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Biomedical subjects

H Becker

Publications and source records attributed to H Becker.

At least 91 records · Page 5Linked to original sources

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↗

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↗

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↗

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↗

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↗

Uncommon metastasis of a glioblastoma multiforme in liver and spleen.

A case of a glioblastoma multiforme is presented. Craniotomy was performed with total resection of the right temporal tumor. Postoperatively, the patient received adjuvant radiotherapy, but 6 months after therapy he developed severe nausea and weight loss. Recurrence of an intracranial tumor in the right temporal region with nodules in the liver and spleen were detected by CT scan. Fine-needle biopsies of the liver confirmed the diagnosis of a glioblastoma metastasis with characteristic immunohistochemical staining for glial fibrillary acidic protein. This rare case of an intracerebral glioblastoma metastasizing to liver and spleen was managed by systemic chemotherapy.

Brain Neoplasms↗

Mailed survey follow-ups--are postcard reminders more cost-effective than second questionnaires?

Finding cost-effective ways to increase response to mailed surveys is a concern for many nurse researchers. This study compared two follow-up methods: sending a second questionnaire packet versus sending a reminder postcard to those who did not respond to an initial mailing. Although the second questionnaire yielded a higher response than did the postcard, the cost per additional response was approximately 2 1/2 times higher for the questionnaire than for the postcard when the differential cost of the two mailings is considered.

Cost-Benefit Analysis↗

How organizational factors contribute to innovations in service delivery.

Twelve staff members from three community centers providing services to people with mental retardation were interviewed about the implementation of a new approach to service delivery that utilized Essential Lifestyle Planning. Findings indicate that although the innovation proposed and the technical assistance provided were quite similar, the outcomes varied greatly across the three sites. By highlighting the importance of organizational factors, such as timing and agency supports, these findings provide direction for future training and technical assistance activities of those who promote change in service-delivery philosophy and methods.

Adult↗

[Basic tenets for quality circles in North Rhine Medical Service of Public Health Insurance].

The Medical Advisory Service of the Health Insurance in the area of the Northern Rhine (MDK Nordrhein) has set up an internal concept for quality management since 1998. This concept includes the installation and performance of quality circles. Staff members were internally qualified as "presenters". They worked out principles for quality circles of the MDK North Rhine which were implemented as binding basic rules by the managing conference of the MDK. The principles will be presented in detail.

Germany↗

Low-dose high-resolution CT of the petrous bone.

PURPOSE: To show that CT of the petrous bone can be realized using a low-dose technique. MATERIAL: and methods: A high-contrast phantom was scanned with 1.5 mm slice thickness and 60-510 mAs using the reconstruction algorithms standard, bone and edge. In 50 patients, the petrous bone was examined using the standard protocol at 510 mAS. Additionally, selected slices were made at 120 or 210 mAs. The resolution of relevant structures was compared. Phantom studies were repeated on a second CT-device; images of patients scanned with 80 mAs were analyzed in regard to resolution of osseous details. RESULTS: With the first CT-device structures of the phantom up to 0. 5 mm were depicted using 510 mAs and the edge kernel. With 120 mAs and the bone kernel structures of 0.6 mm could be distinguished. Although the same resolution was achieved with 60 mAs and the edge kernel, patient examinations showed a profound image noise. The results achieved with 120 mAs and the bone algorithm, however, were equal to that of 510 mAs. With the second device the same image quality was realized with only 80 mAs. CONCLUSION: CT-examinations of the petrous bone can be effected without loss of diagnostic information using only 15% of the radiation dose used for a standard brain examination.

Humans↗

Biosynthesis of a neo-epi-verrucosane diterpene in the liverwort Fossombronia alaskana. A retrobiosynthetic NMR study.

The biosynthesis of the diterpene 8alpha-acetoxy-13alpha-hydroxy-5-oxo-13-epi- neoverrucosane in the arctic liverwort Fossombronia alaskana was studied by incorporation experiments using [1-(13)C]- and [U-(13)C(6)]glucose as precursors. The (13)C-labeling patterns of acetyl-CoA, pyruvate, and phosphoenolpyruvate in intermediary metabolism were reconstructed from the (13)C NMR data of biosynthetic amino acids (leucine, alanine, phenylalanine) and were used to predict hypothetical labeling patterns for isopentenyl pyrophosphate formed via the mevalonate pathway and the deoxyxylulose pathway. The labeling patterns observed for the neoverrucosane diterpene were consistent with the intermediate formation of geranyllinaloyl pyrophosphate assembled from dimethylallyl pyrophosphate and three molecules of isopentenyl pyrophosphate generated predominantly or entirely via 1-deoxyxylulose 5-phosphate. The experimental data can be integrated into a detailed biosynthetic scheme involving a 1,5-hydride shift. The postulated involvement of the 1,5-hydride shift was confirmed by an incorporation experiment with [6,6-(2)H(2)]glucose.

Diterpenes↗

On the effect of xenin and xenin fragments on exocrine pancreas secretion in vivo.

A stimulatory effect on exocrine pancreas secretion could be demonstrated with high concentrations of the 25-amino-acid peptide xenin in non-anesthetized dogs. This peptide has been isolated from gastric mucosa and it is part of a structural coat protein. It has close structural similarities to neurotensin. The longer C-terminal fragments xenin-(13--25) and xenin-(18--25) are essential for the stimulation of exocrine pancreas secretion in vivo. The smaller peptide fragments xenin-(21--25) and xenin-(22--25) failed to stimulate the pancreas as well as the N-terminal peptide fragment xenin-(1--23). The stimulatory effects of xenin may be mediated via neural neurotensin pathways, because neurotensin receptor blockade abolished the stimulatory effect on pancreatic secretion. Cholinergic pathways are not involved, because atropine had no inhibiting effect.

Adjuvants, Anesthesia↗

Outcome of palliative urinary diversion in the treatment of advanced malignancies.

BACKGROUND: It is unclear whether palliative endourologic or percutaneous urinary diversion in the treatment of advanced cancer provides significant improvement in quality or duration of life. The purpose of this study was to evaluate survival and performance status after endourologic palliative urinary diversion in patients with advanced malignancy and to compare the results for different malignancies. METHODS: One hundred three patients with advanced malignancies underwent palliative urinary diversion (stent or nephrostomy) between 1986 and 1997. Ninety-two patients and 11 patients had bilateral and unilateral obstruction, respectively. Indications, complications, performance status after diversion, and survival for patients with different malignancies were identified and compared. A modified Karnofsky performance scale (KPS) was used for assessment of physical performance. A scale of 0-4 was used: 0) hospitalized until death; 1) bedridden at home, severe pain despite analgesia; 2) moderate disability, moderate pain despite analgesia; 3) mild disability, pain free with medication; and 4) normal. RESULTS: The mean age of patients was 68 years. The mean pre- and postoperative creatinine levels were 6 mg/dL and 3.3 mg/dL, respectively (P < 0.0001). The median survival and days of hospitalization were 112 and 45, respectively. The median postdiversion KPS score was 2 (range, 0-4), and 15% of patients never left the hospital. Overall, 51% required secondary percutaneous procedures, and 68.4% had complications (minor, 63%; major, 5.4%). CONCLUSIONS: Most patients with advanced cancers had poor performance status and survival after diversion. Eighty six percent had cancer-related symptoms despite the diversion. The average survival was 5 months, 50% of which was spent in the hospital. Primary endourologic procedures had a high failure rate, and additional procedures were required.

Aged↗

Contribution of low-dose CT-scan protocols to the total positioning error in computer-assisted surgery.

PURPOSE: To quantify the contribution of a computed tomography (CT) scan to navigation accuracy in computer-assisted surgery. METHODS: Eighty-eight patients undergoing computer-assisted facial or skull-base surgery were fitted preoperatively with 4 to 12 markers, either attached to the skin (n = 20) or fixed in the osseous skull (micro-screws; n = 68). Low-dose high-resolution spiral CT was achieved with 25-cm field of view (FoV), 1-mm slice thickness, 2-mm table increment, 1-mm reconstruction interval, 140 kV, 40 mA, bony reconstruction algorithm, and 180 degrees reconstruction profile (effective slice thickness = 1.8 mm). During surgery, navigation accuracy was evaluated using two navigation systems. RESULTS: Mean error was 0.66 mm for osseous markers and 1.58 mm for cutaneous markers. Both values are markedly smaller than the effective slice thickness of the scan protocol used. Radiation exposure of the patient for the entire examination never exceeded that necessary for one single 10-mm slice in a standard brain examination. Despite the reduced dose, landmarks and fiducials were precisely identified in all cases. CONCLUSIONS: The CT-induced positioning error in the Z-axis is considerably reduced by overlapping raw data reconstruction. For 1-mm slices and a 25-cm FoV, the average scan-induced positioning error is about 0.3 mm. Spatial resolution is not affected by the low dose applied. For MRI-based navigation, a 1 mm3 voxel size is the best compromise between signal-to-noise ratio, spatial resolution and scan time.

Algorithms↗