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Biomedical subjects

H D Becker

Publications and source records attributed to H D Becker.

At least 343 records · Page 19Linked to original sources
PubMedDate not supplied

Contemporary role of modern brachytherapy techniques in the management of malignant thoracic tumors.

Sole brachytherapy for carcinoma of the lung is most often performed using high-dose-rate (HDR) remote afterloading equipment, which delivers the treatment within the tracheobronchial tree in an outpatient setting. It provides excellent, rapid palliation in advanced stages, and can also be used selectively for curative intent in early stages. In better-performance patients, fractionated external beam radiation therapy (EBRT) is preferred to brachytherapy as an initial treatment because it appears to provide a modest gain in survival, and more sustained palliation. In patients with centrally located tumors and limited extent of disease, the combination of external and endoluminal irradiation enables curative treatment options. Intraoperative brachytherapy may complement standard adjuvant treatment in incompletely resected, unresectable, or medically inoperable patients, and has the potential to improve local control in selected cases. Due to the rarity of the disease, the role of endoluminal brachytherapy in the treatment regimen of tracheal neoplasms is not yet clearly defined. The risk of fatal bleeding after endoluminal brachytherapy appears to be correlated with tumor localization and fraction size, but in the majority of cases fatal bleeds are caused by progression of local disease. The use of a distanceable applicator provides a central positioning of the source, prevents the delivery of high-contact doses to the mucosa, and may reduce toxicity. The standard technique for interstitial brachytherapy after breast-conserving surgery and adjuvant EBRT is the use of low-dose-rate (LDR) brachytherapy, but it may also be applied by means of pulsed-dose-rate (PDR) or HDR techniques. Prospective trials comparing different boost techniques and indications are needed to define more precisely the subgroup of patients who are most suitable for interstitial brachytherapy. Reirradiation of chest wall local recurrences using brachytherapy molds is effective and provides a high local control rate with acceptable toxicity.

Brachytherapy↗
PubMedDate not supplied

Esophageal cancer, early disease: diagnosis and current treatment.

Most esophageal cancers are at a fairly advanced stage at the time of diagnosis, and curative therapy is not possible. For those that are detected early, cure may be possible, particularly if there is no lymphatic spread. Radical therapeutic approaches result in increased treatment-related mortality, high treatment-induced morbidity, and reduced quality of life. Therefore it is one of the major targets in the treatment of esophageal cancers to classify the tumor and to perform adequate stage-related therapy. The modern diagnostic procedures, such as endoscopy, endoluminal sonography, computed tomography (CT) scanning, and endoscopic biopsy, have led to major advances in preoperative staging. Endoluminal sonography is able to predict the depth of tumor infiltration in the esophageal wall and the existence of local lymph node metastasis, whereas CT scanning demonstrates distant metastasis. Histologic classification of the tumor together with genetic and cell biologic characteristics can predict the prognosis. Currently, the best prospect for cure of early esophageal cancer is surgical resection through the abdominothoracic approach, although less radical surgical procedures such as transhiatal resection without extensive lymph node dissection seem to achieve the same results. Even less traumatic is the use of minimal invasive techniques, which certainly will be used more often in the future. For early esophageal cancers limited to the epithelium and the lamina propria, local destruction of the tumor leads to long-term survival and cure. Techniques such as endoscopic resection, laser coagulation, photo-dynamic laser activation, and argon beam exposure have been described and seem to achieve similar results.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma, Squamous Cell↗
PubMedDate not supplied

LaparoLith. A new instrument for stone fragmentation in laparoscopic cholecystectomy.

Laparoscopic cholecystectomy can be performed with incisions of a maximum diameter of 10 mm. The removal of a stone-filled gallbladder at the end of an operation via the 10-mm port needs often-extensive tissue-consuming manipulations for stone removal or minilaparotomy. Stone fragmentation can be achieved by mechanical crushing and by ultrasound-, electrohydraulic-, and tunable dye laser lithotripsy. The clinical employment of the LaparoLith (Baxter Healthcare Corporation), an instrument which allows mechanical fragmentation of stones inside the gallbladder, is presented here. We have used the LaparoLith in nine patients and have been successful in stone fragmentation in seven of these. The LaparoLith seems to be helpful in laparoscopic cholecystectomy, preventing extension of the subnavel incision.

Cholecystectomy, Laparoscopic↗
PubMedDate not supplied

Isolating and maintaining highly polarized primary epithelial cells from normal human duodenum for growth as spheroid-like vesicles.

A method is described for the three-dimensional (3-D) in vitro culture of nontransformed gastrointestinal epithelial cells from the human duodenal mucosa. Biopsies obtained from human duodenum were finely minced. The tissue fragments were suspended in culture medium supplemented with 5% fetal calf serum and the appropriate antibiotics. The suspended mucosal fragments generated spheroid-like multicellular vesicles consisting of highly prismatic absorptive and goblet cells retaining most of the histological features of the tissue in vivo. We performed immunocytochemical studies to determine the origin of the vesicles using monoclonal antibodies against EP4. The histochemistry of the vesicles showed alkaline phosphatase activity. Ultrastructural studies revealed that these cells exhibit characteristics of normal duodenal cells in vivo: apical microvilli, glycocalyx, tight junctions and desmosomes, lateral membrane interdigitations, mucous droplets, and a well-developed Golgi apparatus. An overgrowth of the vesicles by fibroblasts was not seen during cultivation. In contrast with the two-dimensional cell cultures grown on artificial supports, the vesicle cells show organization similar to that of natural epithelia. The polarization and cytoarchitecture of normal gastrointestinal epithelial cells cultured as 3-D vesicles are comparable to those known for the native tissue. This study was undertaken to provide a morphological baseline for subsequent infection experiments.

Antibodies, Monoclonal↗