Organization of human and mouse skeletal myosin heavy chain gene clusters is highly conserved

Myosin heavy chains (MyHCs) are highly conserved ubiquitous actin-based motor proteins that drive a wide range of motile processes in eukaryotic cells. MyHC isoforms expressed in skeletal muscles are encoded by a multigene family that is clustered on syntenic regions of human and mouse chromosomes 17 and 11, respectively. In an effort to gain a better understanding of the genomic organization of the skeletal MyHC genes and its effects on the regulation, function, and molecular genetics of this multigene family, we have constructed high-resolution physical maps of both human and mouse loci using PCR-based marker content mapping of P1-artificial chromosome clones. Genes encoding six MyHC isoforms have been mapped with respect to their linear order and transcriptional orientations within a 350-kb region in both human and mouse. These maps reveal that the order, transcriptional orientation, and relative intergenic distances of these genes are remarkably conserved between these species. Unlike many clustered gene families, this order does not reflect the known temporal expression patterns of these genes. However, the conservation of gene organization since the estimated divergence of these species (approximately 75-110 million years ago) suggests that the physical organization of these genes may be significant for their regulation and function.

Liminality: a major category of the experience of cancer illness

Narrative analysis is well established as a means of examining the subjective experience of those who suffer chronic illness and cancer. In a study of perceptions of the outcomes of treatment of cancer of the colon, we have been struck by the consistency with which patients record three particular observations of their subjective experience: (1) the immediate impact of the cancer diagnosis and a persisting identification as a cancer patient, regardless of the time since treatment and of the presence or absence of persistent or recurrent disease; (2) a state of variable alienation from social familiars, expressed as an inability to communicate the nature of the experience of the illness, its diagnosis and treatment; and (3) a persistent sense of boundedness, an awareness of limits to space, empowerment and available time. These subjectivities were experienced in varying degree by all patients in our study. Individual responses to these experiences were complex and variable. The experiences are best understood under the rubric of a category we call "liminality". We believe that all cancer patients enter and experience liminality as a process which begins with the first manifestations of their malignancy. An initial acute phase of liminality is marked by disorientation, a sense of loss and of loss of control, and a sense of uncertainty. An adaptive, enduring phase of suspended liminality supervenes, in which each patient constructs and reconstructs meaning for their experience by means of narrative. This phase persists, probably for the rest of the cancer patient's life. The experience of liminality is firmly grounded in the changing and experiencing body that houses both the disease and the self. Insights into the nature of the experience can be gained from the Existentialist philosophers and from the history of attitudes to death. Understanding liminality helps us to understand what it is that patients with cancer (and other serious illnesses) seek from the system to which they turn for help. Its explication should therefore be important for those who provide health care, those who educate health care workers and those concerned to study and use outcomes as administrative and policy making instruments.

A national center for biocomputation: in search of a patient-specific interactive virtual surgery workbench

This report describes the three-dimensional imaging and virtual environment technologies developed in NASA's Biocomputation Center for scientific purposes that have now led to applications in the field of medicine. A major goal is to develop a virtual environment surgery workbench for planning complex craniofacial and breast reconstructive surgery, and for training surgeons.

Study of aeroball injuries

OBJECTIVE

To present the risks of aeroball, a new sport played by either two or four players on a trampoline court surrounded by specially constructed fabric walls, and to propose ways to increase awareness and reduce the incidence of injury, in particular, ankle injury.

METHOD

A study was carried out to document the nature of aeroball related incidents, between 1991 and 1995, at Lancaster University Sports Centre. Lace-up ankle supports were introduced in April 1992, and their effect on the incidence of ankle injury was recorded.

RESULTS

The lower limb received most injuries (90%), followed by the upper limb (6%), then the face (3%) and cervical spine (1%). The most common category of injuries was sprains (83%), followed by fractures (8%), contusions (5%), and dislocations (4%). The most common site of injury was the ankle (73%). It is during doubles play that injury is most likely to occur. Since the introduction of ankle supports, there has been a gradual decline in the incidence of ankle injury, 31 in 1991 to nine in 1995.

CONCLUSION

Aeroball has become a popular sport, but it is not without risks. Leaflets have been produced to promote the objectives, rules, and safety of the game. Trained full-time staff should be present to explain the nature of the game. The use of prophylactic ankle stabilisers in aeroball is strongly recommended.

Assisted suicide: implications for nurses and nursing

Assisted suicide is an issue of great importance to nurses. This issue reflects our values and beliefs as a society, calls for a clear and precise response as a profession, and challenges individual nurses to think about their own moral views. The history of the debate and the compelling moral arguments on both sides attest to the complexity of the issue and also suggest that it will not soon be resolved. The current position of the profession, as expressed in the ANA Code for Nurses and a specific position statement, were reviewed. The dilemma faced by the individual nurse who perceives an obligation to adhere to the guidelines specified by his or her profession's code and yet whose conscience dictates an act in violation of this code has been discussed as an instance of conscientious objection. While this analysis has been necessarily brief, it was intended to illustrate the importance of being clear about one's personal moral views and equally clear about one's duty to fulfil the obligations stemming from the profession's public statements. It is essential that the profession continue to explore the moral issues involved in requests for assistance in dying and provide additional guidelines for practicing nurses, with sound rationale for the profession's position.

cDNA cloning, tissue distribution, and chromosomal localization of myelodysplasia/myeloid leukemia factor 2 (MLF2)

A fusion gene between nucleophosmin (NPM) and myelodysplasia/myeloid leukemia factor 1 (MLF1) is formed by a recurrent t(3;5)(q25.1;q34) in myelodysplastic syndrome and acute myeloid leukemia. Here we report the identification of a novel gene, MLF2, which contains an open reading frame of 744 bp encoding a 248-amino-acid protein highly related to the previously identified MLF1 protein (63% similarity, 40% identity). In contrast to the tissue-restricted expression pattern of MLF1, the MLF2 messenger RNA is expressed ubiquitously. The MLF2 gene locus was mapped by fluorescence in situ hybridization to human chromosome 12p13, a chromosomal region frequently involved in translocations and deletions in acute leukemias of lymphoid or myeloid lineage. In a physical map of chromosome 12, MLF2 was found to reside on the yeast artificial chromosome clone 765b9. Southern blotting analysis of malignant cell DNAs prepared from a series of acute lymphoblastic leukemia cases with translocations involving chromosome arm 12p, as well as a group of acute myeloid leukemias with various cytogenetic abnormalities, failed to reveal MLF2 gene rearrangements.

A network approach to outpatient service delivery systems: resources flow and system influence

OBJECTIVE

The study tests a path model for the effects on organizational influence of an organization's centrality in four resource exchange networks in order to gain insight into the network relations that may affect coordination and effectiveness of outpatient health and mental health service systems.

DATA SOURCES

Primary data are used from face-to-face interviews with the directors of every organization in the predefined service systems in three urbanized counties in Oregon. Each system consisted of 19 to 20 organizations. Data were collected during 1986 and 1987.

STUDY DESIGN

The path model contains five variables: the major dependent variable is attributed organizational influence; the independent variables are three sets of primary resource exchanges: funds allocation, client referrals, and client inflow. An intervening variable of general network contacts, as an informational resource, is modeled as an outcome of the three primary resource exchanges, as well as one of the predictors of influence.

DATA COLLECTION

Organizations were identified as system members through a modified snowball sampling procedure. Measures of organizational influence and centrality in each of the exchange networks were derived from interviews with all directors about their interactions with each organization in the system. Multiple regression analysis was used to test the path model.

PRINCIPAL FINDINGS

The most important resource in predicting centrality in a general contact network is centrality in a client referral network, while contacts and funds allocation centrality are significant predictors of organizational influence.

CONCLUSIONS

The organization with the greatest influence within the system (because of its ability to allocate funds) may not be the organization that takes the largest role in terms of coordinating routine contacts (because of its ability to refer clients). This disjuncture may signal a weakness in the coordination network and system effectiveness, since the more influential organization may not be the most knowledgeable one in terms of the needs of the system.

CONTIG EXPLORER: interactive marker-content map assembly

In STS-content mapping of a region, multiple optimal or near-optimal putative orders of markers exist. Determining which of the markers in this region can be placed reliably on the physical map of the chromosome and which markers lack sufficient evidence to be placed requires software that facilitates exploratory sensitivity analysis and interactive reassembly with different subsets of the imput data and that also assists the evaluation of any arbitrary (user-specified) marker order. We describe CONTIG EXPLORER, a package for interactive assembly of STS-content maps that provides the user with various ways of performing such analyses, thereby facilitating the design of laboratory experiments aimed at reducing ambiguity in STS order. We then compare the output of CONTIG EXPLORER with two other assembly programs, SEGMAP and CONTIGMAKER, for a region of chromosome 12p between 21 and 38 cM on the sex-averaged CEPH/Généthon linkage map.

A second-generation YAC contig map of human chromosome 12

Human chromosome 12 constitutes approximately 4.5% of the human genome and has an estimated size of 135 million base pairs (Mb). We have started to construct a high-resolution physical map of chromosome 12 as overlapping yeast artificial chromosomes (YACs), using as a foundation the first-generation physical map of this chromosome covers nearly 102 Mb of DNA and includes 426 highly polymorphic, monomorphic and gene-based markers. We also mapped 119 of the YACs, most of which are part of the physical map, by cytogenetic methods. Thus the map integrates genetic, physical and cytogenetic data and provides information about the organization of this chromosome and will help in the localization and cloning of disease-related genes. The strategy used here to generate the chromosome-12 map could be applied for the rapid construction of physical and expression maps for other human chromosomes.

Unequal homologous recombination of human DNA on a yeast artificial chromosome

We examined unequal homologous DNA recombination between human repetitive DNA elements located on a yeast artificial chromosome (YAC) and transforming plasmid molecules. A plasmid vector containing an Alu element, as well as a sequence identical to a unique site on a YAC, was introduced into yeast and double recombinant clones analyzed. Recombination occurs between vector and YAC Alu elements sharing as little as 74% identity. The physical proximity of an Alu element to the unique DNA segment appears to play a significant role in determining the frequency with which that element serves as a recombination substrate. In addition, cross-over points of the recombination reaction are largely confined to the ends of the repetitive element. Since a similar distribution of crossover sites occurs during unequal homologous recombination in human germ and somatic tissue, we propose that similar enzymatic processes may be responsible for the events observed in our system and in human cells. This suggests that further examination of the enzymology of unequal homologous recombination of human DNA within yeast may yield a greater understanding of the molecular events which control this process in higher eukaryotes.

p27Kip1: chromosomal mapping to 12p12-12p13.1 and absence of mutations in human tumors

The p27Kip1 gene codes for a cyclin-dependent kinase inhibitor implicated in G1 arrest by transforming growth factor beta, cell-cell contact, agents that elevate cyclic AMP, and the growth-inhibitory drug rapamycin. p27 binds to and inhibits complexes formed by cyclin E-cdk2, cyclin A-cdk2, and cyclin D-cdk4. The involvement of p27 in the negative regulation of cell proliferation suggests that it may also function as a tumor suppressor gene. Using a combination of somatic cell hybrid panels and fluorescence in situ hybridization p27Kip1 has been mapped to the short arm of chromosome 12 at the 12p12-12p13.1 boundary, reported to harbor deletions and rearrangements in leukemia and mesotheliomas. In order to assess potential p27Kip1 gene alterations, we have screened a total of 147 human primary solid tumors and found no detectable cancer-specific mutations. These results argue that the often observed loss of antimitogenic transforming growth factor beta responsiveness in human cancer cells is not due to structural defects in p27Kip1.

Internet-based support for bioscience research: a collaborative genome center for human chromosome 12

This paper describes an approach that provides Internet-based support for a genome center to map human chromosome 12, as a collaboration between laboratories at the Albert Einstein College of Medicine in Bronx, New York, and the Yale University School of Medicine in New Haven, Connecticut. Informatics is well established as an important enabling technology within the genome mapping community. The goal of this paper is to use the chromosome 12 project as a case study to introduce a medical informatics audience to certain issues involved in genome informatics and in the Internet-based support of collaborative bioscience research. Central to the approach described is a shared database (DB/12) with Macintosh clients in the participating laboratories running the 4th Dimension database program as a user-friendly front end, and a Sun SPARCstation-2 server running Sybase. The central component of the database stores information about yeast artificial chromosomes (YACs), each containing a segment of human DNA from chromosome 12 to which genome markers have been mapped, such that an overlapping set of YACs (called a "contig") can be identified, along with an ordering of the markers. The approach also includes 1) a map assembly tool developed to help biologists interpret their data, proposing a ranked set of candidate maps, 2) the integration of DB/12 with external databases and tools, and 3) the dissemination of the results. This paper discusses several of the lessons learned that apply to many other areas of bioscience, and the potential role for the field of medical informatics in helping to provide such support.

Mapping of the 12q12-q22 region with respect to tumor translocation breakpoints

The consistent involvement of the region 12q13-q15 in numerous human tumors speaks in favor of the presence of genes that may contribute to oncogenesis. Mapping genes within this region of chromosome 12 is a necessary step toward the identification of those that play a role in this process. We have undertaken a multiplex analysis using translocation breakpoint mapping to order from the centromere to the telomere a series of 24 loci from the region 12q12-q22. Thirteen adipose tissue tumors with seven different chromosome changes involving the long arm of chromosome 12 (12q) were used. Since most of these loci are genes or anonymous DNA segments largely available to the scientific community, this map should be useful for investigation of genetic disorders associated with chromosome 12q. While these breakpoints were used as natural landmarks to order groups of loci, this work has positioned them more accurately, leading to a better chromosomal definition of the translocations than the one derived from standard cytogenetic studies.

Primary care physicians' refusal to care for patients infected with the human immunodeficiency virus

We conducted a telephone survey of a random sample of office-based primary care physicians in Los Angeles County to determine their practice experiences with patients infected with the human immunodeficiency virus (HIV). Telephone interviews included questions related to the physicians' experiences evaluating patients for HIV infection during the past 6 months and the presence of HIV-infected patients in their practices. Those without HIV-infected patients were asked if this was because they had not encountered such patients, because those patients had died, or because the physicians had chosen to refer these patients elsewhere or the patients had gone elsewhere for care. Of physicians who participated in the survey, 78% had evaluated a patient for HIV infection in the past 6 months; 34% were currently providing primary care for infected patients; and 36% had elected to refer HIV-infected patients elsewhere, or their patients had elected to find other physicians. In all, 48% of physicians in the sample had elected not to care for, or said they would not provide care for, patients with HIV infection. Among Los Angeles County primary care physicians, 36% have refused to provide continuing care for HIV-infected patients and another 12% indicated their unwillingness to do so should such patients present themselves for care. As of 1991, the reservoir of primary care physicians in Los Angeles not yet involved with but willing to care for HIV-infected patients is relatively small (15%).

Telephone screening for risk of HIV infection

This study responds to a Centers for Disease Control request to develop innovative case-finding methods and asks two questions: 1) Will men participate in an anonymous telephone interview containing detailed questions about their sexual practices to enable screening for HIV-related risk? 2) Will individuals told they are at increased risk follow up by calling a toll-free number for additional AIDS information, counseling, or medical evaluation? Random-digit-dialed interviews were completed with 1610 adult men in Los Angeles County; the completion rate among eligible men was 68.3%. Nearly 43% of men were assessed at increased risk, half of whom described behaviors that placed them only at moderate risk and half of whom reported behaviors placing them at higher risk. Although the study found men were willing to provide personal risk-assessment information, only 14 of 343 men were willing to initiate a follow-up telephone call to the project counselors as the next step in case-finding.

Responses to AIDS: large urban and small rural hospitals

This study examines the assumptions that large urban hospitals will differ strikingly from small rural hospitals in their experience with AIDS patients, the staff-related problems caused by AIDS patients, and the administrative actions undertaken by the hospital in response. Results from a national stratified random sample of U.S. hospitals showed that by mid-1989 nearly all large urban hospitals had admitted AIDS patients, while only one-quarter of small rural hospitals had done so. Yet, over three-quarters of small rural hospitals have already adopted administrative policies about HIV testing of patients, and the contents of such policies differ little from those adopted by large urban hospitals. Despite similarity in official administrative responses, attitudinal differences exist. Staff fears of contagion and attitudes about isolation of HIV-positive patients are more evident in small rural hospitals; yet, recruitment difficulties triggered by staff concerns are greater in large urban hospitals.

The HIV-testing policies of US hospitals

To determine the human immunodeficiency virus-testing policies adopted by US hospitals, we surveyed a stratified random sample of all nonfederal general acute care hospitals, drawn from the American Hospital Association's 1987 database. Interviews were completed with the chief administrator in 561 hospitals (response rate, 78.4%). Two thirds of hospitals have admitted at least one patient with the acquired immunodeficiency syndrome, and over 83% have formal written policies about human immunodeficiency virus testing. Most contain provisions protecting patients' rights; eg, 78% require pretest informed consent, 66% require a special human immunodeficiency virus-testing consent form, and 75% require that patients who test seropositive be so informed. Many policies also contain provisions that protect providers; eg, 56% require that test results appear in patients' records, 38% require review of treatment plans when a patient tests seropositive, and 3% require transferring such patients. Hospital characteristics are not strongly associated with the adoption of testing policies.

The AIDS-related experiences and practices of primary care physicians in Los Angeles: 1984-89

Telephone interviews of random samples of Los Angeles primary care physicians in 1984, 1986, and 1989 obtained information about their AIDS-related practice experiences, and sexual history taking. Data from mid-1989 reveal almost 74 percent have worked up at least one patient for AIDS or HIV infection in the past six months and 39.5 percent are caring for at least one patient with AIDS or AIDS-related complex. Self-reported use of appropriate sexual history questions has improved substantially over this five-year period.

In vitro phosphorylation of tropomyosin by a kinase from chicken embryo

A tropomyosin kinase has been partially purified from the leg muscle of 11-day-old chick embryos by ammonium sulfate precipitation and DEAE and phosphocellulose chromatography. The tropomyosin kinase requires Mg2+ for its activity, but Ca2+ and cyclic AMP are not needed. Increase in KC1 concentration decreased the tropomyosin kinase activity with over 90% inhibition at 0.2 M KC1. The alpha-tropomyosin subunit from rabbit and chicken skeletal muscle was phosphorylated about five times faster than the beta-tropomyosin subunit. Smooth muscle tropomyosin from chicken gizzard was not phosphorylated. The in vitro phosphorylation site in rabbit and chicken skeletal tropomyosins is a single serine residue close to the COOH terminus, a region intimately engaged in the head to tail polymerization of tropomyosin. Since the amino acid sequences of rabbit alpha- and beta-tropomyosin and chicken alpha-tropomyosin in this region are known, their phosphorylation sites can be unambiguously assigned as the penultimate residue, serine 283.

Computed tomographic, neurologic, and neuropsychological correlates of Huntington's disease

Twenty-six patients with Huntington's disease (HD) and three subjects at risk for HD were evaluated by computed tomographic, neurologic and neuropsychological examinations. These data were used to delineate the sequence of structural changes in early and intermediate HD, and the relationship of these changes to impairment of neurologic and cognitive function. CT scans documented an early neostriatal-frontal focus of atrophy in HD which spreads caudally over the cerebral cortex during the course of the disease. Chorea was positively correlated with caudate atrophy. Functional and cognitive (especially memory and visuospatial) impairments were strongly related to the degree of atrophy. Multiple regression analyses of CT and neuropsychological data further demonstrated that neostriatal changes make a significant contribution to the cognitive as well as to the motor impairments of HD patients.

Chromogenic cephalosporin spot test to detect beta-lactamase in clinically significant bacteria

lactamase production. Reacteroides melaniongenicus, 14

Comparison of the neuropsychological deficits associated with early and advanced Huntington's disease

Patients with "recently" diagnosed Huntington's Disease (RHD) were compared on a neuropsychological test battery to patients who have had the disease three to 15 years (AHD) and to intact controls. While the patients with HD showed general nonfocal deficits on the Wechsler Adult Intelligence Scale, the Wechsler Memory Scale, and tests of short-term memory and verbal fluency, the patients with RHD had focal deficits that stressed their memory deficits. The patients with RHD had IQs within the normal range, but their memory quotients, their performance on short-term memory tests, and their ability to search and retrieve from long-term memory were severely imparied. These results suggest that the cognitive deficits of patients with HD do not develop uniformally; memory disorders are early focal signs that precede the patients' more widespread intellectual deterioration.

Nature of Isoamylases Released, by Acidification, from Macroamylase Complexes

We describe observations of the isoamylase nature of the amylase released by acid from partially purified macroamylase complexes that are dissociable under acid conditions. The released isoamylases displayed the chromatographic characteristics previously found in the pancreatic type (P-type) and salivary type (S-type) of amylases in human serum and urine. The proportions of S- and P-types released from 30 macroamylase complexes varied over a much wider range than those proportions found in 27 normal sera. Of particular note was the relatively large number of cases in which there was a marked preponderance of S-type in the released amylase. These data testify further to the varied nature of cases of macroamylasemia, and contribute additionally to their systematic classification.

Simulation of macroamylasaemia by salivary-type ('S type') hyperamylasaemia

Hyperamylasaemia with low or normal urinary amylase excretion in the face of normal renal function has been noted to be indirect evidence for the existence of macroamylasaemia. A more refined indicator is a low ratio of renal amylase clearance to creatinine clearance. This report describes observations made in three patients, each of whom displayed the indirect features suggestive of macroamylasaemia. In none of these patients, however, could a serum macroamylase be demonstrated by chromatography. Ultracentrifugation was also done in one of the patients and likewise failed to disclose a macroamylase in the serum. When the isozyme nature of the serum amylase in each of these patients was examined, there was found to be a marked rise in activity of the salivary-type isoamylase (;S-type amylase'). The pancreatic-type isoamylase (;P-type amylase') was normal in one patient and perhaps slightly above normal in the other two. These data indicate that (1) S-type hyperamylasaemia may exhibit the indirect criteria taken to indicate macroamylasaemia and thereby simulate the latter disorder; and (2) unequivocal identification of macroamylasaemia requires the direct demonstration of the presence in the serum of a macromolecular amylase complex.