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Revised alpha4 term of lepton g-2 from the Feynman diagrams containing an internal light-by-light scattering subdiagram.

The alpha(4) contribution to the lepton g-2 from a gauge-invariant set of 18 Feynman diagrams containing a light-by-light scattering subdiagram internally has been reevaluated by a method independent of the previous approach. Comparison of two methods revealed a program error in the first version. Correcting this error, the contributions of these 18 diagrams become -0.990 72(10)(alpha/pi)(4) and -4.432 43(58)(alpha/pi)(4) for the electron and muon g-2, respectively. The correction is not large enough to affect the comparison between theory and experiment for the muon g-2, but it does alter the inferred value for the fine structure constant alpha(-1) by 6 ppb.

Elementary Particles↗

A dominant mutation in the pea PHYA gene confers enhanced responses to light and impairs the light-dependent degradation of phytochrome A.

Phytochrome A (phyA) is an important photoreceptor controlling many processes throughout the plant life cycle. It is unique within the phytochrome family for its ability to mediate photomorphogenic responses to continuous far-red light and for the strong photocontrol of its transcript level and protein stability. Here we describe a dominant mutant of garden pea (Pisum sativum) that displays dramatically enhanced responses to light, early photoperiod-independent flowering, and impaired photodestruction of phyA. The mutant carries a single base substitution in the PHYA gene that is genetically inseparable from the mutant phenotype. This substitution is predicted to direct the replacement of a conserved Ala in an N-terminal region of PHYA that is highly divergent between phyA and other phytochromes. This result identifies a region of the phyA photoreceptor molecule that may play an important role in its fate after photoconversion.

Amino Acid Sequence↗

The C-terminal domain of light-harvesting chlorophyll-a/b-binding protein is involved in the stabilisation of trimeric light-harvesting complex.

Light-harvesting chlorophyll a/b-binding protein (LHCP) can be reconstituted with pigments in detergent solution to yield stable monomeric light-harvesting chlorophyll a/b complex (LHCII). This reconstitution is not significantly affected when up to ten amino acids are deleted on the C-terminus of LHCP or when a tryptophan, which is 11 positions from the C terminus (W222), is exchanged with other amino acids [Paulsen, H. & Kuttkat, A. (1993) Photochem. Photobiol. 57, 139-142]. Here we show that the exchange of W222 with histidine or glycine completely abolishes the ability of the protein to assemble into trimeric LHCII, either upon reconstitution of monomeric complexes in detergent solution or upon insertion into isolated thylakoids. It is concluded that part of the hydrophilic domain on the C-terminus of LHCP, although not essential for the formation of stable monomeric LHCII, is involved in trimer formation. The different degree to which various amino acids in place of W222 affect trainer formation suggests that a hydrophobic amino acid is needed in this position.

Amino Acid Sequence↗

Dynamic light use and protection from excess light in upper canopy and coppice leaves of Nothofagus cunninghamii in an old growth, cool temperate rainforest in Victoria, Australia.

Responses to simulated sunflecks were examined in upper canopy and coppice leaves of Nothofagus cunninghamii growing in an old-growth rainforest gully in Victoria, Australia. Shaded leaves were exposed to a sudden increase in irradiance from 20 to 1500 micromol m(-2) s(-1). Gas exchange and chlorophyll fluorescence were measured during a 10 min simulated sunfleck and, in the ensuing dark treatment, we examined the recovery of PS II efficiency and the conversion state of xanthophyll cycle pigments. Photosynthetic induction was rapid compared with tropical and northern hemisphere species. Stomatal conductance was relatively high in the shade and stomata did not directly control photosynthetic induction under these conditions. During simulated sunflecks, zeaxanthin was formed rapidly and photochemical efficiency was reduced. These processes were reversed within 30 min in coppice leaves, but this took longer in upper canopy leaves. Poor drought tolerance and achieving a positive carbon balance in a shaded canopy may be functionally related to high stomatal conductance in the shade in N. cunninghamii. The more persistent reduction in photochemical efficiency of upper canopy leaves, which means less efficient light use in subsequent shade periods, but stronger protection from high light, may be related to the generally higher irradiance and longer duration of sunflecks in the upper canopy, but potentially reduces carbon gain during shade periods by 30%.

Carbon↗

High dose chemotherapy in light chain or light and heavy chain deposition disease.

BACKGROUND: Conventional chemotherapy for myeloma yield unsatisfactory results in light and/or heavy chain deposition disease [(H)CDD] Because of the well-established dose-response effect of high dose melphalan in multiple myeloma, aiming to dramatically reduce the pathogenic monoclonal immunoglobulin (MIg) level, high dose therapy is a tempting alternative approach. METHODS: We treated 11 young patients with L(H)CDD by high dose therapy with the support of autologous blood stem cell transplantation. All had renal symptoms, including four who required dialysis and seven who had various, mainly cardiac, extrarenal manifestations. RESULTS: No toxic deaths occurred. A decrease in the MIg level was observed in eight patients, with complete disappearance from serum and urine in six cases. Improvement in manifestations related to MIg deposits were observed in six patients, including renal, cardiac, and hepatic responses in 4/11, 4/4, and 2/2 cases, respectively. Histologic regression of MIg deposits was documented in cardiac, hepatic, and skin biopsies. In contrast, examination of the kidney still showed light chain deposits in one patient who had renal transplantation 3 years after high dose therapy, at a time when he was in persisting remission. Within a median follow-up of 51 months, three patients were retreated because of multiple myeloma relapse, of whom one died and one required hemodialysis, and renal function secondarily deteriorated in a patient who had resistant multiple myeloma. Otherwise, no manifestations related to MIg deposits occurred or recurred in any patient. CONCLUSION: Present results of this retrospective study argue in favor of a benefit of high dose therapy with stem cell support in young patients with L(H)CDD.

Adult↗

After-polymerization of visible light activated resins: surface hardness vs. light source.

The Wallace hardness of four visible light activated resins (Durafill, Heliosit, Silux and Visio-Dispers) was investigated at different times from 1 min and 35 s up to 60 min after start of irradiation. The prevailing part of the increase in surface hardness was found within the first few min after irradiation and this pattern was similar in all resins independent of light source.

Chemical Phenomena↗

Covalent immunoglobulin assembly in vitro: reactivity of light chain covalent dimers (L2) and blocked light chain monomers.

Covalent light chain dimers (L2) and cysteine-blocked L chain monomers readily react with partially reduced heavy (H) chains. A rapid disappearance of these blocked L chain species is followed by the appearance of covalent intermediates-HL, H2, and H2L-leading to fully assembled H2L2. The mechanism of initial disulfide bond formation between heavy and light chains is disulfide interchange.

Bence Jones Protein↗

Phototropin blue light receptors and light-induced movement responses in plants.

Two blue light receptors in Arabidopsis, termed phot1 and phot2, which contain flavin chromophores and have intrinsic protein kinase activity, participate in several physiological processes. Lin looks at the genetic evidence regarding how these photoreceptors mediate blue light-induced phototropism, chloroplast relocalization, and opening of the stomatal aperture.

Arabidopsis↗

The mesangium as a target for glomerulopathic light and heavy chains: pathogenic considerations in light and heavy chain-mediated glomerular damage.

Certain structurally abnormal light and heavy chains are known to be nephrotoxic and alter mesangial homeostasis producing pathological alterations. Many of the mechanisms involved in light chain-mesangial interactions have been deciphered using an in vitro model, providing a framework for understanding the sequence of events that leads to irreversible glomerular changes and eventually renal failure. The molecular events involved in the pathogenesis of these disorders are now for the most part well-established. These studies have delineated the sequence of steps involved and crucial events have been determined. An animal model is being developed which will undoubtedly contribute significantly to validate the information that has been obtained from the in vitro models. The present chapter will address the pathogenesis of these disorders with an emphasis on highlighting crucial steps possibly amenable to therapeutic intervention to stop or ameliorate adverse consequences leading to irreversible changes.

Amyloidosis↗

Mechanisms of photodynamic inactivation of herpes simplex viruses: comparison between methylene blue, light plus electricity, and hematoporhyrin plus light.

Herpes simplex virus (HSV) types 1 and 2 have been inactivated in vitro using low concentrations of methylene blue (MB), light (lambda) plus electricity (E), or hematoporphyrin derivative (HPD) plus lambda. Both techniques introduce single strand interruptions into viral DNA, but do not make double strand ruptions into viral DNA, but do not make double strand breaks. MB, lambda plus E-treated virions adsorb normally to and penetrate susceptible cells, whereas HSV inactivated with HPC and light does not. This difference is emphasized by the induction of new viral and cell DNA synthesis after infection with MB, lambda plus E-treated virions, whereas only cell, DNA but no HSV DNA, is made subsequent to HPD and lambda exposure. These observations reflect disparate mechanisms of viral inactivation. A block(s) in viral maturation, subsequent to viral DNA synthesis, occurs as a result of treatment with MB, lambda and E, whereas HPD plus lambda-treated particles fail to enter a susceptible cell, and therefore do not initiate an infection.

Cell Survival↗

An evaluation of lenses designed to block light emitted by light-curing units.

A number of protective lenses are available to prevent ocular injury from wavelength spectrum generated by visible light. Four of the five lenses tested absorbed virtually all of the radiation transmitted in the 200 to 800 nm level. Protective eyewear should be used when blue and ultraviolet light-curing units are involved.

Composite Resins↗

Evaluation of light transmission characteristics of protective eyeglasses for visible light-curing units.

Eyeglasses with protective filters are recommended for users of visible light-curing units to decrease the intensity of blue light reaching the eyes. The transmission curves of 20 commercially available filter glasses are obtained. The irradiance from eight curing units through these glasses is measured. The reduction in irradiance through the filter glasses is related to the transmission curves.

Evaluation Studies as Topic↗

Amino acid sequences of antibody light chain variable regions of pedigreed rabbits: kappa light chain K49-501 (allotype b4 anti-streptococcal group A-variant polysaccharide antibody).

The amino acid sequence of positions 1--150 of a light chain, isolated from another monoclonal rabbit anti-streptococcal group A-variant polysaccharide antibody, was determined. The analysis was performed with 2 mumol of polypeptide chain, using a grossly modified Beckman 890B sequenator. This sequence stretch accounts for the whole variable region and a considerable part of the constant region at a total length of 218 amino acids. This allotype b4 light chain was isolated from a non-precipitating, end-group-specific antibody with a KD = 1.3 X 10(-5)M. This brings the present number of totally known rabbit VL sequences of antigen elicited antibodies to 21. A comparison of these 21 sequences reveals a building plan of ribbit VL homologous to that of human and murine VL regions. The observed variability does follow a pattern of linked amino acid substitutions, indicating that this information must be contained in the germ-line of the rabbit in the form of multiple VL region genes. This conclusion, however, does not rule out the occasional variant being due to somatic rearrangement. Finally, this comparison reveals that the joining peptide between positions 96--110 is also a separate entity in rabbit VL region sequences.

Amino Acid Sequence↗

Oligoclonal immunoglobulins, light chain ratios and free light chains in cerebrospinal fluid and serum from patients affected with various neurological diseases.

Several immunological parameters, of which the most important are the kappa-lambda ratios, the presence of free light chains and the double ring formation for kappa-chains in single radial immunodiffusion, were investigated in the cerebrospinal fluid and serum of patients affected with different neurological diseases. Parallels were run either with multiple sclerosis or subacute sclerosing panencephalitis. There seems to be a correlation between the frequency of the presence of free light chains and the degree of severity of the immunological process.

Humans↗

Restoration-enamel interface with argon laser and visible light polymerization of compomer and composite resin restorations: a polarized light and scanning electron microscopic in vitro study.

This polarized light (PL) and scanning electron microscopic (SEM) in vitro study investigated the effect of argon laser (AL) and visible light (VL) polymerization on the interfaces between compomer and composite resin restorations and the enamel cavosurfaces. Surface topography by SEM revealed a smooth transition between the restorative materials and adjacent enamel surfaces with no microspaces between the restorations and enamel surfaces. The enamel surfaces showed relatively smooth surface coatings with AL curing compared with exposure of etched prism endings with VL curing. The restoration-enamel interface by PL showed an intimate relationship between the restorative materials and the cavosurface enamel. No differences were found between AL and VL polymerization. With the restoration-enamel interface by SEM, compomers and composite resins were adapted closely to the cavosurface enamel and tags of restorative material protruded into the adjacent cavosurface enamel. Both VL and AL polymerization of compomers and composite resin restorations in vitro produced closely adapted restorations with intimate restoration-enamel interfaces. Such restoration-enamel interfaces may provide a certain degree of resistance against secondary caries formation, and this may be enhanced by the caries protective effect of argon laser irradiation.

Adhesives↗

Turbidimetric measurement of Bence-Jones proteins using antibodies against free light chains of immunoglobulins. An artifact caused by different polymeric forms of light chains.

The different polymeric forms of free kappa and lambda light chains from urines of two myeloma patients were separated by gel filtration. When samples containing kappa chains in equal protein concentration were quantified by turbidimetry with anti-free kappa chain antibodies, two out of three samples reacted much less sensitively than the third sample. When analysed with SDS-polyacrylamide gel electrophoresis in conditions dissociating non-covalent but not covalent linkages, these two samples contained monomeric light chains, whereas the third sample contained dimers.

Antibodies↗

Improvements to light transmittance in light-cured composite resins by the utilisation of low refractive index dimethacrylates.

In an effort to improve the light transmittance of light-cured composite resins while avoiding degradation of their physical properties, 4 dimethacrylates having low refractive indices and a bulky backbones such as alicyclic or fluorine-substituted bisphenol groups were synthesized. The depths of cure and physical properties of 6 experimental composite resins containing these new monomers were, then, examined and compared to those of 3 control composite resins containing UDMA, BisMEPP, or BisGMA. The depths of cure of the experimental group containing the synthesized monomers were greater than those of the control group with the exception of the composite containing UDMA. The depth of cure increased as the difference between the refractive indices of the matrix monomer and silica filler decreased. The physical properties of 2 composites in the experimental group were comparable to those of the control group. The matrix monomers of these 2 composites were a mixture of 4,8-dimethacryloxymethylene tricyclo [5.2.1.0] decane or 2,2-bis (4-methacryloxyethoxy phenyl) hexafluoropropane and TEGDMA in a molar ratio of 1/1.

Composite Resins↗

[Topical photodynamic therapy in basal and squamous cell carcinoma and penile Bowen's disease with 20% aminolevulinic acid, and exposure to red light and infrared light].

Photodynamic therapy (PDT) is a noninvasive selective therapy for a specific group of skin tumors. 5-aminolevulinic acid 20% in a water-in-oil cream base was applied to the tumors as a photosensitizer and was followed after 12 hours by exposure to a high output light source emitting red (585-720 nm; 150 mW/cm2) and near infrared irradiation (1.25-1.6 mm; 50 mW/cm2) for 10-15 minutes (VersaLight, incoherent filtered light source). Complete responses were achieved after 1-3 treatments in 26/31 lesions of superficial or small nodular basal cell carcinoma (BCC) and 4/5 in superficial, squamous cell carcinoma (SCC) lesions. There was a patient with Bowen's disease of the penis. Follow-up was for 12-24 months. This noninvasive, nearly painless treatment gives excellent therapeutic and cosmetic results. Our data show its efficacy for certain subtypes of BCC, SCC and Bowen's disease. Further studies will determine the exact cure and recurrence rates with this modality and compare it to other modes of skin cancer therapy.

Administration, Topical↗