A general swimming response in exhausted obligate swimming fish.

Marine organisms normally swim at elevated speeds relative to cruising speeds only during strenuous activity, such as predation or escape. We measured swimming speeds of 29 ram ventilating sharks from 10 species and of three Atlantic bluefin tunas immediately after exhaustive exercise (fighting a capture by hook-and-line) and unexpectedly found all individuals exhibited a uniform mechanical response, with swimming speed initially two times higher than the cruising speeds reached approximately 6 h later. We hypothesized that elevated swimming behaviour is a means to increase energetic demand and drive the removal of lactate accumulated during capture via oxidation. To explore this hypothesis, we estimated the mechanical work that must have been spent by an animal to elevate its swim speed and then showed that the amount of lactate that could have been oxidized to fuel it comprises a significant portion of the amount of lactate normally observed in fishes after exhaustive exercise. An estimate for the full energetic cost of the catch-and-release event ensued.

Prognostic significance of percentage of bronchioloalveolar pattern in adenocarcinomas of the lung.

Bronchioloalveolar (BA) carcinoma of the lung is considered to have a better prognosis than that of common adenocarcinomas of the lung. However, a minor component of the BA pattern is common in many lung adenocarcinomas and the criteria for designating an adenocarcinoma as BA are not well defined. We assessed the clinicopathologic features of 238 cases of lung adenocarcinoma with a partial or predominant BA pattern. Tumors were classified as BA if more than 75% of the tumor had a BA growth pattern. In other words, the tumor grew along pre-existing lung structures without invasion or destruction of parenchyma. Tumors with 50% to 75% BA pattern were considered mixed and tumors with less than 50% BA pattern were designated as solid/acinar (S/A). Fixed, paraffin-embedded tissue sections of each neoplasm were also assessed using immunohistochemical methods with a panel of antibodies specific for p53, retinoblastoma protein, p16, cyclin D1, and cyclin E, and the results were correlated with clinical and pathologic parameters. Our results show that the 5-year survival rate of patients with BA and mixed tumors, 63% and 60%, respectively, was significantly better than that of patients with S/A tumors (P =.026). Patients with BA tumors were more frequently women (55.9%) compared with patients with mixed (48.3%) and S/A (43.8%) tumors. Bronchioloalveolar and mixed tumors were similarly associated with tobacco use, 88.2% and 85%, respectively; slightly less than S/A tumors (93.8%). Clinical and pathologic parameters did not correlate with immunohistochemical results. In conclusion, patients with BA or mixed tumors have similar 5-year survival, better than that of patients with S/A tumors, suggesting that adenocarcinomas can be designated as BA when at least 50% of the tumor has a BA pattern.

The expression of cyclins D1 and E in predicting short-term survival in squamous cell carcinoma of the lung.

Cyclins D1 (cD1) and E (cE) are G1 phase cyclins believed to participate in the pathogenesis of malignancy. Overexpression of cD1 has been reported to influence prognosis in squamous cell carcinomas (SCC) of the larynx, but was not significant in a limited study of non-small cell lung cancers (NSCLC). Altered expression of cE has been proposed as another potential prognostic marker in malignancy but its possible role in NSCLC has not been elucidated. In order to determine the prognostic value of cD1 and cE in NSCLC, paraffin-embedded sections of 467 NSCLC were immunostained with monoclonal antibody to cD1 (1:500, PharMingen, San Diego, CA) and 400 NSCLC with MA to cE (1:2500, PharMingen) using an enhanced sensitivity avidin-biotin complex technique. The number of tumor cells with nuclear and/or cytoplasmic immunopositivity was graded on a scale of: 0 = less than 1%, 1 = 1 to 10%, 2 = 10 to 25%, 3 = 25 to 50%, 4 = 50 to 75%, 5 = more than 75%. Results were correlated with survival by Kaplan-Meier survival plot using Stat-View software (Abacus Concepts, Berkeley, CA). Overall, 426 NSCLC with cD1 and 360 NSCLC with cE had adequate follow-up (median, 76 mo) for survival analysis. Both cyclins independently showed significance in prognosis of SCC but not other cell types. For cD1, absence of immunostaining was associated with worse prognosis than any immunopositivity for all stages of SCC (P = .025). For cE, Stage I and II SCC with less than 50% immunopositivity had a worse prognosis (P = .029). Of 70 Stage I and II SCC immunostained for both monoclonal antibodies, 55% of patients with tumors that demonstrated both absence of cD1 staining and cE immunopositivity in less than 50% of cells were dead at 5 years compared to 35% of patients with tumors that demonstrated positive staining with cD1 and cE immunopositivity in more than 50% of cells. These results strongly suggest cD1 and cE can independently predict prognosis in early stage SCC. Worse prognosis was associated with loss of expression, consistent with mechanisms other than overexpression of these cyclins in the progression of SCC.

Natural killer-cell lymphoma involving the gynecologic tract.

Non-Hodgkin lymphomas (NHL) can involve the gynecologic tract, most often as a manifestation of systemic involvement, and most cases reported have been of B-cell lineage. We describe 2 women with natural killer (NK)-cell lymphoma involving the gynecologic tract that initially presented with vaginal bleeding. In case 1, the patient had a stage IE nasal-type NK-cell lymphoma involving the cervix. The tumor was composed of medium-sized, irregular lymphoid cells with angioinvasion and necrosis. In case 2, the patient had a stage IV blastoid NK-cell lymphoma/leukemia infiltrating all organs in a hysterectomy and bilateral salpingo-oophorectomy specimen. Subsequent biopsy specimens revealed that the bone marrow and lymph nodes were also involved. The neoplasm was composed of small to medium lymphoid cells with fine nuclear chromatin. Case 1 was assessed immunohistochemically and the neoplastic cells were positive for CD3, CD56, and TIA-1. Case 2 was analyzed using both immunohistochemical and flow cytometry methods. The neoplastic cells were positive for cytoplasmic CD3, CD4, CD7, CD43, CD45, and CD56 and were negative for surface CD3. Both cases were negative for Epstein-Barr virus (EBV) ribonucleic acid (RNA) and molecular studies showed no evidence of T-cell receptor gamma chain gene rearrangements. The immunophenotype and absence of T-cell receptor gene rearrangements support NK-cell origin. We report these cases to illustrate that NK-cell lymphomas can involve, and rarely arise in, the gynecologic tract.

Pseudobacteremia traced to cross-contamination by an automated blood culture analyzer.

Twenty-three episodes of pseudobacteremia occurring over a seven-month period were traced to cross-contamination by the automated blood culture analyzer (BACTEC 460) used in the microbiology laboratory. An epidemiologic investigation of an unusual cluster of three patients with pseudobacteremia caused by oxacillin-resistant Staphylococcus aureus led to the identification of the problem. Mock trials of the blood culture procedure confirmed that the blood culture analyzer was the source of contamination. After the needle sterilizer was replaced by the manufacturer, the problem of cross-contamination abated. Contamination of sterile blood cultures by an instrument intended to identify bacteremia rapidly may lead to incorrect diagnosis, unnecessary administration of antibiotics and prolonged hospitalization. Because of the widespread use of automated blood culture analyzers in the US, physicians, microbiologists, and infection control personnel should be alert to the possibility of cross-contamination and the subtle way in which it may present.