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Biomedical subjects

E Saiz

Publications and source records attributed to E Saiz.

14 recordsLinked to original sources
PubMed2001

Bioactive glass-mesoporous silica coatings on Ti6Al4V through enameling and triblock-copolymer-templated sol-gel processing.

The combination of thick glass coatings that can protect Ti6Al4V from corrosion in the body fluids, and mesoporous silica films able to readily induce the formation of apatite when immersed in a simulated body fluid (SBF), has been investigated in this work as a possible route towards more resistant and long-lasting implants. Glasses in the system Si-Ca-Mg-Na-K-P-O with thermal expansion coefficients close to that of Ti6Al4V were prepared and used to coat this alloy by an enameling technique. However, the glasses apt to coat Ti6Al4V exhibited a very limited capacity to induce apatite formation in SBF. In order to enhance their bioactivity, a thin film of mesoporous silica was applied on the exterior of the specimens by spin coating a sol-gel solution. When tested in SBF, these coatings induced apatite formation after 7 days. The mesoporosity of the silica film was created through a triblock-copolymer-templating process. The diameters of the mesochannels could be adjusted by changing the size of the directing agent. A preferred alignment of the mesostructure was observed. The removal of the organic templates could be achieved through a photocalcination treatment, which, compared to conventional thermocalcination, offered several advantages.

Alloys↗
PubMed2000

Bioactive glass coatings with hydroxyapatite and Bioglass particles on Ti-based implants. 1. Processing.

Silicate-based glasses with thermal expansion coefficients that match those of Ti6A14V were prepared and used to coat Ti6A14V by a simple enameling technique. Bioglass (BG) or hydroxyapatite (HA) particles were embedded on the coatings in order to enhance their bioactivity. HA particles were immersed partially during heating and remained firmly embedded on the coating after cooling. There was no apparent reaction at the glass/HA interface at the temperatures used in this work (800-840 degrees C). In contrast, BG particles softened and some infiltration into the glass coating took place during heat treatment. In this case, particles with sizes over 45 microm were required, otherwise the particles became hollow due to the infiltration and crystallization of the glass surface. The concentration of the particles on the coating was limited to 20% of surface coverage. Concentrations above this value resulted in cracked coatings due to excessive induced stress. Cracks did not propagate along the interfaces when coatings were subjected to Vickers indentation tests, indicating that the particle/glass and glass/metal interfaces exhibited strong bonds. Enameling, producing excellent glass/metal adhesion with well-attached bioactive particles on the surface, is a promising method of forming reliable and lasting implants which can endure substantial chemical and mechanical stresses.

Alloys↗
PubMed2000

Isolated Langerhans cell histiocytosis of the thyroid: a report of two cases with nuclear imaging-pathologic correlation.

We describe two cases of isolated langerhans cell histiocytosis (LCH) of the thyroid gland, one of which was found in conjunction with an incidental papillary carcinoma. The first case was that of a 43-year-old man who presented with a 1- to 2-cm nodule within the left lobe of the thyroid. Fine-needle aspiration cytology revealed atypical cells with convoluted nuclei in a background of eosinophils and lymphocytes. The findings prompted a recommendation for excision secondary to the high suspicion of a hematologic malignancy. Histologic sections demonstrated LCH in association with a small focus of papillary carcinoma. The second case involved a 43-year-old woman who presented with a 1.8-cm nodule within the right lobe of the thyroid. Fine-needle aspiration in this case demonstrated abundant hemosiderin-laden macrophages, occasional lymphocytes, and a single benign sheet of follicular cells. No eosinophils were seen; however, a single group of atypical histiocytic cells with cleaved nuclei was noted. The nodule was subsequently resected. Histologic examination demonstrated LCH in association with follicular nodular hyperplasia with cystic degeneration. Immunohistochemical studies were performed in both cases, revealing CD1a and S100 immunoreactivity in the Langerhans' cells. Although LCH may occur as a manifestation of systemic disease, its occurrence as an isolated finding in the thyroid is rare. Its occurrence in association with papillary carcinoma of the thyroid is even more uncommon. We present two cases of isolated LCH of the thyroid, one of which was found in association with papillary carcinoma of the thyroid. The cytologic, histologic, immunohistochemical, and radiologic features are described in each case. The ultrastructural findings from the first case are also presented.

Adult↗
PubMed1999

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Journal Article↗
PubMed1999

Glass-based coatings for titanium implant alloys.

Glass coatings on Ti6Al4V were prepared using a simple enameling technique. The composition of the glasses was tailored to match the thermal expansion of Ti6Al4V. By controlling the firing atmosphere, time, and temperature, it was possible to control the reactivity between the glass and the alloy and to fabricate coatings (25-150 micron thick) with excellent adhesion to the substrate. The optimum firing temperatures ranged between 800 and 840 degrees C at times up to 1 min in air or 15 min in N2. The same basic technique was used to prepare multilayered coatings with graded composition or with hydroxyapatite (HA) particles embedded in the outer layer. Some of these coatings presented excellent adhesion to the substrate and were able to form HA during in vitro tests in simulated body fluid.

Alloys↗
PubMed1999

Infiltrating breast carcinoma smaller than 0.5 centimeters: is lymph node dissection necessary?

BACKGROUND: The incidence of axillary lymph node metastases from infiltrating breast carcinomas measuring 1.0 cm or smaller reported in the literature varies from 0% (for tumors measuring < or =0.5 cm) to 27.1% (for all tumors < or =1 cm). METHODS: The authors examined all infiltrating breast carcinomas measuring 1.0 cm or smaller with axillary lymph node dissections in patients seen at their institution between January 1990 and March 1997 (117 cases) to determine the incidence of axillary lymph node metastases. All tumors were evaluated for patient age, histologic type of tumor, modified Bloom-Richardson grade, estrogen and progesterone receptor status, ploidy, S-phase fraction, and angiolymphatic vessel invasion, to determine whether there was a relation between the indicators and axillary lymph node metastases. The authors also performed immunohistochemical stains for the basement membrane components laminin and Type IV collagen on the tumors demonstrating metastases and on an equal number of size- and date-matched tumors not demonstrating metastases. RESULTS: Twelve cases of infiltrating carcinoma with axillary lymph node metastases were identified (a 10.3% overall incidence of metastases). Lymph node metastases were not identified in any of the cases with tumors measuring < or =0.5 cm (24 cases). The incidence of axillary lymph node metastases for carcinomas 0.6-1.0 cm was 12.9% (12 of 93 cases). High nuclear grade was found to correlate with the presence of lymph node metastases (P = 0.007). No statistically significant correlation was found between the other indicators examined and axillary lymph node metastases or between basement membrane staining and axillary lymph node metastases. CONCLUSIONS: The authors concluded that infiltrating breast carcinomas measuring < or =0.5 cm are unlikely to have demonstrable axillary lymph node metastases. Lymph node dissections in these women may be unnecessary. Nuclear grade may be the best predictor of lymph node metastases in T1b tumors.

Axilla↗
PubMed1999

Metastatic germ cell tumor to the heart presenting with syncope.

Malignant nonseminomatous germ cell tumors (NSGCT) rarely metastasize to the heart. The first such case presenting with syncope is described. Eight previously described cases of NSGCT with intracaval metastasis to the heart are reviewed and the literature to date is discussed. Transesophageal echocardiography is the diagnostic study of choice and treatment consists primarily of platinum-based chemotherapy followed by surgical resection of residual deposits.

Adult↗
PubMed1998

Lactococcus garvieae endocarditis: report of a case and review of the literature.

Bacterial endocarditis due to Lactococcus garvieae is extremely unusual, and may actually be underreported due to its morphologic and biochemical similarities with enterococci. Only three cases have been reported in the medical literature, and all involved prosthetic valves. We report a case of native valve bacterial endocarditis caused by L. garvieae.

Aged↗
PubMed1998

The modified Steiner stain: a new use for an old stain? Staining cytomegalovirus-infected cells in gastrointestinal biopsies.

The modified Steiner stain is a non-specific silver stain for identifying bacteria in formalin-fixed, paraffin-embedded tissues. The principle behind its use is that bacteria are first sensitized using uranyl nitrate solution, making them able to precipitate silver from a silver nitrate solution. It is used routinely for staining gastric biopsies to identify Helicobacter pylori. Upon staining a gastric biopsy from a patient with acquired immunodeficiency syndrome (AIDS) and cytomegalovirus gastritis, we recognized that this technique also stains the viral inclusions of cytomegalovirus-infected cells. We then proceeded to stain 43 consecutive cytomegalovirus-positive gastrointestinal biopsies from 33 immunocompromised patients based on positive cytomegalovirus immunohistochemistry (DAKO-cytomegalovirus monoclonal antibody, clones DDG9 and CCH2). We also stained eight cytomegalovirus-infected, non-gastrointestinal tissues, including lung, adrenal gland, ovary, skin and neural tissue, to ensure that the stain was staining the cytomegalovirus-infected cells and not argyrophilic or argentaffin neuroendocrine cells of the gastrointestinal tract. In 40 of the 43 cytomegalovirus-infected gastrointestinal biopsies, we saw positive staining with the modified Steiner stain (93% sensitivity). The cytomegalovirus-infected, non-gastrointestinal tissues all stained positively with the modified Steiner stain. Because the modified Steiner stain is frequently used to identify Helicobacter pylori in gastric biopsies, we propose that it be studied further for possible use either as a screen or as a confirmatory tool, or both, for cytomegalovirus inclusions in gastrointestinal biopsies.

Cell Nucleus↗
PubMed1981

[Thermal resistance of Candida tropicalis and Rhodotorula rubra in orange juice].

The thermal resistance of two yeasts (Candida tropicalis and Rhodotorula rubra) was studied. The yeasts were isolated from Venezuelan pasteurized orange juice obtained at retail level. The flask method was utilized, applying temperatures which ranged from 49.5 to 53.5 degrees C to initial populations of 1x10(5) cells/ml of orange juice. Values of D50C=3.4 min and z=4.1 degrees C were found for C. tropicalis, and D50C=2.6 min and z=9.8 degrees C for R. rubra. Linear correlation coefficients of r=0.99 and r=0.98 wee obtained, respectively, for the experimental data.

Beverages↗