Energy barriers and cooperative motion at the surface of freestanding glassy polystyrene films.

We investigate the near-surface relaxation of freestanding atactic polystyrene films with molecular dynamics simulations. As in previous coarse-grained simulations, relaxation times for backbone segments and phenyl rings are linked to their bulk relaxation times via a power-law coupling relation. Variation of the coupling exponent with distance from the surface is consistent with depth-dependent activation barriers. We also quantify a reduction in dynamical heterogeneity at the interface, which can be interpreted in the framework of cooperative models for glassy dynamics.

Bi-Arrhenius Diffusion and Surface Trapping of

We report measurements of the diffusion rate of isolated ion-implanted ^{8}Li^{+} within ∼120 nm of the surface of oriented single-crystal rutile TiO_{2} using a radiotracer technique. The α particles from the ^{8}Li decay provide a sensitive monitor of the distance from the surface and how the depth profile of ^{8}Li evolves with time. The main findings are that the implanted Li^{+} diffuses and traps at the (001) surface. The T dependence of the diffusivity is described by a bi-Arrhenius expression with activation energies of 0.3341(21) eV above 200 K, whereas at lower temperatures it has a much smaller barrier of 0.0313(15) eV. We consider possible origins for the surface trapping, as well the nature of the low-T barrier.

Inhibition of hepatic metastasis in mice treated with cell-binding domain of human fibronectin and angiogenesis inhibitor TNP-470.

BACKGROUND: To prevent tumor metastasis, we administered the cell-binding domain of fibronectin, in combination with the angiogenesis inhibitor TNP-470, to mice with hepatic metastasis. We then assessed the prevention of tumor metastasis resulting from the inhibition of adhesive interactions and the inhibition of angiogenesis. METHODS: A hepatic metastasis model was created by injecting 1 x 10(3) colon 26/TC-1 cells into the anterior mesenteric vein of CDF1 mice. The cell-binding domain obtained from fibronectin included the Arg-Gly-Asp (RGD) sequence. A fibronectin-binding domain (FND)-treated group, an FND plus TNP-470 group, and a control group were established. The animals were killed 4 weeks after the injections of the treatment agents had been completed and the number of metastatic liver nodules was counted. In a simultaneous experiment with the same design, the mice were not killed at 4 weeks, and their survival was observed. RESULTS: The mean number of nodules in the FND plus TNP-470 group was significantly lower than that in the control group (P = 0.019337). The inhibition rate was 51% in the FND group, 60% in the FND 10 micrograms plus TNP-470 10 mg/kg group, and 64% in the FND 10 micrograms plus TNP-470 100 mg/kg group compared with the control group. Mice from the FND group that were not killed died after 6-8 weeks, but mice from the FND plus TNP-470 group died after 8-12 weeks. CONCLUSION: The cell-binding domain of fibronectin may, potentially, be an effective form of antiadhesive therapy that competes with native adhesion molecules and blocks adhesion during the metastatic process. When the cell-binding domain of fibronectin is combined with TNP-470 to inhibit angiogenesis, more effective inhibition of metastatic tumor growth and prolongation of survival can be achieved than after treatment with the cell-binding domain alone.

Pain, photophobia, and retinal and optic nerve function after phacoemulsification with intracameral lidocaine.

OBJECTIVE: To evaluate differences in pain, photophobia, retinal and optic nerve function in test eyes given intracameral lidocaine compared with control eyes given intracameral saline after phacoemulsification under topical anesthesia. DESIGN: Prospective paired-eye intervention study with random treatment allocation. PARTICIPANTS: Thirty eyes of 15 patients underwent cataract surgery in both eyes under topical anesthesia. INTERVENTION: The first eye of each patient was randomly assigned to either 0.5 ml preservative-free 2% intracameral lidocaine or 0.5 ml of intracameral sterile saline. Within 5 months, the second eye automatically received intracameral saline if the first eye received intracameral lidocaine or vice versa. MAIN OUTCOME MEASURES: The duration of surgery was recorded. Immediately after surgery, each patient was asked to evaluate the degree of pain and photophobia experienced during surgery using a nominal scale. In addition, in five patients, electroretinography (ERG) and visual evoked response (VER) were performed within 1 week before surgery, immediately after surgery, and 1 day after surgery. Amplitudes and latencies were calculated. RESULTS: There was no difference in the duration of surgery comparing test eyes given intracameral lidocaine with control eyes given sterile saline (P = 0.81). There was no significant difference in the level of pain reported when comparing test eyes given intracameral lidocaine with control eyes (P = 1.00). None of the patients reported any significant difference in photophobia between their two eyes (P = 1.00). When comparing ERG measurements, test eyes given intracameral lidocaine did not show any significant decrease in ERG amplitudes or prolonged latencies compared with control eyes. When comparing VER measurements, test eyes given intracameral lidocaine did not show any increase in P1 latencies compared with control eyes (P = 0.31). When evaluating all postoperative ERG results 1 day after surgery, there was a suggestion of improved cone function. CONCLUSIONS: Although intracameral lidocaine does not depress retinal or optic nerve function, the addition of intracameral lidocaine to topical anesthesia during phacoemulsification does not significantly reduce intraoperative pain or photophobia.

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

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

Regulatory issues in pain management.

Patients commonly are left to suffer from pain that affects their daily lives. The prevalence of undertreated, moderate to severe pain is a public health problem in many countries, including the United States. In many cases, opioids should be the mainstay for the treatment of this level of pain, but they often are not used or are underdosed. One of the reasons for this underuse most cited by health care professionals is their fear of sanctions by their governing boards, law enforcement, or their misunderstanding of the laws and regulations governing the use of these controlled substances. This article reviews some of the relevant issues of the regulation of controlled substances, updates the reader about the laws, and provides guidance to practitioners about the appropriate use of controlled substances, especially opioids, to manage pain.

Analysis of genetic elements controlling Staphylococcus aureus lrgAB expression: potential role of DNA topology in SarA regulation.

Penicillin-induced killing and murein hydrolase activity in Staphylococcus aureus are dependent on a variety of regulatory elements, including the LytSR two-component regulatory system and the virulence factor regulators Agr and Sar. The LytSR effects on these processes can be explained, in part, by the recent finding that a LytSR-regulated operon, designated lrgAB, affects murein hydrolase activity and penicillin tolerance. To examine the regulation of lrgAB expression in greater detail, we performed Northern blot and promoter fusion analyses. Both methods revealed that Agr and Sar, like LytSR, positively regulate lrgAB expression. A mutation in the agr locus reduced lrgAB expression approximately sixfold, while the sar mutation reduced lrgAB expression to undetectable levels. cis-acting regulatory elements involved in lrgAB expression were identified by fusing various fragments of the lrgAB promoter region to the xylE reporter gene and integrating these constructs into the chromosome. Catechol 2,3-dioxygenase assays identified DNA sequences, including an inverted repeat and intrinsic bend sites, that contribute to maximal lrgAB expression. Confirmation of the importance of the inverted repeat was achieved by demonstrating that multiple copies of the inverted repeat reduced lrgAB promoter activity, presumably by titrating out a positive regulatory factor. The results of this study demonstrate that lrgAB expression responds to a variety of positive regulatory factors and suggest that specific DNA topology requirements are important for optimal expression.

Purification and cloning of an apoptosis-inducing protein derived from fish infected with Anisakis simplex, a causative nematode of human anisakiasis.

While investigating the effect of marine products on cell growth, we found that visceral extracts of Chub mackerel, an ocean fish, had a powerful and dose-dependent apoptosis-inducing effect on a variety of mammalian tumor cells. This activity was strikingly dependent on infection of the C. mackerel with the larval nematode, Anisakis simplex. After purification of the protein responsible for the apoptosis-inducing activity, we cloned the corresponding gene and found it to be a flavoprotein. This protein, termed apoptosis-inducing protein (AIP), was also found to possess an endoplasmic reticulum retention signal (C-terminal KDEL sequence) and H2O2-producing activity, indicating that we had isolated a novel reticuloplasimin with potent apoptosis-inducing activity. AIP was induced in fish only after infection with larval nematode and was localized to capsules that formed around larvae to prevent their migration to host tissues. Our results suggest that AIP may function to impede nematode infection.

Identification of N(omega)-carboxymethylarginine as a novel acid-labileadvanced glycation end product in collagen.

Collagen undergoes continuous non-enzymatic glycation during its long life period. The products resulting from the glycation reaction, so-called advanced glycation end products (AGEs), were regarded as potential pathogens of various diseases such as diabetic complications. Although several AGEs were identified from acid hydrolysates of glycated collagen, the major AGE(s) responsible for the diseases have not yet been fully characterized. Moreover, acid-labile constituents were decomposed during acid hydrolysis. To investigate these AGEs, we used the enzymatic hydrolysis method [Bensusan, Dixit and McKnight (1971) Biochim. Biophys. Acta 251, 100-108]. As a result, an acid-labile unknown compound was discovered from the digested glycated collagen. We identified this compound as N(omega)-carboxymethylarginine (CMA) by matrix-assisted laster-desorption ionization-MS and NMR. CMA gradually increased in collagen during incubation with glucose and the yield reached about 8 mol/mol of collagen, which is 100 times higher than that of pentosidine. This result suggests that CMA is a major AGE in collagen.

Expression and regulation of a gene encoding neural recognition molecule NB-3 of the contactin/F3 subgroup in mouse brain.

NB-3 is a neural recognition molecule which is a member of contactin/F3 subgroup in the immunoglobulin superfamily. We report here the developmental expression pattern and localization of NB-3 mRNA in mouse brain, determination of the NB-3 gene organization and identification of the promoter region. We also describe a splicing isoform of mouse NB-3. Mouse NB-3 exhibited 96% identity with rat NB-3 at the amino acid sequence level. The splicing isoform lacked the amino acid residues between 62 and 78 of the original NB-3, which constituted a part of the first immunoglobulin-like domain. The expression of NB-3 mRNA was evident after birth, reaching a maximum at the postnatal seventh day, and declined thereafter in the cerebrum, whereas the mRNA increased in the cerebellum to adulthood. In situ hybridization demonstrated that NB-3 mRNA was preferentially expressed in the accessory olfactory bulb, layers II/III and V of the cerebral cortex, piriform cortex, anterior thalamic nuclei, locus coeruleus of the pons and mesencephalic trigeminal nucleus, and in Purkinje cells of the cerebellum. The mouse NB-3 gene consisted of 23 exons spanning more than 130kb. The overall organization of the gene was similar to those of the F11, axonin-1 and TAX-1 genes of the subgroup. By reporter gene analysis with the 5'-flanking region of the gene, we found a basal promoter activity in the 1.2kb fragment upstream of the putative transcription initiation site. This study provides a basis for elucidating the biological significance of the contactin/F3 subgroup molecules.

The Staphylococcus aureus lrgAB operon modulates murein hydrolase activity and penicillin tolerance.

Previous studies in our laboratory have shown that the Staphylococcus aureus LytSR two-component regulatory system affects murein hydrolase activity and autolysis. A LytSR-regulated dicistronic operon has also been identified and shown to encode two potential membrane-associated proteins, designated LrgA and LrgB, hypothesized to be involved in the control of murein hydrolase activity. In the present study, a lrgAB mutant strain was generated and analyzed to test this hypothesis. Zymographic and quantitative analysis of murein hydrolase activity revealed that the lrgAB mutant produced increased extracellular murein hydrolase activity compared to that of the wild-type strain. Complementation of the lrgAB defect by providing the lrgAB genes in trans restored the wild-type phenotype, indicating that these genes confer negative control on extracellular murein hydrolase activity. In addition to these effects, the influence of the lrgAB mutation on penicillin-induced lysis and killing was examined. These studies demonstrated that the lrgAB mutation enhanced penicillin-induced killing of cells approaching the stationary phase of growth, the time at which the lrgAB operon was shown to be maximally expressed. This effect of the lrgAB mutation on penicillin-induced killing was shown to be independent of cell lysis. In contrast, the lrgAB mutation did not affect penicillin-induced killing of cells growing in early-exponential phase, a time in which lrgAB expression was shown to be minimal. However, expression of the lrgAB operon in early-exponential-phase cells inhibited penicillin-induced killing, again independent of cell lysis. The data generated by this study suggest that penicillin-induced killing of S. aureus involves a novel regulator of murein hydrolase activity.

Survey of analgesic use for nonmalignant pain in long-term care facilities in southern California.

OBJECTIVE: Many residents in long-term care facilities experience nonmalignant pain, and analgesic therapy is often inadequate in this setting. We examined the management of chronic nonmalignant pain in elderly nursing home residents. DESIGN: Retrospective chart review. SETTING: Forty skilled nursing facilities in southern California. PARTICIPANTS: Residents with a diagnosis of noncancer pain who were receiving a regular regimen of prescribed analgesics. MEASUREMENTS: The following information was recorded: demographic data, specific diagnosis for pain medication, all analgesics in current use by the resident, whether a pain rating score was available for the resident and, if so, the current score. RESULTS: Of the 3400 resident charts screened, 381 residents (11.2%) met the criteria for inclusion in the study. There were 443 diagnoses for chronic nonmalignant pain, primarily arthritis and other musculoskeletal disorders. Of 510 prescriptions for analgesics, 52% were for acetaminophen or nonsteroidal antiinflammatory medications. Centrally acting analgesics, primarily opioids, accounted for 48% of all prescriptions. Approximately three-fourths of opioid prescriptions were for fixed-dose combinations with acetaminophen, and 15% were for long-acting opioids. Pain scores were not recorded on any of the residents' charts. CONCLUSION: Nonmalignant pain in these elderly nursing home residents was often associated with musculoskeletal disorders and was not assessed systematically. Without routine pain assessments, it is not possible to determine whether the residents' pain was being treated adequately by the analgesics prescribed. We recommend a multidisciplinary approach to the institution of pain assessment and management guidelines in long-term care facilities.

Opposing roles of the Staphylococcus aureus virulence regulators, Agr and Sar, in Triton X-100- and penicillin-induced autolysis.

The regulation of murein hydrolases is a critical aspect of peptidoglycan growth and metabolism. In the present study, we demonstrate that mutations within the Staphylococcus aureus virulence factor regulatory genes, agr and sar, affect autolysis, resulting in decreased and increased autolysis rates, respectively. Zymographic analyses of these mutant strains suggest that agr and sar exert their effects on autolysis, in part, by modulating murein hydrolase expression and/or activity.

Molecular cloning and characterization of mouse ficolin-A.

A novel ficolin-related gene was isolated from the mouse liver lambda ZAPII cDNA library. The protein encoded by this gene consists of both collagen- and fibrinogen-like domains, which are common features of the ficolin family, and was named mouse ficolin-A. The amino acid sequence of mouse ficolin-A is 60.2, 59.8, 59.8, and 59.6% identical to those of porcine ficolin-alpha, -beta, human ficolin-1, and EBP-37/P35, respectively. Northern blot analysis showed that mRNA of mouse ficolin-A is highly expressed in liver and spleen. Immunoblot analysis using an anti-mouse ficolin-A antiserum showed that mouse ficolin-A is a plasma protein with binding activity to elastin and GlcNAc.

Overproduction of Mpd2p suppresses the lethality of protein disulfide isomerase depletion in a CXXC sequence dependent manner.

The third multicopy suppressor gene of the PDI1 deletion from Saccharomyces cerevisiae, MPD2, was isolated and characterized. The MPD2 gene encodes a protein with a putative signal sequence, ER retention signal, and a disulfide isomerase active site like sequence. The amino acid sequence around the active site like sequence is similar to the thioredoxin-like domains of PDI and PDI related proteins, although the similarity is comparatively low. A delta-pdi1 strain over-producing Mpd2p showed slow growth and was sensitive to 1 mM dithiothreitol. Mpd2p can be detected in wild type cells and is a glycoprotein. Although the MPD2 gene was not essential for growth, overexpression of the gene partially restored the maturation defect of carboxypeptidase Y caused by the PDI1 deletion. Mutagenesis analysis revealed that Mpd2p can compensate for the loss of PDI with its CXXC sequence.