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Biomedical subjects

L Smith

Publications and source records attributed to L Smith.

At least 739 records · Page 41Linked to original sources

Malignant melanoma of the skin of the nose.

Seventeen patients with cutaneous melanomas of the nose were treated at the M. D. Anderson Hospital during the years 1944-1978. The local recurrence rate was 6 per cent. The two-year survival rate was 82 per cent; the five-year survival rate, 29 per cent; the ten-year survival rate, 12 per cent. Only 20 per cent of the patients developed histologically positive lymph nodes, and all died of the disease. Wide local excision with skin grafting is the treatment of choice, with a modified neck dissection and/or superficial parotidectomy reserved for subsequent nodal metastasis.

Adult↗

Suicidality in panic disorder: a comparison with schizophrenic, depressed, and other anxiety disorder outpatients.

Recent findings by Weissman, Klerman, Markowitz, and Ouellette (1989) that subjects with panic disorder, with and without comorbid conditions, may be at increased risk for suicide attempts have been controversial. In an attempt to further investigate this finding, we utilized the original National Institute of Mental Health Epidemiological Catchment Area (ECA) suicide questions in an outpatient psychiatric clinic. We examined patients with panic disorder (n = 101). other anxiety disorders (n = 47), schizophrenia (n = 22). and major depression (n = 19). No significant differences were found among all four groups on any of the ECA suicide ideation questions. Only two (2%) of the panic disorder patients and none of the other groups made a suicide attempt in the past year. While 17% of patients with panic disorder and 9% of patients with other anxiety disorders reported having made a suicide attempt at some other time in their life, the schizophrenic (33%) and depressed groups (40%) reported significantly greater histories of suicide attempts. In a forward stepwise regression analysis for panic disorder patients, a history of substance abuse and comorbid depression predicted suicidality. The actual clinical risk for suicide attempts in panic disorder patients appears to occur when they suffer with comorbid diagnoses. These results highlight the need to aggressively treat panic disorder patients so they do not suffer the all-too-common sequelae of depression and substance abuse.

Adult↗

Bacteriologic studies on electronic hospital thermometers.

Electronic thermometers used in many hospitals require insertion into the mouth of a temperature-sensing probe covered by a pre-packaged probe cover. Handling procedures used by hospital personnel can lead to inadvertent manual contact with the probe cover. We attempted to determine the rate of non-sterility of these probe covers under normal hospital conditions and the extent to which pathogens could be detected on these and other components of the thermometer. Probe covers were removed before entry into the patient's mouth and aseptically inoculated into fluid thioglycollate medium. Subcultures were made to appropriate differential media. Over a 13-week period, 180 covers were cultured on two private hospital services. Forty-three percent were found to be non-sterile; control covers from central supply were only 6% non-sterile. Four percent of the probe covers harbored potential pathogens: coagulase positive Staphylococcus aureus, Streptococcus pyogenes, Enterobacter, and Bacteroides. No attempt was made to correlate these findings with infection. These results indicated a potential infection hazard for high-risk patient groups and a need by hospital personnel to consider this as a possible source of contamination.

Bacteria↗

CD4+ murine T cells develop from CD8+ precursors in vivo.

The adult murine thymus contains four subpopulations of thymocytes defined by the T-cell surface antigens CD4 (L3T4) (a marker of helper T cells) and CD8 (Lyt2) (a marker of cytotoxic/suppressor T cells): CD4+8- and CD4-8+ (single positives), CD4+8+ (double positives) and CD4-8- (double negatives). To understand how T cells develop in the thymus, it is important to determine the lineage relationships among these subpopulations. In particular, the status of double positives, which make up approximately 80% of the total thymocyte population, has long been controversial. Some purpose that double positives are 'dead-end cells' that all die in the thymus, perhaps because they have been rejected by some selection process. Others suggest that, although most double positives die in the thymus, some develop into the more mature single positives that leave the thymus. The experiments presented here show that repeated injections of anti-CD8 monoclonal antibodies block the development of CD4+ cells, demonstrating that these cells develop from CD8+ precursors, probably double positive thymocytes, in vivo.

Animals↗

Differentiation potential of subsets of CD4-8- thymocytes.

Precursor T cells in the thymus are contained within a subpopulation of thymocytes that lack the markers CD4 and CD8. We have examined the heterogeneity of these cells by flow cytometric analysis, and defined four subpopulations using the cell surface markers Thy-1, J11d and the IL-2 receptor (IL-2R). The J11d+ subset of CD4-8- cells all bear the antigen Thy-1, and some express the IL-2R. Staining and RNA analysis of J11d+ cells suggest that some express receptors of the CD3 gamma delta type, but none express CD3 alpha beta receptors. In fetal thymus organ culture, the J11d+ cells diversify to form 'cortical type' CD4+8+ cells and 'medullary type' cells expressing either CD4 or CD8; in vivo they repopulate the thymus of an irradiated host and seed the periphery with T cells. In contrast, the J11d- subset of CD4-8- thymocytes do not all bear Thy-1 and none express the IL-2R, but some express antigen receptors of the CD3 alpha beta type. They have more limited diversification potential in organ culture, and in vivo fail to recolonize the irradiated host in a homing-independent assay. We conclude that they are not precursor T cells, but rather a side-branch from the main line of T cell differentiation.

Aging↗

The national exposure research laboratory's consolidated human activity database.

EPA's National Exposure Research Laboratory (NERL) has combined data from 12 U.S. studies related to human activities into one comprehensive data system that can be accessed via the Internet. The data system is called the Consolidated Human Activity Database (CHAD) and is available at http:// www.epa.gov/nerl/. CHAD contains 22,968 person days of activity and is designed to assist exposure assessors and modelers in constructing population "cohorts" of people with specified characteristics that are suitable for subsequent analysis or modeling. This paper describes the studies comprising CHAD and the various intellectual foundations that underlay the gathering of human activity pattern data. Next, it provides a brief overview of the Internet version of CHAD, and discusses how the program was formulated. Emphasis is placed on how activity-specific energy expenditure estimates were developed. Finally, the paper recommends steps that should be taken to improve the collection of activity data that would improve energy expenditure estimates and related information needed for physiologically based exposure dose modeling efforts.

Activities of Daily Living↗

Cisplatin-induced nonimmunologic adsorption of immunoglobulin by red cells.

Antibodies to cisplatin, an extensively used anticancer chemotherapeutic agent, have been implicated previously as a cause of immune hemolytic anemia. Investigation of a suspected case of cisplatin-induced hemolytic anemia in a 40-year-old man demonstrated that IgG could be adsorbed nonimmunologically by reagent red cells in vitro. This phenomenon was found to be a source of possible error in the interpretation of studies identifying specific cisplatin antibodies. Furthermore, cisplatin was found to be capable of producing a positive direct antiglobulin test (DAT), owing to the nonspecific adsorption of immunoglobulin and complement in vivo. Although this finding did not result in acute hemolysis, it may cause confusion in the investigation of DAT-positive hemolytic anemias. We question whether previous reports of cisplatin-induced hemolytic anemia are accurate in their assessment that such hemolysis was mediated immunologically. Future studies of suspected cases of hemolysis induced by this drug should include serologic investigation adequate to demonstrate the presence of specific cisplatin antibodies. A positive DAT in such patients should not be considered proof of drug-induced immune hemolytic anemia.

Absorption↗

[Hypermethylation as a potential prognostic factor and a clue to a better understanding of the molecular pathogenesis of medulloblastoma--results of a genomewide methylation scan].

BACKGROUND: The molecular mechanisms controlling initiation and progression of medulloblastomas are largely unclear. Changes in DNA methylation of promoter regions have been shown to disturb the expression of growth regulatory genes. PATIENTS AND METHODS: We evaluated DNA methylation patterns in 17 medulloblastomas, 5 stPNETs and 5 medulloblastoma cell lines using Restriction Landmark Genomic Scanning (RLGS), a method displaying up to 2.000 potential gene loci in a single gene. To test whether previously characterized tumor suppressor genes are affected by hypermethylation we performed MS-PCR for p15INK4B, p16INK4A, VHL, TP53 and E-cadherin. RESULTS: The analysis of RLGS profiles from tumors revealed an abundance of hypermethylation in primary tumors and cell lines. Extrapolated to the human genome with its approximately 36,000 genes a total of 420 loci become hypermethylated in the tumor genomes. The previously characterized medulloblastoma breakpoint cluster in 17p11.2 appears to be a hotspot for aberrant methylation. Cox regression analysis of survival data identified seven CpG islands for which hypermethylation is suggestive of a poor prognosis. MS-PCR analysis of known genes demonstrated hypermethylation of p16INK4A in a limited number of tumors. The pattern of DNA hypermethylation was similar in medulloblastomas and stPNETs. However, some CpG islands were shown to be specific for a tumor type, while others were shared targets. CONCLUSIONS: Hypermethylation is a common abnormality in primary medulloblastomas and supratentorial PNETs. Several hundreds of CpG islands are potential targets for methylation in medulloblastomas including the breakpoint cluster in 17p11.2. The methylation status of certain gene sequences appears to be associated with the clinical outcome. Promoter hypermethylation has an outstanding potential as a marker for the identification of novel tumor suppressors as well as diagnostic and therapeutic targets in medulloblastomas.

Adolescent↗

Blood lead levels in Toronto children and abatement of lead-contaminated soil and house dust.

South Riverdale in Toronto, Canada, underwent a lead-abatement program. In 1988, lead-contaminated soil was replaced at 970 properties, and in 1989, professional housecleaning for lead removal was conducted in 717 households. The effect of "abatement" on blood lead levels in young children was investigated. Data were analyzed from 12 cross-sectional blood-screening surveys that were conducted during an 8-y period in South Riverdale and in two comparison areas. Responses regarding behavioral, household, lifestyle, neighborhood, and environmental factors, all of which were gleaned from associated questionnaires, were also analyzed. Response rates varied between 32% and 75%. During the years between 1984 and 1992, blood lead decreased in all study areas. There appeared to be a minimal blood lead level of 2-3 micrograms/dl for urban Ontario children who were less than 6 y of age. The significant difference between South Riverdale and the control areas disappeared by 1992. Although abatement activity in South Riverdale was associated with an accelerated decline in blood lead levels, it was difficult to distinguish this from effects of decreased Toronto air lead levels or decreased smelter emissions. Within South Riverdale, abatement appeared to be associated with a slower decline in blood lead levels over time, likely the result of selection bias, soil mixing, or recontamination from the smelter. No difference was observed between the separate effects of housecleaning or soil replacement. The findings could neither strongly support nor refute beneficial effects of abatement.

Analysis of Variance↗

The relationship between coping strategies and GHQ-scores in nurses.

This paper discusses the development of a situation specific questionnaire for measuring coping with shiftwork. Previously, no standardized measure appears to have been developed, even though coping behaviour is considered to be an important factor in determining tolerance to shiftwork. The results from this study indicated that the present questionnaire may have some potential. Its psychometric qualities were relatively good. Coping scores were related to psychological health, measured by GHQ-12. Analysis of variance showed a main effect of only one of the subscales (disengagement strategies) on GHQ and also a reliable interaction between disengagement and engagement on GHQ-scores. Further research into the effect of coping strategies on shiftwork tolerance is suggested.

Adaptation, Psychological↗

The perceptions and feelings of shiftworkers' partners.

The views and feelings of shiftworkers' partners are rarely sought in shiftwork research. For this study, the partners of UK nuclear power shiftworkers were surveyed in relation to how their spouse's shiftwork affected them personally. A sizeable proportion of partners reported being unhappy with their spouse's shiftwork and that their lives were disrupted quite substantially by it. Partners were also asked for their perceptions of the shiftworkers' shift-related problems. Importantly, it would appear that shiftwork had a significant negative impact upon the lives of the partners. In view of these results and the relative paucity of research in this area, future investigation of the effects of unusual work hours upon shiftworkers' partners and families is warranted.

Adult↗

Is there an optimum number of night shifts? Relationship between sleep, health and well-being.

By concentrating on the impact of a specific shift-system feature on the well-being of those concerned, rather than on the impact of the shift system as a whole, one might be able to offer more meaningful suggestions as to what constitutes a better form of shift system. The present study focused on the impact of the number of consecutive night shifts worked on the health and well-being of two groups of nurses (permanent night and rotating shift). All nurses completed a copy of the Standard Shiftwork Index, which is a set of questionnaires designed for comparing the effects of different types of shift system on large groups of workers. It includes measurements of psychological ill-health, physical ill-health, chronic fatigue, social and domestic disruption, attitudes towards shiftwork, sleep quality and sleep habits. Results showed clearly the impact of the number of consecutive nights worked on health and well-being, not directly, but indirectly through the impact on sleep duration and sleep quality. Sleep duration was shown to increase with more consecutive nights worked. This in turn was found to predict sleep quality, which in turn was found to be the stronger direct predictor of psychological and physical ill-health i.e. better health was associated with longer and better quality sleeps. Explanations in terms of circadian adaptation are discussed.

Adaptation, Physiological↗

Predicting communicative competence at 2 and 3 years from pragmatic skills at 10 months.

It is proposed that children play an important part in determining the kinds of linguistic experience they receive, influencing their language environment by means of early pragmatic communication. These early behaviours may also be predictive of later communicative competence. As a preliminary investigation into the wider implications of children's potential influence over their linguistic environment, a study was undertaken which looked at infant pragmatic signalling systems and joint engagement skills, to establish whether these early interactive behaviours might be related to children's subsequent communicative development. During the course of the study, the frequency and distribution of early pragmatic behaviours in a random sample of 145 10-month-old infants were investigated, and their subsequent language development followed up at ages 24 and 36 months. The study examined (a) the predictive validity of specific pragmatic behaviours at age 10 months for language development at age 24 months and (b) the specificity and stability of profiles of communicative disability at 2 and 3 years. A subset of behaviours was identified which would have correctly predicted 82.4% of children found to have communicative difficulties at 24 months and 85.4% of those who did not. Predictive language profiles drawn up at age 24 months were substantially confirmed when the children were reassessed at age 36 months. It is proposed that specific early communicative behaviours may be predictive of a child's subsequent linguistic development. Additionally, 2-year-old children will be exhibiting certain patterns of language acquisition which may be significant for subsequent linguistic development. Implications for intervention are discussed.

Child Behavior↗