Effects of a five-hour exposure of arm and leg to a slightly cool thermal environment in the afternoon on the body temperature rhythm

The purpose of this study was to determine whether the different thermal conditions of the arm and leg due to wearing different types of clothing during the afternoon could modulate the circadian rhythm of body temperature and subjective sleep quality. Six healthy female volunteers were studied twice with two types of clothing, leaving the arm and leg covered or uncovered. The environmental chamber was controlled at 24 ± 0.5°C and 50 ± 5% RH during wakefulness and 28 ± 0.5°C and 50 ± 5% RH during night sleep. One type of clothing consisted of long-sleeved shirts and full-length trousers (Type L, 989 g, 0.991 clo); the other type was of half-sleeved shirts and knee-length trousers (Type H, 750 g, 0.747 clo). One testing session lasted for 16 h from 14:00 to 06:00 h the next morning. Subjects wore Type L or Type H clothing during the afternoon exposure (14:00 - 19:00), and Type L clothing during the evening (19:00 - 22:30 h) and the night sleep (22:30 - 06:00 h). Results were as follows. (1) When wearing Type H rather than Type L clothing, skin temperatures of the arm and leg were significantly lower during the time of exposure, and increased more after the evening. (2) Rectal temperature was not significantly different between the two types of clothing except during the early part of the exposure period, but it decreased during the evening by a significantly greater amount when wearing Type H clothing. (3) Subjective sleep quality was not significantly different between the two clothing types. These results suggest that afternoon exposure of the arm and leg to a slightly cool environment does not have a strong after-effect on the body temperature and subjective sleep quality.     

Circadian Rhythms in the Efficacy of Intravenous Alteplase in Patients With Acute Ischemic Stroke and Middle Cerebral Artery Occlusion

Circadian rhythm interactions of hemostatic factors can modify tissue plasminogen activator (tPA) effects. We assess the relationship of the time frame of intravenous tPA administration with the outcome of patients with acute ischemic stroke (AIS). We studied 135 consecutive patients with AIS and transcranial duplex documented middle cerebral artery (MCA) occlusion treated with intravenous tPA. Complete recanalization was defined as total improvement on thrombolysis in brain ischemia (TIBI) grades 2?h after tPA infusion. Clinical response was evaluated by the modified Rankin scale at 90 days. We determined plasminogen activator inhibitor-1 (PAI-1) levels in 33 patients with available plasma samples before treatment. Our results are follows: 92 (68.1%) patients were treated in the diurnal (9:00–21:00) and 43 (31.8%) in the nocturnal period (21:00–9:00). Complete recanalization was recorded in 52/135 (38.5%) patients. Both the rate of complete recanalization (45.6% vs. 23.2%; p?=?.01) and good clinical outcome (64.1% vs. 44.2%; p?=?.02) were significantly higher in the group of diurnal tPA administration compared with those treated in the nocturnal period. The adjusted odds ratio (OR) of diurnal tPA treatment for complete MCA recanalization was 2.37 (95% confidence interval [CI], 1.02–5.52; p?=?.045). Diurnal tPA infusion significantly improved the overall distribution of scores on the modified Rankin scale, as compared with nocturnal treatment (OR, 2.07; 95% CI, 1.16–4.64 by ordinal regression analysis). Low PAI-1 levels were associated with complete recanalization but did not significantly differ between the two time frames. In conclusion, diurnal administration of tPA is associated with complete MCA recanalization and better functional outcome at 90 days in patients with AIS. (Author correspondence: mgomis.germanstrias@gencat.cat, meritxellgomis@gmail.com)     

Considerations in the grouping of plant and fungal taxa for an epidemiologic study

Although exposure to airborne pollen grains and fungal spores has been implicated as a causative factor for acute exacerbation of asthma, the few epidemiologic studies that have attempted to evaluate the relationship between these bioaerosols and asthma have used only total counts (ignoring the relative importance of different taxa) or a few predominant pollen or spore types (ignoring less abundant but potentially relevant groups). This paper reports the development of hypothesis‐driven exposure metrics (based on known aeroallergen associations with allergic asthma and other hypersensitivity diseases, pollen allergen cross‐reactivity, and the presence of local sources in the city of Fresno, California, USA) for a 3.5 year epidemiologic study of childhood asthma. Outdoor regional and neighborhood concentrations of pollen and spores were measured using Hirst‐type, 7‐day samplers. Indoor and outdoor residential concentrations were measured at 84 selected homes with similar 24‐hour slit impactors. All pollen and spore concentrations were recorded in 2‐hour intervals to assist in understanding diurnal fluctuations in aeroallergen concentrations, identify exposures during the time periods that children are outdoors, and study interaction between aeroallergens and other air contaminants, which were the primary focus of the study. The 124 pollen taxa that were observed were reduced to 15 categories and the 66 fungal and algal taxa were reduced to five categories that will be used in microenvironmental models to generate individual daily exposure estimates for each of the 315 children. These new exposure metrics will allow examination of health effects for taxa traditionally associated with allergy and those with locally elevated concentrations in combination with exposures to other indoor and outdoor air contaminants.     

Methodology to Capture Children's Non-Dietary Ingestion Exposure Activities During Meal Events

During meal events, a child's food can be contaminated through contacts with objects and surfaces, and/or unwashed hands that have chemical residues, increasing ingestion exposure of contaminants for the child. This is not surprising, given that very young children eat more with the hands than adults, are active, and play with toys and objects while eating. In addition, children's unwashed hands and toys are commonly inserted into their mouths during meal events, increasing exposure. By observing children during their meal events, information can be gathered on the frequency and duration of contacts between objects, foods, and hands, and the sequence of events before the hands, foods, or objects are inserted into the mouth. This article describes the process of refining a videotaping and video-translation methodology to capture micro-level activity time series (MLATS), in order to better quantify total exposure for young children as a result of their behavior during meal events and cross-contamination of foods and hands. These MLATS can be seen as detailed activity patterns that provide useful data, along with transfer coefficients and environmental concentration to estimate exposures.     

In silico evaluation of pharmacokinetics and acute toxicity of withanolides in Ashawagandha

Ashwagandha is a medicinal plant used in traditional Asian medicines as an adaptogen to promote both physical and mental health. Withanolides are the major bioactive phytochemicals in Ashwagandha; they are a group of naturally occurring C₂₈-steroidal lactones with an ergostane-based skeleton. Despite the broad use of Ashwagandha, data on the pharmacokinetic and toxicological properties of withanolides remain scarce. Here, 75 withanolides in Ashwagandha were identified in journal publications, databases, and monographs. In silico quantitative structure-activity relationship (QSAR) models were used to evaluate the physicochemical and pharmacokinetic properties as well as the acute toxicity of withanolides. Withanolides had high molecular weight and pKa, low aqueous solubility, and high lipophilicity. QSAR models also predicted high effective human jejunal permeability and plasma protein binding, tissue partitioning, extensive metabolism, hepatic uptake, and renal excretion for certain withanolides. In addition, two thirds of the withanolides evaluated had predicted median lethal dose (LD₅₀) under 100 mg/kg after oral administration in rats. These in silico results could be used to guide further testing and confirmed by in vitro and in vivo studies.     

A need to provide explanations for observed biological effects of radiofrequency exposure

Abstract

Although there is scientific consensus that radiofrequency (RF) exposure at high intensity can cause thermal effects, including well-established adverse health effects, there is still considerable controversy on whether low-intensity RF exposure can cause biological effects, especially adverse health effects. The objective of this paper is to describe several reported “non-thermal” effects that were later shown to be due to a weak thermal effect or an experimental artifact by properly conducted and thorough follow-on scientific research. First, the multiple factors that can cause different RF energy absorption in biological tissues are reviewed and second, several examples of experimental artifacts in published papers are described to demonstrate the importance of paying attention to dosimetry and temperature control. For example, isolated nerve response studies show that when temperature of the RF-exposed tissues is controlled, effects disappeared. During RF exposure, conductive electrodes routinely used in physiological studies have been shown to cause field intensification at the tips or contacts of the electrodes with biological tissue; thus, the RF exposure at the site of measurement could be much higher than the incident field. In some in vitro studies, a lack of temperature uniformity in RF-exposed cell cultures and rate of heating explain changes originally reported to be due to low-level RF exposure. In other studies, detailed dosimetry studies have identified artifacts that explain the reasons why so-called “non-thermal” effects were mistakenly reported. Researchers should look for explanations for their own findings, and not expect others to figure out what was the reason for their observed effects.     

Feeding responses of specialist herbivores to plant extracts and pure allelochemicals: effects of prolonged exposure

We investigated the possibility of decreased feeding deterrent response following prolonged exposure in three specialist herbivores, Plutella xylostella (larvae), Pseudaletia unipuncta (larvae), and Epilachna varivestis (adults) through leaf disc choice and no‐choice tests. Neonate larvae (<24 h old) of the three species were reared on their host plants sprayed with the antifeedants until tested. Our results demonstrated that Ps. unipuncta did not show a decrease in feeding deterrent response to extracts of Melia volkensii (choice and no‐choice tests) or oregano (Origanum vulgare) (choice test) following prolonged exposure. Plutella xylostella exhibited a decrease in feeding deterrent response to M. volkensii in a choice test only, but not to oregano. Although not significant, we did find a trend toward decreasing feeding deterrent response to M. volkensii by both species in no‐choice tests. However, both species exhibited a significant decrease in feeding deterrent response to pure allelochemicals (Ps. unipuncta to thymol, and P. xylostella to thymol and toosendanin) compared with the naïve groups, following prolonged exposure in leaf disc choice tests. Epilachna varivestis showed a significant decrease in feeding deterrent responses to both oregano and thymol in leaf disc choice tests. We conclude from our present and previous studies that not only are there interspecific differences between generalist and specialist species but also among specialist species.     

A free-air enrichment system for exposing tall forest vegetation to elevated atmospheric CO2

A free-air CO₂ enrichment (FACE) system was designed to permit the experimental exposure of tall vegetation such as stands of forest trees to elevated atmospheric CO₂ concentrations ([CO₂]_a) without enclosures that alter tree microenvironment. We describe a prototype FACE system currently in operation in forest plots in a maturing loblolly pine (Pinus taeda L.) stand in North Carolina, USA. The system uses feedback control technology to control [CO₂] in a 26 m diameter forest plot that is over 10 m tall, while monitoring the 3D plot volume to characterize the whole-stand CO₂ regime achieved during enrichment. In the second summer season of operation of the FACE system, atmospheric CO₂ enrichment was conducted in the forest during all daylight hours for 96.7% of the scheduled running time from 23 May to 14 October with a preset target [CO₂] of 550 μmol mol^–1, ≈ 200 μmol mol^–1 above ambient [CO₂]. The system provided spatial and temporal control of [CO₂] similar to that reported for open-top chambers over trees, but without enclosing the vegetation. The daily average daytime [CO₂] within the upper forest canopy at the centre of the FACE plot was 552 ± 9 μmol mol^–1 (mean ± SD). The FACE system maintained 1-minute average [CO₂] to within ± 110 μmol mol^–1 of the target [CO₂] for 92% of the operating time. Deviations of [CO₂] outside of this range were short-lived (most lasting < 60 s) and rare, with fewer than 4 excursion events of a minute or longer per day. Acceptable spatial control of [CO₂] by the system was achieved, with over 90% of the entire canopy volume within ± 10% of the target [CO₂] over the exposure season. CO₂ consumption by the FACE system was much higher than for open-top chambers on an absolute basis, but similar to that of open-top chambers and branch bag chambers on a per unit volume basis. CO₂ consumption by the FACE system was strongly related to windspeed, averaging 50 g CO₂ m^–3 h^–1 for the stand for an average windspeed of 1.5 m s^–1 during summer. The [CO₂] control results show that the free-air approach is a tractable way to study long-term and short-term alterations in trace gases, even within entire tall forest ecosystems. The FACE approach permits the study of a wide range of forest stand and ecosystem processes under manipulated [CO₂]_a that were previously impossible or intractable to study in true forest ecosystems.     

Ochratoxin A blood concentration in healthy subjects and bladder cancer cases from Pakistan

Astract  The mycotoxin ochratoxin A (OTA) is a public health issue in many countries. Data on OTA concentrations in foods and in blood are available for several European countries including the Balkan area, as well as for Canada and Japan. Yet, for developing countries such data are scarce. In this study we determined OTA blood levels as biomarker of exposure in bladder cancer patients and in healthy controls from Pakistan. OTA in blood was analyzed after extraction by HPLC with fluorescence detection (limit of detection: <0.03 ng/mL) in 96 patients and in 31 controls. Over 92% of all blood samples (87 patients, 30 controls) contained quantifiable amounts of OTA: The mean OTA concentrations were 0.33 ng/mL (SD 0.42; range: 0.03 to 3.41 ng/mL) in bladder cancer patients, and 0.31 ng/mL (SD 0.29; range: 0.04 to 1.25 ng/mL) in healthy controls. These OTA concentrations are comparable to those reported for the general population in the European Union. Presented at the 27^th Mykotoxin-Workshop, Dortmund Germany, done 13–15, 2005. The IfADo is accredited as WHO Cellaporating Center for Occupational Health.