Insulin-dependent diabetes, an autoimmune disease

In type I (insulin-dependent) diabetes evidence for an autoimmune process is now fully established. This is also true for a similar disease observed in the NOD mouse and the BB rat. In addition to circulating antipancreatic antibodies, we demonstrated T-lymphocyte mediated cellular immunity in both these diabetic animals and in the human. Immunological abnormalities precede the development of diabetes and may be responsible for beta cell alteration. Evidence for this interpretation appears stronger for cell-mediated than for humoral immunity. However, full demonstration and understanding of the relationship between anti-beta cell immunity and beta cell alteration still raise many unresolved problems.     

Bryologische Fragmente

Ohne Zusammenfassung     

Attempt to detect recombination between B-F and B-L genes within the chicken B complex by serological typing,in vitro MLR,and RFLP analyses

In search for recombinants within the chicken major histocompatibility B complex, 1155 animals from crosses between the congenic lines CB (B¹²) and CC (B⁴) were tested with alloantibodies and monoclonal antibodies for the B-F (class I), B-L (class II), and B-G (class IV) antigens and by mixed lymphocyte reaction. The absence of detectable recombination was confirmed by restriction fragment length polymorphism analysis with B-L and B-F probes. Together with previous reports, this indicates that the distance between the B-F and B-L loci is below 0.01 centimorgan.     

Physiological control and process kinetics of clavine alkaloid production byClaviceps purpurea

Summary Kinetic parameters of production of clavine alkaloids were evaluated in twoClaviceps purpurea strains. Mutagenesis brought about enhanced resistance of the biosynthetic system towards alkaloids. Addition of glucose into the fermentation medium altered the zero order kinetics of production to activation-inhibition kinetics. The glucose treatment allowed performance of both elymoclavine-inhibitionless and clavine alkaloid-decompositionless fermentations if a combination of fermentation and separation units in a closed loop was used.Nomenlacture k ₁ rate constant of agroclavine synthesis (mg Agro · mg Elymo/l·g DW·day for stage 1, mg Agro/g DW·day for stage 2) - k ₂ parameter describing inhibition of agroclavine formation rate by elymoclavine (mg Elymo/l) - k ₃ specific rate of agroclavine decay (l/g DW·day) - k ₄ maximal specific rate of elymoclavine synthesis (stage 1, 1/g DW·day, stage 2, mg Elymo/g DW·day) - k ₄ ^– maximal specific rate of elymoclavine synthesis in stage 1 (inhibition-activation mechanism) (mg Elymo/g DW·day) - k ₅ physiological constant describing the elymoclavine decay rate (l²/g DW·day·mg Elymo) - k ₅ ^– physiological constant describing the activation of elymoclavine biosynthesis by elymoclavine (mg Elymo/l) - k ₆ physiological constant describing the repression of elymoclavine biosynthesis by elymoclavine (mg Elymo/l) - k ₇ maximal specific growth rate (1/day) - k ₈ specific rate of biomass decay (l/g DW·day) - A agroclavine concentration (mg/l) - E elymoclavine concentration (mg/l) - r _A specific rate of agroclavine biosynthesis (mg Agro/g DW·day) - r _E specific rate of elymoclavine biosynthesis (mg Elymo/g DW·day) - r _i specific rate of alkaloid biosynthesis (mg alkaloid/g DW·day) - X dry biomass concentration (g/l) - specific growth rate (1/day) Abbreviations Agro agroclavine - Elymo elymoclavine - Chano chanoclavine - DW dry weight of biomass     

Voluntary progression order in captive rhesus macaques

The sequence in which 14 laboratory rhesus macaques left their home enclosure during a routine catching procedure was recorded on 30 occasions during 6 weeks. The animals were trained to voluntarily exit one by one and enter a transport cage for weighing and/or treatment. Mean weekly exit orders cross-correlated significantly, and individuals retained their exit positions with remarkable consistency throughout the study period. An animal's position did not depend on its sex, age, or dominance rank. The oldest female never failed to enter the transport cage as number 1. When she was prevented from taking the lead, the group was hesitant but eventually proceeded in the usual order. Food was a strong, yet not absolute, incentive for the monkeys to cooperate. If they could not expect a reward, they took more time before proceeding, but did so in the habitual order. The predictability of the exit sequence has practical managerial value because it makes it possible for a single person to quickly catch a selected group member when necessary.     

Immunohistochemical localization of porcine diazepam-binding inhibitor (DBI) to rat endocrine pancreas

Summary The occurrence of diazepam-binding inhibitor (DBI), isolated and characterized from porcine upper intestine, was examined in the pancreas of Sprague-Dawley albino rats using indirect immunofluorescence. The polypeptide was found in the endocrine Langerhans islets and, utilizing double-labelling controls, it was shown to be present within the peripherally located glucagon-containing cells. Regulation of islet hormone production may therefore be under DBI control.     

Glycopeptides in soluble egg antigen of Schistosoma mansoni: isolation, characterization, and elucidation of their immunochemical and immunopathological relation to the major egg glycoprotein (MEG)

The major egg glycoprotein (MEG) of Schistosoma mansoni was purified by ion-exchange chromatography of glycoprotein fraction obtained from soluble egg antigen (SEA) by lectin affinity chromatography. Small carbohydrate-rich fragments (CRF) contained in the glycoprotein fraction of SEA were isolated by ultrafiltration followed by dialysis (10 to 13 kd). Comparison of MEG and CRF yielded the following results: purified MEG (70 kd) contains about 77% carbohydrate, and CRF contains 92.5% carbohydrate. When radioiodinated and run by SDS-PAGE, each yielded a single band with respective Rf values of around 0.33 and 1.0 CRF is capable of inhibiting, in a Farr-type RIA, the binding of 125I-MEG to serum from chronically infected mice. Furthermore, CRF and MEG exhibit a single and continuous line of radioimmunodiffusion. CRF, unlike SEA, SEA glycoproteins, or purified MEG, is incapable of eliciting delayed footpad swelling in egg-sensitized mice or of inducing granulomatous hypersensitivity, when given at amounts equivalent to or higher than MEG by protein or carbohydrate content. Thus, whereas SEA, SEA glycoproteins, or MEG elicited in a representative test net swelling of 0.28 mm, 0.34 mm, and 0.29 mm, respectively, CRF gave net swellings of 0.06 mm, similar to the control value (0.07 mm) in unsensitized mice. Also, mice sensitized to viable eggs, SEA, or purified MEG exhibited, after i.v. challenge with viable eggs, a mean area of granulomas in the lungs of 12,389 micron2, 16,412 micron2, and 12,354 micron2, respectively, as compared with 7940 micron2 in CRF-sensitized mice and 8428 micron2 in unsensitized control mice. Thus, CRF appears to contain fragments of MEG that are serologically active but immunopathologically inactive at the concentrations used.     

Schistosoma mansoni: radiometric assay of lectin binding specificities of the major egg glycoprotein and its carbohydrate-rich fragment

The binding by lectins of the Schistosoma mansoni major egg glycoprotein and of a carbohydrate-rich fragment which is serologically cross-reactive with it was studied. The major egg glycoprotein was purified from a crude soluble egg antigen by a succession of affinity chromatography procedures on concanavalin A-sepharose and by ion-exchange chromatography. The carbohydrate-rich fragment was isolated by ultrafiltration of the crude glycoprotein fraction initially obtained from the crude soluble egg antigens. The major egg glycoprotein and the carbohydrate-rich fragment contain 77 and 92.5% carbohydrate, respectively. When radioiodinated and run on SDS-polyacrylamide gel electrophoresis, each of them exhibited a single peak with respective Rf values of 0.33 and 1.0, and their respective molecular weights were 70K and 10-13K. The binding of the radioiodinated major egg glycoprotein and the carbohydrate-rich fragment by peanut agglutinin, Ricinus communis agglutinin-60, wheat germ agglutinin, and lotus agglutinin was studied by double diffusion in agar, and by a radiometric solid-phase assay in which the lectins were used to coat microtiter plates. The latter assay was employed to determine the specificity of the binding by inhibition with the specific sugars. Both the major egg glycoprotein and the carbohydrate-rich fragment bound specifically to concanavalin A columns as indicated by their isolation procedure. They also bound specifically to peanut agglutinin, R. communis agglutinin 60, and lotus agglutinin, while binding by wheat germ agglutinin appeared not to be specific.(ABSTRACT TRUNCATED AT 250 WORDS)     

Courtship behavior among musk-ox males kept in confinement

During twelve 2-h observation sessions courtship behavior was recorded among seven musk-ox males (Ovibos moschatus) kept in a paddock together with six females. The animals were sexually mature and of the same age. Foreleg kicking and genital sniffing were more common than mounting. All three activities were of a nonaggressive nature but were shown almost exclusively by dominants toward subordinate partners. Assuming the role of courted females, recipients were never the target of aggressive acts. It was concluded that courtship among mature musk-ox males functions as a nonaggressive reinforcement of dominance, promoting low-risk coexistence of males.