Origins and conducting pathways of motor evoked potentials elicited by transcranial (vertex-hard palate) stimulation in cats.

Spinal cord evoked potentials were elicited in cats by transcranial electrical stimulation with electrodes on the vertex and hard palate. Vertex motor evoked potentials (V-MEP) were also recorded. An extracellular microelectrode recording technique was then used to analyze the results by isopotential mapping. The relationship between the distribution of field potentials and the stimulation polarity was studied using the field potential distribution of the V-MEP in the lower thoracic spinal cord that had been represented on the isopotential maps. The first negative wave of the V-MEP showed maximal amplitude distribution in the anterior funiculus, which corresponds to the extrapyramidal tracts. This pattern was seen with both stimulation polarity arrangements: 1) stimulation with the cathode at the vertex and the anode at the hard palate, and 2) stimulation with the anode at the vertex and the cathode at the hard palate. When the cathode was at the vertex, the stimulation threshold was lower, and the response had higher amplitude than when the anode was at the vertex. Recording V-MEPs elicited by vertex cathode stimulation could provide an excellent method of monitoring the extrapyramidal tracts in cats.

Radiographic classification of Os odontoideum and its clinical significance.

STUDY DESIGN: This study analyzed the relationship between the configuration of the atlantoaxial joint and the clinical characteristics of patients with os odontoideum. OBJECTIVES: To compare three types of atlantoaxial configurations of os odontoideum from the viewpoint of clinical characteristics. METHODS: Twelve patients were classified into the following three types according to their atlantoaxial configuration on an anteroposterior radiogram: round (n = 6), cone (n = 4), and blunt-tooth (n = 2). Clinical features in each group were compared in terms of mean age, gender distribution, severity and type of myelopathy, and degenerative findings of the atlantoaxial joint. RESULTS: The patients in the round type group were predominantly women and had more severe myelopathy than that of patients in the other groups. According to Crandall's classification of myelopathy, all patients showed the transverse lesion syndrome in the cone and blunt-tooth types. Four of six patients with the round type of atlantoaxial configuration had the Brown-Séquard syndrome. With the round type, it appeared that the lateral mass of the axis tended to dislocate laterally, and this lateral instability associated with anteroposterior instability was believed to induced the Brown-Séquard syndrome. CONCLUSIONS: Myelopathy in patients in the round type group was the most severe compared with that of patients in the other three groups. This classification is considered useful for estimating clinical findings in os odontoideum.

Blends of aliphatic polyesters. VI. Lipase-catalyzed hydrolysis and visualized phase structure of biodegradable blends from poly(epsilon-caprolactone) and poly(L-lactide).

Phase-separated biodegradable polymer blends were prepared from poly(epsilon-caprolactone) (PCL) and poly(L-lactide) (PLLA), and Rhizopus arrhizus lipase-catalyzed hydrolysis and phase structure of the blend films were investigated. Gravimetry revealed that the lipase-catalyzed hydrolysis of PCL in PCL- and PLLA-rich phases is disturbed by the presence of PLLA. Polarimetry confirmed the occurrence of a predominant hydrolysis of PCL and subsequent removal of the hydrolyzed water-soluble PCL oligomers in the blend films. Gravimetry and gel permeation chromatography of the non-blended PLLA film indicated that R. arrhizus lipase has no catalytic effect on the hydrolysis of PLLA. The phase structure of the blend films could be visualized by selective enzymatic removal of one component and subsequent scanning electron microscopic observation.

Emergence of permanent teeth and onset of dental stages in Japanese children.

The purpose of the present cross-sectional study was to provide mean times of emergence of permanent teeth and onset of dental stages in Japanese children. A total of 1819 schoolchildren aged 6-15 yr were recorded. The results demonstrated specific sequences of emergence in the two arches and earlier emergence times in girls than in boys, both findings in keeping with investigations on other ethnic groups. Secular trend in tooth emergence was studied by comparing the results with data on Japanese children in 1934. The comparison revealed earlier mean times of emergence in general in contemporary Japanese.

Solitary osteochondroma of the mandibular symphysis.

Osteochondroma is a benign neoplasm that usually develops in long bones and very rarely occurs in craniofacial bones. Nearly all reported mandibular osteochondromas have arisen in the condyle and the coronoid process, and occurrence in other locations is extremely rare. We describe a case of osteochondroma arising from the inferior border of the mandibular symphysis.

Enhanced surfaces for endothelial cell seeding.

Silver negative ions (Ag-) were implanted to polystyrene (PS) and tissue culture polystyrene (TCPS) by using neutral and ionized alkaline bombardment-type heavy negative ion sources, NIABNIS. Surface property and biocompatibility of Ag(-)-implanted TCPS and PS were investigated. Enhanced growth of vascular endothelial cells was observed on Ag(-)-implanted TCPS at a dose of 10(16) ions.cm-2 at an ion energy of 10 keV and Ag(-)-implanted (at ca. 10(15) ions.cm-2 dose and 10 keV energy) PS region. As a result of Ag(-)-implantation, PS and TCPS surfaces were considered to be more hydrophobic and to be more hydrophilic, respectively.

Fundamental characteristics of human limb electrical impedance for biodynamic analysis.

The paper describes the use of human-limb impedance for biodynamic analysis. The change of human-limb impedance during movement was measured, and was found to be related to kinematic and kinetic parameters. Strong relationships were found between the velocity of change of the forearm impedance and the angular velocity of the elbow joint (correlation coefficient r = -0.97), between the the change of forearm impedance and the velocity of a human limb (r = 0.79). A change of upper-limb impedance was caused by a change in a sectional area of muscular tissue in the measured part and a change of blood volume during movement of an upper limb. In tennis, there was a strong relationship between a change of forearm impedance and ball velocity (r = 0.87). Impedance waveforms were useful for analysis of the movement pattern and the stability of movement in tennis. This method has the following characteristics: (a) it does not have a spatial and temporal limitation for measurement; (b) the subject is scarcely restricted in movement; (c) the data processing can be handled easily and quickly; (d) impedance waveforms inherently show magnitude, form and stability of movement.

[Resection and reconstruction of full thickness chest wall].

Nine patients underwent full thickness chest wall resection and reconstruction in our department between January 1981 and December 1994. There were chest wall recurrence of breast cancer in 5 cases, primary chest wall chondrosarcoma in 2, primary chest wall malignant fibrous histiocytoma in 1 and metastatic sternal renal cell carcinoma in 1. Seven of 9 cases underwent partial sternal resection. Sizes of chest wall defects were from 10 x 7 cm to 15 x 14 cm. In eight cases of 9, chest wall reconstruction was by double Marlex mesh repairs and various flaps (major pectoral muscle in 3, major pectoral myocutaneous flap in 2, latissimus dorsi myocutaneous flap in 1 and pedicled omentum in 1). The last case underwent repair with rectus abdominis myocutaneous flap without mesh. There was no operative death. Postoperative complications occurred in 4 patients: partial skin necrosis in 2, skin dehiscence in 1 and respiratory failure in 1. Eight cases are alive now from 9 months to 14 years and 8 months after chest wall reconstruction. One patient with metastatic renal cell carcinoma died of recurrence 3 years after operation. Full thickness chest wall resection and reconstruction is a safe operation and may provide a long-term survival.

[A case of adenoid cystic carcinoma of the trachea resected surgically after Nd-YAG laser therapy].

A case of primary tracheal tumor ablated by endoscopic Nd-YAG laser prior to tracheal sleeve resection was reported. A 53-year-old man had dry cough, bloody sputum and dyspnea. Bronchoscopic examination revealed polypoid tumor which located 2 cm below the vocal cords and obstructed the airway almost completely. After tumor vaporized by Nd-YAG laser, bronchoscopy type 200 could pass through the tracheal lumen and the length of the lesion was diagnosed within 4 cm. Biopsy specimen was confirmed adenoid cystic carcinoma. Cervical trachea was resected of six tracheal cartilage (first to sixth cartilage) combined with left thyroid lobe under collar incision and median sternotomy. The neck was fixed for ten days by tying the jaw to the anterior chest wall in order to reduce excessive tension to the anastomosis. Pathological examination revealed the tumor residual microscopically, 60 Gy of radiotherapy was conducted.

[Treatment of Yusho patients with cholestyramine].

Six typical Yusho patients (3 men, 48-58 years old, and 3 women, 45-55 years old) were treated with cholestyramine, 8-12 g/day, for 24 weeks. Improvement of some symptoms, such as arthralgia and malaise, was observed in 2 men, although this effect was non-specific. None of the patients showed increment of excretion of polychlorinated biphenyl or polychlorodibenzofuran into feces.

[Effects of treatment with rice bran fiber and cholestyramine on clinical and laboratory findings in Yusho patients].

To investigate the therapeutic effects of rice bran fiber (30 g/day) and cholestyramine (12 g/day) for Yusho, clinical signs and symptoms, and laboratory examinations were studied before, during and after 14 day-treatment in four patients with Yusho. The increases of bowel movements and abdominal distention were observed in two of these patients, although no effect was seen in physical findings. In peripheral blood cells, red blood cell counts decreased significantly, from 430 +/- 47 x 10(4)/mm3 (mean +/- SD) to 378 +/- 48 x 10(4)/mm3 (p < 0.01) after therapy. Hemoglobin as well as hematocrit levels were also reduced significantly afer the therapy. However, no significant effect of the treatment was observed in white blood cell counts or platelet counts. In biochemical parameters, a significant depression was observed in total cholesterol levels after the therapy (from 262 +/- 31 mg/dl to 179 +/- 33 mg/dl; p < 0.005). A significant elevations was observed in serum levels of alanine aminotransferase and sodium, while significant depressions were found in serum levels of cholinesterase, total protein, albumin, gamma-globulin, and potassium.

[Effects of rice bran fiber and cholestyramine on peripheral blood cells and biochemical parameters in Yusho].

To investigate clinical effects of rice bran fiber and cholestyramine therapy in Yusho, peripheral blood cells and biochemical parameters were studied before and after therapy in eleven healthy volunteers and four patients with Yusho who were treated with rice bran fiber 30 g/day and cholestyramine 12 g/day for 7 days. In healthy volunteers, a significant elevation in total leukocyte counts as well as lymphocyte counts was observed after therapy (leukocyte p less than 0.005, and lymphocyte, p less than 0.01). In lymphocyte subpopulations, significant elevations were found in CD3- and B1-positive cells (CD3, p less than 0.05 and B1, p less than 0.001). However, no significant effect of the treatment was observed in reticulocyte counts or platelet counts. In biochemical parameters, total cholesterol levels decreased significantly, from 208 +/- 36 mg/dl (mean +/- SD) to 173 +/- 30 mg/dl (p less than 0.001), after therapy. HDL-cholesterol levels were also reduced significantly after therapy (from 50 +/- 12 to 46 +/- 13/mg/dl; p less than 0.05). Serum triglyceride levels increased significantly, from 155 +/- 96 to 195 +/- 133 mg/dl (p less than 0.05), after therapy. A significant increase was observed in serum levels of alanine aminotransferase, while significant depressions were found in serum levels of total bilirubin, total protein, gamma-globulin, creatinine, and calcium. In four Yusho patients who received rice bran fiber and cholestyramine therapy twice with more than one month interval, the clinical effects of therapy in addition to biochemical effects were studied. An only significant effect was observed in serum levels of total cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

[Therapeutic trials for promotion of faecal excretion of PCDFs by the administration of rice bran fiber and cholestyramine in Yusho patients].

It is well-known that Yusho disease was caused by polychlorinated dibenzofurans (PCDFs), and that 2, 3, 4, 7, 8-Pentachlorodibenzofuran (PnCDF), 1, 2, 3, 4, 7, 8- and 1, 2, 3, 6, 7, 8-Hexachlorodibenzofurans (HxCDFs) still retain in the patient bodies. As patients usually suffer from various chronic syndrome, an effective treatment is extremely needed. In order to assess the rice bran fiber (RBF) and cholestyramine on stimulating faecal excretion of PCDFs, two clinical trials were carried out in 1990 and 1991. In the first trial in 1990, 10 g of RBF (dietary fiber content was 50%) and 4 g of cholestyramine were administered to four Yusho patients three times a day for a week. The stool from patients were collected a week before and during the administration. These were pooled respectively, and then two samples for measurement. In the second trial in 1991, 10 g of dietary fiber rich RBF (refined-RBF, dietary fiber content was 85%) and 4 g of cholestyramine were administered to four Yusho patients three times a day for two weeks. In this trial, three stool samples were obtained from each patient, ie., a week before administration, and first and second week during administration. Level of PCDFs was determined by high resorption GC/MS and the following results were obtained. 1) In the first trial (1990) the faecal excretion of PnCDF and HxCDFs increased at the rates of 42-88% and 7-47%, respectively, in three out of four patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Dentin resorption and cementum-like tissue formation by bone morphogenetic protein application.

BACKGROUND AND OBJECTIVE: Recent studies have shown that bone morphogenetic protein-2 (BMP-2) stimulates mineralization and osteoclast differentiation. Osteoclastic resorption by BMP-2 application may play an important role in the regulation of new cementum-like tissue formation on the dentin surfaces. Therefore, this study aimed to examine the effect of BMP-2 application on dentin resorption and cementum-like tissue formation at the dentin surfaces. MATERIAL AND METHODS: Seventy-two flat dentin blocks were prepared from rat roots and treated with 24% EDTA. Each block was assigned to group 0, group 100, or group 400, and immersed correspondingly in 0, 100, or 400 microg/ml BMP-2. The dentin blocks were then implanted into palatal connective tissue of rats, and specimens were prepared 2, 4 and 8 wk after surgery for histologic and histomorphometric analyses. RESULTS: BMP-2 caused a dose-dependent increase in dentin resorption by osteoclastic cells. New cementum-like tissue was randomly formed on parts of the nonresorbed and resorbed dentin surfaces in groups 100 and 400. Dentin resorption in groups 100 and 400 was significantly greater than group 0 (p < 0.01). However, at 8 wk, new cementum-like tissue formed in 41.8% of group 100, as compared with 16.2% of group 400 (p < 0.05). CONCLUSION: Dentin resorption was stimulated by a high dose of BMP-2, and cementum-like tissue was induced by a low dose of BMP-2, effectively suggesting that BMP-2 application, at an appropriate dose, to a dentin surface may enhance periodontal regeneration.

Enzymatic hydrolysis of poly(lactide)s: effects of molecular weight, L-lactide content, and enantiomeric and diastereoisomeric polymer blending.

Nonblended poly(L-lactide) (PLLA) films having different molecular weights and nonblended poly(lactide) (PLA) films, enantiomeric blend films from PLLA and poly(D-lactide) (PDLA), and diastereoisomeric blend films of poly(DL-lactide) (PDLLA) with either PLLA or PDLA, having different L-lactide (LLA) contents (X(LLA)s) in the range of 0-0.99, were amorphous made by melt-quenching. The effects of molecular weight, X(LLA), and average L- and D-lactyl unit sequence length (l(L) and l(D), respectively) on the enzymatic hydrolysis of the films were investigated in the presence of proteinase K. The enzymatic hydrolysis rate (R(EH)) of PLLA estimated by gravimetry increased monotonically with the inverse of number-average molecular weight (M(n)). The extrapolation of R(EH) of PLLA to M(n)(-1) = 0, where no exo-chain-scission takes place, gave a positive R(EH) value (1.75 microg/(mm(2).h)), meaning that the enzymatic hydrolysis of PLLA proceeds via both endo- and exo-chain-scission. The R(EH) of the nonblended films as well as the enantiomeric and diastereoisomeric blend films decreased monotonically with the decease in X(LLA) and finally became zero for X(LLA) below 0.3. The R(EH) values of the blend films of PLLA and PDLLA with PDLA (l(D) = infinity) were lower than expected, while the R(EH) values of the blend films of PLLA with PDLLA (l(D) = 4) agreed completely with the expected values. These results reveal that the nonblended PLA films are enzymatically hydrolyzable when X(LLA) and l(L) are higher than 0.3 and 3, respectively, and l(D) is lower than 10 and that the presence of long D-lactyl unit sequences (l(D) > 4) as in PDLA hinders the enzymatic hydrolysis of long L-lactyl unit sequences even when long D- and L-lactyl unit sequences are present in the different molecules.

Targeting of liposomes surface-modified with glycyrrhizin to the liver. I. Preparation and biological disposition.

We consider glycyrrhizin to be a new ligand for liposomes to the liver because it is known that about 80% of glycyrrhizin is excreted into the bile after intravenous administration in rats. In order to modify the liposomal surface with glycyrrhizin, 30-stearyl glycyrrhizin (GLOSt), one of the lipophilic glycyrrhizin derivatives, was synthesized. The structure of this new compound was identified by nuclear magnetic resonance (NMR), infrared (IR) and mass spectra (MS). Sonicated liposomes were prepared from hydrogenated egg phosphatidylcholine-cholesterol-GLOSt or dicetyl phosphate (DCP) (4:4:1) and were labelled with [3H]inulin as an aqueous marker. It was confirmed by measuring the encapsulation efficiencies and the mean diameters that GLOSt-containing sonicated liposomes (GLOSt-SUV) were SUV-type as well as DCP-containing control liposomes (control-SUV). Four hours after intravenous injection into rats at a dose of 90 mumol as total lipid per kg of rat body weight, GLOSt-SUV showed 4-fold more accumulation (42.4%) in the liver than control-SUV. Therefore, glycyrrhizin is considered to be a useful new ligand on liposomes for targeting to the liver.

Uptake of liposomes surface-modified with glycyrrhizin by primary cultured rat hepatocytes.

Previously, we synthesized 30-stearyl glycyrrhizin (GLOSt) and reported that small unilamellar liposomes containing GLOSt (GLOSt-SUV) accumulated in the liver several times more than the control liposomes (control-SUV). In the present study, to determine the interaction between GLOSt-SUV and hepatocytes, in vitro uptake experiments were achieved with primary cultured rat hepatocytes. The uptake amount of GLOSt-SUV by rat hepatocytes was considerably higher compared to the control-SUV, while GLOSt-SUV showed about a 10-fold higher uptake level than the control-SUV during 2 h of incubation. It was assumed that GLOSt-SUV not only bind to the surface of the hepatocytes but are internalized and degraded in the cells, because at 37 degrees C, GLOSt-SUV were taken up and the level of the degradable marker was lower than the inert marker, and this did not occur at 4 degrees C. Since the uptake of GLOSt-SUV was inhibited by glycyrrhizin (GL), it was suggested that a binding-site for GL is present on the surface of hepatocytes, and GLOSt-SUV are likely to be internalized via this site by the hepatocytes. Furthermore, it was confirmed that the efficacy of GLOSt on liposomes is not affected by the fluidity of the liposomal membrane.

Production of thrombi on intact endothelium by use of antiheparin agents in vivo.

It had been suggested that antithrombin activity on the surface of intact endothelial cells may play a role in inhibiting platelet adhesion and thrombus formation. The antithrombin activity may be due to thrombomodulin or to activation of antithrombin III by glycosaminoglycans or thrombomodulin, or possibly a combination of these. This inhibitory activity has been shown to be affected by such antiheparin agents as protamine, hexadimethrine bromide (Polybrene; Aldrich Chemical Co., Milwaukee, Wis.) and platelet factor 4, as well as by such enzymes as heparinase and heparitinase. We have used a hamster cheek pouch preparation to observe thrombus formation in vivo in a normal vascular flow, to determine whether the production of thrombi by thrombin can be enhanced by antiheparin agents. After intra-arterial injection or topical application of protamine or hexadimethrine bromide, platelet adhesion and thrombus formation on intact arteriolar endothelium was produced by a dose of thrombin, which when injected alone had no effect. No thrombi were found in venules or capillaries. Injection of heparin before or after the antiheparin agents necessitated a larger dose to enhance the action of thrombin. On electron microscopy the thrombi were found to consist primarily of platelets adherent to an intact endothelium. The possible clinical implications of these observations are discussed.

Anterior interbody fusion with and without interspinous block implementation for lumbar isthmic spondylolisthesis.

The clinical and radiographic results of lumbar isthmic spondylolisthesis were compared between interspinous block-assisted anterior interbody fusion (block-assist group, n = 16) and anterior interbody fusion with no use of the block (nonassist group, n = 17) with an average follow-up of 7 years (range 1 1/3-13 years). Satisfactory relief of low-back pain, significantly early interbody union (union rate 88%, p < 0.05), and spontaneous fusion of pars defect (fusion rate 44%, p < 0.05) were obtained in the block-assist group. In the nonassist group, interbody union was markedly delayed (p < 0.05), the union rate was 53%, and spontaneous fusion of the pars was found in 12% of patients. The overall clinical results at final follow-up in both groups did not show a statistically significant difference, but the results tended to be superior in the block-assist group.