Showing papers by "Chris Boesch published in 2003"

Virtopsy, a new imaging horizon in forensic pathology: virtual autopsy by postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI)--a feasibility study

Abstract: Using postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI), 40 forensic cases were examined and findings were verified by subsequent autopsy Results were classified as follows: (I) cause of death, (II) relevant traumatological and pathological findings, (III) vital reactions, (IV) reconstruction of injuries, (V) visualization In these 40 forensic cases, 47 partly combined causes of death were diagnosed at autopsy, 26 (55%) causes of death were found independently using only radiological image data Radiology was superior to autopsy in revealing certain cases of cranial, skeletal, or tissue trauma Some forensic vital reactions were diagnosed equally well or better using MSCT/MRI Radiological imaging techniques are particularly beneficial for reconstruction and visualization of forensic cases, including the opportunity to use the data for expert witness reports, teaching, quality control, and telemedical consultation These preliminary results, based on the concept of "virtopsy," are promising enough to introduce and evaluate these radiological techniques in forensic medicine

Transcriptional adaptations of lipid metabolism in tibialis anterior muscle of endurance-trained athletes

Abstract: It was hypothesized that transcriptional reprogramming is involved in the structural and functional adaptations of lipid metabolism in human tibialis anterior muscle (TA) from endurance-trained mal...

Mapping fiber orientation in human muscle by proton MR spectroscopic imaging

Abstract: Proton magnetic resonance spectroscopic imaging (1H-MRSI) was used to determine muscle fiber orientations in human calf muscles. The method is based on the fact that some resonances show orientation-dependent dipolar splitting, caused by incomplete motional averaging. This leads to proton spectra that depend strongly on the angle between muscle fibers and the magnetic field B0. The orientation-dependent dipolar splittings were mapped using a fit with a basis set of predefined coupling patterns reflecting the fiber orientation. The fitted coupling patterns were displayed as images and assigned to different muscles based on segmented MR images. They showed gross differences in fiber orientation between some muscles, including m. soleus and m. tibialis anterior, for all subjects. In addition, smaller but significant differences between subjects were detected, which could be due to localization differences or real interindividual differences. Since dipolar splitting affects metabolite intensities, it is important to take this effect into account when calculating metabolite concentrations from MR spectra in muscle tissue. Spatial maps of the MR signals of trimethyl-ammonium groups and creatine/ phosphocreatine revealed significant differences in intensity between muscles. Magn Reson Med 49:424–432, 2003. © 2003 Wiley-Liss, Inc.

Cerebral energy metabolism in phenylketonuria: findings by quantitative In vivo 31P MR spectroscopy.

Abstract: Both severe impairments of brain development in untreated infants and acute reversible neurotoxic effects on brain function are clinical features of phenylketonuria (PKU). For determining whether impairments of cerebral energy metabolism play a role in the pathophysiology of PKU, quantitative in vivo 31P magnetic resonance spectroscopy (MRS) was performed in a supratentorial voxel of 11 adult PKU patients and controls. Peak areas of inorganic phosphate; phosphocreatine; α-, β-, and γ-ATP; NAD; phosphomonoesters; phosphodiesters; and a broad phospholipid signal were converted to millimolar concentrations. Mg2+, pH, ADP, the phosphorylation potential, and the relative velocity of oxidative metabolism V/Vmax were derived. Clinical evaluation included mutation analysis, neurologic investigation, intelligence testing, magnetic resonance imaging, and concurrent plasma and brain phenylalanine (Phe), the last by 1H-MRS. Phe loading was performed in five patients with an oral dose of 100 mg/kg body wt L-Phe monitored by spectral EEG analysis. Under steady-state conditions, 31P-MRS revealed normal values for ATP, phosphocreatine, NAD, phosphomonoesters, phosphodiesters, Mg2+, and pH in PKU. ADP (+11%) and the phosphorylation potential (+22%) were increased. Peak areas of inorganic phosphate (−22%) and phospholipid (−8%) were decreased. ADP correlated with concurrent plasma (r = 0.65) and brain (r = 0.55) Phe. During the Phe load, blood Phe levels increased steeply. EEG revealed slowing of background activity. The phosphorylation potential decreased, whereas ADP and V/Vmax increased. In vivo 31P-MRS demonstrated subtle abnormalities of cerebral energy metabolism in PKU in steady-state conditions that were accentuated by a Phe load, indicating a link between Phe neurotoxicity and imbalances of cerebral energy metabolism.

Phenylalanine can be detected in brain tissue of healthy subjects by 1H magnetic resonance spectroscopy.

Abstract: Summary: Transport of phenylalanine (Phe) and the other large neutral amino acids across the blood–brain barrier plays a crucial role in the pathogenesis of phenylketonuria (PKU). Thus, investigation of Phe transport kinetics by means of proton magnetic resonance spectroscopy (1H MRS) became an important research area in the mid 1990s. As 1H MRS measurements of brain phenylalanine are restricted to tissue concentrations above 100–150 µmol/kg wet weight, this approach was possible only in PKU patients, and comparison with healthy controls was not achieved. Using standardized single-dose oral Phe loading in three healthy subjects, it was shown that Phe values increase steeply, peak at about 1 h post load, and decrease thereafter. In a single case study, repetitive Phe loading was then performed to achieve a plateau of high blood Phe concentrations for several hours. It was demonstrated that detection and monitoring of brain Phe concentrations is feasible by means of 1H MRS. This approach constitutes a prerequisite for describing carrier kinetics in health.

Normal hepatic glycogen storage after fasting and feeding in children and adolescents with type 1 diabetes.

Abstract: Objective: Hypoglycemia is the most important acute complication in patients with type 1 diabetes. Liver glycogen is an important storage form of glucose and thus important for maintaining glucose homeostasis. To test the hypothesis whether abnormal storage of glycogen in the liver is contributing to the risk of hypoglycemia in type 1 diabetic children and adolescents, liver glycogen was measured. Study design: Hepatic glycogen concentrations were measured in 19 type 1 diabetic children and adolescents as well as in 19 age-matched controls, following overnight fasting and 4 h after two standardized meals. Hepatic glycogen was assessed by natural abundance 13C nuclear magnetic resonance spectroscopy (MRS). Results: Mean (± SEM) fasting hepatic glycogen concentrations measured in arbitrary units (au) were similar in type 1 diabetic subjects and controls (4.98 ± 0.36 vs. 4.48 ± 0.33 au; p = 0.31). Both groups presented with an increase in liver glycogen concentrations 4 h after the standardized meals (diabetic subjects 5.70 ± 0.37 au, p = 0.01; controls 5.78 ± 0.47 au, p < 0.01). Hepatic glycogen accumulation after feeding was 19.1% in diabetic children and adolescents compared with 35.8% in controls, but this difference did not reach significance. Conclusion: In children and adolescents with moderately controlled type 1 diabetes, hepatic glycogen stores after fasting and feeding are comparable to those of matched controls.