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Biomedical subjects

C E Bishop

Publications and source records attributed to C E Bishop.

At least 55 records · Page 3Linked to original sources
PubMed1994

Do preset per visit payment rates affect home health agency behavior?

This article reports on preliminary impacts during the first year of a demonstration in which home health agencies (HHAs) were paid a prospectively set rate for each Medicare home health visit rendered, rather than being reimbursed for costs. Forty-seven agencies in five States participated. The evaluation compared the experiences of randomly assigned treatment agencies and their patients with those of control agencies and their patients and found no compelling evidence of any demonstration impact on agency cost per visit, the volume of home health services, agency revenue and profit, patient selection and retention, quality of care, or use and cost of Medicare services.

Costs and Cost Analysis↗
PubMed1993

Deletion of Y chromosome sequences located outside the testis determining region can cause XY female sex reversal.

An approach designed to map and generate mutations in the region of the short arm of the mouse Y chromosome, known to be involved in sex determination and spermatogenesis, is described. This relies on homologous Yp-Sxra pairing and asymmetrical exchange which can occur at meiosis in XY males carrying Sxra on their X chromosome. Such exchange potentially generates deficiencies and duplications of Yp or Sxra. Three fertile XY females were found out of about 450 XY offspring from XSxra/Y x XX crosses. In all three, despite evidence for deletion of Y chromosomal material, the Sry locus was intact. Each deletion involved a repeat sequence, Sx1, located at a distance from Sry. Since expression of Sry was affected these results suggest that long range position effects have disrupted Sry action.

Animals↗
PubMed1992

Marsupial Y chromosome encodes a homologue of the mouse Y-linked candidate spermatogenesis gene Ube1y.

The mammalian subclass Theria consists of infraclasses Metatheria (marsupials) and Eutheria ('placentals') which diverged from each other 120-150 million years before present (Myr BP). Both infraclasses have Y chromosome-dependent testis determination but direct molecular evidence linking the Metatherian and Eutherian Y chromosomes is lacking. Comparative analyses indicate that three mammalian genes have remained Y-linked for at least 80 Myr, since the divergence of the Eutherian orders from a common ancestor. These are Zfy, a gene encoding a transcription factor of the zinc-finger type; Sry, the putative primary testis-determining gene; and Ube1y (formerly Sby or A1s9Y-1), a candidate for the mouse spermatogenesis gene Spy, encoding a ubiquitin-activating enzyme E1 homologue. Although in marspials Zfy homologues are autosomal, a Y homologue of Sry has recently been isolated. We report here the identification of a functional marsupial Y-linked homologue of the murine Ube1y gene establishing that Metatherian and Eutherian Y chromosomes diverged from a common ancestor. This extreme conservation indicates that Ube1y plays a critical role in male development.

Amino Acid Sequence↗
PubMed1992

Mutations in the conserved domain of SRY are uncommon in XY gonadal dysgenesis.

In order to evaluate the role of SRY in the determination of the testis, we sequenced the conserved domain of the SRY gene in 8 patients with 46,XY gonadal dysgenesis and 3 patients with related disorders, and compared our data with those obtained in 6 other similar studies. In our study, a 609-bp fragment of SRY was amplified by the polymerase chain reaction and the internal conserved motif was sequenced. SRY sequences did not differ from those in normal males in any of our patients. Overall, 5 de novo mutations have been identified among 56 patients with sporadic XY gonadal dysgenesis (8.9%), and 2 de novo mutations have been identified among 18 patients with related conditions (11%). The unexpectedly low frequency of mutations within the SRY conserved domain in these patients could be caused by undetected Y-linked mutations outside the conserved domain in regions that control transcription during development (e.g., promoter/enhancer regions) or to downstream mutations in other sex-determining genes that need not map to the Y.

Adolescent↗
PubMed1992

A structural analysis of the Sxr region of the mouse Y chromosome.

Three genetic functions have been mapped to the minute Sxr (sex-reversed) region of the mouse Y chromosome. These are Tdy, the primary testis determinant; Hya, the locus (either structural or regulatory) controlling the expression of the male-specific minor histocompatibility antigen H-Y; and Spy, a spermatogenic gene. Hya and Spy map to DNA deleted from the Sxr region in the deletion variant Sxrb (the delta Sxrb DNA). With the object of cloning Hya and Spy, we initiated chromosome walking in the delta Sxrb DNA. From three independent loci--Sx1, Zf2, and T5--we have isolated approximately 270 kb of delta Sxrb DNA lying in three contigs of 145, 60, and 65 kb, respectively. Within 17 kb of the 3' end of the Zfy-2 gene, lowcopy repeat elements were found in a region that extends for approximately 35 kb. Probes isolated from this region detect multiple Sxr loci, some of which map to the delta Sxrb DNA present in the T5 contig DNA. Three of these multicopy probes detect delta Sxrb loci not represented in our three contigs, which means that six distinct delta Sxrb loci have now been identified. Here we present a preliminary model of the molecular structure of the DNA in this unique region.

Animals↗
PubMed1992

Recombination between the X and Y chromosomes and the Sxr region of the mouse.

The Sxr (sex-reversed) region that carries a copy of the mouse Y chromosomal testis-determining gene can be attached to the distal end of either the Y or the X chromosome. During male meiosis, Sxr recombined freely between the X and Y chromosomes, with an estimated recombination frequency not significantly different from 50% in either direction. During female meiosis, Sxr recombined freely between the X chromosome to which it was attached and an X-autosome translocation. A male mouse carrying the original Sxra region on its Y chromosome, and the shorter Sxrb variant on the X, also showed 50% recombination between the sex chromosomes. Evidence of unequal crossing-over between the two Sxr regions was obtained: using five markers deleted from Sxrb, 3 variant Sxr regions were detected in 159 progeny (1.9%). Four other variants (one from the original cross and three from later generations) were presumed to have been derived from illegitimate pairing and crossing-over between Sxrb and the homologous region on the short arm of the Y chromosome. The generation of new variants throws light on the arrangement of gene loci and other markers within the short arm of the mouse Y chromosome.

Animals↗
PubMed1991

Homology of a candidate spermatogenic gene from the mouse Y chromosome to the ubiquitin-activating enzyme E1.

The Sxr (sex-reversed) region, a fragment of the Y chromosome short arm, can cause chromosomally female XXSxr or XSxrO mice to develop as sterile males. The original Sxr region, termed Sxra, encodes: Tdy, the primary sex-determining gene; Hya, the controlling or structural locus for the minor transplantation antigen H-Y; gene(s) controlling the expression of the serologically detected male antigen (SDMA); Spy, a gene(s) required for the survival and proliferation of A spermatogonia during spermatogenesis; Zfy-1/Zfy-2, zinc-finger-containing genes of unknown function; and Sry, which is probably identical to Tdy. A deletion variant of Sxra, termed Sxrb, which lacks Hya, SDMA expression, Spy and some Zfy-2 sequences, makes positional cloning of these genes possible. We report here the isolation of a new testis-specific gene, Sby, mapping to the DNA deleted from the Sxrb region (the delta Sxrb interval). Sby has extensive homology to the X-linked human ubiquitin-activating enzyme E1. The critical role of this enzyme in nuclear DNA replication together with the testis-specific expression of Sby suggests Sby as a candidate for the spermatogenic gene Spy.

Amino Acid Sequence↗
PubMed1991

Living with others as an alternative to nursing home use.

The authors studied a synthetic sample combining information on nonmarried women from surveys of community-resident elderly and nursing home residents to identify factors affecting the probability of observing individuals in one of three situations: living alone, living with others, and residing in a nursing home. Increasing income increased slightly the probability of living alone and had a positive effect on the probability of residing in a nursing home for most income levels within the sample range. As expected, disability and increasing age were very important in distinguishing those in the nursing home from those residing in the community, and also increased the probability of living with others, other things remaining constant. Whites were slightly more likely to live alone and less likely to reside in a nursing home, other things remaining constant. Residing in a warmer climate decreased the probability of being a nursing home resident. The analysis indicates that factors distinguishing nursing home residents from community residents are also at least somewhat useful in distinguishing those who live alone from those who live with others, supporting the inclusion of shared community living arrangements with the nursing home as part of a continuum of supportive living arrangements.

Activities of Daily Living↗
PubMed1991

Medicare patient access to posthospital skilled nursing facility care.

The willingness of nursing homes to accept any Medicare admissions (Medicare participation) and the number of patients they serve (Medicare utilization) affect the access of Medicare SNF patients to posthospital care. Characteristics of facilities, their market areas, and state Medicaid reimbursement were found to affect both participation and utilization. Most important, when Medicaid and private nursing home market conditions support high-intensity care, facilities are more likely to serve Medicare patients and admit more of them. SNFs in states that require Medicare certification are more likely to accept Medicare admissions, suggesting that the cost and effort of achieving certification are a barrier to service to Medicare SNF patients. For-profit facilities, hospital-based SNFs, and larger nursing homes have higher rates of participation and serve more Medicare patients when they serve any.

Costs and Cost Analysis↗
PubMed1989

Evidence for distinguishable transcripts of the putative testis determining gene (ZFY) and mapping of homologous cDNA sequences to chromosomes X,Y and 9.

Oligonucleotide sequences based on the amino acid sequence of the putative testis determining gene ZFY have been used to isolate a 1.3 Kb Hind III Y genomic DNA fragment CMPXY1 and three human testis cDNA sequences (CMPXY2, CMPXY3 and CMPXY4). These sequences detect at least four potential exons on the Y (Y1, Y3, Y4 and Y5), three on the X (X1, X2 and X3) and three of autosomal origin (A1, A2 and A3) as determined by comparing the fragments detected by different clones. Analysis with subfragments of CMPXY4 shows that Y3 is unique to the Y and that Y4 and X1 are homologous. Y5 and X3 are detected by the same subfragment of CMPXY4. This is also the case for Y1, X2, A1, A2 and A3. Thus these exons may contain further regions of homology between the X, Y and an autosomal locus. The X-linked sequences all lie in Xp21.2-Xp22.1 and studies with XX males have placed the Y-linked sequences in distal Yp adjacent to the Y-autosomal homologous sequence GMGY3. We have confirmed these localizations by in situ hybridization with CMPXY4 and have shown additionally that the autosomal sequences of both the CMPXY4 sequence and GMGY3 map to 9p22-9pter. Restriction analysis demonstrates that CMPXY1/XY2/XY3 differ in sequence from CMPXY4 at three restriction enzyme sites, thus suggesting that they are transcribed from different but closely related genes and that CMPXY4 must be either X-linked or autosomal in origin. This indicates that more than one of the loci containing ZFY-related sequences are transcribed and potentially fulfil functionally distinct roles in the human sex determining pathway. Northern blot analysis of human foetal testis RNA has shown that three low abundance transcripts of 5, 6 and 8 Kb can be detected by ZFY-related DNA sequences.

Base Sequence↗
PubMed1989

Patterns of nursing home use in a prepaid managed care system: the continuing care retirement community.

The use of nursing home services among 3,316 residents of six continuing care retirement communities (CCRCs) was compared with that of the general elderly population. CCRC residents have a greater lifetime risk of nursing home entry and repeat entries. CCRC resident's length of stay per admission, however, is shorter. Findings from this comparative analysis provided insight into nursing home use in an insured and managed long term care program for a closed population.

Aged↗
PubMed1989

The composition of home health care expenditure growth.

During the period 1980 to 1985, growth in the number of persons served by Medicare home health was the largest source of growth in Medicare home health expenditures. Population growth was in part responsible for the increase in beneficiaries using Medicare home health, but more important was growth in the number of persons served per 1000 elderly population. Cost per person served increased only moderately once input price changes are accounted for. Nevertheless, we recommend that cost-containment efforts focus on cost per visit and per case, because restrictions on persons served are likely to limit Medicare beneficiaries' access to needed, covered care.

Centers for Medicare and Medicaid Services, U.S.↗
PubMed1988

Molecular aspects of sex determination in mice: an alternative model for the origin of the Sxr region.

Using a combination of in situ mapping and DNA analysis with recombinant DNA probes specific for the Sxr region of the mouse Y chromosome, we show that both the gene(s) controlling primary sex determination and the expression of the male-specific antigen H-Y (Tdy and Hya respectively) are located on the minute short arm of the mouse Y chromosome. We demonstrate that the H-Y- variant of Sxr (Sxr') arose by a partial deletion within the Sxr region and propose an alternative model for the generation of the original Sxr region.

Animals↗
PubMed1988

Molecular and cytogenetic evidence for the location of Tdy and Hya on the mouse Y chromosome short arm.

Using a combination of in situ mapping and DNA analysis with recombinant DNA probes specific for the Sxr region of the mouse Y chromosome, we show that both the gene(s) controlling sex determination and the expression of the male-specific antigen H-Y (Tdy and Hya, respectively) are located on the minute short arm of the mouse Y chromosome. We demonstrate that the H-Y- variant of Sxr (Sxr') arose by a partial deletion within the Sxr region. Also, we show that intrachromosomal recombination between the Y short arm and Sxr' can sometimes occur during male meiosis, restoring the deleted DNA sequences and resulting in an H-Y+ mouse (male 719 in this paper). Based on these results, we propose a model for the generation of the original Sxr region and the Sxr' and Sxr719 variants.

Animals↗
PubMed1988

Competition in the market for nursing home care.

The competitive model may fit the nursing home sector better than it fits other health care markets, but Medicaid subsidies and regulation have not allowed the market to work freely, and nursing home insurance may cause further divergence from a competitive ideal. Incentives for both providers and consumers that capitalize on competitive aspects of the market might be used to improve outcomes of the nursing home market, especially under a system of comprehensive long-term care insurance.

Consumer Advocacy↗