Doses from radon and its decay products to children

This paper considers doses from radon and decay products when inhaled or ingested by one year old infants and by ten year old children. Doses from decay products deposited on skin are also discussed. For inhalation and ingestion, the general pattern of doses to organs is broadly similar to that in adults. Much the largest doses are received by the organ of intake (respiratory tract and stomach respectively). Otherwise, tissues with higher fat content tend to receive somewhat higher doses from radon gas than other tissues. Dose coefficients (dose per unit intake factors) for children are generally larger than those for adults. However, total annual doses are more similar across the age groups because of smaller intakes of air and water by children. Radon decay products deposited on skin may be able to induce skin cancer. However, the location of the sensitive cells is not known with certainty and they may lie too deep to receive significant dose. If they are irradiated, it is likely that doses to children would be larger than for adults. The radiological significance of doses to children is discussed.

Molecular Evolution of Antibody Affinity for Sensitive Detection of Botulinum Neurotoxin Type A

Botulism is caused by botulinum neurotoxin (BoNT), the most poisonous substance known. Potential use of BoNT as a biothreat agent has made development of sensitive assays for toxin detection and potent antitoxin for treatment of intoxication a high priority. To improve detection and treatment of botulism, molecular evolution and yeast display were used to increase the affinity of two neutralizing single chain Fv (scFv) antibodies binding BoNT serotype A (BoNT/A). Selection of yeast displayed scFv libraries was performed using methods to select for both increased association rate constant (k(on)) and decreased dissociation rate constants (k(off)). A single cycle of error prone mutagenesis increased the affinity of the 3D12 scFv 45-fold from a K(D) of 9.43x10(-10)M to a K(D) of 2.1x10(-11)M. Affinity of the HuC25 scFv was increased 37-fold from 8.44x10(-10)M to 2.26x10(-11)M using libraries constructed by both random and site directed mutagenesis. scFv variable region genes were used to construct IgG for use in detection assays and in vivo neutralization studies. While IgG had the same relative increases in affinity as scFv, (35-fold and 81-fold, respectively, for 3D12 and HuC25) higher solution equilibrium binding constants were observed for the IgG, with the 3D12 K(D) increasing from 6.07x10(-11)M to 1.71x10(-12)M and the HuC25 K(D) increasing from 4.51x10(-11)M to 5.54x10(-13)M. Affinity increased due to both an increase in k(on), as well as slowing of k(off). Higher affinity antibodies had increased sensitivity, allowing detection of BoNT/A at concentrations as low as 1x10(-13)M. The antibodies will also allow testing of the role of affinity in in vivo toxin neutralization and could lead to the generation of more potent antitoxin.

The American Society of Clinical Oncology program to improve end-of-life care

Too few cancer patients have optimal care at the end of life, as measured by unrelieved pain, death in a setting other than home, and uncoordinated care. The American Society of Clinical Oncology (ASCO), as the largest professional society whose members care for most cancer patients in the United States, has begun an initiative to improve end-of-life care. Educational programs for ASCO members have been started at the national level. A Task Force on End of Life Care was created to study the current state of end-of-life care, barriers to improved end-of-life care, and what ASCO can do to improve end-of-life care. A member-wide survey has been completed to assess, from the professional's perspective, the current state of and barriers to end-of-life care. Specific sections of the Task Force will address hospice care, physician- assisted suicide, clinical barriers, economic barriers, research initiatives, educational deficiencies, and quality of care at the end of life. Improvements in end-of-life care can be made if the current deficiencies are noted, barriers ascertained, and specific solutions found. Professional societies have both the interest and responsibility to improve end-of-life care.

An implantable drug delivery system (IDDS) for refractory cancer pain provides sustained pain control, less drug-related toxicity, and possibly better survival compared with comprehensive medical management (CMM)

BACKGROUND

The randomized clinical trial of implantable drug delivery systems (IDDS) plus comprehensive medical management (CMM) versus CMM alone showed better clinical success at 4 weeks for IDDS patients. This 'as treated' analysis assessed if improvements in pain control, drug toxicity and survival were maintained over time.

PATIENTS AND METHODS

We compared those who received IDDS with those who did not receive IDDS (non-IDDS). All patients had Visual Analogue Scores (VAS) for pain > or =5/10 on at least 200 mg morphine or equivalent daily.

RESULTS

At 4 weeks, 46 of 52 (88.5%) IDDS patients achieved clinical success compared with 65 of 91 (71.4%; P=0.02) non-IDDS patients, and more often achieved > or =20% reduction in both pain VAS and toxicity [35 of 52 (67.3%) versus 33 of 91 patients (36.3%); P=0.0003]. By 12 weeks, 47 of 57 (82.5%) IDDS patients had clinical success compared with 35 of 45 (77.8%; P=0.55) non-IDDS patients, and more often had a > or =20% reduction in both pain VAS and toxicity [33 of 57 (57.9%) versus 15 of 45 patients (33.3%); P=0.01]. At 12 weeks the IDDS VAS pain scores decreased from 7.81 to 3.89 (47% reduction) compared with 7.21 to 4.53 for non-IDDS patients (42% reduction; P=0.23). The 12 week drug toxicity scores for IDDS patients decreased from 6.68 to 2.30 (66% reduction), and for non-IDDS patients from 6.73 to 4.13 (37% reduction; P=0.01). All individual drug toxicities improved with IDDS at both 4 and 12 weeks. At 6 months, only 32% of the group randomized to CMM and who did not cross over to IDDS were alive, compared with 52%-59% for patients in those groups who received IDDS.

CONCLUSIONS

IDDS improved clinical success, reduced pain scores, relieved most toxicity of pain control drugs, and was associated with increased survival for the duration of this 6 month trial.

Cloning and characterization of a homologue of the alpha inhibitor of NF-κB in Rainbow trout (Oncorhynchus mykiss)

A homologue of IkappaBalpha, the alpha member of the IkappaB family of NF-kappaB inhibitors, was identified in a Rainbow trout suppression subtractive hybridization library enriched in sequences up-regulated in cultured leukocytes after lipopolysaccharide (LPS) and tumor necrosis factor alpha (TNFalpha) stimulation. The full-length cDNA was isolated and sequenced. The predicted amino acid sequence is 61.5% similar and 54% identical to human IkappaBalpha, while only 42% similar and 35% identical to IkappaBbeta, and 38% similar and 32% identical to IkappaBvarepsilon. Rainbow trout IkappaBalpha contains a central ankyrin repeat domain required for its interaction with NF-kappaB and a putative PEST-like sequence in the C-terminus. Expression of IkappaBalpha is up-regulated by LPS and TNFalpha treatment, two known activators of NF-kappaB, suggesting the existence of an autoregulatory loop in fish, as is the case for mammals. These results confirm the existence of the NF-kappaB signalling pathway in fish and suggest a similar functional interaction between IkappaBalpha and NF-kappaB.

Novel aspects of orbital fibroblast pathology

Orbital fibroblasts exhibit a unique phenotype including exaggerated responses to proinflammatory cytokines. We hypothesize that the unusual susceptability of these fibroblasts to molecular cues underlies the involvement of the orbit in Graves' ophthalmopathy. A number of attributes of orbital fibroblasts are reviewed in this article. In addition, we have found IgG circulating in patients with Graves' disease that binds and activates the insulin-like growth factor-1 receptor displayed on fibroblasts from many anatomic regions. Activation of this receptor leads to the expression of T-cell chemoattractants. Thus, fibroblast activation, and the resulting T-cell trafficking to connective tissue in Graves' disease may be systemic. The consequences of lymphocyte-derived cytokine action may differ vastly in the orbit and other tissues manifesting clinically obvious disease.

Commercial exploitation of transgenics

A series of examples of the application of recombinant nucleic acid technology to the production of transgenic organisms is presented. The review considers the distinct advantages of producing certain recombinant biomolecules in appropriate eucaryotic systems rather than in the traditional procaryotic ones. Gene therapy in humans and the production of transgenic animals and plants are discussed. Concerns about the inadvertant construction of new pathogens and ethical considerations about interfering with poorly understood ecosystems are addressed.

Unique properties of orbital connective tissue underlie its involvement in Graves' disease

Orbital connective tissue manifests Graves' disease through unknown pathogenic mechanisms. Currently there exists little insight into the identity of factors initiating and sustaining the inflammatory response and tissue remodeling associated with ophthalmopathy. We hypothesize that orbital fibroblasts represent cells with unusual phenotypes. They exhibit exaggerated responses to pro-inflammatory cytokines. Among these are inductions of prostaglandin E(2) and hyaluronan synthesis. Activation of fibroblasts occurs through the trafficking of lymphocytes and mast cells to the orbit and the local production of cytokines. In this brief article, we review some of the attributes of orbital fibroblasts and their interactions with immune cells that are currently believed to contribute to their role in the pathogenesis of Graves' disease.

Are the material properties and matrix composition of equine flexor and extensor tendons determined by their functions?

REASONS FOR PERFORMING STUDY

Injury to the superficial digital flexor tendon (SDFT) is common in competition horses. The SDFT contributes to locomotory efficiency by storing energy; such tendons have low safety margins. Tendons which merely position the limb, including the opposing common digital extensor tendon (CDET), are rarely injured. The current failure of strategies to prevent or effectively treat injury to the SDFT indicates the importance of understanding how it differs from tendons which are not injury-prone.

HYPOTHESIS

That the structural and material properties and matrix composition of the SDFT and CDET differ, reflecting their specific functional requirements in vivo.

METHODS

Forelimb tendons were harvested from 26 mature horses and loaded to failure prior to matrix composition analysis of specimens.

RESULTS

The SDFT had a significantly higher cross-sectional area, structural stiffness, failure load and failure strain and a lower elastic modulus than the CDET (P < 0.0001).

CONCLUSIONS

The SDFT has conflicting requirements for strength and elasticity; although as a whole it is a stiffer structure than the CDET, differences in the matrix molecular composition including water and total sulphated glycosaminoglycan contents allow it to remain more elastic as a material.

POTENTIAL RELEVANCE

Further information on how the two tendons attain these different properties may be of use in the development of prevention and treatment strategies for SDFT rupture.

Expression, purification, and efficacy of the type A botulinum neurotoxin catalytic domain fused to two translocation domain variants

Clostridial neurotoxins are potent inhibitors of synaptic function, with the zinc-dependent proteolytic light chain (LC) portion of the toxin cleaving one of three neural SNARE proteins. In nature, the LC is expressed as a part of a much larger toxin and hemagglutinin complex, protecting it from environmental degradation and preserving its catalytic activity. We developed forms of the LC of type A botulinum neurotoxin (BoNT-A) with parts of the larger toxin gene, for use as reagents in high-throughput assays to screen for potential LC antagonists, to further elucidate the toxin's mechanism of action, and to study immunological responses to the toxin. Three BoNT-A constructs were engineered and expressed: the LC, LC with translocation region (LC+H(n)), and the LC with the belt portion of the translocation region (LC+Belt). Purification was optimized to a two-step process, with relatively high yields of all three constructs obtained. Activity assays showed all three constructs to be active, with the LC being the most active. Immunogenic protection against native BoNT-A toxin challenge was observed for all three constructs, with the best protection observed with the LC+H(n) and LC+Belt proteins.

Infant doses from the transfer of radionuclides in mothers' milk

Assessments of potential internal exposures of the child following radionuclide intakes by the mother require consideration of transfers during lactation as well as during pregnancy. Current ICRP work on internal dosimetry includes the estimation of radiation doses to newborn infants from radionuclides ingested in mothers' milk. Infant doses will be calculated for maternal intakes by ingestion or inhalation of the radionuclides, radioisotopes of 31 elements, for which fetal dose coefficients have been published. In this paper, modelling approaches are examined, concentrating on models developed for iodine, caesium, polonium, alkaline earth elements and the actinides. Comparisons of model predictions show maximum overall transfer to milk following maternal ingestion during lactation of about 30% of ingested activity for 131I, 20% for 45Ca and 137Cs, 10% for 90Sr, 1% for 210Po and low values of less than 0.01% for 239Pu and 241Am. The corresponding infant doses from milk consumption are estimated in preliminary calculations to be about two to three times the adult dose for 45Ca and 131I, 70-80% of the adult dose for 90Sr, about 40% for 137Cs, 20% for 210Po, and <0.1% for 239Pu and 241Am. Infant doses from radionuclides in breast milk are compared with doses to the offspring resulting from in utero exposures during pregnancy.

Dose coefficients for the embryo and fetus following intakes of radionuclides by the mother

The International Commission on Radiological Protection has recently issued Publication 88, giving dose coefficients for the embryo, fetus and newborn child from intakes of selected radionuclides of 31 elements by the mother, either before or during pregnancy. The biokinetic models used for calculating these doses were based upon the available human data and the results of animal experiments. This paper summarises the approach used for the development of biokinetic and dosimetric models. It also compares the estimates of dose received by the offspring with those received by the reference adult. The main findings are that, in general, doses to the offspring are similar to or lower than those to the reference adult. For a few radionuclides, however, the dose to the offspring can exceed that to the adult. The reasons for these variations in comparative doses are examined.

Biokinetics and assessment of intake of thorium dioxide

The aim of this work was to investigate the biokinetics of thorium dioxide in animals for the purpose of assessing intakes of the compound by workers and the resulting doses. The results imply that measurements of the decay products in the chest or extrapolations from urine analysis data are unlikely to be of value for doses below 20 mSv. Even higher doses should be interpreted with caution as a consequence of uncertainties in particle size distribution and variations in dietary excretion.

Transfer of alkaline earth elements in mothers' milk and doses from 45Ca, 90Sr and 226Ra

An international programme of work is currently under way to develop methods for calculating doses to infants from ingestion of radionuclides present in mothers' milk. This paper considers the special case of the alkaline earth elements. Models have been developed for 45Ca, 90Sr and 226Ra and the sensitivity of results to various changes in parameter values is discussed. A complication when calculating doses from intakes of radium is that the International Commission on Radiological Protection has previously recommended that doses from decay products of radium should be calculated using element-specific biokinetic models (so-called independent biokinetics). An extension of this method to the models for breastfeeding is proposed. Preliminary estimates of the doses received by the infant for a number of maternal intake scenarios show that doses to the infant can exceed the corresponding adult dose, such as for 45Ca (ratio = 3.1) while, in other cases such as 90Sr, the infant dose can be a significant fraction of the adult dose.

Doses to organs and tissues from radon and its decay products

This paper discusses the doses from radon and from its short-lived decay products to a number of organs and tissues and to the foetus. The aim is to put all these doses into context rather than concentrating only on the largest contributions. There is also a brief discussion of the evidence from epidemiology on the risks of exposure to radon and its decay products. As is well known, under normal circumstances the greatest hazard is to the respiratory tract from inhalation of radon decay products. Radon decay products may also give substantial doses to skin. Under some circumstances it seems likely that ingested radon could give significant doses to the stomach. Other risks appear to be smaller; the results given here allow them to be compared.

Expression of mRNA transcripts for ATP-sensitive potassium channels in human myometrium

The molecular mechanisms regulating human uterine quiescence and parturition are poorly understood. Potassium channels are central to regulation of cell membrane potential and contractility of smooth muscle. The aim of this study was to examine the expression of ATP-sensitive potassium channel (K(ATP) channel) subunits in human myometrium, and to investigate for possible differential expression of these subunits in myometrium obtained from three different functional states: (i) non-pregnant (NP); (ii) late pregnant not in labour (PNL); and (iii) late pregnant in labour (PL). RT-PCR detected the presence of mRNA for four subunits of K(ATP) channels (Kir6.1, Kir6.2, SUR1 and SUR2B) in the three tissue types. Quantitative analysis of these subunits was achieved with real-time RT-PCR using Lightcycler(TM) technology. This analysis showed that there were significantly higher levels of Kir6.1 and SUR2B transcripts in NP myometrium compared with those measured in myometrium obtained during pregnancy (P < 0.001). Lower levels of Kir6.2 and SUR1 mRNA expression were found, although higher transcript levels in NP myometrium (P < 0.05) were still observed. Our results indicate that the major K(ATP) channel expressed in human myometrium is composed of Kir6.1 and SUR2B, and that down-regulation of this channel may facilitate myometrial function during late pregnancy.

Do regional variations in flexor tendons predispose to site-specific injuries?

Partial rupture occurs most often to the superficial digital flexor tendon (SDFT) of the forelimb at the mid-metacarpal level. In this study, we tested the hypothesis that the mid-metacarpal region of the SDFT has the smallest cross sectional area (CSA) and a similar collagen content to other regions and, therefore, represents a weak point in the tendon. The SDFT was collected from the forelimbs of 9 horses. Each tendon was marked at 7 different levels from the origin of the accessory ligament to the phalangeal region. The CSA, water content and collagen content was measured at each level. The mid-metacarpal level had a significantly smaller CSA than the most proximal and distal levels measured and a significantly higher dry matter content than proximal levels. However, the total amount of collagen present in the mid-metacarpal section was not significantly less than other regions except for the most distal sections. The results of this study suggest that the mid-metacarpal region of the SDFT, although smaller in CSA, is not significantly weaker than the proximal end and manica flexoria region of the tendon. Therefore, other factors such as hypoxia and/or hyperthermia may be responsible for site-specific tendon lesions in the SDFT.

Potent neutralization of botulinum neurotoxin by recombinant oligoclonal antibody

The botulinum neurotoxins (BoNTs) cause the paralytic human disease botulism and are one of the highest-risk threat agents for bioterrorism. To generate a pharmaceutical to prevent or treat botulism, monoclonal antibodies (mAbs) were generated by phage display and evaluated for neutralization of BoNT serotype A (BoNT/A) in vivo. Although no single mAb significantly neutralized toxin, a combination of three mAbs (oligoclonal Ab) neutralized 450,000 50% lethal doses of BoNT/A, a potency 90 times greater than human hyperimmune globulin. The potency of oligoclonal Ab was primarily due to a large increase in functional Ab binding affinity. The results indicate that the potency of the polyclonal humoral immune response can be deconvoluted to a few mAbs binding nonoverlapping epitopes, providing a route to drugs for preventing and treating botulism and diseases caused by other pathogens and biologic threat agents.

Dose coefficients for the embryo and foetus following intakes of radionuclides by the mother

Committee 2 of the International Commission on Radiological Protection (ICRP) has the responsibility for calculating radiation doses from intakes of radionuclides for all age groups in the population. Publication 88 of the ICRP, which has recently been published, describes the development of models used for calculating radiation doses to the embryo and foetus following intakes of radionuclides by the mother. It also gives radiation doses to the offspring for intakes of radionuclides by the mother either before or during pregnancy. The approaches used in the development of the biokinetic and dosimetric models are summarised here together with a comparison of the doses to the offspring with those to the reference adult.

Synergism of ergonomics, safety, and quality--a behavioral cybernetic analysis

This report extends a control systems or cybernetic model of behavior to the behavior of groups of many individuals--organizations and institutions--operating together with technology as complex sociotechnical (ST) systems. The premise is that the level of quality in performance of a complex ST system is predicated upon the degree to which its organizational design incorporates elements of a closed-loop behavioral control system: control goals and objectives, sensory receptors, sensory feedback, learning and memory, effectors, and sensory feedback control. From a control systems perspective, ergonomics is essential to effective organizational self-regulation. If working conditions are poorly designed, work performance and safety and quality outcomes cannot be closely controlled. Conversely, as shown by field evidence, good design promotes synergism between ergonomics, safety, and quality as a closed-loop consequence of effective employee and organizational self-control of system performance, safety, and quality.

Expression and modulation of Rho kinase in human pregnant myometrium

There is little information outlining the role of Rho kinase, RhoA, and calcium sensitization in regulation of human uterine contractility during pregnancy. The aims of this study were to investigate the expression of RhoA, and the Rho kinases ROCK I and ROCK II in human pregnant myometrium, to evaluate the effects of Rho kinase inhibition on pregnant human myometrial contractility in vitro, and to compare these effects with those of the calcium channel blocker nifedipine. RT-PCR using primers for RhoA, ROCK I and ROCK II was performed on mRNA isolated from human pregnant myometrium. Isometric recording was performed in isolated myometrial strips obtained at Caesarean section. The effects of the Rho kinase inhibitor Y-27632 (1 nmol/l to 10 mmol/l), and nifedipine (1 nmol/l to 10 mmol/l), on oxytocin (0.5 nmol/l) induced contractions were measured and compared. Expression of RhoA, ROCK I and ROCK II mRNA was identified in human pregnant myometrium (n = 3). Y-27632 exerted a potent relaxant effect on myometrial contractility with a pD(2) value (+/- SEM) of 7.63 +/- 0.38 (n = 6). The maximum net relaxant effect (+/- SEM) was 72.3 +/- 6.1% (n = 6). Corresponding values for nifedipine were 7.24 +/- 0.48 (n = 6; P = 0.469) and 93.40 +/- 3.1% (n = 6; P = 0.028). Rho A/Rho kinase-mediated calcium sensitization may play role in the physiology of human parturition, and pharmacological inhibition of this pathway may therefore provide a novel approach to tocolysis for pre-term labour.

Mechanisms of carcinogenesis inhibition by isothiocyanates

Epidemiological studies have suggested that frequent consumption of cruciferous vegetables is associated with a decreased risk in various types of cancer. Cruciferous vegetables are commonly consumed foods that contain organosulfur compounds known as isothiocyanates. These compounds are potent inhibitors of chemically induced carcinogenesis in animals. Extensive work has been conducted to elucidate the mechanisms involved in the inhibition of carcinogenesis by isothiocyanates. These mechanisms include blocking the metabolic activation of the carcinogens by way of altering the enzymes involved in the process, induction of detoxification enzymes and induction of apoptosis. Since their mode of action is selective, the enzyme composition of the tissue and the inhibition or induction of the enzymes by the isothiocyanates will influence their chemopreventive activities. Isothiocyanates may potentially be beneficial in protecting against human carcinogenesis.

Ethics of rural health care

One quarter of the US population live in areas designated as rural. Delivery of rural health care can be difficult with unique challenges including limited access to specialists such as oncologists. The Rural Cancer Outreach Program is an alliance between an academic medical center and five rural hospitals. Due to the presence of this program, the appropriate use of narcotics for chronic pain has increased, the number of breast conserving surgeries has more than doubled and accrual to clinical trials has gone from zero to nine over the survey period. An increase in adjuvant chemotherapy has been noted. The rural hospitals and the academic center have seen a positive financial impact. The most prominent ethical issues focus on justice, especially access to health care, privacy, confidentiality, medical competency, and the blurring of personal and profession boundaries in small communities. As medical care has become more complex with an increasing number of ethical issues intertwined, the rural hospitals have begun to develop mechanisms to provide help in difficult situations. The academic center has provided expertise and continued education for staff, both individually and within groups, regarding ethical dilemmas.

Effects of purified green and black tea polyphenols on cyclooxygenase- and lipoxygenase-dependent metabolism of arachidonic acid in human colon mucosa and colon tumor tissues

The effects of green and black tea polyphenols on cyclooxygenase (COX)- and lipoxygenase (LOX)-dependent arachidonic acid metabolism in normal human colon mucosa and colon cancers were investigated. At a concentration of 30 microg/mL, (-)-epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC), and (-)-epicatechin-3-gallate (ECG) from green tea and theaflavins from black tea inhibited LOX-dependent activity by 30-75%. The formation of 5-, 12-, and 15-LOX metabolites was inhibited to a similar extent. Tea polyphenols also inhibited COX-dependent arachidonic acid metabolism in microsomes from normal colon mucosa, with ECG showing the strongest inhibition. The formation of thromboxane (TBX) and 12-hydroxyheptadecatrienoic acid (HHT) was decreased to a greater extent than other metabolites. The inhibitory effects of tea polyphenols on COX activity, however, were less pronounced in tumor microsomes than in normal colon mucosal microsomes. Theaflavins strongly inhibited the formation of TBX and HHT, but increased the production of prostaglandin E(2) (PGE(2)) in tumor microsomes. The enhancing effect of theaflavins on PGE(2) production was related to the COX-2 level in the microsomes. Although theaflavin inhibited ovine COX-2, its activity in the formation of PGE(2) was stimulated by theaflavin when ovine COX-2 was mixed with microsomes, suggesting that theaflavin affects the interaction of COX-2 with other microsomal factors (e.g. PGE synthase). The present results indicate that tea polyphenols can affect arachidonic acid metabolism in human colon mucosa and colon tumors, and this action may alter the risk for colon cancer in humans.