Polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) selected chlorinated pesticides, polycyclic aromatic hydrocarbons (PAH) and some volatile organic compounds (VOC) were analysed in the exhaust fumes of candles made from different waxes and finishing materials. To guarantee defined burning conditions a chamber was developed for the sampling of the exhaust fumes. Using a simple exposure model, the inhalative uptake of PCDD/PCDF by an adult person was calculated for different scenarios. It was shown that additional uptake of PCDD/PCDF caused by candle emissions does not contribute significantly to the total daily intake of these compounds. Emissions of PCDD/PCDF, benzo(a)pyrene and the VOC were then compared to limit value for working places. Even when many candles would be burnt at the same time in a small room, concentrations of the compounds investigated stay below 1% of the tolerable limit values.

Administration, Inhalation↗

PubMedDate not supplied

Lack of evidence for intergenerational reproductive effects due to prenatal and postnatal undernutrition in the female CD-1 mouse.

The impacts of adverse environments during the prenatal and/or early postnatal periods may be manifested as functional deficits that occur later in life. Epidemiological studies have shown an association of sub-optimal pregnancy outcomes in one generation with similar events in the following one, a phenomenon termed the "intergenerational effect". Data indicate that the incidence of adverse pregnancy outcomes and/or low birth weight infants is more closely correlated with the mother's perinatal environment than with that during her pregnancy. However, epidemiological studies are inherently limited given the variability of lifestyles, ethnicity, nutritional status, and exposures to environmental factors. An appropriate animal model would permit control of parameters that may be impossible to evaluate in human populations. The current studies investigated the mouse as a possible animal model. Pregnant CD-1 mice were placed on an ad libitum or food-restricted diet (50% normal) throughout gestation to generate control (CON) and intrauterine growth retarded (IUGR) litters. At birth (postnatal day (PD) 1) pups (F1) were cross-fostered to control dams in litters of either 8 (CON) or 16 (postnatal food restriction (FR)). The experimental groups thus generated represented adequate nutrition (CON-CON) and undernutrition during the prenatal (IUGR-CON), or postnatal periods (CON-FR), or both (IUGR-FR). Pups of dams on a restricted diet during gestation had significant IUGR (P<0.001) as compared to controls (birth weights of 1.32 g versus 1.63 g). At weaning, the average weight of the pups was dependent on postnatal litter size and the difference in birth weights between IUGR and CON animals was not a significant factor. CON-CON pup weight was 24.1g and IUGR-CON was 22.2 g as compared to the CON-FR (17.0 g) and IUGR-FR (17.3 g) groups. The difference in weaning pup weights between the FR and CON groups was significant (P<0.01). The F1 FR females did not reach CON female weights at any time point through 11 months after weaning. At PD60, a single breeding period for all groups of females with CON males began and continued for 75 days with 17 opportunities for breeding. Animals that became pregnant during this time were removed and allowed to litter. No significant differences were noted in average F2 litter size or average pup weight at birth: (CON-CON 12.2/1.62 g; IUGR-CON 11.9/1.6 2 g; CON-FR 10.9/1.70 g; IUGR-FR 11.3/1.61 g). We conclude that body weight at birth in the CD-1 mouse is not correlated with growth through the period of weaning (PD28). We did not find any evidence for an intergenerational reproductive effect after developmental undernutrition.

Animal Nutritional Physiological Phenomena↗

PubMedDate not supplied

Development of cholinergic neurons in rat brain regions: dose-dependent effects of propylthiouracil-induced hypothyroidism.

The effects of hypothyroidism on development of cholinergic system in brain regions (prefrontal cortex and hippocampus) were evaluated by measuring choline acetyltransferase (ChAT) activity and hemicholinium-3 binding to the high-affinity choline transporter. Various degrees of thyroid deficiency were produced by perinatal exposure to propylthiouracil (PTU) in drinking water ranging from 5 ppm (mg/l) to 25 ppm beginning at gestational day 18 until postnatal day 21. ChAT, a marker for cholinergic nerve terminals, was reduced by PTU in a dose-dependent manner. Concomitant with the enzyme deficits, hemicholinium-3 binding was elevated, suggesting an increase in neuronal impulse activity. Although similar changes were seen in both brain regions examined, the magnitude and duration of these changes were more definitive in the prefrontal cortex. Nonetheless, these neurochemical alterations appeared to be recoverable when the rats returned to a euthyroid state, and no further changes were observed as the animals reached adulthood. In comparison, data reported in a succeeding article indicate that deficits in cognitive function were first seen in weanling hypothyroid rats, but that the behavioral impairments lasted well into adulthood when thyroid status and cholinergic parameters in the brain appeared to have recovered to normal. These results suggest that alterations of cholinergic system caused by perinatal hypothyroidism are associated with neurobehavioral deficits at weaning, and these developmental deviations may cause permanent impairment of cognitive function despite recovery from the hormonal imbalance at adult ages.

Animals↗

PubMedDate not supplied

Comparison study of QuickCast versus a traditional thermoplastic in the fabrication of a resting hand splint.

Therapists are frequently presented with new splinting material promising better and faster results. Managed care and cost containment make it important to evaluate the splinting materials used in the fabrication process. A new precut splint, QuickCast, is made from a fiberglass material that becomes pliable from the heat of a standard household hair dryer. Graduate occupational therapy students participated in timed trials fabricating resting hand splints with QuickCast and Ezeform brands of thermoplastic. Second-year occupational therapy students chosen as splint makers answered a questionnaire measuring fit, edges, strap application, aesthetics, safety, and ease of positioning. First-year students who had no neurologic or orthopedic involvement in the upper extremities participated as clients. They answered a questionnaire on comfort, weight, and aesthetics of the splint and the safety and comfort of the splinting process. Analysis of timed trials revealed no significant difference in the time required to fabricate the QuickCast precut thermoplastic and the sheet thermoplastic splints. From the questionnaire, the thermoplastic splint was rated safer than the QuickCast material by splint makers. Further studies are suggested for comparing time and cost effectiveness between commercially available splinting materials.

Equipment Design↗

PubMedDate not supplied

Non-invasive image acquisition and advanced processing in optical bioimaging.

Light is a most versatile tool for investigating biological systems and phenomena; the range, non-destructiveness, spatial discrimination and speed of optical imaging are all important for investigating structure and function at the cellular, tissue or even whole organism level. In live biological imaging, where the technological requirements are heightened, other features of light, such as coherence and wavelength, are used to generate the additional contrast and resolution needed. We report here recent improvements in our ability to image biological specimens optically, focusing on (a) spectral resolution and the related image processing issues, and (b) tomographic three-dimensional fluorescence imaging in vivo.

Fluorescence↗

PubMedDate not supplied

Cardiac pacing following surgery for acquired heart disease.

BACKGROUND: This study is comprised of 3493 consecutive patients who underwent open heart surgery at our institution. Data on all patients were collected prospectively. METHODS: In 45 patients (Group P) (1.3%), a permanent pacemaker (PP) was inserted postoperatively. For the purpose of the study, these patients were compared to 3448 patients (Group NP) who did not require insertion of a PP after surgery. Mean follow-up was 33 months (range 1.5 to 66). RESULTS: We found Group P patients were older (64.8 +/- 11.0 vs 61.0 +/- 11.0 years, p < 0.05), had a higher proportion of elderly (> 70 years) 36% vs 19%, p = 0.01), and of female patients (48.8% vs 22.7%, p < 0.001) compared to Group NP. Group P also had a higher incidence of preoperative rhythm abnormalities (26.6% vs 5.7%, p < 0.0001), redo surgery (13.3% vs 4.6%, p = 0.02), aortic valve surgery (48.8% vs 10.8%, p < 0.001), and tricuspid valve surgery (repair 3, replacement 1) (8.8% vs 0.5%, p < 0.001), in addition to a higher proportion of patients in whom cold (vs warm) blood cardioplegia was used (68.8% vs 52.3%, p = 0.03). Indication for postoperative PP was sick sinus syndrome (SSS) in nine patients; atrial fibrillation in eight patients; atrioventricular block (AVB) in 27 patients; and combined AVB/SSS in 1 patient. There were no operative deaths in Group P. Necessity for PP after heart surgery had a significant impact on resource utilization resulting in prolonged ventilation (3.1 +/- 7.5 vs 1.4 +/- 3.3 days, p < 0.01), intensive care unit (5.1 +/- 10.2 vs 2.5 +/- 4.0 days, p < 0.01), and postoperative hospital stay (18.0 +/- 13.4 vs 8.1 +/- 9.4 days, p < 0.01). CONCLUSIONS: By multivariate logistic regression (odds ratio and p value in parentheses), aortic valve surgery (8.23, p = 0.001), the absence of preoperative sinus rhythm (5.60, p = 0.001), postoperative myocardial infarction (3.46, p = 0.024), and female gender (2.52, p = 0.003), were found to be independent predictors for PP requirement post surgery.

Aged↗

PubMedDate not supplied

Neonatal hyperthyroidism causes premature development of baroreceptor-mediated cardiac sympathetic reflexes.

Baroreceptor-mediated reflex control of cardiac sympathetic activity does not appear fully until the third week of postnatal age in the rat, possibly because central processing of baroreceptor sensory input is deficient in the neonate. Hyperthyroidism, which accelerates synaptogenesis in the peripheral sympathetic and central nervous systems, was produced by administering 3,3',5-triiodothyronine (T3) daily, and effects on development of baroreceptor-mediated sympathetic reflexes were evaluated. To test baroreceptor-mediated reflexes, control and T3-treated rats of different ages were given hydralazine acutely to produce a decrease in blood pressure, which in adult rats results in a large, sympathetically-mediated stimulation of cardiac ornithine decarboxylase (ODC) activity. In control neonates, cardiac ODC responses to hydralazine were absent until the 3rd week of age, but the T3-treated animals showed increases as early as 8 days of age. Furthermore, increased turnover of norepinephrine in cardiac sympathetic nerves in response to the hydralazine-induced hypotension was 2- to 3-fold higher in the 8-day-old T3-treated animals than in controls. These data indicate that the early appearance of the ODC response to hypotension in hyperthyroid rats results, at least in part, from precocious development of the ability of baroreceptor input to influence efferent sympathetic function.

Adrenergic Fibers↗

PubMedDate not supplied

Effects of age, feeding regimen, and glucocorticoids on catecholamine and cortisol excretion in preterm infants.

BACKGROUND: The sympathoadrenal system is important in maintaining normal physiologic functioning in infants and increased output also can reflect stress. We sought to determine the effects of age, feeding regimen, and glucocorticoids on catecholamine and cortisol excretion in preterm infants and to assess whether a particular strategy of feeding enhanced sympathoadrenal development or was stressful. METHODS: Preterm infants (26-30 wk gestation; n = 171) were assigned randomly to begin trophic feedings from day 4 through 14 (trophic group) or to start feedings at day 15 (standard group) with feedings administered either by bolus every 3 hours (bolus) or continuously over 24 hours (continuous). At 10, 28, 40, 50, and 60 days of age, urine was collected continuously for 6 hours for measurement of catecholamines (norepinephrine, epinephrine, dopamine), cortisol, and creatinine. Data were available for 98 infants. RESULTS: Norepinephrine excretion increased with postnatal age. The increase with age was significantly greater in the trophic group compared with that in the standard group. Epinephrine excretion did not change with age, and there were no differences between trophic and standard groups. Dopamine excretion increased with age but was similar between trophic and standard groups (borderline significantly greater in the trophic group). Cortisol excretion increased with age and also was similar between trophic and standard groups. There was no effect on catecholamine or cortisol excretion of bolus vs continuous feedings, antenatal or postnatal corticosteroids, gestational age at birth, age at which full feedings were attained, or use of human milk compared with preterm formula. CONCLUSIONS: The greatest determinant of catecholamine and cortisol excretion is postnatal age. Feeding method, type of feeding, and glucocorticoid administration in the amounts customarily used have little significant effect on catecholamine or cortisol excretion. The apparent link between early feeding and norepinephrine (and possibly dopamine) excretion warrants further investigation.

Age Factors↗