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Biomedical subjects

J Hernandez

Publications and source records attributed to J Hernandez.

At least 55 records · Page 3Linked to original sources
PubMed2000

ESR and optical absorption studies of gamma- and electron-irradiated sugar crystals

Electron spin resonance (ESR) studies of the free radicals induced in gamma- or electron-irradiated sugar crystals were performed. The number of radicals increases linearly, pointing out that this material can be used as a dosimeter. The optical absorption studies show the presence of several distinctive bands in the infrared and UV region, whose intensity changes with the irradiation dose. An interpretation of these results in terms of the formation of free radicals and possible crosslinking along the sugar molecular chains is presented.

Journal Article↗
PubMed2000

Experimental studies of the liquid-glass transition in trimethylheptane

The molecular glass former trimethylheptane was studied by calorimetric, dielectric, ultrasonic, neutron scattering, Brillouin scattering, and depolarized light-scattering techniques. The molecular structure appears to be nearly spherical optically as indicated by the low depolarization ratio and dielectric susceptibility values. A preliminary mode-coupling theory (MCT) analysis of the light-scattering and neutron-scattering data indicates that T(C) greater, similar150 K, at least 25 K above T(G). The susceptibility minima were analyzed with the MCT interpolation equation, and disagreement between the light and neutron results was observed despite the apparent isotropy of the molecules.

Journal Article↗
PubMed2000

Milk urea nitrogen and infertility in Florida Holstein cows.

The objective of this study was to evaluate the association between milk urea nitrogen (MUN) and risk of nonpregnancy after first breeding in a commercial dairy herd in Florida. A total of 515 and 558 cows were classified as having high (17 to 25 mg/dl) or low MUN (6 to 16 mg/dl) within 30 d before first breeding; a total of 158 (30.6%) and 189 (33.8%) cows were diagnosed as pregnant, respectively. Logistic regression was used to evaluate the association between MUN and risk of nonpregnancy controlling for other variables associated with fertility (parity, calving season, breeding season). An interaction was found showing that cows with high MUN that were bred during the summer were 18 times (OR = 17.9; 95% CI = 10.0 to 31.7) at higher risk of nonpregnancy compared to cows with low MUN that were bred during the winter.

Animals↗
PubMed2000

Efficacy of two modified nonantibiotic formulations (Victory) for treatment of papillomatous digital dermatitis in dairy cows.

A field trial was conducted to compare the efficacy of the original and two modified formulations of Victory and oxytetracycline among dairy cows affected with papillomatous digital dermatitis. Seventy-eight cows with papillomatous digital dermatitis lesions were randomly allocated to one of four treatment groups (A, B, C, D). Cows in group A (n = 19) were treated with an oxytetracycline solution; cows in group B (n = 22) were treated with the original formulation of Victory containing soluble copper, peroxide compound, and a cationic agent; cows in group C (n = 17) were treated with a modified formulation of Victory containing reduced soluble copper and peroxide compound but increased levels of cationic agent; and cows in group D (n = 20) were treated with a modified formulation of Victory containing levels of soluble copper and cationic agent equivalent to the original formulation but with reduced concentrations of peroxide compound. Cows were examined 7, 14 and 28 d after initial treatment; during each examination, pain and lesion scores were recorded. The modified nonantibiotic formulation used in cows in group C appeared to be the most effective for treatment of papillomatous digital dermatitis. Proportions of cows with signs of pain were significantly lower among cows in group C, compared with cows in group A. Similarly, pain scores were significantly lower among cows in treatment group C, compared to cows in group A. The 2 low efficacy of oxytetracycline was an unexpected result b and may have clinical implications associated with possible antibiotic resistance in dairy cows affected with papillomatous digital dermatitis.

Animals↗
PubMed2000

Evaluation of two reverse transcription polymerase reaction assays (GEN ETI-K HGV RNA and LCx GBV-C assay) for the detection of GB virus C/hepatitis G virus RNA in clinical samples.

Our study evaluates the analytical performance of two amplification methods in the detection of GB Virus C/Hepatitis G Virus, GEN ETI-K HGV RNA (GEN) and the LCx GBV-C Assay (LCx). GB Virus C RNA was detected by at least one test in 58/315 samples (18.41%). Fifty-five samples (17.46%) were positive by the GEN method and 51 samples (16.19%) by the LCx method. The same rate of detection was found for 71 haemodialysis patients and 18 non-A non-E hepatitis. Method based differences in prevalence were observed for patient samples from the general population, 8/106 (7.55%) positive by GEN vs 7/106 (6.60%) by LCx; and HIV infected patients, 26/98 (26.53%) vs 23/98 (23.46%). For chronic type C hepatitis 10/22 (45.5%) were positive by both methods, with two samples discordant. Overall, discordance was observed for ten samples, with seven positive only by the GEN ETI-K HGV RNA, and three positive only by the LCx GBV-C Assay. An additional evaluation of serial samples, from chronic type C hepatitis patients under interferon treatment, revealed three samples which were positive only by the GEN method. Results were 100% concordant for patients under haemodialysis and for non-A non-E hepatitis, 95.9% in the HIV positive group, 90.9% in the chronic type C hepatitis group, and 97.1% in the general population group. Overall, a 97.2% of concordance was found between methods. Both tests have a similar diagnostic performance, though in our opinion, LCx GBV-C Assay better suits the requirements of a clinical microbiology diagnostic laboratory.

Flaviviridae↗
PubMed2000

[Report of a case of Acanthamoeba keratitis].

CLINICAL REPORT: A clinical report of a contact lenses wearer with Acanthamoeba keratitis pointed out the diagnosis problem. The medical treatment is needed previously to any surgery. Finally the patient underwent enucleation. DISCUSSION: The authors are considering the microbiological aspects and laboratory techniques are described. CONCLUSION: For this very severe but hopefully rare pathology, the sooner the treatment the best. A therapeutic approach is described.

Acanthamoeba Keratitis↗
PubMed1999

Effect of oral administration of a calcium chloride gel on blood mineral concentrations, parturient disorders, reproductive performance, and milk production of dairy cows with retained fetal membranes.

OBJECTIVE: To assess the effect of oral administration of CaCl2 gel on blood mineral concentrations, parturient disorders, reproductive performance, and milk production of dairy cows with retained fetal membranes (RFM). DESIGN: Randomized field trial. ANIMALS: 20 cows that calved normally and were not treated with CaCl2 gel (group 1), 20 cows with RFM that were treated with CaCl2 gel (group 2), and 20 cows with RFM that were not treated with CaCl2 gel (group 3). PROCEDURE: Group-2 cows were treated orally with CaCl2 gel (54 g of calcium) 24 and 48 hours after parturition. RESULTS: Administration of CaCl2 gel 24 and 48 hours after parturition did not have a significant effect on serum normalized calcium, total calcium, magnesium, or phosphorus concentrations or on incidence of metritis or left displacement of the abomasum, days to first insemination, pregnancy status after first insemination, or milk production. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of CaCl2 gel 24 and 48 hours after parturition did not have significant effect on blood mineral concentrations, parturient disorders, reproductive performance, and milk production in dairy cows with RFM.

Abomasum↗
PubMed1999

Comparison of topical application of oxytetracycline and four nonantibiotic solutions for treatment of papillomatous digital dermatitis in dairy cows.

OBJECTIVE: To compare efficacy of topical treatment with oxytetracycline solution or 1 of 4 nonantibiotic solutions among dairy cows with papillomatous digital dermatitis (PDD). DESIGN: Randomized field trial. ANIMALS: 66 cows in a single herd. PROCEDURE: Cows were randomly assigned to be treated with oxytetracycline solution; a commercial formulation of soluble copper, peroxide compound, and a cationic agent; 5% copper sulfate solution; acidified ionized copper solution; hydrogen peroxide-peroxyacetic acid solution; or tap water. Cows were examined 14 and 30 days after initial treatment. During each examination, pain and lesion scores were recorded. RESULTS: On the basis of pain and lesion scores, oxytetracycline and the commercial formulation appeared equally effective for treatment of PDD and significantly more effective than 5% copper sulfate solution, acidified ionized copper solution, hydrogen peroxide-peroxyacetic acid solution, and tap water. Proportions of cows with signs of pain or visible lesions after treatment were significantly lower for cows treated with oxytetracycline or the commercial formulation than for cows in the other groups. CLINICAL IMPLICATIONS: Oxytetracycline and a commercial formulation of soluble copper, peroxide compound, and a cationic agent appeared to be effective for treatment of PDD in dairy cows.

Administration, Topical↗
PubMed1999

Lack of Borrelia burgdorferi DNA in synovial samples from patients with antibiotic treatment-resistant Lyme arthritis.

OBJECTIVE: To determine whether Borrelia burgdorferi DNA may be detected in synovial tissue from patients with Lyme arthritis who have persistent synovial inflammation after antibiotic treatment. METHODS: Synovial specimens obtained at synovectomy from 26 patients with antibiotic treatment-resistant Lyme arthritis and from 10 control subjects were tested for B burgdorferi DNA using 3 primer-probe sets that target genes encoding outer surface proteins A or B or a flagellar protein (P41) of the spirochete. RESULTS: The 26 patients with Lyme arthritis, who had received antibiotic therapy for a mean total duration of 8 weeks prior to synovectomy, and the 10 control subjects each had negative polymerase chain reaction (PCR) results in synovial samples. When the samples were spiked with approximately 1-10 B burgdorferi, all but 1 had positive PCR results, suggesting that spirochetal DNA could have been detected in most of the unspiked samples if it had been present. CONCLUSION: These results indicate that synovial inflammation may persist in some patients with Lyme arthritis after the apparent eradication of the spirochete from the joint with antibiotic therapy.

Adolescent↗
PubMed1999

Anterior urethral injury.

Anterior urethral injuries, although rare, may be associated with substantial long-term morbidity. Urethral injuries that occur due to penetrating trauma or penile fracture are best treated by meticulous two-layer primary repair. Those that occur due to rapid deceleration injury are usually best treated by suprapubic diversion and delayed reconstruction because of associated injuries and concomitant contusion of the supporting spongiosum.

Humans↗
PubMed1999

Repeat vasectomy reversal after initial failure: overall results and predictors for success.

PURPOSE: We review the treatment outcomes for microsurgical reconstruction following failed vasectomy reversal and identify predictors for success. MATERIALS AND METHODS: We performed a retrospective review of our experience with microsurgical reconstruction in 41 men who underwent 1 or more prior unsuccessful vasectomy reversal procedures. Of these patients 20 underwent bilateral (16) or unilateral (4) vasoepididymostomy, 11 underwent bilateral (7) or unilateral (4) vasovasostomy and 10 underwent unilateral vasoepididymostomy with contralateral vasovasostomy. Postoperative followup consisted of serial semen analyses and telephone interviews. RESULTS: Patency and pregnancy followup data were available in 33 and 31 patients, respectively. Five couples had ongoing uncorrected female factor infertility problems and were not included in pregnancy rate calculations. Mean obstructive interval was 10.6 years. Overall patency and pregnancy rates were 79 and 31%, respectively. Mean total motile sperm count for patients demonstrating patency at followup was 38.0 million. History of conception with the current partner was predictive of future conception with 4 of 5 nonremarried couples (80%) initiating a pregnancy versus 3 of 18 remarried couples (17%) (p = 0.006). Other factors, including smoking history and obstructive interval, did not correlate with postoperative success. Reconstruction with vasovasostomy on at least 1 side trended toward improved patency (p = 0.17) and pregnancy rates (p = 0.15), although they did not assume statistical significance. CONCLUSIONS: Microsurgical reconstruction following failed vasectomy reversal is associated with high patency and moderate pregnancy rates at short-term followup. In our series previous conception with the current partner was predictive of future conception after reconstruction. Urologists performing repeat vasectomy reversal must be familiar with microsurgical techniques, since almost three-quarters of patients will require at least unilateral vasoepididymostomy.

Adult↗
PubMed1999

Reconstructive surgery for trauma of the lower urinary tract.

Blunt external trauma is the most common cause of injuries of the lower urinary tract. Minor injuries often heal uneventfully with catheter drainage. Penetrating traumas are best treated with primary repair. Delayed reconstruction of urethral disruption injuries is safe and effective in the majority of cases, but immediate realignment is an attractive, minimally invasive alternative. Pelvic MR imaging and urethral ultrasound are important ancillary staging studies for evaluating patients who require complex urethral reconstruction.

Female↗
PubMed1999

Nitric oxide and nitrogen dioxide concentrations during in vitro high-frequency oscillatory ventilation.

PURPOSE: The purpose of this study was to measure nitric oxide (NO) and nitrogen dioxide (NO2) concentrations, at various ventilatory settings and sampling sites, during in vitro inhaled NO and high-frequency oscillatory ventilation therapy [iNO-HFOV]. MATERIALS AND METHODS: We used a high-frequency oscillatory ventilator (model 3100A, SensorMedics, Yorba Linda, CA), a test lung (model VT-2A Ventilator Tester, Bio-Tek Instruments, Inc., Winooski, VT), nitric oxide delivery and NO/NO2 monitoring (Pulmonox II, Pulmonox, Tofield, Canada), and scavenging systems in this study. The ventilator frequency, amplitude, and inspired oxygen concentration were systematically changed at a fixed flow of NO. The concentrations of NO and NO2, sampled at four sites, were determined by an electrochemical method (Pulmonox II). The NO and NO2 concentrations were measured at the proximal part of the inspiratory limb (site 1), near the Y-piece (site 2), the carina of the test lung (site 3), and the bellows of the test lung (site 4). RESULTS: The concentration of NO decreased significantly (P < .001) from the proximal port (site 11 of the inspiratory circuit (86.16 +/- 0.38 ppm) through the lung bellows (site 4) (70.08 +/- 0.23 ppm). The concentration of NO2 increased significantly (P < .001) from site 1 (3.25 +/- 0.04 ppm) through site 4 (19.4 +/- 0.19 ppm). However, the total concentration of NO + NO2 (NOx) remained unchanged at both site 1 and site 4. Increasing the frequency and amplitude of the ventilator significantly altered NO and NO2 concentrations. The NO2 concentration increased significantly (P < .0001) from 5.6 ppm to 18.1 ppm at site 4 when the fraction of inspired oxygen was increased from 0.25 to 0.93. The NO2 concentration also increased significantly (P < .0001) from 0.6 ppm to 18.7 when NO concentrations were independently increased from 12 ppm to 80 ppm. CONCLUSIONS: During HFOV, the concentrations of NO and NO2 vary between sampling sites and also are influenced by the frequency, amplitude, and inspired oxygen concentration. NO2 concentrations in the lung were significantly increased above commonly accepted toxic concentrations during ventilation with high concentrations of NO (80 ppm) and high fractional concentrations of oxygen. The excessive increase in NO2 concentration at the "alveolar" level in our test lung model warrants confirmation in an in vivo model.

Analysis of Variance↗
PubMed1999

Potato performance in response to different mulches. 1. Nitrogen metabolism and yield.

This work evaluates the impact that the application of different mulches exerts on nitrogen (N) metabolism in roots and leaves and on yield of potato tubers (Solanum tuberosum var. Spunta). The parameters analyzed in this experiment were root temperature; nitrate reductase and nitrite reductase activities; concentrations of nitrates, ammonium, amino acids, proteins, and organic N; dry weight of roots and leaves; and tuber yield. Use of white polyethylene (T2) and white-black plastic (T3) promoted optimal root temperatures for plant growth (23-27 degrees C). Under these experimental conditions, plants showed the greatest efficiency in N utilization and the greatest yield in tubers. Considering the sensitivity of this plant to thermal stress, high root temperatures caused by black polyethylene (>31 degrees C) (T4) depressed N metabolism as well as yield, compared with the results of T2 and T3. Finally, clear polyethylene plastic (T1) caused more damage than did the absence of mulch (control, T0).

Nitrogen↗
PubMed1999

High-sensitive immunophenotyping and DNA ploidy studies for the investigation of minimal residual disease in multiple myeloma.

Sensitive techniques for monitoring minimal residual disease (MRD) in multiple myeloma (MM) are needed to evaluate the effectiveness of new intensive treatment strategies. The aim of the present study was to explore the applicability and sensitivity of flow cytometry immunophenotyping and DNA ploidy studies for the investigation of residual myelomatous plasma cells (PC) in MM patients. Bone marrow (BM) samples from 61 untreated MM patients were immunophenotypically analysed with a panel of 21 monoclonal antibodies, using a high-sensitive method based on a two-step acquisition procedure through a SSC/CD38 -CD138+ 'live-gate'. Overall, in 87% of MM cases, PC displayed an aberrant phenotype at diagnosis. The most important aberrant criteria were: antigen over-expression of CD56 (62%), CD28 (16%) and CD33 (6%) and asynchronous expression of CD117 (28%), sIg (21%) and CD20 (10%). DNA aneuploidy was found in 62% of cases. The simultaneous use of these two techniques allowed the detection of aberrant/aneuploid PC in 95% of the cases. Based on dilutional experiments, the detection limit of both techniques ranged from 10(-4) to 10(-5). In 29 stem cells harvests and 19 BM samples obtained 3 months after autologous transplantation, we have investigated the presence of residual myelomatous PC; they were detected in 44% of the stem cell collections and in 61% of the BM samples obtained after transplant. The percentage of pathological PC did not significantly change during the days of harvest. In summary, the present study shows that the combined use of immunophenotyping and DNA ploidy studies is a suitable approach for MRD investigation in MM patients based on their applicability (95% of cases) and sensitivity (up to 10(-5)).

Bone Marrow Transplantation↗
PubMed1999

Identification of a novel family of targets of PYK2 related to Drosophila retinal degeneration B (rdgB) protein.

The protein tyrosine kinase PYK2 has been implicated in signaling pathways activated by G-protein-coupled receptors, intracellular calcium, and stress signals. Here we describe the molecular cloning and characterization of a novel family of PYK2-binding proteins designated Nirs (PYK2 N-terminal domain-interacting receptors). The three Nir proteins (Nir1, Nir2, and Nir3) bind to the amino-terminal domain of PYK2 via a conserved sequence motif located in the carboxy terminus. The primary structures of Nirs reveal six putative transmembrane domains, a region homologous to phosphatidylinositol (PI) transfer protein, and an acidic domain. The Nir proteins are the human homologues of the Drosophila retinal degeneration B protein (rdgB), a protein implicated in the visual transduction pathway in flies. We demonstrate that Nirs are calcium-binding proteins that exhibit PI transfer activity in vivo. Activation of PYK2 by agents that elevate intracellular calcium or by phorbol ester induce tyrosine phosphorylation of Nirs. Moreover, PYK2 and Nirs exhibit similar expression patterns in several regions of the brain and retina. In addition, PYK2-Nir complexes are detected in lysates prepared from cultured cells or from brain tissues. Finally, the Nir1-encoding gene is located at human chromosome 17p13.1, in proximity to a locus responsible for several human retinal diseases. We propose that the Nir and rdgB proteins represent a new family of evolutionarily conserved PYK2-binding proteins that play a role in the control of calcium and phosphoinositide metabolism downstream of G-protein-coupled receptors.

Amino Acid Sequence↗