Thin-section CT findings in Pseudomonas aeruginosa pulmonary infection

OBJECTIVE

The aim of this study was to assess clinical and pulmonary thin-section CT findings in patients with acute Pseudomonas aeruginosa (PA) pulmonary infection.

METHODS

We retrospectively identified 44 patients with acute PA pneumonia who had undergone chest thin-section CT examinations between January 2004 and December 2010. We excluded nine patients with concurrent infections. The final study group comprised 35 patients (21 males, 14 females; age range 30-89 years, mean age 66.9 years) with PA pneumonia. The patients' clinical findings were assessed. Parenchymal abnormalities, enlarged lymph nodes and pleural effusion were evaluated on thin-section CT.

RESULTS

Underlying diseases included malignancy (n=13), a smoking habit (n=11) and cardiac disease (n=8). CT scans of all patients revealed abnormal findings, including ground-glass opacity (n=34), bronchial wall thickening (n=31), consolidation (n=23) and cavities (n=5). Pleural effusion was found in 15 patients.

CONCLUSION

PA pulmonary infection was observed in patients with underlying diseases such as malignancy or a smoking habit. The CT findings in patients with PA consisted mainly of ground-glass attenuation and bronchial wall thickening.

ADVANCES IN KNOWLEDGE

The CT findings consisted mainly of ground-glass attenuation, bronchial wall thickening and cavities. These findings in patients with an underlying disease such as malignancy or a smoking habit may be suggestive of pneumonia caused by PA infection.

Local steroid injection into the artificial ulcer created by endoscopic submucosal dissection for gastric cancer: prevention of gastric deformity

BACKGROUND AND STUDY AIMS

Endoscopic submucosal dissection (ESD) of large gastric lesions results in an extensive artificial ulcer that can lead to marked gastric deformity. The aim of the current study was to evaluate therapeutic efficacy in the prevention of gastric deformity of local triamcinolone acetonide (TCA) injection into the extensive artificial ulcer following ESD.

PATIENTS AND METHODS

A total of 45 patients who were diagnosed with early gastric cancer were enrolled. Patients were randomly assigned by the sealed-envelope randomization method to either local TCA injections (n = 21) or sham-control (n = 20) groups. Two clips were placed at the two maximum outer edges of the artificial ulcer after the lesion had been resected (Day 0). Local TCA injections were performed on postoperative Day 5 and Day 12. The distance between the two clips was measured by endoscopic measuring forceps on Days 5, 12, 30, and 60. Granulation formation and gastric deformity were evaluated by visual analog scale (VAS) on Days 30 and 60.

RESULTS

Local TCA injection did not alter clip-to-clip distance on postoperative Day 60, and formation of flat granulation tissue over the ulcer was followed by regenerative mucosa without any gastric deformity. The sham-control group showed significant shortening of clip-to-clip distance compared with the local steroid-injected group and protruded forms of granulation tissue with mucosal convergence. Histological evaluation revealed prominent growth of neovessels, swelling, and marked increases in endothelial cells in the local steroid-injected group compared with the sham-control group.

CONCLUSIONS

Local steroid injection into the floor of a post-ESD artificial ulcer promotes the formation of granulation tissue at an early stage of the healing process leading to regeneration of gastric mucosa without mucosal convergence or gastric deformity.

MR imaging of IgG4-related disease in the head and neck and brain

SUMMARY

IgG4-related disease is characterized by histologic fibrosis with IgG4-positive plasma cell infiltration. Our study evaluated MR imaging features of IgG4-related disease in the head and neck and brain. Images from 15 patients were retrospectively evaluated for the location, signal intensity, and enhancement patterns of lesions. Lacrimal gland enlargement was observed in 8 cases. Other lesions included orbital pseudotumor in 5, pituitary enlargement in 5, and cranial nerve enlargement in 7; the infraorbital nerve was involved in 4. All lesions were hypointense on T2-weighted images, which is typical for IgG4-related lesions. Multiple sites were involved in the head and neck and brain in 11 patients. The diagnosis of IgG4-related disease should be considered in a patient presenting with T2 hypointense lacrimal gland, pituitary, or cranial nerve enlargement, or a T2 hypointense orbital mass, especially if multiple sites in the head and neck are involved in the presence of elevated serum IgG4.

Turn-back embolization technique for effective transvenous embolization of dural arteriovenous fistulas

For effective transvenous embolization of DAVFs, it is important to place coils at the shunting venous pouch in the initial step of the procedure. When it was difficult to navigate a microcatheter to the shunting venous pouch due to the anatomic relationship of approach routes with targeted pouches, we navigated the microcatheters by a "turn-back technique" within the involved sinuses into the target pouches. Complete occlusion or regression of the DAVF was obtained in all cases.

Diagnostic Ability of Fluid-Attenuated Inversion Recovery MR Imaging to Detect Remnant or Recurrent Meningiomas after Resection

It has been suggested that a difference in signal intensity (SI) between the resection cavity and normal cerebrospinal fluid (CSF) on fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) in partially resected gliomas indicates subsequent or coincident tumor progression. We considered that this would hold true for resected meningiomas as well. Hence, we aimed to assess whether or not such a difference in the SI during the follow-up evaluation helps predict residual or recurrent tumor in resected meningiomas. We evaluated 63 patients with resected meningiomas. The SI within the resection cavity observed on FLAIR images was qualitatively and quantitatively assessed during follow-up. Qualitative analysis comprised visual comparison of the SI in the resection cavity with that of normal CSF by neuroradiologists. The SI in the resection cavity was quantitatively assessed by region of interest (ROI) analysis and normalized against the background noise and CSF SI. Normalized SI recorded during follow-up was compared with that recorded immediately after resection. Tumor progression was defined as a 20% or greater increase in the diameter of the longest residual or recurrent meningioma (Response Evaluation Criteria in Solid Tumors). The sensitivity and specificity of the elevated SI in the resection cavity for indicating residual or recurrent tumor were calculated. Qualitative analysis by FLAIR MRI showed that patients with remnant tumor following surgery had a prolonged SI increase in the resection cavity. Further, SI increase could not always be observed before recurrence, and both SI increase and regrowth remnant/recurrence could be detected in the same MRI examination. In resected meningiomas, leakage of tumor elements into the resection cavity, presumably tumor cells, manifests as an SI increase on FLAIR images and indicates residual or recurrent tumor. However, unlike the previous reports on partially resected gliomas, we concluded that the SI change does not always precede tumor progression or recurrence.

Thoracic duct and cisterna chyli: evaluation with multidetector row CT

OBJECTIVES

The aim of this study was to evaluate the normal anatomy of the thoracic duct and cisterna chyli obtained by axial and multiplanar reformation (MPR) images of 1 mm slice thickness using multidetector row CT (MDCT).

METHODS

We evaluated the ability of MDCT to examine the normal anatomy of the thoracic duct and cisterna chyli. The axial and coronal images of thoracoabdominal MDCT images obtained in 50 patients (20 females and 30 males; mean age, 63.5 years; range, 32-81 years) were reviewed between January and October 2005. We excluded patients with malignant neoplasms, inflammation or vascular diseases (e.g. aortic aneurysm, aortic dissection) and those with a history of thoracoabdominal surgery. The thoracic duct was divided into three anatomical sections: the upper, middle and lower. We evaluated the degree of visualisation and the maximum size of the thoracic duct. We also evaluated the degree of visualisation, maximum size, configuration and location of the cisterna chyli.

RESULTS

Visualisation of the thoracic duct and cisterna chyli was almost 100% on axial and coronal images. The lower section of the thoracic duct was most clearly visualised among the three sections. There was little difference in the maximum size of the thoracic duct among the three sections. The cisterna chyli was most frequently located at the Th12 or L1 level, and the most common type was the "straight thin tube type".

CONCLUSION

Axial and MPR images of 1 mm slice thickness using MDCT can clearly depict the thoracic duct and cisterna chyli.

Thin-section CT findings of patients with acute Streptococcus pneumoniae pneumonia with and without concurrent infection

OBJECTIVES

The aim of this study was to compare the pulmonary thin-section CT findings of patients with acute Streptococcus pneumoniae pneumonia with and without concurrent infection.

METHODS

The study group comprised 86 patients with acute S. pneumoniae pneumonia, 36 patients with S. pneumoniae pneumonia combined with Haemophilus influenzae infection, 26 patients with S. pneumoniae pneumonia combined with Pseudomonas aeruginosa infection and 22 patients with S. pneumoniae pneumonia combined with methicillin-susceptible Staphylococcus aureus (MSSA) infection. We compared the thin-section CT findings among the groups.

RESULTS

Centrilobular nodules and bronchial wall thickening were significantly more frequent in patients with pneumonia caused by concurrent infection (H. influenzae: p<0.001 and p<0.001, P. aeruginosa: p<0.001 and p<0.001, MSSA: p<0.001 and p<0.001, respectively) than in those infected with S. pneumoniae alone. Cavity and bilateral pleural effusions were significantly more frequent in cases of S. pneumoniae pneumonia with concurrent P. aeruginosa infection than in cases of S. pneumoniae pneumonia alone (p<0.001 and p<0.001, respectively) or with concurrent H. influenzae (p<0.05 and p<0.001, respectively) or MSSA infection (p<0.05 and p<0.05, respectively).

CONCLUSIONS

When a patient with S. pneumoniae pneumonia has centrilobular nodules, bronchial wall thickening, cavity or bilateral pleural effusions on CT images, concurrent infection should be considered.

Subdose of fasudil suppresses myocardial fibrosis in aldosterone-salt-treated uninephrectomized rats

Rho/Rho kinase (ROCK) pathway plays an important role in pathological cardiovascular conditions. In the present study, the effect of a subdose of fasudil, a selective ROCK inhibitor, on systemic hypertension and myocardium fibrosis induced by aldosterone was investigated in uninephrectomized Sprague-Dawley rats (SD). Treatment with a fasudil (10 mg/kg x day, s.c.) for 5 weeks decreased the activity of ROCK activity for more than 53% as determined by the expression of phosphorylated Myosin phosphatase target subunit 1 (MYPT1). Although this dose of fasudil did not signifantly prevent hypertension, it remarkably alleviated myocardium hypertrophy and fibrosis. The elevated transcriptional expression of transforming growth factors beta1 (TGF-beta1), atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and collagen I and III was also decreased. These results demonstrated that fasudil can protect the myocardium from injury by aldosterone at a subhypertensive dose.

Meticillin-resistant Staphylococcus aureus and meticillin-susceptible S. aureus pneumonia: comparison of clinical and thin-section CT findings

OBJECTIVES

The purpose of this study was to compare the clinical and thin-section CT findings in patients with meticillin-resistant Staphylococcus aureus (MRSA) and meticillin-susceptible S. aureus (MSSA).

METHODS

We retrospectively identified 201 patients with acute MRSA pneumonia and 164 patients with acute MSSA pneumonia who had undergone chest thin-section CT examinations between January 2004 and March 2009. Patients with concurrent infectious disease were excluded from our study. Consequently, our study group comprised 68 patients with MRSA pneumonia (37 male, 31 female) and 83 patients with MSSA pneumonia (32 male, 51 female). Clinical findings in the patients were assessed. Parenchymal abnormalities, lymph node enlargement and pleural effusion were assessed.

RESULTS

Underlying diseases such as cardiovascular were significantly more frequent in the patients with MRSA pneumonia than in those with MSSA pneumonia. CT findings of centrilobular nodules, centrilobular nodules with a tree-in-bud pattern, and bronchial wall thickening were significantly more frequent in the patients with MSSA pneumonia than those with MRSA pneumonia (p = 0.038, p = 0.007 and p = 0.039, respectively). In the group with MRSA, parenchymal abnormalities were observed to be mainly peripherally distributed and the frequency was significantly higher than in the MSSA group (p = 0.028). Pleural effusion was significantly more frequent in the patients with MRSA pneumonia than those with MSSA pneumonia (p = 0.002).

CONCLUSIONS

Findings from the evaluation of thin-section CT manifestations of pneumonia may be useful to distinguish between patients with acute MRSA pneumonia and those with MSSA pneumonia.

[Evaluation of a new compact prothrombin time-international normalized ratio measurement device in pediatric management]

BACKGROUND

In a pediatric setting, the need for lifetime oral anticoagulation is increasing because of currency of extracardiac total cavo-pulmonary connection (TCPC) and pediatric valve surgery. We evaluated a new compact device "CoaguChek XS" for measuring prothrombin time-internatinal normalized ratio (PT-INR).

METHODS

The international normalized ratio (INR) values obtained from 71 patients (223 samples) by a CoaguChek XS were compared with those obtained by a laboratory-based coagulation analyzer.

RESULTS

The values from the CoaguChek XS had a significant correlation with the laboratory based results. (r2 = 0.92, p < 0.01, regression line y = 1.05 x -0.02).

CONCLUSION

The CoaguChek XS will be useful in pediatric management.

Establishment of pure NOTES procedure using a conventional flexible endoscope: review of six cases of gastric gastrointestinal stromal tumors

An increasing number of reports have recently been published on hybrid natural orifice transluminal endoscopic surgery (NOTES). These reports do not address how to complete an operation with a flexible endoscope alone (pure NOTES), but rather how to combine use of an endoscope and a laparoscope. Surgical procedures using flexible and rigid endoscopes have been developed using different processes and concepts. Recognizing this conceptual difference, we conducted a study to address how to establish a pure NOTES procedure. Six patients with gastric gastrointestinal stromal tumors (GISTs) underwent hybrid NOTES. Each case was retrospectively reviewed to determine the appropriateness of the treatment and the usefulness of the endoscopic submucosal dissection (ESD) method, double-scope method, spaced perforation method, duodenal balloon occlusion method, and loop clip technique. The development of operative procedures that take advantage of the characteristics of flexible endoscopes, even with conventional flexible endoscopic devices and conventional endoscopes alone, may contribute to the realization of pure NOTES.

A case of pneumonitis and encephalitis associated with human herpesvirus 6 (HHV-6) infection after bone marrow transplantation

Human herpesvirus 6 (HHV-6)-associated encephalitis or pneumonitis has been reported in immunocompetent and immunosuppressed individuals. Several MRI studies in patients with HHV-6-associated encephalitis have been presented. However, to the best of our knowledge, no studies describing thin-section CT imaging in patients with HHV-6-associated pneumonitis have been reported. Here we describe a case of HHV-6-associated encephalitis and pneumonitis that developed after bone marrow transplantation. Thin-section CT images of the chest revealed ground-glass attenuation, consolidation and centrilobular nodules in both lungs.

Impact of FOLFOXIRI plus bevacizumab on resectability and survival in patients with initially unresectable liver metastases from colorectal cancer

621

Background: Prognosis in patients with unresectable liver metastases from colorectal cancer is known to be very poor. However, thanks to progress of chemotherapy including molecular-target agents, “conversion” (from unresectable to resectable) has been sometimes seen. The aim of this preliminary study is to clarify the impact of FOLFOXIRI plus bevacizumab (Bev) on conversion and prognosis in patients with initially unresectable liver metastases from colorectal cancer.

Methods: Seven patients with initially unresectable liver metastases from colorectal cancer, who received FOLFOXIRI (LOHP 85mg/m2 D1, CPT-11 150mg/m2 D1, LV 200mg/m2 D1, and 5FU 2,400mg/m2 infusion over 46 hours, D1) plus Bev 5mg/kg bolus every 2 weeks, were included in this study. Resectability, disease-free survival (DFS), and overall survival (OS) after hepatic resection were investigated in detail. In addition, completeness and adverse effects were examined in this regimen.

Results: All 7 patients tolerated the regimen well, and no adverse effect of grade 3-4 was observed. Five out of 7 patients (71%) became resectable (conversion), except for 2 with multiple lung metastases and bone metastasis prior to chemotherapy. Our historical conversion rates were, 0% (0/7) in 5FU/LV regimen from 1994 to 2003, 25% (7/27) other regimens such as FOLFIRI and FOLFOX except for FOLFOXIRI plus Bev from 2004. In 5 patients who became resectable, CR was not observed, however, all had PR after 6 cycles of chemotherapy (RR 100%). All 5 patients could undergo curative (R0) hepatic resection, furthermore, all had pathological major response (grade 2). Follow-up period ranged from 8 to 18 months, with a median period of 14 months, and 2 patients relapsed (lung recurrence and peritoneal dissemination), and one died of lung metastases (1.5-year OS and DFS are 80 % and 60%).

Conclusions: Our preliminary data suggested the feasibility of this new therapeutic combination in patients with initially unresectable liver metastases from colorectal cancer, and a high conversion rate and better prognosis.

[Table: see text]

The impact of bevacizumab on liver regeneration following hepatectomy in rats

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Background: In our clinical data, we had the interesting findings that the pathologic sinusoidal obstruction syndrome and serum hyaluronic acid after neoadjuvant oxaliplatin-associated chemotherapy for liver metastatic colorectal cancer with bevacitumab (Bev) was ameliorated compared to those without Bev. The purpose of this study was to investigate the influence of bevacizumab administration on regenerating liver in rat 70% and 90% hepatectomy (Hx) model as a surrogate model of human massive hepatectomy for liver metastatic colorectal cancer.

Methods: Male Wister rats weighing 180-230g were divided into the following four groups: 70%Hx, 70%Hx + Bev, 90%Hx and 90%Hx+Bev group. The rats were pretreated with intraperitoneal administration of bevacizumab (5mg/kg) 7 days before hepatectomy. The remnant liver and blood samples were taken one day after hepatectomy, and the following parameters were evaluated: blood analysis (AST, ALT, LDH, T- Bil, and hyaluronic acid), liver weight to body weight (Lw/Bw) ratio, and postoperative survival rate for three days.

Results: In the 70%Hx model, there was no significant difference between the 70%Hx group and 70%Hx + Bev group in blood analysis one day after hepatectomy; AST (1928 vs. 923 IU/L), ALT (1282 vs. 670 IU/L), T-Bil (0.17 vs. 0.19 mg/dl), LDH (3822 vs. 2967 U/L) and hyaluronic acid (995.7 vs. 1026.6 ng/ml) and in Lw/Bw ratio (1.78 vs. 1.84). In 90%Hx model, AST and ALT of blood analysis in 90%Hx+Bev group significantly decreased compared to those in 90%Hx group; AST (3428 vs. 4995 IU/L, P<0.05), ALT (1471 vs. 2287 IU/L, P<0.05), T-Bil (1.94 vs. 2.57 mg/dl), LDH (3229 vs. 5351 U/L) and hyaluronic acid (3865.7 vs. 7862.2 ng/ml). The Lw/Bw ratio in 90%Hx+Bev group significantly increased compared to that in 90%Hx group (0.80 vs. 0.67, P<0.05). The postoperative survival rate in 90%Hx+Bev group showed tendency to improve compared to that in 90%Hx group (75% vs. 50%, P=0.19).

Conclusions: The administration of bevacizumab seven days before hepatectomy did not significantly affect the liver functions and liver regeneration rate. These findings suggest that hepatectomy might be safe and feasible after the use of bevacizumab.

No significant financial relationships to disclose.

Effect of a histone deacetylase inhibitor on antitumor effect of gemcitabine to focus the gene network of ingenuity pathways analysis

230

Background: Histone deacetylase (HDAC) is strongly associated with epigenetic regulation and carcinogenesis, and its inhibitors induce the differentiation or apoptosis of cancer cells. Valproic acid (VPA) is one of the clinically available HDAC inhibitors. We previously showed that VPA augmented antitumor effect of GEM in choalngiocarcinoma cell line (2010 GI Symposium); this time, we performed microarray analysis and Ingenuity Pathways Analysis (IPA) to identify the systematic mechanism of the augmentative effect of VPA.

Methods: Human cholangiocarcinoma cell line (HuCCT1) was used. The anticancer effects of VPA or gemcitabine (GEM), and the effects of VPA combined with GEM were studied by MTT assay. We divided the following four groups: control group, VPA group, GEM group, VPA plus GEM combination group. The gene expressions of p21, HDAC, VEGF, and HIF-1 were evaluated by RT-PCR. And, the microarray analysis was performed, the genes were picked up using Gene Spring GX10, and then IPA was performed.

Results: In GEM alone group, no effect of GEM was observed in dose of 5 mm, and 16% of proliferation-inhibitory effects were observed in dose of 10 nm. In VPA alone group, no effect of VPA was observed in dose of 0.5 mm, and 12%, 35%, and 67% of proliferation-inhibitory effects were observed in dose of 1.0, 5.0, and 10mm, respectively. GEM (5 nm) and VPA (0.5 mm) reduced by 23%, which significantly augmented the anticancer effect of GEM alone or VPA alone (p<0.01). Furthermore, GEM combined with VPA upregulated the p21 expression compared with single agent (p<0.05). And, in regard to microarray analysis, we analyzed in 28,869 genes. The 24 genes were picked up with the comparison between VPA group and VPA plus GEM combination group using Gene Spring GX10, and the gene network of the cellular development containing the gene relevant to the differentiation of cancer cell, HLA-DR, was formed with IPA.

Conclusions: VPA augmented the effects of anticancer agents in a cholangiocarcinoma cell line. Such effects may be owing to the gene network of the cellular development. HDAC inhibitor may have the effect of the differentiation of cancer cell.

No significant financial relationships to disclose.

Role of histone deacetylase expression on regulating cancer stem cells in intrahepatic cholangiocarcinoma

219

Background: Histone deacetylase (HDAC) modulates gene expressions by chromatin remodeling during malignant transformation, and showed malignant behavior in intrahepatic cholangiocarcinoma (IHCC) (ASCO GI 2008). HDAC inhibitors have recently been found to repress the function of hypoxia inducible factors (HIF) through inducing hyperacetylation of histones. We also reported that the correlation between the expression of CD133, which was one of the cancer stem cell marker, and HIF-1α in IHCC (J Gastroenterol. 2010), and hypothesized that the cancer stem cell could be regulated by histone acetylation through the HIF-1α pathway. The aim of this study was to elucidate the potential mechanism of HDAC for the regulation of malignant behavior including the cancer stem cell in IHCC.

Methods: Thirty-five patients with IHCC who underwent hepatic resection were evaluated. The expressions of HDAC1 (sc-6298 Santa Cruz Biotechnology, USA), HIF-1α (NB100-105 Novus Biologicals, USA) and CD133 (Ab27699 Abcam Inc, UK) were determined immunohistochemically, and the patients were divided into two groups: HDAC1 positive group (n=21); and negative group (n=14). Clinicopathological variables including HIF-1α and CD133 expressions were analyzed according to these expressions.

Results: The HDAC1 expression correlated significantly with higher stage, lymph node metastasis, and vascular invasion. The prognosis in the HDAC1 positive group was poorer than in the HDAC1 negative group (5-year survival: 77.9% vs. 7.9%, p=0.001). In the multivariate analysis, HDAC1 positive expression was identified as the only independent prognostic factor for disease free survival (Hazard Ratio: 7.194, p=0.0018). There was a significant correlation between HDAC1 expression and HIF-1α expression (p=0.007), and also between HIF-1α expression and CD133 expression (p=0.10). Furthermore, co-expressions of these markers in same cancer cells were proven by immunofluorescent staining in the serial section.

Conclusions: The findings suggested that histone acetylation regulated cancer stem cell through the HIF-1α pathway; therefore, HDAC1 might be a possible promising molecular target in IHCC.

No significant financial relationships to disclose.

Radiological findings in acute Haemophilus influenzae pulmonary infection

OBJECTIVE

The aim of this study was to assess pulmonary thin-section CT findings in patients with acute Haemophilus influenzae pulmonary infection.

METHODS

Thin-section CT scans obtained between January 2004 and March 2009 from 434 patients with acute H. influenzae pulmonary infection were retrospectively evaluated. Patients with concurrent infection diseases, including Streptococcus pneumoniae (n=76), Staphylococcus aureus (n=58) or multiple pathogens (n=89) were excluded from this study. Thus, our study group comprised 211 patients (106 men, 105 women; age range, 16-91 years, mean, 63.9 years). Underlying diseases included cardiac disease (n=35), pulmonary emphysema (n=23), post-operative status for malignancy (n=20) and bronchial asthma (n=15). Frequencies of CT patterns and disease distribution of parenchymal abnormalities, lymph node enlargement and pleural effusion were assessed by thin-section CT.

RESULTS

The CT findings in patients with H. influenzae pulmonary infection consisted mainly of ground-glass opacity (n=185), bronchial wall thickening (n=181), centrilobular nodules (n=137) and consolidation (n=112). These abnormalities were predominantly seen in the peripheral lung parenchyma (n=108). Pleural effusion was found in 22 patients. Two patients had mediastinal lymph node enlargement.

CONCLUSION

These findings in elderly patients with smoking habits or cardiac disease may be characteristic CT findings of H. influenzae pulmonary infection.

Localised right upper-lobe pulmonary oedema caused by extension of giant cell carcinoma to the mitral valve

Giant cell carcinoma of the lung is a very rare primary malignant tumour and localised right upper-lobe pulmonary oedema is also unusual. We report a case of giant cell carcinoma, which invaded the left atrium through the left pulmonary vein and caused localised right upper-lobe pulmonary oedema.

Persistence of the single lineage of transmissible 'social cancer' in an asexual ant

How cooperation can arise and persist, given the threat of cheating phenotypes, is a central problem in evolutionary biology, but the actual significance of cheating in natural populations is still poorly understood. Theories of social evolution predict that cheater lineages are evolutionarily short-lived. However, an exception comes from obligate socially parasitic species, some of which thought to have arisen as cheaters within cooperator colonies and then diverged through sympatric speciation. This process requires the cheater lineage to persist by avoiding rapid extinction that would result from the fact that the cheaters inflict fitness cost on their host. We examined whether this prerequisite is fulfilled, by estimating the persistence time of cheaters in a field population of the parthenogenetic ant Pristomyrmex punctatus. Population genetic analysis found that the cheaters belong to one monophyletic lineage which we infer has persisted for 200-9200 generations. We show that the cheaters migrate and are thus horizontally transmitted between colonies, a trait allowing the lineage to avoid rapid extinction with its host colony. Although horizontal transmission of disruptive cheaters has the potential to induce extinction of the entire population, such collapse is likely averted when there is spatially restricted migration in a structured population, a scenario that matches the observed isolation by distance pattern that we found. We compare our result with other examples of disruptive and horizontally transmissible cheater lineages in nature.