The thickness of the roof of the glenoid fossa in the temporomandibular joint: relationship to the MRI findings

OBJECTIVES

The purpose of this study was to clarify the relationship between the thickness of the roof of the glenoid fossa (RGF) and magnetic resonance imaging (MRI) findings of temporomandibular joint (TMJ) disorders (TMDs).

METHODS

Eighty-seven patients with symptoms and indications of TMD in one or both TMJs were referred for MRI. Cone-beam CT (3DX) was used to measure the thickness of the RGF at its thinnest point. Linear measurements were made three times on the monitor by three separate investigators and the mean values obtained were used for the statistical analyses.

RESULTS

The joints were categorised as normal (70 joints), anterior disc displacement with reduction (ADWR; 53 joints) or anterior disc displacement without reduction (ADWOR; 51 joints). The joint disorders were also categorised into the following subgroups: with osteoarthritis (OA) (21 joints), without OA (153 joints), with disc deformation (33 joints), without disc deformation (141 joints), with joint effusion (JE) (61 joints) and without JE (113 joints). The average minimum thickness of the RGF was 0.85 mm for normal joints, 0.90 mm with ADWR, 0.93 mm with ADWOR, 0.99 mm with OA, 0.87 mm without OA, 0.87 mm with disc deformation and 0.89 mm without disc deformation. There was no significant difference between these figures. There was a significant difference in the thickness of the RGF with (0.97 mm) and without (0.84 mm) JE.

CONCLUSIONS

These results suggest that RGF thickness is influenced by JE, but is unaffected by disc position and configuration.

Gas phase detection of cyclic B3: 2 2E′←X 2A1′ electronic origin band

The rotationally resolved origin band in the 2(2)E'<--X2A1' electronic spectrum of cyclic B3 has been observed by cavity ring down spectroscopy in the gas phase. The B3 molecule was generated in a supersonic planar plasma containing decaborane (B10H14) and neon as a carrier gas. The rotational structure pattern is that of a cyclic molecule. It is analyzed assuming an equilateral triangle in both electronic states. The band origin is determined to be 21 853.52 cm(-1), and the bond lengths 1.603 77(106) A in the ground and 1.619 07(96) A in the excited electronic state are inferred from analysis of the rotational structure.

Genetic diversity of nuclear and mitochondrial genomes in Pinus parviflora Sieb. & Zucc. (Pinaceae) populations

Genetic diversities of the nuclear and mitochondrial genomes in Pinus parviflora were studied in 16 populations, which were distributed across most of the species' range in Japan. Six mitochondrial DNA haplotypes were identified among the 16 populations. The intrapopulation diversity of allozymes was similar to that of other endemic woody species (H(S)=0.259). Although P. parviflora is distributed in discrete populations, differentiation between these was very low (G(ST)=0.044). In addition, the extent of genetic differentiation between two varieties (var. pentaphylla and var. parviflora) was extremely low (G(VT)=0.001). Intrapopulation diversity of mitochondrial DNA was also very low (H(S)=0.098), but population differentiation was high (G(ST)=0.863). Moreover, the distribution of haplotypes reflected the taxonomic differences between P. parviflora var. pentaphylla and var. parviflora. The populations of var. pentaphylla and var. parviflora contained different haplotypes. Differing modes of inheritance may account for the differences in nuclear and mitochondrial genetic diversity.

Expression mechanism of the allosteric interactions in a ribozyme catalysis

The contribution of substrate binding to cooperative regulation in the rate process of ribozyme catalysis has been investigated using allosteric ribozymes. The high sensitivity to the substrate lengths is attributed to the catalytic core folding which proceeds due to the energetic contribution of the substrate binding. One role of the effector (FMN) is the promotion of the core folding through the stabilization of the aptamer domain. Another role is the inhibition of the cleavage chemistry by perturbing the intermediate state in the rate process. The total effects of these two types of kinetic regulation determine the substrate dependency of the cooperative interaction on the catalytic reaction. An adequate correlation between the type of regulation and the substrate binding is responsible for the cooperative interaction in the kinetic process.

Direct chemically mediated synaptic transmission from mechanosensory afferents contributes to habituation of crayfish lateral giant escape reaction

The neural mechanism of habituation of the crayfish lateral giant-mediated escape reaction was analyzed electrophysiologically and pharmacologically. Upon repeated stimulation of tailfan afferents (at 0.2-1 Hz) lateral giant showed rapid habituation and failed to spike. Upon low-intensity sensory stimulation, the lateral giant responded with two subthreshold excitatory post-synaptic potentials, the alpha and beta components. A third component, the alpha' component, was discriminated at the boundary of excitatory post-synaptic potentials between the late alpha and early beta components with stimulation just subthreshold or suprathreshold to evoke lateral giant spikes. This alpha' component increased in amplitude with hyperpolarizing current injected into the lateral giants, although the amplitude of both the alpha and beta components remained constant. Furthermore, bath application of the nicotinic antagonist, d-tubocurarine caused a rapid reduction in the amplitude of the alpha' component while the amplitude of the beta component was reduced gradually and that of the alpha component remained unchanged. Single-hair stimulation indicated that some sensory afferents made direct connections with the lateral giants mediated by chemical synapses and form the potential of alpha' component of the lateral giants. Since lateral giant inactivation was associated with a reduction of excitatory post-synaptic potential amplitude of the alpha' component, connection from these afferents could contribute, at least in part, to lateral giant habituation.

Enhancement of mitochondrial oxidative stress and up-regulation of antioxidant protein peroxiredoxin III/SP-22 in the mitochondria of human pre-eclamptic placentae

A growing body of evidence indicates that the pathogenesis of pre-eclampsia is closely associated with oxidative stress occurring in mitochondria. In the present study, we evaluated the degree of mitochondrial lipid peroxidation by assessing the accumulation of 4-hydroxy-2-nonenal (HNE)-modified proteins and examined the expression of mitochondrial antioxidant protein peroxiredoxin III/SP-22 in normal and pre-eclamptic human placentae. The accumulation of HNE-modified proteins increased to a greater extent in both the mitochondria and cytosol of pre-eclamptic placentae than in those of normal placentae. Moreover, the accumulation of HNE-modified proteins was much more evident in the mitochondria than in the cytosol, indicating that lipid peroxidation occurred mainly in the mitochondria of pre-eclamptic placentae. The mRNA expression of peroxiredoxin III/SP-22 was increased about 2-fold in pre-eclamptic placentae compared to normal placentae. The protein levels of peroxiredoxin III/SP-22 were approximately 4-fold higher in pre-eclamptic placentae than in normal placentae. Immunohistochemistry of placental tissues showed that the levels of peroxiredoxin III/SP-22 protein were increased in the trophoblasts of floating villi, stromal cells of stem villi, and decidual cells in pre-eclamptic placentae. These results indicate that peroxiredoxin III/SP-22 plays a crucial role in the protection of placental function from oxidative stress occurring in mitochondria of pre-eclamptic placentae.

Computed tomography of odontogenic myxoma

OBJECTIVES

The purpose of this study was to clarify the CT features of odontogenic myxoma.

METHODS

CT appearances were analysed in 17 patients with histologically verified odontogenic myxoma collected from five dental hospitals in Japan.

RESULTS

On the CT images, tumour borders were generally well defined with a smooth margin both for bony and soft tissue structures in all patients. Cortical status was clearly evaluated using CT and the continuity was interrupted in nine patients. Intralesional trabeculations were observed in 13 patients. Of these 13, 6 patients showed the characteristic appearance of angular or straight trabeculations within the tumour. The trabeculations were frequently observed at the peripheral portion of the tumour. In three maxillary tumours, soft tissue margins were observed beyond the cortical margin and/or intralesional trabeculations. In 10 of the 13 lesions evaluated, the majority of the whole tumour area showed relatively lower density compared with surrounding muscles.

CONCLUSION

CT clearly demonstrated characteristic features of odontogenic myxoma. CT analysis may contribute to establishing a consensus regarding the interpretation of conventional radiographic appearances in odontogenic myxoma.

Lateral giant fibre activation of exopodite motor neurones in the crayfish tailfan

The uropods of decapod crustaceans play a major role in the production of thrust during escape swimming. Here we analyse the output connections of a pair of giant interneurones, that mediate and co-ordinate swimming tail flips, on motor neurones that control the exopodite muscles of the uropods. The lateral giants make short latency output connections with phasic uropod motor neurones, including the productor, the lateral abductor and adductor exopodite motor neurones that we have identified both physiologically and anatomically. On the other hand, tonic motor neurones, including the ventral abductor and reductor exopodite motor neurones, receive no input from the lateral giants. We show that there is no simple reciprocal activation of the phasic opener (lateral abductor) and closer (adductor) motor neurones of the exopodite, but instead both phasic motor neurones are activated in parallel with the productor motor neurone during a tail flip. Our results show that the neuronal pathways activating the tonic and phasic motor neurones of the exopodite are apparently independent, with phasic motor neurones being activated during escape movements and tonic motor neurones being activated during slow postural movements.

A case of Korsakoff's syndrome improved by high doses of donepezil

We present a case of Korsakoff's syndrome that was successfully treated with high doses of donepezil, an inhibitor of acetylcholine esterase, known to retard the progress of symptoms in Alzheimer's disease. The patient was a 46-year-old married Japanese woman who began to drink alcohol after she married. After several years of drinking she developed typical symptoms of the Korsakoff syndrome. Donepezil was started after treatment with thiamine or thiamine plus fluvoxamine had failed. Her amnestic symptoms as well as her quality of life improved markedly during donepezil treatment. Inhibition of acetylcholine esterase may be an effective treatment for Korsakoff's syndrome.

Coupling between substrate binding and allosteric regulation in ribozyme catalysis

The contribution of substrate binding to allosteric regulation in the ribozyme catalysis has been investigated using allosteric ribozymes consisting of the hammerhead ribozyme and a flavin mononucleotide (FMN) aptamer. Kinetic parameters were measured for various lengths of the substrates with a wide range of binding energy. The maximum cleavage rate of each ribozyme was retained with the long substrates. However, the cleavage rates largely decreased by the truncation of the substrates according to loss in the free energy of substrate binding. The high sensitivity to the substrate lengths is attributed to the increase in the energetic requirement for the catalytic core folding, which is caused by the incorporation of the aptamer region. One role of FMN binding is assisting the promotion of the core folding through the stabilization of the aptamer domain. The allosteric effect is significantly expressed only when the substrate binding energy is insufficient for the core folding of the ribozyme-substrate complex. This type of allosteric interaction dominates the substrate dependency of another type of regulation. These results demonstrate that an adequate correlation between the type of regulation and the substrate binding is responsible for the effective allosteric interaction in the kinetic process.

Tumor suppressor PTEN: modulator of cell signaling, growth, migration and apoptosis

PTEN (also known as MMAC-1 or TEP-1) is one of the most frequently mutated tumor suppressors in human cancer. It is also essential for embryonic development. PTEN functions primarily as a lipid phosphatase to regulate crucial signal transduction pathways; a key target is phosphatidylinositol 3,4,5-trisphosphate. In addition, it displays weak tyrosine phosphatase activity, which may downmodulate signaling pathways that involve focal adhesion kinase (FAK) or Shc. Levels of PTEN are regulated in embryos and adult organisms, and gene-targeting studies demonstrate that it has a crucial role in normal development. Functions for PTEN have been identified in the regulation of many normal cell processes, including growth, adhesion, migration, invasion and apoptosis. PTEN appears to play particularly important roles in regulating anoikis (apoptosis of cells after loss of contact with extracellular matrix) and cell migration. Gene targeting and transient expression studies have provided insight into the specific signaling pathways that regulate these processes. Characterization of the diverse signaling networks modulated by PTEN, as well as the regulation of PTEN concentration, enzymatic activity, and coordination with other phosphatases, should provide intriguing new insight into the biology of normal and malignant cells.

Centrosome protein centrin 2/caltractin 1 is part of the xeroderma pigmentosum group C complex that initiates global genome nucleotide excision repair

Nucleotide excision repair (NER) is carried out by xeroderma pigmentosum (XP) factors. Before the excision reaction, DNA damage is recognized by a complex originally thought to contain the XP group C responsible gene product (XPC) and the human homologue of Rad23 B (HR23B). Here, we show that centrin 2/caltractin 1 (CEN2) is also a component of the XPC repair complex. We demonstrate that nearly all XPC complexes contain CEN2, that CEN2 interacts directly with XPC, and that CEN2, in cooperation with HR23B, stabilizes XPC, which stimulates XPC NER activity in vitro. CEN2 has been shown to play an important role in centrosome duplication. Thus, those findings suggest that the XPC-CEN2 interaction may reflect coupling of cell division and NER.

A ‘cassette’ RNase

RNase S is a unique protein comprising the non-covalent association of two components, the S-peptide and the S-protein. An RNA-recognition segment derived from the human immunodeficiency virus (HIV)-1 Rev protein was conjugated with the S-peptide to form a complex with the S-protein. The resulting RNase S bearing the RNA-recognition segment preferentially hydrolyzed a single position of the RNA stem-loop derived from the specific binding site for the Rev protein.

Diversity of the damage recognition step in the global genomic nucleotide excision repair in vitro

The XPC-HR23B complex, a mammalian factor specifically involved in global genomic nucleotide excision repair (NER) has been shown to bind various forms of damaged DNA and initiate DNA repair in cell-free reactions. To characterize the binding specificity of this factor in more detail, a method based on immunoprecipitation was developed to assess the relative affinity of XPC-HR23B for defined lesions on DNA. Here we show that XPC-HR23B preferentially binds to UV-induced (6-4) photoproducts (6-4PPs) as well as to cholesterol, but not to the cyclobutane pyrimidine dimer (CPD), 8-oxoguanine (8-oxo-G), O6-methylguanine (O6-Me-G), or a single mismatch. Human whole cell extracts could efficiently excise 6-4PPs and cholesterol in an XPC-HR23B-dependent manner, but not 8-oxo-G, O6-Me-G or mismatches. Thus, there was good correlation between the binding specificity of XPC-HR23B for certain types of lesion and the ability of human cell extracts to excise these lesions, supporting the model that XPC-HR23B initiates global genomic NER. Although, XPC-HR23B does not preferentially bind to CPDs, the excision of CPDs in human whole cell extracts was found to be absolutely dependent on XPC-HR23B, in agreement with the in vivo observation that CPDs are not removed from the global genome in XP-C mutant cells. These results suggest that, in addition to the excision repair pathway initiated by XPC-HR23B, there exists another sub-pathway for the global genomic NER that still requires XPC-HR23B but is not initiated by XPC-HR23B. Possible mechanisms will be discussed.

Developmental potency of cultured pineal cells: an approach to pineal developmental biology

The pineal organ is still an enigma in regard to its developmental and phylogenetic origin. Little is known of the mechanism involved in determination and differentiation of pineal cells and virtually no studies have been done on the induction and tissue interactions during pinealogenesis. Interest is also centered on the evolutional transformation in structure and function, which may be related to the developmental alterations in pineal morphogenesis between the lower and higher vertebrate species. For developmental studies, avian embryos have great advantages for various experimental manipulations, such as cell and organ culture, surgical operation, and in situ transfection of developmental genes. The present review describes our cell culture studies, which have been done on developing rat and quail pineal organs, in order to elucidate the developmental potency of pineal cells and the regulatory mechanism involved in the phenotypic expression of cell properties. A number of phenotypes including numerous neuron-specific substances are shown immunohistochemically to be expressed only under culture conditions, and not observed in the mature pineal organ. As development proceeds, some of the potencies for cell differentiation are lost; hence, in the mature pineal organs most neuronal phenotypes are not expressed. Numerous factors were discovered which affect phenotypic expression of cultured pineal cells in a cell-type-specific manner. These findings, together with immunohistochemical observations on developing pineal organs, reveal that the developing pineal organ is a unique and useful model system for developmental neurobiology and that cell culture techniques offer a powerful tool for the understanding of development and cell differentiation of this particular organ.

Synthetic inhibitors of the processing of pretransfer RNA by the ribonuclease P ribozyme: enzyme inhibitors which act by binding to substrate

2,2'-p-Phenylene bis[6-(4-methyl-1-piperazinyl)]benzimidazole, 2,2'-bis(3,5-dihydroxyphenyl)-6,6'-bis benzimidazole, and 2,2'-bis(4-hydroxyphenyl)-6,6'-bis benzimidazole are shown by UV-visible and fluorescence spectrophotometry to be strong ligands for tRNA, giving simple, hyperbolic binding isotherms with apparent dissociation constants in the micromolar range. Hydroxyl radical footprinting indicates that they may bind in the D and T loops. On the basis of this tRNA recognition as a rationale, they were tested as inhibitors of the processing of precursor tRNAs by the RNA subunit of Escherichia coli RNase P (M1 RNA). Preliminary studies show that inhibition of the processing of Drosophila tRNA precursor molecules by phosphodiester bond cleavage, releasing the extraneous 5'-portion of RNA and the mature tRNA molecule, was dependent on both the structure of the inhibitor and the structure of the particular tRNA precursor substrate for tRNA(Ala), tRNA(Val), and tRNA(His). In more detailed followup using the tRNA(His) precursor as the substrate, experiments to determine the concentration dependence of the reaction showed that inhibition took time to reach its maximum extent. I(50) values (concentrations for 50% inhibition) were between 5.3 and 20.8 microM, making these compounds among the strongest known inhibitors of this ribozyme, and the first inhibitors of it not based on natural products. These compounds effect their inhibition by binding to the substrate of the enzyme reaction, making them examples of an unusual class of enzyme inhibitors. They provide novel, small-molecule, inhibitor frameworks for this endoribonuclease ribozyme.

Trihalomethane removal by activated carbon fiber

For the safety of drinking water, trihalomethanes are removed by adsorption onto activated carbon fiber from single-component solutions. The amounts adsorbed onto adsorbents with large surface area and/or pore volume were small. Stronger surface hydrophobicity of adsorbent was correlated with a larger amount of trihalomethanes adsorbed. A trihalomethane with bromine was adsorbed to a greater extent than that with chlorine. The differences in the amounts adsorbed among trihalomethanes can be explained by the polarity of trihalomethane molecules. The amount of trihalomethanes adsorbed was mainly dominated by the strength of hydrophobicity of activated carbon fibers.

Spontaneous otoacoustic emissions in humans with endolymphatic hydrops

OBJECTIVE/METHODS

The origin and clinical implications of spontaneous otoacoustic emissions (SOAEs) have not been well revealed. To investigate the relationship between the ear with endolymphatic hydrops and SOAE, SOAEs were measured in 31 patients with unilateral endolymphatic hydrops and 10 volunteers with normal hearing levels that had less than 25 dB hearing level (HL) on average for five frequencies (0.25, 0.5, 1, 2, and 4 kHz).

RESULTS

SOAEs were detected in 18 (58%) of the 31 ears with hydrops. In 15 hydropic ears in which the hearing levels were less than 25 dB HL on average, SOAEs were observed in 11 (73%). The results of examining the relationship between changes in hearing level after administering the glycerol test and SOAE frequency showed that four (50%) of eight hydropic ears had SOAEs that were detectable between the frequency in which hearing level improved more than 5 dB and the frequency with no hearing level change in the audiogram. In 28 contralateral ears, except for three cases of delayed endolymphatic hydrops, SOAEs were detected in 17 (61%). In 14 contralateral ears in which the hearing levels were less than 25 dB HL on average for the five frequencies noted above, SOAEs were observed in nine ears (64%). In 20 normal ears, SOAEs were detected in eight (40%). Prevalence of SOAEs in hydropic ears and contralateral ears of the patients with unilateral hydrops tended to be greater than that in normal ears; however, there was no significant statistical difference between them.

CONCLUSION

The present results suggest that it is not possible to mention the characteristics of SOAE in the hydropic ear only in terms of the prevalence of SOAEs. SOAEs may occur in a specific portion of the basilar membrane corresponding to the frequency in which hearing levels improve after the glycerol test, in some cases with endolymphatic hydrops.

Expression of monocyte chemoattractant protein-1 in peritoneal endometriotic cells

It is well known that the number of peritoneal macrophages is increased in patients with pelvic endometriosis. We measured the concentration of monocyte chemoattractant protein-1 (MCP-1) using an enzyme-linked immunosorbent assay (ELISA) in the peritoneal fluid of women with and without endometriosis. The expression of MCP-1 in pelvic endometriotic lesions obtained from the peritoneum was also examined using immunohistochemistry and nonradioactive in situ hybridization. The mean concentration of MCP-1 in the peritoneal fluid was significantly higher in the patients with endometriosis (P<0.05). The most significant elevation, compared with non-endometriosis patients, was found in stage I of the disease (P<0.05). However, no statistically significant difference was found among endometriosis stages I, II, III, and IV. Immunohistochemical staining revealed that MCP-1-positive cells were localized in the glandular epithelium of the endometriotic lesions and in the stromal macrophages distributed in those lesions, but normal peritoneal cells were negative. The in situ hybridization method demonstrated expression of MCP-1 mRNA on the endometriotic glandular epithelium and stromal macrophages. These findings suggest that MCP-1 may be involved in the histogenesis and early development of peritoneal endometriosis.

Effects of glucose, vitamins, and DO concentrations on pyruvate fermentation using Torulopsis glabrata IFO 0005 with metabolic flux analysis

The effects of glucose, vitamins, and DO concentrations on efficient pyruvic acid fermentation were investigated using Torulopsis glabrata IFO 0005, and a novel biphasic culture method was developed on the basis of the metabolic flux analysis. T. glabrata requires the four vitamins nicotinic acid (NA), thiamine hydrochloride (B(1)), pyridoxine hydrochloride, and biotin for cell growth. The deficiency of these vitamins plays an essential role in pyruvate fermentation. In the present study, we considered the effects of the first two vitamins on the pyruvate fermentation. On the basis of several batch and fed-batch experiments, it was found that, as a result of glucose inhibition of cell growth, the initial glucose concentration should be around 30-40 g/L, and the glucose concentration during fermentation should be controlled at high level around 30 g/L. On the basis of an analysis of carbon flux distribution, a biphasic fermentation method was developed where the cultivation started with a high DO (at 40-50% of air saturation) for efficient cell growth and then was reduced to 5-10% for efficient pyruvate production. Since a fair amount of ethanol was formed when the DO concentration was decreased, the addition of NA turned out to be effective in reducing the ethanol formation. This may be due to a relaxing of the requirement for NADH oxidation by the alcohol dehydrogenase pathway. Since B(1) affects both the pyruvate dehydrogenase complex and pyruvate decarboxylase, its initial concentration must be carefully determined by considering both the cell growth and pyruvate production phases.