Somatic mutations of epidermal growth factor receptor in colorectal carcinoma.

PURPOSE: Somatic mutations of the epidermal growth factor receptor (EGFR) gene may predict the sensitivity of non-small cell lung carcinoma to gefitinib. However, no mutations have been reported for colorectal carcinoma. We therefore analyzed EGFR mutations in colorectal adenocarcinomas by the combined use of laser microdissection and sequencing of genomic DNA. EXPERIMENTAL DESIGN: We examined 11 representative colorectal adenocarcinoma cell lines and 33 clinical samples of colorectal carcinoma. In the clinical cases, we carefully dissected only carcinoma cells from frozen sections by laser microdissection. After DNA extraction and PCR, we examined EGFR mutations by sequencing genomic DNA. RESULTS: None of 11 colorectal carcinoma cell lines exhibited somatic mutations, but 4 of 33 clinical tumors (12%) exhibited mutations in the EGFR kinase domain. This may be the first report of somatic mutations in colorectal adenocarcinoma. CONCLUSIONS: Our findings suggest that a distinct minority of colorectal adenocarcinomas exhibit somatic mutations of EGFR, and these tumors may be susceptible to gefitinib treatment.     

Fatigue-induced changes in longitudinal relaxation time determined by magnetic resonance imaging

Longitudinal relaxation time (T₁) determined by 3.0-T magnetic resonance imaging of the tibialis anterior and extensor digitorum longus muscles increased gradually with muscle fatigue caused by three 120-s periods of repeated ankle dorsiflexion separated by 5-min rest periods. T₁ values decreased in the recovery period, although they remained higher than the preexercise values. T₁ values for the soleus muscle were unchanged throughout the experiment. Results suggest that muscle T₁ values increase with increasing muscle fatigue.     

Histopathological studies of microtubule disassembling agent-induced myocardial lesions in rats

Microtubule disassembling agents (MDAs) such as colchicine (COL) and vincristine sulfate (VCR) are known to be cardiotoxic. However, few attempts have been made to histopathologically examine cardiac lesions induced by MDAs. In this study, we endeavored to induce myocardial injury in rats by administering MDAs and to clarify the morphological features of these myocardial lesions. Male rats were intravenously administered COL (1.00 or 1.25 mg/kg for 2 days at single daily doses) or VCR (0.50 or 0.75 mg/kg for 2 days at single daily doses). The day after administration, hearts were excised and examined histopathologically, immunohistochemically and electron microscopically. Degeneration and necrosis of myocardial cells with vacuolation were observed in rats administered COL at 1.25 mg/kg or VCR at 0.75 mg/kg. Electron microscopic examination revealed vacuoles in swollen mitochondria. Moreover, there were cells showing pyknosis and karyorrhexis in the interstitium. TUNEL and immunohistochemical staining for endothelial cells and electron microscopic examination identified the apoptotic cells in the interstitium to be vascular endothelial cells. These vascular endothelial lesions were induced by lower doses of MDAs than were myocardial lesions. Furthermore, common sites of cardiac lesions induced by MDAs had almost the same distribution as areas positive for pimonidazole, a marker of hypoxia. These findings indicate that MDAs occasionally damage mitochondria in myocardial cells, and suggest that these changes involve microcirculatory dysfunction induced by endothelial cell injury.     

Fcγ receptor 3B polymorphism is associated with hypersensitivity reactions to adalimumab in Japanese patients with rheumatoid arthritis

Objectives: To examine the association between Fcγ receptor (FcγR) polymorphisms and the development of hypersensitivity reactions to adalimumab in patients with rheumatoid arthritis.

Methods: Sixty-five patients receiving adalimumab were enrolled in the study. Genetic polymorphisms for FcγR3B were genotyped in FCGR3B NA1/2 alleles by real allelic discrimination assay. Clinical information and the occurrence of a hypersensitivity reaction to adalimumab were collected from the patients’ charts.

Results: A hypersensitivity reaction was observed in 12% of the patients. Clinical information obtained from patients with a reaction and those without were the same. The FCGR3B NA1/NA1, NA1/NA2, and NA2/NA2 alleles were found in 75%, 13%, and 13% of the patients with hypersensitivity reaction, respectively, and in 28%, 42%, and 30% of those without a hypersensitivity reaction, respectively (p?=?0.04). Multivariate logistic regression analysis identified only the NA1/NA1 as an independent relevant factor for a hypersensitivity reaction to adalimumab (OR 7.7, p?=?0.01).

Conclusions: The FCGR3B NA1/NA1 genotype is associated with hypersensitivity reactions to adalimumab.     

A Novel Approach to Detecting Postpartum Hemorrhage Using Contrast-Enhanced Ultrasound

The aim of this study was to estimate the efficacy of contrast-enhanced ultrasound (CEUS) in detecting postpartum hemorrhage (PPH) after cesarean section. This is the first study of CEUS in obstetric hemorrhage. A total of 37 patients, operated at Nagoya University Hospital, underwent CEUS. We evaluated the findings of CEUS, which were qualitatively defined as positive when pooling or leakage of contrast agent was observed in the uterine cavity, by measuring the amount of bleeding during the first 4 h after cesarean section. The time–intensity curve patterns of leaked contrast agents were also analyzed for quantitative prediction of the amount of blood loss. Significant differences between the excessive hemorrhage (N = 7) and non-excessive hemorrhage groups (N = 30) were noted in the occurrence of positive CEUS (p = 0.011). Additionally, mean postpartum blood loss markedly increased in patients with a positive CEUS (p = 0.002). From a quantitative perspective, the time until leakage of contrast agents was detected correlated with the amount of bleeding, but the other characteristics of the time–intensity curve pattern did not provide valuable information. In conclusion, CEUS, which enables bedside assessment and rapid diagnosis, is a promising strategy for the detection of PPH.     

Cardiac angiotensin II type 2 receptor activates the kinin/NO system and inhibits fibrosis

We have previously demonstrated that stimulation of the angiotensin (Ang) II type 2 receptor in vascular smooth muscle cells caused bradykinin production by activating kininogenase in transgenic mice. The aim of this study was to determine whether overexpression of AT2 receptors in cardiomyocytes attenuates Ang II-induced cardiomyocyte hypertrophy or interstitial fibrosis through a kinin/nitric oxide (NO)-dependent mechanism in mice. Ang II (1.4 mg/kg per day) or vehicle was subcutaneously infused into transgenic mice and wild-type mice for 14 days. The amount of cardiac AT2 receptor relative to AT1 receptor in transgenic mice was 22% to 37%. Ang II caused similar elevations in systolic blood pressure (by approximately 45 mm Hg) in transgenic mice and wild-type mice. Myocyte hypertrophy assessed by an increase in myocyte cross-sectional area, left ventricular mass, and atrial natriuretic peptide mRNA levels were similar in transgenic and wild-type mice. Ang II induced prominent perivascular fibrosis of the intramuscular coronary arteries, the extent of which was significantly less in transgenic mice than in wild-type mice. Inhibition of perivascular fibrosis in transgenic mice was abolished by cotreatment with HOE140, a bradykinin B2 receptor antagonist, or L-NAME, an inhibitor of NO synthase. Cardiac kininogenase activity was markedly increased (approximately 2.6-fold, P<0.001) after Ang II infusion in transgenic mice but not in wild-type mice. Immunohistochemistry indicated that both bradykinin B2 receptors and endothelial NO synthase were expressed in the vascular endothelium, whereas only B2 receptors were present in fibroblasts. These results suggest that stimulation of AT2 receptors present in cardiomyocytes attenuates perivascular fibrosis by a kinin/NO-dependent mechanism. However, the effect on the development of cardiomyocyte hypertrophy was not detected in this experimental setting.