Biomedical subjects

A Maier

Publications and source records attributed to A Maier.

At least 55 records · Page 3Linked to original sources

PubMed2000

[Endoanal magnetic resonance tomography in fecal incontinence].

PURPOSE: Within the recent years several studies have been performed to determine the value of endoanal magnetic resonance imaging (MRI) in faecal incontinence. METHODS: MRI is performed using a 0.5-1.5 T unit. A surface coil with a maximum diameter of 19 mm is placed in the anal canal. T2* 3D gradient-echo-sequences and T2-weighted turbo-spin-echo sequences in coronal, axial und sagittal orientation are acquired. RESULTS: Compared to endoanal ultrasound (EUS), which is the gold standard for diagnosis in faecal incontinence, endoanal MRI is better in visualization of the external sphincter. The accurate delineation of the external sphincter has led to the possibility to evaluate sphincter atrophy. Preliminary results have shown, that endoanal MRI has an accuracy of 90-95% in the demonstration of lesions in the external sphincter. In detection of lesions of the internal sphincter EUS is still superior to endoanal MRI. CONCLUSION: EUS and endoanal MRI are currently the optimal imaging techniques for faecal incontinence, with the advantage of detecting external sphincter atrophy with endoanal MRI.

Anal Canal↗

PubMed2000

Radical surgical therapy of abdominal cystic hydatid disease: factors of recurrence.

A series of 74 consecutive patients (48 women, 26 men) were operated for abdominal hydatid disease between June 1949 and December 1995. The patients ranged in age from 15 to 81 years (median 49 years). In 69 cases only the liver was affected; two patients had concomitant extrahepatic disease (one spleen, one spleen and lung), and 3 had cysts in the spleen only. Cysts were multiple in 11 patients and calcified in 24. Conservative surgical procedures were used for 22 cysts in 20 patients [open partial (n = 3), open total (n = 6), closed total cystectomy (n = 9), marsupialization (n = 2), drainage (n = 2)] and radical surgical procedures for 72 cysts in 54 patients [pericystectomy (n = 41), wedge liver resection or hemihepatectomy (n = 25), splenectomy (n = 5), radical resection of a lung cyst (n = 1)]. Altogether 37 patients (50%) were given perioperative antihelmintic chemotherapy with mebendazole (18 patients) or albendazole (19 patients). Operative mortality rates were 5.0% after conservative surgery and 1.8% after radical surgery. Morbidity rates were 25.0% following conservative surgery and 24.1% following radical surgery. Antihelmintic therapy was well tolerated by all but five patients. All side effects were entirely reversible. Among the 74 patients, 60 (81.0%) were available for long-term follow-up (median 7.2 years; range 2.0-47.0 years). Recurrence of disease was seen in 9 of 60 patients at an interval of 3 months to 20 years from the first operation. The rate of recurrence was significantly lower after radical surgical procedures (p = 0.03) and after closed removal of the cyst (p = 0.04).

Adolescent↗

PubMed2000

Four-year experience with pleural abrasion using a rotating brush during video-assisted thoracoscopy.

BACKGROUND: Due to the high recurrence rate in primary spontaneous pneumothorax (PSP), surgical therapy is currently a well-accepted method of treating this condition. There is no general agreement about the best time for surgical intervention (i.e., after the first or second episode) or the optimal surgical approach,--i.e., tube thoracocenteses, thoracotomy, or video-assisted thoracoscopy (VATS) with or without pleurectomy or pleurodesis. The aim of this study was to verify the efficacy of VATS and mechanical brush pleurodesis using a rotating electrical brush system. METHODS: We treated 47 patients with PSP between June 1993 and June 1997. Follow-up ranged from 20 to 56 months. There were 38 male and nine female patients with a mean age of 26 years. Emergency thoracocenteses due to tension pneumothorax became necessary in three patients. All patients were treated by VATS and mechanical brush pleurodesis. Wedge resection was done if bullae or blebs were present (68.1%). RESULTS: Operating time was 20-60 min (mean, 35). There were no intraoperative complications and no conversions to conventional surgery. In the first few postoperative days, postoperative pain was controlled with nonsteroidal antirheumatic drugs and additional morphines. Drainage time was 3-7 days (mean, 4). Hospitalization time was 4-8 days (mean, 5). The recurrence rate was 2.1% (one patient). No postoperative bleeding or wound infection occurred in any of our patients. CONCLUSIONS: VATS combined with mechanical brush pleurodesis using the electrical brush system is a highly effective and safe treatment for patients with recurrent primary spontaneous pneumothorax.

Adolescent↗

PubMed2000

Palliation of advanced esophageal carcinoma by photodynamic therapy and irradiation.

BACKGROUND: We wanted to determine the role of photodynamic therapy in a multimodal approach for the treatment of patients with advanced cancer of the esophagus. METHODS: We reviewed the cases of 119 patients with nonresectable esophageal carcinoma who underwent endoluminal palliation. Twenty-one patients required initial dilation and tumor obliteration with a neodymium: yttrium-aluminum-garnet laser prior to therapy. Forty-four patients received photodynamic therapy followed by brachyradiotherapy, and 75 patients were treated with brachyradiotherapy. In both groups, some patients also received external-beam irradiation. RESULTS: Photodynamic therapy produced a significant difference in relieving stenosis caused by tumor stenosis (mean, 6.6 mm; p = 0.0000). The dysphagia score improved by one to three levels in all patients, with a significant difference in favor of PDT (p = 0.0003). The mean number of overall treatment sessions was four (range, one to seven). The rate of major complications was 9.2%. Four esophageal perforations occurred, three after intervention and one spontaneously 5 months later. Four esophagorespiratory tract fistulas developed several months after combined PDT and irradiation. The mean overall survival was 7.7 months, and analysis of variance revealed a significant difference in favor of PDT and external-beam irradiation (p = 0.0129 and p = 0.0001, respectively). CONCLUSIONS: Photodynamic therapy has been shown to be an effective palliative treatment of advanced esophageal cancer. However, proper patient selection is necessary to prevent serious complications.

Adenocarcinoma↗

PubMed2000

The epidemiology of fractures of the distal femur.

Between 1980 and 1989, reports on 2,165 fractures of the distal part of the femur (1,051 women and 1,114 men) were collected by AO Documentation and are analyzed in the present paper. The number of fractures showed a bimodal pattern with a marked variation in the number of fractures in relation to gender and age. A larger prevalence of fractures was observed either in young men (about 20 years old, traffic or sport) and in old women (about 70, fall at home, osteoporosis).

Accidental Falls↗

PubMed2000

Prevention of malunions in the rotation of complex fractures of the distal femur treated using the Dynamic Condylar Screw (DCS): an anatomical graphic analysis using computed tomography on cadaveric specimens.

The AO ASIF dynamic condylar screw is a popular method for the treatment of severe distal femoral fractures. Two methods of application have been presented by the AO group, one in the AO manual and the other in the teaching video tapes. The small difference in the techniques suggested that one of these methods might present a risk of rotational malunion in cases of severe comminuted fractures. The question of determining which method was less appropriate was investigated on human cadaveric specimens using a graphic analysis of computed tomograms. We found disadvantages for both methods and propose a third method combining the advantages of the two original methods.

Adult↗

PubMed2000

Morphological variability and specializations in bovine extraocular muscle spindles.

Bovine extraocular muscles were examined to determine whether the structure of their muscle spindles was notably different from those commonly encountered in mammalian limb muscles. Extraocular muscle spindles on the whole were shorter, and intrafusal fiber counts/spindle were more variable than in somatic muscles. No pronounced nuclear bags were seen in intrafusal fibers. Based on cross-sectional areas, intrafusal fibers in extraocular muscles could be loosely categorized as small or large types. Small fibers expressed more neonatal/fast myosin heavy chain and less embryonic myosin heavy chain than large fibers. When incubated for myosin ATPase, about 70% of the large fibers and 15% of the small fibers in spindles presented profiles that were characteristic of type I extrafusal fibers, and not of nuclear bag or nuclear chain fibers. The ratio of number of small intrafusal fibers to number of large intrafusal fibers in extraocular spindles was on average greater than the ratio of nuclear chain fibers to nuclear bag fibers that is typical for limb spindles of rodents and cats. Structural modifications at muscle spindle sensory regions, extrafusal-like fibers and intrafusal-like fibers with few equatorial nuclei and many myofibrils, may produce distinct afferent signals that are appropriate for sensorimotor integration in the specialized extraocular muscles.

Animals↗

PubMed2000

Combined photodynamic therapy and hyperbaric oxygenation in carcinoma of the esophagus and the esophago-gastric junction.

OBJECTIVES: The photochemical reaction of photodynamic therapy (PDT) depends on the presence of molecular oxygen. Due to anoxic regions in tumor tissue and vascular shutdown during PDT the efficiency is limited. Therefore, the use of hyperbaric oxygen which increases the oxygen in tumor tissue, as well as the amount of singlet oxygen, may enhance the efficiency of PDT. PATIENTS AND METHODS: After diagnostic work-up, photosensitization was carried out with a hematoporphyrin-derivate 2 mg/kg BW 48 h prior to PDT. The light dose was calculated as 300 J/cm fiber tip. Thirty-one patients were treated by PDT alone and 44 patients received PDT under hyperbaric oxygen at a level of two absolute atmospheric pressure. RESULTS: Improvement regarding stenosis-diameter could be obtained in both treatment arms with no significant difference (P=0.82). The dysphagia-score and tumor-length also decreased in both groups and showed a significant difference in favour of the PDT/HBO-group (P=0. 0064 and P=0.0002, respectively). The median overall survival for the PDT-group was 7 months and for the PDT/HBO-group 12 months (P=0. 0098). CONCLUSION: According to this prospective non-randomized study, combined PDT/HBO represents a new approach in the treatment of esophageal and cardia cancer which appears to have enhanced the efficiency of PDT.

Aged↗

PubMed2000

Computed tomography or ultrasonically guided pigtail catheter drainage in multiloculated pleural empyema: a recommended procedure?

OBJECTIVES: The role of image-guided pigtail catheter drainage in the treatment of pleural empyema is associated with different outcomes, dependent on the stage of the disease. No agreement concerning its use exists. METHODOLOGY: Fourteen patients at a fibropurulent stage of pleural empyema initially treated with computed tomography (CT) or ultrasonically guided pigtail catheter drainage were reviewed. All patients were admitted with clinical symptoms of sepsis. Chest X-ray, CT scan and/or ultrasonography and thoracentesis with biochemical examination revealed multiloculated pleural empyema. Despite the diagnosis of multiloculated empyema, CT or ultrasonically guided pigtail catheter drainage was performed. However, septic symptoms deteriorated and all cases proceeded to thoracotomy with decortication. RESULTS: Image-guided drainage failed in all patients. Septic symptoms disappeared within 24-48 h after decortication. The patients recovered without sequela, were discharged 6-15 days (mean: 9.2 days) postoperatively and were able to return to normal physical activity. CONCLUSIONS: Computed tomography or ultrasonically guided pigtail catheter drainage can not be recommended in the case of a fibropurulent stage of empyema thoracis.

Adult↗

PubMed2000

Review of severe osteoradionecrosis treated by surgery alone or surgery with postoperative hyperbaric oxygenation.

We reviewed 41 patients with osteoradionecrosis of the mandible. Each patient was treated by radical resection followed by external beam irradiation. The diagnosis of infected osteoradionecrosis was confirmed clinically, radiologically, and histologically. After operation had failed, 20/41 were given hyperbaric oxygen (HBO) as in 'salvage' treatment. Daily sessions of HBO 2.5 ATA for 60 minutes (mean: 29 sessions) were given. The other 21 patients were treated by operation and antibiotics alone. HBO group (n = 20): The overall success rate for HBO after operation had failed was 13/20. Repeated debridement as first-line treatment followed by postoperative HBO was successful in 12/19. In seven of 19 patients, partial mandibulectomy and microvascular transplantation were required as second-line treatment, and this was successful in five. Primary partial mandibulectomy and microvascular transplantation followed by HBO was successful in 1 patient. Non-HBO group (n = 21): Repeated debridement was successful in 10/11 patients. Partial mandibulectomy was required as second-line treatment in the remaining one. In the other 10, partial mandibulectomy and microvascular transplantation were successful as first-line treatment in four. In the remaining six, further surgical intervention became necessary and were successful for 5-17 months (mean: 13). With a success rate of 13/20, we do not recommend HBO for the treatment of osteoradionecrosis.

Aged↗

PubMed2000

Does hyperbaric oxygen enhance the effect of photodynamic therapy in patients with advanced esophageal carcinoma? A clinical pilot study.

BACKGROUND AND STUDY AIMS: Experimental studies have shown that the cytotoxicity of porphyrins and related substances is mediated mainly by singlet oxygen and that hypoxic cells are less affected by porphyrins and light. In a clinical pilot study we assessed the use of photodynamic therapy (PDT) under hyperbaric oxygen (HBO), compared with PDT under normobaric conditions, in patients with advanced esophageal carcinoma. PATIENTS AND METHODS: After diagnostic work-up and staging, photosensitization in all patients was carried out using hematoporphyrine derivate (HpD) (2 mg/kg bodyweight 48 hours prior to PDT). We then applied light at 630 nm (KTP-Nd: YAG laser with DYE box) at dose of 300 J/cm, delivered by a fiber with a radial light-diffusing cylinder (length 1 cm), inserted through the biopsy channel of the endoscope. Of the patients, 14 (12 with stage III cancers, and two with stage IV cancers) were treated by PDT alone, and 17 patients (15 with stage III cancers, and two with stage IV cancers) received PDT under HBO at a level of 2 absolute atmospheric pressures (ATA). Transcutaneous PO2 levels of 500-750 mm Hg under HBO, compared with transcutaneous PO2 levels of 60-75 mm Hg under normobaric conditions, were measured. RESULTS: Improvements regarding dysphagia and stenosis diameter were obtained in both treatment arms with no significant differences (P = 0.36 and 0.14, respectively). The tumor length also decreased in both groups and showed a significant difference in favour of the PDT/ HBO group (P = 0.002). Kaplan-Meier statistics showed median overall survival for the PDT group and the PDT/HBO group as 7.0 and 12 months respectively. The 12-month survival rate was 28.6% for the PDT group and 41.2% for the PDT/HBO group. Logrank test showed a difference in survival in favor of the PDT/HBO group (P = 0.059). No major treatment-related complication occurred, and the 30-day mortality rate was 0%. CONCLUSIONS: Combined PDT/HBO represents a new approach in the treatment of esophageal cancer which, in this pilot study, appears to have enhanced the efficiency of PDT.

Adenocarcinoma↗

PubMed2000

[Spectroscopic imaging (1H-2D-CSI) of the prostate: sequence optimization and correlation with histopathological results].

PURPOSE: Methodological optimization of a 1H MR spectroscopic imaging sequence (1H-2D-CSI) and evaluation of its potential to diagnose prostate cancer as validated by histopathological maps. METHODS: The prostates of 18 patients were evaluated by 1H-MR-CSI (voxel dimension: 1 cm3) at 1.5 Tesla. This sequence was additionally combined with a frequency selective fat suppression. RESULTS: It was possible to distinguish prostate carcinoma from prostate hyperplasia spectroscopically by the ratio of citrate/(choline + creatine). Differentiation of high-grade prostatic intraepithelial neoplasia (PIN, high-grade) from prostate carcinoma was not unambiguously possible. Prediction of tumor differentiation was not possible by the ratio of citrate/(choline + creatine) by our maximum spatial resolution of 1 cm3. CONCLUSION: 1H-2D-CSI is suitable for tumor detection. Tumor differentiation was not possible with the spatial resolution used.

Aged↗

PubMed2000

Pleural effusions and sera from patients with benign or malignant diseases.

In pleural effusions and sera from 66 patients copper and zinc were quantified by inductively coupled argon plasma-mass spectrometry after mineralizations in a closed-pressurized microwave unit with a mixture of concentrated nitric acid and 30% hydrogen peroxide. Total protein, pH, leukocyte count, lactate dehydrogenase, glucose, C-reactive protein, ceruloplasmin, and alpha1-antitrypsin were determined in many of the effusions. All but four effusions had concentrations of copper (range 58-1720 microg/kg) and zinc (range 27-1001 microg/kg) that were lower than the concentrations in the corresponding sera. Very high concentrations of zinc (1930-6470 microg/kg) were characteristic for thoracic empyemata. In the scatterplots of serum copper versus effusion copper, serum zinc versus effusion zinc, and serum copper/effusion copper versus serum zinc/effusion zinc no clearly delineated regions were noticeably useful for identifying malignant effusions. Similar plots of the concentrations of copper or zinc versus the eight clinical laboratory parameters or plots of clinical parameter versus clinical parameter failed to be of diagnostic value. Statistically highly significant correlations (p < or = 0.05, n > 45, r2 > 0.25) were observed for 9 of 28 pairs of the clinical parameters, for total protein and copper in the effusions and zinc in the effusions and for ceruloplasmin and copper in the effusions. Among the patients suffering from benign or malignant effusions, 52% had zinc concentrations in the sera below the low limit of the normal range (600 microg/kg). Supplementation of such patients with zinc should be considered.

Adolescent↗

PubMed2000

Concentrations of copper, zinc, manganese, rubidium, and magnesium in thoracic empyemata and corresponding sera.

In this study, a number of selected trace elements and clinically relevant parameters were compared between thoracic empyemata and the corresponding sera for a better understanding of the trace element distribution between these two compartments. Serumempyema pairs were obtained from 13 patients and quantified for selected and essential trace elements, namely copper (Cu), zinc (Zn), manganese (Mn), rubidium (Rb), and magnesium (Mg), by inductively coupled plasma-mass spectrometry (ICP-MS). In addition, the concentrations of the following clinical laboratory parameters were analyzed by standard methods: total protein, leukocyte count, lactate dehydrogenase, glucose, pH, and the C-reactive protein. Individual concentrations of the elements determined in the empyemata were frequently higher than in pleural effusions of any other benign or malignant condition except for Cu. Serum Cu exceeded the normal range (600-1400 microg/kg) in 6 out of 13 patients (median 1410 microg/kg). In the empyemata, Zn concentrations (median 2000 microg/kg) were characteristically higher than in the sera (median 450 microg/kg) and exceeded the upper limit for serum (1200 microg/kg) in 8 of the 13 patients. Manganese concentrations in the empyemata (median 2.7 microg/kg) were also higher compared to corresponding sera, although they stayed within the limits considered normal for serum of healthy adults (upper limit 2.9 microg/kg). Rubidium was also moderately higher in most empyemata (median 290 microg/kg) and exceeded the upper limit for serum (560 microg/kg) in two patients. The median concentration of the essential element magnesium was higher in the empyemata (23 mg/kg) than in the sera (21 mg/kg). However, all serum Mg concentrations except three remained within the normal range (17-22 mg/kg). Removal of large amounts of empyematous fluid may deprive the body of trace elements and can cause suboptimal or deficient trace element status and homeostasis. Recuperation will be accelerated by compensatory supplementation of trace elements. Therefore, selective medication with adequate trace element compounds in patients with thoracic empyema can be generally recommended for zinc. The other elements need not necessarily be monitored or substituted, because of their stable concentrations in the serum. Rb may have a biological impact, but deficiency symptoms in man are not clearly defined.

Aged↗

PubMed2000

Disruption of dioxin-inducible phase I and phase II gene expression patterns by cadmium, chromium, and arsenic.

Recent work suggesting that cellular oxidative stress exerts an inhibitory effect on aromatic hydrocarbon receptor (AHR)-dependent gene expression led us to test the hypothesis that pro-oxidant environmental pollutants might alter the induction of detoxification genes by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an AHR ligand. We found that, in mouse hepatoma Hepa-1 cells, TCDD-inducible cytochrome P450, Cyp1a1, and nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase (Nqo1) mRNA accumulation were differentially affected by cadmium (Cd(2+)), chromium (Cr(6+)), and arsenic (As(3+)). Cadmium or arsenic did not change Cyp1a1 mRNA levels but did enhance TCDD-inducible levels of Nqo1 mRNA, an effect that paralleled the ability of these metals to activate a beta-galactosidase gene reporter system regulated by an electrophile response promoter element. Chromium inhibited mRNA accumulation for both Cyp1a1 and Nqo1. Manipulation of cellular thiol status did not modify the response to combined chromium-TCDD exposure, suggesting that the response was not caused by oxidative stress. Chromium did not block DNA-binding competence of the AHR and did not have an effect on mRNA stability, but it inhibited Cyp1a1 gene transcription and the expression of an AHR-dependent luciferase reporter. These data indicate that coexposure to pro-oxidant metals and AHR ligands, which is common in the environment, can disrupt the regulation of phase I and phase II detoxification genes, leading to imbalances in gene expression that may have important consequences for the toxicity of complex mixtures.

Animals↗

PubMed1999

Direct induction of cyclin D2 by Myc contributes to cell cycle progression and sequestration of p27.

Ectopic expression of Myc induces Cdk2 kinase activity in quiescent cells and antagonizes association of p27(kip1) with Cdk2. The target gene(s) by which Myc mediates this effect is largely unknown. We now show that p27 is rapidly and transiently sequestered by cyclin D2-Cdk4 complexes upon activation of Myc and that cyclin D2 is a direct target gene of Myc. The cyclin D2 promoter is repressed by Mad-Max complexes and de-repressed by Myc via a single highly conserved E-box element. Addition of trichostatin A to quiescent cells mimics activation of Myc and induces cyclin D2 expression, suggesting that cyclin D2 is repressed in a histone deacetylase-dependent manner in quiescent cells. Inhibition of cyclin D2 function in established cell lines, either by ectopic expression of p16 or by antibody injection, inhibits Myc-dependent dissociation of p27 from Cdk2 and Myc-induced cell cycle entry. Primary mouse fibroblasts that are cyclin D2-deficient undergo accelerated senescence in culture and are not immortalized by Myc; induction of apoptosis by Myc is unimpaired in such cells. Our data identify a downstream effector pathway that links Myc directly to cell cycle progression.

3T3 Cells↗

PubMed1999

Proportions of slow myosin heavy chain-positive fibers in muscle spindles and adjoining extrafusal fascicles, and the positioning of spindles relative to these fascicles.

Chicken leg muscles were examined to calculate the percentages of slow myosin heavy chain (MHC)-positive fibers in spindles and in adjacent extrafusal fascicles, and to clarify how the encapsulated portions of muscle spindles are positioned relative to these fascicles. Unlike mammals, in chicken leg muscles slow-twitch MHC and slow-tonic MHC are expressed in intrafusal fibers and in extrafusal fibers, suggesting a close developmental connection between the two fiber populations. In 8-week-old muscles the proportions of slow MHC-positive extrafusal fibers that ringed muscle spindles ranged from 0-100%. In contrast, proportions of slow MHC-positive intrafusal fibers in spindles ranged from 0-57%. Similar proportions in fiber type composition between intrafusal fibers and surrounding extrafusal fibers were apparent at embryonic days 15 and 16, demonstrating early divergence of extrafusal and intrafusal fibers. Muscle spindles were rarely located within single fascicles. Instead, they were commonly placed where several fascicles converged. The frequent extrafascicular location of spindles suggests migration of intrafusal myoblasts from developing clusters of extrafusal fibers toward the interstitium, perhaps along a neurotrophic gradient established by sensory axons that are advancing in the connective tissue matrix that separates adjoining fascicles.

Animals↗

PubMed1999

[Preoperative staging of colorectal carcinoma].

Carcinoma of the colorectum is one of the most frequent neoplasias, with an incidence of 40 in 100,000. For the effective use of new, differentiated, less invasive treatment options, exact preoperative staging of the tumor is essential. The introduction of endosonography in rectal tumor staging allows for exact differentiation of the rectal wall layers and thus of tumor stages 1-3 with median accuracy of 89%. Magnetic resonance imaging of the rectum, especially in double-contrast technique, can also be employed in high and stenosing tumors and leads to an average accuracy of 85% for the stages 1-4. Computed tomography is the method of choice in screening for metastases. In lymph node staging, all modalities show only moderate accuracy around 75%.

Colon↗