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Biomedical subjects

C Allen

Publications and source records attributed to C Allen.

At least 145 records · Page 8Linked to original sources
PubMed1990

Self-generated mnemonics for enhancing free recall performance in older learners.

The effectiveness of self-generated mnemonic strategies for free-recall list learning was examined in 94 older community-dwelling adults. Participants were presented with a list of 19 nouns and were given seven minutes to commit the list to memory with three minutes for recall. Performance was measured immediately following recall and after a 2-day delay. Forty-five percent of the participants reported using a specific organizational mnemonic encoding strategy to facilitate recall. At both immediate and delayed recall, those individuals who reported using a well-articulated mnemonic outperformed those reporting the use of repetition or making simple associations. The results suggest that many older adults can spontaneously generate specific elaborative encoding strategies and that pre-existing encoding skills should be assessed prior to remedial memory training for older adults.

Aged↗
PubMed1990

Detached ciliary tufts. Comparison with intestinal protozoa and a review of the literature.

Detached ciliary tufts are structures of doubtful pathologic significance that are normally present in many body fluids. However, their existence is not widely appreciated by pathologists practicing routine laboratory medicine. If they are observed, their practical clinicopathologic importance is that, because of their vigorous ciliary motion in wet mounts, they can imitate ciliated protozoa and pose a diagnostic dilemma. The authors present a brief review of the literature on detached ciliary tufts and a morphologic comparison with the more commonly encountered intestinal protozoa.

Adolescent↗
PubMed1989

Nucleotide sequence of the Erwinia chrysanthemi gene encoding 2-keto-3-deoxygluconate permease.

The phytopathogenic bacterium Erwinia chrysanthemi produces a group of pectolytic enzymes able to depolymerise the pectic compounds in plant cell walls. The resulting tissue maceration is known as soft rot disease. The degraded pectin products are transported by 2-keto-3-deoxygluconate permease into the bacterial cell, where they serve as carbon and energy sources. This H+ coupled transport system is encoded by the kdgT gene; we report the nucleotide sequence of kdgT. It is encoded by an open reading frame (ORF) of 1194 bp, which is preceded by an Escherichia coli-type promoter region. The ORF encodes a protein with 398 amino acid (aa) residues and a predicted Mr of 48,550. As would be expected for a membrane protein, it is very hydrophobic, containing 63% nonpolar aa. However, the kdgT gene has no apparent evolutionary relationship to other genes encoding sugar transport proteins, such as lacY, melB or the E. coli citrate transport gene. Southern hybridization experiments indicate a strong homology between the Er. chrysanthemi and E. coli kdgT genes; there is also a second region on the E. coli chromosome with homology to kdgT. The kdgT gene is located near the ade-377 marker on the Er. chrysanthemi chromosome (equivalent to the region between 20 and 30 min in E. coli), whereas the E. coli kdgT gene is located at 88 min. Thus, these two enterobacteria show some significant differences in their genomic organization.

Amino Acid Sequence↗
PubMed1989

Relation of tumor size, lymph node status, and survival in 24,740 breast cancer cases.

Two of the most important prognostic indicators for breast cancer are tumor size and extent of axillary lymph node involvement. Data on 24,740 cases recorded in the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute were used to evaluate the breast cancer survival experience in a representative sample of women from the United States. Actuarial (life table) methods were used to investigate the 5-year relative survival rates in cases with known operative/pathologic axillary lymph node status and primary tumor diameter. Survival rates varied from 45.5% for tumor diameters equal to or greater than 5 cm with positive axillary nodes to 96.3% for tumors less than 2 cm and with no involved nodes. The relation between tumor size and lymph node status was investigated in detail. Tumor diameter and lymph node status were found to act as independent but additive prognostic indicators. As tumor size increased, survival decreased regardless of lymph node status; and as lymph node involvement increased, survival status also decreased regardless of tumor size. A linear relation was found between tumor diameter and the percent of cases with positive lymph node involvement. The results of our analyses suggest that disease progression to distant sites does not occur exclusively via the axillary lymph nodes, but rather that lymph node status serves as an indicator of the tumor's ability to spread.

Breast Neoplasms↗
PubMed1989

Monoclonal antibody 5.5 reacts with p8,14, a myeloid molecule associated with some vascular endothelium.

The movement of mononuclear phagocytes and neutrophils from the circulation into tissues is a process which is not completely understood. Monoclonal antibody 5.5 is specific for an 8/14-kDa molecule known variously as the CF antigen, L1 molecule or MRP8 and 14. We show that this molecule, which will be named p8,14 in this study, is expressed in all circulating monocytes and neutrophils as an intracellular product (as well as some types of epithelium). Tissue staining patterns suggest that when monocytes and neutrophils adhere to vascular endothelium, they release this molecule onto the associated endothelium. This process occurs with single monocytes and when monocytes form part of an inflammatory infiltrate. Monoclonal antibody 5.5 does not react with cultured endothelial cells even when stimulated with phorbol ester, tumor necrosis factor, interferon-gamma or interleukin 1 alpha providing further evidence that myeloid cells are the source of the p8,14 in this interactive process. Monocytes which have moved further into such tissues and tissue macrophages in general are monoclonal antibody 5.5 negative, suggesting that the ability to synthesize this molecule may be lost when monocytes leave the circulation and enter tissues. These results indicate that p8,14 plays a role in the interaction between myeloid cells and the vascular endothelium to which they adhere prior to leaving the circulation.

Antibodies, Monoclonal↗
PubMed1989

A medical review approach to Medicare outpatient documentation.

Blue Cross of California has recognized the problem of reimbursement delays due to Medicare claims that have been returned or denied. The information in this article applies to the medical review process and suggests an interpretation of the new Medicare outpatient guidelines used by the Blue Cross of California Medicare reviewers. As a solution to the problem of delayed reimbursement, medical reviewers--who are also practicing occupational therapists--offer an explanation of the Medicare review process and suggestions for correcting technical billing errors. Methods for keeping complete and timely medical records are discussed, with the suggestion that clinicians follow these methods from the start of care. A process for documentation is presented that will clearly prove to the medical reviewer the need for the special skills of an occupational therapist. This article also proposes reasons for noncoverage because of insufficient medical necessity. It is important to note, however, that variance between fiscal intermediaries' interpretations and requirements exists nationwide. This article, therefore, represents only one fiscal intermediary's approach to reviewing claims and medical records.

Ambulatory Care↗
PubMed1989

The policy forum. A panel of experts may provide the best guidelines for complex ethical decisions.

Policies on complex issues such as the termination of life-sustaining treatment can be developed and implemented through a variety of methods, but a facility's ethics committee may be the most appropriate forum. Since committee members' interests are often too diverse to deal with specifics that are organizationally useful, the facility should establish a subcommittee of experts. This committee should include physicians; nurses; one or more hospital administrators; a trustee; representatives from social services, respiratory therapy, and pastoral care; a social gerontologist; and an ethicist. The members should keep open the doors of communication to their peers to address their concerns, incorporate their input, and expand the educational process. This will alleviate the frustration sometimes encountered in policy implementation, where those who must carry it out have had no part in its formulation. Once the subcommittee has drafted a policy, the full ethics committee should discuss and refine it before forwarding it to the administration. After the administration has accepted it, the medical staff, employees, patients, and families need to be informed.

Ethics↗
PubMed1989

A blueprint for better service.

The authors review the thoughtful process that led an independent laboratory in Seattle from a mostly manual ordering/reporting system to a computer-based operation that has exceeded expectations for improved service to all of their laboratory customers.

Autoanalysis↗
PubMed1989

Behavior of human RPE cultured on Bruch's membrane and on necrotic debris.

Degeneration and necrosis of the retinal pigment epithelium (RPE) is found in several conditions associated with reactive alteration of the cell layer, and is probably involved in the formation of drusen and age-related macular degeneration. In the current study we describe a novel system for culturing human RPE. This system permits evaluation of the effect of necrotic material between the epithelium and Bruch's membrane, of drusen, and of other alterations in Bruch's membrane on the behavior of the RPE. In this system, dissociated RPE cells were seeded onto isolated Bruch's membrane. Cell behavior was assessed in areas with and without drusen, and also in areas covered with necrotic cells and fragmented debris. On both exposed Bruch's membrane and on the membrane covered with debris, the cells developed a polygonal shape, with a varying density of apical microvilli. The cultures were monolayered with some overlapping. In areas containing fragmented debris and dead cells, seeded RPE cells were found to adhere to the apical surface of necrotic cells, but were also seen to intrude between the necrotic debris and underlying Bruch's membrane, appearing to clear the membrane of such debris. Our study demonstrates the stability of epithelial histology of human RPE under not previously tested conditions. Further, it shows that the present system permits exposure of these cells to several in vivo physiological and pathological changes in a controlled in vitro environment.

Cells, Cultured↗
PubMed1988

Kikuchi's disease--apparent malignancy of a neck mass.

We report a case of Kikuchi's disease presenting as cervical lymphadenopathy in an adolescent. The original histological diagnosis in this case was a metastatic neoplasm. We wish to highlight the importance of this rare condition because of its potential for mimicking malignancy.

Adolescent↗
PubMed1988

The morphology of human cells from the choroid and retinal pigment epithelium grown in vitro on isolated Bruch's membrane.

Cells from samples of human choroidal tissue were collected and seeded onto isolated Bruch's membrane in vitro, and the morphology of the developing cultures was examined by light-, scanning electron- and transmission electron-microscopy. In early cultures, the cells showed a flattened, spread out appearance with short surface villi and a low degree of cellular overlapping. After 48 h, a shift towards a more elongated cell form was observed, and one week old cultures were composed of predominantly elongated cells with a pronounced degree of overlapping. In contrast, human retinal pigment epithelial cells seeded onto sheets of Bruch's membrane maintained a spread out epithelial morphology with a varying degree of overlapping throughout the culture period. The present system permits comparative studies on the behavior of choroidal and pigment epithelial cells under controlled conditions. It may serve as an in vitro model for disorders characterized by growth of these cells on Bruch's membrane in vivo.

Cell Membrane↗
PubMed1988

The effect of a pulsed neodymium-YAG laser on chorioretinal monolayered cell cultures.

The effect of a pulsed YAG laser on monolayers of chorioretinal cells maintained in vitro on plastic surface was examined. At the energy levels used, phase contrast microscopic visible lesions were observed at all focus distances up to 2 mm. Scanning electron microscopy demonstrated curling of detached sheets of cells, displacement of single cells, clustering of cells, and severe cell membrane damage at the edge of the lesions. The present system permits evaluation of the effect of different laser characteristics and application modes on the extent and morphology of damage in monolayers of human cells under easily controlled conditions.

Cells, Cultured↗
PubMed1988

Gonadotropin-producing pituitary adenoma in a man with long-standing primary hypogonadism.

Pituitary adenomas that secrete gonadotropins are generally believed to arise spontaneously rather than as a response to chronic primary gonadal failure. However, two women who were found to have gonadotroph adenomas several years after ovarian ablation have been reported. We describe a middle-aged man who developed bitemporal hemianopia and was found to have a large pituitary tumor 35 yr after castration. He had never received any replacement therapy. The tumor was considered to be a primary gonadotroph adenoma, rather than secondary gonadotroph hyperplasia, on the basis of its secretory capabilities, its reticulin patterns, and its specific immunostaining for human FSH beta, human LH beta, and alpha-subunit. Furthermore, the tumor did not decrease appreciably in size after 12 months of testosterone treatment, although plasma gonadotropin levels decreased. Unless the association of primary gonadal failure with a gonadotroph adenoma was coincidental, it suggests that some human gonadotroph adenomas may be secondary to failure of the gonads.

Adenoma↗