SUMMARYThyroid‐stimulating hormone (TSH) secreting pituitary adenoma is a rare but important cause of thyrotoxicosis. It poses a challenge for both diagnosis and management. We report the case of a young Chinese man presenting with thyrotoxicosis, complicated by congestive heart failure, secondary to a TSH secreting pituitary adenoma. The case illustrates the importance of prompt diagnosis and allows discussion of both medical and surgical management, including the use of a long‐acting somatostatin analogue.
SUMMARYA case of torsion of the wandering spleen with splenic infarction is reported. The medical imaging studies performed with typical findings are described. Case reports have been reviewed. Although rare, torsion of the spleen remains an important differential diagnosis in patients presenting with acute abdominal pain. Early intervention is necessary to reduce the risk of splenic infarction and other complications, and an increased awareness of the condition together with the use of appropriate medical imaging can lead to the correct diagnosis more readily.
Chest pain complicated with electrocardiographic changes is not an uncommon scenario in emergency departments, which should be examined cautiously. We describe a 51-years-old man with a myocardial bridge of coronary artery presenting with simultaneous Mobitz type I atrioventricular block on electrocardiography. Echocardiography excluded valvular abnormality and systolic/diastolic dysfunction. Coronary angiography confirmed the diagnosis of a myocardial bridge at the middle segment of the left anterior descending artery, involving the most dominant septal perforator branch with marked systolic compression. The patient underwent coronary artery bypass grafting surgery and was followed up uneventfully at the outpatient department with medical treatment of diltiazem and clopidogrel. The present case is being reported to highlight that clinicians should be alert to such a congenital abnormality as a potential cause of repeated myocardial infarction and conduction abnormality.
For STEM imaging, the pattern on the detector is a result of interference between elastically scattered wave and the incident wave. By recording the constructive interference and destructive interference with separate detectors, as well as by subtracting the two parts of intensity from each other, one can remove the background intensity as well as nonlinear information. As result, the remaining signal is enhanced phase contrast [1]. A recent experimental demonstration of differential contrast in STEM achieved by matching the detector geometry and the physical phase plates in STEM mode has been reported in [2]. On an aberration‐corrected STEM, an optimized differential phase contrast can be obtained by well designing the PCTF of the objective lens, and detector geometry accordant with the designed phase plate. The integrated spatial frequencies corresponding to positive contrast transfer is equal to those corresponding to negative contrast transfer. This ensures that nonlinear information cancels when the two parts of detector signals subtract each other. Our calculation in Fig. 1 for Cc/Cs‐corrected STEM without damping factors illustrates the advantage of differential contrast compared with the conventional bright‐field imaging in STEM. The differential contrasts of single‐layer graphene are dominantly stronger than the contrasts achieved in STEM‐BF mode equipped with the same corrector. The differential contrast can reach 12, 18 and 26 times of the bright‐field contrast at 20kV, 50kV and 80kV, respectively! This demonstrates that in STEM mode equipped with an aberration corrector and a detector, matching the geometry of the phase plate, phase objects can be imaged with descent contrast. With further improvement of the corrected state of the microscope, our calculation show that phase contrast imaging in STEM offers even more exciting possibilities. When the 5th‐order spherical aberration is corrected, the illumination angle dependent on the largest usable aperture, also increases, resulting in a shallow depth of field. This allows accurate focus at certain thickness of the sample, as shown in Fig. 2. At the 8 th layer of a total 16‐layer (28nm) thick sample of Si, one silicon atom is replaced by a Germanium atom. A focal series through the sample shows that the layer marked by a substituted Ge atom is in focus at △f=‐12Å. As a summary, the method of obtaining differential contrast in an aberration‐corrected STEM can be powerful for investigating weak scattering objects. Under a further improved corrected state of the Cc/Cs corrector, the differential contrast realized with this technique is extremely thickness‐sensitive, and focussing through atomic planes may come into reach.
Thyroid hormones (THs) regulate growth, development, differentiation and metabolic processes by interacting and activating thyroid hormone receptors (TRs). Although much progress has been made in our understanding of the transcriptional regulation of many TR target genes, little is known of the regulation of plasma protein gene expression by TRs. To investigate the role of TRs in plasma protein expression we used human hepatocellular carcinoma cell lines and carried out cDNA microarray analysis. Our results indicate that several plasma proteins including transferrin, prothrombin, angiotensinogen, haptoglobin, alpha-2-HS-glycoprotein alpha and beta chain, complement, lipoproteins and fibrinogen are up-regulated by THs. Furthermore, clusterin, alpha-2-macroglobulin precursor, prothymosin alpha and alpha-fetoprotein were found to be down-regulated by THs.Transferrin, an iron-binding protein expressed in all mammals, and mainly synthesized in the liver, was investigated further. Immunoblot and Northern blot analyses revealed that exposure of HepG2-TRalpha1 sub-lines and HepG2-Neo cells to tri-iodothyronine (T(3)) induced time- and dose-dependent increases in the abundance of transferrin mRNA and protein, with the extent of these effects correlating with the level of expression of TRalpha1. Nuclear run-on experiments indicate that this induction is functioning at the transcriptional level. Moreover, cyclohexamide treatment did not eliminate the induction of transferrin by TH. Thus, our results suggest that the induction of transferrin by TH is direct and may in fact be mediated by an as yet unidentified response element in the promoter region.