Biomedical subjects

M Nakata

Publications and source records attributed to M Nakata.

At least 37 records · Page 2Linked to original sources

PubMed2003

Occlusal phase of gum-chewing strokes.

The occlusal phase of chewing is especially interesting because food particles are being pulverized in this phase. For efficient chewing the upper and lower teeth must come together in a congruent fashion with less variation than in other phases. To examine this expectation the chewing motions of 28 women were recorded optoelectrically, and their frontal and sagittal angles of the closing and following opening strokes were measured at 3.0 mm (3-D linear distance) of opening. Closing strokes were more stable than opening strokes. The frontal angle was correlated with the sagittal angle during closing. The opening and closing sagittal angles were moderately correlated, and the opening and closing frontal angles were negatively correlated at the intersubject level. No direct association was found between the closing strokes and following opening strokes at the intra-subject level. These results suggest that closing strokes are more stable than opening strokes, resulting in efficient mastication.

Adult↗

PubMed2003

Food texture differences affect energy metabolism in rats.

Dietary factors such as taste and nutrients are known to affect satiety and energy balance. We hypothesized that food texture might contribute to the regulation of energy metabolism through the process of mastication in the oral cavity as well. The effects of long-term feeding of different-textured pellets on body weight gain, adiposity, and thermogenesis were assessed. From weaning at 4 wks, rats were divided into 2 groups fed on either standard (controls) or soft pellets (soft-fed) that required less chewing with the same nutritional composition. At 26 wks, the soft-fed rats showed greater adiposity than did the controls. Daily food intake did not differ between the 2 groups. The increase in body temperature following feeding was significantly lower in the soft-fed rats. These results suggested that food texture affected energy metabolism by changing post-prandial thermogenesis. The long-term deficiency of thermogenesis associated with soft foods resulted in a greater tendency toward obesity.

Adipose Tissue↗

PubMed2003

Longitudinal observation of basic mandibular movements: report of a case.

Sound development of mandibular function during childhood is indispensable to establishing healthy function in adults. To examine this developmental process, longitudinal recordings of basic mandibular movements were done using an optoelectronic analysis. Mandibular movements were recorded on five separate occasions in one boy, from an age of six years and five months to 14 years and five months. The incisor pathways during protrusion and lateral excursion were initially shallow, with more anterior than inferior movement, but as he grew the amount of inferior movement and the amount of rotation both increased. Similarly, at his first recording there was very little hinge-like rotation during mouth closing, but rotation increased markedly after eruption of his permanent second molars. These findings suggest that mandibular movements change from being relatively simple with more translation in younger children to more complex movements with more rotation once the permanent dentition is established.

Adolescent↗

PubMed2002

Salivary cystatins influence ingestion of capsaicin-containing diets in the rat.

Dietary capsaicin consumed by rats over several days induces cystatin-like substances in submandibular saliva. Yet the physiological role of these salivary proteins has not been thoroughly investigated. Salivary cystatins in the rat submandibular glands are known to be induced by chronic treatment with the sympathetic beta-agonist, isoproterenol. In the present study, the possible roles of the salivary proteins on food intake were examined by comparing consumption of a capsaicin-adulterated (0.05%) diet in rats with and without isoproterenol pretreatment (0.1 and 5.0 mg/kg, 5 days). Electrophoretic analysis performed prior to feeding trials revealed that the group pretreated with 5 mg/kg isoproterenol had large amounts of cystatin in the saliva compared with the group pretreated with 0.1 mg/kg isoproterenol and control group. The group treated with 5 mg/kg isoproterenol showed greater consumption of the capsaicin-adulterated diet than the other groups until the 3rd day of trials. Bilateral removal of the submandibular and sublingual glands neutralized the effects of isoproterenol. Induction of salivary cystatins by isoproterenol treatment was not mimicked by systemic and intragastric administration of capsaicin. These results suggest that cystatins are included in the salivary proteins induced by capsaicin and that they contribute to enhanced ingestion of the capsaicin diet. Induction of salivary cystatins may be triggered by irritation of the oral mucosa by capsaicin.

Analysis of Variance↗

PubMed2002

Incisal and condylar paths during habitual mouth opening movement of children with anterior reverse bite in the primary dentition.

The purpose of this study was to evaluate whether the path of habitual mouth opening was influenced by anterior reverse bite malocclusion in children. Two groups of children with the primary dentition were chosen: (i) 10 children with anterior reverse bite (reverse bite group) and (ii) 10 with normal occlusion (normal occlusion group). Their habitual mouth opening movements were measured by an opto-electronic movement-analysing system with 6 d.f. at a sampling rate of 100 Hz. These movements were projected on the sagittal plane at the incisal and condylar points. To characterize the path, we used the angles between the path and the horizontal plane. In the initial stage of opening, the incisal path of the reverse bite group was displaced more posteriorly from the intercuspal position than that of the normal occlusion group. However, as opening continued, the direction of the path of the reverse bite group was more anterior than those of the normal occlusion group. During the entire opening movement, the condylar path of the reverse bite group was flatter than those of the normal occlusion group. In conclusion, it was demonstrated that anterior reverse bite in the primary dentition clearly affects the paths of habitual opening movements.

Analysis of Variance↗

PubMed2002

Length of the occlusal glide at the lower incisal point during chewing.

The purpose of this study was to estimate the length of the occlusal glide during gum chewing at the lower incisal point. Mandibular excursions with occlusal contacts in 25 females with permanent dentition were recorded using an optoelectronic system that can measure mandibular movement with 6 d.f. at a sampling frequency of 100 Hz. A curved mesh diagram of incisor coordinates during maximum mandibular excursions (CMDME) was plotted. Gum chewing movement was also measured using the same system and computer software which divided the chewing movement into cycles at each maximum opening position. Each cycle was standardized at 0.1 mm intervals from the most closed position. Finally, the distance between the CMDME and each position of the incisor during a chewing cycle was calculated. Whenever, this distance was less than 0.2 mm opposing teeth were considered to be in contact. The occlusal glide was defined as the distance travelled by the lower incisal point as the mandible moved along occlusal contacts of the CMDME. The vertical coordinates at the beginning of the occlusal glide (during closing) and at the end of occlusal glide (during opening) were also calculated. The lengths of the occlusal glide pathway averaged 1.29 mm during closing and 1.55 mm during opening, a total length of 2.84 mm. Mean vertical coordinates at the beginning and end of the glide were -0.95 and -1.12 mm from intercuspal position, respectively.

Adult↗

PubMed2002

Prenatal diagnosis of congenital epulis: a case report.

Congenital epulis or congenital granular cell tumor, is a benign tumor that has rarely been diagnosed prenatally. We report a case of a large congenital epulis diagnosed at 26 weeks of gestation that increased in size during gestation. Color and power Doppler ultrasound examination showed marked blood flow in the tumor. The tumor could be resected completely following Cesarean section and histologically examined. We discuss the prenatal diagnosis and histogenesis of congenital epulis.

Adult↗

PubMed2001

Abnormal IgG galactosylation and arthritis in MRL-Fas(lpr) or MRL-FasL(gld) mice are under the control of the MRL genetic background.

MRL mice bearing the lpr (Fas) or gld (Fas ligand) mutation, MRL-Fas(lpr) or MRL-FasL(gld), respectively, develop arthritis similar to rheumatoid arthritis, but C3H and C57BL/6 mice bearing such mutations do not. In MRL-Fas(lpr) mice, agalactosylated oligosaccharides in serum IgG increase significantly in comparison to MRL-+/+ mice without arthritis. In this study, an increased level of agalactosylation in IgG, as compared to MRL-+/+, was found in both MRL-Fas(lpr) and MRL-FasL(gld) mice. In contrast, the incidence of IgG without galactose was comparable among C3H-Fas(lpr), C3H-FasL(gld), and C3H-+/+ mice as well as between C57BL/6-Fas(lpr) and C57BL/6-+/+ mice. These results suggest that the increase in agalactosylated IgG and the development of arthritis in MRL-Fas(lpr) and MRL-FasL(gld) mice are controlled by the MRL genetic background.

Animals↗

PubMed2001

Patterns in hybrid nematic liquid-crystal films: topography and topology.

Spontaneous pattern formation in hybrid nematic liquid-crystal films on glycerol was studied with both polarized transmission and unpolarized monochromatic reflected light microscopy. These observations reveal that the patterns that are found in 1 to 10-microm-thick films are due to a combination of film topography, gradients in film thickness that act as an aligning field, and topology, connectivity requirements on the vector field. The patterns studied include cellular patterns, disclinations connected by 2pi-walls, and 2pi-walls that narrow to a point at the edge of the films.

Journal Article↗

PubMed2001

An ancient lectin-dependent complement system in an ascidian: novel lectin isolated from the plasma of the solitary ascidian, Halocynthia roretzi.

Mannose-binding lectin (MBL) is a C-type lectin involved in the first line of host defense against pathogens and it requires MBL-associated serine protease (MASP) for activation of the complement lectin pathway. To elucidate the origin and evolution of MBL, MBL-like lectin was isolated from the plasma of a urochordate, the solitary ascidian Halocynthia roretzi, using affinity chromatography on a yeast mannan-Sepharose. SDS-PAGE of the eluted proteins revealed a major band of approximately 36 kDa (p36). p36 cDNA was cloned from an ascidian hepatopancreas cDNA library. Sequence analysis revealed that the carboxy-terminal half of the ascidian lectin contains a carbohydrate recognition domain (CRD) that is homologous to C-type lectin, but it lacks a collagen-like domain that is present in mammalian MBLs. Purified p36 binds specifically to glucose but not to mannose or N-acetylglucosamine, and it was designated glucose-binding lectin (GBL). The two ascidian MASPs associated with GBL activate ascidian C3, which had been reported to act as an opsonin. The removal of GBL-MASPs complex from ascidian plasma using Ab against GBL inhibits C3-dependent phagocytosis. These observations strongly suggest that GBL acts as a recognition molecule and that the primitive complement system, consisting of the lectin-proteases complex and C3, played a major role in innate immunity before the evolution of an adaptive immune system in vertebrates.

Amino Acid Sequence↗

PubMed2001

Identification of N(omega)-carboxymethylarginine, a new advanced glycation endproduct in serum proteins of diabetic patients: possibility of a new marker of aging and diabetes.

A new advanced glycation end product (AGE), N(omega)-carboxymethyl-arginine (CMA), was found in acid-soluble skin collagen of a newborn bovine prepared by in vitro glycation with 1 M glucose incubation at 37 degrees C for about 30 days [ 1 ]. CMA production was increased with incubation time in parallel, and after 30 days incubation the yield was 100 times higher than that of pentosidine [ 1 ]. This result suggested the importance of CMA as a major AGE in collagen. We have detected and measured the CMA level in human serum proteins by electrospray ionization/liquid chromatography/mass spectrometry (ESI/LC/MS), using CMA standard concentration curve. In this report, we first show the existence of CMA in vivo, and its serum level is significantly elevated in diabetic serum proteins, compared to age-matched control serum proteins. These results provide strong evidence that CMA is a new diagnostic marker of glycation in diabetes.

Aging↗

PubMed2001

Holes and disclinations in hybrid nematic liquid crystal films.

Defect patterns in hybrid nematic liquid crystal films of pentylcyanobiphenyl (5CB) on a glycerol surface were studied with polarized transmission and monochromatic reflected light microscopy. We report that disclinations of apparent topological strength zero, stable pairs of +1 and -1 disclinations, and higher strength defects found in these films are stabilized by holes in the liquid crystal film. These holes are produced by a monolayer of surfactant on the glycerol surface. In addition, we describe the topology of the director field in the film during the coalescing of two such holes.

Journal Article↗

PubMed2001

Rapid and simple preparation of N-linked oligosaccharides by cellulose-column chromatography.

As a means of preparing N-linked oligosaccharides from hydrazinolysates of glycoproteins in a rapid and simple manner, a method has been developed using cellulose-column chromatography. Hydrazinolysates of human IgG, containing a series of biantennary complex type oligosaccharides, were applied to a cellulose column equilibrated with (4:1:1, v/v) 1-butanol-ethanol-water. The N-linked oligosaccharides were eluted with (1:1, v/v) ethanol-water, and analyzed by HPLC in combination with sequential glycosidase digestion. The oligosaccharides, with or without sialic acid, were quantitatively recovered in the fraction eluted with (1:1, v/v) ethanol-water without UV-detectable contamination by impurities derived from protein or the cellulose. Other types of N-linked oligosaccharides of alpha1-acid glycoprotein (tetraantennary complex-type), ovalbumin (hybrid-type), and ribonuclease B (high mannose-type) were also quantitatively prepared from the hydrazinolysates by elution of the cellulose column with (1:1, v/v) ethanol-water and these had as high a quality as those prepared by conventional paper chromatography.

Animals↗

PubMed2001

Role of galactosylation in the renal pathogenicity of murine immunoglobulin G3 monoclonal cryoglobulins.

Cryoglobulin activity associated with murine immunoglobulin G3 (IgG3) has been shown to play a significant role in the development of murine lupuslike glomerulonephritis. A fraction, but not all, IgG3 monoclonal antibodies are capable of inducing a severe acute lupuslike glomerulonephritis as a result of direct localization of IgG3 cryoglobulins, suggesting the importance of qualitative features of cryoglobulins in their nephritogenic activities. Here a remarkable difference is shown in the renal pathogenicity of 2 murine IgG3 monoclonal cryoglobulins, identical in the amino acid sequences of their heavy and light chains but different in galactosylation patterns of oligosaccharide side chains because of their synthesis in different myeloma cells. The antibody lacking the capacity to induce severe glomerulonephritis displayed an increased proportion of galactosylated heavy chains. Changes in conformation, as revealed by gel filtration analysis, reduced cryoglobulin activity, and accelerated clearance could account for the lack of the renal pathogenicity of the more galactosylated variant. This observation provides a direct demonstration for the role of IgG galactosylation in the pathogenic potential of cryoglobulins. (Blood. 2001;97:3537-3543)

Animals↗

PubMed2001

Molecular orientation near the surface of a smectic liquid crystal cell showing V-shaped switching by means of attenuated total internal reflection ellipsometry.

Attenuated total internal reflection ellipsometry was used to probe the molecular orientation and switching near the surface of a smectic liquid crystal cell showing V-shaped switching. We find that the switching occurs collectively near the surface as in the bulk. The molecules form a twisted state, but the twist angle relative to the bulk layer normal is small because of compensating twist of the smectic layer normal. As a result, a rather uniform molecular orientation is produced, resulting in high extinction and a high contrast ratio in the absence of a field.

Journal Article↗

PubMed2001

Simultaneous quantification of components of neoglycolipid-coated liposomes using high-performance liquid chromatography with evaporative light scattering detection.

Liposomes composed of dipalmitoylphosphatidylcholine (DPPC), cholesterol and a neoglycolipid, mannopentaose-conjugated dipalmitoylphosphatidylethanolamine (Man5-DPPE), have been shown to have a strong adjuvant effect in inducing the antigen-specific cellular immunity. In this study, a rapid and simple analytical method using a HPLC system with an evaporative light scattering detector was developed for simultaneous quantification of the liposome components Man5-DPPE, cholesterol and DPPC. The chromatographic separation of these components was performed using a trimethylsilane column with an isocratic mobile phase of chloroform-methanol-water (1:33:6, v/v) after disrupting the liposomes with chloroform-methanol-water (10:10:3, v/v). This HPLC method provided sufficient reproducibility and linearity of calibration curves for the quantification of the liposome constituents. In addition, this method can be used for the quantification of various neoglycolipids with different carbohydrate structures.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed2001

Cloning and characterization of novel ficolins from the solitary ascidian, Halocynthia roretzi.

Ficolins are animal lectins with collagen-like and fibrinogen-like domains. They are involved in the first line of host defense against pathogens. Human ficolin/P35 as well as mannose-binding lectin (MBL) activates the complement lectin pathway in association with MBL-associated serine proteases. To elucidate the origin and evolution of ficolins, we separated approximately 40 kDa (p40) and approximately 50 kDa (p50) N-acetylglucosamine-binding lectins from hemolymph plasma of the solitary ascidian. Binding assays revealed that p40 recognizes N-acetyl groups in association with a pyranose ring and that p50 recognizes N-acetylglucosamine alone. Based on the amino acid sequences of the proteins, we isolated two clones each of p40 and p50 from the ascidian hepatopancreas cDNA and determined the entire coding sequences of these clones. Because all of the clones contained both collagen-like and fibrinogen-like domains, we concluded that these were homologs of the mammalian ficolin family and designated ascidian ficolins (AsFCNs). The fibrinogen-like domain of the AsFCNs shows 45.4-52.4% amino acid sequence identity with the mammalian ficolin family. A phylogenetic tree of the fibrinogen-like sequences shows that all the fibrinogen-like domains may have evolved from a common ancestor that branched off an authentic fibrinogen. These results suggest that AsFCNs play an important role with respect to ascidian hemolymph lectin activity and the correlation of different functions with binding specificity.

Amino Acid Sequence↗

PubMed2001

The first total synthesis of concanamycin f (concanolide a).

A highly stereoselective total synthesis of the macrolide antibiotic concanamycin F (1), a specific and potent inhibitor of vacuolar H(+)-ATPase, has been achieved by a convergent route involving the synthesis and coupling of its 18-membered tetraenic lactone and beta-hydroxyl hemiacetal side chain subunits. The C1-C19 18-membered lactone aldehyde 4 was synthesized through the intermolecular Stille coupling of the C5-C13 vinyl iodide 24 and the C14-C19 vinyl stannane 25, followed by construction of the C1-C4 diene and macrolactonization. Synthesis of 4 via a second convergent route including the esterification of the C1-C13 vinyl iodide 45 and the C14-C19 vinyl stannane 47 followed by the intramolecular Stille coupling was also realized. The highly stereoselective aldol coupling of 4 and the C20-C28 ethyl ketone 5 followed by desilylation provided 1 which was identical with natural concanamycin F.

Anti-Bacterial Agents↗