A comparison of mutation rates for specific loci and chromosome regions in dysgenic hybrid males of Drosophila melanogaster.

The mutation rates of specific loci and chromosome regions were estimated for two types of dysgenic hybrid males. These came from crosses between P or Q males and M females in the P-M system of hybrid dysgenesis. The M X P hybrids were the more mutable for each of the loci and chromosome regions tested. The Beadex locus was highly mutable in these hybrids but did not mutate at all in the sample of gametes from the M X Q hybrids. The singed locus had 75% of the mutability of Beadex in the M X P hybrids; it was also mutable in the M X Q hybrids. The white locus was only slightly mutable in the M X P hybrids and not at all mutable in the M X Q hybrids. The mutations in singed and white probably arose from the insertion of P elements into these loci; the mutations at Beadex probably involved the action of a P element located near this locus on the X chromosome of the P strain that was used in the experiments. Mutations in two chromosome regions, one including the zeste-white loci and the other near the miniature locus, were much more frequent in the M X P hybrids than in the M X Q hybrids. These mutations also probably arose from P element insertions. The implication is that insertion mutations occur infrequently in the M X Q hybrids, possibly because most of the P elements they carry are defective. In M X P hybrids, there is variation among loci with respect to P element mutagenesis, indicating that P elements possess a degree of insertional specificity.

High mutability in male hybrids of Drosophila melanogaster.

The frequencies of sex-linked lethal mutations arising in hybrid male offspring from crosses and in nonhybrid controls were determined. The hybrids were produced by crossing representative strains of the P-M system of hybrid dysgenesis in all possible combinations. Males from the cross of P males x M females had a mutation rate about 15 times higher than that of nonhybrid males from the P strain. Genetically identical males from the reciprocal cross had a mutation rate 3 to 4 times that of the nonhybrids. For crosses involving a Q strain, a significant increase in the mutation rate was detected in males produced by matings of Q males with M females. No increase was observed in genetically identical males from the reciprocal mating. Crosses between P and Q strains gave male hybrids with mutation rates not different from those of nonhybrids. Many of the lethals that occurred in hybrids from the cross of P males x M females appeared to be unstable; fewer lethals that arose in hybrids from the cross of Q males x M females were unstable. The relationship between P and Q strains is discussed with respect to a model of mutation induction in dysgenic hybrids.

Primary care program improves reimbursement. The Federally Qualified Health Center program helps hospitals improve services to the medically indigent.

Under a program created by Congress in 1989, certain primary care treatment centers serving the medically and economically indigent can become Federally Qualified Health Centers (FQHCs). Recently enacted rules and regulations allow participants in the FQHC program to receive 100 percent reasonable cost reimbursement for Medicaid services and 80 percent for Medicare services. An all-inclusive annual cost report is the basis for determining reimbursement rates. The report factors in such expenses as physician and other healthcare and professional salaries and benefits, medical supplies, certain equipment depreciation, and overhead for facility and administrative costs. Both Medicaid and Medicare reimbursement is based on an encounter rate, and states employ various methodologies to determine the reimbursement level. In Illinois, for example, typical reimbursement for a qualified encounter ranges from $70 to $88. To obtain FQHC status, an organization must demonstrate community need, deliver the appropriate range of healthcare services, satisfy management and finance requirements, and function under a community-based governing board. In addition, an FQHC must provide primary healthcare by physicians and (where appropriate) midlevel practitioners; it must also offer its community diagnostic laboratory and x-ray services, preventive healthcare and dental care, case management, pharmacy services, and arrangements for emergency services. Because FQHCs must be freestanding facilities, establishing them can trigger a number of ancillary legal issues, such as those involved in forming a new corporation, complying with not-for-profit corporation regulations, applying for tax-exempt status, and applying for various property and sales tax exemptions. Hospitals that establish FQHCs must also be prepared to relinquish direct control over the delivery of primary care services.

Update on emergency department staffing requirements.

This article outlines the various legal responsibilities attendant to a hospital's provision of emergency medical services. Specifically, the article focuses on various issues relating to emergency department staffing, including the hospital's duty to provide emergency medical services and the liability of various parties for patient injuries sustained during the course of emergency treatment.