Search PubMed⌕ Search

Biomedical subjects

A Wagner

Publications and source records attributed to A Wagner.

At least 289 records · Page 16Linked to original sources
PubMed1995

Virtual image guided navigation in tumor surgery--technical innovation.

We present a new visualization system for image-guided stereotactic navigation in tumor surgery. The combination of frameless stereotactic localization technology with real-time video processing permits the visualization of medical imaging data as a video overlay during the actual surgical procedure. Virtual computer-generated anatomical structures are displayed intraoperatively in a semi-immersive head-up display. This results in surgical navigation assistance without limiting the judgement of the physician based on the continuous observation of the operating field. The case presented documents the potential of augmented reality visualization concepts in tumor surgery of the head.

Computer Simulation↗
PubMed1995

In vivo administration of granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor increases neutrophil oxidative burst activity.

The influence of CSF therapy on the superoxide (O2-) releasing capacity in response to N-formyl-methionyl-leucyl-phenylalanine (FMLP) of neutrophils from 32 patients with testicular cancer receiving high-dose chemotherapy followed by autologous bone marrow transplantation (ABMT) was assessed: 8 patients were treated as control group without CSF therapy, 12 patients received GM-CSF, and 12 patients received G-CSF. To monitor the kinetics of the respiratory burst, leukocytes were collected before initiation of chemotherapy and ABMT, during CSF administration on days 1 and 3 after leukocyte recovery, and 7 days after leukocyte recovery (controls) or 3 days after the end of CSF therapy. Neutrophils from patients who received GM-CSF showed a significantly higher superoxide anion release compared with control patients (p < 0.001). O2- production in these patients was higher than that achieved by in vitro preincubation of neutrophils from control patients. Increased burst activity was seen only during infusion of GM-CSF and returned to pretherapeutic values after the end of GM-CSF administration. A similar but less pronounced increase was seen in patients who received G-CSF. In vitro preincubation of neutrophils from the same patients with GM-CSF, G-CSF, or TNF showed that O2- production by neutrophils from patients receiving GM-CSF could not be further enhanced, whereas O2- production by neutrophils derived from patients receiving G-CSF could be further augmented by TNF but not by GM-CSF. Interestingly, neutrophils from patients treated with GM-CSF but not those with G-CSF therapy retained a higher response to in vitro stimulation with GM-CSF or TNF after the end of CSF administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Marrow Transplantation↗
PubMed1995

Lethal Waterhouse-Friderichsen syndrome in posttraumatic asplenia.

We herein report a case of fulminant lethal Waterhouse-Friderichsen syndrome in an elderly female patient seven years after posttraumatic splenectomy. In contrast to various reports, this patient had not been vaccinated against Streptococcus pneumoniae, Neisseria meningitidis, or Haemophilus influenzae, respectively, although infections with these microorganisms are known to cause the main lethal diseases in asplenic patients. Again, we recommend obligatory vaccinations against the mentioned bacteria for it is known that this decreases the risk of fatal septic events in these patients. To optimize prevention, it is imperative to vaccinate patients undergoing splenectomy before discharge from hospital.

Blood Coagulation Tests↗
PubMed1995

Oxygen radical generation and acute pancreatitis: effects of dibutyltin dichloride/ethanol and ethanol on rat pancreas.

Recent studies suggest that enhanced release of free oxygen radicals plays an important role in the pathogenesis of acute pancreatitis. Therefore, we studied the activity of the oxygen radical generating xanthine oxidase (XOD) in pancreatic tissue from rats treated with either dibutyltin dichloride/ethanol (DBTC/EtOH: 6 mg kg-1/13.7 mg kg-1, i.v.), ethanol alone (EtOH: 13.7 mmol kg-1, i.v.), or isotonic saline (NaCl) as control. We also investigated activities of the oxygen radical scavengers superoxide dismutase (SOD) and glutathione peroxidase (GPX). In addition, levels of the lipid peroxidation marker malondialdehyde (MDA) were determined. Enhanced activity of XOD was not detected. While SOD activity 1 and 6 h after treatment was significantly more reduced by DBTC/EtOH than by EtOH alone, no difference was found thereafter. Correspondingly, both regimens diminished GPX activity. Moreover, DBTC/EtOH and EtOH rapidly increased MDA levels within 1 h, indicating release of oxygen radicals early on after administration. After 16 h the MDA concentration was still elevated only in the DBTC/EtOH group. Although similar metabolic alterations were observed in both groups, only DBTC/EtOH induced acute interstitial pancreatitis within 24 h. We conclude that (a) a tissue imbalance between oxidants and antioxidants might be of importance in the pathogenesis of DBTC/EtOH-induced acute interstitial pancreatitis; (b) although EtOH increases oxygen radical levels, additional damage is required for development of acute pancreatitis; (c) XOD does not seem to be responsible for significant oxygen radical generation; and (d) the DBTC/EtOH model is a useful tool to study acute interstitial pancreatitis in rats.

Acute Disease↗
PubMed1995

alpha-Interferon therapy for congenital dyserythropoiesis type I.

We report the case of a 28-year-old female followed for congenital dyserythropoiesis type I which required repeated transfusions. Alpha-2a interferon treatment was started because of post-transfusion chronic viral hepatitis type C. Following this treatment, haemoglobin level increased and reached normal value during the 24 weeks of interferon treatment. When interferon therapy was stopped, haemoglobin level returned to previous values, requiring more transfusions. Resumption of interferon therapy resulted again in a complete normalization of haemoglobin level. Erythrokinetic studies demonstrated a striking reduction of the ineffective erythropoiesis, and electron microscopy study a reduction in nuclear structure abnormalities. To our knowledge, this is the first report of the efficacy of interferon in congenital dyserythropoiesis.

Adult↗
PubMed1995

Canine distemper virus persistence in the nervous system is associated with noncytolytic selective virus spread.

Canine distemper virus (CDV), a negative-strand RNA morbillivirus, causes a progressive demyelinating disease in which virus persistence plays an essential role. The antiviral immune response leads to virus clearance in the inflammatory lesions. However, CDV can replicate and persist outside these inflammatory lesions within the brain. How CDV is capable of persisting in the presence of an effective antiviral immune response is poorly understood. In the present investigation, we studied several aspects of virus replication in primary dog brain cell cultures (DBCC), comparing an attenuated CDV strain and a virulent CDV strain. Confluent DBCC were infected with either virulent A75/17-CDV or attenuated Onderstepoort-CDV and monitored for 60 days. Persistence was not associated with defective virus production, because all mRNAs and corresponding proteins were continuously expressed in the noncytolytic infection. Quantitative measurements did not detect a difference between the two types of infection in the rate of virus transcription and protein synthesis at the level of the single cell. However, electron microscopy and virus titration experiments showed that in the persistent CDV infection virus budding is strongly limited compared with that of the attenuated virus. Morphometry and immunocytochemistry showed profound differences in the way the two viruses spread in the culture. The attenuated CDV spread randomly to immediately adjacent cells, whereas persistent CDV spread selectively to more-distant cells by way of cell processes. In conclusion, the present study supports a mechanism of CDV persistence through selective spread by way of cell processes, enabling virulent CDV to invade the central nervous system without the need of releasing much virus into the extracellular space.

Animals↗
PubMed1995

Poor ventilatory response to mild hypoxia may inhibit acclimatization at moderate altitude in elderly patients after carotid surgery.

Peripheral chemoreceptors (carotid bodies) are the main sensing organs for hypoxaemia. During carotid surgery, the carotic body in the bifurcation of the common carotid artery is often involved and damaged or destroyed. Animals lose their ability to adapt to high altitude after experimental denervation of the carotid bodies. The objective of our study was to evaluate the ability of human patients to adapt to moderate altitude after single side carotid surgery. Blood gas analysis at rest at 171 m and after car and cable car transport to 1600 m before and after carotid surgery was performed. Mean(s.d.) paO2 decreased insignificantly from 74.8(3.56) at 171 m altitude to 71.6(2.07) at 1600 m (P = n.s.), means(s.d.) paCO2 decreased significantly from 36.2(2.86) to 31.4(2.7) mmHg (P < 0.05) before carotid surgery. Months after surgery, a significant drop in paO2 occurred after identical passive exposure to moderate altitude: mean(s.d.) paCO2 at 171 m 74.4(3.65) mmHg, at 1600 m 65.8(3.70) mmHg (P < 0.01), paCO2 did not change significantly. Mean(s.d.) paCO2 at 171 m: 36.0(2.35), at 1600 m 36.2(2.86) mmHg (P = n.s.). Although the sample investigated was small, after single side carotid surgery patients seem to lose their ability for satisfactory ventilatory response to acute exposure to moderate altitude. This is of possible alpine medical importance.

Acclimatization↗
PubMed1995

Emergency mechanical ventilation at moderate altitude.

Portable emergency ventilators are commonly used in the prehospital setting in the transport of critically ill patients in hypobaric environments. The aim of our trial was to evaluate the influence on minute ventilation and blood gas analysis of moderate altitude (3000 m) compared to 171 m in healthy volunteers during mechanical ventilation with the Draeger Oxylog ventilator. At 3000 m, the delivered minute volume increased by 9.8% in the air mix mode and by 14.6% in the no air mix mode. PaO2 at 3000 m altitude decreased by 33.3% in the air mix mode, and no statistical change was observed in the no air mix mode. PaCO2 at 3000 m altitude decreased by 9.0% in the air mix mode and by 12.8% in the no air mix mode. These changes are of sufficient magnitude and importance to require monitoring of minute volume to prevent barotrauma or volume-related trauma and to monitor oxygenation by pulse oximetry during emergency mechanical ventilation at moderate altitude.

Adult↗
PubMed1995

The small group consensus process for changing physician practices: influenza vaccination.

OBJECTIVE: To evaluate the effectiveness of a small group consensus process in enhancing compliance with guidelines for influenza vaccination among older HMO members. DESIGN: A controlled study of the practice of primary care physicians, with pre/post comparisons and a 2-year follow-up. SETTING: An 84,000 member prepaid staff model HMO group practice. PARTICIPANTS: Primary care clinicians (N = 36) practicing in a staff model HMO. INTERVENTION: A small-group process, including opinion leader, feedback, and group decision making. MAIN OUTCOME MEASURE: Percentage of patients in a given physician-panel who received influenza immunization. RESULTS: Improvement in vaccination rate from 60.8% to 72.35% (with further increases over 2 successive years), in the intervention group as compared with improvement in the control from 60.7% to 65.93%. CONCLUSION: In this model, the small group consensus process resulted in an alteration in physician practice pattern, yielding a significant improvement in immunization rates above the already-established level of 60%.

Aged↗
PubMed1995

Influence of in vivo administration of GM-CSF and G-CSF on monocyte cytotoxicity.

The influence of colony-stimulating factors (CSFs) on the monocyte functions of 32 patients with refractory testicular cancer receiving high-dose chemotherapy followed by autologous bone marrow transplantation (ABMT) was tested. Eight patients were treated as a control group without CSF therapy, 12 patients received recombinant human granulocyte-macrophage-CSF (rhGM-CSF), and 12 patients received recombinant human granulocyte-CSF (rhG-CSF). For the assessment of monocyte activation induced by CSF expression of major histocompatibility complex (MHC) class I and II antigens, production of tumor necrosis factor (TNF) and monocyte-mediated cytotoxicity against tumor cell targets were chosen. Monocytes from patients with GM-CSF therapy showed a significant increase in MHC class I and II antigen expression as compared to patients without CSF treatment (p < 0.001). A significant increase in the expression of MHC class I was seen in monocytes from patients under G-CSF treatment, whereas no change of class II antigens was noticed. Production of TNF and monocyte-mediated cytotoxicity against U937 tumor cells was significantly increased in monocytes derived from patients receiving GM-CSF, as compared to those from the control group, while no effect was detectable in monocytes from patients with G-CSF therapy. However, after in vitro stimulation with interferon-gamma (IFN-gamma), monocytes derived from GM-CSF as well as from G-CSF treated patients responded with a significantly higher TNF-production and cytotoxicity than monocytes from control patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

MR imaging in advanced abdominal pregnancy. A case report of fetal death.

Abdominal pregnancy is a rare but life-threatening condition. The preoperative diagnosis may be difficult. When there is a suspicion of abdominal pregnancy and ultrasonographic findings are equivocal or inconclusive, MR imaging should be performed. We report a case of an abdominal pregnancy of 28 weeks' gestation diagnosed by MR.

Adult↗