Multivariate independent prognostic factors in endometrial carcinoma: A clinicopathologic study in 181 patients

The aim of this study was to evaluate the biologic outcome of endometrial carcinomas as compared to clinical and pathologic parameters and to identify multivariate independent prognostic factors. Charts were abstracted from patients with endometrial carcinoma from 1985 to 1995. Data on clinicopathologic variables, adjuvant treatment, site of recurrence, and survival were collected. χ2 test was used to test association between variables. Kaplan-Maier method was used for survival analysis and Cox proportional hazards model for multiple regression analysis. Univariate analysis revealed that FIGO stage, tumor grade, depth of myometrial invasion, biochemical analysis of progesterone receptor status, age, additional diabetes mellitus, lymph node metastasis, and type of tumor were significantly associated with the overall-survival. For disease-free interval, FIGO stage, tumor grade, depth of myometrial invasion, biochemical analysis of progesterone receptor status, lymph node metastasis, and type of tumor were also significantly associated. Multivariate analysis revealed that FIGO stage, tumor grading, tumor type, depth of myometrial invasion, and biochemically measured progesterone receptor status were associated significantly with overall survival. A significant correlation as independent prognostic factors were also seen for recurrence free interval for FIGO stage, tumor grade, and biochemical progesterone receptor status. In multivariate statistical analysis we identified FIGO stage, tumor type, tumor grade, biochemical analysis of progesterone receptor status, and depth of myometrial invasion as independent prognostic factors for overall survival, and FIGO stage, biochemical analysis of progesterone receptor status, and tumor grade as independent prognostic factors for recurrence-free interval.

The metabolism of 2-trifluormethylaniline and its acetanilide in the rat by 19F NMR monitored enzyme hydrolysis and 1H/19F HPLC-NMR spectroscopy

The urinary excretion profile and identity of the metabolites of 2-trifluoromethyl aniline (2-TFMA) and 2-trifluoromethyl acetanilide (2-TFMAc), following i.p. administration to the rat at 50 mg kg(-1), were determined using a combination of 19F NMR monitored enzyme hydrolysis, SPEC-MS and 19F/1H HPLC-NMR. A total recovery of approximately 96.4% of the dose was excreted into the urine as seven metabolites. The major routes of metabolism were N-conjugation (glucuronidation), and ring-hydroxylation followed by sulphation (and to a lesser extent glucuronidation). The major metabolites excreted into the urine for both compounds were a labile N-conjugated metabolite (a postulated N-glucuronide) and a sulphated ring-hydroxylated metabolite (a postulated 4-amino-5-trifluoromethylphenyl sulphate) following dosing of 2-TFMA. These accounted for approximately 53.0 and 31.5% of the dose, respectively. This study identifies problems on sample component instability in the preparation and analysis procedures.

Extracellular invertase: key metabolic enzyme and PR protein

Extracellular invertase is the key enzyme of an apoplasmic phloem unloading pathway and catalyses the hydrolytic cleavage of the transport sugar sucrose released into the apoplast. This mechanism contributes to long-distance assimilate transport, provides the substrate to sustain heterotrophic growth and generates metabolic signals known to effect various processes of primary metabolism and defence responses. The essential function of extracellular invertase for supplying carbohydrates to sink organs was demonstrated by the finding that antisense repression of an anther-specific isoenzyme provides an efficient method for metabolic engineering of male sterility. The regulation of extracellular invertase by all classes of phytohormones indicates an essential link between the molecular mechanism of phytohormone action and primary metabolism. The up-regulation of extracellular invertase appears to be a common response to various biotic and abiotic stress-related stimuli such as pathogen infection and salt stress, in addition to specific stress-related reactions. Based on the observed co-ordinated regulation of source/sink relations and defence responses by sugars and stress-related stimuli, the identified activation of distinct subsets of MAP kinases provides a mechanism for signal integration and distribution within such complex networks. Sucrose derivatives not synthesized by higher plants, such as turanose, were shown to elicit responses distinctly different from metabolizable sugars and are rather perceived as stress-related stimuli.

Medical THz imaging: an investigation of histo-pathological samples

We present a THz investigation of histo-pathological samples including the larynx of a pig and a human liver with metastasis. Our measurements show that different types of tissue can be clearly distinguished in THz transmission images, either within a single image or by a comparison of images obtained for different frequency windows. This leads to the problem that images obtained for different frequencies inherently have a different spatial resolution. An image obtained from two such images by a simple mathematical operation may contain artefacts. We discuss measures to deal with this problem. Furthermore, we investigate the possibility of improving the spatial resolution of THz images. Finally, we present a cw THz imaging system based on a photomixer and an external cavity semiconductor laser that allows for simultaneous two-mode operation. The cw system is less expensive and more compact than conventional time-domain imaging systems.

[Valence of immunohistochemical analysis of endometrial carcinoma biopsy specimen]

OBJECTIVE

We compared immunohistological examination of endometrium biopsy specimen with the results of the immunohistological examination of tumor specimen to analyse the valence of this preoperative examination according to the clinico-pathological findings and overall-survival.

MATERIAL AND METHOD

Between 1985 and 1995 193 women were treated of an endometrial carcinoma at the University hospital Mainz. In this group we evaluated 41 patients with enough preoperative endometrial biopsy material for a retrospective immunohistochemical analysis and complete follow-up data. The materials from diagnostic curettage were stained and analysed for oestrogen and progesterone receptor status and for MiB-1. The results were statistically analysed using Logrank-test for overall survival.

RESULTS

The mean follow-up time was 49 months. We found a significant correlation between staining results of oestrogen (p-value = 0.0005) and progesterone (p-value=0.0003) receptor status with overall survival as well as for MiB-1 (p-value=0.05). The correlation of staining results between biopsy specimen results and tumor material from hysterectomy was 84-85 %.

CONCLUSION

These well known prognostic factors are measurable on biopsy specimen material in same quality and high valence as on hysterectomy material.

Evidence for spin-charge separation in quasi-one-dimensional organic conductors

Interacting conduction electrons are usually described within Fermi-liquid theory, which states that, in spite of strong interactions, the low-energy excitations are electron-like quasiparticles with charge and spin. In recent years there has been tremendous interest in conducting systems that are not Fermi liquids, motivated by the observation of highly anomalous metallic states in various materials, most notably the copper oxide superconductors. Non-Fermi-liquid behaviour is generic to one-dimensional interacting electron systems, which are predicted to be Luttinger liquids. One of their key properties is spin-charge separation: instead of quasiparticles, collective excitations of charge (with no spin) and spin (with no charge) are formed, which move independently and at different velocities. However, experimental confirmation of spin-charge separation remains a challenge. Here we report experiments probing the charge and heat current in quasi-one-dimensional conductors--the organic Bechgaard salts. It was found that the charge and spin excitations have distinctly different thermal conductivities, which gives strong evidence for spin-charge separation. The spin excitations have a much larger thermal conductivity than the charge excitations, which indicates that the coupling of the charge excitations to the lattice is important.

mRNA detection of tumor-rejection genes BAGE, GAGE, and MAGE in peritoneal fluid from patients with ovarian carcinoma as a potential diagnostic tool

BACKGROUND

It has been found that the members of the BAGE, MAGE, and GAGE gene families are expressed almost exclusively in neoplastic tissues. Normal tissues, except testis and placenta, are negative. Therefore, the expression of these genes may serve as a useful diagnostic marker in detecting malignant disease. The involvement of the serous cavities by malignant neoplasms has important therapeutic and prognostic implications. Accordingly, the diagnosis of peritoneal spread of ovarian carcinoma plays an important role for both initial and second-look staging procedures. In some patients, however, a definite diagnosis cannot be established by morphologic or immunocytologic examination alone. Detection of tumor specific gene expression may be a sensitive additional tool in these settings.

METHODS

The authors studied the gene expression observed in 44 ascites specimens. Gene expression was evaluated by reverse transcription-polymerase chain reaction analysis and sequencing.

RESULTS

Of 44 ascites specimens, the expression of BAGE, MAGE-1, MAGE-3, and GAGE-1/2 was recognized in 17 specimens (63%), 2 specimens (7%), 8 specimens (30%), and 8 specimens (30%) with histologically proven ovarian carcinoma, respectively. Expression of the MAGE and GAGE genes was not observed in patients with nonneoplastic disease, whereas BAGE expression was seen in one patient with cirrhosis.

CONCLUSIONS

These findings show that testing for BAGE, GAGE-1/2, MAGE-1, and MAGE-3 transcriptional activity in ascites specimens results in high sensitivity in diagnosing malignant ascites.

The metabolism of 4-trifluoromethoxyaniline and [13C]-4-trifluoromethoxyacetanilide in the rat: detection and identification of metabolites excreted in the urine by NMR and HPLC-NMR

A combination of 19F, 1H NMR and HPLC-NMR spectroscopic approaches have been used to quantify and identify the urinary-excreted metabolites of 4-trifluoromethoxyaniline (4-TFMeA) and its [13C]-labelled acetanilide following i.p. administration at 50 mg/kg to rats. The major metabolite excreted in the urine for both compounds was a sulphated ring-hydroxylated metabolite (either 2- or 3-trifluoromethyl-5-aminosulphate) which accounted for approximately 32.3% of the dose following the administration of 4-TFMeA and approximately 29.9% following dosing of the acetanilide. The trifluoromethoxy-substituent appeared to be metabolically stable, with no evidence of O-detrifluoromethylation. There was no evidence of the excretion of N-oxanilic acids in urine, of the type seen with 4-trifluoromethylaniline.

Fine needle aspiration of the thyroid: can an image processing system improve differentiation?

OBJECTIVE

To differentiate thyroid nodules by means of fine needle aspiration with subsequent computer-aided diagnosis.

STUDY DESIGN

Fine needle aspiration biopsies obtained from 137 patients for whom histopathologic diagnosis was available were investigated: 16 hyperplastic nodules (12%), 39 adenomas (28%), 25 follicular thyroid carcinomas (18%), 19 follicular variants of papillary thyroid carcinoma (14%) and 38 papillary thyroid carcinomas (28%). From each stained specimen 100 cell scenes were scanned and analyzed, constituting a total of 62,325 cell images.

RESULTS

All the entities described could be well discriminated from each other by automated image analysis methods. Both the diagnosis of tumor type and the differentiation between benign and malignant could be achieved with a sensitivity of .98.

CONCLUSION

With only 7-10 calculated cell features (texture line analysis) and classification with decision trees, a tool for high-quality cell image diagnosis is available. Subtypes of cells characterized by the calculated features could be found in all the specimens and could be assigned to the malignancies with high statistical significance. The method increases the relevance of image processing as an additional diagnostic tool for cytologic examination of thyroid nodules.

Influence of rhTSH on [(18)F]fluorodeoxyglucose uptake by differentiated thyroid carcinoma

The influence of serum TSH levels on fluorine-18 fluorodeoxyglucose (FDG) uptake by recurrences or metastases of differentiated thyroid carcinomas has not yet been clarified. The aim of this study was to ascertain whether the administration of recombinant human thyrotropin (rhTSH) stimulates FDG uptake by such lesions. In this prospective study, 30 patients with positive or equivocal thyroglobulin (Tg) levels and negative or equivocal iodine-131 and/or morphological imaging results (ultrasound, MRI, CT) underwent FDG positron emission tomography (PET) under exogenous TSH suppression and under exogenous TSH stimulation of serum levels by injection of rhTSH. The mean interval between the FDG-PET studies under these two conditions was 9.3+/-8.8 weeks. Serum TSH levels and free thyroid hormones were determined on each occasion. FDG uptake was quantitated using tumour to background ratios (TBRs) and standardised uptake values (SUVs). Under TSH suppression there was focal FDG accumulation in nine subjects (22 tumour-like lesions). The total number of foci was 45. After exogenous TSH stimulation, the number of patients in whom FDG foci were detected was 19, and the number of foci identified was 82 (78 tumour-like lesions). TBR of regions showing positive FDG contrast with either of the modalities averaged 2.54+/-1.89, and under stimulated TSH levels, 5.51+/-2.99 ( P<0.0001). Corresponding SUVs were 2.05+/-1.45 versus 2.77+/-1.58 ( P<0.001). In a small number ( n=4) of foci related to inflammatory lymph nodes, TBR and SUV were only marginally increased under TSH stimulation (2.01+/-0.38 and 1.07+/-0.38, respectively), and the values did not differ significantly from those obtained under suppression. These results provide the first direct evidence that TSH stimulates FDG uptake by differentiated thyroid carcinoma and that, therefore, FDG-PET is more accurate under rhTSH than under suppression.

[Circumscribed vasculitis with posterior infarct in Hashimoto encephalopathy]

The aetiology of Hashimoto's encephalopathy is still unknown. A 52-year-old woman with so far unspecific thyroid disorder presented with acute onset of right-sided sensory loss and visual disturbances. The neurological examination revealed a right upper quadrant anopsia and subtle right-sided sensory loss and weakness. The cranial MRI showed a left-sided cerebral infarction. MR angiography demonstrated a stenosis of the proximal segment of the left posterior cerebral artery, which was confirmed by conventional catheter angiography. The patient had no cardiovascular risk factors, no signs of systemic vasculitis, and no thromboembolic disorder. Thyroid function tests showed a subclinical hypothyroidism with plasma TSH level of 12.0 mU/ml, and thyroid antibodies were markedly elevated (hTG-AB 3390 U/ml, TPO-AB > 8000 U/ml). Typical features of Hashimoto's disease were demonstrated by ultrasound and scintigraphic examination of the thyroid gland. To the best of our knowledge, this is the first description of Hashimoto encephalopathy with localised vasculitis of the posterior cerebral arteries and left posterior infarction. It could be shown that the MR angiogram is a feasible tool to demonstrate regression of the vasculitis under glucocorticoid therapy.

Phase transformation of ammonium monomolybdate. The structure of the low temperature modification, (NH4)2[MoO4] (mP60, P21/a)

(NH4)2[MoO4] (mS60) undergoes on cooling a phase transition at 190 K. The investigation of this phase transition by means of time and temperature resolved X-ray powder diffraction showed that the phase transition appears on heating at a temperature of 250 K. From this hysteresis and the abrupt changes in the peak positions of the diffractograms it is assumed that this is a first order transition. A diffractogram of the low temperature modification was recorded between 10° and 100° in 2θ. The structure was determined using direct methods and was refined by Rietveld methods. The low temperature modification of (NH4)2[MoO4] (mP60, P21/a) crystallizes in space group P21/a (No. 14) and lattice constants a = 767.57(5) pm, b = 1120.53(7) pm, c = 712.64(4) pm and β = 115.727(2)°.

Expression of angiopoietin-1 and its receptor TEK in hematopoietic cells from patients with myeloid leukemia

Apart from endothelial cells, the receptor tyrosine kinase TEK/Tie-2 is also expressed by primitive hematopoietic stem cells. While the role of this receptor and its ligand angiopoietin-1 (ang-1) during angiogenesis has been intensively studied before, little is known about their function in normal or malignant hematopoiesis. Recently several studies suggested that TEK plays an important role in the proliferation of primitive hematopoietic cells. We, therefore, analyzed blood cells of healthy donors and leukemia patients for expression of TEK and ang-1 by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and Northern blotting. We found an increased expression of the receptor and its ligand in 11 of 17 cases of acute and chronic myeloid leukemia (CML) but not in four lymphocytic leukemias or five myeloid leukemias in remission. Abundant ang-1 message could also be detected in 4/6 myeloid and 1/9 cell lines of lymphocytic origin, but only one cell line co-expressed the TEK receptor, suggesting that ang-1 and TEK were probably expressed by different subsets of cells in the leukemic samples. Recently, several studies have indicated that angiogenic factors like ang-1 and vascular endothelial growth factor can enhance the proliferation of normal and malignant hematopoietic cells. The expression of both the TEK receptor and its ligand in acute myeloid leukemia (AML) and CML patients might, therefore, suggest an involvement of these genes in the pathogenesis of myeloproliferative disorders.

Monitoring isotretinoin therapy in thyroid cancer using 18F-FDG PET

Treatment with isotretinoin (13-cis-retinoic acid, 13-cis-RA) is a recent additional option in advanced, otherwise intractable differentiated thyroid cancers. The aim of this study was to evaluate fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) in the prediction and the monitoring of response to 13-cis-RA therapy. Twenty-one patients with advanced differentiated thyroid cancers were investigated using 18F-FDG PET and iodine-131 whole-body scans before and 3, 6 and 9 months after initiation of 13-cis-RA therapy. After 9 months, 13-cis-RA treatment was discontinued and imaging procedures repeated 3 months later. Average 18F-FDG uptake (SUV) decreased significantly during 13-cis-RA therapy but subsequently increased in five of eight patients after withdrawal of 13-cis-RA. 18F-FDG uptake (SUV) 3 months after onset of 13-cis-RA therapy was significantly lower in patients who developed increased 131I uptake in their tumour sites than in patients with no subsequent increase in 131I uptake. There was no relationship between serum thyroglobulin level on the one hand and simultaneously measured 131I or 18F-FDG uptake on the other hand. There was a tendency towards lower 18F-FDG uptake in tumour manifestations with a better outcome. Therefore, 18F-FDG PET at 3 months after the start of treatment promises to differentiate between those patients who will eventually benefit from 13-cis-RA and those who will not. In conclusion, these data indicate that 18F-FDG PET is a useful tool for the evaluation and monitoring of adjuvant therapy with 13-cis-RA in thyroid cancer.

Biokinetics and imaging with the somatostatin receptor PET radioligand (68)Ga-DOTATOC: preliminary data

Somatostatin (SMS) scintigraphy is widely used for the detection and staging of neuroendocrine tumours. Because of its superior imaging properties, there is growing interest in the use of positron emission tomography (PET) technology for SMS scintigraphy. This study addressed the production of gallium-68 DOTATOC, its biokinetics and its clinical performance in detecting SMS-positive tumours and metastases. A preparation protocol was developed, yielding 40% overall incorporation of (68)Ga into the peptide (DOTATOC). After column filtration, the radiochemical purity exceeded 98%. Eight patients with histologically verified carcinoid tumours were injected with 80-250 MBq of this tracer. PET acquisition was initiated immediately after administration and carried out until 3 h post injection. Images were quantitated using standardised uptake values and target to non-target ratios. Prior to (68)Ga-DOTATOC PET, all patients underwent indium-111 octreotide planar and single-photon emission tomographic (SPET) imaging. Arterial activity elimination was bi-exponential, with half-lives of 2.0 (+/-0.3) min and 48 (+/-7) min. No radioactive metabolites were detected within 4 h in serum. Maximal tumour activity accumulation was reached 70+/-20 min post injection. Kidney uptake averaged <50% compared with spleen uptake. Of 40 lesions predefined by computed tomography and/or magnetic resonance imaging, (68)Ga-DOTATOC PET identified 100%, whereas (111)In-octreotide planar and SPET imaging identified only 85%. Tumour to non-tumour ratios ranged from >3:1 for liver ((111)In-octreotide: 1.5:1) to 100:1 for CNS ((111)In-octreotide: 10:1). With (68)Ga-DOTATOC >30% additional lesions were detected. It is concluded that PET using (68)Ga-DOTATOC results in high tumour to non-tumour contrast and low kidney accumulation and yields higher detection rates as compared with (111)In-octreotide scintigraphy.

Novel target genes of the Ah (dioxin) receptor: transcriptional induction of N-myristoyltransferase 2

Dioxins are potent mammalian carcinogens and toxins affecting liver, skin, and immune and reproductive systems. The intracellular Ah receptor, a ligand-dependent transcription factor of the basic region/helix-loop-helix/Per-Ahr/Arnt-Sim homology domain (bHLH-PAS) protein family, mediates responses to dioxins. Target genes of the Ah receptor that mediate dioxin toxicity and carcinogenicity are, however, mostly unknown. We used 5L rat hepatoma cells to identify dioxin-inducible genes by suppression subtractive hybridization. Eleven cDNA fragments were identified that represented novel sequences or genes for which induction by dioxins had not been known. N-myristoyltransferase 2 (NMT2) is one of the later dioxin-inducible genes. Induction of NMT2 was confirmed in livers of mice in vivo. NMT2 induction was a direct consequence of Ah receptor activation in 5L cells. [(3)H]myristic acid incorporation into 5L cell proteins was inducible by dioxins, indicating that protein myristoylation is a regulated rather than a housekeeping function and that NMT activity is limiting in noninduced 5L cells. Here we show for the first time that expression of NMT2 and induced protein myristoyltransferase activity are direct responses to carcinogen exposure. Because inappropriate protein NH(2)-terminal myristoylation appears to play a role in carcinogenesis, induction of NMT2 may play a central role in dioxin carcinogenicity.

Diabetes-associated sustained activation of the transcription factor nuclear factor-kappaB

Activation of the transcription factor nuclear factor-kappaB (NF-kappaB) has been suggested to participate in chronic disorders, such as diabetes and its complications. In contrast to the short and transient activation of NF-kappaB in vitro, we observed a long-lasting sustained activation of NF-kappaB in the absence of decreased IkappaBalpha in mononuclear cells from patients with type 1 diabetes. This was associated with increased transcription of NF-kappaBp65. A comparable increase in NF-kappaBp65 antigen and mRNA was also observed in vascular endothelial cells of diabetic rats. As a mechanism, we propose that binding of ligands such as advanced glycosylation end products (AGEs), members of the S100 family, or amyloid-beta peptide (Abeta) to the transmembrane receptor for AGE (RAGE) results in protein synthesis-dependent sustained activation of NF-kappaB both in vitro and in vivo. Infusion of AGE-albumin into mice bearing a beta-globin reporter transgene under control of NF-kappaB also resulted in prolonged expression of the reporter transgene. In vitro studies showed that RAGE-expressing cells induced sustained translocation of NF-kappaB (p50/p65) from the cytoplasm into the nucleus for >1 week. Sustained NF-kappaB activation by ligands of RAGE was mediated by initial degradation of IkappaB proteins followed by new synthesis of NF-kappaBp65 mRNA and protein in the presence of newly synthesized IkappaBalpha and IkappaBbeta. These data demonstrate that ligands of RAGE can induce sustained activation of NF-kappaB as a result of increased levels of de novo synthesized NF-kappaBp65 overriding endogenous negative feedback mechanisms and thus might contribute to the persistent NF-kappaB activation observed in hyperglycemia and possibly other chronic diseases.

[Endometrial carcinoma in patients with diabetes mellitus]

OBJECTIVE

The purposes of this study were to analyze the relationship between clinical and pathological risk factors in endometrial cancer and additional diabetes mellitus and to clarify the correlation between additional diabetes mellitus and survival of patients with this disease. -

MATERIAL AND METHODS

This analyze included 181 patients with endometrial carcinoma who were treated between 1985 and 1995 at the University hospital Mainz. Patients with sarcoma were excluded. For statistical analysis a chi(2)-test was performed for univariat analysis. A Kaplan-Meier procedure was performed for over all survival and disease free interval and COX-Regression for multivariate analysis of independence. -

RESULTS

The mean follow-up period was 49 months. The mean age was 65 years. 21.8 % of the patients had an additional diabetes mellitus. These patients had a significantly deeper infiltration of the Myometrium (p-value = 0.004) and were more likely to have lymphonode metastasis (p-value = 0.02). -

CONCLUSION

Our results show a correlation between Diabetes mellitus and adverse prognostic factors witch affects by the rate of lymphonode spread and overall survival.

Intraoperative radiofrequency maze ablation for atrial fibrillation: the Berlin modification

BACKGROUND

The Cox-maze procedure combined with an operation for organic heart disease is highly successful in the elimination of chronic atrial fibrillation. However, it prolongs significantly the aortic cross-clamp and operating time. In this study, a simplified left atrial maze procedure, which is a short procedure performed using a surgical radiofrequency ablation probe, is added to elective open heart procedures in patients with atrial fibrillation.

METHODS

Forty-eight adults with atrial fibrillation (duration, 6 months to 36 years) underwent elective open heart operations (isolated valve procedures or coronary artery bypass grafting, n = 27 patients; combined procedures, n = 21 patients) combined with intraoperative radiofrequency ablation of the left atrium. The postoperative follow-up period ranged from 1 to 11 months (mean, 4 months). Possible predictors for persistent postoperative atrial fibrillation were determined among 40 variables by univariate and multivariate analyses.

RESULTS

Intraoperative radiofrequency ablation prolonged the aortic cross-clamp time for 6 to 14 minutes (mean, 11 minutes). Freedom from atrial fibrillation was 100% intraoperatively, 25% at 1 week after operation (12 of 48 patients), 59% at 1 month postoperatively (16 of 27 patients), 64% at 3 months postoperatively (16 of 25 patients), and 92% at 6 months postoperatively (12 of 13 patients). The only predictor of postoperative atrial fibrillation was the presence of coronary artery disease (odds ratio, 7.5; 80% confidence interval, 2.24-25.13).

CONCLUSIONS

Intraoperative radiofrequency ablation of the left atrium combined with an operation for organic heart disease effectively eliminates atrial fibrillation without significant prolongation of the aortic cross-clamp and operative time. The presence of coronary artery disease decreases the success rate during the first 6 postoperative months.

Strong damping of phononic heat current by magnetic excitations in SrCu2(BO3)(2)

Measurements of the thermal conductivity as a function of temperature and magnetic field in the 2D dimer spin system SrCu2(BO3)(2) are presented. In zero magnetic field the thermal conductivity along and perpendicular to the magnetic planes shows a pronounced double-peak structure as a function of temperature. The low-temperature maximum is drastically suppressed with increasing magnetic field. Our quantitative analysis reveals that the heat current is due to phonons and that the double-peak structure arises from pronounced resonant scattering of phonons by magnetic excitations.