scispace - formally typeset
Search or ask a question

Showing papers by "University of Alcalá published in 1988"


Journal ArticleDOI
TL;DR: Increased lipoprotein lipase activity is the proposed mechanism through which the liver becomes an acceptor of circulating triglycerides, allowing their use as ketogenic substrates, so that both maternal and fetal tissues may indirectly benefit from maternal hypertriglyceridemia.

191 citations


Journal ArticleDOI
TL;DR: The reaction between (C5Me5)SiMe3 and group 4 element tetrahalides MX4 (M  Ti, Cl, Br, I, Zr, Hf, X ǫ, Cl) gives the corresponding (η5-C5me5)MX3 derivatives in nearly quantitative yields in one-step procedure without the need for further purification as discussed by the authors.

165 citations


Journal ArticleDOI
TL;DR: In this paper, the application of space-borne sensors to forest fire mapping and inventory was evaluated, and the results showed that image processing techniques cannot discriminate perfectly the area affected by the fire.
Abstract: The application of space‐borne sensors to forest fire mapping and inventory was evaluated. Digital image processing of Thematic Mapper data was used to study a big forest fire on the Mediterranean coast of Spain. The results showed that image processing techniques cannot discriminate perfectly the area affected by the fire. The main problem was spectral overlapping between burned and unburned vegetation especially caused by the sparseness of shrub and confusion with other cover types such as urban/rural villages. Most of these problems can be solved by using visual analysis for masking the affected area, although this strategy is not completely reliable on studies of small forest fires. An inventory of the damaged area was performed in three levels: total area affected by the fire, area by previous vegetation species, and identification of levels of damaged on the burned vegetation.

161 citations


Journal ArticleDOI
TL;DR: The morphometric evaluation revealed a decreased surface density of GFAP immunoreactive material in the hippocampus, globus pallidus and the ventral part of the arcuate nucleus of orchidectomized males when compared to control males, indicating that the differences in surface density represent an effect of sex steroids on the growth of astrocytic processes rather than on the proliferation ofAstrocytes.

98 citations


Journal ArticleDOI
TL;DR: The leukocyte adhesion receptors (LAR) Mac‐1 and p150,95 were thought to occur only on myeloid cells, but recently, mouse Ly‐1+ B and pro‐B cells were shown to bind M1/70 monoclonal antibody, an anti‐Mac‐1 antibody.
Abstract: The leukocyte adhesion receptors (LAR) Mac-1 and p150,95 were thought to occur only on myeloid cells, but recently, mouse Ly-1+ (CD5+) B and pro-B cells were shown to bind M1/70 monoclonal antibody, an anti-Mac-1 antibody. Using immunoprecipitation, sodium dodecyl sulfate gel electrophoresis, immunofluorescence and flow cytometry, we have studied the expression of LAR in human CD5+ B cells from chronic lymphocytic leukemia (B-CLL) patients. 170,95 kDa Mac-1 and p150,95, as well as 180,95 kDa LFA-1 heterodimers are shown to be co-expressed on CD5+ mu + kappa + B cells from a patient where they retain their known function in homotypic cell-cell adhesion. Therefore, functional Mac-1 and p150,95 LAR are not restricted to myeloid cells.

58 citations


Journal ArticleDOI
TL;DR: It is proposed that maternal thyroidectomy greatly decreases the thyroid hormone levels in embryonic structures during the first half of gestation and inhibits normal maternal metabolic changes during this period, which reduces the quantity of maternal substrates available to fetuses during the last phase of gestation.
Abstract: Female rats were mated and thyroidectomized (T) on the same day and divided into four groups. Three groups were subsequently treated daily with 1.8 micrograms L-T4/100 g body wt: 1) for the first 12 days [T + T4 (I)]; 2) from the 12th day until death [T + T4 (II)]; or 3) for the entire 21-day study [T + T4 (I + II)]. The other T animals were maintained without treatment. (T), and another group of mated rats were sham operated (C). Maternal body weight increase during gestation did not differ between T + T4 (I + II) and C dams, whereas it was smaller in T dams from the 7th gestational day onward. Neither interruption of T4 treatment in the T + T4 (I) rats after the 12th day nor treatment initiated at that time in the T + T4 (II) group modified their body weights. At day 21, the weights of the maternal conceptus-free body and liver, the placenta, and the fetuses were lower in the T and T + T4 (II) animals than in either the C and the T + T4 (I + II) animals. Maternal plasma T4 and pituitary GH content were reduced, and plasma TSH was enhanced in both T and T + T4 (I) dams. In fetuses, plasma TSH concentration was augmented in T and T + T4 (I) rats and unchanged in T + T4 (II) animals when compared with those of T + T4 (I + II). Pituitary GH content was reduced in T and T + T4 (II) fetuses and unchanged in the T + T4 (I) group. We propose that maternal thyroidectomy greatly decreases the thyroid hormone levels in embryonic structures during the first half of gestation and inhibits normal maternal metabolic changes during this period. In addition to interfering with normal fetal development, these effects reduce the quantity of maternal substrates available to fetuses during the last phase of gestation. In contrast, when maternal hypothyroidism occurs during the second half of gestation, the effects are not as detrimental because fetal thyroid gland activity is adequate, and maternal catabolic adaptations are not impaired.

51 citations


Journal ArticleDOI
TL;DR: It is concluded that the increase in TcR‐CD3−CD2+ NK cells masks the T cell reduction in aged humans by normalizing CD2+ cell frequencies, however, NK cells cannot functionally substitute the thymus‐derived lymphocytes they replace.
Abstract: While there is accumulating evidence to indicate the presence of functional abnormalities in T cells from aged healthy humans, their cellular basis remains unclear. By using two-color immunofluorescence and multiparameter flow cytometry we show that (a) the number of peripheral blood antigen receptor-positive (TcR-CD3+) T cells is significantly lower in aged than in young adults; (b) the numbers of E-rosette-forming (CD2+) cells are maintained in the elderly due to a reciprocal increase in the frequency of TcR-CD3- cells, which constitute only a minor lymphocyte subpopulation in young adults, and (c) TcR-CD3-CD2+5- lymphocytes exhibit the phenotypic features of natural killer (NK) cells. By using functional assays we show the TcR-CD3-CD2+16+ lymphocytes are indeed NK cells because they are activated by and lyse NK targets. In contrast, they are unresponsive to either phytohemagglutinin or mitogenic CD2 monoclonal antibody stimulation, which in turn activates TcR-CD3+CD2+16- T cells. We conclude that the increase in TcR-CD3-CD2+ NK cells masks the T cell reduction in aged humans by normalizing CD2+ cell frequencies. However, NK cells cannot functionally substitute the thymus-derived lymphocytes they replace.

37 citations


Journal ArticleDOI
TL;DR: The work described in this article is included in Project PR-84-0407, which is supported by CAICYT and sponsored by Repsol Petr6leo, and is described as follows:

36 citations


Journal ArticleDOI
TL;DR: Biochemical, karyological and morphological characterization of Triticum turgidum conv.
Abstract: Biochemical, karyological and morphological characterization of Triticum turgidum conv. durum/Hordeum chilense addition forms was carried out. Nine H. chilense isozyme markers, belonging to ACPH, CPX, EST, PGM, 6-PGD, GOT and MDH enzymatic systems, were used to identify the chilense chromosomes in 50 monosonic or polysomic addition forms. Several morphological traits were associated with the presence of chilense chromosome in the complement. The transmission frequencies of addition chilense chromosomes were also investigated in the offspring of various crosses.

31 citations


Journal ArticleDOI
TL;DR: In this article, the authors studied the variation of the rate and equilibrium constants of the reaction between pyridoxal 5'-phosphate (PLP) and n-hexylamine as a function of the pH at a temperature of 25 °C and an ionic strength of 0.1, in media of different polarity.

29 citations


Journal ArticleDOI
TL;DR: Feeding of male Wistar rats for 8 days with a diet containing 250 ppm of lindane resulted in a maximal accumulation of the xenobiotic in kidney followed by adipose tissue, liver, brain, and lung, and the results suggest a relationship between accumulation of lINDane and increase of phospholipid amounts in the rat tissues.

Journal ArticleDOI
TL;DR: The utilization of the infused substrate for fatty acids and glyceride-glycerol synthesis by the tissue was quantified by taking into account the infused radioactivity, the difference in the amount of 14C-labeled lipids appearing in periuterine adipose tissue on the left and the right sides, the arterial plasma concentration of the studied metabolite, and the uterine horn blood flow.

Journal ArticleDOI
TL;DR: The results suggest the importance of androgens in the biosynthesis of VIP receptors and also in their coupling to adenylate cyclase by affecting the membrane fluidity.

Journal ArticleDOI
TL;DR: It is demonstrated that adrenalectomy modulates SS receptors in discrete brain areas, suggesting the existence of a possible relationship between corticosteroids and SS in the neuronal activity of these structures.
Abstract: The effects of adrenalectomy on somatostatin (SS) concentration and specific binding in cerebral cortex, hippocampus, striatum, and hypothalamus were examined using [125I-Tyr11]SS as the binding ligand. Adrenalectomy did not affect the concentration of SS-like immunoreactivity in the brain areas studied. Nevertheless, the number of SS receptors was significantly decreased in membrane preparations from hippocampus, striatum, and hypothalamus, but not in cerebral cortex. No significant differences in the apparent binding affinity values were seen after adrenalectomy. The adrenalectomy-induced decreases in [125I-Tyr11]SS receptors were completely reversed by glucocorticoid replacement with dexamethasone. These results demonstrate that adrenalectomy modulates SS receptors in discrete brain areas, suggesting the existence of a possible relationship between corticosteroids and SS in the neuronal activity of these structures. The physiological significance of these findings remains to be clarified.

Journal ArticleDOI
TL;DR: In this article, the reaction of NbCl 3 with Me 3 SiOMe in the appropriate molar ratios has given new alkoxoniobium(V) derivatives of the type NbCL 5− x (OMe) x ( x = 2 (I), 3 (II)).

Journal ArticleDOI
TL;DR: In this paper, 14 wines from Mentrida (Toledo, Spain) were examined by atomic absorption spectrophotometry (AAS) in order to measure the concentrations of Fe, Cu, Zn, Mn, and Ph, using two different methods of sample preparation for the metal analyses: analysis of untreated samples and analysis of wet-mineralized samples.
Abstract: Fourteen wines from Mentrida (Toledo, Spain) were examined by atomic absorption spectrophotometry (AAS) in order to measure the concentrations of Fe, Cu, Zn, Mn, and Ph, using two different methods of sample preparation for the metal analyses: analysis of untreated samples and analysis of wet-mineralized samples. This was camed out in order to elaborate a suitable method for their determination after studying the possible matrix effects originating in either the organic or inorganic components. The influence of the vinification system on trace metal content and the stability and salubrity of these wines in relation to certain toxic metal concentrations was also examined.

Journal ArticleDOI
TL;DR: In vitro protoscolices of Echinococcus granulosus grew in a vesicular direction and the existence of a germinal layer was demonstrated and the ultrastructure of these cysts was studied.
Abstract: In vitro protoscolices of Echinococcus granulosus grew in a vesicular direction. After 9 days the laminated layer was observed; it reached thicknesses up to 140 Μm. By day 125 of culture, the cysts had reached sizes of up to 4.875 Μm and a high percentage of cysts had been obtained (10.4%). The ultrastructure of these cysts was studied and the existence of a germinal layer was demonstrated.

Journal ArticleDOI
TL;DR: In this article, the authors acknowledge financial support from the Comision Asesora de Investigacion Cientifica y Tecnica (CACI) and the National Institute of Aeronautics and Astronautics (INAH).

Journal ArticleDOI
TL;DR: The interaction of insulin with its specific receptors was studied in jejunoileal epithelial cells from 14, 20, and 60-day-old rats and results support previous suggestions on the potential role of insulin on the mechanisms of differentiation and proliferation of small intestinal mucosa.
Abstract: The interaction of insulin with its specific receptors was studied in jejunoileal epithelial cells from 14-, 20-, and 60-day-old rats. Characteristics such as potency and specificity of the insulin receptor system did not vary during development. However, insulin binding decreased with age due to a diminished concentration of insulin receptors, whereas the circulating levels of the hormone followed an inverse evolution. These results support previous suggestions on the potential role of insulin on the mechanisms of differentiation and proliferation of small intestinal mucosa.

Journal ArticleDOI
TL;DR: Spermatozoa are compared among flatworms, and some considerations on the significance of their ultrastructure for phylogeny in the Platyhelminthes are tentatively given.
Abstract: The spermatogenesis and mature spermatozoon of Paravortex cardii were studied by transmission electron microscopy. Meiotic divisions occur without cytokinesis and the spermatid nuclei appear embedded in a common cytoplasmic mass. The mature spermatozoon is filiform, very regular in contour and circular in cross-section. A tubular lining of microtubules lying close to the plasma membrane is found along the spermatozoon. Rows of spherical glycogen particles with helical arrangement lay internal to the cortical microtubules. The spermatozoon of P. cardii may be divided into two regions, nuclear and cytoplasmic regions. The nuclear region contains an elongated nucleus with a densely packed nuclear material. The mitochondria are distributed throughout the cytoplasmic region; they pack tightly together and often fuse to form one large one. This spermatozoon lacks both acrosome and the so-called dense bodies. A ciliary or centriolar apparatus was not observed. Accordingly, the spermatozoon of P. cardii is considered to be aflagellate in type. Spermatozoa are compared among flatworms, and some considerations on the significance of their ultrastructure for phylogeny in the Platyhelminthes are tentatively given.

Journal ArticleDOI
TL;DR: It is suggested that disintegration of phagocytic cells during starvation is balanced by proliferation and differentiation of neoblasts into new phagocytes during the feeding-starvation cycle.
Abstract: In the present report the functional morphology of the planarian gastrodermal phagocytic cells is examined in feeding animals. A functional interpretation of some of the morphological findings is given. The events in the fine-structure modifications of the phagocytic cells in the course of phagocytosis and intracellular digestion of food particles were followed through five post-feeding stages in the planarian Dugesia gonocephala. Light and electron microscopical observations demonstrate that there is preliminary intraluminal digestion of food particles; their phagocytosis takes place quickly.

Journal ArticleDOI
TL;DR: The use of phase transfer catalysis and ultrasound stirring improved the synthesis, alkylation and hydrolysis of several Reissert derivatives as mentioned in this paper, and improved the performance of the synthesis.

Journal ArticleDOI
TL;DR: It is proposed that etofibrate enhances the reesterification of fatty acids and glycerol in adipose tissue, which, together with its augmented lipoprotein lipase activity, may facilitate the clearance of circulating triacylglycerols.

Journal ArticleDOI
TL;DR: The infrared and 1 H and 13 C NMR spectra of 3-phenethyl, 3-azabicyclo [3.3.1] decan, 10α-ol (II) have been examined in several media as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this paper, the reduction of the niobocene complexes Nb(η 5 -C 5 H 3 RR′) 2 Cl 2 with one equivalent of (1%) sodium amalgam in the presence of an isocyanide ligand R″NC yields Nb

Journal ArticleDOI
TL;DR: Evidence is reported that the addition of glucose to digitonin-permeabilized Ehrlich ascites tumor cells causes a decrease of mitochondrial membrane potential that coincided with a transient enhancement of the respiration rate and remained unchanged during the subsequent Crabtree effect.

Journal ArticleDOI
TL;DR: Results suggest the existence of differences in calcium movements in response to caffeine between control and sensitized tissues that may reflect abnormalities in calcium handling by the sensitized tissue.

Journal ArticleDOI
TL;DR: It is suggested that mild temperature initiates testicular development in the period of testicular quiescence, long photoperiods associated with mild temperatures produce spermatogenesis in this period, complete darkness or constant light are less effective than some intermediatePhotoperiod, and the effect of photoperperiod on testicular function in newts is not related to ocular photoreception.
Abstract: Adult male marbled newts (Triturus marmoratus) were collected at the end of the spermatogenesis period and exposed to different photoperiods (natural-daylength-simulated photoperiod, total darkness, 8L:16D, 12L:12D, 16L:8D, and continuous light) for 3 mo. Temperature was maintained at 20 degrees C. Two additional groups of newts were blinded and exposed to either the natural-simulated photoperiod and to 16 h of light per day respectively. Quantitative histologic studies on testicular development and germ cell volume per testis were performed. The newts captured in the field at the beginning (initial controls) or at the end of the experiments (final controls) were in the period of testicular quiescence. Newts kept in total darkness or exposed to a short photoperiod (8L:16D) showed germ cell development up to primary spermatocytes, whereas germ cell development in the newts exposed to long photoperiods (12L:12D or 16L:8D) progressed to elongated spermatids. The newts exposed either to intermediate photoperiods (natural-simulated photoperiod) or to constant light showed an intermediate degree of germ cell development (up to round spermatids). No significant differences between non-blinded and blinded animals were found. These results suggest that (1) mild temperature initiates testicular development in the period of testicular quiescence, (2) long photoperiods associated with mild temperatures produce spermatogenesis in this period, (3) complete darkness or constant light are less effective than some intermediate photoperiod, and (4) the effect of photoperiod on testicular function in newts is not related to ocular photoreception.

Journal ArticleDOI
TL;DR: The existence of two primary divisional or lobar branches of the splenic artery and their respective territories or lobes is confirmed and the secondary or segmental branches and their vascular territories were studied; an average of 6 segmental territories was found.
Abstract: The authors have conducted a corrosion cast study of the human spleen to systematize the branches of the splenic artery and the vascular territories irrigated by them. The existence of two primary divisional or lobar branches of the splenic artery and their respective territories or lobes is confirmed. The secondary or segmental branches and their vascular territories were studied; an average of 6 segmental territories was found. These findings are compared with those reported in the literature.

Journal ArticleDOI
TL;DR: A series of N-β(γ)-acyloxyalkylnortropinones have been synthesized and studied by 1H and 13C nmr spectroscopy, and the crystal structure of N-[γ-(p-chlorophenylcarbonyloxy)propyl]nornropinone 4 has been determined by X-ray diffraction as mentioned in this paper.