[Results of an automatic evaluation of test images according to PAS 1054 and IEC 6220-1-2 on different types of digital mammographic units]

AIM

To test whether image processing methods are suitable for detecting differences in the image quality of digital mammography units and whether the methods are more sensitive than visual test methods like the evaluation of CDMAM test images.

METHODS

Test images according to PAS 1054 were acquired with CR and DR systems and analyzed automatically. Only parameters were used that are obligatory for calculating the detective quantum efficiency (DQE), the noise power spectrum (NPS), the spatial resolution (MTF, modulation transfer function), and the averaged glandular dose (AGD). The derived value, the NEQ index, is linked to the noise equivalent quanta (NEQ). Additionally CDMAM test images were acquired and evaluated at one CR and one DR system.

RESULTS

The accuracy of the evaluated values is in the range below of 2 %. The accuracy requirements are fulfilled to establish values for detecting changes in image quality related to changes in dose no greater than one exposure value. If a visual evaluation of test images is used, a significant difference in image quality can only be detected when the dose is doubled.

CONCLUSION

A method is proposed for establishing dose-correlated tolerances for values used in constancy and acceptance tests independently of the type of mammography unit (CR and DR systems). A method which abstains from visual tests for establishing the performance of digital mammography units could be used in acceptance tests.

Application of genetic screening in families with hereditary medullary thyroid carcinoma

In 34 families out of 35 with hereditary medullary thyroid cancer a mutation in the RET proto-ongene could be identified. In 84 family members gene carrier state could be proven, in 75 family members gene carrier state could be excluded. The majority of gene carriers (67 out of 84) were symptomatic while 17 gene carriers were diagnosed in a presymptomatic state. 9 of the 17 presymptomatic gene carriers had prophylactic thyroidectomy. On histological examination C-cell hyperplasia or multifocal microcarcinomas could be proven. In one of our families with familial MTC no germline mutation in the RET gene could be detected. In this family pentagastrintests and indirect genotyping are necessary. Four family members of MEN 2A families have had thyroidectomy on the basis of pentagastrin testing and now proved not to be gene carriers. The application of genetic testing in families with hereditary thyroid carcinoma has further improved management in these families - it is the first step in the evaluation of family members at risk.

Rotational cooling of HD+ molecular ions by superelastic collisions with electrons

Merging an HD+ beam with velocity matched electrons in a heavy ion storage ring we observed rapid cooling of the rotational excitations of the HD+ ions by superelastic collisions (SEC) with the electrons. The cooling process is well described using theoretical SEC rate coefficients obtained by combining the molecular R-matrix approach with the adiabatic nuclei rotation approximation. We verify the DeltaJ=-2 SEC rate coefficients, which are predicted to be dominant as opposed to the DeltaJ=-1 rates and to amount to (1-2)x10;{-6} cm;{3} s;{-1} for initial angular momentum states with J< or =7, to within 30%.

Anisotropy and molecular rotation in resonant low-energy dissociative recombination

Angular fragment distributions from the dissociative recombination (DR) of HD(+) were measured with well directed monochromatic low-energy electrons over a dense grid of collision energies from 7 to 35 meV, where pronounced rovibrational Feshbach resonances occur. Significant higher-order anisotropies are found in the distributions, whose size varies along energy in a partial correlation with the relative DR rate from fast-rotating molecules. This may indicate a breakdown of the nonrotation assumption so far applied to predict angular DR fragment distributions.

Effects of molecular rotation in low-energy electron collisions of H3+

Measurements on the energetic structure of the dissociative recombination rate coefficient in the millielectronvolt range are described for H3+ ions produced in the lowest rotational levels by collisional cooling and stored as a fast beam in the magnetic storage ring TSR (Test Storage Ring). The observed resonant structure is consistent with that found previously at the storage ring facility CRYRING in Stockholm, Sweden; theoretical predictions yield good agreement on the overall size of the rate coefficient, but do not reproduce the detailed structure. First studies on the nuclear spin symmetry influencing the lowest level populations show a small effect different from the theoretical predictions. Heating processes in the residual gas and by collisions with energetic electrons, as well as cooling owing to interaction with cold electrons, were observed in long-time storage experiments, using the low-energy dissociative recombination rate coefficient as a probe, and their consistency with the recent cold H3+ measurements is discussed.

Long-term outcome in 46 gene carriers of hereditary medullary thyroid carcinoma after prophylactic thyroidectomy: impact of individual RET genotype

OBJECTIVE

In children with RET proto-oncogene mutation, curative treatment of medullary thyroid carcinoma (MTC) is possible by prophylactic thyroidectomy. Recommendations on the timing and extent of thyroidectomy are based upon a model that utilises genotype-phenotype correlations to stratify mutations into three risk groups.

DESIGN

We evaluated the long-term outcome (mean follow-up 6.4 years, 15 patients more than 10 years, 26 patients more than 5 years) of operated gene carriers stratified into two risk groups (levels 1 and 2) based on the biological aggressiveness of MTC.

RESULTS

In 46 RET gene carriers, prophylactic thyroidectomy was carried out between the ages of 4 and 21 years. Level 1 mutations were harboured by 11 patients (codons 790, 791, 804 and 891). Histology was completely normal in two patients; in seven patients C-cell hyperplasia (CCH) and in two patients T1 tumours were diagnosed. All patients with level 1 mutations were cured. Level 2 mutations were harboured by 35 patients (codons 618, 620, 630 and 634). Histology of these patients showed CCH in 11 patients, T1 tumours in 21, T2 tumour in 1, T3 tumour in 1 and Tx in 1 patient. Histology showed no lymph node involvement. Five patients with level 2 mutations failed to be cured; in two patients, persistence of MTC was diagnosed directly after thyroidectomy and in three during follow-up. In two patients carrying a 634 mutation, other endocrinopathies (hyperparathyroidism and bilateral pheochromocytoma) manifested during follow-up.

CONCLUSIONS

If prophylactic thyroidectomy is done at early ages, cure rate is high. Timing and extent of prophylactic thyroidectomy can be modified by individual RET mutation.

High-resolution dissociative recombination of cold H3+and first evidence for nuclear spin effects

The energy-resolved rate coefficient for the dissociative recombination (DR) of H(3)(+) with slow electrons has been measured by the storage-ring method using an ion beam produced from a radiofrequency multipole ion trap, employing buffer-gas cooling at 13 K. The electron energy spread of the merged-beams measurement is reduced to 500 microeV by using a cryogenic GaAs photocathode. This and a previous cold- measurement jointly confirm the capability of ion storage rings, with suitable ion sources, to store and investigate H(3)(+) in the two lowest, (J,G) = (1,1) and (1,0) rotational states prevailing also in cold interstellar matter. The use of para-H(2) in the ion source, expected to enhance para-H(3)(+) in the stored ion beam, is found to increase the DR rate coefficient at meV electron energies.

Evidence for subthermal rotational populations in stored molecular ions through state-dependent dissociative recombination

We demonstrate that the dissociative recombination of D2H+ with low-energy electrons depends on the rotational energy of the molecular ion such that highly excited ions have a larger rate coefficient than colder ones. Observations on an ion beam continuously interacting with electrons at low relative velocity indicate that excited rotational levels are preferentially depleted which, in competition with radiative heating due to blackbody radiation, provides an opportunity for controlling the rotational temperature of stored molecules.

Expression of ryanodine receptor type 3 and TRP channels in endothelial cells: comparison of in situ and cultured human endothelial cells

OBJECTIVE

Ca(2+) mobilization plays an important role in endothelial function by stimulating Ca(2+)-dependent synthesis of vasodilating factors. In addition to inositol-1,4,5-trisphosphate (InsP(3)) mediated Ca(2+) mobilization, Ca(2+) release from ryanodine-sensitive pools and Ca(2+)-influx through TRP channels have been suggested to be important in endothelial Ca(2+)-signaling. However, the function and molecular identity of TRP channels and ryanodine receptors in human endothelium in situ are still elusive. We hypothesized that expression of ryanodine-receptors (RyR) and TRP channels differs between human endothelium in situ and in cultured cells.

METHODS

By combining single-cell RT-PCR and patch-clamp techniques, expression of RyR and TRP channels was determined in situ in endothelial cells of human mesenteric artery (HMAECs) obtained from patients undergoing bowel resection and in the endothelial cell line EA.hy926.

RESULTS

At the single cell level, expression of RyR 3 was detected in 25 and 5% of HMAECs and EA.hy926 samples, respectively. Expression of the RyR 1 and 2 was not detected in either HMAECs or EA.hy926. In patch-clamp experiments in HMAECs, applications of caffeine (0.5 mM) induced sustained hyperpolarization mediated by activation of Ca(2+)-activated K channels. In EA.hy926, caffeine-induced hyperpolarization was not detected. Single HMAECs expressed the TRP genes, TRP1 and TRP3, but not TRP 4 and 6. The TRP1 was the predominantly expressed TRP gene in HMAECs in situ whereas TRP3 expression was rarely detected. EA.hy926 expressed only TRP1. In patch clamp experiments in HMAECs, Ca(2+)-store depletion activated non-selective cation currents leading to Ca(2+) entry.

CONCLUSIONS

Our findings suggest that, in addition to InsP(3) mediated Ca(2+) release, Ca(2+) release from ryanodine-sensitive stores mediated by RyR3 and Ca(2+) entry through TRP1 might represent important components of endothelial Ca(2+) signaling in situ and thereby of endothelial function in intact human blood vessels.

Effect of fluid resuscitation with and without endothelin A receptor blockade on hemoconcentration and organ function in experimental pancreatitis

BACKGROUND

Intravascular fluid loss contributes to pancreatitis-associated multiple organ dysfunction and is thus a major target for therapy in this life-threatening disease.

AIM

To evaluate intravascular fluid loss and extravascular fluid sequestration together with cardiorespiratory and renal function in a well-established rat model of severe acute pancreatitis (AP) and to investigate the effect of fluid resuscitation with and without endothelin receptor A blockade on these parameters.

METHOD

Induction of AP in rats by a standardized bile salt infusion into the pancreatic duct and intravenous cerulein hyperstimulation. Six hours after AP induction, animals were randomized into 4 groups to receive (1) no therapy; (2) 4 ml/kg/h Ringer's lactate (RL) i.v.; (3) 8 ml/kg/h RL i.v., or (4) 4 ml/kg/h RL plus an endothelin receptor antagonist. Target parameters measured before and after AP induction and during the 24-hour observation period included: mean arterial blood pressure, heart rate, hematocrit, arterial blood gases, urine production, ascites and pleural effusions.

RESULTS

After 6 h, all animals presented with severe hemoconcentration (hematocrit >57%) and oliguria (<0.5 ml/6 h). Cardiorespiratory parameters were within the normal range. Up to 12 h after AP induction, animals without therapy had an increased hematocrit and oliguria and developed metabolic acidosis. Animals receiving fluid resuscitation had a significant drop in hematocrit and maintained compensated blood gas values. A significant increase in urine production was only observed in animals given 8 mg/kg/h RL. Between 12 and 24 h, urine production significantly increased with fluid resuscitation and respiratory parameters stabilized except for animals treated with 8 ml/kg/h RL which developed arterial hypoxia and hypercapnia.

CONCLUSIONS

Intravascular fluid loss and extravascular fluid sequestration together with decreased urine production characterize the early phase of this model of severe AP. Massive fluid resuscitation necessary for increasing urine output may lead to respiratory distress. Reduction of intravascular fluid loss by endothelin receptor blockade is associated with improved renal and respiratory function.

Expression of functional GABAA receptors in isolated human insulinoma cells

Pancreatic islets contain and release high concentrations of GABA. GABA is thought to play a paracrine role in beta-cells. Searching for a paracrine function of GABA in neoplastic beta-cells we performed patch-clamp studies in isolated human insulinoma cells. We show that human insulinoma cells can express functional GABAA receptors. Activation of GABAA receptors caused a reversible membrane depolarization in a subgroup of insulinoma cells. Membrane depolarization resulted in transmembraneous calcium influx through voltage-gated calcium channels and stimulation of insulin secretion. Insulin secretion was increased by the GABAA receptor agonist muscimol (50 microM) by about 280%. Thus, GABAA receptors can be expressed in human insulinoma cells and can regulate their insulin release.

Laser-induced thermotherapy for the treatment of liver metastasis. Correlation of gadolinium-DTPA-enhanced MRI with histomorphologic findings to determine criteria for follow-up monitoring

PURPOSE

To evaluate gadolinium (Gd)-diethylenetriamine-pentaacetic-acid (DTPA)-enhanced magnetic resonance imaging (MRI) for follow-up monitoring of laser-induced thermotherapy (LITT) and to determine a useful examination schedule.

METHODS

LITT of the liver was performed in 55 rabbits using a neodymium: yttrium-aluminum-garnet (Nd:YAG) laser (4-W power output, 840-s exposure time). Gd-DTPA MRI and histologic examinations were performed at different times (0-168 days).

RESULTS

Laser-induced lesions underwent regeneration and volume size reduction (69% after 168 days). The correlation coefficient (MR vs. macroscopic analysis) for the mean lesion diameter was r = 0.96. Histology of lesions comprised the four zones that correlated best with MRI findings. Coagulation necroses immediately after LITT was seen as an area of no enhancement on Gd-DTPA MRI. Circular enhancement was first seen 72-96 h after LITT, which was due to early mesenchymal proliferation.

CONCLUSIONS

Gd-DTPA MRI is a good monitoring procedure for LITT. MRI should be performed 24 and 96 h after LITT.

Expression of functional P2-purinergic receptors in primary cultures of human colorectal carcinoma cells

Primary cell cultures of human colorectal carcinomas were established and characterized immunocytochemically. In the isolated cancer cells intracellular Ca2+ concentrations ([Ca2+]i) were measured by the fura-2 method. Stimulation with either extracellular ATP or UTP caused a biphasic rise of [Ca2+]i in a dose-dependent manner and cross-desensitization between both nucleotides was observed. The rank order of potency was ATP >== UTP > ATP-gamma-S > ADP > adenosine which is characteristic for a P2U-receptor subtype. Selective agonists of P1-, or P2X- purinoceptors had no effect on [Ca2+]i. The initial rise in [Ca2+]i was independent of extracellular calcium [Ca2+]e, whereas the second phase was not observed under [Ca2+]e-free conditions suggesting a capacitative Ca2+-entry-mechanism. Intracellular Ca2+ mobilization was proven by use of the Ca2+-ATPase inhibitor thapsigargin. P2U-specific mRNA could be detected by RT-PCR in both colorectal tumor tissues and in the human colorectal cancer cell line HT 29. In HT 29 cells, the hydrolysis-resistant ATP analog ATP-gamma-S inhibited cell proliferation and, also, induced apoptosis in a dose-dependent manner. Thus, human colorectal cancer cells express functional P2U-receptors which may play a role in the regulation of cell proliferation and apoptosis.

Inhibition of L-type calcium channels by octreotide in isolated human neuroendocrine tumor cells of the gut

The observation that somatostatin and its analogue octreotide inhibit the release of various peptide hormones and transmitters from neuroendocrine tumors has stimulated interest in the signal transduction pathway mediated by these compounds. Using the whole cell mode of the patch-clamp technique, we investigated the inhibitory effects of somatostatin and octreotide on voltage-dependent calcium channels (VDCC) in isolated human neuroendocrine tumor cells of the gut. Both peptides dose dependently and reversibly inhibited VDCC. Somatostatin (100 nM) reduced the current amplitude by 38 +/- 19% and 100 nM octreotide by 35 +/- 14%. Human neuroendocrine gut tumor cells preferentially express dihydropyridine-sensitive L-type VDCC, since most of the inward current was sensitive to the dihydropyridine isradipine. The inhibitory effects of isradipine and octreotide were not additive and octreotide had little effect on the isradipine-resistant inward current. Since octrotide selectively binds to the somatostatin receptor subtypes 2 and 5, these results suggest that inhibition of calcium-dependent hormone release by somatostatin from human neuroendocrine gut cells appears to involve somatostatin receptor subtypes 2 and 5, as well as dihydropyridine-sensitive L-type VDCC.

Results and follow-up in eleven MEN 2A gene carriers after prophylactic thyroidectomy

In 11 MEN 2A gene carriers prophylactic thyroidectomy was carried out between the age of 4 to 17 years. All gene carriers had pathological basal and/or pentagastrin stimulated serum calcitonin levels. On histological examination in five patients C-cell hyperplasia (CCH) and in 6 patients medullary microcarcinoma (< 1 cm, mostly multifocally) was shown. No patient had lymph node involvement. There was no recurrent laryngeal nerve damage in these 11 patients and no permanent hypoparathyroidism. After prophylactic thyroidectomy all 11 patients were cured, they showed normal basal and pentagastrin stimulated calcitonin levels. In the follow-up (mean 19 months) under thyroxine substitution therapy in 9 of these 11 patients TSH was at least at one examination out of the normal range. In 2 patients TSH was suppressed, in 1 of these FT3 was slightly elevated. In 7 patients TSH was elevated between 4.9 to 147 microU/ml. The application of genetic testing is save concerning diagnostic accuracy. If prophylactic thyroidectomy is done at early ages cure rate is 100%. Despite this encouraging results thyroxine substitution therapy in the follow-up carries some problems concerning optimal dosage and non-compliance. Therefore TSH has to be estimated in the follow-up every 3 months.

[Intramural pseudodiverticulosis of the esophagus]

Esophageal intramural pseudodiverticulosis is a rare benign condition with the cardinal symptom of dysphagia mostly due to inflammatory strictures. The disease frequently develops in connection with alcohol abuse and esophageal reflux, candidiasis or motility disorders. Characteristic is the radiological visualization of intramural saccular contrast accumulations. We report on five patients with esophageal pseudodiverticulosis endoscopically diagnosed at our hospital within a period of five years. Four of these patients underwent extensive investigations for additional esophageal conditions: Histological/cytological examinations, manometry, pH-metry and endoscopic ultrasonography. These four patients had a pathological reflux with marked esophagitis and inflammatory strictures. We achieved long-lasting therapeutic results with complete relief by bougienage and reflux therapy with additional candidiasis treatment in two and motility treatment in one patient each. The detailed discussion deals with the clinical aspects, characteristics, therapy and pathogenesis.