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T Morales

Publications and source records attributed to T Morales.

At least 19 recordsLinked to original sources
PubMed2003

Brainstem prolactin-releasing peptide neurons are sensitive to stress and lactation.

Prolactin-releasing peptide (PrRP) was originally thought to participate in the control of adenohypophyseal prolactin secretion, but its predominant expression in a subset of medullary noradrenergic neurons is more in line with roles in interoceptive and/or somatosensory information processing. To better define functional contexts for this peptide system, immuno- and hybridization histochemical methods were used to monitor the capacity of PrRP neurons to display activational responses to lactation, suckling, acute footshock or hypotensive hemorrhage. PrRP mRNA signal was reduced in the medulla of lactating dams, relative to both male and diestrus female controls, with cell counts revealing 42% and 43% reductions in the number of positively hybridized cells in the nucleus of the solitary tract (NTS) and ventrolateral medulla, respectively. Lactating mothers killed after a 90 min suckling episode (following 4 h pup removal) failed to show induced Fos expression in identified medullary PrRP neurons, despite the fact that responsive neurons were detected in other aspects of the caudal NTS. By contrast, acute exposure to hypotensive (25%) hemorrhage or footshock each activated substantial complements of medullary neurons expressing PrRP mRNA. A substantially greater fraction of the total medullary PrRP population exhibited sensitivity to footshock than hemorrhage (71 versus 39%, respectively). These results suggest that medullary PrRP neurons are negatively regulated by (presumably hormonal) changes in lactation, and are not recruited to activation by suckling stimuli. These populations exhibit differential sensitivity to distinct acute stressors, and may participate in the modulation of adaptive neuroendocrine and autonomic responses to each.

Animals↗
PubMed2003

Inflammatory C2-3 subluxation: a Grisel's syndrome variant.

The concurrence of non-traumatic atlanto-axial subluxation with inflammation of the adjacent neck tissues is known as Grisel's syndrome. We report a 5 year old boy with recurring episodes of head tilt and painful and restricted neck movements that developed after repeated bouts of sinusitis. Radiographs showed a subluxation of the C2-3 joint. Medical treatment, with cervical collar, physiotherapy, and non-steroid anti-inflammatory agents, led to complete cure of the disease. We suggest that Grisel's syndrome can occur in a location different from the classic atlanto-axial joint. To the best of our knowledge, this is the first report of a symptomatic case of Grisel's syndrome occurring at the C2-3 segment.

Atlanto-Axial Joint↗
PubMed2001

Recombinant canine IL-13 receptor alpha2-Fc fusion protein inhibits canine allergen-specific-IgE production in vitro by peripheral blood mononuclear cells from allergic dogs.

Human IL-13, like IL-4, is involved in the regulation of B-cell development, IgE synthesis and allergic responses. However, because IL-13 does not affect either murine Ig class switching or IgE production in vitro, the use of murine models to study the role of IL-13 in IgE-mediated diseases has been limited. In this communication, we report that recombinant protein of canine IL-13 (rcaIL-13) stimulates production of allergen-specific-IgE in vitro by peripheral blood mononuclear cells (PBMC) from flea allergen-sensitized dogs, and that this stimulation activity is specifically inhibited by recombinant protein of canine IL-13Ralpha2 and Fc fragment of canine IgG heavy chain (rcaIL-13Ralpha2-Fc). The data suggest that the regulatory effects of IL-13 on IgE production in canine PBMC are similar to those reported in humans. Thus, canine IL-13 may be a central mediator of allergic diseases in dogs, and allergic dogs may be excellent models for research on IgE-mediated diseases in humans.

Amino Acid Sequence↗
PubMed2000

Prolactin-releasing peptide is expressed in afferents to the endocrine hypothalamus, but not in neurosecretory neurones.

Prolactin release from the anterior pituitary is regulated principally by inhibitory influences imparted by the tuberoinfundibular dopamine system. Stimulatory control is provided by several hypothalamic, peripheral and local factors. Recently a new peptide, prolactin releasing peptide (PrRP), showing prolactin-secretagogue effects was discovered, synthesized and found to be expressed in brain. We have used histochemical and axonal transport methods to characterize the distribution of PrRP mRNA in the rat brain, and to identify possible pathways through which this factor might be delivered to the anterior lobe of the pituitary and thereby participate in the regulation of prolactin secretion. Analysis of histochemical preparations indicated that apart from a small population of cells in a non-neurosecretory portion of the hypothalamus, PrRP mRNA is expressed exclusively in the caudal part of the nucleus of the solitary tract and in the caudal ventrolateral medulla. All medullary PrRP expressing cells could be immunolabeled for tyrosine hydroxylase, and none were found to stain for glucagon-like peptide-1, identifying them as comprising subsets of A2 and A1 noradrenergic neurones, respectively. Numerous PrRP-expressing cells were retrogradely labelled following tracer injections in the paraventricular nucleus, while only a handful were backfilled following intravenous injections of tracer, indicating that this population issues substantial projections to the endocrine hypothalamus and meager ones to the median eminence and/or posterior pituitary. This conclusion was supported by the results of experiments in which the anterograde tracer, biotinylated dextran-amine, was injected into the PrRP cell group in the nucleus of the solitary tract. These findings suggest that PrRP expressing neurones display a highly restricted distribution, and are in a position to regulate the output of particular cell types in the endocrine hypothalamus. Whether and how PrRP might be delivered to the anterior pituitary remains to be determined.

Amidines↗
PubMed2000

Relative risk of dysplasia for patients with intestinal metaplasia in the distal oesophagus and in the gastric cardia.

BACKGROUND: Biopsy specimens obtained from the gastro-oesophageal junction can reveal intestinal metaplasia in patients presenting for routine upper endoscopy. The site of biopsy may play a critical role in determining the dysplasia risk of a patient. AIMS: To evaluate prospectively the dysplasia risk in patients with intestinal metaplasia of the distal oesophagus or within the gastric cardia. METHODS: Patients with short segment Barrett's oesophagus (SSBO) and cardia intestinal metaplasia (CIM) were followed prospectively. RESULTS: 177 patients with SSBO were identified (mean age 62 years, range 38-82; 91% whites). Twenty prevalence cases of dysplasia in SSBO were detected: 17 low grade dysplasia (LGD), three high grade dysplasia (HGD). Seventy six patients with CIM were identified (mean age 67 years, range 37-81; 81% whites). A single prevalence case of LGD in CIM was detected. During follow up of 78 SSBO and 34 CIM patients, dysplasia developed in nine (seven LGD, two HGD) with SSBO and in one (LGD) with CIM. There were significant differences between the two groups with respect to age, ethnicity, dysplasia prevalence, and incidence. Time to dysplasia progression was significantly longer in CIM compared with SSBO patients. Of the five patients with SSBO and HGD, one developed adenocarcinoma of the oesophagus on follow up. No HGD or cancers have been detected over this time period in CIM patients. CONCLUSIONS: The dysplasia risk is significantly greater in SSBO than in CIM patients, indicating two potentially different clinical processes. Future studies should separate SSBO from CIM in order to enhance the understanding of the pathophysiology and malignant potential of each entity.

Adenocarcinoma↗
PubMed2000

[Antimicrobial activity of organic extracts isolated from Aplysina fistularis (Demospongiae: Aplysinidae)].

Organic extracts of the sponge Aplysina fistularis (Pallas 1766) were tested for antimicrobial activity against Gram positive bacteria (Staphylococcus aureus) and Gram negative bacteria (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa). The minimal inhibitory concentration (MIC) and toxic activity of extract were determined. Susceptibility trials of organic fractions obtained by VLC: Hexane, EtOAc and CHCl3 showed that EtOAc fraction has antibacterial activity against E. coli, while CHCl3 fraction inhibited E. coli and S. aureus growth. The later refractioning of EtOAc fraction and the biodirected assays showed that fractions F12 and F13 of EtOAc/Hex and EtOAc F14 were bioactive against Gram positive and Gram negative bacteria. Only EtOAc/MeOH Sf2 from subfractionig of EtOAc F14 produced inhibition for E. coli and S. aureus. In Sf2 EtOAc/MeOH, MIC was moderate for S. aureus (MIC > 256 g/ml). F4 CHCl3/MeOH produced a high inhibition in S. aureus (MIC = 0.125 g/ml) and for E. coli (MIC > 16 g/ml). F10 CHCl3/MeOH showed a moderate activity against S. aureus (MIC > 128 g/ml) and low activity against E. coli (MIC = 512 g/ml). F10 CHCL3/MeOH did no present toxic activity against Artemia salina. The fractiorts F4 CHCL3/MeOH and Sf2 EtOAc/MeOH were toxic for this organism when the concentration was higher than 100 microg/ml. LC50 in both cases was 548.4 and 243.4 microg/ml respectively. Secondary metabolites of medium polarity obtained from A. fistularis have a wide spectrum of anti bacterial activity. Toxicity analysis suggests that only F10 CHCL3/MeOH has potential as an antimicrobial agent for clinical use.

Animals↗
PubMed1998

An ERp60-like protein from the filarial parasite Dirofilaria immitis has both transglutaminase and protein disulfide isomerase activity.

Transglutaminases (TGases; EC 2.3.2.13) are a family of enzymes that catalyze calcium-dependent covalent cross-linking of cellular proteins by establishing epsilon-(gamma-glutamyl)lysine isopeptide bonds. These covalent isopeptide bonds are of great physiological significance because they are highly resistant to proteolysis, denaturants, and reducing agents. Prior studies have demonstrated the presence of isopeptide bonds in the sheath and cuticle of filarial parasites, suggesting an important role for TGase-catalyzed reactions during the growth and development of filarial nematodes. Herein we report the identification and cloning of a cDNA encoding a TGase from the dog heartworm Dirofilaria immitis (DiTG). The DiTG expressed in Escherichia coli (recombinant DiTG) was able to catalyze calcium-dependent cross-linking reactions. The derived amino acid sequence of the DiTG cDNA (pDiTG) predicts a protein of 57.1 kDa and includes an N-terminal hydrophobic signal peptide. The pDiTG has no sequence similarity with any of the known TGases, but it has significant homology to protein disulfide isomerase (PDI) and, particularly, to the PDI-related endoplasmic reticulum protein ERp60, a PDI isoform found in the lumen of endoplasmic reticulum. As predicted from the amino acid sequence homology, recombinant DiTG catalyzed the isomerization of intramolecular disulfide/sulfhydryl bonds in denatured RNase in vitro as effectively as did mammalian PDI. Conversely, purified PDI from bovine liver could catalyze protein cross-linking reactions in a Ca(2+)-dependent manner. This report describes the dual catalytic activity of TGase and PDI in post- and/or cotranslational modification of newly synthesized proteins. These TGase-catalyzed posttranslational modifications may play a pivotal role in the synthesis of new cuticle during the growth and maturation of filarial parasites.

Amino Acid Sequence↗
PubMed1994

Adaptive response induced by mitomycin C measuring the frequency of SCEs in human lymphocyte cultures.

The induction of an adaptive response was obtained using mitomycin C (MMC) as both stimulating and challenging agent. Human lymphocyte cultures of two female donors were treated with 5, 10 and 20 ng/ml of MMC as conditioning doses. For the challenging treatments two different protocols were used (200 ng/ml for 4 h, and 400 ng/ml for 1 h). The scoring of sister chromatid exchanges (SCE) in the first challenging combination showed the following inhibition related with the expected SCE damage: 49.2%, 51.4%, and 36.9% for one donor, and 42.0%, 38.6%, and 34.7% for the other (corresponding to the stimulating dosages 5, 10, and 20 ng/ml, respectively). The second challenging combination gave an inhibition of 53.8%, 40.5% and 30.2% in one donor and 43.2%, 45.9% and 30.3% in the other donor.

Adaptation, Physiological↗
PubMed1991

[Feeding of healthy premature infants with milk of their own mothers].

An experience of feeding healthy premature infants (< 1,800 g) on their mother's milk is communicated. Feeding starts at an early time (15 hours); achieving maximum volumes at the 12th day. Loss of weight is 10% less than the birth weight and recovery occurs at the 12th day. In this way, a postnatal speed growth of 26 g/day can be obtained; which is similar than that observed during the third of the pregnancy. 75% of the calories provided to more of the 66% of the infants attended by our Unity, is based on their own mother's milk at the time of discharge.

Female↗
PubMed1967

The electrical and mechanical activity of the esophageal cell of Ascaris lumbricoides.

The esophagus of Ascaris is a syncytial muscle organ of tubular shape in which the myofibrils are arranged radially between the lumen and the external surface. A resting potential of almost 40 mv (cytoplasm negative) is maintained by the extracellular organic anions (volatile fatty acids) found in the perienteric fluid. Replacement of these anions by Cl- ions results in a large depolarization. The resting potential is also decreased when the external pH is lowered. The leading phase of the action potential with a positive overshoot of about 18 mv elicits contraction of the myofibrils, development of negative pressure within the lumen, and suction of liquid and food particles. The mechanical energy stored in the elastic components of the cell is released when the myofibrils relax, thus injecting the contents of the lumen into the intestine. A fast and synchronous relaxation is elicited by a regenerative membrane polarization, a negative spike with a peak value of up to 108 mv produced by an increase in the permeability of the membrane to K+ ions. Cells completely depolarized in "chloride" saline are still able to generate such large potassium spikes.

Action Potentials↗
PubMed1967

Extracellular action potentials recorded from the interior of the giant esophageal cell of Ascaris.

Exploration of the cytoplasm of the giant esophageal cell of Ascaris with a recording microelectrode shows the existence of shallow spaces where the microelectrode tip becomes extracellular in spite of being in the interior of the cell. When the microelectrode penetrates into these spaces from the cytoplasm, the resting potential shifts to a different level or entirely disappears. At the same time the large intracellular spikes are replaced by small transients similar to extracellularly recorded action potentials. It is concluded that such spaces are in communication with the external solution, and separated from the cytoplasm by an electrically active membrane; i.e., able to generate action potentials. Measurement of the potential differences between the interior of the spaces and the external solution shows that although some are not polarized, many spaces have a resting potential of the same polarity as that of the cytoplasm. It is suggested that although they are of larger size these spaces may be equivalent to the tubular systems which in other muscle cells are known to be involved in the spread of excitation into the cytoplasm.

Action Potentials↗