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Biomedical subjects

H Becker

Publications and source records attributed to H Becker.

At least 127 records · Page 7Linked to original sources
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↗
PubMed2000

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↗
PubMed2000

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↗
PubMed2000

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↗
PubMed2000

[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↗
PubMed2000

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↗
PubMed1999

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↗
PubMed1999

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↗
PubMed1999

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↗
PubMed1999

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↗
PubMed1999

Safe electrical stimulation of the cochlear nerve at the promontory during functional magnetic resonance imaging.

The purpose of this study was to evaluate possibilities and technical risks for combining intended electrical stimulation of the cochlear nerve and functional magnetic resonance imaging (fMRI). Theoretical considerations and experiments indicate that fMRI can be performed safely during electrical stimulation. A nerve stimulator was developed with minimized length of electrical conductors, current limiting resistance, high inner impedance of a current source, radio frequency (RF)-shielding, and avoidance of ferromagnetic materials. This nerve stimulator transfers the optically encoded stimulating current signal via a fiber optic cable located near the area of stimulation. There, the optical signal drives an MRI-compatible current source. This set-up was tested with transtympanic electrical stimulation of the cochlear nerve at the promontory during an fMRI examination. No hazardous effects could be detected. The stimulation resulted in activation of the Heschl's gyrus. Compared to the conventional promontory testing this method may allow a more objective examination of cochlear implant candidates. Magn Reson Med 42:371-378, 1999.

Cochlear Nerve↗
PubMed1999

[Hepatocellular transplantation--from the beginning to clinical application].

Within the past 30 years hepatocyte transplantation has been developed in rodents for the cure of acute and chronic liver failure. Organ shortage and the enormous costs of orthotopic liver transplantation have promoted intensive research in transplantation of isolated hepatocytes. Transplanted syngeneic hepatocytes survive indefinitively in rodents, allowing correction of various inherited liver enzyme defects or enhancing recipient survival in experimentally induced acute liver failure. The clinical application of hepatocyte transplantation has been recently demonstrated in a young patient suffering from Crigler-Najjar syndrome type I, with successful long-term survival of allogeneic hepatocytes. This review reports the historical development and the published data on experimental and clinical hepatocyte transplantation.

Animals↗
PubMed1999

[Preoperative MR mammography in breast carcinoma. Effect on operative treatment from the surgical viewpoint].

INTRODUCTION: In a prospective study the diagnostic validity of magnetic resonance mammography (MRM) as well as its impact on the choice of the operative procedure in the treatment of breast cancer was examined. In 125 patients who were suspected of having breast cancer by clinical examination, ultrasound, and X-ray mammography, additional bilateral MRM was performed. Of special interest was the diagnostic potential of MRM with regard to multifocal, multicentric and contralateral lesions. METHODS: After a complete resection all lesions diagnosed by the various conventional methods were examined patho-histologically. In 112 patients, complete data were available to calculate the sensitivity and the specificity of each method as well as to correlate its results with the pathohistological findings. RESULTS: In 91 cases, a breast carcinoma was diagnosed by conventional methods, with a sensitivity/specificity of 73%/67% for clinical examination, of 58%/86% for ultrasound, and of 89%/20% for X-ray mammography. In this preselected series of patients with a prevalence of 81.25% the diagnosis established by the various methods was confirmed by MRM with sensitivity of 96.7% and specificity of 19%. Forty-six additional suspicious lesions were found only by MRM, of which 28 were malignant (25 multifocal or multicentric and 3 contralateral carcinomas), and 18 benign. The rate of false-positive MRM results was 18%. Due to the MRM findings, the therapeutic procedure was changed from breast preservation to mastectomy in 14.3%. CONCLUSION: Not only for the differential diagnosis of discrepant findings between X-ray mammography and ultrasound, but especially for the diagnosis of multifocal or multicentric lesions, MRM seems to be the method of choice. Consequently, MRM plays an important role in planning the operative procedure in breast cancer patients, especially in the context of breast preservation. To ensure optimal use of this new diagnostic tool high technical standards, proper expertise on the part of the examining radiologist, and effective cooperation among the involved disciplines (radiology, pathology, surgery) must be guaranteed.

Adult↗
PubMed1999

[Laparoscopic stoma technique].

Laparoscopic stoma creation may be performed as an independent intervention, in combination with local anorectal procedures or as a part of complex laparoscopic intestinal operations. With the exception of specialized methods to preserve continence, every type of stoma formation can be performed laparoscopically. Indications for laparoscopic fecal diversion do not differ from open surgery. Apparent advantages are the limitation of the laparotomy to the location of the stoma, rapid return of bowel function and less postoperative discomfort and morbidity, especially when intestinal diversion is required as an independent procedure. Previous surgery is not a contraindication for the laparoscopic procedure. However, dense adhesions may compromise the ability to identify the bowel segment to be exteriorized and require adhesiolysis. Therefore, the risk of intra- and postoperative complications and the frequency of conversions (reported between 4.1 and 15.7%) is increased in patients with previous surgery. The overall rate of complications reviewed in the literature, including stoma-related problems, seems to be similar or superior to conventional laparotomy. Still, laparoscopic enterostomies are not routinely performed in most institutions. Presently available data are limited and randomized trials have not been performed. We recommend the use of laparoscopic techniques for fecal diversion in patients with intestinal obstruction requiring palliative treatment and in patients with high probability for future abdominal surgery, e.g. in Crohn's disease.

Colostomy↗
PubMed1999

Determination of calcaneal ultrasound properties ex situ: reproducibility, effects of storage, formalin fixation, maceration, and changes in anatomic measurement site.

The objective of this study was to determine the reproducibility of ultrasonic bone properties with a system for measuring calcanei ex situ; the influence of changes of the measurement site; and the effects of fixation, storage, and maceration. We examined 14 fixed calcanei and 12 fresh bones. Ultrasonic measurements were performed ex situ after degassing, using an Achilles+ system and a special positioning device. The instrument precision was 0.16% for speed of sound (SOS), 1.4% for broadband ultrasonic attenuation (BUA), and 1. 8% for the stiffness index (SI). The short-term precision was 0.54%, 1.9%, and 2.8%, respectively. A defined shift of the measurement site (5 mm distal of the middle) led to unpredictable changes in ultrasound (US) properties (r = 0.65 for SOS, 0.82 for BUA, and 0.75 for SI). Embalment with 4% formalin/96% alcohol caused a systematic decrease in SOS, an increase in BUA, and a decrease in SI (mean = -12.7 units; P < 0.001), the effect increasing with time. However, values at 6 months of fixation and later were highly correlated with those in fresh specimens (r = 0.95 for the SI). Two weeks storage in degassed and normal solution had only modest effects on ultrasound properties. Maceration did not lead to a systematic increase or decrease of ultrasound variables, but introduced unpredictable changes (r = 0.64-0.94). We conclude that in comparative biomechanical studies it is feasible to measure calcaneal specimens embalmed in formalin/alcohol ex situ, if the primary interest is not in the absolute values but in the correlation with mechanical failure loads at other skeletal sites.

Aged↗