[Ultrasound versus MRI in preventive examinations - a retrospective analysis of 833 patients]

PURPOSE

The benefit of ultrasound in comparison with full-body MRI during a medical checkup in preventive health care was examined with regard to the detection of cardiovascular risk factors, metabolic syndrome, malignant tumors and further relevant findings.

MATERIALS AND METHODS

833 consecutive patients (266 f/567 m, age: 19 - 93 y, mean age: 56.6 y) underwent both ultrasound (extracranial carotid arteries, thyroid, abdominal ultrasound and echocardiography) and whole-body MRI (whole-body MR angiography, head, thorax, abdomen and virtual colonoscopy). For ultrasound examinations, DEGUM level III devices were used (Siemens Acuson Antares, Siemens G60, Siemens, Erlangen). MRI examinations were performed using a 1.5 Tesla MRI device (Siemens Avanto, Siemens, Erlangen). All patients were reviewed retrospectively based on the written reports.

RESULTS

Ultrasound was much more sensitive in detecting early atherosclerotic changes than MRI angiography. In 33 % of the patients, manifestations of atherosclerosis were found. Thoracic (3) and abdominal aortic and mesenteric artery aneurysms (3) were diagnosed by both methods. Hepatic steatosis as an important risk factor of metabolic syndrome was only found by ultrasound in 20.4 % of our patients. Malignant tumors were rare in this population (1.4 %): all abdominal tumors except one renal oncocytoma were found using both methods. MRI and ultrasound were equally sensitive with respect to the detection of small liver foci. As expected, MRI was less sensitive than ultrasound in the diagnosis of thyroid nodes. For intracranial diagnoses, malignant intrathoracic findings and colonic polyps, ultrasound is not the method of choice.

CONCLUSION

For the detection of lifestyle-dependent diseases such as atherosclerosis and metabolic syndrome, ultrasound examination was more sensitive than MRI, and the same was true for the early detection of thyroid diseases. For the detection of malignant abdominal tumors, both methods were equally sensitive. Whole-body MRI can additionally detect pathological changes in the head, lungs and colon.

[Chronic thromboembolic pulmonary hypertension: recommendations of the Cologne Consensus Conference 2010]

In the 2009 European Guidelines on pulmonary hypertension one section covers aspects of pathophysiology, diagnosis and treatment of chronic thromboembolic pulmonary hypertension (CTEPH). The practical implementation of the guidelines for this disease is of crucial importance, because CTEPH is a form of pulmonary hypertension which can be surgically cured. It is, however, frequently diagnosed late in the course of disease and often treated not correctly. In the European Guidelines CTEPH is addressed relatively briefly, although it is a common form of PH which is often overlooked. Any patient with unexplained PH should be evaluated for the presence of CTEPH. A ventilation/perfusion lung scan is recommended as the first step to exclude CTEPH. If the ventilation/perfusion lung scan or multislice CT angiography reveals perfusions defects suggesting the diagnosis of CTEPH, the patient should be referred to a centre with expertise in the medical and surgical management of these patients. After diagnosis of CTEPH the case has to be reviewed by an experienced surgeon in a PEA centre for assessment of operability. The recommendations of the European guidelines are summarized in the current manuscript with additional comments regarding diagnosis and treatment according to most recent evidence.

Limettin and furocoumarins in beverages containing citrus juices or extracts

Phototoxic and photo-genotoxic furocoumarins occur, e.g., in citrus species, parsnip, parsley, celery, and figs. They exhibit phototoxic and photo-genotoxic properties in combination with UV radiation, while less is known about the phototoxicity of the coumarin derivative limettin mainly found in limes and lemons. Risk assessment of dietary furocoumarins is based on a threshold approach and on estimates of 1.2-1.45 mg for the average daily exposure for adults via the diet in several countries. In these estimates, the major contribution to overall daily exposure has been attributed to citrus-flavored non-alcoholic beverages, in spite of a lack of analytical data for those products. Therefore, we analyzed a number of furocoumarins in a variety of citrus-containing beverages and included limettin in the pattern of analyzed constituents. Our findings provide strong evidence that grapefruit juice and not citrus-flavored non-alcoholic beverages is the major source of furocoumarin exposure in a Western diet. Based on these findings it can be assumed that the average dietary exposure to furocoumarins is about 3-fold lower than previously estimated, i.e. in the range of 548 and 2237 microg/day for the average and high consumer, respectively. The coumarin derivative limettin was mainly found in lime products.

Very high prevalence of thyroid nodules detected by high frequency (13 MHz) ultrasound examination

BACKGROUND

The prevalence of thyroid nodules in a healthy population is high: in the German Papillon study, nationwide ultrasound screening of more than 90 000 people using 7.5 MHz scanners revealed the presence of thyroid nodules in 33% of the normal population. A study employing more sensitive 13 MHz scanners has not been conducted so far.

MATERIALS AND METHODS

Six hundred and thirty-five consecutive patients (33% female, 67% male, mean 56.7 years) presenting for a preventive health check up underwent ultrasound screening of the thyroid gland (Siemens Acuson Antares, 13 MHz-linear scanner, B-mode and Power mode) and measurement of the basal TSH (thyroid stimulating hormone) value. Size and degree of vascularization of the thyroid gland and of nodules were determined and analysed retrospectively.

RESULTS

In 432 of 635 patients, thyroid nodules could be detected with an increasing incidence with age, in 338 without goiter. Mean thyroid size was 12.3 mL for women and 20.5 mL for men correlating strongly with body weight. Fifty-three percentage of the nodules were smaller than 5 mm. Incidence of thyroid dysfunction was only 4%. No cancerous lesions could be found.

CONCLUSIONS

Using the 13 MHz technology, we found a substantially higher prevalence of thyroid nodules (68%) than the Papillon study (33%). Even if our population is older than in Papillon, the difference remains in comparable age groups. This is due to the higher sensitivity of 13 MHz scanning. Our study underlines the clinical significance of iodine deficiency and should renew the discussion on routine iodine supplementation.

An unusual cause of acute lower gastrointestinal bleeding

A 45 year old male patient was referred to hospital after syncope during defaecation. Rapid peranal blood loss occurred shortly after admission. Gastroscopy and coloscopy performed as first line diagnostic measures failed to detect the source of haemorrhage. Ultrasound (US) revealed a hypoechoic and hypervascularized tumor mass in the right lower abdomen. A gastrointestinal stromal tumor (GIST) of the jejunum was diagnosed after laparatomy. Collectively US should be among the first line diagnostic procedures in younger patients presenting with lower gastrointestinal haemorrhage.

Aufgaben und Funktionen der ?Senatskommission zur Beurteilung der gesundheitlichen Unbedenklichkeit von Lebensmitteln? der Deutschen Forschungsgemeinschaft

The Senate Commission on Food Safety (SKLM) of the German Research Foundation (DFG) advises authorities and the government on food safety. The risk assessment of foodstuffs, including novel and functional foods, covers the evaluation of food ingredients and additives as well as the evaluation of novel processing methods. In carrying out this task the Commission expresses its opinion primarily on those aspects which are concerned with the safety assessment. In addition, questions relating to the technological need and to nutritional or physiological benefits are also considered. The topics considered may originate from enquiries of the Ministry for Consumer Protection, Nutrition and Agriculture (BMVEL). Other topics may be selected by the Commission on its own initiative, if they are considered to be of particular importance for consumer protection. Within the context of this activity the SKLM also organises symposia and expert discussions, their outcome subsequently being published as resolutions, conclusions or opinions.

Dual function for U2AF(35) in AG-dependent pre-mRNA splicing

The splicing factor U2AF is required for the recruitment of U2 small nuclear RNP to pre-mRNAs in higher eukaryotes. The 65-kDa subunit of U2AF (U2AF(65)) binds to the polypyrimidine (Py) tract preceding the 3' splice site, while the 35-kDa subunit (U2AF(35)) contacts the conserved AG dinucleotide at the 3' end of the intron. It has been shown that the interaction between U2AF(35) and the 3' splice site AG can stabilize U2AF(65) binding to weak Py tracts characteristic of so-called AG-dependent pre-mRNAs. U2AF(35) has also been implicated in arginine-serine (RS) domain-mediated bridging interactions with splicing factors of the SR protein family bound to exonic splicing enhancers (ESE), and these interactions can also stabilize U2AF(65) binding. Complementation of the splicing activity of nuclear extracts depleted of U2AF by chromatography in oligo(dT)-cellulose requires, for some pre-mRNAs, only the presence of U2AF(65). In contrast, splicing of a mouse immunoglobulin M (IgM) M1-M2 pre-mRNA requires both U2AF subunits. In this report we have investigated the sequence elements (e.g., Py tract strength, 3' splice site AG, ESE) responsible for the U2AF(35) dependence of IgM. The results indicate that (i) the IgM substrate is an AG-dependent pre-mRNA, (ii) U2AF(35) dependence correlates with AG dependence, and (iii) the identity of the first nucleotide of exon 2 is important for U2AF(35) function. In contrast, RS domain-mediated interactions with SR proteins bound to the ESE appear to be dispensable, because the purine-rich ESE present in exon M2 is not essential for U2AF(35) activity and because a truncation mutant of U2AF(35) consisting only of the pseudo-RNA recognition motif domain and lacking the RS domain is active in our complementation assays. While some of the effects of U2AF(35) can be explained in terms of enhanced U2AF(65) binding, other activities of U2AF(35) do not correlate with increased cross-linking of U2AF(65) to the Py tract. Collectively, the results argue that interaction of U2AF(35) with a consensus 3' splice site triggers events in spliceosome assembly in addition to stabilizing U2AF(65) binding, thus revealing a dual function for U2AF(35) in pre-mRNA splicing.

Kinetic role for mammalian SF1/BBP in spliceosome assembly and function after polypyrimidine tract recognition by U2AF

Two sequences important for pre-mRNA splicing precede the 3' end of introns in higher eukaryotes, the branch point (BP) and the polypyrimidine (Py) tract. Initial recognition of these signals involves cooperative binding of the splicing factor SF1/mammalian branch point binding protein (mBBP) to the BP and of U2AF(65) to the Py tract. Both factors are required for recruitment of the U2 small nuclear ribonucleoprotein particle (U2 snRNP) to the BP in reactions reconstituted from purified components. In contrast, extensive depletion of ST1/BBP in Saccharomyces cerevisiae does not compromise spliceosome assembly or splicing significantly. As BP sequences are less conserved in mammals, these discrepancies could reflect more stringent requirements for SF1/BBP in this system. We report here that extensive depletion of SF1/mBBP from nuclear extracts of HeLa cells results in only modest reduction of their activity in spliceosome assembly and splicing. Some of these effects reflect differences in the kinetics of U2 snRNP binding. Although U2AF(65) binding was reduced in the depleted extracts, the defects caused by SF1/mBBP depletion could not be fully restored by an increase in occupancy of the Py tract by exogenously added U2AF(65), arguing for a role of SF1/mBBP in U2 snRNP recruitment distinct from promoting U2AF(65) binding.

[Vesical diseases: accuracy of imaging modalities]

Vesical disorders are numerous. For tumoral processes, the role of imaging modalities is limited to the loco-regional extension. In certain rare cases of benign tumors, precise diagnosis can be evocated. Nowadays, urinary insufficiency is explored by dynamic MRI. It provides a complete assessment of the whole muscular and visceral compartments of the pelvic cavity.

[Helical CT of urinary tract: clinical applications]

Helical CT is the most useful imaging modality to evaluate kidney diseases. Different imaging protocols are used to assess the correct diagnosis in each clinical situation. The nephrographic phase (between 90 and 100 s of delay after injection) is more accurate than the cortical phase (between 30 and 40 s of delay) to depict and characterise small renal masses. Multiplanar and 3D reconstruction are useful to plan partial kidney surgery or percutaneous surgery of lithiasis. In emergency, spiral CT, if available, is suitable to assess renal colic. Spiral CT is the best modality to evaluate traumatic kidney.

A model of stepwise isovolaemic blood exchange in anaesthetised, spontaneously breathing rats to evaluate the oxygen transport efficiency of artificial oxygen carriers

Our research pursues the production of hypo-oncotic artificial oxygen carriers, based on artificial covalently cross-linked hyperpolymeric mammalian haemoglobins. To evaluate their in vivo efficiency in oxygen delivery to the tissue we developed a small animal model of stepwise isovolaemic blood exchange in anaesthetised, spontaneously breathing rats. With the aid of a two-way respiratory micro valve for small animals the overall oxygen uptake by the tissue of the animal can be determined. Measurements of oxygen contents in arterial and mixed venous blood and of some further blood parameters together with known oxygen-binding characteristics of artificial and native oxygen carriers, permits the determination of the way the two oxygen carriers contribute to the overall oxygen uptake. These so-called partial oxygen net to transport rates (i.e. partial oxygen uptakes), related to the corresponding intravascular mass flow of the transporters, are characteristic measures of the efficiency of the oxygen transporter, the so-called oxygen transport quality. Other biological indicators for an adequate oxygen supply are oxygen-dependent changes of ventilation, cardiac output, heart rate, and systemic vascular resistance. The performance of artificial oxygen carriers is elucidated by a comparison with experimental results from the analogous treatment of rats with non oxygen-transporting plasma expanders.