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Biomedical subjects

H Becker

Publications and source records attributed to H Becker.

At least 73 records · Page 4Linked to original sources
PubMed2001

A new technique for the use of intrathecal fluorescein in the repair of cerebrospinal fluid rhinorrhea using a hypodense diluent.

The intrathecal injection of fluorescein is used in the diagnosis and treatment of skull base liquoric fistulas since it allows precise localization of the site of drainage. The fluorescein is always diluted in cerebrospinal fluid (CSF) resulting in a hyperdense solution in relation to the CSF. For this reason it is necessary to put the patient in the Trendelenburg position for 30 to 40 minutes so that the fluorescein reaches the cerebral cisterns and is visualized at the level of the fistulae. From October 1997 to May 1999 intrathecal fluorescein in a hypodense solution was used in the repair of 23 skull base defects associated with CSF rhinorrhea. This hypodense solution was obtained by diluting 0.5 cm3 of 5% fluorescein in 10 cm3 of distilled water. This solution density is 1001, which is hypodense when compared to CSF (density range 1004-1006) and therefore allows fluorescein to reach rapidly the cerebral cisterns when the patient is recumbent. The author discusses the advantages and the lack of complications with the use of fluorescein in a hypodense solution.

Adolescent↗
PubMed2001

Health promotion practices in women with multiple sclerosis: increasing quality and years of healthy life.

Disease-modifying agents that decrease the accumulation of disability are costly, inconvenient to use, and have the potential of significant side effects. The findings presented here suggest that much less costly health-promotion interventions may hold substantial promise as a complementary strategy for decreasing the burden of functional limitations. Additional research is needed to develop and test interventions that rehabilitation professionals can use to enhance physical activity, nutrition, stress management, and other health-promoting behaviors to increase the quality and years of healthy life for women with MS.

Exercise↗
PubMed2001

African-American women's perceptions of mammography screening.

While mammography has been shown to decrease breast cancer mortality, many African-American women are not receiving annual screenings. African-American women's reasons for not having mammograms are not well understood. This study therefore surveyed 164 African-American women concerning barriers to mammography screening. Outreach coordinators in two urban and one rural site in Texas asked African-American women to complete a checklist about the barriers to mammography screening. The 23-item Mammography Barriers Checklist, which was developed based upon one of the author's clinical experience and the research literature, included both internal and external barriers to screening. Women in all three geographic areas identified fear of finding cancer and mammography cost as the most important reasons for not having mammograms. These results suggest that outreach strategies that address fears related to mammography screening and help women find low-cost mammography resources may be more effective than those focusing strictly on providing information.

Adult↗
PubMed2000

Molecular-scale interface engineering for polymer light-emitting diodes

Achieving balanced electron-hole injection and perfect recombination of the charge carriers is central to the design of efficient polymer light-emitting diodes (LEDs). A number of approaches have focused on modification of the injection contacts, for example by incorporating an additional conducting-polymer layer at the indium-tin oxide (ITO) anode. Recently, the layer-by-layer polyelectrolyte deposition route has been developed for the fabrication of ultrathin polymer layers. Using this route, we previously incorporated ultrathin (<100 A) charge-injection interfacial layers in polymer LEDs. Here we show how molecular-scale engineering of these interlayers to form stepped and graded electronic profiles can lead to remarkably efficient single-layer polymer LEDs. These devices exhibit nearly balanced injection, near-perfect recombination, and greatly reduced pre-turn-on leakage currents. A green-emitting LED comprising a poly(p-phenylene vinylene) derivative sandwiched between a calcium cathode and the modified ITO anode yields an external forward efficiency of 6.0 per cent (estimated internal efficiency, 15-20 per cent) at a luminance of 1,600 candelas per m2 at 5 V.

Journal Article↗
PubMed2000

Polymer microfabrication methods for microfluidic analytical applications.

A growing number of microsystem technology (MST) applications, particularly in the field of microfluidics with its applications in the life sciences, have a need for novel fabrication methods which account for substrates other than silicon or glass. We present in this paper an overview of existing polymer microfabrication technologies for microfluidic applications, namely replication methods such as hot embossing, injection molding and casting, and the technologies necessary to fabricate the molding masters. In addition, techniques such as laser ablation and layering techniques are examined. Methods for bonding and dicing of polymer materials, which are necessary for complete systems, are evaluated.

Chemistry Techniques, Analytical↗
PubMed2000

Treatment of primary tracheal carcinoma. The role of external and endoluminal radiotherapy.

BACKGROUND AND PURPOSE: In a retrospective study the role of radiation therapy for the treatment of primary tracheal carcinoma was investigated. PATIENTS AND METHODS: Between 1984 and 1997, 25 patients with primary tracheal carcinoma were treated with external beam radiotherapy (17 squamous-cell carcinoma [SCC], 8 adenoid cystic carcinoma [ACC], median dose SCC 60 Gy. ACC 55 Gy). An additional brachytherapy boost was carried out in 10/25 patients (median dose SCC 18 Gy, ACC 15 Gy). Ten patients underwent operative treatment. RESULTS: The median survival (Kaplan-Meier) for patients with SCC was 33 months (ACC 94.2). The 1-, 2- and 5-year survival rates (Kaplan-Meier) for patients with SCC were 64.7% (ACC 85.7%), 64.7% (ACC 85.7%), and 26% (ACC 85.7%). Patients with ACC and patients with a complete remission after treatment had a significantly better survival probability (log rank test, p < 0.05). An excellent or good relief of clinical symptoms was achieved in 88% of the patients with SCC (ACC 88%). Eleven patients were locally controlled at last follow-up (SCC: 5/17; ACC: 6/8). Grade 1 to 2 toxicity (RTOG/EORTC) occurred in 12% (SCC: 2/17, ACC: 1/8) and Grade 3 to 4 toxicity in 8% (SCC: 0/17, ACC: 2/8) of the patients. Persistent or progressive local disease caused complications in 5 patients (fatal hemorrhage n = 2, esophagotracheal fistula n = 2, tracheal necrosis n = 1). CONCLUSION: Radiation therapy is an effective treatment for primary tracheal neoplasms. Surgery followed by adjuvant radiotherapy and primary radiotherapy in inoperable cases represent potentially curative treatment options. Prospective multicenter studies are needed to determine the optimal radiotherapeutic approach.

Adult↗
PubMed2000

Effect and toxicity of endoluminal high-dose-rate (HDR) brachytherapy in centrally located tumors of the upper respiratory tract.

AIM: To assess effect and toxicity of high-dose-rate afterloading (HDR) alone or in combination with external beam radiotherapy (EBRT) in centrally located tumors of the upper respiratory tract. PATIENTS AND METHODS: From 1987 to 1996, 55 patients were treated. Twenty-one patients (group A1: 17 non-small-cell lung cancer [NSCLC], A2: 4 metastases from other malignancies) were treated using HDR alone due to a relapse after external beam irradiation. In 34 previously untreated and inoperable patients (group B1: 27 NSCLC, B2: 7 metastases from other malignancies) HDR was given as a boost after EBRT (30 to 60 Gy, median 50). HDR was carried out with a 192Ir source (370 GBq). The brachytherapy dose (group A: 5 to 27 Gy, median 20; B: 10 to 20 Gy, median 15) was prescribed to 1 cm distance from the source axis. A distanciable applicator was used in 39/55 patients. RESULTS: In group A1, a response rate (CR, PR) of 53% (group B1: 77%) was reached. The median survival (Kaplan-Meier) was 5 months in group A1 (B1: 20 months). The 1-, 3- and 5-year local progression free survival rates (Kaplan-Meier) were 66% (15%), 52% (0%), and 37% (0%) in group B1 (group A1). Prognostic favorable factors in group B1 were a tumor diameter < 20 mm, the lack of radiological mediastinal involvement, a complete remission, and a Karnofsky performance status > 70. Grade-1 or 2 toxicity (RTOG/EORTC) occurred in 0% in group A and in 6% in group B. We observed no Grade-3 or 4 toxicity. Complications caused by persistent or progressive local disease occurred in 3 patients in group A (fatal hemorrhage, tracheomediastinal fistula, hemoptysis) and in 2 patients in group B (fatal hemorrhage, hemoptysis). CONCLUSIONS: HDR brachytherapy is an effective treatment with moderate side effects. In combination with external beam irradiation long-term remissions can be reached in one third of the patients.

Adult↗
PubMed2000

[Laparoscopy in small bowel ileus].

Today laparoscopic procedures are routinely performed in patients with intestinal adhesions from previous abdominal surgery. Does laparoscopy have a potential benefit in acute small-bowel obstruction? Theoretically, a lower rate of wound complications and incisional hernias, as well as less subsequent adhesions with a lower incidence of recurrent intestinal obstruction, can be expected. However, laparoscopy is successful in only 50-70% of selected patients, thereby representing the highest rate of conversion in minimally invasive surgery. Laparoscopic management of severe abdominal distension with massively dilated and fragile small-bowel or dense adhesions is extremely difficult even when performed by experienced surgeons. Significantly prolonged operating time, the high risk of bowel injury (> 6-10%) and an increased frequency of early reoperations jeopardize the patient's safe outcome. However, in strictly selected patients the laparoscopic approach may be promising. In acute intestinal obstruction without a history of previous abdominal surgery, laparoscopy is--in the absence of adhesions--an excellent diagnostic tool and may also be a successful therapeutic modality in a variety of bowel-obstruction etiologies. Furthermore, the laparoscopic option should be considered in patients who previously had undergone small laparotomies (e.g., appendectomy) or laparoscopic surgery. We recommend "postlaparoscopic" intestinal obstruction as the ideal case for laparoscopic reexploration. Incarcerated hernias at the site of trocar insertion or adhesions due to peritoneal tears are easily identified as the cause of obstruction and successfully cured with the laparoscope. In conclusion, we advocate the laparoscopic approach in acute small-bowel obstruction exclusively for selected patients. Clinical studies are required to define appropriate surgical indications objectively.

Contraindications↗
PubMed2000

Diagnostic value of the fast-FLAIR sequence in MR imaging of intracranial tumors.

The aim of this study was to quantify imaging characteristics of fast fluid-attenuated inversion recovery (FLAIR) sequence in brain tumors compared with T1-postcontrast- and T2-sequences. Fast-FLAIR-, T2 fast spin echo (FSE)-, and T1 SE postcontrast images of 74 patients with intracranial neoplasms were analyzed. Four neuroradiologists rated signal intensity and inhomogeneity of the tumor, rendering of cystic parts, demarcation of the tumor vs brain, of the tumor vs edema and of brain vs edema, as well as the presence of motion and of other artifacts. Data analysis was performed for histologically proven astrocytomas, glioblastomas, and meningiomas, for tumors with poor contrast enhancement, and for all patients pooled. Only for tumors with poor contrast enhancement (n = 12) did fast FLAIR provide additional information about the lesion. In these cases, signal intensity, demarcation of the tumor vs brain, and differentiation of the tumor vs edema were best using fast FLAIR. In all cases, rendering of the tumor's inner structure was poor. For all other tumor types, fast FLAIR did not give clinically relevant information, the only exception being a better demarcation of the edema from brain tissue. Artifacts rarely interfered with evaluation of fast-FLAIR images. Thus, fast FLAIR cannot replace T2-weighted series. It provides additional information only in tumors with poor contrast enhancement. It is helpful for defining the exact extent of the edema of any tumor but gives little information about their inner structure.

Adolescent↗
PubMed2000

Persistent hypocalcemia with elevated parathyroid hormone levels after long-term primary hyperparathyroidism: report of a case.

We report herein the case of a 48-year-old man with long-term persistent primary hyperparathyroidism (pHPT) despite undergoing a parathyroidectomy in 1976, followed by a reoperation in 1978, for whom resection of a parathyroid adenoma in the upper mediastinum was eventually performed. His postoperative course was complicated by recurrent hypocalcemia refractory to oral calcium substitution and significantly elevated levels of parathyroid hormone (PTH). The radiological findings are presented, and we discuss the possible reasons for the coincidence of severe hypocalcemia with increased PTH levels in association with pHPT.

Adenoma↗
PubMed2000

Sesqui- and diterpenes from the liverwort Gackstroemia decipiens.

Six rosanes, 5 beta,11 beta-dihydroxy-ros-15-ene, 5 beta,12 beta-dihydroxy-ros-15-ene, 11 beta-hydroxy-7-oxo-rosa-5,15-diene, 1 alpha,5 beta,11 beta-trihydroxy-7-oxo-ros-15-ene, 5 beta,20-epoxy-20-hydroxy-ros-15-ene and 5 beta,20-epoxy-20-methoxy-ros-15-ene along with the enantiomer of the already reported 11 beta-hydroxy-rosa-5,15-diene and the known 5 beta-hydroxy-ros-15-ene have been isolated from the liverwort Gackstroemia decipiens. Furthermore, the sesquiterpenes 3-acetoxy-7,11-dihydroxy-farnesa-1,5,9-triene and 1 beta,10 beta-epoxy-nardosin-7,11-diene were identified. Their structures were elucidated by NMR spectroscopy.

Diterpenes↗
PubMed2000

Sesquiterpenoids and diterpenoids from the Chilean liverwort Lepicolea ochroleuca.

The ether extract of the Chilean liverwort Lepicolea ochroleuca yielded three sesquiterpenoids, ent-4 beta-Hydroxy-10 alpha-methoxyaromadendrane, ent-3 beta-Hydroxyspathulenol, and 1,10-Dioxotayloriane, as minor components. The major components were ledol and 13-epi-neoverrucosan-5 beta-ol, four other minor fusicoccanoids were identified.

Diterpenes↗
PubMed2000

Reliability of peroneal reaction time measurements.

OBJECTIVE: The purpose of this study was to demonstrate the reliability of reaction time-measurements on a tilting platform under consideration of various influencing factors. DESIGN: The peroneal reaction time of 30 healthy subjects was examined in an experimental study. BACKGROUND: Peroneal reaction time measurements have been used to objectively evaluate functional instability of the ankle joint, but the reliability of the method has not been proven yet. METHODS: The reaction time after sudden inversion of the ankle were determined by surface EMG. RESULTS: The median latency of the peroneus brevis was 66 ms and that of the peroneus longus was 63 ms. No differences between male and female subjects and between left and right legs could be found. An increase of reaction time was caused by neuromuscular fatigue (P=0.033, for both the peroneus brevis and the peroneus longus). A decrease in reaction time resulted if the foot was held in 15 degrees of plantar flexion (P=0.0004 for the peroneus brevis, P=0.002 for the peroneus longus). The reliability was examined by circadian and by day-to-day measurements. The coefficient of correlation (Spearman's rho) between the peroneus brevis and days 1-5 was 0.67 (P=0.177) and for the peroneus longus 0. 00 (P0.999). The same results were obtained after the circadian measurements. CONCLUSION: Determination of peroneal reaction time was proven as a reliable measurement method. RELEVANCE: Reliability and validity are basic preconditions of a test to become accepted as a clinical measurement method. This paper demonstrates the reliability of measuring the peroneal reaction time. Thus, assuming validity, the peroneal reaction time measurement is justified as a clinical test.

Adult↗
PubMed2000

Improvement in Salmonella detection in milk and dairy products: comparison between the ISO method and the Oxoid SPRINT Salmonella test.

The Oxoid SPRINT Salmonella test was compared with the ISO method (ISO 6579: 1993) for the detection of Salmonella in milk and dairy products. Samples were artificially contaminated, in some cases with sublethally injured salmonellas. Experiments with raw milk, soft cheese made from heat-treated milk (mould-ripened and with smear) and soft cheese with smear made from raw milk showed no significant differences between the SPRINT and ISO methods. With dried milk products and mould-ripened soft cheese made from raw milk the reference method gave significantly more positive results. The addition of ferrioxamine E to pre-enrichment (ISO) or pre-enrichment/enrichment broth (SPRINT test) did not improve Salmonella detection.

Culture Media↗
PubMed2000

Problems with intraoperative hyperthermic peritoneal chemotherapy for advanced gastric cancer.

BACKGROUND: Intraoperative hyperthermic peritoneal chemotherapy (IHPC) after total gastrectomy for advanced, serosa-penetrating gastric cancer has been demonstrated in several studies to reduce the incidence of peritoneal carcinosis and to prolong survival. METHODS: In a prospective pilot study, nine patients with advanced gastric cancer were selected to receive IHPC with Mitomycin and Cisplatin after total gastrectomy and systematic lymphadenectomy. RESULTS: All patients had nodal, and four patients distant, metastases. Six patients (66%) suffered from post-operative complications including renal failure, pancreatitis, pancreatic fistula and anastomotic dehiscence. Thirty-day mortality was zero. Six patients died within 3-10 months after surgery. Five of these deaths were related to peritoneal carcinosis and one patient died from cardiac failure 3 months after surgery. Three patients, respectively, have been alive for 12, 20 and 24 months at present, with suspected peritoneal tumour in the last patient. The 2-year probability of survival among our patients receiving IHPC is 29%. CONCLUSION: Intraoperative hyperthermic peritoneal chemotherapy carries a high risk of peri-operative complications and was not able to prevent or delay peritoneal tumour recurrence in patients with advanced gastric cancer.

Aged↗