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The IncW plasmid R388 and the DNA region of Tn21 containing the Smr and the Sur genes are capable of RecA-independent recombination. This recombination occurs at a relatively high frequency (up to 10(-4) recombinants per recipient molecule) and results in integration of the two plasmids. No detectable repeats are formed in the process. The crossover points have been confined to a 0.4-kb homologous segment in both plasmids which contains a 59-bp DNA sequence presumably involved in the acquisition of new genes by Tn21 and its relatives (Cameron et al. 1986). It is likely that the recombination occurs precisely at this point. At least one trans-acting function (an integrase) is required for the site-specific recombination. It has been localized to a 1456-bp BstEII-BamHI fragment of Tn21 and can efficiently complement the integration of plasmids containing the integration site.
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The living organism is complex and depends on information transfer for its effective operation. One way to regard the organism is as a biological hierarchy in which each level not only serves a particular, circumscribed function but also contributes in an important way to the integrated performance of the organism as a whole. Two levels in the organization of biological functions are discussed to illustrate the principle of biological hierarchy: a subsidiary role, as exemplified by the role of the lungs in water and macromolecular exchange, and a primary function, as typified by the integrated performance of the cardiorespiratory apparatus in accord with the metabolic needs of the whole body. This hierarchical approach not only preserves the perspective for appreciating the coordinated behavior of the normal individual but also provides a vantage for assessing derangements produced by disease at any level in the biological hierarchy.
Robotic technology is going to have a profound impact on the clinical laboratory of the future. Faced with increased pressure to reduce health care spending yet increase services to patients, many laboratories are looking for alternatives to the inflexible or "fixed" automation found in many clinical analyzers. Robots are being examined by many clinical pathologists as an attractive technology which can adapt to the constant changes in laboratory testing. Already, laboratory designs are being altered to accommodate robotics and automated specimen processors. However, the use of robotics and computer intelligence in the clinical laboratory is still in its infancy. Successful examples of robotic automation exist in several laboratories. Investigators have used robots to automate endocrine testing, high performance liquid chromatography, and specimen transportation. Large commercial laboratories are investigating the use of specimen processors which combine the use of fixed automation and robotics. Robotics have also reduced the exposure of medical technologists to specimens infected with viral pathogens. The successful examples of clinical robotics applications were a result of the cooperation of clinical chemists, engineers, and medical technologists. At the University of Virginia we have designed and implemented a robotic critical care laboratory. Initial clinical experience suggests that robotic performance is reliable, however, staff acceptance and utilization requires continuing education. We are also developing a robotic cyclosporine which promises to greatly reduce the labor costs of this analysis. The future will bring lab wide automation that will fully integrate computer artificial intelligence and robotics. Specimens will be transported by mobile robots. Specimen processing, aliquotting, and scheduling will be automated.(ABSTRACT TRUNCATED AT 250 WORDS)
Establishing flow cytometric DNA analysis as a clinical routine procedure requires adequate and proven guidelines, by which the data can be obtained and interpreted to directly influence management of the individual patient with a specific neoplasm. The present paper is intended as a contribution to such guidelines, of which only fragments are available today. We have previously described a system of methods, designed for routine flow cytometric DNA analysis. In the present status report our experience, based on approximately 18,000 samples (clinical and experimental) is summarised. Sample acquisition with fine-needle aspiration, storage at -80 degrees C, internal standardization by chicken (CRBC) and trout red blood cells (TRBC), staining with propidium iodide (PI), and analysis in the flow cytometer is recapitulated, with emphasis on previously unpublished aspects. The method of statistical analysis which has an integrating role is described in some detail. A lack of linearity between channel number and DNA content was determined experimentally, and the coefficient of variation (CV) was found to decrease with increasing channel number. The corrections in the algorithm of deconvolution made necessary by these findings are fundamental for estimating the end results. The zero point adjustment and procedures for changing from one batch of standards to another are described. A systematic approach to interpretation of DNA histograms is attempted and illustrated by data from clinical specimens of malignant lymphoma, breast cancer, small cell lung cancer, cancer of the oral cavity, and bladder cancer. Some problems are still unsolved and visual inspection is required to determine if the quality of the individual histogram is satisfactory. Inspection of the fluorescence/light scatter dot-plot provides additional information for the recognition of artifacts. The results stress that good quality DNA histograms with as small CVs as possible are important for interpretation of the data. It is essential that statistical methods are employed to extract the key end-point results. These are the number of subpopulations and their relative representation, and for each subpopulation the DNA index (DI) and the fractions of cells in the cell cycle phases. For the DNA data to have any rationally based impact on clinical decision making, it must be demonstrated that they have an independent prognostic value. Strategies for final evaluation are discussed. Multicenter trials on fresh material, to accrue quickly the number of patients necessary for firm conclusions, are suggested.
Health care providers and insurers moving to form networks face a raft of state regulations on the purchase of equipment or the addition of new services, selective contracting, the hiring of physicians, referral practices and licensure. Two of these of regulations, the "any-willing-provider" laws and certificate-of-need laws, are making headlines in some states.
Physician group practices, like other providers, are experiencing the rapid transition to a new health care environment dominated by managed care penetration, at-risk capitation, and reform-related changes. Just how quickly things are changing is revealed by a new nationwide survey, which was conducted by Hospitals & Health Networks, the American Group Practice Association, Alexandria, VA, and Hamilton/KSA, Atlanta.
A mycobacteriophage D29 DNA fragment cloned in pRM64, a shuttle plasmid that transforms Mycobacterium smegmatis, was sequenced. The determined sequence was 2592 nucleotides long and had a mean G+C content of 63.7 mol%, similar to that of mycobacterial DNA. Four ORFs were identified: one with strong homology to dCMP deaminase genes; one homologous to mycobacteriophage L5 gene 36, whose function is unknown; one encoding a possible excisase; and one encoding an integrase. The intergenic region between the putative excisase gene and the integrase gene had a lower than average G+C content and showed the presence of the same attP core sequence as mycobacteriophage L5. Transformation experiments using subclones of pRM64 indicated that the integrase gene and all the intergenic region were essential for stable transformation. A subclone containing the integrase gene and the core attP sequence was able to transform but recombinants were highly unstable. Southern analysis of total DNA from cells transformed with pRM64 and its derivatives showed that all the plasmids were integrated at one specific site of the bacterial chromosome. A recombinant exhibiting a high level of resistance to the selective drug kanamycin had two plasmids integrated at different sites. These results demonstrated that the D29 sequences contained in pRM64 were integrative, indicating that the generally hold view of D29 as a virulent phage must be reviewed.
In many ways, acute hospital care and hospice care are two very different health care modalities based on two very different philosophies. Acute hospital care is primarily curative in nature, and of course, hospice is palliative care. This major philosophical difference renders understanding, appreciation, and relinquishing care to each other difficult, and at times impossible. Collaboration between the two is fraught with barriers and, therefore, requires facilitation. The initiation of this hospice nurse liaison program required vision and risk taking as well as understanding and appreciation of the contributions of both acute care and hospice care. The outcomes of patient and staff satisfaction, decreased length of stays, increased appropriate hospice referrals, decreased costs, and increased communication and collaboration between the hospital and hospices validate the worthiness of the program.
The care of pediatric cancer patients continues to grow in complexity. Paradoxically, treatment regimens grow more intensive, while regulatory pressures mandate more outpatient care. The challenge is to integrate services around episodes of illness and encounters over periods of 1-3 years. The approach of the author's clinic has been to create seamless relationships that place the patient at the center of care and address the major boundaries patients face. The inpatient-outpatient boundary has been effectively breached by an inpatient case manager and the simultaneous temporary rotation of an inpatient nurse to the outpatient area for specialty training. Discharge planning has been improved by sharing a nurse with the clinic's major home health care company, providing a direct clinic-home health liaison for patients. Ongoing formal evaluations have documented the effects of the institution of each part of the program. These surveys have indicated that inpatient staff participating in the outpatient rotation are more satisfied with the continuity of care and the availability of divisional resources. Patient satisfaction was extremely high and pediatric oncology discharge planning was rated significantly higher than other pediatric services. Despite rapid growth of the oncology service since 1985 and the personal intensity of care, length of stay has shortened and the number of staff has not required excessive increases to meet the needs of the new model.
We developed a prepacked mixing system for the preparation of bone cement. The system is based on mixing and collection of bone cement under a vacuum and serves as both the storage and mixing device for the cement components, thereby minimizing the exposure of the operating staff to the monomer and the risk for contamination of the cement during preparation. We evaluated the system using Palacos R and Simplex P. The cement produced was compared with cement obtained from a commercially available mixing system. Temperature evolution during curing, handling characteristics, density, and porosity of the cement obtained were analyzed. The results showed that the experimental system produces cement with physical properties (i.e., setting times and temperature, porosity, and density) equal to or better than those obtained with commercially available systems. Reducing the amount of monomer in the experimental system led to a reduction of the curing temperature without compromising the physical properties of the cements.
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