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Biomedical subjects

L Sheldon

Publications and source records attributed to L Sheldon.

At least 19 recordsLinked to original sources
PubMed2001

The influence of human activity patterns on personal PM exposure: a comparative analysis of filter-based and continuous particle measurements.

Particulate matter (PM) exposure data from the U.S. Environmental Protection Agency (EPA)-sponsored 1998 Baltimore and 1999 Fresno PM exposure studies were analyzed to identify important microenvironments and activities that may lead to increased particle exposure for select elderly (>65 years old) subjects. Integrated 24-hr filter-based PM2.5 or PM10 mass measurements [using Personal Environmental Monitors (PEMs)] included personal measurements, indoor and outdoor residential measurements, and measurements at a central indoor site and a community monitoring site. A subset of the participants in each study wore passive nephelometers that continuously measured (1-min averaging time) particles ranging in size from 0.1 to approximately 10 microm. Significant activities and locations were identified by a statistical mixed model (p < 0.01) for each study population based on the measured PM2.5 or PM10 mass and time activity data. Elevated PM concentrations were associated with traveling (car or bus), commercial locations (store, office, mall, etc.), restaurants, and working. The modeled results were compared to continuous PM concentrations determined by the nephelometers while participants were in these locations. Overall, the nephelometer data agreed within 6% of the modeled PM2.5 results for the Baltimore participants and within approximately 20% for the Fresno participants (variability was due to zero drift associated with the nephelometer). The nephelometer did not agree as well with the PM10 mass measurements, most likely because the nephelometer optimally responds to fine particles (0.3-2 microm). Approximately one-half (54 +/- 31%; mean +/- standard deviation from both studies) of the average daily PM2.5 exposure occurred inside residences, where the participants spent an average of 83 +/- 10% of their time. These data also showed that a significant portion of PM2.5 exposure occurred in locations where participants spent only 4-13% of their time.

Activities of Daily Living↗
PubMed2000

Monozygotic boys with fragile X syndrome.

Monozygotic twin boys with fragile X syndrome underwent thorough genetic, psychiatric, neurological, and language evaluations at 10 years of age. They both demonstrated physical features, speech and language difficulties, social problems, and attentional deficits that characterize the behavioural phenotype of fragile X syndrome. Despite identical genetic constitutions, there were important developmental and behavioural heterogeneities. Twin A showed less social interaction and symbolic play and more speech and language dysfunction than twin B. Twin A also had significantly larger caudate volumes. It is suggested that the Xq27.3 anomaly may not be sufficient to account for all the behavioural phenotypic and neuroanatomical features of fragile X syndrome.

Attention Deficit Disorder with Hyperactivity↗
PubMed1997

Hospitalising children: a review of the effects.

In this literature review, the author examines the effects of hospitalisation on children. In particular, the case for having a parent present throughout the admission is discussed, along with evidence for encouraging parents to become more involved in actual care.

Adult↗
PubMed1997

Correlations among human blood levels of specific PCB congeners and implications for epidemiologic studies.

Specific congeners of PCBs may differ with respect to their human health risks. For epidemiologic studies, however, measuring levels of specific congeners--as compared with estimating the concentration of total PCBs present, may be of limited value if levels of specific congeners are highly correlated. We examined the correlations among levels of specific congeners in three groups: controls from a case-control study of breast cancer in North Carolina and two groups from Wisconsin with exposure to fish from contaminated waters. Levels of specific congeners were, in general, highly correlated (Pearson r > 0.80). However, the level of congener 180, a heptachlorobiphenyl, tended to be less correlated with levels of lower-chlorinated biphenyls. Among the implications of these findings are that measurement of a select group of congeners may yield essentially the same information as measurement of a large panel, and may be more cost efficient.

Adult↗
PubMed1997

Do doctors know when their patients don't? A survey of doctor-patient communication in lung cancer.

OBJECTIVES: a) To determine how much patients with recently diagnosed lung cancer know about their illness and its treatment, and b) to find out if doctors know what their patients know and what they don't. PATIENTS AND METHODS: One hundred patients with recently diagnosed lung cancer, who were undergoing radiotherapy or chemotherapy, were interviewed to determine their view of their diagnosis, the extent of the cancer, the intent of treatment, and the risks and benefits of treatment. Their attending physicians' view were elicited contemporaneously, using a self-administered questionnaire. The principle outcome measure of the study was the level of agreement between the views of the patients and the doctors about the disease, the treatment, and the prognosis. Concordance between doctors' and patients' views was expressed in terms of percentage agreement, and Kappa (kappa). RESULTS: Ninety-nine percent of the patients knew that they had lung cancer. Sixty-four percent (64%) agreed with their doctor about the extent of the disease (kappa = 0.48). Most of those who disagreed underestimated the extent of their cancer. Seventy-two percent (72%) agreed with their doctor about the intent of treatment (kappa = 0.49). Thirty-six percent (36%) agreed with their doctors about their probability of cure, (kappa = 0.17): most of those who disagreed systematically overestimated it. Sixty-eight patients were receiving palliative treatment. Of these, 56% agreed with their doctor about the probability of symptomatic benefit (kappa = 0.42), but only 14% agreed with their doctor about the probability that the treatment would prolong life (kappa = 0.06). Doctors frequently failed to recognize their patients' misconceptions about the intent of treatment and the prognosis. CONCLUSION: Many patients did not understand their situation well enough to make a truly autonomous treatment decision, and their doctors often failed to recognize this.

Adult↗
PubMed1993

Aggression in the demented patient: a double-blind study of loxapine versus haloperidol.

Aggression is common in dementia, with devastating social consequences. While high or low potency neuroleptics are the usual treatment of choice, they have been shown to yield inconsistent behavioral improvement and significant iatrogenic disability. This double-blind study was undertaken with aggressive demented patients to assess the efficacy and safety of a mid-potency neuroleptic, loxapine, in comparison to the more commonly prescribed high potency drug, haloperidol. Using an optimizing dosage regime, the outcome variables studied were aggression frequency and the number and nature of emergent side effects. Results demonstrated no significant difference regarding efficacy, but significantly fewer side effects with loxapine administration. The clinical and theoretical implications of these findings are discussed.

Aged↗
PubMed1991

Isolation of a cDNA for HSF2: evidence for two heat shock factor genes in humans.

The heat shock response is transcriptionally regulated by an evolutionarily conserved protein termed heat shock factor (HSF). We report the purification to homogeneity and the partial peptide sequence of HSF from HeLa cells. The peptide sequence was used to isolate a human cDNA with a predicted open reading frame that has homology to the DNA binding domains of both Saccharomyces cerevisiae and Drosophila HSFs. The cDNA directs the synthesis of a protein that binds to the heat shock element with specificity identical to HeLa HSF and stimulates transcription from a heat shock promoter. The expressed protein cross-reacts with anti-HSF antibodies. Surprisingly, however, this cDNA does not encode all of the peptides obtained from purified HeLa HSF. These peptides are encoded by a distinct human cDNA, HSF1, described by Rabindran et al. [Rabindran, S. K., Giorgi, G., Clos, J. & Wu, C. (1991) Proc. Natl. Acad. Sci. USA 88, 6906-6910.] It therefore appears that there is a human heat shock factor gene family and that at least two separate but related HSF proteins regulate the stress response in humans.

Amino Acid Sequence↗
PubMed1987

The TEAM (Total Exposure Assessment Methodology) Study: personal exposures to toxic substances in air, drinking water, and breath of 400 residents of New Jersey, North Carolina, and North Dakota.

EPA's TEAM Study has measured exposures to 20 volatile organic compounds in personal air, outdoor air, drinking water, and breath of approximately 400 residents of New Jersey, North Carolina, and North Dakota. All residents were selected by a probability sampling scheme to represent 128,000 inhabitants of Elizabeth and Bayonne, New Jersey, 131,000 residents of Greensboro, North Carolina, and 7000 residents of Devils Lake, North Dakota. Participants carried a personal monitor to collect two 12-hr air samples and gave a breath sample at the end of the day. Two consecutive 12-hr outdoor air samples were also collected on identical Tenax cartridges in the backyards of some of the participants. About 5000 samples were collected, of which 1500 were quality control samples. Ten compounds were often present in personal air and breath samples at all locations. Personal exposures were consistently higher than outdoor concentrations for these chemicals and were sometimes 10 times the outdoor concentrations. Indoor sources appeared to be responsible for much of the difference. Breath concentrations also often exceeded outdoor concentrations and correlated more strongly with personal exposures than with outdoor concentrations. Some activities (smoking, visiting dry cleaners or service stations) and occupations (chemical, paint, and plastics plants) were associated with significantly elevated exposures and breath levels for certain toxic chemicals. Homes with smokers had significantly increased benzene and styrene levels in indoor air. Residence near major point sources did not affect exposure.

Air Pollutants, Occupational↗
PubMed1982

Increased level of translatable collagenase messenger ribonucleic acid in rabbit synovial fibroblasts treated with phorbol myristate acetate or crystals of monosodium urate monohydrate.

We studied mechanisms governing production of the neutral proteinase collagenase by synovial cells. We used a model system of monolayer cultures of rabbit synovial fibroblasts stimulated to produce collagenase by treatment with phorbol myristate acetate or crystals of monosodium urate monohydrate. mRNAs from these and untreated cells were translated in a wheat germ cell-free system. Collagenase was not present in the culture medium or in the in vitro translation products of mRNA from untreated cells but was present in both the medium and translation products of stimulated cells, as analyzed by gel electrophoresis and immunoprecipitation with monospecific antibody. Induction of collagenase was prevented by treatment of the cells with alpha-amanitin (2 mug/ mL), an inhibitor of mRNA synthesis. We have concluded that the induction of collagenase synthesis by either phorbol myristate acetate or urate crystals is due to an increased level of translatable mRNA.

Amanitins↗
PubMed1982

Brain water and electrolytes in response to respiratory acidosis and brain edema in the mutant mouse, jimpy.

Compared to littermate controls, unstressed Jimpy mice have higher brain water, sodium, potassium and chloride contents and lower carbonic anhydrase activity. When stressed by CO2 to produce a respiratory acidosis or by injection of distilled water to produce brain edema, the Jimpy mouse brain has water and ionic responses essentially like those in controls.

Acidosis, Respiratory↗