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Biomedical subjects

C Lewis

Publications and source records attributed to C Lewis.

At least 199 records · Page 11Linked to original sources
PubMed1991

Factors underlying illusory self-assessment of driving skill in males and females.

While it is known that drivers as a group rate their skills as better than the average, the mechanism underlying this illusion is unclear. It is possible, for example, that it is due either to a "positive-self" or "negative-other" bias. A test of these alternative hypotheses revealed that judgments are consistent with a "positive-self" bias. An attempt was made to determine whether the illusion was present in all areas of driving skill or whether there were specific components where the illusion was absent. For men, the bias was present in all the driving components examined. For women, there were several areas where they rated themselves less positively than the men, and four areas where they showed no evidence of any bias. When the effects of driving experience were statistically controlled for, however, these sex differences were found to be substantially reduced.

Adolescent↗
PubMed1991

Advances in drug delivery and targeting.

This review covers a variety of techniques aimed at improving the specificity of delivery of both biologic and cytotoxic agents to tumor tissue while sparing normal tissue. The major areas reported on include further attempts to increase the ability of monoclonal antibodies, both conjugated and unconjugated, to target tumor tissue. It also examines the early clinical trials of liposomes as carriers of both biologics and cytotoxics and the potential problems of this modality. A number of studies in the area of regional drug delivery, including intraperitoneal, intravesical, intra-arterial, and intratumor, highlight the many clinical problems still to be resolved. Improved targeting of antitumor agents to sites of malignant disease appears likely over the next decade judging by the recent developments we review. Although much clinical and laboratory research will be required to achieve this goal, the likely directions appear to be established.

Antibodies, Monoclonal↗
PubMed1991

Quantifying serum antibody class and subclass responses by enzyme immunoassay in humidifier-related disease.

Antibody activity in the major classes and IgG subclasses against antigens in factory humidifier water was quantified by enzyme immunoassay (EIA) in 88 subjects who were exposed at work to the output from these contaminated humidifiers. Those with work-related symptoms had significantly higher mean titres than those who were symptom free, although values overlapped. The individuals with the highest IgG antibody titres also had the highest titres of IgM and IgA antibody, and these parameters did not discriminate between those with and without symptoms any better than the IgG titre. This was also true for the IgG subclasses where activity was predominantly measured in IgG1. Quantifying the IgG antibody allowed us to demonstrate a significant correlation with years of work exposure (P less than 0.001). There was no significant association between antibody and cigarette smoking, as assessed by smoking history and confirmed objectively by serum cotinine levels. There was a significant correlation with total IgG level (P less than 0.001) suggesting that a non-specific immune enhancement may accompany the specific response. The antibody titres were followed up to 3 years after modification of the humidification systems, and during this time symptoms resolved and the antibody levels progressively fell to undetectable levels. The EIA was adapted to measure antigen at nanogram levels thus providing a rapid test for screening of humidifer water as well as a technique that may help identify the nature of the antigens involved.

Air Conditioning↗
PubMed1991

Mobile versus fixed site lithotripsy.

The efficacy of a mobile Dornier HM4 lithotriptor, was compared with that of a fixed site Siemens Lithostar. A total of 115 calculi in 98 patients were treated, 55 on the mobile Dornier and 60 on the Lithostar. The groups were similar except for stone size, the mean of the Lithostar group being 11 mm compared with 7.7 mm in the Dornier group. Fragmentation rates were not significantly different, 88% and 75% on the mobile and fixed site machines, respectively and, at 3 months follow-up 66% and 46% were stone free or with fragments of less than 2 mm. There were no serious complications, and the incidence of mild complications was similar in the two groups. We conclude that the mobile Dornier HM4 is an effective lithotriptor and can offer several advantages over fixed site machines.

Female↗
PubMed1990

Human granulocyte-macrophage colony-stimulating factor plus phorbol myristate acetate stimulate a promyelocytic cell line to produce an IL-1 inhibitor.

We recently described an IL-1 inhibitor found in urine of febrile patients. It is a 26-kDa glycoprotein that acts by blocking the binding of IL-1 to its receptor. In a search for a cell source for the urinary IL-1 inhibitor, we tested three promyelocytic cell lines, H-161, AML-193, and HL-60, for their ability to produce this protein. Under normal culture conditions none of these cell lines produce detectable IL-1 inhibitory activity. The H-161 cells were treated with differentiation-inducing agents, i.e., sodium butyrate, hemin, retinoic acid, DMSO, vitamin D3, and PMA alone or in combination with IL-1 alpha, IL-2, IL-3, IL-4, IL-5, IL-6, TNF-alpha, IFN-gamma, granulocyte-CSF, macrophage-CSF, granulocyte/macrophage-CSF (GM-CSF), and Con A and tested for the production of IL-1 inhibitor. Production of IL-1 inhibitor was detected in cell supernatant, when H-161 cells were differentiated to adherent macrophage-like cells under the influence of PMA followed by a second signal provided by GM-CSF. Treatment of the other two cell lines, AML-193 and HL-60, with PMA plus GM-CSF also yielded similar IL-1 inhibitor protein. Partial purified H-161-derived IL-1 inhibitor showed specific binding to IL-1R-bearing cells and blocked the binding of IL-1 to its receptor and is thus similar to the urinary-derived molecule. We conclude the GM-CSF provides a signal to adherent macrophage-like cells to become "inhibitory macrophages" and to produce a competitive inhibitor of IL-1.

Colony-Stimulating Factors↗
PubMed1990

School-based primary prevention: what is an effective program?

Our model makes us pessimistic about quick-fixes. Short-term, narrowly focused programs designed to increase children's knowledge or some limited aspect of their competence are unlikely to be effective in preventing AIDS. Our model suggests that what protects a child from AIDS is not knowledge or isolated social skills but rather the quality of bonds to school, family, and other socialization agents. Ultimately, the school-based route to prevention of AIDS will work only if schools are effective socialization agents: effective in meeting children's needs for autonomy, belonging, and competence, and thereby in helping children build the motivation and social competence they will need to avoid many kinds of high-risk behavior over many years.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Monoclonal antibodies reacting with the interleukin 1 receptor define a multi-molecular complex.

By sequential immunization with a variety of different interleukin (IL) 1 receptor (IL 1R)-bearing cells and by generating a large number of clones from a single fusion experiment, we have managed to produce two monoclonal antibodies which react with the lymphocyte IL 1R. The antibodies also react with the mouse fibroblast line, 3T3, but we have not yet defined their reactivity with cells carrying low-affinity receptors. Immunoprecipitation allows the IL 1R to be isolated from EL4 6.1 cell membrane preparations and shows that the IL 1R exists as a complex. The antibodies clearly interfere with IL 1 responses both in vitro and in vivo. These are the first anti-mouse IL 1R antibodies to be described which clearly and profoundly affect the immune response.

Animals↗
PubMed1990

Phase I and pharmacokinetic study of intraperitoneal thioTEPA in patients with ovarian cancer.

A total of 15 patients with residual ovarian cancer confined to the peritoneal cavity after first-line systemic chemotherapy were treated with triethylene-thiophosphoramide (thioTEPA) in a phase I study. A total of 50 courses of thioTEPA were given intraperitoneally in doses ranging from 30 to 80 mg/m2. The dose limiting toxicity was myelosuppression, which occurred at 80 mg/m2 and was frequently prolonged. Short-lived nausea and vomiting was easily controlled, and there was no local toxicity. Three patients remain free of disease progression at 6, 6 and 12 months. ThioTEPA concentrations were measured by gas chromatography. Peritoneal fluid concentrations declined rapidly in a first-order fashion, with a half-life of 0.96 +/- 0.1 h. A mean of 93% of the drug was absorbed during the 4-h dwell time. Peak plasma levels were achieved 30-60 min after drug instillation and were substantially lower than corresponding peritoneal levels. A pharmacokinetic advantage for intraperitoneal delivery was detected for peak drug concentration (24.9 +/- 8.5) and AUC (9.2 +/- 4.8). Based on this study, the recommended dose for intraperitoneal thioTEPA is 60 mg/m2 every 3-4 weeks. However, the rapid absorption of this drug from the peritoneum, secondary to thioTEPA's small molecular weight and lipophilic nature, suggests that it has only a limited role in intraperitoneal therapy.

Adult↗
PubMed1990

The effect of vitamin E on lipid peroxidation in the copper-deficient rat.

The present study was designed to determine whether the supplementation of vitamin E in the copper-deficient diet would ameliorate the severity of copper deficiency in fructose-fed rats. Lipid peroxidation was measured in the livers and hearts of rats fed a copper-deficient diet (0.6 microg Cu/g) containing 62% fructose with adequate vitamin E (0.1 g/kg diet) or supplemented with vitamin E (1.0 g/kg diet). Hepatic lipid peroxidation was significantly reduced by vitamin E supplementation compared with the unsupplemented adequate rats. In contrast, myocardial lipid peroxidation was unaffected by the level of vitamin E. Regardless of vitamin E supplementation, all copper-deficient rats exhibited severe signs of copper deficiency, and some of the vitamin E-supplemented rats died of this deficiency. These findings suggest that although vitamin E provided protection against peroxidation in the liver, it did not protect the animals against the severity of copper deficiency induced by fructose consumption.

Journal Article↗
PubMed1990

Patterns of fecal coliform contamination in day-care centers.

During a six-month period, on four separate occasions, six licensed day-care centers had cultures taken from environmental surfaces as well as the hands of children and teachers. Fecal coliforms were recovered from 64 (9.5%) of the 675 surfaces sampled. Recovery rate was not influenced by a center's socioeconomic status, time of year, or presence of children who were not toilet trained. Recovery rates did differ significantly in different areas, with the kitchen showing a relatively high recovery rate (19%), and toys and toilets showing remarkably low rates (2% and 4%). Centers with formal hand-washing procedures had lower recovery rates than those without such practices. We also demonstrated a high recovery rate from hands of staff (16%); 6% of children had positive cultures. Contamination of hands and classroom objects is a potential source for the transmission of enteric diseases for children in day-care centers. A program directed at reducing contamination would be important in preventing the spread of diarrheal illness.

Child↗
PubMed1990

Three-year-olds' problems with false belief: conceptual deficit or linguistic artifact?

Researchers are divided over whether young children understand other people's minds. This study reexamines the main technique used to show a basic inability in 3-year-olds to make judgments about a person's thoughts when that person's knowledge happens to be false. 131 children, aged 3, 3 1/2, and 4, were shown the real, unexpected contents of a chocolate box and were required to say what a friend would think was in it and what their own previous expectations had been. Success in this task was compared between the 3 age groups and also according to the specificity of questions asked. It was found, in contrast to previous findings, that test questions that are temporally specific and syntactically straightforward enable most 3-year-olds to attribute false beliefs to others. These results suggest that 3-year-olds' access to information about others' mental states is bounded by the linguistic demands placed upon them, but long before their fourth birthday children have some understanding of others' mind.

Child, Preschool↗
PubMed1990

Birth and fertility rates by education: 1980 and 1985.

Birth and fertility rates by educational attainment of mother are shown for the United States, geographic regions and divisions, and States for 1980 and 1985. The report focuses on differentials in childbearing among educational attainment groups and changes in fertility levels during the period, particularly for well-educated older mothers. The information presented is derived from entries on live-birth certificates from 47 states and the District of Columbia.

Adolescent↗
PubMed1989

Women in academic medicine. Combining career and family.

We conducted a national survey to explore how women in academic medicine balance career and family responsibilities. A questionnaire was mailed to all women 50 years of age and under who held full-time appointments in departments of medicine (n = 862), as listed in the faculty roster of the Association of American Medical Colleges. The survey included questions about childbearing and child rearing, attitudes about personal and professional issues, and role models. Of the 694 questionnaires that were delivered, over 80 percent were completed (n = 558). The mean age of the respondents was 38.1 years, and 63 percent had children. The 350 mothers had a mean of 1.9 children; only 3 had 4 or more children. Approximately half the respondents with children had their first child after completing medical training (mean age, 30.6 years), and they were absent from work for a median of 6 weeks post partum; 72 percent took no time off before labor and delivery, and 83 percent were back at work within 12 weeks. The majority were satisfied with their decision to have children and with their careers, despite the fact that 78 percent believed that their career progress had been slowed or markedly slowed by their having had children. We conclude that it is possible for women to combine motherhood with a fulfilling career in academic medicine, but it is difficult, and most such women believe that motherhood slows the progress of their careers.

Adult↗
PubMed1989

Phase I clinical and pharmacokinetic study of LY 195448.

LY 195448 is a phenethanolamine that has shown anti-tumour activity in a range of murine tumour models, although its mechanism of action is unknown. Pre-clinical studies have indicated the absence of "standard" side effects such as myelosuppression and gastrointestinal toxicity. The present phase I trial was carried out in nine patients at doses ranging up to 133 mg/m2. The major toxicities up to that dose were mild, reversible hypotension, tachycardia and tremor. No haematological or biochemical toxicity was observed. Murine pharmacokinetics were assessed at a dose level that was effective in experimental tumours and compared with human pharmacokinetic parameters derived from this study. The results indicated the clinical possibility of reaching peak drug levels associated with experimental activity. However, no responses were seen at the doses used. This study was terminated prior to its completion due to an unexplained loss of activity against murine tumours since September 1987. No significant loss of the in vitro anti-mitotic activity originally reported by Boder et al. [3] was observed. Possible reasons for the apparent loss of in vivo activity have been intensively investigated, but no cause has been determined. Therefore, clinical trials with LY 195448 have been discontinued.

Adult↗
PubMed1989

Nuclear worries of Canadian youth: replication and extension.

A national survey of Canadian adolescents assessed concern, anxiety, and sources of information about the threat of nuclear war. Results indicated few geographical or gender differences in overall levels of concern, although females were more likely to admit fear and anxiety, and students with activist parents showed more concern. Family ranked below all media as a source of information.

Adolescent↗
PubMed1989

Typographic influences on reading.

The research reported here comprises an empirical investigation of the phenomenon of typographic allusion. In a preliminary study, subjects rated the perceptual qualities possessed by different typefaces (e.g. heavy-light, fast-slow). The results indicated that subjects agreed as to typeface characteristics and that typefaces were distinguished by such qualities. In Expt 1, subjects undertook a speeded decision task in which they responded according to which one of four adjectives appeared tachistoscopically. Each word appeared in a typeface whose qualities were either consistent or inconsistent with its meaning. Reaction times for inconsistent stimuli were significantly slower than those for consistent trials. In preparation for Expt 2, the same rating procedure was used to elicit subjects' judgements of the attributes of different animals. Subjects agreed as to animals' qualities and such qualities reliably distinguished between the animals. The names of these animals were then used as targets in a binary decision task and each one appeared in a typeface possessing qualities which were either congruent or incongruent with those of the animal. Subjects responded according to whether they considered the animal presented on each trial to be heavy or light, or fast or slow moving. Responses on trials in which the animal and typeface possessed conflicting attributes were significantly slower than responses when animal and typeface qualities were congruent. These results are discussed in relation to current views regarding the processing of written English. We argue that typographic features of words are able to access a semantic code and that this code can interact with the derivation of a linguistic code specifying a word's meaning and/or with post-lexical access decision processes.

Decision Making↗
PubMed1989

Climate, intermittent humidification, and humidifier fever.

Two summer outbreaks of humidifier fever (HF) are described in a microprocessor factory (factory A) and a printing factory (factory B). The air in each factory was humidified intermittently and controlled by present humidistats operating to maintain a relative humidity of 45% by an air handler incorporating a spray humidifier in factory A and two ceiling mounted spray humidifiers in factory B. Questionnaire data from each workforce suggested that although symptoms apparently occurred most commonly in both factories on return from holiday (41/57, 71.9%), many subjects (24/40, 60%) in factory A also had intermittent symptoms of ill defined periodicity for some time before the disorder was recognised. Similar intermittent symptoms with no discernible pattern occurred in factory B in a smaller number of subjects (4/17, 23.5%), all of whom were night or rotating shift workers. Both episodes of humidifier fever after return from summer holiday developed when nocturnal air temperatures were unseasonably low; not on the day of return to work but two days later (factory A) and one day later (factory B). Symptoms were most common in most workers who had circulating serum IgG antibody measured by ELISA to humidifier sludge in factory B (14/17, 82.9%) but were most common in IgG antibody negative subjects in factory A (27/40, 67.5%). A more classic form of humidifier fever redeveloped in factory B during winter when meteorological recordings suggested that humidification of intake air was more continuous. Humidifier fever in winter may have been the major influence on the formulation of the symptom pattern thought to be relevant for recognition of the disorder. A form of the illness, however, can occur during the summer which is camouflaged by intermittent humidification when the symptoms appear to be more closely associated with cool nocturnal air intake and unrelated to the pattern of attendance at work.

Air Conditioning↗