The densities of airway binding sites for Vasoactive intestinal polypeptide (VIP) were determined using 125I-labelled VIP (IVIP) and the technique of autoradiography applied to cryostat sections. Tissue studied included: grossly normal airway tissue taken from lungs resected for bronchial carcinoma (Ca; n = 11) and lungs removed at transplant from patients with cystic fibrosis (CF; n = 7). Lung tissue obtained at post-mortem in cases of fatal asthma (n = 3) or lobes resected for bronchiectasis (n = 3) were taken as further disease controls. In the Ca controls there was dense IVIP labelling, of alveolar wall, blood vessels, airway epithelium, submucosal glands, and bronchial smooth muscle: labelling of bronchiolar smooth muscle was sparse. In comparison with the Ca controls, IVIP labelling of all tissue structures in CF, with the exception of bronchial smooth muscle, was reduced (P <0.01). The most striking reductions were associated with airway epithelium and alveolar wall. These reductions showed a similar trend in bronchiectasis but did not achieve statistical significance. There was no such change in lung tissue obtained from the cases of fatal asthma where labelling of bronchial smooth muscle and all other structures was similar to that of the Ca controls. It is likely that the reduction of VIP binding sites in CF is secondary to infection and inflammation.

Adult↗

PubMedDate not supplied

Breast reconstruction following removal of silicone implants: a new technique.

We present a new technique for breast reconstruction following removal of silicone breast implants. The technique uses locally available tissue to provide a soft and natural-appearing breast. The twin objectives of mastopexy and breast augmentation are achieved in one step. Immediate and long-term results have been very satisfactory.

Adult↗

PubMedDate not supplied

In vivo modulation of N-myristoyltransferase activity by orthovanadate.

N-Myristoyltransferase (NMT) catalyses the transfer of myristate from myristoyl-CoA to the NH2-terminal glycine residue of several proteins and are important in signal transduction. STZ-induced diabetes (an animal model for insulin-dependent diabetes mellitus, IDDM) resulted in a 2-fold increase in rat liver NMT activity as compared with control animals. In obese Zucker (fa/fa) rats (an animal model for non-insulin dependent diabetes mellitus, NIDDM) there was a approximately 4.7-fold lower liver particulate NMT activity as compared with the control lean rat livers. Administration of sodium orthovanadate to the diabetic rats normalised liver NMT activity. These results would indicate that the rat liver particulate N-myristoyltransferase activity appears to be inversely proportional to the level of plasma insulin, implicating insulin in the control of N-myristoylation.

Acyltransferases↗

PubMedDate not supplied

High molecular weight calmodulin-binding protein is phosphorylated by calmodulin-dependent protein kinase VI from bovine cardiac muscle.

A high molecular weight calmodulin-binding protein (HMW CaMBP) from bovine heart cytosolic fraction was purified to apparent homogeneity. A novel CaM-dependent protein kinase was originally discovered when the total CaM-binding protein fraction from cardiac muscle was loaded on a gel filtration column. The CaM-dependent protein kinase was shown by gel filtration chromatography to have an apparent molecular mass of 36,000 daltons. The CaM-dependent protein kinase has been highly purified by sequential chromatography on DEAE-Sepharose Cl 6B (to remove calmodulin), CaM-Sepharose 4B, phosphocellulose, Sepharose 6B gel filtration and Mono S column chromatographies. The highly purified protein kinase stoichiometrically phosphorylated the HMW CaMBP in a Ca2+/CaM-dependent manner. The phosphorylation resulted in the maximal incorporation of 1 mol of phosphate/mol of the HMW CaMBP. The distinct substrate specificity of this protein kinase indicates that it is not related to the known protein kinases (I, II, III, IV and V) that have been already characterized, therefore we would like to designate this novel kinase as a CaM-dependent protein kinase VI.

Animals↗

PubMedDate not supplied

Preliminary crystallization studies of calmodulin-dependent protein phosphatase (calcineurin) from bovine brain.

Calcineurin is a serine/threonine protein phosphatase which catalyzes the hydrolysis of both phosphoseryl/phosphothreonyl and phosphotyrosyl proteins as well as low molecular weight compounds such as p-nitrophenyl phosphate. It is a hetero-dimeric protein consisting of a 60 kDa A chain and 19 kDa B chain. Calcineurin A is organized into functionally distinct domains such as a catalytic domain, a calcineurin B binding domain, a calmodulin-binding domain, and an inhibitory domain. Calcineurin B has four EF-hand calcium binding domains with a secondary structure that is homologous to calmodulin but its metal binding properties are more similar to troponin-C. The N-terminal myristoyl group of calcineurin B might play a role in the interaction between subunits A and B during phosphorylation/dephosphorylation processes. Crystals of size 0.125 x 0.07 x 0.03 mm and 0.7 x 0.03 x 0.02 mm have been obtained for calcineurin and the A subunit respectively. Crystals of calcineurin show strong diffraction to 5.3 A and weak diffraction to 3.0 A on rotating anode operated at 50 kV and 100 mA. Further work is in progress to improve the X-ray diffraction quality of these crystals and to obtain well diffracting crystals of calcineurin B.

Animals↗

PubMedDate not supplied

Mammalian myristoyl CoA: protein N-myristoyltransferase.

Myristoyl CoA:Protein N-myristoyltransferase (NMT) is the enzyme which catalyses the covalent transfer of myristate from myristoyl CoA to the amino-terminal glycine residue of protein substrates. Although NMT is ubiquitous in eukaryotic cells, the enzyme levels and cellular distribution vary among tissues. In this article, we describe the properties of mammalian NMT(s) with reference to subcellular distribution, molecular weights, substrate specificity and the possible involvement of NMT in pathological processes. The cytosolic fraction of bovine brain contains majority of NMT activity. In contrast, rabbit colon and rat liver NMT activity was predominantly particulate. Regional differences in NMT activity have been observed in both rabbit intestine and bovine brain. Results from our laboratory along with the existing knowledge, provide evidence for the existence of tissue specific isozymes of NMT.

Acyltransferases↗