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.