DEG1, encoding the tRNA:pseudouridine synthase Pus3p, impacts HOT1-stimulated recombination in Saccharomyces cerevisiae

In Saccharomyces cerevisiae, HOT1-stimulated recombination has been implicated in maintaining homology between repeated ribosomal RNA genes. The ability of HOT1 to stimulate genetic exchange requires RNA polymerase I transcription across the recombining sequences. The trans-acting nuclear mutation hrm3-1 specifically reduces HOT1-dependent recombination and prevents cell growth at 37 degrees . The HRM3 gene is identical to DEG1. Excisive, but not gene replacement, recombination is reduced in HOT1-adjacent sequences in deg1Delta mutants. Excisive recombination within the genomic rDNA repeats is also decreased. The hypo-recombination and temperature-sensitive phenotypes of deg1Delta mutants are recessive. Deletion of DEG1 did not affect the rate of transcription from HOT1 or rDNA suggesting that while transcription is necessary it is not sufficient for HOT1 activity. Pseudouridine synthase 3 (Pus3p), the DEG1 gene product, modifies the anticodon arm of transfer RNA at positions 38 and 39 by catalyzing the conversion of uridine to pseudouridine. Cells deficient in pseudouridine synthases encoded by PUS1, PUS2 or PUS4 displayed no recombination defects, indicating that Pus3p plays a specific role in HOT1 activity. Pus3p is unique in its ability to modulate frameshifting and readthrough events during translation, and this aspect of its activity may be responsible for HOT1 recombination phenotypes observed in deg1 mutants.

Pharmacokinetics of sufentanil in patients undergoing coronary artery bypass graft surgery

OBJECTIVE

To determine the pharmacokinetics of sufentanil in patients undergoing coronary artery bypass graft surgery.

DESIGN

Prospective, multigroup study.

SETTING

University-affiliated hospital.

PARTICIPANTS

Patients with good left ventricular function undergoing elective surgery (n = 103).

INTERVENTIONS

Sufentanil was administered by target-controlled infusion, with target effect-site concentrations ranging from 0.4 to 4.5 ng/mL. Isoflurane was administered as required to maintain stable hemodynamics. Sufentanil pharmacokinetics were determined by population modeling. The potential effects of gender, weight, different premedications (lorazepam, morphine-scopolamine, or clonidine), and coinduction with propofol on sufentanil pharmacokinetics were explored.

MEASUREMENTS AND MAIN RESULTS

The first model determined was a simple 3-compartment model, without any covariates, which had these parameters: V(1) = 5.7 L, V(2) = 18.1 L, V(3) = 225 L, Cl(1) = 0.69 L/min, Cl(2) = 3.1 L/min, and Cl(3) = 1.4 L/min. The overall predictive ability during the entire pre-cardiopulmonary bypass period of this model was excellent, with virtually no bias (median prediction error, -0.4%) and good precision (median absolute prediction error, 18.4%). More complex models with the various premedications used or coinduction with propofol as covariates did not improve the predictive accuracy or precision compared with the simple 3-compartment model. Similarly, including either gender or weight as a covariate did not improve predictive ability.

CONCLUSION

The authors have determined a pharmacokinetic model for sufentanil that can be used to maintain desired target concentrations of sufentanil before cardiopulmonary bypass, with a high degree of accuracy and acceptable variability. Concomitantly administered medications (lorazepam, morphine-scopolamine, clonidine, or propofol) do not appear to have any clinically important effects on distribution-phase sufentanil pharmacokinetics.

A moving target: financing Medicare for the future

Since 1997, there has been a steady downward trend in projected Medicare spending as a share of the gross domestic product (GDP), substantially improving the long-run outlook for Medicare. But even with improvements in outlook, the required share of GDP will rise by more than 70%, and the question remains as to who will pay for Medicare in the future. This report examines a limited set of tax options and a flat beneficiary premium to illustrate the size of contributions necessary to achieve several different goals, and to explore the difference that multiple years of projections can make on these requirements.

The special health care needs of the elderly

Interest in Medicare, the government's second largest social program after Social Security, reached a new high in 1995, not as part of health care reform, but as a vehicle for deficit reduction and because of a desire by Congress to restructure the program to encourage enhanced choice for beneficiaries and greater use of managed care. Medicaid, a major payer of long-term care and financer of coverage for low-income elderly, also is slated to undergo major restructuring in the next few years. As Congress and the nation debate the future of these key programs for older Americans, a number of critical issues deserve attention. Medicare's costs are very high--but not necessarily unreasonable in the face of the demands on health care services for this part of the population. And even with these high costs, a number of important gaps in coverage remain a problem for seniors. Deductibles and copayments are also high--especially for hospital and skilled nursing services. But pressure for change may well lead to higher, not lower, cost-sharing requirements. Medicare remains a largely fee-for-service program at a time when the national health care system is shifting increasingly to a managed care environment. Moving Medicare in that direction is one likely option for change. While it is desirable to have Medicare move in concert with the rest of the system, a number of issues stand in the way of an effortless move to managed care for the elderly. Moreover, coordination of long-term and acute care services may be even more challenging in such an environment. Medicaid covers long-term care services for older Americans, but only for those who have depleted most of their assets and income. Even when people do become eligible, Medicaid covers primarily institutional care. But little is likely to change this picture in the next few years, and private efforts through expansion of long-term care insurance will likely provide only a partial solution.

Post-operative computed tomography in two dogs with cerebral meningioma

Post-operative computed tomography (CT) has been described as a technique for diagnosing incomplete resection or recurrence of cerebral neoplasms in humans. The characteristics of immediate postoperative CT images in dogs with intracranial pathology are unknown. This report describes findings from preoperative, immediate post-operative, and 4 week to 9 month follow-up CT examinations in two dogs with histologically-confirmed cerebral meningiomas. In images of one dog after surgery there was mild contrast enhancement of the tissue surrounding the surgical site. This enhancement had resolved in later images and was probably the result of surgically induced trauma. In post operative images of the other dog there was significant hyperattenuation of the tissues around the surgical site. In post contrast images there was increased enhancement that was evident in later images. These findings, although not supported by necropsy, probably indicate incomplete excision of the tumor.

Women's characteristics and gender role attitudes: support for father involvement with children

Women's (N = 364) personal characteristics and gender role attitudes were examined in relation to their support for father involvement with children. The respondents completed measures of trust, attitudes toward women, hostility, self-esteem, and father involvement. Nontraditional gender role attitudes, positive ratings of their own interpersonal trust, and low hostility toward men were predictive of the respondents' support for father involvement. Participant demographics (including age, marital status, and number of children) were unrelated to their views of father involvement. Results indicate the importance of considering the characteristics and attitudes women bring to the co-parental relationship in the examination of factors influencing father involvement with children. Findings are discussed within the context of mothers' primary child-care and gatekeeping roles.

Can Medicare survive its saviors?

It is now an open question whether Medicare will provide adequate health coverage to the baby-boom generation as it begins turning 65 just over a decade from now. The source of uncertainty is not whether America has the resources to sustain the program; we do. The real challenge comes instead from proposals to save Medicare. Far from preserving its benefits, the major restructuring proposals under discussion would radically alter the principles on which Medicare rests and erode the protection it affords.

Does sufentanil concentration influence isoflurane requirements during coronary artery bypass grafting?

OBJECTIVE

To search for concentration-related suppression of hemodynamic responsiveness by sufentanil.

DESIGN

Prospective, randomized, double-blind study.

SETTING

University hospital.

PARTICIPANTS

Patients undergoing elective coronary artery bypass grafting (CABG).

INTERVENTION

Patients were assigned to target effect-site sufentanil concentrations of 1.5 ng/mL (group L; n = 14), 3.0 ng/mL (group M; n = 13), or 4.5 ng/mL (group H; n = 12). Sufentanil was administered by computer-assisted continuous infusion. Isoflurane was used to maintain intraoperative hemodynamics near preoperative values.

MEASUREMENTS AND MAIN RESULTS

Hemodynamics, the electroencephalographic spectral edge (SE95), and end-tidal isoflurane concentration (ET-ISO) were measured every 10 to 30 seconds during the prebypass period. Serum sufentanil concentration was measured at intervals. Prebypass serum sufentanil concentrations were stable, averaging 3.0 +/- 0.7, 5.1 +/- 1.1, and 7.1 +/- 1.3 ng/mL in groups L, M, and H, respectively. The groups did not differ with respect to the speed of induction, intraoperative hemodynamics, incidence of isoflurane use, or isoflurane concentrations required. ET-ISO and serum sufentanil levels were not correlated. Among seven group L patients who did not require isoflurane, the average prebypass serum sufentanil concentration ranged from 1.7 to 3.3 ng/mL.

CONCLUSION

Sufentanil does not induce concentration-related suppression of hemodynamic responsiveness over the range studied. A stable serum sufentanil concentration of 3.0 +/- 0.7 ng/mL induces the maximal opioid effect and need not be exceeded in patients undergoing CABG. A sufentanil concentration of 1.7 ng/mL provides clinically adequate anesthesia without supplementation in some premedicated patients undergoing CABG.

State-level variation in Medicare spending

Theoretically, Medicare provides one standard benefit package to all enrollees. But because of State-level variations in populations, service supply, and local practice patterns, national policy changes may have unequal impacts on access and service utilization. Across-the-board policy changes may create hardships in one area while appropriately discouraging use in another area. In this article, the authors describe State-level variations in Medicare enrollees, their insurance coverage, 1995 Medicare and beneficiary spending patterns in aggregate, per capita, and by service, and certain spending patterns for dually eligible beneficiaries. These data are useful for considering the State-level effects of payment reform.

Will the care be there? Vulnerable beneficiaries and Medicare reform

The Medicare program is on the verge of major change. The proof of the value of reforms will not rest in how well the program meets the needs of the healthy and wealthy, but rather in whether they preserve or improve upon protections for those who would not be well served by an unregulated private sector--persons with low incomes and/or substantial health problems. This paper examines four key issues: Which beneficiaries will likely be best served by a system oriented around choice; what role traditional Medicare should continue to play and what changes will be needed; what protections are necessary for persons with low and moderate incomes; and how these reforms could be incorporated into broader changes to make Medicare more viable over time.

Options for aiding low-income Medicare beneficiaries

This paper examines the effectiveness of the Qualified Medicare Beneficiary (QMB), Specified Low-Income Medicare Beneficiary (SLMB), and Qualified Individual (QI) programs that seek to ease the financial burdens of health costs on low-income Medicare beneficiaries. While participation in these programs has been increasing steadily over time, much remains to be done to extend benefits to all those currently eligible. This paper estimates levels of participation in the existing programs and considers several scenarios under which participation could be increased further, including federalizing the existing programs, raising or eliminating asset limits, and raising income ceilings.