Comparative Evaluations of Alternative Blowing Agent Systems in Appliance Foams and Cabinets

The Manufacture of HCFC-141b (used as an insulation foam blowing agent) will be discontinued in the United States on December 31, 2002. In addition, the United States appliance industry must meet a U.S. Department of Energy (DOE) requirement for energy redaction of up to 30% (compared to 1993 standards) by July of 2001.

Feasibility testing of alternate blowing agent foams was previously reported by the AHAM Industry/Government CFC Replacement Consortium and indicated a 6-10% increase in energy with cylopentane blown foams. The evaluations of HFC-245fa and HFC-236ea blown foams in non-optimized systems also had higher k-factors than HCFC-141b blown foams.

The Dow Chemical Company and Maytag-Galesburg Refrigerator Products have conducted additional blowing agent evaluations on a newly designed top freezer cabinet. HFC-245fa, HFC-236ea and cyclopentane have been evaluated and compared to HCFC-141b in rigid appliance systems utilized today. Several new polyols, surfactants and catalysts were utilized in this formulation design experiment. The performance of each of the alternative blowing agents was evaluated in laboratory samples and in refrigerator/freezer cabinet foaming trials.

Does consumption of high-fructose corn syrup beverages cause obesity in children?

The consumption of high-fructose corn syrup (HFCS) beverages has increased since the 1970s. At the same time, childhood obesity is on the rise, causing children to be at risk of heart disease, diabetes and other diseases. Healthcare providers have attributed childhood obesity to the consumption of HFCS in the form of beverages. This article will look at the available research and determine if there is scientific evidence underlying the idea that sweetened soft drinks, especially those containing HFCS, could cause or contribute to childhood obesity. A thorough literature search was performed using the ISI Web of Sciences, PubMed and Scopus databases within the years 2006-2012. The search generated 19 results. The articles were screened, and six were deemed eligible: four systematic reviews and two meta-analyses. Two systematic reviews found that there is no relationship between consumption of HFCS beverages and obesity in children. The other two systematic reviews found possible links between HFCS and childhood obesity. The meta-analysis articles found that consumption of HFCS beverages can contribute to childhood obesity, and limitation of sweetened beverages may help decrease obesity in children. Available research studies demonstrate inconclusive scientific evidence definitively linking HFCS to obesity in children.

Selective lead compounds against kinetoplastid tubulin

Kinetoplastid parasites are responsible for the potentially fatal diseases leishmaniasis, African sleeping sickness and Chagas disease. The current treatments for these diseases are far from ideal and new compounds are needed as antiparasitic drug candidates. Tubulin is the accepted target for treatments against cancer and helminths, suggesting that kinetoplastid tubulin is also a suitable target for antiprotozoal compounds. Selective lead compounds against kinetoplastid tubulin have been identified that could represent a starting point for the development of new drug candidates against these parasites.

Screening and synthesis: high throughput technologies applied to parasitology

High throughput technologies continue to develop in response to the challenges set by the genome projects. This article discusses how the techniques of both high throughput screening (HTS) and synthesis can influence research in parasitology. Examples of the use of targeted and phenotype-based HTS using unbiased compound collections are provided. The important issue of identifying the protein target(s) of bioactive compounds is discussed from the synthetic chemist's perspective. This article concludes by reviewing recent examples of successful target identification studies in parasitology.

Targeting invasion and egress: from tools to drugs?

A recent resurgence in the use of compounds to study essential biological processes raises important questions concerning the link between fundamental research and drug development. This article discusses many of the issues involved, in the context of host cell invasion and egress by parasites of the Phylum Apicomplexa. In addition, an overview of the key steps in invasion and egress is provided with a particular emphasis on potential parasite protein drug targets.

Early lead exposure produces lasting changes in sustained attention, response initiation, and reactivity to errors

The present study tested the hypothesis that early lead (Pb) exposure causes lasting attentional dysfunction. Long-Evans dams were fed Pb-adulterated water during gestation and/or lactation; the offspring were tested as adults. The results of a visual discrimination task revealed no Pb effects on learning rate or information-processing speed. However, lasting effects of the early Pb exposure were seen in the subsequent vigilance tasks, particularly in the final task in which onset of the visual cue and cue duration varied randomly across trials. Exposure during both gestation and lactation impaired response initiation. In addition, animals exposed to Pb during lactation only or lactation+gestation committed significantly more omission errors than controls under two specific conditions: (1) trials in which a delay was imposed prior to cue presentation and (2) trials that followed an incorrect response. The pattern of treatment differences indicated that early Pb exposure produced lasting impairment of sustained attention and increased reactivity to errors. Both effects may contribute to the cognitive impairment, problematic classroom behaviors, and increased delinquency associated with early Pb exposure in children. These findings also demonstrate that the developmental timing of the exposure determines the pattern of effects. Thus, conclusions regarding whether or not a particular cognitive or affective function is impaired or spared by early Pb exposure must be limited to the specific timing and intensity of exposure.

Prenatal cocaine exposure impairs selective attention: evidence from serial reversal and extradimensional shift tasks

This study assessed the effects of prenatal cocaine exposure on cognitive functioning, using an intravenous (IV) rodent model that closely mimics the pharmacokinetics seen in humans after smoking or IV injection and that avoids maternal stress and undernutrition. Cocaine-exposed males were significantly impaired on a 3-choice, but not 2-choice, olfactory serial reversal learning task. Both male and female cocaine-exposed rats were significantly impaired on extradimensional shift tasks that required shifting from olfactory to spatial cues; however, they showed no impairment when required to shift from spatial to olfactory cues. In-depth analyses of discrete learning phases implicated deficient selective attention as the basis of impairment in both tasks. These data provide clear evidence that prenatal cocaine exposure produces long-lasting cognitive dysfunction, but they also underscore the specificity of the impairment.

Effects of chronic lead exposure on learning and reaction time in a visual discrimination task

Long-Evans rats exposed chronically to lead (Pb) acetate (0, 75, or 300 ppm) were tested as adults on an automated, three-choice visual discrimination task as part of a larger study designed to elucidate the cognitive effects of developmental Pb exposure. Median adult BPb levels for the groups were <5, 20, and 36 microgram/dl. The pattern of results suggested a linear effect, with increasing lead dose producing progressively slower learning and an increased incidence of "impaired" individuals. This latter measure proved to be slightly more sensitive than the former, suggesting individual differences in susceptibility to Pb neurotoxicity. Additional analyses revealed that the impairing effect of Pb was seen in both the chance and post-chance learning phases, indicating that the deficit was not limited to (but could include) attentional function. Reaction time on incorrect trials was reduced in the 300-ppm group, whereas no Pb effect was seen for correct trials. The present findings suggest that chronic developmental Pb exposure produces an associative deficit as well as a tendency to respond rapidly, but does not affect information-processing speed.

Independent and combined effects of prolonged inhaled nitric oxide and oxygen on lung inflammation in newborn piglets

Clinical use of nitric oxide (NO) is usually in conjunction with high oxygen concentrations, the effects of which may include lung neutrophil accumulation, apoptosis and upregulation of antioxidant enzyme activity. To define the effects of NO on neutrophils from young piglets and its relationship to lung neutrophil dynamics during hyperoxia we exposed thirty piglets to room air (RA), RA+NO (50 ppm NO), O2 (FiO2> or =0.96) or O2+NO for 5 days. Ten additional animals breathed RA+NO or O2+NO, then recovered in RA for 3 days before sacrifice. Neutrophil CD18 and intracellular oxidant production were measured by flow cytometry. Lung apoptosis were assessed by TUNEL assay. Lung myeloperoxidase, SOD and catalase were measured biochemically. When compared to RA group, there was significant reduction in neutrophil CD18 and intracellular oxidant production in the RA+NO group, but lung MPO was unchanged. The O2 and O2+NO groups did not differ in CD18 expression or in intracellular oxidant production, but had significant increase in lung myeloperoxidase compared to the RA group. Apoptosis increased significantly only in the O2+NO group. The O2 group showed significantly increased lung SOD and catalase activity compared to the RA group, whereas the RA+NO and O2+NO groups did not. We conclude that inhaled NO at 50 ppm decreases neutrophil CD18 expression as well as intracellular oxidant production. However, this effect does not impact lung neutrophil accumulation during concurrent hyperoxia. The combination of NO and O2 exposure produces an increase in lung apoptosis. Finally, NO may prevent upregulation of SOD and catalase activity during hyperoxia, potentially increasing injury.

Enduring effects of early lead exposure: evidence for a specific deficit in associative ability

Long-Evans dams were exposed to Pb acetate in the drinking water during both gestation and lactation, or lactation only. This report presents the results of an automated, olfactory, serial reversal task administered to the adult offspring. Although overall learning rate was not significantly affected by Pb exposure, analyses of specific phases of the learning process revealed that all three exposed groups required significantly more trials than controls to reach criterion from the point at which perseverative responding to the previously correct cue ended. These in-depth analyses revealed that the reversal learning impairment of the Pb-exposed animals was not due to a deficit in inhibiting responses to the previously correct cue, the mechanism commonly assumed to underlie impaired reversal learning. Instead, the analyses revealed that two other independent Pb effects were responsible for the prolonged postperseverative learning period: a response bias and an impaired ability to associate cues and/or actions with affective consequences. The contribution of these two factors varied as a function of the timing and intensity of the Pb exposure. It is hypothesized that the Pb-induced associative deficit may reflect lasting damage to the amygdala and/or nucleus accumbens, which comprise a system thought to modulate the process by which environmental cues acquire affective significance.

Indolent carcinoid tumor of the sigmoid colon

Carcinoid tumors of the colon are a rare cause of colonic malignant disease. A case of carcinoid tumor of the sigmoid colon is presented that illustrates the indolent course of this type of tumor. The case presented highlights the clinicopathologic features of carcinoid tumors of hindgut origin, including advanced local and widely metastatic disease at the time of diagnosis in the absence of symptoms of the carcinoid syndrome. The diagnosis and management of gastrointestinal carcinoid tumors are reviewed.

Plasma cholesterol and depressive symptoms in older men

In several clinical trials of interventions designed to lower plasma cholesterol, reductions in coronary heart disease mortality have been offset by an unexplained rise in suicides and other violent deaths. We have tried to find out whether depressive illness is related to low plasma cholesterol concentrations in men of 50 years and older. In 1985-87, Beck depression inventories were obtained from 1020 white men, aged 50-89 years, in the Rancho Bernardo, California, cohort. Disease history and behaviours were assessed by standard questionnaires. Plasma cholesterol and weight were measured at this time, as they had been in 1972-74. Among men aged 70 years and older, categorically defined depression was three times more common in the group with low plasma cholesterol (< 4.14 mmol/L) than in those with higher concentrations (5/31 [16%] vs 22/363 [6%]; p = 0.033). Depressive symptom scores correlated significantly and inversely with plasma cholesterol concentrations, even after adjustment for age, health status, number of chronic illnesses, number of medications, and exercise, as well as measured weight loss and change in plasma cholesterol in the previous 13 years. Our finding that low plasma cholesterol is associated with depressive symptoms in elderly men is compatible with observations that a very low total cholesterol may be related to suicide and violent death. Since cholesterol lowering in the general population is widely recommended, this observation warrants further investigation.

National and international health agencies. Profile of key players

The major players in international health and health policy have a tremendous potential to contribute to the wellbeing of humankind. Multilateral organizations, such as WHO, have universal areas of concern. The financial multilateral agencies play a key role in influencing development through the leverage of financial resources. Bilateral agencies of donor countries influence health policy direction by the magnitude of their financial resources. Private organizations, including universities, foundations, professional associations, nongovernmental organizations, and US industry, play an important role in identifying important policy issues through research, designing and developing appropriate technology, and acquiring the knowledge base necessary to form sound international health policy decisions.

Failure of BCAA supplementation to promote nitrogen retention in injured patients

The purpose of this study was to determine if supplementing total parenteral nutrition (TPN) with lipids or the branched chain amino acids (BCAA) leucine, isoleucine, and valine influences nitrogen balance in the injured patient. Four TPN study solutions were used, with each patient receiving two of the solutions for 4 days each. Group A received solutions consisting of 19% and 44% BCAA, with nonnitrogen calories supplied by 100% carbohydrate. Group B received a 7:3 carbohydrate-to-lipid ratio of nonnitrogen calories as a fuel source. Neither BCAA supplementation nor varying fuel substrates promoted a difference in nitrogen retention. The added cost of BCAA supplementation, along with the lack of an effect upon nitrogen accretion, indicates that greater benefits must be demonstrated before widespread use of BCAA supplementation can be recommended in the injured patient.

Carnitine femoral arterial-venous differences in the stressed critically ill

Femoral arterial and venous carnitine concentrations from critically ill patients were measured in order to determine if the large urinary carnitine excretions seen in these patients was associated with a net loss of carnitine from skeletal muscle. Bloods were drawn two or three times during the 7-day study period. A 24-hr urine sample was obtained on the same day. The arterial-venous difference for free carnitine plus short chain acylcarnitine was -2.8 +/- 0.9 microM (means +/- SEM), and -2.7 +/- 1.0 microM for total carnitine. Both values were significantly less than zero (p less than 0.05). Median urinary free carnitine excretion was 1237 mumol/day while the median acylcarnitine excretion was 544 mumol/day. We conclude that skeletal muscle in these patients is in negative carnitine balance, and is at least one source of the increase in carnitine excretion seen in critically ill patients.

Increased plasma carnitine in trauma patients given lipid-supplemented total parenteral nutrition

The purpose of this study was to determine the effects of altering the fuel substrate mix of total parenteral nutrition (TPN) on plasma and urinary carnitine in trauma patients. TPN solutions were either 100% carbohydrate (CHO) based or lipid based (70% CHO, 30% lipid). There were statistically significant (p less than 0.05) increases in plasma levels of free carnitine, short-chain acyl carnitine, and total carnitine in trauma patients receiving lipid-based TPN. No significant differences in urinary carnitine excretion were noted between groups. We conclude that the use of lipids in the TPN of trauma patients leads to an alteration in plasma carnitine metabolism.

Addition of branched-chain amino acids to parenteral nutrition of stressed critically ill patients

We compared the efficacy of a total parenteral nutrition solution supplemented with 44.6% branched-chain amino acids (BCAA) to standard total parenteral nutrition (19.0% BCAA) in the support of critically ill patients. After a 4-day administration of a randomly assigned solution, amino acids were assayed from femoral venous and arterial samples. The BCAA-supplemented solution caused increases in arterial concentrations of valine, isoleucine, and leucine compared to the control solution. The femoral arteriovenous differences for these BCAA were more positive in patients given the control solution. There were no significant differences in nitrogen balance. Since previous studies showing promotion of nitrogen balance with BCAA did not use a balanced substrate for nonprotein caloric support, the lack of a significant difference in the present study may be due to effective utilization of lipid as a fuel source by both groups.

Maturation of sympathetic neurotransmission in the rat heart. IV. Effects guanethidine-induced sympathectomy on neonatal development of synaptic vesicles, synaptic terminal function and heart growth

Sympathetic nerve input has been proposed to regulate cardiac growth and differentiation. In the present study, this hypothesis was tested by giving the neurotoxic adrenergic neuron blocking agent, guanethidine (50 mg/kg, s.c.), daily to rats for 21 consecutive days to produce long-term peripheral sympathectomy in neonatal rats. Ontogeny of the sympathetic nerve terminal was measured by the ablity of synaptic vesicle preparations to take up radiolabeled norepinephrine, and heart growth in the sympathectomized animals was monitored by organ weight as well as by RNA and protein synthesis. Guanethidine treatment produced a massive sympathectomy, as synaptic vesicle development was totally arrested; the functional consequence of this treatment was confirmed by the attenuation of chronotropic responses to tyramine, a drug which acts by displacement of norepinephrine from the noradrenergic terminal. Despite the clear-cut effectiveness of guanethidine to prevent formation of functional sympathetic innervation of the heart, no significant alterations in heart growth or RNA and protein synthetic capabilities were observed in the developing rats. These results suggest that the presence of sympathetic innervaton is not obligatory for normal growth of the heart to occur.