Biomedical subjects
Publications and source records attributed to C A Quinn.
Breast-imaging technology has improved in ways that allow one not only to detect breast cancer earlier, but also to distinguish benign from malignant lesions better. These capabilities are influencing the approach to breast cancer. We review current trends and issues for the non-radiologist.
A glucose-permeable hydrogel (97% water by mass) was formed by cross-linking an 8-armed, amine-terminated poly(ethylene glycol) (PEG) derivative with a di-succinimidyl ester of an alpha,omega-dipropionic acid derivative of PEG in aqueous solution at room temperature. The gel was evaluated as a biocompatible interface between an amperometric glucose electrode and the subcutaneous tissue of a rat. Over a glucose concentration range of 0-30 mM, the loss in sensitivity to glucose caused by the application of the hydrogel was 34% and the reduction in limiting current at high glucose concentration (30 mM) was 35% at 37 degrees C for films that were approximately 0.06 mm thick, an acceptable loss. Hydrogel and Pellethane samples were subcutaneously implanted in male Sprague-Dawley rats for 7 days. The explanted samples were thin-sectioned, stained and examined under a light microscope. While the Pellethane samples were encapsulated with tissue consisting of macrophages, neutrophils, foreign body giant cells, fibroblasts and collagen, the PEG samples had very few adherent cells. The results show this system to be a good candidate for providing biocompatible interfaces for sensors, especially oxidoreductase-based sensors.
Regulatory changes concerning the use of physical restraints in nursing homes have stimulated an examination of restraint use practices in other care settings. Caregivers are receiving mixed messages about appropriate restraint use in the hospital. Legal decisions are ambiguous in terms of the nurse's liability for restraint decisions, and the use of restraints may create a conflict between respecting patient autonomy and acting in the patient's best interest. Recent research does not support the belief that restraint use prevents patient injuries, but continues to document the untoward effects of restraints. Restraint reduction efforts have been successful in nursing homes, and many strategies can be adapted in acute care. As the movement to integrated systems of care places increased emphasis on continuity of services across settings and improved client outcomes, restraint practice is one area where interinstitutional collaboration and coordination must occur. The advanced practice nurse is in a key role to facilitate continuity of restraint reduction efforts.
An UV-sensitive class of photoreceptors exists in all regions of the retinas of mantis shrimps. UV photosensitivity apparently resides in rhabdomeres of the eighth retinular cell (R8) that lies atop each rhabdom; and in ommatidia where the R8 rhabdomere consists of microvilli parallel in a single direction, sensitivity is maximal when the e-vector of plane-polarized light is parallel to the microvilli. Spectral sensitivity of the UV photoreceptor peaks at 345 nm and is best explained by the presence of a photopigment with lambda max near 325 nm overlain by material that absorbs UV light at wavelengths below approximately 350 nm. Rhabdomeres of R8 cells in several different retinal regions of a variety of species examined contain a photopigment absorbing maximally below 340 nm. Under appropriate conditions, a metapigment with lambda max near 460 nm can be formed. UV vision may be useful for enhancing the visual contrast of midwater predators or prey.
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Cryptosporidium is a parasite of the human gastrointestinal tract that can cause life-threatening diarrhea in immunodeficient patients. Although more than 80 agents have been tried with occasional anecdotal success, treatment remains primarily limited to hydration. A 38-yr-old homosexual man with antibody to human immunodeficiency virus and Cryptosporidium-related diarrhea is described. The patient excreted 6-12 L of stool per day for at least 3 mo, 2 of them spent in the hospital. Trials with more than 6 antidiarrheal medications were ineffective. The patient received bovine colostrum hyperimmune to Cryptosporidium by direct duodenal infusion. During infusion, the patient's fecal output decreased to less than 2 L per day, and 48 h after treatment, stools were formed and oocysts to Cryptosporidium were absent. The patient remained asymptomatic for 3 mo. Hyperimmune bovine colostrum offers an exciting new therapy for cryptosporidiosis; controlled trials to establish efficacy should be undertaken and the active factor(s) characterized.
While the importance of ethics content in the nursing curriculum is recognized, few guidelines exist to aid faculty in decisions regarding 'essential' content. Comparison of documents from the Hastings Center Institute of Society, Ethics and the Life Sciences, and the American Association of Colleges of Nursing suggests that outcomes for the undergraduate nursing curriculum reflect the goals of both undergraduate and professional ethics education as identified by the Hastings Center study. Faculty are faced with the challenge of adequately addressing ethics in an already filled undergraduate curriculum. The conceptual integration of traditional clinical ethics with professional socialization and issues of professionalism provides a workable approach for identifying and integrating the necessary ethics content. Within this integrated approach the author identifies seven areas essential to the undergraduate curriculum: the moral ideals of the nursing profession, clarification of personal and professional values, moral issues/dilemmas common to nursing practice, recognizing ethical issues, basic ethical theory and principles, practice in analysis and debate, and the moral nature of a profession.
Cryptosporidium sp. causes fulminant diarrhea and chronic infection in immunocompromised, particularly human immunodeficiency virus-infected, persons. The lack of in vitro cultivation and a suitable animal model has limited development of effective treatment. We describe two new mouse models of chronic symptomatic cryptosporidiosis in adult athymic mice and in T-cell subset-depleted mice. A progressive infection, fatal within 4 months, occurred in most adult athymic mice; a few developed stable infections. Symptoms included dehydration, weight loss, intermittent diarrhea, and jaundice. Pathologic abnormalities and organisms localized in the intestine in stable infections but involved the hepatobiliary tree and pancreas in others. Lymphoid cells from histocompatible, Cryptosporidium sp.-immune mice cured infected nude mice. Identical infections occurred in neonatally infected BALB/c mice treated with anti-CD4 monoclonal antibodies alone or also with anti-CD8 monoclonal antibodies; the mice were cured when the monoclonal antibody treatments were stopped. These models will be useful in definition of the immune defects that permit chronic cryptosporidiosis to develop and in assessment of treatment modalities.
We have used mouse and human cDNA probes to map the chromosomal position of the N-CAM gene in the human genome. Southern analysis of DNA isolated from a panel of mouse-human somatic cell hybrids has assigned the N-CAM gene to chromosome 11. This assignment was found with both mouse and human N-CAM cDNAs.
Monoclonal antibody 30.2A8 was produced by a hybridoma made by fusing cells from rats that had been immunized with rat-human muscle cell hybrids. The 30.2A8 reacts with a differentiation antigen in human skeletal muscle that is synthesized by myoblasts but not myotubes. The gene controlling synthesis of the antigen recognized by 30.2A8 was found to be encoded by human chromosome 15.
A one-month crossover trial comparing Piloplex 3.4% b.i.d. with pilocarpine 2.0% q.i.d. was conducted to compare the effectiveness of the 2 drugs in reducing the intraocular pressure of ocular hypertensive and open-angle glaucoma in subjects previously controlled with pilocarpine 2.0%. For both groups the mean IOP increased slightly from baseline with pilocarpine and decreased significantly from baseline with Piloplex. The side effects of both treatments were minor. Piloplex and pilocarpine treatment were both associated with eye dryness; Piloplex was associated with lacrimation in 2 subjects. This controlled study showed that Piloplex 3.4% b.i.d. was more effective than pilocarpine 2% q.i.d. in lowering intraocular pressure.
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Somatic cell hybrids have been prepared at high frequency between the rat muscle cell line L6 and human fetal muscle cells. The hybrid cells express several human gene products including an antigen, 12E7, controlled by the human X chromosome, Thy-1, and several human isoenzymes. In addition, one clone (37-11) expresses a human muscle-specific surface antigen (5.1 H11) and, under appropriate conditions, can be induced to form myotubes. Upon myotube formation, this clone switches on the production of the human muscle-specific creatine kinase (ATP:creatine N-phosphotransferase, EC 2.7.3.2) M subunit. This is an example of developmental regulation of human muscle-specific genes in somatic cell hybrids.
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Procedures for the diagnosis of Br. ovis infection in rams were evaluated by examining 10 rams artificially infected by preputial inoculation. Observations were undertaken at weekly intervals for 1 year to follow changes in clinical, bacteriological and serological findings. Clinical lesions were detected in 1 ram 3 weeks after inoculation and in all rams by 8 weeks; lesions were undetectable in 3 rams at the completion of the trial. The presence of inflammatory cells in semen samples was the earliest indication of infection being demonstrated in 2 rams at 2 weeks and in all rams by 8 weeks; subsequently 86% of samples were positive. Br. ovis was detected in semen smears from 3 rams at 4 weeks but only one in all rams (at 27 weeks); overall 52% of semen smears were positive from 4 weeks onwards. Br. ovis was cultured from semen of 5 rams after 4 weeks and from all rams at 5 weeks; therafter 97% of samples were positive. All rams developed significant titres to the CFT between 2 and 9 weeks; therafter the CFT was a reliable indication of infection in 6 rams, highly suggestive in 3 and unreliable in one. By 8-10 weeks all rams developed significant titres to the IHA which were then maintained in all rams for the remainder of the trial.
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Results of the initial clinical evaluation in 20 human subjects of a subcutaneously implanted microsensor-based amperometrically glycemia-monitoring system, carried out between April 1994 and June 1995, are reported. The system was based on the electrical connection ("wiring") of the reaction centers of glucose oxidase to a gold electrode and on elimination of the chemicals that interfere with glucose monitoring through their horseradish peroxidase-catalyzed oxidation by internally generated hydrogen peroxide. The sensor was finer than a 29-gauge needle and had no leachable components. Because of its high selectivity for glucose, the sensor output was virtually nil at zero glucose level. This enables prompt "one-point" in vivo calibration of the sensor with a single blood glucose sample. Microsensors were subcutaneously implanted in ten nondiabetic and ten insulin-dependent diabetes mellitus (IDDM) volunteers. All subjects underwent standard meal tests and intravenous glucose-tolerance tests (IVGTT) in addition to hourly plasma glucose measurements. The sensor signals were continuously recorded, and the glucose concentration estimates were derived by calibrating the sensor using a single blood sample (one-point calibration). Regression analysis revealed that the sensor-estimated glucose concentrations were linearly related to the plasma glucose concentrations (r2 = 0.75) over a wide glucose concentration range (2-28 mmol/L) (sensor estimate = plasma 0.96 + 0.26 mmol/L). The difference between the estimated and actual glucose concentration was -0.13+/-0.23 mmol/L [mean +/-95% confidence interval (CI), n = 546], and 95% of the estimates fell in clinically acceptable zones of the Clarke error grid. The sensing delay time was 10.4+/-2.3 min as measured by the IVGTT. The subjects reported no discomfort associated with wearing the sensors.