Severe Pneumonia Caused by Corynebacterium striatum in Adults,Seoul, South Korea, 2014–2019

We investigated the proportion and characteristics of severe Corynebacterium striatum pneumonia in South Korea during 2014–2019. As part of an ongoing observational study of severe pneumonia among adult patients, we identified 27 severe C. striatum pneumonia cases. Most (70.4%) cases were hospital-acquired, and 51.9% of patients were immunocompromised. C. striatum cases among patients with severe hospital-acquired pneumonia (HAP) increased from 1.0% (2/200) during 2014–2015 to 5.4% (10/185) during 2018–2019, but methicillin-resistant Staphylococcus aureus (MRSA) infections among severe HAP cases decreased from 12.0% to 2.7% during the same timeframe. During 2018–2019, C. striatum was responsible for 13.3% of severe HAP cases from which bacterial pathogens were identified. The 90-day mortality rates were similarly high in the C. striatum and MRSA groups. C. striatum was a major cause of severe HAP and had high mortality rates. This pathogen is emerging as a possible cause for severe pneumonia, especially among immunocompromised patients.     

Pathologic Changes in Wild Birds Infected with Highly Pathogenic Avian Influenza A(H5N8) Viruses,South Korea, 2014

In January 2014, an outbreak of infection with highly pathogenic avian influenza (HPAI) A(H5N8) virus began on a duck farm in South Korea and spread to other poultry farms nearby. During this outbreak, many sick or dead wild birds were found around habitats frequented by migratory birds. To determine the causes of death, we examined 771 wild bird carcasses and identified HPAI A(H5N8) virus in 167. Gross and histologic lesions were observed in pancreas, lung, brain, and kidney of Baikal teals, bean geese, and whooper swans but not mallard ducks. Such lesions are consistent with lethal HPAI A(H5N8) virus infection. However, some HPAI-positive birds had died of gunshot wounds, peritonitis, or agrochemical poisoning rather than virus infection. These findings suggest that susceptibility to HPAI A(H5N8) virus varies among species of migratory birds and that asymptomatic migratory birds could be carriers of this virus.     

Immunohistochemical study for the origin of ductular reaction in chronic liver disease

The appearance of proliferating bile ductular structures, which is called the “atypical ductular reaction” is frequently observed in various chronic liver diseases associated. However, the origin of these increased bile ductules has been a matter of controversy. In this study, we investigated the origin of ductular cells as an aspect of relation between epithelial to mesenchymal transition (EMT) and epithelial members of liver parenchyme, such as hepatocyte and cholangiocyte by immunohistochemical staining of human liver. Thirteen specimens of surgically resected liver with biliary cirrhosis were selected. Three sets of double immunohistochemical stains were done; Hep-Par 1 - cytokeratin 19 (CK19), Hep-Par 1 - α-sm ooth mus cle actin (α-SMA) and CK19 - α-SMA. As a result, we investigated the dual expression of the markers of hepatocyte and cholangiocyte in the same cell; in ductular cell and surrounding hepatocyte. However, there seems to be no dual expression of markers for EMT with epithelial markers. This study suggests a possibility of phenotypic change of mature hepatocyte into cholangiocyte. Future studies will be necessary to determine the role that proliferating cholangiocytes play in the pathogenesis of biliary fibrosis and how cholangiocytes interact with other cell types of the liver such as hepatic stellate cells or Kupffer cells.     

Filling defect in a pulmonary arterial stump on CT after pneumonectomy: radiologic and clinical significance

OBJECTIVE: The objectives of our study were to determine the incidence of filling defects in pulmonary arterial stumps on CT after pneumonectomy and to evaluate their radiologic and clinical significance. MATERIALS AND METHODS: We retrospectively reviewed 401 contrast-enhanced chest CT scans of 147 consecutive patients (male-female ratio, 123:24; mean age, 60 years) who underwent pneumonectomy (right, 60; left, 87) from 1996 to 2002 in our institution. CT findings were analyzed for the presence or absence of a filling defect in the vascular stump and its size, shape, and interval change on follow-up CT. CT findings were also evaluated for the length of the vascular stump and the presence of embolism in the contralateral pulmonary arteries, pneumonia, bronchopleural fistula, and bronchiolitis obliterans with organizing pneumonia. Intrathoracic or stump recurrence was also assessed in patients with lung cancer. The medical records of lung cancer patients were reviewed for the cause of pneumonectomy and stage and cell type of cancer at surgery. Statistical tests were performed to determine the relationship between the filling defect and other radiologic and clinical findings. RESULTS: A filling defect in the vascular stump was seen on CT scans of 18 patients after pneumonectomy (12%), and all had undergone the surgery for lung cancer. It was more frequently found in the right-sided stump (23.3%) than in the left-sided stump (4.6%) (p = 0.001). The vascular stump was longer in patients with a filling defect (37.2 +/- 6.8 [1 SD] mm) than those without this finding (25.0 +/- 12.5 mm) (p < 0.001). Other radiologic and clinical findings were not significantly related to the presence of the filling defect in the vascular stump. CONCLUSION: A filling defect in the pulmonary arterial stump seen on CT after pneumonectomy is thought to be an in situ thrombus caused by stasis of blood flow and is not related to pulmonary embolism, tumor recurrence, or other complications after pneumonectomy.     

Pulmonary parenchymal involvement of low-grade lymphoproliferative disorders

Lymphoid tissue is a normal component of the lung. The various lymphoproliferative diseases affect the lung parenchyma. The purpose of this article is to classify various lymphoproliferative diseases and to understand their computed tomography features of pulmonary involvement. The examples include follicular bronchiolitis, lymphocytic interstitial pneumonia, plasma cell granuloma, Castleman disease, lymphomatoid granulomatosis, and mucosa-associated lymphoid tissue lymphoma. Pathologic correlation is helpful for understanding imaging findings and their pathophysiology.     

Liquid-Crystal Display Monitors and Cathode-Ray Tube Monitors: A Comparison of Observer Performance in the Detection of Small Solitary Pulmonary Nodules

Objective

To compare observer performance using liquid-crystal display (LCD) and cathode-ray tube (CRT) monitors in the interpretation of soft-copy chest radiographs for the detection of small solitary pulmonary nodules.

Materials and Methods

By reviewing our Medical Center''s radiologic information system, the eight radiologists participating in this study (three board-certified and five resident) retrospectively collected 40 chest radiographs showing a solitary noncalcified pulmonary nodule approximately 1 cm in diameter, and 40 normal chest radiographs. All were obtained using a storage-phosphor system, and CT scans of the same patients served as the gold standard for the presence of a pulmonary nodule. Digital images were displayed on both high-resolution LCD and CRT monitors. The readers were requested to rank each image using a five-point scale (1 = definitely negative, 3 = equivocal or indeterminate, 5 = definitely positive), and the data were interpreted using receiver operating characteristic (ROC) analysis.

Results

The mean area under the ROC curve was 0.8901±0.0259 for the LCD session, and 0.8716±0.0266 for the CRT session (p > 0.05). The reading time for the LCD session was not significantly different from that for the CRT session (37.12 and 41.46 minutes, respectively; p = 0.889).

Conclusion

For detecting small solitary pulmonary nodules, an LCD monitor and a CRT monitor are comparable.     

The function, composition, and particle size of high-density lipoprotein were severely impaired in an oliguric phase of hemorrhagic fever with renal syndrome patients

BACKGROUND: Patients suffering from hemorrhagic fever with renal syndrome (HFRS) often showed strikingly reduced high-density lipoprotein (HDL)-cholesterol levels during the oliguric phase, indicating severe alterations in lipoprotein metabolism. OBJECTIVE: To compare changes in the functions and composition of HDL, lipoprotein metabolism parameters were analyzed in the sera of HFRS patients in the oliguric phase and after recovery. METHODS: The serum cholesterol, triglyceride (TG), and lipoprotein/apolipoprotein profiles of HFRS patients in the oliguric and recovery phases were compared with those of normal reference sera. The activities of HDL-associated enzymes, lecithin:cholesterol acyltransferase (LCAT), and paraoxonase (PON) were also assessed. RESULTS: In the oliguric phase, serum cholesterol was substantially decreased and serum TG was increased. As observed by electron microscopy, the sizes of the HDL particles from the HFRS patients were smaller than those seen in the reference sera, with more heterogeneous distribution. Serum amyloid A (SAA) and apolipoprotein (apo) C-III were overexpressed in the oliguric phase, particularly in the HDL fraction. However, in immunodetection, the levels of apoA-I in the HDL(2) and HDL(3) of the HFRS patients were lower than those of the reference HDL. Serum LCAT and PON activities were reduced significantly in the oliguric phase, which is associated with a reduction in HDL-cholesterol levels and HDL particle size. CONCLUSION: Overexpression of both apoC-III and apoSAA in HDL and attenuated serum LCAT and PON activity were observed during the oliguric phase in HFRS patients. These results demonstrate that structural, functional, and compositional changes of HDL occurred to a substantial degree in the oliguric phase.