Torsion stiffness of a protein pair determined by magnetic particles

We demonstrate the ability to measure torsion stiffness of a protein complex by applying a controlled torque on a magnetic particle. As a model system we use protein G bound to an IgG antibody. The protein pair is held between a magnetic particle and a polystyrene substrate. The angular orientation of the magnetic particle shows an oscillating behavior upon application of a rotating magnetic field. The amplitude of the oscillation increases with a decreasing surface coverage of antibodies on the substrate and with an increasing magnitude of the applied field. For decreasing antibody coverage, the torsion spring constant converges to a minimum value of 1.5 × 10(3) pN·nm/rad that corresponds to a torsion modulus of 4.5 × 10(4) pN·nm(2). This torsion stiffness is an upper limit for the molecular bond between the particle and the surface that is tentatively assigned to a single protein G-IgG protein pair. This assignment is supported by interpreting the measured stiffness with a simple mechanical model that predicts a two orders of magnitude larger stiffness for the protein G-IgG complex than values found for micrometer length dsDNA. This we understand from the structural properties of the molecules, i.e., DNA is a long and flexible chain-like molecule, whereas the antibody-antigen couple is orders of magnitude smaller and more globular in shape due to the folding of the molecules.

Spectrofluorimetric method for determination of citalopram in bulk and pharmaceutical dosage forms

A simple accurate, sensitive reproducible spectrofluorimetric method was developed for the analysis of citalopram in pure and pharmaceutical dosage form. Citalopram showed strong native fluorescence in 0.05 M sulphuric acid having excitation at 239 nm and emission at 300 nm. All parameters like the effect of different solvents, pH, dilutions, reaction time, temperature and effect of excipients were thoroughly investigated. The calibration graph was linear in the range from 0.100 to 0.900 μg/ml. The proposed method was statistically validated and successfully applied for analysis of tablet dosage forms. The percentage recovery was found to be between 99.08% to 99.28%.

Giant lactating adenoma of the breast

Lactating adenoma is one of the breast tumours associated with pregnancy. A case of lactating adenoma, unusual on account of its huge size, is presented. Large size and history of rapid growth can lead to a mistaken diagnosis of malignancy. A review of the literature of this particular tumour with the different views on its histogenesis and the differential diagnoses are also discussed.

A rare potentially treatable cause of bilateral optic disc swelling

Rapid onset bilateral optic disc swelling generally indicates an intracranial problem-that is, papilloedema. However, when there is also visual loss, disease affecting the optic nerves themselves must be considered. We present the diagnostic problem of a patient with optic disc swelling and progressive visual loss. Investigations finally revealed hypocalcaemia secondary to primary hypoparathyroidism. With treatment a marked improvement in vision occurred. This reversible rare cause of optic disc swelling should not be forgotten.

Chiral confinement in quasirelativistic Bose-Einstein condensates

In the presence of a laser-induced spin-orbit coupling an interacting ultracold spinor Bose-Einstein condensate may acquire a quasirelativistic character described by a nonlinear Dirac-like equation. We show that as a result of the spin-orbit coupling and the nonlinearity the condensate may become self-trapped, resembling the so-called chiral confinement, previously studied in the context of the massive Thirring model. We first consider 1D geometries where the self-confined condensates present an intriguing sinusoidal dependence on the interparticle interactions. We further show that multidimensional chiral confinement is also possible under appropriate feasible laser arrangements, and discuss the properties of 2D and 3D condensates, which differ significantly from the 1D case.

C3aR inhibition reduces neurodegeneration in experimental lupus

Complement activation is an important aspect of systemic lupus erythematosus. In this study we investigated the role of C3a/C3a receptor (R) signaling in brains of the lupus model, MRL/lpr mice, by treating the mice with C3aR antagonist (a) from 13 to 19 weeks of age. C3aR mRNA (0.2 +/- 0.027 versus 0.56 +/- 0.19) and protein (0.16 +/- 0.09 versus 0.63 +/- 0.19) expression was increased in MRL/lpr brains compared with MRL+/+ controls. Apoptosis, a key feature in lupus brain, was significantly reduced by C3aRa treatment, as assessed by DNA laddering, TUNEL staining and caspase3 activity (48% of MRL/lpr mice). mRNA expression of proinflammatory molecules that cause apoptosis, TNFalpha (0.33 +/- 0.07 versus 0.15 +/- 0.1), MIP2 (3.8 +/- 1.3 versus 1.7 +/- 0.6), and INFgamma (4.8 +/- 1.0 versus 2.07 +/- 1.28) are reduced in MRL/lpr brains with C3aRa treatment. In line with these results, Western blotting demonstrates the significant increase in phosphorylation of survival molecules Akt and Erk, decrease in PTEN and reduced iNOS expression. INFgamma receptor (R) and AMPA-GluR1 co-localized, and concomitant with reduced INFgammaR expression, AMPAGluR1 expression was also decreased by C3aR antagonist. All of these variables that modulate neuronal excitability and regulate synaptic plasticity are C3aR dependent in the MRL/lpr brains and suggest a potential therapeutic role for C3aR inhibition in CNS lupus.

Multiple sclerosis risk in radiologically uncovered asymptomatic possible inflammatory-demyelinating disease

BACKGROUND

Natural history of patients with incidentally discovered lesions that fulfill magnetic resonance imaging (MRI) criteria for multiple sclerosis (MS) in the absence of objective clinical symptoms suggestive of central nervous system (CNS) inflammatory-demyelinating disease is not well defined.

OBJECTIVE

We evaluated the risk of developing symptomatic MS in patients with radiologically uncovered asymptomatic possible inflammatory-demyelinating disease (RAPIDD).

METHODS

We identified and longitudinally followed a cohort of 22 patients from two tertiary care MS centers: Istanbul University, Cerrahpasa School of Medicine, Istanbul, Turkey, and Mayo Clinic, Rochester, Minnesota, after an initial MRI study fulfilling the Barkhof-Tintore MRI criteria completed for other reasons unrelated to MS.

RESULTS

Eight of 22 patients developed an objective clinical symptom consistent with a CNS inflammatory-demyelinating syndrome and fulfilled dissemination in space and time criteria for definite MS. Median age at the time of diagnosis of MS was 44.8 years (range 28.3-71.4 years). Time taken for the development of definite MS was studied by survival analysis. Cumulative event rates were; 12 months: 9%, 24 months: 15%, 36 months: 30.4%, and 60 months: 44.6%. Six of 22 patients were followed beyond 60 months. Two of these six patients developed MS later (at 66 and 112 months, respectively). Three patients remained asymptomatic despite follow-up of 10 years.

CONCLUSIONS

PATIENTS

with RAPIDD develop MS at a similar rate to treated patients (and less frequently than placebo groups) with clinically isolated syndromes from prior randomized controlled studies. Some patients with RAPIDD continue to have radiological evolution of subclinical disease without MS symptoms despite long follow-up periods.

NMO-IgG predicts the outcome of recurrent optic neuritis

OBJECTIVE

To determine the prognostic value of neuromyelitis optica (NMO)-immunoglobulin G (IgG) in patients with recurrent optic neuritis (ON). The aquaporin-4-specific serum autoantibody, NMO-IgG, is a biomarker for NMO and relapsing transverse myelitis. Recurrent ON may herald multiple sclerosis (MS) or NMO, or it may occur as an isolated syndrome. The prognosis and response to therapy differs in each of these contexts.

METHODS

We evaluated 34 patients who were tested for NMO-IgG between 2000 and 2007 and who had two or more episodes of ON without satisfying a diagnosis of MS or NMO prior to serologic testing. Clinical data were available for 25 Mayo Clinic patients (5 NMO-IgG positive and 20 NMO-IgG negative) and for an additional 9 seropositive patients whose serum was referred to the Mayo Clinic Neuroimmunology laboratory for testing.

RESULTS

Twenty percent of the patients with recurrent ON seen at Mayo Clinic were seropositive. All NMO-IgG-positive patients (vs 65% NMO-IgG-negative patients) had at least one attack with visual acuity in the affected eye worse than 20/200 (p = 0.05). In seropositive patients for whom long-term follow-up was possible (median 8.9 years after the initial ON), 6 of 12 (50%) experienced an episode of myelitis and fulfilled criteria for NMO. In contrast, 1 of 15 seronegative patients (6.7%) fulfilled McDonald criteria for MS (p = 0.03). Seropositive patients had a final visual score which was worse than that of seronegative patients (p = 0.02).

CONCLUSIONS

Neuromyelitis optica (NMO)-immunoglobulin G seropositivity predicts poor visual outcome and development of NMO. Seropositive recurrent optic neuritis is a limited form of NMO.

Demonstration of antihistamine properties with AST-1: a bioactive extract from garden slugs (Diplosolenodes occidentalis)

Parched and ground whole garden slugs are claimed in rural Jamaican folklore practices to have useful effects in the treatment of bronchial asthma. Since this claim may be associated with respiratory dysfunction due to histamine from allergic sensitization, the authors investigated the effects of a semi-pure alcoholic extract (AST-1) on histamine-induced contraction of the guinea pig in vitro tracheal muscle preparation and cutaneous allergic responses in ovalbumin sensitized guinea pigs. Chemical analysis of AST-1 by column chromatography and thin layer chromatography indicated two compounds in the composition, but the molecular structures were not determined Pharmacological evaluation of AST-1 produced a concentration-dependent inhibition of histamine-induced contraction of the guinea pig tracheal muscle preparation. AST-1 also inhibited contraction of the tracheal muscle produced by selective H1 receptor stimulation with HTMT dimaleate. H2 receptors were not involved, as indicated by the absence of contraction with dimaprit hydrochloride, a selective H2 agonist. Also, in ovalbumin sensitized guinea pigs, AST-1 and diphenhydramine, a selective H1 antagonist, inhibited the cutaneous responses due to intradermal injection of histamine and ovalbumin. These results suggest that AST-1 has H1 anti-histamine properties which can inhibit histamine-induced tracheobronchial muscle contraction and cutaneous responses due to allergy.