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Biomedical subjects

I Diaz

Publications and source records attributed to I Diaz.

At least 19 recordsLinked to original sources
PubMed2006

Ternary complex formation between HvMYBS3 and other factors involved in transcriptional control in barley seeds.

The SHAQKYF R1MYB transcription factor (TF) HvMYBS3 from barley is an activator of gene expression both during endosperm development and in aleurone cells upon seed germination. Its mRNA was detected as early as 10 days after flowering in developing barley endosperm, with a peak at 18 days, and in aleurone cells at 8 h after water imbibition, as shown by Northern blot and in situ hybridization analyses. The HvMYBS3 protein expressed in bacteria binds to oligonucleotides containing a GATA core derived from the promoters of: (i) the developing endosperm gene Itr1 (5'-GATAAGATA-3') encoding trypsin inhibitor BTI-CMe, and (ii) the post-germinating aleurone gene Amy6.4 (5'-TATCCAC-3'/5'-GTGGATA-3') encoding a high-pI alpha-amylase. Transient expression experiments in co-bombarded developing endosperms and in barley aleurone layers demonstrated that HvMYBS3 trans-activated transcription both from Itr1 and Amy6.4 promoters, in contrast with a previously reported seed-expressed R1MYB, HvMCB1, which was an activator of Itr1 and a transcriptional repressor of the Amy6.4 gene. In the yeast three-hybrid system, the HvMYBS3 protein formed a ternary complex with BPBF and BLZ2, two important seed TFs. However, no binary interactions could be detected between HvMYBS3 and BLZ2 or between HvMYBS3 and BPBF.

Amino Acid Sequence↗
PubMed2006

Novel approach to control sulfamethazine misuse in food-producing animals by hair analysis.

The presence of sulfamethazine residues in pig and calf hair was compared with the residual levels encountered in the corresponding edible tissues (liver and muscle) as a consequence of drug administration. Sulfamethazine up to 84.7 mg kg-1 was found in calf hair samples after a pharmacological treatment, with a significant effect of hair pigmentation. High concentrations of the parent drug were detected in calf hair for 4 weeks after administration, when sulfamethazine residues were no longer detectable in the corresponding edible tissues. In a similar way, pig hair also accumulated sulfamethazine residues up to 40.5 mg kg-1, which was more than the amount detected in the corresponding muscle and liver samples at slaughter. Hair analysis seems a suitable tool to improve the efficacy of regulatory controls, and thus the safety of the food chain and to discourage the improper use of sulfamethazine in animal farming.

Animals↗
PubMed2006

Response surface methodology for the optimization of keratinase production in culture medium containing feathers produced by Kocuria rosea.

A 43-fold increase in keratinase production by Kocuria rosea was achieved in batch fermentation using response surface methodology. Factorial designs were used to select the components of a culture medium that showed a significant effect on keratinase production. An orthogonal-central composite experimental design was performed, with only two (feathers and magnesium) from nine initial compounds being further analyzed by response surface methodology. An optimum keratinase production of 14 886.9 U/mg was obtained with the following medium composition (per litre): NH4Cl, 0.3 g; NaCl, 0.3 g; K2HPO4, 3.2 g; KH2PO4, 4.0 g; MgSO4.6H2O, 0.5 g; yeast extract, 0.1 g; and finely milled feathers, 30 g. The medium was shaken at 400 r/min with an incubation period of 14 h at 40 degrees C.

Animals↗
PubMed2004

Extended coasting duration exerts a negative impact on IVF cycle outcome due to premature luteinization.

Coasting, or withholding gonadotrophin administration while maintaining gonadotrophin-releasing hormone analogue until oestradiol drops to a safe concentration, is an alternative approach to prevent ovarian hyperstimulation syndrome (OHSS) in high responder patients. However, the length of this procedure has not been precisely studied. This paper is a retrospective study of 132 patients who showed a high response (oestradiol > 4500 pg/ml and/or more than 20 follicles > 17 mm) to ovarian stimulation and were coasted due to their high risk of developing OHSS, and evaluated the impact of the duration of coasting on IVF cycle outcome. Additionally, serum LH and progesterone concentrations were studied to investigate whether premature luteinization was present in these cycles and whether it might be related to coasting duration. A significant decrease in implantation rate was found when coasting was required for more than 4 days, together with a trend towards a higher cancellation rate. Premature luteinization was significantly elevated in women undergoing coasting compared with control women (34 versus 15.6%, P < 0.05). In the majority of patients who showed premature luteinization, coasting lasted >/=3 days. To conclude, prolonged coasting may affect the endometrium, anticipating the implantation window. These data may explain why some women undergoing extended coasting show a lower implantation rate compared with controls.

Adult↗
PubMed2003

Splanchnic perfusion during delayed, hypotensive, or aggressive fluid resuscitation from uncontrolled hemorrhage.

The purpose of this study was to determine the effect of three different fluid resuscitation strategies on splanchnic perfusion in a clinically relevant model of uncontrolled hemorrhage after liver trauma. Anesthetized swine were instrumented with a gastric near-infrared spectroscopy probe (GStO2), a jejunal tonometer (PrCO2), a portal vein catheter (SpvO2, lactate), and an ultrasonic blood flow probe on the superior mesenteric artery. The liver was lacerated to produce uncontrolled hemorrhage and a shock state characterized by a 40-60% decrease in cardiac output and a decrease in mean arterial pressure (MAP) to 42 +/- 1 mmHg. Animals were randomly assigned to either delayed resuscitation (n = 6); hypotensive resuscitation with lactated Ringer's infusion to MAP = 60 mmHg (n = 6); or aggressive resuscitation with LR to MAP >/= 75 mmHg (n = 6). For the remainder of the protocol, the treatment was identical. The data showed that blood loss (47 +/- 7 and 45 +/- 10 mL/kg) and total fluid requirements (118 +/- 73 and 171 +/- 85 mL/kg) were similar with either hypotensive or aggressive resuscitation. In contrast, with delayed resuscitation, both values were lower (27 +/- 2 mL/kg and 87 +/- 33 mL/kg, both P < 0.05). Despite aggressive resuscitation, SpvO2 and GstO2 were about 10% lower (both P < 0.05 within group) and PrCO2 was about 20 mmHg higher (P < 0.05 within group) than the corresponding values in the other two groups. Thus, delayed resuscitation minimized the blood loss but did not restore tissue oxygenation, whereas aggressive resuscitation was associated with maximal blood loss and splanchnic hypoperfusion. For this reason, it is reasonable to conclude that hypotensive resuscitation might be an effective strategy to maintain splanchnic perfusion after blunt abdominal trauma and uncontrolled hemorrhage.

Acid-Base Equilibrium↗
PubMed2001

Experimental study of bone response to a new surface treatment of endosseous titanium implants.

This study examines a new surface treatment that uses coarse calcium phosphate, which provides the benefits of surface roughening without introducing any foreign materials that may become imbedded in the implants. It is intended to enhance the use of implants in areas of inferior bone quality and quantity, such as the posterior areas of the maxilla and the mandible. Implants placed in the tibia of rabbits were removed after 16 weeks and examined microscopically. Pore sizes examined under the scanning electron microscope met the conditions described in the literature for successful integration. Optic microscopy revealed evidence of bone apposition over the roughened implant surface comparable to that seen in other surfaces. There was a definite absence of fibrous tissue, demonstrating good-to-excellent bone contact with the Restore Resorbable Blast Media implants (Lifecore Biomedical, Chaska, MN). In addition, it appears that the blasting of resorbable calcium phosphate on the machine titanium surface results in the resorbable blast media surface acting like an inert material. Further studies with a larger sample size are needed to confirm these initial findings.

Animals↗
PubMed2000

Adaptation of Spodoptera exigua (Lepidoptera: Noctuidae) to barley trypsin inhibitor BTI-CMe expressed in transgenic tobacco.

Nicotiana tabacum plants were transformed with the cDNA of barley trypsin inhibitor BTI-CMe under the control of the 35S CaMV promoter. Although the transgene was expressed and the protein was active in the homozygous lines selected, growth of Spodoptera exigua (Lepidoptera: Noctuidae) larvae reared on transgenic plants was not affected. The protease activity in larval midgut extracts after 2 days feeding on transformed tobacco leaves from the highest expressing plant showed a reduction of 25% in the trypsin-like activity compared to that from insects fed on non-transformed controls. The susceptibility of digestive serine-proteases to inhibition by BTI-CMe was confirmed by activity staining gels. This decrease was compensated with a significant induction of leucine aminopeptidase-like and carboxipeptidase A-like activities, while chymotrypsin-, elastase-, and carboxipeptidase B-like proteases were not affected.

Adaptation, Physiological↗
PubMed2000

Intra- and inter-individual variability in human sperm concentration, motility and vitality assessment during a workshop involving ten laboratories.

The aim of the present study was to assess variability in the evaluation of human sperm concentration, motility and vitality. Technicians and biologists from 10 teams involved in multicentre studies on semen quality attended the same laboratory, each team using its own methods and equipment to analyse the same semen samples. Inter-individual variability was assessed from 17 fresh semen samples of varying quality. Intra-individual variability was assessed from pools of frozen samples for sperm concentration and motility and stained smears for vitality with three blind evaluations by sample and smear. The mean inter-individual coefficients of variation were 22.9, 21.8 and 17.5% for sperm concentration, motility and vitality respectively. There was no statistical difference among participants for sperm concentration assessment, but significant differences for both motility and vitality (both P: < 0.05). The mean intra-individual coefficients of variation were 15.8, 26.2 and 13.1% for sperm concentration, motility and vitality respectively, with marked differences between expert and novice participants: concentration 9.8% versus 28.0%; motility 22.8% versus 33.0%; and vitality 10.0% versus 19.3%. The present data confirm the need for external quality control schemes for diagnostic purposes, and indicate their utmost importance in multicentre studies on semen quality.

Cell Survival↗
PubMed2000

[Intestinal parasites in school children at a public institution in Maracaibo municipality, Venezuela].

To determine the prevalence and epidemiological parameters of intestinal parasites in schoolchildren, a faecal analysis was performed in 349 individuals of both sexes, between 5 and 16 years of age. The methodology used included, a fresh test, formol-ether technique and faecal egg counts by the Kato-Katz method. Eighty three per cent of the children presented enteroparasites, with a high prevalence of polyparasitism (71.6%). There was not significative difference between parasitoses, sex and age. However, it was observed an increase of helminthiasis and protozooses in children between 7 and 10 years of age. The principal enteroparasites founded were: Trichuris trichiura (41.8%), Ascaris lumbricoides (35.2%), Blastocystis hominis (48.1%) and Endolimax nana (22.9%). When the intensity of infestation was studied by the faecal egg counts, it was observed that the highest percentage of children with T. trichiura had light infestations (84.3%), while 45.9% of the children with A. lumbricoides had severe infestations. The Abundance, Mean Intensity and Aggregation Coefficient (k) values show an over-dispersed spatial disposition of both helminths, where only few children harbour heavy burdens and eliminate a large quantity of eggs. This aggregation was higher for T. trichiura (k = 0.298) than for A. lumbricoides (k = 1.138).

Adolescent↗
PubMed1999

Staghorn calculi in children: treatment with monotherapy extracorporeal shock wave lithotripsy.

PURPOSE: We evaluated the effectiveness of monotherapy extracorporeal shock wave lithotripsy (ESWLT) for treating children with staghorn calculi. MATERIALS AND METHODS: From February 1992 to December 1997, 11 boys and 4 girls 14 months to 13 years old (median age 4 years) presented to our institution with staghorn calculi. In these patients ESWL was performed using a Siemens Lithostar-ULTRA with ultrasound stone localization and with intravenous sedation or without anesthesia. Using the Puigvert method the frequency and energy of the shock waves delivered were increased progressively to desensitize cutaneous nerve receptors, making the procedure less painful and improving stone fragmentation. RESULTS: Overall stones resolved in 11 of the 15 patients (73.3%) after an average of 2 ESWL sessions. Of the 11 patients 7 were stone-free after only 1 session, 2 with fragments less than 5 mm. required no further intervention, and 2 required additional surgery, including percutaneous nephrolithotomy to remove large residual stone fragments in 1 and open renal surgery to remove a cystine staghorn calculus in 1. Ureteral stents were not required in any patients. One case of post-ESWL fever resolved promptly with antibiotics. CONCLUSIONS: ESWL using the Siemens Lithostar-ULTRA is simple, effective and safe primary treatment in children with staghorn calculi.

Adolescent↗
PubMed1998

Barley BLZ1: a bZIP transcriptional activator that interacts with endosperm-specific gene promoters.

A cDNA encoding a bZIP transcription factor was obtained from barley endosperm and used to identify the corresponding gene from a genomic library. The gene, designated Blz1, contained six exons and five introns, plus a 442 nt-long 5'-untranslated leader sequence, and was located on chromosome 5H. The Blz1 mRNA was detected early in endosperm development and was also expressed in roots and leaves. The BLZ1 protein was a potent transcriptional activator in a yeast system; 85% of its activity was associated with the first 203 amino acid residues at the N-terminus, which included two acidic regions. Presumptive involvement of Blz1 in the regulation of gene expression in endosperm was ascertained by the DNA-binding properties of BLZ1 in electrophoretic mobility shift assays (EMSA) and by transient expression in barley developing endosperms, using, as effectors, Blz1 in both sense and anti-sense orientations. In the co-bombardment experiments, the beta-glucuronidase (GUS) reported gene responded to Blz1 if under the control of the endosperm-specific ltr1 promoter or under a synthetic promoter containing the endosperm box of gene Hor2. Sucrose synthase promoters Ss1 and Ss2 and synthetic promoters containing mutated sequences of Hor2 were unaffected in trans by Blz1.

Amino Acid Sequence↗
PubMed1997

[Physiology of human gamete interaction].

Subzonal insemination was the first micromanipulation technique used in the treatment of male factor sterility. Analysis of the sperm pathology prior to patient inclusion in the program allowed us to study gamete interaction in the human and the early embryogenesis. A series of 523 cycles and 3,027 micro-injected oocytes is reported.

Animals↗
PubMed1996

Two cold-inducible genes encoding lipid transfer protein LTP4 from barley show differential responses to bacterial pathogens.

The barley genes HvLtp4.2 and HvLtp4.3 both encode the lipid transfer protein LTP4 and are less than 1 kb apart in tail-to-tail orientation. They differ in their non-coding regions from each other and from the gene corresponding to a previously reported Ltp4 cDNA (now Ltp4.1). Southern blot analysis indicated the existence of three or more Ltp4 genes per haploid genome and showed considerable polymorphism among barley cultivars. We have investigated the transient expression of genes HvLtp4.2 and HvLtp4.3 following transformation by particle bombardment, using promoter fusions to the beta-glucuronidase reporter sequence. In leaves, activities of the two promoters were of the same order as those of the sucrose synthase (Ss1) and cauliflower mosaic virus 35S promoters used as controls. Their expression patterns were similar, except that Ltp4.2 was more active than Ltp4.3 in endosperm, and Ltp4.3 was active in roots, while Ltp4.2 was not. The promoters of both genes were induced by low temperature, both in winter and spring barley cultivars. Northern blot analysis, using the Ltp4-specific probe, indicated that Xanthomonas campestris pv. translucens induced an increase over basal levels of Ltp4 mRNA, while Pseudomonas syringae pv. japonica caused a decrease. The Ltp4.3-Gus promoter fusion also responded in opposite ways to these two compatible bacterial pathogens, whereas the Ltp4.2-Gus construction did not respond to infection.

Antigens, Plant↗
PubMed1996

Isolation and promoter characterization of barley gene Itr1 encoding trypsin inhibitor BTI-CMe: differential activity in wild-type and mutant lys3a endosperm.

The gene Itr1, encoding trypsin inhibitor BTI-CMe, has been obtained from a genomic library of Hordeum vulgare L. The gene has no introns and presents in its 5'-upstream region 605 bp that are homologous to the long terminal repeats (LTR) of the 'copia-like' retro-transposon Bare-1. Functional analysis of the Itr1 promoter by transient expression in protoplasts derived from different barley tissues, has shown that in this system the Itr1 promoter retains its endosperm specifity and the trans-regulation mediated by the Lys3a gene. The proximal promoter extending 343 bp upstream of the translation initiation ATG codon is sufficient to confer full GUS expression and for endosperm specifity. In protoplasts derived from the lys3a mutant, Risø 1508, GUS activity was less than 5% of that obtained with the same constructs in the protoplasts of wild-type Bomi from which it derives. Gel retardation experiments, after incubation with proteins obtained from both types of endosperm nuclei, also show differential patterns. Possible reasons for these differences are discussed.

Amino Acid Sequence↗
PubMed1996

DNA ploidy study of resected hepatocellular carcinoma in cirrhotic liver.

BACKGROUND/AIMS: Results of several studies on DNA ploidy as a prognostic indicator in hepatocellular carcinoma are contradictory. The present study analysed the correlations between DNA ploidy of resected hepatocellular carcinoma and tumour characteristics, tumour recurrence, risk factors and survival. METHODS: Tumoural DNA ploidy of hepatocellular carcinomas from 37 patients with cirrhosis who underwent curative tumour resection was studied by flow cytometry. RESULTS: A diploid pattern was found in 23 hepatocellular carcinomas (62.2%) and an aneuploid pattern in 14 (37.8%). The tumour recurrence rate did not differ statistically between diploid (69.6%) and aneuploid (50%) hepatocellular carcinomas. The only prognostic variable with significant difference in DNA pattern was the histologic tumour type; the majority of non-trabecular tumours were aneuploid while most trabecular hepatocellular carcinomas had a diploid DNA pattern. Actuarial survival at 1, 2, 3 and 4 years of patients with diploid and aneuploid tumours was 69.6%, 40.6%, 16.2% and 0%, and 69.3%, 59.4%, 49.5% and 32.9%, respectively (log rank p = 0.1927). CONCLUSION: These results indicate that DNA ploidy has no prognostic value in hepatocellular carcinoma.

Adult↗
PubMed1995

The promoter of the gene Itr1 from barley confers a different tissue specificity in transgenic tobacco.

Tissue-specific expression of the gene coding for trypsin inhibitor BTI-CMe in barley (Itr1) occurs during the first half of endosperm development. In transgenic tobacco, the Itr1 promoter drives expression of the beta-glucuronidase reporter gene not only in developing endosperm but also in embryo, cotyledons and the meristematic intercotyledonary zone of germinating seedlings. A promoter fragment extending 343 bp upstream of the translation initiation ATG codon was sufficient for full transgene expression, whereas, the proximal 83 bp segment of the promoter was inactive. Possible reasons for the differences in expression patterns are discussed.

Base Sequence↗
PubMed1995

Selective disulphide linkage of plant thionins with other proteins.

Thionins are shown to form disulphide linkages with other proteins. The reaction with bacterial enzymes beta-glucuronidase and neomycin phosphotransferase II could be prevented and reversed with dithiothreitol and blocked with N-ethylmaleimide. Other cysteine-rich low-molecular-weight toxic peptides from plants (LTP-3 from barley and P19 from potato) did not react as the thionins. Certain cysteine-containing proteins, such bovine serum albumin, ovalbumin and cytochrome c, reacted with thionins, while others, including carbonic anhydrase, soybean trypsin inhibitor, bovine-lung trypsin inhibitor and phosphorylase B did not. Selectivity of the reaction with a periplasmic component of the phytopathogenic bacterium Pseudomonas solanacearum was also shown.

Antimicrobial Cationic Peptides↗