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Biomedical subjects

E Calvo

Publications and source records attributed to E Calvo.

At least 73 records · Page 4Linked to original sources
PubMed1998

Growth effects of regulatory peptides and intracellular signaling routes in human pancreatic cancer cell lines.

The intracellular events involved in normal pancreatic growth have been extensively investigated in response to cholecystokinin. Recent data indicate that tyrosine kinase, phospholipase D, phosphatidylinositol 3-kinase, and p42/p44 MAPK are stimulated in rat pancreatic acinar cells. Although we begin to understand the intracellular signaling pathways activated in normal pancreas, such information is not yet available in pancreatic cancer cells. This study was undertaken to identify the growth factors and hormones involved in cell proliferation of two human pancreatic cancer cell lines of ductal origin, the MIA PaCa-2, and PANC-1 cells, and to establish the intracellular events involved in the control of their growth. We demonstrated that FGF-2, IGF-1, cerulein, and gastrin but not FGF-1, HGF, secretin, and PACAP, stimulated proliferation of MIA PaCa-2 and PANC-1 cells. Autocrine factors such as gastrin and IGF-1 were also responsible for their proliferation. In response to EGF, FGF-2, IGF-1, cerulein, gastrin and bombesin, tyrosine kinase, and tyrosine phosphatase activities were stimulated in both cell lines. The close relationship established between cell growth and tyrosine kinase activation results from the observation that maximal growth stimulation paralleled with maximal enzyme activation and that genistein, the tyrosine kinase inhibitor, blocked cell growth and enzyme activation. The implication of PLD in growth-stimulated processes is doubtful since all growth factors and hormones tested failed to stimulate an already very active PLD activity. We finally observed a constitutive activity of p44 MAPK in both cell lines and of p42 in MIA PaCa-2 cells. However, p38 and p42 were stimulated in MIA PaCa-2 and PANC-1 cells, respectively, by all growth factors and hormones.

Animals↗
PubMed1998

Ontogeny of insulin-like growth factors (IGF), IGF binding proteins, IGF receptors, and growth hormone receptor mRNA levels in porcine pancreas.

We examined the ontogeny of mRNA levels of IGF-I and -II, IGF type 1 (IGFI-R) and type II receptors (IGFII-R), IGF binding protein-1 and -3 (IGFBP-1 and -3), GH receptor (GHR), and tissue concentrations of IGF and IGFBP in the pancreas of pigs. Tissues were collected from fetuses at 90 and 110 d of gestation and from pigs at 1, 21, 90 and 180 d of age. Northern blots were performed using total RNA hybridized with 32P-labeled cDNA probes (human IGF-I and human IGFI-R) and cRNA probes (rat IGF-II, human IGFII-R, human IGFBP-1, pig IGFBP-3, and pig GHR). There were two accelerated growth stages of the pancreas: the first one at 90 d of fetal life, which is characterized by cell hyperplasia (high ratio of DNA to body weight), and the second one at postnatal 90 d, which is attributed to cell hypertrophy (high ratios of pancreatic weight, RNA, and protein to DNA). The level of IGF-II mRNA and its tissue concentration were predominant during fetal life and low thereafter. The IGF-I mRNA level was high during fetal and early postnatal life and decreased thereafter. Messenger RNA levels of IGFI-R, IGFBP-3, and GHR and concentrations of IGFBP-1 and -2 were abundant during fetal and early postnatal life. In conclusion, IGF may be involved in various physiological periods of pancreatic development in pigs.

Aging↗
PubMed1996

Re-expression by Candida albicans germ tubes of antigens lost during subculture of blastospores.

The effect of germ tube induction on the antigenic variability in C.albicans was studied in strains from blood cultures (Group I) and superficial candidiasis (Group II). When compared by immunoblotting with a rabbit antiserum, antigenic extracts from Group I strains grown as blastospores showed a higher reactivity than that of Group II strains. Major bands in Group I strains (45-47, 33, 30 kDa) were continuously expressed through the subcultures in vitro but, with the exception of the 45 kDa band, the reactivity of all of them decreased or disappeared after the tenth subculture in Group II strains. The induction of the germ tubes produced the re-expression of the antigens lost during subculture in the yeast form, the effect being very clear in Group II strains. The re-expression by C. albicans germ tubes of antigens lost during subculture of blastospores in vitro and the higher reactivity shown by Group I strains grown in mycelial phase should be taken into consideration when a test to detect anti-C. albicans antibodies is to be developed.

Antigenic Variation↗
PubMed1996

Presence of pancreatitis-associated protein in pancreatic acinar cells of rats treated with chlorophenylalanine methyl ester.

The biological significance and function of pancreatitis-associated protein (PAP), identified in 1984 as a new secretory protein appearing during pancreatitis, remain to be elucidated. The purpose of this study was to evaluate the presence of PAP in pancreatic tissue upon its exposure to chlorophenylalanine methyl ester (CPME), a drug known to disrupt the regulated secretory pathway of acinar cells, an experimental condition that differs from acute pancreatitis. Pancreatic tissues were processed either for immunocytochemistry or for Northern blot analysis at 17-72 h after a single intraperitoneal injection of CPME in rats. Pancreatic acinar cells displayed endoplasmic reticulum intracisternal crystals consisting of an abnormal aggregation of secretory proteins as well as a sub-population of small and aberrant secretory granules. PAP mRNA was strongly increased at 17-24 h after CPME treatment, and PAP immunoreactivity was detected along the regulated secretory pathway, particularly in the small and aberrant secretory granules at these same time points. Levels of PAP and PAP mRNA decreased gradually, to become undetectable after 72 h. Autoradiographic experiments demonstrated that these small aberrant granules stored preferentially newly synthesized proteins. Our results indicate that the induction of PAP is not exclusive to acute pancreatitis since it appears in pancreatic cells as a response to certain insults and is secreted preferentially through a particular population of small aberrant granules.

Acute-Phase Proteins↗
PubMed1996

Pig pancreatic acinar cells possess predominantly the CCK-B receptor subtype.

Studies performed on pig indicated that its pancreas was insensitive to the gastrointestinal hormone cholecystokinin (CCK) and suggested that its secretions were rather under the control of the neurotransmitter acetylcholine. This study was performed to determine reasons for this insensitivity by comparing secretory responses to different secretagogues and establishing the dominant CCK receptor type. Pancreatic acini prepared from weaned piglets were evaluated for their sensitivity to carbamylcholine (Cch), caerulein, JMV-180, and secretin. RNA were extracted for CCK-A and CCK-B receptor expression using specific cRNA probes. Results indicate that pig pancreatic acini are sensitive to Cch and relatively insensitive to caerulein with no response to JMV-180, a CCKA agonist, or secretin; MK-329, a CCK-A receptor antagonist, significantly inhibited caerulein-induced enzyme secretion from 10(-8) M. The pig pancreas expresses few CCK-A mRNA receptors but a majority of CCK-B. These data demonstrate that the pig pancreas expresses a majority of CCK-B receptors. In conclusion, the pig pancreas possesses a large majority of CCK-B receptors responsible for their low sensitivity to CCK.

Amylases↗
PubMed1995

Articular aspergillosis: case report.

We present an unusual case of osteomyelitis of the tibia and septic arthritis of the knee caused by Aspergillus fumigatus in a renal transplant recipient. Although the characteristic joint involvement was present, the synovial fluid was initially sterile and contained numerous pyrophosphate crystals.

Adult↗
PubMed1992

[Spontaneous rupture of the spleen in chronic pancreatitis].

The appearing of splenic complications in the evolution of acute or chronic pancreatitis is a known fact, even though it is not that frequent. A case of splenic rupture happens during an acute bout of chronic pancreatitis. The possible pathogenic mechanisms implied are analysed as well as the forms of presentation and the approximation to diagnosis. The great difficulty in the diagnosis is determined by the scarce specificity of the clinical and biochemical manifestations. Therefore, it is called the attention upon the eventuality of this complication and the therapeutic attitudes which should be adopted.

Chronic Disease↗
PubMed1991

[Hydatid cyst of the diaphragm. Apropos of a case].

We report a case of hydatid cyst of diaphragma in a 70 year-old male, who was admitted to hospital in emergency for right basithoracic pain, aggravated by cough and deep breathing. Laboratory tests were normal. Standard roentgenographs showed a right-sided subpulmonic opacity. Pleural aspiration fluid revealed hemorrhagic pleural effusion. Lung scintigraphy showed and hypoperfused area at the base. Abdominal echography evidenced an hepatic cyst referred to the diaphragma. Thoracoabdominal CT-scans indicated a calcium-loaded mass on the postero-lateral aspect of the right lobe of liver. Surgical exploration revealed an independent hepatic cyst localized in the latero-costal bundles of the diaphragma which was removed en masse.

Aged↗
PubMed1990

Diurnal changes in actin mRNA levels and incorporation of 35S-methionine into actin in the rat hypothalamus.

1. The in vitro incorporation of 35S-methionine into actin and total soluble proteins, as well as the levels of actin mRNA, were studied in the hypothalamus and frontal cerebral cortex of adult male rats killed at six different time intervals during a 24-hr cycle. 2. The specific activity of total soluble proteins after labeled methionine incubations did not vary as a function of time of day in any of the examined brain regions. 3. The incorporation of 35S-methionine into a 43-kDa protein, corresponding to the electrophoretic mobility of actin, varied diurnally in the hypothalamus, exhibiting a maximum at 1200 hr. Such a diurnal variation was not found in frontal cerebral cortex. 4. Similar results were obtained when labeled methionine incorporation into actin was assessed in hypothalamus and cerebral cortex by an immunoprecipitation procedure. 5. An increase in actin hypothalamic mRNA levels, quantitated by dot-blot analysis, was found at 0800, 4 hr in advance to the maximum in 35S-methionine incorporation to actin. 6. The levels of actin mRNA did not vary significantly as a function of time of day in the frontal cerebral cortex.

Actins↗
PubMed1989

Haemoglobin-fortified cereal: an alternative weaning food with high iron bioavailability.

Extruded rice flour was fortified with 5 per cent bovine haemoglobin concentrate (BHC). The amino acid score of the product was 59 per cent. The protein efficiency ratio (PER) for the fortified cereal alone was 1.4; however, when given as a mixed diet of cereal and humanized milk (providing 41 and 59 per cent of the protein, respectively) PER was 2.6 (casein standard = 2.5). Iron absorption studies were performed with a double isotope technique, on 10 infants 8-10 months of age. Geometric mean absorption of the rice-BHC iron was 14.2 per cent, as measured with a tag of 55Fe-haemoglobin. The 59Fe-ferrous ascorbate reference dose had a mean absorption of 38.5 per cent. The use of a haem-iron fortified cereal as a weaning food seems feasible and advantageous, supplying an appropriate amount of absorbed iron, an adequate energy density, and a protein which could complement milk protein.

Biological Availability↗
PubMed1983

Nutritional significance of interactions between iron and food components.

Most food iron in the gut enters into two "common pools" that behave quite differently in terms of absorption. Heme iron present in hemoglobin and myoglobin, is well absorbed and is relatively unaffected by diet composition. Non-heme iron, the form of iron present in vegetables and in man's staples, generally is poorly absorbed and is greatly affected by enhancing or inhibiting substances in the diet. In experiments employing intrinsically-labeled hemoglobin as a tracer, absorption of a dry hemoglobin concentrate added to milk, a rice cereal and wheat cookies, was uniformly good, relatively constant and quite independent from the type of food. In contrast, absorption of iron salts decreases markedly when given with food. The presence or absence of inhibiting or enhancing factors of non-heme iron absorption is determinant in the possibility of obtaining required iron for most people in the world whose diet contains little heme iron. Meat and ascorbic acid are the main enhancers of non-heme food iron absorption. Common inhibitors include carbonates, oxalates, phytate, bran, tea and egg yolk. The enhancing effect of ascorbic acid on the absorption of fortification iron in milk and the effect of tea, eggs or meat on the absorption of bread iron from common Chilean meals are discussed as examples of interactions of food components with non-heme iron.

Ascorbic Acid↗