Prediction and observation of an antiferromagnetic topological insulator.

Magnetic topological insulators are narrow-gap semiconductor materials that combine non-trivial band topology and magnetic order1. Unlike their nonmagnetic counterparts, magnetic topological insulators may have some of the surfaces gapped, which enables a number of exotic phenomena that have potential applications in spintronics1, such as the quantum anomalous Hall effect2 and chiral Majorana fermions3. So far, magnetic topological insulators have only been created by means of doping nonmagnetic topological insulators with 3d transition-metal elements; however, such an approach leads to strongly inhomogeneous magnetic4 and electronic5 properties of these materials, restricting the observation of important effects to very low temperatures2,3. An intrinsic magnetic topological insulator-a stoichiometric well ordered magnetic compound-could be an ideal solution to these problems, but no such material has been observed so far. Here we predict by ab initio calculations and further confirm using various experimental techniques the realization of an antiferromagnetic topological insulator in the layered van der Waals compound MnBi2Te4. The antiferromagnetic ordering  that MnBi2Te4  shows makes it invariant with respect to the combination of the time-reversal and primitive-lattice translation symmetries, giving rise to a ℤ2 topological classification; ℤ2 = 1 for MnBi2Te4, confirming its topologically nontrivial nature. Our experiments indicate that the symmetry-breaking (0001) surface of MnBi2Te4 exhibits a large bandgap in the topological surface state. We expect this property to eventually enable the observation of a number of fundamental phenomena, among them quantized magnetoelectric coupling6-8 and axion electrodynamics9,10. Other exotic phenomena could become accessible at much higher temperatures than those reached so far, such as the quantum anomalous Hall effect2 and chiral Majorana fermions3.

[Breast pain and fever in a 46-year-old immunosuppressed patient with breast implants]. / Schmerzen im Bereich der Mamma und Fieber bei einer 46­Jährigen mit Immunsuppression und Mammaaugmentation.

A 46-year-old immunosuppressed patient presented with a breast implant-associated infection 10 years after breast augmentation in Southeast Asia. No pathogen was identified in the initial conventional microbiological workup. Subsequently, infection with Mycobacterium abscessus-a nontuberculous mycobacteria-was diagnosed using a special culture technique. Increased rates of such infections are reported after cosmetic surgery in foreign countries, presumably due to inoculation with these ubiquitous pathogens. This case highlights the fact that the differential diagnosis and thus the microbiological workup should be extended in cases without initial pathogen detection.

[Detection of cardial and extracardial right-to-left shunts in young stroke patients]. / Detektion kardialer und extrakardialer Rechts-links-Shunts bei jüngeren Schlaganfallpatienten.

BACKGROUND: The aim of this study was to determine the frequency of extracardial and particularly pulmonal right-to-left-shunts (RLS) in patients with acute cerebral ischemia of unknown origin. PATIENTS AND METHODS: We investigated 52 patients under 60 years of age with cerebral ischemic stroke of unknown origin using transesophageal echocardiography (TEE) with special attention to the late phase of ultrasound contrast medium in the left atrium. Additionally we performed contrast transcranial doppler sonography (TCD). RESULTS: In the TEE, 25 patients (48%) showed cardial RLS. In seven patients with normal TEE (13.5%) we found evidence of RLS with contrast TCD (spontaneous RLS n=4, RLS after valsalva n=3). In none of these seven patients did we find late-phase contrast in the left atrium. CONCLUSION: The constellation of RLS detection in contrast TCD but not in TEE was frequently found. Particularly in spontaneous RLS, this constellation raises the suspicion of a pulmonary shunt. However our extended TEE protocol did not give additional evidence for a pulmonary location of the shunt.

Pharmacokinetics and pharmacodynamic effects of oral GLP-1 and PYY3-36: a proof-of-concept study in healthy subjects.

This proof-of-concept study was performed in order to establish the pharmacokinetics and pharmacodynamics of increasing oral doses of the satiety peptides glucagon-like peptide-1 (GLP-1) and peptide YY3-36 (PYY3-36). Six healthy male subjects were given oral doses of either a placebo or GLP-1 in a dose-escalating schedule (doses of 0.5, 1.0, 2.0, and 4.0 mg). Next, another group of six healthy male subjects were given oral doses of either a placebo or PYY3-36 in the same pattern of escalating doses (doses of 0.25, 0.5, 1.0, 2.0, and 4.0 mg). In healthy male volunteers, (i) oral administration of either of the peptides induced a rapid and dose-dependent increase in plasma drug concentrations; (ii) oral administration of GLP-1 induced a potent effect on insulin release; and (iii) both peptides suppressed ghrelin secretion. In conclusion, this study showed, for the first time, that satiety peptides such as GLP-1 and PYY3-36 can be orally delivered safely and effectively in humans.

[Intracranial bleeding in acquired hemophilia]. / Intrakranielle Blutung bei erworbener Hemmkörperhämophilie.

Acquired hemophilia is a rare complication in autoimmune disorders and malignancies. It can result in bleedings into skin and muscle, whereas intracranial hemorrhage in adults has so far not been described. We report a patient with acute intracerebral hemorrhage due to acquired hemophilia with factor VIII inhibition. The patient was treated with recombinant factor VIIa and open hematoma evacuation followed by administration of cortisone and cyclophosphamide. After good initial recovery, intracerebral rebleeding occurred and the patient died from brainstem compression.

[The German Quality Management System for Outpatient Care (Q-M-A) Checklist--an instrument for assessing quality management systems in outpatient care]. / Die Checkliste Q-M-A--ein Instrument zur Bewertung von Qualitätsmanagementsystemen in der ambulanten Versorgung.

Quality management systems had originally been designed for industrial purposes and were hardly applicable for small enterprises, there have been adjustments to the two main applications EFQM and ISO enabling utilisation also in ambulatory care. There are also different approaches like the Dutch Visitatiae concept which reflects the needs of GP's and is based on peer exchange. The presented paper gives an overview of existing quality management and certification systems and presents an instrument for evaluation. This checklist was developed by an interdisciplinary expert panel of the Agency for Quality in Medicine and serves as an aid for users and graders of quality management systems with regard to the feasibility of these systems.

Comparison of assays for anti-endomysial and anti-transglutaminase antibodies for diagnosis of pediatric celiac disease.

BACKGROUND: Anti-endomysial antibodies are sensitive and specific markers for celiac disease. This antibody has recently been identified as an antibody to tissue transglutaminase, an enzyme that cross-links and stabilizes extracellular matrix proteins. OBJECTIVES: To evaluate the clinical usefulness of an enzyme-linked immunoassay for anti-transglutaminase antibodies, and to compare the results with those of AEA, the current gold standard serological test for celiac disease. METHODS: Serum samples were collected from 33 patients with biopsy-proven celiac disease and AEA tests were performed. Control samples for anti-transglutaminase were obtained from 155 patients. An ELISA test for immunoglobulin A anti-transglutaminase utilizing guinea pig liver transglutaminase was developed and performed on all sera. Cutoff values for the test were performed using logistic regression and receiver operating curves analysis. RESULTS: An optical density cutoff value of 0.34 was established for the assay. The mean value was 0.18 +/- 0.19 optical density for controls, and 1.65 +/- 1.14 for patients with celiac disease (P < 0.001). Sensitivity and specificity of the assay were both 90%, while AEA had a sensitivity and specificity of 100% and 94%, respectively. CONCLUSIONS: A tissue transglutaminase-based ELISA test is both sensitive and specific for detection of celiac disease.

Signs and symptoms of the myofascial pain syndrome: a national survey of pain management providers.

OBJECTIVE: The goal of this study was to assess clinical consensus regarding whether myofascial pain syndrome (MPS) is a legitimate and distinct diagnosis as well as the signs and symptoms characterizing MPS. DESIGN: A standardized mailed survey with return postage provided. SUBJECTS: A total of 1,663 American Pain Society members in medically related disciplines listed in the 1996/1997 directory. OUTCOME MEASURES: A standardized survey assessing clinical opinion regarding whether MPS is a legitimate diagnosis, whether MPS is a clinical entity distinct from fibromyalgia, and the signs and symptoms believed to be "essential to," "associated with," or "irrelevant to" to the diagnosis of MPS. RESULTS: Of the 403 surveys returned, 88.5% respondents reported that MPS was a legitimate diagnosis, with 81% describing MPS as distinct from fibromyalgia. The only signs and symptoms described as essential to the diagnosis of MPS by greater than 50% of the sample were regional location, presence of trigger points, and a normal neurologic examination. Regarding the signs and symptoms considered to be essential or associated with MPS, more than 80% of respondents agreed on regional location, trigger points, normal neurologic examination, reduced pain with local anesthetic or "spray and stretch," taut bands, tender points, palpable nodules, muscle ropiness, decreased range of motion, pain exacerbated by stress, and regional pain described as "dull," "achy," or "deep." Sensory or reflex abnormalities, scar tissue, and most test results were considered to be irrelevant to the diagnosis of MPS by a large proportion of the respondents. CONCLUSIONS: There was general agreement across specialties that MPS is a legitimate diagnosis distinct from fibromyalgia. There was a high level of agreement regarding the signs and symptoms essential or associated with a diagnosis of MPS. Differences across specialties are discussed. This survey provides a first step toward the development of consensus-based diagnostic criteria for MPS, which can then be validated empirically.

Light reflection rheography and clinical course of patients with advanced venous disease before and after endoscopic subfascial division of perforating veins.

BACKGROUND: Endoscopic subfascial division of perforating veins (ESDP) has been shown to cause fewer surgical complications than classic techniques. OBJECTIVE: To evaluate the efficacy of ESDP based on patients' symptoms, rheographic data, and ulcer healing. METHODS: Thirty-two subsequent patients underwent 40 ESDP procedures. Fifteen limbs presented with a postthrombotic syndrome (PTS), and 16 cases had an active venous ulcer. Data were recorded before and 2 months after ESDP. Stripping or high ligation procedures had been previously performed. RESULTS: The symptoms of pain and edema improved in 80% (PTS) and 74% (venous ulcer) of patients. Only one case did not show improvement of either pain or edema. Fifty-eight percent of patients showed hemodynamic improvement by light reflection rheography (LRR), while 32% did not change and 10% of patients had a worsened LRR after ESDP. The LRR refilling times increased by a median factor of 1.69, reaching at least 20 seconds in nine of 40 limbs. Venous ulcers that had been active for a median of 12 years (range, 0.5-21) healed in nine of 16 cases within 14-50 days (median, 21 days). CONCLUSION: ESDP reduces disease-related symptoms, improves hemodynamics in almost 60%, and facilitates healing of long lasting venous ulcers.

Occupational protein contact dermatitis caused by meat and fish.

BACKGROUND: Protein contact dermatitis is a form of contact dermatitis possibly triggered by proteinaceous allergens. MATERIALS AND METHODS: We report two patients with a history of erythematous and urticarial skin reactions followed by transformation into prolonged papular symptoms upon contact with proteinaceous material. RESULTS: The symptoms reported by the patients were reproducible by skin testing with meat (cow) and fish (salmon). Both patients experienced extracutaneous manifestations after ingestion of meat and fish, as proven by oral challenge. Specific immunoglobulin E (IgE) antibodies were detected in the patients' blood. CONCLUSIONS: Both cases meet all major criteria of protein contact dermatitis, suggesting IgE-mediated immediate-type hypersensitivity with late-phase cutaneous reactions.

MRI in sporadic Creutzfeldt-Jakob disease: correlation with clinical and neuropathological data.

To ascertain whether increased grey matter signal intensity on T2-weighted images in patients with sporadic Creutzfeldt-Jakob disease (CJD) corresponds to the stage and severity of this disease, we correlated MRI findings in four of our own and previously reported patients with sporadic CJD with the clinical variants, neuropathological changes at autopsy, duration of the disease and survival time after MRI examination. Of 15 patients with the extrapyramidal type of CJD, 10 showed increased signal in the basal ganglia on T2-weighted images. One of seven patients with the Heidenhain variant had increased signal in the occipital cortex. Patients without increased grey matter signal intensity had a longer overall duration of CJD (P = 0.035). Although the interval between onset of neurological symptoms and MRI was not different, patients without increased grey matter signal also survived longer after MRI examination (P = 0.022).

High ligation and stripping of the long saphenous vein using the tumescent technique for local anesthesia.

BACKGROUND: Advantages of tumescent local anesthesia (TLA) have been described for use in ambulatory phlebectomy removing large varicose side branches. OBJECTIVE: To evaluate the TLA method for high ligation and stripping of the long saphenous vein with or without administration of intravenous sedatives. METHODS: Forty-nine patients underwent 58 phlebosurgical procedures, including 41 ligations and strippings of the long saphenous vein. They were kept in the hospital for 24 hours after surgery to record potential complications and demand for medical assistance. RESULTS: The surgical procedures were easily performed under TLA without major complications. Minor complications were mild hematoma (n = 2) and temporary inguinal seroma (n = 1). Forty-one percent of the patients required additional i.v. sedation and analgesia perioperatively. Postsurgical guidance by a physician was necessary only in patients on full-dose heparin. CONCLUSION: The tumescent technique for local anesthesia allows high ligation and stripping of the long saphenous vein even in both legs in one session, however, frequently with additional i.v. medication.

[Craniocervical dissections: study strategies in MR imaging and MR angiography]. / Kraniozervikale Dissektionen: Untersuchungsstrategien in der MR-Tomographie und MR-Angiographie.

PURPOSE: To define the diagnostic efficacy of MR imaging, "time of flight" (TOF) and phase contrast (PC) MR angiography in craniocervical arterial dissections. MATERIAL AND METHODS: The MR examinations of 16 patients with proven arterial dissections (n = 20) were retrospectively analysed by three independent readers. The MR protocol included T1w spin echo sequences with and without fat saturation (SPIR), T2w-turbo-spin echo, 2D- and 3D-TOF- and 3D-PC-MRA. The study was undertaken to assess the diagnostic sensitivity of each technique in detecting typical pathological features. RESULTS: The overall sensitivity was best in 3D-PC-MRA; reaching 88% of all possible points. Intramural haematoma could be easily detected with T1W spin echo with fat saturation (100%). Intimal flap and lumen narrowing was best defined with 3D-TOF-MRA in 86% resp. 96% and 3D-PC-MRA in 69% resp. 97%. 3D-PC-MRA was superior to all other sequences in 5 cases of aneurysmal dissection (100%). CONCLUSIONS: An accurate evaluation of craniocervical arterial dissections should rely on a combined protocol including T1w spin echo with fat saturation and an axial 3D-MR angiography (if possible 3D-phase contrast MRA).

[Endovascular balloon occlusion test of the internal carotid artery with increased hemodynamic monitoring for determination of circulatory reserve before planned carotid occlusion]. / Endovaskulärer Ballonokklusionstest der A. carotis interna mit erweitertem hämodynamischen Monitoring zur Bestimmung der Durchblutungsreserve vor geplantem Karotisverschluss.

PURPOSE: To evaluate stroke risk assessment of balloon test occlusion of the internal carotid artery (ICA) with enlarged haemodynamic monitoring prior to permanent ICA occlusion. MATERIAL AND METHODS: 24 patients with cervical metastasis (n = 18), cavernous meningiomas (n = 3) or inoperable cavernous aneurysms (n = 3) were examined. The test occlusion was monitored by EEG, neurological examinations and transcranial Doppler sonography of the ipsilateral middle cerebral artery with evaluation of the cerebrovascular reserve capacity. Additionally 99mTc-HMPAO-SPECT imaging was added showing the perfusion during test occlusion. RESULTS: In one (4%) patient the test occlusion had to be interrupted previously due to an acute neurological deficit. This patient and two (8%) patients with highly pathological test results in SPECT and TCD were excluded from permanent carotid occlusion. In 6 (25%) patients quantitative TCD monitoring could improve the stroke risk assessment by differentiating the patients in a low and high risk group. 6 (25%) patients were definitely occluded without haemodynamic complications, but two patients suffered from embolic infarctions which cannot be predicted by this procedure. CONCLUSIONS: The multimodal balloon test occlusion with enlarged haemodynamic monitoring allows haemodynamic stroke risk assessment prior to permanent occlusion of the ICA.

Expression of opioid receptors during heart ontogeny in normotensive and hypertensive rats.

BACKGROUND: The opioidergic systems are involved in modulating nociceptive stimuli. In addition, the recent results suggest that endogenous and exogenous opioids could play a role in the modulation of blood pressure and cardiac functions. However, little is known regarding the expression and role of opioid-binding sites in the heart. The decreased sensitivity to noxious stimuli in hypertensive rats raises the possibility of different developmental pattern expression of opioid-binding sites in normotensive versus hypertensive rats. METHODS AND RESULTS: Opioid receptor expression in hearts from hypertensive and normotensive rats was studied during heart development by binding assays. From P1 until P90, the development of the heart in the two rat strains was accompanied by a gradual increase in the density of kappa-opioid receptors. Hearts from hypertensive rats expressed significantly higher levels of kappa receptors compared with those of normotensive rats. At ages older than P7, mu-opioid receptors could not be detected in hearts of both strains, whereas delta-opioid-binding sites gradually increased until reaching adult levels. Seven-day-old cardiomyocyte cultures of both rat strains expressed similar densities of delta or kappa receptors to those observed in hearts from 7-day-old neonates. The mu-binding sites were not detected in cardiomyocytes cultures. Similar to the in vivo state, cultured myocytes from hypertensive rats had significantly higher levels of kappa-binding sites (1.5 fold) compared with those of normotensive rats. The kappa sites are pertussis toxin sensitive, and the state of coupling of the receptor to G protein is similar for the two rat strains. CONCLUSION: The role of opioid-binding sites in the heart is not completely clear. Hypertensive rats are known to be less sensitive to noxious stimuli compared with normotensive rats. It is controversial whether the site if application of noxious stimuli plays an important role in the sensitivity to pain in hypertensive rats. We suggest that the opioidergic system could play a role in the modulation of blood pressure in addition to its known effect on nociception.

Hyperinsulinaemia increases blood pressure in genetically predisposed spontaneously hypertensive rats but not in normotensive Wistar-Kyoto rats.

BACKGROUND: There is controversy in the literature concerning the effect of short-term insulin administration on blood pressure in different experimental situations, because in some experiments this association is clear, whereas in others it is nonexistent. OBJECTIVE: To investigate whether there is a difference in the effect of exogenous insulin administration on the blood pressure of normotensive Wistar-Kyoto (WKY) rats and hypertensive spontaneously hypertensive rats (SHR). METHODS: Hyperinsulinaemia was induced in normotensive WKY rats and in hypertensive SHR by the administration of long-acting insulin (insulin retard 0.4 U/kg body weight per day in one group and 0.8 U/kg body weight per day in another group) once a day, intraperitoneally, for 3 weeks. All of the rats drank a 10% sucrose solution, to prevent hypoglycaemia in those receiving insulin. RESULTS. Baseline serum levels were significantly higher in the SHR groups than in the WKY rat groups. At the end of the experiment, after 3 weeks' insulin therapy, systolic blood pressure measured by the tail-cuff method showed a significant increase in the SHR, but not in the WKY rats, possibly because of the genetic predisposition of the SHR to increase their blood pressure. The increase was similar in the SHR given 0.4 U/kg body weight per day insulin retard to that in those given 0.8 U/kg per day. CONCLUSIONS: Exogenous insulin increased systolic blood pressure in the SHR but not in the WKY rats. The rise was similar in rats receiving either 0.4 or 0.8 U/kg body weight per day insulin retard.

Insulin induces medial hypertrophy of myocardial arterioles in rats.

To investigate the effect of hyperinsulinemia on arteriolar hypertrophy, myocardial hypertrophy, and blood pressure, we administered insulin intraperitoneally to SHR and WKY rats for 3 consecutive weeks. To prevent hypoglycemia, the drinking water contained 10% sugar, and to accentuate the blood pressure, their chow contained 8% table salt. Blood pressure was measured by the tail-cuff method. Heart weights were factored with body weights. Arterioles of approximately 100 microns in diameter were examined at the end of the experiment and the vascular wall thickness was factored with the lumen diameter. At the end of 3 weeks, blood pressure rose in the SHR but not in the WKY rats. The heart weights in the WKY normotensive rats did not increase, whereas in the SHR they did. Furthermore, there was a significant rise in vessel wall thickness in the rats that received insulin, whether there was a rise in blood pressure or not and whether they had an increase in heart weight or not. There was a similar rise in blood glucose in all the groups, with slightly more accentuated rise in the SHR that received insulin. Nevertheless the increase in vascular wall thickness occurred only in the groups which received insulin. This seems to preclude the importance of hyperglycemia per se as the causative agent for the increase in vascular wall thickness in this study. The increase was in the form of medial hypertrophy without any sign of atherosclerosis. It seems, therefore, that hyperinsulinemia is associated with hypertrophy of the media of arterioles regardless of the increase in heart weight or the rise in blood pressure.

Heritable nail diseases.

Heritable nail diseases are associated with a great variety of inherited diseases and syndromes. Well over 60 HEDs and numerous other inherited nail abnormalities are known to exist. A classification system of these disorders, as well as the specific nail change found in each, has been presented. Table 1 has been included to correlate many of the nail disorders with their corresponding inherited disease or syndrome. Clinically, inherited nail diseases may appear to be of questionable importance. In cases of primary presentation or poor historical background, however, these subtle nail changes may prove useful in arriving at or substantiating a diagnosis.