Addition and removal energies of circular quantum dots.

We present and compare several many-body methods as applied to two-dimensional quantum dots with circular symmetry. We calculate the approximate ground state energy using a harmonic oscillator basis optimized by Hartree-Fock (HF) theory and further improve the ground state energy using two post-HF methods: in-medium similarity renormalization group and coupled cluster with singles and doubles. With the application of quasidegenerate perturbation theory or the equations-of-motion method to the results of the previous two methods, we obtain addition and removal energies as well. Our results are benchmarked against full configuration interaction and diffusion Monte Carlo where available. We examine the rate of convergence and perform extrapolations to the infinite basis limit using a power-law model.

Nucleus-Dependent Valence-Space Approach to Nuclear Structure.

We present a nucleus-dependent valence-space approach for calculating ground and excited states of nuclei, which generalizes the shell-model in-medium similarity renormalization group to an ensemble reference with fractionally filled orbitals. Because the ensemble is used only as a reference, and not to represent physical states, no symmetry restoration is required. This allows us to capture three-nucleon (3N) forces among valence nucleons with a valence-space Hamiltonian specifically targeted to each nucleus of interest. Predicted ground-state energies from carbon through nickel agree with results of other large-space ab initio methods, generally to the 1% level. In addition, we show that this new approach is required in order to obtain convergence for nuclei in the upper p and sd shells. Finally, we address the 1^{+}/3^{+} inversion problem in ^{22}Na and ^{46}V. This approach extends the reach of ab initio nuclear structure calculations to essentially all light- and medium-mass nuclei.

Nonperturbative shell-model interactions from the in-medium similarity renormalization group.

We present the first ab initio construction of valence-space Hamiltonians for medium-mass nuclei based on chiral two- and three-nucleon interactions using the in-medium similarity renormalization group. When applied to the oxygen isotopes, we find experimental ground-state energies are well reproduced, including the flat trend beyond the drip line at (24)O. Similarly, natural-parity spectra in (21,22,23,24)O are in agreement with experiment, and we present predictions for excited states in (25,26)O. The results exhibit a weak dependence on the harmonic-oscillator basis parameter and reproduce spectroscopy within the standard sd valence space.

Expression of somatostatin receptor subtype 2 and subtype 5 in thyroid malignancies.

AIM: To retrospectively analyse the expression of somatostatin receptor subtypes 2 (SSTR 2) and 5 (SSTR 5) in thyroid malignancies, possibly the most relevant subtypes for targeted therapy with somatostatin peptide radioligands. In addition, findings were also correlated with the course of disease. PATIENTS, METHODS: 87 consecutive patients (59 women, 28 men) with thyroid malignancy were included; 52 had papillary carcinoma, 24 follicular carcinoma, six medullary carcinoma, two poorly differentiated carcinoma and three anaplastic carcinoma. After initial therapy 70 (80.5%) patients showed complete remission, 11 (12.6%) patients partial remission with clinical and biochemical signs of residual disease and six (6.9%) patients progressive disease. The immunohistochemical staining results of the primary malignancy for SSTR 2 and SSTR 5 were semiquantitatively assessed and correlated with various outcome parameters. RESULTS: In 10 of 87 (11.49%) thyroid cancer samples SSTR 2 showed positive immunohistochemical expression as compared to 75 of 87 (86.20%) for SSTR 5. All SSTR 2-positive cases expressed SSTR 5. Persistent or recurrent disease was found in 17 of 87 cases (19.54%). Fifty percent (6 /12) of SSTR 5-negative patients showed persistent disease as compared to 14.7 % (11 / 75) of SSTR 5-positive patients: seven of these were exclusively SSTR 5-positive, 4 showed dual expression of SSTR 5 and SSTR 2 (p = 0.01). No case showed only SSTR 2 expression. CONCLUSIONS: SSTR 5 was shown to be the main receptor subtype in the analysed differentiated or anaplastic thyroid malignancies, whereas SSTR 2 was found only in a small percentage. Deficient SSTR expression may indicate higher risk for persistent or recurrent disease after initial therapy. For this reason immunohistochemistry can be considered a prognostic marker which should be further validated in prospective studies.

Immune activation in amyloid-ß-related angiitis correlates with decreased parenchymal amyloid-ß plaque load.

BACKGROUND: Primary angiitis of the central nervous system (PACNS) is a rare but serious condition. A fraction of patients suffering from PACNS concurrently exhibit pronounced cerebral amyloid angiopathy (CAA) which is characterized by deposits of amyloid-ß (Aß) in and around the walls of small and medium-sized arteries of the brain. PACNS with CAA has been identified as a distinct disease entity, termed Aß-related angiitis (ABRA). Evidence points to an immune reaction to vessel wall Aß as the trigger of vasculitis. OBJECTIVE: To investigate whether the inflammatory response to Aß has (1) any effect on the status of immune activation in the brain parenchyma and (2) leads to clearance of Aß from brain parenchyma. METHODS: We studied immune activation and Aß load by quantitative immunohistochemical analysis in brain parenchyma adjacent to affected vessels in 11 ABRA patients and 10 matched CAA controls. RESULTS: ABRA patients showed significantly increased immune activation and decreased Aß loads in the brain parenchyma adjacent to affected vessels. CONCLUSION: Our results are in line with the hypothesis of ABRA being the result of an excessive immune response to Aß and show that this can lead to enhanced clearance of Aß from the brain parenchyma by immune-mediated mechanisms.

In-medium similarity renormalization group for nuclei.

We present a new ab initio method that uses similarity renormalization group (SRG) techniques to continuously diagonalize nuclear many-body Hamiltonians. In contrast with applications of the SRG to two- and three-nucleon interactions in free space, we perform the SRG evolution "in medium" directly in the A-body system of interest. The in-medium approach has the advantage that one can approximately evolve 3,…,A-body operators using only two-body machinery based on normal-ordering techniques. The method is nonperturbative and can be tailored to problems ranging from the diagonalization of closed-shell nuclei to the construction of effective valence-shell Hamiltonians and operators. We present first results for the energies of 4He, 16O, and 40Ca, which have accuracies comparable to coupled-cluster calculations.

Intraoperative frozen section examination of the sentinel lymph node in breast cancer.

AIM OF THE STUDY: Intraoperative frozen section (FS) examination of the Sentinel node (SN) in breast cancer patients is questioned due to the relatively high number of positive SN(s) found in the permanent histological examination. This study reviews the data of the Austrian sentinel node study group on FS examination of the SN and tries to identify patients with a high risk of incorrect negative results. METHODS: 2326 breast cancer patients of the Austrian Sentinel node study group who underwent SN biopsy and intraoperative FS examination of the SN were further analysed for incorrect negative results and clinicopathologic factors indicating a higher rate of incorrect negative results. RESULTS: The FS of the SN was positive in 513 of 2326 patients (22.1%) and negative in 1813 of 2326 patients (77.9%). Permanent histological examination revealed a metastatic SN in 282 of 1813 patients. (incorrect negative rate 15.6%). 158 of 282 patients (56%) were found through H&E serial sectioning, whereas 124 of 282 patients (44%) were only seen in immunohistochemistry. Micrometastases, lobular histology and preoperative chemotherapy were associated with a higher rate of incorrect negative results. CONCLUSION: Incorrect negative results of FS examination are seen in 15% of patients and require a secondary axillary lymph node dissection. The disadvantage of missing a positive SN through FS is by far outweighed by the advantage of a single stage operation in case of a positive SN.

Prediction of non-sentinel lymph node status in breast cancer with a micrometastatic sentinel node.

BACKGROUND: Axillary lymph node dissection (ALND) may not be necessary in women with breast cancer who have micrometastasis in a sentinel node (SN), owing to the low risk of non-SN (NSN) involvement. The aim of this study was to identify a subgroup of women with a micrometastatic SN and a negligible risk of positive NSNs in whom ALND may be avoided. METHODS: Some 237 of 241 women with a macrometastatic SN and 122 of 138 with a micrometastatic SN underwent completion ALND and were compared with respect to NSN involvement. The 122 patients with SN micrometastasis were further analysed to determine factors that could predict the risk of positive NSNs. RESULTS: A total of 121 (51.1 per cent) of 237 women with SN macrometastasis had positive NSNs compared with 22 (18.0 per cent) of 122 with SN micrometastasis (P < 0.001). Multivariate analysis showed that size of SN micrometastasis (odds ratio 3.49 (95 per cent confidence interval (c.i.) 1.32 to 9.23); P = 0.012) and presence of lymphovascular invasion (odds ratio 0.23 (95 per cent c.i. 0.05 to 1.00); P = 0.050) were significantly associated with positive NSNs. SN micrometastasis less than 0.5 mm in diameter combined with absence of lymphovascular invasion was associated with an 8.5 per cent risk of NSN involvement. CONCLUSION: Size of micrometastasis and presence of lymphovascular invasion were significantly related to the risk of finding additional positive axillary lymph nodes when the SN contained only micrometastasis.

[Congo red-negative light chain disease with intractable diarrhea]. / Kongorotnegative Leichtkettenerkrankung mit intraktablen Durchfällen.

A 56-year-old man was admitted due to chronic diarrhea with progressive weight loss (30 kg within 1 year). All results of medical investigations were normal. The suspected diagnosis of a neuroendocrinological neoplasm could not be established; there was also no evidence for a lymphoma or amyloidosis. Chronic diarrhea and weight loss persisted over the ensuing weeks. Additionally, impairment of renal function and heart insufficiency with consecutive pericardial effusion as well as peripheral facial paralysis and peripheral neuropathy could be observed. Six months after hospital admission, the patient died due to progressive multiple organ failure. Postmortem examination revealed normal bone marrow. Only with additional immunohistochemical investigations of all organs could the diagnosis of a systemic Congo red-negative light chain disease be established.

Closure of the cystic duct during laparoscopic cholecystectomy with a new feedback-controlled bipolar sealing system in case of biliary obstruction--an experimental study in pigs.

BACKGROUND/AIMS: The excellent results of new devices like the new bipolar feedback-controlled sealing system (LigaSure) for closure of blood vessels encouraged surgeons to use these instruments for other structures like bile ducts. The aim of this study was to evaluate the feasibility of closure of cystic duct in case of biliary obstruction. METHODOLOGY: Ten domestic pigs underwent laparoscopic cholecystectomy sealing the cystic duct with LigaSure. The common bile duct was closed with an endoclip to create a biliary hypertension. On the 12th postoperative day blood samples were taken for liver enzymes. At autopsy on day 15 the pigs were investigated for bile leaks or biliary peritonitis. The cystic duct was resected for histological examination. RESULTS: Seven pigs survived, one pig died during introduction of anesthesia, one on the 1st and one on the 2nd postoperative day without any findings at the autopsy. One pig out of 7 had a bile leak; the other 6 were without any sign of leakage. Histologically 3 pigs had a regular coagulation zone at the cystic duct, 3 had a total necrosis, one a partial necrosis of the mucosa only. CONCLUSIONS: Though there was only one insufficiency, the feedback-controlled bipolar vessel sealer cannot be recommended for biliary surgery with regard to the high rate of necrosis stated in our experiment.

Low-grade tubular-mucinous renal neoplasms: morphologic, immunohistochemical, and genetic features.

The current classification system of renal tumors is based on morphologic criteria, as supported by genetic findings. We present a group of previously unclassified tumors with similar morphologic and genetic features, suggesting a new entity within renal neoplasms. Seven renal tumors from five patients (ages 31-67 years) were analyzed. All cases were stained with periodic acid-Schiff, Hale's colloidal iron (HCI), and Alcian blue (AB) at pH 2.5/1.0 with and without hyaluronidase (HA) digestion. Immunohistochemical (IHC) stains were performed for CK8, CK18, CK19, vimentin, villin, Tamm-Horsfall protein (THP), renal cell carcinoma marker (RCC), epithelial membrane antigen (EMA), ulex europaeus agglutinin (UEA-1), soy bean agglutinin (SBA), peanut agglutinin (PNA), and MIB-1. Comparative genomic hybridization (CGH) and loss of heterozygosity (LOH) studies were performed on all cases. All tumors showed circumscribed growth, a tubular growth pattern with focal solid areas, no significant nuclear atypia and absence of necrosis, desmoplasia, or inflammation. Abundant extracellular mucin was present. Immunohistochemistry stains support collecting duct origin (EMA+, PNA+, SBA+/-, CK 8/18/19+, vimentin+/-, UEA-1-, RCC-, villin-, THP-). The proliferative rate was low (<1%). CGH showed multiple consistent chromosomal losses (-1,-4, -6, -8, -9, -13, -14, -15, -22). Clinical outcome was favorable, with recurrences but no known distant metastases or death of disease. These findings are distinct from all previously classified renal neoplasms. Our data suggest the presence of a unique tumor entity within tumors of probable collecting duct origin: tubular-mucinous renal tumors of low malignant potential.

A new bipolar feedback-controlled sealing system for closure of the cystic duct and artery.

BACKGROUND: Bile leaks are serious complications after laparoscopic cholecystectomy. The aim of this study was to evaluate the feasibility of closure of the cystic duct with a new feedback-controlled bipolar sealing system (LigaSure). METHODS: Ten domestic pigs underwent open cholecystectomy with the cystic duct and artery dissected and sealed with the new bipolar sealing system (LigaSure). Four and 8 days postoperatively, 5 pigs each were sacrificed and the closure of the cystic duct was evaluated. The cystic stump and the common bile duct were excised for histological examination. RESULTS: None of the pigs had a bile leak or a biliary peritonitis. There were no signs of postoperative bleeding or inflammation in Calot's triangle. Histology showed total necrosis of the cystic duct in the first two pigs due to too much energy used. The remaining specimens showed a regularly scaling zone without necrosis in 7 cases, and in one case a partial necrosis in the mucosa only was found. CONCLUSION: Cystic artery and cystic duct closure with the new device may be an alternative to the clip. Further trials should evaluate the feasibility and safety of the new device in the clinical setting.

Inducible cyclooxygenase-2 gene expression in the human thyroid epithelial cell line Nthy-ori3-1.

OBJECTIVE: To investigate whether the genes encoding Cyclooxygenase-1 and -2 are expressed in thyroid epithelial cells, in vitro. MATERIALS AND METHODS: COX-1/-2 gene expression was examined in the thyroid epithelial cell line Nthy-ori3-1 using semi-quantitative RT-PCR and Western blot analysis. ELISAs were employed to assess whole cell COX-enzyme activity, PGE2 and IL-6 formation. RESULTS: In response to IL-1beta and TNF-alpha combined cells of the thyroid epithelial cell line Nthy-ori3-1 secreted marked amounts of PGE2 in a time-dependent fashion. This is attributed to increased levels of COX-2 specific mRNA, increased amounts of COX-2 protein and COX enzyme activity in the absence of detectable COX-1 protein. The inhibition of the induced COX enzyme activity by the selective COX-2 inhibitor NS-398 demonstrated the presence of COX-2 pharmacologically. The expression of the COX-2 gene was also accompanied by a marked induction of IL-6 formation, a well described inflammatory response of thyroid epithelial cells. CONCLUSIONS: Our observation presents first evidence that COX-2 gene expression is inducible in thyroid epithelial cells, in vitro, upon stimulation with the pro-inflammatory cytokines IL-1beta and TNF-alpha. This finding may indicate that thyroid epithelial cells could play an inflammatory controlling role perhaps during auto-immune thyroid diseases.