Biomedical subjects

M Soriano

Publications and source records attributed to M Soriano.

At least 37 records · Page 2Linked to original sources

PubMed1989

Effect of alpha-adrenergic blockers on calmodulin association with the nuclear matrix of rat liver cells during proliferative activation.

A transient peak of cytosolic calmodulin (CaM) was produced during the prereplicative phase of rat liver cell proliferation following partial hepatectomy. After accumulating in the cytosol, CaM apparently translocated into the nuclei, associating with the nuclear matrix. The administration of alpha 1-adrenergic blockers to hepatectomized rats prevented the association of CaM with the nuclear matrix without affecting the increase in the total nuclear CaM. The inhibitory effect of the alpha 1-antagonists was reversed by the simultaneous injection of the alpha-agonist noradrenaline. Since the activation of alpha 1-adrenergic receptors results in the release of Ca2+ from endoplasmic reticulum stores, the results suggest that the association of CaM with the nuclear matrix during proliferative activation is mediated by Ca2+ released from endoplasmic reticulum and show that the association with the matrix is independent of its intranuclear accumulation.

Adrenergic alpha-Antagonists↗

PubMed1988

New synthesis of cyclic AMP-dependent protein kinases during liver regeneration.

As has been previously reported one surge in cytosolic calmodulin is produced between 4 and 12 h after a partial hepatectomy. Moreover, a surge in cytosolic cyclic AMP and another in cyclic AMP-dependent protein kinase activity can be detected during the late period of the prereplicative phase of liver regeneration after a partial hepatectomy. It is known that these three surges are involved in triggering DNA synthesis. By kinetic studies and by injecting transcription (actinomycin D) and translation (cycloheximide) inhibitors into hepatectomized rats we have demonstrated that the cyclic AMP-dependent protein kinase surge is produced by new synthesis of the enzyme. In thyroparathyroidectomized rats subjected to a partial hepatectomy the calmodulin surge was similar to that observed in normal hepatectomized rats whereas the surge in cyclic AMP-dependent protein kinase activity was strongly decreased suggesting that the cyclic AMP-dependent protein kinase surge is not generated by the previous surge in calmodulin.

Calmodulin↗

PubMed1988

Possible cyclic AMP-dependence of the prereplicative surge of cytosolic calmodulin in proliferatively activated rat liver cells.

The infusion of a solution containing triiodothyronine, amino acids, glucagon, and heparin (TAGH solution) triggered rat liver cell proliferation. It also induced a transient prereplicative surge of cytosolic calmodulin (between 6 and 20 hr postinfusion) similar to that observed in liver cells proliferatively activated by partial hepatectomy. The injection of the beta-adrenergic blocker dl-propanolol (20 mg/kg of body weight) at the time of the infusion prevented this transient rise of cytosolic calmodulin and also inhibited the early prereplicative surge of total liver cyclic AMP, which usually occurred between 1 and 4 hr after infusion. Propanolol also inhibited the early prereplicative surge of cyclic AMP and the increase of calmodulin in liver cells proliferatively activated by partial hepatectomy. The infusion of a solution containing cyclic AMP (5 mumoles) and theophylline (10 mg) into normal rats produced an increase of cytosolic calmodulin similar to that observed after infusion of TAGH solution or after partial hepatectomy. Thus it seems that the prereplicative rise of cytosolic calmodulin observed in proliferatively activated liver cells may be regulated by the early prereplicative surge of cyclic AMP.

Animals↗

PubMed1987

Calcium transport from blood into the bile in normal and regenerating rat liver.

We have studied calcium movement from blood into the bile by injecting 45Ca2+ intravenously and measuring the radioactivity appearing in the bile. 45Ca2+ started to appear in the bile at 3 min and maximum values were observed at 5 min after its administration. The amount of calcium secreted into the bile was proportional to the blood calcium concentration indicating that the main pathway involved in calcium movement behaved as a non-saturable system. We have also studied the 45Ca2+ circulation from blood into the bile in rats subjected to a partial hepatectomy. Thereafter, the calcium transported into the bile per gram of liver increased by about 50 per cent. Since bile flow behaved in a similar way, the biliar calcium concentration remained unmodified after hepatectomy. Determination of the activities of the Ca2+ transporting systems in isolated plasma membrane fractions from regenerating livers showed no modification in these activities suggesting that the elevation in calcium movement observed after hepatectomy is not due to an increase in the circulation of Ca2+ through the transhepatocyte pathway, an observation compatible with the absence of saturation in the transport.

Animals↗

PubMed1986

Changes in sinusoidal plasma membrane enzyme activities during the pre-replicative phase of liver regeneration.

Changes in a range of plasma membrane enzyme activities during the early period of liver regeneration are thought to be related to the initiation of DNA synthesis and the triggering of cellular activation. The sinusoidal plasma membrane was isolated from control and partially hepatectomized animals at various intervals during the pre-replicative phase. The specific activities of 5'-nucleotidase, (Na+ + K+)-ATPase, Ca2+-ATPase, Mg2+-ATPase showed that after partial hepatectomy changes in the enzyme activities at the sinusoidal plasma membrane region occur. These changes are probably related to the remodeling of the cell-surface that occurs before the division of hepatocytes.

5'-Nucleotidase↗

PubMed1985

Induction of plasma membrane alkaline phosphatase in rat liver.

We have determined alkaline phosphatase activity in total liver plasma membrane fractions from rats subjected to a partial hepatectomy and sham operated with or without manipulation of the liver. In all these cases, an increase of the enzyme activity was observed. Kinetic studies of alkaline phosphatase activity performed on plasma membrane fractions from rats subjected to a partial hepatectomy suggest that alkaline phosphatase increase is produced by de novo biosynthesis of enzyme molecules. Determination of alkaline phosphatase activity in purified plasma membrane subfractions corresponding to each of the three functional regions of the hepatocyte surface (blood sinusoidal, lateral and bile canalicular), indicates that the increase of the enzyme activity observed after partial hepatectomy is selectively induced in the bile canalicular domain of the hepatocyte plasma membrane.

Alkaline Phosphatase↗

PubMed1985

Rehydration and maintenance therapy of cholera patients in Jakarta: citrate-based versus bicarbonate-based oral rehydration salt solution.

We compared the therapeutic efficacy of a World Health Organization standard bicarbonate-based oral rehydration salt solution (BBORS) with a citrate-based oral rehydration solution (CBORS) in a randomized, double-blind, controlled trial in 130 dehydrated patients with cholera aged three to 82 years. On admission the 70 patients who received CBORS and the 60 who received BBORS were similar except that the serum CO2 content (mmol/liter) was significantly lower in the CBORS group (10.8 +/- 3.6 vs. 12.5 +/- 5.3). The incidence of vomiting postadmission (41% vs. 62%, respectively), the stool output during the first 24 hr (4,252 +/- 3,900 ml vs. 6,025 +/- 4,389 ml, respectively), and the time until the patients' conditions were considered normal (38.9 +/- 14.5 hr vs. 46.3 +/- 22.7 hr, respectively) were all significantly less in the CBORS group. The serum CO2 content increased more rapidly during the first 48 hr in the CBORS group (87% +/- 74% vs. 61% +/- 68% for the BBORS group); 23% of the patients receiving CBORS and 35% of the patients receiving BBORS were considered oral-therapy treatment failures. The results indicate that CBORS was superior to BBORS for rehydration and maintenance therapy of hospitalized cholera patients in Jakarta.

Administration, Oral↗

PubMed1985

Effect of trifluoperazine on DNA synthesis during liver regeneration.

An intraperitoneal injection of the calcium-calmodulin blocker trifluoperazine into rats at 4 hr after a partial hepatectomy produced a strong inhibition of DNA synthesis observed at 24 hr after surgery; but when injection was administered at 20 hr after hepatectomy, it did not produce any effect on DNA replication. These observations indicate that trifluoperazine acted by blocking one or more events involved in triggering DNA replication but it did not affect on-going DNA synthesis. A more detailed study indicated that when trifluoperazine was injected at 4 hr after surgery, a 12 hr delay in the cytosolic calmodulin surge observed between 6 and 12 hr after partial hepatectomy (previous to initiation of DNA replication) and also in the starting of DNA synthesis was produced. These findings suggest that the pre-replicative surge of cytosolic calmodulin could be involved in triggering DNA synthesis observed after partial hepatectomy.

Animals↗

PubMed1983

Counterregulatory hormone release and glucose recovery after hypoglycemia in non-insulin-dependent diabetic patients.

An increasing number of patients with non-insulin-dependent diabetes mellitus (NIDDM) is presently being treated with insulin, some aggressively with intensified treatment schedules. However, there is little information on the ability of these patients to recover from insulin-induced hypoglycemia. We have, therefore, determined glucose recovery and counterregulatory hormone secretion in response to insulin-induced hypoglycemia in 10 NIDDM patients without autonomic neuropathy and in 6 age- and weight-matched normal controls. Recovery of plasma glucose concentration and hypoglycemia-induced increments of plasma concentrations of glucagon, epinephrine, norepinephrine, and HGH were similar in the NIDDM patients and the age- and weight-matched nondiabetic controls. It appears likely, therefore, that these NIDDM patients, if treated aggressively with insulin, may be at lesser risk for severe and prolonged hypoglycemia than insulin-dependent diabetic patients, particularly those with autonomic neuropathy or those treated with beta-adrenergic antagonists.

Adult↗

PubMed1973