Visual sex discrimination in goldfish: seasonal, sexual, and androgenic influences

The olfactory signals used by goldfish for sexual and aggressive communication have been studied extensively, but little work has addressed the role of other sensory modalities in social communication in this species. We therefore investigated the role that visual stimuli play in sex discrimination and the ability of androgens, which masculinize courtship behavior, to affect behavioral responses toward female visual stimuli. We found that males selectively orient toward female visual stimuli during the breeding season but not outside it, whereas prostaglandin F2-alpha (PGF2alpha)-injected females do not differentially approach male and female visual stimuli, even during the breeding season. Implanting adult females with testosterone (T) and 11-ketotestosterone (KT), however, induced orientation responses toward female visual stimuli similar to those observed in males. These results indicate that visual sexual stimuli are likely important for reproductive signaling in goldfish, potentially helping males identify ovulating females from a distance in a shoal of fish, and that androgens can influence mechanisms associated with orientation responses toward such stimuli.

Immunological and hematological effects observed in B6C3F1 mice exposed to JP-8 jet fuel for 14 days

JP-8 is the primary jet fuel used by the U.S. Air Force and NATO allies. Exposure is likely to be widespread and to include both military and aviation industry personnel as well as residents living near fuel contaminated sites. This study examines the effects of JP-8 on humoral and cell-mediated and hematological parameters. A suite of immunotoxicological endpoints was evaluated in adult female B6C3F1 mice gavaged with JP-8 (in an olive oil carrier) ranging from 250-2500 mg/kg/d for 14 d. One day following the last exposure, significant increases in liver mass were detected beginning at exposure levels of 1000 mg/kg/d, while thymic mass was decreased at exposure levels of 1500 mg/kg/d and above. Decreases in thymic cellularity, however, were only observed at exposure levels of 2000 mg/kg/d and above. Mean corpuscular volume was increased (1500-2500 mg/kg/d), while the hematocrit, hemoglobin concentration, and red blood cell count were decreased only at the 2500 mg/kg/d exposure level. Natural killer cell (NK) activity and T- and B-cell proliferation were not altered. Decreases in the plaque-forming cell (PFC) response were dose responsive at levels of 500 mg/kg/d and greater, while unexpectedly, serum levels of anti-SRBC immunoglobulin M (IgM) were not altered. Alterations were detected in thymic and splenic CD4/8 subpopulations, and proliferative responses of bone marrow progenitor cells were enhanced in mice exposed to 2000 mg/kg/d of JP-8. This study establishes that humoral immune function is impaired with lower exposure levels of JP-8 than are required to affect primary and secondary immune organ weights and cellularities, CD4/8 subpopulations, and hematological endpoints.

IPCS conceptual framework for evaluating a mode of action for chemical carcinogenesis

The International Programme on Chemical Safety (IPCS) is leading an activity to harmonize approaches to cancer risk assessment as a part of its larger project on the Harmonization of Approaches to the Assessment of Risk from Exposure to Chemicals. Through a series of workshops and the evaluation of case studies, a number of key components of risk assessments relating to harmonization were identified: transparency, terminology, weight of evidence, flexibility, and accessibility/communication. A major impediment to harmonization identified in the consideration of weight of evidence was the evaluation of mode of action. To address this need, a conceptual framework was developed, based on the general principles involved in considering the chemical induction of a specific tumor in animals. This is based partly on the Bradford Hill criteria for causality as modified by Faustman et al. (1997) for developmental toxicity. The framework is described in this paper followed by a worked example. It is recognized that the framework addresses only one stage in the overall characterization of hazard to humans of chemical carcinogens. Another important but separate step is the assessment of relevance to humans. This is a priority area for future work in this project.

Cryptophycin-induced hyperphosphorylation of Bcl-2, cell cycle arrest and growth inhibition in human H460 NSCLC cells

Bcl-2 has been described as a factor that can protect from apoptosis. The protective effect of Bcl-2 may be lost if the protein is phosphorylated. Bcl-2 phosphorylation can be induced by agents that affect microtubule depolymerization or prevent microtubule assembly. In 13 human tumor cell lines there was a high degree of heterogeneity in Bcl-2 protein expression. Human H460 non-small-cell lung carcinoma (NSCLC) cells expressed high levels of Bcl-2 and were selected for study. Western blot analysis for Bcl-2 phosphorylation was carried out after 4 h and 24 h of exposure to cryptophycin 52, cryptophycin 55, paclitaxel or vinblastine. Cryptophycin 52 and cryptophycin 55 were very potent inducers of Bcl-2 phosphorylation. After 4 h of exposure, Bcl-2 phosphorylation was evident with 0.05 nM cryptophycin 52, 0.25 nM cryptophycin 55, 5 nM vinblastine and 50 nM paclitaxel. The hyperphosphorylated form of Bcl-2 was evident after 24 h exposure of H460 cells to 0.25 nM cryptophycin 52 or cryptophycin 55 and 50 nM vinblastine or paclitaxel. The effects of the compounds on the cell cycle paralleled those on Bcl-2 phosphorylation. In H460 cells 90% cell killing was obtained with 0.13 nM cryptophycin 52, 0.2 nM cryptophycin 55, 20 nM paclitaxel and > 100 nM vinblastine after 24 h of exposure as determined by colony formation. In Bcl-2-negative Calu-6 NSCLC cells, 90% cell killing was obtained with 0.03 nM cryptophycin 52, 0.1 nM cryptophycin 55, 11 nM paclitaxel and 0.5 nM vinblastine using the same experimental design. Thus, cryptophycins are potent inducers of Bcl-2 phosphorylation. The cryptophycins were more potent cytotoxic agents in Bcl-2-negative Calu-6 cells than in Bcl-2-positive H460 cells indicating that pathways triggered by Bcl-2 phosphorylation are involved in cryptophycin-induced lethality.

Longitudinal study of moderate weight change and sleep-disordered breathing

CONTEXT

Excess body weight is positively associated with sleep-disordered breathing (SDB), a prevalent condition in the US general population. No large study has been conducted of the longitudinal association between SDB and change in weight.

OBJECTIVE

To measure the independent longitudinal association between weight change and change in SDB severity.

DESIGN

Population-based, prospective cohort study conducted from July 1989 to January 2000.

SETTING AND PARTICIPANTS

Six hundred ninety randomly selected employed Wisconsin residents (mean age at baseline, 46 years; 56% male) who were evaluated twice at 4-year intervals for SDB.

MAIN OUTCOME MEASURES

Percentage change in the apnea-hypopnea index (AHI; apnea events + hypopnea events per hour of sleep) and odds of developing moderate-to-severe SDB (defined by an AHI > or =15 events per hour of sleep), with respect to change in weight.

RESULTS

Relative to stable weight, a 10% weight gain predicted an approximate 32% (95% confidence interval [CI], 20%-45%) increase in the AHI. A 10% weight loss predicted a 26% (95% CI, 18%-34%) decrease in the AHI. A 10% increase in weight predicted a 6-fold (95% CI, 2.2-17.0) increase in the odds of developing moderate-to-severe SDB.

CONCLUSIONS

Our data indicate that clinical and public health programs that result in even modest weight control are likely to be effective in managing SDB and reducing new occurrence of SDB.

The appropriateness of admissions and the influences on a decision to admit

Within health services there is concern that escalating costs may reflect an inappropriate use of services and that services should avoid admitting patients who do not require acute care. The problem is, if these patients exist, how may they be identified and is this the sole consideration in patient management? This triangulated study examines the appropriateness of admissions, factors that influence that admission, and the potential to develop alternate models of care for medical patients. A utilization review, auditing 521 medical patients, provided a percentage of appropriateness of admission and stay, identified the barriers to discharge and those patients suitable for programs such as hospital in the home. Complementing the review, interviews with eight physicians explored how they decided to admit patients, what factors influenced that decision and their attitude to the development of these models of care.

MTA (LY231514) in combination treatment regimens using human tumor xenografts and the EMT-6 murine mammary carcinoma

An important component in the development of a new anticancer drug is an understanding of its potential for inclusion in combination treatment regimens. LY231514, a multitargeted antifolate (MTA), was tested in combination with cisplatin, methotrexate, 5-fluorouracil, paclitaxel, docetaxel, doxorubicin, LY329201 (a glycinamide ribonucleotide formyltransferase [GARFT] inhibitor), and fractionated radiation therapy in vivo using EMT-6 mammary carcinoma, human HCT 116 colon carcinoma, and human H460 nonsmall cell lung carcinoma grown as xenografts in nude mice. Isobologram methodology was used to determine the additivity or synergy of the combination regimens. MTA administered with cisplatin, paclitaxel, docetaxel, or fractionated radiation therapy produced additive to greater than additive tumor response by tumor cell survival assay and tumor growth delay. While an additive tumor response was observed when MTA was administered with methotrexate, synergistic tumor responses were seen when MTA was administered with the GARFT inhibitor, LY329201, or with the topoisomerase I inhibitor, irinotecan. MTA was administered in combination with full doses of each anticancer agent studied, with no evidence of increased toxicity resulting from the combination.

Thrombopoietin and its receptor, c-mpl, are constitutively expressed by mouse liver endothelial cells: evidence of thrombopoietin as a growth factor for liver endothelial cells

Present data suggest that the primary site of thrombopoietin (TPO) mRNA is the liver. Previously, we reported that specific murine liver endothelial cells (LEC-1) located in the hepatic sinusoids support in vitro megakaryocytopoiesis from murine hematopoietic stem cells suggesting that these cells may be a source of TPO. We report here that TPO and its receptor, c-mpl, are coexpressed on cloned LEC-1. Enzyme-linked immunosorbent assay (ELISA), biological assay, and flow cytometry studies confirmed the expression of both TPO and its receptor, respectively, at the protein level. TPO activity was enhanced in supernatants from LEC-1 treated with tumor necrosis factor (TNF)-alpha and gamma-interferon (INF). Our results show that TPO through its receptor stimulated the growth of LEC-1 in vitro. These observations establish LEC-1 as a novel source of TPO in the liver. To our knowledge, this is the first report that liver endothelial cells express both TPO and its receptor, c-mpl, and our findings indicate that this cytokine constitutes a growth factor for liver endothelial cells in vitro.

Transjugular core liver biopsy with a 19-gauge spring-loaded cutting needle

One hundred and five sequential transjugular core liver biopsies (TJLBx) were performed in 101 patients with coagulopathy and/or ascites using the 19-gauge Quick-Core Biopsy (QCB) needle. Two-hundred and seventy-three cores were obtained in 295 passes (92. 5%). One-hundred and two of the 105 procedures (97.1%) led to a histopathologic diagnosis. One of the three nondiagnostic biopsies was done because of severe autolysis of the liver. There was one subcapsular hematoma, one hepatic arteriovenous fistula, and one liver capsular puncture. Two minor neck hematomas occurred. One death was reported (unrelated to the procedure). QCB needle TJLBx is an effective and relatively safe way to obtain core liver samples.

Outbreak of Shigella sonnei in a clinical microbiology laboratory

Laboratory technologists (22%) developed infections with Shigella sonnei. The isolates had the same antibiogram and pulse-field gel electrophoresis pattern as an unknown isolate handled by a laboratory student. Covering faucet handles with paper towels during hand washing in the laboratory was protective. No further cases occurred after the laboratory was cleaned with a phenolic agent and a handle-free faucet was installed.

Cost Effectiveness Analysis of Hyperbaric Therapy in Osteoradionecrosis

In this time of fiscal restraint it is important to consider the costs and effectiveness of the treatments used whenever more than one treatment option is available. This paper presents an economic evaluation undertaken from a societal perspective to determine the cost effectiveness of using a modified hyperbaric oxygen (HBO) protocol to treat osteoradionecrosis of the mandible. Costs for the study group were obtained froma retrospective study of 21 patients who underwent a modified HBO protocol at the Hamilton Civic Hospitals, Hamilton, Ontario – a tertiary centre. A hypothetical control group was created and matched to the study group. Costs for this hypothetical conservative therapy group were calculated based on expected outcomes obtained from the literature. A sensitivity analysis was performed to determine the sensitivity to changes in the assumptions that were made and the data that were obtained from the literature. The modified HBO protocol was both less expensive and more effective than conservative therapy and, thus, demonstrated dominance. The number of days that each patient spends in the hospital is the key cost driver for conservative therapy treatment for osteoradionecrosis of the mandible. Patients who underwent the modified HBO protocol enjoyed greater pain reduction and increased sleep while requiring fewer narcotics.

Effects of global competition on health care administration in Finland and the United States. What you can do to save your practice

Global competition, a faltering Finnish economy, and deep recession are forcing difficult decisions on the health care administrators of this Nordic country known for its extensive social welfare safety net and socialized health care system. In the first part of this article the Finnish health care system and its problems, as well as possible solutions, are presented. Similarities to our own system are noted and discussed. In an interview, the director general for the Minister of Social Affairs and Health of Finland, Kimmo Leppo, expressed concern about future funding sources in his country for the same levels of social welfare and health care programs that presently exist. The Finns are considering managed competition among providers, increasing copayments, excess hospital beds, anticipated hospital closures in their country, block grants, and how to deal with rising physician unemployment. He was interested in the proposed US government health care plans, and especially the state of Tennessee's TennCare plan, a state plan that closely resembled the failed Clinton health care reform package. The second part of this article explores how global competition has brought the pressure of modern competitive economics into the US medical arena.

Antitrust implications of health care reform

Antitrust issues affect the insurance industry, hospital industry, and physicians. The authors explore the history of antitrust issues in the health care field and implications for future developments. Interest in antitrust has increased due to current merger and acquisition activities in the industry. With the failure of the Health Security Act, health care reform will be left to private industry. Will there be increasing or decreasing antitrust activity by the Department of Justice and Federal Trade Commission?

HIMeg-1, a cell line derived from a CML patient, is capable of monocytic and megakaryocytic differentiation

We have characterized HIMeg-1, a subclone of the promegakaryoblastic cell line HIMeg, in terms of its capability of proliferation and differentiation when it is exposed to various agents. We observed that phorbol 12-myristate 13-acetate (PMA) arrested HIMeg-1 growth and induced expression of monocytic surface antigens CD11c and CD14, but not the megakaryocytic surface antigen CD14a. In addition, PMA treatment of HIMeg-1 led to rapid activation of mRNA expression of egr-1, a transcription factor involved in regulating differentiation of hematopoietic progenitor cells. On the other hand, treatment of HIMeg-1 with the activated peripheral blood lymphocyte-conditioned medium (PBL-CM) resulted in greatly enhanced incorporation of 3H-thymidine into newly synthesized DNA. This enhanced 3H-thymidine incorporation appears to be specific to HIMeg-1 since the same concentrations of PBL-CM had little effect on the growth of the megakaryoblastic leukemia cell line SAM-1. The PBL-CM-induced DNA synthesis in HIMeg-1 was associated with activation of CD41a and CD41b surface antigen expression and down-regulation of expression of the erythroid marker glycophorin A and the early myeloid surface antigen CD33. HIMeg-1 capable of responding differentially to PMA and PBL-CM by changing its growth rate as well as its differentiation patterns will provide an ideal model to study the underlying mechanism regulating lineage restriction of hematopoietic progenitor cells.

Pharyngeal narrowing/occlusion during central sleep apnea

We hypothesized that subatmospheric intraluminal pressure is not required for pharyngeal occlusion during sleep. Six normal subjects and six subjects with sleep apnea or hypopnea (SAH) were studied during non-rapid-eye-movement sleep. Pharyngeal patency was determined by using fiber-optic nasopharyngoscopy during spontaneous central sleep apnea (n = 4) and induced hypocapnic central apnea via nasal mechanical ventilation (n = 10). Complete pharyngeal occlusion occurred in 146 of 160 spontaneously occurring central apneas in patients with central sleep apnea syndrome. During induced hypocapnic central apnea, gradual progressive pharyngeal narrowing occurred. More pronounced narrowing was noted at the velopharynx relative to the oropharynx and in subjects with SAH relative to normals. Complete pharyngeal occlusion frequently occurred in subjects with SAH (31 of 44 apneas) but rarely occurred in normals (3 of 25 apneas). Resumption of inspiratory effort was associated with persistent narrowing or complete occlusion unless electroencephalogram signs of arousal were noted. Thus pharyngeal cross-sectional area is reduced during central apnea in the absence of inspiratory effort. Velopharyngeal narrowing consistently occurs during induced hypocapnic central apnea even in normal subjects. Complete pharyngeal occlusion occurs during spontaneous or induced central apnea in patients with SAH. We conclude that subatmospheric intraluminal pressure is not required for pharyngeal occlusion to occur. Pharyngeal narrowing or occlusion during central apnea may be due to passive collapse or active constriction.