When hydrogen bonding overcomes Coulomb repulsion: from kinetic to thermodynamic stability of cationic dimers.

Quantum chemical calculations have been employed to study the kinetic and thermodynamic stability of hydroxy-functionalized 1-(3-hydroxyalkyl)pyridinium cationic dimers. For [Py-(CH2)n-OH+]2 structures with n = 2-17 we have calculated the robust local minima with clear dissociation barriers preventing their "Coulomb explosion" into separated cations. For n = 15 hydrogen bonding and dispersion forces fully compensate for the repulsive Coulomb forces between the cations allowing for the quantification of the pure hydrogen bond in the order of 20 kJ mol-1. The increasing kinetic stability even turns to thermodynamic stability with further elongated hydroxyalkyl chains. Now, quantum-type short-range attraction wins over classical long-range electrostatic repulsion resulting in negative binding energies and providing the first thermodynamically stable cationic dimers. The electronic, structural and spectroscopic signatures of the cationic dimers could be correlated to NBO parameters, supporting the existence of anti-electrostatic hydrogen bonds (AEHB) as recently suggested by Weinhold. In principle, these pure cationic dimers should be detectable in gas-phase experiments at low temperatures without the need of mediating molecules or counteranions.

Early detection of lung cancer: a statement from an expert panel of the Swiss university hospitals on lung cancer screening.

The discussion about setting up a program for lung cancer screening was launched with the publication of the results of the National Lung Screening Trial, which suggested reduced mortality in high-risk subjects undergoing CT screening. However, important questions about the benefit-harm balance and the details of a screening program and its cost-effectiveness remain unanswered. A panel of specialists in chest radiology, respiratory medicine, epidemiology, and thoracic surgery representing all Swiss university hospitals prepared this joint statement following several meetings. The panel argues that premature and uncontrolled introduction of a lung cancer screening program may cause substantial harm that may remain undetected without rigorous quality control. This position paper focuses on the requirements of running such a program with the objective of harmonizing efforts across the involved specialties and institutions and defining quality standards. The underlying statement includes information on current evidence for a reduction in mortality with lung cancer screening and the potential epidemiologic implications of such a program in Switzerland. Furthermore, requirements for lung cancer screening centers are defined, and recommendations for both the CT technique and the algorithm for lung nodule assessment are provided. In addition, related issues such as patient management, registry, and funding are addressed. Based on the current state of the knowledge, the panel concludes that lung cancer screening in Switzerland should be undertaken exclusively within a national observational study in order to provide answers to several critical questions before considering broad population-based screening for lung cancer.

Computed tomography for pulmonary embolism: assessment of a 1-year cohort and estimated cancer risk associated with diagnostic irradiation.

BACKGROUND: The principal concern of any radiation exposure in computed tomography (CT) is the induction of stochastic risks of developing a radiation-induced cancer. The results given in this manuscript will allow to (re-)calculate yield of chest CT. PURPOSE: To demonstrate a method to evaluate the lifetime attributable risk (LAR) of cancer incidence/mortality due to a single diagnostic investigation in a 1-year cohort of consecutive chest CT for suspected pulmonary embolism (PE). MATERIAL AND METHODS: A 1-year cohort of consecutive chest CT for suspected PE using a standard scan protocol was analyzed retrospectively (691 patients, 352 men, 339 women). Normalized patient-specific estimations of the radiation doses received by individual organs were correlated with age- and sex-specific mean predicted cancer incidence and age- and sex-specific predicted cancer mortality based on the BEIR VII results. Additional correlation was provided for natural occurring risks. RESULTS: LAR of cancer incidence/mortality following one chest CT was calculated for cancer of the stomach, colon, liver, lung, breast, uterus, ovaries, bladder, thyroid, and for leukemia. LAR remains very low for all age and sex categories, being highest for cancer of the lungs and breasts in 20-year-old women (0.61% and 0.4%, respectively). Summation of all cancer sites analyzed raised the cumulative relative LAR up to 2.76% in 20-year-old women. CONCLUSION: Using the method presented in this work, LAR of cancer incidence and cancer mortality for a single chest CT for PE seems very low for all age groups and both sexes, but being highest for young patients. Hence the risk for radiation-induced organ cancers must be outweighed with the potential benefit or a treatment and the potential risks of a missed and therefore untreated PE.

[Inicidental finding: patient with cervical spine trauma]. / Zufallsbefund bei Einem Patienten mit Zervikalem Trauma.

An ossification of the posterior longitudinal ligament, often presenting asymptomatically, can cause a symptomatic myelopathy after trauma. Keeping this entity in mind in daily clinical routine will help in making the correct diagnosis and in administering the corresponding therapy.

Detection of urolithiasis using low-dose CT--a noise simulation study.

How does an acquisition at reduced doses using automatic tube current modulation techniques compare to the normal standard dose CT? Does it affect the sensitivity for detection of calcifications? CT raw data of 54 patients with suspected urolithiasis acquired with automatic tube current modulation techniques were used for image noise simulations with 100%, 50% and 25% dose simulated. Data were analyzed by independent readers with regard to the presence of urolithiasis, stone location, size, density and differential diagnoses. The mean effective dose per standard examination/50%/25% simulation was 7.3 mSv/3.8 mSv/1.9 mSv. Sensitivities/specificities for detection of urolithiasis were calculated for all dose simulations and resulted in 0.94/0.98 in the 50% dose level group and 0.82/0.97 in the 25% dose level group. Low-dose CT with tube current modulation can be used as a standard procedure for the evaluation of patients with suspected acute renal colic.

[Confusion, gait ataxia and ophthalmoplegia in a patient with chronic alcohol consumption]. / Kognitive Störungen, Gangataxie und Blickparese bei einem Patienten mit chronischem Alkoholabusus.

Wernicke encephalopathy is a neurological disorder, often caused by a lack of thiamine. Immediate diagnosis and therapy are important to prevent significant morbidity and mortality. Based on a clinical case radiologic imaging features on MRI are demonstrated.

[Alcoholism and possible consequences for the central nerval system - pontine and extrapontine myelinolysis]. / Chronischer Alkoholkonsum und Elektrolytdysbalancen - Mögliche Folgen für das ZNS.

The central pontine and extrapontine myelinolysis is an important entity in the neurology disorders in the context with alcohol abuse. Though often first based on clinical characteristics, the diagnosis can be often supported with radiologic imaging.

Transthoracic sonography for the detection of pulmonary embolism--a meta-analysis.

PURPOSE: Radiation protection is a major issue since the implementation of MSCT technology and its widespread indication for the detection of various diseases. In a European-wide trial (SECT) meta-analyses of imaging alternatives to CT have been initiated. This paper focuses on the diagnostic performance of transthoracic ultrasound (TUS) for the diagnosis of pulmonary embolism (PE) (5 studies, 652 patients). MATERIALS AND METHODS: Medical literature (from 1990 to 2006) in PubMed and EMBASE databases was searched for articles on studies that used TUS as diagnostic tests for PE. Studies were included if they reported the positive and negative rates of PE diagnoses from TUS compared with the rates of PE in CT, MRI or a combination of diagnostic tests. Two readers assessed the quality of the studies. RESULTS: Pooled sensitivity and specificity of TUS for PE were 80 % (95 % CI: 75 %, 83 %) and 93 % (95 % CI: 89 %, 96 %), respectively. CONCLUSION: In the time of MSCT, TUS is an imaging modality that is no longer part of recent diagnostic algorithms for the diagnosis of PE. Considering the increasing number of requested CT examinations and therefore increasing collective radiation dose, this meta-analysis shows that TUS is a diagnostic alternative for special clinical settings in the work-up of suspected PE that seems to have fallen into oblivion.

[Surgical strategies in the treatment of acute diverticular disease--a retrospective analysis of surgical patients at the hospital "Städtisches Klinikum Brandenburg an der Havel"]. / Chirurgische Therapieoptionen bei akuter Sigmadivertikulitis--eine retrospektive Fallanalyse des chirurgischen Krankengutes am Städtischen Klinikum Brandenburg an der Havel.

BACKGROUND: Depending on the degree of severity of acute diverticular disease, operative therapy is performed as an emergency, urgent or elective resection. A challenge is posed not only by the decision on whether to opt for conservative therapy or speedy resection, but also, when resection is indicated, by choosing the most suitable procedure (primary anastomosis or discontinuity resection). The frequency of use of the various therapeutic concepts and their success rates were studied in our clinic. METHODS: All cases of acute sigmoid diverticulitis (108) surgically treated in the Klinikum Brandenburg from 2003 to 2005 were analysed retrospectively. RESULTS: 17 patients (15.7 %) underwent emergency resection with primary anastomosis (8) (of these, 4 were with additional protective stoma) or Hartmann procedure (9). 17 patients (15.7 %) required urgent laparotomy, 11 needed primary anastomosis (protective stoma in 8 patients) and the Hartmann procedure was performed in 3 patients. In 2 patients the laparotomy was limited to colostomy with drainage without resection because of the high cardiac risk under anaesthesia. Of 49 patients (45.4 %), 25 underwent elective resection via laparotomy, and 24 via laparoscopy, with protective stomas in 4 and 3 patients, respectively. 25 patients (23.1 %) were treated conservatively: in 8 cases a later resection was recommended. Revision was necessary in 10 cases due to anastomosis dehiscence (4), bleeding (1), stoma necrosis (2), ileus (1), wound dehiscence (1) or for programmed lavage after free perforation with faecal peritonitis (2). 3 multimorbid patients died after emergency laparotomy. CONCLUSION: A concept of staged treatment can reduce the number of emergency laparotomies; it provides for early focus removal in cases which cannot be managed adequately with conservative treatment and aims for the largest possible number of elective resections.

[Kissing osteochondroma of the lower limb]. / Kissing Osteochondrom--wenn Knochen sich küssen.

As definition, a "kissing" osteochondroma is a typical new bony formation with erosion on the adjacent paired bone, provoked by pressure of the outgrowth. Further diagnostics for incidentally diagnosed solitary osteochondroma should be performed only in cases where malignant transformation is suspected.

Survival trends among Danish patients undergoing coronary angiography for known or suspected ischaemic heart disease: a population based follow up study, 1992-2000.

OBJECTIVE: To determine, from population based clinical data, changes in the survival of Danish patients examined by coronary angiography for known or suspected ischaemic heart disease (IHD) during the 1990s. DESIGN: Follow up study. SETTING: The departments of cardiology at Rigshospitalet, Copenhagen University Hospital, and Skejby Hospital, Aarhus University Hospital, Denmark. PATIENTS: Patients with IHD (n = 7021) who underwent first time coronary angiography in 1992, 1996, or 2000. MAIN OUTCOMES MEASURES: Three year survival was compared between cohorts and with that of the general population. Cox proportional hazards regression was used to estimate mortality ratios adjusted for differences in patient characteristics. RESULTS: Survival improved substantially--for example, adjusted mortality ratio was 0.69 (95% confidence interval (CI) 0.55 to 0.87) when comparing patients from 2000 with patients from 1992. The absolute standardised survival rates after three years of follow up were 87.1% (95% CI 85.4% to 88.8%), 89.9% (95% CI 88.5% to 91.3%), and 91.2% (95% CI 90.3% to 92.1%) among patients examined in 1992, 1996, and 2000, respectively. The improvement was not explained by the improvement in overall survival in the general population during the study period. CONCLUSIONS: The survival of Danish patients with known or suspected IHD appears to have improved substantially during the 1990s.

Prognostic impact of different regional referral practices for interventional investigation and coronary treatment after exercise testing: a population-based 5-year follow-up study.

OBJECTIVE: To examine the association among different centres' referral practices for coronary angiography (CAG) after exercise testing, with 1- and 5-year outcomes. DESIGN: Observational population-based cohort study. SETTING: All 10 hospitals and six private practising consultants in Aarhus and Ringkjoebing counties (900 000 inhabitants), Denmark. SUBJECTS: All patients who in 1996 had an abnormal bicycle exercise test (n = 736). MEASUREMENTS: Referral for CAG, coronary intervention, cardiovascular and all-cause mortality, and myocardial infarction (MI). RESULTS: As an immediate consequence of the exercise test, 60.7% of subjects were referred for CAG. Based on the centres' fraction of patients referred for CAG, three categories of centres were defined: low (<33%), intermediate (33-66%) and high (>66%). A low compared with a high referral fraction was associated with a similar 5-year mortality and MI ratio [all-cause/cardiovascular mortality rate ratio (RR) = 1.33, 95% confidence interval (CI): 0.45-3.92/RR = 0.62, 95% CI: 0.25-1.57; and MI RR = 0.92, 95% CI: 0.45-1.86]. The same was found for an intermediate compared with a high fraction (all-cause/cardiovascular mortality RR = 0.92, 95% CI: 0.49-1.72/RR = 0.74, 95% CI: 0.42-1.33; and MI RR = 1.07, 95% CI: 0.68-1.70). Estimates were about the same after 1 year of follow-up with no major differences among centres in mortality or MI. CONCLUSIONS: Centres' different referral practices for interventional investigation and treatment were not associated significantly with short-term or long-term mortality or MI among patients with an abnormal exercise test.

Ovarian 'tumor' of the adrenogenital syndrome: the first reported case.

We report the case of a 36-year-old woman with congenital adrenal hyperplasia from 21-hydroxylase deficiency who had been receiving replacement therapy with corticosteroids since birth. At the age of 35 years, she developed abrupt aggravation of her virilizing symptoms and underwent an adrenalectomy and partial left oophorectomy. Persistent virilization and high testosterone levels led to right oophorectomy and completion left oophorectomy 6 months later. Each adnexa contained ovarian or paraovarian soft brown masses that on microscopic examination were identical to the testicular tumor of the adrenogenital syndrome. This represents the first reported case of this pathology (well known in the testis) in the ovary.

Large colorectal adenomas. An approach to pathologic evaluation.

Adenomatous polyps are common neoplastic lesions of the large intestine. The risk of carcinoma increases with polyp size. Small polyps are typically totally embedded for histologic examination, but no standard method for sampling large, grossly benign polyps has been established. We reviewed grossly noninvasive adenomas 2.5 cm or larger to determine the percentage that contained high-grade dysplasia (HGD) and invasive cancer (IC). Based on these findings, we suggest an approach to evaluating large adenomas. Forty-three colon resections met the inclusion criteria (no previous diagnosis of cancer, no gross evidence of invasion, and totally embedded polyp). Twelve (28%) had HGD with 3% (1 of 33 slides) to 100% (4 of 4 slides) containing HGD. Five (12%) had IC with 4% (3 of 72 slides) to 42% (5 of 12 slides) containing IC. All cases with IC had HGD in other slides. Probability studies showed that in the majority of cases, polyps would need to be entirely embedded to have an estimated probability of 95% or more of detecting either HGD or IC. Therefore, grossly noninvasive adenomas should be routinely entirely embedded.

Extended sector biopsy for detection of carcinoma of the prostate.

Purpose: To determine whether an extended sector biopsy of the prostate will increase the detection of prostate cancer, without causing an increase in morbidity. Materials and Methods: A total of 74 men with a mean age of 62.3 years (46-98 years) who either had an elevated PSA or an abnormal digital rectal exam underwent a transrectal ultrasound guided needle biopsy. Beginning on 7/1/98, an extended sector biopsy technique was performed on 74 patients by one urologist (RRB). Each transrectal ultrasound guided needle biopsy included 12 total cores (normal sextant biopsy, 2 in each peripheral zone, and 2 in the transition zone). We retrospectively reviewed the biopsy results for the location of cancer. PSA data and morbidity of the procedures were reviewed. Results: Of 74 total patients, 40 (54.1%) were positive for adenocarcinoma of the prostate. There were 10 positive results detected only in the additional zones. If one looks at the total number of cancers detected (40), then 10/40 (25%) of the cancers detected were found in the additional regions only or in 13.5% of all patients biopsied. Of the 10 patients with sector only prostate cancer, 8 were detected in the peripheral zone, 1 in the transition zone and 1 in both zones. All 10 patients had a Gleason pattern score 3+3=6 or 4+3=7. There were no atypical or PIN cores found in the sector zones only. PSA ranged from 1.2-142 (median 6.0 ng/ml). The median PSA was 6.2 ng/ml in all patients found to have cancer, and 6.0 ng/ml in the cancers detected only in the additional zones. There was 1 (1.4%) complication of urinary retention and fever. Conclusion: Our study suggests that an extensive sector biopsy may increase the detection of prostate cancer by 13.5% over a routine sextant biopsy, without demonstrable serious morbidity.