR2 comparable to a soluble TLR2 ligand in vitro, and stimulating TLR2 alone is not sufficient to establish T cell-mediated immunity in vivo. It is therefore conceivable that the process of phagocytosis induces additional effects on TLR2-stimulated DCs to activate cellmediated immunity in vivo.

Distribution and role of Kv3.1b in neurons in the medial septum diagonal band complex

The medial septum diagonal band complex (MS/DB) projects via cholinergic and GABAergic pathways to the hippocampus and plays a key role in the hippocampal theta rhythm. In the MS/DB we have previously described a population of fast spiking GABAergic neurons that contain parvalbumin and mediate theta frequency activity in vitro. The Kv3.1 potassium channel is a delayed rectifier channel that plays a major role in fast spiking neurons in the CNS, and has previously been localized in the MS/DB. To determine which cell types in the MS/DB express the Kv3.1b ion channel subunit, transgenic mice in which the expression of GABAergic and glutamate markers are associated with the expression of green fluorescent protein (GFP; GAD67-GFP and VGluT2-GFP mice, respectively) were used for immunofluorescence and axonal tract tracing. Electrophysiological studies were also carried out on rat MS/DB slices to examine the role of the Kv3.1 channel in theta frequency oscillations. The results for the MS/DB were as follows: (1) cholinergic cells did not express GFP in either GAD67-GFP or VGluT2-GFP mice, and there was GAD67 immunoreactivity in GFP-positive neurons in GAD67-GFP mice and in a small proportion (6%) of GFP-positive neurons in VGluT2-GFP mice. (2) Kv3.1b immunofluorescence was associated with the somata of GABAergic neurons, especially those that contained parvalbumin, and with a minority of glutamatergic neurons, but not with cholinergic neurons, and with GABAergic axonal terminal-like processes around certain GABAergic neurons. (3) Both Kv3.1b-positive and -negative GABAergic neurons were septo-hippocampal, and there was a minor projection to hippocampus from VGluT2-GFP neurons. (4) Kainate-induced theta oscillations in the MS/DB slice were potentiated rather than inhibited by the Kv3.1 blocker 4-aminopyridine, and this agent on its own produced theta frequency oscillations in MS/DB slices that were reduced by ionotropic glutamate and GABA receptor antagonists and abolished by low extracellular calcium. These studies confirm the presence of heterogeneous populations of septo-hippocampal neurons in the MS/DB, and suggest that presence of Kv3.1 in the GABAergic neurons does not contribute to theta activity through fast spiking properties, but possibly by the regulation of transmitter release from axonal terminals.

A case of pulmonary oedema induced by suffocation

A 57-year old female civilian was suffocated by an intruder The victim (experienced severe dyspnoea) but violently resisted the assault. Two hours after this event, on admission to a Trauma Centre, she demonstrated left facial swelling with low percutaneous oxygen saturation. Chest X-ray and computed tomography demonstrated pulmonary oedema. This improved dramatically within a short time and she was discharged on the 5th hospital day. Pulmonary oedema induced by suffocation has been reported only rarely. The possible mechanisms by which pulmonary oedema might form after the relief of airway obstruction are discussed.

Isolation and characterization of the plant glsA promoter from Alstroemeria

The differentiation of a vegetative cell and a generative cell is a critical event during pollen development. The Lilium GlsA is known to localize in pollen and is considered to be involved in development of the generative cell. Here, we cloned a glsA ortholog from Alstroemeria, a commercially important cut flower. The expression of AaglsA (Alstroemeria aurea glsA) transcripts increased gradually after pollen mitosis I (PMI) and reached a significant level when the generative cell started to elongate. Analysis of the promoter of AaglsA suggests that AaglsA expression is controlled by several cis-regulatory elements during pollen development. This is the first investigation of reproductive factors regulating male gametogenesis in Alstroemeria.

Fluorescent labeling of both GABAergic and glycinergic neurons in vesicular GABA transporter (VGAT)-venus transgenic mouse

Inhibitory neurons play important roles in a number of brain functions. They are composed of GABAergic neurons and glycinergic neurons, and vesicular GABA transporter (VGAT) is specifically expressed in these neurons. Since the inhibitory neurons are scattered around in the CNS, it is difficult to identify these cells in living brain preparations. The glutamate decarboxylase (GAD) 67-GFP knock-in mouse has been widely used for the identification of GABAergic neurons, but their GAD67 expression was decreased compared to the wild-type mice. To overcome such a problem and to highlight the function and morphology of inhibitory neurons, we generated four lines of VGAT-Venus transgenic mice (lines #04, #29, #39 and #49) expressing Venus fluorescent protein under the control of mouse VGAT promoter. We found higher expression level of Venus transcripts and proteins as well as brighter fluorescent signal in line #39 mouse brains, compared to brains of other lines examined. By Western blots and spectrofluorometric measurements of forebrain, the line #39 mouse showed stronger GFP immunoreactivity and brighter fluorescent intensity than the GAD67-GFP knock-in mouse. In addition, Venus was present not only in somata, but also in neurites in the line #39 mouse by histological studies. In situ hybridization analysis showed that the expression pattern of Venus in the line #39 mouse was similar to that of endogenous VGAT. Double immunostaining analysis in line #39 mouse showed that Venus-expressing cells are primarily immunoreactive for GABA in cerebral cortex, hippocampus and cerebellar cortex and for GABA or glycine in dorsal cochlear nucleus. These results demonstrate that the VGAT-Venus line #39 mouse should be useful for studies on function and morphology of inhibitory neurons in the CNS.

Preferential labeling of inhibitory and excitatory cortical neurons by endogenous tropism of adeno-associated virus and lentivirus vectors

Despite increasingly widespread use of recombinant adeno-associated virus (AAV) and lentiviral (LV) vectors for transduction of neurons in a wide range of brain structures and species, the diversity of cell types within a given brain structure is rarely considered. For example, the ability of a vector to transduce neurons within a brain structure is often assumed to indicate that all neuron types within the structure are transduced. We have characterized the transduction of mouse somatosensory cortical neuron types by recombinant AAV pseudotyped with serotype 1 capsid (rAAV2/1) and by recombinant lentivirus pseudotyped with the vesicular stomatitis virus (VSV) glycoprotein. Both vectors used human synapsin (hSyn) promoter driving DsRed-Express. We demonstrate that high titer rAAV2/1-hSyn efficiently transduces both cortical excitatory and inhibitory neuronal populations, but use of lower titers exposes a strong preference for transduction of cortical inhibitory neurons and layer 5 pyramidal neurons. In contrast, we find that VSV-G-LV-hSyn principally labels excitatory cortical neurons at the highest viral titer generated. These findings demonstrate that endogenous tropism of rAAV2/1 and VSV-G-LV can be used to obtain preferential gene expression in mouse somatosensory cortical inhibitory and excitatory neuron populations, respectively.

Behavioral effects and pattern of brain c-fos mRNA induced by 2,5-dihydro-2,4,5-trimethylthiazoline, a component of fox feces odor in GAD67-GFP knock-in C57BL/6 mice

Predator odors, which are non-intrusive and naturalistic stressors of high ethological relevance, were used to study the neurobiology of innate fear in rodents. The present study investigates behavioral effects and the induction of c-fos mRNA in adult male predator naive mice caused by acute exposure to 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), a component of the fox feces odor. On the behavioral level, TMT potently increased unconditioned freezing and decreased non-defensive grooming behavior. With quantitative real time PCR we established a strong TMT-induced activation in the bed nucleus of the stria terminalis (BNST) (eight-fold increase, p<0.016) and in the ventral olfactory bulb (two-fold increase, p<0.036). In contrast, no significant TMT-induced c-fos induction could be observed in the dorsal olfactory bulb or in the amygdala. Our results display robust fear responses of GAD67-GFP knock-in mice exposed to TMT and suggest that the ventral olfactory bulb and the BNST are strongly activated during the elicitation of fear through predator odor in these transgenic mice.

Noradrenergic excitation of a subpopulation of GABAergic cells in the basolateral amygdala via both activation of nonselective cationic conductance and suppression of resting K+ conductance: a study using glutamate decarboxylase 67-green fluorescent protein knock-in mice

GABAergic interneurons play central roles in the regulation of neuronal activity in the basolateral nucleus of the amygdala (BLA). They are also suggested to be the principal targets of the brainstem noradrenergic afferents which are involved in the enhancement of the BLA-related memory. In addition, behavioral stress has been shown to impair noradrenergic facilitation of GABAergic transmission. However, the noradrenaline (NA) effects in the BLA have not been differentiated among medium- to large-sized GABAergic neurons and principal cells, and remain to be elucidated in terms of their underlying mechanisms. Glutamate decarboxylase 67 (GAD67) is a biosynthetic enzyme of GABA and is specifically expressed in GABAergic neurons. To facilitate the study of the NA effects on GABAergic neurons in live preparations, we generated GAD67-green fluorescent protein (GFP) knock-in mice, in which GFP was expressed under the control of an endogenous GAD67 gene promoter. Here, we show that GFP was specifically expressed in GABAergic neurons in the BLA of this GAD67-GFP knock-in mouse. Under whole-cell patch-clamp recordings in vitro, we identified a certain subpopulation of GABAergic neurons in the BLA chiefly on the basis of the electrophysiological properties. When depolarized by a current injection, these neurons, which are referred to as type A, generated action potentials at relatively low frequency. We found that NA directly excited type-A cells via alpha1-adrenoceptors, whereas its effects on the other types of neurons were negligible. Two ionic mechanisms were involved in this excitability: the activation of nonselective cationic conductance and the suppression of the resting K+ conductance. NA also increased the frequency of spontaneous IPSCs in the principal cells of the BLA. It is suggested that the NA-dependent excitation of type-A cells attenuates the BLA output for a certain period.

Reduced carbohydrate intake in citrin-deficient subjects

Citrin is the liver-type aspartate-glutamate carrier that resides within the inner mitochondrial membrane. Citrin deficiency (due to homozygous or compound heterozygous mutations in the gene SLC25A13) causes both adult-onset type II citrullinaemia (CTLN2) and neonatal intrahepatic cholestasis (NICCD). Clinically, CTLN2 is characterized by hyperammonaemia and citrullinaemia, whereas NICCD has a much more varied and transient presentation that can include multiple aminoacidaemias, hypoproteinaemia, galactosaemia, hypoglycaemia, and jaundice. Personal histories from CTLN2 patients have repeatedly described an aversion to carbohydrate-rich foods, and clinical observations of dietary and therapeutic outcomes have suggested that their unusual food preferences may be directly related to their pathophysiology. In the present study, we monitored the food intake of 18 Japanese citrin-deficient subjects whose ages ranged from 1 to 33 years, comparing them against published values for the general Japanese population. Our survey confirmed a marked decrease in carbohydrate intake, which accounts for a smaller proportion of carbohydrates contributing to the total energy intake (PFC ratio) as well as a shift towards a lower centile distribution for carbohydrate intake relative to age- and sex-matched controls. These results strongly support an avoidance of carbohydrate-rich foods by citrin-deficient patients that may lead to worsening of symptoms.

Abnormal response of the extremities to pain stimulation immediately after the return of spontaneous circulation from cardiopulmonary arrest

OBJECTIVE

A study was undertaken to investigate retrospectively whether or not the appearance of an extensor reaction to pain stimulation immediately after the return of spontaneous circulation (ROSC) from cardiopulmonary arrest (CPA) is a sign of a favourable outcome.

METHODS

Eighty-six patients, all of whom obtained ROSC and survived more than 1 week, were included in the study. They were divided into three groups: (1) patients with at least one abnormal response of the extremities to pain stimulation within 120 min after CPA (M = 2,3 group); (2) patients with no motor response to pain stimulation (M = 1 group); and (3) patients with only motor responses >3 on the Glasgow Coma Scale (M = 4-6 group). The following variables were investigated: prehospital setting, neurological findings on arrival, use of induced hypothermic therapy and outcome. The outcome was defined as the best cerebral performance achieved at any time within 1 month of the CPA and classified by analogy with cerebral performance category (CPC) into two groups: (1) good recovery, CPC 1-3; (2) poor recovery, CPC 4-5.

RESULTS

The proportion of patients given induced hypothermic therapy in the M = 2,3 group was greater than in the M = 1 and M = 4-6 groups. Convulsions occurred more frequently in the M = 1 group than in the M = 2,3 and M = 4-6 groups. The proportion of patients making a good recovery in the M = 1 group (16%; 95% CI 6% to 26%) was smaller than in the M = 2,3 (81%; 95% CI 68% to 95%) and M = 4-6 groups (88%; 95% CI 72% to 100%). The proportion who survived in each group was similar (M = 1 group: 75% (95% CI 60% to 89%); M = 2,3 group: 90% (95% CI 81% to 100%); M = 4-6 group: 76% (95% CI 55% to 97%)). In the M = 2,3 group, four of the five subjects with convulsions did not regain consciousness while 93% (95% CI 83% to 100%) of the subjects in this group without convulsions did regain consciousness.

CONCLUSION

An abnormal response of the extremities to pain stimulation immediately after ROSC tends to be a sign of a favourable outcome in patients without convulsions.

Effect of high fat diet on NKT cell function and NKT cell-mediated regulation of Th1 responses

Diet is one of the important factors that modulate immune responses. In the present study, we have examined the capacity of dietary lipids to modify immune responses in mice and we have investigated the contribution of glycolipid-reactive natural killer T (NKT) cells in this process. Mice fed, high fat diet (HFD; 21.2% fat, 0.20% cholesterol) for 3 weeks, as compared with mice fed standard fat diet (SFD; 4.3% fat, 0.03% cholesterol), showed significantly reduced interferon-gamma production in sera at 6 or 12 h after intraperitoneal injection of an NKT cell ligand, alpha-galactosylceramide. In contrast, production of interleukin-13 was significantly higher at 2 and 6 h in HFD fed mice compared with mice on SFD. No difference was detected in the serum interleukin-4 levels between these two groups of animals. The proportion of NKT cells in spleen and liver was reduced in mice fed HFD compared with those on SFD. In addition, activation of NKT cells assessed by up-regulation of CD69 was suppressed specifically in liver from mice fed HFD. Recall responses of conventional T cells and delayed-type hypersensitivity (Th1 type) against ovalbumin were significantly suppressed in mice fed HFD in comparison with those fed SFD. This suppression was not observed in CD1d-/- mice, suggesting that NKT cells in mice fed HFD played a role in suppressing Th1 responses. Taken together, our findings suggest a critical link between NKT cells, dietary lipid and adaptive immune responses.

Moyamoya disease associated with positive findings for rheumatoid factor and myeloperoxidase-anti-neutrophil cytoplasmic antibody

A 39-year old female suddenly fell into a state of unconsciousness. She had no significantpast medical history. A computed tomography scan of the head demonstrated a massive left putaminal haemorrhage with a ventricular perforation, low density areas in the right frontal lobe, corona radiata and occipital lobe. A single emergency burr hole drainage of the haematoma was performed. Bilateral common carotid arteriograms showed stenosis of the right internal carotid artery and a complete obstruction of left internal carotid artery which were both accompanied by moyamoya vessels. The biochemical studies indicated serological positive findings for RF and MPO-ANCA. She was transferred to another hospital for nursing care in a vegetative state on the 163nd hospital day. This case indicates that immunological factors, inflammation or vasculitis might have possibly been associated with the development of either an obstruction or stenosis of the intracranial internal carotid arteries.

GABAergic phenotype of periglomerular cells in the rodent olfactory bulb

Periglomerular (PG) cells in the rodent olfactory bulb are heterogeneous anatomically and neurochemically. Here we investigated whether major classes of PG cells use gamma-aminobutyric acid (GABA) as a neurotransmitter. In addition to three known subtypes of PG cells expressing tyrosine hydroxylase (TH), calbindin D-28k (CB), and calretinin (CR), we identified a novel PG cell population containing the GABAA receptor alpha5 subunit. Consistent with previous studies in the rat, we found that TH-positive cells were also labeled with antibodies against GABA, whereas PG cells expressing CB or the alpha5 subunit were GABA-negative. Using GAD67-GFP knockin mice, we found that all PG cell subtypes expressed GAD67-GFP. Calretinin labeled the major fraction (44%) of green fluorescent protein (GFP)-positive cells, followed by TH (16%), CB (14%), and the alpha5 subunit (13%). There was no overlap between these neuronal populations, which accounted for approximately 85% of GAD67-GFP-positive cells. We then demonstrated that PG cells labeled for TH, CB, or CR established dendrodendritic synapses expressing glutamic acid decarboxylase (GAD) or the vesicular inhibitory amino acid transporter, VGAT, irrespective of their immunoreactivity for GABA. In addition, CB-, CR-, and TH-positive dendrites were apposed to GABAA receptor clusters containing the alpha1 or alpha3 subunits, which are found in mitral and tufted cells, and the alpha2 subunit, which is expressed by PG cells. Together, these findings indicate that all major subtypes of PG cells are GABAergic. In addition, they show that PG cells provide GABAergic input to the dendrites of principal neurons and are interconnected with other GABAergic interneurons, which most likely are other PG cells.

Respiratory activity in brainstem of fetal mice lacking glutamate decarboxylase 65/67 and vesicular GABA transporter

The respiratory neural network in the mammalian medulla oblongata shows rhythmic activity before birth. GABA and glycine are considered to be involved in control of respiratory rhythm. Recently we have demonstrated respiratory failure in glutamic acid decarboxylase (GAD) 67-deficient mice [Tsunekawa N, Arata A, Obata K (2005) Development of spontaneous mouth/tongue movement and related neural activity, and their repression in mouse fetus lacking glutamate decarboxylase 67. Eur J Neurosci 21:173-178]. To further evaluate the involvement of GABA and glycine in fetal respiratory function, we studied neural activities in brainstem-spinal cord blocks prepared from GAD65-/-:67-/- and vesicular GABA transporter (VGAT)-/-mice on embryonic day 14 (E14)-E15 and E18. In these knockout mice, the synthesis of GABA and the vesicular release of GABA and glycine are completely absent, respectively. Spontaneous respiratory discharges were observed in the ventral roots at the cervical cord (C) 4 level from wild-type mice but not from the knockout mice on E18. Administration of substance P induced C4 discharges in GAD65-/-:67-/- preparations but not in VGAT-/- preparations. C4 discharges were observed in the knockout mice on E14-E15, although the frequency was lower than that in the wild-type. Neuronal activities in the respiratory network of the E18 brainstem were recorded using a "blind" patch-clamp technique. Expiratory and inspiratory neurons with their characteristic firing patterns were observed in the wild-type fetuses. Strychnine reversed inspiratory-phase hyperpolarization to large depolarization in expiratory neurons. On the other hand, neurons in the same area of the knockout mice fired spontaneously without any rhythm. Substance P induced hyperpolarizing potentials in medullary neurons of GAD65-/-:67-/- mice. Further administration of strychnine induced large depolarizing potentials. Rhythmic activities were not observed in VGAT-/- mice even in the presence of substance P and strychnine. These results indicate that the lack of GABA and glycine impairs the function of the respiratory network in mouse fetuses and the impairment progresses with fetal age.

Calcium-dependent NMDA-induced dendritic injury and MAP2 loss in acute hippocampal slices

Excessive glutamate receptor stimulation can produce rapid disruption of dendritic morphology, including dendritic beading. We recently showed that transient N-methyl-d-aspartic acid (NMDA) exposure resulted in irreversible loss of synaptic function and loss of microtubule associated protein 2 (MAP2) from apical dendrites. The present study examined the initiation and progression of dendritic injury in mouse hippocampal slices following this excitotoxic stimulus. NMDA exposure (30 microM, 10 min) produced irregularly shaped dendritic swellings, evident first in distal apical dendrite branches, and later (20-90 min) involving most proximal dendrites. Over the same time course, immunoreactivity for the microtubule-associated protein MAP2 was progressively lost from apical dendrites, and increased in CA1 somata. This damage and MAP2 loss was Ca2+-dependent, and was not reversible within the time course of these experiments (90 min post-NMDA washout). Formation of regularly-spaced, spherical dendritic varicosities (dendritic beading) was rarely observed, except when NMDA was applied in Ca2+-free ACSF. Under these conditions, beading appeared predominant in interneurons, as assessed from experiments with GAD67-GFP (Deltaneo) mice. Ca2+-removal was associated with significantly better preservation of dendritic structure (MAP2) following NMDA exposure, and other ionic fluxes (sensitive to Gd3+ and spermine) may contribute to residual damage occurring in Ca2+-free conditions. These results suggest that irregularly shaped dendritic swelling is a Ca2+-dependent degenerative event that may be quite different from Ca2+-independent dendritic beading, and can be a predominant type of injury in CA1 pyramidal neurons in slices.

Antigen-presenting cells expressing glutamate decarboxylase 67 were identified as epithelial cells in glutamate decarboxylase 67-GFP knock-in mouse thymus

Glutamate decarboxylase (GAD), which has two isoforms, GAD65, and GAD67, is responsible for synthesis of the major inhibitory neurotransmitter, gamma-aminobutyric acid. GAD is expressed predominantly in the central nervous system; recent reports suggest that GAD is also expressed in non-neuronal organs including the pancreas. In the pancreatic islets, GAD serves as one of the autoantigens in type I diabetes mellitus. Recent flow cytometric analyses have shown that a variety of self-antigens, including GAD, are ectopically transcribed and expressed in particular cell populations of the thymus, although consensus concerning the cellular phenotype has not been obtained. The aim of this study was to clarify the localization and cellular phenotype of GAD67-expressing cells in the thymus at a cellular level with a novel approach using GAD67-green fluorescent protein (GFP) knock-in mice, in which GFP is expressed specifically in GAD67-positive cells. GFP-positive cells were detected in the thymic medulla and were identified as epithelial cells by immunohistochemistry. Almost all GFP-positive cells were positive for major histocompatibility complex (MHC) class II antigen staining and were positive for both cytokeratin and Ulex Europaeus Agglutinin I, markers of medullary thymic epithelial cells, but were negative for CD11c, Gr-1, and CD45, markers of dendritic cells, macrophages, and B-lymphocytes, respectively.