Mechanism of binding of soluble immune complexes to lymphocytes

Soluble immune complexes prepared with either (a) ¹²⁵I BSA and mouse antiserum to BSA in the presence of fresh mouse serum (AgAbC) or with (b) ¹²⁵I BSA and a 7S fraction of the mouse antiserum to BSA (AgAb) bind to a certain proportion of mouse lymph node and spleen lymphocytes (but not to thymocytes). The efficiency of binding is greater when complexes are prepared at defined antigen/antibody ratios and when the incubation with lymphocytes is performed at 37 °C. However, a significant degree of binding occurs at lower temperatures and even at 0 °C. Cells which bind soluble complexes overlap extensively with complement receptor lymphocytes (CRL) (B lymphocytes) since the specific elimination of CRL also depletes the population of cells which can bind soluble complexes. Two types of interactions are involved in the binding: one mediated by antibody which has been aggregated by antigen and another by complement (probably C3). They can be operationally distinguished because (1) after treatment of the lymphocytes with trypsin, the binding of AgAbC (but not of AgAb) is strongly inhibited; (2) the binding of AgAb (but not of AgAbC) is inhibited by heat-aggregated Ig; (3) the binding of AgAbC (but not of AgAb) to lymphocytes inhibits their subsequent interaction and rosette formation with erythrocytes sensitized by antibody and complement components; and (4) cobra venom factor markedly alters the binding of AgAbC to lymphocytes.     

Brain Fog in Hypothyroidism: Understanding the Patient’s Perspective

ObjectivePatient-centered studies have shown that several patients on thyroid hormone replacement therapy for hypothyroidism exhibit persistent symptoms, including “brain fog.” Here, we aimed to determine which of these specific symptoms are associated with brain fog, identify patient-reported factors that modify these symptoms, and identify patient concerns related to brain fog not included in thyroid-specific questionnaires.MethodsA survey on brain fog symptoms adapted from thyroid-specific patient-reported outcome was distributed online. Textual data analysis was performed to identify common areas of concern from open-ended survey responses.ResultsA total of 5170 participants reporting brain fog while being treated for hypothyroidism were included in the analysis. Of these, 2409 (46.6%) participants reported symptom onset prior to the diagnosis of hypothyroidism, and 4096 (79.2%) participants experienced brain fog symptoms frequently. Of the symptoms listed, participants associated fatigue and forgetfulness most frequently with brain fog. More rest was the most common factor provided for improving symptoms. The textual data analysis identified areas of concern that are not often included in thyroid-specific quality of life questionnaires, including a focus on the diagnosis of hypothyroidism, the types and doses of medications, and the patient-doctor relationship.ConclusionBrain fog in patients treated for hypothyroidism was associated most frequently with fatigue and cognitive symptoms. Several additional areas of patient concern were found to be associated with brain fog, which are not typically addressed in thyroid-specific questionnaires.     

Persistence of chromosomal lesions induced in actively proliferating bone marrow cells of the mouse.

The persistence of chromosomal lesions induced in vivo by mitomycin C (MMC) was evaluated by cytogenetic analysis of mouse bone marrow cells. Chromosome aberration (CA) and micronucleus (MN) frequencies were estimated at different times after treatment, up to 42 days. The frequency of CA per cell decreased in the first 3 days after treatment, but a secondary peak appeared on the 4th day, followed by a stabilization around 0.03 CA per cell (significantly different from the control value), which persisted up to 17 days. At the next time intervals tested (28 and 42 days), the CA frequency returned to the control level. In disagreement with these data obtained directly on metaphases, the MN frequency, as evaluated in polychromatic erythrocytes, decreased quickly after treatment, reaching the control value on the 5th day. We attempted to enhance the sensitivity of the MN test by using CREST antibodies and indirect immunofluorescence. However, higher proportions of CREST- MN in treated than in control animals were observed only at short time intervals, confirming the results obtained with the conventional MN assay.     

Comparative studies of monohemic bacterial C-type cytochromes. Redox and optical properties of Desulfovibrio desulfuricans Norway cytochrome C553(550) and Pseudomonas aeruginosa cytochrome C551

Redox properties of cytochrome c553(550) from Desulfovibrio desulfuricans Norway (Eo' = 0.04 + 0.02 V/NHE) and cytochrome c551 from P. aeruginosa (Eo = 0.25 +/- 0.02 V/NHE) are compared with those of some monohemic c-type cytochromes. The pK value for the equilibrium between the pH-dependent forms of cytochrome c553(550) (pK = 10.3 +/- 0.1) has been also determined. It is to be noted that the difference between redox potentials can extend to nearly 250 mV, though the axial heme ligands are identical. Structural reasons have to be invoked to explain these variations.     

De novo ABA synthesis and expression of seed dormancy in a gymnosperm: Pseudotsuga menziesii

Seeds of dormant Douglas-fir seeds germinated poorly when they were cultivated at 20–23 °C while isolated embryos germinated fully within two weeks. Seed dormancy was therefore imposed on the embryo by its surrounding structures. This physiological behaviour was well correlated with changes in ABA level during culture. Indeed, the ABA level decreased in isolated embryos while it increased in both embryo and megagametophyte during culture of whole seeds. The origin of this increase was analysed and the different ways by which seed coats could interfere with ABA accumulation are discussed.