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Biomedical subjects

B G Müller

Publications and source records attributed to B G Müller.

4 recordsLinked to original sources

Plasmid DNA encapsulation and release from solvent diffusion nanospheres.

The first step toward hydrophobic polymer-based nanospheres for gene delivery is to encapsulate and release plasmid DNA. However, encapsulating large hydrophilic molecules in very small nanospheres has been difficult, and only a few examples exist in the literature. For example, maximizing protein and peptide as well as small molecule encapsulation requires adjustments in pH or addition of excipients to charge neutralize, and make less hydrophilic, the compound to be encapsulated. Following this model, we have used a cationic lipid to load and release plasmid DNA from nanospheres made by the phase inversion/solvent diffusion method.

DNA↗

Diagnostic value of MR imaging in comparison to CT in the detection and differential diagnosis of renal masses: ROC analysis.

The aim of this work was to compare MR imaging and CT in the detection of renal masses and in the differential diagnosis between benign and malignant lesions. In 33 patients with 54 renal lesions CT and MR images were evaluated by four readers with regard to tumor detection and characterization using a receiver-operating-characteristics (ROC) analysis. The MRI protocol consisted of a T1-weighted spin-echo (SE) sequence (TR/TE: 300/10 ms) before and after contrast administration and a heavily T2-weighted turbo-SE (TSE) sequence (TR/TE: 5500/150 ms). Az values for the area under the ROC curves for lesion detection were 0.92 +/- 0.04 for CT and 0.91 +/- 0.05 for MRI, respectively, which was not statistically different. The MRI technique was slightly, but not significantly, better than CT in the overall characterization (accuracy in differentiation between benign and malignant) of renal lesions with an Az value of 0.90 +/- 0.05 compared with 0.88 +/- 0.06 for CT. The MRI technique proved to be statistically superior to CT (p < 0.01) in the correct characterization of benign renal lesions. MRI equals CT in the overall detection and differential diagnosis of renal masses. MRI is very helpful for further differential diagnosis of lesions which are equivocal on CT especially in the differentiation between complicated cysts and cystic or hypovascular renal cell carcinoma.

Adult↗

Albumin nanospheres as carriers for passive drug targeting: an optimized manufacturing technique.

PURPOSE: The purpose of this study was to develop a new method to produce albumin particles in the sub-200-nanometer range with a narrow size distribution and in a controlled and reproducible manner. METHODS: A new emulsion crosslinking method was developed using ultrasound and static mixing as homogenization steps and a central composite design was used to evaluate the influence of different process parameters on particle size, polydispersity and yield. RESULTS: Response surface analysis allowed the location of the most important factors. Of all the factors investigated, only the albumin concentration and the aqueous phase volume showed a significant influence on response parameters. Albumin nanospheres with sizes below 200 nm in diameter and very narrow size distributions were obtained in high yields ( > 80%). CONCLUSIONS: This study describes a new preparation method for albumin nanoparticles which are suitable for future drug targeting studies.

Cross-Linking Reagents↗

[Diagnostic evaluation of acute scrotum--testicular perfusion scintigraphy].

The method of and the results obtained with testicular scintigraphy in the differential diagnosis of acute scrotal pain are described. Both sensitivity and specificity were found to be high and in excess of 90%. Misinterpretation of findings is rare and is seldom reported except in case reports. Normal findings usually genuinely reflect absence of disease, and only in the case of suboptimal imaging conditions they might correspond to a false-negative finding in the presence of acute torsion. Chronic torsion may be missed on scintigraphy because of intermediate normalization of arterial perfusion at the time of the investigation. Missed torsion presents a characteristic activity pattern. The halo sign is a proven sign of avitality of the testicle. Orchitis and epididymitis are correlated with hyperperfusion and hyperaemia and are reliably diagnosed by scanning. When testicular scintigraphy is needed immediate availability is essential. In a nuclear medicine department with standard equipment, the investigation can be started within 5 min; it takes about 15 min to perform and the findings can be evaluated within another 5 min. Acute testicular torsion that has already been reliably diagnosed by clinical examination is not an indication for testicular perfusion scintigraphy. This diagnostic procedure is, however, valuable if the clinical findings are equivocal and, especially, if a conservative treatment is planned.

Acute Disease↗