Transparency in Human-Machine Mutual Action

Recent advances in human-computer integration (HInt) have focused on the development of human-machine systems, where both human and machine autonomously act upon each other. However, a key challenge in designing such systems is augmenting the user’s physical abilities while maintaining their sense of self-attribution. This challenge is particularly prevalent when both human and machine are capable of acting upon each other, thereby creating a human-machine mutual action (HMMA) system. To address this challenge, we present a design framework that is based on the concept of transparency. We define transparency in HInt as the degree to which users can self-attribute an experience when machines intervene in the users’ action. Using this framework, we form a set of design guidelines and an approach for designing HMMA systems. By using transparency as our focus, we aim to provide a design approach for not only achieving human-machine fusion into a single agent, but also controlling the degrees of fusion at will. This study also highlights the effectiveness of our design approach through an analysis of existing studies that developed HMMA systems. Further development of our design approach is discussed, and future prospects for HInt and HMMA system designs are presented.

Perceptual simultaneity and its modulation during EMG-triggered motion induction with electrical muscle stimulation

When human movement is assisted or controlled with a muscle actuator, such as electrical muscle stimulation, a critical issue is the integration of such induced movement with the person's motion intention and how this movement then affects their motor control. Towards achieving optimal integration and reducing feelings of artificiality and enforcement, we explored perceptual simultaneity through electrical muscle stimulation, which involved changing the interval between intentional and induced movements. We report on two experiments in which we evaluated the ranges between detection and stimulus for perceptual simultaneity achievable with an electromyography-triggered electrical muscle stimulation system. We found that the peak range was approximately 80-160 ms, with the timing of perceptual simultaneity shifting according to different adaptation states. Our results indicate that perceptual simultaneity is controllable using this adaptation strategy.

Morphological characteristics of the vallate papillae of the one-humped camel (Camelus dromedarius)

In this study, the morphology of the vallate papillae of camel was investigated using gross, light and scanning electron microscopy as well as immunohistochemistry. Vallate papillae were arranged along an identical line on each side of the lingual torus and revealed remarkable individual differences. However, each papilla - round or flat, small or large, single or paired - was surrounded by a prominent groove and an annular pad. Based on our findings, postnatal development and formation of new papillae occur in camel. Microscopically, taste buds were constantly observed along the medial wall epithelium, and in the papillary wall epithelium on both sides of the secondary groove apparently separating the vallate papillae. In addition, an aggregation of taste buds was occasionally observed at the bottom of the lateral wall epithelium. Using SEM, we observed several pits and microplicae on the surface of papillae as well as distinct taste pores on the peripheral parts of the dorsal surface. We demonstrated immunoreactivity of α-gustducin only in mature taste buds. We conclude that the morphological features and microstructure of vallate papillae are a characteristic feature in camel compared to other ruminants. These features might have evolved to assist the camel in the manipulation and tasting of thin organic stiff plants that grow in its environment and therefore might have related to the feeding habits of the animal.

Excessive CD4+ T cells co-expressing interleukin-17 and interferon-γ in patients with Behçet's disease

Excessive T helper type 1 (Th1) cell activity has been reported in Behçet's disease (BD). Recently, association of Th17 cells with certain autoimmune diseases was reported, and we thus investigated circulating Th17 cells in BD. CD4(+) CD45RO(-) (naive) T cells were cultured with Th0-, Th1-, Th2- and Th17-related cytokines and antibodies, and their mRNA was studied by real-time polymerase chain reaction (PCR). When naive CD4(+) T cells were cultured with Th1- and Th17-related cytokines, interferon (IFN)-γ mRNA and interleukin (IL)-17 mRNA were up-regulated, respectively, in BD patients. Naive CD4(+) T cells cultured in a Th17 cell-inducing condition expressed IL-23 receptor (IL-23R) mRNA excessively. IL-17 mRNA expression was induced only when naive CD4(+) T cells were cultured in the presence of IL-23. CD4(+) T cells cultured with Th17 cytokines expressed excessive RAR-related orphan receptor C (RORC) mRNA. Using intracellular cytokine staining, we found that CD45RO(+) (memory) CD4(+) T cells producing IL-17 and IFN-γ simultaneously were increased significantly. Memory CD4(+) T cells producing IFN-γ but not IL-17 decreased profoundly in BD patients. CD4(+) T cells producing IL-17 and IFN-γ simultaneously were found in BD skin lesions. Collectively, we found excessive CD4(+) T cells producing IL-17 and IFN-γ (Th1/Th17) cells in patients with BD, and possible involvement of IL-23/IL-23R pathway for the appearance of excessive Th1/Th17 cells.

Skewed TGFβ/Smad signalling pathway in T cells in patients with Behçet's disease

OBJECTIVES

Behçet's disease (BD) is a multi-systemic inflammatory disease, characterised by recurrent oral aphthosis, genital ulcers, skin lesions and uveitis. We have reported excessive Th1 cell activity in patients with BD. More recently, Th17 cells were suggested to associate with several autoimmune diseases. This study was designed to investigate the role of Th17 related cytokines and signalling molecules in patients with BD.

METHODS

We examined mRNA expressions of Th1 and Th17 related cytokines and related signalling molecules in PBMC of 12 patients with BD and 14 normal controls (NC) using quantitative RT-PCR. We studied expressions of the Th17 related cytokines in other four BD patients' skin lesions by immunofluorescence.

RESULTS

Major Th17 related cytokines were not detected in unstimulated PBMC in patients with BD. After stimulation, mRNA expressions of TGFβ receptor type 1, IL-12 receptor β2 and suppressor of cytokine signalling protein (SOCS) 1 on PBMC were significantly enhanced in patients with BD, as compared with NC (p<0.05). mRNA expression of RORC, a key transcription factor for Th17 cell differentiation, was comparable between BD and NC. CD4+ T cells infiltrating into BD skin lesion expressed TGFβ1 much more than those infiltrating into non-Behçet's disease erythema nodosum.

CONCLUSIONS

These findings suggest that TGFβ/Smad signalling pathway of T cells is overactive in patients with BD.

Reperfusion Therapy for Acute Middle Cerebral Artery Trunk Occlusion. Direct Percutaneous Transluminal Angioplasty Versus Intra-arterial Thrombolysis

SUMMARY

The purpose of this study was to test the hypothesis that direct percutaneous transluminal angioplasty (PTA) might reduce the incidence of haemorrhagic complications and might improve recanalization rate and clinical outcome as compared with intra-arterial (IA) thrombolysis in patients with acute middle cerebral artery (MCA) trunk occlusion. A total of 70 patients with acute MCA trunk occlusion were treated with IA reperfusion therapy. Thirty-six patients were treated with IA thrombolysis alone. In the other 34 patients, direct PTA was selected as the first choice of the treatment and subsequent thrombolysis was added if necessary for distal embolization. The modified Rankin scale (mRS) was used to assess clinical outcome at 90 days. As compared with IA thrombolysis, direct PTA provided significant increase in the rates of partial or complete recanalization (63.9 vs 91.2%, p < 0.01) and decrease in the incidence of large parenchymal hematoma with neurological deterioration (19.4% vs 2.9%, p=0.03). Despite such favorable effects, direct PTA did not improve the rate of a favorable outcome (mRS score 0 or 1, 41.7% for the IA thrombolysis group vs 52.9% for the PTA group, p=0.48). However, outcome classified in terms of independence (mRS score </= 2) was significantly better in the PTA group (73.5%) than the IA thrombolysis group (50.0%, p=0.04). In patients with acute MCA trunk occlusion, as compared with IA thrombolysis, direct PTA improved recanalization rate and reduced serious haemorrhagic complications, resulting in a significant increase in independent patients.

Abstract heterarchy: Time/state-scale re-entrant form

A heterarchy is a dynamical hierarchical system inheriting logical inconsistencies between levels. Because of these inconsistencies, it is very difficult to formalize a heterarchy as a dynamical system. Here, the essence of a heterarchy is proposed as a pair of the property of self-reference and the property of a frame problem interacting with each other. The coupling of them embodies a one-ity inheriting logical inconsistency. The property of self-reference and a frame problem are defined in terms of logical operations, and are replaced by two kinds of dynamical system, temporal dynamics and state-scale dynamics derived from the same "liar statement". A modified tent map serving as the temporal dynamics is twisted and coupled with a tent map serving as the state-scale dynamics, and this results in a discontinuous self-similar map as a dynamical system. This reveals that the state-scale and temporal dynamics attribute to the system, and shows both robust and emergent behaviors.

Early CT signs in patients with acute middle cerebral artery occlusion: incidence of contrast staining and haemorrhagic transformations after intra-arterial reperfusion therapy

AIM

To investigate how often early computed tomography (CT) signs are associated with blood-brain barrier (BBB) disruption and result in haemorrhagic transformations.

MATERIALS AND METHODS

Serial CT findings were prospectively evaluated in 61 patients with acute middle cerebral artery (MCA) occlusion who underwent initial CT examination within 3h of stroke onset and who were treated with intra-arterial reperfusion therapy within 6h of stroke onset. Obscuration of the margin of the lentiform nucleus and loss of the insular ribbon were evaluated as early CT signs in the deep MCA territories. Cortical effacement was also evaluated. BBB disruption was defined as contrast medium staining in post-therapeutic CT just after reperfusion therapy. The relationship between pre-therapeutic early CT signs and post-therapeutic contrast staining or haemorrhagic transformations was investigated.

RESULTS

The frequency of early CT signs in the deep MCA territories was significantly higher than that of cortical effacement (68.9 versus 27.9%). There were significant correlations between pre-therapeutic early CT signs and post-therapeutic contrast staining in both the deep and superficial MCA territories. Compared with early CT signs in the deep MCA territories, cortical effacement had a significantly higher incidence of post-therapeutic contrast staining (54.8 versus 82.4%). Although not statistically significant, cortical effacement tended to develop into haemorrhagic transformations. There was no correlation between early CT signs in the deep MCA territories and haemorrhagic transformations.

CONCLUSION

Cortical effacement may be an advanced CT sign with BBB disruption and potential risk for haemorrhagic transformations. The presence of early CT signs in the deep MCA territories may not be a contraindication of reperfusion therapy.

Spontaneous regeneration of the corticospinal tract after transection in young rats: a key role of reactive astrocytes in making favorable and unfavorable conditions for regeneration

We demonstrated the occurrence of marked regeneration of the corticospinal tract (CST) after a single transection and failure of regeneration after a repeated transection in young rats. To provide convincing evidence for the complete transection and regeneration we used retrograde neuronal double labeling. Double-labeled neurons that took up the first tracer from the transection site and the second tracer from the injection site caudal to the transection site were observed in the sensorimotor cortex. The anterograde tracing method revealed various patterns of regeneration. In the most successful cases the vast majority of regenerated fibers descended in the normal tract and terminated normally whereas a trace amount of fibers coursed aberrantly. In the less successful cases fibers descended partly normally and partly aberrantly or totally aberrantly. To clarify the role of astrocytes in determining the success or failure of regeneration we compared expression of glial fibrillary acidic protein (GFAP), vimentin and neurofilament (NF) immunoreactivity (IR) in the lesion between single and repeated transections. In either transection, astrocytes disappeared from the CST near the lesion site as early as 3 h after lesioning. However, by 24 h after a single transection, immature astrocytes coexpressing GFAP- and vimentin-IR appeared in the former astrocyte-free area and NF-positive axons crossed the lesion. By contrast, after a repeated transection the astrocyte-free area spread and NF-positive axons never crossed the lesion. It appears likely that the major sign, and possibly cause of failure of regeneration is the prolonged disappearance of astrocytes in the lesioned tract area.

Correlation between Haemorrhagic Complications and CT Findings before and after Intra-arterial Reperfusion Therapy for Acute Middle Cerebral Artery Occlusion

The purpose of this study was to investigate whether haemorrhagic complications can be predicted by evaluating CT findings before and after intra-arterial reperfusion therapy for acute middle cerebral artery (MCA) occlusion. Pretherapeutic early CT signs within three hours after onset and post-therapeutic contrast extravasation were evaluated in 61 patients treated within six hours after onset. Early CT signs were evaluated in the deep (obscuration of the margin of the lentiform nucleus and loss of the insular ribbon) and superficial MCA territories (cortical effacement). Haemorrhagic transformations were seen in 39.3% of patients, 54.2% of them had both pre-therapeutic early CT signs and post-therapeutic contrast extravasation. Obscuration of the entire lentiform nucleus and the presence of contrast extravasation were reliable predictors for haemorrhagic transformations, and cortical effacement had also a tendency to be associated with haemorrhage. Absence of early CT signs did not always result in the absence of haemorrhagic transformations and 37.5% of haemorrhage occurred in the presumed normal area without early CT signs. On the other hand, absence of post-therapeutic contrast extravasation was a reliable negative predictor for intraparenchymal haematoma.

Aberrant expression of Fas ligand on anti-DNA autoantibody secreting B lymphocytes in patients with systemic lupus erythematosus: "immune privilege"-like state of the autoreactive B cells

BACKGROUND

Fas/Fas ligand (FasL) system has been assigned a pivotal role in the development and maintenance of peripheral tolerance, and mice with defects in their Fas/FasL system develop lupus-like symptoms. In this study we examined FasL expression of peripheral blood lymphocytes in patients with systemic lupus erythematosus (SLE).

METHODS

We assessed FasL mRNA and protein expression by reverse transcription (RT)-PCR and immunoblotting and immunocytochemical staining, respectively, in patients with SLE. Anti-DNA antibody secreting B cells were purified using biotin labeled DNA and streptavidin-bead.

RESULTS

Expression of FasL protein was not or very weakly detected in freshly isolated PBMC in normal individuals. In contrast, freshly isolated SLE PBMC exhibited the enhanced expression of FasL protein without in vitro stimulation. Not only purified T cells but also purified B cells expressed FasL on their cell surface spontaneously. In addition, freshly isolated anti-DNA autoantibody secreting B cells express FasL without in vitro stimulation.

CONCLUSION

The results suggest that autoreactive B lymphocytes which aberrantly express FasL may kill Fas+ immunoregulatory T lymphocytes. Thus aberrantly expressed FasL may facilitate escape of the autoreactive B cells from the immune tolerance system, and may contribute to the sustained secretion of autoantibodies in patients with SLE.

Serial changes in signal intensities of the adjacent discs on T2-weighted sagittal images after surgical treatment of cervical spondylosis: anterior interbody fusion versus expansive laminoplasty

BACKGROUND

There have been many reports about newly developed degenerative changes in the adjacent segments after anterior interbody fusion. It is a controversial issue whether the adjacent-segment disease in patients treated by anterior interbody fusion is the result of progressive cervical spondylosis at the adjacent levels or is caused by the arthrodesis. The aim of this study is to clarify the difference in postoperative effect on the adjacent segments between anterior interbody fusion and expansive laminoplasty.

METHOD

This study included 14 patients who underwent pre- and postoperative MR images at 6 and 12 months. Seven patients underwent cervical interbody fusion and the other 7 patients underwent expansive laminoplasty. Disc degeneration was evaluated semiquantitatively by calculating the degenerative index (DI) that is a ratio of the intensity in the disc to that in the upper cervical cord.

FINDINGS

In the anterior interbody fusion group, the adjacent disc intensities decreased within 12 months (F = 20.42; P < 0.01). The pre-operative mean DI was 0.59 +/- 0.16. The post-operative mean DIs were 0.56 +/- 0.16 at 6 months and 0.47 +/- 0.16 at 12 months. In the expansive laminoplasty group, the signal intensities of both the adjacent discs and the discs within the range of laminoplasty had no serial changes during the same period (F = 2.67; P = 0.09 and F = 0.15; P = 0.87 respectively).

INTERPRETATION

Anterior interbody fusion had a significant influence on the adjacent discs even as soon as 12 months after surgery, but laminoplasty had no influence on them during the same period.

The correlation between 99mTc-MIBI uptake and MIB-1 as a nuclear proliferation marker in glioma--a comparative study with 201Tl

Technetium-99m methoxy-isobutylisonitrile (MIBI), like thallium-201 (201Tl), is a highly efficient agent for the diagnosis and monitoring of glioma tumors. Although 201Tl uptake is known to be partly associated with proliferative activity, little is known about the correlation between MIBI uptake and proliferation activity in gliomas. The current study was performed to assess the correlation between MIBI uptake and proliferative activities in gliomas, estimated by the monoclonal antibody to Ki-67 antigen (MIB-1) staining method. By comparing the results with those of 201Tl, we determined which tracer would be suitable for estimating proliferative activities. Twenty-four presurgical glioma patients (six with low-grade gliomas, five with anaplastic astrocytomas, and 13 with glioblastomas) were given MIBI and 201Tl SPECT. Early (10 min after injection) and delayed images (3 h after injection) were obtained for both MIBI and 201Tl scintigraphy. SPECT parameters, early ratio (ER), delayed ratio (DR), and retention index (RI) were obtained in both radiopharmaceuticals. All patients underwent subsequent surgical excision, and the specimens were immunostained for MIB-1. The proliferative activity was measured as a percentage positive nuclear area for MIB-1 (MI; MIB-1 index). To evaluate the relationship between the proliferative activity and SPECT parameters, we performed a correlation analysis. MI correlated with the MIBI uptake ratio (r = 0.75 for ER, and r = 0.7 for DR). Both DR and RI of 201Tl also correlated with MI, but weakly (r = 0.6 for DR, and. r = 0.59 for RI). There was no significant correlation between the MIB-1 index and the other parameters. MIBI-uptake parameters demonstrated a stronger positive correlation with the MIB-1 index than that of 201Tl. With the use of MIBI SPECT, we can estimate the proliferative activity of glioma noninvasively.

Differentiation of the lingual and palatal gustatory epithelium of the rat as revealed by immunohistochemistry of alpha-gustducin

We used alpha-gustducin, a taste-cell-specific G protein to investigate the onset of taste transduction and its relation to the development of the palatal and lingual taste buds. Frozen cryostat and paraffin sections were prepared from the palatal and lingual gustatory epithelium of the rat from birth till postnatal day 21 (PN 21d). At PN 1-7d, alpha-gustducin-immunoreactive solitary ovoid or bipolar cells were scattered among the oral epithelium either horizontally along the oral surface or vertically oriented between the basal lamina and oral surface. In the circumvallate and foliate papillae, these cells became wrapped in alpha-gustducin-immunonegative cells surrounded by an extracellular space forming a bud-like structure. Simultaneously, different stages of typical taste buds were recognized, but alpha-gustducin was only expressed in some neonatally developed pored buds. At PN 1d, alpha-gustducin was expressed in pored taste buds with a relatively higher frequency recorded in the soft palate as compared with the nasoincisor, circumvallate, and foliate papillae. The immunoreactive cells were spindle shaped with elongated processes extending from the base to the pore of the taste buds. During the second week, the solitary cells could no longer be recognized while the total counts of immunoreactive cells within the taste buds gradually increased. We argue that taste transduction is essentially required from the time of birth and can be fulfilled by both of the solitary chemosensory cells, which are immunoreactive for alpha-gustducin and scattered in the oral epithelium, and the taste cells within the mature taste buds. Moreover, the onset of taste transduction accomplished by the palatal taste buds developed earlier than that achieved by taste buds in the circumvallate and foliate papillae.

Temporal and spatial distribution of Fos protein in the lumbar spinal dorsal horn neurons in the rat with chronic constriction injury to the sciatic nerve

The temporal and spatial expression pattern of Fos protein in spinal dorsal horn neurons was examined by immunohistochemistry in rats with chronic constriction injury (CCI) to the sciatic nerve. In normal animals, a few Fos-immunoreactive (-IR) neurons were detected in the dorsal horn of the lumbar spinal cord. Following induction of CCI, a very large number of Fos-IR neurons appeared in the spinal dorsal horn, but a significant number of Fos-IR neurons were also observed in the contralateral dorsal horn where primary afferents of the injured sciatic nerve rarely project. Sham-operated animals also had a significant number of Fos-IR neurons in the dorsal horn bilaterally. The number of Fos-IR neurons reached its maximal level 1 day following placement of the ligatures (PO 1d). The ratio of the number of Fos-IR neurons in the ipsilateral dorsal horn to the contralateral dorsal horn, however, had its peak level 3 days following CCI (3.1-fold increase compared to the contralateral dorsal horn). The number of Fos-IR neurons in the dorsal horn gradually decreased, but increased again around PO 15d. On PO 30d, the number of Fos-IR neurons decreased and became comparable to that in normal animals. The present results indicate that the induction of Fos-IR neurons in the dorsal horn caused by CCI is biphasic and reaches its maximal level on PO 3d, near the time of hyperalgesia onset.

Parenchymal hyperdensity on computed tomography after intra-arterial reperfusion therapy for acute middle cerebral artery occlusion: incidence and clinical significance

BACKGROUND AND PURPOSE

The purpose of the present study was to assess the incidence and clinical significance of the intraparenchymal hyperdense areas on the posttherapeutic CT scan just after intra-arterial reperfusion therapy.

METHODS

Seventy-seven patients with acute middle cerebral artery occlusion were studied prospectively with post-therapeutic CT. Hyperdense areas were classified into three groups: those in the lentiform nucleus, insular cortex and cerebral cortex. We investigated the incidence of hyperdense areas and hemorrhagic transformations and assessed whether location of hyperdense areas may play a role in the incidence of hemorrhagic transformations. We also evaluated correlation between early CT signs and hyperdense areas.

RESULTS

Forty-five hyperdense areas were seen in 37 of the 77 patients (48.1%): 19 of the 45 (42.2%) were confirmed to be hematomas themselves, 6 (13.4%) showed later conversion to petechial hemorrhages, and 20 (44.4%) showed rapid disappearance without hemorrhagic transformations. Eleven of the 37 patients (29.7%) had neurological worsening due to massive hematoma (symptomatic hemorrhage), whereas none of the 40 patients without hyperdense areas had symptomatic hemorrhage. The incidence of hemorrhage among hyperdense areas was significantly lower in the insular cortex than in the other 2 regions (P<0.01). On the other hand, hyperdense areas in the lentiform nucleus had a significantly higher incidence of neurological worsening (P<0.05). There was a significant correlation between early CT signs and hyperdense areas (P<0.0001).

CONCLUSIONS

The presence of hyperdense areas was a significant risk factor for severe hemorrhagic transformations, although only 29.7% of patients with hyperdense areas had symptomatic hemorrhage. On the contrary, the absence of hyperdense areas was a reliable negative predictor for symptomatic hemorrhage.

Reduced expression of hepatocyte growth factor activator inhibitor type-2/placental bikunin (HAI-2/PB) in human glioblastomas: implication for anti-invasive role of HAI-2/PB in glioblastoma cells

Hepatocyte growth factor activator inhibitor type-2/placental bikunin (HAI-2/PB) is a serine proteinase inhibitor that contains 2 Kunitz-domains and a presumed transmembrane domain. It has broad inhibitory spectra against various serine proteinases showing potent inhibitory activities not only to hepatocyte growth factor activator but also to plasmin, trypsin and kallikreins. In this study, we investigated the expression of HAI-2/PB in human gliomas in vivo and the effects of HAI-2/PB on the fibrinolytic and invasive capabilities of human glioblastoma cells in vitro. With RNA blot analysis, HAI-2/PB mRNA was expressed in normal brain and in low-grade astrocytomas, but was hardly detectable in anaplastic astrocytomas and glioblastomas, indicating that its expression levels were inversely correlated with the histological grade of human gliomas. To further explore the possible role of HAI-2/PB in glioma progression, cultured human glioblastoma cell lines (U251 and YKG-1) were transiently transfected with an expression vector harboring human HAI-2/PB cDNA. Subsequent analysis indicated that the expression of HAI-2/PB suppressed the fibrinolytic activities of both glioblastoma cell lines. Moreover, HAI-2/PB inhibited Matrigel invasion of U251 and YKG-1 cells by 30% and 64%, respectively. This anti-invasive effect appeared to be mediated primarily by the inhibitory activity of HAI-2/PB against the serine proteinase-dependent matrix degradation. These findings suggest that the reduced expression of HAI-2/PB is possibly involved in the progression of human gliomas.

Temporal and spatial distribution of Fos protein in the parabrachial nucleus neurons during experimental tooth movement of the rat molar

The present study was undertaken to reveal spatio-temporal changes in the distribution of Fos-like immunoreactive (-IR) neurons in the parabrachial nucleus (PBN), one of the important relay nuclei for processing autonomic and somatosensory information from the oro-facial regions, following the induction of experimental tooth movement in rat upper molars. The experimental tooth movement was induced by the insertion of elastic rubber between the first and second upper molars. In normal animals, the PBN contained a smaller number of Fos-IR neurons. Following experimental tooth movement, the Fos-IR neurons increased in number significantly on both the ipsilateral and contralateral PBN, reaching a maximum at 4 h (about 10 times that of normal animals), and then decreased gradually. However, a significant number of Fos-IR neurons remained at 24 h post-operation. Remarkable side-by-side differences in the number of Fos-IR neurons were recognized at 1 to 4 h following the experimental tooth movement. Their number returned to normal (basal) levels at 5 days post. All subnuclei of PBN showed similar temporal changes in the number of Fos-IR neurons, this being particularly apparent in lateral PBN. Administrations of morphine (3 and 10 mg/kg, i.p.) drastically reduced the induction of Fos-IR neurons in all subnuclei of both the ipsilateral and contralateral PBN in a dose-dependent manner, and its effect was antagonized by pretreatment with naloxone (2 mg/kg, i.p.). The reduction of Fos-IR neurons by morphine pretreatment suggests that the appearance of Fos-IR neurons in the PBN may be partly due to the noxious stimulation and/or stress arising from tooth movement. The bilateral expression of Fos-IR neurons in the PBN indicates that the experimental tooth movement causes the activation of PBN neurons for the processing of somatosensory as well as autonomic information. The prolonged expression of Fos-IR neurons in all the subnuclei of bilateral PBN reflects clinical features of the transient discomfort and/or abnormal sensations, which many patients often complain about during orthodontic treatment.

Development and maturation of taste buds of the palatal epithelium of the rat: histological and immunohistochemical study

Palatal taste buds are intriguing partners in the mediation of taste behavior and their spatial distribution is functionally important for suckling behavior, especially in the neonatal life. Their prenatal development has not been previously elucidated in the rat, and the onset of their maturation remains rather controversial. We delineated the development and frequency distribution of the taste buds as well as the immunohistochemical expression of alpha-gustducin, a G protein closely related to the transduction of taste stimuli, in the nasoincisor papilla (NIP) and soft palate (SP) from the embryonic day 17 (E17) till the postnatal day 70 (PN70). The main findings in the present study were the development of a substantial number of taste pores in the SP of fetal rats (60.3 +/- 1.7 out of 122.8 +/- 5.5; mean +/- SD/animal at E19) and NIP of neonatal rats (9.8 +/- 1.0 out of 44.8 +/- 2.2 at PN4). alpha-gustducin-like immunoreactivity (-LI) was not expressed in the pored taste buds of either prenatal or newborn rats. The earliest expression of alpha-gustducin-LI was demonstrated at PN1 in the SP (1.5 +/- 0.5 cells/taste bud; mean +/- SD) and at PN4 in the NIP (1.4 +/- 0.5). By age the total counts of pored taste buds continuously increased and their morphological features became quite discernible. They became pear in shape, characterized by distinct pores, long subporal space, and longitudinally oriented cells. Around the second week, a remarkable transient decrease in the total number of taste buds was recorded in the oral epithelium of NIP and SP, which might be correlated with the changes of ingestive behaviors. The total counts of cells showing alpha-gustducin-LI per taste bud gradually increased till the end of our investigation (14.1 +/- 2.7 in NIP and 12.4 +/- 2.5 in SP at PN70). We conclude that substantial development of taste buds began prenatally in the SP, whereas most developed entirely postnatal in the NIP. The present study provides evidence that the existence of a taste pore which is considered an important criterion for the morphological maturation of taste buds is not enough for the onset of the taste transduction, which necessitates also mature taste cells. Moreover, the earlier maturation of palatal taste buds compared with the contiguous populations in the oral cavity evokes an evidence of their significant role in the transmission of gustatory information, especially in the early life of rat.

Large cholesterol granuloma arising from the frontal sinus--case report

A 59-year-old male presented with a large cholesterol granuloma arising from the frontal sinus manifesting as a large, fluctuated, soft mass in his brow, compressing left eye. Skull radiography showed dilation of the frontal sinus. Computed tomography and magnetic resonance imaging revealed a cystic mass extending into the left orbit and anterior cranial fossa. Gross inspection at the frontal craniotomy showed mucinous, dark green fluid intermingled with shining material. The histological diagnosis was cholesterol granuloma with epithelial lining. Large cholesterol granuloma with facial deformity is always associated with bone and cosmetic problems. Wide opening of the frontal sinus followed by cyst wall removal and plastic repair of the skull is necessary.

Long-term enhancement of synaptic transmission induced by veratridine in rat CA3 hippocampal neurons

Veratridine is a neurotoxin that induces persistent activation of sodium channels in excitable cells. We investigated the effects of this toxin on excitatory synaptic transmission in CA3 neurons of juvenile rat hippocampus using whole-cell patch-clamp and field-potential recordings. The population spikes evoked by electrical stimulation of the mossy fiber were gradually enhanced after washout of veratridine (0.3 microM), but they were not enhanced by the co-application of veratridine and an N-methyl-D-aspartate (NMDA) receptor antagonist (D-APV, 30 microM). When a pipette solution contained QX-314 that antagonized the effect of veratridine in the recorded neuron, oscillatory membrane depolarization appeared in the early stage during bath-application of veratridine and gradually decreased in the late stage. After washout of veratridine, however, the oscillatory depolarization was gradually restored and maintained for at least 3 h. This oscillatory depolarization was also abolished by D-APV. We suggest that the activation of NMDA receptors is involved in the veratridine-induced long-lasting enhancement in the excitatory synaptic transmission in rat CA3 hippocampal neurons.

Correlation of early CT signs in the deep middle cerebral artery territories with angiographically confirmed site of arterial occlusion

BACKGROUND AND PURPOSE

Early CT signs in the deep middle cerebral artery (MCA) territories have been reported to be seen at the initial period of ischemia. We attempted to investigate the incidence of parenchymal hypodensity within 3 hours after ischemic onset among patients with angiographically proved embolic MCA occlusion and to assess the correlation of subtle hypodensity in the deep MCA territories with involvement of the lenticulostriate arteries in the presence of ischemia.

METHODS

Fifty CT images obtained within 3 hours after onset of embolic MCA occlusion were retrospectively reviewed by three neurosurgeons who were aware of clinical features. Early CT signs in the deep MCA territories were divided into three grades according to their anatomic location: grade I, normal basal ganglia with hypodensity localized to the insula; grade II, partial obscuration of the posterolateral part of the putamen; and grade III, hypodensity of the entire lentiform nucleus. A grade I CT sign was considered to be a negative finding for lenticulostriate artery involvement, whereas grade II and III CT signs were considered to be positive findings. Site of occlusion and involvement of the lenticulostriate arteries were confirmed by angiography.

RESULTS

Thirty-eight (76%) of 50 patients had early CT signs in the deep MCA territories. Sensitivity and specificity of a grade I CT sign indicating absence of lenticulostriate artery involvement in ischemia were 65% and 87%, respectively. On the other hand, sensitivity and specificity of grade II and grade III CT signs for presence of lenticulostriate artery involvement in ischemia were 77% and 100%, respectively. Grade II CT signs resulted from various sites of occlusion, whereas grade III was unequivocally predictive of proximal occlusion to all of the lenticulostriate arteries.

CONCLUSION

Involvement of the lenticulostriate arteries may be presumed by precise evaluation of subtle, CT-revealed hypodensity in the deep MCA territories, even within 3 hours of ischemic onset.

Delayed expression of calbindin D28k during regeneration of the periodontal Ruffini endings of the rat incisor following injury to the inferior alveolar nerve

Expression of calbindin D28k (CB)-like immunoreactivity (-LI) was compared with that of protein gene product 9.5 (PGP 9.5), a general neuronal marker, in the periodontal ligament of the rat lower incisor following resection of the inferior alveolar nerve (IAN). In normal animals, the periodontal nerve fibers showing PGP 9.5-LI formed either Ruffini endings with expanded arborization or thin free nerve endings in the alveolar half of the ligament. Thick CB-like immunoreactive (-IR) nerve fibers terminated in a dendritic fashion in the same region, but thin CB-IR nerve fibers were rarely detected. During the 3 days following resection of the IAN, most of the PGP 9.5-IR and all CB-IR nerve fibers disappeared. Regenerated PGP 9.5-IR nerve fibers appeared around 7 days after resection, in contrast to the very small number of regenerated CB-IR nerve fibers. Around 21-28 days following resection, the number and terminal morphology of regenerated PGP 9.5-IR nerve fibers were comparable to those observed in normal animals, but the number of regenerated CB-IR nerve fibers was still smaller. The terminal morphologies of these regenerated CB-IR nerve fibers showed less expansion compared with normal animals at these post-injured periods. The number of regenerated CB-IR nerve fibers increased gradually to return to normal by 56 days following injury. The delayed expression of CB in the regenerated periodontal Ruffini endings suggests that the functional recovery of periodontal Ruffini endings occurred after the regeneration of periodontal Ruffini endings had been completed.

Simultaneous up-regulation of urokinase-type plasminogen activator (uPA) and uPA receptor by hepatocyte growth factor/scatter factor in human glioma cells

Several lines of evidence indicate that hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, c-Met, may play an important role in progression of human glioma. In this study, effects of HGF/SF on urokinase- type plasminogen activator (uPA)-mediated proteolysis network were examined in c-Met-positive human glioma cell lines. Treatment of the glioma cells with various concentrations of HGF/SF resulted in an enhanced secretion of uPA proteins accompanying increased transcription of uPA mRNA in a dose dependent fashion. The levels of uPA receptor (uPAR) mRNAs were also elevated simultaneously upon HGF/SF stimulation, and the cell-surface associated uPA activity was also elevated by the treatment. Since concomitant expression of HGF and its receptor c-Met are frequently observed in malignant gliomas, these results suggest that HGF/SF participates in invasive process of malignant glioma cells not only by its motility-stimulating activity but also through enhanced degradation of the extracellular matrix induced by autocrine activation of uPA proteolysis network.

Poststenotic signal attenuation on 3D phase-contrast MR angiography: a useful finding in haemodynamically significant carotid artery stenosis

We performed blinded visual evaluation of MR angiography (MRA) films in 44 patients with unilateral carotid artery stenosis to determine whether a flow gap and poststenotic signal attenuation on 3D-PC MRA were useful signs of severe carotid artery stenosis. Although nine patients with a flow gap alone had various degrees of stenosis ranging from 22.2 to 77.3% without any decrease in regional cerebral blood flow (rCBF), 13 patients with both a flow gap and poststenotic signal attenuation had severe stenoses of 80% or more, with a definite decrease in baseline rCBF. The presence of both a flow gap and poststenotic signal attenuation on 3D-PC MRA appeared to be a reliable marker of severe carotid artery stenosis with a decrease in rCBF.

Reversibility of Ischemia Evaluated by Ischemic Duration and Residual Cerebral Blood Flow

We first investigated the time course of CBF thresholds of ischemic cortices by a retrospective review of 19 patients with MCA occlusion who had clearly defined ischemic duration from onset to angiographic complete recanalization. Secondly, CBF thresholds of ischemic cortices salvageable with intravenous low dose native t-PA infusion therapy (7.2 mg of tisokinase) were examined by a retrospective review of 20 patients with distal embolic occlusions of MCA divisions or branches. All patients underwent pretreatment CBF measurement by SPECT using 99mTc-ECD. Pretreatment SPECT and 3 months post-treatment CT images were compared using computerized coregistration. The degree of hypoperfusion was analyzed by an asymmetry index (AI), which was a count-density ratio for the ischemic lesion to the contralateral corresponding area. Ischemic cortices on SPECT were divided into reversible and irreversible lesions.

Judging from the regression lines with 95% confidence interval between the ischemic duration and AI, the infarcted CBF thresholds at 3 and 6 hours after onset may be about 30 and 50% of contralateral presumed normal CBF, respectively.

On the other hand, to save the ischemic tissue with our intravenous t-PA infusion therapy, residual CBF might be needed at least 45% of contralateral presumed normal CBF. It is likely that CBF threshold of ischemia surely salvageable with our intravenous t-PA infusion therapy may be approximately 50–55% of contralateral presumed normal CBF.

Expression of emmprin (CD147), a cell surface inducer of matrix metalloproteinases, in normal human brain and gliomas

EMMPRIN (extracellular matrix metalloproteinase inducer), also called CD147, basigin or M6 in the human, is a member of the immunoglobulin superfamily that is present on the surface of tumor cells and stimulates adjacent fibroblasts to produce matrix metalloproteinases (MMPs). In our study, we investigated expression of EMMPRIN in human normal brain and gliomas, since mouse basigin and chicken HT7, the species homologues of human EMMPRIN, are associated with neuronal interactions and normal blood-brain barrier function, respectively. EMMPRIN expression was detected in all samples of non-neoplastic brain and glioma tissues examined. However, expression levels of EMMPRIN mRNA and protein were significantly higher in gliomas than in non-neoplastic brain. Moreover, levels of mRNA expression and immunohistochemical staining correlated with tumor progression in gliomas: They were highest in the most malignant form of glioma, glioblastoma multiforme, followed by anaplastic astrocytoma and then low-grade astrocytoma. Also, immunolocalization revealed quite different distributions in non-neoplastic brain and glioma: EMMPRIN was demonstrated only in vascular endothelium in non-neoplastic regions of the brain, whereas it was present in tumor cells but not in proliferating blood vessels in malignant gliomas. These data indicate that an MMP inducer molecule EMMPRIN is differently expressed in human normal brain and gliomas and could be associated with astrocytoma progression. Possible mechanisms whereby glioma cell EMMPRIN could influence tumor progression will be discussed.

Radiographic and scintigraphic courses of union in cervical interbody fusion: hydroxyapatite grafts versus iliac bone autografts

This study investigated the radiographic and scintigraphic courses of union in cervical interbody fusion using hydroxyapatite (HA) grafts or iliac bone autografts.

METHODS

Twelve patients underwent both serial plain radiography and bone scintigraphy during the 12 mo after surgery. Serial plain radiographs were obtained every month until the end of the study period. Bone scintigrams with 99mTc-hydroxymethylene diphosphonate (HMDP) were obtained at 2 wk and at 1, 2, 3, and 6 mo. Uptake of 99mTc-HMDP in the graft was expressed as a ratio of the counts in the graft to those in the axis.

RESULTS

In the HA graft group, the plain radiographs of all patients showed a radiolucent stripe that disappeared 7.3 +/- 1.5 (mean +/- SD) months after surgery. In the autograft group, a radiolucent stripe around the graft was not seen for any patient, and union was confirmed by follow-up radiographs within 6 mo after surgery. The serial changes in the 99mTc-HMDP uptake ratio showed no difference between the 2 groups. The 99mTc-HMDP uptake ratio peaked 1 mo after surgery and decreased rapidly to a plateau within 2 mo.

CONCLUSION

In the HA graft group, despite the presence of a radiolucent stripe around the graft for more than 6 mo, the scintigraphic course of union was not different from that in the autograft group. The likelihood is that the presence of a radiolucent stripe around the HA graft in the early months after surgery is not always a sign of pseudoarthrosis.

Transient expression of heat shock protein (Hsp)25 in the dental pulp and enamel organ during odontogenesis in the rat incisor

The expression of heat shock protein (Hsp) 25 during odontogenesis in the dental pulp and enamel organ of rat incisors was investigated by immunocytochemistry and confocal microscopy. In the process of dentin formation, immature odontoblasts first exhibited Hsp 25-immunoreactivity, and increased in immunointensity with the advance of their differentiation. In the dental pulp, in contrast, intense immunoreaction in the mesenchymal cells became weak or negative in parallel with the progress of cell differentiation. The immunoreaction for Hsp 25 in the enamel organ revealed a characteristic stage-related alteration during amelogenesis. In secretory ameloblasts, the immunoreaction for Hsp 25 was found throughout their cell bodies, intense reactivity being located near the proximal and distal terminal webs. At the maturation stage, ruffle-ended ameloblasts (RA) consistently showed Hsp 25-immunoreactivity throughout the cell bodies, whereas smooth-ended ameloblasts (SA) lacking a ruffled border were weak in immunoreaction at the distal cytoplasm. Other cellular elements of the enamel organ were negative. The subcellular localization of Hsp 25-immunoreactivity in this study appeared essentially identical to that of actin filaments as demonstrated by confocal microscopy using rhodamine-labeled phalloidin. These immunocytochemical data suggest that the Hsp 25 molecule is involved in reinforcement of the cell layer following cell movement during odontogenesis and in the formation and maintenance of the ruffled border of RA.

Altered expression level of calbindin D28k in the periodontal ligament of rat molar in response to changes in occlusal force

The present immunohistochemical study was designed to investigate the alteration in the expression level of calbindin D28k in the periodontal ligament of the rat molar in response to changes in occlusal force to clarify the physiological role(s) of this protein in the ligament. In normal periodontal ligament of the lower first molar, immunoreactivity for calbindin D28k was found in the spindle-shaped cells, presumably fibroblasts, at the alveolar portion of the ligament at the distal side of the mesial root and mesial side of the distal root. Following the overload of occlusal force to the upper first molar by bite-raising, the number and immunoreactivity of the positive cells in the periodontal ligament of the lower first molar increased gradually. A more significant increase was detected at 7 d following the bite-raising compared to the normal animals. When occlusal force was removed by the extraction of the upper first molar, the expression level of calbindin D28k in the periodontal ligament of the lower first molar rapidly decreased, however a subsequent gradual increase was recognized. Statistical analysis of the spatial immunoreactivity of calbindin D28k in the periodontal ligament was performed and showed statistically significant differences. The present results suggest that calbindin D28k may play important roles in the homeostasis and cytoprotection of the periodontal fibroblasts against occlusal force.

Angiographic cerebral circulation time before and after endovascular therapy for symptomatic vasospasm

AIM

To investigate the correlation between angiographic cerebral circulation time (CCT) and cerebral blood flow (CBF) evaluated by single photon emission computed tomography (SPECT) before and after endovascular treatment for symptomatic vasospasm.

MATERIALS AND METHODS

Seven patients with unilateral vasospasm as demonstrated by catheter angiography who underwent pre- and post-treatment SPECT were selected. All patients had angiographic vasospasm of unilateral middle cerebral artery (MCA). Eight vessels in seven patients underwent intra-arterial papaverine infusion and three vessels underwent percutaneous transluminal angioplasty. Angiographic CCT was defined as the interval from the first image in which contrast medium was visible at the origin of MCA to its disappearance from the cortical arteries in the MCA territory. In SPECT studies, the ischaemic degree in MCA territory was analysed by side to side comparison with calculating the asymmetry index (AI).

RESULTS

The pre-treatment mean CCT was 4.1 +/- 0.8 s. The mean CCT immediately after treatment was 2.7 +/- 0.5 s. In the control subjects (n = 15) with unruptured aneurysm, mean CCT was 3.5 +/- 0.2 s. The pre-treatment mean CCT was significantly prolonged compared with that in the control subjects (P = 0.02). The post-treatment mean CCT was significantly shortened compared with that in the control subjects (P = 0.001). The pre-treatment mean AI was 71.2 +/- 7.4%, and that immediately after treatment was 90.5 +/- 3.6%. AI increased in all territories treated with endovascular treatment; the mean change was 19.3%. Angiographic CCT was closely correlated with AI in both pre- (r = - 0.95) and post-treatment (r = - 0.79).

CONCLUSION

Measurement of CCT is useful in evaluating cerebral haemodynamics of endovascular treatments in patients with cerebral vasospasm.

Glioma cell extracellular matrix metalloproteinase inducer (EMMPRIN) (CD147) stimulates production of membrane-type matrix metalloproteinases and activated gelatinase A in co-cultures with brain-derived fibroblasts

Extracellular matrix metalloproteinase inducer (EMMPRIN) also called CD147, basigin or M6 in the human is a member of the immunoglobulin superfamily that is enriched on the surface of tumor cells and stimulates adjacent stromal cells to produce several matrix metalloproteinases (MMPs). In this study, we have demonstrated that coculturing of EMMPRIN-expressing human glioblastoma multiforme cells (U251) with brain-derived human fibroblasts not only stimulates production, but also activation of pro-gelatinase A (proMMP-2), an enzyme that is enriched in malignant gliomas and most likely crucial to tumor progression. Production of membrane types 1 and 2-MMPs (MT1-MMP and MT2-MMP), which are activators of proMMP-2, was also stimulated in these cocultures. Stimulation of MMP-2, MT1-MMP and MT2-MMP production was inhibited by anti-EMMPRIN monoclonal antibody in a dose-dependent manner. Thus, we have shown, for the first time, that EMMPRIN causes increased expression of MT1-MMP and MT2-MMP, as well as increased production and activation of MMP-2.

Effects of neonatal injury of the inferior alveolar nerve on the development and regeneration of periodontal nerve fibers in the rat incisor

Our previous study showed that the migration of terminal Schwann cells occurred in the periodontal ligament of the rat lower incisor following transection of the inferior alveolar nerve (IAN) in the adult animals [Y. Atsumi, K. Matsumoto, M. Sakuda, T. Maeda, K. Kurisu, S. Wakisaka, Altered distribution of Schwann cells in the periodontal ligament of the rat incisor following resection of the inferior alveolar nerve: An immunohistochemical study on S-100 proteins, Brain Res. 849 (1999) 187-195]. The aim of the present study was to investigate the effects of neonatal transection of the IAN on the regeneration of axon elements and Schwann cells in the periodontal ligament of the rat lower incisor. Following transection of IAN at post-natal day 5 (PN 5d), when the numbers of both axon elements and the terminal Schwann cells were very small, regenerating nerve fibers appeared between post-injured days 7 (PO 7d) and PO 14d, and increased in number thereafter gradually. Although the terminal morphologies of regenerated Ruffini endings became identical to those of the adult animals by PO 54d, the number of regenerated PGP 9.5-IR nerve fibers did not recover the adult levels even by PO 56d. A small number of Schwann cells migrated into the shear zone, the border between the alveolus-related part (ARP) and the tooth-related part (TRP), but did not enter into the TRP. Following transection of the IAN at PN 14d or PN 28d, when clusters of apparent terminal Schwann cells could be recognized, axon regeneration started around PO 5d. Individual axon terminals of the regenerating Ruffini endings ramified and became identical to those of the adult animals around PO 28d, but the number of regenerated Ruffini endings was smaller than that of the adult animals. Similar to the adult animals, the migration of Schwann cells into the shear zone and TRP occurred, and disappeared prior to the completion of the axonal regeneration. The present results indicate that the migration of the Schwann cells into TRP during the regeneration of the periodontal nerve fibers following nerve injury to the IAN depends on the maturation of the terminal Schwann cells of the periodontal Ruffini endings, not on post-operative time.

Thresholds of ischemia salvageable with intravenous tissue plasminogen activator therapy: evaluation with cerebral blood flow single-photon emission computed tomographic measurements

OBJECTIVE

This study investigated the cerebral blood flow (CBF) thresholds of ischemic cortices that were salvageable with intravenous tissue plasminogen activator (t-PA) infusion therapy.

METHODS

We retrospectively reviewed data for 20 patients who were treated with intravenous low-dose (7.2 mg) native t-PA infusion therapy for distal embolic occlusions of middle cerebral artery divisions or branches, without early computed tomographic ischemic changes. All patients underwent pretreatment single-photon emission computed tomographic CBF measurements using (99m)Tc-N,N'-(1,2-ethylenediyl)bis-L-cysteine diethylester. Intravenous t-PA infusion was initiated within 6 hours (average, 3 h) after symptom onset for 14 patients and 6 to 14 hours (average, 8.8 h) after the last time the patient was noted to be in normal condition for the other 6 patients. Pretreatment single-photon emission computed tomographic and 3-month post-treatment computed tomographic scans were compared using computerized coregistration. Ischemic cortices in single-photon emission computed tomographic scans were divided into areas of reversible and irreversible ischemia. The degree of hypoperfusion was analyzed with an asymmetry index (AI). The AI was calculated as C(a)/C(b) x 100%, where C(a) represents the mean reconstructed counts for the ipsilateral ischemic area and C(b) represents the mean reconstructed counts for the corresponding contralateral area.

RESULTS

Partial recanalization, with clinical improvement, at 60 minutes was confirmed by angiography for 14 of the 20 patients (70%). Seventeen of the 20 patients (85%) exhibited major neurological improvements (defined as decreases in National Institutes of Health Stroke Scale scores of > or =4 points) at 24 hours, suggesting that recanalization occurred within 24 hours for almost all patients. AIs for the 25 irreversible lesions ranged from 15.0 to 53.4% (37.3 +/- 11.6%), whereas AIs for the 38 reversible lesions ranged from 45.0 to 83.1% (69.3 +/- 8.6%). There was a significant difference in the AIs for these two groups (P < 0.0001). The ischemia in tissue with AIs of more than 53.4% was reversible. In contrast, ischemic tissue with AIs of less than 45.0% could not escape cerebral infarction with our treatment. The ischemia in tissue with AIs between 45.0 and 53.4% was reversible in some patients and irreversible in others.

CONCLUSION

To save ischemic tissue with our intravenous t-PA infusion therapy, residual CBF should be at least 45% of the contralateral presumed normal CBF value. CBF thresholds for ischemia that would be surely salvageable with our intravenous t-PA infusion therapy might be approximately 50 to 55% of the contralateral presumed normal CBF values.

Parathyroid hormone-related peptide is involved in protection against invasion of tooth germs by bone via promoting the differentiation of osteoclasts during tooth development

In order to elucidate the role of parathyroid hormone-related peptide (PTHrP) in tooth development, we treated tooth germ explants of mouse molars with antisense phosphorothioate-oligodeoxynucleotide (ODN) against PTHrP. Antisense ODN-treatment of the explants resulted in the invasion of the tooth germs by bone. The number of tartrate-resistant acid phosphatase (TRAP)-positive cells around the tooth germs in antisense ODN-treated explants was much lower than that of the control explants. Electron microscopic examination suggested that the antisense ODN-treatment inhibited differentiation of osteoclasts. Treatment of the explants with bisphosphonate or vitamin K2, inhibitors of the differentiation of osteoclasts, induced the invasion by bone into the tooth germs as observed in the antisense ODN-treated explants. The results obtained suggest that PTHrP is involved in the mechanism protecting tooth germs from bone invasion by promoting the differentiation of osteoclasts around them.

Morphological and cytochemical characteristics of periodontal Ruffini ending under normal and regeneration processes

Current knowledge on the Ruffini endings, primary mechanoreceptors in the periodontal ligament is reviewed with special reference to their cytochemical features and regeneration process. Morphologically, they are characterized by extensive ramifications of expanded axonal terminals and an association with specialized Schwann cells, called lamellar or terminal Schwann cells, which are categorized, based on their histochemical properties, as non-myelin-forming Schwann cells. Following nerve injury, the periodontal Ruffini endings of the rat incisor ligament can regenerate more rapidly than Ruffini endings in other tissues. During regeneration, terminal Schwann cells associated with the periodontal Ruffini endings migrate into regions where they are never found under normal conditions. Also during regeneration, alterations in the expression level of various bioactive substances occur in both axonal and Schwann cell elements in the periodontal Ruffini endings. Neuropeptide Y, which is not detected in intact periodontal Ruffini endings, is transiently expressed in their regenerating axons. Growth-associated protein-43 (GAP-43) is expressed transiently in both axonal and Schwann cell elements during regeneration, while this protein is localized in the Schwann sheath of periodontal Ruffini endings under normal conditions. The expression of calbindin D28k and calretinin, both belonging to the buffering type of calcium-binding proteins, was delayed in periodontal Ruffini endings, compared to their morphological regeneration. As the importance of axon-Schwann cell interactions has been proposed, further investigations are needed to elucidate their molecular mechanism particularly the contribution of growth factors during the regeneration as well as development of the periodontal Ruffini endings.

The Ruffini ending as the primary mechanoreceptor in the periodontal ligament: its morphology, cytochemical features, regeneration, and development

The periodontal ligament receives a rich sensory nerve supply and contains many nociceptors and mechanoreceptors. Although its various kinds of mechanoreceptors have been reported in the past, only recently have studies revealed that the Ruffini endings--categorized as low-threshold, slowly adapting, type II mechanoreceptors--are the primary mechanoreceptors in the periodontal ligament. The periodontal Ruffini endings display dendritic ramifications with expanded terminal buttons and, furthermore, are ultrastructurally characterized by expanded axon terminals filled with many mitochondria and by an association with terminal or lamellar Schwann cells. The axon terminals of the periodontal Ruffini endings have finger-like projections called axonal spines or microspikes, which extend into the surrounding tissue to detect the deformation of collagen fibers. The functional basis of the periodontal Ruffini endings has been analyzed by histochemical techniques. Histochemically, the axon terminals are reactive for cytochrome oxidase activity, and the terminal Schwann cells have both non-specific cholinesterase and acid phosphatase activity. On the other hand, many investigations have suggested that the Ruffini endings have a high potential for neuroplasticity. For example, immunoreactivity for p75-NGFR (low-affinity nerve growth factor receptor) and GAP-43 (growth-associated protein-43), both of which play important roles in nerve regeneration/development processes, have been reported in the periodontal Ruffini endings, even in adult animals (though these proteins are usually repressed or down-regulated in mature neurons). Furthermore, in experimental studies on nerve injury to the inferior alveolar nerve, the degeneration of Ruffini endings takes place immediately after nerve injury, with regeneration beginning from 3 to 5 days later, and the distribution and terminal morphology returning to almost normal at around 14 days. During regeneration, some regenerating Ruffini endings expressed neuropeptide Y, which is rarely observed in normal animals. On the other hand, the periodontal Ruffini endings show stage-specific configurations which are closely related to tooth eruption and the addition of occlusal forces to the tooth during postnatal development, suggesting that mechanical stimuli due to tooth eruption and occlusion are a prerequisite for the differentiation and maturation of the periodontal Ruffini endings. Further investigations are needed to clarify the involvement of growth factors in the molecular mechanisms of the development and regeneration processes of the Ruffini endings.

Intravenous low-dose native tissue plasminogen activator for distal embolism in the middle cerebral artery divisions or branches: a pilot study

OBJECTIVE

We prospectively evaluated the safety and efficacy of an intravenous infusion of low-dose native tissue plasminogen activator for distal embolisms in the middle cerebral artery divisions or branches.

METHODS

Twenty patients were selected according to the following computed tomographic and angiographic criteria and treated with intravenous infusion of 7.2 mg of tisokinase: 1) no early ischemic changes on the initial computed tomographic scan, and 2) embolic occlusion of the middle cerebral artery divisions or branches without the involvement of the lenticulostriate arteries. For comparison, the records of 12 patients from previous years who met the above inclusion criteria but underwent no thrombolytic therapy were reviewed retrospectively. The degree of neurological recovery was assessed using the National Institutes of Health Stroke Scale at 24 hours after admission. Major neurological improvement was defined as a decrease in the stroke score by 4 points or more.

RESULTS

There was no significant difference in stroke scores at the time of admission between the treatment group (mean +/- standard deviation, 12.8 +/- 2.8) and the untreated group (14.0 +/- 2.4). In the treatment group, major neurological improvement was seen in 17 (85%) of 20 patients, whereas in the untreated group only 5 (41.7%) of 12 patients showed major neurological improvement (P < 0.05). The mean score at 24 hours in the treatment group (3.6 +/- 3.5) was significantly lower than that in the untreated group (9.4 +/- 7.3) (P < 0.05). There was no hemorrhagic complication with neurological exacerbation in the treatment group.

CONCLUSION

Even with delayed initiation (>3 h after symptom onset), intravenous infusion of low-dose tisokinase may be safe and effective for small distal emboli in the middle cerebral artery divisions or branches, when early ischemic changes on computed tomographic scans and involvement of the lenticulostriate arteries are absent.

Unilateral middle cerebral artery stenosis in an adult with Down's syndrome--case report

A 29-year-old male with Down's syndrome presented with severe headache and vomiting. Computed tomography demonstrated subarachnoid hemorrhage. Left carotid angiography showed severe stenosis of the middle cerebral artery 2 cm distal to its origin, as well as abnormal hyper-vascularization near the stenosis site similar to that seen in moyamoya disease. Right carotid angiography showed no abnormalities. However, slight stenosis of the distal part of the bilateral vertebral arteries was noted. There was no aneurysm. We judged that the subarachnoid hemorrhage had been caused by rupture of the moyamoya-like vessel. Some patients with Down's syndrome have anatomical vascular abnormality and vascular fragility. The cerebral vascular abnormality found in this case may be part of the systemic vascular abnormalities associated with Down's syndrome. The vascular changes in some adult patients with Down's syndrome may be a sign of premature aging, and long-term studies with periodic vascular examination of patients with Down's syndrome need to be performed.

Calbindin D28k-like immunoreactivity during the formation of the enamel-free area in the rat molar teeth

Previous studies have demonstrated the presence of calbindin D28k in the ameloblasts derived from the inner enamel epithelium. The occlusal surfaces of the rodent molars partly lack the enamel covering, which is referred to as enamel-free area (EFA). In the present study, we compared the immunohistochemical localization of calbindin D28k-like immunoreactivity (CB-LI) in the cells at the EFA (EFA cells) and ameloblasts of the rat molar teeth at the light microscopic level. CB-LI was strong in the ameloblasts of the presecretory through the protective stages, while it was faint at the late secretory to transitional stages. However, some mature ameloblasts lacked the immunoreactivity. On the other hand, the majority of EFA cells showed distinct polarization and elongation that were absent in few cells at the early stage of EFA formation. At all stages, the EFA cells adjacent to the ameloblasts showed CB-LI, however, some cells adjacent to the mature ameloblasts lacked the reaction. Intensive CB-LI was demonstrated in EFA cells at the reduced enamel epithelium. These immunohistochemical findings suggest EFA cells have cytochemical properties similar to those of ameloblasts.

A combination of wrapping and clipping using a collagen-impregnated dacron fabric (Hemashield)

BACKGROUND

We describe techniques combining wrapping and clipping using a collagen-impregnated Dacron knitted fabric (Hemashield) for accidental arterial perforations and broad-based aneurysms. The results of these techniques in seven patients are presented.

METHODS

Clip-reinforced wrapping was performed to obtain hemostasis in two patients with arterial perforations and in a patient with a ruptured broad-based aneurysm in the internal carotid artery. Clipping of the broad neck of the aneurysm and wrapping with Hemashield (wrap-clipping) was performed in four patients with unruptured aneurysms (one internal carotid artery, two middle cerebral artery, one basilar artery).

RESULTS

In the three patients treated with clip-reinforced wrapping, complete hemostasis was obtained just after clip application. In the patient with a ruptured broad-based aneurysm, postoperative angiography demonstrated that the dome of the aneurysm was well compressed. In the four patients treated with wrap-clipping, postoperative angiography revealed successful clipping of the broad neck of the aneurysm.

CONCLUSION

In this early experience, there were no problems in the use of Hemashield for clip-reinforced wrapping or wrap-clipping.

The development of terminal Schwann cells associated with periodontal Ruffini endings in the rat incisor ligament

The postnatal development of the terminal Schwann cell, an analogue of the lamellar cell in cutaneous sensory receptors, was examined by histochemistry for non-specific cholinesterase and immunohistochemistry for S-100 protein in the periodontal Ruffini endings of the rat incisor. Double immunohistochemistry for S-100 protein and protein gene product 9.5 (PGP 9.5) was also performed to examine the relationship between terminal Schwann cells and axons. Histochemistry for non-specific cholinesterase was able to demonstrate the age-related development of the terminal Schwann cells; the morphology and distribution of the developing terminal Schwann cells became almost identical to those in adults during postnatal days 15-18. Axons showing PGP 9.5-like immunoreactivity elongated and expanded after arrangement of terminal Schwann cells in the alveolus-related part. This suggests that the terminal Schwann cell is important in the development and maturation of the periodontal Ruffini endings.

Effects of different types of injury to the inferior alveolar nerve on the behavior of Schwann cells during the regeneration of periodontal nerve fibers of rat incisor

The present study reports on different regeneration patterns of axons and Schwann cells in the periodontal ligament of the rat incisor using immunohistochemistry of protein gene product 9.5 (PGP 9.5) and S-100 protein. Three kinds of injury (transection, crush and segmental resection) were applied to the inferior alveolar nerve. In normal animals, PGP 9.5- and S-100-immunoreactivities were detected in the axons and Schwann cell elements of periodontal Ruffini endings, respectively. They were restricted to the alveolus-related part, occurring only rarely in the tooth-related part and in the shear zone (the border between the alveolus-related and tooth-related parts). Both transection and segmental resection caused the complete disappearance of PGP 9.5-immunoreactive nerve fibers in the periodontal ligament, while a small number of them could be found following the crush injury. Regenerating PGP 9.5-reactive nerve fibers appeared at 5 days and 21 days following the transection and segmental resection, respectively. The regeneration of periodontal nerve fibers completed in a period of 21-28 days and 14-21 days following the transection and crush, respectively, but was not completed even at 56 days following the segmental resection. The behavior of Schwann cells during regeneration was similar after the different nerve injuries; spindle-shaped S-100-immunoreactive cells, presumably Schwann cells, appeared in the shear zone and the tooth-related part. These cells disappeared 5-7 days prior to the completion of the regeneration of axonal elements of the periodontal ligament following the transection and crush. Following the segmental resection, in contrast, spindle-shaped S-100-positive cells disappeared from the tooth-related part at 42 days, although the axonal regeneration of periodontal Ruffini endings proceeded even until 56 days. We thus conclude that the duration of the migration of Schwann cells depends on the state of the regeneration of axons.

Intrathecal lithium reduces neuropathic pain responses in a rat model of peripheral neuropathy

We tested the ability of lithium (Li(+)) to block heat hyperalgesia, cold allodynia, mechanical allodynia and mechanical hyperalgesia in rats experimentally subjected to painful peripheral neuropathy. Chronic constrictive injury (CCI) to the sciatic nerve induced persistent hyperalgesia and allodynia. Intrathecal injection of Li(+) (2.5-40 micromol) into the region of lumbar enlargement dose-dependently reduced heat hyperalgesia, cold allodynia and mechanical allodynia for 2-6 h after injection, but had no effect on mechanical hyperalgesia. Li(+) had no significant effect on responses from control and sham-operated animals. Intrathecal injection of myo-inositol (2.5 mg) significantly reversed both the anti-hyperalgesic and anti-allodynic effect of Li(+). These findings suggest that intrathecal Li(+) suppresses neuropathic pain response in CCI rats through the intracellular phosphatidylinositol (PI) second messenger system in spinal cord neurons. Lithium (Li(+)) has already found widespread clinical application; these results suggest that its therapeutic utility may be extended to include treatment of neuropathic pain syndromes resulting from peripheral nerve injury.

Immunohistochemical detection of heme oxygenase-2 in the periodontal Ruffini ending of the rat incisor

The present study was carried out to examine the occurrence of heme oxygenase-2 (HO-2) in the periodontal ligament of the rat incisor. HO-2-like immunoreactive (-IR) structures showed dendritic profiles, resembling the Ruffini endings, in the alveolar half of the ligament of rat incisor. Neither thin nerve fibers nor perivascular nerve fibers displayed HO-2-like immunoreactivity (-LI). No non-neural elements exhibited HO-2-LI. Electron microscopy revealed that immunoreactions were diffusely observed in the axon terminals of the Ruffini endings, but neither terminal Schwann cells nor Schwann sheaths contained immunoreactions for HO-2. Both most neurons in the trigeminal ganglion and trigeminal mesencephalic nucleus showed HO-2-LI. The presence of HO-2 in the periodontal Ruffini endings and its absence in the periodontal thin nerve fibers suggest the involvement of carbon monoxide produced by HO-2 in mechanoreception in the periodontal ligament.

Oral findings in DiGeorge syndrome: clinical features and histologic study of primary teeth

OBJECTIVE

For the purpose of supplementing the shortage of dental information about DiGeorge syndrome, we report two cases of the syndrome seen in Japanese boys.

STUDY DESIGN

Two cases were compared with respect to orofacial and dental findings; one was a case of complete DiGeorge syndrome and the other a case of partial DiGeorge syndrome. Extracted deciduous teeth from the two boys underwent histologic study.

RESULTS

Each patient showed systemic developmental delay, hypocalcemia, and slight mental retardation. In the orofacial area, hypertelorism, a short philtrum, thick and reflected lips, and hypoplasia of the nasopharynx were also observed. A dental examination showed delayed formation and eruption of permanent teeth, aplasia of the nasopharynx, and enamel hypoplasia along with enamel hypocalcification. Structural streaks with increased calcification were histologically detected in the deciduous tooth from the patient with complete DiGeorge syndrome.

CONCLUSIONS

Common characteristic orofacial and dental findings were noted in the two DiGeorge syndrome cases. Furthermore, histologic study of the deciduous tooth from the boy with complete DiGeorge syndrome suggests that there was some relationship between transient relative hypercalcemia and dentinal hypermineralized streaking of the tooth.

Serine phosphorylation and maximal activation of STAT3 during CNTF signaling is mediated by the rapamycin target mTOR

Neuropoletic cytokines such as ciliary neurotrophic factor (CNTF) can activate multiple signaling pathways in parallel, including those involving Janus kinase (JAK)-signal transducers and activators of transcription (STATs), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI 3-kinase) and mammalian target of rapamydn (mTOR)-p70 S6 kinase . Crosstalk occurs between these pathways, because studies have shown that STAT3 requires phosphorylation on tyrosine and serine residues by independent protein kinase activities for maximal activation of target gene transcription. Members of the JAK/Tyk family of tyrosine kinases mediate phosphorylation of STAT3 at Tyr705 during CNTF signaling; however, the kinase responsible for phosphorylation at STAT3 Tyr727 appears to depend on both the extracellular stimulus and the cellular context. Here we investigate the kinase activity responsible for phosphorylation of STAT3 on Ser727 in CNTF-stimulated neuroblastoma cells. We found that CNTF-induced phosphorylation of Ser727 was inhibited by the mTOR inhibitor rapamycin, but not by inhibitors of MAPK and protein kinase C (PKC) activation. A STAT3 peptide was efficiently phosphorylated on Ser727 in a CNTF-dependent manner by mTOR, but not by a kinase-inactive mTOR mutant or by p70 S6 kinase. In agreement with these biochemical studies, rapamycin treatment of cells transfected with a STAT-responsive promoter reporter decreased activation of the reporter to the same degree as a STAT3 Ser727Ala mutant The ability of mTOR to contribute to activation of STAT3 extends the function of mTOR in mammalian cells to include transcriptional regulation.

Involvement of cAMP responsive element binding protein (CREB) in the synovial cell hyperfunction in patients with rheumatoid arthritis

OBJECTIVE

To elucidate a possible role of cAMP responsive element binding protein (CREB) in rheumatoid arthritis (RA) synovial cell function, we have studied CREB expression of synovial cells and the effects of an inhibitor of the cAMP/CREB signal pathway on synovial cell function in patients with RA.

METHODS

We examined CREB expression by immunohistochemical staining, immunocytochemical staining, and gel shift assays. Effects of cAMP/CREB inhibitor on the proliferation of RA synovial cells were assessed by [3H]-TdR incorporation, and those on proinflammatory cytokine and matrix metalloproteinase (MMP) production by reverse transcription PCR and ELISAs.

RESULTS

Immunohistochemical staining of synovial tissue revealed that CREB is expressed mainly in the lining and sublining layers of synovium in patients with RA. DNA binding activity of CREB was ascertained by a gel shift assay. We also confirmed nuclear translocation and phosphorylation of CREB in TNF-alpha stimulated RA fibroblast-like synovial cells by immunocytochemical staining. Modulators of cAMP/CREB signaling pathway, such as Rp-cAMP, had an inhibitory potential on RA synovial cell proliferation in vitro. Rp-cAMP also inhibited the proinflammatory cytokine and MMP production.

CONCLUSION

CREB is involved in the synovial cell activity in patients with RA. Inhibition of CREB activity by its inhibitor brings about the correction of aberrant synovial cell functions in patients with RA, thus suggesting a possible clinical application of cAMP/CREB inhibitors.