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Biomedical subjects

L Green

Publications and source records attributed to L Green.

At least 127 records · Page 7Linked to original sources
PubMed1995

Pseudotumor cerebri in systemic lupus erythematosus.

OBJECTIVE: To assess the association between pseudotumor cerebri (PC) and systemic lupus erythematosus (SLE), and to seek a pathogenic mechanism that may elucidate the appearance of PC in patients with SLE. DATA SOURCE: Original English articles having the terms SLE, PC, or benign intracranial hypertension in their titles were identified by Medline search. In addition we report three new patients with this association. STUDY SYNTHESIS: Thirteen articles were found and 21 patients were analyzed. DATA EXTRACTION: Of the reported 21 patients, 18 were previously reported and 3 new patients with coexisting PC and SLE are described. The clinical characteristics of the patients is presented. Patients with PC and SLE generally had a more severe course of SLE; renal involvement occurred in 79%, massive proteinuria in 47%, and hematologic abnormalities were detected in a third. A hypercoagulable state manifest by either recurrent thromboembolic events or a high anti-cardiolipin antibody titer was detected in 58% of the patients described. CONCLUSIONS: The association of PC and SLE is probably not coincidental. The high prevalence of serologic or clinical evidence of a hypercoagulable state suggests that microscopical thromboembolic events play a role in the genesis of PC.

Adolescent↗
PubMed1995

The incidence of melanocytic naevi in adolescent children in Queensland, Australia.

The aim of this study was to assess longitudinally the development of melanocytic naevi in children around the time of their puberty. In Queensland, Australia, 102 schoolchildren born mostly in 1977 or 1978, were examined annually on four occasions from 1990. All naevi on the body except for the scalp and parts covered by a bathing suit were counted by an experienced research nurse or trained assistant according to a set protocol. In addition, each subject's pigmentary characteristics were recorded and height, weight and pubertal status were assessed annually. The findings confirmed that the average number of naevi and average density of naevi (count per m2) on the whole body in boys and girls increase significantly with increasing age and increases were also seen on each of the following anatomic sites: face and neck, back and shoulders, and upper and lower limbs. Children who had a high baseline naevus count, or a large increase in skin surface area during the 3-year follow-up period had the highest absolute increases in naevus count but the smallest proportionate increases. Associations between baseline naevus counts and male sex, light brown or blonde hair, blue or hazel eyes, facial freckling and a tendency to sunburn, which have been previously reported, were also found. However, the independent relations of each of these factors to the increase in new naevi were more complex, once the effects of high naevus counts at baseline and increases in skin surface area were taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Detection of human growth hormone receptors on IM-9 cells and peripheral blood mononuclear cell subsets by flow cytometry: correlation with growth hormone-binding protein levels.

We have developed a method using flow cytometry to identify fluorescein-conjugated GH receptors (GHR) on IM-9 lymphocytes and circulating peripheral blood mononuclear cell subsets. Binding to IM-9 cells and peripheral blood mononuclear cells was concentration dependent and could be competitively blocked by the addition of unlabeled human GH, but not by the addition of rat or bovine GH or human insulin or PRL. Using two-color flow cytometric analysis, fluorescein-conjugated human GHR were readily detected on more than 90% of B lymphocytes and monocytes, but only variably on T lymphocytes. B Lymphocytes and monocytes had approximately 6000 GHR/cell. Using two-color flow cytometry, we identified GHR on circulating B lymphocytes in subjects with GH deficiency (n = 9), precocious puberty (n = 6), and Turner syndrome (n = 5) and in seven subjects with miscellaneous disorders, including familial short stature, bone dysplasia, Crohn disease, congenital adrenal hyperplasia, and acromegaly. The percentage of B lymphocytes expressing GHR in subjects with GH deficiency (mean +/- SD, 95 +/- 9%), precocious puberty (91 +/- 15%), and Turner syndrome (84 +/- 15%) was not different from that in normal volunteers (90 +/- 12%; n = 14). In 10 subjects, serum GH-binding protein levels were assayed simultaneously with B lymphocyte GHR. GH-binding protein was normal in all (mean, 1255 pmol/L; range, 773-1809). There was a good correlation between GHR expression on B lymphocytes and GH-binding protein levels (r = 0.75; P = 0.01). We postulate that GHR found on circulating B lymphocytes may contribute to the pool of receptors identified in serum as GH-binding proteins. Two-color flow cytometry appears to be an effective method for the detection of GHR on circulating peripheral blood mononuclear cell subsets. The evaluation of GHR on circulating B lymphocytes may prove to be a useful means of evaluating GH-GHR interactions in subjects with growth disorders.

Adult↗
PubMed1995

Prisoner's dilemma and the pigeon: Control by immediate consequences.

In three experiments pigeons played (i.e., chose between two colored keys) iterated prisoner's dilemma and other 2 x 2 games (2 participants and 2 options) against response strategies programmed on a computer. Under the prisoner's dilemma pay-off matrix, the birds generally defected (i.e., pecked the color associated with not cooperating) against both a random response (.5 probability of either alternative) and a tit-for-tat strategy (on trial n the computer "chooses" the alternative that is the same as the one chosen by the subject on trial n - 1) played by the computer. They consistently defected in the tit-for-tat condition despite the fact that as a consequence they earned about one third of the food that they could have if they had cooperated (i.e., pecked the "cooperate" color) on all the trials. Manipulation of the values of the food pay-offs demonstrated that the defection and consequent loss of food under the tit-for-tat condition were not due to a lack of sensitivity to differences in pay-off values, nor to strict avoidance of a null pay-off (no food on a trial), nor to insensitivity to the local (current trial) reward contingencies. Rather, the birds markedly discounted future outcomes and thus made their response choices based on immediate outcomes available on the present trial rather than on long-term delayed outcomes over many trials. That is, the birds were impulsive, choosing smaller but more immediate rewards, and did not demonstrate self-control. Implications for the study of cooperation and competition in both humans and nonhumans are discussed.

Journal Article↗
PubMed1995

Discounting of delayed rewards: Models of individual choice.

The present paper addresses the question of the form of the mathematical relation between the time until a delayed reward and its present value. Data are presented from an experiment in which subjects chose between hypothetical amounts of money available either immediately or after a delay (Green, Fry, & Myerson, 1994). Analyses of the behavior of individual young adults demonstrated that temporal discounting is better described by hyperbola-like functions than by exponential decay functions. For most individuals, the parameter that determines the rate of discounting varied inversely with amount. Raising the denominator of the discounting function to a power resulted in better descriptions of the data from most subjects. Two possible derivations of the temporal discounting function are proposed, a repeated choice model and an expected value model. These provide theoretical interpretations for amount-dependent discounting but amount-independent exponent parameters.

Journal Article↗
PubMed1995

Soft tissue sarcoma and non-Hodgkin's lymphoma in workers exposed to phenoxy herbicides, chlorophenols, and dioxins: two nested case-control studies.

We examined the effect of exposure to chemicals present in the production and spraying of phenoxy herbicides or chlorophenols in two nested case-control studies of soft tissue sarcoma and non-Hodgkin's lymphoma. Eleven sarcoma and 32 lymphoma cases occurring within an international cohort were matched for age, sex, and country of residence with 55 and 158 controls, respectively. Exposures to 21 chemicals or mixtures were estimated by three industrial hygienists who were blind to the subject's case-control status. Excess risk of soft tissue sarcoma was associated with exposure to any phenoxy herbicide [odds ratio (OR) = 10.3; 95% confidence interval (CI) = 1.2-91] and to each of the three major classes of phenoxy herbicides (2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, and 4-chloro-2-methylphenoxyacetic acid), to any polychlorinated dibenzodioxin or furan (OR = 5.6; 95% CI = 1.1-28), and to 2,3,7,8-tetrachlorodibenzo-p-dioxin (OR = 5.2; 95% CI = 0.85-32). Sarcoma risk was not associated with exposure to raw materials or other process chemicals. In the non-Hodgkin's lymphoma study, associations were generally weaker than those found in the study on sarcoma. These findings indicate that workers exposed to phenoxy herbicides and their contaminants are at a higher risk of soft tissue sarcoma.

Case-Control Studies↗
PubMed1995

Generalized elastolysis (cutis laxa): case study illustrating associated medical and surgical conditions.

Cutis laxa is grouped with the other hyperelastic skin conditions, but it shows almost total lack of skin elasticity. Numerous other medical and surgical conditions may coexist with the skin problem, since it is a generalized affliction of the supporting connective tissues. Our patient had cutis laxa proved by skin biopsy. All surgical procedures were done without any wound complications. He had many associated medical conditions and so served as an excellent opportunity to review the condition of cutis laxa.

Aged↗
PubMed1994

Characterization of an in vitro-selected RNA ligand to the HIV-1 Rev protein.

A small RNA ligand with high affinity for the HIV-1 Rev protein, generated by the SELEX in vitro evolution method, was used in a series of chemical modification studies to aid in determining the secondary structure of the ligand, to detect which modifications interfere with the binding of the ligand to Rev, and to find those modifiable groups that are protected from attack when bound to the Rev protein. This SELEX RNA ligand, like the high-affinity binding site of the Rev-responsive element, seems to bind the Rev protein within or along the major groove. There are two major regions of the RNA that interact with the Rev protein, and these regions appear to be close in space. Additionally, this high-affinity ligand has been used as the basis for an additional "biased randomization" SELEX procedure, in an effort to gain comprehensive information on the RNA sequences and structural elements necessary for efficient binding to the Rev protein. This complementary experimental approach supports the structural conclusions of our chemical modification data.

Base Composition↗
PubMed1994

Flow cytometry as a prognostic predictor in gastric linitis plastica.

UNLABELLED: Gastric linitis plastica (GLP) is a diffusely infiltrating carcinoma of the stomach that is usually diagnosed in an advanced stage and associated with poor prognosis. Recent studies to evaluate ploidy of these tumors are not conclusive. We undertook a retrospective study of 43 surgically treated patients with GLP (27 males, 16 females, mean age 65 years) to see if ploidy could be used to predict outcome. Flow cytometric DNA analysis was performed on paraffin-embedded tissue using the modified Hedley technique. Mean follow-up interval was 11 months (1-72 months) with 18 (42%) alive at end of study. The remaining 25 (58%) died with a mean survival of 7 months. Lymph node status was positive in 31 (70%) and negative in 12 (30%) of patients. Twenty-nine (67%) of tumors were diploid; 14 (33%) were aneuploid. Statistical analysis revealed overall survival correlated significantly (P = 0.04) only with lymph node status. Diploid tumors had 18 (60%) positive and 11 (40%) negative lymph nodes, whereas aneuploid tumors had 13 (93%) positive and 1 (7%) negative nodes. DNA content correlated significantly (P = 0.05) with lymph node status, but not with overall survival. Tumors with positive lymph nodes were 18 (51%) diploid and 13 (42%) aneuploid; tumors with negative nodes were 11 (92%) diploid and 1 (8%) aneuploid. CONCLUSIONS: The majority of GLP tumors manifest diploid characteristics, and the presence or absence of lymph node metastasis is a major determinant in overall survival.

Adult↗
PubMed1994

Touch and visualisation to facilitate a therapeutic relationship in an intensive care unit--a personal experience.

This paper describes how the nature of touch was explored and utilised in nursing practice to promote a therapeutic relationship between nurse and client in an intensive care setting. It explains how this, and other complementary therapies such as visualisation and relaxation techniques, were used to facilitate a counselling situation, and also to effect the resolution of acute anxiety as an alternative to the traditional allopathic approach.

Adolescent↗
PubMed1994

Comparability of naevus counts between and within examiners, and comparison with computer image analysis.

In the course of an investigation of melanocytic naevus development in Queensland, Australia, whole-body naevus counts of 66 adolescents were performed separately by two nurse examiners on two occasions on average 4 weeks apart. There was good agreement between the two examiners for counts of total naevi on the whole body (intra-class correlation coefficient = 0.96) and at selected subsites (face, neck, back, upper arms, lower arms). Agreement was lower when raised naevi only were counted (0.83). Intra-examiner repeatability was high for both nurses, particularly for the more experienced examiner (intra-class correlation coefficients = 0.98 and 0.91 for total naevi on the whole body), and was consistently better when all naevi were counted rather than naevi of a particular size. Independent counts of naevi on the back using a computer imaging technique were reproducible (intra-class correlation coefficient = 0.92), but showed only moderate agreement with counts by the nurse examiners. Overall, these results demonstrate high comparability of naevus counts between and within similarly trained examiners. They do not support the common practice in epidemiological studies of restricting counts to naevi larger than 2 mm, or of counting raised naevi only.

Adolescent↗
PubMed1994

Tobacco use among American adolescents: geographic and demographic variations.

A previous national study indicated that the South dominated other regions of the United States in tobacco use. Using the results of the Teenage Attitudes and Practices Survey conducted by the National Center for Health Statistics, we examined the geographic and demographic differences of tobacco use among US adolescents. The sample consisted of teenagers in grades 7 through 12 nationwide (N = 6,599). Data were collected through telephone interviewing. The variables included demographics and measures of smoking or use of smokeless tobacco (chewing tobacco/snuff). Results indicated that the overall prevalence rate for smokeless tobacco use was 4.44%, but in the South it was 6.38%. The overall smoking prevalence rate was 13.31%, with no substantial difference among regions. Demographic variables such as sex, ethnicity, education, and poverty levels were also related to tobacco use prevalence. These geographic and demographic variations in tobacco use help target specific regions and populations in greatest need of intervention programs.

Adolescent↗
PubMed1994

Naevi in schoolchildren in Scotland and Australia.

To test the hypothesis that children living in subtropical and tropical environments have more naevi than those of similar ethnicity living in temperature countries, a comparative study of melanocytic naevi in 111 schoolchildren from Brisbane, Australia, and 222 from Glasgow, Scotland, was carried out. All children were aged 13-15 years, of European ancestry, and had spent most of their lives at latitudes of less than 30 degrees S (Australia) or greater than 30 degrees N (Scotland). Using an identical protocol, all naevi of 2 mm or more in diameter occurring on the right arm were counted by either a highly experienced research nurse in Brisbane, or a dermatologist in Glasgow. Hair and eye colour, and facial freckling, were assessed by the examiner, and axillary skin colour of children in both cities was measured using the same reflectance spectrophotometer. Children in Brisbane had significantly more naevi than those in Glasgow (P < 0.05), after adjusting for complexion variables. The difference in the geometric mean number of naevi on the arm was much greater among boys (7.7 vs. 4.4, in Brisbane and Glasgow, respectively) than among girls (7.3 vs. 6.7). This has parallels with the sex differences in melanoma at later ages in the two countries. Besides country of residence, freckles and innate skin colour were the most significant predictors of large numbers of naevi, whereas red hair had a significant protective effect. Overall, these data on prevalence of naevi in children from contrasting environments provide some evidence in support of the theory that naevus development is related to the level of sun exposure in childhood and adolescence.

Adolescent↗