A review of the literature on the efficacy of mineral trioxide aggregate in conservative dentistry

The aim of this literature review was to assess the clinical performance of MTA to establish the evidence level for its effectiveness in vital pulp therapy, perforation repair, and retrograde root canal filling. A comprehensive literature survey was performed via electronic databases of PubMed/MEDLINE. A total of 58 papers were reviewed in this study, of which 2 were systematic reviews/meta-analysis, 9 were randomized controlled trials (RCTs), and the rest were fallen into other categories. Mineral trioxide aggregate (MTA) provided better pulp protection as a direct capping material when compared with calcium hydroxide. As perforation repair materials, MTA demonstrated an excellent sealing ability in vitro. For periodontal tissues around a perforation, MTA provided normal healing processes in clinical trials. It is therefore concluded that MTA has a high potential in repairing perforations. MTA is the most promising material when used for retrograde root canal filling demonstrating normal healing in short/long term clinical outcomes.

Concept and clinical application of the resin-coating technique for indirect restorations

The resin-coating technique is one of the successful bonding techniques used for the indirect restorations. The dentin surfaces exposed after cavity preparation are coated with a thin film of a coating material or a dentin bonding system combined with a flowable composite resin. Resin coating can minimize pulp irritation and improve the bond strength between a resin cement and tooth structures. The technique can also be applied to endodontically treated teeth, resulting in prevention of coronal leakage of the restorations. Application of a resin coating to root surface provides the additional benefit of preventing root caries in elderly patients. Therefore, the coating materials have the potential to reinforce sound tooth ("Super Tooth" formation), leading to preservation of maximum tooth structures.

Phosphorus flame retardants in indoor dust and their relation to asthma and allergies of inhabitants

Organophosphate esters are used as additives in flame retardants and plasticizers, and they are ubiquitous in the indoor environment. Phosphorus flame retardants (PFRs) are present in residential dust, but few epidemiological studies have assessed their impact on human health. We measured the levels of 11 PFRs in indoor floor dust and multi-surface dust in 182 single-family dwellings in Japan. We evaluated their correlations with asthma and allergies of the inhabitants. Tris(2-butoxyethyl) phosphate was detected in all samples (median value: 580 μg/g in floor dust, 111 μg/g in multi-surface dust). Tris(2-chloro-iso-propyl) phosphate (TCIPP) was detected at 8.69 μg/g in floor dust and 25.8 μg/g in multi-surface dust. After adjustment for potential confounders, significant associations were found between the prevalence of atopic dermatitis and the presence of TCIPP and tris(1,3-dichloro-2-propyl) phosphate in floor dust [per log10 -unit, odds ratio (OR): 2.43 and 1.84, respectively]. Tributyl phosphate was significantly associated with the prevalence of asthma (OR: 2.85 in floor dust, 5.34 in multi-surface dust) and allergic rhinitis (OR: 2.55 in multi-surface dust). PFR levels in Japan were high compared with values reported previously for Europe, Asia-Pacific, and the USA. Higher levels of PFRs in house dust were related to the inhabitants' health status.

Relationships between mite allergen levels, mold concentrations, and sick building syndrome symptoms in newly built dwellings in Japan

This study investigated the possible relationships between exposures to mite allergen and airborne fungi with sick building syndrome (SBS) symptoms for residents living in newly built dwellings. We randomly sampled 5709 newly built dwellings in six prefectures from northern to southern Japan. A total of 1479 residents in 425 households participated in the study by completing questionnaire surveys and agreeing to environmental monitoring for mite allergen (Der 1), airborne fungi, aldehydes, and volatile organic compounds. Stepwise logistic regression analyses adjusted for confounders were used to obtain odds ratios (OR) of mite allergen and fungi for SBS symptoms. Der 1 had a significantly high OR for nose symptoms. Rhodotorula had a significantly high OR for any symptoms, and Aspergillus had significantly high OR for eye symptoms. However, the total colony-forming units had a significantly low OR for throat and respiratory symptoms. Eurotium had a significantly low OR for skin symptoms. In conclusion, dust-mite allergen levels and indoor airborne Rhodotorula and Aspergillus concentrations may result in SBS symptoms in newly built dwellings.

PRACTICAL IMPLICATIONS

Various factors can cause sick building syndrome symptoms. This study focused on biologic factors such as dust-mite allergen and airborne fungi in newly built dwellings in Japan. Dust-mite allergen levels were significantly associated with higher rates of nose symptoms, airborne Rhodotorula concentrations were significantly associated with higher rates of any symptoms, and Aspergillus concentrations were significantly associated with higher rates of eye symptoms. Measures should be taken to reduce mite allergen levels and fungal concentrations in these dwellings.

Regional differences in residential environments and the association of dwellings and residential factors with the sick house syndrome: a nationwide cross-sectional questionnaire study in Japan

This study was conducted to clarify regional differences in residential factors and the association of those factors with dwellings having sick house syndrome (SHS) problems. The survey was conducted in six areas of northern and southern Japan. In terms of regional differences, dampness was not as severe in the dwellings in Sapporo as compared with that in areas in the south. SHS was defined using five categories of nasal, throat and respiratory, skin and general symptoms, which appeared frequently or not frequently and improved upon leaving the home. The dampness index was estimated by the sum of the presence of several indicators: condensation on the window panes and/or wall, visible mold growth, moldy odor, slow-drying wet towels in the bathroom, and water leakage. The dwellings where inhabitants showed any symptoms of SHS comprised 3.7% of all surveyed dwellings. We found significant associations between SHS and dampness index, odors, and stuffiness of the air. For dampness, the adjusted odds ratio (OR) increased with increased dampness index, adjusting for the age of the house, pets indoors, stuffiness of the air, and odors. These results showed an increased risk when several dampness indicators appeared simultaneously.

PRACTICAL IMPLICATIONS

To evaluate the associations of residential environments and Sick House Syndrome (SHS), this cross-sectional questionnaire study was conducted on 2297 dwellings in six areas in Japan from 2003 to 2004. The dwellings where inhabitants showed any of nasal, throat and respiratory, skin and general symptoms comprised 3.7% of all surveyed dwellings, and an increased risk for SHS was found when several dampness indicators, 'condensation', 'visible mold growth', 'moldy odor', 'slow drying wet towels in the bathroom' and 'water leakage', appeared simultaneously.

Dose measurement on both patients and operators during neurointerventional procedures using photoluminescence glass dosimeters

BACKGROUND AND PURPOSE

Although radiation skin injuries associated with interventional radiology have been known as a critical issue, there are few reports mentioning direct measurement of the entrance skin dose (ESD). Thus, the purpose of this study was to clarify the regional distributions of ESDs in neurointervention.

MATERIALS AND METHODS

Using photoluminescence glass dosimeters (PLDs), we measured the ESDs in 32 patients with a median age of 61.5 years. Angiographic parameters, including exposure time, dose-area product (DAP), and the number of digital subtraction angiography (DSA) studies and frames, were recorded. The ESDs of operators were analyzed by the same method.

RESULTS

The maximum ESD of 28 therapeutic procedures was 1.8 +/- 1.3 Gy. Although the averaged ESD on the right temporo-occipital region was higher than that in other regions, disease-specific patterns were not observed. Statistically positive correlations were found between the maximum ESD and exposure time (r = 0.5283, P = .005), DAP (r = 0.7917, P < .001), the number of DSA studies (r = 0.5636, P = .002), and the number of DSA frames (r = 0.8583, P < .001). As for operators, ESDs to the left upper extremity were significantly higher than those to other regions. However, most of the ESDs were <0.2 mGy. Lead protective garments reduced the exposure doses to approximately one half to one tenth.

CONCLUSION

It was shown that the regional ESD could be measured by applying the PLD. This method should contribute to reducing the dose accumulation in patients as well as in operators.

Retreatment of cerebral aneurysms after guglielmi detachable coil embolization

SUMMARY

Of 175 patients with 181 aneurysms initially treated with Guglielmi Detachable Coils (GDC), 25 were retreated. All retreatments except one were performed on previously ruptured aneurysms. Thirteen aneurysms were retreated because of recurrence, and 12 aneurysms were retreated to complete initial insufficient embolization. Sixteen patients underwent re-embolization and 9 patients were operated upon surgically. No complications related to the retreatment were experienced. We consider that repeat embolization should be attempted before considering surgical treatment in case that additional therapy is required. However, it is difficult to retreat aneurysms having wide necks. In regard to surgical clipping, aneurysms without a coil in the neck are easier to treat with primary clipping, whereas aneurysms with a coil mass in the neck are difficult to surgical clip. We have never used temporary clipping and coil extraction if the distance between the coil and the parent artery was wider than 2 mm. Emerging new embolic agents or devices and technical improvement might decrease the need for retreatment and increase long-term efficacy after endovascular treatment.

Angiographical change of guglielmi detachable coils. Treated cerebral aneurysm in acute stage

SUMMARY

Acute angiographical changes for preventing acute rebleeding on GDC treated cerebral aneurysms were evaluated. From December 2000 to November 2002, 48 total aneurysms in 44 consecutive patients with acute SAH. Acute angiographical evaluations were carried out in 46 aneurysms, including 42 ruptured and 4 unruptured aneurysms. Two cases were excluded because of poor medical condition. In this series, there were no rebleeding cases in acute stage. In the initial embolization for the 46 aneurysms, CO was achieved in eight aneurysms, NR in 15 aneurysms and BF in 23 aneurysms. Acute angiographical observations showed progressive thrombosis in 17 aneurysms (37%). No changes were observed in remaining 29. No recanalization was observed in this series. Only one case of BF, inside the aneurysm bleb was still observed during follow up. Additional embolization was carried out. Progressive thrombosis was frequently observed in GDC treated cerebral aneurysms during acute stage. This angiographical finding seems to show prevention of rebleeding, which is considered important for the management of GDC treatment in acutely ruptured cerebral aneurysm.

Percutaneous transluminal angioplasty for atherosclerotic stenoses of intracranial vessels

SUMMARY

To study the efficacy and long-term outcome of percutaneous transluminal angioplasty (PTA) with/without stent placement for intracranial atherosclerotic stenoses, we reviewed our treated cases retrospectively. Between May 1992 and October 2003, PTA with/without stents was performed in 64 intracranial and skull base vessels in 62 patients, including 24 middle cerebral arteries, 16 internal carotid arteries, 13 vertebral arteries, and 11 basilar arteries. PTA was technically successful in 55 vessels (86%). However, four vessels (6%) failed to achieve satisfactory dilatation. We encountered five periprocedural strokes as symptomatic complications, for a mortality rate of 4.7% and a morbidity rate of 3.1%. All the patients with stent placements survived angioplasty without any complication. In the clinical follow-up available for one week to 11.5 years (mean, 4.7 years), there were three strokes related to the treated vessels. The annual stroke rate in the affected territory was estimated at 1.2% per year. According to these results, PTA for intracranial atherosclerotic stenoses seems to be a beneficial therapy for immediate anatomical results and long-term stroke prevention. Stent-assisted PTA could help patients achieve successful dilatation and avoid complications.

Elastic coefficient of a single polymer chain by using Brownian dynamics analysis

The elastic coefficient of a single polystyrene chain has been experimentally evaluated by using Brownian dynamics analysis. The Brownian motion of the chain is probed using a particle trapped by optical tweezers with a negligibly small spring constant. The displacement of the particle due to Brownian motion is measured by an interferometer assembled using the same laser beam as the optical tweezers. Two methods are employed for Brownian dynamics analysis: (1) the analysis of the time course of the displacement of the particle and (2) the fitting of the power spectrum of Brownian motion with a Lorentzian. The elastic constant of a polystyrene chain in dichloromethane at 21 degrees C is estimated to be 6.4 x 10(-6) and 1.1 x 10(-5) N/m when methods (1) and (2) are employed, respectively. The elastic constant obtained by approximating the polystyrene chain to a freely jointed chain is in agreement with the experimentally evaluated elastic constant.

Efficacy of carotid artery stenting

SUMMARY

Carotid Artery Stenting(CAS) was performed for 51 lesions in 46 patients for almost clinically symptomatic stenotic (> 70%)lesions of cervical carotid arteries. The lesions involved the contralateral occlusion cases in eight cases, the bilateral stenotic cases in six cases and the ipsilateral internal carotid artery stenotic cases in two cases. In all cases, endovascular technique was performed from a transfemoral approach under local anesthesia primarily. Under systemic heparinization, CAS was performed using a selfexpanding stent system. For the pre-stenting and post-stenting dilatation, percutaneous transluminal angioplasty (PTA) balloon catheters were used. The balloon was inflated up to the pressure of six to ten atoms for 20 to 30 seconds.After CAS, stenotic lesion dilated successfully in all cases (0-20% residual stenosis; mean, 5.5%) even if in the case of the contra-lateral occlusion cases, more than 90% severe stenotic cases, and the tortuous artery cases. The cerebral protection system was always used, mainly distal blocking balloon type. Only one symptomatic complication occurred after CAS. Follow-up ultrasonic carotid echogram was performed in 30 cases.No cases showed restenosis (more than 50% restenosis). Clinical follow up was performed in all cases for one to 41 months (mean, 15.2 months) and no clinical deterioration such as TIA or stroke occurred. CAS is technically feasible and can be performed with relatively low morbidity even if complicated stenotic cases. It may be useful, but the increase the number of patients and the long-term follow-up are necessary to evaluate the safety and usefulness of this method.

Influence of light intensity on dentin bond strength of self-etch systems

The purpose of this study was to investigate the influence of light intensity on dentin bond strengths of four self-etch adhesive systems. The light intensities used to polymerize specimens were controlled at levels of 150, 300, 600, and 900 mW/cm2. The two-step self-etch adhesive systems Imperva Fluoro Bond and Mac Bond II, and the one-step self-etch systems Fluoro Bond Shake-One and One-Up Bond F Plus were used with their corresponding light-cured resins. Labial surfaces of lower bovine incisors were ground with #600 grit SiC paper to expose the dentin. The dentin surfaces were treated according to each manufacturer's instructions and bonded with resin composites. A shear bond strength test was performed and the data were analyzed by one-way ANOVA followed by Newman-Keuls multiple comparison at a level of 0.05. Statistical analysis of the data indicated that light intensity affected the dentin bond strengths of the adhesive systems tested. Significantly lower bond strengths were obtained by exposure to 150 mW/cm2, and there were no differences between the bond strengths obtained at 600 and 900 mW/cm2 for all the adhesive systems used. Further research will be required to clarify the irradiance-dependent properties of light-cured resin adhesive systems.

Mechanical properties of artificial tracheas composed of a mesh cylinder and a spiral stent

Much work has been done on the materials used for mesh-type artificial tracheas, but a precise mechanical evaluation of these structures has not yet been performed. In the present study, we determined the mechanical properties of typical mesh-type artificial tracheas and compared them with those of native trachea. Four types of artificial trachea were made and used for the mechanical tests. The basic frame of all the specimens was composed of a mesh cylinder and a spiral stent. The specimen whose mesh was sealed with collagen sponge showed almost the same behavior in the force-strain curve under compression, suggesting that collagen sealing has little effect on mechanical properties. Agreement between measured and estimated mechanical properties was good, especially in the low strain region, suggesting that artificial tracheas can be designed in terms of mechanical properties by mainly considering the basic frame structure.

GABA-evoked chloride currents do not differ between dendrites and somata of rat neocortical neurons

1. We performed patch-clamp recordings on acutely isolated somata and dendritic segments of rat neocortical neurons, in order to compare the reversal potential (E(GABA)) and relative density of GABA(A) receptor-mediated Cl(-) currents in these two cellular compartments. 2. Currents were recorded with the Cl(-)-impermeable pore former gramicidin (25--75 microg ml(-1)) in HCO(3)(-)-free bath solution. Voltage ramps (-110 to -30 mV) from a holding potential (V(h)) of -60 mV in the absence and presence of 2 microM GABA were used to construct instantaneous current-voltage relationships. Currents were abolished by co-application of GABA with the GABA(A) receptor antagonist bicuculline (40 microM). 3. GABA conductance, normalized to membrane surface area, was not different in somata and dendrites. In addition, E(GABA) was not different in the two compartments. 4. Replacement of intracellular K(+) with Cs(+) resulted in a significantly more depolarized E(GABA) in both somata and dendrites. These results suggest that the resting intracellular Cl(-) concentration ([Cl(-)](i)) is similar in somata and dendrites and that an outward Cl(-) transporter system maintains low [Cl(-)](i).

Increases in K+ conductance and Ca2+ influx under high glucose with suppressed Na+/K+-pump activity in rat myelinated nerve fibers

To test the combined effect of high glucose and decreased Na+/K+-pump activity, a condition which closely mimics the diabetic state, on nerve ionic currents, changes in action potential and membrane current induced by high glucose in the presence of ouabain were investigated using voltage clamp analysis in rat single myelinated nerve fibers. In the presence of 0.1 mM ouabain, 30 mM glucose caused a progressive increase in the delayed K+ current as well as persistent decreases in action potential and Na+ current, suggesting that Na+/K+ pump plays an important role in preventing the increase in the K+ current. The latter increase was suppressed by a blocker of Ca2+-activated K+ channels. Two types of voltage-dependent Ca2+ channel blockers (L and N-type) as well as a Na+/Ca2+-exchange blocker diminished the ouabain-induced increase in K+ conductance. These results suggest that high glucose with suppressed Na+/K+ pump activity might induce an increase of Ca2+ influx through either Ca2+ channels or reverse Na+/Ca2+-exchange, possibly leading to the elevation of Ca2+-activated voltage-dependent K+ channels. Both a decrease in inward Na+ current and an increase in K+ conductance may result in decreased nerve conduction. In addition, a possible increase of axoplasmic Ca2+ concentration may lead to axonal degeneration. These results provide a clue for understanding the pathophysiologic mechanism of diabetic neuropathy.

Swelling and flow properties of tubular poly(vinyl alcohol) gels

Swelling and flow properties of tubular poly(vinyl alcohol) (PVA) hydrogels prepared with the cooling method were investigated using an inflation testing method. When the tubular hydrogel in liquid paraffin was inflated by using liquid paraffin as a pressure transmitting medium, namely in the case that the liquids inside and outside the gel are both liquid paraffin (P/P combination), the gel showed a slight volume change determined by Poisson's ratio of the gel. When the gel in water was inflated by liquid paraffin (P/W combination), the gel swelled to large extent compared with the case of P/P. The hydrogel in W/W combination, namely in the situation that the gel was immersed in water and also inflated by water, showed a very large volume change if the comparison was done at the same pressure. The origin of the volume change in P/P, P/W and W/W combinations is discussed. The volume change in P/P was governed by the Poisson ratio as a material constant (mu 0) of the PVA gels, and the gels swelled by the change in the application of pressure (or deformation) in P/W. The volume change in W/W was closely related to the flow of solvent in the gel.

The sera from GM1 ganglioside antibody positive patients with Guillain-Barré syndrome or chronic inflammatory demyelinating polyneuropathy blocks Na+ currents in rat single myelinated nerve fibers

OBJECTIVE

To determine the possible role of anti-GM1 ganglioside antisera from patients with Gullain-Barr*e syndrome (GBS) or chronic inflammatory demyelinating polyneuropathy (CIDP) in the development of nerve dysfunction.

METHODS

The effect of the anti-GM1 antibody positive antisera obtained from 4 GBS patients and 1 CIDP patient on membrane potential and ionic currents in rat single myelinated nerve fibers was investigated using the voltage clamp technique and compared with that of the anti-GM1 negative antisera obtained from 3 healthy controls and 2 GBS patients.

RESULTS

In the presence of active complement, anti-GM1 positive antisera from 5 patients including 4 GBS patients and 1 CIDP patient significantly suppressed Na+ current more than anti-GM1 negative antisera.

CONCLUSION

This study supports the notion that anti-GM1 antibody is one of the causative factors of conduction abnormality in GBS patients.

[Effects of message and personal involvement on risk perception and acceptance]

The present study analyzed people's risk perception regarding driving a car with studded or non-studded winter tires. Subjects were 252 residents of Sapporo, where a recent municipal ordinance prohibited studded tires, allowing only non-studded ones. Questionnaire data were examined concerning (1) the relationship between risk perception and its acceptance, (2) the effect of an inserted message, which was either positive or negative about the use of non-studded tires, and (3) the role of personal involvement, assessed with Personal Involvement Inventory (Zaichkowsky, 1985), regarding winter driving. Results were as follows: (1) The use of non-studded tires was favorably judged because of social benefit, but subjects hesitated to choose them because of a higher perceived possibility of an accident. (2) The inserted message had significant effects on benefit evaluation and perceived accident possibility. The effects were weaker for drivers who had experienced driving a car with studded tires. And (3) personal involvement had a weak correlation with risk judgements of the present study.

Variance analysis of current fluctuations of adenosine- and baclofen-activated GIRK channels in dissociated neocortical pyramidal cells

Whole cell recordings were obtained from pyramidal cell somata acutely isolated from rat neocortex. In voltage-clamp mode, adenosine (0.3-1000 microM), and the GABA(B) receptor agonist, baclofen (1-300 microM), induced K+ current responses mediated by G protein-activated inwardly rectifying K+ (GIRK) channels. In our preparation, adenosine activated GIRK currents with an average EC(50) of 2 microM. Baclofen had an average EC50 of 26 microM. To estimate and compare unitary conductance and density of GIRK channels activated by either adenosine or baclofen, we performed variance analysis of current fluctuations associated with the application of the two agonists at increasing concentrations. Irrespective of the agonist tested, GIRK channels displayed an average single-channel conductance of 25 pS at our recording conditions ([K+]o: 60 mM). Assuming that GIRK channel conductance increases in proportion to the square root of [K+]o, this would translate into 5-6 pS at physiological ion gradients. GIRK channels activated by adenosine or baclofen were not only identical in terms of unitary conductance, they also displayed the same average density of 0.5 channels micron(-2) for both agonists. Our data strongly suggest that the two compounds recruit the same type of channel and thus most likely share a common transduction and effector system.

G protein-activated inwardly rectifying K+ (GIRK) currents in dendrites of rat neocortical pyramidal cells

1. We performed patch-clamp recordings on acutely isolated dendritic segments and cell somata of rat neocortical pyramidal neurons to determine and compare the relative density of G protein-activated K+ (GIRK) currents in the two cellular compartments. 2. Hyperpolarizing voltage ramps and elevation of extracellular K+ concentration to 40 mM served to identify inwardly rectifying K+ currents. Near-saturating concentrations of adenosine (100 microM), baclofen (20 microM) and serotonin (20 microM) all produced robust GIRK currents in cell somata as well as in dendritic segments that were completely abolished by Ba2+ (200 microM). In addition to agonist-activated GIRK currents, both somata and dendrites displayed a constitutive Ba2+-sensitive inward rectification. 3. In order to compare the relative strengths of GIRK current responses in the two compartments, GIRK conductance was normalized to surface area. In contrast to intrinsic, G protein-independent inward rectification, which was comparable in size in the two compartments, all three agonists evoked significantly larger GIRK conductances in dendrites than in somata. 4. Our data suggest that several neurotransmitters might employ GIRK currents as a tool to directly modulate the electrical properties of dendrites. In concert with voltage-dependent K+ currents and the hyperpolarization-activated cation current (Ih) of the dendrite, GIRK currents should dampen dendritic excitability and thus influence various aspects of dendritic signal integration.

Confocal calcium imaging reveals an ionotropic P2 nucleotide receptor in the paranodal membrane of rat Schwann cells

1. The paranodal Schwann cell region is of major importance for the function of a myelinated axon. In the present study we searched for a possible ionotropic effect of extracellular ATP in this Schwann cell compartment. 2. Whole-cell patch-clamp recordings from cultured rat Schwann cells revealed that ATP and 2'-3'-O-(4-benzoylbenzoyl)-adenosine 5'-triphosphate (BzATP) induced a non-specific cation current. The effect of ATP was much enhanced in a Ca2+- and Mg2+-free solution. ADP, UTP and alpha,beta-methylene adenosine 5'-triphosphate (alpha,beta-meATP) had no effect. 3. Confocal Ca2+ imaging of myelinating Schwann cells in isolated rat spinal roots showed a BzATP-induced rise in the free intracellular Ca2+ concentration in the paranodal Schwann cell cytoplasm whereas alpha,beta-meATP and 2-(methylthio)-adenosine 5'-triphosphate were without effect. In contrast to the known metabotropic effect of UTP on these Schwann cell regions, the BzATP-induced Ca2+ signal was not transient, was unaffected by depletion of intracellular Ca2+ stores and dependent on the presence of extracellular Ca2+. 4. These results suggest that an ionotropic ATP receptor with electrophysiological and pharmacological characteristics of the P2X7 subtype of nucleotide receptors is functionally active in myelinating Schwann cells of peripheral nerves. Such a receptor might contribute to Schwann cell reactions in nerve injury or neuropathy.

Inhibition of S-warfarin metabolism by nonsteroidal antiinflammatory drugs in human liver microsomes in vitro

We studied the inhibition of S-warfarin metabolism by nonsteroidal antiinflammatory drugs (NSAIDs) in human liver microsomes in vitro. After screening for potential inhibitors among ten NSAIDs using human recombinant cytochrome P450, inhibition kinetic parameters were estimated using human liver microsomes. Phenylbutazone and bucolome were suggested to increase the unbound steady-state level of S-warfarin about four- and five-fold, respectively, as estimated from these metabolic parameters.

Cortical myoclonus: sensorimotor hyperexcitability

Cortical or cortical reflex myoclonus is characterized by abnormally enlarged cortical somatosensory evoked potentials (giant SEPs), which most likely reflect pathologically hyperexcitable sensorimotor cortex. To clarify the pathogenesis of myoclonus of cortical origin, we simultaneously recorded SEPs and whole head somatosensory evoked magnetic fields (SEFs) following electric stimulation of the median nerve at the wrist in six patients with cortical myoclonus. N20m and enlarged P30m were observed in all patients and were localized at the posterior bank of the central sulcus (Brodmann area 3b of the primary somatosensory cortex). In addition, P25m and N35m components of SEFs were recognized in five and four patients, respectively. P25m component, that is, the magnetic counterpart of P25 in EEG, was the earliest cortical component showing enhancement in patients. Multidipole analysis combined with magnetic resonance imaging (MRI) coregistration revealed that the generators of P25m were in the precentral gyrus in four patients and in the postcentral gyrus in one patient. The second SEFs around 200 msec after the single stimulus were recorded in three patients at area 3b (repetitive SEFs); two of whom showed negative as well as positive myoclonus. The importance of motor cortex for the generation of cortical reflex myoclonus was thus demonstrated. The pathologic features of SEFs suggest abnormal excitability of primary sensorimotor cortex.

Skeletal overgrowth in transgenic mice that overexpress brain natriuretic peptide

Longitudinal bone growth is determined by the process of endochondral ossification in the cartilaginous growth plate, which is located at both ends of vertebrae and long bones and involves many systemic hormones and local regulators. Natriuretic peptides organize a family of three structurally related peptides: atrial natriuretic peptide, brain natriuretic peptide (BNP), and C-type natriuretic peptide. Atrial natriuretic peptide and BNP are cardiac hormones that are produced predominantly by the atrium and ventricle, respectively. C-type natriuretic peptide occurs in a wide variety of tissues, where it acts as a local regulator. These peptides can influence body fluid homeostasis and blood pressure control through the activation of two guanylyl cyclase (GC)-coupled natriuretic peptide receptor subtypes-GC-A and GC-B. We report here marked skeletal overgrowth in transgenic mice that overexpress BNP. Transgenic mice with elevated plasma BNP concentrations exhibited deformed bony skeletons characterized by kyphosis, elongated limbs and paws, and crooked tails. Bone abnormalities resulted from a high turnover of endochondral ossification accompanied by overgrowth of the growth plate. Studies using an in vitro organ culture of embryonic mouse tibias revealed that BNP increases the height of cartilaginous primordium directly, thereby stimulating the total longitudinal bone growth. The present study demonstrates that natriuretic peptides can affect the process of endochondral ossification.

A special blocker reveals the presence and function of the hyperpolarization-activated cation current IH in peripheral mammalian nerve fibres

Electrotonic responses recorded extra- or intracellularly from peripheral nerve preparations show a "sag" to hyperpolarizing current pulses. The biophysical nature of this "inward rectification" is still under discussion since the phenomenon has not been noted at voltage-clamped single nerve fibres, and since Cs+, which reduces inward rectification, is not a specific ion channel blocker. In this study, we found that low micromolar concentrations of ZD 7288, a specific blocker of the hyperpolarization-activated cationic current (Ih) in the soma of central mammalian neurons, result in a complete block of inward rectification in the electrotonic responses of isolated rat spinal dorsal roots. In addition, ZD 7288 enhanced the activity-dependent slowing of conduction seen in compound C fibre action potentials of isolated rat vagus nerves and augmented the post-tetanic hyperpolarization following trains of action potentials in unmyelinated and myelinated axons. The data suggest that ZD 7288 is a potent blocker and a useful research tool for the study of hyperpolarization-activated inward rectification (Ih) of peripheral nerve preparations.

A case of hemangiopericytoma of the buccal mucosa

We report a 46-year-old woman who presented with a hemangiopericytoma in the buccal mucosa. At the 2-year postoperative examination, there was no evidence of recurrence or metastasis. The findings in the present case are compared with previous reports in the Japanese literature, with regard to patient age and sex, and lesion size, location, malignancy, local recurrence and metastasis.

[A case of cortical reflex myoclonus manifesting tremor]

A 58-year-old woman developed slowly progressive tremulous myoclonus provoked mainly by action and posture. She had neither seizure nor dementia. No one in her family had similar symptoms. The presence of giant somatosensory evoked potentials (SEP) with enhanced long loop reflex and premovement cortical spikes demonstrated by the jerk-locked averaging method suggest that the involuntary movement is cortical reflex myoclonus. Magnetoencephalogram revealed that the generator sources of giant SEPs were the post-central somatosensory cortex and probably also the pre-central motor cortex. Symptoms improved after treatment with zonisamide, clonazepam and valpolate. This kind of involuntary movement might be called cortical myoclonic tremor.

Characteristic expression of high molecular mass heat shock protein HSP105 during mouse embryo development

Expression of 105 k-Da heat shock protein (HSP105) during mouse embryo development was investigated. Although HSP105 was detected scarcely in mouse embryos at gestational day (GD) 8, its level of HSP105 increased markedly in the embryos from GD 9 to 11, and then decreased gradually by GD 14. In contrast, 70 k-Da heat shock cognate protein (HSC70) was detected at constantly high levels in embryo from GD 8 to 17 (before birth). The transient increase in level of HSP105 was observed in most embryonic tissues. Since the levels of HSP105 mRNA was detected at constantly high levels in the embryos between GD 8 and 12, the increased expression of HSP105 at GD 9 to 11 seemed to be regulated at posttranscriptional level. Immunohistochemically, HSP105 as well as HSC70 were localized in the cytoplasm and the nuclei of cells in various mouse embryonic tissues. After treatment of tissue sections with proteinase K, HSP105 but not HSC70 was also found to be localized in condensed cells and condensed bodies which showed the typical characteristics of apoptotic cells and apoptotic bodies at the interdigital regions of limbs. These findings suggest that HSP105 plays important roles during mouse embryo development.

Afferent mechanism of cortical myoclonus studied by proprioception-related SEPs

Proprioception-related somatosensory evoked potentials (SEPs) to passive flexion movement of the middle finger at proximal interphalangeal joint were recorded in 7 patients with myoclonus of cortical origin who demonstrated enlarged electrical SEPs (giant SEPs). In 3 out of the 7 patients, the proprioception-related SEPs were also enlarged. The remaining 4 patients showed giant electrical SEPs without enhancement of proprioception-related SEPs. Long loop electromyographic response was recorded during the resting condition in all of the 3 patients with enlarged proprioception-related SEPs. We have previously reported that proprioception-related SEPs are mainly generated by muscle afferent inputs, though electrical SEPs are thought to reflect mostly cutaneous inputs with some contribution from muscle afferents. Therefore, it is concluded that hyperexcitability of the sensorimotor cortex in cortical myoclonus is modality-specific. Cortical excitability is exaggerated to both cutaneous and deep receptor inputs in some patients, but only to cutaneous input in others.

[Jaw position, head position, body posture: development of an integrated system of examination, Part I]

Recently in the field of clinical orthodontics, there has been increased interest in the relationship between jaw and head position, sleep apnea, and equivocal symptoms occurring in head, neck and shoulder. It has already been determined that a relation exists between head posture and mode of breathing. Since the craniofacial skeleton is supported by the cervical, thoracic and lumbar vertebrae, the head position might have some biomechanical connection to total body posture. Therefore, an integrated system of examining jaw position, head position and body posture is being developed.

Immunohistochemical localization of pH-sensitive K+ channel, RACTK1

RACTK1 cDNA encodes a pH-sensitive K+ channel from the renal cortical collecting tubule cells, which is only localized in the kidney by Northern blots (Suzuki, M., K. Takahashi, M. Ikeda, H. Hayakawa, A. Ogawa, Y. Kawaguchi, and O. Sakai. Nature Lond. 367: 642-645, 1994). We further investigated the localization of the channel by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). Immunohistochemical analysis showed that the signal was detected in various epithelia, including the luminal membrane of the cortical collecting tubules, artery of the kidney, and pancreatic ducts. Interestingly, the signal was also detected in the coronary vascular smooth muscle and cerebral artery. These tissue distributions were confirmed by localization of mRNA determined by RT-PCR. These findings suggest that RACTK1 encoding pH-sensitive K+ channels is widely distributed in epithelia as well as in vascular smooth muscle cells.

Programmed cell death in the interdigital tissue of the fetal mouse limb is apoptosis with DNA fragmentation

BACKGROUND

Programmed cell death is an essential event during mammalian morphogenesis which eliminates unnecessary cells to accomplish histogenesis and organogenesis. Cell death in interdigital spaces of the developing limb is a classical example of morphogenetic cell death. We investigated whether classical programmed cell death in the interdigital tissue of the developing limb in mice is apoptosis with fragmentation of nuclear DNA and also examined sequentially the occurrence of programmed cell death and cell proliferation in the developing limb of mouse fetuses to analyze their interrelation.

METHODS

We examined the occurrence of apoptotic cell death in the developing limbs of mouse fetuses by using Nile blue sulphate staining, agarose gel electrophoresis for detecting DNA laddering, and a cytochemical labeling of DNA fragmentation. We also labeled proliferating cells using BrdU/anti-BrdU immunohistochemistry and examined the interrelation between apoptotic programmed cell death and cell proliferation.

RESULTS

DNA ladders, a biochemical evidence of apoptosis, were detected in DNA extracts from the interdigital tissue of day 13 mouse fetuses by agarose gel electrophoresis. Programmed cell death and DNA fragmentation were detected by Nile blue staining and cytochemical labeling of DNA fragmentation, respectively, in the interdigital mesoderm and in the regions of presumptive joints of the digit. BrdU/anti-BrdU immunohistochemistry for identifying proliferating S-phase cells revealed that interdigital mesenchymal cells cease DNA synthesis before programmed cell death and DNA fragmentation begin.

CONCLUSIONS

We confirmed that both cytological apoptotic alterations and fragmentation of nuclear DNA occur in the interdigital tissue and presumptive joint areas of fetal mouse limbs, and they appear to play a significant role in the separation of digits as well as the formation of joint cavities.

Antibodies against GM1 ganglioside affect K+ and Na+ currents in isolated rat myelinated nerve fibers

High titers of anti-GM1 ganglioside antibodies (anti-GM1 antibodies) may be implicated in lower motor neuron disease. We studied the pathogenic role of anti-GM1 antibody using the petroleum jelly-gap voltage clamp technique on isolated single myelinated rat nerve fibers. Anti-GM1 antisera were obtained from rabbits immunized with GM1 ganglioside. Extracellularly applied anti-GM1 antisera without complement activity increased both the rate of rise and the amplitude of the K+ current elicited by step depolarization, with little effect on Na+ current. In the presence of active complement, however, anti-GM1 antibodies decreased the Na+ current, and caused a progressive increase of nonspecific leakage current. Neither complement alone nor complement-supplemented antisera from which anti-GM1 antibodies were depleted by affinity chromatography had any effect on ionic current. These observations indicate that anti-GM1 antibodies themselves can uncover K+ channels in the paranodal region, while anti-GM1 antibodies bound to the nodal membrane in the presence of complement may form antibody-complement complexes that block Na+ channels and disrupt the membrane at the node of Ranvier.

An animal model of chronic ischemic neuropathy with proliferative changes of nerve microvessel wall

In order to produce a model of ischemic neuropathy with neural microvascular alterations, sodium laurate was injected into a femoral artery and saline into the contralateral artery at the mid-thigh level in Sprague-Dawley rats aged 11 weeks. In view of the dose-related findings, 0.3 mg sodium laurate dissolved in 0.1 ml saline was used for the main experiment. The laurate-injected leg showed paresis during the experimental period. On day 1-7, various stages of Wallerian degeneration and acute microvascular changes were found. At 1 month, regenerating myelinated nerve fibers (MNFs) were found at the central or total fascicular area mainly in the distal tibial nerve. Morphometric analyses suggested that MNFs other than regenerating fibers are atrophic ones. The proliferative changes of nutrient microvascular walls were striking. The percent of closed epineurial microvessels was significantly larger on the laurate-injected sides and inversely associated with the diameter of MNFs. At 7 months, the attenuation of MNFs was more prominent and microvascular alterations were persistently observed. These pathological findings resemble those of chronic ischemic neuropathy including diabetic neuropathy, suggesting that this neuropathy model might provide some valuable and useful clues for clarifying the pathogenesis of chronic ischemic neuropathy.

[Lifestyles related to preserving 20 or more teeth at 80 years of age]

To explore lifestyle factors related to preserving 20 or more teeth at 80 years of age, a total of 114 Japanese persons aged 80 years old (70 with 20 teeth or more (mean teeth: 25.0 +/- 2.8) and 44 with 19 teeth or less (mean teeth: 5.2 +/- 6.3)) were studied. Study subjects received a dental examination and were directly interviewed, using a questionnaire, to collect such information as past episodes of tooth and gingival conditions, past attitude to dental care and several lifestyle habits. The following major findings emerged by statistical analysis. Probability of preserving 20 or more teeth at 80 years of age was significantly high with: (1) strict upbringing in childhood (p < 0.05 in males), (2) no swollen gums around 60 years old (p < 0.01 in males), (3) early visit to a dentist around 40 years old (p < 0.05 in males), and (4) not being fond of sweets in childhood (p < 0.05 in females). The following related to a high tendency toward preserving 20 or more teeth at 80 years of age: (1) graduate from primary school only (in females), (2) having a home dentist around 20 years old (in males), (3) tended to visit a dentist earlier at 20 years old (in males), (4) not eating sweet things at 60 years old (in males), and (5) have not smoked cigarettes (in males).(ABSTRACT TRUNCATED AT 250 WORDS)

[Dimensional change and deformation on stone dies for full cast crowns. Differences according to impression methods using vinyl silicone impression materials]

In order to reconfirm the efficiency of an individual tooth tray, an apparatus and method were developed for measuring dimensional changes and observing over all deformation on a stone die for a full cast crown. The stone dies, which were made by combination impression methods I, II and double impression (individual tooth tray use) with vinyl silicone impression materials, were measured and compared. The results were as follows: 1. It made no difference what kind of vinyl silicone impression materials were used. 2. As to the dimensional changes: for combination impression method I, irregular results were found for the stone dies with the differences between +1 standard deviation (SD) and -1 SD being large. The variations of the other two methods were quite small, indicating that the stone dies were made accurately. 3. Observing to magnified images with the naked eye, there were no clear differences between the three methods on the marginal parts, but at the top corners of the stone dies there were good results with the double impression method. 4. It was possible to grasp easily the general aspect of dimensional changes in the stone dies using this newly developed measuring method.

Synergistic effect of dolichyl phosphate and human recombinant granulocyte colony-stimulating factor on recovery from neutropenia in mice treated with anti-cancer drugs

Severe hematopoietic injury in mice was induced by using either 5-fluorouracil, adriamycin, mitomycin C, or vinblastine. Daily subcutaneous administration of purified human recombinant granulocyte colony-stimulating factor (rG-CSF; 0.3-10.0 micrograms/day) markedly accelerated recovery from the drug-induced granulocytopenia in a dose-dependent manner, as reported previously. On the other hand, daily intraperitoneal administration of dolichyl phosphate (Dol-P) also enhanced granulopoiesis to accelerate recovery from granulocytopenia, although the effect of Dol-P was relatively moderate as compared with that of rG-CSF. A synergistic recovery of granulopoiesis was observed when Dol-P was administered together with rG-CSF to the mice treated with anti-cancer drugs. Joint use of Dol-P (1 mg/day) and rG-CSF (0.3 micrograms/day) was as effective as a higher dose of rG-CSF (3 micrograms/day). Joint use of Dol-P (1 mg/day) and rG-CSF (3 micrograms/day) was sometimes more effective.

Effectivity of dolichyl phosphates with different chain lengths as acceptors of nucleotide activated sugars

Chemical synthesis of different S-forms of dolichyl-P was performed in order to investigate the use of these polyprenes in mannosyl, glucosyl and glucosaminyl transferase reactions. Determination of the Vmax values for a series of dolichyl-P demonstrated that the velocities of transferase reactions with all those dolichyl-P derivatives present in animal tissues are largely the same. The apparent Km values for the various dolichyl-P in the transferase system studied differed, but this property does not appear to have physiological importance.