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P Diaz

Publications and source records attributed to P Diaz.

At least 55 records · Page 3Linked to original sources
PubMed1991

Loss of secreted hemolysin activity in the mutant strain Hsb. 1 is due to a lesion in a plasmid copy number locus.

Further studies have been carried out on mutation hsb which was previously suggested to block hemolysin secretion (Muñoa et al., 1988, FEMS Microbiol. Lett. 56: 167-172). We show that the reported reduction in the extracellular hemolytic activity of mutant Hsb. 1 is due to lower hemolysin synthesis and that this is itself a consequence of a decrease in plasmid copy number. We suggest that the hsb is identical to the pcnB lesion located at minute 3.6 of the chromosome.

Chromosomes, Bacterial↗
PubMed1991

Prevalence of antibodies to HTLV-1 in South American Indians (Mapuches) from Chile.

The seroprevalence of HTLV-1 antibodies was investigated in 405 serum samples from healthy South American Indians (Mapuches) from Chile, using enzyme linked immunoassay (ELISA), Western immunoblot (WB) and radioimmuno precipitation assay (RIPA). Six samples were positive by ELISA; 3 of them were confirmed by WB/RIPA. Thus, we observed a seroprevalence of 0.7% for HTLV-1 antibodies in healthy Mapuches.

Blotting, Western↗
PubMed1989

Leukocytes and mediators in bronchoalveolar lavage during allergen-induced late-phase asthmatic reactions.

We have measured the total and differential cell counts, histamine, leukotriene (LT) B4 and LTC4, immunoglobulins, complement (C3), eosinophil-derived basic proteins, and monocyte complement rosettes in bronchoalveolar lavage (BAL) 6 h after challenge with either antigen or diluent control in seven patients with antigen-induced single early reactions, and seven with dual (early and late phase) reactions. In both groups, the total cell counts in BAL were similar, irrespective of whether they were challenged with antigen or diluent. However, in the late-phase responders (LPR), there were significant increases in lymphocytes, neutrophils, and eosinophils (p less than 0.05), and significant decreases in the percentage of lung mast cells (p less than 0.05). The eosinophil major basic protein and eosinophil-derived neurotoxin increased in four of five subjects with dual responses and in the majority of single early responders (SER). BAL histamine concentrations increased in five of seven patients with dual responses. There were no consistent changes in LTB4 concentrations in either the LPR or the SER between diluent and antigen days, but a small but significant increase in LTC4 was observed in the LPR. Concentrations of IgG, IgA, IgM, IgE, C3, and albumin did not differ significantly. The percentage of monocyte complement rosettes also increased significantly (p less than 0.05) in LPR, but not in SER. These findings support the hypothesis that eosinophils and their products play a role in tissue injury in LPR and that eosinophil infiltration may be associated with macrophage activation.

Adolescent↗
PubMed1988

Association of nucleosome core particle DNA with different histone oligomers. Transfer of histones between DNA-(H2A,H2B) and DNA-(H3,H4) complexes.

In non-denaturing low ionic strength gels, the titration of core DNA with H2A,H2B produces five well-defined bands. Quantitative densitometry and cross-linking experiments indicate that these bands are due to the successive binding of H2A,H2B dimers to core DNA. Only two bands are obtained with DNA-(H3,H4) samples. The slower of these bands is broad and presumably corresponds to two complexes containing one and two H3,H4 tetramers, respectively. In gels of higher ionic strength, DNA-(H2A,H2B) samples produce an ill-defined band, suggesting that the lifetime of the complexes containing H2A,H2B is relatively short. However, the low intensity of the free DNA band observed in these gels indicates that most of the DNA is associated with H2A,H2B. In agreement with this, our results obtained using different techniques (sedimentation, cross-linking, trypsin and nuclease digestions, and thermal denaturation) demonstrate that the association of H2A,H2B with core DNA occurs in free solution in both the absence and presence of NaCl (0.1 to 0.2 M). The low mobilities of DNA-(H2A,H2B) complexes, together with sedimentation and DNase I digestion results, indicate that the DNA in these complexes is not folded into the compact structure found in the core particle. Furthermore, non-denaturing gels have been used to study the dynamic properties of DNA-(H2A,H2B) and DNA-(H3,H4) complexes in 0.2 M-NaCl. Our results show that: (1) H2A,H2B and H3,H4 can associate, respectively, with DNA-(H3,H4) and DNA-(H2A,H2B) to produce complexes containing the four core histones; (2) DNA-(H2A,H2B) and DNA-(H3,H4) are able to transfer histones to free core DNA; (3) an exchange of histone pairs takes place between DNA-(H2A,H2B) and DNA-(H3,H4) and produces complexes with the same histone composition as that of the normal nucleosome core particle; and (4) although both histone pairs can exchange, histones H2A,H2B show a higher tendency than H3,H4 to migrate from one incomplete core particle to another. The complexes produced in these reactions have the same compact structure as reconstituted core particles containing the four core histones. Our kinetic results are consistent with a reaction mechanism in which the transfer of histones involves direct contacts between the reacting complexes. The possible participation of these spontaneous reactions on the mechanism of nucleosome assembly is discussed.

Animals↗
PubMed1988

Training of conversational skills with institutionalized elderly: a preliminary study.

16 residents in a Residential Care Home for elderly people volunteered and were trained in a social skills program aimed at increasing conversational skills. Subjects were assigned randomly to three groups, one experimental and two control groups (placebo and waiting list). The techniques used in the experimental group were behavior rehearsal, feedback, modeling, discriminative reinforcement, verbal instructions, and homework. Relative to control groups, experimental subjects showed significant increases in conversational skills, such as receiving information, speaking-up, and giving information. They also showed a significant decrease in their scores on Zung's Self-rating Scale of Depression compared with the two control groups. They showed an increase in assertive responses and a decrease in aggressive and inhibited responses. These changes remained when follow-up was made 3 mo. later, suggesting the potential utility of this training program with elderly persons residing in old people's homes.

Aged↗
PubMed1987

Stereotactic evacuation and local administration in intracerebral haematomas. A comparative study.

Based on current controversies on optimal treatment for spontaneous intracerebral haematomas, chronic experiments to investigate the validity of open surgery, stereotactic evacuation and local urokinase administration in these lesions were performed in 52 dogs. Under general anesthesia diverse volumes of autologous blood were intracerebrally injected to produce the haematoma. A catheter was introduced and chronically implanted in the contralateral ventricle for intracranial pressure monitoring. The animals were divided in two groups of 26 dogs each, according to haematoma location in subcortical or basal ganglia structures. The natural history was studied in both groups. Different types of treatment consisting in surgery, stereotactic evacuation, urokinase injection within the clot and both latter techniques combined were carried out 24 or 72 hours following haematoma production. Clinical status, systemic arterial pressure, intracranial pressure and CT scanning were used for result evaluation. Brain specimens were submitted for pathological examination. Our results indicate that stereotactic evacuation performed during the first 24 hours after haematoma occurrence was the most effective and innocuous procedure for basal ganglia lesions. Local urokinase plus stereotactic aspiration showed a high efficacy in controlling delayed basal ganglia and subcortical blood collections. Other therapeutic approaches behaved almost as the natural history.

Animals↗
PubMed1987

Dorsal root entry zone lesion versus spinal cord stimulation in the management of pain from brachial plexus avulsion.

In six patients with total or partial brachial plexus avulsion, spinal cord stimulation was tried as pain treatment. Two patients had had amputation of the arm and suffered from phantom limb and stump pain. After a mean follow-up of 14 months two patients were painfree, one had partial relief and required analgesics and in three patients there was no effect. In eleven patients, including the three patients in whom spinal cord stimulation had failed to produce a long-lasting pain relief, dorsal root entry zone (DREZ) lesions were performed. At early follow-ups all these patients reported substantial pain relief, but after a mean follow-up of 17 months the results were less favorable: Three patients were pain-free, three had a marked improvement and five had recurrence of the original pain. Neither of the two methods of treatment produced any serious side-effects or permanent sequelae.

Adult↗
PubMed1987

Description of a case of rhinosporidiosis in Spain.

Rhinosporidiosis is reviewed, and the first autochthonous case in Spain is presented (site: in the nasal cavity of a 19-year-old male from a rural background). Diagnosis was established morphologically after eliminating the possibilities of Cryptococcus neoformans, Coccidioides immitis, and Chrysosporium crescens. Clinico-pathological features are described. Preparations were stained with hematoxylin-eosin, PAS, and methenamine silver, and studied for fluorescence. Certain aspects of the epidemiology and diagnosis are commented upon.

Adult↗
PubMed1987

Scintigraphic evaluation of reflex sympathetic dystrophy: comparative study of the course of the disease under two therapeutic regimens.

A study was made of 26 patients diagnosed as phase I reflex sympathetic dystrophy. In all of them, a bone:soft tissue uptake index was quantified by scintigraphic scanning before treatment and 3 months later. Eighteen patients were treated with 100 MRC units salmon calcitonin, followed by 500 mg elemental calcium 4 hours after hormone administration. The treatment was administered 10 days a month separated by intervals free of therapy. The other 8 patients were treated without interruption with 500 mg naproxen every 12 hours. In the group treated with calcitonin and calcium, the uptake index declined from 13.3 +/- 8.2 to 4.1 +/- 1.8 (p less than 0.001). The uptake index rose from 2.1.3 +/- 17.7 to 31.1 +/- 23.0 (NS) in the naproxen group. Using the Student t-test for paired samples to evaluate individual changes, a highly significant difference was reached (p less than 0.005) in the calcitonin-calcium group. The difference was also significant (p less than 0.01) in the naproxen group, but it was negative (t = 3.620). These results confirm the efficacy of treating reflex sympathetic dystrophy with calcitonin and calcium and the superiority of this treatment as compared with nonsteroidal anti-inflammatory drugs.

Adult↗
PubMed1987

Allergen-induced recruitment of bronchoalveolar helper (OKT4) and suppressor (OKT8) T-cells in asthma. Relative increases in OKT8 cells in single early responders compared with those in late-phase responders.

We measured the numbers of helper (OKT4) and suppressor (OKT8) T-cells in blood and bronchoalveolar lavage (BAL) in 6 patients who developed single early reactions after allergen inhalational challenge and in 6 subjects who developed dual (early- and late-phase) responses. The asthmatics were lavaged twice. On the first occasion, they inhaled the diluent control (Dil) solution, and after an interval of at least 7 days, allergen (Ag) inhalational challenge was undertaken. Significant differences were observed in the single early responders (SER) only. For instance, when the results obtained on the Dil day were compared with those obtained on the Ag day, there was a significant (p less than 0.05) increase in the percentage of OKT4 cells in the blood of SER. Also in the BAL of SER there was a significant (p less than 0.05) decrease in the percentage of OKT4 and an increase (p less than 0.05) in the percentage and absolute numbers of OKT8 cells. Furthermore, the percentage of OKT4 was highly significantly (p less than 0.005) lower on the Ag day in the SER than on the Ag day in the late-phase responders (LPR). The OKT4/OKT8 ratio was significantly (p less than 0.05) lower on the Ag day than on the Dil day in BAL from SER and highly significantly decreased (p less than 0.001) when results on the Ag day in the SER were compared with those on the Ag day in the LPR. These findings raise the possibility that mobilization of suppressor T-cells into the lung after allergen-induced single early reactions in asthma might be associated with the prevention of a subsequent late-phase response.

Adult↗
PubMed1987

Cryptorchidism: a morphological study of 670 biopsies.

Among a series of 512 boys with an empty scrotum, 495 (96.7%) were found to have cryptorchidism, 4 had ectopia and 13 unilateral anorchia. Cryptorchidism was bilateral in 106 boys (21.4%). The only anomaly consistently associated with cryptorchidism was a detached epididymis, present in 31 patients. A total of 670 biopsies were studied, 441 of which came from cryptorchid and 229 from scrotal testes. Spermatogonial counts, performed according to Mancini's method, showed the germ cell population to be diminished in nearly all cryptorchid testes. The seven boys who still had a well preserved germ cell population were found in a group of 51 patients operated before age three; four of the seven boys with normal counts were below age one. No difference in the mean spermatogonial counts was found between uni- und bilateral cryptorchidism and ectopia, with the exception of bilaterally intraabdominal testes whose spermatogonial cell loss was particularly severe. Mean counts remained constant during childhood, no gradual increase with age having been observed. The scrotal testes in unilateral cryptorchidism showed cell loss in 30.1% of the cases, the germ cell depletion being severe in one out of every six cases. In the remaining scrotal testes, the counts were in the low normal range with a significantly lower mean than that found in scrotal testes associated with anorchia. Control biopsies were performed several months or years after orchidopexy in 18 boys with unilateral and in 24 boys with bilateral cryptorchidism. Orchidopexy does not improve the number of germ cells in either originally cryptorchid or in scrotal testes, the only postoperative change being an increase in tubular diameter. A search for malignant tumours which could have developed in this series has remained negative. According to our data, no optimal time for orchidopexy can be proposed. The damage to germ cells, once established, seems to remain unchanged during childhood at least after age three, and does not warrant special timing for operative correction of cryptorchidism.

Adolescent↗
PubMed1986

Nucleosome core particle self-assembly kinetics and stability at physiological ionic strength.

Micrococcal nuclease, DNase I, and trypsin have been employed to study the kinetics of core particle self-assembly by salt jump from 2.0 to 0.2 M NaCl. A few seconds after the initiation of the reassociation reaction, the bulk of core particle DNA becomes protected from digestion by micrococcal nuclease, whereas free DNA, under the same conditions, is completely hydrolyzed. The central and C-terminal regions of core histones are also protected from trypsin digestion immediately after the 2.0-0.2 M NaCl salt jump. Moreover, the extent of degradation produced by trypsin is the same for samples digested a few seconds after the salt jump and for samples digested 20 min after the salt jump. With DNase I, minor structural differences have been detected between samples obtained at different times during the reaction. However, even in this case our results indicate that many of the characteristic histone-DNA contacts within the core particle are made a few seconds after the initiation of the self-assembly reaction. Furthermore, core particles have been labeled with the fluorescent reagent N-(1-pyrenyl)maleimide (NPM), which was previously used as a sensitive probe for nucleosome conformation. Extensive DNase I or trypsin digestion of NPM-labeled core particles in 0.2 M NaCl does not produce significant changes in excimer fluorescence. This allows us to conclude that the covalent continuity of DNA is not required for the maintenance of the folded conformation of the core particle and that the trypsin-resistant domains of core histones play a fundamental role in the stabilization of this structure.

Animals↗
PubMed1986

Intracranial malignant lymphoma. Report of 30 cases and review of the literature.

Although primary malignant lymphoma is a rare entity in the gamut of intracranial tumors, it is more frequently seen than the secondary intracranial spread of a primary extracranial lymphoma. In general, the occurrence of lymphomas seems to be provoked by immunosuppression, as with medication (predominantly after transplantation) or with immunodepressive disease such as acquired immunodeficiency syndrome (AIDS). The usual age of onset of this disease is 55 to 65 years; and the male:female patient distribution is roughly 2:1. Characteristically, computerized tomography (CT) scans of lymphomas show a mass which is often large with regular contours, moderate mass effect, and hyper- or isodensity with marked and often homogeneous enhancement. In the series of 30 patients reported, the locations of lesions, in order of decreasing frequency, were the frontocallosal and temporal regions, the basal ganglia, and the cerebellum. Multiple lesions were present in 15% of these cases (20% to 40% in the literature). The following features should raise the suspicion of intracranial lymphoma: mirror lesions of the basal ganglia, bilateral subependymal infiltration, and leptomeningeal involvement contiguous with an intracerebral mass. According to the literature, the angiographic finding typical of lymphoma is an avascular tumor. A blush or vascular encasement of the mass seems to be rare, and the present series was in accordance with other reports in this respect. Differential diagnostic consideration should include meningioma, glioblastoma, metastatic disease, and focal infectious lesions such as toxoplasmosis or multifocal progressive leukoencephalitis, particularly in immunodepressed subjects. Diagnosing lymphoma from CT scans offers the alternative of substituting stereotaxic biopsy and neuropathological diagnosis for the more aggressive open surgical approach, since radiation therapy and possibly chemotherapy usually prove to be the treatment of choice.

Adolescent↗
PubMed1985

[Lateral lumbar disk hernia].

Eleven cases are reported of lateral lumbar herniated disc, an anatomical form presenting fairly atypical features and of relatively recent discovery. The patients presented with a highly painful single root lesion usually affecting L4 and L5 roots. Saccoradiculography was negative in almost all cases whereas computed tomography imaging allowed easy diagnosis of a lateral herniated disc, and demonstrated its foraminal or extraforaminal site. An appropriate surgical approach was thus possible, extremely lateral forms requiring an extraisthmian approach.

Humans↗
PubMed1984

Bronchoalveolar lavage in asthma: the effect of disodium cromoglycate (cromolyn) on leukocyte counts, immunoglobulins, and complement.

In a double-blind, placebo-controlled study, we measured the effect of disodium cromoglycate (DSCG) on leukocyte counts, total IgE, IgG, IgA, IgM, house dust mite-specific IgE, C3, and C4 in bronchoalveolar lavage (BAL) fluid and peripheral blood in 36 atopic, perennial asthmatic subjects (DSCG 19; placebo 17). Differential cell counts on bronchial mucus were also performed. The percentage of eosinophils in bronchial mucus and BAL fluid was significantly less after DSCG. There was also a significant decrease in the concentration of total IgA (expressed as an IgA/albumin ratio) in BAL fluid after a 28-day treatment with DSCG. When the DSCG-treated patients were divided into responders and nonresponders on the basis of average daily symptom scores, the responders had significantly less bronchial mucus eosinophils, BAL eosinophils, and house dust mite-specific IgE (but not IgA) after DSCG. No significant differences in any of the measurements were observed in the nonresponders or the placebo group similarly subdivided on the basis of symptom scores. These results suggest that the efficacy of DSCG in bronchial asthma might be related to its ability to suppress the local accumulation of eosinophils and specific-IgE antibodies.

Adolescent↗
PubMed1984

The spectrum of right bundle branch block as manifested in electrocardiographic body surface potential maps.

A wide spectrum of types of right bundle branch block (RBBB) were studied utilizing the body surface potential maps (BSPMs) of 37 children. Although the spectrum varied from very advanced RBBB to minimal partial RBBB, a common diagnostic feature was the absence of evidence for right ventricular breakthrough in the maps of all patients. Evidence for left ventricular breakthrough was usually seen, the exceptions being five patients with partial RBBB and one of 29 with advanced RBBB. The appearance of evidence for activation of the right ventricle by way of the septum was late in onset. In addition, especially in advanced RBBB, the BSPM pattern reflecting right ventricular activation was prolonged in such a manner that it appeared that utilization of right ventricular Purkinje tissue was minimal and inefficient. The BSPMs during ST-T, which were of inverse polarity, reflect repolarization that is determined by the sequence of depolarization to a greater degree than in the normal. In general, the more extensive the surgery, the more advanced the RBBB (as reflected in the BSPM), although there were exceptions. The one parameter that linked all patients with RBBB together was the absence of evidence for right ventricular epicardial breakthrough.

Adolescent↗
PubMed1982

Follicle-stimulating hormone. IV. Study of the histology of pubertal cryptorchid and scrotal testes in relation to the secretion of gonadotropins.

The morphologic characteristics of 85 cryptorchid and 63 contralateral (scrotal) testes showing histologic changes of puberty were studied. Spermatogenesis was not only delayed on the cryptorchid side but also hypocellular in all cases. The scrotal testes appeared hypocellular in 82.5% of the cases. Repetitive biopsies, performed in 12 patients, showed no improvement of cellularity after orchidopexy but progress in pubertal maturation. In the 22 boys submitted to luteinizing hormone-releasing hormone (LH-RH) stimulation, luteinizing hormone (LH) baseline values did not change significantly whereas follicle-stimulating hormone (FSH) baseline levels increased with advancing age and histologic stage of maturation. LH responses increased with the stage of maturation (without statistical significance); however, LH responses were significantly higher in the group without germ cells. FSH responses to LH-RH stimulation were consistently and significantly higher with advancing stages of maturation and in the group without cells.

Adolescent↗