Biaxial residual stress states of plasma-sprayed hydroxyapatite coatings on titanium alloy substrate

Biaxial residual stress states of plasma-sprayed hydroxyapatite coatings (HACs) on titanium alloy substrate as a function of plasma power, powder feed rate and coating thickness were studied by X-ray 'sin2 psi' method. The Young's modulus of hydroxyapatite (HA), required for the stress analysis, was measured from the separated free coating by three-point bending test method. It was found that the directions of principal stresses were in proximity to and perpendicular to the spraying direction. The measured Young's moduli of HACs were much lower than the theoretical value reported. The denser, well-melted HAC exhibited a higher residual stress, as compared with the less dense, poor-melting HAC. The denser coatings could be effected by higher plasma power and lower powder feed rate. Significantly, the thicker 200 microm HAC exhibited higher residual stress than that of the thinner 50 microm HAC. The implications of residual stress in HAC for biomaterials are discussed in detail.

Finite element analysis of thermo-debonding mechanism in dental composites

Finite element method (FEM) has been extensively used for evaluating interfacial status inside biomaterials. This study using FEM was designed to evaluate the thermal stress behavior of a filler-matrix interface. The results were then compared to those of a previous study obtained by a laser thermoacoustic technique (LTAT). The experimental systems (75/25 Bis-GMA/TEGDMA resin reinforced with 0, 25, 50, and 75 wt% 8-microm silanized/unsilanized BaSiO6) as used in the previous study were modeled in this study. The established finite element models were based on coefficient of thermal expansion (CTE) Mismatch Phenomenon. The mechanical properties of the silane coupling agent, such as elastic modulus and thermal expansion coefficient used in the silanized model, were assumed to have optimal heat flux transfer. A third (imaginary) material was proposed to block the transfer of thermal stress between the filler and matrix in the unsilanized model. The thermal load simulation was based on steady-state thermal analysis. The results showed that: (1) The strain energy and interfacial shearing stress calculated from FEM validate the results from the previous LTAT study. (2) Comparing the stress distribution of silanized and unsilanized FEM models, the acoustic signals in LTAT study are mainly derived from debonding of the filler-matrix interface of silanized specimens, and from the matrix area of unsilanized specimens. Based on results to date, we conclude that the finite element method may be a powerful tool for exploring thermoacoustic mechanisms of dental composites.

PNRC: a proline-rich nuclear receptor coregulatory protein that modulates transcriptional activation of multiple nuclear receptors including orphan receptors SF1 (steroidogenic factor 1) and ERRalpha1 (estrogen related receptor alpha-1)

PNRC (proline-rich nuclear receptor coregulatory protein) was identified using bovine SF1 (steroidogenic factor 1) as the bait in a yeast two-hybrid screening of a human mammary gland cDNA expression library. PNRC is unique in that it has a molecular mass of 35 kDa, significantly smaller than most of the coregulatory proteins reported so far, and it is proline-rich. PNRC's nuclear localization was demonstrated by immunofluorescence and Western blot analyses. In the yeast two-hybrid assays, PNRC interacted with the orphan receptors SF1 and ERRalpha1 in a ligand-independent manner. PNRC was also found to interact with the ligand-binding domains of all the nuclear receptors tested including estrogen receptor (ER), androgen receptor (AR), glucocorticoid receptor (GR), progesterone receptor (PR), thyroid hormone receptor (TR), retinoic acid receptor (RAR), and retinoid X receptor (RXR) in a ligand-dependent manner. Functional AF2 domain is required for nuclear receptors to bind to PNRC. Furthermore, in vitro glutathione-S-transferase pull-down assay was performed to demonstrate a direct contact between PNRC and nuclear receptors such as SF1. Coimmunoprecipitation experiment using Hela cells that express PNRC and ER was performed to confirm the interaction of PNRC and nuclear receptors in vivo in a ligand-dependent manner. PNRC was found to function as a coactivator to enhance the transcriptional activation mediated by SF1, ERR1 (estrogen related receptor alpha-1), PR, and TR. By examining a series of deletion mutants of PNRC using the yeast two-hybrid assay, a 23-amino acid (aa) sequence in the carboxy-terminal region, aa 278-300, was shown to be critical and sufficient for the interaction with nuclear receptors. This region is proline rich and contains a SH3-binding motif, S-D-P-P-S-P-S. Results from the mutagenesis study demonstrated that the two conserved proline (P) residues in this motif are crucial for PNRC to interact with the nuclear receptors. The exact 23-amino acid sequence was also found in another protein isolated from the same yeast two-hybrid screening study. These two proteins belong to a new family of nuclear receptor coregulatory proteins.

Batch and continuous cultivation of Anaerobiospirillum succiniciproducens for the production of succinic acid from whey

Batch and continuous cultivation of Anaerobiospirillum succiniciproducens were systematically studied for the production of succinic acid from whey. Addition of 2.5 g l(-1) yeast extract and 2.5 g l(-1) polypeptone per 10 g l(-1) whey was most effective for succinic acid production from both treated and nontreated whey. When 20 g l(-1) nontreated whey and 7 g l(-1) glucose were used as cosubstrates, the yield and productivity of succinic acid reached at the end of fermentation were 95% and 0.46 g (1 h)(-1), respectively. These values were higher than those obtained using nontreated whey alone [93% and 0.24 g (1 h)(-1) for 20 g l(-1) whey]. Continuous fermentation of A. succiniciproducens at an optimal dilution rate resulted in the production of succinic acid with high productivity [1.35 g (1 h)(-1)], high conversion yield (93%), and higher ratio of succinic acid to acetic acid (5.1:1) from nontreated whey.

Suramin protects the murine motor nerves from the toxic effects of presynaptic Ca(2+) channel inhibitors

The purpose of this study is to investigate whether suramin is capable of preventing the neurotoxic effects of Ca(2+) channel inhibitors at the presynaptic sites. Mouse diaphragm and triangularis sterni preparations were used for this study in order to measure the muscle tension and nerve terminal Ca(2+) current, respectively. Both omega-conotoxin MVIIC and omega-agatoxin IVA markedly inhibit the nerve-evoked muscle contractions as well as the nerve terminal Ca(2+) current respectively. Pretreatment with suramin (0.3 mM) significantly reduced the inhibitory effect of nerve-evoked muscle contractions and Ca(2+) current induced by either omega-conotoxin MVIIC or omega-agatoxin IVA but not that induced by the non-selective Ca(2+) channel blocker, Cd(2+). Neither suramin nor Ca(2+)-channel toxins significantly affect Na(+)- and K(+) currents of the nerve terminals. These findings indicate that suramin selectively interferes the action of presynaptic Ca(2+) channel neurotoxins and thus reduces their depressant effects on the muscle contractions. The implication of these findings is that suramin and its derivatives may potentially become useful agents in management of intoxication of Ca(2+) channel neurotoxins.

N-terminal targeting of guanine nucleotide exchange factors (GEF) for ADP ribosylation factors (ARF) to the Golgi

B2-1 (cytohesin-1) is a member of a group of proteins (including ARNO and ARNO3) that are all of similar size and domain composition. The three proteins contain an N-terminal coiled-coil domain, followed by a Sec7 and a pleckstrin homology (PH) domain. While it is well established that the Sec7 domain functions as a guanine nucleotide exchange factor (GEF) for ADP-ribosylation factors (ARFs) and the PH domain anchors the proteins to membrane phosphoinositols, the function of the N-terminal domain is unknown. Here we show that the N terminus of B2-1 (residues 1–54) is necessary and sufficient to target the protein to the Golgi. The Sec7+PH domains of B2-1 (residues 55–398) are not sufficient for Golgi localization. Further deletion analysis and point mutagenesis indicate that the coiled-coil domain within the N terminus is responsible for Golgi targeting. Furthermore, ARNO and ARNO3 N termini also have the same capability of targeting to the Golgi. We conclude that the N-terminal, (α)-helical, coiled-coil domain is used to target this family of proteins to the Golgi complex.

Comparing MR imaging and CT in the staging of gastric carcinoma

OBJECTIVE

The purpose of this study was to assess the usefulness of breath-hold two-dimensional (2D) fast low-angle shot (FLASH) and T2-weighted turbo spin-echo fast MR imaging compared with helical CT in the staging of gastric carcinoma.

SUBJECTS AND METHODS

Thirty patients with gastric carcinoma underwent preoperative MR imaging and helical CT. MR imaging at 1.5 T was performed immediately after the intramuscular injection of scopolamine and the oral administration of water or effervescent granules. Breath-hold 2D FLASH T1-weighted images in all three planes, turbo spin-echo T2-weighted axial images, and gadolinium-enhanced fat-suppressed 2D FLASH axial images were included. Helical CT was performed 60 sec after initiation of i.v. contrast medium injection (2.5-3 ml/sec). Two groups of two radiologists each independently analyzed the MR and helical CT findings, and these results were compared with the pathologic findings.

RESULTS

For T staging, MR imaging accuracy was higher than that of helical CT (73.3% and 66.7%, respectively); however, the accuracies of the two methods were not significantly different from each other (McNemar test, p > 0.05). Overstaging was noted in 6.7% of cases with MR imaging and 10% with helical CT. Understaging was noted in 20% of cases with MR imaging and 23.3% with helical CT. For N staging, the accuracies of MR imaging and helical CT were 55% and 58.6%, respectively, with no statistical significance (overstaging, 10% and 6.9%; understaging, 34.5% and 34.5%, respectively).

CONCLUSION

MR imaging was comparable to helical CT in the T and N staging of gastric cancer.

Use of PCR with universal primers and restriction endonuclease digestions for detection and identification of common bacterial pathogens in cerebrospinal fluid

We have designed a universal PCR capable of amplifying a portion of the 16S rRNA gene of eubacteria, including Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae, Enterococcus faecium, Enterococcus faecalis, Mycobacterium tuberculosis, Legionella pneumophila, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Enterobacter cloacae, Pseudomonas aeruginosa, Acinetobacter baumannii, Proteus mirabilis, Haemophilus influenzae, and Neisseria meningitidis. The sizes of the amplified products from various bacteria were the same (996 bp), but the restriction patterns of most PCR products generated by HaeIII digestion were different. PCR products from S. aureus and S. epidermidis could not be digested by HaeIII but yielded different patterns when they were digested with MnlI. PCR products from S. pneumoniae, E. faecium, and E. faecalis yielded the same HaeIII digestion pattern but could be differentiated by AluI digestion. PCR products from E. coli, K. pneumoniae, S. marcescens, and E. cloacae also had the same HaeIII digestion pattern but had different patterns when digested with DdeI or BstBI. This universal PCR could detect as few as 10 E. coli or 250 S. aureus organisms. Compared with culture, the sensitivity of this universal PCR for detection and identification of bacteria directly from 150 cerebrospinal fluids was 92.3%. These results suggest that this universal PCR coupled with restriction enzyme analysis can be used to detect and identify bacterial pathogens in clinical specimens.

Economic considerations in the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by bacterial fermentation

The process for the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB/V)] by bacterial fermentation and its recovery was analysed. The effects of various factors such as P(3HB/V) content, P(3HB/V) productivity, P(3HB/V) yield and 3-hydroxyvalerate (3HV) fraction in P(3HB/V) on the production cost of P(3HB/V) were examined. The increase in the 3HV yield on a carbon source did not significantly decrease the production cost when the 3HV fraction was 10 mol%, because the cost of the carbon substrate for 3HV was relatively small in terms of the total cost. However, at a 3HV fraction of 30 mol%, the 3HV yield on a carbon source had a significant effect on the total P(3HB/V) production cost. The production cost of P(3HB/V) increased linearly with the increase in the 3HV fraction in P(3HB/V).

Ultrasound and other imaging technologies in the intensive care unit

As technology advances, more imaging and procedures are performed at the bedside on critically ill patients in ICUs, thereby eliminating the risks of transporting patients. These imaging techniques can serve as diagnostic and therapeutic tools in treating the acute and chronic consequences of injured, critically ill patients. One area of growth is ultrasonography. Critical care applications of ultrasonography are expanding, and the learning curve of surgeons and intensivists performing some of these studies is improving. Ultrasonography can supplement physical examination and provide useful "real-time" information on nearly every body cavity. Other imaging technology is also available in a portable form, enabling imaging directly at the bedside. Images are now becoming readily and easily available with the advancement of teleradiology. Some of the imaging modalities are still in development, and their clinical effectiveness is being studied. In the future, more uses of these various imaging technologies may become evident and cost-effective.

Efficient secretory production of alkaline phosphatase by high cell density culture of recombinant Escherichia coli using the Bacillus sp. endoxylanase signal sequence

New secretion vectors containing the Bacillus sp. endoxylanase signal sequence were constructed for the secretory production of recombinant proteins in Escherichia coli. The E. coli alkaline phosphatase structural gene fused to the endoxylanase signal sequence was expressed from the trc promoter in various E. coli strains by induction with IPTG. Among those tested, E. coli HB101 showed the highest efficiency of secretion (up to 25.3% of total proteins). When cells were induced with 1 mM IPTG, most of the secreted alkaline phosphatase formed inclusion bodies in the periplasm. However, alkaline phosphatase could be produced as a soluble form without reduction of expression level by inducing with less (0.01 mM) IPTG, and greater than 90% of alkaline phosphatase could be recovered from the periplasm by the simple osmotic shock method. Fed-batch cultures were carried out to examine the possibility of secretory protein production at high cell density. Up to 5.2 g/l soluble alkaline phosphatase could be produced in the periplasm by the pH-stat fed-batch cultivation of E. coli HB101 harboring pTrcS1PhoA. These results demonstrate the possibility of efficient secretory production of recombinant proteins in E. coli by high cell density cultivation.

Adenosine triphosphate-induced heterologous desensitization of endothelin-1- and glutamate-evoked calcium increases in cultured rat cortical astrocytes

In rat cortical astrocytes, we investigated the occurrence of cross-talks between purinoceptor and endothelin (ET) receptor, or glutamate receptor. The treatments of adenosine triphosphate (ATP), ET-1, and glutamate induced the increase of intracellular calcium level in the astrocytes. In repetitive additions of ATP to astrocytes, the second application of ATP exhibited comparable amplitude of calcium response, but the stimulation with ATP completely blocked subsequent ET-1- or glutamate-evoked calcium responses showing complete heterologous desensitization. In contrast, ET-1 and glutamate failed to desensitize the response elicited by ATP. Preincubation with sphingosine, a protein kinase C (PKC) inhibitor, reversed the ATP-induced desensitization of ET-1- and glutamate-evoked calcium responses. Taken together, these results demonstrate the resistance of purinoceptor to homologous desensitization, and unidirectional desensitization between ATP and other receptors such as ET and glutamate receptors, suggesting a dominant role of purinoceptor in modulating calcium signal of astrocytes.

Direct activation of capsaicin receptors by products of lipoxygenases: endogenous capsaicin-like substances

Capsaicin, a pungent ingredient of hot peppers, causes excitation of small sensory neurons, and thereby produces severe pain. A nonselective cation channel activated by capsaicin has been identified in sensory neurons and a cDNA encoding the channel has been cloned recently. However, an endogenous activator of the receptor has not yet been found. In this study, we show that several products of lipoxygenases directly activate the capsaicin-activated channel in isolated membrane patches of sensory neurons. Among them, 12- and 15-(S)-hydroperoxyeicosatetraenoic acids, 5- and 15-(S)-hydroxyeicosatetraenoic acids, and leukotriene B(4) possessed the highest potency. The eicosanoids also activated the cloned capsaicin receptor (VR1) expressed in HEK cells. Prostaglandins and unsaturated fatty acids failed to activate the channel. These results suggest a novel signaling mechanism underlying the pain sensory transduction.

Production of medium-chain-length polyhydroxyalkanoates by high-cell-density cultivation of Pseudomonas putida under phosphorus limitation

High-cell-density fed-batch cultures of Pseudomonas putida were carried out for the production of medium-chain-length polyhydroxyalkanoates (PHAs) using oleic acid as a carbon source. By employing an optimal feeding strategy without the limitation of any nutrient, a high cell concentration of 173 g/L was achieved, but the PHA concentration and PHA content were only 32.3 g/L and 18.7 wt%, respectively. To increase the PHA concentration and content, phosphorus limitation was applied during fed-bath culture by reducing the initial KH(2)PO(4) concentration. When the initial KH(2)PO(4) concentration was reduced to 4 g/L, cell concentration, PHA concentration, and PHA content obtained in 38 h were 141 g/L, 72. 6 g/L, and 51.4 wt%, respectively, resulting in a high productivity of 1.91 g PHA/L per hour.

Molecular cloning of a soybean class III beta-1,3-glucanase gene that is regulated both developmentally and in response to pathogen infection

We isolated and characterized a soybean gene (SGN1) encoding a basic beta-1,3-glucanase that is a plant class III isoform of beta-1,3-glucanase. The deduced amino acid sequence of the SGN1 gene is similar to that of the PR-Q'b gene, the basic class III beta-1,3-glucanase of tomato. Based on RNA blot hybridization, SGN1 gene expression was detected in all tissues of 4-day old seedlings, but it was present only in root tissue of 30-day old plants. GUS expression analysis carried out in transgenic tobacco plants harboring a SGN1::GUS reporter gene revealed the same expression pattern. Furthermore, the expression of SGN1 was strongly induced by a variety of defense-related signals, such as treatment with H(2)O(2), wounding, or treatment with fungal elicitor prepared from Phytophthora spp as well as inoculation with Pseudomonas syringae. However, the expression level of SGN1 was hardly induced with jasmonate, ethephon and salicylate. Overall the results suggest that the SGN1 may play a role in both plant development and plant defense against pathogen attack.

B2-1, a Sec7- and pleckstrin homology domain-containing protein, localizes to the Golgi complex

B2-1 is a human protein that contains both a Sec7 and a pleckstrin homology domain. The yeast Sec7 protein was previously shown to be involved in vesicle formation in the Golgi and endoplasmic reticulum. Recently, several groups have shown that B2-1 and highly similar proteins (e.g., ARNO, ARNO3) have varied cellular functions and subcellular locations. One of these is an association of the B2-1 Sec7 domain with the plasma membrane, binding to the cytoplasmic portion of the integrin beta2 chain (CD18) and is postulated to be involved in inside-out signaling. Other groups have shown that B2-1 and these related proteins are guanine nucleotide-exchange factors that act upon ADP ribosylation factors (ARFs) and are localized to the Golgi or plasma membrane. Here we report the subcellular localization of B2-1 protein. Interestingly, B2-1 does not localize to the plasma membrane but rather associates with a distinct Golgi complex compartment. B2-1's distribution can be disrupted by brefeldin A, a drug that rapidly disrupts the Golgi apparatus by inhibiting ARF activity. Furthermore, transient transfection of GFP-tagged B2-1 shows Golgi complex targeting. Excessive overexpression of transfected B2-1 causes partial Golgi dispersion.

Finite element analysis of brain contusion: an indirect impact study

The mechanism of brain contusion has been investigated using a series of three-dimensional (3D) finite element analyses. A head injury model was used to simulate forward and backward rotation around the upper cervical vertebra. Intracranial pressure and shear stress responses were calculated and compared. The results obtained with this model support the predictions of cavitation theory that a pressure gradient develops in the brain during indirect impact. Contrecoup pressure-time histories in the parasagittal plane demonstrated that an indirect impact induced a smaller intracranial pressure (-53.7 kPa for backward rotation, and -65.5 kPa for forward rotation) than that caused by a direct impact. In addition, negative pressures induced by indirect impact to the head were not high enough to form cavitation bubbles, which can damage the brain tissue. Simulations predicted that a decrease in skull deformation had a large effect in reducing the intracranial pressure. However, the areas of high shear stress concentration were consistent with those of clinical observations. The findings of this study suggest that shear strain theory appears to better account for the clinical findings in head injury when the head is subjected to an indirect impact.

Monitoring CD8 T cell responses to NY-ESO-1: correlation of humoral and cellular immune responses

NY-ESO-1, a member of the cancer-testis family of antigens, is expressed in a subset of a broad range of different human tumor types. Patients with advanced NY-ESO-1-expressing tumors frequently develop humoral immunity to NY-ESO-1, and three HLA A2-restricted peptides were defined previously as targets for cytotoxic CD8(+) T cells in a melanoma patient with NY-ESO-1 antibody. The objectives of the present study were (i) to develop enzyme-linked immunospot (ELISPOT) and tetramer assays to measure CD8(+) T cell responses to NY-ESO-1, (ii) to determine the frequency of CD8(+) T cell responses to NY-ESO-1 in a series of HLA-A2 patients with NY-ESO-1 expressing tumors, (iii) to determine the relation between CD8(+) T cell and humoral immune responses to NY-ESO-1, and (iv) to compare results of NY-ESO-1 ELISPOT assays performed independently in two laboratories with T cells from the same patients. NY-ESO-1 ELISPOT and tetramer assays with excellent sensitivity, specificity, and reproducibility have been developed and found to correlate with cytotoxicity assays. CD8(+) T cell responses to HLA-A2-restricted NY-ESO-1 peptides were detected in 10 of 11 patients with NY-ESO-1 antibody, but not in patients lacking antibody or in patients with NY-ESO-1-negative tumors. The results of ELISPOT assays were concordant in the two laboratories, providing the basis for standardized monitoring of T cell responses in patients receiving NY-ESO-1 vaccines.

The whole is not the simple sum of its parts in calmodulin from S. cerevisiae

Calmodulin is an essential Ca(2+)-binding protein involved in a multitude of cellular processes. The calmodulin sequence is highly conserved among all eukaryotic species; calmodulin from the yeast S. cerevisiae (yCaM) is the most divergent form, while still sharing 60% sequence identity with vertebrate calmodulin (vCaM). Although yCaM can be functionally substituted by vCaM in vivo, the two calmodulin proteins possess significantly different Ca(2+)-binding properties as well as abilities to activate vertebrate target enzymes in vitro. In addition, it has been observed that certain properties of the N-terminal and C-terminal domains of Ca(2+)-yCaM differ depending on whether they are in the context of the whole protein or isolated as half-molecule fragments. To investigate the structural basis for these differing properties, we have undertaken nuclear magnetic resonance (NMR) studies on yCaM and the two half-molecule fragments representing its two individual domains, yTr1(residues 1-76) and yTr2 (residues 75-146). We present direct evidence that the two domains of Ca(2+)-yCaM interact via their exposed hydrophobic surfaces. Thus, the Ca(2+)-bound form of yCaM exists in a novel compact structure in direct contrast to the well-established structure of Ca(2+)-vCaM comprised of two independent globular domains.

Gene expression of flap endonuclease-1 during cell proliferation and differentiation

It has been shown that flap endonuclease-1 (FEN-1), a structure-specific nuclease, acts on the removal of RNA primers during Okazaki fragment maturation in DNA synthesis. To study whether the gene expression of FEN-1 is inducible during cell proliferation, we analyzed the FEN-1 mRNA levels in actively growing cells and non-growing cells. The gene expression of FEN-1 was higher in mitotic cells than in resting cells, and was markedly decreased, especially, when terminal differentiation was induced in promyelocytic leukemia cells (HL-60 cells). The decline correlated substantially with the ceasing of DNA synthesis. In the examination of tissue-specific gene expression, the human testis, spleen, thymus and mucosal lining of colon tissues expressed this gene actively, whereas the prostate, ovary, small intestine and peripheral blood leukocyte hardly expressed it. In addition, FEN-1 was co-localized with the proliferating cell nuclear antigen (PCNA) in young rat kidney according to immunohistochemistry. These findings suggest that FEN-1 gene expression is inducible during cell proliferation for DNA synthesis, and is down-regulated during cell differentiation.

Membrane perturbation by mastoparan 7 elicits a broad alteration in lipid composition of L1210 cells

Mastoparan 7 (Mas-7), an amphiphilic peptide possessing membrane perturbing activity, has been known to selectively stimulate some lipases. To examine changes in the lipid composition induced by Mas-7, we carried out systemic lipid analysis of L1210 cells after Mas-7 treatment. The total lipid was determined by HPLC, gas-liquid chromatography, and electrospray ionization mass spectrometry in conjunction with differential radiolabelling with [(32)P]orthophosphate, [(3)H]myristic acid, and [(3)H]arachidonic acid. The lipid analysis revealed multiple changes in more than 10 lipid classes. Free fatty acids (FFAs) and phosphatidylethanol (PEt), the phospholipase D product in the presence of ethanol, were increased significantly and phosphatidylcholine (PC) was decreased. Digitonin, a membrane permeabilizing reagent, similarly affected the lipid composition of L1210. The FFA released showed a very broad distribution of saturated, monounsaturated, and polyunsaturated fatty acids, implying that phospholipase A(2) alone could not account for all of the FFAs released. By comparing the molecular species of PEt with those of endogenous PC, we showed that phospholipase D in L1210 cells appeared to act selectively on diacyl-PC. The perturbation-induced alterations in the lipid composition brought about by Mas-7 might play a crucial role in the physiology of the affected cells.

A cell adhesion protein from the crayfish Pacifastacus leniusculus, a serine proteinase homologue similar to Drosophila masquerade

A cDNA encoding a protein resembling masquerade, a serine proteinase homologue expressed during embryogenesis, larval, and pupal development in Drosophila melanogaster, was identified in hemocytes of the adult freshwater crayfish, Pacifastacus leniusculus. The crayfish protein is similar to Drosophila masquerade in the following aspects: (a) overall sequence of the serine proteinase domain, such as the position of three putative disulfide bridges, glycine in the place of the catalytic serine residue, and the presence of a substrate-lining pocket typical for trypsins; (b) the presence of several copies of a disulfide-knotted motif in the putative propeptide. This masquerade-like protein is cleaved into a 27-kDa fragment, which could be detected by immunoblot analysis using an affinity-purified antibody against a synthetic peptide in the C-terminal domain of the protein. The 27-kDa protein could be immunoaffinity-purified from hemocyte lysate supernatant and exhibited cell adhesion activity in vitro, indicating that the C-terminal domain of the crayfish masquerade-like protein mediates cell adhesion.

In vivo and in vitro natural frequency analysis of periodontal conditions: an innovative method

BACKGROUND

When measuring periodontal disease, various types of equipment for making objective measurements of tooth mobility have been proposed. However, these devices and methodology are insufficient in terms of reliability. An innovative method using vibrational theories to assess the periodontal attachment level of natural teeth is presented in this study.

METHODS

Modal testing technique, a non-destructive and time-saving method, was used for non-invasive and quantitative measurement of the natural frequencies of the upper central incisor in vivo and in vitro. A finite element model was established, and modal testing experiments were simulated to assess the relationship between bone level and teeth.

RESULTS

The first dominant natural frequency of healthy human upper central incisors ranges from 710 Hz to 3,360 Hz, with an average of 1,701+/-679 Hz. Both in vitro experiment and finite element simulation showed that lowering of the attachment level causes a significant decrease in the natural frequencies, and a strong relationship (r = -0.99, P <0.01) was observed between the frequency and the bone level height.

CONCLUSIONS

Our results suggested that natural frequency is an important parameter for assessing the periodontal condition and that the modal testing technique is a useful supplemental method for assessing the attachment conditions of the periodontium.

Synthesis and characterization of stereospecific 1-propargyl-2-(dimethoxymethyl)-1-cyclohexanols

Stereochemical isomers with hydroxy groups were synthesized by reacting 2-(dimethoxymethyl)cyclohexanone with propargylmagnesium bromide. The stereo chemical structures were identified by NMR spectral interpretation and the geometry optimization. To assist the NMR interpretation, geometry optimization based on semi-empirical AM1 and PM3 methods was applied. Throughout this study, the structures of the two isomers were all determined and 1H and 13C NMR spectra were fully assigned. It was proven that the less polar isomer is an axial alcohol and the more polar one is an equatorial alcohol.

Osseous metaplasia with functioning bone marrow in hydroxyapatite orbital implants

BACKGROUND

Bone formation within the hydroxyapatite implant has been reported in explanted spheres in humans. Bone-specific differentiation was observed to occur earlier in the pores of spherical hydroxyapatite implants enhanced with osteogenin within the rabbit socket. We observed previously unreported bone marrow formation in a coralline hydroxyapatite implant placed into the rabbit orbit after evisceration.

METHODS

One eye of each of 10 New Zealand white rabbits weighing between 2 and 3 kg was eviscerated and implanted with hydroxyapatite spheres. The explanted hydroxyapatite spheres 20 weeks after surgery were examined under the microscope.

RESULTS

Histopathologic examination of the excised implants showed the presence of trabeculae of mature bone with fatty marrow and hematopoietic elements. Scattered throughout the fatty tissue were bone marrow elements consisting of precursors of the granulocytic and erythroid series and also megakaryocytes.

CONCLUSION

The osseous metaplasia with functioning bone marrow was incidentally observed in the coralline hydroxyapatite implant without the addition of any osteogenesis-inducing agents.