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P Quesada

Publications and source records attributed to P Quesada.

At least 73 records · Page 4Linked to original sources
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↗
PubMed1987

In vitro ADP-ribosylation of nuclear proteins in mouse tissues. Identification of an unusual group of acceptors in testis nuclei.

1. Acceptor proteins for poly(ADP-ribose) have been identified in nuclei from mouse testis, liver, kidney and spleen. Purified nuclei were incubated in vitro with [14C]NAD, extracted sequentially with 5% HClO4 and 0.25 N-HCl and labelled proteins analysed on acetic acid/urea polyacrylamide gels pH 2.9. 2. Results show that: (a) in vitro there are significant differences between tissues in the extent of poly(ADP-ribosylation) of nuclear proteins; (b) in testis nuclei two tissue specific proteins are poly(ADP-ribosylated) to higher specific activity than histones; (c) there are significant differences between in vivo and in vitro studies on poly(ADP-ribosylation) of nuclear proteins in testis nuclei.

Adenosine Diphosphate Ribose↗
PubMed1986

In vitro poly(ADP-ribosyl)ation of seminal ribonuclease.

The site of in vitro ADP-ribosylation of seminal ribonuclease was determined. Seminal enzyme was found to be a good receptor of [14C]ADP-ribose residues under the reaction conditions used. The recovery of [14C]ADP-ribosylated RNase was about 65% after purification. After tryptic digestion of modified enzyme, a fraction containing [14C]ADP-ribosylated peptides was separated from the others by ion-exchange chromatography on M82 resin. Radioactive peptides were then purified by affinity chromatography on anti-poly(ADP-ribose)IgG-Sepharose. High performance liquid chromatography of a mixture obtained after pronase digestion of purified ADP-ribosylated peptides revealed only one radioactive peptide whose amino acid composition corresponded to a peptide that has equimolar quantities of aspartic acid, serine, and glycine. Carboxypeptidase Y digestion of this peptide showed that its amino acid sequence was Asp-Ser-Gly. Only position 14-16 of seminal RNase corresponded to this sequence. The chemical stability of the ADP-ribose/enzyme linkage indicated that aspartic acid 14 is the modification site in seminal RNase.

Amino Acid Sequence↗
PubMed1984

Purification of non-histone acceptor proteins for ADP-ribose from mouse testis nuclei.

Acceptor proteins for poly(ADP-ribose) have been purified from mouse testis nuclei. Nuclear proteins were labelled in vitro with [14C]ribose and [3H]adenine, extracted with 5% (v/v) HClO4 and 0.25 M-HCl and separated by ion-exchange chromatography. Non-histone proteins were found to be the major acceptors in both the 5% (w/v)-HClO4-soluble and 5%-HClO4-insoluble HCl-extractable fractions. Of the two groups of non-histone proteins associated with chromatin, the LMG (low-mobility-group) proteins were preferentially ADP-ribosylated. HMG (high-mobility group) proteins were labelled to lower specific radioactivity. Six LMG proteins were purified to approx. 90% homogeneity and were identified from their mobility on polyacrylamide gels at pH 2.9 and from their amino acid composition. The average length of the poly(ADP-ribose) chain was estimated to be four to six repeating ADP-ribose units. It is suggested that ADP-ribosylation of LMG proteins, a long-neglected group of chromatin-associated proteins, is important during spermatogenesis for the production of spermatozoa with intact and competent DNA.

Adenosine Diphosphate Ribose↗
PubMed1982

ADP-ribosylation of nuclear proteins in mouse testis.

The nuclear acceptor proteins for poly(ADP-ribose) were investigated in mouse liver and testis. In liver, histones are ribosylated preferentially, whereas in testis the major acceptors are non-histone proteins. An analysis of the purified testicular acceptor proteins suggests that they are high- and low-mobility-group-like proteins.

Amino Acids↗