The fabrication of plasmonic Au nanovoid trench arrays by guided self-assembly.

Metallic nanoscale voids can support both localized and propagating plasmons and form plasmonic crystals. However, constructing 1D arrays is crucial for producing plasmonic circuits. In this paper we report the first experimental evidence of plasmons in templated linear arrays of self-assembled structures. Single and multilayer arrays of gold voids have been fabricated by self-assembly of sub-micron polystyrene spheres in V-shaped trenches in silicon, followed by selective area electrodeposition. Angle-dependent dispersion characteristics reveal the existence of localized plasmons.

UV SERS at well ordered Pd sphere segment void (SSV) nanostructures.

Ultraviolet laser excited surface-enhanced Raman scattering was obtained for the first time at the well ordered palladium sphere segment void (SSV) nanostructures, using adenine as the probe molecule, and the UV-SERS enhancement is found to be correlated well with the plasmon absorption of Pd SSVs in the UV region.

Easily coupled whispering gallery plasmons in dielectric nanospheres embedded in gold films.

A new self-aligned robust method for coupling to whispering gallery modes (WGMs) of submicron microspheres utilizes their periodic arrangement without relying on nanopositioned external coupling devices. The microspheres are embedded in a nanostructured gold surface supporting delocalized plasmonic crystal modes that mediate the coupling, and can be tuned by the geometry. Detailed measurements of the angle- and orientation-dependent reflectivity reveal localized plasmonic WGMs whose energies scale with sphere diameter and agree closely with Mie calculations. Coupling between these plasmonic WGMs leads to mode splitting and the formation of plasmonic minibands of a controllable bandwidth.

Psychological aspects of chronic low back pain.

BACKGROUND: Patients with chronic low back pain present physicians with diagnostic and therapeutic problems. Physical treatments tend to have low success rates and it is postulated that this may be because low back pain can be a manifestation of abnormal illness behaviour. METHODS: A structured prospective study determined the prevalence of somatization in a sample of 131 adult patients with chronic low back pain using the Illness Behaviour Questionnaire (IBQ) and the Modified Somatic Perception Questionnaire (MSPQ). The scores on these psychological questionnaires were compared with the blind interpretation of pain distribution drawings and with the results of a mechanical classification of the patient's symptoms and signs. RESULTS: Fifty-four per cent of patients had four or more (out of five) abnormal illness indicators. The MSPQ values for the group were significantly above the control values in the literature. Thirty-two per cent of pain diagrams were thought to be incompatible with an organic cause when assessed by an orthopaedic surgeon and sixty-two per cent when assessed by a psychiatrist. CONCLUSIONS: Psychosocial factors are dominant in the presentation of chronic low back pain in adults and the disorder is not primarily a musculoskeletal one.

Successful control of intractable nausea and vomiting requiring combined ondansetron and haloperidol in a patient with advanced cancer.

Chemically induced nausea and vomiting is a common symptom of advanced cancer effected through stimulation of dopamine (D2) or serotonin (5-HT3) receptors located in the chemoreceptor trigger zone (CTZ). These may be blocked by therapeutic doses of haloperidol and ondansetron, respectively. This case, reporting on a single patient acting as her own control, establishes that combined blockade of these receptors is sometimes required to relieve intractable nausea and vomiting. It also demonstrates the value of clinical review, audit of care, and quality assurance in the palliative care setting.

Communicating with people who request euthanasia.

The subject of euthanasia is widely debated in the medical literature and lay press in terms of morals, anecdotes and medical or legal ethics. This paper approaches the issue from a patient-centred perspectives, giving four case histories to demonstrate widely varied motives or hidden agendas for requesting euthanasia. It concludes with guidelines in an approach to communication which may empower the caregiver when confronted with a patient requesting assisted death or suicide.

Adolescent suicide in orthodontics: results of a survey.

Suicide among adolescents is a psychosocial problem that confronts today's teenagers and society in alarming proportions. The wounds from this tragedy scar adolescents and their families both physically and emotionally. By virtue of a tradition for early treatment and the periodic nature of orthodontic care during critical psychologic development, the orthodontist is in a position to recognize early warning signs of adolescent suicide. A survey of 1000 practicing orthodontists and 54 department chairpersons of orthodontic postgraduate programs assessed the relevance of this issue to the profession, the nature of educational information previously and currently available in orthodontic curricula, and the frequency with which suicidal behavior is noted in orthodontic practice. Guidelines for recognition and intervention are provided. The results indicate that (1) adolescent suicide is of concern to orthodontists, (2) academic information has focused on the general aspects of psychology but not on the recognition and intervention, and (3) 50% of those surveyed have had at least one patient attempt suicide, whereas 25% have had a young patient actually commit suicide.

Isolation of a virus from Mycoplasma pulmonis.

A virus designated mycoplasma virus P1 has been isolated from Mycoplasma pulmonis. The virus infects M. pulmonis strain UAB 6510, and a plaque-forming unit assay has been developed. P1 has a tailed, polyhedral morphology with a head diameter of about 28 nm. Nucleic acid isolated from crude preparations of P1 virus contains double-stranded RNA, suggesting that P1 may be the first example of an RNA-containing mycoplasma virus.

Danazol treatment of advanced prostate cancer: clinical and hormonal effects.

Danazol was administered to 19 patients with advanced prostate cancer. These patients were treated for periods ranging from 3 days to 18 weeks. There were no objective remissions, but three patients (15.8%) had objectively stable disease (N.P.C.P. criteria) with complete pain control for periods ranging 15-18 weeks. Seven patients experienced tumor flare reactions, one requiring withdrawal of treatment and one resulting in rapid clinical deterioration and death. Four other patients died within 3 weeks and, although they were already in the terminal phase of disease when treatment commenced, it is possible that the deaths were treatment related. This study indicates that danazol has only limited activity in the treatment of advanced prostate cancer and is associated with a high incidence of tumor flare reactions with the risk of rapid clinical deterioration.

Structure of eight streptococcal bacteriophages.

Eight phages from groups A, B, C, E, G, and H streptococci were propagated in their own hosts, purified, and examined for morphology; the size, shape, and structure of their extracted nucleic acids was also examined. Electron microscopy showed three types of phage morphology. All eight phages possess linear double-stranded DNAs of molecular weights ranging from 10.5 X 10(6) to 24 X 10(6). Four phages from three different serological groups presented an identical pattern of restriction enzyme fragments. As shown by BAL31 digestion prior to restriction and by reanneling experiments, all but one DNA is circularly permuted. Terminal repetition is also present in six phage DNAs.

Localization of complement component 3 on Streptococcus pneumoniae: anti-capsular antibody causes complement deposition on the pneumococcal capsule.

We have previously shown that complement component 3 (C3) deposited onto encapsulated Streptococcus pneumoniae by anti-capsular antibody (Ab) is a more efficient opsonin in vitro and in vivo than C3 deposited by anti-cell wall Ab (Brown et al., J. Clin. Invest. 69:85-98, 1982). In the present study, we explored the cellular location of C3b molecules that differ in opsonic efficiency by using avidin-ferritin to localize biotinylated Ab and C3 molecules on S. pneumoniae for electron microscopy. Anti-cell wall Ab and C3b molecules deposited by this Ab on unencapsulated S. pneumoniae were localized to S. pneumoniae cell walls. Anti-capsular Ab and C3b deposited by this Ab were seen in clusters on encapsulated S. pneumoniae at a distance from the cell wall. However, no avidin-ferritin staining of encapsulated S. pneumoniae was seen on incubation with biotinyl-anti-cell wall Ab, biotinylated C3 fixed by anti-cell wall Ab, or nonimmune serum containing biotinyl-C3. In each case, uptake of the biotinylated component was proven by radioactivity measurements, since biotinylated Ab and C3 were also radiolabeled with 125I. When avidin-ferritin did not bind to biotinylated components. Ouchterlony analysis indicated that C3 was bound to cell wall components on the encapsulated organisms. Thus, we conclude that, for encapsulated S. pneumoniae, opsonically efficient C3b molecules, deposited by anti-capsular Ab, are located on the S. pneumoniae capsule, whereas the opsonically inefficient C3b molecules deposited by anti-cell wall Ab or nonimmune serum are located on the cell wall. A major reason for the increased virulence of encapsulated compared to unencapsulated S. pneumoniae is that, in the absence of anti-capsular Ab, the S. pneumoniae capsule interferes with the recognition of cell wall-bound C3b molecules by phagocytic cell receptors.

Structural characteristics of tetanolysin and its binding to lipid vesicles.

Tetanolysin binding to lipid vesicles was found to depend on the molar ratio of cholesterol to phospholipid, being low in vesicles containing up to 20 mol% cholesterol and high in vesicles containing more than 33 mol%. High concentrations of purified tetanolysin preparations formed arc- and ring-shaped structures. The structures were not readily detectable in diluted preparations unless incubated with lipid vesicles containing high molar ratios of cholesterol to phospholipid. It is suggested that the toxin is concentrated on the vesicles to local concentrations high enough to form the arcs and rings.

Molecular basis for cytadsorption of Mycoplasma pneumoniae.

Hemadsorbing (HA+) virulent Mycoplasma pneumoniae and spontaneously derived nonhemadsorbing (HA-) avirulent mutants were compared by biochemical and ultrastructural techniques in an attempt to understand the molecular basis for cytadsorption. Lactoperoxidase-catalyzed iodination of intact mycoplasmas indicated that both virulent and avirulent mycoplasmas displayed similar surface protein patterns. A specific external protein, P1 (molecular weight, 165,000), previously implicated as a major ligand mediating attachment, was readily detected in HA+ and HA- mycoplasma strains. However, immunoferritin electron microscopy, with monospecific antibody against P1, revealed that differences in P1 topography existed among these strains. Only virulent mycoplasmas exhibited high concentrations of P1 at the terminal organelle. Avirulent mycoplasmas which possessed P1 showed no P1 clustering at the terminus. Both virulent M. pneumoniae and avirulent P1-containing mutants possessed numerous less dense P1 regions along the mycoplasma surface. Not surprisingly, an HA- mutant lacking P1 exhibited only background immunoferritin labeling. Negative staining of intact mycoplasmas revealed a well-defined, naplike terminus (associated with P1 clusters) confined at the tip of virulent M. pneumoniae. Previous characterization of HA+ virulent and HA- avirulent strains of M. pneumoniae by one- and two-dimensional polyacrylamide gel electrophoresis suggests that identified groups of mycoplasma proteins, lacking in specific HA- mycoplasmas, regulate the physical arrangement of P1 and the ultrastructure of the terminus, thus influencing adherence to the respiratory epithelium and virulence.

Biotinylation of human C3.

Purified human C3 was biotinylated using the biotinyl-N-hydroxysuccinimide imidoester (BNHS). Depending on the input of BNHS, from three to six molecules of biotin were incorporated per C3 molecule. The biotinyl-C3 retained over 90% of its specific hemolytic activity and when bound to sheep erythrocytes maintained its ability to adhere to human C3b receptors. These functions could be blocked by avidin. The biotinyl-C3 was fragmented normally to C3c and C3d in human serum and adsorption with avidin-Sepharose indicated that biotin moities were present in both fragments. Fluorescein-conjugated avidin reacted well with cell-bound biotinyl-C3b and was useful for quantitating C3 fixation by flow cytometry. Ferritin-conjugated avidin was used as a marker to characterize the distribution of biotinyl-C3b on erythrocytes by electron microscopy. These results suggest that biotinyl-C3 and avidin derivatives may be very useful tools for studies of many of the biological functions of C3.

Spiroplasmal viruses: group 1 characteristics.

Virus-like particles of three morphologic groups have been detected by electron microscopy in 90% of spiroplasma strains. In this study, virus-like particles of group 1 (SpV1)--unenveloped rods 230-280 nm by 10-15 nm--were found in 575 of spiroplasmas. SpV1 occurred spontaneously in large numbers in cultures of strains B (corn stunt), G1 (tulip tree flower), BC3 (honeybee), and KC3 (honeybee), respectively; the viruses were isolated and assayed as plaque-forming units, with several of the same strains used as indicators. No virus plaqued on its strain of origin, and all except one (SpV1/BC3) plaqued best on strain BC3. Host range and yields of progeny virus differed. All isolates were identical in morphology, size, and buoyant densities; contained DNA; formed turbid 1.5 to 5.0-mm plaques; produced nonlytic infections and similar one-step growth curves; were inactivated by a single antiserum; had similar kinetics of adsorption and heat inactivation; and demonstrated similar patterns of resistance and sensitivity to a variety of physical and chemical agents, as well as an inability to infect resistant host mutants. SPV1 isolates from diverse host strains apparently share many physicochemical and biological properties, but are not identical in all biological respects.

Mycoplasma pneumoniae infection: role of a surface protein in the attachment organelle.

Attachment of Mycoplasma pneumoniae to host cell by means of a specialized terminus initiates infection. Monoclonal antibodies to a surface protein (Pl) inhibit this process, and react with a region of the tip covered with peplomer-like particles. Since antibodies against the Pl protein are generated by natural and experimental infection and by immunization, the substance may be an important determinant of protective immunity.

The Coupling of Electron Flow to ATP Synthesis in Pea and Maize Mesophyll Chloroplasts : I. INTERACTION OF ADENINE NUCLEOTIDES AND ENERGY TRANSFER INHIBITORS WITH THE COUPLING FACTOR COMPLEX.

The rate of nonphosphorylating electron transport (in the absence of ADP and inorganic phosphate) in well-coupled (ATP/2e(-) = 0.9-1.1) maize mesophyll chloroplasts is not modulated by external pH (6.5-8.5), low levels of ADP or ATP, or energy transfer inhibitors, e.g. triphenyltin and Hg(2+) ions. In contrast nonphosphorylating electron flow in pea chloroplasts is sensitive to alterations in medium pH, and to the presence of adenine nucleotides and energy transfer inhibitors in the assay medium. Although ATP is without effect on the rate of basal electron transport in maize chloroplasts, steady-state proton uptake is stimulated 3- to 5-fold by low levels of ATP. These results suggest that differences may exist in the manner in which the coupling factor complex controls proton efflux from the intrathylakoid space in C(3) and C(4) mesophyll chloroplasts.

Urogenital mycoplasma infections of man: a review with observations on a recently discovered mycoplasma.

Ureaplasma urealyticum organisms (ureaplasmas), Mycoplasma hominis, M. fermentans, M. primatum, M. Salivarium and M. pneumoniae have been isolated from the genitourinary tract. The first two of these microorganisms are found most frequently. M. hominis is a cause of some cases of postpartum and postabortal fever, acute pyelonephritis and pelvic inflammatory disease. Ureaplasmas have been associated with chorioamnionitis, habitual spontaneous abortion, low birthweight, the urethral syndrome in women, and nongonococcal urethritis (NGU) in men; but the difficulty of proving an etiological relationship is emphasized. However, in NGU there is accumulating evidence to indicate that ureaplasmas cause some cases. Some patients suffering from NGU, from whom ureaplasmas, mycoplasmas and chlamydiae cannot be isolated, respond to tetracycline therapy. This has suggested that a tetracycline-sensitive microorganism might be responsible. In this context, the isolation of a glucose-metabolizing mycoplasma from the genitourinary tracts of 2 of 13 men with NGU is of interest. This mycoplasma, serologically different from all other tested, has the structural and biological features of a pathogenic organism.

A newly discovered mycoplasma in the human urogenital tract.

A new mycoplasma, serologically distinct from all other known mycoplasmas, was isolated from urethral specimens from two of thirteen men with non-gonococcal urethritis. Repeatable isolation and propagation was accomplished by use of a special culture medium. The organisms adhered to glass or plastic, erythrocytes, and monkey kidney cells. This property appears to be associated with surface material restricted to the area of a terminal structure of the flask-shaped mycoplasmas. Although the data are insufficient to implicate the new mycoplasmas in human disease, the fact that they are unique, extremely fastidious, and have adherence properties, has stimulated efforts to assess their pathogenicity and possible role in human urogenital disease.