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J L Arias

Publications and source records attributed to J L Arias.

84 records · Page 5Linked to original sources
PubMed1981

Effect of prostaglandin F2 alpha on the bovine fetal ruminal wall in vitro.

Strips of rumen wall from bovine fetuses were incubated in an organ bath with prostaglandin F2 alpha (0.13 to 33.76 microgram/ml). The highest reactivity with a submaximal dose (17.03 microgram/ml) was observed in the period between 3.0 and 7.9 months of fetal age. A smaller response, but higher than in 1.0 to 2.9 months old fetuses, was observed in the 8.0 to 8.9 months fetuses. The period of the highest reactivity to prostaglandin F2 alpha coincides with the age of onset of papillary morphogenesis and the period of highest reactivity to autonomic and putative transmitter drugs.

Animals↗
PubMed1980

Glycogen in the epithelium of the bovine fetal rumen.

Electron-microscopic observation of bovine fetal rumen reveals that the distribution and structure of glycogen are modified during fetal development. Both basal and superficial cells increase their glycogen content in fetuses up to 6 months of age. In older fetuses, the epithelial glycogen content diminishes. These morphological changes resemble the perinatal metabolic changes occurring in other organs.

Animals↗
PubMed1980

Observations on the histogenesis of bovine ruminal papillae.

Changes in numbers of epithelial and connective tissue cells, thickness of connective tissue, and height and diameter of papillae were quantitated in fetal and postnatal bovine ruminal mucosa. During fetal development, the height of papillae and number of fibroblasts increased, the diameter of papillary base and thickness of subpapillary and interpapillary connective tissue remained constant, and the numbers of basal and superficial cells of the epithelium decreased. During the first 2 months of postnatal development, the height of papillae and numbers of fibroblasts enclosed in the papillary core decreased, and the diameter of the papillary base and the interpapillary distance increased. In consequence, the increase in connective tissue, rather than its redistribution, was involved in papillary development. The epithelial reorganization appeared to follow the changes occurring in the connective tissue, at least during fetal development.

Animals↗
PubMed1979

Distribution and nature of desmosomes in the bovine developing ruminal epithelium.

Desmosomes entirely similar to those of the deeper layers of ruminal epithelium are seen in the luminal layers of the early fetal ruminal epithelium. In the older fetuses, these desmosomes have morphological features that reveal to some extent the occurrence of processes of keratinization. This could indicate that the basis for cell keratinization is already present in the fetus and that postnatal keratinization corresponds mainly to the full development of the prenatally existing pattern of differentiation.

Animals↗
PubMedDate not supplied

Chronic portal hypertension in the rat by triple-portal stenosing ligation.

A surgical technique based on the development of a triple stenosing ligation is used to worsen the complications inherent to the prehepatic chronic portal hypertension. The results have been compared with those obtained in rats with a single-portal stenosing ligation. An increase (p <.05) in the body, liver, spleen, and kidney weights as well as a decrease (p <.001) in the testes weight to body weight ratio were produced in both groups of animals. In addition, the variability in the obtained weights, particularly in the liver weight, stands out. The incidence of portosystemic and portohepatic collateral circulation and of the mesenteric venous vasculopathy increases in the animals with triple-portal stenosing ligation. The new proposed technique is a valid alternative to the classic one that used single portal stenosing ligation.

Animals↗
PubMedDate not supplied

Microsurgical extrahepatic cholestasis in the rat: a long-term study.

An experimental model of microsurgical cholestasis is studied as an alternative to the most frequently used surgical techniques, based on the section of the common bile duct. This microsurgical technique consists of the resection of the extrahepatic biliary tract, that is, of the common bile duct in continuity with the bile ducts that drain the four lobes of the rat liver. At 30 days of evolution, rats with microsurgical cholestasis do not develop biliary pseudocysts or intraperitoneal hilar hepatopulmonary abscesses and show an increase (p < 0.001) in total bilirubin (9.50 +/- 1.50 mg/dL vs. 1.60 +/- 0.35 mg/dL), bile acids (225 +/- 87 micromol/L vs. 12.5 +/- 14.50 micromol/L), gamma-glutamyltranspeptidase (375 +/- 143 U/L vs. 8 +/- 11 U/L), and alkaline phosphatase (73 +/- 25 U/L vs. 23 +/- 4 U/L) levels. The histological study shows fibrosis with biliary proliferation. The microsurgical cholestasis technique is a valid alternative to other techniques and can be an adequate experimental model for the study of etiopathogenic mechanisms of obstructive jaundice and especially to study extrahepatic biliary atresia.

Animals↗
PubMedDate not supplied

[Spinal cord infarctions as a complication of coronary angiography].

INTRODUCTION: Spinal cord infarction is the commonest vascular disorder of the spinal cord, but its incidence is low and difficulty in diagnosis means that often it is not recognized. Although cases of spinal cord infarction have been reported as complicating angiographic procedures, it rarely occurs nowadays. CLINICAL CASE: We describe a case of spinal cord infarction following coronariography. The patient was a 61 year-old man with ischemic cardiopathy who was admitted to our hospital for coronariographic study. Immediately after the study had been done, the patient complained of acute, intense lumbar pain with paraesthesia and progressive weakness of his legs, developing paraparesia and sphincter disorders. Magnetic resonance of the spine was done and in the spinal cord an oval lesion was seen in the medullar cone which was compatible with infarction. Six months later this finding was unchanged. CONCLUSION: A spinal infarction as a complication of invasive vascular studies, such as angiographies, is exceptional nowadays, but should be remembered as a possible adverse effect. It may be suspected in cases of acute lumbar pain with motor and sensory defects of the legs and may be confirmed on magnetic resonance studies of the spinal cord.

Coronary Angiography↗
PubMedDate not supplied

[Spatial learning and the hippocampus].

INTRODUCTION: Since publication of the book The hippocampus as a cognitive map by O'Keefe and Nadel in 1978, several theoretical and experimental works have supported the participation of the hippocampus in rodents in spatial processing. Since then, great advances have been made into understanding the potential role of the hippocampus in learning and memory processes, relegating a secondary role to the hypothesis that, in rodents, the hippocampus is restricted to the formation of a cognitive map. DEVELOPMENT: In this work, different forms of spatial navigation are analyzed (taxis, cartographic and route integration-based navigation) on a psychological and neurobiological level. The spatial function of the hippocampus proposed by O'Keefe and Nadel is discussed but a more general model is chosen that explains the function of the hippocampus in mammals, i.e. a model of relational memory. Therefore, in the context of relational memory we attempt to explain the different forms of spatial memory in rodents and present the most relevant experimental data that support a critical role for the hippocampus in this kind of memory. CONCLUSIONS: The studies reviewed in this work support an important role for the hippocampus in spatial processing. However, this does not appear to be its sole function and it possibly operates more widely also participating in relational memory.

Animals↗
PubMedDate not supplied

[Quantitative observations of non-neuronal and neuronal cells of the mammillary bodies during postnatal development].

The mammillary bodies are already shaped in the last stages of the fetal development, and you can differentiate clearly in them the medial mammillary nucleus (MMN) and lateral mammillary nucleus (LMN). All this allow to study the variations in cellular density, the relation between neuronal and glial cells, so as the number of nucleoli present in the neuronal cells and the nucleolar area variations through the postnatal development (0N, 2N, 4N, 8N, 16N and adult). The results show, demonstrate a different behaviour in the cellular stabilization and migration of the MMN and LMN, so as a cellular differentiation after 4N in both nucleus. All this is discussed with the data obtained from the nucleolar activity, as an index of synthesis and reflection of the neuronal maturing.

Animals↗
PubMedDate not supplied

The rat pinealocyte during the oestrous cycle. A morphometric study.

The involvement of the pineal gland in the oestrous cycle seems to be clear nowadays according to various types of studies, although its exact functional mechanism remains unknown. The lack of morphological studies on the pineal gland throughout the oestrous cycle has drawn us into the quantification of the surface of pinealocyte nucleoli and nuclei and lipid contents (expressed in mean area of lipid droplets with respect to the total area of pinealocytes) in each of one of the four days of the oestrous cycle: Prooestrous, oestrous, metoestrous and dioestrous. The measures of nuclei and lipid droplets were taken on photographs that were obtained from 1 micron thick sections by means of an image analyzer and the measures of nucleoli were obtained from micrography by means a point-counting analysis. One-way analysis of variance showed significant differences among nucleolar surface during the four days of the cycle. Nucleolar surface in prooestrous and oestrous was significantly smaller than in metoestrous and dioestrous and nuclear surface showed higher values in dioestrous and proestrous than oestrous and metoestrous. The relative value of lipid surface with respect to pinealocyte surface showed significant differences between oestrous and the other three days, with their minimum value in oestrous and maximum in metoestrous. We conclude that the pinealocyte have a rhythmic activity during the oestrous cycle, with a minimum close to ovulation, where the pituitary gonadotropins and ovarian hormonal levels presents a surge.

Animals↗