Angiotensin II stimulates migration of retinal microvascular pericytes: involvement of TGF-beta and PDGF-BB.

We studied the promigratory effect of angiotensin II (ANG II) on cultured bovine retinal microvascular pericytes. ANG II stimulated migration of pericytes by 86% at 10(-8) M, but this effect was lost at 10(-4) M. Migratory responses were inhibited by the ANG II type 1 (AT(1)) receptor antagonist losartan but not by PD-123319, an AT(2) antagonist.

Angiotensin II and retinal pericytes migration.

Angiotensin II (Ang II) appears to participate in the regulation of neovascularization processes in the retina. Migration of perimural cells such as pericytes plays a key role in regulation of angiogenesis. We hypothesize that Ang II stimulates migration of retina pericytes.

Comparison of blood lead levels in three groups of Sardinian children.

This paper reports blood lead levels in children from three Sardinian municipalities: Portoscuso, Iglesias, and Sestu. Portoscuso, chosen as the control area, is located about 2 km from one of the most important industrial complexes of the island. Iglesias was once an important zinc-lead mining centre.

Effects of aminopeptidase P inhibition on kinin-mediated vasodepressor responses.

We studied in anesthetized rats whether aminopeptidase P (AMP) may be involved in bradykinin (BK) metabolism and responses. For this we inhibited AMP with the specific inhibitor apstatin (Aps). Studies were done with Aps alone or together with the angiotensin-converting enzyme inhibitor lisinopril (Lis).

Activation of kininogen expression during distal nephron differentiation.

Previous studies have shown that the epithelial precursors of the connecting tubule and collecting duct express tissue kallikrein and bradykinin B2 receptors, respectively, suggesting the presence of a local kinin-producing/responsive system in the maturing distal nephron. However, evidence for the existence of kininogen in the developing nephron is still lacking. This study examined the spatiotemporal relationships between segmental nephron differentiation and the ontogeny of kininogen and kinins in the rat.

Angiotensin 1-7 induces bradykinin-mediated relaxation in porcine coronary artery.

Angiotensin 1-7 (Ang 1-7) has been reported to induce relaxation which is partially blocked by a kinin receptor antagonist. We investigated the relationship between kinins and angiotensin peptides with use of preconstricted isolated pig coronary arteries. Ang 1-7 alone (up to 10(-5) M) had no relaxant effect.

Angiotensin-(1-7) induces bradykinin-mediated hypotensive responses in anesthetized rats.

Angiotensin-(1-7) [Ang-(1-7)] reportedly potentiates hypotensive responses to bradykinin. We studied whether increases in circulating bradykinin would alter responses to Ang-(1-7). In rats anesthetized with thiobutabarbital, bradykinin infusion (5 microg/kg per minute I.

Submandibular enzymatic vasoconstrictor increases DNA and phosphoinositol synthesis by mesenchymal cells.

Submandibular enzymatic vasoconstrictor (SEV, rK9) induces vascular contraction and platelet aggregation by a mechanism requiring intact enzymatic activity. On the basis of a published report demonstrating growth-promoting enzymatic activity in an extract of the rat submandibular gland, we hypothesized that SEV would affect DNA synthesis. Recombinant SEV (rSEV), expressed in a baculovirus system, increased DNA synthesis 3- to 25-fold in Chinese hamster lung (CCL39) fibroblasts and in rabbit and rat vascular smooth muscle cells in a dose-dependent manner dose eliciting 50% of maximal response: 0.

Proteolytic activation of a putative receptor leading to vasoconstriction and platelet aggregation.

Submandibular enzymatic vasoconstrictor (SEV), a member of the kallikrein family of enzymes, elicits biological effects by a proteolytically mediated mechanism. We studied 1) whether SEV is able to aggregate platelets and 2) whether SEV may activate a receptor other than the cloned thrombin receptor. SEV (10(-8)M) aggregated platelets, released ATP and increased intracellular Ca2+.

Potentiation by aminopeptidase P of blood pressure response to bradykinin.

We examined whether a specific aminopeptidase P (APP) inhibitor, apstatin, increases vasodepressor responses to bradykinin in anaesthetized rats, and whether it would augment blood pressure responses further after treatment with the angiotensin-converting enzyme inhibitor (ACEi), lisinopril. Apstatin doubled the maximum blood pressure response to bradykinin. The area under the curve (AUC), which incorporates both peak blood pressure changes and duration of response, was doubled in apstatin-treated rats vs controls and in the apstatin+lisinopril group vs lisinopril alone.

A local kallikrein-kinin system is present in rat hearts.

It has been reported that kinins mediate part of the beneficial cardiac effects induced by treatment with angiotensin-converting enzyme inhibitors in situations such as ischemia-reperfusion injury, myocardial infarction, and cardiac hypertrophy. However, it is not known whether the heart contains an independent kallikrein-kinin system. We measured kallikrein in tissue and in the incubation medium of heart slices.

Functional analysis of conserved histidines in choline acetyltransferase by site-directed mutagenesis.

The choline acetyltransferase (ChAT) reaction involves the transfer of the acetyl group of acetyl-CoA to choline, in which an active site histidine is believed to act as a general acid/base catalyst. A comparison of the deduced amino acid sequences of the enzyme from Drosophila, pig, rat, and Caernohabditis elegans revealed three conserved histidines: Drosophila His268, His393, and His426. Each of these histidines was replaced by a leucine and a glutamine, and the kinetic properties of each of the recombinant mutant enzymes were determined.

[The relationship between dietary intake of vitamin A and risk of gastrointestinal neoplasia].

A study on dietary intake of retinol and beta-carotene was conducted in 51 patients affected by gastric (23 cases) and colorectal (28 cases) carcinoma, considering the period preceding the onset of their illness. In all patients were measured serum retinol levels. The data were compared with those in 44 control subjects.

Developmental expression of choline acetyltransferase mRNA in Drosophila.

We have measured the steady state levels of choline acetyltransferase (ChAT, EC 2.3.1.

Kinetic and inactivation studies of recombinant Drosophila choline acetyltransferase.

A cDNA for Drosophila choline acetyltransferase (ChAT) was expressed in E. coli and the recombinant enzyme partially purified. Kinetic analysis yielded the following constants for the recombinant enzyme; KmAcCoA = 29 microM, KmCoA = 25 microM, Kmcholine = 330 microM, and Kmacetylcholine = 2 mM.

Single RNA species injected in Xenopus oocyte directs the synthesis of active choline acetyltransferase.

In vitro synthesized complementary RNA (cRNA) transcribed from a non-full length Drosophila choline acetyltransferase (ChAT) cDNA clone will direct the synthesis of enzymatically active and immunologically recognizable protein when injected into Xenopus oocytes. The levels of ChAT activity expressed in injected oocytes are proportional, over 4 orders of magnitude difference, to the concentration of injected 'sense' orientation cRNA. GpppG capping of the in vitro synthesized cRNA is not necessary for expression of active ChAT but inclusion of the capping compound during in vitro transcription results in higher levels of enzyme expression at lower levels of cRNA injection.

[Effects of vitamin A (retinol), Tioadenolo and a standard diet on the plasma lipid pattern in the rat on an atherogenic diet].

The Authors have examined the action of large doses of vitamin A (2000 U.I./Kg diet) compared with that obtained by administration of a lipid lowering drug (Tioadenolo) and a standard diet in albino rats feed at first an atherogenic diet for 15 days.

Effect of a vitamin A-free diet on [3H]diazepam and [3H]GABA binding in the rat retina.

Benzodiazepine and GABA binding sites in the rat retina are influenced by a vitamin A-free diet. In rats fed a vitamin A-free diet, the total number of [3H]GABA and [3H]diazepam binding sites was markedly higher than in rats given a balanced diet. No differences were found in the apparent affinities of [3H]GABA and [3H]diazepam for their specific binding sites.