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Biomedical subjects

H Becker

Publications and source records attributed to H Becker.

At least 55 records · Page 3Linked to original sources
PubMed2001

Stress reduction through music in patients undergoing cerebral angiography.

We studied the influence of music on stress reaction of patients during cerebral angiography. We randomised 30 patients to a music or a control group. We measured stress hormones, blood pressure, heart rate and psychological parameters. Patients examined without music showed rising levels of cortisol in plasma, indicating high stress levels, while cortisol in patients examined with music remained stable. Systolic blood pressure was significantly lower listening to music. Patients with a high level of fear did appear to benefit particularly from the music.

Adult↗
PubMed2001

Intravascular stent placement for a fusiform aneurysm of the posterior cerebral artery: case report.

This article presents the case of a 45-year-old woman with a fusiform, broad-based, actually ruptured aneurysm of the posterior cerebral artery. The patient was successfully treated with stent placement and follow-up angiography demonstrated occlusion of the dome and the body of the aneurysm. Due to the limited neurosurgical treatment options, stent placement should be considered in patients with fusiform aneurysm of the posterior cerebral artery aneurysms.

Cerebral Angiography↗
PubMed2001

Genotype and phenotype of a new 2-bp deletion of hMSH2 at codon 233.

Germline mutations within mismatch repair genes, such as hMSH2, hMLH1, and hMSH6, have been shown to be the hallmark of the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome. The spectrum of tumors associated with mismatch repair gene defects and the possible relationship between genotype and phenotype are still unclear. Therefore, the spectrum of tumors and the possible genotype-phenotype relationship are still under discussion. Here, we report on a family with a new germline mutation in the hMSH2 gene with a 2-bp deletion at codons 232 and 233 leading to a frame shift and a stop at codon 254. Accordingly, immunohistochemistry revealed loss of hMSH2 expression in colorectal carcinomas of three affected family members. In this one family, there was a high penetrance. Interestingly, mutational screening of the family revealed a high penetrance of the mutation affecting four of five tested people at risk, with a high mortality rate and a trend toward lower age of onset in subsequent generations. Finally, a metachronous breast cancer in one patient turned out to be a tumor unrelated to microsatellite instability phenocopy, i.e., a sporadic tumor unrelated to HNPCC that expressed the hMSH2 gene and did not show any microsatellite instability.

Adolescent↗
PubMed2001

Central mesh recurrence after incisional hernia repair with Marlex--are the meshes strong enough?

The use of biomaterial meshes in the repair of incisional abdominal wall hernias is now widely accepted internationally. The introduction of synthetic meshes to achieve tension-free repair has led to a satisfactory reduction in the recurrence rate to less than 10%. However, the use of such biomaterials can result in the occurrence of undesirable complications such as increased risk of infection, seromas, restriction of the abdominal wall and failure caused by mesh shrinkage. Additionally, at the time of writing there is much discussion concerning the potential risk of a persistent foreign body reaction directly associated with the meshes with regard to possible malignant transformation. As such, the trend seems to be toward the use of lighter meshes utilizing less non-absorbable material. One particular novel mesh theoretically capable of guaranteeing the necessary mechanical stability uses 70% less biomaterial. Against this background, we report a central mesh recurrence through the mesh following incisional hernia repair with a Marlex mesh. To our knowledge, this is the first description of a central mesh recurrence, and we discuss a possible mechanism with particular emphasis on the required abdominal wall forces both physiologically and after incisional hernia repair.

Elasticity↗
PubMed2001

Biosynthesis of the hemi- and monoterpene moieties of isoprenyl phenyl ethers from the liverwort Trichocolea tomentella.

The incorporation of 13C labelled glucose into trichocolein, deoxytomentellin, trans-phytol and stigmasterol has been studied in axenic cultures of the liverwort Trichocolea tomentella. Quantitative 13C NMR spectroscopic analysis of the resulting labelling patterns showed that the isoprene units of the hemi- and monoterpenoid moieties and the diterpene phytol are derived from the methylerythritol phosphate pathway, whereas the isoprene units of stigmasterol are built up via the mevalonic acid pathway. These results indicate the involvement of both IPP biosynthetic pathways in different cellular compartments. A new, hydroperoxy geranyl phenyl ether derivative is also described.

Ethers↗
PubMed2001

Biosynthesis of a hopane triterpene and three diterpenes in the liverwort Fossombronia alaskana.

The biosynthesis of the triterpene 22-(30)-hopene-29-acid and the diterpenes 7,17-sacculatadiene-11,12-dial (sacculatal), trans-phytol and a new neoverrucosane-type diterpenoid (5-oxo-neoverrucos-(13)-ene) was studied by incorporation of [1-13C]-labelled glucose into axenic cultures of the artic liverwort Fossombronia alaskana. Quantitative 13C NMR spectroscopic analysis of the resulting labelling patterns showed that the isoprene units of the triterpene are derived from the mevalonic acid pathway, whereas the isoprene units of the diterpenes are built up via the methylerythritol phosphate pathway.

Diterpenes↗
PubMed2001

Polymer based micro-reactors.

In this paper, we describe the fabrication technologies necessary for the production of polymer-based micro-fluidic devices. These technologies include hot embossing as a micro-structuring method as well as so-called back-end processes to complete the micro-devices. Applications such as capillary electrophoresis, micro-mixers and nanowell plates are presented.

Bioreactors↗
PubMed2001

[Quantitative multi-slice imaging of perfusion of the brain].

AIM: To develop an MR pulse sequence that allows the determination of the quantitative perfusion of the brain by imaging the passage of a contrast agent bolus with high temporal and spatial resolution. METHODS: An EPI sequence, EPIDET (Echo Planar Imaging using Different Echo Times), was developed that allows the acquisition of different slices at different echo times. The passage of a contrast agent bolus was recorded in a slice through the large brain feeding arteries at a short echo time (TE1 = 17 ms), while brain parenchyma was imaged in up to nine additional slices at a long echo time (TE2 = 34 ms). RESULTS: The different echo times allowed the determination of the arterial input function (signal decrease to 32%-59% of baseline intensity) and gave a sufficient signal reduction (14-22%) for reliable quantification of perfusion in brain parenchyma. CONCLUSIONS: The combination of different echo times of the DUAL-FLASH sequence and the multislice capability of EPI sequences in the EPIDET sequence enables the quantification of multi-slice perfusion examinations. Compared to the DUAL-FLASH sequence EPIDET improves spatial and temporal resolution.

Blood-Brain Barrier↗
PubMed2001

[Patient-ventilator interaction during noninvasive pressure supported spontaneous respiration in patients with hypercapnic COPD].

BACKGROUND: Noninvasive pressure support ventilation (NPSV) demands triggering with each breath. This study investigates the effects of NPSV via face mask on breathing pattern, ventilation and respiratory muscle loading in patients with hypercapnic stable COPD. METHODS: 7 patients (age 66 +/- 9 years; FEV1 43 +/- 13% predicted; PaO2 52 +/- 19 mmHg; PaCO2 58 +/- 12 mmHg) were included. The physiologic variables were evaluated during spontaneous breathing and at the end of a 60 minutes period with NPSV. Inspiratory positive airway pressure (IPAP) and expiratory positive airway pressure (EPAP) were adjusted to 12-14 cm H2O and 3 cm H2O, respectively. Respiratory muscle activity was measured as esophageal and transdiaphragmatic pressure time product (PTPes and PTPdi). RESULTS: Non-triggering was observed only occasionally. Compared to unsupported spontaneous breathing NPSV improved ventilation: PaCO2 was reduced from 58 +/- 11 mmHg to 50 +/- 14 mmHg (p +/- 0.05). Respiratory muscles were unloaded by 30% (p +/- 0.05). Breathing frequency and breathing pattern did not change. CONCLUSIONS: In patients with hypercapnic stable COPD NPSV effectively recognizes and supports breathing efforts. As a result ventilation is improved and respiratory muscles are unloaded.

Aged↗
PubMed2001

[Ultrasound diagnosis of Meckel diverticulitis in adults].

Meckel's diverticulitis is a rare disease. In addition to physical examination, abdominal ultrasound can help to pinpoint the diagnosis. By presenting a case report we would like to demonstrate the typical ultrasonographic findings in acute Meckel's diverticulitis and differentiate it from acute appendicitis. A 60-year-old patient was admitted to our hospital with the diagnosis of acute appendicitis. Abdominal ultrasound was performed and a blind ending, liquid-filled segment of small bowel in the right lower quadrant of the abdomen found. This segment was not compressible, no peristalsis was evident, nor was there any anatomical association with the cecum. Locally we found free fluid and hints of inflamed mesenteric fatty tissue. A perforated Meckel's diverticulum was diagnosed and confirmed intraoperatively. The major ultrasonographic difference between an inflamed Meckel's diverticulum and acute appendicitis is its anatomical location. In contrast to the appendix there is no association with the cecum. A diameter of up to 40 mm and a well-defined wall of small bowel with 3 definite layers visible by ultrasound may help to distinguish between a Meckel's diverticulum and the appendix.

Acute Disease↗
PubMed2001

[CAS-System MKM(R): use and results in lateral skull base surgery].

BACKGROUND: Computer assisted surgery has reached an advanced stage of development and offers new possibilities in daily surgical procedures. METHODS: The MKM(R) - is a navigation system fitted with a laser-guided, autofocus-microscope for referencing purposes. The coordinates can be set using various marker systems and a special workstation is used for preoperative planning. It is possible to add landmarks and display them in the surgeon's eyepiece. The clinical integration, the time required for the use of the navigation system and the intraoperative accuracy of the system were evaluated on the basis of 136 lateral skull base procedures. RESULTS: The degree of accuracy is determined by the type, amount and positioning of markers. The adjustment of reference points should be carried out following macrosurgery in order to avoid shifting factors. For an additional increase in accuracy, an improvement in the spatial resolution of the CT scans is required, with a section thickness of 1 mm and a pixel size of 0.5mm. The bone-anchored structures of the temporal bone do not underlie shifting or extensive intraoperative swelling. Skull base surgery is, therefore, ideally suited for the application of CAS. We found that registration was accurate to less than 1 mm (0.68 mm +/- 0.17 mm) and that the MKM(R) system made an additional contribution to surgical safety by identifying important structures. CONCLUSIONS: A practical accuracy found to be approximately one millimetre suggests that the non-invasive referencing system may be effective, accurate and useful for computer assisted identification of vital structures. We expect navigation systems to improve the quality and reduce the risks of surgical intraventions.

Adult↗
PubMed2001

[Interphase cytogenetics with DNA-probes for chromosome 8 to detect circulating tumor cells in breast cancer patients].

The detection of micrometastases in the bone marrow or peripheral blood of cancer patients is increasingly used for a more sensitive tumor staging and prognostication. The potential value of the currently used techniques for the detection of epithelial antigens by RT-PCR or immunohistochemistry in respect of specificity is currently controversially discussed. In the present study we demonstrate a new approach which enables the direct visualization of the tumor specific alteration of chromosome 8 in circulating tumor cells. We have therefore studied breast cancer patients with various tumor stages and tried to determine the frequency of circulating tumor cells in the peripheral blood by using interphase cytogenetics for chromosome 7 and 8. Imprints of primary breast cancers and cytospins with circulating tumor cells of corresponding patients were studied in a blinded fashion. The blood samples were generated by immunomagnetic enrichment of circulating tumor cells from peripheral blood by ferrofluid and centrifugation onto cover slips. These cytospins were then hybridized with centromer probes 7 and 8. After analyzing 27 patients with benign as well as malignant breast tumors we can demonstrate that the chromosomal pattern between malignant tumor and corresponding circulating tumor cells is identical. Furthermore, the detection of circulating tumor cells directly correlates with the primary tumor stage. We did not find any cells with chromosome 8 alterations in the patients with benign disease. Surprisingly, even in early breast cancers (T1N0) interphase cytogenetics identified circulating tumor cells in 2 out of 4 patients. In conclusion, interphase cytogenetics represent a non-invasive, sensitive and specific assay for the direct visualization of circulating tumor cells in the peripheral blood. The prognostic value of these findings remains to be further evaluated in larger prospective studies.

Breast Neoplasms↗
PubMed2001

Proportional positive airway pressure: a new concept to treat obstructive sleep apnoea.

Proportional positive airway pressure (PPAP) was designed to optimize airway pressure for the therapy of obstructive sleep apnoea (OSA). In a randomized crossover prospective study, the clinical feasibility of PPAP and its immediate effects on the breathing disorder and sleep in comparison with continuous positive airway pressure (CPAP) was evaluated. Twelve patients requiring CPAP therapy underwent CPAP and PPAP titration in a random order. Obstructive and mixed respiratory events could be completely abolished with both forms of treatment. This efficacy could be achieved at a significantly lower mean mask pressure during PPAP titration (8.45+/-2.42 cmH2O) compared to CPAP (9.96+/-2.7 cmH2O) (p=0.002). The mean minimal arterial oxygen saturation (Sa,O2) (82.8+/-6.5%) on the diagnostic night increased significantly (p<0.001) to an average Sa,O2 of 93.35+/-1.71% and 93.19+/-2.9% during CPAP and PPAP titration. Total sleep time, slow wave sleep and rapid eye movement (REM) sleep increased significantly by the same amount during both CPAP and PPAP titration (p<0.001), while sleep stage nonrapid eye movement (NREM) 1 and 2 decreased. Six patients preferred the PPAP titration night, four patients did not have a preference, and two patients preferred CPAP. The present data show that proportional positive airway pressure is as effective as continuous positive airway pressure in eliminating obstructive events and has the same immediate effect on sleep. The lower average mask pressure during proportional positive airway pressure implies potential advantages compared to continuous positive airway pressure. Proportional positive airway pressure presents a new effective therapeutic approach to obstructive sleep apnoea.

Adult↗
PubMed2001

Lack of methemoglobinemia with flutamide.

OBJECTIVE: To determine whether the nonsteroidal antiandrogenic drug flutamide is a clinically relevant inducer of methemoglobinemia in patients with prostatic cancer. METHODS: Fifty consecutive outpatients with prostatic cancer stage D2 entered the study (age 71.1 +/- 7.3 y). Five patients were lost to follow-up; the remaining 45 patients received the recommended oral dose of flutamide 250 mg three times daily. Total hemoglobin (Hb) and methemoglobin (Met-Hb) concentrations were measured on varying days using an ultraviolet/visible-spectrophotometric method with an intra- and interday variability < 8%. In 12 patients, Met-Hb was analyzed before initiating flutamide therapy and after therapy was begun. RESULTS: On average, 2.6 venous blood samples per patient were analyzed with a mean Met-Hb concentration of 1.9% of total Hb. Mean concentrations of > or = 3% were detected in only six patients (13%). The data from 12 patients evaluated before and after initiating flutamide therapy were without significantly different changes. During the study period, no clinical signs of methemoglobinemia were reported or observed. CONCLUSIONS: This study found no clinically relevant increase of Met-Hb concentrations in elderly patients with prostatic cancer during chronic treatment with flutamide. However, clinicians should be aware of the very rare possibility of flutamide-induced methemoglobinemia.

Aged↗
PubMed2001

Using intranasal midazolam spray to prevent claustrophobia induced by MR imaging.

OBJECTIVE: Up to 37% of patients undergoing MR imaging examinations experience moderate to severe levels of anxiety that necessitate the termination of the procedure in 5-10% of patients. Although the clinical use of MR imaging has increased, effective procedures to handle claustrophobia are lacking. We evaluated the effectiveness of intranasally administered midazolam spray in preventing claustrophobic responses of patients undergoing MR imaging. SUBJECTS AND METHODS: Fifty-four patients scheduled for MR imaging were included in this prospective study. Anxiety and sedation of patients were evaluated before drug administration, immediately before MR imaging, and at the end of the procedure. The Spielberger State-Trait Anxiety Inventory, the visual analogue scale of anxiety, and a five-point sedation scale were used. Half the patients received intranasal spray applications of 4 mg midazolam, whereas the other patients received a placebo, in a randomized, double-blind study design (six sprayings of 0.5% midazolam solution or NaCl 0.9%, respectively). The intensity of the sensation of burning of the nasal mucosa was rated by patients using a three-point scale (no, slight, or strong burning). The quality of scan images was evaluated by a radiologist using a five-point scale (0 = extremely poor, 5 = excellent). RESULTS: No cancellations occurred with patients who received midazolam, whereas four of 27 patients receiving placebo panicked and terminated the scanning procedure. The initial anxiety and sedation scores did not differ between the groups. Patients who received midazolam spray were more sedated and less anxious immediately before entering the MR scanner and reported a more intense slight transient burning of the nasal mucosa than those in the placebo group. The quality of the MR image was higher in the midazolam group. CONCLUSION: A sizeable reduction in MR imaging-related anxiety and improved MR image quality were seen with patients who received intranasal midazolam spray. With the exception of transient burning of the nasal mucosa, no adverse effects were reported. This simple and safe method is useful in sedating patients for MR imaging and other minor procedures.

Administration, Intranasal↗