Expression of aquaporin 1 in primary renal tumors: a prognostic indicator for clear-cell renal cell carcinoma

Background

Aquaporin 1 (AQP1) is a water channel expressed in many epithelial tissues and endothelium, including the proximal nephron of the kidney.

Objective

We measured AQP1 expression in primary renal cell carcinomas (RCCs) and evaluated its significance and prognostic utility.

Design, setting, and participants

We examined AQP1 expression in 559 sporadic renal tumors as well as in 43 normal kidney tissue samples and collected clinicopathologic and prognostic data.

Measurements

AQP1 expression was measured by using real-time quantitative polymerase chain reaction (PCR).

Results and limitations

All normal kidney samples presented substantial AQP1 expression. Among tumor subtypes, AQP1 expression was significantly higher in clear-cell and papillary RCCs, whereas it was lower in chromophobe RCCs, oncocytomas, and collecting-duct carcinomas. In clear-cell RCC, AQP1 was significantly higher in patients without symptomatic presentation or whose tumors were smaller, lower grade, or either lower stage or lacking in microvascular invasion. Von Hippel-Lindau (VHL) tumor suppressor gene mutational status did not affect expression level. Cox univariate and multivariate analyses strongly associated high AQP1 expression with better prognosis in cancer-specific and cancer-free survival tests in all patient cohorts, as well as in cancer-specific survival in a cohort of patients with advanced metastatic RCC. The time-dependent receiver operation characteristic (ROC) analyses, combined with logistic regression models, revealed that the addition of the AQP1 parameter to the University of California Los Angeles Integrated Staging System (UISS) prognostic score can improve the accuracy of predictions of both cancer death and recurrence for all patient cohorts as well as of cancer death for advanced cases within a 5-yr follow-up period in clear-cell RCC. High AQP1 expression was also associated with better outcome in a univariate cancer-specific survival test in papillary RCCs.

Conclusions

AQP1 shows RCC subtype-specific expression, and its expression level provides useful prognostic information for patients with clear-cell RCC.     

Usefulness of computed tomography during cholangiography for the diagnosis of multiple hepatic peribiliary cysts: a report of three cases with chronic liver disease

Hepatic peribiliary cysts are composed of multiple tiny cysts along the larger portal tracts and have been reported to be harmless. On clinical images, peribiliary cysts resemble other diseases such as biliary dilatations, cholangitis, or periportal edema. Therefore, it is important to distinguish peribiliary cysts from these diseases using a combination of several imaging modalities. Herein, we report three cases of peribiliary cysts. The first case underwent laparotomy for the presumptive diagnosis of intrahepatic cholangiocarcinoma. In the remaining two cases, hepatic peribiliary cysts were diagnosed and laparotomy was avoided. Magnetic resonance cholangiography contributed to the diagnosis, owing to their characteristic distribution. In addition, computed tomography during cholangiography (cholangio-CT) demonstrated that the cysts had no communication with the intrahepatic biliary system. Therefore, cholangio-CT is considered to be the most useful modality for the diagnosis of peribiliary cysts.     

Safety of laparoscopic intracorporeal rectal transection with double-stapling technique anastomosis

To assess the feasibility and analyze the short-term outcomes of laparoscopic intracorporeal rectal transection with double-stapling technique anastomosis, a review was performed of a prospective registry of 67 patients who underwent laparoscopic sigmoidectomy and anterior resection with intracorporeal rectal transection and double-stapling technique anastomosis between July 2001 and January 2004. Patients were divided into 3 groups: sigmoid colon/rectosigmoid carcinoma, upper rectal carcinoma, and middle/lower rectal carcinoma. A comparison was made of the short-term outcomes among the groups. The number of cartridges required in bowel transection was significantly increased in patients with middle/lower rectal carcinoma, and significant differences were observed in the length of the first stapler cartridge fired for rectal transection. Furthermore, mean operative time and blood loss were also significantly greater in the middle/lower rectum group; however, complication rates and postoperative course were similar among the 3 groups. No anastomotic leakage was observed. Laparoscopic intracorporeal rectal transection with double-stapling technique anastomosis can be performed safely without increased morbidity or mortality.     

A randomized study of prophylactic intravesical instillation of pirarubicin (THP) prior to transurethral resection of superficial bladder cancer

A prospective randomized study was conducted to evaluate the efficacy of prophylactic intravesical instillation of pirarubicin (THP) prior to transurethral resection (TUR) of superficial bladder cancer. A total of 63 patients were randomized into two groups, the THP group and the control group. In the THP group, 30 mg of THP dissolved in 50 ml saline was administered 4 times intravesically for 4 consecutive days before TUR. In the control group, no instillation was performed before TUR. The patients were followed by cystoscopy and urinary cytology every 3 months. The non-recurrence rates in the THP group and control group were 54.1% versus 37.6% at 1 year and 40.4% versus 26.8% at 2 years, respectively (P = 0.086). Time to recurrence for tumors larger than 1 cm was significantly longer in the THP group (P = 0.0137). Time to recurrence for single and grade 1+2 tumors tended to be longer in the THP group (P = 0.09, P = 0.079). No significant adverse effects were observed in any patient. Our findings suggest that intravesical THP instillation prior to TUR would be effective for patients with single, low grade lesions larger than 1 cm of superficial bladder cancer.     

Drug-induced hypersensitivity syndrome due to mexiletine associated with human herpes virus 6 and cytomegalovirus reactivation

A 66-year-old man developed a fever of 38 degrees C and generalized pruritic rash about one month after mexiletine hydrochloride administration for ventricular tachycardia. The rash appeared as edematous erythema and papules with purpura on the lower extremities. Liver dysfunction, leukocytosis, and atypical lymphocytes were also present. Elevated antibody titer against human herpes virus 6 (HHV-6) was detected during the course of the disease (1:20 -> 1:640). The patient was diagnosed as having drug-induced hypersensitivity syndrome (DIHS) due to mexiletine. Discontinuation of the mexiletine administration and systemic corticosteroid treatment led to a temporary improvement, but tapering the corticosteroid dose twice led to recrudescence. Simultaneous with the recrudescence, elevated antibody titers against HHV-6 and cytomegalovirus were detected, as well as viral DNA in the blood, suggesting that these two viruses may have been involved in the recrudescence. The patient died of myocarditis, most likely related to cytomegalovirus. Our case indicates that, in addition to HHV-6, other herpes viruses such as cytomegalovirus can be reactivated in DIHS and may modify the clinical disease activity.     

Measurement of airway resistance in anesthetized and paralyzed subjects: Proposal for evaluation of K1 values

The effects of lung volume and respiratory airflow on airway resistance were studied in five anesthetized and paralyzed patients. Airway resistance measured during the inspiratory phase with intermittent constant airflow inflatoins decreased in inverse correlationship to increases in lung volume. Airway resistance measured during the expiratory phase with an airway interruption technique, on the other hand, increased with a linear relationship to the expiratory airflow as expressed by a function of Y = K₁ + K₂X. K₁, calculated from the values of airway resistance corresponding to three different airflows, was unaffected by intentional expiratory resistance loading. Thus, simultaneously with the measurement of airway resistance by this method, expiratory gas sampling with a Douglas bag can be done if necessary. Since the K₂ value of the endotracheal tube used in this study (Portex^® I.D. 8mm, length 26cm) was quite high (5.0cmH₂O·1^–2·sec²), depending on the airflow, the presence of the endotracheal tube strongly affected the measurement of airway resistance during general anesthesia. K₁ measured by the above method, however, may be considered as the best way to evaluate the lower airway resistance independent of either lung volume or expiratory airflow.(Sakai T, Yoshida H, Yano H et al.: Measurement of airway resistance in anesthetized and paralyzed subjects: proposal for evaluation of K₁ values. J Anesth 2: 139–145, 1988)     

Early colon cancers detected by FDG-pet: a report of two cases with immunohistochemical investigation

Increased glucose uptake is one of the metabolic characteristics of tumor cells. 18F-fluorodeoxyglucose (FDG)-positron emission tomography (FDG-PET), a technique that is used widely to study this altered glucose metabolism in tumors, allows the detection of various types of malignancy. We present herein two cases of early colon cancers detected incidentally by FDG-PET. The technique was used as part of the screening examinations for preoperative staging, and for postoperative follow-up. In both cases, the lesions were removed by colonoscopic polypectomy, with no complications. Moreover, we confirmed the existence of altered glucose metabolism in the resected specimen by immunohistochemical staining using an antibody raised against Glut1. Immunohistochemically, Glut1 was expressed in vitro in both of the lesions, supporting the positive FDG-PET result obtained in vivo. To our knowledge, this is the first report to describe in vitro Glut1 expression and in vivo tumor detection using FDG-PET in colorectal carcinoma.