The influence of insulin, cAMP and the calcium ionophore X 537 A on the growth of the cartilage analagen of limb buds in vitro.

Limb buds of 11-day-old mouse embryos were cultured for 6 days with insulin, dibutyryl cAMP and X 537 A. The cartilage anlage was reduced by insulin and enlarged by dibutyryl cAMP and X 537 A. The effects are due to changes in the amount of intercellular substance.     

Absence of dopamine sensitive adenylate cyclase in the A10 region, the origin of mesolimbic dopamine neurones.

Dopamine (DA) failed to stimulate the adenylate cyclase of the mesolimbic A10 DA nerve cell body area, in contrast to tis activating effect in the nigrostriatal A9 DA cell body area. The enzyme was stimulated by GMPPNP (a GTP analog) and NaF. This indicates the absence in the A 10 cell area of DA receptors with functional coupling on adenylate cyclase, in contrast to the A9 cell area where such DA receptors are believed to be located on afferent axon terminals.     

Amphiphilic spectroscopic probes utilizing metal chelates.

The synthesis and initial applications are reported for 1-[p-(palmitamido)-phenyl]ethylenedinitrilotetraacetic acid. The results demonstrate the versatility of this spectroscopic probe molecule, which allows choice of a particular technique for a particular system as well as use of multiple spectroscopic techniques for complementary information about hydrophobic regions in biological systems.     

Octopamine levels during the moult cycle and adult development in the migratory locust, Locusta migratoria.

Octopamine content of the head of the locust Locusta migratoria has been determined during the last larval stage, moulting and adult life of 3 groups of insects: female and male gregarious, solitary and CO2 solitarized. An important difference was found between these 3 groups. Octopamine contents increased in the middle of the larval life and during the adult life. The moulting time is characterized by a sharp decrease of the octopamine content which becomes identical in the 3 groups of insects. The relation between octopamine content, hormone cycles and motility is discussed.     

An adrenergic participation subserving a positive inotropism and chonotropism of prostacyclin on isolated rat atria.

The effects of prostacyclin (PGI2) on the contractile frequency and on the isometric developed tension of spontaneously beating or paced isolated rat atria were explored. PGI2 enhanced frequency and contractile tension, both effects being blocked by the presence of propranolol, or following a pretreatment with 6-OHDopamine.     

Complexed rheumatoid factor measurements in sera, synovial fluids and in immune complex fractions.

Mild acidic treatment increases the rheumatoid factor titre of some sera and synovial fluids (SF) in rheumatoid arthritis (RA), juvenile RA (JRA) and most frequently in rheumatoid vasculitis. This unmasking of 'hidden' RF in serum and SF samples correlated with the RF-immune complexes (RF-IC) and complexed C4 present in the 3% polyethylene glycol (PEG) precipitates, indicating that by means of 'hidden' RF measurements RF-ICs are possibly detected. This method seems to provide a diagnostic tool for detecting RF-ICs in RA and other related diseases.     

Haemoglobin Bohr effect and lactic acid content of the blood of 2 water-snakes with different degrees of aquatic adaptation.

H. modestus, a water-snake with morphological respiratory adaptation to its habitat, presents haemoglobins with a lower Bohr effect than those of L. miliaris, an aquatic snake without such respiratory adaptations. The difference in blood lactic acid content of the 2 snakes submitted to mechanical stimuli appears to be compatible with the properties of their haemoglobins.     

Brain catecholamines and organ weight of mice genetically selected for high and low blood pressure.

Statistically significant differences were found between the high and low genetically selected blood pressure lines for systolic blood pressure, norepinephrine content of whole brain, absolute heart weight, heart to b. wt ratio, kidney weight, kidney to b. wt ratio, and adrenal to b. wt ratio.     

Inhibition of the NADP-linked glutamate dehydrogenase from Trypanosoma cruzi by silver nitrate.

The purified NADP-linked glutamate dehydrogenase from Trypanosoma cruzi was strongly inhibited by silver nitrate. The inhibition was reversed by reduced glutathione, and was modified by the presence of the substrates during preincubation of the enzyme with the inhibitor.