Whole exome sequencing reveals compound heterozygous mutations in SLC19A3 causing biotin-thiamine responsive basal ganglia disease

Biotin-thiamine responsive basal ganglia disease (BTBGD) is a rare metabolic condition caused by mutations in the SLC19A3 gene. BTBGD presents with encephalopathy and significant disease progression when not treated with biotin and/or thiamine. We present a patient of Mexican and European ancestry diagnosed with BTBGD found to have compound heterozygous frameshift mutations, one novel. Our report adds to the genotype-phenotype correlation, highlighting the clinical importance of considering SLC19A3 gene defects as part of the differential diagnosis for Leigh syndrome.

Residual stresses of sputtering titanium thin films at various substrate temperatures

This work seeks to characterize the residual stresses of titanium thin films as they are affected by various substrate temperatures during the sputtering process. The titanium thin films are deposited on silicon wafers by a RF magnetron sputter while different substrate temperatures are considered. The residual stresses are measured by both X-ray diffraction and a substrate curvature method, and consistent results are obtained by both methods. The results show that the residual stress decreases as the substrate temperature increases, in which the stress changes from tensile to compressive when the substrate temperature increases from 25 to 50 degrees C. Furthermore, the elastic modulus and hardness of the titanium thin films are tested with a nanoindenter using a standard Berkovich probe. Correlations between the residual stresses and mechanical properties measured by nanoindentation are also discussed.

Isolation and structure of pro-methionine-enkephalin: Potential enkephalin precursor from porcine hypothalamus

A hexapeptide that we have named pro-methionine-enkephalin has been isolated from acid extracts of porcine hypothalami and found to have the amino acid sequence H-Tyr-Gly-Gly-Phe-Met(O)-Arg-OH. This peptide is not a fragment of either porcine beta-lipotropin or beta-endorphin, which suggests that it could be a precursor of [Met]enkephalin in the brain by a pathway differing from the one usually postulated. The existence of still larger precursors of [Met]enkephalin, perhaps related to the recently reported alpha-neo-endorphin, is strongly implied by these studies. Synthetic H-Tyr-Gly-Gly-Phe-Met-Arg-OH exhibited low, but significant, opiate activity in vitro.

p16/p14(ARF) cell cycle regulatory pathways in primary neuroblastoma: p16 expression is associated with advanced stage disease

p16 regulates the G(1)-S cell cycle transition by inhibiting the cyclin D-cyclin-dependent kinase (CDK)4/CDK6-mediated phosphorylation of retinoblastoma protein (pRb). We examined the possible derangement of the p16-CDK/cyclin D-pRb pathway in 40 primary neuroblastomas including 18 samples in the unfavorable stages (C and D) and 22 in the favorable stages (A, B, and Ds) by PCR, reverse transcription-PCR, Western blot, and immunohistochemistry and correlated the results with clinical outcome. No samples harbored alterations of the p16 gene. Interestingly, the samples in the unfavorable stages exhibited expression of p16 mRNA and protein more frequently than those in the favorable stages [mRNA, 9 of 18 (50%) versus 2 of 22 (9%), P = 0.006; protein, 5 of 16 (31%) versus 0 of 18 (0%), P = 0.013]. Alterations of the downstream components of the pathway were infrequent. pRb was deregulated in the majority of samples investigated [27 of 33 (82%), 24 with hyperphosphorylated pRb and 3 with no pRb protein]. The phosphorylation status of pRb did not correlate with p16 protein expression, suggesting that the elevated p16 protein may not be functioning properly to regulate the pathway. Among patients of all stages, p16 expression was significantly associated with a lower overall survival. There was no overexpression of MDM2, and loss of p14(ARF) expression and p53 mutation were infrequent events. Taken together, these findings suggest that up-regulated p16 expression may represent a unique feature of aggressive neuroblastoma.

In vitro cellular response of retinoic acid treated human oral cancer cell lines

BACKGROUND

The purpose of this study is to identify the cellular response ofretinoic acid-treated human oral cancer cell lines.

METHODS

Seven human oral cancer cell lines KB, SCC4, SCC9, SCC15, SCC25, OEC-M1, OC1 and OC2 were used for cell culture experiments. Direct cell number counting method was utilized to evaluate cellular response of these human oral cancer cells at the presence or absence of all-trans RA at 1 mM.

RESULTS

Through 7-day observation, the cell population of SCC9, SCC15 and SCC25 of RA-treated groups decreased when compared with the non RA-treated groups. These three cell lines were further verified using [3H] thymidine incorporation DNA synthesis assay. KB, SCC4, OC1, OC2 and OEC-M1 cell lines did not show growth inhibition at the presence of RA at 1 mM.

CONCLUSIONS

The molecular event of how SCC9, SCC15 and SCC25 are inhibited by RA and how KB, OC1, OC2 and OECM1 are resistant to RA can be further explored on the basis of this study.

Synthesis of fatty acid esters by recombinant Staphylococcus epidermidis lipases in aqueous environment

Various flavor esters were obtained by using recombinant lipases from Staphylococcus epidermidis as a catalyst in an aqueous environment. These esters were enzymatically synthesized to overcome the problems associated with chemical processes. This study showed that the S. epidermidis lipases could catalyze ester synthesis from decyl alcohol and fatty acids of different chain length. The wild-type and mutant lipases (M419A and V649I) could efficiently catalyze the synthesis of decyl alcohol esters of unsaturated fatty acids. In contrast, the yield of decyl laurate was better by wild-type and mutant enzyme V6491, but mutant enzyme M419A only favored the synthesis of decyl myristate. The esterification of oleic acid and various carbon-chain-length alcohols from ethanol to hexadecanol increased up to decanol by wild-type and M419A mutant enzymes and reached an optimum for dodecanol by V6491 mutant enzyme. The enzyme is potentially useful in food industries such as dairy product flavoring.

Effects of tumor necrosis factor alpha on taurine uptake in cultured rat astrocytes

Taurine is known to play a major role in volume regulation in astrocytic swelling associated with stroke and brain trauma. Apart from brain edema, the severity of brain injury is related to the levels of inflammatory cytokines such as tumor necrosis factor alpha (TNFalpha). TNFalpha had been shown to be closely associated with brain edema formation since the neutralization of TNFalpha reduced brain edema. Considering taurine has osmoregulatory functions in astrocytes, experiments were performed to study the effects of TNFalpha on taurine uptake in cultured astrocytes. Astrocytes exposed to 20 ng/ml of TNFalpha for 48 h showed a 91% increase in taurine uptake and significant increase was observed after 24 h exposure. This cytokine caused neither significant changes in cell volume nor taurine release. The increased in taurine uptake induced by TNFalpha was unlikely resulted from the modification of Na(+) movement because TNFalpha decreased tyrosine uptake, Na(+)-dependent transport system. In contrast to TNFalpha, interferon-gamma (IFNgamma) did not significantly affect taurine uptake. Taken together, our results did not support a suggestion that TNFalpha affects cell volume regulation via modulating taurine uptake in astrocytes. Increasing lines of evidence have demonstrated that taurine has anti-inflammatory and anti-oxidative effects, these findings therefore suggested that the increase in taurine uptake might be an adaptive response or a tool for astrocytes against oxidative stress.

Neurons reduce glial responses to lipopolysaccharide (LPS) and prevent injury of microglial cells from over-activation by LPS

The microenvironment of the CNS has been considered to tonically inhibit glial activities. It has been shown that glia become activated where neuronal death occurs in the aging brain. We have previously demonstrated that neurons tonically inhibit glial activities including their responses to the bacterial endotoxin lipopolysaccharide (LPS). It is not clear whether activation of glia, especially microglia in the aging brain, is the consequence of disinhibition due to neuronal death. This study was designed to determine if glia regain their responsiveness to LPS once the neurons have died in aged cultures. When cultured alone, glia from postnatal day one rat mesencephalons stimulated with LPS (0.1-1000 ng/mL) produced both nitric oxide (NO) and tumor necrosis factor alpha (TNFalpha), yielding a sigmoid and a bell-shaped curve, respectively. When neuron-containing cultures were prepared from embryonic day 14/15 mesencephalons, the shape of the dose-response curve for NO was monotonic and the bell-shaped curve for TNFalpha production was shifted to the right. After 1 month of culture under conditions where neurons die, the production curves for NO and TNFalpha in LPS-stimulated glia shifted back to the left compared to mixed neuron-glia cultures. Immunostaining of rat microglia for the marker CR3 (the receptor for complement component C3) demonstrated that high concentrations of LPS (1 microg/mL) reduced the number of microglia in mixed-glial cultures. In contrast, reduction of CR3 immunostaining was not observed in LPS-stimulated mixed neuron-glia cultures. Taken together, the results demonstrate that disinhibition of the glial response to LPS occurs after neurons die in aged cultures. Once neurons have died, the responsiveness of glia to LPS is restored. Neurons prevented injury to microglia by reducing their responsiveness to LPS. This study broadens our understanding of the ways in which the CNS microenvironment affects cerebral inflammation.

In vitro sensitivity of T-cell lymphoblastic leukemia to UCN-01 (7-hydroxystaurosporine) is dependent on p16 protein status: a Pediatric Oncology Group study

p16 regulates the cell cycle pathway by inhibiting the cyclin Ds-cyclin-dependent kinase (CDK) 4/6-mediated phosphorylation of retinoblastoma protein (pRb). Previously, we reported that most primary T-cell acute lymphoblastic leukemia (T-ALL) harbored p16 inactivation and hyperphosphorylated pRb without cyclin Ds or CDK4/6 alterations. Therefore, inhibiting CDK4/6 may be an ideal therapeutic approach for p16 (-) T-ALL. UCN-01 (7-hydroxystaurosporine) is a potent antitumor agent that exerts its effects through the inhibition of CDKs. We now report that p16 protein expression status of T-ALL cells influences their sensitivity to UCN-01. In 36 primary T-ALL cells, the IC50s of UCN-01 in the 27 p16 (-) cells (43+/-52 nM) was significantly lower than that in the 9 p16 (+) cells (258+/-260 nM). Our results suggest that agents like UCN-01 may be useful as a p16-selective therapy for T-ALL.

Measured and calculated effects of mutations in bacteriophage T4 lysozyme on interactions in solution

Understanding the molecular determinants of protein interactions in solution has fundamental implications for understanding protein solution thermodynamics and, hence, processes as diverse as separations performance and cellular self-organization. Our earlier theoretical calculations indicate that the protein-protein interactions are dominated by a small number of configurations in which highly complementary surface regions are apposed, rather than by the overall colloidal interactions. To examine this paradigm more explicitly, we investigated the effects of protein structural modifications on protein-protein interactions. Experimental measurements are presented of B(22)(') values of a set of mutants of Ser44 in bacteriophage T4 lysozyme. Effects are seen with both charged and uncharged substitutions. The results with the charged substitutions follow the expected trends, whereas those with the uncharged substitutions may be explained by the impact of the mutations on the local protein geometry, which directly affects the complementarity of protein interactions. These effects are also captured well by molecular calculations that account for the mutations. The interaction energetics between protein pairs could provide information on the propensity for adventitious interactions, which can have important implications for separations and for normal and pathological self-assembly. Thus, protein structural data implicit in genomic information, coupled with appropriate calculational and experimental tools, can ultimately provide insights into protein interactions in vivo and in bioprocessing.

Immune modulatory effects of neural cell adhesion molecules on lipopolysaccharide-induced nitric oxide production by cultured glia

Activation of glial cells often occurs at sites of neuronal injury or death and where there is disruption of communication between glia and neurons. We have previously reported that neurons exert an inhibitory influence on LPS-stimulated nitric oxide (NO) production in glial cells. We hypothesized that neural cell adhesion molecules (NCAM) might mediate this inhibitory effect, and this study was designed to elucidate the role of NCAM on lipopolysaccharide (LPS)-induced NO production. We found that soluble NCAMs reduced LPS-stimulated NO production by cultured glia. A monoclonal antibody that recognizes the third immunoglobulin (Ig) domain and can mimic the functions of NCAMs reduced LPS-stimulated NO production, whereas another antibody that binds to other regions of the NCAM did not modulate NO production. Using a 10-amino acid peptide from the third Ig domain of the NCAM, a peptide fragment within the region recognized by the NCAM antibody, mimics the effect of the molecule in reducing NO production. This study demonstrated that NCAMs could modulate LPS-stimulated NO production, most likely via interaction between NCAMs. These results suggest that neuron-glia interactions via NCAMs play an important role in regulating the activities of glial cells in the brain.

Image-plane cylindrical holographic stereogram

A two-step holographic process is introduced to fabricate a cylindrical multiplex hologram as an image-plane hologram. By adoption of the achromatic angle in the process the hologram is capable of generating an achromatic image. The most important factors, the location as well as the width of the viewing slits, that affect the quality of the observed image are analyzed and discussed. The change of aspect ratio for the observed image as a function of the viewing distance is theoretically and numerically analyzed. This method can not only eliminate the annoying picket-fence effect but can also increase the vertical viewing range for the observer. Computer simulations as well as experimental results are provided.

High concentrations of extracellular potassium enhance bacterial endotoxin lipopolysaccharide-induced neurotoxicity in glia-neuron mixed cultures

A sudden increase in extracellular potassium ions (K(+)) often occurs in cerebral ischemia and after brain trauma. This increase of extracellular K(+) constitutes the basis for spreading depression across the cerebral cortex, resulting in the expansion of neuronal death after ischemic and traumatic brain injuries. Besides spreading depression, it has become clear that cerebral inflammation also is a key factor contributing to secondary brain injury in acute neurological disorders. Experiments to validate the relationship between elevated levels of extracellular K(+) and inflammation have not been studied. This study aims to elucidate the roles of high concentrations of extracellular K(+) in bacterial endotoxin lipopolysaccharide-induced production of inflammatory factors. Increased concentration of KCl in the medium (20mM) significantly enhanced neurotoxicity by lipopolysaccharide in glia-neuron mixed cultures. To delineate the underlying mechanisms of increased neurotoxicity, the effects of high extracellular K(+) were examined by using mixed glial cultures. KCl at 20mM significantly enhanced nitrite, an index for nitric oxide, production by about twofold, and was pronounced from 24 to 48h, depending on the concentration of KCl. Besides nitric oxide production of tumor necrosis factor-alpha was also enhanced. The augmentative effects of high KCl on the production of inflammatory factors were probably due to the further activation of microglia, since high KCl also enhanced the production of tumor necrosis factor-alpha in microglia-enriched cultures. The increased production of nitrite by high K(+) was eliminated through use of a K(+)-blocker. Taken together, the results show that increases of extracellular K(+) concentrations in spreading depression augment lipopolysaccharide-elicited neurotoxicity, because production of inflammatory factors such as nitric oxide and tumor necrosis factor-alpha are potentiated. Since spreading depression and cerebral inflammation are important in acute neurological disorders, the present results suggest a biochemical mechanism: elevated extracellular K(+) concentrations augment glial inflammatory responses, and thus the neurotoxicity.

Reduction by naloxone of lipopolysaccharide-induced neurotoxicity in mouse cortical neuron-glia co-cultures

An inflammatory response in the CNS mediated by activation of microglia is a key event in the early stages of the development of neurodegenerative diseases. Using mouse cortical mixed glia cultures, we have previously demonstrated that the bacterial endotoxin lipopolysaccharide induces the activation of microglia and the production of proinflammatory factors. Naloxone, an opioid receptor antagonist, inhibits the lipopolysaccharide-induced activation of microglia and the production of proinflammatory factors. Using neuron-glia co-cultures, we extended our study to determine if naloxone has a neuroprotective effect against lipopolysaccharide-induced neuronal damage and analysed the underlying mechanism of action for its potential neuroprotective effect. Pretreatment of cultures with naloxone (1 microM) followed by treatment with lipopolysaccharide significantly inhibited the lipopolysaccharide-induced production of nitric oxide and the release of tumor necrosis factor-alpha, and significantly reduced the lipopolysaccharide-induced damage to neurons. More importantly, both naloxone and its opioid-receptor ineffective enantiomer (+)-naloxone were equally effective in inhibiting the lipopolysaccharide-induced generation of proinflammatory factors and the activation of microglia, as well as in the protection of neurons. These results indicate that the neuroprotective effect of naloxone is mediated by its inhibition of microglial activity and may be unrelated to its binding to the classical opioid receptors.

Contribution of anion transporters to the acidosis-induced swelling and intracellular acidification of glial cells

This study examines the contribution of anion transporters to the swelling and intracellular acidification of glial cells from an extracellular lactacidosis, a condition well-known to accompany cerebral ischemia and traumatic brain injury. Suspended C6 glioma cells were exposed to lactacidosis in physiological or anion-depleted media, and different anion transport inhibitors were applied. Changes in cell volume and intracellular pH (pH(i)) were simultaneously quantified by flow cytometry. Extracellular lactacidosis (pH 6.2) led to an increase in cell volume to 125.1 +/- 2.5% of baseline within 60 min, whereas the pH(i) dropped from the physiological value of 7.13 +/- 0.05 to 6.32 +/- 0.03. Suspension in Cl(-)-free or HCO(3)(-)/CO(2)-free media or application of anion transport inhibitors [0.1 mM bumetanide or 0.5 mM 4, 4'-diisothio-cyanatostilbene-2,2'-disulfonic acid (DIDS)] did not affect cell volume during baseline conditions but significantly reduced cell swelling from lactacidosis. In addition, the Cl(-)-free or HCO(3)(-)/CO(2)-free media and DIDS attenuated intracellular acidosis on extracellular acidification. From these findings it is concluded that besides the known activation of the Na(+)/H(+) exchanger, activation of the Na(+)-independent Cl(-)/HCO(3)(-) exchanger and the Na(+)-K(+)-Cl(-) cotransporter contributes to acidosis-induced glial swelling and the intracellular acidification. Inhibition of these processes may be of interest for future strategies in the treatment of cytotoxic brain edema from cerebral ischemia or traumatic brain injury.

Post-transcriptional inhibition of lipopolysaccharide-induced expression of inducible nitric oxide synthase by Gö6976 in murine microglia

Glia in the brain respond to various toxins with an increased expression of inducible nitric oxide synthase (iNOS) and an increased production of nitric oxide (NO). Here, we report that lipopolysaccharide (LPS)-induced expression of iNOS was down-regulated post-transcriptionally through the destabilization of iNOS mRNA by the indolocarbazole compound, Gö6976, in murine microglia. This Gö6976 effect is specific for iNOS since tumor necrosis factor alpha was unaffected by the compound. Interestingly, the post-transcriptional effects ascribed to Gö6976 were not observed with other inhibitors of protein kinase A, C (PKC), G, or protein tyrosine kinases. Instead, these kinases appear to affect the iNOS/NO system at the transcriptional level. In the past, Gö6976 has been reported to be a rather specific inhibitor of PKC in vitro. Results from our experiments, through prolonged treatment with phorbol esters and with the various PKC inhibitors including phorbol ester-insensitive PKC isotype inhibitor, suggest that the Gö6976-mediated post-transcriptional regulation of iNOS gene expression and NO production in microglia is not mediated through its reputed effects on PKC activity. Since the effects of various neurotoxins and certain neurodegenerative diseases may be manifested through alterations in the iNOS/NO system, post-transcriptional control of this system may represent a novel strategy for therapeutic intervention.

Universal inactivation of both p16 and p15 but not downstream components is an essential event in the pathogenesis of T-cell acute lymphoblastic leukemia

p16/p15 regulate the cell cycle pathway by inhibiting the cyclin Ds-CDK4/6 mediated phosphorylation of pRb. We reported previously that in T-cell acute lymphoblastic leukemia (T-ALL), p16 and p15 were frequently (approximately 70%) inactivated at the DNA level by deletion, mutation, or hypermethylation. Therefore, we hypothesize that inactivation of the cell cycle regulatory pathway may be essential in the pathogenesis of T-ALL, and that the remaining T-ALL with a wild-type p16/p15 gene likely harbor inactivation of these genes at RNA or protein levels. Alternatively, the downstream components of the pathway including CDK4/6, cyclin Ds, and pRb may be deregulated. In 124 primary T-ALLs, we found inactivation of the p16 and p15 genes at the DNA level in 79 (64%) and 64 (52%) samples, respectively. Only 9 of the 45 samples with wild-type p16 expressed p16 protein, whereas the remaining 36 lacked p16 expression at the RNA or protein level. In the 60 samples with an intact p15 gene, only 2 expressed p15 mRNA, and the only one analyzed lacked p15 protein. Overall, the abrogation rates for p16 and p15 at DNA/RNA/protein levels were 93% (115 of 124) and 99% (123 of 124), respectively. Although no alterations were evident in cyclin Ds or CDK4/6, pRb was hyperphosphorylated in the majority of samples investigated. These findings strongly support that both p16 and p15 are specific targets in the deregulation of the cell cycle pathway in T-ALL and that the inactivation of these genes is most likely essential in the pathogenesis of this disease.

Biomechanical and histological studies of particulate hydroxylapatite implanted in femur bone defects of adult dogs

The purpose of this study was to investigate the biomechanical behavior and the histology of particulate hydroxylapatite (HA) implanted in bone defects created in femurs of 48 adult mongrel dogs. The bone defects, measuring 10 x 10 x 25 mm with or without HA implantation, were allowed to heal until the end of the 1st, 2nd, 3rd, 6th, 9th and 12th months after surgery. The harvested tissue specimens from the implant sites were processed into long cubic or rectangular prismatic forms. Their mechanical strengths were assessed using compression and shearing tests to measure the maximal compressive and shear stress by force loading on the middle portions of the specimens. Histological sections of each stage were processed with both decalcified and nondecalcified methods. The results showed that the mechanical strength of the tested specimens was closely related to the tissue regeneration within the bone defect. Progressive regeneration of new bone was observed at each stage, with complete bone formation at the 9-month period. A consistent increase in both maximal compressive stress and maximal shear stress was noted at each stage, responsive to the ossification and maturation of the regenerating tissue within the bone defect. This animal model provides a novel approach to directly estimate the tissue strength of the HA-implanted bone defect.

A novel effect of an opioid receptor antagonist, naloxone, on the production of reactive oxygen species by microglia: a study by electron paramagnetic resonance spectroscopy

Microglia as the first line of defensive cells in the brain produce free radicals including superoxide and nitric oxide (NO), contributing to neurodegeneration. An opioid receptor antagonist, naloxone, has been considered pharmacologically beneficial to endotoxin shock, experimental cerebral ischemia, and spinal cord injury. However, the mechanisms underlying these beneficial effects of naloxone are still not clear. This study explores the effects of naloxone on the production of superoxide and NO by the murine microglial cell line, BV2, stimulated with lipopolysaccharide (LPS) as measured by electron paramagnetic resonance (EPR). The production of superoxide triggered by phobol-12-myristate-13-acetate (PMA) resulted in superoxide dismutase (SOD)-inhibitable, catalase-uninhibitable 5,5-dimethyl-1-pyrroline N-oxide (DMPO) hydroxyl radical adduct formation. LPS enhanced the production of superoxide and triggered the formation of non-heme iron-nitrosyl complex. Cells pre-treated with naloxone showed significant reduction of superoxide production by 35%. However, it could not significantly reduce the formation of non-heme iron-nitrosyl complex and nitrite. Taken together, the results expand our understanding of the neuroprotective effects of naloxone as it decreases superoxide production by microglia.

Influence of neurons on lipopolysaccharide-stimulated production of nitric oxide and tumor necrosis factor-alpha by cultured glia

Cerebral inflammation often originates in a region where neuronal death occurs and thereafter slowly spreads outward. This study aimed to elucidate the roles of neurons in modulating the production of inflammatory factors stimulated by the bacterial endotoxin lipopolysaccharide (LPS). Culturing neurons with mixed glia reduced nitrite and tumor necrosis factor-alpha (TNF-alpha) production compared to cultures with only mixed glia, and shifted the dose-response curve to the right. The decreased nitrite and TNF-alpha production were not due to the cytotoxicity of LPS. Immunocytochemical analysis of glia-neuron co-cultures revealed the morphological changes in the activated microglia. Culturing PC12 cells with rat mixed-glia also reduced nitrite production. The influence of neurons on glial inflammation was partly due to the cell-cell contacts between neurons and glia via neural cell adhesion molecules (NCAM) because NCAM significantly reduced LPS-stimulated nitrite production. These results demonstrate that neurons reduce the production of inflammatory factors by glia. Since cerebral inflammation is important in many neurological disorders, this study might provide insight about the role of glia-neuron interactions in inflammatory responses in the brain.

Coronal approach for the replacement of the condylar head in bilateral temporomandibular joint ankylosis: report of three cases

Limitation of mouth opening has long been the chief complaint for patients who suffer from temporomandibular joint (TMJ) ankylosis. For surgical treatment of this disease, several ways have been employed for access to the condylar fossa, including the preauricular, postauricular, perimeatal, endaural and Risdon approaches. In this article, we report three patients with bilateral TMJ ankylosis who underwent replacement of both condylar heads using the bicoronal approach. The advantages demonstrated with this surgical technique are ease of access to the condylar head, ideal surgical exposure field, utility of temporalis muscle and fascia and minimal risk of facial paralysis.

Long-term increase of Sp-1 transcription factors in the hippocampus after kainic acid treatment

Systemic administration of kainic acid (KA), a glutamate receptor agonist, causes robust seizures and has been used as an excellent rodent model for human temporal lobe epilepsy. Recently, we have demonstrated that a single injection of KA increases the steady-state levels of proenkephalin (PENK) mRNA in the rat hippocampus for at least one year. However, the molecular mechanisms underlying this long-term increase in PENK mRNA levels have not been clearly defined. To determine the possible involvement of the Sp-1 transcription factors in this regulation, electrophoresis mobility-shift assays were used to study the expression of Sp-1 factors in the hippocampus after KA treatment. The results showed that there are long-lasting increases in Sp-1 DNA-binding activity. The Sp-1 DNA-binding complexes were only competed by the non-radioactive Sp-1 element and not by ENKCRE2, AP-1 or CRE elements, indicating the specificity of Sp-1 DNA-binding activity. Since the expression of Sp-1 parallels the time course of long-lasting increase in the expression of PENK mRNA and mossy fiber sprouting after KA treatment, we hypothesize that the increase in Sp-1 activity may be associated with the long-term changes in the plasticity of hippocampal function after KA-induced seizures.

Disk-type multiplex holography

A theory for making a disk-type multiplex hologram is derived. This theory relates the final image point, as seen by the observer, to a point on the original three-dimensional object through a set of equations. From these equations the distortion of the image and the wavelength as seen by each individual eye can be evaluated. Computer simulation shows the characteristics of this hologram. Some experimental results also confirm these characteristics. By reversing the process and specifying a desired image, we generated a set of distorted two-dimensional originals. The hologram fabricated with these distorted images can generate nearly distortion-free images.

Using three-dimensional-computerized tomography as a diagnostic tool for temporo-mandibular joint ankylosis: a case report

Roentgenographic examination has long been a useful diagnostic tool for temporo-mandibular joint (TMJ) disease. The methods include TMJ tomography, panoramic radiography and computerized tomography (CT) scan with or without injection of contrast media. Recently, three-dimensional CT (3D-CT), reconstructed from the two-dimensional image of a CT scan to simulate the soft tissue or bony structure of the real target, was proposed. In this report, a case of TMJ ankylosis due to traumatic injury is presented. 3D-CT was employed as one of the presurgical roentgenographic diagnostic tools. The conventional radiographic examination including panoramic radiography and tomography showed lesions in both sides of the mandible. CT scanning further suggested that the right-sided lesion was more severe than that on the left. With 3D-CT image reconstruction the size and extent of the lesions were clearly observable. The decision was made to proceed with an initial surgical approach on the right side. With condylectomy and condylar replacement using an autogenous costochondral graft on the right side, the range of mouth opening improved significantly. In this case report, 3D-CT demonstrates its advantages as a tool for the correct and precise diagnosis of TMJ ankylosis.

Technical note: a new model for quantitative analysis of brain oedema resolution into the ventricles and the subarachnoid space

OBJECTIVE

The aim of the current study was to develop an experimental animal model for quantitative analysis of oedema resolution via the subarachnoid space and the ventricular system using fluorescent oedema markers.

METHODS

Artificial cerebrospinal fluid (CSF) containing TRITC-albumin (MW 67.000D) and Na(+)-fluorescein (MW 376D) was continuously infused into the white matter of the left frontal lobe of New Zealand white rabbits (n = 6) at a rate of 100 microliters/h for 3 hrs. A closed cranial window for superfusion of the brain surface with artificial CSF fluid (3 ml/h) was implanted above the left parietal cortex for measurement of the fluorescence markers in the subarachnoid space. Uptake of the fluorescence indicators into the ventricles was quantified by ventriculo-cisternal perfusion (3 ml/h). The effluates were collected at 30 min intervals for 3 hrs after the start of infusion. Clearance of the oedema fluid into the perfusates was measured by fluorescence spectrophotometry.

RESULTS

At an intracranial pressure of 15.0 +/- 1.7 mm Hg (mean +/- SEM) both indicators started to accumulate in the subarachnoid and ventricular perfusates at 90 min following onset of oedema fluid infusion. The concentrations of the indicators in the ventricular system increased to 7.7 +/- 5.1% of Na(+)-fluorescein and 16.1 +/- 13.0% of TRITC-albumin of the total amount infused were recovered in the ventricular system at 3 hours after start of the oedema infusion, while 3.4 +/- 3.2% of Na(+)-fluorescein and 3.7% +/- 3.2 of TRITC-albumin, respectively, were found in the effluates of the subarachnoid space.

CONCLUSION

The present study demonstrates that resolution of vasogenic brain oedema into the cerebral ventricular system and the subarachnoid space following its entry into cerebral white matter can be quantitatively analysed using fluorescence markers, which serve as oedema fluid indicators. The results indicate that the oedema fluid is cleared not only into the ventricular system but also via the subarachnoid space.

Relevance of calcium homeostasis in glial cell swelling from acidosis

Tissue acidosis from trauma or ischemia induces cytotoxic brain edema, mainly affecting astrocytes. In vitro, lactacidosis induces a dose-dependent swelling of glial cells. Activation of membrane transporters and channels, also involved in regulation of intracellular pH (pHi), has been identified as underlying mechanism, although details are poorly understood. We have currently studied whether Ca(2+)-ions play a role in acidosis-induced glial swelling and the associated intracellular acidification. The medium pH of a cell suspension (C6 glioma) was lowered from control (7.4) to 6.2 by lactic acid. Cell volume (CV) and pHi were assessed by flow cytometry. During acidosis in normal medium (2.2 mM Ca2+) CV reached a maximum of 125.1%. In a calcium-free medium swelling from acidosis was inhibited by 74%, while additional buffering of intracellular calcium (Ca2+i) by BAPTA-AM had no further effect. Buffering of Ca2+i alone did not affect the CV increase from acidosis at all. pHi which is decreasing during acidosis was not influenced by the above modifications. The present experiments indicate that lactacidosis-induced glial swelling depends on the presence of extracellular Ca(2+)-ions, while alterations of Ca2+i do not seem to be involved.

Role of calcium ions in acidosis-induced glial swelling

Tissue acidosis occurring in cerebral ischemia and traumatic brain injury is a mediator of cytotoxic brain edema. In vitro, extracellular lactacidosis induces swelling of glial cells in a dose dependent manner. pH-regulatory membrane transporters and channels have been identified which are involved in the increase of the glial cell volume. Underlying mechanisms of their activation are poorly understood, however. We have, therefore, addressed the question, whether and how Ca(2+)-ions play a role in acidosis-induced glial swelling and intracellular acidification. For that purpose C6 glioma cells were suspended and the pH in the medium was lowered from 7.4 (baseline) to 6.2 by isotonic lactic acid. Cell volume and intracellular pH (pHi) were assessed by flow cytometry. In the presence of Ca(2+)-ions the cell volume reached a maximum of 125.1% from acidosis. In experiments using a calcium-free suspension medium, cell swelling from acidosis was inhibited by 74%. Additional buffering of intracellular calcium (Ca2+i) had no further inhibitory effect on acidosis-induced cell swelling, while buffering of Ca2+i by BAPTA-AM alone did not affect the glial volume increase secondary to administration of lactic acid. pHi which was decreasing from acidosis was not affected by the experimental modifications of the Ca(2+)-concentration in the medium or cytosol. The present data indicate that lactacidosis-induced glial swelling depends on the presence of extracellular Ca(2+)-ions, while release of Ca(2+)-ions from intracellular stores does not seem to be involved.

Quantitative analysis of brain edema resolution into the cerebral ventricles and subarachnoid space

Resolution of vasogenic brain edema was examined using a model of infusion of fluid into the brain of rabbits. For this purpose infusion of Texas Red-albumin (MW 67.000 D) and sodium fluorescein (MW 376 D) dissolved in artificial cerebrospinal fluid (mock CSF) was made into the white matter of the left frontal lobe of the brain. In order to quantify the portion of edema fluid which was cleared by the ventricular system, a ventriculo-cisternal perfusion was performed with mock CSF. A closed cranial window was implanted above the left parietal brain for superfusion of the cerebral cortex with mock CSF, in order to study resolution of the artificial edema fluid via the subarachnoid space. CSF-samples were collected in 30 minutes-intervals and analysed with a spectrophotometer. The clearance of edema fluid was examined under low (2-5 mmHg) and medium (9-12 mmHg) intracranial pressure (ICP). In the low-pressure group both edema fluid markers were found in the ventriculo-cisternal and subarachnoid perfusate at 60 min and 90 min, respectively, after start of infusion. In the group with moderately increased ICP the markers appeared at 90 min and 120 min, respectively. The amount of clearance of fluorescent dye via the subarachnoid space was the same in both groups and independent of the intracranial pressure.

Effect of alpha-trinositol on swelling and damage of glial cells by lactacidosis and glutamate

The therapeutic efficacy of alpha-trinositol (D-myo-inositol-1,2,6-trisphosphate), an isomer of the intracellular messenger IP3, was analyzed for cytotoxic swelling and damage of glial cells in vitro from lactacidosis or glutamate. Lactacidosis and the interstitial accumulation of glutamate are prominent sequelae in ischemic or traumatic brain tissue. C6 glioma cells harvested from culture and suspended in a physiological medium were either exposed to pH 5.0 by administration of lactic acid, or to 1 mM glutamate at normal pH. Cell swelling and viability were quantified by blood flow cytometry. Addition of alpha-trinositol (3 mM) under control conditions at pH 7.4 resulted in transient cell shrinking to 96.5 +/- 1.3% of control within 3 min (p < 0.05). Lactacidosis of pH 5.0 led to an increase in cell volume to 139.7 +/- 1.3% within 20 min, whereas alpha-trinositol reduced the swelling response by approximately 25% (p < 0.01). In addition, cell viability was severely affected at pH 5.0 amounting to only 53.8 +/- 3.1% after 60 min. alpha-Trinositol was found to markedly improve cell viability; at 60 min 70.2 +/- 1.6% of the cells were still viable (p < 0.01). Addition of glutamate (1 mM) led to a steady increase in cell size, reaching 110% of control after 120 min, irrespective of wether alpha-trinositol was present or not. The attenuation of cell swelling may be attributed to an interference with pH-regulatory mechanisms, such as the Na+/H(+)-antiporter, while protection of cell viability might be caused be effects of alpha-trinositol on Ca(2+)-overload. On the other hand, the increase in cell volume by glutamate associated with its intracellular uptake was not influenced by alpha-trinositol.

Effect of mild and moderate hypothermia on the acidosis-induced swelling of glial cells

The effect of mild (32 degrees C) and moderate (27 degrees C) hypothermia was analyzed on the cell volume and intracellular pH (pHi) of C6 glioma cells at normal pH and during lactacidosis at pH 6.2 in vitro. The cells were suspended in an incubation chamber under continuous control of pH, PO2 and temperature. Cell swelling was quantified by an advanced Coulter-system. pHi was measured by flow cytometry using the fluorescent dye bis-carboxyethyl carboxyfluorescein (BCECF). Following a control period at 37 degrees C, the ambient temperature was decreased to 32 degrees C for 30 min, and subsequently to 27 degrees C for another 30 min. Hypothermia alone led to an immediate and significant cell volume increase of 107.3 +/- 0.4% (mean +/- SEM) of control after 30 min at 32 degrees C, and further swelling to 110.5 +/- 0.9% after 30 min at 27 degrees C. Yet, hypothermia (27 degrees C) afforded partial protection against the acidosis-induced cell swelling at pH 6.2, which was reaching to 120.4 +/- 0.9% in the normothermic control group after 60 min, while only to 111.3 +/- 0.9% at 27 degrees C. Hypothermia, however, was associated with a more pronounced decrease of the pHi during acidosis (6.3 +/- 0.04) as compared to that of the normothermic control falling then to 6.5 +/- 0.03. The results demonstrate that mild and moderate hypothermia induce glial cell swelling, but simultaneously inhibit cell swelling from acidosis. The protection against cell swelling, however, has its price as indicated by the enhancement of the intracellular acidification.

Role of protein kinase C in acidosis induced glial swelling--current understanding

A major factor in secondary brain injury following cerebral trauma is accumulation of lactic acid resulting in glial swelling. Further, evidence obtained in this context demonstrates activation of protein kinase C (PKC) under these circumstances. Glial swelling from acidosis is attributable to activation of the Na+/H(+)-exchanger, mediating influx of Na(+)-ions in exchange for the extrusion of H+ ions. The antiporter is activated following phosphorylation by PKC. The current study was made to elucidate the role of PKC activation in acidosis-induced glial swelling. For that purpose, suspended C6 glioma cells were used to examine changes of the cell volume and intracellular pH (pHi). Acidosis was induced by administration of isotonic lactic acid. Stimulation of PKC by the phorbol-ester PMA was significantly enhancing glial swelling from severe acidosis (pH 6.2), whereas the decrease of pHi was somewhat attenuated. On the other side, inhibition of PKC by staurosporine did not affect cell swelling nor the decrease of pHi from acidosis. The results indicate that activation of PKC in cerebral trauma or ischemia may enhance glial swelling from lactacidosis.

Swelling and damage of glial cells by lactacidosis and glutamate: effect of alpha-trinositol

The therapeutical efficacy of alpha-trinositol (D-myo-inositol-1,2,6-trisphosphate), an isomer of the intracellular messenger IP3, was analyzed on cytotoxic swelling and damage of glial cells in vitro from lactacidosis or glutamate. C6 glioma cells suspended in a physiological medium were either exposed to pH 5.0 by administration of lactic acid, or to 1 mM glutamate. Cell swelling and viability were quantified by flow cytometry. Lactacidosis of pH 5.0 led to an increase in cell volume to 139.7 +/- 1.3% within 20 min whereas alpha-trinositol was reducing the swelling response by approximately 25% (P < 0.01). In addition, at pH 5.0 the fraction of viable cells was lowered from 94.3 +/- 0.2% (control) to only 53.8 +/- 3.1% after 60 min. Alpha-trinositol was found to protect also cell viability; at 60 min of lactacidosis 70.2 +/- 1.6% of the cells still were viable (P < 0.01). The addition of glutamate (1 mM) to the cell suspension led to a steady increase in cell size, reaching 110% of control at 120 min, irrespectively of whether alpha-trinositol was added or not.

Sebaceous carcinoma of buccal mucosa. Report of a case

A case of sebaceous carcinoma arising in the buccal mucosa is described.

Studying the active site pocket of Staphylococcus hyicus lipase by site-directed mutagenesis

Site-directed mutagenesis of a previously constructed, recombinant Staphylococcus hyicus lipase (49 kDa) showed that Val363 played a role in catalysis and substrate-binding. In comparison with wild type enzyme, the 64% and 89% decrease in the catalytic efficiency (kcat/Km) of the V363N and V363A enzymes, respectively, were largely caused by a 3.5- and 5.5-fold increase in the substrate-binding affinity (Km), respectively. In comparison with wild type enzyme, a G371A enzyme showed a 40% decrease in the Km, suggesting that G371 was important for substrate-binding specificity. Site-directed mutagenesis of the active site Asp559 revealed that in comparison with wild type enzyme, a D559E enzyme exhibited a 47% decrease in the kcat/Km but a twofold increase in the Km for p-nitrophenyl butyrate, suggesting that Asp-559, a component of the catalytic triad, was involved in substrate-specificity.

Facile purification of highly active recombinant Staphylococcus hyicus lipase fragment and characterization of a putative lid region

A fragment of Staphylococcus hyicus lipase gene (Ala248 to Ala640) was inserted into plasmid pET20(b+). The resulting His-tagged recombinant protein (49 kDa) was overexpressed in Escherichia coli BL21(DE3) as an highly active lipase and was purified by nickel-coupled resin. Site-directed mutagenesis showed that in comparison with wild type enzyme, the L326F and L326A enzymes showed a 3.4 and 5 fold increase in the K(m), respectively, but only a 44% and a 64% decrease in the kcat/K(m), respectively, suggesting that Leu326 of the putative lid participated in substrate-binding.

Characterization of the ferrous ion binding sites of apple 1-aminocyclopropane-1-carboxylate oxidase by site-directed mutagenesis

The putative ferrous ion binding sites (H177, D179, and H234) of apple fruit 1-aminocyclopropane-1-carboxylate oxidase determined by homology comparisons with enzymes which required non-haem Fe2+ for activity were altered by site-directed mutagenesis. The activities of mutants (H177F, D179H, D179A, H234F, and H234D) were completely lost. SDS-PAGE and western immunoanalysis confirmed that loss of enzyme activity in mutants was not due to impaired enzyme expression. These results strongly suggest that H177, D179, and H234 are the Fe2+ binding site.

Premedication with diclofenac and prednisolone to prevent postoperative pain and swelling after third molar removal

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) and steroid are able to effectively reduce the postoperative sequelae after impacted third molar removal. However, few studies have evaluated the activity of the combined effects of these two drugs. The purpose of this study was to evaluate whether a single dose of prednisolone, taken orally before operation, would increase the effects of diclofenac in preventing pain and swelling after surgical removal of impacted third molars.

METHODS

Thirty healthy patients requiring surgical removal of four third molars were randomly assigned to two groups. In group A, patients were preoperatively given 50 mg of either diclofenac or placebo when impacted teeth were removed on each side. In group B, in addition to 50 mg of diclofenac, 10 mg of prednisolone or placebo was administered. Postoperative pain, swelling and range of mouth opening were recorded.

RESULTS

Preoperative administration of 50 mg of diclofenac could relieve pain and swelling more than the placebo. Additional 10 mg of prednisolone could further reduce swelling.

CONCLUSIONS

The combination of diclofenac and prednisolone has a better analgesic and anti-inflammatory effect.

Site-directed mutagenesis of a novel serine arylesterase from Vibrio mimicus identifies residues essential for catalysis

Site-directed mutagenesis (SDM) of an arylesterase (the arylesterase) from Vibrio mimicus revealed that residues S29, H153, and D96 constituted a catalytic triad. The use of a serine residue for ester hydrolysis by the arylesterase proves that the enzyme is a novel serine arylesterase. SDM also showed that D28 was necessary for the esterase activity; to our knowledge it is the first time that a residue immediately preceding the active-site serine in esterases was shown biochemically to possess such a property. The results further suggest that D28 plays a role in substrate-binding. Residue 31 was firmly shown to participate in the binding of N-acetyl-D, L-phenylalanine beta-naphthyl ester (NAPNE), an artificial substrate for chymotrypsin. The S31G enzyme showed a 4 fold decrease in the Km for NAPNE over that of wild type enzyme, proving residue 31 is important for substrate-specificity. A mechanism for binding and catalysis of esters by the arylesterase is proposed, which includes the unique role of S31 for aromatic (hydrophobic) acyl-binding. The biochemical properties of the arylesterase suggest that the enzyme stands out as a member of a distinct subfamily within a recently proposed, lipolytic enzyme family.

Swelling, intracellular acidosis, and damage of glial cells

Cerebral ischemia and severe head injury among others are associated with a limited availability of oxygen, leading to cell catabolism as well as anaerobic glycolysis. Resulting metabolites, such as arachidonic- and lactic acid, can be expected to leak into perifocal brain areas, contributing there to cytotoxic swelling and damage of neurons and glia. Since elucidation of mechanisms underlying cell swelling and damage in the brain is difficult in vivo, respective investigations were carried out in vitro using suspended glial cells. Thereby, effects of arachidonic acid (AA) and of lactacidosis on glial cell volume, intracellular pH (pHi), and cell damage were analyzed utilizing flow cytometry. AA led to an immediate, dose dependent swelling and intracellular acidosis of glial cells. A concentration of 0.1 mM increased cell volume to 110% of control and decreased pHi to 7.05. Whereas glial swelling was permanent, pHi recovered to baseline after 90 min. Cell viability of 90% remained unchanged after addition of AA up to 0.1 mM, while at 0.5 mM it was significantly decreasing. Glial swelling from AA was nearly completely inhibited by the aminosteroid U-74389F or by using a Na(+)-free suspension medium for the experiment. Acidification of the medium to pH 6.8 or 6.2 led to a cell volume of 110% or 120% of control without affecting cell viability. The cells were not capable to defend their normal pHi during lactacidosis of the suspension medium but became acidotic as well. Addition of amiloride or utilization of Na(+)-free medium inhibited cell swelling from lactacidosis, while intracellular acidosis was even more pronounced. The results indicate that AA as well as acidosis are potent mediators of glial swelling and damage at levels found under pathophysiological conditions in the brain in vivo. Whereas intracellular acidification caused by AA was reversible, glial cells were unable to regulate their pHi during maintenance of extracellular acidosis. Concerning the mechanisms of glial swelling by AA, the production of oxygen- and lipid radicals might play a major role in the swelling process. The results indicate a role of the Na+/H(+)-antiporter in acidosis-induced glial swelling, whereas the exchanger has a limited significance for maintenance of pHi. As seen, the final pathway of glial swelling from both, AA and lactacidosis, requires a net influx of Na(+)-ions, probably together with Cl-ions, and osmotically obliged water.

Vibrio mimicus arylesterase has thioesterase and chymotrypsin-like activity

A Vibrio mimicus serine arylesterase and an Escherichia coli thioesterase/serine protease share 49.4% amino acid identity. The arylesterase has thioesterase activity for benzoyl-CoA and chymotrypsin-like activity for N-carbobenzoxy-L-phenylalanine p-nitrophenyl ester (NBPNPE). The gene encoding the V. mimicus enzyme is designated etpA. Substituting Ser31 of the V. mimicus enzyme with a glycine or an alanine altered its activity. In comparison with wild type enzyme, the S31A enzyme showed a 5-fold increase and 57% decrease in the catalytic efficiency for benzoyl-CoA and NBPNPE, respectively, and the S31G enzyme showed a 3.6-fold increase and 43% decrease in the catalytic efficiency for benzoyl-CoA and NBPNPE, respectively. For the two mutant enzymes an 8-fold decrease and a 6- to 7-fold increase in Km were seen for benzoyl-CoA and NBPNPE, respectively. The mutagenesis results prove that residue 31 plays an important role in the substrate-specificity.

Reductions in tissue plasminogen activator and thrombomodulin in blood draining veins damaged by venous access devices

A frequent complication of venous access devices (VADs) is axillary-subclavian venous thrombosis. To study this problem we have compared blood drawn through VADs with peripheral blood samples in a group of oncology patients with venographically demonstrated venous damage (N = 14) and a group with normal venograms (N = 21). The samples were assayed for a battery of proteins believed to be involved in thrombogenesis. After approximately six weeks of catheterization the venographically abnormal patients had significantly less thrombomodulin (P = 0.0055) and significantly higher PAI:tPA (P = 0.022) in catheter-drawn samples as compared with the venographically normal group. Although the data are inconclusive, it is hypothesized that these changes resulted from local endothelial injury.

Maxillary odontogenic carcinoma with distant metastasis to axillary skin, brain, and lung: case report

We present a case of odontogenic carcinoma with ghost-cell keratinization of the right maxilla, with a history of 23 years after initial treatment. Within this period, multiple local recurrence, as well as metastasis to axilla, brain, and lung, was noted. Several attempts at resection of the primary lesion were unsuccessful at achieving local control, even when supplemented with chemotherapy and radiotherapy. Metastatic tumors were studied histologically, and their morphology coincided with that of the primary tumor. The medical history of the patient and pathologic findings of the tumor are reviewed.

Venographic surveillance of tunneled venous access devices in adult oncology patients

BACKGROUND

Tunneled venous access devices (VADs) are often essential in the care of patients with advanced malignancies, but they carry an uncertain risk of thrombosis.

METHODS

To determine the incidence of venoocclusion related to silicone VADs in a population of adult oncology patients, we prospectively studied 50 individuals with upper extremity venograms approximately 6 weeks after their VADs had been implanted. Twenty-one of these patients were reevaluated with venograms approximately 12 weeks after catheterization. In addition, venograms were performed on a separate group of 24 patients who needed catheterization of axillary-subclavian veins that had been catheterized in the past.

RESULTS

The 6-week venograms in the prospective study showed partial venous obstruction in 15 patients (30%), whereas three (6%) had developed symptomatic total venoocclusion by this time. The 12-week venograms showed two additional complete occlusions. Venograms of 30 previously catheterized veins showed complete venoocclusion in nine (30%), although only two had a history of thrombosis.

CONCLUSIONS

Our observations indicate that VADs frequently cause partial venoocclusion within the first 6 weeks of catheterization and that permanent venous damage from VADs is common, even without a history of VAD-related thrombosis.

Upper extremity impedance plethysmography in patients with venous access devices

Central venous access devices (VADs) are often associated with thrombotic obstruction of the axillary-subclavian venous system. To explore the accuracy of impedance plethysmography (IPG) in identifying this complication we performed IPG on 35 adult cancer patients before their VADs were placed and approximately 6 weeks later. At the time of the second IPG the patients also underwent contrast venography of the axillary-subclavian system. The venograms revealed partial venous obstruction in 12 patients (34%) and complete obstruction in two (5.7%). Although the IPG results from venographically normal and abnormal patients overlapped extensively, mean measurements of venous outflow were significantly lower in the patient population with abnormal venograms (P = 0.052 for Vo; P = 0.0036 for Vo/Vc). In our hands, therefore, upper extremity IPG cannot be used to make clinical decisions about individual patients with VADs, but it can distinguish venographically normal and abnormal populations.

Theory of image formation using the Talbot effect

The information inside each subcell of a two-dimensional periodic object is replicated throughout all the subcells of the unit cell at certain planes. An explicit expression describing the relative phase relationship among the replicated information is derived. From this expression, the wave amplitude at all the subcells caused by the interaction among the information coming from different subcells in the original object is obtained. A computer simulation of gray-level image synthesis using binary substructures and image differentiation is also given.

Nucleotide sequence of a novel arylesterase gene from Vibro mimicus and characterization of the enzyme expressed in Escherichia coli

A gene coding for an arylesterase of Vibrio mimicus was cloned. Sequence determination reveals that the esterase gene has an open reading frame of 600 nucleotides which encodes a protein of M(r) 22,300. The deduced amino acid sequence contain a pentapeptide GDSLS (residues 27-31), which was also found in the phospholipid-cholesterol acyltransferase from Aeromonas hydrophila. Substitution of Ser-29 by alanine or cysteine in the cloned gene abolished the esterase activity in the tributyrin plate assay. On the other hand, the activity was not lost when Ser-31 was changed to alanine. The cloned gene was expressed in Escherichia coli, and the protein purified by a four-step procedure. The purified protein migrated on SDS/PAGE as a single band with an apparent M(r) of 22,100. This enzyme favoured the hydrolysis of several arylesters and was classified as an arylesterase (EC 3.1.1.2). N-Terminal analysis showed that Ser-20 was the first amino acid of the mature secreted protein, suggesting that the N-terminal 19 hydrophobic amino acids served as a signal peptide.

Histological and biomechanical studies of hydroxylapatite implant

Bony defects measuring 12x12x12 millimeters in size were created bilaterally over the proximal end of the femurs of 10 Macaca cyclopis monkeys and implanted with particulate hydroxylapatite. The animals were sacrificed according to a predetermined sequence of post-operative 1, 2, 3, 6, and 8 months. The specimens taken from the implant sites in the two femurs of each animal were chosen randomly either for histological observation or for compressive strength tests under vertical loads. Histological pictures showed only loose fibrous tissue over the interparticular space of the implant site at the first month after surgery. Woven bone could be observed over the basal part of the implant site at the second month. New bone formed over the central part of the implant site at the third month after surgery. Continuing maturation of the bone tissue could be observed over the interparticular space of the implant site until the late stages at the 6th and 8th month after surgery. The results of compressive strength tests were compatible with the histological observations. The value of the elastic modulus was low initially at the first month, but increased gradually with time due to organization of fibrous tissue, condensation of HA particles, and ossification as well as maturation of bone tissue. The value of elastic modulus at the third month was equal to that of cortical bone tissue and even two-fold higher than that of the cortical bone at the eighth month after surgery. These results provide valuable information about the compressive strength of the HA implant in host tissue.

Bilateral mesiodentes of identical twins--a case report

A pair of identical 10-year-old Chinese twins with bilateral mesiodentes of opposite orientation are presented. Three mesiodentes were conical and impacted, while the other one had erupted and was incisiform in shape. All roots of the mesiodentes were completely formed. Intrapair twin comparison showed a high degree of genetically determined concordance, with minor differences subject to environmental influences. The prevalence of mesiodens and rate of monozygotic twins in various ethnic groups are reviewed. Mirror image traits and verification of monozygocity in identical twins are also discussed.