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Biomedical subjects

E Cabrera

Publications and source records attributed to E Cabrera.

At least 37 records · Page 2Linked to original sources
PubMed1996

t(1;5)(q23;q33) in a patient with high-risk B-lineage acute lymphoblastic leukemia.

The t(1;5)(q23;q33) is a rare genetic anomaly that was reported previously in two infants with a myeloproliferative disorder and eosinophilia and in one adult patient with acute nonlymphocytic leukemia (ANLL). A 13-year-old boy with high-risk early pre-B acute lymphoblastic leukemia (ALL) who presented to our institution carried the t(1;5)(q23;q33). He had an initial blast count of 230 X 10(9)/L and responded poorly to prednisone. Complete remission (CR) was achieved, and he had a bone marrow (BM) relapse 3 months after despite intensive consolidation therapy. He underwent allogeneic BM transplantation (BMT) from a human leukocyte antigen (HLA)-identical siblings in early relapse with total body irradiation (TBI) and cyclophosphamide conditioning. He had a short second CR with a central nervous system (CNS) relapse on day + 106 after BMT. Two of the previously reported patients also did not respond to chemotherapy. The t(1;5)(q23;q33) appears to be a rare lineage nonspecific anomaly related to hematologic malignancies that are resistant to current therapy.

Adolescent↗
PubMed1996

Toddlers' speech and cognitive effort.

Two-year-olds were videotaped while engaged in free play and problem-solving play. The periods in which they were actively manipulating objects were analyzed as to level of engagement, distinguishing between periods of intense engagement, in which the children were concentrating on the nonverbal activity, and periods of casual engagement, in which they conducted the nonverbal activity in a more leisurely fashion. A micro-analysis of the children's spontaneous speech revealed that they spoke less at moments of intense engagement than at moments of casual engagement. These and other findings are taken as support for the hypothesis that when toddlers invest cognitive effort in nonverbal behavior, there is a reduction in mental resources available for speech.

Attention↗
PubMed1996

Growth enhancement in transgenic tilapia by ectopic expression of tilapia growth hormone.

The generation of transgenic fish with the transfer of growth hormone (GH) genes has opened new possibilities for the manipulation of growth in economically important fish species. The tilapia growth hormone (tiGH) cDNA was linked to the human cytomegalovirus (CMV) enhancer-promoter and used to generate transgenic tilapia by microinjection into one-cell embryos. Five transgenic tilapia were obtained from 40 injected embryos. A transgenic animal containing one copy of the transgene per cell was selected to establish a transgenic line. The transgene was stably transmitted to F1 and F2 generations in a Mendelian fashion. Ectopic, low-level expression of tiGH was detected in gonad and muscle cells of F1 transgenic tilapia by immunohystochemical analysis of tissue sections. Nine-month-old transgenic F1 progeny were 82% larger than nontransgenic fish at p = .001. These results showed that low-level ectopic expression of tiGH resulted in a growth acceleration in transgenic tilapia. Tilapia GH gene transfer is an alternative for growth acceleration in tilapia.

Animals↗
PubMed1995

Gibberellin biosynthesis in gib mutants of Gibberella fujikuroi.

The Ascomycete Gibberella fujikuroi synthesizes gibberellins, fujenal, carotenoids, and other terpenoids. Twelve gib mutants, isolated through the modified gibberellin fluorescence of their culture media, were subjected to chemical and biochemical analyses. Two mutants were specifically defective in the hydroxylation of carbon 13; their total gibberellin production was normal, but their main gibberellin was GA7 instead of GA3. Four mutants were blocked in the early reactions between geranylgeranyl pyrophosphate and 7-hydroxy-kaurenoic acid; two of them could not synthesize kaurene and another one was blocked in several oxidative steps. Six mutants had partial defects in early reactions, leading to the production of one-fifth to one-third of the wild type amounts of gibberellins and fujenal. Two of these produced considerable amounts of kaurenolides due to a defect in the conversion of kaurenoic acid to 7-hydroxykaurenoic acid. Another one produced no carotenoids, but attempts to isolate mutants of reactions shared by the carotenoid and gibberellin pathways failed. The gib mutations did not modify the ability of the fungus to live as a saprophyte.

Gibberella↗
PubMed1995

Dermatoglyphics in insulin-dependent diabetic patients with limited joint mobility.

Hand and palm dermatoglyphics were studied in 158 insulin-dependent diabetic children and adolescents [85 with limited joint mobility (LJM) and 73 without]. The findings in this group were compared with those in 400 control subjects, with a similar racial distribution. The main dermatoglyphics alterations found in diabetic patients with LJM, as compared with non-LJM diabetic patients and controls, may be summarized as follows: (a) decrease in digital total ridges count (TRC); (b) higher frequency in the number of arches; (c) decrease in the sum of a line and cubital loops, particularly in the women; (d) increase in the number of t'-axial triradii. These alterations suggest a genetic aetiology of this complication. Further studies are recommended in order to provide more insight into the origin of this disorder.

Adolescent↗
PubMed1993

Molecular analysis of a microaerobically induced operon required for hydrogenase synthesis in Rhizobium leguminosarum biovar viciae.

The nucleotide sequence (6138 bp) of a microaerobically inducible region (hupV/VI) from the Rhizobium leguminosarum bv. viciae hydrogenase gene cluster has been determined. Six genes, arranged as a single operon, were identified, and designated hypA, B, F, C, D and E based on the sequence similarities of all of them, except hypF, to genes from the hydrogenase pleiotropic operon (hyp) from Escherichia coli. The gene products from hypBFCDE were identified by in vivo expression analysis in E. coli, and their molecular sizes were consistent with those predicted from the nucleotide sequence. Transposon Tn5 insertions into hypB, hypF, hypD and hypE resulted in R. leguminosarum mutants that lacked any hydrogenase activity in symbiosis with peas, but still were able to synthesize the polypeptide for the hydrogenase large subunit. The gene products HypA, HypB, HypF and HypD contained CX2C motifs characteristic of metal-binding proteins. In addition, HypB bore a long histidine-rich stretch of amino acids near the N-terminus, suggesting a possible role in nickel binding for this protein. The gene product HypF, which was translationally coupled to HypB, presented two cysteine motifs (CX2CX18CX2C) with a capacity to form zinc finger-like structures in the N-terminal third of the protein. A role in nickel metabolism in relation to hydrogenase synthesis is postulated for proteins HypB and HypF.

Aerobiosis↗
PubMed1990

Isolation of the replication DNA region from a Rhizobium plasmid and examination of its potential as a replicon for Rhizobiaceae cloning vectors.

The DNA region essential for replication and stability of a native plasmid (pTM5) from Rhizobium sp. (Hedysarum) has been identified and isolated within a 5.4-kb PstI restriction fragment. The isolation of this region was accomplished by cloning endonuclease-restricted pTM5 DNA into a ColE1-type replicon and selecting the recombinant plasmids containing the pTM5 replicator (pTM5 derivative plasmids) by their ability to replicate in Rhizobium. DNA homology studies revealed that pTM5-like replicons are present in cryptic plasmids from some Rhizobium sp. (Hedysarum) strains but not in plasmids from strains of other Rhizobium species or Agrobacterium tumefaciens. The pTM5 derivative plasmids were able to replicate in Escherichia coli and A. tumefaciens and in a wide range of Rhizobium species. On the basis of stability assays in the absence of antibiotic selective pressure, the pTM5 derivative plasmids were shown to be highly stable in both free-living and symbiotic cells of Rhizobium sp. (Hedysarum). The stability of these plasmids in other species of Rhizobium and in A. tumefaciens varied depending on the host and on the plasmid. Most pTM5 derivative plasmids tested showed significantly higher symbiotic stability than RK2 derivative plasmids pRK290 and pAL618 in Rhizobium sp. (Hedysarum), R. meliloti, and R. leguminosarum by. phaseoli. Consequently, we consider that the constructed pTM5 derivative plasmids are potentially useful as cloning vectors for Rhizobiaceae.

Cloning, Molecular↗
PubMed1990

Effects of muscarinic and beta-adrenergic blockade on the aortic elastic response to epinephrine induced acute hypertension in conscious dogs.

To determine the effects of parasympathetic blockade and beta-blockade on the elastic response of aortic stiffness to vasopressive interventions, we studied 5 unanesthetised adult mongrel dogs by means of a pressure microtransducer and two ultrasonic crystals positioned at opposing sites in the proximal descending thoracic aorta which were used for diameter measurements. Systolic and diastolic changes in pressure and diameter were used to calculate Peterson and incremental elastic moduli. Acute hypertension was induced using infusions of epinephrine during the control period and later propranolol (1.5 mg/kg) plus atropine (0.2 mg/kg). Percent variations of mean aortic diameter were correlated to percent variations in mean aortic pressure in the control period and after autonomic blockade (P less than .001). The slopes of these correlations in the control group were higher than after autonomic blockade (P less than .05). Correlations were also found between Peterson and incremental elastic moduli and mean pressure in the control group and after autonomic blockade (P less than .001). The slopes of the correlations of incremental elastic modulus and Peterson's modulus versus mean aortic pressure were lower in the control group than after blockade (P less than .001). We conclude that in conscious dogs, autonomic blockade with propranolol and atropine decreased the distension and increased the stiffness of the aortic wall in response to acute hypertension mediated by epinephrine.

Acute Disease↗
PubMed1989

Monoclonal islet cell surface antibody dependent cellular cytotoxicity mediated by rat splenocytes with the RIN cell line as target.

A new method is described for testing monoclonal islet cell surface antibodies for their ability to mediate cellular immune effector mechanisms (ADCC). For the first time an IgM mediated cellular cytotoxicity is demonstrated. By using the RIN cell line as target the method was reproducible and easy to perform. The significance of such definition of monoclonal ICSA's to experimental diabetes research is discussed.

Animals↗
PubMed1989

[Visco-elastic characteristics of the aorta in conscious dogs in a model of experimental calcinosis].

Effects of experimental calcinosis induced by daily overdose of 500.000 IU Vit D3 during 10 days were studied in 6 mongrel conscious dogs chronically instrumented with intra-aortic Konigsberg microtransducer and two ultrasonic piezo-electric crystals diametrically opposed in the adventitia of the descending thoracic aorta. Simultaneous recording of instantaneous aortic pressure and diameter waves in basal state and during transient acute hypertension induced by intravenous angiotensin bolus (0.1 microgram/kg) allowed to obtain the pressure (y) diameter (x) relationship of the aorta according to an exponential regression: P = expo (beta D + A), with a highly significant correlation coefficient in all animals (r greater than 0.99). (table; see text) Anatomopathological studies of aortas revealed abnormal calcium deposition, ruptures of elastic fibers and disorganization of collagen. Thus, a striking decrease in aortic rigidity is observed after calcinosis in relation with structural changes of elastic materials and responsible in part for a reduction in pulsatile pressure; moreover this unexpected phenomena might represent an initiative process of development of aortic aneurysms.

Animals↗
PubMed1988

Aortic pulsatile pressure and diameter response to intravenous perfusions of angiotensin, norepinephrine, and epinephrine in conscious dogs.

The aortic elastic behavior has been studied in conscious dogs chronically instrumented with a pressure microtransducer and two ultrasonic crystals. Pressure and diameter measurements were analyzed in terms of their mean values and systolic-diastolic variations, enabling calculation of Peterson elastic modulus, and were displayed in the x-y form to obtain pressure diameter hysteresis loops. After recovery from surgery and under autonomic blockade, intravenous perfusions of angiotensin, norepinephrine, and epinephrine were made at incremental steps of doses until steady-state pressure-diameter changes were achieved. The slopes of the positive pressure-diameter correlations obtained at each dose of the same vasoactive substance were higher for angiotensin than norepinephrine (p less than 0.01) and epinephrine (p less than 0.001) and were higher for norepinephrine than epinephrine (p less than 0.05). Similarly, the slopes of the elastic modulus to mean pressure relation were significantly lower for angiotensin than for norepinephrine (p less than 0.05) and epinephrine (p less than 0.001) and were significantly lower for norepinephrine than epinephrine (p less than 0.001). Thus, at the same transmural pressure, the distension and stiffness of the aorta were lower and higher with epinephrine than with norepinephrine, respectively, and with norepinephrine than with angiotensin suggesting different potencies of these drugs in terms of smooth muscle activation in the aorta.

Angiotensin II↗
PubMed1988

Diversity of Plasmid Profiles and Conservation of Symbiotic Nitrogen Fixation Genes in Newly Isolated Rhizobium Strains Nodulating Sulla (Hedysarum coronarium L.).

Forty-five Rhizobium strains nodulating sulla (Hedysarum coronarium L.), isolated from plants grown in different sites in Menorca Island and southern Spain, were examined for plasmid content and the location and organization of nif (nitrogen fixation) and nod (nodulation) sequences. A great diversity in both number and size of the plasmids was observed in this native population of strains, which could be distributed among 19 different groups according to their plasmid profiles. No correlation was found between plasmid profile and geographical origin of the strains. In each strain a single plasmid ranging from 187 to 349 megadaltons hybridized to Rhizobium meliloti nifHD and nodD DNA, and in three strains the spontaneous loss of this plasmid resulted in the loss of the nodulation capacity. In addition to the symbiotic plasmid, 18 different cryptic plasmids were identified. A characteristic cryptic plasmid of >1,000 megadaltons was present in all strains. Total DNA hybridization experiments, with nifHD and portions of nodC and nodD genes (coding for common nodulation functions) from R. meliloti as probes, demonstrated that both the sequence and organization of nif and common nod genes were highly conserved within rhizobia nodulating sulla. Evidence for reiteration of nodD sequences and for linkage of nodC to at least one copy of nodD was obtained for all the strains examined. From these results we conclude that Rhizobium strains nodulating sulla are a homogeneous group of symbiotic bacteria that are closely related to the classical fast-growing group of rhizobia.

Journal Article↗
PubMed1988

Constricting and stiffening action of atropine on aortic response to angiotensin in dogs.

The elasticity of the thoracic aorta was studied in nine dogs instrumented with a pressure microtransducer and two ultrasonic crystals diametrically fixed in the adventitia. Systolic and diastolic changes in pressure and diameter were used to calculate Peterson and incremental elastic moduli. Acute hypertension was induced by infusions of angiotensin performed 1) during the control period, 2) after propranolol (1.5 mg/kg), 3) after atropine (0.2 mg/kg), and 4) after propranolol plus atropine. Absolute and percent variations of mean diameter were correlated to pressure in the control period and after autonomic blockade (p less than 0.01). The slopes of these correlations were not different between propranolol and control groups, but were lower with atropine (p less than 0.01) and with atropine plus propranolol (p less than 0.001) than in the control period. Correlations were also found between Peterson and incremental elastic moduli and mean pressure in the control period and after blockade (p less than 0.001). No differences of slopes existed between propranolol and control groups, but the slope of the correlation relative to the incremental elastic modulus was higher with atropine than in the control period (p less than 0.05), and the slopes of the correlations relative to the Peterson and the incremental elastic moduli were respectively higher with atropine plus propranolol than in the control period (p less than 0.05, p less than 0.05). Thus, atropine decreased the distention and increased the stiffness of the aorta in response to acute angiotensin-mediated hypertension.

Angiotensin II↗
PubMed1988

[Constrictive and stiffening effects of parasympathetic blockade on the pressure response of the aorta to angiotensin in the conscious dog ].

The elastic response of the thoracic aorta to increasing steps of angiotensin was studied in chronic instrumented conscious dogs with and without parasympathetic blockade by atropine. A pressure microtransducer and two ultrasonic crystals diametrically opposed and fixed in the adventitia enabled to determine the mean and systolic-diastolic changes of pressure (P) and diameter (D). By computing these measurements two representative indexes of dynamic elastic modulus in vivo were calculated; the elastic modulus of Peterson (Ep) Ep = delta P/D.D and the incremental elastic modulus (Ei) Ei = 0.75 EP/gamma, gamma being the ratio of the thickness to the external radius. A positive correlation (p less than 0.01) was obtained between pressure and diameter variations in the presence or absence of atropine but the slope of these relationship were lower with atropine than in controls. The slope of the positive correlations observed between Peterson and incremental elastic modulus and the increase in mean arterial pressure in response to angiotensin (p less than 0.01) was higher in the presence of atropine (p less than 0.05). These observations indicate that in response to angiotensin mediated high blood pressure, the cholinergic blockade of muscarinic receptors with atropine induce a contraction and increasing rigidity of the aorta.

Angiotensin II↗
PubMed1987

Cyclosporine therapy and refractory Pneumocystis carinii pneumonia. A potential association.

In surveillance of 75 patients receiving renal transplants in 1984 at our institution, five cases of Pneumocystis carinii pneumonia were detected. All five cases occurred in a subgroup of 11 patients who had received cyclosporine. A retrospective epidemiologic survey of the infected patients revealed all five were heterosexual white men with onset of Pneumocystis pneumonia two to six months after cadaveric transplantation. All received cyclosporine and corticosteroids, and four of five patients also received azathioprine; none was neutropenic or had evidence of concurrent cytomegalovirus infection. Only one of these patients responded to therapy with sulfamethoxazole and trimethoprim, one patient responded to pentamidine therapy, and the remaining three patients died. Cyclosporine use may be related to development of Pneumocystis infections that are refractory to conventional antiprotozoal therapy, and transplantation programs should closely survey patients for such complications.

Adult↗
PubMed1987

[Study of the visco-elastic response of the aortic wall to angiotensin and noradrenaline in the conscious dog by analysis of the instantaneous pressure-diameter relation in the descending aorta].

The viscoelastic behaviour of the aorta has been studied in 7 adult non-anesthesized mongrel dogs, chronically instrumented with a microtransducer pressure (Konigsberg P7) implanted inside the aortic lumen, and 2 ultrasonic crystals diametrically opposed and fixed in the adventitia of the thoracic aorta. Pressure and diameter were analysed in terms of mean values and of systolic diastolic variations, enabling to calculate the elastic modulus of Peterson. After recovery from surgery, and under autonomic blockade by atropine and propranolol, perfusions of angiotensin and norepinephrine were performed at incremental steps of doses. In individual dogs, instantaneous pressure-diameter relationships were formed by the different pressure diameter hysteris loops obtained at each dose of the same drug; the relationships obtained with the two drugs were curvilinear and were mixed at lower pressure ranges, but at highest levels of pressures it was found, that comparatively to angiotensin curve, that of norepinephrine had shifted toward lower diameter. The percent increase in mean diameter from baseline obtained at each dose of the same drug, was positively correlated to the corresponding per cent increase in mean pressure, with angiotensin (r = 0.83 P less than 0.001), and for norepinephrine (r = 0.82 P less than 0.001), but the slope of the relation was lower with angiotensin (22.3 +/- 3.2) than with norepinephrine (12.8 +/- 1.9) (P less than 0.001); likewise, the elastic modulus, for each dose of a same drug, was positively correlated to the corresponding mean pressure for angiotensin (r = 0.53 P less than 0.01), norepinephrine (r = 0.69 P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1986

Pharmacokinetics of the combination of ticarcillin with clavulanic acid in renal insufficiency.

The pharmacokinetics of ticarcillin and clavulanic acid were studied by blood and urine assay methods in 25 patients divided into five groups with varying degrees of renal insufficiency i.e. mild, moderate and severe renal insufficiency, almost anuric patients and those requiring haemodialysis (groups A to E). A single dose of 5.2 g Timentin (5.0 g ticarcillin and 200 mg clavulanic acid) was administered intravenously by infusion over 30 min. The average elimination half-life (T1/2) of ticarcillin increased from 0.95 h in patients with creatinine clearance (Clcr) of 80 ml/min to 1.8, 4.4, 6.9 and 11.2 h respectively in mild, moderate and severe renal insufficiency and in almost anuric patients. The T1/2 values for clavulanic acid were 0.75, 0.9, 2.0, 2.5 and 4.8 h in the same groups. The area under concentration-time curve (AUC) for ticarcillin increased from 787 to 2839 mg/l/h and for clavulanic acid from 12.8 to 29 mg/l/h when group mean values from patients with mild and severe renal insufficiency were compared. The plasma clearance (Clpl) of clavulanic acid was in all groups greater than that of ticarcillin i.e. 166 and 100 ml/min vs. 79.2 and 25.0 ml/min when comparing mean values from groups with mild and severe renal insufficiency respectively. The plasma clearance ratio clavulanic acid/ticarcillin increased proportionally to the degree of renal insufficiency from a value of 1.5 in normal subjects to between 3.3 and 3.8 in more advanced cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗