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Biomedical subjects

P Reimer

Publications and source records attributed to P Reimer.

At least 127 records · Page 7Linked to original sources
PubMed1990

Receptor imaging: application to MR imaging of liver cancer.

A new contrast agent for magnetic resonance (MR) imaging, directed to asialoglycoprotein (ASG) receptors on hepatocytes, was used for detection of liver cancer in rats. Ultrasmall superparamagnetic (mean size, 12 nm) particles of iron oxide (USPIOs) were targeted to ASG receptors by coating particles with arabinogalactan (AG). Liver T2 relaxation times decreased more effectively after a single intravenous administration of AG-USPIO than after an equal dose of a conventional superparamagnetic liver MR contrast agent (AMI-25; mean size, 72 nm). Receptor affinity studies demonstrated that receptor-mediated attachment and subsequent cellular endocytosis do not occur in primary malignant (hepatocellular carcinoma) or metastatic (adenocarcinoma) tumors, because the surface ASG receptors are lost during malignant dedifferentiation. In vitro relaxation and in vivo MR imaging experiments of liver tumors show that targeting USPIO to hepatocytes rather than to the mononuclear phagocytic system allows a considerable dose reduction, increases tumor-liver contrast, and potentially allows distinction of ASG-positive (benign hepatocellular) and ASG-negative (malignant hepatocellular) tumors.

Animals↗
PubMed1990

MR receptor imaging: ultrasmall iron oxide particles targeted to asialoglycoprotein receptors.

Previously we have reported that ultrasmall superparamagnetic iron oxide (USPIO) particles migrate across capillary endothelium, a prerequisite for the design of particulate pharmaceuticals for MR receptor imaging. In the current study, USPIO particles are directed specifically to asialoglycoprotein (ASG) receptors by coupling galactose terminals in the form of arabinogalactan (AG) to these particles. Biodistribution data showed that ASG-directed, AG-coated USPIO (AG-USPIO) particles selectively accumulate in the liver but not in other organs. Electron microscopy of liver showed electron-dense iron oxide particles bound to hepatocyte cell-surface membranes and in large numbers within intracellular lysosomes. The specificity of AG-USPIO for asialoglycoprotein receptors was confirmed by incubation experiments with and without ASG-blocking agents such as D(+)galactose and asialofetuin. In vivo MR imaging in rats showed a significant decrease in liver signal intensity at low doses (2 mumol Fe/kg); no significant changes were observed in the spleen. This decrease in signal intensity is larger than that observed with conventional iron oxides at equal doses. These initial data suggest that, for the first time, superparamagnetic agents can be directed to specific sites for MR imaging by strategies such as receptor targeting.

Animals↗
PubMed1990

[Diagnosis of carotid body tumor by imaging procedures].

The imaging techniques available for the diagnosis of tumors of the glomus caroticum are discussed with reference to four cases (three patients, one with tumor bilaterally). Taking into consideration the practicability and invasiveness of the investigations as well as the risks and costs involved, we propose that the procedures be performed in the following sequence: ultrasonography, Doppler ultrasonography, computed tomography (CT) or (even better) magnetic resonance imaging (MRI), and selective angiography. In most cases where there is a non-inflammatory mass in the neck, ultrasonography and Doppler ultrasonography may be adequate to establish the diagnosis of a glomus caroticum tumor. B-scan ultrasonography reveals an inhomogeneous mass that pushes the carotid arteries apart and an arteriovenous shunt may be seen using the Doppler technique. CT and MRI show the full extent of the tumor and provide information about infiltration of adjacent structures. Selective intra-arterial angiography confirms the diagnosis, demonstrating a profound vascularized tumor in the carotid bifurcation. If angiography leads to identification of an afferent vessel, selective embolization of the tumor may be performed, thus enabling a much safer operation with less blood loss.

Adult↗
PubMed1989

Concentrations of lead in aquatic macrophytes from Shoal Lake, Manitoba, Canada.

The ability of aquatic macrophytes to accumulate lead was examined in the context of sample site, sample date, depth, organ and species. Considerable variations in lead concentrations were found between the 11 species of macrophytes studied. The mean lead concentration for all species sampled was 16 microg/g (dry weight) ranging from 0-78 microg/g. Analysis of variance indicated that there were significant differences in the mean lead content of macrophytes collected from different sample sites. Similarly, significantly higher values were observed for plants collected from the upper 2m of water. Seasonal trends in lead accumulation were not observed for Shoal Lake macrophytes.

Journal Article↗
PubMed1989

[Percutaneous drainage of abscesses after stomach surgery].

Fifteen abscesses following various types of gastric surgery in 14 patients were treated by three different methods: 1. Multiple puncture under sonographic control, with complete drainage of the abscess. 2. The introduction of a catheter. 3. In the presence of a fistula, introduction of a catheter into the abscess through the fistula. Amongst the 14 patients, one had to undergo further surgery because of intestinal bleeding. In the other patients, there was complete healing without any complications or further surgery.

Abscess↗
PubMed1989

[The relevance of sonographic diagnosis of cervical lymph nodes in tumors of the head and neck].

Thirty patients with a squamous cell carcinoma of the head and neck, with cervical lymph nodes which could be shown by ultrasound but not by palpation of the neck, are reviewed. The cervical lymphatic nodes, which were similar in size to the preoperative ultrasonic measurement, were removed by elective neck dissection. Histological examination showed a reactive inflammation only, without tumour infiltration, in 83.3% of the cases. These clinically inconspicious lymph nodes, which were homogeneous on ultrasound scan and could be easily differentiated from the background, obviously show the premalignant stage of tumour spread. The consequences for the operation and later follow-up are discussed.

Biopsy↗
PubMed1989

[Ultrasound sonography in the diagnosis and follow-up of Achilles tendon rupture].

In addition to allowing definite diagnosis of Achilles tendon rupture and localization of the rupture site, ultrasonography also enables the examiner to grade the rupture and the course of healing for quantity and quality. Twenty patients with subcutaneous achilles tendon rupture were examined in a prospective study that is still in progress. In this trial an operative and a conservative-functional treatment with a newly developed shoe were compared. The dynamic examination revealed adaptation of the tendon in plantar flexion in two-thirds of the patients. After 2 weeks continuity of the tendon was restored in all patients. A remarkable increase in the regeneration of the tendon at the rupture or suture site was observed from the 4th to the 12th week. The variations in tendon structure were assessed, and a classification is presented.

Achilles Tendon↗
PubMed1989

[Sonographic diagnosis and differential diagnosis of neck cysts].

We report 101 patients with the clinical diagnosis of a branchial cyst investigated by ultrasonography. In 78 cases the diagnosis of a branchial cyst was confirmed by the ultrasound findings. The picture of a typical cyst was found in 26 cases, whereas a complex cyst filled with sludge or debris was found in 52 patients. Histology revealed a different diagnosis in 7 cases of ultrasonic complex cysts. Of 23 patients where a branchial cyst was excluded by ultrasound, histology showed a lesion other than a branchial cyst in 19 cases. In total, only 34.6% of the histologically confirmed branchial cysts displayed the typical signs of such a cyst on ultrasonography. However, in 91% of the patients with an actual branchial cyst we were able to confirm the diagnosis by ultrasound before operation. The differential diagnosis of other benign and malignant lesions of the neck resembling branchial cysts is discussed with examples.

Branchioma↗
PubMed1989

[Management of sonography in blunt abdominal trauma].

A standardized management of sonography in blunt abdominal trauma has replaced peritoneal lavage in our department. The sonographic evaluation is performed simultaneously with additional diagnostic and therapeutic procedures in the emergency room. The primary goal is the exclusion of intraabdominal bleeding. The management and the results of the diagnostic procedure are presented with reference to a consecutive series of 314 patients with blunt abdominal trauma or polytrauma. In 71 patients, laparotomy was performed because the sonographic findings were felt to indicate it. Only in two cases was the sonographic assessment incorrect (false-positive). Frequent sonographic and clinical controls are required especially when sonography cannot totally exclude intraabdominal bleeding during the initial assessment. If any discrepancies between negative or uncertain sonographic and suspect clinical findings remain, further high-tech diagnostic methods or exploratory laparotomy become necessary.

Abdominal Injuries↗
PubMed1988

[Ultrasonic morphology of the normal Achilles tendon and pattern of pathological changes].

The anatomical structure of the Achilles tendon causes a fibrillary echo texture with fine, parallel echogenic lines. The peritendineum outlining the tendon can be delineated. Achilles tendon ruptures can easily be detected by ultrasound, as can the structural changes in achillodynia. The typical sonographic patterns of rupture of the Achilles tendon and achillodynia are demonstrated.

Achilles Tendon↗
PubMed1983

[Value of the routine documentation of wound infection and complication rates following general surgical interventions].

1430 patients who underwent general surgery were analysed in a prospective study. The examinations were aimed at showing how the results obtained were influenced by prophylactic antibiotic treatment, bowel preparation and suturing technique. Additionally, it was investigated whether the ordered steps were performed in an adequate manner. Finally the regular documentation of wound infection and complication rate could be found to contribute to improving the operative results by detecting avoidable complications.

Anti-Bacterial Agents↗
PubMedDate not supplied

Dynamic signal intensity changes in liver with superparamagnetic MR contrast agents.

The dynamic effects of three different superparamagnetic magnetic resonance (MR) contrast agents on liver signal were evaluated with an echo-planar imaging technique. The contrast agents were (a) USPIO (ultrasmall superparamagnetic iron oxide), which has a long blood half-life and was developed for MR imaging of lymph nodes and bone marrow; (b) AG (arabinogalactan)-USPIO, an asialoglycoprotein receptor--directed iron oxide with hepatocyte uptake; and (c) AMI-25, a conventional reticuloendothelial iron oxide agent. Dynamic liver signal intensity (SI) curves reflect different uptake mechanisms for the different agents. Receptor blocking experiments indicate that intracellular redistribution or clustering of the AG-USPIO (known to occur from electron microscopy studies) does not contribute to the decrease in liver SI. Monitoring liver SI over time with echo-planar imaging may provide a better understanding of the kinetics of the growing number of MR contrast agents and allow optimization of imaging protocols to exploit peak enhancement.

Animals↗