Twenty Years-Passed Case of Demineralized Dentin Matrix Autograft for Sinus Bone Augmentation - A First Case of Dentin Graft in Human

This report presents a 20-year follow-up of a unique case involving a 46-year-old man who underwent sinus augmentation using autogenous demineralized dentin matrix (DDM) derived from non-functional teeth. Two extracted molars were crashed into granules, and then demineralized, freeze-dried, and stored at -80° for approximately one year. The stocked DDM granules were grafted into the sinus along with platelet-rich plasma, without the use of any membrane. Radiographic evidence at 1 month after the graft demonstrated successful harmonization of the augmented tissues with the atrophic maxilla, as shown by the increase in radiopaque dots. Computed tomography scans taken 5 months post-procedure revealed clear sinuses devoid of inflammation, significant bone formation, and a smooth buccal side outline. Bone biopsies at 5 months were carried out from the implant sites, and three fixtures were placed into the augmented bone. The biopsy tissues confirmed the presence of continuous trabecular bone linked with DDM, with new bone formation observed on it. A comparison of the dental X-ray images taken in 2009 and those captured in 2021 indicated minimal change in the outline of the new bone formed near the fixture-necks through the DDM graft and successful placement of dental implants was achieved. Based on this long-term case study, it is suggested that autogenous DDM graft could serve as a minimally invasive alternative for sinus bone augmentation without invasive bone harvesting and the associated morbidities. Key words:Atrophic maxilla, autograft, bone, dentin, demineralized dentin matrix, sinus augmentation, teeth.

Primary Teeth-Derived Demineralized Dentin Matrix Autograft for Unilateral Maxillary Alveolar Cleft during Mixed Dentition

This clinical report describes the immediate autograft of primary (milk) teeth-derived demineralized dentin matrix (DDM) granules for a 6-year-old boy with unilateral alveolar cleft. First, four primary teeth were extracted, crushed in an electric mill for 1 min, and the crushed granules were demineralized in 2% HNO₃ solution for 20 min. Simultaneously, the nasal mucoperiosteum was pushed upwards above the apices of the permanent central incisor adjacent to the cleft. The nasal and palatal openings were closed by suturing the mucoperiosteum on both sides of the cleft with absorbable threads. The wet DDM granules were grafted into the managed cleft triangle space, and a labial flap was repositioned. The radiographic images at 6 months showed the continuous hard tissues in the cleft area and DDM granules onto lateral incisor (22) and impacted canine (23). The 3D-CT views at 2 years showed impacted tooth (22) blocked by primary canine and the replacement of DDM granules by bone near teeth (22,23). At 4 years, tooth crown (22) was situated just under the mucous membrane, and teeth (22,23) erupted spontaneously until 6 years without a maxillary expansion and a tow guidance of canine. The DDM granules contributed to bone formation without the inhibition of spontaneous tooth eruption. We concluded that autogenous primary teeth DDM graft should become a minimally invasive procedure without bone harvesting and morbidities for unilateral alveolar cleft.

Immediate Tooth Autotransplantation with Root Canal Filling and Partially Demineralized Dentin/Cementum Matrix into Congenital Missing Tooth Region

This clinical report describes immediate tooth auto-transplantation with an autograft of partially demineralized dentin/cementum matrix (pDDM), based on an orthodontic treatment plan for a 16-year-old male patient with a congenital missing tooth (#45). First, vital teeth (#14, #24) were extracted, and root canal filling (#14) was immediately performed with the support of a fixation device. Simultaneously, the tooth (#24) was crushed in an electric mill for 1 min, and the crushed granules were partially demineralized in 2% HNO₃ solution for 20 min as the graft material. Next, the donor tooth was transplanted into the created socket (#45), and stabilized using an enamel bonding agent. The wet pDDM was loaded into the location of the congenital missing tooth, and the flap was repositioned. The bonding agent for stabilization was removed at 28 days, and also small contact points between the transplanted tooth and the upper premolar (#14) were added using photopolymerizable composite resin. X-ray photos were taken sequentially, and there were no postoperative complications. The radiographic images showed that the periodontal ligament space and alveolar ridge line could be observed at 18 months. The pDDM was harmonized with the mandible, and the remodeled bone-like shadow was observed in the graft region. We concluded that immediate tooth transplantation with root canal fillings and autogenous pDDM may be a valuable alternative to dental implanting or bridge formation for patients with a congenital missing tooth, followed by orthodontic treatment.

Histological Evidences of Autograft of Dentin/Cementum Granules into Unhealed Socket at 5 Months after Tooth Extraction for Implant Placement

The aim of this clinical case study was to observe biopsy tissues at 5 months after an autograft of a partially demineralized dentin/cementum matrix (pDDM) into a tooth-extracted socket exhibiting healing failure. A 66-year-old female presented with healing failure in the cavity for 2 months after the extraction (#36). Initial X-ray photos showed a clear remainder of lamina dura (#36), a residual root (#37), and a horizontal impaction (#38). The vital tooth (#38) was selected for pDDM. The third molar crushed by electric mill was decalcified in 1.0 L of 2.0% HNO₃ for 20 min and rinsed in cold distilled water. The pDDM granules (size: 0.5–2.0 mm) were grafted immediately into the treated socket. X-ray views just after pDDM graft showed radio-opaque granules. At 5 months after pDDM graft, the surface of regenerated bone was harmonized with the mandibular line, and bone-like radio-opacity was found in the graft region. The biopsy tissue (diameter: 3.0 mm) at 5 months after pDDM graft showed that mature bone was interconnected with the remaining pDDM. The novel histological evidence highlighted that newly formed bone was connected directly with both dentin-area and cementum-area matrix of pDDM. We concluded that pDDM contributed to the regeneration of bone in the unhealed socket, and this regeneration prepared the socket for implant placement. Autogenous pDDM could be immediately recycled as an innovative biomaterial for local bone regeneration.

Chemical Properties of Human Dentin Blocks and Vertical Augmentation by Ultrasonically Demineralized Dentin Matrix Blocks on Scratched Skull without Periosteum of Adult-Aged Rats

Vertical augmentation is one of the most challenging techniques in bone engineering. Several parameters, such mechano-chemical characteristics, are important to optimize vertical bone regeneration using biomaterials. The aims of this study were to chemically characterize human dentin blocks (calcified demineralized dentin matrix: CDM, partially demineralized dentin matrix: PDDM and completely demineralized dentin matrix: CDDM) (2 × 2 × 1 mm³) chemically and evaluate the behavior of PDDM blocks on non-scratched or scratched skulls without periosteum of adult rats (10–12 months old, female) as a vertical augmentation model. The dissolved efficiency of CDM showed 32.3% after ultrasonic demineralization in 1.0 L of 2% HNO₃ for 30 min. The 30 min-demineralized dentin was named PDDM. The SEM images of PDDM showed the opening of dentinal tubes, nano-microcracks and the smooth surface. In the collagenase digestion test, the weight-decreasing rates of CDM, PDDM and CDDM were 9.2%, 25.5% and 78.3% at 12 weeks, respectively. CDM inhibited the collagenase digestion, compared with PDDM and CDDM. In the PDDM onlay graft on an ultrasonically scratched skull, the bone marrow-space opening from original bone was found in the bony bridge formation between the human PDDM block and dense skull of adult senior rats at 4 and 8 weeks. On the other hand, in the cases of the marrow-space closing in both non-scratched skulls and scratched skulls, the bony bridge was not formed. The results indicated that the ultrasonic scratching into the compact parietal bone might contribute greatly to the marrow-space opening from skull and the supply of marrow cells, and then bony bridge formation could occur in the vertical augmentation model without a periosteum.

Mechanical Properties of Human Concentrated Growth Factor (CGF) Membrane and the CGF Graft with Bone Morphogenetic Protein-2 (BMP-2) onto Periosteum of the Skull of Nude Mice

Concentrated growth factor (CGF) is 100% blood-derived, cross-linked fibrin glue with platelets and growth factors. Human CGF clot is transformed into membrane by a compression device, which has been widely used clinically. However, the mechanical properties of the CGF membranes have not been well characterized. The aims of this study were to measure the tensile strength of human CGF membrane and observe its behavior as a scaffold of BMP-2 in ectopic site over the skull. The tensile test of the full length was performed at the speed of 2mm/min. The CGF membrane (5 × 5 × 2 mm3) or the CGF/BMP-2 (1.0 μg) membrane was grafted onto the skull periosteum of nude mice (5-week-old, male), and harvested at 14 days after the graft. The appearance and size of the CGF membranes were almost same for 7 days by soaking at 4 °C in saline. The average values of the tensile strength at 0 day and 7 days were 0.24 MPa and 0.26 MPa, respectively. No significant differences of both the tensile strength and the elastic modulus were found among 0, 1, 3, and 7 days. Supra-periosteal bone induction was found at 14 days in the CGF/BMP-2, while the CGF alone did not induce bone. These results demonstrated that human CGF membrane could become a short-term, sticky fibrin scaffold for BMP-2, and might be preserved as auto-membranes for wound protection after the surgery.

Evaluation of perforated demineralized dentin scaffold on bone regeneration in critical-size sheep iliac defects

OBJECTIVES

Regenerating critical-size bone injury is a major problem that continues to inspire the design of new graft materials. Therefore, tissue engineering has become a novel approach for targeting bone regeneration applications. Human teeth are a rich source of stem cells, matrix, trace metal ions, and growth factors. A vital tooth-derived demineralized dentin matrix is acid-insoluble and composed of cross-linked collagen with growth factors. In this study, we recycled human non-functional tooth into a unique geometric dentin scaffold, entitled perforated root-demineralized dentin matrix (PR-DDM). The aim of this study was to evaluate the feasibility of PR-DDM as the scaffold for regenerating bone in critical-size iliac defects.

MATERIAL AND METHODS

Artificial macro-pores (1 mm in diameter) were added to human vital wisdom tooth after removing the enamel and pulp portions. The modified tooth was demineralized in 0.34 N HNO₃ for 30 min and is referred to as PR-DDM scaffold. Critical-size defect (10 mm × 15 mm × 9 mm Ø) was created in the iliac crest of six adult sheep. The in vivo bone regeneration by the scaffold was evaluated by micro-CT, 3D micro-CT, and histological examination at 2 and 4 months post-implantation.

RESULTS

PR-DDM exhibited better bone ingrowth, especially in the artificial macro-pores. The results of micro-CT and 3D micro-CT revealed good union between scaffold and native bone. New bone formation was observed in almost all portions of PR-DDM. Higher bone volume inside the scaffold was detected at 4 months compared with 2 months. New bone ingrowth was ankylosed with PR-DDM, and both osteoinduction and osteoconduction capability of PR-DDM were confirmed histologically. The ratio of new bone formation was higher at 4 months compared with 2 months by histomorphometric analysis.

CONCLUSIONS

Altogether, these results demonstrated that the human tooth-derived graft material with a unique geometric structure, PR-DDM, contributed to active bone ingrowth in critical-size bone defects. This novel scaffold may have great utility in the near-future clinical application.

Tooth-derived bone graft material

With successful extraction of growth factors and bone morphogenic proteins (BMPs) from mammalian teeth, many researchers have supported development of a bone substitute using tooth-derived substances. Some studies have also expanded the potential use of teeth as a carrier for growth factors and stem cells. A broad overview of the published findings with regard to tooth-derived regenerative tissue engineering technique is outlined. Considering more than 100 published papers, our team has developed the protocols and techniques for processing of bone graft material using extracted teeth. Based on current studies and studies that will be needed in the future, we can anticipate development of scaffolds, homogenous and xenogenous tooth bone grafts, and dental restorative materials using extracted teeth.

Acid-insoluble human dentin as carrier material for recombinant human BMP-2

The aim of this study is to estimate the increase of bone-inductive potency by human demineralized dentin matrix (DDM) with recombinant human bone morphogenetic protein-2 (BMP-2). Human teeth were crushed, completely demineralized in 0.6M HCl, and freeze-dried. The tooth-derived material is called DDM. The shape of DDM was a particle type and its size varied from 0.4 to 0.8 mm. The BMP-2 dose-dependent study in the rat subcutaneous tissues demonstrated that the volume of induced bone and marrow increased at a dose-dependent manner. The time-course study of bone induction by the BMP-2 (5.0 μg)/DDM (70 mg) was estimated histologically and biochemically. Histological findings showed that the BMP-2/DDM increased bone and marrow sequentially between the DDM particles. Calcium content in the BMP-2/DDM-induced tissue was compatible to the histological findings. ALP activity in the BMP-2/DDM showed a maximal value at 1 week and gradually decreased. The morphometric analysis demonstrated that the BMP-2/DDM showed 66.9%, 79.0% in the volume of bone and marrow, and 32.4%, 21.0% in that of DDM at 8, 32 weeks, respectively. We confirmed that BMP-2 significantly accelerated bone formation in the acid-insoluble human-dentin carriers. These results indicate that human DDM should be an effective carrier for delivering BMP-2 and superior scaffold for bone-forming cells.

Improved bioabsorbability of synthetic hydroxyapatite through partial dissolution-precipitation of its surface

Even though synthetic hydroxyapatite (HAp) has a chemical composition similar to the mineral phase of bone, it is minimally absorbed and replaced by bone tissue. This could be because HAp is composed of compactly arranged apatite crystals with homogenously large grains. In this study, the surface and non-stoichiometry of the synthetic HAp crystals was modified by partial dissolution and precipitation (PDP) to improve bioabsorbability of HAp. In vitro cell culture demonstrated that more osteoclasts were activated on PDP-HAp compared with HAp. In vivo implantation using a rabbit bone defect model revealed that PDP-HAp was gradually degraded and was replaced by bone tissue. Consistent with the in vitro results, more osteoclasts were activated in PDP-HAp than in HAp, indicating that the former was absorbed through the stimulation of osteoclastic activity. These results suggest that the PDP technique may have clinical utility for modifying synthetic HAp for use as superior bone graft substitutes.

Maturation of catalase precursor proceeds to a different extent in glyoxysomes and leaf peroxisomes of pumpkin cotyledons

As an approach to study the mechanism of the microbody transition (glyoxysomes to leaf peroxisomes) in greening pumpkin cotyledons, catalase molecules were purified from the two different types of microbody and their structural properties were compared. The purified glyoxysomal catalase was found to consist of four identical subunits (55 kDa), whereas the leaf peroxisomal catalase contains two different forms of monomeric subunit (55 and 59 kDa). These different catalase species cross-reacted with the rabbit antibody raised against the glyoxysomal enzyme. During gel filtration on an Ultrogel AcA 34 column, the leaf peroxisomal 55-kDa polypeptide eluted slightly faster than the leaf peroxisomal 59-kDa polypeptide. The profile of catalase activities exactly paralleled the elution pattern of the 55-kDa molecules, which indicated that the 59-kDa polypeptide was enzymically inactive. Peptide mapping analysis using Staphylococcus aureus protease V8 showed that the glyoxysomal 55-kDa polypeptide was identical to the leaf peroxisomal 55-kDa species, whereas the leaf peroxisomal 59-kDa polypeptide had a different primary structure from the 55-kDa polypeptide. In an in vitro translation system directed by mRNA isolated from etiolated and green cotyledons, glyoxysomal and leaf peroxisomal catalases were synthesized as the identical 59-kDa polypeptide. From peptide mapping analysis, the in vitro-translated 59-kDa polypeptide was found to have a nearly identical primary structure to that of the leaf peroxisomal 59-kDa species. In vivo pulse-chase labeling experiments using etiolated cotyledons showed the conversion of the 59-kDa polypeptide to the 55-kDa molecular species. The overall results strongly indicate that the 59-kDa polypeptide is a precursor form of catalase in pumpkin cotyledons.

In vitro proliferation and chondrogenic differentiation of rat bone marrow stem cells cultured with gelatin hydrogel microspheres for TGF-beta1 release

The objective of this study was to evaluate the proliferation and chondrogenic differentiation of rat bone marrow-derived mesenchymal stem cells (MSCs) cultured with gelatin hydrogel microspheres of cell scaffold which can release transforming growth factor-beta1 (TGF-beta1). Gelatin was dehydrothermally cross-linked in different conditions in a water-in-oil emulsion state to obtain gelatin hydrogel microspheres with different water content. The microspheres functioned not only as the scaffold of MSC, but also the carrier matrix of TGF-beta1 release. The MSC proliferation depended on the water content of microspheres. Higher MSC proliferation was observed for the gelatin microspheres with lower water content. When cultured with the gelatin hydrogel microspheres, MSC formed their aggregates, in contrast to culturing with hydrogel sheets. The cell viability was significantly high compared with that of the hydrogel sheet. The production of sulfated glycosaminaglycan (sGAG) from MSC was examined as a measure of chondrogenic differentiation, after their culturing in a normal and chondrogenic differentiation media. For both the cultures, the amount of sGAG produced was significantly higher for MSC cultured with the gelatin microspheres than that of the gelatin sheet. Stronger differentiation of MSC was achieved in culture with the microspheres incorporating TGF-beta1 than that of MSC cultured in the medium containing the same amount of TGF-beta1. It is concluded that the gelatin hydrogel microspheres function well as both the scaffold of MSC and the matrix of TGF-beta1 release, resulting in enhanced MSC aggregation and the consequent promotion of cell proliferation and differentiation.

BMP-2 release and dose-response studies in hydroxyapatite and beta-tricalcium phosphate

The purpose of this study is to compare in vivo retention of BMP-2 and bone induction in HAp (porosity: 60-80%, pore size: 100-600 mum, sintering temperature: 800 degrees C, surface area: 1 m(2)/g) and beta-TCP (porosity: 75%, pore size: 100-400 mum, sintering temperature: 1050 degrees C, surface area: 4 m(2)/g). We estimated the in vivo release profile of (125)I-labeled BMP-2 and bone induction of hard tissues histologically. The amount of BMP-2 remaining in the beta-TCP at 1 day after implantation was 49.6%, while the amount was 34.0% in the HAp. Furthermore, the HAp and beta-TCP containing 0.0, 0.05, 0.1, 0.3, 0.5, 1.0, 5.0 microg of BMP-2 were implanted into the back subcutis of 4-week old Wistar rats. At 3 weeks after implantation, the ceramics were explanted and evaluated histologically. The HAp/BMP-2 (5.0 microg) system showed 3.0% in the total volume of bone at 3 weeks, while only in the beta-TCP/BMP-2 (5.0 microg) system showed 32.5%. These results indicate that the absorbable beta-TCP block may be an effective bioceramic for bone induction to deliver BMP-2 to the site of action.

Blood permeability of a novel ceramic scaffold for bone morphogenetic protein-2

A functionally graded apatite (fg-HAp) with body fluid permeability was developed from bovine bone. The tissue reaction of fg-HAp and its efficacy as a scaffold for recombinant human bone morphogenetic protein-2 (BMP-2) were evaluated histomorphometrically, and a component of permeable fluid into the fg-HAp was analyzed by immunoblotting assay. The fg-HAp block (27 mm(3)) combined with and without BMP-2 (5 microg) was implanted subcutaneously in 4-week-old Wistar rats. Histological examination showed that the surface and bulk degradations of the fg-HAp proceeded extensively and giant cells appeared on the fg-HAp at 2 weeks. Body fluid permeation was found inside the fg-HAp, and the fluid component was immunopositive for albumin. In addition, albumin was detected as a main component among proteins collected from the in vivo implanted fg-HAp. The bioabsorption of the fg-HAp was accelerated as BMP-2-induced bone matured. Histomorphometrical analysis at 4 weeks in the BMP-2/fg-HAp implant showed 59.0% in the total volume of bone and marrow. These results indicate that fg-HAp is an innovative, bioabsorbable bioceramic with fluid permeability characteristic, and may become a biointegrated scaffold for bone engineering.

Usefulness of three-dimensional full-scale modeling of surgery for a giant cell tumor of the cervical spine

STUDY DESIGN

Case report.

OBJECTIVES

To report a case with giant cell tumor (GCT) of C6 vertebra, in which three-dimensional (3-D) full-scale modeling of the cervical spine was useful for preoperative planning and intraoperative navigation.

SETTING

A university hospital in Japan.

CASE REPORT

A 27-year-old man with a GCT involving the C6 vertebra presented with severe neck pain. The C6 vertebra was collapsed and the tumor had infiltrated around both vertebral arteries (VAs). A single-stage operation combining anterior and posterior surgical procedures was scheduled to resect the tumor and stabilize the spine. To evaluate the anatomic structures within the surgical fields, we produced a 3-D full-scale model from the computed tomography angiography data. The 3-D full-scale model clearly showed the relationships between the destroyed C6 vertebra and the deviations in the courses of both VAs. Using the model, we were able to identify the anatomic landmarks around the VAs during anterior surgery and to successfully resect the tumor. During the posterior surgery, we were able to determine accurate starting points for the pedicle screws. Anterior iliac bone graft from C5 to C7 and posterior fixation with a rod and screw system from C4 to T2 were performed without any complications. Postoperatively, the patient experienced relief of his neck pain.

CONCLUSION

The 3-D full-scale model was useful for simultaneously evaluating the destruction of the vertebral bony structures and the deviations in the courses of the VAs during surgery for GCT involving the cervical spine.

Biodegradation and bioabsorption innovation of the functionally graded bovine bone-originated apatite with blood permeability

Bioabsorbable and functionally graded apatite (fg-HAp) ceramics were designed using bovine bone by the calcination and partial dissolution-precipitation methods. The fg-HAp ceramics that were developed had gradual distributions of the degree of crystallinity and the grain size of single-phase hydroxyapatite from the surface layer of the pore wall to the bulk structure region. Calcination at 1073 K gave a specific surface area of 30 m2 x g-1 and porosities of 60-80%. The pore structure of the fg-HAp was classified into two regions: a macro-pore region (100-600 microm) originating from spongy bone and a micro-pore region (10-160 nm) related to body fluid permeation and blood permeability. By implantation in subcutaneous tissue of rat, it was confirmed that body fluid permeated the bulk region of the fg-HAp ceramics through the micro-pores. The volumetric populations occupied by body fluid were 60% at 4 weeks and 68% at 8 weeks in the ceramics explants, indicating drastic bioabsorption, although the body fluid was found to be immunopositive for an albumin as the main serum protein in blood. On the fg-HAp ceramics developed here, the bioabsorption rate could be controlled by careful selection of the calcination temperature. These ceramics can be applied as new biomimetic ceramics exhibiting surface and bulk degradations and cellular absorption by giant cells.

Reappraisal of the currently prevailing model of starch biosynthesis in photosynthetic tissues: a proposal involving the cytosolic production of ADP-glucose by sucrose synthase and occurrence of cyclic turnover of starch in the chloroplast

A vast amount of information has accumulated which supports the view that sucrose and starch are end-products of two segregated, yet highly interconnected, gluconeogenic pathways taking place in the cytosol and chloroplast, respectively. However, several lines of experimental evidences indicate that, essentially identical to the case of heterotrophic tissues, starch formation in the photosynthetic tissues may involve the direct import to the chloroplast of cytosolic hexose (C6) units derived from the sucrose breakdown. This evidence is consistent with the idea that synthesis of a sizable pool of ADP-glucose takes place in the cytosol by means of sucrose synthase whereas, basically in agreement with recent investigations dealing with glycogen biosynthesis in bacteria and animals, chloroplastic phosphoglucomutase and ADP-glucose pyrophosphorylase are most likely playing a role in channelling of glucose units derived from the starch breakdown in the chloroplast, thus making up a regulatory starch turnover cycle. According to this new view, we propose that starch production in the chloroplast is the result of a flexible and dynamic mechanism wherein both catabolic and anabolic reactions take place simultaneously in a highly interactive manner. Starch is seen as an intermediate component of a cyclic gluconeogenic pathway which, in turn, is connected with other metabolic pathways. The possible importance of metabolic turnover as a way to control starch production is exemplified with the recently discovered ADP-glucose pyrophosphatase, an enzyme likely having a dual role in controlling levels of ADP-glucose linked to starch biosynthesis and diverting carbon flow towards other metabolic pathways.

Organization of inputs from cingulate motor areas to basal ganglia in macaque monkey

The cingulate motor areas reside within regions lining the cingulate sulcus and are divided into rostral and caudal parts. Recent studies suggest that the rostral and caudal cingulate motor areas participate in distinct aspects of motor function: the former plays a role in higher-order cognitive control of movements, whereas the latter is more directly involved in their execution. Here, we investigated the organization of cingulate motor areas inputs to the basal ganglia in the macaque monkey. Identified forelimb representations of the rostral and caudal cingulate motor areas were injected with different anterograde tracers and the distribution patterns of labelled terminals were analysed in the striatum and the subthalamic nucleus. Corticostriatal inputs from the rostral and caudal cingulate motor areas were located within the rostral striatum, with the highest density in the striatal cell bridges and the ventrolateral portions of the putamen, respectively. There was no substantial overlap between these input zones. Similarly, a certain segregation of input zones from the rostral and caudal cingulate motor areas occurred along the mediolateral axis of the subthalamic nucleus. It has also been revealed that corticostriatal and corticosubthalamic input zones from the rostral cingulate motor area considerably overlapped those from the presupplementary motor area, while the input zones from the caudal cingulate motor area displayed a large overlap with those from the primary motor cortex. The present results indicate that a parallel design underlies motor information processing in the cortico-basal ganglia loop derived from the rostral and caudal cingulate motor areas.

[Tracheal intubation without muscle relaxants using propofol and varying doses of fentanyl]

This study was designed to evaluate airway and intubating conditions without muscle relaxants after administration of fentanyl and propofol in 55 patients aged 20-60 years for elective surgery. Patients were randomly assigned to one of four groups to receive fentanyl 0, 2, 3, or 4 micrograms.kg-1, respectively. Three minutes after the administration of fentanyl, propofol (2 mg.kg-1) was given for induction of anesthesia. After the loss of consciousness, laryngoscopy and tracheal intubation, supplemented with topical anesthesia of lidocaine (2 mg.kg-1), were attempted. In control group, without administration of fentanyl, all patients were judged to provide poor intubating conditions. Increasing doses of fentanyl reduced the incidences of movement and persistent coughing on laryngoscopy and intubation in a dose-related manner. However, visualization of the vocal cord was significantly. (P < 0.05) more likely to be impossible in patients in 4 micrograms.kg-1 fentanyl group (40%) compared with patients in 2 micrograms.kg-1 fentanyl group (7%). There were no significant differences among groups receiving fentanyl with respect to vocal cord position. The vocal cords were closed in 26% of patients receiving fentanyl and propofol for intubation. Tracheal intubation without muscle relaxants is not recommended because of the potential unacceptable intubating conditions.

Adenosine diphosphate sugar pyrophosphatase prevents glycogen biosynthesis in Escherichia coli

An adenosine diphosphate sugar pyrophosphatase (ASPPase, EC ) has been characterized by using Escherichia coli. This enzyme, whose activities in the cell are inversely correlated with the intracellular glycogen content and the glucose concentration in the culture medium, hydrolyzes ADP-glucose, the precursor molecule of glycogen biosynthesis. ASPPase was purified to apparent homogeneity (over 3,000-fold), and sequence analyses revealed that it is a member of the ubiquitously distributed group of nucleotide pyrophosphatases designated as "nudix" hydrolases. Insertional mutagenesis experiments leading to the inactivation of the ASPPase encoding gene, aspP, produced cells with marginally low enzymatic activities and higher glycogen content than wild-type bacteria. aspP was cloned into an expression vector and introduced into E. coli. Transformed cells were shown to contain a dramatically reduced amount of glycogen, as compared with the untransformed bacteria. No pleiotropic changes in the bacterial growth occurred in both the aspP-overexpressing and aspP-deficient strains. The overall results pinpoint the reaction catalyzed by ASPPase as a potential step of regulating glycogen biosynthesis in E. coli.

Influence of age and ovariectomy on the hypocholesterolemic effects of dietary taurine in rats fed a cholesterol-free diet

The effects of taurine feeding on plasma cholesterol concentrations and fecal bile acid excretion were examined in young and aged male and female rats (5 weeks and 10 months old respectively), the latter either ovariectomized (ovx) or sham-operated. The rats were fed a cholesterol-free diet (C diet) or a cholesterol-free taurine-supplemented diet (T diet; C + 5% taurine) for 28 days. In males, plasma cholesterol concentrations and fecal bile acid excretion were higher and lower, respectively, in aged rats than in young rats, but were not affected by feeding with the T diet. In female rats, plasma cholesterol concentrations were higher in aged rats than in young rats and higher in ovx-rats than in sham-operated rats. In contrast to male rats, plasma cholesterol concentrations were lower in female rats fed the T diet than in those fed the C diet. Plasma cholesterol concentrations were increased in aged ovx-rats, but decreased by feeding with the T diet. Fecal bile acid excretion was higher in rats fed the T diet than in those fed the C diet. Thus, these data indicate that the hypocholesterolemic effect of taurine is greater in aged rats than in young rats.

ATP-regenerating system in the cilia of Paramecium caudatum

The energy supply for eukaryotic ciliary and flagellar movement is thought to be maintained by ATP-regenerating enzymes such as adenylate kinase, creatine kinase and arginine kinase. In this study, the energy-supplying system for the ciliary movement of Paramecium caudatum was examined. Arginine kinase and adenylate kinase activities were detected in the cilia. To demonstrate that phosphoarginine satisfactorily supplies high-energy phosphate compounds into the narrow ciliary space, we prepared an intact ciliated cortical sheet from live Paramecium caudatum. These cortical sheets, with an intact ciliary membrane, produced a half-closed system in which each cilium was covered with a ciliary membrane with an opening to the cell body. Ciliary beating on the intact cortical sheets was induced by perfusing not only ATP but also ADP. Addition of phosphoarginine (0.2 mmol l(−1)) increased the beat frequency. A further increase in beat frequency was observed in 0.4 mmol l(−1) phosphoarginine, and this was enhanced when the cilia were reactivated with relatively low concentrations of ATP. We have demonstrated that phosphoarginine supplies energy as a ‘phosphagen’ for ciliary beating in Paramecium caudatum, suggesting that phosphoarginine functions not only as a reservoir of energy but also as a transporter of energy in these continuously energy-consuming circumstances. http://www.biologists.com/JEB/movies/jeb3123.html

Two isoforms of a nucleotide-sugar pyrophosphatase/phosphodiesterase from barley leaves (Hordeum vulgare L.) are distinct oligomers of HvGLP1, a germin-like protein

Two isoforms of ADPglucose pyrophosphatase/phosphodiesterase (AGPPase) have been characterized using barley leaves (Hordeum vulgare L.). Whilst one of the isoforms, designated as soluble AGPPase1 (SAGPPase1), is soluble in low ionic strength buffers, the other, SAGPPase2, is extractable using cell wall hydrolytic enzymes or high salt concentration solutions, thus indicating that it is adventitiously bound to the cell wall. Both AGPPase isoforms are highly resistant to SDS, this characteristic being utilized to purify them to homogeneity after zymographic detection of AGPPase activity in SDS-containing gels. N-terminal and internal amino acid sequencing analyses revealed that both SAGPPase1 and SAGPPase2 are distinct oligomers of the previously designated HvGLP1, which is a member of the ubiquitously distributed group of proteins of unknown function designated as germin-like proteins (GLPs).

The expression of a novel natural killer inhibitory molecule, Cho-1, on the chorionic cytotrophoblast cells of successful pregnancy, but not of spontaneous abortion

The regulatory mechanism of the recognition and cytotoxicity by natural killer (NK) cells in placental tissue remains unclarified. Previous reports indicated that monoclonal antibody Cho-1-defined molecule (Cho-1 molecule) may act as the negative regulator in the cytotoxicity by human NK cells. The Cho-1 molecule is composed of non-covalently associated cell surface molecules of approximately 200 kDa and 40 kDa. In the present study we analyzed the expression of this novel molecule in extravillous cytotrophoblast cells, which are presumed to be exposed to the cytotoxic action by maternal NK cells, from clinical cases of successful pregnancy and spontaneous abortion. By using monoclonal antibody Cho-1, our immunohistochemical data indicated that the Cho-1 molecule is clearly expressed in the cytotrophoblast cells of the early phase of successful pregnancy, but only weakly expressed in those from spontaneous abortion. The cytotrophoblast cells in the late phase (9-10 months) of pregnancy also expressed this molecule. Fluorescence-activated cell sorter analysis also showed that it is expressed on the cytotrophoblast cell surface of successful pregnancy but not on that of spontaneous abortion, suggesting that Cho-1 antigen may act as a negative regulator of the cytotoxicity by NK cells in successful pregnancy of the fetus.

Distinct isoforms of ADPglucose pyrophosphatase and ADPglucose pyrophosphorylase occur in the suspension-cultured cells of sycamore (Acer pseudoplatanus L.)

The intracellular localizations of ADPglucose pyrophosphatase (AGPPase) and ADPglucose pyrophosphorylase (AGPase) have been studied using protoplasts prepared from suspension-cultured cells of sycamore (Acer pseudoplatanus L.). Subcellular fractionation studies revealed that all the AGPPase present in the protoplasts is associated with amyloplasts, whereas more than 60% of AGPase is in the extraplastidial compartment. Immunoblots of amyloplast- and extraplastid-enriched extracts further confirmed that AGPase is located mainly outside the amyloplast. Experiments carried out to identify possible different isoforms of AGPPase in the amyloplast revealed the presence of soluble and starch granule-bound isoforms. We thus propose that ADPglucose levels linked to starch biosynthesis in sycamore cells are controlled by enzymatic reactions catalyzing the synthesis and breakdown of ADPglucose, which take place both inside and outside the amyloplast.

Excitatory cortical inputs to pallidal neurons via the subthalamic nucleus in the monkey

How the motor-related cortical areas modulate the activity of the output nuclei of the basal ganglia is an important issue for understanding the mechanisms of motor control by the basal ganglia. In the present study, by using awake monkeys, the polysynaptic effects of electrical stimulation in the forelimb regions of the primary motor and primary somatosensory cortices on the activity of globus pallidus (GP) neurons, especially mediated by the subthalamic nucleus (STN), have been characterized. Cortical stimulation induced an early, short-latency excitation followed by an inhibition and a late excitation in neurons of both the external and internal segments of the GP. It also induced an early, short-latency excitation followed by a late excitation and an inhibition in STN neurons. The early excitation in STN neurons preceded that in GP neurons. Blockade of STN neuronal activity by muscimol (GABA(A) receptor agonist) injection resulted in abolishment of both the early and late excitations evoked in GP neurons by cortical stimulation. At the same time, the spontaneous discharge rate of GP neurons decreased, pauses between the groups of spikes of GP neurons became prominent, and the firing pattern became regular. Injection of (+/-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) [N-methyl-D-aspartate (NMDA) receptor antagonist], but not 1,2,3, 4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide disodium [NBQX (non-NMDA receptor antagonist)], into the STN attenuated the early and late excitations in GP neurons, suggesting that cortico-subthalamic transmission is mediated mainly by NMDA receptors. Interference with the pallido-subthalamic transmission by bicuculline (GABA(A) receptor antagonist) injection into the STN made the inhibition distinct without affecting the early excitation. The present results indicate that the cortico-subthalamo-pallidal pathway conveys powerful excitatory effects from the motor-related cortical areas to the GP with shorter conduction time than the effects conveyed through the striatum.

Estimation of stature from the skeletal reconstruction of an immature Neandertal from Dederiyeh cave, Syria

Skeletal reconstruction of a child Neandertal unearthed at Dederiyeh Cave, Syria in 1993, is undertaken and the acquired stature discussed. Although the skeletal remains were well preserved, the reconstruction required several assumptions to be made because of the immature status of the specimen. The assumptions were mainly concerned with distances between bones in the inter-vertebral spaces and in the joints of the hip, knee, and ankle. These were estimated from X-ray films of modern children and data from previous studies. Stature was directly measured on the reconstruction, and found to be 79.2 cm. After corrections for soft tissue thickness and shrinkage of the casts, the stature became 81.7 cm. This estimate is consistent with estimates based on regression equations of long bone lengths, especially from those of the lower extremity. In comparison with longitudinal data for white American boys, the assessment of stature for Dederiyeh varied according to the estimated age. For a younger estimated age, the stature falls in the lower half of the white American range of variation, but with an older estimated age, it falls below the lower limit of the range of variation. Other immature Neandertals including two European specimens, Roc de Marsal and La Ferrassie 6, fall below the lower limit of the 5th to 95th percentile range based on the estimated statures from their long bone lengths. More comprehensive age assessment covering both fossil and modern humans is required before accurate conclusions in relation to Neandertal growth can be drawn.

A cortical motor region that represents the cutaneous back muscles in the macaque monkey

A cortical motor region that represented the cutaneous muscles on the back was identified on the medial wall of the frontal lobe in the macaque monkey. In this region, neurons responded to somatosensory stimuli such as light touch or squeezing of the back skin, and intracortical microstimulation elicited contraction of the back skin. Such a region was located primarily on the dorsal bank of the cingulate sulcus, corresponding to the dorsal cingulate motor area.

Improved liquid chromatographic separation of different proteins by designing functional surfaces of cattle bone-originated apatite

Spherical particles of cattle bone-originated hydroxyapatite (r-HAp) were prepared by dissolution-precipitation, spray-drying using a two fluid-nozzle apparatus, and subsequent heat treatment. The product had effective pore structures for liquid chromatographic separation of albumin, myoglobin, ribonuclease, lysozyme and cytochrome c. The activated surfaces of the r-HAp particles were easily prepared with desired proportions of P- and C-sites and appropriate acid-basic strength for selective protein adsorption by optimizing the synthesis conditions. Liquid chromatography columns packed with the particles exhibited high resolution and durability in protein separation, reflecting stable distribution of pore size.

Bleeding through the fiber interstices of a knitted dacron graft 12 years after its implantation: report of a case

We present herein the case of a 65-year-old man who suddenly developed fresh perigraft bleeding into the space between a knitted Dacron bifurcated graft and the aneurysmal sac, 12 years after undergoing graft replacement. Intraoperative findings did not show Dacron fiber degeneration at the nonanastomotic sites or a pseudoaneurysm at the anastomotic site. Widened Dacron fiber interstices resulting from graft dilation without sufficient graft healing was thought to have caused delayed hemorrhage through the macroscopically intact graft material, followed by massive clot retention between the graft and the aneurysmal sac. This case report serves to demonstrate that careful long-term follow-up is essential for patients who have undergone vascular graft replacement.

Corticostriatal and corticosubthalamic input zones from the presupplementary motor area in the macaque monkey: comparison with the input zones from the supplementary motor area

The presupplementary motor area (pre-SMA) is a cortical motor-related area which lies in the medial wall of the frontal lobe, immediately anterior to the supplementary motor area (SMA). This area has been considered to participate in the control of complex forelimb movements in a way different from the SMA. In an attempt to analyze the patterns of projections from the pre-SMA to the basal ganglia, we examined the distributions of pre-SMA inputs in the striatum and the subthalamic nucleus and compared them with the SMA input distributions. To detect morphologically the terminal fields from the pre-SMA and the forelimb region of the SMA, anterograde tracers were injected into such areas that had been identified electrophysiologically in the macaque monkey. Corticostriatal inputs from the pre-SMA were distributed mainly in the striatal cell bridges connecting the rostral aspects of the caudate nucleus and the putamen, as well as in their neighboring striatal portions. These input zones were located, with no substantial overlap, rostral to corticostriatal input zones from the SMA forelimb region. Corticosubthalamic input zones from the pre-SMA were almost localized in the medial aspect of the nucleus, where corticosubthalamic inputs from the SMA forelimb region were also distributed predominantly. However, the major terminal fields from the pre-SMA were centered ventrally to those from the SMA. The present results indicate that the corticostriatal and corticosubthalamic input zones from the pre-SMA appear to be segregated from the SMA-derived input zones. This implies the possibility of parallel processing of motor information from the pre-SMA and SMA in the cortico-basal ganglia circuit.

Corticostriatal projections from distal and proximal forelimb representations of the monkey primary motor cortex

Corticostriatal projections from one distal and two proximal subregions in the forelimb representation of the primary motor cortex (MI) were examined in the macaque monkey. The distal and proximal subregions in the anterior bank of the central sulcus (distal and proximal-bank subregions) and the proximal subregion in the surface of the precentral gyrus (proximal-surface subregion) of the MI were identified using intracortical microstimulation. Different anterograde tracers were then injected into two of these three forelimb subregions of the MI. In the ipsilateral putamen, the distribution areas of corticostriatal fibers from the distal, proximal-bank and proximal-surface subregions were arranged from ventrolateral to dorsomedial in this order. These corticostriatal input zones were largely segregated from one another.