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Biomedical subjects

P Quesada

Publications and source records attributed to P Quesada.

17 recordsLinked to original sources
PubMed1991

In vitro poly(ADPribosylation) of estrogen-induced proteins from the oviduct of the lizard Podarcis s. sicula Raf.

Poly(ADPribosylation) of nuclear proteins has been investigated in the nuclei from growing oviducts of intact and estrogen-treated spayed females of the lizard Podarcis s. sicula Raf. Isolated nuclei were incubated with [14C] NAD and nuclear proteins extracted in 0.2 m H2SO4. Labeled acid-soluble proteins were analysed by reverse-phase high-performance liquid chromatography (HPLC) and acetic acid-urea gel electrophoresis. The results reported here indicate that the ADPribosylation reaction is involved in modifying besides histone H2b, tissue specific proteins (SNPs and LMG-O). Moreover, comparable results have been obtained from nuclei prepared from the fully active oviduct of intact animals and spayed lizards stimulated with 17 beta-estradiol. It is concluded that the poly-(ADPribosylation) of hormone-induced proteins might play a role in the differentiation of the lizard oviduct.

Amino Acids↗
PubMed1991

Cell cycle perturbating agents in a line of human thyroid transformed cells in culture (HuT).

Culture and differentiation parameters of a human thyroid transformed cell line (HuT) were analyzed. Treatment with high concentrations of chemical agents namely dimethyl sulphoxide and retinoic acid, exerted a dramatic cytotoxic effect. The exposure of these cells to the lowest doses of retinoic acid as well as to 8 mM-16 mM 3-aminobenzamide a potent inhibitor of poly(ADPribose)polymerase, resulted in a delay of cell proliferation. Poly(ADPribose)polymerase activity was differently affected by retinoic acid (stimulation) and 3-aminobenzamide (inhibition).

Benzamides↗
PubMed1991

Extramedullary nasal plasmacytoma.

The literature on this rare tumour has been reviewed and three cases of nasal plasmacytoma are described. Immunohistochemistry demonstrated cytoplasmic IgA and Kappa determinants in all cases. Two patients are disease-free at the present time, the third developed an IgG-k multiple myeloma, previously not described in the literature.

Aged↗
PubMed1991

Acute epiglottitis in the adult.

Acute epiglottitis in the adult is a rare disease, which has shown an appreciable increase since the sixties and in our locality since 1984. We present a review of the cases registered in our hospital, analyzing their aetiology, evolution and treatment. The disease is most likely to be suspected in the presence of any patient having a sudden dysphagia, especially if he shows symptoms of an acute infection and a lack of oropharyngeal pathology.

Acute Disease↗
PubMed1991

Reciprocal inhibition between forearm muscles in spastic hemiplegia.

We studied reciprocal inhibition of H-reflexes in the forearm flexor and extensor muscles in 14 patients with spastic hemiplegia secondary to a focal cerebral lesion and 14 normal volunteers. In the spastic limb, the Hmax/Mmax ratio was increased in both flexor and particularly extensor wrist muscles. The 3 normal inhibitory phases of reciprocal inhibition between extensor and flexor forearm muscles were markedly reduced on the spastic side of patients. The early disynaptic phase showed the greatest alteration. Reduced or absent inhibition between forearm muscles associated with increased spinal motoneuron excitability may be typical to spastic hemiplegia.

Brain Diseases↗
PubMed1991

Analysis of a below-knee patellar tendon-bearing prosthesis: a finite element study.

In this study, a finite element (FE) model of a below-knee prosthesis of patellar tendon-bearing (PTB) design, and several altered variations of the model have been constructed. A load of approximately 1.5 times normal body weight (984 N) was applied at the heel of the model to simulate heelstrike conditions. The "base" model was then analyzed and revised iteratively until a model which provided consistency between soft tissue elastic modulus and socket displacement was developed. The interface normal and shear stresses obtained from the analysis of this revised base model were highest (about 961, and 463 KPa, respectively) at the distal anterior tip of the socket/stump. Proximally, higher normal stresses (72-78 KPa) were found medially and posteriorly. Proximal shear stresses were highest posteriorly (79 KPa), although shear stresses medially (51 KPa), and laterally (43 KPa), were also much higher than anteriorly (10 KPa). FE analyses were performed on the altered models to determine the relative effects on socket/stump interface stresses of altering the FE model of the prosthesis. Results of the analysis indicate that fabricating the prosthesis from a material with an elastic modulus ten times lower than that of the revised base model can produce reductions in the maximum pressure of up to 14 percent. Large decreases in maximum pressures (71 percent) resulted from the use of a suction socket rather than a conventional socket. Small changes in stump length (2 cm) caused relatively large pressure changes (16 to 18 percent).

Amputation, Surgical↗
PubMed1991

[The electronystagmographic protocol for tracking vestibular dysfunction].

This prospective protocol for vestibular exploration offers the results gained through 296 patients complaining from vestibular disorders. The aim of the AA. is to check the validity of the test proposed (in the midst of the battery of electronystagmographic explorations), consisting in the thermal bilateral and simultaneous stimulation of the labyrinths. They consider this trial very useful because of its sensibility, quickness and tolerance.

Electronystagmography↗
PubMed1990

ADP-ribosylation of nuclear proteins in rat ventral prostate during ageing.

Poly(ADPR)polymerase activity and poly(ADP-ribosyl)ation of nuclear proteins have been investigated in ventral prostate nuclei of different aged rats (14, 28, 60, 180, 360 day old animals), by reverse-phase HPLC and acetic acid-urea polyacrylamide gel electrophoresis. The major ADP-ribose acceptor proteins were identified as histone H1 and H2b. It is concluded that concomitant with major changes to chromatin organization, poly(ADP-ribosyl)ation reaction is progressively inhibited during aging of rat ventral prostate. These results support the hypothesis that prostatic dysfunction in senescent animals is related to a failure of DNA repair mechanisms and deregulated template activity.

Aging↗
PubMed1990

In vitro inhibition of HeLa cell nuclear ribonucleases by ADP-ribosylation.

Ribonuclease activity in HeLa cell nuclei is markedly inhibited by ADP-ribosylation following incubation of intact isolated nuclei with [14C]NAD. Time course experiments demonstrate that [14C] incorporation into proteins is accompanied by a 50% inhibition of ribonuclease activity on single-strand and double-strand polynucleotides. Inhibition does not occur when 3-aminobenzamide, a potent (ADP-ribose) polymerase inhibitor, is present. Two enzymatic activities that degrade double-strand polynucleotides have been purified and partially characterized. A relevant level of radioactivity resulting from [14C]NAD incubation of nuclei was associated to the purified enzyme. The RNase F1 component, which shows maximal activity on polyU-polyA is demonstrated to be the major ADP-ribose acceptor protein.

Cell Nucleus↗
PubMed1990

Eosinophilic granuloma of the temporal bone.

Involvement of the temporal bone by eosinophilic granuloma is rare. Two cases are presented and their clinical manifestations, histopathological findings and treatment procedures discussed.

Adult↗
PubMed1990

Nasal myiasis due to Oestrus ovis larvae.

Herein we report our experiences in managing nasal infestation due to fly larvae in an urban population. The nasosinus location is infrequently seen in cases with human infection. The life cycle of the fly (Oestrus ovis) is discussed in view of the clinical features of our case.

Adult↗
PubMed1990

Tightly-bound form of poly(ADP-ribose)polymerase in the higher order of chromatin organization.

A tightly-bound form of poly(ADP-ribose)polymerase is present, within the third level of rat testis chromatin structure, both in the loops and in chromatin matrix. When chromatin matrix was extensively digested with DNAaseI, only little residual enzymatic activity remained in the insoluble fraction, the extent of DNA hydrolysis being well correlated to the progressive loss of the poly(ADP-ribose)polymerase activity. These findings suggest that the tightly-bound form of the enzyme is not an intrinsic protein component of chromatin matrix but is only indirectly located in this structure, being rather associated to the attachment points of loop DNA on the matrix.

Animals↗
PubMed1989

Poly(ADP-ribosylation) of nuclear proteins in rat testis correlates with active spermatogenesis.

Poly(ADP-ribosylation) of nuclear proteins has been investigated in rat testis under different experimental conditions to determine whether it is associated with somatic or germinal cells. Isolated, intact nuclei were incubated with [14C]NAD and extracted sequentially with 5% HClO4 and 0.25 M HCl, and labelled soluble proteins were analysed by reverse-phase high-performance liquid chromatography and acetic acid-urea polyacrylamide gel electrophoresis (pH 2.9). Results show that in normal adult testis a major acceptor protein for poly(ADP-ribose) in HClO4 extracts is the tissue-specific histone, H1t. Core histones and three proteins (alpha, beta and gamma) with low mobility on acetic acid-urea gels were the major acceptors identified in HCl extracts. Poly(ADP-ribosylation) of all the aforementioned proteins is very low in isolated intact nuclei of testis from 8-day-old animals (only spermatogonia present in seminiferous tubules), increases significantly by 16-day (pachytene spermatocytes appear) and reaches adult proportions by 32 days (condensing spermatids present). In the nuclei from cryptorchid testes, poly(ADP-ribosylation) of nuclear proteins resembles 8-day-old testis. It is concluded that (a) poly(ADP-ribosylation) of nuclear proteins in rat testis is closely correlated with spermatogenesis and can be inferred that is particularly active in the early stages of meiosis; (b) testis-specific proteins (histone H1t and low mobility proteins, alpha, beta and gamma) are poly(ADP-ribosylated) to higher specific radioactivity than somatic histones.

Age Factors↗
PubMedDate not supplied

Poly(ADP-ribose)synthetase from HeLa cell nuclei: purification and properties.

Poly(ADP-ribose)synthetase has been purified over 600-fold from HeLa cell nuclei. Upon electrophoresis on 9% polyacrylamide slab-gel in the presence of SDS, the purified enzyme resolved in two bands that showed similar apparent Mr values, 110,000 and 118,000. The aminoacid composition of the two components differed from compositions reported for the same enzyme from other sources. In accordance with other reports, the enzyme purified from HeLa cell nuclei exhibited an absolute dependence on DNA and its activity was modulated by changes in the histone concentration. Incubation of intact nuclei from HeLa cells with [14C]NAD resulted in the isolation of a poly(ADP-ribose)synthetase to which a definite radioactivity is bound. These results are taken as a further demonstration that the enzyme can be auto-ADP-ribosylated.

Adenosine Diphosphate Ribose↗