Calcitonin gene-related peptide acts as a mitogen for human Gin-1 gingival fibroblasts by activating the MAP kinase signalling pathway

In many peripheral tissues, calcitonin gene-related peptide (CGRP) is released from peptidergic sensory nerve fibres and acts like a growth factor during tissue development and regeneration. However, the ability of CGRP to influence gingival tissue has not been studied. To address this question, we have now examined the effects of CGRP on the proliferation of human gingival fibroblasts (Gin-1) in vitro. Gin-1 cells have approximately 3100 specific CGRP-binding sites with a Kd of 38.6 pM on their surface. Treatment with CGRP (0.1-100 nM) significantly stimulated cell proliferation in a dose-dependent manner, with maximal effects at 1-10 nM CGRP after 2 d. As one early cellular response to CGRP, p44-MAPK protein (also known as the extracellular signal response kinase [ERK]) was tyrosine- and threonine-phosphorylated within 2 min, and this phosphorylation was sustained for at least 1 h. The dose-response curve of MAPK activation was very similar to that observed for CGRP's stimulation of cell proliferation. In addition, CGRP's activation of MAPK stimulated its ability to phosphorylate the Elk-1 transcription factor. When cells were pretreated with PD98059, a selective inhibitor of MAPK kinase (also known as MEK), CGRP not only failed to induce phosphorylation of MAPK but also failed to stimulate Gin-1 cell proliferation. Our present data indicate that CGRP rapidly activates the MAPK signalling pathway, an effect which consequently stimulates the proliferation of gingival fibroblasts. Our data demonstrate specific cellular responses to CGRP by gingival fibroblasts and support the possibility that CGRP acts as a targeted local factor in the regulation of development, generation and/or regeneration of gingival tissues.

Endoscopic variceal ligation is a sufficient procedure for the treatment of oesophageal varices in patients with hepatitis C liver cirrhosis: comparison with injection sclerotherapy

AIMS

Endoscopic variceal ligation (EVL) is a recently developed alternative to endoscopic injection sclerotherapy (EIS) for the treatment of oesophageal varices. Endoscopic variceal ligation and EIS were compared in an attempt to clarify the efficacy and safety of EVL for patients with cirrhosis due to hepatitis C.

METHODS

Endoscopic variceal ligation was performed in 60 patients and EIS in 30. Varices were eradicated in all patients by EVL and 87% (26 out of 30) by EIS.

RESULTS

There was no significant difference between EVL and EIS in relation to the incidence of bleeding and the 5 year survival rate after treatment. There were no severe complications except mild substernal pain after EVL, while pulmonary embolism occurred in one patient receiving EIS.

CONCLUSIONS

Endoscopic variceal ligation is a safe and effective technique for eradicating oesophageal varices in patients with hepatitis C cirrhosis.

Sound localization for a virtual sound source in cases of chronic otitis media

Sound localization in subjects with chronic otitis media (COM) was examined before and soon after ear surgery by means of virtual sound presented by headphones, sound being synthesized based on the head-related transfer functions (HRTFs) in a normal subject. The localization ability in COM patients was usually worse than that in normal subjects, but was better than expected when compared with cases of acute loss. On the other hand, the effects of hearing improvement on localization ability observed in COM patients were smaller than those of simulated acute hearing loss achieved by earplugs in normal subjects. This seems to suggest that the localization cues in patients with chronic hearing loss are different from those under normal conditions.

Transcranial magnetic stimulation of the central and peripheral motor pathways to the lingual muscles in cats

OBJECTIVE

We have assessed a technique to stimulate the intracranial hypoglossal nerve with ease and reproducibility by using magnetic coils (MCs) and to detect a reliable site of excitation in animal experiments in order to establish a method to evaluate the motor pathway to lingual muscles.

METHODS

We recorded the motor responses from the lingual muscles of 5 adult cats under general anesthesia by magnetic and electrical stimulation of the intracranial hypoglossal nerves. Figure of 8 and round MCs were used to investigate the optimal position and direction to evoke the motor responses.

RESULTS

The round MC was useful for cortical stimulation. The figure of 8 coil, positioned in the back of the head of the examined side, parallel to the cervical spine, was essential for stimulation of the intracranial hypoglossal nerve. Analysis of the latencies, and the observation that the motor responses disappeared after transection of the nerves at the exit of the hypoglossal canal, demonstrated that the site of the excitation is at the exit of the hypoglossal canal.

CONCLUSION

Magnetic stimulation using a figure of 8 coil can elicit tongue motor responses with ease and reliable reproducibility, stimulating the hypoglossal nerve at the exit of the hypoglossal canal.

[A case of enlarged infundibular dilatation diagnosed by vertebral angiograms with carotid compression and neuroendoscope]

A case of enlarged infundibular dilatation diagnosed by vertebral angiograms with carotid compression was reported. A 57-year-old woman suffered from headache. She underwent MRA which revealed left internal carotid artery aneurysm. Left common carotid angiograms suggested a left saccular internal carotid artery aneurysm (4 mm x 6 mm) without a posterior communicating artery. However, it was confirmed to be an enlarged infundibular dilatation on left vertebral angiograms with carotid compression. It was confirmed at operation microscopically and neuroendoscopically, and the dilatation was treated by coating. When carotid angiograms reveal no posterior communicating artery, it is difficult to differentiate the origin of posterior communicating artery from internal carotid artery-posterior communicating artery junction aneurysms. Vertebral angiograms with carotid compression is useful for the differentiation for the exact diagnosis.

Possible regulation of epidermal growth factor-receptor tyrosine autophosphorylation by calcium and G proteins in chemically permeabilized rat UMR106 cells

A model using chemically permeabilized cells was developed to examine mechanisms that regulate protein tyrosine phosphorylation in osteoblastic cells. Using either permeabilized UMR106 osteoblastic or A431 (reference) cells, epidermal growth factor (EGF)-induced cellular tyrosine phosphorylation, and whether there are previously unrecognized interactions between this transduction pathway and Ca2+- or G protein-dependent signalling pathways, were investigated. Both permeabilized cell types, when maintained in non-supplemented cytoplasmic substitution solution (basic CSS), responded to EGF (1-100 ng/ml) with dose-dependent increases in tyrosine phosphorylation. A complex and time-dependent pattern of phosphotyrosine-containing proteins resulted, but the profile of tyrosine phosphorylated proteins was appreciably less complex than in intact cells. Supplementation of basic CSS with MgATP restored the normal complexity of the profiles for EGF-induced tyrosine phosphorylation proteins in both permeabilized cell lines and produced a more sustained accumulation of phosphoprotein products in A431 cells. Adding Ca2+ (< or = 10(-6) M), with or without exogenous MgATP, dose-dependently attenuated EGF-induced tyrosine phosphorylation of EGF receptors (EGFR) and other substrates in UMR106 cells, but was less effective in A431 cells. In both cell types, genistein, an inhibitor of tyrosine kinases, was more effective in attenuating EGF-induced receptor tyrosine phosphorylation in permeabilized cells. Similarly, orthovanadate, an inhibitor of protein tyrosine phosphatases, stimulated the accumulation of phosphoprotein products more effectively in permeabilized cells. Thus, the permeabilization preserves many features of intact cells while facilitating manipulation of intracellular conditions. NaF reproducibly produced a significant vanadate-like action in permeabilized cells that was somewhat stronger than its effect on intact cells. In contrast, the well-known inhibition of tyrosine phosphorylation by phorbol 12-myristate 13-acetate (PMA) was less effective in permeabilized cells than in intact cells; these actions of PMA were Ca2+-dependent. In addition, guanylyl-imidodiphosphate (Gpp(NH)p) attenuated tyrosine phosphorylation in UMR106 cells, and this effect was specifically blocked by guanosine 5'-O-(2-thiodiphosphate) (GDPbetas). These results strongly suggest that there is crosstalk between EGFR-activated tyrosine phosphorylation/dephosphorylation pathways and both Ca2+- and G protein-mediated pathways in UMR106 cells, revealing a previously unrecognized modulation of EGF signalling in osteoblast-like cells that contrasts with the simpler regulatory mechanisms found in A431 cells.

Suppression of glial tumor growth by expression of glial fibrillary acidic protein

We examined the effect of expression of glial fibrillary acidic protein (GFAP) on the tumor growth of astrocytoma in vivo. When rat astrocytoma C6 cells were injected subcutaneously in athymic mice, the cells produced tumors that grew rapidly. The tumor growth of C6 cells transfected with GFAP cDNA was significantly reduced compared to that of control NeoC6 cells transfected only with the neomycin resistant gene. After implantation of C6 cells transfected with mutated GFAP cDNA at the phosphorylation sites, the tumor growth was suppressed similar to that of the wild GFAP transfectants. To determine whether the cell growth suppression by GFAP is specific for astroglial cells, we assessed the effect of GFAP on the cell growth of an L cell of fibroblast origin in vitro. By GFAP cDNA transfection, L cells showed morphological changes, but the cell growth was not reduced. These results suggest that GFAP is a critical regulator of the tumor growth of astrocytoma.

[The use of computers and networking in the neurosurgical field]

Due to the improvements in computer and network technology, we are able to use medical information easily and safely on the network in medical institutions. In our department, we constructed and used an original Intranet with light fibers. The network links the outpatient room, ward, operation room, staff room and the examination room. Moreover, many computers and medical instruments are connected to the Intranet. Since our original Intranet has no connection with the outside network, we are able to access the patient's medical information safely. Using access management of identity and a password on the server, the client can present the medical information with sound and movie upon request of the patients and their families, medical students, nurses and doctors. Doctors can also search and input the patient's most recent medical information on a network database of every client. By linking the examination machine and operation aided instrument to the Intranet, we were able to forward the patient's medical information to the operation aided instrument easily and quickly. Furthermore, we will be able to perform tele-medicine and tele-operation in the near future: that is, the medical staff can guide the neurosurgical operation outside of the operation room with a microscope and computer view using picture mutual communication devices. By strict access to the management of our Intranet, we are able to use the medical information effectively for patient's treatment, operation, education and study on the network with no connection to the outside network.

Neuropsychological evaluation and cerebral blood flow study of 30 patients with unruptured cerebral aneurysms before and after surgery

BACKGROUND

We have recently had many opportunities to operate on patients who presented with no neurologic deficits and were incidentally detected to have unruptured cerebral aneurysms. Therefore, it is very important to know how craniotomy affects the normal brain when making decisions regarding surgery for asymptomatic cerebral diseases.

METHODS

Thirty patients with unruptured cerebral aneurysms were evaluated. Aneurysm sites were as follows: internal carotid artery (ICA) (eight cases), anterior communicating artery (ACoA) (seven), middle cerebral artery (MCA) (five), basilar artery-superior cerebellar artery (BA-SCA) (two), and multiple aneurysms (three) [bilateral MCA: (two), ICA + Basilar top: (one)]. These patients underwent neuropsychological examinations [the Mini-Mental State (MMS) test, the "Kana-hiroi" test, and the "Maze" test] and single photon emission computed tomography (SPECT) before and after surgery.

RESULTS

The details of the 17 cases whose Kana-hiroi tests deteriorated 1 month after surgery are as follows: ACoA: seven, MCA: five, ICA: three, BA: two. SPECT showed a decrease in CBF in nine cases (ACoA: six, ICA: two, MCA: one). There was a statistically significant difference (p<0.05) between patients with ACoA aneurysms and ICA aneurysms. Three months after operation, all of the patients with neuropsychological deterioration and four of the six low CBF patients recovered to preoperative levels.

CONCLUSIONS

These results indicated that the operation for unruptured cerebral aneurysms is moderately safe and meaningful; such a study should be required to determine when those patients could return to normal life.

In vivo rat closed spinal window for spinal microcirculation: observation of pial vessels, leukocyte adhesion, and red blood cell velocity

OBJECTIVES

An in vivo closed spinal window technique in rats was designed for observing the spinal microcirculation, such as the change of vessel diameter, leukocyte adhesion, and red blood cell (RBC) velocity, which has been very rarely examined in vivo in the spinal cord.

METHODS

We made a very precise closed spinal window with a laminectomy at the C5 level using a dental acrylic resin and a cover glass (7 mm in diameter). Through this closed window, the dorsal surface of the rat cervical cord was observed with a video microscope, and the fluorescent images of rhodamine 6G-labeled leukocytes and fluorescein isothiocyanate-labeled RBCs were recorded and analyzed with a silicon-intensified target tube camera (30 frames/s) and an image-intensified high-speed video camera system (1000 frames/s).

RESULTS

During CO2 inhalation, the pial arterioles responded with vasodilation of 12.4+/-10.4% (P<0.01) in 11 arterioles of seven rats. The adhering leukocytes significantly increased in 41 venular segments of seven rats after superfusion of the neutrophil chemoattractant, N-formyl-methionine-leucine-phenylalanine solution for 15 minutes (P<0.001) but not after superfusion of only artificial cerebrospinal fluid for 15 minutes. During these experiments, no adhering leukocyte was seen in the pial arterioles. Fluorescein isothiocyanate-labeled RBCs look like shooting stars in arterioles with silicon-intensified target tube camera processing at 30 frames per second, but individual fluorescein isothiocyanate-labeled RBCs could be recognized frame by frame with the image-intensified high-speed video camera system. In 13 arterioles of four rats, the RBC velocity was 5.3+/-2.0 mm per second.

CONCLUSION

This closed spinal window technique in rats is available and applicable for the study of the spinal microcirculation, such as the pathophysiology of a secondary injury.

Effect of hyperosmotic solutions on human brain tumour vasculature

Reversible opening of the blood-brain barrier (BBB) has been used to increase delivery of chemotherapeutic agents into brain tumours, but it is complicated and requires general anaesthesia. Without affecting the normal BBB, and avoiding the complications of BBB modification by hyperosmotic solution, we tried an adequate minimal BBB disruption in brain tumours. Although the effect of BBB disruption on normal brain has been described, there are no reports of the effect of an impaired BBB on microcirculation. In this study, four patients underwent surgical resection of a glioblastoma multiforme (GM; n = 1), astrocytoma (n = 2), or metastatic brain tumour (n = 1). Epicerebral microcirculation was observed in the operative field. Serial fluorescein microangiograms of the tumour and peritumoural area were obtained before and after BBB disruption was introduced intra-operatively by retrograde infusion of mannitol introducing a catheter via the temporal superficial artery back to the carotid bifurcation. On the initial microangiogram, staining by the fluorescein dye was observed in the GM and metastatic tumour but not in the astrocytoma; no extravasation of fluorescein dye was observed in the peritumoural areas. After BBB disruption, fluorescein perfusion increased and extravasation of fluorescein dye from the venules was observed in the GM and the metastatic tumour and in the peritumoural area of both lesions; BBB disruption started from venules in the peritumoural area without affecting the normal brain. However, such effects were not observed in the astrocytomas after BBB disruption nor in normal brain tissue in any patient. It appears that the integrity of the BBB is less stable in the peritumoural area of GM and metastatic brain tumours than it is in astrocytomas or normal brain. Osmotic BBB disruption may offer a method for achieving global delivery of therapeutic agents to brain tumours and peritumoural areas.

Clinical importance of c-Met protein expression in high grade astrocytic tumors

The clinical importance of the expression of c-Met protein, the receptor of hepatocyte growth factor/scatter factor, was evaluated in neuroepithelial tissue tumors. c-Met immunohistochemistry was performed using the streptavidin-biotin-peroxidase complex method with anti-c-Met polyclonal antibody. Specimens were classified as c-Met negative (< 30%) or c-Met positive (> or = 30%) according to the proportion of immunopositive cells under microscopic examination. All c-Met-positive cases occurred in high grade astrocytic tumors, not in other neuroepithelial tissue tumors. Most c-Met-positive astrocytic tumors were classified histologically as high grade tumors. Epidermal growth factor-receptor (EGFR) and MIB-1 immunohistochemistry were also performed for high grade astrocytic tumors. Survival analysis was performed for patients with these tumors with variables including c-Met positivity, EGFR positivity, and MIB-1 labeling index. Positivity of c-Met was independent from EGFR positivity and MIB-1 labeling index, and the c-Met-positive group showed a significant shorter survival (p < 0.05). c-Met immunopositivity may be a parameter of biological aggressiveness in high grade astrocytic tumors. Examination of c-Met expression in astrocytic tumors provides significant clinical information, especially as a prognostic factor.

Clinical evaluation of a portable digital hearing aid with narrow-band loudness compensation

A new portable digital hearing aid referred to as CLAIDHA (Compensate for Loudness by Analyzing Input-signal Digital Hearing Aid), which employs frequency-dependent amplitude compression based on narrow-band loudness compensation, was clinically evaluated in 159 subjects with hearing loss. The results of speech tests revealed better intelligibility compared with the subject's own hearing aids; the advantage of using CLAIDHA in daily life was also indicated by the results of a questionnaire completed by the subjects. In about 64% of the subjects with a flat, gradually sloping type of hearing loss, CLAIDHA was satisfactorily adopted for daily use. However, in the subjects with a steeply sloping type of hearing loss and subjects with losses mainly at high and low frequencies, with near-normal mid-frequency hearing. this loudness compensation scheme seems to be slightly less effective.

[FLAIR images of mild head trauma with transient amnesia]

A newly advanced MRI pulse sequence, the FLAIR (fluid-attenuated inversion recovery) imaging, in which a long TE spin echo sequence is used with suppression of the CSF with an inversion pulse, displays the CSF space as a no signal intensity area. We examined 45 cases of mild head trauma with posttraumatic amnesia by FLAIR images and could detect some findings which could not be detected by CT scan and conventional MR images. These findings could be detected in many patients with long post-traumatic amnesia (over 2 hours), but they could not be detected in patients with short posttraumatic amnesia (within 30 mins). These findings existed surrounding lateral ventricles and we classified them into 3 types: type 1 is anterior horn of lateral ventricle, type 2 is the base of frontal lobe, type 3 is cerebral deep white matter. Some of them were examined again by FLAIR images a month later, and these findings had disappeared. We suspect that these lesions were brain edema or mild contusion without hemorrhage.

Measurement of RBC velocities in the rat pial arteries with an image-intensified high-speed video camera system

The mean centerline red blood cell (RBC) velocity of the rat pial artery was measured using an image-intensified high-speed (1000 frames/s) video camera system and RBCs labeled with fluorescein isothiocyanate (FITC). Some investigations measuring RBC velocity have been made in most organs, but the RBC velocity of the pial artery has not yet been measured with this system using FITC labeled RBC. After recording the emission of the FITC labeled RBC through a closed cranial window using this system, the authors analyzed the videotape. The movement of each individual RBC for several milliseconds over a distance of 50 microm could be pursued. The mean centerline RBC velocity in normal rats varied between 1.0 and 9.0 mm/s (most of the measurements we taken in vessels ranging between 20 and 80 microm in diameter). As the diameter of the pial artery becomes smaller, the blood flow rate (pi x (diameter/2)2 x (mean centerline velocity/1.6)) tends to become smaller. During CO2 inhalation, the pial artery diameter, mean centerline RBC velocity, and blood flow rate increased with statistical significance. Mean centerline RBC velocities in the cerebral microcirculation could not be measured directly with accuracy using the older methods (30 frames/s). However, this method is useful for investigation of the cerebral microcirculation and is considered to be applicable for studying the behavior of leukocytes or platelets, which will be examined in a subsequent study.

Acute effects of combined administration of kanamycin and furosemide on the stria vascularis studied by distortion product otoacoustic emission and transmission electron microscopy

Acute effects of kanamycin and/or furosemide administration on the stria vascularis of the guinea pig cochlea were assessed by distortion product otoacoustic emission (DPOAE) and transmission electron microscopy. Kanamycin alone failed to affect the DPOAE levels and ultrastructural changes. Furosemide alone caused a rapid but reversible fall of the DPOAE levels. No remarkable pathological changes in the strial vascularis were observed after a complete recovery of the DPOAEs. On the other hand, furosemide injection following kanamycin with a 2 hour interval resulted in two patterns of significant changes in the DPOAEs, namely, a sudden drop in the DPOAE levels 2 to 3 hours after furosemide injection and a gradual fall in the DPOAE levels immediately after the incomplete recovery from the furosemide-induced decrease of the DPOAE levels. Ultrastructural changes in the stria vascularis included numerous vacuoles in the strial marginal cells and increased electron density of the intermediate and basal cells. These physiological and morphological changes in the stria vascularis may imply new ototoxic features induced by kanamycin potentiated by furosemide.

In situ phosphorylation of bone and dentin proteins by the casein kinase II-like enzyme

Our previous studies suggested the possibility of extracellular phosphorylation of matrix phosphoproteins into more phosphorylated forms by mature odontoblasts and osteocytes (Mikuni-Takagi et al., 1995; Satoyoshi et al., 1995). To elucidate such phosphorylation of bone and dentin proteins, we developed a histochemical method using frozen sections to determine the sites of enzymatic processing by the casein kinase II-like enzyme. It was observed that proteins in bone, dentin, and predentin are phosphorylated by the endogenous enzyme when the tissue slices were incubated with [gamma-32P] GTP, suggesting that there are both substrates and the enzyme in these matrices. In vivo, phosphate donors, ATP and GTP, may be supplied through dentinal canals and osteocyte canaliculi. Immunohistochemical analysis of frozen sections showed that the extremely intense staining of phosphoserine residues by anti-phosphoserine antibodies appeared in dentin only after demineralization of the tissue samples. It implies that these phosphoserine residues become bound to mineral as soon as the phosphorylation is completed, thereby being inaccessible to the antibodies without demineralization. The data support our notion that the extracellular phosphorylation of dentin/bone proteins, regulated by the developmental stages of bone and dentin cells, occurs prior to matrix mineralization.

[Analysis of abnormal findings observed on brain MRI T 2 weighted image in a system for the detection of asymptomatic brain disease in 1,200 cases]

In this study we described the significance of asymptomatic cerebral infarction (ACI) and periventricular hyperintensity (PVH) observed on brain MRI in a system for detection of asymptomatic brain disease with 1,200 cases. The risk factors (RF), population in each age bracket of ACI and PVH, among groups with hypertension (HTG) and without RF (no-RFG), were investigated. The RF of ACI were hypertension (HT), diabetes mellitus (DM), and aging. Without DM, those are common RF of PVH. The population of PVH and ACI with PVH increased with aging in no -RFG. On the other hand, only the population of ACI with PVH increased with aging in HTG. The rate of these abnormal findings in HTG was significantly higher than that in no-RFG. In addition, HT accelerated the occurrence of these findings by 10-20 years. When patients were over 60 years old, ACI increased rapidly. Accordingly, we concluded that (1) PVH and ACI had a common background. (2) Long term follow up concerning the incidence of ACI in the group with only PVH was necessary. (3) It was desirable that treatment for RF should be effected before the age of sixty.

Calcitonin gene-related peptide stimulates potassium efflux through adenosine triphosphate-sensitive potassium channels and produces membrane hyperpolarization in osteoblastic UMR106 cells

In previous studies, we have shown that calcitonin gene-related peptide (CGRP) acutely inhibits 45Ca2+ uptake in osteoblastic UMR106 cells, and we have proposed that ATP-sensitive potassium (K(ATP)) channels are involved in mediating this action of CGRP. To directly test this proposed mechanism, we have now examined the effects of CGRP on both membrane potential (Em) and K+ mobilization in UMR106 cells, using specific fluorometric dye assays. CGRP (0.01-100 nM) induced membrane hyperpolarization in a dose-dependent manner, with a half maximal effect (ED50) at approximately 0.2 nM and a maximal effect at 100 nM. Both pinacidil (Pina; a K(ATP) channel opener) and forskolin (FSK) induced similar membrane hyperpolarization, but the actions of these three agents could be easily distinguished: both CGRP and Pina actions were well antagonized by glibenclamide (Glib; a selective K(ATP) channel blocker), whereas FSK action was strongly attenuated only by tetraethylammonium (a K(Ca) channel blocker) or compound H-89 (an inhibitor of cAMP-dependent protein kinases). Cells pretreated with Pina no longer responded to CGRP, but they could still respond to FSK; furthermore, pretreatment with FSK failed to block successive treatment with either CGRP or Pina. In parallel with observed changes in Em, CGRP (0.01-100 nM) decreased intracellular K+ concentrations ([K+]i) in a dose-dependent manner, with an ED50 identical to that obtained for alterations in Em. This action of CGRP was sensitive to Glib and had only slight sensitivity to tetraethylammonium; this CGRP effect was mimicked by Pina but not by FSK. Interestingly, CGRP significantly elicited changes in cell shape by a Glib-sensitive mechanism that included notable decreases in cross-sectional cytoplasmic area. These observations strongly support our proposal that CGRP primarily stimulates K+ efflux via activation of K(ATP) channels and thereby induces membrane hyperpolarization in UMR106 cells. Furthermore, our data also suggest that this cascade of initial cellular events may result in rapid changes in cell morphology and decreases in cellular area of the type that are thought to act as triggers for proliferation and/or differentiation in many cellular phenotypes.

Long-latency response to transcranial magnetic stimulation in patients with hemifacial spasm

OBJECTIVE

We studied the long-latency response of the orbicularis oris muscle elicited with transcranial magnetic stimulation in patients with hemifacial spasm (HFS) and evaluated the excitability of the facial nucleus.

METHODS

We compared the thresholds on both sides in 8 normal volunteers and 7 patients with hemifacial spasm. The thresholds were determined as the lowest intensity required to produce motor evoked potentials with an amplitude of at least 50 microV in the orbicularis oris muscle. Average values were given as means +/- standard deviation. Wilcoxon's rank sum test was used for comparisons between the sides of normal subjects and of patients with HFS with respect to the threshold stimulus.

RESULTS

There was no significant difference between the thresholds on the two sides of the normal subjects (mean 1.88+/-5.30%, P > 0.05). In patients with HFS, there was a significant difference between the thresholds on the spasm side and the normal side (mean 20.7+/-13.0%, P < 0.05) In one patient studied after MVD, the difference between both sides disappeared.

CONCLUSION

The difference between the thresholds in patients with HFS and the normalization in threshold after MVD suggested that the mechanism of HFS was hyperexcitability of the facial nucleus.

Periodontal ligament cell culture on the hydrophobic substrate coated with proteins of periodontal ligament fibroblast-conditioned medium

In regenerating periodontal ligament (PDL) around the root of an artificial tooth, an important role is played by some physiologically active substance that promotes adhesion of the cells to the surface of the tooth root and induces cell proliferation and differentiation. In this study, the supernatant of the conditioned medium (CM) of dog periodontal ligament fibroblast (DPLF) was fractionated using an ion exchange chromatography-diethylaminoethyl (IEC-DEAE) column. DPLFs were cultured on hydrophobic dishes coated with each fraction. Cell proliferative activity and alkaline phosphatase (ALPase) activity, including electron microscopic features of the contact surface between the cells and the dish, were investigated. The DPLF-CM was separated by IEC-DEAE column into six fractions. Each fraction promoted an increase in DNA content and ALPase activity of the cultured DPLF, and especially remarkable were fractions 2 and 3. Fraction 2 at a molecular weight (Mw) of 210, 160, 85, 50 and 22 kD, and fraction 3 at Mw = 21 and 23 kD contained the type of proteins not found in other fractions. Electron microscopic analysis revealed that the cells in the coating group were in close contact with the surface of the dishes and that fine fibers protruding from the cell membrane clinged to the dishes. In the control group, a wide gap between the cells and the dishes was observed. These findings suggest that the DPLF-CM fractions contain specific physiological activating factors that induce proliferation and differentiation as well as cell adhesion of the DPLF cells.

Transcranial magnetic stimulation of the oculomotor and abducens nerves: determining the site of excitation in the cat

The authors have attempted to stimulate the feline oculomotor and abducens nerves using a magnetic coil (MC) and to determine the optimal reliable MC position for eliciting motor evoked potentials. The authors have also determined the site of excitation to analyze the validity and potential advantages of this technique as a means of neurophysiologically studying the oculomotor and abducens nerves. The potentials of both of these muscles are evoked by MC placed to be symmetrical to the line connecting the vertex and the center of the eyeball on the side being examined, as the coil center corresponds to the midpoint of this line. The latencies of the motor responses of the superior rectus and lateral rectus were 1.08 +/- 0.22 and 1.02 +/- 0.21 msec, respectively, suggesting that magnetic stimulation excites both the oculomotor and the abducens nerve at the superior orbital fissure.

Up-regulation of inducible nitric oxide (NO) synthase and NO production in HL-60 cells stimulated to differentiate by phorbol 12-myristate 13-acetate plus 1,25-dihydroxyvitamin D3 is not obtained with dimethylsulfoxide plus 1,25-dihydroxyvitamin D3

In previous studies we found that the calciotropic hormone 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] augments the action of either prostaglandin E1 (PGE1) or NaF to induce differentiation of human promyelocytic HL-60 cells, a process that features increased generation of nitric oxide (NO) via up-regulation of inducible nitric oxide synthase (iNOS). We have now examined the short-term interaction of 1,25(OH)2D3 with phorbol 12-myristate 13-acetate (PMA) and dimethylsulfoxide (DMSO) in these cells. PMA (100 nM) alone generally up-regulated several classical indices of macrophagic differentiation and stimulated cellular production of interleukin (IL)-1alpha, IL-6, tumor-necrosis factor (TNF)-alpha, PGE2, and NO. Increased generation of NO primarily resulted from increased expression of cellular iNOS. When 1,25(OH)2D3 (10 nM) was added to PMA treatments, most PMA-induced changes, particularly its effects to up-regulate iNOS-dependent NO production and change cell morphology, were multiplicatively augmented. In contrast, DMSO (1.3%) alone, an inducer of granulocytic differentiation, increased cytokine production, but failed to stimulate NO production or induce iNOS. In contrast to its striking interaction with PMA, 1,25(OH)2D3 could not augment DMSO's differentiative effects. Changes in cellular cytokine production were eliminated as the driving force in HL-60 differentiation when specific neutralizing antibodies failed to produce any attenuation of iNOS up-regulation or of the shifts in cell morphology. However, indomethacin (30 microM) blocked the synergistic interaction between 1,25(OH)2D3 + PMA to shift cell morphology and stimulate NO production. Subsequently adding PGE2 (1 ng/ml) to indomethacin-treated cells restored the ability of 1, 25(OH)2D3 + PMA to interactively increase cellular NO production, but failed to fully replicate the strong shift in cell morphology typical of PMA + 1,25(OH)2D3 treatments. Our findings suggest that interaction between 1,25(OH)2D3 and PMA to induce macrophagic differentiation increases iNOS-dependent NO production by a mechanism involving a cyclooxygenase product(s), possibly PGE2.

The acoustic reflex for filtered broadband stimuli: a lesser contribution of the lower frequency neurons

The effects of the cut-off frequency of the filtered broadband stimuli on the human acoustic reflex (AR) were examined to observe the relation between the area of excitation in the cochlea and the AR response. The results obtained have indicated that all the input from the cochlear region does not equally contribute to trigger the AR equally; i.e., there is a lesser contribution from the frequency region below 700 Hz.