Genetic and phenotypic influences on copulatory plug survival in mice.

Across a diversity of animals, male seminal fluid coagulates upon ejaculation to form a hardened structure known as a copulatory plug. Previous studies suggest that copulatory plugs evolved as a mechanism for males to impede remating by females, but detailed investigations into the time course over which plugs survive in the female's reproductive tract are lacking. Here, we cross males from eight inbred strains to females from two inbred strains of house mice (Mus musculus domesticus). Plug survival was significantly affected by male genotype. Against intuition, plug survival time was negatively correlated with plug size: long-lasting plugs were small and relatively more susceptible to proteolysis. Plug size was associated with divergence in major protein composition of seminal vesicle fluid, suggesting that changes in gene expression may play an important role in plug dynamics. In contrast, we found no correlation to genetic variation in the protein-coding regions of five genes thought to be important in copulatory plug formation (Tgm4, Svs1, Svs2, Svs4 and Svs5). Our study demonstrates a complex relationship between copulatory plug characteristics and survival. We discuss several models to explain unexpected variation in plug phenotypes.

An assessment of lead controls for torch cutting and rivet removal on steel structures.

The use of engineering and work practice controls to protect workers from lead-containing dusts and fumes generated during rehabilitation of steel structures is mandated by the Occupational Safety and Health Administration (OSHA) Lead in Construction Standard (1993). Because the implementation and assessment of controls can be problematic in the rugged and dynamic construction environment, industrial hygienists should understand the effectiveness and limitations of controls adopted. The present investigation assesses the efficacy of two controls to reduce lead exposure: paint removal prior to oxy-acetylene torch cutting of steel, and encapsulation of rivets prior to their removal. A task-based exposure assessment approach was used to evaluate these tasks at three sites. Exposures at one site without controls were compared to exposures at sites with controls. Comparison of the results via an analysis of variance (0.05 significance level) indicates that, for torch cutting, exposures at the control site were not significantly different from those at an uncontrolled site (p = 0.14). The results for rivet busting show no significant differences in exposures at the control site compared to the uncontrolled site (p = 0.08). Results are also presented from two control sites where work was done in enclosed spaces. Two main difficulties in applying the controls are explored: technical and managerial. Technical problems during torch cutting included the penetration of paint into the steel profile and the configuration of the structures. For rivet busting, working within an enclosure was an important factor. Management problems arose both from a lack of coordination among different contractors, and from a failure to provide day-to-day guidance and assessment of the control. Important components of a program to implement controls are preplanning and coordination of control implementation, frequent testing of control efficacy, and a method for timely intervention to correct deficiencies.

Less common orbital fracture patterns: the role of computed tomography in the management of depression of the inferior oblique origin and lateral rectus involvement in blow-in fractures.

During the past decade, advances in radiographic imaging have made it possible for the surgeon managing orbital fractures to adopt a rational therapeutic strategy based on a knowledge of alterations in surgical anatomy secondary to traumatic injury. To illustrate the value of computed tomography in the surgeon's armamentarium for management of orbital fractures, cases are presented in which imaging proved decisive in planning a course of therapy. Two patients presented with two types of isolated lateral blow-in fracture, an uncommon fracture pattern. The other cases underscore the value of defining involvement of the inferior oblique origin and lateral rectus muscles in imaging complex orbital fractures, issues not emphasized in earlier literature. Although diplopia alone does not always warrant surgical intervention, diplopia in the context of computed tomography-defined muscle entrapment or muscle origin displacement justifies operative therapy. These cases demonstrate the value of computed tomography in directing surgical therapy with resolution of diplopia and prevention and correction of enophthalmos.

Patterns of sealant delivery under variable third party requirements.

Despite evidence indicating dental sealants to be effective in preventing caries on the pit and fissure surfaces of teeth, only 8 percent of school-aged US children had received sealants as of 1986-87. While many rationales have been suggested and scientifically answered for this low level of utilization, issues of cost and cost effectiveness remain considerable barriers to many insurers and public programs. This study reports dentist behavior when sealants were added with few restrictions as a new benefit to an existing third party system of care. Results are compared to another third party program with stricter reimbursement policies. Overall, sealants were provided in a reasonable fashion to both groups of patients, relative to teeth selected for sealing and costs. Only a small proportion of patients receiving sealants were under age six or above age 19. Even under the most liberal program, sealants were predominantly targeted to teeth at highest risk to decay. Still, for both groups, a significant proportion of the sealants were placed in teeth at points in time quite distant from expected eruption patterns and, thus, their periods of highest risk to decay. Overall, dentists appeared to use sealants only minimally in their practices. These data suggest that sealants can be added to third party dental programs with little overall risk of inappropriate use or abuse. They also suggest that specific efforts are merited to educate providers as to the most effective times at which to provide sealants for preventing the maximum amount of decay in a population.

Managing organizational stress in nursing.

The strategic management of a nursing organization in a changing health care market creates pressure on nursing administrators and on their organizations. The effective management of organizational stress potentiates quality nursing care and reduces the costs related to stress and burnout. This article describes a two-tiered program designed to manage organizational stress. The first component focuses on educating nursing leadership about the nature and impact of organizational stress and how to minimize it. The second component is the instrument used to measure the perceived effectiveness of our interventions.

The human resource consultant in nursing.

The authors have developed a role that supports nurse managers in developing their management skills and effectiveness. Nursing administrators will find the role useful because it provides a different avenue for the strategic planning of change. The role and examples of its use in the support of nursing are described. Considerations in operationalizing this role in a nursing organization also are discussed.