Identification of a component of rat mononuclear cell SRS as leukotriene D

Slow reacting substance (SRS), produced by rat peritoneal mononuclear cells after stimulation with ionophore A23187, consists of two main components (Bach, M.K. et al. (1979) J. Immunol. 122, 160–165). One of these components was recently identified as leukotriene C-1. The other component has now been identified as leukotriene D.     

Reproductive endocrinology of free living Pied flycatchers (Ficedula hypoleuca): prolactin and FSH secretion in relation to incubation and clutch size

Plasma levels of prolactin and FSH in free-living Pied flycatchers were studied in relation to breeding stage, clutch size and diurnal variations. In the female, the concentration of prolactin started to increase during the egg-laying and reached maximal values at the end of the incubation period. After hatching prolactin levels decreased. Male Pied flycatchers showed an increase in plasma levels of prolactin at the time when they returned to their home-territories, i.e. at the end of the incubation period. Males still occupying secondary territories at this time had low levels of prolactin. In the males, as in the females, plasma levels of prolactin decreased after hatching.
Male Pied flycatchers showed at all times higher plasma levels of FSH than did females. In both sexes FSH levels were high during the early part of the breeding season and started to decrease after the egg-laying period. After hatching time plasma levels of FSH were below the sensitivity of the assay. No differences in FSH were found between males occupying secondary territories and males in home-territories.
In incubating females FSH, but not prolactin, showed a distinct unimodal daily cycle.
No differences were found in plasma levels of prolactin and FSH between females incubating different sized clutches.     

Gene fusion vectors based on the gene for staphylococcal protein A

Two plasmid vectors, containing the gene coding for staphylococcal protein A and adapted for gene fusion, have been constructed. These vectors will allow fusion of any gene to the protein A gene, thus giving hybrid proteins which can be purified, in a one-step procedure, by IgG affinity chromatography. As an example of the practical use of such vectors, the protein A gene has been fused to the lacZ gene of Escherichia coli. E. coli strains containing such plasmids produce hybrid proteins with both IgG binding and β-galactosidase activities. The hybrid protein(s) can be immobilized on IgG-Sepharose by its protein A moiety with high efficiency without losing its enzymatic activity and they can be eluted from the column by competitive elution with pure protein A. The fused protein(s) also binds to IgG-coated microtiter wells which means that the in vivo product can be used as an enzyme conjugate in ELISA tests.     

Denture Wearers' Awareness of their Vertical Dimension

A method of analyzing facial proportions in evaluating occlusal vertical dimension was used in a test on 71 complete denture wearers aiming to find a way to rank denture wearers with different stages of reduced vertical dimension and development an instruction for patients' self judgment. By use of face drawings on a proforma the patients ranked themselves into one of four classes. The investigator also ranked the patients into these classes. There was a significant correlation (p<0.01) between the ranking by patient and investigator. The face proportions were also measured with an instrument. The distances nasion-rima oris and subnasale-gnathion were established. When ranking into classes, there was a significant (p<0.0001) correlation between the ranking by the investigator and the measurements. The results show that it may be possible to use information of facial proportions to give complete denture wearers a way of assessment of face height and thus a reason to consult a dentist in case of suspicion of reduced vertical dimension.     

Separation of basic,hydrophilic peptides by reversed-phase ion-pair chromatography: II. Analytical applications with particular reference to phosphoserine peptides

Phosphoserine peptides, obtained by phosphorylation of synthetic precursors with cyclic AMP-dependent protein kinase, can be efficiently separated from the corresponding non-phosphorylated peptides and from each other by ion-pair high-performance liquid chromatography. All experiments were performed under isocratic conditions on a C₁₈ column, using phosphate buffers with pH 3.2–4.5, n-hexane sulfonic acid as counter ion, and ethanol as organic modifier.     

A diaphragm diffusion cell applied to ethanol diffusion in agarose gel: A reproducibility study

Summary The effective diffusion coefficient of ethanol in a 4 %(w/v) agarose gel at 25°C was measured using a diaphragm diffusion cell. The reproducibility was very good; a standard deviation of only 2% was obtained. The mean value (9.5×10⁻⁶ cm²/s) agreed well with available theory and previous investigations.     

Enzyme Thermistor Analysis of Penicillin in Standard Solutions and in Fermentation Broth

Immobilized penicillinase was applied in an enzyme thermistor for calorimetric analysis of samples containing penicillin G. Standard solutions as well as extracts from fermentation broth were analyzed. The enzyme was applied bound either to porous glass or, when dealing with crude preparations, to the inner surface of nylon tubing. In the fermentation system studied, high concentrations of penicillin were present, thus allowing dilution to reduce the influence of the composition of the medium on the analysis. The useful linear concentration range was from 0.1 to 100 mM. The coefficient of correlation between analytical results obtained with the present method and those from conventional assays was 0.997.