Previously we found that conditioning stimulation applied to the mesencephalic periaqueductal gray matter (PAG) inhibited the response of thalamic neurons to nociceptive input in the lateral and medial pain pathways. The inhibitory system arising from the PAG exerted inhibitory effects on a large proportion of thalamic nociceptive neurons in the lateral pain pathway, while only on a small proportion of thalamic nociceptive neurons in the medial pain pathway. In the present experiment, we studied the effect of conditioning stimulation applied to the fornix (Fx) on the response of nociceptive neurons in the intralaminar nuclei and in the nucleus ventralis posteromedialis (VPM). Experiments were carried out on adult cats anesthetized with urethane and chloralose. Single neuron activities were recorded from the nucleus centralis lateralis (CL), the nucleus parafascicularis (Pf) and the VPM. We studied the effect of conditioning Fx stimulation on neurons that respond to stimulation of the greater splanchnic nerve, greater occipital nerve, and/or tooth pulp. We obtained 43 CL and 38 Pf nociceptive neurons. They usually respond to heavy pressure applied to deep tissues rather than skin. In 13 CL and 11 Pf neurons, conditioning Fx stimulation at an intensity of less than 1mA inhibited the response to peripheral input and/or to electrical stimulation of the mesencephalic reticular formation (MRF). Intravenous naloxone (1mg/kg) did not antagonize inhibition of the response of nociceptive CL and Pf neurons to peripheral input and/or MRF stimulation. A total of 20 tooth pulp neurons that responded to tooth pulp afferent input were recorded from the shell region of the VPM. The response to tooth pulp stimulation or trigeminothalamic tract stimulation was not inhibited in any of them by the conditioning Fx stimulation. The results suggest that nociceptive neurons in the intralaminar nuclei are inhibited following conditioning stimulation of the Fx, and that this inhibition is not mediated by opiate receptors. This inhibitory system arising from the Fx acts mainly at the thalamic level of the medial pain pathway.

View full abstract

We used the poly T probe in rat intestinum tenue tissues to elucidate optimal conditions for the rapid in situ hybridization (ISH) method. Following fixation in either 20% neutral buffered formalin solution or Mildform 20 N, the tissues were immersed in either 10% EDTA or K-CX for 1, 6 or 12 days. All laboratory materials including glassware and reagents were treated with diethyl pyrocarbonate. We found when rapid ISH is applied, that 1) tissue fixed with Mildform 20 N should not be immersed in the decalcifying solution. 2) A 10% EDTA solution should be used as the decalcifying solution, and the shorter the decalcification time, the better. 3) When K-CX solution is used, the specimen should be cut into peices as small as possible and immersed in the solution within one day. These results indicate that the rapid ISH method is very effective when used under optimal conditions for the immersion time in the fixative and decalcifying solutions.

View full abstract

Previous studies have shown that exopolysaccharide (EPS) from Prevotella intermedia is related to the invasiveness of bacteria. In this study, we attempted to purify EPS derived from Prevotella nigrescens strains 22 and 23, and compared these EPSs with that from P. intermedia. We also isolated an EPS^- strain (designated as strain 328) from the EPS^+ strain (strain 22) by treatment with ethidium bromide, and examined the geno- and phenotypic characteristics of these strains. Purified EPSs were primarily neutral sugar consisting of mannose as a major component. Both EPSs contained glucose, galactose, arabinose and xylose. Fructose (15.8μg/mg) was detected in EPS from strain 22, but not in that from strain 23. The ratio of mannose to glucose was greater in the EPSs from P. nigrescens strains 22 (20:1) and 23 (25:1) than in that from the P. intermedia strain 17 (5:1). The plasmid bands and enzymatic activities were the same for both strains 22 and 328, suggeesting that the gene controlling the production of EPS was not on these plasmids. We were unable to detect phage particles after irradiation with ultraviolet light. We also failed to detect differences in the restriction fragment length when we performed polymorphism analysis of the chromosomal DNA of both strains using Not I and Bgl I. Therefore, we examined the phenotypic characteristics and did SDS-PAGE analysis. Scanning electron microscopy revealed net-like structures around the cells of strain 22, but not around those of strain 328.This supports the results of Nakatani et al. The hemagglutinating activity of strain 328 was greater, indicating that EPS tends to interfere with hemagglutination rather than mediate it. Although other characteristics of the two strains, such as carbohydrate fermentation, enzyme production and hemolysis, were quite similar, the SDS-PAGE patterns revealed that strain 328 lacks the 52kDa protein. These results coloectively suggest that this 52kDa protein may control the production of EPS.

View full abstract

We evaluated the dentofacial morphology of patients with unilateral cleft lip and palate after puberty. Coben analysis was done using lateral cephalograms obtained at the initial consultation for 30 patients with unilateral cleft lip and palate accompanied by reversed occlusion in the anterior teeth (males aged ≧ 19 years and older, females aged ≧ 18 years and older, at Hellman developmental stage VA). Thirty patients without cleft lip and palate showing normal occlusion in the anterior teeth, and 30 without cleft lip and palate showing reversed occlusion in the anterior teeth were similarly analyzed as controls. Principal component analysis of variables was performed for each subject. Compared with the normal occlusion group, these with cleft lip and palate group showed no significant differrence in either depth of the inferior face of height of the posterior face. They also had an increased anterior slope of the mandibular ramus and mandibular angle, plus increased lower anterior dental height, and displayed shortened anteroposterior dimension of the middle face. Compared with the reversed occlusion group, the cleft lip and palate group showed a shorter depth of the inferior face, had shorter anteroposterior dimension of the middle face, and displayed no significant differrence in the anterior slope of the mandibular ramus, the mandibular angle, height of the posterior face or the lower anterior dental height.

View full abstract