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Biomedical subjects

J R Alvarez

Publications and source records attributed to J R Alvarez.

10 recordsLinked to original sources
PubMed2006

Electrical and optical properties of C46H22N8O4KM (M=Co, Fe, Pb) molecular-material thin films prepared by the vacuum thermal evaporation technique.

In this work, the synthesis of new materials formed from metallic phthalocyanines (Pcs) and double potassium salt from 1,8-dihydroxianthraquinone is reported. The newly synthesized materials were characterized by scanning electron microscope (SEM), atomic force microscopy (AFM), infrared (IR) and Ultraviolet-visible (UV-vis) spectroscopy. The powder and thin-film samples of the synthesized materials, deposited by vacuum thermal evaporation, show the same intra-molecular bonds as in the IR spectroscopy studies, which suggests that the thermal evaporation process does not alter these bonds. The effect of temperature on conductivity and electrical conduction mechanism was measured in the thin films (approximately 137 nm thickness). They showed a semiconductor-like behaviour with an optical activation energy arising from indirect transitions of 2.15, 2.13 and 3.6eV for the C(46)H(22)N(8)O(4)KFe, C(46)H(22)N(8)O(4)KPb and C(46)H(22)N(8)O(4)KCo thin films.

Cobalt↗
PubMed2000

[Percutaneous endoscopic gastrotomy (GEP): designed reusable (NAGEP) for one time endoscopic technique. Experimental study in dogs].

INTRODUCTION: This aim of our experimental study was to demonstrate the versatility of our designed reusable device for PEG and its future application in humans. MATERIALS AND METHODS: 20 mongrel dogs received enteral nutrition by a Foley tube placed by a single endoscopic technique using a reusable stainless steel designed device, three reusable stainless steel designed device, three reusable stainless steel dilators, an Olympus XQ20 video gastrointestinal endoscope, basic surgical equipment and surgical material. RESULTS: The procedure was successfully performed in all dogs under general anaesthesia. The duration of the whole procedure ranged from 10 to 18 min. The complications regardless by the PEG procedure were minimal. The Foley tube was retained by 15 days. CONCLUSIONS: The application of the stainless steel reusable designed device for the PEG is safe, and presents several advantages. This technique for PEG placement could be used in the future due the characteristics of the designed device: durable and reusable for unlimited number of procedures.

Animals↗
PubMed1998

The relationship of psychological-mindedness to adult perceptions of early parental rejection.

We tested the hypothesis that highly psychologically minded individuals perceive having grown up with rejecting parents. A Psychological Mindedness (PM) Scale, and the Parent-Child Relations Questionnaire II (PCR), were administered to 120 college students. Contrary to prediction, a significant negative correlation was found between PM and perceptions of early maternal rejection. Psychological-mindedness, it was suggested, may be attributable to "good enough mothering" and may be learned through modeling and imitation of mothers' empathic perceptions, affective responses, and behavior.

Adolescent↗
PubMed1992

Improved detection of HIV p24 antigen in serum after acid pretreatment.

HIV-1 p24 antigen was detected in 554 sera (509 from HIV-1 seropositive individuals and 45 sera from seronegative controls) using a conventional method with acid pretreatment of the sample in order to separate the p24 antigen/anti-p24 antibody immune complexes. In asymptomatic individuals there was a substantial increase in antigen detection (48.2% vs 8.4%). Similar results were also observed in ARC (59.1% vs 12.2%) and AIDS patients (85.7% vs 37.1%). It can be concluded that the acid treatment improves the sensitivity of conventional techniques to detect HIV-1 p24 antigen.

Female↗
PubMed1983

Viral hepatitis.

Explore the source record for details and available documents.

Carrier State↗
PubMed1982

Interactions of soybean lectin, soyasaponins, and glycinin with rabbit jejunal mucosa in vitro.

Mucosal samples from rabbit jejunum were incubated (30 min, 25 degrees C) with (125I)glycinin in the presence of buffer, soybean lectin (50 micrograms/ml) soyasaponins (1 mg/ml), or both lectin and saponins. The mucosal uptake of (125I)glycinin was negligible with buffer, and increased progressively with additions of soybean lectin (P less than 0.05), soyasaponins (P less than 0.005), and both (P less than 0.0001). The stimulation of uptake by lectin and saponins together was greater than the sum of their individual effects (P less than 0.0005). The effect of soybean lectin on glycinin uptake was concentration dependent, reaching a maximum at approximately 50 micrograms/ml for the stimulation of uptake in the presence of saponins, and was inhibited by D-GaINAc. Although the mechanisms involved in mucosal uptake of glycinin cannot be described from these data, we have assumed the presence of two independent pathways for lectin-stimulated and saponin-induced uptakes. In addition, we have proposed that soybean lectin, by binding to terminal galactoside sites at the enterocyte apical membrane, enhances a crenator effect of saponins that leads to increasing leakage of glycinin into the cell.

Animals↗
PubMed1982

Clinical experience with the Ionescu-Shiley xenograft valve: four to five-year follow-up.

Between January 1977 and July 1981, 132 Ionescu-Shiley xenografts were implanted in 124 patients. Early and late mortality was 13.7% (17/124) and 9.2% (10/107), respectively. Cumulative survival rates at 4 to 5 years were 76% (aortic) and 84% (mitral). Thromboembolic analysis showed 0.72 episodes per 100 patients per year, without chronic anticoagulation. The thromboembolism free rates were 96.8% (mitral) and 100% (aortic); 75% of the mitral patients were in atrial fibrillation. No primary valve dysfunction was detected. In the aortic position (8 patients with valve stent diameter from 19 to 25 mm), the mean peak systolic gradient pressure was 10 +/- 5.5 mm Hg, and calculated valve surface areas were 1.6 +/- 0.5 cm2 at rest and 2 +/- 0.1 cm2 after exercise. A satisfactory correlation between catheterization-derived valve area (from hemodynamic data) and valve stent diameter was obtained (r = 0.94). In the mitral position, the mean diastolic gradient pressure was 4.7 +/- 3.1 mm Hg at rest and 13.8 +/- 0.9 after exercise with the 27 mm xenograft. The corresponding calculated surface areas were 2.8 +/- 6 cm2 and 3 +/- 0.8 cm2. The present data show minimal thrombogenicity without chronic anticoagulation, even in patients with atrial fibrillation or enlarged left atrium and advantageous hemodynamic characteristics, particularly in those with small aortic annuli.

Journal Article↗