[Computed tomography in multiple trauma patients: technical aspects, work flow, and dose reduction]. / Polytrauma-Computertomographie : Technische Grundlagen, Workflow und Dosisreduktion.

CLINICAL/METHODICAL ISSUE: Patients with severe, life-threatening trauma require a fast and accurate clinical and imaging diagnostic workup during the first phase of trauma management. STANDARD RADIOLOGICAL METHODS: Early whole-body computed tomography has clearly been proven to be the current standard of care of these patients. METHODICAL INNOVATIONS: A similar imaging quality can be achieved in the multiple trauma setting compared with routine imaging especially using rapid, latest generation computed tomography (CT) scanners. PERFORMANCE: This article encompasses a detailed view on the use of CT in patients with life-threatening trauma. A special focus is placed on radiological procedures in trauma units and on the methods for CT workup in routine cases and in challenging situations. Another focus discusses the potential of dose reduction of CT scans in multiple trauma as well as the examination of children with severe trauma. ACHIEVEMENTS: Various studies have demonstrated that early whole-body CT positively correlates with low morbidity and mortality and is clearly superior to the use of other imaging modalities. PRACTICAL RECOMMENDATIONS: Optimal trauma unit management means a close cooperation between trauma surgeons, anesthesiologists and radiologists, whereby the radiologist is responsible for a rapid and accurate radiological workup and the rapid communication of imaging findings. However, even in the trauma setting, aspects of patient radiation doses should be kept in mind.

Histologic work-up of non-palpable breast lesions classified as probably benign at initial mammography and/or ultrasound (BI-RADS category 3).

PURPOSE: To determine the accuracy of a probably benign assessment of non-palpable breast lesions (BI-RADS category 3) at mammography and/or ultrasound with immediate histological work-up. MATERIALS AND METHODS: Stereotactic or ultrasound guided core needle breast biopsy (NBB) was performed to evaluate 288 lesions, which were prospectively assessed as BI-RADS category 3. Imaging findings included 195 masses, 73 calcification cases, 16 focal asymmetries, and four architectural distortion cases. After NBB, patients underwent either open surgical biopsy (OSB) (n=204) or mammographic follow-up (n=84) for at least 24 months. Histological results of NBB were compared with those of OSB. RESULTS: Three of the 288 lesions (1.0%) proved to be malignant at histological work-up, two of them were ductal carcinoma in situ (DCIS) and one of them was an invasive carcinoma. NBB revealed invasive carcinoma in 1/288 (0.35%) and atypical ductal hyperplasia (ADH) in 13/288 (4.5%) lesions. OSB revealed DCIS in 2/204 (1%) and invasive carcinoma in 1/204 (0.5%) lesions. The two DCIS were underestimated as ADH by NBB. The remaining 285 (99%) lesions proved to be benign at OSB or remained stable during follow-up. CONCLUSION: Confirmed by tissue diagnosis, the low likelihood of malignancy of prospectively assessed probably benign lesions is below the 2% threshold established for BI-RADS category 3. Imaging follow-up is a safe and effective alternative to immediate histological work-up for such lesions.

Postoperative pain control in total joint arthroplasty: a prospective, randomized study of a fixed-dose, around-the-clock, oral regimen.

This randomized, prospective study assessed postoperative pain control in 119 patients undergoing total joint arthroplasty. Group 1 (59 patients) received scheduled, around-the-clock, oral opioids and group 2 (60 patients) received oral opioids on an as-needed basis. Both groups had parenteral opioids available for breakthrough pain. The average scores for group 1 were lower than group 2. Differences were significant in sensory scores (AM day 1; AM and PM day 2), affective scores (PM day 2), total pain (PM day 2), visual analog scale (PM day 2), and present pain intensity index (AM day 1; PM day 2). Group 1 averaged 2.05 breakthrough pain doses and group 2 averaged 3.47 doses (P=.003), an average savings of 17.2% of the cost of pain medications during the first 2 postoperative days. The results indicate that scheduled, around-the-clock, oral opioids are an effective treatment regimen for postoperative pain control in total joint arthroplasty patients.

Prevention of gastrointestinal iron absorption by chelation from an orally administered premixed deferoxamine/charcoal slurry.

STUDY OBJECTIVE: To investigate the effect of an orally administered premixed slurry of deferoxamine mesylate (DFO) and activated charcoal (AC) on the gastrointestinal (GI) absorption of ferrous sulfate under physiologic conditions. METHODS: This was a prospective, crossover, controlled human volunteer study. Participants were healthy adult subjects aged 25 to 38 years. Volunteers ingested either 5 mg/kg ferrous sulfate alone, 5 mg/kg ferrous sulfate added to 25 g of 20% (weight/ volume) AC, or 5 mg/kg ferrous sulfate added to a premixed slurry consisting of 8 g of DFO and 25 g of 20% (weight/volume) AC. The same group of volunteers was used in each limb of the study. Serum iron concentrations were measured at baseline and at 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, and 24 hours after ingestion for all subjects. Urinary iron was determined over the first 12 hours after ingestion for each limb. The maximum iron concentration (Cmax), the time to maximum iron concentration (Tmax), and the area under the curve (AUC) were compared for all three limbs. RESULTS: The AUC (P = .042) and Cmax (P = .017) were significantly lower in all subjects in the DFO/AC limb compared with the two control limbs. There was no significant difference in the Tmax iron concentration (P = .77). In the ferrous sulfate control limb, female volunteers had a significantly higher mean Cmax (P = .008) and AUC (P = .014) than males. Iron was undetectable in all baseline and 12-hour urine collections. CONCLUSION: In this model, a premixed 1:3 (weight/weight) DFO/ AC slurry reduced the GI absorption of ferrous sulfate in adult volunteers under physiologic conditions.

Oligosaccharide sequences of endothelial cell surface heparan sulfate proteoglycan with affinity for lipoprotein lipase.

Lipoprotein lipase (LpL) catalyzes the hydrolysis of triglycerides in plasma lipoproteins at the luminal surface of the vascular endothelium. This enzyme is bound via electrostatic interactions to heparan sulfate (HS). The specific endothelial cell surface HS oligosaccharide sequences that are necessary for binding of LpL to HS have not been characterized. To identify this LpL-binding oligosaccharide sequence, oligosaccharides were isolated from bovine aortic endothelial cell-derived HS and assessed for LpL binding properties. Endothelial HS chains that were isolated from endothelial total cell-associated proteoglycans were deacetylated by complete hydrazinolysis, cleaved with nitrous acid (pH 4.5), and reduced with [3H]NaBH4. The resulting fragments composed of N-sulfated glucosamine-rich oligosaccharides terminating with [3H]2,5-anhydromannitol (AManR) were chromatographed on a LpL-Sepharose column. A high affinity decasaccharide was isolated and characterized. Disaccharide analysis of this decasaccharide indicated that it yielded only the disaccharide IdceA(2-SO4)-->AManR(6-SO4) on treatment with nitrous acid at low pH. Therefore, the sequence of the LpL-binding decasaccharide is [IdceA(2-SO4) alpha 1-4GlcNSO4(6-S0(4)) alpha 1-4]4-IdceA(2-SO4) alpha 1-4AManR(6-SO4) and is distinct from those that bind antithrombin and basic fibroblast growth factor. Partial depolymerization of endothelial HS chains with hydrazine/high pH nitrous acid treatment gave rise to lipase-binding oligosaccharides larger than decasaccharide. However, further complete depolymerization of these oligosaccharides resulted in only a high affinity decasaccharide composed of repeating disaccharide units of [IdceA(2-SO4) alpha 1-4GlcNSO4(6-S0(4))]. These results indicate that the decasaccharide is the active fragment that binds to LpL with high affinity. Molecular modeling studies of the decasaccharide indicate that it presents a linear array of negatively charged sulfate groups that may adopt a favorable disposition to bind to peptide region(s) comprised of basic amino acid residues of LpL with high affinity.

Development of techniques for the isolation of iron from biological material for measurement of isotope ratios by fast atom bombardment mass spectrometry.

Stable isotopes have gained prominence in nutrition and trace element research. Fast atom bombardment mass spectrometry (FAB-MS) measurement of iron isotope ratios has an accuracy of > or equal to 99.7% with the stable isotopes (54)Fe, (56)Fe, and (58)Fe with relative standard deviations (RSDs) of < or equal to 0.9%. The isolation of iron from biological matrices can be accomplished in 4 h with almost total removal of isobaric interferences caused by (39)KOH, (39)K.H2O, (40)CaOH, and/or (40)Ca.H2O. FAB-MS isotope enrichment measurements from this method compare favorably to predicted absorption/enrichment levels.

Tandem mass spectrometric studies of the fragmentation of penicillins and their metabolites.

The fragmentation of two penicillins, ampicillin and amoxicillin, and their principal metabolites has been studied by a combination of liquid chromatography/thermospray mass spectrometry and tandem mass spectrometry. A high-resolution tandem mass spectrometer was used to obtain chemical ionization, fast-atom bombardment, and collision-induced dissociation mass spectra. Structural information and fragmentation mechanisms have been deduced from ions in the mass and collision spectra. This knowledge is useful in the analysis and identification of metabolites of ampicillin and related drugs in human body fluids.

3-Phenylpropenes as mechanism-based inhibitors of dopamine beta-hydroxylase: evidence for a radical mechanism.

A series of ring-substituted 3-phenylpropenes has been examined as mechanism-based inhibitors for the copper protein dopamine beta-hydroxylase. p-HO-, p-CH3O-, m-HO-, m-CH3O-, p-Br-, and p-CN-substituted phenylpropenes all inactivate the enzyme under turnover conditions, requiring ascorbate and oxygen. Replacement of the benzylic hydrogens in 3-(p-hydroxyphenyl)propene with deuterium results in a kinetic isotope effect of 2.0 on kinact/KO2 but in no effect on the partition ratio, Vmax/kinact, consistent with a stepwise mechanism for hydrogen abstraction and oxygen insertion. The partition ratio is unchanged in the pH range from 4.5 to 7.1. Determination of the kinetics of inactivation and the partition ratios for each of these ring-substituted phenylpropenes has allowed determination of the respective V/KO2 values. A linear free energy plot of these values as a function of sigma+ gives a rho value of -1.2, while the partition ratios show only a slight decrease upon going electron-withdrawing groups. The results are consistent with a mechanism for dopamine beta-hydroxylase in which a hydrogen atom is abstracted to form a benzylic radical, which then partitions between hydroxylation and enzyme inactivation.

Abiotic synthesis of purines and other heterocyclic compounds by the action of electrical discharges.

The synthesis of purines and pyrimidines using Oparin-Urey-type primitive Earth atmospheres has been demonstrated by reacting methane, ethane, and ammonia in electrical discharges. Adenine, guanine, 4-aminoimidazole-5-carboxamide (AICA), and isocytosine have been identified by UV spectrometry and paper chromatography as the products of the reaction. The total yields of the identified heterocyclic compounds are 0.0023%. It is concluded that adenine synthesis occurs at a much lower concentration of hydrogen cyanide than has been shown by earlier studies. Pathways for the synthesis of purines from hydrogen cyanide are discussed, and a comparison of the heterocyclic compounds that have been identified in meteorites and in prebiotic reactions is presented.

On the abiotic formation of amino acids. I. HCN as a precursor of amino acids detected in extracts of lunar samples. II. Formation of HCN and amino acids from simulated mixtures of gases released from lunar samples.

Two studies on the abiotic formation of amino acids are presented. The first study demonstrates the role of hydrogen cyanide as a precursor of amino acids detected in extracts of lunar samples. The formation of several amino acids, including glycine, alanine, aspartic acid, and glutamic acid, under conditions similar to those used for the analysis of lunar samples is demonstrated. The second study investigates the formation of hydrogen cyanide as well as amino acids from lunar-sample gas mixtures under electrical discharge conditions. These results extend the possibility of synthesis of amino acids to planetary bodies with primordial atmospheres less reducing than a mixture of methane, ammonia, hydrogen and water.

Search for organic and volatile inorganic compounds in two surface samples from the chryse planitia region of Mars.

Two surface samples collected from the Chryse Planitia region of Mars were heated to temperatures up to 500 degrees C, and the volatiles that they evolved were analyzed with a gas chromatograph-mass spectrometer. Only water and carbon dioxide were detected. This implies that organic compounds have not accumulated to the extent that individual components could be detected at levels of a few parts in 10(9) by weight in our samples. Proposed mechanisms for the accumulation and destruction of organic compounds are discussed in the light of this limit.

Organic analysis of lunar samples and the Martian surface.

In addition to the organogenic elements (H, C, N, O, S, P) which are necessary for the synthesis of organic molecules, the lunar samples from Apollo 11, 12, 14 and 15 contain substantial amounts (approximately equal to 10 to 100 microgram/g) of CO, N2 and CO2, which are released at relatively high temperatures and smaller amounts (approximately equal to 0.1 to 10 microgram/g) of more complex organic compounds (e.g. benzene). Most of these analyses have been performed by mass spectrometry or by combined gas chromatography-mass spectrometry after appropriate volatilization. The release of very small amounts of water has also been observed and is consistent with the findings of goethite (FeO.OH) and with measurements by the suprathermal ion detector. The lunar surface provides one of the less favorable solar system models for the synthesis of organic compounds yet small amounts of these compounds have been detected in the returned samples. It is reasonable to assume that the different physical and developmental features of the planet Mars (increased gravitational field, presence of an atmosphere with CO2, CO and H2O, recent volcanic and tectonic activity, etc.) would favor an increased organic content of the surface of this planet relative to the moon. Therefore the organic molecules present in the Martian soil should be measurable by miniaturized mass spectrometers after fractional distillation or gas chromatographic separation of the volatiles released by moderate heating.