Somatostatin inhibits neutrophil elastase release in vitro

The influence of the long-acting somatostatin analogue, SMS 201-995, on FMLP-induced neutrophil elastase release in vitro has been investigated. Doses from 150 ng/ml upwards inhibited elastase release, with 100% inhibition by 2500 ng/ml. Inhibition was demonstrated both by an assay measuring elastase immunometrically and by an assay based on its enzyme activity. The demonstration that SMS 201-995 inhibits protease release from polymorphonuclear leukocytes may have implications for the long-term clinical use of this somatostatin analogue.     

Changes in protein phosphorylation associated with compaction of the mouse preimplantation embryo

In order to investigate the role of protein phosphorylation in the early differentiative events of mouse preimplantation development, timed groups of embryos of various stages were incubated in medium containing [32P]orthophosphate and harvested immediately after labelling or following a chase period. The phosphoproteins obtained were separated by electrophoresis in one and two dimensions. While some of the phosphoproteins found were common to all the stages examined, the detection of many depended on both the combination of pulse-labelling and chase periods used and on the developmental stage examined. Some phosphoproteins were only found in compacted 8-cell embryos, a correlation which suggests a possible link with the post-translational mechanisms which underlie compaction.     

The sight test fee: effect on ophthalmology referrals and rate of glaucoma detection.

OBJECTIVE--To assess changes, if any, in the numbers of referrals and outcome of glaucoma referrals to the hospital eye service since the introduction of the sight test fee on 1 April 1989. DESIGN--Review of referral records and clinical notes. SETTING--Referrals to the Bristol Eye Hospital. SUBJECTS--51,919 patients referred to the Bristol Eye Hospital between 1984 and 1992. 9438 case notes of patients referred between 1987 and 1991 were examined in detail. MAIN OUTCOME MEASURES--Numbers of referrals; rate of adult true positive glaucoma referrals. RESULTS--Referrals to the Bristol Eye Hospital were between 13.7% and 19.0% fewer than expected after the introduction of the sight test fee. True positive glaucoma referrals were reduced by the same proportion. CONCLUSIONS--The numbers of patients being identified as requiring treatment or follow up for potentially blinding glaucoma have declined by nearly one fifth since the introduction of the sight test fee. An increased prevalence of preventable blindness may result.     

Intrachain disulfide bond in the core hinge region of human IgG4.

IgG is a tetrameric protein composed of two copies each of the light and heavy chains. The four-chain structure is maintained by strong noncovalent interactions between the amino-terminal half of pairs of heavy-light chains and between the carboxyl-terminal regions of the two heavy chains. In addition, interchain disulfide bonds link each heavy-light chain and also link the paired heavy chains. An engineered human IgG4 specific for human tumor necrosis factor-alpha (CDP571) is similar to human myeloma IgG4 in that it is secreted as both disulfide bonded tetramers (approximately 75% of the total amount of IgG) and as tetramers composed of nondisulfide bonded half-IgG4 (heavy chain disulfide bonded to light chain) molecules. However, when CDP571 was genetically engineered with a proline at residue 229 of the core hinge region rather than serine, CDP571 (S229P), or with an IgG1 rather than IgG4 hinge region, CDP571(gamma 1), only trace amounts of nondisulfide bonded half-IgG tetramers were observed. Trypsin digest reversephase HPLC peptide mapping studies of CDP571 and CDP571(gamma 1) with on-line electrospray ionization mass spectroscopy supplemented with Edman sequencing identified the chemical factor preventing inter-heavy chain disulfide bond formation between half-IgG molecules: the two cysteines in the IgG4 and IgG1 core hinge region (CPSCP and CPPCP, respectively) are capable of forming an intrachain disulfide bond. Conformational modeling studies on cyclic disulfide bonded CPSCP and CPPCP peptides yielded energy ranges for the low-energy conformations of 31-33 kcal/mol and 40-42 kcal/mol, respectively. In addition, higher torsion and angle bending energies were observed for the CPPCP peptide due to backbone constraints caused by the extra proline. These modeling results suggest a reason why a larger fraction of intrachain bonds are observed in IgG4 rather than IgG1 molecules: the serine in the core hinge region of IgG4 allows more hinge region flexibility than the proline of IgG1 and thus may permit formation of a stable intrachain disulfide bond more readily.     

Coloboma Hyperactive Mutant Mice Exhibit Regional and Transmitter-Specific Deficits in Neurotransmission

Abstract: The mouse mutant coloboma ( Cm /+), which exhibits profound spontaneous hyperactivity and bears a deletion mutation on chromosome 2, including the gene encoding synaptosomal protein SNAP-25, has been proposed to model aspects of attention-deficit hyperactivity disorder. Increasing evidence suggests a crucial role for SNAP-25 in the release of both classical neurotransmitters and neuropeptides. In the present study, we compared the release of specific neurotransmitters in vitro from synaptosomes and slices of selected brain regions from Cm /+ mice with that of +/+ mice. The release of dopamine (DA) and serotonin (5-HT) from striatum, and of arginine vasopressin and corticotropin-releasing factor from hypothalamus and amygdala is calcium-dependent. Glutamate release from and content in cortical synaptosomes of Cm /+ mice are greatly reduced, which might contribute to the learning deficits in these mutants. In dorsal striatum of Cm /+ mutants, but not ventral striatum, KCI-induced release of DA is completely blocked and that of 5-HT is significantly attenuated, suggesting that striatal DA and 5-HT deficiencies may be involved in hyperactivity. Further, although acetylcholine failed to induce hypothalamic corticotropin-releasing factor release from Cm /+ slices, restraint stress increased plasma corticosterone levels in Cm /+ mice to a significantly higher level than in +/+ mice, suggesting an important role for arginine vasopressin in hypothalamic-pituitary-adrenal axis activation. These results suggest that reduced SNAP-25 expression may contribute to a region-specific and neurotransmitter-specific deficiency in neurotransmitter release.     

Peptide YY (PYY) immunoreactivity is co-stored with glucagon-related immunoreactants in endocrine cells of the gut and pancreas

Summary In this study we report the localisation of PYY immunoreactivity in intestinal mucosa endocrine (EG) cells containing glucagon-related peptides and also in foetal pancreatic A cells of rat and man. Radioimmunoassay of human foetal pancreatic extracts revealed the presence of PYY immunoreactivity, the concentration of which declined with age (from 65.42 pmol/g at week 20 to 17.0 pmol at week 40; correlation coefficient=–0.893), in contrast to the amount of glucagon which remained statistically constant throughout the same foctal period. The identity of this PYY immunoreactive material with the original 36 amino acid porcine peptide has been shown by high pressure liquid chromatography (HPLC).     

Use of a biothesiometer to measure individual vibration thresholds and their variation in 519 non-diabetic subjects.

A series of 519 non-diabetic subjects had vibration thresholds at three points measured using a biothesiometer. Thresholds appeared to be log normally distributed and increased with age. Centile charts of this relation were derived from the data giving a range for normal thresholds. The biothesiometer provides a quick and reliable assessment of vibration thresholds, which when related to the centile charts gives an objective measure of the progress of diabetic peripheral neuropathy.